LAPORAN TAHUNAN PENELITIAN MASTER PLAN PERCEPATAN DAN PERLUASAN PEMBANGUNAN EKONOMI INDONESIA (MP3EI)

LAPORAN TAHUNAN PENELITIAN MASTER PLAN PERCEPATAN DAN PERLUASAN PEMBANGUNAN EKONOMI INDONESIA (MP3EI)

Intervensi Teknologi Nanopartikel Pada Limbah Biomassa Sawit dan Mineral Alam Peningkatan Kualitas Produksi Minyak dan Optimalisasi Pengolahan Limbah Cair Pabrik Kelapa Sawit

Tahun ke 1 dari rencana 3 tahun

Ketua : Anggota :

Dr. Syaifullah Muhammad, ST, M.Eng / NIDN : 0015057102 1. Dr. Ir. Izarul Machdar, M.Eng / NIDN : 0020096502 2. Sofyana, ST, MT / NIDN : 0026067103 3. Ernawati, SP, M.Si / NIDN : 0003107403

UNIVERSITAS SYIAH KUALA DARUSSALAM BANDA ACEH NOPEMBER 2014

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RINGKASAN Sebagai produsen kelapa sawit terbesar di dunia, Indonesia memasok 48% dari kebutuhan Crude Palm Oil (CPO) di pasar internasional. Dari jumlah tersebut Koridor Ekonomi (KE) Sumatera yang di dalamnya termasuk propinsi Aceh, menyumbang 96 % total produksi CPO nasional. Posisi ini membuat industry kelapa sawit merupakan penyumbang devisa terbesar untuk sub sektor pertanian dan perkebunan. Hanya saja, produk CPO Indonesia dianggap masih kurang berkualitas baik karena memiliki Deterioration Of Bleachability Index (DOBI) di bawah angka 3, sesuai dengan klasifikasi yang dikeluarkan oleh Codex Allimentariurs Commision, suatu badan dunia yang memberikan standarisasi untuk produk CPO. Selain itu, industri kelapa sawit masih dianggap kurang ramah lingkungan karena menimbulkan beberapa pencemaran dan kerusakan terhadap lingkungan. Karena itu peran serta berbagai stage holder industri kelapa sawit khususnya para ilmuan dan peneliti di bidang ini cukup penting, untuk melakukan berbagai inovasi teknologi terhadap peningkatan kualitas CPO dalam negeri sekaligus mampu meningkatkan pereonomian masyarakat dan menjaga kelestarian lingkungan. Penelitian yang berjudul Intervensi Teknologi Nanopartikel Pada Limbah Biomassa Sawit dan Mineral Alam Untuk Peningkatan Kualitas Produksi Minyak dan Optimalisasi Pengolahan Limbah Cair Pabrik Kelapa Sawit ini dalam jangka pendek diharapkan mampu memberdayakan limbah biomassa kelapa sawit sehingga lebih bernilai ekonomis serta memperoleh data-data scientific penerapan teknologi nano partikel dalam proses produksi CPO. Untuk jangka panjang, teknologi ini diharapkan akan dapat dialihkan dan diimplementasikan pada industri kecil, menengah dan besar, sehingga CPO Indonesia berkualitas tinggi, meningkatkan kesejahteraan bangsa sekaligus ramah terhadap lingkungan. Sesuai dengan Surat Penugasan Pelaksanaan Penelitian Nomor 222/UN11.2/LT/SP3/2014, maka sejak bulan Mei 2014, penelitian ini telah mulai dilaksanakan pada laboratorium Sumber daya Energi Jurusan Teknik Kimia dan Jurusan Fisika Fakultas MIPA Universitas Syiah Kuala Banda Aceh. Sesuai dengan target penelitian untuk tahun pertama sebagaimana yang tercantum dalam proposal penelitian, 1 unit prototype reaktor pirolisis untuk memproses limbah bio massa kelapa sawit menjadi karbon aktif telah dihasilkan dan diuji. Beberapa jenis nano partikel juga sudah diproduksi dan dikarakterisasi dan akan dilanjutkan dengan pengujian kinerja nonopartikel tersebut dalam proses pemucatan CPO dan pengolahan limbah cair pabrik CPO melalui adsorpsi dan oksidasi. Selain itu, output dalam bentuk manuskrip yang telah dihasilkan adalah: 1 paper telah dipublikasi pada Proceeding Konferensi Internasional di Unsri Palembang, 10-11 September 2014, 1 draft paper untuk jurnal internasional, 1 draft paper untuk jurnal nasional terakheditasi dan 1 draft buku ajar tentang pengembangan teknologi nano partikel.

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PRAKATA Laporan kemajuan penelitian MP3EI yang berjudul Intervensi Teknologi Nanopartikel Pada Limbah Biomassa Sawit dan Mineral Alam Untuk Peningkatan Kualitas Produksi Minyak dan Optimalisasi Pengolahan Limbah Cair Pabrik Kelapa Sawit ini dimaksutkan sebagai bahan monitoring dan evaluasi untuk mengukur pencapaian penelitian. Dari 5 tahapan penelitian yang direncanakan yaitu: 1. Pembuatan prototype reactor pirolisis untuk memproduksi limbah padat biomassa kelapa sawit menjadi arang (karbon). 2. Pembuatan arang aktif (activated carbon) dari reactor pirolisis dilanjutkan dengan pembuatan nano activated carbon dan nano zeolite. 3. Pembuatan nano particle dengan fase aktif dengan metode impregnasi dan pertukaran ion (ion exchange) 4. Pengujian adsorpsi menggunakan nano partikel terhadap CPO melalui pemeriksaan kadar air, kadar asam lemak bebas, bilangan iod, kadar kotoran, warna, bau dan rasa. Dari pemeriksaan ini diharapkan akan diperoleh peningkatan Deterioration of Bleachability Index (DOBI) sesuai standar yang diharapkan. 5. Pengujian adsorpsi and advance oxidation process pada limbah cair pabrik CPO. Sesuai dengan target pada tahun pertama, penelitian telah memasuki tahapan ke tiga dari lima tahapan di atas, sehingga dalam tahun selanjutnya, diperkiranan seluruh tahapan penelitian yang direncanakan dapat terlaksana. Bila diukur dengan prosentase, maka tahapan penelitian yang telah dilaksanakan pada tahun pertama sudah mencapai 95%. Beberapa output penelitian yang telah dihasilkan antara lain 1 paper telah dipresentasikan pada konferensi internasional di Unsri Palembang (SESIIST 2014), 2 buah draft paper akademik untuk jurnal nasional terakreditasi dan jurnal internasional, 1 draft buku ajar, 1 unit prototype reactor pirolisis, dan beberapa produk nano partikel. Dengan dukungan DIKTI, semoga penelitian ini dapat berjalan dengan baik sesuai yang direncanakan.

Banda Aceh, 15 Nopember 2014

TIM PENELITI

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DAFTAR ISI HALAMAN SAMPUL HALAMAN PENGESAHAN RINGKASAN PRAKATA DAFTAR ISI DAFTAR TABEL DAFTAR GAMBAR DAFTAR LAMPIRAN

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BAB 1. PENDAHULUAN

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BAB 2. TINJAUAN PUSTAKA

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BAB 3. TUJUAN DAN MANFAAT PENELITIAN

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BAB 4. METODE PENELITIAN 4.1 Karakterisasi nanopartikel dan uji mutu CPO 4.2 Degradasi Pencemar Limbah 4.3 Luaran dan Indikator Penelitian

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BAB 5. HASIL YANG DICAPAI a. Struktur manajerial research project b. Prototype reactor pirolisis c. Test run reactor pirolisis dan produksi arang aktif dari cangkang sawit d. Produk nanopartikel e. Karakterisasi XRD Karbon Aktif f. Karakterisasi XRD Natural Zeolite g. Draft Buku Ajar h. Draft paper akademik

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BAB 6. RENCANA TAHAPAN BERIKUTNYA

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BAB 7. KESIMPULAN DAN SARAN

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DAFTAR PUSTAKA

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LAMPIRAN

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DAFTAR TABEL

Tabel 1. Relasi nilai DOBI dengan Kualitas CPO

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Tabel 2. Luaran dan Indikator dari Penelitian

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DAFTAR GAMBAR

Gambar 1. Skema Tahapan Penelitian Tahun Pertama

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Gambar 2. Struktur Manajerial Research Project MP3EI

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Gambar 3. Reaktor Pirolisis Set

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Gambar 4. Uji Reaktor Pirolisis

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Gambar 5. Produk Nano Karbon Aktif dari Cangkang Sawit

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Gambar 6. XRD Pattern dari Karbon Aktif Cangkang Sawit

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Gambar 7. XRD Pattern dari Karbon Aktif Batok Kelapa

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Gambar 8 XRD Pattern untuk natural zeolite

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DAFTAR LAMPIRAN 1. Personalia tenaga peneliti beserta kualifikasinya

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2. Published Paper on International Conference SISSEEST, 10-11 Septermber 2014, Palembang, Hydrothermal Synthesis of Nanocrystalline Zeolite 26 3. Draft academic paper 1: Organic Pollutant Degradation on Heterogeneous Catalytic Oxidation by using Cobalt-Natural Zeolite Catalyst (Syaifullah Muhammad, Izarul Machdar, Sofyana) 34 4. Draft academic paper 2: Teknologi Nanopartikel Meningkatkan Nilai Ekspor Crude Palm Oil (CPO) dan Tandan Buah Segar (TBS) Kelapa Sawit Indonesia 4,7 Trilyun (Ernawati, Syaifullah) 42 5. Draft Buku Ajar Nanopartikel Teknologi

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BAB 1. PENDAHULUAN 8

Dua hal yang akan menjadi focus perhatian dalam usulan proposal penelitian ini adalah peningkatan kualitas produksi CPO dan penanggulangan limbah dari pabrik minyak kelapa sawit. Rendahnya kualitas CPO merupakan salah satu masalah yang masih dialami oleh industri minyak kelapa sawit di Indonesia. Di pasar internasional CPO dari Indonesia selalu mengalami pemotongan harga Rp.200–Rp.300 perkilogram, karena standar Deterioration Of Bleachability Index (DOBI) yang tidak terpenuhi. DOBI adalah indek kepucatan minyak sawit mentah yang merupakan rasio serapan adsorbent terhadap asam lemak bebas. DOBI indeks CPO Indonesia rata-rata adalah 2,8 sedangkan DOBI dengan kategori baik adalah 2,93–3,23 berdasarkan standar Codex Allimentariurs Commision. Rendahnya DOBI indeks ini akibat efisiensi proses dan teknologi produksi CPO yang digunakan. Selain persoalan Asam Lemak Bebas, warna, aroma, bau, kadar air dan serat pada CPO adalah masalah lainnya yang perlu diperhatikan. Penyebab utama warna kuning kemerahan-jingga yang terdapat pada CPO adalah kandungan β – karoten dalam jumlah yang relatif tinggi yaitu sekitar 500-700 ppm. Selain itu CPO juga mengandung sedikit air dan serat halus sehingga tidak dapat digunakan secara langsung sebagai bahan pangan maupun non pangan (Morcillo dkk, 2013). Persoalan besar lainnya dalam industry CPO adalah limbah cairnya. Hampir seluruh komponen pada limbah berada pada ambang batas yang diperkenankan oleh Kementrian Lingkungan Hidup RI, sehingga harus diproses lebih lanjut sebelum dibuang ke lingkungan (Deptan RI, 2006). Penelitian yang berjudul Intervensi Teknologi Nanopartikel Pada Limbah Biomassa Sawit dan Mineral Alam Untuk Peningkatan Kualitas Produksi Minyak dan Optimalisasi Pengolahan Limbah Cair Pabrik Kelapa Sawit ini akan mencoba mengkaji penerapan nanoparticle technology untuk menjawab dua persoalan di atas. Limbah padat kelapa sawit akan diproses menjadi nano activated carbon dan juga difariasikan dengan nonozeolite sebagai bahan untuk meningkatkan DOBI dari CPO. Selain itu, kedua nanosize particle tersebut akan digunakan sebagai bahan untuk pengolahan limbah cair pabrik CPO melalui Adsorption and Advance Oxidation Technology. Secara umum penelitian ini bertujuan untuk menghasilkan dan menerapkan nano partikel teknologi untuk meningkatkan kualitas produksi CPO dan juga peningkatan kualitas pengolahan limbah cair parik CPO sehingga kualitas produksi yang tinggi dan environmental sustainability dari industri minyak kelapa sawit Indonesia dapat diperoleh. Beberapa tujuan yang lebih khusus dan terinci dipaparkan berikut ini: 1. Mengolah limbah padat kelapa sawit untuk menjadi activated carbon melalui rancang bangun reaktor pirolisis dan memprosesnya lebih lanjut menjadi nano activated carbon serta memproses mineral alam zeolite menjadi nanozeolite. 2. Melakukan treatmen terhadap nano activated carbon dan nano zeolite baik secara impregnasi, calcinasi ataupun ion exchange dengan fase aktif tertentu. 3. Menggunakan nano activated carbon dan nano zeolite untuk meningkatkan Deterioration of Bleachability Index (DOBI) dan parameter kualitas dari CPO lainnya sehingga daya saing CPO Indonesia di pasar internasional meningkat. 4. Menggunakan nano activated carbon dan nano zeolite untuk pengolahan limbah cair parik CPO melalui Adsorption and Advance Oxidation Technology sehingga Pabrik CPO menjadi lebih ramah lingkungan. 5. Reaktor pirolisis penghasil activated carbon dapat dikelola oleh masyarakat umum sehingga meningkatkan pendapatan mereka. Dari uraian diatas, beberapa urgensi dari penelitian ini antara lain, pertama, dapat melakukan pemanfaatan limbah padat kelapa sawit dan zeolite alam yang tidak/kurang bernilai ekonomis, menjadi produk yang memiliki manfaat besar yaitu nano activated carbon dan nanozeolite. Kedua, meningkatkan kualitas CPO Indonesia sehingga lebih bersaing secara ekonomis di pasar internasional. Dan ketiga, penerapan Adsorption and Advance Oxidation Technology untuk pengolahan limbah pabrik CPO sehingga membantu penyelamatan lingkungan.

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BAB 2. TINJAUAN PUSTAKA Karbon aktif adalah bentuk kasar dari grafit dengan struktur morphology acak atau amorf dan sangat berpori dengan luas permukaan yang cukup besar. Satu gram karbon aktif dapat memiliki luas permukaan antara 500 m2 sampai 2000 m2. Karena porositas tinggi , karbon aktif ini banyak digunakan sebagai adsorben dan penyangga katalis. Adsorpsi menggunakan karbon aktif telah terbukti menjadi salah satu metode pengolahan air limbah yang paling efektif dan dapat diandalkan secara fisiokimia. Jika karbon digunakan sebagai katalis maka faktor yang paling menentukan adalah komposisi kimia dari fase aktif yang tersebar pada permukaan karbon (Kadirvelu dkk, 2005). Banyak laporan riset yang menampilkan efektivitas Activated Carbon dalam proses pengolahan limbah organik. Bahkan saat ini, AC tanpa perlu menambah fase aktif juga telah digunakan untuk degradasi berbagai pencemar organik. Activated Carbon juga paling banyak digunakan untuk meyerap berbagai jenis bahan dalam dalam larutan termasuk sebagai bleaching agent dalam pengolahan CPO menjadi minyak makan (Muhammad dkk, 2012, Saputra dkk, 2013, Murphy, 2009). Karbon aktif dapat dibuat dari tempurung kelapa, arang kayu, lignin, kokas minyak bumi, char tulang, gambut, serbuk gergaji, karbon hitam, dedak beras, gula, limbah ikan, pupuk, ban karet limbah, dan biomassa lainnya (Juntgen, 1998). Karena itu, limbah padat kelapa sawit berupa cangkang, serat, tandan kosong atau batang tua dapat diproses menjadi activated carbon melalui teknologi pirolisis. Selama ini pemanfaatan limbah padat kelapa sawit dilakukan secara terbatas dan belum optimal sehingga banyak yang terbuang, dibiarkan membusuk dan dibakar (Machdar dkk, 2011). Pada pirolisis, biomassa limbah padat kelapa sawit akan terdekomposisi dengan temperature tinggi dalam kondisi tanpa oksigen hingga menghasilkan arang (carbon), uap dan aerosol (Bridgwater dan Kuester, 1991). Agar proses pirolisis ini berjalan dengan baik, beberapa hal harus diperhatikan antara lain, suhu dan laju perpindahan panas harus tinggi berkisar pada 400-5000C. Untuk itu perlu menggunakan temperature control agar suhu tetap pada range yang ditentukan (Bridgwater, 2003). Selanjutnya arang (karbon) yang dihasilkan dalam proses pirilisis tersebut dapat diaktivasi baik secara fisik ataupun kimia. Aktivasi fisik melibatkan tahap karbonasi pada suhu 400-600 °C untuk menghilangkan hal-hal yang mudah menguap dari struktur pori karbon. Dilanjutkan dengan gasifikasi pada temperature yang lebih tinggi. Proses ini akan Meningkatkan porositas dan luas permukaan dari karbon mentah. Di sisi lain, aktivasi kimia melibatkan bahan kimia anorganik seperti seng klorida (ZnCl2) atau asam fosfat yang ditambahkan ke prekursor diikuti dengan proses karbonisasi pada kisaran suhu 200-800 ° C. Banyak senyawa kimia lainnya dapat digunakan untuk aktivasi karbon seperti garam amonium, borat, kalsium oksida, senyawa besi dan besi , mangan dioksida , garam nikel , asam klorida , asam nitrat dan asam sulfat (Pala dan Tokat, 2002). Selain Activated Carbon, material lainnya yang juga memiliki porositas dan luas permukaan yang besar dan banyak digunakan sebagai adsorbent dan katalis adalah zeolite. Zeolit yang terdiri dari AlO4 dan SiO4 tetrahedral adalah kristal alminosilicate yang mengandung pori-pori dan rongga pada dimensi molekuler (Cundy dan Cox, 2004). Zeolit banyak ditemukan sebagai mineral alam, tetapi zeolit sintetis juga paling banyak digunakan. Zeolite merepakan salah satu katalis heterogen paling penting dalam industry kimia. Sifatnya yang paling menentukan adalah selektivitas yang tinggi, mampu melakukan pertukaran ion (ion exchange) dan memilii stabilitas thermal yang tinggi. Kristal zeolit yang memiliki pori pada skala molekul, menciptakan labirin skala nano berisi air atau molekul zat lainnya. Zeolit adalah adsorben dengan kapasitas tinggi dan selektif karena mampu memisahkan molekul berdasarkan ukuran dan konfigurasi molekul. Zeolit selektif mengadsorpsi atau menolak molekul berdasarkan perbedaan ukuran molekul, bentuk, dan sifat-sifat lainnya

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seperti polaritas (Song dkk, 2004). Muhammad dkk, 2013 melaporkan bahwa natural zeolite yang diimpregnasi dengan beberapa fase aktif logam berhasil mereduksi pencemar organik dalam air limbah. Gambar 1 memperlihatkan beberapa contoh nanozeolite. Di sisi lain, perkembangan nanoteknologi telah menimbulkan banyak daya tarik di kalangan ilmuan dan peneliti sehingga menjadi salah satu area penelitian yang sangat aktif dalam sepuluh tahun terakhir. Nanoteknologi adalah ilmu dan teknik pembuatan bahan, struktur fungsional, dan perangkat pada skala nanometer. Partikel ukuran nano seperti pada activated carbon dan zeolite akan memberikan sifat unik relatif terhadap partikel tersebut dengan ukuran konvensional. Penurunan ukuran partikel dengan skala nanometer ini menyebabkan perubahan substansial dalam sifat activated carbon ataupun zeolit yang membuat mereka menjadi material yang cukup menjanjikan untuk banyak aplikasi (Muhammad dkk, 2009). Secara umum ada 2 metode dasar pembuatan partikel dalam skala nano. Yaitu membesarkan ukuran partikel dari skala larutan menjadi ukuran nano (kondensasi kimia) dan yang kedua, mengecilkan ukuran partikel besar menjadi ukuran nano (dispersi kimia atau fisik). Dalam penelitian ini metode ke dua yang akan digunakan, yaitu mempercil partikel activated carbon dan zeolite hingga berukuran pada range 10-1000 nm (Mintova, 2003). Untuk itu akan digunakan peralatan ball mill khusus yang terdapat pada Laboratorium MIPA Fisika Universitas Syiah Kuala. Untuk beberapa kasus tertentu nano partikel tersebut akan diproses lebih lanjut dengan memasukkan fase aktif dipermukaan atau struktur molekulnya dengan metode impregnasi atau ion exchange. Melalui penempatan fase aktif pada nano partikel tersebut, akan diperoleh selektivitas tinggi untuk menyerap ataupun mereaksikan komponen yang diinginkan dalam CPO dan air limbah pabrik.. Penggunaan nano partikel seperti nano activated carbon dan nano zeolite diharapkan akan mampu mengkoreksi sifat-sifat kimia-fisika dari CPO seperti warna, Deterioration of Bleachability Index (DOBI), bau, flavor, titik kekeruhan (turbidity point) dan lain-lain memenuhi standar internasional juga melakukan pengolahan air limbah pabrik CPO secara lebih efektif. BAB 3. TUJUAN DAN MANFAAT PENELITIAN Sesuai dengan target dari Masterplan Percepatan dan Perluasan Pembangunan ekonomi Indonesia (MP3EI) khususnya untuk Koridor Ekonomi Sumatera, maka penelitian ini dimaksutkan untuk meningkatkan kualitas produksi CPO dan pelestarian lingkungan. Sehingga CPO Indonesia berkualitas tinggi dan meningkatkan daya saingnya di pasar internasional. Selain itu melalui penanganan terhadap limbah, baik padat maupun cair, industri pengolahan kelapa sawit menjadi CPO ini dapat dimasukkan dalam industri yang ramah lingkungan. Selain manfaat utama tersebut, ada beberapa manfaat lainnya yang diharapkan melalui penelitian ini yaitu: 1. Berkembangnya disiplin nano science and technology sebagai cikal bakal pembentukan Nano Technology Center di Universitas Syiah Kuala. 2. Semakin baiknya jalinan kerjasama antara akademisi dan peneliti di Universitas Syiah Kuala dengan kalangan Industri khususnya Industri Pabrik Kelapa Sawit di Aceh yang membangun iklim kondusif untuk pengembangan link and match keilmuan perguruan tinggi dengan dunia usaha. 3. Mengingat sebagian besar industri kelapa sawit di Aceh juga melibatkan perkebunan rakyat, maka beberapa produk penelitian ini, seperti reactor pirolisis, nano partikel yang dihasilkan akan dapat diberikan dan dimanfaatkan untuk usaha kecil masyarakat. 4. Dari hasil penelitian akan dapat dipublikasi pada konferensi dan jurnal baik nasional maupun internasional. Juga memungkinkan untuk pembuatan buku ajar tentang penggunaan tenologi nano partikel. 11

BAB 4. METODE PENELITIAN Penelitian akan dilakukan selama tiga tahun, sampel limbah padat, CPO dan limbah cair Pabrik Minyak Kelapa Sawit akan diambil pada PT. Shaukath Sejahtera di Kabupaten Bireuen Aceh, yang memiliki pabrik pengolahan sawit menjadi CPO. Penelitian untuk skala laboratorium dilakukan pada Laboratorium Sumber Daya Energi Jurusan Teknik Kimia dan Laboratorium Fisika FMIPA Universitas Syiah Kuala. Penelitian ini 5 tahapan: 1. 2. 3. 4.

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Pembuatan prototype reactor pirolisis untuk memproduksi limbah padat biomassa kelapa sawit menjadi arang (karbon). Pembuatan arang aktif (activated carbon) dari reactor pirolisis dilanjutkan dengan pembuatan nano activated carbon dan nano zeolite. Pembuatan nano particle dengan fase aktif dengan metode impregnasi dan pertukaran ion (ion exchange) Pengujian adsorpsi menggunakan nano partikel terhadap CPO melalui pemeriksaan kadar air, kadar asam lemak bebas, bilangan iod, kadar kotoran, warna, bau dan rasa. Dari pemeriksaan ini diharapkan akan diperoleh peningkatan Deterioration of Bleachability Index (DOBI) sesuai standar yang diharapkan. Pengujian adsorpsi and advance oxidation process pada limbah cair pabrik CPO.

Untuk tahun pertama, penelitian difokuskan pada perancangan prototype reactor pirolisis untuk pengolahan limbah padat kelapa sawit menjadi arang aktif, pembuatan nano arang aktif dan nano zeolite. Skema tahapan penelitian untuk Tahun Pertama diperlihatkan pada Gambar 1 berikut ini.

Pembuatan prototype reaktor pirolisis

- Persiapan bahan dan jadwal penelitian - Perencanaan disain reactor dan diskusi dengan bengkel pembuat reactor - Konstruksi reactor - Uji running reactor - Persiapan bahan baku biomassa limbah sawit dengan kadar air dibawah 10% -

Evaluasi produk arang yang dihasilkan Evaluasi pengaruh temperature terhadap produk arang Evaluasi pengaruh bahan baku terhadap produk arang Evaluasi pengaruh waktu pirolisis terhadap produk arang Pembuatan nano Arang Aktif dan Nanozeolite Publikasi hasil penelitian pada nasional atau internasional conference - Draft buku ajar tentang proses pembuatan nano partikel dari zeolite dan arang aktif secara pirolisis Gambar 1. Skema Tahapan Penelitian Tahun Pertama

Test Run Reactor

4.1 Karakterisasi nanopartikel dan uji mutu CPO Nano partikel (Activated Carbon dan Zeolite) yang dihasilkan akan di karakterisasi menggunakan X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) dan Nitrogen 12

Adsorption-Desorption untuk mengetahui struktur, morfologi dan luas permukaan partikelnya. Kemudian untuk pengujian Deoterioration of Bleachability Index (DOBI) akan digunakan standar sebagaimana ditampilkan pada Tabel 1 berikut: Tabel 1. Relasi nilai DOBI dengan Kualitas CPO DOBI Indeks Kualitas < 1,68 Buruk 1,76 – 2,30 Kurang 2,36 – 2,92 Cukup 2,99 – 3,24 Baik > 3,24 Terbaik Sumber : Buletin Infomutu Deptan, 2004 Sampel akan diuji spektrofotometer pada panjang gelombang λ 446 nm dan pada λ 269 nm dengan menggunakan UV-Vis Instrument. Untuk melarutkan CPO akan diperunakan pelarut organik nheksana. Untuk pengujian parameter kualitas CPO lainnya, dilakukan dengan prosedur biasa yang telah lazim dilakukan berdasarkan SNI 01-2901-2006 tentang standar mutu Crude Palm Oil (CPO). Salah satu contoh metode pengujian mutu CPO yaitu kadar asam lemak bebas, diuraikan berikut ini. Sampel CPO sebanyak ± 25 gram ditambahkan 50 ml ethanol 95 % dan 3 tetes indikator pp. Selanjutnya, campuran dititrasi dengan larutan KOH 0,5 N sampai terbentuk warna merah muda yang tidak hilang selama 30 detik. Kadar asam lemak bebas dihitung dengan menggunakan rumus % asam lemak bebas (ALB) = ml KOH x N KOH x BM asam lemak x 100% berat bahan (gr) x 1000. Sebagai catatan, asam lemak bebeas dalam CPO ini dihitung sebagai asam palmitat. Dengan menggunakan SNI yang sama, parameter kualitas CPO lainnya seperti kadar air, kadar kotoran, bilanga iod dll dapat dilakukan. 4.2 Degradasi Pencemar Limbah Pengujian limbah akan dilakukan melalui melalui proses adsorpsi dan oksidasi melalui penggunaan nano partikel. Selanjutnya parameter lingungan terhadap air limbah seperti BOD, COD, pH, kandungan minyak dan lain-lain akan dievaluasi sesuai dengan standar yang dikeluarkan oleh Kementrian Lingkungan Hidup. Dalam beberapa kasus, penelitian degradasi limbah ini akan menggunakan special oxidant agent seperti Hidrogen peroksida dan oxone. Prosedur eksperimennya dijabarkan berikut ini. Mula-mula limbah cair pabrik CPO dianalisa komposisinya dengan menggunakan GC/MS (Gas Chromatography/Mass Spectrometry), persiapan sample dilakukan berdasarkan metode yang dilakukan oleh Guillen dan Ibargoitia (1999). Selanjutnya dilakukan tahapan pengujian adsorpsi dan oksidasi. Ke dalam reaktor, dimasukkan 500 mL larutan limbah CPO pada berbagai konsentrasi. Reaktor dimasukkan ke dalam water bath dengan temperature control, di aduk pada 400 rpm dan dijalankan pada berbagai fariasi temperatur. Sejumlah nanopartikel dimasukkan ke dalam reactor untuk dimulai proses adsorpsi dan/atau oxidasi. Dalam beberapa experiment, proses oxidasi akan akan melibatkan oxidant agent. Selanjutnya dalam rentang waktu tertentu, sampel diambil, 0.5 ml disaring menggunakan filter 0,45 µm, dicampur dengan 0,5 methanol sebagai quenching reagent dan selanjutnya diperiksa menggunakan instrument High Performance Liquid Chromatography (HPLC) yang ada di laboratorium Jurusan Teknik Kimia Unsyiah. Limbah di analisa menggunakan HPLC dengan detektor UV pada panjang gelombang 270 nm. Untuk mobile phase dari HPLC digunakan larutan khusus dengan komposisi 70% air dan 30% acetonitrile. Nano partikel yang digunakan dapat di recovery untuk expertimen selanjutnya sebagai reuseable material test. 4.3 Luaran dan Indikator Penelitian 13

Dengan beberapa prosedur yang telah dijabarkan di atas, maka dalam penelitian ini ditargetkan beberapa output (luaran) dan beberapa indicator capaian tahun pertama sebagaimana yang diuraikan pata Table 2 berikut. Tabel 2. Luaran dan Indikator dari Penelitian Luaran Indikator Tahun-1 Tahun-1  Disain dan rancang bangun prototype  Diperolehnya Data disain reactor pirolisis reactor pirilisis  Tersedianya 1 unit prototype reactor pirolisis  Prototype reaktor pirolisis  Diperolehnya data karakterisasi Nanopartikel  Produk Nanopartikel  Diperolehnya data penelitian tentang relasi suhu (400-6000C), jenis bio massa, ukuran  Karakterisasi Nano Partikel dan waktu pirilisis terhadap yield  Manuskrip buku ajar dan paper untuk konferensi ilmiah nasional dan  Publikasi di Conference Internasional (1 internasional manuscript)  Draft Buku ajar tentang pembuatan nano arang aktif dari biomassa sawit secara pirolisis  Dtaft Paper Jurnal Internasional  Draft Paper Jurnal Nasional Terakreditasi

BAB 5. HASIL DAN PEMBAHASAN a. Struktur manajerial research project Untuk efektivitas kerja, struktur manajemen penelitian telah dibentuk sebagaimana diperlihatkan pada Gambar 1 berikut. Manajerial research project ini terdiri dari satu ketua tim peneliti merangkap peneliti utama dibantu oleh 3 orang peneliti utama lainnya, masing masing peneliti utama pada Wastewater Treatment, bidang Peningkatan Kualitas CPO dan Peneliti Utama bidang Dampak Social Ekonomi. Masing-masing peneliti berkomitmen untuk menghasilkan 1 akademik paper per tahun, sehingga dari 4 peneliti diharapkan akan dapat dihasilkan 4 akademik paper per tahun. Selanjutnya research project ini memiliki 4 orang asisten masing-masing 2 orang mahasiswa S2 dan 2 orang mahasiswa S1 Jurusan Teknik Kimia. Selain itu project juga memiliki satu orang Project Officer yang menangani proses administrasi, koherensi kerja, pengontrolan logbook, pengaturan meeting, dokumentasi dan pelaporan keuangan. Project juga memiliki satu orang teknisi laboratorium yang membantu memastikan berjalannya proses ekperimen.

14

Gambar 2. Struktur Manajerial Research Project MP3EI

b. Prototype reactor pirolisis Gambar 3 berikut ini memperlihatkan prototype reaktor pirolisis yang telah dibuat, yang terdiri dari satu unit rekator pirolis dari stainless steel, satu unit tube furnace dan satu unit tabung gas nitrogen. Reaktor ini juga dilengkapi dengan stainless steel plate untuk proses kalsinasi.

Gambar 3. Reaktor Pirolisis Set

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c. Test run reactor pirolisis dan produksi arang aktif dari cangkang sawit Sejauh ini beberapa percobaan untuk menghasilkan nano carbon aktif dari cangkang sawit telah dilakukan pada beberapa variable seperti temperature prirolisis 400, 500 dan 6000C dengan waktu tinggal treaktor yang juga difariasikan masing-masing 2, 3 dan 5 jam. Dari percobaan ini di konfirmasi bahwa reaktor beroperasi secara efektif untuk proses pirolisis dan mampu menhasilkan arang aktif berkualitas tinggi. Percobaan memperlihatkan bahwa dari 500 gram bio massa cangkang sawit, dapat dihasilkan 150 gram karbon aktif. Beberapa aktivitas percobaan reactor pirolisis diperlihatkan pada Gambar 4 berikut ini.

Gambar 4. Uji Reaktor Pirolisis d. Produk Nanopartikel Arang yang dihasilkan dari reactor pirolisis selanjutnya di haluskan dan di saring dengan menggunakan siever ukuran 38µ, 75µ dan 150µ. Ukuran partikel karbon yang lebih kecil dari 38µ selanjutnya dibawa ke Laboratorium Fisika FMIPA untuk dijadikan ukuran nano dengan menggunakan ball mill. Berikut beberapa produk Nano Activated Carbon yang telah dihasilkan melalui proses dalam reactor pirolisis (Gambar 5).

Gambar 5. Produk Nano Karbon Aktif dari Cangkang Sawit 16

e. Karakterisasi XRD Karbon Aktif Karbon aktif juga dikarakterisasi dengan menggunakan XRD pada Laboratorium Fisika FMIPA untuk mengetahui struktur partikel dan ukurannya. Gambar 6 dan 7 berikut memperlihatkan contoh beberapa XRD Pattern yang telah dihasilkan.

12000 10000

Intensitas

8000 6000 4000

Sampel 1

2000 0 10

20

30

40

50

60

70

80

90

2 tetha

9000 8000 7000

Intensity

6000 5000 4000 3000

Sampel 2 :

2000 1000

0 0

10

20

30

40

50

60

70

80

90

2 Theta

Gambar 6. XRD Pattern dari Karbon Aktif Cangkang Sawit

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10000 9000 8000

6000 5000 4000 3000 2000

Sampel 3 :

1000 0 0

10

20

30

40

50

60

70

80

90

2 tetha

9000 8000 7000 6000 Intensity

Intensity

7000

5000 4000 3000

Sampel 4 : 2000 1000 0

0

10

20

30

40

50

60

70

80

90

2 Theta

Gambar 7. XRD Pattern dari Karbon Aktif Batok Kelapa

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f. Karakterisasi XRD Nanozeolite Selain karbon aktif, karakterisasi juga dilakukan pada Natural Zeolite sebagai mineral alam pembanding untuk mengukur efektivitas nano partikel dalam proses peningkatan kualitas CPO dan pengolahan limbah cair parik minyak kelapa sawit. Gambar 8 memperlihatkan contoh karakterisasi XRD tersebut.

Tanpa Kalsinasi Dengan Kalsinasi Pada 5500C

Gambar 8 XRD Pattern untuk natural zeolite g. Karakterisasi SEM

19

h. Karakterisasi EDS

20

i. Karakterisasi Nitrogen Adsoprtion Desorption (BET) Inprogress di ITB Bandung

j. Manuskrip 1. Draft Buku Ajar : Pengembangan Teknologi Nano Partikel. 2. Paper akademik  Telah di publish pada proceeding konferensi internasional: Hydrothermal Sybthesis of Nanocrystalline Zeolite Using Clear Solution (Presented on SISEEST, 11 September 2014, Palembang)  Draft 1 : Organic Pollutant Degradation on Heterogeneous Catalytic Oxidation by using Cobalt-Natural Zeolite Catalyst (Syaifullah Muhammad, Izarul Machdar dan Sofyana)  Draft 2 : Teknologi Nanopartikel Meningkatkan Nilai Ekspor Crude Palm Oil (CPO) dan Tandan Buah Segar (TBS) Kelapa Sawit Indonesia 4,7 Trilyun (Ernawati dan Syaifullah Muhammad)

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BAB 6. RENCANA TAHAPAN BERIKUTNYA Dalam Tahun ke-2 beberapa rencana lanjutan yang akan dilaksanakan dalam penelitian ini yaitu : 1. Impregnasi nano karbon aktif dengan fase aktif logam Cobalt dan Ruthenium 2. Pengujian nano partikel pada CPO dan air limbah 3. Penulisan artikel untuk jurnal internasional Skema tahapan penelitian selanjutnya dapat di lihat pada gambar berikut ini.

Pembuatan Arang Aktif secara fisika atau kimia dan pembuatan nano partikel Pembuatan Nanopartikel dengan fase aktif secara impregnasi dan ion exchange Pengujian Nanopartikel terhadap kualitas CPO

Pengujian Nanopartikel terhadap degradasi zat pencemar dalam limbah cair pabrik CPO

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Persiapan bahan penelitian dan jadwal kerja Evaluasi bahan baku biomassa Evaluasi ukuran pertikel Evaluasi metode aktivasi Publikasi hasil penelitian pada nasiona/internasional l conference atau jurnal nasional terakreditasi/jurnal internasional

--

Persiapan bahan penelitian dan jadwal kerja Evaluasi jenis nanopartikel Evaluasi jenis fase aktif Evaluasi metode impreksani atau ion exchange Publikasi hasil penelitian pada internasional l conference atau jurnal internasional Buku ajar tentang pembuatan nanoarang aktif dari biomassa sawit secara pirolisis Persiapan bahan penelitian dan jadwal kerja Evaluasi jenis nanopartikel Evaluasi jenis fase aktif Evaluasi sifat fisika-kimia CPO: warna, bau, rasa, dll Publikasi hasil penelitian pada internasional l conference atau jurnal internasional Persiapan bahan penelitian dan jadwal kerja Evaluasi jenis nanopartikel Evaluasi jenis fase aktif Evaluasi parameter limbah Publikasi hasil penelitian pada internasional l conference atau jurnal internasional Pembuatan Buku dan pengajuan paten sederhana Survey untuk pabrik percontohan yg menerapkan hasil penelitian

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Beberapa judul paper dipersiapkan oleh masing-masing peneliti untuk publikasi antara lain : 1. Degradasi Pencemar Organik dalam Limbah Cair Pabrik CPO dengan Menggunakan Katalis Nano Karbon Aktif 2. Peningkatan DOBI Indeks CPO menggunakan Nanopartikel karbon Aktif dari Cangkang Sawit 3. Penyerapan zat warna CPO menggunakan nanozeolite yang telah diipregnasi dengan fase aktif 4. Analisis Pendapatan Petani Kelapa Sawit di Kabupaten Bireuen : Tinjauan Pengaruh Harga Eksport CPO terhadap Tanda Buah Segaar (TBS)

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BAB 7. KESIMPULAN DAN SARAN Penelitian MP3EI ini yang berjudul Intervensi Teknologi Nanopartikel Pada Limbah Biomassa Sawit dan Mineral Alam Untuk Peningkatan Kualitas Produksi Minyak dan Optimalisasi Pengolahan Limbah Cair Pabrik Kelapa Sawit telah berjalan sesuai dengan perencanaan dan target yang ditetapkan. Sampai saat ini telah berhasil dibuat prototype reaktor pirolisis dari bahan stainless steel untuk produksi arang aktif dari cangkang sawit. Reaktor telah berhasil memproduksi beberapa sampel arang aktif dan telah dimodifikasi menjadi nano partikel melalui instrument ball mill. Luaran dalam bentuk manuskrip tahun pertama proyek penelitian ini adalah : 1 paper konferensi internasional, 1 draft paper jurnal internasional, 1 draft paper jurnal nasional terakreditasi dan 1 draft buku ajar tentang pengembangan nano partikel.

DAFTAR PUSTAKA Bridgwater A.V., Kuester J.L. (1991). Research in Thermochemical Biomass ConVersion, Elsevier Science Publishers: London Bridgwater A. V. (2003). Renewable fuels and chemicals by thermal processing of biomass. Chem. Eng. J., 91, 87-102. Buletin Infomutu Deptan, edisi Mei 2004, halaman 1 dan 7. Cundy C.S., Cox P.A. 2004, The hydrothermal synthesis of zeolites: History and development from the Earliest to the present time, Chem. Rev. 103, pp. 663-701. Edy Saputra, Syaifullah Muhammad, Hongqi Sun, Shaobin Wang, Activated carbons as green and effective catalysts for generation of reactive radicals in degradation of aqueous phenol, RSC Adv., 2013, 3, 21905 F. Morcillo, D. Cros, N. Billotte, G.-F. Ngando-Ebongue, H. Domonhe´do, M. Pizot, T. Cue´llar, S. Espe´out,R. Dhouib, F. Bourgis, S. Claverol, T.J. Tranbarger, B. Nouy & V. Arondel, Improving palm oil quality through identification and mapping of the lipase gene causing oil Deterioration, Nature Communication, 2013, | 4:2160 | DOI: 10.1038 Guillen, M. D., dan Ibargoitia, M. (1999). Influence of the Moisture Content on the Composition of the Liquid Smoke Produced in the Pyrolysis Process of Fagus sylvatica L. Wood. J. Agric. Food Chem., 47, 4126-4136. Juntgen H, Activated carbon as catalyst support. Fuel, 1998. Vol. 65, p. 1436-1446 Kadirvelu, K., Karthika, C., Vennilamani, N., Pattabhi, S., 2005. Activated carbon from industrial solid waste as an adsorbent for the removal of Rhodamine-B from aqueous solution: kinetic and equilibrium studies. Chemosphere 60(2005) p. 1009–1017. Machdar I., Fatanah, U., dan Faisal, M., (2011). Detail Enginering Design (DED) Reaktor PirolisisTempurung Kelapa untuk Industri Asap Cair Badan Usaha Milik Gampong (BUMG)Beunyot, Kabupaten Bireuen, Kapasitas 1.200 kg. Dalam: Proposal Program TERAPAN,Kerjasama Fakultas Teknik Unsyiah, ADF, BIMA, dan An’nisa Center. SubProposal for Aceh Economic Development Financing Facility, MDF-World Bank. http://www.acehedff.org/. Mintova S. 2003, Nanosized Molecular Sieves, Journal of Chem. Society, Chem. Comm. 68, pp. 2032-2054. Muhammad, S., Shukla, P.R., Tade, M.O. and Wang, S. (2012). Heterogeneous activation of peroxymonosulphate by supported ruthenium catalysts for phenol degradation in water, Journal of Hazardous Materials, 215-216, 183-190. Murphy, D. J. Oil palm: future prospects for yield and quality improvements.Lipid Technology 21, 257–260 (2009).

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Pala A., Tokat, E. Color removal from cotton textile industry wastewater in an activated sludge system with various additives. Water Res. 36(2002) p. 2920–2925 Pedoman Pengelolaan Limbah Industri Kelapa Sawit, 2006, Subdit. Pengelolaan Lingkungan Departemen Pertanian RI, hal.16-17. Song W., Justice R.E., Jones C.A., Grassian V.H., Larsen S.C. 2004, Synthesis, Characterization, and adsorption Properties of Nanocrystalline ZSM-5, Langmuir, 20, pp. 8301-8306 Stavropoulos G.G., Samaras P., Sakellaropoulos G.P. Effect of activated carbons modification on porosity surface structure and phenol adsorption, Journal of Hazardous Materials 151 (2008) p. 414–421 Syaifullah Muhammad, Edy Saputra, Hongqi Sun, H.M. Ang, Moses O. Tade, Shaobin Wang, Removal of Phenol Using Sulphate Radicals Activated by Natural Zeolite -Supported Cobalt Catalysts, Journal of Water, Air, & Soil Pollution, November 2013, 224:1721 Syaifullah Muhammad, Izarul Machdar, Yunardi, Shaobin Wang, Moses O. tade, Chromium and Lead Removal Using Synthesized Nanocristalline Zeolite, Jurnal Purifikasi, Vol. 10, No.1 Juli 2009, 49-58 Syaifullah Muhammad, 2008, Nanozeolite, Synthesis and Application, Master Thesis Chemical Engineering Curtin University Australia Statistik Pertanian 2012, Kementerian Pertanian (file:///E:/Potensi%20Kelapa%20Sawit%20di%20Aceh%20-%20Regional%20Investment.htm

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LAMPIRAN 1. Personalia tenaga peneliti beserta kualifikasinya Ketua 1 2 3 4 5 6 7 8 9 10 11

Nama Lengkap (dengan gelar) Jenis Kelamin Jabatan Fungsional NIP/NIK/No. Identitas lainnya NIDN Tempat dan Tanggal Lahir E-mail Nomor Telepon/HP Alamat Kantor Nomor Telepon/Faks Fakultas/Jurusan

Dr. Syaifullah Muhammad, ST, M.Eng L Lektor 19710515 1999031001 0015057102 Kualasimpang, 15 Mei 1971 [email protected] [email protected] 081370105276 Jln. Tgk. Syech Abdul Rauf No.7 Darussalam 0651 51977/0651 54208 Teknik/Kimia

Anggota 1 2 3 4

Nama Lengkap dan gelar Jenis Kelamin Tempat / Tanggal Lahir Alamat

5 6 6 7 8 9 10

NIP NIDN Pangkat/Golongan Jabatan Fungsional Jabatan Struktural Jurusan/Prodi Fakultas

: Dr. Ir. Izarul Machdar, M. Eng : Laki-laki : Banda Aceh, 20 September 10965 : Jln. Arifin Ahmad III No. 9 Ie Masen Kaye Adang : 19650920 199203 1 003 : 0020096502 : Penata /IV-a : Lektor Kepala :: Teknik Kimia : Teknik

1 2 3 4 5 6 7 8 9 10

Nama Lengkap (dengan gelar) Jenis Kelamin Jabatan Fungsional NIP/NIK/No. Identitas lainnya NIDN Tempat dan Tanggal Lahir E-mail Nomor Telepon/HP Alamat Kantor Nomor Telepon/Faks

Sofyana, ST., MT. P Lektor 197106261998022001 0026067103 Lubuk,Aceh Besar/26-06-1971 [email protected] 08126984683 Jln. Tgk. Syech Abdul Rauf No.7 Darussalam 0651 51977/0651 54208

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1 2 3 4 5 6

Nama Lengkap Jabatan Fungsional NIP NIDN Tempat/tanggal lahir Alamat rumah

7 Nomor HP 8 Alamat Kantor 9 Alamat E-mail

2.

Ernawati, SP, MSi. Asisten Ahli 19741003 200604 2 001 0003107403 Kualasimpang, 3 Oktober 1974 Jln. Arifin Ahmad II No. 12 Ie Masen Kaye Adang Banda Aceh 08126909062 Jln Tgk Syech Abdul Rauf, Darussalam, Banda Aceh [email protected]

Published Paper on International Conference

HYDROTHERMAL SYNTHESIS OF NANOCRYSTALLINE ZEOLITES USING CLEAR SOLUTION Syaifullah Muhammad1, Izarul Machdar1, Sofyana1, Aris Munandar1 , Edy Saputra2, Tuty Emilia Agustina3, Shaobin Wang4 and Moses O. Tade4 1

Chemical Engineering Department Syiah Kuala University Banda Aceh 2 Chemical Engineering Department Riau University 3 Chemical Engineering Department Sriwijaya University 4 Chemical Engineering Department Curtin University of Technology Western Australia [email protected] ABSTRACT Nano size particles such as nanocrystalline zeolites have unique properties relative to conventional micrometer sized zeolite crystals. The reduction of particle size to the nanometer scale leads to substantial changes in properties of zeolite which make them as promising materials for many applications. Nanocrystalline zeolite A, silicate-1 and ZSM-5 were successfully synthesiszed at temperature of 80-1500C using clear solution in the presence of organic templates. Values of 1.46, 3.06, 4.59 and 6.79 are effective Si/Al ratio to synthesis LTA zeolite. Further, high Si/Al ratio of 30, 40 and 60 were used for ZSM-5 synthesis. The product could be obtained at 1-5 day for zeolite A and ZSM-5 while silicate-1 (aluminum free) could be obtained at 5-9 day. It is proved that zeolite yields increased with increasing temperature, time, Si/Al ratio and organic template. Moreover, TEOS and Ludox LS as silica sources in the silicate-1 synthesis were found to influence the particle size. TEOS makes the zeolite particle smaller than Ludox LS. Two stage synthesis conducted on silicate-1 crystallization could decrease time and increase yield. However it is found that the average particle size was slightly higher than that in one-stage synthesis. Key words: Nanocrystalline zeolite, clear solution, organic template, one-stage synthesis 1. INTRODUCTION Nanozeolites are crystalline aluminosilicates with molecular dimension in the range of 10-1000 nm of the particle size (Mintova, 2003). Nanozeoilites have higher external surface area and reduced diffusion path lengths due to smaller particle size. The reduction of particle size to the nanometer scale leads to substantial changes in properties of zeolite which make them as promising materials for many applications.

Zeolite nanocrystals are usually synthesized under hyhrothermal condition using clear aluminosilicate solution, usually in the presence of organic compounds as templates such as tetramethylammonium (TMA) and tetrapropylammonium (TPA) (Zhan, et al. 2001). Further, Cundy and Cox (2004) reported aluminosilicate zeolites synthesized under hydrothermal condition from reactive gels in alkaline media at temperature of about 800C and 2000C and

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most high Si/Al ratio of zeolites (>10) are synthesized using organic templates, which have to be removed from the zeolites structure by calcinations. Mintova (2003) reported the synthesis of nano size zeolites including nanozeolite A (LTA), nanozeolite Y (FAU), nanozeolite silicate-1 (MFI) and nanozeolite beta (BEA) at temperatures lower than 1000C with synthesis time up to 400 hours. The successful synthesis of nanozeolite A was also reported by Rakoczy and Traa (2003) who synthesized the materials at temperature of 800C with initial Si/Al ratios of 3.05, 4.03, 5.03, 6.99 and 7.89 and particle sizes in the range of 50-100 nm. The other researchers Persson et al (1994) reported the success of nanozeolite silicate-1 synthesis with average particle size of less than 100 nm at temperature of 1550C in 29 hours. Moreover, Grieken et al (2000) reported the synthesis of nanocrystalline ZSM-5 at 1700C for 24 hours with 10-100 nm particle sizes. The initial SiO2/Al2O3 of molar ratio used in the synthesis process is 60. With the similar procedure to Grieken et al, Song et al (2004) synthesized nanocrystalline ZSM5 at temperature of 1650C with Si/Al ratio of 20. The obtained ZSM-5 particles were 15-60 nm for 120 hours synthesis time. Many other researchers reported the success of nanozeolite synthesis which indicate the interesting and promising prospect of nanozeolite technology (Tosheva & Valtchev, 2005). Figure 1 shows the description of zeolite framework and channel dimension of LTA, FAU and MFI.

Figure 1. Zeolite framework and channel dimension (pore opening), (A) LTA, (B) MFI (http://www.iza-stucture.org, retrieved: 10 August 2007) This article reports experimental studies on synthesis of nanocrystalline zeolite A, silicate-1 and ZSM-5 under hydrothermal condition using clear solution in the present of organic template. Some parameters in synthesis process such as the effects of time, temperature, initial Si/Al ratio, and specific reactant will be evaluated.

2. METHODS 2.1 Synthesis of nanozeolite A (LTA) In preparation of LTA, two typical solutions have been deployed, namely solution-1 and solution-2. The solution-1 is composed of aluminum tri-isopropoxide (Al(OiPr)3, 99.99%, Sigma-Aldrich) dispersed in distillated water and sodium hydroxide (NaOH, 1M). Furthermore, the solution was vigorously stirred for an hour. After that, TMAOH (25 wt.% in water, SigmaAldrich) was added. The solution-2 is composed of Ludox LS colloidal silica (30 wt.%, Sigma-Aldrich) and distilled water. Next, the solution-1 and solution-2 were mixed under constant stirring to produce a clear synthesis solution. The molar composition of various synthesis solutions are shown in Table. 1. Table 1. Molar composition of zeolite A synthesis solution SAMPLE

Si/Al

MOLAR COMPOSITION

LTA-1

1.46

2.92SiO2: Al2O3: 0.29Na2O: 0.58(TMA)2O: 493.57H2O

LTA-4, LTA-5, LTA-6, LTA-19, LTA-20, LTA-21

3.06

6.12SiO2: Al2O3: 0.29Na2O: 2.24 (TMA)2O: 345.36H2O

LTA-8, LTA-9, LTA-10, LTA-11, LTA-23, LTA-24, LTA-25, LTA-26

4.59

9.18SiO2: Al2O3: 0.29Na2O: 2.8 (TMA)2O: 458.9H2O

LTA-14, LTA-15, LTA-16

6.79

13.58SiO2: Al2O3: 0.23Na2O: 4.48(TMA)2O: 538.59H2O

LTA-28, LTA-29, LTA-30, LTA-31

3.06

6.12SiO2: Al2O3: 0.25Na2O: 2.24(TMA)2O: 359.73H2O

LTA-33, LTA-34, LTA-35, LTA-36

4.59

9.18SiO2: Al2O3: 0.31Na2O: 2.80 (TMA)2O: 461.58H2O

Then, the solution was put in a stainless steel autoclave (100 ml) for crystallisation at temperature of 800C, 1200C and 150 0C in an oven. The autoclave was subjected to varying crystallisation time, from 1 day to 5 days. The product was then separated from solution in a centrifuge with 4700 rpm for 3 hours. Repeated rinsing and centrifugation for 4 times were done to purify the product and finally filtration was employed to obtain the nanozeolite A product. next, the product was dried at 120 0C for 24 hours and then calcined at temperature of 550 0C for 3 hours.

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2.2 Synthesis of nanozeolite silicate-1 (MFI) Synthesis solution was made by adding tetrapropylammonium hydroxide (TPAOH, Sigma Aldrich) into silica sources (Ludox LS or TEOS) and followed by strong mixing. The solution was then added by distilled water and ethanol. If the silica source is TEOS (tetraethyl orthosilicate), the synthesis solution was shaken for 12 hours on a shaker. The synthesis mixtures with molar composition 2TPAOH: 0.15Na2O: 6SiO2: 532H2O: 51EtOH (Ludox LS as silica source) and 2TPAOH: 0.15Na2O: 4.5Si: 382H2O: 51EtOH (TEOS as silica source) were obtained. In the next step, the synthesis mixture was transferred to the crystallization vessel and heated in an oven at temperatures of 800C, 1200C and 1500C. After a certain synthesis time, the product was separated from mother liquor by centrifuge at 4700 rpm for 2 hours. The solid phase was then rinsed up to 5 times and filtered. After that, the product was dried at 120 0C for 24 hours and then calcined at temperature of 600 0C for 3 hours. The temperatures of 80 0C and 1200C were used for two stages synthesis period with varying of temperatures where 3, 4 and 5 days synthesis time were used at 800C as the first stage and another 1 day was used at 1200C as the second stage.

separated by using the centrifuge at 4700 rpm for 2 hours. After that the samples were rinsed for 4-5 times. The next step is drying of the samples at 1200C for 24 hours and calcinations at 6000C for 3 hours. 2.4 Sample Characterization X-Ray Diffraction (Siemen D501 XRD) and Scanning Electron Microscopy (SEM) were used to identify the synthesised product (structure and size). The specimens were mounted in standard plastic holder. The XRD patterns were recorded using Curadiation (40kV, 30mA) over a two–theta angular range of 5-700 at 0.040/2s. The measured diffraction patterns were interpreted by using the PDF Database sets 1-52, Jade6.0 and CSM search/match software. SEM (Philips XL30) was used to obtain a visual image of the samples with magnification in range of 30,000 to 75,000. The measurements of the particle size are done by using the software of Image pro plus version 4.1.0.0 onto the SEM images. 3. RESULTS 3.1 Synthesis of nanozeolite A (LTA) Effects of crystallization time and temperature

2.3 Synthesis of nanozeolite ZSM-5 (MFI) ZSM-5 synthesis was started by adding aluminum isopropoxide (Al(OiPr)3) into the mixture of distilled water and tetrapropylammonium hydroxide (TPAOH). After a clear solution was obtained with stirring at room temperature, ethanol was then added into the solution followed by adding sodium hydroxide. And then, TEOS as silica source was added and stirred for 24 hours to ensure complete hydrolysis of TEOS. The molar composition of synthesis solution is depicted in Table 2. Table 2. Molar composition of ZSM-5 synthesis solution SAMPLE

Si/Al

ZSM5-1, ZSM5-2

30

1.48TPAOH: 0.33Na2O: 0.49Al: 14.4Si: 656.83H2O: 97.68EtOH

ZSM5-3, ZSM5-4

40

1.48TPAOH: 0.33Na2O: 0.24Al: 9.6Si: 656.83H2O: 97.68EtOH

ZSM5-5, ZSM5-6

60

1.48TPAOH: 0.33Na2O: 0.24Al: 14.4Si: 656.83H2O: 97.68EtOH

The first investigation result obtained in this report shows that nanocrystalline zeolite A can be synthesised effectively at temperatures of 800C-1500C with initial Si/Al ratio of 1.46, 3.06, 4.59 and 6.79. The following figure displays three XRD profiles of nanocrystalline zeolite A with initial Si/Al ratio of 3.06 at varying temperatures. According to the XRD patterns in Figure 2, zeolite A crystal can be obtained. This fact proves that the specific condition such as temperatures of 80, 120 and 1500C, crystallization time of 5 days and initial Si/Al ratio of 3.06 is the effective condition to synthesis nanozeolite A crystal.

MOLAR COMPOSITION

Finally the synthesis solution was transferred into the bottle and put into an oven for crystallization at 900C. After a certain time, the samples were taken and

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It is found that at temperatures of 80 0C and 1200C no crystal can be recorded after 2 days. On the other hand, some LTA nanocrystal with average particle size of 104.8 nm can be obtained at 1500C after 2-day crystallization. At 5-day crystallization time, the LTA crystals are 370.04 nm, 384.26 nm and 521.65 nm at 800C, 1200C and 1500C respectively. At 800C, the LTA nanocrystal grows at 104.7 nm, 124.85 nm and 370.04 nm for 3, 4 and 5 day crystallization time, respectively. A similar trend can also be seen for the temperature of 1200C, the LTA crystal changes at 110.35 nm, 136.1 nm and 384.26 nm respectively for 3, 4 and 5 days. Moreover, at 1500C, the crystals are at size of 104.8 nm, 127.65 nm, 400.37 nm and 521.65 nm for 2, 3, 4 and 5 days crystallization time, respectively. Figure 2. XRD patterns of nanocrystalline zeolite A at 800C, 1200C and 1500C Nanocrystalline zeolite A products are also confirmed by SEM image where the visual structures shown in form of cubical which are similar to the zeolite A or linde A (LTA) crystal. Figure 3 describes the SEM images of LTA-6, LTA-21 and LTA-31 with average particle sizes of 370.04 nm, 384.26 nm and 521.65 nm, respectively. It can be seen from the pictures that higher crystallization time and temperature will result in the increase of average particle size. However, for LTA-6 and LTA-21 the difference of the average particle size is not significant.

The crystallization temperature also affects the yield of zeolite nanocrystal. Figure 4 shows correlation between temperature and yield of LTA nanocrystal. According to the curve, LTA yield increases with increasing crystallization time and also increase of temperature. On the other hand, some LTA products can be recovered at 1500C after 2 days. The lowest LTA yield is 0.0964 g and the highest is 1.3761 g which were obtained at temperature of 150 0C for 2 and 5 days crystallization time. The highest yields based on silica used can be expressed at 61.16 %. This result is much better than Rakoczy & Traa (2003) who synthesised LTA nanocrystal at 800C with initial Si/Al ratio of 3.05 and obtained 11 % yield. This fact also proves that the higher crystallization temperature will produce higher zeolite yield and particle size. 1.6 1.4 LTA yield (g)

1.2 1

80C

0.8

120C

0.6

150C

0.4 0.2 0 -0.2 0

1

2

3

4

5

6

Crystallization time (day)

Figure 4. Effect of crystallization temperature on LTA yield with Si/Al ratio of 3.06 Figure 3. SEM images of nanocrystalline zeolite A at 5-day crystallization time, 3.06 initial Si/Al ratio, LTA-6, 800C (A), LTA-21, 1200C (B) and LTA-31, 1500C (C)

The effect of initial Si/Al ratio The investigation proves that initial Si/Al ratio influences LTA yield and particle size. Table 3

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presents particle size and product yield of LTA-6 and LTA-11 which were synthesised at 800C for 5 days of crystallization time. The table shows that at Na2O/Al2O3 ratio of 0.3 and 0.0137 mole of (TMA) 2O (Organic template), LTA-11 (Si/Al=4.59) has 1.1992 g yield, 20.01 % higher than LTA-6 (Si/Al=3.06) which has 0.9992 g yield. Similar result can also be shown from LTA-21 and LTA-26, which were synthesised at temperature of 1200C for 5 days of crystallization. It can be seen that the increase of Si/Al ratio from 3.06 to 4.59 also resulted in an increase of LTA yield from 1.2032 g (LTA-21) to 1.3562 g (LTA-26) or by increased of 12.72 %. Table 3. Effect of initial Si/Al ratio on LTA yield and average particle sizes Temp.

Si/Al

Yield

(mole/mole)

(g)

LTA-6

3.06

0.9992

370.04

LTA-11

4.59

1.1992

163.45

LTA-21

3.06

1.2032

384.26

LTA-26

4.59

1.3562

181.79

Samples (0C)

Particle Size (nm)

80

120

Furthermore, initial Si/Al ratio also affects the average particle size of LTA nanocrystal. Table 3 shows that the increase of Si/Al ratio in the synthesis mixture will produce smaller particle size which can be ascribed to the less amount of aluminum content and slower crystal growth rate. At the temperature of 800C, LTA-11 (Si/Al=4.59) has the average particle size of 163.45 nm or 55.83% smaller than LTA-6 (Si/Al=3.06) which has 370.04 nm. The similar trend can also be found from LTA-21 and LTA-26. In those samples, the increase of Si/Al ratio from 3.06 to 4.59 results in decreasing of average particle size from 384.26 to 181.79 nm or a reduction of 52.69%. In spite of a slight difference in Na2O/Al2O3 ratio and organic template content (TMA cation) as is mentioned LTA samples above, synthesis of LTA nanocrystal at initial Si/Al ratio of 6.79 was also carried out. XRD pattern and SEM image show that the LTA nanocrystal can also be obtained. However, according to XRD result, the product also contains amorphous material (LTA-16). This is probably because of the high molar composition of Si/Al ratio (6.79) compared with other products such as LTA-1 (Si/Al=1.46), LTA-6 (Si/Al=3.06) and LTA-11

(Si/Al=4.59) and suggests that the large amount of silica source results in the precipitation of amorphous silica. 3.2 Synthesis of nanozeolite silicate-1 (MFI) In this research, it was found that synthesis of silicate-1 nanocrystal takes longer crystallization time than crystalline zeolite A and ZSM-5. The silicate-1 nanocrystal product can be obtained after 5-day crystallization. In this report abbreviation SIL is used to describe silicate-1 nanocrystal products such as SIL1, SIL-2, SIL-3 etc. The focuses on the effect of time, temperature (800C, 1200C and 1500C), silica source (Ludox LS and TEOS) and two-stage synthesis will be elaborated further. Effect of crystallization time and temperature It is well known that synthesis time and temperature directly affect the crystallization process. Higher product yield and bigger particle size will be obtained at longer synthesis time and higher temperature. This tendency could be found based on samples of SIL-9, SIL-10, SIL-11 and SIL-12 which were synthesised at 1200C by using Ludox LS as silica source. XRD patterns of the samples are shown in Figure 5.

Figure 5. XRD patterns of silicate-1 crystals The yields of SIL-9, SIL-10, SIL-11 and SIL-12 are 0.4065 g, 0.6263 g, 0.8028 g and 0.9957 g, respectively, with the particle sizes of 119.94 nm, 276.68 nm, 992.17 nm and 1678.54 nm. It can be seen that increase of crystallization time increases silicate-1 nanocrystal yields. And also similar trend regarding the average particle size with crystallization time can be seen from Figure 6, which shows the SEM image of silicate-1 nanocrystal.

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size is smaller (Persson et al, 1994). However, in this research it is found that the yields of silicate-1 crystal are lower if Ludox LS was used as silica source. For instance, SIL-13 (TEOS as silica source) has 0.2169g yield or 16.07 % based on Si used. This is lower than SIL-9 (Ludox LS as silica source) which has 0.4065g or 29.46 % yield. Similar results can also be found at SIL-2 (Ludox LS) and SIL-6 (TEOS) which were synthesised for 6 days at 800C and they have 19.38% and 18.19% yields based on Si used, respectively. Furthermore, by using TEOS, 0.0745 g silicate-1 sample with average particle size of 50.26 nm (SIL-5) can be obtained after 5 days at 800C.

Figure 6. SEM images of silicate-1 nanocrystal at 1200C, SIL-9, 5 days (A), SIL-10, 6 days (B), SIL-11, 7 days (C) and SIL-12, 9 days (D) Further, the effect of temperature on synthesis can also be reported. At 9-day crystallization the silicate-1 product weights are 0.9077 g, 0.9957 g and 0.5267 g for temperature of 800C, 1200C and 1500C, respectively. Similar trend can also be found for crystallization time less than 9 days. At temperature of 1500C it seems the products are lower than others. The reason is due to the less amounts of reactants such as TPAOH, Ludox LS, distilled water and ethanol compared with those to other temperatures. At temperature of 1500C only half amount of the reactants were used compared with 800C and 1200C. The less reactants in the synthesis mixture result in the lower products of silicate-1 crystals. However, if the yield is calculated relative to the amount of used silica, it will get yields of 30.26 %, 33.19 % and 35.11 % for 80 0C, 1200C and 1500C, respectively, after 9 day, which means a increasing yield with increasing temperature. Other information, no silicate-1 nanocrystal yield can be obtained at 800C and 5-day crystallization time while 0.4065 g (13.55%) and 0.2155 g (14.37%) yields could be obtained at 1200C and 1500C, respectively. The yields of silicate-1 obtained in this experiment are quite low. The highest percentage of yield based on silica used is 35.11 % which is much lower than 61.45 % reported by Li et al (2000). Effect of silica sources

On the other hand no product can be obtained at the same condition by using Ludox LS. It can be meant that TEOS makes shorter nucleation and crystallization time than Ludox LS. The smaller average particle size by using TEOS compared with Ludox LS can be shown from SIL-9 and SIL-13 samples which were synthesised at 1200C and 5-day crystallization and also other samples such as SIL-12 and SIL-16 at the same temperature and 9-day crystallization. The average particle size of SIL-9 and SIL-13 are 119.94 nm and 76.25 nm, respectively. It means, at the same conditions using TEOS can reduce 36.43 % of average particle size. Similar trend also can be seen for SIL-12 and SIL-16 which have average particle size of 1678.54 nm and 524.10 nm, respectively. For SIL-9 and SIL-12 samples which were synthesised at 5 and 9 days using Ludox LS, the average particle size is increased from 119.94 nm to 1678.54 nm. On the other hand, the particle size of SIL-13 and SIL-16 which were synthesised using TEOS at 5 and 9 days is increased from 76.25 nm to 524.10 nm. Thus, it is confirmed that TEOS can make smaller particle size than Ludox LS. The main reason that TEOS produces smaller crystal size is due to an average hydrodynamic diameter of 4 nm of TEOS smaller than Ludox LS of 15-19 nm (Li et al, 2000). Mintova and Valtchev (2002) also found similar results that the fast nucleation period and smaller particle size will be occurred if using TEOS. Li et al (2000) also reported the average crystal size could be reduced up to 66 % by using TEOS compared with Ludox LS. Further, at 1000C crystallization temperature, Ludox LS gave a little bit higher yield than TEOS (60.6 % yield for TEOS and 61.45 % for Ludox LS).

The use of Ludox LS and TEOS as silica sources affects yield and average particle size. It is found that by using TEOS, the nucleation is faster and the particle

31

Two stage synthesis The two stage synthesis procedure involves synthesis at 800C and then 1200C for a certain times. In this research, it is found that the two-stage synthesis has shorter crystallization time. For instance, samples SIL-25 (0.2613 g yield) and SIL-28 (0.0821 g) could be obtained in 4-day crystallization (3 days at 800C and 1 day at 1200C). This result is better than any other samples synthesised at 800C, 1200C and 1500C, 5 days crystallization. However, the average particle size produced in the two stage synthesis is bigger than that in one stage synthesis. The samples SIL 30 and SIL-10 have the average particle size of 292.87 nm and 276.68 nm, respectively. This result is different from the observation reported by Li et al (1999). They found the same average particle size but a higher yield of silicate1 in two stage synthesis. Further, this investigation shows that the effect of silica source on particle size using the two-stage synthesis is much similar to that in one stage synthesis, where TEOS gives smaller particle size while Ludox LS gives higher yield. This tendency can be reflected from samples SIL-27 and SIL-30 which used Ludox LS and TEOS as silica source, respectively. 3.3 Synthesis of nanozeolite ZSM-5 (MFI) Nanocrystalline ZSM-5 was synthesised at 900C with initial Si/Al ratios of 30, 40 and 60. Because the crystallization temperature is not much higher so glass/polypropylene bottles at 500 ml volume were chosen as vessels. In the experiment, the product can be obtained after 2-day crystallization for all samples. For instance, the samples of ZSM5-1, ZSM5-3 and ZSM5-5 at Si/Al of 30, 40 and 60 have 0.1211 g, 0.1303 g and 0.1471 g yields, respectively. These results indicate a faster crystallization time compared with another experiment reported by Song et al (2004). Song et al could obtain the product after 5-day crystallization time with average particle size of 15 nm at 1650C. According to Song’s results, crystallization process seems slow. Some factors probably influenced this process such as sodium content and Si/Al ratio. Song et al used 0.16 of Na2O/Al molar ratio as sodium content with Si/Al ratio of 20 and stainless steel autoclave as a vessel (crystallization reactor). This study used higher Na2O/Al ratio (0.67) and Si/Al ratio (30, 40 and 60) than those reported in the above research. It is well known that the more sodium content in the synthesis mixture result in the higher crystallinity and shorter crystallization time. SEM

images of ZSM5-1, ZSM5-3 and ZSM5-5 can be seen in Figure 7.

Figure 7. SEM image of ZSM-5 nanocrystal at 2 day crystallization time, Si/Al=30 (A), Si/Al=45 (B) and Si/Al=60 (C) As mentioned above, the product yield increases by increasing Si/Al ratio. On the other hand, the increase of Si/Al ratio results in the decrease of average particle size. It can be seen that ZSM5-1, ZSM5-3 and ZSM5-5 with crystallization time of 2 days having the average particle size of 674.15 nm, 395.98 nm and 217.55 nm, respectively. Similar tendency can also be seen for ZSM5-2, ZSM5-4 and ZSM5-6 with 3 days crystallization. They have average particle sizes of 1078.77 nm, 752.56 nm, and 558.98 nm, respectively. Comparing ZSM5-1 with ZSM5-2, ZSM5-3 with ZSM5-4 and ZSM5-5 with ZSM5-6, the increase of particle size in the 24 hour interval times (from 2 to 3 days) are 60.02%, 90.05% and 156.94%. It also means that in the same interval of crystallization time, the increase of average crystal size follows the order of Si/Al ratio. Figure 8 shows the XRD patterns and SEM images of the samples.

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Figure 8. XRD patterns and SEM image of ZSM-5 4. CONCLUSIONS Nanocrystalline zeolite A, zeolite silicate-1 and ZSM-5 could be successfully synthesised at temperature of 80-1500C. The product could be obtained at 1-5 day for zeolite A and ZSM-5 while silicate-1 could be obtained at 5-9 day. Beside temperature and time, zeolite nanocrystal syntheses are influenced by the molar composition of synthesis solution. Sodium content, initial Si/Al ratio and organic template composition are the important factors. The sodium content should be calculated thoroughly relative to alumina content to obtain the purity of the zeolite particularly on synthesis of zeolite A. It is proved that zeolite yields increased with increasing temperature, time, Si/Al ratio and organic template. Values of 1.46, 3.06, 4.59 and 6.79 are effective Si/Al ratio to synthesis LTA zeolite. Moreover, TEOS and Ludox LS as silica sources in the silicate-1 synthesis were found to influence the particle size. TEOS makes the zeolite particle smaller than Ludox LS. Two stage synthesis conducted on silicate-1 crystallization could decrease time and increase yield. However it is found that the average particle size was slightly higher than that in one-stage synthesis

103, pp. 663-701. [2] Grieken R.V., Sotelo J.L., Menendez J.M., Melero J.A. 2000, Anomalous crystallization mechanism in the synthesis of nanocrystalline ZSM-5, Microporous and Mesoporous material, 39,135147. [3] Li Q., Creaser D, Sterte J, 1999, The nucleation period for TPA-silicalite-1 crystallization determined by two stage varying-temperature synthesis, Microporous and Mesoporous material, 31, pp. 141-150. [4] Li Q., Mihailova B., Creaser D, Sterte J. 2000, The nucleation period for crystallization TPA-silicalite1 with varying silica source, Microporous and Mesoporous material, 40, pp. 53-62. [5] Mintova S. (2003), Nanosized Molecular Sieves, Journal of Chem. Society, Chem. Comm. 68, pp. 2032-2054. [6] Mintova S., Valtchev V. 2002, Effect of the silica source on the formation of nanosized silicalite-1: an in situ dynamic light scattering study, Microporous and Mesoporous Material, 55, 171179 [7] Persson A.E., Schoeman B.J., Sterte J., Otterstedt J.E. 1994, The synthesis of discrete colloidal particles of TPA-silicate-1, Zeolites, 14, pp. 557567. [8] Rakoczy R.A., Traa Y. (2003), Nanocrystalline zeolite A: synthesis, ion exchange and dealumination, Microporous and Mesoporous Materials 60, pp. 69-78 [9] Song W., Justice R.E., Jones C.A., Grassian V.H., Larsen S.C. 2004, Synthesis, Characterization, and adsorption Properties of Nanocrystalline ZSM-5, Langmuir, 20, pp. 8301-8306. [10] Tosheva L., Valtchev V.P. (2005) Nanozeolites: synthesis, crystallization mechanism, and applications, Chem. Mater. 17, 2494-2513. [11] Zhan B. Z., White M. A., Robertson K. N., Cameron T. S., Gharghouri M., 2001, A novel, organic-additive-free synthesis of nanometer-sized NaX crystal, Journal of Chemical Communication, pp. 1176-1177. [12] Zeolite framework and channel dimension of LTA, FAU and MFI, retrieved 10 August 2007 from http://www.iza-structure.org.

ACKNOWLEDGMENTS Author thanks to MP3EI Grant 2014 from DIKTI for supporting this research project. REFERENCES [1] Cundy C.S., Cox P.A. (2004), The hydrothermal synthesis of zeolites: History and development from the Earliest to the present time, Chem. Rev.

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3. Draft academic paper 1: Degradasi Pencemar Organik dalam Limbah Cair Pabrik CPO dengan Menggunakan Katalis Nano Karbon Aktif (Syaifullah Muhammad, Izarul Machdar, Sofyana dan Ernawati)

Organic Pollutant Degradation on Heterogeneous Catalytic Oxidation by using Cobalt-Natural Zeolite Catalyst Syaifullah Muhammad11, Izarul Machdar11, Sofyana11

1

Department of Chemical Engineering, Syiah Kuala University, Banda Aceh, Indonesia E-mail: [email protected]

Abstract Two types of catalysts based on Australia Natural Zeolite (ANZ) and Indonesia Natural Zeolite (INZ) were prepared by impregnation of 5 % of active metal cobalt. The synthesized catalysts were calcined in air at 5500C for 6 hours. The catalysts were then used to degrade phenol concentration in heterogeneous catalytic oxidation with the presence of oxone as peroxymonosulphate source. The catalysts were also characterized by several techniques such as SEM, EDS and N2 adsorption. It was found that Co-INZ and Co-ANZ are effective catalyst in activation of peroxymonosulphate to produce sulphate radicals to degrade phenol concentration. In reaction test of 5 hours, with condition of 25 ppm phenol, 0.2 g catalyst loading, 1 gram oxone, 250C and stirring speed of 400 rpm, Co-INZ and CoANZ could reduce phenol up to 100% and 70% respectively. Further, several parameters such as amount of catalyst loading, phenol concentration, oxidant concentration and temperature are found as key factors in phenol degradation. Moreover, based on the trend of phenol degradation following by kinetic study, it was proved that the pseudo first order kinetics would fit to phenol oxidation with the rate constants of 0.0106 and for 0.0033 Co-INZ and Co-ANZ respevtively. Keywords: Impregnation; heterogeneous catalytic oxidation; sulphate radical; phenol degradation Introduction One of common organic pollutant in wastewater, which generally produced by Industry such as chemical, petrochemical, and pharmaceutical, is phenol (Fortuny et al. 1998). This organic contaminant will not be easily removed by using primary and secondary treatment processes. Therefore, it is essential to be adopted the tertiary treatment such as thermal oxidation, chemical oxidation, wet air oxidation, catalytic oxidation etc, which are generally known as advanced oxidation processes (AOPs) (Shukla et al. 2010). In principle, the AOPs method will produce the harmless compound to environment such as CO2 and H2O (Chiron et al. 2000). Among the methods, heterogeneouos catalytic oxidation usually has some advantages such as can be operated at room temperature with normal pressure and high energy efficiency. Furthermore, heterogeneous catalysts can be synthesized by using cheap materials as supports such as activated carbon, silica, alumina and zeolite (Camporro et al. 1994). Among the materials, zeolites are one of the most important heterogeneous acid catalysts used in industry. Their key properties are size and shape selectivity, together with the potential for strong acidity. Zeolites also have ion exchangeable sites and highly hydrothermal stability, making them widely used for many applications such as separation, catalysis, ion exchange and adsorption (Erdem et al, 2004 & Song et al, 2004). Therefore, zeolite will be worthy to be tested as catalyst support in AOPs. Currently, most of AOPs are based on the generation of very reactive species, such as hydroxyl radicals (OH•) which oxidize a broad range of pollutants quickly and non selectively (Pignatello et al. 2006, Wang, 2008 and Pera-Titus et al, 2004). Apart from OH•, sulphate radical has also been proposed as an alternative due to its higher oxidation potential (Anipsitakis & Dionysiou, 2003). For

34

sulphate radical production, peroxymonosulphate (PMS, HSO5-) reaction with Co ions has been found to be an effective route. However, the use of cobalt metal as a catalyst to activate PMS and generate sulphate radical raises an issue of toxicity of the cobalt ions in water, because Co is one of heavy metals which causing diseases to animals and human beings. Thus, employing Co2+/PMS for oxidation of aqueous pollutants and minimizing the discharge of cobalt in wastewater require development of an efficient heterogeneous catalytic reaction by incorporating cobalt ions in a substrate. In addition, it is easy to recover the used catalysts simply by separation of the heterogeneous catalysts. In the past years, several types of heterogeneous Co catalysts including Co oxides (Anipsitakis et al. 2005 & Chen et al. 2008), Co composite (Yang et al. 2009) and supported Co catalysts have been investigated (Zhang et al. 2010, Shukla et al. 2011 & Shukla et al. 2010). This research is investigating the use of Cobalt based catalysts supported on natural zeolite by impregnation in heterogeneous catalytic oxidation process with the presence of peroxymonosulphte (using oxone) as an oxidant to generate sulphate radical for chemical mineralizing of phenol in the solution. Several key parameters in the kinetic study such as phenol concentration, catalyst loading, oxone concentration and temperature were also investigated. Materials and Methods Synthesis of Cobalt impregnated natural zeolite Cobalt-Indonesia Natural Zeolite (Co/INZ) and Cobalt-Australia Natural Zeolite (Co/ANZ) were synthesised using an impregnation method. INZ and ANZ were crushed in range of 60-100 micron meter of particle size. Then, a fix amount of cobalt nitrate (Co(NO3)2•6H2O), (Sigma-Aldrich) was added into 200 ml ultrapure water until the cobalt compound was dissolved. Next, INZ or ANZ were added into the solution and kept stirring for 24 hours. The solid was then recovered and dried in an oven at 1200C for 6 hours. Calcination of catalyst was conducted in a furnace at 5500C for 6 hours. The catalyst was stored in a desiccator until used. Characterisation of Catalyst The synthesised catalysts were characterised by SEM combined with EDS and N 2 adsorption. SEM (Philips XL30) with secondary and backscatter electron detector was used to obtain a visual image of the samples to show the texture and morphology of the catalysts with magnification up to 8000 times. The catalysts were also characterised by EDS (Energy Dispersive X-ray spectroscopy) to identify the structural features and the mineralogy of the catalysts. Further, nitrogen adsorption (Micromeritics Gemini 2360) was used to identify the pore size, pore volume and surface area (S BET). Prior to the analysis, the catalyst samples were degassed under vacuum at 2000C for 12 hours. Kinetic study of phenol oxidation Catalytic oxidation of phenol was conducted in 500 ml phenol solution with concentration of 25, 50, 75 and 100 ppm. A reactor attached to a stand was dipped into a water bath with temperature control. The solution was stirred constantly at 400 rpm to maintain homogeneous solution. Next, a fixed amount of oxidant of peroxymonosulphate (oxone, DuPont’s triple salt 2KHSO5.KHSO4.K2SO4, Aldrich) was added to the mixture until completely dissolved. Then, a fixed amount of catalysts (CoINZ or Co-ANZ) was added into the reactor for starting the oxidation of phenol. The reaction was run for 3-5 hours and at the fixed interval time, 0.5 ml of sample was withdrawn from the solution and filtered using HPLC standard filter of 0.45 µm and mixed with 0.5 ml methanol as a quenching reagent to stop the reaction. Phenol was analyzed on a HPLC with a UV detector at wavelength of 270 nm. The column is C18 with mobile phase of 70% acetonitrile and 30% ultrapure water.

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Results and Discussion Characterisation of cobalt impregnated activated natural zeolite The Co/INZ and Co/ANZ catalyst were characterized by using SEM and EDS where the result can be seen in Fig. 1 and Fig. 2. Both secondary electron (SE) and backscattered (BSE) detector were adopted to observe the dispersion of active metal on the catalyst support. By comparing between Fig. 1A and 1B, it can be seen that BSE detector produces the brighter image than SE detector at the same observed area. This brighter area refers to the presence of cobalt specks on Co/INZ particle as a catalyst support. It also implies that cobalt is well dispersed and coated on the natural zeolite. The presence of cobalt in the catalyst was also confirmed by EDS spectra as seen in Fig. 1C. However, several ESD spectra in the same sample with different spectrum source show that the active metal of cobalt dispersion was not full covering on the zeolite surface. Some spectrums confirm that there is no cobalt on the support surface particularly on the big particle size of zeolite. Supposedly, the big particle of zeolite and the less of cobalt loading in the system are the main reason on this. Similar phenomenon is also occured on Co/ANZ catalyst as seen in Fig. 2. In the same magnification, the particle size of Co/INZ seems to be smaller than Co/ANZ. The catalyst samples were also characterised by N2 adsorption to identify pore size distribution and surface area (SBET). As seen in Fig. 3, the Co/INZ has 17.948 m2/g, 0.009041 cm3/g and 20.1504 Å of surface area, pore volume and pore size, respectively. All of them are higher than that 8.1176 m 2/g, 0.003053 cm3/g and 15.0457 Å for Co/ANZ. Both catalysts have the pore radius around 20 Å, which means they are microporous materials (Mintova, 2003). Detail of pore size distribution and N2 isotherm analysis can be seen in Figure 3.

Figure 1. SEM Image and EDS Spectra of Co/INZ, (A) SE Detector, (B) BSE Detector, (C) EDS Spectra with insert of spectrum image source

36

Figure 2. SEM Image and EDS Spectra of Co/ANZ, (A) SE Detector, (B) BSE Detector, (C) EDS Spectra with insert of spectrum image source

Figure 3. N2 adsorption isotherm of Co/INZ and Co/ANZ Preliminary study of phenol oxidation Preliminary test of Co/INZ and Co/ANZ by adsorption and oxidation are presented in Fig. 4. The aqueous solution system conditions are 0.2 g catalyst loading, 1 g oxone in 500 ml phenol solution of 50 ppm, temperature of 250C and stirring speed of 400 rpm. It can be seen that both Co/INZ and Co/ANZ can adsorb organic compound of phenol despite at low concentration, less than 10% in 5 hours test. In adsorption process, Co/INZ and Co/ANZ exhibit similar efficiency, although Co/INZ slightly better than Co/ANZ. It seems the adsorption test result is well correlated with pore characteristic of zeolite where Co/INZ has bigger pore and surface area than Co/ANZ (Fig. 3). It is well known that the bigger pore (volume/diameter) and surface area of the particle, the higher adsorption efficiency is.

37

Figure 4. Phenol reduction with time in adsorption and catalytic oxidation. Reaction condition: 0.2g catalyst loading, 1 g oxone, 25 ppm phenol solution, 25oC and stirring speed of 400 rpm. It also can be seen in Fig.4 that Co/INZ and Co/ANZ do not be able to oxidize phenol in the solution without the presence of oxone as a source of pereoximonosulphate (PMS). This can be proved by a fact that phenol reduction in this system is minimal. Similar to this, oxone it self also could not induce a reaction in the system. Therefore, it is supposed that the oxidation of phenol is done by the presence of active metal cobalt together with PMS in the system. In oxidation tests, Co/INZ with the presence of PMS could degrade phenol up to 100% in 5 hours reaction time. Further, in the same interval time, Co/ANZ could reach around 70% in removal efficiency of phenol. Hence, the Co/INZ gave batter result than Co/ANZ in removing phenol. Significant degradation of phenol in the system confirms that cobalt in both catalysts can activate PMS to generate sulphate radicals (SO5-•) for removing phenol from solution (Anipsitakis et al., 2005). The supposed reaction mechanism can be seen below. NZ + HSO5− → NZ–H + SO5−• (1) NZ–Co3+ + HSO5− → NZ–Co2+ + SO5−•+ H+ (2) 2+ − 3+ −• − NZ–Co + HSO5 → NZ–Co + SO4 + OH (3) Furthermore, this research also confirms that supporting noble metal on support material such as metal oxide, activated carbon, zeolite and other surface material will increase activity the catalysts as reported by many researchers (Matatov-Meytal and Sheintuch, 1998). However, Co/INZ and Co/ANZ still have lower removal efficiency of phenol than Co/Activated Carbon (Shukla et al, 2010) and Co/Red mud catalyst (Saputra, 2011). Effects of reaction parameters on phenol removal Phenol concentration of 25, 50, 75 and 100 ppm are the first parameters measured in this experimental work. As can be seen in Fig. 5A, removal efficiency of phenol decreases with increasing phenol concentration. The 100% phenol removal can only reach at phenol concentration of 25 ppm in 5 hours by using Co/INZ catalyst. While in same duration at phenol concentration of 50, 75 and 100 ppm, removal efficiency obtained are 50, 40 and 30 %, respectively. The increase of phenol concentration, from 25 to 50 ppm, would decrease removal efficiency of 50%. The removal efficiency is also affected by amount of catalyst loading in the system. According to this research as shown by Fig. 5B, the complete removal of phenol can be reached within 5 hours with 0.2 g Co/INZ loading. While the 70% and 40% removal can be reached using 0.1 and 0.05 g Co/INZ. It means, by decreasing the catalyst amount of 2 times, the removal efficiency will decrease around 30%. The greater of catalyst amount used, the higher of phenol degradation efficiency is. Because by increase amount of catalyst loading, adsorption will increase and the availability of active site of metal to activate PMS also will increase. Similar trend would also be applied for Co/ANZ catalyst.

38

B

A

Figure 5. Phenol reduction with time in catalytic oxidation, (A) Effect of phenol concentration and (B) Effect of catalyst loading. Reaction condition : 1 g oxone, 25oC and stirring speed of 400 rpm. The other important parameters affected the removal efficiency of phenol are oxone concentration and temperature as presented in Fig. 6 and Fig 7. As commonly known that oxone contains pereoximonosulphate (PMS) compound as oxidant in the heterogeneous catalytic oxidation of phenol. Further, in the presence of Co/INZ or Co/ANZ, PMS will generate sulphate radicals (SO 5-•) followed by phenol reduction. Referring to Fig.6, it can be seen at reaction time of 3 hours, the highest removal efficiency of phenol obtained at 2g oxone and the lowest at 0.25g oxone. From this, looks the higher oxone concentration, the greater phenol removal is. However, the 0.5g oxone give better result than 1 g oxone. Moreover, by using Co/INZ catalyst, the 0.5g oxone has similar result with 2 g oxone. Based on these experimental works, the optimal amount of oxone for removing phenol by using Co/INZ and Co/ANZ catalyst is 0.5 g. Further, temperature is also key factor in organic compound oxidation. It also well known that the higher temperature, the faster of reaction rate is. Fig.7 shows the effect of temperature on phenol degradation. Significant effect on phenol removal was obtained by increasing temperature. For instance, at reaction time of 3 hours, removal efficiency of phenol removal using Co/ANZ from 25oC to 35oC and 45oC, increase from 45% to 75% and 100%, respectively (Fig. 7B). Similar trend is also obtained in Fig. 7A using Co/INZ catalyst, the removal efficiency increase from 80% at 25 oC to 100% at 35 and 45oC.

A

B

Figure 6. Effect of oxone concentration in phenol reduction, (A) Co/INZ and (B) Co/ANZ. Reaction condition : 0.2g catalyst loading, 25 ppm phenol solution, 25oC and stirring speed of 400 rpm.

39

A

B

Figure 7. Effect of temperature in phenol reduction, (A) Co/INZ catalyst, (B) Co/ANZ catalyst. Reaction condition : 0.2g catalyst loading, 1 g oxone, 25 ppm phenol solution, and stirring speed of 400 rpm. Oxidation kinetics For kinetics study, a general equation of the pseudo first order kinetics was used, as shown in equation below. (3) Where k is the first order rate constant of phenol removal, C is the concentration of phenol at various time, Co is the initial concentration of phenol. By integrating the equation above, the profile decrease in phenol concentration can be further elaborated in the following equation (Shukla et al. 2010). (4) From data fitting as seen in Fig.8, it is obtained that phenol degradation using Co/INZ and Co/ANZ catalyst can be represented by the pseudo first order kinetics. This can be validated from the values of R2, which are 0.9236 and 0.9892 for Co/INZ and Co/ANZ respectively. The rate constant (k) shows that the value of k for Co/INZ of 0.0106 is higher than Co/ANZ of 0.0033, which means the Co/INZ is able to degrade phenol more rapidly.

Figure 8. Data fitting using pseudo first order kinetic

40

Conclusions This research proves that Co/INZ and Co/ANZ are effective catalysts for degrading phenol in the presence of sulphate radical. Co/INZ has better ability of removing phenols than Co/ANZ. Phenol removal is a combination of oxidation and adsorption processes. This research also confirmed that the concentration of phenol, catalyst loading, concentration of oxidant (oxone) and temperature are important parameters that affect the reaction rate in removing phenol. Kinetic studies show that phenol oxidation on the Co/INZ or Co/ANZ follows the first order reaction. Acknowledgements Author thanks to MP3EI Grant 2014 from DIKTI, contract number of 222/UN11.2/LT/SP3/2014, for supporting this research project. References Anipsitakis G.P., Dionysiou D.D. 2003, Environ. Sci. Technol. 37, pp. 4790-4797. Anipsitakis G.P., Stathatos E., Dionysiou D.D. 2005, Journal of Physical Chemistry B 109, pp. 13052-13055. Camporro A., Camporro M.J., Coca J., Sastre H. 1994, Regeneration of an activated carbon bed exhausted by industrial phenolic wastewater, Journal of Hazardous Material 37, pp. 207214. Chen X.Y., Chen J.W., Qiao X.L., Wang D.G., Cai X.Y. 2008, Applied Catalysis B Environmental 80, pp. 116-121. Chiron S., Fernandez-Alba A., Rodriguez A., Garcia-Calvo E. 2000, Pesticide chemical oxidation: state-of-the-art, Water Research 34, pp. 366–377. Erdem E., Karapinar N., Donat R. 2004, The removal heavy metal cations by natural zeolites, Journal of Colloid Interface Science, 280, pp. 309-314. Fortuny A., Font J., Fabregat A. 1998, Wet air oxidation of phenol using active carbon as catalyst, Journal of Applied Catalyst B: Environmental 19, pp. 165-173. Mintova S. 2003, Nanosized Molecular Sieves, Journal of Chem. Society, Chem. Comm. 68, pp. 2032-2054 Pera-Titus M., Garcia-Molina V., Banos M.A., Gimenez J., Esplugas S. 2004, Applied Catalysis BEnvironmental 47, pp. 219-256. Pignatello J.J., Oliveros E., MacKay A. 2006, Crit. Rev. Environ. Sci. Technol. 36, pp. 1-84. Saputra E., Muhammad S., Sun H., Ang H.M., Tade M.O., Wang S. 2011, Red mud and fly ash supported Co catalyst for phenol oxidation, Catalyst Today (submitted). Shukla, P.R., Wang S., Ang H.M., Tade M.O. 2010, Photocatalytic oxidation of phenolic compounds using zinc oxide and sulphate radicals under artificial solar light. Separation and Purification Technology, 70(3): p. 338-344. Song W., Justice R.E., Jones C.A., Grassian V.H., Larsen S.C. 2004, Synthesis, Characterization, and adsorption Properties of Nanocrystalline ZSM-5, Langmuir, 20, pp. 8301-8306. Shukla P., Sun H.Q., Wang S.B., Ang H.M., Tade M.O. 2011, Separation and Purification Technology 77, pp. 230-236. Shukla P., Wang S.B., Singh K., Ang H.M., Tade M.O. 2010, Applied Catalysis B-Environmental 99, pp. 163-169. Shukla P.R., Wang S.B., Sun H.Q., Ang H.M., Tade M.O, 2010, Applied Catalysis BEnvironmental 100, pp. 529-534. Wang S. 2008, Dyes and Pigments 76, pp. 714-720. Yang, Q., Choi H., Al-Abed S.R., Dionysiou D.D. 2009, Applied Catalysis B-Environmental 88, pp. 462-469. Zhang W., Tay H.L., Lim S.S., Wang Y.S., Zhong Z.Y., Xu R. 2010, Applied Catalysis B Environmental 95, pp. 93-99.

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4. Draft academic paper 2: Analisis Pendapatan Petani Kelapa Sawit di Kabupaten Bireuen : Tinjauan Pengaruh Harga Eksport CPO terhadap Tanda Buah Segaar (TBS) (Ernawati, Syaifullah Muhammad, Izarul Machdar dan Sofyana) Teknologi Nanopartikel Meningkatkan Nilai Ekspor Crude Palm Oil (CPO) dan Tandan Buah Segar (TBS) Kelapa Sawit Indonesia 4,7 Trilyun

1)

Ernawati 1), Syaifullah Muhammad 2) Jurusan Eonomi Pembangunan Universitas Syiah Kuala 2) Jurusan Teknik Kimia Universitas Syiah Kuala

Abstrak Penelitian ini bertujuan melihat pengaruh harga Crude Palm Oil (CPO) terhadap harga Tandan Buah Segar (TBS) kelapa sawit yang secara langsung mempengaruhi pendapatan petani kelapa sawit Indonesia. Penelitian menggunakan data panel tahun 2014. Hasil penelitian menunjukan harga CPO signifikan mempengaruhi harga TBS kelapa sawit, juga memproyeksikan nilai ekspor CPO dan TBS kelapa sawit Indonesia meningkat 5,1 trilyun rupiah akibat intervensi nanozeolit. Implikasinya, diperlukan maksimalisasi strategi dalam penggunaan teknologi nanozeolit, guna meningkatkan harga CPO yang berdampak pada meningkatnya nilai ekspor CPO dan pendapatan petani kelapa sawit melalui kenaikan harga TBS. Keywords: harga CPO, harga TBS, Nanozeolit, ekspor CPO, pendapatan. Pendahuluan Kelapa Sawit merupakan salah satu komoditi andalan Sektor Pertanian yang berorientasi ekspor. Kebun dan industri kelapa sawit Indonesia telah menyerap lebih dari 4,5 juta petani dan tenaga kerja sekaligus menyumbang 4,5 persen dari nilai ekspor (Suharto, 2007). Kondisi ini ikut melatarbelakangi Indonesia sebagai salah satu negara pengekspor crude palm oil (CPO) terbesar di dunia. Grafik 1. Volume dan Nilai Ekspor CPO Indonesia (dalam 000 Ton dan US$)

Sumber: Direktorat Jenderal Perkebunan, 2012 (diolah). Perkembangan volume dan nilai ekspor CPO Indonesia terus mengalami peningkatan, seperti tampak pada grafik 1. Salah satu yang memicu peningkatan ini adalah tingginya permintaan CPO dunia terutama dari dua konsumen terbesar dunia, India dan China (Nainggolan 2007). Selain itu, pemanfaatan minyak sawit (CPO) sebagai bahan baku biodiesel juga menyebabkan permintaan

42

terhadap CPO semakin tinggi, yaitu terkait dengan pengunaan bahan bakar nabati sebagai dampak dari meningkatnya harga minyak bumi (CO, crude oil), terutama di tahun 2007 (Sugandi, 2008). Grafik 2. Perkembangan harga minyak nabati dan harga minyak bumi (brent) (2011-2013)

Sumber: Drajat (2014) Evaluasi tahun 2013 menurut Drajat (2014) mengindikasikan bahwa pergerakan harga selain ditentukan oleh faktor fundamental supply and demand, juga dipengaruhi oleh faktor kebijakan. Pertama, faktor fundamental iklim/cuaca. Faktor cuaca dan musim produksi pada periode tertentu dimana produksi CPO berkurang telah menimbulkan spekulasi peningkatan permintaan terhadap CPO dalam jangka pendek sehingga menaikkan harga CPO. Faktor fundamental kedua yaitu pertumbuhan ekonomi negara-negara pengimpor terutama Cina dan India yang diperkirakan meningkat dan mulai terjadi pemulihan krisis ekonomi Uni Eropa. Pada sisi kebijakan, faktor yang sangat mungkin mendorong kenaikan harga adalah kebijakan pengendalian ekspor CPO oleh Indonesia melalui penggunaan instrumen BK (bea keluar) yang progresif. Indonesia merupakan negara produsen CPO nomor satu di dunia. Kebijakan pengendalian ekspor yang berlaku efektif mengakibatkan berkurangnya pasokan CPO ke pasar global melalui aktivitas ekspor. Hal ini mendorong spekulasi permintaan terhadap CPO sehingga menaikkan harga CPO. Harga buah sawit atau dikenal dengan tandan buah segar (TBS) secara konsisten juga berkorelasi dengan harga CPO. Hal ini diantaranya disebabkan oleh penetapan harga TBS yang mengacu pada harga CPO. Peningkatan harga CPO dan TBS menunjukkan bahwa nilai harga yang diterima oleh petani sawit (harga TBS) semestinya sebanding dengan peningkatan harga CPO atau nilai harga yang didapat produsen CPO (Rachman 2005). Ada realitas di tingkat komoditas bahwa petani kelapa sawit berskala kecil umumnya tidak menikmati keuntungan dari melonjaknya harga CPO. Kebun-kebun sawit yang dikelola oleh rakyat hanya mampu untuk menjual kelapa sawit dalam bentuk TBS, yang harganya lebih sering dikendalikan oleh pedagang (Sugandi, 2008). Kondisi ini terjadi kemungkinan karena tidak adanya konsistensi menjalankan peraturan mengenai harga dasar atau harga pembelian minimum untuk TBS sawit di tingkat komunitas. Hal tersebut sangat memprihatinkan, semestinya pendapatan petani kelapa sawit ikut meningkat seiring dengan meningkatnya permintaan dan harga CPO. Deskripsi ini melatarbelakangi perlunya penelitian pengaruh harga CPO terhadap harga tandan buah segar yang secara langsung mempengaruhi pendapatan petani kelapa sawit Indonesia. Usaha tani dalam pelaksanaannya bertujuan untuk memperoleh pendapatan yang digunakan untuk memenuhi kebutuhan termasuk kegiatan diluar usahatani. Untuk memperoleh pendapatan pada tingkat yang diinginkan maka petani seharusnya mempertimbangkan harga jual produksi usahatani

43

dan melakukan perhitungan terhadap semua biaya usahataninya. Hal ini dilakukan agar tingkat efektivitas usahatani menjadi lebih tinggi (Kasmir, 2004). Simanjuntak (2004) juga mengatakan bahwa peningkatan pendapatan petani atau pengusaha pertanian dapat ditentukan oleh jumlah produksi yang dapat dihasilkan, harga penjualan produksi dan biaya produksi dari usaha tani. Jumlah produksi dari satu usaha tani atau satu perusahaan pertanian, ditentukan oleh skala usaha atau produktivitas yang dapat diperoleh satu unit usaha tani atau perusahaan pertanian. Usaha tani merupakan suatu kegiatan produksi, dimana peran faktor produksi sebagai input dalam menghasilkan output perlu menjadi perhatian utama (Amang, 1995). Variabel lahan dan tenaga kerja merupakan penggerak semua kegiatan dalam usaha tani. Efisiensi usaha tani secara umum diartikan sebagai hasil pekerjaan produktif yang dapat diselesaikan persatuan waktu tenaga kerja. Semakin tinggi efisiensi penggunaan tenaga kerja semakin tinggi pula pendapatan yang diterima dari usaha tani. Oleh sebab itu, efisiensi tenaga kerja berpengaruh pada pendapatan. Efisiensi penggunaan tenaga kerja yang dicapai suatu usaha tani dapat dipakai sebagai indikator keberhasilan usaha tani. Efisiensi usaha tani akan menekan biaya produksi sehingga meningkatkan pendapatan petani (Tjakrawiralaksana dan Soeritmaja, 1993). Intervensi teknologi dilakukan dalam rangka meningkatkan efisiensi dan nilai tambah produk. Teknologi merupakan salah satu variabel dari fungsi produksi yang berdampak tidak hanya pada kuantitas produk, tapi juga kualitas produk, yang pastinya berkorelasi positif terhadap harga produk. Variabel teknologi menjadi faktor pendorong yang memicu pertumbuhan ekonomi, seperti dalam model Solow (1956). Perumusan fungsi produksinya adalah Y = f(K, L), dimana pendapatan merupakan fungsi dari capital (K) dan labor (L). Labor disini adalah LXE dimana E merupakan efisiensi tenaga kerja, sehingga Y = f(K, LXE). Selanjutnya Y adalah Y/LE dimana LE menunjukkan jumlah tenaga kerja efektif. Pengaruh kemajuan teknologi terhadap perubahan modal dapat dirumuskan: Δk = sf(k) - (γ + n + g) kt, dimana g merupakan kemajuan teknologi melalui efisiensi tenaga kerja. Kemajuan teknologi meningkatkan pendapatan per tenaga kerja. Dampak kemajuan teknologi mendorong pertumbuhan ekonomi secara berkelanjutan karena mengoptimalkan efisiensi tenaga kerja yang terus tumbuh (Mankiw, 2008). Penelitian Drajat (2007) tentang alternatif strategi pengembangan ekspor minyak sawit menyimpulkan bahwa pemerintah sebagai regulator dan fasilitator ekspor sangat penting dalam pengembangan ekspor CPO. Dengan menggunakan pendekatan Analytical Hierarchy Process (AHP), ditunjukkan bahwa untuk mencapai tujuan yang diinginkan, aktor dalam pengembangan ekspor CPO perlu mengutamakan strategi pengembangan infrastruktur diikuti dengan optimalisasi sumber daya, pengembangan kelembagaan dan implementasi kebijakan. Hasil kajian sebelumnya (Dradjat, et. al, 2002) menunjukkan bahwa daya saing komoditas utama perkebunan Indonesia diperkirakan lebih rendah dari komoditas yang diproduksi negara pesaing. Rendahnya daya saing tersebut disebabkan kualitas produk yang ditawarkan masih dibawah kualitas produk negara pesaing. Kualitas produk secara langsung akan mempengaruhi harga produk. Oleh sebab itu, orientasi meningkatkan daya saing akan berdampak pada meningkatnya harga produk. Itu pula sebabnya persoalan daya saing ini juga menjadi fokus pemerintah dalam penyusunan kebijakan dan program pembangunan pemasaran hasil pertanian (Direktorat Jenderal Pengolahan dan Pemasaran Hasil Pertanian, 2006). Teknologi berperan penting dalam meningkatkan kualitas CPO Indonesia. Secara langsung hal ini akan mempengaruhi daya saing produk CPO Indonesia di tingkat dunia, sekaligus menambah besaran devisa karena kualitas produk pastinya berkorelasi positif terhadap harga. Salah satu bentuk intervensi teknologi dalam mendorong peningkatan harga CPO adalah dengan meningkatkan Deteration Of Bleachability Index (DOBI). DOBI adalah indeks derajat kepucatan minyak sawit mentah. DOBI merupakan rasio angka dari penyerapan Spektrofotometer pada λ 446 nm dan λ 269 nm. Metode ini dikembangkan oleh Dr. P.A.T. Swabada dari Institut Penelitian Minyak Sawit dari Malaysia (Malaysia Palm Oil Board).

44

Tabel 1. Relasi nilai DOBI dengan Kualitas CPO DOBI Indeks Kualitas < 1,68 Buruk 1,76 – 2,30

Kurang

2,36 – 2,92

Cukup

2,99 – 3,24 > 3,24

Baik Terbaik

Sumber : Buletin Infomutu Deptan, 2004 Pengukuran terhadap hal ini dilakukan dengan melarutkan minyak sawit ke dalam pelarut n-heksan dan menentukan penyerapannya dalam spektrofotometer Keck Seng menggunakan suatu alat spektrofotometer UV-Visible Hitachi U-2000. Hubungan DOBI indeks dan kualitas CPO seperti terlihat pada Tabel 1. Kenyataannya, rata-rata angka DOBI indeks CPO Indonesia adalah 2,8, sedangkan DOBI dengan kategori baik adalah 2,93–3,24 berdasarkan standar Codex Allimentariurs Commision. Kondisi ini menyebabkan harga CPO Indonesia di Pasar Internasional selalu mendapatkan pemotongan antara 300 500 rupiah per kilogram (Deptan, 2004). Teknologi dapat berperan memperbaiki kualitas lingkungan akibat pencemaran, juga untuk meningkatkan kuantitas dan kualitas produk. Laporan riset menampilkan efektivitas Activated Carbon dalam proses pengolahan limbah organik. Activated Carbon telah digunakan untuk degradasi berbagai pencemar organik tanpa perlu menambah fase aktif. Activated Carbon juga paling banyak digunakan untuk meyerap berbagai jenis bahan dalam dalam larutan termasuk sebagai bleaching agent dalam pengolahan CPO menjadi minyak makan (Muhammad, 2012). Selain Activated Carbon, zeolite merupakan material lainnya yang juga memiliki porositas dan luas permukaan yang besar dan banyak digunakan sebagai adsorbent dan katalis. Zeolit yang terdiri dari AlO4 dan SiO4 tetrahedral adalah kristal alminosilicate yang mengandung pori-pori dan rongga pada dimensi molekuler (Cundy dan Cox, 2004). Zeolit adalah adsorben dengan kapasitas tinggi dan selektif karena mampu memisahkan molekul berdasarkan ukuran dan konfigurasi molekul (Song dkk, 2004). Nanoteknologi adalah ilmu dan teknik pembuatan bahan, struktur fungsional, dan perangkat pada skala nanometer. Partikel ukuran nano seperti pada activated carbon dan zeolite akan memberikan sifat unik relatif terhadap partikel tersebut dengan ukuran konvensional. Penurunan ukuran partikel dengan skala nanometer ini menyebabkan perubahan substansial dalam sifat activated carbon ataupun zeolit yang membuat mereka menjadi material yang cukup menjanjikan untuk banyak aplikasi (Muhammad dkk, 2009). Penggunaan teknologi nano partikel seperti nano activated carbon dan nano zeolite akan mampu mengkoreksi sifat-sifat kimia-fisika dari CPO seperti warna, Deterioration of Bleachability Index (DOBI), bau, titik kekeruhan dan lain-lain agar dapat memenuhi standar internasional (Muhammad dkk, 2013). Gambar 1 memperlihatkan beberapa contoh nanozeolite. Hipotesis penelitian ini, harga Crude Palm Oil (CPO) berpengaruh positif terhadap harga Tandan Buah Segar (TBS) kelapa sawit. Penelitian ini juga memproyeksikan kenaikan nilai ekspor CPO dan Tandan Buah Segar (TBS) kelapa sawit akibat teknologi nanozeolit yang menaikkan DOBI indeks CPO.

45

Gambar 1. Beberapa contoh Nanozeolite

(Syaifullah Muhammad, 2009) Metode Jenis data yang digunakan dalam penelitian ini adalah data sukender, panel data harga Crude Palm Oil (CPO) dan harga TBS (Tandan Buah Segar) kelapa sawit tahun 2014. Proyeksi perubahan pendapatan ekspor CPO dan Tandan Buah Segar (TBS) kelapa sawit menggunakan pendekatan data ekspor CPO dan produksi kelapa sawit tahun 2013 dan asumsi kenaikan DOBI indeks CPO akibat intervensi nanozeolit. Penelitian ini menggunakan model linear. Harga CPO fungsi dari harga ekspor CPO dan Harga Tandan buah Segar (TBS) kelapa sawit fungsi dari harga CPO. Penulisan model untuk hubungan ini: PCPO = α0 + β1 PECPO + ε (1) PTBS = γ0 + θ1 PCPO + ε (2) Disini: PCPO = Harga Crude Palm Oil PECPO = Harga ekspor Crude Palm Oil PTBS = Harga Tandan Buah Segar kelapa sawit α0, γ0 = Konstanta β1, θ1 = Parameter yang dicari ε = error Untuk menganalisis besarnya perubahan pendapatan petani kelapa sawit dan penerimaan ekspor CPO akibat perubahan harga ekspor CPO dan harga Harga Tandan Buah Segar kelapa sawit, digunakan persamaan (3) dan (4) berikut ini: ∆YE = VE x ∆PECPO (3) ∆YT = Q x ∆PTBS (4) Disini: ∆YE = Proyeksi perubahan penerimaan ekspor CPO VE = Volume ekspor CPO ∆PECPO = Perubahan harga ekspor CPO ∆YT = Proyeksi perubahan pendapatan usahatani kelapa sawit Q = Produksi kelapa sawit ∆PTBS = Perubahan harga TBS kelapa sawit Penelitian menggunakan panel data 7 propinsi penghasil kelapa sawit besar di Indonesia, dari bulan Januari sampai bulan September tahun 2014. Harga TBS yang digunakan adalah rata-rata harga tandan buah segar kelapa sawit pada umur tanaman 3 tahun sampai umur tanaman diatas 10 tahun. Harga CPO adalah harga penjualan CPO dalam negeri. Volume ekspor dan produksi adalah jumlah ekspor CPO dan produksi kelapa sawit Indonesia, keduanya menggunakan pendekatan data tahun 2013.

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Hasil Penelitian Berdasarkan hasil perhitungan statistik didapatkan hasil regresi sebagai berikut:

Variabel Dependent

Tabel 2. Hasil Estimasi Harga Ekspor CPO terhadap harga CPO dan harga CPO terhadap harga TBS kelapa sawit Variabel P-Value Koefisien Std. Error T.Rasio independen PECPO

0.53623

Konstanta

3681.2

PCPO

0.22274

Harga CPO Harga TBS kelapa sawit

Konstanta Sumber: Data Primer, 2014 (diolah)

0.4561E01 402.1 0.1999E01 168.0

-212.36

11.76

0.000

9.156

0.000

11.14

0.000

-1.264

0.211

Hasil estimasi menunjukkan harga ekspor CPO signifikan mempengaruhi harga CPO dengan koefisien 0,54. Estimasi terhadap harga CPO juga signifikan mempengaruhi harga TBS kelapa sawit dengan nilai koefisien 0,22. Hasil ini mengindikasi bahwa jika harga ekspor CPO naik sebesar Rp.100,-, maka dapat mengakibatkan kenaikan sebesar Rp.54,- pada harga CPO. Rata-rata kenaikan harga ekspor CPO naik Rp. 400,- akibat tercapainya DOBI indeks di atas 2,93. Pencapain DOBI indeks sesuai standar internasional ini dimungkinkan akibat pengaruh intervensi nanozeolit dalam mengadsorbsi warna CPO menjadi lebih pucat. Hasil uji laboratorium terhadap hal ini telah dilakukan (Muhammad, dkk, 2014). Kenaikan harga ekspor ini ikut menaikkan harga CPO sebesar Rp. 216,- per kg, akibatnya akan terjadi perubahan pada harga TBS kelapa sawit yaitu naik sebesar Rp. 47,52,- per kg. Secara empiris harga rata-rata TBS kelapa sawit menujukkan perbedaan pada tingkat umur tanaman yang berbeda (Grafik 3). Grafik 3. Harga Rata-rata TBS Kelapa Sawit Indonesia Pada Umur Tanaman 3 s.d 10 thn >, Periode Januari – September 2014 2,000 1,900 1,800

1,855 1,808

1,878 1,831 1,789

1,768 1,700 1,675 1,600

1,626

1,500

1,545

1,400

1,439

1,958 1,907

1,938 1,907

1,869

1,823

1,812

1,768 1,696 1,646 1,563

1,726

1,715 1,600

1,630 1,518

1,502

1,455

1,479

1,450 1,406 1,340

1,300

1,200

1,200

3 years 7 years

1,100

4 years 8 years

5 years 9 years

6 years 10 years >

1,000

Jan

Feb

Mar

Apr

May

Sumber : Media sawit@com. (2014, Diolah)

47

June

July

Aug

Sept

Tingkat harga rata-rata TBS kelapa sawit pada umur tanaman diatas 10 tahun adalah Rp. 1.832,42,-, sedangkan harga rata-rata pada umur tanaman 3 tahun Rp. 1.425,38,-. Adanya selisih harga Rp. 407,04,- ini disebabkan perbedaan kualitas TBS kelapa sawit pada tingkat umur tanaman yang berbeda, sehingga mempengaruhi kualitas CPO yang dihasilkan. Faktor ini juga diperkirakan mempengaruhi indeks derajat kepucatan minyak sawit mentah (DOBI). Perbedaan harga ini menjelaskan bahwa kualitas produk secara langsung mempengaruhi harga jual. Harga rata-rata TBS kelapa sawit tahun 2014 berfluktuasi dan cenderung menurun mulai April sampai September 2014. Hal ini terutama disebabkan isu-isu luar negeri terhadap tanaman kelapa sawit yang tidak ramah lingkungan. Dalam Roundtable Discussion on Sustainable Palm Oil di Den Haag, 12 September 2013, Duta Besar RI untuk Belanda, Retno Marsudi menyampaikan bahwa isu-isu negatif terkait environmental sustainability yang terus menerus dikembangkan di eropa tentang CPO sangat merugikan Indonesia sebagai salah satu negara produsen sawit dan CPO terbesar di dunia (http://swa.co.id & http://pontianak.tribunnews.com). Meskipun terjadi penurunan harga ratarata TBS kelapa sawit, namun perbedaan harga pada tingkat umur tanaman tetap dirasakan, seperti terlihat pada grafik 3. Kondisi tersebut mengindikasi adanya hubungan positif kualitas dan harga. Hubungan positif juga terjadi antara harga ekspor CPO, harga CPO dalam negeri dan harga TBS Kelapa Sawit ditingkat komunitas, diperlihatkan grafik 4 berikut ini: Grafik 4. Harga TBS Kelapa Sawit dan CPO (IDR) dan Harga Ekspor CPO (US$) Tahun 2014 10000 9000 8000 7000 6000

Harga CPO

5000

Harga TBS

4000

Harga Ekspor CPO

3000 2000 1000 0

Sumber : Media sawit@com. (2014, Diolah) Tabel 3. Perubahan Nilai Ekspor CPO dan TBS Kelapa Sawit Indonesia Variabel Ekspor CPO TBS kelapa sawit

Produk (000 Ton) 8480 27500

∆Harga per kg (Rp) 400 47,52

∆Pendapatan (Rp) 3,4 Trilyun 1,3 Trilyun

Sumber : Media sawit@com. (2014, Diolah) Berdasarkan data yang diolah Gabungan Asosiasi Pengusaha Kelapa Sawit Indonesia (GAPKI), volume ekspor CPO beserta produk turunannya pada tahun 2013 mencapai 21,2 juta ton. Jumlah tersebut 40% diantaranya yaitu 8.480.000 ton adalah CPO yang belum diolah. Perhitungan terhadap perubahan harga ekspor CPO akibat intervensi nanozeolit dapat meningkatkan penerimaan ekspor CPO 3,4 trilyun rupiah. Intervensi teknologi sekaligus akan meningkatkan penerimaan petani dari hasil usahatani kelapa sawit. Proyeksi terhadap hal ini dilakukan dengan menghitung kenaikan

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harga CPO akibat pengaruh teknologi. Hasil regresi antar variabel independen dan variabel dependen memperlihatkan bahwa harga ekspor CPO berkorelasi positif terhadap harga CPO dalam negeri. Korelasi yang sama juga terjadi pada perubahan harga TBS kelapa sawit akibat pengaruh perubahan harga CPO, masing masing pada koefisien estimasi 0,54 dan 0,22 seperti diperlihatkan tabel 2. Dengan menggunakan data produksi kelapa sawit tahun 2013, nilai estimasi tersebut dapat berdampak pada peningkatan pendapatan usahatani kelapa sawit Indonesia sebesar Rp. 1,3 trilyun (Tabel 3), sehingga intervensi nanozeolit meningkatkan nilai ekspor crude palm oil (CPO) dan tandan buah segar (TBS) kelapa sawit Indonesia 4,7 trilyun. Kesimpulan Nanopatikel teknologi yang diterapkan untuk peningkatan kualitas CPO khususnya peningkatan nilai DOBI telah meningkatkan nilai tambah bagi industri CPO Indonesia. Hasil penelitian menunjukkan harga ekspor crude palm oil (CPO) signifikan mempengaruhi harga crude palm oil (CPO) dan harga crude palm oil (CPO) signifikan mempengaruhi harga tandan buah segar (TBS) kelapa sawit, dengan koefisien estimasi masing–masing 0,54 dan 0,22. Didasarkan hasil estimasi ini, perubahan nilai ekspor CPO dan perubahan pendapatan usahatani kelapa sawit diperhitungkan sebesar 4,7 trilyun rupiah. Rekomendasi penelitian ini adalah, perlunya maksimalisasi strategi agar inovasi teknologi nanozeolit untuk menaikkan DOBI indek dapat diaktualkan sehingga berdampak pada meningkatnya harga CPO dalam negeri dan pendapatan petani kelapa sawit melalui pengingkatan harga TBS kelapa sawit. Ucapan Terima Kasih Terima kasih disampaikan kepada Project Penelitian Master Plan Percepatan dan Perluasan Pembangunan Ekonomi Indonesia (MP3EI) 2014 dari Direktorat Pendidikan Tinggi (DIKTI) yang telah membiayai penelitian ini. Referensi Almasdi Syahza., 2002. Potensi Pembangunan Industri Hilir Kelapa Sawit di Daerah Riau, dalam Usahawan Indonesia, No. 04/TH XXXI April 2002. Almasdi Syahza, dkk, 2004, Kelapa sawit: pengaruhnya terhadap Ekonomi regional daerah Riau. Lembaga Penelitian Universitas Riau. Buletin Infomutu Deptan, edisi Mei 2004, halaman 1 dan 7. Cundy C.S., Cox P.A. 2004, The hydrothermal synthesis of zeolites: History and development from the Earliest to the present time, Chem. Rev.103, pp. 663-701. Direktorat Jenderal Pengolahan dan Pemasaran Hasil Pertanian. 2001. Kebijakan dan Program Pengolahan dan Pemasaran Hasil Pertanian 2001-2004. Direktorat Jenderal Pengolahan dan Pemasaran Hasil Pertanian, Jakarta. Dradjat, B, 2014. Harga CPO: Review Harga 2013 dan Prospek, 2014, PT Riset Perkebunan Nusantara, at http://www.pustakadunia.com. Dradjat, B, dan Bustomi, H, 2009. Alternatif Strategi pengembangan Ekspor Minyak Sawit Indonesia. Jurnal Manajemen & Agribisnis, Vol. 6 No. 1 Maret 2009. Dradjat,B, 2002. Prospek Ekspor Produk Perkebunan: Implikasi Strategis bagi Indonesia. Makalah disajikan pada seminar Penerapan Otonomi Daerah dan Daya Saing Agribisnis Perkebunan. Diselenggarakan oleh Lembaga Riset Perkebunan Indonesia, Bandung, 26-27 Juni, 2002. Irawan, Andi, 1997. Kebijakan Harga dan Keberlanjutan Produksi. Ekonomi dan Keuangan Indonesia, vol. XLV N0.4, LPEM FE- UI. Jakarta. Lembaga Manajemen FE UI, Jakarta Badan Pusat Statistik, 2012. Laporan Perekonomian Indonesia. BPS Pusat. Jakarta. Muhammad, S., Edy Saputra, Hongqi Sun, H.M. Ang, Moses O. Tade, Shaobin Wang, Removal of Phenol Using Sulphate Radicals Activated by Natural Zeolite-Supported Cobalt Catalysts, Journal of Water, Air, & Soil Pollution, November 2013, 224:1721.

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Muhammad, S., Shukla, P.R., Tade, M.O. and Wang, S. (2012). Heterogeneous activation of peroxymonosulphate by supported ruthenium catalysts for phenol degradation in water, Journal of Hazardous Materials, 215-216, 183-190. Syaifullah Muhammad, Izarul Machdar, Yunardi, Shaobin Wang, Moses O. tade, Chromium and Lead Removal Using Synthesized Nanocristalline Zeolite, Jurnal Purifikasi, Vol. 10, No.1 Juli 2009, 49-58 Saragih, Bungaran, 2001, Agribisnis: Paradigma Baru Pembangunan Ekonomi Berbasis Pertanian, PT Loji Grafika Griya Sarana, Bogor. Badan Pusat Statistik, Statistik Indonesia, 2012. Http://www.pustakadunia.com. http://[email protected]. http://swa.co.id & http://pontianak. tribunnews.com.

5. Draft Buku Ajar Nanopartikel Teknologi

CHAPTER ONE INTRODUCTION 1.1 The nature and use of zeolites Nanotechnology has generated much interest in the scientific community, and it has become a very active area of research. Nanotechnology is the science and engineering of creating materials, functional structures, and devices on nanometer scale. Nano size particles such as nano crystalline zeolites have unique properties relative to conventional micrometer sized zeolite crystals. The reduction of particle size to the nanometer scale leads to substantial changes in properties of zeolite which make them as promising materials for many applications. Zeolites were firstly identified in 1756 by Freiherr Axel Frederick Cronstedt, a Swedish mineralogist who discovered natural zeolites of stilbite (Malherbe, 2007). Zeolites (consisted of corner-sharing AlO4 and SiO4 tetrahedral) are crystalline alminosilicate containing pores and cavities of molecular dimension. Many of them can be found as natural minerals but synthetic zeolites are the most widely used. Zeolite crystals are also porous on a molecular scale, their structures revealing regular array of channels and cavities, creating a nano scale labyrinth which can be filled with water or other guest molecules. The resulting molecular sieving ability has enabled the creation of new types of selective separation processes such as ion exchange and sorption. Figure 1 shows the structures and morphology of representative of ZSM-5.

Figure 1 Zeolite ZSM-5 structures: (A) Part of ZSM-5 structure, (B) Crystal morphology of ZSM-5(Cundy & Cox, 2004) Zeolites are one of the most important heterogeneous acid catalysts used in industry. Their key properties are size and shape selectivity, together with the potential for strong acidity. Zeolites also have ion exchangeable sites and highly hydrothermal stability. Table 1 depicts some physical and chemical properties of natural zeolite.

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Table 1 Physical and chemical properties of natural zeolite Physical Properties Specific Gravity (g/cc), 2.4 Surface Area(m2/g), 107 Pore size, 3.55-9.45 Color, Off-white/pale green Water Absortion (gram per 100 grams), 20 % - 30 % Bulk/Density (lb/cuft), - loose 66 lbs - Trapped 71 lbs Electrical Conductivity (cm/hr), 13.9

Chemical Properties SiO2, 65.8 % Fe2O3, 2.6 % CaO, 3.4 % MgO, 1.3 % Al2O3, 14.3 % K2O, 2.7 % MnO, 0.04 % TiO2, 0.3 % BaSO4, 0.9 % Na2O, 2.5 % Loss of Ignition, 5.7 % pH value, 8.1

1.2 Types of zeolite framework The zeolite framework is defined as corner sharing network of tetrahedreally coordinated atoms. Zeolite framework does not depend on composition, distribution of the T-atoms, cell dimension or symmetry. Framework type code is usually derived from the name of the type materials. For instance, LTA, FAU, BEA and SOD are derived from linde type A, faujasite, beta and sodalite, repectively. Figure 2 and Table 2 show several types of framework and type codes (FTC) of zeolites.

Figure 2. Representative of Zeolites Framework, (A) LTL, (B) BEA, (C) MEL (http://www.iza-stucture.org, retrieved: 10 August 2007) Table 2 Zeolite framework type code (FTC) Zeolite FTC Zeolite Stilbite STI ZK-5 Faujasite FAU Na-P1 Linde Type A (Zeolite A) LTA Sigma-2 Linde Type X (Zeolite X) FAU Mordenite Linde Type L (Zeolite L) LTL AIPO-5 Zeolite Y FAU AIPO-18 Silicate-1 MFI MCM-9 Silicate-2 MEL MCM-35 ZSM-5 MFI Sodalite ZSM-11 MEL Offretite Beta BEA Theta-1 (http://www.iza-stucture.org, retrieved: 10 August 2007)

FTC KFI GIS SGT MOR AFI AEI VFI MTF SOD OFF TON

1.3 Development of nano zeolite synthesis Nanozeolites are crystalline porous aluminosilicates with molecular dimension in the range of 10-1000 nm of the particle size (Mintova, 2003). Nanozeoilites have higher external surface area and reduced diffusion path lengths due

51

to smaller particle size. Many nanozeolite crystals have been successfully synthesized by researchers. For instance, low and intermediate Si/Al ratios of zeolites such as types of LTA, FAU, SOD, GIS, OFF, MOR and ZSM-2, high Si/Al ratios of zeolites such as BEA and MFI, silica molecular sieves (types of MFI and MEL), titanosilicates and aluminophosphates (types of MFI, AFI, AEL, and AEI) have been reported (Tosheva and Valchev, 2005). Mintova (2003) reported the synthesis of nano size zeolites including nanozeolite A (LTA), nanozeolite Y (FAU), nanozeolite silicate-1 (MFI) and nanozeolite beta (BEA) at temperatures lower than 100 0C with synthesis time up to 400 hours. The successful synthesis of nanozeolite A was also reported by Rakoczy and Traa (2003) who synthesized the materials at temperature of 800C with initial Si/Al ratios of 3.05, 4.03, 5.03, 6.99 and 7.89 and particle sizes in the range of 50-100 nm. Further, by adding tetramethylammonium bromide (TMABr) as a second source of organic template to the normal tetramethylammonium hydroxide (TMAOH), Holmberg et al. (2003) reported the synthesis of crystal sizes less than 32 nm of nanozeolite Y while simultaneously increasing the yield. The other researchers Persson et al (1994) reported the success of nanozeolite silicate-1 synthesis with average particle size of less than 100 nm at temperature of 155 0C in 29 hours. Crystalline zeolites are usually synthesized at high temperature. However, the 55 nm particle size of nanozeolite silicate-1 was synthesized by Corkery and Ninham (1997) at low temperature of 350C despite taking very long time of 40 months. Moreover, Grieken et al (2000) reported the synthesis of nanocrystalline ZSM-5 at 1700C for 24 hours with 10-100 nm particle sizes. The initial SiO2/Al2O3 of molar ratio used in the synthesis process is 60. With the similar procedure to Grieken et al, Song et al (2004) synthesized nanocrystalline ZSM-5 at temperature of 1650C with Si/Al ratio of 20. The obtained ZSM-5 particles were 15-60 nm for 120 hours synthesis time. Many other researchers reported the success of nanozeolite synthesis which indicate the interesting and promising prospect of nanozeolite technology (Tosheva & Valtchev, 2005) 1.4 Application of zeolite nanocrystal It is well known that zeolites have been used for many applications. In the last decade particularly for nano size zeolites, several applications can be found in the research reports. For instance, it was reported that nanozeolites could be used in medical diagnostic, particularly in magnetic resonance imaging (MRI). The study revealed the potential of Gd3+ loaded NaY nanocrystals which have higher relaxivity than that of micrometer sized zeolite crystals ((Tosheva & Valtchev, 2005) Further, because of their higher surface area and porosity, nanocrystalline zeolites are promising catalyst and adsorbent materials. They can be assembled into thin film and other porous nanostuctures for use as separation membranes, chemical sensor and photochemical hosts (Song et al, 2004). One of the major applications of colloidal zeolites is the preparation of supported zeolite films and membranes. Similar to that, it was reported that nanocrystalline zeolites particularly colloidal zeolite suspensions are very suitable for the preparation of structured material (Nalwa, 2002). According to adsorption test, nano structured zeolites have a high integrity of the shell layer which covers 86% of core crystals after a single step synthesis and 99% after a triple step synthesis. Moreover, all structured zeolites and micro/mesoporous materials were synthesized and prepared by utilization of zeolites nanocrystals or their precursor. Another application of zeolites nanocrystal is in separation process such as adsorption in particular the heavy metal removal which is the focus of this research and will be further elaborated. 1.5 Heavy metal removal Heavy metal ions are one of the most important pollutants in water, waste water and any other environmental sources. The environment regulation in many countries makes it necessary to develop various technologies for heavy metal removal. Many methods such as precipitation, electro deposition, membrane separation and adsorption have been used to tackle the problem. Precipitation is the most economic but is not efficient for dilute solution. Electro deposition and membrane separation are generally effective but high maintenance and operation cost. Adsorption is one of the few promising alternatives for this purpose due to an efficient process for heavy metal removal of adsorption especially using low cost natural adsorbent such as agricultural wastes, clay material, biomass, seafood processing wastes and zeolite (Kocaoba et al, 2007). As mentioned above, zeolites are widely used for many applications such as separations, catalysis, ion exchange and adsorption. It is accepted that zeolite which has porous structure is an effective heavy metal adsorbent. The fact is that zeolites possess exchangeable ions making them particularly suitable for removing heavy metal ions from industrial

52

effluent waters (Erdem et al, 2004). By using natural zeolite (clinoplitolite) at a certain pH and temperature, Inglezakis et al (2007) found that the removal efficiency of lead (Pb 2+) could be up to 55%. On the other hand, the discovery of synthetic zeolites has broadened immensely the available range of adsorbent and has led to an enormous upsurge in the development of adsorption process (Dabrowski et al, 2001). Basalldella et al (2007) for example, mentioned that synthetic zeolite A (LTA) is an effective adsorbent for chromium removal. Terdkiatburana et al (2007) reported that adsorption capacity of Pb 2+ on synthetic zeolite MCM-22 was higher than activated carbon. Many other researchers reported similar result in adsorption process using synthetic zeolites. Nevertheless, nano scale zeolite for heavy metal removal has been less developed. In the adsorption processes, two things are generally concerned: first, how much of pollutant can be loaded on to an adsorbent, and second, how long it will take for this loading. The answer is coming from the determination of the equilibrium parameters. These are the most critical parameters, since they determine whether the process is feasible or not. Laboratory experiments are usually performed to study the equilibrium condition. One of the most important factors affecting adsorption capacity and efficiency is surface area and the distribution of the area (Slejko, 1985). This fact makes nano size particles such as nanozeolites very reasonable to be considered in heavy metal adsorption process due to their large surface area. Xu et al (2005) for example, reported that nano-tin/NaY zeolite composite material had the perfect channel system of adsorption behavior. 1.6 Objectives and contributions of this study The main objective of the research is to synthesis several types of nanocrystalline zeolites such as nanozeolite A (LTA), nanozeolite Y (FAU), nanozeolite silicate-1 (MFI) and nanozeolite ZSM-5 (MFI). The synthesized nanozeolite products were then used in heavy metal removal. The specific objectives can be listed as follows: 1.

To provide an understanding of synthesis and crystallization mechanism of nanozeolite A, nanozeolite Y, nanozeolite silicate-1 and nanozeolite ZSM-5. 2. To develop optimal conditions of nanozeolite synthesis such as temperature, time, initial Si/Al ratio and other appropriate reactants ratio to obtain higher product in the range of nano size. 3. To apply the products of nanocrystalline zeolites in heavy metal adsorption and investigate several parameters such as adsorption capacities, adsorption efficiencies, adsorption isotherm and adsorption kinetics. 4. To investigate the effect of adsorption condition such as time, temperature, initial concentration, initial Si/Al ratio and particle size in adsorption process. This research would make a contribution to the development of nano material science particularly nanocrystalline zeolites. In general, the previous research in nanocrystalline zeolites often resulted in low product yields and long synthesis time. Hopefully, the quality and quantity of nanocrystalline zeolite can be improved in this research. Further, by testing the product in heavy metal adsorption, better understanding in this area can be pursued. It is known that heavy metals are usually found as pollutants in water, waste water, air, natural gas and any other environment resources. Therefore, the results would also contribute to improve the quality of the environment.

CHAPTER TWO LITERATURE REVIEW 2.1 Zeolite nanocrystal synthesis Various methods have been reported in the literature for zeolite synthesis. There are three steps in nanozeolite synthesis i.e. induction, nucleation and crystallization. Nucleation is the step where germ nuclei are obtained from very small aggregates of precursor and become larger with the time. Crystallization is initiated with engaging the germ nuclei from the nucleation step and other components of the reaction mixture. This process is influenced by several factors which can be modified during the synthesis procedure. These factors are the presence of cations in the reaction solution, OH- concentration, SiO2/Al2O3 ratio, H2O content, temperature, pH, time, aging, stirring of the reaction mixture, order of mixing and other factors (Malherbe, 2007). Tosheva and Valtchev (2005) reviewed that nanozeolite crystals can be synthesized from clear solution or gel system and also by confined space synthesis method. Figure 3 describes the scheme of the confine-space syntheses of zeolite nanocrystals.

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Figure 3. Scheme of the confine-space syntheses of zeolites nanocrystals (Tosheva and Valtchev, 2005)

Zeolite nanocrystals are usually synthesized under hyhrothermal condition using clear aluminosilicate solution, usually in the presence of organic compounds as templates such as tetramethylammonium (TMA) and tetrapropylammonium (TPA) (Zhan, et al. 2001). Further, Cundy and Cox (2004) reported aluminosilicate zeolites synthesized under hydrothermal condition from reactive gels in alkaline media at temperature of about 800C and 2000C and most high Si/Al ratio of zeolites (>10) are synthesized using organic templates, which have to be removed from the zeolites structure by calcinations. However, Corkery and Ninham (1997) synthesized nano crystal of silicate1 at low temperature of 350C and 1 atmosphere pressure despite very long synthesis time of about 40 months. According to this report, precipitated silica nanocrystal entered to the solution through slow depolymerization. Many other researchers reported the success of zeolite nanocrystal synthesis. The main concept of nanozeolite synthesis is to terminate the synthesis process while the zeolite crystals are still in the nano size range and to prohibit further crystal growth. Base on this concept, nanozeolites should be synthesized at low temperatures and ambient pressure. Unfortunately, low temperature in this process will result in low product yield and long synthesis time. However, Song et al. (2005) reported a method achieving high yield for nanocrystalline zeolite synthesis by periodically removing nanocrystal from synthesis solution and recycling unused chemicals including organic template. Table 3 depicts several synthesized zeolite nano crystals including molecular sieve type, molar composition, synthesis temperature and crystal size. Table 3. Representative of synthesized nanocrystalline zeolites (Tosheva & Valtchev, 2005) Type

Molar Composition

LTA

2.0-2.3(TMA)2O : 0.2-0.5Na2O : AI2O3 : 3.4SiO2 : 370H2O 6.1-15.8SiO2 : AI2O3 : 17Na2O :0.9-6.5(TMA)2O : 389H2O : 3iPrO2 0.3Na2O: 11.25SiO2 : 1.8AI2O3 : 13.4(TMA)2O : 700H2O 0 .22NazO:5.0SiO,:AI,0): 8.0(TMAlzO:400H,O (S) 2.46(TMA)2O : 0.032-0.43Na2O : 1.0 Al2O3 : 3.4SiO2:370H2O : 13.6 EtOH 0.15Na2O : 5.5(TMA)2O: 2.3AI2O3 : 10SiO2 :570H2O AI2O3 :4.35SiO2 : 1.40-3.13(TMA)2O(20H-):0-2.4(TMA)2O(2Br) : 0.048 Na2O : 249H2O 1.576(TMA)2O : 0.044Na2O : AI2O3:3.62SiO2 : 246H2O 0/0.53Na2O :0.62-1.52(TPA)2O: 10Si02 : 60/143H20 9TPAOH : 0/0.1 Na2O: 25Si02 : 480/1500H2O: 100EtOH 9TPAOH : 0.16Na2O : 1Al2O3 : 50Si : 300-495 H2O : 1/100EtOH Al2O3 : 60SiO2 : 11TPAOH : 900H2O 0.48Na2O : 9TEAOH : 0.25Al2O3 : 25SiO2 :295H2O SiO2 : 0.2(TEA)2O : 11.8H2O

FAU

MFI

BEA

54

Temp (0C) 100

Crystal size (nm) 230-240

80

50-100

22 63

40-80 130

100,130

75-137

100

40-80

100

32-120

100 50,60,80 98

100 25-80 95-180

165

15-60

70, 90 100 100

10-20 60 100

GIS SOD

1AI2O3 :4.17SiO2 :2.39(TMA)2O : 253H2O (S) 14(TMA)2O : 0.85Na2O : 1.0AI203 :40SiO2 : 805H2O

100 100

30-50 37

2.1.1 Structure of LTA, FAU and MFI It is commonly known that zeolite has specific framework depending on its type of the material. The framework or corner sharing network coordinated of tetrahedral atom enable zeolite growing up to be a bigger crystal. Based on the pore size, LTA, FAU and MFI types of zeolites are part of micro-porous materials because they have pore opening less than 20Å compared with meso-porous and macro-porous materials which have the pore opening of 20-500 Å and more than 500 Å, respectively. Specifically, LTA, FAU and MFI have channel dimension <100>8 4.1x4.1***, <111>12 7.4x7.4*** and {[100]10 5.1x5.5 ↔ [010]10 5.3 x 5.6} ***, respectively. (http://www.iza-stucture.org, retrieve: 10 August 2007). All of these zeolites have three dimensions of the channel which is indicated with three numbers of asterisks and also the bold numbers indicating number of T-atoms. Further, at MFI channel dimension it can also be seen the presence of double arrow which indicates the interconnecting channel system. Figure 4 shows the description of zeolite framework and channel dimension of LTA, FAU and MFI.

Figure 4. Zeolite framework and channel dimension (pore opening), (A) LTA, (B) FAU and (C) MFI (http://www.iza-stucture.org, retrieved: 10 August 2007)

2.1.2 Crystallization mechanism Understanding of crystallization mechanism is very important regarding the effectiveness and the efficiency of crystallization process and also important to determine the appropriate method in synthesis process of nanocrystalline zeolites. Mintova et al (1999) reported the crystallization mechanism of LTA nano crystal. The synthesis solution containing aluminosilicate with the average particle size of 5 nm is quickly agglomerated by adding the organic template until the amorphous aggregates with the particle size of 40-80 nm obtained. In the amorphous aggregates, the LTA is nucleated at room temperature within 3 days. In that system, only one single crystal in each amorphous gel particle was detected, therefore aggregation of several nuclei is not needed in the crystallization process. It was suggested that high super-saturation within gel particles, possibly coupled with pre-organization at interface of the amorphous network with occluded solution, is the driving forces for nucleation. The amorphous gel zeolite particles kept their average size over the route of the complete conversion into zeolite A and mass transfer from the solution

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supplies some of precursor material. Solution mass transfer has to be the main mechanism for the important crystal growth in the same zeolite A suspension at higher temperature. Figure 5 describes the LTA crystallization mechanism proposed by Mintova et al.

Figure 5. A schematic representation of the proposed zeolite A (LTA) growth mechanism (Mintova et al, 1999) On the other hand, the zeolite Y (FAU) crystallization mechanism is different from zeolite A. Valtchev et al (2005) described the mechanism as shown in Figure 6. Briefly, the mechanism is started from the system which reaches specific critical level of chemical evolution prior to the onset of crystallization. Further, the first stage of crystallization (10-15% crystallinity) begins where the crystal grows with propagation through the gel phase. The next step is the second stage of crystallization which is spontaneous aggregation of nanoparticles around crystallization center followed by an Ostwald ripening. The mechanism results in 100-300 nm aggregates of zeolite Y nano particles with the average particle size of 10-20 nm. This mechanism is different from LTA where the gel contains only one crystal in the aggregates. The zeolite Y nanocrystal is growing up from 40-50 particle sizes.

Figure 6. Schematic illustration of the crystallization of FAU-type zeolites (Valtchev et al, 2005) Another different crystallization mechanism is found for synthesis of silicate-1 nanocrystal as shown in Figure 7. According to the review by Tosheva and Valtchev (2005), in the ambient condition, the poly-condensation results in the crystal species formation containing 33 of Si atoms. The formation is the interaction with TPA cations until the feature of similar to MFI framework which is called nanoslabs with size of 1.3 x 4 x 4 nm is obtained. Until this stage, all of the process can be occurred at room temperature. But according to this model, a further aggregation forming the nanoblock should be occurring at higher temperature. The crystals then grow up to bigger size of the particle following the increase of crystallization temperature and time.

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Figure 7. Proposed mechanism of (A) nanoslab formation and (B) silicate-1 (MFI) crystal growth by aggregation nanoslabs (Kirschhock et al, 2000) Moreover, the crystallization mechanism of ZSM-5 was reported by Grieken et al (2000). The concise steps, ZSM-5 crystals are formed in two stages. First stage is based on solid-solid transformation of amorphous solid contained in homogeneous supersaturated solution. This amorphous solid is then becoming agglomeration and zeolitization until obtaining of the nanocrystalline ZSM-5. On the other hand, in the second stage, the initial solution which is less saturated in silicon and aluminium due to their consumption in the first stage, has nucleation process and transformed into nanocrystalline zeolite. The second stage is running slowly compared with the first stage. Description of ZSM-5 crystallization mechanism is shown in the following Figure 8. .

Figure 8. Scheme of ZSM-5 crystallization mechanism (Grieken et al, 2000) 2.1.3 Zeolite nanocrystal characterization The crystal size distribution are often obtained by at least two characterization techniques after separated from the solution by repeated high speed centrifugation. One gives the average particle size such as dynamic light scattering (DLS) and X-ray diffraction (XRD) from the XRD peak broadening using the Scherrer’s equation and another one describes visual measurement of particle size such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

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Figure 9. XRD and SEM characterization of zeolite A, zeolite Y, silicate-1 and ZSM-5 nanocrystals (Zhu et al, 1998, Shcoeman et al, 1994, Persson et al, 1994 and Grieken et al, 2000) X-Ray powder diffraction techniques are used to recognize a sample of solid material by comparison of the position of diffraction lines and their intensities with a large data base. Powder diffraction data are also used to determine phase diagram, for different solid phases result in different diffraction patterns, and to determine the relative amounts of each phase present in a mixture (Atkins, 1998). On the other hand, SEM provides visual image of a limited number of the representative particles which also give approximately visual particle sizes. The ability of the SEM is to combine high magnification and an impressive depth. Further, the measurement of SEM image through image calibration by using the image processing computer software can also give the average crystal size of the particles. Figure 9 shows the XRD pattern and SEM of zeolites A, zeolite Y, silicate-1 and ZSM-5, which demonstrates the morphology of the crystals. 2.1.4 Synthesis of zeolite A (LTA) nanocrystal It has been developed in terms of hydrothermal conditions to produce nanozeolite A (LTA Channel dimension: <100>8 4.1 x4.1 Å***, Mintova, 2003), which was identified as crystal alumina silicate within a low and intermediate ratio of Si/Al (Tosheva & Valchev, 2005). Rakoczy & Traa (2003) reported nano zeolite A synthesis from a clear solution with a size of lower than 200 nm at a temperature of 80 0C in range of 2.05-7.89 initial Si/Al ratios. Ludox LS was used as silica source, aluminum isopropoxide as aluminum sources and TMAOH (tetramethylammonium hydroxide) as organic template. The molar composition of the synthesis solution is (5+x)SiO2 : Al2O3 : 0.17Na2O:(7-y)(TMA)2O:389H2O: 3.0iPr2O (1.1≤x≤10.8, 0.5≤y≤6.1). Figure 10 describes the procedure of nanozeolites A synthesis which was reported by Rakoczy (Rakoczy & Traa, 2003).

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Figure 10. Scheme of zeolite A synthesis (Resumed from Rakoczy & Traa, 2003) The 10-30 nm particle size of zeolite nanocrystals were obtained at room synthesis temperature for 3 day crystallization time (Mintova et al. 1999). In situ method of characterization observed the particle at 5 minutes after mixing to 10 days. The aluminosilicate solution contained small particle of up to 5 nm quickly agglomerated after addition of the organic template to form 40-80 nm amorphous aggregates. Zeolite A was nucleated in these aggregates within 3 days at room temperature. The effect of sodium content in the synthesis solution of zeolite A nanocrystal was reported by Schoeman et al. (1994). The chemicals used in the research are Ludox SM (silica source), aluminum sulfate hydrate ((Al2(SO4)3.18H2O as alumina source) and TMAOH as organic template. In the research the average particle size of 150 nm can be obtained at 1000C. The molar composition of the synthesis mixture is (1.62x)(TMA)2O:xNa2O:Al2O3:3.62SiO2:246H2O. The relative high of Na2O/Al2O3 ratio tends to form the larger particle of zeolite A nanocrystal with 0.077 of Na2O/Al2O3 ratio as the start point of crystallization. Zhu et al. (1998) focused on developing in a well controlled way high quality LTA single nanocrystal using pure reactant sources such as tetraethyl orthosilicate (TEOS), Al powder, NaCl and TMAOH. In that research, the SiO2/Al2O3 ratios were used in the range of 1.12-3.4 at 1000C for 11-18 day crystallization time. The zeolite nanocrystal products were obtained with the particle sizes of 50-500 nm. The ratios of (TMA)2O/Al2O3, SiO2/Al2O3 and NaCl/Al2O3 have essential influence on the final LTA crystal sizes. Increasing (TMA) 2O/Al2O3 ratio results in the reduction of the crystal size. It was also reported that the increase of NaCl/Al 2O3 ratio resulted in the decrease of the crystal size and longer crystallization time.

2.1.5 Synthesis of zeolite Y (FAU) nanocrystal Similar to zeolite A, colloidal zeolite Y suspension was also prepared from a clear solution at temperature up to 1300C containing tetramethylammonium cation as organic template. However the synthesis yields are often very low, just about 10%. It was reported that the sodium should be added into the crystallization solution after completion of the nucleation stage. Otherwise the system would be favored to form zeolite A crystals (Tosheva and Valtchev, 2005). The 80 nm particle size of zeolite Y was obtained by Zhu et al (1998) with synthesis molar composition of 3.4SiO 2: 0.83Al2O3: 2.3(TMA)2O:0.1NaCl: 300H2O for 14 days crystallization at 1000C. It was also found that decreasing the amount of NaCl resulted in low yield and low crystallinity of zeoliteY nanocrystal. The effect of sodium content in the synthesis mixtures was also studied by Shcoeman et al (1994). It was reported that the lower Na2O/Al2O3 ratio the higher possibility to obtain zeolite Y yield. The 75% of zeolite Y and 25% of zeolite A product were obtained from the molar composition of (1.62-x)(TMA)2O:xNa2O:Al2O3:3.62SiO2: 246H2O at 0.077 of Na2O/Al2O3 ratio. At the same molar composition, 100% of zeolite Y yield was obtained at 0.044 of Na 2O/Al2O3 ratio. In situ characterization using DLS (Dynamic Light Scattering) and XRD of zeolite Y nanocrystal was reported by Mintova (2003). According to the study, zeolite Y nano crystal was synthesized at 900C with tetramethylammonium hydroxide pentahydrate (TMAOH.5H2O) as organic template, aluminum isopropoxide and colloidal silica (SiO 2 30

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wt. %) as aluminum and silica sources, respectively. The molar composition of the synthesis mixture was 5.5(TMA)2O : 2.3Al2O3 : 10SiO2 : H2O. The precursor solution of nanozeolite Y was aging into orbital shaker for 24 hours prior to crystallization stage. The average particle size at 60 nm was obtained. Further, Holmberg et al (2003) reported nano zeolite Y synthesis (Si/Al ratio of initial solution of 4.3) with a particle size of 32-120 nm at a temperature of 100 0C. Tetramethylammonium bromide (TMABr) as a second source of organic template was used in this research to obtain smaller particle sizes. It can be proved that TMABr reduced the crystal sizes up to 32 nm of nanozeolites Y while simultaneously increasing the yield. The effect of (TMA) 2O/Al2O3 and TMABr/TMAOH ratios were also investigated. The increase in (TMA) 2O/Al2O3 results in the decrease of crystal sizes similar to the case of increasing TMABr/TMAOH ratio which also reduced particle sizes. Figure 11 describes the procedure of nanozeolite Y synthesis by Holberg et al.

Figure 11. Scheme of preparation for zeolite Y nanocrystal synthesis (Holmberg et al, 2003) 2.1.6 Synthesis of zeolite silicate-1 (MFI) nanocrystal Silicate-1 nanocrystal zeolite has received much attention from the researchers for the preparation of colloidal zeolite suspensions due to the ease of the reaction system in the synthesis process such as the absence of aluminum content and the properties such as hydrophobicity and high thermal stability. The silicate-1 precursor solution is obtained by hydrolysis of tetraethylorthosilicate (TEOS) into a solution containing tetrapropylammonium hydroxide (TPAOH) under ambient condition consisting of discrete particles with a size of about 3 nm (Tosheva and Valtchev, 2005) Persson et al (1994) reported the silicate-1 nanocrystal synthesis from a clear solution at temperature of 80-1000C with molar composition of 9TPAOH:0.1Na2O: 25SiO2:480H2O:100EtOH. The nanosilicate-1 zeolite product was in average particle size of 95 nm. It is also reported that the particle size of nanosilicate-1 crystal decreases if increasing TPAOH concentration, indicating that TPAOH influences nucleation stage in the crystallization process. Similar to Persson et al work, silicate-1 nanocrystal synthesis with a molar composition of 9TPAOH:25SiO 2: 480H2O:100EtOH was also reported by Shcoeman (1997). A very small particle size of silicate-1 at 2.8 nm was obtained at room temperature. Low synthesis temperature was also reported by Corcery and Ninham (1997). The average particle size of 55 nm of silicate-1 nanocrystal was obtained at very long synthesis time i.e. 40 months. The molar composition is 100SiO2: 15.5TPAOH: 1380-1550H2O.

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It has been found that silica sources in the nanocrystalline silicate-1 influence the particle size. Mintova and Valtchev (2002) used in situ DLS characterization to investigate the effect of TEOS, Ludox LS and Cab-O-Sil as silica sources. The precursor mixture was aging for 30 hours at room temperature and transferred into a quartz cuvette for in situ DLS measurement at 900C. The average crystal size of nanosilicate-1 after complete crystallization is 15 nm, 25 nm and 50 nm for TEOS, Cab-O-Sil and Ludox LS, respectively. It was also found that the synthesis mixture containing TEOS as silica source had a shorter crystallization time (10 hours) relative to other silica sources (15 hours). A two stage synthesis has also been developed which consists of a treatment at lower temperature followed by a quick change to higher temperature in silicate-1 nanocrystal synthesis process (Li et al, 1999). According to this method, the silicate-1 zeolite nanocrystal yield can be improved while minimizing the crystal sizes. For instance, at one stage synthesis at 600C, the obtained average particle size was 57 nm with yield of 53% meanwhile 60% yield could be obtained with similar average crystal size at two stage synthesis of 60-1000C. 2.1.7 Synthesis of zeolite ZSM-5 (MFI) nanocrystal Zeolite ZSM-5 is often used as catalyst in petroleum refining and petrochemicals such as in the field of cracking, hydrocracking, isomerization, alkylation and reforming reaction. The morphologies and properties of ZSM-5 related to crystalline structure, high internal surface area, uniform pore and good thermal stability result in the high selectivity and efficiency of ZSM-5 as a catalyst. Several variables such as silica and alumina sources, the alumina content, the template/silica ratio, the characteristics of cations in the synthesis mixture, crystallization temperature etc influence the crystallization process. It is also known that the increase of SiO2/Al2O3 and OH-/SiO2 molar ratio of initial synthesis solution will decrease particle size (Grieken et al, 2000). Grieken et al (2000) synthesized nanocrystalline ZSM-5 at 1700C from a sodium free solution using tetrapropylammonium hydroxide (TPAOH) as organic template with SiO 2/Al2O3 ratio of 60 and molar composition of Al2O3: 60SiO2: 21.4TPAOH: 650H2O. According to the report, nanocrystalline ZSM-5 synthesis was started from preliminary experiment making supersaturated solution containing silica and alumina to pursue the optimum synthesis condition. At this stage, the effect of hydrolysis time, aluminum source, alkalinity, water and sodium content were investigated. The yield of crystalline ZSM-5 increased if increasing hydrolysis time. However, the crystal size was slightly decreased. Further, the use of aluminum isopropoxide as alumina source led to the decrease of average crystal size. The increase of TPAOH concentration tends to raise the alkalinity. The research confirms that the increase of TPAOH concentration leads to a decrease in the crystallization rate. A low SiO2/Al2O3 ratio in nanocrystalline ZSM-5 synthesis was reported by Song et al (2004). According to this research, ZSM-5 was synthesized from a clear solution at 1650C with Si/Al ratio of 25. Aluminum isopropoxide and tetraethyl orthosilicate (TEOS) were used as alumina and silica sources, respectively. The two starting molar compositions of the synthesis mixture were 9TPAOH: 0.16NaOH: Al: 25Si: 495H2O: 100EtOH and 9TPAOH: 0.16NaOH: Al: 25Si: 300H2O. The hydrolysis of TEOS into ethanol has been done for 24 hours at room temperature. Ethanol then was removed by heating the synthesis solution at 80 0C to obtain the larger particle size. For the smaller particle size synthesis, the ethanol was not removed. Based on the research, the average particle size of 15 nm and 60 nm were obtained for the first and the second synthesis mixture, respectively.

2.2 Adsorption In regard to gas-solid and liquid-solid interface, adsorption is defined as the increase of liquid or gas molecule concentration on the solid surface (Malherbe, 2007). Adsorption occurs when the molecules in the fluid phase are held for a number of time by a neighboring surface force (Coulson et al, 1991). In the adsorption process, molecules spread themselves between 2 phases. The first is solid and the other is liquid or gas. Adsorption is very effective to remove trace elements from liquid phase and can be used either to recover component or to remove contaminant substance from industrial waste matter. 2.2.1 Physical and chemical adsorption There are two importance types of adsorption. One is physical adsorption and the other one is chemical adsorption. Physical adsorption is resulted from van der waals forces. This adsorption is easily to reverse because the van der waals force is not strong (Coulson et al, 1991). Electron sharing or transfer does not occur in the physical adsorption. The individuality of component interaction is always maintained. The interactions are reversible resulted from intermolecular forces of attraction between molecules of the solid and the substance adsorbed. For example, if the intermolecular attractive forces between a solute a and solid are higher than those existing between molecules of the solute itself, the solute will be collected on the solid surface (Noll & Hou, 1992)

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Chemical adsorption resulted from chemical interaction between the solid phase and the adsorbate materials. Chemical adsorption engages the electron exchange or electron sharing in a chemical reaction resulting in a change of adsorbate chemical form or possibly molecules breaking up into atoms or radicals. Therefore, it usually occurs at high temperatures and is related with activation energy. The formed chemical bond is stronger than the physical van der waals forces. The strength of the chemical bond may vary considerably, and identifiable chemical compounds in the usual sense may not actually form, but the adhesive force is generally much greater than that found in physical adsorption. Further, the adsorbed molecules are confined on the specific sites therefore they do not easily migrate among the surface. Chemical adsorption will be hardly reversed therefore the regeneration of chemical adsorption may be a problem (Noll & Hou, 1992). 2.2.2 Steps of adsorption process The adsorbent particles will attain the saturation state if all active sites have been covered with the adsorbate molecules. The active sites include the surface area through the adsorbent particles. As can be seen from Fig.12, this condition can be clarified by the following steps.

Figure 12. Schematic Representation of Adsorption by a Porous Solid (Noll & Hou, 1992). First step is external diffusion where the mass from the mass fluid phase is transferred into the external surface of the solid through an inert edge layer by diffusion of the adsorbate. Second, internal diffusion where occurs transferring of adsorbate to interior of the particle caused by the moving of the adsorbed molecule from the relative small external of the adsorbent to the surface of pores within each particle or by the diffusion of the adsorbate molecules through the pores of the particles. The rate of adsorption in porous adsorbents is generally controlled by transport within the pore network. And the third is the actual adsorption processing, this step is relatively fast occurred with adsorption of molecule in the pores from the solution to the solid. The molecules in the pores are adsorbed from the solution to the solid phase, therefore the local equilibrium is usually assumed between these two phases. These adsorption process are described schematically in Figure 12 (Noll & Hou, 1992). Adsorption mass transport steps can be seen at Figure 13. The first step, bulk transport of solute in the solution phase, it is usually very fast because of mixing and convective flow. The second step, film transport, involves diffusion of the solute through a hypothetical or hydrodynamic boundary layer. Except for a small quantity of adsorption that occurs on the outer surface of the adsorbent, the adsorbent solute then ought to diffuse within the pore volume of the adsorbent and/or along pore-wall surfaces to an active adsorption site. The real adsorption of solute on internal surface sites is normally considered to be fast, similar to an equilibrium reaction (Slejko, 1985).

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Figure 13. Mass transport steps in adsorption by porous adsorbents (Slejko, 1985) 2.2.3 Factors influencing adsorption There are three key factors usually affecting the adsorption process as can be given in detail below (Slejko, 1985). 1. Adsorbate characteristics The chemical characteristics of the adsorbate such as the size and the configuration of the certain molecules to be adsorbed are important for adsorption. There are two factors influencing adsorption process regarding size of molecular. First, for any homologous series of organic molecule solubility commonly decreases with the increase of particle size. A substance which has low solubility in water will have a higher affinity for solid surface than for the water and will have affinity to concentrate on the solid surface. Second, molecular size is also essential for the perspective that all adsorbents depend on internal surface area for the full use of their adsorption capabilities. If molecular size is too large, adsorption will be delayed and adsorption capacity will decrease as very large molecules block or cannot infiltrate pores or cavities within the adsorbent. One further aspect of molecular size is that larger molecules will have a tendency to diffuse more slowly from solution and therefore will require longer time for full equilibrium adsorption capacity. 2. Adsorbent characteristics The chemical and physical characteristics of the adsorbents which are used to remove a material from solution are also very important. Chemical properties include the degree of ionization of the surface of the adsorbent. The physical properties have most effect on the selection of the mode of application of the adsorption process using that particular adsorbent. The degree of properties can be varied by the interaction with the solution. The adsorbent can be in the form of small pieces of particles which may have a density close or very different from the solution or the adsorbent may be in very fine powdered form which may be simply suspended in the solution. 3. Solution characteristics The three most important waste solution characteristics which have particular influence on adsorption are: the solution pH, temperature, and presence of other competing adsorbate compounds. The pH of a solution is importance for its effect on the adsorbent. Both adsorbate and adsorbent may have chemical characteristic which are affected by the concentration of hydrogen ion in the solution. Some adsorbent have affinity for H + or OH-- ions and can directly affect the solution pH and also solubility and adsorption capacity. The temperature of a solution has two main consequences on the adsorption. First, the rate of adsorption is typically increased at higher temperature. This is due mainly to the increase rate of diffusion of adsorbate molecule through the solution to the adsorbent. Second, because solubility and adsorption are closely related, as temperature affects solubility it will therefore affect the extent of adsorption or capacity of the adsorbent for the particular adsorbate. The presence of materials with a particularly high affinity for the adsorbent will tend to move from the adsorbent material or lesser affinity. This effect can result in a chromatographic effect.

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2.3 Equilibrium of adsorption The adsorption equilibrium is the equilibrium relationship between the concentration in the fluid phase and the concentration in the adsorbent particles when no further net adsorption take places (Noll & Hou, 1992). For liquids, the concentration is often stated in mass units, such as part per million (ppm). The concentration of the adsorbate on the solid is given as mass adsorbed per unit mass of original adsorbent. Some characteristic equilibrium profiles can be seen from Figure 14. Normally Qe is the amount of adsorbed associated with a unit weight of solid adsorbent and Ce the residual concentration of adsorbate in the fluid phase.

Figure 14. Type of Equilibrium Sorption Separation (Slejko, 1985) The linear equilibrium goes through the origin, and the amount adsorbed is relative to the concentration in the fluid. Equilibrium is also called favorable adsorption in curve I, because a relatively high solid loading can be obtained at low concentration loading. The limiting case of a very favorable isotherm is irreversible adsorption, where the amount adsorbed is independent of concentration down to very low value. Isotherm line is also called unfavorable in curve III because comparatively low solid loading are obtained and because its quite long mass-transfer zones in the continuous mode operation system (Slejko, 1985). All systems illustrate decrease in the quantity adsorbed with an increase in temperature. Adsorbate can be removed by increasing the temperature even for the cases labeled “irreversible”. However, adsorption needs much higher temperature when the adsorption is strongly favorable or irreversible when the isotherms are linear. If the adsorption isotherm is favorable, mass transfer from the solid back to the liquid phase has characteristics similar to those for adsorption with an unfavorable isotherm. Isotherm studies are valuable for adsorption capacity, selection of adsorbent and determination of adsorbent quantity. Furthermore, the isothermal equilibrium is useful in evaluation of a design of adsorption system and calculation modeling procedures. The quantity of adsorbed solid can be supposed that no solvent adsorption and a minor change occurs in the total moles of the liquid mixture (constant T and P). Adsorption capacity of the adsorbent at equilibrium (Qe, mg/g) can be calculated by using the following equation (Eq. 1 or 2).

Qe 

(C0  Ce )V W

(1)

Qe 

(C0V0  CeVe ) W

(2)

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Where Co and Ce are the initial and final concentrations, V 0 and Ve are the initial and final volumes (if the volumes of adsorption system are changed), and W is the weight of adsorbent (Wang & Zhu, 2006). 2.3.1 Langmuir Isotherm Model The Langmuir isotherm was originally developed to represent chemisorption on a set of distinct localized adsorption sites. The Langmuir isotherm has an assumption that the adsorption occurs within adsorbent at specific homogeneous sites (Wang et al, 2006). Eq. (3) shows the common form Langmuir isotherm equation.

Qe 

K L .Qmax .Ce 1  K L .C e

(3)

Where Qe is adsorption capacity at equilibrium (mg/g), Q max is the maximum adsorption capacity (mg/g), Ce (mg/l) is the solution concentration at equilibrium, and KL is the Langmuir constant (l/mg) which related to the adsorption energy. The following equation (Eq. 4) is the linear form of the Langmuir equation (Zhang & Bai, 2003).

Ce 1 1   Ce Qe KLQ max Q max

(4)

2.3.2 Freundlich Isotherm Model There are two assumptions of Freundlich relationship model. Firstly, no further association or dissociations of the molecules after the molecules adsorbed on the adsorbent surface. Secondly, there is a complete absence of chemisorption or Freundlich isotherm will be valid if the adsorption process is purely a physical process with no change in the configuration of the molecules in the adsorbed state. The general equation of Freundlich model is:

Qe  K F .Ce

1/ n

(5)

Where Qe is adsorption capacity at equilibrium (mg/g), Ce is the concentration at equilibrium (mg/l), KF and n are the Freundlich constants. The value of KF can be taken as a relative indicator of adsorption capacity while 1/n is indicative of the energy or intensity of reaction. The values of Q max, KL (Eq.2), KF and n (Eq.3) are calculated from the intercepts and slopes of the equations plots. The linear form equation of the Freundlich isotherm is listed as follows (Frimmel & Huber, 1996):

1 log Qe  log KF  log Ce n

(6)

2.4 Kinetics of Adsorption The dynamic adsorption data were processed to understand the kinetics of adsorption process in terms of the order and rate constant. The Lagergren kinetics of the first order and second order equation has been most widely used for the adsorption of an adsorbate from an aqueous solution. 2.4.1 Pseudo first order kinetics The adsorption data were firstly treated with the pseudo first order kinetic model. The differential equation is the following (Juang et al, 2000 and Chang & Juang, 2005).

Qt  Qe (1  e  k1t )

(7)

Where Qe and Qt refer to the amount of adsorbate adsorbed (mg/g) at equilibrium and at any time, t is times (hours) respectively, and k1 is the equilibrium rate constant of the pseudo first order sorption (hour-1). Integrating Eq. (7) at the boundary conditions t = 0 to t and Qt = 0 to Qt gives:

log

Qe k  1 t Qe  Qt 2.303

(8)

The pseudo first order reaction. Eq. (8) can be rearranged to obtain a linear form at Eq. (9) or Eq. (10)

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log( Qe  Qt )  log Qe 

k1 t 2.303

ln(Qe  Qt )  ln Qe  k1t

(9)

(10)

Values of the rate constant k1, equilibrium adsorption capacity, Qe, and the correlation coefficient, R 2, were calculated from the plots of ln(Qe-Qt) versus t. Further, the Qe will be obtained from the plot should also be close to the Qe obtained from experiment if the kinetics follows the pseudo first order model. Equation (9) or (10) can be transformed into a nonlinear form, which can be used to better predict the adsorption equilibrium if the equilibrium adsorption is not known:

Qt  Qe (1  e  k1t )

(11)

2.4.2 Pseudo second order kinetics On the other hand, a pseudo-second-order equation based on adsorption capacity can be expressed in the following form (Zhang & Bai, 2003 and Frimmel & Huber, 1996).

dQt  k 2 (Qe  Qt ) 2 dt

(12)

Where Qe and Qt are amount of adsorbate per mass unit of adsorbent (mg/g) at equilibrium and specific times, k 2 (g/mg.h) are the rate constants of the first and second order kinetics. Integrating Eq. (10) for the boundary conditions t = 0 to t and Qt = 0 to Qt gives:

1 1   k 2 .t Qe  Qt Qe

(13)

The Eq. (13) can be rearranged to obtain a linear form:

t 1 1   t 2 Qt k 2 Qe Qe

(14)

If the pseudo second order kinetics is applicable, the plot of t/Qt versus t should show a linear relationship. The second order rate constant, k2, and the equilibrium adsorption capacity, Qe were calculated from the intercept and slope of the plots of t/Qt versus t. 2.5 Multi-component Adsorption Equilibrium Phenomenon In order to successfully signify the dynamic adsorptive behavior of any substance from fluid to solid phase, it is importance to have appropriate description of the equilibrium condition between the two phases creating the adsorption system. Competitive activities and displacement effect are typical phenomenon in multi-component adsorption system. Because of the adsorption sites on the surface of the sorbent are limited, the adsorption of any adsorbate in a mixture is controlling species. A sorbate having strong affinity with the sorbent and weak affinity with the solvent usually represents a strongly adsorbed species therefore the sorbate has a high adsorption capacity. In a mixture, the strongly adsorbed species always has a greater tendency to live in the adsorption sites than weakly adsorbed species. Therefore, the adsorption of the weakly adsorbed species decreases more than the strongly adsorbed species. 2.6 Zeolites as adsorbent Most adsorbents are highly porous materials, and adsorption takes place principally on the wall of the pores or at specific sites inside the particle. Because the pores are usually very small, the internal surfaces are in orders of magnitude greater than the external area. Separation occurs because differences in molecular weight or polarity cause some molecules to be held more strongly on the surface than others. In many cases, the adsorbing component (or

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adsorbate) is from the liquid with very little adsorption of other components. Regeneration of the adsorbent can then be carried out to obtain the adsorbate in concentrate or nearly pure form. One of these adsorbents is zeolite. Zeolite is aluminosilicates with 3D framework complex, inorganic crystalline base on an infinitely extending framework of Al2O3 and SiO2 tetrahedral linked to each other by the 22 sharing of oxygen ions. Molecular sizes of 6, 8, 10 and 12 member ring opening are ranged between 3 to 7.5 Å (Botto et al., 2004). This framework structure contains channels or interconnected voids that are filled by water or other guest molecules. The cations are mobile and ordinarily undergo ion exchange. The water may be removed reversible, normally by the submission of heat, which leaves intact a crystalline host structure permeated by microporous which may mount to 50 % of the crystals by volume. If the system is three-dimensional, a cation or molecule of appropriate size can diffuse into any accessible site in the crystal. If the system is two-dimensional, the molecule can only move in the plane. In the one-dimensional system, movement is possible only in one direction. Zeolite can be supposed to contain three types of pores: firstly, macropores are defined as those pores in which diffusion rates are unhindered by the pore walls, and rapid initial uptake of adsorbate is assumed to occur (pores opening >500Å). Secondly, micropores are those pores with radius of comparable size to the diffusing species (pores opening <20Å). The micropores are assumed to branch off the macropore network, and are assumed to be homogeneously distributed throughout the particle. And thirdly is mesopores which have pore opening of 20-500 Å. Zeolites are high capacitive and selective adsorbents because they separate molecules based on the size and configuration of the molecules relative to the size and geometry of the main opening of the structure which show other interaction effects, with selectiveness that it is not found in other solid adsorbents. Zeolite selectively adsorbs or rejects molecules based on differences in molecule size, shape, and other properties such as polarity. The main part of the adsorption capacity is contained in the voids within the crystals. When two or more molecular species involved in as separation are both adsorbed, selectivity becomes important because of interaction between the zeolite and the adsorbate molecule. In zeolite adsorption processes, the adsorbates migrate into the zeolite crystals. First, transport must occur between crystals contained in a compact or pellet, and second, diffusion must occur with crystals. Factors affecting kinetics and diffusion include: channel geometry and dimensions, molecular size, shape, and polarity, zeolite cation distribution and charge, temperature, adsorbate concentration, impurity molecules, and crystal-surface defects. 2.7 Interaction Forces Physical adsorption on non polar solids is attributed to forces of interaction between the solid surface and adsorbate molecule that are similar to the Van Der Waals forces (attraction-repulsion) between molecules (Noll & Hou, 1992). Nonpolarity on natural zeolite depends on its composition especially the ratio Si/Al. When zeolite is dealuminated by acid treatment, the Si/Al ratio can increase and the result that water-adsorption capacity is essentially eliminated and the zeolite becomes hydrophobic which means high tendency to have nonpolar behavior which affects its selectivity, high tendency to adsorb organic compounds and low tendency toward inorganic compounds. Interaction forces involving electrons and nuclei of the system are termed dispersion force (Noll & Hou, 1992). These forces exist in all the types of matter and always act as an attractive force between adjacent atoms and molecules. Besides surface tension and porosity are other factors involved interaction forces. Surface tension requires the surface free energy to bring the molecule from bulk of the liquid into the surface against the inward attraction force. The porous nature of the zeolite determines its adsorptive properties. 2.8 Adsorption of heavy metals As mentioned in the previous chapter that the research in heavy metal removal by using zeolite in nano size particle is less developed. The reason is probably because of the cost of nanocrystalline zeolite synthesis. However, heavy metal removal by using nanozeolites is important for developing of knowledge particularly in nanozeolite application area. This study will give a horizon for the effectiveness of nanosize zeolite as heavy metal adsorbent. 2.8.1 Types of heavy metal of interest Although most of heavy metals are highly toxic and are not biodegradable, some of them such as Pb 2+, Cu2+, Fe3+, and Cr3+ are common groundwater contaminants at industrial installation (Erdem et al, 2004). Moreover, Pb 2+, Cu2+, Fe3+, and Cr3+ tend to accumulate in organisms and causing numerous diseases and disorder (Inglezakis et al, 2007). According to Naseem & Tahir (2001), lead (Pb) can damage to kidney, liver and reproductive system, basic cellular processes and brain function. Other researchers, Basadella et al (2007) reported that Cr3+ presents in many industrial and manufacturing processes such as leather tanning, steelworks and chromium electroplating. Chromium (III) is indeed less toxic than Chromium (VI), however, Cr 3+ can be oxidized to Cr6+. Therefore, controlling the chromium

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(III) is also very important (Natale et al, 2007). Thus, heavy metal ions of Pb 2+ and Cr3+ have been chosen in this investigation. Table 4 depicts the physical properties of lead and chromium (III). Table 4. Physical properties of lead and chromium Properties

Heavy metal Lead

Phase Density (near r.t.) Liquid density at m.p.

solid 11.34  g·cm−3 10.66  g·cm−3 600.61 K Melting point (327.46 °C, 621.43 °F) 2022 K Boiling point (1749 °C, 3180 °F) Heat of fusion 4.77  kJ·mol−1 Heat of vaporization 179.5  kJ·mol−1 Heat capacity (25 °C) 26.650  J·mol−1·K−1 (http://en.wikipedia.org, retrieved: 15 September 2007)

Chromium solid 7.15 g·cm−3 6.3 g·cm−3 2180 K (1907 °C, 3465 °F) 2944 K (2671 °C, 4840 °F) 21.0 kJ·mol−1 339.5 kJ·mol−1 (25 °C) 23.35 J·mol−1·K−1

2.8.2 Lead and chromium removal Many researchers reported the heavy metal removal in water and waste water particularly for lead (Pb) and chromium (Cr). For instance, Inglezakis et al (2007) studied the Pb removal from aqueous solution by using natural zeolite of clinoptilolite as adsorbent. Based on the result, the highest removal level of Pb is 55% on natural zeolite of clinoptilolite. Another Pb removal was also reported by Ok et al (2007). The used adsorbent was a formulated zeoliteportland cement mixture (ZeoAds). Based on the experiment, the maximum adsorption capacity of the ZeoAds for Pb was 27.03 mg/g and it was higher than 18.35 mg/g of activated carbon. It was also reported that the increase of pH would increase adsorption capacities. The much higher adsorption capacity of Pb was reported by Nah et al (2006). By using synthetic zeolite (particle size of 74µm) and magnetically modified zeolite (MMZ), they obtained the adsorption capacities of Pb as 251 mg/g and 123 mg/g. Moreover, Terkiatburana et al (2007) reported Pb removal from aqueous solution by using zeolite MCM-22 and activated carbon. The adsorption capacities of Pb for both MCM-22 and activated carbon are 94 mg/g and 61 mg/g respectively (Terkiatburana, 2007) Chromium removal also received much attention. By using Bentonite clay, Tahir & Naseem (2007) reported the removal of chromium (III) from tannery waste water. According to the adsorption study by Langmuir model, the adsorption maximum capacity of chromium (III) is 49.75 mg/g. The adsorption was increased from 22 to 90% by increasing pH from 1.6 to 2.5 and then decreased to 23% at pH of 5.6. Natale et al (2007) studied the chromium adsorption on activated carbon and char. It was found that the adsorption was well performed with the maximum value of adsorption capacities at the pH in range of 5-8. The LTA zeolite was used as a chromium adsorbent by Basaldella et al (2007) particularly in the study of pH effect. It was found that removal of chromium from solution was remarkable at very short contact time. By adding relatively large amount of 3 g of LTA zeolite, the Cr3+ content can be reduced until complete removal from the solution in the first minute at pH of 6. Another zeolite i.e. FAU type material with an average particle size of 180 nm was reported. The zeolite exhibited higher selectivity and removal capacity of chromium than commercial zeolite (Covarrubias et al, 2006). Beside pH, other variables such as temperature, initial concentration, amount of adsorbent, initial Si/Al ratio and particle size also affect the adsorption performance. Wang et al (2006) reported that the increase of treatment temperature favors the increase of adsorption capacity due to the increase in surface area and pore volume. The correlation can also be found with treatment time, initial concentration of heavy metal ions and the amount of adsorbent. 2.8.3. Binary system The competition of adsorbate occurred in binary system and multi component adsorption. The competition between different heavy metal species for adsorption depends on their ionic characteristics. The preference of the zeolite for one cation rather than the other in binary system adsorption depends on the Si/Al ratio, the exchangeable cation of the starting zeolite (co-ions), the hydration ratio of the co-ion and the in-going ions as well as temperature and the three dimensional zeolite frameworks.

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Wang & Ariyanto (2007) reported competitive adsorption of Pb ions and malachite green (MG) on natural zeolite. It was found that the adsorption capacities of the adsorbate could be decreased by 10-20 % in binary system compared with single component adsorption. Terkiatburana et al (2007) reported the competition and complexation of heavy metal ion (Pb2+ and Cu2+) and humic acid on zeolitic MCM-22 and activated carbon. It was found that Pb 2+, Cu2+ and humic acid would take longer time to reach equilibrium in binary adsorption system. In comparison between lead and chromium, many studies have been done on various zeolites to determine the order of heavy metal selectivity. For instance, Erdem et al (2004) determined the heavy metal ion selectivity on clinoptilolite zeolite as Pb2+ > Cd2+ > Cs+ > Cu2+ >Co2+ > Cr3+ > Zn2+ > Ni2+ > Hg2+. Inglezakis et al (2002) also studied the ion adsorption including Pb2+ and Cr3+ on clinoptilolite and found that equilibrium was more favorable for Pb2+ than Cr3+. Moreover, Ouki and Kavannagh (1999) reported the heavy metal selectivity of chabazite zeolite as Pb2+ > Ni2+ > Cu2+ > Cd2+ >Zn2+ > Cr3+ > Co2+ in multi components system. Competitive adsorption of Pb2+, Cu2+ and Cd2+ ions on microporous titanosilicates ETS-10 in binary system Pb2+Cu2+, and Pb2+-Cd2+ also reported by Lu et al (2005). It was reported that such an adsorption behavior indicates the possible underlying adsorption mechanism: when the adsorbent contacts with the adsorbate, both heavy metal (Pb 2+ and Cu2+) ions adsorbed on the surface of adsorbent. Because Pb 2+ has stronger affinity than Cu2+ on ETS, the former competitively replaced Cu2+ ions that had previously adsorbed onto adsorbent, resulting in the dissorption of Cu 2+ ion into the solution. Eventually, Pb2+ predominately adsorbed on ETS over Cu2+. Barros et al (2003) reported heavy metal ion removal by using zeolite Y and X in the binary system of Cr-K, Cr-Mg and Cr-Ca. It was found that the dynamic selectivity of the adsorption followed the order of Cr 3+>Ca+, Cr3+>Mg2+ and Cr3+>K+ for zeolite Y and Ca2+≈Cr3+, Mg2+>Cr3+ and Cr3+>K+ for zeolite X due to the more favorable mass transfer parameter and higher affinity of the ions. Based on the research, Barros et al concluded that zeolite Y had more dynamic affinity for the trivalent cation. Further, zeolite X also preferred the chromium to the potassium cation while for the system of Cr-Mg/zeolite-X and Cr-Ca/zeolite-X, saturation of the competing cation and chromium cation started almost simultaneously (Barros et al, 2003) The competing in-going ions can alter the ion exchange mechanism as they may interact with chromium ions, and more they can be exchanged at available sites, decreasing chromium uptake. It was interesting to note that some observed C/C0 (concentration in fluid relative to that in fluid) which is higher than 1 suggests a sequential ion exchange. When the available sites were saturated, chromium ions seemed to displace to competing cation already located in the zeolite, releasing them to the fluid phase. This phenomenon had already been observed in NaY zeolite (Gazola et al, 2006). Therefore, this sequential ion exchange is also a reasonable explanation for the chromium uptake in zeolite X and Y. The sequential ion exchange probably occurred due to two main factors: the selectivity of the ion exchanger itself and the operational condition used in the packed bed. Depending on the cation-framework interaction, which takes into account the change and the hydration energy of the cation and also the CEC of the zeolite, it may prefer one cation over another (Barros et al, 2003).

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