Prosiding Bandung

PROSIDING SEMINAR NASIONAL ZEOLIT VI

Bandung. 2-4 November 2009

IKATAN ZEOLIT INDONESIADarmaga Pratama Blok B No.4, Cibadak Ciampea, Bogor

Telepon/Fax: 0251-8624334Email: sekretariat [email protected]

Editor : I. G. Ngurah Ardha, Pramusanto, Trisna Soenara, Tendi Suhendi

Suwardi, Yateman Ariyanto, Siti Amini, HusainiSeptian Tri Putranto

ISBN 978-602-96414-0-0

ISBN 978-602-96414-0-0

Prosiding Seminar Nasional Zeolit VI, i Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

ISBN 978-602-96414-0-0

Prosiding

Seminar Nasional Zeolit VI

Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam

Bidang Industri, Pertanian, dan Lingkungan

Bandung, 2-4 November 2009

Editor :

I. G. Ngurah Ardha, Pramusanto, Trisna Soenara, Tendi Suhendi Suwardi, Yateman Ariyanto, Siti Amini, Husaini

Septian Tri Putranto

IKATAN ZEOLIT INDONESIA 2009

ii Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

SUSUNAN PANITIA

Pembina/ : Dr. Yateman Ariyanto

Penanggungjawab : Dr. Siti Amini

Dr. Suwardi

Steering Commitee/ : Dr. Siti Rochani

Editor Prof. I. G. Ngurah Ardha

Prof. Pramusanto

Ir. Trisna Soenara

Ir. Tendi Suhendi

Ketua : Prof. Husaini

Wakil Ketua : Toni Toha Afandi, MBA

Sekretaris : Dessy Amalia, ST

Sekretariat : Agus Wahyudi, S.Si

Azhari, ST

Ari Ariansyah

Bachtiar

Irma

Ir. Zulkarnaen

Bendahara I : Isyatun Rodliyah, S.Si

Bendahara II : Ir. Sariman

Seksi Perlengkapan/ : Ir. Budhy Agung

Acara & Pameran Rezky Iriansyah A., ST

Hanny Fauziah, SS

Rikky Andriansyah

Deni Nurul Kamal

Tjetje Djumhana

Seksi Konsumsi : Dra. Yuhelda Dahlan

Seksi Dokumentasi : Ajay Jazuli

Prosiding Seminar Nasional Zeolit VI, iii Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

KATA PENGANTAR

Ikatan Zeolit Indonesia (IZI) adalah himpunan yang mewadahi para peneliti,

pengguna, dan pemerhati zeolit. Zeolit merupakan mineral alumino silikat terhidrat

dan berongga yang memiliki kation-kation alkali dan alkali tanah. IZI dibentuk pada

tanggal 14 September 1999 di Jakarta. Akte pendirian IZI telah mendapat legalitas

dari Notaris pada tahun 2003. Anggota IZI merupakan para peneliti di lembaga-

lembaga penelitian, perguruan tinggi, dan para pemerhati zeolit baik praktisi di

lapangan dan para pengusaha zeolit. Kegiatan utama IZI adalah melakukan tukar

pengalaman tentang hasil-hasil penelitian zeolit dan publikasi dalam bentuk jurnal

zeolit.

Dari hasil seminar nasional I (tahun 2000) dan II (tahun 2001) masing-masing telah

diterbitkan prosiding seminar nasional zeolit, sedangkan penerbitan JZI perdana

memuat artikel-artikel terpilih dari hasil seminar sehari tahun 1999. Selanjutnya,

mulai seminar nasional III yang diadakan pada bulan Mei 2003, makalah-makalah

yang telah diseleksi dapat diterbitkan pada Jurnal Zeolit Indonesia (JZI). Selain hal

tersebut, terdapat juga beberapa artikel di luar artikel yang dipresentasikan pada

seminar nasional IZI, setelah melalui penyeleksian oleh tim editor. Tradisi seminar

zeolit III dilanjutkan pada seminar IV dan V dengan menyeleksi makalah untuk

penerbitan JZI.

Penyelenggaraan Seminar Zeolit VI di Bandung 2-4 November 2009 terasa sangat

istimewa dibandingkan dengan seminar-seminar sebelumnya karena dalam seminar

tersebut kami memperoleh bantuan pendanaan pendanaan dari Departemen

Pendidikan Nasional. Dari pemberian dana tersebut kami harus bekerja lebih keras

lagi kaarena paper yang dihasilkan bukan hanya untuk diterbitkan di JZI tetapi

dipacu untuk dapat terbit di jurnal nasional terakreditasi, jurnal regional, dan bahkan

ke jurnal internasional.

Dengan gambaran perkembangan IZI dalam penyelenggaraan Seminar Nasional I-VI

terlihat adanya perkembangan yang sangat baik dari hanya menghasilkan makalah

dalam prosiding, diterbitkan dalam Jurnal Zeolit Indonesia, dan kemudian

diharapkan dapat terbit pada jurnal internasional. Dengan dorongan Departemen

iv Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Pendidikan Nasional mudah-mudahan tradisi seminar yang menghasilkan paper yang

terbit pada jurnal internasional akan menjadi tradisi yang dapat dipertahankan. Kami

akan terus berusaha agar pada tahun-tahun mendatang penyelenggaraan seminar

nasional akan menghasilkan paper-paper yang makin berkualitas dan dapat terbit

pada jurnal yang berkualitas dan lebih bervariasi.

Editor April 2010

Prosiding Seminar Nasional Zeolit VI, v Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

DAFTAR ISI

KATA PENGANTAR ................................................................................................................ iii DAFTAR ISI................................................................................................................................ v

Hydrothermal Synthesis Of Mesoporous Mcm-41 Materials From Fly Ash: The Influence Of Naoh/Fly Ash Weight Ratio And Ph Of Precursor Solution (Sutarno, Yateman Arryanto, And Susanna Ardhani Nugroho).............................................................. 1 Anion Exchange Capacity Of Chromate On Modified Zeolite Clinoptilolite With Hdtma-Br and Its Regeneration (Widajanti Wibowo, Tresye Utari, Rika Tri Yunarti) ....................................................................................................................................... 15 Characterization And Measurement Of Pore Size Of The Framework Structure Of Natural Zeolite (Supandi Suminta And Mardiyanto) ............................................................. 24 Production Process Of H-Zeolit Catalyst From Zeolite Rocks Indonesia For Ethanol Dehydration Process: The Effect Of Solvent Type And Temperature (Widayat, A Roesyadi And M Rachimoellah) ......................................................................... 37 The Influence Of Si/Al/P Ratios On The Structure Of Microporous Silico Alumino Phosphate (Amini, S, Arif Nugroho) ......................................................................................... 48 Influence Of Process Condition Of Natural Zeolite Activation Process To Cation Exchange Capacity (Cec) Value Of Treated Zeolite With Cikalong-Tasikmalaya Natural Zeolit As A Case (Endang Sri Rahayu, Rivai Tongon, Paramitha Sarianta) ..................................................................................................................................... 58 Potensi Zeolit Di Indonesia (Kusdarto) ...................................................................................... 64 Kapasitas Penukaran Ion Cs Dari Zeolit Bayah, Lampung Dan Tasikmalaya (Noviarty,Dian Anggraini, Arif Nugroho) ............................................................................... 78 Teknik Aplikasi Zeolit di Bidang Pertanian Sebagai Bahan Pembenah Tanah (Suwardi) .................................................................................................................................... 85 Degree Of Uniformity Of Solid-Solid Mixing Urea And Natural Zeolite For Slow Release Fertilizer Production Using Orbiting Screw Mixer (Semuel Pati Senda, Renanto Handogo, Achmad Roesyadi, Wahono Sumaryono) ............................................... 94 The Utilizing Of Zeolite Mineral As Agricultural Soil Conditioner In Relation To Its Standardization And Increasing Food Crop (M. Al-Jabri ) ................................................. 103 Mengatasi Degradasi Lahan Melalu Aplikasi Pembenah Tanah (Kajian Persepsi Petani Di Kabupaten Malang, Provinsi Jawa Timur) (S. H. Talaohu) .................................... 121 Aplikasi Zeolit Pada Tanah Berpasir Untuk Media Pembibitan Kelapa Sawit (S Rahutomo, Winarna, H Santoso, dan E. S. Sutarta) ............................................................ 140 Pertumbuhan Vegetatif Tanaman Anggrek Dendrobium (Dendrobium Sp.) Pada Aplikasi Zeolit Sebagai Campuran Media Tanam Dan Pupuk Pelengkap Cair (Azlina Heryati Bakrie) ........................................................................................................... 148

vi Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Pupuk Lepas Lambat Npk Di Perkebunan Teh Dengan Zeolit Sebagai Salah Satu Filler (Pudjo Rahardjo) ............................................................................................................ 159 Pemanfaatan Zeolit Sebagai Bahan Pembuatan Biopestisida Berbahan Aktif Nematoda Steinernema Spp. Berbentuk Granuler (Dr. Ir. Bambang Setyobudi, MS, Ir. Wagiyana, MS) ............................................................................................................ 171 Performa Mencit Jantan (Mus Musculus) Umur 28-63 Hari Pada Alas Kandang Sekam, Pasir Dan Zeolit Dengan Dan Tanpa Sekat Alas. (Rakhmadi, I., Muladno, H.C.H. Siregar Dan P.H. Siagian) .......................................................................................... 179 Pola Pelepasan Nitrogen dari Pupuk Tersedia Lambat (Slow Release Fertilizer) Urea-Zeolit-Asam Humat (Ganda Darmono Nainggolan, Suwardi, dan Darmawan) ............................................................................................................................... 199 Efek Takaran Zeolit Terhadap Pertumbuhan Kadar Kadmium Pupus Dan Hasil Tanaman Selada (Lactuca Sativa L.) Pada Cekaman Logam Berat Kadmium (Noertjahyani dan Nunung Sondari)...................................................................................... 212 Pengaruh Pupuk Slow Release Urea- Zeolit- Asam Humat (Uza) Terhadap Produktivitas Tanaman Padi Var. Ciherang (Kurniawan Riau Pratomo, Suwardi, Dan Darmawan) ....................................................................................................................... 222 Ekstraksi Alumina Dari Residu Bauksit Untuk Bahan Baku Zeolit Sintetis Dengan Produk Samping Konsentrat Besi (Muchtar Aziz) ................................................................... 230 The Preparation Of Tio2 Photocatalysts On A Natural Zeolite And Their Photocatalytic Reactivity For The Degradation Of 2-Propanol (Diana Rakhmawaty, Santhy Wyantuti, Masato Takeuchi, Masakazu Anpo) ............................... 240 Synthesis And Characterization Of Mesoporous Ts-1: Effect Of The Hydrothermal Crystallization Time To The Solid Structure (Alfa Akustia Widati, Didik Prasetyoko) ............................................................................................................................... 255 Catalytic Performances Of Fe2o3/Ts-1 Catalyst In Phenol Hydroxylation Reaction (Cholifah Endahroyani, Didik Prasetyoko) ........................................................................... 263 Extraction Of Alumina From Bauxite Residue For Preparation Of Synthetic Zeolite With Iron Concentrate As By Product (Muchtar Aziz And Agus Wahyudi) ........................ 276 Synthesis Of Nanoporous Zeolite (Zsm-5) From Coal Fly Ash (Bambang Sunendar Purwasasmita, Agung Kurnia, Arie Wibowo) ..................................................... 287 Pengaruh Waktu Dan Perbandingan Si/Al Terhadap Pembentukan Zeolit A Dari Abu Dasar Bebas Karbon Dari Pltu Pt. Ipmomi Dengan Metode Hidrotermal (R.A Syukuri Nikmah, Nurul Widiastuti, Hamzah Fansuri) ........................................................ 295 Adsorpsi Cu(Ii) Pada Zeolit A Yang Disintesis Dari Abu Dasar Batubara Pt Ipmomi Paiton (Nurul Faradilah Said, Nurul Widiastuti) .................................................... 311 Sintesis Dan Karakterisasi Zsm-5 Mesoporous Dengan Variasi Rasio Sio2/Al2o3 (Susi Nurul Khalifah, Didik Prasetyoko) ............................................................................... 326 Sintesa Dan Karakterisasi Komposit Zeolit-Resin Polimetakrilat ( Yusuf Nampira) .............. 336

Prosiding Seminar Nasional Zeolit VI, vii Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Hidrolisis Lempung Dari Kecamatan Capkala Dengan Variasi Konsentrasi Asam Klorida (Nelly Wahyuni, Imelda HS, Yateman Arryanto, Sutarno, Ya Zupriadi) ................................................................................................................................... 345 Desulfurisasi Minyak Solar Dengan Menggunakan Adsorben Zeolit Alam (Anda Lusia dan Baity Hotimah) ....................................................................................................... 360 Pembuatan Fotokatalis Tio2-Zeolit Alam Asal Tasikmalaya Untuk Fotodegradasi Methylene Blue (Arfan Sani A, Atiek Rostika N, Diana Rakhmawaty) .............................. 367 Kinetika Siklisasi Asetilasi (R)-(+)-Sitronelal Dengan Anhidrida Asam Asetat Terkatalis Zn2+ Zeolit Alam (Edy Cahyono, M.Muchalal, Triyono, Harno Dwi Pranowo) ................................................................................................................................... 380 Pembuatan Zeolit Y Dan Usy Untuk Komponen Aktif Katalis Perengkahan (Subagjo ) .................................................................................................................................. 390 Peningkatan Kualitas Refraktori Alumina Silikat Untuk Peleburan Kuningan Dengan Teknik Infiltrasi (Ferli S.Irwansyah , Juliandri, Iwan Hastiawan, Soewanto Rahardjo, Rifki Septawendar) .............................................................................. 399 Hidroksilasi Fenol Dengan Menggunakan Katalis Moo3/Ts-1 Yang Dikalsinasi Pada Suhu Bervariasi (Anis Farika, Syafsir Akhlus, Didik Prasetyoko)............................... 412 Pengaruh Konsentrasi NaOH dan Temperaturpadasintesis Zeolit Dari Abu Layang Secara Alkali Hidrotermal (Jumaeri,Sutarno, Eko Sri Kunartidan Sri Juari Santosa) ..................................................................................................................................... 424 Karakterisasi Keramik Tahan Peluru Pelindung Bodi Panser (Juliandri, Kautzar Buchori, Soewanto Raharjo) ................................................................................................... 442 Pengaruh Konsentrasi Cu Dalam Cu-Zeolit Terhadap Daya Antibakteri Pada Streptococcus Mutans (Dyah Irnawati, Purwanto Agustiono, Endi Hanifah Wardhani) ................................................................................................................................. 452 Penghilangan Logam Berat Dalam Larutan Dengan Zeolit Alam (Saryati, Supardi, Supandi S, Rohmad S) ............................................................................................. 463 Surfactant Modified Kaolin As A Carrier Material For Gibberellic Acid (Sunardi, Yateman Arryanto, Sutarno) .................................................................................................. 472 Modifikasi Zeolit Alam Sebagai Material Molekular Sieve Pada Proses Dehidrasi Bioetanol (Khaidir, Dwi Setyaningsih dan Hery Haerudin) ................................................. 487 Rekayasa Mineral Zeolit Dengan Teknik Wet Impregnation Logam Inhibitor Sebagai Bahan Dasar Anti-Septik Dengan Metode Aliran Kontinyu (Lenny Marilyn Estiaty) ....................................................................................................................... 506 Modifikasi Zeolit Alam Melalui Penanaman Inhibitor Cu Dengan Metode Batch Sebagai Bahan Baku Obat Anti-Septik (Dewi Fatimah) ........................................................ 521 Kinetika Dan Difusi Penukaran Ion Cs Ke Dalam Zeolit Bayah, Lampung Dan Tasikmalaya (Dian Anggraini, Noviarty, Arif Nugroho) ....................................................... 541

viii Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Analisis Isotop Cs Dalam Proses Pemisahan Cs Dengan Zeolit Menggunakan Spektrometri- (Arif Nugroho, Dian Anggraini, Noviarty) ................................................... 547 Pengaruh Konsistensi Dan Larutan Pengaktif Pada Proses Aktivasi Zeolit Alam Secara Hydrothermal Untuk Pengolahan Air Sadah Dalam Kolom Unggun Tetap (Endang Sr, Adu Damilsun, Krisna Aditia) .......................................................................... 553 Pengolahan Limbah Uranium Menggunakan Alumino Siliko Fosfat (Aisyah, Herlan Martono, Wati) ............................................................................................................ 561

Hydrothermal Synthesis of Mesoporous Mcm-41 Materials from Fly Ash: The Influence of NaOH/Fly Ash Weight Ratio and pH of Precursor Solution

Prosiding Seminar Nasional Zeolit VI, 1 Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

HYDROTHERMAL SYNTHESIS OF MESOPOROUS MCM-41 MATERIALS FROM FLY ASH: The Influence of NaOH/Fly Ash

Weight Ratio and pH of Precursor Solution

Sutarno, Yateman Arryanto, and Susanna Ardhani Nugroho

Chemistry Department, Faculty of Mathematics and Natural Sciences,

Universitas Gadjah Mada, Sekip Utara PO BOX BLS-21 Yogyakarta-55281 Email: [email protected]

ABSTRACT

Hydrothermal synthesis of mesoporous MCM-41 materials from fly ash has been successfully conducted via two main treatments, i.e.: fusion of fly ash with NaOH at 550 oC for 1 hour and hydrothermal reaction at 100 oC for 72 hours using tetramethylammonium hydroxide (TMAOH) and cetyltrimethylammonium hydroxide (CTAOH) surfactants as structure directing agent. By calcination, the surfactant was effectively removed from as-synthesized MCM-41 without structural damage. The optimum conditions were studied by several variables such as NaOH/fly ash weight ratio, pH of precursor solution, Si/Al mol ratio, and surfactant/Si mol ratio. The influence of Si/Al mol ratio and surfactant/Si mol ratio in the precursor solution in the synthesis of MCM-41 from fly ash has been previously reported (Sutarno et al., 2003; Sutarno et al., 2004). Results of this study showed that the lower NaOH/fly ash weight ratio as well as the lower pH resulted the higher order of crystallinity of MCM-41. Although hydrothermal reaction was conducted under the condition of relatively high Na concentration, however, MCM-41 could be formed as far as the reaction was conducted under controlled pH conditions.

Keywords: fly ash, fusion, hydrothermal, pH, MCM-41.

INTRODUCTION

The synthesis of mesoporous molecular sieves from fly ashes is an undoubtedly new and

interesting direction of use of the values of fly ash, and specifically its chemical

composition (Si, Al), for obtaining high-quality porous materials offering wide

possibilities of utilization (Hui and Chao, 2006; Misran et al., 2007; Chandrasekhar and

Ahn, 2008; Majchrzak-Kucba et al., 2009). Fly ash was converted into mesoporous

aluminosilicate in the hexagonal phase (MCM-41) by hydrothermal reaction using

cationic cetyltrimethylammonium bromide (CTAB) surfactants (Chang et al., 1999). The

MCM-41 from fly ash showed a homogeneous chemical composition with Si/Al=13.4

even though it contained significant amounts of impurities such as Fe, Ca, K, S, and P.

The fact that MCM-41 could be synthesized from fly ash indicated that the impurities in

the fly ash sample are not detrimental to the formation of MCM-41.

Mesoscopic inorganics can be processed by mixing cationic surfactants with an inorganic

precursor in aqueous solutions (Beck et al., 1992). After calcination, the organic phase is


2 Prosiding of Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

pyrolyzed and the remaining mesoporous inorganic phase contains periodic nanometer

size pores that are either hexagonally (MCM-41) or cubically arranged (MCM-48). Most

of the mesoporous molecular sieves made thus far have been aluminosilicates or silicates.

The Si and Al sources for these mesoporous materials include sodium silicate,

tetraethoxysilane, colloidal silica, Catapal alumina, and sodium aluminate (Zhao et al.,

1996). The wide variety of silicate and aluminate precursors used to form mesoporous

materials indicates that the formation is not sensitive to the Si and Al sources.

Fly ash, which is a byproduct of coal burning, contains mostly aluminosilicates. Recently,

several authors have studied the conversion of fly ash into zeolites. Shigemoto et al.

(1993) increased the yield of zeolites by fusion of the fly ash with NaOH. The reaction of

fly ash with NaOH produced a large amount of sodium silicates which dissolve readily in

aqueous solutions. In fact, the fusion of silicates and aluminosilicates with alkali-metal

hydroxide has been a common technique for dissolving Si, Al, and many metallic species

for chemical analysis. More recently, Chang and Shih (1998) applied the fusion method

for converting a variety of fly ashes from several power plants to zeolites.

Zeolites are very useful materials for a wide range of applications such as molecular

sieves, adsorbents, ion exchangers, and catalysts. Due to their micropore size, the

application of zeolites becomes inadequate when reactants with size above the

dimensions of the pores (mesopores) have to be processed. Therefore, attempts to enlarge

the pore size of the zeolites from micropore into mesopore region in response to the

increasing demands in both industrial and fundamental studies are promising.

The uniform molecular pore sizes and high specific surface areas of mesoporous

materials can be very useful for a wide range of applications such as molecular sieves,

adsorbents, and catalysts. Therefore, converting fly ash into mesoporous materials not

only eliminates the disposal problem of fly ash but also turns an otherwise waste material

into a useful one. Because fly ash contains a significant amount of aluminosilicates and a

small amount of various metal oxides, the formation of mesoporous phase from fly ash is

not as straightforward as in the case with pure chemicals.

The synthesis of MCM-41 from fly ash was carried out by fusion with NaOH prior to

hydrothermal reaction. Shigemoto et al. (1993) increased the yield of zeolites by first

fusing the fly ash with NaOH. The reaction of fly ash with larger NaOH produced a

larger amount of sodium silicates and aluminates which dissolve readily in aqueous



solutions. The influence of Na concentration becomes important, perhaps more important

than in the case with pure chemical precursors. Although it is known that a high Na

content enhances the formation of zeolites, there is no systematic data concerning the

influence of Na on the formation of the MCM-41 phase. The alkaline fusion was also

used to generate the Si and Al components of volclay (a low-cost sodium exchanged

smectite) which were effectively transformed into mesoporous Al-MCM-41 depending

on hydrothermal condition (Adjdir et al, 2009). Therefore, the weight ratio of NaOH/fly

ash in the fusion pretreatment is crucial in the synthesis of MCM-41 from fly ash.

In the synthesis of MCM-41, the concentration of OH- affected the crystallinity of the

results (Namba et al., 1998). According to the influence of pH on the synthesis of MCM-

41 from pure materials, it was reported that in alkaline solution the increase of pH

resulted MCM-41 with lower crystallinity. Kim et al. (1995) and Ryoo and Kim (1995)

reported the synthesis of MCM-41 from pure materials at pH 10.2 and 11, respectively.

However, Chang et al. (1999) reported synthesis of MCM-41 from fly ash at pH 12.8.

Influence of synthesis pH on the synthesis of MCM-41 from coal fly ash by a green

approach has also been performed (Hui and Chao, 2006). The experimental results

showed that samples synthesized at high pH values had a larger pore size. Therefore, pH

optimization in the synthesis of MCM-41 from fly ash is still essential.

Previously, Chen et al. (1993a) showed that MCM-41 aluminosilicate can only be

prepared with a Si/Al molar ratio higher than 29 using CTAB surfactant. The Si/Al mol

ratio of fly ash sample from Suralaya Power Plant, Serang-Banten, Indonesia was only

1.5. It seems that the Si/Al mol ratio of fly ash is no longer enough in synthesis of MCM-

41 aluminosilicates. The removal of surfactant from MCM-41 was examined by infrared

spectroscopy (Sutarno et al., 2001). Further, the influence of Si/Al mol ratio and

surfactant/Si mol ratio in the precursor solution in the synthesis of MCM-41 from fly ash

has been previously reported (Sutarno et al., 2003; Sutarno et al., 2004). This paper

reported the influence of NaOH/fly ash weight ratio and pH of precursor solution in the

hydrothermal synthesis of mesoporous MCM-41 materials from fly ash.

EXPERIMENTAL METHODS

Materials

The fly ash sample was taken from Suralaya Power Plant, Serang-Banten, Indonesia.

Other chemicals used were sodium hydroxide pellets (Merck, Germany), sodium silicate



(25.5-28.5% SiO2 and 7.5-8.5% Na2O; Merck), tetramethylammonium hydroxide

(TMAOH, Merck), cetyltrimethylammonium bromide (CTAB, Merck), IRA-400 resin

(Sigma), and distilled water (laboratory made).

Synthesis of MCM-41

Synthesis of MCM-41 from fly ash consists of fusion treatment and hydrothermal

reaction. Fly ash was mixed with water and stirred magnetically, the magnetic

components attached to magnetic bar. Because larger amounts of Si and Al species can

be dissolved by the fusion method, therefore it was adopted to dissolve Si and Al species

from fly ash.

The fusion process began by mixing fly ash with NaOH pellets (the weight ratio of

NaOH to fly ash was varied i.e. 0.8, 1.0, 1.2, and 1.4). The mixture was milled and the

mixed powders were heated in a nickel crucible at 550C for 1 hour in air. After fusion,

the resultant fused-fly ash was cooled to room temperature and milled again. The powder

was mixed with water in a weight ratio of 0.20 to produce the fused fly ash solutions. The

fused fly ash solutions were aged for 1 day at room temperature and ambient pressure

with stirring. The fused fly ash did not dissolve completely after 1 day of aging. The

supernatant of the solution was separated from the sediment by centrifugation. The

chemical compositions of supernatant are measured by UV-Vis spectrometer (Hitachi

150-20 UV-Visible) and atomic absorption spectrometer (Nippon Jarrel Ash AA782).

The surfactant solution of 29 wt% CTAB was prepared by mixing 26.1 g of CTAB and

63.9 g of distilled water at room temperature. The CTAOH solution was prepared by

batch exchange of a 29 wt% CTAB solution with IRA-400(OH) exchange resin. The

precursor solution was made by mixing supernatant and sodium silicate solution (the

volume composition of supernatant and sodium silicate solution was varied but the total

volume remained constant 55 mL), 35 mL CTAOH surfactant, and 10 mL TMAOH in a

Teflon beaker.

The mixture was stirred magnetically for 1 hour. The pH value of the precursor solution

was varied, i.e.: 9, 10, 11, and 12 by adding sulfuric acid (1:1 v/v). The mixed solutions

were then hydrothermally heated in stainless steel autoclave with Teflon beaker inside

under autogenous pressure at 100oC for 72 hours without any stirring. After cooling to

room temperature, the resulting solid product was recovered by filtration on a Buchner



funnel, washed repeatedly with water and dried in an oven at 80oC overnight. The as-

synthesized products were then calcined at 550oC with a heating rate of 2C/minute for 1

hour in flowing nitrogen followed by 6 hours in flowing air.

Characterization

The structure of the powders was studied by X-ray diffraction (XRD) using ground

powders, and the surface area measurements were done by a surface area analyzer.

The chemical compositions of the fly ash and the products materials were determined by

chemical analysis. Silicon and Al were measured by UV-Vis spectrometer (Hitachi 150-

20 UV-Visible) whereas Na was measured by atomic absorption spectrometer (Nippon

Jarrel Ash AA782).

X-ray diffraction (XRD) patterns were obtained by powder method using Ni-filtered

CuK radiation at 40 kV and 30 mA with scanning speed of 2o/minute (Shimadzu XRD-

6000). Samples were normally scanned in the 2 range of 1 to 10o. Nitrogen

adsorption measurements were performed on a NOVA 1000 microanalyzer

(QUANTACHROME) at liquid nitrogen temperature. The selected samples were

normally outgassed at 200oC for at least 4 hours under vacuum (104 torr). The samples

were then subjected to automatic analysis.

RESULTS AND DISCUSSION

Synthesis of MCM-41 from fly ash consists of two main steps, i.e. fusion of fly ash and

followed by hydrothermal reaction. Fly ash was fused using NaOH with various weight

ratio of NaOH/fly ash at 550 oC for 1 hour. It has been reported (Sutarno et al., 1999) that

a large amount of sodium silicate exists in the fused fly ash without any initial crystalline

phases, indicating that fusion was very effective in extracting Si species in the fly ash.

The fused fly ash was mixed with water and then aged for 1 day at room temperature.

The supernatant of the solution was separated from the sediment by centrifugation.

Influence of NaOH/fly ash weight ratio on the formation of MCM-41

Concentrations of Si, Al, and Na in supernatant of fly ash solution fused with various

NaOH/fly ash weight ratios were presented in Table 1. On the other hand, the NaOH

used in fusion will also affect the alkalinity (pH) of the solution of reaction mixture and

hence affect the ability of condensation of the Si and Al species to form zeolite materials.



It can be seen in Table 1 that increasing NaOH/fly ash weight ratios resulted in the

higher concentrations of Na in supernatant. In all samples, the concentrations of Si were

higher than the concentrations of Al. Although the influence of NaOH/fly ash weight

ratios on the dissolution of Si and Al were not regular, however, in general it can be seen

that the higher of NaOH/fly ash weight ratios increased the dissolution of Si and Al. In

the formation of mesoporous materials, 35 mL supernatant of fly ash solution fused with

various NaOH/fly ash weight ratios was added with 20 mL sodium silicate. The

surfactants used were also similar, i.e. 35 mL CTAOH and 10 mL TMAOH. Therefore,

each reaction mixture with different NaOH/fly ash weight ratios showed different Si/Al

mol ratios and Sur/Si mol ratios as well as Na concentrations as shown in Table 1.

Table 1. Concentrations of Na, Si, and Al in supernatant of fly ash solution fused with

various NaOH/fly ash weight ratios

NaOH/fly ash weight ratio

Na (g/L)

Si (g/L)

Al (g/L)

Si/Al mol ratio of supernatant

0.8 35,152 4,782 1,249 3.68 1.0 39,177 4,026 985 4.08 1.2 43,202 6,317 1,603 3.79 1.4 47,227 5,283 3,000 1.69

Sodium silicate a 95,260 38,976 - - a Sodium silicate (25.5-28.5% SiO2; 7.5-8.5% Na2O)

In the synthesis system, the gel pH was adjusted by adding sulfuric acid (1:1). The

reaction temperature and time were fixed at about 100 oC and 72 hours, respectively.

Figure 1 shows XRD patterns of as-synthesized products from fly ash prepared with

various NaOH/fly ash weight ratios. XRD patterns of the as-synthesized samples in

Figure 1 revealed a high intensity of first peak and other following peaks consistent with

hexagonal hk0 indexing. The mesoporous MCM-41 obtained allowed identification of the

peaks to the (100), (110), and (200) planes corresponding to a hexagonal structure. The

first XRD peaks related to (100) plane was seen to be more intense for samples under

investigated. According to Ryoo et al. (1999) it can be interpreted as an indication of

higher ordering of the mesopore channel.

Hydrothermal Synthesis of Mesoporous Mcm

Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Figure 1. XRD patterns of as-synthesized products from fly ash prepared NaOH/fly ash weight ratios

Table 2. XRD parameter of MCM-41 samples from fly ash synthesized with various

NaOH/fly ash weight ratios

NaOH/fly ash weight

ratio

Si/Al mol ratio of

precursor

Sur/Si mol ratio of

precursor

0.8 21 1.16 1.0 27 1.20 1.2 17 1.10 1.4 9 1.14

a Due to unavailability of commercial MCMreference of 100% crystallinity

b The wall thickness of MCM-41 is approximately constant at about 1 nm (Feuston Higgins, 1994; Chen et al., 1993b) and D

In general, the materials synthesized with higher NaOH/fly ash weight ratio exhibit

broader and slightly less intense XRD peaks, suggesting that within the higher NaOH/fly

ash weight ratios, the hexagonal arrangement was less ordered compared to the lower

one. The lower NaOH/fly ash weight ratio also resulted in the lower amount of Na in the

synthesis system (Table 1), which the interaction of the surfactant and silicate species


7 Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

synthesized products from fly ash prepared with various

41 samples from fly ash synthesized with various

Sur/Si mol ratio of

precursor

Relative crystallinity

(%) a d100 (nm)

a0 (nm)

DXRD (nm) b

100 4.17 4.79 3.79 77.33 4.12 4.75 3.75 83.14 4.21 4.86 3.86 97.13 4.29 4.95 3.95

Due to unavailability of commercial MCM-41, the highest total intensity is used as

41 is approximately constant at about 1 nm (Feuston and ., 1993b) and DXRD = a0 (nm)-1nm

In general, the materials synthesized with higher NaOH/fly ash weight ratio exhibit

slightly less intense XRD peaks, suggesting that within the higher NaOH/fly

ash weight ratios, the hexagonal arrangement was less ordered compared to the lower

one. The lower NaOH/fly ash weight ratio also resulted in the lower amount of Na in the

), which the interaction of the surfactant and silicate species



seems to be more effective and hence resulted more ordered MCM-41 as indicated by the

crystallinity presented in Table 2.

The lattice constant (a0) of the hexagonal pore arrangement was calculated from XRD

data using the formula: a0=2d100/3 (Chatterjee et al., 2000). The majority of authors

consider that the pore wall thickness of MCM-41 is approximately constant at about 1 nm

and used this value to calculate the pore diameter from (100) diffraction in XRD pattern

(Feuston and Higgins, 1994; Chen et al., 1993b), therefore, pore diameter can be

calculated. The values of a0 for MCM-41 from fly ash fused with various NaOH/fly ash

weight ratios were summarized in Table 2.

The increase of a0 with the higher NaOH/fly ash weight ratios may be also caused by the

Si/Al mol ratio in the precursor solution. According to Table 2, the increase of NaOH/fly

ash weight ratios in general also decreased the Si/Al mol ratio in the precursor solution

without significantly changed the Sur/Si mol ratio. Decreasing the Si/Al mol ratio in the

precursor solution caused more Al in the aluminosilicate framework that will increase a0

due to longer Al-O bonds than Si-O bonds. The detail influence of Si/Al mol ratio on the

formation of MCM-41from fly ash has been reported earlier (Sutarno et al., 2003).

Influence of pH on the formation of MCM-41

In the formation of MCM-41, pH plays a key role in both micelle formation and silicate

polymerization. The XRD patterns of MCM-41 synthesized at various pH systems were

shown in Figure 2. Due to difficulties in adjusting the pH value, the synthesis at pH

lower than 9 could not be performed. It can be seen in Figure 2 that MCM-41 could be

resulted at pH 11-9. However, in a high-pH medium where the pH was around 12, no

ordered phases could be found, the XRD pattern was featureless. According to Vartuli et

al. (1994), in a very high pH medium, condensed phase such as cubic octamer

[(CTA)SiO2.5]8 was detected. On the other hand, in a neutral medium where the pH was

around 7, no ordered phases could be found. This is expected since Si source has to be

dissolved into the system in order to react with surfactant micelles. In a neutral system,

the dissolving rate of Si source is quite slow (Swaddle et al., 1995), and therefore

inorganic/organic assembly is very slow.

Hydrothermal Synthesis of Mesoporous Mcm

Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

Figure 2. XRD patterns of as-synthesized products from fly ash pH systems

Table 3. XRD parameter of MCM-41 samples from fly ashsystems

pH Relative crystallinity (%) a

9 100 10 95.04 11 54.67 12 -

a Due to unavailability of commercial MCMreference of 100% crystallinity

b The wall thickness of MCM-41 is approximately constant at about 1 nm (Feuston Higgins, 1994; Chen et al., 1993b) and D

MCM-41 can be synthesized in an alkaline system (Beck

1992). According to Swaddle et al. (1995), the pH of the solution of reaction mixture

influences the ability of condensation of the Si and Al species to form zeolite materials.

Table 3 showed that as the pH increased, the crystallinity of MCM

significantly. The pH adjustment influenced the mesophase

takes place cooperatively between the silica source and surfactant. The size of the silicate

species increases with decreasing pH, and consequently at low pH (pH 9), the

combination of large silicate species with the small head of CTA

formation of a large head group that is suitable for the hexagonal mesophase and hence

increased the crystallinity. This result was in well agreement with the result of Ryoo

al. (1999).


9 Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

synthesized products from fly ash prepared with various

41 samples from fly ash synthesized with various pH

d100 (nm) a0 (nm) DXRD (nm) b

4.43 5.11 4.11 4.38 5.06 4.06 4.31 4.98 3.98

- - - Due to unavailability of commercial MCM-41, the highest total intensity is used as

41 is approximately constant at about 1 nm (Feuston and ., 1993b) and DXRD = a0 (nm)-1nm

41 can be synthesized in an alkaline system (Beck et al., 1992; Kresge et al.,

(1995), the pH of the solution of reaction mixture

influences the ability of condensation of the Si and Al species to form zeolite materials.

showed that as the pH increased, the crystallinity of MCM-41 decreased

significantly. The pH adjustment influenced the mesophase-formation mechanism that

takes place cooperatively between the silica source and surfactant. The size of the silicate

increases with decreasing pH, and consequently at low pH (pH 9), the

combination of large silicate species with the small head of CTA+ surfactant leads to the

formation of a large head group that is suitable for the hexagonal mesophase and hence

the crystallinity. This result was in well agreement with the result of Ryoo et



It was shown in Table 3 that a0 decreased from 5.11 (pH 9) to 4.98 (pH 11). At higher

pH, silicate species favors the formation of monomer and small oligomer and hence

formed a smaller lattice constant. It has been reported that the distribution of silicate

species is sensitive to pH, temperature, cation, and Si concentration (Kinrade and

Swaddle, 1988). A reduction in Si concentration or increase in temperature or pH favors

the formation of monomer and small oligomers.

Based on the crystallinity of MCM-41 obtained at various pH presented in table 4.4, it

revealed that concentration of Na ions in the precursor solution was not critical in the

hydrothermal synthesis of MCM-41. This result was in contrast with the result of Chang

et al. (1999) in which MCM-41 from fly ash could only synthesized with Na

concentration in the order of 10,000 g/L. In this investigation, although hydrothermal

reaction was conducted with much higher Na concentration (the concentration of Na in

supernatant prepared with NaOH/fly ash weight ratio of 1.2 was 43,202 g/L as

presented in table 4.2), MCM-41 was still clearly formed. Moreover, decreasing pH

significantly increased the crystallinity of the MCM-41 obtained. This result confirmed

that under controlled condition of pH, concentration of Na ions in the precursor solution

was not critical in the hydrothermal synthesis of MCM-41.

Nitrogen adsorption

The nitrogen adsorption isotherms of calcined MCM-41 samples are shown in Figure 3.

It can be seen that MCM-41 samples show type IV isotherms according to the IUPAC

definition (Beck et al., 1992; Kresge et al., 1992). Four steps can be seen on the

isotherms. Step A, a monolayer-mutilayer adsorption process rather than micropore

filling can be seen, which increased sharply with increasing relative pressures. Step B,

capillary condensation process, exhibits a sharp increase in the adsorption amounts. Step

C, adsorption over the external surfaces. Step D, capillary condensation within the

interparticles (macropores).

Included in Table 4 are the BET surface area (SBET) and BJH pore diameter (Dpore)

which was estimated from the adsorption amounts of nitrogen at the relative pressure of

0.95, assuming a full pore filling. It is seen that MCM-41 samples synthesized in

optimum system have a large BET surface area and pore volume. It can also be seen that

the pore diameter calculated from the BJH model was smaller than that estimated from

the XRD data as presented in Table 2. According to Zhu et al. (1998), the

underestimation of the BJH method is due to unstability of the adsorbed notrogen films.



Figure 3. Nitrogen adsorption isotherm calcined MCM-41 synthesized at Si/Al mol ratio in the precursor solution of 23.3 and 44.5

Table 4. BET surface area (SBET), BJH pore diameter (Dpore) of MCM-41 synthesized at Si/Al mol ratio in the precursor solution of 23.3 and 44.5

Si/Al mol ratio in the precursor solution

SBET (m2/g)

DBJH (nm)

23.3 293.3 4.05

44.5 694.5 3.48

Figure 4. Pore size distribution (PSD) of calcined MCM-41 synthesized at Si/Al mol ratio in the precursor solution of 23.3 and 44.5

The narrowed PSDs and no observation of micropores as shown in Figure 4 further

confirmed that the mesophases synthesized in the present work contain pure MCM-41

material without the presence of any microporous and/or amorphous phases. The porosity

is in a good agreement with those previously reported by Beck et al. (1992). The average



pore diameter of MCM-41 synthesized at Si/Al mol ratio in the precursor solution of 23.3

was larger than those of MCM-41 synthesized at Si/Al mol ratio in the precursor solution

of 44.5. However, MCM-41 synthesized at Si/Al mol ratio in the precursor solution of

44.5 showed a narrower distribution (Figure 4) and higher specific surface area (Table 4)

than those of MCM-41 synthesized at Si/Al mol ratio in the precursor solution of 23.3.

CONCLUSIONS

In the hydrothermal synthesis of MCM-41 from fly ash, the lower NaOH/fly ash weight

ratio as well as the lower pH resulted more ordered MCM-41. Although hydrothermal

reaction was conducted under the condition of relatively high Na concentration,

however, MCM-41 could be formed as far as the reaction was conducted under controlled

pH conditions.

ACKNOWLEDGMENTS

The authors would like to thank Mr. Lambert Bekessy from XRD Laboratory, the

University of Queensland for their assistance in recording XRD analyses and Dr. Indriana

Kartini for her kindly assistance in recording nitrogen adsorption (NOVA) analyses at

the University of Queensland.

REFERENCES

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Beck, J.S., Vartuli, C., Roth, W.J., Leonowicz, M. E., Kresge, C. T., Schmitt, K. D., Chu, C. T-W., Olson, D.H., Sheppard, E.W., McCullen, S.B., Higgins, J.B., and Schlenker, J.L., 1992, A New Family of Mesoporous Molecular Sieves Prepared with Liquid Crystal Templates, J. Am. Chem. Soc., 114(27), 10834-10843.

Chandrasekhar, G. and Ahn, W-S., 2008, Synthesis of Cubic Mesoporous Silica and Carbon Using Fly Ash, J. Non-Crystal. Solids, 354(33), 4027-4030.

Chang, H-L., and Shih, W-H., 1998, A General Method for the Conversion of Fly Ash into Zeolites as Ion Exchangers for Cesium, Ind. Eng. Chem. Res., 37, 71-78.

Chang, H-L., Chun C-M., Aksay, I.A., and Shih, W-H., 1999, Conversion of Fly Ash into Mesoporous Aluminosilicate, Ind. Eng. Chem. Res., 38, 937-977.

Chatterjee, M., Iwasaki, T., Onodera, Y., Nagase, T., Hayashi, H., and Ebina, T., 2000,



Characterization of Ordered Mesoporous Gallium MCM-41 Synthesized at Room Temperature, Chem. Mater., 12, 1654-1659.

Chen, C. Y., Li, H. Y., Davis, M. E., 1993a, Studies on Mesoporous Materials I: Synthesis and Characterization of MCM-41, Micropor. Mater., 2, 17-26.

Chen, C-Y., Li, H-Y., and Davis, M.E., 1993b, Studies on Mesoporous Materials II: Synthesis and Mechanism of MCM-41, Micropor. Mater., 2, 27.

Feuston, B.P., and Higgins, J.B., 1994, Physical Sorption of Argon, Nitrogen and Oxygen by MCM-41, a Model Mesoporous Adsorbent, J. Phys. Chem., 98, 4459-4462.

Hui, K. S. and Chao, C. Y. H., 2006, Synthesis of MCM-41 from Coal Fly Ash by a Green Approach: Influence of Synthesis pH, J. Hazard. Mater., 137(2), 1135-48.

Kim, J.M., Kwak, J.H., Jun, S., and Ryoo, R., 1995, Ion Exchange and Thermal Stability of MCM-41, J. Phys. Chem., 99, 16742-16747.

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Kresge, C.T., Leonowicz, M.E., Roth, W.J., Lovell, M. R., and Muir, J. E., 1992, Ordered Mesoporous Molecular Sieves Synthesized by a Liquid-Crystal Template Mechanism, Nature, 710-712.

Majchrzak-Kucba,I. M., Nowak,W., and ciubido, A. , 2009, Studies on the Properties of Mesoporous Materials Derived from Polish Fly Ashes, International Pittsburgh Coal Conference, Pittsburgh, USA, September 21 24, 2009.

Misran , H., Singh, R., Beguma, S., and Yarmob, M.A., 2007, Processing of Mesoporous Silica Materials (MCM-41) from Coal Fly Ash, J. Mater. Process. Technol., 186, 813.

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Sutarno, Arryanto, Y., Setiaji, B., and Sastrohamidjojo, H., Removal of Surfactant from Mesoporous Aluminosilicates Synthesized from Fly Ash, International Seminar on Organic Chemistry, Chemistry Department, Gadjah Mada University, Yogyakarta, 8 September 2001.

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Anion Exchange Capacity of Chromate on Modified Zeolite Clinoptilolite with Hdtma-Br and Its Regeneration


ANION EXCHANGE CAPACITY of CHROMATE on MODIFIED ZEOLITE CLINOPTILOLITE with HDTMA-Br

and ITS REGENERATION

Widajanti Wibowo, Tresye Utari, Rika Tri Yunarti

Department of Chemistry Faculty of Mathematics and Natural Sciences, University of Indonesia

Campus Depok, Depok 16424, Indonesia E-mail : [email protected]

ABSTRACT

Zeolite Clinoptilolite from Lampung, located in South of Sumatra, had been modified with surfactant Hexadecyltrimethylammonium Bromide (HDTMA-Br) for the studies of chromate anion exchange capacity and its regeneration. Surfactant Modified Zeolite (SMZ) Clinoptilolite in particle size range of 1.5 - 2.0 mm, which contained 196.7 mmol HDTMA-Br/kg zeolite, was used for anion exchange of chromate at pH neutral. This experiment was conducted in a glass column filled with 5 gram SMZ. The breakthrough chromate exchange capacity was found 1.262 mg/g SMZ, while the total capacity was found 2.107 mg/g SMZ. The regeneration of SMZ saturated with chromate was conducted using a mixed solutions of 0.28 M Na2CO3 and 0.5 M NaOH, compared with using a solution of 0.01 M Na2S2O4. The desorption of chromate achieved 92% with the mixed solutions of Na2CO3 and NaOH and 90% with the Na2S2O4 solution. The regenerated SMZ with Na2CO3-NaOH solutions was prior washed with HCl solution to remove the carbonate from SMZ, before was used for chromate sorption again. Its breakthrough capacity was reduced to 1.074 mg/g SMZ, and to 0.724 mg/g SMZ when regenerated with Na2S2O4 solution. These results indicated that regeneration of SMZ affected its exchange capacity for anion chromate. However, it is still could be acceptable, when Na2CO3/NaOH solutions were used for the regeneration of SMZ saturated with anion chromate. Keywords : zeolite clinoptilolite ; SMZ ; anion exchange capacity ; chromate ; regeneration

INTRODUCTION In Indonesia, the electroplating industries had grown very fast along with the growing of

automotive industries. Not all of these industries have appropriate waste water treatment,

although the electroplating processes need a lot of water and dispose it as waste water,

especially the water for rinsing processes. In case of chrome electroplating process, its

waste water effluent contains some chromium in hexavalent state, which is more toxic

than the trivalent state and is known to be carcinogenic. This study was aimed to

minimize the low concentration of Cr (VI) in the effluent of rinsing process, which is

usually treated with ion exchange resins. Since the ion exchange resins are expensive, the


16 Prosiding Seminar Nasional Zeolit VI, Terobosan Aplikasi Teknologi Mikro-Nano Zeolit dalam Bidang Industri, Pertanian, dan Lingkungan

development of low cost anion exchange materials based on natural zeolite would be

economically implemented in the chrome electroplating industries.

Zeolites are hydrated aluminosilicate minerals with cage-like framework structure,

consists of AlO45- and SiO4

4- tetrahedra units, which are linked to each other by the

sharing of oxygen atoms. Substitution of each Al3+ to Si4+ in the tetrahedra framework

introduces a net negative charge, which is balanced by the existence of alkali metal or

alkali earth metal cations, such as Na+, K+ and Ca2+, found in the zeolite cavities. These

cations are mobile and can be easily changed by other cations. This makes zeolite

minerals possess a high cation-exchange capacity and are not suitable for anion

contaminants removal in water.

Modification of the negatively charged zeolite surface can be conducted by forming

layers of adsorbed cationic surfactant on the zeolite surface. The sorption of cationic

surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), had been

thermodynamically and kinetically studied [1,2] and it proceeds in two stages. Initially

the cationic surfactant, below its critical micelle concentration (cmc), is adsorbed as a

monolayer by electrostatic effect. The increased of surfactant concentration exceeds its

cmc in the solution will increase the surfactant sorption, caused by the hydrophobic

effect, forming a bilayer of surfactant on the zeolite surface (Fig. 1). Since these

surfactant aggregates look like a micelle structure, this sorption of surfactant on the

zeolite surface is mentioned as admicelle.

Zhaohui Li and co workers studied the chemical and biological stability of HDTMA-

modified zeolite clinoptilolite from the St. Cloud mine in Winston [3] and found some

HDTMA desorption from SMZ in aqueous solution, but less desorption in higher ionic

strength solution. However, HDTMA-modified zeolite has the ability to remove

considerable amounts of chromate from aqueous solution through the anion-exchange

with the counterion Br- [4-8]. Like most sorbents, the uptake of chromate by SMZ

reaches its maximum amount and after that it losses its effectiveness. Regeneration of

chromate-saturated SMZ is therefore needed.



Figure 1 : Adsorption of cationic surfactant on zeolite surface : (b) forming a monolayer of surfactant ; (d) forming a bilayer of surfactant Zhaohui Li and Robert S. Bowman studied the regeneration of chromate-saturated SMZ

with a sodium carbonate/sodium hydroxide solution compared with a sodium dithionite

solution [9] and found that regeneration at high-pH solution of Na2CO3/NaOH decreased

the chromate sorption capacity of the regenerated SMZ.

The aims of this study were to determine the chromate-exchange capacity of HDTMA-

modified clinoptilolite and its breakthrough capacities after regenerated with a solution

of Na2CO3/NaOH compared to with a Na2S2O4 solution.

MATERIALS AND METHODS

The natural zeolite clinoptilolite used for this studies was obtained from CV Mina Tama,

Bandar Lampung, Indonesia, which has the commercial trade name ZKK and particle

sizes P-3 between 1.5 mm and 3 mm. It composed of Clinoptilolite 85%, Mordenite 7%

and Monmoroniote, Plaglioglass, Quarz 8%. The chemicals composition was SiO2

72.60%, Al2O3 12.40%, CaO 2.56%, MgO 1.15%, K2O 2.17%, Na2O 0.45%, Fe2O3

1.19%, TiO2 0.16% and LOI 7.40%

Preparation of SMZ-clinoptilolite The natural zeolite Clinoptilolite, before was modified with HDTMA-Br surfactant, was

activated at 350oC for several hours. The modification was conducted by impregnating

(b)

+ +

+

+

+

+

+

+ + + + +

+

+

+

+

+

+

+

+

+ +

+

+

+

+

+

+

+

+

+

+ +

+

+

+

+

+

+

+

+

+

+ +

+

+ + + + + + +

+ + + + + + + +

+ + + + + + + +

(a)

(c) (d)



with HDTMA-Br at critical admicelle concentration. This cac value was determined by

HDTMA-Br adsorption, which was carried out on 2.5 g clinoptilolite with 10 mL

HDTMA-Br solution at varied concentrations ranged between 10 mmol/L and 90

mmol/L. The mixture of zeolite and HDTMA-Br solution was stirred for 8 hours at 25oC

and then was kept for 48 hours. The solid particles were filtered and were dried at 120oC

to obtain surfactant-modified zeolite (SMZ). Furthermore, SMZ was stirred at 25oC for

24 hours in double-distilled water to study the HDTMA-Br leaching from zeolite.

Non-adsorbed HDTMA-Br in the filtrate and the desorbed HDTMA-Br from SMZ-C

were determined by spectrophotometric method using bromophenolblue (BPB) solution.

Determination of non-adsorbed HDTMA-Br 4 mL filtrate which contained around 0.06 mmol/L HDTMA-Br was added with 4 mL

0.03 mmol/L BPB solution in 0.01 M NaOH. The solution was adjusted to pH 8 using 0.1

M buffer phosphate solution and then was diluted to 10 mL. 5 mL of the solution was

extracted with 5 mL chloroform for 20 minutes. The absorbancy of [HDTMA]2BPB

complex in chloroform phase was determined by uv-vis spectrophotometer at maximum

wavelength.

Chromate anion-exchange An experiment was first conducted to determine the optimum chromate anion-

concentration exchanged by SMZ by the following method. 0.5 g SMZ was mixed with

10 mL K2CrO4 solution at concentrations ranging from 40 mg/L to 900 mg/L, and was

stirred for 24 hours. The SMZ was filtered and was centrifuged for 15 minutes. The

amount of chromate anion in the filtrate was determined by first diluting the filtrate until

10 mL, then adding 0.2 mL 1,5-diphenyl carbazide solution in acetone and one drop

concentrate HNO3. The mixture was left standing for 5 minutes until a reddish-violet

color appeared. The absorbancy of chromate-carbazide complex was determined by uv-

vis spectrophotometer at maximum wavelength.

The anion Bromide from SMZ, which was exchanged by anion Chromate, was

qualitatively determined with AgNO3 solution.

The chromate anion-exchange capacity of SMZ was carried out using a mini-column with

5 mm diameter and equipped with a gauge. The column was filled with 5 g of SMZ and a

K2CrO4 solution at optimum concentration was passed through SMZ. Every 5 mL

effluent was collected to determine the chromate concentration, which was not exchanged

by Br-.



0

50

100

150

200

250

0 20 40 60 80 100

Initial [HDTMA-Br] (mmol/L)

Ads

orbe

d H

DT

MA

-Br

(mm

ol/K

g)

Regeneration of SMZ SMZ saturated by chromate anion was regenerated using a mixed solutions of Na2CO3-

NaOH, compared with the regeneration using a Na2S2O4 solution. The regeneration with

the mixed solutions of Na2CO3 and NaOH was carried out at varied concentrations as

followed : 0,28 M Na2CO3 / 0,5 M NaOH ; 0,28 M Na2CO3 / 0,25 M NaOH ; 0,14 M

Na2CO3 / 0,5 M NaOH and 0,14 M Na2CO3 / 0,25 M NaOH. The exchanged chromate

ion was determined in every 5 mL effluent. The regenerated SMZ was washed with

excess solution 0,1 M HCl and was dried at 110oC for several hours. Now the SMZ with

cloride anion was used again for anion-exchange of K2CrO4 to determine its anion-

exchange capacity after one time regeneration.

The same method of regeneration was conducted using 0,01 M Na2S2O4 solution. The

regenerated SMZ without washing with HCl solution was used to determine again its

chromate anion-exchange capacity.

RESULTS AND DISCUSSION

Critical Admicelle Concentration of Clinoptilolite Zeolite has a net negative charge. Since natural zeolite clinoptilolite has cavity dimension

about 4.2-7.2 and HDTMA-Br surfactant has head dimension around 7 , HDTMA+

will be adsorbed on the surface of clinoptilolite. The cmc value of HDTMA-Br surfactant

is 0.9 mmol/L and since the zeolite modification was carried out with HDTMA-Br

concentrations above its cmc value, a bilayer of surfactant molecules was built on the

zeolite surface, which can be seen as the isotherm adsorption curve on Figure 2.

IV

III

II

I

Figure 2 : Isotherm adsorption of HDTMA+ on zeolite clinoptilolite surface.



Figure 2 shows that HDTMA+ had formed admicelle on zeolite surface at initial

concentration of 30 mmol/L and the amount of adsorbed HDTMA+ was 56.172

mmol/Kg. Area IV shows a constant adsorption, in which HDTMA+ achieved its critical

admicelle concentration value at initial concentration of 70 mmol/L and 196.7 mmol/Kg

HDTMA+ was adorbed on zeolite.

The adsorbed of HDTMA+ on zeolite surface was characterized using FTIR analysis (Fig.

3). The desorbed of HDTMA+ from leaching of SMZ in double-distilled water was found

0.116%. This result shows that HDTMA+ is strongly bound to zeolite clinoptilolite.

(a) (b)

Figure 3 : a. Zeolite clinoptilolite b. HDTMA-modified clinoptilolite (SMZ-C)

Chromate anion-exchange on SMZ-Clinoptilolite

HDTMA-Br is a cationic surfactant with the head groups consist of (CH3)3N

+ and

counterion Br-. The bilayer of HDTMA-Br surfactant on zeolite surface provides

positively charge sites of head groups, which are presented to the surrounding solution

and are balanced by counterions. The sorption or exchange of other anion involves the

replacement of the weakly held counterions by more strongly held counterions, such as

the replacement of Br- with anion chromate, which was qualitatively determined with a

AgNO3 solution. Figure 4 shows the chromate anion-exchange on SMZ-clinoptilolite

with the maximum exchange capacity of 2488.9 mg/Kg.



0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300

Conc. of Chromate at equilibrium (mg/L)

Ads

orbe

d C

hrom

ate

anio

n (m

g/K

g)

[K2CrO4]initial = 700 mg/L

Figure 4 : Chromate anion-exchange on SMZ-C Regeneration of SMZ-C saturated with chromate Although chromate anion is strongly bound to HDTMA-modified zeolite, it can still be

replaced by certain oxyanions, which are stronger held by HDTMA+, like carbonate at

high pH and dithionite. In this study, before the regeneration, HDTMA-modified

clinoptilolite packed in a mini-column was first saturated with chromate by passing 8

aliqout of 5 mL 700 mg/L K2CrO4 solution. Using this method, it was found that the total

capacity of SMZ-C was 2.107 mg/g zeolite.

The regenerations of HDTMA-modified clinoptilolite were carried out using varied

concentrations of mixed Na2CO3/NaOH solution at pH 8 and a Na2S2O4 solution. The

results of the desorbed chromate are shown in Table 1. Washing the regenerated SMZ-C

with 0.1M HCl solution is to replace the carbonate counterions with Cl- before it was

again used for chromate anion-exchange. It was not necessary to replace the dithionite

counterions with Cl-.



Table 1 : %-desorption of chromate from SMZ-C.

[Na2CO3] (M) [NaOH] (M) [Na2S2O4] (M) Chromate desrption (%) 0.28 0.50 - 92.0 0.28 0.25 - 90.0 0.14 0.50 - 87.4 0.14 0.25 - 87.4

- - 0.01 90.0 The regenerated HDTMA-modified clinoptilolite with the mix concentration 0.28M

Na2CO3 and 0.50M NaOH and the regenerated with 0.01M Na2S2O4 were again used for

chromate sorption. The breakthrough capacity for both regenerated SMZ-C were

respectively 1.074 mg/g zeolite and 0.724 mg/g zeolite.

CONCLUSIONS

Zeolite clinoptilolite can be modified with cationic surfactant HDTMA-Br by forming

bilayers admicelle sorption of HDTMA-Br on zeolite surface. The adsorbed HDTMA+ at

initial concentration of 70 mmol/L was 196.7 mmol/Kg zeolite. This HDTMA-modified

zeolite clinoptilolite can be used to remove chromate anion from waste effluent with the

breakthrough exchange capacity of 1.262 mg/g SMZ, while the total capacity was 2.107

mg/g SMZ. The regeneration of SMZ saturated with chromate was successfully

conducted with either a mix concentration of 0.28M Na2CO3 and 0.50M NaOH or with

0.01M Na2S2O4. The breakthrough capacities of both regenerated SMZ were 1.074 mg/g

zeolite and 0.724 mg/g zeolite respectively.

ACKNOWLEDGEMENT

Many thanks to the organization committee for the acceptance of this paper to be

presented at SNZ VI 2009 in Bandung.

REFERENCES Sullivan, E.J., J.W. Carey, R.S. Bowman. 1998. Thermodynamics of cationic surfactant

sorption onto natural clinoptilolite. J. of Colloid and Interface Science, 206, 369-380.

Li, Zhaohui. 1999. Sorption kinetics of hexadecyltrimethylammonium on natural clinoptilolite. Langmuir, 15, 6438-6445.

Li, Zhaohui, S. Stephen, R.Y. Zou, R.S. Bowman. 1998. Long-term chemical and biological stability of surfactant-modified zeolite. Environ Sci. Technol., 32, 2628-2632.



Ghiaci, M., R. Kia, A. Abbaspur, F. Seyedeyn-Azad. 2004. Adsorption of chromate by surfactant-modified zeolites and MCM-41 molecular sieve. Separation and Purification Technology, 40, 285-295.

Li, Zhaohui. 1998. Chromate extraction from surfactant-modified zeolite surfaces. J. of Environmental Quality, 27, 240-242.

Li, Zhaohui, R.S. Bowman. 1997. Counterion effects on the sorption of cationic surfactant and chromate on natural clinoptilolite. Environ. Sci. Technol., 31, 2407-2412.

Krishna, B.S., D.S.R. Murty, B.S. Jai Prakash. 2001. Surfactant-modified clay as adsorbent for chromate. Applied Clay Science, 20, 65-71.

Li, Zhaohui. 2004. Influence of solution pH and ionic strength on chromate uptake by surfactant-modified zeolite. J. of Environmental Engineering @ ASCE Feb, 205-208.

Li, Zhaohui, R.S. Bowman. 2000. Regeneration of surfactant-modified zeolite after saturation with chromate and perchloroethylene. Wat. Res., 35, 322-326.

Supandi Suminta and Mardiyanto


CHARACTERIZATION AND MEASUREMENT OF PORE SIZE OF THE FRAMEWORK STRUCTURE OF NATURAL ZEOLITE


Center for Nuclear Industry Material Technology (BATAN) Indonesia Email : [email protected]

ABSTRACT

The Characterization and Measurement of Pore size of the Framework Structure of Natural Zeolite. An Identification of framework mineral structure and pore size of natural zeolit Bayah, Lampung and Malang (Indonesia) was carried out by Reitveld methods. X-ray diffraction intensity of natural zeolit was measured by an X-Ray Diffractometer (XRD) at PTBIN-BATAN. Parameter structure of Mordenite and Clinoptilolite phase refinement were analysed by Rietveld method using RIETAN program and pore size using Crystal Macker program. The refinement of Clinoptilolite and Mordenite phases have been carried out and the results of refinement show that in Bayah and Lampung were Clinoptilolite phase (space group C2/m HEU No.12, Bravais lattice is Base-Centered and crystal system is monoclinic) and lattice parameter are a = 17,73(2) , b = 17,93(1) and c = 7,414(9) and mass fraction clinoptilolite 68 % and mordenite 32 % respectively (Bayah zeolite) and a = 17,69(2) , b = 17,91(1) and c = 7,422(9) and mass fraction clinoptilolite 80 % and mordenite 20 % respectively (Lampung zeolite) and pore size at S10R are 10,685 and at S8R was 8,193 . Clinoptilolites major exchangeable cations. While Malang zeolites phase (space group Cmcm MOR No.63, Bravais lattice is Base-Centered and crystal system is orthorombic) was Mordenite phase and the lattice parameter are a = 18,115(8) , b = 20,520(9) and c = 7,515(2) and mass fraction mordenite 67 % and clinoptilolite 33 % respectively. The pore size at S12R was 11,43 (exchangeunable cations), filled by H2O only and at S8R was 7,730 (exchangeable cations). Material of natural zeolit from Bayah and Lampung have Cation Exchange Capasity (CEC) bigger than Malang (according to results of the framework structure analysis). Keywords : XRD, Cation Exchange Capasity (CEC), mordenite, clinoptilolite, Rietveld methods

INTRODUCTION

What is a Zeolite

Zeolites (Greek, zein, to boil; lithos, a stone) are minerals that have a micro-porous

structure. Using the Greek words which mean stone that boil, this material is called

zeolite. Two kinds of zeolite : Natural and Synthetic and both there are hydrated

aluminosilicates with symmetrically stacked alumina and silica tetrahedral which result in

an open and stable three-dimensional honeycomb structure with a negative charge. The

negative charge within the pores is neutralized by positively charged ions (cation) such as

sodium (Na+), potassium (K+), calsium (Ca 2+), magnesium (Mg2+) and others. These

Characterization and Measurement of Pore Size of The Framework Structure of Natural Zeolite


positive ions are rather loosely and can readily be exchanged for others in a contact

solution.

Zeolites are aluminosilicates crystalline, of the alkali and alkaline earth metals.Their

crystalline framework is arranged in an interconnecting lattice structure. The arrangement

of these elements in a zeolite crystal, creates a porous framework silicate structure with

interconnecting channels that range in size from 6.5 to 12.0 angstroms, depending on the

zeolite mineral. This structure allows zeolites to perform the following functions

consistently within a broad range of chemical and physical environment [1]:

Gas adsorption : the ability to selectively adsorb specific gas molecules

Water adsorption/desorption : the ability to reversibly adsorb/desorb water without

any chemical or physical change in the zeolite matrix.

Ion exchange : the ability to exchange cations in the crystal structure for other

cations such as lead, thallium, cesium or strontium based on the specific exchange

selectivity of the zeolite mineral.

The adsorption functions identified above are accomplished when gas molecules of

different sizes are allowed to pass through the channels, and depending upon the size of

the channel are separated as to size, in a process known as molecular sieving.

Each zeolite mineral has a distinct ion exchange selectivity and capacity. This process

occurs when water molecules can pass through the channels and pores allowing cations

present in the solution to be exchanged for cations in the structure. Several factors must

be considered in this process. These include solution strength, pH, temperature and the

presence of other competing cations in the solution. These factors can affect both the ion

exchange selectivity and capacity of the specific zeolite minerals.

Natural zeolites form where volcanic rocks and ash layers react with alkaline ground

water. Zeolites also crystallized in post-depositional environments over periods ranging

from thousands to millions of years in shallow marine basins. Naturally occurring

zeolites are rarely pure and are contaminated to varying degrees by other minerals,

metals, quarts or other zeolites. For this reason, naturally occurring zeolites are excluded

from many important commercial applications where uniformity and purity are essensial.



Indonesia is an archipelago country which is rich in natural resources including natural

zeolites. More than 50 zeolites deposits have been identified distributed mainly in

Sumatra, Java, Banten, Sulawesi, Nusa Tenggara, Maluku and Irian Jaya. Some of the

more common mineral zeolites (heulandite, mordenite, charbazite, natrolite, analcime and

philipsite) which are generally considered to be significant for industri, only mordenite

and clinoptilolite are found in Indonesia so far.The two minerals are found together in

varied proportion. In general, mordenite is more dominant than clinoptilolite, especially

in Java, but in Sumatra it was different, clinoptilolite is more dominant in comparison to

Java.

The application of natural zeolite is well known for example as nutrient holders for

agriculture and heavy metals filtration system as part of industrial waste water treatment.

This is due to the most important properties of natural zeolites which possess cation

exchange capacity (CEC), capability to capture ion, as well as to absorp gas and water

molecules.

Framework structure of clinoptilolite and mordenite phases in natural zeolite from Bayah

have been successfully analysed using Rietveld method (accurate method). The

diffraction intensity data were collected using XRD at PTBIN-BATAN. The refinement

of clinoptilolite and mordernite phases have been carried out and the result shows the

clinoptilolite phase is more dominant than mordenite [2]. Bayah zeolite has also been

investigated in many laboratories and the result show that mordenite is more dominant

than clinoptilolite. In this experiment, the intensity of the different pattern is obtained

and characterization of this experiment by using XRD analysed by Hanawalt method

(not accurate method) [3]. From two experiments above they have show different results

due to the different analysis method. Mordenite has similar pattern with clinoptilolite or

silica-rich heundalite, so that it is difficult to determine them exactly by using

conventional Hanawalf method. The determination should be treated with full caution

[4]. Selectivity of Lampung zeolite towards some matrix cations generated from uranium

fission product has been investigated by using some typical fission product-non-

radioactive cation with cation-exchange batch-system process. The previous investigation

showed that Lampung zeolite is effectively able to absorb cesium ion from radioactive

waste. The presence of other cations may affect the zeolite selectivity on to Cs-

exchanges, i.e Cs-exchange capacity of zeolite would decrease in order to Cs>Ba = Sr>

Ce [5].



The objectives of these experiments are to determine the crystal structure phase, pore

size, and cation exchange capacity (CEC) of the framework structure crystal, and

elements that are carried by the natural zeolites from different area to allow appropriate

treatment and final utilization of the natural zeolites. Hence, the experiments will also

involve treatments to activate the natural zeolites that should improve its efficiency and

capacity in capturing heavy metals and increase its molecular sieving capability of

industrial waste water from industries such as papers and textile industries. The

purification and activation of natural zeolites which will be used in the industrial waste

treatment will also be carried out and is expected to give same positive yields and, hence,

creating some benefits to maximize the Indonesia natural zeolites utilization.

EXPERIMENTAL

Activation by heating at 400 oC

Natural zeolite from Bayah (Banten), Lampung (South Sumatra) and Malang (East Java)

were used. natural zeolite was ground and sieved to 50 and 60 mesh. The materials was

heated at 400 oC overnight and during the heating process, air was flowed to remove the

hydrocarbon residue.

Purification treatments

The natural zeolite powder (50 mesh) and aquadest was mixed at room temperature with

appropriate amount of materials needed to obtain total weight of 500 grams i.e : The

aquadest (500 g) was added to the natural zeolit powder (500 g) in the beaker glass (2 l)

and shake until mixed homogenly. The obtained mixture was transfered to Erlenmeyer

flask (capacity 2 l). The flasks was attached to a reflux condenser and heated up at 100 oC for 8 hours on the muntle hot plate and repeated until three times. After finishing the

treatment, the solid was dried at 110oC overnight. The solid was extracted with methyl

iodine (CH3I), and separated from material weight fraction, such as quartz, feldspar,

metals or other minerals. The weight material precipitated and zeolite was floated on

methyl iodide. The solid was heated up at 40 oC until CH3I disappear and the sample

was ready to be characterized.

Characterisation of natural zeolit, includes :

Identification of mineral by XRD and SEM-EDS.

XRD powder patterns were recorded using Shimadzu Intrument Type ZD-610 at

PTBIN-BATAN Indonesia, with Co-K- radiation (30 KV and 30 mA, =



1.788965). The patterns were recorded from 5o to 50o (2) in steps of 0.02 and a

count time of 1 secon at each point.

Analysis of chemical composition by AAS and SEM-EDS

Framework Crystal Structure Analysis of natural zeolite Mordenite and Clinoptilolite

phase by Rietveld method using RIETAN

Pore size and cation exchange capacity (CEC) by Crystal Maker

Refinement of Clinoptilolite and Mordenite phases

Structural parameters of mordenite and clinoptilolite phases of natural zeolits were

refined by Rietveld method using RIETAN program [6].

Clinoptilolite and Mordenite phase refinement were carried out by assuming that Bayah

and Lampung zeolite form were poly-cation as a clinoptilolite phase and structure

parameters data : space group C2/m HEU (No. 12), crystal system monoclinic, lattice

parameters (ngstrom or degree) : a = 17,662, b = 17,911 dan c = 7,407 , and : =

90,0, = 116,4 dan = 90,0o, and atom position data given from reference [7]. Malang

zeolite form was poly- cation as a mordenite phase and structure parameters data :

space group Cmcm MOR (No. 63), crystal system Ortorombik, lattice parameters

(Angstrom or degree) : a = 18,11, b = 20,53 dan c = 7,528 , and : = 90,0, = 90,0

dan = 90,0o, and atom position data given from reference [8].

RESULTS AND DISCUSION

AAS and SEM-EDS Analysis

The chemical composition of Malangs, Bayahs and Lampungs zeolite is depicted in

Table 1.



Table 1. Chemical composition of Malangs, Bayahs and Lampungs zeolite

Consentration (Wt %) Composation Malang Bayah Lampung

SiO2 Al2O3 Fe2O3 MnO TiO P2O5 CaO M

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