Synthesis of large crystals of ZSM-5 zeolite from a smectite-type clay material

Abdmeziem, K.; Siffert, Bernard

doi:10.1016/0169-1317(94)90038-8

Cited by 22 publications

(10 citation statements)

References 6 publications

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“…3 They are widely used as low cost ion-exchangers and are especially used for the removal of ammonium ions in wastewater treatment. 4 -6 Synthesis of high-quality zeolites by hydrothermal treatment of various materials, such as fly ash, 7 -9 kaolinite, 10 smectite, 11,12 bentonite 13 and natural zeolite, 14,15 has been reported. Kang and Egashira et al have synthesized sodium phillipsite (Na-P) with a trace of feldspar from natural clinoptilolite and mordenite by hydrothermal treatment with 2 M NaOH for 16 h at 103 • C. 14 They have found that when the natural clinoptilolite is treated hydrothermally it changes to Na-P, sodium faujasite (Na-X) and hydroxy-sodalite depending on the reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal modification of natural zeolites to improve uptake of ammonium ions

Watanabe

Yamada

Tanaka

et al. 2005

J of Chemical Tech & Biotech

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The modification of natural zeolites was carried out under hydrothermal conditions to improve the effectiveness of the uptake of ammonium ions. Natural zeolites originating in Japan, such as mordenite and clinoptilolite with quartz, feldspar and a trace of layered silicate, were treated with 0.1, 0.3, 1.0 and 3.0 M NaOH solutions at temperatures from 25 to 150• C under autogenous pressure for 7 days. After the hydrothermal treatment, the transformation of the zeolites to phillipsite, hydroxyl-sodalite and analcime was observed, depending on the temperature and NaOH concentration. The amounts of ammonium ions taken up into the hydrothermally-treated zeolites were compared with those of the starting materials. The treated products, containing mainly phillipsite, took up twice the amount of ammonium ions as the starting materials. The maximum uptake of ammonium ions was 1.92 mmol g −1 . The number of ammonium ions taken up into phillipsite was equal to the number of Na + ions released from phillipsite. These results indicate that the uptake of ammonium ions proceeds by an ion-exchange mechanism with Na + ions.

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Section: Introductionmentioning

confidence: 99%

Hydrothermal modification of natural zeolites to improve uptake of ammonium ions

Watanabe

Yamada

Tanaka

et al. 2005

J of Chemical Tech & Biotech

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“…There have been many studies on synthesizing zeolites from natural minerals, such as smectite (Abdmeziem and Siffert, 1994) Zeolites have been also synthesized from the solid wastes, such as coal fly ash (Shigemoto et al, 1990;Morayama et al, 2002;Querol et al, 2002;Tanaka et al, 2003;Inada et al, 2005;Terzano et al, 2005 in raw material, so to produce the A and X zeolites, it is better to use common zeolites with a comparatively low Si/Al ratio, such as chabazite (Si/Al=3.0), analcime and laumontite (Si/Al=2.0), or phillipsite (Si/Al= 5 / 3 ). Another reason for the impossibility of recrystallization of clinoptilolite in zeolite A may be the fact that the HEU structure has only 4-member ring SBU of 4-4=1 type containing 9 T-atoms, and CBU of bre type containing 10 T-atoms.…”

Section: Issn: 2320-5407mentioning

confidence: 99%

Transformation of Natural Analcime and Phillipsite During Their Hydrothermal Recrystallization Into Zeolites a and X.

Tsitsishvili¹

2019

IJAR

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The objective of the present work was to study transformation of Georgian natural zeolites, analcime and phillipsite, during their recrystallization in the aim to obtain zeolites A and X, widely used for adsorption, separation, ion exchange and catalysis. It is found that phase-pure zeolite NaA (Na 11.25(25) (K,½Ca,½Mg) 0.7(1) (Al 11.95(25) Si 12.3(3) O 48). 18H 2 O) can be prepared in the form of cubic/rhombus crystallites with uniform micrometric (3-5 μm) dimensions by hydrothermal crystallization (95 o C) of aged (72 hr) at room temperature gel (4.5Na 2 O: 0.45Al 2 O 3 : 1SiO 2 : 178H 2 O) obtained from natural analcime, treated with hydrochloric acid before suspending in water and mixing with sodium hydroxide. Phase-pure zeolite NaX (|Na 66(3) [K,½Ca,½Mg,½Cu,½Zn] 12(1) (H 2 O) 248(10) | (Al 78(3) Si 114(4) O 384)) with specific surface area of 589 m 2 /g and total pore volume of 0.578 cm 3 /g can be prepared in the form of octahedral crystallites with uniform micrometric (2-7 μm) dimensions by hydrothermal crystallization (95 o C) of aged (96 hr) at room temperature gel (2.9Na 2 O: 0.26Al 2 O 3 : 1SiO 2 : 150H 2 O) obtained from water suspension of natural phillipsite, treated with hydrochloric acid and mixed with sodium hydroxide. The resulting zeolites in their characteristics are competitive with commercially available materials.

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“…As argilas foram empregadas na sua forma natural; em trabalhos da literatura [14][15][16] constata-se que normalmente se requer que o caulim seja previamente calcinado transformando-se em metacaulim. Acredita-se que na forma meta-caulim se encontre mais reativo e, por isso, mais adequado para a síntese de zeólitas.…”

Section: Figura 3 Difratogramas De Raios-x Dos Materiais Obtidos Pelunclassified

Estudo da síntese da zeólita ZSM-5 a partir de argilas naturais

Mignoni¹,

Detoni²,

Pergher³

2007

Quím. Nova

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Recebido em 20/10/05; aceito em 11/4/06; publicado na web em 22/8/06 STUDY OF ZSM-5 ZEOLITE SYNTHESIS FROM NATURAL CLAYS. The synthesis of ZSM-5 zeolite was studied by three synthesis methods: standard synthesis, three day synthesis and synthesis employing clays (kaolin and montmorillonite). The raw materials and prepared materials were characterized by Chemical Analysis by X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD). The results show that it is possible to synthesized ZSM-5 zeolite using clays as raw materials. Kaolin gives phases of higher crystalinity than montmorillonite.Keywords: ZSM-5; zeolites; clays. INTRODUÇÃOA zeólita ZSM-5 pertence a uma família de zeólitas designadas com as iniciais de sua inventora ZSM ("Zeolite Socony Mobil"), também conhecida como pentasil. Estas zeólitas se caracterizam por apresentarem um alto grau percentual de silício (relação Si/Al compreendida entre 15 e infinito) 1 .Esta zeólita, em função desta relação Si/Al, apresenta os seguintes parâmetros de cela unitária: a = 20,10 -20,07 Å; b = 19,90 -19,86 Å; c = 13,40 -13,36 Å; e tem a seguinte fórmula química:A estrutura apresenta dois sistemas de canais que se entrecruzam, um que é retilíneo e o outro é sinosuidal, aos quais se ingressa por aberturas formadas por dez membros (10MR) de diâmetro cerca de 6 Å 2 (Figura 1).A síntese da zeólita ZSM-5 é bem conhecida na literatura 3-9 . Na síntese destes materiais utilizam-se vários reagentes: sílica, aluminato de sódio, hidróxido de sódio, água, reagente orgânico (template) etc. A síntese é realizada em autoclaves com aquecimento e a cristalização da fase zeolítica leva de uma a duas semanas.Na busca de novas rotas de sínteses de zeólita, é interessante obter as fases zeolíticas em menores tempos e empregando menores quantidades de reagentes orgânicos (viabilidade econômica).O objetivo deste trabalho é estudar e propor novas rotas de sín-tese para a zeólita ZSM-5. Como referência empregaremos a sínte-se padrão 1 e uma síntese proposta com o emprego de álcool como co-direcionador e em menor tempo de síntese 10 ; posteriormente, será proposta uma síntese empregando argilas como fontes alternativas de matérias-primas.Estudou-se também a influência da agitação sobre o processo de cristalização dessa zeólita, uma vez que se conhece a influência deste parâmetro sobre a cristalização do gel 1 . PARTE EXPERIMENTALA síntese da zeólita ZSM-5 foi realizada através de três procedimentos de síntese: síntese padrão 1 , síntese três dias 10 e síntese empregando argilas. Síntese padrãoA Tabela 1 mostra as relações molares dos reagentes empregados para a síntese da zeólita ZSM-5. A partir destas relações molaTabela 2. Quantidades (g) dos reagentes empregados nas sínteses da zeólita ZSM-5

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Synthesis of large crystals of ZSM-5 zeolite from a smectite-type clay material

Cited by 22 publications

References 6 publications

Hydrothermal modification of natural zeolites to improve uptake of ammonium ions

Hydrothermal modification of natural zeolites to improve uptake of ammonium ions

Transformation of Natural Analcime and Phillipsite During Their Hydrothermal Recrystallization Into Zeolites a and X.

Estudo da síntese da zeólita ZSM-5 a partir de argilas naturais

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