Mechanism of zeolite synthesis from coal fly ash by alkali hydrothermal reaction

Murayama, Norihiro; Yamamoto, Hideki; Shibata, Junji

doi:10.1016/s0301-7516(01)00046-1

Cited by 413 publications

(227 citation statements)

References 2 publications

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“…In the zeolite synthesis process, the dissolving rate of Si increased with time at the early stage but reached a plateau value at certain point. Comparatively, the dissolving rate of Al increased for a longer time at the early stage but decreased after reaching a maximum value [8]. Thus, the SiO 2 /Al 2 O 3 ratio was >2 at the early stage (Table 1) to promote the formation zeolite X, and then Si concentration became constant, while Al concentration still increased resulting in a lower SiO 2 /Al 2 O 3 around 14 h to promote the formation zeolite HS.…”

Section: Effect Of Hydrothermal Reaction Timementioning

confidence: 93%

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Effective utilization of waste ash from MSW and coal co-combustion power plant—Zeolite synthesis

Fan

Zhang

Zhu

et al. 2008

Journal of Hazardous Materials

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The solid by-product from power plant fueled with municipal solid waste and coal was used as a raw material to synthesize zeolite by fusionhydrothermal process in order to effectively use this type of waste material. The effects of treatment conditions, including NaOH/ash ratio, operating temperature and hydrothermal reaction time, were investigated, and the product was applied to simulated wastewater treatment. The optimal conditions for zeolite X synthesis were: NaOH/ash ratio = 1.2:1, fusion temperature = 550 • C, crystallization time = 6-10 h and crystallization temperature = 90 • C. In the synthesis process, it was found that zeolite X tended to transform into zeolite HS when NaOH/ash ratio was 1.8 or higher, crystallization time was 14-18 h, operating temperature was 130 • C or higher. The CEC value, BET surface area and pore volume for the synthesized product at optimal conditions were 250 cmol kg −1 , 249 m 2 g −1 and 0.46 cm 3 g −1 respectively, higher than coal fly ash based zeolite. Furthermore, when applied to Zn 2+ contaminated wastewater treatment, the synthesized product presented larger adsorption capacity and bond energy than coal fly ash based zeolite, and the adsorption isotherm data could be well described by Langmuir and Freundlich isotherm models. These results demonstrated that the special type of co-combustion ash from power plant is suitable for synthesizing high quality zeolite, and the products are suitable for heavy metal removal from wastewater.

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Section: Effect Of Hydrothermal Reaction Timementioning

confidence: 93%

“…Many different types of zeolites have been synthesized from various waste ashes such as coal fly ash and MSW incineration ash using hydrothermal or fusion methods [8][9][10]. Zeolites possess the properties of ion exchange, selective adsorption and can be used as molecular sieves.…”

Section: Introductionmentioning

confidence: 99%

Effective utilization of waste ash from MSW and coal co-combustion power plant—Zeolite synthesis

Fan

Zhang

Zhu

et al. 2008

Journal of Hazardous Materials

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“…As zeólitas são aluminossilicatos estruturados em redes cristalinas tridimensionais, compostas de tetraedros do tipo TO 4 (T = Si, Al, Ga, Fe, Ti, etc.). A estrutura da zeólita apresenta canais e cavidades de dimensões moleculares que lhe conferem uma superfície interna extremamente grande em relação a sua massa.…”

Section: Introductionunclassified

“…As cinzas pesadas são constituídas especialmente por óxidos de silício e de alumínio, sendo possível convertê-las em material zeolítico após tratamento hidrotérmico em meio alcalino [4]. As zeólitas caracterizam-se pela alta estabilidade em relação às propriedades de catálise e elevada capacidade de troca catiônica, podendo ser usadas como adsorventes de baixo custo.…”

Section: Introductionunclassified

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Adsorção de nitrogênio amoniacal de efluentes industriais pela zeólita Na-P1 sintetizada a partir da cinza pesada de carvão mineral

et al. 2015

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_____________________________________________________________________________________ RESUMOA legislação ambiental em vigor impõe padrões de emissões cada vez mais restritivos às indústrias geradoras de efluentes. Considerando essas exigências, as empresas precisam se adequar a essas políticas, tornando seus processos produtivos mais eficazes e menos poluentes. A combustão de carvão mineral em usinas termoelétricas gera cinzas pesadas que retornam aos produtores do insumo mineral e constituem um passivo ambiental. Neste estudo, as cinzas pesadas foram utilizadas para testes na síntese hidrotérmica (Hidrogel), em meio alcalino, visando à formação de zeólita Na-P1. Para comprovar a sua efetiva formação, foram realizadas análises por difração de raios X, fluorescência de raios X e capacidade de troca catiônica com solução padrão de cloreto de amônio, cujo valor em termos de equivalentes foi de 23,7 mg g -1 . Os resultados comprovaram a formação da zeólita Na-P1. Foram avaliados três efluentes industriais de três empresas distintas. A concentração final de nitrogênio amoniacal encontrada para os três efluentes após testes de adsorção de amônio em reator de leito fluidizado apresentaram uma redução de 49% ± 2 e os valores obtidos em termos de equivalentes foram de 21,8 mg g -1 , 22,9 mg g -1 e 22,7 mg g -1 . As Resoluções CONAMA 357/2005 430/2011 determinam padrões de qualidade de águas para diversas substâncias; no caso da amônia é de 20 mg L -1 de N/NH 3 . Considerando a grande dificuldade para reduzir os teores de nitrogênio amoniacal em determinados efluentes industriais, novas tecnologias vêm sendo implantadas, como a síntese de zeólitas a partir das cinzas pesadas de carvão. Esse estudo comprovou que a zeólita Na-P1 tem um grande potencial de adsorção para a redução de nitrogênio amoniacal de efluentes industriais.Palavras-chave: zeólita Na-P1, adsorção, nitrogênio amoniacal, efluente industrial. _____________________________________________________________________________________ ABSTRACTEnvironmental legislation in the country always requires more stringent standards for effluent generating industries. Companies must adapt to these laws making the industrial processes more efficient and less polluting. Burning coal in power plants produces bottom ash. This material returns to the coal producers and constitutes an environmental liability to the company. In this study, bottom ash was used in tests for the hydrothermal synthesis, under alkaline conditions, to generate zeolite Na-P1. Analyses by X-ray diffraction, X-ray fluorescence and cation exchange capacity with standard solution of ammonium chloride confirmed to the generation of zeolite Na-P1, and the value of the cation exchange capacity of the equivalent was 23.7 mg g -1 . Three industrial effluents from three different companies were collected and evaluated. Tests for ammonia adsorption in a fluidized bed reactor were performed in the three effluents. The results for the final ammonia concentration showed a reduction of 49% ±2, and the values obtained ar...

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A comparative study on the performance of acid catalysts in the synthesis of levulinate ester using biomass‐derived levulinic acid: a review

Gautam

Barman

Ali

2022

Biofuels Bioprod Bioref

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Non‐renewable resources have adverse effects on the environment, which result in global warming. Research has been shifted toward sustainable resources and lignocellulosic biomass is the best example of this. Lignocellulosic biomass is inexpensive, abundantly available and a rich source of carbon, which makes society less dependant on the use of fossil fuels. It is necessary for society to stop using petroleum‐based technologies and start developing more biomass‐based technologies. Lignocellulosic biomass can be converted into levulinic acid through various methods. Various value‐added chemicals are synthesized from levulinic acid, such as levulinate esters, acrylic acid, β‐acetyl acrylic acid, 1,4‐pentanediol, 2‐methyl tetrahydrofuran, γ‐valerolactone, etc. Among these, levulinate esters have received much attention owing to their broad applications as fuel additives, plasticizers and solvents in the pharmaceutical industries. Levulinate esters can be synthesized from the esterification reaction of levulinic acid and alcohol in the presence of either liquid or solid acid catalysts. Heterogeneous catalysts are favoured above homogeneous catalysts because of their properties, like being easy to separate, having good catalytic activity, being non‐corrosive to the reactor and having good recyclability. The performance of various heterogeneous catalysts such as zirconia, heteropolyacids, zeolite, carbonaceous material, resins and biocatalysts is reported in detail in the review. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd

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Mechanism of zeolite synthesis from coal fly ash by alkali hydrothermal reaction

Cited by 413 publications

References 2 publications

Effective utilization of waste ash from MSW and coal co-combustion power plant—Zeolite synthesis

Effective utilization of waste ash from MSW and coal co-combustion power plant—Zeolite synthesis

Adsorção de nitrogênio amoniacal de efluentes industriais pela zeólita Na-P1 sintetizada a partir da cinza pesada de carvão mineral

A comparative study on the performance of acid catalysts in the synthesis of levulinate ester using biomass‐derived levulinic acid: a review

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