Zeolite synthesis from coal fly ash by hydrothermal reaction using various alkali sources

Murayama, Norihiro; Yamamoto, Hideki; Shibata, Junji

doi:10.1002/jctb.604

Cited by 53 publications

(36 citation statements)

References 4 publications

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“…The conversion of FA into zeolitic materials through the batch hydrothermal synthesis process involves three stages: (i) dissolution of Al and Si from FA; (ii) deposition of aluminosilicate gel on the FA surface; and (iii) crystallisation of zeolite from aluminosilicate gel . The three Al‐ and Si‐containing phases of the FA are: (i) amorphous aluminosilicate glass; (ii) quartz; and (iii) mullite.…”

Section: Resultsmentioning

confidence: 99%

Powdered Ca‐activated zeolite for phosphate removal from treated waste‐water

Hermassi

Valderrama

Moreno

et al. 2016

J of Chemical Tech & Biotech

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BACKGROUND A powdered zeolitic material synthesised from fly ash (FA) (NaP1‐FA) and its calcium modified form (CaP1‐NA) were studied as sorbent materials for the recovery of phosphate from treated waste‐water effluents. Phosphate‐sorption equilibrium experiments were performed by varying the experimental conditions, including solution pH, phosphate concentration, and the presence of competing ions. RESULTS The maximum phosphate‐sorption capacities were 57 ± 5 and 203 ± 11 mgP–PO4 g−1 for NaP1‐FA and CaP1‐NA, respectively. The sorption capacities of both zeolites in the pH range expected for waste‐water effluents (pH 7 to 9) were slightly dependent on pH, exhibiting maxima at pH 8. Phosphate removal proceeds through two main mechanisms: (a) surface complexation with ≅AlOH and ≅FeOH groups of the zeolitic structure or unreacted minerals from the FA; and (b) the formation of Ca–phosphate phases, mainly brushite. CONCLUSIONS The removal mechanisms were confirmed by XRD analyses and P speciation. The stabilities of the phosphate‐loaded zeolite samples evaluated by the extraction experiments confirmed their potential availabilities in soil applications. Finally, the higher solubility of brushite compared with that of Hap makes this zeolitic material promising as a novel inorganic zeolite/CaP1‐NA/brushite fertiliser. © 2015 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Powdered Ca‐activated zeolite for phosphate removal from treated waste‐water

Hermassi

Valderrama

Moreno

et al. 2016

J of Chemical Tech & Biotech

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“…In contrast, with Na 2 CO 3 , very small and weak XRD peaks of zeolite P were observed because of the low dissolution of CFA in a carbonate solution. 60) Changes in the yield and type of product with changes in NaOH concentration are explained using the solubility of Si and Al in the alkaline solution. Actually, NaOH is a more effective alkaline source for zeolite formation than either Na 2 CO 3 or KOH.…”

Section: Synthesis Of Several Zeolitesmentioning

confidence: 99%

Resource recovery from coal fly ash waste: an overview study

Jha

Matsuda

Miyake

2008

J. Ceram. Soc. Japan

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Coal fly ash (CFA) is a useful byproduct of the combustion of coal. It is composed primarily of almost perfectly spherical aluminosilicate glass particles. This spherical characteristic and other characteristics of CFA should be exploited, rather than simply using CFA as inert filler for construction. Unfortunately, the presence of carbon residues and high levels of heavy metals has so far limited the uses of CFA. Forced leaching methods have been used to improve the technical and environmentally friendly qualities of CFA, but these processes do not seem to be economically viable. Actually, CFA is a major source of Si and Al for the synthesis of industrial minerals. Potential novel uses of CFA, e.g., for the synthesis of ceramic materials, ceramic membrane filters, zeolites, and geopolymers, are reviewed in this article with the intention of exploring new areas that will expand the positive reuse of fly ash, thereby helping to reduce the environmental and economic impacts of CFA disposal.

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“…Many studies [7][8][9][10][11] on the synthesis of zeolite-type materials by hydrothermal treatment using fly ash have been reported. However, the synthesized product is zeolite with high Si/Al ratio and there are only a few reports on the synthesis of zeolite A as a main product.…”

Section: Introductionmentioning

confidence: 99%

Alkali Hydrothermal Synthesis of Zeolite A Using Oxide By-products

et al. 2011

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The alkali hydrothermal synthesis of zeolite A using oxide by-products such as blast furnace (BF) slag and aluminum dross was investigated. Na-P1 (Na 6 Al 6 Si 6 O 32 · 12H 2 O) was synthesized directly in NaOH aqueous solution for 86.4 ks at 373 K using BF slag, Al 2 O 3 , and SiO 2 . On the other hand, zeolite A was successfully synthesized by a two-step method including an elution treatment of Al 2 O 3 . Under optimal conditions, the formation ratio of zeolite A in various compounds contained in the product was 56 %. The utilization of dross residue squeezed out from the aluminum dross as a raw material to synthesis of zeolite A let this ratio increase to 60 %. The heat of water adsorption of the product synthesized by the two-step method using BF slag, SiO 2 , and aluminum dross residue was measured, and it was 184 J/g, being higher than that of commercial zeolite A.

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Zeolite synthesis from coal fly ash by hydrothermal reaction using various alkali sources

Cited by 53 publications

References 4 publications

Powdered Ca‐activated zeolite for phosphate removal from treated waste‐water

Powdered Ca‐activated zeolite for phosphate removal from treated waste‐water

Resource recovery from coal fly ash waste: an overview study

Alkali Hydrothermal Synthesis of Zeolite A Using Oxide By-products

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