Synthesis of high-purity Na-A and Na-X zeolite from coal fly ash

Journal article

Authors/Editors

NAVADOL LAOSIRIPOJANA

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Publication Details

Author list: Panitchakarn P., Laosiripojana N., Viriya-umpikul N., Pavasant P.

Publisher: Taylor and Francis Group

Publication year: 2014

Journal: Journal of the Air & Waste Management Association (1096-2247)

Volume number: 64

Issue number: 5

Start page: 586

End page: 596

Number of pages: 11

ISSN: 1096-2247

eISSN: 2162-2906

URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900323610&doi=10.1080%2f10962247.2013.859184&partnerID=40&md5=9a243a82af006a71d6d2125263c7c457

Languages: English-Great Britain (EN-GB)

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Abstract

Coal fly ash (CFA) was used as a raw material for the synthesis of zeolite molecular sieve. The synthesis began with the pretreatment of CFA to remove impurities (e.g., Fe2O3, CaO, etc.) under various acid types (HCl, H2SO4, and HNO3) and acid/CFA ratios (5-25 mLacid/gCFA). High product purity (up to 97%) was achieved with HCl (20%wt), and acid/CFA ratio of 20 mLHCl/gCFA. The treated CFA was then converted to zeolite by the fusion reaction under various Si/Al molar ratios (0.54-1.84). Zeolite type A was synthesized when the Si/Al molar ratios were lower than 1, whereas sodium aluminum silicate hydrate was formed when the Si/Al molar ratio were higher than 1. The highest water adsorption performance of the zeolite product, i.e., the outlet ethanol concentration of 99.9%wt and the specific adsorption capacity of 2.31 ื 10-2 gwater/gzeolite, was observed with the Si/Al molar ratio of 0.82. The zeolite was tested for its water adsorption capacity repeatedly 10 times without deactivation. This work evaluated the technical feasibility in the conversion of CFA to zeolite, which would help reduce the quantity of waste needed to be landfilled. This adds value to the unwanted material by converting it into something that can be further used. The synthesized products were shown to be quite stable as water adsorbent for the dehydration of ethanol solution. ฉ 2014 A&WMA.

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