Alkali Hydrothermal Synthesis of Zeolites from Coal Fly Ash and Their Uptake Properties of Cesium Ion

Abstract

Zeolites were synthesized from coal fly ash by hydrothermal treatment with KOH solutions. K-H zeolite (K2Al2Si4O12-nH2O) was produced under optimum conditions of 160°C, 3 d, 1 M (=mol/dm3) KOH and liquid-solid ratio of 15cm3/g. The uptake behavior of radioactive cesium for the products was investigated by batch and column methods. The uptake equilibrium of Cs+ for the above product was attained within 2h yielding the distribution coefficient of above 104 cm3/g. The uptake of Cs+ was followed by a Langmuir adsorption isotherm and the maximum uptake capacity was estimated to be 3.34 mmol/g. The successive removal of Cs+ was accomplished through the column packed with granular composites of product-alginate gel polymer. © 2001 Taylor and Francis Group, LLC.