Alkali hydrothermal synthesis of zeolites from coal fly ash and their uptake properties of cesium ion

Zeolites were synthesized from coal fly ash by hydrothermal treatment with KOH solutions. K-H zeolite (K2Al2Si4O12. nH(2)O) was produced under optimum conditions of 160 degreesC, 3 d, 1 M (=mol/dm(3)) KOH and liquid-solid ratio of 15 cm(3)/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 2 h yielding the distribution coefficient of above 10(4) cm(3)/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.