Investigation and Modeling of Cesium(I) Adsorption by Turkish Clays: Bentonite, Zeolite, Sepiolite, and Kaolinite

The cesium ion adsorption by Turkish clays, i.e., bentonite, zeolite, sepiolite, and kaolinite, was investigated as a function of Cs+ concentration, pH, time, and temperature using the Cs-137 radiotracer method. The analysis of some major and minor components of clays was performed with ED-XRF. Bentonite was shown to exhibit the highest capacity and sorption affinity toward Cs. The best fits for adsorption isotherms were with Freundlich and D-R models. The second order rate constant of cesium sorption was highest for kaolinite among the clays. Cesium adsorption proceeded essentially by ion exchange and partly by specific adsorption mechanisms. The results showed that especially bentonite and zeolite can be used as effective barrier materials for sorptive hindrance of an expanding Cs radioisotope plume. (C) 2010 American Institute of Chemical Engineers Environ Prog, 30: 70-80, 201