Removal of Cesium from Aqueous Solution by Adsorption onto Sivas- Yildizeli (Türkiye) Vermiculite: Equilibrium, Kinetic and Thermodynamic Studies

Abstract

In this study, cesium adsorption performance of raw vermiculite obtained from Sivas-Yıldızeli region of Turkey was investigated using batch adsorption method. In order to obtain theoptimum adsorption conditions; different adsorbent dosages, contact times, solution pH’s, initialcesium concentrations and temperature ranges were investigated. The concentration of cesiumin solution was determined by ICP-OES. Kinetic studies demonstrated that adsorption processwas in accordance with pseudo-second order kinetic model and equilibrium isotherm modelingstudies showed that the process was compatible with Langmuir, Freundlich and Temkinadsorption isotherm models, indicating that Cs adsorption process had both physical andchemical character. Negative Gibbs energy values obtained from thermodynamic studiesrevealed that the adsorption process was spontaneous and had a high feasibility. Additionally,the negative enthalpy value indicated that process was exothermic, suggesting that the adsorbedCs+ ions decreased with increasing reaction temperatures. Positive entropy value showed thatdisorderliness between solid-liquid phase increased during adsorption. Results clearly indicatethat vermiculite mineral has a promising potential in removing Cs+ ions from aqueous mediawhich leads mineral may also be used in decomposing and efficiently removing radioactivecesium from contaminated waters.