Removal of cesium from aqueous solution by adsorption onto sivas-yildizeli (Türkiye) vermiculite: Equilibrium, kinetic and thermodynamic studies

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 the optimum adsorption conditions; different adsorbent dosages, contact times, solution pH’s, initial cesium concentrations and temperature ranges were investigated. The concentration of cesium in solution was determined by ICP-OES. Kinetic studies demonstrated that adsorption process was in accordance with pseudo-second order kinetic model and equilibrium isotherm modeling studies showed that the process was compatible with Langmuir, Freundlich and Temkin adsorption isotherm models, indicating that Cs adsorption process had both physical and chemical character. Negative Gibbs energy values obtained from thermodynamic studies revealed that the adsorption process was spontaneous and had a high feasibility. Additionally, the negative enthalpy value indicated that process was exothermic, suggesting that the adsorbed Cs+ ions decreased with increasing reaction temperatures. Positive entropy value showed that disorderliness between solid-liquid phase increased during adsorption. Results clearly indicate that vermiculite mineral has a promising potential in removing Cs+ ions from aqueous media which leads mineral may also be used in decomposing and efficiently removing radioactive cesium from contaminated waters. © 2018, Turkish Chemical Society. All rights reserved