REMOVAL OF CESIUM FROM AQUEOUS SOLUTION BY ADSORPTION ONTO SİVAS-YILDIZELİ (TURKİYE) VERMICULITE: EQUILIBRIUM, KINETIC AND THERMODYNAMIC STUDIES

Authors : Hilmi Arkut AKALIN, Ümran HİÇSÖNMEZ, Hatice YILMAZ

Pages : 85-116

Doi:10.18596/jotcsa.317771

View : 15 | Download : 10

Publication Date : 2017-09-01

Article Type : Research Paper

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 the optimum adsorption conditons; different adsorbent dosages, contact times, solution pH’s, initial cesium concentrations and temperature ranges were investigated. Amount of cesium ions and percentage of cesium adsorbed by vermiculite in solution media were calculated using ICP-OES technique and noted as mg/g and %adsorbed Cs. Kinetic studies demonstrated that adsorption process was in accordance with second order pseudo kinetic model and equilibrium isotherm modeling studies showed that the process was compatible with Langmuir, Freundlich and Temkin adsorption isotherm models meaning the Cs adsorption process had both phsyical and chemical character. Negative Gibbs energy values obtained from thermodynamic studies revealed that the adsorption process was spontaneous and had a high feasibility. Additionally, negative enthalpy value indicated that process was exothermic, meaning the amount of Cs ions decresead with increasing reaction temperatures and positive entrophy 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.  
Keywords : Cesium, vermiculite, adsorption, adsorption kinetic models, adsorption isotherms