A comparative study on native and gamma irradiated bentonite for cesium ion uptake

Abstract

The present study aims at understanding the sorption performance of gamma irradiated bentonite clay (Bentoγ) for cesium (Cs) ions as compared to native bentonite (BentoN). BentoN was irradiated up to a dosage of 100 KGy using high intensity 60Co source. The uptake of Cs using both BentoN and Bentoγ clay sorbents was investigated from aqueous medium over a wide concentration range (50–1000 mg L-1) in batch mode and the distribution coefficients for Cs were determined. Batch studies revealed that maximum sorption of cesium occurred within 10 min of contact with the sorbent at a solution pH 6. The sorption data was analyzed using non-linear Langmuir and Freundlich adsorption isotherms. The characterization of bentonite using different physicochemical techniques like SEM, XRD and FTIR illustrated that there were minor structural changes after irradiation. The effect of gamma irradiation on the structural properties of constituent clay minerals of bentonite and the resultant reduction in the sorption capacity of the sorbent has been correlated in order to get an insight into the sorption mechanism.