Abstract: “The adsorption properties of local bentonite (SemnanIran) and nanobentonite prepared from this bentonite towards Cs+adsorption, were investigated by batch equilibration. The influence of equilibration time, sorption isotherms, kinetic sorption, solution pH and presence of EDTA and NaCl on these properties was studied and discussed. Kinetic data were found to be well fitted with pseudo-second order kinetic model. Cs+ is preferably adsorbed by bentonite and nanobentonite. The Freundlich isotherm model has the best fit with experimental data than other sorption isotherm models. The maximum sorption of Cs+, representing the highest negative charge density on the surface of the adsorbentwas observed at pH 8, where the negative charge density on the surface of the absorbents was the highest. The lowest observed sorption was observed at pH 12.30 for bentonite. Presence of EDTA and NaCldecreased the amount of Cs+ sorptio”

Keywords: bentonite; nanobentonite; Cs+ ; Equilibrium isotherm; Kinetics