Behavior and analysis of Cesium adsorption on montmorillonite mineral

The adsorption of Cs by montmorillonite and the effects of experimental conditions on adsorption were investigated by using Cs-134 as a radioactive tracer. Additionally, the Cs-adsorbed and the modified montmorillonite were analyzed by X-ray Diffractometer System (XRD) and Scanning Electron Microscopy (SEM). The results showed that the adsorption of Cs by montmorillonite was efficient in the initial concentration (C-0) of 30 mu g/L Cs nitrate solution with 20 g/L montmorillonite at room temperature. In this condition, more than 98% Cs+ ions could be adsorbed at pH similar to 8. The adsorption equilibrium was achieved within 5 min and the relationship between the concentration of Cs+ in aqueous solutions and adsorption capacities of Cs+ can be described by the Langmuir adsorption isotherm. The adsorption rate would decrease when temperature increase from 0 degrees C to 50 degrees C or in presence of coexistent K+, Na+ and Ca2+, while modification by (NH4)(2)SO4, [Ag(NH3)(2)](+). [Cu(NH3)(4)](2+) or 450 degrees C could improve the adsorption abilities of montmorillonite for Cs'. However, more than 89% of adsorbed Cs+ on montmorillonite could be desorbed by 2 mol/L HNO3 solutions. The XRD and SEM analysis further showed that the structure of the Cs-adsorbed or modified montmorillonite were different from that of the original one. (C) 2009 Published by Elsevier Ltd.