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 (134)Cs 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 microg/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 approximately 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 Ca(2+), while modification by (NH(4))(2)SO(4), [Ag(NH(3))(2)](+), [Cu(NH(3))(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 HNO(3) 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.