Adsorption of Strontium by Vermiculite and Montmorillonite

The adsorption of Sr2+ by vermiculite and montmorillonite and the effects of experimental conditions were investigated.The results show that more than 96.8% and 98.5% of the total Sr2+ can be adsorbed by the vermiculite and montmorillonite from pH=8 Sr2+ solution of 20 MBq/L(C0) at room temperature,respectively.The equilibrium of adsorption by vermiculite and montmorillonite was achieved within 2 h and 15 min severally,and the optimum pH both ranged from 3 to 10.More than 82.7% and 98.7% Sr2+ can be desorbed by 2 mol/L HNO3 solution from the vermiculite and montmorillonite.The adsorption rate of Sr2+ by vermiculite and montmorillonite will decrease in presence of coexistent Ca2+,while modified by [Ag(NH3)2]+ and 1 mol/L HCl can improve the adsorption abilities of vermiculite for Sr2+,but decreased by high temperature.As for montmorillonite,modified by [Cu(NH3)4]2+ can improve adsorption,however,by [Ag(NH3)2]+ and high temperature can decrease.Additionally,the modified vermiculite and montmorillonite were analyzed by X-ray diffractometer system(XRD).The results show that the spectra of the modified vermiculite or montmorillonite are different from that of the original one.