Surface spectroscopic studies of Cs+, and Ba2+ sorption on chlorite-illitemixed clay

The sorption behavior of Cs+, and Ba2+ on natural clay was investigated usi ng ToF-SWIS, XPS, and XRD. The natural clay was composed mainly of chlorite and illite in addition to quartz and calcite. Depth profiling up to 70 Ang strom was performed at 10 Angstrom steps utilizing ToF-SIMS to study the am ount of sorbed Cs+ and Ba2+ as a function of depth in the clay matrix. The results suggest that Cs+ and Ba2+ ions were sorbed primarily by ion exchang e coupled with hydrolytic sorption. According to ToF-SIMS and XPS results, the total sorbed amount of Ba2+ was larger than that of Cs+. Quantitative d etermination of the primary cations within the analyzed clay before and aft er sorption indicated that for Ba2+ sorption, Ca2+, Mg2+ and for Cs+ sorpti on Ca2+ K+ were the major exchanging ions. The XRD spectra of Ba-sorbed cla y contained new peaks that were identified as BaCO3.