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

Abstract

The sorption behavior of Cs+, and Ba2+on natural clay was investigated using ToF-SIMS, XPS, and XRD. The natural clay was composed mainly of chlorite and illite in addition to quartz and calcite. Depth profiling up to 70 Å was performed at 10 Å steps utilizing ToF-SIMS to study the amount 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 exchange coupled with hydrolytic sorption. According to ToF-SIMS and XPS results, the total sorbed amount of Ba2+was larger than that of Cs+. Quantitative determination of the primary cations within the analyzed clay before and after sorption indicated that for Ba2+sorption, Ca2+, Mg2+and for Cs+sorption Ca2+, K+were the major exchanging ions. The XRD spectra of Ba-sorbed clay contained new peaks that were identified as BaCO3.