Sorption of barium on kaolinite, montmorillonite and chlorite

The sorption characteristics of the Ba2+ ion on kaolinite, montmorillonite and chlorite type clays were studied using the batch method. Barium-133 was used as a tracer. The Ba2+ ion concentrations ranged from 10-8 to 105 moll-1; synthetic ground water was used and the grain size of all the solid particles was less than 40 micron. About 6, 8 and 12 d of shaking were necessary to reach equilibrium for chlorite, kaolinite and montmorillonite, respectively. The sorption data were described best by Freundlich and Dubinin - Radushkevich type isotherms. Sorption was predominantly reversible for kaolinite and partly reversible for montmorillonite and chlorite. Sorption of Ba2+ is important since the fission product 140Ba is a serious radiocontaminant, e.g from nuclear power plants, and the chemical properties of Ba2+ lie between those of Sr2+ and Ra2+, both very important nuclides in the handling of radioactive waste. 9 refs.