RADIOCHEMICAL STUDIES OF THE SORPTION BEHAVIOR OF STRONTIUM AND BARIUM

The sorption behavior of strontium and barium on kaolinite, bentonite and chlorite-illite mixed clay was studied by radioanalytical techniqu es using the batch method. Sr-90 (29.1 y) and Ba-133(10.5 y) were used as radiotracers. Characterization of the solid matrices was done by F TIR and XRD spectrometries and specific surface area measurements. Syn thetic groundwater was used as the aqueous phase. The variation of the distribution ratio Rd, as a function of metal ion loading was examine d. The sorption isotherms were fitted to various isotherm models. ?he sorption energies were calculated to be in the range of 8-10 kJ/mol su ggesting an ion exchange type of sorption mechanism. In detailed exper iments, chlorite-illite mixed clay was first presaturated with K+, Sr2 +, Ca2+ and Al3+ ions, respectively, prior to sorption studies with Ba 2+ ions. The results of Ca2+ pretreated chlorite-illite were very simi lar to those of natural chlorite-illite, suggesting that the Ba2+ ion exchanges primarily with the Ca2+ ion on the clay minerals.