Sorption characteristics of Cs+ and Sr++on montmorillonite and kaolinite type clays and soil fractions from various regions of Turkey were studied using the batch method. 137Cs and 90Sr were used as tracers. Concentrations of Cs+ and Sr++ ions ranged from 10-8to 10-2 mol/1; natural groundwater was used and the grain size of the solid particles was < 20 yμm. Equilibrium was reached in 4 - 7 days for Cs+and 7 - 11 days for Sr++. The distribution coefficient, RD, increased with decreasing grain size, suggesting mainly a surface phenomenon. The sorption isotherms were non-linear suggesting at least two different sorption processes. The sorption was found to be predominantly reversible. Cs+ was sorbed much stronger than Sr++in all samples. © 1988, Walter de Gruyter. All rights reserved

Granite / Sorption / Batch method / Column method / Retardation factor / Distribution ratios SummaryThe sorption behaviour of Ba 2+ and Sr 2 " 1 " cations on granite have been studied under flowing and static conditions in column and batch experiments. 133 Ba, '"Sr and 3 H were used as radio tracers. The retardation factors, R fi and distribution ratios, R d , of barium and strontium in column experiments were found to be smaller than those from batch experiments. In both techniques barium was sorbed more strongly on granite than strontium. Sorption energies were found to be in good agreement with literature values.

The sorpt ion behavior of strontium and barium on kaolinite, bentonite and chlorite-illite mixed clay was studied by radi0mralytical techniques using file batch method. 90Sr (29.1 y) and 133Ba (10.5 y) were used as radiotracers. Characterization of the solid matrices was done by FFIR and XRD spectrometries and specific surface area measurements. Synthetic groundwater was used as the aqueous phase. The variation of the distribution ratio Rd, as a function of metal ion loading was examined. The sorption isotherms were fitted to various isotherm models. The sorption energies were calculated to be in the range of 8-10 k J/tool suggesting an ion exchange type of sorption mechanism. In detailed experiments, chlorile-illite mixed clay was first presaturated with K +, Sr 2+, Ca 2+ and A13+ ions, respectively, prior to sorption studies with Ba 2+ ions. The results of Ca 2+ pretreated chlorite-illite were very similar to those of natural chlorite-iUite, suggesting that the Ba 2 § ion exchanges primarily with the Ca 2 § ion on the clay minerals.The sorption of waste radionuclides on to soil constituents, particularly on clay minerals act as a barrier to their dispersion by the groundwater. Many investigations on radionuclide migration and their sorption behavior have been carried out. 1-1~ The general objective was to understand the effects of different parameters such as composition of groundwater, its pH, structure of solid maWix on the sorption process as well as to establish a basis for the modelling and prediction of radionuclide behavior in the geological environment.In this work the sorption behavior of Sr 2 § and Ba 2* cations were studied. The results would contribute to the establishment of a data base for migration models. Furthermore, since strontium and barium are homologs of important species radium, their results could provide information about the migration behavior of radium.

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