Equilibrium and kinetic sorption behaviors of cesium and strontium in soils

The equilibrium and kinetic sorption of cesium and strontium was studied in some varieties of important-crude soil in Taiwan using the batch method. Cesium and strontium sorption data at 20 C were fitted to the Freundlich and Langmuir sorption isotherms. Nonlinear isotherms were found, and the Freundlich isotherm provided a better fit of the ion equilibrium sorption than the Langmuir isotherm did for both soils. The linear sorption isotherm was feasible for Sr2+ sorption on both soils with an initial concentration <10 4N; however, Cs+ was not. Both nuclides sorptions on chosen soils indicated two mechanisms at least, and the sorption process is diffusion-controlled. The sorption rate coefficients of Cs+ and Sr2+ of chosen soils at 25 C were determined in this study. The free energy of Cs+ and Sr2+ sorption at dilute solution on given soils was calculated from Freundlich isotherm constant.