SORPTION CHARACTERISTICS OF CESIUM ON SANDY SOILS AND THEIR COMPONENTS

Batch type sorption and desorption experiments of cesium at 2.4 X 10(-9) M on sandy soils and the reference minerals of the soil components have been carried out. The sorption behavior of cesium is different from that expected on the assumption that all of cesium is reversibly sorbed on the sandy soils. This results mainly from irreversible sorption of cesium on sericite, from which cesium is not desorbed with a 1 M KCl solution. Observations of fractions of cesium not desorbed from the sandy soils with a 1 M KCl solution at different cesium concentrations suggest that 2 to 3 percent of the sorption sites of the sandy soils are irreversible sites. However, some of the cesium at 2.4 X 10(-9) M is not irreversibly sorbed on the sandy soils. This may be a result of the kinetic effect of cesium sorption on the sandy soils, in which the rate constant of irreversible sorption decreases exponentially with time.