Adsorption Behaviour of Cesium on Marl

Abstract

AbstractAdsorption of Cs on two samples of marl with different calcite, quartz and clay contents and surface areas of ∼10 m2/g was followed using the batch sorption technique. The experiments were carried out in an atmosphere of N2/1% CO2 using a synthetic groundwater of pH 7·3 and an ionic strength of 0·1 m. The initial Cs concentration ranged from 10−8 to 10−4m. Sorption of Cs was non-linear, fast and reversible. At equilibrium Cs concentrations <10−8m, an isotope exchange mechanism appeared to operate, whereas at higher concentrations, sorption involved ion exchange. The distribution coefficients ranged from 23–995 ml/g. They varied markedly with rock/water ratio; this variation could be explained in terms of the non-linear isotherm displayed by Cs. Although the two samples of marl differed in composition, uptake of Cs on both samples was very similar because the content of the principal sorbing component (illite) was the same in both samples.