SORPTION CHARACTERISTICS OF CESIUM ONTO RESERVOIR SEDIMENT

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 The aim of this study was to evaluate the sorption characteristics of cesium onto freshwater reservoir sediment. For this, batch sorption experiments using sediment collected from a fresh water reservoir were conducted for 27 combinations of water temperature (5, 20 and 35 °C), pH (5, 7 and 9) and EC (130, 160 and 190 μS/cm). In addition, the distribution of adsorbed Cs was examined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the equilibrium sorption data of cesium onto reservoir sediment could be fairly-well described by both Langmuir and Freundlich isotherm models. The estimated isotherm parameters indicated that the impacts of water temperature, pH and EC on the sorption capacity of cesium were less obvious within the investigated ranges of these three variables. EDS mapping and elemental analysis of sediment after cesium sorption, together with the analysis by XRD, revealed that sorption of cesium on the reservoir sediment occurs mainly on its surface and the distribution of the adsorbed Cs on sediment was not uniform.