Sorption of cesium on Tamusu clay in synthetic groundwater with high ionic strength

Abstract

Abstract The sorption behaviour of cesium on Tamusu clay was first investigated by batch experiments under synthetic groundwater and deionized water conditions. The results showed that the sorption could be well described by the pseud-second-order kinetic model or by the Freundlich isotherm model, and the Kd values decreased rapidly when temperature was greater than 328 K. However, the influence of initial cesium concentration, initial pH and Humic acid (HA) on the sorption behaviour in the synthetic groundwater exhibited a significant difference from those in the deionized water. In particular, the Kd value in the synthetic groundwater (5.47 mL/g) was much lower than that in the deionized water (58.97 mL/g). The SEM/EDS, effect of ion strength and pH-independent results in the synthetic groundwater indicated the cesium sorption on Tamusu clay was mainly involved in an ion exchange process. Additionally, the research reported in this work implies that the retardation of cesium on Tamusu clay was significantly lower than that on other clay rock in the world. The results suggest that the sorption behaviour of cesium or other nuclides on Tamusu clay should be evaluated in synthetic or actual groundwater but not in deionized water.