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Adsorption characteristics of cesium on the clay minerals: Structural change under wetting and drying condition

Park, Sang-Min, Lee, Jeshin, Jeon, Eun-Ki, Kang, Seunghee, Alam, Md. Samrat, Tsang, Daniel C.W., Alessi, Daniel S., Baek, Kitae
Geoderma 2019 v.340 pp. 49-54
adsorption, cation exchange capacity, cesium, desorption, drying, illite, kaolinite, montmorillonite, weathering
The fate and transport of cesium (Cs+) is strongly related to the presence of clay minerals in soils, and their weathering due to natural cycles of wetting and drying. In this study, the adsorption characteristics of Cs+ under repeated wetting and drying conditions were investigated using the 1:1 lattice clay mineral, kaolinite, the non-expanding 2:1 lattice clay mineral, illite, and the expanding 2:1 lattice clay minerals, hydrobiotite and montmorillonite. Unlike the cation exchange capacity of clay minerals (montmorillonite > hydrobiotite > illite > kaolinite), the amount of Cs+ adsorbed followed the order of hydrobiotite > montmorillonite > illite > kaolinite. The expanding 2:1 lattice clay minerals (hydrobiotite and montmorillonite) displayed a fixed d-spacing when Cs+ was adsorbed and dried, after which they had a structure similar to that of illite. The desorption efficiency of Cs+ in illite and montmorillonite also was lowered after drying at 80 °C. Desorption efficiencies of Cs+ in clay minerals were in the order of kaolinite > illite > montmorillonite > hydrobiotite. Therefore, there are differences on desorption efficiencies of Cs according to clay minerals due to each clay mineral structure and characteristics.