Sorption/desorption of Strontium and Cesium Cations on Clay colloids

• Main Authors: Chia-hui Hou, 侯佳蕙
• Other Authors: Meei-Ling Chang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/kb8y8q

碩士 === 萬能科技大學 === 工程科技研究所 === 96 === This study investigates the surface properties of clay particles and colloids of kaolinite, montmorillonite and ri-hsing bentonite. Moreover, the sorption/desorption of Cs+ and Sr2+ on the above three kinds of colloid in artificial buffered aqueous solutions were conducted to understand the fate of radioactive cations in the subsurface environment. The results show that the variation extents of specific surface area and cation exchange capacity depend on the kinds of clay particles and colloids. The sorption sites of montmorillonite colloid can be divided into two categories: sites of high energy that are effective sites for low cation concentration and sites of low energy that are only effective under high cation concentration. The fractions of the two kinds of sites vary with different pH conditions. When log [Cs+] or log [Sr2+] ranges among -3.5 to -1.5 mmol/L, the values of partition coefficient remain constant, which contributes to the bases of prediction for the Cs+ and Sr2+ sorption in subsurface environment. The sorbed Cs+ and Sr2+ could not completely desorb from colloids. X-ray defraction spectrums show that the sizes of clay lattice changed after sorption, which is worthy to investigate. The separation with centrifuge in this study was not satisfactorily to evaluate the rapid sorption rates.