Comparative Study on Sorption Additivity of ...

This study focused on sorption of individual and coexisting Cs and Se on bentonite and quartz sand mixtures by batch techniques. Batch kinetic tests have been conducted with carrier free by using individual and coexisting radiotracers ,137Cs and 75Se. The distribution coefficients (Kd) of Cs on bentonite showed that there is no interference on sorption additivity between individual and coexisting value (366±3 and 371±10 mL/g in synthetic groundwater, 43±1 and 60±2mL/g in synthetic seawater). Moreover, individual and coexisting Kd (22±2 and 20±4 mL/g in synthetic groundwater, 10±1 and 14±1 in synthetic seawater) of Se are in similar case with Cs. The experimental results also present in sorption of 137Cs and 75Se on bentonite/quartz sand mixtures (1:1). It is easily found that sorption mechanisms of Cs and Se on bentonite and quartz sand mixtures are independent and different by using radiotracer technique. According to different sorption mechaisms of Cs and Se, the sorption additivity by batch sorption experiments would be quite helpful while assessing buffer materials mixed by bentonite and quartz sand.