Abstract
The desorption behaviors of Cs from Cs bearing smectite by major cations (Na^+, K^+, Mg^<2+>, Ca^<2+> and NH_4^+) were systematically examined. The suspension of the Cs bearing smectite was prepared by reaction of 1g/L smectite with 75 nM Cs^+ solution in 0.02 M NaCl solutions. The desorption behaviors of Cs were examined by adding the major cations of which concentrations ranged from 10^<-3> to 10^<-1>N to the smectite suspensions. All cations except for K^+ lead to the desorption of Cs from smectite when the concentrations of the added cations increased. On the other hand, K^+ plays a role for inhibition of Cs desorption from smectite. The order of the ability for the desorption of Cs from smectite by the major cations was summarized as follow: Ca^<2+> ≒ Mg^<2+> > NH_4^+ > Na^+ > K^+. The selectivity coefficients based on Gaines-Thomas convention were estimated from the observed desorption behaviors.
