Study on the characteristics of kinetic of cadmium retention on soils

Kinetic characteristics of cadmium retention by different soils were studied using the batch techniques. Cadmium is adsorbed by the soils at different rates. According to the rate, the reaction of retention can be divided into two types: fast and slow. For the fast reaction, the chemical adsorption is the main adsorption, for the slow one, the physical adsorption is the main adsorption. At low temperature (293K), cadmium retention rate and the time accord with the model ln V=A+Bt, at high temperature (313K), V=A+B ln t model is the best one. For the different soils, the optimum model of cadmium retention is the two constants model.