Kinetics of adsorption and desorption of imazethapyr on black soil and Planosol soil

The kinetics rule of adsorption and desorption of imazethapyr on Black soil and Planosol soil was studied. According to 10∶1 ratio of water and soil, adsorption-desorption kinetics of imazethapyr on Black soil and Planosol soil was studied by the batch equilibrium method at 25±2°C. The results showed that dual constant equation can describe well the adsorption and desorption kinetics of imazethapyr. Comparing with Planosol soil, the capacity of adsorption and desorption on Black soil was higher. Adsorption rate of Imazethapyr on two kinds of soil was higher than desorption rate. Adsorption rate and desorption rate of imazethapyr with higher initial concentration were higher than those with lower initial concentration. The adsorption rate and desorption rate of imazethapyr on Black soil were higher than those on Planosol soil. The desorption capacity of imazethapyr on Black soil and Planosol soil increased with the adsorption capacity before desorption, which showed significantly square power functional relationship between them. There was the same rule in kinetics of adsorption and desorption of imazethapyr on Black soil and Planosol soil. In the case of the same adsorption or desorption time, the adsorption or desorption capacity and adsorption or desorption rate of imazethapyr on Black soil were higher than those on Planosol soil. The desorption capacity of imazethapyr on Planosol soil was higher than that on Black soil, when the adsorption capacity before desorption was same. It was due to the organic matter content, pH vale and initial capacity of adsorption or desorption in the soil.