Kinetic characteristics of hexavalent chromium apparent adsorption on different soils

16 different kinds of soils which collected from 15 provinces in China were chosen to study the Cr (VI)’s kinetic characteristics of apparent adsorption and its influencing factors using vibration batch equilibrium techniques. The results show that bigger apparent adsorption of Cr (VI) exist in the soils with lower pH value and higher clay content, but soil cation exchange capacity and organic matter content has little effects on apparent adsorption of Cr (VI). The acid-soils have bigger adsorptive capacity for Cr (VI) and their Cr (VI) adsorption kinetic characteristics can be well described by the first-order equation and intra particle diffusion model. the equilibrium adsorptive capacity and the adsorption speed of acid-soils have the negative correlation (p＜0.05) with soil pH value, while have the positive significant correlation (p＜0.01) with the content of clay. On the contrast, the alkali-soils have the small adsorptive capacity of Cr (VI), and it is difficult to imitate its kinetic characteristics by any kinetic models. It can be concluded that soil pH value is the main factor that affects not only chromic acid apparent adsorption in soils, but also the kinetic characteristics of those soils.