Effects of Oxides in Soil (Sediment) on the Mobility of Phosphorous and Heavy Metals

Concentration, species and mobility of phosphorus and heavy metal in water and soil (sediment) are largely controlled by the surface sorption and desorption processes on iron,manganese and aluminum (hydro) oxides and closely related to people's health. In this paper,a description was given of the environmental effects of phosphorus (P) and heavy metal,and (hydro) oxides of iron,manganese and aluminum were taken as examples,aiming to make an overview of types of oxides in soil(sediment),possible adsorption mechanisms of phosphorus and heavy metal onto oxides(inner-sphere complexation, outersphere complexation and retention in the diffuse swarm)and adsorption models (empirical and semi-empirical isothermal equations,surface complexation model). Then, the main factors affecting the regulation of mobility of P and heavy metal by oxides were summarized and likely competitive and cooperative adsorption behaviors among different oxides were also presented. Obviously, it has been shown that the employment of new in-situ techniques is essential for examining the characteristics of adsorption and desorption occurring at the oxide/water interface at atomic and molecular level,thus being able to better understand the complex reaction processes in multi-interface systems including different oxides or oxide species.