Effect of different organo-mineral complexes on adsorption characteristic of phosphorus on sandy soil
沙土不同有机矿质复合体对磷的吸附特征影响

Effect of different organo-mineral complexes on adsorption characteristic of phosphorus on sandy soil was investigated by batch experiments of equilibrium adsorption. Results indicated that the sorption capacity on the sandy soil reduced dramatically after humus was removed. Normalized sorption capacity and partition coefficient only accounted for 38.41% and 7.42% of original sample, respectively, and organo-mineral complex was a main factor in phosphorus sorption on sandy soil. Normalized carbon sorption capacity of Ca-bound complex was 388.35 mg·kg-1, which was about 1.51 times the original sample. The sorption mechanism of phosphorus on Ca-bound complex was micro-hole function filling. In addition, Fe/Al-bound complex played an important role in phosphorus adsorption. Normalized carbon sorption capacity of Fe/Al-bound complex was 500.23 mg·kg-1, which was about 1.93 times the original sample. The sorption mechanism of phosphorus on Fe/Al-bound complex was Fe/Al oxide or hydration oxide coordination sorption apart from micro-hole function filling. The adsorption capacity was determined by not only organic matter content, but also existent state of organic matter which was an important factor in sorption characteristic of phosphorus on sandy soil. Treating original sample as a basic standard, adsorption capacity of phosphorus on Ca bound complex and Fe/Al bound complex were estimated in accordance with 1.51 and 1.93 times.