Study on phytoremediation with H2O2 pretreatment in heavy metal contaminated soils
重金属污染土壤H2O2预处理的植物修复技术研究

Effect of hydrogen peroxide on the solubilization and rhizospheric dynamics of heavy metals in contaminated soils was studied. The results showed that water soluble Cu and Zn increased significantly after being treated with H_2O_2, which indicatd that H_2O_2 is a safe and efficient reagent to be used in enhancing the availability of heavy metals in soil. Addition of Fe~2+ decreased the water soluble Cu and Zn. The more was Fe~~2+ added, the less was the water soluble Cu and Zn. Planting ryegrass in the contaminated soil pretreated with hydrogen peroxide led to further increase of water soluble Cu and Zn present. And it was more effective of hydrogen peroxide in releasing Cu into soil solution than Zn. The fractionation of heavy metals was similarly distributed among soils. But hydrogen peroxide pretreatment distinctively increased the copper in the soluble plus exchangeable fraction (SE-Cu) in the planted soil, which indicated that binding strength of heavy metals in soil was weakened after the soil was treated with hydrogen peroxide, and was liable to be mobilized by the influence of the rhizosphere of ryegrass. Besides, the increase of copper and zinc levels in the weekly and specifically adsorbed fraction (WSA-Cu, WSA-Zn) and decrease of residual Cu and Zn levels were also observed in planted soil after hydrogen peroxide treatment. In conclusion, hydrogen peroxide pretreatment might be an efficient way for enhancing the bioavailability of heavy metals in soil and promoting the absorption of heavy metals by plants.