环境中氧化锰对Cr(Ⅲ)氧化机理的研究

MECHANISM OF Cr(Ⅲ) OXIDATION BY Mn OXIDES

研究了几种人工合成的氧化锰和新鲜田间土样对Cr(Ⅲ)的氧化作用.结果表明,自然土壤环境中,氧化锰是Cr(Ⅲ)氧化的主要电子接受体,氧化能力δ-MnO_2>α-MnO_2>γ-MnOOH.土壤对Cr(Ⅲ)氧化能力与易还原性氧化锰含量显著相关.土壤风干后,氧化Cr(Ⅲ)的能力明显降低.并提出了Cr(Ⅲ)在MnO_2表面氧化的机理.

Cr(Ⅲ) oxidation by several Mn oxides and soils was studied. The results showed that Mn oxides were the main electron acceptor in the process of Cr(Ⅲ) oxidation in natural soil environment. The ability of Cr (M) oxidation by several synthesised Mn oxides followed the sequence. δ-MnO2>α-MnO2> γ-MnOOH. The amount of Mn oxide which can be reduced by hydroquinone was positively correlated with the amount of Cr(Ⅲ) oxidized in 15 fresh soil samples. It was discovered that fresh moist soils would oxidize more quantity of Cr(Ⅲ) than dry soils. A mechanism of Cr(Ⅲ) oxidation at MnO2 surface was proposed.