译 名：
THE CHARACTERISTICS OF Cr(Ⅲ)OXIDATION BY SEVERAL Fe-Mn NODULES IN SOILS Ⅱ. EFFECT OF pH,IONIC STRENGTH AND TEMPERATURE
作 者：
Liu Gui-qiu Tan Wen-feng Feng Xiong-han Liu Fan(Key Lab of Subtropical Agricultural Resource and Environment,Ministry of Agriculture. Dept.of Resource and Environment,Huazhong Agricultural University,Wuhan 430070,China)
关键词：
Manganese oxide,Cr(Ⅲ),Redox,Iron-manganese nodule,Soil
摘 要：
Manganese oxide minerals are important scavenger of heavy metals and oxidants of changeable valent elements in soils and aquatic environment.Previous studies on redox reaction between Mn oxides and Cr(III) were mainly achieved by using synthetic Mn oxides,and little literature is available on redox reaction of Cr(III) and Mn oxides from soils.Fe-Mn nodules were major depositing forms of Mn in soils.Influences of pH,ion strength and temperature on the oxidation of Cr(Ⅲ) by Fe-Mn nodules from soils were investigated by means of chemical analysis and equilibrium techniques.The results showed that the amounts of Cr(Ⅲ) oxidized by Fe-Mn nodules increased as pH decreasing,ion strength and temperature increasing.It was related to charge properties and electric potential of Mn oxide surface,and coexistence of Fe oxides besides consumption of H + during redox reaction.The ranging amounts of Cr(Ⅲ) oxidized by N2-1 and N4-1 contained birnessite and lithiophorite were larger than that by N5-1 contained todorokite and lithiophorite under above conditions.These diversities were related to crystallinity,crystal structure,and Mn(Ⅳ) content of Mn oxides in Fe-Mn nodules.These data are useful for predicting chrome transport in the environment,and understanding functions of Mn oxide minerals in soil and sediment particles.
