The Dissimilatory Fe(Ⅲ) Reduction And Effect On Cr(Ⅵ) Reduction In Paddy

The paddy soil is very important in our agriculture soil. The process of iron oxide and reduce is a chemical and biochemical process which has important significance. In recent years, there has been found a new way to recover soil pollution through the dissimilatory Fe (III) reduction. The dissimilatory Fe (III) reduction is to reduce Fe (III) to Fe (II) by microbe with Fe (III) as electron acceptor to oxidate electron donor , while the microbe can grow up with energy got in this process. So the dissimilatory Fe (III) reduction has important geological and environmental significance because this process can relate with the organic metabolize and volatile element form translation. The dissimilatory Fe (III) reduction in paddy soil also is a microbe metabolize, different electron donor and acceptor can make effect on Fe (III) reduction. The flow of electron direction in this microbe metabolize process may be changed with Cr (VI) as the electron competitive in Fe (III) reduction. So, make deep research with the translated relation in Fe (III) and Cr (VI) system and discuss the mechanism of Fe (III) microbial reduction and Cr (VI) reduction have important theoritic and practical significance. Through the experiment of anaerobic constant temperature incubation, we study the effect of Fe (III) reduction through adding Fe (III),glucose,Cr(VI). And detected the variant of Cr(VI) concentration in soil, discussed competitive relation in Fe (III) and Cr (VI) reduction. Research the way to dispose chrome slag in Fe (III) reduction system through using chrome slag as the form of adding Cr(VI) in soil. The main result we get in experiment is as follow: 1. The adding of iron oxide and carbon resource can promote Fe (III) reduction in the condition of anaerobic incubate in paddy soil and can reduce the Cr(VI) concentration in soil remarkably. 2. Adding Cr (VI) make Fe (III) reduction delay in soil. Adding high Cr (VI) concentration restrain Fe (III) reduction remarkably. Different Cr (VI) concentration have different effect on Fe (III) reduction system, found out the dividing level is 20mmol/L Cr (VI). Beyond this level Fe (III) reduction had been restrained seriously or Fe (III) reduction did not occurred; Below this level the Fe (III) reduction can occur easily but still be restrained with Cr (VI) concentration increasing. 3. Cr (VI) reduction can occur easily or not had relationship with the dissimilatory Fe (III) reduction system in paddy soil. Adding Fe (III) and glucose can promote Fe (III) reduction which offer the condition to Cr (VI) reduction. And Cr (VI) reduction in soil can take part in the dissimilatory Fe (III) reduction system. 4. The mechanism of competitive reduction in Fe (III) and Cr (VI) in the anaerobic paddy soil is:The organic electron donor make the microbia reduction and the Fe (II) that process produced make the chemical reduction of Cr (VI) in soil. 5. Adding the chrome slag can be reduced rapidly in paddy soil with anaerobic incubation and the rate of Cr (VI) reduction promote with adding Fe (III) in the system. Through the building of Fe (III) reduction system can promote the Cr (VI) reduction in chrome slag and built a new system to dispose the chrome slag and recover Cr (VI) polluted soil.