Ag/Fe催化还原体系处理水体中氯代烃的研究

研究了水体中的三氯甲烷(CF)、四氯化碳(CT)、1,1,1-三氯乙烷(1,1,1-TCA)、1,1,2,2-四氯乙烷(1,1,2,2-TeCA)、六氯乙烷(HCA)、三氯乙烯(TCE)、四氯乙烯(PCE)在Ag/Fe以及Fe⁰还原体系中的还原脱氯反应.结果表明,Ag的加入会明显提高氯代烃的还原脱氯速率,铁表面积浓度为150 m²·L^-1时,如果单独使用Fe⁰,CF、CT、1,1,1-TCA、1,1,2,2-TeCA、

Reductive Dechlorination of Chlorinated Hydrocarbons in Water by Ag/Fe Catalytic Reduction System

Dechlorination of many kinds of chlorinated hydrocarbons including trichloromethane (CF), tetrachloromethane (CT), 1, 1,1-trichloroethane (1, 1, 1-TCA), 1, 1, 2, 2-tetrachloroethane (1, 1, 2, 2-TeCA), hexachloroethane (HCA), trichloroethylene (TCE), perchloroethylene (PCE) in water by Fe and Ag/Fe were investigated. Results show that the existence of Ag on Fe can enhance the dechlorination rate of chlorinated hydrocarbons. When the surface area concentration of iron is 150 m2 x L(-1), the dechlorination rate constant of CF, CT, 1, 1, 1-TCA, 1, 1, 2, 2-TeCA, HCA are 0.084 h(-1), 2.358 h(-1), 0.417 h(-1), 0.215 h(-1), 1.098 h(-1) by single Fe0, in this condition, no dechlorination of TCE and PCE during 10h, while the dechlorination rate constant of CF, CT, 1, 1, 1-TCA, 1, 1, 2, 2-TeCA, HCA, TCE, PCE are up to 1.850 h(-1), 9.504 h(-1), 1.624 h(-1), 1.778 h(-1), 2.842 h(-1), 0.463 h(-1), 1.251 h(-1) by Ag/Fe. The dechlorination rate constant of CF can increase by the factor of 20. The reaction pathways of chlorinated hydrocarbons with Fe and Ag/Fe were mainly including hydrogenolysis, reductive elimination and dehydrochlorination. The hydrogenolysis is the main reaction pathway for CF, TCE and PCE. The dechlorination pathway of 1, 1, 1-TCA are both hydrogenolysis and dehydrochlorination. Reductive beta elimination to form DCE is the dominant reaction pathway of 1, 1, 2, 2-TeCA, and HCA is via reductive beta elimination to form PCE firstly, then via hydrogenolysis to DCE.