| Various bimetallic reductants of Cu/Fe, Ag/Fe, Pd/Fe and Ni/Fe were prepared by plating Cu, Ag, Pd and Ni on the surface of Fe０. Reductive dechlorination of toxic pollutants of CCl4 in water with Fe０ and amended Fe０ by batch experiments was investigated. Results show that CCl4 in water can be rapidly dechlorinated by above five catalytic reductants, and the presence of Cu, Ag, Pd can enhance the dechlorination rate dramatically. The reaction of CCl4 with various reductants was followed the pseudo first order kinetics, and the dechlorination rate constant of CCl4 in water by Fe０, Cu/Fe, Ag/Fe, Pd/Fe and Ni/Fe was 0.039 3, 0.092 5, 0.158, 0.049 6 and 0.053 3 min-1 respectively. The byproducts and pathway of dechlorination of CCl4 by Fe０ and amended Fe０ was identified by GC/MS. Results indicate that the products and dechlorination rate of CCl4 by various bimetallic reductants are varied. The main products are chloroform and dichloromethane in Cu/Fe and Ag/Fe system, and that is methane in Pd/Fe system. Hydrogenolysis is the dominant reaction pathway of CCl4 by Fe０ and amended Fe０. |
