Reductive Dechlorination of Chlorinated Hydrocarbons in Water by Cu/Fe Bimetallic Reductant

The influence of Cu on the dechlorination rate of various chlorinated hydrocarbons including CF, CT, 1,1,2,2-TeCA, 1,1,2,2-TeCA and HCA by Fe⁰ and Cu/Fe was investigated in batch experiments. All organohalides can be dechlorinated rapidly by Fe or Cu/Fe in aqueous system and the contaminants were degraded via sequential reductive dechlorination to form less chlorinated homologues. The removal of CF, CT, 1,1,1-TCA, 1,1,2,2-TeCA and HCA followed pseudo-first-order kinetics both in Fe⁰ system and Cu/Fe system. Cu/Fe reductant could enhance the dechlorination rate of all chlorinated hydrocarbons.The degradation rate constant of a general dechlorination was increased by a factor of 3 in Cu/Fe system than that in Fe⁰ system. The intermediate products of dechlorination and the major pathway were summarized in this study. Hydrogenolysis and reductive elimination was the dominant reaction for various chlorinated hydrocarbons dechlorination by Cu/Fe with respect to the products.