Vitamin B12-mediated hydrodechlorination of dichloromethane by bimetallic Cu/Al particles

Vitamin B-12-mediated hydrodechlorination was carried out to effectively transform dichloromethane (DCM) to methane with bimetallic copper/aluminum (Cu/Al) particles. DCM is known as a recalcitrant chlorinated organic contaminant unable to be degraded by many reductive technologies including zero-valent iron (ZVI), bimetallic palladium/iron (Pd/Fe) nanoparticles, and many other zero-valent metals. Cu/Al bimetal is a low-cost and high effective reactive material. Unlike expensive borohydride-synthesized copper nanoparticles, Cu/Al bimetal particles prepared by reduction of cupric ion using zero-valent aluminum offers high surface areas (>100 m(2) g(-1)) and strong reducing conditions at a low cost. In this study, though the degradation of DCM by Cu/Al alone was relatively slow, an order of magnitude increase in reaction rates was observed when vitamin B-12 was added into the Cu/Al reaction system. Approximately 98% of the DCM was degraded rapidly within 2 h by Cu/Al and vitamin B-12. Reaction mechanisms of DCM degradation in this B-12-Cu/Al system were proposed. UV/Visible spectra showed that vitamin B-12 (CORD was reduced to vitamin Bur (Co(II)) without further reduction to vitamin B-12s (Co(I)) in the presence of Cu/Al. A synergistic effect of copper and vitamin B-12 facilitating the carbon-chlorine (C-Cl) bond scission on the copper surface enhanced the reductive dechlorination of DCM. (C) 2015 Elsevier B.V. All rights reserved.