LAUSR

Abstract Epichlorohydrin (ECH) is a volatile organic compound and toxic to human health. Here we investigated clean mediated electrocatalytic dechlorination of ECH in aqueous solutions using electrogenerated [Nickel(I)(hexamethylcyclam)] + ([Ni(I)(hmc)] + ) at glassy carbon cathode. Ni(II)/Ni(I) redox behavior of [Ni(II)(hmc)] 2+ , examined first by cyclic voltammetry in ECH free-aqueous solutions of various anions (Cl − , Br − , ClO 4 − , SO 4 2− , phosphate, NO 3 − ), showed only Cl − could provide most stable and reactive low-valent nickel species with highest versatility toward activation of ECH dechlorination. Cyclic voltammetry experiments over a range of scan rates and ECH concentrations elucidated rate limiting mechanism for Ni(I) catalyzed ECH dechlorination, and estimated catalytic reaction rate constant ( k cat ). ECH concentration-dependent k cat and i cat results revealed ECH dechlorination by Ni(I) followed Michaelis-Menten type inner-sphere electron transfer kinetics at low ECH concentrations ( outer-sphere mechanism at higher concentrations. Interestingly, GC/MS showed complete destruction of ECH and production of three non-chloro products within 3-h bulk electrolysis. A possible mechanism was proposed for the overall Ni(I)(hmc)-catalyzed ECH dechlorination. Fast mediation kinetics, total removal of ECH, non-chloro organics as the only dechlorination products, and highly stable [Ni(I)(hmc)] + mediator indicate electrocatalytic mediation using [Ni(I)(hmc)] + in aqueous NaCl solution may be feasible for dechlorination of other organic chloro compounds.