The objective of this study is to investigate the effect of anions on the reactivity of aquocobalamin (III) (B12a) as an electron mediator in the reductive dechlorination of tetrachloroethene (PCE) by nano-Mackinawite (nFeS). B12a forms new complexation species with anions (chloride (Cl-), nitrate (NO3-), phosphate (PO42-), sulfate (SO42-), and sulfide (S2-)) at its axial ligand through the substitution of H2O molecule at pH 8.2. Formation of B12a-S2- decreased the redox potential of B12a from 130 mV to 95 mV in solution. No significant redox potential changes were observed in B12a solution with other anions. Complexation of B12a with S2- leads to reduction of cobalt (III) (550 nm) to cobalt (II) (440 nm) in B12a structure.  Approximately 30% of PCE was degraded by nFeS with B12a-S2- suspension, while no significant of PCE degradation by nFeS with B12a suspension in 72 hrs at pH 8.2. The experimental findings can provide basic knowledge on natural biogeochemical reaction mechanisms for the enhanced reductive dechlorination of chlorinated organics in natural reducing environments.

Effect of aquocobalamin (III)-anion complexes on the reductive dechlorination of tetrachloroethene by nano-mackinawite

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.