Reduction of halogenated hydrocarbons in aqueous media: I. Involvement of sulfur in iron catalysis.

Experiments were carried out to investigate the reduction of tri- and tetra-chloroethene with iron in aqueous solutions. Results indicate (i) dependence of the dehalogenation capacity of the iron on its sulfur content and (ii) that ethyne was the primary dehalogenated hydrocarbon for both compounds. A reaction mechanism based on in situ formation of ferrous sulfide as the catalyst and its reaction with the halocompounds in the presence of hydrogen has been postulated.