The dechlorination reaction of an aqueous solution of trichloroethylene (TCE) with α-Fe·Fe3O4 composite particles which included 500-4500 ppm sulfur was carried out using shaking and stationary methods. As a result, the following reaction mechanism was obtained. cis-1,2-dichloroethylene (DCE) was produced as the intermediate product at the first step of the dechlorination of TCE, and cis-1,2-DCE was converted into four types of sulfonated hydrocarbon through the reaction. Such a substitution of Cl in cis-1,2-DCE to S proceeded catalytically at the surface of magnetite including in composite particles and S atoms only acted as the promoter of dechlorination without the formation of hydrogen sulfide. These sulfonated hydrocarbons converted to seven types of hydrocarbon as the main products by the successive reactions.
