Dechlorination of hexachlorobenzene over Mg-Fe composite oxides

Mg-Fe composite oxides with different Mg/Fe atomic ratios were synthesized by co-precipitation and characterized by X-ray diffraction (XRD). Their dechlorination activities were evaluated using hexachlorobenzene (HCB) as a model compound. The experiments were carried out at 300 degrees C for 0.5 h. The results indicate that the Mg-Fe composite oxide (Mg/Fe atomic ratio was 8) exhibits the best dechlorination activity among the oxides examined. This may be related to the formation of MgFe2O4 phase with small crystal size. The products after reaction were analyzed by GCMS, XRD, and a chloride selective electrode. It was found that hydrodechlorination took place in the destruction of HCB. The discrepancy in the material balance between starting material and dechlorinated products indicates that, in addition to hydrodechlorination, other degradation routes may be present.