Trichloroethylene degradation by zero valent iron activated persulfate oxidation

The present study describes the use of zero valent iron (Fe-0) as a source for ferrous ion activated persulfate (PS) oxidation of trichloroethylene (TCE). The experimental results indicated that in the absence of TCE there was a lag time for persulfate decomposition when the reaction was activated by Fe-0. An initial pH drop in the Fe-0/PS system to acidic conditions was accompanied by the persulfate decomposition and a decrease in oxidation-reduction potential (ORP) values. Furthermore, in the TCE/Fe-0/PS system, the rapid TCE degradation was accompanied by the rapid persulfate decomposition and chloride ion formation as evidence of TCE mineralization. SEM images of Fe-0 before and after persulfate oxidation exhibited significant corrosions of Fe-0. Acicular aggregate formation in the absence of TCE and coarse aggregate formation in the presence of TCE were observed. Moreover, the XRD spectrum revealed the formation of magnetite over the surface of Fe-0 after contact with persulfate. Thus, Fe-0 activated persulfate oxidation offers a fast and effective way for remediation of TCE contamination.