In situ remediation of ortho-nitrochlorobenzene in soil by dual oxidants (hydrogen peroxide/persulfate).

The efficacies of catalyzed H2O2, activated persulfate, and catalyzed H2O2-persulfate processes for the degradation of ortho-nitrochlorobenzene (o-NCB) in soil were investigated. The application of catalyzed H2O2-persulfate process was promising, and after a careful adjustment of oxidants and activator doses, it demonstrated a considerable improvement in o-NCB degradation compared with activated persulfate process and catalyzed H2O2 process. The degradation of o-NCB in catalyzed H2O2-persulfate process was obviously influenced by the concentration of persulfate and H2O2, the molar ratio between persulfate and H2O2, the concentration of o-NCB, and initial pH. Degradation of o-NCB was obviously inhibited by the addition of tert-butyl alcohol, methanol, and phenol, suggesting that nitrobenzene was dominantly oxidized by HO· and SO4 (-)· generated in the catalyzed H2O2-persulfate process. The results from these studies demonstrated that the natural iron species present in soil could effectively facilitate the degradation of organic pollutants in the presence of H2O2 and persulfate.