Oxidative degradation of benzoic acid using Fe0 - and sulfidized Fe0-activated persulfate: A comparative study

Implications of sulfidized Fe-0(nFe/FeS) for the abatement of pollutants of various categories are widely established. In this study, degradation of one of the major organic pollutants, benzoic acid (BA), has been performed using persulfate activated with nFe/FeS. Complete degradation of BA and its transformed product, hydroxybenzoic acid, was observed within 6 min. When the degradation was performed at alkaline pH, the degradation decreased to 8% in the case of Fe-0, but nFe/FeS still showed 100% degradation after 60 min. Iron dissolution and persulfate decomposition in the presence of scavengers showed that both sulfate and hydroxyl radicals were involved in the Fe-0-persulfate system and that the hydroxyl radicals were the major species in the nFe/FeS-persulfate system. The major degradation pathway of benzoic acid was hydroxylation followed by complete mineralization, as supported by the practical removal of total organic carbons (more than 75% within 15 min). The observed results are promising in using perstlfate activated by nFe/FeS for the remediation of various micro-pollutants from a multitude of water sources. (C) 2017 Elsevier B.V. All rights reserved.