Novel magnetic rod-like Mn-Fe oxycarbide toward peroxymonosulfate activation for efficient oxidation of butyl paraben: Radical oxidation versus singlet oxygenation

A new peroxymonosulfate (PMS) oxidation system was constructed using a novel magnetic Mn-Fe oxycarbide (mMFC) as an activator. We found that the non-metal (-C=O groups) and metal (Mn/Fe oxides) species within mMFC as dual active sites activated/catalyzed PMS synergistically to generate SO4 center dot-, (OH)-O-center dot, O-1(2) and O-2(center dot-) then O-1(2) and/or O-2(center dot-) served as a secondary driving force to form SO4 center dot- and (OH)-O-center dot for butyl paraben (BPB) oxidation via a radical reaction process. The stability of mMFC and the effects of initial pH, dosages, solution temperature and environmental conditions on BPB oxidation kinetics were probed with a proposed catalytic mechanism of mMFC toward PMS activation for BPB oxidation. The revealed radical and singlet formation/evolutions and radical-controlled BPB degradation mechanisms in mMFC/PMS system would advance our knowledge of designing novel magnetic Mn-based oxycarbides with elaborate structures/properties toward PMS activation for effective oxidation of emerging contaminants in wastewater.