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

[Display omitted] •Novel magnetic Mn-Fe oxycarbide (mMFC)/peroxymonosulfate (PMS) oxidation system.•SO4−, OH, 1O2 and O2− formed simultaneously in the new mMFC/PMS system.•SO4− and OH-based radical process contributed to butyl paraben (BPB) oxidation. 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 (CO groups) and metal (Mn/Fe oxides) species within mMFC as dual active sites activated/catalyzed PMS synergistically to generate SO4−, OH, 1O2 and O2−, then 1O2 and/or O2− served as a secondary driving force to form SO4− and OH 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.