Highly efficient degradation of emerging contaminants by magnetic CuO@FexOy derived from natural mackinawite (FeS) in the presence of peroxymonosulfate

In this study, natural mackinawite (FeS), a chalcophilic mineral, was utilized to prepare iron/copper bimetallic oxides (CuO@FexOy) by displacement plating and calcination process. Various characterization methods prove that Cu-0 is successfully coated on the surface of FeS, which were further oxidized to CuO, Fe3O4 and/or Fe2O3 during calcination process, respectively. CuO@FexOy performed highly efficient capacity to activate PMS for the degradation of various emerging pollutants including sulfamethoxazole (SMX), carbamazepine (CBZ), bisphenol A (BPA), 2,4-dichlorophenol (2,4-DCP) and diclofenac (DCF) in aqueous solution. Complete removal of the above pollutants was observed after 8 min of CuO@FexOy/PMS treatment. Taking SMX as an example, the key parameters including CuO@FexOy dosage, PMS dosage and initial pH were optimized. The results show that the catalytic system can be worked in a wide pH range (3.0-9.0). The quenching experiments and electron spin resonance (ESR) test demonstrated that the main reactive oxygen species in CuO@FexOy/PMS system were hydroxyl radicals ((OH)-O-center dot) and sulfate radicals (SO4 center dot-), and SO4 center dot- was the primary reactive species. Besides, the influence of coexisting anions (i.e., Cl-, NO3-, HCO3- and H2PO4-) for the degradation of SMX was explored. CuO@FexOy/PMS system can maintain good catalytic activity and reusability in different water bodies and long-term running. This work provided a green strategy to fabricate the efficient catalyst in PMS-based advanced oxidation processes. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In this study, iron/copper bimetallic oxides (CuO@FexOy) were prepared using natural mackinawite (FeS) as a precursor. The CuO@FexOy catalyst exhibited highly efficient capacity to activate peroxydisulfate (PMS) for the degradation of various emerging pollutants. The main reactive oxygen species in the CuO@FexOy/PMS system were identified as hydroxyl radicals and sulfate radicals, with sulfate radicals being the primary reactive species. The catalytic system showed good activity and reusability in different water bodies and long-term running.