New insight into the mechanism of peroxymonosulfate activation by nanoscaled lead-based spinel for organic matters degradation: A singlet oxygen-dominated oxidation process.

Author(s) Liu, F.; Li, W.; Wu, D.; Tian, T.; Wu, J.F.; Dong, Z.M.; Zhao, G.C.
Journal J Colloid Interface Sci
Date Published 2020 Jul 15

Crystalline iron-based nanoparticles with spinel structure have received great attention for catalyzing peroxymonosulfate (PMS). This study introduces lead ferrite (PbFeO) as a novel, simple, and efficient catalyst to activate PMS for the degradation of organic contaminants in aqueous solution. The results indicated that, under pH 9.0, nearly 100% of 10 μM thionine was removed in 20 min. Operation factors, including pH, oxidant concentrations, catalyst dosage, and coexisting ions, were investigated and found to be influential for the thionine removal. PbFeO showed higher catalytic activity and lower ions leaching than well-crystallized lead oxide (PbO) and ferric oxide (FeO). The results from the characterization of the PbFeO with X-ray diffraction (XRD) before and after reaction suggested that the structure and properties of the catalyst kept stable, and the recovered catalyst exhibited good catalytic performance during the recycling batch experiments. Free radical quenching experiments and electron paramagnetic resonance (EPR) spectra revealed that singlet-oxygen (O) is the dominant active oxygen species rather than sulfate radical for thionine degradation in PbFeO/PMS system. Meanwhile, the possible pathways of O generation were proposed: the redox reaction between Pb(Ⅳ)/Pb(II) and PMS may play an key role in PMS activation. This study provides an interesting insight in PMS activation by the high-efficient non-radical process, and the PbFeO could be as efficient and recyclable heterogeneous catalyst for organic degradation.

DOI 10.1016/j.jcis.2020.03.116
ISSN 1095-7103
Citation J Colloid Interface Sci. 2020;572:318327.