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

Fu Liu; Wenwen Li; Dechang Wu; Tong Tian; Jian-Feng Wu; Zong-Mu Dong; Guang-Chao Zhao

doi:10.1016/j.jcis.2020.03.116

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

J Colloid Interface Sci. 2020 Jul 15:572:318-327. doi: 10.1016/j.jcis.2020.03.116. Epub 2020 Mar 31.

Authors

Fu Liu¹, Wenwen Li¹, Dechang Wu¹, Tong Tian¹, Jian-Feng Wu¹, Zong-Mu Dong¹, Guang-Chao Zhao²

Affiliations

¹ College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, PR China.
² College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, PR China. Electronic address: gczhao@mail.ahnu.edu.cn.

PMID: 32272310
DOI: 10.1016/j.jcis.2020.03.116

Abstract

Crystalline iron-based nanoparticles with spinel structure have received great attention for catalyzing peroxymonosulfate (PMS). This study introduces lead ferrite (PbFe₂O₄) 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. PbFe₂O₄ showed higher catalytic activity and lower ions leaching than well-crystallized lead oxide (PbO) and ferric oxide (Fe₂O₃). The results from the characterization of the PbFe₂O₄ 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 (¹O₂) is the dominant active oxygen species rather than sulfate radical for thionine degradation in PbFe₂O₄/PMS system. Meanwhile, the possible pathways of ¹O₂ 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 PbFe₂O₄ could be as efficient and recyclable heterogeneous catalyst for organic degradation.

Keywords: Lead ferrite nanocomposites; Organic contaminants degradation; Peroxymonosulfate activation; Singlet-oxygen oxidation.