Magnetic recyclable visible light-driven Bi2WO6/Fe3O4/RGO for photocatalytic degradation of Microcystin-LR: Mechanism, pathway, and influencing factors

Mingming Zhan; Yu Hong; Zhi Fang; Daping Qiu

doi:10.1016/j.envres.2024.118885

Magnetic recyclable visible light-driven Bi₂WO₆/Fe₃O₄/RGO for photocatalytic degradation of Microcystin-LR: Mechanism, pathway, and influencing factors

Environ Res. 2024 Apr 16;252(Pt 2):118885. doi: 10.1016/j.envres.2024.118885. Online ahead of print.

Authors

Mingming Zhan¹, Yu Hong², Zhi Fang³, Daping Qiu³

Affiliations

¹ Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China.
² Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; Engineering Research Center for Water Pollution Source Control & Eco-remediation, College of Environmental Science and Engineering, Beijing Forestry University, Beijing, 100083, China. Electronic address: yuhong829908@gmail.com.
³ School of Materials Science and Engineering, Peking University, Beijing, 100871, China.

PMID: 38614200
DOI: 10.1016/j.envres.2024.118885

Abstract

Photocatalysis was an attractive strategy that had potential to tackle the Microcystin-LR (MC-LR) contamination of aquatic ecosystems. Herein, magnetic photocatalyst Fe₃O₄/Bi₂WO₆/Reduced graphene oxide composites (Bi₂WO₆/Fe₃O₄/RGO) were employed to degrade MC-LR. The removal efficiency and kinetic constant of the optimized Bi₂WO₆/Fe₃O₄/RGO (Bi₂WO₆/Fe₃O₄-40%/RGO) was 1.8 and 2.3 times stronger than the pure Bi₂WO₆. The improved activity of Bi₂WO₆/Fe₃O₄-40%/RGO was corresponded to the expanded visible light adsorption ability and reduction of photogenerated carrier recombination efficiency through the integration of Bi₂WO₆ and Fe₃O₄-40%/RGO. The MC-LR removal efficiency exhibited a positive tendency to the initial density of algae cells, fulvic acid, and the concentration of MC-LR decreased. The existed anions (Cl^-, CO₃^-2, NO₃^-, H₂PO₄^-) reduced MC-LR removal efficiency of Bi₂WO₆/Fe₃O₄-40%/RGO. The Bi₂WO₆/Fe₃O₄-40%/RGO could degrade 79.3% of MC-LR at pH = 7 after 180 min reaction process. The trapping experiments and ESR tests confirmed that the h⁺, ∙OH, and ∙O₂^- played a significant role in MC-LR degradation. The LC-MS/MS result revealed the intermediates and possible degradation pathways.

Keywords: Bi(2)WO(6)/Fe(3)O(4)/RGO; Degradation pathways; Intermediates; Magnetic photocatalysts; Microcystin-LR.