Magnetic recyclable visible light-driven Bi 2 WO 6 /Fe 3 O 4 /RGO for photocatalytic degradation of Microcystin-LR: Mechanism, pathway, and influencing factors.

Photocatalysis was an attractive strategy that had potential to tackle the Microcystin-LR (MC-LR) contamination of aquatic ecosystems. Herein, magnetic photocatalyst Fe3 O4 /Bi2 WO6 /Reduced graphene oxide composites (Bi2 WO6 /Fe3 O4 /RGO) were employed to degrade MC-LR. The removal efficiency and kinetic constant of the optimized Bi2 WO6 /Fe3 O4 /RGO (Bi2 WO6 /Fe3 O4 -40%/RGO) was 1.8 and 2.3 times stronger than the pure Bi2 WO6 . The improved activity of Bi2 WO6 /Fe3 O4 -40%/RGO was corresponded to the expanded visible light adsorption ability and reduction of photogenerated carrier recombination efficiency through the integration of Bi2 WO6 and Fe3 O4 -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 - , H2 PO4 - ) reduced MC-LR removal efficiency of Bi2 WO6 /Fe3 O4 -40%/RGO. The Bi2 WO6 /Fe3 O4 -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.