Magnetic recyclable visible light-driven BiWO/FeO/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 FeO/BiWO/Reduced graphene oxide composites (BiWO/FeO/RGO) were employed to degrade MC-LR. The removal efficiency and kinetic constant of the optimized BiWO/FeO/RGO (BiWO/FeO-40%/RGO) was 1.8 and 2.3 times stronger than the pure BiWO. The improved activity of BiWO/FeO-40%/RGO was corresponded to the expanded visible light adsorption ability and reduction of photogenerated carrier recombination efficiency through the integration of BiWO and FeO-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, CO, NO, HPO) reduced MC-LR removal efficiency of BiWO/FeO-40%/RGO. The BiWO/FeO-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 ∙O played a significant role in MC-LR degradation. The LC-MS/MS result revealed the intermediates and possible degradation pathways.