Construction of g-C3N4 with N2C-type defects/MoO3 Z-scheme photocatalyst: Effective mineralization and toxicity reduction of microcystin-LR by multiple free radical degradation pathways

Abstract

Algal blooms have resulted in the buildup of microcystin (MC-LR) in water bodies, posing a severe hazard to the safety of the aquatic ecosystem and human health. This study produced a g-C3N4 with N2C-type defects/MoO3 Z-scheme photocatalyst (D-CN/MoO3) for MC-LR degradation in visible light. D-CN/MoO3 could photodegrade 100 % MC-LR within 25 min, which was substantially more significant than pure g-C3N4 (12.5%). Meanwhile, the kinetic constant was 32.5 times higher than pure g-C3N4, attributed to the defect engineering and Z-scheme heterojunction cooperative interaction. Based on the LC-MS results, the vital degradation mechanism is the selective assault of 1O2 on the Adda side chain of MC-LR and the following decarboxylation reaction of h+, which leads to effective mineralization and reduced toxicity of MC-LR. Moreover, the excellent stability and adaptability of D-CN/MoO3 are verified and have a significant potential for application in the decontamination of MC-LR in eutrophic water.