Degradation and mechanism of microcystin-LR by PbCrO4 nanorods driven by visible light

This work focuses on the photocatalytic removal of recalcitrant organic pollutants in water treatment . Based on facile precipitation reaction, we fabricated a photocatalyst (PbCrO 4 ) in single crystals that present evident response to visible light and employed the catalyst in the photocatalytic decomposition of microcystin-LR (MC-LR). In the degradation test using the nanorods with prepared PbCrO 4 photocatalyst, a 100% removal efficiency (27 min reaction) and a kinetics constant of 0.1356 min −1 were achieved. Such a high performance of PbCrO 4 in photocatalytic conversion of MC-LR was ascribed to its high carrier separation efficiency, positive valence band (VB) position, and good delocalization of VB and conduction band (CB). The test of electron spin-resonance resonance (ESR) demonstrated that excessive free OH radicals were produced during the PbCrO 4 photocatalysis of MC-LR. The density functional theory (DFT) and LC/MS/MS technology were employed to ascertain the intermediates during the MC-LR photocatalytic degradation . The major intermediates were resulted from the attack of hydroxyl radicals to the ADDA side chains of MC-LR structure. This study provides a proof-of-concept strategy to develop effective photocatalysts to efficiently produce OH radicals for the visible-light induced photocatalytic degradation of MC-LR in water.