Heterogeneous Fenton Photodegradation of Microcystin-LR with Visible Light Irradiation

Under condition of visible light irradiation (λ > 450 nm), the degradation mechanism of microcystin-LR is studied using heterogeneous Fenton system, with H2O2 and FeY catalyst, which is prepared by loading Fe2+ to the molecular sieve NaY. The results indicate that the degradation rate of microcystin-LR is up to 90% in the wide pH range using Vis/FeY/H2O2 system. Based on the intermediates detected by LC-MS analysis, the possible pathways and the three vulnerable oxidation sites are put forward: (1) the conjugated double bonds of the Adda chain, (2) the methoxy group of the Adda chain, and (3) unsaturated double bond of the Mdha chain. FeY catalyst exhibits good stability, possessing catalytic activity even after repeated use for 5 times, which indicates its potential application to alga wastewater treatment.