Photocatalytic degradation of microcystin-LR in aqueous solutions

Abstract

In this work, the photocatalytic degradation of aqueous microcystin-LR was studied using TiO2 and ZnO as photocatalysts. The process was optimised and characterised at the bench scale (200mL); both semiconductors exhibited a high degradation capacity at reaction times of 1min (degradation greater than 95%). The transient species that were observed indicate that the degradation occurs via the multiple hydroxylation and elimination of the labile peptide residues of the molecule. When photocatalysis was applied in a continuous treatment system (20–50L), the photocatalytic process exhibited a high degradation efficiency, which resulted in residual microcystin-LR concentrations that were less than 1μgL−1 (C0=5μgL−1).