Hydroxyl Radical Streaming from Molecular Oxygen Activation by Β-Fec2o4·2h2o for Efficiently Degrading Microcystin-LR

In this study, beta-FeC2O4.2H2O was employed to activate molecular oxygen for the generation of abundant hy-droxyl radicals (center dot OH) for efficient degradation of toxic Microcystin-LR (MC-LR) at ambient conditions. Specif-ically, dioxygen is selectively reduced to H2O2 through a two-electron transfer pathway on the (0 2 2) facet of beta-FeC2O4.2H2O crystals, and then H2O2 reacts with Fe(II) to form center dot OH. The electron utilization efficiency of beta-FeC2O4.2H2O toward center dot OH is high up to 87.7%, ensuring the formation of a sustainable center dot OH stream. In addition, the Fe3+ generated from beta-FeC2O4.2H2O oxygenation coordinates with oxalate to form soluble [Fe3+- (C2O42-)2]- complex, avoiding the formation of passivated Fe(III) oxide/hydroxide shell on beta-FeC2O4.2H2O and enabling the long durability of beta-FeC2O4.2H2O. When MC-LR is oxidized, the center dot OH primarily attacks the conju-gated dienes (the essential group for the hepatotoxicity) in the Adda side chain of MC-LR. The toxicity assessment by PP2A test shows that the oxidation products are not hepatotoxins. As beta-FeC2O4.2H2O governing water treatment is easily manipulated, cost-effective, highly effectual, environmentally benign as well, it is promising to eliminate MC-LR contamination in natural waters and can be applied in large scale.