Study on the removal and degradation mechanism of microcystin-LR by the UV/Fenton system

Microcystin-LR (MC-LR) is highly hepatotoxic and potentially carcinogenic to humans. Therefore, removing MC-LR from water bodies is of paramount importance. This study aimed to investigate the removal efficacy of the UV/Fenton system on MC-LR from copper-green microcystin and to explore its degradation mechanism in simulated real algaecontaining wastewater. The results showed that at an initial concentration of 5 & mu;g & BULL;L-1, a combination of 300 & mu;mol & BULL;L-1 H2O2, 125 & mu;mol & BULL;L-1 FeSO4, and 5 min of UV irradiation under average radiation intensity of 48 & mu;W & BULL;cm-2 resulted in a removal efficiency of 90.65 % for MC-LR. The reduction of extracellular soluble microbial metabolites of Microcystis aeruginosa confirmed the UV/Fenton method's degradation efficiency for MC-LR, while the observation of the functional group C\\H and O\\C_O in the treatment group indicated effective binding sites in the coagulation process. However, the presence of humic substances in algal organic matter (AOM) and some proteins and polysaccharides in the algal cell suspension competed with MC-LR for HO & BULL;, resulting in a decreased removal effect (78.36 %) in simulated actual algae-containing wastewater. These quantitative results provide an experimental basis and theoretical foundation for controlling cyanobacterial water blooms and ensuring drinking water quality safety.

Automated summary

The UV/Fenton system effectively removed MC-LR from water bodies, achieving a removal efficiency of 90.65% under specific conditions. However, the presence of humic substances and certain proteins and polysaccharides in the algal organic matter hindered the removal effect in simulated algae-containing wastewater.