Inactivation of Microcystis aeruginosa by peroxydisulfate activated with single‐atomic iron catalysis: Efficiency and mechanisms

Harmful algal blooms caused by cyanobacteria in drinking water have posed serious threats to destroy aquatic ecosystems , and the toxins they produce are harmful to human and animal health. Herein, the feasibility of removing Microcystis aeruginosa ( M. aeruginos ) and microcystin-LR ( MC-LR ) by free radicals produced by simple-atomic iron-doped g-C 3 N 4 (Fe-g-C 3 N 4 )-activated peroxydisulfate (PDS) was studied. Pristine g-C 3 N 4 and three kinds of Fe-g-C 3 N 4 with different compositions were successfully synthesized and characterized. When the initial algae density was 2.5 × 10 6 cells·mL −1 , approximately 96.25 % of M. aeruginosa cells were inactivated with 2.0 g·L −1 Fe-g-C 3 N 4 and 4.0 mM PDS under the conditions of pH 7.0, and MC-LR could also be effectively degraded. The activated system can effectively remove M. aeruginosa, and MC-LR was evaluated for its morphological characteristics, cell membrane integrity and microcystin degradation. In addition to the widely recognized reaction species (SO 4 • − and • OH), singlet oxygen ( 1 O 2 ) was another predominant radical for destroying the cell structure and removing MC-LR . The materials can be well recycled, and a possible removal mechanism was proposed. This work shows that the Fe-g-C 3 N 4 -activated PDS system is an environmentally friendly and efficient technology for algae removal and algal toxin reduction.