A bio-inspired algicide might prevent cyanobacterial blooms in Taihu lake

Professor Rao Yijian’s team from Jiangnan University has developed an efficient algae suppression material through biomimetic design. Inspired by the excellent algicidal activity of cercosporin (CP), a novel metal-free algaecide SiO₂@EDU@CP (EDU, N-ethyl-N′-(3-dimethylaminopropyl)urea) with flocculation and photoremoval functions, was successfully designed and prepared in one-step to simultaneously introduce CP and EDU on SiO₂ nanoparticles. It could rapidly form algae flocs in 20 min with 97.1% flocculation rate, and remove Microcystis aeruginosa within 12 h with 91.0% algicidal rate under 23 W compact fluorescent light irradiation without any leaked CP detected. Additionally, odorant β-cyclocitral and toxin microcystin-LR were both photodegraded after treatment of SiO₂@EDU@CP. Mechanistic studies showed that the introduction of EDU significantly reversed the zeta potential of SiO₂-COOH to achieve the flocculation through neutral charge, and the photophysical characterization of SiO₂@EDU@CP revealed the improved charge separation ability to generate reactive oxygen species. More importantly, the utility of SiO₂@EDU@CP was well demonstrated by its effectiveness for algae from Taihu Lake under natural sunlight and inability to regrow after treatment.