Enhanced visible light photocatalytic inactivation of Microcystis aeruginosa using Ag2CO3/WO3 with strong internal electric field: Performance and mechanism

Abstract

Eutrophication-induced algal blooms present serious risks to aquatic ecosystems and human health by crowding out the living space of aquatic plants and animals. In this study, an Ag₂CO₃/WO₃ photocatalyst with exceptional optical properties was synthesized using an in situ stirring method. This photocatalyst exhibited remarkable efficacy in the visible light photocatalytic inactivation of Microcystis aeruginosa, achieving nearly 100% algal removal within 180 min. To elucidate the particular effect on algae cell for visible light photocatalytic inactivation, the physiological changes in algal cells were further investigated. Our findings revealed that Ag₂CO₃/WO₃ severely impairs membrane permeability, disrupts stability, and interferes with the physiological metabolism of algal cells, leading to the continuous release and subsequent degradation of intra- and extracellular organic matter. Additionally, several reactive radicals, ·OH, ·O₂⁻, ¹O₂ and h⁺, are considered the primary contributors to the inactivation of algal cells during visible-light photocatalytic inactivation. And efficient electron-hole separation in Ag₂CO₃/WO₃, induced by the internal electric field, is a prerequisite for reactive oxygen species (ROSs) generation. Based on these findings, a potential mechanism for the visible light photocatalytic inactivation of M. aeruginosa by Ag₂CO₃/WO₃ was proposed. Overall, Ag₂CO₃/WO₃ demonstrated exceptional effectiveness in removing M. aeruginosa and held promise for application in managing harmful cyanobacteria blooms in aquatic ecosystems.