Mechanism and excellent performance of graphite felt as anodes in electrochemical system for Microcystis aeruginosa and microcystin-LR removal with no pH limitation nor chemical addition

Abstract

• We reported a graphite felt (GF) -Pt electro-chemical system for effective algal removal for the first time. • M. aeruginosa cells and MC-LR were removed by 94% and 50%, respectively, after 30 min. • Chemicals are not needed. The GF-Pt system is available at a wide pH range (3–9). • The removal mechanism acts by direct discharging of anodes with superior electro-adsorption. • After 10 cyclic oxidation experiments, the algal cell removal efficiency was 83%. The outbreak of cyanobacterial blooms has posed a huge threat to drinking water safety and the natural water environment. Among the harmful cyanobacterial bloom types, Microcystis aeruginosa is a force to be recognized with. The purpose of this work was to develop an efficient and eco-friendly technology to curb harmful cyanobacteria blooms and purify bodies of water from polluting algal organic matter. A novel and efficient electrochemical system with a graphite felt (GF) anode and Pt cathode was proposed to treat water containing M. aeruginosa , and its performance and mechanism were investigated. Without chemical consumption, the GF-Pt system with a pH widely ranging from three to nine can inactivate approximately 90% of algal cells in a short time. The ideal GF-Pt system for the removal of algal cells and Microcystin-LR operated under a pH of 7 at 75 mA, achieving removal efficiencies of 94 ± 2% and 50%, respectively. The removal mechanism was determined to be the continuous direct discharging of the anodes, with superior electro-adsorption being the key to anodization efficiency enhancement. After only flushing and drying the GF anodes before reuse, the GF-Pt system was able to maintain an algal cell removal efficiency of 83% after 10 cycles.