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Electrochemical oxidation of Microcystis aeruginosa using a Ti/RuO2 anode: contributions of electrochemically generated chlorines and hydrogen peroxide

Lin, Li, Meng, Xiaoyang, Li, Qingyun, Huang, Zhuo, Wang, Linling, Lin, Ke, Chen, Jin, Crittenden, John
Environmental science and pollution research international 2018 v.25 no.28 pp. 27924-27934
Microcystis aeruginosa, algae, anodes, chlorides, chlorine, drinking water treatment, electric field, electrochemistry, electrolysis, half life, hydrogen peroxide, kinetics, models, oxidants, oxidation, prediction, surface water
Electrochemical oxidation was proposed as a promising technology for algal control in drinking water treatment. To be effective, the electrogenerated oxidants should have long half-lives and could continually inhibit the growth of algae. In this study, we used the electrochemical system equipped with a Ti/RuO₂ anode which focus on generating long half-life chlorines and H₂O₂. We explored the impact of electrical field and electrogenerated oxidants on algal inhibition, and we investigated the production of electrogenerated reactive species and their contributions to the inhibition of Microcystis aeruginosa (M. aeruginosa) in simulated surface water with low Cl⁻ concentrations (< 18 mg/L). We developed a kinetic model to simulates the concentrations of chlorines and H₂O₂. The results showed that electrical field and electrogenerated oxidants were both important contributors to algal inhibition during electrochemical oxidation treatment. The Ti/RuO₂ anode mainly generates chlorines and H₂O₂ from Cl⁻ and water. During the electrolysis at current density of 20 mA/cm², when initial Cl⁻ concentrations increased from 0 to 18 mg/L (0–5.07 × 10⁻⁴ mol/L), the chlorines increased from 0 to 3.62 × 10⁻⁶ mol/L, and the H₂O₂ concentration decreased from 3.68 × 10⁻⁶ to 1.15 × 10⁻⁶ mol/L. Our model made decent predictions of other Cl⁻ concentrations by comparing with experiment data which validated the rationality of this modeling approach. The electrogenerated chlorine species were more effective than H₂O₂ at an initial Cl⁻ concentration of 18 mg/L.