Recent advances in electrochemical flow reactors used in advanced oxidation processes: A critical review

This communication reviews recent advances in the design of electrochemical flow reactors used in water treatment by EAOPs. The performance of different reactor configurations, such as the press-filter type, parallel plates open to the atmosphere, RCEs, and three-dimensional electrode cells, are analyzed with examples during the degradation or mineralization of POPs. The EAOPs reviewed here are the AO, EF, PEF, active chlorine-based PEF-like, and E-peroxone. Moreover, the excellent performance of hybrid processes coupling EAOPs with adsorption, electrocoagulation, and biotechnological processes are rigorously examined. This review also analyzes successful cases of industrial EAOPs and hybrid processes using pilot-scale electrochemical reactors, emphasizing the importance of employing flow reactors on a lab scale before the pilot scale. Some recommendations for characterizing the reaction environment regarding non-ideal electrolyte flow dispersion, mass transport, and current distribution in the laboratory or pre-pilot scale reactors are exemplified with experimental data and CFD simulations from many worldwide research groups. Finally, the challenges in designing electrochemical flow reactors for EAOPs are presented.