Electrochemical advanced oxidation processes for water treatment: Reactive-species regulation, materials design, process coupling, and engineering translation

Electrochemical advanced oxidation processes (EAOPs) are promising for treating refractory organic pollutants, with electrocatalytic materials controlling reactive-species generation, reaction pathways, and process efficiency. Electrocatalytic materials for water treatment are evaluated through a unified framework integrating reactive-species regulation, electrode processes, electrode-material and architectural design, multiprocess coupling, and engineering implementation. Anodic oxidation, electro-Fenton processes, and electrochemical PMS/PDS activation are compared in terms of mechanisms, material requirements, by-product risks, and operating boundaries. Structure–activity relationships are examined from active-site and interfacial regulation to morphology, pore architecture, and effective electrode utilization, distinguishing intrinsic activity from architecture- and operation-dependent performance. Coupled photoelectrocatalytic, EF–PMS/PDS, paired anodic–cathodic, bioelectrochemical, and resource-recovery systems are also assessed. Five interconnected bottlenecks are identified: causal determination of operando active states and pathways; transferable relationships across material, electrode, and reactor scales; spatial coordination of oxidant generation, activation, and pollutant transport; long-term durability in complex water matrices; and consistent integration of performance testing with techno-economic analysis and life-cycle assessment. Engineering challenges involving scale-up, continuous flow, electrode aging, and realistic wastewater validation are evaluated, and a staged framework linking mechanistic investigation, material–reactor co-design, real-water testing, and economic and environmental assessment is proposed. Practical implementation will require controllable reaction pathways, scalable active-site utilization, durable electrode–reactor configurations, and standardized evaluation under realistic conditions.