Combating microplastic pollution in water: the role and limits of electrochemical methods
摘要
Microplastics are persistent aquatic contaminants that resist conventional treatment methods. Electrochemical technologies, encompassing advanced oxidation processes, electrocoagulation, and electrokinetic separation, have attracted growing interest for microplastic remediation. Among these, electrochemical advanced oxidation processes offer the potential for near-complete polymer mineralization without secondary waste. However, literature data remain fragmented and inconsistent, with energy costs for microplastic treatment spanning three orders of magnitude, from ~ 10 to > 10,000 kWh/kg of microplastic. This review critically evaluates the current state of electrochemical microplastic oxidation, with emphasis on process efficiency, energy consumption, and analytical rigor. The analysis showed that most systems achieved only partial oxidation or surface modification rather than full mineralization, while current efficiency calculations were frequently unclear or absent. The absence of standardized characterization protocols and comprehensive mass balances severely hampers cross-study comparison. To address these shortcomings, a minimum methodological framework based on complementary analytical techniques is proposed to ensure reliable reporting of performance metrics. Mechanistically, future progress depends on overcoming the spatial constraints of interfacial oxidation through longer-lived oxidants and durable electrode materials. Since incremental parameter optimization offers limited gains, meaningful advancement requires hybridization of electrochemical advanced oxidation processes with complementary technologies, including photochemical, catalytic, and membrane-based processes, as well as reagent-enhanced systems. This review consolidates existing knowledge, exposes critical knowledge gaps, and provides a practical framework for transitioning electrochemical microplastic treatment from a laboratory concept to a scalable environmental technology.
Graphical Abstract