Research Progress of Heterogeneous Electro-Fenton Process for Water Treatment: Key Factors and Optimization Strategies
Persistent organic pollutants (POPs) are ubiquitously detected in aquatic environments, and conventional treatment methods fail to achieve efficient degradation due to their structural stability and resistance to biological transformation. Heterogeneous electro-Fenton (HEF) technology, which generates H2O2 in situ via the two-electron oxygen reduction reaction (2e−ORR) and activates it to hydroxyl radicals (·OH) on solid catalysts, has emerged as a promising advanced oxidation process. HEF eliminates the need for external reagents, offers adjustable potential, and operates effectively across a broader pH range than classical Fenton, mitigating iron sludge production and secondary pollution. However, catalytic efficiency is significantly influenced by catalyst properties, solution pH, current density, and electrolyte type. Current research focuses on two main strategies: (1) developing high-performance bifunctional catalysts that simultaneously enhance 2e−ORR selectivity and H2O2-to-·OH conversion efficiency, and (2) constructing dual-cathode systems that spatially separate H2O2 generation and activation, thereby improving reaction synergy, reducing metal leaching, and enhancing electron utilization. Additionally, HEF can be coupled with electro-oxidation, persulfate activation, and UV irradiation to exploit synergistic effects, enhancing mineralization efficiency and reducing energy consumption. This paper systematically reviews the reaction mechanisms, key influencing factors, and optimization strategies of HEF, aiming to provide a theoretical basis and technical reference for its engineering application.