Integration of electrochemical oxidation and photocatalysis for treating pharmaceutical residues in wastewater under varying environmental conditions

Pharmaceutical residues have emerged as persistent micropollutants in aquatic ecosystems, posing ecological, toxicological, and public health challenges due to their bioaccumulation and resistance to conventional wastewater treatment. Advanced oxidation processes (AOPs) have gained prominence for degrading such complex compounds, yet individual techniques often suffer from operational inefficiencies, incomplete mineralization, or high energy demands. This study explores the integration of electrochemical oxidation (EO) and photocatalysis as a synergistic treatment pathway capable of addressing these limitations under variable environmental conditions. The hybrid system combines the anodic generation of reactive oxygen species (•OH, O₂•–) with photoexcited semiconductor catalysts such as TiO₂ or doped ZnO, enabling simultaneous oxidation and photodegradation of pharmaceutical contaminants. The integration enhances electron–hole separation, improves mass transfer, and extends the oxidative potential beyond either process alone. Experimental simulations under varying pH, temperature, and light intensity demonstrate that the combined EO–photocatalytic process achieves higher degradation efficiency and total organic carbon (TOC) removal than standalone systems. Mechanistic analysis reveals that environmental conditions critically influence radical formation kinetics, electrode stability, and catalyst photoreactivity, thereby dictating the overall mineralization rate. Furthermore, the process exhibits resilience against matrix interferences such as chloride, bicarbonate, and natural organic matter. The study concludes that optimized hybrid EO–photocatalytic configurations represent a scalable and sustainable route for removing persistent pharmaceuticals from wastewater, contributing to circular water management and pollution mitigation. Future work should focus on energy recovery, reactor design optimization, and real effluent validation to ensure full-scale applicability in diverse climatic contexts.