Interface-engineering induced medical wastewater purification and ammonia recovery via selective hydroxyl radical...

The activation efficiency of oxidants is a core determinant of the economic viability and operational feasibility of electrochemical technologies for medical wastewater purification. To address this issue, we develop a high-efficiency electro-Fenton like system based on collaborative interface engineering between plastic solid waste-derived defect-rich carbon materials and α-Fe₂O₃. By modulating the interfacial electronic structure to influence the *OOH binding energy, the generation of H₂O₂ is promoted. Meanwhile, the incorporation of α-Fe₂O₃ strengthens the adsorption of *HOOH intermediates and significantly enhances the activation of H₂O₂ to ·OH. The catalytic system exhibits a purification rate of 0.74 min^-1, which is 14 times higher than that of the system without interfacial engineering. The high catalytic rate of the systems accelerate oxidant activation, maximizing water treatment cost-effectiveness. During the reaction process, approximately 50 % of the N species are stably and selectively converted into the reusable ammonia in wastewater containing sulfonamide antibiotics. It enables 98 % chemical oxygen demand removal within 60 min in real medical wastewater matrices. To scale up lab-based findings for practical engineering applications, a novel reactor with efficient powder catalyst utilization and recovery is developed, boosting purification performance while reducing catalyst attrition. The integrated reactor features an economic cost of $32.2 m^-2, with each electrode costing only 1/36 that of a platinum-plated counterpart, and the energy consumption per stage as low as 0.05 kWh·m^-3. Additionally, it achieves a 21 % increase in ammonia conversion efficiency. This work thus proposes a promising strategy for sustainable environmental governance and resource recovery in electro-Fenton-like systems.