Overcoming catalyst deactivation with in-situ electrochemical regeneration in packed-bed reactors enabling long-lived wastewater purification.

Heterogeneous advanced oxidation processes (HG-AOPs) can efficiently remove persistent pollutants but are constrained by catalyst deactivation from polymeric deposits and by energy- and chemical-intensive regeneration. We report a conductive packed-bed reactor that couples continuous treatment with in-situ electrochemical regeneration, maintaining high pollutant removal across diverse contaminants and complex matrices. Upon loss of activity due to catalyst deactivation, applying a mild current with low-cost H2O2 restores performance without reactor downtime. Mechanistic analyses show that electrochemical modulation lowers surface lipophobicity and weakens the interaction between polymeric products and the catalyst, enabling their desorption. Meanwhile, electrogenerated •OH promotes the coupling of residual phenolic polymers into insoluble aggregates and mineralizes quinoid compounds, recovering interfacial mass and electron transfer. Industrial coking wastewater can be continuously treated using a series-parallel reactor system, which alternates between oxidation and regeneration phases. This approach maintains over 80% total organic carbon removal efficiency for more than 300 hours of operation. Compared with conventional advanced oxidation processes, this strategy reduces operating costs by ~68%, minimizes external chemical inputs, and avoids high-temperature regeneration. The reactor architecture and regeneration logic are scalable, compatible with distributed deployments, and readily retrofittable to existing units, providing a sustainable pathway to extend catalyst lifetimes, lower resource intensity, and advance next-generation oxidation technologies.