Electrochemical system with moderate ozone generation and catalytic enhancement for efficient organic wastewater...

Hydroxyl radical (•OH)-mediated electrochemical anodic oxidation (AO) is an efficient approach for the organic wastewater treatment. However, its practical application is constrained by energy-intensive demand due to the high potential required for •OH generation (E⁰ = 2.73 V). To address this challenge, we propose an integrated electrochemical in-situ ozone generation synergistic catalytic ozonation (EOCO) system to effectively reduce energy consumption, wherein ozone is generated on an Sb-SnO₂ anode and catalytically decomposed to •OH and ¹O₂ within a Mn_xCu_1-xO catalytic layer. Rather than pursuing high ozone concentrations output, the system maintains a moderate yet sustained ozone concentration to match downstream catalytic activation. Benefiting from the lower ozone generation potential (E⁰ = 1.51 V) and subsequent spontaneous catalytic ozonation, the system achieves phenol removal efficiencies comparable to •OH-mediated AO using a boron-doped diamond (BDD) electrode, with a 36.2 % reduction in energy consumption. In long-term treatment of acidic salicylic acid manufacturing wastewater, the system consistently maintains over 90 % total organic carbon removal over 350 h, demonstrating excellent operational stability. This work presents a practical and energy-efficient solution for sustainable treatment of organic industrial wastewater.