ZIF-67@ZIF-8 derived Co/Zn bimetallic particle electrodes activating peroxymonosulfate for sulfamethoxazole degradation in a three-dimensional electrochemical system

In this study, a three-dimensional electrochemical advanced oxidation process based on peroxymonosulfate (3D PMS-EAOP) system was established to address the environmental pollution caused by antibiotic contaminants. Concurrently, hollow-shell Co 3 O 4 @ZnO/C was designed via a metal-organic framework (MOF)-on-MOF strategy integrated with polypyrrole (PPy) to serve as particulate electrodes (PEs). The confinement effect of this material synergized with the structural advantages of 3D electrochemical reactor, endowing the system with both excellent reaction kinetics and low energy consumption. At a low current density of 6 mA·cm −2 , the system achieved 100% sulfamethoxazole (SMX) removal within 15 min ( k obs = 0.3534 min −1 ) which was 5.85-fold higher than without an electric field, while the energy consumption (EEC = 0.144 kWh·m −3 ) was 1–2 orders of magnitude lower than the reported systems. Co sites acted as the primary active centers for PMS activation, while the external electric field promoted the Co 3+ /Co 2+ redox cycle, thereby sustaining efficient PMS activation and the production of various reactive oxygen species. The 1 O 2 -mediated non-radical pathway and SO 4 •− /•OH-mediated radical pathway synergistically drove SMX degradation. Density functional theory calculations revealed that an external electric field precisely regulated PMS activation by enhancing the adsorption energy between PMS and the catalyst, lowering its activation energy barrier, and promoting charge transfer. Finally, seed germination experiments demonstrated that the toxicity of the treated effluent was significantly reduced, indicating robust ecological safety. In summary, this study provides an efficient, controllable, and low-energy technical route for the remediation of water environment.