Efficient removal of dimethylacetamide through the activation of peroxymonosulfate in a continuous flow-through...

The cobalt-doped conductive carbon membrane (CoCM) with a single-atom Co-N₄ active structure was synthesized from activated carbon and ZIF-67 via compression molding and high-temperature carbonization. The effect of ZIF-67 doping (0-10 wt%) on CoCM's microstructure and performance was systematically studied. The optimal CoCM5 (5 wt% ZIF-67) showed a honeycomb pore structure (37.2 nm average pore diameter, 42.3 % porosity, 462.7 m²/g BET surface area) and maintained 5.8 MPa bending strength. Electrochemical tests confirmed CoCM5 had a much lower charge transfer resistance (1.67 Ω) than undoped CoCM0 (8.95 Ω), boosting peroxymonosulfate (PMS) activation. As the anode in a continuous flow-through electrocatalytic membrane reactor (ECMR), CoCM5 achieved 63.8 % degradation of 0.2 g/L dimethylacetamide (DMAc) at 2 V-1.5 times higher than the Fe-N₄ doped carbon membrane system. High-performance liquid chromatography identified N-methylacetamide and acetamide as key intermediates, verifying DMAc's stepwise N-demethylation. Density functional theory (DFT) and experiments revealed the core mechanism: the Co-N₄ structure (dominant active site) reduces PMS activation energy barrier to 0.39 eV (0.39 eV lower than CoCM0) and promotes electron transfer from Co(III) to PMS, generating 2.3 times more sulfate (SO₄^-) and hydroxyl (OH) radicals than CoCM0. This study provides a strategy for designing self-supported, stable metal‑nitrogen-doped carbon membranes and highlights ECMR's potential in solving low mass transfer and secondary contamination issues in refractory organic wastewater treatment.