The removal mechanism of PPCPs in the electro-activated peroxymonosulfate system coupled with nitrogen-doped carbon nanotube membrane electrodes

Pharmaceuticals and personal care products (PPCPs) are refractory emerging organic pollutants, and clofibric acid (CA) is a typical poorly biodegradable representative. Herein, a nitrogen-doped carbon nanotube (N-CNT) tubular ceramic membrane electrode was fabricated for electro-activated peroxymonosulfate (EA-PMS) degradation of CA, with systematic optimization of preparation and operational conditions. Nitrogen doping introduced pyrrolic/graphitic N active sites and increased structural defects, while the tubular configuration intensified mass transfer. The optimized electrode achieved > 90% CA removal within 30 min, maintained > 95% efficiency over 11 cycles, and exhibited broad-spectrum degradation for typical PPCPs, with low EE/O (0.0417 kWh m -3 order -1 ) and high PMS utilization (84.3%). Singlet oxygen ( 1 O 2 ) was the dominant reactive oxygen species, driving CA degradation via synergistic radical/non-radical oxidation. Three CA degradation pathways were elucidated by HPLC-MS, and ECOSAR simulations confirmed reduced aquatic toxicity of its intermediates. This work develops a high-performance EA-PMS electrocatalytic membrane system, providing a scalable platform for advanced treatment and risk control of trace PPCPs in water.