Three-dimensional porous Co and N co-doped carbon efficiently activates peroxymonosulfate to enhance sulfamethoxazole degradation

Sulfamethoxazole (SMX), as a typical and widely-used antibiotic, its residue in the water environment poses a serious threat to human health and ecological balance. Herein, an environmentally friendly and cost-effective melamine sponge (MS) was utilized as a carrier for the preparation of three-dimensional (3D) porous cobalt and nitrogen co-doped carbon catalysts (Co-N/C) via an impregnation-pyrolysis method. This approach successfully yielded an easily recoverable Co-N/C@MS catalyst. By utilizing this catalyst to activate peroxymonosulfate (PMS), efficient degradation and purification of wastewater containing SMX were achieved. The experimental results showed that the Co-N/C@MS/PMS system achieved 98.39 % degradation efficiency, attributed to the sponge substrate's high pore structure allowing uniform catalyst dispersion. After four cycles, the system remained stable, addressing traditional powder catalysts' recovery and loss issues. Mechanistic studies revealed that C O, pyrrolic N, and Co 2 + are the primary active sites in Co-N/C@MS for PMS activation. Both radical (primarily SO 4 ·- ) and non-radical (mainly 1 O 2 ) pathways contribute to SMX degradation, with the latter pathways playing a dominant role. The optimal design and performance evaluation conducted in this study offer a novel perspective on the application of recyclable flake catalyst materials for persulfate purification of organic wastewater.