Activation of peroxymonosulfate using heterogeneous Fe-doped carbon-based catalyst to generate singlet oxygen for the degradation of sulfamethoxazole

Non -radical catalytic oxidation processes can eliminate refractory pollutants from wastewater containing complex substrates such as dissolved organic matter, but the production of selective non -radicals is challenging during the activation of peroxymonosulfate (PMS). Herein, a novel magnetic carbon -based catalyst (Fe 3 O 4 @CD- 8, where 8 represents an annealing temperature of 800 degree celsius) with N and Fe species as catalytic active sites was fabricated to remediate sulfamethoxazole (SMX)-containing water. It showed excellent SMX removal efficiency and facilitated singlet oxygen ( 1 O 2 ) production. The characterization results revealed that Fe 3 O 4 @CD-8 had a microscopically hierarchical pore structure and an overall core - shell-like structure. Due to its large specific surface area, N -containing species, and Fe nanoparticles, 0.1 g/L Fe 3 O 4 @CD-8 removed almost 100% SMX (24 min) and achieved a 44.1% mineralization (40 min) efficiency in the presence of 0.5 mM PMS. This catalytic system also maintained its removal performance in the presence of inorganic anions and humic acids and over a wide pH range of 3 - 11, showing good tolerance to various environmental factors. 1 O 2 was confirmed to be the predominant active species for SMX degradation using the Fe 3 O 4 @CD-8/PMS system. Density functional theory (DFT) calculations, intermediate monitoring, and toxicity evaluation demonstrated that SMX was transformed into low -toxicity molecules and completely mineralized into CO 2 and H 2 O. The addition of Fe nanoparticles enhanced PMS adsorption and facilitated the Fe(III)/Fe(II) redox cycle to accelerate the activation of PMS. This study provides new insights and strategies for the controlled production of non -radicals for remediating antibiotic -containing wastewater.