Single atom Fe-dispersed graphitic carbon nitride (g-C3N4) as a highly efficient peroxymonosulfate photocatalytic activator for sulfamethoxazole degradation

A highly efficient single atom Fe-dispersed g-C3N4 catalyst with a Fe-N4 coordination structure for peroxymonosulfate (PMS) photocatalytic activation and sulfamethoxazole (SMX) degradation was synthesized. The dominant role of Fe single atoms in the activation of PMS and SMX removal was revealed, and the contribution of photo-generated electrons (e−) and holes (h+) to the enhanced catalytic performance of the catalyst in PMS activation was elucidated. Under visible light irradiation, 98.7% of the SMX with the initial concentration of 10 mg/L was quickly degraded within 6 min using 50 mg/L catalyst. The turnover efficiency (TOF) of the catalyst is as high as 5.27 min−1, which is 2–6 orders of magnitude higher than normal Fe-containing catalysts for SMX degradation. Moreover, this catalyst exhibits excellent stability and reusability. The dominating reaction active species involved in the degradation of SMX were identified, and the possible SMX degradation mechanism was proposed based on the detected degradation intermediates. This work provide a highly efficient visible light response single atom Fe catalyst for the sulfate radical-based advanced oxidation process.