Carbon-doped defect MoS2 co-catalytic Fe3+/peroxymonosulfate process for efficient sulfadiazine degradation: Accelerating Fe3+/Fe2+ cycle and 1O2 dominated oxidation

In order to accelerate Fe3+/Fe2+ cycle and boost singlet oxygen (1O2) generation in peroxymonosulfate (PMS) Fenton-like system, a co-catalyst of defect MoS2 was prepared by C doping and C2-MoS2/Fe3+/PMS system was structured. The removal efficiency of sulfadiazine (SDZ) antibiotics was nearly 100 % in 10 min in the system under the appropriate conditions ([co-catalysts] = 0.2 g/L, [PMS] = 0.1 mM, [Fe3+] = 0.4 mM, pH 3.5), and the reaction rate constant was 4.6 times that of Fe3+/PMS system. C doping MoS2 could induce phase transition, yield more sulfur defects, and expedite electron transfer. Besides, exposed Mo4+ sites on C2-MoS2 could significantly enhance the regeneration and stability of Fe2+ and further promote the activation of PMS. ·OH, SO4·-, and 1O2 were responsible for SDZ degradation in the system. Notably, 1O2 generation was efficiently promoted by sulfur defects and CO sites on C2-MoS2, and 1O2 played the main role in SDZ degradation. Therefore, this co-catalytic system exhibited great anti-interference and stability, and organic contaminants could be efficiently and stably degraded in a 14-day long-term experiment. This work provides a new approach for improving the co-catalytic performance of MoS2 for Fe3+ mediated Fenton-like technology, and offers a promising antibiotic pollutant removal strategy.