Engineering sulfur vacancies on Mo-doped FeS2 nanosheets grown on activated carbon fibers enhances peroxymonosulfate activation for efficient elimination of sulfamethazine, antibiotic resistant bacteria and antibiotic resistance genes: The dominant role of singlet oxygen

The widespread of antibiotics will induce the generation of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), causing threats to human health. Therefore, developing a green and efficient synchronous removal technology for the removal of antibiotics, ARB and ARGs is urgent. In this study, Mo doped FeS2 nanosheet with rich sulfur vacancies (SVs) grown on activated carbon fibers was successfully synthesized and employed as a PMS activator to remove sulfamethazine (SMT), ARB and ARGs in aqueous solution. Mo-FeS2/ACFs-0.1 (MFAs-0.1, the molar ratio of Mo/Fe is 0.1) showed high performance for PMS activation, and 99.7 % SMT was removed in 60 min (250 mg/L MFAs-0.1, 0.3 g/L PMS, initial pH = 5.5). In addition, low reagent doses of MFAs-0.1 catalyst (250 mg/L) and PMS (0.5 g/L) were found to be efficient for removing 7.25-log of ARB within 30 min and restraining conjugative transfer of ARGs. Singlet oxygen (1O2) was identified as the primary reactive oxygen species for SMT degradation and ARB inactivation. Meanwhile, the integration of Mo- doping with SVs could optimize the electronic structure, generating electron-rich and highly active regions. This facilitates the adsorption of PMS onto the Fe site and boosts electrons transfer from FeS2 to PMS, as indicated by density functional theory (DFT) calculations. Overall, this study demonstrated that the MFAs-0.1 based heterogeneous system was an economically "one stop" treatment process for the removal of biological and chemical contaminants. In addition, it would provide a new insight into the fabrication of FeS2 composites-based PMS activator.