High-efficiency removal of organic pollutants, antibiotic resistant bacteria and resistance genes by a photocatalysis-self-Fenton system based on S, K co-doped g-C3N4 nanosheets

Herein, S, K co-doped g-C3N4 nanosheets (SKCN) based photocatalysis-self-Fenton (PSF) system with strong oxidation capacity and fast mineralization efficiency was constructed to eliminate organic pollutants, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) under visible light. The bisphenol A degradation rate of SKCN-PSF system (0.10 min−1) was 18.9 and 43.5 times as that of bulk g-C3N4-photocatalysis and Fenton systems, respectively, while the corresponding mineralization efficiency (56.4 %) was enhanced by 7.2 and 12.8 times, respectively. Meanwhile, the inactivation ratios of SKCN-PSF system reached 98.5 % for sulfonamide ARB within 60 min and 98.2 % for sulfonamide ARGs within 2 h, which were much greater than those of SKCN-photocatalysis (66.8 % and 82.6 %) and Fenton (24.7 % and 27.1 %) systems. The high-efficiency removal performance of SKCN-PSF system was owing to the S, K co-doping structure and nanosheet morphology of SKCN for improving the photocatalytic H2O2 production to promote the self-Fenton reaction, as well as the synergetic effect between photocatalysis and Fenton reactions for increasing the generation of hydroxyl radicals and releasing more holes. This work exhibits a promising potential of g-C3N4-PSF system for the effective elimination of various chemical and biological pollutants.