Highly efficient elimination performance of graphene/supramolecular porphyrin-based photocatalysis-self-Fenton system towards sulfonamide antibiotics, resistant bacteria and resistance genes

Herein, a photocatalysis-self-Fenton (PSF) system, based on reduced graphene oxide/supramolecular porphyrin (rGO/SA-TCPP) photocatalyst with high H2O2 yield and Fe3+, was constructed to remove the sulfonamide antibiotics, antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in environmental water. The sulfadimethoxine degradation rate of rGO/SA-TCPP-PSF system was 7.6 and 17.7 times higher than those of SA-TCPP-photocatalysis and Fenton systems, while the corresponding TOC removal rate was 6.9 and 14.4 times higher, respectively. Furthermore, the removal rates within 4 h of rGO/SA-TCPP-PSF system towards the sulfonamide ARB and ARGs were 100.0% and 99.6%, respectively, which were much higher than those of SA-TCPP-photocatalysis system (42.8% and 25.2%) and Fenton system (10.7% and 4.0%). The remarkably efficient elimination performance of rGO/SA-TCPP-PSF system were not only attributed to the incorporation between SA-TCPP and rGO for boosting the H2O2 production to trigger the self-Fenton reaction, but also owing to the synergistic effect between photocatalysis and Fenton reactions for increasing the production of •OH and releasing more free photogenerated holes. After the treatment of rGO/SA-TCPP-PSF system with strong oxidation capacity and high mineralization efficiency, sulfonamide antibiotics could be thoroughly degraded and mineralized into harmless small molecules, while ARB and ARGs could be completely inactivated and prevented from regeneration via damaging the genomic DNA. This research introduces a novel approach for developing a high-efficiency PSF system to address antibiotic resistance contamination in water environment.