Study On The Removal Of Resistant Bacteria From Water By Iron-carbon Materials Synergistic With UVA/LED Activated Persulfat

The emergence of antibiotic resistance has aggravated the difficulty of treating pathogen-infected diseases,and the resulting antibiotic resistant bacteria（ARB）pose a huge threat to public health worldwide.The elimination of antibiotic resistance requires not only the inactivation of ARB,but also the effective containment of ARB reactivation and the risk of antibiotic resistance genes（ARGs）transmission.In this study,E.coli carrying RP4 plasmid was used as the research object to construct a ternary system composed of iron-carbon material（Fe/C）,ultraviolet（UVA/LED）and persulfate（PS）.The efficient removal of ARB in water was mainly achieved by activating PS to produce reactive oxygen species（ROS）with strong oxidizing properties.The removal effect of ARB under different factors was clarified,and its potential removal mechanism was explored.At the same time,the characteristics of ARB reactivation and ARGs transmission were evaluated,which provided data support for the removal of antibiotic resistance pollution in water based on PS advanced oxidation method.The characterization results showed that the Fe/C material had certain mesopores,loaded with iron,and its surface contained functional groups such as O-H,which were beneficial to the activation of PS.Suspended solid（SS）and various inorganic anions(Cl^-,HCO₃^-,SO₄^2-,NO₃^-)inhibited the removal of ARB.Under the optimal removal conditions of UV intensity 8.5m W/cm²,initial bacterial concentration 10⁶ CFU/m L,initial p H=5,PS dosage 1 m M,and Fe/C dosage 0.5 g/L,ARB could be completely removed within 40 min.Even after four cycles of the test,75%removal of ARB could still be achieved,and the stability was good.The removal mechanism of ARB involved UVA photooxidation,iron-carbon adsorption,and active oxygen oxidation.The leading role was active oxygen oxidation,and the inactivation ratio is as high as 90%.The analysis of cell detection showed that external stimulation（extracellular ROS attack）caused the production of intracellular ROS in ARB.The stronger the stimulation,the greater the relative change,and increased the cell membrane permeability.The contribution of each ROS in the reaction system was ¹O₂>·O₂^->·SO₄^->·OH.After adding¹O₂ quencher,the inactivation rate of ARB decreased by 90%.The investigation of ARB regeneration characteristics showed that ARB was not detected after dark repair for 2 h,and residual ROS could still inhibit ARB regeneration.The results of ARB transmission risk showed that there was no conjugation transfer and transformation in the water samples after treated by the ternary system.The results showed that the synergistic activation of PS by Fe/C and UVA/LED could effectively inactivate ARB and block the potential transmission risk of ARGs.