Degradation Of Sulfamerazine By NF/CN-TF/Ti₄O₇ Electrochemical System And Its Mechanism

China is a big country in the production and use of antibiotics.Antibiotics released into the receiving environment can lead to the production of resistance genes and resistant bacteria,resulting in reduced or ineffective drug efficacy.Reducing the amount of antibiotics that enter the environment due to human factors and reducing environmental ecological risks are hot topics in environmental research.Sulfonamides account for more than 5%of total antibiotic use in China.The increasing production and use of sulfamerazine?SMR?has led to an increasing number of refractory wastewaters.The electric-Fenton technology and anodizing technology in advanced catalytic oxidation technology have the advantages of low selectivity and good treatment effect in treating antibiotic wastewater.It is a hotspot of scholars at home and abroad,and the related research focuses on the research and development of anode materials for cathode and anodizing system of electric Fenton system.Nitrogen-modified porous carbon materials are hotspots in cathode materials research.At the same time,titanium black materials also have good research prospects in anode materials research.Therefore,a carbon-nitrogen modified foamed nickel?NF/CN?cathode and a titania modified titanium foam?TF/Ti₄O₇?anode were used to construct an electric Fenton-anodizing electrochemical system,and the SMR degradation mechanism was studied.Utilizing p-phenylenediamine to form a nitrogen-doped porous carbon material.The NF/CN cathode is prepared by rolling it on a foamed nickel substrate.The SEM results show that the prepared electrode has a stacked spherical microscopic morphology.Characterization of materials such as XPS and FTIR indicated that functional groups containing nitrogen and oxygen such as C?O?-OC and C-N/C=N were successfully modified on the electrode surface.LSV analysis shows that the electrode has stronger electrochemical reactivity than the substrate.The RDE experiment further proves that it still has a strong selectivity for two-electron oxygen reduction reaction at a potential of 0.60 V.EIS analysis showed that the interface electron transfer resistance decreased from 95.7?to 19.7?.The cathode is more resistant to H₂O₂ and iron reduction than the foamed nickel substrate,graphite and carbon felt.Optimal H₂O₂ production at a current density of 10 mA/cm².At the same time,H₂O₂ production was 16 times that before modification.At the same time,the iron reduction ability of the cathode is also enhanced.The titanium black?Ti₄O₇?material was successfully modified on the surface of the foamed titanium by laser jet technique to form a TF/Ti₄O₇ anode.SEM results show that it has a complex pore structure.XPS,XRD,FTIR and other experiments have proved that the surface of the electrode Ti₄O₇ is of high purity.LSV analysis showed that the prepared TF/Ti₄O₇ anode had a higher oxygen evolution potential?1.56 V vs.SCE?.EIS also reflects that its charge transfer resistance drop is reduced from 43.4?of the substrate to 11.2?.The polarization curves in different concentrations of SMR solution prove that the anodizing system formed by it has direct oxidation to SMR.ESR,TA capture,·OH experiments,etc.also demonstrated its outstanding indirect oxidation capacity?about 0.62 times that of the finished BDD electrode?.Reversing the passivated anode by electrical reduction.The doubling effect can be obtained by renaturation for 30 min at a current density of 50.0 mA/cm².The electric Fenton-anodizing electrochemical system constructed by NF/CN-TF/Ti₄O₇ has the best effect on the degradation of SMR with current density 10mA/cm²,initial Fe²⁺concentration 0.250 mmol/L and initial pH=2.0.The removal rate of SMR reached 99.48%within 8 h,and the mineralization rate reached 48.04%.The electric Fenton mechanism is the main way to degrade pollutants in electrochemical systems.The contribution rate is 71.60%.Analysis shows the degradation path of SMR in the electrochemical system.Including benzene ring hydroxylation substituted amino oxidation,the S-N???bond cleavage in the sulfonamide structure and the S-C???bond cleavage in the sulfonamide structure are three ways.The NF/CN-TF/Ti₄O₇ electrochemical system successfully constructed in this study has a good degradation effect on SMR.The analysis of the degradation mechanism provides a theoretical basis for the treatment of actual wastewater.