Enhancement Of H₂O₂ Accumulation At Modified Gas Diffusion Electrodes And Its Utilization For Studying The Degradation Mechanism Of Sodium Sulfathiazole

When antibiotics enter the environment,they will not only be a challenge to the wastewater treatment system,but also difficult to decompose from the water environment,and may even induce drug-resistant bacteria and antibiotic resistance genes,leading to a huge threat to human health and ecological security.Electron-Fenton uses electric energy as a driving force to generate H₂O₂ in situ by cathodic oxygen reduction reaction（ORR）,which in turn induces·OH production,having the advantages of high oxidation Electron-Fentonficiency,green color,strong controllability,etc.In the exploration of Fenton,the next idea to increase the ficiency of the Electron-Fenton system is to load solid powder on the GDE.This project aims to improve the production of H₂O₂ and use it for STZ degradation by modifying GDE with a one-step synthetic carbon-nitrogen composite.Firstly,the carbon-nitrogen composites were successfully prepared and analyzed by RDE.The CN-GDE was prepared and the optimum ratio of carbon-nitrogen composite to carbon black was optimized to be 1/5.Experiments on the influencing factors of H₂O₂ show that the stronger the acidic conditions,the better the production of H₂O₂.The appropriate increase of current can increase the yield of H₂O₂.In order to achieve the best results of the system treatment of STZ,the reaction conditions were optimized,the optimum applied current was 30 mA,the pH was 3,and the initial ferrous concentration was 0.7 mmol/L.In order to further improve the oxidation ability of GDE and improve its degradation Electron-Fentonfect on STZ,cobalt carbon-nitrogen composites were prepared and characterized and analyzed with carbon-nitrogen composites.Through the comparison of H₂O₂ production capacity,ESR analysis,and cobalt ion dissolution test,it was proved that C_O-GDE reacted with Fenton reaction in the surface of electrochemical reaction.Recyclability experiments show that the cathode stability of C_O-GDE is much worse than that of CN-GDE.By comparing the scanning electron microscopy of the gas diffusion cathode before and after use,the surface corrosion of C_O-GDE is more serious than that of CN-GDE.It is verified that the ability to degrade STZ is better than CN-GDE and explores the mechanism of STZ degradation,including:the contribution of electric Fenton oxidation,anodization and like Fenton oxidation to STZ degradation,TOC and TN changes during STZ degradation,and STZ degradation process,changes in small and medium molecular organic acids,STZ degradation pathway analysis and toxicity studies in STZ degradation.In this study,CN-GDE with high Electron-Fentonficiency of H₂O₂ was successfully prepared by modified gas diffusion electrode,and cobalt was supported on this basis,which further improved the oxidation ability of the electrode and has a very significant effect on the degradation of STZ.In conlusion,it has good application value.