The Degradation Of Organic Pollutants By Activated Persulfate With Iron-based Materials

With the continuous innovation of advanced oxidation technology,more and more new advanced oxidation technologies,such as activated carbonate,persulfate and Fenton-like technology,are gradually being applied in the field of removal of refractory organic pollutants because of their high catalyst reaction efficiency and no secondary pollution.Among them,the advanced oxidation technology of activated persulfate has become a research hotspot in recent years because of the characteristics of mild reaction conditions.And iron-based materials have received extensive attention due to their environmental friendliness and low cost benefits of activating advanced oxidation technology to remove organic pollutants.In this paper,several iron-based materials are used as carriers to explore the catalytic degradation of organic pollutants by activated persulfate,which mainly includes the following researches:（1）Preparation of MOF-based ZnFe₂O₄ by solvothermal method to activate persulfate to degrade bisphenol AA series of MOF-based MFe₂O₄ magnetic spinel catalysts prepared by solvothermal method,degrading bisphenol A,found that ZnFe₂O₄ has the best catalytic activation persulfate activity compared to Co Fe₂O₄ and Ni Fe₂O₄ prepared by the same method.The results of the cycle test show that the catalyst has the advantages of strong magnetism and stability brought about by repeated use,making it promising for practical production.Free radical quenching results show that the catalyst belongs to the free radical reaction mechanism induced by sulfate radicals.Raman and XPS characterization results show that the abundant carbon defects of MOF-based ZnFe₂O₄crystals promote the advanced oxidation of sulfate.（2）Surface-regulated carbon nanotubes modified ZnFe₂O₄ to activate persulfate to degrade organic pollutantsBy combining CNTs with MOF structure of ZnFe₂O₄,it is found that the efficiency of degrading bisphenol A has been further improved.The introduction of CNTs reduces the lattice oxygen and oxygen vacancies of ZnFe₂O₄ crystals,and introduces more carbon defect points.Using high temperature and Ar atmosphere to control the surface defects of CNTs and then modify ZnFe₂O₄,it is found that the catalytic performance of the composite catalyst has been greatly improved.This is because the doping of CNTs-Ar changes the electron density near the metal ions,and the electron transfer rate is significantly increased.The conductivity of the catalyst itself facilitates the transfer of electrons from organic matter to persulfate.The FT-IR characterization results also show that the original lattice structure of ZnFe₂O₄ in the CNTs treated with Ar compound is broken,which promotes the transfer of electrons to PS.（3）Study on the degradation of organic pollutants by red mud activated persulfate.After the red mud to be recycled is activated by acid,it can dissolve a large amount of ferric ion-activated persulfate in an acidic environment.Because the red mud contains many metal oxides,the sintered structure at temperatures below 500°C is still stable,and the acidification after defect control the catalytic performance of red mud is slightly improved but not obvious.The ability to activate persulfate is greatly improved after the intervention of strong light,and the colored dyes are completely degraded in a short time.