The Preparation Of Heterogeneous Fenton-like Catalysts And The Study On Their Catalytic Degradation Properties Based On SPR Effect

With the expansion and rapid development of industrial production,a large amount of organic pollutants exists in industrial wastewater,degradation of organic pollutants has become one of the important work of water treatment.The main research work of this paper is to combine the surface plasma（SPR）effect of precious metal with heterogeneous Fenton-like oxidation technology to improve the catalytic performance of the catalyst and improve the degradation rate for the treatment of organic pollutants in wastewater.Based on the SPR effect and the application status of Fenton-like oxidation technology,the following three aspects of research work were carried out in this paper:In the second chapter,Ag/CoFe₂O₄ composite catalyst was prepared and its catalytic degradation performance was studied.The Ag⁺in Ag NO₃ was reduced to Ag~0 by in-situ photoreduction method,and the Ag/CoFe₂O₄ composite catalyst was prepared by loading Ag NPs on the surface of CoFe₂O₄ nanoparticles.The effect of different Ag loading on the catalytic degradation of methylene blue（MB）under the visible light was studied,and the best Ag loading was found.The degradation rate of MB on CoFe₂O₄ increased from 57.4%to 96.3%under the same conditions after loading Ag.Then the factors affecting the performance of catalyst in the reaction process were investigated.The possible mechanism of the degradation of MB was proposed by combining the characterization results of the composite catalyst and the quenching experiments.The good stability of Ag/CoFe₂O₄ composite was verified by cyclic experiments.The experimental results show that SPR effect can significantly optimize the Fenton-like reaction effect,which will open up a developing path to improve the catalytic efficiency of various heterogeneous Fenton-like reaction catalysts.In the third chapter,Ag/Ag Cl was supported on the surface of CoFe₂O₄ nanoparticles by hydrothermal method to prepare a composite catalyst for the degradation of MB.The Ag/Ag Cl/CoFe₂O₄ composite catalysts with different load ratios were prepared by adjusting the ratio of reactants,and the best composite ratio was explored for catalytic degradation of MB under light.Comparing the catalytic effect of Ag/Ag Cl/CoFe₂O₄ composite material with pure CoFe₂O₄,it is found that the catalytic efficiency of the composite catalyst is 1.3 times that of pure CoFe₂O₄under the same condition,indicating that the combination of Ag/Ag Cl and CoFe₂O₄ can effectively improve the catalytic effect of CoFe₂O₄.By exploring the relationship among SPR effect of silver nanoparticles,photosensitizer Ag Cl and Fenton-like reaction,a possible mechanism for photoassisted Fenton-like reaction of Ag/Ag Cl/CoFe₂O₄ was proposed.In chapter 4 of this paper,Ag/ZIF-67 with different mass fractions of silver were prepared by photodeposition of Ag NPs on ZIF-67.Under the irradiation of halogen lamp and in the presence of PMS,the performance of the catalyst was tested with 50ml 10mg/L MB solution.The influence of different Ag loading on improving the catalytic performance of ZIF-67 was explored,and the amount of PMS was studied after the optimal loading was determined.The effects of Ag-loaded ZIF-67 on the activation of PMS were compared,and the active species were identified in combination with the capture experiment.The possible reaction mechanism was proposed.The experimental results show that SPR effect has a certain effect on the performance of heterogeneous Fenton reaction catalyst,which opens up a way for its application in advanced oxidation reaction and wastewater treatment.In this thesis,the SPR effect of noble metal Ag is combined with heterogeneous Fenton-like oxidation technology to prepare three composite catalysts based on Ag NPs.Through experiments,the effects of different experimental conditions such as natural light,p H value on the catalytic performance of composite catalysts are explored.Combined with capture experiments,the possible reaction mechanism is proposed,which provides a new research idea for the application of SPR effect in the field of heterogeneous Fenton-like reaction catalysis technology.