Preparation And Application Of Silver Modified Magnetic Photocatalyst

Today,the chemical industry and agriculture are two important components of the national economy.The discharged industrial wastewater contains high-color,highly toxic dyes and aromatic nitro compounds,which seriously affects the cleanliness of natural water bodies and endangers human drinking water safety.Immediate measures must be taken to solve the problem of water pollution.Heterogeneous photocatalytic oxidation technology uses solar light source,scanty energy deplete,moderate reaction requirements,and wide range of applications.It can effectively deal with water pollution problems,and can completely degrade organic pollutants in water into H₂O,CO₂ without generating secondary pollution.A single nano-semiconductor?TiO₂,ZnO?photocatalytic material has the advantages of wide sources,little cost,steady physical/chemical qualities,non toxicity,and perfect photocatalytic activity,but its own photo-generated carrier recombination rate is high,and its spectrum the response range is narrow,it is difficult to recover in suspension,and the loss rate is large.Therefore,under the premise of ensuring the controllable particle size and not impact catalytic activty,a monodisperse magnetic nano-composite photocatalyst Fe₃O4@ZnO@SiO₂?FZS?and Fe₃O₄@TiO₂@SiO₂?FTS?with core-shell structure was prepared by solvothermal method,sol-gel method and St?ber method.On this basis,the noble metal silver was modified to prepare FZS@AgNPs and FTS@AgNPs photocatalysts.By means of XRD,SEM-EDS,TEM,XPS,FTIR,VSM and other characterization methods,the phase,morphology,elemental composition,internal structure,and magnetic property of the FZS@AgNPs and FTS@AgNPs complex photocatalysts prepared under the optimum prerequisite can proceed analytical tests.In order to investigate the degradation effect of FZS@AgNPs composite photocatalyst on organic pollutants,this thesis selects 4-nitrophenol?4-NP?as the research object,and changes the different reaction conditions and optimizes the design scheme to maximize the degradation rate of 4-NP value.The outcome show that the FZS@AgNPs photocatalyst has high-efficiency catalytic activity.A 350W high-pressure mercury lamp is used to simulate the light source,photocatalytic reduction of 40 mL 4-NP(30 mg·L^-1,pH=6.7)solution,when the catalyst dosage is 3g/L,the conversion rate was up to 97.42%within 50 min of light.Recovery cycle test showed that the FZS@AgNPs photocatalyst didn't have obvious photocorrosion,and the conversion rate remained above 91.0%after 15 consecutive reactions.The catalyst loss rate was only 15%under the action of an external magnetic field,indicating that it has excellent photocatalytic stability and reusability.In this thesis,evaluation of the catalytic performance of FTS@AgNPs composite photocatalyst,a representative Rhodamine B?RhB?solution was selected for study.Through UV-Vis monitoring,using a 350 W high-pressure mercury lamp as the light source,photocatalytic degradation of 40 mL of RhB(30 mg·L^-1,pH=5.6)solution,when the catalyst dosage is 1 g/L,the degradation efficiency is as high as 96.22%within 2 h of light,which is 17.63%higher than the industrial P25,indication that the FTS@AgNPs photocatalysts has strong oxidation and catalytic efficiency.The reaction conditions remain unchanged,and the test is repeated 10 times in a row,the catalyst recovery was reset to 93.36%,and the degradation rate still reached 91.90%,showing high catalytic activity and cycle stability.The preparation method of the new silver-modified magnetic photocatalyst is simple and efficient,with regular morphology,good photochemical stability,and unique magnetic properties,which make it have practical application value and future in purifying industrial wastewater.