| As a chemical synthetic fiber,polyester is widely used in daily textiles and production and life due to its high strength and excellent physical and mechanical properties.However,it is difficult to degrade polyester in a short period of time,resulting in a large amount of waste polyester.,Exacerbating the problem of environmental pollution.At present,the method of alcoholysis of waste polyester with excess glycol is more common.However,the polyester alcoholysis solution after the reaction contains a large amount of ethylene glycol remaining from the reaction,some dyes,and other impurities,and direct discharge will cause pollution.Environment,if reused for polyester degradation,it will affect the purity of the degradation products.Therefore,realizing the effective decolorization of the alcoholysis solution has practical significance and application value.In recent years,advanced oxidation technology has been gradually applied in dye removal,and scholars have done more research on dispersed electrodes.The so-called dispersed electrode structure refers to the addition of a large number of dispersed particles(dispersed electrode)between the two basic electrodes to increase the area of action between the dispersed electrode and pollutants,thereby achieving a better decolorization effect.However,since the dispersed electrodes are mostly in powder state,there is a problem of electrode loss during the recycling process.In order to solve the above problems,some scholars have prepared fixed electrodes.Due to the fixing effect,the fixed electrode is more easily recyclable than the dispersed electrode.However,due to the limited contact area between the fixed electrode and the contaminants,there is also the problem of low decolorization rate.In the process of decolorization of polyester alcoholysis solution,in order to achieve efficient decolorization and easy recovery.In this paper,ZnO and CuO have the characteristics of pn junctions with different band gap widths.By fixing ZnO and CuO layer by layer to the surface of porous Ti,a fixed electrode of ZnO and CuO modified porous Ti(referred to as porous Ti/ZnO/CuO electrode).Because the p-n junction of ZnO and CuO can reduce the recombination of photo-generated electron-hole pairs and improve the photocatalytic activity,the porous Ti/ZnO/CuO electrode has a better catalytic effect.The research results show that in the decolorization experiment using Disperse Red 60 as a simulated pollutant,the decolorization rate can reach more than 95%.And because ZnO and CuO can be fixed on the porous Ti electrode,the problem of loss during the recovery process of the dispersed electrode is solved.In addition,this thesis also investigated the influence of various factors in the decolorization process on the decolorization,and finally explored the decolorization mechanism.The main research contents are as follows:The subject first took the n-type semiconductor material ZnO as the modifier,and prepared ZnO modified porous Ti electrode(referred to as porous Ti/ZnO electrode)by changing the reaction time of ZnO in the autoclave,namely porous Ti/ZnO(4 h)(rod-shaped),Porous Ti/ZnO(8 h)(flower ball),porous Ti/ZnO(12 h)(sheet)electrode.Characterize the appearance and morphology of ZnO by scanning electron microscope(SEM),characterize the crystal lattice and microstructure of ZnO by transmission electron microscope(TEM),and characterize its peak diffraction intensity by X-diffraction line(XRD);different morphologies The electrochemical performance of ZnO is characterized by linear scan(LSV)and electrochemical impedance spectroscopy(EIS).Among them,the electrochemical test results show that the electrochemical performance of porous Ti/ZnO(4 h)electrodes is better than porous Ti/ZnO(8 h)and porous Ti/ZnO(12 h)electrodes.In order to compare the decolorization rate of ZnO modified porous Ti electrodes with different morphologies,the porous Ti electrodes modified with ZnO with different morphologies were subjected to photocatalytic decolorization under visible light and ultraviolet light respectively.The experimental results show that the porous Ti/ZnO(4 h)electrode has a higher decolorization rate under ultraviolet light irradiation.In order to determine the influence of rod-shaped ZnO(reaction time of 4 h)on the decolorization rate,this article explored the effect of different amounts of zinc source on the decolorization rate.The amount of zinc source was set to0.0003 mol,0.0006 mol,0.0009 mol,0.0012 mol,0.0015 mol,0.0018 mol,the research results show that when the amount of zinc source is 0.0012 mol(the loading amount of rod-shaped ZnO on the porous Ti electrode is 6.4 mg),the decolorization rate of the porous Ti/ZnO(4 h)electrode is higher,and the decolorization The rate is 35%.Secondly,it explored the modification of porous Ti electrode with the p-type semiconductor material CuO as the modifier.By changing the p H value during the hydrothermal reaction,under the experimental conditions of Cu Cl2·2H2O as the copper source and NH3·H2O as the alkali agent,The modification of porous Ti electrode by CuO(referred to as porous Ti/CuO electrode)was realized,and porous Ti/CuO(p H=10)(flower shape),porous Ti/CuO(p H=12)(maple leaf shape),porous Ti/CuO(p H=10)(flower shape),porous Ti/CuO(p H=12)Ti/CuO(p H=14)(belt-shaped)electrode;use SEM,XRD,TEM to characterize the microstructure of three different morphologies of CuO,and use ultraviolet spectrophotometer(UV-vis)and linear scan(LSV)at the same time The light absorption capacity and electrochemical performance of porous Ti/CuO(p H=10),porous Ti/CuO(p H=12)and porous Ti/CuO(p H=14)electrodes were tested and analyzed.The test results show that the porous Ti/CuO(p H=10)electrode exhibits stronger absorption capacity for visible light;the LSV curve shows that the sensitivity of the porous Ti/CuO(p H=10)electrode to current response is better than that of the porous Ti/CuO(PH=12),porous Ti/CuO(p H=14)electrode.In order to compare the decolorization rate of CuO modified porous Ti electrodes with different morphologies,the porous Ti electrodes modified with different morphologies CuO were subjected to photocatalytic decolorization under visible light and ultraviolet light respectively.After comparison,it is found that the photocatalytic activity of the porous Ti/CuO(p H=10)electrode is higher under the irradiation of visible light and ultraviolet light respectively;when exploring the influence of CuO loading on the decolorization rate,when the amount of copper source is 0.005 Within the range of ~0.03 mol,the mass of CuO loaded on the porous Ti electrode is 2.0 mg,4.1 mg,6.1 mg,8.2 mg,10.2 mg,12.3 mg,respectively.The photocatalytic decolorization experiment shows that when the porous Ti electrode is loaded with CuO mass of 10.2 mg(When the amount of copper source is 0.025 mol),the photocatalytic effect is better,and the decolorization rate can reach 49%.Finally,according to the above experimental results,the porous Ti/ZnO(4 h)and porous Ti/CuO(p H=10)electrodes have better photocatalytic effects.Here,ZnO reacted in an autoclave for 4 h and the reaction time The CuO with a p H value of 10 modifies the porous Ti electrode by constructing a heterojunction to prepare ZnO and CuO modified porous Ti electrodes(referred to as porous Ti/ZnO/CuO electrodes).Using scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),X-ray energy spectrometer(EDS),specific surface area tester(BET),the morphology,element and pore size distribution were analyzed respectively.Characterization,the photoelectric properties of porous Ti/ZnO/CuO electrodes were tested by linear scan(LSV),cyclic voltammetry(CV)and photoelectric-time curve in the electrochemical workstation.After testing,it is found that the photoelectrochemical performance of the porous Ti/ZnO/CuO electrode is better than that of a single porous Ti/ZnO and porous Ti/CuO electrode.In addition,the photoelectrochemical performance of porous Ti/ZnO/CuO electrode was used to decolorize the alcoholysis solution by photoelectrocatalysis.The experiment explored the influence of applied voltage,electrolytic salt concentration,p H value,etc.on the decolorization rate.The experimental results showed that: Under the experimental conditions that the voltage is 18 V,the electrolytic salt concentration is 1.2 g/L,the p H value is 5,and the initial dye concentration is 25 mg/L,the decolorization rate can reach more than 95% after photoelectric catalysis is carried out for 120 minutes;The stability,decolorization kinetics and decolorization mechanism of Ti/ZnO/CuO electrodes were analyzed. |
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