Preparation Of Ordered Spherical Mesoporous ZnO Supported Fe-Cu-Zr Composite Catalyst And Its Degradation Of Butyl Acetate

Volatile organic compounds（VOCs）pollute the atmosphere and endanger human health.It is a hot spot for environmental protection research to seek efficient VOCs.In this paper,the preparation method of ordered spherical mesoporous ZnO-loaded Fe-Cu-Zr composite catalyst was studied.The physicochemical properties of the catalyst were investigated by various characterization methods.The catalyst（ZnO-3M）was studied under different degradation factors.The degradation rate of esters was investigated by characterizing the changes before and after the catalyst and detecting the reaction intermediates and final products.The main conclusions are as follows:（1）Comparative study on the degradation of butyl acetate by the catalyst prepared by the alkothermic method and the sol-gel method,it is concluded that the catalyst prepared by the alcohol-heating method has a more fluffy structure and a better crystal plane structure,showing an orderly spherical mesopores.The structure has a larger specific surface area and the catalytic degradation of butyl acetate at a low temperature is better.The ZnO/（Fe-Cu-Zr=1:1:2）prepared by the aromathermal method（abbreviated as ZnO-3M）has a degradation rate of 35%of butyl acetate at an initial concentration of 500 ppm at room temperature（25°C）,T₅₀=116°C,T₉₀=200°C,completely removed at 270°C,with good low temperature catalytic activity.（2）Different molar ratio active components have a significant effect on the catalyst structure and catalytic activity.It is found that with the increase of zirconium content,the unit cell size of the carrier becomes larger,the diffraction peak peak increases,and the electron density increases,the binding energy becomes lower,and the redox of the catalyst is enhanced,wherein ZnO/（Fe-Cu-Zr=1:1:2）The highest catalytic activity.The catalytic activity of the catalyst increases first and then decreases with the increase of calcination temperature,and the specific surface area and dispersion are also the same.By increasing the temperature from350°C to 450°C by XPS analysis,the crystallinity of iron oxide becomes high,which inducesγ-Fe₂O₃ to becomeα-Fe₂O₃ crystal.When rising to 550°C,the diffraction peaks of Fe₂O₃ and ZnO are weakened,and the binding energy becomes large.The catalyst has the highest activity at a calcination temperature of 450°C.（3）Catalytic oxidation The degradation rate of butyl acetate decreased as the concentration before the reaction increases,space velocity and relative humidity,and increased with the increase of oxygen ratio.At an initial concentration of 500 ppm,a space velocity of 9000 h^-1,an oxygen ratio of 20%,and a relative humidity of 5%,the degradation rate of ZnO-3M to butyl acetate was as high as 100%at 270°C,and the conversion rate of CO₂ was It is 96%.（4）By characterizing the catalyst before and after the reaction,and analyzing the products by GC-MS and GC,it is inferred that the catalyst catalyzes the oxidation of butyl acetate by two degradation pathways:one is that the butyl acetate molecule is adsorbed by a high-valent oxide,surface lattice oxygen,and adsorption.Oxygen is directly oxidized to CO₂and H₂O;the second is that butyl acetate generates excited CH₃COOC₄H₉ under thermal radiation,and then reacts with the hydroxyl group to generate a small amount of lower acid and lower carbon alcohol.The catalytic temperature is greater than 270℃,which is converted into CO₂ and H₂O.