Study On Preparation Of Graphene Oxide Based TiO₂ Photocatalyst And Its Photocatalytic Performance For Gaseous Benzene

With the rapid development of social economy,the problem of air pollution is becoming more and more serious,which seriously affects human survival and health,but also limits the progress of economy and society.Therefore,it is an urgent need to find a new and effective way to improve people's living standards and quality of life and promote social sustainable development.In this paper,a series of new composite photocatalysts are prepared by using graphene oxide(GO)as the substrate material and TiO2 as the support.Benzene is a typical VOCs pollutant.Under different conditions,the photocatalytic performance of the composite photocatalyst under dynamic experimental conditions was studied.In this paper,a series of nano GO-TiO2 composite photocatalysts are prepared by using natural scale graphite as raw material,using butyl titanate and commercial titanium dioxide(P25)as titanium sources,respectively,and using hydrothermal method to load TiO2 on the graphene oxide(GO).The conditions are optimized to determine the optimal synthesis conditions of the composite photocatalyst,and the photocatalytic experiments are carried out with the composite photocatalyst.The effects of initial concentration,residence time,light intensity,amount of catalyst and service life of the catalyst on benzene degradation are investigated respectively.The composite photocatalyst is analyzed by TEM,XRD,SEM,FT-IR and BET.In this paper,the components of tail gas from benzene photocatalysis are analyzed and identified by GC-MS.The main conclusions are as follows:(1)SEM and TEM show that GO has a large plane and a very thin lamellar structure,and the increase of GO doping will have a greater impact on the morphology of composite photocatalyst,resulting in the aggregation of TiO2 in composite photocatalyst.XRD shows that the addition of GO will not change the crystal structure of TiO2,and the composite photocatalyst prepared with butyl titanate as titanium source will be calcined at temperature.When the calcination temperature is increased to 600?,the crystal structure changes to rutile phase,and GO is reduced to reduced graphene oxide in the process of hydrothermal preparation.FT-IR shows that the combination mode of GO and TiO2 is the combination of chemical bond,and the surface of composite photocatalyst is rich.BET shows that GO has a larger specific surface area and a larger specific surface area than pure TiO2(2)The pure UV light of 254nm has a certain degradation effect on benzene The empty tower experiment shows that the degradation rate of benzene decreases with the increase of initial concentration,and the UV light intensity and residence time have a great influence on the degradation effect of benzene.With the increase of UV light intensity,the degradation efficiency of benzene increases significantly.The longer the gas residence time in the reaction device,the better the degradation efficiency of benzene.When the carrier gas is air,the initial concentration of benzene is about 103mg/m3,and the control gas residence time is close to 50s.The main wavelength of the light source is 254nm UV sterilization lamp with 48W power.The maximum degradation rate of benzene is 52.64%after 4h of illumination(3)There is an adsorption catalysis synergy between TiO2 and GO.When the doping amount of GO is 1%,the degradation rate of benzene on the 1%GO-TiO2-550 composite photocatalyst prepared with butyl titanate as titanium source and calcination temperature at 550? is 59.66%.Compared with P25 as titanium source,the degradation rate of 1%GO-P25 is increased by 6.31%,which is 1.97 times of that of pure commercial P25(4)The best pretreatment method for catalyst immobilization is to dry the catalyst at 110?,and the best photocatalytic activity is to reduce the loss rate of the catalyst.The best 1%GO-TiO2-550 composite photocatalyst is prepared for photocatalysis experiment.The experiment shows that the initial concentration of benzene is about 103mg/m3,and the control gas residence time is close to 50s.The main wavelength of the light source is 254nm UV sterilization lamp with 48W power,and the air is empty.The average degradation rate of benzene is 84.96%in the first hour of illumination,which is 32.32%higher than that in the empty tower experiment(5)The tail gas components of benzene under composite photocatalyst mainly include:acetic acid,acetone,ethylenediyne,3,4-dimethyl-2-pentene,2-ethyl-1-ethylene,toluene,benzaldehyde,2-methyl-1,4-dioxane,dibutyl phthalate Compared with the tail gas of empty tower,the by-products of benzene are more than 3,4-dimethyl-2-pentene,2-methyl-1,4-dioxane and 2-ethyl-1-ethylene.The mineralization rate is 73.01%,which is 41.72%higher than that of empty tower experiment.