Research On The Dederadation Of Typical BETX Under Vacuum Ultraviolet Irradiation

Vacuum ultraviolet is an emerging process for the treatment of volatile organic compounds.However,some problems need to be solved in engineering applications: 1.The utilization rate of ultraviolet photon emitted by ultraviolet light is low and the efficiency of vacuum ultraviolet degradation of volatile organic compounds is poor.2.Furthermore,in different working conditions,the degradation of volatile organic compounds varies extremely under vacuum ultraviolet radiation.3.The mechanism of degradation of volatile organic compounds and the contribution rate of degradation of different degradation pathways need further study.4.Optimizing unreasonable UV equipment design is necessary.In order to explore the above several issues,the research content of this paper is as follows:1.Select the typical BETX(toluene)as the target pollutant to study,and test the degradation efficiency of vacuum ultraviolet toluene under different working conditions.The main parameters affecting toluene in the vacuum UV process are the initial concentration of toluene,the gas phase humidity,the residence time of the gas in the equipment,the UV lamp power,and the gaseous medium.The experimental results show that the higher the initial concentration of toluene,the lower the degradation efficiency of toluene,the degradation amount of toluene is gradually increased conversely.The experimental results showed that the higher initial concentration of toluene,the lower the degradation efficiency of toluene,but the degradation of toluene is gradually increased,and the amount of toluene degradation is related to the lamp power.When the UV lamp power is constant,the higher the relative humidity of the gas,the higher the degradation efficiency of toluene.The degradation rate of toluene increases with the increase of the residence time of the gas in the vacuum ultraviolet device.In a certain time range,the photodegradation of toluene satisfies the first-order kinetic equation;The increase of UV lamp power is beneficial to increase the degradation rate of toluene.The toluene has obviously increase in the efficiency of vacuum-degrading toluene in medium with oxygen and water vapor.2.The contribution rate of different pathways to the degradation efficiency of toluene under vacuum ultraviolet conditions was investigated under different medium conditions.The experimental results showed that the contribution of hydroxyl radicals to toluene degradation was 56.77%,the contribution of oxygen radicals to toluene degradation of toluene was 15.63%,and the efficiency of direct photolysis of toluene was 15.37%.The intermediate products of toluene under different conditions were tested by gas chromatography-mass spectrometry.The degradation process and mechanism of toluene were analyzed.what’s more,the sources of oxide species(reactive oxygen species,hydroxyl radicals)during the degradation of toluene were analyzed.3.The vacuum UV equipment plays a crucial role in the utilization of vacuum UV lamps and the degradation efficiency of organic waste gases.In this study,the internal flow field of different vacuum ultraviolet devices was simulated by fluent.The vacuum velocity of the vacuum ultraviolet lamp is simulated in a neatly arranged and misaligned arrangement,and the tapered taper is 30°,45°,60°,90°,and the vacuum ultraviolet light is arranged in a cross-flow arrangement and a downstream arrangement.Degree changes and comparisons.Finally,the cylindrical vacuum ultraviolet equipment was designed by simulation optimization,which has certain guiding significance for engineering application.