Preparation Of Honeycomb Cu-Mn-Ce/Cordierite Catalyst And Its Application In Microwave-assisted Catalytic Oxidation Of Gaseous Toluene

With the increasing public awareness of air quality,more and more people pay attention to volatile organic compounds?VOCs?pollution.VOCs are not only harmful to human health,but also the precursors of secondary organic aerosols and PM_2.5,which cause secondary pollution to the environment.Toluene as one of typical VOCs,is widely used in automotive spraying,furniture manufacturing and printing industries.Catalytic oxidation is an effective technology for the treatment of VOCs pollution.The development of microwave-assisted catalytic oxidation of toluene can provide a new way for the degradation of VOCs,and has guiding significance for the treatment of VOCs and improvement of air quality.In the experiment,the honeycomb carrier with large specific surface area,strong shock resistance,high thermal stability,high porosity and reduced pressure was used to prepare Cu-Mn-Ce/honeycomb catalyst that owing strong microwaving-absorbing capalysts by impregnation method.The microwave-absorbing ability and catalytic activity of the catalysts,which were made by incipient-wetness impregnation method and excessive impregnation method respectively,were investigated.The optimal reaction temperature of the catalyst.was tested.The catalyst was optimized from both the catalyst carrier and active component loading to selecte the catalyst with high catalytic activity.Moreover,the mineralization of toluene and catalyst's stability were investigated in experiment.Finally,both the honeycomb carrier and catalysts were characterized by SEM,BET,XRD,H₂-TPR and XRF,separately.The results showed that the active component loading and catalytic activity of the catalyst,which was prepared by incipient-wetness impregnation method were higher than excessive impregnation method,and the former had the best catalytic effect on toluene oxidation at 200°C of reaction temperature.Cordierite-supported catalyst's catalytic activity was better than SiC-supported catalyst,and the recombination of titanium dioxide coating did not enhance the activity of the catalyst.When cordierite:Cu:Mn:Ce was 120:3:3:1?mass ratio?,the catalytic activity was the highest and the degradation rate and mineralization rate of the catalyst to toluene were 98%and70%,respectively,and it still has more than 90%degradation of toluene in the 1980min stability test.The experiments of the intake conditions showed that the change of the intake air amount had a greater effect on the ability of the catalyst to degrade toluene than the intake air concentration.The characteristics of the catalysts indicated that the type and content of the active component on the surface of cordierite-supported catalysts were higher than those of SiC-supported catalysts.The active component and the titanium dioxide coating were both beneficial to increase the specific surface area of the catalyst,which was beneficial to increase adsorption performance of the catalyst.This paper has carried out the useful exploration on the preparation of highly effective catalyst for VOCs oxidation under microwave radiation,and honeycomb Cu-Mn-Ce/cordierite catalyst exhibited high removal and mineralization efficiencies in the process of microwave assisted catalytic oxidation of gaseous toluene.The research work provided theoretical base on the real application of this new technology of microwave assisted catalytic oxidation.