Selection Of Honeycomb Catalyst Carriers And Microwave Catalytic Combustion Of Gaseous Toluene

The emission of volatile organic compounds?VOCs?is harmful to human health and VOCs are key precursors for the formation of photochemical smog,PM_2.5.5 and ozone.Therefore,the treatment of VOCs can effectively curb their harm to human health and pollution to the atmosphere.Catalytic combustion is a simple,efficient,and convenient treatment technology,which can effectively eliminate VOCs by using catalysts to accelerate oxidation of VOCs.Microwave heating has the advantages of selectivity,fast start-up and uniform heating.The combination of catalytic combustion and microwave heating for the treatment of VOCs has broad market prospects.As one typical VOCs,toluene is selected as the target pollutant.The research in microwave catalytic combustion of gaseous toluene can provide a new way for the elimination of VOCs and has practical guiding significance for the treatment of VOCs pollution.The selection of catalyst carriers is critical to improve catalyst activity and stability.In this paper,three carriers of honeycomb cordierite,mullite,and carbon fiber zirconium chromium corundum have been chosen as the research targets to prepare Cu-Mn-Ce supported catalysts by an impregnation method.The carriers and catalysts loaded have been evaluated completely based on relative characterizations and microwave catalytic combustion of toluene to look for much better carrier with high quality in the application of microwave catalytic combustion of VOCs.Based on the experimental research,the following research conclusions are listed.?1?Cu-Mn-Ce/carbon fiber zirconium chromium corundum had the best catalytic activity and stability and followed orderly by Cu-Mn-Ce/mullite and Cu-Mn-Ce/cordierite.Under conditions of microwave power 50W,catalyst bed height100mm,airflow 0.12m³/h and initial concentration 1000mg/m³,the degradation efficiencies of toluene by three catalysts that prepared under optimal parameters were98%?35min?,98%?45min?and 90%?35min?,respectively.?2?The optimal preparation parameters of Cu-Mn-Ce/carbon fiber zirconium chromium corundum were 4.5wt%loaded amounts of active components,450?of calcination temperature and 4?5h of calcination time,and its excellent catalytic capacity is due to good microwave-absorbing property,some adsorption capacity,most spinel active components,synergistic effect of carbon fiber and super thermal resistance ability of the carrier.High temperature had a great effect on mesopore structure of the catalyst to reduce the specific surface area and pore volume obviously and lead to apparent agglomeration of active particles on the surface of the catalyst simultaneously.However,it was beneficial to form new crystal of active components that enhancing the degradation of the pollutants.Loaded amounts of active components and calcination time had obvious effect on the catalytic activity of Cu-Mn-Ce/cordierite,which had the worst activity for toluene degradation and the lowest price in preparation that resulting in a potential of market application.The research work on the optimal preparation conditions of three catalysts provides a theoretical basis on the preparation of high-performance catalyst with strong microwave-absorbing capacity in the future.