Catalyst carriers optimization and characteristics of microwave catalytic combustion of toluene
ZHANG Tingting1,, BO Longli1,2,3,,, NING Ke1, LIU Shuang1 1.School of Environmental and Municipal Engineering, Xi′an University of Architecture and Technology, Xi′an 710055, China 2.Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi′an 710055, China 3.Key Laboratory of Environmental Engineering of Shaanxi Province, Xi′an 710055, China
Abstract:The selection of catalyst carriers is critical to improve the activity and stability of catalyst. In this study, three carriers of honeycomb cordierite, mullite, and carbon fiber zirconium chromium corundum were taken as research targets to prepare Cu-Mn-Ce supported catalysts by impregnation method. The carriers and catalysts were evaluated completely based on relative characterizations and microwave catalytic combustion of toluene in order to look for the carrier with good performance in the application of microwave catalytic combustion of volatile organic compounds (VOCs). The study showed that Cu-Mn-Ce/carbon fiber zirconium chromium corundum had the best catalytic activity and stability, then Cu-Mn-Ce/mullite followed and Cu-Mn-Ce/cordierite was the poorest one. At microwave power of 50 W, 100 mm catalyst height, airflow of 0.12 m3·h?1 and initial concentration of 1 000 mg·m?3, the degradation efficiencies of toluene by three catalysts that prepared under optimal parameters were 98%, 98% and 90%, respectively. The optimal preparation parameters of Cu-Mn-Ce/carbon fiber zirconium chromium corundum were following: active components loading amounts of 4.50%, calcination temperature of 450 ℃ and calcination time of 4~5 h, and its excellent catalytic capacity was 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 the mesopore structure of the catalyst, the reduction of the specific surface area and pore volume could lead to the agglomeration of active particles on the surface of the catalyst, but it was conducive to new crystal yield of active components and the degradation of the pollutants. Loaded amounts of active components and calcination time had obvious effect on catalytic activity of Cu-Mn-Ce/cordierite, this catalyst had the poorest activity for toluene degradation, while its lowest preparation cost could imply a potential of market application. The study on the optimal preparation conditions of three catalysts provides reference for the preparation of high-performance catalyst with strong microwave-absorbing capacity in the future. Key words:microwave catalytic combustion/ toluene/ carrier selection/ catalytic activity/ characterization.
图1实验装置流程图 Figure1.Flow diagram of experimental apparatus
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1.School of Environmental and Municipal Engineering, Xi′an University of Architecture and Technology, Xi′an 710055, China 2.Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi′an 710055, China 3.Key Laboratory of Environmental Engineering of Shaanxi Province, Xi′an 710055, China Received Date: 2020-03-09 Accepted Date: 2020-04-21 Available Online: 2020-12-08 Keywords:microwave catalytic combustion/ toluene/ carrier selection/ catalytic activity/ characterization Abstract:The selection of catalyst carriers is critical to improve the activity and stability of catalyst. In this study, three carriers of honeycomb cordierite, mullite, and carbon fiber zirconium chromium corundum were taken as research targets to prepare Cu-Mn-Ce supported catalysts by impregnation method. The carriers and catalysts were evaluated completely based on relative characterizations and microwave catalytic combustion of toluene in order to look for the carrier with good performance in the application of microwave catalytic combustion of volatile organic compounds (VOCs). The study showed that Cu-Mn-Ce/carbon fiber zirconium chromium corundum had the best catalytic activity and stability, then Cu-Mn-Ce/mullite followed and Cu-Mn-Ce/cordierite was the poorest one. At microwave power of 50 W, 100 mm catalyst height, airflow of 0.12 m3·h?1 and initial concentration of 1 000 mg·m?3, the degradation efficiencies of toluene by three catalysts that prepared under optimal parameters were 98%, 98% and 90%, respectively. The optimal preparation parameters of Cu-Mn-Ce/carbon fiber zirconium chromium corundum were following: active components loading amounts of 4.50%, calcination temperature of 450 ℃ and calcination time of 4~5 h, and its excellent catalytic capacity was 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 the mesopore structure of the catalyst, the reduction of the specific surface area and pore volume could lead to the agglomeration of active particles on the surface of the catalyst, but it was conducive to new crystal yield of active components and the degradation of the pollutants. Loaded amounts of active components and calcination time had obvious effect on catalytic activity of Cu-Mn-Ce/cordierite, this catalyst had the poorest activity for toluene degradation, while its lowest preparation cost could imply a potential of market application. The study on the optimal preparation conditions of three catalysts provides reference for the preparation of high-performance catalyst with strong microwave-absorbing capacity in the future.