Studying On Catalytic Combustion Elimination Of Maldehydes VOCs

In recent years, VOCs pollution has been more and more serious. Formaldehyde exists widely in people's household living, car exhaust and industrial waste gas, which does great harm to people's living health. All countries strictly control the limited concentration of formaldehyde in the living house, therefore, how to eliminating the formaldehyde in the air attracts more and more concern. Catalytic combustion has been one of the best methods of eliminating VOCs, which has some advantages such as low ignition temperature, wide using scale, high treatment efficiency and no second pollution. Catalysts for eliminating VOCs include supported noble metals and metallic oxides. Metallic oxides are less active than noble metals at low temperature, however, they have low price and rouse people's interest.Single component MnO2/SBA-15 catalysts with 5wt%-40wt% Mn content were prepared. It turned out that, when Mn content is 20wt%, catalysts were the activest and formaldehyde was completely transformed at 195℃. Catalysts were characterized by XRD, BET and HRTEM. It turned out that, mesopore structure still existed; diffraction peaks of MnO2 were found and diffraction peaks were enhanced with Mn content increasing.Double component N-MnO2/SBA-15 (N=Co, Cu, La, Ce, Al) catalysts were prepared. Mn content was 20wt% and N content was 10wt%. It turned out that, addiction of Al increased the catalytic activity best and formaldehyde was completely transformed at 140℃.Double component Al-MnO2/SBA-15 catalysts were prepared. Mn conte-nt was 20wt% and Al content ranged from 0.5wt% to 8wt%. It turned out that, when Al content is 5wt%, catalysts had best activity and formaldehyde was completely transformed at 120℃. Catalysts were characterized by XRD, BET, TPR and HRTEM. It turned out that, mesopore structure still existed; diffracti-on peaks of MnO2 were found and diffraction peaks were weakend with Al content increasing; diffraction peaks of Al phase were not found; as Al content were increased, the high temperature reductive peaks shifted to higher temper-ature and the low tempereature reductive peaks shifted to lower temperature.Single component MnO2/SBA-15/cordierite catalysts and double component Al-MnO2/SBA-15/cordierite catalysts were prepared. In MnO2/SBA-15/cordierite catalysts, when Mn content was 20wt% and 30wt%, catalysts had best activity and formaldehyde was completely transformed at 155℃. In Al-MnO2/SBA-15/cordierite catalysts, when Mn content was 20wt% and Al content was 5wt%, catalyst had best activity and formaldehyde was completely transformed at 130℃.