Abstract:
NO and dichloromethane trigger the generation of a series of atmospheric pollutants such as O
3 and PM
2.5, which has attracted extensive attention worldwide. A series of Cu and Ce modified V-W/Ti catalysts were prepared by a multi-step impregnation method and applied to the synergistic removal of NO and dichloromethane in the temperature range of 125–325 ℃. The synergistic removal of NO and dichloromethane by these catalysts under different operating conditions was measured. The physical and chemical properties of the catalysts were analyzed by characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and ammonia programmed temperature-raising desorption (NH
3−TPD). The organic gases in the tail gas were analyzed by gas chromatography-mass spectrometry (GC−MS). The results showed that the loading of Cu and Ce significantly improved the performance of the catalysts and broadened the activity temperature range of the catalysts. The optimum loading ratio of Cu was 5%, and the catalysts achieved up to 90.4% NO removal when the reaction temperature was 225 ℃. The maximum dichloromethane removal was 96.0% at 250 ℃. The results also showed that the catalysts were suitable to produce dichloromethane at a high temperature. The modified V-W/Ti catalysts have more pore structure, larger specific surface area, and better redox capacity, and the resistance to sulfur and chlorine was greatly improved. The NO and dichloromethane removal efficiencies were only reduced by 7.8% and 6.4%, respectively, under the HCl atmosphere. In the presence of SO
2, the removal efficiency of dichloromethane could still reach more than 80.0%, and the increase in the initial concentration of NO also had a significant effect on the removal performance of dichloromethane, with a maximum removal rate of 97.5% at an initial concentration of NO of 600×10
–6, which demonstrated the synergistic effect of the V-W/Ti catalysts in the removal of these two pollutants.