Influence of textures, oxygen-containing functional groups and metal species on SO2 and NO removal over Ce-Mn/NAC

A series of Ce and Mn bimetal modified activated carbon were prepared by excessive impregnation method. The removal of SO2 or NO was carried out at a fixed bed reactor under a simulated flue gas. The results showed that Ce(1)-Mn/NAC exhibits excellent SO2 removal capacity at 80 °C with breakthrough sulfur capacity of 113 mg/g, and Ce(7)-Mn/NAC displays a good NO removal capacity and maintains 100% removal efficiency in the range of 130-220 °C. The specific surface area and pore volume decline first and then increase with the increase of Ce loadings, and the pore sizes of samples center at 0.4-4 nm. CO and OCO groups are favorable for SO2 oxidation, and CO can promote the oxidation of SO2 and NO. The OH groups can promote the adsorption and oxidation of SO2 and NO, but the ways that they acted are different. Mn2O3, Mn3O4, Ce2O3 and CeO2 are observed in fresh samples, but MnO2 and Ce2(SO4)3 are detected and Ce2O3 disappears after desulfurization. MnO2 appears after denitration when Ce loading amount is small, but it disappears gradually with the increase of Ce loadings. CeO2 gradually decreases while Ce2O3 is increasing after denitration, indicating that CeO2 can convert into Ce2O3 in NO removal process.