Adsorption performance of CMK-3 and C-FDU-15 in NO removal at low temperature

CMK-3 and C-FDU-15 samples were synthesized using hard-templating and evaporation-induced self-assembly (EISA) methods, respectively. The pore structures of CMK-3 and C-FDU-15 as well as commercial activated carbon were characterized by means of X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and N₂ adsorption-desorption. Adsorption of NO was investigated by means of thermogravimetric analysis, temperature-programmed desorption of NO + O₂, and in situ diffuse reflectance Fourier transform infrared spectroscopy. The results show that the CMK-3 and C-FDU-15 materials possessed ordered and uniform structures. The co-adsorption capacity of NO and O₂ decreased in the sequence CMK-3 (88.6 mg/g) > C-FDU-15 (71.7 mg/g) > AC (25.3 mg/g). There were two main adsorption species on CMK-3 and C-FDU-15: nitrite and nitrate. Nitrite is converted to nitrate easily. However, the adsorption species were more complex on AC, with nitrite being the main species. Moreover, CMK-3 and C-FDU-15 exhibit excellent regeneration efficiency compared with AC. The excellent NO adsorption performance of CMK-3 and C-FDU-15 was associated with their ordered mesoporous structures and high surface areas. The research provides more options for NO adsorption in the future.