Effects of Concentration and Adsorption Product on the Adsorption of SO2 and NO on Activated Carbon

The effects of various SO 2 and NO concentrations on the adsorption capacity of activated carbon were measured experimentally for sequential and simultaneous adsorption of SO 2 and NO in a fixed bed using an area integral calculation method. The results show that higher NO concentrations increase SO 2 adsorption, especially for C NO > 200 ppm; however, higher SO 2 concentrations restrict NO adsorption with little NO adsorbed for C SO 2 > 700 ppm. The NO adsorption capacity decreases as the SO 2 /NO ratio increases, while the total adsorption capacity for SO 2 and NO has a peak at SO 2 /NO = 1.7. The product analysis by XPS supports that NO promotes SO 2 chemisorption, SO 2 occupies both C–O and C═O groups, but NO occupies the C–O group. The TPD-MS measurement shows that most of the SO 2 is chemisorbed, and the ion chromatography measurement indicates that 66.0% of the total adsorbed SO 2 is oxidized to SO 3 . SO 2 replaces the physisorbed NO, which is 94.3% of the total adsorbed NO, but cannot desorb the chemisorbed NO. TPD experiments show two NO desorption peaks at 200 and 280 °C, and almost all the NO desorbed as the temperature increases to 500 °C, with the chemisorbed NO being 5.6% of the total adsorbed NO.