Adsorption Species Distribution and Multicomponent Adsorption Mechanism of SO2, NO, and CO2 on Commercial Adsorbents

Adsorption is a commonly used method for gas pollutant removal. The adsorption performances of four commercial adsorbents have been compared in this work through a fixed-bed reactor. The single gas adsorption results show that zeolite is more effective for SO2, NO, and CO2 removal among the four adsorbents. SO2, NO, and CO2 are mainly monolayer adsorbed on adsorbents. Physically adsorbed SO2 is the main adsorption species on 13X zeolite, 5A zeolite, and mesoporous alumina according to TPD-MS, while SO2 is more easily oxidized on activated carbon than the other adsorbents. NO can be oxidized more easily on zeolite than activated carbon. Only physically adsorbed CO2 is detected on these adsorbents. Multicomponent adsorption is investigated on 13X zeolite and activated carbon. For gas adsorption on 13X zeolite, the inhibitive effect of NO on SO2 is 26.3% higher than that of CO2 on SO2, indicating that NO plays a dominant role in SO2 adsorption. Physically adsorbed NO is the only NO adsorption species on 13X when SO2 exists, showing NO oxidation on 13X is greatly inhibited by SO2. For gas adsorption on activated carbon, chemically adsorbed SO2 increases largely after NO is put in, showing that the promotive effect of NO on SO2 is mainly for the chemically adsorbed SO2. In the presence of SO2, chemically adsorbed NO almost disappeared, which indicates that SO2 mainly dominates chemically adsorbed NO on activated carbon. The effects of adsorbent performance on multicomponent gas adsorption are reflected by the gas adsorption mechanism. These findings provide considerable specific information for industrial flue gas purification.