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

Luo, Lei, Guo, Yangyang, Zhu, Tingyu, Zheng, Yang
Energy & Fuels 2017 v.31 no.10 pp. 11026-11033
activated carbon, adsorbents, adsorption, aluminum oxide, biogeography, carbon dioxide, flue gas, fuels, nitric oxide, oxidation, pollutants, porous media, sulfur dioxide, zeolites
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.