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

Guo, Yangyang, Li, Yuran, Zhu, Tingyu, Ye, Meng
Energy & Fuels 2013 v.27 no.1 pp. 360-366
X-ray photoelectron spectroscopy, activated carbon, adsorption, desorption, ion exchange chromatography, nitric oxide, sulfur dioxide, temperature
The effects of various SO₂ and NO concentrations on the adsorption capacity of activated carbon were measured experimentally for sequential and simultaneous adsorption of SO₂ and NO in a fixed bed using an area integral calculation method. The results show that higher NO concentrations increase SO₂ adsorption, especially for CNO > 200 ppm; however, higher SO₂ concentrations restrict NO adsorption with little NO adsorbed for CSO₂ > 700 ppm. The NO adsorption capacity decreases as the SO₂/NO ratio increases, while the total adsorption capacity for SO₂ and NO has a peak at SO₂/NO = 1.7. The product analysis by XPS supports that NO promotes SO₂ chemisorption, SO₂ occupies both C–O and CO groups, but NO occupies the C–O group. The TPD-MS measurement shows that most of the SO₂ is chemisorbed, and the ion chromatography measurement indicates that 66.0% of the total adsorbed SO₂ is oxidized to SO₃. SO₂ 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.