Stability of Amine-Based Hollow Fiber CO₂ Adsorbents in the Presence of NO and SO₂


Comparative studies of the cyclic stability of primary, secondary, and tertiary amine-grafted silica/polymer composite fiber adsorbents upon exposure to simulated flue gas are reported. A simulated dry flue gas mixture with 200 ppm NO does not cause degradation of the amine grafted fiber adsorbents and all fibers retain their CO₂ capacity in the presence of NO. In contrast, upon exposure to dry flue gas in the presence of 200 ppm SO₂ at 35°C, the primary amine containing adsorbent, CA-S-APS, shows a CO₂ capacity reduction of 55% over 120 cyclic adsorption-desorption runs. As the initial SO₂ induced degradation occurs in this adsorbent, the amine sites first irreversibly adsorb SO₂ and then begin to gradually adsorb SO₂ reversibly, as evidenced from a quantitative comparison of the amount of adsorbed SO₂ to the amount of desorbed SO₂. The secondary amine containing adsorbent, CA-S-MAPS, exhibits an improved stability and approximately 25% CO₂ capacity loss is observed during cycling in the presence of SO2. Therefore, the secondary amine based CA-S-MAPS adsorbent demonstrates some degree of tolerance to SO2 in comparison to the CA-S-APS sample. Under humid conditions, SO₂ imposes significant detrimental impacts on the two adsorbents, as a result of increased SO₂ adsorption capacities in the presence of moisture. Although the CO₂ uptake is nearly zero in the tertiary amine adsorbent, CA-S-DMAPS, the SO₂ capacity of this adsorbent reaches 0.43 mmol/g under humid conditions and this material has the highest SO₂/N ratio of the fiber adsorbents studied. More importantly, this CA-S-DMAPS sample demonstrates reversible SO₂ adsorption, as indicated from the SO₂ cyclic adsorption experiments. The tertiary amine based fiber adsorbents have good potential for flue gas desulfurization, with advantageous characteristics of high SO₂/N ratio, excellent reversibility, low CO₂ adsorption and relatively low regeneration temperature.


Chemical and Biochemical Engineering


The authors acknowledge the DOE-NETL under contract DE-FE0007804 for financial support.

Keywords and Phrases

Adsorption; Amines; Carbon; Carbon Dioxide; Desorption; Fibers; Flue Gases; Flues; Gas Adsorption; Grafting (Chemical); Ionization of Gases; Optical Projectors; Stability; Sulfur Dioxide; Adsorption Capacities; Adsorption Desorption; Adsorption Experiment; Cyclic Stability; Flue Gas Desulfurization; Hollow Fiber; Quantitative Comparison; Regeneration Temperature; Adsorbents; Carbon Dioxide NO

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Article - Journal

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© 2015 Elsevier, All rights reserved.

Publication Date

01 Nov 2015