Silica/polyethyleneimine composite adsorbent S-PEI for CO2 capture by vacuum swing adsorption (VSA)

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SBA15 type mesoporous silica was combined with a pore volume equivalent of branched polyethyleneimine PEI (MW 1200) to prepare a high capacity adsorbent S-PEI for the selective capture of CO2 from post combustion flue gas via pressure / vacuum swing adsorption (VSA). The adsorbent was characterized by helium pycnometry, N2 adsorption / desorption at 77 K, powder X-ray diffraction XRD and thermogravimetric analysis. The potential of S-PEI for CO2 capture via VSA was assessed by both CO2 partial pressure swing adsorption (PPSA) studies via combined thermogravimetric analysis (TGA) / differential thermal analysis (DTA), and by CO2 pressure / vacuum swing adsorption (VSA) studies via a custom bench gas sorption analyzer. The CO2 sorption capacities determined by partial pressure swings were consistent with those determined by pressure / vacuum swings as expected by the Henry gas law and therefore demonstrate the validity of PPSA to estimate VSA process working capacities. S-PEI was found to exhibit greater working CO2 capacity than zeolite 13X at 105 °C under key process conditions (0.05 - 0.15 atm CO2) from either anhydrous or humidified (̃1 % H2O) process gas. The amine adsorbent was also found to exhibit a higher Hads(CO2) (70-90 kJ.mol-1 than zeolite 13X (30-40 kJ.mol-1) as was expected for a chemisorption process. Zeolite 13X however was found to exhibit faster sorption kinetics under anhydrous process conditions consistent with its lower Hads(CO 2). Pelletized S-PEI exhibited the same good sorption kinetics as the powder, however with slightly reduced CO2 working capacity, 2.5 wt% at 105 °C, and minimal void volume, equivalent to 29.3 g of CO2 per L of sorbent bed. S-PEI was thus found to be attractive for CO2 capture from post combustion flue gas via VSA.

Original languageEnglish
Title of host publicationRecent Advances in Post-Combustion CO2 Capture Chemistry
EditorsMoetaz I Attalla
Place of PublicationWashington DC USA
PublisherAmerican Chemical Society
Number of pages29
ISBN (Print)9780841226210
Publication statusPublished - 2012
EventSymposium at the International Chemical Congress of Pacific Basin Societies (Pacifichem) 2010 - Hawaii Convention Center, Honolulu, United States of America
Duration: 15 Dec 201020 Dec 2010
Conference number: 6th

Publication series

NameACS Symposium Series
ISSN (Print)00976156
ISSN (Electronic)19475918


ConferenceSymposium at the International Chemical Congress of Pacific Basin Societies (Pacifichem) 2010
Abbreviated titlePacifichem 2010
CountryUnited States of America
Internet address

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