(484d) Enhanced Performance of Polymeric Amines Supported On Heteroatom-Incorporated Silica in CO2 Adsorption/Desorption
AIChE Annual Meeting
2013 AIChE Annual Meeting
Environmental Applications of Adsorption II: Gas Phase
Wednesday, November 6, 2013 - 1:30pm to 1:50pm
Silica-aminopolymer composites are promising materials that can be used to adsorb CO2 from dilute gases, with the most commonly studied compositions being simulated flue gas from power plants (ca. 5-15% CO2) and ambient air (ca. 400 ppm CO2). The CO2 adsorption characteristics of prototypical, class 1  poly(ethyleneimine)-silica composite adsorbents are shown here to be significantly enhanced by altering the acid/base properties of the silica support via heteroatom incorporation into the silica matrix.  To demonstrate this, a series of poly(ethyleneimine)-impregnated mesoporous silica SBA-15 materials containing heteroatoms (Al, Ti, Zr, and Ce) in the silica matrix are prepared and characterized in adsorption experiments under conditions simulating flue gas (10% CO2 in Ar) and ambient air (400 ppm CO2 in Ar). The structure of the composite adsorbents, including local information concerning the state of the incorporated heteroatoms and the overall surface properties of the silicate supports, are investigated to develop a relationship between the adsorbent structure and CO2 adsorption/desorption performance. The CO2 adsorption/desorption kinetics are assessed by thermogravimetric analysis and in-situ FT-IR measurements. These combined results, coupled with data on adsorbent regenerability, demonstrate a stabilizing effect of the heteroatoms on the poly(ethyleneimine) contained within the support mesopores, enhancing adsorbent capacity, adsorption kinetics, regenerability, and stability of the supported aminopolymers over continued cycling.  It is suggested that the CO2 adsorption performance of silica-aminopolymer composites may be further enhanced in future work by more precisely tuning the acid/base properties of the support, an approach that has not yet been widely exploited in the literature.
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