title: Role of Alumina Basicity in CO2Uptake in 3-Aminopropylsilyl-Grafted Alumina Adsorbents.
abstract: Oxide-supported amine materials are widely known to be effective CO2sorbents under simulated flue-gas and direct-air-capture conditions. Most work has focused on amine species loaded onto porous silica supports, though potential stability advantages may be offered through the use of porous alumina supports. Unlike silica materials, which are comparably inert, porous alumina materials can be tuned to have substantial acidity and/or basicity. Owing to their amphoteric nature, alumina supports play a more active role in CO2sorption than silica supports, potentially directly participating in the adsorption process. In this work, primary amines associated with 3-aminopropyltriethoxysilane are grafted onto two different mesoporous alumina materials having different levels of basicity. Adsorbent materials with different amine loadings are prepared, and the CO2-adsorption behavior of similar amines on the two alumina supports is demonstrated to be different. At low amine loadings, the inherent properties of the support surface play a significant role, whereas at high amine loadings, when the alumina surface is effectively blocked, the sorbents prepared on the two supports behave similarly. At high amine loadings, amine-CO2-amine interactions are shown to dominate, leading to adsorbed species that appear similar to the species formed over silica-supported amine materials. The sorbent properties are comprehensively characterized using N2physisorption analysis, in situ FTIR spectroscopy, and adsorption microcalorimetry.
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA, 30332, USA.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Potter
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA, 30332, USA.|Department of Chemical and Biomolecular Engineering (BK-21 plus), Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Republic of Korea.
authors.forename: Kyeong Min
authors.initials: KM
authors.lastname: Cho
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA, 30332, USA.
authors.forename: Jason J
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA, 30332, USA.
authors.forename: Christopher W
authors.identifier: 0000-0003-3255-5791
authors.initials: CW
authors.lastname: Jones
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D002151:Calorimetry; D002245:Carbon Dioxide / Q000737:chemistry*; D033362:Powder Diffraction; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002245:Carbon Dioxide; D012822:Silicon Dioxide; D000537:Aluminum Oxide
keywords: adsorption; amino silicates; calorimetry; carbon storage; ir spectroscopy