Role of Alumina Basicity in CO2 Uptake in 3‐Aminopropylsilyl‐Grafted Alumina Adsorbents. Issue 10 (26th April 2017)

• Record Type: Journal Article
• Authors: Potter, Matthew E.; Cho, Kyeong Min; Lee, Jason J.; Jones, Christopher W.
• Is Part Of: ChemSusChem. Volume 10:Issue 10(2017)
• Page Start: 2192
• Page End: 2201
• Publication Date: 2017-04-26
• Subjects: adsorption -- amino silicates -- calorimetry -- carbon storage -- ir spectroscopy; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201700115
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Oxide‐supported amine materials are widely known to be effective CO2 sorbents 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 CO2 sorption 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 N2 physisorption analysis, in situ FTIR spectroscopy, and adsorption microcalorimetry. Abstract : Choosing the right support : The behavior of amine‐modified solid CO2 sorbents is dictated by the relationship between the amine sites and the solid oxide support. To fully optimize such a sorbent for industrial purposes, this relationship must be understood. To this end we present a detailed study combining in situ infrared spectroscopy with microcalorimetry to probe the relationship between primary amines and mesoporous alumina supports.