Enhancing the low concentration CO2-capture abilities of aminium ionic liquids through blending with acetate ionic liquids

The efficient capture of low-concentration CO2 is essential for achieving carbon neutrality and recycling. This study explored aminium and acetate ionic liquid (IL) mixtures for enhanced CO2 capture. The physical properties, nuclear magnetic resonance spectra, and CO2 solubilities of the mixtures of...

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Bibliographic Details
Main Authors: Yu Nagai Kanasaki, Yuki Kohno, Takashi Makino
Format: Article
Language:English
Published: Elsevier 2025-11-01
Series:Journal of CO2 Utilization
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Online Access:http://www.sciencedirect.com/science/article/pii/S221298202500174X
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Summary:The efficient capture of low-concentration CO2 is essential for achieving carbon neutrality and recycling. This study explored aminium and acetate ionic liquid (IL) mixtures for enhanced CO2 capture. The physical properties, nuclear magnetic resonance spectra, and CO2 solubilities of the mixtures of N-2-hydroxyethyl-aminoethylaminium bis(trifluoromethanesulfonyl)imide (1·[Tf2N]) and 1-ethyl-3-methylimidazolium acetate ([C2mim][AcO]) were compared with those of the corresponding [C2mim][Tf2N] mixtures. It was found that the mixtures were less dense and viscous than the pure aminium IL, enabling faster absorption/desorption kinetics and lowering energy consumption. In addition, mixtures containing 10 and 30 mol% 1·[Tf2N] absorbed greater amounts of CO2 than the pure ILs at CO2 partial pressures of up to 10 kPa, with a lower absorption heat than pure 1·[Tf2N]. This was attributed to the formation of nonionic components via proton recombination, along with the suppression of ammonium formation by proton sharing between the CO2 adduct and the [AcO]− anions. Blending [C2mim][AcO] with other aminium ILs further enhanced the CO2 absorption capability at low partial pressures, offering a higher CO2 solubility and a lower enthalpy compared to the 1·[Tf2N] mixture. Overall, the results indicated that mixing aminium ILs with [C2mim][AcO] enhances low-concentration CO2 capture and is applicable to various aminium ILs, providing an effective alternative to chemical modification for the development of CO2 separation materials.
ISSN:2212-9839