Lemus, JesúsMoya, CristianMoreno, DanielAlonso Morales, NoeliaPalomar Herrero, José FranciscoSantiago Lorenzo, Rubén2024-05-202024-05-202018-09-21http://doi.org/10.1021/acssuschemeng.8b02797https://hdl.handle.net/20.500.14468/12386The performance of three amino-acid-based ionic liquids (aa-ILs) has been evaluated in CO2 capture by means of gravimetric measurements. The tested aa-ILs were 1-butyl-3- methylimidazolium prolinate, [Bmim][PRO]; 1-butyl-3-methylimidazolium methioninate, [Bmim][MET]; and 1-butyl-3-methylimidazolium glycinate, [Bmim][GLY]. First, the CO2 chemical absorption process was analyzed by in situ Fourier transform infrared spectroscopy−attenuated total reflection (FTIR-ATR), following the characteristic vibrational signals of the reactants and products, and comparing them with theoretical measurements obtained by quantum chemical calculations. This study let us confirm a mechanism of CO2 chemical absorption on amino-acid-based ILs. Then, gravimetric experiments were carried out to characterize the CO2 capture by aa-ILs. It was found that CO2 absorption quantification of these ILs was rather slow, because of their high viscosities, so alternative methodologies had to be employed to use them as absorbents in CO2 capture. In this sense, aa-ILs were encapsulated in porous carbon capsules (aa-ENIL), since it has been previously reported as material that defeats the kinetic limitations and preserves the favorable CO2 capture capacity of the neat ILs, promoting efficient chemical absorption. These aa-ENIL materials permit evaluation of CO2 capture at equilibrium and experimentally characterize the thermodynamics absorption phenomena, in terms of reaction enthalpy and the contribution of physical (H) and chemical (Keq) CO2 absorption for each IL. ENIL materials allow a fast CO2 capture with high sorption capacity and easy regeneration due to the favorable thermodynamics and kinetics of the process.eninfo:eu-repo/semantics/openAccessjournal articleChemical CO2 captureAmino-acid-basedIonic liquidsaa-ENIL