Evaluation of Capability of Some Amino Acid-based Poly (Ionic Liquid)s as Biocompatible Agent for Co2 Absorption

Abstract In this study, seven amino acid-based poly(ionic liquid)s (AAPILs) such as poly(1-butyl-3-vinylimidazolium glycinate), P[VBIm][Gly], poly (1-butyl-3-vinylimidazolium alaninate), P[VBIm][Ala], poly(1-butyl-3-vinylimidazolium valinate), P[VBIm][Val], poly(1-butyl-3-vinylimidazolium prolinate) P[VBIm][Pro], poly(1-butyl-3-vinylimidazolium hisdinate), P[VBIm][His], poly(1-butyl-3-vinylimidazolium lysinate), P[VBIm][Lys], and poly(1-butyl-3-vinylimidazolium arginate), P[VBIm][Arg] have been synthesized, characterized, and their CO2 absorption capacities were investigated using quartz crystal microbalance (QCM) at temperature range 288.15–308.15 and pressures up to 5 bar. Based on the absorption mechanism, the reaction equilibrium thermodynamic model is applied to correlating the experimental CO2 absorption capacities. The reaction equilibrium constant and Henry’s law constant were calculated to evaluate the efficiency of the AAPILs for CO2 absorption. In the investigated AAPILs, the CO2 absorption capacity was as follows: P[VBIm][Arg] > P[VBIm][Lys] > P[VBIm][His] > P[VBIm][Pro] > P[VBIm][Gly] > P[VBIm][Val] > P[VBIm][Ala]. The accessibility of available more amine groups in AAPIL with arginate anion is the main factor for the high CO2 absorption capacity. Also, chemical absorption of CO2 via carbamate formation was corroborated by FT-IR spectroscopy.