CO2 capture by task specific ionic liquids (TSILs) and polymerized ionic liquids (PILs and AAPILs)

Abstract

In the present study, new ionic liquids (ILs) such as task specific ionic liquids (TSILs), polymerized ionic liquids (PILs), and amino acid-based polymerized ionic liquids (AAPILs) were synthesized and their efficiency for capturing CO2 was studied. Nitrile imidazolium-based TSILs with different alkyl chain length and different anion ([DDS], [TFMS], [SBA], [BS], [DOSS]), PILs consisting of [VBTMA], [VBTEA] and [METMA] cations and [BF4],[Cl], [NO3], [PF6] and [TFMS] anions and AAPILs incorporating [VBTMA] as cation and [Arg], [Pro] as anions were synthesized. The results showed that the CO2 sorption increases as alkyl chain length increased and [C2CNDim][DOSS] gave the highest CO2 sorption among the TSILs, which reach up to 0.55mol fraction at 10bar, 298K. In polymerized ionic liquids the CO2 sorption capacity increases in polymeric forms than monomeric forms. To enhance the efficiency of PILs for adsorbing CO2, AAPILs have been studied. The results showed that the AAPILs are capable of capturing CO2 more than TSILs and PILs as they have functionalized amine tethered at the anion. The result of CO2 sorption showed that even at low pressure (Peq 0.7bar) and 298K, the AAPILs [VBTMA][Arg] and [VBTMA][Pro] absorbed 0.530 and 0.38mol fractions of CO2.