(634c) High Regeneration Efficiency and Low Viscosity of CO2 Capture By Functionalized Ionic Liquid Organic Solution

To reduce the high regeneration energy consumption of traditional amine or ionic liquid aqueous solution and the high viscosity of the pure ionic liquid or saturated amine non-aqueous solution, a novel functionalized ionic liquid combined with organic solvents is innovatively proposed for CO₂ capture in this project. In this novel system, the functionalized ionic liquid tetraethylenepentamine 2-methylimidazole ([TEPAH][2-MI]) as the main absorbent which ensures high CO₂ absorption rate and loading, and the organic solvent can significantly reduce the regeneration energy consumption of the system compared with water. In addition, ethylene glycol (EG) was added as a regulator to reduce the volatility of the solvent and prevent the absorption product from being precipitated in the saturated solution. The results showed that the [TEPAH][2-MI]/NPA/EG solution had a high absorption loading of 1.72 mol/mol (28 wt% and 257 g/L). The viscosities before and after absorption were 3.47 and 6.20 mPa·s respectively, which were far less than traditional pure ionic liquids and amine non-aqueous solutions. By heating for 45 min at 120 ^oC, the regeneration efficiency of the solutions could reach 90.7% after the 5^th regeneration cycle. Moreover, the reaction mechanism was elucidated based on the results of ¹³C NMR. Polycarbamate and alkyl carbonate formed in the [TEPAH][2-MI]/NPA/EG solution during the absorption process, and then the reaction products could decompose after desorption.