Sustainable ionic liquid organic solution with efficient recyclability and low regeneration energy consumption for CO2 capture

Abstract

Abstract A novel sustainable amino functionalized ionic liquid (AFIL) organic solution of tetraethylene pentamine 5-amino-4-imidazolecarboxamide/n-propanol/ethylene glycol ([TEPAH][AICA]/NPA/EG) was proposed for CO2 capture to reduce the regeneration energy consumption. The solution had an efficient absorption loading of 1.78\xa0mol·mol−1, and it still maintained a good recyclability after 10 cycles (regeneration efficiency\xa0>\xa088%). Under this condition, the regeneration energy consumption was 2.30 GJ·t−1 CO2, which was 39.5% lower than that of MEA/water. The absorption and desorption mechanisms were investigated by 13C NMR. For CO2 absorption reaction, N atom of [AICA]− combined with CO2 to form the carbamate directly, while other amino groups followed the zwitterion formation and deprotonation. Then some carbamates combined with alcohol to form the alkyl carbonates. For CO2 desorption reaction, both the alkyl carbonates and carbamates combined with AFILH+ to decompose, but the alkyl carbonates decomposed completely and a small amount of carbamates remained, indicating that carbonate was easier to decompose than carbamate. The novel [TEPAH][AICA]/NPA/EG solution with low energy consumption and good recyclability, which provides a sustainable strategy for advancing carbon capture technologies.