Preparation and Properties of a High-Performance Deep Eutectic Solvent ChCl-AEEA for Carbon Dioxide Capture

Deep eutectic solvents (DESs) have emerged as a new class of eco-friendly solvents for carbon dioxide (CO2) capture due to their excellent properties and good stability. In this work, a high-performance deep eutectic solvent ChCl-AEEA absorbent with choline chloride (ChCl) as a hydrogen bond acceptor (HBA) and aminoethyl ethanolamine (AEEA) as a hydrogen bond donor (HBD) was prepared. The formation process of the ChCl-AEEA was determined by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC); the effects of AEEA proportion in the DES β, water content ωH2O, temperature T, and pressure pCO2 on the CO2 absorption capacity of the DES were investigated. The results showed that the CO2 absorption capacity α of the DES could be as high as 0.8528 mol of CO2/mol of DES (0.3373 g of CO2/g of DES) at 313.2 K and 0.1 MPa when ωH2O was 51.9 wt % and β was 0.8. The corresponding absorption heat was measured to be −48.34 kJ/mol, indicating a low energy consumption for desorption. The absorption capacity of the DES did not change after five absorption and desorption cycles. The absorption of CO2 in the prepared DES was chemical absorption, which was confirmed by FTIR and the 13C nuclear magnetic resonance (13C NMR) spectrum.