Physical absorption of carbon dioxide in imidazole-PTSA based deep eutectic solvents

Capture of CO2 with high efficiency is essential to tackle the global warming issue that has aroused widespread attention. Herein we employed the halogen- free deep eutectic solvents (DESs) consisting of imidazole (Im) and p-toluenesulfonic acid (PTSA) to absorb CO2. The CO2 solubility in [3Im:PTSA], [3.5Im:PTSA], and [4Im: PTSA] is measured in the range of temperature from 303.15 to 333.15 K and pressure from 110 to 1500 kPa. Henry's constants of H-x and H-m and thermodynamic properties of Delta solG, Delta H-sol, and Delta S-sol are correlated from the experimental data. The comparison between the studied DESs and the reported solvents is performed based on Hm. Afterwards, the experiment-dependent Jou and Mather empirical model and fully predictive COSMO-RS model are used to calculate the CO2 solubility, which are compared with the experimental results. Finally, the interaction energies between CO2 and DESs, as indicated bymisfit, hydrogen bond, and van der Waals energies, are calculated by COSMO-RS to illustrate the absorption mechanism. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Efficient capture of CO2 is crucial for addressing global warming. This study used halogen-free deep eutectic solvents (DESs) to absorb CO2, measured solubility, compared with other solvents, and analyzed interaction energies between CO2 and DESs to illustrate the absorption mechanism.