COSMO-RS Exploration of Highly CO2-Selective Hydrogen-Bonded Binary Liquid Absorbents under Humid Conditions: Role of Trace Ionic Species

It is critical to improve carbon capture efficiency while reducing costs to popularize carbon capture and storage. Considering the green chemistry and engineering objectives, this study theoretically explores the CO2 absorption capacity of 1,533,528 hydrogen-bonded mixtures, i.e., deep eutectic solvents in a broad sense. Exhaustive statistical thermodynamic calculations well explain the experimental reports; it is confirmed that deep eutectic solvents containing ionic compounds have higher CO2 selective absorption capacity than those composed of non-ionic species. Quantitative evaluation of hydrogen-bonding interaction also predicts that the capacity is higher when the ionic compounds work as hydrogen-bonding donors. This is because the trace ionic species weaken the hydrogen-bonding network in the mixtures to improve CO2 physisorption.

Automated summary

Improving carbon capture efficiency and reducing costs are crucial for the widespread adoption of carbon capture and storage. This study examines the CO2 absorption capacity of 1,533,528 hydrogen-bonded mixtures, known as deep eutectic solvents, from a perspective of green chemistry and engineering. The findings confirm that deep eutectic solvents containing ionic compounds exhibit higher CO2 selective absorption capacity compared to those composed of non-ionic species. The quantitative evaluation of hydrogen-bonding interaction further predicts that the capacity is enhanced when the ionic compounds function as hydrogen-bonding donors, as they weaken the hydrogen-bonding network in the mixtures and improve CO2 physisorption.