Insights into choline chloride–phenylacetic acid deep eutectic solvent for CO2 absorption

Abstract

The properties of choline chloride plus phenylacetic acid deep eutectic solvents in neat liquid state and upon absorption of CO₂ are analyzed using a theoretical approach combining quantum chemistry using Density Functional Theory and classic molecular dynamics methods. This study investigates the physicochemical properties, structuring, dynamics and interfacial behavior of the selected deep eutectic solvent from the nano-size point of view to infer its viability for effective CO₂ capture. DFT results provided information on the mechanism of short-range interactions between CO₂ and the studied DES, showing a better performance than previously studied DES. The mechanism of CO₂ capture is analyzed considering model flue gas, showing a two-stage process with water, CO₂ and N₂ molecules developing adsorbed layers at the interface but in different regions. Water adsorbed layers would delay the migration of CO₂ molecules toward bulk liquid regions, which should be considered for developing large-scale applications.