(179a) Combined Experimental and Theoretical Thermophysical Properties Investigation of Deep Eutectic Solvents for Gas Capture Applications

Deep eutectic solvent (DES) produced by using various hydrogen bond acceptors (HBA) (e.g. betaine, alanine, choline chloride) with organic acids and sugars (e.g. citric acid, phenylacetic acid, levulinic acid and fructose) at various molar mixing ratios. Thermophysical properties including water content, thermal stability, density and gas solubility of CO₂ and N₂ were experimented at different isotherms for wide pressures range up to 50 bars. Moreover, detailed rheological experiments were conducted on the studied materials to obtain viscosity. Moreover, a density functional theory (DFT) and classical molecular dynamics (MD) methods have been used for investigating the physicochemical properties, structuring, dynamics and interfacial behavior of the studied NADES from the nanoscopic point of view to infer its viability for extensive usage. A pressure driven physisorption mechanism was observed and for the studied eutectic solvents, which were repeatable for various times without any degradation in the solubility performance. Experimental studies showed that presented materials appreciable CO₂ capture performance at low corrosion effect when compared with the most common amine-based CO₂ capture agents. No hysteresis was observed and no significant swelling tendency of the samples was recorded. Rheological experiments were studied to describe the dynamic flow behavior of the solvents. CO₂ absorption mechanism is evaluated by studying the behavior of the liquid – gas and interface. DFT simulations yielded with an accurate quantification of short-range interaction; liquid state was also characterized via middle-range as well as long-range interactions together with volumetric effects. The low cost, non-toxic and low-corrosive physical properties of the presented solvents can be considered as an environmentally promising alternative for effective CO₂ capture agents.