(82a) Lactic Acid Hydrophobic Natural Based Deep Eutectic Solvents for Carbon Capture at Wide Process Conditions

Carbon dioxide (CO₂) solubility and the kinetics of absorption of CO₂ by Natural Deep Eutectic Solvents (NADES) were explored in this work. Three systems were under focus namely, carvone-lactic acid (1:1), cineole-lactic acid (1:1), and cineole-lactic acid (3:1). The CO₂ absorption conditions in the course of this work were a pressure range of 4.5 to 37 bar and at isotherms of 25 and 35 °C. The quantification of the CO₂ was in terms of mole fraction of the gas in the NADES. The process demonstrated that the absorption is influenced by the pressure positively and negatively by the temperature. Among the studied NADES systems, cineole-lactic acid (3:1) exhibits the highest capacity of CO₂ absorption at all the temperatures. A comparison was carried out between the experimental data and the COSMO-RS predictions. That revealed a systematic deviation in which all the experimental results were higher than the predictions and that deviation increases at the lower temperatures and at the higher pressure values. The kinetics of absorption also was investigated which showed that increasing the pressure made the absorption pace faster. Moreover, the system of cineole-lactic acid (1:1) showed faster absorption at 35 °C than that at 25 °C, which can be justified by the viscosity reduction. Also, heat of absorption for the tested systems was calculated based on Clausius-Clapeyron equation. The values of the heat of absorption were in the physi-sorption range and lower than the values of monoethanolamine (MEA). Heat of absorption magnitudes indicate the lower energy-intensive process of regeneration for the produced NADES. Generally, the findings direct to these NADES ability to capture CO₂ with reduced environmental effect and effective energy exploitation.