Experimental data and modeling of the CO₂ solubility in 2-methylimidazole aqueous solution

CO₂ capture plays a critical role in reducing carbon emissions. Novel chemical absorption media, such as imidazole aqueous solutions, have been extensively studied as potential candidates. In this work, new experimental data of CO₂ solubility in 5–30 wt% 2-methylimidazole (2-MeIm) aqueous solutions at 293.15–313.15 K were measured. The Cubic-Plus-Association equation of state (CPA EoS) with the pseudo chemical reaction approach has been proposed to model the CO₂ solubility in the 2-MeIm aqueous solutions. The CPA model can describe well the saturated vapor pressure (1.1%), liquid density (0.5%) and vapor–liquid equilibrium data (14%) of 2-MeIm aqueous solutions. Temperature dependent binary interaction parameters between 2-MeIm and CO₂ are needed in order to satisfactorily represent the phase equilibrium data of the 2-MeIm-H₂O-CO₂ ternary systems (11%) in the temperature range of 293.15–393.15 K, which covers all the decarbonization process operation conditions. With the pseudo chemical reaction approach within CPA EoS, it is possible to distinguish the physical and chemical effects of CO₂ solubility in chemical absorbents. This work provides the experimental and model basis for further research and application of the novel imidazole-based separation media for CO₂ capture.