| Anthropogenic carbon dioxide (CO2) emissions are mainly caused by combustion of carbon-based fuels, primarily coal, oil, and natural gas. Particularly, CO2 capture and separation processes in pre-combustion, post combustion, oxy-fuel combustion, and natural gas sweetening mainly employ eco-unfriendly high volatile capturing media such as amines and methanol. However, with regard to the establishment, development, and expansion of the carbon capture and sequestration (CCS) projects, new environmentally benign capturing media should be developed as substitutes for traditional detrimental CO2 capturing materials.Ionic liquids (ILs) known as "green solvents" and also "designer solvents", possess several favorable properties to trap CO2 as well as to be combined with other materials to form novel capturing media with favorable structures for high performance on CO2 uptakes. Thus, new promising IL-incorporated CO2 capturing media have recently been studied by researchers.In summary, amine groups have been attached to either the cation or anion of the IL in order to include high CO2 capacity of amines in ILs. Reversible ILs have been synthesized with high chemical stability and less required regeneration energy compared to the amine solvents. Supported liquid membranes (SLMs) utilize ILs as their selective materials-due to low volatility, high viscosity, and high CO2 capacity of the ILs-to enhance stabilization and CO2 selectivity of the SLMs. Various porous materials such as metal organic frameworks (MOFs) and silicas have been impregnated with ILs to tune their pores morphology to achieve strong desirable selective interactions between CO2 and the porous support.Herein, by conducting a sequence of laboratory experimental works, solubility data of CO2 in the IL [AMIM]+[Tf2N]", 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, methanol (CH3OH), and their mixtures at different combinations of CH3OH and IL (80 wt% IL+20 wt% CH3OH,50 wt% IL+50 wt% CH3OH, and 20 wt% IL+80 wt% CH3OH) at temperatures 313.2,333.2, and 353.2 K and pressures up to 6.50 MPa were measured using a high-pressure view-cell technique. Methanol is widely applied in the well-known Rectisol process for CO2 capture. However, the main problems with this process are the necessity of deep cooling and high volatility of methanol which requires a huge amount of refrigeration energy and also causes environmental problems. Here we provided the concept that an IL-methanol solvent can reduce the amount of volatile solvent in the gas phase so that the process can be operated at an optimized condition-e.g. higher temperature for the same other operating conditions comparing to the conventional methanol process-in which less utility energy be required.Moreover, in order to justify the applicability of UNIFAC model for these systems, the experimental results were correlated and the predicted solubility data were obtained by extending the new group binary interaction parameters (amn and anm). The comparison of CO2 solubility data and CO2 Henry’s constants between experimental data and predicted results shows that the solubility of CO2 in pure IL and pure methanol as well as in their mixtures can be well predicted by the UNIFAC model. This indicates that the UNIFAC model for ILs is a powerful predictive model. |
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