In this work, the ion-specific electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) was extended to predict the second-order thermodynamic derivative properties and gas solubility of the ionic liquids (ILs) containing one of the IL cations ([C n mim]+, [C n py]+, [C n mpy]+, [C n mpyr]+, and [THTDP]+) and one of the IL anions ([Tf2N]−, [PF6]−, [BF4]−, [tfo]−, [DCA]−, [SCN]−, [C1SO4]−, [C2SO4]−, [eFAP]−, Cl–, [Ac]−, and Br–). The ideal-gas isobaric heat capacities of ILs were estimated by the group contribution method for obtaining the heat capacity. The model prediction results were compared with the available experimental data, and the comparison shows that the ePC-SAFT prediction is reliable for most ILs. Furthermore, one adjustable ion-specific binary interaction parameter between the IL ion and CO2 can be used to further improve the model prediction performance for the CO2 solubility in ILs.

In this work, 502 experimental data for CO 2 solubilities and 132 for Henry's constants of CO 2 in DESs were comprehensively summarized from literatures and used for further verification and development of COSMO-RS. Large systematic deviations of 62. 2, 59.6, 63.0, and 59.1% for the logarithmic CO 2 solubilities in the DESs (1:2, 1:3, 1:4, 1:5), respectively, were observed for the prediction with the original COSMO-RS, while the predicted Henry's constants of CO 2 in the DESs (1:1.5, 1:2, 1:3, 1:4, 1:5) at temperatures ranging of 293.15-333.15 K are more accurate than the predicted CO 2 solubility with the original COSMO-RS. To improve the performance of COSMO-RS, 502 data points of CO 2 solubility in the DESs (1:2, 1:3, 1:4, 1:5) were used for correcting COSMO-RS with a temperature-pressure dependent parameter, and the CO 2 solubility in the DES (1:6) was predicted to further verify the performance of the corrected model. The results indicate that the corrected COSMO-RS can significantly improve the model performance with the ARDs decreasing down to 6.5, 4.8, 6.5, and 4.5% for the DESs (1:2, 1:3, 1:4, and 1:5), respectively, and the corrected COSMO-RS with the universal parameters can be used to predict the CO 2 solubility in DESs with different mole ratios, for example, for the DES (1:6), the corrected COSMO-RS significantly improves the prediction with an ARD of 10.3% that is much lower than 78.2% provided by the original COSMO-RS. Additionally, the result from COSMO-RS shows that the σ-profiles can reflect the strength of molecular interactions between an HBA (or HBD) and CO 2 , determining the CO 2 solubility, and the dominant interactions for CO 2 capture in DESs are the H-bond and Van der Waals force, followed by the misfit based on the analysis of the predicted excess enthalpies.

Viscosity is one of the most important physical properties when developing ionic liquids (ILs) for industrial applications such as CO 2 separation. The viscosities of ILs have been measured experimentally, while the modeling work is still limited. In this work, the electrolyte perturbedchain statistical associating fluid theory (ePC-SAFT) was combined with the free volume theory (FVT) to model the viscosities of pure ILs and IL mixtures up to high pressures and temperatures, in which the ePC-SAFT was used to calculate the density as inputs for modeling the viscosity of ILs with FVT. The ILs under consideration contain one of the IL cations [C n mim] + , [C n py] + , [C n mpy] + , [C n mpyr] + , or [THTDP] + and one of the IL anions

For chemical warfare agent removal, the humidity emerges as an unavoidable challenge that significantly affects the performance of metal-organic frameworks. In this work, via density functional theory calculations, ab initio molecular dynamics and classical molecular dynamics simulations, we investigate the structural and diffusion properties of water in the pristine defect-free UiO-66, one Zr-based metal-organic framework. Through the detailed analyses of the distribution probability of water in two different cages of UiO-66, the binding interaction between water and UiO-66, the hydrogen bonding networks and resulted localized water clusters, we gain a fundamental understanding of structural and dynamics properties as well as the concentration dependence of water in UiO-66. We anticipate those theoretical results could provide insight to the competitive adsorption of water and chemical warfare agents, which eventually shows the utmost importance for the design and development of the next generation porous materials with appropriate water properties in real-life applications.

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A new mixed solvent system that consists of cholinium glycinate ([Cho][Gly]) and aqueous Nmethyldiethanolamine (MDEA) solution was developed in this work to serve as CO 2 absorbent. The equilibrium absorption was carried out to investigate the effect of solution composition, pressure, and temperature on CO 2 absorption performance. The effect of CO 2 absorption on the viscosity of the aqueous solutions was studied, and the regeneration efficiency of the aqueous solutions was also investigated. The results showed that the CO 2 absorption loading decreased with increasing [Cho][Gly] concentration and temperature, and the absorption loading strongly depended on CO 2 partial pressure. The reactivity of MDEA was significantly enhanced with the addition of [Cho][Gly]. The aqueous solution with (10 wt % [Cho][Gly] + 20 wt % MDEA) showed an optimal CO 2 absorption and high regeneration efficiency. Furthermore, the CO 2 absorption mechanism in the aqueous [Cho][Gly]-MDEA solution was explored by 13 C nuclear magnetic resonance, which indicated that the CO 2 absorption in the aqueous [Cho][Gly]-MDEA solution was a zwitterion mechanism.

ePC-SAFT-DFT is a powerful tool for studying the properties of confined ionic liquids for CO 2 separation, in which efficient algorithms are required to obtain the calculation efficiently. In this work, the feasibility of accelerating the ePC-SAFT-DFT calculation with the Chebyshev pseudo-spectral collocation method was discussed for the confined ionic liquid (IL)−CO 2 systems. In addition, a general scheme was proposed to search the electrical boundary potential. The new algorithm was further combined with the general scheme to model the confined IL−CO 2 systems. It was found that the Chebyshev pseudo-spectral collocation method can improve the efficiency of the ePC-SAFT-DFT calculation significantly. Moreover, the new algorithm can be further combined with the general scheme to efficiently describe the density profile of the IL−CO 2 system inside the electroneutral nanopores.

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