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The pseudolattice theory can be used to describe the thermodynamic and transport properties of ionic liquids. To determine the surface tension of these systems, the surface area can be related to the pseudolattice cell size. In the pure ionic liquids, due to the great number of ionic contacts, the short-range repulsive ion-ion interactions are significant and the ion-solvent interactions are absent. According to the pseudolattice theory and by using some approximations we obtain a simple linear correlation for the surface tension of ionic liquids. The parameters of this linear regularity can be used to estimate the surface tension in a wide temperature range and to predict the surface tension of binary mixtures of ionic liquids. The trend of change of the calculated surface tensions of mixtures and their values are consistent with the experimental data.

Recently, there has been a growing interest in CO2 capture using ionic liquids (ILs). To determine the CO2 absorption potential of ILs and their selectivity in the presence of other gaseous components in the mixture, the solubility of ILs at various operating conditions and the influence of impurities/additives such as water and toluene should be evaluated. Carbon capture capacity of the ILs can be examined using various methods such as experiments, thermodynamic approaches including Equations of State (EOSs), and molecular-based modeling. In this research work, the extended Peng–Robinson (PR) and Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) EOSs are utilized to assess the solubility and selectivity of CO2 in ILs through comparing the modeling results with experimental data. PC-SAFT and PR parameters are determined by employing the experimental density data. Modeling results reveal that the solubility values estimated by the PC-SAFT due to considering the association effects have a lower deviation (or a better performance) than PR EOS based on the magnitudes of Absolute Average Deviation (AAD %). The AAD (%) for [bmim][BF4], [bmim][PF6], [bmim][Tf2N], [hmim][Tf2N], [hmim][FAP], and [hmim][FAP] are calculated using PR EOS and PC-SAFT EOS, which are 2–5.7% and 3–7.5%, respectively. Furthermore, ternary systems of CO2 + ILs + water and CO2 + ILs + toluene are modeled to determine the effect of water and toluene on the gas solubility in ILs and viscosity of ILs with PC-SAFT EOS. Based on the results, low concentrations of water (0.1 wt%) have a negligible influence on the CO2 solubility in ILs. However, with increasing the water concentration, the solubility of water reduces significantly. On the other hand, the viscosity of ILs is reduced with increasing the water concentration. Viscosity reduction in the hydrophilic ILs is significant. It seems promising to add water up to 10 wt% to hydrophilic ILs, since a decrease in the viscosity to an amount close to the viscosity of water and a decrease in solubility by 9% are experienced. Finally, the selectivity of [hmim][Tf2N] in separation of CO2 from mixtures containing H2S, SO2, CH4, and H2 are reported. Based on the results, [hmim][Tf2N] is not appropriate for separation of CO2 from streams with a high concentration of H2S and SO2 gases.

In the present work, we have studied the targeted drug delivery performance of the folic acid functionalized boron nitride oxide (BNO-FA) for fludarabine (Flu) and cytarabine (Cyt) anticancer drugs by means of density functional theory (DFT) and molecular dynamic (MD) simulation. Calculations have also been performed on boron nitride (BN) and boron nitride oxide (BNO) nanosheets for better comparison. The obtained results indicate that the absorption of drugs on the nanocarriers is spontaneous and exothermic. The strongest interactions were observed in BNO-FA-Cyt and BNO-FA-Flu complexes. All complexes are polar, which can indicate their solubility in aqueous medium. It is found from the quantum molecular descriptors that BNO and BNO-FA nanocarriers are more reactive than BN nanocarrier. With adsorption of drugs on the nanocarriers, the reactivity increases. The results of NCI calculations indicated that the electrostatic interactions are responsible for the adsorption of drugs on nanocarriers. The results of the MD simulations indicated that Flu/Cyt drugs are strongly adsorbed on the BNO-FA nanocarrier.

Ionic liquids (ILs) show great potentials for CO2 capture. In this research, we perform molecular dynamics (MD) simulations to explore bulk and interfacial behaviors of [Bmim][Ac] and [Bmim][BF4] ILs with and without CO2, in terms of transport phenomena and thermodynamics aspects. Physiochemical properties of pure ILs are calculated; structural properties such as radial distribution function (RDF) and self-diffusivity of the cations and anions are determined at various conditions. Great agreement is achieved between the experimental and calculated properties. Diffusion coefficients obtained for the cations and anions of the ILs are in the range of 3 × 10−12 to 34 × 10−12 m2/s. The cations have a higher diffusivity than the anions. It is found that the anion has an important effect on CO2 absorption, based on the coordination/structuring of CO2 around the cations and anions in the bulk systems of IL-CO2, as well as the comparison of volume expansion of the bulk system with that of pure ILs. With the addition of CO2 to ILs, the volume expansion is relatively smaller, compared to other organic solvents. The diffusion coefficient of CO2 in ILs varies from 1 × 10−10 to 3 × 10−10 m2/s, depending on temperature, CO2 concentration, and mixture viscosity. At the interface, association density between the cation and anion molecules increases. Upon CO2 diffusion, a dense interfacial layer is created that interrupts the association of the cation and anion, leading to a reduction in the interfacial tension. MD simulations also show that the diffusion of CO2 in the bulk occurs slowly. This study benefits designing appropriate ILs for various energy and environment applications under different process and thermodynamic conditions.

It is the purpose of this paper to determine the volumetric properties of some ionic liquids (ILs) using the modified version of Tao–Mason (TM) equation of state (EOS). The studied ILs include the cations: imidazolium, phosphonium, pyridinium, pyrrolidium and anions: tetrafluoroborate, bis(trifluoromethylsulfonyl) imide, and hexafluorophosphate. The densities of these compounds were calculated by the usage of the modified TM EOS at several temperatures and pressures. The most important parameter in this EOS is the second virial coefficient which is calculated from a two-parameter corresponding states correlation along with two constants enthalpy of vaporization and molar density both at 298 K. The other remaining parameters (i.e., α(T) and b(T)) that appeared in the EOS were calculated from simple equations. Novelty of this work is the modification of the original TM EOS and usage of enthalpy of vaporization and molar density instead of critical and Boyle parameters in the original TM EOS. The good harmony between the calculated and literature density values of ILs confirms the ability of the modified TM EOS in predicting volumetric properties of this class of fluids. Overall average absolute deviation (AAD) of the calculated densities from 3394 experimental data points is 1.48%.

Using the evaporating method, the solubility of barium nitrate was determined in various mixtures containing water and ethanol at 25.0 °C. The results show that the solubility of Ba(NO3)2 decreases when increasing mass percent of ethanol in the mixtures. This trend is along with decreasing the dielectric constant of “water + ethanol” mixture. Moreover, it can be concluded that the total solubility of Ba(NO3)2 may be regarded as the sum of two contributions; one referring to the free ions in the solution and the other to the BaNO3+–ion pair which is formed in the saturated solution. Estimating the formation constant, KA, for the reaction, Ba(soln)2+ + NO3(soln)− ⇄ BaNO3(ion-pair)+ according to Bjerrum or Fuoss models, it is quite easy to evaluate the contributions of free ions and BaNO3+ (ion-pair) to total solubility.

Using Solvent Evaporating and Atomic Emission Spectrophotometric methods, the solubility of NaF in water at 25 °C was determined. Comparing the value of the thermodynamic solubility product constant, Ksp(th), (Ksp(th) = exp(− ΔGdiss° / RT)) of NaF to the value which is obtained from the observed solubility, s/mol L−1, and activity coefficients, f+ and f−, which are estimated upon the extended Debye–Huckel law, Ksp′ = [Na+][F−]f+f−, revealed a great difference. The difference has satisfactorily been explained using a combination of Debye–Huckel law and Ion-Association Theory.