Modeling the surface tension and the interface of ten selected liquid mixtures: Correlation, prediction, and the influence of using partial molar volume

This work investigates the modeling of the surface tension and the interface of liquid mixtures. Nine binary liquid mixtures of (DMSO+alcohols), (2-Propanol+2,2,4-trimethylpentane), (Tetrahydrofuran+2-Propanol), (Tetrahydrofuran+2,2,4-trimethylpentane), and (ethano+glycerol) are considered. Additionally, one ternary liquid mixture of (Tetrahydrofuran+2-Propanol+2,2,4-trimethylpentane) is considered. Firstly, two correlations were used to model the surface tension. One of these correlations has one adjustable parameter, and the other has five fitting parameters. Then the model based on the equality of the chemical potentials at the interface and the liquid phase was used. The surface tension and interfacial composition are computed by using this model. This approach was used in two ways, including activity-based and fugacity-based models. The UNIFAC activity model and PSRK EOS equation of state were applied to compute activity and fugacity, respectively. Moreover, the effect of the partial molar volume on predictions was investigated. The results of the applied models show that the correlation with five adjustable parameters and the fugacity-based model have the best results. Also, the increase in the non-ideality of these systems results in a better performance of the fugacity-based model, therefore the application of the partial molar volume is necessary.