Surface tension and interfacial compositions of binary glycerol/alcohol mixtures

Abstract

The main aim of this research was to study the surface tension and interfacial composition of different binary mixtures of glycerol and alcohols. To achieve this aim, mixtures of glycerol and ethanol, 1-propanol, 2-propanol, and 1-butanol were prepared. By using the Du-Nouy ring method, surface tensions were experimentally measured as a function of composition in the temperature range of (293–333) K. The equality of chemical potentials of components at the surface layer and bulk liquid was considered for simultaneous prediction of surface tension and composition. The model was employed by using different approaches, including an activity based and a fugacity-based method. The UNIFAC activity model and PSRK EOS were used to calculate the activity and fugacity coefficients, respectively. The results of this study showed that the ability of the activity-based approach is limited (overall AADσ = 26.78%) while the fugacity-based method successfully predicted the surface tensions of the studied mixtures (overall AADσ = 1.84%). Our hypothesis is that the fugacity-based method was more accurate because it accounted for the partial molar area of the components.