Prediction of the Surface Tension, Surface Concentration and the Relative Gibbs Adsorption Isotherm of Non-ideal Binary Liquid Mixtures

Surface properties of binary mixtures of 1,2-ethanediol, 1,2-propanediol and 1,4-butanediol with acetonitrile have been measured by the surface tension method at T = 298.15 K and atmospheric pressure. The surface tension has been predicted based on the Suarez method. This method combines a model for the description of surface tension of liquid mixtures by using the UNIFAC group contribution method for calculation of activity coefficients. Also, the results have been discussed in terms of surface concentration and lyophobicity using the extended Langmuir isotherm. The results provide information on the molecular interactions between the unlike molecules that exist at the surface and the bulk phase. Finally, experimental values of the surface tension have been correlated by the Redlich–Kister and Wang–Chen polynomial equations over the whole mole fraction range.