Pervaporation is a nonequilibrium membrane process. The pressure or chemical potential gradients are the factors that determine the irreversibility of membrane transfer in pervaporation. In this work, we consider the opportunity of describing and approximating pervaporation data using a nonequilibrium thermodynamic approach. Pervaporation curves for a wide range of feed solution concentrations have been built based on data on a few binary systems. The thermodynamic properties of feed solutions were calculated using vapor-liquid equilibrium data. The sigmoidal Boltzmann function, Gauss function and Praal equation were used to approximate vapor-liquid equilibrium data. Approbation of proposed variants in the construction of pervaporation curves was carried out for five binary systems: ethanol-water at 50 degrees C and 60 degrees C, acetone-water at 30 degrees C, benzene-cyclohexane at 25 degrees C, methanol-methyl-tert-butyl ether at 25 degrees C, and ethanol-butanone at 55 degrees C. The agreement between calculation results and experimental data is in the limits which are sufficient for applied estimations. (c) 2014 Elsevier Ltd. All rights reserved.