Mass Transfer Modeling in Pervaporation Based on Multi-fields Synergy Theory*

To provide a theoretical basis for optimizing the pervaporation procedure, a mass transfer model for pervaporation for binary mixtures was developed based on the multi-fields synergy theory. This model used the mechanism of sorption-diffusion-desorption and introduced a diffusion coefficient, which was dependent on the feed concentration and temperature. Regarding the strong coupling effect in the mass transfer, the concentration distribution in membrane was predicted using the Flory-Huggins thermodynamic theory. The batch experiments and other experiments with constant composition were conducted using a modified chitosan pervaporation membrane to separate tert-butyl alcohol (TBA)-water mixtures. The parameters of the mass transfer model were obtained from the flux of the experiments with a constant composition and the activity coefficients available through phase equilibrium equation, using the Willson equation in the feed side and the Flory-Huggins thermodynamic theory within the membrane. The simulation results of the experiments are in good agreement with the results of the experiments.