Pervaporation is an efficient membrane process for liquid phase separation and during past decades had witnessed substantial progress and exciting breakthrough in both the fundamental and application aspects. Until now, so many experimental data without any genuine and capable model were available to describe this phenomenon. The mechanism of pervaporation in polymeric membrane is described by means of a three-step process: solution, diffusion and evaporation. In this work separation of the organic-organic mixtures through polymeric membranes was modelled based on a solution-diffusion mechanism. In this model on the feed side equilibrium was assumed between the liquid phase and membrane and the components concentration at the permeate side of the membrane was considered to be zero. The UNIFAC equations were used to describe the sorption step, and the Stefan-Maxwell equation was applied to describe the traort step. The developed model was implemented to predict the separation of three different liquid binary mixtures through polyurethane (PU) polymeric membrane. The calculated permeate fluxes were compared with the results of the experiments which were reported by others. By using UNIFAC equation, the predicted results for permeate concentration and flux were found in good agreement with the experimental data in all composition ranges. Also the results obtained from the developed model were compared with results of different models based on other equations for prediction of activity coefficient. It was seen that the developed model has some advantages over other models. Keywords : Pervaporation, Modeling, Organic-Organic, Polymeric Membrane, UNIFAC.
