Model of mass transfer in polyvinyl alcohol membrane for isopropanol/water mixture

Based on Flory–Huggins theory and Fick's law, the model of mass transfer in polyvinyl alcohol (PVA) membrane for isopropanol/water mixture was established. The predicted results fit well with the experimental data. The interactional parameter between water and PVA membrane is less than that between isopropanol and PVA membrane, which validates that water is preferentially adsorbed and dissolved in PVA membrane. The plasticizing coefficient and diffusion coefficient at infinite dilution of water are larger than those of isopropanol, which shows that the dissolution and permeation of water are greater than those of isopropanol in PVA membrane. So water permeates preferentially. Both the interactional parameter between water and isopropanol in PVA membrane and that in feed rise with the increase of isopropanol content in feed, which shows that the larger isopropanol content is, the higher selectivity of PVA membrane is and the more remarkable separation effect of pervaporation process is.