Pervaporation is proposed to be an energy-efficient technique for water removal and methanol recovery.Based on Flory-Huggins theory and Ficks law,the mass transfer of a methanol/water mixture was studied and a mass transfer model was obtained.Further experiments were carried out to verify the model.The interaction parameter between water and the polyvinyl alcohol(PVA)membrane is smaller than that of methanol,while plasticizing coefficient and diffusion coefficient of water in the PVA membrane are larger.So the membrane adsorbs,dissolves and transfers the water preferentially.If the methanol content is larger in the mixture,the interactional parameter increases and the pervaporation effect is significant.