PERVAPORATION SEPARATION OF WATER ETHANOL THROUGH MODIFIED POLYACRYLONITRILE MEMBRANES

In the present work the separation of water-ethanol binary mixture through polyacrylonitrile (PAN) and its modified membranes was studied using pervaparation processes.PAN was chosen as a base polymer because of its high affinity with water. As a result, homogeneous PAN membrane has anextremely high selectivity toward water and has low fiuxes in pervaparation. Membrane morphology of PAN influences to a great extent on the membrane performance when separating the aqueous ethanol solution. This study investigates theway to control the membrane morphology and the membrane performance. The key factors affecting the membrane morphology include the membrane casting variables such as concentrationof casting solution, solvent evaporation temperature, solvent evaporation pressure, the membrane thickness and thepresence of nonsolvents in casting solution. Membranes we investigated are homogeneous, blend-type and copolymer-typePAN membranes. A statistical method was adopted in the experiment. As a consequence it was possible to effectively predict fiuxes and separafion factors using these membranes to dehydrate aqueous ethanol solution. © 1990, The Society of Polymer Science, Japan. All rights reserved.