Acetic acid Separation as a Function of Temperature Using Commercial Pervaporation Membrane

Acetic acid was separated from a dilute mixture using a commercial polyvinyl alcohol (PVA) membrane.  Intrinsic separation characteristics of the membrane were studied as a function of temperature.  The degree of membrane swelling decreased marginally with increase in feed temperature. At 25oC the maximum degree of swelling was found out to be 46.3%, which reduced to 39.5% at 65oC. Although the pervaporation flux increased with increasing temperature of the liquid feed mixture, the separation factor decreased. From the temperature dependence of diffusion and permeation values, the Arrhenius apparent activation parameters for water permeation were estimated. Diffusion and partition coefficient for water and acid were found to increase with temperature, but the diffusion coefficient of water was substantially higher than that of acetic acid at a constant feed concentration. The membrane used in the present study could tolerate highly concentrated corrosive acetic acid, thus may be useful for dehydration of other organics.