PLASTICIZATION OF CHITOSAN MEMBRANE FOR PERVAPORATION OF AQUEOUS-ETHANOL SOLUTION

The process of pervaporation in which two components diffuse through a nonporous polymer membrane was modelled when one of the penetrants ca n exert a plasticization action to the membrane material. Thereat a ph enomenological model was employed for describing the plasticization ef fect on the diffusivities for penetrants in the membrane. The sorption equilibria and permeation fluxes for aqueous ethanol solutions in a c hitosan membrane were measured, and the permeation fluxes for water we re compared with those predicted by the proposed model. The concentrat ion of sorbed water was linear with its weight fraction (x(A)) in the feed solution, whereas the permeation flux of water was affected by th e plasticization action of sorbed water to the polymer. This plasticiz ation effect on the diffusion process can be simulated in terms of the proposed phenomenological model.