Pervaporation separation of sodium alginate/chitosan polyelectrolyte complex composite membranes for the separation of water/alcohol mixtures: Characterization of the permeation behavior with molecular modeling techniques

Polyelectrolyte complex (PEC) membranes were prepared by the complexation of protonated chitosan with sodium alginate doped on a porous, polysulfone‐supporting membrane. The pervaporation characteristics of the membranes were investigated with various alcohol/water mixtures. The physicochemical properties of the permeant molecules and polyion complex membranes were determined with molecular modeling methods, and the data from these methods were used to explain the permeation of water and alcohol molecules through the PEC membranes. The experimental results showed that the prepared PEC membranes had an excellent pervaporation performance in most aqueous alcohol solutions and that the selectivity and permeability of the membranes depended on the molecular size, polarity, and hydrophilicity of the permeant alcohols. However, the aqueous methanol solutions showed a permeation behavior different from that of the other alcohol solutions. Methanol permeated the prepared PEC membranes more easily than water even though water molecules have stronger polarity and are smaller than methanol molecules. The experimental results are discussed from the point of view of the physical properties of the permeant molecules and the membranes in the permeation state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2634–2641, 2007