Abstract
Chitosan membranes with various degrees of deacetylation were prepared by casting acetic acid solutions of chitosan. The effective charge density on the membranes was calculated by Teorell-Meyers-Sievers theory from the membrane potential determined with potassium chloride. The charge density unexpectedly decreased with the increased deacetylation, suggesting the influence of decrease of the amorphous regions containing dissociable amino groups. The permeability of the membranes was determined for four simple electrolytes. At low electrolyte concentrations, permeability increased with the concentration through the Donnan effect. At high concentrations it became independent of ionic concentration and was negatively dependent on the radii of hydrated ions. The microporous membranes showed 2-3 times higher permeability than the dense membranes, while their concentration dependences were similar to each other.
