Conductivity of Aqueous Solutions of Low-Molecular Chitosan

Solutions of chitosan with molecular weight (MW) of 20000, 9600, and 3700 Da are studied conductimetrically and viscosimetrically. The dependence of solution conductivity on the chitosan concentration begins to deviate from linearity simultaneously with an abrupt increase in the solution viscosity starting from concentrations of 20–30 g l^–1. The fraction of free counterions (Cl^–, CH₃COO^–) in the 0.1 g-equiv l^–1 chitosan solutions significantly depends on the sample's MW. The charge is transferred in solutions predominantly by chloride and acetate ions, with the high-MW cation barely contributing to conduction.     

Chronopotentiometric Method of Studying Electroosmosis in Systems with Ion-Exchange Membranes and Lysine Solutions

A new method of chronopotentiometric study of electroosmotic water transfer in the electromembrane system containing amino acid solution is elaborated. An electrodiffusion problem, which allows for a convective solvent transfer in the system, is formulated and solved. By comparing calculated and experimental transition times for MK-40 and MF-4SK cationite membranes in lysine monohydrochloride solutions, the electroosmotic permeability of the membranes and transport numbers of water through them are calculated. A considerably higher electroosmotic water transport through MK-40 as compared with MF-4SK is attributed to differences in their nature and structure.