Diffusion of Saccharides and Sugar Alcohol Sorbitol in Chitosan Membranes and Beads
Diffusion coefficients of different sugars and the sugar alcohol sorbitol have been determined by two different experimental setups: mass transfer through a flat membrane in a diffusion cell and effusion experiments with beads in a batch stirred vessel. Diffusion experiments show highly consistent data with low uncertainties and high regression coefficients, while effusion experiments suffer from larger experimental uncertainties. For the diffusion through a chitosan membrane at 25°C, typically one-third of the free molecular diffusion coefficient is found, whereas at 40°C only one-quarter of it is reached. The influence of molecular size, structure, and temperature on the transport properties is discussed in detail. Diffusion coefficients of different sugars and sorbitol were determined by mass transfer through a flat membrane in a diffusion cell and by effusion experiments with beads. The membrane technique provided more accurate results and better reproduci-bility. The effects of molecular size, structure, and temperature on transport properties are discussed in detail. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.