Transport properties of cellulose acetate osmotic membranes

TLDR

The study proposes a homogeneous diffusion model to explain the observed transport behavior. The model applies Fick's law to describe water and salt diffusion in cellulose acetate membranes. Measured diffusion and distribution coefficients for water and sodium chloride in cellulose acetate osmotic membranes vary with acetylation degree, with water diffusion ranging from 5.7×10⁻⁶ to 1.3×10⁻⁶ cm²/s and salt diffusion decreasing from 2.9×10⁻⁸ to 3.9×10⁻¹¹ cm²/s as acetyl content rises from 33.6 % to 43.2 %.

Abstract

Abstract Diffusion and distribution coefficients of water and sodium chloride have been measured in cellulose acetate osmotic membranes. These coefficients have been found to vary with the degree of acetylation of the cellulose ester. The diffusion coefficient of water varies from 5.7 × 10 −6 to 1.3 × 10 −6 cm. 2 /sec., and the diffusion coefficient of salt varies from 2.9 × 10 −8 to 3.9 × 10 −11 as the acetyl content is increased from 33.6 to 43.2 wt.‐%. A homogeneous diffusion model is proposed which describes the observations in terms of Fick's law.