Double membrane diaphragm technique for absolute measurements of diffusion coefficients

Authors:
  • DED. E. Elrick
    D. E. Elrick
  • DSD. E. Smiles
    D. E. Smiles
  • RWR. A. Wooding
    R. A. Wooding
Publisher website
Google Scholar
Abstract
A new technique for measuring diffusion coefficients utilizing two thin porous membranes separated by a spacer of known cross-sectional area and thickness is presented. The method permits absolute measurements of diffusion coefficients of chemical and biological materials in solution. The technique is based on the free-diffusion space between two membranes, thus avoiding the problems of solute-membrane interactions and tortuosity of the pore space that are present with single membrane diaphragms. Diffusion coefficient measurements of 5 × 10–4 M NaCl and 5 × 10–4 M KCl are in good agreement with values reported in the literature.