Browsing by Author "Gardner, Colin R."

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    Comparison of the Transport Properties of Normal and Expanded Forms of a Cation-exchange Membrane: Part 2.—Self-diffusion and Electrical Properties of Membranes in the Sodium Form in Concentrated Sodium Chloride
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (11), 1972) Ferguson, Hugh; Gardner, Colin R.; Paterson, Russell
    The influence of shrinking and increasing salt uptake on the transport properties of normal and expanded membranes has been examined. Isotopic diffusion coefficients from sodium and chloride ions were found to be functions of changing tortuosity and membrane electrolyte molality. Tortuosity corrected coefficients agreed closely with those of sodium and chloride ions in aqueous sodium chloride at equal molalities. Diffusion coefficients for tritiated water were constant, when corrected for tortuosity, and equal to the diffusion coefficient of tritiated water in pure water. From electrical measurements, it is shown that the ratio of solvent-fixed velocities of sodium and membrane-sulphonate ions is constant over the experimental range of conditions. The sulphonate ion is more mobile than sodium on this frame of reference and similar in behaviour to chloride or nitrate in free aqueous solution. All data indicate the validity of a simple aqueous model for membrane transport phenomena.
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    Comparison of the Transport Properties of Normal and Expanded Forms of a Cation-exchange Membrane: Part 3—Application of Irreversible Thermodynamics and Nernst-Planck Theories to Membranes in Concentrated NaCl Solutions
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (11), 1972) Gardner, Colin R.; Paterson, Russell
    The Onsager mobility and frictional coefficients for the normal and expanded membranes have been calculated when the external solution was 1.0 M NaCl. The validity of a number of methods of approximation of minor coefficients is examined. The results have been reproduced using a ternary electrolyte calculation in which mobility coefficients for the salt-free membrane were combined with those of aqueous sodium chloride. Calculated transport measurements agree well with those obtained experimentally. Finally the validity and probable errors of the Nernst-Planck theory are examined.