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Author: search.filters.author.Paterson, RussellSubject: search.filters.subject.Transport Properties

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    Investigation of the Transport Properties of a Quaternary Ammonium Anion Exchange Membrane: Part 1.- —Application of Irreversible Thermodynamics to the Chloride Form
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) McCallum, Colin; Paterson, Russell
    A detailed study of the transport properties of the chloride form of a strong base quaternary ammonium anion exchange membrane has been completed. Experimental determination of isotope diffusion coefficients and electrical, salt diffusion, and osmotic properties has been made. From these data a complete irreversible thermodynamic analysis of the system in 0.1 and 1.0 mol dm–3 sodium chloride solutions has been obtained. Using primarily the frictional coefficient treatment, it is shown that the kinetic interaction between membrane ions and fixed charge contributes to a very large degree in reducing ion mobility, but that this contribution is large primarily because the membrane has very large internal ionic molality and not due to ion association. Equally, although there is considerable evidence for water structure enforcement around quaternary ammonium ions in aqueous solution, there is no evidence for this effect in the membrane. Water-to-water friction is similar to that obtained in other membrane studies on cation exchangers and to aqueous electrolyte solutions. The terminal hydroxyl groups on the quaternary ammonium fixed charges of the A104 membrane may do much to modify the unique solvation of alkyl substituted analogues. Pressure permeability and osmotic coefficients obtained by calculation indicate that the membrane is almost ideally semi-permeable with a reflection coefficient, σ, of 0.99 and 0.97 in 0.1 and 1.0 mol dm–3 salt solutions, respectively, and has a very low salt permeability.
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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.
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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.