Diffusion in ion selective membranes

Caramazza, Raffaele; Dorst, W.; Hoeve, A. J. C.; Staverman, A. J.

doi:10.1039/tf9635902415

Cited by 13 publications

(5 citation statements)

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“…This deviation may not be significant in view of the inexact theoretical basis of Eq. [3]. It is in the expected direction because the coions tend to be concentrated into those regions of the resin where the fixed charges are least concentrated and these are the regions least obstructed by polymer chains.…”

Section: Discussionmentioning

confidence: 94%

“…Another reason for undertaking the work was that when Spiegler (2) published his frictional treatment of transport in ion-exchange membranes he also suggested a simple, though approximate, method of estimating all the frictional coefficients from a limited amount of experimental data which included tracer diffusion coefficients. Spiegler's scheme has never been given a well-defined test although his approximations have been criticized several times (3,4). The data given in this paper have been obtained in the course of collecting sufficient data to use Spiegler's method.…”

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confidence: 99%

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Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

McHardy¹,

Meares²,

Thain

1969

J. Electrochem. Soc.

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The tracer diffusion coefficients of Na + , Cs+ , Sr2 + , and Br− in a homogeneous cation‐exchange membrane have been measured in the homoionic counterion states over the external solution concentration range 0.005–1.0 equiv/liter and in the Na++Cs+ and Na++Sr2+ heteroionic counterion states over the whole equivalent fraction range at 0.02 and 0.10 equiv/liter total external concentration. Steady‐ and transient‐state permeation and diffusion techniques have been used. The results show that the resin material is essentially uniform apart from a small volume of material of low crosslinking which forms a labyrinthine network interpenetrating the main structure. This labyrinthine network is important mainly in the diffusion of Br− at low external concentrations. In concentrations above about 0.02 equiv/liter the diffusion coefficient D Br of Br− does not vary greatly either with concentration or with counterion type. D Br is greatest in the Cs+ state and least in the Na+ state. These observations and the way in which D Br varies with the equivalent fraction of the counterions in the heteroionic states can be explained by considering the expected frictional interactions between Br− coions and the counterions and by the influence of the local variations in electric potential on the movements of the ions.The diffusion coefficients of all the counterions increase as the external concentration is increased. When these diffusion coefficients are compared with the diffusion coefficients in aqueous solutions Na+ is seen to be the least retarded in the membrane and Sr2+ the most retarded. The observed behavior can be understood qualitatively in terms of the relative roles of “chain” and “volume” diffusion as suggested by Jakubovic et al. (20). A quantitative theory of these mechanisms has not been developed, but the relevance of theoretical treatments of the effects of electric potentials on counterion mobilities in polyelectrolyte and micellar solutions is pointed out. When the membrane is in a heteroionic state the diffusion coefficients of both counterions decrease when the equivalent fraction of Na + , the thermodynamically nonpreferred ion in each mixture, is increased. This behavior is consistent with the mechanism of diffusion discussed above and with the expected distribution of the counterions in a heteroionic state of an exchanger which has the structure deduced from the behavior of the Br− ions.

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Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 99%

Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

McHardy¹,

Meares²,

Thain

1969

J. Electrochem. Soc.

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“…This result is in accordance with literature. Caramazza et al [14] found a concentration-independent diffusion-coefficient for coions (Cl-) in sulphonated polystyrene membranes. However, Schldgl [ 131 reports a slow decrease of the diffusion coefficient of the coion towards higher solution concentrations in PPS-membranes but he conceded that his values (using NaBr) measured in a concentration range below 0.4 mol * I -' may be somewhat uncertain.…”

Section: Resultsmentioning

confidence: 99%

Self‐Diffusion of ¹⁸F‐Ions in a PPS‐Cation‐Exchange Membrane

Daniel

Seidel

Sattler

et al. 1993

Ber Bunsenges Phys Chem

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“…A series of experiments in idealized systems to evaluate these couplings was proposed by Speigler (1938). Several authors (hlackey and Meares, 1959;Caramazza et al, 1963;Lightfoot and Scattergood, 1963;Scattergood and Lightfoot, 1968) have performed the experiments and have concluded that the interactions are not always negligible.…”

Section: Conclusion and Significancementioning

confidence: 99%

Mass transfer characterization of Donnan dialysis

Lake

Melsheimer

1978

AIChE Journal

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Donnan dialysis is a relatively new ion exchange process using ion exchange membranes to permit continuous operation. Potential applications exist in many areas where traditional columnar ion exchange, requiring a regeneration cycle, is currently used. A mathematical model was developed. Mass transfer parameters for the model were determined from laboratory data and correlated with the system operating variables.

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Diffusion in ion selective membranes

Cited by 13 publications

References 3 publications

Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

Self‐Diffusion of ¹⁸F‐Ions in a PPS‐Cation‐Exchange Membrane

Mass transfer characterization of Donnan dialysis

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Diffusion in ion selective membranes

Cited by 13 publications

References 3 publications

Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

Diffusion of Radiotracer Ions in a Cation-Exchange Membrane

Self‐Diffusion of 18F‐Ions in a PPS‐Cation‐Exchange Membrane

Mass transfer characterization of Donnan dialysis

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Self‐Diffusion of ¹⁸F‐Ions in a PPS‐Cation‐Exchange Membrane