Kinetic aspects of Donnan dialysis through Nafion-117 membrane

Chhavi Agarwal, Sanhita Chaudhury, A. K. Pandey, A. Goswami

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The transport rate of ions across Nafion-117 ion-exchange membrane in a Donnan dialysis process has been measured for mono-monovalent (Na +-Cs +) and mono-bivalent (Na +-Ba 2+, Na +-Mg 2+) ion-exchange process. This has been carried out for different salt concentrations (0.01M, 0.1M and 0.5M). The transport rate has also been calculated using appropriate form of Nernst-Planck equation. The self-diffusion coefficients of the ions and the ion-exchange capacity of the membrane have been given as input parameters in the calculations. The concentration of ions at the solution/membrane interface has been obtained from solution concentrations by the use of Donnan relation. The calculated time profile has been found to match with the experimental time profile at 0.1M and 0.5M salt concentrations. At 0.01M concentration, there is significant deviation between the two profiles, probably showing the change in selectivity of the membrane with decrease in salt concentration. The experimental and the NP calculations have been compared with the calculations based on mass balance approach as given by Miyoshi (1996, 1997, 1998) [17-19]. The NP calculations coupled with the experimental time profile, have been used to obtain the self-diffusion coefficient of Mg 2+ ion in Nafion-117 membrane.

Original languageEnglish
Pages (from-to)681-685
Number of pages5
JournalJournal of Membrane Science
Volume415-416
DOIs
StatePublished - 1 Oct 2012
Externally publishedYes

Keywords

  • Donnan membrane equilibrium
  • Ion-exchange kinetics
  • Mass balance.
  • Nernst-Planck equation

ASJC Scopus subject areas

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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