A comparative study of the electro-osmotic behavior of cation and anion exchange membranes in alcohol-water media

• The electro-osmotic behavior of cation and anion exchange membranes has been compared.
• The influence of the kind of alcohol, methanol or ethanol, has been analyzed.
• Concentration polarization effects are higher for Nafion membrane in ethanol solutions.
• Neosepta anion exchange membrane in methanol-water solution presents the lowest electro-osmotic permeability.

Fuel flow coupled to the migration of ions is an important aspect of direct alcohol fuel cells, since it strongly affects the fuel cell performance. Solvent uptake and electro-osmotic transport in alcohol-water media have been investigated for different ion selective membranes. Cation and anion exchange membranes, and methanol and ethanol were used to assess the influence of the ion nature of the membrane and the type of alcohol. Current-voltage curves were also measured to determine the values of the limiting current density of each membrane system and analyze the influence of the concentration polarization effects on the measure of the electro-osmotic flow. The obtained results indicated that both the ionic nature and the type of alcohol affect the electro-osmotic transport. The membrane system with the anion exchange membrane and methanol-water solvent presented the lowest electro-osmotic permeability and a lower influence of the concentration polarization effects.

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