A critical analysis of transport properties (diffusion, osmotic flux, conductivity, permeability) of Nafion membrane was carried out. Several correlations were elaborated to provide a consistent description of these properties in a wide range of electrolyte concentrations and membrane hydration states. A model for a sulfur dioxide depolarized electrolyzer (SDE) based on these new equations has been validated by experiments carried out with different electrode materials and electrolytes. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.