This paper reports the transport of propionic acid through an anion-exchange membrane Neosepta-AFN (ASTOM Corporation) in a two-compartment dialysis cell. These basic data have been completed by measurements of the sorption isotherm. In order to quantify the transport of acid, the following transport characteristics have been determined from time dependences of the concentration of propionic acid in both the compartments: the overall dialysis coefficient, the permeability coefficient of the membrane, the membrane mass transfer coefficient and diffusivity of acid in the membrane. (C) 2009 Elsevier B.V. All rights reserved.