The electric transport of the H2SO4 and H3PO4 mixture through two types of anion-exchange membranes (strong base: ACM; weak base: AAV) was investigated. The H2SO4 removal efficiency from the mixture and the H3PO4 retention efficiency were calculated. It was found that the effectiveness of the separation process is diminished by the association of phosphoric anions with the fixed charges which reduces the effective charge concentration. The transport of acids was quantitatively described by the model based on the extended Nernst-Planck equation and the Donnan equilibria. It satisfactorily describes the electro-membrane process except its last stage when H2SO4 concentration at the cathode side of a membrane is of a low value. When the association equilibrium between H2PO4- and the fixed charges of the ACM membrane is introduced into the model, the concentration changes of H3PO4 could be much better described. Assuming the ideal Donnan equilibrium to occur, the transport of the both acids cannot be described by the same parameter related to the membrane porosity, tortuosity and the ion diffusivities. Regarding H3PO4, different ionic equilibria were taken into account in order to show their effects on the values of optimal model parameters. (C) 2010 Elsevier B.V. All rights reserved.