In this paper, dialysis of H2SO4+Na2SO4 mixture was investigated at steady state in a two-compartment counter-current dialyzer with single passes. The dialyzer was equipped with an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan). The efficiency of separation was characterised by the recovery yield of acid, rejection of salt and four diffusion phenomenological coefficients. The phenomenological coefficients were determined by the procedure, which combined the numerical integration of the basic differential equations describing the concentration profiles of acid and salt in both the compartments. They were correlated with the acid and salt concentrations in the membrane. It was experimentally proved that the acid recovery yield was in the limits from 52% to 90%, while the salt rejection coefficient was in the limits from 0.73 to 0.89. (C) 2015 Elsevier B.V. All rights reserved.