Membrane parameters characteristic for the study of electrolyte solutions across microporous membranes such as salt permeability, ion transport numbers and membrane electrical resistance have been determined for a ceramic microfiltration membrane by measuring salt diffusion, membrane potential and impedance spectroscopy (IS), respectively. In order to see the effect of ion charge and concentration on these parameters, NaCl and MgCl2 solutions at different concentrations (0.001 M < c < 0.1 M) have been used, but only small differences depending on both electrolyte and concentration have been found. Changes in the different parameters due to the treatment of the ceramic membrane (2 h in a 1 M H2SO4 solution and calcined in air at 573 K for 1 h) have also been studied, and the results seem to indicate a modification (reduction) in the porosity and in the electrical nature of the original membrane. (C) 2004 Elsevier B.V. All rights reserved.