The specific adsorption of Mg+2 and S2O82- ions onto the gamma-alumina particle surface has been dernonstrated. An estimation algorithm based upon the correlation between electrophoretic mobility and conductivity increment experimental data, employing a dynamic Stern-layer theory, has been developed and used to get the adsorption parameters into the Stern layer for different gamma-alumina/Mg+2 and S2O8-2 aqueous solutions interface. (C) 2003 Elsevier Inc. All rights reserved.