Ion exchange experiments were carried out in a fixed-bed column employing the binary systems Cu2+-Na+ and Zn2+-Na+. Amberlite IR 120 was used as the ion exchange resin. The ion exchange dynamics within the column was described by a model considering the external mass transfer and the diffusion within the particle. A linear driving force model was used to represent the mass transfer within the resin particles. The model considered the thermodynamic equilibrium on the liquid-solid interface, which was described by the Langmuir isotherm and by the mass action law. The results indicate that both models represent well the ion exchange dynamics in all cases. (C) 2011 Elsevier B.V. All rights reserved.