A new process is proposed for the removal of metallic (Cu(II)) compounds in the treatment of industrial waste waters: a membrane reactor with a moving bed of porous ion-exchange resins. After a comparison of various cationic resins, IRP 69, with its small particle diameter and high exchange rate, was chosen for the rest of the study. For these particles, the influence of stirring velocity and temperature on the apparent reaction rate was analyzed in a closed, stirred reactor. The conditions for obtaining the kinetic regime and rate constant were determined. A particle filterability study defined the operating conditions (circulation velocity and pressure) needed for a satisfactory compromise between power consumption and the number of modules to be set up. The first elements for a comparison between a conventional packed-bed reactor and a membrane moving particle-bed reactor are given. For the same flow rate and a conversion of 95%, the membrane reactor running under optimum conditions provides reductions by factors of 2.9 for the volume of adsorbing particles, 26 for the pressure loss, and 4.75 for the power supplied to the system. The process thus shows promise but its performance remains to be validated by a pilot study.