It has been carried out a research adsorption-desorption of metal ion Cu (II), Cd (II) and Pb (II) on Sargassum duplicatum (S. duplicatum) biomass immobilized by silica gel with a continuous method using a set of adsorption equipment controlled automatically. From the optimum result of this equipment, it has been obtained that an average of flow rates Cu (II), Cd (II) and Pb (II) ions by S. duplicatum biomass immobilized by silica gel is 1.3 mL min(-1). Adsorption process of metal ions Cu (II), Cd (II) and Pb (II) on S. duplicatum biomass immobilized by silica gel is optimum at pH of 5.0 with the adsorption capacities of 280.112, 130.513 and 113.660 mu mol g(-1) respectively. On the competition adsorption, the Cu (II) ion is more adsorbed on S. duplicatum immobilized by silica gel with the adsorption selectivity coefficient (alpha)>1. The uses of 2.0 mmol L-1 HCl as eluent of Cu (II), Cd (II) and Pb (II) ions adsorbed on S. duplicatum immobilized by silica gel resulted recovery percent (%) are 98.63+/-0.56, 84.79+/-0.40 and 70.11+/-0.17, respectively. Crown Copyright (C) 2010 Published by Elsevier BM. All rights reserved.