The purpose of the present study is to investigate the behaviour of activated carbon from apricot stones (ACAS) in a closed circuit fluidized bed (CCFB) for removal of Pb Cu Cd and Zn ions from aqueous solution The expansion characteristics of the bed are studied A homogeneous solid phase diffusion model was used to describe the mass transfer inside the adsorbent particles A piston-dispersion model was applied for the liquid phase in the bed and compared to the calculations assuming perfect mixing conditions in the whole CCFB adsorber The close correspondence between the experimentally determined adsorption in batch and fluidized bed operation modes support the observation that the CCFB can be described by a stirred batch adsorption model The concentration profile at the bed exit is satisfactorily predicted by the model thus confirming the equilibrium and kinetic parameters determined from the laboratory batch adsorption runs (C) 2010 Elsevier B V All rights reserved