A commercial powdered organoclay in a mixture with inert sand particles was used to study its capability for removal of a crude oil from salty water in a fixed bed adsorption column. For this purpose, after obtaining adsorption isotherm, the fixed bed breakthrough experiments were accomplished. In addition a dispersed plug flow model with an overall mass transfer resistance through column was proposed and solved numerically. The axial dispersion coefficient (D-L) and the overall mass transfer coefficient (K-F) were estimated using the experimental data and Nelder-Mead simplex optimization method. The results of modeling and optimization showed that the presence of inert particles and agglomeration of powdered organoclay decrease the mass transfer coefficient extremely. This parameter is also decreased by increasing of bed height and organoclay percentage in the mixture. In addition, the obtained results showed that breakthrough curve becomes steeper with decreasing bed height, increasing flow rate and increasing feed concentration. Furthermore break point time is decreased with decreasing bed height, increasing flow rate and increasing inlet oil content. (C) 2012 Elsevier B.V. All rights reserved.