The adsorption of rhodamine B dye was carried out using sodium montmorillonite clay. The effect of parameters such as pH, adsorbent dosage and initial dye concentration was studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best fit the equilibrium isotherm data. Langmuir adsorption capacity was found to be 42.19 mg/g. Kinetic data followed pseudo-second-order kinetics. Maximum color removal was observed at pH 7.0. The Delta G degrees value was found to be negative, the adsorption process was feasible. The results indicate that sodium montmorillonite clay can be used for the removal of basic dyes from aqueous solutions. (c) 2007 Elsevier B.v. All rights reserved.