Alumina surface was modified by adsorption of an anionic surfactant, sodium dodecyl sulfate (SDS). Typical S-shaped isotherm of surfactant on alumina was observed. The adsorption of herbicide on alumina and surfactant treated alumina has been investigated. The enhancement in adsorption of herbicide on surfactant treated alumina is observed, which may be attributed to the solubilization of herbicide on surfactant aggregates formed at solid/liquid interface. The effect of pH on adsorption has been studied. The adsorption is greatly influenced by pH of the medium. The applicability of Freundlich equation was tested for equilibrium data. The influence of various factors such as initial concentration, agitation speed, mass of adsorbent and temperature on adsorption was also studied. The batch kinetics has been tested to pseudo second order reaction and rate constants were calculated. (C) 2004 Elsevier B.V. All rights reserved.