The present paper is aimed to investigate and develop cheap adsorption methods for colour removal from wastewater using waste material de-oiled mustard as adsorbent. De-oiled mustard, a biosorbent, was successfully utilized for removing a water-soluble xanthene dye, Erythrosine from wastewater. Kinetic studies of adsorption of Erythrosine at de-oiled mustard were carried out at 30 degrees C, using aqueous solutions with 5 x 10(-5) M concentration of Erythrosine. The adsorption process followed a pseudo-first order model. The equilibrium process can be well described by both Freundlich and Langmuir models, at 30, 40 and 50 degrees C. Free energy of adsorption (Delta G degrees), enthalpy (Delta H degrees), and entropy (Delta S degrees) changes were calculated to predict the nature of adsorption. The estimated values for Delta G degrees were -12.81 x 10(3) and -12.57 x 10(3) over activated carbon and activated de-oiled mustard at 203 K (30,C), indicate toward a spontaneous process. The positive value for Delta H degrees indicates that the adsorption of Erythrosine dye to de-oiled mustard is an endothermic process. (c) 2008 Published by Elsevier B.V.