A waste material - coconut husk has been used as a low cost adsorbent and its efficiency in Cyanosine sorption was compared with activated carbon. The influence of various factors such as adsorbent dose, adsorbate concentration, particle size, temperature, contact time and pH was studied. The adsorption of the dye over both the adsorbents was found to follow Langmuir and Freundlich adsorption isotherm models. Based on these models, different useful thermodynamic parameters have been evaluated. The adsorption of Cyanosine over activated carbon and activated coconut husks follows first order kinetics and the rate constants for the adsorption processes increase with temperature in the case of AC and decrease in the case of ACH. (C) 2010 Elsevier Inc. All rights reserved.