Bagasse from sugarcane, a waste material, has been studied as a biosorbent for removing lead from aqueous solutions in batch systems. In this study. bagasse was modified by sulphuric acid to enhance sorption capacity for lead and the origin of the enhancement was investigated by observing the change in surface functional group concentrations and the lead sorption behaviours. The untreated and treated bagasse was characterized by elemental analysis, SEM, FTIR and potentiometric titrations. Titrations revealed two different types of sites present on both solid wastes that probably correspond to carboxyl and amine groups. Sorption isotherm test showed that equilibrium sorption data were better represented by Langmuir model than the Freundlich model. The sorption capacities for lead of untreated bagasse and bagasse treated by H2SO4 were 6.366 and 7.297 mg/g, respectively at 25 degrees C and pH 5. (C) 2010 Elsevier B.V. All rights reserved.