Mansonia wood sawdust is applied as a biosorbent for the removal of copper and lead ions from single and binary aqueous solution. The effect of solution pH, electrolyte, metal ion competition and temperature were examined to obtain insight of its application for industrial waste water treatment. The Langmuir isotherm provided a better fit to experimental data for lead ion sorption with a higher monolayer capacity, while copper ion sorption was best described by the Freundlich and BET isotherms. The combined effect of adsorbing one metal ion in the presence of the other metal ion reduced the adsorption capacity of either metal ion. In a binary solution, removal of lead ions in the presence of copper ions followed the Langmuir isotherm model while the removal of copper ions in presence of lead ions followed both the Langmuir and BET isotherm models. (C) 2009 Elsevier Ltd. All rights reserved.