The ability of abundantly available heartwood of Areca catechu to adsorb cadmium(II) ions from aqueous solution has been investigated through batch experiments at room temperature. Various sorption parameters such as contact time, initial concentration of cadmium(II) ion, solution pH and amount of the biomass on the adsorption capacity, were studied. The adsorbent was found to be effective for quantitative removal of cadmium(II) ions in acidic conditions and equilibrium has been achieved in 30 min at pH 6.0. The equilibrium adsorption data were fitted to Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models and the model parameters were evaluated. The kinetic study showed that the pseudo-second-order rate equation better described the biosorption process. The FT-IR spectrum analysis revealed that hydroxyl, carboxyl, amide and amine groups were major cadmium(II) binding groups. (C) 2010 Elsevier B.V. All rights reserved.