This study investigated the potential use of ethylenediamine functionalized SBA-15 (en-SBA) nanoporous silica compound, in removal and preconcentration of lead and cadmium cations from aqueous solutions. en-SBA was synthesized according to procedure in the literature and the presence of organic groups in the silica framework was demonstrated by FTIR spectrum. The functionalized product showed the BET surface area 250 m(2) g(-1) and pore diameter 27 angstrom. based on adsorption-desorption of N-2 at 77 degrees K. Flame atomic absorption spectrometry was used to determine the ions concentration in the eluted solution after the adsorption process. The effect of several variables such as (amount of adsorbent, stirring time, pH, metal concentration and presence of other metals in the medium) has been studied. Lead and cadmium ions were completely removed at pH greater than 4.5 after stirring for 15 min. The maximum capacity of the adsorbent was found to be 360.0 +/- 1.4 mu g and 100.0 +/- 0.6 mu g of lead and cadmium ions/mg functionalized SBA-15, respectively. The preconcentration factor of the method was found to be 200. The applications of this methodology for real samples were examined by laboratory wastewater samples. For all samples the percentage of removal and recovery was found to be more than 98%. (C) 2010 Elsevier B.V. All rights reserved.