High surface area silicas are used as adsorbents, often desiccants, in numerous applications. These silicas can also be functionalized for a variety of uses ranging from catalysts to composites. In this work these materials have been functionalized to study the adsorption of metal ions from aqueous solution, as a potential means to clean up polluted waters. Two silica gels, and one nanoparticulate, nonporous fumed silica, were studied. The silica gels differ in their pore radius and distribution to determine the textural effects on adsorption behavior. The role of functional group on the extent of adsorption was studied primarily for amino functionalized surfaces. Surface modified mono- di- and triaminofunctionlized surfaces were synthesized, characterized and studied for their adsorption behavior. Metal ion adsorption isotherms from aqueous solution were obtained from atomic absorption measurements of residual solution phase metal as a function of concentration. Adsorption capacities and free energy distribution functions were calculated from the isotherms. Results suggest that adsorption capacities can be considerably increased by reacting high surface area silicas with organosilanes containing a large number of complexing functional groups. Adsorption capacity is also enhanced when using a silica gel with a large pore diameter. On the other hand adsorption free energy can be decreased using a silica gel with a smaller pore diameter. These results suggest ways to improve the behavior of surface modified silicas for enhanced adsorption of metal ions from aqueous solution.