In this paper, a novel adsorption material PEI/SiO2 with strong adsorption ability towards heavy-metal ions was prepared. In preparation of PEI/SiO2, functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles via the coupling effect of gamma-chloropropyl trimethoxysilane (CP). The adsorption properties of PEI/SiO2 for Pb2+ ion were studied by both static and dynamic methods. The experimental results show that PEI/SiO2 possesses very strong adsorption ability for Pb2+ ion, the saturated adsorption amount could reach to 17.5 mg g(-1), and the empirical Langmuir isotherm was found to describe well the equilibrium adsorption data. The pH and grafting amount of PEI have great influence on the adsorption amount. The Pb2+ ions adsorbed on PEI/SiO2 are eluted easily by diluted hydrochloric acid solution. (c) 2006 Elsevier B.V. All rights reserved.