Silesquioxane 3-n-propylpyridiniumchloride polymer (abbreviated as SiPyCl), was used to coat SiO2/Al2O3 substrate surface to form the chemically modified solid SiO2/Al2O3/SiPyCl having the specific surface area S-BET = 233 m(2) g(-1). The resulting polymer film was strongly adhered to the surface by means of =Al-O-Si bonding (where =Al stands for Al2O3 grafted on SiO2 surface) and presented an ion exchange capacity of 1.04 mmol g(-1). The metal halides, MCz [M = Fe(III), Cu(II) and Zn(II)], were adsorbed by the modified solid from ethanol solutions as neutral species by forming the surface anionic complexes described by the equation: mSiO(2)/Al2O3/SiPyCl + MClz reversible arrow (SiO2/Al2O3/SiPy (1))(m)[MClz+m](m-), where FeCl4-, ZnCl42- have tetrahedral and CuCl42- distorted tetrahedral symmetries. The equilibrium coefficients, K, determined for each complex species showed that SiO2/Al2O3/SiPyCl + has a high affinity for the metal ions. The following values expressed as log K were found: Cu = 3.0, Zn = 3.5 and Fe = 3.0. The material could efficiently preconcentrate these metal ions from an ethanol solutions and release them in aqueous solution. (C) 2001 Elsevier Science B.V. All rights reserved.