The precursor crystalline alkaline fitanate K2Ti4O9 had the potassium ion-exchanged with an acidic solution to yield H2Ti4O9, which was intercalated with 1,8-octyldiamine inside the interlayer nanospace to give Oct-H2Ti4O9. These three matrices were exchanged with divalent cobalt, nickel and copper cations at the solid/liquid interface and it was verified that as a general behavior, the matrix K2Ti4O9 have the highest ion-exchange capacity towards the chosen metallic cations, when compared with the other matrices. The carbon and hydrogen elemental analyses demonstrated a decrease in the amount of diamine after ion exchange process, reflecting the successive displacement of the inserted organic molecule in the inorganic matrix with the progress of the exchanging reaction. The amount of divalent cations exchanged for those three matrices follow the order: Cu > Co > Ni. (c) 2005 Elsevier Ltd. All rights reserved.