The organosilane-modified Saharan kaolin (KS) was prepared and tested as an adsorbent for Cu(II), Ni(II), Co(II) and Cd(II) removal from aqueous solution in comparison with original Saharan kaolin (K). Characterization of modified clay material and original clay was carried out by different methods (XRD, FTIR, TGA and SEM) in order to establish the link between synthesis, structures and properties. The hydrophilic properties of the clay surface have been modified, but not turned into hydrophobic ones. The graft has indeed a polar amine group and the chain length is too short to present an important hydrophobic character. The adsorption of heavy metal ions onto APTES-modified kaolin showed greater efficiency than original kaolin. The adsorption of metal ions by the original kaolin is dominated by the cation exchange phenomenon with a preferential order of selectivity: Cu(II)>Ni(II)>Co(II)>Cd(II), while adsorption on KS is mainly dominated by attraction of the chelating group of the amine in the same order of selectivity. This new hybrid organic-inorganic material may be a good alternative for separation and preconcentration of heavy metal ions.