Preparation and characterization of trihydroxamic acid functionalized carbon materials for the removal of Cu(II) ions from aqueous solution

Abstract The main objective of this study is to prepare and characterize two functionalizated carbon materials with enhanced adsorptive properties for Cu(II). Thus, two novel hybrid materials have been prepared by a non-covalent functionalization method based on the adsorption of a pyrimidine-desferrioxamine-B conjugate compound (H 4 L) on two activated carbons, ACs (labelled Merck and F). The adsorption of H 4 L on the ACs is pH-dependent and highly irreversible. This is due to strong π-π interactions between the arene centers of the ACs and the pyrimidine moiety of H 4 L. The textural characterization of the AC/H 4 L hybrids shows large decreases of their surface areas. Thus the values of Merck and F are 1031 and 1426 m 2 /g respectively, while these of Merck/H 4 L and F/H 4 L hybrids are 200 and 322 m 2 /g. An important decrease in the micropore volumes is also found, due to the blockage of narrow porosity produced by the adsorption of H 4 L molecules. The ACs/H 4 L hybrids show larger adsorption capacities for Cu(II) (0.105(4) and 0.13(2) mmol/g, at pH 2.0, and 0.20(3) and 0.242(9) mmol/g, at pH 5.5, for Merck/H 4 L and F/H 4 L, respectively) than those of the ACs (0.024(6) and 0.096(9) mmol/g, at pH 2.0, and 0.10(2) and 0.177(8) mmol/g, at pH 5.5, for Merck and F respectively), which is explained on the basis of the complexing ability of the trihydroxamic acid functions. The desorption of Cu(II) from the ACs/H 4 L/Cu(II) materials in acid solution allows the regeneration of most active sites (78.5% in the case of Merck/H 4 L/Cu(II) and 83.0% in the case of F/H 4 L/Cu(II)).