Metal complex formation on the surface of amorphous aluminium hydroxide part I. Copper (II) complexes of glutamic and aspartic acids

The role of glutamic and aspartic acids in affecting the adsorption of copper (II) onto aluminium hydroxide from aqueous solution has been studied by means of analytical and spectroscopic (ESR and reflectance absorption) measurements. It has been found that the sorption behavior may be accounted for by the interaction of surface-adsorbed ligands with copper (II) in solution to yield complexes, having 1:1 and 1:2 metal to ligand ratios, where the ligands coordinate through the amino and ?-carboxyl groups. At low pH values, the presence of adsorbed ligands significantly enhances the metal sorption over that for the "uncomplexed" ion. However, at high pH values, the ligand excess in solution competes with surface for the metal ion and inhibits Cu (II) uptake. © 1987.