Effect of the Concentration of Metal Ions on their Adsorption on Various Hydrous Iron and Aluminum Oxides.

Abstract

The adsorption of Eu(III) and Co(II) on laboratory-prepared amorphous hydrous iron and aluminum oxides, goethite and gibbsite, was studied as a function of pH over a wide range of metal ion concentrations, in order to see the effect of the change in the degree of site occupation by metal ions. When the metal ion concentrations were low, a simple Langmuir equation with a single adsorption constant was able to describe adsorption on these hydrous oxides. At high metal ion concentrations, adsorption on goethite and gibbsite exhibited clear saturation maxima expected from a simple one-to-one interaction between the metal ion and the adsorption site, while adsorption on laboratory-prepared hydrous oxides continued to increase gradually even at high metal ion concentrations.