Sorption of microamounts of Ce3+, Pm3+, Eu3+, Gd3+ and Yb3+ on aluminium hydroxide

The sorption of microamounts of trivalent lanthanides (Ln³⁺) on freshly precipitated Al(OH)₃ has been measured in dependence on pH and the time of sorption. Also, the influence of organic complexing ligands and inorganic electrolytes on the sorption process has been investigated. The mechanism of sorption is discussed. Freshly precipitated Al(OH)₃ can be used for the preconcentration of microamounts of trivalent lanthanides. However, the preconcentration is not quantitative in the presence of high concentrations of complexing ligands (citrate and similar) which form strong complexes with Ln³⁺ ions.