Liquid Membrane Transport of Heavier Rare Earth Metal Ions Based on CPC Results with Di(2-Ethylhexyl) Phosphoric Acid

Abstract

The behaviors of heavier rare earth metal ions in bulk liquid membrane transport systems were examined for Gd³⁺, Tb³⁺, Dy³, Ho³⁺, Er³⁺, Tm³, Yb³⁺ and Lu³⁺ ions. The liquid membrane transport system was constructed by aq. HCl/CHCl₃ containing Di (2-ethylhexyl) phosphoric acid/aq. HCl. The optimum concentration of HCl in the aqueous phase with respect to the rate of transport for these ions increased with the atomic number of the rare earth elements. This trend of transport behaviors was on the same line observed for lighter rare earth ions in the preceding work. Difference in the rate of transport can be used for selective liquid membrane transport of several sets of combination with these ions.