Separation of lanthanum(III), gadolinium(III) and ytterbium(III) from sulfuric acid solutions by using a polymer inclusion membrane

Abstract

This study demonstrates for the first time the possibility of selective separation of heavy, middle and light lanthanide ions, represented by Yb(III), Gd(III) and La(III), using a polymer inclusion membrane (PIM) composed of 45 wt% di-(2-ethylhexyl) phosphoric acid (D2EHPA) and 55 wt% poly(vinyl chloride) (PVC). Complete and selective extraction of these three lanthanide ions was achieved by varying the pH of the sulfuric acid feed solution (i.e. Yb(III) at pH 0.25, Gd(III) at pH 1.25 and La(III) at pH 2.25). The extracted ions were back-extracted completely into solutions containing sulfuric acid at concentrations of 7.0, 1.0 and 0.3 mol L−1, respectively. A comprehensive study of the Yb(II..