Mixed ligand complexation in the extraction of Dy(III) and Sm(III) with the HTTA-TBA synergic system

Abstract

Synergic extraction of hydrolyzable lanthanides Dy(III) and Sm(III) has been studied in the low pH range with 0.3M (HTTA-TBA) in chloroform from aqueous perchlorate media. The synergic coefficient was calculated at different pH's and was found maximum at pH 3 for both elements. The composition of the adduct was established as M(TTA)3.3TBA at pH 3. However, a mixture of the adduct of the type M(TTA)3.TBA was proposed at pH 5.9. The possible reaction mechanism at both pHs is discussed, the stability constant βm,n′ formation constants Km,o and Km,n have been calculated.