Extraction of lanthanide ions from acidic and strongly acidic media by phosphine oxide derivatives using temperature-induced phase separation

Abstract

A composite for the extraction of lanthanide ions from strongly acidic media by temperature-induced phase separation was designed based on the nonionic surfactant Triton X-100 and new phosphine oxide derivatives. The dependence of the efficiency and selectivity of micellar extraction on the length of the hydrophobic substituent at the P=O group is determined by both the influence of hydrophobic substituents on the electron-donor capacity of the P=O group and the solubility of phosphine oxides in aqueous and micellar phases. The nitric acid concentration was found to influence the efficiency of extraction of lanthanide ions by phosphine oxides with different structures. An increase in the concentration of nitric acid in an aqueous medium from 0.1 to 1 mol L−1 leads to a decrease in the degree of extraction by water-soluble derivatives and a substantial increase in the degree of extraction by phosphine oxides, which are soluble only in the micellar phase of Triton X-100.