Eu(III) extraction by bis(2-ethylhexyl)phosphoric acid and 8-hydroxyquinoline in dodecane from perchlorate medium

Europium(III) was extracted by bis(2-ethylhexyl)phosphoric acid (HDEHP) and 8-hydroxyquinoline (HQ) in dodecane from aqueous perchlorate media of constant ionic strength (0.1M; H⁺, NaClO₄). Slope analysis of the data indicate that three molecules of HDEHP or HQ are attached to Eu³⁺. Extraction constants were obtained at different temperatures. The data were used to calculate the thermodynamic parameters (G, H and S) for the extraction process in the two systems. When using mixtures of crown ethers with HDEHP no synergism was observed.