Extraction of Cu(II), Fe(III), Ga(III), Ni(II), In(III), Co(II), Zn(II) and Pb(II) with LIX ® 984 dissolved in n-heptane

The solvent extraction of some metal ions with LIX ® 984 dissolved in n-heptane was studied. The extraction order observed as the pH of the aqueous solution increases is Cu(II) > Fe(III) > Ga(III) > Ni(II) > Co(II) > Zn(II) ≈ Pb(II). The experimental data obtained are explained considering hydroxyoxime association and metal complex solvation. Numerical analysis of the data with the LETAGROP-DISTR program suggested the presence of the CuR 2, CuR 22HR, FeR 3, GaR 3, NiR 2, InR 3, CoR 2HR, ZnR 23HR and PbR 2HR species in the organic phase. Complex formation between the metal cations and the buffers used was considered in the calculations. The values of the equilibrium constants for the extraction reactions are reported.