Synergistic extraction of Ce(III), Eu(III) and Tm(III) with a mixture of picrolonic acid and tributylphosphine oxide in chloroform

Synergistic extraction of Ce(III), Eu(III) and Tm(III) as a representative of lanthanides(III) with a mixture of picrolonic acid {1-p-nitrophenyl-3-methyl-4-nitro-5-pyrazolon (HPA)} acting as an acidic chelating agent and tributylphosphineoxide (TBPO) as a neutral ligand in chloroform from pH 2 buffer solution has been studied. The composition of the synergistic adduct has been determined to be M(PA)(3)(.)2TBPO (M=Ce(III), Eu(III), Tm(III)). The effect of various anions and cations on the extraction of these metal ions has also been studied. Among the anions, fluoride, oxalate, citrate and cyanide ions masked the extraction, whereas Fe(III) and Cu(II) reduced the extraction to similar to90%. The formation constant, and separation factor from various metal ions has also been determined and discussed.