The effects of bi-metal extractions on separation factors using 4, 4´-(1e, 1e´)-1, 1´-(ethane-1, 2-diylbis (azan-1-yl-1ylidene)) bis (5-methyl-2-phenyl-2, 3-dihydro-1h-pyrazol-3-ol)

Abstract

The effect of the presence of a second metal on the theoretically calculated Separation Factors βTXY from distribution ratios obtained in the metal alone extractions from aqueous solutions buffered to either pH 4.75 or 7.5 containing 0.001 M and 0.005 M of either H3PO4 or H2SO4 using the Schiff base ligand 4,4´-(1E,1E´)-1,1´-(ethane-1,2-diylbis(azan-1-yl-1ylidene))bis(5-methyl-2-phenyl-2,3-dihydro-1H-pyrazol-3-ol) (H2BuEtP) alone and 0.1 M Oxalate ion using a mixed ligands H2BuEtP-HBuP in 9:1 volume ratio was studied by comparing with Separation Factors βEXY obtained from distribution ratios from bimetal extractions of a pair of metals from Cadmium, Iron, Nickel and Lead under same aqueous media condition using same organic phases. 60 minutes equilibration time was used and 2 batches of extractions were done based on calculated n batches of extractions needed to obtain 99.9% extraction of Cadmium which had the highest distribution ratios in the metals alone extractions. The aqueous raffinates were analysed using colorimetric method for iron with 1, 10-phenanthroline and the other metals with atomic absorbance spectrophotometer and distribution ratios calculated by difference. All the metals that were masked in their metal alone extraction were all extracted above 82% with all distribution ratios in the bimetal extractions statistically significantly different from those obtained in the metal alone extractions resulting in experimental Separation Factors βEXY all < 5. The results indicated that the ligand H2BuEtP has more potentials for multimetal extraction than in the separation of Cadmium from Iron, Nickel and Lead. pH 7.5 bimetal extraction results were far better than those for pH 4.75 and it was recommended that multimetal extractions with other metals be studied with the ligand H2BuEtP.