The extraction of manganese (II) and tungsten (VI) from aqueous solution using in chloroform was studied as a function of extractant's concentrations and pH. The results indicate that the degree of extraction of Mn (II) and W (VI) is dependent on the extractant's concentrations by a factor of two (2). This means that two moles of the HBPy ligand anion were complexed by one mole each of the Mn(II) and W (VI) ions, indicating that the extracted species both have metal-ligand mole ratio of 1:2,

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... ce the Mn (II) and W (VI) complexes extracted are of composition, Mn(BPy) 2 and WO 2 (BPy) 2 respectively. The extractant equilibrium constants are log K ex = -0.36 and -0.98 for the Mn(BPy) 2 and WO 2 (BPy) 2 respectively, showing that the HBPy is a more effective extractant for Mn (II) than W (VI). Again, the metals are more quantitatively recovered from the aqueous solution at higher acidity (lower pH). The separation factor for these metals using the reagent is reported and shows that the metals can be separated effectively from their mixtures by proper adjustment of the pH of the medium.