TRANSPORT STUDY OF HAFNIUM(IV) AND ZIRCONIUM(IV) IONS MUTUAL SEPARATION BY USING TRI-N-BUTYL PHOSPHATE XYLENE-BASED SUPPORTED LIQUID MEMBRANES

A Hf transport study through supported liquid membranes has been carried out to determine flux and permeability data for this metal ion. Tri-n-butyl phosphate (TBP)-xylene-based liquid membranes supported in polypropylene hydrophobic microporous film have been used. These data for hafnium and the previous data for zirconium have furnished the Zr to Hf flux ratio (S) as a function of nitric acid and TBP concentrations of the order of 12 in a single stage at room temperature. Optimum conditions for the separation of these two metal ions appear to be 5-6 TBP mol/dm3 HNO3, concentrations less-than-or-equal-to 2.93 mol/dm3, and 10-degrees-C. The value of S from an aqueous solution containing 2.4% Hf with respect to Zr has been found to be > 125 at 10-degrees-C and 1.78 mol/dm3 TBP concentration in the membrane. The technique appears to be feasible for purification of Zr with respect to Hf or vice versa.