Anion-exchange separation of vanadium and molybdenum in alkaline solutions

Abstract

A method for the separation of vanadium(V) and molybdenum(VI) on ion-exchange resins was investigated in the sodium hydroxide solutions. Distrbution coefficients for these ions with strongly basic anion-exchange resins, DIAION SA # 100 of 1001200 mesh in the hydroxide form, were measured at various concentrations of sodium hydroxide solutions.The both of these ions were adsorbed strongly on the resins below pH 12.0, but on the range from pH 12.0 to 2.0M, the distribution coefficients of vanadium(V) decreased sharply with the increasing of sodium hydroxide concentrations and not adsorbed at 2.0M solution, while that of molybdenum(VI) decreased slowly. On the basis of these results, a following procedure is recommended:The solution which containing 2.0 × 10-3 mmol of vanadium(V) and molybdenum(VI) respectively, was passed through an ion-exchange column, 10 × 110 mm, at the sodium hydroxide concentration below pH 12.0. Both of the ions were adsorbed on the resins. Then the vanadium(V) was eluted quantitatively with 20 ml of 2.0M sodium hydroxide solution and separated, from molybdenum(VI). Finally, the molybdenum(VI) was eluted with 25 ml of 1:1 mixed solution of 1.0 M sodium hydroxide solution and 1.0 M sodium chloride solution.