Separation of vanadium isotopes by ion-exchange chromatography

Cation-exchange displacement chromatography of VO2+ was carried out for studying vanadium isotope effects in carboxylate ligand-exchange systems. The heavier isotope V-51 was enriched in the carboxylate complex solution. The isotope separation coefficients epsilon(=alpha-1) for V-50/V-51 were 2.2.10(-4) and 2.4.10(-4) for citrate and lactate systems at 298 K, respectively. These values are much larger than those obtained in a previous study on the malate system. The existence of binuclear complexes of VO2+ may create the conditions for larger isotope fractionation. From the viewpoint of the process development of isotope separation, the heights equivalent to a theoretical plate of these processes were analyzed and found to be very small in each system due to the homogeneous, small and highly porous resin used. Citrate may be better than the other tested systems for the vanadium isotope separation. (C) 2002 Elsevier Science B.V. All rights reserved.