Effect of valence state on chromatographic fractionation of molybdenum isotope in aqueous hydrochloric acid solutions

The Mo(V) and Mo(VI) isotope fractionation using typical anion-exchange resins was investigated in 0.10 M (M = mol / dm3) HCl solutions at 308 and 338 K. The examined resins were benzimidazole-type anion-exchange resin embedded in high-porous silica beads, which has two types of functional groups consisting of 1-methylbenzimidazole and 1,3-dimethylbenzimidazole (AR-01(Cl form)), weakly basic porous-type WA20 resin (WA20(Cl form)), and PA316 resin, which is one of porous-type strongly basic anion-exchange resin (PA316(Cl form)). As a result, the isotope separation coefficients of Mo(VI) species were obtained by using the isotope fractionation curve of Mo(VI) species with AR-01(Cl form) and WA20(Cl form) resins while we couldn't observe the Mo(VI) isotope fractionation in case of PA316 resin and the Mo(V) isotope fractionation using these resins. It may be suggested that these tendencies for the Mo isotope fractionation are caused by the weak adsorption of Mo(VI) species onto PA316 resin and the strong adsorption of Sn species used for reduction of Mo(VI) species for these resins.