Abstract
Ion exchange is well known as an excellent technique for chemical separation and applicable even for separation of isotopes. The present paper describes the principle of isotope effects in chemical exchange equilibrium, and the application to the separation of isotopes by using ion exchange resins. Separation coefficients and height equivalent to a theoretical plate have been determined for the experimental systems at different conditions. In particular, flow rate dependence of HETP has been studied on 15N enrichment processes. The study has been extended to the isotope effects of more heavier elements, such as transition elements, lanthanoid and uranium. The isotope effects in complex formation of transition elements have shown to be relatively smaller than those of electron exchange reactions observed by redox chromatography using anion exchange resin. The strange isotope effects observed for U (IV) -U (VI) electron exchange reaction has been elucidated as the isotope effects due to the electron-nuclear interactions.
