ION AND LITHIUM ISOTOPE SELECTIVITIES OF SORBENTS PREPARED FROM MG2MNO4

A lithium-specific sorbent, HMnO(2Mg), has been prepared by extracting magnesium ions from Mg2MnO4 through ion exchange with hydrogen ions, and its ion and lithium isotope selectivities have been studied as fun ctions of the degree of magnesium extraction, DE(Mg). The properties a s a specific-lithium sorbent revealed itself for the sorbents with a D E(Mg) value of over 50%. The maximum distribution coefficient for the lithium ion and the maximum lithium uptake from a 0.1 M LiOH solution were 14900 cm(3) g(-1) and 2.26 mmol g(-1) respectively, at DE(Mg) = 9 7% at 25 degrees C. Isotopically, HMnO(2Mg) was a Li-6-specific sorben t like other inorganic sorbents and organic ion exchangers so far inve stigated. The Li-7-to-Li-6 isotopic separation factor varied between 1 .006 and 1.016 at 25 degrees C as a function of DE(Mg). High Li-6 sele ctivity was observed when HMnO(2Mg) did not show properties as a lithi um-specific sorbent.