Purification of enriched isotopes using a multi-step elution process

Abstract

Provided herein are methods for isolating an isotope using cation exchange and a multi-step elution process.

1 . A method of isolating an isotope from a composition comprising the isotope and one or more impurities, the method comprising:
 a) loading the composition into a cation exchange resin, wherein the isotope and impurities having a positive oxidation state bind to the cation exchange resin;   b) passing a dilute acid through the cation exchange resin, thereby eluting impurities having a +1 oxidation state from the cation exchange resin; and   c) eluting the isotope from the cation exchange resin by passing a strong acid through the cation exchange resin, thereby obtaining an isotope solution.   
     
     
         2 . The method of  claim 1 , wherein the isotope has an oxidation state of +3 or greater. 
     
     
         3 . The method of  claim 1 , wherein the isotope is a ytterbium (Yb) isotope or a gadolinium (Gd) isotope. 
     
     
         4 . The method of  claim 3 , wherein the isotope is Yb-176, Gd-152, Gd-155, or Gd-160. 
     
     
         5 . The method of  claim 1 , wherein the one or more impurities comprise sodium ions, and wherein the sodium ions are eluted from the cation exchange resin in step b). 
     
     
         6 . The method of  claim 1 , wherein the dilute acid has a molarity of less than 2M. 
     
     
         7 . The method of  claim 6 , wherein the dilute acid has a molarity of 0.2M to 0.8M. 
     
     
         8 . The method of  claim 6 , wherein the dilute acid has a molarity of about 0.4M. 
     
     
         9 . The method of  claim 6 , wherein the dilute acid is a mineral acid. 
     
     
         10 . The method of  claim 9 , wherein the mineral acid is selected from hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, and hydroiodic acid. 
     
     
         11 . The method of  claim 1 , wherein the strong acid has a molarity of 4M to 8M. 
     
     
         12 . The method of  claim 11 , wherein the strong acid has a molarity of about 6M. 
     
     
         13 . The method of  claim 11 , wherein the strong acid is a mineral acid. 
     
     
         14 . The method of  claim 13 , wherein the mineral acid is selected from hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, hydrofluoric acid, hydrobromic acid, perchloric acid, and hydroiodic acid. 
     
     
         15 . The method of  claim 1 , further comprising precipitating the isotope from the isotope solution or drying and calcinating the isotope solution. 
     
     
         16 . The method of  claim 15 , further comprising heating the precipitated or calcinated isotope, thereby obtaining an isotope oxide. 
     
     
         17 . The method of  claim 16 , further comprising irradiating the isotope oxide. 
     
     
         18 . The method of  claim 1 , wherein prior to performing step a), the isotope is captured on a collection target, and wherein the composition comprising the isotope and the one or more impurities is obtained by dissolving the captured isotope from the collection target using an acid; and/or burning the collection target. 
     
     
         19 . The method of  claim 18 , wherein the collection target comprises a carbon fiber lattice. 
     
     
         20 . The method of  claim 19 , wherein the isotope is captured on the collection target by accelerating ions towards the collection target, applying a magnetic field to the accelerated ions, thereby mass separating the isotope from other ions, and blocking the other ions using a mass-resolving aperture, thereby capturing the isotope on the collection target.