Strontium isotope effect on Solid-Liquid extraction system using a polymer resin with 2.2.2-Cryptand anchor groups

The chemical isotope exchange with macrocyclic polyethers is one of the relatively new methods for isotope separation. These separations are based on the phenomenon of isotope effect, in which the kinetic and the stability of the complex formation between the ligand and the isotopes of an element are different. In particular, crown ethers and cryptands, with high affinity and size selectivity for some metal ions, have been investigated for isotope separation in various extraction processes. In the present study, the isotope effect in a solid-liquid extraction of strontium with Merrifield resin having 2.2.2-Cryptand anchor groups was investigated. The effects of various experimental parameters such as pH, concentration of strontium, type of anion, equilibrium time, and temperature on the separation factor of strontium isotopes were studied and discussed. The results showed that the separation factor had an inverse correlation with the isotope mass and for the lighter isotopes this factor was greater. Under the optimum conditions, the separation factors for 84Sr/88Sr, 86Sr/88Sr, and 87Sr/88Sr were 1.028, 1.017, and 1.014, respectively.