Ion Exchange of Lanthanides with Conventional and Ion-Imprinted Resins Containing Sulfonic or Iminodiacetic Acid Groups

Ion exchange equilibria of samarium, dysprosium, and erbium were measured in conventional and ion-imprinted resins containing sulfonic acid groups or iminodiacetic acid (ida) groups in H,H-form and partially neutralized H,Na-form. The ion-imprinted resins were prepared by copolymerization of complexes prepared from Er3+. Conventional resins have low selectivity because electrostatic interactions are dominant even for the ida resin. In ion imprinting, the complex structure formed a priori in bulk solution was retained in the resin and coordinative interactions became more prominent. As a result, the selectivity coefficient K-Sm(Er) increased from 1.0 of the conventional resin to 3.5 of the imprinted resin.