Synthesis and Characterization of Templated Ion Exchange Resins for the Selective Complexation of Actinide Ions

Murray, George M. ; Uy, O. Manual [e-mail] ; [e-mail]

Johns Hopkins University Applied Physics Lab, Laurel, MD (United States)

关键词: Polymeric Extractant;    Ligand;    Metal Ion;    Actinides;    Synthesis;   

RP-ID  :  DOE/ER/14823
RP-ID  :  FG07-97ER14823
RP-ID  :  781711

美国|英语

来源: UNT Digital Library

【 摘 要 】

The purpose of this research is to develop a polymeric extractant for the selective complexation of uranyl ions (and subsequently other actinyl and actinide ions) from aqueous solutions (lakes, streams, waste tanks and even body fluids). Chemical insights into what makes a good complexation site will be used to synthesize reagents tailor-made for the complexation of uranyl and other actinide ions. These insights, derived from studies of molecular recognition include ion coordination number and geometry, ionic size and ionic shape, as well as ion to ligand thermodynamic affinity. Selectivity for a specific actinide ion will be obtained by providing the polymers with cavities lined with complexing ligands so arranged as to match the charge, coordination number, coordination geometry, and size of the actinide metal ion. These cavity-containing polymers will be produced by using a specific ion (or surrogate) as a template around which monomeric complexing ligands will be polymerized. The complexing ligands will be ones containing functional groups known to form stable complexes with a specific ion and less stable complexes with other cations. Prior investigator's approaches for making templated resins for metal ions have had marginal success. We have extended and amended these methodologies in our work with Pb(II) and uranyl ion, by changing the order of the steps, by the inclusion of sonication, by using higher complex loading, and the selection of functional groups with better complexation constants. This has resulted in significant improvements to selectivity. The unusual shape of the uranyl ion suggests that this approach will result in even greater selectivities than already observed for Pb(II). Preliminary data obtained for uranyl templated polymers shows unprecedented selectivity and has resulted in the first ion selective electrode for uranyl ion.