| The presence of plutonium in waste streams and in nature necessitates the development of technologies for the removal of a small amount of plutonium from a large volume of solvent. The prevalence of the Pu(IV) oxidation state and its similarity to Fe(III) has led to the synthesis of Pu(IV) chelating agents based on naturally-occurring Fe(III) sequestering agents (siderophores). The Th(IV) and Pu(IV) chelation ability of three derivatives of the siderophore Desferrioxamine B (DFO), DFOMTA, DFOCAMC, and DFO-1,2-HOPO has been studied. The formation constants and metal/ligand protonation constants are presented. The potential use of these materials as Pu(IV) sequestering agents is discussed. The Th(IV) and Fe(III) chelation ability of three bidentate binding units that are similar to naturally-occurring binding groups has been studied. The protonation constants and the metal/ligand protonation constants for the three ligands, MTA, N-Propyl-1,2-HOPO, and N-Propyl-3,4-HOPO, are presented. The potential for using these ligands as solid/liquid extractants is discussed.; The attachment of siderophore or siderophore-like binding groups to solid-supports is presented. The structure and metal uptake abilities of these materials is presented. The potential of these materials as solid/liquid extractants is discussed. Attempts to increase the loading capacity and hydrophilicity of solid-support chelating groups is presented. The structure and Th(IV) uptake ability of these materials is discussed and compared to the first generation of solid-supported ligands. The potential of these materials as solid/liquid extractants is discussed along with the direction future investigations in this area should head. |
