Fully Chelating N<sub>3</sub>O<sub>2</sub>-Pentadentate Planar Ligands Designed for the Strongest and Selective Capture of Uranium from Seawater
Takumi Mizumachi, Minami Sato, Masashi Kaneko, Tomoyuki Takeyama, Satoru Tsushima, Koichiro Takao
Abstract
Based on the unique fivefold equatorial coordination of UO22+, water-compatible pentadentate planar ligands, H2saldian and its derivatives, were designed for the strong and selective capture of UO22+ in seawater. In the simulated seawater condition (0.5 M NaCl + 2.3 mM HCO3–/CO32–, pH 8), saldian2– shows the strongest complexation with UO22+ to form UO2(saldian) (log β11 = 28.05 ± 0.07), which is more than 10 order of magnitude greater than amidoxime-based or -inspired ligand systems most commonly employed for U capture from seawater. Good selectivity for UO22+ from other metal ions coexisting in seawater was also demonstrated.
Topics & Concepts
SeawaterChemistryUraniumLigand (biochemistry)ChelationInorganic chemistrySelectivityMetalMetal ions in aqueous solutionIonUranylArtificial seawaterOrganic chemistryCatalysisMetallurgyOceanographyReceptorMaterials scienceBiochemistryGeologyRadioactive element chemistry and processingChemical Synthesis and CharacterizationExtraction and Separation Processes