Chelating Polymers for Recovery of Uranium from Seawater∗

Binding of uranyl ion by 2,2′-dihydroxyazobenzene attached to crosslinked polystyrenes covered with highly populated quaternary ammonium cations

“…Seawater contains about 0.55 M NaCl and 2.5 mM bicarbonate ion; its pH is 7.8 to 8.2. 6 Examples of well-studied ligands of uranyl ion are carboxylates 3,7,8 such as EDTA analogues, 9,10 phenols, 3,11 amidoximes, 12 and ␤-ketones. 2,13 In particular, efforts have been directed toward selective molecular recognition of uranyl ion with macrocyclic host molecules including crown ethers and calixarenes.…”

The urgency of the development of CO 2 capture from ambient air

“…Applying the same logic to the extraction of uranium from seawater would suggest that such efforts could not possibly succeed, considering the fact that the concentration of uranium in seawater is about 3 parts per billion. However, there have been largely successful efforts both at Massachusetts Institute of Technology (Cambridge, MA) and in Japan (59)(60)(61).…”

Recent International R&D Activities in the Extraction of Uranium from Seawater

“…Both laboratory studies and marine experiments in the Pacific Ocean have been conducted. The laboratory studies cover the preparation of amidoxime-based adsorbents, the equilibrium of the uranium uptake, and the kinetics and mechanism of the extraction of uranium from seawater (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). Collection of uranium with chitosan-resin and biomass such as algae was also performed (17,18).…”