Covalent modification of ZIF-90 for uranium adsorption from seawater

Uranium is one of the main crude materials for nuclear reaction, but the total uranium content on land is far from meeting the long-term needs of nuclear energy for the human being. How to enrich uranium from seawater with high reserves but extremely low uranium concentration and a great quantity of competitive ions has become a key project. In this work, we report the synthesis of aminooxime functionalized ZIF-90 by grafting 4-aminobenzamidoxime, named ZIF-90-ABOA, which exhibits outstanding adsorption performance benefitting from the high chelating ability of amidoxime towards uranium. The maximum adsorption capacity of uranium is 353.4 mg g−1 from aqueous solution, which is much higher than the original ZIF-90. Additionally, the adsorption capacity can reach 2.8 mg g−1 in 7 days from natural seawater, proving the potential enrichment of uranium in real application.