Poly(amidoxime)-graft-magnetic chitosan for highly efficient and selective uranium extraction from seawater

Adsorbents with highly efficient and selective recovery performance towards uranium are significantly demanded for the sustainable nuclear power production. Herein, poly(amidoxime)-graft-magnetic chitosan (P(AO)-g-MC) was synthesized through functionalizing magnetic chitosan with polyacrylonitrile followed by amidoximation process. Under magnetic field, P(AO)-g-MC can be separated from the solution in 10 s. Owing to the strong affinity of high-density amidoxime groups towards uranium, P(AO)-g-MC showed remarkable adsorption capacity, rapid kinetics and good regeneration performance in uranium spiked aqueous solution. Notably, the 7-day uranium adsorption capacity of P(AO)-g-MC from natural seawater in column mode was up to 5.14 mg/g, 12 times that of vanadium. The excellent uranium uptake performance over vanadium originated from the strong coordination by N and O in amidoxime groups according to theoretical simulation. The advantages of easy separating and high selectivity make P(AO)-g-MC a very potential uranium adsorbent in natural seawater.