Preparation of amidoxime-based PE/PP fibers for extraction of uranium from aqueous solution

A novel amidoxime-based fibrous adsorbent, denoted as PE/PP -g- (PAAc -co- PAO), was prepared by pre-irradiation grafting of acrylic acid and acrylonitrile onto polyethylene-coated polypropylene skin–core (PE/PP) fibers using 60 Co γ-ray irradiation, followed by amidoximation. The original and modified PE/PP fibers were characterized by a series of characterization methods to demonstrate the attachment of amidoxime groups onto the PE/PP fibers. Breaking strength tests confirmed that the fibrous adsorbent could maintain good mechanical properties. The adsorption capacity of the PE/PP -g- (PAAc -co- PAO) fibers was investigated in simulated seawater with an initial uranium concentration of 330 μg/L. The uranium adsorption capacity was 2.27 mg/g-adsorbent after 24 h in simulated seawater, and the equilibrium data were well described by the Freundlich isotherm model. The PE/PP -g- (PAAc -co- PAO) adsorbent exhibited good regeneration and recyclability during five adsorption–desorption cycles. The adsorption test was also performed in simulated radioactive effluents with uranium concentrations of 10 and 100 μg/L. The effect of the pH value on the adsorption capacity was also studied. At a very low initial concentration 10 μg/L solution, the PE/PP -g- (PAAc -co- PAO) fiber could remove as much as 93.0% of the uranium, and up to 71.2% of the uranium in the simulated radioactive effluent. These results indicated that the PE/PP -g- (PAAc -co- PAO) adsorbent could be used in radioactive effluents over a wide range of pH values. Therefore, the PE/PP -g- (PAAc -co- PAO) fibers, with their high uranium selectivity, good regeneration and recyclability, good mechanical properties, and low cost, are promising adsorbents for extracting uranium from aqueous solutions.