Amidoximated polyethylene nonwoven fabric used for highly efficient recovery of uranyl carbonate from alkaline solution with high concentration of fluoride ions

Highlights: • An appropriate feed volume ratio of AN (60) to MAA (40) achieved high U adsorption performance. • The AO based PE nonwoven fabrics presented both high U adsorption capacity and excellent F⁻ ion tolerance. • The AO based PE nonwoven fabrics could be easily regenerated, and exhibited excellent reusability. • The amino (NH₂) and hydroxyl (OH) moieties from AO groups, not the carboxyl groups, coordinate with uranyl ions. Herein, an amidoxime-based polyethylene nonwoven fabrics sorbent was fabricated to efficiently extract uranyl carbonate from an aqueous solution containing high concentration of fluoride ions. The fabrication process involved radiation co-grafting of acrylonitrile and methacrylic acid, followed by amidoximation and potassium hydroxide treatment. X-ray photoelectron spectroscopy confirmed that the uranium (U) with a atomic content of 0.25% was adsorbed on the sorbent. The batch experimental results indicated that U adsorption kinetics and isotherm were compliant with the pseudo-second-order model and the Freundlich model, respectively. The maximum U adsorption capacity was 126.7 mg/g (initial U concentration: 40.0 mg/L; sodium fluoride: 10.0 g/L; sorbent dosage: 0.2 g/L; time: 42 d), which is close to the predicted value of 138.7 mg/g. In addition, the residual U concentration effectively reduced from 0.1 mg/L to 3.2 μg/L and from 40.0 mg/L to 17.0 μg/L at different sorbent dosage. Moreover, the nonwoven fabric sorbent exhibited excellent fluoride ion tolerance and good reusability.