Branched fibrous amidoxime adsorbent with ultrafast adsorption rate and high amidoxime utilization for uranium extraction from seawater

Direct collection of uranium from low uranium systems via adsorption remains challenging. Fibrous sorbent materials with amidoxime (AO) groups are promising adsorbents for uranium extraction from seawater. However, low AO adsorption group utilization remains an issue. We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven (PP/PE SNW) fibers using grafting polymerization induced by radiation (RIGP) to improve AO utilization. The chemical structures, thermal properties, and surface morphologies of the raw and treated PP/PE SNW fibers were studied. The results show that an adsorptive functional layer with a branching structure was successfully anchored to the fiber surface. The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500 μg·L −1 (pH 4, 25 °C). The maximum adsorption capacity of the adsorbent material was 137.3 mg·g −1 within 24 h; moreover, the uranyl removal reached 96% within 240 min. The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 4–10, with good selectivity and reusability, demonstrating its potential for seawater uranium extraction.