Quaternized and Hyperbranched Amidoxime-Modified Ultra-High-Molecular-Weight Polyethylene Fiber for Uranium Extraction from Seawater

The most promising material for uranium extraction from saltwater is generally acknowledged to be fibrous adsorbents. An irradiation-modified anti-biofouling ultra-high-molecular-weight polyethylene (UHMWPE-<i>g</i>-PGAO) fibrous adsorbent with a hyperbranched structure was synthesized. It exhibited adsorption capacities of 314.8 mg-U/g-Ads in aqueous solution and 4.04 mg-U/g-Ads in simulated seawater over a 28-day period. The ultra-high-molecular-weight polyethylene (UHMWPE) fiber was functionalized by covalently linking hyperbranched polyethyleneimine (h-PEI) to facilitate the migration of uranyl ions within the fibers. Additionally, amidoxime and quaternary ammonium groups were immobilized on the fiber surface to enhance uranium affinity and provide defense against marine organisms. This three-dimensional design of amidoxime and h-PEI-modified UHMWPE fiber retained more than 91.0% of its maximum adsorption capacity after undergoing five adsorption-desorption cycles. The UHMWPE-<i>g</i>-PGAO adsorbent exhibits significant antibacterial activity against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, achieving an inactivation efficiency of over 99.9%. It is proved to be an innovative fiber adsorbent for uranium extraction from seawater for its biofouling resistance, robustness, and reusability.