A novel anti-biofouling collagen fiber grafted with hyperbranched polyethyleneimine/amidoxime for efficient uranium extraction from seawater

Uranium is the basic ingredient for nuclear energy production, but its terrestrial resources are limited. The efficient extraction of uranium from natural seawater can greatly alleviate the current shortage of uranium resources. Herein, biomass material collagen fibers (CFs) were grafted by hyperbranched polyethyleneimine (HPEI) and amidoxime (AO) groups, and a novel anti-fouling uranium extraction adsorbent (CFs-PEI-AO) was successfully prepared by the chemical cross-linking method. The construction of molecular-level uranyl-specific nano-pocket through hydrogen-bond interaction between amino and amidoxime groups provided efficient extraction and ultra-high selectivity to uranium. This fibrous adsorbent displayed a remarkable uranium adsorption capacity of 561.80 mg g⁻¹, with a notable K_d value (4.57 × 10⁵ mL g⁻¹) in co-existing ions solution. In addition, the Schiff base structure formed by the chemical cross-linking process endowed CFs-PEI-AO with excellent reusability and effective anti-biofouling activity. In the fixed-bed adsorption system, CFs-PEI-AO achieved a total uranium capture capacity of 1.042 mg g⁻¹ after continuously flowing 30 L natural seawater for 15 days, and an impressive uranium removal ratio of 97.4 %, making it a promising candidate for uranium extraction from natural seawater.