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[Display omitted] • Functionalized electrospun nanofibers were applied for the uranium extraction. • Hyperbranched amidoxime groups with assistant groups were grafted. • Photothermal conversion ability was also introduced into the fibers. • The nanofiber adsorbents showed good antibacterial activity. • The uranium extraction capacity reached 9.54 mg g−1 from natural seawater. Uranium extraction from natural seawater is critical to addressing the shortage of uranium resources, but it is a giant challenge. The amidoxime-based adsorbent is regarded as one of the most promising materials for uranium capture, whereas still suffers from low adsorption site utilization and poor selectivity toward U(VI) against V(V). Herein, hyperbranched amidoxime group grafted photothermal electrospun fibers (AOPEI-C-PAN fibers) were reported for highly efficient uranium extraction from seawater. Carbon nanotubes (CNTs) were blended into the electrospun fibers to introduce the photothermal character. Hyperbranched grafting could improve the content of the amidoxime group and bring an assistant group (the amine group). Owing to the large content of functional groups, synergetic coordination interaction and photothermal conversion ability, the novel fiber adsorbents realized a fast adsorption rate (shortening the equilibrium time to 36 h from 60 h compared with the dark condition), high uranium uptake (1738.5 mg g−1 from the Langmuir model) from the uranium spiked seawater and excellent selectivity in U/V binary system (selectivity coefficient = 85.8). Furthermore, Ag nanoparticles could also be loaded onto the CNTs to endow the fibers with antibacterial activity, thereby preventing biofouling. As a result, the uranium extraction capacity of the fiber adsorbent reached 9.54 mg g−1 after 28 days' simulated sunlight irradiation of contact with circular seawater, which is 62.0 % higher than that under dark condition. This study reveals that AOPEI-C-PAN fiber adsorbent holds great potential in practical uranium extraction applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hyperbranched phosphate groups were grafted onto electrospun nanofibers. • The proton transfer process could lead to the zwitterionic structures. • The fiber adsorbents exhibited excellent adsorption performance towards UO 2 2+. • The nanofibers also showed anti-bacterial adhesion and anti-protein adhesion. • The fiber adsorbents had good potential for the uranium extraction from seawater.. The development of efficient adsorbents with anti-biofouling properties for uranium extraction from seawater is highly attractive to meet the growing demands for energy. However, traditional fiber adsorbents still suffer from the challenge of weak binding energy, low functional group density, and inefficient antifouling ability. Herein, inspired by the structures of phospholipid, the bio-inspired zwitterionic phosphate groups were created onto the electrospun nanofibers to manipulate the affinity with uranium and the anti-biofouling property. Additionally, hyperbranched grafting reaction together with thin diameters of the fibers were applied to significantly improve the available density of functional groups. The constructed hyperbranched zwitterionic phosphate groups functionalized nanofiber adsorbents (ZP-PAN fibers) exhibited high distribution coefficient k d (7.38 × 106 mL/g) and large adsorption capacity (1294.0 mg g−1) in the uranium-spiked seawater, surpassing most of reported polymeric adsorbents. ZP-PAN fibers also showed good selectivity against competitive cations and stable reusability. Owing to their zwitterionic structures, ZP-PAN fibers had satisfactory anti-adhesive ability toward bacteria and protein. Consequently, the uranium could be effectively extracted by ZP-PAN fibers from natural seawater with the extraction capacity of 8.1 mg g−1 after contacting with seawater for 15 days. This work demonstrates a new functionalization selection for nanofiber materials and provides a promising adsorbent in the practical uranium extraction from seawater. [ABSTRACT FROM AUTHOR]