Trace Nanocopper-Driven Surface Microstructural Engineering of Polyamidoxime Fibers for Enhanced Uranium Extraction from Seawater

Polymer fibers are leading adsorbents for large-scale uranium extraction from seawater, yet their performance is hindered by microbial adhesion and an “emergent phenomenon” in which excessive ligand induces hydrogen-bond-driven microphase aggregation of polymer chains, limiting ligand accessibility. Herein, we develop a trace nanometal-driven surface microstructure engineering strategy to address these challenges. As a proof of concept, trace Cu/Cu x O nanoparticles are incorporated into PAO-grafted polyethylene fibers (CuPAO@PE) through in situ coordination during radiation-induced graft polymerization. Incorporation of only 0.2 wt % Cu/Cu x O nanoparticles effectively modulates polymer aggregation, creating abundant mesopores (∼5.2 nm). Consequently, CuPAO@PE exhibits a 9-fold increase in uranyl ion diffusion depth and a 23.8% enhancement in adsorption capacity, achieving 819.6 mg g –1 in single uranium solution compared with copper-free fibers (PAO@PE). The optimized microstructure, coupled with the antibacterial activity of Cu/Cu x O, enables CuPAO@PE to maintain robust antibiofouling performance and achieve 5.1 mg g –1 uranium uptake after six months in natural seawater. These improvements in adsorption and antibiofouling performance are achieved with only a 0.4% increase in material cost relative to PAO@PE. This work provides a cost-effective, scalable solution to simultaneously enhance adsorption performance, offering broader design insights for the development of efficient adsorbents for challenging marine environments.