Na Jiang, Tingting Zhang, Wei Li, Jingyi Sun, Jinlin Hu, Minghua Lei, Mengyi Yuan, Weihua Li, Rui Lü, Dadong Shao
Developing adsorbents that couple high uranium affinity with durability in complex environments remains a pivotal challenge for efficient uranium harvesting. Here, we report a hierarchically engineered magnetic composite, Fe 3 O 4 @PAO@MPN-Met, that integrates (i) a superparamagnetic Fe 3 O 4 core for rapid separation, (ii) an amidoxime-rich polyamidoxime (PAO) shell for uranyl chelation, (iii) a bioinspired metal–polyphenol network (MPN) adhesive layer, and (iv) an in situ mineralized Cu 2+ / d -methionine ( d -Met) metal–organic framework (MOF) that imparts long-lasting antibiofouling activity. Stepwise solvothermal synthesis, surface grafting, and self-assembly preserve nanoscale morphology while reducing the saturation magnetization only to 16.4 emu/g─still sufficient for 1 min magnetic separation. Under optimal conditions, the material achieves a maximum uranium uptake of 272 mg/g, fitting the Langmuir model and quasi-second-order kinetics, indicative mainly of monolayer chemisorption controlled. Thermodynamic analysis reveals a spontaneous, endothermic, and entropy-driven process. The composite shows outstanding selectivity, with uranyl distribution coefficients at least 2 orders of magnitude higher than those of competing ions. After five adsorption–desorption cycles using 0.1 M HNO 3, 80% of the initial capacity is retained. Crucially, the Cu-Met nanochannels confer broad-spectrum antibacterial performance, suppressing Pseudomonas aeruginosa formation by 98.54%. In natural Bohai Sea water, after 7 days of adsorption, the uranium adsorption capacity is 0.322 mg/g, highlighting its salt tolerance and antifouling resilience. This multifunctional design, marrying strong amidoxime chelation, magnetic recoverability, and MOF-mediated antibacterial action, offers a viable route toward selective, reusable, and biofouling-resistant adsorbents for large-scale uranium harvesting from seawater.