Bioinspired electrostatic layer-by-layer assembly membranes constructed based on mild strategy for uranium extraction from seawater.

• PDA and PEI co-deposition combined with electrostatic self-assembly realizes mild surface modification. • The membrane with 3 functional layers exhibits the best adsorption performance (adsorption capacity = 142.25 mg·g−1). • This membrane can achieve over 90 % uranium removal within 90 min in dynamic filtration. • DFT calculation results indicate that the PEI/PA-U mode exhibits the most stable structure. Developing simple and efficient new strategies for uranium extraction from seawater (UES) is crucial for addressing the energy crisis. Here, we proposed a mild strategy to prepare a layer-by-layer assembly membrane (LAM) by polydopamine (PDA) and polyethyleneimine (PEI) co-deposition coupled with polyethyleneimine/phytic acid self-assembly for efficient uranium extraction. By regulating the number of self-assemblies, the performance of the membrane could be easily adjusted. The functional coating's rich active groups (–NH 2 , -PO 4 3-, –OH) provided a good adsorption performance for the modified membrane, with a static adsorption capacity of 142.25 mg·g−1. Meanwhile, it possessed excellent dynamic removal rate, which could achieve over 90 % uranium removal within 90 min. The LAM also exhibited exceptional adsorption selectivity, boasting a remarkable 9:1 ratio in extracting uranium and vanadium. Furthermore, the strong adhesion of PDA endowed the material with good stability, and the adsorption capacity only decreased by 23 % after 5 cycles. DFT calculations proved that PEI/PA-U was the most stable model. Particularly, the adsorption capacity of LAM in natural seawater can reach 0.99 mg·g−1. With the simple and mild preparation process, along with the excellent adsorption performance, the LAM membrane holds great promise for seawater uranium enrichment. [ABSTRACT FROM AUTHOR]