Synergistic enhancement of antibiofouling and uranium extraction from seawater with β-cyclodextrin microcapsules/polyamidoxime porous network membrane

Uranium extraction from seawater (UES) is considered a feasible strategy to ensure long-term development of nuclear energy. Herein, a novel anti-biofouling membrane adsorbent (CDM/PAO) with sustained-release effect was prepared by blending β-cyclodextrin microcapsules (β-CDM) as a hydrophilic additive with polyamidoxime (PAO) using phase inversion method. The addition of β-CDM enhanced the hydrophilicity of the membrane and facilitated the formation of a porous structure, which contributed to the increase in water flux and rapid mass transfer of UO₂²⁺ to the active sites. The synergistic effect between β-CD hydroxyl groups and amidoxime groups provided CDM/PAO with exceptional adsorption performance, with a maximum adsorption capacity of up to 653.31 mg·g⁻¹. Simultaneously, the sustained release of cinnamaldehyde from β-CDM imparted excellent antimicrobial properties to CDM/PAO, the uranium adsorption capacity only decreased by a maximum of 7.4 % in bacterial-containing uranium solutions. Remarkably, the CDM/PAO membrane was capable of treating a substantial volume of flowing seawater, achieving a uranium extraction rate of 84.73 % following a 15-day continuous filtration of 500 L of concentrated seawater. The outstanding performance of CDM/PAO is expected to expand the industrialization path of UES.