In-situ generated CoBOx@Polyimide aerogel: Autocatalytic, antimicrobial, salt-tolerant and high-resilient adsorbents for U(VI) extraction

The extraction of uranium from seawater poses significant challenges due to the low uranium concentration, high salinity, wave crash, and microbial presence, requiring comprehensive performance evaluation of the adsorbent for pre-applications. To address these challenges, the in-situ generated cobalt borate/polyimide aerogels (CoBO@PIA) with customizable shapes are proposed as effective adsorbents for U(VI) extraction. Experimental results demonstrated that CoBO@PIA-2 exhibits a high adsorption capacity ( q max of 812.2 mg/g) and cost-effectiveness (0.685 $/g). The antimicrobial characteristics mitigate bacterial interference, ensuring the reliability and effectiveness of U(VI) extraction. In the presence of S. aureus , Vibrio alginolyticus and E. coli at a concentration of 10 4 CFU/mL, CoBO@PIA demonstrated a remarkable 696 %-1387 % increase in adsorption capacity compared to PIA. Moreover, the durability of these adsorbents enhances their longevity and reusability. Noteworthy is the autocatalytic behavior of the Co(BO 3 ) 0.81 @PIA, resulting in a decreased Gibbs free energy of the CoBO@PIA-2. In this process, where Co(II) transfers electrons to U(VI), facilitating the reduction of U(VI) to U(V/IV). During desorption, Co(III) receives electrons, achieving an internal cycle of electrons, facilitating re-reduction to the initial valence ratio range (1.24:1–1.13:1). This mechanism enables efficient reuse of CoBO@PIA-2 materials. thereby streamlining the adsorption process and improving overall extraction efficiency. The synergistic combination of cobalt borate and polyimide aerogel yields unique properties, including autocatalytic behavior, salt tolerance, and antimicrobial activity, making it suitable for diverse applications, including small modular reactors.