Biofouling-resistant tannin/amidoxime functionalized fibers for long-term uranium extraction from seawater

Marine microorganisms pose a significant challenge to the long-term performance of uranium extraction materials in seawater applications, necessitating adsorbents resistant to biofouling. We introduce BWT-AO-CFs, an innovative adsorbent composed of collagen fibers(CFs) grafted with amidoxime groups(AO) and black wattle tannin(BWT), both known for their excellent uranium adsorption capabilities. The inherent antibacterial and anti-biofilm properties of BWT confer remarkable biofouling resistance to BWT-AO-CFs in seawater environments. Rigorous assessment of BWT-AO-CFs' adsorption performance in a simulated seawater system demonstrated its exceptional adsorption capacity, achieving a high uptake of 0.851 mmol g −1 for UO 2 2+ at an initial concentration of 0.269 mmol L −1 , under conditions of 323 K and pH 8.0. Notably, BWT-AO-CFs exhibited strong selectivity for UO 2 2+ even in the presence of coexisting ions in seawater, such as VO 2 − , Na + , K + , Ca 2+ , Mg 2+ , Mn 2+ , Ni 2+ , and Cl − . In simulated seawater tests, BWT-AO-CFs demonstrated a superior uranium extraction capacity of 9.13 mg g −1 within 7 days. Furthermore, extensive investigations into the biofouling resistance showed that after 90 days in seawater, BWT-AO-CFs maintained their initial morphology and structure, with only slight adsorption capacity reduction. This exceptional robustness to biofouling underscores the significant potential of BWT-AO-CFs for long-term and reliable uranium extraction from seawater.