Utilizing weak interactions to effectively recover and separate precious metals in solution is of great importance but the practice remains a challenge. Herein, we report a novel strategy to achieve precise recognition and separation of gold by regulating the hydrogen-bond (H-bond) nanotrap within the pore of covalent organic frameworks (COFs). It is found that both COF-HNU25 and COF-HNU26 can efficiently capture AuIII with fast kinetics, high selectivity, and uptake capacity. In particular, the COF-HNU25 with the high density of H-bond nanotraps exhibits an excellent gold uptake capacity of 1725 mg g-1 , which is significantly higher than that (219 mg g-1 ) of its isostructural COF (COF-42) without H-bond nanostrap in the pores. Importantly, the uptake capacity is strongly correlated to the number of H-bonds between phenolic OH in the COF and [AuCl4 ]- in water, and multiple H-bond interactions are the key driving force for the excellent gold recovery and reusability of the adsorbent.
Keywords: Covalent Organic Frameworks; Gold Recovery; Hydrogen-Bond Nanotrap; Porous Materials; Separation.
© 2023 Wiley-VCH GmbH.