College of Chemistry, Nanchang University, Nanchang 330031, China.
College of Chemistry, Nanchang University, Nanchang 330031, China.
J Hazard Mater. 2022 Mar 5;425:127951. doi: 10.1016/j.jhazmat.2021.127951. Epub 2021 Nov 29.
Uranium is a key element in the nuclear industry and also a global environmental contaminant with combined highly toxic and radioactive. Currently, the materials based on post-modification of amidoxime have been developed for uranium detection and adsorption. However, the affinity of amidoxime group for vanadium is stronger than that of uranium, which is the main challenge hindering the practical application of amidoxime-based adsorbents. Herein, we synthesized a fluorescent covalent organic framework (TFPPy-BDOH) through integrating biphenyl diamine and pyrene unit into the π-conjugated framework. TFPPy-BDOH has an excellent selectivity to uranium due to the synergistic effect of nitrogen atom in the imine bond and hydroxyl groups in conjugated framework. It can achieve ultra-fast fluorescence response time (2 s) and ultra-low detection limit (8.8 nM), which may be attributed to its intrinsic regular porous channel structures and excellent hydrophilicity. More excitingly, TFPPy-BDOH can chemically reduce soluble U (VI) to insoluble U (IV), and release the binding site to adsorb additional U (VI), achieving high adsorption capacity of 982.6 ± 49.1 mg g. Therefore, TFPPy-BDOH can overcome the challenges faced by current amidoxime-based adsorbents, making it as a potential adsorbent in practical applications.
铀是核工业的关键元素，也是一种具有放射性和毒性的全球性环境污染物。目前，基于偕胺肟后修饰的材料已被开发用于铀的检测和吸附。然而，偕胺肟基团与钒的亲和力强于铀，这是阻碍偕胺肟基吸附剂实际应用的主要挑战。在此，我们通过将联苯二胺和芘单元整合到π-共轭骨架中，合成了一种荧光共价有机骨架（TFPPy-BDOH）。由于亚胺键中的氮原子和共轭骨架中羟基的协同作用，TFPPy-BDOH 对铀具有优异的选择性。它可以实现超快的荧光响应时间（2s）和超低的检测限（8.8nM），这可能归因于其固有规则的多孔通道结构和优异的亲水性。更令人兴奋的是，TFPPy-BDOH 可以将可溶性 U（VI）化学还原为不溶性 U（IV），并释放结合位点以吸附额外的 U（VI），实现了 982.6±49.1mg/g 的高吸附容量。因此，TFPPy-BDOH 可以克服当前偕胺肟基吸附剂面临的挑战，使其成为实际应用中潜在的吸附剂。
