Ammoniating Covalent Organic Framework (COF) for High‐Performance and Selective Extraction of Toxic and Radioactive Uranium Ions

• Published in: Advanced science 2019-08, Vol.6 (16), p.1900547-n/a
• Main Authors: Xiong, Xiao Hong, Yu, Zhi Wu, Gong, Le Le, Tao, Yuan, Gao, Zhi, Wang, Li, Yin, Wen Hui, Yang, Li Xiao, Luo, Feng
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Communication; Communications; coordination interactions; covalent organic frameworks (COFs); Hydrogen bonds; ion exchange; Nuclear energy; Nuclear power plants; Porous materials; Seawater; synergic effect; Uranium; uranium adsorption
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.201900547

An ideal porous adsorbent toward uranium with not only large adsorption capacity and high selectivity but also broad applicability even under rigorous conditions is highly desirable but still extremely scarce. In this work, a porous adsorbent, namely [NH4]+[COF‐SO3−], prepared by ammoniating a SO3H‐decorated covalent organic framework (COF) enables remarkable performance for uranium extraction. Relative to the pristine SO3H‐decorated COF (COF‐SO3H) with uranium adsorption capacity of 360 mg g−1, the ammoniated counterpart of [NH4]+[COF‐SO3−] affords ultrahigh uranium uptake up to 851 mg g−1, creating a 2.4‐fold enhancement. Such a value is the highest among all reported porous adsorbents for uranium. Most importantly, a large distribution coefficient, KdU, up to 9.8 × 106 mL g−1 is observed, implying extremely strong affinity toward uranium. Consequently, [NH4]+[COF‐SO3−] affords highly selective adsorption of uranium over a broad range of metal ions such as SU/Cs = 821, SU/Na = 277, and SU/Sr = 124, making it as effective uranium adsorbent from seawater, resulting in amazing uranium adsorption capacity of 17.8 mg g−1. Moreover, its excellent chemostability also make it an effective uranium adsorbent even under rigorous conditions (pH = 1, 8, and 3 m acidity). A concept of ammoniating a covalent organic framework (COF) as high‐performance uranium adsorbent is explored. The resulting material affords outstanding uranium adsorption performance, suggesting it as an ideal uranium adsorbent. This work outlines a fundamental designing rule for COFs as high‐performance uranium adsorbent.