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Construction of covalent organic framework with unique double-ring pore for size-matching adsorption of uranium
Nanoscale ( IF 5.8 ) Pub Date : 2020-11-23 , DOI: 10.1039/d0nr06854c
Jie Zhang 1, 2, 3, 4, 5 , Lihong Zhou 1, 2, 3, 4 , Zhimin Jia 5, 6, 7, 8, 9 , Xiaofeng Li 5, 6, 7, 8, 9 , Yue Qi 5, 6, 7, 8, 9 , Chuting Yang 4, 10, 11, 12 , Xinghua Guo 5, 6, 7, 8, 9 , Shanyong Chen 5, 6, 7, 8, 9 , Honghan Long 5, 6, 7, 8, 9 , Lijian Ma 5, 6, 7, 8, 9
Affiliation  

The separation and recovery of key nuclides such as uranium and plutonium from effluents related to nuclear industry is of great significance for alleviating the shortage of nuclear energy resources and protecting the environment and human health. However, the high temperature, strong acidity and radioactivity of the nuclear effluents pose a severe challenge to the separation materials used in such conditions. The diversity of structure, flexibility of design, and excellent physicochemical stability of covalent organic framework materials (COFs) provide the possibility for the directional design and preparation of adsorbents for use under harsh conditions. Herein, three COFs with similar structure, different pore sizes and connecting modules were synthesized. The ingenious structure predesign enables Dp-COF to have three carboxyl groups oriented toward the pore center and laid out in appropriate spatial positions, which builds hydrogen-bonding bridges between carboxycarbonyl and hydroxyl groups, and thus constructs for the first time a unique COF material with a double-ring pore. The inner pore size of the “double-ring” is slightly larger than the diameter of uranyl hydrate, which leads to a size-matching adsorption of uranium by Dp-COF, thus greatly reducing the effect of protonation. Even in the simulated spent fuel reprocessing liquid with pH = 1.0, the adsorption capacity of Dp-COF for uranium can reach 66.3 mg g−1, and the adsorption capacity reaches 317.3 mg g−1 at pH = 4.5, which is very rare among the reported COFs. More excitingly, the removal rate for uranium reaches up to an unprecedented 99.8% due to the size-matching effect, more than any analogous adsorbents. This study not only proposes new ideas for the design and regulation of the microscopic configuration of COF materials, but also provides an alternative approach for the preparation of efficient uranium adsorbents.

中文翻译:

具有独特双环孔的共价有机骨架的构建,可实现铀的尺寸匹配吸附

从核工业相关废水中分离和回收铀和p等主要核素对于减轻核能资源短缺,保护环境和人类健康具有重要意义。但是,核废液的高温,强酸性和放射性对在这种条件下使用的分离材料提出了严峻的挑战。共价有机骨架材料(COF)的结构多样性,设计灵活性以及出色的理化稳定性为定向设计和制备在恶劣条件下使用的吸附剂提供了可能性。在此,合成了具有相似结构,不同孔径和连接模块的三种COF。巧妙的结构预设计使Dp-COF具有三个朝向孔中心并排列在适当空间位置的羧基,从而在羧基羰基和羟基之间建立了氢键桥,从而首次构建了具有以下特征的独特COF材料:双环孔。“双环”的内孔尺寸略大于铀酰水合物的直径,这导致Dp-COF对铀的尺寸匹配吸附,从而大大降低了质子化作用。即使在pH = 1.0的模拟乏燃料后处理液中,Dp-COF对铀的吸附容量也可以达到66.3 mg g 因此,首次构造了具有双环孔的独特COF材料。“双环”的内孔尺寸略大于铀酰水合物的直径,这导致Dp-COF对铀的尺寸匹配吸附,从而大大降低了质子化作用。即使在pH = 1.0的模拟乏燃料后处理液中,Dp-COF对铀的吸附容量也可以达到66.3 mg g 因此,首次构造了具有双环孔的独特COF材料。“双环”的内孔尺寸略大于铀酰水合物的直径,这导致Dp-COF对铀的尺寸匹配吸附,从而大大降低了质子化作用。即使在pH = 1.0的模拟乏燃料后处理液中,Dp-COF对铀的吸附容量也可以达到66.3 mg g-1,在pH = 4.5时吸附容量达到317.3 mg g -1,在所报道的COF中非常罕见。更令人兴奋的是,由于尺寸匹配效应,铀的去除率达到了前所未有的99.8%,比任何类似的吸附剂都高。这项研究不仅为COF材料的微观结构设计和调节提出了新的思路,而且为制备有效的铀吸附剂提供了另一种方法。
更新日期:2020-12-09
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