共价有机框架稳定性提高及其在放射性核素分离中的应用

The Stability Enhancement of Covalent Organic Frameworks and Their Applications in Radionuclide Separation

共价有机框架(Covalent Organic Frameworks,COFs)是一类通过可逆反应制备的具有长程有序结构的晶态有机多孔聚合物,因其良好的耐辐照性、结构可设计性及可功能化特点有望在放射性核素高效吸附及作用机理探讨中发挥作用。但连接键可逆性降低了COFs的化学稳定性,本文系统地综述了COFs化学稳定性提高(包括连接键可逆性的降低、合成后可逆连接键向不可逆转化及连接键周围疏水环境构建)、晶型调控(包括合成条件、二维COFs层内共平面及层间堆叠作用力的影响及无定形聚合物结晶化)、功能化方法和其在放射性核素分离富集方面中的应用。通过增强COFs骨架的强度,引入特殊的功能化官能团或改变单体大小通过尺寸匹配效应来增强放射性核素离子与COFs的相互作用,并就COFs在该领域应用前景和研究方向进行了展望。

Covalent organic frameworks(COFs)are a class of crystalline organic porous polymers with long-range ordered structures prepared by reversible reactions.Due to high radiation resistance,structural designability and functionalization,COFs are expected to play a role in the efficient adsorption of radionuclides and the exploration of interaction mechanism.However,the reversibility of typical linkage bonds causes the limited chemical stability of COFs.This paper reviews the improvement strategies towards chemical stability of COFs(including the decrease of reversibility of linkage bonds,the post synthetic transformation from reversible bonds to irreversible ones,and the construction of hydrophobic environment around linkage bonds),crystalline control(including the influence of synthesis conditions,in layer coplanar and interlayer interaction for two-dimensional COFs and the crystallization of amorphous polymers),functionalization methods and the applications of COFs in the separation and enrichment of radionuclides.The interaction between radionuclides and COFs could be optimized by enhancing the strength of COFs skeleton,introducing special functional groups or changing the size of monomers.The application prospect and research focus of COFs in radionuclide separation are prospected.