Molecularly Imprinted Porous Aromatic Frameworks and Their Composite Components for Selective Extraction of Uranium Ions

Abstract

Selective extraction of uranium from water has attracted worldwide attention because the largest source of uranium is seawater with various interference ions (Na⁺, K⁺, Mg²⁺, Ca²⁺, etc.). However, traditional adsorbents encapsulate most of their functional sites in their dense structure, leading to problems with low selectivity and adsorption capacities. In this work, the tailor-made binding sites are first decorated into porous skeletons, and a series of molecularly imprinted porous aromatic frameworks are prepared for uranium extraction. Because the porous architecture provides numerous accessible sites, the resultant material has a fourfold increased ion capacity compared with traditional molecularly imprinted polymers and presents the highest selectivity among all reported uranium adsorbents. Moreover, the porous framework can be dispersed into commercial polymers to form composite components for the practical extraction of uranium ions from simulated seawater.

Traditional adsorbents for the selective extraction of uranium have the disadvantages of low available surface areas, capacities, and selectivity. Thus, porous aromatic frameworks are decorated with tailor-made binding sites to obtain molecularly imprinted porous aromatic frameworks, which possess excellent capacities and selectivity due to more accessible porous spaces and the hierarchical porosity.

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