Selective extraction of uranium from water has attracted worldwide attention because the largest source of uranium is seawater with various interference ions (Na , K , Mg , Ca , 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.

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Artificially designed enzymes are in demand as ideal catalysts for industrial production but their dense structure conceals most of their functional fragments, thus detracting from performance. Here, molecularly imprinted porous aromatic frameworks (MIPAFs) which are exploited to incorporate full host-guest interactions of porous materials within the artificial enzymes are presented. By decorating a porous skeleton with molecularly imprinted complexes, it is demonstrated that MIPAFs are porous artificial enzymes possessing excellent kinetics for guest molecules. In addition, due to the abundance of accessible sites, MIPAFs can perform a wide range of sequential processes such as substrate hydrolysis and product transport. Through its two functional sites in tandem, the MIPAF subsequently manifests both hydrolysis and transport behaviors. Advantageously, the obtained catalytic rate is ≈58 times higher than that of all other conventional artificial enzymes and even surpasses by 14 times the rate for natural organophosphorus hydrolase (Flavobacterium sp. strain ATCC 27551).

Facile construction of ordered macroporous polyoxometalate-based metal–organic frameworks (POM@MOFs) to break the intrinsic microporous restriction is significant but remains challenging. On one hand, the POMs introduced improve the structural stability and modify the pores of MOFs, e.g., introducing functional catalytic and adsorptive units. Meanwhile, the acidic POMs severely affect the nucleation and growth of the POM@MOFs, resulting in complicated synthesis and difficult assembly control. Herein, a general approach has been developed to fabricate ordered macroporous POM@MOF single crystals, involving close-packed polystyrene (PS) nanosphere templates. The artificially selected polar solvents exerting strong solvent effect with POMs weaken the affinity between POMs and metal ions, thereby effectively stabilizing the precursors from assembly before filling into the PS template interstices. The weak alkaline carboxylate used regulates the in situ nucleation and growth of POM@MOFs through deprotonation of the ligands as well as coordinating modulation, affording a series of hierarchically cuboctahedral POM@MOF single crystals with ordered macropores (ca. 180 nm) and intrinsic micropores after template removal. The ordered macroporous structure and thinned microporous skeleton markedly improve mass diffusion properties, while the integral single-crystal lattice retains superior stability.

High-speed capturing of uranyl (UO 2 2+ ) ions from seawater elicits unprecedented interest for the sustainable development of the nuclear energy industry. However, the ultralow concentration (∼3.3 μg L −1 ) of uranium element leads to the slow ion diffusion inside the adsorbent particle, especially after the transfer paths are occupied by the coexisted interfering ions. Considering the geometric dimension of UO 2 2+ ion (a maximum length of 6.04−6.84 Å), the interlayer spacing of graphene sheets was covalently pillared with phenyl-based units into twice the ionic length (13 Å) to obtain uranyl-specific nanofluidic channels. Applying a negative potential (−1.3 V), such a charge-governed region facilitates a unipolar ionic transport, where cations are greatly accelerated and co-ions are repelled. Notably, the resulting adsorbent gives the highest adsorption velocity among all reported materials. The adsorption capacity measured after 56 days of exposure in natural seawater is evaluated to be ∼16 mg g −1 . This novel concept with rapid adsorption, high capacity, and facile operating process shows great promise to implement in real-world uranium extraction.