Enhanced Seawater High‐Purity Uranium Extraction Coupled With Microplastic Degradation by Quaternary Amine Tuned Microenvironment of COFs

ABSTRACT Photocatalytic uranium extraction coupled with microplastic degradation from seawater is a sustainable and promising approach for solving the energy crisis and ocean pollution. Covalent organic frameworks (COFs), one of the emerging porous crystal materials, provide a prospective molecular platform for uranium extraction and microplastics degradation benefiting from their strong adsorption capacity of porous structure and excellent photogenerated carrier properties, but still face enormous challenges of low uranium extraction capacity and product purity, caused by the impurity metal ions in seawater occupying adsorption sites. Herein, we report a new strategy of shielding impurity metal ions, by quaternary amine tuned microporous environment of COFs, which increases the distribution coefficient (K d ) and adsorption capacity (Q e ) of uranium (UO 2 (CO 3 ) 3 4− ) by about 18 000% and 782.0%, respectively, compared with pristine TAPT–TPA COFs. During the photocatalytic process, the adsorbed UO 2 (CO 3 ) 3 4− is photocatalytically reduced to UO 2 powder, the microplastics are oxidized into formic acid (FA) essential chemicals. Experimental shows that the as‐made TAPT‐TPA(N + ) COFs exhibit a record‐breaking uranium extraction capacity of 31.7 mg g −1 and 100% conversion of microplastics to FA. The product purity of UO 2 and FA can reach 90% and 99.9%, respectively. Overall, this work brings a brand‐new scenario for simultaneously developing nuclear fuel and resolving microplastic ocean pollution.