Constructing covalent organic frameworks via a multicomponent Doebner reaction for enhanced hydrogen peroxide-driven uranium removal

초록

Multicomponent reactions offer a powerful tool for incorporating diverse functionalities and new linkages into covalent organic frameworks (COFs). Thus, an irreversible three-component Doebner reaction is employed to synthesize four chemically robust dihydroquinoline carboxylic acid-(3-ketoenamine-linked functionalized COFs. Under light irradiation, COF-TpTapb-COOH, a functionalized COF synthesized via multicomponent Doebnerreaction, exhibits significantly superior uranium removal efficiency compared to its nonfunctionalized (3-ketoenamine-linked counterpart, COF-TpTapb. The photocatalytic mechanism for UO22+ immobilization on COF-TpTapb-COOH diverges from the conventional uranium reduction pathway. Instead, the process involves the formation of (UO2)O2(H2O)2 from the reaction between UO22+ and H2O2 generated in-situ under visible light. Notably, COF-TpTapb-COOH continues to generate H2O2even after uranium saturation, leading to a higher uranium removal capacity than COF-TpTapb and most previously reported COFs, underscoring its exceptional performance for uranium capture application. This work demonstrates that multicomponent Doebner chemistry can introduce new linkages and carboxylic acid sites into COFs, resulting in high performance frameworks.

키워드