Radiation-induced one-pot synthesis of grafted covalent organic frameworks

Post-synthetic functionalization of covalent organic frameworks (COFs) is an alternative way to enhance and broaden their properties and potential applications. However, the chemical functionalization of COFs is a great challenge because traditional procedures are often time- and energy-consuming, while the crystallinity of COFs can be damaged under harsh conditions. Here we report the in-situ introduction of functional graft chains onto the skeleton of COFs during the synthesis process through the combination of radiation-induced synthesis and graft polymerization techniques under Co-60 gamma-ray radiation. The synthesis and functionalization of COFs are simultaneously accomplished in a chemical system under ambient conditions yielding a large number of different functionalized COFs. The obtained carboxyl-functionalized COFs exhibit excellent radioactive uranium removal capabilities from aqueous solution with fast uptake dynamics, high adsorption capacity, and excellent selectivity over other competing metal ions.