Radiation Controllable Synthesis of Robust Covalent Organic Framework Conjugates for Efficient Dynamic Column Extraction of 99TcO4−

Abstract

Summary Anion-scavenging materials tailored for 99TcO4− trapping are urgently needed for both nuclear-related environmental remediation and management of spent nuclear fuel. For the first time, we report here an ultra-robust imidazolium-decorated covalent organic framework (COF) conjugate fabricated by an ionizing radiation strategy, for efficient capture of 99TcO4−. The charged imidazolium moieties are controllably anchored into the channel of the COF by simply adjusting the γ-ray dose, thereby leading to tunable ReO4− uptake up to 952 mg g−1 with high selectivity and fast kinetics. More importantly, the high porosity and ultra-robust nanofiber structure of the COFs make them ideal packing materials for dynamic column experiments. >99.98% ReO4−/TcO4− can be efficiently separated and re-collected, even after four adsorption-desorption cycles, ranking a new record of the elimination rate for ReO4− adsorption. The performance of these materials suggests attractive opportunities in practical applications for TcO4− removal from the environment and nuclear waste.