An Electron Beam Irradiation Postsynthetic Lanthanide-Based Metal–Organic Framework for Extraction of U(VI)

The development of highly efficient uranium adsorbents is pivotal for the sustainable advancement of nuclear energy. In this study, we present an innovative electron beam (EB) irradiation-assisted postsynthetic modification (PSM) strategy to engineer defects within a lanthanide-based metal-organic framework, MOF-76, significantly enhancing its U(VI) adsorption capacity. Compared to pristine MOF-76, the EB-modified MOF-76 demonstrates a remarkable increase in uranium removal efficiency, achieving the highest removal rate at a cumulative radiation dose of 120 kGy─twice that of the pristine material. A comprehensive suite of characterizations, including powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), CO₂ sorption, electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and fluorescence lifetime and quantum yield measurements, confirms that the EB irradiation induces a high concentration of defects in MOF-76-120 kGy, primarily manifested as ligand vacancies, while preserving the overall framework structure and stability. XPS analysis further reveals that the irradiation-induced defects introduce numerous binding sites containing -COOH and -OH groups, which exhibit a strong affinity for U(VI). Our findings not only propel the development of advanced uranium extraction technologies but also offer valuable insights into the interactions between radiation and matter in porous crystalline systems.