Efficient elimination of U(VI), Th(IV) and Eu(III) from nuclear waste using MXenes-derived three-dimensional metal organic frameworks: Performance evaluation and mechanism insight

With the rapid development of nuclear power industry, the treatment of radioactive contamination had attracted more and more attention. Herein, the two-dimensional Ti3C2Tx MXenes were used as precursors to fabricate three-dimensional catechol-based MOFs (TiCu-HHTP) under the assistance of Cu(II) ions. The synthesis mechanism suggested that electrons were transferred from Ti3C2Tx to the electrostatically adsorbed Cu(II) ion for redox reaction, followed by Ti-C bond break to release Ti(IV) ion, and continuous chelation coordination of Ti (IV)/Cu(II) with HHTP. Batch experiment demonstrated that the maximum extraction capacity for U(VI), Th(IV) and Eu(III) on TiCu-HHTP were estimated to be 343.4, 85.7 and 96.7 mg/g, respectively, which were related to the single-layer chemisorption process. Meanwhile, kinetic studies have found that there was a synergy between diffusion control and mass transfer control. More importantly, TiCu-HHTP basically maintained its adsorption ability against radionuclides after three regeneration cycles. Mechanism analysis manifested that the excellent collection capacity was ascribed to the coordination and Lewis acid-base interaction between radionuclides and TiCu-HHTP. Thus, this TiCu-HHTP was not only a promising remediation agent, but also could provide some guidance in nuclear waste management.