Development and characterization of magnetic metal organic frameworks as novel highly-efficient scavengers for uranium capture

The combination of metal - organic frameworks (MOFs) and magnetic nanoparticles has been demonstrated their prospective for sequestration of heavy metal or radionuclides. In this work, five kinds of magnetic metal - organic framework including ZIF-67@Fe3O4, ZIF-8@Fe3O4, CuBTC@Fe3O4, MIL101(Fe)@Fe3O4, and MOF74@Fe3O4, was prepared and used as novel highly-efficient scavengers for the capture of U(VI) from aqueous environment. These magnetic nanocomposites before and/or after U(VI) capture were characterized by FTIR, SEM-EDS, XRD, TEM, BET, and XPS analyses. A batch technique was applied for the capture of U(VI) using these magnetic nanocomposites at different operating parameters. The isotherm and kinetic data were more accurately fitted by the Langmuir and pseudo-second-order models, respectively. The ZIF-8@Fe3O4 and ZIF-67@Fe3O4 exhibit the potential to capture U(VI) from aqueous solutions with a maximum monolayer adsorption capacity of 441 and 1058 mg/g-1, respectively, by fitting the equilibrium data to the Langmuir model. The excellent adsorption capacity and the response to the magnetic field made these novel nanocomposites auspicious candidates in nuclear waste management.