Synthesis of ketoxime-functionalized Fe3O4@C core–shell magnetic microspheres for enhanced uranium(vi) removal

Abstract

Ketoxime-functionalized carbon coated iron oxide (Fe₃O₄@C–KO) was synthesized and characterized by transmission electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy, and magnetic measurements. The essential factors affecting uranium(VI) adsorption from an aqueous solution of Fe₃O₄@C–KO, such as initial pH, contact time and temperature, were investigated. The adsorption is highly dependent on solution pH. Analysis of the experimental data using sorption kinetic models, reveal that the process follows a pseudo-second-order kinetic model. In addition, adsorption isotherms and thermodynamics were investigated. The adsorption of uranium(VI) from an aqueous solution onto Fe₃O₄@C–KO was fitted to Langmuir and Freundlich adsorption isotherms. The adsorption of uranium(VI) is well-described by the Langmuir isotherm. Thermodynamic parameters further show that the sorption is an endothermic and spontaneous process. Fe₃O₄@C–KO is a powerful and promising sorbent for the efficient removal of uranium(VI) from aqueous solutions.