Synthesis of Nickel Cobaltite/Multiwalled Carbon Nanotubes Composites and Their Application for Removing Uranium (VI)

Abstract

A facile hydrothermal method has been developed to prepare a nickel cobaltite/multiwalled carbon nanotubes (NiCo2O4/MWCNTs) composite. The structure and morphology of NiCo2O4/MWCNTs were tested by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscope, and nitrogen sorption isotherm. The nitrogen sorption isotherms of the NiCo2O4/MWCNTs composite indicate that NiCo2O4/MWCNT is a typical mesoporous material. The average pore width of NiCo2O4/MWCNTs is 10.0 nm. When serving as the adsorbent for uranium, the NiCo2O4/MWCNTs composite exhibits a high adsorption capacity, suggesting their potential use in water treatment. The influences of pH, temperature, and time on the adsorption efficiency of uranium by NiCo2O4/MWCNTs were studied. The experimental results show that the maximum adsorption capacity of NiCo2O4/MWCNTs for uranium(VI) is 247.4 mg g−1, suggesting that it is an effective uranium(VI) sorbent in water treatment. Thermodynamic analysis results show that the process is endothermic in nature. As the adsorption capacity does not increase significantly with the increase in T, the uranium adsorption by NiCo2O4/MWCNTs can be carried out at room temperature to reduce energy consumption. The NiCo2O4/MWCNTs composite can be a good alternative to remove uranium(VI).