One-pot synthesis of graphene oxide and Ni-Al layered double hydroxides nanocomposites for the efficient removal of U(VI) from wastewater

Abstract

Graphene oxide and Ni-Al layered double hydroxides (GO@LDH) nanocomposites were synthesized via a one-pot hydrothermal process, and characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy in detail. The exploration of U(VI) sorption on GO@LDH surface was performed as a function of ionic strength, solution pH, contact time, U(VI) initial concentrations and temperature. Results of Langmuir isotherms showed that the sorption capacity of GO@LDH (160 mg/g) was much higher than those of LDH (69 mg/g) and GO (92 mg/g). The formed surface complexes between surface oxygen-containing functional groups of GO@LDH and U(VI) turned out to be the interaction mechanism of U(VI) with GO@LDH. According to the thermodynamic studies results, the sorption interaction was actually a spontaneous and endothermic chemical process. The sorption isotherms were better fitted with the Langmuir model compared with other models, which suggested the interaction was mainly dominated by monolayer coverage. The GO@LDH nanocomposites provide potential applications as adsorbents in the enrichment of radionuclides from wastewater in nuclear waste management and environmental remediation.