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

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 mono layer coverage.The GO@LDH nanocomposites provide potential applications as adsorbents in the enrichment of radionuclides from wastewater in nuclear waste management and environmental remediation.