Magnetic graphene oxide/MgAl-layered double hydroxide nanocomposite: One-pot solvothermal synthesis, adsorption performance and mechanisms for Pb2+, Cd2+, and Cu2+

The magnetic graphene oxide and MgAl-layered double hydroxide nanocomposite (MGL) was synthesized via a simple one-pot solvothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) and N-2 adsorption-desorption. The results proved that the MGL nanocomposite had typical features of graphene oxide and MgAl-layered double hydroxide. Moreover, the MGL had magnetism which related to the fabrication of Fe3O4 during the solvothermal reaction, and could be easily separated from mixture with easy magnetic separation assistance. Subsequently, the MGL was used to evaluate the adsorption efficiency for lead, copper and cadmium in aqueous solutions by batch equilibrium experiments. The MGL showed excellent adsorption ability for Pb2+, Cu2+, and Cd2+. The pseudo-second-order kinetic equation and Langmuir model well fit the adsorption kinetic data and isotherm data, respectively. Furthermore, the adsorption mechanisms of Pb2+, Cu(2+ )and Cd2+ by MGL were detailed conducted by XRD and XPS analysis, and could be ascribed to the surface complexation, precipitation and isomorphic replacement.