Characterization of reduced graphene oxide supported mesoporous Fe2O3/TiO2 nanoparticles and adsorption of As(III) and As(V) from potable water

Abstract

The removal of hazardous anions is essential to supply safe drinking water. In this study mesoporous Fe2O3/TiO2 was synthesized by sol–gel route using Pluronic P123 as the structure directing agent. The synthesized mesoporous Fe2O3/TiO2 nanoparticles dispersed over the reduced graphene oxide, to suppress the aggregation of the nanoparticles and to expose more number of active sites present in the nanoparticles. The mesoporous nature of the nanoparticles was confirmed from low angle X-ray diffraction. The reduced graphene oxide supported Fe2O3/TiO2 nanoparticles was characterized by FT-IR, Raman, XPS, N2 sorption, HR-TEM and SEM. The reduced graphene oxide supported Fe2O3/TiO2 nanoparticles was tested for the sorption of both arsenate (AsV) and arsenite (AsIII) in water. The equilibrium adsorption was attained within 15mins for both As(III) and As(V). The maximum adsorption capacity for As(V) and As(III) was found to be 99.5 and 77.7mg/g at pH 6 and 7 respectively. The sorption was found to be high in the pH range of 6–7. The low adsorption at lower and higher pHs other than 6 and 7 was due to zero point charge of nanocomposite which is equal to 6. The IR spectrum showed characteristic vibrations for arsenate in the nanocomposite. The recyclability study of nanocomposite not only confirmed the stability but also exhibited same sorption capacity for four cycles. This nanocomposite could be used for the removal of other hazardous inorganic ions.