Synthesis and characterization of magnetite and activated carbon binary composites

Magnetite and its composite materials with activated carbon were prepared using a co-precipitation method with Fe2+/Fe3+ at 60 °C under anaerobic conditions. Iron oxyhydroxide (goethite, α-FeOOH) was synthesized at a 5/1 OH−/Fe3+ molar ratio. Characterization of these composite materials and goethite was established using powder X-ray diffraction (PXRD), Raman spectroscopy, diffuse reflectance infra-red Fourier transform spectroscopy (DRIFTS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption–desorption analysis. Inhomogeneous growth of magnetite in the activated carbon was revealed by electron microscope images, N2 adsorption–desorption isotherm analysis, and the total Fe content in the composites were determined. Composite materials of activated carbon and iron oxide possess modified pore structure and oleophilicity relative to activated carbon and the iron oxide starting materials. The tunable adsorption properties of such materials were reported by Kwon et al. [53] for an organo-arsenical in aqueous solution and an independent kinetic study of selenite anion species. The unique behaviour of the composite materials were related to their relative composition and hydrophile–lipophile characteristics.