Facile and tunable synthesis of carbon–γ-Fe2O3 submicron spheres through an aerosol-assisted technology and their application in oil spill recovery

Abstract

Magnetic carbon submicron spheres possessing good sorption abilities and easy collection are of interest in environmental engineering including oil spill cleanup. Here we describe a facile one-step process for the preparation of spherical submicron carbon–γ-Fe₂O₃ composites with controllable magnetic susceptibility and strong adsorption capability. Based on an aerosol-assisted technology, common precursors including sucrose, iron sulfate and a tiny amount of concentrated sulfuric acid were distributed and confined to numerous aerosol droplets, where the concurrence of sucrose carbonization and phase transition in iron species rapidly led to the formation of spherical carbon–γ-Fe₂O₃ composites. Meanwhile, magnetic saturation (M_s) values and the surface properties of the obtained composites could be controlled by simply adjusting the heating temperature, and the highest M_s at 44.83 emu g⁻¹ is much greater than those of samples obtained using other common methods. In the application of oil spill cleanup including diesel, gasoline and crude oil, these magnetic carbon submicron spheres exhibit high adsorption ability, easy separation and good recyclability. Such a simple technology may serve as a generalizable process to synthesize other types of magnetic composites such as titanium dioxide, silica and aluminum dioxide for broad applications.