Fabrication of rGO/Fe3O4 Magnetic Composite for the Adsorption of Anthraquinone-2-Sulfonate in Water Phase

Abstract

In the last few decades, anthraquinone and its derivatives (AQs) have been intensively applied to electrochemical, textile and dye, and photovoltaic industries. This has increased the levels of AQs in the natural environment and threatens human health. To remove AQs from the aqueous phase and recover these multi-functional molecules, a binary magnetic adsorbent, reduced graphene/Fe3O4 (rGO/Fe3O4), was synthesized via a hydrothermal method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman spectra, and thermogravimetric analysis (TGA) were then used to characterize the samples. The adsorption capacities of rGO/Fe3O4 to AQs were investigated by selecting anthraquinone-2-sulfonate (AQ2S) as a model molecule. The adsorption process followed the Langmuir adsorption isotherm and the second-order kinetics. The regeneration of adsorbents and the recycling of AQ2S and solvent were simultaneously achieved by Soxhlet extraction and rotary evaporation. These results confirm the high adsorption efficiency of rGO/Fe3O4 for removing AQs from water and provide a promising approach to recover the valuable molecules from the aqueous phase.