Hybridization of graphene sheets and carbon-coated Fe3O4 nanoparticles as a synergistic adsorbent of organic dyes

Abstract

Magnetic graphene–Fe3O4@carbon (GFC) hybrids with hierarchical nanostructures have been synthesized and their application as an adsorbent for the removal of organic dyes has been investigated. Graphene–Fe3O4 hybrids were first prepared via a facile one-pot solvothermal process, then carbonaceous coatings on Fe3O4 nanoparticles of nanometer thickness were synthesized by a hydrothermal carbonization process using eco-friendly glucose as a carbon source. Graphene sheets acting as two-dimensional (2D) substrates can effectively prevent the Fe3O4 nanoparticles from aggregating and enable a good dispersion of these magnetic nanoparticles. The carbonaceous layer protects the Fe3O4 nanoparticles in acidic environments and greatly enhances the specific surface area of the hybrids which is beneficial for the removal of organic dyes, such as methylene blue (MB). The resultant GFC hybrids exhibit great adsorption properties not only in water but also in acidic environments, and about 86% and 77% of the dye removal efficiency can be retained after five adsorption–desorption cycles in water and 1 M HCl, respectively. The rapid and efficient adsorption of organic dyes from water as well as acid suggests that the GFC hybrids have potential environmental applications as alternatives to commercial materials in wastewater treatment for the removal of organic dyes.