Graphene oxide-mesoporous SiO2 hybrid composite for fast and efficient removal of organic cationic contaminants

Abstract In this study, we have developed a novel mesoporous SiO2 - graphene oxide hybrid material (SiO2NH2-GO) as highly efficient adsorbent for removal of cationic organic dyes from water. The fabrication of such a three-dimensional (3D) SiO2NH2-GO composite has been achieved via the condensation reaction between the amine units exposed on 3-aminopropyl-functionalized silica nanoparticles and the epoxy groups on surface of GO. As a proof-of-concept, SiO2NH2-GO was used for the removal of archetypical dyes from water and revealed outstanding maximum adsorption capacity towards methylene blue (MB), rhodamine B (RhB) and methyl violet (MV) at pH 10 reaching 300, 358 and 178 mg g−1 for MB, RhB and MV, respectively, thus outperforming the neat components of composite, i.e. GO and SiO2. Moreover, the adsorption process revealed that ∼99.7% of MB, RhB and MV have been removed in only 3 min thereby highlighting the superior nature of SiO2NH2-GO composite with respect to most of graphene oxide-based adsorbents of organic dyes. Finally, the composite was used in solid phase extraction (SPE) as column packing material, for continuous water purification, thus highlighting the great potential of SiO2NH2-GO for the large-scale removal of cationic dyes from aqueous solutions.