Composites Containing Inorganic Ion Exchangers and Graphene Oxide: Hydrophilic–Hydrophobic and Sorption Properties (Review)

Abstract

This review is devoted to composite adsorbents, which contain inorganic ion exchangers and graphene oxide (GO). Morphology of the composite materials is considered. It has been shown that a small amount of GO loses the structure of the primary nanoparticles of inorganic supports due to the adsorption of nanosheets on their surface. When a small amount of inorganic ion exchanger is incorporated into GO, its particles disturb crystal structure of the carbon material. As opposed to reduced GO, the phenomenon of “superhydrophilicity” has been found for GO using a method of standard contact porosimetry. It means stronger swelling of this material in water compared with ideally wetting octane. Similar behavior has been found for the composite based on hydrated zirconium dioxide. The method gives high specific surface area of GO (2000−2400 m2 g−1); these values are close to theoretical magnitude (≈2600 m2g−1). High values of surface area are caused by disjoining pressure of octane or water, which penetrate between GO nanosheets as opposed to nitrogen. GO affects adsorption properties of inorganic ion exchangers: this carbon material enhances cation exchange and depresses the adsorption of anions. Hydrophobic regions of GO are responsible for the adsorption of organic compounds.