Effective removal of arsenic from an aqueous solution by ferrihydrite/goethite graphene oxide composites using the modified Hummers method

This work presents the synthesis of graphene oxide and modified graphene oxide by adding oxygenated groups, using the modified Hummers method. The synthetized materials are characterized by Fourier-transform infrared spectroscopy, X-ray, isotherm adsorption curves, and kinetic adsorption tests. In addition, two varieties of ferric hydroxides, i.e., goethite and ferrihydrite, are coupled to the graphene oxide and the modified graphene oxide, and their arsenic adsorption properties are studied. Results show that the modified composites have a deviation from the linear van't Hoff equation, suggesting that multiple interactions and a multi-layer adsorption are occurring. Also, the results show that composites of graphene oxide/or modified graphene oxide with goethite have a better adsorption capacity than those coupled to ferrihydrite.