Diethylenetriamine-functionalized reduced graphene oxide having more amino groups for methylene blue removal

Abstract

To obtain a high-performance amino-functionalized graphene, a new aminated graphene was prepared through a substitution reaction between chlorine-functionalized reduced graphene oxide and diethylenetriamine. The product exhibits high nitrogen content uniformly distributed in its sheets, with diethylenetriamine covalently attached to these sheets. The C–N bond in the product was certified by the Fourier transform infrared spectrum, which implies the successful attachment of diethylenetriamine to the graphene sheets. The average interlayer spacing is 0.42 nm. Diethylenetriamine features many more amino groups that act as ligands and spacers during adsorption and layer stacking processes. Compared with the adsorption capacities of reduced graphene oxide (77.1 mg g⁻¹) and activated carbon (46.7 mg g⁻¹), the product exhibits higher adsorption capacity (291.4 mg g⁻¹). The adsorption process fits the quasi-first-order model and Langmuir model. Physical adsorption plays a primary role in the adsorption process. The amino group of the product easily reacts with other chemicals, making it a useful intermediate for other graphene materials.