Synthesis and Characterization of Graphene Oxide from Residual Biomass

Graphene oxide (GO) is a member of the graphene family that is intensively used in many fields such as electronics, environmental protection, and biomedical applications. GO is mainly produced from commercially available graphite powder. In this study, however, GO was synthesized from alternative carbon-rich biomass residues that are readily available: spent tea leaves, and coffee waste. These residues were treated with dilute HCl to remove impurities and then soaked in NaOH to activate their carbon. Highly porous GO nanomaterials were successfully synthesized using the modified Hummer's method after pyrolysis of the biomasses at a moderate temperature. These nanomaterials were characterized using FTIR, Raman spectroscopy, SEM, and XRD. FTIR results indicated the removal of oxygen (C-O and O-H bonds), carboxyl, carbonyl, carboxylic, and epoxy functional groups from the biomass through pyrolysis. Raman spectroscopy of the GO particles revealed the extent of the oxidation process. SEM images showed vascular-shaped graphene layers with porous and semi-porous surfaces. X-ray diffraction patterns showed an amorphous shape. The properties of the synthesized GO particles were compared with GO produced from the conventional source: graphite. The results indicated considerable similarities. Hence, biomass residuals can be considered a viable, environmentally-friendly source for GO.