Synthesis and characterization of graphite oxide, graphene oxide, and reduced graphene oxide from graphite waste using modified hummers' method and zinc as reducing agent

In this paper, synthesis of graphite oxide, graphene oxide (GO), and reduced graphene oxide (rGO) from the spent pot lining (SPL) of aluminum industrial waste using modified Hummers' method and zinc as reducing agent is examined. The effects of ultrasonication time from 1 to 2 h and Zn mass ranging from 8 to 24 g as reducing agent were observed in detail for reduction reaction of GO into rGO. The chemical structures and morphology of the samples were confirmed through Fourier Transform Infrared Spectroscopy (FTIR), Particle Size Distribution (PSD), Scanning Electronic Microscopy-Energy Dispersive X (SEM-EDS), and X-ray Diffraction (XRD) characterizations. The FTIR analysis confirmed the formation of GO. Although some restacking/unexfoliated graphite structures showed a diffraction peak at 2θ of 26.54°, the XRD analysis clearly exhibited a peak at 2θ of 20.04°, assigned to rGO after reduction of the GO. The smallest particle size of rGO was observed in the range of 1 to 10 μm when under ultrasonication time of 1 h and Zn mass of 8 g. The FTIR spectrum of GO showed that there was a functional group C=C, which is an indication of rGO formation due to the covalent bonding of the graphene structure. SEM image of the rGO showed that the morphology seemed thick and layer stacking. The quality of rGO produced in this study needs to be improved further to meet requirements for applications.