The Impact of Hydrofluoric Acid in Enhancing the Purity of Coconut Shell-Derived Graphite Powder

The present study focuses on preparing graphite powder from coconut shell (CS), investigating the impact of hydrofluoric acid (HF) in eliminating silica and other contaminants. The synthesis of graphite powder involves a pyrolysis approach, where CS is heated to 900 °C and then treated with HF at varying sample-to-acid ratios. Several characterization techniques, such as Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and Raman spectroscopy, are utilized to validate successful graphite synthesis. XRD analysis reveals a distinct graphitic structure, with G4 showcasing a high graphitization degree of 95.35%, signifying superior crystal structure and high-quality graphite. FTIR analysis of coconut shell charcoal powder (CSCP) highlights different oxygen-related functional groups, effectively eliminated through HF washing, resulting in graphite with minimal impurities. Raman spectra of G4 exhibit fewer defects and lesser structural disorder compared to other samples. SEM image of CSCP demonstrates particles with irregular shapes, whereas G4 showcases a tightly packed graphitic structure. The results obtained show that HF has a significant impact on enhancing the quality of graphite prepared using CS. The study concludes that maintaining a CSCP-to-HF ratio of 1:4 (G4) yields graphite powder with desirable properties, including negligible impurities, excellent crystal structure, and fewer defects, comparable to pure graphite. Future work of this study aims to utilize CS-derived graphite powder for synthesizing graphene oxide (GO) and reduced graphene oxide (rGO).