Comparison of Two-Dimensional Graphene Oxide Synthesis Methods and Biological Activity Evaluation

Graphene Oxide (GO) 2D (two-dimensional) material, comprised of sp2 hybridized carbon atoms and has properties and applications in various fields such as medical, environmental, and other industries. The present study aims to synthesize GO using four different methods and characterize them by FT-IR, CHN, XRD, Raman, SEM, and EDS techniques. Finally, evaluated their antibacterial activities of them. For this purpose to synthesize GO, four methods of modified Marcano (KMnO4, H2SO4/H3PO4), Hummers methods (KMnO4, NaNO3, H2SO4), modified Hummers (KMnO4, H2SO4) and the Brodie method (KMnO4, H2SO4, HNO3) were compared. As well as, the antibacterial activities of all four methods were evaluated for gram-positive (S. aureus and M. luteus) and gram-negative (E. coli and V. harveyi) bacteria by disk diffusion method. The results of this research showed that Marcano’s method excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. Marcano’s method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or two methods with additional KMnO4. The average size of the synthesis of GO with Marcano’s method was estimated by the Debye-Scherrer equation as around 19.7 nm. The results of this research showed that synthesized GO with four different methods did not have any antibacterial activities.