Abstract
In this paper methods for obtaining graphene oxide from rice husk were developed, which using a downward approach based on a four-stage strategy: preliminary carbonization, desilication, activation with KOH, and exfoliation and its comparison with the method of graphite oxidation. The samples were analyzed by elemental analysis, SEM, Raman, TGA and FTIR. The elemental analysis show that the proposed approach allows to produce graphene materials with a carbon content around 70% and rich in inorganic matter (0–20 wt.%) (K, Fe, Si). To remove inorganic contents, purification and functionalization step were applied. The Raman spectra of the samples indicate the presence of a mixture of graphene layers and amorphous carbon. The thermogravimetric profile of samples is characterized by a slowly weight decrease up to a final residue of ~10 wt.%. FTIR spectra are characterized by the typical broad shape of large condensed aromatic carbon bonds; only the peak due to C=C stretching modes and the overlapped peaks between 900 and 1500 cm-1 due to skeleton vibrations are detected.