Síntesis de óxido de grafeno a partir del coque residual del petróleo

Abstract

Petroleum coke or petcoke is a by-product of oil refining used primarily by the iron and steel industry in iron smelting. During its combustion process, greenhouse gases such as CO2, SOx and NOx are generated. Additionally, since it is a particulate material, its accumulation in large open-pit areas has generated socio-environmental problems; therefore, it is necessary to search for new storage and reuse strategies. In this sense, considering that petcoke is composed of lamellar carbon and graphite, it makes it an optimal precursor for the synthesis of carbon-based materials such as graphene oxide (OG), which in turn is a starting material for obtaining graphene or reduced graphene oxide, using in various technological areas due to its novel properties. Some authors have carried out this synthesis by subjecting petcoke to various treatments between 1000 °C, 1200 °C up to 3000 °C, generating separation of amorphous carbon compounds until obtaining a graphitic structure, leading to greater energy and economic expense, and perhaps emission of gases such as COx, NOx and SOx. Therefore, in the present work, OG was synthesized from a petcoke sample with and without heat treatment at 1200 ° C, with prior spraying and removal of residues of polyaromatic compounds not anchored to the ordered structure, using toluene and dichloromethane, using the modified Hummer method. To determine the similarity between the synthesized materials and the OG obtained from the graphite, the products were characterized by UV-Vis showing absorbance bands at 240 nm, corresponding to the C = C conjugation transitions of π-π * present in the OG. The results obtained by FTIR-ATR spectroscopy showed similar bands corresponding to epoxy, ether, hydroxyl, carbonyl groups, aromatic groups, and carboxyls. Through X-ray diffraction (DRX) better results were obtained for petcoke without heat treatment, obtaining various levels of laminar carbon oxidation, represented by narrow peaks between 8 and 12 ° 2theta. The results obtained indicated the effectiveness of the Modified Hummer Method in the synthesis of OG from petcoke without heat treatment, obtaining better and similar results with respect to OG from heat-treated coke and from graphite.