Potential industrial waste materials for graphene extraction

Interest on graphene and related materials is currently arising due to their excellent properties for several applications. To cope with the increasing need of their supply, different synthesis procedures have been proposed. The selection of the most suitable production approach mainly depends on the material characteristics required for the specific application. Moreover, the desired quantity and the final cost of the materials are also key points to be considered. Bottom-up and top-down methodologies have been extensively explored and developed, giving rise to graphene materials with diverse quality and characteristics. In bottom-up procedures, the self-assembly of carbon atoms to form graphene sheets is entailed, while in top-down routes graphite is used as the precursor to produce graphene materials. Top-down technologies can be easily scaled up at a reasonable cost; therefore they are considered more promising from an industrial point of view. Graphite with a high degree of crystallinity is the starting material in this synthesis process. However, natural graphite is a limited resource only found in countries like China, Brazil, and India. Fortunately, synthetic graphite can be synthesized using by-products from the carbochemical and petrochemical industries. Therefore, residues obtained as low-added value fractions can be transformed, following different technologies, into high-tech graphene-related materials suitable for their application in diverse scientific and industrial fields, such as energy storage, water treatment, and sensors, among many others.