Síntese do grafeno a partir do grafite de pilhas exauridas

Abstract

The amount of waste generated and disposed of incorrectly is causing great damage to the environment. As a way of minimizing these impacts, the reuse of hazardous materials such as unused batteries present itself as an ecologically correct and intelligent way to obtain raw materials. In this sense, the objective of this work was the use of graphite rods of the exhausted cells aiming at the sustainability and reduction of costs for the production of graphene. The initial procedure was to separate the material of interest from the pile, followed by the reduction of the particle size, acid washing of the material and raising the pH to 7.0, ending the treatment of the residue. For graphene synthesis, the Hummers method was used with modifications to improve the efficiency of the reaction. First, it made the process of pre-oxidation of graphite by chemical agents, followed by the oxidation step. The reaction content was washed until the pH of the wash water was approximately 7.0, made the separation of the solid material and drying. A second method was evaluated called the adapted method, in which it occurs in only one step, adding reagents and at the end, the reaction is stopped with hydrochloric acid and the process of raising the pH near to 7.0 is started, with subsequent drying. The analyzes performed for the characterization of the samples by the DRX, FTIR, MEV and TXRF techniques indicated the formation of graphene oxide by the modified Hummers method with and without acid washing. However, for the adapted method it was not possible to clearly identify the formation of graphene oxide. It was observed that the acid washing process cooperated to improve the reaction product as it possibly removed impurities from the feedstock. In general, it was verified the feasibility of reusing the graphite stick contained in zinc-carbon cells for synthesis of graphene, and it is necessary to improve the process to ensure the technical, economic and environmental sustainability of the same.