Preparation of nano-carbon powders drying at room temperature

The nano-carbon powders were prepared by sol-gel method, in which the coal tar pitch was first oxidized into aqua-mesophase pitch (AMP) by mixtures of concentrated sulfuric acid and nitric acid, and then the AMP was dissolved in aqueous solution of ammonia hydroxide to form the carbonaceous hydrogel, which was directly exchanged with ethanol to remove water and dried at room temperature. The AMP, the primary nano-carbon powders and their heat-treated products were characterized by FT-IR, TG, XRD and TEM method. The results show that the nano-carbon powders can successfully be prepared by drying at room temperature; the ball-like nano-carbon powders are well distributed with an average size of about 20 nm and have a turbostratic carbon structure. In the reaction of coal tar pitch with mixing acids, the reaction of nitration, oxidation and sulfonation was mainly involved. The pyrolysis process can be divided into four stages, including removal of ethanol and water, pre-pyrolysis, pyrolysis and rearrangement of carbon structure.