Synthesis of carbon nano-spheres and nano-tubes by thermal plasma processing of polypropylene

Syntheses of carbon nano-spheres and nano-tubes has been experimentally investigated via thermal plasma treatment of polypropylene as a common plastic waste material. Samples were treated in a furnace fitted with a twin DC thermal plasma torch. The resultant solid products were analyzed to determine their composition and morphology by EDS, SEM and TEM analysis. EDS and SEM analysis indicated that if the arc current is more than 100 A, solid products mainly consist of carbon black nano-structures with no impurities. SEM images also showed that the most portion of solid carbons are nano-spheres, however, TEM analysis provided evidences for existing some carbon nano-tubes between nano-spheres. It also demonstrated that with increasing the arc current, diameter of nano-tubes decreases. This method for synthesis of carbon nano-structures may find a way to be considered in industrial waste disposal installation and enhance the economic efficiency of thermal plasma waste treatment technology. Since these valuable nano-structures can be produced from thermal plasma treatment of some non-useful and environmentally hazardous waste materials.