Synthesis and characterisation of carbon nanotubes from waste of Juglans regia (walnut) shells

Abstract

Walnut is one of the major dry fruits in the world. The annual production is around 3.8 million tons. There is a significant amount of walnut shell that is generated. Walnut shell is extremely tough and its degradation is very slow. Due to the significant problem it poses to the environment, utilisation of the shell in synthesis of various economically useful products has gained importance. Carbon nanotubes have been extensively utilised in the purification of industrial waste, as electrical conductors and adsorption of gases. The synthesis of carbon nanotubes from agro-industrial waste has gained importance due to the environmental safety associated with such an approach. Though a large number of studies exist on synthesis of activated carbon from Walnut shell, there are no reports on synthesis of carbon nanotubes from walnut shells. In our study, we report the synthesis of carbon nanotubes from walnut shells by pyrolysis. The synthesised nanotubes were characterised by X-ray diffraction, Fourier-transform Infrared spectroscopy and scanning electron microscopy. The study shows that synthesised nanotubes are multi-walled and are of high purity which could be applicable for any of the downstream applications.

Keywords:

• Walnut shell
• activated carbon
• carbon nanotube
• X-ray diffraction
• electron microscopy
• infrared spectroscopy