Pyrolysis Characteristics and Kinetics of Microalgal Residues

Abstract

In recent years, advanced nanotechnological developments and the widespread use of nanoparticles in industry have led to an increase in studies to increase nanoparticle production. In this context, the use of biochar as precursors to produce carbon nanotubes, which is the one of the most important nanostructured materials because of its unique properties, is one of these developments. Biochar is a coal-like material formed by the degradation of cellulose, hemicellulose, and lignin structures in the structure of biomass at high temperature in an anaerobic or a little amount of air environment and can be used as a precursor in the production of carbon nanotubes due to its high carbon content. The aim of this study is to evaluate the oil-extracted Chlorella variabilis microalgae residue in biochar production by pyrolysis and to use the produced biochar's as a precursor in carbon nanotube synthesis by microwave irradiation method. In this way, sustainability will also be ensured. In addition, the behavior of this residue during pyrolysis, pyrolysis kinetics and thermodynamic parameters are also determined by the thermogravimetric method. In this context, biochar production was carried out at 500 degrees C temperature, 20 degrees C/ min heating rate and 300 mL/min nitrogen gas flow. Pyrolysis kinetics and thermodynamic parameters were also calculated by using the Kissinger-Akahira-Sunosa and Flynn-Wall-Ozawa methods. According to the results which are obtained from experiments, it was understood that biochar produced from microalgae residues can be easily used in the production of carbon nanotubes. In future studies, it is thought that more efficient nanotube production can be realized by optimizing the production conditions or parameters of carbon nanotubes from microalgal biochar's and these produced nanotubes can be used in varied areas.