Comparative study of microwave and conventional solvothermal synthesis for magnetic carbon nanocomposites and bio-oil from rice husk

This article provides a comparative study of advanced single pot microwave versus conventional solvothermal co-precipitation synthesis for producing magnetic carbon nanocomposites and bio-oil from rice husk. The aim was to produce nanocomposites composed of magnetic nanoparticles and novel graphene on the surface of hydrochar improving the reaction efficiency. The experiments were conducted at two different temperatures (140 °C and 180°C). The processing time was varied from 0.5 to 2h. The main focus of the study was to investigate the effect of process parameters on the yield, thermal stability and morphology. Microwave-assisted solvothermal carbonisation (MSTC) provided a higher yield of bio-oil compared to solvothermal carbonisation (STC) due to more effective heat transfer to the core of the material. Microwave processing also resulted in less C-C and C-H vibrations as measured by FTIR. Transmission electron microscopy confirmed the presence of well-dispersed nanoparticles, ranging in size from 5 to 20nm in both MSTC and STC. Thermal stability of the nanocomposite materials was significantly higher for conventional solvothermal synthesis compared to the microwave system.