Biodiesel synthesis through Gossypium hirsutum oil transesterification using reusable nanocatalysts: An energy intensive approach optimization

Abstract

The present study intends to synthesize biodiesel from Gossypium hirsutum (cottonseed) oil using reusable copper (Cu) nanoparticles and optimize the transesterification process parameters to achieve a higher yield of Gossypium hirsutum biodiesel (GHB). The Cu nanoparticle was synthesized through the polyol method, and its fundamental characteristics were analyzed using scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The cottonseed oil, obtained through mechanical expeller, was then subjected to a two-step transesterification process for the conversion into GHB. Key process parameters such as Cu catalyst concentration (CuC), methanol-oil-ratio (MOR), and reaction time (RT) were optimized at a reaction temperature of 60 °C. The GHB’s elemental composition, Fourier-transform infrared spectroscopy, and physicochemical properties were analyzed. The results indicate that the nanoparticle characterization provided valuable insights into its properties, showcasing its recyclability for five consecutive cycles. The optimized process parameters for achieving a higher GHB yield were determined as CuC of 211 ppm, MOR of 8.5, and RT of 104.5 minutes, resulting in GHB yield of 95.6%. Furthermore, an exploration of an energy-intensive approach revealed that a slight reduction in CuC by 1% and an increase in the MOR by 2.4% significantly reduced the RT by 36.3%, with only a marginal decrease in GHB yield (2.6%). Confirmation experiments validated the predicted values, and the fuel properties of GHB strongly support its efficacy as a valuable fuel source.