Ecotechnological Valorization of Verbesina encelioides: A dual strategy for sustainable biodiesel production and invasive weed mitigation

Abstract

The global shift towards renewable energy has intensified the need for sustainable technologies. The present study investigates the invasive weed Verbesina encelioides (Cav.) Benth. & Hook. Ex A. Gray as a potential feedstock for biodiesel production, while managing ecological issues. The seeds contain large amounts of oil (33 wt%) and a very low level of free fatty acids (0.16 wt%), which allows one-step transesterification using a synthesized cobalt oxide (Co3O4) nanocatalyst prepared from seed husk (a waste product) as a precursor. The nanocatalyst was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and X-ray diffraction (XRD). These techniques verified the porous morphology, cobalt-oxygen-rich composition, and highly crystalline structure, thereby confirming the presence of active catalytic sites. Response Surface Methodology (RSM) with a Box-Behnken Design (BBD) was used to optimize the reaction parameters. Such as oil methanol molar ratio of 1:3, catalyst loading of 0.4 % wt., reaction temperature of 60 °C, and reaction time of 120 min, confirming the conversion of triglycerides into fatty acid methyl esters (FAMEs) and yielding a maximum biodiesel production of 97 %. The resulting biodiesel was characterized by FTIR, 1H and 13C nuclear magnetic resonance (NMR), and gas chromatography-mass spectrometry (GC–MS), indicating complete transesterification, with oleic acid methyl ester as the dominant FAME. Compared to conventional diesel, the synthesized biodiesel exhibits high oxidative stability and standard combustion properties; the nanocatalyst also maintains recyclability and catalytic activity across multiple catalytic cycles. These results highlight the dual advantages of controlling an invasive species and generating high-quality biodiesel, which aids in designing bio-powered energy systems, efficient application technologies, and a circular bioeconomy.