Bioenergy production from waste seed oil biomass of Cupressus sempervirens: A strategy for reducing environmental pollution

Biodiesel, derived from non-edible and spent oils, presents a cleaner and more sustainable alternative fuel source for diesel-powered engines. This study investigates the potential of converting non-edible Cupressus sempervirens seed oil into eco-friendly biodiesel using tellurium oxide nanoparticles synthesized with aqueous leaf extract of Calendula arvensis. Advanced techniques were utilized to characterize the catalyst, revealing its crystalline structure, with particles averaging 45 nm. Remarkably, the catalyst demonstrated efficient reusability over four cycles, achieving a peak yield of 93% under specific reaction conditions: a methanol to oil molar ratio of 8:1, a catalyst loading of 0.62 wt%, a reaction time of 120 min, and a temperature of 92.5 °C. Results from nuclear magnetic resonance spectrometry (¹H and ¹³C NMR) confirmed the successful conversion of the non-edible seed oil into methyl ester. Gas chromatography mass spectrometry (GC-MS) analysis identified 9-octadecenoic acid methyl ester as the predominant fatty acid methyl ester. The fuel properties of the synthesized biodiesel met international standards, with a high flash point (98°C), and ultra-low sulfur content of 0.0002%, highlighting its clean and cost-effective nature. This study contributes significantly to advancing bioproducts for a sustainable bioeconomy, presenting an integrated approach to bioenergy production that simultaneously addresses environmental and socio-economic concerns.