Characterization of phytosynthesized niobium oxide nanoparticle for efficient conversion of Grewia asiatica L. waste seed oil into sustainable fuel

The production of bioenergy and bioproducts from streams of biowaste has ignited interest in fostering a circular economy worldwide. This study investigates the potential of transforming Grewia asiatica L. waste seed oil into sustainable biodiesel using green-synthesized niobium oxide nanoparticle. Niobium oxide nanocatalyst was synthesized using aqueous leaf extract of Fumaria indica L. Advanced characterization techniques were employed to confirm the pure and nano-scale nature of the synthesized niobium oxide nanocatalyst. The synthesized nanocatalyst exhibited an average particle size of 31 nm, resulting in efficient catalytic activity that persited through the fifth cycle of transesterification. An optimum biodiesel yield of 90% was achieved under reaction conditions of a methanol to oil molar ratio of 9:1, a reaction time of 180 min, a temperature of 60 °C and a catalyst load of 0.32 (wt. %). Results of Gas chromatography mass spectrometry (GC–MS) analysis of G. asiatica-derived biodiesel revealed 5, 8-Octadecadienoic acid methyl ester as the primary fatty acid methyl ester, with the highest concentration. The fuel properties of G. asiatica-derived biodiesel complied with international standards. The minimal sulphur content of 0.0001% highlights the clean, environmentally benign and cost-effective nature of biodiesel synthesized from G. asiatica waste seed oil. This study contributes to the renewable alternative effort toward transitioning from a linear economy to a circular bioeconomy.