Conversion of novel non-edible Bischofia javanica seed oil into methyl ester via recyclable zirconia-based phyto-nanocatalyst: A circular bioeconomy approach for eco-sustenance

The current study assesses Bischofia javanica Blume's potential as novel non-edible seed oil for environmentally benign biodiesel production using phyto-nanocatalyst, i.e., green nanoparticles (NPs) of zirconium oxide (ZrO₂) synthesized with aqueous leaf extract of the same plant via the biological method. Using response surface methods, the maximum yield (95.8 wt.%) was obtained at a 1:6 oil-to-methanol molar ratio, 2.5 wt.% catalyst loading, 70 °C reaction temperature and 2 h of reaction time. In addition, advanced analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) were used to characterize green nanoparticles. Six peaks in the GC–MS spectrum were identified, showing the presence of six different methyl esters such as methyl palmitate, methyl linoleate, methyl oleate, methyl stearate, methyl linolenate and methyl 11-eicosenoate. In addition, ¹HNMR and ¹³CNMR confirmed the high conversion yield of the esters group with distinct peaks at 3.649 ppm and 174.19 ppm. Biodiesel prepared from Bischofia javanica has fuel qualities that meet international standards. Fuel properties were found analogous to international standards viz. ASTM and EN. These include flash point (80 °C), density at 15 °C (0.8623 kg/L), kinematic viscosity (5.32 mm²/s), cloud (−11 °C), pour point (−8 °C) and sulphur content of 0.00047 wt.%. The results indicate that the green nanocatalyst and synthesized biodiesel from the Bischofia javanica appear to be highly reliable and cost-effective candidates for producing sustainable and eco-friendly biodiesel to overcome energy crises and climatic deteriorations, which would assist in the shift from a linear to a circular economy.