Harnessing non-edible Quercus incana seeds for sustainable and clean biodiesel production using seed-derived green Al2O3 nanocatalyst

The challenges of resource scarcity and waste deposition have increased raw material costs and imposed stricter waste management regulations. This study presents the first attempt to utilize high oil-yielding Quercus incana seeds (55.77 wt%, 0.28 % FFA) as a novel waste feedstock for synthesizing a bio-fabricated Al₂O₃ nanocatalyst and its application in producing high-quality biodiesel. A maximum biodiesel yield of 97.6 % was achieved under optimal conditions, including a 1:9 oil-to-methanol ratio, a 120-minute reaction time at 70 °C, and 0.25 % catalyst concentration. The formation of biodiesel was confirmed through various analytical techniques, such as ¹H- and ¹³C NMR, FTIR, and GC–MS. Additionally, the physicochemical properties of the biodiesel, including sulfur content (0.00047 wt%), TAC (0.20 mg KOH/g), cloud point, and pour point (−11 °C), were analyzed and compared to international biodiesel standards to ensure its stability, sustainability, and eco-friendliness. The production of biodiesel from Quercus incana, a non-edible, uncultivated waste feedstock, supports a greener revolution and a net-zero carbon society. It also promotes smarter waste management practices globally.