Sustainable Production of Biodiesel from Novel and Non-Edible <i>Ailanthus altissima</i> (Mill.) Seed Oil from Green and Recyclable Potassium Hydroxide Activated <i>Ailanthus</i> Cake and Cadmium Sulfide Catalyst

Heterogeneous catalyst prepared from Ailanthus altissima oil cake along with cadmium sulphide catalyst proved to be an efficient, cost-effective and sustainable source of biodiesel synthesis from Ailanthus altissima (Mill.) seed oil. Ailanthus altissima (Mill.) is a non-edible wild plant having significant oil content of 40%, being an ideal low cost and sustainable source of biodiesel production. After extraction of oil from the seeds, the remaining Ailanthus cake was treated through different techniques to be used as a novel heterogeneous catalyst. Free fatty acid content of the seeds was measured as 0.7%, which is very reasonable for effective trans-esterification process. The potassium hydroxide (KOH)-activated Ailanthus cake (KAC), calcined Ailanthus cake (CAC) and cadmium sulphide nanoparticles (CdS) were characterised with different techniques such as SEM at different magnifications, XRD and EDX. These catalysts were effectively utilised for biodiesel production owing to promising reusability, cost-effective and eco-friendly behaviour. For trans-esterification of Ailanthus altissima oil (AAO), the operating conditions on which maximum biodiesel yield obtained were 3:1 methanol to oil molar ratio, 0.5 wt.% catalyst concentration, 90 min reaction time, 60 °C and 600 rpm. The fuel properties of biodiesel obtained from Ailanthus altissima (Mill.) were also determined and analysed in detail. These properties, such as viscosity, density, pour point and cloud point, fall within the limits set by international standards of biodiesel