Single-stage waste oil conversion into biodiesel via sonication over bio-based bifunctional catalyst: Optimization, preliminary techno-economic and environmental analysis

To intensify biodiesel production, sonication and heterogeneous catalysis has received widespread focus from the research community. In this study, sonication was used for the single-stage biodiesel generation from waste oil catalyzed by KOH/corncob activated carbon. The results from response surface-based optimization showed 3 wt % catalyst loading, 5 min reaction time, and 18:1 methanol-to-oil molar ratio to be the optimal reaction con-ditions. The biodiesel yield was 88 % without the generation of soap, and it conforms to the standard ASTM criteria. The ultrasound-assisted heterogeneously catalyzed procedure was found to be favorable since it decreased the reaction time and eliminates saponification. Consequently, this combination enhances the overall biodiesel productivity, its economic viability, and environmental performance. Besides, the production cost, return on investment (ROI), and total emissions were $0.776 per liter of biodiesel, 334 %, and 0.08 kg CO2/kg of biodiesel, respectively.