Production and Optimization of Biodiesel Using a Novel Cow Horn-Based Heterogeneous Catalyst.

The creation of sustainable substitutes like biodiesel is required due to the growing demand for energy worldwide and the harm that fossil fuels cause to the environment. This study aims to evaluate the catalytic efficiency of a novel cow horn-based heterogeneous catalyst in the optimization of biodiesel yield from waste cooking oil using Response Surface Methodology (RSM). The cow horn waste was processed into powder and calcined at 900°C for five hours to produce the bio-catalyst.A Central Composite Design (CCD) under Response Surface Methodology (RSM) was used to statistically optimize the production of biodiesel in a batch reactor. Thirty experimental runs that assessed four independent variables catalyst load (1.0–10.0 wt%), reaction time (30–150 min), reaction temperature (40–80°C), and a methanol-to-oil ratio (4:1 to 10:1) formed the basis of the optimization. The RSM model was statistically significant (p < 0.0001) and predicted a maximum biodiesel yield of 92.73% at the optimal conditions of 60°C, a 90-minute reaction time, a 5.5 wt% catalyst load, and a 7:1 methanol-to-oil ratio. However, the practical experiments failed to achieve this predicted yield. The primary constraint identified was the high Free Fatty Acid (FFA) content of the waste cooking oil, measured at 7.57%. It was concluded that while the cow horn-derived catalyst is a promising sustainable resource, it is not viable for the single-step transesterification of high-FFA waste cooking oil. The findings suggest that a prior acid-catalyzed esterification pre-treatment step is mandatory to reduce FFA levels before the cow horn-based catalyst can effectively facilitate the conversion process.