OPTIMIZATION OF BIODIESEL PRODUCTION FROM SWEET ORANGE SEED OIL USING A GREEN Cu-Mn/TiO₂ NANOCATALYST AND CENTRAL COMPOSITE DESIGN (CCD) TECHNIQUE

Biodiesel is a renewable alternative fuel derived from biological resources such as vegetable oils, animal fats, non-edible oils, algae, and other plant-based materials. In this study, orange seed oil was explored as a potential feedstock for biodiesel production using a green Cu-Mn/TiO₂ nanocatalyst within a Central Composite Design (CCD) optimization framework. The extracted oil was analyzed through standard physicochemical procedures, while the catalyst was synthesized via the coprecipitation method and characterized using FTIR, BET, XRD, and SEM techniques.The process achieved a maximum biodiesel yield of 97.14% under optimal reaction conditions: a methanol-to-oil molar ratio of 15:1, catalyst loading of 3.0 wt%, reaction temperature of 55 °C, and a duration of 60 minutes. Regression analysis yielded a high coefficient of determination (R² = 0.9926), confirming an excellent model fit with strong predictive reliability. All transesterification variables had a statistically significant influence on biodiesel yield (p < 0.0001). Furthermore, the physicochemical evaluation of orange seed oil confirmed its suitability as a biodiesel feedstock, while the resulting biodiesel produced biodiesel exhibits excellent conformity with ASTM D6751 standards demonstrating its potential for practical application.