Feasibility of Using Tabagwang Waste Shells as Catalyst in the Production of Biodiesel from Yellow Grease

Heterogeneous catalytic transesterification of yellow grease, commonly known as used cooking oil, utilizing the calcium oxide derived from waste shells of Jagora asperata, locally known as tabagwang, was carried out to produce biodiesel. Waste tabagwang shells were prepared and calcined at 900°C for 4 hours under static air to obtain CaO. The prepared CaO was used as a catalyst in the transesterification of used cooking oil. Reaction conditions such as temperature (45°C and 60°C), catalyst loading (2% and 10%), and methanol-to-oil molar ratio (6:1 and 9:1) were considered to evaluate the feasibility of the catalyst in terms of percent yield. For the given set of parameters, the largest yield of 4.85 mL biodiesel, corresponding to 9.70%, was obtained at temperature of 45°C, catalyst loading of 2%, and methanol-to-oil ratio of 9:1. Using a two-level factorial design, an optimum yield of 10.06% was calculated with the following conditions: temperature, 47.06°C; catalyst loading, 2.03%; methanol-to-oil molar ratio, 8.93:1.