Production of Biodiesel from Candlenut Oil Using Catalyst Variations (KOH and ZnO) Through the Transesterification Method

The global reliance on fossil-based energy sources such as petroleum, natural gas, and coal— characterized as non-renewable—is leading to their rapid depletion. In response, renewable fuels have emerged as sustainable alternatives, primarily derived from biological sources such as plants and animals. Catalysts play a vital role in both fossil and renewable fuel production by accelerating chemical reactions. This study investigates the production of biodiesel (methyl ester) from candlenut oil using potassium hydroxide (KOH) and zinc oxide (ZnO) as catalysts via a transesterification process conducted for one hour. A total of 16 biodiesel samples were synthesized with varying catalyst types and concentrations. The samples were characterized based on density, viscosity, calorific value, flash point, and compound identification via gas chromatography– mass spectrometry (GC-MS). The optimal result was achieved using a combination of 1% KOH and 1% ZnO catalysts with a methanol-to-oil molar ratio of 1:6. The biodiesel produced exhibited a flash point of 188°C and a calorific value of 9000.60 cal/g for the KOH-based sample, and a flash point of 181°C with a calorific value of 8223.60 cal/g for the ZnO-based sample. GC-MS analysis indicated a methyl ester content of 93.23% in the ZnO-catalyzed biodiesel, confirming its high purity and potential suitability as a diesel substitute.