Comparative evaluation of base catalysts in biodiesel production from waste frying oil

The urgent need for alternative fuels has propelled biodiesel research into the spotlight, particularly focusing on cost-effective and sustainable feedstocks such as waste frying oil. This study investigates the technical and practical impact of four different base catalysts (NaOH, KOH, K₂CO₃, and Ca(OCH₃)₂) on the transesterification efficiency of waste frying oil. Experimental trials were systematically conducted by altering catalyst concentration and methanol-to-oil molar ratios to determine optimal production conditions. Statistical analyses confirmed that all process parameters had a significant impact on the biodiesel yield. Technically, NaOH and KOH yielded the highest conversion rates, while K₂CO₃ showed markedly lower performance. The study supports the process's cost-effective goal by demonstrating that NaOH and KOH, which provided the highest yields, are also the most economical and practical options due to their low cost and industrial availability. The developed multiple linear regression model affirmed the collective influence of the examined parameters with a strong predictive capability (R² = 0.933). Ultimately, this work highlights both the technical superiority and economic practicality of strong bases, particularly NaOH and KOH, for efficient biodiesel synthesis from waste frying oil, contributing to optimized processes that support the transition to greener energy alternatives.