Biodiesel from high‐acid‐value grease trap waste: process optimization and purification using bio‐based adsorbent

Abstract

AbstractMaterial with negative value such as grease trap waste appears to be a cost‐effective feedstock for biodiesel production since it can be collected at little to no charge. Owing to its high lipid content, fatty acid methyl ester can be produced from grease trap waste via a two‐step production process with methanol, using potassium hydroxide as the catalyst. However, there are several process parameters that could affect the yield of the fatty acid methyl ester produced. In this study, the optimum conditions for biodiesel production were 6:1 methanol‐to‐oil molar ratio, 1.5 wt% potassium hydroxide loadings, a 40 °C reaction temperature and a 2 h reaction time, resulting in a fatty acid methyl ester yield of 87%. Further purification using 0.05 g L−1 of biobased adsorbent from woodchip biomass for a 1 h residence time at 25 °C yielded the highest removal of free fatty acid and soap at 98.2 and 67.9%, respectively. This study not only demonstrates the potential of grease trap waste as a bioresource for the production of biodiesel, but also proves an interesting and additional use of bio‐based adsorbent from woodchip biomass as an effective tool in biodiesel purification since the quality of biodiesel produced within the standard EN14214. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.