Conversion of Scenedesmus rubescens Lipid into Biodiesel by Biochar of Different Origin

One of the most recent applications studied in recent years is the use of biochar as a catalyst for the conversion of oils into biodiesel. The scope of this work was to evaluate the efficiency of biochars as heterogeneous catalysts for the conversion of Scenedesmus rubescens lipids into biodiesel. Biochar from different materials were employed, namely, malt spent rootlets (MSR), coffee spent grounds (CSG), and olive kernels (OK). Materials were charred at two temperatures (400 and 850 °C) in order to examine the effect of pyrolysis temperature. Homogeneous catalysts such as sulfuric acid and sodium hydroxide were also employed for comparison purposes. In order to explain the different performance of biochar as catalyst, we conducted detailed characterization of these materials. The results of this study showed that homogeneous catalysts (H2SO4 and NaOH) had similar results to the CSG biochar at 400 °C, which was the most productive tested biochar. The pyrolysis temperatures affected the FAMEs recovery of OK and CSG biochar.