The pomelo peel biochar catalysts and methanol were used for thetransesterification of palm oil in a three-neck, round-bottom flaskequipped with a thermometer, condenser, and magnetic heatingmantle. The transesterification reaction was represented as:The mixture was incubated at 65 °C with continuous stirring at800 rpm at atmospheric pressure. As reaction completed, the catalystwas removed from the mixture by centrifugation. The filtrate was keptin the funnel separator for 24 h. The top layer was evaporated by arotary evaporator under reduced pressure to eliminate excessive me-thanol. The biodiesel (fatty acids methyl ester, FAME) was analyzed bygas chromatography.