Durian shell, a biomass waste, was simply burned and then could serve as a heterogeneous catalyst for the transesterification reaction of palm oil with methanol at room temperature. The chemical composition, structure, and morphology of the catalyst were well-characterized by XRD, BET, SEM, TEM, EDS, TGA, FT-IR, and XPS measurement. With the preparation temperature rising to 350 °C, the maximum yield of the biodiesel could reach 94.1% at room temperature, and the optimum reaction conditions were 8 wt.% catalyst, 8:1 methanol/oil molar ratio, ad 2.5 h reaction time. The characterizations results indicated that K2O and K2CO3 existed on the surface of catalyst, and a moderate amount of carbon, which acts as a carrier, attributed to the activity of the catalyst. After repeating five times, the catalyst prepared at 350 °C showed better stability than other catalysts. This might be because the incomplete combustion of the remaining carbon slowed down the loss of K to some extent.
Keywords: biodiesel; durian shell; heterogeneous; transesterification; waste biomass.