Abstract
The promising catalytic properties of calcium oxide from eggshell makes it desirable as a
heterogeneous catalyst for the production of biodiesel from waste oil. This study investigated the
effect of modifying plain calcium oxide from chicken eggshells on the transesterification of waste
vegetable oil to biodiesel. Using the American Standard Testing Methods (ASTM D6 751-03,
2003), acid value, free fatty acid, density, and viscosity analysis were performed on the waste
vegetable oil after cleaning. Free fatty acid reduction was done by esterifying the oil with 0.5wt%
tetraoxosulphate IV acid in a 1000ml round-bottomed flask. The round-bottomed flask was
mounted on a magnetic stirrer having a speed of 650rpm with the reaction temperature set to
60°C. Eggshell as parent catalyst was modified with zinc oxide and titania and the experiment
was performed at different catalyst loading. The biodiesel produced with different catalysts
modification and loadings was analyzed with Gas Chromatography-Mass Spectrometry. The free
fatty acid of the oil which was originally 6.875% was reduced to 2.404%. Also, a maximum
biodiesel yield of 75.52% was obtained with plain eggshell at 4wt% catalyst loading. The acid
value, density, viscosity, flash point, pour point, and cloud point of the biodiesel produced were
1.122mgKOH/g, 878kg/m3, 5.82cSt, 118°C, -1.1°C, and 1.7°C respectively.