Biodiesel potential of used vegetable oils transesterified with biological catalysts

Biodiesel has gained wide acceptance as an alternative energy source despite its high cost of production. This study investigated the possibility of lowering the cost of biodiesel production by exploring the use of readily available biological materials such as egg-shell (ES), pineapple peel (PP) and cow bone (CB) as catalysts. The effect of the refining process on the chemical properties of used vegetable oil was also examined. The refined oil was transesterified and biodiesel yield of 76%, 78% and 88.3% were obtained for ES, PP and CB catalyzed biodiesel samples, respectively. The three biodiesel samples were found to be of close physicochemical properties and good biodiesel potentials going by the ASTM and EN standards. It was also observed that the chemical properties such as the acid, free fatty acid and iodine value of the used vegetable oils greatly improved after the degumming process.