Using of Natural Antioxidants (USM) Derived From Olive Oil Mill Waste to Improve the oxidative Stability of Biodiesel against Rancidity

Oily wastes are the waste that causes environmental pollution and severe damage to the aquatic life. However they have a great potential to be use as preservative (single or combined with synthetic ones) of Biodiesel. Biodiesel as an alternative diesel fuel obtained by transesterification of vegetable fats and oils, using alcohol in the presence of a catalyst, has some advantages such as reduced emissions of unburned hydrocarbons, carbon monoxide, sulfates, polycyclic aromatic hydrocarbons, but its drawback, of being more prone to oxidation than petroleum-based diesel fuel, can cause the fuel to become acidic (cause fuel system corrosion) and to form insoluble gums and sediments and consequently to increase its viscosity. In this study, in order to increase the stability of biodiesel based on high oleic acid sunflower oil against oxidation process during the storage and distribution, at the presence of natural antioxidants derived from either sewage of olive oil mill or olive oil, and synthetic antioxidant TBHQ. The stability was detected through rancimat test at 110 °C. The most effective biodiesel formulation in providing higher induction time is for the synergistic effect between natural and synthetic combination. The phenomena were followed and confirmed through FTIR analysis and PCA evaluation.