Comparative study of synthetic and natural antioxidants on the oxidative stability of biodiesel from Tilapia oil

Abstract

A major obstacle in the commercialization of biodiesel is its susceptibility to oxidation when exposed to air and light. Approaches to improving the oxidative stability of biofuels include the addition of antioxidants, mixing of vegetable oils or modification of the fatty ester profile. This work aimed to evaluate the physicochemical properties of biodiesel synthesized from Tilapia oil and its oxidative degradation process after addition of both natural ethanolic extract of turmeric (Curcuma longa Linn.) and synthetics butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT), propyl gallate (PG) antioxidants. In addition, some thermodynamic and kinetic parameters were obtained in order to determine the activation energy during the biodiesel oxidation process from different temperatures. The physicochemical properties of biodiesel obtained after the addition of antioxidants are in accordance with current regulations, which suggests it as an excellent alternative source for the biofuel industry. The oxidative stability showed that the natural antioxidant has the best response in control of oxidative process compared to the other synthetic antioxidants. The kinetic study showed the addition of natural antioxidant to biodiesel increases the activation energy (Ea) hindering its oxidation process. These results reveal an improvement in biodiesel stability corresponding to an increase over 450%.