Agro-industrial waste and Moringa oleifera leaves as antioxidants for biodiesel

Biodiesel is a renewable fuel, thus is a sustainable option to minimize the environmental impacts of burning fossil fuels. However, biodiesel may suffer oxidative processes and is necessary to add antioxidants in it. In this study, macerated barley waste and Moringa oleifera leaves were used as antioxidants sources for biodiesel (soybean oil methyl ester). Accelerated oxidations studies, using 3(2) experimental design and employing the equipment Rancimat., were made and the best induction time found was 8.18 +/- 0.18 h, to concentrations of 13 and 9 g L-1 of waste and leaves, respectively. It was also established that oxidation kinetics follows a zero-order reaction (k = 7.28 x 10(-2) cm mu S-1 s(-1)), with an activation energy of 242.1 kJ mol(-1). Besides, at 25 degrees C the biodiesel produced under these conditions can be stored for about 6.5 months without quality losses due to oxidative processes. Thus, it is possible to use barley waste and moringa leaves as antioxidant sources for biodiesel.