Storage and oxidation stability of commercial biodiesel using Moringa oleifera Lam as an antioxidant additive

Abstract

Herbal extracts have been studied due to the antioxidant property attributed to the phenolic compounds. The viability of biodiesel use is directly related to its stability. In this study the concentration of phenolic compounds of ethanoic extract of Moringa oleifera Lam leaf were determined and its antioxidant potential was evaluated by oxidative stability when used as an additive into biodiesel compared to the antioxidant effect of Butyl hydroxy toluene (BHT). The samples were stored in closed containers in the absence of light for 150days at temperatures ranged from 15 to 29°C and physicochemical analyzes such as viscosity, acid value and oxidative stability were performed regularly. The ethanolic extract showed a content of phenolic compounds of 24.89±1.00mg of gallic acid equivalent (GAE)/g extract. The oxidative stability results showed an increase in the induction period (IP) in biodiesel samples containing the extract, indicating a protective effect, inhibiting the oxidation initiation step. However, its action was less effective than the synthetic commercial additive BHT. A reduction in antioxidant potential for both the extract and for BHT was observed after one month of storage. It was also observed that the temperature is an important variable for maintaining the antioxidant properties. The results indicated the potential of Moringa oleifera Lam leaf extract as a natural antioxidant for biodiesel, with low toxicity that can ensure a safer consumption compared to synthetic antioxidants.