Potential application of supercritical extract of pomegranate peel as bio‐antioxidant for biodiesel

Abstract

AbstractThe performance of the pomegranate peel extract against the synthetic antioxidant additives on the oxidation stability of commercial biodiesel B100 derived from soybean was evaluated. The experimental extraction was conducted under 200 bar, 35, 45, and 55°C, and 0.0, 2.5, and 5.0 mL of ethanol as co‐solvent. Due to the rich in squalene and α‐tocopherol composition, all extracts presented high antioxidant capacity, 16.70 to 1.68 μg mL−1. In the oxidation stability tests, the addition of 1000 ppm of the supercritical extracts of pomegranate peel to biodiesel resulted in the increment of the induction time of pure biodiesel by up to 1.83. In contrast, the biodiesel added at 1000 ppm with commercial antioxidants increased the times up to 1.58 and 1.79, respectively for butylated hydroxyanisole and butylated hydroxytoluene. Biodiesel added with supercritical extract of pomegranate peel, obtained under 35°C and with 5.0 mL of ethanol, presented higher efficiency in the prevention of the oxidative process and was in accordance with norm European Standard EN 14214. The findings revealed that the extract is a promising natural antioxidant for biodiesel, that, besides being eco‐friendly, is an additive that can substitute commercial synthetic antioxidants, extending biodiesel stability.