Enhancing oxidative stability of biodiesel samples subjected to cations contamination during storage using Lantana camara L. (Verbanaceae) leaves extracts

The highest total phenolic contents 46.50 mg GAL/g dry weight (DW), total flavonoids (16.06 mg catechin/g DW), DPPH radical scavenging activity (87.69%) and reducing power activity (2.90, absorbance value) were recorded for aqueous ethanol (ethanol:water, 80:20 v/v) extract. The peroxide values of biodiesel samples subjected to 1000 and 2000 ppm of Fe3+, Cu2+ and Al3+ contamination at the end of the storage period (12 day) were about (1.45;1.96), (1.27;1.61) and (1.21;1.52) times as high as in control sample without additives, respectively. Biodiesel samples subjected to 2000 ppm of Cu2+ and Fe3+ had the highest values of p-AV (17.89 and 16.37) and Totox (92.98 and 85.23) at the end of the storage period, respectively. Addition of LCL extract at level of 800 ppm caused decreases in the formation of peroxide ranged from 53.48 to 66.00%, in the formation of secondary oxidation products from 47.58 to 69.64% and in Totox values varied from 54.56 to 66.25% compared to those samples subjected to metal contamination without antioxidant.