Assessment of biodegradability and oxidation stability of mineral, vegetable and synthetic oil samples

This study proposes to evaluate rapid methodologies to estimate oxidative stability and biodegradability for mineral, vegetable and synthetic oil samples, using quick and simple experiments. The synthetic oil sample was obtained from castor oil, so the vegetable oil chosen for this evaluation was a sample of the crude castor oil source. The oxidative stability tests described enabled the comparison of synthetic lubricant samples and showed that their stability was lower than that of petroleum-based oil. However, the physico-chemical properties, such pour points and viscosity index, were improved and potentially interesting for lubricant applications. The biodegradability experiments were carried out using a model of bio-kinetics. These studies proved that synthetic lubricant samples were easily degradable (similar to crude castor oil) and showed half-life significantly lower than those of the mineral oil samples.

Research highlights▶ Novel rapid methodologies used to evaluate oxidative stability and biodegradability. ▶ Oxidative stability of synthetic lubricant is higher than castor oil. ▶ Oxidative stability of synthetic lubricant is lower than mineral oil. ▶ Half-life of synthetic lubricant is considerably lower than mineral oil.