Oxidation stability of biodiesel derived from waste catfish oil

Abstract

The present work investigates the properties and oxidation stabilities of biodiesel derived from catfish oil (B100 CFO) generated by the fish processing plants in Vietnam. The composition and physicochemical properties of the B100 CFO were measured, including oxygen content (~11 wt%), viscosity (4.5306 mm² -s⁻¹), density (0.8772 g cm⁻³), peroxide value (28.13 mg kg⁻¹), heat of combustion (39.18 MJ kg⁻¹), and acid number (0.12 mg KOH g⁻¹). Methyl oleate (46.44 wt%) was the dominant fatty acid methyl ester. B100 CFO was found to have poorer low-temperature quality than most vegetable oil derived biodiesels as determined by its fusion and crystallization properties. Novel modified ASTM D5304 and D2274 tests were employed to study the oxidation process of B100 CFO and the impact of oxidation time on its stability. Under ASTM 5304 test conditions, rapid O₂ consumption by B100 CFO occurred after 8 h, behavior similar to commercial biodiesel stabilized with antioxidant additives. The influence of oxidation condition and time on the B100 CFO physicochemical properties and low-temperature qualities was also investigated according to ASTM methods. Three oxidation stages were identified in B100 CFO based on the peroxide value change during the modified ASTM D5304 and D2274 tests. B100 CFO was also found have superior oxidation stability in comparison with B100 derived from waste cooking oil. This is the first report on oxidation stability of B100 derived from catfish oil.