Ultrasound-assisted transesterification of Moringa oleifera seed oil and the effect of operating conditions on biodiesel yield

Abstract

Moringa oleifera seed oil represents a promising feedstock for biodiesel production due to its availability, oil content, and oil and biodiesel properties. Biodiesel production assisted by ultrasound high-frequency and low power is more sustainable and thus proves to be an alternative way to produce biodiesel. In this work, the effects of reaction time and amplitude on the M. oleifera oil transesterification process assisted by ultrasound were evaluated. The reaction was carried out using an ultrasonication device Hielscher Model UP200S operated at 200 W and a frequency of 24 kHz. The physicochemical properties of the Moringa oleifera oil were in close agreement with previous reports while the derivate methyl esters meet the ASTM D6751 and EN 14214 standards. At relatively short reaction times (5-30 min), the methyl esters yield ranged from 82.38 to 94.30 %. The results indicated that the best condition of design of experiments was achieved for 50 % of amplitude and 30 min of reaction time, obtaining the highest methyl ester yield (93.54 %). Moreover, it was also demonstrated that an increase in reaction time such as 45 min did not produce a significantly higher conversion of Moringa oleifera methyl esters.