Chemical characterization of oil and biodiesel from Common Purslane (Portulaca) seed as novel weed plant feedstock

Abstract

In this research, Portulaca seed oil was studied as a feedstock for biodiesel production. Portulaca is a type of weed that is able to grow in most weather conditions. The process of transesterification reaction for biodiesel production was optimized using the response surface methodology (RSM) method. Moreover, quadratic polynomial equations were obtained for the transesterification reaction. The ultrasonic system was employed to reduce the reaction time. The effects of independent variables such as catalyst concentration, reaction time and molar ratio of methanol-to-oil were studied. The reaction temperature was considered to be 55 °C. Also, the amplitude and the pulse of the ultrasonic system were 70% and 0.4 s, respectively. The results of the research indicated that all independent variables and their interaction have a significant effect on biodiesel yield. The highest biodiesel yield was 97.81% for the following optimum conditions: catalyst concentration of 1.01% (w/w), methanol: oil molar ratio of 8.49:1, reaction time of 8.01 min, temperature of 55 °C, pulse of 0.4 s, and an amplitude of 70%. Furthermore, all the measured physicochemical properties are in accordance with the ASTM standard. According to the obtained results, it can be concluded that Portulaca weed seeds are a suitable source for biodiesel production.