Optimization of base catalytic transesterification toward maximum biodiesel yield from Azolla filiculoides macroalgae feedstock.

Since the current patterns of energy consumption are mostly dependent on fossil fuel, multiple issues related to energy resources, economic stability, and environmental pollution have arisen. Biodiesel is one of the potential alternative energy resources that can achieve sustainability. However, commercializing biodiesel is restricted with the high production costs that may not compete with the conventional diesel fuel since 70 – 95% of the costs are accounted for the raw materials. Azolla macroalgae is a potential source for fatty acids that can be a feedstock for commercial biodiesel. The current investigation took Azolla filiculoides as a feedstock to synthesize biodiesel. Soxhlet apparatus was the method of choice to extract the lipids which were subjected to the optimized transesterification reactions using response surface methodology (RSM). Four independent variables, which are oil to methanol molar ratio, catalyst loading, reaction temperature, and reaction time, were analyzed to optimize the highest response of biodiesel yield. 29 runs were suggested by the model. Actual experiments were conducted to validate the model. The obtained results were close to the predicted values with a reasonable error 0.029%. The best optimum value was 81.90% that was obtained at oil to methanol molar ratio 1:6, catalyst loading 1.75 wt%, reaction temperature 60 ◦C, and reaction time 120 min. The characteristics of the yielded fuel met the biodiesel standards of MS2008:2008, ASTM D6751, and EN 14214. Thus, Azolla filiculoides macroalgae are one of the promising feedstocks to produce commercial and sustainable biodiesel fuel. • Macroalgae Azolla filiculoides was utilized as a feedstock for biodiesel production. • 19.02% of lipids was extracted by Soxhlet. • The highest obtained biodiesel yield was 81.90%. • The physicochemical properties revealed compatibility with the biodiesel standards. [ABSTRACT FROM AUTHOR]