Comparison of catalysts types performance in the generation of sustainable biodiesel via transesterification of various oil sources: a review study

Biodiesel, which is a favorable substitute fuel for conventional diesel, has lately drawn researchers' lookout because of its non-toxicity, sustainability, and reducing greenhouse gases. This green fuel can be generated using the transesterification process in the attendance of an efficient catalyst. Prior studies demonstrate that more than 35% of the prevalent expense of biodiesel synthesis is dependent on catalysts. In this direction, appropriate and efficient catalyst choice for transesterification reaction is of considerable significance. Hence, this paper aims at furnishing a summary of biodiesel synthesis via esterification and/or transesterification using various acid/alkaline catalysts, i.e. homogeneous and heterogeneous catalysts. Moreover, the potential of various catalysts in biodiesel production and their effect on the transesterification condition are considered. Besides, discussion on the catalyst characterization with some explanations was presented to improve the scientific aspect. Ultimately, the kinetic actual mechanism of biodiesel generation utilizing heterogeneous catalysts is also discussed. ✓ Performance, mechanism and stability of catalysts on biodiesel yield were studied. ✓ Possibility of gentler operating situations using nanocatalysts compared to other catalysts. ✓ Considerable biodiesel yield can be acquired using nanocatalysts. ✓ solid catalysts and their derivatives are the best alternatives to homogeneous catalysts. ✓ The use of biomass and waste materials can be a good alternative to synthetic catalysts.