ABSTRACT
Concerns over energy security have led people, from ordinary individuals to politicians and scientists with different cultures and viewpoints, to find common ground for the last few decades. Despite the much effort that has been made to develop alternative energy sources, most nations are still heavily dependent on fossil fuels to meet their increasing energy demands. In this regard, replacing fossil-based fuels used in the transportation sector with renewable fuels such as biodiesel can help reduce countries’ dependence on non-renewable fuels and mitigate the adverse environmental impacts of fossil fuels such as gasoline and diesel. Due to its renewability, non-toxicity, biodegradability, and carbon neutrality, biodiesel has become a popular biofuel among scientific and industrial communities worldwide. However, homogeneous alkali-catalyzed transesterification used in most industrial plants for biodiesel production suffers from disadvantages such as high feedstock cost, prolonged reaction time, high energy consumption, and excessive wastewater production. Therefore, much research has recently been dedicated to finding an optimal, economically viable, and more environment-friendly process in terms of less expensive feedstock and advanced technologies with lower energy demand. This chapter reviews the recent advances in developing such a process, emphasizing the alternative feedstocks, catalysts, and conversion processes. The merits and drawbacks of each proposed raw material and production process were discussed in detail. Finally, some recommendations were presented for investigation in future studies to achieve a more efficient production process, considering both economic and environmental perspectives.
