Current advances and future outlook of heterogeneous catalytic transesterification towards biodiesel production from waste cooking oil

Abstract

The judicious utilization of waste cooking oil (WCO) could be a viable option to curtail the production cost of biodiesel and mitigate the environmental issues related to waste disposal in landfills. The use of heterogeneous catalysts in biodiesel synthesis has been advocated as the most promising approach in recent years owing to their non-corrosive and easily separable nature and long catalytic life for recycling. However, WCO-derived biodiesel production by catalytic heterogeneous transesterification in large-scale industries is a barrier yet. Currently the majority of review articles emphasize on the progress of reactor configuration, and preparation of new catalyst based on the modifications of the catalyst's morphology. Concurrently, the synthesis of cost-competitive catalysts is also crucial for their commercial implementation. It is observed from a meticulous literature review that most of the catalysts used in biodiesel production are confined to the lab scale. For example, the synthesis of nanocatalysts is now an emerging area in biodiesel production, but practically it has not been feasible to use on a large scale. Therefore, biodiesel process development including cost effective heterogeneous catalysts is the need of the hour for its commercialization. In this paper, an integrated reactor design has been proposed for the heterogeneous catalytic transesterification process for biodiesel production towards commercial productivity and economic viability. Life cycle assessment of WCO-derived biodiesel production methods is also discussed. The efficiency and limitations of heterogeneous catalysts are summarized and compared in detail to assess their suitability in pragmatic applications with critical, theoretical, and scientific views. The present-day challenges and future outlooks are envisioned too.