Lab-scale catalytic production of biodiesel from waste cooking oil - a review

The adverse effects of fossil fuels on the environment and the rapid exhaustion of oil reserves are major concerns in the current global energy demand scenario. As a result, biofuels have emerged as promising alternate fuel due to their renewability, clean emissions and economic advantages over petroleum diesel. Biofuels are obtained from renewable sources such as vegetable oils, animal fat, microalgae, etc. Amongst these, waste cooking oil is considered to be an economical feedstock. This review focuses on different pretreatment methods for waste cooking oil and its lab-scale catalytic transesterification to biodiesel. Homogeneous, heterogeneous and enzymatic catalysts are compared based on reaction conditions, method employed and product yield. The purification steps, biodiesel properties and engine emissions profile are also discussed.