Recent Advances in Biowaste-Derived Bifunctional Catalysts in Biodiesel Production: A Mini-Review

There is a growing need for alternative energy sources due to rising concerns about global warming, the depletion of fossil fuels, and the consequences of particulates generated during their usage. In this regard, biodiesel serves as a renewable and comparatively clean alternative to fossil fuels because it is non-toxic, environmentally friendly, sustainable, biodegradable, and made from renewable sources like animal fats or edible/inedible oils. Additionally, it requires minimal modification to be used with the current fuel infrastructure when blended with petrodiesel. Animal fat or oil is (trans)esterified with a catalyst to produce biodiesel. Due to their improved adherence to the 12 Principles of Green Chemistry, solid catalysts are currently surpassing homogeneous catalysts. Besides, bifunctional solid catalysts are more highly desired than their monofunctionalized analogues because they can enhance product selectivity and make it easier for coordinated, one-pot processes to convert nonedible oils to biodiesel. The objective of this mini- review is to evaluate the developments in bio-waste-derived bifunctional catalysts for the synthesis of biodiesel from non-edible oils between 2019 to the present.