Comprehensive review on application of various nanoparticles for the production of biodiesel

Abstract

ABSTRACT It is not a deniable fact that the incessant reduction of fossil fuel is terrible for most of us. It becomes vital to have access to other substitute resources. Biodiesel is known as a green fuel produced through a ‘transesterification’ process whereby oil (triglycerides) and methanol are used along with the support of homogeneous as well as heterogeneous catalysts. The usage of homogeneous catalysts results into obstacles such as; soap formation reaction, difficulties in separation of catalysts from the mixture as well as assured higher expense. To overcome these hurdles, various basic or acidic heterogeneous catalysts have been applied for biodiesel synthesis. But such catalysts have drawbacks like; mass transfer resistance, time consumption, fast deactivation, inefficiency of the catalytic process and most importantly a fact that cannot be neglected, they are hazardous for the environment. Nevertheless, these issues can be mitigated by employing nano-sized particles of metal oxides as catalysts. The synthesized nanoparticles with high specific surface area, catalytic activity and selectivity can solve most of such complications arising in the transesterification reaction. Nanoparticles can play an important role in enhancing the product quality and achieving optimal operating condition for such process. In this paper, efforts have been thru by the authors to provide an insight regarding the synthesis of biodiesel with the help of nanocatalysts that has been so far observed, analyzed and applied. Abbreviations: ASTM: American Society for Testing and Materials; BaO: Barium oxide; CaO: Calcium oxide; FAME: Fatty Acid Methyl Ester; FFA: Free Fatty Acid; H2SO4: Sulfuric Acid; HC: Hydrocarbons; HCl: hydrochloric acid; KL: Kraft Lignin; KOH: Potassium Hydroxide; LiO2: Lithium Oxide; MgO: Magnesium oxide; NaOH: Sodium Hydroxide; NOx: Nitrogen oxide; PAH: Polycyclic Aromatic Hydrocarbons; SDBS: Sodium Dodecyl Benzene Sulfonate; SrO: Strontium oxide; SWCNH: Single-Walled Carbon Nanohorn; TiO2: Titanium dioxide/Titania; UCO: Used Cooking Oil; ZrO2: Zirconium dioxide; ZnO: Zinc oxide.