A Comprehensive Review of Biodiesel Production using Heterogeneous Catalyst

Abstract

Biodiesel, an eco-friendly alternative to petroleum diesel, is derived from vegetable oils or animal fats through transesterification. The use of heterogeneous catalysts, specifically titanium dioxide (TiO₂) and calcium oxide (CaO), in biodiesel production has garnered significant attention due to their environmental benefits and potential to replace fossil fuels. This study systematically analyses biodiesel production using TiO₂-CaO catalysts, highlighting their efficiency under various reaction conditions, catalyst preparation methods, and operational parameters. Different feedstocks, such as palm oil, cooking oils, and algal biomass, are evaluated. Methodologies reviewed include wet impregnation and photochemical techniques for catalyst synthesis, with varying reaction temperatures and times. The findings reveal that while TiO₂ and CaO have been extensively researched, the variation in methodologies hinders the development of standardized procedures like XRD, SEM, BET, and thermal analysis. Results indicate that cooking oil is a cost-effective feedstock, yielding biodiesel efficiently under optimal conditions: a methanol-to-oil ratio of 24:1, catalyst concentration of 5%, and reaction temperatures of 55-65 °C. The highest biodiesel yield of 98% was achieved using palm oil. Further studies should focus on optimizing and standardizing biodiesel production processes using the TiO₂-CaO catalyst.