Rice husk-based catalyst for sustainable biodiesel production: A meta-analysis and systematic review

Biodiesel continues to attract attention as a sustainable alternative to fossil fuels. This review focuses on the utilization of rice husk, an abundant agro-industrial waste as a heterogeneous catalyst for biodiesel synthesis. Critical process parameters including reaction temperature, calcination temperature, type of catalyst, agro-industrial waste type, biomass amount and surface area were systematically reviewed using the PRISMA method and statistically evaluated through PROC MIXED. Results show that rice husk-derived metal oxide catalyst achieved higher biodiesel yields (85.4 %) compared to organic composites catalyst (78.2 %). Optimization results further indicated an average conversion rate of 92.3 % under ideal conditions: 65 °C reaction temperature, 1.5 h reaction time and 3 wt% catalyst concentration. A statistically significant correlation was observed between catalyst type and biodiesel yield (p < 0.01). This review highlights the potential of rice husk-derived catalysts to enhance biodiesel production through waste valorization.