Use of TiO ₂ Nanocatalyst for the Production of Biodiesel From Sewage Sludge

ABSTRACT Municipal sewage sludge of particle size below 425 µm has been utilized as the feedstock for biodiesel production. The moisture content in sewage sludge was found to be 81.7% for raw sewage sludge, and it was reduced to 20.7% after oven drying overnight at 60°C. Ash content was found to be 9.12% in the sludge. Titanium dioxide (TiO 2 ) was used as the heterogeneous nanocatalyst. The size of TiO 2 nanoparticles was found to be in the range of 80–150 nm, and the shape of the nanoparticles was spherical in nature. Different parametric studies of transesterification reactions, such as catalyst dose, reaction time, temperature, and methanol‐to‐solid ratio (MS ratio), have been done. Transesterification of sewage sludge was conducted in the presence of different catalyst doses, such as 0.5%, 1%, 3%, 5%, 7%, and 10%. The reaction was continued for 10, 20, 30, 40, 50, 60, 70, and 90 min. The optimum value of the catalyst dose was found to be 5%, and the reaction time was 30 min. Reaction was tested at different temperatures, such as 30°C, 40°C, 50°C, 60°C, 70°C, 90°C, and the optimum value was found to be 40°C. Different MS ratios were maintained: 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, and 60:1, and the optimum value was identified as 50:1. For quality determination of the biodiesel fuel properties, such as density, viscosity, flash point, fire point, aniline point, diesel index, and cetane number were also tested.