Low-emission nano-fuels from chicken fat waste: Performance and environmental impact assessment in CI engines

• BTE improved by 2.98 % using TiO 2 nano fuel over pure BCFW biodiesel. • TiO 2 blend reduced NOx emissions by 21.90 % compared to diesel. • Hydrocarbon emissions dropped 34.90 % with TiO 2 -based nano fuel. • Smoke opacity reduced by 19.83 % with TiO 2 nano additive. • Study supported sustainable fuel use from poultry industry waste. Valorizing waste resources into alternative fuels is a key strategy for promoting environmental sustainability and energy efficiency. Chicken fat waste, an abundant byproduct of the poultry industry, can be converted into biodiesel (BCFW) via transesterification and used as a renewable fuel for Compression Ignition (CI) engines. However, performance limitations and increased emissions hinder its direct use. This study aims to optimize the fuel blend by blending BCFW with diesel (50:50) and introducing 100 ppm of Silicon Dioxide (SiO₂), Titanium Dioxide (TiO₂), and Multi-Walled Carbon Nanotube (MWCNT) nanoparticles to formulate nano-fuels. Experimental evaluations were conducted across various power levels in a CI engine , assessing brake thermal efficiency (BTE), fuel combustion characteristics, and exhaust emissions . Results indicate that the SiO₂-based nano fuel exhibited a 1.11 % increase in BTE but led to 35.24 % higher NOx emissions due to enhanced oxidation. Conversely, the TiO₂-based nano fuel demonstrated the most favourable emission reductions, achieving 21.90 % lower NOx, 34.90 % lower HC, and 19.83 % lower smoke emissions than diesel, and improved BTE by 2.98 % over BCFW. The findings reveal that TiO₂-based nano fuel is an optimal low-emission alternative, balancing performance enhancement and environmental impact . This study contributes to sustainable fuel development, nanotechnology applications in combustion, and advancing renewable energy solutions for CI engines .