Experimental investigation of nano-additive enhanced Azolla biodiesel blends for improved diesel engine performance and emission mitigation

Abstract This study investigates the performance and emission characteristics of a diesel engine fueled with Azolla microphylla biodiesel blends and the effects of aluminium oxide (Al 2 O 3 ) and copper oxide (CuO) nanoparticles as fuel additives. Azolla microphylla, an aquatic fern, was used to produce biodiesel through a transesterification process. Diesel fuel was blended with Azolla biodiesel in ratios of 10:90 (B10), 20:80 (B20), and 30:70 (B30). Engine performance parameters, including brake thermal efficiency (BTE), brake-specific fuel consumption (BSFC), and emissions of carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and smoke, were evaluated. The results showed that the B30 blend exhibited the highest BTE under maximum load conditions. To address the high viscosity and poor combustion performance of higher biodiesel blends, Al 2 O 3 and CuO nanoparticles were added to the B30 blend at concentrations of 50 ppm and 100 ppm. The B30 blend with 100 ppm Al 2 O 3 nanoparticles demonstrated the highest BTE and the lowest emissions of HC, CO, CO 2 , and smoke compared to the other test blends. The improved combustion and reduced emissions were attributed to the enhanced heat transfer and catalytic properties of the Al 2 O 3 nanoparticles. These findings suggest that Azolla biodiesel, especially when combined with Al 2 O 3 nanoparticles, can be a viable and sustainable alternative to conventional diesel fuel.