Graphene oxide-doped marine microalgal biodiesel-diesel blends for enhanced performance and emission reduction in...

This study examines the performance and emission behavior of a diesel engine powered by blends of marine microalga biodiesel and conventional diesel fuel, further enhanced with graphene oxide (GO) nanoparticles. Biodiesel derived from Ulva fasciata was thoroughly characterized using FTIR, UV-Vis, GC-MS, and photoluminescence analysis, while GO was synthesized and confirmed through XRD and zeta potential studies (-44.6 mV), indicating excellent nanofluid stability. Among the tested B5 to B25 fuel blends, B25 showed the best baseline performance. Incorporating 55 ppm GO into the B25 blend decreased BSFC by 7%and increased brake power by 8%, with a peak torque of 13.5 Nm at full load. The GO-enhanced blend also decreased UHC, CO, NOx, PM, and smoke emissions, while a moderate rise in CO₂ suggested a thorough and efficient combustion process. These improvements can be credited to the superior thermal conductivity, extensive surface area, and oxygen-rich functional groups of GO, all of which facilitate more complete fuel oxidation and enhance heat transfer during combustion. The results demonstrate that GO microalgal biodiesel offers a suitable and efficient alternative to fossil diesel, aligning with global efforts toward low-carbon energy transition and cleaner transportation.