<p>The growing demand for cleaner and more sustainable fuels has driven significant research into biodiesel blends as viable alternatives to conventional diesel. This study explores the enhancement of combustion performance and emission characteristics of Mahua biodiesel (MB)–diesel blends through the incorporation of carbon-based nanoparticles and the use of electrostatic precipitators to suppress particulate matter emissions. The basic characterization of MB and the nanoparticles was conducted, and various volume concentrations of MB (10%, 20%, and 30%) were blended with neat diesel fuel (NDF). Additionally, the 30% MB–diesel blend was enriched with 100&#xa0;ppm of carbon nanotubes (CNTs). The test fuels were evaluated under varying brake power conditions. Results indicated that increasing MB concentration reduced brake thermal efficiency (BTE) by 10.3% and increased brake specific fuel consumption (BSFC) and nitrogen oxide (NOx) emissions by 16.3% and 5.2%, respectively. Meanwhile, hydrocarbon (HC) emissions, carbon monoxide (CO) emissions, and smoke opacity decreased by 12.4%, 6.4%, and 11.8%, respectively. The enrichment of CNTs in the biodiesel blend significantly improved combustion characteristics, resulting in a shorter ignition delay period and an increase in BTE by 4.9%. Furthermore, reductions of 6.3%, 10.5%, 10.8%, and 5.3% were recorded for NOx, HC, CO, and smoke opacity, respectively. In addition, the integration of an electrostatic precipitator at the engine exhaust effectively reduced particulate matter emissions by 62.9%. This combined approach demonstrates a significant improvement in the combustion efficiency and environmental performance of Mahua biodiesel blends, highlighting the potential of integrating nanotechnology and electrostatic solutions for sustainable energy applications.</p>