Green Synthesis of Lanthanum Oxide and Its Utilization in Modified Biodiesel for Optimal Performance and Exhaust Emissions of a Diesel Engine

The search for sustainable and efficient biofuels has led to the exploration of nanomaterial additives to enhance performance and reduce exhaust emissions. The present work aims at the synthesis of lanthanum oxide (La₂O₃) nanoparticles using the green hydrothermal route and their effects on the performance and emissions from the exhaust of a diesel engine powered with a 20% waste cooking oil (WCO) biodiesel blend (B20). A comparative analysis has been conducted to determine the optimal concentration, La₂O₃ (30 ppm and 40 ppm). Engine performance tests suggested that the incorporation of lanthanum oxide into waste cooking oil-biodiesel significantly enhanced brake thermal efficiency (BTE) from 23.79% for diesel to 25.95% and 26.02%, and the specific fuel consumption (SFC) decreased from 0.35 kg/kWh (diesel) to 0.22 kg/kWh and 0.21 kg/kWh for 30 ppm and 40 ppm, respectively. Further, the experimental examination of exhaust emissions indicates a reduction in hydrocarbon (HC) emissions from 68 ppm (diesel) to 67 ppm and 66 ppm. Carbon monoxide (CO) emissions reduced from 0.04% (diesel) to 0.0395% and 0.395%, while smoke opacity declined from 4.5–4.4% and 4.3% for 30 ppm and 40 ppm, respectively. But the nitrogen oxide (NOₓ) emissions are increased from 440 ppm (diesel) to 720 ppm and 689 ppm for the 30 ppm and 40 ppm dosages of La₂O₃, respectively. These findings from the present work suggest that synthesized (hydrothermally) La₂O₃ of 40 ppm dosage is a potential additive nanomaterial for improving a diesel engine’s performance and minimizing its exhaust emissions of diesel engine.