Application of nanomaterials for emission reduction from diesel engines powered with waste cooking oil biodiesel

Diesel engines that predominantly run on fossil-based diesel fuel emit harmful emissions. Biofuels such as biogas and biodiesel are potential alternatives. However, many biofuels have poor heating values and supply inconsistencies. The use of nanoparticles (NPs) offers an appealing alternative for enhancing the combustion and emission reduction. This study aimed to improve the emission performance of biodiesel produced from waste cooking oil biodiesel (WCOB) by adding titanium oxide (TiO2) NPs. Tests were conducted in the diesel-powered engine at varying load levels using fuel mixtures of B1 (100% diesel), B2 (80% diesel + 20% WCOB) and B3 (80% diesel + 20% WCOB with the addition of 200 mg/l TiO2 NPs). In comparison with the diesel mode, the average reduction in carbon monoxide emissions was 8.92% for the B2 blend and 25% for the TiO2 NP-based B3 blend. For the B2 blend and TiO2-based B3 blend, the mean reduction in hydrocarbon emissions was 5.6 and 16.6%, respectively, when compared with diesel mode. When comparing B3 blends with B2 blends, the average reduction in nitrogen oxide emissions was 3.75%. In conclusion, adding NPs to engine fuel is a viable solution for reducing emissions.