In this study, it is reported the fractal dimension and morphology of ultrafine particles emitted by a diesel engine run with B4, B50, and B100. Transmission electron micrographs evidenced two main groups of particles with characteristic and distinct morphological behaviors: ( i ) particle agglomerate structures self-organized within a fractal-like geometry, and ( ii ) amorphous and irregular particles with diffuse edges in a liquid-like particle appearance, mainly associated with some sub-fractions of samples collected from B50 and B100 combustion. Particles from ( i ) showed typical diesel soot morphology and fractal dimension. Primary particle diameter (D pp ) was 24 ?± 4 nm, 23 ?± 4 nm, and 20 ?± 4 nm for B4, B50, and B100, respectively. Mean aggregate gyration diameters (D g ) ranged from 242 ?± 140 nm for B4, 210 ?± 135 nm for B50, and to 232 ?± 140 nm for B100. In turn, fractal dimensions (D f ) were 1.94, 1.89, and 1.99 for B4, B50, and B100, respectively. On the other hand, particle from ( ii ) had their morphology impaired from the addition of biodiesel to petrodiesel in a way it did not follow a fractal geometry.
展开▼
