Characterization of nanostructured rapeseed oil as an automotive biodiesel

Abstract

Nanoemulsions produced by the use of co-solvents show unexpected thermodynamic stability without the use of conventional surfactants. We study the system rapeseed oil – ethanol – 1-heptanol to be able to understand the effects of these nanoemulsions on biofuel properties. Ternary fuel blends prepared at a constant weight percentage of 20% 1-heptanol while varying the mass of ethanol and rapeseed oil and also at a constant weight percentage of 30% rapeseed oil while varying the mass of ethanol and 1-Heptanol were investigated for particle size, zeta potential and kinematic viscosity. The Particle sizes of the blends were determined by dynamic light scattering at 25OC. Complete nanoemulsions with droplet sizes of 92.29 nm and 47.76 nm were observed in the 2:3:3 and 2:4:4 (1-heptanol: ethanol: rapeseed oil) blends respectively. The kinematic viscosity of all blends prepared at 30% wt of rapeseed oil was between 2.67 – 5.6 mm2/s which met the ASTM D6751 biofuel standards. The improved kinematic viscosity of the blends could be attributed to the co-solvent behaviour of 1-heptanol on rapeseed oil and ethanol. Keywords— Biofuel, Co-solvent, Kinematic viscosity, Surfactant, Nanoemulsion.