Asphaltenes, subfractions A1 and A2 aggregation and adsorption onto RH-SiO2 nanoparticles: Solvent effect on the aggregate size

The aggregation and adsorption of asphaltenes in dilute solutions has been extensively studied is now well established. At low concentrations, are mainly found the form aggregates approximately 3 nm size. One strategy to simplify study these systems fractionate into subfractions called A1 A2. nature subfraction aggregates, their behavior with concentration interaction other surfaces remain under debate. This work presents experimental results on A2 onto SiO2 nanoparticles from rice husks (RH-SiO2), evidence allows us infer that equilibrium solution over a wide range concentrations. size distribution for each does not change dilution but sensitive solvent media. Subfraction very similar asphaltenes, while tends larger aggregates. Larger more likely adsorb than small According results, different solvents can be as phase phenomenon, where aggregate considered partially immiscible solvent. theoretical principles described, hypothesis elaborated terms.