Interatomic Interactions in the Adsorption of Asphaltenes and Resins on Kaolinite Calculated by Molecular Dynamics

Molecular dynamics calculations of the energy of interaction of model asphaltene and resins on neutral surfaces of kaolinite in a vacuum showed that the van der Waals interaction provides the largest contribution (60−70%), with a smaller one (30−20%) from the Coulombic interaction. The H bonds provided 10% or less of the energy of interaction in the adsorption of these fractions onto kaolinite. It was found that the variations in the polarity of the resin introduced only minor changes in the energy of interaction with the surfaces. It was also determined that the resin interacts more strongly with the surfaces of kaolinite than with the asphaltene molecule, indicating that these surfaces may perturb the aggregates formed by the organic molecules that are found in crude oil.