Particle—fluid interactions with application to solid-stabilized emulsions part I. The effect of asphaltene adsorption

Abstract Solid-stabilized water-in-oil emulsions are commonly encountered in the production of crude oil and synthetic fuel liquids. The ability of finely divided solids to stabilize these emulsions is due to the adsorption of asphaltenes and other heavy ends from the oil on the mineral surface which imparts to the solid its hydrophobic nature. This study presents results which quantify the particle—fluid interactions by means of adsorption measurements of asphaltenes on sodium montmorillonite particles. The influence of asphaltene adsorption on the contact angle at the water/oil/solid interface and on the zeta potential of the particles was investigated. The hydrophobic nature of the solids was found to be directly related to the amount of asphaltenes adsorbed on their surface. The effect of asphaltenes on the contact angle is explained in terms of the interfacial tensions at the oil/water and solid/water interfaces. The influence of pH and surfactant concentration in the aqueous phase on the contact angle and the zeta potential is assessed.