INFLUENCE OF SURFACTIN ON INTERFACIAL BEHAVIOR AND ASPHALTENE AGGREGATION

Asphaltenes precipitation and deposition in porous media represents one of the primary challenges in reservoir engineering, as they lead to permeability and oil recovery decreasing, and alsowettability changes, among other. In this context, biosurfactants emerge as sustainable alternatives for mitigating these effects, since they show high interfacial activity, low toxicity, biodegradability, and high thermo and acid stabilities. The aim of this work was to investigated the interaction between asphaltenes and surfactin (biosurfactant), in particular as a precipitation inhibitor and correlating its effects with the interfacial and textural properties of asphaltene films. The interfacial behavior of the system was investigated using pendant drop tensiometry, Langmuir–Blodgett (LB) trough, and atomic force microscopy (AFM). Tensiometry allowed the evaluation of surfactin adsorption at the oil/water interface, while the Langmuir–Blodgett technique provided information on the organization and compressibility of interfacial monolayers. AFM was used to characterize the topography of the films formed. The results showed that surfactin significantly reduces interfacial tension, indicating strong adsorption and molecular reorganization of asphaltenes. AFM analyses revealed a reduction in the roughness of the films deposited in the presence of surfactin. Furthermore, the presence of surfactin induced structural cracks in LB films, evidencing the destabilization of intermolecular interactions. Therefore, the results indicated that surfactin influences the self-aggregation of asphaltenes, favoring the formation of more homogeneous films with a lower propensity for deposition.