Density functional theory assessed molecular insights into asphaltene interactions within silica and calcium carbonate surface with deep eutectic solvents

Abstract

Deep Eutectic Solvents (DES) have gained recent attention as asphaltene solvents due to their low cost and eco-friendliness. However, identifying the intermolecular behavior of asphaltene with different DESs using experimental methods is costly and time-consuming. Therefore, this study investigates the intermolecular interactions and electronic properties of DESs with model asphaltene in the presence of sandstone (SiO2) and carbonate (CaCO3) surfaces using Density Functional Theory (DFT) calculations. The study focuses on understanding the binding energies, interaction energies, band gap, and intermolecular mechanism between SiO2 surface, asphaltene, and DESs (SiO2-Asp-DESs systems) and CaCO3 surface, asphaltene, and DESs (CaCO3-Asp-DESs systems). The investigation yields valuable insights into the interactions, stability, and affinity of the asphaltene and DES in the overall system, enhancing understanding of asphaltene behavior in solvent environments. The study shows that DES containing choline chloride as a hydrogen bond acceptor (HBA) outperforms in the presence of both surfaces (SiO2 and CaCO3) with asphaltene. For the SiO2-Asp-DES system, which contains DES as choline chloride and ethylene glycol, a higher intermolecular interaction energy of − 747.174 kJ/mol is observed. In contrast, for the CaCO3-Asp-DES system, DES as choline chloride and glycerol show higher intermolecular interaction energy of − 259.154 kJ/mol. Variations in interaction and binding energies for the systems further show that the effectiveness of DES with asphaltene varies depending on the type of surface (SiO2/CaCO3). As for the overall reactivity, CaCO3-Asp-DESs systems show comparatively less reactivity than SiO2-Asp-DESs systems that show smaller band gaps.