The geometry of phenanthridine, benzothiophene, tetralin, and naphthalene representative of the heterocyclic, naphthenic, and aromatic components of bitumen adsorbed on kaolinite is optimized using density functional theory and periodic boundary conditions in gas phase. These bitumen model compounds preferentially adsorb on the aluminum hydroxide surface of kaolinite with energy decreasing in the order phenanthridine > naphthalene > tetralin ∼ benzothiophene. The adsorption of phenanthridine is strengthened by hydrogen bonding between the pyridinic N atom and an axial hydroxyl group of kaolinite, while the rest of the molecules adsorb through van der Waals interactions. The mechanism of solvation in CO2 and the effect of liquid and supercritical CO2 on the adsorption thermodynamics are studied using the three-dimensional reference interaction site model theory with the closure approximation of Kovalenko and Hirata (3D-RISM-KH) molecular theory of solvation at 293–333 K and 10–30 MPa. The CO2 solvent inter...