The role of ionic liquid in asphaltene dissolution is studied using experimental characterization techniques, such as optical microscopic imaging analysis, 13C nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy, along with molecular insights achieved using classical molecular dynamics (MD) simulations. The dissolution behavior of the asphaltenes in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) ionic liquid along with organic solvents, i.e., toluene and hexane, is investigated using optical images. The behavior of asphaltene aggregates in the solvent plus ionic liquid mixture is probed using FTIR and 13C NMR spectroscopic techniques. The structural and dynamical properties of the asphaltene aggregates mainly end-to-end distance, the diffusion coefficient of the asphaltene molecules, and the trajectory density contour of the asphaltene in the solvent plus ionic liquid mixture are probed using MD simulations. It is concluded from our combined experimental-MD study that the ionic liquid plays a key role in asphaltene separation from organic solvents under study.

The aggregation behavior of asphaltene in the toluene-hexane mixture is systematically investigated using experimental techniques such as optical microscopy and Fourier-transform infrared spectroscopy (FTIR) combined with molecular dynamics (MD) simulations. The optical images of various asphaltene concentrations are processed to determine the size of asphaltene aggregates. FTIR is performed within our work in order to understand the formation of aggregates and its interaction with the solvent mixture. MD simulations are employed to achieve atomistic insights into the aggregation behavior of asphaltene. The end-to-end distance of the asphaltene molecule is calculated for various asphaltene concentrations in the toluene-hexane mixture. The dynamical properties of the asphaltene aggregates such as the diffusion coefficient and shear viscosity are calculated. Further, an in-depth analysis of the density contours is performed to probe the clusterization of asphaltene. Thus obtained structural and dynamical properties of the asphaltene aggregates in the toluene-hexane mixture are compared with our experimental findings. Our results thereby highlight the importance of the combined experimental and theoretical study to achieve deeper and better insights into the aggregation behavior of asphaltene in toluene-hexane mixture.

The aggregation behavior of asphaltene in aqueous solution is systematically investigated based on a classical molecular dynamics study. In this work, a novel approach is adopted in order to investigate the structural and dynamical properties of the asphaltene nanoaggregates using different water models. The end-to-end distance of the asphaltene molecule is probed in order to understand the aggregation behavior in aqueous solution. The accuracy of different water models, that is, simple point charge, TIP4P-D, and TIP5P, is thoroughly investigated. In order to probe the dynamical properties of the asphaltene nanoaggregates, the transport coefficients, namely, diffusion coefficient and shear viscosity, are computed. The obtained results highlight the importance of using the appropriate water model in order to accurately study the aggregation behavior of asphaltene in aqueous solution.