Abstract The adsorption and desorption of asphaltene on silica surface is highly dependent on the heteroatoms present in its structure. Herein, some model asphaltene molecules with different heteroatoms (i.e., N, O, S) at different positions (in the aromatic cores, in the middle and termination of alkane side chains) are selected as the adsorbates to investigate their adsorption and desorption behaviors on silica surface through molecular dynamics (MD) simulation. Results reveal that the characteristic adsorption configuration of asphaltenes is ascribed to the competition between the asphaltene-silica interaction and π–π stacking interaction among the asphaltene polyaromatic rings. The presence of heteroatoms is found to be able to strengthen the interactions between asphaltenes and silica, depending on their type and location. For example, the terminal polar groups, especially the carboxyl (COOH), exhibit the greatest contribution to the electrostatic interaction (increasing from −81 to −727 kJ/mol). The S atoms are also found to increase the van der Waals interaction energies by 25%. According to the equilibrium desorption conformation and density profile, the presence of heteroatoms is found to significantly hinder the desorption of asphaltenes from silica due to the enhanced polar interactions. The impeded desorption is also confirmed by the slower detachment of asphaltenes based on the time-dependent interaction energies and center of mass (COM) distances analysis. Additionally, the terminal polar groups lead to extraordinary desorption properties of asphaltenes. It is observed that the strong asphaltene-silica and asphaltene-water interactions coexist in these systems due to the high polarity and hydrophilicity of the terminal polar groups.

中文翻译：

---

N、O 和 S 杂原子对二氧化硅表面沥青质吸附和解吸的影响：分子动力学模拟

摘要 沥青质在二氧化硅表面的吸附和解吸高度依赖于其结构中存在的杂原子。在此，选择了一些在不同位置（芳香核中、烷烃侧链的中间和末端）具有不同杂原子（即 N、O、S）的模型沥青质分子作为吸附质，研究它们在不同位置的吸附和解吸行为。通过分子动力学 (MD) 模拟的二氧化硅表面。结果表明，沥青质的特征吸附构型归因于沥青质-二氧化硅相互作用和沥青质多环之间的π-π堆积相互作用之间的竞争。发现杂原子的存在能够加强沥青质和二氧化硅之间的相互作用，这取决于它们的类型和位置。例如，末端极性基团，尤其是羧基 (COOH)，对静电相互作用的贡献最大（从 -81 增加到 -727 kJ/mol）。还发现 S 原子使范德华相互作用能增加了 25%。根据平衡解吸构象和密度分布，发现杂原子的存在由于增强的极性相互作用而显着阻碍了沥青质从二氧化硅中解吸。基于时间相关的相互作用能量和质心 (COM) 距离分析，沥青质较慢的分离也证实了解吸受阻。此外，末端极性基团导致沥青质具有非凡的解吸性能。