Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, Yunnan, China.
Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming, 650500, Yunnan, China.
Chemosphere. 2022 Sep;302:134772. doi: 10.1016/j.chemosphere.2022.134772. Epub 2022 May 5.
Polycyclic aromatic hydrocarbons (PAHs) are one of the most frequently detected hydrophobic organic contaminants (HOCs) in the environment. They may form clusters because of the strong hydrophobic and π-π electron-donor-acceptor (EDA) interactions among PAHs molecules. However, previous experimental studies and theoretical simulations generally ignored the impact of molecular clusters on the adsorption, which may result in the misunderstanding of the environmental fate and risk. In this work, naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) were selected to investigate intermolecular interaction as well as the consequent impact on their adsorption on graphene. The density field of C atoms in equilibrium configurations of self-interacted PAHs suggested that the formation of PAHs molecular clusters was a spontaneous process, and was favored in solvents with stronger polarity and for PAHs with more benzene rings. It should be noted that the molecular dynamics simulations with the initial state of molecular clusters matched better with the published experimental results compared with those of individual PAHs. The formed compact PAHs clusters in polar solvents increased the apparent PAHs adsorption, because of their higher hydrophobic and π-π EDA interactions. This study emphasized that the self-interaction of PAHs should be carefully considered in both experimental and theoretical simulation studies.
多环芳烃（PAHs）是环境中最常检测到的疏水性有机污染物（HOCs）之一。由于 PAHs 分子之间存在强烈的疏水性和π-π 供体-受体（EDA）相互作用，它们可能会形成聚集体。然而，以前的实验研究和理论模拟通常忽略了分子聚集体对吸附的影响，这可能导致对环境归宿和风险的误解。在这项工作中，选择萘（NAP）、菲（PHE）和芘（PYR）来研究分子间相互作用以及它们对石墨烯吸附的后续影响。平衡构型中 C 原子的密度场表明，PAHs 分子聚集体的形成是一个自发过程，在极性更强的溶剂中和苯环更多的 PAHs 中更有利。值得注意的是，与单个 PAHs 相比，具有初始状态为分子聚集体的分子动力学模拟与已发表的实验结果更吻合。在极性溶剂中形成的紧密的 PAHs 聚集体增加了表观 PAHs 吸附，因为它们具有更高的疏水性和π-π EDA 相互作用。这项研究强调，在实验和理论模拟研究中都应仔细考虑 PAHs 的自相互作用。
