State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Research Institute of Safety & Environment Technology, China National Petroleum Corporation, Beijing, 102206, China.
Environ Sci Pollut Res Int. 2020 Jul;27(20):25754-25765. doi: 10.1007/s11356-020-09018-2. Epub 2020 Apr 30.
Humic acid (HA) and water play an important role in polycyclic aromatic hydrocarbons (PAHs) adsorption and biodegradation in soil. In this work, molecular dynamics (MD) and electrostatic potential surfaces (EPSs) simulations are conducted to research the contribution of quartz surface, leonardite humic acid (LHA), and water to PAH adsorption. The adsorption energies between PAHs and LHA are much higher than that between PAHs and quartz. Simulation shows that the hydroxyl and carboxyl groups' attraction by LHA is the main adsorption force between PAHs and LHA. The π-π interaction between PAHs and LHA also contributes to the adsorption process. In addition, the mobility of water on quartz surface is much higher than that of LHA. Water should be regarded as an adsorbate in the system as well as PAHs. However, the presence of water has a remarkable negative effect on the adsorption of PAHs on LHA and quartz. The bridging effect of water could only enhance the stability of the aggregation system. The adsorption contribution of quartz and LHA to PAHs in the soil model tends to 0 if the water layer reaches 2.0 nm. Graphical abstract.
腐殖酸（HA）和水在土壤中多环芳烃（PAHs）的吸附和生物降解中起着重要作用。在这项工作中，通过分子动力学（MD）和静电势能表面（EPS）模拟研究了石英表面、风化煤腐殖酸（LHA）和水对 PAH 吸附的贡献。PAHs 与 LHA 之间的吸附能远高于 PAHs 与石英之间的吸附能。模拟表明，LHA 中的羟基和羧基对 PAHs 的吸引力是 PAHs 与 LHA 之间的主要吸附力。PAHs 与 LHA 之间的π-π相互作用也有助于吸附过程。此外，水在石英表面上的迁移率远高于 LHA。水应该被视为系统中的吸附物以及 PAHs。然而，水的存在对 LHA 和石英上 PAHs 的吸附有显著的负面影响。水的桥接作用只能增强聚集体系的稳定性。如果水层达到 2.0nm，石英和 LHA 对土壤模型中 PAHs 的吸附贡献趋于 0。
