Molecular dynamics simulation of organic contaminant adsorption on organic‐coated smectite clay
Molecular dynamics simulation of organic contaminant adsorption on organic‐coated smectite clay
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有机涂层蒙皂石粘土吸附有机污染物的分子动力学模拟
DOI：
10.1002/saj2.20364
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发表时间：
2022
影响因子：
2.9
通讯作者：
Bourg, Ian C.
中科院分区：
文献类型：
--
作者：
Willemsen, Jennifer A.;Emunah, Meléa;Bourg, Ian C.
分子动力学模拟用于检查酪氨酸和谷氨酸分子在三种不同有机负载下的一堆蒙脱石颗粒上的吸附和聚集。结果表明，蒙皂石表面对有机分子具有很强的亲和力，两性离子酪氨酸分子覆盖外表面（并在较小程度上进入层间区域），而带负电的谷氨酸分子通常位于粘土边缘位置附近，并与水性和配位 Ca 离子配位。其他模拟研究了酪氨酸和谷氨酸有机涂层对邻苯二甲酸二甲酯 (DMP) 和全氟丁磺酸 (PFBS) 两种有机污染物吸附的影响。这些涂层的添加并没有阻止 DMP 和 PFBS 分子进入先前确定的有利吸附域。吸附能量学分析表明，当酪氨酸和谷氨酸被引入系统时，相对于纯矿物表面，污染物吸附最初减少，随后随着有机负载的增加吸附增加。总体而言，这项研究推进了对蒙脱石表面、有机涂层和有机污染物之间相互作用的机理理解。
Molecular dynamics simulations are used to examine the adsorption and aggregation of tyrosine and glutamate molecules on a stack of smectite particles at three different organic loadings. The results reveal a strong affinity of the smectite surface for the organic molecules with the zwitterionic tyrosine molecules coating the exterior surfaces (and entering the interlayer region to a lesser extent), whereas the negatively charged glutamate molecules are generally found near the clay edge sites and in coordination with aqueous and coordinating Ca ions. Additional simulations examine the effects of the tyrosine and glutamate organic coatings on the adsorption of two organic contaminants, dimethyl phthalate (DMP) and perfluorobutanesulfonic acid (PFBS). The addition of these coatings did not prevent the DMP and PFBS molecules from accessing previously identified favorable adsorption domains. An analysis of the adsorption energetics shows an initial decrease in contaminant adsorption relative to pure mineral surfaces as tyrosine and glutamate are introduced to the system, followed by increasing adsorption with increasing organic loadings. Overall, this research advances the mechanistic understanding of the interplay between smectite surfaces, organic coatings, and organic contaminants.