Atomistic Prediction of Sorption Free Energies of Cationic Aromatic Amines on Montmorillonite: A Linear Interaction Energy Method

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• 作者：Milinda Samaraweera ; William Jolin ; Dharni Vasudevan ; Allison A. MacKay ; Jos茅 A. Gasc贸n
• 刊名：Environmental Science & Technology Letters
• 出版年：2014
• 出版时间：June 10, 2014
• 年：2014
• 卷：1
• 期：6
• 页码：284-289
• 全文大小：270K
• 年卷期：v.1,no.6(June 10, 2014)

文摘

Molecular dynamics (MD) simulations were performed to calculate free energies of sorption (螖G_sorb) of cationic aromatic amines to Ca-montmorillonite. We applied the linear interaction energy (LIE) method, well-established in the biochemistry field, to derive 螖G_sorb. We obtained a mean average error of 0.3 kcal mol^鈥? within the compound training set and an error of 0.41 kcal mol^鈥? for a validation test set. We were able to reproduce absolute 螖G_sorb values for a variety of compound structures, including the zwitterionic antibiotic oxytetracycline. MD simulations also provided atomistic level insights into the underlying driving forces that modulate sorption. Importantly, our approach provides a compelling alternative to polyparameter linear free energy relationship methods, which have shown limited success in capturing the sorption of ionogenic compounds with polar and/or charged moieties. We conclude that the LIE method can be used as a robust and tractable method to predict 螖G_sorb within families of organic cations bound to aluminosilicate clay minerals.