Molecular-Level Investigation of the Adsorption Mechanisms of Toluene and Aniline on Natural and Organically Modified Montmorillonite

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• 作者：Xin-Juan Hou ; Huiquan Li ; Peng He ; Shaopeng Li ; Qinfu Liu
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：November 12, 2015
• 年：2015
• 卷：119
• 期：45
• 页码：11199-11207
• 全文大小：662K
• ISSN：1520-5215

文摘

The present work reports the adsorption mechanisms of aniline and toluene in dry and hydrated montmorillonite (MMT鈥揘a and MMT鈥揘a鈥揥) and tetramethylammonium-cation-modified MMT (MMT鈥揟MA) as determined through density functional theory. These theoretical investigations explicitly demonstrate that cation鈭捪€ interactions between Na⁺/TMA⁺ cations and aromatics play the key role in adsorption of organics over MMT鈥揘a and MMT鈥揟MA. Weak hydrogen bonds between the H atoms of organics and basal O atoms of tetrahedral silicate also stabilize the location of organics. The combination of interactions between water and basal O atoms and between organics and water molecules in hydrated MMT complexes strengthens the adsorption of organics on MMT, resulting in higher formation energies in hydrated organically intercalated MMTs than in the corresponding dry complexes. The adsorption of organics also changes frontier orbital distributions and consequently promotes the preferential occurrence of reactions on the organics rather than on the MMT layers. These adsorption mechanisms predicted by theoretical investigation can be used to explicate the adsorption of aromatic organics on aluminosilicates with different external environment.