Hydronium-Promoted Equilibrium Mechanism for the Alkali Metal Cation Exchange Reaction in Na-4-Mica

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• 作者：Man Park ; Hong-Jin Kim ; Kwang Seop Kim ; Owen W. Duckworth ; Sridhar Komarneni
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：September 6, 2012
• 年：2012
• 卷：116
• 期：35
• 页码：18678-18683
• 全文大小：333K
• 年卷期：v.116,no.35(September 6, 2012)
• ISSN：1932-7455

文摘

A general stoichiometric cation exchange mechanism does not fully explain the unique exchange behaviors of Na-4-mica, the most highly charged swelling 2:1 phyllosilicate. Herein, we present for the first time a novel model of hydronium-promoted equilibrium for the cation exchange reaction of highly charged swelling 2:1 phyllosilicates with alkali metal cations. The exchange reaction of Na-4-mica with alkali metal cations revealed that adsorbed cations undergo further exchange with hydronium ions to result in the unprecedented back-release and position rearrangement of adsorbed cations. During the exchange reaction, hydronium ions play a key role as not competitive but stabilizing cation. Stabilization is accomplished through replacing half of the adsorbed cations and consequently relocating their position. Therefore, this hydronium-promoted equilibrium mechanism would provide a novel intellectual framework not only for understanding cation exchange reactions of various highly charged phyllosilicates but also for exploring their potential for new applications.