The role of water in the elastic properties of aluminosilicate zeolites: DFT investigation

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• 作者：Ilya A. Bryukhanov ; Andrey A. Rybakov ; Alexander V. Larin…
• 关键词：Water ; Elastic properties ; Bulk modulus ; Young modulus ; Aluminosilicate zeolites ; DFT
• 刊名：Journal of Molecular Modeling
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：23
• 期：3
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Computer Applications in Chemistry; Molecular Medicine; Computer Appl. in Life Sciences; Characterization and Evaluation of Materials; Theoretical and Computational Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：0948-5023
• 卷排序：23

文摘

The bulk and Young moduli and heats of hydration have been calculated at the DFT level for fully optimized models of all-siliceous and cationic zeolites with and without water, and then compared to the corresponding experimental data. Upon the addition of water, the monovalent alkali ion and divalent alkaline earth ion exchanged zeolites presented opposite trends in the elastic modulus. The main contribution to the decrease in the elastic modulus of the alkali ion exchanged zeolites appeared to be a shift of cations from the framework oxygen atoms upon water addition, with the coordination number often remaining the same. The contrasting increase in elastic modulus observed for the divalent (alkaline earth) ion exchanged zeolites was explained by cation stabilization resulting from increased coordination, which cannot be achieved within a rigid zeolite framework without water.