Adsorptive Separation of Methanol鈥揂cetone on Isostructural Series of Metal鈥揙rganic Frameworks M-BTC (M = Ti, Fe, Cu, Co, Ru, Mo): A Computational Study of Adsorption Mechanisms and Metal-Substitution

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• 作者：Ying Wu ; Huiyong Chen ; Jing Xiao ; Defei Liu ; Zewei Liu ; Yu Qian ; Hongxia Xi
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：7
• 期：48
• 页码：26930-26940
• 全文大小：598K
• ISSN：1944-8252

文摘

The adsorptive separation properties of M-BTC isostructural series (M = Ti, Fe, Cu, Co, Ru, Mo) for methanol鈥揳cetone mixtures were investigated by using various computational procedures of grand canonical Monte Carlo simulations (GCMC), density functional theory (DFT), and ideal adsorbed solution theory (IAST), following with comprehensive understanding of adsorbate鈥搈etal interactions on the adsorptive separation behaviors. The obtained results showed that the single component adsorptions were driven by adsorbate鈥揻ramework interactions at low pressures and by framework structures at high pressures, among which the mass effects, electrostatics, and geometric accessibility of the metal sites also played roles. In the case of methanol-acetone separation, the selectivity of methanol on M-BTCs decreased with rising pressures due to the pressure-dependent separation mechanisms: the cooperative effects between methanol and acetone hindered the separation at low pressures, whereas the competitive effects of acetone further resulted in the lower selectivity at high pressures. Among these M-BTCs, Ti and Fe analogues exhibited the highest thermodynamic methanol/acetone selectivity, making them promising for adsorptive methanol/acetone separation processes. The investigation provides mechanistic insights on how the nature of metal centers affects the adsorption properties of MOFs, and will further promote the rational design of new MOF materials for effective gas mixture separation.