Seawater Pervaporation through Zeolitic Imidazolate Framework Membranes: Atomistic Simulation Study

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• 作者：Krishna M. Gupta ; Zhiwei Qiao ; Kang Zhang ; Jianwen Jiang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：June 1, 2016
• 年：2016
• 卷：8
• 期：21
• 页码：13392-13399
• 全文大小：582K
• 年卷期：0
• ISSN：1944-8252

文摘

An atomistic simulation study is reported for seawater pervaporation through five zeolitic imidazolate framework (ZIF) membranes including ZIF-8, -93, -95, -97, and -100. Salt rejection in the five ZIFs is predicted to be 100%. With the largest aperture, ZIF-100 possesses the highest water permeability of 5 × 10^–4 kg m/(m² h bar), which is substantially higher compared to commercial reverse osmosis membranes, as well as zeolite and graphene oxide pervaporation membranes. In ZIF-8, -93, -95, and -97 with similar aperture size, water flux is governed by framework hydrophobicity/hydrophilicity; in hydrophobic ZIF-8 and -95, water flux is higher than in hydrophilic ZIF-93 and -97. Furthermore, water molecules in ZIF-93 move slowly and remain in the membrane for a long time but undergo to-and-fro motion in ZIF-100. The lifetime of hydrogen bonds in ZIF-93 is found to be longer than in ZIF-100. This simulation study quantitatively elucidates the dynamic and structural properties of water in ZIF membranes, identifies the key governing factors (aperture size and framework hydrophobicity/hydrophilicity), and suggests that ZIF-100 is an intriguing membrane for seawater pervaporation.