Constructing superhydrophobic ZIF -8 layer with bud -like surface morphology on PDMS composite membrane for highly efficient ethanol/ water separation
Constructing superhydrophobic ZIF -8 layer with bud -like surface morphology on PDMS composite membrane for highly efficient ethanol/ water separation
复制标题
在PDMS复合膜上构建具有芽状表面形态的超疏水ZIF -8层用于高效乙醇/水分离
DOI：
10.1016/j.jece.2020.104977
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发表时间：
2021
影响因子：
7.7
通讯作者：
Wang Yan
中科院分区：
文献类型：
--
作者：
Pan Yong;Zhu Tengyang;Xia Qing;Yu Xi;Wang Yan
新兴的渗透汽化技术有望实现从生物质发酵液中回收清洁可再生的生物乙醇。这项技术的巨大挑战是需要一种具有高分离性能的渗透汽化膜。基于溶液扩散机理，乙醇回收渗透汽化膜应具有疏水选择性层，以提高对乙醇分子的吸附能力，从而提高分离性能。本研究在聚二甲基硅氧烷(PDMS)复合膜上制备了具有纳米级芽状表面形貌的超疏水分子筛咪唑骨架-8(ZIF-8)膜，通过ZIF-8颗粒浸渍、二次晶种生长和正十八烷基膦酸疏水修饰，实现了乙醇/水的高效分离。系统研究了ZIF-8二次生长过程中2-甲基咪唑与硝酸锌的摩尔比(Hmim/Zn2+)，以期在PDMS复合膜上构建合适的微纳米结构。制得的最佳复合膜的水接触角为163°，乙醇接触角为0°。此外，在30℃℃下，5%乙醇水溶液的分离系数为17.4，相当于总通量为0.64g/m2h.因此，其渗透汽化性能优于大多数已报道的聚二甲基硅氧烷混合基质膜.在聚二甲基硅氧烷(PDMS)复合膜上构建超疏水层的策略可能为制备高性能的渗透汽化膜以回收水溶液中的有机物质提供有意义的指导。
Emerging pervaporation technology is very promising to realize clean and renewable bioethanol recovery from biomass fermentation broth. The huge challenge of this technology is the need for a pervaporation membrane with high separation performance. Based on the solution-diffusion mechanism, pervaporation membrane for ethanol recovery should possess hydrophobic selective layer to improve sorption ability toward ethanol molecules, thereby enhancing the separation performance. In this study, a superhydrophobic zeolitic imidazolate framework-8 (ZIF-8) layer with a nano-level bud-like surface morphology was grown on polydimethylsiloxane (PDMS) composite membrane via ZIF-8 particle dip-casting, secondary seeded growth, and hydrophobic modification by n-octadecylphosphonic acid for highly efficient ethanol/water separation. The mole ratio of 2-methylimidazole and zinc nitrate (Hmim/Zn2+) in the process of ZIF-8 secondary growth was systematically studied to construct appropriate micro-nano structure on PDMS composite membrane. The resultant optimal composite membrane exhibited a water contact angle of about 163° and an ethanol contact angle of 0°. In addition, it also displayed an outstanding separation factor of 17.4 corresponding to a total flux of 0.64 kg/m2h with 5 wt% ethanol aqueous solution at 30 ℃, and thus the superior pervaporation performance to most other reported PDMS-based mixed matrix membranes. The strategy of constructing superhydrophobic layer on PDMS composite membrane may provide a meaningful guidance for preparing high-performance pervaporation membrane for organic recovery from aqueous solution.