Abstract It is highly desirable to prepare defect-free ZIF-8 membranes on commercially attractive scalable polymer hollow fibers, especially on the bore side of the fibers, yet quite challenging. Herein, we report a facile synthesis of well-intergrown ZIF-8 membranes on polyvinylidene fluoride (PVDF) microfiltration hollow fibers by a secondary growth method. Surface modification using a strong base promoted high heterogeneous nucleation, resulting in densely packed ZIF-8 seed layers on the hollow fibers. The seed crystals were secondarily grown under a continuous flow of growth solution to form ZIF-8 membranes with thickness of ˜1.2 μm. The prepared ZIF-8 membranes achieved high gas permeances, reaching values of 16,344 × 10−10 mol m-2 s-1 Pa-1 for H2 and 197 × 10−10 mol m-2 s-1 Pa-1 for C3H6. The selectivities for H2/CH4, H2/C3H6, H2/C3H8 and C3H6/C3H8 gas pairs were found to be 12, 57, 160 and 15, respectively. We anticipate that the method could potentially be applied to transform commercial PVDF ultrafiltration/microfiltration hollow fibers commonly used for water separation into high quality ZIF-8 membranes for H2 purification and C3H6/C3H8 separation.

中文翻译：

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用于回收氢气和丙烯的聚偏二氟乙烯中空纤维上多晶 ZIF-8 膜的流动合成

摘要 非常需要在具有商业吸引力的可缩放聚合物中空纤维上制备无缺陷的 ZIF-8 膜，尤其是在纤维的孔侧，但非常具有挑战性。在此，我们报告了通过二次生长方法在聚偏二氟乙烯 (PVDF) 微滤中空纤维上轻松合成良好共生的 ZIF-8 膜。使用强碱进行表面改性促进了高异质成核，从而在中空纤维上形成了密集的 ZIF-8 种子层。晶种在连续的生长溶液流下二次生长以形成厚度为～1.2μm的ZIF-8膜。制备的 ZIF-8 膜实现了高气体渗透率，H2 达到 16,344 × 10-10 mol m-2 s-1 Pa-1，C3H6 达到 197 × 10-10 mol m-2 s-1 Pa-1。H2/CH4、H2/C3H6、发现 H2/C3H8 和 C3H6/C3H8 气体对分别为 12、57、160 和 15。我们预计该方法有可能用于将通常用于水分离的商用 PVDF 超滤/微滤中空纤维转化为用于 H2 纯化和 C3H6/C3H8 分离的高质量 ZIF-8 膜。