An Extrinsic‐Pore‐Containing Molecular Sieve Film: A Robust, High‐Throughput Membrane Filter. Issue 3 (19th November 2020)

• Record Type: Journal Article
• Authors: Hong, Sungwon; Jeong, Yanghwan; Baik, Hionsuck; Choi, Nakwon; Yip, Alex C. K.; Choi, Jungkyu
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 3(2021)
• Page Start: 1323
• Page End: 1331
• Publication Date: 2020-11-19
• Subjects: defect-free membranes -- hierarchical porous structure -- MFI type zeolite membranes -- non-zeolitic-pore-containing film -- p-/o-xylene separations; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202010957
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: MFI type zeolites with 10‐membered‐ring pores (ca. 0.55 nm) have the ability to separate p‐xylene (ca. 0.58 nm) from its bulkier isomers. Here, we introduced non‐zeolitic micropores (ca. 0.6–1.5 nm) and mesopores (ca. 2–7 nm) to a conventional microporous MFI type zeolite membrane, yielding an unprecedented hierarchical membrane structure. The uniform, embedded non‐zeolitic pores decreased defect formation considerably and facilitated molecular transport, resulting in high p‐xylene perm‐selectivity and molar flux. Specifically, compared to a conventional, crack network‐containing MFI membranes of similar thickness (ca. 1 μm), the mesoporous MFI membranes showed almost double p‐xylene permeance (ca. 1.6±0.4×10 −7 mol m −2 s −1 Pa −1 ) and a high p‐/o‐xylene separation factor (ca. 53.8±7.3 vs. 3.5±0.5 in the conventional MFI membrane) at 225 °C. The embedded non‐zeolitic pores allowed for decreasing the separation performance degradation, which was apparently related to coke formation. Abstract : Non‐zeolitic‐pores were successfully embedded inside a microporous MFI type zeolite membrane. The resulting hierarchical structure was beneficial for achieving robust, high p ‐xylene separation performance.