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An Extrinsic‐Pore‐Containing Molecular Sieve Film: A Robust, High‐Throughput Membrane Filter
Author(s) -
Hong Sungwon,
Jeong Yanghwan,
Baik Hionsuck,
Choi Nakwon,
Yip Alex C. K.,
Choi Jungkyu
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202010957
Subject(s) - permeance , molecular sieve , microporous material , mesoporous material , membrane , zeolite , chemical engineering , selectivity , zsm 5 , materials science , xylene , chemistry , adsorption , organic chemistry , catalysis , toluene , biochemistry , engineering
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.