title: Reverse-selective microporous membrane for gas separation.
abstract: Reverse-selective membranes, through which bigger molecules selectively permeate, are attractive for developing chemical processes utilizing hydrogen because they can maintain the high partial pressure of hydrogen required for their further downstream utilization. Although several of these chemical processes are operated above 473 K, membranes with outstanding reverse-selective separation performance at these temperatures are still to be reported. Herein, we propose a new adsorption-based reverse-selective membrane that utilizes a Na cation occluded in a zeolitic framework. The membrane developed in this work, a compact Na(+)-exchanged ZSM-5 (NaZSM-5) type zeolite membrane, enables us to selectively permeate and separate bigger polar molecules, such as methanol and water, from a stream containing hydrogen, above 473 K. On the other hand, a Na(+)-free, H(+)-exchanged ZSM-5 (HZSM-5) type zeolite membrane did not show separation properties at these temperatures. The microporous zeolite membrane developed in this study can be applied to a variety of chemical reaction systems to minimize energy consumption.
authors.affiliation: Department of Applied Chemistry, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Sawamura
authors.forename: Teruaki
authors.initials: T
authors.lastname: Izumi
authors.forename: Kiyotoshi
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Shintaro
authors.initials: S
authors.lastname: Daikohara
authors.forename: Tetsu
authors.initials: T
authors.lastname: Ohsuna
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Takada
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sekine
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kikuchi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Matsukata