Title: Creation of Well-Defined “Mid-Sized” Micropores in Carbon Molecular Sieve Membranes

Abstract

Carbon molecular sieve (CMS) membranes are choices for the separation of organic molecules due to their stability, ability to be scaled at practical form factors, and the avoidance of expensive supports or complex multi-step fabrication processes. A critical challenge is the creation of “mid-range” (e.g., 5–9 Å) microstructures that allow for facile permeation of organic solvents and selection between similarly-sized guest molecules. In this work, we create these microstructures via the pyrolysis of a microporous polymer (PIM-1) under low concentrations of hydrogen gas. The introduction of H₂ inhibits aromatization of the decomposing polymer and ultimately results in the creation of a well-defined bimodal pore network that exhibits an ultramicropore size of 5.1 Å. The H₂ assisted CMS dense membranes show a dramatic increase in p-xylene ideal permeability (≈15 times), with little loss in p-xylene/o-xylene selectivity (18.8 vs. 25.0) when compared to PIM-1 membranes pyrolyzed under a pure argon atmosphere. This method is successfully extended to hollow fiber membranes operating in organic solvent reverse osmosis mode, highlighting the potential of this approach to be translated from the laboratory to the field.

Authors:

Ma, Yao  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8283-8645"

Jue, Melinda L.  ^[1];

• Search DOE PAGES for author "Jue, Melinda L."
• Search DOE PAGES for ORCID "0000-0002-6864-2419"

Zhang, Fengyi  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-2398-8176"

Mathias, Ronita  ^[1];

• Search DOE PAGES for author "Mathias, Ronita"
• Search DOE PAGES for ORCID "0000-0001-6858-8128"

Jang, Hye Youn  ^[1];

• Search DOE PAGES for author "Jang, Hye Youn"
• Search DOE PAGES for ORCID "0000-0002-0837-2058"

Lively, Ryan P.  ^[1]

• Search DOE PAGES for author "Lively, Ryan P."
• Search DOE PAGES for ORCID "0000-0002-8039-4008"

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+ Show Author Affiliations

1. Georgia Inst. of Technology, Atlanta, GA (United States)

Publication Date:

Sat Jun 22 00:00:00 EDT 2019

Research Org.:

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); ExxonMobil Research and Engineering

OSTI Identifier:

1566018

Report Number(s):

LLNL-JRNL-769201
Journal ID: ISSN 1433-7851; 960479

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Angewandte Chemie (International Edition)

Additional Journal Information:

Journal Name: Angewandte Chemie (International Edition); Journal Volume: 58; Journal Issue: 38; Journal ID: ISSN 1433-7851

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; carbon molecular sieves; hydrogen; membranes; polymers of intrinsic microporosity; xylene isomer separation