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Title: Ultraselective Carbon Molecular Sieve Membranes with Tailored Synergistic Sorption Selective Properties

 [1];  [1]
  1. School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive Atlanta GA 30332 USA
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Journal Article: Publisher's Accepted Manuscript
Journal Name:
Advanced Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 33; Related Information: CHORUS Timestamp: 2017-09-01 21:55:55; Journal ID: ISSN 0935-9648
Wiley Blackwell (John Wiley & Sons)
Country of Publication:

Citation Formats

Zhang, Chen, and Koros, William J. Ultraselective Carbon Molecular Sieve Membranes with Tailored Synergistic Sorption Selective Properties. Germany: N. p., 2017. Web. doi:10.1002/adma.201701631.
Zhang, Chen, & Koros, William J. Ultraselective Carbon Molecular Sieve Membranes with Tailored Synergistic Sorption Selective Properties. Germany. doi:10.1002/adma.201701631.
Zhang, Chen, and Koros, William J. Mon . "Ultraselective Carbon Molecular Sieve Membranes with Tailored Synergistic Sorption Selective Properties". Germany. doi:10.1002/adma.201701631.
title = {Ultraselective Carbon Molecular Sieve Membranes with Tailored Synergistic Sorption Selective Properties},
author = {Zhang, Chen and Koros, William J.},
abstractNote = {},
doi = {10.1002/adma.201701631},
journal = {Advanced Materials},
number = 33,
volume = 29,
place = {Germany},
year = {Mon Jul 03 00:00:00 EDT 2017},
month = {Mon Jul 03 00:00:00 EDT 2017}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on July 3, 2018
Publisher's Accepted Manuscript

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Cited by: 1work
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  • Pressure swing adsorption techniques with the use of carbon molecular sieves (CMS) are now all established for the separation of individual components of gas mixtures. One important example of such a separation is the isolation of pure oxygen and nitrogen from air. Recently K.M. Thomas, M.L. Sykes and H. Chagger have shown that the heat evolution which accompanies the adsorption of O{sub 2} and N{sub 2} on various CMS`s from a stream of helium, takes place at rates which are closely similar to the heats of adsorption, with nitrogen adsorbing much more slowly than oxygen. The work was carried outmore » at room temperature and at atmospheric pressures. Pressure swing separation processes which are used industrially, employ adsorption pressures that can vary from atmospheric pressure to 20 barg. The application of pressure increases the adsorption of individual components of gas mixtures and generates heat evolution due not only to adsorption of the first layer of molecules, but also to the pore filling phenomena which density the gas contained in micropores. The heats evolved or absorbed during pressure swing operations are important parameters which affect the efficiency of gas separation operations as indicated recently by Sircar. But so far experimental determination of the heats of pore filling and gas adsorption on molecular sieves have not received much attention. This work was carried out, to determine experimentally the effect of pressure on heat evolution during adsorption of O{sub 2} and N{sub 2} on a commercial molecular sieve and an active carbon using a Microscal Flow Microcalorimeter (FMC) modified for use at high pressures under static conditions. The pressures of oxygen and nitrogen in contact with the adsorbent were increased in steps from 1 to 20 barg and decreased back to atmospheric pressures and the resulting heats of sorption determined together with the duration of each heat effect. A limited amount of work was also carried out on nitric oxide.« less
  • A new class of carbon molecular sieve membranes (CMSMs) has been prepared by carbonization of polyetherimide-coated mesoporous tubular supports. The membranes show higher permeance and better separation factors than other supported CMSMs reported in the literature for the CO{sub 2}/CH{sub 4} and H{sub 2}/CH{sub 4} binary mixtures as well as for the CO{sub 2}H{sub 2}/CH{sub 4} ternary mixture. CO{sub 2}/CH{sub 4} separation factors as high as 145 for the equimolar binary and 155 for the ternary mixture were obtained with a CO{sub 2} permeance about 0.15 (cm{sup 3}/cm{sup 2}{center_dot}psi{center_dot}min). The corresponding H{sub 2}/CH{sub 4} separation factors for the equimolar binarymore » and ternary mixtures were 68 and 50, respectively, with a H{sub 2} permeance of 0.13 (cm{sup 3}/cm{sup 2}{center_dot}psi{center_dot}min). The membrane also shows good stability when tested with CO{sub 2} and Ar single gases, as well as with an equimolar mixture of CO{sub 2}/CH{sub 4}. To study the mechanism of permeation and separation in CMSMs, tests with single gases as well as with binary and ternary mixtures were performed at different temperatures, transmembrane pressure differences, and feed compositions. Elemental analysis, scanning electron microscopy, and gas adsorption were also employed to study the morphology of the resulting membranes. Elemental analysis shows that although the structure consists mostly of carbon, it also still contains oxygen, nitrogen and hydrogen. Scanning electron microscopy of the cross section of the carbonized membrane shows that the carbonized layer lies essentially within the mesoporous {gamma}-alumina layer, a result also verified by N{sub 2} adsorption analysis at 77 K. The experimental data were compared with simulation results with the same mixtures using a nonequilibrium molecular dynamics method.« less
  • Thin carbon molecular sieve membranes (<500 nm) were fabricated inside of long geometry (9 inch) of stainless steel tubes with all welded construction. Alumina intermediate layer on porous stainless steel tube support was used to reduce effective support pore size and to provide a more uniform surface roughness. Novolac phenolic resin solution was then coated on the inside of porous stainless steel tube by slip casting while their viscosities were controlled from 5 centipoises to 30 centipoises. Carbonization was carried out at 700 °C in which thermal stress was minimized and high quality carbon films were prepared. The highest separationmore » performance characteristics were obtained using 20 cP phenolic resin solutions. The fabricated CMSM showed good separation factor for He/N 2 462, CO 2/N 2 97, and O 2/N 2 15.4. As the viscosity of polymer precursor solution was reduced from 20 cP to 15 cP, gas permeance values almost doubled with somewhat lower separation factor He/N 2 156, CO 2/N 2 88, and O 2/N 2 7.7.« less