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Title: Linking CO 2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering

Abstract

Composites of poly(ethylenimine) (PEI) and mesoporous silica are effective, reversible adsorbents for CO 2, both from flue gas and in direct air-capture applications. The morphology of the PEI within the silica can strongly impact the overall carbon capture efficiency and rate of saturation. Here, we directly probe the spatial distribution of the supported polymer through small-angle neutron scattering (SANS). Combined with textural characterization from physisorption analysis, the data indicate that PEI first forms a thin conformal coating on the pore walls, but all additional polymer aggregates into plug(s) that grow along the pore axis. This model is consistent with observed trends in amine-efficiency (CO 2/N binding ratio) and pore size distributions, and points to a trade-off between achieving high chemical accessibility of the amine binding sites, which are inaccessible when they strongly interact with the silica, and high accessibility for mass transport, which can be hampered by diffusion through PEI plugs. In conclusion, we illustrate this design principle by demonstrating higher CO 2 capacity and uptake rate for PEI supported in a hydrophobically modified silica, which exhibits repulsive interactions with the PEI, freeing up binding sites.

Authors:
 [1];  [1];  [1]
  1. School of Chemical &, Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Georgia 30332, United States
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC), Washington, D.C. (United States). Center for Understanding and Control of Acid Gas-induced Evolution of Materials for Energy (UNCAGE-ME)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1213924
Alternate Identifier(s):
OSTI ID: 1386055
Grant/Contract Number:  
SC0012577
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Name: Journal of the American Chemical Society Journal Volume: 137 Journal Issue: 36; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); defects; membrane; carbon capture; materials and chemistry by design; synthesis (novel materials); synthesis (self-assembly); synthesis (scalable processing)

Citation Formats

Holewinski, Adam, Sakwa-Novak, Miles A., and Jones, Christopher W. Linking CO 2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering. United States: N. p., 2015. Web. doi:10.1021/jacs.5b06823.
Holewinski, Adam, Sakwa-Novak, Miles A., & Jones, Christopher W. Linking CO 2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering. United States. https://doi.org/10.1021/jacs.5b06823
Holewinski, Adam, Sakwa-Novak, Miles A., and Jones, Christopher W. Wed . "Linking CO 2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering". United States. https://doi.org/10.1021/jacs.5b06823.
@article{osti_1213924,
title = {Linking CO 2 Sorption Performance to Polymer Morphology in Aminopolymer/Silica Composites through Neutron Scattering},
author = {Holewinski, Adam and Sakwa-Novak, Miles A. and Jones, Christopher W.},
abstractNote = {Composites of poly(ethylenimine) (PEI) and mesoporous silica are effective, reversible adsorbents for CO2, both from flue gas and in direct air-capture applications. The morphology of the PEI within the silica can strongly impact the overall carbon capture efficiency and rate of saturation. Here, we directly probe the spatial distribution of the supported polymer through small-angle neutron scattering (SANS). Combined with textural characterization from physisorption analysis, the data indicate that PEI first forms a thin conformal coating on the pore walls, but all additional polymer aggregates into plug(s) that grow along the pore axis. This model is consistent with observed trends in amine-efficiency (CO2/N binding ratio) and pore size distributions, and points to a trade-off between achieving high chemical accessibility of the amine binding sites, which are inaccessible when they strongly interact with the silica, and high accessibility for mass transport, which can be hampered by diffusion through PEI plugs. In conclusion, we illustrate this design principle by demonstrating higher CO2 capacity and uptake rate for PEI supported in a hydrophobically modified silica, which exhibits repulsive interactions with the PEI, freeing up binding sites.},
doi = {10.1021/jacs.5b06823},
url = {https://www.osti.gov/biblio/1213924}, journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 36,
volume = 137,
place = {United States},
year = {2015},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at https://doi.org/10.1021/jacs.5b06823

Citation Metrics:
Cited by: 18 works
Citation information provided by
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Works referencing / citing this record:

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Observation of the wrapping mechanism in amine carbon dioxide molecular interactions on heterogeneous sorbents
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Stability of amine-functionalized CO 2 adsorbents: a multifaceted puzzle
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Molecular blends of methylated-poly(ethylenimine) and amorphous porous organic cages for SO 2 adsorption
journal, January 2018