Silica Nanohybrid Membranes with High CO2 Affinity for Green Hydrogen Purification

Authors

  • Cher Hon Lau,

    1. Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
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  • Songlin Liu,

    1. Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
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  • Donald R. Paul,

    1. Department of Chemical Engineering, The University of Texas at Austin, 1 University Station C0400, Austin TX 7812-0231, USA
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  • Jianzhong Xia,

    1. Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
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  • Yan-Ching Jean,

    1. Department of Chemistry, University of Missouri—Kansas City, 5100 Rockhill Road, Kansas City, MO 64110, USA
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  • Hongmin Chen,

    1. Department of Chemistry, University of Missouri—Kansas City, 5100 Rockhill Road, Kansas City, MO 64110, USA
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  • Lu Shao,

    Corresponding author
    1. School of Chemical Engineering and Technology, State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 150001, PR China
    • School of Chemical Engineering and Technology, State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 150001, PR China.
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  • Tai-Shung Chung

    Corresponding author
    1. Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
    • Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117576 Singapore
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Abstract

An effective separation of CO2 from H2 can be achieved using currently known polyethylene oxide (PEO)-based membranes at low temperatures but the CO2 permeability is inadequate for commerical operations. For commercial-scale CO2/H2 separation, CO2 permeability of these membranes must be significantly enhanced without compromising CO2/H2 selectivity. We report here exceptional CO2/H2 separation properties of a nanohybrid membrane comprising polyethylene glycol methacrylate (PEGMA) grafts on an organic-inorganic membrane (OIM) consisting of a low molecular weight polypropylene oxide (PPO)-PEO-PPO diamine and 3-glycidyloxypropyltrimethoxysilane (GOTMS), an alkoxysilane. The CO2 gas permeability of this nanohybrid membrane can reach 1990 Barrer with a CO2/H2 selectivity of 11 at 35 °C for a mixed gas mixture comprising 50% CO2 - 50% H2 at 3.5 atm. The transformation of the inorganic silica phase from a well-dispersed network of finely defined nanoparticles to rough porous clusters appears to be responsible for this OIM membrane exceeding the performance of other state-of-the-art PEO-based membranes.

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