Silica Nanohybrid Membranes with High CO2 Affinity for Green Hydrogen Purification

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 significantl...

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Bibliographic Details
Published in:Advanced energy materials 2011-07, Vol.1 (4), p.634-642
Main Authors: Lau, Cher Hon, Liu, Songlin, Paul, Donald R., Xia, Jianzhong, Jean, Yan-Ching, Chen, Hongmin, Shao, Lu, Chung, Tai-Shung
Format: Article
Language:English
Subjects:
gas separation
hydrogen purification
membrane materials
silica nanocomposites
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Summary: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. Organic‐inorganic materials synthesized from sol‐gel chemistry yield well‐dispersed inorganic nanoclusters. Using a simple, acid‐catalyzed process, high CO2 affinity gas separation membranes are fabricated from polyether diamines and alkoxysilanes. The CO2 permeability of these membranes can reach 1950 Barrer while CO2/H2 and CO2/N2 selectivities are 11 and 56, respectively. Such membranes can potentially replace current high carbon footprint techniques while achieving high CO2/light gas separation factors in a sustainable manner.
ISSN:1614-6832
1614-6840
DOI:10.1002/aenm.201100195