CO2 removal by membrane processes is considerably potential for several applications
such as natural gas and synthesis gas purification, enhanced oil recovery application,
and carbon dioxide capture in combat against global warming. Dense polymeric
membranes are commonly utilized for these type of gas separation applications. Nevertheless,
the intrinsic properties of dense polymeric membranes, which commonly
characterize by the low gas permeability versus high gas selectivity trade–off or vice
versa, is less desirable. In order to meet the increased demand of CO2 removal,
a strategy to improve the gas separation performance of a polymeric membrane is
investigated in this study. With this regard, mixed matrix membranes in which inorganic
non porous fillers are incorporated into a polymeric matrix were prepared to
achieve the aforementioned objective. The mixed matrix membranes were prepared
from Pebax® block copolymers and PEG POSS® molecules. These hybrid membranes
were formed as both dense and multilayer composite membranes. The dense
transparent membranes with well–dispersed fillers could be obtained by variation of
the solvent mixture. The DSC analyses showed that incorporation of PEG POSS®
into Pebax® matrix altered the thermal properties of the matrix. The multilayer composite
membranes were then prepared from a PTMSP gutter layer deposited on a
PAN porous support and an adjacent hybrid Pebax®/PEG POSS® as the top layer.
These hybrid multilayer composite membranes exhibited an enhanced CO2 selectiv4
ity by a factor of two relative to the pure Pebax®. In these hybrid systems, the CO2
separation was presumably enhanced by the high ether oxides content from PEG
POSS® that has high affinities for CO2. For particular composition of Pebax® and
PEG POSS® concentrations, the PTMSP gutter layer harnessed the CO2 selectivity
without losing the CO2 permeation rate. At the same time, these membrane, however,
suffered severe adhesion between the gutter layer and the top selective layer, and
this problem led to the decreased separation performance. This study showed that
the hybrid multilayer composite membrane could be considerably attractive for CO2
removal application if the characteristics of each layer were appropriately matched
and optimized.
| Date of Award | May 10 2011 |
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| Original language | English (US) |
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| Awarding Institution | - Physical Sciences and Engineering
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| Supervisor | Klaus-Victor Peinemann (Supervisor) |
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