• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.12-12
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• 2004

A brief introduction was given in this paper for the research and development on membrane science and technology in China. Ion exchange membranes and electrodialysis, MF, UF, NF and RO membranes, gas separation (GS) membranes, pervaporation (PV), membranes, inorganic membranes (IM) and membrane reactors (MR) were involved.(omitted)

• Membrane Journal
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• v.30 no.6
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• pp.385-394
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• 2020

In the gas separation process, the separation membranes have to not only show high gas transport and selectivity but also exhibit exceptional stability at high temperature and pressure. However, when the polymeric membranes (particularly, glassy polymers) are exposed to the condensable gases (i.e., CO2, H2S, hydrocarbon, etc.), the polymer chains are prone to swell, leading to low stability. As a result, the plasticization behavior reduces the gas selectivity in the separation of mixture gases at high pressures and thus results in limited applications to the separation processes. To address these issues, many strategies have been studied such as thermal treatment, polymer blending, thermally rearrangement, mixed-matrix membranes, cross-linking, etc. In this review, we will understand the plasticization behavior and suggest potential methods based on the previously reported studies.

• Carbon letters
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• v.16 no.3
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• pp.183-191
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• 2015

Gas transport through graphene-derived membranes has gained much interest recently due to its promising potential in filtration and separation applications. In this work, we explore Kr-85 gas radionuclide sequestration from natural air in nanoporous graphene oxide membranes in which different sizes and geometries of pores were modeled on the graphene oxide sheet. This was done using atomistic simulations considering mean-squared displacement, diffusion coefficient, number of crossed species of gases through nanoporous graphene oxide, and flow through interlayer galleries. The results showed that the gas features have the densest adsorbed zone in nanoporous graphene oxide, compared with a graphene membrane, and that graphene oxide was more favorable than graphene for Kr separation. The aim of this paper is to show that for the well-defined pore size called P-7, it is possible to separate Kr-85 from a gas mixture containing Kr-85, O₂ and N₂. The results would benefit the oil industry among others.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.263-269
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• 1999

For effective $CO_2$ separation using pore size controlled membrane, silica was deposited in the mesopores of a $\gamma$-alumina film by chemical vapor deposition of tetraethoxysilane (TEOS) and phenyl-substituted ethoxysilanes at 773-873K. The membranes prepared with phenyl-substituted ethoxysilanes were calcined to remove the phenyl group and control the pore size. The gas permaselectivity of prepared membranes was evaluated by using $H_2$, $CO_2$ $N_2$, $CH_2$ and $C_3H_8$ single component and a mixture of $CO_2$ and $N_2$. The membranes produced using TEOS contained micropores having permselectivity only to hydrogen, but the phenyl-subsitituted ethoxysilane derived membranes possessed micorpores which are recognizable molecules of $CO_2$, $N_2$ and $CH_4$. In the diphenyl-diethoxysilane-derived membrane, the $CO_2$ permeance and selectivity of $CO_2$/$CH_4$ were $10^{-6} m^3(STP) \cdot m^{-2} \cdot s^{-1} \cdot kPa^{-1}$ and 11, respectively. Therefore, the use of phenyl-substituted ethoxysilane was effective in controlling micropore size for $CO_2$ separation.

• Membrane Journal
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• v.22 no.2
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• pp.142-154
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• 2012

In order to remove $CO_2$ from the DME plant process, we investigated the composite membrane with rubbery polymers as the separation layer and its separation performance of $CO_2$ and $H_2$. Hollow fiber membranes for supporting layer were prepared by solution spinning method. In case of using PDMS as a separation layer, the composite membranes showed the permeation rates of $CO_2$ were over 300 GPU and minimum $CO_2/H_2$ selectivitties were 4.3 and in case of using PEBAX as a separation layer, the composite membranes showed the permeation rates of $CO_2$ were over 120 GPU and minimum $CO_2/H_2$ selectivities were 5.

• Membrane Journal
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• v.14 no.2
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• pp.99-107
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• 2004

Carbon molecular sieve (CMS) membranes were prepared by pyrolysis of polyimides having carboxylic acid groups and applied to the hydrogen separation. The polymeric membranes having carboxylic acid groups showed different steric properties as compared with polymeric membranes having other side groups ($-CH_3$ and $-CF_3$) because of the hydrogen bond between the carboxylic acid groups. However, the microporous CMS membranes were significantly affected by the decomposable side groups evidenced from the wide angle X-rat diffraction, nitrogen adsorption isotherms, and single gas permeation measurement. Furthermore, the gas separation properties of the CMS membranes were essentially affected by the pyrolysis temperature. As a result, the CMS membranes Prepared by Pyrolysis of polyimide containing carboxylic acid froups at $700^{\circ}C$ showed the $H_2$ permeability of 3,809 Baller [$1{\times}10^{-10}$ H $\textrm{cm}^$(STP)cm/$\textrm{cm}^2$.s.cmHg], $H_2$/$N_2$, selectivity of 46 and $H_2$/$CH_4$ selectivity of 130 while the CMS membranes derived from polyimide showed the H$_2$ permeability of 3,272 Barrer, $H_2$/$N_2$ selectivity of 136 and $H_2$/$CH_4$ selectivity of 177.

• Korean Membrane Journal
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• v.3 no.1
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• pp.51-58
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• 2001

The surface of Poly(ether imide) (PEI) membranes has been sulfonated using CIS03H. The resulting membranes were characterized through the analysis of ESCA and contact angle measurements The sulfonated PEI membranes were exposed to gases of $O_2$, $N_2$, and $CO_2$ to measure the permeation rates and ideal separation factors. In addition, the diffusivities and solubilities of individual gases were measured. The diffusivity effect is more dominant than the solubility one on gas transports.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.47-50
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• 2003

Carbon-silica membranes were Prepared by Pyrolyzing polyimide/silica composite obtained from ill-situ polymerization of alkoxy silanes via sol-gel reaction. In this study, effects of silica content and silica network in polyimide matrix were focused on the gas permeation and separation properties of the final carbon-silica membrane. The membranes prepared were characterized with a field emission scanning electron microscopy (FE-SEM), a solid state $^{29}$ Si nuclear magnetic resonance spectroscopy ($^{29}$ Si-NMR), an electron spectroscopy for chemical analysis (ESCA), a thermogravimetric analysis (TGA) and gas permeation tests.

• Korean Membrane Journal
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• v.2 no.1
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• pp.48-55
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• 2000

In order to improve organic vapor separation efficiency of polydimethylsiloxane (PDMS) membrane, various zeolites (zeolite 4A, zeolite 13X and natural zeolite) were introduced into a thin PDMS film. The measurements of permeability and selectivity of zeolite-filled PDMS membranes were carried out with a CO$_2$gas and a CO$_2$gas/acetic acid vapor mixture, respectively. The CO$_2$permeability of zeolite-filled membranes decreased with increasing zeolite content and then recovered up to 30 wt% content. The effect of zeolite type on the improvement of CO$_2$permeability was found to be in the order of zeolite 13X > natural zeolite > 4A. The CO$_2$selectivity of zeolite-filled membranes was enhanced up to 9 times compared with the selectivity of a pure (unfilled) PDMS membrane. The effect of zeolite type on the improvement of CO$_2$selectivity was found to be in the order of natural zeolite > zeolite 13X > zeolite 4A.

• Korean Membrane Journal
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• v.6 no.1
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• pp.16-23
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• 2004

The silica containing carbon (C-SiO$_2$) membranes were fabricated using poly(imide siloxane) (PIS) having -CO- swivel group. The characteristics of porous C-SiO$_2$ structures prepared by the pyrolysis of poly(imide siloxane) were related with the micro-phase separation between the imide block and the siloxane block. Furthermore, the nitrogen adsorption isotherms of the CMS and the C-SiO$_2$ membranes were investigated to define the characteristics of porous structures. The C-SiO$_2$ membranes derived from PIS showed the type IV isotherm and possessed the hysteresis loop, which was associated with the mesoporous carbon structures, while the CMS membranes derived from PI showed the type I isotherm. For the molecular sieving probe, the C-SiO$_2$ membranes pyrolyzed at 550, 600, and 700$^{\circ}C$ showed the O$_2$ permeability of 924, 1076, and 367 Barrer (1 ${\times}$ 10$\^$-10/㎤(STP)cm/$\textrm{cm}^2$$.$s$.$cmHg) and O$_2$/N$_2$ selectivity of 9, 8, and 12.