• Membrane Journal
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• v.25 no.2
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• pp.107-114
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• 2015

PTMSP-NaA zeolite composite membranes were prepared by adding 0~50 wt% NaA zeolite to PTMSP. The membranes were characterized by FT-IR, $^1H$-NMR, GPC, DSC, TGA, SEM. The permeabilities of $H_2$ and $N_2$ gases through PTMSP-NaA zeolite composite membranes was studied as a function of NaA zeolite contents. According to TGA measurements, when zeolite was inserted into the polymer, weight loss temperature and weight loss wt% of PTMSP-NaA zeolite composite membranes were decreased. Based on SEM observation, NaA zeolite was dispersed in the PTMSP-NaA zeolite composite membrane with the size $2{\sim}5{\mu}m$. The permeability of PTMSP-NaA zeolite composite membranes increased added as NaA zeolite content increased. On the contrary, the selectivity ($H_2/N_2$) of the composite membranes decreased as NaA zeolite content increased. PTMSP-NaA zeolite composite membrane showed better permeability and selectivity ($H_2/N_2$) of $H_2$ and $N_2$ than PTMSP-NaY zeolite composite membrane.

• 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.

• Membrane Journal
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• v.22 no.5
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• pp.342-351
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• 2012

In this study, PTMSP[poly(1-trimethylsilyl-1-propyne)]/PDMS[poly(dimethylsioxane)]-NaY zeolite and PTMSP/PDMS-NaA zeolite composite membranes were made to incorporate zeolite into PTMSP/PDMS graft copolymer in order to improve the selectivity and thermal stability, the drop of permeability by physical aging effect during long period of time for the PTMSP membrane. To investigate the physico-chemical characteristics of composite membranes, the analytical methods such as FT-IR, $^1H$-NMR, TGA, SEM, and GPC have been utilized. The gas permeability and selectivity properties of $H_2$ and $N_2$ were evaluated. The permeability of the PTMSP/PDMS-NaY zeolite and PTMSP/PDMS-NaA zeolite composite membranes than PTMSP/PDMS graft copolymer membrane increased, increased as zeolite content increased. On the contrary, the selectivity ($H_2/N_2$) of the composite membranes decreased as zeolite content increased. PTMSP/PDMS-NaA zeolite composite membrane showed better permeability and separation factor than PTMSP/PDMS-NaY zeolite composite membrane.

• Membrane Journal
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• v.25 no.3
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• pp.295-300
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• 2015

PDMS-NaA zeolite membranes were prepared by adding 0~40 wt% NaA zeolite. Based on SEM observation, NaA zeolite was dispersed in the PDMS-NaA zeolite membranes with $2{\sim}5{\mu}m$. The permeabilities of $H_2$ and $N_2$ gases through PDMS-NaA zeolite membranes increased as NaA zeolite contents increased and $H_2$ gas had better permeabilities than $N_2$. The selectivity ($H_2/N_2$) of PDMS-NaA zeolite membranes increased as NaA zeolite contents increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.95-101
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• 2007

The synthesis of NaA zeolite membrane on a porous alumina support from clear solution by using hydrothermal reaction was investigated. Effects of reaction temperature, reaction time and seeding for transformation of zeolite A membrane and powder which are produced in the reactor were monitored through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The transformation process of producing Zeolite A membrane starts from the formation of the compact and continuous membrane on the surface of porous support from clear solution. The large Zeolite A poly-crystal was then farmed through the dissolution process. Finally, the process was advanced from sodalite to amorphous. In case of powder, sodalite is formed in the early stage of reaction because of surrounding space difference between membrane and powder crystal. Discrete surrounding space of powder crystal makes easy to transform to sodalite. From Zeolite A to amorphous through transformed product was rapidly advanced at high temperature while the membrane with somewhat low coverage was obtained at low temperature. A compact and continuous zeolite A membrane was synthesized at $120^{\circ}C$ in 12-hour period.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.61-67
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• 2005

Zeolite membranes show better thermal, mechanical, chemical stabilities than polymer membranes. Water was separated from water/ethanol mixtures by pervaporation using the NaA and the NaY zeolite membranes synthesized in our laboratory. The effects of concentration of ethanol at the feed side and temperature were studied on the permeation flux and separation factor of water. The separation factors obtained with the NaA zeolite membrane was found to be 1000 times higher than those obtained with the NaY. However, the water flux through the NaA zeolite membrane was observed to be lower than 1/2 of that through the NaY zeolite membrane.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.5-8
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• 1997

Introduction : Membranes made from inorganic materials are generally superior to organo-polymeric materials in thermal and mechanical stability, and chemical resistance. Among inorganic materials zeolite is a promising candidate for a high performance membrane because of the unique characteristics of zeolite crystals such as molecular sieving, ion exchange, selective adsorption and catalysis. Although there are many recent reportsl on the preparation of zeolitc membranes and the gas permeation through the membranes, only a limited number of publications deal with pervaporation studies. Recently, we have reported a high pervaporation performance of NaA zeolite membrane for the separation of water/organic liquid mixtures. and of NaY zeolite menlbrane for the separation of methanol/MTBE. Here, preparation of zeolite (LTA, ZSM-5 and FAU) membranes and their permeation properties are discussed.

• Korean Membrane Journal
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• v.8 no.1
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• pp.21-30
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• 2006

A faujasite NaY zeolite membrane was prepared on a tubular ${\alpha}-Al_2O_3$ support by the secondary growth process, and effects of permeation test conditions on the $CO_2/N_2$ separation were investigated. A NaY zeolite membrane with good $CO_2/N_2$ separation was successfully synthesized by using the hydrothermal solution ($Al_2O_3:SiO_2:Na_2O:H_2O$ = 1:6:14:840 in a molar base): at a permeation temperature of $30^{\circ}C$, its $CO_2$ permeance and $CO_2/N_2$ separation factor were $2.5{\times}10^{-7}mol/m^2secPa$ and 34, respectively. The $CO_2$ and $N_2$ permeations were highly dependent on permeation test conditions (feed composition, feeding rate, feed pressure, He sweeping rate and permeation temperature). The results indicated that (i) $CO_2$ and $N_2$ permeations through NaY zeolite membrane are governed by surface and micropore diffusions, respectively, (ii) the preparation of NaY zeolite membrane with a large permeating area is one of the most difficult hurdles for its real applications, and (iii) the retardation of $N_2$ permeation is an effective key to improve $CO_2/N_2$ separation factor in NaY zeolite membrane.

• Membrane and Water Treatment
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• v.8 no.5
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• pp.437-448
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• 2017

A high quality Na-X zeolite membrane was synthesized on a seeded ${\alpha}-alumina$ disc by the secondary growth method. Structural characterization was done by X-ray spectroscopy, FT-IR spectroscopy, SEM and AFM imaging. The performance evaluation of the membrane was firstly tested in separation of glucose/water solutions by pervaporation process. There was obtained a separation factor $182.7{\pm}8.8$, while the flux through the membrane was $3.6{\pm}0.3kg\;m^{-2}\;h^{-1}$. The zeolite membrane was then used for desalination of aqueous solutions consisting of $Na^+$, $Ca^{2+}$, $Cs^+$ and $Sr^{2+}$ because of the importance of these ions in water and wastewater treatments. The effects of some parameters such as temperature and solution concentration on the desalination process were studied for investigating of diffusion/adsorption mechanism in membrane separation. Finally, high water fluxes ranged from 2 up to $9kg\;m^{-2}\;h^{-1}$ were obtained and the rejection factors were resulted more than 95% for $Na^+$ and $Ca^{2+}$ and near to 99% for $Cs^+$ and $Sr^{2+}$. Based on the results, fluxes were significantly improved due to convenient passage of water molecules from large pores of NaX, while the fouling was declining dramatically. Based on the results, NaX zeolite can efficiently use for the removal of different cations from wastewaters.

• Korean Membrane Journal
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• v.8 no.1
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• pp.31-35
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• 2006

Pervaporation of water/2,2,2-trifluoroethanol (TFEA) mixtures was performed using a NaY zeolite membrane which was prepared by a hydrothermal synthesis. Pervaporation with a zeolite membrane is one of the economic separation technologies for liquid mixtures including organic/water solutions. The effects of a TFEA feed concentration and a temperature were studied on the permeation flux and the separation factor. Not only the water flux increased significantly with the increase of the operating temperature, but also the TFEA flux through the NaY zeolite membrane rapidly increased with the increase of the temperature at the feed concentration below 0.8 mole fraction of TFEA.