• Macromolecular Research
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• v.17 no.2
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• pp.104-109
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• 2009

Solid-state facilitated, olefin transport membranes were prepared by complexation of poly(styrene-b-iso-prene-b-styrene) (SIS) block copolymer and silver salt. Facilitated olefin transport was not observed up to a silver mole fraction of 0.14, representing a threshold concentration, above which transport increased almost linearly with increasing silver salt concentration. This was because firstly the silver ions were selectively coordinated with the C=C bonds of PI blocks up to a silver mole fraction of 0.20, and secondly the coordinative interaction of the silver ions with the aliphatic C=C bond was stronger than that with the aromatic C=C bond, as confirmed by FT-Raman spectroscopy. Small angle X-ray scattering (SAXS) analysis showed that the cylindrical morphology of the neat SIS block copolymer was changed to a disordered structure at low silver concentrations ($0.01{\sim}0.02$). However, at intermediate silver concentrations ($0.15{\sim}0.20$), disordered-ordered structural changes occurred and finally returned to a disordered structure again at higher silver concentrations (>0.33). These results demonstrated that the facilitated olefin transport of SIS/silver salt complex membrancs was significantly affected by their coordinative interactions and nano-structural morphology.

• Membrane Journal
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• v.31 no.3
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• pp.212-218
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• 2021

It is inevitable to generate incomplete combustion gases when mankind utilizes fossil fuels. From this point of view, gas separation process of combustion gas suggests the possibility of recycling CO gas. In this study, we fabricated a facilitated transport polymeric composite membrane for CO separation using AgBF₄ and HBF₄. The copolymer was synthesized via free-radical polymerization of poly(vinyl alcohol) (PVA) as a main chain and acrylic acid (AA) monomer as a side chain. The polymer synthesis was confirmed by FT-IR and the interactions of graft copolymer with AgBF₄, and HBF₄ were characterized by TEM. PVA-g-PAA graft copolymer membranes showed good channels for facilitated CO transport. In this perspective, we suggest the novel approach in CO separation membrane area via combination of grafting and facilitated transport.

• Membrane Journal
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• v.26 no.3
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• pp.173-178
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• 2016

In this short review, the polymer electrolyte membranes consisting of polymer and Ag salts were introduced and various approaches to solve the long-term stability were summarized. In particular, utilizing $AgNO_3$ as carriers with ionic liquid, the replacement of polymer matrix as poly(ethylene phthalate) (PEP) for strong coordinative interactions with Ag ions and the introduction of $Al(NO_3)_3$ to $polymer/AgBF_4$ complexes were introduced for long-term stable facilitated olefin transport membranes. For the polymer nanocomposite membranes, the role of electron acceptors as polarizer on the surface of AgNPs and the approach to solve the low permeance were introduced.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.09a
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• pp.57-71
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• 1995

A simple mathematical model for gacilitated mass transport with a fixed site carrier membrane was derived by assuming an instantaneous, microscopic concentration (activity) fluctuation, The concentration fluctuation, developed due to reversible chemical reaction between carrier and solute, could acuse the higher chemical potential gradient and the facilitated transport. For mathematical formulation, an analogy was employed between the mass transfer for the facilitated transport with fixed site carrier membrane and the electron transfer in a parallel resistor-capacitor (RC) circuit. For the single RC model, it was assumed that a single capacitor represented the total carrier and a solute could not inter-diffuse between matrix and carrier, allowing only two diffusional pathways, This assumption was relaxed by adopting a serial combination of the parallel RC circuit. Here, a solute diffuses in two elements (matrix or carrier) can exchange its pathway, exhibiting four diffusional pathways. The current models were examined against experimental data and the agreement was exceptional.

• Membrane Journal
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• v.26 no.1
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• pp.32-37
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• 2016

The poly(vinyl alcohol) $(PVA)/AgCF_3SO_3/Al(NO_3)_3$ electrolyte membrane was fabricated to prepare for highly permeable facilitated olefin transport membrane, compared with poly(vinylpyrrolidone) $(PVP)/AgCF_3SO_3/Al(NO_3)_3$ complex. In order to examine the characteristics of $PVA/AgCF_3SO_3/Al(NO_3)_3$ membrane, we used the analytical methods such as SEM, FT-IR, and FT-Raman. The best separation performance was observed at the mole ratio of 1 : 1 : 0.01 $PVA/AgCF_3SO_3/Al(NO_3)_3$ among various $Al(NO_3)_3$ concentration. As a result, the selectivity was 12 and mixed-gas permeability was 3.5 Barrer. Furthermore, the selectivity and permeability remained constant for up to 115 h.

• Membrane Journal
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• v.24 no.6
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• pp.417-422
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• 2014

The poly(ethylene oxide) (PEO)/Ag Nanoparticles (NPs)/7,7,8,8-Tetracyanoquinodimethane (TCNQ) membrane was fabricated to obtain highly permeable facilitated olefin transport nanocomposite membrane, compared with PEO/Ag NPs/p-Benzoquinone (p-BQ) membrane. Polymer matrix, PEO and silver nanoparticle precursor $AgBF_4$ were fixed at 1 : 0.4 mole ratio and electron acceptor TCNQ content was controlled variously. And the best olefin separation performance was obtained at 1/0.4/0.004 mole ratio, and long-term separation performance was measured at this ratio. As a result, mixed-gas permeance decreased from 23 to 6 GPU, and selectivity decreased from 6 to 2 (propylene/propane) after 32 hours.

• Clean Technology
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• v.13 no.1 s.36
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• pp.79-84
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• 2007

Separation of ethylene from ethane and propylene from propane have been conducted using facilitated olefin transport membrane with SPEEK-Ag (Ag substituted sulfonated poly(ether ether ketone)). SPEEK was prepared by the sulfonation of PEEK using cone. $H_2SO_4$ and the reaction time affected the degree of sulfonation (DS) of the resulting SPEEK. SPEEK-Ag composite membrane was formed by soaking SPEEK in the polyester support into the Ag salt solution. With increasing the concentration of SPEEK in MeOH, the thickness of SPEEK on the polyester increased. The selectivity and the flux of SPEEK-Ag membrane for the separation of ethylene/ethane and propylene/propane were changed by the thickness of SPEEK layer on the top of polyester support. The anion of silver salt also affects the membrane performance.

• Membrane Journal
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• v.25 no.5
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• pp.398-405
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• 2015

Facilitated transport is considered to be a possible solution to simultaneously improve permeability and selectivity, which is challenging in normal polymeric membranes based on solution-diffusion transport only. We investigated the effect of adding mesoporous $TiO_2$ ($m-TiO_2$) upon the separation performance of facilitated olefin transport membranes comprising poly(vinyl pyrrolidone), Ag nanoparticles, and 7,7,8,8-tetracyanoquinodimethane as the polymer matrix, olefin carrier, and electron acceptor, respectively. In particular, $m-TiO_2$ was prepared by means of a facile, mass-producible method using poly(vinyl chloride)-g-poly(oxyethylene methacrylate) graft copolymer as the template. The crystal phase of $m-TiO_2$ consisted of an anatase/rutile mixture, of crystallite size approximately 16 nm as determined by X-ray diffraction. The introduction of $m-TiO_2$ increased the membrane diffusivity, thereby increasing the mixed-gas permeance from 1.6 to 16.0 GPU ($1GPU=10^{-6}cm^3$(STP)/($s{\times}cm^2{\times}cmHg$), and slightly decreased the propylene/propane selectivity from 45 to 37. However, both the mixed-gas permeance and selectivity of the membrane containing $m-TiO_2$ rapidly decreased over time, whereas the membrane without $m-TiO_2$ had more stable long-term performance. This difference might be attributed to specific chemical interactions between $TiO_2$ and Ag nanoparticles, causing Ag to lose activity as an olefin carrier.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.29-32
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• 2003

Polymer electrolyte membranes are developed for the applications to facilitated transport membranes, fuel cells and solar cells. The polymer electrolyte membranes containing silver salt show the remarkably high separation performance for olefin/paraffin mixture in the solid state; the propylene permeance is 45 GPU and the ideal selectivity of propylene/propane is 15,000. For fuel cell membranes, the effects of the presence and size of the proton transport channels on the proton conductivity and methanol permeability were investigated. The cell performance for dye-sensitized solar cells employing polymer electrolytes are measured under light illumination. The overall energy conversion efficiency reaches 5.44 % at 10 ㎽/$\textrm{cm}^2$, to our knowledge the highest value ever reported in the polymer electrolytes.

• Membrane Journal
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• v.25 no.1
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• pp.1-6
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• 2015

It was known that the polarlized surface of silver nanoparticles could be interacted revesibly with olefin molecules for facilitated olefin transport. However, it was thought that it can be regenerated by interaction between oxide surface of AgNPs and olefin molecules because the surface of the silver nanoparticles is easily oxidized in the air. In order to investigate the effect of the silver oxide, 5 wt% AgO or $Ag_2O$ was dispersed in polymer PVP solutions and 0.005~0.02% electron acceptor as TCNQ or p-BQ were added to fabricate the separation membrane. After the addition of the electron acceptor, it was expected to improve the polarity on the surface of the silver oxide and the degree of dispersion. The characteristics of the separation membrane were identified by the gas permeance, XPS and TEM.