• Membrane Journal
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• v.32 no.5
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• pp.336-347
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• 2022

Reverse electrodialysis (RED) is one of the promising eco-friendly renewable energy technologies which can generate electricity from the concentration difference between seawater and freshwater by using ion-exchange membranes as a diaphragm. The ion-exchange membrane is a key component that determines the performance of RED, and must satisfy requirements such as low electrical resistance, high permselectivity, excellent durability, and low manufacturing cost. In this study, pore-filled anion-exchange membranes were fabricated using porous polymer substrates having various thicknesses and porosity, and the effects of ion-exchange polymer composition and membrane thickness on the power generation performance of RED were investigated. When the electrical resistance of the ion-exchange membrane is sufficiently low, it can be confirmed that the RED power generation performance is mainly influenced by the apparent permselectivity of the membrane. In addition, it was confirmed that the apparent permselectivity of the membranes can be improved through IEC, crosslinking degree, membrane thickness, surface modification, etc., and the optimum condition must be found in consideration of the trade-off relationship with electrical resistance.

• Membrane Journal
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• v.21 no.3
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• pp.299-305
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• 2011

This study deals with the preparation of polymeric electrolyte membranes having high durability for the application of fuel cells. The membranes under investigation were prepared the impregnation to porous polyethylene membranes with poly(vinyl alcohol)(PVA), poly(styrene sulfonic acid-co-maleic acid), and (PSSA-MA)3-(trihydroxysilyl)-1-propanesulfonic acid (THS-PSA). To characterize the resulting membranes, the water contents, the contact angles, FT-IR, the proton conductivity and the the modulus were measured. The proton conductivity of 30% content of THS-PSA at $55^{\circ}C$ gave excellent $1.27{\times}10^{-1}S/cm$ and the mechanical strength was improved 7 times higher up to the THS-PSA content 15%, as a result, the durability was elevated extensively.

• Membrane Journal
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• v.25 no.1
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• pp.15-26
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• 2015

In this study, porous metal (O.D. = 10 mm, length = 10 mm, 316 L SUS, Mott Corp.) and ${\alpha}$-alumina tube (O.D. = 10 mm, length = 50 mm, Pall, German) support was modified with suspension sols, which were consisted of $3{\sim}4{\mu}m$ and 150 nm size of ${\alpha}$-alumina particle in the water or silica-zirconia colloidal sol. The porous support was fabricated by dip coating method for 5 seconds with suspension of alumina particles. After drying at $100^{\circ}C$ for 1 h, it was calcined at $550^{\circ}C$ for 30 min. It was repeated several times in order to decrease big pore on support. The surface roughness and largest pore size on the porous support was decreased by increasing coating times with $3{\sim}4{\mu}m$ size of ${\alpha}$-alumina particle and alumina coating with 150 nm size of ${\alpha}$-alumina particle served as further smoothening the surface and decreasing the pore size of the substrate. And the silica-zirconia membranes were successfully prepared on the modified porous metal and ${\alpha}$-alumina supports, and showed hydrogen permeance in the range of $1.8-8.4{\times}10^{-4}mol{\cdot}m^{-2}{\cdot}s^{-1}{\cdot}Pa^{-1}$ and $3.3-5.0{\times}10^{-5}mol{\cdot}m^{-2}{\cdot}s^{-1}{\cdot}Pa^{-1}$, respectively.

• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.1-7
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• 2023

Gas separation technology becomes more useful because key gases such as H₂ and CO₂ regarding renewable energy resources and environmental pollutant can be effectively extracted in mixed gases. For reducing energy consumption on gas separation, membrane and adsorption processes are widely used. In both processes, porous materials are needed as membrane and adsorbent. In particular, metal-organic frameworks (MOFs), one class of the porous materials, have been developed for the purpose of gas adsorption and separation. While the number of the MOF structures is increasing due to chemical and structural tunability, good MOF membranes and adsorbents have been rarely reported by trial-and-error experiments. To accelerate the discovery of high-performing porous materials that can separate H₂ and CO₂, a high-throughput computational screening technique was used as efficient skill. This review introduces crucial studies of porous materials and the high-throughput computational screening works focusing on gas separation of H₂ and CO₂.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.43-44
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• 1996

Water-swollen-hydrogel membranes for gas separation were prepared by dipcoating and thermal crosslinking of poly(vinylalcohol) (PVA) - poly(acrylacid) (PAA) blends on asymmetric porous polyetherimide(PEI) supporters. The polyetherimide supporters, prepared by phase inversion of polyetherimide solutions in N-methylpyrrolidone(NMP) (composition of PEI/NMP=25/75), had good heat and chemical resistane. The coating materials with different blending ratios of PVA/PAA(=90/10, 80/20, 70/30) were characterized with differential scanning calorimetry (DSC), infrared spectroscopy(IR) and the water swelling ratios. The permeabilities and the separation factors of carbon dioxide through these membranes were measured by a mass flow meter and gas chromatograph at different temperatures, respectively, under a vacuum mode of downstream.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.605-608
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• 2011

Hybrid composite membranes were prepared by coating poly(ethylene oxide) and $SiO_2$ particles onto the porous polypropylene nonwoven matrix. Gel polymer electrolytes prepared by soaking the hybrid composite membranes in an organic electrolyte solution exhibited ionic conductivities higher than $1.1{\times}10^{-3}Scm^{-1}$ at room temperature. Dyesensitized solar cell (DSSC) employing the hybrid composite membrane with PEO and 10 wt % $SiO_2$ exhibited an open circuit voltage of 0.77 V and a short circuit current of 10.78 $mAcm^{-2}$ at an incident light intensity of 100 $mWcm^{-2}$, yielding a conversion efficiency of 5.2%. DSSC employing the hybrid composite membrane showed more stable photovoltaic performance than that of the DSSC assembled with liquid electrolyte.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.758-760
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• 2008

Nanoporous AAO (Anodic Aluminum Oxide) membranes have many advantages as a template for variety of magnetic materials. Materials can be embedded into the pores by electrodeposition, sputtering or magnetic-field-assisted infiltration of magnetic nanoparticles. This work focuses on the fabrication of the magnetic structures in the AAO templates by electrodeposition. Our method allows the controlled growth of Co nanostructures within the porous alumina membrane in the form of dots, rods and long wires. The shape of Co nanostructures has been investigated by field emission scanning electron microscope (FESEM). The magnetic hysteresis loops of Co nanostructures were measured using SQUID at 5 K and 300 K. The magnetic properties of the Co nanostructures are proportional to their aspect ratios and can be controlled by changing the aspect ratios.

• Korean Membrane Journal
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• v.10 no.1
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• pp.1-7
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• 2008

Polystyrene-co-divinylbenzene (PS-co-DVB) asymmetric membranes were prepared. In order to control their structure and mechanical properties the degree of cross-linking and the composition of casting solution were varied. The rubber added PS-DVB membranes was also prepared to overcome the mechanical limitation of cross-linked membrane, and their mechanical properties were investigated. It was revealed that the concentration of polymer in the casting solution affected the determination of skin formation. When the PS-co-DVB membrane consists of styrene-butadiene (SB) rubber or liquid polybutadiene (PBD), the structures formed showed that the PS content in the PS/DVB system played an important role in determining the porous sublayer structure.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.495-497
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• 2013

SiC-$Y_2O_3$ porous composites were fabricated using $Y_2O_3$ powders synthesized by sol-gel process to control physical and thermo-chemical properties. $Y_2O_3$ powders were mixed with SiC powders by co-pressing with HPCS (hydridopolycarbosilane) binder at moderate temperature. The properties of membranes were characterized by XRD, FE-SEM, and BET surface analysis. Hydrogen permeability was performed at various temperatures.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.129-132
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• 2003

Silica/SUS composite membranes were prepared for CO removal from products of methanol steam reforming. A support was prepared by coating Ni powder of sub-micron and SiO$_2$ sols of particle size of 500nm and 150nm in turns on a porous stainless steel (SUS) substrate. Silica top layer was coated on the modified support using colloidal sol with nanoparticle. As a result of mixture gas permeation test of silica composite membrane using H$_2$(99%)/CO(1%), CO concentration of 10000 ppm was reduced to under 81 ppm, which is acceptable in PEMFC anode gas specification. Permeation mechanism through the membrane was mainly molecular sieving.