• Journal of Electrochemical Science and Technology
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• v.14 no.3
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• pp.283-292
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• 2023

Currently, spray coating has attracted interest in the mass production of anode catalyst layers for proton exchange membrane water electrolysis (PEMWE). The solvent in the spray ink is a critical factor for the catalyst dispersion in ink, the microstructure of the catalyst layer, and the PEMWE performance. Herein, various pure organic solvents were examined as a substitute for conventional isopropanol-deionized water (IPA-DIW) mixture for ink solvent. Among the polar solvents that exhibited better IrO₂ dispersion over nonpolar solvents, 2-butanol (2-BuOH) was selected as a suitable candidate. The PEMWE single cells were fabricated using 2-BuOH at various ionomer contents, spray nozzle types, and drying temperatures, and their performance was compared to the cells fabricated using a conventional IPA-DIW mixture. The PEMWE single cells with 2-BuOH solvent showed good performances comparable to the conventional IPA-DIW mixture case and highly durable performances under accelerated degradation tests.

• Membrane Journal
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• v.23 no.2
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• pp.170-175
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• 2013

Poly (vinyl alcohol) (PVA) solution containing the glutaraldehyde (GA) as a crosslinking agent was coated onto the polyacrylonitrile (PAN) hollow fiber membrane as the supporter. Pervaporation experiments were carried out to characterize the prepared PVA/PAN composite membrane for water-isopropyl alcohol mixture. The flux and separation factor were measured at 30, 50, $90^{\circ}C$ for the feed mixture of aqueous 85 wt% IPA solution with varying the reaction temperature and composition of coating solutions. Typically the flux showed 1,870 $g/m^2{\cdot}hr$ at $90^{\circ}C$ feed mixture and the coating concentration of 3.5 wt% and the highest separation factor of 804 was obtained at $30^{\circ}C$ feed mixture and the coating concentration of 7 wt% as well.

• Membrane Journal
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• v.17 no.1
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• pp.61-66
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• 2007

A zeolite membrane shows better thermal, mechanical and chemical stabilities than a polymer membrane. Water was separated from iso-propyl alcohol (IPA)/water mixtures by pervaporation using the NaY zeolite membrane synthesized in the laboratory. The effects of a mole fraction of IPA in the feed solution and an operating temperature were studied on the permeation flux behavior and the separation factor of water with respect to IPA. As a mole fraction of IPA increased, the water flux as well as the separation factor decreased. As the experimental temperature increased, the water permeation flux increased while the separation factor decreased. For IPA/water binary mixtures, the water flukes through the NaY zeolite membrane were observed to be $1.9{\times}10^2{\sim}3.5{\times}10^3\;g/m^2{\cdot}hr$ and the separation factors were found to be $7.0{\times}10^2{\sim}2.0{\times}10^4$.

• Membrane Journal
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• v.28 no.4
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• pp.279-285
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• 2018

The pervaporation separation of isopropanol/water mixture was carried out on a series of chemically cross-linked poly(vinyl alcohol)(PVA) composite membranes. The membranes were prepared by casting three kinds of PVA solutions with varying concentrations of PVA and GA onto polyacrylonitrile (PAN) support followed by thermal cross linking. As the PVA concentration increased, the flux decreased but separation factor was increased. It was confirmed that the composite membrane coated with PVA-3 (98~99% hydrolyzed) at a concentration of 7 wt% PVA and 20 wt% glutaraldehyde (GA) exhibited a flux of $209g/m^2h$ and a separation factor of more than 100. The submerged module test was carried out with controlled feed tank temperature and IPA concentration of the feed solution. The continuous concentration of IPA solution was increased from 90% to 99% after 60 h.

• Membrane Journal
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• v.16 no.1
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• pp.25-30
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• 2006

The NaA zeolite membrane was synthesized on the surface of a porous ${\alpha}$-alumina support from the reaction solution composed of 1Si : 1Na : 4Na $6H_{2}O$. The pervaporation performance of the synthesized NaA zeolite membrane was investigated for the iso-propyl alcohol (IPA) aqueous solution according to the different feed concentration and the different operating temperature. The total flux decreases by increasing the feed IPA concentration and increases by increasing the temperature. The total flux was about $4.0{\times}10^3g/m^2\;hr\;at\;60^{\circ}C$ and 0.6 mole fraction of IPA and the separation factor was $1.8{\times}10^7\;at\;60^{\circ}C$ and 0.8 mole fraction of IPA. The separation performance of water through the NaA membrane was found to be superior to that obtainable with a distillation process just by comparison of the vapor-liquid equilibrium data.

• Membrane Journal
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• v.33 no.6
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• pp.369-376
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• 2023

In this study, the alternative to the energy-intensive conventional vacuum distillation process, an eco-friendly and energy-efficient pervaporation separation was employed in 1,2 hexane diol/water (HDO/water) mixture. The crosslinked PVA-glutaraldehyde was coated inside the alumina hollow fiber membrane (Al-HF). In the HDO/IPA pervaporation separation, optimization of the membrane concerning PVA/GA ratio, curing temperature, and pervaporation operating condition were performed. In the long-term stability test, the sustainable pervaporation separation performance giving flux in the range of 1.90~2.16 kg/m²h, and water content in permeate was higher than 99.5% (separation factor = 68) was obtained from the PVA/GA (molar ratio = 0.08, curing temperature = 80℃) coated Al-HF membrane from HDO/water (25/75, w/w, %) mixture at 40℃. Therefore, this work provides potential and inspiration for PVA-based membranes to mitigate excessive energy requirements in HDO/water separation by pervaporation.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.441-449
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• 2019

In this study, cellulose acetate (CA) / nylon66 (NYL66) (95/5) blend membranes with different thicknesses were prepared by a solvent evaporation method. The effects of membrane thickness (almost $7-25{\mu}m$), feed concentration (70-95 wt.% isopropanol), and feed temperature ($30-60^{\circ}C$) were investigated on the performance of membrane in the separation of isopropanol-water mixtures. With regard to the results of sorption experiments, it was found that the increase of feed temperature enhanced the overall sorption while by increasing feed concentration, the overall sorption passed through a maximum value at 70 wt. % isopropanol (IPA). The best separation factor 3080.51 was gained at high isopropanol concentration 95 wt.%, low feed temperature $30^{\circ}C$, and high membrane thickness $24.62{\mu}m$. Regarding the pervaporation separation index, the obtained results showed that proper values for the thickness of membrane, feed temperature, and isopropanol concentration in feed were $24.62{\mu}m$, $40^{\circ}C$, and 70 wt.%, respectively.

• Resources Recycling
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• v.7 no.4
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• pp.35-42
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• 1998

Surface mount technology is the biggest theme in the area of deιIronic component. To miniatunze an electronic component, s such as ferrite chip inductor, the cer뼈lic wet process for green-sheet lamination and/or screen printing method through a s solvent medium system is widely used. The preparation and characterization of NiCuZn Ferrite (NCZF) shurry and the green s sheet using the water mixed binder system has been studied. The 21 vol% of NCZF slurry was prepared by a ball milling. The p polyacrylic vinyl copolymer (Mw; 60,000) was used as a binder. Th$\xi$ mixture of distilled water, isopropyl alcohol (IPA) and 2l butoxy ethanol was used as a dispersion medium. The water content of medium varied from about 40% to 80%. As the results. Thc disp$\xi$rston stability of the NCZF slurry was attributed to the free polymer rather than the electrostatic force of the particle. T The viscosity of the NCZF slurry was greatly depended on the ratio of water content in the medium.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.251-251
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• 2016

For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. Wastewaters are consisting of complex mixture of different inorganic and organic compounds and some of them can be toxic, hazardous and hard to degrade. These effluents are mainly treated by conventional technologies such are aerobic and anaerobic treatment and chemical coagulation. But, these processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that could be show higher purification results. Among them, boron doped diamond (BDD) attract attention as electrochemical electrode due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD on Nb, Ta, W and Si substrates, but, their application in effluents treatment is not suitable due to high cost of metal and low conductivity of Si. To solve these problems, Ti has been candidate as substrate in consideration of cost and property. But there are adhesion issues that must be overcome to apply Ti as BDD substrate. Al, Cu, Ti and Nb thin films were deposited on Ti substrate to improve adhesion between substrate and BDD thin film. In this paper, BDD films were deposited by hot filament chemical vapor deposition (HF-CVD) method. Prior to deposition, cleaning processes were conducted in acetone, ethanol, and isopropyl alcohol (IPA) using sonification machine for 7 min, respectively. And metal layer with the thickness of 200 nm were deposited by DC magnetron sputtering (DCMS). To analyze microstructure X-ray diffraction (XRD, Bruker gads) and field emission scanning electron microscopy (FE-SEM, Hitachi) were used. It is confirmed that metal layer was effective to adhesion property and improved electrode property. Electrochemical measurements were carried out in a three electrode electrochemical cell containing a 0.5 % H2SO4 in deionized water. As a result, it is confirmed that metal inter layer heavily effect on BDD property by improving adhesion property due to suppressing formation of titanium carbide.