• Journal of the Korean institute of surface engineering
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• v.51 no.5
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• pp.277-290
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• 2018

In this study, Pd-Ni-Ag alloy hydrogen separation membranes were fabricated by Pd/Ag/Pd/Ni/Pd multi-layer sputter deposition on the modified MIM(Metal Injection Molding)-PSS(Porous Stainless Steel) support and followed heat treatment. Nickel, used as an alloying element in Pd alloy membranes, is inexpensive and stable material in a hydrogen isotope environment at high temperature up to 1123 K. Hydrogen perm-selectivity of Pd-Ni-Ag alloy membranes is affected not only by composition of membrane films but also by other factors such as surface properties of PSS support, microstructure of membrane films and inter-diffused impurities from PSS support. In order to clarify the effect of surface Ni composition on hydrogen perm-selectivity of Pd-Ni-Ag alloy membranes, the other effects were significantly minimized by the formation of dense and homogeneous Pd-Ni-Ag alloy membranes. Hydrogen permeation test showed that hydrogen permeability decreased from $7.6{\times}10^{-09}$ to $1.02{\times}10^{-09}mol/m{\cdot}s{\cdot}Pa^{0.5}$ as Ni composition increased from 0 to 16 wt% and the selectivity for $H_2/N_2$ was infinite.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.2
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• pp.177-183
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• 2020

To utilize hydrogen energy, high-yield, high-purity hydrogen needs to be produced; therefore, hydrogen separation membrane studies are being conducted. The membrane reactor that fabricates hydrogen needs to have high hydrogen permeability, selective permeability, heatresistant and a stable mechanical membrane. Dense membranes of Pd and Pd alloys are usually used, but these have drawbacks associated with high cost and durability. Therefore, many researchers have studied replacing Pd and Pd alloys. Dense TiN membrane is highly selective and can separate high-purity hydrogen. The porous alumina has a high permeation rate but low selectivity; therefore, separating high-purity hydrogen is difficult. To overcome this drawback, the two materials are combined as composite reclamations to produce a separation membrane with a high penetration rate and high selectivity. Accordingly, TiN-alumina was manufactured using a high-energy ball mill. The TiN-alumina membrane was characterized by X-ray diffraction analysis, scanning electron microscopy, and energy dispersive spectroscopy. The hydrogen permeability of the TiN-alumina membrane was estimated by a Sievert-type hydrogen permeation membrane apparatus. Due to the change in the diffusion mechanism, the transmittance value was lower than that of the general TiN ceramic separator.

• Journal of the Korean institute of surface engineering
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• v.42 no.5
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• pp.232-239
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• 2009

This study presented the effect of membrane thickness on hydrogen permeability. Microvoids on the surface of the membrane should not exist for the exact values of hydrogen permeability. Pd-Cu-Ni hydrogen alloy membranes were fabricated by Ni powder sintering, substrate plasma pretreatment, sputtering and Cu reflow process. And this leaded to void-free surface and dense film of Pd-Cu-Ni hydrogen alloy membrane. Hydrogen permeation test showed that hydrogen permeability increased from 2.7 to $15.2ml/cm^2{\cdot}min{\cdot}atm^{0.5}$ as membrane thickness decreased from 12 to $4{\mu}m$. This represented the similar trend as a hydrogen permeability of pure palladium membrane based on solution-diffusion mechanism.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.264-270
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• 2010

Recently, the most promising methods for high purity hydrogen production are membranes separation such as polymer, metal, ceramic and composites. It is well known that Pd and Pd-alloys membranes have excellent properties for hydrogen separation. However, it has hydrogen embrittlement and high cost for practical applications. Therefore, most scientists have studied new materials instead of Pd and Pd-alloys. On the other hand, TiN powders are great in resistance to acids and chemically stable under high operating temperature. In order to get specimens for hydrogen permeation, the TiN powders synthesized were consolidated together with Co, Ni powders by hot press sintering (HPS). During the consolidation of powders at HPS, heating rate was 10 K/min and the pressure was 10 MPa. It was characterized by XRD, SEM. Also, we estimated the hydrogen permeability by Sievert's type hydrogen permeation membrane equipment.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.114.1-114.1
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• 2010

A highly performed Pd-based hydrogen membrane has prepared successfully on a modified porous nickel support. The porous nickel support modified by impregnation method of $Al(NO_3)_3{\cdot}9H_2O$ (Aldrich Co.) over the nickel powder showed a strong resistance to hydrogen embrittlement and thermal stability. Plasma surface modification treatment was introduced as a pre-treatment process instead of conventional HCl wet activation. Ceramic barrier was coated on the external surface of the prepared nickel supports to prevent intermetallic diffusion and to enhance the affinity between the support and membrane. Palladium and copper were deposited at thicknesses of $4\mu}m$ and $0.5{\mu}m$, respectively, on a barrier-coated support by DC sputtering process. The permeation measurement was performed in pure hydrogen at $400^{\circ}C$. The single gas permeation of our membrane was two times higher than that of the previous membrane which do not have ceramic barrier.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.4
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• pp.359-366
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• 2008

Hydrogen as a high-quality and clean energy carrier has attracted renewed and ever-increasing attention around the world in recent years, mainly due to developments in fuel cells and environmental pressures including climate change issues. In this processes for hydrogen production from fossil fuels, separation and purification is a critical technology. $(Ni_{60}-Nb_{40})_{95}-Pd_5$ alloy ingots were prepared by arc-melting the mixture of pure metals in an Ar atmosphere. Melt-spun ribbons were produced by the single-roller melt-spinning technique in an Ar atmosphere. Amorphous structure and thermal behavior were characterized by XRD and DSC. The permeability of the $(Ni_{60}-Nb_{40})_{95}-Pd_5$ amorphous alloy membrane was characterized by hydrogen permeation experiments in the temperature range 623 to 773 K and pressure of 2 bars. The maximum hydrogen permeability was $3.54{\times}10^{-9}[mol{\cdot}m^{-1}s^{-1}{\cdot}pa^{-1/2}]$ at 773 K for the $(Ni_{60}-Nb_{40})_{95}-Pd_5$ amorphous alloy.

• Membrane Journal
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• v.21 no.3
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• pp.290-298
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• 2011

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane. The hydrogen permeation characteristics of Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane have been investigated in the pressure range 1-3 bar under pure hydrogen and hydrogen mixture gas with carbon dioxide and carbon monoxide at $450^{\circ}C$. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was $5.36mL/min/cm^2$ for a Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane (thick: 0.5 mm) using pure hydrogen as the feed gas. In addition, hydrogen fluxes were 4.46, 5.20, $3.91mL /min/cm^2$ for$V_{53}Ti_{26}Ni_{21}$ alloy membrane using $H_2/CO_2$, $H_2/CO$ and $H_2/CO_2/CO$ as the feed gas respectively. Therefore, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure irrespective of temperature and pressure when $H_2/CO_2$, $H_2/CO$ and $H_2/CO_2/CO$ mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD results after permeation test that the Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane had good stability and durability for various mixtures feeding condition.

• 한국전기화학회:학술대회논문집
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• 2001.06a
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• pp.27-32
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• 2001

• Korean Membrane Journal
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• v.5 no.1
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• pp.68-74
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• 2003

Methane steam reforming (MSR) reaction for hydrogen production was studied in a membrane reactor (MR) using two tubular membranes, one Pd-based and one of porous alumina. A higher methane conversion than the thermodynamic equilibrium for a traditional reactor (TR) was achieved using MRs. The experimental temperature range was 350-500$^{\circ}C$; no sweep-gas was employed during reaction tests to avoid its back-permeation through the membrane and the steam/methane molar feed ratio (m) varied in the range 3.5-5.9. The best results (the difference between the MR conversion and the thermodynamic equilibrium was of about 7%) were achieved with the alumina membrane, working with the highest steam/methane ratio and at 450$^{\circ}C$. Silica membranes prepared at KRICT laboratories were characterized with permeation tests on single gases (N$_2$, H$_2$ and CH$_4$). These membranes are suited for H$_2$ separation at high temperature.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.269-273
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• 1996

We investigated the effects of ginseng glycosides and their aglycones on processes of single ion channel formation and channel properties. The glycosides, Rg, and Rb, , and their aglycones, 20-(S)-protopanaxatriol (PT) and 20-(S)-protopanaxadiol (PD) increased the membrane permeability for ions. PT, PD, Rg1, and Rb1; at concentrations of 0.5, 3.0, 10.0 and 30.0 $\mu\textrm{g}$/ml respectively; Induced single ion channel fluctuations with the life times in the range of 0.1~1005 in open states and conductances from 5 to 30 pS in 1 M KCI. At high concentrations of these substances, rapid fluctuations of transmembrane ion current with amplitude from hundred pS to dozen nS were observed. Against other substances, ginsenoside Rbl began to increase the membrane conductance at concentration of about 60 $\mu\textrm{g}$/ml without fluctuation of single ion channel. Membranes treated with PT, PD, Rg1 and Rb1 are more permeable to K+, than to Cl while zero current membrane potentials with 10 gradients of KCI were 12, 16, 8, 25 mV respectively. Key words : Membrane conductance, single ion channel, ginsenosides.