• Membrane Journal
• /
• v.14 no.3
• /
• pp.201-206
• /
• 2004

The stability of the prepared silica membrane by chemical vapor deposition (CVD) method in the HI-$H_2O$ gaseous mixture was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical IS process. Porous $\alpha$-alumina having pore size of 100 nm was modified by the different CVD temperature using tetraethoxysilane as the Si source. The CVD temperature was $700^{\circ}C$, $650^{\circ}C$, and $600^{\circ}C$. The $H_2$/H$_2$ selectivities of the modified membranes which were measured by single-component permeation experiment showed 43.2, 12.6, and 8.7 at $600^{\circ}C$ for the M1 (CVD temperature was $700^{\circ}C$), M2 (CVD temperature was $650^{\circ}C$) and M3 membranes (CVD temperature was $600^{\circ}C$), respectively. Stability experiment in the HI-$H_2O$ gaseous mixture was carried out at $450^{\circ}C$. The prepared silica membrane at $600^{\circ}C$ of CVD temperature was more stable than that at the other CVD temperature.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.176-183
• /
• 2016

This study relates to a polymer electrolyte membrane for improved performance fuel cell, were researched with respect to properties required for driving a fuel cell. The bis(4-fluorophenyl)phenyl phosphine oxide was sulfonated using fuming sulfuric acid. Synthetic hydrophilic oligomer and the hydrophobic oligomer and the block copolymers were prepared via aromatic nucleophilic substitution polycondensation. A block copolymer structure and degree of sulfonation was analyzed by $^1H$-NMR and gel permeation chromatography(GPC) analysis. Thermal stability was confirmed by thermogravimetric analysis(TGA), block copolymer was stable at high temperature(>$200^{\circ}C$), The ion conductivity was measured in order to demonstrate the performance of fuel cell. Synthesis membrane was the increase of temperature was improved conductivity up to 58 mS/cm due to the influence of the developed ion clusters. The phase separation of the polymer was observed to make AFM analysis.

• Membrane Journal
• /
• v.28 no.2
• /
• pp.129-135
• /
• 2018

ZIFs (Zeolitic imdazolate frameworks) have attracted great attention as membrane materials in recent years due to their high chemical and thermal stability, high specific surface area and adjustable pore structure. In this study, ZIF-8 membranes were synthesized by in-situ growth method on two different support materials (${\alpha}$-alumina and YSZ) and their $H_2/CO_2$ gas permeation characteristics were investigated. In order to synthesize defect-free ZIF-8 layer, YSZ support required less synthesis time than ${\alpha}$-alumina support due to smaller pore size. After in-situ growth for 3 h, ZIF-8 membranes prepared on both YSZ and ${\alpha}$-alumina supports showed $H_2/CO_2$ selectivity of about 10.

• Journal of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.377-383
• /
• 1990

Three kinds of hydrogel membranes were prepared by the copolymerization of 2-hydroxyethylmethacrylate (HEMA) with acrylamide, N, N-dimethylamide and methylmethacrylate in the presence of solvent and crosslinker respectively. The equilibrium water content, relative permeability and partition coefficient of the membranes for alcohol solutes were measured. It has been found that the permeation of organic solute occurs through the water-filled regions in the hydrogel membrane, and that the gpermeability coefficient of organic solute depends on the molecular size. But the permeability of organic solute was controlled by the interaction of solute-membrane at the low water content. By the partition data, it has been shown that the partition of solute is only controlled by hydrophobic interaction between solute and membrane. The diffusion coefficient data were interpreted on the basis of water-solute interaction. It has been found that the diffusion of organic solute is determined by the free volume of water in the membrane, and that hardly depends on polarity-polarizability and hydrogen bonding ability between water and solute.

• Membrane Journal
• /
• v.18 no.3
• /
• pp.226-233
• /
• 2008

PTMSP/PMMH dendrimer composite membranes were made by dispersing $0{\sim}20$ wt% (based on polymer content) PMMH dendrimer nanoparticles in the PTMSP casting solution. The effect of PMMH dendrimer on gas permeability characteristics of the composite membranes was investigated. The permeabilities of $H_2,\;N_2,\;CO_2$, and $CH_4$ decreased as the PMMH dendrimer content within PTMSP increased. The permeabilities of different gases except hydrogen in PTMSP/PMMH dendrimer membranes follow the order: $N_2\;<\;CH_4\;<\;CO_2$ which are consistent with the order of critical temperature ($N_2\;<\;CH_4\;<\;CO_2$). The selectivities of gases for $N_2$ increased as the PMMH dendrimer content within PTMSP increased. The $CO_2/N_2$ selectivity increased from 5.6 up to 16.9.

• Membrane Journal
• /
• v.25 no.2
• /
• pp.115-122
• /
• 2015

$SiO_2{\cdot}B_2O_3$ was prepared by trimethylborate (TMB)/tetraethylorthosilicate (TEOS) mole ratio 0.01 at $800^{\circ}C$. PDMS[poly(dimethysiloxane)]-$SiO_2{\cdot}B_2O_3$ composite membranes were prepared by adding porous $SiO_2{\cdot}B_2O_3$ to PDMS. To investigate the characteristics of PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane, we observed PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane using TG-DTA, FT-IR, BET, X-ray, and SEM. PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was studied on the permeabilities of $H_2$ and $N_2$ and the selectivity ($H_2/N_2$). Following the results of TG-DTA, BET, X-ray, FT-IR, $SiO_2{\cdot}B_2O_3$ was the amorphous porous $SiO_2{\cdot}B_2O_3$ with $247.6868m^2/g$ surface area and $37.7821{\AA}$ the mean of pore diameter. According to the TGA measurements, the thermal stability of PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was enhanced by inserting $SiO_2{\cdot}B_2O_3$. SEM observation showed that the size of dispersed $SiO_2{\cdot}B_2O_3$ in the PDMS-$SiO_2{\cdot}B_2O_3$ composite membrane was about $1{\mu}m$. The increasing of $SiO_2{\cdot}B_2O_3$ content in PDMS leaded the following results in the gas permeation experiment: the permeability of both $H_2$ and $N_2$ was increased, and the permeability of $H_2$ was higher than $N_2$, but the selectivity($H_2/N_2$) was decreased.

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