• Membrane Journal
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• v.26 no.2
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• pp.97-107
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• 2016

This study was carried out to prepare a heterogeneous cation exchange membrane by mixing polyvinylidene fluoride (PVDF), commercial cation exchange resin and sulfonated poly(phenylene oxide)(SPPO) in order to propose an optimum condition for the preparation, and to compare its properties with commercial membrane. Study results show that the ion exchange capacity and electrical resistance were outstanding when the ratio of polymer matrix was less than 30% comparing between PVDF-IER, PVDF-SPPO and PVDF-SPPO-IER. The tensile strength was confirmed that seemed a hard look was five times greater compared to the commercial heterogeneous membrane, despite the weak durability of PVDF resin. Therefore, when chemical and mechanical properties are considered, the optimum mixing ratio between PVDF, IER and SPPO was 30 : 70, at which electric resistance was measured as $3{\sim}5{\Omega}{\cdot}cm^2$, ion exchange capacity as 0.6~1.0 meq/g, while mechanical strength was in a range of $12{\sim}15kgf/cm^2$.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.705-714
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• 1995

A new analytical luminescence method for the Eu+3 and Tb+3 ions was studied using the luminescence enhancement by the treatment of the o-phenanthroline on the nylon membrane. Compared to the specific emission intensities of the ions in aqueous(or ethanol) solution, if the aqueous ion is spotted on the nylon membrane, the luminescence intensities were extremely enhanced. There was additional enhancement effect of the luminescence intensities of the ions on the nylon membrane, if the ion on the nylon membrane is treated with o-phenanthroline. Based on the luminescence enhancement, the detection limits were lowered by more than 7 order of magnitude compared to that of solution sample, and also lowered by about 1 order of magnitude compared to that of previous TLC method. The dynamic ranges and correlation coefficients of the calibration curves near the detection limit were 2∼3 order and ∼0.99, respectively. It was also shown that the luminescence intensity was in its maximum when the ion on the nylon is treated with ∼4 mole ratio of o-phenanthroline. The energy-transfer mechanism was explained for the theoretical background of the luminescence enhancement.

• Rapid Communication in Photoscience
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• v.1 no.2
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• pp.58-58
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• 2012

• Journal of the Korean Chemical Society
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• v.26 no.6
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• pp.427-429
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• 1982

• Membrane Journal
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• v.18 no.2
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• pp.176-184
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• 2008

Nano-porous ceramic membranes was synthesized by the sol-gel method. Gas permeation of hydrogen and nitrogen was determined by single composition gas. Pore size $0.1{\mu}m$ and porosity 32% of flat type ${\alpha}-Al_2O_3$ substrate was manufactured. An intermediate ${\gamma}-Al_2O_3$ layer with pore size of 4 nm was formed by dip-coating. Polymeric silica sol was synthesized by acid catalyzed hydrolysis and condensation of tetra-ethyl-ortho-silicate. Supported membranes on alumina were prepared by dipping and calcining. He, $N_2$ permeation experiments with nanoporous sol-gel modified supported ceramic membranes were peformed to determine the gas transport characteristics. $He/N_2$ permselectivity around $100{\sim}160$ and helium permeation in the order of $10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ were measured in the temperature range of $303{\sim}363K$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.247-251
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• 1999

In spite of various bio-functionalities of chitosan, the effects in vivo were still ambiguous because of its low absorption on organism. Therefore, chitosan oligosaccharides (COSs) are necessary to elucidate for an efficient utilization in vivo. COSs were prepared from chitosan using ultrafiltration membrane enzymatic reactor system with MWCO (molecular weight cut-off) 3,000 Da of membrane. Calcium absorption accelerating effect using COSs was examined by two methods, in vitro and in vivo. In vitro experiment, calcium absorption by the addition of COSs in a mixture solution of calcium and phosphate was higher approximately $50\%$ than that by control. In vivo using rats, group taken the diet contained $1\%$ COSs anil calcium chloride decreased about $75\%$ of calcium content excreted from feces, and then, showed about $15\%$ increase in breaking force of femur. These results demonstrated that COSs definitely involved in calcium metabolism in vivo.

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.413-422
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• 2015

Proton exchange membrane (PEM), which transfers proton from the anode to the cathode, is the key component of the proton exchange membrane fuel cell (PEMFC). Nafion is widely used as PEM due to its high proton conductivity as well as excellent chemical and physical stabilities. However, its high cost and the environmental hazards limit the commercial application in PEMFCs. To overcome these disadvantages, various alternative polymer electrolytes have been investigated for fuel cell applications. We used densely sulfonated polymers to maximize the ion conductivity of the corresponding membrane. To overcome high swelling, dipole-dipole interaction was used by introducing nitrile groups into the polymer backbone. As a result, physically-crosslinked membranes showed improved swelling ratio despite of high water uptake. All the membranes with different hydrophilic-hydrophobic compositions showed higher conductivity, despite their lower IEC, than that of Nafion-117.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.304-310
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• 1978

The relative permeabilities, distribution coefficients and diffusion coefficient of some salts which are important components in blood plasma through a poly(HEMA) membrane were measured. The crosslinker which was used for preparing the membrane was tetraethylene glycol dimethacrylate(TEGDMA), the weight percentage of the latter was about 2.8. We found that the diffusion coefficients ($D_m$) of the solutes decrease exponentially with increasing molecular weight, and also that $D_m$'s decrease linearly (except urea) with cylindrical radius (a). These facts were explained by a sieve pore flow model. The relative permeability and diffusion coefficient of urea at various temperature were larger than those of other solutes such as glycine, ${\beta}$-alanine, D-glucose, saccharose and maleic acid. The result indicates that the poly(HEMA) membrane might be suitable for hemodialysis application.

• Journal of the Korean Chemical Society
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• v.20 no.6
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• pp.486-493
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• 1976

The PVC mixed silver iodide pellet was prepared by means of the Infrared Pellet presser and the pellet was used as an indicating membrane electrode, to measure the potentials for various silver ion activities, ranging from $10^{-1}$ to $10^{-6}$ M. The potential responses to silver ion activities were linear and the slope was much close to Nernstian relation as compared with that of the pure silver iodide pellet membrane electrode and the PVC coated silver iodide pellet membrane electrode. The mechanical property and chemical durability of this electrode were found much better than the others. This electrode did not show significant response to the other except silver ion, but had good response to halide ions, i.e., iodide, chloride, bromide and cyanide ions, in the concentration range $10^{-1}$ to $10^{-6}$ M. This electrode could be used as an indicating electrode in potentiometric titrations of single halide ion and also halide mixture with standard solution of silver nitrate.

• Membrane Journal
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• v.16 no.1
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• pp.68-76
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• 2006

This is the research about the concentration of trace citrus flavor components in water by pervaporation. We have investigated the permeation characteristics depending on the material and formation of membranes using four siloxane-based polymer composite membranes. We have also chosen the optimal membrane and investigated the permeation characteristics depending on the feed temperature, concentration and flow rate. And then it has been analyzed by using resistance-in series model. In the permeation experiment of citrus essence aroma model solution through the four siloxane-based polymer composite membranes, PVDF/POMS membranes have showed the best flavor flux and enrichment factor. As a result of the permeation experiment depending on the feed temperature, concentration and flow rate, we can find that as the feed temperature and concentration increase, the flavor flux increases while the enrichment factor decreases. And the flavor flux and enrichment factor increased as the flow rate increases.