• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.16-19
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• 1996

Separation with synthetic membrane have become increasingly important processes in many fields. In the most application of membrane process, polymer membrane is used. the main advantage of polymers as a material for membrane preparation is the relative simplicity of this film formation which enables one to obtain rather high permeability rates. However, polymeric membranes have several limitations, such as high temperature instability, swelling and decomposition in organic solvent, et. al.. These limitations can be overcome by inorganic membrane. At the present time, commercially available inorganic membranes have pore diameters ranging 5nm to 50mm, and the predominant flow regime in such membrane is Knudsen diffusion. Since the Knudsen permeability is directly proportional to the molecular velocity, gases can be separated due to their molecular masses. However, this separation mechanism is only of important for light gases such as H2 and He. Other separation mechanisms like surface diffusion, active diffusion can play an important role only with very small pore diameters(2nm) and give rise to large permselectivities. Therefore, preparation of inorganic membrane with nano-sized pore have been attracting more and more attention.

• Membrane and Water Treatment
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• v.2 no.4
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• pp.207-223
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• 2011

Supported Liquid Membranes (SLMs) have been widely studied as feasible alternative to traditional processes for separation and purification of various chemicals both from aqueous and organic matrices. This technique offers various advantages like active transport, possibility to use expensive extractants, high selectivity, low energy requirements and minimization of chemical additives. SLMs are not yet used at large scale in industrial applications, because of the low stability. In the present paper, after a brief overview of the state of the art of SLM technology the facilitated transport mechanisms of SLM based separation is described, also introducing the small and the big carrousel models, which are employed for transport modeling. The main operating parameters (selectivity, flux and permeability) are introduced. The problems related to system stabilization are also discussed, giving particular attention to the influence of membrane materials (solid membrane support and organic liquid membrane (LM) phase). Various approaches proposed in literature to enhance SLM stability are also reviewed. Modification of the solid membrane support, creating an additional layer on membrane surface, which acts as a barrier to LM phase loss, increases system stability, but the membrane permeability, and then the flux, decrease. Stagnant Sandwich Liquid Membrane (SSwLM), an implementation of the SLM system, results in both high flux and stability compared to SLM. Finally, possible large scale applications of SLMs are also reviewed, evidencing that if the LM separation process is opportunely carried out (no production of byproducts), it can be considered as a green process.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.105-113
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• 2018

Maillard reaction products like melanoidins present in industrial fermentation wastewaters are complex compounds with various functional properties. In this work, novel ultrafiltration (UF) mixed matrix membrane (MMM) composed of polysulfone (PSF) and nanocomposites was prepared through a phase inversion process for the recovery of melanoidins. Nanocomposites were prepared with acid functionalized multiwalled carbon nanotubes (MWCNTs) as the reinforcing filler for chitosan-thermoplastic starch blend. Higher nanocomposites content in the PSF matrix reduced the membrane permeability and melanoidins retention indicating tighter membrane with surface defects. The membrane surface defects could be sealed with dilute polyvinyl alcohol (PVA) solution. The best performing membrane (1% nanocomposites in 18% PSF membrane sealed with 0.25% PVA coating) resulted in uniform melanoidins retention of 98% and permeability of 3.6 L/m2 h bar over a period of 8h. This demonstrates a low fouling PSF membrane for high melanoidins recovery.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.500-505
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• 2004

The present study was to investigate the purification of a fermentation broth by an electromicrofiltration membrane. Microfiltration runs with a crude and a centrifuged broth, with solution of particles recovered from centrifugation and with permeates from microfiltration experiments were thus compared. Microfiltration performances were governed by colloids and small particles that induced sharp initial flux declines. For these results, the evolution of the overall membrane resistance was increased by $80\%$ in comparison with the electromicrofiltration membrane. The main focus of this study was set on the enhancement of the filtrate flux by an electric field. This pressure electrofiltration leads to a drastic improvement of the filtration by $100\%$ and the filtration time was thereby reduced. Pressure electrofiltration serves as an inter­esting alternative to the cross-flow filtration and it effectively separates advantageous constitu­ents such as amino acids and biopolymers from a fermentation broth. They were equally main­tained during the microelectrofiltration, although they were significantly reduced by $45\%$ by the microfiltration without the application of an electric field. Accordingly, since the electrofiltration membrane was provided more permeability, this study experimentally demonstrates that the permeability inside a membrane can be controlled using an electric field.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.1
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• pp.133-137
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• 2006

Ion permeability characteristics in nano-polymer membrane structures are performed to investigate the chemical composition and characteristics of MEA(Membrane Electrolyte Assembly) which is one of the most important parts to decide the performance in PEMFC(Polymer Electrolyte Membrane Fuel Cell) system. Subsequently, the MEA manufacturing process is presented for the uniformed MEA product. In the meantime, the analysis of SEM(Scanning Electron Microscope) is carried out in order to investigate the joint aspect and chemical composition of MEA. As a result of SEM analysis, it is found that the bonded catalyst and carbon composition contain the reasonable amount to get unit cell output. It is also found that the humidification gives the better performance result slightly.

• Textile Coloration and Finishing
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• v.6 no.4
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• pp.72-76
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• 1994

The permselectivity of alkali metal chlorides through silk fibroin membrane was investigated at $25^{\circ}C$: The Permeability coefficients were found to increase in a sequence of LiCl < NaCl < KCl < CsCl. This sequence was explained by considering the partition and the hydrophilic membrane. The dependence of the permeability on the salts concentration was interpreted by means of TMS theory. The ionic mobility ratio of alkali metal chlorides through this membrane decreased with the increase of the Stokes radius. The Effectiveness of the charged density was found to depend on the ionic species. The greater the Stokes radius the larger the effective charge density of membrane.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.1
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• pp.51-58
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• 2006

The promoting effect of hydrogen peroxide ($H_2O_2$) against the cytotoxicity of 1-methyl-4-phenylpyridinium ($MPP^+$) in differentiated PC12 cells was assessed by measuring the effect on the mitochondrial membrane permeability. Treatment of PC12 cells with $MPP^+$ resulted in the nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species (ROS) and depletion of GSH. Addition of $H_2O_2$ enhanced the $MPP^+-induced$ nuclear damage and cell death. Catalase, Carboxy-PTIO, Mn-TBAP, N-acetylcysteine, cyclosporin A and trifluoperazine inhibited the cytotoxic effect of $MPP^+$ in the presence of $H_2O_2$. Addition of $H_2O_2$ promoted the change in the mitochondrial membrane permeability, ROS formation and decrease in GSH contents due to $MPP^+$ in PC12 cells. The results show that the $H_2O_2$ treatment promotes the cytotoxicity of $MPP^+$ against PC12 cells. $H_2O_2$ may enhance the $MPP^+$-induced viability loss in PC12 cells by promoting the mitochondrial membrane permeability change, release of cytochrome c and subsequent activation of caspase-3, which is associated with the increased formation of ROS and depletion of GSH. The findings suggest that $H_2O_2$ as a promoting agent for the formation of mitochondrial permeability transition may enhance the neuronal cell injury caused by neurotoxins.

• Membrane Journal
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• v.25 no.3
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• pp.248-255
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• 2015

Aminated polyetherimide membrane synthesized in the laboratory according to amine ratio was used for measurement of gas permeability, diffusivity, and solubility about carbon dioxide, nitrogen, methane, oxygen, and sulfur dioxide with Time-lag method at room temperature. Generally, gas permeability is totally decreased because the more amination rate reacted to the main chain of amine groups, the more intermolecular space became narrow. However, gas permeability of sulfur dioxide was increased due to combination of sulfur dioxide and amine groups have acid and base properties respectively. Diffusivity and solubility of dry gas are totally decreased excluding sulfur dioxide as increasing amination rate. In case of sulfur dioxide, however, diffusivity as well as solubility was increased as increasing amination rate. Selectivity of carbon dioxide/nitrogen showed 60 when amination rate was 3. In case of humid gas, gas permeability of carbon dioxide was 70 barrer when relative humidity showed 100, and selectivity with nitrogen approximately showed 18.

• Membrane Journal
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• v.13 no.1
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• pp.47-53
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• 2003

Poly(ether ether ketone)(PEEK) was sulfonated using sulfuric acid and blended with polysulfone with various ratios. The blended polymer electrolyte membranes were characterized in terms of methanol permeability, proton conductivity and ion exchange capacity. As the amount of sulfonated PEEK increased, both methanol permeability and proton conductivity increased. This was due to the increase of ion exchange capacity. The experimental results indicated that the blend membrane with 20% polysulfone was the best choice In terms of the ratio of proton conductivity to methanol permeability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.645-648
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• 2005

The grounds of multipurpose practical use degree are built much holding world cup 2002 but material that is used in this building most external membrane ceiling is accomplishing PTEE A master and servant. Therefore, this research analyzed assessment about sound absorption special quality that measure ventilation quantitys of 10 act material and analyze correlation with Air Permeability and the sound absorption rate, and follow in change of layer of air of inside facts material. Result is as following. When Air Permeability good dimension is 5$\sim$15 cc/cm$^2$/sec and acoustic absorptivity is the best as Air Permeability result that measure acoustic absorptivity of inside facts material particularly firstly, could know 8$\sim$9 cc/cm$^2$/sec love. When establish sound absorption inside facts in external membrane as result that measure acoustic absorptivity of inside (acts material secondly, could know that acoustic absorptivity is good though become about minimum back layer of air 900mm.