• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.458-464
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• 1999

The value of lysozyme as a natural food preservative is continuously increased due to its unique antimicrobial activity. To determine the optimum separation concentration among the various hen egg white protein (HEWP) concentrations (0.25, 0.5, 1.0, w/v), protein concentrations, lysozyme concentrations, specific activities (SA), and purification factors of prefiltered solution (PFS) and PM30 permeate solution (PMS) were compared. The purity of lysozyme separated at each step was analyzed and confirmed by gel permeation chromatography and electrophoresis. The fouling deposits on membrane were observed by SEM. The non-enzymatic proteins were removed over 99% by ultrafiltration (UF). The increased feed concentration did not contribute to the increase of SA. SA of PMS was 18 to 31 times higher than that of PFS. The optimum feed concentration was decided as 0.25% based on SA and purification factor. The non-enzymatic region of gel chromatogram was proved to be ovalbumin. The thickness of deposit on the UF membrane was approximately $0.9{\mu}m$ and removed by cleaning with 0.1 N NaOH. Therefore, UF using PM30 membrane was very effective to separate the antimicrobial lysozyme from various HEWPs.

• Membrane Journal
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• v.28 no.5
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• pp.340-350
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• 2018

In the present study, crystallographically b- and c-axis oriented mordenite zeolite membranes were prepared and their pervaporative ethanol dehydration was investigated. The seed layer with a high coverage grew to be c-axis oriented dense layer, while the seed layer with a low coverage grew to be b-axis oriented layer. This phenomenon could be explained by the evolutionary selection growth mechanism. The b-axis grown membrane with 8-membered rings showed a high separation factor of above 1000 and a considerable total flux of around $0.2kg/m^2h$. The c-axis grown, columnar structured membrane with 8- and 12-membered rings showed a low separation factor of less than 200 and a relatively high total flux of around $0.25kg/m^2h$. The high performance of b-axis grown membrane was due to the relatively small opening of 8-membered rings. Water molecules can freely permeate through the openings, but ethanol molecules, difficultly. Therefore, in the present study, we introduced a new method to control crystallographic orientation of mordenite membrane by changing seeding amount of needle-like crystals, and elucidated that b-axis oriented mordenite membrane showed better performance than c-axis grown mordenite membrane.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.337-344
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• 2006

Characteristics of flocculent aggregates have great effects on membrane fouling. Floc from kaolin particles gave higher permeate throughputs than floc from natural particles at the same conditions. Therefore, the objectives of this study are to thoroughly analyze characteristics of flocculated aggregates and to investigate effects of flocculated aggregates on membrane fouling. Image analysis, specific rake resistance and cake compressibility were used for characterization of flocs. Different flocculent aggregates formed with natural and kaolin particles were employed in this study. The fractal dimensions from the image analysis were $D_2=1.79{\pm}0.07$ for floc from natural particles and $D_2=1.84{\pm}0.06$ for floc from kaolin particles. The lower fractal dimension($D_2$) of floc from natural particles indicated that the aggregates were more porous and less compact than floe from kaolin particles. In addition, both the specific cake resistances and compressible degrees of flocs from natural particles showed greater values than those of flocs from kaolin particles. The results implied that the porous and loose flocs from natural particles were more easily compressed on membrane surface than the dense and compact flocs from kaolin particles. The compressed flocs yielded the great hydraulic resistances by hindering the water flow through the cake layer.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.417-426
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• 1997

Rice bran protein hydrolysates were prepared and some of their physicochemical properties were investigated to utilize rice bran as starting material for functional food ingredient. Rice bran proteins (RBP) were prepared from defatted rice bran by alkaline extraction and isoelectric precipitation. The enzyme for hydrolysis of RBP was selected through measuring relative activity by pH-drop method and comparing the degree of hydrolysis (DH) of hydrolysates. The enzymatic hydrolysates prepared by $Esperase^{\circledR}$ treatment were partitioned into two fractions by ultrafiltration(UF) with a 10 kDa molecular weight cut-off membrane. Each fraction was applied to a cholic acid-conjugated ${\omega}-aminohexyl$ Sepharose 4B column and the bile acid-binding components were obtained by eluting with deoxycholate. Gel permeation chromatography on a Sephadex G-50 column revealed that molecular weight of the bile acid-binding fraction of UF permeate was distributed in ranges of $2\;kDa{\sim}10\;kDa$ and $0.2\;kDa{\sim}0.6\;kDa$. Three peaks (R-1, R-2 and R-3) were obtained by prep-HPLC of bile acid-binding fraction of UF retentate and analyzed for total and free amino acid composition. The results showed that proline content of the bile-acid binding polypeptides and peptides was four times as much as that of rice bran protein and that the peak corresponding to higher average hydrophobicity had a higher free amino acid content. Average hydrophobicity slightly increased with enzymatic hydrolysis.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.295-301
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• 2015

A theoretical analysis was carried out to examine the concentration behavior of methane from a biogas using a polysulfone membrane. After the governing equations were derived for the cocurrent flow mode in a membrane module, the coupled nonlinear differential equations were numerically solved with the Compaq Visual Fortran 6.6 software. At the typical operating condition of mole fraction of 0.7 in a feed stream, the mole fraction of methane in the retentate increased to 0.76 while the normalized retentate flow rate to the feed flow rate decreased from 1 to 0.79. When either the mole fraction of methane in a feed increased or the pressure of the feed stream increased, the methane mole fraction in the retentate increased. On the other hand, it was found that as either the membrane area decreased or the ratio of the permeate pressure to the feed pressure increased, the methane mole fraction in the retentate decreased. In case that the stage cut increased, the methane mole fraction in the retentate increased while the recovery of methane slightly decreased.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.43 no.3
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• pp.189-194
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• 2017

Skin has a strong barrier function to protect the body from external harmful factors. This strong barrier function of the skin makes for any effective substance difficult to permeate through the skin. The purpose of this study was to evaluate skin permeability of the reduced particle size by non-invasive method. The particles were prepared by high-pressure emulsification. The niacinamide prepared in a high-pressure emulsification was absorbed 1.56 times higher than the control sample. In addition, it was found from the sixth layer of keratin that was removed by tape-stripping method. This was significantly deeper penetration. The whitening efficacy of the sample containing niacinamide was evaluated before and after 6 weeks of use. The skin color was significantly improved in both pigmented area and non-pigmented area. Through this study, it was possible to visually and quantitatively confirm the permeability confirm the permeability of the reduced particle sample into skin.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.115-120
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• 2010

The formidable barrier property of the stratum cornemum and the high hydrophilicity of active ingredient make it difficult to permeate through the skin and reach to its site of action. The aim of this study was to investigate the effect of chemical penetration enhancers on the skin permeation of a hydrophilic cosmetic active ingredient, such as arbutin. The enhancing effects of N-methyl-2-pyrrolidone (NMP) on the permeation of a hydrophilic cosmetic active ingredient were evaluated by using Franz diffusion cell. The study indicated that NMP has considerable influence on the skin permeability. NMP was not only the most effective enhancer but also increased the skin permeability of arbutin approximately 1.3~1.5 fold compared with control without penetration enhancer. The lag time did not change with NMP, which suggested no effect of NMP on skin lipid fluidity. This suggest that arbutin co-permeated with NMP. The results indicate NMP is effective enhancer of a hydrophilic cosmetic active ingredient in penetration, with potential applications for drug delivery system.

• Membrane Journal
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• v.15 no.4
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• pp.297-309
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• 2005

As a number of potential endocrine disrupting compounds (EDCs) are released into the environment, recently growing attention has been drawn to them. Therefore sensitive and reliable analytical methods are essential to monitor those compounds. In this study, complementary CC-MS and LC-MS were employed to analyze the endocrine disrupters, and the results of two methods were compared for di(2-ethylhexyl)phthalate (DEHP), benzylbutylphthalate (BBP), pentachlorophenol (PCP), and 4,4'-Isopropylidenediphenol (Bisphenol-A, or BPA). The results indicate that it was possible to lower the detection limits of EDCs by LC-MS. Also, LC-MS enabled to identify the EDCs as almost intact molecules. Furthermore, this study presented a nanofiltration membrane (MWCO 250) and a ultrafiltration membrane (MWCO 1,000) filtration system as methods far removing EDCs from drinking water containing $\gamma$-BHC, p,p'-DDE, BBP, p,p'-DDT, DEHP, PCP, and BPA. Cross-flow type nanofiltrations showed $100\%$ removal of EDCs, and the result implies that MWCO 250 nanofilter was sufficient for treatment of EDCs. The ratio of permeate flux to mass transfer coefficient of nanofiltration, high flux ultrafiltration, and low flux ultrafiltration with ultrapure water were 0.67, 3.4, and 0.44, respectively. It was found that nanofiltration and low flux ultrafiltration were operated at a diffusion dominant condition, and the high flux ultrafiltration was operated at a convection dominant condition. Furthermore, a diffusion dominant process attained reasonable rejection of EDCs. The removal in the ultrafiltration was depending on the molecular weight of an EDC, and the filtration was governed by diffusion-dominant hydrodynamic conditions.

• Membrane Journal
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• v.15 no.4
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• pp.310-319
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• 2005

This paper describes the preliminary study on the development of multi-stage membrane demonstration plant for removal of carbon dioxide from flue gas stream being emitted from LNG boiler in thermal power generation plant. The prerequisite requirement is to design and develop the membrane process producing a $99\%\;CO_2$ with $90\%$ recovery from LNG flue gas of 1,000 $Nm^3$/day. Asymmetric polyethersulfone hollow fiber membranes and membrane modules developed in this laboratory[1] were used in this study. Using the permeation data for the hollow fiber membranes, modelling on the membrane module and multi-stage membrane process was done to meet the requirement condition of the process design. The effects of the operating pressure of feed and permeate side and feed concentration on $CO_2$ purity and recovery were investigated experimentally with the developed hollow fiber modules. These experimental results matched well with theoretical modelling results.

• Membrane Journal
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• v.4 no.4
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• pp.221-231
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• 1994

The GR51PP(MWCO 50,000) and GR40PP(MWCO 100,000) membranes manufactured by DDS were used in ultrafiltration of dextran(Mw. : 500,000) solution in flat plate ultrafiltration cell filled with various types of turbulence promoters. The flux improvement by using turbulence promoter was higher in laminar flow region than in turbulent flow region. The maximum improvements of permeate flux were foud as 112% and 50% I laminar flow region and turbulent flow region, respectively. Also, the solute rejection of the ultrafiltration membrane was improved by turbulence promoters and its effect was significant in the high transmembrane pressure and laminar flow region. The smaller the spacer mesh size was used, the higher the flux improved, but the pressure drop in ultrafiltration cell also increased. In laminar flow region, pressure drop by the spacer was negligible, but in turbulent flow region it changed significantly depending upon the mesh size of the spacer and therefore, its mesh size must be baken into account in the design of the process. The predicted results of the modified mass transfer correlation had better agreement with experimental results than those of unmodified one, The modified mass transfer correlations for laminar and turbulent flow region are shown as follow. $N_{sh}=0.151(N_{Re})^{0.199}(N_{Sc})^{0.22}(N_{Scm})^{0.197}\;(625 $N_{sh}=0.0165(N_{Re})^{0.428}(N_{Sc})^{0.33}(N_{Scm})^{0.223}\;(5015