• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.959-970
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• 2000

A laboratory-scale experiment was conducted to investigate the effect of soluble microbial products(SMP) on permeate flux in the submerged membrane separation activated sludge process. Continuous and batch filtration test were operated to understand mechanism of relationship between membrane fouling and SMP. Synthetic wastewater(phenol) was used as a carbon source. Hydraulic retention time(HRT) and mixed-liquor volatile suspended solids(MLVSS) of the reactor were kept at 12 hours and 9.000mg VSS/L, respectively. Batch filtration tests ($J_{60}/J_o$) using the mixed liquor from reactor showed that the increase of accumulated SMP concentration in the reactor caused to the decreasing permeate flux and the increasing of the adhesion matters which form cake and gel layer. The resistance value of cake layer was measured $2.9{\times}10^{10}{\sim}4.0{\times}10^{10}(1/m)$, this value showed more significant effect on flux drop than that of among other resistance layers. Batch phenol-degradation experiment was conducted to observe SMP type expected $SMP_{nd}$ and $SMP_{e}$ (SMP resulted from endogenous cell decomposition), these are non-biodegradable high molecular weight organic matter and playa significant role in permeate flux drop. Also, SMP concentration was accumulated as increased of HRT against flux drop.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.420-426
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• 2017

Recently, solvent-resistant nanofiltration membranes have been studied for the separation of solvents or solutes using a molecular weight cut-off system of the polymer which is resistant to a specific solvent. Required conditions for these membranes must have are excellent physical properties and solvent resistance. Polybenzimidazole, which is known to be one of the most heat-resistant commercially available polymers, has an excellent inherent solvent resistance and it is even insoluble in stronger organic solvents when cross-linked. Therefore, in this study, the applicability of polybenzimidazole as a solvent resistant nanofiltration membrane was discussed. The membrane was fabricated using the non-solvent induced phase separation method and showed a suitable morphology as a nanofiltration membrane confirmed by field emission scanning electron microscopy. In addition, the permeance of the solvent in the presence or absence of cross-linking was investigated and the stability was also confirmed through long operation. The permeance test was carried out with five different solvents: water, ethanol, benzene, N, N-dimethylacetamide (DMAc) and n-methyl-2-pyrrolidone (NMP); each of the initial flux was $6500L/m^2h$ (water, 2 bar), $720L/m^2h$ (DMAc, 5 bar), $185L/m^2h$ (benzene, 5 bar), $132L/m^2h$ (NMP, 5 bar), $65L/m^2h$ (ethanol, 5 bar) and the pressure between 2 and 5 bar was applied depending on the type of membrane.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.302-308
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• 1997

${\beta}-Cyclodextrin\;({\beta}-CD)$ polymers were prepared using epichlorohydrin as a cross linking agent. The polymers were separated into ${\beta}-CD$ soluble polymer $({\beta}-CD\;SP)$ and ${\beta}-CD$ insoluble polymer $({\beta}-CD\;ISP)$ on a 10,000 molecular weight cut-off membrane (YM 10). Optimum separation conditions in the YM 10 were: transmembrane pressure 51.7 kPa, separation temperature $35^{\circ}C$, and volume concentration ratio 10. The flux was $0.025\;mL/cm^{2}/min$ under the optimum conditions. Gel permeation chromatography indicated that ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$ had a degree of polymerization of $2{\sim}8$ and over 10, respectively. The formation of an inclusion complex with hydrophobic compounds such as 4-dimethylaminoazobenzene, methyl red, and naringin was compared among ${\beta}-CD,\;{\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. The molar absorptivity for the two chromatic compounds was increased and the absorption peak was shifted in the presence of ${\beta}-CD$ polymers. Naringin, the principal flavonoid bitter tasting component of citrus fruit, had a low water solubility. The solubility of naringin was increased through the formation of an inclusion complex with ${\beta}-CD$ polymers. There was no significant difference in the formation of an inclusion complex between ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. Reduction of the bitter components from citrus products was shown to be possible when employing ${\beta}-CD\;SP$, while the usage of ${\beta}-CD$ monomer has been limited due to the low water solubility.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.359-364
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• 2014

In this study, we developed a HPLC method for the separation and analysis of methylparaben and p-anisic acid, which are commonly used as a synthetic preservative and natural preservative, respectively. Methylparaben and p-anisic acid have same molecular weight (152.15 g/mol), similar structure and same maximum absorption wavelength (250 nm), thus they showed same retention time (RT) value (13.3 min) in HPLC experiment. We observed that two substances are separated on C18 column after methylparaben was derivatized selectively through the acetylation reaction. Instead, RT of the acetylated methylparaben was moved to 23.9 min from 13.3 min. The average retention time was $23.9{\pm}0.1min$ and peak area values was $5042882{\pm}4778$. In addition it showed a high linearity in the calibration curve with a correlation coefficient (R2) of 0.9999658. Detection and quantitation limits were $1.47{\mu}g/mL$ and $4.44{\mu}g/mL$, respectively. In conclusion, the developed method can be useful for separation and analysis of preservatives with similar structure in cosmetic fields.

• Journal of the Korean Society of Tobacco Science
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• v.2 no.1
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• pp.1-7
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• 1980

Gel filtration column chromatography (Sephadex G-75), dialysis an d Brushite column chromatography were carried out to separate the brown pigmented macromolecule from water extracts of the cured leaf tobaccos. The two distinct macromolecules having different molecular weight were separated by the Sephadex column chromatography. Brushite also separated two different species of macromolecules which might have different electronic structures. According to the enzymatic degradation of protein in Burley and Hicks, chymotrypsin showed the best degradation ratio, ie., 16-30% in Burley and 38-57% in Hicks. Similar effect was observed with pepsin. However, very low effect of degradation was revealed with trypsin. The sample treated with the proteolytic enzymes revealed the disappearance of the first peak and the slight decrease of the 2nd peak height in the separation profile of Sephadex. After dialysis, the brown pigmented macromolecule was pyrolyzed at $300^{\circ}C$ and the strongly fluorescent components not identified before pyrolysis were detected with TLC separation. Absorption spectrum of these fluorescent compounds was monitored in benzene and the absorption maxima at 265nm and 275 nm were obtained. Considering absorption maxima and shape of the spectrum, those fluorescent compounds seem to be PAH derivatives.

• Development and Reproduction
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• v.7 no.2
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• pp.105-112
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• 2003

Previously, we discovered a new MMP-2 isoform GA110, of which appearance in human follicular fluid(FF) and serum was increased by EDTA. The present study was conducted to investigate how GAI 10 can appear by EDTA. To examine possible involvement of protein disulfide isomerase(PDI), an enzyme responsible for the dimerization of protein via disulfide formation, effect of PDI inhibitor on the appearance of GA110 by EDTA was investigated. When PDI inhibitor added to FF before EDTA treatment, the gelatinolytic activity of GA110 was abolished in a concentration dependent manner. By contrast, the activity of 72 kDa gelatinase increased. However, the PDI inhibitor added to FF after EDTA treatment, the gelatinolytic activity of GA110 was unaffected. To find out the nature of the enzyme which converts 72 kDa gelatinase into GAI 10, chromatographic separation method of FF proteins was done. Using hydroxyapatite column, fractions rich in 72 kDa gelatinase were isolated and pooled. By using this pool as substrate for the 72 kDa converting enzyme, protein fractions containing the converting activity were obtained from chromatographic separation of FF onto glutathione sepharose fast flow column. When immunoblotting was performed on this enzymatically active protein fractions against polyclonal anti-PDI antibody, distinct immunoreactivity was observed, although appeared in smaller molecular weight region. Based on these observations, it is suggested that the appearance of GAI 10 in FF by EDTA treatment could be due to an activation of PDI-like enzyme, which dimerizes 72 kDa gelatinase into GAI 10 via the formation of disulfide bond between molecules.

• Membrane Journal
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• v.27 no.2
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• pp.167-181
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• 2017

Graphene-based materials have been considered as a promising membrane material, due to its easy processability and atomic thickness. In this study, we studied on gas permeation behavior in few-layered GO membranes prepared by spin-coating method. The GO membrane structures were varied by using different GO flake sizes and GO solutions at various pH levels. The GO membranes prepared small flake size show more permeable and selective gas separation properties than large one due to shortening tortuosity. Also gas transport behaviors of the GO membranes are sensitive to slit width for gas diffusion because the pore size of GO membranes ranged from molecular sieving to Knudsen diffusion area. In particular, due to the narrow pore size of GO membranes and highly $CO_2$-philic properties of GO nanosheets, few-layered GO membranes exhibit ultrafast and $CO_2$ selective character in comparison with other gas molecules, which lead to outstanding $CO_2$ capture properties such as $CO_2/H_2$, $CO_2/CH_4$, and $CO_2/N_2$. This unusual gas transport through multi-layered GO nanosheets can explain a unique transport mechanism followed by an adsorption-facilitated diffusion behavior (i.e., surface diffusion mechanism). These findings provide the great insights for designing $CO_2$-selective membrane materials and the practical guidelines for gas transports through slit-like pores and lamellar structures.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.938-943
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• 2017

Objective: Qingyu pig, a Chinese indigenous pig breed, exhibits two types of coat colour phenotypes, including pure black and white with black spotting respectively. Melanocortin receptor 1 (MC1R) and agouti signaling protein (ASIP) are two widely reported pivotal genes that significantly affect the regulation of coat colour. The objectives of this study were to investigate whether the polymorphisms of these two genes are associated with coat colour and analyze the molecular mechanism of the coat colour separation in Qingyu pig. Methods: We studied the phenotype segregation and used polymerase chain reaction amplification and Sanger sequencing to investigate the polymorphism of MC1R and ASIP in 121 Qingyu pigs, consisting of 115 black and 6 white with black spotted pigs. Results: Coat colour of Qingyu pig is associated with the polymorphisms of MC1R but not ASIP. We only found 2 haplotypes, $E^{QY}$ and $E^{qy}$, based on the 13 observed mutations from MC1R gene. Among which, $E^{qy}$ presented a recessive inheritance mode in black spotted Qingyu pigs. Further analysis revealed a g.462-463CC insertion that caused a frameshift mutation and a premature stop codon, thus changed the first transmembrane domain completely and lost the remaining six transmembrane domains. Altogether, our results strongly support that the variety of Qingyu pig's coat colour is related to MC1R. Conclusion: Our findings indicated that black coat colour in Qingyu pig was dominant to white with black spotted phenotype and MC1R gene polymorphism was associated with coat colour separation in Qingyu pig.

• Membrane Journal
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• v.27 no.1
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• pp.1-42
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• 2017

Metal-organic frameworks (MOFs) are nanoporous materials that consist of organic and inorganic moieties, with well-defined crystalline lattices and pore structures. With a judicious choice of organic linkers present in the MOFs with different sizes and chemical groups, MOFs exhibit a wide variety of pore sizes and chemical/physical properties. This makes MOFs extremely attractive as novel membrane materials for gas separation applications. However, the synthesis of high-quality MOF thin films and membranes is quite challenging due to difficulties in controlling the heterogeneous nucleation/growth and achieving strong attachment of films on porous supports. Microwave-based synthesis technology has made tremendous progress in the last two decades and has been utilized to overcome some of these challenges associated with MOF membrane fabrication. The advantages of microwaves as opposed to conventional synthesis techniques for MOFs include shorter synthesis times, ability to achieve unique and complex structures and crystal size reductions. Here, we review the recent progress on the synthesis of MOF thin films and membranes with an emphasis on how microwaves have been utilized in the synthesis, improved properties achieved and gas separation performance of these films and membranes.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.816-822
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• 2011

Pervaporation is known to be a low energy consumption process since it needs only an electric power to maintain the permeate side in vacuum. Also, the pervaporation is an environmentally clean technology because it does not use the third material such as an entrainer for either an azeotropic distillation or an extractive distillation. In this study, Silicalite-1 particles are hydrothermally synthesized and polydimethylsiloxane(PDMS)-zeolite composite membranes are prepared with a mixture of synthesized Silicalite-1 particles and PDMS-polymer. They are used to separate n-butanol from its aqueous solution. Pervaporation characteristics such as a permeation flux and a separation factor are investigated as a function of the feed concentration and the weight % of Silicalite-1 particles in the membrane. A 1,000 $cm^3$ aqueous solution containing butanol of low mole fraction such as order of 0.001 was used as a feed to the membrane cell while the pressure of the permeation side was kept about 0.2~0.3 torr. When the butanol concentration in the feed solution was 0.015 mole fraction, the flux of n-butanol significantly increased from 14.5 g/ $m^2$/hr to 186.3 g/$m^2$/hr as the Silicalite-1 content increased from 0 wt% to 10 wt%, indicating that the Silicalite-1 molecular sieve improved the membrane permselectivity from 4.8 to 11.8 due to its unique crystalline microporous structure and its strong hydrophobicity. Consequently, the concentration of n-butanol in the permeate substantially increased from 0.07 to 0.15 mole fraction. This composite membrane could be potentially appliable for separation of n-butanol from insitu fermentation broth where n-butanol is produced at a fairly low concentration of 0.015 mole fraction.