• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.33-36
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• 2001

In this paper, we have studied the characteristics of wet etching using citric acid based wet etchant. We have used the citric acid / hydrogen peroxide solution, citric acid / hydrogen peroxide / D.I. water solution. From our experimental result, a volumetric 1：3 ratio of citric acid and hydrogen peroxide and 1 ： 3 ： 1 ratio of citric acid, hydrogen peroxide, and D.I. water is shown to be a better wet etchant of PHEMT's system.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.133-136
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• 2000

Soil decontamination process was conducted to study adsorption and modeling characteristic of Sr$^{2+}$ ion using citric acid and water system with TRIGA soil. When the concentration of citric acid was increased, the BTC of Sr$^{2+}$ ion was to be closed to the BTC of $^3$$H_2O$ at experiments of soil adsorption. Beside, when the concentration of citric acid was under 0.01M Sr$^{2+}$ ion, BTLs was asymmetry. It was characteristic of nonequilibrium adsorption. R and $K_{p}$ , were decreased to be increased the concentration of citric acid. Asymmetry modeling was nearly the same to be compare with symmetry modeling in decontamination process, when the concentration of citric acid was decreased. Result of experiment was agree with asymmetry and symmetry model, when the concentration of citric acid was increased.eased.

• Membrane and Water Treatment
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• v.7 no.2
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• pp.143-154
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• 2016

Acetic acid can be removed from wastewater by esterification in a membrane reactor. Pervaporation membrane reactor (PVMR) is an alternative process to conventional separation processes. It is an environmentally friendly process. The main advantages of the PVMR are simultaneous water removal and production of an ester economically. In this study, the synthetic wastewater has been used. Esterification reaction of acetic acid with isopropanol has been studied in the presence of tungstosilicic acid hydrate as a catalyst in a batch reactor and in a PVMR. The effects of important operating parameters such as reaction temperature, initial molar ratio of isopropanol to acetic acid and catalyst concentration has been examined. Removal of acetic acid (conversion of acetic acid) was obtained as 85% using a PVMR by removal of water from the reaction mixture.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.73-80
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• 2024

To determinate the content of acanthoic acid and kaurenoic acid in 70% EtOH and hot water extracts of Eleutherococcus gracilistylus, quantitative analysis of each compound in samples was carried out by a HPLC-UVD. Also, the identification of each acompound in samples was successfully assigned by LC-MS analysis. In result, the contents of acanthoic acid and kaurenoic acid in 70% ethanoic extracts were 28.84±0.21 mg/g (2.88%), 26.38±1.63 mg/g (2.64%), respectively. However, the content of two compounds in hot-water extracts was not observed. In conclusion, it shows that 70% ethanol as a best extraction solvent to extract the acanthoic acid and its metabolite from Eleutherococcus gracilistylus was better than hot-water solvent. The 70% ethanol complex extract of Allium Hookeri and Eleutherococcus gracilistylus showed better effectiveness. In addition, the 70% ethanol extract complex of Allium Hookeri and Eleutherococcus gracilistylus showed better effects than the hot water solvent of DPPH radical scavenging ability, total polyphenols, and flavonoids content. The anti-inflammatory activity were significantly or partially reduced by treatment with ethanol extract complex(SEC) by Allium Hookeri and Eleutherococcus gracilistylus.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.3
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• pp.293-301
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• 2006

This study was undertaken to prolonging the freshness in Squid(Todarodes pacificus) on the effects of ice storage methods(tap water ice, electrolytic water ice) using stainless diaphragm electrolytic instrument and also test an efficiency of instrument. Basically, stainless diaphragm electrolytic instrument studied for changes of pH on difference water flow and ampere. The lower water flower and higher ampere made low pH on acid part of electrolytic instrument. Squid samples were stored in tap water ice, acid part of electrolytic water and base part of electrolytic water and used in studying the changes of VBN and skin color through storage. Acid water had strong sterilization effects and VBN was lower levels of acid water than the others. Base water had not sterilization effects. Tap water ice storage was more sterilizing effects than base water ice storage but less effects than acid water ice storage. Lightness of Squid skin showed getting decrease at storage of ice water of all storage methods but acid water ice storage showed more retarding than the other two storage. From these results, it could be suggested that acid electric water ice storage is effective in extendance the shelf-life of squid at chilled storage.

• Journal of the Korean Applied Science and Technology
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• v.5 no.2
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• pp.9-15
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• 1988

In order to investigate the amino acid and fatty acid content in Thuja biotae water extract treated with alkaline, it was performed. There are 16 kinds of different amino acid and 20 kinds of different fatty acid in Thuja biotae water extract. An aspartic acid was contained 52％ and proline was contained 10％, particulary, r-aminobutyric acid was analysed. Essential fatty acids; linoleic acid, linolenic acid and arachidonic acid were cotained a lot amount. There are 11 different unknown materials which were identified by GC-MS spectrum, such as N-[($4{\alpha},5{\alpha}$)-cholestan-4-yl]-acetamide; 22,26-Epithio-furost-5-en-3-ol; 2-Methyl-6-(4-methyl-3-cyclohexen-1-yl)-4-heptanone; 3,12,14-Tris(acetyloxy)-pregnane-15,20-dione;22-Methyl-26-thio-furost-5-en-3-ol; 7-Ethenyl-1,2,3,4,4a,4b,5,6,7,9,10,10a-dodecahydro-1,4a,7-trimethyl-1-phenanthrene carboxyaldehyde; Methoxyiminopro-panedioic acid; 13-Methyl-13-${\beta}$-Methyl-13-vinyl-dodecaarp-7-en-3-3-ol; 22-Methyl-26-thio-furost-6-methyl-3-ol; $5{\alpha}-Androstane-2$,11-dione; 9-Methyl-heptadecanoic acid.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.569-574
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• 2005

In this study, alginic acid that had an high affinity for a heavy metal and was noted for biological adsorbent was modified by an oxidizer, $KMnO_4$. Chemical modification changed hydroxyl of the alginic acid into carboxyl and compare with alginic acid, modified alginic acid exhibited a characteristics that carboxyl groups are comparatively high. For the use of them as an adsorbent, beads were prepared by dropping alginic acid and modified alginic acid solution in dilute 2 wt% $CaCl_2$ solution for non water soluble. The amount of removed $Cu^{2+}$ and $Pb^{2+}$ by modified alginic acid beads showed 84.7 mg and 90.9 mg per gram of beads, respectively. And it showed the amount of adsorbed heavy metal ions 10~20% higher than that of alginic acid beads in range of pH 4~7. In particular, modified alginic acid have a good adsorption capacity for $Cu^{2+}$ and $Pb^{2+}$ by Freundlich adsorption isotherm. According to this study, it is verified that alginic acid that is a nature high molecular substance improved capacity for actual application by increased heavy metal adsorption capacity by chemical modification.

• Membrane and Water Treatment
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• v.13 no.4
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• pp.201-208
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• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.3
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• pp.425-425
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• 1995

The interaction and detergency between liquid oily soil and surfactant solution were studied by the mechanism of formation of liquid crestal(LC). Samples used were triolein as a triglyceride, oleic acid as a free fatty acid and sodium dodgily sulfate (SDS) as a surfactant. The results were as follows: In the phase diagram of SDS/oil/Water system, the area of liquid crystalline phase region were in the order of SDS/trillion/water< SDS/oleic acid/water< SDS/mixture of trillion and oleic acid/water. In the system of oleic acid alone or mixture of trillion and oleic acid contacted with SDS solution, the LC phase was formed right after or after some time with SDS concentration. But in a case of trillion alone, the LC phase was not formed although the concentration of the SDS solution was relatively high. The detergency of model oily soils were seldom changed with temperature, and the detergency of oleic acid was very high compared to that of the trillion. The detergency of mixed soil was improved with the increase of the ratio of oleic acid in the mixture.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.3
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• pp.426-433
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• 1995

The interaction and detergency between liquid oily soil and surfactant solution were studied by the mechanism of formation of liquid crestal(LC). Samples used were triolein as a triglyceride, oleic acid as a free fatty acid and sodium dodgily sulfate (SDS) as a surfactant. The results were as follows: In the phase diagram of SDS/oil/Water system, the area of liquid crystalline phase region were in the order of SDS/trillion/water< SDS/oleic acid/water< SDS/mixture of trillion and oleic acid/water. In the system of oleic acid alone or mixture of trillion and oleic acid contacted with SDS solution, the LC phase was formed right after or after some time with SDS concentration. But in a case of trillion alone, the LC phase was not formed although the concentration of the SDS solution was relatively high. The detergency of model oily soils were seldom changed with temperature, and the detergency of oleic acid was very high compared to that of the trillion. The detergency of mixed soil was improved with the increase of the ratio of oleic acid in the mixture.