• Journal of architectural history
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• v.22 no.6
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• pp.59-66
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• 2013

This study progressed an investigation on the cause of the efflorescence phenomenon of bricks in Suwon Hwaseong Fortress, which is designated as a UNESCO World Heritage by using diverse scientific analyses. The samples were taken in Hwaseong and analyzed using XRD and SEM-EDS for the material identification of efflorescence. We observed under a polarizing microscope and measured absorption factors for the basic investigation for traditional bricks. As a result of material identification, soluble salt($Na_2SO_4$, $KNO_3$) and insoluble salt($CaCO_3$) were detected. There was no big difference between original bricks and repaired bricks under the polarizing microscope. However, in terms of the water absorption rate, bricks which were used for repair nowadays showed low water absorption rate(1%). In conclusion, soluble salt and insoluble salt appeared due to an effect of an air pollution and joint mortar. Soluble salt was removed in the rainy season, but insoluble salt was not removed. As a result of the efficiency and safety tests for chemicals removing efflorescence, chemical E is likely to be the suitable chemicals for the efflorescence phenomenon of traditional bricks in Suwon Hwaseong Fortress. In the future, consideration whether the use of lime is available or not should be studied through comprehensive researches including repair work, construction work and the environment factor with lime. Also, physical, chemical identifications of repairing bricks will be required.

• Journal of the Korean Society of Food Culture
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• v.18 no.6
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• pp.562-568
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• 2003

This study was performed to study the removal efficiency of residual organophosphorus pesticides with process for making Perilla Jangachi. Two organophosphorus pesticides(chlorpyrifos-methyl and fenitrothion) were artificially attached to Perilla leaves. Then Perilla leaves were washed with detergent solution for 1minute and rinsed 2 times each for 1 minutes. After washing with neutral detergent solution, Perilla Jangachi was made with 2 steps of optimal condition. As a pretreatment, when soaked with 2% salt concentration solution for 42hours, the removal rate of residual pesticides was 81.75% of chlorpyrifos-methyl and 76.82% of fenitrothion. When Perilla leaves were steamed for 72 seconds after soaking, it became 88.94% and 82.19%, respectively. Finally, after making optimal Perilla Jangachi with 27% onion contents, removal rate was 89.12% of chlorpyrifos-methyl and 82.76% of fenitrothion. Consequently, it appeared that the process for making Perilla Jangachi effectively removed the residual pesticides of Perilla leaves.

• Membrane Journal
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• v.12 no.3
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• pp.171-181
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• 2002

The parameter which determines the plateau length of current-voltage curve for ion- exchange membranes was studied at various concentrations of NaCl and different flow rates. Moreover, the feasibility of the electrodialytic removal of 0.1 M NaCl solution at various current densities was tested by assessing the electrodialysis performance parameters such as salt removal efficiency, current efficiency, energy consumption and water dissociation. The diffusion boundary layer (DBL) thickness decreased with the NaCl concentration and flow rate of fled solution and it was observed that the plateau length of current-voltage curves was related with the DBL thickness. The removal efficiency and current efficiency were not affected significantly by the current densities even at the overlimiting current region indicating that most current were passed by electrolyte, and water dissociations are not responsible for the overlimiting current. Energy consumption increased when the current density supplied exceeded the limiting current density (LCD) values, because additional energy was necessary to overcome the plateau potential. Beyond the LCD values the energy consumption required to get a certain removal efficiency was not affected by the current density applied. The result suggests that it is allowed to operate electrodialysis processes at as high as possible current density unless water-splitting does not occur.

• Membrane Journal
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• v.26 no.1
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• pp.62-69
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• 2016

In this study, sulfonated poly(ether ether ketone) (SPEEK) as cation exchange membrane and blended and crosslinked poly(vinyl amine) (PVAm) with poly(vinyl alcohol) (PVA) membrane as anion exchange membrane were used and then the performance experiments of the membrane capacitive deionization (MCDI) installed with both membranes were carried out. The newly prepared anion exchange membrane were characterized through water content, ion exchange capacity and FT-IR. The crosslinking time of 3 h to 5 h indicated that the salt removal was reduced from 81.3, 65.7% to 53.8%. The effect of PVAm contents from 40, 60, to 80% on the salt removal was shown 81.3, 75.2 and 37.7%, respectively. As a result, it was concluded that the crosslinking time and the content of PVAm had an influence on the salt removal efficiency.

• Membrane Journal
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• v.25 no.1
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• pp.60-66
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• 2015

To investigate the performance of the composite carbon electrodes which the ion exchange polymers were directly casted onto porous carbon electrode surfaces, the adsorption/desorption experiments were carried out by varying the feed concentration, feed flow rate, and desorption voltages for the NaCl solution. When the feed concentration was 100 mg/L, the increase of the adsorption time led to the increase of the salt removal due to the increase of the residence time inside the cell while the increase of the feed flow rate from 15 mL/min to 23 mL/min gave the decrease of the salt removal efficiency, 12% because of the short residence time. When the feed concentration was 200 mg/L, the salt removal was shown 10~15% low because of the incomplete desorption within the desorption intervals.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.29-37
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• 2000

Fenton’s oxidation process is one of the most commonly applied processes to the wastewater which cannot be treated by conventional biological treatment processes. However, it is necessary to minimize the cost of Fenton’s oxidation treatment by modifying the treatment processes or other means of chemical treatment. So, as a method for the chemical oxidation of biorefractory or nonbiodegradable organic pollutants, the Photo-Fenton-Reaction which utilizes iron(11)salt. $H_2O$$_2$ and UV-light simultaneously has been proprosed. Therfore, the purpose of this study is to test a removal efficiency of dye-wastewater and treatment cost with Fenton’s and Photo-Fenton’s oxidation process. The Fe(11)/$H_2O$$_2$ reagent is referred to as the fenton’s reagent. which produces hydroxy radicals by the interaction of Fe(11) with $H_2O$$_2$. In this exoeriment, the main results are as followed; 1. The Fenton oxidation was most efficient in the pH range of 3-5. The optimal condition for initial reaction pH was 3.5 for the high CO $D_{Cr}$ & TOC-removal efficiency. 2. The removal efficiency of TOC and CO $D_{Cr}$ increased up to the molar ration between ferrate and hydrogen peroxide 0.2:1, but above that ratio removal efficiency hardly increased. 3. The highest removal efficiency of TOC and CO $D_{Cr}$ were showed when the mole ration of ferrate to hydrogen peroxide was 0.2:3.4. 4. Without pretreatment process, photo-fenton oxidation which was not absorbed UV light was not different to fenton oxidation. 5. And Fenton oxidtion with pretreatment process was similar to Fenton oxidation in the absence of coagulation, the proper dosage of F $e^{2+}$: $H_2O$$_2$ was 0.2:1 for the optimal removal efficiency of TOC or CO $D_{Cr}$ .6. Also, TOC & CO $D_{Cr}$ removal efficiency in the photo-fenton oxidation with pretreatment was increased when UV light intensity enhanced.7. Optimum light intensity in the range from 0 to 1200 W/$m^2$ showed that UV-intensity with 1200W/$m^2$ was the optimum condition, when F $e_{2+}$:$H_2O$$_2$ ratio for the highest decomposition was 0.2:2.5.EX>$_2$ ratio for the highest decomposition was 0.2:2.5.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.771-778
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• 2013

Gas hydrate (GH) process is a new desalination technology, where GH is a non- stoichiometric crystalline inclusion compounds formed by water and a number of gas molecules. Seawater GH is produced in a low temperature and a high pressure condition and they are separated from the concentrated seawater. The drawback of the GH process so far is that salt contents contained in its product does not meet the fresh water quality standard. This means that the GH process is not a standalone process for seawater desalination and it needs the help of other desalting process like reverse osmosis (RO). The objective of this study is to investigate the effect of GH process on energy saving for RO process in seawater desalination. The GH product water quality data, which were obtained from a literature, were used as input data for RO process simulation. The simulation results show that the energy saving effect by the GH process is in a range of 68 % to 81 %, which increases as the salt removal efficiency of the GH process increases. Boron (B) and total dissolved solids (TDS) concentrations of the final product of the hybrid process of GH and RO were also investigated through the RO process simulation to find relavant salt rejection efficiency of the GH process. In conclusion, the salt rejection efficiency of the GH process should exceed at least 78% in order to meet the product water quality standards and to increase the energy saving effect.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.13-19
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• 2014

Permeable reactive barrier has been recognized as the one of representative methods for remediation of contaminated groundwater. Reactive barrier system containing two and more reactive materials can remove multiple contaminants such as nutritive salts and heavy metals. In this study, removal efficiency of multiple contaminants was evaluated when both zeolite and basic oxygen furnace slag were used as reactive materials. Sequential batch test which consists of two materials was performed to evaluate removal efficiency comparing the reaction order of them against nutritive slats including ammonium and phosphate and heavy metal including cadmium. As a result, zeolite-basic oxygen furnace slag sequence batch test showed the best efficiency for removal of multiple contaminants including nutritive salts and heavy metal.

• Korean Journal of Microbiology
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• v.29 no.2
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• pp.117-122
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• 1991

In order to improve the removal ability of phosphate, Spheroplast fusions were performed among auxotrophic mutants of Aeromonas hydrophila isolated from waste water, named A13 and A14, Aci37 auxotrophic mutant of Acinetobactercalcoaceticus, and auxotrophic E. coli HR262/pCE27 carring pit gene. Eight fusants obtained from this experiment showed different biochemical characteristics. When the rate of phosphate uptake among fusants (F1-F8) was investigated in Phosphate Uptake Medium (PUM), F8 strain showed the highest rate for phosphate removal, 7 times as much as control after two hours incubation. The role of cations ($Mg^{++}$ ,$Ca^{++}$ , $K^{+}$ in phosphate uptade by F8 was also investigated in PUM without each salt. $K^{+}$ seemed to be crucial. Being compared with phosphate untake rate in PUM, that in PUM without $K^{+}$ was reduced 1.5 times. Therefore, by applying F8 strain and $K^{+}$ in practical environmental system, the increased efficiency in phosphate removal can be derived.

• Journal of the Korean Electrochemical Society
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• v.17 no.1
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• pp.37-43
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• 2014

In this study, capacitive deionization (CDI) was introduced for desalination of mining water. Ion-exchange polymer coated carbon electrodes (IEE) were used in CDI to desalt mining water. The CDI performance using the IEE for desalination of mining water was carried out and then was compared with that using general carbon electrodes without ion-exchange polymer coating (GE). Moreover, to investigate the effect of the concentration of influent solutions on CDI performance, the CDI performance using the IEE for desalination of brackish water (NaCl 200 ppm) was also performed and analyzed. As a result, the higher salt removal efficiency, rate and the lower energy consumption in the CDI process using the IEE and mining water were obtained compared with those using the GE and mining water. It is mainly due to higher non-Faradaic current, low ohmic resistance of the influent, overlapping effect of electric double layers in micropore of the electrode. In addition, the CDI process using the IEE and brackish water shows much higher salt removal efficiency and lower salt removal rate than that using the IEE and mining water. This results from the lower concentration (i.e., higher ohmic resistance) and salt amount of the influent.