• 한국환경보건학회지
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• 제26권4호
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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.

• 한국응용과학기술학회지
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• 제30권3호
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• pp.518-527
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• 2013

5,6-dihydroxyindole was easily oxidation with air and light Conditions. Availability of 5,6-dihydroxyindole was studied for hair dye as a precursor of melanin. This study used wet and dry coating process to stabilize 5,6-dihydroxyindole. In wet process used dimethicone and cyclometicone, the 5,6-dihydroxyindole had darkened through the drying process at $58^{\circ}C$. Wet coating process was inappropriate to stabilize the coating. In dry coating process, shea butter coating was stable until 3 days. Dextrin palmitate was most efficient ingredient to prevent oxidation by sun light and air until 7days. Oxidation test with 1.0% and 1.5% of dextrin palmitate was not different under conditions of sun light and air and was not dependent on contents. Vitamin E acetate under conditions of sun light and air, there were no significant effect in preventing oxidation.

• Journal of Electrochemical Science and Technology
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• 제3권1호
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• pp.44-49
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• 2012

Electrochemical and photochemical techniques have been proved to be effective for the removal of organic pollutants in textile wastewater. The present study deals with degradation of synthetic textile effluents containing reactive dyes and assisting chemicals, using electro oxidation and photo catalytic treatment. The influence of various operating parameters such as dye concentration, current density, supporting electrolyte concentration and lamp intensity on TOC removal has been determined. From the present investigation it has been observed that nearly 70% of TOC removal has been recorded for electrooxidation treatment with current density 5 mA/$dm^2$, supporting electrolyte concentration of 3 g/L and in photocatalytic treatment with 250 V as optimum lamp intensity nearly 67% of TOC removal was observed. The result indicates that electro oxidation treatment is more efficient than photocatalytic treatment for dye degradation.

• 한국환경과학회지
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• 제18권11호
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• pp.1225-1234
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• 2009

The aim of this research was to apply experimental design methodology in the optimization condition of electrochemical oxidation of Rhodamine B(RhB). The reactions of electrochemical oxidation were mathematically described as a function of parameters amounts of current, NaCl dosage, pH and time being modeled by the use of the central composite design, which was used for fitting quadratic response surface model. The application of response surface methodology using central composite design(CCD) technique yielded the following regression equation, which is an empirical relationship between the removal efficiency of RhB and test variable in actual variables: RhB removal (%) = 3.977 + 23.279$\cdot$Current + 49.124$\cdot$NaCI - 5.539$\cdot$pH - 8.863$\cdot$time - 22.710$\cdot$Current$\cdot$NaCl + 5.409$\cdot$Current$\cdot$time + 2.390$\cdot$NaCl$\cdot$time + 1.061$\cdot$pH$\cdot$time - $0.570{\cdot}time^2$. The model predicted also agree with the experimentally observed result($R^2$ = 91.9%).

• 한국물환경학회지
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• 제29권2호
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• pp.204-211
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• 2013

In this study, the deriving optimum conditions for decolorization of Acid Orange II solution was carried using $TiO_2$ advanced oxidation process. After that, on base of the deriving results, the range of dye concentration was estimated. In addition, acute toxicity test was also carried to assess toxicity unit according to decolorization and TOC removal. In case of the blockage of light, 20 mg/L of dye solution, and 0.5 g $TiO_2$, the effect of decolorization at pH 3 was larger than at pH 6 and 10, so it was shown that decolorization is dependent on pH. The use of 5 g $TiO_2$ showed best performance of decolorization, but that of 3 g $TiO_2$ was chosen to optimum condition in considering of economical aspects. Four light sources, sun, fluorescent lamp, BLB lamp, and UV-B lamp, were used and decolorization was 99.4% and 100% at 50 mg/L, 98.6% and 99.7% at 100 mg/L for sun and UV-B lamp, respectively. In spite of the optimum condition of decolorization at pH 3, the evaluation of acute toxicity test showed highly toxic. In conclusion, although the optimum treatment of dye solution is performed, water ecology can be polluted in discharging it into water system. Therefore, it is needed to study of water ecological system with dye water treatment, and it takes all the circumstances into consideration.

• 한국환경과학회지
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• 제8권4호
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• pp.539-545
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• 1999

Dye wastewater was treated by using an electrochemical oxidation process. Various combinations of electrodes such as carbon, Al and Fe were investigated. In this study, electrode material, electrolyte concentration, electrode distance, current density, and pH value were found to have significant effect on both pollutant removal efficiency and current efficiency in electrochemical oxidation process. After electrolysis for 40min with carbon/Al, it was observed that COD, $T-N, NH_{4}^{+}-N$ and color of treated wastwater were reduced from 580mg/$\ell$ to 145mg/$\ell$, 67.2mg/$\ell$ to 26.8mg/$\ell$, 46.8mg/$\ell$ to 1.4mg/$\ell$, and 4200 Pt-Co units to 336 Pt-Co units, respectively. The optimal conditions of the electrooxidation process to treat the wastewater for this study were found to be such : current density ; 16.67mA/$cm^2$, electrode distance ; 2.5cm, pH value ; 5.0 and carbon/Al electrode.

• 한국환경과학회지
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• 제15권1호
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• pp.67-75
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• 2006

The degradation of Rhodamine B (RhB) in water was investigated in laboratory-scale experiments, using five advanced oxidation Processes (AOPs) $UV/H_2O_2$, lenten, photo-lenten, $UV/TiO_2,\;UV/TiO_2/H_2O_2$. The photodegradation experiments were carried out in a fluidized bed photoreactor equipped with an immersed 32 W UV-C lamp as light source. initial decolorization rate and COD removal efficiency were evaluated and compared. The results obtained showed that the initial decolorization rate constant was quite different for each oxidation process. The relative order of decolorization was: photo-fenton > $UV/TiO_2/H_2O_2$ > fenton > $UV/H_2O_2$ > $UV/TiO_2$ > UV > $H_2O_2$. The relative order of COD removal was different from decolorization: photo-fenten ${\fallingdotseq}$ $UV/TiO_2/H_2O_2\;>\;UV/TiO_2\;>\;fenton\;>\;UV/H_2O_2$. The Photo-lenten and $UV/TiO_2/H_2O_2$ processes seem to be appropriate for decolorization and COD removal of dye wastewater.

• 한국지반환경공학회 논문집
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• 제7권3호
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• pp.21-29
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• 2006

난분해성 염색폐수를 처리하기 위한 화학적 처리 방법으로 오존단독처리와 3가지 경우의 고도산화공정[AOPs($O_3/H_2O_2$, $O_3/UV$, $O_3/H_2O_2/UV$)]의 처리특성을 실험적으로 검토하였다. 각각의 처리방법에서 합성 염색폐수를 대상으로 $COD_{cr}$ 및 색도의 제거효율, 생분해도(biodegradability)향상에 대한 처리특성을 상대적으로 비교 평가하였고 pH, 온도, 주입량, 순환유량 등을 주요운전인자로 하여 각 산화공정의 최적운전 조건을 파악하였다. 대상으로 한 모든 공정에서 염색폐수의 색도는 단시간에 대부분 제거되었지만, $COD_{cr}$ 제거측면과 생분해도 향상에서는 $O_3/H_2O_2/UV$ 공정이 가장 좋은 처리효율을 나타냈다.

• 한국염색가공학회지
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• 제22권2호
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• pp.101-109
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• 2010

The objective of this study is to investigate the characteristics of natural indigo dyeing of cotton fabric. Reduction and dyeing were carried out by one-step process using an infrared dyeing machine at the liquor ratio of 1:100, and subsequently oxidation and washing in water were followed. Dye uptake was increased with the increase of indigo concentration. Over the full range of dyeing tests, the dyeing condition was optimized to $40^{\circ}C$ for 40min. For most of dye concentrations, the cotton fabrics showed mainly PB color. Maximum K/S value was shown at 4g/L of sodium hydrosulfite concentration and the color strength increased with the increase of dye concentration. Value(lightness) decreased with the increase of dye uptake irrespective of mercerization or reduction method, while the mercerized cotton showed two times higher dye uptake than the untreated cotton. Whereas hue of the untreated cotton showed large decrease of P character(5.6~3.5 PB) with the increase of dye uptake, that of the mercerized cotton increased P character(4.7~5.5 PB). Irrespective of mercerization, value and chroma decreased with the increased of dye uptake. In addition, the untreated showed lower chroma than the mercerized cotton. In the case of traditional reduction, hue of the untreated cotton was changed very little with the increase of dye uptake. For hydrosulfite reduction, P character decreased with the increase of dye uptake. The difference of hue value was small with the change of reduction method(hydrosulfite reduction or traditional fermentation). Color character was not influenced by the changed maximum absorption wavelength. Washing fastness showed 4~4/5 shade change rating without any staining. And dry rubbing fastness was good at low color strength. The bacterial reduction ratios of dyed cotton fabric were also increased.

• 한국물환경학회지
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• 제25권5호
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• pp.758-763
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• 2009

This study presents the optimal conditions of zero-valent iron (ZVI) pretreatment for color removal from real dye wastewater. Removal of color by ZVI was strongly subject to the acidity of the wastewater buffering the pH increased after ZVI reduction. The real dye wastewater did not contain a sufficient amount of acidity and thus it was necessary to supplement acid to the dye wastewater before treatment. In continuous operation of iron column, the empty bed contact time (EBCT) and initial pH were varied to find the optimal conditions. A non-linear regression model fitted well the experimental result predicting that the optimal EBCT and pH for 80% removal efficiency was present in the range of 57~90 and 5~5.9, respectively. Color of column effluents could be further removed in the following biological oxidation step and the biodegradability of wastewater was also enhanced after iron pretreatment.