• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1997.05a
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• pp.53-56
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• 1997

오염된 토양의 복원기술 개발의 일환으로 폐수의 처리 등에 많이 이용되어온 Fenton-like oxidation을 petroleum으로 오염된 토양의 in-situ/ex-situ remediation을 위한 data 축적을 위해 실험실상에서 적용하여 보았다. 천연 토양속에 흔히 존재하는 철광석의 한 형태인 magnetite, goethite를 이용해 Fenton-like oxidation을 유도하여 silica sand에 오염된 kerosene의 분해를 잔존 TPH의 분석을 통하여 확인하였다. 초기 kerosene의 농도, 과수의 농도, 철광석의 양을 변수로 하여 최적 처리조건을 구하기 위한 실험을 진행하였다.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.110-119
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• 2004

The combination of biological and physical/chemical technologies is a promising technique to reduce highly concentrated pollutants in livestock wastewater. It is suggested to treat livestock wastewater efficiently as follows: firstly, biodegradable organic matters, nitrogen and some of phosphorus should be removed by a biological treatment process and then residual non-biodegradable organic matters, color and phosphorus be eliminated by physicochemical technologies. In this study, therefore, the integrations of chemical coagulation, activated carbon adsorption, Fenton oxidation and ozonation were evaluated to provide appropriate post-treatment processes for biologically pre-treated livestock wastewater. After chemical coagulation followed by ozonation or Fenton oxidation process, the quality of treated wastewater could meet the discharge limit in Korea. However, a yellowish brown color still remained in the treated wastewater after a single method such as coagulation and Fenton oxidation was applied. The ozonation was found to be the most effective technology for the decolorization. Neither simple biological nor physicochemical treatment provides adequate decolorization and sufficient depletion of organics in livestock wastewater so far. Consequently, the integration of Fenton oxidation and ozonation with a biological treatment process is recommended to treat livestock wastewater in terms of removal efficiency.

• Environmental Engineering Research
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• v.19 no.1
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• pp.9-14
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• 2014

Fenton reaction with zerovalent iron (ZVI) and $Fe^{2+}$ ions was studied to treat pharmaceutical wastewaters (PhWW) including antibiotics and non-biodegradable organics. Incremental biodegradability was assessed by monitoring biochemical oxygen demand (BOD) changes during Fenton reaction. Original undiluted wastewater samples were used as collected from the pharmaceutical factory. Experiments were carried out to obtain optimal conditions for Fenton reaction under different $H_2O_2$ and ion salts (ZVI and $Fe^{2+}$) concentrations. The optimal ratio and dosage of $H_2O_2$/ZVI were 5 and 25/5 g/L (mass basis), respectively. Also, the optimal ratio and dosage of $H_2O_2/Fe^{2+}$ ions were 5 and 35/7 g/L (mass basis), respectively. Under optimized conditions, the chemical oxygen demand (COD) removal efficiency by ZVI was 23% better than the treatment with $Fe^{2+}$ ion. The reaction time was 45 min for ZVI and shorter than 60 min for $Fe^{2+}$ ion. The COD and total organic carbon (TOC) were decreased, but BOD was increased under the optimal conditions of $H_2O_2$/ZVI = 25/5 g/L, because organic compounds were converted into biodegradable intermediates in the early steps of the reaction. The BOD/TOC ratio was increased, but reverse-wise, the COD/TOC was decreased because of generated intermediates. The biodegradability was increased about 9.8 times (BOD/TOC basis), after treatment with ZVI. The combination of chemical and biological processes seems an interesting combination for treating PhWW.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.23-25
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• 2002

This study was conducted to understand characteristics of wastewater which is discharged from small-scale dyehouse located in Seoul downtown area and to Find the appliable treatment method on the spot. The results of this study were summarized as followings. 1. The method which is used at present is mostly flocculation by coagulant or fenton oxidation. But the treatment efficiency of them are not good. 2. The results of fenton oxidation experiment demonstrated that treatment efficiency of COD was limited, which showed the need of the additional process or the improvement of existing treatment method, while the color was reduced considerably in optimal condition. 3. The optimal condition of fenton oxidation are as followings. -Feasible pH was in the 3∼4 regardless of the kinds of iron ions, But the fluctuation of treatment efficiency with the change of pH was small - The mass ratio of H$_2$O/CODcr was used to evaluate the parameter of H$_2$O$_2$ The optimal range of this was in 0.7∼1,3 and it was observed that the ratio got higher as the quality got worse. -For iron ion, FeCl$_2$4H$_2$O turned out to be more effective for removal of color compared with was compared FeSO$_4$7H$_2$Oin. the mass ratio of Fe/H$_2$O$_2$ of 2.3∼2.8 for of FeSO$_4$7H$_2$O and 1.6∼1.8 for FeCl$_2$4H$_2$O resulted in good treatment efficiencies. 4. With adsorption process applied before fenton oxidation in order to treat the high concentration wastewater, the treatment efficiency increased by 61％ in CODcr, 55％ in color. and if the power activated carbon is injected in more than 2500mg/$\ell$, the wastewater can be treated within the effluent quality criteria.

• Journal of the Korean GEO-environmental Society
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• v.11 no.10
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• pp.49-55
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• 2010

The oil spill occurred frequently due to probably the increased consumption of oil as the energy source and the raw materials of various chemicals. For the treatment of oil contaminated groundwater, DAF(Dissolved Air Flotation) is being used but the removal efficiency is low. Therefore it is necessary to reduce the free phase oil, oil-in water type or water-in oil type emulsified oil, and soluble oil which are the main sources of contaminated groundwater. In this study, treatment of contaminated groundwater was performed using the Fenton oxidation process. The optimum conditions for the removal of THP(Total Petroleum Hydrocarbon) were 3 of pH, 25mM of $H_2O_2$ concentration and 25mM of $Fe^{2+}$ concentration. THP and COD(Chemical Oxygen Demand) concentrations decreased less than 1.5mg/L and 40.0mg/L in 7 minutes using DAF and Fenton oxidation process. However it is necessary to install the settling basin as the sludge concentration increased approximately 5 times.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E1
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• pp.16-28
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• 2007

An improved method was developed to determine gas-phase hydrogen peroxide($H_2O_2$) and organic hydro-peroxides (ROOH) in real-time, The analytical system for $H_2O_2$ is based on formation of hydroxybenzoic acid (OHBA), a strong fluorescent compound. OHBA is formed by a sequence of reactions, photoreduction of Fe(III)-EDTA to Fe(II)-EDTA, the Fenton reaction of Fe(II)-EDTA with $H_2O_2$, and hydroxylation of benzoic acid. By use of this analytical method rather than a previous similar method, Fenton reaction time was reduced from 2 min. to 30s. Air samples were collected by a surfaceless inlet to prevent inlet line losses. With a special arrangement of the sampling apparatus, sample delivery time was drastically reduced from ${\sim}5\;min\;to\;{\sim}20\;s$. The automated system was found to be sensitive, capable of continuous monitoring, and affordable to operate. A comparison of this method with a well-established one showed an excellent linear correlation, validating applicability of this technique to $H_2O_2$ determination. The system was applied to field measurements conducted during summertime of 2004 in Gwangju, South Korea. $H_2O_2$ was found to be a predominant species of peroxides. The diurnal variation of $H_2O_2$ displayed the maximum in early afternoon and the broad minimum throughout night. $H_2O_2$ was correlated positively with ozone, photochemical age, and temperature, however, negatively with $NO_x$ and relative humidity.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.47-53
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• 2004

Feasibility of electrokinetic process combined with Fenton-like reaction was investigated for the removal of phenanthrene from contaminated soil. Transport of hydrogen peroxide by electroosmosis and decomposition of phenanthrene by Fenton-like reaction were observed in a model system. Electrical potential gradient and electroosmotic flow (EOF) at 10 mA were higher than those at 5 mA. High accumulated EOF resulted in high removal efficiency of phenanthrene because the large amount of hydrogen peroxide was transfered through the soil. Removal efficiency of phenanthrene by water washing was 8.5% for 7 days. The highest removal efficiency including phenanthrene decomposition was 95.6% for 14 days. After the operation, soil samples with removal efficiency of 95.6% showed low concentrations of phenanthrene and its intermediates. From this result, it was presumed that phenanthrene was decomposed to small molecules or mineralized to water and carbon dioxide due to continuous supply of hydrogen peroxide by electroosmotic flow.

• Advances in environmental research
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• v.5 no.3
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• pp.189-200
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• 2016

This study aimed at advanced oxidation of hetero tri-functional reactive dye Acid orange 7 using photo-Fenton conditions in a lab-scale experiment. Decolourisation of Acid Orange 7 dye by Fenton's process was dependent on concentration of Hydrogen peroxide, Ferrous sulphate, pH, and contact time. A $2^3$ factorial design was used to evaluate the effects of these key factors: pH, Fe(II), and $H_2O_2$ concentration, for a dye concentration of 50 mg/L with COD of 340 mg/L at pH 3.0. The response function was removal of colour under optimised conditions; pH 3.0, [Fe(II)] 40.83 mg/L, [$H_2O_2$] 4.97 mmol/L; 13.6 min. of treatment resulting in 100% colour removal. The final COD of treated wastewater was nil suggesting that AOP is a potentially useful process of color removal and dye degradation/mineralisation of effluent having AO7. Minimum contact time for complete decolourisation was at 5 mmol/l $H_2O_2$ concentration. Increase in $FeSO_4$ (mg/l) concentration resulted in decrease of time for complete decolourisation. Box-Behnken Design was used to optimize the process variables. Maximum and minimum levels of pH (3-5), $H_2O_2$ (4-6 mmol/l), $FeSO_4$ (30-46 mg/l) and contact time (5-15 minutes) were used. The statistical analysis revealed a value of 0.88 for coefficient of regression ($R^2$) indicating a good fit of model. Calculated F-value was found higher than the tabulated value confirming to significance of the model. Based on student's t-test, Ferrous sulphate, pH, and contact time have a positive effect on the percent decolourisation of Acid Orange 7.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.597-601
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• 2006

The degradation of the Nafion membrane by oxygen radical (OH, $HO_2$) was investigated in Polymer electrolyte membrane fuel cell (PEMFC). Nafion membrane was degraded in Fenton solution consisted with hydrogen peroxide (10-30％) and ferrous ion (1-4 ppm) at $80^{\circ}C$. After degradation in Fenton solution, C-F, S-O and C-O chemical bonds of membrane were broken by oxygen radical attack. Breaking of C-F bond reduced the mechanical strength of Nafion membrane, and hence induced pinholes, resulting in increase of $H_2$ crossover through the membrane. Decomposition of S-O and C-O bonds decreased the ion exchange capacity of the electrolyte membrane. The performance of unit cell composed the membrane, which was degraded in 30％ $H_2O_2$ with 4ppm $Fe^{2+}$ solution for 48 hr, was about half times as low as one with normal membrane.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.14-23
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• 2018

$TiO_2-coated$ cubic ${\alpha}-Fe_2O_3$ with mostly exposed (012) and (101) facets (${\alpha}-Fe_2O_3@TiO_2$) was fabricated using a hydrothermal route for the photo-Fenton degradation of tetracycline under visible light irradiation. $TiO_2$ coating could greatly affect the photocatalytic activity of ${\alpha}-Fe_2O_3@TiO_2$. Compared with cubic ${\alpha}-Fe_2O_3$ alone for photodegradation of tetracycline, ${\alpha}-Fe_2O_3@TiO_2$ with $TiO_2$ shell of around 15 nm exhibited higher removal efficiency of tetracycline in photo-Fenton system, and its durability was slightly affected after five cycle times under same conditions. It is ascribed to the well-matched interface between cubic ${\alpha}-Fe_2O_3$ core and $TiO_2$ shell, leading to the broadened light-absorption and the efficient separation of photo-generated electon-hole pairs. The $^{\bullet}OH$ radicals were main responsible for the advanced photocatalytic performance of ${\alpha}-Fe_2O_3@TiO_2$ in visible-light driven degradation of tetracycline.