• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.109-117
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• 2010

In the present study, the degradation characteristics of Lindane by Advanced Oxidation Processes(UV/$H_2O_2$, Photo-Fenton process) were studied. The degradation efficiency of Lindane in aqueous solution was investigated at various initial pH values, Fenton's reagent concentrations and initial concentrations of Lindane. GC-ECD was used to analyze lindane. Lindane has not been degraded without application of AOPs over two hours. But, approximately 5% of lindane was degraded with UV or $H_2O_2$ alone. Lindane with UV/$H_2O_2$ process showed approximately 7% higher removal efficiency than $H_2O_2$ process. In the UV/$H_2O_2$ process, the pH values did not affect the removal efficiency. The optimal mole ratio of $H_2O_2/Fe^{2+}$ for lindane degradation is about 1.0 in Photo-Fenton process. Also, the experimental results showed that lindane removal efficiency increased with the decrease of initial concentration of lindane. Under the same conditions, the order lindane of removal efficiency is as following : Photo-Fenton process > UV/$H_2O_2$ process > $H_2O_2$ process. In addition, intermediate products were identified by GC-MS techniques. Than PCCH(Pentachlorocyclohexene) was identified as a reaction intermediate of the Photo-Fenton process.

• Journal of Environmental Science International
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• v.17 no.2
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• pp.203-210
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• 2008

The batch tests were performed to determine the ratio of Fenton reagent on diesel contaminated soil. The objective of a column test was to determine and optimize the hydrogen peroxide requirements for the remediation of a soil contaminated with diesel fuel. The batch test were done on 5 g diesel contaminated soil containing hydrogen peroxide (35%) and Iron (II) sulfate. The $H_2O_2(g):Fe^{2+}(g)$ ratio varied 1:0, 30:1, 15:1, 5:1, 1:1, with contact reaction time 120min. Initial diesel concentration were 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg. Average diesel removal from the contaminated soil is 97% after 2hrs. Results of this study showed possible application of without addition of iron source. In column test, treatment of a diesel-contaminated soil (initial diesel concentration: 2,000 mg/kg, 5,000 mg/kg, and 10,000 mg/kg) with hydrogen peroxide (35%) only was containing natural-occurring minerals. The time required for the column test was approximately 90min, 180min, 270min; column length was 5 em, 10 em, and 15 em. The most effective stoichiometry (final diesel cone.: $200{\sim}300mg/kg$) of 0.2 g peroxide consumed/mg diesel degraded. Further investigation is required to identify the effect of soil organic matter and soil mineral.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.6
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• pp.499-505
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• 2018

We applied column experiments to investigate the environmental fate and transport of silver nanoparticles(AgNPs) in fully saturated conditions of porous media. These column experiments were performed to emphasize oxidation method with $H_2O_2$ concentration and acidic conditions. The mobility of AgNPs was decreased with the increasing ionic strength that the surface charge of AgNPs(zeta potential) was neutralized with the presence of positive ions of $Na^+$. Additionally, it was also affected due to that not only more increased aggregated size of AgNPs and surface charge of quartz sand. The decreased breakthrough curves(BTCs) of bisphenol-A(BPA) and $17{\alpha}$-ethynylestradiol(EE2) were removed approximately 35.3 and 40%. This is due to that endocrine disrupting chemicals(EDCs) were removed with the release of $OH{\cdot}$ radicals by the fenton-like mechanisms from acidic and fenton-like reagent presenting. This results considered that higher input AgNPs with acidic conditions is proved to realistic in-situ oxidation method. Overall, it should be emphasized that a set of column experiments employed with adjusting pH and $H_2O_2$ concentration in proved to be effective method having potential ability of in-situ degradation for removing organic contaminants such as BPA and EE2.

• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.1-13
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• 1997

First- and second-order kinetic oxidation rates of trichlorobenzenes (TCBs) were obtained and compared by a chemical activation system (CAS) which mimics mixed functional oxidase activity. The system consists of EDTA, ferrous sulfate, ascorbic acid, and $H_2O_2$ in potassium phosphdte buffer (monobasic at pH 7.4). The rate of transformation in CAS was enhanced in the presence and absence of catalase in the sequence 1, 2, 3-TCB < 1, 2, 4-TCB < 1, 3, 5-TCB. In general, the rates of degradation were greater in the test media with catalase. The effect of photolysis on the degradation of the TCBs with the CAS were examined. Sensitized photolysis with nitrite, Fenton's reagent, TiO$_2$ and triethylamine (TEA) studied in concert with the CAS demonstrated significant enhancement of the degradation rate of TCBs. Disappearance rates of TCBs in CAS with prior photolysis or prior photosensitization were at least 10-fold higher than the sum of the rate for each single experiment. This study proves that the combination of the CAS and photolysis can be used as a suitable technique for enhancing degradation of TCBs in aqueous systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2771-2778
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• 2009

This study was performed to solve the problem of the 2nd contamination and excessive treatment cost by determining proper quantity of hydrogen peroxide, iron catalyst, mixing method, and input mode that should be provided when Fenton oxidation (this is mostly applied to small contaminated areas such as service station sites) is applied to the excavated and diesel-contaminated soil. Soil artificially contaminated with 10000mg/kg of diesel was used for the experiment. In the batch test, diesel removal seemed to increase as the concentration of hydrogen peroxide increases. When iron catalyst was added, removal efficiency of diesel was much higher than the time when hydrogen peroxide was added solely. The removal efficiency showed greater when Fe(III) was added compared to Fe(II). Column experiment was executed on the basis of results of the batch test to investigate adequate reagent mixing and input methods. The highest efficiency was acquired in the case of separate input mode. Also, it was found that when inputting Fe(III) iron catalyst and separately inputting hydrogen peroxide after dividing the bundle in the column, removal efficiency was 92.8%, which was 9 times greater than that of the first method, 10.5%, when only hydrogen peroxide was added. Thus, it is expected that if the result of this research is applied to Fenton oxidation for the remediation of soil contaminated by diesel, the problem of the 2nd contamination and excessive treatment charge caused by excessive addition of hydrogen peroxide and iron catalyst could be solved.

• Korean Journal of Environmental Agriculture
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• v.27 no.1
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• pp.86-91
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• 2008

Dicamba(3,6-dichloro-2-methoxybenzoic acid) is used to control for pre and post-emergence of annual and perennial broad-leaf weeds. It is very soluble in water and highly mobile, acidic herbicide. So it is easily moved and detected in groundwater. Zerovalent iron(ZVI) has been used for the reductive degradation of certain compounds through amination of nitro-substituted compounds and dechlorination of chloro-substituted compounds. In this study, we investigated the potential of ZVI for the oxidative degradation of dicamba in water. The degradation rate of dicamba by ZVI was more rapidly increased in pH 3.0 than pH 5.0 solution. The degradation percentage of dicamba was increased with increasing amount of ZVI from 0.05% to 1.0%(w/v) and reached above 90% within 3 hours of reaction. As a result of identification by GC-MS after derivatization with diazomethane, we obtained three degradation products of dicamba by ZVI. They were identified 4-hydroxy dicamba or 5-hydroxy dicamba, 4,5-dihydroxy dicamba and 3,6-dichloro-2-methoxyphenol. 4-Hydroxy dicamba or 5-hydroxy dicamba and 4,5-dihydroxy dicamba are hydroxylation products of dicamba. 3,6-dichloro-2-methoxyphenol is hydroxyl group substituted compound instead of carboxyl group in dicamba. We also confirmed the same degradation products of dicamba in the Fenton reaction which is one of oxidation processes using ferric sulfate and hydrogen peroxide. But we could not find out the dechlorinated degradation products of dicamba by ZVI.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.27-36
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• 2007

A recent study showed that MTBE can be degraded by Fenton's Reagent (FR). The treatment of MTBE with FR, however, has a definite limitation of extremely low pH requirement (optimum pH $3{\sim}4$) that makes the process impracticable under neutral pH condition on which the ferrous ion precipitate forming salt with hydroxyl anion, which result in the diminishment of the Fenton reaction and incompatible with biological treatment. Consequently, this process using only FR is not suitable for in-situ remediation of MTBE. In order to overcome this limitation, modified Fenton process using NTA, oxalate, and acetate as chelating reagents was introduced into this study. Modified Fenton reaction, available at near neutral pH, has been researched for the purpose of obtaining high performance of oxidation efficiency with stabilized ferrous or ferric ion by chelating agent. In the MTBE degradation experiment with modified Fenton reaction, it was observed that this reaction was influenced by some factors such as concentrations of ferric ion, hydrogen peroxide, and each chelating agent and pH. Six potential chelators including oxalate, succinate, acetate, citrate, NTA, and EDTA were tested to identify an appropriate chelator. Among them, oxalate, acetate, and NTA were selected based on their remediation efficiency and biodegradability of each chelator. Using NTA, the best result was obtained, showing more than 99.9% of MTBE degradation after 30 min at pH 7; the initial concentration of hydrogen peroxide, NTA, and ferric ion were 1470 mM, 6 mM, and 2 mM, respectively. Under the same experimental condition, the removal of MTBE using oxalate and acetate were 91.3% and 75.8%, respectively. Optimum concentration of iron ion were 3 mM using oxalate which showed the greatest removal efficiency. In case of acetate, $[MTBE]_0$ decreased gradually when concentration of iron ion increased above 5 mM. In this research, it was showed that modified Fenton reaction is proper for in-situ remediation of MTBE with great efficiency and the application of chelatimg agents, such as NTA, was able to make the ferric ion stable even at near neutral pH. In consequence, the outcomes of this study clearly showed that the modified Fenton process successfully coped with the limitation of the low pH requirement. Furthermore, the introduction of low molecular weight organic acids makes the process more available since these compounds have distinguishable biodegradability and it may be able to use natural iron mineral as catalyst for in situ remediation, so as to produce hydroxyl radical without the additional injection of ferric ion.

• Journal of Soil and Groundwater Environment
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• v.7 no.1
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• pp.25-31
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• 2002

This study attempts to elucidate the possibility of treating landfill leachate by steelers' dust/${H_2}{O_2}$ system in a well-mixed batch reactor. Experiments were conducted to investigate the effects of operating variables such as pH, dust and ${H_2}{O_2}$ dosages and ${H_2}{O_2}$ injection method on the treatment efficiency, Contaminant concentrations were identified by TOC (Total Organic Carbon) analyzer. Experimental observations showed the possibility of steelers' dust as a catalytic reagent in the ${H_2}{O_2}$/dust system. The batch experiments showed that the optimal $H_2O$$_2$ and dust dosage, 20g/L dust. 2,000mg/L ${H_2}{O_2}$ removed about 75% of initial TOC concentration (250mg/1) within 60 min. And the TOC removal in the ${H_2}{O_2}$/dust system effectively proceeded only within a limited pH range of 3-4. The stealers' dust-catalyzed oxidative treatment of landfill leachate was more efficient compared with the $FeSO_2$catalyzed system (Fenton oxidation) for the removal rate and the cost.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.76-82
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• 2006

This study was purposed to investigated the antioxidant effects of water (VLWS) and aqua-acupuncture solution (VLAS) from root of Vitis labrusca. VLWS and VLAS was were assessed to determine the mechanisms of its antioxidant activities. The VLWS and VLAS exhibitde a concentration-dependent inhibition of DPPH free radicals. This VLWS-mediated antioxidant activity was similar to that L-ascorbic acid (vitamin C). In addition, the VLWS and VLAS showed dose-dependent free radical scavenging activity, including superoxide anions and hydroxyl radicals, using different assay systems. The VLWS and VLAS were also found to be strongly inhibited linoleic acid oxidation in a ferric thiocyanate assay (FTC) system. Finally, the VLWS and VLAS significantly prevented Fenton's reagent-induced DNA nicking.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.977-983
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• 2002

This study was performed to establish the precise and rapid method to distinguish croakers through the pigment analysis of colored imported white croakers for adultration. We surveyed the coloring behaviors, extraction test by water and organic solvent and using pigments such as targeting, curcumine, and azo dye products. The pigment of yellow croaker is not stained on wet cloth or tissue which is rubbed on epidermis of yellow croaker and was not eluted in water extraction test, while adulterated pigments were easily extracted by water and acetone, but edible diluted yellow, Yellow No. 4 and Yellow No. 5 were not extracted. Reactive pigment was detected easily by extraction with water and dispersed pigment was also detected by extraction test. As a result of discoloring characteristics of carotene having similar structure to yellow croaker and azo dye by oxidation and reduction, azo dyes were not discolored by oxidation with sodium percarbonate or peracetic acid but that were discolored by oxidation with Fenton reagent after 1hr and by hypochlorite promptly. On the other hand, carotenes were not discolored by sodium precarbonate and Fenton reagent but discolored by sodium hypochlorite after 2 hr and by peracetic acid promptly. Azo dyes were discolored by reduction with sodium hydrosulfite and sodium carbonate but carotenes were not discolored by these reagents. This discoloring test was applicable to detect adulterated pigments and other marine product.