• Journal of Korean Society on Water Environment
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• v.20 no.1
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• pp.78-85
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• 2004

As an ozone contactor, we newly adopted HJLR (High-performance Jet Loop Reactor) for the decolorization of Reactive black 5 and the mineralization of oxalic acid, which has been applied exclusively in biological wastewater treatments and well-known for high oxygen transfer characteristics. The ozonation efficiency for organic removals and ozone utilization depending on the mass transfer rate were compared to those of Stirred bubble column reactor, which was controlled by varing energy input in the HJLR and Stirred bubble column reactor. The results were as follows; first, the decolorization rate of Reactive black 5 in the HJLR reactor was nearly proportional to the increasing $k_La$. When the $k_La$ was increased by 25 % from $13.0hr^{-1}$ to $16.4hr^{-1}$, 30 % of the k' (apparent reaction rate constant) was increased from 0.1966 to $0.2665min^{-1}$ (Stirred bubble column; from 0.1790 to $0.2564min^{-1}$). Ozone transfer was found to be a rate-determining step in decolorizing Reactive black 5, which was supported by that no residual ozone was detected in all of the experiments. Second, the mineralization of oxalic acid was not always proportional to the increasing $k_La$ in the RJLR reactor. The rate-determining step for this reaction was OH(OH radical) production with ozone transfer, because residual ozone was always detected during the ozonation of oxalic acid in contrast with Reactive black 5. This result indicates that the increase of $k_La$ in the HJLR reactor is beneficial only when there are in ozone transfer limited regions. In addition, regardless of $k_La$, the mineralization of oxalic acid was nearly accomplished within 60 minutes. It was interpreted as that the longer staying of residual ozone by whirling liquid in the HJLR reactor contributed to an high ozone utilization(83-94%), producing more OR radicals.

• Journal of Environmental Health Sciences
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• v.28 no.3
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• pp.1-8
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• 2002

The experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform as a general indicator organism based on chlorine, chlorine dioxide and ozone as disinfectants. The water sam-ples were taken from the outlet of settling basin in a conventional surface water treatment system that is provided with the raw water drawn from the mid-stream of the Han River. The inactivation of total coliform was experimentally ana-lyzed for the dose of disinfectant contact time, pH, Temperature and DOC. The nearly 2.4,3.0,3.9 log inactivation of total coliform killed by injecting 1 mか1 at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%(3 log), Disinfectants required were 1.70, 1.00 and 0.60 mか1 for chlorine, chlorine dioxide and ozone, respec-tively. The higher the pH is, the poorer the disinfections effects are in the range of pH 6-9 by using chlorine and ozone. But the irfluence of pH value on killing effects of chlorine dioxide is weak. The parameters estimated by the models of Chick-Watson, Hom, and Selleck from our experimental data obtained for chlorine are: log(N/ $N_{0}$ )=-0.16 CT with n= 1, log(N/ $N_{0}$ )=-0.71 $C^{0.87}$T with n$\neq$1, for Chicks-Watson model, log (N/ $N_{0}$ )= -1.87 $C^{0.47}$ $T^{0.36}$ for Hom model. For chlorine dioxide are: log(N/ $N_{0}$ )= -1.53 CT with n = 1, log(N/ $N_{0}$ )= -2.29 $C^{0.94}$T with n$\neq$1,, for Chicks-Watson model, log(N/ $N_{0}$ )= -3.64 $C^{0.43}$ $T^{0.24}$ for Hom model and for ozone are: log(N/ $N_{0}$ )= -2.59 CT with n = 1, log(N/ $N_{0}$ )= -2.28 $C^{0.36}$T with n$\neq$1, for Chicks-Watson model, log(N/ $N_{0}$ )= -4.53 $C^{0.26}$ $T^{0.19}$ for Hom model.19/ for Hom model.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.391-399
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• 2018

In this study, Diazinon which is the most widely used organophosphorus pesticides (OPPs) among pesticides was removed by ozone/hydrogen peroxide advanced oxidation process (Peroxone AOP). Diazinon is mainly found in groundwater, drinking water, rivers and ponds that are near agricultural areas using the pesticide. Accumulation of Diazinon on the body in the form of metabolites causes neurotoxicity, confusion, dizziness and vomiting. Diazinon is not easily removed by conventional water treatment processes. This study investigated the Diazinon removal characteristics with OH radicals with strong oxidizing power generated by using ozone and hydrogen peroxide. We determined optimal hydrogen peroxide/ozone injection molar ratio and confirmed the elimination reaction to initial Diazinon concentration, pH and DOC concentration, which are factors influencing the removal efficiency. Domestic researches on pesticide removal in the environment are much less than the cases of overseas. This study is expected to provide a basis for the process design for pesticide removal.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.586-592
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• 2015

This study was performed to determine optimum approaches for control of microorganisms in school refectories and kitchens. A reduction of more than 5.0 log CFU/mL was noted for Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Streptococcus mutans after treatment with 5 ppm ozone water for 60 s. Treatment of different vegetables with ozone water for 5 min showed bactericidal effects with 2-4 log reduction of viable cell number; the bactericidal effects differed according to the kinds of vegetables. The viable cell number on kitchen apparatus and tableware was not detected by ozone water treatment for 60 s. In addition, the count of the bacteria floating in the air in refectories and kitchens decreased 2.0 log CFU/1,000 L air to 0-1 CFU/1,000 L air on treatment with 45 ppm ozone gas for 12 hr. Therefore, ozone water and ozone gas may be good candidates as antimicrobial agents that can be used to improve sanitary conditions in school refectories and kitchens.

• Textile Coloration and Finishing
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• v.23 no.4
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• pp.274-283
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• 2011

Effect of pH on ozone oxidation and peroxone AOP(Advanced Oxidation Process) process was analyzed and the optimal efficiency for both processes was obtained at pH 7.5. In case of ozone oxidation process, the efficiencies of color, $COD_{Mn}$ and $BOD_5$ removal were measured to 93%, 70% and 89% at a reaction time of 50 min(ozone dosage of 111.67mg/$\ell$). When reaction time increased to 90 min(ozone dosage of 201mg/$\ell$), the efficiencies of color, $COD_{Mn}$ and $BOD_5$ removal were increased by 3~5 %, indicating that the increment of removal efficiency was insignificant considering longer reaction time. Similarly, the ozone/$H_2O_2$ ratio was optimized to 0.5 for peroxone AOP process. Removal efficiencies of color, $COD_{Mn}$ and $BOD_5$ were measured 95%, 81% and 94% at a reaction time of 50 min(ozone dosage of 111.67mg/$\ell$). When reaction time increased to 90min(ozone dosage of 201mg/$\ell$), the removal efficiency of color, CODMn, and BOD5 increased slightly by 1~5%.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.463-469
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• 2015

Bisphenol A (BPA) in aqueous solution was measured using HPLC technique, which was established by acetonitrile analysis and KDP solution analysis methods. In these experiments the decomposition characteristics of BPA were compared using the ozone alone, ozone/pH 10, and ozone/hydrogen peroxide processes. About 70% of 10 mg/L of BPA was removed during 60 min by the ozone alone process, while 10 mg/L of BPA was completely removed by the ozone/pH 10 and ozone/hydrogen peroxide processes in 40 min and 60 min, respectively. The final decomposition efficiency drawn from results of TOC and HPLC analyses showed that the ozone/hydrogen peroxide process was the best among them, whereas the concentrations of TOC and reaction intermediates when using the ozone/pH 10 process were higher than those of the ozone alone process after 60 min of reaction. The ozone/hydrogen peroxide process was the most efficient among them when oxidizing organic carbons in water to $CO_2$ and $H_2O$.

• Polymer(Korea)
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• v.27 no.2
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• pp.98-105
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• 2003

The surface energy and the effect of functional groups on the surface of the ozone-treated low-density polyethylene (LDPE) film were studied. Treatment conditions were treatment time, total amount of transferred ozone, and ozone concentration. The introduction of polar groups on the surface of LDPE film after ozone treatment was confirmed by FTIR-ATR and XPS analyses. Surface fee energy of the LDPE film was examined by a contact angle method. The ozone treated-LDPE film showed a decreased water contact angles about 15$^{\circ}$ mainly due to the increased concentration of oxygen-containing functional groups, which was attributed to the increased surface free energy or $O_{IS}/C_{IS}$Also, the concentrations of the oxygen-containing functional groups on the surface of LDPE film increased with ozone treatment time and concentration, whereas no significant effects were found for the total amount of transferred ozone. From the dyeability test using Kubelka-Munk equation, it was found that the ozone treatment plays an important role in the growth of oxygen-containing functional groups of LDPE film, resulting in the improvement of dyeability for basic dyeing agent.

• 수도
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• s.18
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• pp.59-72
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• 1979

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1378-1381
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• 1995

Some interesting electrochemical characteristics of waterpen point-to-plate airgaps for dc and ac powers have been investigated at room atmosphere in a metal chamber. It is found that the ac discharge on the Pt point generated much ozone, while the negative do discharge on the waterpen point generated the highest ozone. And, the ac discharges of the waterpen point and the Pt point produced a little $NO_x$. But the dc discharge of the Pt point and waterpen point did not generated $NO_x$ anyway. As a result, it could be said that the water on the pen point acts something to generate ozone and $NO_x$ in room atmosphere.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.45-48
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• 2001

The packed column experiments were conducted with a field soil, collected directly from the aquifer located at Bonchon industrial complex in K-city in order to characterize SOM reaction with ozone and to delineate the transformation of water soluble SOM after ozonation. As reaction time increased, water soluble organic matter increased, and this organic matter was in the range of 500∼1000 dalton. pH of extractants decreased with the increase of ozonation time. This Is because aromtic compounds in SOM were oxidized and carboxylic acid groups were formed. From the FT-IR spectra, the content of carboxylate increased as ozone injection time increased and hydroxyl group, which represents phenolic and alcoholic hydroxyl groups decreased. This is because oxidative ring fission formed carboxyl acid groups. This result provides a good agreement with pH decrease.