• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.105-111
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• 1997

Chlorine dioxide is being used to control THMs formation or taste & odor in water treatment plant. Recently, some operators or academic circles doubted the effectiveness of stabilized chlorine dioxide which is presumed as a liquid form of chlorine dioxide. In this study, we investigated components which consist of stabilized chlorine dioxide in terms of chlorine dioxide and chlorite. Two analytical methods used in this study are UV method and Iodometric method. Iodometric method is recommended by Korean EPA to check the purity of stabilized chlorine dioxide. The samples of stabilized chlorine dioxide from four water treatments were investigated and compared with that produced from chlorine dioxide generator on-site. This study demonstrated that the component of stabilized chlorine dioxide was overwhelmingly chlorite (${ClO_2}^-$) not chlorine dioxide ($ClO_2$) by UV method. It was also proved that Iodometric method (2nd method) recommended by Korean EPA could not differentiate between $ClO_2$ and ${ClO_2}^-$. Iodometric method (2nd method) recommended by Korean EPA should be revised accordingly to measure chlorine dioxide properly.

• Journal of Environmental Health Sciences
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• v.25 no.3
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• pp.83-88
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• 1999

This study was carried out to examine the behavior of THM formation in water treated with chlorine dioxide where humic acid was used as THM precursor. THM was not detected in bromide-free water, but formed in water containing bromide. When 10 mg/l of chlorine dioxide was added to water containing 5 mg/l of humic acid and bromide respectively, 20.46 ${\mu}$g/l of THM was formed. It is postulated that chlorine dioxide oxidize bromide to hydrobromous acid, which subsequently reacted with humic acids similar to chlorine reaction. The formation of THM could be reduced at low pH. Among THM formed, CHBr$_3$ was the predominant species in the alkaline solution, while CHCl$_3$ in the acidic solution. A sample pretreated with chlorine dioxide for 24h before addition of chlorine showed a reduction of 75.1% in THM formation, compared with a sample not pretreated with chlorine dioxide and a sample treated by chlorine for 24h prior to addition of chlorine dioxide also showed a reduction of 37.8% in THM formation, compared with a sample not added with chlorine dioxide. It may explain that chlorine dioxide oxidizes directly a fraction of THM.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.140-143
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• 2003

This research was to determine and compare the inactivation of total coliform as the indicator organism with chlorine, chlorine dioxide and ozone for drinking water treatment. The inactivation of total coliform was experimentally analyzed for the dose of disinfectant, contact time, pH, Temperature and DOC. 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 nearly 2.4, 3.0, 3.9 log inactivation of total coliform killed by injecting 1mg/L at 5 minutes for chlorine, chlorine dioxide and ozone. For the inactivation of 99.9%, Disinfectants required were 1.70, 1.00 and 0.60 mg/L for chlorine, chlorine dioxide and ozone, respectively. The bactericidal effects of disinfectants were decreased as the pH increased in the range of pH 6-9. The influence of pH change on the killing effect of chlorine dioxide was not strong, but that on ozone and free chlorine was sensitive. The bactericidal effects of the disinfectants were increased as the temperature increase. The activation energies were 36,053, 29,822, 24,906 J/mol of chlorine, chlorine dioxide, ozone for coliforms. The inactivation effects were shown in the lowest order of chlorine, chlorine dioxide and ozone.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.211-215
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• 2020

Currently, most of the chlorine dioxide gas is processed at the beginning of storage or distribution. It has the disadvantage of not being able to continuously process gas since there is no system that can continuously process it during the distribution process. Therefore, in order to minimize changes in freshness and quality during the distribution process of agrifood, there is a need for a sustained-release chlorine dioxide gas treatment technology that can be continuously released. Therefore, in this study, the film to be used was examined so that the chlorine dioxide gas can be continuously released for a certain period of time, the concentration of the reactant and the viscosity at the time of the reaction were determined, and a chlorine dioxide gas gel pack was manufactured using this optimal condition. In addition, the gel pack was used to measure the amount of chlorine dioxide gas released and the sterilization effect of food poisoning bacteria.

• Food Science and Biotechnology
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• v.16 no.6
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• pp.1018-1022
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• 2007

Effect of aqueous chlorine dioxide treatment on the microbial growth and quality changes of strawberries during storage was examined. Strawberries were treated with 5, 10, and 50 ppm of chlorine dioxide solution, and stored at $4{\pm}1^{\circ}C$. Total aerobic bacteria in strawberries treated at 50 ppm of chlorine dioxide were increased from 1.40 to 2.10 log CFU/g after 7 days, while increasing in the control from 2.75 to 4.32 log CFU/g. Yeasts and molds in strawberries treated at 50 ppm of chlorine dioxide were increased from 1.10 to 1.97 log CFU/g after 7 days, while the control was increased from 2.55 to 4.50 log CFU/g. The pH and titratable acidity of strawberries were not significantly different among treatments. Sensory evaluation results showed that chlorine dioxide-treated strawberries had better sensory scores than the control. These results indicate that chlorine dioxide treatment could be useful in improving the microbial safety and qualities of strawberries during storage.

• Analytical Science and Technology
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• v.12 no.5
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• pp.403-407
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• 1999

A method for detecting chlorine dioxide in drinking water was developed by the modified iodometric titration. This method requires prior removal of interfering chemicals such as chlorine and/or other oxidants: the interferents are removed by $N_2$ purging. Chlorite and chlorate were successfully quantified by the ion chromatography-conductivity detection. Stabilized chlorine dioxide that is commercially available contained only traces of chlorine dioxide (0.01-0.09%). In reality, its main component is chlorite.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.5
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• pp.601-604
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• 2009

This study was conducted to examine the effect of aqueous chlorine dioxide treatment as a washing method on removal of pesticide residues. Three pesticides of chlorpyrifos, diazinon, and metalaxyl, which are commonly used in vegetable crops, were treated with 10, 50, and 100 ppm of aqueous chlorine dioxide and decomposition of the pesticides was determined using gas chromatography. Three pesticides used in this study were decomposed by aqueous chlorine dioxide treatment and removal rate was proportional to treatment time as well as concentration of aqueous chlorine dioxide. In particular, 100 ppm of aqueous chlorine dioxide treatment decreased the pesticides efficiently. In addition, lettuce was treated by dipping in distilled water and 100 ppm aqueous chlorine dioxide, respectively, and was compared regarding removal efficiency of the pesticides. The results revealed that washing with 100 ppm aqueous chlorine dioxide for 10 min was the most effective for removing the pesticides. These results suggest that aqueous chlorine dioxide can be used as a washing method of fresh produce to remove the residual of pesticides.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.282-291
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• 2006

This study investigated the inactivation of the total coliform, an indicator organism in chlorine and chlorine in order to control microbial regrowth for water distribution systems and select an appropriate disinfection strategy for drinking water systems. The disinfection effects of chlorine and chlorine dioxide with regard to the dosage of disinfectant, contact time and DOC was investigated experimentally. In spite of the consistency of chlorine residuals at approximately 0.2 mg/l, bacteria regrowth was detected in the distribution system and it was confirmed by the scanning electron microscope results. The influence of organic carbon change on the killing effect of chlorine dioxide was strong.

• Journal of Korean Society of Water and Wastewater
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• v.7 no.2
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• pp.24-33
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• 1993

The effects of chlorine dioxide on the oxidation of phenol and disinfection were studied in the various test water conditions. With the 0.3mg/l of chlorine dioxide dose, the spiked phenol(initial concentration: 0.1mg/l) was completely oxidized within 10 minute. The removal rate of phenol was much faster in distilled water than in ground water and filtered water. The applied dose of chlorine dioxide concentrations higher than 0.2mg/l was sufficiently enough for the complete oxidation of phenol. However, with 0.1mg/l of dose, chlorine dioxide can oxidize only 20% of the spiked phenol. The reactive substances present in test water may influence the chlorine dioxide demand in water. pH effect of oxidation rate was also investigated. Increasing the pH, the removal rate of phenol was found to be increased. The disinfection test of chlorine and chlorine dioxide were conducted and compared. The lethal effect for the both disinfectants are similarly powerful. The time for 99% inactivation of E. coli was obtained within 120 sec with the 0.2mg/l of each dose.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.78-83
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• 1999

In this paper the extinction coefficients of molecule chlorine ($Cl_2$), chlorine dioxide (ClO$_2$), hypochlorous acid (HClO), chlorous acid ($HClO_2$$_2$) were determined using a PDA UV-VIS spectrophotometer. Based on these, the concentrations of $Cl_2$, $ClO_2$, and HClO in general chlorine dioxide bleaching liquor can be measured. The concentrations of $Cl_2$, $ClO_2$ and $HClO_2$ produced during the generation of methanol based chlorine dioxide generator can also be determined use the same method. The method was thought to be able to give more information in chlorine dioxide bleaching chemistry if combine its use with titration and ion chromatography.