• 한국연초학회지
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• 제9권2호
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• pp.25-35
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• 1987

Effects of application time And rate of chlorine on the chlorine absorption and distribution at different stalk positions of the plants were Investigated in burley tobacco grown under the pot condition. Treatment consisted of 6 application times (from 2 weeks before transplanting to 8 weeks after transplanting with 2 weeks' interval) and 2 application rates (2g and 4g-KCl/pot) by 6X2 factorial experimental design. The tobacco plants took up the chlorine rapidly just after chlorine application, and the chlorine content of leaf was increased proportionally to the rate of chlorine application. The chlorine was accumulated when much in lower leaves when chlorine was applied early, while the chlorine accumulated much in upper leaves when chlorine was applied late. The chlorine content of leaf was negatively correlated to the degree of brightness, red color and yellow color of cured leaf. Significant Increases In cured leaf ratio, leaf thickness, leaf weight and weight Per unit leaf area of harvested leaf were obtained with increased chlorine application. When the chlorine was applied early, the leaf weight showed Increasing tendency.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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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.

• 한국물환경학회지
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• 제21권2호
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• pp.176-183
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• 2005

Chlorination of wastewater is recently practiced in Korea. While many researchers have studied the kinetics of aqueous chlorine(HOCl) with nitrogeneous compounds and other organic/inorganic contaminants in drinking water, the researches of wastewater chlorination are relatively few. The purpose of this study was to investigate the chlorine decay kinetics and parameters on wastewater chlorination. Chlorine decay rate increased with increasing initial chlorine concentration. The parameters affecting chlorine decay rate were different in each wastewater treatment plant. One of the most important parameters affecting chlorine decay was initial chlorine concentration, and other parameters such as $NH_3-N$, total coliform, $UV_{254}$ and Fe were also affected. The decay ratio of chlorine was decreased with increasing initial chlorine concentration, and the disinfection efficiency showed good correlation with the decay ratio.

• 상하수도학회지
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• 제23권3호
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• pp.331-337
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• 2009

Electrolysis produces hypochlorous acid by using a small quantity of NaCl as electrolyte. This process maximizes the stabilization of drinking water through the control of chlorine residual concentration. This study investigated free chlorine generation by an electrolytic method using $Ti/IrO_2$ and stainless steel. The generation of free chlorine was increased with increasing hydraulic retention time, voltage, chlorine ion concentration and the number of electrodes. However, the change of pH did not affect the generation of free chlorine. There was no significant difference on the behavior of chlorine concentration between electrolytic method and NaOCl injection. In this study, the concentration of free chlorine predicted model based on power functional model was developed various under conditions. Electrolysis free chlorine generation model can be effective tool in the estimation of free chlorine generation.

• 한국환경보건학회지
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• 제25권3호
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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.

• 한국연초학회지
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• 제8권1호
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• pp.49-56
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• 1986

To obtain the information of low chlorine leaf production, the chlorine content of the soil and cured leaf in Burley tobacco growing area was investigated. The results obtained are as follows. 1. The chlorine concentration in soil at transplanting time in Kwang-ju growing area was higher than in Jeon-ju(1983), and paddy field sell showed higher concentration of chlorine than upland field in Jeon-ju(1984). The chlorine concentration in soil was different between years, locations, and cultivated land (paddy field and upland field), but the concentration, on the whole, was under the levels that might effect the leaf quality. 2. The chlorine concentration In soil was highest around todays after transplanting, and after harvesting, the concentration decreased to half of transplanting time. 3. The distribution of chlorine through the parts of tobacco plant showed remarkable difference between years, locations, cultivated land and growing stages. 4. There was significant positive correlation between chlorine concentration in top soil and chlorine content of cured leaf. 5. Chlorine content of cured leaf in Kwang-ju area(1.79%) was higher than that of Jeon-ju area(O.79%), relatively. 6. It was considered that the accumulation of salt from the sea by sea. wind did not main factor of high leaf chlorine content in seaside district.

• 한국환경보건학회지
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• 제32권4호
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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.

• 상하수도학회지
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• 제11권2호
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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.

• 한국잠사곤충학회지
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• 제42권2호
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• pp.78-82
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• 2000

In this study, a comparative removal of chlorine from aqueous solutions of mulberry leaf powder(MLP) and activated carbon(AC) was investigated. The chlorine removal capacities of MLP and AC were shown as a function of contact time, pH and initial chlorine concentration. Optimum contact time and removal pH value of MLP were determined as 2 hr and pH 10, respectively. Chlorine removal increased with increasing initial chlorine concentration up to 1.3g/L. Both Langmuir and Freundlich adsorption models were suitable for describing the short-term removal of chlorine by MLP and AC. According to Freundlich adsorption isotherms, the maximum removal capacity of MLP(0.264 mg Cl$_2$/mg) was nearly two times greater than that of AC(0.56 mg Cl$_2$/mg). These results suggested that MLP might potentially be used as an alternative to traditional water treatment materials for removal of residual chlorine in drinking water or process wastewater.

• 한국연초학회지
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• 제11권1호
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• pp.19-25
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• 1989

Effect of removal time of mulched polyethylene film on the chlorine content of toP soil and on the chlorine absorption by burley tobacco Plants was investigated under the field condition in 1986 and 1987. Treatment consisted of 4 removal times (from 30 to 75 days after transplanting with IS days interval) and control (no removal). The chlorine content of top Boll at 15 days after removal of mulched polyethylene film(MPF) lowered temporarily, and the decrement of chlorine content of top soil was closely related to the sum of rainfalls after removal of MPF. The chlorine was accumulated much in upper leaves when the MPF being removed early, while the chlorine was accumulated much in lower loaves when the MPF being removed late, relatively. However, the removal of MPF had no effect on the chlorine content of whole leaf. The yield decreased with removal of MPF during growing period.