• Journal of Soil and Groundwater Environment
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• v.7 no.3
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• pp.95-102
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• 2002

Manganese oxide/ hydrogen peroxide($MnO_2$/${H_2}{O_2}$) reactions were investigated as an alternative to Fenton-like reaction to reduce chlorinated organic compounds in groundwater This system showed high degradation of CT with low ${H_2}{O_2}$concentration($\leq$294mM) at neutral condition, and CT degradation increased with increasing pH values. The rate of CT degradation was not so much dependent on increase in $MnO_2$concentration since increase in production of oxygen during the reaction obstructed reaction of ${H_2}{O_2}$ on the surface of $MnO_2$. These results show that $MnO_2$catalyzed Ponton-like reaction could be a potential alternative method for treating chlorinated organic compounds in groundwater.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2011.10a
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• pp.261-262
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• 2011

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.261-266
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• 1997

가장 넓게 쓰이고 있는 알칼리염소법에 의한 도금폐수 처리법은 약 50년전에 Dodge와 Zabban에 의해 발표된 이론에 기초하고, 이것은 pH 및 ORP에 의존하는 반응으로 차아염소산이 시안화물을 시안산염으로 산화시키는 것이며, 알칼리조건하에서 염소화를 하는 동안에 시안화물이 파괴되고 중금속염은 침전을 생성한다. 이 반응은 1단계에서 시안산기가 바로 시안산나트륨으로 되는 것이 아니고 반응의 중간생성물인 염화시아노겐(CNCI)이라고 하는 독성물질이 생성되기 때문에 안전상의 문제가 있다. 또 알카리 염소법은 고농도일 경우에는 처리가 대단히 어렵고, 저농도일지라도 철, 니켈 및 구리와 같이 중금속성분이 다량 혼입되면 배출허용기준치이하로 처리하기는 사실상 불가능하다. (중략)

• Nuclear Engineering and Technology
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• v.29 no.6
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• pp.60-64
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• 1997

핵연료의 가공공정에서 발생하는 스러지를 건식처리공정으로 회수 정제할 수 있는 건식처리 방법에 대하여 논의하고자 하였다. 건식처리방법은 수용액을 전혀 사용하지 알기 때문에 폐기물의 발생량이 습식처리방법에 비해 훨씬 줄어든다. 산화우라늄은 고온의 용융염중에서 염소개스에 의해 염소화반응을 통하여 우라늄염화물을 생성되게 되어 이들은 전기적으로 이동이 가능한 형태로 바뀌므로 전극에 선택적으로 전착될 수 있기 때문에 다른 금속이온과 분리할 수 있다. 본 보고서에서는 산화우라늄의 염소화공정, 전착공정에 대하여 기술하였고 전착된 산화물의 물리적 특성에 대하여 요약하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.423-435
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• 2005

본 연구는 PVC를 포함한 혼합플라스틱을 연료화하는데 있어서 가장 큰 장애요인으로 되어있는 염소분을 효율적으로 제거하기 위한 목적으로 진행되었다. 염소성분을 원천적으로 제거하기 위해서는 PVC 내에 함유된 염소분을 제거하는 것이 관건이며 원천탈염을 통하여 제거하지 않으면 총괄 염소분의 변화가 없기 때문에 실제로 연료사용에는 한계가 있는 경우가 많다. 본 연구는 PVC중 56% 이상 함유되어 있는 염소성분을 연속식 스크루 반응기에 의하여 가열하여 제거하는 방식을 사용하였으며 각 공정의 변수별로 제거효율을 분석하여 최적조업조건에 대한 분석을 실시하였다. 일반적인 공정조업조건은 공급량, 혼합 플라스틱의 점도, 2차 반응기의 온도, 스크루 회전수 등이며 이 가운데 가장 결정적인 조건은 가열온도 변수이며 여타의 최적조업조건 하에서 $300^{\circ}C$ 이상인 경우에는 90% 이상의 탈염효율을 유지할 수 있음을 알 수 있었다.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1148-1152
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• 2008

Molten carbonate oxidation (MCO) is one of the promising alternative technologies for the treatment of the chlorinated organic compounds because it is capable of trapping chlorine during a destruction of them. In this study, destructions of chlorinated organic compounds ($C_6H_5Cl$, $C_2HCl_3$ and $CCl_4$) and an insulated oil containing PCBs were performed by using the two stage molten carbonate oxidation system. MCO reactor temperature largely affected the destruction of the chlorinated organic compounds. Destruction of the chlorinated organics very efficient in the primary MCO reactor however a significant amount of CO was emitted from the MCO system. This CO emission was gradually decreased by an increase in the primary reactor temperature and oxidizing air feed rate. The HCl emission from the MCO system was below 7 ppm regardless of tested conditions. The chlorine collection efficiencies were in the range of 99.95-99.99%. The destruction of PCBs in the insulated oil was efficient at a temperature above $900^{\circ}C$ and overall destruction efficiency of them was determined as over 99.9999%.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.173-176
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• 2012

Chlorine dioxide has an excellent ability to sterilize and deodorize and is harmless to humans. However, it is very unstable and explosive as it is highly concentrated, thus its use in the air clean filed has been limited. Therefore, there is a demand to develop the system to produce a low concentration of chlorine dioxide sustainedly. Here, for a first step in the development of the system on the sustained production of chlorine dioxide, the use of polymer hydrogels was investigated. P(MMA-co-HEMA) hydrogel particles were prepared via dispersion photopolymerization and sodium chlorite and citric acid were loaded respectively in the hydrogel particles. When sodium chlorite and citric acid were reacted with not loaded in the hydrogels, rapid production of chlorine dioxide occurred and the concentration of chlorine dioxide decreased over time. However, when sodium chlorite and citric acid were loaded respectively in the hydrogel particles and reacted, chlorine dioxide was produced slowly and sustainedly because the release of sodium chlorite and citric acid from the hydrogels delayed the reaction between them. The result shows that the use of P(MMA-co HEMA) hydrogels has the potential to develop the system on the sustained production of chlorine dioxide.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.115-119
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• 2005

As the regulations on DBPs are tightened, many water treatment plants (WTPs) in Korea have already introduced or will introduce enhanced coagulation, alternative disinfectants and advanced treatments such as ozonization and granular activated carbon to improve drinking water qualify. After a phenol leakage accident at the Nakdong-River in 1991, 26 WIPs in Korea introduced carbon dioxide generators, but there has been no accumulation of significant operating data. This research summarizes things that should be considered for the introduction of carbon dioxide disinfection process to WTPs based on one year operation data from A WTP that has had high concentration of DBP during a specific period in the summer. The removal efficiency of DBP was $30{\sim}40%$, but those of 2-MIB, Geosmin were less than 10%. The generation rate of $ClO_2$ by-products such as chlorite and chlorate were $70{\sim}100%$ of input dosage, but the ratios increased over time. At the same time, strong chlorine odors may be produced in the distribution system when $ClO_2$ was used with $Cl_2$ as a result of reaction between the chlorite and residual chlorine.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.627-634
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• 2009

This study was done to find out the formation mechanism of chlorate by electrochemical process using chloride ion ($Cl^-$) as an electrolyte. Firstly, the effective factors such as pH and initial chloride concentration were figured out to see the formation property of chlorate during electrolysis. And the relation of free chlorine, and mixed oxidants such as OH radical and ozone with chlorate were estimated to concretize the formation mechanism. As a result, it was found that the major reaction of chlorate formation would be electrochemical reaction with free chlorine, and also the direct oxidation of chloride ion and the reaction by OH radical were participated in the formation of chlorate. Moreover, it was observed that formed chlorate was oxidized to perchlorate. Lastly, the optimum condition was recommended by comparing free chlorine with chlorate concentration during the electrochemical process with the different electrode separation.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.569-577
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• 1996

pure compound chloromethanes; methyl chloride, methylene chloride, chloroform and The carbon tetrachloride were used as a model of chlorocarbon system with Cl/H ratio to investigate thermal stability and hydrodechlorination process of carbon tetrachloride under excess hydrogen atmosphere. The parent thermal stability on basis of temperature required for 99% destruction at 1 second no was evaluated as $875^{\circ}C$ for $CH_3Cl$, $780^{\circ}C$ for $CH_2Cl_2$, $675^{\circ}C$ for $CHCl_3$ and $635^{\circ}C$ for $CCl_4$. Chloroform was thermally less stable than $CCl_4$ at fairly low temperatures $(<570^{\circ}C).$ The lion of $CCl_4$ became more sensitive to increasing temperature, and $CCl_4$ was degraded CHCl3 at above $570^{\circ}C.$ The number and quantity of chlorinated products decreases with increasing temperature for the Product distribution of $CCl_4$ decomposition reaction system. Formation of non-chlorinated hydrocarbons such as $CH_4$, $C_2H_4$ and C_2H_6$ increased as the temperature rise and particularly small amount of methyl chloride was observed above $850^{\circ}C$ in $CC1_4$/$H_2$ reaction system. The less chlorinated products are more stable, with methyl chloride the most stable chlorocarbon in this reaction system.