• Title/Summary/Keyword: 염소

Search Result 1,873, Processing Time 0.129 seconds

A Study on the Chlorine-Exchange Reaction of Antimony Trichloride with Organic Chlorides (삼염화안티몬과 유기염소화합물 사이의 염소 교환반응에 관한 연구)

  • Yu, Seok Hwan;Bae, Yeong Il;Choe, Sang Eop
    • Journal of the Korean Chemical Society
    • /
    • v.34 no.1
    • /
    • pp.19-28
    • /
    • 1990
  • The rate of chlorine-exchange reaction of antimony trichloride with benzyl, $\alpha$-phenyl ethyl and diphenyl methyl chlorides in nitrobenzene have been determined. The results indicate that the chlorine-exchange reaction follows second-order kinetics with respect to antimony trichloride and first-order kinetics with respect to organic chlorides. Rate = $k_3[SbCl_3]^2$ [Org-Cl] The rate constants of chlorine-exchange of antimony trichloride with organic chloride increase in the following order of the organic chlorides. Benzyl chloride < $\alpha$-phenyl ethyl chloride < diphenyl methyl chloride The mechanism of the chlorine-exchange reactions has been proposed.

  • PDF

Development of Chloride Penetration Analysis Program Considering Environmental Conditions (환경조건을 고려한 염소이온 침투해석 프로그램 개발)

  • Kim, Ki Hyun;Jang, Seung Yup;Cha, Soo Won;Chang, Sung Pil
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.28 no.5A
    • /
    • pp.709-718
    • /
    • 2008
  • Developed is a chloride penetration analysis program in which changes of environmental conditions such as temperature, humidity and external chloride concentration, and the diffusion, convection and binding of chlorides are considered. In order to consider the changes of environmental conditions, analyses for temperature and moisture distribution are implemented simultaneously, and variation of diffusion coefficients due to temperature, humidity and age is also considered. By comparing the calculated total chloride contents with some experimental data, it has been confirmed that the proposed analysis program can trace measured chloride distribution well. Also, through some example analyses, the mechanism of accumulation of chlorides at near surface and acceleration of corrosion of steel reinforcement in case that the moisture distribution changes according to repeated drying and wetting cycles have been verified.

  • PDF

Mathematical Modeling of Re-Diffusion Response of De-Sorbed Chloride Ions in Concrete Due to Carbonation (콘크리트의 탄산화로 인해 탈착된 염소이온의 재확산에 대한 해석 연구)

  • Yoon, In-Seok;Sung, Jae-Duck
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2009.05a
    • /
    • pp.259-260
    • /
    • 2009
  • Many concrete structures have suffered from carbonation or chloride ion diffusion induced reinforcement corrosion, and a number of studies have been done on these topics. Many studies were mostly confined to the single deterioration of carbonation or chloride ion, although the environment actually presents a combined condition. This paper tried to develop the approach to compute re-diffusion of de-sorbed chloride due to carbonation of concrete. This is a key for successful combined deterioration model of carbonation and chloride. It is thought that this paper can contribute to express mathematically chloride enrichment and re-diffusion of chloride at front of carbonation.

  • PDF

Chloride Threshold Value for Steel Corrosion considering Chemical Properties of Concrete (콘크리트의 화학적 특성을 고려한 철근 부식 임계 염소이온 농도)

  • Song, Ha-Won;Jung, Min-Sun;Ann, Ki Yong;Lee, Chang-Hong
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.1A
    • /
    • pp.75-84
    • /
    • 2009
  • The present study assesses the chloride threshold level for corrosion of steel in concrete by examining the properties of four different binders used for blended concrete in terms of chloride binding, buffering of cement matrix to a pH fall and the corrosion behaviour. As binders, ordinary Portland cement (OPC), 30% pulverised fuel ash (PFA), 60% ground granulated blast furnace slag (GGBS) and 10% silica fume (SF) were used in a concrete mix. Testing for chloride binding was carried out using the water extraction method, the buffering of cement matrix was assessed by measuring the resistance to an artificial acidification of nitric acid, and the corrosion rate of steel in mortar with chlorides in cast was measured at 28 days using an anodic polarisation technique. Results show that the chloride binding capacity was much affected by $C_{3}A$ content and physical adsorption, and its order was 60% GGBS>30% PFA>OPC>10% SF. The buffering of cement matrix to a pH fall was varied with binder type and given values of the pH. From the result of corrosion test, it was found that the chloride threshold ranged 1.03, 0.65, 0.45 and 0.98% by weight of cement for OPC, 30% PFA, 60% GGBS and 10% SF respectively, assuming that corrosion starts at the corrosion rate of $0.1-0.2{\mu}A/cm^{2}$. The mole ratio of [$Cl^{-}$]:[$H^{+}$], as a new presentation of the chloride threshold, indicated the value of 0.008-0.009, irrespective of binder, which would be indicative of the inhibitive characteristic of binder.

  • PDF

The hydrodynamic dispersion characteristics of chloride in high permeable alluvial deposit at the Ttaan island, Kimhae city (김해시 딴섬의 고투수성 충적층에서 염소이온의 수리분산특성)

  • Kang, Dong-Hwan;Kim, Tae-Yeong;Yang, Sung-Il;Chung, Sang-Yong
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2007.05a
    • /
    • pp.707-711
    • /
    • 2007
  • 낙동강과 밀양강의 합류지점에 위치한 김해시 딴섬 지역의 지표면하 $25{\sim}35\;m$ 구간에 형성되어 있는 고투수성 충적층 내 염소이온의 수리분산특성을 연구하기 위한 수렴흐름 추적자시험(convergent flow tracer test)이 수행되었다. 추적자로는 IW-1공과 IW-2공에서 각각 염소이온 5kg이 순간주입(instantaneous injection) 되었으며, PW공에서 일정한 양수율(2,500 m3 /day)로 채수하면서 염소이온농도를 관측하였다. 염소이온 주입 후 경과시간에 따른 염소이온농도 자료를 이용하여 농도이력곡선과 누적질량회수곡선이 산출되었으며, 관측된 염소이온농도의 정규분포를 검증하기 위한 일반통계분석이 수행되었다. 그리고, 농도이력의 증가/감소 구간에서의 함수를 추정하였으며, 두 시험에서 동일한 시간에 관측된 염소이온농도의 상관성이 분석되었다. 본 현장에서 수행된 추적자시험에 의한 종분산지수의 추정은 CATTI 코드(Sauty and Kinzelbach, 1992)에 의해 해석되었다. 추정된 종분산지수는 IW-1공과 PW공 구간에서는 0.4152 m, IW-2공과 PW공 구간에서는 0.4158 m 로서 매우 유사한 값으로 나타났다. 이는 추적자시험이 수행된 충적층에서의 용질이송이 방사상으로 비교적 균일함을 의미하는 것이다. 본 연구에서 수행된 추적자시험의 규모(2 m)를 Xu and Eckstein(1995)이 제시한 방정식에 대입하여 산정된 종분산지수는 0.0458 m 이었다. 이러한 결과는, 본 연구지역에서 수렴흐름 추적자시험에 의해 추정된 고투수성 충적층의 종분산지수가 일반적인 자연대수층에 비해 9.1배 정도 높다는 것을 의미한다. 이는 시험대수층의 투수성이 매우 높아 염소이온의 용질이송이 매우 빠르게 발생되었기 때문이다. 본 연구에서 추정된 종분산지수를 Gelhar et al.(1992)의 연구 결과와 비교 분석한 결과에서도 시험규모에 비해 매우 높은 수리분산이 발생된 것으로 나타났다. 그리고 염소이온의 확산면적을 추정하기 위해, 수렴흐름 추적자시험에 의한 종분산지수와 시험대수층의 평균선형유속을 이용하여 종분산계수를 구하였다. 현장에서 수행된 양수시험에 의한 평균선형유속 22.44 m/day와 평균 종분산지수 0.4155 m를 적용하여 산정된 종분산계수는 $9.32\;m^2/day$이었다. 따라서, 시험부지 내 충적층에서 일정한 양수율$(2,500\;m^3/day)$로 지하수를 개발할 시에 양수정 주변지역으로 유입되는 염소이온의 확산면적은 1일 $9.32\;m^2$ 정도일 것으로 나타났다.

  • PDF

A Study on Chloride Binding Capacity of Various Blended Concretes at Early Age (초기재령에서 각종 혼합콘크리트의 염소이온 고정화능력에 관한 연구)

  • Song, Ha-Won;Lee, Chang-Hong;Lee, Kewn-Chu
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.12 no.5
    • /
    • pp.133-142
    • /
    • 2008
  • This paper studies the early-aged chloride binding capacity of various blended concretes including OPC(ordinary Portland cement), PFA(pulversied fly ash), GGBFS(ground granulated blast furnace slag) and SF(silica fume) cement paste. Cement pastes with 0.4 of a free water/binder ratio were cast with chloride admixed in mixing water, which ranged from 0.1 to 3.0% by weight of cement and different replacement ratios for the PFA, GGBFS and SF were used. The content of chloride in each paste was measured using water extraction method after 7 days curing. It was found that the chloride binding capacity strongly depends on binder type, replacement ratio and total chloride content. An increase in total chloride results in a decrease in the chloride binding, because of the restriction of the binding capacity of cement matrix. For the pastes containing maximum level of PFA(30%) and GGBFS(60%) replacement in this study, the chloride binding capacity was lower than those of OPC paste, and an increase in SF resulted in decreased chloride binding, which are ascribed to a latent hydration of pozzolanic materials and a fall in the pH of the pore solution, respectively. The chloride binding capacity at 7 days shows that the order of the resistance to chloride-induced corrosion is 30%PFA > 10%SF > 60%GGBFS > OPC, when chlorides are internally intruded in concrete. In addition, it is found that the binding behaviour of all binders are well described by both the Langmuir and Freundlich isotherms.

Efficacy of Chemical Sanitizers in Reducing Levels of Foodborne Pathogens and Formation of Chemically Injured Cells on Cabbage (양배추에 오염된 병원성 미생물의 저해 및 화학적 손상세포 생성에 있어서의 화학적 살균소독제의 효과)

  • Choi, Mi-Ran;Oh, Se-Wook;Lee, Sun-Young
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.37 no.10
    • /
    • pp.1337-1342
    • /
    • 2008
  • This study was conducted to investigate effects of chemical sanitizers on inhibiting foodborne pathogens, such as Listeria monocytogenes (L. monocytogenes), Salmonella Typhimurium (S. Typhimurium), and E scherichia coli O157:H7 (E. coli O157:H7), on cabbages. Cabbages were inoculated with the culture cocktail of pathogens and treated with water, 100 ppm commercial chlorine, and 50, 100, and 200 ppm chlorine dioxide ($ClO_2$) for 1, 5, and 10 min at room temperature ($22{\pm}2^{\circ}C$). Treatments with water did not significantly reduce levels of three pathogens whereas other treatments with chemical sanitizers significantly reduced levels of three pathogens. Treatment with 200 ppm $ClO_2$ for 10 min was the most effective at inhibiting pathogens and reduction levels were 1.90, 1.92, and 1.98 log CFU/g for L. monocytogens, S. Typhimurium, and E. coli O157:H7, respectively. Levels of reduction were increased with the increase of $ClO_2$ concentrations. When chemically injured cells were investigated, there were no significant differences on the levels of injured cells between before and after treatment with commercial chlorine and $ClO_2$. These results suggest that $ClO_2$ can be used as an alternative sanitizer for reducing pathogens on fresh produces.

Chlorosulfonated Polyethylene의 난연성 향상에 관한 연구( I )

  • Kim, Kyu-Baek;Lee, Chung;Shin, Hee-Kyung;Ryu, Boo-Hyung
    • Proceedings of the Korean Institute of Industrial Safety Conference
    • /
    • 1998.11a
    • /
    • pp.329-334
    • /
    • 1998
  • 난연성을 지닌 고분자 물질중 Chlorosulfonated Polyethylene(CSPE; Hypalon)은 Polyethylene에 염소와 황을 첨가한 것으로 염소를 첨가함으로써 기름과 화염에 대한 저항성을 향상시키고, 황 또한 기름, 화염에 대한 저항을 향상시킬 뿐 아니라 인장강도를 크게 해서 기계적 강도를 향상시킨 것이다. CSPE는 염소량의 등급에 따라 Coating재료, 호스 구조재, Wire와 Cable의 피복재료등 여러 가지 용도로 많이 쓰이고 있으며 특히 염소함량이 35%인 CSPE(Hypalon-40)의 경우 열저항과 압출 특성이 우수하기 때문에 Cable의 피복재료로 많이 쓰이고 있다.

  • PDF

Modeling of Chloride Ingress in Reinforced Concrete Structures (철근 콘크리트 구조물의 염소이온 침투 모델)

  • Koo, Hyun-Bon;Kim, Eui-Tae;Lee, Kwang-Myong
    • Journal of the Korea Concrete Institute
    • /
    • v.15 no.1
    • /
    • pp.25-34
    • /
    • 2003
  • The degradation of reinforced concrete (RC) structures due to physical and chemical attacks has been a major issue in construction engineering. Deterioration of RC structures by chloride attack followed by reinforcement corrosion is one of the serious problems. An objective of this study is to develop a form of mathematical model of chloride ingress into concrete. In order to overcome some limits of the previous approaches, a chloride ingress model, consisting of chloride solution intrusion through the capillary pore and chloride ion diffusion through the pore water, was proposed. Moreover, the variability of chloride ion diffusivity due to the degree of hydration of cement, relative humidity in pore, exposure condition, and variation of chloride binding, was considered in the model. In order to verify the proposed model, the results predicted by the proposed model were compared with analysis results of Life-365, a computer program for predicting the service life of reinforced concrete structures exposed to chlorides. In conclusion, the proposed model would be promising to predict the chloride ion profile and to estimate the service life of RC structures.

Removal of Geosmin by Combined Treatment of PAC and Intermediate Chlorination in the Conventional WTP (표준정수처리공정에서 분말활성탄과 중간염소를 이용한 지오스민 저감방안)

  • Kim, Tae Kyun;Choi, Jae Ho
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.37 no.1
    • /
    • pp.7-13
    • /
    • 2015
  • In this study, the effective treatment reducing geosmin and dosage of PAC was suggested when taste & odor compounds flow in. The removal efficiency of geosmin was evaluated with types of chlorination. In case of low geosmin concentration below 25 ng/L, removal efficiency of geosmin was estimated at 46% by combined treatment of pre and intermediate-chlorination. But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 57%. In the medium geosmin concentration (25~79 ng/L), removal efficiency of geosmin was estimated at 59% by combined treatment. But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 87%. When high geosmin concentration above 80 ng/L flows in, removal efficiency of geosmin was estimated at 69% by combined treatment. However, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 95%. Then, the exclusive intermediate-chlorination has an important effect on removal of geosmin. After correlation of geosmin concentration and dosage of PAC was analyzed, the coefficient of determination was estimated at 0.96. And, the proper PAC dosage chart was proposed. Also, at a initial occurrence of geosmin, when the combined treatment by intermediate-chlorination and PAC was applied, particle-bound geosmin should be removed continuously. Finally, it is proved that the combined treatment was effective to remove the geosmin by threshold levels as well as to reduce the dosage of PAC.