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Sample records for chlorine 46

  1. Chlorine

    Science.gov (United States)

    ... but it is also used to make pesticides (insect killers), rubber, and solvents. Chlorine is used in ... the following signs and symptoms may develop: Blurred vision Burning pain, redness, and blisters on the skin ...

  2. Chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL

    2009-01-01

    Following a brief description of the use of chlorine as a chemical warfare agent in World War I, this chapter summarizes physical and chemical data and recent clinical and controlled laboratory studies on the irritant and lethal effects of chlorine. The mechanism of toxicity for both irritation and lethal effects is described. The mathematical relationship between concentration and exposure duration for a set endpoint is given for both an irritancy response and mortality. This information can be used to assist in time-scaling for the set endpoint to other exposure durations. Risk assessment addresses the potential for greater effects in sensitive populations such as asthmatics. A concentration of 0.5 ppm for up to 8 hours is a no-adverse-effect concentration in most sensitive subjects; whereas, a concentration of 1.0 ppm induces some sensory irritation and transient changes in respiratory tract airflow parameters. Treatment and intervention of exposed individuals is dependent upon symptoms

  3. Influence of water chlorination on the counting of bacteria with DAPI (4',6-diamidino-2-phenylindole).

    Science.gov (United States)

    Saby, S; Sibille, I; Mathieu, L; Paquin, J L; Block, J C

    1997-01-01

    Counting bacteria in drinking water samples by the epifluorescence technique after 4',6-diamidino-2-phenylindole (DAPI) staining is complicated by the fact that bacterial fluorescence varies with exposure of the cells to sodium hypochlorite. An Escherichia coli laboratory-grown suspension treated with sodium hypochlorite (5 to 15 mg of chlorine liter-1) for 90 min was highly fluorescent after DAPI staining probably due to cell membrane permeation and better and DAPI diffusion. At chlorine concentrations greater than 25 mg liter-1, DAPI-stained bacteria had only a low fluorescence. Stronger chlorine doses altered the DNA structure, preventing the DAPI from complexing with the DNA. When calf thymus DNA was exposed to sodium hypochlorite (from 15 to 50 mg of chlorine liter-1 for 90 min), the DNA lost the ability to complex with DAPI. Exposure to monochloramine did not have a similar effect. Treatment of drinking water with sodium hypochlorite (about 0.5 mg of chlorine liter-1) caused a significant increase in the percentage of poorly fluorescent bacteria, from 5% in unchlorinated waters (40 samples), to 35 to 39% in chlorinated waters (40 samples). The presence of the poorly fluorescent bacteria could explain the underestimation of the real number of bacteria after DAPI staining. Microscopic counting of both poorly and highly fluorescent bacteria is essential under these conditions to obtain the total number of bacteria. A similar effect of chlorination on acridine orange-stained bacteria was observed in treated drinking waters. The presence of the poorly fluorescent bacteria after DAPI staining could be interpreted as a sign of dead cells. PMID:9097452

  4. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine…

  5. Chlorine Dioxide Gas Treatment of Cantaloupe and Residue Analysis

    OpenAIRE

    Kaur, Simran

    2013-01-01

    Chlorine dioxide is a selective oxidant and powerful antimicrobial agent. Previous work has shown that treatment of cantaloupe with chlorine dioxide gas at 5 mg/L for 10 minutes results in a 4.6 and 4.3 log reduction of E. coli O157:H7 and L. monocytogenes respectively. A significant reduction (p Current analytical methods for chlorine dioxide and chloroxyanions are only applicable to aqueous samples. Some of these methods have been used to determine surface residues in treated products by...

  6. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxi...

  7. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    OpenAIRE

    Taylor, Robert H; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains wer...

  8. Reaction products of chlorine dioxide.

    Science.gov (United States)

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxide treatment of organic materials are oxidized species, some of which also contain chlorine. The relative amounts of species types may depend on the amount of chlorine dioxide residual maintained and the concentration and nature of the organic material present in the source water. The trend toward lower concentrations of chlorinated by-products with increasing ClO2 concentration, which was observed with phenols, has not been observed with natural humic materials as measured by the organic halogen parameter. Organic halogen concentrations have been shown to increase with increasing chlorine dioxide dose, but are much lower than those observed when chlorine is applied. Aldehydes have been detected as apparent by-products of chlorine dioxide oxidation reactions in a surface water that is a drinking water source. Some other nonchlorinated products of chlorine dioxide treatment may be quinones and epoxides. The extent of formation of these moieties within the macromolecular humic structure is also still unknown. PMID:7151750

  9. Chlorine dioxide and hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.P. (Dartmouth Coll., Hanover, NH (USA). Dept. of Pharmacology and Toxicology)

    1989-05-01

    Because it has little or no tendency to generate carcinogenic trihalomethanes such as chloroform, chlorine dioxide is an attractive alternative to chlorine for drinking water disinfection. There are, however, concerns about its acute toxicity, and the toxic effects of its by-products, chlorite and chlorate. The human experience with chlorine dioxide in both controlled, prospective studies and in actual use situations in community water supplies have as yet failed to reveal adverse health effects. The EPA has recommended standards of 0.06 mg/L for chlorine dioxide and standards of 0.007 mg/L for chlorite and chlorate in drinking water. Among groups who may be at special risk from oxychlorines in drinking water are patients who must undergro chronic extracorporeal hemodialysis. Although even units for home hemodialysis are supposed to be equipped with devices which effectively remove oxychlorines, there is a always a possibility of operator error or equipment failure. When the equipment is adequately maintained, it is likely that dialysis patients will have more intensive exposures from drinking water than from dialysis fluids despite the much larger volumes of water that are involved in dialysis. This paper discusses a hemodialysis and the standards and effects of oxychlorines. 90 refs., 2 tabs.

  10. Reactions of aqueous chlorine and chlorine dioxide with model food compounds.

    OpenAIRE

    Fukayama, M Y; Tan, H; Wheeler, W B; Wei, C I

    1986-01-01

    Chlorine and chlorine dioxide (ClO2), common disinfecting and bleaching chemicals used in the food industry, are potent oxidizing and chlorinating agents. Unfortunately, little is known about the nature of the reactions of chlorine with organic food constituents. This presentation reviews published information concerning the reactions of chlorine gas (Cl2[g]), aqueous chlorine, and ClO2 with model food compounds, the fate of chlorine during the chlorination of specific food products, and the ...

  11. A comparison of chlorinated organic material produced by chlorine and chlorine dioxide bleaching

    Energy Technology Data Exchange (ETDEWEB)

    McKaque, A.B.; Reeve, D.W. [Univ. of Toronto (Canada)

    1995-12-31

    Chlorine and chlorine dioxide react differently with pulp during bleaching and produce different types of organic by-products. The main differences are the large reduction in the amount of AOX (adsorbable organic halogen) in the effluent and EOX (extractable organic halogen) in the pulp. This talk reviews the differences in the amounts and types of chlorinated organic by-products produced by the two different bleaching agents.

  12. Chlorine, Chloramine, Chlorine Dioxide, and Ozone Susceptibility of Mycobacterium avium

    Science.gov (United States)

    Taylor, Robert H.; Falkinham, Joseph O.; Norton, Cheryl D.; LeChevallier, Mark W.

    2000-01-01

    Environmental and patient isolates of Mycobacterium avium were resistant to chlorine, monochloramine, chlorine dioxide, and ozone. For chlorine, the product of the disinfectant concentration (in parts per million) and the time (in minutes) to 99.9% inactivation for five M. avium strains ranged from 51 to 204. Chlorine susceptibility of cells was the same in washed cultures containing aggregates and in reduced aggregate fractions lacking aggregates. Cells of the more slowly growing strains were more resistant to chlorine than were cells of the more rapidly growing strains. Water-grown cells were 10-fold more resistant than medium-grown cells. Disinfectant resistance may be one factor promoting the persistence of M. avium in drinking water. PMID:10742264

  13. Inactivation of Chironomid Larvae with Chlorine Dioxide and Chlorine

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-bin; CUI Fu-yi

    2008-01-01

    Chironomid larvae propagate prolifically in eutrophic water body and they cannot be exterminated by conventional disinfection process.The inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some boundary values in practice were determined under conditions of various oxidant dosage,organic precursor concentration and pH value.In addition,removal effect of differmt pre-oxidation combined with coagulation process on Chironomid larvae in law water was evaluated.It was found that chlorine dioxide possessed better inactivation effect than chlorine.Complete inactivation of Chironomid larvae in raw water was resulted by 1.5mg/L of chlorine dioxide with 30min of contact time. Additionally,the ocgallic precursor concentration,pH value had little influence on the inactivation effect.The coagulation jar test showed that Chironomid larvae in the raw water could be completely ronxwed by chlorine dioxide pre-oxidation in combination with the omgulation process at chlorine dioxide dosage of 0.8 mg/L.

  14. Gaseous, chlorine-free chlorine dioxide for drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, G. [Miami Univ., Oxford, OH (United States); Rosenblatt, A. [CDG Technology Inc., New York, NY (United States)

    1996-11-01

    The benefits of applying chlorine dioxide (ClO{sub 2}) for the oxidative treatment of drinking water are well established. Chlorine dioxide treated finished water typically has substantially lower trihalomethane (THM) levels because ClO{sub 2} will not form chlorinated organic species as a by-product of disinfection. The THMs that are formed are probably due to chlorine from the generator or chlorine used to maintain a post-disinfection residual. An emerging regulatory issue concerning the formation of disinfection by-products (DBPs) is causing the water industry to set standards for the generation and delivery of ClO{sub 2}. The Federal Register (11 February 1994) contains language developed to limit the production of the unwanted inorganic by-products chlorite (ClO{sub 2}{sup -}), chlorate (ClO{sub 3}{sup -}), and bromate (BrO{sub 3}{sup -}) ions by requiring utilities to maintain high (95%) generation efficiencies and by limiting the amount of excess Cl{sub 2} that can be used during the generation process. The efficiency and excess Cl{sub 2} regulations may be problematic for utilities that over-chlorinate to attain chlorine dioxide high yields. Many utilities will have to decide either to reduce the amount of Cl{sub 2} used to react with sodium chlorite (NaClO{sub 2}), thereby increasing the ClO{sub 2}{sup -} residual in finished water, or over-chlorinate to increase yields and surpass the excess Cl{sub 2} limits.

  15. Improved method generates more chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, R.W.; Kosinski, A.J.; Baker, R.J.

    1980-10-01

    The addition of acid can greatly improve the chlorine-chlorite process and enhance the use of chlorine dioxide as an alternative to chlorine for disinfection. The process is economical for use in taste and odor control, and for manganese, oxidation. The maximum yield is obtained using no excess chlorine, and the amount of unreacted sodium chlorite and chlorine in the product stream is reduced. (1 diagram, 4 graphs, 9 references)

  16. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  17. Transformation of iopamidol during chlorination.

    Science.gov (United States)

    Wendel, Friedrich M; Lütke Eversloh, Christian; Machek, Edward J; Duirk, Stephen E; Plewa, Michael J; Richardson, Susan D; Ternes, Thomas A

    2014-11-01

    The transformation of the iodinated X-ray contrast media (ICM) iopamidol, iopromide, iohexol, iomeprol, and diatrizoate was examined in purified water over the pH range from 6.5 to 8.5 in the presence of sodium hypochlorite, monochloramine, and chlorine dioxide. In the presence of aqueous chlorine, only iopamidol was transformed. All other ICM did not show significant reactivity, regardless of the oxidant used. Chlorination of iopamidol followed a second order reaction, with an observed rate constant of up to 0.87 M(-1) s(-1) (±0.021 M(-1) s(-1)) at pH 8.5. The hypochlorite anion was identified to be the reactive chlorine species. Iodine was released during the transformation of iopamidol, and was mainly oxidized to iodate. Only a small percentage (less than 2% after 24 h) was transformed to known organic iodinated disinfection byproducts (DBPs) of low molecular weight. Some of the iodine was still present in high-molecular weight DBPs. The chemical structures of these DBPs were elucidated via MSn fragmentation and NMR. Side chain cleavage was observed as well as the exchange of iodine by chlorine. An overall transformation pathway was proposed for the degradation of iopamidol. CHO cell chronic cytotoxicity tests indicate that chlorination of iopamidol generates a toxic mixture of high molecular weight DBPs (LC50 332 ng/μL).

  18. Cleaning without chlorinated solvents

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.M.; Simandl, R.F.

    1994-12-31

    Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

  19. Colorectal cancers and chlorinated water

    Institute of Scientific and Technical Information of China (English)

    Ahmed Mahmoud El-Tawil

    2016-01-01

    Published reports have revealed increased risk of colorectal cancers in people exposed to chlorinated drinking water or chemical derivatives of chlorination. Oestrogen plays a dual positive functions for diminishing the possibilities of such risk by reducing the entrance, and increasing the excretion, of these chemicals. In addition, there are supplementary measures that could be employed in order to reduce this risk further, such as boiling the drinking water, revising the standard concentrations of calcium, magnesium and iron in the public drinking water and prescribing oestrogen in susceptible individuals. Hypo-methylation of genomic DNA could be used as a biological marker for screening for the potential development of colorectal cancers.

  20. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    OpenAIRE

    Korich, D. G.; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactiv...

  1. Disinfectants: Chlorine and chlorine dioxide. (Latest citations from the Life Sciences Collection database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The bibliography contains citations concerning the antimicrobial properties of chlorine and chlorine dioxide. The use of chlorine for the inactivation of viruses, bacteria, and fungi in wastewater treatment plants is discussed, including the mode of action and factors influencing inactivation. The use of chlorine dioxide as an alternative to chlorine disinfection in swimming pools and water supplies, and possible adverse effects are also discussed. (Contains a minimum of 157 citations and includes a subject term index and title list.)

  2. Environmental factors regulating soil organic matter chlorination

    Science.gov (United States)

    Svensson, Teresia; Montelius, Malin; Reyier, Henrik; Rietz, Karolina; Karlsson, Susanne; Lindberg, Cecilia; Andersson, Malin; Danielsson, Åsa; Bastviken, David

    2016-04-01

    Natural chlorination of organic matter is common in soils. Despite the widespread abundance of soil chlorinated soil organic matter (SOM), frequently exceeding soil chloride abundance in surface soils, and a common ability of microorganisms to produce chlorinated SOM, we lack fundamental knowledge about dominating processes and organisms responsible for the chlorination. To take one step towards resolving the terrestrial chlorine (Cl) puzzle, this study aims to analyse how environmental factors influence chlorination of SOM. Four factors were chosen for this study: soil moisture (W), nitrogen (N), chloride (Cl) and organic matter quality (C). These factors are all known to be important for soil processes. Laboratory incubations with 36Cl as a Cl tracer were performed in a two soil incubation experiments. It was found that addition of chloride and nitrogen seem to hamper the chlorination. For the C treatment, on the other hand, the results show that chlorination is enhanced by increased availability of labile organic matter (glucose and maltose). Even higher chlorination was observed when nitrogen and water were added in combination with labile organic matter. The effect that more labile organic matter strongly stimulated the chlorination rates was confirmed by the second separate experiment. These results indicate that chlorination was not primarily a way to cut refractory organic matter into digestible molecules, representing one previous hypothesis, but is related with microbial metabolism in other ways that will be further discussed in our presentation.

  3. Effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Chlorine content and position of chlorinated phenols have many significant effects on the reactivity of oxido-reduction. The effects of chlorine content and position of chlorinated phenols on their oxidation kinetics by potassium permanganate were evaluated through different kinetics studies. Since chlorine was an electron withdrawing atom, the substitution of chlorine on the aromatic ring decreased the oxidation rate constant by σ-electron withdrawing conductive effect; at the same time, the substitution of chlorine at ortho or para position on the aromatic ring increased the oxidation rate constant by π-electron donating conjugative effect, and the conjugative effect could counteract the negative impact of the conductive effect to some extent. On the other hand, the substitution of chlorine at ortho position on the aromatic ring decreased the oxidation rate constant by steric hindrance effect. The oxidation rate constants of phenol and chlorinated phenols studied decreased as follow order: 4-chlorophenol>2,4-dichlorophenol>phenol>2,6-dichlorophenol.

  4. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method.

  5. Reactions of aqueous chlorine and chlorine dioxide with model food compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fukayama, M.Y.; Tan, H.; Wheeler, W.B.; Wei, C.

    1986-11-01

    This presentation reviews published information concerning the reactions of chlorine gas (CL/sub 2/(g)), aqueous chlorine, and ClO/sub 2/ with model food compounds, the fate of chlorine during the chlorination of specific food products, and the potential toxicity of the reaction products. Fatty acids and their methyl esters react with chlorine with the degree of incorporation corresponding to their degree of unsaturation. Aqueous chlorine oxidizes and chlorinates lipids and amino acids much more readily than ClO/sub 2/. Several amino acids are highly susceptible to oxidation and chlorination by chlorine compounds. Reactions of chlorine and ClO/sub 2/ with several food products, including flour and shrimp, have also been characterized. Although significant quantities of chlorine can be incorporated into specific model compounds and food products, the health risks associated with exposure to chlorinated organic products are unknown. Preliminary studies using the Ames Salmonella/microsome mutagenicity assay indicate that the reaction products from mixtures of aqueous chlorine and various lipids or tryptophan are nonmutagenic. Nevertheless, additional studies are warranted, so that the toxicological significance of these reaction products can be understood more fully.

  6. The effect of chlorine and combined chlorine/UV treatment on coliphages in drinking water disinfection.

    Science.gov (United States)

    Zyara, Alyaa M; Torvinen, Eila; Veijalainen, Anna-Maria; Heinonen-Tanski, Helvi

    2016-08-01

    Chlorine disinfection is a globally used method to ensure the safety of drinking water. However, it has not always been successful against viruses and, therefore, it is important to find new methods to disinfect water. Seventeen different coliphages were isolated from the treated municipal wastewater. These coliphages and MS2 were treated with different dosages of chlorine in drinking water, and a combined chlorine/ultraviolet irradiation treatment for the chlorine-resistant coliphages. Chlorine disinfection with 0.3-0.5 mg/L total chlorine (free Cl-dosage 0.12-0.21 mg/L) for 10 min achieved 2.5-5.7 Log10-reductions for 11 sensitive coliphages. The six most resistant coliphages showed no reduction with these chlorine concentrations. MS2 was intermediate in chlorine resistance, and thus it is not a good indicator for viruses in chlorine disinfection. In the combined treatment total chlorine of 0.05-0.25 mg/L (free Cl-dosage 0.02-0.08 mg/L) and ultraviolet irradiation (14-22 mWs/cm(2)) were more effective than chlorine alone, and 3-5 Log10-reductions were achieved for the chlorine-resistant strains. The chlorination efficiency could be increased by higher dosages and longer contact times, but this could increase the formation of disinfection by-products. Therefore, the combination treatment is a recommended disinfection method.

  7. Catalytic hydrogen-chlorine exchange between chlorinated hydrocarbons under oxygen-free conditions

    NARCIS (Netherlands)

    van der Heijden, A.W.A.M.; Podkolzin, S.G.; Jones, M.E.; Bitter, J.H.; Weckhuysen, B.M.

    2008-01-01

    Chlorinated hydrocarbons (CHCs) remain important industrial chemical intermediates and solvents, especially for the exploration of the potential of La-based materials for the conversion of chlorinated waste compounds.[1] The production of industrially important CHCs frequently occurs with concurrent

  8. Potassium chloride production by microcline chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, San Luis (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina)

    2015-08-10

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl{sub 2}–N{sub 2} mixture. • The chlorination generated KCl at 700 °C. • The chlorination products promote KCl formation. - Abstract: The potassium chloride is one of the most important fertilizers used in agriculture. The current demand of this salt makes interesting the study of potassium chloride production from unconventional potassium resources. In this work the potassium chloride production by chlorination of microcline was investigated. The starting reagents were microcline, hydromagnesite and chlorine. Non-isothermal and isothermal chlorination assays were carried out in a thermogravimetric device adapted to work in corrosive atmospheres. The temperature effect on potassium extraction and the phase transformations produced during chlorination of microcline were studied. The reagents and reaction products were analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD). The experimental results indicated that by chlorination of microcline an important extraction of potassium in the temperature range from 800 to 900 °C was produced. Moreover, at 800 °C the forsterite, enstatite and magnesium aluminate spinel phases were generated.

  9. The chlorination of cyclopentanone and cyclohexanone

    NARCIS (Netherlands)

    Maatman, Hendrik

    1980-01-01

    In this thesis the results of an investigation of the chlorination of cyclopentanone and cyclohexanone in the solvent carbontetrachloride and catalyzed by hydrogen chloride are described. ... Zie: Summary

  10. High resolution spectrophotometry for identification of chlorine dioxide in concentrated chlorine solutions.

    Science.gov (United States)

    Gauw, R D; Emmert, G L; Bubnis, B; Gordon, G

    1999-12-06

    Electrolyzed salt brine generators hold great promise for water disinfection in small communities and remote locations. Electrolysis cell liquors have been reported to contain chlorine, chlorine dioxide and ozone. High resolution spectrophotometry was used to observe the presence (or absence) of a unique spectral absorbance pattern present in solutions containing 1-2 mg/l chlorine dioxide.

  11. Inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine.

    OpenAIRE

    Berman, D; Hoff, J C

    1984-01-01

    The kinetics of inactivation of simian rotavirus SA11 by chlorine, chlorine dioxide, and monochloramine were studied at 5 degrees C with a purified preparation of single virions and a preparation of cell-associated virions. Inactivation of the virus preparations with chlorine and chlorine dioxide was studied at pH 6 and 10. The monochloramine studies were done at pH 8. With 0.5 mg of chlorine per liter at pH 6, more than 4 logs (99.99%) of the single virions were inactivated in less than 15 s...

  12. The photoreactivity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vaida, V. [Univ. of Colorado, Boulder, CO (United States); Simon, J.D. [Univ. of California, San Diego, La Jolla, CA (United States)

    1995-06-09

    Determining the detailed photoreactivity of radicals that are of importance in atmospheric processes requires information from both laboratory and field measurements and theoretical calculations. Laboratory experiments and quantum calculations have been used to develop a comprehensive understanding of the photoreactivity of chlorine dioxide (OClO). The photoreactivity is strongly dependent on the medium (gas phase, liquid solution, or cryogenic matrix). These data reveal details of the complex chemistry of OClO. The potential role of this radical in stratospheric ozone depletion is discussed in accord with these laboratory measurements. 53 refs., 4 figs.

  13. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability

    Energy Technology Data Exchange (ETDEWEB)

    Korich, D.G.; Mead, J.R.; Madore, M.S.; Sinclair, N.A.; Sterling, C.R. (Univ. of Arizona, Tucson (USA))

    1990-05-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water.

  14. Effects of ozone, chlorine dioxide, chlorine, and monochloramine on Cryptosporidium parvum oocyst viability.

    Science.gov (United States)

    Korich, D G; Mead, J R; Madore, M S; Sinclair, N A; Sterling, C R

    1990-01-01

    Purified Cryptosporidium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were comparatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlorine and monochloramine did. Greater than 90% inactivation as measured by infectivity was achieved by treating oocysts with 1 ppm of ozone (1 mg/liter) for 5 min. Exposure to 1.3 ppm of chlorine dioxide yielded 90% inactivation after 1 h, while 80 ppm of chlorine and 80 ppm of monochloramine required approximately 90 min for 90% inactivation. The data indicate that C. parvum oocysts are 30 times more resistant to ozone and 14 times more resistant to chlorine dioxide than Giardia cysts exposed to these disinfectants under the same conditions. With the possible exception of ozone, the use of disinfectants alone should not be expected to inactivate C. parvum oocysts in drinking water. PMID:2339894

  15. Mutagenic compounds from chlorination of humic substances

    Science.gov (United States)

    Holmbom, Bjarne

    Chlorination of natural humic substances, as well as of lignin, produces a myriad of non-chlorinated and chlorinated compounds. The identification of an important class of strongly mutagenic compounds is reviewed. The most important Ames mutagen in chlorinated drinking waters of various origin is the compound 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone ("MX"). This compound occurs at neutral pH in the acyclic form, i.e. in the form of Z-2-chloro-3-(dichloromethyl)-4-oxobutenoic acid. Its E-isomer (E-MX) is present in chlorinated drinking waters at a similar concentration, but is less mutagenic in Ames test. Both oxidised and reduced forms of MX and E-MX are also present in chlorinated waters. The present knowledge of the chemistry and toxicology of these mutagens is examined. The formation and possible elimination of the chlorination mutagens is discussed. The need of understanding the mechanisms of formation of these mutagens from humic substances during drinking water chlorination is emphasized.

  16. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald

    1968-01-01

    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  17. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    1998-12-31

    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  18. Chlorination of Wastewater, Manual of Practice No. 4.

    Science.gov (United States)

    Water Pollution Control Federation, Washington, DC.

    This manual reviews chlorination practices in the treatment and disposal of wastes from the earliest known applications. The application of chlorination for various purposes is described but no attempt has been made to compare chlorination with other methods. Included are chapters on the development and practice of wastewater chlorination,…

  19. Electron affinity of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Babcock, L.M.; Pentecost, T.; Koppenol, W.H. (Louisiana State Univ., Baton Rouge (USA))

    1989-12-14

    The flowing afterglow technique was used to determine the electron affinity of chlorine dioxide. A value of 2.37 {plus minus} 0.10 eV was found by bracketing between the electron affinities of HS* and SF{sub 4} as a lower limit and that of NO{sub 2} as an upper limit. This value is in excellent agreement with 2.32 eV predicted from a simple thermodynamic cycle involving the reduction potential of the ClO{sub 2}/ClO{sub 2}{sup {minus}} couple and a Gibbs hydration energy identical with that of SO{sub 2}{sup {sm bullet}{minus}}.

  20. Phosphate valorization by dry chlorination route

    OpenAIRE

    Kanari N.; Menad N.; Diot F.; Allain E.; Yvon J.

    2016-01-01

    International audience; This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca 2 P 2 O 7), is subjected to reactions with Cl 2 +CO+N 2 and Cl 2 +C+N 2 at temperatures ranging from 625 to 950 °C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM ...

  1. Efficacy and Safety Evaluation of a Chlorine Dioxide Solution

    Directory of Open Access Journals (Sweden)

    Jui-Wen Ma

    2017-03-01

    Full Text Available In this study, a chlorine dioxide solution (UC-1 composed of chlorine dioxide was produced using an electrolytic method and subsequently purified using a membrane. UC-1 was determined to contain 2000 ppm of gaseous chlorine dioxide in water. The efficacy and safety of UC-1 were evaluated. The antimicrobial activity was more than 98.2% reduction when UC-1 concentrations were 5 and 20 ppm for bacteria and fungi, respectively. The half maximal inhibitory concentrations (IC50 of H1N1, influenza virus B/TW/71718/04, and EV71 were 84.65 ± 0.64, 95.91 ± 11.61, and 46.39 ± 1.97 ppm, respectively. A 3-(4,5-Dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT test revealed that the cell viability of mouse lung fibroblast L929 cells was 93.7% at a 200 ppm UC-1 concentration that is over that anticipated in routine use. Moreover, 50 ppm UC-1 showed no significant symptoms in a rabbit ocular irritation test. In an inhalation toxicity test, treatment with 20 ppm UC-1 for 24 h showed no abnormality and no mortality in clinical symptoms and normal functioning of the lung and other organs. A ClO2 concentration of up to 40 ppm in drinking water did not show any toxicity in a subchronic oral toxicity test. Herein, UC-1 showed favorable disinfection activity and a higher safety profile tendency than in previous reports.

  2. Efficacy and Safety Evaluation of a Chlorine Dioxide Solution

    Science.gov (United States)

    Ma, Jui-Wen; Huang, Bin-Syuan; Hsu, Chu-Wei; Peng, Chun-Wei; Cheng, Ming-Long; Kao, Jung-Yie; Way, Tzong-Der; Yin, Hao-Chang; Wang, Shan-Shue

    2017-01-01

    In this study, a chlorine dioxide solution (UC-1) composed of chlorine dioxide was produced using an electrolytic method and subsequently purified using a membrane. UC-1 was determined to contain 2000 ppm of gaseous chlorine dioxide in water. The efficacy and safety of UC-1 were evaluated. The antimicrobial activity was more than 98.2% reduction when UC-1 concentrations were 5 and 20 ppm for bacteria and fungi, respectively. The half maximal inhibitory concentrations (IC50) of H1N1, influenza virus B/TW/71718/04, and EV71 were 84.65 ± 0.64, 95.91 ± 11.61, and 46.39 ± 1.97 ppm, respectively. A 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test revealed that the cell viability of mouse lung fibroblast L929 cells was 93.7% at a 200 ppm UC-1 concentration that is over that anticipated in routine use. Moreover, 50 ppm UC-1 showed no significant symptoms in a rabbit ocular irritation test. In an inhalation toxicity test, treatment with 20 ppm UC-1 for 24 h showed no abnormality and no mortality in clinical symptoms and normal functioning of the lung and other organs. A ClO2 concentration of up to 40 ppm in drinking water did not show any toxicity in a subchronic oral toxicity test. Herein, UC-1 showed favorable disinfection activity and a higher safety profile tendency than in previous reports. PMID:28327506

  3. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G. R.; Butler, M.

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  4. Behavior of chlorine during coal pyrolysis

    Science.gov (United States)

    Shao, D.; Hutchinson, E.J.; Cao, H.; Pan, W.-P.; Chou, C.-L.

    1994-01-01

    The behavior of chlorine in Illinois coals during pyrolysis was evaluated by combined thermo-gravimetry-Fourier transform infrared spectroscopy-ion chromatography (TG-FTIR-IC) techniques. It was found that more than 90% of chlorine in Illinois coals (IBC-103, 105, 106, and 109) was liberated as HCl gas during pyrolysis from 300 to 600??C, with the rate reaching a maximum at 440 ??C. Similarity of the HCl and NH3 release profiles during pyrolysis of IBC-109 supports the hypothesis that the chlorine in coal may be associated with nitrogen and the chlorine is probably bonded to the basic nitrogen sites on the inner walls of coal micropores. ?? 1994 American Chemical Society.

  5. Chlorine Salts at the Phoenix Landing Site

    Science.gov (United States)

    Hanley, J.; Horgan, B.

    2016-09-01

    Although chlorine salts (perchlorates, chlorides) are known to exist at the Phoenix landing site, their distribution and type have not been positively identified yet. We look for these salts through a novel NIR remote sensing technique.

  6. Hydrochloric acid recycling from chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Sowieja, D. [Sulzer Escher Wyss GmbH, Ravensburg (Germany); Schaub, M. [Sulzer Chemtech Ltd., Winterthur (Switzerland)

    1993-12-31

    Chlorinated hydrocarbons present a major ecological hazard since most of them are only poorly biodegradable. Incineration is an economical process for their destruction, however the usually recovered sodium or calcium chlorides do not present a value and their disposal may even be very costly. Recovery of hydrochloric acid may therefore present an economical solution, mainly were large quantities of highly chlorinated compounds can be processed (author) 6 refs., 4 figs., 1 tab.

  7. Modeling Trihalomethane Formation Potential from Wastewater Chlorination

    Science.gov (United States)

    1994-09-01

    chemically with each other, and with living organisms, particularly bacteria ( Manahan , 1991:435). To ensure effective disinfection, to meet the CWA...halogens are strong oxidants and are highly reactive ( Manahan , 1991:504). Chlorine is never found uncombined in nature, it exists only as the...HOCI) according to the following reaction: Cl2 (gas) + H20 =• HOC1 + H+ + Cl The hydrogen is oxidized and the chlorine gas is reduced ( Manahan , 1991

  8. Chlorinated drinking water for lightweight laying hens

    Directory of Open Access Journals (Sweden)

    A.F. Schneider

    Full Text Available ABSTRACT The study aimed to evaluate the effect of different levels of chlorine in drinking water of laying hens on zootechnical performance, eggs shell quality, hemogasometry levels and calcium content in tibia. 144 Hy-Line laying hens, 61 weeks old, were used distributed in 24 metabolism cages. They were subjected to water diets, for a period of 28 days, using sodium hypochlorite as a chlorine source in order to obtain the following concentrations: 5ppm (control, 20ppm, 50ppm, and 100ppm. Their performance was evaluated through water consumption, feed intake, egg production and weight, egg mass, feed conversion. Shell quality was measured by specific gravity. At the end of the experiment, arterial blood was collected for blood gas level assessment and a poultry of each replicate was sacrificed to obtain tibia and calcium content measurement. There was a water consumption reduction from 20ppm of chlorine and feed intake reduction in poultry receiving water with 100ppm of chlorine. The regression analysis showed that the higher the level of chlorine in water, the higher the reduction in consumption. There were no differences in egg production and weight, egg mass, feed conversion, specific gravity, tibia calcium content, and hemogasometry levels (hydrogenionic potential, carbon dioxide partial pressure, oxygen partial pressure, sodium, potassium, chloride, bicarbonate, carbon dioxide total concentration, anion gap and oxygen saturation. The use of levels above 5ppm of chlorine is not recommended in the water of lightweight laying hens.

  9. A new kind of Molotov? Gasoline-pool chlorinator mixtures.

    Science.gov (United States)

    Hutches, Katherine; Lord, James

    2012-07-01

    This paper investigates the reaction between pool chlorinators and gasoline. In particular, the propensity for self-ignition and the resulting chemical products were studied. An organic pool chlorinator was combined with gasoline in varying proportions in an attempt to form a hypergolic mixture. None of the combinations resulted in self-ignition, but larger quantities of chlorinator produced vigorous light-colored smoke and a solid mass containing isocyanuric acid and copper chloride. Additionally, the chlorinating abilities of different commercially available pool chlorinators were explored. When Ca(ClO)(2) and sodium dichloro-s-triazinetrione-based chlorinators were used, the presence of gasoline was still visible after 10 days, despite limited chlorination. The trichloro-s-triazinetrione-based chlorinator, however, caused efficient chlorination of the C(2)- and C(3)-alkylbenzenes, making gasoline no longer identifiable.

  10. Maxillofacial prostheses of chlorinated polyethylene.

    Science.gov (United States)

    May, P D

    1978-05-01

    There is clearly a need for maxillofacial prosthetic materials with improved properties. The chlorinated polyethylenes are thermoplastic elastomers which have particularly promising properties, and were used by us to prepare improved maxillofacial prostheses. Suitable CPE resins were compounded with other polymers and with pigments on a heated rubber mill to form thin sheets in a variety of shades. These were heated at 190 degrees C for 10 min and placed between heated linotype mold halves. The prosthesis was formed in a hand press. Sometimes heating and pressing were repeated. After cooling in water, the prosthesis was removed and hand-shaded with oil-soluble dyes. Physical properties were evaluated using standard techniques; skin irritation studies were conducted by 14-day insult patch tests on rabbits. Clinical evaluations were conducted on human volunteers. Parallel evaluations were conducted on commerically available materials for comparison. The CPE was superior to all of the three commerical materials in most properties, and comparable to the better of the three in the remaining properties. On balance, CPE was significantly superior. Early results indicate that the materials and techniques required are easily handled in the dental lab and that the final prosthesis has excellent aesthetic and patient acceptability.

  11. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

    Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\\mu$m. The high resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4m telescope. The average [$^{35}$Cl/Fe] abundance in stars with --0.72$<$[Fe/H]$<$0.20 is [$^{35}$Cl/Fe]=(--0.10$\\pm$0.15) dex. The mean difference between the [$^{35}$Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16$\\pm$0.15) dex. The [$^{35}$Cl/Ca] ratio has an offset of $\\sim$0.35 dex above model predictions suggesting chemical evolution models are under producing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and \\ion{H}{2} regions. In one star where both H$^{35}$Cl a...

  12. Reactions of polynuclear aromatic hydrocarbons with chlorine and chlorine dioxide in coal tar lined pipes

    Energy Technology Data Exchange (ETDEWEB)

    Merkel, T.; Maier, M.; Sacher, F.; Maier, D. [University of Karlsruhe, Karlsruhe (Germany). Engler Bunte Institut

    1997-12-31

    In the presence of disinfectants, PAH are remobilised from the coal tar lining of water distribution mains. Reactions of the PAH with chlorine and chlorine dioxide can lead to chlorinated PAH that might show higher mutagenic effects that the parent PAH. Detection limits in the lower nanogram-per-litre level for the determination of PAH and chlorinated PAH were achieved by using solid phase micro extraction and a gas chromatographic mass spectrometric device. Thus, the reactions of four PAH (anthracene, fluoranthene, fluorene and phenanthrene) with chlorine and chlorine dioxide under conditions and at concentrations of common practice in the drinking water distribution system could be investigated. In batch experiments with demineralised and drinking water at pH 7, the concentrations of fluoranthene, fluorene and phenanthrene remained constant, whereas anthracene reacted quantitatively with both disinfectants. The reaction of anthracene followed by pseudo-first order kinetics. In these reactions no chlorinated products could be detected, only monohydroxyanthracene and anthraquinone were identified. The toxic effect of a set of chlorinated and oxidised PAH was also examined.

  13. Bromate ion formation in dark chlorination and ultraviolet/chlorination processes for bromide-containing water

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Bormate (BrO3-) is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions,particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet (UV)/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards (10 μg/L). UV irradiation enhanced the decay of free chlorine, and,simultaneously, 6.6%-32% of Br- was oxidized to BrO3-. And the formation of bromate exhibited three stages: rapid stage, slow stage and plateau. Under the experimental conditions (pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L), low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.

  14. Chlorine dioxide treatment for zebra mussel control

    Energy Technology Data Exchange (ETDEWEB)

    Rybarik, D. [Dairyland Power Cooperative, La Crosse, WI (United States); Byron, J. [Nalco Chemical Company, Naperville, IL (United States); Germer, M. [Rio Linda Chemical Company, Sacramento, CA (United States)

    1995-06-01

    Chlorine is recognized and commonly used biocide for power plant cooling water and service water treatment programs, including the control of zebra mussels. Chlorine dioxide has recently become a popular method of zebra mussel control because of its economy, safety, environmental acceptability, and effectiveness when compared to other mussel control methods. This control technique was recently demonstrated at Dairyland Power Cooperative`s Alma Generating Station on the east bank of the upper Mississippi River in Alma, Wisconsin. The project was assisted with EPRI Tailored Collaboration Program funds. The Dairyland Power Alam Generating Station consists of five generating units that utilize raw, untreated Mississippi River water for condenser, circulating, and service water supplies. The first units were built in 1947, with the final and largest unit being completed in 1960. Total station generating capacity is 200 MW. Because of recent increases in the zebra mussel density at the station intake, Dairyland Power selected the team of Nalco and Rio Linda to perform a chlorine dioxide treatment of the station`s new water systems to eradicate and control the mussels before their presence created operational difficulties. This paper will present the results of the treatment including treatment theory, design and construction of the treatment system, the method of chlorine dioxide generation, treatment concentration, analytical methods o monitoring chlorine dioxide generation, residuals and trihalomethane (THM) concentrations, protocol for monitoring treatment mortality, and the effects of chlorine dioxide and detoxification on other water chemistry parameters and equipment materials. The goal of this paper is to inform and assist users with establishing consistent and uniform practices for safely utilizing and monitoring chlorine dioxide in the eradication and control of zebra mussels.

  15. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

    Owing to its low cost,free chlorine is one of the most common disinfectants for wastewater and drinking water treatment.However,the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades.Antipyrine (ANT),an anti-inflammatory analgesic,has been frequently detected in the aquatic environment.In this work.the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments.The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L,free chlorine dosage from 0.30 to 1.31 mg/L,and pH from 1.5 to 9.0.The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry.The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L,ANT 0.5 mg/L,pH 7.0).Higher oxidant dosage,lower ANT initial concentration and low pH favor the ANT removal.The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-l,2-dihydro1,5-dimethyl-2-phenyl-3H-pyrazol-3-one),which can be further chlorinated by free chlorine.In addition,the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  16. Influencing factors and degradation products of antipyrine chlorination in water with free chlorine.

    Science.gov (United States)

    Cai, Meiquan; Zhang, Liqiu; Qi, Fei; Feng, Li

    2013-01-01

    Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.

  17. Effect of chlorination on the development of marine biofilms dominated by diatoms

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Jagadeesan, V.

    , and Thalassionema did not increase in density after chlorine treatment. It was also demonstrated that diatoms can colonize, grow and photosynthesize on chlorine-treated surfaces. Under pulse chlorination (treatment every 6 h), irrespective of chlorine concentration...

  18. Chlorination of organophosphorus pesticides in natural waters.

    Science.gov (United States)

    Acero, Juan L; Benítez, F Javier; Real, Francisco J; González, Manuel

    2008-05-01

    Unknown second-order rate constants for the reactions of three organophosphorus pesticides (chlorpyrifos, chlorfenvinfos and diazinon) with chlorine were determined in the present study, and the influence of pH and temperature was established. It was found that an increase in the pH provides a negative effect on the pesticides degradation rates. Apparent second-order rate constants at 20 degrees C and pH 7 were determined to be 110.9, 0.004 and 191.6 M(-1) s(-1) for chlorpyrifos, chlorfenvinfos and diazinon, respectively. A higher reactivity of chlorine with the phosphorothioate group (chlorpyrifos and diazinon) than with the phosphate moiety (chlorfenvinfos) could explain these results. Intrinsic rate constant for the elementary reactions of chlorine species with chlorpyrifos and diazinon were also calculated, leading to the conclusion that the reaction between hypochlorous acid and the pesticide is predominant at neutral pH. The elimination of these pesticides in surface waters was also investigated. A chlorine dose of 2.5 mg L(-1) was enough to oxidize chlorpyrifos and diazinon almost completely, with a formation of trihalomethanes below the EU standard for drinking water. However, the removal of chlorfenvinfos was not appreciable. Therefore, chlorination is a feasible option for the removal of organophosphorus pesticides with phosphorothioate group during oxidation and disinfection processes, but not for the elimination of pesticides with phosphate moiety.

  19. The effects of low level chlorination and chlorine dioxide on biofouling control in a once-through service water system

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, W.E. Jr. [Alabama Power Co./GSC No. 8, Birmingham, AL (United States); Laylor, M.M. [Univ. of Alabama, Birmingham, AL (United States)

    1995-06-01

    Continuous chlorination has been successfully used for the control of Corbicula at a nuclear power plant located on the Chattahoochee River in southeastern Alabama, since 1986. The purpose of this study was to investigate further minimization of chlorine usage and determine if chlorine dioxide is a feasible alternative. Four continuous biocide treatments were evaluated for macro and microfouling control effectiveness, operational feasibility, and environmental acceptability. One semi-continuous chlorination treatment was also evaluated for macrofouling control effectiveness. Higher treatment residuals were possible with chlorine dioxide than with chlorination due to the river discharge limitations. At the levels tested, continuous chlorine dioxide was significantly more effective in providing both macro and microfouling control. Semi-continuous chlorination was just as effective as continuous chlorination for controlling macrofouling. The Corbicula treatment programs that were tested should all provide sufficient control for zebra mussels. Chlorine dioxide was not as cost effective as chlorination for providing macrofouling control. The semi-continuous treatment save 50% on chemical usage and will allow for the simultaneous treatment of two service water systems. Chlorite levels produced during the chlorine dioxide treatments were found to be environmentally acceptable. Levels of trihalomethanes in the chlorinated service water were less than the maximum levels allowed in drinking water.

  20. Microbiological aspects of the removal of chlorinated hydrocarbons from air

    NARCIS (Netherlands)

    Dolfing, Jan; Wijngaard, Arjan J. van den; Janssen, Dick B.

    1993-01-01

    Chlorinated hydrocarbons are widely used synthetic chemicals that are frequently present in industrial emissions. Bacterial degradation has been demonstrated for several components of this class of compounds. Structural features that affect the degradability include the number of chlorine atoms and

  1. Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

    DEFF Research Database (Denmark)

    Morales-Suárez-Varela, Maria M; Olsen, Jørn; Villeneuve, Sara;

    2013-01-01

    To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF).......To evaluate the potential association between occupational exposure to chlorinated and petroleum solvents and mycosis fungoides (MF)....

  2. Identification of intermediates leading to chloroform and C-4 diacids in the chlorination of humic acid

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leer, E.W.B. de; Erkelens, Corrie; Galan, L.

    1985-01-01

    The chlorination of terrestrial humic acid was studied at pH 7. 2 with varying chlorine to carbon ratios. The principal products are chloroform, di- and trichloroacetic acid, and chlorinated C-4 diacids. At a high chlorine dose many new chlorination products were detected, among them chlorinated aro

  3. Diurnal variation of stratospheric chlorine monoxide - A critical test of chlorine chemistry in the ozone layer

    Science.gov (United States)

    Solomon, P. M.; De Zafra, R.; Parrish, A.; Barrett, J. W.

    1984-01-01

    Ground-based observations of a mm-wave spectral line at 278 GHz have yielded stratospheric chlorine monoxide column density diurnal variation records which indicate that the mixing ratio and column density of this compound above 30 km are about 20 percent lower than model predictions based on 2.1 parts/billion of total stratospheric chlorine. The observed day-to-night variation is, however, in good agreement with recent model predictions, both confirming the existence of a nighttime reservoir for chlorine and verifying the predicted general rate of its storage and retrieval.

  4. Chlorine: Undergraduate Research on an Element of Controversy

    Science.gov (United States)

    Chang, Hasok

    2009-04-01

    If chemical elements were people, chlorine would be a celebrity. Although intrinsically no more or less important than any other element, chlorine has had a knack of making headlines. The genre of "object biography" has been quite successful in popular science recently. We took this opportunity to write a "biographical" study of chlorine. Chlorine's wide range of interesting controversies is well suited for attracting and maintaining the enthusiasm of the diverse range of students we teach in our department.

  5. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  6. Chlorination of nickel ore by gaseous chlorine in the presence of active additives

    Directory of Open Access Journals (Sweden)

    Ilić Ilija B.

    2003-01-01

    Full Text Available Paper presents a thermodynamic analysis of chemical reactions occurring during chlorination with and without additives for both nickel oxides and nickel ferrites, which are component parts of nickel ore. The experimental research investigated the influence of temperature in the range from 600 up to 1000 °C and time (up to 3 h on the chlorination degree of nickel ores with and without additives. It was found that the introduction of additives such as C, S, BaS and NaCl intensified the chlorination of nickel ore. The results can be applied and may help determine the optimal conditions for the chlorination of low-grade ferrous nickel ores.

  7. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    OpenAIRE

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested o...

  8. Chlorinated organic compounds in urban river sediments

    Energy Technology Data Exchange (ETDEWEB)

    Soma, Y.; Shiraishi, H.; Inaba, K. [National Inst. of Environmental Studies, Tsukuba, Ibaraki (Japan)

    1995-12-31

    Among anthropogenic chemicals, many chlorinated organic compounds have been used as insecticides and detected frequently as contaminants in urban river sediments so far. However, the number and total amount of chemicals produced commercially and used are increasing year by year, though each amount of chemicals is not so high. New types of contaminants in the environment may be detected by the use of newly developed chemicals. Chlorinated organic compounds in the urban river sediments around Tokyo and Kyoto, large cities in Japan, were surveyed and recent trends of contaminants were studied. Contaminants of the river sediments in industrial areas had a variety, but PCB (polychlorinated biphenyls) was detected in common in industrial areas. Concentration of PCB related well to the number of factories on both sides of rivers, although the use of PCB was stopped 20 years ago. In domestic areas, Triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol) and Triclocarban (3,4,4{prime}-trichlorocarbanilide)(both are contained in soap or shampoo for fungicides), p-dichlorobenzene (insecticides for wears) and TCEP(tris-chloroethyl phosphate) were detected. EOX(extracted organic halogen) in the sediments was 5 to 10 times of chlorinated organic compounds detected by GC/MS. Major part of organic halogen was suggested to be included in chlorinated organics formed by bleaching or sterilization.

  9. Method and apparatus for producing chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Santillie, P.W.; Ramras, D.M.

    1984-05-29

    A continuous method and apparatus are described for the efficient production of gaseous chlorine dioxide by the reaction between gaseous sulfur dioxide and an aqueous solution of a metallic chlorate. The chlorate solution and a highly concentrated sulfur dioxide gas are introduced into a packed columnar chamber at closely adjacent locations at the bottom of the chamber so as to flood the chamber and maximize both the contact area and contact time of the two reactants. Throughout the reaction the chamber is subjected to high vacuum imposed by an eductor which exhausts the chlorine dioxide gas and spent reactants. For use of the chlorine dioxide to produce potable water or treat foodstuffs, the chlorine dioxide and spent reactants are exhausted from the chamber separately by respective eductors substantially balanced with respect to each other to impose comparable vacuums upon the chamber. Because of the high efficency of the reaction, substantial heat is generated therefrom which is absorbed by a coolant flowing through a jacket surrounding the chamber. The flow rate of the coolant and flow rate of the reactants into the chamber are porportional due to the dependency of the reactant flow rate on the coolant flow rate.

  10. Photoabsorption and photoionization of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Flesch, R.; Ruehl, E.; Hottmann, K.; Baumgaertel, H. (Freie Universitaet Berlin (Germany))

    1993-01-28

    Photoprocesses of chlorine dioxide in the near-UV have become highly important for stratospheric photoprocesses at high latitudes, especially in Antarctica. Chlorine dioxide has been identified among other absorbers because of its specific absorption cross section in the near-UV. Possible contributions of chlorine dioxide photochemistry to polar ozone depletion have been discussed recently. The high-resolution He I photoelectron spectrum and the absolute (vacuum-UV) absorption cross section (6-25 eV) as well as the ionic fragmentation of chlorine dioxide (OCIO) are reported. The photoelectron spectrum is interpreted in terms of exchange splitting effects of the various singlet and triplet cation states as well as by comparison to chemically related molecules. The vacuum-UV absorption spectrum shows different Rydberg series converging to the cation states. These Rydberg series and their vibrational progressions are assigned by term value arguments, dipole selection rules, and comparison with the photoelectron spectrum. Photoionization mass spectrometry is used for measurements of the ionization and fragmentation threshold of OCIO. The major fragment is ClO[sup +] which occurs above 13.4 eV. Thermomechanical data such as heats of formation and bond dissociation energies are derived. No evidence for isomerization of OClO[sup +] is found, as observed for the electronically excited neutral molecule. 54 refs., 6 figs., 7 tabs.

  11. Inhibitor treatment program for chlorine dioxide corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Edmondson, J.G.; Holder, E.P.

    1991-11-12

    This patent describes a method of inhibiting corrosion by chlorine dioxide in oil field waterflood systems by adding a sufficient amount of a corrosion inhibiting composition. It comprises a phosphonate, a copolymer consisting of repeating units of acrylic acid/allyl hydroxy propyl sulfonate ether, and a permangante.

  12. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis.

    Science.gov (United States)

    Hering, Thea; Mühldorf, Bernd; Wolf, Robert; König, Burkhard

    2016-04-18

    Chlorine gas or electropositive chlorine reagents are used to prepare chlorinated aromatic compounds, which are found in pharmaceuticals, agrochemicals, and polymers, and serve as synthetic precursors for metal-catalyzed cross-couplings. Nature chlorinates with chloride anions, FAD-dependent halogenases, and O2 as the oxidant. A photocatalytic oxidative chlorination is described based on the organic dye riboflavin tetraacetate mimicking the enzymatic process. The chemical process allows within the suitable arene redox potential window a broader substrate scope compared to the specific activation in the enzymatic binding pocket.

  13. Kinetic models and pathways of ronidazole degradation by chlorination, UV irradiation and UV/chlorine processes.

    Science.gov (United States)

    Qin, Lang; Lin, Yi-Li; Xu, Bin; Hu, Chen-Yan; Tian, Fu-Xiang; Zhang, Tian-Yang; Zhu, Wen-Qian; Huang, He; Gao, Nai-Yun

    2014-11-15

    Degradation kinetics and pathways of ronidazole (RNZ) by chlorination (Cl2), UV irradiation and combined UV/chlorine processes were investigated in this paper. The degradation kinetics of RNZ chlorination followed a second-order behavior with the rate constants calculated as (2.13 ± 0.15) × 10(2) M(-2) s(-1), (0.82 ± 0.52) × 10(-2) M(-1) s(-1) and (2.06 ± 0.09) × 10(-1) M(-1) s(-1) for the acid-catalyzed reaction, as well as the reactions of RNZ with HOCl and OCl(-), respectively. Although UV irradiation degraded RNZ more effectively than chlorination did, very low quantum yield of RNZ at 254 nm was obtained as 1.02 × 10(-3) mol E(-1). RNZ could be efficiently degraded and mineralized in the UV/chlorine process due to the generation of hydroxyl radicals. The second-order rate constant between RNZ and hydroxyl radical was determined as (2.92 ± 0.05) × 10(9) M(-1) s(-1). The degradation intermediates of RNZ during the three processes were identified with Ultra Performance Liquid Chromatography - Electrospray Ionization - mass spectrometry and the degradation pathways were then proposed. Moreover, the variation of chloropicrin (TCNM) and chloroform (CF) formation after the three processes were further evaluated. Enhanced formation of CF and TCNM precursors during UV/chlorine process deserves extensive attention in drinking water treatment.

  14. Turbidity and chlorine demand reduction using alum and moringa flocculation before household chlorination in developing countries.

    Science.gov (United States)

    Preston, Kelsey; Lantagne, Daniele; Kotlarz, Nadine; Jellison, Kristen

    2010-03-01

    Over 1.1 billion people in the world lack access to improved drinking water. Diarrhoeal and other waterborne diseases cause an estimated 1.87 million deaths per year. The Safe Water System (SWS) is a household water treatment intervention that reduces diarrhoeal disease incidence among users in developing countries. Turbid waters pose a particular challenge to implementation of SWS programmes; although research shows that a 3.75 mg l(-1) sodium hypochlorite dose effectively treats turbid waters, users sometimes object to the strong chlorine taste and prefer to drink water that is more aesthetically pleasing. This study investigated the efficacy of two locally available chemical water treatments-alum and Moringa oleifera flocculation-to reduce turbidity and chlorine demand at turbidities of 10, 30, 70, 100 and 300 NTU. Both treatments effectively reduced turbidity (alum flocculation 23.0-91.4%; moringa flocculation 14.2-96.2%). Alum flocculation effectively reduced chlorine demand compared with controls at 30, 70, 100 and 300 NTU (p=0.01-0.06). Moringa flocculation increased chlorine demand to the point where adequate free chlorine residual was not maintained for 24 hours after treatment. Alum pretreatment is recommended in waters>or=30 NTU for optimum water disinfection. Moringa flocculation is not recommended before chlorination.

  15. Oxidative elimination of cyanotoxins: comparison of ozone, chlorine, chlorine dioxide and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Onstad, Gretchen D; Kull, Tomas P J; Metcalf, James S; Acero, Juan L; von Gunten, Urs

    2007-08-01

    As the World Health Organization (WHO) progresses with provisional Drinking Water Guidelines of 1 microg/L for microcystin-LR and a proposed Guideline of 1 microg/L for cylindrospermopsin, efficient treatment strategies are needed to prevent cyanotoxins such as these from reaching consumers. A kinetic database has been compiled for the oxidative treatment of three cyanotoxins: microcystin-LR (MC-LR), cylindrospermopsin (CYN), and anatoxin-a (ANTX) with ozone, chlorine, chlorine dioxide and permanganate. This kinetic database contains rate constants not previously reported and determined in the present work (e.g. for permanganate oxidation of ANTX and chlorine dioxide oxidation of CYN and ANTX), together with previously published rate constants for the remaining oxidation processes. Second-order rate constants measured in pure aqueous solutions of these toxins could be used in a kinetic model to predict the toxin oxidation efficiency of ozone, chlorine, chlorine dioxide and permanganate when applied to natural waters. Oxidants were applied to water from a eutrophic Swiss lake (Lake Greifensee) in static-dose testing and dynamic time-resolved experiments to confirm predictions from the kinetic database, and to investigate the effects of a natural matrix on toxin oxidation and by-product formation. Overall, permanganate can effectively oxidize ANTX and MC-LR, while chlorine will oxidize CYN and MC-LR and ozone is capable of oxidizing all three toxins with the highest rate. The formation of trihalomethanes (THMs) in the treated water may be a restriction to the application of sufficiently high-chlorine doses.

  16. Chlorine hazard evaluation for the zinc-chlorine electric vehicle battery. Final technical report. [50 kWh

    Energy Technology Data Exchange (ETDEWEB)

    Zalosh, R. G.; Bajpai, S. N.; Short, T. P.; Tsui, R. K.

    1980-04-01

    Hazards associated with conceivable accidental chlorine releases from zinc-chlorine electric vehicle batteries are evaluated. Since commercial batteries are not yet available, this hazard assessment is based on both theoretical chlorine dispersion models and small-scale and large-scale spill tests with chlorine hydrate (which is the form of chlorine storage in the charged battery). Six spill tests involving the chlorine hydrate equivalent of a 50-kWh battery indicate that the danger zone in which chlorine vapor concentrations intermittently exceed 100 ppM extends at least 23 m directly downwind of a spill onto a warm (30 to 38/sup 0/C) road surface. Other accidental chlorine release scenarios may also cause some distress, but are not expected to produce the type of life-threatening chlorine exposures that can result from large hydrate spills. Chlorine concentration data from the hydrate spill tests compare favorably with calculations based on a quasi-steady area source dispersion model and empirical estimates of the hydrate decomposition rate. The theoretical dispersion model was combined with assumed hydrate spill probabilities and current motor vehicle accident statistics in order to project expected chlorine-induced fatality rates. These calculations indicate that expected chlorine fataility rates are several times higher in a city such as Los Angeles with a warm and calm climate than in a colder and windier city such as Boston. Calculated chlorine-induced fatality rate projections for various climates are presented as a function of hydrate spill probability in order to illustrate the degree of vehicle/battery crashworthiness required to maintain chlorine-induced fatality rates below current vehicle fatality rates due to fires and asphyxiations. 37 figures, 19 tables.

  17. Comparative efficacy of chlorine and chlorine dioxide regimes for condenser slime control in seawater cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, P.S.; Veeramani, P.; Ershath, M.; Rajamohan, R.; Harinath, Y.V.; Mohan, T.V.K.; Venugopalan, V.P. [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamil nadu (India)

    2010-07-01

    Chlorination has long been used as an effective and economic biocide for biofouling control in seawater cooling systems. However, the efficacy of chlorine is reduced in the presence of organic content of seawater and the inability of chlorine to effectively penetrate biofilms. Chlorine dioxide is being projected as a possible alternative to chlorine. Experiments were carried out with the help of a seawater circulating facility, in which direct comparison of the efficacy of the two biocides was possible using test condenser tube assemblies. The test condenser tubes made of titanium, SS 316L and Cu-Ni 90/10 were dosed with chlorine and chlorine dioxide. Each dose was evaluated for 30 days. Continuous and intermittent additions of chlorine (0.38 - 0.45 mg L{sup -1} TRO) and chlorine dioxide (0.4 - 0.5 mg L{sup -1}) were used, along with control. The flow velocity in the tubes was maintained at 1.5 m/s. Results of the study showed that the efficacy of the biocide to control biofilms depended on the biocide and the material. Continuous chlorination resulted in 75% reduction of viable counts on titanium, followed by 24% reduction on CuNi and 6% reduction on SS 316L surfaces, as compared to the control. When compared to continuous chlorination, increase in bacterial density in the tubes was observed at different regimes of intermittent chlorination. On SS 316L and Cu-Ni surfaces, intermittent chlorination for 1h, once every 3 h, appeared to give adequate protection. Continuous addition of chlorine dioxide resulted in 99% reduction of viable counts on titanium surfaces, followed by 28% reduction on SS 316 L surfaces and 52% reduction on Cu-Ni surfaces, as compared to the controls. The data indicate that the efficacy of biocides to control biofilms depend on not only the biocide and its frequency of application but also the material of construction. (author)

  18. [Contamination characteristics of short-chain chlorinated paraffins in edible fish of Shanghai].

    Science.gov (United States)

    Jiang, Guo; Chen, Lai-guo; He, Qiu-sheng; Meng, Xiang-zhou; Feng, Yong-bin; Huang, Yu-mei; Tang, Cai-ming

    2013-09-01

    According to the local habit of eating fish, in a total of 68 samples, 8 kinds of different trophic levels of edible fish collected in Shanghai were determined in terms of concentration and distribution profile of short chain chlorinated paraffin (SCCPs) in muscles to investigate the pollution status of SCCPs in edible fish from the Yangtze River Delta region. The results indicated that the concentrations (dw) of SCCPs in edible fish were in the range of 36-801 ng x g(-1). With the increase in carbon chain length, the concentration of SCCPs decreased. In addition, lower chlorinated (Cl6-Cl8) and shorter chain (Cl10, C11) congeners were the dominant chlorine and carbon homologues groups, respectively, contributing a total relative abundance of 61.46%-82.50% to the total abundance of SCCPs. The levels of SCCPs in fish of Shanghai were in the medium level worldwide, and the distribution pattern was in line with those of the domestic and foreign studies.

  19. Synthesis and optical properties of chlorin monomer, dimer and trimer on an amino nitrogen atom.

    Science.gov (United States)

    Tamiaki, Hitoshi; Nagai, Tomoaki; Tanaka, Takuya; Tatebe, Tomohiro

    2015-09-01

    Naturally occurring chlorophyll-a was chemically modified to methyl 3-aminomethyl-pyropheophorbides-a including primary, secondary, and tertiary amines. Reductive amination of methyl pyropheophorbide-d possessing the 3-formyl group with ammonia efficiently gave a chlorin dimer covalently linked with CH2NHCH2 at the 3-position, which was transformed into a trimer through the substitution at the amino group. Conformational analyses by (1)H NMR spectroscopic observation and molecular modeling estimation indicated that the dimer and trimer were apt to form closely packed structures. Chlorin chromophores in the dimer and trimer were weakly interacted in dichloromethane to shift their Qy absorption bands to longer wavelengths by 4-6nm than the maxima of the corresponding monomer. In the red-shifted Qy region, the trimer gave an S-shaped circular dichroism band by exciton coupling of composite chlorin units. All the semi-synthetic chlorophyll derivatives were highly fluorescent and no intramolecular quenching was observed even in the trimer. The behaviors would be ascribable to the formation of compact conformers and suppression of intramolecular motion, which are important to construct light-harvesting antenna complexes in phototrophs and their model systems.

  20. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

    In this work, accurate calculations of standard enthalpies of formation of chlorine fluorides (ClF$_n$, n=1--7; Cl$_2$F and Cl$_3$F$_2$) were performed through the isodesmic reactions scheme. It is argued that, for many chlorine fluorides, the gold standard method of quantum chemistry (CCSD(T)) is not capable to predict enthalpy values nearing chemical accuracy if atomization scheme is used. This is underpinned by a thorough analysis of total atomization energy results and the inspection of multireference features of these compounds. Other thermodynamic quantities were also calculated at different temperatures. In order to complement the energetic description, elimination curves were studied through density functional theory as a computationally affordable alternative to highly correlated wave function-based methods.

  1. Behavioral toxicology, risk assessment, and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Evangelista de Duffard, A.M.; Duffard, R. [Laboratorio de Toxicologia Experimental, Santa Fe (Argentina)

    1996-04-01

    Behavioral end points are being used with greater frequency in neurotoxicology to detect and characterize the adverse effects of chemicals on the nervous system. Behavioral measures are particularly important for neurotoxicity risk assessment since many known neurotoxicants do not result in neuropathology. The chlorinated hydrocarbon class consists of a wide variety of chemicals including polychlorinated biphenyls, clioquinol, trichloroethylene, hexachlorophene, organochlorine insecticides (DDT, dicofol, chlordecone, dieldrin, and lindane), and phenoxyherbicides. Each of these chemicals has effects on motor, sensory, or cognitive function that are detectable using functional measures such as behavior. Furthermore, there is evidence that if exposure occurs during critical periods of development, many of the chlorinated hydrocarbons are developmental neurotoxicants. Developmental neurotoxicity is frequently expressed as alterations in motor function or cognitive abilities or charges in the ontogeny of sensorimotor reflexes. Neurotoxicity risk assessment should include assessments of the full range of possible neurotoxicological effects, including both structural and functional indicators of neurotoxicity. 121 refs., 1 tab.

  2. A comparison of iodinated trihalomethane formation from chlorine, chlorine dioxide and potassium permanganate oxidation processes.

    Science.gov (United States)

    Zhang, Tian-Yang; Xu, Bin; Hu, Chen-Yan; Lin, Yi-Li; Lin, Lin; Ye, Tao; Tian, Fu-Xiang

    2015-01-01

    This study compared the formation of iodinated trihalomethanes (I-THMs) from iodide-containing raw waters oxidized by chlorine, chlorine dioxide (ClO₂) and potassium permanganate (KMnO₄) at different oxidant concentrations, reaction times, pHs, initial iodide concentrations and bromide to iodide mass ratios. Among the six investigated I-THMs, iodoform was the major species formed during the oxidation using chlorine, ClO₂ and KMnO₄. When oxidant concentration increased from 0.1 to 3.0 mg/L, the formation of I-THMs increased and then decreased for chlorine and ClO₂, but kept increasing for KMnO₄. As the reaction time went by, I-THM concentration increased to a plateau within 10 h (ClO₂ within only 1 h, especially) for all the three oxidants. I-THM formation gradually increased from pH 3.0 to 9.0 and remained stable at pH values higher than 7.5 for chlorine; however, for ClO₂ and KMnO₄ the highest I-THM formation showed at pH 7.0 and 7.5, respectively. As initial iodide concentration increased from 20 to 800 μg/L, the total amount and species of I-THMs increased for the three oxidants. Iodide contributed to I-THM formation much more significantly than bromide.

  3. The gas phase chlorination of ethane

    Energy Technology Data Exchange (ETDEWEB)

    Olsbye, Unni; Myhrvold, Elisabeth M.; Slagtern, Aase; Dahl, Ivar M. [SINTEF Applied Chemistry, Oslo (Norway)

    1999-07-01

    Light alkanes are dehydrogenated to their corresponding olefins before further reactions to more valuable chemicals. The conversion of ethane to ethene in a steam cracker requires the addition of a substantial amount of heat (90 kJ/mol). Oxidative processes for ethane dehydrogenation could in principle be carried out adiabatically, however, the oxidation selectivity towards hydrogen is too low in existing systems, which leads to low ethene selectivities. This paper discusses the potential for light alkane derivatization through chlorination.

  4. Thermal diffusion of chlorine in uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y.; Toulhoat, N.; Moncoffre, N.; Jaffrezic, H.; Gavarini, S. [Inst. de Physique Nucleaire de Lyon (IPNL), Villeurbanne (France); Martin, P. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, Saint-Paul lez Durance (France); Raimbault, L. [Centre d' Informatique Geologique (CIG), Ecole des Mines, Fontainebleau (France); Scheidegger, A.M. [Lab. for Waste Management, Nuclear Energy and Safety Dept. (NES), Paul Scherrer Inst. Villigen PSI (Switzerland)

    2006-07-01

    In a nuclear reactor, isotopes such as {sup 35}Cl present as impurities in the nuclear fuel are activated by thermal neutron capture. During interim storage or geological disposal of nuclear fuel, the activation products such as {sup 36}Cl may be released from the fuel to the geo/biosphere and contribute to the ''instant release fraction'' as they are likely to migrate in defects and grain boundaries. In order to differentiate diffusion mechanisms due to ''athermal'' processes during irradiation from thermally activated diffusion, both irradiation and thermal effects must be assessed. This work concerns the measurement of the thermal diffusion coefficient of chlorine in UO{sub 2}. {sup 37}Cl was implanted at a 10{sup 13} at/cm{sup 2} fluence in depleted UO{sub 2} samples which were then annealed in the 900-1200 C temperature range and finally analyzed by secondary ion mass spectrometry (SIMS) to obtain {sup 37}Cl depth profiles. The migration process appears to be rather complex, involving mechanisms such as atomic, grain boundary, directed diffusion along preferential patterns as well as trapping into sinks before successive effusion. However, using a diffusion model based on general equation of transport, apparent diffusion coefficients could be calculated for 1000 and 1100 C and a mean activation energy of 4.3 eV is proposed. This value is one of the lowest values compared to those found in literature for other radionuclides pointing out a great ability of chlorine to migrate in UO{sub 2} at relatively low temperatures. In order to unequivocally determine the diffusion behaviour of both implanted and pristine chlorine before and after thermal annealing, the structural environment of chlorine in UO{sub 2} was examined using micro X-ray fluorescence (micro-XRF) and micro X-ray absorption spectroscopy (micro-XAS). (orig.)

  5. Hydraulic fracturing with chlorine dioxide cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.A.; Newlove, J.C.; Horton, R.L.

    1990-10-23

    This patent describes a method for fracturing a subterranean formation penetrated by a wellbore. It comprises: injecting a fracturing fluid into the formation to form a vertical fracture therein, the fracturing fluid being gelled with a polymer selected from guar, guar derivatives, acrylamide, acrylamide derivatives, cellulose, cellulose derivatives, and mixtures thereof and crosslinked with an organometallic crosslinking compound and having temperature stability above about 175{degrees} F.; packing the fracture with particulate propping agent; backflowing fluids from the formation through the propped fracture to remove a portion of the polymer; injecting at matrix rates sufficient aqueous solution of chlorine dioxide down the wellbore and into the propped fracture to penetrate at least 60 feet of the propped fracture length and contact polymer in the fracturing fluid and polymer residue in the propped fracture and on the fracture walls, the amount of the chlorine dioxide in the aqueous medium being sufficient to degrade polymer in the fracturing fluid and polymer residue; permitting the chlorine dioxide to remain in contact with the polymer in the fracturing fluid and with the polymer residue on the fracture walls and in the fracture for sufficient time to degrade the polymer thereby reducing the fracturing fluid viscosity and dissolving portions of the polymer residue; and flowing formation fluid from the formation through the propped fracture and into the wellbore to remove substantial portions of the polymer and degraded polymer from the fracture.

  6. Chlorine Monoxide in the Antarctic Spring Stratosphere.

    Science.gov (United States)

    Jaramillo-Ayerbe, Mauricio

    1988-06-01

    A series of observations of stratospheric chlorine monoxide (ClO) were carried out during the austral springs of 1986 and 1987 in McMurdo Station, Antarctica, as part of two experimental campaigns sent to investigate the seasonal decrease in ozone over the antarctic continent (the ozone "hole"). Measurements of the vertical distribution of ClO were obtained by high resolution ground-based emission spectroscopy at 278 GHz, using the Stony Brook mm-wave receiver. They show the presence of an anomalous layer of lower stratospheric ClO which is not observed at other latitudes. This anomalous layer is centered at ~20 km altitude and exhibits a pronounced diurnal variation, reaching a maximum at midday and disappearing at night. During the period of Sep. 20-24, 1987, the lower-stratospheric ClO had a maximum volume mixing ratio of 1.8_sp{+0cdot5}{ -0cdot9} ppbv. A normal ClO layer centered at ~36 km was also observed, with concentrations and diurnal behavior similar to those seen in tropical latitudes. These findings are evidence of anomalous chlorine chemistry taking place in the lower stratosphere during the antarctic spring, and indicate that increasing anthropogenic chlorine is a prime causative agent in the formation of the ozone hole.

  7. Electric plasma discharge combustion synthesis of chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dotson, R. L.; Geren, G. W.

    1984-09-18

    A process for the production of chlorine dioxide comprises feeding an inert gas to a reaction zone and applying an electrical discharge to the inert gas to produce a high temperature plasma. Chlorine gas and oxygen gas are supplied simultaneously to the reaction zone and reacted in the plasma to produce a gaseous mixture comprised of chlorine dioxide, chlorine, oxygen and inert gas, the molar ratio of oxygen to chlorine in the reaction zone being at least about 2.5;1. The gaseous mixture is recovered from the reaction zone. Chlorine dioxide, which may be recovered as a gas or reacted to produce an alkali metal chlorite, is employed as a bleaching agent and a water treatment agent.

  8. Method of improving formation permeability using chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, L.A.; Williams, D.A.

    1991-07-16

    This patent describes a method of treating a sandstone formation containing clays or silicates. It comprises injection a treating liquid into the formation comprising an aqueous solution of: from 50 to 4,200 ppm chlorine dioxide and from 1 to 85 volume percent of carbon dioxide; permitting the chlorine dioxide to react with material in the formation; and thereafter injecting into the formation an acid solution capable of dissolving the reaction products of chlorine dioxide and the clays and silicates.

  9. Treatment of algae-induced tastes and odors by chlorine, chlorine dioxide and permanganate

    OpenAIRE

    Buffin, Lisa Webster

    1992-01-01

    Chlorine (C12(sq»' chlorine dioxide (Cl02 ) and potassium permanganate (KMn04) were evaluated as oxidants for the removal of grassy and cucumber odors associated with the pure compounds, cis-3-hexenol and trans-2, cis-6-nonadienal, respectively, and for the removal of fishy odors associated with a culture of an alga, Synura petersenii. The effects of the oxidants on the pure compounds were assessed both by Flavor Profile Analysis (FPA) and gas chromatography/mass spectrometry (GC/MS). The ef...

  10. Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles%Cyclopalladated Ferrocenylimine Catalyzed Chlorination of 2-Arylbenzoxazoles

    Institute of Scientific and Technical Information of China (English)

    冷瑜婷; 杨帆; 吴养洁; 李克

    2011-01-01

    An efficient and facile protocol for palladacycle-catalyzed chlorination of 2-arylbenzoxazoles was developed. The results represent the first examples involving the palladacycle as the catalyst for such chlorination. This chlori- nation was not a ligand-directed ortho-C--H activation, but an electrophilic substitution process at the para-position of the nitrogen atom in the benzo ring of benzoxazole moiety, the regiochemistry of which had been confirmed by HMBC spectral analysis. The catalytic system could tolerate various halogen atoms, such as F, Cl and Br, affording the corresponding products in moderate to excellent yields.

  11. Chlorinated and nitrogenous disinfection by-product formation from ozonation and post-chlorination of natural organic matter surrogates.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Rifai, Omar; Ali, Hussain; Graham, Nigel J D

    2014-09-01

    Ozonation before chlorination is associated with enhanced formation of chloropicrin, a halonitromethane disinfection by-product (DBP), during drinking water treatment. In order to elucidate reasons for this, five natural organic matter (NOM) surrogates were treated using both chlorination and ozonation-chlorination under controlled laboratory conditions. Selected surrogates comprised two phenolic compounds, two free amino acids and one dipeptide; these were resorcinol, 3-aminophenol, L-aspartic acid, β-alanine and ala-ala, respectively. Quantified DBPs included chloropicrin, chloroform, dichloroacetonitrile and trichloroacetonitrile. Relative to chlorination alone, increases in the formation of chloropicrin from ozonation-chlorination varied from 138% for 3-aminophenol to 3740% for ala-ala for the four amine surrogates. This indicates that ozone is more effective than chlorine in mediating a rate-limiting oxidation step in chloropicrin formation, most plausibly involving conversion of an amine group to a nitro group. While both hydrophilic and hydrophobic surrogates acted as chloropicrin precursors, ala-ala was the most reactive precursor following ozonation-chlorination. Since peptides are far commoner in drinking water sources than free amino acids, further research into chemical oxidation of these species by ozone and chlorine is recommended. In contrast, oxidation with ozone prior to chlorination reduced chloroform formation moderately for the two phenolic compounds.

  12. 46 CFR 46.10-60 - Control.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Control. 46.10-60 Section 46.10-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Administration § 46.10-60 Control. (a) The District Director of Customs or the Coast Guard District Commander...

  13. 46 CFR 46.10-65 - Construction.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Construction. 46.10-65 Section 46.10-65 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Administration § 46.10-65 Construction. (a) The watertight subdivision of every passenger...

  14. Chloroxyanion Residue Quantification in Cantaloupes Treated with Chlorine Dioxide Gas.

    Science.gov (United States)

    Kaur, Simran; Smith, David J; Morgan, Mark T

    2015-09-01

    Previous studies show that treatment of cantaloupes with chlorine dioxide (ClO2) gas at 5 mg/liter for 10 min results in a significant reduction (P < 0.05) in initial microflora, an increase in shelf life without any alteration in color, and a 4.6- and 4.3-log reduction of Escherichia coli O157:H7 and Listeria monocytogenes, respectively. However, this treatment could result in the presence of chloroxyanion residues, such as chloride (Cl(-)), chlorite (ClO2(-)), chlorate (ClO3(-)), and perchlorate (ClO4(-)), which, apart from chloride, are a toxicity concern. Radiolabeled chlorine dioxide ((36)ClO2) gas was used to describe the identity and distribution of chloroxyanion residues in or on cantaloupe subsequent to fumigation with ClO2 gas at a mean concentration of 5.1 ± 0.7 mg/liter for 10 min. Each treated cantaloupe was separated into rind, flesh, and mixed (rind and flesh) sections, which were blended and centrifuged to give the corresponding sera fractions. Radioactivity detected, ratio of radioactivity to mass of chlorite in initial ClO2 gas generation reaction, and distribution of chloroxyanions in serum samples were used to calculate residue concentrations in flesh, rind, and mixed samples. Anions detected on the cantaloupe were Cl(-) (∼ 90%) and ClO3(-) (∼ 10%), located primarily in the rind (19.3 ± 8.0 μg of Cl(-)/g of rind and 4.8 ± 2.3 μg of ClO3(-)/g of rind, n = 6). Cantaloupe flesh (∼ 200 g) directly exposed to(36)ClO2 gas treatment showed the presence of only Cl(-) residues (8.1 ± 1.0 μg of Cl(-)/g of flesh, n = 3). Results indicate chloroxyanion residues Cl(-) and ClO3(-) are only present on the rind of whole cantaloupes treated with ClO2 gas. However during cutting, residues may be transferred to the fruit flesh. Because Cl(-) is not toxic, only ClO3(-) would be a toxicity concern, but the levels transferred from rind to flesh are very low. In the case of fruit flesh directly exposed to ClO2 gas, only nontoxic Cl(-) was detected. This

  15. Effects of chlorine and chlorine dioxide on mutagenic activity of Lake Kinnereth water

    Energy Technology Data Exchange (ETDEWEB)

    Guttman-Bass, N.; Bairey-Albuquerque, M.; Ulitzur, S.; Chartrand, A.; Rav-Acha, C.

    1987-03-01

    Water from Lake Kinnereth (Israel) was tested for the presence of mutagenic activity, with and without disinfection by chlorine and chlorine dioxide. The samples were assayed for activity with two Ames Salmonella typhimurium tester strains, TA 104 and TA 100, and by a luminescent genotoxic assay with a dark mutant strain of Photobacterium fischeri. The water concentrates were mutagenic in strain TA 104 and in the luminescent assay, reaching positive mutagenic activities in the equivalent of 20 mL of water. Chlorination did not greatly affect the net mutagenic activity, although ClO/sub 2/ apparently reduced it. Humic acids were isolated from lake sediment and were assayed with and without disinfection in distilled water and in lake water from which the organic components were removed. The humic acids were mutagenic in both test systems, and treatment with Cl/sub 2/ generally decreased the net activity. ClO/sub 2/ also tended to decrease the mutagenic activity, and cytotoxic effects were observed in some of the samples. Conversely, commercial humic acid was mutagenic only after chlorination on strain TA 100. 54 references, 3 figures, 6 tables.

  16. Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments ▿

    Science.gov (United States)

    Mogoa, Emerancienne; Bodet, Charles; Morel, Franck; Rodier, Marie-Hélène; Legube, Bernard; Héchard, Yann

    2011-01-01

    Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii. PMID:21602398

  17. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, Karen; Michael J. Truex; Charles J. Newell; Brian Looney

    2007-02-28

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  18. Advantages and disadvantages of chemical oxidation and disinfection by ozone and chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F.; Richard, Y.; Montiel, A.; Musquere, P.

    1981-04-01

    Ozone and chlorine dioxide present definite advantages and disadvantages over chlorination. Chlorination, particularly for the removal of ammonia and the maintenance of a disinfectant residual in the distribution system has decisive advantages and will be difficult to replace. Ozone and chlorine dioxide seem to produce fewer carcinogenic by-products but the risk for acute toxicity, especially from the chlorites which follow chlorine dioxide, is higher than with chlorine. Chlorine dioxide and more particularly ozone should be considered as useful complements to chlorination, but no strong oxidative treatment should be applied before most of the organic matter has been removed.

  19. 78 FR 66767 - Chlorinated Isocyanurates From China and Japan

    Science.gov (United States)

    2013-11-06

    ... publishing the notice in the Federal Register of September 10, 2013 (78 FR 55293). The conference was held in... COMMISSION Chlorinated Isocyanurates From China and Japan Determinations On the basis of the record \\1... injured by reason of imports from China and Japan of chlorinated isocyanurates, provided for...

  20. Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

    Science.gov (United States)

    Sander, Stanley P.; Friedl, Randall R.

    1993-01-01

    Over the last five years substantial progress has been made in defining the realm of new chlorine chemistry in the polar stratosphere. Application of existing experimental techniques to potentially important chlorine-containing compounds has yielded quantitative kinetic and spectroscopic data as well as qualitative mechanistic insights into the relevant reactions.

  1. Chlorine Dioxide Induced Multiple Chemical Sensitivity: MMPI Validity Problems.

    Science.gov (United States)

    Tentoni, Stuart C.

    This paper discusses Minnesota Multiphasic Personality Inventory (MMPI) data obtained from individuals exposed to chlorine dioxide in the workplace who developed Multiple Chemical Sensitivity Syndrome. The paper explores current research on chlorine dioxide exposed persons who were misdiagnosed on the basis of MMPI interpretations. Difficulties…

  2. 75 FR 23303 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-05-03

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice that it has instituted reviews... revocation of the antidumping duty orders on chlorinated isocyanurates from China and Spain would be...

  3. 75 FR 51113 - Chlorinated Isocyanurates From China and Spain

    Science.gov (United States)

    2010-08-18

    ... COMMISSION Chlorinated Isocyanurates From China and Spain AGENCY: United States International Trade... chlorinated isocyanurates from China and Spain. SUMMARY: The Commission hereby gives notice of the scheduling... from China and Spain would be likely to lead to continuation or recurrence of material injury within...

  4. Chlorine-containing natural compounds in higher plants

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1986-01-01

    More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

  5. Environmental behaviour of short-chain chlorinated paraffins in aquatic and terrestrial ecosystems of Ny-Ålesund and London Island, Svalbard, in the Arctic.

    Science.gov (United States)

    Li, Huijuan; Fu, Jianjie; Pan, Wenxiao; Wang, Pu; Li, Yingming; Zhang, Qinghua; Wang, Yawei; Zhang, Aiqian; Liang, Yong; Jiang, Guibin

    2017-07-15

    The environmental behaviour of short-chain chlorinated paraffins (SCCPs) was investigated in both aquatic and terrestrial ecosystems in the Arctic. The mean concentrations of SCCPs in the aquatic and terrestrial samples were 178.9ng/g dry weight (dw) and 157.2ng/g dw, respectively. Short carbon chain (C10) and less-chlorinated (Cl6) congener groups were predominant in the Arctic samples, accounting for 48.6% and 34.8% of the total SCCPs, respectively. The enrichment of lighter SCCP congener groups (i.e., fewer chlorine atoms with shorter carbon chain lengths) indicated that the fractionation process occurred during long-range transport. The biomagnification factor (BMF) was 0.46 from gammarid to cod, which indicated that the SCCPs did not biomagnify between these two species. The soil-vegetation bioaccumulation factor (BAF) of SCCPs was 29.9, and C13 and Cl7, 8 congener groups tended to accumulate in the terrestrial vegetation. Regression analysis (BAFs=10.9×#C+5.6×#Cl-125.2, R=0.53, P<0.01) showed that the number of carbon and chlorine atoms influenced the bioaccumulative behaviour of SCCPs and suggested that the number of carbon atoms had a greater influence on the BAFs of SCCPs in the terrestrial ecosystem than did the number of chlorine atoms.

  6. Effects of short-chain chlorinated paraffins on soil organisms.

    Science.gov (United States)

    Bezchlebová, Jitka; Cernohlávková, Jitka; Kobeticová, Klára; Lána, Jan; Sochová, Ivana; Hofman, Jakub

    2007-06-01

    Despite the fact that chlorinated paraffins have been produced in relatively large amounts, and high concentrations have been found in sewage sludge applied to soils, there is little information on their concentrations in soils and the effect on soil organisms. The aim of this study was to investigate the toxicity of chlorinated paraffins in soils. The effects of short-chain chlorinated paraffins (64% chlorine content) on invertebrates (Eisenia fetida, Folsomia candida, Enchytraeus albidus, Enchytraeus crypticus, Caenorhabditis elegans) and substrate-induced respiration of indigenous microorganisms were studied. Differences were found in the sensitivity of the tested organisms to short-chain chlorinated paraffins. F. candida was identified as the most sensitive organism with LC(50) and EC(50) values of 5733 and 1230 mg/kg, respectively. Toxicity results were compared with available studies and the predicted no effect concentration (PNEC) of 5.28 mg/kg was estimated for the soil environment, based on our data.

  7. Low-Cost Graphite-Based Free Chlorine Sensor.

    Science.gov (United States)

    Pan, Si; Deen, M Jamal; Ghosh, Raja

    2015-11-01

    Pencil lead was used to fabricate a graphite-based electrode for sensing applications. Its surface was electrochemically modified using ammonium carbamate to make it suitable for sensing free chlorine in water samples. Chlorine is widely used as a disinfectant in the water industry, and the residual free chlorine concentration in water distributed to the consumers must be lower than that stipulated by regulatory bodies. The graphite-based amperometric sensor gave a selective and linear response to free chlorine in the relevant concentration range and no response to commonly interfering ions. It was evaluated further for storage stability, response time, and hysteresis. This sensor is being proposed as a low-cost device for determining free chlorine in water samples. Its ease-of-use, limitations, and feasibility for mass-production and application is discussed.

  8. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

    CHAO WANG; GUAN-GHUA LU; YAN-JIE ZHOU

    2007-01-01

    Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes,Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

  9. Synergetic Inactivation of Microorganisms in Drinking Water by Short-term Free Chlorination and Subsequent Monochloramination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To introduce synergetic inactivation of microorganisms in drinking water by short-term free chlorination for less than 15 minutes followed by monochloramination. Methods Indicator microorganisms such as Escherichia coli,Staphylococcus aureus, Candida albicans, and spores of Bacillus subtilis were used to assess the efficiency of sequential chlorination and free chlorination. Results The sequential chlorination was more efficient in inactivating these microorganisms than free chlorination, indicating that synergy was provided by free chlorine and monochloramine. Ammonia addition time, temperature and pH had influences on this synergy. Conclusion The possible mechanism of this synergy might involve three aspects: free chlorine causing sublethal injury to microorganisms and monochloramine further inactivating them; different ability of free chlorine and monochloramine to penetrate and inactivate microorganism congeries; and higher concentration of residual chlorine in sequential chlorination than in free chlorination.

  10. Chlorine inactivation of Tubifex tubifex in drinking water and the synergistic effect of sequential inactivation with UV irradiation and chlorine.

    Science.gov (United States)

    Nie, Xiao-Bao; Li, Zhi-Hong; Long, Yuan-Nan; He, Pan-Pan; Xu, Chao

    2017-06-01

    The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × timereaction) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, Ea, induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (CODMn) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and CODMn concentrations contributed to the inactivation of T. tubifex.

  11. Change in genotoxicity of wastewater during chlorine dioxide and chlorine disinfections and the influence of ammonia nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Lisha; HU Hongying; WANG Chao; Koichi Fujie

    2007-01-01

    The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test.The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater first decreased rapidly and then tended to be stable,while when the chlorine dosage was increased from 0 to 30 mg/L,the genotoxicity of wastewater changed diversely for different samples.It was then found that ammonia nitrogen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater,while it greatly affected the change of genotoxicity during chlorine disinfection of wastewater.When the concentration of ammonia nitrogen was low(<10-20mg/L),the genotoxicity of wastewater decreased after chlorine disinfection,and when the concentration of ammonia nitrogen was high(>10-20 mg/L),the genotoxicity of wastewater increased after chlorine disinfection.

  12. Impact of vegetation and ecosystems on chlorine(-36) cycling and its modeling: from simplified approaches towards more complex biogeochemical tools

    Science.gov (United States)

    Thiry, Yves; Redon, Paul-Olivier; Gustafsson, Malin; Marang, Laura; Bastviken, David

    2013-04-01

    al., 2012), average Cl residence time in forest soils calculated for Clin and Clorg together was 5-fold higher that the residence time estimated for Clin alone (Redon et al., 2011), locally, Cl amount taken up by certain vegetation types can be larger than annual atmospheric deposits, the Cl in excess being recycled mainly by throughfall (Thiry, 2010), root uptake and chlorine transformation rates in soils are essential to calibrate dynamic compartment models since those processes control the persistence of chlorine in the whole system but data are still deficient for different land uses (Van den Hoof & Thiry, 2012). References: Bastviken, D., Thomsen, F., Svensson, T., Karlsson, S., Sandén, P., Shaw, G., Matucha, M., and Öberg, G. (2007). Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter. Geochim. Cosmochim. Acta, 71: 3182-3192. Gustavsson, M., Karlsson, S.,Öberg, G.,Sandén, P.,Svensson, T.,Valinia, S.,Thiry, Y. and Bastviken, D. (2012). Organic matter chlorination rates in different boreal soils: the role of soil organic matter content. Environmental Science & Technology, 46 (3): 1504-1510 Thiry, Y., 2010. Contribution à l'étude du cycle biogéochimique du chlore en écosystème forestier: cas d'un peuplement de pin sylvestre. Rapport Andra n° ENV.NT.ASTR.10.0068. IAEA (2010). Handbook of parameter values for the prediction of radionuclide transfer to humans in terrestrial and freshwater environments. Technical Report Series n° 472, Vienna, Austria. Öberg, G. (1998). Chloride and organic chlorine in soil. Acta hydrochimica et hydrobiologica, 26 (3): 137-144. Redon, P-O., Abdelouas, A., Bastviken, D., Cecchini, S. Nicolas, M. and Thiry, Y. (2011). Chloride and organic chlorine in forest soils: storage, residence times, and influence of ecological conditions. Environmental Science & Technology, 45: 7202-7208. Redon, P-O., Jolivet, C., Saby, N., Abdelouas, A.and Thiry, Y. (2012). Occurrence of natural organic

  13. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

    Time-resolved mass spectrometry and time-resolved photoelectron spectroscopy are used to study the ultrafast photodissociation dynamics of chlorine dioxide, an important constituent in stratospheric ozone depletion. Chapter 1 introduces these pump/probe techniques, in which a femtosecond pump pulse excites a molecule to a dissociative state. At a later time, a second femtosecond probe pulse ionizes the molecule. The resulting mass and photoelectron spectra are acquired as a function of the delay between the pump and probe pulses, which follows the evolution of the molecule on the excited state. A comparison to other techniques used to study reaction dynamics is discussed. Chapter 2 includes a detailed description of the design and construction of the experimental apparatus, which consists of a femtosecond laser system, a molecular beam time-of-flight spectrometer, and a data acquisition system. The time-of-flight spectrometer is specifically designed to have a short flight distance to maximize the photoelectron collection efficiency without degrading the resolution, which is limited by the bandwidth of the femtosecond laser system. Typical performance of the apparatus is demonstrated in a study of the time-resolved photoelectron spectroscopy of nitric oxide. The results of the time-resolved mass spectrometry experiments of chlorine dioxide are presented in Chapter 3. Upon excitation to the A {sup 2}A{sub 2} state near 3.2 eV, the molecule dissociates through an indirect two-step mechanism. The direct dissociation channel has been predicted to be open, but is not observed. A quantum beat is observed in the OClO{sup +} species, which is described as a vibrational coherence of the optically prepared A {sup 2}A{sub 2} state. Chapter 4 presents the results of the time-resolved photoelectron experiments of chlorine dioxide. At short delay time, the quantum beat of the OClO{sup +} species is observed in the X {sup 1}A{sub 1} state of the ion. At infinite delay, the signal

  14. Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

    Science.gov (United States)

    Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

    2016-12-20

    Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br(-) and Cl(-) may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

  15. Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

    KAUST Repository

    Khan, Muhammad Tariq

    2015-04-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full–scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  16. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pipon, Y. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France) and Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France)]. E-mail: pipon@ipnl.in2p3.fr; Bererd, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Universite Claude Bernard Lyon-1, Institut Universitaire de Technologie (IUT A), 94, boulevard Niels Bohr, 69622 Villeurbanne cedex (France); Moncoffre, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Peaucelle, C. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Toulhoat, N. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Commissariat a l' Energie Atomique (CEA), DEN/Saclay, 91191 Gif sur Yvette cedex (France); Jaffrezic, H. [Universite Claude Bernard Lyon-1/Institut de Physique Nucleaire de Lyon (IPNL), 4, rue Enrico Fermi, 69622 Villeurbanne cedex (France); Raimbault, L. [Ecole des Mines de Paris, Centre de Geosciences, 35 rue Saint Honore, F-77305 Fontainebleau cedex (France); Sainsot, P. [Institut National des Sciences Appliquees de Lyon (INSA), UMR 5514, F-69621 Villeurbanne cedex (France); Carlot, G. [Commissariat a l' Energie Atomique (CEA), Centre de Cadarache, DEN/DEC/SESC/LLCC, 13108 Saint-Paul lez Durance (France)

    2007-04-15

    The radiation enhanced diffusion of chlorine in UO{sub 2} during heavy ion irradiation is studied. In order to simulate the behaviour of {sup 36}Cl, present as an impurity in UO{sub 2}, {sup 37}Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV {sup 127}I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 x 10{sup -14} cm{sup 2} s{sup -1}, reflect the high mobility of chlorine in UO{sub 2} during irradiation with fission products.

  17. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    Science.gov (United States)

    Pipon, Y.; Bérerd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrézic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

    2007-04-01

    The radiation enhanced diffusion of chlorine in UO2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36Cl, present as an impurity in UO2, 37Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 × 10-14 cm2 s-1, reflect the high mobility of chlorine in UO2 during irradiation with fission products.

  18. Does chlorination of seawater reverse osmosis membranes control biofouling?

    Science.gov (United States)

    Khan, Muhammad Tariq; Hong, Pei-Ying; Nada, Nabil; Croue, Jean Philippe

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations.

  19. Removal effect on Mesocyclops leukarti and mutagenicity with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    ZUO Jin-long; CUI Fu-yi; QU Bo; ZHU Gui-bing

    2006-01-01

    Mesocyclops leukarti of zooplankton propagates excessively in eutrophic water body and it cannot be effectively inactivated by the conventional drinking water treatment process. In order to tackle this problem, a study of removal effect on Mesocyclops leukarti with chlorine dioxide in a waterworks was performed. The results showed that Mesocyclops leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation combined with the conventional drinking water treatment process.Higher oxidizability and molecular state of chlorine dioxide in water is the key to the inactivation of Mesocyclops leukarti. The chlorite, disinfection by-products (DBPs) of chlorine dioxide, was stable at 0.45 mg/L, which is lower than that critical value of the USEPA. GC-MS examination showed that the quantity of organic substance in the water treated by chlorine dioxide obviously decreased. Ames test further revealed that the mutagenicity was reduced by chlorine dioxide with respect to prechlorine. The propagation ofMesocyclops leukarti can be inactivated effectively and safely by chlorine dioxide pre-oxidation.

  20. Roles of reactive chlorine species in trimethoprim degradation in the UV/chlorine process: Kinetics and transformation pathways.

    Science.gov (United States)

    Wu, Zihao; Fang, Jingyun; Xiang, Yingying; Shang, Chii; Li, Xuchun; Meng, Fangang; Yang, Xin

    2016-11-01

    The UV/chlorine process, which forms several reactive species including hydroxyl radicals (HO) and reactive chlorine species (RCS) to degrade contaminants, is being considered to be an advanced oxidation process. This study investigated the kinetics and mechanism of the degradation of trimethoprim (TMP) by the UV/chlorine process. The degradation of TMP was much faster by UV/chlorine compared to UV/H2O2. The degradation followed pseudo first-order kinetics, and the rate constant (k') increased linearly as the chlorine dosage increased from 20 μM to 200 μM and decreased as pH rose from 6.1 to 8.8. k' was not affected by chloride and bicarbonate but decreased by 50% in the presence of 1-mg/L NOM. The contribution of RCS, including Cl, Cl2(-) and ClO, to the degradation removal rate was much higher than that of HO and increased from 67% to 87% with increasing pH from 6.1 to 8.8 under the experimental condition. The increasing contribution of RCS to the degradation with increasing pH was attributable to the increase in the ClO concentration. Kinetic modeling and radical scavenging tests verified that ClO mainly attacked the trimethoxybenzyl moiety of TMP. RCS reacted with TMP much faster than HOCl/OCl(-) to form chlorinated products (i.e., m/z 325) and chlorinated disinfection byproducts such as chloroform, chloral hydrate, dichloroacetonitrile and trichloronitromethane. The hydroxylation and demethylation of m/z 325 driven by HO generated m/z 327 and m/z 341. Meanwhile, reactions of m/z 325 with HO and RCS/HOCl/OCl(-) generated dichlorinated and hydroxylated products (i.e., m/z 377). All the chlorinated products could be further depleted to produce products with less degree of halogenation in the UV/chlorine process, compared to dark chlorination. The acute toxicity to Vibrio fischeri by UV/chlorine was lower than chlorination at the same removal rate of TMP. This study demonstrated the importance of RCS, in particular, ClO, in the degradation of micropollutants

  1. Simulating stable carbon and chlorine isotope ratios in dissolved chlorinated groundwater pollutants with BIOCHLOR-ISO

    Science.gov (United States)

    Höhener, Patrick

    2016-12-01

    BIOCHLOR is a well-known simple tool for evaluating the transport of dissolved chlorinated solvents in groundwater, ideal for rapid screening and teaching. This work extends the BIOCHLOR model for the calculation of stable isotope ratios of carbon and chlorine isotopes in chloroethenes. An exact solution for the three-dimensional reactive transport of a chain of degrading compounds including sorption is provided in a spreadsheet and applied for modeling the transport of individual isotopes 12C, 13C, 35Cl, 37Cl from a constant source. The model can consider secondary isotope effects that can occur in the breaking of Csbnd Cl bonds. The model is correctly reproducing results for δ13C and δ37Cl modeled by a previously published 1-D numerical model without secondary isotope effects, and is also reproducing results from a microcosm experiment with secondary chlorine isotope effects. Two applications of the model using field data from literature are further given and discussed. The new BIOCHLOR-ISO model is distributed as a spreadsheet (MS EXCEL) along with this publication.

  2. Characterization of Chlorinated Ethene Degradation in a Vertical Flow Constructed Wetland

    Science.gov (United States)

    2007-03-01

    pathway for chlorinated volatiles in phytoremediation applications. Although transpiration of chlorinated solvents has been confirmed in studies ... case study publications and conference presentations providing support for the use of constructed wetlands for the treatment of chlorinated solvent...groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE

  3. Safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water

    Energy Technology Data Exchange (ETDEWEB)

    Taymaz, K.; Williams, D.T.; Benoit, F.M.

    1979-01-01

    The safety of water treatment by chlorine dioxide oxidation of aromatic hydrocarbons commonly found in water and industrial wastewaters in the US was studied by observing the reactions of naphthalene and methylnaphthalenes in essentially chlorine-free, aqueous chlorine dioxide solutions. Naphthalene and methylnaphthalenes yielded chlorinated derivatives and oxidation products. Further research is recommended.

  4. Behavior and stability of adenosine triphosphate (ATP) during chlorine disinfection.

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems.

  5. Aqueous reactions of chlorine dioxide with hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Rav-Acha, C.; Choshen, E.

    1987-11-01

    In contrast to mechanisms proposed earlier in the literature, according to which chlorine dioxide (ClO/sub 2/) reacts with various hydrocarbons in aqueous media by abstracting allylic or benzylic hydrogens, it is shown that ClO/sub 2/ reacts with olefins through initial electron transfer. Hydrocarbons that can undergo facile oxidation, such as polycyclic aromatic hydrocarbons (PAH) and some olefins, react with ClO/sub 2/ quite rapidly, while saturated aliphatic hydrocarbons, some aromatic hydrocarbons, and olefins substituted with electron-withdrawing groups remain unreactive. This was substantiated by comparing the reactivities toward ClO/sub 2/ of a variety of hydrocarbons, including aliphatic and aromatic hydrocarbons, saturated and unsaturated acids, PAH, or cyclic and acyclic olefins. The results were supported by a detailed kinetic and product study of the reaction between ClO/sub 2/ and some model compounds.

  6. Effects of continuous chlorination on entrained estuarine plankton

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, S.J.; Foulk, H.R.

    1980-01-01

    Technical report: The effects of continuous chlorination in running sea water on entrained plankton were examined. The concentration of ATP was used as an indicator of biomass because: it is present in all living cells; the concentration is proportional to the living biomass; and dead cells lose ATP rapidly. Effects were measured by bioluminescence; luciferin-luciferase reagents from firefly lanterns were used to analyze ATP concentration. Results indicate that ATP measurement is an accurate, effective means of evaluating damage done to planktonic organisms by continuous chlorination. Further studies of the effects of low-concentration, continuous chlorination are recommended. (13 references, 1 table)

  7. Chlorine-36 and chlorine concentrations within several compartments of a deciduous forest ecosystem in Meuse/Haute-Marne (France)

    Science.gov (United States)

    Pupier, Julie; Benedetti, Lucilla; Bourles, Didier; Leclerc, Elisabeth; Thiry, Yves

    2013-04-01

    Chlorine-36 is a cosmogenic nuclide mainly produced in the atmosphere by interactions between energetic particles originating from the cosmic radiations and 40Ar. Because of its long half-life (T1-2 = 3.01 105 yr) and its high mobility, chlorine-36 is a critical radionuclide concerning radioactive waste repository sites. Moreover, it has been shown that inorganic chlorine could be enriched along the trophic chain due to its high solubility and bioavailability (Ashworth and Shaw, 2006). Additionally, many studies during the last decades have established that due to chlorination process, organic chlorine may account for a large proportion of the total soil chlorine pool (more than 80 % in surface soils of temperate ecosystems. Redon et al., 2012). The aim of this study is thus to measure chlorine-36 in all the compartments of the biogeochemical cycle, to better understand its recycling in the biosphere. The study site is the experimental beech forest site of the Andra long-term monitoring and testing system (OPE*). It is located at Montiers-sur-Saulx, North-East of France and is associated to the future radioactive waste repository site of Bure. Since March 2012, rainwater above (rainfall collected from a 45 m high tower built on purpose) and below (throughfall and stemflow) the canopy, has been collected monthly, as well as soil solutions (gravitational and bound waters) at four depths (0, 10, 30, 60 cm deep). Chlorine-36 and chlorine have been measured in the rainfall samples between March and July 2012 and in water solutions collected from all compartments of the biosphere using isotope dilution mass spectrometry at the french AMS national facility ASTER located at CEREGE. The results yielded from the rainfall samples allow to study the temporal fluctuations of chlorine-36 in the atmosphere, which represents the main inflow of chlorine-36 in its biogeochemical cycle. The first results indicate a flow increase during the late spring-early summer. Santos et al

  8. Selective determination of chlorine dioxide using gas diffusion flow injection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hollowell, D.A.; Pacey, G.E.; Gordon, G.

    1985-12-01

    An automated absorbance technique for the determination of aqueous chlorine dioxide has been developed by utilizing gas diffusion flow injection analysis. A gas diffusion membrane is used to separate the donor (sampling) stream from the acceptor (detecting) stream. The absorbance of chlorine dioxide is monitored at 359 nm. The first method uses distilled water as the acceptor stream and gives a detection limit of 0.25 mg/L chlorine dioxide. This system is over 550 times more selective for chlorine dioxide than chlorine. To further minimize chlorine interference, oxalic acid is used in the acceptor stream. The detection limit for this system is 0.45 mg/L chlorine dioxide. This second system is over 5400 times more selective for chlorine dioxide than chlorine. Both methods show excellent selectivity for chlorine dioxide over iron and manganese compounds, as well as other oxychlorinated compounds such as chlorite and perchlorate ions. 18 references, 7 figures, 3 tables.

  9. RESEARCH ON MATHEMATICAL SIMULATION OF RESIDUAL CHLORINE DECAY AND OPTIMIZATION OF CHLORINATION ALLOCATION OF URBAN WATER DISTRIBUTION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    TIAN Yi-mei; CHI Hai-yan; LI Hong; SHAN Jin-lin; ZHAI Chun-nian

    2005-01-01

    The concentration of Residual Chlorine (RC) frequently violates the standard in situations of urban water distribution system with large water supply area and long time of distribution.If chlorine dosage increases within water treatment plant, although RC in distribution system could meet water quality standard, Disinfection By-Products (DBPs) such as hydrocarbon halide rises.In the paper, a mathematical model of chlorine allocation optimization was presented based on reaction kinetics mechanism and optimization theory to solve the problem.The model includes the objective function of minimizing annual operation cost and constraints of RC standard and rational chlorination station distribution, and solving by 0-1 Integer Programming (IP).The model had been applied to a real water distribution system.The simulation results of the model showed that adding chlorine in water distribution system remarkably improved water quality and reduced the operation cost by 49.3% per year less than chlorine dosed only in water treatment plant to meet RC standard.The results prove adding chlorine in water distribution system based on the model can bring both technological and economic advancement.

  10. Emission inventory and provincial distribution of short-chain chlorinated paraffins in China.

    Science.gov (United States)

    Zhang, Boya; Zhao, Bu; Xu, Chun; Zhang, Jianbo

    2017-03-01

    Chlorinated paraffins (CPs) are used as flame retardants, plasticizers, and metalworking fluids, which have varying contents of toxic short-chain chlorinated paraffins (SCCPs). Based on the study of several relevant production and consumption sectors, this paper classifies the consumption of CPs among sectors and provides an emission inventory and the provincial emission distribution of SCCPs in China in 2010-2014 based on the consumption patterns and emission factors of each sector. The total emissions of SCCPs in China in 2014 were 3083.88tons, with emissions to the atmosphere and water accounting for 894.81tons and 2189.07tons, respectively. The largest emission source was from metalworking fluids, with total emissions of 2459.12tons, of which 756.65tons went to the atmosphere and 1702.47tons to water. Our results show that SCCP emissions were mainly concentrated in the eastern, more developed regions and that Jiangsu Province was the biggest producer in China, with total emissions of 1853.06tons, of which 562.61tons were to the atmosphere and 1290.46tons to water.

  11. Complete Non-Radioactive Operability Tests for Cladding Hull Chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Emory D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Johnson, Jared A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hylton, Tom D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brunson, Ronald Ray [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hunt, Rodney Dale [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); DelCul, Guillermo Daniel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bradley, Eric Craig [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Spencer, Barry B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-01

    Non-radioactive operability tests were made to test the metal chlorination reactor and condenser and their accessories using batch chlorinations of non-radioactive cladding samples and to identify optimum operating practices and components that need further modifications prior to installation of the equipment into the hot cell for tests on actual used nuclear fuel (UNF) cladding. The operability tests included (1) modifications to provide the desired heating and reactor temperature profile; and (2) three batch chlorination tests using, respectively, 100, 250, and 500 g of cladding. During the batch chlorinations, metal corrosion of the equipment was assessed, pressurization of the gas inlet was examined and the best method for maintaining solid salt product transfer through the condenser was determined. Also, additional accessing equipment for collection of residual ash and positioning of the unit within the hot cell were identified, designed, and are being fabricated.

  12. Modeling of residual chlorine in water distribution system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Water quality within water distribution system may vary with both location and time. Water quality models are used to predict the spatial and temporal variation of water quality throughout water system. A model of residual chlorine decay in water pipe has been developed,given the consumption of chlorine in reactions with chemicals in bulk water, bio-films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall. Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed. Model is used to predict the decay of residual chlorine in an actual distribution system. Good agreement between calculated and measured values was obtained.

  13. Characters of chlorine isotopic composition in ocean water

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Y.; Zhou, Y.; Liu, W.G.; Hong, A.; Wang, Q.; Wang, Y.; Wei, H.; Shirodkar, P.V.

    The chlorine isotopic composition of ocean water was determined using thermal ionization mass spectrometry based on the measurement of Cs sub(2) Cl sup(+) ion. The results show that the sup(37) Cl/ sup(35) Cl ratios are basically homogeneous...

  14. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfection byproducts (DBPs) at a pilot plant in Evansville, IN, which uses chlorine dioxide as a primary disinfectant. Unconventional multispectral identification techniques (gas chromatography combined with high- and low reso...

  15. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfectant byproducts (DNPS) at a pilot plant in Evansville, IN, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high- and low-resolu...

  16. Kinetics of Chlorine Decay in Water Distribution Systems

    Institute of Scientific and Technical Information of China (English)

    周建华; 薛罡; 赵洪宾; 汪永辉; 郭美芳

    2004-01-01

    A combined first and second-order model, which includes bulk decay and wall decay, was developed to describe chlorine decay in water distribution systems. In the model the bulk decay has complex relationships with total organic carbon (TOC), the initial chlorine concentration and the temperature. Except for the initial stages they can be simplified into a linear increase with TOC, a linear decrease with initial chlorine concentration and an exponential relationship with the temperature. The model also explains why chlorine decays rapidly in the initial stages. The parameters of model are determined by deriving the best fitness with experimental data. And the accuracy of model has been verified by using the experimental data and the monitoring data in a distribution system.

  17. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquife

  18. CHLORINE INACTIVATION OF CATEGORY "A" BIO-TERRORISM AGENTS

    Science.gov (United States)

    This poster presents information on the inactivation of select bioterrorist agents. Information will be presented on chlorine disinfection of vegetative cells of Brucella suis, Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis and endos...

  19. Fate of free chlorine in drinking water during distribution in premise plumbing.

    Science.gov (United States)

    Zheng, Muzi; He, Chunguang; He, Qiang

    2015-12-01

    Free chlorine is a potent oxidizing agent and has been used extensively as a disinfectant in processes including water treatment. The presence of free chlorine residual is essential for the prevention of microbial regrowth in water distribution systems. However, excessive levels of free chlorine can cause adverse health effects. It is a major challenge to maintain appropriate levels of free chlorine residual in premise plumbing. As the first effort to assessing the fate of chlorine in premise plumbing using actual premise plumbing pipe sections, three piping materials frequently used in premise plumbing, i.e. copper, galvanized iron, and polyvinyl chloride (PVC), were investigated for their performance in maintaining free chlorine residual. Free chlorine decay was shown to follow first-order kinetics for all three pipe materials tested. The most rapid chlorine decay was observed in copper pipes, suggesting the need for higher chlorine dosage to maintain appropriate levels of free chlorine residual if copper piping is used. PVC pipes exhibited the least reactivity with free chlorine, indicative of the advantage of PVC as a premise plumbing material for maintaining free chlorine residual. The reactivity of copper piping with free chlorine was significantly hindered by the accumulation of pipe deposits. In contrast, the impact on chlorine decay by pipe deposits was not significant in galvanized iron and PVC pipes. Findings in this study are of great importance for the development of effective strategies for the control of free chlorine residual and prevention of microbiological contamination in premise plumbing.

  20. Residential exposure to chlorinated hydrocarbons from groundwater contamination and the impairment of renal function-An ecological study

    Science.gov (United States)

    Chen, Hui-Ming; Wu, Ming-Tsang

    2017-01-01

    Groundwater pollution from the petrochemical industry causes serious deterioration of soil and groundwater quality and impacts on human health worldwide. However, few studies have examined the effect of residential exposure to petrochemical chlorinated hydrocarbon-contaminated groundwater on renal function impairment in humans. We conducted an ecological study to investigate the two. A polyvinyl chloride (PVC) plant was located in one of the six villages, the study area, in Kaohsiung city of southwestern Taiwan. Based on the direction of groundwater flow and previous groundwater measurements of chlorinated hydrocarbons from Taiwan Environmental Protection Bureau, we divided the six villages into highly-polluted villages, moderately-polluted villages, and a non-polluted village. All inhabitants in those six villages were invited to receive free health examinations between May-June, 2010. In total, 4,432 study subjects ≥18 yrs old were analyzed. Compared to those in the non-polluted village, subjects in highly-polluted villages had 1.89- and 1.46-fold the risk of impaired estimated glomerular filtration rate (eGFR) and proteinuria (95% CI = 1.15–1.85 and 1.09–3.28, respectively) after adjusting for other covariates. Given this relative large sample size, we found that groundwater chlorinated hydrocarbon pollution can cause kidney damage in adults. PMID:28067285

  1. Residential exposure to chlorinated hydrocarbons from groundwater contamination and the impairment of renal function-An ecological study

    Science.gov (United States)

    Chen, Hui-Ming; Wu, Ming-Tsang

    2017-01-01

    Groundwater pollution from the petrochemical industry causes serious deterioration of soil and groundwater quality and impacts on human health worldwide. However, few studies have examined the effect of residential exposure to petrochemical chlorinated hydrocarbon-contaminated groundwater on renal function impairment in humans. We conducted an ecological study to investigate the two. A polyvinyl chloride (PVC) plant was located in one of the six villages, the study area, in Kaohsiung city of southwestern Taiwan. Based on the direction of groundwater flow and previous groundwater measurements of chlorinated hydrocarbons from Taiwan Environmental Protection Bureau, we divided the six villages into highly-polluted villages, moderately-polluted villages, and a non-polluted village. All inhabitants in those six villages were invited to receive free health examinations between May-June, 2010. In total, 4,432 study subjects ≥18 yrs old were analyzed. Compared to those in the non-polluted village, subjects in highly-polluted villages had 1.89- and 1.46-fold the risk of impaired estimated glomerular filtration rate (eGFR) and proteinuria (95% CI = 1.15–1.85 and 1.09–3.28, respectively) after adjusting for other covariates. Given this relative large sample size, we found that groundwater chlorinated hydrocarbon pollution can cause kidney damage in adults.

  2. Silver-Catalyzed C(sp(3))-H Chlorination.

    Science.gov (United States)

    Ozawa, Jun; Kanai, Motomu

    2017-03-17

    A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.

  3. Bromoform production in tropical open-ocean waters: OTEC chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, E.O.; Valentine, R.

    1981-09-01

    The bromoform, and other volatile organics produced while chlorinating both the evaporator and condenser seawater during operation of the one megawatt (1 MW) OTEC-1 test facility are reported. Although many halogenated compounds might be produced as a result of chlorination, the quantitative analyses in this study focused on volatile EPA priority pollutants. Bromoform is the compound specifically recognized as a potential pollutant. Its concentration may be indicative of other halogenated species.

  4. Assessment of the risk of transporting liquid chlorine by rail

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.B.

    1980-03-01

    This report presents the risk of shipping liquid chlorine by rail. While chlorine is not an energy material, there are several benefits to studying chlorine transportation risks. First, chlorine, like energy materials, is widely used as a feedstock to industry. Second, it is the major purification agent in municipal water treatment systems and therefore, provides direct benefits to the public. Finally, other risk assessments have been completed for liquid chlorine shipments in the US and Europe, which provide a basis for comparison with this study. None of the previous PNL energy material risk assessments have had other studies for comparison. For these reasons, it was felt that a risk assessment of chlorine transportation by rail could provide information on chlorine risk levels, identify ways to reduce these risks and use previous studies on chlorine risks to assess the strengths and weaknesses of the PNL risk assessment methodology. The risk assessment methodology used in this study is summarized. The methodology is presented in the form of a risk assessment model which is constructed for ease of periodic updating of the data base so that the risk may be reevaluated as additional data become available. The report is sectioned to correspond to specific analysis steps identified in the model. The transport system and accident environment are described. The response of the transport system to accident environments is described. Release sequences are postulated and evaluated to determine both the likelihood and possible consequences of a release. Supportive data and analyses are given in the appendices. The risk assessment results are related to the year 1985 to allow a direct comparison with other reports in this series.

  5. SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; Brian02 Looney, B; Michael J. Truex; Charles J. Newell

    2006-08-16

    Over the past three decades, much progress has been made in the remediation of chlorinated solvents from the subsurface. Yet these pervasive contaminants continue to present a significant challenge to the U.S. Department of Energy (DOE), other federal agencies, and other public and private organizations. The physical and chemical properties of chlorinated solvents make it difficult to rapidly reach the low concentrations typically set as regulatory limits. These technical challenges often result in high costs and long remediation time frames. In 2003, the DOE through the Office of Environmental Management funded a science-based technical project that uses the U.S. Environmental Protection Agency's technical protocol (EPA, 1998) and directives (EPA, 1999) on Monitored Natural Attenuation (MNA) as the foundation on which to introduce supporting concepts and new scientific developments that will support remediation of chlorinated solvents based on natural attenuation processes. This project supports the direction in which many site owners want to move to complete the remediation of their site(s), that being to complete the active treatment portion of the remedial effort and transition into MNA. The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and

  6. Shock-tube pyrolysis of chlorinated hydrocarbons - Formation of soot

    Science.gov (United States)

    Frenklach, M.; Hsu, J. P.; Miller, D. L.; Matula, R. A.

    1986-01-01

    Soot formation in pyrolysis of chlorinated methanes, their mixtures with methane, and chlorinated ethylenes were studied behind reflected shock waves by monitoring the attenuation of an He-Ne laser beam. An additional single-pulse shock-tube study was conducted for the pyrolysis of methane, methyl chloride, and dichloromethane. The experiments were performed at temperatures 1300-3000 K, pressures of 0.4-3.6 bar, and total carbon atom concentrations of 1-5 x 10 to the 17th atoms cu cm. The amounts of soot produced in the pyrolysis of chlorinated hydrocarbons are larger than that of their nonchlorinated counterparts. The sooting behavior and product distribution can be generally explained in terms of chlorine-catalyzed chemical reaction mechanisms. The pathway to soot from chlorinated methanes and ethylenes with high H:Cl ratio proceeds via the formation of C2H, C2H2, and C2H3 species. For chlorinated hydrocarbons with low H:Cl ratio, the formation of C2 and its contribution to soot formation at high temperatures becomes significant. There is evidence for the importance of CHCl radical and its reactions in the pyrolysis of dichloromethane.

  7. Prompt gamma analysis of chlorine in concrete for corrosion study

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2006-02-15

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine {gamma}-rays and calcium {gamma}-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine {gamma}-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  8. Prompt gamma analysis of chlorine in concrete for corrosion study.

    Science.gov (United States)

    Naqvi, A A; Nagadi, M M; Al-Amoudi, O S B

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples.

  9. Chlorine dioxide project allows Stora to clean up, use hardwoods

    Energy Technology Data Exchange (ETDEWEB)

    Butters, G.

    1988-10-01

    Effluent fouling into the Strait of Canso between Nova Scotia mainland and Cape Breton Island has caused Stora Forest Industries Ltd. to develop a $5.6 million solution to its chlorine and acid problems. In 1987, Stora produced about 160,000 tonnes of market pulp where their resource base increasingly consisted of hardwood. The company uses hardwood chips for a growing percentage of its annual pulp production and for its hog fuel boiler, but became faced with having to use more local hardwoods which contributes to the resin problem. Their solution was to construct a 12-tpd chlorine dioxide generator, a process using dry sodium chlorate added to concentrated H/sub 2/SO/sub 4/, The products are chlorine dioxide and highly concentrated sulphuric acid resulting from the elimination of water at the starting point. This will eliminate the acid effluent from the generator and the sulphuric acid will be recycled to the top of the chlorine dioxide generation process. In the new process, ClCO/sub 2/ replaces 70% of the chlorine in the first stage, with 100% substitution a goal. In addition to eliminating the chlorine, other benefits include an increase in pulp production, a nominal increase in pulp strength, lower production costs, and an economic incentive to harvest the area's mixed-wood stands.

  10. Zebra mussel control using periodic chlorine dioxide treatments

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Merdosia, IL (United States); Crone, D. [Illinois Power Company, Alton, IL (United States)] [and others

    1996-08-01

    This paper summarizes the EPRI report (TR-105202) on the same topic as well as presents changes in current thinking on the suitability (applicability) of chlorine dioxide for fouling control. Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois and one in Indiana. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the three utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received applications in July 1993, January, April, May, July, and September 1994. The Gallagher Station, on the Ohio River, was treated in July and October 1994. Chlorine dioxide was generated on-site and injected into the water intake structure. Both cooling and service water systems were treated at the facilities. 6 refs., 13 figs.

  11. Chlorobenzene outputs from combustion of chlorinated organic and inorganic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Green, A.E.S.; Vitali, J.A.; Miller, T.L. [Univ. of Florida, Gainesville, FL (United States)

    1994-12-31

    The authors consider the gas phase formation of chlorinated benzenes and phenols as precursors of chlorinated dioxins and furans from the combustion of solid fuels containing organically bound chlorine. The model investigated is intended to apply to the combustion of medical waste, municipal waste and coals containing chlorine. Assuming a temperature-time profile drawn from incinerator experiments, the authors use kinetic modeling with known reaction rates to further investigate four models of chlorinated benzene formation. Since reaction rates for most chlorination processes are now known, the authors choose simple systems of reaction rates that yield outputs that can be made approximately compatible with results of the Pittsfield-Vicon incinerator and Clean Combustion Technology Laboratory experiments. The authors also consider recent measurements of HCI emissions from crematoria and the implication of this work with respect to the benefits of material substitution in medical and municipal waste incineration. These benefits should also accompany the dechlorination of coals. The authors note the disparity between the prevailing USA position and the emerging position of Germany on the issue of halogenated plastics. The authors also note that Europe and Asia are beginning to address solid fuel issues as a consolidated discipline. This pattern should be helpful in broadening the understanding of solid fuels combustion processes and in ferreting out erroneous data and conclusions. This is important in view of the recent concern about the role of low dioxin exposure levels on fetal development and the immune system.

  12. Disinfection of swine wastewater using chlorine, ultraviolet light and ozone.

    Science.gov (United States)

    Macauley, John J; Qiang, Zhimin; Adams, Craig D; Surampalli, Rao; Mormile, Melanie R

    2006-06-01

    Veterinary antibiotics are widely used at concentrated animal feeding operations (CAFOs) to prevent disease and promote growth of livestock. However, the majority of antibiotics are excreted from animals in urine, feces, and manure. Consequently, the lagoons used to store these wastes can act as reservoirs of antibiotics and antibiotic-resistant bacteria. There is currently no regulation or control of these systems to prevent the spread of these bacteria and their genes for antibiotic resistance into other environments. This study was conducted to determine the disinfection potential of chlorine, ultraviolet light and ozone against swine lagoon bacteria. Results indicate that a chlorine dose of 30 mg/L could achieve a 2.2-3.4 log bacteria reduction in lagoon samples. However, increasing the dose of chlorine did not significantly enhance the disinfection activity due to the presence of chlorine-resistant bacteria. The chlorine resistant bacteria were identified to be closely related to Bacillus subtilis and Bacillus licheniformis. A significant percentage of lagoon bacteria were not susceptible to the four selected antibiotics: chlortetracycline, lincomycin, sulfamethazine and tetracycline (TET). However, the presence of both chlorine and TET could inactivate all bacteria in one lagoon sample. The disinfection potential of UV irradiation and ozone was also examined. Ultraviolet light was an effective bacterial disinfectant, but was unlikely to be economically viable due to its high energy requirements. At an ozone dose of 100 mg/L, the bacteria inactivation efficiency could reach 3.3-3.9 log.

  13. Purification of highly chlorinated dioxins degrading enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, K.; Furuichi, T.; Koike, K.; Kuboshima, M. [Hokkaido Univ. (Japan). Division of Environment Resource Engineering, Graduate School of Engineering

    2004-09-15

    Soil contamination caused by dioxins in and around sites of incinerators for municipal solid waste (MSW) is a concern in Japan. For example, scattering wastewater from a wet gas scrubber at an MSW incinerator facility in Nose, Osaka caused soil and surface water contamination. The concentration of dioxins in the soil was about 8,000 pg-TEQ/g. Other contamination sites include soils on which fly ash has been placed directly or improperly stored and landfill sites that have received bottom and fly ash over a long period. Some countermeasures are required immediately at these dioxins-contaminated sites. We have previously developed bioreactor systems for dioxin-contaminated water and soil. We have shown that a fungus, Pseudallescheria boydii (P. boydii), isolated from activated sludge treating wastewater that contained dioxins, has the ability to degrade highly chlorinated dioxins. A reaction product of octachlorinated dibenzo-p-dioxin (OCDD) was identified as heptachlorinated dibenzo-p-dioxin. Therefore, one of the pathways for degradation of OCDD by this fungus was predicted to be as follows: OCDD is transformed by dechlorination and then one of the remaining aromatic rings is oxidized. To apply P. boydii to on-site technologies (e.g., bioreactor systems), as well as in situ technologies, enzyme treatment using a dioxin-degrading enzyme from P. boydii needs to be developed because P. boydii is a weak pathogenic fungus, known to cause opportunistic infection. As a result, we have studied enzyme purification of nonchlorinated dioxin, namely, dibenzo-pdioxin (DD). However, we did not try to identify enzymes capable of degrading highly chlorinated dioxins. This study has elucidated a method of enzyme assay for measuring OCDD-degrading activity, and has attempted to purify OCDD-degrading enzymes from P. boydii using enzyme assay. In addition, as first step toward purifying 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 2,3,7,8-TCDD degradation tests were carried out

  14. Synergistic effect between UV and chlorine (UV/chlorine) on the degradation of carbamazepine: Influence factors and radical species.

    Science.gov (United States)

    Wang, Wen-Long; Wu, Qian-Yuan; Huang, Nan; Wang, Ting; Hu, Hong-Ying

    2016-07-01

    For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl(-) and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min(-1) and that by Cl decreased from 0.40 to 0.11 min(-1). The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10(10) M(-1) s(-1). Anions of HCO3(-) (1-50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl(-) did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14-0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione.

  15. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju, E-mail: jjgeng@nju.edu.cn; Ren, Hongqiang, E-mail: hqren@nju.edu.cn; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L{sup −1}. The transformation kinetic data for ARGs removal (log C{sub 0} / C) followed the second-order reaction kinetic model with FC dosage (R{sup 2} = 0.6829–0.9999) and contact time (R{sup 2} = 0.7353–8634), respectively. Higher ammonia nitrogen (NH{sub 3}–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl{sub 2}:NH{sub 3}–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm{sup −2}, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - Highlights: • Chlorine is more effective than UV irradiation in removing ARGs from MWTP effluent. • The chlorination reaction followed the second-order reaction kinetic model. • Higher NH{sub 3}–N contents result in lower ARGs removal in the chlorination process. • FC is more effective than CC on the inactivation of ARGs. • UV irradiation followed by chlorination shows high efficiency in removing ARGs.

  16. Site-selective photofragmentation of chlorinated polymeric films observed around the chlorine K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Arantes, C., E-mail: csilva@inmetro.gov.br [Divisão de Metrologia de Materiais, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Xerém 25250-020, Duque de Caxias, RJ (Brazil); Mendes, L.A.V. [Instituto de Física, Universidade Federal da Bahia, Ondina, 40210-340 Salvador, BA (Brazil); Pinho, R.R. [Departamento de Física-ICE, Universidade Federal de Juiz de Fora, Campus Universitário, 36036-330 Juiz de Fora, MG (Brazil); Ferreira, M. [PEMM/COPPE, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-972 Rio de Janeiro, RJ (Brazil); Souza, G.G.B. de; Rocha, A.B.; Rocco, M.L.M. [Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, Ilha do Fundão, 21941-909 Rio de Janeiro, RJ (Brazil)

    2013-03-29

    Highlights: ► PVC and PVDC were studied by PSID and NEXAFS techniques at the Chlorine 1s-edge. ► PVC film presented isotope ratio of 3:1 in the PSID spectrum. ► Cl{sup +} ion yield curves reproduce the photoabsorption spectrum for both polymers. ► Site-selectivity of C–Cl bond breaking due to an efficient spectator Auger decay. - Abstract: Photon stimulated ion desorption (PSID) and Near-edge X-ray absorption fine structure (NEXAFS) studies have been performed on poly(vinyl chloride) (PVC) and poly(vinyl dichloride) (PVDC) around the chlorine 1s-edge. Experiments were performed using a synchrotron source operating in the single-bunch mode and a time-of-flight mass spectrometry for ion analysis. Cl{sup +} ion yields, as a function of the photon energy, reproduce the photoabsorption spectrum, showing significant increase at the 1s-resonance. Edge-jump ratios, defined as the ratio between edge-jumps (intensity ratio of the yields between above and below the absorption edge) of two different transitions, for Cl{sup +} ion yields were much higher than the equivalent electron yields, indicating site-selectivity in C–Cl bond breaking for both polymers, as a result of efficient spectator Auger decay. The expected isotope ratio of 3:1 for chlorine was measured for PVC. The interpretation of the NEXAFS spectrum was assisted by quantum mechanical calculations at a multireference perturbation theory level.

  17. Ficusmicrochlorin A-C, two new methoxy lactone chlorins and an anhydride chlorin from the leaves of Ficus microcarpa.

    Science.gov (United States)

    Lin, Huan-You; Chiu, Hsi-Lin; Lu, Te-Ling; Tzeng, Chih-Ying; Lee, Tzong-Huei; Lee, Ching-Kuo; Shao, Yi-Yuan; Chen, Chiy-Rong; Chang, Chi-I; Kuo, Yueh-Hsiung

    2011-01-01

    Two new methoxy lactone chlorins ficusmicrochlorin A (1) and ficusmicrochlorin B (2), and one new anhydride chlorin ficusmicrochlorin C (3), along with eight known pheophytins were isolated from the leaves of Ficus microcarpa. Their structures were determined by the extensive 1D- and 2D-NMR techniques. New pheophytin compound was rarely obtained from natural sources. In the past ten years, only three new natural pheophytins were characterized.

  18. Transformation of cefazolin during chlorination process: products, mechanism and genotoxicity assessment.

    Science.gov (United States)

    Li, Liping; Wei, Dongbin; Wei, Guohua; Du, Yuguo

    2013-11-15

    Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during chlorination process.

  19. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Science.gov (United States)

    Vidakovic-Koch, Tanja; Martinez, Isai Gonzalez; Kuwertz, Rafael; Kunz, Ulrich; Turek, Thomas; Sundmacher, Kai

    2012-01-01

    Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl− crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized. PMID:24958294

  20. Chlorinated hydrocarbon contaminants in arctic marine mammals.

    Science.gov (United States)

    Norstrom, R J; Muir, D C

    1994-09-16

    By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals. Except in the Russian Arctic, data have now been obtained on the temporospatial distribution of PCBs and other contaminants in ringed seal, beluga and polar bear. Contaminants in narwhal (Monodon monoceros) have also now been measured. On a fat weight basis, the sum of DDT-related compounds (S-DDT) and PCB levels are lowest in walrus (St. Lawrence and ringed seal in the Baltic Sea, indicate that overall contamination of the Arctic marine ecosystem is 10-50 times less than the most highly contaminated areas in the northern hemisphere temperate latitude marine environment. Geographic distribution of residue levels in polar bears indicates a gradual increase from Alaska east to Svalbard, except PCB levels are significantly higher in eastern Greenland and Svalbard. Information on temporal trends is somewhat contradictory.(ABSTRACT TRUNCATED AT 400 WORDS)

  1. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Directory of Open Access Journals (Sweden)

    Ulrich Kunz

    2012-07-01

    Full Text Available Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized.

  2. Development of a Site-Specific Kinetic Model for Chlorine Decay and the Formation of Chlorination By-Products in Seawater

    Directory of Open Access Journals (Sweden)

    Suhur Saeed

    2015-07-01

    Full Text Available Chlorine is used commonly to prevent biofouling in cooling water systems. The addition of chlorine poses environmental risks in natural systems due to its tendency to form chlorination by-products (CBPs when exposed to naturally-occurring organic matter (NOM. Some of these CBPs can pose toxic risks to aquatic and benthic species in the receiving waters. It is, therefore, important to study the fate of residual chlorine and CBPs to fully understand the potential impacts of chlorination to the environment. The goal of this study was to develop improved predictions of how chlorine and CBP concentrations in seawater vary with time, chlorine dose and temperature. In the present study, chlorination of once-through cooling water at Ras Laffan Industrial City (RLIC, Qatar, was studied by collecting unchlorinated seawater from the RLIC cooling water system intake, treating it with chlorine and measuring time series of chlorine and CBP concentrations. Multiple-rate exponential curves were used to represent fast and slow chlorine decay and CBP formation, and site-specific chlorine kinetic relationships were developed. Through extensive analysis of laboratory measurements, it was found that only some of the control parameters identified in the literature were important for predicting residual chlorine and CBP concentrations for this specific location. The new kinetic relationships were able to significantly improve the predictability and validity of Generalized Environmental Modeling System for Surfacewaters (GEMSS-chlorine kinetics module (CKM, a three-dimensional hydrodynamic and chlorine kinetics and transport model when applied for RLIC outfall studies using actual field measurements.

  3. Sequential disinfection of E. coli O157:H7 on shredded lettuce leaves by aqueous chlorine dioxide, ozonated water, and thyme essential oil

    Science.gov (United States)

    Singh, Nepal; Singh, Rakesh K.; Bhunia, Arun K.; Stroshine, Richard L.; Simon, James E.

    2001-03-01

    There have been numerous studies on effectiveness of different sanitizers for microbial inactivation. However, results obtained from different studies indicate that microorganism cannot be easily removed from fresh cut vegetables because of puncture and cut surfaces with varying surface topographies. In this study, three step disinfection approach was evaluated for inactivation of E. coli O157:H7 on shredded lettuce leaves. Sequential application of thyme oil, ozonated water, and aqueous chlorine dioxide was evaluated in which thyme oil was applied first followed by ozonated water and aqueous chlorine dioxide. Shredded lettuce leaves inoculated with cocktail culture of E. coli O157:H7 (C7927, EDL 933 and 204 P), were washed with ozonated water (15 mg/l for 10min), aqueous chlorine dioxide (10 mg/l,for 10min) and thyme oil suspension (0.1%, v/v for 5min). Washing of lettuce leaves with ozonated water, chlorine dioxide and thyme oil suspension resulted in 0.44, 1.20, and 1.46 log reduction (log10 cfu/g), respectively. However, the sequential treatment achieved approximately 3.13 log reductions (log10 cfu/g). These results demonstrate the efficacy of sequential treatments in decontaminating shredded lettuce leaves containing E. coli O157:H7.

  4. Comparison of chlorine and chlorine dioxide toxicity of fathead minnows and bluegill

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.; Soracco, R.J.; Mayack, L.A.; Shealy, R.L.; Broadwell, T.L.; Steffen, R.F.

    1983-01-01

    The comparative toxicity of total residual chlorine (TRC) and chlorine dioxide (ClO/sub 2/) was evaluated by conducting 96 h flow-through bioassays with three types of fish. The fish were subjected to an intermittent exposure regime in which biocide residuals were present for approximately 2-h periods beginning at 0, 24, 48 and 72 h into the tests. These conditions simulated the antifouling procedure (1 h day/sup -1/ biocide addition) used to control biofouling of nuclear reactor heat exchangers at the Savannah River Plant near Aiken, South Carolina. LC/sub 50/ values showed that ClO/sub 2/ was approximately 2 to 4 times more toxic than TRC to: (1) juvenile and 1-year-old fathead minnows (Pimphales promelas); and (2) young-of-the-year bluegill (Lepomis macrochirus). The TRC mean 96-h LC/sub 50/ values were: 0.08 mg l/sup -1/ for juvenile fathead minnows, 0.35 mg l/sup -1/ for adult fathead minnows and 0.44 mg l/sup -1/ for young-of-the-year bluegills. The ClO/sub 2/ mean LC/sub 50/ values were: 0.02 mg l/sup -1/ for juvenile fathead minnows, 0.17 mg l/sup -1/ for adult fathead minnows and 0.15 mg l/sup -1/ for young-of-the-year bluegills. 31 references, 1 figure, 3 tables.

  5. Chlorination of tramadol: Reaction kinetics, mechanism and genotoxicity evaluation.

    Science.gov (United States)

    Cheng, Hanyang; Song, Dean; Chang, Yangyang; Liu, Huijuan; Qu, Jiuhui

    2015-12-01

    Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products.

  6. CHLORINATION OF AMINO ACIDS: REACTION PATHWAYS AND REACTION RATES.

    Science.gov (United States)

    How, Zuo Tong; Linge, Kathryn; Busetti, Francesco; Joll, Cynthia A

    2017-03-15

    Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected by-products. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modelling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4x104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9x102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0x10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3x10-4 s-1) and N-chloroisobutyraldimine (1.2x10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odour threshold concentration, resulting in aesthetic challenges and an unknown health risk.

  7. Electrochemical reduction characteristics and the mechanism of chlorinated hydrocarbons at the copper electrode

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; GAO Tingyao; ZHOU Rongfeng; MA Lumin

    2007-01-01

    The electrochemical reduction characteristies of chlorinated hyrdrocarbons were investigated by cyclic voltammetry technique.The reduction mechanism and activity of the chlorinated hydrocarbons at the copper electrode were explored.The relationship between the structure of chlorinated hydrocarbons and their reductive activity were discussed.The experimental results showed that chlorinated alkanes and a portion of chlorinated aromatic hydrocarbons could be reduced directly at the copper electrode.However,chlorinated aromatic hydrocarbons were not easy to reduce at the copper electrode.The results provided a theoretical basis for the catalyzed iron inner electrolysis method.

  8. Study on metal corrosion caused by chlorine dioxide of various purities

    Institute of Scientific and Technical Information of China (English)

    崔崇威; 黄君礼; 许晶

    2004-01-01

    Weight lost method was used to comparatively study the corrosion behavior of four different metals under the dosage of chlorine dioxide, chlorine and their mixture respectively. The experimental results indicated that chlorine causes the most serious corrosion of carbon steel, and the higher the concentration of chlorine, the more serious the corrosion. On the contras, metals corrosion is the least serious in the case of chlorine dioxide.The results further revealed that chlorine dioxide is the most effective water treatment reagent, making it the best choice to use extensively in circulated cooling water disinfection and corrosion control.

  9. Chlorine solubility in evolved alkaline magmas

    Directory of Open Access Journals (Sweden)

    M. R. Carroll

    2005-06-01

    Full Text Available Experimental studies of Cl solubility in trachytic to phonolitic melts provide insights into the capacity of alkaline magmas to transport Cl from depth to the earth?s surface and atmosphere, and information on Cl solubility variations with pressure, temperature and melt or fluid composition is crucial for understanding the reasons for variations in Cl emissions at active volcanoes. This paper provides a brief review of Cl solubility experiments conducted on a range of trachytic to phonolitic melt compositions. Depending on the experimental conditions the melts studied were in equilibrium with either a Cl-bearing aqueous fluid or a subcritical assemblage of low- Cl aqueous fluid + Cl-rich brine. The nature of the fluid phase(s was identified by examination of fluid inclusions present in run product glasses and the fluid bulk composition was calculated by mass balance. Chlorine concentrations in the glass increase with increasing Cl molality in the fluid phase until a plateau in Cl concentration is reached when melt coexists with aqueous fluid + brine. With fluids of similar Cl molality, higher Cl concentrations are observed in peralkaline phonolitic melts compared with peraluminous phonolitic melts; overall the Cl concentrations observed in phonolitic and trachytic melts are approximately twice those found in calcalkaline rhyolitic melts under similar conditions. The observed negative pressure dependence of Cl solubility implies that Cl contents of melts may actually increase during magma decompression if the magma coexists with aqueous fluid and Cl-rich brine (assuming melt-vapor equilibrium is maintained. The high Cl contents (approaching 1 wt% Cl observed in some melts/glasses from the Vesuvius and Campi Flegrei areas suggest saturation with a Cl-rich brine prior to eruption.

  10. Inactivation of antibiotic resistance genes in municipal wastewater effluent by chlorination and sequential UV/chlorination disinfection.

    Science.gov (United States)

    Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Zhang, Yan; Ding, Lili; Xu, Ke

    2015-04-15

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p=0.007-0.014, n=6),as well as contact time (p=0.0001, n=10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30-1.49 logs) could be achieved at FC dosage of 30 mg L(-1). The transformation kinetic data for ARGs removal (log C0/C) followed the second-order reaction kinetic model with FC dosage (R(2)=0.6829-0.9999) and contact time (R(2)=0.7353-8634), respectively. Higher ammonia nitrogen (NH3-N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl2:NH3-N ratio was over 7.6:1, a significant reduction of ARGs (1.20-1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36-0.40 at a fluence of 249.5 mJ cm(-2), which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters.

  11. Rapid Determination of HAAs Formation Potential of the Reaction of Humic Acid with Chlorine or Chlorine Dioxide

    Institute of Scientific and Technical Information of China (English)

    ZHU Zhi-liang; GE Yuan-xin; ZHANG Rong-hua; MA Hong-mei; HAO Jian-fu

    2007-01-01

    On the basis of gas chromatography(GC) coupled with a short capillary column and an electron capture detector(ECD), a simple and rapid method for the determination of five haloacetic acids(HAAs) in drinking water was developed by the optimization of derivation conditions and the modification of gas chromatographic program. HAAs formation potential(HAAFP) of the reaction of humic acid with chlorine was determined via this method. The major advantages of the method are the simplicity of chromatographic temperature program and the short run time of GC. Dichloroacetic acid(DCAA) and Trichloroacetic acid(TCAA), which were detected in the determination of HAAFP, were rapidly formed in the first 72 h of the reaction of humic acid with chlorine. HAAFP of the reaction of humic acid with chlorine increased with the increase in the concentrations of humic acid and chlorine. The average HAAFP of the reaction of humic acid with chlorine was 39.9 μg/mg TOC under the experimental conditions. When the concentration of humic acid was 4 mg/L, the concentration of HAAs, which were produced in the reaction of humic acid with chorine, may exceed MCL of 60 μg/L HAAs as the water quality standards for urban water supply of China and the first stage of US EPA disinfection/disinfection by-products(D/DBP) rule; when the concentration of humic acid was 2 mg/L, the concentration of HAAs may exceed MCL of 30 μg/L HAAs for the second stage of US EPA D/DBP rule. When humic acid was reacted with chlorine dioxide, only DCAA was detected with a maximum concentration of 3.3 μg/L at a humic acid content of 6 mg/L. It was demonstrated that the substitution of chlorine dioxide for chorine may entirely or partly control the formation of HAAs and effectively reduce the health risk associated with disinfected drinking water.

  12. Chlorinated organic pesticides in marketed food: Barcelona, 2001-06

    Energy Technology Data Exchange (ETDEWEB)

    Fontcuberta, M. [Agencia de Salut Publica de Barcelona, ASPB, Public Health Agency of Barcelona, Av Drassanes 13, 08001 Barcelona (Spain)], E-mail: mfontcub@aspb.es; Arques, J.F.; Villalbi, J.R.; Martinez, M.; Centrich, F.; Serrahima, E.; Pineda, L.; Duran, J.; Casas, C. [Agencia de Salut Publica de Barcelona, ASPB, Public Health Agency of Barcelona, Av Drassanes 13, 08001 Barcelona (Spain)

    2008-01-15

    This paper reports concentration levels of 22 chlorinated organic compounds (both primary compounds and metabolites) in food marketed in the city of Barcelona (Catalonia, Spain) in 2001-06. Samples included meat products, fish and seafood, eggs, milk and dairy, vegetal oils, cereal products and derivates, vegetables, fresh fruits, dry fruits, spices, formula and baby food, tea and wine. Levels of chlorinated organic compounds were determined by gas chromatography with selective detectors: electron capture (ECD), flame photometric (FPD) and confirmation with mass-spectrometry. Chlorinated organic pesticides were detected in 7 of the 1,484 samples analyzed in the 2001-06 period (0.5%): 1 dairy product, 1 fruit, 1 olive oil and 4 vegetables. Specific pesticides detected are lindane and endosulfan {alpha}, {beta} or sulphate. A decrease in both the proportion of samples with detectable residues and in the variety of chlorinated pesticides found is visible when comparing these results with those of the previous 1989-2000 period. These results suggest the gradual disappearance of regulated chlorinated organic pesticides as a consequence of the growing worldwide implementation of current regulatory agreements.

  13. Intra- and intermembrane distribution of chlorin e6 derivatives

    Science.gov (United States)

    Zorin, Vladimir P.; Zorina, Tatyana E.; Mikhalovsky, Iosif S.; Khludeyev, Ivan I.

    1995-01-01

    The parameters of chlorin e6 and trimethylester of chlorin e6 incorporation and distribution in suspensions of unilamellar liposomes of DMPC, DPPC, and DSPC, as well as efficiency of the pigment redistribution from liposomes to cellular membranes have been studied. Determination of the fraction of pigments' fluorescence which is accessible to quenching by a watersoluble quencher indicates that for both chlorins the outer monolayer of the liposomal membrane is more populated than the inner one. Gel-liquid crystalline phase transition induces a shift of a part of the pigments' molecules toward the inner monolayer. By means of ultrafiltration technique it is shown that chlorins binding to liposomal membrane occurs as partitioning between water and lipid phases. The partition coefficient is affected strongly by the type of pigment, the phase state of the lipid bilayer. Similar results were obtained when the influence of the physical state of the lipid bilayer on the rate of chlorins redistribution from liposomes to cellular membrane was studied. These findings show that diffusive mobility of the sensitizer in suspensions of cellular and model membranes is a complex process which is dependent on structural features of both the pigment and its biological carriers.

  14. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina); Barbosa, Lucía [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo Parque General San Martín, Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina)

    2014-11-15

    Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl{sub 2}–N{sub 2} flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al{sub 2}O{sub 3} (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl{sub 2} atmosphere of the MgO–Al{sub 2}O{sub 3} mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C.

  15. Coagulation properties of anelectrochemically prepared polyaluminum chloride containing active chlorine

    Institute of Scientific and Technical Information of China (English)

    HU Chengzhi; LIU Huijuan; QU Jiuhui

    2006-01-01

    With high content of the Al13 species and the active chloride, an electrochemically prepared polyaluminum chloride (E-PACl) presents integrated efficiency of coagulation and oxidation. The coagulation properties of E-PACl were systemically investigated through jar tests in the various water quality conditions. The active chlorine in E-PACl can significantly influence the coagulation behavior due to the active chlorine preoxidation, which can change the surface charge characteristic of organic matter (OM) in water. The active chlorine preoxidation could improve the E-PACl coagulation efficiency if the water possessed the characteristics of relatively low OM content (2 mg/L) and high hardness (278 mg CaCO3/L). In the water with medium content of OM (5 mg/L), dosage would be a crucial factor to decide whether the active chlorine in E-PACl aided coagulation process or not. Comparing with alkaline condition, active chlorine would show a more significant influence on the coagulation process in acidic region.

  16. Transgenic plants and associated bacteria for phytoremediation of chlorinated compounds.

    Science.gov (United States)

    Van Aken, Benoit; Doty, Sharon Lafferty

    2010-01-01

    Phytoremediation is the use of plants for the treatment of environmental pollution, including chlorinated organics. Although conceptually very attractive, removal and biodegradation of chlorinated pollutants by plants is a rather slow and inefficient process resulting in incomplete treatment and potential release of toxic metabolites into the environment. In order to overcome inherent limitations of plant metabolic capabilities, plants have been genetically modified, following a strategy similar to the development of transgenic crops: genes from bacteria, fungi, and mammals involved in the metabolism of organic contaminants, such as cytochrome P-450 and glutathione S-transferase, have been introduced into higher plants, resulting in significant improvement of tolerance, removal, and degradation of pollutants. Recently, plant-associated bacteria have been recognized playing a significant role in phytoremediation, leading to the development of genetically modified rhizospheric and endophytic bacteria with improved biodegradation capabilities. Transgenic plants and associated bacteria constitute a new generation of genetically modified organisms for efficient and environmental-friendly treatment of polluted soil and water. This review focuses on recent advances in the development of transgenic plants and bacteria for the treatment of chlorinated pollutants, including chlorinated solvents, polychlorinated phenols, and chlorinated herbicides.

  17. Application of chlorine dioxide as an oilfield facilities treatment fluid

    Energy Technology Data Exchange (ETDEWEB)

    Romaine, J.; Strawser, T.G.; Knippers, M.L.

    1995-11-01

    Both mechanical and chemical treatments are used to clean water flood injection distribution systems whose efficiency has been reduced as a result of plugging material such as iron sulfide sludge. Most mechanical treatments rely on uniform line diameter to be effective, while chemical treatments require good contact with the plugging material for efficient removal. This paper describes the design and operation of a new innovative application using chlorine dioxide for the removal of iron sulfide sludge from water flood injection distribution systems. This technology has evolved from the use of chlorine dioxide in well stimulation applications. The use of chlorine dioxide for continuous treatment of injection brines will also be discussed. Exxon USA`s Hartzog Draw facility in Gillette, Wyoming was the site for the application described. 4,500 barrels of chlorine dioxide was pumped in three phases to clean sixty-six miles of the water flood distribution system. Results indicate that chlorine dioxide was effective in cleaning the well guard screens, the injection lines, frac tanks used to collect the treatment fluids and the injection wells.

  18. MECHANISM OF CHLORATE FORMATION IN CHLORINE DIOIXDE DELIGNIFICATION

    Institute of Scientific and Technical Information of China (English)

    Byung-Ho Yoon; Li-Jun Wang; Se-Jong Kim

    2004-01-01

    The effect of pH on chlorate formation during chlorine dioxide delignification of oxygen delignified kraft pulp was studied. Chlorate formation was found to increase slightly when pH was increased from 1.8 to 2.5, further increase of pH decreased chlorate formation.The above phenomenon is explained by the combination of two mechanisms, one by the reaction between hypochlorous acid and chlorite, another by the effect of chlorine on the regeneration of chlorine dioxide. The first mechanism suggests that chlorate formation is highly dependent on HCIO concentration which decreases with increasing pH and causes chlorate formation to behave in the same trend. The second mechanism suggests that chlorine favors the regeneration of chlorine dioxide while HCIO favors chlorate formation, thus lowering the pH from about 4 to the acidic end should decreases chlorate formation. The two opposite effects lead to the maximum formation of chlorate at around pH 2.5.

  19. Biofouling control: Bacterial quorum quenching versus chlorination in membrane bioreactors.

    Science.gov (United States)

    Weerasekara, Nuwan A; Choo, Kwang-Ho; Lee, Chung-Hak

    2016-10-15

    Biofilm formation (biofouling) induced via cell-to-cell communication (quorum sensing) causes problems in membrane filtration processes. Chorine is one of the most common chemicals used to interfere with biofouling; however, biofouling control is challenging because it is a natural process. This study demonstrates biofouling control for submerged hollow fiber membranes in membrane bioreactors by means of bacterial quorum quenching (QQ) using Rhodococcus sp. BH4 with chemically enhanced backwashing. This is the first trial to bring QQ alongside chlorine injection into practice. A high chlorine dose (100 mg/L as Cl2) to the system is insufficient for preventing biofouling, but addition of the QQ bacterium is effective for disrupting biofouling that cannot be achieved by chlorination alone. QQ reduces the biologically induced metal precipitate and extracellular biopolymer levels in the biofilm, and biofouling is significantly delayed when QQ is applied in addition to chlorine dosing. QQ with chlorine injection gives synergistic effects on reducing physically and chemically reversible fouling resistances while saving substantial filtration energy. Manipulating microbial community functions with chemical treatment is an attractive tool for biofilm dispersal in membrane bioreactors.

  20. Chlorination byproducts, their toxicodynamics and removal from drinking water.

    Science.gov (United States)

    Gopal, Krishna; Tripathy, Sushree Swarupa; Bersillon, Jean Luc; Dubey, Shashi Prabha

    2007-02-01

    No doubt that chlorination has been successfully used for the control of water borne infections diseases for more than a century. However identification of chlorination byproducts (CBPs) and incidences of potential health hazards created a major issue on the balancing of the toxicodynamics of the chemical species and risk from pathogenic microbes in the supply of drinking water. There have been epidemiological evidences of close relationship between its exposure and adverse outcomes particularly the cancers of vital organs in human beings. Halogenated trihalomethanes (THMs) and haloacetic acids (HAAs) are two major classes of disinfection byproducts (DBPs) commonly found in waters disinfected with chlorine. The total concentration of trihalomethanes and the formation of individual THM species in chlorinated water strongly depend on the composition of the raw water, on operational parameters and on the occurrence of residual chlorine in the distribution system. Attempts have been made to develop predictive models to establish the production and kinetics of THM formations. These models may be useful for operational purposes during water treatment and water quality management. It is also suggested to explore some biomarkers for determination of DBP production. Various methods have been suggested which include adsorption on activated carbons, coagulation with polymer, alum, lime or iron, sulfates, ion exchange and membrane process for the removal of DBPs. Thus in order to reduce the public health risk from these toxic compounds regulation must be inforced for the implementation of guideline values to lower the allowable concentrations or exposure.

  1. Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Al-Gabr, Hamid Mohammad [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); State Key Laboratory of Environmental Sciences, and Key Laboratory of Ministry of Education for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005 (China); Zheng, Tianling [State Key Laboratory of Environmental Sciences, and Key Laboratory of Ministry of Education for Coast and Wetland Ecosystems, School of Life Sciences, Xiamen University, Xiamen 361005 (China); Yu, Xin, E-mail: xyu@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China)

    2013-10-01

    The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log{sub 10} control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log{sub 10} reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. - Highlights: • As a disinfectant, chlorine is more effective than UV in inactivating Aspergillus flavus. • As a combined method, UV irradiation followed by chlorination shows high efficiency. • UV irradiation can improve effectiveness of chlorination in reducing Aspergillus flavus.

  2. Transformation of cefazolin during chlorination process: Products, mechanism and genotoxicity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liping, E-mail: lisaleercees807@yahoo.cn; Wei, Dongbin, E-mail: weidb@rcees.ac.cn; Wei, Guohua, E-mail: wgh@rcees.ac.cn; Du, Yuguo, E-mail: duyuguo@rcees.ac.cn

    2013-11-15

    Highlights: • Base-catalyzed electrophilic substitution occurred in cefazolin chlorination. • Oxidation of thioether in cefazolin was found in chlorination process. • The pH conditions impacted on the occurrence of reaction types. • Genotoxicity had an elevation after chlorination of cefazolin. • Reaction pathways of cefazolin chlorination were replayed in surface water matrix. -- Abstract: Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during chlorination process.

  3. Enhanced reductive dechlorination in clay till contaminated with chlorinated solvents

    DEFF Research Database (Denmark)

    Damgaard, Ida

    Chlorinated solvents are among the most frequently found contaminants in groundwater. In fractured media, chlorinated ethenes and ethanes are transported downwards through preferential pathways with subsequent diffusion into the sediment matrix. Due to slow back diffusion it can serve as a long...... term secondary source that can leach to the underlying aquifer. As some of the chlorinated solvents and their degradation products are toxic and carcinogenic, remediation technologies applicable in low permeability settings are needed. Enhanced reductive dechlorination (ERD) has been proven efficient...... and ethanes in clay till (Vadsbyvej) revealed a very complex system where diffusion, biotic and abiotic degradation processes occurred simultaneously. High resolution sub sampling with combined use of chemical analysis, molecular microbial tools and CSIA was necessary to identify both biotic and abiotic...

  4. The geochemistry of stable chlorine and bromine isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Eggenkamp, Hans [Onderzock and Beleving, Bussum (Netherlands)

    2014-11-01

    First book solely dedicated to the geochemistry of chlorine and bromine isotopes. Detailed description of analytical techniques, including their advantages and disadvantages. Indication of research fields where measurement of these isotopes is especially useful. This book provides detailed information on the history, analysis and applications of chlorine and bromine isotope geochemistry. Chlorine and bromine are geochemically unique as they prefer to exist as single charged negative ions. For this reason isotope fractionation reflects mostly processes that are not related to changes in the redox state and this fractionation is generally modest. The book will describe the processes that are most easily detected using these isotopes. Also isotope variations, and processes that cause them, measured in oxidised species such as perchlorates and in organic molecules will be described in this book.

  5. Survey of potential chlorine production processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-01

    This report is part of the ongoing study of industrial electrochemical processes for the purpose of identifying methods of improving energy efficiencies. A computerized literature search of past and current chlorine generation methods was performed to identify basic chlorine production processes. Over 200 pertinent references are cited involving 20 separate and distinct chlorine processes. Each basic process is evaluated for its engineering and economic viability and energy efficiency. A flow diagram is provided for each basic process. Four criteria are used to determine the most promising processes: raw material availability, type and amount of energy required, by-product demand/disposal and status of development. The most promising processes are determined to be the membrane process (with and without catalytic electrodes), Kel-Chlor, Mobay (direct electrolysis of hydrogen chloride), the Shell process (catalytic oxidation of hydrogen chloride) and oxidation of ammonium chloride. Each of these processes is further studied to determine what activities may be pursued.

  6. Chlorination of Carbon Nanotubes Obtained on the Different Metal Catalysts

    Directory of Open Access Journals (Sweden)

    Iwona Pełech

    2013-01-01

    Full Text Available In this paper, a chlorination method is proposed for simultaneous purification and functionalization of carbon nanotubes, thus increasing their ability to use. Carbon nanotubes were obtained by CVD method through ethylene decomposition on the nanocrystalline iron or cobalt or bimetallic iron-cobalt catalysts. The effects of temperature (50, 250, and 450°C in the case of carbon nanotubes obtained on the Fe-Co catalyst and type of catalyst (Fe, Co, Fe/Co on the effectiveness of the treatment and functionalization were tested. The phase composition of the samples was determined using the X-ray diffraction method. The quantitative analysis of metal impurity content was validated by means of the thermogravimetric analysis. Using X-ray Photoelectron Spectroscopy (XPS, Energy Dispersive Spectroscopy (EDS analysis, and also Mohr titration method, the presence of chlorine species on the surface of chlorinated samples was confirmed.

  7. Supplying sodium and chlorine is effective on patients with congestive heart failure

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Changcong Cui

    2005-01-01

    Objective: To analyze the relationship of severity of heart failure and the concentration of serum sodium(Na + ) and chlorine(Cl- ) and to explore the effect of supplying sodium and chlorine on patients with Congestive heart failure. Methods: 80 patients with congestive heart failure were divided into two groups, namely supplying and control group. Serum sodium and chlorine were measured in all these patients. All treatments but supplying sodium and chlorine were same between the supplying and control groups. Results:According to NYHA, patients who were in class Ⅳ had lower level of serum sodium and chlorine than those in class Ⅱ ( P < 0.05). The heart function was improved after the level of serum sodium and chlorine were raised. Conclusions: The concentration of serum sodium and chlorine relates to the severity of heart failure. The therapy of supplying sodium and chlorine is an effective way to decrease death rate.

  8. 76 FR 62149 - American Chemistry Council, The Chlorine Institute, Inc., the Fertilizer Institute, and PPG...

    Science.gov (United States)

    2011-10-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Surface Transportation Board American Chemistry Council, The Chlorine Institute, Inc., the Fertilizer... American Chemistry Council, The Chlorine Institute, Inc., The Fertilizer Institute (TFI), and...

  9. Toxicity of chlorine dioxide to early life stages of marine organisms

    Energy Technology Data Exchange (ETDEWEB)

    Hose, J.E.; Di Fiore, D.; Parker, H.S.; Sciarrotta, T.

    1989-03-01

    With increasing interest in minimizing exposure to chlorine, many electric generating and water treatment plants are exploring the use of alternative biocides such as chlorine dioxide. Unlike chlorine, chlorine dioxide does not react with ambient organic compounds to form potentially carcinogenic trihalomethanes such as chloroform. However, the toxicity of chlorine dioxide to aquatic organisms has received little study. No information exists on chlorine toxicity to marine organisms. Furthermore, West Coast electric power stations usually discharge chlorine intermittently once or twice daily and substantial mixing of receiving water occurs between treatments. Therefore, this study sought to obtain information on chlorine dioxide toxicity using an exposure schedule typical of generating stations which discharge into the marine environment. Early life history stages of a plant, invertebrate and fish were tested since these stages are generally acknowledged to be most sensitive to toxicants and are the stages that are most likely to be exposed to the effluent.

  10. Chlorine release from biomass. Part 6; Kloravgaang fraan biobraenslen. Del 6

    Energy Technology Data Exchange (ETDEWEB)

    Zintl, Frank; Stroemberg, Birgitta [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-04-01

    Chlorine release from model compounds and different biomass fuels has been studied during thermal treatment in an electric oven in inert atmosphere (N{sub 2}) and with addition of 10% O{sub 2}. The amount of chlorine in all investigated materials has been kept to 2% with addition of KCl solution in methanol. The amount of chlorine was analysed before and after treatment in the decided atmosphere and to the temperature chosen. The influence from different functional groups on the chlorine release at low temperatures has been studied in pyrolysis experiments of simple model compounds with different structures. A good correlation between the chlorine release and the functional groups in the model substances was achieved. Results from the experiments shows that the early chlorine release, is most likely to occur in all biofuels, since all biomass fuels contains biological material with significant amounts of functional groups which can interact with fuel chlorine ( inorganic chlorine)

  11. An unusual case of reversible acute kidney injury due to chlorine dioxide poisoning.

    Science.gov (United States)

    Bathina, Gangadhar; Yadla, Manjusha; Burri, Srikanth; Enganti, Rama; Prasad Ch, Rajendra; Deshpande, Pradeep; Ch, Ramesh; Prayaga, Aruna; Uppin, Megha

    2013-09-01

    Chlorine dioxide is a commonly used water disinfectant. Toxicity of chlorine dioxide and its metabolites is rare. In experimental studies, it was shown that acute and chronic toxicity were associated with insignificant hematological changes. Acute kidney injury due to chlorine dioxide was not reported. Two cases of renal toxicity due to its metabolites, chlorate and chlorite were reported. Herein, we report a case of chlorine dioxide poisoning presenting with acute kidney injury.

  12. Chlorine dioxide water disinfection: a prospective epidemiology study

    Energy Technology Data Exchange (ETDEWEB)

    Michael, G.E.; Miday, R.K.; Bercz, J.P.; Miller, R.G.; Greathouse, D.G.; Kraemer, D.F.; Lucas, J.B.

    1981-01-01

    An epidemiologic study of 198 persons exposed for 3 months to drinking water disinfected with chlorine dioxide was conducted in a rural village. A control population of 118 nonexposed persons was also studied. Pre-exposure hematologic and serum chemical parameters were compared with test results after 115 days of exposure. Chlorite ion levels in the water averaged approximately 5 ppM during the study period. Statistical analysis (ANOVA) of the data failed to identify any significant exposure-related effects. This study suggests that future evaluations of chlorine dioxide disinfection should be directed toward populations with potentially increased sensitivity to hemolytic agents.

  13. Kinetics and Mechanism of Bacterial Disinfection by Chlorine Dioxide1

    Science.gov (United States)

    Benarde, Melvin A.; Snow, W. Brewster; Olivieri, Vincent P.; Davidson, Burton

    1967-01-01

    Survival data are presented for a fecal strain of Escherichia coli exposed to three concentrations of chlorine dioxide at four temperatures. Chick's first-order reaction equation is generalized to a pseudo nth-order model. Nonlinear least squares curve-fitting of the survival data to the nth order model was performed on an analogue computer. The data were observed to follow fractional order kinetics with respect to survival concentration, with an apparent activation energy of 12,000 cal/mole. Initial experiments support the thesis that the mechanism of chlorine dioxide kill occurs via disruption of protein synthesis. Images Fig. 1 Fig. 2 Fig. 3 PMID:5339839

  14. Thermodynamic equilibrium diagram of the chlorine-titanium system

    Institute of Scientific and Technical Information of China (English)

    DU Ailing; GUO Xiaofei; ZHANG Heming; LIU Jiang

    2005-01-01

    The chemical and electrochemical equilibria of the chlorine-titanium system in the presence of gaseous phase were investigated. Many species, which consisted of chlorine and titanium, were considered. Various thermodynamic equilibria were calculated in the different pressures at different temperatures. The calculated results were shown as log p-1/T and E-T diagrams. These diagrams may be used as important tools for corrosion study and titanium production. The diagrams are also used to thermodynamically determine the existence areas of various species and so on.

  15. Sonochemical Treatment of Water Polluted by Chlorinated Organocompounds. A Review

    Directory of Open Access Journals (Sweden)

    Olivier Louisnard

    2010-02-01

    Full Text Available As one of several types of pollutants in water, chlorinated compounds have been routinely subjected to sonochemical analysis to check the environmental applications of this technology. In this review, an extensive study of the influence of the initial concentration, ultrasonic intensity and frequency on the kinetics, degradation efficiency and mechanism has been analyzed. The sonochemical degradation follows a radical mechanism which yields a very wide range of chlorinated compounds in very low concentrations. Special attention has been paid to the mass balance comparing the results from several analytical techniques. As a conclusion, sonochemical degradation alone is not an efficient treatment to reduce the organic pollutant level in waste water.

  16. Oxidation of pharmaceuticals by chlorine dioxide in biologically treated wastewater

    DEFF Research Database (Denmark)

    Hey, G.; Grabic, R.; Ledin, A.

    2012-01-01

    Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0–20mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended......O2, while in high COD effluent a significant increase in API oxidation was observed after treatment with 8mg/L ClO2. This study illustrates the successful degradation of several APIs during treatment of wastewater effluents with chlorine dioxide....

  17. Chlorine international thermodynamic tables of the fluid state

    CERN Document Server

    Angus, S; de Reuck, K M

    1985-01-01

    Chlorine: International Thermodynamic Tables of the Fluid State-8 is a four-chapter book that covers available and estimated data on chlorine; estimation of the element's properties; the correlating equations for the element; and how the tabulated properties are calculated from chosen equation. The tables in this book give the volume, entropy, enthalpy, isobaric heat capacity, compression factor, fugacity/pressure ratio, Joule-Thomson coefficient, ratio of the heat capacities, and speed of sound as a function of pressure and temperature. Given in the tables as well are the pressure, entropy, i

  18. Study of tolerance of enterobacteria to chlorine-based biocides in experimental models using chromogenic indicator tests

    Directory of Open Access Journals (Sweden)

    N.R. Efimochkina

    2015-09-01

    Full Text Available The species-specific composition of microbial contaminants of vegetable raw materials and equipment used in the production of biotechnological products and beverages fermentation are studied. 85 enterobacteria strains was isolated and investigated, 46 strains of the genera Enterobacter, Pantoea, Citrobacter, Serratia, Escherichia, Cronobacter was identified to the species level; the most frequently detected bacteria of the genera Enterobacter and Pantoea (about 50 %. For the first time developed and tested chromogenic in vitro model based that allows to quantify the degree of inhibition of gram-negative microflora under the influence of antimicrobial agents depending on the concentrations of biocides and density of bacterial populations. A comparative analysis of the tolerance of Enterobacteriaceae strains from different biotopes was conducted. Sensitivity to the treatment of chlorine-containing biocides in 26 strains of enterobacteria from plant material and 9 strains of Escherichia coli from the intestine of male rats of Wistar line was tested. Enterobacteria from vegetable raw materials and swabs were more resistant to antimicrobial action of chlorine, than the representatives of the populations of the normal intestinal microbiota. It is established that the active chlorine concentration of 50–100 mg/dm 3 , the most commonly used in the processing of vegetable raw materials, is not effective for Enterobacteriaceae, if the density of the microbial population is 10 5–7 cells/cm 3 and above. At an initial level of contamination with Enterobacteriaceae not more than 10 3 cells/cm 3 processing solutions with a concentration of active chlorine of 75 to 100 mg/dm 3 can provide effective disinfection of raw materials, equipment, or inventory. Experimental chromogenic in vitro model proposed to assess the impact of chlorine-based biocides on the degree of the enterobacteria inhibition, can be used to justify the selection and doses of

  19. Chlorine cell disinfection determination with flow cell cytometry and plate count (poster)

    NARCIS (Netherlands)

    Peters, M.C.F.M.; Keuten, M.G.A.; De Kreuk, M.K.; Van Loosdrecht, M.C.M.; Rietveld, L.C.

    2013-01-01

    Chlorine is used for disinfection in different water systems. This research focuses on chlorine disinfection in swimming pool water. In the Netherlands, free available chlorine concentrations in swimming pools are limited between 0.5-1.5 mg/L, which is based on a 4-log removal of Pseudomonas aerugin

  20. Estimates of Gibbs free energies of formation of chlorinated aliphatic compounds

    NARCIS (Netherlands)

    Dolfing, Jan; Janssen, Dick B.

    1994-01-01

    The Gibbs free energy of formation of chlorinated aliphatic compounds was estimated with Mavrovouniotis' group contribution method. The group contribution of chlorine was estimated from the scarce data available on chlorinated aliphatics in the literature, and found to vary somewhat according to the

  1. Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.

    Science.gov (United States)

    Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

    2012-08-28

    We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide.

  2. 21 CFR 177.2430 - Polyether resins, chlorinated.

    Science.gov (United States)

    2010-04-01

    ...) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only as... producing, manufacturing, packing, processing, preparing, treating, packaging, transporting, or holding food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyether resins, chlorinated. 177.2430 Section...

  3. Chlorinated Iridoid Glucosides from Veronica longifolia and their Antioxidant Activity

    DEFF Research Database (Denmark)

    Jensen, Søren Rosendal; Gotfredsen, Charlotte Held; Harput, U. Sebnem;

    2010-01-01

    From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol este...

  4. Riverine input of chlorinated hydrocarbons in the coastal pollution

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; Everaarts, J.M.

    of various chlorinated hydrocarbons. It deals with an in-depth analysis of pollution of the coastal ecosystem around the Netherlands, U.K. and Germany due to inputs of contaminants from the rivers namely, Elbe, Weser, Ems Ijssel, Rhine, Meuse, Scheldt, Thames...

  5. Physical property determinations of short chain chlorinated paraffins

    Energy Technology Data Exchange (ETDEWEB)

    Drouillard, K.G.D. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Soil Science; Hiebert, T.; Friesen, K.J. [Univ. of Winnipeg, Manitoba (Canada). Dept. of Chemistry; Muir, D.C.G. [Freshwater Inst., Winnipeg, Manitoba (Canada)

    1995-12-31

    Chlorinated paraffins (CP) are chlorinated derivatives of n-alkanes commonly utilized in commercial formulations of flame retardants, plasticizers and high pressure lubricants. Recent reviews on CPs have expressed concern regarding the potential toxicity and carcinogenic properties of these compounds. Of the various classes of CPs, short chain compounds (carbon chain lengths 10 to 13) appear to pose the greatest risk. There is little data available concerning key physical properties of CPs required to assess their environmental behavior and mobility. In this study, water solubilities, dissolved organic matter water partition coefficients (K{sub DOM}) and Henry`s Law constants were determined for short chain chlorinated paraffins by generator column, apparent solubility enhancement and gas-purging techniques. Water solubilities were determined for synthesized, isolated products of polychlorinated decanes, undecanes and dodecanes. Solubilities at 25 C were on the order of 2 to 140 {micro}g/L for tetra- to hexachlorodecane products. The Henry`s Law constants for tetra- and pentachlorodecane were determined to be 6.6 {+-} 0.6 and 3.5 {+-} 0.6 Pa{center_dot}m{sup 3}{center_dot}mol{sup {minus}1} respectively. Relationships between carbon chain length and degree of chlorination on the determined physical properties will be discussed.

  6. Chlorine stress mediates microbial surface attachment in drinking water systems.

    Science.gov (United States)

    Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

    2015-03-01

    Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

  7. Inactivation of human and simian rotaviruses by chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Shiaw (Brookhaven National Lab., Upton, NY (USA)); Vaughn, J.M. (Univ. of New England College of Medicine, Biddeford, ME (USA))

    1990-05-01

    The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4{degree}C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10{sup 5}-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate a neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.

  8. Inactivation of human and simian rotaviruses by chlorine dioxide.

    Science.gov (United States)

    Chen, Y S; Vaughn, J M

    1990-01-01

    The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4 degrees C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10(5)-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate at neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants. PMID:2160222

  9. Structural and optical properties of chlorinated plasma polymers

    Energy Technology Data Exchange (ETDEWEB)

    Turri, Rafael [Laboratorio de Plasmas Tecnologicos, Campus Experimental de Sorocaba, Universidade Estadual Paulista (UNESP), Avenida Tres de Marco 511, Alto de Boa Vista, 18087-180, Sorocaba, SP (Brazil); Davanzo, Celso U. [Instituto de Quimica, Universidade Estadual de Campinas, Campinas, SP (Brazil); Schreiner, Wido [Departamento de Fisica, Universidade Federal de Parana, PR (Brazil); Dias da Silva, Jose Humberto [Faculdade de Ciencias, Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil); Appolinario, Marcelo Borgatto [Laboratorio de Plasmas Tecnologicos, Campus Experimental de Sorocaba, Universidade Estadual Paulista (UNESP), Avenida Tres de Marco 511, Alto de Boa Vista, 18087-180, Sorocaba, SP (Brazil); Durrant, Steven F., E-mail: steve@sorocaba.unesp.br [Laboratorio de Plasmas Tecnologicos, Campus Experimental de Sorocaba, Universidade Estadual Paulista (UNESP), Avenida Tres de Marco 511, Alto de Boa Vista, 18087-180, Sorocaba, SP (Brazil)

    2011-12-30

    Amorphous hydrogenated chlorinated carbon (a-C:H:Cl) films were produced by the plasma polymerization of chloroform-acetylene-argon mixtures in a radiofrequency plasma enhanced chemical vapor deposition system. The main parameter of interest was the proportion of chloroform in the feed, R{sub C}, which was varied from 0 to 80%. Deposition rates of 80 nm min{sup -1} were typical for the chlorinated films. Infrared reflection-absorption spectroscopy revealed the presence of C-Cl groups in all the films produced with chloroform in the feed. X-ray photoelectron spectroscopy confirmed this finding, and revealed a saturation of the chlorine content at {approx} 47 at.% for R{sub C} {>=} 40%. The refractive index and optical gap, E{sub 04}, of the films were roughly in the 1.6 to 1.7, and the 2.8 to 3.7 eV range. These values were calculated from transmission ultraviolet-visible-near infrared spectra. Chlorination leads to an increase in the water surface contact angle from {approx} 40 Degree-Sign to {approx} 77 Degree-Sign .

  10. Biodegradation of chlorinated solvents in a water unsaturated topsoil

    DEFF Research Database (Denmark)

    Borch, T.; Ambus, P.; Laturnus, F.

    2003-01-01

    In order to investigate topsoils as potential sinks for chlorinated solvents from the atmosphere, the degradation of trichloromethane (CHCl3), 1,1,1-trichloroethane (CH3CCl3), tetrachloromethane (CCl4), trichloroethene (C2HCl3) and tetrachloroethene (C2Cl4) was studied in anoxic laboratory experi...

  11. Transformation of Chlorinated Hydrocarbons on Synthetic Green Rusts

    Science.gov (United States)

    Green rusts (GRs) are layered double hydroxides that contain both ferrous and ferric ions in their structure. GRs can potentially serve as a chemical reductant for degradation of chlorinated hydrocarbons. GRs are found in zerovalent iron based permeable reactive barriers and in c...

  12. Release of Chlorine and Sulfur during Biomass Torrefaction and Pyrolysis

    DEFF Research Database (Denmark)

    Saleh, Suriyati Binti; Flensborg, Julie Pauline; Shoulaifar, Tooran Khazraie

    2014-01-01

    -forming elements were torrefied/pyrolyzed in the temperature range of 150-500 degrees C. The relative release of chlorine and sulfur was calculated based on mass balance and analysis of the biomass before and after torrefaction. In selected cases, measurement of methyl chloride (CH3Cl) in the gas from straw...

  13. Transformation of chlorinated compounds by methanogenic granular sludge

    NARCIS (Netherlands)

    Eekert, van M.H.A.

    1999-01-01

    Chlorinated compounds are an important group of contaminants often found in sediments, groundwater, soils, wastewaters, and off-gasses. Many of these pollutants are found on the EPA list of Priority Pollutants indicating their potential hazard for the environment. Initial degradation can occur via d

  14. Degradation of Chlorinated Aromatic Compounds in UASB Reactors

    DEFF Research Database (Denmark)

    Christiansen, Nina; Hendriksen, Hanne Vang; Järvinen, Kimmo T.;

    1995-01-01

    Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded...

  15. ANALYSIS OF NASAL TISSUE FOR BIOMARKERS OF CHLORINE EXPOSURE

    Science.gov (United States)

    Both 3-chloro-tyrosine (CT) and 3,5-dichloro-tyrosine (dCT) are sensitive and specific biomarkers for evaluating exposure to chlorine gas (Cl2) and hypochlorous acid (HOCl). Previous investigations have focused on the formation of CT and dCT resulting from biochemical responses ...

  16. In situ aerobic cometabolism of chlorinated solvents: a review.

    Science.gov (United States)

    Frascari, Dario; Zanaroli, Giulio; Danko, Anthony S

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed.

  17. Electrochemical chlorine evolution at rutile oxide (110) surfaces

    DEFF Research Database (Denmark)

    Hansen, Heine Anton; Man, Isabela Costinela; Studt, Felix;

    2010-01-01

    of the oxygen binding energy, giving rise to a Sabatier volcano. By combining the surface phase diagram and the volcano describing the catalytic activity, we find that the reaction mechanism differs depending on catalyst material. The flexibility in reaction path means that the chlorine evolution activity...

  18. Disinfection byproduct yields from the chlorination of natural waters

    Science.gov (United States)

    Rathbun, R.E.

    1996-01-01

    Yields for the formation of trihalomethane and nonpurgeable total organic-halide disinfection byproducts were determined as a function of pH and initial free-chlorine concentration for the chlorination of water from the Mississippi, Missouri, and Ohio Rivers. Samples were collected at 12 sites on the Mississippi River from Minneapolis, MN, to New Orleans. LA, and on the Missouri and Ohio Rivers 1.6 km above their confluences with the Mississippi during the summer, fall, and spring seasons of the year. Yields varied little with distance along the Mississippi River, although the dissolved organic-carbon concentration decreased considerably with distance downstream. Yields for the Missouri and Ohio were comparable to yields for the Mississippi, despite much higher bromide concentrations for the Missouri and Ohio. Trihalomethane yields increased as the pH and initial free- chlorine concentration increased. Nonpurgeable total organic-halide yields also increased as the initial free-chlorine concentration increased, but decreased as the pH increased.

  19. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  20. The chlorine isotope fingerprint of the lunar magma ocean.

    Science.gov (United States)

    Boyce, Jeremy W; Treiman, Allan H; Guan, Yunbin; Ma, Chi; Eiler, John M; Gross, Juliane; Greenwood, James P; Stolper, Edward M

    2015-09-01

    The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free ("dry") Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because (37)Cl/(35)Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, (37)Cl/(35)Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high (37)Cl/(35)Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon's history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets.

  1. Chlorine-36 and the initial value problem

    Science.gov (United States)

    Davis, Stanley N.; Cecil, DeWayne; Zreda, Marek; Sharma, Pankaj

    Chlorine-36 is a radionuclide with a half-life of 3.01×105a. Most 36Cl in the hydrosphere originates from cosmic radiation interacting with atmospheric gases. Large amounts were also produced by testing thermonuclear devices during 1952-58. Because the monovalent anion, chloride, is the most common form of chlorine found in the hydrosphere and because it is extremely mobile in aqueous systems, analyses of both total Cl- as well as 36Cl have been important in numerous hydrologic studies. In almost all applications of 36Cl, a knowledge of the initial, or pre-anthropogenic, levels of 36Cl is useful, as well as essential in some cases. Standard approaches to the determination of initial values have been to: (a) calculate the theoretical cosmogenic production and fallout, which varies according to latitude; (b) measure 36Cl in present-day precipitation and assume that anthropogenic components can be neglected; (c) assume that shallow groundwater retains a record of the initial concentration; (d) extract 36Cl from vertical depth profiles in desert soils; (e) recover 36Cl from cores of glacial ice; and (f) calculate subsurface production of 36Cl for water that has been isolated from the atmosphere for more than one million years. The initial value from soil profiles and ice cores is taken as the value that occurs directly below the depth of the easily defined bomb peak. All six methods have serious weaknesses. Complicating factors include 36Cl concentrations not related to cosmogenic sources, changes in cosmogenic production with time, mixed sources of chloride in groundwater, melting and refreezing of water in glaciers, and seasonal groundwater recharge that does not contain average year-long concentrations of 36Cl. Résumé Le chlore-36 est un radionucléide de période 3.01×105a. Pour l'essentiel, le 36Cl dans l'hydrosphère provient des effets du rayonnement cosmique sur les gaz atmosphériques. De grandes quantités de 36Cl ont aussi été produites au cours des

  2. [Electrochemical reduction characteristics and mechanism of chlorinated hydrocarbon at the copper electrode].

    Science.gov (United States)

    Xu, Wen-Ying; Gao, Ting-Yao; Zhou, Rong-Feng; Ma, Lu-Ming

    2005-07-01

    The electrochemical reduction characteristics of chlorinated hydrocarbons were investigated by applying cyclic voltammetry technique. The reduction mechanism and reactivity of the chlorinated hydrocarbons at the copper electrodes were explored. The relation between the reductive reactivity at the copper electrode and the structures of this kind of compounds was discussed. The experimental results show that chlorinated paraffin hydrocarbons and a portion of chlorinated aromatic hydrocarbons could be reduced directly at the copper electrode; however, chlorinated aromatic hydrocarbons aren't easy to reduced directly at the copper electrode. The results provide a theoretical basis for the catalyzed iron inner electrolysis method.

  3. Selective synthesis and characterization of chlorins as sensitizers for photodynamic therapy

    Science.gov (United States)

    Montforts, Franz-Peter; Kusch, Dirk; Hoper, Frank; Braun, Stefan; Gerlach, Benjamin; Brauer, Hans-Dieter; Schermann, Guido; Moser, Joerg G.

    1996-04-01

    Chlorin type sensitizers have ideal photophysical properties for an application in PDT. The basic chlorin framework of these sensitizers has to be modified by attachment of lipophilic and hydrophilic residues to achieve a good cell uptake and tumor enrichment. In the present study we describe the selective synthesis of amphiphilic chlorins starting from the readily accessible red blood pigment heme. The photophysical properties of the well defined synthetic chlorins are characterized by photophysical investigations. The kinetic of cell uptake, the localization in the cell and the photodynamic behavior of the amphiphilic sensitizers are demonstrated by incubation of A 375 cancer cell lines with structurally different chlorins.

  4. Impact of January 2005 solar proton events on chlorine species

    Directory of Open Access Journals (Sweden)

    A. Damiani

    2012-01-01

    Full Text Available Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4. We used Aura Microwave Limb Sounder (MLS measurements to monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS on ENVISAT to retrieve ClONO2. SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes with the lowest values (of less than 0.25 ppbv on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases of more than 0.2 ppbv whereas both HOCl and ClO enhancements (about 0.1 ppbv have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv and ClONO2 enhancements (about 0.2 ppbv have been observed at higher latitudes (i.e., at nighttime roughly above 2 hPa.

    While WACCM4 reproduces most of the SPE-induced variability in the chlorine species fairly well, in some particular regions discrepancies between the modeled and measured temporal evolution of the abundances of chlorine species were found. HOCl changes are modelled very well with respect to both magnitude and geographic distribution. ClO decreases are reproduced at high latitudes, whereas ClO enhancements in the terminator region are underestimated and attributed to background variations. WACCM4 also reproduces the HCl depletion in the mesosphere but it does not show the observed decrease below about 2 hPa. Finally, WACCM4 simulations indicate that the observed ClONO2 increase is dominated by background variability, although SPE-induced production might contribute by 0.1 ppbv.

  5. The potential feasibility of chlorinic photosynthesis on exoplanets.

    Science.gov (United States)

    Haas, Johnson R

    2010-11-01

    The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

  6. Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions.

    Science.gov (United States)

    Kim, Tae-Kyoung; Moon, Bo-Ram; Kim, Taeyeon; Kim, Moon-Kyung; Zoh, Kyung-Duk

    2016-11-01

    We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.

  7. Simultaneous Control of Microorganisms and Disinfection By-products by Sequential Chlorination

    Institute of Scientific and Technical Information of China (English)

    CHAO CHEN; XIAO-JIAN ZHANG; WEN-JIE HE; HONG-DA HAN

    2007-01-01

    Objective To introduce a new sequential chlorination disinfection process in which short-term free chlorine and chloramine are sequentially added. Methods Pilot tests of this sequential chlorination were carried out in a drinking water plant. Results The sequential chlorination disinfection process had the same or better efficiency on microbe (including virus)inactivation compared with the free chlorine disinfection process. There seemed to be some synergetic disinfection effect between free chlorine and monochloramine because they attacked different targets. The sequential chlorination disinfection process resulted in 35.7%-77.0% TTHM formation and 36.6%-54.8% THAA5 formation less than the free chlorination process.The poorer the water quality was, the more advantage the sequential chlorination disinfection had over the free chlorination.Conclusion This process takes advantages of free chlorine's quick inactivation of microorganisms and chloramine's low disinfection by-product (DBP) yield and long-term residual effect, allowing simultaneous control of microbes and DBPs in an effective and economic way.

  8. The effect of photochemical dissociation on downwind chlorine dioxide plume concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Michalowicz, R.; Alp, E. [Bovar Environmental, Toronto, Ontario (Canada)

    1997-12-31

    The pulp and paper industry handles toxic gases which may present an inherent hazard to the safety of the general public in the surrounding area. One such toxic gas that may pose a hazard is chlorine dioxide. Spills of chlorine dioxide solution result in the gassing off of toxic clouds of chlorine dioxide. Under daytime dry conditions, chlorine dioxide decomposes photolytically to form chlorine and oxygen and intermediates, chlorine trioxide and chlorine hexoxide. Air dispersion modeling of chlorine dioxide releases which does not properly account for its photochemical decomposition will lead to overly conservative hazard zone estimates. Under these conditions, risk control measures and emergency response evacuation zones based on such estimates will be unnecessarily expensive, perhaps prohibitive. This paper investigates the photolytic rate of dissociation of chlorine dioxide under various atmospheric conditions. It was found that modeling based on the decomposition of chlorine dioxide gas, resulted in downwind distances to TLV-Short Term Exposure Limits which are considerably shorter than modeling based on chlorine dioxide dispersion with no decomposition.

  9. Formation of trichloromethane in chlorinated water and fresh-cut produce and as a result of reacting with citric acid

    Science.gov (United States)

    Chlorine (sodium hypochlorite) is commonly used by the fresh produce industry to sanitize wash water, fresh and fresh-cut fruits and vegetables. However, possible formation of harmful chlorine by-products is a concern. The objectives of this study were to compare chlorine and chlorine dioxide in t...

  10. Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometrie determination of chlorine dioxide in the presence of other chlorine species,viz,free chlorine,chlorite,chlorate and hypoehlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct speetrophotometrie determination for chlorine dioxide owing to the serious interference of free and combined chlorine.The procedure gave a linear calibration graph over the range 0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.

  11. Polychlorinated biphenyl toxicity to Japanese quail as related to degree of chlorination

    Science.gov (United States)

    Hill, E.F.; Heath, R.G.; Spann, J.W.; Williams, J.D.

    1974-01-01

    To learn if the percentage of chlorine in a mixture of polychlorinated biphenyls (PCB's) alone determines toxicity, Japanese quail were fed diets containing Aroelor 1248, 1254, or 1260 at levels that added equal amounts of chlorine to the feed. The experiment comprised two consecutive 5-day periods; three sublethal concentrations of chlorine were evaluated during the first period and three lethal concentrations during the second period. Evaluations utilized comparisons of mortality, time to death, weight change, and food consumption. Sublethal concentrations produced no detectable effects. Lethal concentrations with equal Chlorine showed Aroelor 1248 to be less toxic at the highest chlorine concentrations, but at lower concentrations Aroelor 1254 was more toxic than Aroclor 1260. Although chlorine percentage of a PCB is positively correlated with its avian toxicity, PCB toxicity is apparently not simply a function of chlorination.

  12. Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction state. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process. Compared to the Stretford Process, the Direct Chlorination Process requires about one-third the initial capital investment and about one-fourth the net daily expenditure.

  13. Fate of chlorinated fatty acids in migrating sockeye salmon and their transfer to arctic grayling

    DEFF Research Database (Denmark)

    Mu, Huiling; Ewald, G.; Nilsson, E.;

    2004-01-01

    organohalogen compounds in the salmon were halogenated fatty acids, predominantly chlorinated species that accounted for up to 35% of the extractable, organically bound chlorine (EOCl) in the fish tissues. The amount of chlorinated fatty acids in the salmon muscle decreased as a result of spawning migration....... The decrease was correlated with that of triacylglycerols in the salmon muscle, indicating the chlorinated fatty acids to be mobilized and metabolized to approximately the same extent as the other fatty acids. Chlorinated fatty acids were also transferred to the maturing roe in a manner similar...... to that of the unchlorinated fatty acids. Lipids of the Arctic grayling (Thymallus arcticus), a fish resident to the spawning lake of the salmon, contained higher concentrations of chlorinated fatty acids than grayling in a lake without migratory salmon. This may reflect a food-chain transfer of the chlorinated fatty acids...

  14. ASCORBIC ACID REDUCTION OF ACTIVE CHLORINE PRIOR TO DETERMINING AMES MUTAGENICITY OF CHLORINATED NATURAL ORGANIC MATTER (NOM)

    Science.gov (United States)

    Many potable water disinfection byproducts (DBPs) that result from the reaction of natural organic matter (NOM) with oxidizing chlorine are known or suspected to be carcinogenic and mutagenic. The Ames assay is routinely used to assess an overall level of mutagenicity for all com...

  15. Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation.

    Science.gov (United States)

    Zoeteman, B C; Hrubec, J; de Greef, E; Kool, H J

    1982-12-01

    A retrospective epidemiological study in The Netherlands showed a statistical association between chlorination by-products in drinking water and cancer of the esophagus and stomach for males. A pilot-plant study with alternative disinfectants was carried out with stored water of the Rivers Rhine and Meuse. It was demonstrated that the increase of direct acting mutagens after treatment with chlorine dioxide is similar to the effect of chlorination. Ozonation of Rhine water reduced the mutagenic activity for Salmonella typhimurium TA 98 both with and without metabolic activation. UV alone hardly affects the mutagenicity of the stored river water for S. typh. TA 98. In all studies, practically no mutagenic activity for S. typh. TA 100 was found. Although remarkable changes in the concentration of individual organic compounds are reported, the identity of the mutagens detected is yet unclear. Compounds of possible interest due to their removal by ozonation are 1,3,3-trimethyloxindole, dicyclopentadiene and several alkylquinolines. Compounds which might be responsible for the increased mutagenicity after chlorination are two brominated acetonitriles and tri(2-chlorethyl) phosphate. Furthermore, the concentration procedure with adsorption on XAD resin and the subsequent elution step may have affected the results. It is proposed to focus further research more on the less volatile by-products of disinfection than on the trihalomethanes.

  16. Formation of disinfection byproducts upon chlorine dioxide preoxidation followed by chlorination or chloramination of natural organic matter.

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Lee, Wontae

    2013-06-01

    Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation.

  17. Durability of Selected Membrane Materials when Exposed to Chlorine Gas

    Energy Technology Data Exchange (ETDEWEB)

    Eikeland, Marianne Soerflaten

    2001-03-01

    This thesis is focusing on the durability of selected membrane materials when exposed to chlorine gas in the temperature range 30-100{sup o}C. Studies of the changes of membrane separation properties and the mechanisms promoting these changes have been studied. The selected membrane materials were poly(dimethylsioxane) (PDMS), Fluorel, fluorosilicone, and blends of PDMS and Fluorel. The thesis is organised in seven chapters. The first chapter gives an introduction to the background of the work. The second chapter presents the theory for gas separation using dense rubbery membranes. The properties of the selected membrane materials are presented in chapter three. The fourth chapter describes degradation mechanisms for polymeric materials in general and for the selected membrane materials in particular. Presentation of the experimental work is given in chapter five, while the results with discussions are presented in chapter six. The conclusions and recommendations for further studies are given in chapter seven. Five appendixes are attached: Appendix A describes the calculations of permeability and solubility coefficients and the accuracy of the experimental measurements. Appendix B summarises the measured values in tables and Appendix C describes the analytical methods. Appendix D gives the properties of the gases used in the experiments. Appendix E is the article ''Durability of Poly(dimethylsiloxane) when Exposed to Chlorine Gas'', submitted to the Journal of Applied Polymer Science. Highly crosslinked PDMS was found to have an initial high permeability for chlorine gas and a high Cl{sub 2}/O{sub 2} selectivity. However when exposed to chlorine gas the permeability decreased significantly. Crosslinking of the PDMS polymer chain and chlorination of the polymer gave a denser polymer structure and thus lower permeability. Fluorel showed very low permeabilities and selectivities for the gases in question and was thus not interesting for this

  18. Chlorine isotope behavior during prograde metamorphism of sedimentary rocks

    Science.gov (United States)

    Selverstone, Jane; Sharp, Zachary D.

    2015-05-01

    Chlorine stable isotope compositions of two sedimentary sequences and their metamorphic equivalents were measured in order to study fractionation effects during prograde metamorphism and devolatilization. Protoliths (n = 25) were collected from a 50 m section of Triassic fluvial and playa-lake strata and Jurassic (Liassic) marine black shales in a well-characterized quarry. Low greenschist to middle amphibolite facies equivalents (n > 80) were collected from the Glarus Alps, Urseren Zone, and Lucomagno region. Bulk δ37Cl values are constant within individual sedimentary layers, but vary from -2.0 to + 2.4 ‰ in Triassic rocks and from -3.0 to 0‰ in the black shales. Dolomitic and gypsiferous samples have positive δ37Cl values, but marls and shales are isotopically negative. Bulk Cl contents show only small declines during the earliest stages of metamorphism. Metamorphic equivalents of the Triassic and Liassic protoliths record the same overall ranges in δ37Cl as their protoliths. Samples with highly correlated bulk compositions but different metamorphic grade show no statistically significant difference in δ37Cl. These data lead to the following conclusions: (1) Terrestrial and marine sedimentary rocks display large primary heterogeneities in chlorine isotope composition. As a result, an unambiguous "sedimentary signature" does not exist in the chlorine stable isotope system. (2) No isotopic fractionation is discernable during metamorphic devolatilization, even at low temperatures. Alpine-style metamorphism thus has little to no effect on bulk chlorine isotopic compositions, despite significant devolatilization. (3) Cl is largely retained in the rocks during devolatilization, contrary to the normally assumed hydrophilic behavior of chlorine. Continuous release of mixed-volatile C-O-H fluids likely affected Cl partitioning between fluid and minerals and allowed chlorine to remain in the rocks. (4) There is no evidence for fluid communication across (meta

  19. Differences in the action of lower and higher chlorinated polychlorinated naphthalene (PCN) congeners on estrogen dependent breast cancer cell line viability and apoptosis, and its correlation with Ahr and CYP1A1 expression.

    Science.gov (United States)

    Gregoraszczuk, Ewa L; Barć, Justyna; Falandysz, Jerzy

    2016-07-29

    There are data showing that exposition to PCNs mixture increased incidence of gastrointestinal and respiratory neoplasms, but data regarding incidence of hormone-dependent cancer so far not shown. The objective was to determine if exposure to single lower and higher chlorinated PCN congeners is associated with altered proliferation and apoptosis of estrogen dependent breast cancer cells, and whether such effects are related to induction of AhR and CYP1A1 protein expression. MCF-7 cells were exposed to PCN 34, 39, 42, 46, 48, 52, 53, 54, 66, 67, 70, 71, 73 and 74 at concentrations of 100-10,000pg/ml. We evaluated the action of these PCN congeners on cell proliferation, DNA fragmentation and caspase-8,-9 activity. AhR and CYP1A1 protein expression and CYP1A1 activity was evaluated at a concentration of 1000pg/ml. An opposite action of tri- to tetraCNs than of penta-to heptaCNs on cell proliferation and apoptosis was evident. Tetra PCNs increased cell proliferation, but had no effect on DNA fragmentation nor caspase activity. Fast induction of CYP1A1 protein expression under the influence of lower chlorinated PCNs suggests faster metabolism and a possible stimulatory action of locally formed metabolites on cell proliferation. None of the higher chlorinated PCNs affected cell proliferation but all higher chlorinated PCNs increased caspase-8 activity, and hexa PCNs also increased caspase-9 activity. The rapid activation of the Ah receptor and CYP1A1 protein expression by higher chlorinated PCNs point to their toxicity; however, it is not sufficient for potential carcinogenicity. Action of lower chlorinated naphthalenes metabolites should be explored.

  20. Mechanism of chlorinating lanthanum oxide and cerium oxide with ammonium chloride

    Institute of Scientific and Technical Information of China (English)

    朱国才; 李赋屏; 肖明贵

    2003-01-01

    Using ammonium chloride(NH4Cl)as a chlorinating agent,the effects of chlorinating temperature,at 300℃ for 90 min,and have no advantage to chlorination of lanthanum and cerium oxides at higher temperature.The thermal decomposition of LaCl3 and CeCl3 is carried out to explore the mechanism of chlorinating lanthanum and cerium oxides.At the same time,the chlorination of lanthanum and cerium oxides is not devoted to the HCl decomposed from NH4Cl,but to NH4Cl directly taking part in the chlorination of La2O3 and CeO2.The lanthanum and cerium oxides in chlorination firstly form intermediate LaOCl and CeOCl,and then transfer to LaCl3 and CeCl3,fither prove the existence of the intermediates LaOCl and CeOCl.Therefore the chlorinating temperature and time should strictly be controlled when the lanthanum oxide and cerium oxide are chlorinated with NH4 Cl.And over-dosage of NH4 Cl should be also applied in the process of chlorination.

  1. First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

    Directory of Open Access Journals (Sweden)

    V. Zitko

    2001-01-01

    Full Text Available Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

  2. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process.

    Science.gov (United States)

    Wang, Ding; Bolton, James R; Andrews, Susan A; Hofmann, Ron

    2015-06-15

    Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an advanced oxidation process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).

  3. Effects of combined UV and chlorine treatment on chloroform formation from triclosan.

    Science.gov (United States)

    Ben, Weiwei; Sun, Peizhe; Huang, Ching-Hua

    2016-05-01

    The co-exposure to UV irradiation and free chlorine may occur in certain drinking water and wastewater treatment systems. This study investigated the effects of simultaneous low pressure ultraviolet (LPUV) irradiation and free chlorination on the formation of chloroform from triclosan which is a commonly used antibacterial agent. Different treatment systems (i.e., combined UV/chlorine, UV alone, and chlorine alone) were applied to examine the degradation of triclosan and formation of chloroform. The fate of representative intermediates, including chlorinated triclosan, dechlorinated triclosan intermediates and 2,4-dichlorophenol, were tracked to deduce the effect of combined UV/chlorine on the transformation of chloroform formation precursors. The relation between intermediates degradation and chloroform formation was investigated in depth by conducting stepwise experiments with UV and chlorine in different sequences. Results indicate that the combined UV/chlorine notably enhanced the chloroform formation from triclosan. From the reaction mechanism perspective the combined UV/chlorine, where the direct photolysis may play an important role, could accelerate the decay of intermediates and facilitate the generation of productive chloroform precursors. The radicals had modest influence on the degradation of triclosan and intermediates and partly hindered the formation of chloroform. These results emphasize the necessity of considering disinfection by-products formation in the application of combined UV/chlorine technology during water treatment.

  4. Detection, identification and formation of new iodinated disinfection byproducts in chlorinated saline wastewater effluents.

    Science.gov (United States)

    Gong, Tingting; Zhang, Xiangru

    2015-01-01

    The use of seawater for toilet flushing introduces high levels of inorganic ions, including iodide ions, into a city's wastewater treatment systems, resulting in saline wastewater effluents. Chlorination is widely used in disinfecting wastewater effluents owing to its low cost and high efficiency. During chlorination of saline wastewater effluents, iodide may be oxidized to hypoiodous acid, which may further react with effluent organic matter to form iodinated disinfection byproducts (DBPs). Iodinated DBPs show significantly higher toxicity than their brominated and chlorinated analogues and thus have been drawing increasing concerns. In this study, polar iodinated DBPs were detected in chlorinated saline wastewater effluents using a novel precursor ion scan method. The major polar iodinated DBPs were identified and quantified, and their organic precursors and formation pathways were investigated. The formation of iodinated DBPs under different chlorine doses and contact times was also studied. The results indicated that a few polar iodinated DBPs were generated in the chlorinated saline primary effluent, but few were generated in the chlorinated saline secondary effluent. Several major polar iodinated DBPs in the chlorinated saline primary effluent were proposed with structures, among which a new group of polar iodinated DBPs, iodo-trihydroxybenzenesulfonic acids, were identified and quantified. The organic precursors of this new group of DBPs were found to be 4-hydroxybenzenesulfonic acid and 1,2,3-trihydroxybenzene, and the formation pathways of these new DBPs were tentatively proposed. Both chlorine dose and contact time affected the formation of iodinated DBPs in the chlorinated saline wastewater effluents.

  5. CHEMICAL ANALYSIS OF REVERSE OSMOSIS MEMBRANE AND XAD RESIN ADSORPTION CONCENTRATES OF WATER DISINFECTED BY CHLORINATION OR OZONATION/CHLORINATION PROCESSES

    Science.gov (United States)

    Chemical Analysis of Reverse Osmosis Membrane and XAD Resin Adsorption Concentrates of Water Disinfected by Chlorination or Ozonation/Chlorination Processes.J. E. Simmons1, S.D. Richardson2, K.M. Schenck3, T. F. Speth3, R. J. Miltner3 and A. D. Thruston21 NHEE...

  6. Chlorine Nuclear Quadrupole Hyperfine Structure in the Vinyl - Chloride Complex

    Science.gov (United States)

    Leung, Helen O.; Marshall, Mark D.; Messinger, Joseph P.

    2015-06-01

    The microwave spectrum of the vinyl chloride--hydrogen chloride complex, presented at last year's symposium, is greatly complicated by the presence of two chlorine nuclei as well as an observed, but not fully explained tunneling motion. Indeed, although it was possible at that time to demonstrate conclusively that the complex is nonplanar, the chlorine nuclear quadrupole hyperfine splitting in the rotational spectrum resisted analysis. With higher resolution, Balle-Flygare Fourier transform microwave spectra, the hyperfine structure has been more fully resolved, but appears to be perturbed for some rotational transitions. It appears that knowledge of the quadrupole coupling constants will provide essential information regarding the structure of the complex, specifically the location of the hydrogen atom in HCl. Our progress towards obtaining values for these constants will be presented.

  7. Challenges in subsurface in situ remediation of chlorinated solvents

    DEFF Research Database (Denmark)

    Broholm, Mette Martina; Fjordbøge, Annika Sidelmann; Christiansen, Camilla Maymann

    2014-01-01

    Chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality at many sites worldwide. In situ remediation of these sites is particularly challenging in heterogeneous fractured media and where the solvents are present as DNAPL. In situ remediation by chemical...... as well as biological degradation of chlorinated solvents is a contact sport and requires direct contact between the contaminant and the reactants and/or degrading microorganisms. In fractured geologic media, where contaminants have spread to the low permeability matrix by diffusion, the contact between......-clay mixing for contact; hydrophobic and/or mobile nano-reactants targeting DNAPL. The complexity of the technologies varies greatly and the current level of implementation ranges from multiple full scale applications to bench scale testing. However, the basic degradation reaction involved is usually well...

  8. Chemisorption of chlorine and sulfur dioxide on zinc oxide

    Energy Technology Data Exchange (ETDEWEB)

    Vinokurov, A.A.; Derlyukova, L.E.; Evdokimov, V.I.

    1987-03-10

    The chemisorption of sulfur dioxide and chlorine on the surface of zinc oxide and the change in the electric conductivity of ZnO during the chemisorption process were studied. It was shown that both gases induce a negative charging of the surface of zinc oxide. The kinetics of the chemisorption of Cl/sub 2/ and SO/sub 2/ is described by the Zel'dovich-Roginskii equation. The mutual influence of sulfur dioxide and chlorine during successive chemisorption was investigated. It was shown that the nature of the mutual influence depends on the temperature and the sequence of action of the gases. The results obtained were analyzed from the standpoint of the electronic theory of chemisorption on semiconductors.

  9. Pressured liquid chlorine leakage accident simulation in highway tunnel

    Directory of Open Access Journals (Sweden)

    LI Jianfeng, LIU Mao, WANG Wei

    2010-03-01

    Full Text Available With the national economic development, China's transportation infrastructure has also made great progress, particularly in the highway. How to reduce the accident consequence that occurred in the highway tunnel has been the tropical topic in China. The liquid Chlorine accidental leakage in highway tunnel was exemplified for the poisonous gas dispersion consequence analysis using computational fluid dynamics. First, the GAMBIT code was used to create geometrical models and generate meshes. Second, by using the FLUENT code, the Chlorine gas dispersion in the highway tunnel was simulated and the scenarios with different leak sources were discussed. Case study shows that the FLUENT code was useful on the simulation of gas dispersion in highway tunnel that serves the prerequisite for the further research.

  10. MECHANISM OF CHLORATE FORMATION IN CHLORINE DIOIXDE DELIGNIFICATION

    Institute of Scientific and Technical Information of China (English)

    Byung-HoYoon; Li-JunWangI; Se-JongKim

    2004-01-01

    The effect of pH on chlorate formation duringchlorine dioxide delignification of oxygen delignifiedkraft pulp was studied. Chlorate formation was foundto increase slightly when pH was increased from 1.8to 2.5, further increase of pH decreased chlorateformation.The above phenomenon is explained by thecombination of two mechanisms, one by the reactionbetween hypochlorous acid and chlorite, another bythe effect of chlorine on the regeneration of chlorinedioxide. The first mechanism suggests that chlorateformation is highly dependent on HC10concentration which decreases with increasing pHand causes chlorate formation to behave in the sametrend. The second mechanism suggests that chlorinefavors the regeneration of chlorine dioxide whileHCIO favors chlorate formation, thus lowering thepH from about 4 to the acidic end should decreaseschlorate formation. Thethe maximum formation2.5.two opposite effects lead toof chlorate at around pH

  11. Chlorine trifluoride (1963); Le trifluorure de chlore (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, L.M.; Gillardeau, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    This monograph on chlorine trifluoride may be considered as a working tool useful in gaseous diffusion research. It consists of data gathered from the literature and includes furthermore a certain amount of original data. This monograph groups together the physical, chemical and physiological properties of chlorine trifluoride, as well as the preparation and analytical methods. It has been thought wise to add some technological information, and the safety regulations governing its use. (authors) [French] Cette monographie sur le trifluorure de chlore doit etre consideree comme un instrument de travail dans le cadre des recherches sur la diffusion gazeuse. Il etait necessaire de grouper les donnees eparses dans la litterature. Elle comprend en outre un certain nombre de donnees originales. Cette monographie groupe les proprietes physiques, chimiques et physiologiques du trifluorure de chlore, ainsi que ses methodes de preparation et d'analyse. On a juge utile de joindre des indications technologiques et les consignes de securite concernant son emploi. (auteurs)

  12. Chlorinated alkaloids in Menispermum dauricum DC: root culture.

    Science.gov (United States)

    Sugimoto, Y; Babiker, H A; Saisho, T; Furumoto, T; Inanaga, S; Kato, M

    2001-05-18

    Feeding experiments using (36)Cl showed that Menispermum dauricum root culture produces four alkaloids containing chlorine. They included the novel alkaloids dauricumine and dauricumidine as well as the known alkaloids acutumine and acutumidine. The structures of novel alkaloids were established by spectroscopic, crystallographic, and chemical methods. These four alkaloids were labeled with (36)Cl, isolated, and fed independently to root cultures. Mutual conversion between acutumine and acutumidine, and between dauricumine and dauricumidine by N-methylation and N-demethylation, was demonstrated. Moreover, dauricumine was converted to acutumine and acutumidine. Epimerization of acutumidine to dauricumidine or vice versa was not observed. These results suggest that dauricumine is the first chlorinated alkaloid formed in cultured M. dauricum roots. Skewed distribution of radioactivity derived from labeled dauricumine is proof that epimerization at C-1 proceeds at a lower rate than N-demethylation.

  13. Phytoscreening of BTEX and chlorinated solvents by tree coring

    DEFF Research Database (Denmark)

    Nielsen, Mette Algreen; Broholm, Mette Martina; Trapp, Stefan

    Background/Objectives. Site characterization is often time consuming and a financial burden for the site owners, which raises a demand for rapid and inexpensive screening methods. Tree coring is a phytoscreening method useful for detection of contamination with organic compounds. The method takes......(s). The measured concentrations are also compared to concentrations detected in soil and/or groundwater. Furthermore, the two screening technologies Tree coring and Soil air sampling have been compared to evaluate the feasibility of the tree coring method. Results/Lessons Learned. The method of tree coring can...... detect contamination with BTEX and chlorinated solvents in the shallow subsurface. The uptake of BTEX into trees varies to a greater extent with the site conditions and tree species than chlorinated solvents, which lead to greater uncertainty. Tree coring is semi-quantitative, low...

  14. Antibacterial effect of chlorine dioxide and hyaluronate on dental biofilm

    OpenAIRE

    Al-bayaty, F.; Taiyeb-ali, T.; Abdulla, M. A.; Hashim, F.

    2010-01-01

    The objective of this study is to investigate antimicrobial action of chlorine dioxide (ClO(2)) gel and hyaluronate gel (Gengigel (R)) on dental biofilm. Pooled supra and subgingival dental biofilm were obtained from healthy individuals and incubated aerobically and anaerobically. Plaque bacteria investigated including Streptococcus constellatus, Streptococcus mitis, Eikenella corrodens, Fusobacterium nucleatum, dental plaque pool samples (aerobic and anaerobic) and Staphylococcus aureus and ...

  15. Evaluation of low-chlorine TATB from a production source

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, T.L.; Osborn, A.G.; Johnson, H.D.; Duncan, A.A.; Schaffer, C.L.

    1981-08-01

    Six production lots of low-chlorine TATB powder have been evaluated. Five of the lots were made by a wet-amination process and the other was made by an emulsion-amination process. LX-17 physical properties specimens made from the five wet-aminated TATB lots were exceptionally strong and comparable to dry-aminated TATB, while the emulsion-aminated lot of TATB had lower strength.

  16. SEPARATION OF NEPTUNIUM FROM PLUTONIUM BY CHLORINATION AND SUBLIMATION

    Science.gov (United States)

    Fried, S.M.

    1958-11-18

    A process is described for separating neptunium from plutonium. The method consists in chlorinating a mixture of the oxides of Np and Pu by contacting the mixture with carbon tetrachloride at about 500 icient laborato C. ln this manner the Np is converted to the tetrachlorlde and the Pu converted to the trichloride. Since NpCl/sub 4/ is more latile than PuCl/sub 3/, the separation ls effected by vaporing sad subsequently condenslng the NpCl/sub 4/.

  17. Biological instability in a chlorinated drinking water distribution network.

    Science.gov (United States)

    Nescerecka, Alina; Rubulis, Janis; Vital, Marius; Juhna, Talis; Hammes, Frederik

    2014-01-01

    The purpose of a drinking water distribution system is to deliver drinking water to the consumer, preferably with the same quality as when it left the treatment plant. In this context, the maintenance of good microbiological quality is often referred to as biological stability, and the addition of sufficient chlorine residuals is regarded as one way to achieve this. The full-scale drinking water distribution system of Riga (Latvia) was investigated with respect to biological stability in chlorinated drinking water. Flow cytometric (FCM) intact cell concentrations, intracellular adenosine tri-phosphate (ATP), heterotrophic plate counts and residual chlorine measurements were performed to evaluate the drinking water quality and stability at 49 sampling points throughout the distribution network. Cell viability methods were compared and the importance of extracellular ATP measurements was examined as well. FCM intact cell concentrations varied from 5×10(3) cells mL(-1) to 4.66×10(5) cells mL(-1) in the network. While this parameter did not exceed 2.1×10(4) cells mL(-1) in the effluent from any water treatment plant, 50% of all the network samples contained more than 1.06×10(5) cells mL(-1). This indisputably demonstrates biological instability in this particular drinking water distribution system, which was ascribed to a loss of disinfectant residuals and concomitant bacterial growth. The study highlights the potential of using cultivation-independent methods for the assessment of chlorinated water samples. In addition, it underlines the complexity of full-scale drinking water distribution systems, and the resulting challenges to establish the causes of biological instability.

  18. Biological instability in a chlorinated drinking water distribution network.

    Directory of Open Access Journals (Sweden)

    Alina Nescerecka

    Full Text Available The purpose of a drinking water distribution system is to deliver drinking water to the consumer, preferably with the same quality as when it left the treatment plant. In this context, the maintenance of good microbiological quality is often referred to as biological stability, and the addition of sufficient chlorine residuals is regarded as one way to achieve this. The full-scale drinking water distribution system of Riga (Latvia was investigated with respect to biological stability in chlorinated drinking water. Flow cytometric (FCM intact cell concentrations, intracellular adenosine tri-phosphate (ATP, heterotrophic plate counts and residual chlorine measurements were performed to evaluate the drinking water quality and stability at 49 sampling points throughout the distribution network. Cell viability methods were compared and the importance of extracellular ATP measurements was examined as well. FCM intact cell concentrations varied from 5×10(3 cells mL(-1 to 4.66×10(5 cells mL(-1 in the network. While this parameter did not exceed 2.1×10(4 cells mL(-1 in the effluent from any water treatment plant, 50% of all the network samples contained more than 1.06×10(5 cells mL(-1. This indisputably demonstrates biological instability in this particular drinking water distribution system, which was ascribed to a loss of disinfectant residuals and concomitant bacterial growth. The study highlights the potential of using cultivation-independent methods for the assessment of chlorinated water samples. In addition, it underlines the complexity of full-scale drinking water distribution systems, and the resulting challenges to establish the causes of biological instability.

  19. Chlorine dioxide against bacteria and yeasts from the alcoholic fermentation

    Science.gov (United States)

    Meneghin, Silvana Perissatto; Reis, Fabricia Cristina; de Almeida, Paulo Garcia; Ceccato-Antonini, Sandra Regina

    2008-01-01

    The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration (MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis (10 ppm) and Leuconostoc mesenteroides (50 ppm) than for Lactobacillus fermentum (75 ppm) and Lactobacillus plantarum (125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran® (recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran® dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies (dispersed cells) seemed to be more sensitive than wrinkled yeast colonies (clustered cells/pseudohyphal growth), both isolated from an alcohol-producing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms. PMID:24031227

  20. Natural chlorine and fluorine in the atmosphere, water and precipitation

    Science.gov (United States)

    Friend, James P.

    1990-01-01

    The geochemical cycles of chlorine and fluorine are surveyed and summarized as framework for the understanding of the global natural abundances of these species in the atmosphere, water, and precipitation. In the cycles the fluxes into and out of the atmosphere can be balanced within the limits of our knowledge of the natural sources and sinks. Sea salt from the ocean surfaces represent the predominant portion of the source of chlorine. It is also an important source of atmospheric fluorine, but volcanoes are likely to be more important fluorine sources. Dry deposition of sea salt returns about 85 percent of the salt released there. Precipitation removes the remainder. Most of the sea salt materials are considered to be cyclic, moving through sea spray over the oceans and either directly back to the oceans or deposited dry and in precipitation on land, whence it runs off into rivers and streams and returns to the oceans. Most of the natural chlorine in the atmosphere is in the form of particulate chloride ion with lesser amounts as gaseous inorganic chloride and methyl chloride vapor. Fluorine is emitted from volcanoes primarily as HF. It is possible that HF may be released directly form the ocean surface but this has not been confirmed by observation. HCl and most likely HF gases are released into the atmosphere by sea salt aerosols. The mechanism for the release is likely to be the provision of protons from the so-called excess sulfate and HNO3. Sea salt aerosol contains fluorine as F(-), MgF(+), CaF(+), and NaF. The concentrations of the various species of chlorine and fluorine that characterize primarily natural, unpolluted atmospheres are summarized in tables and are discussed in relation to their fluxes through the geochemical cycle.

  1. The pool chlorine hypothesis and asthma among boys.

    LENUS (Irish Health Repository)

    Cotter, A

    2012-01-31

    Swimming pool sanitation has largely been concerned with the microbiological quality of pool water, which is normally treated using a number of chlorine products. Recent studies have pointed to the potential hazards of chlorine by-products to the respiratory epithelium, particularly in indoor, poorly ventilated, pools. The aim of our study was to elucidate whether chronic exposure to indoor chlorinated swimming pools was associated with an increased likelihood of the development of asthma in boys. METHODS: The subjects were boys aged between 6 and 12 years. Data was collected by means of parental responses to a standardized asthma questionnaire (ISAAC: International Study of Asthma and Allergies in Childhood), supplemented with additional questions regarding frequency of attendance, number of years attendance, whether the child is a swimming team member. The questionnaire return rate was 71\\/% (n = 121). 23 boys were excluded on the basis that they had asthma before they started swimming (n = 97). There was a significant association between number of years a boy had been swimming and the likelihood of wheezing in the last 12 months (p = 0.009; OR = 1.351; 95% CI = 1.077-1.693) and diagnosed asthma (p = 0.046; OR = 1.299; 95% CI = 1.004-1.506). The greater the number the number of years a boy had been attending an indoor, chlorinated pool, the greater the likelihood of wheezing in the last 12 months or "had asthma". Age, parental smoking habits and being a swimming team member had no association with any of the asthma variables examined. Swimming pool attendance may be a risk factor in asthma in boys.

  2. The influence of chlorine on the gasification of wood

    Energy Technology Data Exchange (ETDEWEB)

    Scala, C. von; Struis, R.; Stucki, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Chlorides of the heavy metals copper, lead and zinc inhibit the CO{sub 2}-gasification reaction of charcoal. This is observed either by impregnation the wood with the salts before pyrolysis or by mechanically mixing the salts with the charcoal before gasification. Charcoal impregnated or mixed with ammonium chloride reacts more slowly than untreated charcoal. Treating the charcoal with HCl also influences negatively the gasification reactivity, indicating that chlorine plays an important role in the gasification. (author) 2 figs., 4 refs.

  3. Mass transfer properties of chlorinated aromatic polyamide reverse osmosis membranes

    OpenAIRE

    Ettori, Axel; Gaudichet-Maurin, Emmanuelle; Aimar, Pierre; Causserand, Christel

    2012-01-01

    International audience; Water (A) and solute (B) permeability of aromatic polyamide (PA) reverse osmosis membranes (RO) were monitored under varying applied pressure, solute nature and concentration to assess their evolution after exposure of the membrane to free chlorine. Above a threshold value of 400 ppm h HOCl water permeability was influenced by permeation conditions during both filtration of ultrapure water (UP water) and reverse osmosis of salts performed sequentially. Water permeabili...

  4. Chlorine Analysis by Diode Laser Atomic Absorption Spectrometry

    Institute of Scientific and Technical Information of China (English)

    Joachim Koch; Aleksandr Zybin; Kay Niemax

    2000-01-01

    The general characteristics of Diode Laser Absorption Spectrometry (DLAAS) in low pressure plasmas particulary with respect to the detection of non-metals are comprehensively recapitulated and discussed. Furthermore, a detector, which is based on DLAAS in a microwave-induced low pressure plasma as an alternative technique for halogene-specific analysis of volatile compounds and polymeric matrices is described. The analytical capability of the technique is demonstrated on the chlorine-specific analysis of ablated polymer fragments as well as gas chromatographically separated hydrocarbons. Since the measurements were carried out by means of a balanced-heterodyne detection scheme, different technical noise contributions, such as laser excess and RAM noise could efficiently be suppressed and the registered absorption was limited only by the principal shot noise. Thus, in the case of the polymer analysis a chlorine-specific absolute detection limit of 10 pg could be achieved. Furthermore, fundamental investigations concerning the influence of hydrocarbons on the dissociation capability of the microwave induced plasma were performed. For this purpose, the carbon-, chlorine-and hydrogen-specific stoichiometry of the compounds were empirically determined. Deviations from the exspected proportions were found to be insignificant, implying the possibility of internal standardization relative to the response of a reference sample.

  5. Behavior and control of chlorine in dyestuff residue incineration

    Institute of Scientific and Technical Information of China (English)

    YAN Jian-hua; TAN Zhong-xin; JIANG Xue-guang; CHI Yong; CEN Ke-fa

    2006-01-01

    Dyestuff residue, a type of hazardous waste, is incinerated in the tubular furnace, and thermodynamic equilibrium model is used to calculate and analyze the chlorine behavior. The HCl emission and its effects on the behaviors of heavy metals are studied.Meanwhile, the effects of three dechlorine reagents are predicted at a high temperature. Results show that HCl emission is dependent on incineration temperature. The HCl evaporated mainly derives from the organic chlorine. Under the working condition of 500--900℃, the main products of Hg, Pb, Cu, Ni, Zn, and Mn in reaction with HCl are HgCl2 (g), PbCl4(g), PbCl2 (g), (CuCl)3 (g), NiCl2 (s),NiCl2 (g), ZnCl2 (s), ZnCl2 (g), Zn (g), MnCl2 (s), and MnCl2 (g), respectively. Among the three dechlorine reagents, CaCO3 is optimal to remove chlorine at high temperature, little of HCl is released below 800℃, whereas Fe3O4 is unstable at high temperature.

  6. Depletion of chlorine into HCl ice in a protostellar core

    CERN Document Server

    Kama, M; Lopez-Sepulcre, A; Wakelam, V; Dominik, C; Ceccarelli, C; Lanza, M; Lique, F; Ochsendorf, B B; Lis, D C; Caballero, R N; Tielens, A G G M

    2014-01-01

    The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances $<10^{-5}$ has not yet been well studied. Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H$_{2}$ hyperfine collisional excitation rate coefficients. A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9e-11, a factor of only 0.001 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous fo...

  7. Analysis of short-chain chlorinated paraffins: a discussion paper.

    Science.gov (United States)

    Pellizzato, Francesca; Ricci, Marina; Held, Andrea; Emons, Hendrik

    2007-09-01

    Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.

  8. Enhanced disinfection efficiency of mechanically mixed oxidants with free chlorine.

    Science.gov (United States)

    Son, Hyunju; Cho, Min; Kim, Jaeeun; Oh, Byungtaek; Chung, Hyenmi; Yoon, Jeyong

    2005-02-01

    To the best of our knowledge, this study is the first investigation to be performed into the potential benefits of mechanically mixed disinfectants in controlling bacterial inactivation. The purpose of this study was to evaluate the disinfection efficiency of mechanically mixed oxidants with identical oxidant concentrations, which were made by adding small amounts of subsidiary oxidants, namely ozone (O3), chlorine dioxide (ClO2), hydrogen peroxide (H2O2) and chlorite (ClO2(-)), to free available chlorine (Cl2), using Bacillus subtilis spores as the indicator microorganisms. The mechanically mixed oxidants containing Cl2/O3, Cl2/ClO2 and Cl2/ClO2(-) showed enhanced efficiencies (of up to 52%) in comparison with Cl2 alone, whereas no significant difference was observed between the mixed oxidant, Cl2/H2O2, and Cl2 alone. This enhanced disinfection efficiency can be explained by the synergistic effect of the mixed oxidant itself and the effect of intermediates such as ClO2(-)/ClO2, which are generated from the reaction between an excess of Cl2 and a small amount of O3/ClO2(-). Overall, this study suggests that mechanically mixed oxidants incorporating excess chlorine can constitute a new and moderately efficient method of disinfection.

  9. Inactivation of Salmonella on Eggshells by Chlorine Dioxide Gas.

    Science.gov (United States)

    Kim, Hyobi; Yum, Bora; Yoon, Sung-Sik; Song, Kyoung-Ju; Kim, Jong-Rak; Myeong, Donghoon; Chang, Byungjoon; Choe, Nong-Hoon

    2016-01-01

    Microbiological contamination of eggs should be prevented in the poultry industry, as poultry is one of the major reservoirs of human Salmonella. ClO2 gas has been reported to be an effective disinfectant in various industry fields, particularly the food industry. The aims of this study were to evaluate the antimicrobial effect of chlorine dioxide gas on two strains of Salmonella inoculated onto eggshells under various experimental conditions including concentrations, contact time, humidity, and percentage organic matter. As a result, it was shown that chlorine dioxide gas under wet conditions was more effective in inactivating Salmonella Enteritidis and Salmonella Gallinarum compared to that under dry conditions independently of the presence of organic matter (yeast extract). Under wet conditions, a greater than 4 log reduction in bacterial populations was achieved after 30 min of exposure to ClO2 each at 20 ppm, 40 ppm, and 80 ppm against S. Enteritidis; 40 ppm and 80 ppm against S. Gallinarum. These results suggest that chlorine dioxide gas is an effective agent for controlling Salmonella, the most prevalent contaminant in the egg industry.

  10. Photochemical reactions among formaldehyde, chlorine, and nitrogen dioxide in air

    Energy Technology Data Exchange (ETDEWEB)

    Hanst, P.L.; Gay, B.W. Jr.

    1977-11-01

    Photochemical reactions among chlorine, nitrogen dioxide, and formaldehyde were studied, using parts-per-million concentrations in 1 atm of air. The reactant mixtures were irradiated by ultraviolet fluorescent lamps and simultaneously analyzed by the Fourier transform infrared technique by use of folded light paths up to 504 m. With an excess of NO/sub 2/ over Cl/sub 2/, the reaction products included O/sub 3/, CO, HNO/sub 3/,N/sub 2/O/sub 5/, HCl, and nitryl chloride (ClNO/sub 2/). When chlorine exceeded NO/sub 2/, the principal product was peroxy nitric acid (HOONO/sub 2/). Peroxy formyl nitrate, nitrous acid, and chlorine nitrate were not seen. The nitryl chloride was stable even with the ultraviolet lights on. The peroxy nitric acid disappeared from the cell with a half-life of about 10 min. Formyl radicals (HCO), unlike acetyl radicals, did not combine with O/sub 2/ and NO/sub 2/ by addition. HCO reacted with O/sub 2/ to yield CO and HO/sub 2/. The HO/sub 2/ will then add to NO/sub 2/ to yield HOONO/sub 2/. If NO is present, the HO/sub 2/ will prefer to react with it, oxidizing it to NO/sub 2/.

  11. Reduction of chlorine dioxide emissions from a Mathieson generator

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, R.

    1998-03-01

    Chlorine dioxide emissions from the ClO{sub 2} Mathison generator at Crestbrook Forest Industries was studied to determine whether changes would be necessary to meet emission restrictions. The effect of water temperature, packing height and chlorine dioxide gas concentration on emissions was determined using the gas sample data and mass transfer equations for the absorption tower and scrubber. Operation of the generator was discovered to have a significant effect on final chlorine dioxide emissions. Final solutions were evaluated based on ensuring compliance as well as minimizing capital cost. The order in which the changes should be performed to ensure compliance was determined to be (1) change in permit restrictions, (2) better operation of the generator, (3) converting the scrubber to operate with water, and (4) souring the vented gas with SO{sub 2} before being scrubbed with caustic. This would reduce emissions to near zero. However, this solution would be effective only if the SO{sub 2} addition were carefully controlled to ensure that no sodium sulphite was produced. 2 refs., 8 figs.

  12. SOME ASPECTS REGARING CHLORINE DECAY IN WATER DISTRIBUTION NETWORKS

    Directory of Open Access Journals (Sweden)

    LIANA IOANA VUŢĂ

    2011-03-01

    Full Text Available A major objective of drinking water treatment is to provide microbiologically safe drinking water. The combination of conventional drinking water treatment and disinfection has proved to be one of the major public health advances in modern times. The quality of drinking water delivered to the customer’s tap is influenced by a number of processes; namely water treatment, disinfection and changes during transport of treated water via the distribution system. All natural waters and even treated drinking water exerts disinfectant demand due to the reactions with NOM and other constituents in water. Therefore, the applied disinfectant dose must be sufficient to meet the inherent demand in the treated water, to provide sufficient protection against microbial infection. Thus, controlling free residual chlorine properly is definitely important to ensure meeting regulatory requirements and satisfying customer needs.This paper presents the main aspects regarding chlorine decay in drinking-water distribution networks and, also a free chlorine decay simulation with EPANET2 on Ramnicu Valcea water distribution system.

  13. Development of industrial catalysts for sustainable chlorine production.

    Science.gov (United States)

    Mondelli, Cecilia; Amrute, Amol P; Moser, Maximilian; Schmidt, Timm; Pérez-Ramírez, Javier

    2012-01-01

    The heterogeneously catalyzed gas-phase oxidation of HCl to Cl(2) offers an energy-efficient and eco- friendly route to recover chlorine from HCl-containing byproduct streams in the chemical industry. This process has attracted renewed interest in the last decade due to an increased chlorine demand and the growing excess of byproduct HCl from chlorination processes. Since its introduction (by Deacon in 1868) and till recent times, the industrialization of this reaction has been hindered by the lack of sufficiently active and durable materials. Recently, RuO(2)-based catalysts with outstanding activity and stability have been designed and they are being implemented for large-scale Cl(2) recycling. Herein, we review the main limiting features of traditional Cu-based catalysts and survey the key steps in the development of the new generation of industrial RuO(2)-based materials. As the expansion of this technology would benefit from cheaper, but comparably robust, alternatives to RuO(2)-based catalysts, a nov el CeO(2)-based catalyst which offers promising perspectives for application in this field has been introduced.

  14. Bioremediation of chlorinated pesticide-contaminated soil using anaerobic sludges and surfactant addition.

    Science.gov (United States)

    Baczynski, Tomasz P; Pleissner, Daniel

    2010-01-01

    Methanogenic granular sludge and wastewater fermented sludge were used as inocula for batch tests of anaerobic bioremediation of chlorinated pesticide contaminated soil. Results obtained for both types of biomass were similar: 80 to over 90% of gamma -hexachlorocyclohexane (gamma-HCH), 1,1,1-trichloro-2,2-bis-(4-methoxyphenyl)ethane (methoxychlor) and 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)ethane (DDT) removed in 4-6 weeks. Residual fractions of these pesticides persisted till the end of the 16-week experiment. DDT was degraded through 1,1-dichloro-2,2-bis-(4-chlorophenyl)ethane (DDD). Accumulation of this product corresponded stoichiometrically only to 34-53% of removed DDT, supposedly due to its further transformations, finally resulting in formation of detected 4,4'-dichlorobenzophenone (DBP). Addition of 0.5 mM Tween 80 nonionic surfactant resulted in about a twofold decrease of gamma -HCH and methoxychlor residual concentrations, as well as considerably lower DDD accumulation (7-29%) and higher DBP production. However, 1.25 mM dose of this surfactant applied together with granular sludge brought DDD levels back to that observed for treatments with the sludge alone, also impairing DBP formation.

  15. Ubiquitous occurrence of chlorinated byproducts of bisphenol A and nonylphenol in bleached food contacting papers and their implications for human exposure.

    Science.gov (United States)

    Zhou, Yuyin; Chen, Mo; Zhao, Fanrong; Mu, Di; Zhang, Zhaobin; Hu, Jianying

    2015-06-16

    The occurrence of bisphenol A (BPA), nonylphenol (NP), and their six chlorinated byproducts were investigated in 74 food contacting papers (FCPs) from China, the U.S.A., Japan, and Europe using a sensitive dansylation LC-MS/MS method. BPA (paper production. The mean concentrations of monochloro-BPA (MCBPA), dichloro-BPA (DCBPA), trichloro-BPA (TCBPA), tetrachloro-BPA (TeCBPA), monochloro-NP (MCNP), and dichloro-NP (DCNP) in bleached FCPs were 0.019 ± 0.025, 0.0033 ± 0.0059, 0.0030 ± 0.0045, 0.0081 ± 0.019, 0.23 ± 0.46, and 0.066 ± 0.11 ng/g, respectively, much higher than those (0.0021 ± 0.0020 ng/g for MCBPA, 0.00068 ± 0.00076 ng/g for DCBPA, chlorinated byproducts could migrate from coffee filters into coffee solution with migration rates of 71 ± 10% for BPA, 2.4 ± 0.33% for NP, 47 ± 1.4% for MCBPA, and 0.35 ± 0.11% for MCNP. This is the first report on the occurrence of chlorinated derivatives of BPA and NP in FCPs and their migration, which provides important information to comprehensively understand human exposure to BPA, NP, and their chlorinated derivatives.

  16. SIMULTANEOUS DETERMINATION OF CHLORINE DIOXIDE AND HYPOCHLOROUS ACID IN BLEACHING SYSTEM

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2011-04-01

    Full Text Available This study has demonstrated a rapid spectroscopic method for the determination of chlorine dioxide and hypochlorous acid concentrations in the pulp bleaching processes. It was found that chlorine dioxide and hypochlorous acid have an isosbestic wavelength of 295 nm. The soluble lignin in such a system is the main interference, but can be corrected by determining the absorbances at 295 nm, 380 nm, and 480 nm. Thus, based on the spectroscopic measurements at 295 nm (the isosbestic point wavelength for chlorine dioxide and hypochlorous acid, 380 nm (absorbance wavelength of chlorine dioxide and 480 nm (the acid soluble lignin absorbance wavelength, the chlorine dioxide and hypochlorous acid concentrations in the bleaching process can be quantified. However, hypochlorous acid was not detected in the real bleaching effluent for its low content. The present method is simple, rapid, accurate, and has the potential for on-line monitoring of the chlorine dioxide bleaching process.

  17. Research of chemical induction unit on mixing effect and chlorine saving

    Institute of Scientific and Technical Information of China (English)

    Jiao Zhongzhi; Chen Zhonglin; Li ZuoLiang; Xue Zhu; Yuan Xing; Li Guibai

    2007-01-01

    Rapid mixing and chlorine saving are two important problems that most drinking water industries ale focus on, and this paper adopts chemical induction unit to compare with water jet injector to study what merits chemical induction unit has. The experiment chose coefficient of variability of chlorine concentration to evaluate the mix effect and used chlorine consumption to compare the two equipments. Distribution reservoir experiments show that chemical induction unit can completely mix chlorine less than 6. 2 seconds and water jet injector can not completely mix in 3 minutes. Mixing pool experiments show that chemical induction unit can save chlorine compared with water jet injector, and Can save mole if mole chlorine is consumed.

  18. Assessing chlorinated ethene degradation in a large scale contaminant plume by dual carbon–chlorine isotope analysis and quantitative PCR

    DEFF Research Database (Denmark)

    Hunkeler, D.; Abe, Y.; Broholm, Mette Martina

    2011-01-01

    reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of 13C in the daughter products followed by an enrichment of 13C as degradation proceeded. At 1000 m downgradient...... traditional approaches can be used to gain detailed insight into the processes that control the fate of chlorinated ethenes in large scale plumes....

  19. Impact of January 2005 solar proton events on chlorine species

    Directory of Open Access Journals (Sweden)

    A. Damiani

    2012-05-01

    Full Text Available Sudden changes in stratospheric chlorine species in the polar northern atmosphere, caused by the Solar Proton Events (SPEs of 17 and 20 January 2005, have been investigated and compared with version 4 of the Whole Atmosphere Community Climate Model (WACCM4. We used Aura Microwave Limb Sounder (MLS measurements to monitor the variability of ClO, HCl, HOCl and Michelson Interferometer for Passive Atmospheric Sounder (MIPAS on ENVISAT to retrieve ClONO2. SPE-induced chlorine activation has been identified. HCl decrease occurred at nearly all the investigated altitudes (i.e., 10–0.5 hPa with the strongest decrease (of about 0.25 ppbv on 21 January. HOCl was found to be the main active chlorine species under nighttime conditions (with increases of more than 0.2 ppbv whereas both HOCl and ClO enhancements (about 0.1 ppbv have been observed at the polar night terminator. Further, small ClO decreases (of less than 0.1 ppbv and ClONO2 enhancements (about 0.2 ppbv have been observed at higher latitudes (i.e., at nighttime roughly above 2 hPa.

    While WACCM4 reproduces most of the SPE-induced variability in the chlorine species fairly well, in some particular regions discrepancies between the modeled and measured temporal evolution of the abundances of chlorine species were found. HOCl changes are modelled very well with respect to both magnitude and geographic distribution. ClO decreases are reproduced at high latitudes, whereas ClO enhancements in the terminator region are underestimated and attributed to background variations. WACCM4 also reproduces the HCl depletion in the mesosphere but it does not show the observed decrease below about 2 hPa. Finally, WACCM4 simulations indicate that the observed ClONO2 increase is dominated by background variability, although SPE-induced production might contribute by 0.1 ppbv.

  20. Resistance and Inactivation Kinetics of Bacterial Strains Isolated from the Non-Chlorinated and Chlorinated Effluents of a WWTP

    Science.gov (United States)

    Martínez-Hernández, Sylvia; Vázquez-Rodríguez, Gabriela A.; Beltrán-Hernández, Rosa I.; Prieto-García, Francisco; Miranda-López, José M.; Franco-Abuín, Carlos M.; Álvarez-Hernández, Alejandro; Iturbe, Ulises; Coronel-Olivares, Claudia

    2013-01-01

    The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains), Enterobacter cloacae, Kluyvera cryocrescens (three strains), Kluyvera intermedia, Citrobacter freundii (two strains), Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L−1), contact time (0, 15 and 30 min) and water temperature (20, 25 and 30 °C). The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L−1 dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L−1 with various retention times (0, 10, 20, 30, 60 and 90 min). The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments. PMID:23924881

  1. Resistance and Inactivation Kinetics of Bacterial Strains Isolated from the Non-Chlorinated and Chlorinated Effluents of a WWTP

    Directory of Open Access Journals (Sweden)

    Claudia Coronel-Olivares

    2013-08-01

    Full Text Available The microbiological quality of water from a wastewater treatment plant that uses sodium hypochlorite as a disinfectant was assessed. Mesophilic aerobic bacteria were not removed efficiently. This fact allowed for the isolation of several bacterial strains from the effluents. Molecular identification indicated that the strains were related to Aeromonas hydrophila, Escherichia coli (three strains, Enterobacter cloacae, Kluyvera cryocrescens (three strains, Kluyvera intermedia, Citrobacter freundii (two strains, Bacillus sp. and Enterobacter sp. The first five strains, which were isolated from the non-chlorinated effluent, were used to test resistance to chlorine disinfection using three sets of variables: disinfectant concentration (8, 20 and 30 mg·L−1, contact time (0, 15 and 30 min and water temperature (20, 25 and 30 °C. The results demonstrated that the strains have independent responses to experimental conditions and that the most efficient treatment was an 8 mg·L−1 dose of disinfectant at a temperature of 20 °C for 30 min. The other eight strains, which were isolated from the chlorinated effluent, were used to analyze inactivation kinetics using the disinfectant at a dose of 15 mg·L−1 with various retention times (0, 10, 20, 30, 60 and 90 min. The results indicated that during the inactivation process, there was no relationship between removal percentage and retention time and that the strains have no common response to the treatments.

  2. Development of a system for "in situ" determination of chlorinated hydrocarbons in groundwater

    OpenAIRE

    Boutsiadou, Xanthippe; Hunkeler, Daniel

    2012-01-01

    Volatile organic compounds (VOCs), and especially chlorinated hydrocarbons, are common groundwater contaminants. Efficient monitoring that can be conducted directly in the field is needed to detect a possible pollution by organic contaminants such as chlorinated hydrocarbons. The general aim of this project is to develop a portable instrument for the in situ measurement of chlorinated hydrocarbons in groundwater. The instrument relies on the transfer of volatile organic compounds to the gas p...

  3. Synergistic prevention of biofouling in seawater desalination by zwitterionic surfaces and low-level chlorination.

    Science.gov (United States)

    Yang, Rong; Jang, Hongchul; Stocker, Roman; Gleason, Karen K

    2014-03-19

    Smooth, durable, ultrathin antifouling layers are deposited onto commercial reverse osmosis membranes without damaging them and they exhibit a fouling reduction. A new synergistic approach to antifouling, by coupling surface modification and drinking-water-level chlorination is enabled by the films' unique resistance against chlorine degradation. This approach substantially enhances longer-term fouling resistance compared with surface modification or chlorination alone, and can reduce freshwater production cost and its collateral toxicity to marine biota.

  4. Use of integrated cell culture-PCR to evaluate the effectiveness of poliovirus inactivation by chlorine.

    Science.gov (United States)

    Blackmer, F; Reynolds, K A; Gerba, C P; Pepper, I L

    2000-05-01

    Current standards, based on cell culture assay, indicate that poliovirus is inactivated by 0.5 mg of free chlorine per liter after 2 min; however, integrated cell culture-PCR detected viruses for up to 8 min of exposure to the same chlorine concentration, requiring 10 min for complete inactivation. Thus, the contact time for chlorine disinfection of poliovirus is up to five times greater than previously thought.

  5. Some kinetics aspects of chlorine-solids reactions

    Directory of Open Access Journals (Sweden)

    Kanari, N.

    2010-02-01

    Full Text Available The present paper describes detailed kinetics investigations on some selected chlorine-solid reactions through thermogravimetric measurements. The solids studied in this article include chemical pure oxides and sulfides as well as their natural bearing materials. The chlorinating agents employed are gaseous mixtures of Cl2+N2 (chlorination, Cl2+O2 (oxychlorination, and Cl2+CO (carbochlorination. Results are presented as effects of various parameters on the reaction rate of these solids with these chlorinating agents. It was observed that the reactivity of these solids towards different chlorinating agents varied widely. Sulfides could be chlorinated at room temperature, while carbochlorination of chromium (III oxide was possible only above 500 °C. The variation of the chlorination rate of these complex materials with respect to gas velocity, composition and temperature enabled us to focus some light on the plausible reaction mechanisms and stoichiometries. The obtained results were used for selective removal of iron from chromite concentrates, extraction of valuable metals from sulfide materials, purification of MgO samples, etc.

    Este trabajo describe detalladas investigaciones cinéticas en algunas reacciones seleccionadas de cloro-sólido a través de medidas termogravimétricas. Los sólidos estudiados en este artículo incluyen óxidos químicos puros y sulfuros, así como sus materiales naturales de soporte. Los agentes de cloración empleados son mezclas de gases de Cl2+N2 (cloración, Cl2+O2 (oxicloración y Cl2+O2 (carbocloración. Los resultados se presentan como efecto de varios parámetros en el porcentaje de reacción de estos sólidos con los agentes de cloración. Se ha observado que la reactividad de estos sólidos a través de diferentes agentes de cloración varía ampliamente. Los sulfuros se pudieron

  6. 46 CFR 46.15-5 - Engineering requirements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Engineering requirements. 46.15-5 Section 46.15-5... Lakes Voyages § 46.15-5 Engineering requirements. (a) Bilge and ballast systems, piping, inlets and... subchapter F (Marine Engineering) of this chapter....

  7. Evaluating potential chlorinated methanes degradation mechanisms and treatments in interception trenches filled with concrete-based construction wastes

    Science.gov (United States)

    Rodríguez-Fernandez, Diana; Torrentó, Clara; Rosell, Mònica; Audí-Miró, Carme; Soler, Albert

    2014-05-01

    conditions in the trenches with in situ chemical oxidation (ISCO), which would be able to remove the rest of the accompanying pollutants, is proposed and merits evaluation. Preliminary batch experiments were performed to evaluate the feasibility of different chemical oxidation reactions (permanganate, persulphate, hydrogen peroxide and Fenton) on the complex contaminated recharge water which were, in general, more effective for degrading the chlorinated ethenes than for the chlorinated methanes (Torrentó et al. EGU 2012). Therefore, this study seeks to improve the understanding of CF and CT degradation mechanisms/processes that are going on in the interception trenches as well as to select between the two most effective chemical oxidation remediation treatments (persulphate and permanganate) taking into account their efficiency respect the chlorinated methanes removal, the generated acute toxicity and the applicability of the carbon isotopic fractionation as an indicator of the effectiveness of the future in situ remediation. Additionally, ongoing batch experiments are expected to elucidate if CT is undergoing abiotic reductive dechlorination by Fe-bearing minerals such as hydrophobic green rust (Ayala-Luis et al., 2012) which transform CT into non-chlorinated substances such as formic acid and carbon monoxide. This unstable iron compound might be formed in the interception trenches during chloride induced corrosion of iron mineral phases present in the concrete-based construction wastes (Sagoe-Crentsil and Glasser, 1993). The role of other minerals like iron oxy-hydroxides, carbonates or sulphides cannot be discarded at all. The potential of δ13C values to assess the efficiency of this abiotic CT degradation reaction will be also evaluated. References Ayala-Luis, K.; Cooper, N.; Bender C. and Hansen. H. (2012) Efficient dechlorination of carbon tetrachloride by hydrophobic green rust intercaled with dodecanoate anions. Environmental Science & Technology 46, 3390

  8. Safety and environmental aspects of zinc--chlorine hydrate batteries for electric-vehicle applications

    Energy Technology Data Exchange (ETDEWEB)

    Kodali, S.; Henriksen, G.L.; Whittlesey, C.C.; Warde, C.J.; Carr, P.; Symons, P.C.

    1978-03-01

    Public acceptance of high-performance cost-effective zinc--chlorine hydrate batteries for the random-use electric-vehicle application will require meeting stringent safety and environmental requirements. These requirements revolve mainly around the question of accidental release and spread of toxic amounts of chlorine gas, the only potential hazard in this battery system. Available information in the areas of physiological effects, environmental impact, and governmental regulation of chlorine were reviewed. The design, operation, and safety features of a first commercial electric-vehicle battery were conceived and analyzed from the chlorine release aspect. Two types of accident scenarios were analyzed in terms of chlorine release rates, atmospheric dispersion, health hazard, and possible clean-up operations. The worst-case scenario, a quite improbable accident, involves the spillage of chlorine hydrate onto the ground, while the other scenario, a more probable accident, involves the release of chlorine gas from a ruptured battery case. Heat-transfer and chlorine-dispersion models, developed to analyze these scenarios, establish a firm basis for a comprehenive and factual position statement on this topic. The results of this preliminary study suggest that electric vehicles powered by appropriately designed zinc--chlorine hydrate batteries will pose negligible health or environmental hazards on the nation's streets and highways. 8 figures, 14 tables.

  9. The role of bound chlorine in the brightness reversion of bleached hardwood kraft pulp

    Directory of Open Access Journals (Sweden)

    Kátia Maria Morais Eiras

    2009-01-01

    Full Text Available Our previous paper showed fragmentary evidence that pulp brightness reversion may be negatively affected by its organically bound chlorine (OX content. A thorough investigation on eucalyptus kraft pulp led to the conclusion that OX increases reversion of certain pulps but this trend is not universal. Alkaline bleaching stages decrease reversion regardless of pulp OX content. Pulps bleached with high temperature chlorine dioxide revert less than those bleached with conventional chlorine dioxide in sequences ending with a chlorine dioxide stage but similarly in sequences ending with a final peroxide stage. The use of secondary condensate for pulp washing decreases reversion.

  10. "Cromoglycate: A healing agent in acute Chlorine-induced lung damage "

    Directory of Open Access Journals (Sweden)

    "Pipelzadeh MH

    2002-09-01

    Full Text Available In the present study the effectiveness of sodium cromoglycate in treatment of alveolar damage induced by chlorine gas in rats was investigated. Chlorine was generated by chemical interaction between potassium permanganate and concentrated hydrochloric acid. The rats were exposed to sublethal dose of chlorine gas. Treatment with 2.5 mg of 1 ml nebulized sodium cromoglycate solution over 5 minutes was initiated 30 minutes after exposure followed by twice daily treatment for 21 days. Results of this study show that cromoglycate reduced alveolar thickness, septal rupture, hemorrhage and detachment of the epithelial lining of the bronchioles induced by chlorine gas.

  11. A Visible-Light-Induced α-H Chlorination of Alkylarenes with Inorganic Chloride under NanoAg@AgCl.

    Science.gov (United States)

    Liu, Shouxin; Zhang, Qi; Li, Huiying; Yang, Yihua; Tian, Xia; Whiting, Andrew

    2015-06-26

    An efficient, photocatalytic chlorination of alkylarene α-H groups using NaCl/HCl as a chlorine source has been developed, which involves a radical mechanism under visible-light (including sunlight) conditions. A chlorine radical is proposed to be formed by an electron transfer from chloride ion to O2 in air through the bandgap hole of the semiconductor AgCl. The chlorination protocol is characterized by its use of natural sunlight or other visible light, mild conditions, cheap source of chlorine, green solvent, and high selectivity. The yield of benzylchloride is 95% with a toluene conversion as high as 40%, which rivals traditional chlorination methods.

  12. Levels and profiles of chlorinated and brominated contaminants in Southern Hemisphere humpback whales, Megaptera novaeangliae.

    Science.gov (United States)

    Dorneles, Paulo R; Lailson-Brito, José; Secchi, Eduardo R; Dirtu, Alin C; Weijs, Liesbeth; Dalla Rosa, Luciano; Bassoi, Manuela; Cunha, Haydée A; Azevedo, Alexandre F; Covaci, Adrian

    2015-04-01

    The study documents the levels and profiles of selected contaminants [polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs) and methoxylated PBDEs (MeO-PBDEs)] in blubber biopsy samples collected from humpback whales (Megaptera novaeangliae) in Antarctic Peninsula waters. In addition, we investigated year-to-year and sex-related differences in the bioaccumulation patterns. Except for hexachlorobenzene (HCB), whose concentrations were in the same range as those found in whales from the Northern Hemisphere, levels of all other compounds were lower in Southern Hemisphere whales compared to literature data on animals from the Arctic and subarctic region. The mean contribution to the sum of all anthropogenic organohalogen compounds (ΣOHC) decreased in the following order ΣPCBs (44%)>HCB (31%)>ΣDDXs (13%)>ΣCHLs (4.6%)>ΣHCHs (4.4%)>ΣPBDEs (0.9%). The predominant compounds within each chemical class were: PCBs 153, 149, 101 and 138; p,p'-DDE; γ-HCH; trans-nonachlor; PBDEs 99 and 47. The most dominant MeO-PBDE congener was 6-MeO-BDE 47. As samples were collected during three consecutive summer seasons, year-to-year trends could be assessed indicating a significant decrease from 2000 to 2003 for ΣCHL levels. Higher ΣPBDE concentrations and higher values of the ΣPBDE / ΣMeO-PBDE ratio, as well as higher ratios between the two MeO-BDEs (2'-MeO-BDE 68/6-MeO-BDE 47) were found in females compared to males. Higher ΣMeO-PBDE concentrations and higher values of the ratios between the lower chlorinated and the higher chlorinated PCBs were found in males than in females. In addition, five out of six significant differences found through discriminant function analysis were gender-related. The literature reports both feeding in mid- to low-latitudes and sex-related differences in migration patterns for humpback whales from the Southern Hemisphere, indicating that the hypothesis of dietary differences between males and

  13. UV enhanced gas-solid synthesis of chlorinated poly vinyl chloride characterized by a UV-Vis online analysis method☆

    Institute of Scientific and Technical Information of China (English)

    Qianli Yang; Wei Lu; Lin Bai; Binhang Yan; Yi Cheng

    2015-01-01

    Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly. Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reac-tion once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature (Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.

  14. Metals releases and disinfection byproduct formation in domestic wells following shock chlorination

    Directory of Open Access Journals (Sweden)

    M. Walker

    2010-06-01

    Full Text Available Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 ppm in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We carried out experiments with four wells to observe and determine the persistence of increased concentrations of metals and disinfection byproducts. Water samples from shock chlorinated wells were analyzed for Pb, Cu, As, radionuclides and disinfection byproducts (haloacetic acids and trihalomethanes, immediately prior to treatment, after sufficient contact time with chlorine had elapsed, and at intervals determined by the number of casing volumes purged, for up to four times the well casing volume.

    Elevated concentrations of lead and copper dissipated in proportion to free chlorine (measured semi-quantitatively during the purging process. Trihalomethanes and haloacetic acids were formed in wells during disinfection. In one of two wells tested, disinfection byproducts dissipated in proportion to free chlorine during purging. However, one well retained disinfection byproducts and free chlorine after four well volumes had been purged. Although metals returned to background concentrations in this well, disinfection byproducts remained elevated, though below the MCL, likely because purging volume was insufficient. Simple chlorine test strips may be a useful method for indicating when purging is adequate to remove metals and disinfection by-products mobilized and formed by shock chlorination.

  15. Metals releases and disinfection byproduct formation in domestic wells following shock chlorination

    Directory of Open Access Journals (Sweden)

    M. Walker

    2011-01-01

    Full Text Available Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 mg L−1 in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We carried out experiments with four wells to observe and determine the persistence of increased concentrations of metals and disinfection byproducts. Water samples from shock chlorinated wells were analyzed for Pb, Cu, As, radionuclides and disinfection byproducts (haloacetic acids and trihalomethanes, immediately prior to treatment, after sufficient treatment time with chlorine had elapsed, and at intervals determined by the number of casing volumes purged, for up to four times the well casing volume.

    Elevated concentrations of lead and copper dissipated in proportion to free chlorine (measured semi-quantitatively during the purging process. Trihalomethanes and haloacetic acids were formed in wells during disinfection. In one of two wells tested, disinfection byproducts dissipated in proportion to free chlorine during purging. However, one well retained disinfection byproducts and free chlorine after 4 WV had been purged. Although metals returned to background concentrations in this well, disinfection byproducts remained elevated, though below the MCL. This may have been due to well construction characteristics and interactions with aquifer materials. Simple chlorine test strips may be a useful method for indicating when purging is adequate to remove metals and disinfection by-products mobilized and formed by shock chlorination.

  16. A new formulation of equivalent effective stratospheric chlorine (EESC

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2007-09-01

    Full Text Available Equivalent effective stratospheric chlorine (EESC is a convenient parameter to quantify the effects of halogens (chlorine and bromine on ozone depletion in the stratosphere. We show, discuss, and analyze a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This EESC can be more appropriately applied to various parts of the stratosphere because of this dependence on mean age-of-air. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. In this paper, we first provide a detailed description of the EESC calculation. We then use this EESC formulation to estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties and possible problems in the estimated times of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air and fractional release values, and the assumption that these quantities are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be significantly accelerated.

  17. Suppression of chlorine activation on aviation-produced volatile particles

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-07-01

    Full Text Available We examine the effect of nm-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC and a chemical box model. We confirm large scale model results that at temperatures T > 210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (< 210 K we isolate two effects which efficiently reduce the aircraft-induced perturbation: (1 background particles growth due to H2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2 the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and ozone depletion. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.

  18. Suppression of chlorine activation on aviation-produced volatile particles

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-01-01

    Full Text Available We examine the effect of nanometer-sized aircraft-induced aqueous sulfuric acid (H2SO4/H2O particles on atmospheric ozone as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate surface area density due to air traffic in the North Atlantic Flight Corridor (NAFC and a chemical box model. We confirm large scale model results that at temperatures T>210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area. However, at lower temperatures (2O and HNO3 uptake enhance scavenging losses of aviation-produced liquid particles and (2 the Kelvin effect efficiently limits chlorine activation on the small aircraft-induced droplets by reducing the solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile aerosols under cold conditions. In contrast we find contrail ice particles to be potentially important for heterogeneous chlorine activation and reductions in ozone levels. These features have not been taken into consideration in previous global studies of the atmospheric impact of aviation. Therefore, to parameterize them in global chemistry and transport models, we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area increase, and neglect heterogeneous chlorine reactions on liquid plume particles but not on ice contrails and aircraft induced ice clouds.

  19. Modeling Penicillium expansum resistance to thermal and chlorine treatments.

    Science.gov (United States)

    Salomão, Beatriz C M; Churey, John J; Aragão, Gláucia M F; Worobo, Randy W

    2009-12-01

    Apples and apple products are excellent substrates for Penicillium expansum to produce patulin. In an attempt to avoid excessive levels of patulin, limiting or reducing P. expansum contamination levels on apples designated for storage in packinghouses and/or during apple juice processing is critical. The aim of this work was (i) to determine the thermal resistance of P. expansum spores in apple juice, comparing the abilities of the Bigelow and Weibull models to describe the survival curves and (ii) to determine the inactivation of P. expansum spores in aqueous chlorine solutions at varying concentrations of chlorine solutions, comparing the abilities of the biphasic and Weibull models to fit the survival curves. The results showed that the Bigelow and Weibull models were similar for describing the heat inactivation data, because the survival curves were almost linear. In this case, the concept of D- and z-values could be used, and the D-values obtained were 10.68, 6.64, 3.32, 1.14, and 0.61 min at 50, 52, 54, 56, and 60 degrees C, respectively, while the z-value was determined to be 7.57 degrees C. For the chlorine treatments, although the biphasic model gave a slightly superior performance, the Weibull model was selected, considering the parsimony principle, because it has fewer parameters than the biphasic model has. In conclusion, the typical pasteurization regimen used for refrigerated apple juice (71 degrees C for 6 s) is capable of achieving a 6-log reduction of P. expansum spores.

  20. Iron-carbon composites for the remediation of chlorinated hydrocarbons

    Science.gov (United States)

    Sunkara, Bhanu Kiran

    This research is focused on engineering submicron spherical carbon particles as effective carriers/supports for nanoscale zerovalent iron (NZVI) particles to address the in situ remediation of soil and groundwater chlorinated contaminants. Chlorinated hydrocarbons such as trichloroethylene (TCE) and tetrachloroethylene (PCE) form a class of dense non-aqueous phase liquid (DNAPL) toxic contaminants in soil and groundwater. The in situ injection of NZVI particles to reduce DNAPLs is a potentially simple, cost-effective, and environmentally benign technology that has become a preferred method in the remediation of these compounds. However, unsupported NZVI particles exhibit ferromagnetism leading to particle aggregation and loss in mobility through the subsurface. This work demonstrates two approaches to prepare carbon supported NZVI (iron-carbon composites) particles. The objective is to establish these iron-carbon composites as extremely useful materials for the environmental remediation of chlorinated hydrocarbons and suitable materials for the in situ injection technology. This research also demonstrates that it is possible to vary the placement of iron nanoparticles either on the external surface or within the interior of carbon microspheres using a one-step aerosol-based process. The simple process of modifying iron placement has significant potential applications in heterogeneous catalysis as both the iron and carbon are widely used catalysts and catalyst supports. Furthermore, the aerosol-based process is applied to prepare new class of supported catalytic materials such as carbon-supported palladium nanoparticles for ex situ remediation of contaminated water. The iron-carbon composites developed in this research have multiple functionalities (a) they are reactive and function effectively in reductive dehalogenation (b) they are highly adsorptive thereby bringing the chlorinated compound to the proximity of the reactive sites and also serving as adsorption

  1. Chlorine decay under steady and unsteady-state hydraulic conditions

    DEFF Research Database (Denmark)

    Stoianov, Ivan; Aisopou, Angeliki

    2014-01-01

    This paper describes a simulation framework for the scale-adaptive hydraulic and chlorine decay modelling under steady and unsteady-state flows. Bulk flow and pipe wall reaction coefficients are replaced with steady and unsteady-state reaction coefficients. An unsteady decay coefficient is defined...... which depends upon the absolute value of shear stress and the rate of change of shear stress for quasi-unsteady and unsteady-state flows. A preliminary experimental and analytical investigation was carried out in a water transmission main. The results were used to model monochloramine decay...

  2. Native sulfur/chlorine SAD phasing for serial femtosecond crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Nakane, Takanori [The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Song, Changyong [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); POSTECH, Pohang 790-784 (Korea, Republic of); Suzuki, Mamoru [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nango, Eriko; Kobayashi, Jun [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Masuda, Tetsuya [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Inoue, Shigeyuki [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mizohata, Eiichi [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nakatsu, Toru [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Tanaka, Tomoyuki; Tanaka, Rie [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Shimamura, Tatsuro [Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Hatsui, Takaki; Yabashi, Makina [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Nureki, Osamu [The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Iwata, So [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Sugahara, Michihiro, E-mail: msuga@spring8.or.jp [RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

    2015-11-27

    Sulfur SAD phasing facilitates the structure determination of diverse native proteins using femtosecond X-rays from free-electron lasers via serial femtosecond crystallography. Serial femtosecond crystallography (SFX) allows structures to be determined with minimal radiation damage. However, phasing native crystals in SFX is not very common. Here, the structure determination of native lysozyme from single-wavelength anomalous diffraction (SAD) by utilizing the anomalous signal of sulfur and chlorine at a wavelength of 1.77 Å is successfully demonstrated. This sulfur SAD method can be applied to a wide range of proteins, which will improve the determination of native crystal structures.

  3. Theoretical study of the thermochemistry of chlorine oxyfluorides

    Science.gov (United States)

    Sánchez, Hernán R.; Del Pla, Julián

    2016-10-01

    There is a lack of experimental thermochemical values for most chlorine oxyfluorides. Previous high level theoretical, CCSD(T), results showed uncommonly large errors in the standard heats of formation calculated through the atomization method. We propose that the differences are due to unusually large contributions to energy from higher excitations within the coupled cluster framework, and we tackle the problem by using a calculation scheme based on isodesmic reactions. Our suspicions are supported by results of static correlation diagnostics. Our final recommended values are in better agreement with the experimental data available. Other thermodynamic properties are also calculated.

  4. Variations in isotopic compositions of chlorine in evaporation-controlled salt lake brines of Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Xiao, Ying-kai; Liu, Wei-guo; Zhou, Y.M.; Wang, Yun-hui; Shirodkar, P.V.

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs sub(2) Cl sup(+) ion by thermal ionization...

  5. Microbial respiration with chlorine oxyanions: diversity and physiological and biochemical properties of chlorate- and perchlorate-reducing microorganisms

    NARCIS (Netherlands)

    Liebensteiner, M.G.; Oosterkamp, M.J.; Stams, A.J.M.

    2016-01-01

    Chlorine oxyanions are valuable electron acceptors for microorganisms. Recent findings have shed light on the natural formation of chlorine oxyanions in the environment. These suggest a permanent introduction of respective compounds on Earth, long before their anthropogenic manufacture. Microorganis

  6. Second-Order Chlorine Decay and Trihalomethanes Formation in a Pilot-Scale Water Distribution Systems

    Science.gov (United States)

    It is well known that model-building of chlorine decay in real water distribution systems is difficult because chlorine decay is influenced by many factors (e.g., bulk water demand, pipe-wall demand, piping material, flow velocity, and residence time). In this paper, experiments ...

  7. Effect of chlorine, blanching, freezing, and microwave heating on Cryptosporidium parvum viability inoculated on green peppers.

    Science.gov (United States)

    Duhain, G L M C; Minnaar, A; Buys, E M

    2012-05-01

    Cryptosporidium parvum oocysts have been found on the surface of vegetables in both developed and developing countries. C. parvum can contaminate vegetables via various routes, including irrigation water. This study investigated the effect of individual treatments of chlorine, blanching, blast freezing, and microwave heating, as well as combined treatments of chlorine and freezing, and chlorine and microwave heating on the viability of C. parvum oocysts inoculated on green peppers. The viability of the oocysts after the treatments was assessed using propidium iodide and a flow cytometer. Based on the propidium iodide staining, the chlorine treatments did not affect the viability of the oocysts. Blast freezing significantly inactivated 20% of the oocysts. Microwave heating and blanching significantly inactivated 93% of oocysts. Treatment with chlorine followed by blast freezing did not affect the viability of the oocysts significantly. Treatment with chlorine and microwave heating was significantly more effective than microwave heating alone and inactivated 98% of the oocysts. The study indicates that C. parvum oocysts are sensitive to heat and, to some extent, to blast freezing, but are resistant to chlorine. Therefore, the use of chlorine during vegetable processing is not a critical control point for C. parvum oocysts, and the consumption of raw or minimally processed vegetables may constitute a health risk as C. parvum oocysts can still be found viable on ready-to-eat, minimally processed vegetables.

  8. Organocatalytic Asymmetric α-Chlorination of 1,3-Dicarbonyl Compounds Catalyzed by 2-Aminobenzimidazole Derivatives

    Directory of Open Access Journals (Sweden)

    Daniel Serrano Sánchez

    2016-01-01

    Full Text Available Bifunctional chiral 2-aminobenzimidazole derivatives 1 and 2 catalyze the enantioselective stereodivergent α-chlorination of β-ketoesters and 1,3-diketone derivatives with up to 50% ee using N-chlorosuccinimide (NCS or 2,3,4,4,5,6-hexachloro-2,5-cyclohexadien-1-one as electrophilic chlorine sources.

  9. Effect of X-ray Contrast Media, Chlorination, and Chloramination on Zebrafish Development

    Science.gov (United States)

    Effect of X-ray Contrast Media, Chlorination, and Chloramination on Zebrafish Development Little is known about the vertebrate developmental toxicity of chlorinated or chloraminated drinking water (DW), iodinated X-ray contrast media (ICM, a common contaminate of DW) or how the c...

  10. Formation and detoxification of reactive intermediates in the metabolism of chlorinated ethenes

    NARCIS (Netherlands)

    Vlieg, JETV; Janssen, DB; Hylckama Vlieg, Johan E.T. van

    2001-01-01

    Short-chain halogenated aliphatics, such as chlorinated ethenes, constitute a large group of priority pollutants. This paper gives an overview on the chemical and physical properties of chlorinated aliphatics that are critical in determining their toxicological characteristics and recalcitrance to b

  11. Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation.

    Science.gov (United States)

    Sorlini, Sabrina; Gialdini, Francesca; Biasibetti, Michela; Collivignarelli, Carlo

    2014-05-01

    Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%.

  12. Corrosion of stainless steels by sulphur dioxide and chlorine in atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.; Dhirendra, Dr.; Sanyal, B.; Pandey, G.N.

    1982-10-01

    This paper deals with the effect of sulphur dioxide and chlorine on stainless steels (AISI 304 and 321) under different atmospheric conditions. 70% RH value was found to be critical giving maximum corrosion. Potassium dichromate has been found to be a suitable passivating agent for protection against corrosion due to chlorine. (5 refs.)

  13. Analysis of the sporicidal activity of chlorine dioxide disinfectant against Bacillus anthracis (Sterne strain)

    Science.gov (United States)

    Chatuev, B.A.; Peterson, J.W.

    2009-01-01

    Summary Routine surface decontamination is an essential hospital and laboratory procedure, but the list of effective, noncorrosive disinfectants that kill spores is limited. We investigated the sporicidal potential of an aqueous chlorine dioxide solution and encountered some unanticipated problems. Quantitative bacteriological culture methods were used to determine the log10 reduction of Bacillus anthracis (Sterne strain) spores following 3 min exposure to various concentrations of aqueous chlorine dioxide solutions at room temperature in sealed tubes, as well as spraying onto plastic and stainless steel surfaces in a biological safety cabinet. Serial 10-fold dilutions of the treated spores were then plated on 5% sheep blood agar plates, and the survivor colonies were enumerated. Disinfection of spore suspensions with aqueous chlorine dioxide solution in sealed microfuge tubes was highly effective, reducing the viable spore counts by 8 log10 in only 3 min. By contrast, the process of spraying or spreading the disinfectant onto surfaces resulted in only a 1 log10 kill because the chlorine dioxide gas was rapidly vaporised from the solutions. Full potency of the sprayed aqueous chlorine dioxide solution was restored by preparing the chlorine dioxide solution in 5% bleach (0.3% sodium hypochlorite). The volatility of chlorine dioxide can cause treatment failures that constitute a serious hazard for unsuspecting users. Supplementation of the chlorine dioxide solution with 5% bleach (0.3% sodium hypochlorite) restored full potency and increased stability for one week. PMID:20061062

  14. EFFECT OF THE DECHLORINATING AGENT, ASCORBIC ACID, ON THE MUTAGENICITY OF CHLORINATED WATER SAMPLES

    Science.gov (United States)

    XAD resin adsorption has been widely used to concentrate the organic compounds present in chlorinated drinking waters prior to mutagenicity testing. Previous work has shown that mutagenic artifcats can arise due to the reaction of residual chlorine with the resins. Althrough the ...

  15. ASCORBIC ACID REDUCTION ON RESIDUAL ACTIVE CHLORINE IN POTABLE WATER PRIOR TO HALOCARBOXYLATE DETERMINATION

    Science.gov (United States)

    In studies on the formation of disinfection byproducts (DBPs), it is necessary to scavenge residual active (odxidizing) chlorine in order to fix the chlorination byproducts (such as haloethanoates) at a point in time . Such research projects often have distinct needs from requi...

  16. ASCORBIC ACID REDUCTION OF RESIDUAL ACTIVE CHLORINE IN POTABLE WATER PRIOR TO HALOCARBOXYLATE DETERMINATION

    Science.gov (United States)

    In studies on the formation of disinfection byproducts (DBPs), it is necessary to scavenge residual active (oxidizing) chlorine in order to fix the chlorination byproducts (such as haloethanoates) at a point in time. Thus, methods designed for compliance monitoring are not alway...

  17. Characterization of chlorinated tire-derived mesoporous activated carbon for adsorptive removal of toluene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jianzhong [College of Environment, HoHai University, Nanjing (China); Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO (United States); Liang, Hao [Logistic Department of Guangzhou Military District, Guangzhou (China); Fang, Jun [Delon Hampton and Associates District of Columbia Water and Sewer Authority, Washington, DC (United States); Zhu, Jianguo [Wistron NeWeb (Kunshan) Corporation, Kunshan, Jiangsu Province (China); Shi, Buchang [Department of Chemistry, Western Kentucky University, Bowling Green, KY (United States)

    2011-06-15

    A series of chlorinated mesoporous activated carbons were derived from waste tires by pyrolysis, activation, and chlorination at different temperatures. The physical and chemical properties of the samples were studied by Brunauer-Emmett-Teller (BET) analysis, Fourier Transform IR Spectroscopy (FT-IR), point of zero charge measurement, thermogravimetric analysis, and by testing their behavior as adsorbents for toluene removal. Our results showed that the tire-derived activated carbon samples have highly mesoporous volumes and surface areas, and chlorination treatment has a slight effect on the pore structure. Lewis acidity of the sample increases after chlorination and the chlorine content increases from 0.24 to 2.32% with chlorination temperature increasing from 50 to 400 C. The higher the chlorine content, the more is the toluene adsorption. In comparison with the commercial carbon (F-400), all the samples have significantly higher adsorption capacity for toluene due to the presence of mesopores, inductive effect of the partial positive chemisorbed chlorine and resonance effects of C-Cl structures. The mesopores probably render easier diffusion of toluene molecule to inner carbon matrix and the strong {pi}-{pi} interaction between toluene and C-Cl resonance structure in the carbon significantly affects the interplay bonding process thus enhances the toluene removal. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A

    NARCIS (Netherlands)

    Andra, Syam S.; Charisiadis, Pantelis; Arora, Manish; van Vliet-Ostaptchouk, Jana V.; Makris, Konstantinos C.

    2015-01-01

    The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (Cl(x)BPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA

  19. Chloroxyanion residues in cantaloupe and tomatoes after chlorine dioxide gas sanitation

    Science.gov (United States)

    Chlorine dioxide gas is effective at cleansing fruits and vegetables of bacterial pathogens and(or) rot organisms, but few data are available on chemical residues remaining subsequent to chlorine gas treatment. Therefore, studies were conducted to quantify chlorate and perchlorate residues after tom...

  20. [Methods of disinfection of water systems in dental units by water chlorination].

    Science.gov (United States)

    Fiehn, N E; Henriksen, K

    1989-01-01

    The aim of the present study was to develop a simple disinfection method to reduce the content of bacteria in the water system of dental units to an acceptable level. The study was carried out at the Royal Dental College, Copenhagen on 250 dental units. Samples of the cooling water to the ultrasonic scalers and of the water to the water glasses were obtained from eight different units representing different parts of the school. Disinfection of the water system was carried out by addition of chlorine to the pipe water near the main water intake to the institution. The chlorination af the water was automatically regulated, and the installation was so flexible that the concentration of chlorine and the time and frequency of the chlorination could be varied. Different modes of dosage of chlorine were examined. Before chlorination the bacterial content in the water system of the units was about 10(4)-10(5) c.f.u./ml. It was found that an intermittent chlorination with 0.5-1 ppm chlorine for 10 min. every day could normally reduce the bacterial counts in the water system to about a few hundreds per ml.

  1. Methods of disinfection of the water system of dental units by water chlorination.

    Science.gov (United States)

    Fiehn, N E; Henriksen, K

    1988-12-01

    The aim of the present study was to develop a simple disinfection method for reducing the content of bacteria in the water system of dental units to an acceptable level. The study was carried out at the Royal Dental College, Copenhagen, on 250 dental units. Samples of the cooling water supplying the ultrasonic scalers and of the water supplying the water glasses were obtained from eight different units representing different parts of the school. Disinfection of the water system was carried out by addition of chlorine to the pipe water near the institution's main water intake. The chlorination of the water was automatically regulated, and the installation was so flexible that the concentration of chlorine and the time and frequency of the chlorination could be varied. Different modes of chlorine dosage were examined. Before chlorination, the bacterial content in the water system of the units was about 10(4)-10(5) cfu/mL. It was found that an intermittent chlorination with 0.5-1 ppm chlorine for 10 minutes every day could reduce the normal bacterial counts in the water system to about a few hundred per mL.

  2. The Dutch secret: how to provide safe drinking water without chlorine in the Netherlands

    NARCIS (Netherlands)

    Smeets, P.W.M.H.; Medema, G.J.; Van Dijk, J.C.

    2009-01-01

    The Netherlands is one of the few countries where chlorine is not used at all, neither for primary disinfection nor to maintain a residual disinfectant in the distribution network. The Dutch approach that allows production and distribution of drinking water without the use of chlorine while not comp

  3. Determination of rapid chlorination rate constants by a stopped-flow spectrophotometric competition kinetics method.

    Science.gov (United States)

    Song, Dean; Liu, Huijuan; Qiang, Zhimin; Qu, Jiuhui

    2014-05-15

    Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe. A kinetic equation was first derived to estimate the reaction rate constant of DPD towards chlorine under a given pH and temperature condition. Then, on that basis, an SFS competition kinetics method was proposed to determine directly the chlorination rate constants of several representative compounds including tetracycline, ammonia, and four α-amino acids. Although Cl2O is more reactive than HOCl, its contribution to the overall chlorination kinetics of the test compounds could be neglected in this study. Finally, the developed method was validated through comparing the experimentally measured chlorination rate constants of the selected compounds with those obtained or calculated from literature and analyzing with Taft's correlation as well. This study demonstrates that the SFS competition kinetics method can measure the chlorination rate constants of a test compound rapidly and accurately.

  4. Effects of operating conditions on THMs and HAAs formation during wastewater chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Sun Yingxue; Wu Qianyuan [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Hu Hongying, E-mail: hyhu@tsinghua.edu.cn [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Tian Jie [Environmental Simulation and Pollution Control State Key Joint Laboratory, Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2009-09-15

    Disinfection is the last barrier of wastewater reclamation process to protect ecosystem safety and human health. However, the chlorination process results in the formation of mutagenic/carcinogenic disinfection by-products (DBPs) deriving from the reaction of the chlorine with organic compounds in wastewater. The effects of operating conditions (chlorine dose, contact time, reaction temperature and pH value) of chlorination on the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) in biologically treated wastewater samples were investigated in this study. The results indicated that the total THMs (TTHM) and total HAAs (THAA) increased exponentially with increasing chlorine dose, but there are discrepancies between the formation rates of TTHM and THAA. The THAA reached a peak at contact time of 2 h and thereafter decreased with extended time. The formation time of THMs depends on the wastewater content of quick or slow formers. The yields of bromated HAAs (as MBAA, BCAA, and BDCAA) would decrease markedly after the contact time over 2 h during wastewater chlorination, and were favored in low pH values of 4 and high pH values of 9 under certain contact time. In addition, the formation of MBAA, BCAA, BDCAA decreased gradually as reaction temperature increased from 4 to 30 deg. C in the chlorination of wastewater containing a certain concentration of bromide. The effects of operating conditions on THMs and HAAs formation during wastewater chlorination were completely different from those of surface water disinfection.

  5. Second-order chlorine decay and trihalomethanes formation in a pilot-scale water distribution systems.

    Science.gov (United States)

    Li, Cong; Yang, Y Jeffrey; Yu, Jieze; Zhang, Tu-qiao; Mao, Xinwei; Shao, Weiyun

    2012-08-01

    It is well known that model-building of chlorine decay in real water distribution systems is difficult because chlorine decay is influenced by many factors (e.g., bulk water demand, pipe-wall demand, piping material, flow velocity, and residence time). In this paper, experiments were run to investigate the kinetic model of chlorine decay and the formation model of trihalomethanes (THMs) in pilot-scale water distribution systems. Experimental results show that the rate constants of chlorine decay, including wall decay and bulk decay, increasing with temperature. Moreover, the kinetic model of chlorine decay and the formation model of THMs describe experiment data of pilot-scale water distribution systems. The effect of different piping material on chlorine decay and THMs formation were also investigated. The rate constants of chlorine decay are ranked in order: stainless steel pipe, ductile iron pipe, and last, polyethelene pipe because wall decay is the largest in stainless steel pipe than that in other piping material. Correspondingly, the rate of THMs formation follows the order of stainless steel pipe, ductile iron pipe, and last, polyethelene pipe because of less chlorine in bulk water reacting with the trihalomethane formation potential (THMFP).

  6. [Inactivation of the chlorine-resistant bacteria isolated from the drinking water distribution system].

    Science.gov (United States)

    Chen, Yu-Qiao; Duan, Xiao-Di; Lu, Pin-Pin; Wang, Qian; Zhang, Xiao-Jian; Chen, Chao

    2012-01-01

    Inactivation experiments of seven strains of chlorine-resistant bacteria, isolated from a drinking water distribution system, were conducted with four kinds of disinfectants. All the bacteria showed high resistance to chlorine, especially for Mycobacterium mucogenicum. The CT value of 99.9% inactivation for M. mucogenicum, Sphingomonas sanguinis and Methylobacterium were 120 mg x (L x min)(-1), 7 mg x (L x min)(-1) and 4 mg x (L x min)(-1), respectively. The results of inactivation experiments showed that chlorine dioxide and potassium monopersulfate could inactive 5 lg of M. mucogenicum within 30 min, which showed significantly higher efficiency than free chlorine and monochloramine. Free chlorine was less effective because the disinfectant decayed very quickly. Chloramination needed higher concentration to meet the disinfection requirements. The verified dosage of disinfectants, which could effectively inactivate 99.9% of the highly chlorine-resistant M. mucogenicum within 1 h, were 3.0 mg/L monochloramine, 1.0 mg/L chlorine dioxide (as Cl2), and 1.0 mg/L potassium monopersulfate (as Cl2). It was suggested that the water treatment plants increase the concentration of monochloramine or apply chlorine dioxide intermittently to control the disinfectant-resistant bacteria.

  7. Enantioselective α-Chlorination of Aldehydes with Recyclable Fluorous (S)-Pyrrolidine-Thiourea Bifunctional Organocatalyst.

    Science.gov (United States)

    Wang, Liang; Cai, Chun; Curran, Dennis P; Zhang, Wei

    2010-01-01

    A novel fluorous (S)-pyrrolidine-thiourea bifunctional organocatalyst is prepared. The catalyst shows good activity and enantioselectivity for direct α-chlorination of aldehydes using N-chlorosuccinimide (NCS) as the chlorine source. It can be recovered from the reaction mixture by fluorous solid-phase extraction with excellent purity for direct reuse.

  8. A Guide for Selecting Remedies for Subsurface Releases of Chlorinated Solvents

    Science.gov (United States)

    2011-03-01

    better job of establishing objectives that effectively SECTION 3 A Guide for Selecting Remedies for Subsurface Releases of Chlorinated...create conditions that favor reductive dechlorination of chlorinated ethenes. Common electron donors include vegetable oil, molasses, lactate , and...neighborhood.  Regionally, the community is committed to a clean environment while wanting to preserve jobs .  The facility owners are committed to

  9. Sorption- and diffusion-associated isotope effects for chlorinated and non chlorinated aromatic hydrocarbons in a sediment pore water diffusion sampler

    Science.gov (United States)

    Passeport, E.; Chu, K.; Lacrampe Couloume, G.; Landis, R.; Lutz, E. J.; Mack, E. E.; West, K.; Sherwood Lollar, B.

    2013-12-01

    Compound Specific Isotope Analysis (CSIA) has gained prominence for evaluation of microbial and abiotic degradation processes governing the fate of organic contaminants in groundwater. At the sediment pore water interface, in wetland or river bottom sediments, variations in oxidation-reduction conditions can affect reaction mechanisms and hence the contaminant mass flux discharged to surface waters. Carbon isotope fractionation has been shown to be an important tool in identifying the effects of degradation and differentiating between different degradation pathways. To date, while passive diffusion samplers (commonly called 'peepers') have provided a powerful tool for high spatial resolution sampling for dissolved VOC across the sediment water interface, peepers' compatibility with CSIA has never been evaluated. The operating principle of peepers involves compound diffusion from the sediment pore water to the peeper chambers via a membrane. In this study, we evaluated the isotope effects of diffusion through, and possible adsorption to a polysulfone membrane for priority groundwater contaminants including chlorinated and non-chlorinated aromatic hydrocarbons. Chlorinated benzenes tend to accumulate in the food web and therefore represent a significant threat to water resources. This is due to their larger sorption coefficients (Koc) and higher hydrophobicity properties (logKow) compared to other commonly-studied compounds (e.g., chlorinated ethenes). Application of CSIA to BTEX and chlorinated ethenes has demonstrated that non-degradative processes (e.g., sorption, volatilization, diffusion) typically result in smaller carbon isotope fractionation compared to degradative processes that involve breaking bonds. The large sorption properties of chlorinated benzenes preclude a direct extrapolation to these compounds of existing data on sorption-associated isotope effects obtained on other compounds. To date, similar studies have not been done for chlorinated aromatics

  10. Comparative toxicities of oxygen, ozone, chlorine dioxide, and chlorine bleaching filtrates - microtox toxicities of raw and processed filtrates

    Energy Technology Data Exchange (ETDEWEB)

    Ard, T.A.; McDonough, T.J.

    1995-12-31

    It has claimed that effluents from the bleaching of kraft pulp with chlorine and its compounds have deleterious effects on the aquatic environment. It has been further suggested that bleaching without the use of chlorine or its compounds will produce innocuous effluents. To obtain information on the validity of these claims, we have conducted a laboratory study of the toxicity of filtrates from chlorine-based and nonchlorine bleaching processes. We have also examined two related issues. The first is whether any toxicants generated during bleaching are rendered harmless (by neutralization, storage, and biological treatment) before being discharged to the environment. The second related issue is whether any toxicity observed in mill effluents actually originates in the bleaching process, as opposed to being due to raw material components or compounds formed during the pulping step that precedes bleaching. Several conclusions were drawn from this study. (1) There is a background level of toxicity which originates in the oxygen stage, process steps prior to bleaching, or in the wood raw material. It is decreased by neutralization and storage, but residual toxicity may still be detected after two weeks. (2) If the sum of the first and second stage toxicities is taken as an indicator of overall toxicity, the untreated filtrates may be ranked as follows: Control (Background) > D(EO) > Z(EO) > C(EO). However, these toxicities are of no importance in regard to environmental effects because of their ephemeral nature and the likelihood of their being reduced or eliminated prior to effluent discharge. Evidence for this statement is the ease with which all except the C(EO) were detoxified by neutralization and storage. (3) After neutralization and storage for two weeks at room temperature the ranking of toxicities becomes: C(EO) > D(EO) > Z(EO) > Background. The last three are similar in magnitude.

  11. Using the nuclear activation AMS method for determining chlorine in solids at ppb-levels and below

    Science.gov (United States)

    Winkler, Stephan R.; Eigl, Rosmarie; Forstner, Oliver; Martschini, Martin; Steier, Peter; Sterba, Johannes H.; Golser, Robin

    2015-10-01

    Neutron activation analysis using decay counting of the activated element is a well-established method in elemental analysis. However, for chlorine there is a better alternative to measuring decay of the short-lived activation product chlorine-38 (t1/2 = 37.24 min) - accelerator mass spectrometry (AMS) of 36Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t1/2 = 301 ka) allow for determination of chlorine down to ppb-levels using practical sample sizes and common exposure durations. The combination of neutron activation and AMS can be employed for a few other elements (nitrogen, thorium, and uranium) as well. For bulk solid samples an advantage of the method is that lab contamination can be rendered irrelevant. The chlorine-35 in the sample is activated to chlorine-36, and surface chlorine can be removed after the irradiation. Subsequent laboratory contamination, however, will not carry a prominent chlorine-36 signature. After sample dissolution and addition of sufficient amounts of stable chlorine carrier the produced chlorine-36 and thus the original chlorine-35 of the sample can be determined using AMS. We have developed and applied the method for analysis of chlorine in steel samples. The chlorine content of steel is of interest to nuclear industry, precisely because of above mentioned high neutron capture cross section for chlorine-35, which leads to accumulation of chlorine-36 as long-term nuclear waste. The samples were irradiated at the TRIGA Mark II reactor of the Atominstitut in Vienna and the 36Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for 36Cl/Cl analysis.

  12. Screening of organic halogens and identification of chlorinated benzoic acids in carbonaceous meteorites.

    Science.gov (United States)

    Schöler, Heinz F; Nkusi, Gerard; Niedan, Volker W; Müller, German; Spitthoff, Bianca

    2005-09-01

    The occurrence of halogenated organic compounds measured as a sum parameter and the evidence of chlorinated benzoic acids in four carbonaceous meteorites (Cold Bokkeveld, Murray, Murchison and Orgueil) from four independent fall events is reported. After AOX (Adsorbable organic halogen) and EOX (Extractable organic halogen) screening to quantify organically bound halogens, chlorinated organic compounds were analyzed by gas chromatography. AOX concentrations varying from 124 to 209 microg Cl/g d.w. were observed in carbonaceous meteorites. Ion chromatographic analysis of the distribution of organically bound halogens performed on the Cold Bokkeveld meteorite revealed that chlorinated and brominated organic compounds were extractable, up to 70%, whereas only trace amounts of organofluorines could be extracted. Chlorinated benzoic acids have been identified in carbonaceous meteorite extracts. Their presence and concentrations raise the question concerning the origin of halogenated, especially chlorinated, organic compounds in primitive planetary matter.

  13. Structure and properties of Ni(110) surface coadsorbing chlorine and oxygen

    Institute of Scientific and Technical Information of China (English)

    庄叔贤; 季明荣; 吴建新; 屠兢; 方文秀; 俞爽英; Klaus Wandelt

    1996-01-01

    The coadsorption of chlorine with oxygen on Ni(110) surface has been investigated by XPS, UPS, AES and work function measurements. The chlorine preadsorption drastically inhibits the further uptake of oxygen. On the contrary, precovered oxygen has hardly any influence on the additional adsorption of chlorine due to the incorporation of precovered oxygen into the subsurface driven by the chlorine coadsorption. ARXPS measurements provide the evidence for this coadsorption model. The thermal desorption of chlorine and oxygen from the coadsorption surface is very similar to that of both individual adsorbates under the same heating conditions, but the desorption temperature of both the adsorbates apparently decreases on the coadsorption surface. The coadsorption and thermodesorption mechanisms are also discussed in detail.

  14. Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and freshwater organisms

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, C.R.; Sugam, R.; Meldrim, J.W.; Holmstrom, E.R.; Balog, G.E.

    1980-08-01

    As a part of a program at PSE and G designed to examine the feasibility of ozonation as an alternative to chlorination for control of biofouling in once-through cooling systems, the biological effects of ozonated and chlorinated thermal discharges were evaluated with estuarine and freshwater organisms. Mortality at salinities between 0.5 to 2.5 ppt with mummichog and white perch indicated greater toxicity for chlorine while the alewife, spottail shiner, rainbow trout and white perch in freshwater were more sensitive to ozone. Behavioral and physograhic results were consistent with those observed in toxicity studies. Initial cough response and avoidance concentrations of mummicog and white perch in estuarine waters were lower when exposed to chlorine than to ozone. In freshwater, blueback herring, alewife, rainbow trout, spottail shiner, banded killifish, and white perch avoided lower concentrations of ozone than chlorine.

  15. Direct chlorination process for geothermal power plant off-gas - hydrogen sulfide abatement

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5 percent hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90 percent excess chlorine gas was used. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

  16. Evidence for strong, widespread chlorine radical chemistry associated with pollution outflow from continental Asia

    Science.gov (United States)

    Baker, Angela K.; Sauvage, Carina; Thorenz, Ute R.; van Velthoven, Peter; Oram, David E.; Zahn, Andreas; Brenninkmeijer, Carl A. M.; Williams, Jonathan

    2016-11-01

    The chlorine radical is a potent atmospheric oxidant, capable of perturbing tropospheric oxidative cycles normally controlled by the hydroxyl radical. Significantly faster reaction rates allow chlorine radicals to expedite oxidation of hydrocarbons, including methane, and in polluted environments, to enhance ozone production. Here we present evidence, from the CARIBIC airborne dataset, for extensive chlorine radical chemistry associated with Asian pollution outflow, from airborne observations made over the Malaysian Peninsula in winter. This region is known for persistent convection that regularly delivers surface air to higher altitudes and serves as a major transport pathway into the stratosphere. Oxidant ratios inferred from hydrocarbon relationships show that chlorine radicals were regionally more important than hydroxyl radicals for alkane oxidation and were also important for methane and alkene oxidation (>10%). Our observations reveal pollution-related chlorine chemistry that is both widespread and recurrent, and has implications for tropospheric oxidizing capacity, stratospheric composition and ozone chemistry.

  17. Recent research activities and future subjects on stable- and radio-isotopes of chlorine in environment

    Energy Technology Data Exchange (ETDEWEB)

    Kushita, Kouhei [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-12-01

    This report reviews the recent studies on the stable- and radio-isotopes of chlorine from a viewpoint of environmental science, partly including historic references on this element. First, general properties, occurrence, and utilization of chlorine are described. Secondly, current status and research works on chlorine-compounds, which attract special attention in recent years as environmentally hazardous materials, are reported. Thirdly, research works on stable chlorine isotopes, {sup 35}Cl and {sup 37}Cl, are described with a focus laid on the newly-developed techniques; isotopic ratio mass spectrometry (IRMS) and thermal ionization mass spectrometry (TIMS). Fourthly, recent research works on chlorine radioisotopes, {sup 36}Cl etc., are described, focusing on the development of accelerator mass spectrometry (AMS) and its application to geochemistry and others. Finally, taking account of the above-mentioned recent works on Cl isotopes, possible future research subjects are discussed. (author)

  18. Electrochemical cell design for the impedance studies of chlorine evolution at DSA anodes

    Science.gov (United States)

    Silva, J. F.; Dias, A. C.; Araújo, P.; Brett, C. M. A.; Mendes, A.

    2016-08-01

    A new electrochemical cell design suitable for the electrochemical impedance spectroscopy (EIS) studies of chlorine evolution on Dimensionally Stable Anodes (DSA®) has been developed. Despite being considered a powerful tool, EIS has rarely been used to study the kinetics of chlorine evolution at DSA anodes. Cell designs in the open literature are unsuitable for the EIS analysis at high DSA anode current densities for chlorine evolution because they allow gas accumulation at the electrode surface. Using the new cell, the impedance spectra of the DSA anode during chlorine evolution at high sodium chloride concentration (5 mol dm-3 NaCl) and high current densities (up to 140 mA cm-2) were recorded. Additionally, polarization curves and voltammograms were obtained showing little or no noise. EIS and polarization curves evidence the role of the adsorption step in the chlorine evolution reaction, compatible with the Volmer-Heyrovsky and Volmer-Tafel mechanisms.

  19. Electrochemical cell design for the impedance studies of chlorine evolution at DSA(®) anodes.

    Science.gov (United States)

    Silva, J F; Dias, A C; Araújo, P; Brett, C M A; Mendes, A

    2016-08-01

    A new electrochemical cell design suitable for the electrochemical impedance spectroscopy (EIS) studies of chlorine evolution on Dimensionally Stable Anodes (DSA(®)) has been developed. Despite being considered a powerful tool, EIS has rarely been used to study the kinetics of chlorine evolution at DSA anodes. Cell designs in the open literature are unsuitable for the EIS analysis at high DSA anode current densities for chlorine evolution because they allow gas accumulation at the electrode surface. Using the new cell, the impedance spectra of the DSA anode during chlorine evolution at high sodium chloride concentration (5 mol dm(-3) NaCl) and high current densities (up to 140 mA cm(-2)) were recorded. Additionally, polarization curves and voltammograms were obtained showing little or no noise. EIS and polarization curves evidence the role of the adsorption step in the chlorine evolution reaction, compatible with the Volmer-Heyrovsky and Volmer-Tafel mechanisms.

  20. Field-usable portable analyzer for chlorinated organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Buttner, W.J.; Penrose, W.R.; Stetter, J.R. [Transducer Research, Inc., Naperville, IL (United States)

    1995-10-01

    Transducer Research, Inc. (TRI) has been working with the DOE Morgantown Energy Technology Center to develop a new chemical monitor based on a unique sensor which responds selectively to vapors of chlorinated solvents. We are also developing field applications for the monitor in actual DOE cleanup operations. During the initial phase, prototype instruments were built and field tested. Because of the high degree of selectivity that is obtained, no response was observed with common hydrocarbon organic compounds such as BTX (benzene, toluene, xylene) or POLs (petroleum, oil, lubricants), and in fact, no non-halogen-containing chemical has been identified which induces a measurable response. By the end of the Phase I effort, a finished instrument system was developed and test marketed. This instrument, called the RCL MONITOR, was designed to analyze individual samples or monitor an area with automated repetitive analyses. Vapor levels between 0 and 500 ppm can be determined in 90 s with a lower detection limit of 0.2 ppm using the handportable instrument. In addition to the development of the RCL MONITOR, advanced sampler systems are being developed to: (1) extend the dynamic range of the instrument through autodilution of the vapor and (2) allow chemical analyses to be performed on aqueous samples. When interfaced to the samplers, the RCL MONITOR is capable of measuring chlorinated solvent contamination in the vapor phase up to 5000 ppm and in water and other condensed media from 10 to over 10,000 ppb(wt)--without hydrocarbon and other organic interferences.

  1. Atmospheric chlorinated polycyclic aromatic hydrocarbons in East Asia.

    Science.gov (United States)

    Kakimoto, Kensaku; Nagayoshi, Haruna; Konishi, Yoshimasa; Kajimura, Keiji; Ohura, Takeshi; Hayakawa, Kazuichi; Toriba, Akira

    2014-09-01

    This study estimates atmospheric concentrations of chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and polycyclic aromatic hydrocarbons (PAHs) in East Asia using a Gas Chromatograph with High Resolution Mass Spectrometer (GC-HRMS). ClPAHs are ubiquitously generated from PAHs through substitution, and some ClPAHs show higher aryl hydrocarbon receptor (AhR)-mediated activities than their parent PAHs. Atmospheric particles were collected using a high-volume air sampler equipped with a quartz-fiber filter. We determined the ClPAH concentrations of atmospheric particles collected in Japan (Sapporo, Sagamihara, Kanazawa, and Kitakyushu), Korea (Busan), and China (Beijing). The concentrations of ClPAHs were highest in the winter Beijing sample, where the total mean concentration was approximately 15-70 times higher than in the winter samples from Japan and Korea. The concentrations of Σ19ClPAHs and Σ9PAHs were significantly correlated in the Kanazawa and the Busan samples. This indicates that within those cities ClPAHs and PAHs share the same origin, implying direct chlorination of parent PAHs. Toxic equivalent concentrations (TEQs) of the total ClPAHs and PAHs were lowest in Kanazawa in the summer, reaching 1.18 and 2610fg-TEQm(-3) respectively, and highest in Beijing in the winter, reaching 627 and 4240000fg-TEQm(-3) respectively.

  2. Kinetics and mechanism of dimethoate chlorination during drinking water treatment.

    Science.gov (United States)

    Tian, Fang; Liu, Wenjun; Guo, Guang; Qiang, Zhimin; Zhang, Can

    2014-05-01

    Dimethoate (DMT), a commonly used organophosphorus pesticide, is of great concern because of its toxicity and potentially harmful effects on water sources. The elimination of DMT as well as the toxicity and persistence of the byproducts formed during DMT degradation is most important for the safety of drinking water. This study first determined the reaction kinetics of DMT with free chlorine (FC) under typical water treatment conditions. The reaction between DMT and FC proceeded rapidly, exhibiting first-order with respect to each reactant. The degradation of DMT by FC was highly pH dependent, and the pseudo-first-order rate constant decreased obviously from 0.13 to 0.02 s(-1) with an increase in pH from 7.0 to 8.3. Bromide ion accelerated the reaction by acting as a catalyst, and the accelerated reaction rate was linearly proportional to the bromide concentration. As a ubiquitous component in natural waters, humic acid also increased the reaction rate. However, the presence of ammonium inhibited the degradation of DMT due to its rapid converting FC to chloramines. Omethoate (OMT) was identified as an important byproduct of DMT chlorination, but only accounted for ca. 28% of the DMT degraded; and other two organic byproducts were also identified. The acute toxicity of DMT solution increased after treatment with FC due to the formation of more toxic byproducts (e.g. OMT).

  3. Accidental release of chlorine and its impact on urban areas

    Energy Technology Data Exchange (ETDEWEB)

    El-Sheikh, H.A.; Badr, O.A.; El Kadi, H.M.; Hamoda, M.F. [United Arab Emirates Univ., Abu Dhabi (United Arab Emirates). Faculty of Engineering

    1995-12-31

    Among the possible scenarios of accidental releases of chlorine from high pressure cylinders, this paper considers a typical one for the analysis. The calculated transient mass flow rate of chlorine released from a one-tonne cylinder showed that such an accident takes about 10 minutes to evacuate the cylinder. However, the toxic effect in the surrounding atmosphere continues for a longer period (about 20 minutes). The size and location of the toxic cloud at ground level were predicted as functions of time using an EPA-based dispersion model. The results showed a growth of the toxic cloud for some time beyond which it started to decay. For the typical scenario considered in this study, the most dangerous situation generated a toxic cloud with dimensions of 4000 m and 600 m in the downwind and crosswind directions, respectively. A study of the effects of some meteorological parameters on the size and location of the toxic cloud at ground level was also conducted. In general, it was observed that enhancing atmospheric mixing produced larger toxic zones during the early stages of the release and caused an opposite effect during the later ones. This dynamic data was linked to a GIS environment and the time variant was represented using an animation technique for Al-Ain City, United Arab Emirates. Data base information related to physical urban characteristics and population was immediately obtained for the affected areas.

  4. Sporicidal/bactericidal textiles via the chlorination of silk.

    Science.gov (United States)

    Dickerson, Matthew B; Lyon, Wanda; Gruner, William E; Mirau, Peter A; Slocik, Joseph M; Naik, Rajesh R

    2012-03-01

    Bacterial spores, such as those of the Bacillus genus, are extremely resilient, being able to germinate into metabolically active cells after withstanding harsh environmental conditions or aggressive chemical treatments. The toughness of the bacterial spore in combination with the use of spores, such as those of Bacillus anthracis, as a biological warfare agent necessitates the development of new antimicrobial textiles. In this work, a route to the production of fabrics that kill bacterial spores and cells within minutes of exposure is described. Utilizing this facile process, unmodified silk cloth is reacted with a diluted bleach solution, rinsed with water, and dried. The chlorination of silk was explored under basic (pH 11) and slightly acidic (pH 5) conditions. Chloramine-silk textiles prepared in acidified bleach solutions were found to have superior breaking strength and higher oxidative Cl contents than those prepared under caustic conditions. Silk cloth chlorinated for ≥1 h at pH 5 was determined to induce >99.99996% reduction in the colony forming units of Escherichia coli, as well as Bacillus thuringiensis Al Hakam (B. anthracis simulant) spores and cells within 10 min of contact. The processing conditions presented for silk fabric in this study are highly expeditionary, allowing for the on-site production of protein-based antimicrobial materials from a variety of agriculturally produced feed-stocks.

  5. Evidence for heterogeneous chlorine activation in the tropical UTLS

    Science.gov (United States)

    von Hobe, M.; Grooß, J.-U.; Günther, G.; Konopka, P.; Gensch, I.; Krämer, M.; Spelten, N.; Afchine, A.; Schiller, C.; Ulanovsky, A.; Sitnikov, N.; Shur, G.; Yushkov, V.; Ravegnani, F.; Cairo, F.; Roiger, A.; Voigt, C.; Schlager, H.; Weigel, R.; Frey, W.; Borrmann, S.; Müller, R.; Stroh, F.

    2011-01-01

    Airborne in-situ observations of ClO in the tropics were made during the TROCCINOX (Aracatuba, Brazil, February 2005) and SCOUT-O3 (Darwin, Australia, November/December 2005) field campaigns. While during most flights significant amounts of ClO (≈10-20 parts per trillion, ppt) were present only in aged stratospheric air, instances of enhanced ClO mixing ratios of up to 40 ppt - significantly exceeding those expected from gas phase chemistry - were observed in air masses of a more tropospheric character. Most of these observations are associated with low temperatures or with the presence of cirrus clouds (often both), suggesting that cirrus ice particles and/or liquid aerosol at low temperatures may promote significant heterogeneous chlorine activation in the tropical upper troposphere lower stratosphere (UTLS). In two case studies, particularly high levels of ClO observed were reproduced by chemistry simulations only under the assumption that significant denoxification had occurred in the observed air. However, to reproduce the ClO observations in these simulations, O3 mixing ratios higher than observed had to be assumed, and at least for one of these flights, a significant denoxification is in contrast to the observed NO levels, suggesting that the coupling of chlorine and nitrogen compounds in the tropical UTLS may not be completely understood.

  6. Chlorine isotope separation using an hydrous zirconium dioxide exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, K.G.; Baier, K.; Wibmer, G.

    1980-05-01

    Hydrous zirconium dioxide is used in column experiments for separating the halide ions as well as for isotope fractionation of chlorine. The preparation of the zirconium dioxide particles is carried out by homogeneous hydrolysis of a zirconyl chloride solution using hexamethylenetetramine. The separation order of the halides is I/sup -/, Br/sup -/ and Cl/sup -/ in contrast to the inverse separation order using a strongly basic anion exchange resin. In chlorine isotope separation experiments an enrichment of /sup 35/Cl/sup -/ is found in the first fractions, whereas the last fractions show a significant enrichment of /sup 37/Cl/sup -/. This also indicates an inversion of the isotope separation compared with a strongly basic anion exchange resin. A dependence of the isotope fractionation on the concentration of the NaNO/sub 3/ solution used as eluant is found. With increasing concentration the isotope fractionation decreases. Using a 0.5 M NaNO/sub 3/ solution the elementary separation effect was calculated epsilon done on different tantalum parts to determine the amount of dissolved hydrogen.

  7. Chlorine isotope separation using an hydrous zirconium dioxide exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, K.G.; Baier, K.; Wibmer, G.

    1980-05-01

    Hydrous zirconium dioxide is used in column experiments for separating the halide ions as well as for isotope fractionation of chlorine. The preparation of the zirconium dioxide particles is carried out by homogeneous hydrolysis of a zirconyl chloride solution using hexamethylenetetramine. The separation order of the halides is I/sup -/, Br/sup -/ and Cl/sup -/ in contrast to the inverse separation order using a strongly basic anion exchange resin. In chlorine isotope separation experiments an enrichment of /sup 35/Cl/sup -/ is found in the first fractions, whereas the last fractions show a significant enrichment of /sup 37/Cl/sup -/. This also indicates an inversion of the isotope separation compared with a strongly basic anion exchange resin. A dependence of the isotope fractionation on the concentration of the NaNO/sub 3/ solution used as eluant is found. With increasing concentration the isotope fractionation decreases. Using a 0.5 M NaNO/sub 3/ solution the elementary separation effect was calculated epsilon = 6,1 x 10/sup -4/. This is one of the highest isotope fractionations known in a chloride isotope exchange system. The results show that the electrolyte behaviour of isotopes is comparable to that of a series of homologous elements.

  8. Oxidation of phenol and hydroquinone by chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Wajon, J.E.; Rosenblatt, D.H.; Burrows, E.P.

    1982-07-01

    Rates of reaction of chlorine dioxide with phenol and with hydroquinone were determined with a stopped-flow spectrophotometer in the pH range 4-8. Second-order rate constants increase with increasing pH, consistent with a mechanism in which both the free phenol and the more reactive phenoxide anion react with ClO/sub 2/. Removal of an electron from the substrate by ClO/sub 2/ to form a phenoxyl radical and ClO/sub 2//sup -/ ion is the rate-determining step. Subsequently, in the case of hydroquinone, ClO/sub 2/ removes another electron from the radical, forming p-benzoquinone and another ClO/sub 2//sup -/ ion. In the case of phenol, ClO/sub 2/ adds to the phenoxyl radical para to the oxygen, and p-benzoquinone is formed with concomitant release of HOCl. The mechanism for phenol reaction accounts for (i) the immediate formation of p-benzoquinone without apparent intermediacy of hydroquinone, (ii) the chlorination observed in solutions containing excess phenol, and (iii) the production of only 0.5 mol of ClO/sub 2//sup -//mol of ClO/sub 2/ consumed.

  9. Immobilization of chlorine dioxide modified cells for uranium absorption.

    Science.gov (United States)

    He, Shengbin; Ruan, Binbiao; Zheng, Yueping; Zhou, Xiaobin; Xu, Xiaoping

    2014-11-01

    There has been a trend towards the use of microorganisms to recover metals from industrial wastewater, for which various methods have been reported to be used to improve microorganism adsorption characteristics such as absorption capacity, tolerance and reusability. In present study, chlorine dioxide(ClO2), a high-efficiency, low toxicity and environment-benign disinfectant, was first reported to be used for microorganism surface modification. The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. FTIR analysis indicated that several cell surface groups are involved in the uranium adsorption and cell surface modification. The modified cells were further immobilized on a carboxymethylcellulose(CMC) matrix to improve their reusability. The cell-immobilized adsorbent could be employed either in a high concentration system to move vast UO2(2+) ions or in a low concentration system to purify UO2(2+) contaminated water thoroughly, and could be repeatedly used in multiple adsorption-desorption cycles with about 90% adsorption capacity maintained after seven cycles.

  10. Potential biodefense model applications for portable chlorine dioxide gas production.

    Science.gov (United States)

    Stubblefield, Jeannie M; Newsome, Anthony L

    2015-01-01

    Development of decontamination methods and strategies to address potential infectious disease outbreaks and bioterrorism events are pertinent to this nation's biodefense strategies and general biosecurity. Chlorine dioxide (ClO2) gas has a history of use as a decontamination agent in response to an act of bioterrorism. However, the more widespread use of ClO2 gas to meet current and unforeseen decontamination needs has been hampered because the gas is too unstable for shipment and must be prepared at the application site. Newer technology allows for easy, onsite gas generation without the need for dedicated equipment, electricity, water, or personnel with advanced training. In a laboratory model system, 2 unique applications (personal protective equipment [PPE] and animal skin) were investigated in the context of potential development of decontamination protocols. Such protocols could serve to reduce human exposure to bacteria in a decontamination response effort. Chlorine dioxide gas was capable of reducing (2-7 logs of vegetative and spore-forming bacteria), and in some instances eliminating, culturable bacteria from difficult to clean areas on PPE facepieces. The gas was effective in eliminating naturally occurring bacteria on animal skin and also on skin inoculated with Bacillus spores. The culturable bacteria, including Bacillus spores, were eliminated in a time- and dose-dependent manner. Results of these studies suggested portable, easily used ClO2 gas generation systems have excellent potential for protocol development to contribute to biodefense strategies and decontamination responses to infectious disease outbreaks or other biothreat events.

  11. Chlorine dioxide reaction with selected amino acids in water

    Energy Technology Data Exchange (ETDEWEB)

    Navalon, Sergio; Alvaro, Mercedes [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain); Garcia, Hermenegildo, E-mail: hgarcia@qim.upv.es [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain)

    2009-05-30

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO{sub 2} with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO{sub 2} were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO{sub 2} creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO{sub 2} with ubiquitous amino acids present in natural waters.

  12. Chlorine doped graphene quantum dots: Preparation, properties, and photovoltaic detectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jianhong; Xiang, Jinzhong, E-mail: jzhxiang@ynu.edu.cn [School of Physical Science and Technology, Yunnan University, Kunming 650091 (China); Tang, Libin, E-mail: scitang@163.com; Ji, Rongbin, E-mail: jirongbin@gmail.com; Yuan, Jun; Zhao, Jun; Yu, Ruiyun; Tai, Yunjian; Song, Liyuan [Kunming Institute of Physics, Kunming 650223 (China)

    2014-09-15

    Graphene quantum dots (GQDs) are becoming one of the hottest advanced functional materials because of the opening of the bandgap due to quantum confinement effect, which shows unique optical and electrical properties. The chlorine doped GQDs (Cl-GQDs) have been fabricated by chemical exfoliation of HCl treated carbon fibers (CFs), which were prepared from degreasing cotton through an annealing process at 1000 °C for 30 min. Raman study shows that both G and 2D peaks of GQDs may be redshifted (softened) by chlorine doping, leading to an n-type doping. The first vertical (Cl)-GQDs based photovoltaic detectors have been demonstrated, both the light absorbing and electron-accepting roles for (Cl)-GQDs in photodetection have been found, resulting in an exceptionally big ratio of photocurrent to dark current as high as ∼10{sup 5} at room temperature using a 405 nm laser irradiation under the reverse bias voltage. The study expands the application of (Cl)-GQDs to the important optoelectronic detection devices.

  13. Phytotoxicity of chlorinated benzenes to Typha angustifolia and Phragmites communis.

    Science.gov (United States)

    Ma, Xingmao; Havelka, Megan M

    2009-02-01

    Healthy growth of plants is a prerequisite for successful application of phytoremediation technologies. Typha angustifolia and Phragmites communis are common wetland plants and have shown potential for phytoremediation of hexachlorobenzene (HCB). However, the lack of phytotoxicity data impedes their application in field sites. This study investigated the phytotoxicity of HCB, and its two metabolites: 1,3,5-trichlorobenzene (1,3,5-TCB) and 1,4-dichlorobenzene (1,4-DCB) to Typha and the phytotoxicity of 1,3,5-TCB to Phragmites. The phytotoxicity of 1,3,5-TCB is species-dependent, with Typha demonstrating significantly higher tolerance than Phragmites. The concentration of 1,3,5-TCB causing zero growth of Phragmites was determined to be 1575 mg TCB/kg dry sediment. The concentration has to be doubled to completely inhibit the growth of Typha. Adverse effects of chlorinated benzenes in sediments on Typha increased with decreasing chlorine atoms. The concentrations causing zero growth of Typha are 5765 mg HCB/kg dry soil, 3157 mg 1,3,5-TCB/kg dry soil, and 1325 mg 1,4-DCB/kg dry soil. The higher toxicity of 1,4-DCB than 1,3,5-TCB and HCB in sediment was ascribed to its higher availability and easiness to be taken up by plants. The conclusion was supported by both growth rate calculations and plant height measurements. (c) 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.

  14. Thermal electron attachment to chlorinated alkenes in the gas phase

    Science.gov (United States)

    Wnorowski, K.; Wnorowska, J.; Michalczuk, B.; Jówko, A.; Barszczewska, W.

    2017-01-01

    This paper reports the measurements of the rate coefficients and the activation energies of the electron capture processes with various chlorinated alkenes. The electron attachment processes in the mixtures of chlorinated alkenes with carbon dioxide have been investigated using a Pulsed Townsend technique. This study has been performed in the temperature range (298-378) K. The obtained rate coefficients more or less depended on temperature in accordance to Arrhenius equation. The activation energies (Ea's) were determined from the fit to the experimental data points with function ln(k) = ln(A) - Ea/kBT. The rate coefficients at 298 K were equal to 1.0 × 10-10 cm3 s-1, 2.2 × 10-11 cm3 s-1, 1.6 × 10-9 cm3 s-1, 4.4 × 10-8 cm3 s-1, 2.9 × 10-12 cm3 s-1 and 7.3 × 10-12 cm3 s-1 and activation energies were: 0.27 eV, 0.26 eV, 0.25 eV, 0.21 eV, 0.55 eV and 0.42 eV, for trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, 2-chloropropene, 3-chloropropene respectively.

  15. Evidence for heterogeneous chlorine activation in the tropical UTLS

    Directory of Open Access Journals (Sweden)

    M. von Hobe

    2011-01-01

    Full Text Available Airborne in-situ observations of ClO in the tropics were made during the TROCCINOX (Aracatuba, Brazil, February 2005 and SCOUT-O3 (Darwin, Australia, November/December 2005 field campaigns. While during most flights significant amounts of ClO (≈10–20 parts per trillion, ppt were present only in aged stratospheric air, instances of enhanced ClO mixing ratios of up to 40 ppt – significantly exceeding those expected from gas phase chemistry – were observed in air masses of a more tropospheric character. Most of these observations are associated with low temperatures or with the presence of cirrus clouds (often both, suggesting that cirrus ice particles and/or liquid aerosol at low temperatures may promote significant heterogeneous chlorine activation in the tropical upper troposphere lower stratosphere (UTLS. In two case studies, particularly high levels of ClO observed were reproduced by chemistry simulations only under the assumption that significant denoxification had occurred in the observed air. However, to reproduce the ClO observations in these simulations, O3 mixing ratios higher than observed had to be assumed, and at least for one of these flights, a significant denoxification is in contrast to the observed NO levels, suggesting that the coupling of chlorine and nitrogen compounds in the tropical UTLS may not be completely understood.

  16. Evidence for heterogeneous chlorine activation in the tropical UTLS

    Directory of Open Access Journals (Sweden)

    M. von Hobe

    2010-07-01

    Full Text Available Airborne in-situ observations of ClO in the tropics were made during the TROCCINOX (Aracatuba, Brasil, February 2005 and SCOUT-O3 (Darwin, Australia, November/December 2005 field campaigns. While during most flights significant amounts of ClO (≈10–20 parts per trillion, ppt were present only in aged stratospheric air, instances of enhanced ClO mixing ratios of up to 40 ppt – significantly exceeding those expected from gas phase chemistry – were observed in air masses of a more tropospheric character. Most of these observations concur with low temperatures or with the presence of cirrus clouds (often both, suggesting that cirrus ice particles and/or liquid aerosol at low temperatures may promote significant heterogeneous chlorine activation in the tropical upper troposphere lower stratosphere (UTLS. In two case studies, particularly high levels of ClO observed were reproduced by chemistry simulations only under the assumption that significant denoxification had occurred in the observed air. At least for one of these flights, a significant denoxification is in contrast to the observed NO levels suggesting that the coupling of chlorine and nitrogen compounds in the tropical UTLS may not be completely understood.

  17. Characterization of pharmaceuticals and personal care products as N-nitrosodimethylamine precursors during disinfection processes using free chlorine and chlorine dioxide.

    Science.gov (United States)

    Zhang, Ai; Li, Yongmei; Song, Yun; Lv, Juan; Yang, Juan

    2014-07-15

    The worldwide detection of pharmaceuticals and personal care products (PPCPs) in aquatic environment and drinking water has caused wide concern in recent years. The possibility for concurrent formation of N-nitrosodimethylamine (NDMA) during disinfection has become another significant concern for water quality. This study demonstrates that a group of PPCPs containing amine groups can serve as NDMA precursors during free chlorine or chlorine dioxide (ClO2) chlorination processes. Selected PPCPs after screening by NDMA yield were further investigated for NDMA formation conditions. High disinfectant dose and initial PPCP concentration resulted in relatively high NDMA formation potential. Linear kinetic models were developed for NDMA formation during chlorination of selected PPCPs. Although the PPCP precursors were removed significantly during chlorination, they were not completely mineralized based on the total organic carbon (TOC) loss. The existence of another possible pathway for direct formation of NDMA from tertiary amine during chlorination was indicated, in which dimethylamine (DMA) was not involved. It is recommended to control the initial PPCP concentrations prior to disinfection and to shorten the contact time to reduce the NDMA formation. ClO2 is suggested to be a proper disinfectant in order to reduce the NDMA formation.

  18. Phase transformations of a talc ore under heated chlorine atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, P., E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Ruiz, M. del C. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); González, J. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza (Argentina)

    2013-02-20

    Highlights: ► We studied the effect of Cl{sub 2} on minerals present in a talc of ultramafic origin. ► Isothermal and non-isothermal assays were performed in N{sub 2} and Cl{sub 2}–N{sub 2} atmospheres. ► The reagents and the products were analyzed by DTA, XRD, SEM, and EPMA. ► The chlorination produced protoenstatite at 800 °C. ► Calcination of a talc ore in Cl{sub 2} produces more enstatite than thermal treatment in N{sub 2}. - Abstract: The effect of Cl{sub 2} on the phase transformations of the minerals present in a talc (Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}) unpurified with clinochlore (Mg{sub 5}Al{sub 2}Si{sub 3}O{sub 10}(OH){sub 8}), magnesite (MgCO{sub 3}), dolomite (MgCa(CO{sub 3}){sub 2}), hematite (Fe{sub 2}O{sub 3}) and pyrite (FeS{sub 2}) was studied with the purpose of deferricating the mineral and obtaining protoenstatite (MgSiO{sub 3}), which is the basic component of steatite ceramics. Isothermal and non-isothermal assays in N{sub 2} and Cl{sub 2}–N{sub 2} atmospheres were performed using a thermogravimetric device at temperatures between 600 and 980 °C. The reagents and the products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Results obtained showed that the following phenomena were produced in Cl{sub 2}: (a) The transformation of vitreous silica (SiO{sub 2}), from the chlorination reaction of talc, into enstatite (MgSiO{sub 3}) started at about 700 °C, being dolomite the mineral that favored this reaction. At 800 °C, more enstatite was formed as a result of the reaction between vitreous silica not transformed, MgCl{sub 2} and O{sub 2} derived from the chlorination of dolomite and magnesite; then, polymorphic transformation of enstatite into protoenstatite was produced. (b) At about 950 °C, CaCl{sub 2} produced as a result of dolomite chlorination led to the destruction of the protoenstatite

  19. Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

    Directory of Open Access Journals (Sweden)

    Xiaolu Liu

    Full Text Available Assimilable organic carbon (AOC is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM. The initial AOC concentration was 168 μg.L(-1 in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5 cells.mL(-1 to 2.6 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.6 mg.L(-1 to 4.8 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.3 mg.L(-1 due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

  20. Transformation pathways and acute toxicity variation of 4-hydroxyl benzophenone in chlorination disinfection process.

    Science.gov (United States)

    Liu, Wei; Wei, Dongbin; Liu, Qi; Du, Yuguo

    2016-07-01

    Benzophenones compounds (BPs) are widely used as UV filters, and have been frequently found in multiple environmental matrices. The residual of BPs in water would cause potential threats on ecological safety and human health. Chlorination disinfection is necessary in water treatment process, in which many chemicals remained in water would react with disinfectant chlorine and form toxic by-products. By using ultra performance liquid phase chromatography quadrupole time of flight mass spectrometer (UPLC-QTOF-MS), nuclear magnetic resonance (NMR), the transformation of 4-hydroxyl benezophenone (4HB) with free available chlorine (FAC) was characterized. Eight major products were detected and seven of them were identified. Transformation pathways of 4HB under acid, neutral, and alkaline conditions were proposed respectively. The transformation mechanisms involved electrophilic chlorine substitution of 4HB, Baeyer-Villiger oxidation of ketones, hydrolysis of esters and oxidative breakage of benzene ring. The orthogonal experiments of pH and dosages of disinfectant chlorine were conducted. The results suggested that pH conditions determined the occurrence of reaction types, and the dosages of disinfectant chlorine affected the extent of reactions. Photobacterium assay demonstrated that acute toxicity had significant increase after chlorination disinfection of 4HB. It was proved that 3,5-dichloro-4HB, one of the major transformation products, was responsible for the increasing acute toxicity after chlorination. It is notable that, 4HB at low level in real ambient water matrices could be transformed during simulated chlorination disinfection practice. Especially, two major products 3-chloro-4HB and 3,5-dichloro-4HB were detected out, implying the potential ecological risk after chlorination disinfection of 4HB.

  1. Evaluation of the infectivity, gene and antigenicity persistence of rotaviruses by free chlorine disinfection

    Institute of Scientific and Technical Information of China (English)

    Dan Li; April Z.Gu; Siyu Zeng; Wan Yang; Miao He; Hanchang Shi

    2011-01-01

    The effects of free chlorine disinfection of tap water and wastewater effluents on the infectivity,gene integrity and surface antigens of rotaviruses were evaluated by a bench-scale chlorine disinfection experiments.Plaque assays,integrated cell culture-quantitative RTPCR (ICC-RT-qPCR),RT-qPCR,and enzyme-linked immunosorbent assays (ELISA),respectively,were used to assess the influence of the disinfectant on virus infectivity as well as genetic and antigenic integrity of simian rotavirus SA11 as a surrogate for human rotaviruses.The ICC-RT-qPCR was able to detect rotaviruses survival from chlorine disinfection at chlorine dose up to 20 mg/L (60 min contact),which suggested a required chlorine dose of 5 folds (from 1 to 5 mg/L) higher than that indicated by the plaque assay to achieve 1.8 log10 reductions in tap water with 60 min exposing.The VP7 gene was more resistant than the infectivity and existed at chlorine dose up to 20 mg/L (60 min contact),while the antigencity was undetectable with chlorine dose more than 5 mg/L (60 ain contact).The water quality also impacted the inactivation efficiencies,and rotaviruses have a relatively higher resistant in secondary effluents than in the tap water under the same chlorine disinfection treatments.This study indicated that rotaviruses have a higher infectivity,gene and antigencity resistance to chlorine than that previously indicated by plaque assay only,which seemed to underestimate the resistance of rotaviruses to chlorine and the risk of rotaviruses in environments.Present results also suggested that re-evaluation of resistance of other waterborne viruses after disinfections by more sensitive infectivity detection method (such as ICC-RT-qPCR) may be necessary,to determine the adequate disinfectant doses required for the inactivation of waterborne viruses.

  2. Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

    Science.gov (United States)

    Liu, Xiaolu; Wang, Jingqi; Liu, Tingting; Kong, Weiwen; He, Xiaoqing; Jin, Yi; Zhang, Bolin

    2015-01-01

    Assimilable organic carbon (AOC) is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM). The initial AOC concentration was 168 μg.L(-1) in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5) cells.mL(-1) to 2.6 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.6 mg.L(-1) to 4.8 × 10(4) cells.mL(-1) at an initial free chlorine dose of 0.3 mg.L(-1) due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

  3. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    Energy Technology Data Exchange (ETDEWEB)

    Vacchi, Francine Inforcato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil); Ormond, Alexandra B.; Freeman, Harold S. [Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Zocolo, Guilherme Juliao; Zanoni, Maria Valnice Boldrin [Departamento de Quimica Analitica, Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Quimica de Araraquara, Araraquara, SP 14801-970 (Brazil); Umbuzeiro, Gisela, E-mail: giselau@ft.unicamp.br [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil)

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: Black-Right-Pointing-Pointer Aqueous solutions of Disperse Red 1 were treated with chlorine. Black-Right-Pointing-Pointer The chlorination products of Disperse Red 1 were identified using LC-ESI-MS/MS. Black-Right-Pointing-Pointer Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. Black-Right-Pointing-Pointer The chlorinated dye was more mutagenic

  4. Evaluation of chlorine dioxide gas treatment to inactivate Salmonella enterica on mungbean sprouts.

    Science.gov (United States)

    Prodduk, Vara; Annous, Bassam A; Liu, Linshu; Yam, Kit L

    2014-11-01

    Although freshly sprouted beans and grains are considered to be a source of nutrients, they have been associated with foodborne outbreaks. Sprouts provide good matrices for microbial localization and growth due to optimal conditions of temperature and humidity while sprouting. Also, the lack of a kill step postsprouting is a major safety concern. The objective of this work was to evaluate the effectiveness of chlorine dioxide gas treatment to reduce Salmonella on artificially inoculated mungbean sprouts. The effectiveness of gaseous chlorine dioxide (0.5 mg/liter of air) with or without tumbling (mechanical mixing) was compared with an aqueous chlorine (200 ppm) wash treatment. Tumbling the inoculated sprouts during the chlorine dioxide gas application for 15, 30, and 60 min reduced Salmonella populations by 3.0, 4.0, and 5.5 log CFU/g, respectively, as compared with 3.0, 3.0, and 4.0 log CFU/g reductions obtained without tumbling, respectively. A 2.0 log CFU/g reduction in Salmonella was achieved with an aqueous chlorine wash. The difference in microbial reduction between chlorine dioxide gas versus aqueous chlorine wash points to the important role of surface topography, pore structure, bacterial attachment, and/or biofilm formation on sprouts. These data suggested that chlorine dioxide gas was capable of penetrating and inactivating cells that are attached to inaccessible sites and/or are within biofilms on the sprout surface as compared with an aqueous chlorine wash. Consequently, scanning electron microscopy imaging indicated that chlorine dioxide gas treatment was capable of penetrating and inactivating cells attached to inaccessible sites and within biofilms on the sprout surfaces.

  5. Degradation characteristics of metoprolol during UV/chlorination reaction and a factorial design optimization.

    Science.gov (United States)

    Nam, Seung-Woo; Yoon, Yeomin; Choi, Dae-Jin; Zoh, Kyung-Duk

    2015-03-21

    Metoprolol (MTP), a hypertension depressor, has been increasingly detected even after conventional water treatment processes. In this study, the removal of MTP was compared using chlorination (Cl2), UV-C photolysis, and UV/chlorination (Cl2/UV) reactions. The results showed that the UV/chlorination reaction was most effective for MTP removal. MTP removal during UV/chlorination reaction was optimized under various conditions of UV intensity (1.1-4.4 mW/cm(2)), chlorine dose (1-5 mg/L as Cl2), pH (2-9), and dissolved organic matter (DOM, 1-4 mgC/L) using a two-level factorial design with 16 experimental combinations of the four factors. Among the factors examined, DOM scavenging by OH radicals was the most dominant in terms of MTP removal during UV/chlorination reaction. The established model fit well with the experimental results using to various water samples including surface waters, filtered and tap water samples. The optimized conditions (UV intensity=4.4 mW/cm(2), [Cl2]=5 mg/L, pH 7, and [DOM]=0.8-1.1 mgC/L) of the model removed more than 78.9% of MTP for filtered water samples during UV/chlorination reaction. Using LC-MS/MS, five byproducts of MTP (molecular weight: 171, 211, 309, 313, and 341, respectively) were identified during UV/chlorination reaction. Based on this information, the MTP transformation mechanism during UV/chlorination was suggested. Our results imply that applying UV/chlorination process after filtration stage in the water treatment plant (WTP) would be the most appropriate for effective removal of MTP.

  6. Inhibition of chlorine-induced pulmonary inflammation and edema by mometasone and budesonide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jing; Mo, Yiqun; Schlueter, Connie F.; Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu

    2013-10-15

    Chlorine gas is a widely used industrial compound that is highly toxic by inhalation and is considered a chemical threat agent. Inhalation of high levels of chlorine results in acute lung injury characterized by pneumonitis, pulmonary edema, and decrements in lung function. Because inflammatory processes can promote damage in the injured lung, anti-inflammatory therapy may be of potential benefit for treating chemical-induced acute lung injury. We previously developed a chlorine inhalation model in which mice develop epithelial injury, neutrophilic inflammation, pulmonary edema, and impaired pulmonary function. This model was used to evaluate nine corticosteroids for the ability to inhibit chlorine-induced neutrophilic inflammation. Two of the most potent corticosteroids in this assay, mometasone and budesonide, were investigated further. Mometasone or budesonide administered intraperitoneally 1 h after chlorine inhalation caused a dose-dependent inhibition of neutrophil influx in lung tissue sections and in the number of neutrophils in lung lavage fluid. Budesonide, but not mometasone, reduced the levels of the neutrophil attractant CXCL1 in lavage fluid 6 h after exposure. Mometasone or budesonide also significantly inhibited pulmonary edema assessed 1 day after chlorine exposure. Chlorine inhalation resulted in airway hyperreactivity to inhaled methacholine, but neither mometasone nor budesonide significantly affected this parameter. The results suggest that mometasone and budesonide may represent potential treatments for chemical-induced lung injury. - Highlights: • Chlorine causes lung injury when inhaled and is considered a chemical threat agent. • Corticosteroids may inhibit lung injury through their anti-inflammatory actions. • Corticosteroids inhibited chlorine-induced pneumonitis and pulmonary edema. • Mometasone and budesonide are potential rescue treatments for chlorine lung injury.

  7. Chlorine Stable Isotopes to reveal contribution of magmatic chlorine in subduction zones: the case of the Kamchatka-Kuril and the Lesser Antilles Volcanic Arcs

    Science.gov (United States)

    Agrinier, Pierre; Shilobreeva, Svetlana; Bardoux, Gerard; Michel, Agnes; Maximov, Alexandr; Kalatcheva, Elena; Ryabinin, Gennady; Bonifacie, Magali

    2015-04-01

    By using the stable isotopes of chlorine (δ 37Cl), we have shown that magmatic chlorine (δ 37Cl ≤ -0.6 ‰ [1]) is different from surface chlorine (δ 37Cl ≈ 0 ‰ [1]) in hydrothermal system of Soufrière and Montagne Pelé from the young arc volcanic system of Lesser Antilles. First measurements on condensed chlorides from volcanic gases (e.g. [2], [3]) did not permitted to get sensible δ 37Cl values on degassed chlorine likely because chlorine isotopes are fractionated during the HClgas - chloride equilibrium in the fumaroles or during sampling artifacts. Therefore we have developed an alternative strategy based on the analysis of chloride in thermal springs, streams, sout{f}lowing on the flanks of the volcanoes. Due to the highly hydrophilic behavior of Cl, we hypothesize that thermal springs incorporate chlorine without fractionation of chlorine isotopes and might reflect the chlorine isotopic composition degassed by magmas [1]. Indeed Thermal spring with low δ 37Cl chlorides (≤ -0.6 perthousand{}) are linked with magmatic volatiles characters (3He ratio at 5 Ra at and δ 13C CO2 quad ≈ -3 perthousand{}). To go further in the potentiality of using the Chlorine isotopes to reveal contribution of magmatic chlorine in volcanic systems, we have started the survey of thermal springs and wells waters in the Kamchatka-Kuril volcanic mature Arc (on sites Mutnovsky, Paratunka, Nalychevsky, Khodutkinsky, Paramushir Island, identified by Taran, 2009 [4] for concentrations of chloride). Preliminary results show δ 37Cl values ranging from 0.5 to -0.2 ‰ and generally higher chloride concentrations. The δ 37Cl values are higher than the value recorded for the young arc volcanic system of lesser Antilles. At present moment very few negative δ 37Cl have been measured in the Kamchatka-Kuril volcanic mature Arc. [1] Li et al., 2015 EPSL in press. [2] Sharp et al. 2010 GCA. [3] Rizzo et al., 2013, EPSL, 371, 134. [4] Taran, 2009, GCA, 73, 1067

  8. Kinetics and pathways of ibuprofen degradation by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Xiang, Yingying; Fang, Jingyun; Shang, Chii

    2016-03-01

    The UV/chlorine advanced oxidation process (AOP), which forms reactive species such as hydroxyl radicals (HO) and reactive chlorine species (RCS) such as chlorine atoms (Cl) and Cl2(-), is being considered as an alternative to the UV/H2O2 AOP for the degradation of emerging contaminants. This study investigated the kinetics and pathways of the degradation of a recalcitrant pharmaceutical and personal care product (PPCP)-ibuprofen (IBP)-by the UV/chlorine AOP. The degradation of IBP followed the pseudo first-order kinetics. The first-order rate constant was 3.3 times higher in the UV/chlorine AOP than in the UV/H2O2 AOP for a given chemical molar dosage at pH 6. The first-order rate constant decreased from 3.1 × 10(-3) s(-1) to 5.5 × 10(-4) s(-1) with increasing pH from 6 to 9. Both HO and RCS contributed to the degradation, and the contribution of RCS increased from 22% to 30% with increasing pH from 6 to 9. The degradation was initiated by HO-induced hydroxylation and Cl-induced chlorine substitution, and sustained through decarboxylation, demethylation, chlorination and ring cleavage to form more stable products. Significant amounts of chlorinated intermediates/byproducts were formed from the UV/chlorine AOP, and four chlorinated products were newly identified. The yield of total organic chlorine (TOCl) was 31.6 μM after 90% degradation of 50 μM IBP under the experimental conditions. The known disinfection by-products (DBPs) comprised 17.4% of the TOCl. The effects of water matrix in filtered drinking water on the degradation were not significant, demonstrating the practicality of the UV/chlorine AOP for the control of some refractory PPCPs. However, the toxicity of the chlorinated products should be further assessed.

  9. Modeling and kinetic characterization of wastewater disinfection using chlorine and UV irradiation.

    Science.gov (United States)

    Mounaouer, Brahmi; Abdennaceur, Hassen

    2016-10-01

    Sewage disinfection has the primary objective of inactivating pathogenic organisms to prevent the dissemination of waterborne diseases. This study analyzed individual disinfection, with chlorine alone, ultraviolet radiation alone, and a combined disinfection process (chlorine-UV radiation). Pseudomonas aeruginosa ATCC 15442, Escherichia coli ATCC 11229, Salmonella typhi ATCC 14028, and Clostridium perfringens were selected to evaluate the efficiency of different disinfection processes. The aim of the present study was to characterize the kinetics of chlorine (as NaHOCl) consumption, to evaluate responses of these bacterial species to the chlorination, the ultraviolet (UV) radiation, and the chlorine/UV disinfection processes in secondary wastewater using a batch laboratory reactor. Another target of this work was to study the modeling of the kinetic of water disinfection by chlorination and/or UV irradiation. Two kinetic models (Chick-Watson and Hom) were tested as to ability to scale disinfection of these bacterial species by different ultraviolet and/or chlorine doses. The results of the kinetics of chlorine consumption showed that monochloramines and trichloramines were the most important forms of residual chlorine as compared to free chlorine and dichloramines. The kinetics of inactivation of all examined bacterial strains showed that the application of the model of Hom in its original form was not representative of this kinetics of inactivation. Modification of this model, considering an initial decline of bacteria during the contact of water with chlorine, improved the results of the model. By the same, results revealed that the involved processes of UV irradiation were too complex to be approached by a simplified formulation, even in the case of specific strains of microorganisms and the use of nearly constant UV radiation intensity. In fact, the results have pointed out that the application of the Chick-Watson law is known to be inadequate to describe

  10. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots

    Science.gov (United States)

    Powell, C. L.; Goltz, M. N.; Agrawal, A.

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~ 1.9 mg L- 1, and initial aqueous [CAH] ~ 150 μg L- 1; cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12 ± 0.01 and 0.59 ± 0.07 d- 1, respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  11. A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes* #

    Science.gov (United States)

    Yi, Ying; Hao, Li-mei; Ma, Shu-ren; Wu, Jin-hui; Wang, Tao; Lin, Song; Zhang, Zong-xing; Qi, Jian-cheng

    2016-01-01

    Objectives: This pilot study of employing chlorine dioxide (CD) gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disinfectant. Methods: An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene (PTFE) tubes (2 m long, inner diameter 1 mm) and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the sporicidal activity of CD gas. Factors including exposure dosage, relative humidity (RH), and flow rate (FR) influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. Results: RH, exposure dosage, organic burden, and the FR through the channel significantly (P<0.05) affected the disinfection efficacy of CD gas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% RH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY (0.46 USD) for each endoscope. Conclusions: The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes. PMID:27381729

  12. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots.

    Science.gov (United States)

    Powell, C L; Goltz, M N; Agrawal, A

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~1.9mgL(-1), and initial aqueous [CAH] ~150μgL(-1); cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12±0.01 and 0.59±0.07d(-1), respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  13. Influence of Plants on Chlorine Cycling in Terrestrial Environments

    Science.gov (United States)

    Montelius, Malin; Thiry, Yves; Marang, Laura; Ranger, Jacques; Cornelis, Jean-Thomas; Svensson, Teresia; Bastviken, David

    2016-04-01

    Chlorine (Cl), one of the 20 most abundant elements on Earth, is crucial for life as a regulator of cellular ionic strength and an essential co-factor in photosynthesis. Chlorinated organic compounds (Clorg) molecules are surprisingly abundant in soils, in fact many studies during the last decades show that Clorg typically account for more than 60% of the total soil Cl pool in boreal and temperate forest soils and frequently exceed chloride (Cl-) levels. The natural and primarily biotic formation of this Clorg pool has been confirmed experimentally but the detailed content of the Clorg pool and the reasons for its high abundance remains puzzling and there is a lack of Cl budgets for different ecosystems. Recently, the radioisotope 36Cl has caused concerns because of presence in radioactive waste, a long half-life (301 000 years), potential high mobility, and limited knowledge about Cl residence times, speciation and uptake by organisms in terrestrial environments. The chlorination of organic molecules may influence the pool of available Cl- to organisms and thereby the Cl cycling dynamics. This will prolong residence times of total Cl in the soil-vegetation system, which affects exposure times in radioactive 36Cl isotope risk assessments. We tested to what extent the dominating tree species influences the overall terrestrial Cl cycling and the balance between Cl- and Clorg. Total Cl and Clorg were measured in different tree compartments and soil horizons in the Breuil experimental forest, Bourgogne, established in 1976 and located at Breuil-Chenue in Eastern France. The results from this field experiment show how the dominating tree species affected Cl cycling and accumulation over a time period of 30 years. Cl uptake by trees as well as content of both total Cl and Clorg in soil humus was much higher in experimental plots with coniferous forests compared to deciduous forests. The amounts of Clorg found in plant tissue indicate significant Clorg production inside

  14. Examination of the kinetics of degradation of the antineoplastic drug 5-fluorouracil by chlorine and bromine.

    Science.gov (United States)

    Li, Wei; Tanumihardja, Jessica; Masuyama, Takaaki; Korshin, Gregory

    2015-01-23

    This study examined the degradation of the widely used antineoplastic drug 5-fluorouracil (5FU) by chlorine and bromine. 5FU was determined to interact readily with free chlorine and bromine but was stable in the presence of chloramine. The removal of 5FU followed a second-order kinetic pattern. Apparent rates (kapp) of 5FU removal by chlorine and bromine were strongly pH dependent and had maximum 14.8M(-1)s(-1) and 1.9×10(3)M(-1)s(-1)kapp values, respectively at pH 7. Modeling of the dependence of the kapp values vs. pH indicated the presence of a relatively acidic (pK 6.4 vs. 8.5 of 5FU per se) 5FU intermediate generated in the presence of halogen species. Spectrophotometric measurements confirmed the increased acidity of 5FU chlorination products and allowed proposing a degradation pathway of 5FU by chlorine. This pathway suggests that 5FU chlorination proceeds via chlorine incorporation at the 6th carbon in the heterocyclic ring of 5FU.

  15. Sequential flow injection determination of chlorine species using a triiodide-selective electrode detector.

    Science.gov (United States)

    Saad, Bahruddin; Wai, Wan Tatt; Ali, Abdussalam Salhin M; Saleh, Muhammad Idiris

    2006-01-01

    A flow injection analysis (FIA) method for the determination of four residual chlorine species, namely combined available chlorine (CAC), free available chlorine (FAC), total available chlorine (TAC) and chlorite (ClO2-) was developed using a flow-through triiodide-selective electrode as a detector. An important strategy of speciation studies utilized the kinetic discrimination of reactions between the CAC and FAC with Fe2+, which was applied to the speciation of FAC, CAC and TAC. The speciation of available chlorine species and chlorite (an oxychlorine species) was achieved by using the same set-up, but using flow streams of different pH. The effects of the pH of the carrier stream, the flow rate and the sample volume were studied. The method exhibited linearity from 2.8 x 10(-6) to 2.8 x 10(-4) M active chlorine (expressed as OCl-) with a detection limit of 1.4 x 10(-6) M. The selectivity of the method was studied by examining the minimum pH for the oxidation of iodide by other oxidants, and also by assessing the potentiometric selectivity coefficients. The proposed method was successfully applied to the determination of chlorine species in tap water, and disinfecting formulations where good agreement occurred between the proposed and standard methods were found.

  16. Oxidative Dissolution of Silver Nanoparticles by Chlorine: Implications to Silver Nanoparticle Fate and Toxicity.

    Science.gov (United States)

    Garg, Shikha; Rong, Hongyan; Miller, Christopher J; Waite, T David

    2016-04-05

    The kinetics of oxidative dissolution of silver nanoparticles (AgNPs) by chlorine is investigated in this work, with results showing that AgNPs are oxidized in the presence of chlorine at a much faster rate than observed in the presence of dioxygen and/or hydrogen peroxide. The oxidation of AgNPs by chlorine occurs in air-saturated solution in stoichiometric amounts with 2 mol of AgNPs oxidized for each mole of chlorine added. Dioxygen plays an important role in OCl(-)-mediated AgNP oxidation, especially at lower OCl(-) concentrations, with the mechanism shifting from stoichiometric oxidation of AgNPs by OCl(-) in the presence of dioxygen to catalytic removal of OCl(-) by AgNPs in the absence of dioxygen. These results suggest that the presence of chlorine will mitigate AgNP toxicity by forming less-reactive AgCl(s) following AgNP oxidation, although the disinfection efficiency of OCl(-) may not be significantly impacted by the presence of AgNPs because a chlorine-containing species is formed on OCl(-) decay that has significant oxidizing capacity. Our results further suggest that the antibacterial efficacy of nanosilver particles embedded on fabrics may be negated when treated with detergents containing strong oxidants, such as chlorine.

  17. Full-scale study of removal effect on Cyclops of zooplankton with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    LIN Tao; CUI Fu-yi; LIU Dong-mei; AN Dong

    2004-01-01

    Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water etc. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

  18. Thermodynamic analysis of the selective chlorination of electric arc furnace dust.

    Science.gov (United States)

    Pickles, C A

    2009-07-30

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  19. Chlorine Disinfection of Atypical Mycobacteria Isolated from a Water Distribution System

    Science.gov (United States)

    Le Dantec, Corinne; Duguet, Jean-Pierre; Montiel, Antoine; Dumoutier, Nadine; Dubrou, Sylvie; Vincent, Véronique

    2002-01-01

    We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C · t value (product of the disinfectant concentration and contact time) of 60 mg · min · liter−1, frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C · t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4°C to 25°C) and a decrease in pH result in better inactivation. PMID:11872446

  20. Thermodynamic analysis of the selective chlorination of electric arc furnace dust

    Energy Technology Data Exchange (ETDEWEB)

    Pickles, C.A., E-mail: pickles-c@mine.queensu.ca [Department of Mining Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

    2009-07-30

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  1. Direct Chlorination Process for geothermal power plant off-gas - hydrogen sulfide abatement

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

    The Direct Chlorination Process removes hydrogen sulfide from geothermal off-gases by reacting hydrogen sulfide with chlorine in the gas phase. Hydrogen chloride and elemental sulfur are formed by this reaction. The Direct Chlorination Process has been successfully demonstrated by an on-site operation of a pilot plant at the 3 M We HPG-A geothermal power plant in the Puna District on the island of Hawaii. Over 99.5% hydrogen sulfide removal was achieved in a single reaction stage. Chlorine gas did not escape the pilot plant, even when 90% excess chlorine gas was used. A preliminary economic evaluation of the Direct Chlorination Process indicates that it is very competitive with the Stretford Process Compared to the Stretford Process, the Direct Chlorination process requires about one-third the initial capital investment and about one-fourth the net daily expenditure. Because of the higher cost of chemicals and the restricted markets in Hawaii, the economic viability of this process in Hawaii is questionable.

  2. Multi-species biofilms defined from drinking water microorganisms provide increased protection against chlorine disinfection.

    Science.gov (United States)

    Schwering, Monika; Song, Joanna; Louie, Marie; Turner, Raymond J; Ceri, Howard

    2013-09-01

    A model biofilm, formed of multiple species from environmental drinking water, including opportunistic pathogens, was created to explore the tolerance of multi-species biofilms to chlorine levels typical of water-distribution systems. All species, when grown planktonically, were killed by concentrations of chlorine within the World Health Organization guidelines (0.2-5.0 mg l(-1)). Higher concentrations (1.6-40-fold) of chlorine were required to eradicate biofilm populations of these strains, ~70% of biofilms tested were not eradicated by 5.0 mg l(-1) chlorine. Pathogenic bacteria within the model multi-species biofilms had an even more substantial increase in chlorine tolerance; on average ~700-1100 mg l(-1) chlorine was required to eliminate pathogens from the biofilm, 50-300-fold higher than for biofilms comprising single species. Confocal laser scanning microscopy of biofilms showed distinct 3D structures and multiple cell morphologies and arrangements. Overall, this study showed a substantial increase in the chlorine tolerance of individual species with co-colonization in a multi-species biofilm that was far beyond that expected as a result of biofilm growth on its own.

  3. Pilot-scale study of removal effect on Chironomid larvae with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

  4. Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes.

    Science.gov (United States)

    Li, Tong; Jiang, Yan; An, Xiaoqiang; Liu, Huijuan; Hu, Chun; Qu, Jiuhui

    2016-10-01

    The synergistic effect of ultraviolet light (UV) and chlorine on the structural transformation of Humic Acid (HA) and formation of chloro-disinfection byproducts (DBPs) in water were investigated, with chlorination as a reference. The transformation and mineralization of HA were enhanced upon co-exposure to UV and chlorine. Electron spin resonance (ESR) studies revealed that hydroxyl radical (OH) and chlorine radical (Cl) were predominant active species in a pH range from 4 to 7, while Cl dominated at pH 2 and pH higher than 7. The impact of different radicals on the transformation of HA was investigated by UV254, fluorescence and TOC measurements. OH were found to be responsible for the removal of chromophoric groups and mineralization of HA, while Cl mainly reacted with HA and intermediates from HA degradation. Due to the competitive and synergistic reaction of OH and Cl with HA, higher removal of HA and lower formation of chloro-DBPs appeared in UV-chlorine than chlorination, thus the combined UV-chlorine processes should be a promising method for water purification.

  5. Photodynamic activity of the boronated chlorin e6 amide in artificial and cellular membranes.

    Science.gov (United States)

    Antonenko, Yuri N; Kotova, Elena A; Omarova, Elena O; Rokitskaya, Tatyana I; Ol'shevskaya, Valentina A; Kalinin, Valery N; Nikitina, Roza G; Osipchuk, Julia S; Kaplan, Mikhail A; Ramonova, Alla A; Moisenovich, Mikhail M; Agapov, Igor I; Kirpichnikov, Mikhail P

    2014-03-01

    Photodynamic tumor-destroying activity of the boronated chlorin e6 derivative BACE (chlorin e6 13(1)-N-{2-[N-(1-carba-closo-dodecaboran-1-yl)methyl]aminoethyl}amide-15(2), 17(3)-dimethyl ester), previously described in Moisenovich et al. (2010) PLoS ONE 5(9) e12717, was shown here to be enormously higher than that of unsubstituted chlorin e6, being supported by the data on much higher photocytotoxicity of BACE in M-1 sarcoma cell culture. To validate membrane damaging effect as the basis of the enhanced tumoricidal activity, BACE was compared with unsubstituted chlorin e6 in the potency to photosensitize dye leakage from liposomes, transbilayer lipid flip-flop, inactivation of gramicidin A ionic channels in planar lipid membranes and erythrocyte hemolysis. In all the models comprising artificial and cellular membranes, the photodynamic effect of BACE exceeded that of chlorin e6. BACE substantially differed from chlorin e6 in the affinity to liposomes and erythrocytes, as monitored by fluorescence spectroscopy, flow cytometry and centrifugation. The results support the key role of membrane binding in the photodynamic effect of the boronated chlorin e6 amide.

  6. Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products.

    Science.gov (United States)

    Zhou, Shiqing; Xia, Ying; Li, Ting; Yao, Tian; Shi, Zhou; Zhu, Shumin; Gao, Naiyun

    2016-08-01

    Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine advanced oxidation process was systematically investigated in this study. The results showed that the UV/chlorine process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine process. Finally, a degradation pathway for CBZ in the UV/chlorine process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine advanced oxidation process to drinking water.

  7. Mass Spectrometry Identification of N-Chlorinated Dipeptides in Drinking Water.

    Science.gov (United States)

    Huang, Guang; Jiang, Ping; Li, Xing-Fang

    2017-03-14

    We report the identification of N-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N,N-di-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, (35)Cl/(37)Cl isotopic patterns, and MS/MS spectra. These identified N-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except N,N-di-Cl-Phe-Gly. To enable sensitive detection of N-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with multiple reaction monitoring (MRM) mode. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the N-chlorinated dipeptides were at background levels. These results suggest that the N-chlorinated dipeptides are produced by chlorination. This study has identified N-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water.

  8. Degradation of atrazine by UV/chlorine: Efficiency, influencing factors, and products.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Liu, Weili; Liu, Yulei

    2016-03-01

    In this work, the degradation of atrazine by the combination of UV and chlorine (UV/chlorine) due to the formation of radicals during chlorine photolysis was systematically investigated in terms of efficiency, factors that influence the degradation kinetics, as well as oxidation products. It was found that the degradation efficiency of atrazine was enhanced by UV/chlorine compared to UV or chlorine alone. The degradation efficiency of atrazine was favorable at a lower pH, but was inhibited in the presence of natural organic matters. Meanwhile, the initial chlorine dosage, alkalinity, and chloride barely influenced the degradation efficiency under neutral pH conditions. The degradation of atrazine by UV/chlorine was inhibited in real waters (i.e., surface water and ground water) compared to in deionized water but was still more effective than UV alone. The oxidation products of atrazine resulting from de-alkylation, dechlorination-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, alkylic-hydroxylation-dehydration, deamination-hydroxylation, and dechlorination-hydrogenation in UV/chlorine process were detected, which were slightly different from those formed in UV/H2O2 (commonly used UV-based advanced oxidation process). Particularly, the yields of three primary transformation products (desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), and desethyl-desisopropyl-atrazine (DEIA)) were comparatively quantified in these two processes. The different trend of them formed in UV/chlorine system (DEA:DIA≈4) compared to that formed in UV/H2O2 system (DEA:DIA≈1) could be ascribed to the different reaction reactivities and mechanisms between HO• and Cl• with atrazine.

  9. Evaluation of the use of chlorine dioxide to control zebra mussels

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Meredosia, IL (United States); Pallo, S. [Illinois Power Company, Clinton, IL (United States)] [and others

    1995-06-01

    Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the two utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received two to four day applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received two to four day applications in July 1993, January, April, May, July, and September 1994. Chlorine dioxide was generated on-site and injected into the water intake structure, in front of or just behind the traveling screens, at both power stations. Both cooling and service water systems were treated at the facilities. Various water quality parameters, including residual chlorine in the discharge effluent, were measured during the studies. Residual chlorine was neutralized with sodium bisulfite prior to discharge at both plants. Bioboxes, containing healthy zebra mussels, were placed at various strategic locations throughout the power stations. Control bioboxes were also placed in the rivers, upstream of the chlorine dioxide injection locations. Results of the chlorine dioxide applications varied from 35 percent to 100 percent. These varied results appear to be related to seasonal water temperature differences, water quality, and/or plant design. Mortality differences were also noted in bioboxes which contained zebra mussels imported from Lake Erie and those which contained local mussels. These and other data are presented.

  10. Formation and chlorination of polychlorinated naphthalenes (PCNs) in the post-combustion zone during MSW combustion.

    Science.gov (United States)

    Jansson, Stina; Fick, Jerker; Marklund, Stellan

    2008-07-01

    Non- to octa-chlorinated naphthalenes (PCNs) were analyzed in flue gas samples collected simultaneously at three different temperatures (450 degrees C, 300 degrees C and 200 degrees C, respectively) in the post-combustion zone during waste combustion experiments using a laboratory-scale fluidized-bed reactor. PCN homologue profiles in all samples were dominated by the lower chlorinated homologues (mono- to triCN), with successive reductions in abundance with each additional degree of chlorination. The isomer distribution patterns reflected ortho-directionality behavior of the first chlorine substituent, and the beta-positions, i.e. the 2,3,6,7-substitution sites, seemed to be favored for chlorination. Injection of naphthalene into the post-combustion zone resulted in increased PCN levels at 200 degrees C, demonstrating the occurrence of chlorination reactions in the post-combustion zone. However, the increases were restricted to the least-chlorinated homologue (monoCN), probably because there was insufficient residence time for further chlorination. In addition, an episode of poor combustion (manifested by high CO levels) was accompanied by extensive formation of 1,8-diCN, 1,2,3- and 1,2,8-triCN; congeners with substitution patterns that are not thermodynamically favorable. These are believed to be products of PAH breakdown reactions and/or chlorophenol condensation. Overall, PCN formation is likely to occur via more than one pathway, including chlorination of naphthalene that is already present, de novo synthesis from PAHs and, possibly, chlorophenol condensation.

  11. Multiphoton ionization of chlorine: the 3Σ u state

    Science.gov (United States)

    Zafiropulos, V.; Fu, G. S.; Hontzopoulos, E.; Fotakis, C.; Castex, M. C.

    1991-04-01

    This work presents the three-photon resonant, one-photon (3 + 1) ionization spectrum of chlorine in the region of 73170-79360 cm -1 above the neutral ground state. In contrast to one-photon experiments, an intense double-peaked band progression attributed to 35Cl 2 and 35Cl 37Cl is observed in this energy region and assigned to a 3Σ u(υ' = 0-7) ← X 1Σ g+ (υ″ = 0) Rydberg excitation. The molecular constants of the 3Σ u Rydberg well as determined from the vibrational progression are T e = 74013 (5) cm -1, ω e = 628 (3) cm -1 and ω eχ e =4.4 (6) cm -1.

  12. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  13. Clinical evaluation of chlorine dioxide for disinfection of dental instruments.

    Science.gov (United States)

    Watamoto, Takao; Egusa, Hiroshi; Sawase, Takashi; Yatani, Hirofumi

    2013-01-01

    This study aimed to clinically evaluate the disinfection efficacy of chlorine dioxide (ClO2) for used dental instruments. An imprint culture technique demonstrated that ultrasonic cleaning of intraorally applied dental mirrors in 0.02% ClO2 for 10 minutes resulted in compete removal of microorganisms for 10 subjects. Hepatitis C virus (HCV) RNA was detected by real-time polymerase chain reaction on periodontal curettes after subgingival scaling in four HCV-infected patients and was completely removed by the same treatment procedure. Therefore, the combination of ultrasonic cleaning with ClO2 may provide an alternative to toxic disinfectants, such as glutaraldehyde and sodium hypochlorite, for disinfecting dental instruments.

  14. Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids.

    Science.gov (United States)

    Wang, Zhentao; Zhu, Lin; Yin, Feng; Su, Zhongquan; Li, Zhaodong; Li, Chaozhong

    2012-03-07

    Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)(2)OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.

  15. Dry Machining Tool Design via Chlorine Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    Tatsuhiko Aizawa; Atsushi Mitsuo; Shigeo Yamamoto; Shinji Muraishi; Taro Sumitomo

    2004-01-01

    Dry machining has become a key issue to significantly reduce the wastes of used lubricants and cleaning agents and to improve the environmental consciousness for medical and food applications of special tooling. Since the tools and metallic works are in direct contact in dry, severe adhesive wear and oxidation are thought to occur even at the presence of hard protective coatings. Self-lubrication mechanism with use of lubricous oxide films is found to be effective for dry machining. Through the chlorine ion implantation to tools, titanium base oxides are in-situ formed on the tool surface.This oxide deforms elasto-plastically so that both friction coefficient and wear volume are reduced even in the high-speed cutting.

  16. Diamagnetic Raman Optical Activity of Chlorine, Bromine, and Iodine Gases.

    Science.gov (United States)

    Šebestík, Jaroslav; Kapitán, Josef; Pačes, Ondřej; Bouř, Petr

    2016-03-01

    Magnetic Raman optical activity of gases provides unique information about their electric and magnetic properties. Magnetic Raman optical activity has recently been observed in a paramagnetic gas (Angew. Chem. Int. Ed. 2012, 51, 11058; Angew. Chem. 2012, 124, 11220). In diamagnetic molecules, it has been considered too weak to be measurable. However, in chlorine, bromine and iodine vapors, we could detect a significant signal as well. Zeeman splitting of electronic ground-state energy levels cannot rationalize the observed circular intensity difference (CID) values of about 10(-4). These are explicable by participation of paramagnetic excited electronic states. Then a simple model including one electronic excited state provides reasonable spectral intensities. The results suggest that this kind of scattering by diamagnetic molecules is a general event observable under resonance conditions. The phenomenon sheds new light on the role of excited states in the Raman scattering, and may be used to probe molecular geometry and electronic structure.

  17. Chlorinated solvent replacements recycle/recovery review report

    Energy Technology Data Exchange (ETDEWEB)

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. (Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering)

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  18. Dry Machining Tool Design via Chlorine Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    TatsuhikoAizawa; AtsushiMitsuo; ShigeoYamamoto; ShinjiMuraishi; TaroSumitomo

    2004-01-01

    Dry machining has become a key issue to significantly reduce the wastes of used lubricants and cleaning agents and to improve the environmental consciousness for medical and food applications of special tooling. Since the tools and metallic works are in direct contact in dry, severe adhesive wear and oxidation are thought to occur even at the presence of hard protective coatings. Self-lubrication mechanism with use of lubricous oxide films is found to be effective for dry machining. Through the chlorine ion implantation to tools, titanium base oxides are in-situ formed on the tool surface. This oxide deforms elasto-plastically so that both friction coefficient and wear volume are reduced even in the high-speed cutting.

  19. Emission characteristics of chlorine in the process of coal and WP co-pyrolysising and exploring on its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Liu, Z.; Zhao, Y.; Shi, Y.; Zhao, S. [Shandong University of Science and Technology, Qingdao (China)

    2007-04-15

    The emission characteristics of chlorine as well a the yield of coke during the process of waste plastic (WP) and coal co-pyrolysis was studied. The result indicates that the emission ratio of chlorine and yield of coke are dependent on pyrolysing temperature, percentage of WP and time of constant temperature. When percentage of WP is big the remains of chlorine in the coke is the same as it in common coal, even though pyrolysis temperature is 1000{sup o}C. However the remains of chlorine in coke decreases with the increase of constant temperature time. So the remains of chlorine in coke can be controlled by controlling the constant temperature time. Additionally, the mechanism of chlorine emission was studied base don the experimental data and comparison with co-pyrolysis of coal and PVC, and a dynamic equation of chlorine emission was derived. 9 refs., 5 figs., 2 tabs.

  20. Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

    Energy Technology Data Exchange (ETDEWEB)

    Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

    2006-03-15

    Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)

  1. Predicting bromide incorporation in a chlorinated indoor swimming pool.

    Science.gov (United States)

    Chowdhury, Shakhawat; Mazumder, Abu Jafar; Husain, Tahir

    2016-06-01

    The water in and air above swimming pools often contain high levels of disinfection byproducts (DBPs) due to chemical reactions between chlorine- or bromine-based disinfectants and organic/inorganic matter in the source water and released from swimmers. Exposure to these DBPs, though inevitable, can pose health threats to humans. In this study, DBPs in tap water (S1), and water from a chlorinated indoor swimming pool before (S2) and after swimming (S3) were measured. The brominated species constituted the majority of DBPs formed in S1, S2, and S3. Trihalomethanes (THMs) in S3 was 6.9 (range 2.9-11.1) and 1.4 (range 0.52-2.9) times those in S1 and S2, respectively; and the haloacetic acids (HAAs) in S3 was 4.2 (range 2.5-7.5) and 1.2 (range 0.6-2.6) times those in S1 and S2, respectively. The mean THMs in air above the swimming pool before (S2-A) and after swimming (S3-A) were 72.2 and 93.0 μg/m(3), respectively, and their ranges were 36.3-105.8 and 44.1-133.6 μg/m(3), respectively. The average percentages of bromide incorporation (BI) into THMs in S1, S2, and S3 were 3.0, 9.3, and 10.6 %, respectively; and the BI into HAAs in S1, S2, and S3 were 6.6, 12.0, and 12.2 %, respectively. Several models were trained for predicting the BI into THMs and HAAs. The results indicate that additional information is required to develop predictive models for BI in swimming pools.

  2. Chlorination of parabens: reaction kinetics and transformation product identification.

    Science.gov (United States)

    Mao, Qianhui; Ji, Feng; Wang, Wei; Wang, Qiquan; Hu, Zhenhu; Yuan, Shoujun

    2016-11-01

    The reactivity and fate of parabens during chlorination were investigated in this work. Chlorination kinetics of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were studied in the pH range of 4.0 to 11.0 at 25 ± 1 °C. Apparent rate constants (k app) of 9.65 × 10(-3) M(-0.614)·s(-1), 1.77 × 10(-2) M(-1.019)·s(-1), 2.98 × 10(-2) M(-0.851)·s(-1), and 1.76 × 10(-2) M(-0.860)·s(-1) for MeP, EtP, PrP, and BuP, respectively, were obtained at pH 7.0. The rate constants depended on the solution pH, temperature, and NH4(+) concentration. The maximum k app was obtained at pH 8.0, and the minimum value was obtained at pH 11.0. The reaction rate constants increased with increasing temperature. When NH4(+) was added to the solution, the reaction of parabens was inhibited due to the rapid formation of chloramines. Two main transformation products, 3-chloro-parabens and 3,5-dichloro-parabens, were identified by GC-MS and LCMS-IT-TOF, and a reaction pathway was proposed. Dichlorinated parabens accumulated in solution, which is a threat to human health and the aqueous environment.

  3. Ecological impact of chloro-organics produced by chlorination of cooling tower waters

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, R L; Cumming, R B; Pitt, W W; Taylor, F G; Thompson, J E; Hartmann, S J

    1977-01-01

    Experimental results of the initial assessment of chlorine-containing compounds in the blowdown from cooling towers and the possible mutagenic activity of these compounds are reported. High-resolution liquid chromatographic separations were made on concentrates of the blowdown from the cooling tower at the High Flux Isotope Reactor (HFIR) and from the recirculating water system for the cooling towers at the Oak Ridge Gaseous Diffusion Plant (ORGDP), Oak Ridge, Tennessee. The chromatograms of chlorinated cooling waters contained numerous uv-absorbing and cerate-oxidizable constituents that are now being processed through a multicomponent identification procedure. Concentrates of the chlorinated waters are also being examined for mutagenic activity.

  4. A CASE STUDY OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ACCIDENTAL RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.; Hunter, C.; Werth, D.; Whiteside, M.; Chen, K.; Mazzola, C.

    2012-08-01

    A train derailment that occurred in Graniteville, South Carolina during the early morning hours of 06 January, 2005 resulted in the prompt release of approximately 60 tons of chlorine to the environment. Comprehensive modeling of the transport and fate of this release was performed including the characterization of the initial three-phased chlorine release, a detailed determination of the local atmospheric conditions acting to generate, disperse, and deplete the chlorine vapor cloud, the establishment of physical exchange mechanisms between the airborne vapor and local surface waters, and local aquatic dilution and mixing.

  5. Heterogeneous chemical reaction of chlorine nitrate and water on sulfuric-acid surfaces at room temperature

    Science.gov (United States)

    Rossi, Michel J.; Malhotra, Ripudaman; Golden, David M.

    1987-01-01

    The use of H2SO4 as a catalyst for aerosol production of chlorine compounds in the chemistry of the antarctic stratosphere was investigated in laboratory trials. The experiments involved the gas surface collision rate of a molecule on a given surface during its residence time in a Knudsen cell in molecular flow conditions. Chlorine nitrate gas was made to flow through a chamber exposed to a container holding a 95.6 pct H2SO4 solution. Gas leaving the cell was scanned with a mass spectrometer. A sticking coefficient of 0.00032 was found for the chlorine nitrate, a value five times that previously reported.

  6. The performance of activated carbons from sugarcane bagasse, babassu, and coconut shells in removing residual chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Jaguaribe, E.F.; Araujo, L.P. [Paraiba Univ., Joao Pessoa, PB (Brazil). Centro de Ciencias da Saude. Lab. de Carvao Ativado]. E-mail:emersonjaguaribe@globo.com; Medeiros, L.L.; Barreto, M.C.S. [Paraiba Univ., Joao Pessoa, PB (Brazil). Dept. de Quimica]. E-mail: luciana-lucena@bol.com.br

    2005-03-01

    The capacity of activated carbons obtained from different raw materials, such as sugarcane bagasse, babassu (Orbygnia speciosa), and coconut (Cocus nucifera) shells, to remove residual chlorine is studied. The influence of particle size and time of contact between particles of activated carbon and the chlorinated solution were taken into account. The adsorptive properties of the activated carbons were measured by gas adsorption (BET method), using an ASAP 2010 porosimeter, and liquid phase adsorption, employing iodine and methylene blue adsorbates. The activated carbon from sugarcane bagasse was the only adsorbent capable of removing 100% of the residual chlorine. (author)

  7. Recovery of actinides from actinide-aluminium alloys by chlorination: Part II

    Science.gov (United States)

    Souček, P.; Cassayre, L.; Eloirdi, R.; Malmbeck, R.; Meier, R.; Nourry, C.; Claux, B.; Glatz, J.-P.

    2014-04-01

    A chlorination route is being investigated for recovery of actinides from actinide-aluminium alloys, which originate from pyrochemical recovery of actinides from spent metallic nuclear fuel by electrochemical methods in molten LiCl-KCl. In the present work, the most important steps of this route were experimentally tested using U-Pu-Al alloy prepared by electrodeposition of U and Pu on solid aluminium plate electrodes. The investigated processes were vacuum distillation for removal of the salt adhered on the electrode, chlorination of the alloy by chlorine gas and sublimation of the AlCl3 formed. The processes parameters were set on the base of a previous thermochemical study and an experimental work using pure UAl3 alloy. The present experimental results indicated high efficiency of salt distillation and chlorination steps, while the sublimation step should be further optimised.

  8. Chlorine isotopic geochemistry of salt lakes in the Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Liu, W.G.; Xiao, Y.K.; Wang, Q.Z.; Qi, H.P.; Wang, Y.H.; Zhou, Y.M.; Shirodkar, P.V.

    and halite precipitation and with the hydrochemistry of the input water. The chlorine isotopic composition may reflect the degree of evaporation of the salt lake brine and may be used to distinguish brine that are in equilibrium with precipitating salts...

  9. SHORTER MENSTRUAL CYCLES ASSOCIATED WITH CHLORINATION BY-PRODUCTS IN DRINKING WATER

    Science.gov (United States)

    Shorter Menstrual Cycles Associated with Chlorination by-Products in Drinking Water. Gayle Windham, Kirsten Waller, Meredith Anderson, Laura Fenster, Pauline Mendola, Shanna Swan. California Department of Health Services.In previous studies of tap water consumption we...

  10. Cl app: android-based application program for monitoring the residue chlorine in water

    Science.gov (United States)

    Intaravanne, Yuttana; Sumriddetchkajorn, Sarun; Porntheeraphat, Supanit; Chaitavon, Kosom; Vuttivong, Sirajit

    2015-07-01

    A farmer usually uses a cheap chemical material called chlorine to destroy the cell structure of unwanted organisms and remove some plant effluents in a baby shrimp farm. A color changing of the reaction between chlorine and chemical indicator is used to monitor the residue chlorine in water before releasing a baby shrimp into a pond. To get rid of the error in color reading, our previous works showed how a smartphone can be functioned as a color reader for estimating the chlorine concentration in water. In this paper, we show the improvement of interior configuration of our prototype and the distribution to several baby shrimp farms. In the future, we plan to make it available worldwide through the online market as well as to develop more application programs for monitoring other chemical substances.

  11. Antimicrobial effect of chlorine dioxide on Actinobacillus actinomycetemcomitans in diabetes mellitus rats treated with insulin

    Directory of Open Access Journals (Sweden)

    Tantin Ermawati

    2012-03-01

    Full Text Available Background: Periodontitis is a chronic inflammatory disease of periodontal tissues. Etiology of periodontal disease includes Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans which is the most predominant disease-causing bacteria found in the gingival sulcus. Periodontitis can be exacerbated by the systemic disease, such as diabetes mellitus considered as a metabolic disease characterized by hyperglycemia due to insulin deficiency. Treatment of periodontitis is then required in patients with type I diabetes to avoid radical reaction that can not only cause bleeding, but can also prevent infection, as a result, topical antimicrobial therapy and blood glucose control are required. Topical antimicrobial chlorine dioxide is a disinfectant that is effective in killing A. actinomycetemcomitans. Purpose: This study is aimed to determine the effects of topical antimicrobial chlorine dioxide gel or rinse on the number of A. actinomycetemcomitans in DM rats treated with insulin. Methods: 20 three month old male Wistar rats with weight of 170–200 grams were divided into four groups. First, periodontitis and DM were manipulated into all groups through aloksan injection with dose of 170 mg/kg. Those rats in group I were treated with insulin and chlorine dioxide gel, those in group II were treated with insulin and chlorine dioxide rinse, those in group III were treated with insulin only, and those in group IV were without treatment. In the third and seventh weeks, the number of A. actinomycetemcomitans was measured. The data was tested by using One-Way ANOVA test followed by LSD test. Results: The study showed that chlorine dioxide gel has a greater ability in reducing the number of A. actinomycetemcomitans than chlorine dioxide rinse although both are antimicrobials. Conclusion: It can be concluded that the use of chlorine dioxide gel can more effective to decrease the number of A. actinomycetemcomitans than chlorine dioxide rinse in DM rats

  12. Stability and toxicity of selected chlorinated benzophenone-type UV filters in waters.

    Science.gov (United States)

    Zhuang, Rensheng; Žabar, Romina; Grbović, Gorica; Dolenc, Darko; Yao, Jun; Tišler, Tatjana; Trebše, Polonca

    2013-01-01

    In our study, the transformation of two most widely used UV filters, benzophenone-3 (BP3) and benzophenone-4 (BP4), in chlorinated water with disinfection reagents sodium hypochlorite (NaClO) and trichloroisocyanuric acid (TCCA) was studied. Based on the HPLC/MS and UV-Vis analysis the formation of two different chlorinated products (5-chloro-2-hydroxy-4-methoxybenzophenone and 3,5-dichloro-2-hydroxy-4-methoxybenzophenone) was established. Identity of chlorinated products was confirmed by means of comparison of retention times with independently synthesized standards. Photostability study showed that dichloro-derivative in water is less stable then parent compounds, which is not the case for monochloro-derivatives. Toxicity of chlorinated compounds tested by Vibrio fischeri was found to be in the same range as that of the starting compounds. Preliminary testing of real water samples from swimming pools and sea swimming areas confirmed the presence of BP3 and its 3,5-dichloro derivative.

  13. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE DISINFECTION BY-PRODUCTS IN DRINKING WATER

    Science.gov (United States)

    This paper discusses the identification of organic disinfection by-products (DBPs) at a pilot plant in Evansville, Indiana, that uses chlorine dioxide as a primary disinfectant. nconventional multispectral identification techniques (gas chromatography combined with high and low r...

  14. Fluorine and chlorine determination in mixed uranium-plutonium oxide fuel and plutonium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Elinson, S.V.; Zemlyanukhina, N.A.; Pavlova, I.V.; Filatkina, V.P.; Tsvetkova, V.T.

    1981-01-01

    A technique of fluorine and chlorine determination in the mixed uranium-plutonium oxide fuel and plutonium dioxide, based on their simultaneous separation by means of pyrohydrolysis, is developed. Subsequently, fluorine is determined by photometry with alizarincomplexonate of lanthanum or according to the weakening of zirconium colouring with zylenol orange. Chlorine is determined using the photonephelometric method according to the reaction of chloride-ion interaction with silver nitrate or by spectrophotometric method according to the reaction with mercury rhodanide. The lower limit of fluorine determination is -6x10/sup -5/ %, of chlorine- 1x10/sup -4/% in the sample of 1g. The relative mean quadratic deviation of the determination result (Ssub(r)), depends on the character of the material analyzed and at the content of nx10/sup -4/ - nx10/sup -3/ mass % is equal to from 0.05 to 0.32 for fluorine and from 0.11 to 0.35 for chlorine.

  15. Sterilization of hydrogen peroxide resistant bacterial spores with stabilized chlorine dioxide.

    Science.gov (United States)

    Friedline, Anthony; Zachariah, Malcolm; Middaugh, Amy; Heiser, Matt; Khanna, Neeraj; Vaishampayan, Parag; Rice, Charles V

    2015-01-01

    Bacillus pumilus SAFR-032 spores isolated from a clean room environment are known to exhibit enhanced resistance to peroxide, desiccation, UV radiation and chemical disinfection than other spore-forming bacteria. The survival of B. pumilus SAFR-032 spores to standard clean room sterilization practices requires development of more stringent disinfection agents. Here, we report the effects of a stabilized chlorine dioxide-based biocidal agent against spores of B. pumilus SAFR-032 and Bacillus subtilis ATCC 6051. Viability was determined via CFU measurement after exposure. Chlorine dioxide demonstrated efficacy towards sterilization of spores of B. pumilus SAFR-032 equivalent or better than exposure to hydrogen peroxide. These results indicate efficacy of chlorine dioxide delivered through a stabilized chlorine dioxide product as a means of sterilization of peroxide- and UV-resistant spores.

  16. Selective chlorine dioxide determination using gas-diffusion flow injection analysis with chemiluminescent detection

    Energy Technology Data Exchange (ETDEWEB)

    Hollowell, D.A.; Gord, J.R.; Gordon, G.; Pacey, G.E.

    1986-06-01

    An automated chemiluminescent technique has been developed utilizing the advantages of gas-diffusion flow injection analysis. A gas-diffusion membrane separates the donor (sampling) stream from the acceptor (detecting) stream and removes ionic interferences. A novel chemiluminescence flow-through detector cell is used to measure the concentration of chlorine dioxide as a function of the intensity of the chemiluminescence produced from its reaction with luminol. The chemiluminescent reagent merges with the analyte directly in front of the photomultiplier tube in order to maximize the sensitivity of the system. The detection limit for chlorine dioxide is approximately 5 ppb. The method is over 1500 times more selective for chlorine dioxide than for chlorine on a mole basis. This method eliminates interference from iron and manganese compounds, as well as other oxychlorinated compounds such as chlorite ion and chlorate ion.

  17. Evaluation of Chlorine Dioxide Irrigation Solution on the Microhardness and Surface Roughness of Root Canal Dentin.

    Science.gov (United States)

    Ballal, Nidambur Vasudev; Khandewal, Deepika; Karthikeyan, Saravana; Somayaji, Krishnaraj; Foschi, Federico

    2015-12-01

    The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1: 13.8% chlorine dioxide, Group 2: 17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5 ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth.

  18. Impact of chlorine dioxide and ozone on the oxidation of NTA during drinking water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hrubec, J.; ' t Hart, M.J.; Marsman, P.; Luijten, J.A.

    1984-11-01

    The use, as it is proposed, of nitrilotriacetic acid (NTA) for phosphate replacement in detergents will lead to its discharge in surface water at relatively high concentrations. Questions have been raised about potential health hazards related to the uptake and treatment of the NTA containing riverwater for drinking water supply. Degradation of NTA by biological oxidation in waste water treatment systems, soil and surface water under aerobic conditions has been demonstrated many times. However reports on degradation of NTA by chemical oxidation applied in water treatment processes are scarce. The aim of the present investigation was to determine removal of nitrilotriacetic acid upon chlorine, chlorine dioxide and ozone treatment under conditions characteristic for drinking water treatment practice; possible formation of mutagenic substances from the reaction of NTA with these oxidants; and formation of halogenated reaction products of NTA with chlorine and chlorine dioxide.

  19. Chlorine oxide in the stratospheric ozone layer Ground-based detection and measurement

    Science.gov (United States)

    Parrish, A.; De Zafra, R. L.; Solomon, P. M.; Barrett, J. W.; Carlson, E. R.

    1981-01-01

    Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured by a ground-based 204 GHz, millimeter-wave receiver. Data taken at latitude 42 deg N on 17 days between January 10 and February 18, 1980 yield an average chlorine oxide column density of approximately 1.05 x 10 to the 14th/sq cm or approximately 2/3 that of the average of eight in situ balloon flight measurements (excluding the anomalously high data of July 14, 1977) made over the past four years at 32 deg N. Less chlorine oxide below 35 km and a larger vertical gradient than predicted by theoretical models of the stratospheric ozone layer are found.

  20. Assessing the Fate and Transformation By-Product Potential of Trenbolone during Chlorination

    Science.gov (United States)

    Chlorine disinfection is an effective means for managing microbiological activity during drinking water treatment and can eliminate a number of known organic contaminants. Trenbolone is an androgenic steroidal hormone used primarily as a growth stimulant in the animal feedstock ...

  1. Prompt gamma-ray analysis of chlorine in superpozz cement concrete

    Energy Technology Data Exchange (ETDEWEB)

    Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Kalakada, Zameer [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Ur-Rehman, Khateeb [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2012-11-21

    The chlorine concentration in Superpozz (SPZ) cement concrete was analyzed using a newly designed prompt gamma-ray neutron activation (PGNAA) setup utilizing a portable neutron generator. The setup, which mainly consists of a neutron source along with its moderator placed side by side with a shielded gamma-ray detector, allows determining chloride concentration in a concrete structure from one side. The setup has been tested through chlorine detection in chloride-contaminated Superpozz (SPZ) cement concrete specimens using 6.11 and 2.86{+-}3.10 MeV chlorine prompt gamma-rays. The optimum 0.032{+-}0.012 wt% value of Minimum Detectable Concentration (MDC) of chlorine in SPZ cement concrete measured in this study shows a successful application of a portable neutron generator in chloride analysis of concrete structure for corrosion studies.

  2. Review of reactive kinetic models describing reductive dechlorination of chlorinated ethenes in soil and groundwater

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Bjerg, Poul Løgstrup; Scheutz, Charlotte;

    2013-01-01

    Reductive dechlorination is a major degradation pathway of chlorinated ethenes in anaerobic subsurface environments, and reactive kinetic models describing the degradation process are needed in fate and transport models of these contaminants. However, reductive dechlorination is a complex biologi...

  3. BIOVENTING OF CHLORINATED SOLVENTS FOR GROUND-WATER CLEANUP THROUGH BIOREMEDIATION

    Science.gov (United States)

    Chlorinated solvents such as tetrachloroethylene, trichloroethylene, carbon tetrachloride, chloroform, 1,2-dichloroethane, and dichloromethane (methylene chloride) can exist in contaminated subsurface material as (1) the neat oil, (2) a component of a mixed oily waste, (3) a solu...

  4. Research on the Preparation of Crosslinked Starch Chlorinated with Sodium Hypochlorite

    Institute of Scientific and Technical Information of China (English)

    LiangYin; ZhuZhi-feng

    2003-01-01

    Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with form-aldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.

  5. Research on the Preparation of Crosslinked Starch Chlorinated with Sodium Hypochlorite

    Institute of Scientific and Technical Information of China (English)

    Liang Yin; Zhu Zhi-feng

    2003-01-01

    Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with formaldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.

  6. O2(1△) Yield Measurement by Raman Spectroscopy With Elimination of Chlorine Fluorescence Interference

    Institute of Scientific and Technical Information of China (English)

    Rong-rong Cui; Wen-bo Shi; Lie-zheng Deng; He-ping Yang; Guo-he Sha; Cun-hao Zhang

    2012-01-01

    Deleterious chlorine fluorescence was found to occur at the same frequency as the Raman scattering of O2(1△) and O2(3∑),seriously affecting the O2(1△) yield measurement in the reaction of chlorine with basic hydrogen peroxide by use of the Raman spectroscopy technique.To solve this problem we have taken advantage of the fact that Raman radiation is always strongly polarized while fluorescence is essentially non-polarized in a gaseous medium.When chlorine utilization of a singlet oxygen generator is 88%,O2(1△) yield reaches (42.4±7.4)%with the effect of chlorine fluorescence completely eliminated.

  7. Bench and Full Scale Study of Removal Effect and Mutagenicity on Mesocyclops Leukarti with Chlorine Dioxide

    Institute of Scientific and Technical Information of China (English)

    ZUO Jin-long; YANG Wei; LIU Yan-an; LIN Tao

    2006-01-01

    Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In this paper, a study of removal efficiency on Mesocyclops Leukarti with chlorine dioxide in a drinking waterworks was performed.Bench scale results showed that chlorine dioxide is more effective against Mesocyclops Leukarti. And Mesocyclops Leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation cooperated with the conventional process during the full scale study. The chlorite, by-preduct of prechlorine dioxide, was constant at 0.45 mg/L after filtration, which was lower than the critical value of the USEPA. GC-MS examination and Ames test showed that the quantity of organics and the mutagenicity in the water treated by chlorine dioxide is obviously less than that of prechlorination.

  8. Chlorine sensing properties of zinc oxide resistive gas sensor doped with platinum

    Science.gov (United States)

    Fiedot, M.; Suchorska-Woźniak, P.; Rac, O.; Nawrot, W.; Teterycz, H.

    2016-11-01

    In presented studies resistive chlorine gas sensor with gas sensitive layer in the form of zinc oxide microrods doped with platinum was developed. The growth of active layer was carried out in water solution containing zinc nitrate (V), hexamethylenetetramine and chloroplatinic acid using the chemical bath deposition method. The structure and morphology of obtained sensors was characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). To determine the chlorine gas sensing properties Temperature-Stimulated Conductance method (TSC) was used. During the measurements sensor was tested in a reference atmosphere and an atmosphere with 2, 5 or 8 ppm of chlorine. Obtained results have shown that zinc oxide microrods doped with platinum were obtained. TSC measurements showed that developed sensor allows to detect chlorine with very good sensitivity.

  9. Aerobic degradation of highly chlorinated polychlorobiphenyls by a marine bacterium, Pseudomonas CH07

    Digital Repository Service at National Institute of Oceanography (India)

    De, J.; Ramaiah, N.; Sarkar, A.

    : jaysankarde@yahoo.com. Introduction Polychlorinated biphenyls (PCBs) are a class of compounds where the aromatic biphenyl rings carry one to ten chlorine atoms and, theoretically, 209 different PCB congeners can thus be produced. Due to their non... are the ultimate global sinks for worldwide accumulations of PCBs (Berkaw et al., 1996). The toxicity of different congeners of PCBs varies according to the chlorine substitution at different positions of the biphenyl ring and the physical effects of PCBs vary...

  10. Polar stratospheric cloud evolution and chlorine activation measured by CALIPSO and MLS, and modeled by ATLAS

    Directory of Open Access Journals (Sweden)

    H. Nakajima

    2016-03-01

    TNAT. Furthermore, simulations of the ATLAS chemistry and transport box model along the trajectories were used to corroborate the measurements and show good agreement with the observations. Rapid chlorine activation was observed when an air mass encountered PSCs. Usually, chlorine activation was limited by the amount of available ClONO2. Where ClONO2 was not the limiting factor, a large dependence on temperature was evident.

  11. Determination of Short-Chain Chlorinated Paraffins by Carbon Skeleton Gas Chromatography

    OpenAIRE

    PELLIZZATO FRANCESCA; RICCI MARINA; HELD ANDREA; EMONS HENDRIK

    2008-01-01

    Short-Chain Chlorinated Paraffins (SCCPs) are highly complex technical mixtures of polychlorinated n-alkanes with a chlorination degree between 50 and 70 % by mass, and a linear carbon chain length from C10 to C13, constituted by thousands of homologues, diastereomers and enantiomers. They have been used in many different applications, such as extreme pressure additives in lubricants and cutting fluids, plasticizers in PVC, and flame retardants in paints, adhesives and sealants. SCCPs are tox...

  12. Water Quality Impacts of Pure Chlorine Dioxide Pretreatment at the Roanoke County (Virginia) Water Treatment Plant

    OpenAIRE

    Ellenberger, Christine Spada

    1999-01-01

    WATER QUALITY IMPACTS OF PURE CHLORINE DIOXIDE PRETREATMENT AT THE ROANOKE COUNTY (VIRGINIA) WATER TREATMENT PLANT by Christine S. Ellenberger Dr. Robert C. Hoehn, Chairman (ABSTRACT) Chlorine dioxide (ClO2) was included in the Spring Hollow Water Treatment Plant (Roanoke County, Virginia) to oxidize manganese and iron, prevent tastes and odors, and avoid the formation of excessive halogenated disinfection by-products. A state-of-the-art, gas:solid ClO2 generation system ...

  13. Monitoring of Coliforms and chlorine residual in water distribution network of Rawalpindi, Pakistan.

    Science.gov (United States)

    Farooq, Shaukat; Hashmi, Imran; Qazi, Ishtiaq A; Qaiser, Sara; Rasheed, Sajida

    2008-05-01

    The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02-7.30; turbidity varied from 0.34-2.79 NTU; conductivity fluctuated from 359-374 microS/cm; and TDS values were found to be ranging between 180-187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, respectively. Highest standard plate count was 62 CFU/ml at Station # 7. Total coliforms were less than 1.1 MPN/100 ml at almost most of the stations except at Station # 3 where it was found to be greater than 23.0 MPN /100 ml. Overall aim of this study is to create awareness about contamination of drinking water in the water distribution networks and to make recommendations to provincial agencies such as EPA, CDA and WASA that regular monitoring should be carried out to ensure that the chlorine residual is available at consumer end.

  14. Isotopic evidence for quick freshening of magmatic chlorine in the Lesser Antilles arc volcanoes

    Science.gov (United States)

    Li, L.; Jendrzejewski, N.; Aubaud, C. P.; Bonifacie, M.; Crispi, O.; Dessert, C.; Agrinier, P.

    2012-12-01

    Despite numerous geophysical and geochemical monitoring techniques developed over the last 50 years to detect magma activities in volcanoes, it is still challenging to evaluate the state of magmatic activity during its decreasing phase (transitory quiet stage and/or final stage of the magma intrusion which may last for decades) for those infrequent, slow developing, and dangerous explosive eruptive arc volcanoes, attributed to the interaction between the magma and hydrothermal cells at shallow depths to produce complex phreato-magmatic events. Recent studies have implied that chloride in intrusion-induced thermal springs could be a potential sensitive indicator of shallow magma degassing. However, possible contamination from surface chlorine reservoirs, such as seawater, may overprint the magmatic signature and complicate the interpretation of field observation. Here, based on chlorine isotope examination of various water samples from two recently erupted volcanoes in the Lesser Antilles arc (Soufrière in Guadeloupe: phreatic eruption in1976-1977; Montagne Pelée in Martinique: pelean eruption in 1929-1932), we show that magmatic chlorine is isotopically distinct from surface chlorine (seawater, meteoric water, and ground water). A chlorine isotopic survey on thermal springs in Guadeloupe and Martinique indicate that the magmatic chlorine signature is still present in some of the thermal springs in Guadeloupe but completely disappeared in Martinique. This suggests that magmatic chlorine be rapidly flushed from hydrothermal system within < 30 to 80 years after the magmatic eruption. This enables chlorine isotopes to be a sensitive proxy to monitor shallow magmatic activities, particularly practicable at centennial scale.

  15. Enhancing the efficacy of electrolytic chlorination for ballast water treatment by adding carbon dioxide.

    Science.gov (United States)

    Cha, Hyung-Gon; Seo, Min-Ho; Lee, Heon-Young; Lee, Ji-Hyun; Lee, Dong-Sup; Shin, Kyoungsoon; Choi, Keun-Hyung

    2015-06-15

    We examined the synergistic effects of CO2 injection on electro-chlorination in disinfection of plankton and bacteria in simulated ballast water. Chlorination was performed at dosages of 4 and 6ppm with and without CO2 injection on electro-chlorination. Testing was performed in both seawater and brackish water quality as defined by IMO G8 guidelines. CO2 injection notably decreased from the control the number of Artemia franciscana, a brine shrimp, surviving during a 5-day post-treatment incubation (1.8 and 2.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO+CO2) compared with water electro-chlorinated only (1.2 and 1.3 log10 reduction in seawater and brackish water, respectively at 6ppm TRO). The phytoplankton Tetraselmis suecica, was completely disinfected with no live cell found at >4ppm TRO with and without CO2 addition. The effects of CO2 addition on heterotrophic bacterial growth was not different from electro-chlorination only. Total residual oxidant concentration (TRO) more rapidly declined in electro-chlorination of both marine and brackish waters compared to chlorine+CO2 treated waters, with significantly higher amount of TRO being left in waters treated with the CO2 addition. Total concentration of trihalomethanes (THMs) and haloacetic acids (HAAs) measured at day 0 in brackish water test were found to be 2- to 3-fold higher in 6ppm TRO+CO2-treated water than in 6ppm TRO treated water. The addition of CO2 to electro-chlorination may improve the efficiency of this sterilizing treatment of ballast water, yet the increased production of some disinfection byproducts needs further study.

  16. Formation of new brominated disinfection byproducts during chlorination of saline sewage effluents.

    Science.gov (United States)

    Ding, Guoyu; Zhang, Xiangru; Yang, Mengting; Pan, Yang

    2013-05-15

    Chlorination could be the most cost-effective method for disinfecting saline sewage effluents resulting from toilet flushing with seawater. Upon chlorination, the high levels of bromide ions in saline sewage effluents (up to 32 mg/L) can be oxidized to hypobromous acid/hypobromite, which could then react with organic matter in the sewage effluents to form brominated disinfection byproducts (Br-DBPs). In this study, primary and secondary saline sewage effluents were collected and chlorinated at different chlorine doses, and a powerful precursor ion scan method using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry was adopted for detection and identification of polar Br-DBPs in these samples. With the new method, 54 major polar Br-DBPs were detected in the chlorinated saline effluents and six of them were newly identified as wastewater DBPs, including bromomaleic acid, 5-bromosalicylic acid, 3,5-dibromo-4-hydroxybenzaldehyde, 3,5-dibromo-4-hydroxybenzoic acid, 2,6-dibromo-4-nitrophenol, and 2,4,6-tribromophenol. The formation of polar Br-DBPs, especially those newly detected ones, during chlorination of the saline effluents was studied. For the secondary saline effluent, various polar Br-DBPs formed and reached their maximum levels at different chlorine doses, whereas for the primary saline effluent, the formation of polar Br-DBPs basically kept increasing with increasing chlorine dose. Compared with the secondary saline effluent, the primary saline effluent generated fewer and less Br-DBPs and rarely generated nitrogenous Br-DBPs.

  17. Kinetics of the oxidation of cylindrospermopsin and anatoxin-a with chlorine, monochloramine and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Sordo, Ana; Metcalf, James S; Acero, Juan L

    2007-05-01

    Cyanobacteria produce toxins that may contaminate drinking water sources. Among others, the presence of the alkaloid toxins cylindrospermopsin (CYN) and anatoxin-a (ANTX) constitutes a considerable threat to human health due to the acute and chronic toxicity of these compounds. In the present study, not previously reported second-order rate constants for the reactions of CYN and ANTX with chlorine and monochloramine and of CYN with potassium permanganate were determined and the influence of pH and temperature was established for the most reactive cases. It was found that the reactivity of CYN with chlorine presents a maximum at pH 7 (rate constant of 1265 M(-1)s(-1)). However, the oxidation of CYN with chloramine and permanganate are rather slow processes, with rate constants <1 M(-1)s(-1). The first chlorination product of CYN was found to be 5-chloro-CYN (5-Cl-CYN), which reacts with chlorine 10-20 times slower than the parent compound. The reactivity of ANTX with chlorine and chloramines is also very low (k<1M(-1)s(-1)). The elimination of CYN and ANTX in surface water was also investigated. A chlorine dose of 1.5 mg l(-1) was enough to oxidize CYN almost completely. However, 3 mg l(-1) of chlorine was able to remove only 8% of ANTX, leading to a total formation of trihalomethanes (TTHM) at a concentration of 150 microg l(-1). Therefore, chlorination is a feasible option for CYN degradation during oxidation and disinfection processes but not for ANTX removal. The permanganate dose required for CYN oxidation is very high and not applicable in waterworks.

  18. Identification of Some AOX Compounds Formed in Wool Chlorination Using Model Chemicals

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; HE Jin-xin; DAJ Jin-jin

    2002-01-01

    The AOX (adsorbable organic halogens) problem in wool shrinkproofing effluents has attracted more attention in recent years. The probable origins and structures of AOX compounds were proved by the reaction of DCCA with the model substances of different amino acid residues.The GC-MS results indicated that available chlorine could chlorinate the side chain of tyrosine, histidine and trypotophan and generate AOX load in the effluent.

  19. Chloride and organic chlorine in forest soils: storage, residence times, and influence of ecological conditions.

    Science.gov (United States)

    Redon, Paul-Olivier; Abdelouas, Abdesselam; Bastviken, David; Cecchini, Sébastien; Nicolas, Manuel; Thiry, Yves

    2011-09-01

    Recent studies have shown that extensive chlorination of natural organic matter significantly affects chlorine (Cl) residence time in soils. This natural biogeochemical process must be considered when developing the conceptual models used as the basis for safety assessments regarding the potential health impacts of 36-chlorine released from present and planned radioactive waste disposal facilities. In this study, we surveyed 51 French forested areas to determine the variability in chlorine speciation and storage in soils. Concentrations of total chlorine (Cl(tot)) and organic chlorine (Cl(org)) were determined in litterfall, forest floor and mineral soil samples. Cl(org) constituted 11-100% of Cl(tot), with the highest concentrations being found in the humus layer (34-689 mg Cl(org) kg(-1)). In terms of areal storage (53 - 400 kg Cl(org) ha(-1)) the mineral soil dominated due to its greater thickness (40 cm). Cl(org) concentrations and estimated retention of organochlorine in the humus layer were correlated with Cl input, total Cl concentration, organic carbon content, soil pH and the dominant tree species. Cl(org) concentration in mineral soil was not significantly influenced by the studied environmental factors, however increasing Cl:C ratios with depth could indicate selective preservation of chlorinated organic molecules. Litterfall contributions of Cl were significant but generally minor compared to other fluxes and stocks. Assuming steady-state conditions, known annual wet deposition and measured inventories in soil, the theoretical average residence time calculated for total chlorine (inorganic (Cl(in)) and organic) was 5-fold higher than that estimated for Cl(in) alone. Consideration of the Cl(org) pool is therefore clearly important in studies of overall Cl cycling in terrestrial ecosystems.

  20. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Science.gov (United States)

    Cassayre, L.; Souček, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P.

    2011-07-01

    Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl 3. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl 3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl 2/UAl 3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl 5 and UCl 6. The results showed high efficient chlorination at a temperature of 150 °C.

  1. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments.

    Science.gov (United States)

    Li, Jian; Ma, Li-yun; Xu, Li

    2016-07-01

    The present study focused on the kinetics, transformation pathways and toxicity of several benzophenone-type ultraviolet filters (BPs) during the water chlorination disinfection process. The transformation kinetics of the studied three BPs was found to be second-order reaction, which was dependent on the concentration of BPs and chlorine. The second-order rate constants increased from 86.7 to 975 M(-1) s(-1) for oxybenzone, 49.6-261.7 M(-1) s(-1) for 4-hydroxybenzophenone and 51.7-540 M(-1) s(-1) for 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid with the increasing pH value from 6 to 8 of the chlorination disinfection condition. Then the transformation products (TPs) of these BPs were identified by HPLC-QTof analysis. Several transformation pathways, including electrophilic substitution, methoxyl substitution, ketone groups oxidation, hydrolysis, decarboxylation and ring cleavage reaction, were speculated to participate in the chlorination transformation process. Finally, according to the toxicity experiment on luminescent bacteria, Photobacterium phosphoreum, enhanced toxicity was observed for almost all the TPs of the studied BPs except for 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; it suggested the formation of TPs with more toxic than the parent compounds during the chlorination process. The present study provided a foundation to understand the transformation of BPs during chlorination disinfection process, and was of great significance to the drinking water safety.

  2. Chlorine behavior during co-hydrothermal treatment of high alkali coal and PVC

    Science.gov (United States)

    Huang, N.; Zhao, P. T.; Li, Z. Z.; Li, T.

    2016-08-01

    The hydrothermal treatment (HT) is an effective method to remove chlorine from chlorinated wastes under mild conditions. However, the alkali was required to improve the dechlorination efficiency. Meanwhile, the alkalis contents removed was necessary to realize the clean and highly efficient utilization of coal. This work was trying to investigate the feasibility of simultaneously removal alkalis and chlorine by co-hydrothermal treatment of PVC and high-alkali coal. The effect of operating conditions including the HT temperature, the holding time and particle sizes of coal on the dechlorination efficiency (DE) of PVC during the HT process was experimentally studied in this work. The results show that the DE increased with the rise of: 1) particle sizes (0.054~0.22mm), 2) holding time (30~90 min) and 3) temperature (240~300 °C). In detail, under 300 °C and 60min of holding time, the 85.18% of DE with first PS was lower than the 93.93% of DE with second PS and 100% of DE with third PS. The organic chlorine mainly transferred into chloridion in aqueous solution in HT process. All the results indicate that it is a prospective way to simultaneously removal alkalis and chlorine by co-hydrothermal treatment of chlorinated wastes and high-alkali coal.

  3. Exposure to chlorine dioxide gas for 4 hours renders Syphacia ova nonviable.

    Science.gov (United States)

    Czarra, Jane A; Adams, Joleen K; Carter, Christopher L; Hill, William A; Coan, Patricia N

    2014-07-01

    The purpose of our study was to evaluate the efficacy of chlorine dioxide gas for environmental decontamination of Syphacia spp. ova. We collected Syphacia ova by perianal cellophane tape impression of pinworm-infected mice. Tapes with attached ova were exposed to chlorine dioxide gas for 1, 2, 3, or 4 h. After gas exposure, ova were incubated in hatching medium for 6 h to promote hatching. For controls, tapes with attached ova were maintained at room temperature for 1, 2, 3, and 4 h without exposure to chlorine dioxide gas and similarly incubated in hatch medium for 6 h. Ova viability after incubation was assessed by microscopic examination. Exposure to chlorine dioxide gas for 4 h rendered 100% of Syphacia spp. ova nonviable. Conversely, only 17% of ova on the 4-h control slide were nonviable. Other times of exposure to chlorine dioxide gas resulted in variable effectiveness. These data suggest that exposure to chlorine dioxide gas for at least 4 h is effective for surface decontamination of Syphacia spp. ova.

  4. Chloroxyanion Residues in Cantaloupe and Tomatoes after Chlorine Dioxide Gas Sanitation.

    Science.gov (United States)

    Smith, D J; Ernst, W; Herges, G R

    2015-11-04

    Chlorine dioxide gas is effective at cleansing fruits and vegetables of bacterial pathogens and(or) rot organisms, but little data are available on chemical residues remaining subsequent to chlorine gas treatment. Therefore, studies were conducted to quantify chlorate and perchlorate residues after tomato and cantaloupe treatment with chlorine dioxide gas. Treatments delivered 50 mg of chlorine dioxide gas per kg of tomato (2-h treatment) and 100 mg of gas per kg of cantaloupe (6-h treatment) in sealed, darkened containers. Chlorate residues in tomato and cantaloupe edible flesh homogenates were less than the LC-MS/MS limit of quantitation (60 and 30 ng/g respectively), but were 1319 ± 247 ng/g in rind + edible flesh of cantaloupe. Perchlorate residues in all fractions of chlorine dioxide-treated tomatoes and cantaloupe were not different (P > 0.05) than perchlorate residues in similar fractions of untreated tomatoes and cantaloupe. Data from this study suggest that chlorine dioxide sanitation of edible vegetables and melons can be conducted without the formation of unwanted residues in edible fractions.

  5. Development and trends in chlorine dioxide bleaching with integrated chlorate electrolysis for the cellulose industry

    Energy Technology Data Exchange (ETDEWEB)

    Wintzer, P.

    1980-05-01

    Rising demand for cellulose and paper and the environmental measures necessary in this branch of industry compel the companies involved to invest large sums. In particular, waste water from bleaching operations causes difficulties in biological waste water purification owing to high chlorolignin content. The sequence of chlorination steps have been optimized for each quality of wood, and the increasing use of chlorine dioxide leads to an expansion of chlorate electrolysis and chlorine dioxide plant at the expense of chlorine. The consumption of chemicals for the various cellulose qualities is considered. During the past 30 years, the Muenchner process for production of ClO/sub 2/ has proved environmentally sound and is being continuously improved. Only hydrochloric acid and water are needed as raw materials. The chlorine formed in this process is converted into hydrochloric acid, hypochlorite, and chlorine water. All steps of the processes require only liquids and gases permitting a favourable, closed mode of operation without by-products or waste salts. New chlorate cells built since 1969 are equipped exclusively with coated titanium anodes (load between 6 and 100 kA) with DC efficiencies of 92 to 95%. Annual world production of sodium chlorate exceeds 1 million tonnes. The rate of increase has long remained steady at 5%.

  6. Elimination of the reactivation process in the adhesion of chlorinated SBS rubber with polychloroprene adhesives

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available Chlorination treatment of a thermoplastic styrene-butadiene-styrene rubber (SBS with a 3 wt% solution of trichloroisocyanuric acid (TCI in methyl ethyl ketone (MEK introduces chlorinated and oxidized moieties on the rubber surface which increase its surface energy and produces surface microroughness. Consequently adhesion properties, evaluated by T-peel strength measurements in chlorinated SBS/solvent based-polyurethane adhesive/leather joints, are enhanced. In this study, two solvent-based polychloroprene adhesives (PCP0 and PCP30R have been considered as an alternative to the commonly used solvent-based polyurethane adhesive (PU. A thermoreactive phenolic resin was added to one of the polychloroprene adhesive formulations (PCP30R. This tackifier resin favors chlorination of the adhesive and reinforces the interface between the chlorinated adhesive and the chlorinated rubber surface. Besides, PCP30R adhesive does not need adhesive reactivation and considerable high T-peel strength value (5.7±0.3 kN/m was obtained. Elimination of the reactivation process implies a considerable improvement of the manufacturing process in the footwear industry.

  7. Reduced Efficiency of Chlorine Disinfection of Naegleria fowleri in a Drinking Water Distribution Biofilm.

    Science.gov (United States)

    Miller, Haylea C; Wylie, Jason; Dejean, Guillaume; Kaksonen, Anna H; Sutton, David; Braun, Kalan; Puzon, Geoffrey J

    2015-09-15

    Naegleria fowleri associated with biofilm and biological demand water (organic matter suspended in water that consumes disinfectants) sourced from operational drinking water distribution systems (DWDSs) had significantly increased resistance to chlorine disinfection. N. fowleri survived intermittent chlorine dosing of 0.6 mg/L for 7 days in a mixed biofilm from field and laboratory-cultured Escherichia coli strains. However, N. fowleri associated with an attached drinking water distribution biofilm survived more than 30 times (20 mg/L for 3 h) the recommended concentration of chlorine for drinking water. N. fowleri showed considerably more resistance to chlorine when associated with a real field biofilm compared to the mixed laboratory biofilm. This increased resistance is likely due to not only the consumption of disinfectants by the biofilm and the reduced disinfectant penetration into the biofilm but also the composition and microbial community of the biofilm itself. The increased diversity of the field biofilm community likely increased N. fowleri's resistance to chlorine disinfection compared to that of the laboratory-cultured biofilm. Previous research has been conducted in only laboratory scale models of DWDSs and laboratory-cultured biofilms. To the best of our knowledge, this is the first study demonstrating how N. fowleri can persist in a field drinking water distribution biofilm despite chlorination.

  8. Production of hydrogen by Clostridium species in the presence of chlorinated solvents.

    Science.gov (United States)

    Bowman, Kimberly S; Rainey, Fred A; Moe, William M

    2009-01-01

    Although anaerobic bioremediation of chlorinated organic contaminants in the environment often requires exogenous supply of hydrogen as an electron donor, little is known about the ability of hydrogen-producing bacteria to grow in the presence of chlorinated solvents. In this study, 18 Clostridium strains including nine uncharacterized isolates originating from chlorinated solvent contaminated groundwater were tested to determine their ability to fermentatively produce hydrogen in the presence of three common chlorinated aliphatic groundwater contaminants: 1,2-dichloroethane (DCA), 1,1,2-trichloroethane (TCA), and tetrachloroethene (PCE). All strains produced hydrogen in the presence of at least 7.4 mM DCA, 2.4 mM TCA, and 0.31 mM PCE. Some strains produced hydrogen in media containing concentrations as high as 29.7 mM DCA, 9.8 mM TCA, and 1.1 mM PCE. None of the strains biotransformed chlorinated solvents under the conditions tested. Results demonstrate that many Clostridium species are chlorinated solvent tolerant, producing hydrogen even in the presence of high concentrations of DCA, TCA, and PCE. These findings have important implications for bioremediation of contaminated soil and groundwater.

  9. Industrial metabolism of chlorine: a case study of a chlor-alkali industrial chain.

    Science.gov (United States)

    Han, Feng; Li, Wenfeng; Yu, Fei; Cui, Zhaojie

    2014-05-01

    Substance flow analysis (SFA) is applied to a case study of chlorine metabolism in a chlor-alkali industrial chain. A chain-level SFA model is constructed, and eight indices are proposed to analyze and evaluate the metabolic status of elemental chlorine. The primary objectives of this study are to identify low-efficiency links in production processes and to find ways to improve the operational performance of the industrial chain. Five-year in-depth data collection and analysis revealed that system production efficiency and source efficiency continued increasing since 2008, i.e., when the chain was first formed, at average annual growth rates of 21.01 % and 1.01 %, respectively. In 2011, 64.15 % of the total chlorine input was transformed into final products. That is, as high as 98.50 % of the chlorine inputs were utilized when other by-products were counted. Chlorine loss occurred mostly in the form of chloride ions in wastewater, and the system loss rate was 0.54 %. The metabolic efficiency of chlorine in this case was high, and the chain system had minimal impact on the environment. However, from the perspectives of processing depth and economic output, the case study of a chlor-alkali industrial chain still requires expansion.

  10. Effects of Chlorine Stress on Pseudomonas aeruginosa Biofilm and Analysis of Related Gene Expressions.

    Science.gov (United States)

    Kekeç, Özge; Gökalsın, Barış; Karaltı, İskender; Kayhan, Figen Esin; Sesal, Nüzhet Cenk

    2016-08-01

    Chlorine is deployed worldwide to clean waters and prevent water-originated illnesses. However, chlorine has a limited disinfection capacity against biofilms. Microorganisms form biofilms to protect themselves from biological threats such as disinfectant chemicals. Pseudomonas aeruginosa is an opportunistic pathogen and its biofilm form attaches to surfaces, living buried into exopolysaccharides, can be present in all watery environments including tap water and drinking water. This research aimed to study the biofilm trigger mechanism of the opportunistic pathogen P. aeruginosa PAO1 strain, which is known to form biofilm in water supply systems and human body, under chlorine stress levels. In addition to biofilm staining, certain genes that are relevant to the stress condition were selected for gene expression analysis. The bacteria cultures were grown under chlorine stress with concentrations of 0.5, 0.7 and 1 mg/l. Six gene regions were determined related to biofilm and stress response: rpoS, bifA, migA, katB, soxR, and algC. Biofilm formation was analyzed by basic fuchsin staining, and gene expressions were quantified by quantitative real-time PCR. According to the results, highest biofilm production was observed in P. aeruginosa PAO1 wild strain under no stress conditions. Higher biofilm amounts were observed for bacteria under 0.5 and 0.7 mg/l chlorine stress compared to 1 mg/l chlorine stress.

  11. Differential toxicity of drinking water disinfected with combinations of ultraviolet radiation and chlorine.

    Science.gov (United States)

    Plewa, Michael J; Wagner, Elizabeth D; Metz, Deborah H; Kashinkunti, Ramesh; Jamriska, Katherine J; Meyer, Maria

    2012-07-17

    Alternative technologies to disinfect drinking water such as ultraviolet (UV) disinfection are becoming more widespread. The benefits of UV disinfection include reduced risk of microbial pathogens such as Cryptosporidium and reduced production of regulated drinking water disinfection byproducts (DBPs). The objective of this research was to determine if mammalian cell cytotoxicity and genotoxicity varied in response to different chlorination protocols with and without polychromatic medium pressure UV (MPUV) and monochromatic low pressure UV (LPUV) disinfection technologies. The specific aims were to analyze the mammalian cell cytotoxicity and genotoxicity of concentrated organic fractions from source water before and after chlorination and to determine the cytotoxicity and genotoxicity of the concentrated organic fractions from water samples treated with UV alone or UV before or after chlorination. Exposure of granular activated carbon-filtered Ohio River water to UV alone resulted in the lowest levels of mammalian cell cytotoxicity and genotoxicity. With combinations of UV and chlorine, the lowest levels of cytotoxicity and genotoxicity were observed with MPUV radiation. The best combined UV plus chlorine methodology that generated the lowest cytotoxicity and genotoxicity employed chlorination first followed by MPUV radiation. These data may prove important in the development of multibarrier methods of pathogen inactivation of drinking water, while limiting unintended toxic consequences.

  12. Chlorination of oxybenzone: Kinetics, transformation, disinfection byproducts formation, and genotoxicity changes.

    Science.gov (United States)

    Zhang, Shujuan; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F

    2016-07-01

    UV filters are a kind of emerging contaminant, and their transformation behavior in water treatment processes has aroused great concern. In particular, toxic products might be produced during reaction with disinfectants during the disinfection process. As one of the most widely used UV filters, oxybenzone has received significant attention, because its transformation and toxicity changes during chlorine oxidation are a concern. In our study, the reaction between oxybenzone and chlorine followed pseudo-first-order and second-order kinetics. Three transformation products were detected by LC-MS/MS, and the stability of products followed the order of tri-chloro-methoxyphenoyl > di-chlorinated oxybenzone > mono-chlorinated oxybenzone. Disinfection byproducts (DBPs) including chloroform, trichloroacetic acid, dichloroacetic acid and chloral hydrate were quickly formed, and increased at a slower rate until their concentrations remained constant. The maximum DBP/oxybenzone molar yields for the four compounds were 12.02%, 6.28%, 0.90% and 0.23%, respectively. SOS/umu genotoxicity test indicated that genotoxicity was highly elevated after chlorination, and genotoxicity showed a significantly positive correlation with the response of tri-chloro-methoxyphenoyl. Our results indicated that more genotoxic transformation products were produced in spite of the elimination of oxybenzone, posing potential threats to drinking water safety. This study shed light on the formation of DBPs and toxicity changes during the chlorination process of oxybenzone.

  13. An electrospray ionization-tandem mass spectrometry method for identifying chlorinated drinking water disinfection byproducts.

    Science.gov (United States)

    Zhang, Xiangru; Minear, Roger A; Guo, Yingbo; Hwang, Cordelia J; Barrett, Sylvia E; Ikeda, Kazuhiro; Shimizu, Yoshihisa; Matsui, Saburo

    2004-11-01

    Identification of chlorinated drinking water disinfection byproducts (DBPs) was investigated by using electrospray ionization-mass spectrometry/mass spectrometry (ESI-MS/MS). Chlorine-containing compounds were found to form chloride ion fragments by MS/MS, which can be used as a 'fingerprint' for chlorinated DBPs. Instrumental parameters that affect the formation of chloride ions by ESI-MS/MS were examined, and appropriate conditions for use in finding specific structural information were evaluated. The results show that maximizing the formation of chloride ions by MS/MS required a relatively high collision energy and collision gas pressure; also, limiting the scan range to m/z 30-40 allowed improved sensitivity for detection; but obtaining structural information required the use of lower collision energies. The conditions obtained were demonstrated to be effective in identifying chlorinated DBPs in a standard sample with relatively low concentrations of each component and in a chlorinated humic substance sample. Sample pretreatment techniques including ultrafiltration and size exclusion chromatography appeared to be helpful for identifying highly polar or high molecular weight chlorine-containing DBPs by ESI-MS/MS.

  14. A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R.; Hunter, C.; Werth, D.; Chen, K.; Whiteside, M.; Mazzola, C.

    2011-05-10

    A train derailment occurred in Graniteville, South Carolina during the early morning of January 6, 2005, and resulted in the release of a large amount of cryogenic pressurized liquid chlorine to the environment in a short time period. A comprehensive evaluation of the transport and fate of the released chlorine was performed, accounting for dilution, diffusion, transport and deposition into the local environment. This involved the characterization of a three-phased chlorine release, a detailed determination of local atmospheric mechanisms acting on the released chlorine, the establishment of atmospheric-hydrological physical exchange mechanisms, and aquatic dilution and mixing. This presentation will provide an overview of the models used in determining the total air-to-water mass transfer estimated to have occurred as a result of the roughly 60 tons of chlorine released into the atmosphere from the train derailment. The assumptions used in the modeling effort will be addressed, along with a comparison with available observational data to validate the model results. Overall, model-estimated chlorine concentrations in the airborne plume compare well with human and animal exposure data collected in the days after the derailment.

  15. Drinking water biofilm cohesiveness changes under chlorination or hydrodynamic stress.

    Science.gov (United States)

    Mathieu, L; Bertrand, I; Abe, Y; Angel, E; Block, J C; Skali-Lami, S; Francius, G

    2014-05-15

    Attempts at removal of drinking water biofilms rely on various preventive and curative strategies such as nutrient reduction in drinking water, disinfection or water flushing, which have demonstrated limited efficiency. The main reason for these failures is the cohesiveness of the biofilm driven by the physico-chemical properties of its exopolymeric matrix (EPS). Effective cleaning procedures should break up the matrix and/or change the elastic properties of bacterial biofilms. The aim of this study was to evaluate the change in the cohesive strength of two-month-old drinking water biofilms under increasing hydrodynamic shear stress τw (from ∼0.2 to ∼10 Pa) and shock chlorination (applied concentration at T0: 10 mg Cl2/L; 60 min contact time). Biofilm erosion (cell loss per unit surface area) and cohesiveness (changes in the detachment shear stress and cluster volumes measured by atomic force microscopy (AFM)) were studied. When rapidly increasing the hydrodynamic constraint, biofilm removal was found to be dependent on a dual process of erosion and coalescence of the biofilm clusters. Indeed, 56% of the biofilm cells were removed with, concomitantly, a decrease in the number of the 50-300 μm(3) clusters and an increase in the number of the smaller (i.e., 600 μm(3)) ones. Moreover, AFM evidenced the strengthening of the biofilm structure along with the doubling of the number of contact points, NC, per cluster volume unit following the hydrodynamic disturbance. This suggests that the compactness of the biofilm exopolymers increases with hydrodynamic stress. Shock chlorination removed cells (-75%) from the biofilm while reducing the volume of biofilm clusters. Oxidation stress resulted in a decrease in the cohesive strength profile of the remaining drinking water biofilms linked to a reduction in the number of contact points within the biofilm network structure in particular for the largest biofilm cluster volumes (>200 μm(3)). Changes in the cohesive

  16. Fast Fourier Transform Chlorine Nuclear Quadrupole Resonance Spectroscopy.

    Science.gov (United States)

    D'Iorio, Marie

    A nuclear quadrupole resonance spectrometer operating in the frequency range 1-40 MHz was updated for fast Fourier transform spectroscopy and coupled to a Nicolet 1180 computer and data acquisition system. It was used with a low temperature cryostat for studies shown down to liquid helium temperature and with a high pressure/low temperature system for studies down to liquid nitrogen temperature and up to six kilobars. The study of the ('35)Cl NQR spectrum of K(,2)OsCl(,6) at 298 K and 77 K revealed the presence of a satellite associated with the nearest neighbour chlorines to H('+) ion impurities located at vacant octahedral sties. This result is in agreement with the predictions of a point charge model calculation. A residence time for the H('+) ion was deduced and is consistent with the result obtained from dielectric measurements. A detailed study of the ('35)Cl NQR frequency in K(,2)ReCl(,6) was performed in the temperature range 85 - 130K where two structural phase transitions occur, and at pressures from 1 to 2643 bars. A number of unusual features were revealed and discussed as the possible signature of incommensurate behavior. The primary effect of the pressure was to alter the temperatures at which the phase transitions occurred. Contrary to the behavior expected, the transition temperature for the antiferrorotative transition has a negative pressure coefficient. The spin-lattice and spin-spin relaxation times for the ('35)Cl and ('37)Cl isotopes of the one dimensional XY system, PrCl(,3), were measured at 4.2K. The spin-lattice relaxation is exponential and dominated by magnetic dipole -dipole interactions. The spin-spin relaxation is non-exponential and dominated by electric quadrupolar interactions arising from the coupling of the electric dipole moment at the praseodymium site and the quadrupole moment of the chlorine ion. The temperature dependence of the spin-spin relaxation time was investigated. At 17.4 K both magnetic dipolar and electric

  17. A healthy, female chimera with 46,XX/46,XY karyotype.

    NARCIS (Netherlands)

    Binkhorst, M.; Leeuw, N. de; Otten, B.J.

    2009-01-01

    We report a healthy and unambiguously female newborn, whose phenotypic sex contradicted the expected male sex based on previously performed prenatal cytogenetic analysis. Both 46,XX and 46,XY cells were detected in a villus sample, the former having been attributed to maternal cell contamination. Po

  18. VARIATIONS IN ISOTOPIC COMPOSITIONS OF CHLORINE IN EVAPORATION-CONTROLLED SALT LAKE BRINES OF QAIDAM BASIN,CHINA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs2Cl+ ion by thermal ionization mass spectrometry. The results showed that variation in δ37Cl values in these evaporation-controlled brines are attributable to evaporation of brine accompanied by the deposition of saline minerals. The isotopic fractionation of chlorine between the deposited saline mineral and the co-existing brine caused the variation of δ37Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of 37Cl in the solid phase relative to 35Cl. The reverse isotopic fractionation of chlorine in which 35Cl is enriched in the solid phase, was observed to some extent during quick deposition under laboratory conditions as well as in nature. The mechanism of isotopic fractionation of chlorine during evaporation deposition was studied.

  19. Removal of hexenuronic acid by xylanase to reduce adsorbable organic halides formation in chlorine dioxide bleaching of bagasse pulp.

    Science.gov (United States)

    Nie, Shuangxi; Wang, Shuangfei; Qin, Chengrong; Yao, Shuangquan; Ebonka, Johnbull Friday; Song, Xueping; Li, Kecheng

    2015-11-01

    Xylanase-aided chlorine dioxide bleaching of bagasse pulp was investigated. The pulp was pretreated with xylanase and followed a chlorine dioxide bleaching stage. The ATR-FTIR and XPS were employed to determine the surface chemistry of the control pulp, xylanase treated and chlorine dioxide treated pulps. The hexenuronic acid (HexA) could obviously be reduced after xylanase pretreatment, and the adsorbable organic halides (AOX) were reduced after chlorine dioxide bleaching. Compared to the control pulp, AOX could be reduced by 21.4-26.6% with xylanase treatment. Chlorine dioxide demand could be reduced by 12.5-22% to achieve the same brightness. The ATR-FTIR and XPS results showed that lignin and hemicellulose (mainly HexA) were the main source for AOX formation. Xylanase pretreatment could remove HexA and expose more lignin, which decreased the chlorine dioxide demand and thus reduced formation of AOX.

  20. Oxidation of chlorinated olefins by Escherichia coli transformed with dimethyl sulfide monooxygenase genes or cumene dioxygenase genes.

    Science.gov (United States)

    Takami, Wako; Yoshida, Takako; Nojiri, Hideaki; Yamane, Hisakazu; Omori, Toshio

    1999-04-01

    In the present work, it was shown that the dimethyl sulfide (DMS) monooxygenase and the cumene dioxygenase catalyzed oxidation of various chlorinated ethenes, propenes, and butenes. The specific activities of these oxygenases were determined for C(2) to C(4) chlorinated olefins, and the oxidation rates ranged from 0.19 to 4.18 nmol.min(-1).mg(-1) of dry cells by the DMS monooxygenase and from 0.19 to 1.29 nmol.min(-1).mg(-1) of dry cells by the cumene dioxygenase. The oxidation products were identified by gas chromatography-mass spectrometry. Most chlorinated olefins were monooxygenated by the DMS monooxygenase to yield chlorinated epoxides. In the case of the cumene dioxygenase, the substrates lacking any chlorine atom on double-bond carbon atoms were dioxygenated, and those with chlorine atoms attaching to double-bond carbon atoms were monooxygenated to yield allyl alcohols.

  1. Ecogenomics of microbial communities in bioremediation of chlorinated contaminated sites

    Directory of Open Access Journals (Sweden)

    Farai eMaphosa

    2012-10-01

    Full Text Available Organohalide compounds such as chloroethenes, chloroethanes and polychlorinated benzenes are among the most significant pollutants in the world. These compounds are often found in contamination plumes with other pollutants such as solvents, pesticides and petroleum derivatives. Microbial bioremediation of contaminated sites, has become commonplace whereby key processes involved in bioremediation include anaerobic degradation and transformation of these organohalides by organohalide respiring bacteria and also via hydrolytic, oxygenic and reductive mechanisms by aerobic bacteria. Microbial ecogenomics has enabled us to not only study the microbiology involved in these complex processes but also develop tools to better monitor and assess these sites during bioremediation. Microbial ecogenomics have capitalized on recent advances in high-throughput and -output genomics technologies in combination with microbial physiology studies to address these complex bioremediation problems at a system level. Advances in environmental metagenomics, transcriptomics and proteomics have provided insights into key genes and their regulation in the environment. They have also given us clues into microbial community structures, dynamics and functions at contaminated sites. These techniques have not only aided us in understanding the lifestyles of common organohalide respirers, for example Dehalococcoides, Dehalobacter and Desulfitobacterium, but also provided insights into novel and yet uncultured microorganisms found in organohalide respiring consortia. In this paper we look at how ecogenomic studies have aided us to understand the microbial structures and functions in response to environmental stimuli such as the presence of chlorinated pollutants.

  2. Chlorine dioxide-facilitated oxidation of the azo dye amaranth.

    Science.gov (United States)

    Nadupalli, S; Koorbanally, N; Jonnalagadda, S B

    2011-10-27

    The oxidation reaction of amaranth (trisodium 2-hydroxy-1-(4-sulfonato-1-naphthylazo)naphthalene-3,6-disulfonate or AM(-)) by chlorine dioxide (ClO(2)) in aqueous conditions was investigated in detail. The major reaction products immediately after decolorization of AM(-) were 1,2-naphthoquinone disulfonate sodium salt and 1,4-napthalenedione. The reaction had first-order dependence on both AM(-) and ClO(2). The rate-limiting step involved the reaction between AM(-) and OH(-) ions. The role of hydroxide ion as a catalyst was established. The second-order rate constant increased with pH, from (19.8 ± 0.9) M(-1) s(-1) at pH 7.0, (97.1 ± 2.3) M(-1) s(-1) at pH 8.0 to (132.5 ± 2.8) M(-1) s(-1) at pH 9.0. In the pH range of 6.0-7.5, the catalytic constant for OH(-) ion was 4.0 × 10(9) M(-2) s(-1). The energy and entropy of activation values for the reaction were 50.0 kJ mol(-1) and -658.7 J K(-1) mol(-1), respectively. A probable reaction mechanism was elucidated and was validated by simulations.

  3. Solidification of sediment contaminated with volatile chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, E.J. [Anchor QEA LLC, Portland, OR (United States)

    2010-07-01

    A series of bench-scale treatability tests were used to evaluate the effectiveness of various solidification reagents in treating sediments contaminated with high concentrations of chlorinated hydrocarbons. The effectiveness of Portland cement, cement kiln dust, lime kiln dust, fly ash, and a combination of silica and lime were was assessed relative to their ability to reduce the leaching of contaminants, increase the strength of the contaminated sediment, and reduce the hydraulic conductivity of the sediments. The aim of the study was to develop a design for treating sediments in a stagnant water body located on the grounds of an industrial facility. The sediments were predominantly fine-grained and high in organic content. Preliminary tests identified Portland cement and the silica and lime mixture as achieving the desired strength and resistance to leaching. The solidification reagents were used to solidify more than 11,000 cubic yards of sediment with a mixture of 2 fly ashes. The full-scale solidification project surpassed the required standards for strength and permeability. 10 refs., 4 tabs., 3 figs.

  4. Core-level excitation and fragmentation of chlorine dioxide

    Science.gov (United States)

    Flesch, R.; Plenge, J.; Rühl, E.

    2006-03-01

    Inner-shell excitation and fragmentation of chlorine dioxide (OClO) in the Cl 2p- and O 1s-excitation regime is reported. The electronic structure of the element-selectively excited radical is studied by X-ray absorption and total cation yields. A comparison of both approaches allows us to estimate the absolute photoionization cross-section and the ionization yield near the Cl 2p- and O 1s-absorption edges. The latter quantity is characteristically enhanced in core-ionization continua. We observe below both core-absorption edges intense core-to-valence-transitions. These are assigned in comparison with related work on core-excited sulfur dioxide. These results give clear evidence that the highest molecular orbital of OClO is half-filled. High-resolution spectra recorded in the Cl 2p-regime show evidence for Rydberg transitions. The extrapolation of the term values of the low-lying Rydberg states allows us to derive the Cl 2p-ionization energy of OClO. Fragmentation of core-excited OClO is reported. Photoelectron-photoion-coincidence (PEPICO) spectra are recorded, indicating that singly and doubly charged fragments are formed. Fission of the doubly and multiply charged OClO leads to singly charged fragments. These are measured by photoion-photoion-coincidence (PIPICO) spectra, where characteristic changes in intensity of the fission channels in the Cl 2p- and O 1s-continuum are observed.

  5. Very Low Energy Electron Scattering from Ozone and Chlorine Dioxide

    Science.gov (United States)

    Gulley, R. J.; Field, T. A.; Steer, W. A.; Mason, N. J.; Ziesel, J. P.; Lunt, S. L.; Field, D.

    1998-10-01

    Total cross-sections are reported for the scattering of electrons from ozone (O_3) and chlorine dioxide (OClO) for energies in the range of 9 meV to 10 eV. The measurements were made in transmission experiments using a synchrotron photoionization apparatus with an energy resolution in the incident electron beam of ~ 3.5 meV (FWHM). The cross section for O3 shows strong rotational scattering at low energy, through the presence of the permanent dipole moment of O_3. Superposed on this strong scattering signal, there is evidence of a weak structure around 50 meV associated with dissociative attachment. A shape resonance, known from earlier work at ~ 4 meV, is also observed. Electron scattering from OClO is dominated by rotationally inelastic scattering decreasing from a peak at essentially zero eV to an energy of 40 meV, where p-wave attachment becomes more important, peaking at 50--60 meV and extending to several hundred meV.

  6. Etching Rate of Silicon Dioxide Using Chlorine Trifluoride Gas

    Science.gov (United States)

    Miura, Yutaka; Kasahara, Yu; Habuka, Hitoshi; Takechi, Naoto; Fukae, Katsuya

    2009-02-01

    The etching rate behavior of silicon dioxide (SiO2, fused silica) using chlorine trifluoride (ClF3) gas is studied at substrate temperatures between 573 and 1273 K at atmospheric pressure in a horizontal cold-wall reactor. The etching rate increases with the ClF3 gas concentration, and the overall reaction is recognized to be of the first order. The change of the etching rate with increasing substrate temperature is nonlinear, and the etching rate tends to approach a constant value at temperatures exceeding 1173 K. The overall rate constant is estimated by numerical calculation, taking into account the transport phenomena in the reactor, including the chemical reaction at the substrate surface. The activation energy obtained in this study is 45.8 kJ mol-1, and the rate constant is consistent with the measured etching rate behavior. A reactor system in which there is minimum etching of the fused silica chamber by ClF3 gas can be achieved using an IR lamp heating unit and a chamber cooling unit to maintain a sufficiently low temperature of the chamber wall.

  7. Imaging the dynamics of chlorine atom reactions with alkenes

    Science.gov (United States)

    Estillore, Armando D.; Visger, Laura M.; Suits, Arthur G.

    2010-08-01

    We report a study of chlorine atom reactions with a series of target monounsaturated alkene molecules: 1-pentene, 1-hexene, 2-hexene, and cyclohexene. These reactions were studied using crossed-beam dc slice ion imaging at collision energies of 4 and 7 kcal/mol. Images of the reactively scattered alkenyl radical products were obtained via single photon ionization at 157 nm. The angular distributions at low collision energy are largely isotropic, suggesting the formation of a complex that has a lifetime comparable to or longer than its rotational period, followed by HCl elimination. At high collision energy, the distributions show a sharp forward peak superimposed on the isotropic component accounting for ˜13% of the product flux. The translational energy distributions peak near zero for the backscattered product, in sharp contrast to the results for alkanes. In the forward direction, the translational energy distributions change dramatically with collision energy. At the high collision energy, a sharp forward peak at ˜80% of the collision energy appears, quite reminiscent of results of our recent study of Cl+pentane reactions. The scattering distributions for all target molecules are similar, suggesting similarity of the reaction dynamics among these molecules. Ab initio calculations of the energetics and ionization energies for the various product channels were performed at the CBS-QB3 level to aid in interpreting the results.

  8. Degradation of microcystin-RR in water by chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    JI Ying; HUANG Jun-li; FU Jiao; WU Ming-song; CUI Chong-wei

    2008-01-01

    Due to the potent hepatotoxicity and tumor-promoting activity of microcystins, a successful removal of these toxins during drinking water treatment processes is of increasing concern. The oxidation kinetics of MC-RR by chlorine dioxide (C1O2)was studied with HPLC and characterization of the reacdon products was performed with UV-spectrometry, TOC and LC-MS. Our experimental results show that the oxidation process is a second order overall and a first order with respect to C1O2 and MC-RR.The activation energy of MC-RR degradation by C1O2 is 53.07 kJ/mol. The rate constant k of the action can be increased by increasing temperature and decreasing pH value and ranged from 6. 11x102 L/(mol.min) to 5.29x 102 L/(mol-min) at pH from 3.44 to 10.41 at 10 ℃. Reaction products were determined to be organic and volatile, because they could be almost removed from aqueous solution by heating for 15 min at 60 ℃. In addition, the main oxidation products have m/z values of 1072 and are identified as dihydroxy isomers of MC-RR.

  9. Protein chlorination in neutrophil phagosomes and correlation with bacterial killing.

    Science.gov (United States)

    Green, Jessie N; Kettle, Anthony J; Winterbourn, Christine C

    2014-12-01

    Neutrophils ingest and kill bacteria within phagocytic vacuoles. We investigated where they produce hypochlorous acid (HOCl) following phagocytosis by measuring conversion of protein tyrosine residues to 3-chlorotyrosine. We also examined how varying chloride availability affects the relationship between HOCl formation in the phagosome and bacterial killing. Phagosomal proteins, isolated following ingestion of opsonized magnetic beads, contained 11.4 Cl-Tyr per thousand tyrosine residues. This was 12 times higher than the level in proteins from the rest of the neutrophil and ~6 times higher than previously recorded for protein from ingested bacteria. These results indicate that HOCl production is largely localized to the phagosomes and a substantial proportion reacts with phagosomal protein before reaching the microbe. This will in part detoxify the oxidant but should also form chloramines which could contribute to the killing mechanism. Neutrophils were either suspended in chloride-free gluconate buffer or pretreated with formyl-Met-Leu-Phe, a procedure that has been reported to deplete intracellular chloride. These treatments, alone or in combination, decreased both chlorination in phagosomes and killing of Staphylococcus aureus by up to 50%. There was a strong positive correlation between the two effects. Killing was predominantly oxidant and myeloperoxidase dependent (88% inhibition by diphenylene iodonium and 78% by azide). These results imply that lowering the chloride concentration limits HOCl production and oxidative killing. They support a role for HOCl generation, rather than an alternative myeloperoxidase activity, in the killing process.

  10. Degradation of chlorinated phenols by nanoscale zero-valent iron

    Institute of Scientific and Technical Information of China (English)

    Rong CHENG; Jianlong WANG; Weixian ZHANG

    2008-01-01

    Chlorophenols (CPs), as important contami-nants in groundwater, are toxic and difficult to biode-grade. Recently nanoscale zero-valent iron received a great deal of attention because of its excellent performance in treating recalcitrant compounds. In this study, nanoscale zero-valent iron particles were prepared using chemical reduction, and the reductive transformations of three kinds of chlorinated phenols (2-CP, 3-CP, and 4-CP) by nanoscale zero-valent iron under different conditions were investigated. The transformation process of the CPs was shown to be dechlorination first, then cleavage of the benzene ring. The removal efficiency of the CPs varied as follows: 2-CP3-CP4-CP. The reactivity of CPs was associated with their energy of lowest unoccupied molecular orbit (ELUMO). With the increase in initial concentrations of CPs, removal efficiency decreased a little. But the quantities of CPs reduced increased evidently. Temperature had influence on not only the removal efficiency, but also the transformation pathway. At higher temperatures, dechlorination occurred prior to benzene ring cleavage. At lower temperatures, however, the oxidation product was formed more easily.

  11. Reactive chlorine chemistry in the boundary layer of coastal Antarctica

    Science.gov (United States)

    Zielcke, Johannes; Poehler, Denis; Friess, Udo; Hay, Tim; Eger, Philipp; Kreher, Karin; Platt, Ulrich

    2015-04-01

    A unique feature of the polar troposphere is the strong impact of halogen photochemistry, in which reactive halogen species are responsible for ozone depletion as well as the oxidation of elemental mercury and dimethyl sulphide. The source, however, as well as release and recycling mechanisms of these halogen species - for some species even abundances - are far from being completely known, especially of chlorine and iodine compounds. Here we present active long-path differential optical absorption spectroscopy (LP-DOAS) measurements conducted during austral spring 2012 at Ross Island, Antarctica, observing several species (BrO, O3, NO2, IO, ClO, OBrO, OClO, OIO, I2, CHOCHO, HCHO, HONO). For the first time, ClO was detected and quantified in the marine boundary layer of coastal Antarctica, with typical mixing ratios around 20 pptv and maxima around 50 pptv. Meteorological controls on the mixing ratio of ClO as well as the interplay with other halogen compounds will be discussed, such as the lack of observed OClO (< 1 pptv). The results seem to reflect previously in chamber studies observed dependences on ozone levels and solar irradiance.

  12. Uptake, turnover and distribution of chlorinated fatty acids in aquatic biota

    Energy Technology Data Exchange (ETDEWEB)

    Bjoern, Helena

    1999-09-01

    Chlorinated fatty acids (CIFAs) are the major contributors of extractable, organically bound chlorine in fish lipids. A known anthropogenic source of CIFAs is chlorine bleached pulp production. Additional anthropogenic sources may exist, e.g., chlorine-containing discharge from industrial and household waste and they may also occur naturally. CIFAs have a wide geographic distribution. They have, for instance, been identified in fish both from Alaskan and Scandinavian waters. In toxicological studies of CIFAs, the most pronounced effects have been found in reproductive related processes. CIFAs have also been shown to disrupt cell membrane functions. The present study was carried out to further characterise the ecotoxicological properties of CIFAs and their presence in biota. To investigate the biological stability of CIFAs, two experiments were carried out using radiolabelled chlorinated and non-chlorinated fatty acids. In both experiments, CIFAs were taken up from food by fish and assimilated to lipids. From the first experiment it was concluded that the chlorinated fatty acid investigated was turned over in the fish to a lower degree than the non-chlorinated analogue. In the second experiment, the transfer of a chlorinated fatty acid was followed over several trophic levels and the chlorinated fatty acid was transferred to the highest trophic level. In samples with differing loads of persistent organic pollutants (POPs) from both fish and marine mammals, high concentrations and diversity of CIFAs were detected. This was also observed in samples with low POP concentration. Chlorohydroxy fatty acids made up a considerable portion of the CIFAs in certain samples, both from limnic fish and marine mammals. CIFAs in fish were found to be bound in complex lipids such as triacylglycerols (storage lipids) and phospholipids, as well as in acyl sterols (membrane lipids). In the marine mammals investigated, high concentrations of CIFAs were mainly bound in phospholipids. If

  13. Photochemical ozone and nitric oxide formation in air-nitrogen dioxide mixtures containing sulfur dioxide or chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, J.S.; Springer, G.S.; Stedman, D.H.

    1980-01-01

    The effects of sulfur dioxide and chlorine on ozone and nitric oxide concentrations in nitrogen dioxide-air mixtures were studied. The presence of 0-10 ppM SO/sub 2/ produced no change in the air mixture. Addition of 1-15 ppm chlorine increased the ozone concentration in the air mixture. A reaction model describing the interactions of chlorine and NO/sub 2/ is presented. (1 diagram, 6 graphs, 30 references, 3 tables)

  14. A theoretical study of the interference from chlorine in the oxidative coulometric method for trace determination of sulphur in hydrocarbons.

    Science.gov (United States)

    Cedergren, A

    1975-12-01

    A theoretical investigation has been made of the interference from chlorine in the oxidative coulometric method for trace sulphur determinations. A computer program (SOLGAS), based on the free-energy minimization principle, has been used to predict equilibrium compositions of the products resulting from combustion of a hydrocarbon sample containing sulphur and chlorine. The theoretical possibilities of overcoming the interference from chlorine and maintaining a high recovery of sulphur are described.

  15. Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Amy J Pickering

    Full Text Available The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab, safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

  16. Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial.

    Science.gov (United States)

    Pickering, Amy J; Crider, Yoshika; Amin, Nuhu; Bauza, Valerie; Unicomb, Leanne; Davis, Jennifer; Luby, Stephen P

    2015-01-01

    The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

  17. Stable Chlorine Isotopes and Elemental Chlorine by Thermal Ionization Mass Spectrometry and Ion Chromatography; Martian Meteorites, Carbonaceous Chondrites and Standard Rocks

    Science.gov (United States)

    Nakamura, N.; Nyquist, L. E.; Reese, Y.; Shih, C.-Y.; Fujitani, T.; Okano, O.

    2011-01-01

    Recently significantly large mass fractionation of stable chlorine isotopes has been reported for terrestrial and lunar samples [1,2]. In addition, in view of possible early solar system processes [3] and also potential perchlorate-related fluid/microbial activities on the Martian surface [4,5], a large chlorine isotopic fractionation might be expected for some types of planetary materials. Due to analytical difficulties of isotopic and elemental analyses, however, current chlorine analyses for planetary materials are controversial among different laboratories, particularly between IRMS (gas source mass spectrometry) and TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1,6,7] for isotopic analyses, as well as between those doing pyrohydrolysis and other groups [i.e. 6,8]. Additional careful investigations of Cl isotope and elemental abundances are required to confirm real chlorine isotope and elemental variations for planetary materials. We have developed a TIMS technique combined with HF-leaching/ion chromatography at NASA JSC that is applicable to analysis of small amounts of meteoritic and planetary materials. We present here results for several standard rocks and meteorites, including Martian meteorites.

  18. 45,X/46,XY mosaicism

    DEFF Research Database (Denmark)

    Lindhardt Johansen, Marie; Hagen, Casper P; Rajpert-De Meyts, Ewa;

    2012-01-01

    Most previous studies of 45,X/46,XY mosaicism are case reports or have described single aspects of the disease.......Most previous studies of 45,X/46,XY mosaicism are case reports or have described single aspects of the disease....

  19. Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia.

    Science.gov (United States)

    Abdallah, Pamela; Deborde, Marie; Dossier Berne, Florence; Karpel Vel Leitner, Nathalie

    2015-12-15

    The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

  20. Chlorine dioxide inactivation of Cryptosporidium parvum oocysts and bacterial spore indicators.

    Science.gov (United States)

    Chauret, C P; Radziminski, C Z; Lepuil, M; Creason, R; Andrews, R C

    2001-07-01

    Cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. Recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against Cryptosporidium oocysts. It is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. This study used both a most-probable-number-cell culture infectivity assay and in vitro excystation to evaluate chlorine dioxide inactivation kinetics in laboratory water at pH 8 and 21 degrees C. The two viability methods produced significantly different results (P < 0.05). Products of disinfectant concentration and contact time (Ct values) of 1,000 mg. min/liter were needed to inactivate approximately 0.5 log(10) and 2.0 log(10) units (99% inactivation) of C. parvum as measured by in vitro excystation and cell infectivity, respectively, suggesting that excystation is not an adequate viability assay. Purified oocysts originating from three different suppliers were evaluated and showed marked differences with respect to their resistance to inactivation when using chlorine dioxide. Ct values of 75, 550, and 1,000 mg. min/liter were required to achieve approximately 2.0 log(10) units of inactivation with oocysts from different sources. Finally, the study compared the relationship between easily measured indicators, including Bacillus subtilis (aerobic) spores and Clostridium sporogenes (anaerobic) spores, and C. parvum oocysts. The bacterial spores were found to be more sensitive to chlorine dioxide than C. parvum oocysts and therefore could not be used as direct indicators of C. parvum inactivation for this disinfectant. In conclusion, it is suggested that future studies address issues such as oocyst purification protocols and the genetic diversity of C. parvum, since these factors might affect oocyst disinfection sensitivity.

  1. Chlorine Dioxide Inactivation of Cryptosporidium parvum Oocysts and Bacterial Spore Indicators

    Science.gov (United States)

    Chauret, Christian P.; Radziminski, Chris Z.; Lepuil, Michael; Creason, Robin; Andrews, Robert C.

    2001-01-01

    Cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. Recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against Cryptosporidium oocysts. It is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. This study used both a most-probable-number–cell culture infectivity assay and in vitro excystation to evaluate chlorine dioxide inactivation kinetics in laboratory water at pH 8 and 21°C. The two viability methods produced significantly different results (P < 0.05). Products of disinfectant concentration and contact time (Ct values) of 1,000 mg · min/liter were needed to inactivate approximately 0.5 log10 and 2.0 log10 units (99% inactivation) of C. parvum as measured by in vitro excystation and cell infectivity, respectively, suggesting that excystation is not an adequate viability assay. Purified oocysts originating from three different suppliers were evaluated and showed marked differences with respect to their resistance to inactivation when using chlorine dioxide. Ct values of 75, 550, and 1,000 mg · min/liter were required to achieve approximately 2.0 log10 units of inactivation with oocysts from different sources. Finally, the study compared the relationship between easily measured indicators, including Bacillus subtilis (aerobic) spores and Clostridium sporogenes (anaerobic) spores, and C. parvum oocysts. The bacterial spores were found to be more sensitive to chlorine dioxide than C. parvum oocysts and therefore could not be used as direct indicators of C. parvum inactivation for this disinfectant. In conclusion, it is suggested that future studies address issues such as oocyst purification protocols and the genetic diversity of C. parvum, since these factors might affect oocyst disinfection sensitivity. PMID:11425712

  2. Disinfection of football protective equipment using chlorine dioxide produced by the ICA TriNova system

    Directory of Open Access Journals (Sweden)

    DuBois John D

    2009-09-01

    Full Text Available Abstract Backround Community-associated methicillin-resistant Staphylococcus aureus outbreaks have occurred in individuals engaged in athletic activities such as wrestling and football. Potential disease reduction interventions include the reduction or elimination of bacteria on common use items such as equipment. Chlorine dioxide has a long history of use as a disinfectant. The purpose of this investigation was to evaluate the ability of novel portable chlorine dioxide generation devices to eliminate bacteria contamination of helmets and pads used by individuals engaged in football. Methods In field studies, the number of bacteria associated with heavily used football helmets and shoulder pads was determined before and after overnight treatment with chlorine dioxide gas. Bacteria were recovered using cotton swabs and plated onto trypticase soy agar plates. In laboratory studies, Staphylococcus aureus was applied directly to pads. The penetration of bacteria into the pads was determined by inoculating agar plates with portions of the pads taken from the different layers of padding. The ability to eliminate bacteria on the pad surface and underlying foam layers after treatment with chlorine dioxide was also determined. Results Rates of recovery of bacteria after treatment clearly demonstrated that chlorine dioxide significantly (p 3 recoverable bacteria colonies before chlorine dioxide treatment and 1.3 × 102 recoverable colonies after treatment. In addition, the gas was capable of penetrating the mesh surface layer and killing bacteria in the underlying foam pad layers. Here, 7 × 103 to 4.5 × 103 laboratory applied S. aureus colonies were recovered from underlying layers before treatment and 0 colonies were present after treatment. Both naturally occurring bacteria and S. aureus were susceptible to the treatment process. Conclusion Results of this study have shown that chlorine dioxide can easily and safely be used to eliminate bacteria

  3. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection.

    Science.gov (United States)

    Chusaksri, Sarinma; Sutthivaiyakit, Somyote; Sedlak, David L; Sutthivaiyakit, Pakawadee

    2012-03-30

    Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3'-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25°C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M(-1)s(-1) for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

  4. Kinetics of aqueous chlorination of some pharmaceuticals and their elimination from water matrices.

    Science.gov (United States)

    Acero, Juan L; Benitez, F Javier; Real, Francisco J; Roldan, Gloria

    2010-07-01

    Apparent rate constants for the reactions of four selected pharmaceutical compounds (metoprolol, naproxen, amoxicillin, and phenacetin) with chlorine in ultra-pure (UP) water were determined as a function of the pH. It was found that amoxicillin (in the whole pH range 3-12), and naproxen (in the low pH range 2-4) presented high reaction rates, while naproxen (in the pH range 5-9), and phenacetin and metoprolol (in the pH range 2.5-12 for phenacetin, and 3-10 for metoprolol) followed intermediate and slow reaction rates. A mechanism is proposed for the chlorination reaction, which allowed the evaluation of the intrinsic rate constants for the elementary reactions of the ionized and un-ionized species of each selected pharmaceutical with chlorine. An excellent agreement is obtained between experimental and calculated rate constants by this mechanism.The elimination of these substances in several waters (a groundwater, a surface water from a public reservoir, and two effluents from municipal wastewater treatment plants) was also investigated at neutral pH. The efficiency of the chlorination process with respect to the pharmaceuticals elimination and the formation THMs was also established. It is generally observed that the increasing presence of organic and inorganic matter in the water matrices demand more oxidant agent (chlorine), and therefore, less chlorine is available for the oxidation of these compounds. Finally, half-life times and oxidant exposures (CT) required for the removal of 99% of the four pharmaceuticals are also evaluated. These parameters are useful for the establishment of safety chlorine doses in oxidation or disinfection stages of pharmaceuticals in treatment plants.

  5. Non-destructive analysis of chlorine in fly ash cement concrete

    Science.gov (United States)

    Naqvi, A. A.; Garwan, M. A.; Nagadi, M. M.; Maslehuddin, M.; Al-Amoudi, O. S. B.; Khateeb-ur-Rehman

    2009-08-01

    Preventive measures against reinforcement corrosion in concrete require increasing concrete density to prevent the diffusion of chloride ions to the steel surface. Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to concrete to increase its density. Monitoring the chloride concentration in concrete is required to assess the chances of reinforcement corrosion. In this study, FA was added to Portland cement concrete to increase its density. Prompt gamma neutron activation analysis (PGNAA) technique was utilized to analyze the concentration of chlorine in concrete. The chlorine concentration in the FA cement concrete was evaluated by determining the yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV gamma-rays of chlorine from the FA concrete specimen containing 0.4-3.5 wt% chlorine. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the calculated yield obtained through the Monte Carlo simulations. The Minimum Detectable Concentration (MDC) of chlorine in FA cement concrete was also calculated. The best value of MDC limit of chlorine in the FA cement concrete was found to be 0.022±0.007 and 0.038±0.017 wt% for 1.16 and 6.11 MeV prompt gamma-rays, respectively. Within the statistical uncertainty, the lower bound of MDC meets the maximum permissible limit of 0.03 wt% of chlorine in concrete set by American Concrete Institute Committee 318.

  6. Dioxin emissions from coal combustion in domestic stove: Formation in the chimney and coal chlorine content influence

    Directory of Open Access Journals (Sweden)

    Paradiz Bostjan

    2015-01-01

    Full Text Available Combustion experiments conducted in domestic stove burning hard coal demonstrated a predominant influence of the coal chlorine content on the PCDD/F emissions, together with a pronounced effect of the flue gas temperature. PCDD/F concentrations of over 100 ng TEQ/m3, three orders of magnitude higher than in a modern waste incinerator, were measured in the flue gases of a domestic stove when combusting high chlorine coal (0.31 %. The PCDD/F concentrations in the flue gases dropped below 0,5 ng TEQ/m3, when low chlorine coal (0.07 % was used. When low chlorine coal was impregnated with NaCl to obtain 0.38 % chlorine content, the emission of the PCDD/Fs increased by two orders of magnitude. Pronounced nonlinearity of the PCDD/F concentrations related to chlorine content in the coal was observed. The combustion of the high chlorine coal yielded PCDD/F concentrations in flue gases one order of magnitude lower in a fan cooled chimney when compared to an insulated one, thus indicating formation in the chimney. The influence of flue gas temperature on the PCDD/F emissions was less pronounced when burning low chlorine coal. The predominant pathway of the PCDD/F emissions is via flue gases, 99 % of the TEQ in the case of the high chlorine coal for insulated chimney.

  7. THE COMPATIBILITY OF BLENDS OF POLY(VINYL CHLORIDE) OR CHLORINATED POLY(VINYL CHLORIDE) WITH POLY(METHYL METHACRYLATE)

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; CHENG Rongshi

    1988-01-01

    IR spectral shifts of carbonyl vibrational absorption for ethyl acetate, which acts analogically as the structural unit of poly(methyl methacrylate), in cyclohexane, chloroform, chlorinated paraffins, poly(vinyl chloride) and chlorinated poly(vinyl chloride) were measured. The results suggest that there are specific interactions between the carbonyl groups and the chlorinated hydrocarbons which could be responsible for the apparent compatibility of poly(vinyl chloride) -poly(methyl methacrylate) and chlorinated poly(vinyl chloride) -poly(methyl methacrylate) blends. Additionally, the effects of the preparation mode of blend films on phase separation and observed compatibility are discussed.

  8. A High Power Density, High Efficiency Hydrogen-Chlorine Regenerative Fuel Cell with a Low Precious Metal Content Catalyst

    OpenAIRE

    Huskinson, Brian; Rugolo, Jason; Mondal, Sujit K.; Aziz, Michael J.

    2012-01-01

    We report the performance of a hydrogen-chlorine electrochemical cell with a chlorine electrode employing a low precious metal content alloy oxide electrocatalyst for the chlorine electrode: (Ru_0.09Co_0.91)_3O_4. The cell employs a commercial hydrogen fuel cell electrode and transports protons through a Nafion membrane in both galvanic and electrolytic mode. The peak galvanic power density exceeds 1 W cm^-2, which is twice previous literature values. The precious metal loading of the chlorin...

  9. The chlorine isotopic composition of Martian meteorites 1: Chlorine isotope composition of Martian mantle and crustal reservoirs and their interactions

    Science.gov (United States)

    Williams, J. T.; Shearer, C. K.; Sharp, Z. D.; Burger, P. V.; McCubbin, F. M.; Santos, A. R.; Agee, C. B.; McKeegan, K. D.

    2016-11-01

    The Martian meteorites record a wide diversity of environments, processes, and ages. Much work has been done to decipher potential mantle sources for Martian magmas and their interactions with crustal and surface environments. Chlorine isotopes provide a unique opportunity to assess interactions between Martian mantle-derived magmas and the crust. We have measured the Cl-isotopic composition of 17 samples that span the range of known ages, Martian environments, and mantle reservoirs. The 37Cl of the Martian mantle, as represented by the olivine-phyric shergottites, NWA 2737 (chassignite), and Shergotty (basaltic shergottite), has a low value of approximately -3.8‰. This value is lower than that of all other planetary bodies measured thus far. The Martian crust, as represented by regolith breccia NWA 7034, is variably enriched in the heavy isotope of Cl. This enrichment is reflective of preferential loss of 35Cl to space. Most basaltic shergottites (less Shergotty), nakhlites, Chassigny, and Allan Hills 84001 lie on a continuum between the Martian mantle and crust. This intermediate range is explained by mechanical mixing through impact, fluid interaction, and assimilation-fractional crystallization.

  10. Aquifer Storage Recovery (ASR) of chlorinated municipal drinking water in a confined aquifer

    Science.gov (United States)

    Izbicki, John A.; Petersen, Christen E.; Glotzbach, Kenneth J.; Metzger, Loren F.; Christensen, Allen H.; Smith, Gregory A.; O'Leary, David R.; Fram, Miranda S.; Joseph, Trevor; Shannon, Heather

    2010-01-01

    About 1.02 x 106 m3 of chlorinated municipal drinking water was injected into a confined aquifer, 94-137 m below Roseville, California, between December 2005 and April 2006. The water was stored in the aquifer for 438 days, and 2.64 x 106 m3 of water were extracted between July 2007 and February 2008. On the basis of Cl data, 35% of the injected water was recovered and 65% of the injected water and associated disinfection by-products (DBPs) remained in the aquifer at the end of extraction. About 46.3 kg of total trihalomethanes (TTHM) entered the aquifer with the injected water and 37.6 kg of TTHM were extracted. As much as 44 kg of TTHMs remained in the aquifer at the end of extraction because of incomplete recovery of injected water and formation of THMs within the aquifer by reactions with freechlorine in the injected water. Well-bore velocity log data collected from the Aquifer Storage Recovery (ASR) well show as much as 60% of the injected water entered the aquifer through a 9 m thick, high-permeability layer within the confined aquifer near the top of the screened interval. Model simulations of ground-water flow near the ASR well indicate that (1) aquifer heterogeneity allowed injected water to move rapidly through the aquifer to nearby monitoring wells, (2) aquifer heterogeneity caused injected water to move further than expected assuming uniform aquifer properties, and (3) physical clogging of high-permeability layers is the probable cause for the observed change in the distribution of borehole flow. Aquifer heterogeneity also enhanced mixing of native anoxic ground water with oxic injected water, promoting removal of THMs primarily through sorption. A 3 to 4-fold reduction in TTHM concentrations was observed in the furthest monitoring well 427 m downgradient from the ASR well, and similar magnitude reductions were observed in depth-dependent water samples collected from the upper part of the screened interval in the ASR well near the end of the extraction

  11. Prompt gamma ray evaluation for chlorine analysis in blended cement concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; Kalakada, Zameer; Al-Amoudi, O S B

    2014-12-01

    Single prompt gamma ray energy has been evaluated to measure chlorine concentration in fly ash (FA), Super-Pozz (SPZ) and blast furnace slag (BFS) cement concrete specimens using a portable neutron generator-based Prompt Gamma Neutron Activation (PGNAA) setup. The gamma ray yield data from chloride concentration measurement in FA, SPZ and BFS cement concretes for 2.86-3.10, 5.72 and 6.11MeV chlorine gamma rays were analyzed to identify a gamma ray with common slope (gamma ray yield/Cl conc. wt%) for the FA, BFS and SPZ cement concretes. The gamma ray yield data for FA and SPZ cement concretes with varying chloride concentration were measured previously using a portable neutron generator-based PGNAA setup. In the current study, new data have been measured for chlorine detection in the BFS cement concrete using a portable neutron generator-based PGNAA setup for 2.86-3.10, 5.72, and 6.11MeV chlorine gamma rays. The minimum detection limit of chlorine in BFS cement concrete (MDC) was found to be 0.034±0.010, 0.032±0.010, 0.033±0.010 for 2.86-3.10, 5.72 and 6.11MeV gamma ray, respectively. The new BFS cement concrete data, along with the previous measurements for FA and SPZ cement concretes, have been utilized to identify a gamma ray with a common slope to analyze the Cl concentration in all of these blended cement concretes. It has been observed that the 6.11MeV chlorine gamma ray has a common slope of 5295±265 gamma rays/wt % Cl concentration for the portable neutron generator-based PGNAA setup. The minimum detectable concentration (MDC) of chlorine in blended cement concrete was measured to be 0.033±0.010wt % for the portable neutron generator-based PGNAA. Thus, the 6.11MeV chlorine gamma ray can be used for chlorine analysis of blended cement concretes.

  12. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Chusaksri, Sarinma [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand); Sutthivaiyakit, Somyote [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Sedlak, David L., E-mail: sedlak@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Sutthivaiyakit, Pakawadee, E-mail: fscipws@ku.ac.th [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Mechanism of chlorine reaction with phenylurea compounds has been studied. Black-Right-Pointing-Pointer It depends on both chlorinating species and substitutents on the compounds. Black-Right-Pointing-Pointer Main products were identified using LC-MS/MS and authentic standards. Black-Right-Pointing-Pointer Their transformation under normal drinking water disinfection was predicted. - Abstract: Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3 Prime -N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25 Degree-Sign C and pH 7 were 0.76 {+-} 0.16, 0.52 {+-} 0.11, 0.39 {+-} 0.02, 0.27 {+-} 0.04 and 0.23 {+-} 0.05 M{sup -1} s{sup -1} for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be

  13. A solar-driven UV/Chlorine advanced oxidation process.

    Science.gov (United States)

    Chan, Po Yee; Gamal El-Din, Mohamed; Bolton, James R

    2012-11-01

    An overlap of the absorption spectrum of the hypochlorite ion (OCl(-)) and the ultraviolet (UV) end of the solar emission spectrum implies that solar photons can probably initiate the UV/chlorine advanced oxidation process (AOP). The application of this solar process to water and wastewater treatment has been investigated in this study. At the bench-scale, the OCl(-) photolysis quantum yield at 303 nm (representative of the lower end of the solar UV region) and at concentrations from 0 to 4.23 mM was 0.87 ± 0.01. Also the hydroxyl radical yield factor (for an OCl(-) concentration of 1.13 mM) was 0.70 ± 0.02. Application of this process, at the bench-scale and under actual sunlight, led to methylene blue (MB) photobleaching and cyclohexanoic acid (CHA) photodegradation. For MB photobleaching, the OCl(-) concentration was the key factor causing an increase in the pseudo first-order rate constants. The MB photobleaching quantum yield was affected by the MB concentration, but not much by the OCl(-) concentration. For CHA photodegradation, an optimal OCl(-) concentration of 1.55 mM was obtained for a 0.23 mM CHA concentration, and a scavenger effect was observed when higher OCl(-) concentrations were applied. Quantum yields of 0.09 ± 0.01 and 0.89 ± 0.06 were found for CHA photodegradation and OCl(-) photolysis, respectively. In addition, based on the Air Mass 1.5 reference solar spectrum and experimental quantum yields, a theoretical calculation method was developed to estimate the initial rate for photoreactions under sunlight. The theoretical initial rates agreed well with the experimental rates for both MB photobleaching and CHA photodegradation.

  14. The Potential Feasibility of Chlorinic Photosynthesis on Extrasolar Planets

    Science.gov (United States)

    Haas, Johnson

    2009-09-01

    It is highly likely that the first convincing evidence of extrasolar life will arrive in the form of atmospheric absorption spectra. The modern search for life-bearing extrasolar planets emphasizes the potential detection of O2 and O3 absorption spectra in exoplanetary atmospheres as archetypal signatures of biology. However, oxygenic photosynthesis apparently failed to evolve independently more than once on Earth, and is thus unlikely to be reliably ubiquitous throughout the universe. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This study examines the potential feasibility of one such exotic metabolism: chlorinic photosynthesis (CPS), defined as biologically-mediated halogenation of aqueous chloride to HClO, Cl2 or partially-oxidized intermediates (e.g. haloalkanes, haloacids, haloaromatics), coupled with photosynthetic CO2 fixation. This metabolic couple is feasible thermodynamically and appears to be geochemically plausible under approximately terrestrial conditions. This study hypothesizes that planetary biospheres dominated by CPS would develop atmospheres enriched with dihalogens and other halogenated compounds, evolve a highly oxidizing surface geochemical environment, and foster biological selection pressures favoring halogen resistance and eventual metazoan heterotrophy based on dihalogen and halocarbon respiration. Planets favoring the evolution of CPS would probably receive equivalent or greater surface UV flux than Earth did in the Paleoarchean (promoting abiotic photo-oxidation of aqueous halides, and establishing a strong biological selective pressure toward their accommodation), and would orbit stars having equivalent or greater bulk metallicities (promoting greater planetary halide abundances) relative to the Sun. Directed searches for such worlds should probably focus on A, F and G0 spectral class stars having bulk

  15. Transcriptional and phenotypic responses of Listeria monocytogenes to chlorine dioxide.

    Science.gov (United States)

    Pleitner, Aaron M; Trinetta, Valentina; Morgan, Mark T; Linton, Richard L; Oliver, Haley F

    2014-05-01

    Significant food-borne disease outbreaks have occurred from consumption of ready-to-eat foods, including produce, contaminated with Listeria monocytogenes. Challenging food matrices (e.g., cantaloupe, sprouts) with limited processing steps postharvest to reduce pathogen loads have underscored a need for new mitigation strategies. Chlorine dioxide (ClO2) is increasingly being used in produce and other food systems to reduce food-borne pathogen levels. The goal of this study was to characterize the transcriptional response and survival of L. monocytogenes 10403S exposed to ClO2. The transcriptional profile of log-phase cells exposed to 300 mg/liter ClO2 for 15 min was defined by whole-genome microarray. A total of 340 genes were significantly differentially expressed. Among the differentially expressed genes, 223 were upregulated (fold change ≥ 1.5; adjusted P value < 0.05) in role categories responsible for protein fate, cellular processes, and energy metabolism. There were 113 and 16 genes differentially expressed belonging to regulatory networks of σ(B) and CtsR, respectively. We assessed L. monocytogenes 10403S survival after exposure to 100, 300, and 500 mg/liter aqueous ClO2 in brain heart infusion (BHI) broth; there was a significant difference between cells exposed to 500 mg/liter ClO2 and those exposed to all other conditions over time (P value < 0.05). Isogenic ΔsigB and ΔctsR mutants exposed to 300 mg/liter ClO2 were more sensitive to ClO2 than the wild type under the same conditions. These results provide an initial insight into the mechanisms that L. monocytogenes employs to survive sublethal ClO2 and further our understanding of the inactivation mechanisms of this increasingly used sanitizer.

  16. Chlorine Dioxide Gas Sterilization under Square-Wave Conditions

    Science.gov (United States)

    Jeng, David K.; Woodworth, Archie G.

    1990-01-01

    Experiments were designed to study chlorine dioxide (CD) gas sterilization under square-wave conditions. By using controlled humidity, gas concentration, and temperature at atmospheric pressure, standard biological indicators (BIs) and spore disks of environmental isolates were exposed to CD gas. The sporicidal activity of CD gas was found to be concentration dependent. Prehumidification enhanced the CD activity. The D values (time required for 90% inactivation) of Bacillus subtilis subsp. niger ATCC 9372 BIs were estimated to be 1.5, 2.5, and 4.2 min when exposed to CD concentrations of 30, 15, and 7 mg/liter, respectively, at 23°C and ambient (20 to 40%) relative humidity (RH). Survivor tailings were observed. Prehumidification of BIs to 70 to 75% RH in an environmental chamber for 30 min resulted in a D value of 1.6 min after exposure to a concentration of 6 to 7 mg of CD per liter at 23°C and eliminated survivor tailing. Prolonging prehumidification at 70 to 75% RH for up to 16 h did not further improve the inactivation rate. Prehumidification by ultrasonic nebulization was found to be more effective than prehumidification in the environmental chamber, improving the D value to 0.55 min at a CD concentration of 6 to 7 mg/liter. Based on the current observations, CD gas is estimated, on a molar concentration basis, to be 1,075 times more potent than ethylene oxide as a sterilant at 30°C. A comparative study showed B. subtilis var. niger BIs were more resistant than other types of BIs and most of the tested bacterial spores of environmental isolates. PMID:16348127

  17. Evaluation of chlorine dioxide based product as a hatchery sanitizer.

    Science.gov (United States)

    Maharjan, P; Cox, S; Gadde, U; Clark, F D; Bramwell, K; Watkins, S E

    2016-12-05

    Formaldehyde is commonly used to overcome contaminants introduced by hatching eggs or water supply in the hatcher cabinets. However, health risks associated with its use make economical alternatives important. This project evaluated a chlorine dioxide based product (CDBP) (0.3% concentrate) as a hatchery sanitizer in decontaminating microbial populations on the shell surface of hatching eggs (>18 d old), as well as its impact on hatchability and chick performance. Hatchers (0.20 m(2)) designed to hold approximately 50 eggs and equipped with circulation fans, heaters, and thermostats were used for the evaluation. For each of the 2 trials conducted, 450 hatching eggs were obtained and incubated in a common setter. Eggs used in trial 1 were floor eggs whereas in trial 2 nest eggs were used. On d 18 of incubation, eggs were removed from the setter, and viable eggs were randomly allocated to 9 hatchers. Pre-treatment egg rinse samples (10 eggs per hatcher) were collected for initial microbial analysis. Three hatchers were treated with CDBP and 3 hatchers with a formaldehyde based product (FBP). Three untreated hatchers served as control (C). Prior to hatch, 10 eggs/incubator, not previously rinsed, were used for post treatment microbial counts. The hatched chicks were reared until d 21 in floor pens with a common starter diet. For the CDBP treated eggs, hatchability and chick performance (weight gains, mortality, and FCR on d 7 and d 21) were similar to the other treatments. The application rate of CDBP evaluated in this study was not an effective antimicrobial alternative to formaldehyde for sanitizing hatching eggs in hatcher cabinets prior to hatch.

  18. Inhalation a significant exposure route for chlorinated organophosphate flame retardants.

    Science.gov (United States)

    Schreder, Erika D; Uding, Nancy; La Guardia, Mark J

    2016-05-01

    Chlorinated organophosphate flame retardants (ClOPFRs) are widely used as additive flame retardants in consumer products including furniture, children's products, building materials, and textiles. Tests of indoor media in homes, offices, and other environments have shown these compounds are released from products and have become ubiquitous indoor pollutants. In house dust samples from Washington State, U.S.A., ClOPFRs were the flame retardants detected in the highest concentrations. Two ClOPFRs, tris(1,3-dichloro-2-propyl)phosphate (TDCPP or TDCIPP) and tris(2-chloroethyl)phosphate (TCEP), have been designated as carcinogens, and there is growing concern about the toxicity of the homologue tris(1-chloro-2-propyl)phosphate (TCPP or TCIPP). In response to concerns about exposure to these compounds, the European Union and a number of U.S. states have taken regulatory action to restrict their use in certain product categories. To better characterize exposure to ClOPFRs, inhalation exposure was assessed using active personal air samplers in Washington State with both respirable and inhalable particulate fractions collected to assess the likelihood particles penetrate deep into the lungs. Concentrations of ∑ClOPFRs (respirable and inhalable) ranged from 97.1 to 1190 ng m(-3) (mean 426 ng m(-3)), with TCPP detected at the highest concentrations. In general, higher levels were detected in the inhalable particulate fraction. Total intake of ClOPFRs via the inhalation exposure route was estimated to exceed intake via dust ingestion, indicating that inhalation is an important route that should be taken into consideration in assessments of these compounds.

  19. Science and policy in risk assessments of chlorinated ethenes.

    Science.gov (United States)

    Rudén, Christina

    2006-09-01

    In this article the use of data obtained from standardized experimental methods, for example, as specified in OECD guidelines for the testing of chemicals, epidemiology data, and mechanism data obtained from nonstandardized experimental methods in carcinogen risk assessment is scrutinized using the most recent risk assessments made by International Agency for Research on Cancer (IARC), the MAK(MAK)-Kommission, World Health Organization (WHO), European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC), and American Conference of Governmental Industrial Hygienists (ACGIH) for the four chlorinated ethenes as examples. The analysis shows that there was little controversy among these risk assessors about the interpretation of standardized animal data. On the other hand, they differ in their interpretation of epidemiology data, in particular in their assessment of statistical significance including the use of meta-analyses, and in quality evaluation of studies initiated on the basis of a priori concerns for carcinogenicity. The selection of mechanism data for species extrapolation is diverse among these risk assessors. Furthermore, in some cases they refrain from transparently motivating significant claims about mechanisms of toxicity by avoiding to give (explicit) references to the sources of information forming the basis of these claims or conclusions. This practice is not according to the scientific standards that should be required of a risk assessment document, and it makes it difficult to follow the argumentation and consequently to scrutinize the scientific accuracy of the conclusions drawn. In this article it is concluded that in some of these risk assessment documents, the use of mechanism data is not according to the scientific standards that should be required. It is furthermore concluded that if the use of mechanism data in these documents are representative of risk assessments in general, then there is an urgent need for further development and

  20. Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Aleisa C [ORNL

    2015-01-01

    Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE Aleisa Bloom, (Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA) Robert Lyon (bob.lyon@aecom.com), Laurie Stenberg, and Holly Brown (AECOM, Germantown, Maryland, USA) ABSTRACT: Past disposal practices at Dover Air Force Base (AFB), Delaware, created a large solvent plume called Area 6 (about 1 mile long, 2,000 feet wide, and 345 acres). The main contaminants are PCE, TCE, and their degradation products. The remedy is in-situ accelerated anaerobic bioremediation (AAB). AAB started in 2006 and is focusing on source areas and downgradient plume cores. Direct-push injections occurred in source areas where contamination is typically between 5 and 20 feet below ground surface. Lower concentration dissolved-phased contamination is present downgradient at 35 and 50 feet below ground surface. Here, permanent injection/extraction wells installed in transects perpendicular to the flow of groundwater are used to apply AAB. The AAB substrate is a mix of sodium lactate, emulsified vegetable oil, and nutrients. After eight years, dissolved contaminant mass within the main 80-acre treatment area has been reduced by over 98 percent. This successful application of AAB has stopped the flux of contaminants to the more distal portions of the plume. While more time is needed for effects to be seen in the distal plume, AAB injections will soon cease, and the remedy will transition to natural attenuation. INTRODUCTION Oak Ridge National Laboratory Environmental Science Division (ORNL) and AECOM (formerly URS Corporation) have successfully implemented in situ accelerated anaerobic bioremediation (AAB) to remediate chlorinated solvent contamination in a large, multi-sourced groundwater plume at Dover Air Force Base (AFB). AAB has resulted in significant reductions of dissolved phase chlorinated solvent concentrations. This plume, called Area 6, was originally over 1 mile in length and over 2,000 feet wide (Figure 1