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Sample records for chlorine isotopes

  1. Chlorine isotopes potential as geo-chemical tracers

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Pradhan, U.K.; Banerjee, R.

    The potential of chlorine isotopes as tracers of geo-chemical processes of earth and the oceans is highlighted based on systematic studies carried out in understanding the chlorine isotope fractionation mechanism, its constancy in seawater and its...

  2. 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.

  3. 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.

  4. 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.

  5. Application of compound specific 13C isotope investigations of chlorinated hydrocarbons in contaminated groundwaters

    International Nuclear Information System (INIS)

    Osenbrueck, K.; Heidinger, M.; Voropaev, A.; Ertl, S.; Eichinger, L.

    2002-01-01

    Full text: Chlorinated hydrocarbons are one of the most common pollutants found in groundwater. Due to complex contamination situations with overlapping contamination plumes the assessment of the organic contaminants requires the installation of expensive observation wells and high analytical effort. Here the determination of the stable isotope ratio 13 C/ 12 C of the organic compounds offers a promising and efficient tool to investigate the origin and the biodegradation characteristics of the chlorinated hydrocarbons in groundwater. The application of the method is based on characteristic isotope fingerprints, differing in chlorinated solvents. This isotope fingerprint is derived from different production pathways and is not influenced by transport or by retardation processes in the underground. Due to the fact, that two different contaminations can easily be distinguished by isotope ratios, an improved distinction of spatially and temporally different contamination plumes might be possible. In course of biologically mediated degradation processes a shift of the isotope ratios between the precursor and the product can frequently be observed, such as with denitrification or sulfate reduction processes. The isotope fractionation is due to a preferential reaction of the bonds formed by the lighter isotopes and leads to a progressive enrichment of the heavy isotopes in the precursor while the product becomes depleted in the heavy isotopes. Biological degradation of the highly chlorinated hydrocarbons is due to a co-metabolic dechlorinisation. Tetrachloroethene (PCE) for example degrades under anoxic conditions via trichloroethene (TCE) to cis-1,2-dichloroethene (cDCE). Subsequent degradation to vinyl chloride (VC) and ethene may appear under aerobic as well as reducing environments depending on the site specific conditions. In several laboratory studies it has been shown, that biodegradation of the chlorinated hydrocarbons is accompanied by an isotope fractionation of

  6. Chlorine isotope effects from isotope ratio mass spectrometry suggest intramolecular C-Cl bond competition in trichloroethene (TCE) reductive dehalogenation.

    Science.gov (United States)

    Cretnik, Stefan; Bernstein, Anat; Shouakar-Stash, Orfan; Löffler, Frank; Elsner, Martin

    2014-05-20

    Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (bio)chemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE) dehalogenation was investigated. Selective biotransformation reactions (i) of tetrachloroethene (PCE) to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii) of TCE to cis-1,2-dichloroethene (cis-DCE) in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were -19.0‰ ± 0.9‰ (PCE) and -12.2‰ ± 1.0‰ (TCE) (95% confidence intervals). Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (-5.0‰ ± 0.1‰) and TCE (-3.6‰ ± 0.2‰). In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by -16.3‰ ± 1.4‰ (standard error)) than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of -2.4‰ ± 0.3‰ and the product chloride an isotope effect of -6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals). A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect). These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition). This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I) or single electron transfer as reductive dehalogenation mechanisms.

  7. Chlorine isotope investigation of natural attenuation of trichloroethene in an aerobic aquifer

    International Nuclear Information System (INIS)

    Sturchio, N.C.; Heraty, L.J.; Huang, L.; Holt, B.D.; Abrajano, T.A. Jr.; Clausen, J.L.

    1998-01-01

    Natural attenuation of chlorinated aliphatic hydrocarbons (CAHs) can be an important mechanism for groundwater remediation. It is difficult to determine the effectiveness of natural CAH attenuation from chemical analyses of groundwater samples because mixing, dispersion, and secondary reactions can mask the chemical evidence of attenuation. In this paper, the authors explore the application of stable chlorine isotope ratio measurements as a new tool for evaluating natural attenuation of CAHs. They report stable isotope ratios of chlorine in both trichloroethene (TCE) and inorganic chloride in groundwater from an aerobic aquifer beneath an extensively contaminated industrial site, the Paducah Gaseous Diffusion Plant in western Kentucky. Variations in the concentrations and chlorine isotope ratios of TCE and chloride in the groundwater are consistent with those expected from natural attenuation. These data support a model in which partial TCE degradation occurred in relatively impermeable, clay-rich sediments above the aquifer, and little or no further degradation of TCE occurred within the aquifer. A record of changing conditions within the TCE source area can be inferred from the spatial variation of chlorine isotope ratios for TCE and chloride within the plume

  8. 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

    The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (q...... 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......DCE. The significant enrichment of 13C in VC indicates that VC was transformed further, although the mechanismcould not be determined. The transformation of cDCEwas the rate limiting step as no accumulation of VC occurred. In summary, the study demonstrates that carbon–chlorine isotope analysis and qPCR combinedwith...

  9. Chlorine Isotope Effects from Isotope Ratio Mass Spectrometry Suggest Intramolecular C-Cl Bond Competition in Trichloroethene (TCE Reductive Dehalogenation

    Directory of Open Access Journals (Sweden)

    Stefan Cretnik

    2014-05-01

    Full Text Available Chlorinated ethenes are prevalent groundwater contaminants. To better constrain (biochemical reaction mechanisms of reductive dechlorination, the position-specificity of reductive trichloroethene (TCE dehalogenation was investigated. Selective biotransformation reactions (i of tetrachloroethene (PCE to TCE in cultures of Desulfitobacterium sp. strain Viet1; and (ii of TCE to cis-1,2-dichloroethene (cis-DCE in cultures of Geobacter lovleyi strain SZ were investigated. Compound-average carbon isotope effects were −19.0‰ ± 0.9‰ (PCE and −12.2‰ ± 1.0‰ (TCE (95% confidence intervals. Using instrumental advances in chlorine isotope analysis by continuous flow isotope ratio mass spectrometry, compound-average chorine isotope effects were measured for PCE (−5.0‰ ± 0.1‰ and TCE (−3.6‰ ± 0.2‰. In addition, position-specific kinetic chlorine isotope effects were determined from fits of reactant and product isotope ratios. In PCE biodegradation, primary chlorine isotope effects were substantially larger (by −16.3‰ ± 1.4‰ (standard error than secondary. In TCE biodegradation, in contrast, the product cis-DCE reflected an average isotope effect of −2.4‰ ± 0.3‰ and the product chloride an isotope effect of −6.5‰ ± 2.5‰, in the original positions of TCE from which the products were formed (95% confidence intervals. A greater difference would be expected for a position-specific reaction (chloride would exclusively reflect a primary isotope effect. These results therefore suggest that both vicinal chlorine substituents of TCE were reactive (intramolecular competition. This finding puts new constraints on mechanistic scenarios and favours either nucleophilic addition by Co(I or single electron transfer as reductive dehalogenation mechanisms.

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

    International Nuclear Information System (INIS)

    Kushita, Kouhei

    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, 35 Cl and 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, 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)

  11. 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)

  12. 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...

  13. Chlorine isotope fractionation during supergene enrichment of copper

    Science.gov (United States)

    Reich, M.; Barnes, J.; Barra, F.; Milojevic, C.; Drew, D.

    2017-12-01

    Supergene enrichment of Cu deposits in the Atacama Desert has played a critical role in making this the prime Cu-producing province of the world. The Cu-hydroxychloride atacamite is a major component of supergene zones in this region whereas in similar deposits elsewhere it is rare. Atacamite requires saline water to form and dissolves rapidly when exposed to fresh, meteoric water. Previous chlorine stable isotope data [1] for atacamite mineralization at the Radomiro Tomic, Chuquicamata and Mina Sur Cu deposits show δ37Cl values that range from -0.1 to +0.2‰, indicating a similar nonmagmatic source for the introduction of chloride. However, distal atacamite mineralization on the periphery of these orebodies show more fractionated and lighter δ37Cl values (-3.2 to -0.1‰). Although little disagreement currently exists about the involvement of saline groundwater during the formation of atacamite [2], no δ37Cl data are currently available for atacamite within a single deposit and/or supergene enrichment profile that allow explaining the aforementioned differences in the observed δ37Cl values. Furthermore, no experimental data for chlorine isotope fractionation between Cu-hydroxychloride minerals and water exist that help evaluate possible mechanisms of fractionation along the groundwater flow path. Here we present a new database that combines detailed mineralogical observations with δ37Cl data of atacamite along a thick ( 100 m) supergene enrichment profile at the Barreal Seco IOCG deposit in the Atacama Desert of northern Chile. Chlorine stable isotope data of atacamite vary between -0.62 and +2.1 ‰ and show a well-defined trend where δ37Cl values progressively decrease (become lighter) with depth. These data, when combined with new experimental determinations of chlorine isotope fractionation between atacamite and water, point to changes triggered by the progressive deepening of groundwater tables during Andean uplift and the extreme desiccation of

  14. 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...

  15. Boron and chlorine isotopic signatures of seawater in the Central Indian Ridge

    Digital Repository Service at National Institute of Oceanography (India)

    Shirodkar, P.V.; Xiao, Y.K.; Hai, L.

    (CIR). Boron and chlorine isotopic measurements were made using positive thermal ionization mass spectrometry (TIMS) of Cs2BO4 + and Cs2Cl+ ions respectively, mainly to understand their isotopic behaviours to elucidate the consistency of boron...

  16. [Changes of chlorine isotope composition characterize bacterial dehalogenation of dichloromethane].

    Science.gov (United States)

    Ziakun, A M; Firsova, Iu E; Torgonskaia, M L; Doronina, N V; Trotsenko, Iu A

    2007-01-01

    Fractionation of dichloromethane (DCM) molecules with different chlorine isotopes by aerobic methylobacteria Methylobacterium dichloromethanicum DM4 and Albibacter nethylovorans DM10; cell-free extract of strain DM4; and transconjugant Methylobacterium evtorquens Al1/pME 8220, expressing the dcmA gene for DCM dehalogenase but unable to grow on DCM, was studied. Kinetic indices of DCM isotopomers for chlorine during bacterial dehalogenation and diffusion were compared. A two-step model is proposed, which suggests diffusional DCM transport to bacterial cells.

  17. Validation of chlorine and oxygen isotope ratio analysis to differentiate perchlorate sources and to document perchlorate biodegradation

    Science.gov (United States)

    Paul B. Hatzinger,; Böhlke, John Karl; Sturchio, Neil C.; Gu, Baohua

    2013-01-01

    Increased health concerns about perchlorate (ClO4-) during the past decade and subsequent regulatory considerations have generated appreciable interest in source identification. The key objective of the isotopic techniques described in this guidance manual is to provide evidence concerning the origin of ClO4- in soils and groundwater and, more specifically, whether that ClO4- is synthetic or natural. Chlorine and oxygen isotopic analyses of ClO4- provide the primary direct approach whereby different sources of ClO4- can be distinguished from each other. These techniques measure the relative abundances of the stable isotopes of chlorine (37Cl and 35Cl) and oxygen (18O, 17O, and 16O) in ClO4- using isotope-ratio mass spectrometry (IRMS). In addition, the relative abundance of the radioactive chlorine isotope 36Cl is measured using accelerator mass spectrometry (AMS). Taken together, these measurements provide four independent quantities that can be used to distinguish natural and synthetic ClO4- sources, to discriminate different types of natural ClO4-, and to detect ClO4- biodegradation in the environment. Other isotopic, chemical, and geochemical techniques that can be applied in conjunction with isotopic analyses of ClO4- to provide supporting data in forensic studies are also described.

  18. A stable isotope approach for source apportionment of chlorinated ethene plumes at a complex multi-contamination events urban site

    Science.gov (United States)

    Nijenhuis, Ivonne; Schmidt, Marie; Pellegatti, Eleonora; Paramatti, Enrico; Richnow, Hans Hermann; Gargini, Alessandro

    2013-10-01

    The stable carbon isotope composition of chlorinated aliphatic compounds such as chlorinated methanes, ethanes and ethenes was examined as an intrinsic fingerprint for apportionment of sources. A complex field site located in Ferrara (Italy), with more than 50 years history of use of chlorinated aliphatic compounds, was investigated in order to assess contamination sources. Several contamination plumes were found in a complex alluvial sandy multi-aquifer system close to the river Po; sources are represented by uncontained former industrial and municipal dump sites as well as by spills at industrial areas. The carbon stable isotope signature allowed distinguishing 2 major sources of contaminants. One source of chlorinated aliphatic contaminants was strongly depleted in 13C (-40‰ which is commonly observed in recent production of chlorinated solvents. The degradation processes in the plumes could be traced interpreting the isotope enrichment and depletion of parent and daughter compounds, respectively. We demonstrate that, under specific production conditions, namely when highly chlorinated ethenes are produced as by-product during chloromethanes production, 13C depleted fingerprinting of contaminants can be obtained and this can be used to track sources and address the responsible party of the pollution in urban areas.

  19. Dependence of chlorine isotope separation in ion exchange chromatography on the nature and concentration of the eluent

    International Nuclear Information System (INIS)

    Heumann, K.G.; Baier, K.

    1980-01-01

    In a heterogeneous electrolyte system of a strongly basic anion exchanger and solutions of NaBF 4 or NaClO 4 we established the influence of the nature and concentration of the eluent in chromatographic experiments on chlorine isotope separation. Results show that when the elctrolyte concentration is increased the degree of isotope separation decreases. With NaBF 4 the separation factor is greater than with NaClO 4 under conditions which are otherwise the same. For electrolyte solutions containing ClO 4 -, NO 3 - and BF 4 - there is a linear relation between the separation factor of the chlorine isotopes and the logarithm of the heat of anion hydration of the elution electrolyte. (orig.)

  20. Carbon, Chlorine, and Hydrogen Isotope Fractionation in Transformation of TCE to Ethene by a Dehalococcoides Culture

    NARCIS (Netherlands)

    Kuder, T.; van Breukelen, B.M.; Vanderford, M.; Philip, P.

    2013-01-01

    Carbon (C), chlorine (Cl), and hydrogen (H) isotope effects were determined during dechlorination of TCE to ethene by a mixed Dehalococcoides (Dhc) culture. The C isotope effects for the dechlorination steps were consistent with data published in the past for reductive dechlorination (RD) by Dhc.

  1. Development and validation of an universal interface for compound-specific stable isotope analysis of chlorine (37Cl/35Cl) by GC-high-temperature conversion (HTC)-MS/IRMS.

    Science.gov (United States)

    Renpenning, Julian; Hitzfeld, Kristina L; Gilevska, Tetyana; Nijenhuis, Ivonne; Gehre, Matthias; Richnow, Hans-Hermann

    2015-03-03

    A universal application of compound-specific isotope analysis of chlorine was thus far limited by the availability of suitable analysis techniques. In this study, gas chromatography in combination with a high-temperature conversion interface (GC-HTC), converting organic chlorine in the presence of H2 to gaseous HCl, was coupled to a dual-detection system, combining an ion trap mass spectrometer (MS) and isotope-ratio mass spectrometer (IRMS). The combination of the MS/IRMS detection enabled a detailed characterization, optimization, and online monitoring of the high-temperature conversion process via ion trap MS as well as a simultaneous chlorine isotope analysis by the IRMS. Using GC-HTC-MS/IRMS, chlorine isotope analysis at optimized conversion conditions resulted in very accurate isotope values (δ(37)Cl(SMOC)) for measured reference material with known isotope composition, including chlorinated ethylene, chloromethane, hexachlorocyclohexane, and trichloroacetic acids methyl ester. Respective detection limits were determined to be <15 nmol Cl on column with achieved precision of <0.3‰.

  2. 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.

    *Cl+ ion. Int. J. Mass Spectrom. Ion Process., 116: crysatallization of saline minerals in salt lake. J. Salt Lake 183-192. Sci., 2: 35-40 (in Chinese). Xiao, Y.K., Sun, D.P., Wang, Y.H., Qi, H.P. and Jin, L., 1992. Boron isotopic compositions of brine..., sediments, and source water in Da Qaidam Lake, Qinghai, China. Geochim. Cos- mochim. Acta, 56: 1.561-1568. Xiao, Y.K., Jin, L., Liu. W.G., Qi, H.P., Wang, W.H. and Sun, D.P., 1994a. The isotopic compositions of chlorine in Da Qaidam Lake. Chin. Sci...

  3. Tracing chlorine sources of thermal and mineral springs along and across the Cascade Range using halogen and chlorine isotope compositions

    Science.gov (United States)

    Cullen, Jeffrey T.; Barnes, Jaime D.; Hurwitz, Shaul; Leeman, William P.

    2015-01-01

    In order to provide constraints on the sources of chlorine in spring waters associated with arc volcanism, the major/minor element concentrations and stable isotope compositions of chlorine, oxygen, and hydrogen were measured in 28 thermal and mineral springs along the Cascade Range in northwestern USA. Chloride concentrations in the springs range from 64 to 19,000 mg/L and View the MathML source values range from +0.2‰ to +1.9‰ (average=+1.0±0.4‰), with no systematic variation along or across the arc, nor correlations with their presumed underlying basement lithologies. Additionally, nine geochemically well-characterized lavas from across the Mt. St. Helens/Mt. Adams region of the Cascade Range (Leeman et al., 2004 and Leeman et al., 2005) were analyzed for their halogen concentrations and Cl isotope compositions. In the arc lavas, Cl and Br concentrations from the volcanic front are higher than in lavas from the forearc and backarc. F and I concentrations progressively decrease from forearc to backarc, similar to the trend documented for B in most arcs. View the MathML source values of the lavas range from −0.1 to +0.8‰ (average = +0.4±0.3‰). Our results suggest that the predominantly positive View the MathML source values observed in the springs are consistent with water interaction with underlying 37Cl-enriched basalt and/or altered oceanic crust, thereby making thermal spring waters a reasonable proxy for the Cl isotope compositions of associated volcanic rocks in the Cascades. However, waters with View the MathML source values >+1.0‰ also suggest additional contributions of chlorine degassed from cooling magmas due to subsurface vapor–liquid HCl fractionation in which Cl is lost to the aqueous fluid phase and 37Cl is concentrated in the ascending magmatic HCl vapor. Future work is necessary to better constrain Cl isotope behavior during volcanic degassing and fluid–rock interaction in order to improve volatile flux estimates through

  4. Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

    NARCIS (Netherlands)

    Allin, S. J.; Laube, J. C.; Witrant, E.; Kaiser, J.; McKenna, E.; Dennis, P.; Mulvaney, R.; Capron, E.; Martinerie, P.; Roeckmann, Thomas; Blunier, T.; Schwander, J.; Fraser, P. J.; Langenfelds, R. L.; Sturges, W. T.

    2015-01-01

    The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O-3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al.,

  5. Degradation of sulfamethoxazole using ozone and chlorine dioxide - Compound-specific stable isotope analysis, transformation product analysis and mechanistic aspects.

    Science.gov (United States)

    Willach, Sarah; Lutze, Holger V; Eckey, Kevin; Löppenberg, Katja; Lüling, Michelle; Terhalle, Jens; Wolbert, Jens-Benjamin; Jochmann, Maik A; Karst, Uwe; Schmidt, Torsten C

    2017-10-01

    The sulfonamide antibiotic sulfamethoxazole (SMX) is a widely detected micropollutant in surface and groundwaters. Oxidative treatment with e.g. ozone or chlorine dioxide is regularly applied for disinfection purposes at the same time exhibiting a high potential for removal of micropollutants. Especially for nitrogen containing compounds such as SMX, the related reaction mechanisms are largely unknown. In this study, we systematically investigated reaction stoichiometry, product formation and reaction mechanisms in reactions of SMX with ozone and chlorine dioxide. To this end, the neutral and anionic SMX species, which may occur at typical pH-values of water treatment were studied. Two moles of chlorine dioxide and approximately three moles of ozone were consumed per mole SMX degraded. Oxidation of SMX with ozone and chlorine dioxide leads in both cases to six major transformation products (TPs) as revealed by high-resolution mass spectrometry (HRMS). Tentatively formulated TP structures from other studies could partly be confirmed by compound-specific stable isotope analysis (CSIA). However, for one TP, a hydroxylated SMX, it was not possible by HRMS alone to identify whether hydroxylation occurred at the aromatic ring, as suggested in literature before, or at the anilinic nitrogen. By means of CSIA and an analytical standard it was possible to identify sulfamethoxazole hydroxylamine unequivocally as one of the TPs of the reaction of SMX with ozone as well as with chlorine dioxide. H-abstraction and electron transfer at the anilinic nitrogen are suggested as likely initial reactions of ozone and chlorine dioxide, respectively, leading to its formation. Oxidation of anionic SMX with ozone did not show any significant isotopic fractionation whereas the other reactions studied resulted in a significant carbon isotope fractionation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Anaerobic reductive dechlorination of tetrachloroethene: how can dual Carbon-Chlorine isotopic measurements help elucidating the underlying reaction mechanism?

    Science.gov (United States)

    Badin, Alice; Buttet, Géraldine; Maillard, Julien; Holliger, Christof; Hunkeler, Daniel

    2014-05-01

    Chlorinated ethenes (CEs) such as tetrachloroethene (PCE) are common persistent groundwater contaminants. Among clean-up strategies applied to sites affected by such pollution, bioremediation has been considered with a growing interest as it represents a cost-effective, environmental friendly approach. This technique however sometimes leads to an incomplete and slow biodegradation of CEs resulting in an accumulation of toxic metabolites. Understanding the reaction mechanisms underlying anaerobic reductive dechlorination would thus help assessing PCE biodegradation in polluted sites. Stable isotope analysis can provide insight into reaction mechanisms. For chlorinated hydrocarbons, carbon (C) and chlorine (Cl) isotope data (δ13C and δ37Cl) tend to show a linear correlation with a slope (m ≡ ɛC/ɛCl) characteristic of the reaction mechanism [1]. This study hence aims at exploring the potential of a dual C-Cl isotope approach in the determination of the reaction mechanisms involved in PCE reductive dechlorination. C and Cl isotope fractionation were investigated during anaerobic PCE dechlorination by two bacterial consortia containing members of the Sulfurospirillum genus. The specificity in these consortia resides in the fact that they each conduct PCE reductive dechlorination catalysed by one different reductive dehalogenase, i.e. PceADCE which yields trichloroethene (TCE) and cis-dichloroethene (cDCE), and PceATCE which yields TCE only. The bulk C isotope enrichment factors were -3.6±0.3 o for PceATCE and -0.7±0.1o for PceADCE. The bulk Cl isotope enrichment factors were -1.3±0.2 o for PceATCE and -0.9±0.1 o for PceADCE. When applying the dual isotope approach, two m values of 2.7±0.1 and 0.7±0.2 were obtained for the reductive dehalogenases PceATCE and PceADCE, respectively. These results suggest that PCE can be degraded according to two different mechanisms. Furthermore, despite their highly similar protein sequences, each reductive dehalogenase seems

  7. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    Energy Technology Data Exchange (ETDEWEB)

    Palau, Jordi, E-mail: jordi.palau@unine.ch [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Marchesi, Massimo [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Chambon, Julie C.C. [Department of Environmental Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Aravena, Ramon [Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Canals, Àngels [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain); Binning, Philip J.; Bjerg, Poul L. [Department of Environmental Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Otero, Neus; Soler, Albert [Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona, Martí i Franquès, s/n 08028 Barcelona (Spain)

    2014-03-01

    The use of compound specific multi-isotope approach (C and Cl) in the characterization of a chlorinated ethenes contaminated fractured aquifer allows the identification of several sources and contaminant plumes, as well as the occurrence of biodegradation and mixing processes. The study site is located in Spain with contamination resulting in groundwater concentrations of up to 50 mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon, showed a wide range in δ{sup 13}C values from − 15.6 to − 40.5‰ for TCE and from − 18.5 to − 32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the δ{sup 37}Cl values for TCE in the contaminant sources, ranging from + 0.53 to + 0.66‰. Variations of δ{sup 37}Cl and δ{sup 13}C in the different contaminant plumes were used to investigate the role of biodegradation in groundwater. Moreover, the isotopic data were incorporated into a reactive transport model for determination of whether the isotope pattern observed downstream from the tank's source could be explained by the simultaneous effect of mixing and biodegradation. The results demonstrate that a multi-isotope approach is a valuable tool for characterization of complex sites such as fractured bedrock aquifer contaminated by multiple sources, providing important information which can be used by consultants and site managers to prioritize and design more successful remediation strategies. - Highlights: • Origin and fate of CAHs in groundwater by means of multi CSIA ({sup 13}C,{sup 35}Cl) survey • Innovative/new approach tested in a fractured bedrock site • Differentiation of distinct CAH sources • Biodegradation and source mixing recognition in the aquifer.

  8. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    International Nuclear Information System (INIS)

    Palau, Jordi; Marchesi, Massimo; Chambon, Julie C.C.; Aravena, Ramon; Canals, Àngels; Binning, Philip J.; Bjerg, Poul L.; Otero, Neus; Soler, Albert

    2014-01-01

    The use of compound specific multi-isotope approach (C and Cl) in the characterization of a chlorinated ethenes contaminated fractured aquifer allows the identification of several sources and contaminant plumes, as well as the occurrence of biodegradation and mixing processes. The study site is located in Spain with contamination resulting in groundwater concentrations of up to 50 mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon, showed a wide range in δ 13 C values from − 15.6 to − 40.5‰ for TCE and from − 18.5 to − 32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the δ 37 Cl values for TCE in the contaminant sources, ranging from + 0.53 to + 0.66‰. Variations of δ 37 Cl and δ 13 C in the different contaminant plumes were used to investigate the role of biodegradation in groundwater. Moreover, the isotopic data were incorporated into a reactive transport model for determination of whether the isotope pattern observed downstream from the tank's source could be explained by the simultaneous effect of mixing and biodegradation. The results demonstrate that a multi-isotope approach is a valuable tool for characterization of complex sites such as fractured bedrock aquifer contaminated by multiple sources, providing important information which can be used by consultants and site managers to prioritize and design more successful remediation strategies. - Highlights: • Origin and fate of CAHs in groundwater by means of multi CSIA ( 13 C, 35 Cl) survey • Innovative/new approach tested in a fractured bedrock site • Differentiation of distinct CAH sources • Biodegradation and source mixing recognition in the aquifer

  9. Chlorine isotope evidence for the anthropogenic origin of tris-(4-chlorophenyl)methane

    International Nuclear Information System (INIS)

    Holmstrand, Henry; Zencak, Zdenek; Mandalakis, Manolis; Andersson, Per; Gustafsson, Orjan

    2010-01-01

    Research highlights: → TCPMe is a bioaccumulating organochlorine found at significant levels in organisms at high trophic levels, e.g. birds and mammals. → Previous investigations have suggested TCPMe being co-released as a trace byproduct in pesticides such as DDT. → The results from compound-specific chlorine isotope analysis of TCPMe supports the hypothesis that the source of TCPMe is indeed the extensive historical use of DDT. - Abstract: Compound-specific Cl-isotope analysis was performed on the persistent and bioaccumulating compound tris-(4-chlorophenyl)methane (4,4',4''-TCPMe, referred to as TCPMe in this study) to elucidate whether its main source is natural or anthropogenic. Blubber from the Baltic grey seal (Halichoerus grypus) was extracted by continuous acetonitrile partitioning, and the TCPMe was isolated from the extract by preparative-capillary gas chromatography. Chlorine isotope analysis was subsequently performed by sealed-tube combustion in conjunction with thermal-ionization mass spectrometry (TIMS). The δ 37 Cl of TCPMe was -3.5 ± 0.5 per mille, similar to the previously reported δ 37 Cl of technical grade p,p'-DDT (referred to as DDT in this study). The data is not consistent with a putative marine natural source of TCPMe, as enzymatic (biotic) production is reported to give values of δ 37 Cl 37 Cl-TCPMe data thus supports the hypothesis that TCPMe is produced as a byproduct during DDT synthesis and is released to the environment through the same pathways as DDT. It is also consistent with tris-(4-chlorophenyl)methanol as the primary biotransformation product of TCPMe.

  10. Modeling 3D-CSIA data: Carbon, chlorine, and hydrogen isotope fractionation during reductive dechlorination of TCE to ethene.

    Science.gov (United States)

    Van Breukelen, Boris M; Thouement, Héloïse A A; Stack, Philip E; Vanderford, Mindy; Philp, Paul; Kuder, Tomasz

    2017-09-01

    Reactive transport modeling of multi-element, compound-specific isotope analysis (CSIA) data has great potential to quantify sequential microbial reductive dechlorination (SRD) and alternative pathways such as oxidation, in support of remediation of chlorinated solvents in groundwater. As a key step towards this goal, a model was developed that simulates simultaneous carbon, chlorine, and hydrogen isotope fractionation during SRD of trichloroethene, via cis-1,2-dichloroethene (and trans-DCE as minor pathway), and vinyl chloride to ethene, following Monod kinetics. A simple correction term for individual isotope/isotopologue rates avoided multi-element isotopologue modeling. The model was successfully validated with data from a mixed culture Dehalococcoides microcosm. Simulation of Cl-CSIA required incorporation of secondary kinetic isotope effects (SKIEs). Assuming a limited degree of intramolecular heterogeneity of δ 37 Cl in TCE decreased the magnitudes of SKIEs required at the non-reacting Cl positions, without compromising the goodness of model fit, whereas a good fit of a model involving intramolecular CCl bond competition required an unlikely degree of intramolecular heterogeneity. Simulation of H-CSIA required SKIEs in H atoms originally present in the reacting compounds, especially for TCE, together with imprints of strongly depleted δ 2 H during protonation in the products. Scenario modeling illustrates the potential of H-CSIA for source apportionment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  11. To what extent can isotopes help substantiate natural attenuation of chlorinated ethenes?

    DEFF Research Database (Denmark)

    Badin, A.; Broholm, Mette Martina; Hunkeler, D.

    to which isotopes could help substantiate natural attenuation of chlorinated ethenes at the field scale. Our work hence aims at exploring the latter based on data acquired in 2006 in a site located in Denmark which is contaminated with PCE and its end-products TCE, cDCE, and VC. Previous work on this site...... has enabled to demonstrate that PCE and TCE were undergoing reductive dechlorination while cDCE would be at least partially degraded through reductive dechlorination1. However, the magnitude of the contaminants attenuation by biodegradation was not evaluated. Based on simple modeling including...

  12. Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: mass balance, PCR and compound-specific stable isotope analysis.

    OpenAIRE

    Courbet Christelle; Rivière Agnès; Jeannottat Simon; Rinaldi Sandro; Hunkeler Daniel; Bendjoudi Hocine; De Marsily Ghislain

    2011-01-01

    This work describes the use of different complementing methods (mass balance polymerase chain reaction assays and compound specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at vario...

  13. Chlorine isotopes and their application to groundwater dating at Olkiluoto

    International Nuclear Information System (INIS)

    Gascoyne, M.

    2014-09-01

    The chlorine isotopes 36 Cl and 37 Cl have been shown to be useful tracers of groundwater, and for investigations of sources of dissolved Cl, mixing of fluids, water-rock interactions in sedimentary environments and in identifying solute sources and transport mechanisms. In addition, the radioactive isotope, 36 Cl, is a useful tracer for determining the residence time of groundwater. This report examines the results of Cl isotopic analysis of groundwaters from as deep as 1000 m at the Olkiluoto site in southwest Finland. Thirty-four samples were analysed for 36 Cl/Cl and 29 were analysed for 37 Cl (expressed as δ 37 Cl). The value δ 37 Cl was found to stabilize at higher salinities and the maximum range of δ 37 Cl was from about - 0.6 to +0.6 per mille. Because of this limited range and the relatively large error margins associated with the δ 37 Cl measurement, the usefulness of this ratio appears to be limited. Therefore, the main part of this report is largely focused on 36 Cl. Estimation of residence time of 36 Cl gives results that support the presence of at least five groundwater types at Olkiluoto. The consistency of 36 Cl/Cl ratios in groundwaters of several widely separated, deep locations and different rock compositions, suggests that these deeper groundwaters are in secular equilibrium and, therefore, likely to be older than 1.5 million years. (orig.)

  14. Monitoring of the aerobe biodegradation of chlorinated organic solvents by stable isotope analysis

    Science.gov (United States)

    Horváth, Anikó; Futó, István; Palcsu, László

    2014-05-01

    Our chemical-biological basic research aims to eliminate chlorinated environmental contaminants from aquifers around industrial areas in the frame of research program supported by the European Social Fund (TÁMOP-4.2.2.A-11/1/KONV-2012-0043). The most careful and simplest way includes the in situ biodegradation with the help of cultured and compound specific strains. Numerous members of Pseudomonas bacteria are famous about function of bioremediation. They can metabolism the environmental hazardous chemicals like gas oils, dyes, and organic solvents. Our research based on the Pseudomonas putida F1 strain, because its ability to degrade halogenated hydrocarbons such as trichloroethylene. Several methods were investigated to estimate the rate of biodegradation, such as the measurement of the concentration of the pollutant along the contamination pathway, the microcosm's studies or the compound specific stable isotope analysis. In this area in the Transcarpathian basin we are pioneers in the stable isotope monitoring of biodegradation. The main goal is to find stable isotope fractionation factors by stable isotope analysis, which can help us to estimate the rate and effectiveness of the biodegradation. The subsequent research period includes the investigation of the method, testing its feasibility and adaptation in the environment. Last but not least, the research gives an opportunity to identify the producer of the contaminant based on the stable isotope composition of the contaminant.

  15. Experimental evaporation of hyperacid brines: Effects on chemical composition and chlorine isotope fractionation

    Science.gov (United States)

    Rodríguez, Alejandro; van Bergen, Manfred J.; Eggenkamp, H. G. M.

    2018-02-01

    Hyperacid brines from active volcanic lakes are some of the chemically most complex aqueous solutions on Earth. Their compositions provide valuable insights into processes of elemental transfer from a magma body to the surface and interactions with solid rocks and the atmosphere. This paper describes changes in chemical and δ37Cl signatures observed in a 1750 h isothermal evaporation experiment on hyperacid (pH 0.1) sulphate-chloride brine water from the active lake of Kawah Ijen volcano (Indonesia). Although gypsum was the only evaporite mineral identified in the evolving brine, decreasing Si concentrations may ultimately result in amorphous silica precipitation. Geochemical simulations predict the additional formation of elemental sulphur at lower water activities (aH2O ≤ 0.65) that were not reached in the experiment. Absence of other sulphates and halides despite the high load of dissolved elements (initial TDS ca. 100 g/kg) can be attributed to increased solubility of metals, promoted by extensive formation of complexes between the variety of cations and the major anions (HSO4-, Cl-, F-) present. Chlorine deviations from a conservative behaviour point to losses of gaseous hydrogen chloride (HCl(g)) and consequently an increase in Br/Cl ratios. Chlorine isotope fractionation that accompanied the escape of HCl(g) showed a marked change in sign and magnitude in the course of progressive evaporation of the brine. The calculated factor of fractionation between HCl(g) and dissolved Cl for the initial interval (before 500 h) is positive (1000lnαHCl(g)-Cldiss. = + 1.55 ± 0.49‰to + 3.37 ± 1.11‰), indicating that, at first, the escaping HCl(g) was isotopically heavier than the dissolved Cl remaining in the brine. Conversely, fractionation shifted to the opposite direction in the subsequent interval (1000lnαHCl(g)-Cldiss. = 5.67 ± 0.17‰to - 5.64 ± 0.08‰), in agreement with values reported in literature. It is proposed that Cl isotopic fractionation in

  16. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes

    DEFF Research Database (Denmark)

    Palau, Jordi; Marchesi, Massimo; Chambon, Julie Claire Claudia

    2014-01-01

    is located in Spain with contamination resulting in groundwater concentrations of up to 50 mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon......, showed a wide range in δ13C values from − 15.6 to − 40.5‰ for TCE and from − 18.5 to − 32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the δ37Cl values for TCE...

  17. Chlorine-36 investigations of salt lakes

    International Nuclear Information System (INIS)

    Chivas, A.R.; Kiss, E.

    1987-01-01

    The first chlorine-36 measurements are reported for surficial halite in lakes from a west-to-east traverse in Western Australia and from Lake Amadeus NT. Measurements of chlorine-36 were made using a 14 MV tandem accelerator. Isotopic chlorine ratios ranged from 8 to 53 x 10 exp-15, with no clear evidence for bomb-spike chlorine-36. The Western Australian samples have values close to secular equilibrium values for typical granite and groundwaters in this rock type. Studies are aimed at calculating the residence time of chloride in the surficial environment. 1 tab

  18. 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.

  19. Carbon isotope fractionation of chlorinated ethenes during oxidation by Fe{sup 2+} activated persulfate

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, Massimo, E-mail: m2marche@uwaterloo.ca [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Barcelona, Catalunya 08028 (Spain); Earth and Environmental Department, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Aravena, Ramon [Earth and Environmental Department, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Sra, Kanwartej S. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Golder Associates Inc, Toronto, Ontario, Canada L5N 5Z7 (Canada); Thomson, Neil R. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (Canada); Otero, Neus; Soler, Albert [Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Barcelona, Catalunya 08028 (Spain); Mancini, Silvia [Golder Associates Inc, Toronto, Ontario, Canada L5N 5Z7 (Canada)

    2012-09-01

    The increased use of persulfate (S{sub 2}O{sub 8}{sup 2-}) for in situ chemical oxidation to treat groundwater and soils contaminated by chlorinated hydrocarbon compounds (CHCs) requires unbiased methods to assess treatment performance. Stable carbon isotope analysis offers a potential tool for assessing the in situ treatment performance of persulfate at sites contaminated with CHCs. This study investigated the extent of C isotope fractionation during oxidation of tetrachloroethene (PCE), trichloroethene (TCE) and cis-dichloroethene (cis-DCE) by persulfate activated by ferrous ion (Fe{sup 2+}). An average carbon isotope enrichment factor {epsilon}{sub bulk} of - 4.9 Per-Mille-Sign for PCE, - 3.6 Per-Mille-Sign for TCE and - 7.6 Per-Mille-Sign for cis-DCE were obtained in batch experiments. Variations in the initial S{sub 2}O{sub 8}{sup 2-}/Fe{sup 2+}/CHC molar ratios did not result in any significant differences in carbon isotope fractionation. The occurrence of carbon isotope fractionation during oxidation and the lack of dependence of enrichment factors upon the S{sub 2}O{sub 8}{sup 2-}/Fe{sup 2+}/CHC molar ratio demonstrate that carbon isotope analysis can potentially be used at contaminated sites as an additional technique to estimate treatment efficacy during oxidation of CHCs by Fe{sup 2+} activated persulfate. Highlights: Black-Right-Pointing-Pointer The performance of in situ chemical oxidation (ISCO) is still difficult to assess. Black-Right-Pointing-Pointer We investigated the potential of carbon isotope analysis as a new assessing tool. Black-Right-Pointing-Pointer C isotope of PCE, TCE and DCE oxidized by persulfate activated by Fe{sup 2+} was measured. Black-Right-Pointing-Pointer Enrichment factors of - 4.9 Per-Mille-Sign for PCE, - 3.6 Per-Mille-Sign for TCE and - 7.6 Per-Mille-Sign for cisDCE were obtained. Black-Right-Pointing-Pointer Carbon isotope can potentially be used to estimate the ISCO treatment efficacy.

  20. Compound-specific chlorine isotope ratios of TCE, PCE and DCE isomers by direct injection using CF-IRMS

    International Nuclear Information System (INIS)

    Shouakar-Stash, Orfan; Drimmie, Robert J.; Zhang Min; Frape, Shaun K.

    2006-01-01

    A method for determining compound-specific Cl isotopic compositions (δ 37 Cl) was developed for tetrachloroethene (PCE), trichloroethene (TCE), cis-dichloroethene (cis-DCE), trans-dichloroethene (trans-DCE) and 1,1-dichloroethene (1,1-DCE). The isotope ratio mass spectrometry (IRMS) used in this study has nine collectors, including two for m/z 50 and 52 (CH 3 Cl) and two for m/z 94 and 96 (CH 3 Br). The development of this method is based on the fact that fragments with mass ratios of 94/96, 95/97 and 96/98 are produced from PCE, TCE and DCE isomers during ion bombardment in the source of a mass spectrometer. Using continuous flow isotope ratio mass spectrometry coupled with gas chromatography (GC-CF-IRMS), it is possible to separate these compounds on-line and directly measure the Cl isotopic ratios of the fragments with the specific mass ratios. Both pure phase and aqueous samples were used for Cl isotopic analysis. For pure phase samples, a vapour phase of the chlorinated ethenes was injected directly into the GC, whereas the solid phase micro extraction (SPME) method was used to extract these compounds from aqueous solutions. The precisions of this analytical technique were ±0.12 per mille (1σ, n = 30), ±0.06 per mille (1σ, n = 30), and ±0.08 per mille (1σ, n = 15) for PCE, TCE and DCE isomers, respectively. The limits of quantification (LOQ) for analyzing Cl isotopic composition in aqueous solutions were 20, 5, and 5 μg/L for PCE, TCE and DCE isomers, respectively. This corresponds to 6-9 nano-mole of Cl, which is approximately 80 times lower than the most sensitive existing method. Compared to methods previously available, this new development offers the following advantages: (1) The much lower LOQ make it possible to extract these compounds directly from aqueous solutions using SPME without pre-concentration; (2) The linking of a GC with an IRMS eliminates off-line separation; and (3) Because the fragments used for isotopic ratio measurement are

  1. Stable chlorine isotope compositions in waters from the Kusatsu-Shirane volcanic system, Japan

    International Nuclear Information System (INIS)

    Musashi, Masaaki

    1999-01-01

    Chlorine stable isotope compositions (δ 37 Cl, per-mil: per mille, vs. a standard sea water, SMOC) of six waters collected in 1984 from Kusatsu area (three springs), Manza area (two springs), and a crater lake Yugama, in the Kusatsu-Shirane volcanic system, Japan, are analysed with the overall precision of 0.12 per mille (2σ). The δ 37 Cl values range between -0.05 per mille and +0.20 per mille (the mean, +0.04 per mille), and are nearly equal to that of the sea water. And the values are not significantly different between the Kusatsu and Manza areas, although their thermal features have a strong chemical and geological variations with a geographical separation of over 8 km between the two areas. (author)

  2. Reactive transport modeling of chemical and isotope data to identify degradation processes of chlorinated ethenes in a diffusion-dominated media

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Damgaard, Ida; Jeannottat, Simon

    . Degradation and transport processes of chlorinated ethenes are not well understood in such geological settings, therefore risk assessment and remediation at these sites are particularly challenging. In this work, a combined approach of chemical and isotope analysis on core samples, and reactive transport...... the source zone (between 6 and 12 mbs). Concentrations and stable isotope ratios of the mother compounds and their daughter products, as well as redox parameters, fatty acids and microbial data, were analyzed with discrete sub-sampling along the cores. More samples (each 5 mm) were collected around...... of dechlorination and degradation pathways (biotic reductive dechlorination or abiotic β-elimination with iron minerals) in three core profiles. The model includes diffusion in the matrix, sequential reductive dechlorination, abiotic degradation, isotope fractionation due to degradation and due to diffusion...

  3. Monitoring biodegradation of ethene and bioremediation of chlorinated ethenes at a contaminated site using compound-specific isotope analysis (CSIA).

    Science.gov (United States)

    Mundle, Scott O C; Johnson, Tiffany; Lacrampe-Couloume, Georges; Pérez-de-Mora, Alfredo; Duhamel, Melanie; Edwards, Elizabeth A; McMaster, Michaye L; Cox, Evan; Révész, Kinga; Sherwood Lollar, Barbara

    2012-02-07

    Chlorinated ethenes are commonly found in contaminated groundwater. Remediation strategies focus on transformation processes that will ultimately lead to nontoxic products. A major concern with these strategies is the possibility of incomplete dechlorination and accumulation of toxic daughter products (cis-1,2-dichloroethene (cDCE), vinyl chloride (VC)). Ethene mass balance can be used as a direct indicator to assess the effectiveness of dechlorination. However, the microbial processes that affect ethene are not well characterized and poor mass balance may reflect biotransformation of ethene rather than incomplete dechlorination. Microbial degradation of ethene is commonly observed in aerobic systems but fewer cases have been reported in anaerobic systems. Limited information is available on the isotope enrichment factors associated with these processes. Using compound-specific isotope analysis (CSIA) we determined the enrichment factors associated with microbial degradation of ethene in anaerobic microcosms (ε = -6.7‰ ± 0.4‰, and -4.0‰ ± 0.8‰) from cultures collected from the Twin Lakes wetland area at the Savannah River site in Georgia (United States), and in aerobic microcosms (ε = -3.0‰ ± 0.3‰) from Mycobacterium sp. strain JS60. Under anaerobic and aerobic conditions, CSIA can be used to determine whether biotransformation of ethene is occurring in addition to biodegradation of the chlorinated ethenes. Using δ(13)C values determined for ethene and for chlorinated ethenes at a contaminated field site undergoing bioremediation, this study demonstrates how CSIA of ethene can be used to reduce uncertainty and risk at a site by distinguishing between actual mass balance deficits during reductive dechlorination and apparent lack of mass balance that is related to biotransformation of ethene.

  4. Chlorine Isotopic Composition of Perchlorate in Human Urine as a Means of Distinguishing Among Natural and Synthetic Exposure Sources

    Science.gov (United States)

    Poghosyan, Armen; Morel-Espinosa, Maria; Valentín-Blasini, Liza; Blount, Benjamin C.; Ferreccio, Catterina; Steinmaus, Craig M.; Sturchio, Neil C.

    2015-01-01

    Perchlorate (ClO4−) is a ubiquitous environmental contaminant with high human exposure potential; it has both natural and man-made sources in the environment. Natural perchlorate forms in the atmosphere from where it deposits onto the surface of Earth, whereas synthetic perchlorate is manufactured as an oxidant for industrial, aerospace, and military applications. Perchlorate exposure can potentially cause adverse health effects in humans by interfering with the production of thyroid hormones through competitively blocking iodide uptake. To control and reduce perchlorate exposure, the contributions of different sources of perchlorate exposure need to be quantified. Thus, we demonstrate a novel approach for determining the contribution of different perchlorate exposure sources by quantifying stable and radioactive chlorine isotopes of perchlorate extracted from composite urine samples from two distinct populations: one in Atlanta, USA and one in Taltal, Chile (Atacama region). Urinary perchlorate from the Atlanta region resembles indigenous natural perchlorate from the southwestern USA [δ37Cl = +4.1 ± 1.0 ‰; 36Cl/Cl = 1811 (± 136) × 10−15], and urinary perchlorate from the Taltal, Chile region is similar to natural perchlorate in nitrate salt deposits from the Atacama Desert of northern Chile [δ37Cl = −11.0 ± 1.0 ‰; 36Cl/Cl = 254 (± 40) × 10−15]. Neither urinary perchlorate resembled the isotopic pattern found in synthetic perchlorate. These results indicate that natural perchlorate of regional provenance is the dominant exposure source for the two sample populations, and that chlorine isotope ratios provide a robust tool for elucidating perchlorate exposure pathways. PMID:25805252

  5. Solvent effects on the kinetics of the chlorine isotopic exchange reaction between chloride ion and O,O-diphenyl phosphorochloridate or O,O-diphenyl phosphorchloridothioate

    International Nuclear Information System (INIS)

    Mikolajczyk, M.; Slebocka-Tilk, H.; Reimschussel, W.

    1982-01-01

    The effect of solvent on the kinetics of the chlorine isotopic exchange reaction between 36 Cl- ions and O,O-diphenyl phosphorochloridate or O,O-diphenyl phosphorochloridothioate has been investigated in nitromethane, acetonitrile, propylene carbonate, benzonitrile, nitrobenzene, and hexamethyl-phosphoric triamide. The rate constants decrease with increasing electrophilicity of the solvent. A good correlation between the logarithm of the rate constants and acceptor number (AN) of the solvent was obtained with identical slopes for reactions with phosphoryl and thiophosporyl compounds. The slopes for the dependence of ΔH or TΔS vs. AN for chlorine isotopic exchange in (PHO) 2 pace are opposite those for the exchange reaction in (PHO) 2 PSCl, so a constant ratio of k/sub p=O//k/sub p=s/ is observed, resulting from compensation of ΔH by ΔS. The effect of solvent on the initial state (from solubility measurements) and the transition state of the reaction between (PhO) 2 PSCl and the Cl- ion was evaluated. Changes of solvation of (PHO) 2 PSCE have practically no effect on the kinetics of the reactions. Changes of solvation of the chloride ion and of the transition state primarily influence the rate constants and activation parameters of the investigated isotopic-exchange reaction

  6. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    A method for quantitative measurement of 3-monochlorotyrosine and 3,5-dichlorotyrosine in insect cuticles is described, and it is used for determination of their distribution in various cuticular regions in nymphs and adults of the desert locust, Schistocerca gregaria. The two chlorinated tyrosine......, not-yet sclerotized cuticle of adult femur and tibia, the amounts increased rapidly during the first 24 h after ecdysis and more slowly during the next two weeks. Control analyses using stable isotope dilution mass spectrometry have confirmed that the chlorinated tyrosines are not artifacts formed...

  7. 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.

  8. Identification of chlorinated solvents degradation zones in clay till by high resolution chemical, microbial and compound specific isotope analysis

    DEFF Research Database (Denmark)

    Damgaard, Ida; Bjerg, Poul Løgstrup; Bælum, Jacob

    2013-01-01

    subsampling of the clay till cores. The study demonstrates that an integrated approach combining chemical analysis, molecular microbial tools and compound specific isotope analysis (CSIA) was required in order to document biotic and abiotic degradations in the clay till system. © 2013 Elsevier B.V.......The degradation of chlorinated ethenes and ethanes in clay till was investigated at a contaminated site (Vadsby, Denmark) by high resolution sampling of intact cores combined with groundwater sampling. Over decades of contamination, bioactive zones with degradation of trichloroethene (TCE) and 1...

  9. Calculation of carbon-14, chlorine-37, and deuterium kinetic isotope effects in the solvolysis of tert-butyl chloride

    International Nuclear Information System (INIS)

    Burton, G.W.; Sims, L.B.; Wilson, J.C.; Fry, A.

    1977-01-01

    In the solvolysis of tert-butyl chloride, satisfactory α-carbon-14, β-deuterium, and chlorine kinetic isotope effects (KIE) may be calculated for a productlike transition state characterized by bond orders n/sub C Cl/ = 0.2, n/sub C C/ = 1.18, and n/sub C H/ = 0.94, employing a diagonal valence force field, provided that allowance is made for hydrogen-bonded solvation of the developing chloride ion with n/sub Cl H/ approx. 0.05 (approx. 7 kcal/mole hydrogen bonds). The effect of the three solvating molecules appears to be to increase the ''effective'' mass of the incipient chloride ion and to decrease the loss of zero-point energy in going to the transition state. Reaction coordinates more complicated than a simple heterolysis of the carbon-chlorine bond appear to be unnecessary and there is no advantage in employing force fields more complex than a simple valence force field containing only diagonal elements for both the reactant and the transition state model. The structural and bonding features of the proposed transition state are in accord with earlier more qualitative conclusions concerning the polar nature and productlike character of the transition state, and provide a reasonable explanation of the kinetic and equilibrium isotope effects (EIE) for the reaction. An alternative transition state model involving weak solvent nucleophilic assistance provides reasonable calculated values for the KIE, but the EIE strongly suggest the importance of solvation of the leaving group which, together with the hyperconjugation of the β hydrogens, provides a preferred explanation of the tert-butyl solvolysis results

  10. Evaluation of perchlorate sources in the Rialto-Colton and Chino California subbasins using chlorine and oxygen isotope ratio analysis

    Science.gov (United States)

    Hatzinger, Paul B.; Böhlke, John Karl; Izbicki, John; Teague, Nicholas F.; Sturchio, Neil C.

    2015-01-01

    Perchlorate (ClO4-) in groundwater can be from synthetic or natural sources, the latter of which include both historical application of imported nitrate fertilizers from the Atacama Desert of Chile and naturally deposited ClO4- that forms atmospherically and accumulates in arid regions such as the southwestern US. The objective of this study was to evaluate the use of isotopic data to distinguish sources of ClO4- in groundwater in a specific region of the Rialto-Colton and Chino, CA groundwater subbasins (Study Area). This region includes two groundwater ClO4- plumes emanating from known military/industrial source areas, and a larger area outside of these plumes having measurable ClO4-. Perchlorate extracted from wells in this region was analyzed for chlorine and oxygen stable isotope ratios (δ37Cl, δ18O, δ17O) and radioactive chlorine-36 (36Cl) isotopic abundance, along with other geochemical, isotopic, and hydrogeologic data. Isotope data indicate synthetic, Atacama, and indigenous natural ClO4- were present in the Study Area. Stable isotope data from nearly all sampled wells within the contours of the two characterized plumes, including those located in a perched zone and within the regional groundwater aquifer, were consistent with a dominant synthetic ClO4- source. In wells downgradient from the synthetic plumes and in the Chino subbasin to the southwest, isotopic data indicate the dominant source of ClO4- largely was Atacama, presumably from historical application of nitrate fertilizer in this region. Past agricultural land use and historical records are consistent with this source being present in groundwater. The 36Cl and δ18O data indicate that wells having predominantly synthetic or Atacama ClO4- also commonly contained small fractions of indigenous natural ClO4-. The indigenous ClO4- was most evident isotopically in wells having the lowest overall ClO4- concentrations (< 1 μg/L), consistent with its occurrence as a low-level background constituent

  11. C, Cl and H compound-specific isotope analysis to assess natural versus Fe(0) barrier-induced degradation of chlorinated ethenes at a contaminated site

    Energy Technology Data Exchange (ETDEWEB)

    Audí-Miró, Carme, E-mail: carmeaudi@ub.edu [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Cretnik, Stefan [Institute of Groundwater Ecology, Helmholtz Zentrum München-National Research Center for Environmental Health, Ingolstädter Landstrasse 1, D-85764 Neuherberg (Germany); Torrentó, Clara; Rosell, Mònica [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Shouakar-Stash, Orfan [Department of Earth & Environmental Sciences, 200 University Ave. W, N2L 3G1 Waterloo, Ontario (Canada); Otero, Neus [Grup de Mineralogia Aplicada i Medi Ambient, Departament de Cristal.lografia, Mineralogia i Dipòsits Minerals, Facultat de Geologia, Universitat de Barcelona (UB), Martí Franquès s/n, 08028, Barcelona (Spain); Palau, Jordi [Université de Neuchâtel, CHYN - Centre d' Hydrogéologie, Rue Emile-Argand 11, CH-2000 Neuchâtel (Switzerland); and others

    2015-12-15

    Highlights: • {sup 13}C to evaluate natural chlorinated ethenes biodegradation. • {sup 13}C to evaluate the efficiency of a zero-valent iron-permeable reactive barrier. • {sup 13}C-{sup 37}Cl to discriminate biotic from abiotic degradation of cis-dichloroethene. • {sup 13}C-{sup 37}Cl-{sup 2}H of cis-DCE and TCE to elucidate different contaminant sources. - Abstract: Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on (1) using {sup 13}C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; (2) using dual element {sup 13}C-{sup 37}Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and (3) using {sup 13}C-{sup 37}Cl-{sup 2}H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the {sup 13}C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element {sup 13}C-{sup 37}Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. {sup 2}H combined with {sup 13}C and {sup 37}Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ{sup 2}H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.

  12. C, Cl and H compound-specific isotope analysis to assess natural versus Fe(0) barrier-induced degradation of chlorinated ethenes at a contaminated site

    International Nuclear Information System (INIS)

    Audí-Miró, Carme; Cretnik, Stefan; Torrentó, Clara; Rosell, Mònica; Shouakar-Stash, Orfan; Otero, Neus; Palau, Jordi

    2015-01-01

    Highlights: • 13 C to evaluate natural chlorinated ethenes biodegradation. • 13 C to evaluate the efficiency of a zero-valent iron-permeable reactive barrier. • 13 C- 37 Cl to discriminate biotic from abiotic degradation of cis-dichloroethene. • 13 C- 37 Cl- 2 H of cis-DCE and TCE to elucidate different contaminant sources. - Abstract: Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on (1) using 13 C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; (2) using dual element 13 C- 37 Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and (3) using 13 C- 37 Cl- 2 H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the 13 C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element 13 C- 37 Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. 2 H combined with 13 C and 37 Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of δ 2 H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation.

  13. Experimental investigation of concentration and stable isotopes signals during organic contaminants back diffusion

    DEFF Research Database (Denmark)

    Jin, Biao; Nika, Chrysanthi-Elisabeth; Rolle, Massimo

    2017-01-01

    -dichloroethene (cis-DCE) as model contaminant and we investigated its back diffusion from an impermeable source into a permeable saturated layer, in which advection-dominated flow conditions were established. We used concentration and stable chlorine isotope measurements to investigate the plumes originated by cis...... and stable isotope gradients in the flow-through setup. In particular, steep concentration and stable isotope gradients were observed at the outlet. Lateral isotope gradients corresponding to chlorine isotope fractionation up to 20‰ were induced by cis-DCE back diffusion and subsequent advection......-dominated transport in all flow-through experiments. A numerical modeling approach, tracking individually all chlorine isotopologues, based on the accurate parameterization of local dispersion, as well as on the values of aqueous diffusion coefficients and diffusion-induced isotope fractionation from a previous study...

  14. Integrative approach to delineate natural attenuation of chlorinated benzenes in anoxic aquifers

    International Nuclear Information System (INIS)

    Stelzer, Nicole; Imfeld, Gwenael; Thullner, Martin; Lehmann, Juergen; Poser, Alexander; Richnow, Hans-H.; Nijenhuis, Ivonne

    2009-01-01

    Biodegradation of chlorobenzenes was assessed at an anoxic aquifer by combining hydrogeochemistry and stable isotope analyses. In situ microcosm analysis evidenced microbial assimilation of chlorobenzene (MCB) derived carbon and laboratory investigations asserted mineralization of MCB at low rates. Sequential dehalogenation of chlorinated benzenes may affect the isotope signature of single chlorobenzene species due to simultaneous depletion and enrichment of 13 C, which complicates the evaluation of degradation. Therefore, the compound-specific isotope analysis was interpreted based on an isotope balance. The enrichment of the cumulative isotope composition of all chlorobenzenes indicated in situ biodegradation. Additionally, the relationship between hydrogeochemistry and degradation activity was investigated by principal component analysis underlining variable hydrogeochemical conditions associated with degradation activity at the plume scale. Although the complexity of the field site did not allow straightforward assessment of natural attenuation processes, the application of an integrative approach appeared relevant to characterize the in situ biodegradation potential. - Lines of evidence for in situ biodegradation of chlorinated benzenes in an anoxic aquifer by combining hydrogeochemical and stable isotope data with multivariate statistics.

  15. Integrative approach to delineate natural attenuation of chlorinated benzenes in anoxic aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Stelzer, Nicole; Imfeld, Gwenael [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Thullner, Martin [Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Lehmann, Juergen [Ingenieurbuero Roth and Partner GmbH, Hans-Sachs-Str. 9, 76133 Karlsruhe (Germany); Poser, Alexander [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Richnow, Hans-H., E-mail: hans.richnow@ufz.d [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany); Nijenhuis, Ivonne [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, 04318 Leipzig (Germany)

    2009-06-15

    Biodegradation of chlorobenzenes was assessed at an anoxic aquifer by combining hydrogeochemistry and stable isotope analyses. In situ microcosm analysis evidenced microbial assimilation of chlorobenzene (MCB) derived carbon and laboratory investigations asserted mineralization of MCB at low rates. Sequential dehalogenation of chlorinated benzenes may affect the isotope signature of single chlorobenzene species due to simultaneous depletion and enrichment of {sup 13}C, which complicates the evaluation of degradation. Therefore, the compound-specific isotope analysis was interpreted based on an isotope balance. The enrichment of the cumulative isotope composition of all chlorobenzenes indicated in situ biodegradation. Additionally, the relationship between hydrogeochemistry and degradation activity was investigated by principal component analysis underlining variable hydrogeochemical conditions associated with degradation activity at the plume scale. Although the complexity of the field site did not allow straightforward assessment of natural attenuation processes, the application of an integrative approach appeared relevant to characterize the in situ biodegradation potential. - Lines of evidence for in situ biodegradation of chlorinated benzenes in an anoxic aquifer by combining hydrogeochemical and stable isotope data with multivariate statistics.

  16. Process for separating U isotopes by infrared excitation

    International Nuclear Information System (INIS)

    Lyon, R.K.; Kaldor, Andrew.

    1976-01-01

    This invention concerns a process for separating a substance into at least two parts in which the isotopic abundances of a given element differ from those of the isotopes of the substance prior to separation. Specifically, the invention concerns a process for the selective excitation of the isotopes of a gaseous phase UF 6 by absorption of infra-red photons, then by selective reaction of UF 6 excited with atomics chlorine, bromine or iodine, forming a product that may be separated by a standard method. The preference criteria of the atomic chlorine, bromine and iodine are related to the thermal dilution problem [fr

  17. Chlorine isotope constraints on fluid-rock interactions during subduction and exhumation of the Zermatt-Saas ophiolite

    Science.gov (United States)

    Selverstone, J.; Sharp, Z. D.

    2013-10-01

    Chlorine isotope compositions of high-pressure (˜2.3 GPa) serpentinite, rodingite, and hydrothermally altered oceanic crust (AOC) differ significantly from high- and ultrahigh-pressure (> 3.2 GPa) metasedimentary rocks in the Aosta region, Italy. Texturally early serpentinites, rodingites, and AOC have bulk δ37Cl values indistinguishable from those of modern seafloor analogues (δ37Cl = -1.0 to +1.0‰). In contrast, serpentinites and AOC samples that recrystallized during exhumation have low δ37Cl values (-2.7 to -0.5‰); 37Cl depletion correlates with progressive changes in bulk chemistry. HP/UHP metasediments have low δ37Cl values (median = -2.5‰) that differ statistically from modern marine sediments (median = -0.6‰). Cl in metasedimentary rocks is concentrated in texturally early minerals, indicating modification of seafloor compositions early in the subduction history. The data constrain fluid sources during both subduction and exhumation-related phases of fluid-rock interaction: (1) marine sediments at the top of the downgoing plate likely interacted with isotopically light pore fluids from the accretionary wedge in the early stages of subduction. (2) No pervasive interaction with externally derived fluid occurred during subsequent subduction to the maximum depths of burial. (3) Localized mixing between serpentinites and fluids released by previously isotopically modified metasediments occurred during exhumation in the subduction channel. Most samples, however, preserved protolith signatures during subduction to near-arc depths.

  18. Complementing approaches to demonstrate chlorinated solvent biodegradation in a complex pollution plume: Mass balance, PCR and compound-specific stable isotope analysis

    Science.gov (United States)

    Courbet, Christelle; Rivière, Agnès; Jeannottat, Simon; Rinaldi, Sandro; Hunkeler, Daniel; Bendjoudi, Hocine; de Marsily, Ghislain

    2011-11-01

    This work describes the use of different complementing methods (mass balance, polymerase chain reaction assays and compound-specific stable isotope analysis) to demonstrate the existence and effectiveness of biodegradation of chlorinated solvents in an alluvial aquifer. The solvent-contaminated site is an old chemical factory located in an alluvial plain in France. As most of the chlorinated contaminants currently found in the groundwater at this site were produced by local industries at various times in the past, it is not enough to analyze chlorinated solvent concentrations along a flow path to convincingly demonstrate biodegradation. Moreover, only a few data were initially available to characterize the geochemical conditions at this site, which were apparently complex at the source zone due to (i) the presence of a steady oxygen supply to the groundwater by irrigation canal losses and river infiltration and (ii) an alkaline pH higher than 10 due to former underground lime disposal. A demonstration of the existence of biodegradation processes was however required by the regulatory authority within a timeframe that did not allow a full geochemical characterization of such a complex site. Thus a combination of different fast methods was used to obtain a proof of the biodegradation occurrence. First, a mass balance analysis was performed which revealed the existence of a strong natural attenuation process (biodegradation, volatilization or dilution), despite the huge uncertainty on these calculations. Second, a good agreement was found between carbon isotopic measurements and PCR assays (based on 16S RNA gene sequences and functional genes), which clearly indicated reductive dechlorination of different hydrocarbons (Tetrachloroethene—PCE-, Trichloroethene—TCE-, 1,2- cisDichloroethene— cis-1,2-DCE-, 1,2- transDichloroethene— trans-1,2-DCE-, 1,1-Dichloroethene—1,1-DCE-, and Vinyl Chloride—VC) to ethene. According to these carbon isotope measurements

  19. Isotope separation process

    International Nuclear Information System (INIS)

    1976-01-01

    The invention relates to a process for separating a given material into two or more parts, in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in the said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase UF 6 by infrared photon absorption followed by selective reaction of said excited UF 6 with atomic chlorine, bromine, or iodine to form a product which may be separated by means known in the art

  20. Potential of isotope analysis (C, Cl) to identify dechlorination mechanisms

    Science.gov (United States)

    Cretnik, Stefan; Thoreson, Kristen; Bernstein, Anat; Ebert, Karin; Buchner, Daniel; Laskov, Christine; Haderlein, Stefan; Shouakar-Stash, Orfan; Kliegman, Sarah; McNeill, Kristopher; Elsner, Martin

    2013-04-01

    Chloroethenes are commonly used in industrial applications, and detected as carcinogenic contaminants in the environment. Their dehalogenation is of environmental importance in remediation processes. However, a detailed understanding frequently accounted problem is the accumulation of toxic degradation products such as cis-dichloroethylene (cis-DCE) at contaminated sites. Several studies have addressed the reductive dehalogenation reactions using biotic and abiotic model systems, but a crucial question in this context has remained open: Do environmental transformations occur by the same mechanism as in their corresponding in vitro model systems? The presented study shows the potential to close this research gap using the latest developments in compound specific chlorine isotope analysis, which make it possible to routinely measure chlorine isotope fractionation of chloroethenes in environmental samples and complex reaction mixtures.1,2 In particular, such chlorine isotope analysis enables the measurement of isotope fractionation for two elements (i.e., C and Cl) in chloroethenes. When isotope values of both elements are plotted against each other, different slopes reflect different underlying mechanisms and are remarkably insensitive towards masking. Our results suggest that different microbial strains (G. lovleyi strain SZ, D. hafniense Y51) and the isolated cofactor cobalamin employ similar mechanisms of reductive dechlorination of TCE. In contrast, evidence for a different mechanism was obtained with cobaloxime cautioning its use as a model for biodegradation. The study shows the potential of the dual isotope approach as a tool to directly compare transformation mechanisms of environmental scenarios, biotic transformations, and their putative chemical lab scale systems. Furthermore, it serves as an essential reference when using the dual isotope approach to assess the fate of chlorinated compounds in the environment.

  1. Synthetic strategies in the preparation of regiospecifically chlorine-37 labeled polychlorinated dibenzo-p-dioxins

    International Nuclear Information System (INIS)

    Mahiou, Belaid; Deinzer, M.L.

    1992-01-01

    A series of thirteen regiospecifically chlorine-37 labeled polychlorodibenzo-p-dioxins were synthesized via the Sandmeyer reaction. Nitrochlorodibenzodioxins which were obtained by a base promoted condensation of catechols and dinitropolyhalobenzenes were reduced and converted to the diazonium salts. Chlorine-37 was introduced using cuprous chloride-37. The isotopic enrichment was in the range 75-96%. (Author)

  2. Solvent and ion-pairing effects on the chlorine kinetic isotope effect of t-butyl chloride

    International Nuclear Information System (INIS)

    McCord, B.R.

    1986-01-01

    The solvolysis of t-butyl chloride and 1-adamantyl chloride was measured in mixtures of aqueous 2,2,2-trifluoroethanols and in mixtures of aqueous ethanols. The KIEs for t-butyl chloride at 25 0 C in 94% TFE/water, and 60% ethanol/water (solvent mixtures with similar polarity) were 1.0097 and 1.0104 respectively. Further investigations showed a KIE of 1.0104 in 50% ethanol/water and 1.0105 in 100% ethanol while the isotope effect in the fluorinated ethanols rose from 1.0094 in 99% TFE/water to 1.0101 in 70% ethanol/water. The KIE in all these solvents were shown to be directly proportional to the nucleophilicity of the solvent and indicates nucleophilic attack on an ion pair. The similar KIE of t-butyl chloride in the ethanol/water solvents was found to support the contention that solvent polarity exerts a minimal effect on the chlorine KIE

  3. Stable carbon isotope fractionation of chlorinated ethenes by a microbial consortium containing multiple dechlorinating genes.

    Science.gov (United States)

    Liu, Na; Ding, Longzhen; Li, Haijun; Zhang, Pengpeng; Zheng, Jixing; Weng, Chih-Huang

    2018-08-01

    The study aimed to determine the possible contribution of specific growth conditions and community structures to variable carbon enrichment factors (Ɛ- carbon ) values for the degradation of chlorinated ethenes (CEs) by a bacterial consortium with multiple dechlorinating genes. Ɛ- carbon values for trichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride were -7.24% ± 0.59%, -14.6% ± 1.71%, and -21.1% ± 1.14%, respectively, during their degradation by a microbial consortium containing multiple dechlorinating genes including tceA and vcrA. The Ɛ- carbon values of all CEs were not greatly affected by changes in growth conditions and community structures, which directly or indirectly affected reductive dechlorination of CEs by this consortium. Stability analysis provided evidence that the presence of multiple dechlorinating genes within a microbial consortium had little effect on carbon isotope fractionation, as long as the genes have definite, non-overlapping functions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Stable chlorine isotopes in arid non-marine basins: Instances and possible fractionation mechanisms

    International Nuclear Information System (INIS)

    Eastoe, C.J.

    2016-01-01

    Stable chlorine isotopes are useful geochemical tracers in processes involving the formation and evolution of evaporitic halite. Halite and dissolved chloride in groundwater that has interacted with halite in arid non-marine basins has a δ 37 Cl range of 0 ± 3‰, far greater than the range for marine evaporites. Basins characterized by high positive (+1 to +3‰), near-0‰, and negative (−0.3 to −2.6‰) are documented. Halite in weathered crusts of sedimentary rocks has δ 37 Cl values as high as +5.6‰. Salt-excluding halophyte plants excrete salt with a δ 37 Cl range of −2.1 to −0.8‰. Differentiated rock chloride sources exist, e.g. in granitoid micas, but cannot provide sufficient chloride to account for the observed data. Single-pass application of known fractionating mechanisms, equilibrium salt-crystal interaction and disequilibrium diffusive transport, cannot account for the large ranges of δ 37 Cl. Cumulative fractionation as a result of multiple wetting-drying cycles in vadose playas that produce halite crusts can produce observed positive δ 37 Cl values in hundreds to thousands of cycles. Diffusive isotope fractionation as a result of multiple wetting-drying cycles operating at a spatial scale of 1–10 cm can produce high δ 37 Cl values in residual halite. Chloride in rainwater is subject to complex fractionation, but develops negative δ 37 Cl values in certain situations; such may explain halite deposits with bulk negative δ 37 Cl values. Future field studies will benefit from a better understanding of hydrology and rainwater chemistry, and systematic collection of data for both Cl and Br. - Highlights: • δ 37 Cl in halite from arid, non-marine sedimentary basins ranges from −3 to +5.5‰. • Cl − in vadose playas may develop large isotope fractionation through cyclic wetting and drying. • Cl − in phreatic playas undergoes no fractionation as a result of cyclic wetting and drying. • Cl − in weathered

  5. Compound-Specific Isotope Analyses to Assess TCE Biodegradation in a Fractured Dolomitic Aquifer.

    Science.gov (United States)

    Clark, Justin A; Stotler, Randy L; Frape, Shaun K; Illman, Walter A

    2017-01-01

    The potential for trichloroethene (TCE) biodegradation in a fractured dolomite aquifer at a former chemical disposal site in Smithville, Ontario, Canada, is assessed using chemical analysis and TCE and cis-DCE compound-specific isotope analysis of carbon and chlorine collected over a 16-month period. Groundwater redox conditions change from suboxic to much more reducing environments within and around the plume, indicating that oxidation of organic contaminants and degradation products is occurring at the study site. TCE and cis-DCE were observed in 13 of 14 wells sampled. VC, ethene, and/or ethane were also observed in ten wells, indicating that partial/full dechlorination has occurred. Chlorine isotopic values (δ 37 Cl) range between 1.39 to 4.69‰ SMOC for TCE, and 3.57 to 13.86‰ SMOC for cis-DCE. Carbon isotopic values range between -28.9 and -20.7‰ VPDB for TCE, and -26.5 and -11.8‰ VPDB for cis-DCE. In most wells, isotopic values remained steady over the 15-month study. Isotopic enrichment from TCE to cis-DCE varied between 0 and 13‰ for carbon and 1 and 4‰ for chlorine. Calculated chlorine-carbon isotopic enrichment ratios (ϵ Cl /ϵ C ) were 0.18 for TCE and 0.69 for cis-DCE. Combined, isotopic and chemical data indicate very little dechlorination is occurring near the source zone, but suggest bacterially mediated degradation is occurring closer to the edges of the plume. © 2016, National Ground Water Association.

  6. Ecological impact of chloro-organics produced by chlorination of cooling tower waters

    International Nuclear Information System (INIS)

    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

  7. Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.

    Science.gov (United States)

    Heckel, Benjamin; Rodríguez-Fernández, Diana; Torrentó, Clara; Meyer, Armin; Palau, Jordi; Domènech, Cristina; Rosell, Mònica; Soler, Albert; Hunkeler, Daniel; Elsner, Martin

    2017-03-21

    Compound-specific chlorine isotope analysis of tetrachloromethane (CCl 4 ) and trichloromethane (CHCl 3 ) was explored by both, gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and GC-quadrupole MS (GC-qMS), where GC-qMS was validated in an interlaboratory comparison between Munich and Neuchâtel with the same type of commercial GC-qMS instrument. GC-IRMS measurements analyzed CCl isotopologue ions, whereas GC-qMS analyzed the isotopologue ions CCl 3 , CCl 2 , CCl (of CCl 4 ) and CHCl 3 , CHCl 2 , CHCl (of CHCl 3 ), respectively. Lowest amount dependence (good linearity) was obtained (i) in H-containing fragment ions where interference of 35 Cl- to 37 Cl-containing ions was avoided; (ii) with tuning parameters favoring one predominant rather than multiple fragment ions in the mass spectra. Optimized GC-qMS parameters (dwell time 70 ms, 2 most abundant ions) resulted in standard deviations of 0.2‰ (CHCl 3 ) and 0.4‰ (CCl 4 ), which are only about twice as large as 0.1‰ and 0.2‰ for GC-IRMS. To compare also the trueness of both methods and laboratories, samples from CCl 4 and CHCl 3 degradation experiments were analyzed and calibrated against isotopically different reference standards for both CCl 4 and CHCl 3 (two of each). Excellent agreement confirms that true results can be obtained by both methods provided that a consistent set of isotopically characterized reference materials is used.

  8. Chlorine Diffusion in Uranium Dioxide: Thermal Effects versus Radiation Enhanced Effects

    International Nuclear Information System (INIS)

    Pipon, Yves; Moncoffre, Nathalie; Bererd, Nicolas; Jaffrezic, Henri; Toulhoat, Nelly; Barthe, Marie France; Desgardin, Pierre; Raimbault, Louis; Scheidegger, Andre M.; Carlot, Gaelle

    2007-01-01

    Chlorine is present as an impurity in the UO 2 nuclear fuel. 35 Cl is activated into 36 Cl by thermal neutron capture. In case of interim storage or deep geological disposal of the spent fuel, this isotope is known to be able to contribute significantly to the instant release fraction because of its mobile behavior and its long half life (around 300000 years). It is therefore important to understand its migration behavior within the fuel rod. During reactor operation, chlorine diffusion can be due to thermally activated processes or can be favoured by irradiation defects induced by fission fragments or alpha decay. In order to decouple both phenomena, we performed two distinct experiments to study the effects of thermal annealing on the behaviour of chlorine on one hand and the effects of the irradiation with fission products on the other hand. During in reactor processes, part of the 36 Cl may be displaced from its original position, due to recoil or to collisions with fission products. In order to study the behavior of the displaced chlorine, 37 Cl has been implanted into sintered depleted UO 2 pellets (mean grain size around 18 μm). The spatial distribution of the implanted and pristine chlorine has been analyzed by SIMS before and after treatment. Thermal annealing of 37 Cl implanted UO 2 pellets (implantation fluence of 10 13 ions.cm -2 ) show that it is mobile from temperatures as low as 1273 K (E a =4.3 eV). The irradiation with fission products (Iodine, E=63.5 MeV) performed at 300 and 510 K, shows that the diffusion of chlorine is enhanced and that a thermally activated contribution is preserved (E a =0.1 eV). The diffusion coefficients measured at 1473 K and under fission product irradiation at 510 K are similar (D = 3.10 -14 cm 2 .s -1 ). Considering in first approximation that the diffusion length L can be expressed as a function of the diffusion coefficient D and time t by : L=(Dt)1/2, the diffusion distance after 3 years is L=17 μm. It results that

  9. Analysis of nitrosamines in water by automated SPE and isotope dilution GC/HRMS Occurrence in the different steps of a drinking water treatment plant, and in chlorinated samples from a reservoir and a sewage treatment plant effluent.

    Science.gov (United States)

    Planas, Carles; Palacios, Oscar; Ventura, Francesc; Rivera, Josep; Caixach, Josep

    2008-08-15

    A method based on automated solid-phase extraction (SPE) and isotope dilution gas chromatography/high resolution mass spectrometry (GC/HRMS) has been developed for the analysis of nine nitrosamines in water samples. The combination of automated SPE and GC/HRMS for the analysis of nitrosamines has not been reported previously. The method shows as advantages the selectivity and sensitivity of GC/HRMS analysis and the high efficiency of automated SPE with coconut charcoal EPA 521 cartridges. Low method detection limits (MDLs) were achieved, along with a greater facility of the procedure and less dependence on the operator with regard to the methods based on manual SPE. Quality requirements for isotope dilution-based methods were accomplished for most analysed nitrosamines, regarding to trueness (80-120%), method precision (water samples (16 samples from a drinking water treatment plant {DWTP}, 2 chlorinated samples from a sewage treatment plant {STP} effluent, and 1 chlorinated sample from a reservoir) were analysed. Concentrations of nitrosamines in the STP effluent were 309.4 and 730.2 ng/L, being higher when higher doses of chlorine were applied. N-Nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were the main compounds identified in the STP effluent, and NDEA was detected above 200 ng/L, regulatory level for NDMA in effluents stated in Ontario (Canada). Lower concentrations of nitrosamines were found in the reservoir (20.3 ng/L) and in the DWTP samples (n.d. -28.6 ng/L). NDMA and NDEA were respectively found in the reservoir and in treated and highly chlorinated DWTP samples at concentrations above 10 ng/L (guide value established in different countries). The highest concentrations of nitrosamines were found after chlorination and ozonation processes (ozonated, treated and highly chlorinated water) in DWTP samples.

  10. Mass Spectrometry Identification of N-Chlorinated Dipeptides in Drinking Water.

    Science.gov (United States)

    Huang, Guang; Jiang, Ping; Li, Xing-Fang

    2017-04-04

    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.

  11. Comparison between PGAA and ID-AMS analysis for determining chlorine content in whole rock basalt

    Science.gov (United States)

    di Nicola, L.; Schnabel, C.; Wilcken, K. M.; Gméling, K.

    2009-04-01

    Accurate determination of chlorine concentrations in terrestrial rocks is of importance for the interpretation of terrestrial in-situ cosmogenic 36Cl. Neutron capture by 35Cl, together with production from Ca and K, is one of the three major production pathways of 36Cl in rocks. Here, we present an inter-comparison of chlorine determinations by two procedures. The first approach is an independent Cl determination by prompt gamma (neutron) activation analysis (PGAA). The second method is isotope dilution based on isotopically-enriched stable chlorine carrier added during chemical sample preparation for accelerator mass spectrometry (ID-AMS). Twenty six (26) whole rock samples have been processed for PGAA and ID-AMS analyses. Elemental analysis by PGAA provides concentrations of major, minor and trace elements including the target elements for 36Cl production (K, Ca, Ti, and Fe), as well as of neutron absorbers and neutron moderators (H, B, Cl, Sm and Gd). The Cl concentrations determined during this study constitute the first inter-comparison for concentrations below 100 μCl/g. Our results show no significant difference in Cl concentrations between methods, and comparable uncertainties. This agreement guarantees that during the procedure we employ for whole rock sample no significant loss of stable chlorine from either the spike or the sample occurs before isotopic equilibration, prior to AgCl precipitation. Furthermore, we show that the elemental analysis by PGAA offers anadvance for the interpretation of 36Cl measurements. It allows simultaneous measurement of major and most trace element concentrations with a precision necessary for calculating the relative contributions to 36Cl production rates of the different mechanisms. Finally, the Cl concentration can be used to optimize the amount of isotopically-enriched spike for AMS-ID sample preparation for 36Cl.

  12. Applications of compound-specific carbon isotope ratios in organic contaminant studies

    International Nuclear Information System (INIS)

    Aravena, R.; Hunkeler, D.; Bloom, Y.; Frape, S.K.; Butler, B.; Edwards, E.; Cox, E.

    1999-01-01

    In this paper results are presented on the application of compound-specific isotope ratios measurements to assess biodegradation of chlorinated solvents, in particularly on microbial dechlorination of tetrachloroethene (PCE) and trichloroethene (TCE). Analytical aspects and isotope data from laboratory and field studies are discussed. The analytical tests showed that both headspace and SPME techniques provide accurate δ 13 C values with a similar precision for a wide range of chlorinated solvents. However, the SPME method is generally more sensitive. The microcosm experiments show that a significant isotopic fractionation occurs during dechlorination of PCE and TCE to ethene. The largest fractionation factors are observed in the steps DCE-VC and VC-Ethene. In general, the δ 13 C of each dechlorination product was always more negative than the δ 13 C of the corresponding precursor. In addition, the δ 13 C values of each compound increased with time. A similar pattern was observed for dechlorination of PCE at a field site. These results show that compound-specific carbon isotope ratios technology is a very sensitive tool for evaluation of natural attenuation of chlorinated solvents in groundwater. (author)

  13. Chlorine Isotope Evidence for Syn-Subduction Modification of Serpentinites by Interaction with Sediment-Derived Fluid

    Science.gov (United States)

    Selverstone, J.; Sharp, Z. D.

    2012-12-01

    High-pressure serpentinites and rodingites and high- to ultrahigh-pressure metasedimentary rocks from the Aosta region, Italy, preserve strikingly different chlorine isotope compositions that can be used to constrain the nature of fluid-rock interactions during subduction. Serpentinites and rodingitized gabbroic dikes subducted to 70-80 km have bulk δ37Cl values between -1.6 and +0.9‰ (median= -0.5‰, n=26 plus 5 replicates; one amphibole-vein outlier at -2.9‰). Serpentinite δ37Cl values are positively correlated with Cr ± Cl contents (r2= 0.97 and 0.58) and negatively correlated with CaO (r2=0.72). BSE imaging and X-ray mapping reveal up to three generations of compositionally distinct serpentine and chlorite in single samples. The youngest generation, which is most abundant, has the lowest chlorine content. Three rodingite samples contain abundant texturally early fluid inclusions. These samples were finely crushed and leached in 18 MΩ H2O to extract water-soluble chlorides. The leachates, which are assumed to record the compositions of the fluid inclusions, have δ37Cl values that are 0.7-1.5‰ lower than the corresponding bulk rock values. Leachate from the outlier amph-magnesite vein is indistinguishable from the bulk value at -2.7‰. There is almost no overlap between the Cl isotope compositions of HP serp/rod samples and associated HP/UHP metasedimentary rocks. Calcmica schists, diamond-bearing Mn nodules, and impure marbles subducted to >130 km and calcmica schists and Mn crusts transported to 70-80 km have δ37Cl values between -4.5 and -1.5‰ (median= -2.7‰, n=25 plus 7 replicates; two outlier points at -0.5‰). Primary fluid inclusions in the diamondiferous samples contain carbonate- and silicate-bearing aqueous fluids with very low chloride contents (Frezzotti et al., 2011, Nature Geosci). Taken together, these data record a history of progressive modification of serpentinites and rodingites by mixing with low-δ37Cl, low-Cl, high

  14. Laser-induced photochemical enrichment of boron isotopes

    International Nuclear Information System (INIS)

    Freund, S.M.; Ritter, J.J.

    1976-01-01

    A boron trichloride starting material containing both boron-10 isotopes and boron-11 isotopes is selectively enriched in one or the other of these isotopes by a laser-induced photochemical method involving the reaction of laser-excited boron trichloride with either H 2 S or D 2 S. The method is carried out by subjecting a low pressure gaseous mixture of boron trichloride starting material and the sulfide to infrared radiation from a carbon dioxide TE laser. The wave length of the radiation is selected so as to selectively excite one or the other of boron-10 BCl 3 molecules or boron-11 BCl 3 molecules, thereby making them preferentially more reactive with the sulfide. The laser-induced reaction produces both a boron-containing solid phase reaction product and a gaseous phase containing mostly unreacted BCl 3 and small amounts of sulfhydroboranes. Pure boron trichloride selectively enriched in one of the isotopes is recovered as the primary product of the method from the gaseous phase by a multi-step recovery procedure. Pure boron trichloride enriched in the other isotope is recovered as a secondary product of the method by the subsequent chlorination of the solid phase reaction product followed by separation of BCl 3 from the mixture of gaseous products resulting from the chlorination

  15. Radiochemical analysis of chlorine-36

    International Nuclear Information System (INIS)

    Rodriguez, M.; Pina, G.; Lara, E.

    2006-01-01

    The radioactive chlorine isotope, 36 Cl, decays with a half-life of 3x10 5 years by emitting a beta particle (98 %) and by electron capture. The aim of this paper is to propose a radiochemical separation method of 36 Cl from the other beta-gamma emitters present in low and medium radioactive wastes such as spent ion exchange resins and evaporator concentrates, that arise from Nuclear Power Plants and particularly in the wastes that come from decommissioning activities of graphite reactors, in order to provide data for 36 Cl inventory calculations. The separation method proposed is based on an oxidation technique where chlorine is trapped by NaOH. 36 Cl beta emissions are measured by liquid scintillation counting by the dual label technique in order to avoid the contamination produced by 14 C which is also trapped by NaOH and which is the main contaminant present in graphite samples. The sensitivity of this method is sufficient to achieve the needed thresholds for the radiological characterization of the radioactive materials to which this method can be applied. (author)

  16. Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

    Directory of Open Access Journals (Sweden)

    F. Keppler

    2018-05-01

    Full Text Available Chloromethane (CH3Cl is an important provider of chlorine to the stratosphere but detailed knowledge of its budget is missing. Stable isotope analysis is a potentially powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog chamber at 293 ± 1 K. We measured the stable hydrogen isotope values of the unreacted CH3Cl using compound-specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −264±45 and −280±11 ‰, respectively. For comparison, we performed similar experiments using methane (CH4 as the target compound with OH and obtained a fractionation constant of −205±6 ‰ which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

  17. Studies with solid chlorine chemical for chlorination of sea water systems

    International Nuclear Information System (INIS)

    Sankar, N.; Kumaraswamy, P.; Santhanam, V.S.; Jeena, P.; Hari Krishna, K.; Rajendran, D.

    2015-01-01

    Chlorination is one of the conventional methods to control biofouling of condenser cooling water systems using either river water, reservoir water or sea water. However, there are many safety concerns associated with handling, storage and application of gaseous chlorine. Studies were carried out with suitable alternative chlorine chemical compounds which do not involve majority of these concerns but meet the functional requirement of gas chlorine. Trichloroisocyanuric Acid (TCCA) is one of the suitable alternatives to Gas chlorine. TCCA is a chlorine stabilized compound, stabilized with Cyanuric acid, thus similar to Gas Chlorine in its functions except that it is available in solid form. Release of chlorine is a gradual process in TCCA unlike Gaseous chlorine. Field studies with TCCA indicated gradual and near uniform release rate of chlorine, for longer duration with the requisite free residual chlorine levels (FRC). Thus, use of TCCA could be considered as a suitable alternative for gas chlorine for regular chlorination requirements. (author)

  18. {sup 37}Cl, {sup 15}N, {sup 13}C isotopic analysis of common agro-chemicals for identifying non-point source agricultural contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Annable, W.K. [Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)]. E-mail: wkannabl@uwaterloo.ca; Frape, S.K. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Shouakar-Stash, O. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Shanoff, T. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Drimmie, R.J. [Department of Earth Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Harvey, F.E. [School of Natural Resources, University of Nebraska, Lincoln, NE 68588-0517 (United States)

    2007-07-15

    The isotopic compositions of commercially available herbicides were analyzed to determine their respective {sup 15}N, {sup 13}C and {sup 37}Cl signatures for the purposes of developing a discrete tool for tracing and identifying non-point source contaminants in agricultural watersheds. Findings demonstrate that of the agrochemicals evaluated, chlorine stable isotopes signatures range between {delta}{sup 37}Cl = -4.55 per mille and +3.40 per mille , whereas most naturally occurring chlorine stable isotopes signatures, including those of road salt, sewage sludge and fertilizers, vary in a narrow range about the Standard Mean Ocean Chloride (SMOC) between -2.00 per mille and +1.00 per mille . Nitrogen stable isotope values varied widely from {delta}{sup 15}N = -10.86 per mille to +1.44 per mille and carbon stable isotope analysis gave an observed range between {delta}{sup 13}C = -37.13 per mille and -21.35 per mille for the entire suite of agro-chemicals analyzed. When nitrogen, carbon and chlorine stable isotope analyses were compared in a cross-correlation analysis, statistically independent isotopic signatures exist suggesting a new potential tracer tool for identifying herbicides in the environment.

  19. Stable Isotope Systematics of Martian Perchlorate

    Science.gov (United States)

    Martin, P.; Farley, K. A.; Archer, D., Jr.; Atreya, S. K.; Conrad, P. G.; Eigenbrode, J. L.; Fairen, A.; Franz, H. B.; Freissinet, C.; Glavin, D. P.; Mahaffy, P. R.; Malespin, C.; Ming, D. W.; Navarro-Gonzalez, R.; Sutter, B.

    2015-12-01

    Chlorine isotopic compositions in HCl released during evolved gas analysis (EGA) runs have been detected by the Sample Analysis at Mars (SAM) instrument on the Curiosity rover ranging from approximately -9‰ to -50‰ δ37Cl, with two spatially and isotopically separated groups of samples averaging -15‰ and -45‰. These extremely low values are the first such detection of any known natural material; common terrestrial values very rarely exceed ±5‰, and the most extreme isotopic signature yet detected elsewhere in the solar system are values of around +24‰ on the Moon. The only other known location in the solar system with large negative chlorine isotopes is the Atacama Desert, where perchlorate with -14‰ δ37Cl has been detected. The Atacama perchlorate has unusual Δ17O signatures associated with it, indicating a formation mechanism involving O3, which suggests an atmospheric origin of the perchlorate and associated large isotopic anomalies. Identification of non-zero positive Δ17O signatures in the O2 released during EGA runs would allow definitive evidence for a similar process having occurred on Mars. Perchlorate is thought to be the most likely source of HCl in EGA runs due to the simultaneous onset of O2 release. If perchlorate is indeed the HCl source, atmospheric chemistry could be responsible for the observed isotopic anomalies, with variable extents of perchlorate production producing the isotopic variability. However, chloride salts have also been observed to release HCl upon heating; if the timing of O2 release is merely coincidental, observed HCl could be coming from chlorides. At thermodynamic equilibrium, the fractionation factor of perchlorate reduction is 0.93, meaning that differing amounts of post-deposition reduction of isotopically normal perchlorate to chloride could account for the highly variable Cl isotopes. Additionally, post-deposition reduction could account for the difference between the two Cl isotopic groups if perchlorate

  20. Stable isotope sales: Mound Facility customer and shipment summaries, FY 1981

    International Nuclear Information System (INIS)

    Ruwe, A.H. Jr.

    1982-01-01

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1981. Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  1. Stable isotope sales; Mound Facility customer and shipment summaries, FY 1977

    International Nuclear Information System (INIS)

    Ruwe, A.H. Jr.

    1978-01-01

    A listing is given of Mound Facility's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for Fiscal Year 1977. Purchasers are listed alphabeticaly and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  2. Photodynamic tissue adhesion with chlorin(e6) protein conjugates.

    Science.gov (United States)

    Khadem, J; Veloso, A A; Tolentino, F; Hasan, T; Hamblin, M R

    1999-12-01

    To test the hypothesis that a photodynamic laser-activated tissue solder would perform better in sealing scleral incisions when the photosensitizer was covalently linked to the protein than when it was noncovalently mixed. Conjugates and mixtures were prepared between the photosensitizer chlorin(e6) and various proteins (albumin, fibrinogen, and gelatin) in different ratios and used to weld penetrating scleral incisions made in human cadaveric eyes. A blue-green (488-514 nm) argon laser activated the adhesive, and the strength of the closure was measured by increasing the intraocular pressure until the wound showed leakage. Both covalent conjugates and noncovalent mixtures showed a light dose-dependent increase in leaking pressure. A preparation of albumin chlorin(e6) conjugate with additional albumin added (2.5 protein to chlorin(e6) molar ratio) showed significantly higher weld strength than other protein conjugates and mixtures. This is the first report of dye-protein conjugates as tissue solders. These conjugates may have applications in ophthalmology.

  3. Chlorination Revisited: Does Cl- Serve as a Catalyst in the Chlorination of Phenols?

    Science.gov (United States)

    Lau, Stephanie S; Abraham, Sonali M; Roberts, A Lynn

    2016-12-20

    The aqueous chlorination of (chloro)phenols is one of the best-studied reactions in the environmental literature. Previous researchers have attributed these reactions to two chlorine species: HOCl (at circum-neutral and high pH) and H 2 OCl + (at low pH). In this study, we seek to examine the roles that two largely overlooked chlorine species, Cl 2 and Cl 2 O, may play in the chlorination of (chloro)phenols. Solution pH, chloride concentration, and chlorine dose were systematically varied in order to assess the importance of different chlorine species as chlorinating agents. Our findings indicate that chlorination rates at pH pH 6.0 and a chlorine dose representative of drinking water treatment, Cl 2 O is predicted to have at best a minor impact on chlorination reactions, whereas Cl 2 may contribute more than 80% to the overall chlorination rate depending on the (chloro)phenol identity and chloride concentration. While it is not possible to preclude H 2 OCl + as a chlorinating agent, we were able to model our low-pH data by considering Cl 2 only. Even traces of chloride can generate sufficient Cl 2 to influence chlorination kinetics, highlighting the role of chloride as a catalyst in chlorination reactions.

  4. 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

    A complex mixture of chlorinated organic compounds is located in an unconfined carbonated bedrock aquifer with low permeability in a former industrial area next to Barcelona (NE Spain). The site exhibited an especially high complexity due to the presence of multiple contaminant sources, wide variety of pollutants (mainly chlorinated ethenes but also chlorinated methanes) and unknown system of fractures (Palau et al., 2014). Interception trenches were installed in the place of the removed pollution sources and were filled with construction wastes with the aim of retaining and treating the accumulated contaminated recharge water before reaching the aquifer. Recycled concrete-based aggregates from a construction and demolition waste recycling plant were used to maintain alkaline conditions in the water accumulated in the trenches (pH 11.6±0.3) and thus induce chloroform (CF) degradation by alkaline hydrolysis. An efficacy of around 30-40% CF degradation in the interception trenches was calculated from the significant and reproducible CF carbon isotopic fractionation (-53±3o obtained in batch experiments (Torrentó et al., 2014). Surprisingly, although hydrolysis of carbon tetrachloride (CT) is extremely slow, a significant CT carbon isotopic enrichment was also observed in the trenches. The laboratory experiments verified the low capability of concrete to hydrolyze the CT and showed the high adsorption of CT on the concrete particles (73% after 50 days) with invariability in its δ13C values. Therefore, the significant CT isotopic fractionation observed in the interception trenches could point out the occurrence of other degradation processes distinct than alkaline hydrolysis. Geochemical speciation modelling using the code PHREEQC showed that water collected at the trenches is supersaturated with respect to several iron oxy-hydroxides and therefore, CT degradation processes related to these iron minerals cannot be discarded. In addition, the combination of alkaline

  5. Thermal diffusion of chlorine in uranium dioxide

    International Nuclear Information System (INIS)

    Pipon, Y.; Toulhoat, N.; Moncoffre, N.; Jaffrezic, H.; Gavarini, S.; Martin, P.; Raimbault, L.; Scheidegger, A.M.

    2006-01-01

    In a nuclear reactor, isotopes such as 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 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 2 . 37 Cl was implanted at a 10 13 at/cm 2 fluence in depleted UO 2 samples which were then annealed in the 900-1200 C temperature range and finally analyzed by secondary ion mass spectrometry (SIMS) to obtain 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 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 2 was examined using micro X-ray fluorescence (micro-XRF) and micro X-ray absorption spectroscopy (micro-XAS). (orig.)

  6. Separation and enrichment of isotopes using laser photochemistry - fundamentals and prospectives

    International Nuclear Information System (INIS)

    Guesten, H.

    1978-01-01

    Basic knowledge is summed up on isotope separation by laser photochemistry. The principal prerequisites are explained of the application of atomic and molecular spectroscopy for this purpose. Practical examples are given of isotope separation of uranium, nitrogen, chlorine, carbon, sulfur, and molybdenum showing the application of two basic techniques, i.e., of gradual atom photoionization or gradual molecule photodissociation and of selective photochemical reactions. (L.K.)

  7. Chlorine in the stratosphere

    OpenAIRE

    VON CLARMANN, T.

    2013-01-01

    This paper reviews the various aspects of chlorine compounds in the stratosphere, both their roles as reactants and as tracers of dynamical processes. In the stratosphere, reactive chlorine is released from chlorofluorocarbons and other chlorine-containing organic source gases. To a large extent reactive chlorine is then sequestered in reservoir species ClONO2 and HCl. Re-activation of chlorine happens predominantly in polar winter vortices by heterogeneous reaction in combination with sunlig...

  8. Direct determination of halogens in powdered geological and environmental samples using isotope dilution laser ablation ICP-MS

    Science.gov (United States)

    Boulyga, Sergei F.; Heumann, Klaus G.

    2005-04-01

    Laser ablation inductively coupled plasma isotope dilution mass spectrometry (LA-ICP-IDMS) with a special laser ablation system for bulk analyses (LINA-Spark(TM)-Atomiser) was applied for direct determinations of chlorine, bromine, and iodine in rock and sediment samples. Special attention was focused on possible inter-halogen fractionations and analyte/spike isotope fractionations by using LA-ICP-MS and LA-ICP-IDMS, respectively. A variation of Br/Cl and I/Cl element intensity ratios by a factor of 1.3-3 was observed when changing the nebulizer gas flow rate in the range of 0.84-1.0 L min-1 and the laser power density in the range of 2-10 GW cm-2, respectively. When using an internal standard for halogen quantification in LA-ICP-MS, this inter-element fractionation can cause systematic errors, which can be avoided by applying the isotope dilution technique. However, at high laser power densities (>5.7 GW cm-2 for iodine and >4.0 GW cm-2 for bromine and chlorine) the corresponding measured isotope ratio of the isotope-diluted sample deviates significantly from the target value. Under optimised conditions concentrations in the range of 30 [mu]g g-1-16 × 103 [mu]g g-1 for chlorine, <2-140 [mu]g g-1 for bromine, and <0.1-31 [mu]g g-1 for iodine were determined by LA-ICP-IDMS in two sediment reference materials (SRM 1646, SRM 2704) and three rock reference samples (GS-N, Granite; BX-N, Bauxite; DT-N, Disthene), which have not been certified for these halogens. The sediment results agree well within the given uncertainties with indicative values by different methods and the results of the rock samples with those obtained by negative thermal ionisation isotope dilution mass spectrometry. The detection limits of LA-ICP-IDMS are 8 [mu]g g-1 for chlorine, 1.7 [mu]g g-1 for bromine, and 0.1 [mu]g g-1 for iodine.

  9. A new chlorine logging tool: Application in the oilfield development with high salinity formation water

    International Nuclear Information System (INIS)

    Qing-Yuan, He; Xin-Miao, Hu; Geng-Fei, Wu; Wen-DA, J.

    1997-01-01

    Radiating formations with isotopes neutron source (Am-Be), and using chlorine element contained in the formation water as a tracer indicator, the chlorine spectrum well logging tool has been regarded as the important and useful tool in the determination of water flooding intensity of formation intervals, especially in the oilfield development stages with high salinity formation water. However, the accuracy of determination of the oil/water-bearings needs to be improved. A new chlorine spectrum logging tool with two detectors has been developed. The short (near) detector uses a He-3 counter tube to measure formation epithermal neutron intensity, the long (far) detector uses a BGO crystal detector to replace traditional Nal detector for measuring the captured X gamma ray spectrum produced by the thermal neutron capture process in the formation. Although the energy resolution of BGO detector to gamma rays is less effective than that of Nal detector, the efficiency of BGO detector to high energy gamma rays is much better. This advantage helps to detect captured chlorine gamma rays, which increases the ability of chlorine element detection. The effect of statistical errors is also reduced. The spectrum autostabilization function in the downhole tool improves the reliability of the whole system. The new chlorine spectrum logging tool can give three log curves simultaneously, these curves are formation porosity, chlorine content, and the ratio of chlorine content and thermal neutron intensity. When formation porosity is larger than 10 p.u, formation water salinity is greater than 40,000 ppm, the resolution to the oil/water-bearings is increased to about 10% compared with the old version tool. Field tests show that the accuracy of water flooding intensity evaluation has been upgraded considerably with the use of new chlorine spectrum logging tool, which contributes greatly to the oilfield development with high salinity formation water

  10. A new chlorine logging tool: Application in the oilfield development with high salinity formation water

    Energy Technology Data Exchange (ETDEWEB)

    Qing-Yuan, He; Xin-Miao, Hu; Geng-Fei, Wu [China National Petroleum Corp. (China). Jianghan Well Logging Institute; Wen-DA, J. [China National Petroleum Corp. (China). Development Bureau

    1997-10-01

    Radiating formations with isotopes neutron source (Am-Be), and using chlorine element contained in the formation water as a tracer indicator, the chlorine spectrum well logging tool has been regarded as the important and useful tool in the determination of water flooding intensity of formation intervals, especially in the oilfield development stages with high salinity formation water. However, the accuracy of determination of the oil/water-bearings needs to be improved. A new chlorine spectrum logging tool with two detectors has been developed. The short (near) detector uses a He-3 counter tube to measure formation epithermal neutron intensity, the long (far) detector uses a BGO crystal detector to replace traditional Nal detector for measuring the captured X gamma ray spectrum produced by the thermal neutron capture process in the formation. Although the energy resolution of BGO detector to gamma rays is less effective than that of Nal detector, the efficiency of BGO detector to high energy gamma rays is much better. This advantage helps to detect captured chlorine gamma rays, which increases the ability of chlorine element detection. The effect of statistical errors is also reduced. The spectrum autostabilization function in the downhole tool improves the reliability of the whole system. The new chlorine spectrum logging tool can give three log curves simultaneously, these curves are formation porosity, chlorine content, and the ratio of chlorine content and thermal neutron intensity. When formation porosity is larger than 10 p.u, formation water salinity is greater than 40,000 ppm, the resolution to the oil/water-bearings is increased to about 10% compared with the old version tool. Field tests show that the accuracy of water flooding intensity evaluation has been upgraded considerably with the use of new chlorine spectrum logging tool, which contributes greatly to the oilfield development with high salinity formation water 4 refs., 2 tabs., 7 figs.

  11. Identification of abiotic and biotic reductive dechlorination in a chlorinated ethene plume after thermal source remediation by means of isotopic and molecular biology tools

    DEFF Research Database (Denmark)

    Badin, Alice; Broholm, Mette Martina; Jacobsen, Carsten S.

    2016-01-01

    Thermal tetrachloroethene (PCE) remediation by steam injection in a sandy aquifer led to the release of dissolved organic carbon (DOC) from aquifer sediments resulting in more reduced redox conditions, accelerated PCE biodegradation, and changes in microbial populations. These changes were...... documented by comparing data collected prior to the remediation event and eight years later. Based on the premise that dual C-Cl isotope slopes reflect ongoing degradation pathways, the slopes associated with PCE and TCE suggest the predominance of biotic reductive dechlorination near the source area. PCE...... is supported by the relative lack of Dhc in the downgradient part of the plume. The results of this study show that thermal remediation can enhance the biodegradation of chlorinated ethenes, and that this effect can be traced to the mobilisation of DOC due to steam injection. This, in turn, results in more...

  12. 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.

  13. Technology assessment: Chlorine chemistry

    International Nuclear Information System (INIS)

    Wolff, H.; Alwast, H.; Buttgereit, R.

    1994-01-01

    Chlorine is not just one of many chemical feedstocks which is used in a few definitely harmful products like PVC or CFC but is irrelevant in all other respects. Just the opposite is true: There is hardly any product line of the chemical industry that can do without chlorine, from herbicides and pesticides to dyes, plastics, pharmaceuticals, photographic atricles, and cosmetics. Chlorine is not only a key element of chemical production but also an ubiquitous element of everyday life in civilisation. There are even many who would agree that the volume of chlorine production is an indicator of the competitive strength and national wealth of a modern society. By now, however, it has become evident that the unreflected use of chlorine is no longer ecologically acceptable. The consequences of a chlorine phase-out as compared to the continued chlorine production at the present level were investigated scientifically by a PROGNOS team. They are presented in this book. (orig.) [de

  14. Chlorination and chloramines formation

    International Nuclear Information System (INIS)

    Yee, Lim Fang; Mohd Pauzi Abdullah; Sadia Ata; Abbas Abdullah; Basar IShak; Khairul Nidzham

    2008-01-01

    Chlorination is the most important method of disinfection in Malaysia which aims at ensuring an acceptable and safe drinking water quality. The dosing of chlorine to surface water containing ammonia and nitrogen compounds may form chloramines in the treated water. During this reaction, inorganic and organic chloramines are formed. The recommended maximum acceptable concentration (MAC) for chloramines in drinking water is 3000 μg/L. The production of monochloramine, dichloramine and trichloramine is highly dependent upon pH, contact time and the chlorine to ammonia molar ratio. The purpose of this study is to examine the formation of chloramines that occur upon the chlorination during the treatment process. Chloramines were determined using the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method. The influences of ammonia, pH and chlorine dosage on the chloramines formation were also studied. This paper presents a modeling approach based on regression analysis which is designed to estimate the formation of chloramines. The correlation between the concentration of chloramines and the ammonia, pH and chlorine dosage was examined. In all cases, the quantity of chloramines formed depended linearly upon the amount of chlorine dosage. On the basis of this study it reveals that the concentration of chloramines is a function of chlorine dosage and the ammonia concentration to the chlorination process. PH seems to not significantly affect the formation of chloramines. (author)

  15. Chlorination of cooling water: a source of chlorine-containing organic compounds with possible environmental significance

    International Nuclear Information System (INIS)

    Jolley, R.L.; Gehrs, C.W.; Pitt, W.W. Jr.

    1976-01-01

    Chlorination of cooling waters may be a source of environmentally significant pollutants. Many water-soluble chlorine-containing organic compounds of low volatility were found in a sample of cooling water chlorinated to a 2-mg/l chlorine concentration in the laboratory. The compounds were separated and detected using a coupled 36 Cl-tracer--high-resolution liquid chromatographic technique developed at the Oak Ridge National Laboratory for determination of chlorinated organics in process effluents. For a chlorination contact time of 75 min at 25 0 C, the yield of chlorine in the form of chloro-organics amounted to 0.78% of the chlorine dosage. It is estimated that the yield is about 0.5% under typical reaction conditions in the electric power plant cooling system chosen for study. Because chlorine is commonly used to remove slime films from the cooling systems of electric power plants, as a means of maintaining high operational efficiency, it is estimated that several hundred tons of chlorinated organics are produced annually in the nation by this antifoulant process. The chromatographic elution positions of some of the separated constituents correspond to those of compounds separated and partially identified from chlorinated sewage treatment plant effluents. The results of this study indicate the formation of chloro-organics during the chlorination of cooling waters should be thoroughly examined, particularly with respect to their identification and determination of possible toxicological properties

  16. Chlorine demand and residual chlorine decay kinetics of Kali river water at Kaiga project area

    International Nuclear Information System (INIS)

    Krishna Bhat, D.; Prakash, T.R.; Thimme Gowda, B.; Sherigara, B.S.; Khader, A.M.A.

    1995-01-01

    The nuclear power plant at Kaiga would use Kali river water for condenser cooling. This necessitated studies on the chemistry of chlorination such as chlorine demand, kinetics of chlorination and other water characteristics aimed at obtaining base line data. The study revealed significant seasonal variation of chlorine demand ranging from 0.5 ppm to 1.7 ppm (3.0 ppm dose, 30 min contact time) and total consumption of 5.0 ppm (10.0 ppm dose, 48 hours contact time). The reaction follows first order kinetics in chlorine. High correlation of chlorine demand with chlorophyll a, suspended matter, turbidity, silica, nitrite, phosphate and sulphate indicated that chlorine demand is greatly influenced by water quality. (author). 3 refs., 1 tab

  17. Fast and Simple Analytical Method for Direct Determination of Total Chlorine Content in Polyglycerol by ICP-MS.

    Science.gov (United States)

    Jakóbik-Kolon, Agata; Milewski, Andrzej; Dydo, Piotr; Witczak, Magdalena; Bok-Badura, Joanna

    2018-02-23

    The fast and simple method for total chlorine determination in polyglycerols using low resolution inductively coupled plasma mass spectrometry (ICP-MS) without the need for additional equipment and time-consuming sample decomposition was evaluated. Linear calibration curve for 35 Cl isotope in the concentration range 20-800 µg/L was observed. Limits of detection and quantification equaled to 15 µg/L and 44 µg/L, respectively. This corresponds to possibility of detection 3 µg/g and determination 9 µg/g of chlorine in polyglycerol using studied conditions (0.5% matrix-polyglycerol samples diluted or dissolved with water to an overall concentration of 0.5%). Matrix effects as well as the effect of chlorine origin have been evaluated. The presence of 0.5% (m/m) of matrix species similar to polyglycerol (polyethylene glycol-PEG) did not influence the chlorine determination for PEGs with average molecular weights (MW) up to 2000 Da. Good precision and accuracy of the chlorine content determination was achieved regardless on its origin (inorganic/organic). High analyte recovery level and low relative standard deviation values were observed for real polyglycerol samples spiked with chloride. Additionally, the Combustion Ion Chromatography System was used as a reference method. The results confirmed high accuracy and precision of the tested method.

  18. Improvements in Precise and Accurate Isotope Ratio Determination via LA-MC-ICP-MS by Application of an Alternative Data Reduction Protocol

    Science.gov (United States)

    Fietzke, J.; Liebetrau, V.; Guenther, D.; Frische, M.; Zumholz, K.; Hansteen, T. H.; Eisenhauer, A.

    2008-12-01

    An alternative approach for the evaluation of isotope ratio data using LA-MC-ICP-MS will be presented. In contrast to previously applied methods it is based on the simultaneous responses of all analyte isotopes of interest and the relevant interferences without performing a conventional background correction. Significant improvements in precision and accuracy can be achieved when applying this new method and will be discussed based on the results of two first methodical applications: a) radiogenic and stable Sr isotopes in carbonates b) stable chlorine isotopes of pyrohydrolytic extracts. In carbonates an external reproducibility of the 87Sr/86Sr ratios of about 19 ppm (RSD) was achieved, an improvement of about a factor of 5. For recent and sub-recent marine carbonates a mean radiogenic strontium isotope ratio 87Sr/86Sr of 0.709170±0.000007 (2SE) was determined, which agrees well with the value of 0.7091741±0.0000024 (2SE) reported for modern sea water [1,2]. Stable chlorine isotope ratios were determined ablating pyrohydrolytic extracts with a reproducibility of about 0.05‰ (RSD). For basaltic reference material JB1a and JB2 chlorine isotope ratios were determined relative to SMOC (standard mean ocean chlorinity) δ37ClJB-1a = (-0.99±0.06) ‰ and δ37ClJB-1a = (-0.60±0.03) ‰ (SD), respectively, in accordance with published data [3]. The described strategies for data reduction are considered to be generally applicable for all isotope ratio measurements using LA-MC-ICP-MS. [1] J.M. McArthur, D. Rio, F. Massari, D. Castradori, T.R. Bailey, M. Thirlwall, S. Houghton, Palaeogeo. Palaeoclim. Palaeoeco., 2006, 242 (126), doi: 10.1016/j.palaeo.2006.06.004 [2] J. Fietzke, V. Liebetrau, D. Guenther, K. Guers, K. Hametner, K. Zumholz, T.H. Hansteen and A. Eisenhauer, J. Anal. At. Spectrom., 2008, 23, 955-961, doi:10.1039/B717706B [3] J. Fietzke, M. Frische, T.H. Hansteen and A. Eisenhauer, J. Anal. At. Spectrom., 2008, 23, 769-772, doi:10.1039/B718597A

  19. Formation of aryl-chlorinated aromatic acids and precursors for chloroform in chlorination of humic acid

    NARCIS (Netherlands)

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

    1985-01-01

    The formation of chloroform when humic substances are chlorinated is well known. Other chlorinated products that may be formed are chloral, di- and trichloroacetic acid, chlorinated C-4 diacids, and α-chlorinated aliphatic acids. Several of these compounds are formed in molar yields comparable

  20. Derivation of a radionuclide inventory for irradiated graphite-chlorine-36 inventory determination

    International Nuclear Information System (INIS)

    Brown, F.J.; Palmer, J.D.; Wood, P.

    2001-01-01

    The irradiation of materials in nuclear reactors results in neutron activation of component elements. Irradiated graphite wastes arise from their use in UK gas-cooled research and commercial reactor cores, and in fuel element components, where the graphite has acted as the neutron moderator. During irradiation the residual chlorine, which was used to purify the graphite during manufacture, is activated to chlorine-36. This isotope is long-lived and poorly retarded by geological barriers, and may therefore be a key radionuclide with respect to post-closure disposal facilities performance. United Kingdom Nirex Limited, currently responsible for the development of a disposal route for intermediate-level radioactive wastes in the UK, carried out a major research programme to support an overall assessment of the chlorine-36 activity of all wastes including graphite reactor components. The various UK gas cooled reactors reactors have used a range of graphite components made from diverse graphite types; this has necessitated a systematic programme to cover the wide range of graphite and production processes. The programme consisted of: precursor measurements - on the surface and/or bulk of representative samples of relevant materials, using specially developed methods; transfer studies - to quantify the potential for transfer of Cl-36 into and between waste streams during irradiation of graphite; theoretical assessments - to support the calculational methodology; actual measurements - to confirm the modelling. For graphite, a total of 458 measurements on samples from 57 batches were performed, to provide a detailed understanding of the composition of nuclear graphite. The work has resulted in the generation of probability density functions (PDF) for the mean chlorine concentration of three classes of graphite: fuel element graphite; Magnox moderator and reflector graphite and AGR reflector graphite; AGR moderator graphite. Transfer studies have shown that a significant

  1. Data for comparison of chlorine dioxide and chlorine disinfection power in a real dairy wastewater effluent

    Directory of Open Access Journals (Sweden)

    Maliheh Akhlaghi

    2018-06-01

    Full Text Available Disinfection of water refers to a special operation that is doing to kill or disable causative organisms (i.e. Pathogens and in particular, intestinal bacteria. The aim of this pilot study is comparison of disinfection power of Chlorine dioxide and chlorine in a real dairy wastewater effluent. In this regard, firstly prepared two 220-l tanks made of polyethylene as reaction tanks and filled by effluent of a dairy wastewater treatment plant. Both tanks were equipped with mechanical stirrer. Then a Diaphragm dosing pumps with the maximum capacity of 3.9 l per hour were used for the chlorine dioxide and chlorine (Calcium hypochlorite 0.5 up to 3 ppm injection. Residual level of Chlorine dioxide and Chlorine were measured by portable photometric method DT4B kit, Germany. Finally, the Multiple-Tube Fermentation, Brilliant Green Bile Broth (BGB and Eosin methylene blue Agar (EMB technique was used for microbial analysis and the results were reported as the most probable number index (MPN respectively. The data showed that the residual of chlorine dioxide could stood more active than residual of chlorine in the aqueous environment significantly. Therefore, Use of chlorine dioxide is more effective than chlorine for removal fecal and total coliform from dairy wastewater effluent. Keywords: Disinfection, Chlorine dioxide, Chlorine, Total coliform, Fecal coliform

  2. Position-specific isotope modeling of organic micropollutants transformations through different reaction pathways

    Science.gov (United States)

    Jin, Biao; Rolle, Massimo

    2016-04-01

    ., 2013. Integrated carbon and chlorine isotope modeling: Applications to chlorinated aliphatic hydrocarbons dechlorination. Environ. Sci. Technol. 47, 1443-1451. doi:10.1021/es304053h. [3] Jin, B., Rolle, M., 2014. Mechanistic approach to multi-element isotope modeling of organic contaminant degradation. Chemosphere 95, 131-139. doi:10.1016/j.chemosphere.2013.08.050.

  3. Transformation mechanism of benzophenone-4 in free chlorine promoted chlorination disinfection.

    Science.gov (United States)

    Xiao, Ming; Wei, Dongbin; Yin, Junxia; Wei, Guohua; Du, Yuguo

    2013-10-15

    The UV-filter BP-4 (2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) has been frequently observed in the environment, showing high potentials to invade drinking water, swimming water, or wastewater reclamation treatment systems. With the help of high performance liquid chromatography-high resolution mass spectrometry and nuclear magnetic resonance spectroscopy, 10 new products from free chlorine-promoted BP-4 disinfection have been disclosed and their possible transformation routes have been investigated. The first route is chlorine substitution of BP-4 and its transformation products, forming mono-, di-, and tri-chlorinated BP-4 analogs. The second is Baeyer-Villiger-Type oxidation, converting diphenyl ketone to phenyl ester derivatives. The third is ester hydrolysis, generating corresponding phenolic and benzoic products. The fourth is decarboxylation, replacing the carboxyl group by chloride in the benzoic-type intermediate. The fifth is desulfonation, degrading the sulfonic group through an alternative chlorine substitution on the benzene ring. Orthogonal experiments have been established to investigate the species transformed from BP-4 at different pH values and free available chlorine (FAC) dosages. The reaction pathways are strongly dependent on pH conditions, while an excessive amount of FAC eliminates BP-4 to the smaller molecules. The initial transformation of BP-4 in chlorination system follows pseudo-first-order kinetics, and its half-lives ranged from 7.48 s to 1.26 × 10(2) s. More importantly, we have observed that the FAC-treated BP-4 aqueous solution might increase the genotoxic potentials due to the generation of chlorinated disinfection by-products. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Study on removing chlorin by conversion-aborption of chlorin resin

    International Nuclear Information System (INIS)

    Huang Yunbai; Zhao Jinfang; Tang Zhijuan; Huang Qijin; Deng Jianguo

    2012-01-01

    Theon version of chlorin resin and the reclamation of acid and uranium in converting solution were investigated. The results indicated the residual chlorin can meet the requirement after converting, acid and uranium in converting solution can be reclaimed. (authors)

  5. Kinetics of molybdenum and chlorine interaction

    International Nuclear Information System (INIS)

    Zelikman, A.N.; Nazarov, Yu.N.; Sarkarov, T.Eh.; Tulyakov, N.V.

    1977-01-01

    The kinetics is studied of molybdenite chlorination with gaseous chlorine. The time dependences of the depth and degree of molybdenite chlorination are given along with the dependence on chlorine concentration of molybdenite chlorination rate. Active interaction is shown to take place at 450-470 deg C. At 350-435 deg C, chlorination occurs in the kinetic range, the apparent activation energy being equal to 22.2 kcal/mole and the order of reaction by chlorine to 0.77. At 435-610 deg C, the process takes place in the diffusion range and is restricted by dissipation of the reaction products (activation energy - 4.05 kcal/mole; order of reaction by chlorine - 0.6)

  6. DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination.

    Science.gov (United States)

    Aghdam, Ehsan; Xiang, Yingying; Sun, Jianliang; Shang, Chii; Yang, Xin; Fang, Jingyun

    2017-08-01

    The formation of disinfection by-products (DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide (DEET) and ibuprofen (IBP) by the ultraviolet irradiation (UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H 2 O 2 process. The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H 2 O 2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species (RCS) and hydroxyl radicals (HO) in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50% after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine (TOCl), respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H 2 O 2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%-63% higher, likely due to the generation of more DBP precursors from the attack of RCS, in addition to HO. Copyright © 2017. Published by Elsevier B.V.

  7. New model of chlorine-wall reaction for simulating chlorine concentration in drinking water distribution systems.

    Science.gov (United States)

    Fisher, Ian; Kastl, George; Sathasivan, Arumugam

    2017-11-15

    Accurate modelling of chlorine concentrations throughout a drinking water system needs sound mathematical descriptions of decay mechanisms in bulk water and at pipe walls. Wall-reaction rates along pipelines in three different systems were calculated from differences between field chlorine profiles and accurately modelled bulk decay. Lined pipes with sufficiently large diameters (>500 mm) and higher chlorine concentrations (>0.5 mg/L) had negligible wall-decay rates, compared with bulk-decay rates. Further downstream, wall-reaction rate consistently increased (peaking around 0.15 mg/dm 2 /h) as chlorine concentration decreased, until mass-transport to the wall was controlling wall reaction. These results contradict wall-reaction models, including those incorporated in the EPANET software, which assume wall decay is of either zero-order (constant decay rate) or first-order (wall-decay rate reduces with chlorine concentration). Instead, results are consistent with facilitation of the wall reaction by biofilm activity, rather than surficial chemical reactions. A new model of wall reaction combines the effect of biofilm activity moderated by chlorine concentration and mass-transport limitation. This wall reaction model, with an accurate bulk chlorine decay model, is essential for sufficiently accurate prediction of chlorine residuals towards the end of distribution systems and therefore control of microbial contamination. Implementing this model in EPANET-MSX (or similar) software enables the accurate chlorine modelling required for improving disinfection strategies in drinking water networks. New insight into the effect of chlorine on biofilm can also assist in controlling biofilm to maintain chlorine residuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Chlorine isn't Just for Swimming Pools Anymore... Chlorination of Organic Compounds in the Arctic

    Science.gov (United States)

    Han, A.; Raab, T. K.

    2013-12-01

    The cycling of chlorine between its organic and inorganic forms is known to occur in forest soils, but little is known about the generality of this mechanism, which soil components chlorine attaches to, and at what rate chlorination occurs. The study uses peat-rich tundra soils from Barrow, Alaska varying in age since formation of 50 yrs - 5500 yrs BP, and seeks to measure the rate at which organic molecules are chlorinated and to understand what changes those molecules undergo once chlorinated. Soil abundance of chlorine and bromine was estimated in soils of varying age using X-ray fluorescence, and org-Cl levels were measured using pyro-hydrolysis [Table 1]. We considered activity of the enzyme Chloroperoxidase, and data was gathered using absorbance scans of the organic molecule monochlorodimedone to determine whether it had been chlorinated and if so, at what rate. Additional information was gathered from the chlorination of small organic components of the macromolecule lignin, whose constituent molecules make up a large portion of humic materials critical to soil health, through emission scans and fluorescence scans. The results showed that the enzyme chloroperoxidase, which is found in nature and is associated with fungi or bacteria, attaches a chlorine atom to monochlorodimedone and that similar enzymes found in Arctic soils act on it, as well as the lignin model subunits cinnamaldehyde ((2E)-3-phenylprop-2-enal) and naringenin-7-rhamnoglucoside. The results may provide more information on chlorination rates in the Arctic and may contribute to an understanding of how and at what rate chlorine changes form in nature, and answer questions about ozone deterioration or anthropogenic chlorine impact(s) on the environment.Average Halogen Abundance in Arctic Soils xrf=Energy Dispersive X-Ray Fluorescencepyro= TOX Pyro-Hydrolysis

  9. 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.

  10. Triple-element compound-specific stable isotope analysis of 1,2-dichloroethane for characterization of the underlying dehalogenation reaction in two Dehalococcoides mccartyi strains.

    Science.gov (United States)

    Franke, Steffi; Lihl, Christina; Renpenning, Julian; Elsner, Martin; Nijenhuis, Ivonne

    2017-12-01

    Chlorinated ethanes belong to the most common groundwater and soil contaminants. Of these, 1,2-dichloroethane (1,2-DCA) is a man-made, persistent and toxic contaminant, released due to improper waste treatment at versatile production sites. This study investigated the anaerobic transformation of 1,2-DCA by Dehalococcoides mccartyi strain 195 and strain BTF08 using triple-element compound-specific stable isotope analysis of carbon, chlorine and hydrogen for the first time. Isotope fractionation patterns for carbon (εCBTF08 = -28.4 ± 3.7‰; εC195 = -30.9 ± 3.6‰) and chlorine (εClBTF08 = -4.6 ± 0.7‰; εCl195 = -4.2 ± 0.5‰) within both investigated D. mccartyi strains, as well as the dual-element analysis (ΛBTF08 = 6.9 ± 1.2; Λ195 = 7.1 ± 0.2), supported identical reaction mechanisms for dehalogenation of 1,2-DCA. Hydrogen isotope fractionation analysis revealed dihaloelimination as prevalent reaction mechanism. Vinyl chloride as major intermediate could be excluded by performing the experiment in deuterated aqueous media. Furthermore, evaluation of the derived apparent kinetic isotope effects (AKIECBTF08 = 1.029/AKIEC195 = 1.031; AKIEClBTF08 = 1.005/AKIECl195 = 1.004) pointed towards simultaneous abstraction of both involved chlorine-substituents in a concerted matter. It was shown that D. mccartyi strain BTF08 and strain 195 are capable of complete, direct dihaloelimination of 1,2-DCA to ethene. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Where does Chlorine-36 go?

    International Nuclear Information System (INIS)

    Anon.

    2000-01-01

    Chlorine-36 and Iodine-129 are the unique long-life radionuclides in the halogen family and halogens are known to be very mobile in the environment. Chlorine-36 is present in slight quantities in radioactive wastes containing carbon or issued from spent fuel reprocessing. The migration of Chlorine-36 in the environment has been very little studied, so a collaboration between the French institute of protection and nuclear safety (IPSN) and the Ukrainian institute for agricultural radioecology (UIAR) has been launched. IPSN will study the migration of Chlorine-36 in soils and UIAR will be in charge of studying the transfer of Chlorine-36 from soil to plants. (A.C.)

  12. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY 1976 and FY 1976A

    International Nuclear Information System (INIS)

    Ruwe, A.H. Jr.

    1977-01-01

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal years 1976 and 1976A (the period July 1, 1975 through September 30, 1976). Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers

  13. 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.

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

    International Nuclear Information System (INIS)

    Garrett, W.E. Jr.; Laylor, M.M.

    1995-01-01

    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

  15. 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.

  16. Water budget of a dam in the semi-arid northeast of Brazil based on oxygen-18 and chlorine contents

    International Nuclear Information System (INIS)

    Stolf, R.; Salati, E.; Menezes Leal, J. de; Fritz, P.

    1979-01-01

    The water balance of an artificial reservoir in the northeast of Brazil is derived by using the variations of oxygen isotopes and chlorine contents. With these two methods, the water losses through subsurface outflow are estimated at 20-40%. A more accurate evaluation would require an investigation of the variability of the relative humidity of the atmosphere. (author)

  17. The study of chlorination of nickel oxide by chlorine and calcium chloride in the presence of active additives

    OpenAIRE

    Ilic, Ilija; Krstev, Boris; Stopic, Srecko; Cerovic, K

    1997-01-01

    Chlorination of nickel oxide by chlorine and calcium chloride in the presence of C, BaS and S were studied, both experimentally and theoretically. Chlorination of nickel oxide by chlorine was carried out in the temperature range 573-873 K and by calcium chloride in the temperature range 1023-1223 K. The results obtained of the chlorination of nickel oxide by chlorine showed that C has the strongest and S the weakest effect on the process. Addition of BaS has a favorable effect on the chlorina...

  18. Separation of chlorinated diastereomers of decarboxy-betacyanins in myeloperoxidase catalyzed chlorinated Beta vulgaris L. extract.

    Science.gov (United States)

    Wybraniec, Sławomir; Starzak, Karolina; Szneler, Edward; Pietrzkowski, Zbigniew

    2016-11-15

    A comparative chromatographic evaluation of chlorinated decarboxylated betanins and betanidins generated under activity of hypochlorous acid exerted upon these highly antioxidative potent decarboxylated pigments derived from natural sources was performed by LC-DAD-ESI-MS/MS. Comparison of the chromatographic profiles of the chlorinated pigments revealed two different directions of retention changes in relation to the corresponding substrates. Chlorination of all betacyanins that are decarboxylated at carbon C-17 results in an increase of their retention times. In contrast, all other pigments (the non-decarboxylated betacyanins as well as 2-decarboxy- and 15-decarboxy-derivatives) exhibit lower retention after chlorination. During further chromatographic experiments based upon chemical transformation of the related pigments (decarboxylation and deglucosylation), the compounds' structures were confirmed. The elaborated method for determination of chlorinated pigments enabled analysis of a chlorinated red beet root extract that was submitted to the MPO/H 2 O 2 /Cl - system acting under inflammation-like conditions (pH 5). This indicates a promising possibility for measurement of these chlorinated pigments as indicators of specific inflammatory states wherein betacyanins and decarboxylated betacyanins act as hypochlorite scavengers. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Stable isotope sales: Mound Laboratory customer and shipment summaries, FY 1976 and FY 1976A

    Energy Technology Data Exchange (ETDEWEB)

    Ruwe, A.H. Jr. (comp.)

    1977-06-06

    A listing is given of Mound Laboratory's sales of stable isotopes of noble gases, carbon, oxygen, nitrogen, chlorine, and sulfur for fiscal years 1976 and 1976A (the period July 1, 1975 through September 30, 1976). Purchasers are listed alphabetically and are divided into domestic and foreign groups. A cross-reference index by location is included for domestic customers. Cross-reference listings by isotope purchased are included for all customers.

  20. Alternative methods for chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Fiessinger, F; Rook, J J; Duguet, J P

    1985-12-01

    Existing disinfectants are oxidative agents which all present negative effects on subsequent treatment processes. None of them has decisive advantages over chlorine, although chlorine-dioxide and chloramines might at times be preferable. Optimum treatment practices will improve the removal of organic precursors before final disinfection which could then consist in a light chlorine addition. A philosophy of radical change in water treatment technology encompassing physical treatment without chemicals such as membrane filtration, solid disinfectants is presented.

  1. OLGA experiments with {sup 261}104 under chlorinating and brominating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gaeggeler, H.W.; Eichler, B.; Jost, D.T.; Piguet, D.; Tuerler, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Buklanov, G.; Lebedev, V.; Timokhin, S.; Vedeev, M.V.; Yakushev, A.; Zvara, I. [FLNR, Dubna (Russian Federation); Huebener, S. [FZR (Germany)

    1997-09-01

    With the On-Line Gas chemistry Apparatus OLGA III the retention times of element 104 chloride and bromide was measured in a quartz column using the isotope {sup 261}104 with a half-life of 78 s. With HCl as chlorinating agent element 104 was found to quantitatively pass through the column at 150{sup o}C, whereas with HBr this temperature shifted to about 300{sup o}C. Under both halogenating conditions, the homologuous element Hf passed through the column at higher temperatures than element 104, in agreement with expectations. (author) 2 figs., 2 refs.

  2. Long term variations of chlorine-36 input signal to groundwater as recorded in deep unsaturated zones, south-east Australia

    International Nuclear Information System (INIS)

    Le Gal La Salle, C.; Herczeg, A.L.; Leaney, F.W.; Fifield, L.K.; Cresswell, R.G.; Kellet, J.

    1997-01-01

    The use of chlorine-36 is increasing in hydrology as its long half-life (3x10 5 a), allows useful long-term investigations into groundwater systems. Because chloride is very hydrophillic, the chlorine-36 signal should not be affected by geochemical processes in most aquatic systems. Nevertheless, over long periods of time, the chlorine-36 input to groundwater systems may vary due to factors such as: changes of production of chlorine-36 and/or changes of its distribution in the atmosphere. For instance the production of chlorine-36 might be governed by long-term terrestrial magnetic dipole strength variations as suggested for other radiogenic isotopes. Variations of the input signal of chlorine-36 should be recorded in pore waters of deep unsaturated zones. In this system, the time scale is approximated by the cumulative chloride content with depth assuming a constant input of chloride. Long-term records of chloride and chlorine-36 in two deep unsaturated-zone profiles, situated in the semi-arid Murray Basin in Australia, are presented. The two profiles record periods of approximately 20±1 to 27±2 ka and 100±5 to 220±10 ka respectively. The range of variation of the recorded time at each site is related to the estimated range of chloride deposition rate. The recharge rates are constant in both profiles with values approximating 0.4 and less than 0.1 mm.a -1 respectively. The linear relationship between chlorine-36 and stable chloride indicates that variations of chlorine-36 are governed by evapotranspiration, with a concentration factor of up to 2. Therefore the chlorine-36 is normalised to chloride to take account of the evapotranspiration process. In the soil profile at Kaniva, Western Victoria, 36 Cl/Cl'- ratio shows an increase of approximately 20% down profile. The second profile at Boree Plains, Wester, NSW, shows variations of 36 Cl/Cl'- ratio of 40% with a decreasing trend down profile. The input signal of chlorine-36/chloride is calculated by correction

  3. Behavior of chlorine in lake water

    International Nuclear Information System (INIS)

    Sriraman, A.K.

    2006-01-01

    Water from monsoon fed Sagre lake is being used as a source of raw water for Tarapur Atomic Power Station (TAPS--1 and 2). The raw water from the lake is initially pumped to Sagre water treatment plant (SWTP) operated by Maharashtra Industrial Development Corporation (MIDC) from where, the processed water is sent to cater the needs of both the units of TAPS-1 and 2, townships of TAPS and MIDC, and the nearby villages. At the SWTP the raw water is treated with alum to remove the turbidity, filtered and chlorinated using bleaching powder. All these years the raw water is chlorinated in such a way whereby a residual chlorine level of 0.5-1.0 mg/l, is maintained at the outlet of water treatment plant. The adequacy of the current chlorination practice was investigated, at the request of the NPC-500 MWe group during 1990, so that the future requirements of raw water for TAPP-3 and 4, can be met from the expanded SWTP. In this connection experiments on chlorine dose -- residual chlorine relationship and the decay pattern of chlorine with time was carried out in the lake water (with low value of total dissolved solids and total hardness 3 sample at the site. The total bacterial count in the raw water observed to be 10 7 counts/ml originally came down to 10 3 counts/ml at the end of one-hour exposure time to chlorine. It was found that the chlorine demand of the water was around 6 mg/l. In addition Jar test to evaluate the aluminum dose was also carried out. Based on these experiments a chlorine dose of 6 mg/l for one hour contact time was arrived at. The experimental findings were in agreement with the current chlorination practices. (author)

  4. Isotopic tracing of perchlorate in the environment

    Science.gov (United States)

    Sturchio, Neil C.; Böhlke, John Karl; Gu, Baohua; Hatzinger, Paul B.; Jackson, W. Andrew; Baskaran, Mark

    2012-01-01

    Isotopic measurements can be used for tracing the sources and behavior of environmental contaminants. Perchlorate (ClO 4 − ) has been detected widely in groundwater, soils, fertilizers, plants, milk, and human urine since 1997, when improved analytical methods for analyzing ClO 4 −concentration became available for routine use. Perchlorate ingestion poses a risk to human health because of its interference with thyroidal hormone production. Consequently, methods for isotopic analysis of ClO 4 − have been developed and applied to assist evaluation of the origin and migration of this common contaminant. Isotopic data are now available for stable isotopes of oxygen and chlorine, as well as 36Cl isotopic abundances, in ClO 4 − samples from a variety of natural and synthetic sources. These isotopic data provide a basis for distinguishing sources of ClO 4 − found in the environment, and for understanding the origin of natural ClO 4 − . In addition, the isotope effects of microbial ClO 4 − reduction have been measured in laboratory and field experiments, providing a tool for assessing ClO 4 − attenuation in the environment. Isotopic data have been used successfully in some areas for identifying major sources of ClO 4 − contamination in drinking water supplies. Questions about the origin and global biogeochemical cycle of natural ClO 4 − remain to be addressed; such work would benefit from the development of methods for preparation and isotopic analysis of ClO 4 − in samples with low concentrations and complex matrices.

  5. Quantifying Short-Chain Chlorinated Paraffin Congener Groups

    NARCIS (Netherlands)

    Yuan, Bo; Bogdal, Christian; Berger, Urs; MacLeod, Matthew; Gebbink, Wouter A.; Alsberg, Tomas; Wit, de Cynthia A.

    2017-01-01

    Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are

  6. Development of a Chlorine Dosing Strategy for Fresh Produce Washing Process to Maintain Microbial Food Safety and Minimize Residual Chlorine.

    Science.gov (United States)

    Chen, Xi; Hung, Yen-Con

    2018-05-22

    The residual free chlorine level in fresh produce wash solution is closely correlated to the chemical and microbial safety of produce. Excess amount of free chlorine can quickly react with organic matters to form hazardous disinfection by-products (DBPs) above EPA-permitted levels, whereas deficiency of residual chlorine in produce wash solution may result in incompletely removing pathogens on produce. The purpose of this study was to develop a chlorine dosing strategy to optimize the chlorine dosage during produce washing process without impacting the microbial safety of fresh produce. Prediction equations were developed to estimate free chlorine needed to reach targeted residual chlorine at various sanitizer pH and organic loads, and then validated using fresh-cut iceberg lettuce and whole strawberries in an automated produce washer. Validation results showed that equations successfully predicted the initial chlorine concentration needed to achieve residual chlorine at 10, 30, 60, and 90 mg/L for both lettuce and strawberry washing processes, with the root mean squared error at 4.45 mg/L. The Escherichia coli O157:H7 reductions only slightly increased on iceberg lettuce and strawberries with residual chlorine increasing from 10 to 90 mg/L, indicating that lowering residual chlorine to 10 mg/L would not compromise the antimicrobial efficacy of chlorine-based sanitizer. Based on the prediction equations and E. coli O157:H7 reduction results, a chlorine dosing strategy was developed to help the produce industry to maintain microbial inactivation efficacy without adding excess amount of free chlorine. The chlorine dosing strategy can be used for fresh produce washing process to enhance the microbial food safety and minimize the DBPs formation potential. © 2018 Institute of Food Technologists®.

  7. Anaerobic biodegradability and toxicity of wastewaters from chlorine and total chlorine-free bleaching of eucalyptus kraft pulps.

    NARCIS (Netherlands)

    Vidal, G.; Soto, M.; Field, J.; Mendez-Pampin, R.; Lema, J.M.

    1997-01-01

    Chlorine bleaching effluents are problematic for anaerobic wastewater treatment due to their high methanogenic toxicity and low biodegradability. Presently, alternative bleaching processes are being introduced, such as elemental chlorine-free (ECF) and total chlorine-free (TCF) bleaching. The

  8. Studies on chlorinated bromide salt for microfouling control

    International Nuclear Information System (INIS)

    Satpathy, K.K.; Rajmohan, R.; Rao, T.S.; Nair, K.V.K.; Mathur, P.K.

    1995-01-01

    The Fast Breeder Test reactor (FBTR) at Kalpakkam has been facing various problems in cooling water systems in spite of intermittent chlorination.Effects of chlorinated-bromide mixture was evaluated against heterotrophic bacteria (TVC) and iron oxidising bacteria (IOB) vis-a-vis chlorine. Results indicated that chlorinated-bromide mixture was far superior (2 orders of magnitude for TVC and 2 times for IOB) to chlorine in microfouling control. Results also showed that at bromide to chlorine ratio of one effectiveness of chlorinated-bromide was at its maximum. (author). 9 refs., 1 tab

  9. 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.

  10. Chlorination of irradiated polyethylene single crystals

    International Nuclear Information System (INIS)

    Grimm, H.J.

    1978-01-01

    The chlorination of electron beam-irradiation polyethylene (PE) single crystals was studied for a range of irradiation doses, temperatures, and chlorine interaction times. The results presented show that PE chlorination was quite extensive, even in unirradiated PE single crystals at 25 0 C in the dark. Electron Spin Resonance (ESR, EPR) was used in this study in order to determine the alkyl radical concentration, decay constant, and diffusivity for (unchlorinated) specimens. An alkyl radical diffusivity D/sub a/ = 1.6 x 10 -17 cm 2 /sec at 25 0 C was estimated from ESR data and alkyl radical migration as one-dimensional unsteady-state diffusion process. In irradiated PE, chlorination occurred mainly via chain reactions which were initiated by the irradiation-produced free radicals. Chlorine content values were determined by X-ray Energy Spectroscopy (XES). It was found that the magnitude of the chlorine uptake increased with increasing dose, and decreased with decreasing temperature at constant dose. Otherwise the observed PE chlorination phenomena was quite similar for all of the doses and temperatures studied here, consisting of a two step mechanism: a fast uptake which occurred between time tCl 2 = 0 - 5 minutes and a slower, approximately first-order rate of uptake which occurred between times tCl 2 = 5 - 120 minutes. Chlorination was essentially complete by time tCl 2 = 120 minutes. The rapid uptake probably occurred in the amorphous surface zones where Cl 2 is relatively high and the second, slower step was probably attributable to Cl 2 diffusion into the crystalline regions and subsequent chlorination there. Inasmuch as the PE density decreases with increasing dose (for 1-600 Mrad), Cl 2 diffusivity was enhanced, resulting in higher chlorine uptake values at higher doses

  11. Formation of assimilable organic carbon during oxidation of natural waters with ozone, chlorine dioxide, chlorine, permanganate, and ferrate.

    Science.gov (United States)

    Ramseier, Maaike K; Peter, Andreas; Traber, Jacqueline; von Gunten, Urs

    2011-02-01

    Five oxidants, ozone, chlorine dioxide, chlorine, permanganate, and ferrate were studied with regard to the formation of assimilable organic carbon (AOC) and oxalate in absence and presence of cyanobacteria in lake water matrices. Ozone and ferrate formed significant amounts of AOC, i.e. more than 100 μg/L AOC were formed with 4.6 mg/L ozone and ferrate in water with 3.8 mg/L dissolved organic carbon. In the same water samples chlorine dioxide, chlorine, and permanganate produced no or only limited AOC. When cyanobacterial cells (Aphanizomenon gracile) were added to the water, an AOC increase was detected with ozone, permanganate, and ferrate, probably due to cell lysis. This was confirmed by the increase of extracellular geosmin, a substance found in the selected cyanobacterial cells. AOC formation by chlorine and chlorine dioxide was not affected by the presence of the cells. The formation of oxalate upon oxidation was found to be a linear function of the oxidant consumption for all five oxidants. The following molar yields were measured in three different water matrices based on oxidant consumed: 2.4-4.4% for ozone, 1.0-2.8% for chlorine dioxide and chlorine, 1.1-1.2% for ferrate, and 11-16% for permanganate. Furthermore, oxalate was formed in similar concentrations as trihalomethanes during chlorination (yield ∼ 1% based on chlorine consumed). Oxalate formation kinetics and stoichiometry did not correspond to the AOC formation. Therefore, oxalate cannot be used as a surrogate for AOC formation during oxidative water treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  12. Characterisation of Chlorine Behavior in French Graphite

    International Nuclear Information System (INIS)

    Blondel, A.; Moncoffre, N.; Toulhoat, N.; Bererd, N.; Petit, L.; Laurent, G.; Lamouroux, C.

    2016-01-01

    Chlorine 36 is one of the main radionuclides of concern for French graphite waste disposal. In order to help the understanding of its leaching behaviour under disposal conditions, the respective impact of temperature, irradiation and gas radiolysis on chlorine release in reactor has been studied. Chlorine 36 has been simulated through chlorine 37 ion implantation in virgin nuclear graphite samples. Results show that part of chlorine is highly mobile in graphite in the range of French reactors operating temperatures in relation with graphite structural recovering. Ballistic damage generated by irradiation also promotes chlorine release whereas no clear impact of the coolant gas radiolysis was observed in the absence of graphite radiolytic corrosion. (author)

  13. δ37Cl of Mid-Ocean Ridge Vent Fluids Determined by a new SIMS Method for Stable Chlorine Isotope Ratio Measurements

    Science.gov (United States)

    Bach, W.; Layne, G. L.; von Damm, K. L.

    2002-12-01

    that phase separation (sub- or super-critical) does not significantly fractionate chlorine isotopes. We suggest, therefore, that the heavy Cl isotope signature of the fluids is a result of seawater-rock interaction and/or mineral precipitation rather than phase separation of seawater. However, the specific mechanisms responsible for this enrichment are not yet understood. The Cl isotope signatures of hydrothermally altered gabbros and sheeted dike rocks (δ37Cl: 0.4-3.4 ‰ ) tend to be heavier than seawater and it has been suggested that this indicates preferential uptake of 37Cl by amphibole (Magenheim et al., EPSL 131, 427-432, 1995). Amphibolitization can therefore not account for the development of the 37Cl enrichment of the fluids. Although the exact mechanisms of Cl isotope fractionation are not yet defined, our data suggest that Cl may not be a strictly conservative component in MOR hydrothermal systems.

  14. Chlorine trifluoride (1963)

    International Nuclear Information System (INIS)

    Vincent, L.M.; Gillardeau, J.

    1963-01-01

    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) [fr

  15. Thermal diffusion and separation of isotopes; Diffusion thermique et separation d'isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Andre

    1944-03-30

    After a review of the various processes used to separate isotopes or at least to obtain mixes with a composition different from the natural proportion, this research addresses the use of thermal diffusion. The author reports a theoretical study of gas thermal diffusion and of the Clusius-Dickel method. In the second part, he reports the enrichment of methane with carbon-13, and of ammoniac with nitrogen-15. The next part reports the experimental study of thermal diffusion of liquids and solutions, and the enrichment of carbon tetra-chloride with chlorine-37. The author then proposes an overview of theories of thermal diffusion in liquid phase (hydrodynamic theory, kinetic theory, theory of caged molecules)

  16. Chlorine solar neutrino experiment

    International Nuclear Information System (INIS)

    Rowley, J.K.; Cleveland, B.T.; Davis, R. Jr.

    1984-01-01

    The chlorine solar neutrino experiment in the Homestake Gold Mine is described and the results obtained with the chlorine detector over the last fourteen years are summarized and discussed. Background processes producing 37 Ar and the question of the constancy of the production rate of 37 Ar are given special emphasis

  17. Transformation of acesulfame in chlorination: Kinetics study, identification of byproducts, and toxicity assessment.

    Science.gov (United States)

    Li, Adela Jing; Wu, Pengran; Law, Japhet Cheuk-Fung; Chow, Chi-Hang; Postigo, Cristina; Guo, Ying; Leung, Kelvin Sze-Yin

    2017-06-15

    Acesulfame (ACE) is one of the most commonly used artificial sweeteners. Because it is not metabolized in the human gut, it reaches the aquatic environment unchanged. In the present study, the reactivity of ACE in free chlorine-containing water was investigated for the first time. The degradation of ACE was found to follow pseudo-first-order kinetics. The first-order rate increased with decreasing pH from 9.4 to 4.8 with estimated half-lives from 693 min to 2 min. Structural elucidation of the detected transformation products (TPs) was performed by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Integration of MS/MS fragments, isotopic pattern and exact mass allowed the characterization of up to 5 different TPs in the ultrapure water extracts analyzed, including two proposed new chlorinated compounds reported for the first time. Unexpectedly, several known and regulated disinfection by-products (DBPs) were present in the ACE chlorinated solution. In addition, two of the six DBPs are proposed as N-DBPs. Time-course profiles of ACE and the identified by-products in tap water and wastewater samples were followed in order to simulate the actual disinfection process. Tap water did not significantly affect degradation, but wastewater did; it reacted with the ACE to produce several brominated-DBPs. A preliminary assessment of chlorinated mixtures by luminescence inhibition of Vibrio fischeri showed that these by-products were up to 1.8-fold more toxic than the parent compound. The generation of these DBPs, both regulated and not, representing enhanced toxicity, make chlorine disinfection a controversial treatment for ACE. Further efforts are urgently needed to both assess the consequences of current water treatment processes on ACE and to develop new processes that will safely treat ACE. Human health and the health of our aquatic ecosystems are at stake. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. 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.)

  19. Cl and C isotope analysis to assess the effectiveness of chlorinated ethene degradation by zero-valent iron: Evidence from dual element and product isotope values

    International Nuclear Information System (INIS)

    Audí-Miró, Carme; Cretnik, Stefan; Otero, Neus; Palau, Jordi; Shouakar-Stash, Orfan; Soler, Albert

    2013-01-01

    Highlights: ► TCE and cis-DCE Cl isotope fractionation was investigated for the first time with ZVI. ► A C–Cl bond is broken in the rate-limiting step during ethylene ZVI dechlorination. ► Dual C/Cl isotope plot is a promising tool to discriminate abiotic degradation. ► Product-related carbon isotopic fractionation gives evidence of abiotic degradation. ► Hydrogenolysis and β-dichloroelimination pathways occur simultaneously. - Abstract: This study investigated C and, for the first time, Cl isotope fractionation of trichloroethene (TCE) and cis-dichloroethene (cis-DCE) during reductive dechlorination by cast zero-valent iron (ZVI). Hydrogenolysis and β-dichloroelimination pathways occurred as parallel reactions, with ethene and ethane deriving from the β-dichloroelimination pathway. Carbon isotope fractionation of TCE and cis-DCE was consistent for different batches of Fe studied. Transformation of TCE and cis-DCE showed Cl isotopic enrichment factors (ε Cl ) of −2.6‰ ± 0.1‰ (TCE) and −6.2‰ ± 0.8‰ (cis-DCE), with Apparent Kinetic Isotope Effects (AKIE Cl ) for Cl of 1.008 ± 0.001 (TCE) and 1.013 ± 0.002 (cis-DCE). This indicates that a C–Cl bond breakage is rate-determining in TCE and cis-DCE transformation by ZVI. Two approaches were investigated to evaluate if isotope fractionation analysis can distinguish the effectiveness of transformation by ZVI as opposed to natural biodegradation. (i) Dual isotope plots. This study reports the first dual (C, Cl) element isotope plots for TCE and cis-DCE degradation by ZVI. The pattern for cis-DCE differs markedly from that reported for biodegradation of the same compound by KB-1, a commercially available Dehalococcoides-containing culture. The different trends suggest an expedient approach to distinguish abiotic and biotic transformation, but this needs to be confirmed in future studies. (ii) Product-related isotope fractionation. Carbon isotope ratios of the hydrogenolysis product cis

  20. Chlorine

    Science.gov (United States)

    ... your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible. Removing and disposing of clothing: Quickly take off clothing that has liquid chlorine on it. Any clothing that has to ...

  1. Toxic effects of chlorinated cake flour in rats.

    Science.gov (United States)

    Cunningham, H M; Lawrence, G A; Tryphonas, L

    1977-05-01

    Four experiments were conducted using weanling Wistar rats to determine whether chlorinated cake flour or its constituents were toxic. Levels of 0.2 and 1.0% chlorine added to unbleached cake flour significantly (p less than 0.01) reduced growth rate by 20.7 and 85.2% and increased liver weight relative to body weight by 16.7 and 25.3%, respectively. Lipids extracted from flour chlorinated at the same levels had similar effects. Rat chow diets containing 0.2 and 0.6% chlorine in the form of chlorinated wheat gluten reduced growth rate and increased liver weight as a percentage of body weight. A rat chow diet containing 0.2% chlorine as chlorinated flour lipids increased absolute liver weight by 40%, kidney by 20%, and heart by 10% compared to pair-fed controls.

  2. 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.

  3. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    Costa, N.G.; Albuquerque Brocchi, E. de

    1990-01-01

    Chlorination experiments were conducted in order to study the kinetics of gasification of the zirconium oxide present in the zirconia concentrate. The variables studied are temperature (1173 to 1373 K), percentage of reducing agent (12 to 36%) and porosity (22 to 30%). The results indicated a greater influence of temperature and percentage of reducing agent as well as allowed the conclusion that a balance between the levels of these variables is an important factor in the appropriate chlorination conditions. (author)

  4. Stratospheric chlorine: Blaming it on nature

    International Nuclear Information System (INIS)

    Taube, G.

    1993-01-01

    Much of the bitter public debate over ozone depletion has centered on the claim that chlorofluorocarbons (CFCs) pale into insignificance alongside natural sources of chlorine in the stratosphere. If so, goes the argument, chlorine could not be depleting ozone as atmospheric scientists claim, because the natural sources have been around since time immemorial, and the ozone layer is still there. The claim, put forward in a book by Rogelio Maduro and Ralf Schauerhammer, has since been touted by former Atomic Energy Commissioner Dixy Lee Ray and talk-show host Rush Limbaugh, and it forms the basis of much of the backlash now being felt by atmospheric scientists. The argument is simple: Maduro and Schauerhammer calculate that 600 million tons of chlorine enters the atmosphere annually from seawater, 36 million tons from volcanoes, 8.4 million tons from biomass burning, and 5 million tons from ocean biota. In contrast, CFCs account for a mere 750,000 tons of atmospheric chlorine a year. Besides disputing the numbers, scientists have both theoretical and observational bases for doubting that much of this chlorine is getting into the stratosphere, where it could affect the ozone layer. Linwood Callis of the National Aeronautics and Space Administration's (NASA) Langley Research Center points out one crucial problem with the argument: Chlorine from natural sources is soluble, and so it gets rained out of the lower atmosphere. CFCs, in contrast, are insoluble and inert and thus make it to the stratosphere to release their chlorine. What's more, observations of stratospheric chemistry don't support the idea that natural sources are contributing much to the chlorine there

  5. Formation of trihalomethanes from the halogenation of 1,3-dihydroxybenzenes in dilute aqueous solution: synthesis of 2-13C-resorcinol and its reaction with chlorine and bromine

    International Nuclear Information System (INIS)

    Boyce, S.D.; Barefoot, A.C.; Britton, D.R.; Hornig, J.F.

    1983-01-01

    As part of this study, the reaction of bromine with resorcinol and structurally related substrates to produce bromoform was examined. Preliminary results suggest that the chlorination and bromination of dihydroxybenzenes proceeded by similar reaction pathways. This chapter describes the successful synthesis of 2- 13 C-1, 3-dihydroxybenzene. Treatment of the isotopically labelled substrate with chlorine and bromine in dilute aqueous solution has elucidated many important details of the sequence of reactions leading to the production of chloroform (CHCl 3 ) and bromoform (CHBr 3 ). The 13 C-enriched products and intermediates formed during these reactions were identified by gas chromatography/mass spectrometry

  6. Recovery of actinides from actinide-aluminium alloys by chlorination: Part III - Chlorination with HCl(g)

    Science.gov (United States)

    Meier, Roland; Souček, Pavel; Walter, Olaf; Malmbeck, Rikard; Rodrigues, Alcide; Glatz, Jean-Paul; Fanghänel, Thomas

    2018-01-01

    Two steps of a pyrochemical route for the recovery of actinides from spent metallic nuclear fuel are being investigated at JRC-Karlsruhe. The first step consists in electrorefining the fuel in molten salt medium implying aluminium cathodes. The second step is a chlorination process for the separation of actinides (An) from An-Al alloys formed on the cathodes. The chlorination process, in turn, consists of three steps; the distillation of adhered salt (1), the chlorination of An-Al by HCl/Cl2 under formation of AlCl3 and An chlorides (2), and the subsequent sublimation of AlCl3 (3). In the present work UAl2, UAl3, NpAl2, and PuAl2 were chlorinated with HCl(g) in a temperature range between 300 and 400 °C forming UCl4, NpCl4 or PuCl3 as the major An containing phases, respectively. Thermodynamic calculations were carried out to support the experimental work. The results showed a high chlorination efficiency for all used starting materials and indicated that the sublimation step may not be necessary when using HCl(g).

  7. Determination of chlorine in nuclear-grade uranium compounds

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan

    1988-01-01

    The determination of chlorine in nuclear-grade uranium compounds is discribed. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800 ∼ 900 deg C. Chlorine is volatilized as hydrochloric acid, absorbed in a dilute alkaline solution and measured with chlorine-selective electrode. This method covers the concentration range of 10 ∼ 500 pm chlorine in uranium oxide. Precision of at least ± 10% and recovery of 85 ∼ 108% have been reported

  8. [Characterization of historical infiltration in the unsaturated zone at the Nevada Test Site using chloride, bromide, and chlorine-36 as environmental tracers]. [Final subcontract report

    International Nuclear Information System (INIS)

    1991-01-01

    This document is an end-of-contract report, prepared by Hydro Geo Chem for Los Alamos National Laboratory under contract number 9-XDD-6329F-1. The ultimate goal of this work is to characterize historical infiltration and unsaturated flow in the Yucca Mountain area of the Nevada Test Site. Work on this contract has focused on using chloride, bromide, stable chlorine isotopes, and chlorine-36 distributions to evaluate the depth of infiltration in the unsaturated zone. Effort in support of this work has included developing analytical procedures, exploring ways in which to separate the. meteoric component from the rock component, and meeting quality assurance requirements

  9. Isotope-abundance variations and atomic weights of selected elements: 2016 (IUPAC Technical Report)

    Science.gov (United States)

    Coplen, Tyler B.; Shrestha, Yesha

    2016-01-01

    There are 63 chemical elements that have two or more isotopes that are used to determine their standard atomic weights. The isotopic abundances and atomic weights of these elements can vary in normal materials due to physical and chemical fractionation processes (not due to radioactive decay). These variations are well known for 12 elements (hydrogen, lithium, boron, carbon, nitrogen, oxygen, magnesium, silicon, sulfur, chlorine, bromine, and thallium), and the standard atomic weight of each of these elements is given by IUPAC as an interval with lower and upper bounds. Graphical plots of selected materials and compounds of each of these elements have been published previously. Herein and at the URL http://dx.doi.org/10.5066/F7GF0RN2, we provide isotopic abundances, isotope-delta values, and atomic weights for each of the upper and lower bounds of these materials and compounds.

  10. Radiation-Initiated Chlorination of 1, 2-Dichloroethane

    Energy Technology Data Exchange (ETDEWEB)

    Danno, A.; Abe, T.; Washino, M.; Souda, T.; Shimada, K. [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, Watanuki-machi, Takasaki-shi, Gunma-ken (Japan)

    1969-12-15

    Radiation-initiated chlorination of 1,2-dichloroethane was carried out with a batch system to study the chlorination reaction in the laboratory and also with a flow system to obtain information on its scale-up. It was found that the direct chlorination of 1,2-dichloroethane in the presence of gamma radiation takes place by a free-radical chain reaction with a high G-value of the order of 10{sup 5}. Successive chlorination of 1,2-dichloroethane gives 1,1, 2-trichloroethane, 1,1,1, 2- and 1,1, 2, 2-tetrachloroethane, pentachloroethane and hexachloroethane. No products other than these polychloro ethanes were detected. The composition of the reaction products depends on the degree of chlorination; it is independent of the dose rate and the chlorine feed rate. A promising application of this process is to produce trichloroethylene and perchloroethylene by thermal dehydrochlorination of a mixture of tetrachloroethane and pentachloroethane. The optimum conditions of producing these compounds with high yields depend on the feed rate of 1, 2-dichloroethane and chlorine gas, the dose rate and the reaction temperature. A pilot experimental facility with a 2-litre reaction vessel has been completed and is now in operation. (author)

  11. Relation between chlorine with the quality of crude water

    International Nuclear Information System (INIS)

    Lim, Fang Yee; Mohd Pauzi Abdullah

    2008-01-01

    Chlorine as disinfection agent in drinking water was used widely since it was successfully been practiced in drinking water in Jersey City, 1908. Mostly, water treatment plants in Malaysia were using chlorine as disinfection agent to kill pathogen and contaminated materials that can be dangerous to consumer. Because of chlorine was a strongly disinfection agent, it also can react with another chemical components such as manganese, hydrogen, sulfides, ammonia and phenol in water. These reactions happen very fast, and chlorine will not react as disinfection agent unless all the organic and inorganic substitution presented in water reacts with chlorine. These reactions between components will increase demand of chlorine in water. The demand of chlorine in water must be filled before the free radical chlorine occurred. These free radical chlorine will decay into hypochlorous acid and hypochlorite ion that so important in disinfection process to kill pathogens and pollutants in water. Most of water treatment plant to maintain free chlorine up to 0.2 mg/ L in distribution system to consumer. These researches involved determination of parameters that can be trusted to react with the chlorine in nine sampling station along Semenyih River and four stations in water treatment plants. These parameters were determined from ammonia, cyanides, sulfides, phenol, phosphorus, nitrite, manganese, iron and sum of organic carbons. Overall, these researches concluded that ammonia and sum of organic carbons were the most compounds that react with the chlorine to produce tryhalometane and chloramines. Besides that, the concentration of cyanides compounds, sulfide, phenol, phosphorus, nitrite, manganese and iron also decrease after the chlorination process. Results can used to evaluate demanding levels of chlorine in Semenyih River. (author)

  12. 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. 2012 American Academy of Forensic Sciences. Published 2012. This article is a U.S. Government work and is in the public domain in the U.S.A.

  13. Bulk chlorine uptake by polyamide active layers of thin-film composite membranes upon exposure to free chlorine-kinetics, mechanisms, and modeling.

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures.

  14. 21 CFR 177.2430 - Polyether resins, chlorinated.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyether resins, chlorinated. 177.2430 Section 177... Components of Articles Intended for Repeated Use § 177.2430 Polyether resins, chlorinated. Chlorinated polyether resins may be safely used as articles or components of articles intended for repeated use in...

  15. Chlorine transportation risk assessment

    International Nuclear Information System (INIS)

    Lautkaski, Risto; Mankamo, Tuomas.

    1977-02-01

    An assessment has been made on the toxication risk of the population due to the bulk rail transportation of liquid chlorine in Finland. Fourteen typical rail accidents were selected and their probability was estimated using the accident file of the Finnish State Railways. The probability of a chlorine leak was assessed for each type of accident separately using four leak size categories. The assessed leakage probability was dominated by station accidents, especially by collisions of a chlorine tanker and a locomotive. Toxication hazard areas were estimated for the leak categories. A simple model was constructed to describe the centring of the densely populated areas along the railway line. A comparison was made between the obtained risk and some other risks including those due to nuclear reactor accidents. (author)

  16. Isothermal gas chromatography of short-lived Hf isotopes and element 104 in chlorinating, oxygen containing carrier gas

    Energy Technology Data Exchange (ETDEWEB)

    Jost, D.T.; Dressler, R.; Eichler, B.; Piguet, D.; Tuerler, A.; Gaeggeler, H.W.; Gaertner, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Grantz, M.; Huebener, S. [FZR (Germany); Buklanov, G.; Lebedev, V.; Timkhin, S.; Vedeneev, M.V.; Yakushev, A.; Zvara, I. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1997-09-01

    Based on thermodynamic state functions retention times of Hf and element 104 were calculated in the case of the simple adsorption of the tetrachlorides and the case of a complex adsorption involving a substitution process with oxygen in the chlorinating gas. Preliminary results for {sup 261}104 and Hf are shown. (author) 1 fig., 1 tab., 3 refs.

  17. Kinetic isotope effects in the OH and Cl reactions of the clumped methane species 13CH3D

    DEFF Research Database (Denmark)

    Joelsson, Magnus

    . As is proven in the current research project, the clumped isotopes are removed by oxidation mechanisms at a slower rate. The residual methane pool is therefore enriched in clumped isotopes compared to the methane from the sources. In order to construct a top-down budget of methane, the clumped kinetic effect...... of the sinkmechanisms must be taken into account. The clumped kinetic effect in atmospheric oxidation of methane has been studied experimentally and theoretically in the three current papers: In Paper I the effect of oxidation by the chlorine radical at roomtemperature (25 ±C) was studied, in Paper II the effect...... of oxidation by the hydroxyl radical over a range of temperatures (5 ±C–40 ±C) was studied, and in Paper III the effect of both the chlorine and the hydroxyl radical at room temperature was studied. All the experiments were conducted in the smog chamber of the Department of Chemistry, University of Copenhagen...

  18. Skeletal and chlorine effects on 13C-NMR chemical shifts of chlorinated polycyclic systems

    Directory of Open Access Journals (Sweden)

    Costa V.E.U.

    1999-01-01

    Full Text Available In order to establish a comparative analysis of chemical shifts caused by ring compression effects or by the presence of a chlorine atom on strained chlorinated carbons, a series of the chlorinated and dechlorinated polycyclic structures derived from "aldrin" (5 and "isodrin" (14 was studied. Compounds were classified in four different groups, according to their conformation and number of ring such as: endo-exo and endo-endo tetracyclics, pentacyclics and hexacyclics. The 13C chemical shift comparison between the chlorinated and dechlorinated compounds showed that when C-9 and C-10 are olefinic carbons, it occurs a shielding of 0.5-2.4 ppm for endo-endo tetracyclics and of 4.7-7.6 ppm for endo-exo tetracyclic. The chemical shift variation for C-11 reaches 49-53 ppm for endo-exo and endo-endo tetracyclics, 54 ppm for pentacyclic and 56-59 ppm for hexacyclic compounds. From these data, it was possible to observe the influence of ring compression on the chemical shifts.

  19. 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 × time reaction ) 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, E a , 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 (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Process for producing chlorinated polyethylene

    International Nuclear Information System (INIS)

    Nose, Shinji; Takayama, Shin-ichi; Kodama, Takashi.

    1970-01-01

    A process for chlorinated polyethylene by the chlorination of an aqueous suspension of polyethylene without the use catalysts is given, using 5-55% by gel content of cross-linked polyethylene powders. The products have favorable material workability, transparency, impact strength and tensile properties. In the case of peroxide cross-linking, a mixture of peroxides with polyethylene must be ground after heat treatment. The polyethylene may preferably have a gel content of 5-55%. The chlorination temperature may be 40 0 C or more, preferably 60 0 to 160 0 C. In one example, high pressure polymerized fine polyethylene powders of 15μ having a density of 0.935 g/cc, a softening point of 114 0 C, an average molecular weight of 35,000 were irradiated in air with 40 Mrad electron beams from a 2 MV Cockcroft-Walton type accelerator at room temperature. The thus irradiated polyethylene had a gel content of 55% and a softening point of 119 0 C. It was chlorinated upto a chlorine content of 33% at 100 0 C. Products were white crystals having a melting point of 122 0 C and a melting heat value of 32 mcal/mg. A sheet formed from this product showed a tensile strength of 280 kg/cm 2 , an elongation of 370% and a hardness of 90. (Iwakiri, K.)

  1. Features of copper etching in chlorine-argon plasma

    International Nuclear Information System (INIS)

    Efremov, A.M.; Svettsov, V.I.

    1995-01-01

    Chlorine mixtures with inert gases including argon exhibit promise as plasma feed gases for etching metals and semiconductors in the microelectronics industry. It was shown that even strong dilution of reactive gas with an inert gas (up to 80-90% of the latter) has virtually no effect in decreasing the rate of plasma etching of materials such as silicon and gallium arsenide, compared to etching in pure chlorine. The principal reactive species responsible for etching these substrates are chlorine atoms therefore, a possible explanation of the effect is an increase in the rate of bulk generation of chlorine atoms in the presence of argon. In this work the authors studied the influence of argon on the rate of copper etching in chlorine, because copper, unlike the above substrates, reacts effectively not only with the atoms but with the ground-state molecules of chlorine

  2. Chlorine poisoning

    Science.gov (United States)

    ... gas) Gas released when opening a partially filled industrial container of chlorine tablets that have been sitting ... change in acid level of the blood (pH balance), which leads to damage in all of the ...

  3. Dispersion of chlorine at seven southern California coastal generating stations

    International Nuclear Information System (INIS)

    Grove, R.S.

    1983-01-01

    The objectives of this study were to (1) determine chlorine concentrations and exposure time gradients of chlorine through seven coastal generating stations and (2) assess the dispersion characteristics of chlorine in the receiving waters. Remarkable variability in chlorine injection concentrations, condenser outlet concentrations, outfall concentrations, and dissipation rates between generating stations and, to a lesser extent, between surveys at the same generating station was found in this chlorine monitoring study. Other than quite consistent low injection and correspondingly low outfall concentrations at San Onofre (a generating station that had one of the more rigorous chlorine control and minimization programs in effect at the time), no recognizable patterns of chlorination could be discerned in the data. Over half of the outfall chlorine surveys had chlorine concentrations below 0.08 mg/L, which is the accepted level of detection for the titrator being used in the surveys. The post-outfall dilution calculations further showed that the chlorine that does enter the receiving water is initially diluted with entrained ambient water at a ratio of 5.2:19.0

  4. Chlorination leaching of cadmium

    International Nuclear Information System (INIS)

    Lach, E.; Pajak, I.; Bojanowska, A.

    1978-01-01

    The results of the investigations on chlorination leaching of cadmium from dust coming from dry dust collector of sinter belt, that is leaching with water saturated with gaseous chlorine and leaching with solutions of ammonium chloride and sodium chloride were given. The optimum conditions for these processes were established. It was found, that the method of leaching in the presence of gaseous chlorine is more effective, as it allows to report into the solution over 90% cadmium contained in dust. Owing to technical difficulties, environmental protection and safety conditions more advantageous seems to be the use as leaching agent of the ammonium chloride solutions. When applying 20% NH 4 Cl and temperature of 60 0 C, the time of 2 hours and the ratio of solid to liquid of 1:5, 70% cadmium contained in the dust can be reported into the solution. (auth.)

  5. Effect of the temperature and the chlorine pressure, over the aluminium chlorides obtained by direct chlorination of the 6061 alloy

    International Nuclear Information System (INIS)

    Alvarez, Fabiola J.; Bohe, Ana E.; Pasquevich, Daniel M.

    2003-01-01

    The aluminium chloride is synthesized by direct chlorination of aluminium, in agreement with the following reaction: Al(s) + 3/2 Cl 2 AlCl 3 (s,g).The present work focuses on the preparation of aluminium chlorides by two methods: (a) Chlorination of 6061 aluminium alloy with gaseous chlorine in sealed containers, filled with different pressures of gas, from 0.8 to 74 Kpa and in the range of temperature between 200 0 and 500 0 C.(b) Chlorination of the same alloy in chlorine flow between 150 0 and 400 0 C.In the sealed systems, the hexahydrated aluminium trichloride predominated over the anhydrous form. For pressures lower than 14 Kpa and temperatures under 250 0 C, the chloride didn't appear.The residues were rich in aluminium, chlorine and magnesium.In the other systems, the anhydrous chloride was found in the areas of the reactor of temperatures above 100 0 C, for all the thermal treatments. The waste was composed by CrCl 3 and AlCl 3 .6H 2 O.The influence of the chlorine pressures and the heating temperature over the characteristics of the product, was studied.The characterization techniques were x-ray diffraction and energy dispersive spectroscopy, and the evolution of the structure was followed by scanning electron microscopy

  6. Radiolytic removal of trihalomethane in chlorinated seawater

    International Nuclear Information System (INIS)

    Rajamohan, R.; Rajesh, Puspalata; Venugopalan, V.P.; Rangarajan, S.; Natesan, Usha

    2015-01-01

    Biofouling is one of the major operational problems in seawater cooling systems. It is controlled by application of chlorine based biocides in the range of 0.5-2.0 mg L -1 . The bromide in seawater reacts with the added chlorine and forms hypobromous acid. The brominated residual biocides react with natural organic matter present in the seawater, resulting in the formation of trihalomethanes (THM) such as bromoform (CHBr 3 ), dibromochloromethane (CHBr 2 Cl) bromodichloromethane (CHBrCl 2 ). Though THMs represent a small fraction of the added chlorine, they are relatively more persistent than residual chlorine, and hence pose a potential hazard to marine life because of their reported mutagenicity. There have been few reports on removal of THMs from chlorinated seawater. In this work, the efficacy of gamma irradiation technique for the removal of THMs from chlorine-dosed seawater was investigated. Experiments were carried out using seawater collected from Kalpakkam. Irradiation study was conducted in chlorinated (1, 3, and 5 mg L -1 of Cl 2 ) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation using a 60 Co Gamma Chamber 5000. Bromoform showed a faster rate of degradation as compared to other halocarbons like bromodichloromethane and dibromochloromethane. This shows the change in total THM concentration with variation in the radiation dose and initial Cl 2 dosing. When the percentage degradation of all the three trihalomethane species was compared with applied doses, it was found that the maximum reduction occurred at a dose of 2.5 kGy. The reduction was almost similar for all the three doses (1, 3, 5 ppm of Cl 2 ) used for chlorination. With a further increase in radiation dose to 5.0 kGy, a slight increase in reduction was observed

  7. Inactivation of viruses in municipal effluent by chlorine.

    OpenAIRE

    Hajenian, H. G.; Butler, M.

    1980-01-01

    The influence of pH and temperature on the efficiency of chlorine inactivation of two unrelated picornaviruses in a typical urban wastewater effluent was examined. Temperature, unlike pH, had relatively little effect on the rate of inactivation. The pH effect was complex and the two viruses differed. The f2 coliphage was more sensitive to chlorine at low pH, but at all values there was a threshold above which additional chlorine resulted in very rapid inactivation. The amount of chlorine requ...

  8. Heat-Activated Persulfate Oxidation of Chlorinated Solvents in Sandy Soil

    Directory of Open Access Journals (Sweden)

    Jialu Liu

    2014-01-01

    Full Text Available Heat-activated persulfate oxidative treatment of chlorinated organic solvents containing chlorinated ethenes and ethanes in soil was investigated with different persulfate dosages (20 g/L, 40 g/L, and 60 g/L and different temperatures (30°C, 40°C, and 50°C. Chlorinated organic solvents removal was increased as persulfate concentration increase. The persulfate dosage of 20 g/L with the highest OE (oxidant efficiency value was economically suitable for chlorinated organic solvents removal. The increasing temperature contributed to the increasing depletion of chlorinated organic solvents. Chlorinated ethenes were more easily removed than chlorinated ethanes. Moreover, the persulfate depletion followed the pseudo-first-order reaction kinetics (kps=0.0292 [PS]0+0.0008, R2=0.9771. Heat-activated persulfate appeared to be an effective oxidant for treatment of chlorinated hydrocarbons.

  9. Chlorination and oxidation of sulfonamides by free chlorine: Identification and behaviour of reaction products by UPLC-MS/MS.

    Science.gov (United States)

    Gaffney, Vanessa de Jesus; Cardoso, Vitor Vale; Benoliel, Maria João; Almeida, Cristina M M

    2016-01-15

    Sulfonamides (SAs) are one class of the most widely used antibiotics around the world and have been frequently detected in municipal wastewater and surface water in recent years. Their transformation in waste water treatment plants (WWTP) and in water treatment plants (WTP), as well as, their fate and transport in the aquatic environment are of concern. The reaction of six sulfonamides (sulfamethoxazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfathiazole and sulfadiazine) with free chlorine was investigated at a laboratory scale in order to identify the main chlorination by-products. A previously validated method, liquid chromatography/mass spectrometry, was used to analyse SAs and their chlorination by-products. At room temperature, pH 6-7, reaction times of up to 2 h and an initial concentration of 2 mg/L of free chlorine, the majority of SAs suffered degradation of around 65%, with the exception of sulfamethoxazole and sulfathiazole (20%). The main reaction of SAs with free chlorine occurred in the first minute. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Study for the chlorination of zirconium oxide

    International Nuclear Information System (INIS)

    Seo, E.S.M.; Takiishi, H.; Paschoal, J.O.A.; Andreoli, M.

    1990-12-01

    In the development of new ceramic and metallic materials the chlorination process constitutes step in the formation of several intermediate compounds, such as metallic chlorides, used for the production of high, purity raw materials. Chlorination studies with the aim of fabrication special zirconium-base alloys have been carried out at IPEN. Within this program the chlorination technique has been used for zirconium tetrachloride production from zirconium oxide. In this paper some relevant parameters such as: time and temperature of reaction, flow rate of chloride gas and percentage of the reducing agent which influence the efficiency of chlorination of zirconium oxide are evaluated. Thermodynamical aspects about the reactions involved in the process are also presented. (author)

  11. 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.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  13. Chlorine diffusion in uranium dioxide under heavy ion irradiation

    International Nuclear Information System (INIS)

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

    2007-01-01

    The radiation enhanced diffusion of chlorine in UO 2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36 Cl, present as an impurity in UO 2 , 37 Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 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 -14 cm 2 s -1 , reflect the high mobility of chlorine in UO 2 during irradiation with fission products

  14. 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.

  15. Automatic analyzing device for chlorine ion

    International Nuclear Information System (INIS)

    Sugibayashi, Shinji; Morikawa, Yoshitake; Fukase, Kazuo; Kashima, Hiromasa.

    1997-01-01

    The present invention provides a device of automatically analyzing a trance amount of chlorine ions contained in feedwater, condensate and reactor water of a BWR type power plant. Namely, zero-adjustment or span calibration in this device is conducted as follows. (1) A standard chlorine ion liquid is supplied from a tank to a mixer by a constant volume pump, and the liquid is diluted and mixed with purified water to form a standard liquid. (2) The pH of the standard liquid is adjusted by a pH adjuster. (3) The standard liquid is supplied to an electrode cell to conduct zero adjustment or span calibration. Chlorine ions in a specimen are measured by the device of the present invention as follows. (1) The specimen is supplied to a head tank through a line filter. (2) The pH of the specimen is adjusted by a pH adjuster. (3) The specimen is supplied to an electrode cell to electrically measure the concentration of the chlorine ions in the specimen. The device of the present invention can automatically analyze trance amount of chlorine ions at a high accuracy, thereby capable of improving the sensitivity, reducing an operator's burden and radiation exposure. (I.S.)

  16. Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Sivakumar, E-mail: srsivakumar@usm.my; Kwok, Teong Chen, E-mail: ctck@live.com; Hamid, Sheikh Abdul Rezan Sheikh Abdul, E-mail: rezanshk@gmail.com [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Penang (Malaysia)

    2016-07-19

    In the present study, chlorination of nitride ilmenite using 2{sup k} factorial design was investigated. The reduction experiments were carried out in a temperature range of 400°C to 500°C, chlorination duration from 1 hour to 3 hours and using different type of carbon reactant. Phases of raw materials and reduced samples were analyzed by X-ray diffraction (XRD). Ilmenite was reduced to TiO{sub x}C{sub y}N{sub z} through carbothermal and nitridation for further chlorination into titanium tetrachloride. The Design of Experiment analysis suggested that the types of carbon reactant contribute most influence to the extent of chlorination of nitride ilmenite. The extent of chlorination was highest at 500°C with 3 hours chlorination time and carbon nanotube as carbon reactant.

  17. Screening of Chlorinated Paraffins and Unsaturated Analogues in Commercial Mixtures: Confirmation of Their Occurrences in the Atmosphere.

    Science.gov (United States)

    Li, Tong; Gao, Shixiong; Ben, Yujie; Zhang, Hong; Kang, Qiyue; Wan, Yi

    2018-02-20

    Characterizing the detailed compositions of chlorinated paraffins (CPs) commercial mixtures is crucial to understand their environmental sources, fates, and potential risks. In this study, dichloromethane (DCM)-enhanced UPLC-ESI-QTOFMS analysis combined with characteristic isotope chlorine peaks is applied to screen all CPs and their structural analogues in the three most commonly produced CP commercial mixtures (CP-42, CP-52, and CP-70). Mass fractions of total short-chain CPs (SCCPs), medium-chain CPs (MCCPs) and long-chain CPs (LCCPs) ranged from 0.64 to 31.9%, 0.64 to 21.8%, and 0.04 to 43.9%, respectively, in the three commercial mixtures. 113 unsaturated SCCPs, MCCPs, and LCCPs were identified in the commercial mixtures. The detailed mass percentages of saturated and unsaturated CPs with carbon numbers of 10-30, chlorine numbers of 5-28, and unsaturated degrees of 0-7 were characterized in all commercial mixtures. Occurrences of the predominant saturated and unsaturated CPs were further confirmed in air samples collected in Guangdong Province, one of the major CP production areas in China, over one year. The profiles of the detected compounds indicated that LCCPs in air samples might come mainly from the production and usage of CP-52, and unsaturated C 24-29 -LCCPs were specifically originated from CP-70 used in the area.

  18. Thermal diffusion and separation of isotopes

    International Nuclear Information System (INIS)

    Fournier, Andre

    1944-01-01

    After a review of the various processes used to separate isotopes or at least to obtain mixes with a composition different from the natural proportion, this research addresses the use of thermal diffusion. The author reports a theoretical study of gas thermal diffusion and of the Clusius-Dickel method. In the second part, he reports the enrichment of methane with carbon-13, and of ammoniac with nitrogen-15. The next part reports the experimental study of thermal diffusion of liquids and solutions, and the enrichment of carbon tetra-chloride with chlorine-37. The author then proposes an overview of theories of thermal diffusion in liquid phase (hydrodynamic theory, kinetic theory, theory of caged molecules)

  19. Effects of Chlorine on Enterovirus RNA Degradation

    Science.gov (United States)

    The primary mechanism of disinfection of waterborne pathogens by chlorine has always been believed to be due to the alteration of proteins by free chlorine and subsequent disruption of their biological structure.

  20. Determination of carbon chlorine and fluorine in uranium dioxide

    International Nuclear Information System (INIS)

    Kijko, N.I.; Timofeev, G.A.

    1983-01-01

    Techniques of chlorine and fluorine determination and simultaneous determination of carbon and chlorine in electrolytic uranium dioxide are described. The method of chlorine and fluorine determination is based on their separation during oxide pyrohydrolysis with subsequent spectrophotometric analysis of condensate. Lower determination limits constitute 1 μg for chlorine, 0.5 μg for fluorine. Relative standard deviation when the content of impurities analyzed is 10 -3 % constitutes 0.05-0.07

  1. Chlorine stable isotope studies of old groundwater, southwestern Great Artesian Basin, Australia

    International Nuclear Information System (INIS)

    Zhang Min; Frape, Shaun K.; Love, Andrew J.; Herczeg, Andrew L.; Lehmann, B.E.; Beyerle, U.; Purtschert, R.

    2007-01-01

    Stable Cl isotope ratios ( 37 Cl/ 35 Cl) were measured in groundwater samples from the southwestern flow system of the Great Artesian Basin, Australia to gain a better understanding of the Cl - sources and transport mechanisms. δ 37 Cl values range from 0 per mille to -2.5 per mille (SMOC), and are inversely correlated with Cl - concentration along the inferred flow direction. The Cl isotopic compositions, in conjunction with other geochemical parameters, suggest that Cl - in groundwaters is not derived from salt dissolution. Mixing of the recharge water with saline groundwater cannot explain the relationship between δ 37 Cl and Cl - concentration measured. Marine aerosols deposited via rainfall and subsequent evapotranspiration appear to be responsible for the Cl - concentrations observed in wells that are close to the recharge area, and in groundwaters sampled along the southern transect. δ 37 Cl values measured in the leachate of the Bulldog shale suggest that the aquitard is the subsurface source of Cl - for the majority of groundwater samples studied. Diffusion is likely the mechanism through which Cl - is transported from the pore water of the Bulldog shale to the aquifer. However, a more detailed study of the aquitard rocks is required to verify this hypothesis

  2. Synthesis and spectral properties of novel chlorinated pH fluorescent probes

    International Nuclear Information System (INIS)

    Wu Xianglong; Jin Xilang; Wang Yunxia; Mei Qibing; Li Jianli; Shi Zhen

    2011-01-01

    Eight chlorinated fluoresceins have been synthesized by the reaction of chlorinated resorcinols with 4, 5, 6, 7-tetrachlorophthalic anhydride or 3, 6-dichloro-4-carboxyphthalic anhydride in the presence of methanesulfonic acid. The spectral properties of the chlorinated fluoresceins were studied. It was found that they have absorption and emission maxima at long wavelengths and high fluorescence quantum yields. Emission spectra of chlorinated fluoresceins shifted towards long wavelength with increase in chlorine. pH-dependent properties of chlorinated fluoresceins were studied in detail. These compounds showed a strongly pH-sensitive range of 3.0-7.0. These chlorinated fluoresceins will be used as pH probes for pH measurement of the cell because of the high quantum yield and strong pH-sensitivity. - Research highlights: → Eight chlorinated fluoresceins have been synthesized in the presence of methanesulfonic acid. → Emission spectra of these compounds shifted towards long wavelength with increase in chlorine. → Eight chlorinated fluoresceins showed a strongly pH-sensitive range of 3.0-7.0. → They have emission maxima at long wavelengths and high fluorescence quantum yields.

  3. 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.

  4. 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....

  5. 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.

  6. Quantifying Short-Chain Chlorinated Paraffin Congener Groups.

    Science.gov (United States)

    Yuan, Bo; Bogdal, Christian; Berger, Urs; MacLeod, Matthew; Gebbink, Wouter A; Alsberg, Tomas; de Wit, Cynthia A

    2017-09-19

    Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a "congener group" C n Cl m . Recently, we resolved individual C n Cl m by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying C n Cl m by introducing C n Cl m specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each C n Cl m are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were -0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q-Orbitrap-MS. C n Cl m concentrations determined with the three instruments were highly correlated (R 2 > 0.90) with each other.

  7. Release of chlorine from biomass at gasification conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerkman, E.; Stroemberg, B. [TPS Termiska Processer AB, Nykoeping (Sweden)

    1997-05-01

    The objective of the project was to investigate the influence of different gasifying atmospheres on the release of chlorine from biomass during gasification conditions. Furthermore, the purpose was also to try and identify the formed chloro compounds. The results showed that O{sub 2}, H{sub 2}O and CO{sub 2} had negligible effect on the chlorine release at temperatures under 700 deg C. At temperatures above 800 deg C the reactivity towards CO{sub 2} increased and could be seen as higher chlorine release and less solid residue. No chloro organic compounds (aliphatic one to six carbons or aromatic one to two rings) could be detected in the tar or the fuel gas produced during pyrolysis/gasifying. On the other hand, comparable amounts of chlorinated benzenes were found in the cooling section during combustion of lucerne and of synthetic waste, indicating that oxygen is essential for chlorination reactions. 11 refs, 4 figs, 1 tab

  8. Release of chlorine from biomass at gasification conditions

    International Nuclear Information System (INIS)

    Bjoerkman, E.; Stroemberg, B.

    1997-05-01

    The objective of the project was to investigate the influence of different gasifying atmospheres on the release of chlorine from biomass during gasification conditions. Furthermore, the purpose was also to try and identify the formed chloro compounds. The results showed that O 2 , H 2 O and CO 2 had negligible effect on the chlorine release at temperatures under 700 deg C. At temperatures above 800 deg C the reactivity towards CO 2 increased and could be seen as higher chlorine release and less solid residue. No chloro organic compounds (aliphatic one to six carbons or aromatic one to two rings) could be detected in the tar or the fuel gas produced during pyrolysis/gasifying. On the other hand, comparable amounts of chlorinated benzenes were found in the cooling section during combustion of lucerne and of synthetic waste, indicating that oxygen is essential for chlorination reactions. 11 refs, 4 figs, 1 tab

  9. Isotopic, hydrochemical, and hydrogeological study of deep aquifer of Sfax: First results

    International Nuclear Information System (INIS)

    Maliki, M. A.; Zouari, K.; Amouri, M.

    1996-01-01

    The water of the chlorinated sodic with chemical facies deep aquifer of Sfax presents a difference on the level of mineralization between the northern sector with a relatively weak salin charge (average of 3,5 g/l) and the southern sector with an important mineralization (about 10g/l). The mineralization of water in linked to dissolution phenomena. Based on the first isotopic results, it seems that the present refill of the deep aquifer of Sfax is very weak (author)

  10. Degradation of acrylamide by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Gao, Ze-Chen; Lin, Yi-Li; Xu, Bin; Pan, Yang; Xia, Sheng-Ji; Gao, Nai-Yun; Zhang, Tian-Yang; Chen, Ming

    2017-11-01

    The degradation of acrylamide (AA) during UV/chlorine advanced oxidation process (AOP) was investigated in this study. The degradation of AA was negligible during UV irradiation alone. However, AA could be effectively degraded and mineralized during UV/chlorination due to the generation of hydroxyl radicals (OH). The degradation kinetics of AA during UV/chlorination fitted the pseudo-first order kinetics with the rate constant between AA and OH radicals being determined as 2.11 × 10 9  M -1  s -1 . The degradation rate and mineralization of AA during UV/chlorination were significantly promoted at acidic conditions as well as increasing chlorine dosage. The volatile degradation products of AA during UV/chlorination were identified using gas chromatography-mass spectrometry and the degradation pathways were then proposed accordingly. The formation of disinfection by-products (DBPs) in Milli-Q water and tap water during UV/chlorination of AA was also investigated. The DBPs included chloroform, dichloroacetonitrile, trichloroacetonitrile, 2,2-dichloroacetamide and 2,2,2-trichloroacetamide. Furthermore, the variations of AA degradation during UV/chlorination in different real water samples were evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Characterization of the bacterial community in shower water before and after chlorination

    KAUST Repository

    Peters, Marjolein C. F. M.

    2017-12-22

    Bathers release bacteria in swimming pool water, but little is known about the fate of these bacteria and potential risks they might cause. Therefore, shower water was characterized and subjected to chlorination to identify the more chlorine-resistant bacteria that might survive in a chlorinated swimming pool and therefore could form a potential health risk. The total community before and after chlorination (1 mg Cl2 L−1 for 30 s) was characterized. More than 99% of the bacteria in the shower water were Gram-negative. The dominant bacterial families with a relative abundance of ≥10% of the total (non-chlorinated and chlorinated) communities were Flavobacteriaceae (24–21%), Xanthomonadaceae (23–24%), Moraxellaceae (12–11%) and Pseudomonadaceae (10–22%). The relative abundance of Pseudomonadaceae increased after chlorination and increased even more with longer contact times at 1 mg Cl2L−1. Therefore, Pseudomonadaceae were suggested to be relatively more chlorine resistant than the other identified bacteria. To determine which bacteria could survive chlorination causing a potential health risk, the relative abundance of the intact cell community was characterized before and after chlorination. The dominant bacterial families in the intact community (non-chlorinated and chlorinated) were Xanthomonadaceae (21–17%) and Moraxellaceae (48–57%). Moraxellaceae were therefore more chlorine resistant than the other identified intact bacteria present.

  12. A study on chlorination of uranium metal using ammonium chloride

    International Nuclear Information System (INIS)

    Eun, H.C.; Kim, T.J.; Jang, J.H.; Kim, G.Y.; Lee, S.J.; Hur, J.M.

    2017-01-01

    In this study, the chlorination of uranium metal using ammonium chloride (NH 4 Cl) was conducted to derive an easy and simple uranium chloride production method without impurities. In thermodynamic equilibrium calculations, it was predicted that only uranium chlorides can be produced by the reactions between uranium metal and NH 4 Cl. Experimental conditions for the chlorination of uranium metal were determined using a chlorination test of cerium metal using NH 4 Cl. It was confirmed that UCl 3 and UCl 4 in the form of particles as uranium chlorination products can be obtained from the chlorination method using NH 4 Cl. (author)

  13. Preliminary GRS Measurement of Chlorine Distribution on Surface of Mars

    Science.gov (United States)

    Keller, J. M.; Boynton, W. V.; Taylor, G. J.; Hamara, D.; Janes, D. M.; Kerry, K.

    2003-12-01

    Ongoing measurements with the Gamma Ray Spectrometer (GRS) aboard Mars Odyssey provide preliminary detection of chlorine at the surface of Mars. Summing all data since boom deployment and using a forward calculation model, we estimate values for chlorine concentration at 5° resolution. Rebinning this data and smoothing with a 15-degree-radius boxcar filter reveal regions of noticeable chlorine enrichment at scales larger than the original 5° resolution and allow for preliminary comparison with previous Mars datasets. Analyzing chlorine concentrations within 30 degrees of the equator, we find a negative correlation with thermal inertia (R2=0.55) and positive correlation with albedo (R2=0.52), indicating that chlorine is associated with fine, non-rock surface materials. Although possibly a smoothing artifact, the spatial correlation is more noticeable in the region covering Tharsis and Amazonis than around Arabia and Elysium. Additionally, a noticeable region of chlorine enrichment appears west of Tharsis Montes ( ˜0 to 20N, ˜110 to 150W) and chlorine concentration is estimated to vary in the equatorial region by over a factor of two. A simplified two-component model involving chlorine-poor rocks and a homogenous chlorine-rich fine material requires rock abundance to vary from zero to over 50%, a result inconsistent with previous measurements and models. In addition to variations in rock composition and distribution, substantial variations in chlorine content of various types of fine materials including dust, sand, and duricrust appear important in explaining this preliminary observation. Surprisingly, visual comparison of surface units mapped by Christensen and Moore (1992) does not show enrichment in chlorine associated with regions of indurated surfaces, where cementation has been proposed. Rather, Tharsis, a region of active deposition with proposed mantling of 0.1 to 2 meters of recent dust (Christensen 1986), shows the greatest chlorine signal. In light of

  14. 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...

  15. Effectiveness of Chlorinated Water, Sodium Hypochlorite, Sodium ...

    African Journals Online (AJOL)

    This study evaluated the efficacy of chlorinated water, sodium hypochlorite solution, sodium chloride solution and sterile distilled water in eliminating pathogenic bacteria on the surfaces of raw vegetables. Lettuce vegetables were dipped in different concentrations of chlorinated water, sodium hypochlorite solution, sodium ...

  16. The Synthesis of Carbon Nanomaterials using Chlorinated ...

    African Journals Online (AJOL)

    The effect of chlorine on the morphology of carbon nanotubes (CNTs) prepared from a Fe-Co/CaCO3 catalyst was investigated using chlorobenzene (CB), dichlorobenzene (DCB), trichlorobenzene (TCB), dichloroethane (DCE), trichloroethane (TCE) and tetrachloroethane (TTCE) as chlorine sources using a catalytic ...

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

    KAUST Repository

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

    2015-01-01

    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.

  18. 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.

  19. Assessing the Impact of Chlorinated-Solvent Sites on Metropolitan Groundwater Resources

    OpenAIRE

    Brusseau, Mark L.; Narter, Matthew

    2013-01-01

    Chlorinated-solvent compounds are among the most common groundwater contaminants in the U.S.A. The majority of the many sites contaminated by chlorinated-solvent compounds are located in metropolitan areas, and most such areas have one or more chlorinated-solvent contaminated sites. Thus, contamination of groundwater by chlorinated-solvent compounds may pose a potential risk to the sustainability of potable water supplies for many metropolitan areas. The impact of chlorinated-solvent sites on...

  20. 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)

  1. Carboranyl-Chlorin e6 as a Potent Antimicrobial Photosensitizer.

    Directory of Open Access Journals (Sweden)

    Elena O Omarova

    Full Text Available Antimicrobial photodynamic inactivation is currently being widely considered as alternative to antibiotic chemotherapy of infective diseases, attracting much attention to design of novel effective photosensitizers. Carboranyl-chlorin-e6 (the conjugate of chlorin e6 with carborane, applied here for the first time for antimicrobial photodynamic inactivation, appeared to be much stronger than chlorin e6 against Gram-positive bacteria, such as Bacillus subtilis, Staphyllococcus aureus and Mycobacterium sp. Confocal fluorescence spectroscopy and membrane leakage experiments indicated that bacteria cell death upon photodynamic treatment with carboranyl-chlorin-e6 is caused by loss of cell membrane integrity. The enhanced photobactericidal activity was attributed to the increased accumulation of the conjugate by bacterial cells, as evaluated both by centrifugation and fluorescence correlation spectroscopy. Gram-negative bacteria were rather resistant to antimicrobial photodynamic inactivation mediated by carboranyl-chlorin-e6. Unlike chlorin e6, the conjugate showed higher (compared to the wild-type strain dark toxicity with Escherichia coli ΔtolC mutant, deficient in TolC-requiring multidrug efflux transporters.

  2. Susceptibility of Legionella pneumophila to chlorine in tap water.

    Science.gov (United States)

    Kuchta, J M; States, S J; McNamara, A M; Wadowsky, R M; Yee, R B

    1983-11-01

    A study was conducted to compare the susceptibility of legionellae and coliforms to disinfection by chlorine. The chlorine residuals used were similar to concentrations that might be found in the distribution systems of large public potable water supplies. The effects of various chlorine concentrations, temperatures, and pH levels were considered. A number of different Legionella strains, both environmental and clinical, were tested. The results indicate that legionellae are much more resistant to chlorine than are coliform bacteria. At 21 degrees C, pH 7.6, and 0.1 mg of free chlorine residual per liter, a 99% kill of L. pneumophila was achieved within 40 min, compared with less than 1 min for Escherichia coli. The observed resistance is enhanced as conditions for disinfection become less optimal. The required contact time for the removal of L. pneumophilia was twice as long at 4 degrees C than it was at 21 degrees C. These data suggest that legionellae can survive low levels of chlorine for relatively long periods of time.

  3. Selective recovery of uranium from Ca-Mg uranates by chlorination

    International Nuclear Information System (INIS)

    Pomiro, Federico J.; Gaviría, Juan P.; Quinteros, Raúl D.

    2017-01-01

    A chlorination process is proposed for the uranium extraction and separation using Calcium−Magnesium uranates such as starting reactants which were obtained by precipitation from uranyl nitrate solutions with calcium hydroxide. The study is based on thermodynamic and reaction analysis using chlorine gas as chlorination agent. The results showed that the chlorination reaction of Ca uranate is more feasible to occur than the Mg uranate. The products obtained after chlorination reactions were washed with deionized water to remove the chlorides produced and analyzed. The XRD patterns of the washed products indicated that the chlorination between 400 and 500 °C result in a single phase of calcium uranate (CaUO 4 ) as reaction product. The formation of U 3 O 8 and MgU 3 O 10 was observed at temperatures between 600 °C and 700 °C for 8 hs. The optimal conditions to recover uranium were 3 l h −1 of chlorine and 10 hs of reaction at 700 °C being U 3 O 8 the single uranium product obtained. - Highlights: •The chlorination is an effective method for the recovery uranium from Ca-Mg uranates. •The optimal conditions were: 10 hs of reaction time at 700 °C using 3 l/h of Cl 2 (g). •U 3 O 8 is recovery by washing out the chlorination by-products.

  4. Selective recovery of uranium from Ca-Mg uranates by chlorination

    Science.gov (United States)

    Pomiro, Federico J.; Gaviría, Juan P.; Quinteros, Raúl D.; Bohé, Ana E.

    2017-07-01

    A chlorination process is proposed for the uranium extraction and separation using Calciumsbnd Magnesium uranates such as starting reactants which were obtained by precipitation from uranyl nitrate solutions with calcium hydroxide. The study is based on thermodynamic and reaction analysis using chlorine gas as chlorination agent. The results showed that the chlorination reaction of Ca uranate is more feasible to occur than the Mg uranate. The products obtained after chlorination reactions were washed with deionized water to remove the chlorides produced and analyzed. The XRD patterns of the washed products indicated that the chlorination between 400 and 500 °C result in a single phase of calcium uranate (CaUO4) as reaction product. The formation of U3O8 and MgU3O10 was observed at temperatures between 600 °C and 700 °C for 8 hs. The optimal conditions to recover uranium were 3 l h-1 of chlorine and 10 hs of reaction at 700 °C being U3O8 the single uranium product obtained.

  5. Detection of chlorinated aromatic compounds

    Science.gov (United States)

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  6. Chlorinated rubbers with advanced properties for tire industry

    Science.gov (United States)

    Mikhaylov, I. A.; Sukhareva, K. V.; Andriasyan, Yu. O.; Popov, A. A.

    2017-12-01

    The paper investigates the production and processing of halide-modified chlorinated rubbers, such as isobutylene isoprene rubber and ethylene-propylene-diene-monomer rubber (IIR and EPDM), which are perspective in terms of application in rubber industry. Prospects for their production and application are determined by the specific properties of these rubbers (low gas permeability of IIR, high heat and ozone resistance of EPDM). These properties are governed by the structure of both initial IIR and EPDM and chlorinated rubbers (ChIIR and ChEPDM). A new alternative technology of obtaining chlorinated elastomers based on solid-phase mechanochemical halide modification is proposed. Novel chlorinated polyolefin rubbers obtained by the developed technology show good technological properties under industrial production conditions due to enhanced covulcanization.

  7. Decomposition of dilute residual active chlorine in sea-water

    International Nuclear Information System (INIS)

    Yoshinaga, Tetsutaro; Kawano, Kentaro; Yanagase, Kenjiro; Shiga, Akira

    1985-01-01

    Coastal industries such as power stations require enormous quantities of sea-water for cooling, but the marine organisms in it often result in fouling and/or blockade of the circulating water condenser and pipeworks. To prevent this, chlorine, or hypochlorite by the direct electrolysis of sea-water have been added. Environmental concerns, however, dictate that the residual chlorine concentration at the outlet should be less than the regulated value (0.02 ppm). Methods for decomposing dilute residual chlorine solutions were therefore studied. It was found that: 1) The addition of (raw) sea-water to the sea-water which passed through the condenser lowered the residual chlorine concentration to an greater extent than could be expected by dilution only. 2) Ozonation of the residual chlorine solution led to degradation of OCl - , but in solutions with a residual chlorine concentrations of less than 3 -- 4 ppm, ozonation had no effect. 3) Irradiation with ultra violet light (254 nm) decomposed the residual chlorine. Under the present work conditions (25 0 C: pH 8; depth 10 mm), nearly first order kinetics were to hold [da/dt = ksub((1)) (1-a)sup(n)]. There is a proportional relationship between the kinetic constant (k) and illuminous intensity (L), i.e., ksub((1))[C 0 sup(Cl 2 ): 10 ppm] = 6.56 x 10 -5 L (L = 0 -- 1000 lx). Thus, the use of both sea-water addition and UV irradiation provides a probable method for decomposing a residual chlorine to the expected concentration. (author)

  8. Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes.

    Science.gov (United States)

    Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Shaodong; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

    2018-06-15

    Degradation of three lipid regulators, i.e., gemfibrozil, bezafibrate and clofibric acid, by a UV/chlorine treatment was systematically investigated. The chlorine oxide radical (ClO • ) played an important role in the degradation of gemfibrozil and bezafibrate with second-order rate constants of 4.2 (±0.3) × 10 8  M -1  s -1 and 3.6 (±0.1) × 10 7  M -1  s -1 , respectively, whereas UV photolysis and the hydroxyl radical (HO • ) mainly contributed to the degradation of clofibric acid. The first-order rate constants (k') for the degradation of gemfibrozil and bezafibrate increased linearly with increasing chlorine dosage, primarily due to the linear increase in the ClO • concentration. The k' values for gemfibrozil, bezafibrate, and clofibric acid degradation decreased with increasing pH from 5.0 to 8.4; however, the contribution of the reactive chlorine species (RCS) increased. Degradation of gemfibrozil and bezafibrate was enhanced in the presence of Br - , whereas it was inhibited in the presence of natural organic matter (NOM). The presence of ammonia at a chlorine: ammonia molar ratio of 1:1 resulted in decreases in the k' values for gemfibrozil and bezafibrate of 69.7% and 7%, respectively, but led to an increase in that for clofibric acid of 61.8%. Degradation of gemfibrozil by ClO • was initiated by hydroxylation and chlorine substitution on the benzene ring. Then, subsequent hydroxylation, bond cleavage and chlorination reactions led to the formation of more stable products. Three chlorinated intermediates were identified during ClO • oxidation process. Formation of the chlorinated disinfection by-products chloral hydrate and 1,1,1-trichloropropanone was enhanced relative to that of other by-products. The acute toxicity of gemfibrozil to Vibrio fischeri increased significantly when subjected to direct UV photolysis, whereas it decreased when oxidized by ClO • . This study is the first to report the transformation pathway of a

  9. Antiradiation effectiveness of the chlorine C

    International Nuclear Information System (INIS)

    Bubnova, O.M.; Grechka, I.I.; Znamensky, V.V.

    1996-01-01

    At present ever more attention of the experimenters in the field of search of high-effective antiray means - is directed to development of preparations from bio-active substances of a natural origin. In this connection all greater interest is caused by researches of antiray activity of these compounds, distinguished, as a rule, from known preparations of synthetic manufacture of low toxicity, absence of expressed collateral effects and possibility of course application. It has biological (antiray) activity in dozes 5-10 mg/kg and chlorine C which is derivative of chlorophil A. At present it passes tests in oncology. Porphyrines (synthetic and natural) are recently subjected to wide study as potential medicinal means, due to their ability to be accumulated in bodies of the reticulo-endothelial system and proliferous tissues, as well as their physical-chemical characteristics (fluorescence, photosensitizing action, colouring). All this testifies for the benefit of perspective use of porphyrin for treatment and diagnostics of tumors. According to the above described properties of porphyrines there is that fact, that for some of them radioprotective properties are revealed during the injections as well as before and after radiation treatment. The above said has formed the basis for study of antiray properties of the chlorine C during the experiments on small-sized laboratory animals. Antiradiation effectivity of chlorine C was studied on the mice (CBA x C57 B1) F1. Chlorine C was applied in a wide range of dozes with its' use in 3 variants: before radiation treatment, after radiation treatment, combined (before and after radiation treatment). Radioprotective activity of chlorine C reduces at an increase of a time of the injection before radiation treatment and at other ways of injection (intramuscularly, subcutaneously, per os). Studies of medical activity of chlorine C in experiments on mice have shown, that the compound does not possess medical activity. The death of

  10. 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...

  11. Bromination vis-a-vis chlorination as a biocide feasibility study

    International Nuclear Information System (INIS)

    Upadhyay, S.K.; Nagaigh, N.; Mittal, S.

    2000-01-01

    Water is used extensively as a cooling medium in various heat transfer equipment's of a power industry such as condenser, heat exchangers and cooling towers. At elevated temperature, the breeding of microbiological growth can form slimes, underneath of this, accelerated corrosion can take place resulting into sudden and catastrophic failure of equipment's. The microbiological growth unchecked in the various systems especially in low velocity areas can lead to large growth of micro organisms such as algae which can even reduce the flow of the fluid thus affecting the efficiency of plant equipment's. Therefore, chlorination is a mandatory requirement in industrial cooling water to reduce biofouling in heat transfer equipment's. The chlorination in drinking water produces germicidal effect and thus reduces the bacterial counts. At NAPS the water quality is good and mild doses of chlorine (5 ppm) two times a day, as envisaged in design is noticed to be satisfactory. The chlorination of recirculating condenser cooling water presently is being done with the established doses for a fixed time twice a day. Some of the problems noticed with the chlorination process are : Corrosion of constructional material of chlorination plant and equipment's and pipelines causing large input of efforts on maintenance for keeping high availability of the chlorination plant. In addition to this, the leakages in the equipment could be a potential safety hazard. The effectiveness of chlorine is observed to be less in alkaline pH (above 9.0) as encountered at NAPS. This results is large quantities of chlorine injection for extended periods. The cost of chlorine and bleaching powder keeps fluctuating in the market as noticed in past few years. Many a times this results in scarcity of chlorine/bleaching powder causing interruption in biofouling control programme. Hence it was felt prudent to work on the alternative biocides which could be cost effective, non-polluting and nature and user

  12. Chloride pyrometallurgy of uranium ore. 1. Chlorination of phosphate ore using solid or gas chlorinating agent and carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1995-01-01

    A thermodynamical and pyrometallurgical study to recover uranium from the phosphate ores was undertaken using the chloride volatilization method. Iron was chlorinated with solid chlorinating agents such as NaCl and CaCl 2 in combination with activated carbon, which will be used for removing this element from the ore, but uranium was not. On the other hand, the chlorination using Cl 2 gas and activated carbon gave a good result at 1,223 K. Not only uranium but also iron, phosphorus, aluminum and silicon were found to form volatile chlorides which vaporized out of the ore, while calcium remained in the ore as non-volatile CaCl 2 . The chlorination condition was studied as functions of temperature, reaction time and carbon content. The volatilization ratio of uranium around 95% was obtained by heating the mixture of the ore and activated carbon (35 wt%) in a mixed gas flow of Cl 2 (200 ml/min) and N 2 (200 ml/min) at 1,223 K for 120 min. (author)

  13. Selective recovery of uranium from Ca-Mg uranates by chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Pomiro, Federico J., E-mail: pomiro@cab.cnea.gov.ar [Departamento de Fisicoquímica y Control de Calidad, Complejo Tecnológico Pilcaniyeu, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Av. Bustillo 9500, 8400 S.C. de Bariloche, Río Negro (Argentina); Gaviría, Juan P. [Departamento de Fisicoquímica y Control de Calidad, Complejo Tecnológico Pilcaniyeu, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Av. Bustillo 9500, 8400 S.C. de Bariloche, Río Negro (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (Argentina); Quinteros, Raúl D. [Departamento de Fisicoquímica y Control de Calidad, Complejo Tecnológico Pilcaniyeu, Centro Atómico Bariloche, Comisión Nacional de Energía Atómica, Av. Bustillo 9500, 8400 S.C. de Bariloche, Río Negro (Argentina); and others

    2017-07-15

    A chlorination process is proposed for the uranium extraction and separation using Calcium−Magnesium uranates such as starting reactants which were obtained by precipitation from uranyl nitrate solutions with calcium hydroxide. The study is based on thermodynamic and reaction analysis using chlorine gas as chlorination agent. The results showed that the chlorination reaction of Ca uranate is more feasible to occur than the Mg uranate. The products obtained after chlorination reactions were washed with deionized water to remove the chlorides produced and analyzed. The XRD patterns of the washed products indicated that the chlorination between 400 and 500 °C result in a single phase of calcium uranate (CaUO{sub 4}) as reaction product. The formation of U{sub 3}O{sub 8} and MgU{sub 3}O{sub 10} was observed at temperatures between 600 °C and 700 °C for 8 hs. The optimal conditions to recover uranium were 3 l h{sup −1} of chlorine and 10 hs of reaction at 700 °C being U{sub 3}O{sub 8} the single uranium product obtained. - Highlights: •The chlorination is an effective method for the recovery uranium from Ca-Mg uranates. •The optimal conditions were: 10 hs of reaction time at 700 °C using 3 l/h of Cl{sub 2}(g). •U{sub 3}O{sub 8} is recovery by washing out the chlorination by-products.

  14. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China); Qiao, Juan, E-mail: qjuan@tsinghua.edu.cn [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Lu, Yun, E-mail: luyun@tsinghua.edu.cn [Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084 (China)

    2016-02-13

    Highlights: • Chlorination is effective to reduce the inflammation inducing capacity of LPS in lung. • LAL-detected endotoxin activity is not correlated to the potency of inflammation induction. • Alkyl chain of LPS was chlorinated in chlorination process. • LPS aggregate size decreases after chlorination. - Abstract: Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies.

  15. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

    International Nuclear Information System (INIS)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani; Qiao, Juan; Lu, Yun

    2016-01-01

    Highlights: • Chlorination is effective to reduce the inflammation inducing capacity of LPS in lung. • LAL-detected endotoxin activity is not correlated to the potency of inflammation induction. • Alkyl chain of LPS was chlorinated in chlorination process. • LPS aggregate size decreases after chlorination. - Abstract: Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies.

  16. The role of chlorine and additives of PVC-plastic in combustion

    International Nuclear Information System (INIS)

    Mattila, H.

    1991-01-01

    The PVC differs from other common plastics due to the chlorine content. As the PVC is combusted, the chlorine is released mainly as hydrogen chloride. The content of chlorinated hydrocarbons is small, but these can also contain polychlorinated dibenzofuranes and dibenzodioxines, which are extremely poisonous. The aim of this study was to find out, what is the portion of PVC combustion in total emission of chlorinated hydrocarbons. Additionally, the amounts chlorine coming into combustion process with ordinary fuels have been estimated, and they are compared with the amounts of PVC. The chloride content of municipal wastes vary in between 0.4-0.9 %. The portion of plastics is about 30 % of the total, and the rest being from paper, food , wood and garden wastes an textiles. Both organic and inorganic chlorine form gaseous hydrogen chlorid in combustion processes. HCl can then react with oxygen and produce caseous chlorine. This can react with unreacted carbon of the smoke and produce different kinds of chlorinated hydrocarbons. The portion of PVC of the chlorine going into combustion in Finland has been estimated to be about 1-2 %. Combustion tests were made using coal and bark and plastic waste as additional fuel. It was noticed that addition of plastic decreased the amount of polyaromatic hydrocarbons in the smoke. Chlorinated dioxins and furans occurred a little less in the gases of combustion of plastic mixtures not containing PVC than in reference tests, but they increased when PVC containing plastic mixture was combusted, but more chlorinated dioxins and furans were absorbed into fly ash, so the emissions remained almost the same

  17. [Toxicity and influencing factors of liquid chlorine on chironomid larvae].

    Science.gov (United States)

    Sun, Xing-Bin; Cui, Fu-Yi; Zhang, Jin-Song; Guo, Zhao-Hai; Xu, Feng; Liu, Li-Jun

    2005-09-01

    The excessive propagation of Chironomid larvae (red worm) in the sedimentation tanks is a difficult problem for the normal function of waterworks. The toxic effect of liquid chlorine on the different instar larvae of Chironomid was studied using distilled water as test sample. Furthermore, the effect of pH value, organic matter content, ammonia nitrogen, and algae content on toxicity of liquid chlorine was observed. The results show that the tolerance of Chironomid larvae to liquid chlorine is strengthened with the increase in instar. The 24h semi-lethal concentration (LC50) of liquid chlorine to the 4th instar larvae of Chironomid is 3.39 mg/L. Low pH value and high algae content are helpful to improve the toxic effect of liquid chlorine to Chironomid larvae. In neutral water body, the increase in organic matter content results in the decrease in the death rate of Chironomid larvae. The toxicity of liquid chlorine differs greatly in different concentrations of ammonia nitrogen. The death rate of the 4th instar larvae of Chironomid in raw water is higher by contrast with that in sedimentation tanks water for 24h disposal with various amount of liquid chlorine.

  18. Radioactive isotope and radiation applications in the German Democratic Republic

    International Nuclear Information System (INIS)

    Leonhardt, J.W.; Wetzel, K.G.

    1988-01-01

    The state of the art of radioisotope and radiation applications in the GDR is reviewed. New results are discussed and the following examples of application are presented: radiometric coal ash monitors, radiotracer optimization of power stations, irradiation of waste cellulose, isotope ratios in natural gas prospection, radiographic imaging of impurities on wafer surfaces, food irradiation, tracer techniques by 15 N, radiation induced chlorination of PVC, radiotracer optimization of a caprolactame plant, ionization detectors for pollutants in the air, X-ray analyzer of pollutants in the wafer, radiation treatment of parquet in the palace of Sanssouci, and characterization of porcelain. 27 refs. (author)

  19. Chlorination of organophosphorus pesticides in natural waters

    Energy Technology Data Exchange (ETDEWEB)

    Acero, Juan L. [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)], E-mail: jlacero@unex.es; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel [Departamento de Ingenieria Quimica y Energetica, Universidad de Extremadura, 06071 Badajoz (Spain)

    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 {sup o}C and pH 7 were determined to be 110.9, 0.004 and 191.6 M{sup -1} s{sup -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{sup -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.

  20. Chlorination of organophosphorus pesticides in natural waters

    International Nuclear Information System (INIS)

    Acero, Juan L.; Benitez, F. Javier; Real, Francisco J.; Gonzalez, Manuel

    2008-01-01

    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 o 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

  1. Regiospecific synthesis of polychlorinated dibenzofurans with chlorine-37 excess

    International Nuclear Information System (INIS)

    Yoonseok Chang; Deinzer, M.L.; Oregon State Univ., Corvallis, OR

    1991-01-01

    The synthesis of regiospecifically chlorine-37 labeled di-and trichlorodibenzofurans is described. The strategy for introducing a chlorine-37 label regiospecifically has been to reduce the nitro derivative to the corresponding amine. The amine is converted to the diazonium salt with t-butyl nitrite, and this product is converted to the final product via the Sandmeyer reaction with chlorine-37 labeled cuprous chloride. (author)

  2. Effect of Chlorine on Giardia lamblia Cyst Viability

    OpenAIRE

    Jarroll, Edward L.; Bingham, Alan K.; Meyer, Ernest A.

    1981-01-01

    The effect of chlorine concentration on Giardia lamblia cyst viability was tested under a variety of conditions. The ability of Giardia cysts to undergo excystation was used as the criterion of viability. The experimental variables employed included temperature (25, 15, and 5°C), pH (6, 7, and 8), chlorine-cyst contact time (10, 30, and 60 min), and chlorine concentration (1 to 8 mg/liter). In the pH range studied, cyst survival generally was observed to increase as buffer pH increased. Water...

  3. Monitoring chlorination practices during operation at TAPS

    International Nuclear Information System (INIS)

    Sriraman, A.K.; Wani, B.N.; Gokhale, A.S.; Yuvaraju, B.

    1995-01-01

    Chlorination of cooling waters is aimed at the condenser surfaces to minimize the biogrowth, while the residual oxidants in the effluents are negligible. This paper describes the fulfillment of the above criteria, as observed during the monitoring of chlorination practices at Tarapur Atomic Power Station (TAPS) during 1990. (author). 4 refs., 2 tabs

  4. Investigation of two technical toxaphene products by using isotope ratio mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, W.; Armbruster, W. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Lebensmittelchemie; Gleixner, G. [Max-Planck-Institut fuer Biogeochemie, Jena (Germany)

    2004-09-15

    Organochlorine compounds have been used in high quantities throughout the past 60 years. Being long-lived in the environment and toxic to humans and wildlife, some of them were classified as persistent organic pollutants (POPs). One of the POPs of special concern is toxaphene which is produced by the chlorination of the natural product camphene (or {alpha}-pinene). The technical products consist of several hundred compounds, mainly of chlorobornanes with an average number of eight chlorine substituents. Toxaphene has been produced in high quantities in different parts of the world. Even though the use has been discontinued during the last two decades, there are still several ecosystems which are heavily contaminated with this chloropesticide. Due to the huge variety of the technical products accompanied with a severe change of composition in the environment, analytical tracing back of toxaphene residues to a specific product has not yet been achieved. One of the potential analytical tools for distinguishing substances that differ only in their way of production is the determination of ratios of stable isotopes ({sup 13}C/{sup 12}C; {sup 2}H/{sup 1}H; {sup 15}N/{sup 14}N). Since the synthesis of toxaphene is starting from natural compounds obtained from different continents, the technical products could have different ratios of stable isotopes. In this study, we investigated the {sup 13}C/{sup 12}C ratio of two former major toxaphene products.

  5. Inactivation Effect of Antibiotic-Resistant Gene Using Chlorine Disinfection

    Directory of Open Access Journals (Sweden)

    Takashi Furukawa

    2017-07-01

    Full Text Available The aim of this study was to elucidate the inactivation effects on the antibiotic-resistance gene (vanA of vancomycin-resistant enterococci (VRE using chlorination, a disinfection method widely used in various water treatment facilities. Suspensions of VRE were prepared by adding VRE to phosphate-buffered saline, or the sterilized secondary effluent of a wastewater treatment plant. The inactivation experiments were carried out at several chlorine concentrations and stirring time. Enterococci concentration and presence of vanA were determined. The enterococci concentration decreased as chlorine concentrations and stirring times increased, with more than 7.0 log reduction occurring under the following conditions: 40 min stirring at 0.5 mg Cl2/L, 20 min stirring at 1.0 mg Cl2/L, and 3 min stirring at 3.0 mg Cl2/L. In the inactivation experiment using VRE suspended in secondary effluent, the culturable enterococci required much higher chlorine concentration and longer treatment time for complete disinfection than the cases of suspension of VRE. However, vanA was detected in all chlorinated suspensions of VRE, even in samples where no enterococcal colonies were present on the medium agar plate. The chlorine disinfection was not able to destroy antibiotic-resistance genes, though it can inactivate and decrease bacterial counts of antibiotic-resistant bacteria (ARB. Therefore, it was suggested that remaining ARB and/or antibiotic-resistance gene in inactivated bacterial cells after chlorine disinfection tank could be discharged into water environments.

  6. Experimental cancer studies of chlorinated by-products

    International Nuclear Information System (INIS)

    Komulainen, Hannu

    2004-01-01

    Chlorinated drinking water contains a number of different by-products formed during the chlorination process from organic matter. The carcinogenicity of only a fraction of them have been evaluated in experimental animals. The focus has been on compounds and groups of compounds that are most abundant in chlorinated drinking water or the in vitro toxicity data have suggested genotoxic potential. From trihalomethanes, chloroform causes liver tumors in mice and female rats and renal tumors in male mice and rats. Tumor formation by chloroform is strongly associated with cytotoxicity and regenerative cell proliferation in tissues and that has been considered to be one determinant of its carcinogenicity. From halogenic acetic acids, dichloroacetic acid (DCA) and trichlotoacetic acid (TCA) are hepatocarcinogenic in mice and DCA in male rats. Their genotoxicity is equivocal and nongenotoxic mechanisms, such as peroxisome proliferation and hypomethylation of DNA in the liver, likely contribute to tumor development. From chlorinated furanones (CHFs), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) is a multisite carcinogen in rats (e.g. in thyroid glands and liver) and it has caused DNA damage in vivo. MX may be a complete carcinogen because it also has promoter properties in vitro. Chlorinated drinking water may also contain brominated by-products providing the raw water contains bromide. At least some of them (bromodichloromethane, bromoform) have been shown to be carcinogenic in laboratory animals. Altogether, although several by-products have been shown to have carcinogenic potential in laboratory animals, it not yet possible to state which compounds or groups of by-products cause the cancer risk in chlorinated drinking water. The cellular mechanisms of their effects and these effects at low concentrations are still poorly understood. The few studies with mixtures of these by-products suggest that the mixture effects may be complex and unpredictable (inhibitory

  7. Study of organic chlorine in soils and formation in biotic and abiotic conditions

    International Nuclear Information System (INIS)

    Osswald, Aurelie

    2016-01-01

    Chlorine has long been considered as the predominantly chlorine form present in the environment. However, recent studies have shown that chlorine is retained in the soil as an organic form and is formed by a natural process of chlorination mainly from the microbial activity of the soil still poorly documented. The aim of this study is to estimate the organic and inorganic forms of chlorine in contrasting soil and highlight the evolution of these forms according to certain environmental parameters or terms of incubations and to the activity of microorganisms. For this, the organo-mineral horizons of contrasting soil were studied (i) in situ: The amounts of chlorine and physico-chemical and microbiological parameters of soil were measured; (ii) in two experimental devices incubations under different conditions. Measurements of chlorine levels between the beginning and the end of the first experiment were measured by AOX analyzer. For the second experiment, the soil was previously enriched with Na 37 Cl and 37 Cl levels were measured by HR ICP MS. Soil samples from these incubations were analyzed by Xanes spectrometry to identify the speciation of chlorine forms in soils. Soil non-extractable organic chlorine contents represent almost all of the chlorine. The parameters that influence the distribution of chlorine contents in soils correspond to vegetation cover, pH, organic carbon content and quantities of microorganisms. The chlorine contents measured by AOX analyzer and by HR ICP MS highlight an organic chlorine formation over time in relation to the microorganisms in the soil. The measures carried out by HR ICP MS show also an organic chlorine formation in abiotic conditions. Conversely, XANES spectrometry measurements have shown any organic chlorine formation. In conclusion, the parameters that influence the distribution of chlorine contents in soils have been targeted. Similarly, the microbial origin of the chlorination process has been demonstrated, although a

  8. 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.

  9. Nonaqueous chlorination of uranium metal in tributyl phosphate

    International Nuclear Information System (INIS)

    Buchikhin, E.P.; Kuznetsov, A.Yu.; Shatalov, V.V.; Vidanov, V.L.; Chekmarev, A.M.

    2005-01-01

    Low-temperature (30-50 deg C) chlorination of uranium metal in the TBP-TCE-Cl 2 system (TCE = tetrachloroethylene) was studied. Dissolution of uranium in the dipolar aprotic solvent proceeds with formation of U(IV) compounds. The activation energy of this process is 31.24 kJ mol -1 , and relative reaction order with respect to Cl 2 is 2. The effect of TBP concentration on chlorination was examined. The chlorination rate sharply increases at a water content in the TBP-TCE system of 0.2- 0.6 vol % [ru

  10. 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)

    1994-12-31

    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.

  11. 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.

  12. Study of the production of zirconium tetrachloride by chlorination of its oxide

    International Nuclear Information System (INIS)

    Seo, E.S.M.

    1983-01-01

    The studies carried out on the production of zirconium tetrachloride by chlorination of pure zirconium oxide with carbon tetrachloride and chlorine in the presence of carbon. In the process of chlorination with carbon tetrachloride, the chlorination efficiency increases with the rise in temperature at intervals between 450 and 750 0 C. The flow of the carbon tetrachloride vapour was 1.50l/min. Higher temperatures of 700 to 850 0 C were used for the zirconium oxide chlorination in the presence of carbon, and the flowrate of the chlorine gas used in the process was 0.50 l/min. Pure zirconium oxide chlorination as well as zirconium oxide - carbon misture chlorination have been studied in connection with the time of reaction at different temperatures and the apparent rate constant, the activation energies, the order of reaction in relation to the concentration of the gases (CCl 4 and Cl 2 ) and the content of carbon in the pellet have all been determined. (Author) [pt

  13. Chlorination for biofouling control in power plant cooling water system - a review

    International Nuclear Information System (INIS)

    Satpathy, K.K.; Ruth Nithila, S.D.

    2008-01-01

    Fresh water is becoming a rare commodity day by day and thus power plant authorities are turning into sea to make use of the copious amount of seawater available at an economical rate for condenser cooling. Unfortunately, biofouling; the growth and colonization of marine organisms affect the smooth operation of power plant cooling water systems. This is more so, if the plant is located in tropical climate having clean environment, which enhances the variety and density of organisms. Thus, biofouling needs to be controlled for efficient operation of the power plant. Biocide used for biofouling control is decided based on three major criteria viz: it should be economically, operationally and environmentally acceptable to the power plant authorities. Chlorine among others stands out on the top and meets all the above requirements in spite of a few shortcomings. Therefore it is no wonder that still chlorine rules the roost and chlorination remains the most common method of biofouling control in power plant cooling water system all over the world. Although, it is easier said than done, a good amount of R and D work is essential before a precise chlorination regime is put into pragmatic use. This paper discusses in details the chemistry of chlorination such as chlorine demand, chlorine decay, break point chlorination, speciation of chlorine residual and role of temperature and ammonia on chlorination in biofouling control. Moreover, targeted and pulse chlorination are also discussed briefly. (author)

  14. Effects of aging on chlorinated plasma polymers

    Energy Technology Data Exchange (ETDEWEB)

    Turri, Rafael Gustavo; Amorim, Milena Kowalczuk Manosso; Hadich, Tayan Vieira; Fernandes, Isabela Cristina; Fernandes, Gabriel Ferreira; Rossi, Diego; Rangel, Elidiane Cipriano; Durrant, Steven Frederick, E-mail: steve@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos

    2017-07-15

    Thin films deposited from propanol-chloroform-argon mixtures by plasma enhanced chemical vapor deposition at different partial pressures of chloroform in the feed, C{sub Cl}, were characterized after two years of aging and their characteristics compared with their as-deposited properties. Film thickness decreased and surface roughness increased with aging. Surface contact angles also increased with aging for the chlorinated films. For the film deposited with 40% chloroform in the feed the contact angle increased about 14°. Transmission infrared and Energy dispersive X-ray spectroscopy revealed that the films gain carbonyl and hydroxyl groups and lose chlorine and hydrogen on aging. Chlorination appears to make the films more durable. Delamination was observed for the unchlorinated films. (author)

  15. Blends of caprolactam/caprolactone copolymers and chlorinated polymers

    NARCIS (Netherlands)

    Alberda van Ekenstein, G.O.R.; Deuring, H.; ten Brinke, G.; Ellis, T.S.

    The phase behaviour of blends of chlorinated polyethylene, polyvinyl chloride (PVC) and chlorinated PVC with random copolymers of caprolactone and caprolactam has been investigated and the results correlated with a binary interaction model. The known miscibility of polycaprolactone in the

  16. Chlorinated cooling waters in the marine environment: development of effluent guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Capuzzo, J M; Goldman, J C; Davidson, J A; Lawrence, S A

    1977-07-01

    The effects of free chlorine and chloramine on stage I lobster larvae and juvenile killifish were investigated in continuous flow bioassay units. In comparing mortality and changes in standard respiration rates during and after exposure to either chlorine form, significant respiratory stress was observed with exposure to sublethal levels. Sublethal responses to free and combined chlorine should be considered when establishing regulations for chlorine residuals in cooling waters.

  17. 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

    Chlorine is very soluble at a global scale with chloride (Cl-), the dominating form. Because of its high mobility, chlorine is usually perceived as a good conservative tracer in hydrological studies and by analogy as little reactive in biosphere. Since 36Cl can be considered to have the same behaviour than stable Cl, a good knowledge of chlorine distribution between compartments of terrestrial ecosystems is sufficient to calibrate a specific activity model which supposes rapid dilution of 36Cl within the large pool of stable Cl and isotopic equilibrium between compartments. By assuming 36Cl redistribution similar to that of stable Cl at steady-state, specific activity models are simplified interesting tools for regulatory purposes in environmental safety assessment, especially in case of potential long term chronic contamination of agricultural food chain (IAEA, 2010). In many other more complex scenarios (accidental acute release, intermediate time frame, and contrasted natural ecosystems), new information and tools are necessary for improving (radio-)ecological realism, which entails a non-conservative behavior of chlorine. Indeed observed dynamics of chlorine in terrestrial ecosystems is far from a simple equilibrium notably because of natural processes of organic matter (SOM) chlorination mainly occurring in surface soils (Öberg, 1998) and mediated by microbial activities on a large extent (Bastviken et al. 2007). Our recent studies have strengthened the view that an organic cycle for chlorine should now be recognized, in addition to its inorganic cycle. Major results showed that: organochlorine (Clorg) formation occurs in all type of soils and ecosystems (culture, pasture, forest), leading to an average fraction of the total Cl pool in soil of about 80 % (Redon et al., 2012), chlorination in more organic soils over time leads to a larger Clorg pool and in turn to a possible high internal supply of inorganic chlorine (Clin) upon dechlorination. (Gustafsson et

  18. Direct Chlorination of Zircon Sand

    International Nuclear Information System (INIS)

    Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

    2002-01-01

    It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

  19. 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.

  20. Determination of chlorine in nuclear-grade uranium compounds by ion-selective electrode

    International Nuclear Information System (INIS)

    Yang Chunqing; Liu Fuyun; Huang Dianfan.

    1989-01-01

    The determination of microamount chlorine in nuclear-grade uranium compounds is described. Chlorine is separated from uranium oxide pyrohydrolytically with stream of wet oxygen in a furnace at 800-900 deg C. Chlorine is volatilized as hydrochloric acid, which then is absorbed in a dilute alkaline solution and measured with chlorine selective electrode. This method covers the concentration range of 10-500 ppm chlorine in uranium oxide. The relative standard diviation is better than 10% and recovery of 85-108% has been reported

  1. Dense chlorinated solvents and other DNAPLs in groundwater

    DEFF Research Database (Denmark)

    Broholm, K.

    1996-01-01

    Anmeldelse af Pankow,J.F. & Cherry,J.A.: Dense chlorinated solvents and other DNAPLs in groundwater. Waterloo Press, Portland, Oregon, USA, 1996......Anmeldelse af Pankow,J.F. & Cherry,J.A.: Dense chlorinated solvents and other DNAPLs in groundwater. Waterloo Press, Portland, Oregon, USA, 1996...

  2. Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers.

    Science.gov (United States)

    Huang, Hai; Lin, Saisai; Zhang, Lin; Hou, Li'an

    2017-03-22

    Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

  3. 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

  4. Determination of Residual Chlorine and Turbidity in Drinking Water. Instructor's Manual.

    Science.gov (United States)

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This instructor's guide presents analytical methods for residual chlorine and turbidity. Topics include sample handling, permissable concentration levels, substitution of residual chlorine for bacteriological work, public notification, and the required analytical techniques to determine residual chlorine and turbidity. This publication is intended…

  5. Determination of Residual Chlorine and Turbidity in Drinking Water. Student Manual.

    Science.gov (United States)

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This student's manual covers analytical methods for residual chlorine and turbidity. Topics include sample handling, permissable concentration levels, substitution of residual chlorine for bacteriological work, public notification, and the required analytical techniques to determine residual chlorine and turbidity. The publication is intended for…

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

    International Nuclear Information System (INIS)

    Fontcuberta, M.; Arques, J.F.; Villalbi, J.R.; Martinez, M.; Centrich, F.; Serrahima, E.; Pineda, L.; Duran, J.; Casas, C.

    2008-01-01

    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 α, β 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

  7. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    International Nuclear Information System (INIS)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P.; Cassayre, L.

    2008-01-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl 3 . A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl 3 is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl 5 and UCl 6 . It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  8. Bacterial repopulation of drinking water pipe walls after chlorination.

    Science.gov (United States)

    Mathieu, Laurence; Francius, Grégory; El Zein, Racha; Angel, Edith; Block, Jean-Claude

    2016-09-01

    The short-term kinetics of bacterial repopulation were evaluated after chlorination of high-density polyethylene (HDPE) colonized with drinking water biofilms and compared with bare HDPE surfaces. The effect of chlorination was partial as a residual biofilm persisted and was time-limited as repopulation occurred immediately after water resupply. The total number of bacteria reached the same levels on both the bare and chlorinated biofilm-fouled HDPE after a seven-day exposure to drinking water. Due to the presence of a residual biofilm, the hydrophobicity of chlorinated biofilm-fouled surface exhibited much lower adhesion forces (2.1 nN) compared to bare surfaces (8.9 nN). This could explain the rapid repopulation after chlorination, with a twofold faster bacterial accumulation rate on the bare HDPE surface. γ-Proteobacteria dominated the early stages of repopulation of both surfaces and a shift in the dominance occurred over the colonization time. Such observations define a timescale for cleaning frequency in industrial environments and guidelines for a rinsing procedure using drinking water.

  9. Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E.; Malmbeck, R.; Soucek, P.; Jardin, R.; Glatz, J.P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany); Cassayre, L. [Laboratoire de Genie Chimique (LGC), Universite Paul Sabatier, UMR CNRS 5503, 118 route de Narbonne, 31062 Toulouse Cedex 04 (France)

    2008-07-01

    A method for recovery of actinides (An) from An-Al alloys formed by electrochemical separation of metallic spent nuclear fuel on solid aluminium electrodes in molten chloride salts is described. The proposed route consists of three main steps: -) vacuum distillation of salt adhered on the electrodes, -) chlorination of An-Al alloy by pure chlorine gas and -) sublimation of formed AlCl{sub 3}. A thermochemical study of the route was performed to determine important chemical reactions and to find optimum experimental conditions for all process steps. Vacuum distillation of the electrode is efficient for complete removal of remaining salt and most fission products, full chlorination of the An-Al alloys is possible at any working temperature and evaporation of AlCl{sub 3} is achieved by heating under argon. Experiments have been carried out using U-Al alloy in order to define parameters providing full alloy chlorination without formation of volatile UCl{sub 5} and UCl{sub 6}. It was shown that full chlorination of An-Al alloys without An losses should be possible at a temperature approx. 150 deg. C. (authors)

  10. CHLORINE ABUNDANCES IN COOL STARS

    Energy Technology Data Exchange (ETDEWEB)

    Maas, Z. G.; Pilachowski, C. A. [Indiana University Bloomington, Astronomy Department, Swain West 319, 727 East Third Street, Bloomington, IN 47405-7105 (United States); Hinkle, K., E-mail: zmaas@indiana.edu, E-mail: cpilacho@indiana.edu, E-mail: hinkle@noao.edu [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States)

    2016-12-01

    Chlorine abundances are reported in 15 evolved giants and 1 M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H{sup 35}Cl at 3.69851 μ m. The high-resolution L -band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4 m telescope. The average [{sup 35}Cl/Fe] abundance in stars with −0.72 < [Fe/H] < 0.20 is [{sup 35}Cl/Fe] = (−0.10 ± 0.15) dex. The mean difference between the [{sup 35}Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16 ± 0.15) dex. The [{sup 35}Cl/Ca] ratio has an offset of ∼0.35 dex above model predictions, suggesting that chemical evolution models are underproducing 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 H ii regions. In one star where both H{sup 35}Cl and H{sup 37}Cl could be measured, a {sup 35}Cl/{sup 37}Cl isotope ratio of 2.2 ± 0.4 was found, consistent with values found in the Galactic ISM and predicted chemical evolution models.

  11. Oak Ridge K-25 Site chlorinated solvent pollution prevention opportunity assessment

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    A pollution prevention opportunity assessment (PPOA) was conducted at the Oak Ridge K-25 Site to identify opportunities to reduce and better manage the use of chlorinated solvents. At the K-25 Site, 67 control areas were examined for their potential use of chlorinated solvents. Of these areas, 27 were found to be using (1) chlorinated solvents for cleaning, degreasing, and lubricating; (2) laboratory standards and solvents; and (3) test medium. Current management practices encourage the identification and use of nonhazardous chemicals, including the use of chlorinated solvents. The main pollution prevention principles are source reduction and recycling, and a number of pollution prevention options based on these principles were identified and evaluated as part of this chlorinated solvent PPOA. Source reduction options evaluated for the K-25 Site include the substitution of chlorinated solvents with nonchlorinated solvents. Recycling was identified for those areas that would benefit most from the reuse of the chlorinated solvents in use. The pollution prevention options that offer the greatest opportunity for success at the K-25 Site are the implementation of substitutes at the 10 control areas using chlorinated solvents for cleaning, degreasing, and lubrication. A change in the process may be all that is needed to eliminate the use of a chlorinated solvent. Once a decision is made to implement a substitution, the information should be communicated to all shops and laboratories. Another option to consider is the installation of recycling units to recycle the large amounts of methylene chloride used in the analytical sampling procedure.

  12. Oak Ridge K-25 Site chlorinated solvent pollution prevention opportunity assessment

    International Nuclear Information System (INIS)

    1994-08-01

    A pollution prevention opportunity assessment (PPOA) was conducted at the Oak Ridge K-25 Site to identify opportunities to reduce and better manage the use of chlorinated solvents. At the K-25 Site, 67 control areas were examined for their potential use of chlorinated solvents. Of these areas, 27 were found to be using (1) chlorinated solvents for cleaning, degreasing, and lubricating; (2) laboratory standards and solvents; and (3) test medium. Current management practices encourage the identification and use of nonhazardous chemicals, including the use of chlorinated solvents. The main pollution prevention principles are source reduction and recycling, and a number of pollution prevention options based on these principles were identified and evaluated as part of this chlorinated solvent PPOA. Source reduction options evaluated for the K-25 Site include the substitution of chlorinated solvents with nonchlorinated solvents. Recycling was identified for those areas that would benefit most from the reuse of the chlorinated solvents in use. The pollution prevention options that offer the greatest opportunity for success at the K-25 Site are the implementation of substitutes at the 10 control areas using chlorinated solvents for cleaning, degreasing, and lubrication. A change in the process may be all that is needed to eliminate the use of a chlorinated solvent. Once a decision is made to implement a substitution, the information should be communicated to all shops and laboratories. Another option to consider is the installation of recycling units to recycle the large amounts of methylene chloride used in the analytical sampling procedure

  13. Chlorine inactivation of fungal spores on cereal grains.

    Science.gov (United States)

    Andrews, S; Pardoel, D; Harun, A; Treloar, T

    1997-04-01

    Although 0.4% chlorine for 2 min has been recommended for surface disinfection of food samples before direct plating for fungal enumeration, this procedure may not be adequate for highly contaminated products. The effectiveness of a range of chlorine solutions was investigated using barley samples artificially contaminated with four different concentrations of Aspergillus flavus. A. niger, A. ochraceus, Eurotium repens, Penicillium brevicompactum P. chrysogenum and Cladosporium cladosporioides. At initial contamination levels greater than 10(4)/g, 0.4% chlorine did not inactivate sufficient spores to produce less than 20% contamination. Of the test fungi, ascospores of E. repens were the most resistant to chlorine inactivation, whereas the conidia of C. cladosporioides were the most sensitive. Rinsing the samples with 70% ethanol improved the effectiveness of the recommended surface disinfection procedure. However, some ethanol appears to permeate into the grains and may inactivate sensitive internal fungi, although a minimal effect only was observed on wheat infected with Alternaria.

  14. Thermodynamic consideration on chlorination of uraniferous phosphorite

    International Nuclear Information System (INIS)

    Itagaki, Kimio; Tozawa, Kazuteru; Taki, Tomihiro; Hirono, Shuichiro.

    1989-01-01

    The uranium ore of low grade which has apatite as a main mineral, but is different from the phosphorite used as the raw material for phosphoric acid production, exists in large amount in South America and Africa continents, and the importance of its effective utilization as future uranium resources is recognized. The Power Reactor and Nuclear Fuel Development Corp. took up the establishment of the treatment techniques to make this ore into resources as the subject of a project, and proposed the process of volatilizing the uranium in the ore as the chloride and recovering it, and at present, it attempts the experiment on the chlorination treatment. In this paper, the thermodynamic examination on the feasibility of this process, the optimum condition for leaving calcium existing in a large amount in the ore as the phosphate without chlorination and recovering only uranium by chlorination and volatilization, the phase reaction equilibrium chart and the calculation method according to thermodynamics concerning the behavior of chlorination of accompanying elements such as iron, silicon and aluminum and the effect of moisture in the ore are reported. (K.I.)

  15. Factorial analysis of the trihalomethanes formation in water disinfection using chlorine

    International Nuclear Information System (INIS)

    Rodrigues, Pedro M.S.M.; Esteves da Silva, Joaquim C.G.; Antunes, Maria Cristina G.

    2007-01-01

    The factors that affect trihalomethane (THM) (chloroform, bromodichloromethane, chlorodibromomethane and bromoform) formation from the chlorination of aqueous solutions of hydrophobic fulvic acids (FA) were investigated in a prototype laboratorial simulation using factorial analysis. This strategy involved a fractional factorial design (16 plus 5 center experiments) of five factors (fulvic acids concentration, chlorine dose, temperature, pH and bromide concentration) and a Box Behnken design (12 plus 3 center experiments) for the detailed analysis of three factors (FA concentration, chlorine dose and temperature). The concentration of THM was determined by headspace analysis by GC-ECD. The most significant factors that affect the four THM productions were the following: chloroform-FA concentration and temperature; bromodichloromethane-FA concentration and chlorine dose; chlorodibromomethane-chlorine dose; and, bromoform-chlorine dose and bromide concentration. Moreover, linear models were obtained for the four THM concentrations in the disinfection solution as function of the FA concentration, chlorine dose and temperature, and it was observed that the complexity of the models (number of significant factors and interactions) increased with increasing bromine atoms in the THM. Also, this study shows that reducing the FA concentration the relative amount of bromated THM increases

  16. Aqueous chemistry of chlorine: chemistry, analysis, and environmental fate of reactive oxidant species

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, R.L.; Carpenter, J.H.

    1982-01-01

    This report reviews (1) the chemistry of chlorine relative to its reactions in fresh, estuarine, and marine waters and the formation of reactive oxidant species; (2) the current status of chemical analysis of reactive chlorine species and chlorine-produced oxidant species relative to analysis of low concentrations (microgram-per-liter range) and determination of accuracy and precision of methods; and (3) the environmental fate of chlorine and chlorine-produced oxidant species.

  17. 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.

  18. Fatal chlorine gas exposure at a metal recycling facility: Case report.

    Science.gov (United States)

    Harvey, Robert R; Boylstein, Randy; McCullough, Joel; Shumate, Alice; Yeoman, Kristin; Bailey, Rachel L; Cummings, Kristin J

    2018-06-01

    At least four workers at a metal recycling facility were hospitalized and one died after exposure to chlorine gas when it was accidentally released from an intact, closed-valved cylinder being processed for scrap metal. This unintentional chlorine gas release marks at least the third such incident at a metal recycling facility in the United States since 2010. We describe the fatal case of the worker whose clinical course was consistent with acute respiratory distress syndrome (ARDS) following exposure to high concentrations of chlorine gas. This case report emphasizes the potential risk of chlorine gas exposure to metal recycling workers by accepting and processing intact, closed-valved containers. The metal recycling industry should take steps to increase awareness of this established risk to prevent future chlorine gas releases. Additionally, public health practitioners and clinicians should be aware that metal recycling workers are at risk for chlorine gas exposure. © 2018 Wiley Periodicals, Inc.

  19. Elaboration of a model of the nuclear fragmentation and application to the method of isotopic separation of projectile fragments

    International Nuclear Information System (INIS)

    Gaimard, J.J.

    1990-10-01

    In this thesis the experimental results on the cross sections for the production of 36 P in the fragmentation of 403 MeV/u 40 Ar on a carbon target are presented. Furthermore some models of the nuclear fragmentation are elaborated and compared by means of experimental data for the production of gold and cerium isotopes in the reaction 12 C+ 209 Bi at 400 MeV/u, of chlorine, sulfur, aluminium, magnesium, and oxygen isotopes in the reactions 40 Ar+ 12 C at 600 MeV/u and 48 Ca+ 9 Be at 212 MeV/u, and of cobalt, manganese, vanadium, and scandium isotopes together with the charge distributions for A=43 and A=44 in the reactions 40 Ar+ 64 Cu at 2 GeV/u and 56 Fe+ 12 C at 600 MeV/u. (HSI)

  20. Investigation of molybdenum pentachloride interaction with chlorine

    International Nuclear Information System (INIS)

    Salyulev, A.B.; Vovkotrub, Eh.G.; Strekalovskij, V.N.

    1993-01-01

    In Raman spectra of molybdenum pentachloride solutions in liquid chlorine lines were recorded in case of 397, 312, 410, 217 and 180 cm - 1 vibrations of ν 1 (A 1 '), ν 2 (A 1 '), ν 5 (E'), ν 6 (E') and ν 8 (E'') monomer (symmetry D 3h ) molecules of MoCl 5 . Interaction of molten molybdenum pentachloride with chlorine at increased (up to 6 MPa) pressures of Cl 2 was studied. In Raman spectra of its vapour distillation in liquid chlorine alongside with MoCl 5 lines appearance of new lines at 363 and 272 cm -1 , similar in their frequency to the ones calculated for the vibrations ν 1 (A 1g ) and ν 2 (E g ) of MoCl 6 molecules (symmetry O h ), was observed

  1. Chlorin photosensitizers sterically designed to prevent self-aggregation.

    Science.gov (United States)

    Uchoa, Adjaci F; de Oliveira, Kleber T; Baptista, Mauricio S; Bortoluzzi, Adailton J; Iamamoto, Yassuko; Serra, Osvaldo A

    2011-11-04

    The synthesis and photophysical evaluation of new chlorin derivatives are described. The Diels-Alder reaction between protoporphyrin IX dimethyl ester and substituted maleimides furnishes endo-adducts that completely prevent the self-aggregation of the chlorins. Fluorescence, resonant light scattering (RLS) and (1)H NMR experiments, as well as X-ray crystallographic have demonstrated that the configurational arrangement of the synthesized chlorins prevent π-stacking interactions between macrocycles, thus indicating that it is a nonaggregating photosensitizer with high singlet oxygen (Φ(Δ)) and fluorescence (Φ(f)) quantum yields. Our results show that this type of synthetic strategy may provide the lead to a new generation of PDT photosensitizers.

  2. UASB reactor effluent disinfection by ozone and chlorine

    NARCIS (Netherlands)

    Ribeiro da Silvia, G.H.; Bruning, H.; Gerrity, D.; Daniel, L.A.

    2015-01-01

    This research studied the sequential ozone and chlorine process with respect to, the inactivation of indicator bacteria and the formation of ozone disinfection byproducts in sanitary wastewater effluent. The applied ozone doses were 5, 8 and 10 mg.O3.L-1, followed by chlorine doses of 10, 20 and 30

  3. State of the art on cyanotoxins in water and their behaviour towards chlorine.

    Science.gov (United States)

    Merel, Sylvain; Clément, Michel; Thomas, Olivier

    2010-04-01

    The occurrence of cyanobacterial blooms is drastically increasing in temperate countries and drinking water resources are threatened. As a result, cyanotoxins should be considered in water treatment to protect human health. This study presents a state of the art on cyanotoxins in water and their behaviour towards chlorination, a common drinking water disinfection process. Chlorination efficiency on cyanotoxins alteration depends on pH, chlorine dose and oxidant nature. Microcystins and cylindrospermopsin are efficiently transformed by chlorine, with respectively 6 and 2 by-products identified. In addition, chlorination of microcystins and cylindrospermopsin is associated with a loss of acute toxicity. Even though they have been less investigated, saxitoxins and nodularins are also altered by chlorine. For these toxins, no by-products have been identified, but the chlorinated mixture does not show acute toxicity. On the contrary, the fact that anatoxin-a has a very slow reaction kinetics suggests that this toxin resists chlorination. Copyright 2009 Elsevier Ltd. All rights reserved.

  4. Non-destructive analysis of chlorine in fly ash cement concrete

    International Nuclear Information System (INIS)

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

    2009-01-01

    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.

  5. Non-destructive analysis of chlorine in fly ash cement concrete

    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; Garwan, M.A.; Nagadi, M.M. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, 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); Khateeb-ur-Rehman [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2009-08-11

    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. Stratospheric chlorine injection by volcanic eruptions - HCl scavenging and implications for ozone

    Science.gov (United States)

    Tabazadeh, A.; Turco, R. P.

    1993-01-01

    Because the output of volatile chlorine during a major volcanic event can greatly exceed the annual anthropogenic emissions of chlorine to the atmosphere, the fate of volcanic chlorine must be known. Although numerous observations have shown that volcanoes do not significantly contribute to the stratospheric chlorine burden, no quantitative explanation has been published. Hydrogen chloride (HCl) scavenging processes during the early phases of a volcanic eruption are discussed. A plume dynamics and thermodynamics model is used to show that HCl removal in condensed supercooled water can reduce HCl vapor concentrations by up to four orders of magnitude, preventing substantial stratospheric chlorine injection.

  7. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Removal of trihalomethane from chlorinated seawater using gamma radiation.

    Science.gov (United States)

    Rajamohan, R; Natesan, Usha; Venugopalan, V P; Rajesh, Puspalata; Rangarajan, S

    2015-12-01

    Chlorine addition as a biocide in seawater results in the formation of chlorination by-products such as trihalomethanes (THMs). Removal of THMs is of importance as they are potential mutagenic and carcinogenic agents. In this context, a study was conducted that used ionizing radiation to remove THMs from chlorinated (1, 3, and 5 mg/L) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation. Bromoform (BF) showed a faster rate of degradation as compared to other halocarbons such as bromodichloromethane (BDCM) and dibromochloromethane (DBCM). In chlorine-dosed seawater, total irradiation dose of 0.4 to 5 kGy caused percentage reduction in the range of 6.9 to 76.7%, 2.3 to 99.6%, and 45.7 to 98.3% for BDCM, DBCM, and BF, respectively. During the irradiation process, pH of the chlorinated seawater decreased with increase in the absorbed dose; however, no change in total organic carbon (TOC) was observed. The results show that gamma dose of 2.5 kGy was adequate for maximum degradation of THM; but for complete mineralization, higher dose would be required.

  9. Determination of chlorine in graphite by combustion-ion chromatography

    International Nuclear Information System (INIS)

    Chen Lianzhong; Watanabe, Kazuo; Itoh, Mitsuo.

    1995-09-01

    A combustion/ion chromatographic method has been studied for the sensitive determination of chlorine in graphite. A graphite sample was burnt at 900degC in a silica reaction tube at an oxygen flow rate of 200 ml/min. Chlorine evolved was absorbed in 20 ml of a 0.1 mM sodium carbonate solution. The solution was evaporated to dryness. The residue was dissolved with a small volume of water. Chlorine in the solution was determined using ion chromatography. The method was applied to JAERI graphite certified reference materials and practical graphite materials. The detection limit was about 0.8 μgCl/g for a 2.0 g sample. The precision was about 2.5% (relative standard deviation) for samples with chlorine content of 70 μg/g level. The method is also usable for coal samples. (author)

  10. Sequential and Simultaneous Applications of UV and Chlorine for Adenovirus Inactivation.

    Science.gov (United States)

    Rattanakul, Surapong; Oguma, Kumiko; Takizawa, Satoshi

    2015-09-01

    Adenoviruses are water-borne human pathogens with high resistance to UV disinfection. Combination of UV treatment and chlorination could be an effective approach to deal with adenoviruses. In this study, human adenovirus 5 (HAdV-5) was challenged in a bench-scale experiment by separate applications of UV or chlorine and by combined applications of UV and chlorine in either a sequential or simultaneous manner. The treated samples were then propagated in human lung carcinoma epithelial cells to quantify the log inactivation of HAdV-5. When the processes were separate, a fluence of 100 mJ/cm(2) and a CT value of 0.02 mg min/L were required to achieve 2 log inactivation of HAdV-5 by UV disinfection and chlorination, respectively. Interestingly, synergistic effects on the HAdV-5 inactivation rates were found in the sequential process of chlorine followed by UV (Cl2-UV) (p simultaneous application of UV/Cl2. This implies that a pretreatment with chlorine may increase the sensitivity of the virus to the subsequent UV disinfection. In conclusion, this study suggests that the combined application of UV and chlorine could be an effective measure against adenoviruses as a multi-barrier approach in water disinfection.

  11. Chlorination of uranium oxides with CCl4 using a mechanochemical method

    Science.gov (United States)

    Kitawaki, Shinichi; Nagai, Takayuki; Sato, Nobuaki

    2013-08-01

    A chlorination method for uranium oxides at low temperature was investigated by using a mechanochemical method. In particular, the possibility of the chlorination of uranium oxides, such as UO2 and U3O8, via mechanochemical reaction with CCl4 was studied using a planetary ball mill. Mechanochemical experiments were conducted to evaluate the effect of milling time, CCl4/uranium oxide molar ratio, and revolution speed on the reaction. The synthesized products were then subjected to X-ray diffraction analysis, and it was found that the chlorination of U3O8 with CCl4 to UOCl2, UCl4, and U2O2Cl5 proceeded. However, the chlorination reaction could not be observed when using UO2 powder as the raw material. The chlorination reaction could not be observed when using UO2 powder as the raw material. The chlorination of U3O8 with CCl4 to form UOCl2, UCl4, and U2O2Cl5 via mechanochemical reaction occurs at room temperature. The ratio of chlorination increases with milling time when the appropriate amount of CCl4 is employed. However, the use of excess liquid CCl4 decreases the mechanochemical effect.

  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. Chlorine dioxide as biocide to prevent biofouling in the hydro technical structures at KKNPP

    International Nuclear Information System (INIS)

    Ganesh, S.; Selvaraj, S.; Balasubramanian, M.R.; Selvavinayagam, P.; Sundar, R.S.

    2008-01-01

    Chlorination is envisaged in the sea water systems of KKNPP to control macro and micro bio-fouling of underwater structures and equipments. KKNPP intake and the fore bay structures are shown in detail. The sodium hypo chlorite required for chlorination is produced in the electro chlorination plant at site by the electrolysis of sea water. It is added in the sea water at the intake structure, tunnels and fore bay on continuous as well as periodic basis. The sea water to chlorination plant is supplied by the pumps located at the main pump house. Chlorination of sea water system by electro-chlorination is possible only after pump house flooding and commissioning of electro-chlorination plant. So for the period from breach of temporary dyke till commissioning of electro chlorination plant, chlorination by temporary method has to be done to prevent the bio-fouling of underwater structures and equipments. The flooding of the pump house subsequent to breach of temporary dyke is done

  14. Analysis of residual chlorine in simple drinking water distribution system with intermittent water supply

    Science.gov (United States)

    Goyal, Roopali V.; Patel, H. M.

    2015-09-01

    Knowledge of residual chlorine concentration at various locations in drinking water distribution system is essential final check to the quality of water supplied to the consumers. This paper presents a methodology to find out the residual chlorine concentration at various locations in simple branch network by integrating the hydraulic and water quality model using first-order chlorine decay equation with booster chlorination nodes for intermittent water supply. The explicit equations are developed to compute the residual chlorine in network with a long distribution pipe line at critical nodes. These equations are applicable to Indian conditions where intermittent water supply is the most common system of water supply. It is observed that in intermittent water supply, the residual chlorine at farthest node is sensitive to water supply hours and travelling time of chlorine. Thus, the travelling time of chlorine can be considered to justify the requirement of booster chlorination for intermittent water supply.

  15. Temperature sensitivity indicates that chlorination of organic matter in forest soil is primarily biotic.

    Science.gov (United States)

    Bastviken, David; Svensson, Teresia; Karlsson, Susanne; Sandén, Per; Oberg, Gunilla

    2009-05-15

    Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 degrees C. Minimum rates were found at high temperatures (50 degrees C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 degrees C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 degrees C and under oxic conditions at 50 degrees C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.

  16. 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.

  17. Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

    International Nuclear Information System (INIS)

    Fogel, M.M.; Taddeo, A.R.; Fogel, S.

    1986-01-01

    Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14 CO 2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO 2 . Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations

  18. Evaluation of Perchlorate Sources in the Rialto-Colton and Chino California Subbasins using Chlorine and Oxygen Isotope Ratio Analysis

    Science.gov (United States)

    2015-03-01

    matches, air bags , chlorine bleach, safety flares, perchloric acid, and chlorate herbicides (Trumpholt et al., 2005; Aziz et al., 2006, 2008). Based...L, assuming no losses to biodegradation or other removal processes. Additional information on Atacama NO3- fertilizers as a source of ClO4- can be...in each well), the IX columns were removed from the each well, sealed in Zip-Loc type bags , placed at 4oC (or on ice), and shipped to the UIC EIGL

  19. 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 .

  20. Structural and optical properties of chlorinated plasma polymers

    International Nuclear Information System (INIS)

    Turri, Rafael; Davanzo, Celso U.; Schreiner, Wido; Dias da Silva, José Humberto; Appolinario, Marcelo Borgatto; Durrant, Steven F.

    2011-01-01

    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 C , which was varied from 0 to 80%. Deposition rates of 80 nm min −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 ∼ 47 at.% for R C ≥ 40%. The refractive index and optical gap, E 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 ∼ 40° to ∼ 77°.

  1. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    Energy Technology Data Exchange (ETDEWEB)

    Cassayre, L., E-mail: cassayre@chimie.ups-tlse.fr [Laboratoire de Genie Chimique (LGC), Departement Procedes Electrochimiques, CNRS-UMR 5503, Universite de Toulouse III - Paul Sabatier, 31062 Toulouse (France); Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P. [European Commission, JRC, Institute for Transuranium Elements, Postfach 2340, 76125 Karlsruhe (Germany)

    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{sub 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{sub 3} alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl{sub 2}/UAl{sub 3} molar ratio, providing complete chlorination of the alloy without formation of volatile UCl{sub 5} and UCl{sub 6}. The results showed high efficient chlorination at a temperature of 150 deg. C.

  2. Recovery of actinides from actinide-aluminium alloys by chlorination: Part I

    International Nuclear Information System (INIS)

    Cassayre, L.; Soucek, P.; Mendes, E.; Malmbeck, R.; Nourry, C.; Eloirdi, R.; Glatz, J.-P.

    2011-01-01

    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 deg. C.

  3. Preparation of 1,1,2,2-tetrachloroethane and trichloroethylene labelled with radioactive chlorine

    International Nuclear Information System (INIS)

    Smirnova, G.E.; Shalygin, V.A.; Zel'venskij, Ya.D.; Prosyanov, N.N.

    1980-01-01

    The chemical synthesis of 1,1,2,2-tetrachloroethane is carried out. 1,2,2,2-tetrachloroethane is labelled with radioactive chlorine by chlorinating the mixture of cis-, transisomeres of dichlorethylene with elementary chlorine. Trichloroethylene labelled with radioactive chlorine is prepared by the effect of alkali alcohol solution on radioactive 1,1,2,2-tetrachloroethane

  4. The removal of phenols from oily wastewater by chlorine dioxide

    OpenAIRE

    Hsu, Chung-Jung

    1988-01-01

    Treatability studies were performed on oily wastewaters produced by petroleum and canning industries. Chlorine dioxide was used for the removal of phenolic compounds from these oily wastewaters. Most of phenolic compounds can be destroyed by chlorine dioxide within 15 minutes if CI02-to-phenol ratios of higher than 5.0 are provided. Factors such as pH, temperature, and COD have little effect on phenol removal. The effectiveness of chlorine dioxide treatment depends critic...

  5. Chlorine gas processing of oxide nuclear fuel particles containing thorium

    International Nuclear Information System (INIS)

    Knotik, K.; Bildstein, H.; Falta, G.; Wagner, H.

    Experimental studies on the chloride extraction and separation of U and Th from coated Th--U oxide particles are reported. After a description of the chlorination equipment and the experimental procedures, the results are discussed. The yield of U is determined as a function of the reaction temperature. The results of a thermogravimetric analysis of the chlorination of uranium carbide and thorium carbides are reported and used to establish the reaction mechanism for the chlorination

  6. Organic photochemical reactions on solid surfaces: Enrichment and separation of isotopes. Final report. SBIR-1988, Phase 2

    International Nuclear Information System (INIS)

    Ruderman, W.; Fehlner, J.; Spencer, J.

    1988-01-01

    The objectives of the Phase II program were to: (1) investigate organic photochemical reactions on solid porous silica surfaces, (2) utilize the magnetic isotope effect to develop a (13)C enrichment process using a fluidized bed reactor, and (3) investigate the possibility of enrichment of heavier isotopes having a nuclear spin. Although researchers were able to demonstrate a continuous fluidized bed (13)C enrichment process, analysis showed that the process could not compete with low temperature distillation of CO because of the high cost of the starting material, dibenzylketone (DBK), and the difficulty of converting the photochemical decomposition products back to DBK. However, the process shows promise for the separation of heavier isotopes such as (29)Si. The photochemical studies led to the discovery that the selectivity for terminal chlorination of alkanes can be increased more than 25 fold by sorbing the alkanes on ZSM-5 zeolites in a fluidized bed. The selectivity is ascribed to the presence of interfaces within the crystals

  7. Bacterial oxidation of low-chlorinated compounds under anoxic conditions

    NARCIS (Netherlands)

    Dijk, J.A.

    2005-01-01

    Chlorinated hydrocarbons belong to the most frequently encountered contaminants in soil and groundwater. Many of them were found to be toxic and recalcitrant, which causes a potential threat to the environment. Therefore, it is of great importance that sites contaminated with chlorinated

  8. Radioimmunoassay for chlorinated dibenzo-p-dioxins

    International Nuclear Information System (INIS)

    Albro, P.W.; Chae, K.; Luster, M.I.; Mckinney, J.D.

    1980-01-01

    The invention provides a double-antibody radioimmunoassay method for the determination of chlorinated dibenzo-p-dioxins, particularly, 2,3,7,8-tetrachlorodibenzo-p-dioxin, in environmental samples including animal tissues such as monkey liver and adipose tissues. The limit of detection is approximately 25 picograms for 2,3,7,8-tetrachlorodibenzo-pdioxin. Assuming an appropriate cleanup procedure is used, chlorinated dibenzofurans are the only likely interferences, and these can be distinguished through the use of two antisers of different dibenzo-furan/dibenzodioxin selectivities. The invention includes the preparation of a reproducible antigen, an appropriate radiolabeled hapten, and effective sample extracts. A feature of the assay method is the use of a nonionic detergent (e.g., ''cutscum'' or ''triton x-305'') to solubilize the extremely hydrophobic dibenzo-p-dioxins in a manner permitting their binding by antibodies. The immunoassay is applicable to screening samples in order to minimize the demand for mass spectrometric screening, and to routine monitoring for exposure to known chlorinated dibenzo-p-dioxins in potentially contaminated environments

  9. Chlorination of zirconium (0001) surface: A first-principles study.

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eunja [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Physics and Astronomy; Weck, Philippe F [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Borjas, Rosendo [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Chemistry; Poineau, Frederic [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Chemistry

    2017-01-01

    Here, the mechanisms and energetics of Zr(0001) surface chlorination by dissociative adsorption of gaseous Cl2, and associated speciation and surface degradation processes, have been investigated within the framework of density functional theory. Chlorination of Zr(0001) is predicted to be exothermic by ~3 eV/Cl for dissociative adsorption of a single Cl2 molecule, followed by exothermic chlorination to 1ML and 2 ML under Cl-rich conditions, with respective energy gains of 1.93 and 2.79 eV/Cl. Calculations also show that exfoliation of the top Cl-Zr-Cl sandwich layers is exothermic and most energetically favorable, and can thus be considered as a leading mechanism for Zr(0001) surface dissolution. Consistent with experimental findings, formation of ZrCl4 molecular products is also found to be dominant during Zr(0001) chlorination.

  10. Chlorination of zirconium (0001) surface: A first-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E. [Univ. of Nevada, Las Vegas, NV (United States). Department of Physics and Astronomy; Weck, Philippe F [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Poineau, F. [Univ. of Nevada, Las Vegas, NV (United States). Department of Chemistry; Paviet, P. [Dept. of Energy (DOE), Washington DC (United States)

    2016-12-13

    The mechanisms and energetics of Zr(0001) surface chlorination by dissociative adsorption of gaseous Cl2, and associated speciation and surface degradation processes, have been investigated within the framework of density functional theory. Chlorination of Zr(0001) is predicted to be exothermic by 3 eV/Cl for dissociative adsorption of a single Cl2 molecule, followed by exothermic chlorination to 1ML and 2 ML under Cl-rich conditions, with respective energy gains of 1.93 and 2.79 eV/Cl. Calculations also show that exfoliation of the top Cl-Zr-Cl sandwich layers is exothermic and most energetically favorable, and can thus be considered as a leading mechanism for Zr(0001) surface dissolution. Finally, consistent with experimental findings, formation of ZrCl4 molecular products is also found to be dominant during Zr(0001) chlorination.

  11. Optimization of Chlorination Process for Mature Leachate Disinfection Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Hamzeh Ali Jamali1

    2014-06-01

    Full Text Available Background: leachate from landfill contains high level of microbial pathogens which is considered as one of the most important threats for the environment. One of the common and simple methods for water and wastewater disinfection is chlorination, but it rarely has been used for leachate disinfection. The objective of this study was evaluating the efficiency of chlorine for leachate disinfection and optimization of the effect of concentration and contact time on the death of total and fecal coliforms, as a microbial contamination index. Methods: In this descriptive-analysis study, microbial indices monitoring in leachates initiated from landfill of Qazvin city were conducted for one year. After pre-tests, the range of chlorine concentration and contact time on the inactivation of microbial indices were determined. Central composite design (CCD and response surface methodology (RSM were applied to optimize chlorine concentration and contact time parameters effect on microbial inactivation. 13 runs of tests were performed on samples. Tests were included BOD, COD, total and fecal coliforms. All analytical experiments were according to the standard methods for the examination of water and wastewater. Results: Results of the study showed that microbial indices had relatively high sensitivity to inactivation by chlorination, which in the chlorine concentration of 2 mg/L and contact time of 9 min, and chlorine concentration of 0.5 mg/L and contact time of 12 min, 100% of total and fecal coliforms inactivated, respectively. The RSM method was used for analysis of bacterial inactivation. Analyses showed that in contact time of 9.4 min and chlorine concentration of 2.99 mg/L, the inactivation efficiency of total and fecal coliforms were 89.16% and 100%, respectively. Conclusions: Chlorine could be used for leachate disinfection. However, in high concentrations of organic matter in leachates, due to production potential of chlorination by-products, health

  12. Evaluation of sea water chlorine demand in condenser cooling water at TAPS 1 and 2

    International Nuclear Information System (INIS)

    Papachan, Deepa; Gupta, P.K.; Patil, D.P.; Save, C.B.; Anilkumar, K.R.

    2008-01-01

    To prevent microbiological growth in the condenser tubes, condenser cooling water chlorination is very important. For effective chlorination, chlorine dose rate and frequency of dosing has to be determined on the basis of sea water chlorine demand. TAPS 1 and 2 is located near Arabian sea and draws water from this sea for its condenser cooling. The present practice of chlorine dosing at TAPS 1 and 2, based on the analysis carried out by GE in 1969, is 2500 kg/day/CWpump and 90 kg/day/SSWpump for a contact period of 25 minutes. Normal frequency of dosing is once per 8 hour and booster dose is once in a week at the same rate for 1 hour. The criteria of effective chlorination is to get residual chlorine of 2-3 ppm at the condenser water box outlet during chlorination at water box inlet/CW pump suction header in the recommended dose rate. The other option of chlorination was continuous dosing to get 0.5 ppm residual chlorine. This option has its own limitations as it is more expensive and also that micro organisms get immune to chlorine eventually due to continuous dosing. Nevertheless higher chlorine dosing is detrimental to AI-brass condenser tubes. Therefore the second option was not adopted at TAPS 1 and 2. Tarapur Atomic Power Station-1 is in the process of replacement of condenser tubes due to frequent condenser tube failures in the recent years. It was essential to analyse the present sea water chlorine demand and re-determine the chlorine dose rate because of development of industries under Maharashtra Industrial Development Corporation (MIDC) and simultaneous population growth around this area over a period of three decades. This paper discusses the experimental observations regarding significant change in sea water chlorine demand over this period and the effect of seasonal changes on sea water chlorine demand. (author)

  13. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    International Nuclear Information System (INIS)

    Vacchi, Francine Inforçato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre; Ormond, Alexandra B.; Freeman, Harold S.; Zocolo, Guilherme Julião; Zanoni, Maria Valnice Boldrin; Umbuzeiro, Gisela

    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: ► Aqueous solutions of Disperse Red 1 were treated with chlorine. ► The chlorination products of Disperse Red 1 were identified using LC–ESI-MS/MS. ► Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. ► The chlorinated dye was more mutagenic than the dye itself. ► Chlorination should be avoided in effluents containing azo-dyes.

  14. The chlorination kinetics of zirconium dioxide mixed with carbon black

    International Nuclear Information System (INIS)

    Movahedian, A.; Raygan, Sh.; Pourabdoli, M.

    2011-01-01

    In this research, the effects of chlorine gas at different chlorine partial pressures and carbon concentrations on the carbochlorination of zirconia were studied. It was found that in briquettes containing 18.7 %wt carbon, in a chlorine partial pressure range of 0.25-0.75 atm and for a reacted fraction of less than 0.7, the chemical reaction model was dominant for the carbochlorination process of zirconia. The order of reaction into chlorine gas (n) in this situation was 0.57. Moreover, the best weight ratio of carbon to zirconia was 40/60. In this case, the activation energy of the reaction was 209.9 kJ mol -1 in a temperature range of 1023-1223 K, and the dominant model was the chemical reaction model.

  15. Chlorine determination in (U, Pu)C fuel by total reflection X-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Misra, Nand Lal; Dhara, Sangita; Mudher, Khush Dev Singh; Aggarwal, Suresh K.; Thakur, Uday Kumar; Shah, Dipti; Sawant, R.M.; Ramakumar, K.L.

    2007-01-01

    A Total Reflection X-ray Fluorescence (TXRF) method for the determination of chlorine in (U,Pu)C has been developed. The method involves calibration of the instrument with standard solutions and validation of TXRF determination of chlorine using synthetic standard solutions. Cl K α line excited with W L α source was used for TXRF determinations of chlorine. Chlorine present in trace amounts in (U,Pu)C samples was first separated by pyro hydrolysis. The evolved chlorine, in form of HCl, was collected in 5 mM NaOH solution. This solution was analyzed for chlorine by Total Reflection X-ray Fluorescence Spectrometry using cobalt as an internal standard. The TXRF detection limit of chlorine was found to be 3.6 pg with sample size of 30 μL. In order to assess the applicability of TXRF method for chlorine determinations in other nuclear materials, one U 3 O 8 trace element standard was also analyzed for chlorine in similar way. The precision of the method was found to be 25% (1 σ) at ng level in most of the cases. (author)

  16. Kinetic study on the chlorination of β-spodumene for lithium extraction with Cl2 gas

    International Nuclear Information System (INIS)

    Barbosa, L.I.; Valente, N.G.; González, J.A.

    2013-01-01

    Highlights: ► β-Spodumene was chlorinated to extract lithium with pure chlorine. ► The kinetics of the chlorination was studied in the range of 1000–1100 °C. ► Cl 2 flow rate, sample mass, and Cl 2 partial pressure were the operating variables. ► Experimental data were best fitted by the sequential nucleation and growth model. - Abstract: In this paper, the kinetics chlorination of β-spodumene for the extraction of lithium has been studied using gaseous chlorine as chlorinating agent. The effect of chlorine flow rate, temperature, mass of the sample, and partial pressure of Cl 2 was investigated. The study of the effect of chlorine flow rate indicated that the chlorination of β-spodumene may be carried out in the presence of active chlorinating species The chlorine partial pressure was found to have an appreciable effect on the system reactivity. The temperature was found to be the most important variable affecting the reaction rate. The β-spodumene chlorination process by Cl 2 was characterized by an apparent activation energy of about 359 kJ/mol in the range from 1000 to 1100 °C. Reaction was of non-catalytic gas–solid nature and experimental data fitted the sequential nucleation and growth model

  17. Short-term organic carbon migration from polymeric materials in contact with chlorinated drinking water.

    Science.gov (United States)

    Mao, Guannan; Wang, Yingying; Hammes, Frederik

    2018-02-01

    Polymeric materials are widely used in drinking water distribution systems. These materials could release organic carbon that supports bacterial growth. To date, the available migration assays for polymeric materials have not included the potential influence of chlorination on organic carbon migration behavior. Hence, we established a migration and growth potential protocol specifically for analysis of carbon migration from materials in contact with chlorinated drinking water. Four different materials were tested, including ethylene propylene dienemethylene (EPDM), poly-ethylene (PEX b and PEX c) and poly-butylene (PB). Chlorine consumption rates decreased gradually over time for EPDM, PEXc and PB. In contrast, no free chlorine was detected for PEXb at any time during the 7 migration cycles. Total organic carbon (TOC) and assimilable organic carbon (AOC) was evaluated in both chlorinated and non-chlorinated migrations. TOC concentrations for EPDM and PEXb in chlorinated migrations were significantly higher than non-chlorinated migrations. The AOC results showed pronounced differences among tested materials. AOC concentrations from chlorinated migration waters of EPDM and PB were higher compared to non-chlorinated migrations, whereas the opposite trend was observed for PEXb and PEXc. There was also a considerable difference between tested materials with regards to bacterial growth potential. The results revealed that the materials exposed to chlorine-influenced migration still exhibited a strong biofilm formation potential. The overall results suggested that the choice in material would make a considerable difference in chlorine consumption and carbon migration behavior in drinking water distribution systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Immobilization of chlorine dioxide modified cells for uranium absorption

    International Nuclear Information System (INIS)

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

    2014-01-01

    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(ClO 2 ), 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 UO 2 2+ ions or in a low concentration system to purify UO 2 2+ contaminated water thoroughly, and could be repeatedly used in multiple adsorption-desorption cycles with about 90% adsorption capacity maintained after seven cycles. - Highlights: • Chlorine dioxide 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. • The chlorine dioxide modified cells were further immobilized by carboxymethylcellulose to improve their reusability

  19. Chlorine loss and mass loss from polyvinylchloride and polyvinylidenchloride under the electron beam

    International Nuclear Information System (INIS)

    Lindberg, K.A.H.; Bertilsson, H.E.

    1985-01-01

    The loss of chlorine during the irradiation of PVC and PVDC in the electron microscope has been measured by the decay of the X-ray chlorine Kα signal. A number of factors affecting the measured beam damage curves have been considered and the experimental errors reduced to +- 10%. The results show that the chlorine decay curves can be best described by the sum of two exponentials, corresponding to the two different chlorine decay processes, these being: the dehydrochlorination of the polymer molecules and the dehydrochlorination of the polyene structure formed by the beam damage. The higher initial chlorine content of PVDC compared to PVC will result in a larger amount of chlorine atoms reacting with the polyene structure, which is more stable in the electron beam than the undamaged polymer. The chlorine loss, measured by X-ray analysis, has been compared to the mass loss, measured by energy loss analysis, and also with the volume changes of isolated spherical PVC particles. It has been concluded that the mass loss is almost entirely due to chlorine loss and that the residual structure has a density similar to the undamaged PVC. (author)

  20. Matrix separation by chelation to prepare biological materials for isotopic zinc analysis by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Durrant, S.F.; Krushevska, A.; Amarasiriwardena, D.; Argentine, M.D.; Romon-Guesnier, S.; Barnes, R.M.

    1994-01-01

    Following an evaluation of three chelating resins [Chelex-100, poly(dithiocarbamate) (PDTC) and carboxymethylated poly(ethyleneimine)-poly(methylenepolyphenylene) isocyanate (CPPI)], a procedure was established with the last of these for the separation of Zn from biological matrix elements prior to 70 Zn: 68 Zn isotopic analysis by inductively coupled plasma mass spectrometry (ICP-MS). The method was verified by establishing Zn recoveries and by determining its effectiveness in removing Cl and Na from buffered test solutions. Calcium, Na, and Zn concentration data were determined by inductively coupled plasma atomic emission spectrometry. Chlorine was measured by electrothermal vaporization ICP-MS. The efficacy of the technique was demonstrated by the determination of zinc isotope ratios in bovine milk and human urine. (Author)

  1. Chlorine disinfection of grey water for reuse: effect of organics and particles.

    Science.gov (United States)

    Winward, Gideon P; Avery, Lisa M; Stephenson, Tom; Jefferson, Bruce

    2008-01-01

    Adequate disinfection of grey water prior to reuse is important to prevent the potential transmission of disease-causing microorganisms. Chlorine is a widely utilised disinfectant and as such is a leading contender for disinfection of grey water intended for reuse. This study examined the impact of organics and particles on chlorine disinfection of grey water, measured by total coliform inactivation. The efficacy of disinfection was most closely linked with particle size. Larger particles shielded total coliforms from inactivation and disinfection efficacy decreased with increasing particle size. Blending to extract particle-associated coliforms (PACs) following chlorine disinfection revealed that up to 91% of total coliforms in chlorinated grey water were particle associated. The organic concentration of grey water affected chlorine demand but did not influence the disinfection resistance of total coliforms when a free chlorine residual was maintained. Implications for urban water reuse are discussed and it is recommended that grey water treatment systems target suspended solids removal to ensure removal of PACs prior to disinfection.

  2. 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.

  3. Chlorination of uranium oxides with CCl4 using a mechanochemical method

    International Nuclear Information System (INIS)

    Kitawaki, Shinichi; Nagai, Takayuki; Sato, Nobuaki

    2013-01-01

    Highlights: • UCl 4 or UOCl 2 could be synthesized from U 3 O 8 with CCl 4 by using a planetary ball mill. • The chlorination could not be observed when using UO 2 powder as the starting material. • Extension of milling time was effective for chlorinating U 3 O 8 with the appropriate amount of CCl 4 . -- Abstract: A chlorination method for uranium oxides at low temperature was investigated by using a mechanochemical method. In particular, the possibility of the chlorination of uranium oxides, such as UO 2 and U 3 O 8 , via mechanochemical reaction with CCl 4 was studied using a planetary ball mill. Mechanochemical experiments were conducted to evaluate the effect of milling time, CCl 4 /uranium oxide molar ratio, and revolution speed on the reaction. The synthesized products were then subjected to X-ray diffraction analysis, and it was found that the chlorination of U 3 O 8 with CCl 4 to UOCl 2 , UCl 4 , and U 2 O 2 Cl 5 proceeded. However, the chlorination reaction could not be observed when using UO 2 powder as the raw material

  4. Effect of silica fume addition on the PGNAA measurement of chlorine in concrete

    International Nuclear Information System (INIS)

    Naqvi, A.A.; Maslehuddin, M.; Garwan, M.A.; Nagadi, M.M.; Al-Amoudi, O.S.B.; Raashid, M.; Khateeb-ur-Rehman

    2010-01-01

    Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis (PGNAA) technique. Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. This may result in an improvement in detection limit of chlorine in SF-based concrete in PGNAA studies. Particularly for chlorine detection using 6.11 and 6.62 MeV prompt gamma-rays that strongly interfere with 6.42 MeV prompt gamma-rays from calcium. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.2-3.0 wt% chlorine was measured through yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV chlorine gamma-rays using PGNAA technique. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration (MDC) of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement. The MDC of chlorine in SF-based concrete through 6.11 MeV, and 6.62 MeV chlorine gamma-rays was found to be improved as compared to those in plain concrete and concrete mixed with fly ash cement.

  5. Effect of silica fume addition on the PGNAA measurement of chlorine in concrete

    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; Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Garwan, M.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Nagadi, M.M. [Center for Engineering Research, 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); Raashid, M.; Khateeb-ur-Rehman [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2010-03-15

    Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to Portland cement in concrete to prevent reinforcement steel corrosion in concrete. Further preventive measure against reinforcement steel corrosion require monitoring of chloride salts concentration in concrete using non-destructive techniques, such as the prompt gamma-ray neutron activation analysis (PGNAA) technique. Due to interferences between gamma-rays from chlorine and calcium in PGNAA technique, detection limit of chlorine in concrete strongly depends upon calcium concentration in concrete. SF mainly contains silica and its addition to cement concrete reduces overall concentration of calcium in concrete. This may result in an improvement in detection limit of chlorine in SF-based concrete in PGNAA studies. Particularly for chlorine detection using 6.11 and 6.62 MeV prompt gamma-rays that strongly interfere with 6.42 MeV prompt gamma-rays from calcium. In this study, SF was added to Portland cement to prevent concrete reinforcement steel from corrosion. The chlorine concentration in SF cement concrete specimens containing 0.2-3.0 wt% chlorine was measured through yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV chlorine gamma-rays using PGNAA technique. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the gamma-ray yield calculated through the Monte Carlo simulations. Further the minimum detectable concentration (MDC) of chlorine in SF cement concrete was calculated and compared with the MDC values of chlorine in plain concrete and concrete mixed with fly ash cement. The MDC of chlorine in SF-based concrete through 6.11 MeV, and 6.62 MeV chlorine gamma-rays was found to be improved as compared to those in plain concrete and concrete mixed with fly ash cement.

  6. 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)....

  7. 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.

  8. Dehalogenation of Chlorinated Hydroxybiphenyls by Fungal Laccase

    Science.gov (United States)

    Schultz, Asgard; Jonas, Ulrike; Hammer, Elke; Schauer, Frieder

    2001-01-01

    We have investigated the transformation of chlorinated hydroxybiphenyls by laccase produced by Pycnoporus cinnabarinus. The compounds used were transformed to sparingly water-soluble colored precipitates which were identified by gas chromatography-mass spectrometry as oligomerization products of the chlorinated hydroxybiphenyls. During oligomerization of 2-hydroxy-5-chlorobiphenyl and 3-chloro-4-hydroxybiphenyl, dechlorinated C—C-linked dimers were formed, demonstrating the dehalogenation ability of laccase. In addition to these nonhalogenated dimers, both monohalogenated and dihalogenated dimers were identified. PMID:11526052

  9. Thermodynamic analysis of the selective chlorination of electric arc furnace dust

    International Nuclear Information System (INIS)

    Pickles, C.A.

    2009-01-01

    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.

  10. 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.

  11. 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.

  12. Feasibility study of the separation of chlorinated films from plastic packaging wastes.

    Science.gov (United States)

    Reddy, Mallampati Srinivasa; Yamaguchi, Takefumi; Okuda, Tetsuji; Tsai, Tsung-Yueh; Nakai, Satoshi; Nishijima, Wataru; Okada, Mitsumasa

    2010-04-01

    This study describes the possible separation of chlorinated plastic films (PVC and PVDC) from other heavy plastic packaging waste (PPW) by selective twist formation and gravity separation. Twists formation was mechanically induced in chlorinated plastic films, whereas twist formation did not occur in PS and PET films. After twist formation, all the films had the apparent density of less than 1.0g/cm(3) and floated in water even though the true density was more than 1.0g/cm(3). However, the apparent density of the PS and the PET films increased with agitation to more than 1.0g/cm(3), whereas that of chlorinated plastic films was kept less than 1.0g/cm(3). The main reason would be the air being held inside the chlorinated plastic films which was difficult to be removed by agitation. Simple gravity separation after twist formation was applied for artificial film with 10wt.% of the chlorinated films and real PPW films with 9wt.% of the chlorinated films. About 76wt.% of the artificial PPW films and 75wt.% of real PPW films after the removal of PP and PE were recovered as settling fraction with 4.7wt.% and 3.0wt.% of chlorinated plastic films, respectively. These results indicate that simple gravity separation process after twist formation can be used to reduce the chlorinated plastic concentration from mixed heavy PPW films. Copyright 2009 Elsevier Ltd. All rights reserved.

  13. 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.

  14. Feasibility study of the separation of chlorinated films from plastic packaging wastes

    International Nuclear Information System (INIS)

    Reddy, Mallampati Srinivasa; Yamaguchi, Takefumi; Okuda, Tetsuji; Tsai, Tsung-Yueh; Nakai, Satoshi; Nishijima, Wataru; Okada, Mitsumasa

    2010-01-01

    This study describes the possible separation of chlorinated plastic films (PVC and PVDC) from other heavy plastic packaging waste (PPW) by selective twist formation and gravity separation. Twists formation was mechanically induced in chlorinated plastic films, whereas twist formation did not occur in PS and PET films. After twist formation, all the films had the apparent density of less than 1.0 g/cm 3 and floated in water even though the true density was more than 1.0 g/cm 3 . However, the apparent density of the PS and the PET films increased with agitation to more than 1.0 g/cm 3 , whereas that of chlorinated plastic films was kept less than 1.0 g/cm 3 . The main reason would be the air being held inside the chlorinated plastic films which was difficult to be removed by agitation. Simple gravity separation after twist formation was applied for artificial film with 10 wt.% of the chlorinated films and real PPW films with 9 wt.% of the chlorinated films. About 76 wt.% of the artificial PPW films and 75 wt.% of real PPW films after the removal of PP and PE were recovered as settling fraction with 4.7 wt.% and 3.0 wt.% of chlorinated plastic films, respectively. These results indicate that simple gravity separation process after twist formation can be used to reduce the chlorinated plastic concentration from mixed heavy PPW films.

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

    International Nuclear Information System (INIS)

    Sun Yingxue; Wu Qianyuan; Hu Hongying; Tian Jie

    2009-01-01

    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.

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

    International Nuclear Information System (INIS)

    Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

    2013-01-01

    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 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 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

  17. Acute lung injury and persistent small airway disease in a rabbit model of chlorine inhalation

    Energy Technology Data Exchange (ETDEWEB)

    Musah, Sadiatu; Schlueter, Connie F.; Humphrey, David M. [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States); Powell, Karen S. [Research Resource Facilities, University of Louisville, Louisville, KY (United States); Roberts, Andrew M. [Department of Physiology, University of Louisville, Louisville, KY (United States); Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States)

    2017-01-15

    Chlorine is a pulmonary toxicant to which humans can be exposed through accidents or intentional releases. Acute effects of chlorine inhalation in humans and animal models have been well characterized, but less is known about persistent effects of acute, high-level chlorine exposures. In particular, animal models that reproduce the long-term effects suggested to occur in humans are lacking. Here, we report the development of a rabbit model in which both acute and persistent effects of chlorine inhalation can be assessed. Male New Zealand White rabbits were exposed to chlorine while the lungs were mechanically ventilated. After chlorine exposure, the rabbits were extubated and were allowed to survive for up to 24 h after exposure to 800 ppm chlorine for 4 min to study acute effects or up to 7 days after exposure to 400 ppm for 8 min to study longer term effects. Acute effects observed 6 or 24 h after inhalation of 800 ppm chlorine for 4 min included hypoxemia, pulmonary edema, airway epithelial injury, inflammation, altered baseline lung mechanics, and airway hyperreactivity to inhaled methacholine. Seven days after recovery from inhalation of 400 ppm chlorine for 8 min, rabbits exhibited mild hypoxemia, increased area of pressure–volume loops, and airway hyperreactivity. Lung histology 7 days after chlorine exposure revealed abnormalities in the small airways, including inflammation and sporadic bronchiolitis obliterans lesions. Immunostaining showed a paucity of club and ciliated cells in the epithelium at these sites. These results suggest that small airway disease may be an important component of persistent respiratory abnormalities that occur following acute chlorine exposure. This non-rodent chlorine exposure model should prove useful for studying persistent effects of acute chlorine exposure and for assessing efficacy of countermeasures for chlorine-induced lung injury. - Highlights: • A novel rabbit model of chlorine-induced lung disease was developed.

  18. Chlorine and bromine contents in tobacco and tobacco smoke

    International Nuclear Information System (INIS)

    Haesaenen, E.; Manninen, P.K.G.; Himberg, K.; Vaeaetaeinen, V.

    1990-01-01

    The chlorine and bromine contents in tobacco and tobacco smoke in both the particulate and gaseous phases were studied by neutron activation analysis. Eleven popular brands of western filter cigarettes were tested. Methyl chloride and methyl bromide concentrations were measured in the gaseous phase in two leading brands in Finland. The results suggest that the mainstream smoke from one cigarette conveys into the lungs about 150 μg chlorine and about 5 μg bromine. Probably most of the chlorine and bromine is in the form of organic compounds and the main components are methyl chloride and methyl bromide. (author) 14 refs.; 1 tab

  19. Chromatographic speciation of Cr(III)-species, inter-species equilibrium isotope fractionation and improved chemical purification strategies for high-precision isotope analysis.

    Science.gov (United States)

    Larsen, K K; Wielandt, D; Schiller, M; Bizzarro, M

    2016-04-22

    chromatographic elution strategy that takes advantage of the slow reaction kinetics of de-chlorination of Cr in dilute HCl at room temperature. These procedures significantly improve cation chromatographic purification of Cr over previous methods and allow for high-purity Cr isotope analysis with a total recovery of >95%. Copyright © 2016 Elsevier B.V. All rights reserved.

  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. Structures and Nuclear Quadrupole Coupling Tensors of a Series of Chlorine-Containing Hydrocarbons

    Science.gov (United States)

    Dikkumbura, Asela S.; Webster, Erica R.; Dorris, Rachel E.; Peebles, Rebecca A.; Peebles, Sean A.; Seifert, Nathan A.; Pate, Brooks

    2016-06-01

    Rotational spectra for gauche-1,2-dichloroethane (12DCE), gauche-1-chloro-2-fluoroethane (1C2FE) and both anti- and gauche-2,3-dichloropropene (23DCP) have been observed using chirped-pulse Fourier-transform microwave (FTMW) spectroscopy in the 6-18 GHz region. Although the anti conformers for all three species are predicted to be more stable than the gauche forms, they are nonpolar (12DCE) or nearly nonpolar (predicted dipole components for anti-1C2FE: μ_a = 0.11 D, μ_b = 0.02 D and for anti-23DCP: μ_a = 0.25 D, μ_b = 0.02 D); nevertheless, it was also possible to observe and assign the spectrum of anti-23DCP. Assignments of parent spectra and 37Cl and 13C substituted isotopologues utilized predictions at the MP2/6-311++G(2d,2p) level and Pickett's SPCAT/SPFIT programs. For the weak anti-23DCP spectra, additional measurements also utilized a resonant-cavity FTMW spectrometer. Full chlorine nuclear quadrupole coupling tensors for gauche-12DCE and both anti- and gauche-23DCP have been diagonalized to allow comparison of coupling constants. Kraitchman's equations were used to determine r_s coordinates of isotopically substituted atoms and r_0 structures were also deduced for gauche conformers of 12DCE and 1C2FE. Structural details and chlorine nuclear quadrupole coupling constants of all three molecules will be compared, and effects of differing halogen substitution and carbon chain length on molecular properties will be evaluated.

  2. Degradation of chloramphenicol by UV/chlorine treatment: Kinetics, mechanism and enhanced formation of halonitromethanes.

    Science.gov (United States)

    Dong, Huiyu; Qiang, Zhimin; Hu, Jun; Qu, Jiuhui

    2017-09-15

    Ultraviolet (UV)/chlorine process is considered as an emerging advanced oxidation process for the degradation of micropollutants. This study investigated the degradation of chloramphenicol (CAP) and formation of disinfection by-products (DBPs) during the UV/chlorine treatment. It was found that CAP degradation was enhanced by combined UV/chlorine treatment compared to that of UV and chlorination treatment alone. The pseudo-first-order rate constant of the UV/chlorine process at pH 7.0 reached 0.016 s -1 , which was 10.0 and 2.0 folds that observed from UV and chlorination alone, respectively. The enhancement can be attributed to the formation of diverse radicals (HO and reactive chlorine species (RCSs)), and the contribution of RCSs maintained more stable than that of HO at pH 5.5-8.5. Meanwhile, enhanced DBPs formation during the UV/chlorine treatment was observed. Both the simultaneous formation and 24-h halonitromethanes formation potential (HNMsFP) were positively correlated with the UV/chlorine treatment time. Although the simultaneous trichloronitromethane (TCNM) formation decreased with the prolonged UV irradiation, TCNM dominated the formation of HNMs after 24 h (>97.0%). According to structural analysis of transformation by-products, both the accelerated CAP degradation and enhanced HNMs formation steps were proposed. Overall, the formation of diverse radicals during the UV/chlorine treatment accelerated the degradation of CAP, while also enhanced the formation of DBPs simultaneously, indicating the need for DBPs evaluation before the application of combined UV/chlorine process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Analysis of chest image performance in patients with acute chlorine poisoning

    International Nuclear Information System (INIS)

    Liu Liangqing; Zheng Jiangang; Yang Keyu; Wu Honglin; Tang Qingfang; Wu Huiming

    2012-01-01

    Objective: To explore chest image features of patients with acute chlorine poisoning and their clinical values. Methods: A retrospective analysis was performed by chest image features of 117 patients with acute chlorine poisoning. All the patients were classified according to Chinese management of occupational acute chlorine poisoning diagnosis standard. Results: Sixty-five patients presented with stimulus response, and normal or both lungs had a little more white on their chest images. Thirty-one cases presented with minor poisoning, and without or the texture of both lungs was increased, and grew hazy and coarse.seventeen cases were moderate, and small sample vague shadows or single or multiple limitations lamellar shadow. Four cases were serious,and two lungs had extensive and density homogeneous consolidation shadow. Conclusions: It would make the diagnosis and assessment of chlorine poisoning more easier based on the combination of chest image features, the clear history of acute chlorine poisoning and relevant clinical performance. (authors)

  4. Chlorine-36 investigations of groundwater infiltration in the Exploratory Studies Facility at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Levy, S.S.; Fabryka-Martin, J.T.; Dixon, P.R.; Liu, B.; Turin, H.J.; Wolfsberg, A.V.

    1997-01-01

    Chlorine-36, including the natural cosmogenic component and the component produced during atmospheric nuclear testing in the 1950's and 1960's (bomb pulse), is being used as an isotopic tracer for groundwater infiltration studies at Yucca Mountain, a potential nuclear waste repository. Rock samples have been collected systematically in the Exploratory Studies Facility (ESF), and samples were also collected from fractures, faults, and breccia zones. Isotopic ratios indicative of bomb-pulse components in the water ( 36 Cl/Cl values > 1,250 x 10 -15 ), signifying less than 40-yr travel times from the surface, have been detected at a few locations within the Topopah Spring Tuff, the candidate host rock for the repository. The specific features associated with the high 36 Cl/Cl values are predominantly cooling joints and syngenetic breccias, but most of the sites are in the general vicinity of faults. The non-bomb pulse samples have 36 Cl/Cl values interpreted to indicate groundwater travel times of at least a few thousand to possibly several hundred thousand years. Preliminary numerical solute-travel experiments using the FEHM (Finite Element Heat and Mass transfer) code demonstrate consistency between these interpreted ages and the observed 36 Cl/Cl values but do not validate the interpretations

  5. Inhibition of chlorine-induced lung injury by the type 4 phosphodiesterase inhibitor rolipram

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Weiyuan; Chen, Jing; Schlueter, Connie F. [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States); Rando, Roy J. [Department of Environmental Health Sciences, School of Public Health and Tropical Medicine, Tulane University Health Sciences Center, New Orleans, LA (United States); Pathak, Yashwant V. [College of Pharmacy, University of South Florida, Tampa, FL (United States); Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States)

    2012-09-01

    Chlorine is a highly toxic respiratory irritant that when inhaled causes epithelial cell injury, alveolar-capillary barrier disruption, airway hyperreactivity, inflammation, and pulmonary edema. Chlorine is considered a chemical threat agent, and its release through accidental or intentional means has the potential to result in mass casualties from acute lung injury. The type 4 phosphodiesterase inhibitor rolipram was investigated as a rescue treatment for chlorine-induced lung injury. Rolipram inhibits degradation of the intracellular signaling molecule cyclic AMP. Potential beneficial effects of increased cyclic AMP levels include inhibition of pulmonary edema, inflammation, and airway hyperreactivity. Mice were exposed to chlorine (whole body exposure, 228–270 ppm for 1 h) and were treated with rolipram by intraperitoneal, intranasal, or intramuscular (either aqueous or nanoemulsion formulation) delivery starting 1 h after exposure. Rolipram administered intraperitoneally or intranasally inhibited chlorine-induced pulmonary edema. Minor or no effects were observed on lavage fluid IgM (indicative of plasma protein leakage), KC (Cxcl1, neutrophil chemoattractant), and neutrophils. All routes of administration inhibited chlorine-induced airway hyperreactivity assessed 1 day after exposure. The results of the study suggest that rolipram may be an effective rescue treatment for chlorine-induced lung injury and that both systemic and targeted administration to the respiratory tract were effective routes of delivery. -- Highlights: ► Chlorine causes lung injury when inhaled and is considered a chemical threat agent. ► Rolipram inhibited chlorine-induced pulmonary edema and airway hyperreactivity. ► Post-exposure rolipram treatments by both systemic and local delivery were effective. ► Rolipram shows promise as a rescue treatment for chlorine-induced lung injury.

  6. Role of soot in the transport of chlorine in hydrocarbon-air diffusion flames

    International Nuclear Information System (INIS)

    Venkatesh, S.; Saito, K.; Stencel, J.M.; Majidi, V.; Owens, M.

    1991-01-01

    Soot is an inevitable product of incomplete combustion in many practical combustion systems such as automobiles, incinerators and furnaces. Recent studies on chlorinated hydrocarbon combustion have shown that soot and other praticulates (eg. fly ash) play an important role in secondary reactions leading to the formation of chlorine substituted polyaromatic hydrocarbons (PAHs). In order to attain very high destruction efficiencies the fundamental chemical and physical processes that are associated with combustion, and post-combustion cleanup must be well understood. In order to understand the effect of chlorine on the soot formed in a combustion system, fundamental studies using a coflow laminar hydrocarbon-air diffusion flame have been carried out. Phenomenological studies have revealed the effect of chlorine on the visible structure of the flame. Soot inception activation energies were estimated for methane, ethane and ethylene diffusion flames for the case of with and without chlorine addition. No significant difference in the activation energy was estimated for either case. The effect of chlorine on the soot escape rate of an acetylene diffusion flame was estimated. The soot formed in these diffusion flames was analyzed for chlorine using scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and by laser induced plasma spectroscopy (LIPS). REsults from these techniques indicate the presence of chlorine in the soot formed. In this paper a chemical scheme to explain the chlorine found in the soot is proposed based on known theories of soot formation

  7. 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

  8. Shelf-Life of Chlorine Solutions Recommended in Ebola Virus Disease Response.

    Directory of Open Access Journals (Sweden)

    Qais Iqbal

    Full Text Available In Ebola Virus Disease (EVD outbreaks, it is widely recommended to wash living things (handwashing with 0.05% (500 mg/L chlorine solution and non-living things (surfaces, personal protective equipment, dead bodies with 0.5% (5,000 mg/L chlorine solution. Chlorine solutions used in EVD response are primarily made from powdered calcium hypochlorite (HTH, granular sodium dichloroisocyanurate (NaDCC, and liquid sodium hypochlorite (NaOCl, and have a pH range of 5-11. Chlorine solutions degrade following a reaction highly dependent on, and unusually sensitive to, pH, temperature, and concentration. We determined the shelf-life of 0.05% and 0.5% chlorine solutions used in EVD response, including HTH, NaDCC, stabilized NaOCl, generated NaOCl, and neutralized NaOCl solutions. Solutions were stored for 30 days at 25, 30, and 35°C, and tested daily for chlorine concentration and pH. Maximum shelf-life was defined as days until initial concentration fell to 30 days. Models were developed for solutions with maximum shelf-lives between 1-30 days. Extrapolating to 40°C, the maximum predicted shelf-life for 0.05% and 0.5% NaDCC solutions were 0.38 and 0.82 hours, respectively; predicted shelf-life for 0.05% and 0.5% generated NaOCl solutions were >30 and 5.4 days, respectively. Each chlorine solution type offers advantages and disadvantages to responders, as: NaDCC is an easy-to-import high-concentration effervescent powder; HTH is similar, but forms a precipitate that may clog pipes; and, NaOCl solutions can be made locally, but are difficult to transport. We recommend responders chose the most appropriate source chlorine compound for their use, and ensure solutions are stored at appropriate temperatures and used or replaced before expiring.

  9. A carbon nanotube based resettable sensor for measuring free chlorine in drinking water

    International Nuclear Information System (INIS)

    Hsu, Leo H. H.; Hoque, Enamul; Kruse, Peter; Ravi Selvaganapathy, P.

    2015-01-01

    Free chlorine from dissolved chlorine gas is widely used as a disinfectant for drinking water. The residual chlorine concentration has to be continuously monitored and accurately controlled in a certain range around 0.5–2 mg/l to ensure drinking water safety and quality. However, simple, reliable, and reagent free monitoring devices are currently not available. Here, we present a free chlorine sensor that uses oxidation of a phenyl-capped aniline tetramer (PCAT) to dope single wall carbon nanotubes (SWCNTs) and to change their resistance. The oxidation of PCAT by chlorine switches the PCAT-SWCNT system into a low resistance (p-doped) state which can be detected by probing it with a small voltage. The change in resistance is found to be proportional to the log-scale concentration of the free chlorine in the sample. The p-doping of the PCAT-SWCNT film then can be electrochemically reversed by polarizing it cathodically. This sensor not only shows good sensing response in the whole concentration range of free chlorine in drinking water but is also able to be electrochemically reset back many times without the use of any reagents. This simple sensor is ideally suited for measuring free chlorine in drinking water continuously

  10. Accumulation of chlorinated benzenes in earthworms

    Science.gov (United States)

    Beyer, W.N.

    1996-01-01

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  11. Manganese dioxide nanosheets as an optical probe for photometric determination of free chlorine

    International Nuclear Information System (INIS)

    Yu, Haili; Zheng, Lei

    2016-01-01

    We report on a colorimetric assay for free chlorine using MnO 2 nanosheets as an optical probe. In the absence of free chlorine, the addition of ascorbic acid (AA) causes the chemical dissolution of MnO 2 nanosheets via a redox reaction to result in low absorbance. However, if a solution containing free chlorine is added to the system, AA will be oxidized by free chlorine and the MnO 2 nanosheets will not longer be dissolved. Hence, the AA-induced decoloration will not take place and solution will remain yellow. Under optimized experimental conditions, there is a linear relationship between the change in absorbance at 370 nm and the concentration of free chlorine in the 0.2 to 10 μM concentration range, with an 80 nM detection limit. The detection limit for visual evaluation is 8.0 μM. The assay is fairly selective for free chlorine over common inorganic ions and small organic substances. It was applied to the determination of free chlorine in tap water using the standard addition method. (author)

  12. Ametryn degradation by aqueous chlorine: Kinetics and reaction influences

    International Nuclear Information System (INIS)

    Xu Bin; Gao Naiyun; Cheng Hefa; Hu Chenyan; Xia Shengji; Sun Xiaofeng; Wang Xuejiao; Yang Shaogui

    2009-01-01

    The chemical oxidation of the herbicide ametryn was investigated by aqueous chlorination between pH 4 and 10 at a temperature of 25 deg. C. Ametryn was found to react very rapidly with aqueous chlorine. The reaction kinetics can be well described by a second-order kinetic model. The apparent second-order rate constants are greater than 5 x 10 2 M -1 s -1 under acidic and neutral conditions. The reaction proceeds much more slowly under alkaline conditions. The predominant reactions were found to be the reactions of HOCl with neutral ametryn and the charged ametryn, with rate constants equal to 7.22 x 10 2 and 1.58 x 10 3 M -1 s -1 , respectively. The ametryn degradation rate increases with addition of bromide and decreases with addition of ammonia during the chlorination process. Based on elementary chemical reactions, a kinetic model of ametryn degradation by chlorination in the presence of bromide or ammonia ion was also developed. By employing this model, we estimate that the rate constants for the reactions of HOBr with neutral ametryn and charged ametryn were 9.07 x 10 3 and 3.54 x 10 6 M -1 s -1 , respectively. These values are 10- to 10 3 -fold higher than those of HOCl, suggesting that the presence of bromine species during chlorination could significantly accelerate ametryn degradation.

  13. Chlorination and Carbochlorination of Cerium Oxide

    International Nuclear Information System (INIS)

    Esquivel, Marcelo; Bohe, Ana; Pasquevich, Daniel

    2000-01-01

    The chlorination and carbochlorination of cerium oxide were studied by thermogravimetry under controlled atmosphere (TG) in the 700 0 C 950 0 C temperature range.Both reactants and products were analyzed by X-ray diffraction (RX), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). Thermodynamic calculations were performed by computer assisted software.The chlorination starts at a temperature close to 800 0 C.This reaction involves the simultaneous formation and evaporation of CeCl3.Both processes control the reaction rate and their kinetic may not be easily separated.The apparent chlorination activation energy in the 850 0 C-950 0 C temperature range is 172 to 5 kJ/ mole.Carbon transforms the CeO2-Cl2 into a more reactive system: CeO2-C-Cl2, where the effects of the carbon content, total flow rate and temperature were analyzed.The carbochlorination starting temperature is 700 0 C.This reaction is completed in one step controlled by mass transfer with an apparent activation energy of 56 to 5 kJ/mole in the 850 0 C-950 0 C temperature range

  14. 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

  15. 78 FR 66767 - Chlorinated Isocyanurates From China and Japan

    Science.gov (United States)

    2013-11-06

    ...)] Chlorinated Isocyanurates From China and Japan Determinations On the basis of the record \\1\\ developed in the... reason of imports from China and Japan of chlorinated isocyanurates, provided for in subheadings 2933.69... (LTFV) from Japan and subsidized by the Government of China.\\2\\ \\1\\ The record is defined in sec. 207.2...

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 (t 1/2 = 37.24 min) – accelerator mass spectrometry (AMS) of 36 Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t 1/2 = 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 36 Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for 36 Cl/Cl analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Stephan R., E-mail: srw@tlabs.ac.za [Universität Wien, Fakultät für Physik, Institut für Isotopenforschung und Kernphysik (Austria); Eigl, Rosmarie [Universität Wien, Fakultät für Chemie, Institut für Anorganische Chemie (Austria); Forstner, Oliver; Martschini, Martin; Steier, Peter [Universität Wien, Fakultät für Physik, Institut für Isotopenforschung und Kernphysik (Austria); Sterba, Johannes H. [Technische Universität Wien, Atominstitut (Austria); Golser, Robin [Universität Wien, Fakultät für Physik, Institut für Isotopenforschung und Kernphysik (Austria)

    2015-10-15

    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 (t{sub 1/2} = 37.24 min) – accelerator mass spectrometry (AMS) of {sup 36}Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t{sub 1/2} = 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 {sup 36}Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for {sup 36}Cl/Cl analysis.

  18. 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.

  19. 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

    The release of chlorine (Cl) and sulfur (S) during biomass torrefaction and pyrolysis has been investigated via experiments in two laboratory-scale reactors: a rotating reactor and a fixed bed reactor. Six biomasses with different chemical compositions covering a wide range of ash content and ash...... reporting that biomasses with a lower chlorine content release a higher fraction of chlorine during the pyrolysis process. A significant sulfur release (about 60%) was observed from the six biomasses investigated at 350 degrees C. The initial sulfur content in the biomass did not influence the fraction...

  20. Chlorination of niobium oxide in the presence of carbon monoxide

    International Nuclear Information System (INIS)

    Freitas, L.R. de

    1984-01-01

    The chlorination kinetics of niobium pentoxide in the presence of carbon monoxide between 500-800 0 C of temperature is studied. The following variable that influences on the reaction rate are analysed: gas flow, geometry and volume of the Nb 2 O 5 samples, reaction temperature and composition of the chlorinated mixture. At the same time, two other materials were studied: the CaO.Nb 2 O 5 (synthetized in laboratory) and pyrochlorine concentrates. The three materials are compared for the chlorination method used. (M.A.C.) [pt

  1. Bacterial Community Shift Drives Antibiotic Resistance Promotion during Drinking Water Chlorination.

    Science.gov (United States)

    Jia, Shuyu; Shi, Peng; Hu, Qing; Li, Bing; Zhang, Tong; Zhang, Xu-Xiang

    2015-10-20

    For comprehensive insights into the effects of chlorination, a widely used disinfection technology, on bacterial community and antibiotic resistome in drinking water, this study applied high-throughput sequencing and metagenomic approaches to investigate the changing patterns of antibiotic resistance genes (ARGs) and bacterial community in a drinking water treatment and distribution system. At genus level, chlorination could effectively remove Methylophilus, Methylotenera, Limnobacter, and Polynucleobacter, while increase the relative abundance of Pseudomonas, Acidovorax, Sphingomonas, Pleomonas, and Undibacterium in the drinking water. A total of 151 ARGs within 15 types were detectable in the drinking water, and chlorination evidently increased their total relative abundance while reduced their diversity in the opportunistic bacteria (p < 0.05). Residual chlorine was identified as the key contributing factor driving the bacterial community shift and resistome alteration. As the dominant persistent ARGs in the treatment and distribution system, multidrug resistance genes (mainly encoding resistance-nodulation-cell division transportation system) and bacitracin resistance gene bacA were mainly carried by chlorine-resistant bacteria Pseudomonas and Acidovorax, which mainly contributed to the ARGs abundance increase. The strong correlation between bacterial community shift and antibiotic resistome alteration observed in this study may shed new light on the mechanism behind the chlorination effects on antibiotic resistance.

  2. Water Chlorination for human consumption

    International Nuclear Information System (INIS)

    Innocenti, A.; Giacosa, D.; Segatori, M.

    1999-01-01

    Beginning from this issue, an initiative of Federgasacqua (Federal association dealing with the gas and the water) takes place through the activities of the Task Forces Water Quality Control and Materials and Processes, which aim is to offer to the water industry operators and updated information concerning some main subjects, emphasizing in particular the technical and management applied topics. The paper deals with the chlorination processes in drinking water treatment. An overview of the italian situation is presented, concerning disinfection as well as other oxidation processes, together with an historical background on chlorination. Concerning the applications, the chemical technologies and the main processes, the disinfectant effectiveness and the byproducts formation have been described. Further, the regulations in force have been reported and discussed on national and international bases [it

  3. Microbial chlorination of organic matter in forest soil: investigation using 36Cl-chloride and its methodology.

    Science.gov (United States)

    Rohlenová, J; Gryndler, M; Forczek, S T; Fuksová, K; Handova, V; Matucha, M

    2009-05-15

    Chloride, which comes into the forest ecosystem largely from the sea as aerosol (and has been in the past assumed to be inert), causes chlorination of soil organic matter. Studies of the chlorination showed that the content of organically bound chlorine in temperate forest soils is higher than that of chloride, and various chlorinated compounds are produced. Our study of chlorination of organic matter in the fermentation horizon of forest soil using radioisotope 36Cl and tracer techniques shows that microbial chlorination clearly prevails over abiotic, chlorination of soil organic matter being enzymatically mediated and proportional to chloride content and time. Long-term (>100 days) chlorination leads to more stable chlorinated substances contained in the organic layer of forest soil (overtime; chlorine is bound progressively more firmly in humic acids) and volatile organochlorines are formed. Penetration of chloride into microorganisms can be documented by the freezing/thawing technique. Chloride absorption in microorganisms in soil and in litter residues in the fermentation horizon complicates the analysis of 36Cl-chlorinated soil. The results show that the analytical procedure used should be tested for every soil type under study.

  4. Degradation of Nicotine in Chlorinated Water: Pathways and ...

    Science.gov (United States)

    Report The objective of the study is to illustrate how drinking water would affect alkaloid pesticides, and to address the issue by (a) investigating the fate of nicotine in chlorinated drinking water and deionized water, (b) determining the reaction rate and pathway of the reaction between nicotine and aqueous chlorine, (c) identifying nicotine’s degradation products, and (d) providing data that can be used to assess the potential threat from nicotine in drinking water.

  5. Hazard Assessment on Chlorine Distribution Use of Chemical Transportation Risk Index

    International Nuclear Information System (INIS)

    Kim, Jeong Gon; Byun, Hun Soo

    2014-01-01

    Chlorine is one of the most produced and most used non-flammable chemical substances in the world even though its toxicity and high reactivity cause the ozone layer depletion. However, in modern life, it is impossible to live a good life without using Chlorine and its derivatives since they are being used as an typical ingredient in more than 40 percent of the manufactured goods including medicines, detergents, deodorant, fungicides, herbicides, insecticides, and plastic, etc. Even if Chlorine has been handled and distributed in various business (small and medium-sized businesses, water purification plants, distribution company, etc.), there have been few researches about its possible health hazard and transportation risks. Accordingly, the purpose of this paper is to make a detailed assessment of Chlorinerelated risks and to model an index of chemicals transportation risks that is adequate for domestic circumstances. The assessment of possible health hazard and transportation risks was made on 13 kinds of hazardous chemicals, including liquid chlorine. This research may be contributed to standardizing the risk assessment of Chlorine and other hazardous chemicals by using an index of transportation risks

  6. Hazard Assessment on Chlorine Distribution Use of Chemical Transportation Risk Index

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong Gon [Hanwha Chemical Ulsan Site, Ulsan (Korea, Republic of); Byun, Hun Soo [Chonnam National University, Yeosu (Korea, Republic of)

    2014-12-15

    Chlorine is one of the most produced and most used non-flammable chemical substances in the world even though its toxicity and high reactivity cause the ozone layer depletion. However, in modern life, it is impossible to live a good life without using Chlorine and its derivatives since they are being used as an typical ingredient in more than 40 percent of the manufactured goods including medicines, detergents, deodorant, fungicides, herbicides, insecticides, and plastic, etc. Even if Chlorine has been handled and distributed in various business (small and medium-sized businesses, water purification plants, distribution company, etc.), there have been few researches about its possible health hazard and transportation risks. Accordingly, the purpose of this paper is to make a detailed assessment of Chlorinerelated risks and to model an index of chemicals transportation risks that is adequate for domestic circumstances. The assessment of possible health hazard and transportation risks was made on 13 kinds of hazardous chemicals, including liquid chlorine. This research may be contributed to standardizing the risk assessment of Chlorine and other hazardous chemicals by using an index of transportation risks.

  7. Metabolic fate of chlorinated paraffins

    International Nuclear Information System (INIS)

    Darnerud, P.O.; Biessmann, A.; Brandt, I.

    1982-01-01

    The disposition of three [1- 14 C]-chlorododecanes (MCDD, PCDD I and PCDD II; 17.4%, 55.9%, and 68.5% chlorination) was studied in C57Bl mice. [1- 14 C]-lauric acid (LA) was studied as reference compound. Fifty-two percent (MCDD), 32% (PCDD I), and 8% (PCDD II) of the radioactive doses were exhaled as 14 CO 2 during 12 h after i.v. injection. Similar results were obtained after p.o. administration. In addition to a marked labelling of the liver and fat, the distribution patterns observed at 24 h after administration revealed an uptake of radioactivity in tissues with high cell turnover/high metabolic activity, e.g., intestinal mucosa, bone marrow, salivary glands and thymus. The concentration of radioactivity in these sites and the exhalation of 14 CO 2 , which were inverse to the degree of chlorination, indicate that the chloroalkanes are degraded to metabolites which can be utilized in the intermediary metabolism. A similar, although more pronounced, distribution pattern and 14 CO 2 -exhalation (70% of i.v. dose) was observed after LA administration. The long time retention of heptane-soluble radioactivity in liver and fat (indicating unmetabolized substance) increased with degree of chlorination. On the contrary, the administration of LA and the chlorododecanes MCDD and PCDD I, but not of PCDD II, resulted in a selective labelling of the central nervous system 30-60 days after injection. (orig.)

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

    International Nuclear Information System (INIS)

    Orosco, Pablo; Barbosa, Lucía; Ruiz, María del Carmen

    2014-01-01

    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 2 –N 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 2 O 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 2 atmosphere of the MgO–Al 2 O 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

  9. Spectrographic determination of chlorine and fluorine

    International Nuclear Information System (INIS)

    Contamin, G.

    1965-04-01

    Experimental conditions have been investigated in order to obtain the highest sensitivity in spectrographic determination of chlorine and fluorine using the Fassel method of excitation in an inert atmosphere. The influence of the nature of the atmosphere, of the discharge conditions and of the matrix material has been investigated. The following results have been established: 1. chlorine determination is definitely possible: a working curve has been drawn between 10 μg and 100 μg, the detection limit being around 5 μg; 2. fluorine determination is not satisfactory: the detection limit is still of the order of 80 μg. The best operating conditions have been defined for both elements. (author) [fr

  10. [Chlorine coatings on skin surfaces. II. Parameters influencing the coating strength].

    Science.gov (United States)

    Gottardi, W; Karl, A

    1991-05-01

    Although active chlorine compounds have been used for more than 140 years (Semmelweis, 1848) as a skin disinfectant the phenomenon of the "chlorine covers" not earlier than 1988 has been described for the first time (Hyg. + Med. 13 (1988) 157). It deals with a chemical alteration of the uppermost skin layer which comes apparent in an oxydizing action against aqueous iodide. Its origin is chlorine covalently bound in the form of N-Cl functions to the protein matrix of the horny skin. Since the chlorine covers exhibit a persistant disinfecting activity which might be important for practice, the factors influencing their strength have been established. The most important are: the kind of the chlorine system, the concentration (oxydation capacity), pH, temperature and the volume of the used solution, the time of action, the application technique and the state of the skin. Variations of the latter can be observed at different skin areas of one and the same person as well as at the same areas of different persons, and result in differences of the cover strength up to 100%. The stability on dry skin is very good, showing a decomposition rate of approximately 1.2% per hour. However on skin surfaces moistened by sweat (e.g. hands covered by surgeons gloves) the chlorine cover is disingrated much more faster (decomposition rate: 40-50% per hour). Washing with soap as well as the action of alcohols cause virtually no decrease in the cover strength, while wetting by solutions of reducing agents (e.g. thiosulfate, cysteine, iodide) provokes a fast decomposition suitable for removing the chlorine covers.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Isotopic evidence for identifying the mechanism of salinization of groundwater in Bacolod City,Negros Occidental

    International Nuclear Information System (INIS)

    Castaneda, Soledad S.; Almoneda, Rosalinda V.; Sucgang, Raymond J.; Desengano, Daisy; Lim, Fatima

    2008-01-01

    Saline water is easily identified by measurement of the conductivity of the ionic species in the water. In groundwater, it is important to identify the mechanism of salinization for proper management of the resource. Salinization may come from: a) leaching of salts by percolating water, b) intrusion of modern saltwater bodies of connate water, and c) concentration of dissolved salts due to evaporation. The salinity and isotopic concentrations of 18 O, 2 H, and 3 H of the water sources were used to assess the processes which lead to the salinization of groundwater in Bacolod City, Negros Occidental. The isotopic composition of deep groundwater, river water, and springs cluster along the LMWL with δ 18 O ranging from -7.9 ''promille'' to -6.5 ''promille'' and δ 2 H ranging from -52.6 ''promille'' to -39.1''promille''. Two isotopically distinct groups of deep groundwater were deleated; the higher elevation wells yielding isotopically depleted waters while the lowland wells yielding relatively enriched water with higher conductivity. The shallow coastal wells exhibited more enriched isotope values with δ 18 O values from 6.10 ''promille''-5.61''promille'' and δ 2 H from -43.1''promille'' to -38.8''promille'' and highest conductivity. The relative enrichment in the isotopic composition of the deep groundwater in the lowland and the shallow groundwater along the coast is attributed to saltwater intrusion. The process of salinization in these waters is differentiated based on the relationship between their isotopic compositions and the chlorine concentrations. The high salinity of the isotopically enriched and old deep groundwater inland is attributed to mixing with connate water. On the other hand , mixing with modern sea water is evident in the deep and shallow coastal wells. (author)

  12. Shelf-Life of Chlorine Solutions Recommended in Ebola Virus Disease Response.

    Science.gov (United States)

    Iqbal, Qais; Lubeck-Schricker, Maya; Wells, Emma; Wolfe, Marlene K; Lantagne, Daniele

    2016-01-01

    In Ebola Virus Disease (EVD) outbreaks, it is widely recommended to wash living things (handwashing) with 0.05% (500 mg/L) chlorine solution and non-living things (surfaces, personal protective equipment, dead bodies) with 0.5% (5,000 mg/L) chlorine solution. Chlorine solutions used in EVD response are primarily made from powdered calcium hypochlorite (HTH), granular sodium dichloroisocyanurate (NaDCC), and liquid sodium hypochlorite (NaOCl), and have a pH range of 5-11. Chlorine solutions degrade following a reaction highly dependent on, and unusually sensitive to, pH, temperature, and concentration. We determined the shelf-life of 0.05% and 0.5% chlorine solutions used in EVD response, including HTH, NaDCC, stabilized NaOCl, generated NaOCl, and neutralized NaOCl solutions. Solutions were stored for 30 days at 25, 30, and 35°C, and tested daily for chlorine concentration and pH. Maximum shelf-life was defined as days until initial concentration fell to pH = 7) had a maximum shelf-life of a few hours, NaDCC solutions (pH = 6) 2 days, generated NaOCl solutions (pH = 9) 6 days, and HTH and stabilized NaOCl solutions (pH 9-11) >30 days. Models were developed for solutions with maximum shelf-lives between 1-30 days. Extrapolating to 40°C, the maximum predicted shelf-life for 0.05% and 0.5% NaDCC solutions were 0.38 and 0.82 hours, respectively; predicted shelf-life for 0.05% and 0.5% generated NaOCl solutions were >30 and 5.4 days, respectively. Each chlorine solution type offers advantages and disadvantages to responders, as: NaDCC is an easy-to-import high-concentration effervescent powder; HTH is similar, but forms a precipitate that may clog pipes; and, NaOCl solutions can be made locally, but are difficult to transport. We recommend responders chose the most appropriate source chlorine compound for their use, and ensure solutions are stored at appropriate temperatures and used or replaced before expiring.

  13. 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.

  14. Chlorination of uranium oxides in melts of alkali metal chlorides and their mixtures

    International Nuclear Information System (INIS)

    Vorobej, M.P.; Bevz, A.S.; Skiba, O.V.

    1978-01-01

    Chlorination of UO 2 , U 3 O 8 , and UO 3 in melts of chlorides of alkali metals and of their mixtures has been studied by thermogravimetric, X-ray phase, and spectrophotometric methods. The thermogravimetric method has been proposed for evaluating the state of uranylcation in the melt; the effect of the composition of the oxide being chlorinated and of the salt-solvent on the composition of the chlorination products has been studied. The effect of the composition of the chlorination products on the stoichiometry of the electrolytic uranium dioxide has been shown

  15. Electrochemically activated water as an alternative to chlorine for decentralized disinfection

    KAUST Repository

    Ghebremichael, Kebreab A.; Muchelemba, E.; Petruševski, Branislav; Amy, Gary L.

    2011-01-01

    Electrochemically activated (ECA) water is being extensively studied and considered as an alternative to chlorine for disinfection. Some researchers claim that ECA is by and large a chlorine solution, while others claim the presence of reactive

  16. Normal levels of total body sodium and chlorine by neutron activation analysis

    International Nuclear Information System (INIS)

    Kennedy, N.S.J.; Eastell, R.; Smith, M.A.; Tothill, P.

    1983-01-01

    In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation of normalised sodium was 5.9% in men and 6.9% in women, and of normalised chlorine 9.3% in men and 5.5% in women. In the range examined (40-70 years) no significant age dependence was observed for either element. Total body sodium was correlated with total body chlorine and total body calcium. Sodium excess, defined as the amount of body sodium in excess of that associated with chlorine, also correlated well with total body calcium. In females there was a mean annual loss of sodium excess of 1.2% after the menopause, similar to the loss of calcium. (author)

  17. Chlorin derivatives for potential use in BNCT

    International Nuclear Information System (INIS)

    Osterloh, J.; Neumann, M.; Ruf, S.; Gabel, D.

    2000-01-01

    A series of BSH containing alkyl ether homologues of pytropheophorbide a has been prepared. Cellular uptake studies show that is possible to accumulate 2.2 mg of the heptyl ether after 2 h of incubation with a 0.04 mM solution. That means a boron amount of 330 μg per gram cell mass. Cytotoxicity studies allow radiobiological experiments. The patterns of subcellular localisation visualised by fluorescence microscopy and CLSM show that much of the chlorins is located close to the nucleus and in the nucleus membrane. However, no chlorin was found in the nucleus. (author)

  18. DFT application for chlorin derivatives photosensitizer drugs modeling

    Science.gov (United States)

    Machado, Neila; Carvalho, B. G.; Téllez Soto, C. A.; Martin, A. A.; Favero, P. P.

    2018-04-01

    Photodynamic therapy is an alternative form of cancer treatment that meets the desire for a less aggressive approach to the body. It is based on the interaction between a photosensitizer, activating light, and molecular oxygen. This interaction results in a cascade of reactions that leads to localized cell death. Many studies have been conducted to discover an ideal photosensitizer, which aggregates all the desirable characteristics of a potent cell killer and generates minimal side effects. Using Density Functional Theory (DFT) implemented in the program Vienna Ab-initio Simulation Package, new chlorin derivatives with different functional groups were simulated to evaluate the different absorption wavelengths to permit resonant absorption with the incident laser. Gaussian 09 program was used to determine vibrational wave numbers and Natural Bond Orbitals. The chosen drug with the best characteristics for the photosensitizer was a modified model of the original chlorin, which was called as Thiol chlorin. According to our calculations it is stable and is 19.6% more efficient at optical absorption in 708 nm in comparison to the conventional chlorin e6. Vibrational modes, optical and electronic properties were predicted. In conclusion, this study is an attempt to improve the development of new photosensitizer drugs through computational methods that save time and contribute to decrease the numbers of animals for model application.

  19. Temperature thresholds for chlorine activation and ozone loss in the polar stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Drdla, K. [NASA Ames Research Center, Moffett Field, CA (United States); Mueller, R. [Forschungszentrum Juelich (DE). Inst. of Energy and Climate Research (IEK-7)

    2012-07-01

    Low stratospheric temperatures are known to be responsible for heterogeneous chlorine activation that leads to polar ozone depletion. Here, we discuss the temperature threshold below which substantial chlorine activation occurs. We suggest that the onset of chlorine activation is dominated by reactions on cold binary aerosol particles, without the formation of polar stratospheric clouds (PSCs), i.e. without any significant uptake of HNO{sub 3} from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, T{sub ACL}, is derived. At typical stratospheric conditions, T{sub ACL} is similar in value to T{sub NAT} (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. T{sub NAT} is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause T{sub ACL} to differ from T{sub NAT}: T{sub ACL} is dependent upon H{sub 2} O and potential temperature, but unlike T{sub NAT} is not dependent upon HNO3. Furthermore, in contrast to T{sub NAT}, T{sub ACL} is dependent upon the stratospheric sulfate aerosol loading and thus provides a means to estimate the impact on polar ozone of strong volcanic eruptions and some geo-engineering options, which are discussed. A parameterisation of T{sub ACL} is provided here, allowing it to be calculated for low solar elevation (or high solar zenith angle) over a comprehensive range of stratospheric conditions. Considering T{sub ACL} as a proxy for chlorine activation cannot replace a detailed model calculation, and polar ozone loss is influenced by other factors apart from the initial chlorine activation. However, T{sub ACL} provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than T{sub NAT}. (orig.)

  20. Comparative investigation of X-ray contrast medium degradation by UV/chlorine and UV/H2O2.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Pang, Suyan

    2018-02-01

    The degradation of iopamidol and diatrizoate sodium (DTZ) by UV/chlorine was carried out according to efficiency, mechanism, and oxidation products, and compared to that by UV/H 2 O 2 . The pseudo-first order rate (k') of iopamidol and DTZ was accelerated by UV/chlorine compared to that by UV and chlorine alone. k' of iopamidol and DTZ by UV/chlorine increased with increasing chlorine dosage. Both of iopamidol and DTZ could not be effectively removed by UV/H 2 O 2 compared to that by UV/chlorine. Secondary radicals (Cl 2 - and ClO) rather than primary radicals (HO and Cl) were demonstrated to be mainly responsible for the enhanced removal of iopamidol and DTZ by UV/chlorine. The oxidation products of iopamidol and DTZ resulting from UV/chlorine and UV/H 2 O 2 process were identified, and differences existed in the two systems. IO 3 - (the desired sink of I - ) was the major inorganic product in the UV/chlorine process whereas I - was the predominant inorganic product in the UV/H 2 O 2 process. The formation of chlorine-containing products during the degradation of iopamidol and DTZ by UV/chlorine was also observed. H-abstraction, additions, de-iodination were shared during the degradation of iopamidol by UV/chlorine and UV/H 2 O 2 . Neutral pH condition was preferred for the removal of iopamidol and DTZ by UV/chlorine. UV/chlorine could also be applied in real waters for the removal of iopamidol and DTZ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Short-term toxicity study in rats of chlorinated cake flour.

    Science.gov (United States)

    Fisher, N; Berry, R; Hardy, J

    1983-08-01

    Male and female Wistar rats were fed for 28 days on a diet containing either chlorinated (1257 or 2506 ppm chlorine) or unchlorinated flour. No significant differences between groups in body weight were observed in the males. A significant inverse correlation between body weight and treatment level, attributable to a corresponding trend in food intakes, was found for the females only. No significant differences between absolute organ weights were found, but when the weights were adjusted for covariance with body weight, dose-related increases in kidney weight (males) and liver weight (both sexes) were found. Histopathological examination revealed no pathological tissue changes attributable to the chlorination of the flour.

  2. Natural isotope tracing of hydric transfers in a very low porosity clay-stone formation: the argilites of Tournemire (France)

    International Nuclear Information System (INIS)

    Moreau-Le Golvan, Yann

    1997-01-01

    Since 1988, the experimental site of the French Institute for Protection and Nuclear Safety (IPSN) situated in a tunnel near Toumemire (Aveyron, France), is studied in order to develop techniques and methods for the characterization of water behaviour in a clay-stone formation with very low water content and very low permeability. Isotope geochemistry was used to define the fluid transfer modalities. After the development or the improvement of sampling techniques, the measurement of the stable isotope contents (oxygen-18, deuterium, carbon-13) and radioactive isotope contents (tritium, carbon-14, chlorine-36) of fluids (pore water, fracture water) and solids (calcite fracture fillings) allowed to distinguish several origins and behaviours of water in the massif. The stable isotope distribution of pore water could be due to a diffusion driven mixing between argilite formation water and water from karsts, over and underlying the argilite formation. In this hypothesis, the time needed to establish the distribution profile should be longer than 5 million years. The role of the fractures seems complex, with indications of local paleo-transfers from the matrix to the fracture, and indications of transfers from the karstic aquifer. (author) [fr

  3. Natural isotope tracing of hydric transfers in a very low porosity clay stone formation: the argilites of Tournemire (France)

    International Nuclear Information System (INIS)

    Moreau-Le Golvan, Y.

    1997-01-01

    Since 1988, the experimental site of the French Institute for Protection and Nuclear Safety Safety (IPSN) situated in a tunnel near Tournemire (Aveyron, France), is studied in order to develop techniques and methods for the characterization of water behaviour in a clay-stone formation with very low water content and very low permeability. Isotope geochemistry was used to define the fluid transfer modalities. After the development development of the improvement of sampling techniques, the measurement of the stable isotope contents (oxygen - 18, deuterium, carbon-13) and radioactive isotope contents (tritium, carbon-14, chlorine-36) of fluids (pore water, fracture water) and solids (calcite fracture fillings) allowed to distinguish several origins and behaviours of water in the massif. The stable isotope distribution of pore water could be due to a diffusion driven mixing between argillite formation water and water from karsts, over and underlying the argillite formation. In this hypothesis, the time needed to establish the distribution profile should be longer than 5 million years. The role of the fractures seems complex, with indications of local paleo-transfers from the matrix to the fracture, and indications of transfers from the karstic aquifer. (author)

  4. Bio-remediation of aquifers polluted by chlorinated solvents

    International Nuclear Information System (INIS)

    Fayolle, F.

    1996-01-01

    Numerous cases of contamination of aquifers by chlorinated aliphatic solvents, largely utilized during the last decades, constitute a public health problem, because of the toxic effect of such compounds. Different types of aerobic or anaerobic bacteria are able to degrade these molecules. Processes of bio remediation are now experimented in order to restore polluted aquifers. We present here the microorganisms and the enzymatic reactions involved in the biodegradation of chlorinated solvents, and different examples of in situ bio remediation operations are described. (author)

  5. Formation of emerging DBPs from the chlorination and chloramination of seawater algal organic matter and related model compounds

    KAUST Repository

    Nihemaiti, Maolida

    2014-05-01

    Limited studies focused on reactions occurring during disinfection and oxidation processes of seawater. The aim of this work was to investigate disinfection by-products (DBPs) formation from the chlorination and chloramination of seawater algal organic matter and related model compounds. Simulated algal blooms directly growing in Red Sea, red tide samples collected during an algal bloom event and Hymenomonas sp. monoculture were studied as algal organic matter sources. Experiments were conducted in synthetic seawater containing bromide ion. A variety of DBPs was formed from the chlorination and chloramination of algal organic matter. Brominated DBPs (bromoform, DBAA, DBAN and DBAcAm) were the dominant species. Iodinated DBPs (CIAcAm and iodinated THMs) were detected, which are known to be highly toxic compared to their chlorinated or brominated analogues. Algal organic matter was found to incorporate important precursors of nitrogenous DBPs (N-DBPs), which have been reported to be more toxic than regulated THMs and HAAs. Isotopically-labeled monochloramine (15N- NH2Cl) was used in order to investigate the nitrogen source in N-DBPs. High formation of N-DBPs was found from Hymenomonas sp. sample in exponential growth phase, which was enriched in nitrogen-containing organic compounds. High inorganic nitrogen incorporation was found from the algal samples enriched in humic-like compounds. HAcAms formation was studied from chlorination and chloramination of amino acids. Asparagine, aspartic acid and other amino acids with an aromatic structure were found to be important precursors of HAcAms and DCAN. Factors affecting HAcAms formation (Cl2/ amino acid molar ratio and pH) were evaluated. Studies on the formation kinetics of DCAcAm and DCAN from asparagine suggested a rapid formation of DCAcAm from organic nitrogen (amide group) and a slower incorporation of inorganic nitrogen coming from monochloramine to form DCAN. High amounts of DCAN and DCAcAm were detected from the

  6. Efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate Escherichia coli O157:H7 from lettuce leaves.

    Science.gov (United States)

    Keskinen, Lindsey A; Burke, Angela; Annous, Bassam A

    2009-06-30

    This study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, pH 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, Sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, TriNova) washes in reducing populations of Escherichia coli O157:H7 on artificially inoculated lettuce. Fresh-cut leaves of Romaine or Iceberg lettuce were inoculated by immersion in water containing E. coli O157:H7 (8 log CFU/ml) for 5 min and dried in a salad spinner. Leaves (25 g) were then washed for 2 min, immediately or following 24 h of storage at 4 degrees C. The washing treatments containing chlorite ion concentrations of 100 and 200 ppm were the most effective against E. coli O157:H7 populations on Iceberg lettuce, with log reductions as high as 1.25 log CFU/g and 1.05 log CFU/g for TriNova and Sanova wash treatments, respectively. All other wash treatments resulted in population reductions of less than 1 log CFU/g. Chlorine (200 ppm), TriNova, Sanova, and acidic electrolyzed water were all equally effective against E. coli O157:H7 on Romaine, with log reductions of approximately 1 log CFU/g. The 20 ppm chlorine wash was as effective as the deionized water wash in reducing populations of E. coli O157:H7 on Romaine and Iceberg lettuce. Scanning electron microscopy indicated that E. coli O157:H7 that was incorporated into biofilms or located in damage lettuce tissue remained on the lettuce leaf, while individual cells on undamaged leaf surfaces were more likely to be washed away.

  7. Metagenomic insights into chlorination effects on microbial antibiotic resistance in drinking water.

    Science.gov (United States)

    Shi, Peng; Jia, Shuyu; Zhang, Xu-Xiang; Zhang, Tong; Cheng, Shupei; Li, Aimin

    2013-01-01

    This study aimed to investigate the chlorination effects on microbial antibiotic resistance in a drinking water treatment plant. Biochemical identification, 16S rRNA gene cloning and metagenomic analysis consistently indicated that Proteobacteria were the main antibiotic resistant bacteria (ARB) dominating in the drinking water and chlorine disinfection greatly affected microbial community structure. After chlorination, higher proportion of the surviving bacteria was resistant to chloramphenicol, trimethoprim and cephalothin. Quantitative real-time PCRs revealed that sulI had the highest abundance among the antibiotic resistance genes (ARGs) detected in the drinking water, followed by tetA and tetG. Chlorination caused enrichment of ampC, aphA2, bla(TEM-1), tetA, tetG, ermA and ermB, but sulI was considerably removed (p water chlorination could concentrate various ARGs, as well as of plasmids, insertion sequences and integrons involved in horizontal transfer of the ARGs. Water pipeline transportation tended to reduce the abundance of most ARGs, but various ARB and ARGs were still present in the tap water, which deserves more public health concerns. The results highlighted prevalence of ARB and ARGs in chlorinated drinking water and this study might be technologically useful for detecting the ARGs in water environments. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Chlorination of uranium oxides with CCl{sub 4} using a mechanochemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kitawaki, Shinichi, E-mail: kitawaki.shinichi@jaea.go.jp [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai, Naka, Ibaraki 319-1194 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577 (Japan); Nagai, Takayuki [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33 Muramatsu, Tokai, Naka, Ibaraki 319-1194 (Japan); Sato, Nobuaki [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577 (Japan)

    2013-08-15

    Highlights: • UCl{sub 4} or UOCl{sub 2} could be synthesized from U{sub 3}O{sub 8} with CCl{sub 4} by using a planetary ball mill. • The chlorination could not be observed when using UO{sub 2} powder as the starting material. • Extension of milling time was effective for chlorinating U{sub 3}O{sub 8} with the appropriate amount of CCl{sub 4}. -- Abstract: A chlorination method for uranium oxides at low temperature was investigated by using a mechanochemical method. In particular, the possibility of the chlorination of uranium oxides, such as UO{sub 2} and U{sub 3}O{sub 8}, via mechanochemical reaction with CCl{sub 4} was studied using a planetary ball mill. Mechanochemical experiments were conducted to evaluate the effect of milling time, CCl{sub 4}/uranium oxide molar ratio, and revolution speed on the reaction. The synthesized products were then subjected to X-ray diffraction analysis, and it was found that the chlorination of U{sub 3}O{sub 8} with CCl{sub 4} to UOCl{sub 2}, UCl{sub 4}, and U{sub 2}O{sub 2}Cl{sub 5} proceeded. However, the chlorination reaction could not be observed when using UO{sub 2} powder as the raw material.

  9. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. 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%. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. 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.

  12. 2.2. Chlorination of pre-baked danburite with reducer

    International Nuclear Information System (INIS)

    Mirsaidov, U.; Mamatov, E.D.; Safiev, Kh.S.

    2013-01-01

    According to conducted studied it was found that increasing of reactivity of danburite rock with gaseous chlorine after heat treatment connected with danburite decomposition: Ca O·B 2 O 3 ·2SiO 2 →Ca O·B 2 O 3 +2SiO 2 . The dependence of extraction rate of boron oxide on temperature, process duration, reducer (coal) and size of particles of danburite rock is defined. By means of X-ray analysis method the composition of danburite rock before and after pre-baking was defined as well. The impact of pre-baking on danburite chlorination was studied at 400-800 deg C during 60 minutes with reducer. The optimal parameters for chlorination of burned danburite are: temperature - 700 deg C, process duration - 120 minutes, and reducer containing - 30%.

  13. 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.

  14. 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

  15. Kinetics of membrane damage to high (HNA) and low (LNA) nucleic acid bacterial clusters in drinking water by ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate.

    Science.gov (United States)

    Ramseier, Maaike K; von Gunten, Urs; Freihofer, Pietro; Hammes, Frederik

    2011-01-01

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of membrane damage of native drinking water bacterial cells. Membrane damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the membrane damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell membranes of high nucleic acid (HNA) content bacteria were damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell membranes have a different chemical constitution. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Application of activated carbons from coal and coconut shell for removing free residual chlorine.

    Science.gov (United States)

    Ogata, Fumihiko; Tominaga, Hisato; Ueda, Ayaka; Tanaka, Yuko; Iwata, Yuka; Kawasaki, Naohito

    2013-01-01

    This study investigated the removal of free residual chlorine by activated carbon (AC). ACs were prepared from coal (AC1) and coconut shell (AC2). The specific surface area of AC1 was larger than that of AC2. The removal of free residual chlorine increased with elapsed time and amount of adsorbent. The removal mechanism of free residual chlorine was the dechlorination reaction between hypochlorous acid or hypochlorite ion and AC. Moreover, AC1 was useful in the removal of free residual chlorine in tap water. The optimum condition for the removal of free residual chlorine using a column is space velocity 306 1/h; liner velocity 6.1 m/h.

  17. Preparing of LiCl-KCl-UCl3 eutectic salt by a chlorination of Cd

    International Nuclear Information System (INIS)

    Kang, Hee Seok; Woo, Moon Sik; Lee, Han Soo

    2008-01-01

    Uranium trichloride salt(UCl 3 ) is supplied with the initial U in to the LiCl-KCl eutectic salt for a stabilization of the initial cell voltage during an electrorefining process in a reactor. The apparatus for producing UCl 3 consists of a chlorine gas generator, a chlorinator, and an off-gas wet scrubber. Gaseous chlorine in the chlorine gas generator was injected into a lower layer of liquid Cd where CdCl 2 formed. The CdCl 2 reacts with the uranium to form uranium trichloride and Cd. The throughput of the UCl 3 chlorinator is about. 1.4Kg UCl 3 /batch. During a production the temperature of the reactants are maintained at about 600 .deg. C

  18. Biogeochemial modeling of biodegradation and stable isotope fractionation of DCE in a small-scale wetland

    Science.gov (United States)

    Alvarez-Zaldívar, Pablo; Imfeld, Gwenaël; Maier, Uli; Centler, Florian; Thullner, Martin

    2013-04-01

    In recent years, the use of (constructed) wetlands has gained significant attention for the in situ remediation of groundwater contaminated with (chlorinated) organic hydrocarbons. Although many sophisticated experimental methods exist for the assessment of contaminant removal in such wetlands the understanding how changes in wetland hydrochemistry affect the removal processes is still limited. This knowledge gap might be reduced by the use of biogeochemical reactive transport models. This study presents the reactive transport simulation of a small-scale constructed wetland treated with groundwater containing cis-1,2-dichloroethene (cDCE). Simulated processes consider different cDCE biodegradation pathways and the associated carbon isotope fractionation, a set of further (bio)geochemical processes as well as the activity of the plant roots. Spatio-temporal hydrochemical and isotope data from a long-term constructed wetland experiment [1] are used to constrain the model. Simulation results for the initial oxic phase of the wetland experiment indicate carbon isotope enrichment factors typical for cometabolic DCE oxidation, which suggests that aerobic treatment of cDCE is not an optimal remediation strategy. For the later anoxic phase of the experiment model derived enrichment factors indicate reductive dechlorination pathways. This degradation is promoted at all wetland depths by a sufficient availability of electron donor and carbon sources from root exudates, which makes the anoxic treatment of groundwater in such wetlands an effective remediation strategy. In combination with the previous experimental data results from this study suggest that constructed wetlands are viable remediation means for the treatment of cDCE contaminated groundwater. Reactive transport models can improve the understanding of the factors controlling chlorinated ethenes removal, and the used model approach would also allow for an optimization of the wetland operation needed for a complete

  19. Stable isotope analyses of oxygen (18O:17O:16O) and chlorine (37Cl:35Cl) in perchlorate: reference materials, calibrations, methods, and interferences

    Science.gov (United States)

    Böhlke, John Karl; Mroczkowski, Stanley J.; Sturchio, Neil C.; Heraty, Linnea J.; Richman, Kent W.; Sullivan, Donald B.; Griffith, Kris N.; Gu, Baohua; Hatzinger, Paul B.

    2017-01-01

    RationalePerchlorate (ClO4−) is a common trace constituent of water, soils, and plants; it has both natural and synthetic sources and is subject to biodegradation. The stable isotope ratios of Cl and O provide three independent quantities for ClO4− source attribution and natural attenuation studies: δ37Cl, δ18O, and δ17O (or Δ17O or 17Δ) values. Documented reference materials, calibration schemes, methods, and interferences will improve the reliability of such studies.MethodsThree large batches of KClO4 with contrasting isotopic compositions were synthesized and analyzed against VSMOW-SLAP, atmospheric O2, and international nitrate and chloride reference materials. Three analytical methods were tested for O isotopes: conversion of ClO4− to CO for continuous-flow IRMS (CO-CFIRMS), decomposition to O2 for dual-inlet IRMS (O2-DIIRMS), and decomposition to O2 with molecular-sieve trap (O2-DIIRMS+T). For Cl isotopes, KCl produced by thermal decomposition of KClO4 was reprecipitated as AgCl and converted into CH3Cl for DIIRMS.ResultsKClO4 isotopic reference materials (USGS37, USGS38, USGS39) represent a wide range of Cl and O isotopic compositions, including non-mass-dependent O isotopic variation. Isotopic fractionation and exchange can affect O isotope analyses of ClO4− depending on the decomposition method. Routine analyses can be adjusted for such effects by normalization, using reference materials prepared and analyzed as samples. Analytical errors caused by SO42−, NO3−, ReO42−, and C-bearing contaminants include isotope mixing and fractionation effects on CO and O2, plus direct interference from CO2 in the mass spectrometer. The results highlight the importance of effective purification of ClO4− from environmental samples.ConclusionsKClO4 reference materials are available for testing methods and calibrating isotopic data for ClO4− and other substances with widely varying Cl or O isotopic compositions. Current ClO4−extraction, purification

  20. Reaction kinetics and transformation of carbadox and structurally related compounds with aqueous chlorine.

    Science.gov (United States)

    Shah, Amisha D; Kim, Jae-Hong; Huang, Ching-Hua

    2006-12-01

    The potential release of carbadox (CDX), a commonly used antibacterial agent in swine husbandry, into water systems is of a concern due to its carcinogenic and genotoxic effects. Until this study, the reactivity of carbadox (possessing quinoxaline N,N'-dioxide and hydrazone moieties) toward aqueous chlorine has yetto be investigated in depth. Chemical reactivity, reaction kinetics, and transformation pathways of carbadox and structurally related compounds with free chlorine under typical water treatment conditions were determined. This study found that only CDX and desoxycarbadox (DCDX), a main metabolite of CDX with no ring N-oxide groups, react rapidly with free chlorine while other structurally related compounds including olaquindox, quindoxin, quinoxaline N-oxide, quinoxaline, and quinoline N-oxide do not. The reaction kinetics of CDX and DCDX with chlorine are highly pH dependent (e.g., the apparent second-order rate constant, kapp, for CDX ranges from 51.8 to 3.15 x 10(4) M(-1)s(-1) at pH 4-11). The high reactivity of CDX and DCDX to chlorine involves deprotonation of their hydrazone N-H moieties where initial chlorine attack results in a reactive intermediate that is further attacked by nucleophiles in the matrix to yield non-chlorinated, hydroxylated, and larger molecular weight byproducts. All of the CDX's byproducts retain their biologically active N-oxide groups, suggesting that they may remain as active antibacterial agents.

  1. Inactivation of Giardia muris cysts by free chlorine.

    OpenAIRE

    Leahy, J G; Rubin, A J; Sproul, O J

    1987-01-01

    The chlorine resistance of cysts of the flagellate protozoan Giardia muris was examined. This organism, which is pathogenic to mice, is being considered as a model for the inactivation of the human pathogen Giardia lamblia. Excystation was used as the criterion for cyst viability. Experiments were performed at pH 5, 7, and 9 at 25 degrees C and pH 7 at 5 degrees C. Survival curves were "stepladder"-shaped, but concentration-time data generally conformed to Watson's Law. Chlorine was most effe...

  2. Combined treatment of Pseudomonas aeruginosa biofilms with bacteriophages and chlorine.

    Science.gov (United States)

    Zhang, Yanyan; Hu, Zhiqiang

    2013-01-01

    Bacterial biofilms are a growing concern in a broad range of areas. In this study, a mixture of RNA bacteriophages isolated from municipal wastewater was used to control and remove biofilms. At the concentrations of 400 and 4 × 10(7) PFU/mL, the phages inhibited Pseudomonas aeruginosa biofilm formation by 45 ± 15% and 73 ± 8%, respectively. At the concentrations of 6,000 and 6 × 10(7) PFU/mL, the phages removed 45 ± 9% and 75 ± 5% of pre-existing P. aeruginosa biofilms, respectively. Chlorine reduced biofilm growth by 86 ± 3% at the concentration of 210 mg/L, but it did not remove pre-existing biofilms. However, a combination of phages (3 × 10(7) PFU/mL) and chlorine at this concentration reduced biofilm growth by 94 ± 2% and removed 88 ± 6% of existing biofilms. In a continuous flow system with continued biofilm growth, a combination of phages (a one-time treatment at the concentration of 1.9 × 10(8) PFU/mL for 1 h first) with chlorine removed 97 ± 1% of biofilms after Day 5 while phage and chlorine treatment alone removed 89 ± 1% and 40 ± 5%, respectively. For existing biofilms, a combined use of a lower phage concentration (3.8 × 10(5) PFU/mL) and chlorination with a shorter time duration (12 h) followed by continuous water flushing removed 96 ± 1% of biofilms in less than 2 days. Laser scanning confocal microscopy supplemented with electron microscopy indicated that the combination treatment resulted in biofilms with lowest cell density and viability. These results suggest that the combination treatment of phages and chlorine is a promising method to control and remove bacterial biofilms from various surfaces. Copyright © 2012 Wiley Periodicals, Inc.

  3. Determination of water movement in the unsaturated zone at Yucca Mountain using chloride, bromide, and chlorine isotopes as environmental tracers. Final report

    International Nuclear Information System (INIS)

    1994-01-01

    This report, prepared by Hydro Geo Chem staff for Los Alamos National Laboratory, summarizes work conducted by the company under Subcontract 9-XG1-N3993-1. The ultimate objective of this work is to characterize the movement of subsurface water in the vicinity of Yucca Mountain, Nevada. Data produced under this contract is to be used by the US Department of Energy in its Yucca Mountain Site Characterization Project (YMP) to help determine hydrologic flows that may affect the performance of a potential nuclear waste repository. The data may be used in the licensing proceedings, and certain quality assurance procedures have thus been required. The work has focussed on measuring the distribution of environmental tracers-chlorine-36, chlorine, and bromine-and on evaluating the depth to which these conservative solutes have percolated in the unsaturated zone at Yucca Mountain. The following discussion summarizes progress made on the tasks outlined in the original Scope of Work. Details of this work and all data acquired by Hydro Geo Chem for this subcontract have been systematically organized in logbooks and laboratory notebooks. These documents have been structured to make it easy to trace the analytical history of a sample, from time of receipt to the final analytical results

  4. Removal of chlorinated organic compounds from gas phase using electron beam technology

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.; Bulka, S.; Zimek, A. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Chmielewski, A. G. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland); Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw (Poland)

    2011-07-01

    Selected chlorinated organic compounds (Cl-HC), which are emitted from coal fired power plants, waste incinerators, chemical industry etc., are very harmful to the environment and human’s health. Some of them are listed as carcinogenic compounds by USA EPA. Recent studies show that some chlorinated organic compounds are suspected to be precursors for dioxins formation. Chlorinated organic compounds decomposition in air in an electron beam (EB) generated plasma reactor technology was studied. We selected cis-dichloroethylene (cis-DCE), 1,4-dichlorobenznene(1,4-DCB), 1-chloronaphthalene as studied objects. It is found that chlorinated organic compounds can be decomposed in an electron beam generated plasma reactor. The order of decomposition efficiency of these compounds are: cis-DCE > 1,4-DCB> 1-chloronaphthalene. (author)

  5. Chlorine attack in copper/cupronickel heat exchangers tubes in service water system

    International Nuclear Information System (INIS)

    Hortiguela, Ruben; Corchon, Fernando; Villesccas, Gilberto

    2012-09-01

    Santa Maria de Garona is a nuclear power plant design BWR type 3 with an open cooling circuit without cooling towers which outlets to the Ebro river. In November 2006, the presence of zebra mussels was found upstream of the plant intake. The recommended option for the service water system was to install a chlorination treatment using liquid sodium hypochlorite. This recommendation was based primarily on the need to have an effective mitigation system in place at Garona in the summer of 2007. The recommendation was to apply continuous or semi-continuous addition of chlorine to the service water system, preventing any primary attachment of zebra mussels to the service water piping. The chlorine injection system was designed to deliver approximately 0,3 to 0,5 ppm Total Residual Chlorine (TRC) to the service water on continuous basis. The chlorine injection pumps located at the start of the service water system are controlled by the output of a chlorine analyzer located at the end of the service water system just prior to discharge. After four years injecting NaClO, numerous cases of tube failures in heat exchangers made of copper and cupronickel alloys have been detected. The reactions involved are as follows: Corrosion Reactions in Cupronickel alloys Cl 2 + Ni → NiCl 2 E=1.610 V (Pitting Initiator), Cl 2 + Cu → CuCl 2 E=1.023 V. Corrosion Reactions in Copper tubes Cl 2 + Cu → CuCl 2 E=1.023 V. A close examination by optical microscope of the internal wall of the tubes has shown the typical crystals created from chorine corrosion such as: Cu (OH) 2 , CuCl 2 . (2H 2 O),NiCl 2 , [CuCl 3 ] -1 and [CuCl 4 ] -2 Conclusions: The degradation of the material is due to a combination of the following items: - Ageing of material after many years of operation; - Erosion due to poor quality of river water (silica particles, silts, sediments, etc); - Attack from chlorination to base material; The solutions that have been implemented are mainly: - Reduction of chlorine

  6. Hydrogen/Chlorine exchange reactions of gaseous carbanions.

    Science.gov (United States)

    Chen, Hao; Cooks, R Graham; Meurer, Eduardo C; Eberlin, Marcos N

    2005-12-01

    Gas-phase reactions of three typical carbanions CH(2)NO(2)(-), CH(2)CN(-), and CH(2)S(O)CH(3)(-) with the chloromethanes CH(2)Cl(2), CHCl(3), and CCl(4), examined by tandem mass spectrometry, show a novel hydrogen/chlorine exchange reaction. For example, reaction between the nitromethyl anion CH(2)NO(2)(-) and carbon tetrachloride CCl(4) forms the ion CHClNO(2)(-). The suggested reaction mechanism involves nucleophilic attack by CH(2)NO(2)(-) at the chlorine of CCl(4) followed by proton transfer within the resulting complex [CH(2)ClNO(2) + CCl(3)(-)] to form CHClNO(2)(-) and CHCl(3). Two other carbanions CH(2)CN(-) and CH(2)S(O)CH(3)(-) also undergo the novel hydrogen/chlorine exchange reactions with CCl(4) but to a much smaller extent, their higher nucleophilicities favoring competitive nucleophilic attack reactions. Proton abstraction is the exclusive pathway in the reactions of these carbanions with CHCl(3). While CH(2)CN(-) and CH(2)S(O)CH(3)(-) promote mainly proton abstraction and nucleophilic displacement in reactions with CH(2)Cl(2), CH(2)NO(2)(-) does not react.

  7. Radiolytic degradation of chlorinated hydrocarbons in water

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xing-Zheng; Yamamoto, Takeshi [Fukui Univ., Faculty of Engineering, Dept. of Materials Science and Engineering, Fukui (Japan); Hatashita, Masanori [The Wakasa Wan Energy Research Center, Research Dept., Tsuruga, Fukui (Japan)

    2002-11-01

    Radiolytic degradation of chlorinated hydrocarbons (chloroform, trichloroethylene, and tetrachloroethylene) in water was carried out. Water solutions of the chlorinated hydrocarbons with different concentrations were irradiated with {gamma} rays. Concentrations of methane, ethane, CO, CO{sub 2}, H{sub 2}, and O{sub 2} after the irradiation were determined by gas chromatography. Concentration of chloride ion in the irradiated sample was determined by ion chromatography. Experimental results show that radiolytic degradation of the chlorinated hydrocarbon increased with the radiation dose. Methane, ethane, CO{sub 2}, H{sub 2}, and Cl{sup -} concentrations increased with the radiation dose and the sample concentration. On the other hand, O{sub 2} concentration decreased with the radiation dose and the sample concentration. When sample concentration was high, dissolved oxygen might be not enough for converting most of the C atoms in the sample into CO{sub 2}. This resulted in a low decomposition ratio. Addition of H{sub 2}O{sub 2} as an oxygen resource could increase the decomposition ratio greatly. Furthermore, gas chromatography-mass spectroscopy was applied to identify some intermediates of the radiolytic dehalogenation. Radiolytic degradation mechanisms are also discussed. (author)

  8. Analysis of alternative flow sheets for the hybrid chlorine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Gooding, Charles H. [Department of Chemical and Biomolecular Engineering, 209 Earle Hall, Clemson University, Clemson, SC 29634-0909 (United States)

    2009-05-15

    This paper reports the results of the most complete conceptual study conducted to date on hydrogen production using the hybrid chlorine cycle. Three alternative process flow sheets were developed, each capable of producing hydrogen at 35 C (308 K) and 21 bar. The alternative approaches differ primarily in the way HCl is isolated and converted to hydrogen and chlorine gases. Aspen Plus trademark simulation software was used to model the unit processes, supplemented where necessary by custom Excel spreadsheets. Major equipment was sized for a 200-million kg/yr plant; feasible materials of construction were identified; fixed capital investments and variable costs were estimated. Estimated net thermal efficiencies of the flow sheets range from 30% to 36%, based on the lower heating value of the hydrogen produced. With electrical power valued at $0.05/kWh, the cost of hydrogen produced by the hybrid chlorine cycle would be at least $3/kg. These results indicate that direct electrolysis of water is a more attractive way to produce hydrogen than any presently conceived version of the hybrid chlorine cycle. (author)

  9. 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...

  10. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Novak, Spencer; Richardson, Kathleen [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Materials Science and Engineering, COMSET, Clemson University, Clemson, South Carolina 29634 (United States); Fathpour, Sasan, E-mail: fathpour@creol.ucf.edu [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States)

    2015-03-16

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes.

  11. Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

    International Nuclear Information System (INIS)

    Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh; Novak, Spencer; Richardson, Kathleen; Fathpour, Sasan

    2015-01-01

    A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes

  12. Study of the production of Zirconium tetracheoride by chlorination of its oxide

    International Nuclear Information System (INIS)

    Seo, E.S.M.; Abrao, A.

    1987-08-01

    This work describes the studies carried out on the production of zirconium tetrachloride by chlorianation of pure zirconium oxide with (a) carbon tetrachloride and (b) chlorine in the presence of carbon. In the process of chlorination with carbon tetrachloride it has been determined that efficiency increases with the rising of temperature between 450 and 750 0 C. The flow rate of the carbon tetrachloride vapour used was 1.50L/min. For the zirconium oxide chlorination in the presence of carbon, the study has been carried out at temperatures between 700 and 850 0 C and the flow rate of the chlorine gas used in the process was 0,50/Lmin. Pure zirconium oxide chlorination as well as zirconium oxide-carbon mixture chlrorination have been studied in connection with the time of reaction at different temperatures and the apparent rate constants, the activation energies, the order of reaction in relation to the concentration of the gases (CCl 4 and Cl 2 ) and the content of carbon in the pellet have all been determined. (Author) [pt

  13. UV/chlorine treatment of carbamazepine: Transformation products and their formation kinetics.

    Science.gov (United States)

    Pan, Yanheng; Cheng, ShuangShuang; Yang, Xin; Ren, Jingyue; Fang, Jingyun; Shang, Chii; Song, Weihua; Lian, Lushi; Zhang, Xinran

    2017-06-01

    Carbamazepine (CBZ) is one of the pharmaceuticals most frequently detected in the aqueous environment. This study investigated the transformation products when CBZ is degraded by chlorine under ultraviolet (UV) irradiation (the UV/chlorine process). Detailed pathways for the degradation of CBZ were elucidated using ultra-high performance liquid chromatography (UHPLC)-quadrupole time-of-flight mass spectrometry (QTOF-MS). CBZ is readily degraded by hydroxyl radicals (HO) and chlorine radicals (Cl) in the UV/chlorine process, and 24 transformation products were identified. The products indicate that the 10,11-double bond and aromatic ring in CBZ are the sites most susceptible to attack by HO and Cl. Subsequent reaction produces hydroxylated and chlorinated aromatic ring products. Four specific products were quantified and their evolution was related with the chlorine dose, pH, and natural organic matter concentration. Their yields showed an increase followed by a decreasing trend with prolonged reaction time. CBZ-10,11-epoxide (I), the main quantified transformation product from HO oxidation, was observed with a peak transformation yield of 3-32% depending on the conditions. The more toxic acridine (IV) was formed involving both HO and Cl with peak transformation yields of 0.4-1%. All four quantified products together amounted to a peak transformation yield of 34.5%. The potential toxicity of the transformation products was assayed by evaluating their inhibition of the bioluminescence of the bacterium Vibrio Fischeri. The inhibition increased at first and the decreased at longer reaction times, which was in parallel with the evolution of transformation products. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Chlorine Dioxide: The State of Science, Regulatory, Environmental Issues, and Case Histories

    National Research Council Canada - National Science Library

    Burton, Dennis

    2001-01-01

    The use of chlorine by electric utilities and other surface water users to inhibit biofouling and the chlorination of wastewater by POTWs to eliminate the discharge of pathogenic organisms are widespread practices...

  15. Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

    Science.gov (United States)

    Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

    1995-01-01

    Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus. PMID:7793931

  16. Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

    Science.gov (United States)

    Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

    1995-06-01

    Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

  17. Dealing with the chlorinated solvent situation at the Oak Ridge Y-12 Plant

    International Nuclear Information System (INIS)

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

    1993-01-01

    Recent events regarding health and environmental problems associated with the use of chlorinated solvents have prompted the Oak Ridge Y-12 Plant to investigate substitutes for these materials. Since 1987, the purchase of chlorinated solvents at the Y-12 Plant has been reduced by 92%. This has been accomplished by substituting chlorinated solvent degreasing with ultrasonic aqueous detergent cleaning and by substituting chlorinated solvents with less toxic, environmentally friendly solvents for hand-wiping applications. Extensive studies of cleaning ability, compabitility, and effects on welding, bonding, and painting have been conducted to gain approval for use of these solvents. Toxicity and waste disposal were also assessed for the solvents

  18. 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....... The headspace concentrations of all the chlorinated solvents except CH3CCl3 were significantly (P less than or equal to 0.05) lower after 41 days in biologically active batches as compared to sterile batches. For the compounds with significantly decreasing headspace concentrations, the decline was the least...... experiments designed to simulate denitrifying conditions in water unsanstrated by measuring the release of N-15 in N-2 to the headspace from added N-15 labeled nitrate. The degradation of chlorinated aliphatic compounds was followed by measuring their concentrations in the headspace above the soil...

  19. Chlorination separation of uranium, thorium, and radium from low-grade ores

    International Nuclear Information System (INIS)

    Sastri, V.S.; Perumareddi, J.R.

    1995-01-01

    Low-temperature chlorination of low-grade uranium ores containing uranium in the 0.02 to 0.06% range, thorium in the 0.036 to 0.12% range, and radium in the 70 to 200 pci/g range resulted in the extraction of >90% of the constituents. The residue left after chlorination was found to be innocuous and suitable for disposal as a waste acceptable to the environment. Use of sodium chloride in the charge was useful in reducing the chlorination temperature and in the formation of nonvolatile anionic chloro complexes of the metal ions in the ore

  20. A study of the characteristics of indium tin oxide after chlorine electro-chemical treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moonsoo; Kim, Jongmin; Cho, Jaehee; Kim, Hyunwoo; Lee, Nayoung; Choi, Byoungdeog, E-mail: bdchoi@skku.edu

    2016-10-15

    Graphical abstract: The presence of Chlorine in the outer surface resulted in a highly electro-negative surface states and an increase in the vacuum energy level. - Highlights: • We investigated the influence of chlorine surface treatment on ITO properties. • Chlorination induced the change of the electro-static potential in the outer surface. • Chlorine electro-chemical treatment of ITO is a simple, fast and effective technique. - Abstract: In this work, we investigate the influence of a chlorine-based electro-chemical surface treatment on the characteristics of indium tin oxide (ITO) including the work function, chemical composition, and phase transition. The treated ITOs were characterized using X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS), 4-point probe measurements, and grazing incidence X-ray diffraction (GI-XRD). We confirmed a change of the chemical composition in the near-surface region of the ITO and the formation of indium-chlorine (In-Cl) bonds and surface dipoles (via XPS). In particular, the change of the electro-static potential in the outer surface was caused by chlorination. Due to the vacuum-level shift after the electro-chemical treatment in a dilute hydrochloric acid, the ITO work function was increased by ∼0.43 eV (via UPS); furthermore, the electro-negativity of the chlorine anions attracted electrons to emit them from the hole transport layer (HTL) to the ITO anodes, resulting in an increase of the hole-injection efficiency.

  1. Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

    Directory of Open Access Journals (Sweden)

    Shuangxi Nie

    2014-07-01

    Full Text Available In this paper, a kinetic model of the first chlorine dioxide bleaching stage (D0 in an elemental chlorine-free (ECF bleaching sequence is presented for bagasse pulps. The model is based on the rate of adsorbable organic halogen (AOX formation. The effects of the chlorine dioxide dosage, the sulfuric acid dosage, and the reaction temperature on the AOX content of wastewater are examined. The reaction of AOX formation could be divided into two periods. A large amount of AOX was formed rapidly within the first 10 min. Ten minutes later, the AOX formation rate significantly decreased. The kinetics could be expressed as: dW⁄dt=660.8•e^(-997.98/T 〖•[ClO〗_2 ]^0.877•[H2SO4 ]^0.355•W^(-1.065, where W is the AOX content, t is the bleaching time (min, T is the temperature (K, [ClO2] is the dosage of chlorine dioxide (kg/odt, and [H2SO4] is the dosage of sulfuric acid (kg/odt. The fit of the experiment results obtained for different temperatures, initial chlorine dioxide dosages, initial sulfuric acid dosages, and AOX content were very good, revealing the ability of the model to predict typical mill operating conditions.

  2. Determination of chlorine in coal by X-ray fluorescence spectrometry method

    Energy Technology Data Exchange (ETDEWEB)

    Marek, S.; Bojarska, K. [Central Mining Institute, Katowice (Poland). Dept. of Environmental Monitoring

    1997-12-31

    Determination of chlorine contents in coal is essential for both environmental protection and its technological use. The existing method of chlorine determination in coal are titration methods which have considerable errors particularly in the low concentration range. The elaborated method with the use of X-ray fluorescence spectrometry in a comparison to the other methods is much faster and has better precision and accuracy. The principle of the method lies in the measurement of X-ray fluorescence radiation intensity which is emitted by chlorine in a sample and its comparison with standards. The calibration of the elaborated XRF method is based on natural coals having various concentrations of chlorine within the whole range of its occurrence in Polish coals. Concentrations for the calibration purpose were obtained by the determination of chlorine contents in selected coals by atomic absorption spectrometry method. The procedure of sample preparation for direct X-ray measurements, instrumental measuring conditions and the way of calibration curve preparation are described in the paper. All X-ray measurements were done with a Phillips sequential X-ray fluorescence spectrometer. A double anode Cr-Au X-ray tube with maximum power 3000 MW was used as the excitation source. 5 figs., 4 tabs.

  3. Constraining wintertime sources of inorganic chlorine over the northeast United States

    Science.gov (United States)

    Haskins, J.; Jaegle, L.; Shah, V.; Lopez-Hilfiker, F.; Lee, B. H.; Campuzano Jost, P.; Schroder, J. C.; Day, D. A.; Fiddler, M. N.; Holloway, J. S.; Sullivan, A.; Veres, P. R.; Weber, R. J.; Dibb, J. E.; Brown, S. S.; Jimenez, J. L.; Thornton, J. A.

    2017-12-01

    Wintertime multiphase chlorine chemistry is thought to play a significant role in the regional distribution of oxidants, the lifetime of VOCs, and the transport of NOx downwind of urban sources. However, the sources and chemistry of reactive chlorine remain highly uncertain. During the WINTER 2015 aircraft campaign, the inorganic chlorine budget was dominated by HCl (g) and total particulate chloride, accounting for greater than 85% of the total chlorine budget within the boundary layer. The total concentration of inorganic chlorine compounds found over marine regions was 1014 pptv and 609 pptv over continental regions with variability found to be driven by changes in meteorological conditions, particle liquid water content, particle pH, and proximity to large anthropogenic sources. However, displacement of particle chloride was often not a large enough source to fully explain the concentrations of gas phase Cly compounds. We use the GEOS-Chem global chemical transport model to simulate the emissions, gas-particle partitioning, and downwind transport and deposition of Cly during winter. Simulated concentrations of HCl, particle chloride, and other dominant Cly compounds are compared to measurements made during the WINTER aircraft campaign. The relative roles of Cly sources from sea-salt aerosol and anthropogenic sources such as power plants, biomass burning and road salt are explored.

  4. 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

  5. Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control.

    Directory of Open Access Journals (Sweden)

    Qing-Bin Yuan

    Full Text Available This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L. The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L. By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L. However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.

  6. Sulfonate activation of the electrophilic reactivity of chlorine and alkyl hypochlorides by the insertion of sulfur trioxide at the C1-C1 and O-C1 bonds. Addition of chlorine chloro- and ethoxysulfate to olefins

    International Nuclear Information System (INIS)

    Zefirov, N.S.; Koz'min, A.S.; Sorokin, V.D.; Zhdankin, V.V.

    1986-01-01

    At low temperatures (-40 to -80 0 C) sulfur trioxide enters the chlorine molecule (with the formation of chlorine chlorosulfate) and the ethyl hypochlorite molecule (giving chlorine ethoxysulfate). Both new compounds are highly reactive electrophilic chlorinating reagents and add to ethylene, activated alkenes (1-hexene and cyclohexene), and deactivated olefins (methyl methacrylate, tri- and tetrachloroethylene) in methylene chloride solution at low temperatures. The addition of chlorine chlorosulfate leads to the formation of β-chloroalkyl chlorosulfates with yields of 24-85%, and the addition of chlorine ethoxysulfate leads to β-chloroalkyl ethylsulfates with yields of 65-85%. The reactions with unsymmetrical olefins lead to mixtures of the regioisomers with a preference for the products from addition according to the Markovnikov rule; the addition to cyclohexene is trans-stereospecific. The investigated processes represent a new simple approach to the production of sulfate-activated chlorinating reagents and extend the possibilities for functional substitution of olefins

  7. Robust Chemiresistive Sensor for Continuous Monitoring of Free Chlorine Using Graphene-like Carbon.

    Science.gov (United States)

    Aryasomayajula, Aditya; Wojnas, Caroline; Divigalpitiya, Ranjith; Selvaganapathy, Ponnambalam Ravi; Kruse, Peter

    2018-02-23

    Free chlorine is widely used in industry as a bleaching and oxidizing agent. Its concentration is tightly monitored to avoid environmental contamination and deleterious human health effects. Here, we demonstrate a solid state chemiresistive sensor using graphene like carbon (GLC) to detect free chlorine in water. A 15-20 nm thick GLC layer on a PET substrate was modified with a redox-active aniline oligomer (phenyl-capped aniline tetramer, PCAT) to increase sensitivity, improve selectivity, and impart fouling resistance. Both the bare GLC sensor and the PCAT-modified GLC sensor can detect free chlorine continuously and, unlike previous chemiresistive sensors, do not require a reset. The PCAT-modified sensor showed a linear response with a slope of 13.89 (mg/L) -1 to free chlorine concentrations between 0.2 and 0.8 mg/L which is relevant for free chlorine monitoring for drinking water and wastewater applications. The PCAT-modified GLC sensors were found to be selective and showed less than 0.5% change in current in response to species such as nitrates, phosphates and sulfates in water. They also were resistant to fouling from organic material and showed only a 2% loss in signal. Tap water samples from residential area were tested using this sensor which showed good agreement with standard colorimetric measurement methods. The GLC and PCAT-GLC sensors show high sensitivity and excellent selectivity to free chlorine and can be used for continuous automated monitoring of free chlorine.

  8. [Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

    Science.gov (United States)

    Onodera, Sukeo

    2010-09-01

    This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

  9. 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.

  10. Degradation of natural organic matter by UV/chlorine oxidation: Molecular decomposition, formation of oxidation byproducts and cytotoxicity.

    Science.gov (United States)

    Wang, Wen-Long; Zhang, Xue; Wu, Qian-Yuan; Du, Ye; Hu, Hong-Ying

    2017-11-01

    The degradation of natural organic matters (NOMs) by the combination of UV and chlorine (UV/chlorine) was investigated in this study. UV/chlorine oxidation can effectively degrade NOMs, with the degradation of chromophores (∼80%) and fluorophores (76.4-80.8%) being more efficient than that of DOC (15.1-18.6%). This effect was attributed to the chromophores and fluorophores (double bonds, aromatic groups and phenolic groups) being preferentially degraded by UV/chlorine oxidation, particularly reactive groups with high electron donating capacity. Radical species •OH and •Cl were generated during UV/chlorine oxidation, with the contribution of •OH 1.4 times as high as that of •Cl. The degradation kinetics of different molecular weight (MW) fractions suggests that UV/chlorine oxidation degrades high MW fractions into low MW fractions, with the degradation rates of high MW fractions (>3000 Da) 4.5 times of those of medium MW fractions (1000-3000 Da). In comparison with chlorination alone, UV/chlorine oxidation did not increase the formation (30 min) and formation potential (24 h) of trihalomethanes, but instead promoted the formation and formation potential of haloacetic acids and chloral hydrate. Adsorbable organic halogen (AOX) formed from UV/chlorine oxidation of NOM were 0.8 times higher than those formed from chlorination. Cytotoxicity studies indicated that the cytotoxicity of NOM increased after both chlorination and UV/chlorine oxidation, which may be due to the formation of AOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Evaluation of Chlorinated Hydrocarbon Concentrations in Tehran’s Districts Drinking Water

    Directory of Open Access Journals (Sweden)

    Alireza Pardakhti

    2012-01-01

    Full Text Available In this study Tehran’s drinking water was evaluated for the presence of chlorinated hydrocarbons during spring and summer of 2009. Chlorinated hydrocarbons are an important class of environmental pollutants that cause adverse health effects on human’s kidney, liver and central nervous systems. In this study six water districts were selected for taking drinking water samples in the city of Tehran as well as one location outside the city limits. The samples were analyzed by GC/MS using EPA method 8260. The average concentrations of 1,1-dichloroethylene, 1,2 Dichloromethane, Tetra chloromethane, Trichloroethylene and tetra chloroethylene were determined during a 7 month period and the results were 0.04ppb, 0.52ppb, 0.01ppb, 0.24ppb, 0.03ppb respectively. The highest concentration of chlorinated hydrocarbon observed in Tehran’s drinking water was Trichloroethylene and the lowest concentration was Tetra chloromethane. Districts 5 and 6 showed the highest concentrations of chlorinated hydrocarbons in the city of Tehran.

  12. Influence of nitrogen source on NDMA formation during chlorination of diuron.

    Science.gov (United States)

    Chen, Wei-Hsiang; Young, Thomas M

    2009-07-01

    N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N'-(3,4-dichlorophenyl)-N,N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitriteNDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface water and groundwater in nitrogen forms and concentrations and disinfection approaches suggest strategies to reduce NDMA formation should vary with drinking water source.

  13. Kinetic investigation of the chlorine reduction reaction on electrochemically oxidised ruthenium

    International Nuclear Information System (INIS)

    Thomassen, M.; Karlsen, C.; Borresen, B.; Tunold, R.

    2006-01-01

    The rate and mechanism of the electroreduction of chlorine on electrooxidised ruthenium has been investigated with focus on the effect of solution pH. Current/potential curves for the reduction process in solutions with constant chloride concentration of 1.0 mol dm -3 and varying H + concentration have been obtained with the use of the rotating disk electrode technique (RDE). It was found that the chlorine reduction rate is highly inhibited in solutions with high H + concentrations and that it can be satisfactorily described by the Erenburg mechanism, previously suggested for the chlorine evolution on RuO 2 and RTO. The expression of the kinetic current as a function of chlorine and H + concentration was obtained by solving the elementary rate equations of the kinetic mechanism. The kinetic constants obtained from the correlation of the kinetic current expression to the experimental data were used to simulate the dependence of the surface coverages and elementary reaction rates on overpotential

  14. Influence of Nitrogen Source on NDMA Formation during Chlorination of Diuron

    Science.gov (United States)

    Chen, Wei-Hsiang; Young, Thomas M.

    2009-01-01

    N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite diuron dose. Formation of dichloramine seemed to fully explain enhanced NDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface and groundwater in nitrogen forms and concentrations and disinfection approaches, suggest strategies to reduce NDMA formation should vary with drinking water source. PMID:19457535

  15. Chlorinated paraffin analysis by gas chromatography Orbitrap high-resolution mass spectrometry: Method performance, investigation of possible interferences and analysis of fish samples.

    Science.gov (United States)

    Krätschmer, Kerstin; Cojocariu, Cristian; Schächtele, Alexander; Malisch, Rainer; Vetter, Walter

    2018-03-02

    For decades, high quantities of short-chain chlorinated paraffins (SCCP) and medium-chain chlorinated paraffins (MCCP) have been widely used, for instance as plasticizers or flame retardants, leading to global pollution due to unintentional emissions from products or waste. Due to the high complexity of chlorinated paraffins with several thousand congeners there is no consensus on an analytical procedure for SCCPs and MCCPs in food samples. Amongst the multitude of methods currently in use, high-resolution mass spectrometry is particularly valuable for in-depth studies of homologue patterns. Here we analyse SCCPs and MCCPs with gas chromatography coupled to high-resolution Orbitrap mass spectrometry (GC-Orbitrap-HRMS) operated in full-scan acquisition in electron capture negative ion (ECNI) mode at 60,000 and 120,000 resolution (FWHM, m/z 200, equals roughly 30,000 and 60,000 at 5% peak height). Linear dynamic range, selectivity and sensitivity tests confirmed an excellent linearity in a concentration range of 25-15,000 pg/μL with very low limits of detection (LODs) in the low pg/μL range. Spiking experiments with high levels of native mono- and di-ortho-polychlorinated biphenyls (PCBs) and mixtures of MCCP and SCCP standards did not have a negative impact on isotope ratios of the examined homologues. Besides the [M-Cl] - fragment ions used for quantification, the mass spectra of homologues also featured [M-HCl] - ions whose abundance increased with decreasing chlorination degree. In addition, [M-HCl-Cl] - ions were detected with a relative abundance of 5-10%. Three salmon (Salmo salar) samples farmed in Norway showed a consistent CP homologue pattern which differed both from the CP pattern in a sample from Scottish aquaculture and a wild salmon sample. These measurements produce evidence that discretely different CP patterns may exist in different areas of origin. Our results demonstrate that GC/ECNI-Orbitrap-HRMS is well-suited for the analysis of CPs by

  16. Congener-specific accumulation and trophic transfer of polychlorinated biphenyls in spider crab food webs revealed by stable isotope analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, N. [IFREMER, DCN-BE, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France); LPTC-UMR 5472 CNRS, Universite de Bordeaux 1, 351 cours de la Liberation, 33400 Talence (France)], E-mail: bodin.nathalie@caramail.com; Le Loc' h, F. [IRD, UR 070 RAP, Centre de Recherche Halieutique, Avenue Jean Monnet, B.P. 171, 34203 Sete Cedex (France); Caisey, X.; Le Guellec, A.-M.; Abarnou, A.; Loizeau, V. [IFREMER, DCN-BE, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France); Latrouite, D. [IFREMER, DCB-STH, Technopole Brest-Iroise, Pointe du Diable, 29280 Plouzane (France)

    2008-01-15

    Polychlorobiphenyls (PCB) and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C) were analyzed in the spider crab (Maja brachydactyla) food web from the Iroise Sea (Western Brittany) and the Seine Bay (Eastern English Channel). PCB concentrations were all significantly higher in organisms from the Seine Bay than those from the Iroise Sea. PCB patterns were strongly related to the feeding mode of the species, and increased influence of higher chlorinated congeners was highlighted with trophic position of the organisms. PCB concentrations (lipid normalized) were significantly related to the isotopically derived trophic level (TL) in spider crab food webs. The highest trophic magnification factors (TMFs) were calculated for the congeners with 2,4,5-substitution, and were lower in the Seine Bay compared to the Iroise Sea. The confrontation of PCB and TL data also revealed biotransformation capacity of decapod crustaceans for specific congeners based on structure-activity relations. - The influence of feeding mode and trophic position on the fate of PCBs in spider crab food webs is discussed by using a stable isotopic approach.

  17. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments

    International Nuclear Information System (INIS)

    Li, Jian; Ma, Li-yun; Xu, Li

    2016-01-01

    Highlights: • Chlorination kinetics of three benzophenone-type UV filters (BPs) was studied. • Chlorination of BPs followed second-order reaction. • The transformation products (TPs) of six BPs were identified. • Several transformation pathways were proposed. • Mostly enhanced toxicity of TPs after chlorination was observed. - Abstract: 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.

  18. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Ma, Li-yun; Xu, Li, E-mail: xulpharm@mails.tjmu.edu.cn

    2016-07-05

    Highlights: • Chlorination kinetics of three benzophenone-type UV filters (BPs) was studied. • Chlorination of BPs followed second-order reaction. • The transformation products (TPs) of six BPs were identified. • Several transformation pathways were proposed. • Mostly enhanced toxicity of TPs after chlorination was observed. - Abstract: 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{sup −1} s{sup −1} for oxybenzone, 49.6–261.7 M{sup −1} s{sup −1} for 4-hydroxybenzophenone and 51.7–540 M{sup −1} s{sup −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.

  19. Epidemiological evidence of carcinogenicity of chlorinated organics in drinking water.

    Science.gov (United States)

    Cantor, K P

    1982-12-01

    Concern has recently been voiced over possible chronic toxicity associated with chlorination of public drinking water supplies in the United States. This paper reviews the available evidence and the studies underway to further evaluate hypothesized associations between cancer risk and byproducts of chlorination. Preliminary data from measures of halogenated volatiles and personal exposure histories from respondents in a large epidemiologic study of bladder cancer are presented. These data support the use in epidemiologic studies of categorical measures of exposure and suggest that results from completed case-control studies, based on death certificates, may have underestimated the true risk of exposure to chlorination by-products. The current generation of studies which use a case-control interview design offer many advantages over earlier efforts to evaluate this issue.

  20. 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...... (direct push delivery, Gl. Kongevej). Degradation of chlorinated ethenes (and ethanes) in the clay till matrix and in embedded high permeability features was investigated by high resolution sampling of intact cores combined with groundwater sampling. An integrated approach using chemical analysis...... (hydraulic fracturing with gravitational injection and direct push delivery) were therefore tested in clay till by injection of amendment-comparable tracers to investigate the possibility to overcome diffusion limitations in the low permeability matrix. The study of hydraulic fracturing demonstrated...

  1. Chlorination of zirconyte concentrate

    International Nuclear Information System (INIS)

    Costa, N.G.

    1988-01-01

    Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO 2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO 2 gasification. (author) [pt

  2. The role and function of chlorine in the preparation of high-ratio cake flour.

    Science.gov (United States)

    Gough, B M; Whitehouse, M E; Greenwood, C T

    1978-01-01

    The literature on the role of chlorine treatment of flour for use in high-ratio cake production is discussed in relation to current knowledge of cereal chemistry and cake technology. A brief perspective of the present use of chlorine in high-ratio cake flours is included. Investigations of the uptake of gaseous chlorine by flour and its distribution among and chemical action upon the major flour components (water, protein, lipid, and carbohydrate) are assessed. The physical effects of chlorination as demonstrated by experiments with batters and cakes and by physicochemical observations of flour and its fractions are also considered. The characteristics of the starch in flour appear to be critical in high-ratio cakes. Chlorine treatment modifies the gelatinization behavior of the starch granules yet does not change their gelatinization temperature not is there evidence of chemical attack upon the starch molecules. Therefore, it is suggested that chlorine effects the necessary changes in starch behavior by reacting with the noncarbohydrate surface contaminants on the granules. Alternative methods of improving high-ratio cake flours are mentioned, particularly heat-treatment processes.

  3. Role of Dehalogenases in Aerobic Bacterial Degradation of Chlorinated Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2014-01-01

    Full Text Available This review was conducted to provide an overview of dehalogenases involved in aerobic biodegradation of chlorinated aromatic compounds. Additionally, biochemical and molecular characterization of hydrolytic, reductive, and oxygenolytic dehalogenases was reviewed. This review will increase our understanding of the process of dehalogenation of chlorinated aromatic compounds.

  4. Chlorination and dechlorination rates in a forest soil — A combined modelling and experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Montelius, Malin, E-mail: malin.montelius@liu.se [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Svensson, Teresia [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Lourino-Cabana, Beatriz [EDF, Laboratoire National d' Hydraulique et Environnement, 78401 Chatou (France); Thiry, Yves [Andra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Bastviken, David [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden)

    2016-06-01

    Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Cl{sub org}). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Cl{sub org} are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Cl{sup −} transformed to Cl{sub org} per time unit) and specific dechlorination (i.e., fraction of Cl{sub org} transformed to Cl{sup −} per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 d{sup −1} and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01–0.03 d{sup −1} and were similar among all treatments. This study finds that soil Cl{sub org} levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Cl{sub org} compounds, while another Cl{sub org} pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils. - Highlights: • Chlorination and dechlorination rates in soil were revealed by a radiotracer method. • Chlorination was hampered by nitrogen addition. • Both Cl{sup −} and many Cl{sub org} compounds are highly reactive in soils. • Some formed Cl{sub org} seem to be refractory.

  5. Reagent-Free Quantification of Aqueous Free Chlorine via Electrical Readout of Colorimetrically Functionalized Pencil Lines.

    Science.gov (United States)

    Mohtasebi, Amirmasoud; Broomfield, Andrew D; Chowdhury, Tanzina; Selvaganapathy, P Ravi; Kruse, Peter

    2017-06-21

    Colorimetric methods are commonly used to quantify free chlorine in drinking water. However, these methods are not suitable for reagent-free, continuous, and autonomous applications. Here, we demonstrate how functionalization of a pencil-drawn film with phenyl-capped aniline tetramer (PCAT) can be used for quantitative electric readout of free chlorine concentrations. The functionalized film can be implemented in a simple fluidic device for continuous sensing of aqueous free chlorine concentrations. The sensor is selective to free chlorine and can undergo a reagent-free reset for further measurements. Our sensor is superior to electrochemical methods in that it does not require a reference electrode. It is capable of quantification of free chlorine in the range of 0.1-12 ppm with higher precision than colorimetric (absorptivity) methods. The interactions of PCAT with the pencil-drawn film upon exposure to hypochlorite were characterized spectroscopically. A previously reported detection mechanism relied on the measurement of a baseline shift to quantify free chlorine concentrations. The new method demonstrated here measures initial spike size upon exposure to free chlorine. It relies on a fast charge built up on the sensor film due to intermittent PCAT salt formation. It has the advantage of being significantly faster than the measurement of baseline shift, but it cannot be used to detect gradual changes in free chlorine concentration without the use of frequent reset pulses. The stability of PCAT was examined in the presence of free chlorine as a function of pH. While most ions commonly present in drinking water do not interfere with the free chlorine detection, other oxidants may contribute to the signal. Our sensor is easy to fabricate and robust, operates reagent-free, and has very low power requirements and is thus suitable for remote deployment.

  6. Characterization of the bacterial community in shower water before and after chlorination

    KAUST Repository

    Peters, Marjolein C. F. M.; Keuten, Maarten G. A.; Knezev, Aleksandra; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.; Rietveld, Luuk C.; de Kreuk, Merle K.

    2017-01-01

    Gram-negative. The dominant bacterial families with a relative abundance of ≥10% of the total (non-chlorinated and chlorinated) communities were Flavobacteriaceae (24–21%), Xanthomonadaceae (23–24%), Moraxellaceae (12–11%) and Pseudomonadaceae (10

  7. Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination.

    Science.gov (United States)

    Zhang, Jinshan; Xue, Jinling; Xu, Bi; Xie, Jiani; Qiao, Juan; Lu, Yun

    2016-02-13

    Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Assessment of residual active chlorine in sodium hypochlorite solutions after dissolution of porcine incisor pulpal tissue.

    Science.gov (United States)

    Clarkson, R M; Smith, T K; Kidd, B A; Evans, G E; Moule, A J

    2013-12-01

    In previous studies, surfactant-containing Hypochlor brands of sodium hypochlorite showed better tissue solubilizing abilities than Milton; differences not explained by original active chlorine content or presence of surfactant. It was postulated that exhaustion of active chlorine content could explain differences. This study aimed to assess whether Milton's poorer performance was due to exhaustion of active chlorine. Parallel experiments assessed the influence of titration methods, and the presence of chlorates, on active chlorine measurements. Time required to dissolve one or groups of 10 samples of porcine incisor pulp samples in Milton was determined. Residual active chlorine was assessed by thermometric titration. Iodometric and thermometric titration was carried out on samples of Milton. Chlorate content was also measured. Dissolution of single and 10 pulp samples caused a mean loss of 1% and 3% respectively of active chlorine, not being proportional to tissue dissolved. Thermometric ammonium ion titration resulted in 10% lower values than iodometric titration. Chlorate accounted for much of this difference. Depletion of active chlorine is not the reason for differences in tissue dissolving capabilities of Milton. Thermometric ammonium ion titration gives more accurate measurement of active chlorine content than iodometric titration. © 2013 Australian Dental Association.

  9. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Lucía I., E-mail: lbarbosa@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); González, Jorge A. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Parque General San Martín, CP M5502JMA Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina)

    2015-04-10

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl{sub 2} on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl{sub 2} at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl{sub 2}Si{sub 2}O{sub 8}, SiO{sub 2}, and CaSiO{sub 3}.

  10. Application of Chlorine-Assisted Chemical Vapor Deposition of Diamond at Low Temperatures

    Science.gov (United States)

    Pan, Chenyu; Altemir, David A.; Margrave, John L.; Hauge, Robert H.

    1994-01-01

    Low temperature deposition of diamond has been achieved by a chlorine-assisted diamond chemical vapor deposition (CA-CVD) process. This method begins with the thermal dissociation of molecular chlorine into atomic chlorine in a resistively heated graphite furnace at temperatures between 1300 and 1500 deg. C. The atomic chlorine, upon mixing, subsequently reacts with molecular hydrogen and hydrocarbons. The rapid exchange reactions between the atomic chlorine, molecular hydrogen, and hydrocarbons give rise to the atomic hydrogen and carbon precursors required for diamond deposition. Homoepitaxial diamond growth on diamond substrates has been studied over the substrate temperature range of 100-950 C. It was found that the diamond growth rates are approximately 0.2 microns/hr in the temperature range between 102 and 300 C and that the growth rates do not decrease significantly with a decrease in substrate temperature. This is unique because the traditional diamond deposition using H2/CH4 systems usually disappears at substrate temperatures below approx. 500 deg. C. This opens up a possible route to the deposition of diamond on low-melting point materials such as aluminum and its alloys.

  11. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    International Nuclear Information System (INIS)

    Barbosa, Lucía I.; González, Jorge A.; Ruiz, María del Carmen

    2015-01-01

    Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl 2 on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl 2 at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl 2 Si 2 O 8 , SiO 2 , and CaSiO 3

  12. Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment.

    Science.gov (United States)

    Adira Wan Khalit, Wan Nor; Tay, Kheng Soo

    2016-05-18

    Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination.

  13. 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. PMID:25734448

  14. 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.

  15. Chlorination and chloramination of aminophenols in aqueous solution: oxidant demand and by-product formation.

    Science.gov (United States)

    Mehrez, O Abou; Dossier-Berne, F; Legube, B

    2015-01-01

    Chlorination and monochloramination of aminophenols (AP) were carried out in aqueous solution at 25°C and at pH 8.5. Oxidant demand and disinfection by-product formation were determined in excess of oxidant. Experiments have shown that chlorine consumption of AP was 40-60% higher than monochloramine consumption. Compared with monochloramination, chlorination of AP formed more chloroform and haloacetic acids (HAA). Dichloroacetic acid was the major species of HAA. Chloroform and HAA represented, respectively, only 1-8% and 14-15% of adsorbable organic halides (AOX) by monochloramination but up to 29% and 39% of AOX by chlorination.

  16. 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.

  17. Organochlorine compounds and the biogeochemical cycle of chlorine in soils: A review

    Science.gov (United States)

    Vodyanitskii, Yu. N.; Makarov, M. I.

    2017-09-01

    Chloride ions in soil may interact with soil organic matter and form organochlorine compounds in situ. The biotic chlorination of soil organic substances takes places under aerobic conditions with participation of H2O2 forming from peroxidases released by soil microorganisms (in particular, by microscopic fungi). The abiotic chlorination results also from the redox reactions with the participation of Fe3+/Fe2+ system, but it develops several times slower. Chlorination of soil organic substances is favored by Cl- coming to soil both from natural (salinized soil-forming rocks and groundwater, sea salt) and anthropogenic sources of chlorides, i.e., spills of saline water at oil production, road deicing chemicals, mineral fertilizers, etc. The study of the biogeochemical chlorine cycle should take into account the presence of organochlorine compounds in soils, in addition to transformation and migration of chloride ions.

  18. Methylated silicates may explain the release of chlorinated methane from Martian soil

    Science.gov (United States)

    Bak, Ebbe N.; Jensen, Svend J. Knak; Nørnberg, Per; Finster, Kai

    2016-01-01

    The only organic compounds that have been detected in the Martian soil are simple chlorinated compounds released from heated surface material. However, the sources of the organic carbon are in dispute. Wind abraded silicates, which are widespread on the Martian surface, can sequester atmospheric methane which generates methylated silicates and thus could provide a mechanism for accumulation of reduced carbon in the surface soil. In this study we show that thermal volatilization of methylated silicates in the presence of perchlorate leads to the production of chlorinated methane. Thus, methylated silicates could be a source of the organic carbon released as chlorinated methane upon thermal volatilization of Martian soil samples. Further, our experiments show that the ratio of the different chlorinated compounds produced is dependent on the mass ratio of perchlorate to organic carbon in the soil.

  19. Clean Bleaching Engineering Practice for Bagasse Pulp: Totally Chlorine-Free and Elemental Chlorine-Free Bleaching Realized with the Same Production Line

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2015-03-01

    Full Text Available The experimental research, process design principles, and engineering practice of a bagasse pulp production line that could run both totally chlorine-free (OPQ(PO and elemental chlorine-free (OPD(EOP bleaching sequences are discussed in this paper. Under specified process conditions, the oxygen delignification rate was up to 50% and the brightness of unbleached pulp increased. The (OPQ(PO sequence bleached pulp had a brightness of 83.1% ISO and an intrinsic viscosity of 888 mL/g, and the (OPD(EOP sequence bleached pulp had a brightness of 85.7% ISO and an intrinsic viscosity of 905 mL/g. Pulp quality produced from both bleaching sequences was better than pulp bleached by the chlorination, alkaline extraction, and hypochlorite (CEH sequence. The wastewater was discharged only from the Q or D stage, and the chemical oxygen demand (COD of Q or D stage was about 650 mg/L or 1100 mg/L, respectively. It was easy to alternate between these two bleaching sequences, and the bleached pulp quality from these sequences was stable.

  20. Investigations of high-temperature chlorination ultramicroquantities of rare earths and thermochromatographic behaviour of their chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Nguen Kong Chang; Novgorodov, A.F.; Kaskevich, M.; Kolachkovski, A.; Khalkin, V.A.

    1984-01-01

    An attempt has been undertaken to accomplish gas thermochromatographic (GTC) separation of trichloride mixture of all lanthanoids. Effect of starting temperature, content and concentration of different chlorinating reagent gases upon the thermochromatographic process has been investigated in order to optimize GTC separation of RSE. Investigations have been carried out using the following REE radioactive isotopes: /sup 140/La, /sup 144/Ce, /sup 147/Nd, /sup 153/Sm, /sup 156/Eu, sup(151, 153)Gd, /sup 160/Yb and /sup 172/Lu, which were preliminary purified at the chromatographic column filled with cationite using ammonium ..cap alpha..-oxiizobtirate, then transformed into a chloride form and dried under vacuum conditions. Pronounced zones of separated REE trichloride asorption, chacterized by a mean square root value of adsorbent distribution sigma=5 K, have been obtained. It has been shown that temperatures of center of gravity of REE trichloride adsorbtion zone are practically equal to each other and, hence it is impossible to perform the GTC separation of their ultramicroamounts.

  1. Migration of chlorinated hydrocarbons in multilayer unconsolidated porous media: a case study from the Po Plain, Italy

    Directory of Open Access Journals (Sweden)

    Maria Filippini

    2017-12-01

    Full Text Available Chlorinated solvents are the most ubiquitous organic contaminants found in groundwater since the last six decades. Due to their high degree of carcinogenicity/toxicity and the relatively high mobility and persistence, they represent a serious threat against the human health and the environment. These contaminants generally reach groundwater as Dense Non-Aqueous Phase Liquid (DNAPL that can migrate through aquifers easier than aqueous contaminants. The complex phase partitioning to which chlorinated solvent DNAPLs can undergo (i.e. to the dissolved, vapor or sorbed phase, as well as their transformations (e.g. degradation, depend on the physico-chemical properties of the contaminants and on the features of the hydrogeological system in which they migrate. The hydrogeologic setting below the city of Ferrara (Po plain, northern Italy, which is affected by scattered contamination by chlorinated solvents, has been investigated. In particular, a limited-inspace high-resolution investigation was performed in one selected contaminated test-site, known as “Caretti site”. Here, high-resolution vertical profiling of different kind of data (i.e. stratigraphic data, hydraulic heads, hydrochemical composition of water, stable isotopes of water and contaminants were collected by means of multilevel monitoring systems and other innovative sampling and analytical techniques. The main goals of the research were to assess the intrinsic vulnerability of the aquifers and to identify the dynamics of migration and transformation of the chloroethene contaminants in relationship to the features of the hosting porous medium. The confined aquifers turned out to be more vulnerable to DNAPLs than aqueous contaminants due to the occurrence of microfractures in the overlying clayey aquitards. The presence of organic-rich deposits in the local stratigraphy enhanced the biodegradation of chloroethenes causing accumulation of Vinyl Chloride. The results are useful at the

  2. Comprehensive Model for Enhanced Biodegradation of Chlorinated Solvents in Groundwater

    Science.gov (United States)

    Kouznetsova, I.; Gerhard, J. I.; Mao, X.; Robinson, C.; Barry, A. D.; Harkness, M.; Mack, E. E.; Dworatzek, S.

    2007-12-01

    SABRE (Source Area BioREmediation) is a public/private consortium whose charter is to de-termine if enhanced anaerobic bioremediation can result in effective treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research and development project is a field site in the United Kingdom containing TCE DNAPL. A comprehensive numerical model for simulating dehalogenation of chlorinated ethenes has been developed. The model considers the kinetic dissolution of DNAPL and nonaqueous organic amendments, bacterial growth and decay, and the interaction of biological and geochemical reactions that might influence biological activity. The model accounts for inhibitory effects of high chlorin-ated solvent concentrations as well as the link between fermentation and dehalogenation due to dynamic hydrogen concentration (the direct electron donor). In addition to the standard biodegradation pathways, sulphate reduction, mineral dissolution and precipitation kinetics are incorporated. These latter processes influence the soil buffering capacity and thus the net acidity generated. One-dimensional simulations were carried out to reproduce the data from columns packed with site soil and groundwater exhibiting both intermediate (250 mg/L) and near solubility (1100 mg/L) TCE concentrations. The modelling aims were to evaluate the key processes underpinning bioremediation success and provide a tool for investigating field sys-tem sensitivity to site data and design variables. This paper will present the model basis and validation and examine sensitivity to key processes including chlorinated ethene partitioning into soybean oil, sulphate reduction, and geochemical influences such as pH and the role of buffering in highly dechlorinating systems.

  3. Chlorinated paraffins wrapping of carbon nanotubes: A theoretical investigation

    Science.gov (United States)

    Ding, Qiuyue; Ding, Ning; Chen, Xiangfeng; Wu, Chi-Man Lawrence

    2018-04-01

    How nanomaterials interact with pollutants is the central for understanding their environmental behavior and practical application. In this work, molecular dynamics (MD) and density functional theoretical (DFT) methods were used to investigated the influence of carbon chain length, degree of chlorination, chain configuration, and chirality of chlorinated paraffin (CP) and diameter of single-walled carbon nanotubes (SWNTs) on the interaction between CPs and SWNTs. The simulation results demonstrated that CP chain length and chlorination degree played considerably important roles in determining interaction strength between SWNTs and CPs. The interaction energies increased with increasing chain length and chlorination degree. The chirality of SWNT exerted negligible influence on the interaction energy between SWNTs and CPs. On the contrary, interaction energy increased with increasing radius of SWNTs due to the surface curvatures. This result was rationalized by considering the decrease in SWNT curvature with increasing radius, which resulted in plane-like CNT wall. The negligible influence of CP chain configurations was attributed to relative flexibility of CP carbon chains, which can wrap on tubes through conformational changes with low-energy barriers. MD results indicated that CPs could adsorb on SWNT surface rapidly in aqueous environment. Charge transfer and electronic density results indicated that the interaction between CPs and SWNTs was physisorption in nature. This work provides fundamental information regarding SWNTs as sorbents for CPs extraction and adsorptive removal from environmental water system.

  4. Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

    Science.gov (United States)

    Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

    2011-01-01

    High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Tools for Management of Chlorinated Solvent - Contaminated Sites

    Science.gov (United States)

    2009-12-03

    Movie Lee Ann Doner – (2008) MS CSU “Sandy aquifers” Image from Fred Payne /ARCADIS New Paradigm After NRC 2005 l~r SERDP. Advancing solvent plume...Situ Bioremediation Using Emulsified  Edible  Oil”   AFCEE (http://www.afcee.brooks.af.mil/products/techtrans/) - “Principles and Practices of Enhanced...Anaerobic Bioremediation of  Chlorinated Solvents”  - “Protocol for In Situ Bioremediation of Chlorinated Solvents Using  Edible  Oil” 232 Short Course

  6. Pepspectives of chlorine application in metallurgy of vanadium

    International Nuclear Information System (INIS)

    Korshunov, B.G.; Kutsenko, S.A.

    1983-01-01

    The most expedient variants of reprocessing of vanadium technical oxide (5), ferrovanadium and converter slags by chlorine technology with production of pure metal are considered. It is shown that production of vanadium by the way of electro- or metallothermal reduction of chlorides provides more plastic metal in comparison with reduction from oxides. The methods of production of VOCl 3 , VCl 4 and vanadium lowest chlorides are considered. Necessity of expansion of production of vanadium chlorine derivatives is dictated as well by their increasing application in different areas of national economy, in particular, as catalysts in organic synthesis

  7. Chlorination of UO2, PuO2, and rare-earth oxides using ZrCl4

    International Nuclear Information System (INIS)

    Sakamura, Yoshiharu; Inoue, Tadashi; Iwai, Takashi; Moriyama, Hirotake

    2001-01-01

    A new chlorination method using ZrCl 4 , which has a high reactivity with oxygen, has been investigated for more efficient oxide treatment. After actinide oxides are chlorinated and dissolved in a molten salt bath, actinide metals can be selectively collected using the electrorefining process. This process is well suited for pyrochemical reprocessing of metallic fuels. In LiCl-KCI eutectic melts, rare-earth oxides (Y 2 O 3 , La 2 O 3 , CeO 2 , and Nd 2 O 3 ) and actinide oxides (UO 2 and PuO 2 ) were chlorinated by adding ZrCl 4 . As a result, rare-earth and actinide elements were dissolved into the salt as trivalent ions and ZrO 2 was precipitated. When an excess of ZrCI 4 was added, oxides in powder form were completely chlorinated in five hours. It was demonstrated that the ZrCI 4 chlorination method, free from corrosive gas such as chlorine, was very simple and useful. (author)

  8. POPULATION DIVERSITY IN MODEL DRINKING WATER BIOFILMS RECEIVING CHLORINE OR MONOCHLORAMINE RESIDUAL

    Science.gov (United States)

    Most water utilities add monochloramine or chlorine as a residual disinfectant in potable water distribution systems (WDS) to control bacterial regrowth. While monochloramine is considered more stable than chlorine, little is known about the fate of this disinfectant or the effec...

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

    NARCIS (Netherlands)

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

    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

  10. Pulse radiolysis investigations on the oxidation of bilirubin by chlorinated peroxyl radicals (Preprint No. RC.18)

    International Nuclear Information System (INIS)

    Mohan, Hari; Gopinathan, C.

    1989-01-01

    Chlorinated peroxyl radicals were observed to oxidize bilirubin. The rate constants, estimated from the formation kinetics of bilirubin cation, were observed to decrease with decrease in the chlorine substitution of various chlorinated peroxyl radicals. (author)

  11. Elaboration in the area of low temperature chlorination of rare-metal crude ore

    International Nuclear Information System (INIS)

    Mirsaidov, U.M.

    2002-01-01

    The chemical base of low temperature chlorination of rare-metal crude ore was elaborated. The chemical nature of chlorination process which pass at low temperature was decoded and scientifically elaborated

  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. 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...

  14. Chlorine toxicity to copepods: implications in the context of zooplankton entrainment in power plants

    International Nuclear Information System (INIS)

    Ershath, M.; Altaff, K.; Sriyutha Murthy, P.; Venugopalan, V.P.

    2008-01-01

    Full text: Experiments were conducted to assess the effects of chlorine on zooplankton, such as those entrained into cooling water circuits of power stations. Three copepod groups (Calanoida, Cyclopoida and Harpacticoida) and copepod naupliar stages were chosen for the study. Percentage mortality of the different groups of copepods and the naupliar stages was assessed after 5, 15, 30, 45 and 60 min of exposure to chlorine residuals of 0.2, 0.5, 0.8 and 1.0 mg/1. Mortality increased with increase in exposure time and concentration of the biocide. Calanoids were relatively more tolerant to chlorine compared to the other groups. Chlorine toxicity may be classified (from more tolerant to less tolerant) as calanoids > cyclopoida > harpacticoids > naupliar stages. Continuous chlorination (with total chlorine residuals of 0.1 - 0.3 mg/l at the discharge) is the general practice adopted in tropical power stations. Considering this, results of the present study indicate and expected percentage mortality of the different groups as: calanoids - 7.9%, cyclopoids - 11.1%, harpacticoids - 10.2% and naupliar stages - 21.6%. However, the data need to be verified under actual plant conditions. (author)

  15. Detection of chlorine in water

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Mrázek, Jan; Podrazký, Ondřej; Seidl, Miroslav; Aubrecht, Jan; Tobiška, Petr; Pospíšilová, Marie; Matějec, Vlastimil; Kovács, B.; Markovics, A.; Szili, M.

    2009-01-01

    Roč. 139, č. 1 (2009), s. 139-142 ISSN 0925-4005 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fiber sensor * chlorine Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.083, year: 2009

  16. Sequential use of ultraviolet light and chlorine for reclaimed water disinfection

    Institute of Scientific and Technical Information of China (English)

    Xiujuan Wang; Xuexiang Hu; Chun Hu; Dongbin Wei

    2011-01-01

    Several disinfection processes of ultraviolet (UV),chlorine or UV followed by chlorine were investigated in municipal wastewater according to the inactivation of Escherichia coli,Shigella dysenteriae and toxicity formation.The UV inactivation of the tested pathogenic bacteria was not affected by the quality of water.It was found that the inactivated bacteria were obviously reactivated after one day in dark.Fluorescent light irradiation increased the bacteria repair.The increase of UV dosage could cause more damage to bacteria to inhibit bacteria self-repair.No photoreactivation was detected when the UV dose was up to 80 mJ/cm2 for E.coli DH5α,and 23 mJ/cm2 for S.dysenteriae.Nevertheless,sequential use of 8 mJ/cm2 of UV and low concentration of chlorine (1.5mg/L) could effectively inhibit the photoreactivation and inactivate E.coli below the detection limits within seven days.Compared to chlorination alone,the sequential disinfection decreased the genotoxicity of treated wastewater,especially for the sample with high NH3-N concentration.

  17. Evaluation of Chlorine Treatment Levels for Inactivation of Human Norovirus and MS2 Bacteriophage during Sewage Treatment.

    Science.gov (United States)

    Kingsley, David H; Fay, Johnna P; Calci, Kevin; Pouillot, Régis; Woods, Jacquelina; Chen, Haiqiang; Niemira, Brendan A; Van Doren, Jane M

    2017-12-01

    This study examined the inactivation of human norovirus (HuNoV) GI.1 and GII.4 by chlorine under conditions mimicking sewage treatment. Using a porcine gastric mucin-magnetic bead (PGM-MB) assay, no statistically significant loss in HuNoV binding (inactivation) was observed for secondary effluent treatments of ≤25 ppm total chlorine; for both strains, 50 and 100 ppm treatments resulted in ≤0.8-log 10 unit and ≥3.9-log 10 unit reductions, respectively. Treatments of 10, 25, 50, and 100 ppm chlorine inactivated 0.31, 1.35, >5, and >5 log 10 units, respectively, of the norovirus indicator MS2 bacteriophage. Evaluation of treatment time indicated that the vast majority of MS2 and HuNoV inactivation occurred in the first 5 min for 0.2-μm-filtered, prechlorinated secondary effluent. Free chlorine measurements of secondary effluent seeded with MS2 and HuNoV demonstrated substantial oxidative burdens. With 25, 50, and 100 ppm treatments, free chlorine levels after 5 min of exposure ranged from 0.21 to 0.58 ppm, from 0.28 to 16.7 ppm, and from 11.6 to 53 ppm, respectively. At chlorine treatment levels of >50 ppm, statistically significant differences were observed between reductions for PGM-MB-bound HuNoV (potentially infectious) particles and those for unbound (noninfectious) HuNoV particles or total norovirus particles. While results suggested that MS2 and HuNoV (measured as PGM-MB binding) behave similarly, although not identically, both have limited susceptibility to chlorine treatments of ≤25 ppm total chlorine. Since sewage treatment is performed at ≤25 ppm total chlorine, targeting free chlorine levels of 0.5 to 1.0 ppm, these results suggest that traditional chlorine-based sewage treatment does not inactivate HuNoV efficiently. IMPORTANCE HuNoV is ubiquitous in sewage. A receptor binding assay was used to assess inactivation of HuNoV by chlorine-based sewage treatment, given that the virus cannot be routinely propagated in vitro Results reported here

  18. Minimization of zirconium chlorinator residues

    International Nuclear Information System (INIS)

    Green, G.K.; Harbuck, D.D.

    1995-01-01

    Zirconium chlorinator residues contain an array of rare earths, scandium, unreacted coke, and radioactive thorium and radium. Because of the radioactivity, the residues must be disposed in special waste containment facilities. As these sites become more congested, and with stricter environmental regulations, disposal of large volumes of wastes may become more difficult. To reduce the mass of disposed material, the US Bureau of Mines (USBM) developed technology to recover rare earths, thorium and radium, and unreacted coke from these residues. This technology employs an HCl leach to solubilize over 99% of the scandium and thorium, and over 90% of the rare earths. The leach liquor is processed through several solvent extraction stages to selectively recover scandium, thorium, and rare earths. The leach residue is further leached with an organic acid to solubilize radium, thus allowing unreacted coke to be recycled to the chlorinator. The thorium and radium waste products, which comprise only 2.1% of the original residue mass, can then be sent to the radioactive waste facility

  19. Epidemiological evidence of carcinogenicity of chlorinated organics in drinking water.

    OpenAIRE

    Cantor, K P

    1982-01-01

    Concern has recently been voiced over possible chronic toxicity associated with chlorination of public drinking water supplies in the United States. This paper reviews the available evidence and the studies underway to further evaluate hypothesized associations between cancer risk and byproducts of chlorination. Preliminary data from measures of halogenated volatiles and personal exposure histories from respondents in a large epidemiologic study of bladder cancer are presented. These data sup...

  20. A micromachined electrochemical sensor for free chlorine monitoring in drinking water.

    Science.gov (United States)

    Mehta, A; Shekhar, H; Hyun, S H; Hong, S; Cho, H J

    2006-01-01

    In this work, we designed, fabricated and tested a disposable, flow-through amperometric sensor for free chlorine determination in water. The sensor is based on the principle of an electrochemical cell. The substrate, as well as the top microfluidic layer, is made up of a polymer material. The advantages include; (a) disposability from low cost; (b) stable operation range from three-electrode design; (c) fluidic interconnections that provide on line testing capabilities; and (d) transparent substrate which provides for future integration of on-chip optics. The sensor showed a good response and linearity in the chlorine concentration ranging from 0.3 to 1.6 ppm, which applies to common chlorination process for drinking water purification.

  1. 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)

  2. Development and evaluation of analytical techniques for total chlorine in burner fuels

    International Nuclear Information System (INIS)

    Gaskill, A. Jr.; Estes, E.D.; Hardison, D.L.; Friedman, P.H.

    1987-01-01

    A current EPA regulation prohibits the sale for burning in non-industrial boilers of used oils and oil fuels contaminated above specified levels with certain metals and total chlorine. When burned as fuel in a small boiler, the contaminants may be emitted to the ambient air at hazardous levels. This regulation establishes a rebuttable presumption that used oil containing more than 1,000 ppm total chlorine has been mixed with halogenated solvents and is a hazardous waste. Rebutting the presumption requires the seller of the oil to prove that this chlorine is not due to halogenated solvents or other hazardous halogenated organics. If the rebuttal is successful, the oil can be sold as fuel up to a level of 4000 ppm total chlorine. Analytical techniques for determination of total chlorine were evaluated or developed to provide regulatory agencies and the regulated community with appropriate chlorine test methods. The techniques evaluated included chemical titrations following oxygen bomb combustion, disposable field test kits, instrumental microcoulometry, and x-ray fluorescence spectrometry. These candidate techniques were subjected to interlaboratory testing to estimate their precision, accuracy, sensitivity, and susceptibility to matrix effects. Information on ease of use and analysis costs was also collected. Based on this pilot study, test methods will be written for the most promising techniques and subjected to a formal collaborative study to generate precision and accuracy data for each method. These methods are to be proposed in the Federal Register as mandatory for compliance with the existing used oil regulation

  3. Mobilization of lead and other trace elements following shock chlorination of wells

    International Nuclear Information System (INIS)

    Seiler, Ralph L.

    2006-01-01

    Many owners of domestic wells shock chlorinate their wells to treat for bacterial contamination or control bad odors from sulfides. Analysis of well water with four wells from Fallon, Nevada, showed that following recommended procedures for shock chlorinating wells can cause large, short-lasting increases in trace-element concentrations in ground water, particularly for Cu, Fe, Pb, and Zn. Lead concentrations increased up to 745 fold between samples collected just before the well was shock chlorinated and the first sample collected 22-24 h later; Zn concentrations increased up to 252 fold, Fe concentrations increased up to 114 fold, and Cu concentrations increased up to 29 fold. Lead concentrations returned to near background levels following pumping of about one casing volume, however, in one well an estimated 120 mg of excess Pb were pumped before concentrations returned to prechlorination levels. Total Pb concentrations were much greater than filtered (0.45 μm) concentrations, indicating the excess Pb is principally particulate. Recommended procedures for purging treated wells following shock chlorination may be ineffective because a strong NaOCl solution can remain in the casing above the pump even following extended pumping. Only small changes in gross alpha and beta radioactivity occurred following shock chlorination. USEPA has not promulgated drinking-water standards for 21 Pb, however, measured 21 Pb activities in the study area typically were less than the Canadian Maximum Acceptable Concentration of 100 mBq/L. By consuming well water shortly after shock chlorination the public may inadvertently be exposed to levels of Pb, and possibly 21 Pb, that exceed drinking-water standards

  4. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

    Science.gov (United States)

    Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

    2017-12-01

    Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Microbial community response to chlorine conversion in a chloraminated drinking water distribution system.

    Science.gov (United States)

    Wang, Hong; Proctor, Caitlin R; Edwards, Marc A; Pryor, Marsha; Santo Domingo, Jorge W; Ryu, Hodon; Camper, Anne K; Olson, Andrew; Pruden, Amy

    2014-09-16

    Temporary conversion to chlorine (i.e., "chlorine burn") is a common approach to controlling nitrification in chloraminated drinking water distribution systems, yet its effectiveness and mode(s) of action are not fully understood. This study characterized occurrence of nitrifying populations before, during and after a chlorine burn at 46 sites in a chloraminated distribution system with varying pipe materials and levels of observed nitrification. Quantitative polymerase chain reaction analysis of gene markers present in nitrifying populations indicated higher frequency of detection of ammonia oxidizing bacteria (AOB) (72% of samples) relative to ammonia oxidizing archaea (AOA) (28% of samples). Nitrospira nitrite oxidizing bacteria (NOB) were detected at 45% of samples, while presence of Nitrobacter NOB could not be confirmed at any of the samples. During the chlorine burn, the numbers of AOA, AOB, and Nitrospira greatly reduced (i.e., 0.8-2.4 log). However, rapid and continued regrowth of AOB and Nitrospira were observed along with nitrite production in the bulk water within four months after the chlorine burn, and nitrification outbreaks appeared to worsen 6-12 months later, even after adopting a twice annual burn program. Although high throughput sequencing of 16S rRNA genes revealed a distinct community shift and higher diversity index during the chlorine burn, it steadily returned towards a condition more similar to pre-burn than burn stage. Significant factors associated with nitrifier and microbial community composition included water age and sampling location type, but not pipe material. Overall, these results indicate that there is limited long-term effect of chlorine burns on nitrifying populations and the broader microbial community.

  6. Development and assessment of countermeasure formulations for treatment of lung injury induced by chlorine inhalation

    Energy Technology Data Exchange (ETDEWEB)

    Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States); Chen, Jing; Schlueter, Connie F.; Mo, Yiqun; Humphrey, David M. [Department of Environmental and Occupational Health Sciences, School of Public Health and Information Sciences, University of Louisville, Louisville, KY (United States); Rawson, Greg; Niño, Joe A.; Carson, Kenneth H. [Microencapsulation and Nanomaterials Department, Chemistry and Chemical Engineering Division, Southwest Research Institute, San Antonio, TX (United States)

    2016-05-01

    Chlorine is a commonly used, reactive compound to which humans can be exposed via accidental or intentional release resulting in acute lung injury. Formulations of rolipram (a phosphodiesterase inhibitor), triptolide (a natural plant product with anti-inflammatory properties), and budesonide (a corticosteroid), either neat or in conjunction with poly(lactic:glycolic acid) (PLGA), were developed for treatment of chlorine-induced acute lung injury by intramuscular injection. Formulations were produced by spray-drying, which generated generally spherical microparticles that were suitable for intramuscular injection. Multiple parameters were varied to produce formulations with a wide range of in vitro release kinetics. Testing of selected formulations in chlorine-exposed mice demonstrated efficacy against key aspects of acute lung injury. The results show the feasibility of developing microencapsulated formulations that could be used to treat chlorine-induced acute lung injury by intramuscular injection, which represents a preferred route of administration in a mass casualty situation. - Highlights: • Chlorine causes lung injury when inhaled and is considered a chemical threat agent. • Countermeasures for treatment of chlorine-induced acute lung injury are needed. • Formulations containing rolipram, triptolide, or budesonide were produced. • Formulations with a wide range of release properties were developed. • Countermeasure formulations inhibited chlorine-induced lung injury in mice.

  7. Fluorine and chlorine determination in oxides and metals by ion chromatography

    International Nuclear Information System (INIS)

    Evseeva, T.I.; Poletaeva, I.L.; Zemlyanukhina, N.A.; Pavlova, I.V.; Rybin, A.M.; Malykh, M.Yu.; Fedorova, L.A.

    1989-01-01

    Method for simultaneous determination of fluorine and chlorine microquantitie in tantalum, uranium and plutonium oxides, based on combined methods of pyrohydrolysis (1000-1100 deg C) and two-column ion chromatography with conductometric detection is suggested. The relative root-mean-square deviation of determination error is 0.2, the fluorine and chlorine content being 5·10 -4 mass%

  8. Comparison of chlorine and chloramine in the release of mercury from dental amalgam.

    Science.gov (United States)

    Stone, Mark E; Scott, John W; Schultz, Stephen T; Berry, Denise L; Wilcoxon, Monte; Piwoni, Marv; Panno, Brent; Bordson, Gary

    2009-01-01

    The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

  9. Health effects from swimming training in chlorinated pools and the corresponding metabolic stress pathways.

    Directory of Open Access Journals (Sweden)

    Jiang-Hua Li

    Full Text Available Chlorination is the most popular method for disinfecting swimming pool water; however, although pathogens are being killed, many toxic compounds, called disinfection by-products (DBPs, are formed. Numerous epidemiological publications have associated the chlorination of pools with dysfunctions of the respiratory system and with some other diseases. However, the findings concerning these associations are not always consistent and have not been confirmed by toxicological studies. Therefore, the health effects from swimming in chlorinated pools and the corresponding stress reactions in organisms are unclear. In this study, we show that although the growth and behaviors of experimental rats were not affected, their health, training effects and metabolic profiles were significantly affected by a 12-week swimming training program in chlorinated water identical to that of public pools. Interestingly, the eyes and skin are the organs that are more directly affected than the lungs by the irritants in chlorinated water; instead of chlorination, training intensity, training frequency and choking on water may be the primary factors for lung damage induced by swimming. Among the five major organs (the heart, liver, spleen, lungs and kidneys, the liver is the most likely target of DBPs. Through metabolomics analysis, the corresponding metabolic stress pathways and a defensive system focusing on taurine were presented, based on which the corresponding countermeasures can be developed for swimming athletes and for others who spend a lot of time in chlorinated swimming pools.

  10. 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 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 (kchlorine 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.

  11. 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

    To investigate whether biotransport constitutes an entry route into pristine ecosystems for nonpersistent, nonvolatile xenobiotic compounds, extractable organically bound halogen in sockeye salmon (Oncorhynchus nerka) from Alaska was determined before and after spawning migration. The major...... 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...

  12. 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.

  13. 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.

  14. 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.

  15. Aqueous-chlorine leaching of typical Canadian uranium ores

    International Nuclear Information System (INIS)

    Haque, K.E.

    1982-01-01

    Laboratory-scale aqueous-chlorine leaches were conducted on quartz-pebble conglomerates, pegmatite and vein-type ores. Optimum leach temperatures, pulp density and retention times were determined. Uranium extraction of 98 per cent was obtained from the Elliot Lake, Madawaska Mines of Bancroft and Rabbit Lake ores, 96 per cent from the Key Lake ore and 86 per cent from the Agnew Lake ore. However, tailings containing 15-20 pCi g -1 of radium-226 were obtained only from the Elliot Lake and Agnew lake quartz-pebble conglomerates and Bancroft pegmatite-type ores by second-stage leaches with HCl. The second-stage leach results indicate that multistage (3 or 4) acid-chloride or salt-chloride leaches might be effective to obtain tailings containing 15-20 pCi 226 Ra g -1 from the high-grade vein-type ores. Comparative reagent-cost estimates show that the sulphuric-acid leach process is far less expensive than aqueous chlorine leaching. Nevertheless, only the aqueous chlorine and acid-chloride leaches in stages are effective in producing tailings containing 15-20 pCi 226 Ra g -1 from the typical Canadian uranium ores. (Auth.)

  16. Chlorination or monochloramination: Balancing the regulated trihalomethane formation and microbial inactivation in marine aquaculture waters

    KAUST Repository

    Sanawar, Huma

    2017-08-15

    Disinfection methods like chlorination are increasingly used to sanitize the water, equipment, tools and surfaces in aquaculture facilities. This is to improve water quality, and to maintain a hygienic environment for the well-being of aquatic organisms. However, chlorination can result in formation of regulated disinfection byproducts (DBPs) that can be carcinogenic and toxic. This study aims to evaluate if an optimal balance can be achieved between minimal regulated DBP formation and effective microbial inactivation with either chlorination or monochloramination for application in the Red Sea aquaculture waters. Upon chlorination, the concentration of total trihalomethanes (THMs), primarily bromoform, exceeded the regulatory limit of 80μg/L even at the lowest tested concentration of chlorine (1mg/L) and contact time (1h). Comparatively, regulated THMs concentration was only detectable at 30μg/L level in one of the three sets of monochloraminated marine aquaculture waters. The average log reduction of antibiotic-resistant bacteria (ARB) by chlorine ranged from 2.3-log to 3.2-log with different contact time. The average log reduction of ARB by monochloramine was comparatively lower at 1.9 to 2.9-log. Although viable Staphylococcus aureus was recovered from monochloraminated samples as opposed to chlorinated samples, the abundance of S. aureus was not high enough to result in any significant microbial risks. Both chlorination and monochloramination did not provide any significant improvement in the reduction of antibiotic resistance genes (ARGs). This study demonstrates that a systematic evaluation is needed to determine the optimal disinfectant required to balance both microbial and chemical risks. Compared to chlorine, monochloramine may be a more appropriate disinfection strategy for the treatment of aquaculture effluents prior to discharge or for recirculatory use in the aquaculture facility.

  17. 40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

    Science.gov (United States)

    2010-07-01

    ... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

  18. 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.

  19. 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.

  20. Chlorinative stress in age-related diseases: a literature review.

    Science.gov (United States)

    Casciaro, Marco; Di Salvo, Eleonora; Pace, Elisabetta; Ventura-Spagnolo, Elvira; Navarra, Michele; Gangemi, Sebastiano

    2017-01-01

    Aging is an agglomerate of biological long-lasting processes that result being inevitable. Main actors in this scenario are both long-term inflammation and oxidative stress. It has been proved that oxidative stress induce alteration in proteins and this fact itself is critically important in the pathophysiological mechanisms leading to diseases typical of aging. Among reactive species, chlorine ones such as hypochlorous acid (HOCl) are cytotoxic oxidants produced by activated neutrophils during chronic inflammation processes. HOCl can also cause damages by reacting with biological molecules. HOCl is generated by myeloperoxidase (MPO) and augmented serum levels of MPO have been described in acute and chronic inflammatory conditions in cardiovascular patients and has been implicated in many inflammatory diseases such as atherosclerosis, neurodegenerative conditions, and some cancers. Due to these data, we decided to conduct an up-to-date review evaluating chlorinative stress effects on every age-related disease linked; potential anti-oxidant countermeasures were also assessed. Results obtained associated HOCl generation to the aging processes and confirmed its connection with diseases like neurodegenerative and cardiovascular pathologies, atherosclerosis and cancer; chlorination was mainly linked to diseases where molecular (protein) alteration constitute the major suspected cause: i.e. inflammation, tissue lesions, DNA damages, apoptosis and oxidative stress itself. According data collected, a healthy lifestyle together with some dietary suggestion and/or the administration of nutracetical antioxidant integrators could balance the effects of chlorinative stress and, in some cases, slow down or prevent the onset of age-releated diseases.

  1. Chlorine-assisted leaching of Key Lake uranium ore

    International Nuclear Information System (INIS)

    Haque, K.E.

    1981-04-01

    Bench-scale chlorine-assisted leach tests were conducted on the Key Lake uranium ore. Leach tests conducted at 80 0 C on a slurry containing 50% solids during 10 hours of agitation gave the maximum extraction of uranium - 96% and radium-226 - 91%. Chlorine was added at 23.0 Kg Cl 2 /tonne of ore to maintain the leach slurry pH in the range of 1.5-1.0. To obtain residue almost free of radionuclides, hydrochloric acid leaches were conducted on the first stage leach residues. The second stage leach residue still was found to contain uranium - 0.0076% and radium-226 - 200 pCi/g of solids

  2. Laboratory tests using chlorine trifluoride in support of deposit removal at MSRE

    International Nuclear Information System (INIS)

    Williams, D.F.; Rudolph, J.C.; Del Cul, G.D.; Loghry, S.L.; Simmons, D.W.; Toth, L.M.

    1997-04-01

    Experimental trials were conducted to investigate some unresolved issues regarding the use of chlorine trifluoride (ClF 3 ) for removal of uranium-bearing deposits in the Molten Salt Reactor Experiment (MSRE) off-gas system. The safety and effectiveness of operation of the fixed-bed trapping system for removal of reactive gases were the primary focus. The chief uncertainty concerns the fate of chlorine in the system and the potential for forming explosive chlorine oxides (primarily chlorine dioxide) in the trapping operation. Tests at the MSRE Reactive Gas Removal System reference conditions and at conditions of low ClF 3 flow showed that only very minor quantities of reactive halogen oxides were produced before column breakthrough. Somewhat larger quantities accompanied breakthrough. A separation test that exposed irradiated MSRE simulant salt to ClF 3 confirmed the expectation that the salt is basically inert for brief exposures to ClF 3 at room temperature

  3. The effect of pH and chloride concentration on the stability and antimicrobial activity of chlorine-based sanitizers.

    Science.gov (United States)

    Waters, Brian W; Hung, Yen-Con

    2014-04-01

    Chlorinated water and electrolyzed oxidizing (EO) water solutions were made to compare the free chlorine stability and microbicidal efficacy of chlorine-containing solutions with different properties. Reduction of Escherichia coli O157:H7 was greatest in fresh samples (approximately 9.0 log CFU/mL reduction). Chlorine loss in "aged" samples (samples left in open bottles) was greatest (approximately 40 mg/L free chlorine loss in 24 h) in low pH (approximately 2.5) and high chloride (Cl(-) ) concentrations (greater than 150 mg/L). Reduction of E. coli O157:H7 was also negatively impacted (pH and high Cl(-) . Higher pH values (approximately 6.0) did not appear to have a significant effect on free chlorine loss or numbers of surviving microbial cells when fresh and aged samples were compared. This study found chloride levels in the chlorinated and EO water solutions had a reduced effect on both free chlorine stability and its microbicidal efficacy in the low pH solutions. Greater concentrations of chloride in pH 2.5 samples resulted in decreased free chlorine stability and lower microbicidal efficacy. © 2014 Institute of Food Technologists®

  4. 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.

  5. Catalysis of copper corrosion products on chlorine decay and HAA formation in simulated distribution systems.

    Science.gov (United States)

    Zhang, Hong; Andrews, Susan A

    2012-05-15

    This study investigated the effect of copper corrosion products, including Cu(II), Cu(2)O, CuO and Cu(2)(OH)(2)CO(3), on chlorine degradation, HAA formation, and HAA speciation under controlled experimental conditions. Chlorine decay and HAA formation were significantly enhanced in the presence of copper with the extent of copper catalysis being affected by the solution pH and the concentration of copper corrosion products. Accelerated chlorine decay and increased HAA formation were observed at pH 8.6 in the presence of 1.0 mg/L Cu(II) compared with that observed at pH 6.6 and pH 7.6. Further investigation of chlorine decay in the presence of both Suwannee River NOM and Cu(II) indicated that an increased reactivity of NOM with dissolved and/or solid surface-associated Cu(II), rather than chlorine auto-decomposition, was a primary reason for the observed rapid chlorine decay. Copper corrosion solids [Cu(2)O, CuO, Cu(2)(OH)(2)CO(3)] exhibited catalytic effects on both chlorine decay and HAA formation. Contrary to the results observed when in the absence of copper corrosion products, DCAA formation was consistently predominant over other HAA species in the presence of copper corrosion products, especially at neutral and high pH. This study improves the understanding for water utilities and households regarding chlorine residuals and HAA concentrations in distribution systems, in particular once the water reaches domestic plumbing where copper is widely used. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Factors affecting THMs, HAAs and HNMs formation of Jin Lan Reservoir water exposed to chlorine and monochloramine.

    Science.gov (United States)

    Hong, Huachang; Xiong, Yujing; Ruan, Mengyong; Liao, Fanglei; Lin, Hongjun; Liang, Yan

    2013-02-01

    The formations of THMs, HAAs, and HNMs from chlorination and chloramination of water from Jinlan Reservoir were investigated in this study. Results showed that monochloramine rather than chlorine generally resulted in lower concentration of DBPs, and the DBPs formation varied greatly as the treatment conditions changed. Specifically, the yields of THMs, HAAs and HNMs all increased with the high bromide level and high disinfectant dose both during chlorination and chloramination. The longer reaction time had a positive effect on the formation of THMs, HAAs and HNMs during chlorination and HNMs during chloramination. However, no time effect was observed on the formation of THMs and HAAs during chloramination. An increase in pH enhanced the levels of THMs and HNMs upon chlorination but reduced levels of HNMs upon chloramination. As for the THMs in chloramination and HAAs in chlorination and chloramination, no obvious pH effect was observed. The elevated temperature significantly increased the yields of THMs during chlorination and HNMs during chloramination, but has no effect on THMs and HAAs yields during chloramination. In the same temperature range, the formation of HAAs and HNMs in chlorination showed a first increasing and then a decreasing trend. In chloramination study, addition of nitrite markedly increased the formation of HNMs but had little impact on the formation of THMs and HAAs. While in chlorination study, the presence of high nitrite levels significantly reduced the yields of THMs, HAAs and HNMs. Range analysis revealed that the bromide and disinfectant levels were the major factors affecting THMs, HAAs and HNMs formation, in both chlorination and chloramination. Finally, comparisons of the speciation of mono-halogenated, di-halogenated, tri-halogenated HAAs and HNMs between chlorination and monochloramination were also conducted, and factors influencing the speciation pattern were identified. Copyright © 2012 Elsevier B.V. All rights reserved.

  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. Biogeochemical cycles of chlorine in the coniferous forest ecosystem: practical implications

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Clarke, N.; Lachmanová, Z.; Forczek, Sándor; Fuksová, Květa; Gryndler, Milan

    2010-01-01

    Roč. 56, č. 8 (2010), s. 357-367 ISSN 1214-1178 R&D Projects: GA MŠk 7F09026 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : chlorine cycle * chlorination * enzymatic Subject RIV: GK - Forestry Impact factor: 1.076, year: 2010 www.agriculturejournals.cz/publishedArticle?journal=PSE&volume=56&firstPage=357

  9. Biological Chlorine Cycling in Arctic Peat Soils

    Science.gov (United States)

    Zlamal, J. E.; Raab, T. K.; Lipson, D.

    2014-12-01

    Soils of the Arctic tundra near Barrow, Alaska are waterlogged and anoxic throughout most of the profile due to underlying permafrost. Microbial communities in these soils are adapted for the dominant anaerobic conditions and are capable of a surprising diversity of metabolic pathways. Anaerobic respiration in this environment warrants further study, particularly in the realm of electron cycling involving chlorine, which preliminary data suggest may play an important role in arctic anaerobic soil respiration. For decades, Cl was rarely studied outside of the context of solvent-contaminated sites due to the widely held belief that it is an inert element. However, Cl has increasingly become recognized as a metabolic player in microbial communities and soil cycling processes. Organic chlorinated compounds (Clorg) can be made by various organisms and used metabolically by others, such as serving as electron acceptors for microbes performing organohalide respiration. Sequencing our arctic soil samples has uncovered multiple genera of microorganisms capable of participating in many Cl-cycling processes including organohalide respiration, chlorinated hydrocarbon degradation, and perchlorate reduction. Metagenomic analysis of these soils has revealed genes for key enzymes of Cl-related metabolic processes such as dehalogenases and haloperoxidases, and close matches to genomes of known organohalide respiring microorganisms from the Dehalococcoides, Dechloromonas, Carboxydothermus, and Anaeromyxobacter genera. A TOX-100 Chlorine Analyzer was used to quantify total Cl in arctic soils, and these data were examined further to separate levels of inorganic Cl compounds and Clorg. Levels of Clorg increased with soil organic matter content, although total Cl levels lack this trend. X-ray Absorption Near Edge Structure (XANES) was used to provide information on the structure of Clorg in arctic soils, showing great diversity with Cl bound to both aromatic and alkyl groups

  10. 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.

  11. 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.

  12. 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...

  13. Analyzing Environmental Policies for Chlorinated Solvents with a Model of Markets and Regulations

    Science.gov (United States)

    1991-01-01

    chlorine, fluorine , bromine, and iodine. Another broad term is chlorocarbons (fluorocarbons), which indicates the chlorinated ( fluorinated ) hydrocarbons... varnishes , and lacquers (Wolf, Yazdani, and Yates, 1990b). Process Substitutes. The only process modifications that are available for consumer paint

  14. 21 CFR 177.1610 - Polyethylene, chlorinated.

    Science.gov (United States)

    2010-04-01

    ... Chlorine in Vinyl Chloride Polymers and Copolymers,” which is incorporated by reference (Copies may be..., Philadelphia, PA 19428-2959, or may be examined at the National Archives and Records Administration (NARA). For... percent in plastic articles prepared from polyvinyl chloride and/or from vinyl chloride copolymers...

  15. 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.

  16. Effects of chain length, chlorination degree, and structure on the octanol-water partition coefficients of polychlorinated n-alkanes.

    Science.gov (United States)

    Hilger, Bettina; Fromme, Hermann; Völkel, Wolfgang; Coelhan, Mehmet

    2011-04-01

    Log octanol-water partition coefficients (log Kow) of 40 synthesized polychlorinated n-alkanes (PCAs) with different chlorination degrees were determined using reversed-phase high performance liquid chromatography (RP-HPLC). In addition, log Kow values of a technical mixture namely Cereclor 63L as well as 15 individual in house synthesized C10, C11, and C12 chloroalkanes with known chlorine positions were estimated. Based on these results, the effects of chain length, chlorination degree, and structure were explored. The estimated log Kow values ranged from 4.10 (polychlorinated n-decanes with 50.2% chlorine content) to 11.34 (polychlorinated n-octacosanes with 54.8% chlorine content) for PCAs and from 3.82 (1,2,5,6,9,10-hexachlorodecane) to 7.75 (1,1,1,3,9,11,11,11-octachlorododecane) for the individual chloroalkanes studied. The results showed that log Kow value was influenced linearly at a given chlorine content by chain length, while a polynominal effect was observed in dependence on the chlorination degree of an alkane chain. Chlorine substitution pattern influenced markedly the log Kow value of chloroalkanes.

  17. The chlorine-36 dating program at the Australian National University

    International Nuclear Information System (INIS)

    Fifield, L.F.; Ophel, T.R.; Bird, J.R.; Calf, G.E.; Allison, G.B.; Chivas, A.R.

    1987-05-01

    A chlorine-36 dating capability based on the 14UD pelletron accelerator was developed at the Australian National University during 1986 and is now entering the routine measurement phase. It involves a collaboration between the Department of Nuclear Physics, the Australian Atomic Energy Commission and CSIRO Division of Soils. The chlorine-36 dating system is described and some early results are presented for samples of chloride from salt lakes in Western Australia and soil profiles in South Australia

  18. Formation of brominated trihalomethanes in chlorinated drinking-water from Lake Constance

    International Nuclear Information System (INIS)

    Petri, M.; Stabel, H.H.

    1994-01-01

    The formation of trihalomethanes (THMs) in raw water and drinking water from Lake Constance containing low amounts of DOC and bromide was studied with special emphasis on brominated trihalomethanes (Br-THMs). If the raw water was ozonated prior to chlorination, the formation of THMs was reduced by 37%, and if a rapid sandfiltration was interposed, the THM-formation was again slightly enhanced. The percentage of Br-THMs on total-THMs increased from 16% to 35% during the treatment process. In the drinking water distribution system of BWV the formation of Br-THMs and CHCl 3 was studied with respect to residence time and post-chlorination. Unless the post-chlorination was performed, the THM-formation in the distribution system resembled that obtained from laboratory studies, except for small amounts of THMs being purged due to transport in the mains and residence in the reservoirs. Post-chlorination increased CHCl 3 - and the CHBrCl 2 -formation, but there was no effect on the formation of CHBr 2 Cl and CHBr 3 . However, the total THM-concentration in the drinking water never exceeded the German drinking water standard of 10 μg/L. (orig.) [de

  19. Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater.

    Science.gov (United States)

    Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

    2015-12-01

    Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP) of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1 st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing. Copyright © 2015. Published by Elsevier B.V.

  20. Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater

    Directory of Open Access Journals (Sweden)

    Guoo-Shyng Wang Hsu

    2015-12-01

    Full Text Available Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing.