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Sample records for chlorine 35 reactions

  1. Neutron-activated determination of chlorine, using the 35Cl(n,p)35S reaction as the basis, in thin coatings of silicon dioxide

    International Nuclear Information System (INIS)

    The neutron-activation determination of chlorine in thin coatings of silicon dioxide on silicon has been shown to be possible through the use of the 55Cl(n, P)35S reaction. The detection limit of chlorine is 3 x 10-9 g (5 x 1013 atoms)

  2. Reaction products of chlorine dioxide.

    OpenAIRE

    Stevens, A A

    1982-01-01

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

  3. 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.

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

    OpenAIRE

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

    1986-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-11-01

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

  7. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO2 with ubiquitous amino acids present in natural waters.

  8. Stepwise Chlorination-Chemical Vapor Transport Reactions for Bastnaesite Concentrate

    Institute of Scientific and Technical Information of China (English)

    张丽清; 王军; 范世华; 雷鹏翔; 王之昌

    2002-01-01

    Vapor phase extraction and mutual separation of rare earth (RE) elements from bastnaesite concentrate were investigated using stepwise chlorination-chemical vapor transport reactions mediated by vapor complexes LnAlnCl3n+3 (Ln=RE elements). The bastnaesite was heated to 800 K and chlorinated between 800~1300 K with C+Cl2+SiCl4 to remove CO2, SiF4 and high volatile chlorides. At the temperature of 1300 K for 6 h, the resulted RE chlorides were chemically transported and mutual separated with the vapor complexes while CaCl2 and BaCl2 were remained in the residues. Significantly different CVT characteristics were observed for gradually decreased and wave form temperature gradients

  9. Physical chemistry of the chlorination reactions of metals and alloys

    International Nuclear Information System (INIS)

    This thesis has contributed towards the knowledge of complex systems.The chlorination reactions are non-catalytic solid-gas heterogeneous reactions which, in addition to the difficulties associated with the reactions occurring in an interface, have the particular features of chlorides compounds and their interactions.The questions arising from this type of study can not be solved by the application of an individual analysis technique.From the experimental point of view it is complicated, and many instrumental techniques need to be applied in order to obtain significant results as well as meaningful interpretations.The system under study is the chlorination of ternary and binary alloys containing Al, Cu and Zn and the pure metals, as these elements belong to the spent nuclear fuel cladding.The aim of the research has been to develop a process that eliminates most of the aluminium, which is the more abundant specie. In this way, the amount of material to be conditioned (vitrified) is reduced.The objectives proposed for each system have been achieved, and the results obtained can also be applied to similar systems for metal recycling

  10. Some kinetics aspects of chlorine-solids reactions

    Directory of Open Access Journals (Sweden)

    Kanari, N.

    2010-02-01

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

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

  11. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    International Nuclear Information System (INIS)

    Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be used for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of

  12. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    Energy Technology Data Exchange (ETDEWEB)

    McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

    2003-12-11

    Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be used for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  14. Degradation characteristics of metoprolol during UV/chlorination reaction and a factorial design optimization.

    Science.gov (United States)

    Nam, Seung-Woo; Yoon, Yeomin; Choi, Dae-Jin; Zoh, Kyung-Duk

    2015-03-21

    Metoprolol (MTP), a hypertension depressor, has been increasingly detected even after conventional water treatment processes. In this study, the removal of MTP was compared using chlorination (Cl2), UV-C photolysis, and UV/chlorination (Cl2/UV) reactions. The results showed that the UV/chlorination reaction was most effective for MTP removal. MTP removal during UV/chlorination reaction was optimized under various conditions of UV intensity (1.1-4.4 mW/cm(2)), chlorine dose (1-5 mg/L as Cl2), pH (2-9), and dissolved organic matter (DOM, 1-4 mgC/L) using a two-level factorial design with 16 experimental combinations of the four factors. Among the factors examined, DOM scavenging by OH radicals was the most dominant in terms of MTP removal during UV/chlorination reaction. The established model fit well with the experimental results using to various water samples including surface waters, filtered and tap water samples. The optimized conditions (UV intensity=4.4 mW/cm(2), [Cl2]=5 mg/L, pH 7, and [DOM]=0.8-1.1 mgC/L) of the model removed more than 78.9% of MTP for filtered water samples during UV/chlorination reaction. Using LC-MS/MS, five byproducts of MTP (molecular weight: 171, 211, 309, 313, and 341, respectively) were identified during UV/chlorination reaction. Based on this information, the MTP transformation mechanism during UV/chlorination was suggested. Our results imply that applying UV/chlorination process after filtration stage in the water treatment plant (WTP) would be the most appropriate for effective removal of MTP.

  15. Ion Chromatographic Method with Post-Column Fuchsin Reaction for Measurement of Bromate in Chlorinated Water

    Directory of Open Access Journals (Sweden)

    Homer C. Genuino

    2009-06-01

    Full Text Available An ion chromatographic method that employs a post-column reaction with fuchsin and spectrophotometric detection was optimized for measuring bromate (BrO3- in water. BrO3- is converted to Br2 by sodium metabisulfite and then reacted with acidic fuchsin to form a red-colored product that strongly absorbs at 530 nm. The reaction of BrO3- and fuchsin reagent is optimum at pH 3.5 and 65 oC. The method has a limit of quantitation of 4.5 µg L-1 and is linear up to 150 µg L-1 BrO3-. Recoveries from spiked samples were high ranging from 95 to 102 % using external standard calibration and 87 to 103 % using standard addition method. Intra-batch and inter-batch reproducibility studies of the method resulted to RSD values ranging from 0.62 to 2.01 % and percent relative error of 0.12 to 2.94 % for BrO3- concentrations of 10 µg L-1 and 50 µg L-1. This method is free of interferences from common inorganic anions at levels typically found in chlorinated tap drinking water without preconcentration. The optimized method can be applied to trace analysis of bromate in chlorinated tap drinking water samples.

  16. Chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Talmage, Sylvia Smith [ORNL

    2009-01-01

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

  17. Reactions of chlorine (III) and their kinetics in the chlorine dioxide bleaching of kraft pulps

    OpenAIRE

    Lehtimaa, Tuula

    2010-01-01

    The reactions of Cl(III) were investigated utilizing iodometric titration in combination with DMSO and EDTA to prevent undesired side reactions. Among a large group of suggested Cl(III) decomposition reactions, two reactions were found to be adequate to describe the Cl(III) decomposition in the absence of metals and HOCl. The rate parameters (k - rate coefficient, Ea - activation energy) were determined for these reactions. The reaction between Cl(III) and HOCl is known to start with the...

  18. Reaction products from the chlorination of seawater. Final report 15 Jul 75-14 Jul 80

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.H.; Smith, C.A.; Zika, R.G.

    1981-03-01

    Chemical treatment of natural waters, in particular the use of chlorine as a biocide, modifies the chemistry of these waters in ways that are not fully understood. The research described in this report examined both inorganic and organic reaction products from the chlorination of seawater using a variety of analytical approaches. Some analytical methods in widespread current use underestimate the residual oxidants in chlorinated seawater by as much as 70% depending upon the detail of the procedures. The chlorination of seawater in the presence of light produces substantial quantities of bromate ions which can influence standard analytical procedures and represents an unknown factor in estuarine and coastal waters. The copper complexing capacity of Biscayne Bay, Florida water was found to be substantially reduced with the addition of chlorine. Analysis was made by anodic stripping voltammetry on water samples after successive additions of copper sulfate solution. Laboratory chlorination of water from the intake of the Port Everglades, Florida power plant produces bromoform levels comparable to that found in the plant discharge. These results are in contrast to results reported in the literature for a power plant on the Patuxent estuary in Maryland, so that bromoform production appears to be site-specific. Chloroform extracts of chlorinated Biscayne Bay water are found to contain halogenated compounds which are new and different, and which pose unusual analytical problems. Studies using GC/ECD, GC/MS, HPLC, H NMR, differential pulsed polarography and other techniques on natural extracts and synthesized compounds are reported.

  19. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection.

    Science.gov (United States)

    Chusaksri, Sarinma; Sutthivaiyakit, Somyote; Sedlak, David L; Sutthivaiyakit, Pakawadee

    2012-03-30

    Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3'-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25°C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M(-1)s(-1) for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

  20. Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography–mass spectrometry

    OpenAIRE

    JUN WANG; DINGQIANG LU; XIUQUAN LING; SHUMIN ZHANG; MINGXIN LIANG; PINGKAI OUYANG; JIANHUI CHEN; WEI REN

    2010-01-01

    As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on...

  1. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection

    International Nuclear Information System (INIS)

    Highlights: ► Mechanism of chlorine reaction with phenylurea compounds has been studied. ► It depends on both chlorinating species and substitutents on the compounds. ► Main products were identified using LC–MS/MS and authentic standards. ► Their transformation under normal drinking water disinfection was predicted. - Abstract: Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3′-N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25 °C and pH 7 were 0.76 ± 0.16, 0.52 ± 0.11, 0.39 ± 0.02, 0.27 ± 0.04 and 0.23 ± 0.05 M−1 s−1 for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be incomplete.

  2. Reactions of phenylurea compounds with aqueous chlorine: Implications for herbicide transformation during drinking water disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Chusaksri, Sarinma [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand); Sutthivaiyakit, Somyote [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Bangkok 10240 (Thailand); Sedlak, David L., E-mail: sedlak@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Sutthivaiyakit, Pakawadee, E-mail: fscipws@ku.ac.th [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Kasetsart, Bangkok 10900 (Thailand)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Mechanism of chlorine reaction with phenylurea compounds has been studied. Black-Right-Pointing-Pointer It depends on both chlorinating species and substitutents on the compounds. Black-Right-Pointing-Pointer Main products were identified using LC-MS/MS and authentic standards. Black-Right-Pointing-Pointer Their transformation under normal drinking water disinfection was predicted. - Abstract: Phenylurea herbicides have been known to contaminate surface waters serving as potable supplies. To access the potential for transformation of these compounds during drinking water treatment, reactions of phenylurea compounds with aqueous chlorine at different pHs were investigated. The effect of substitution at the amino-N on the rate of transformation depends upon pH. Under acidic conditions, all of the phenylurea studied except 3,4-dichloro-3 Prime -N-methylphenylurea (3,4-DCMPU) exhibited third-order kinetics, second order with respect to chlorine and first order with respect to phenylurea, while the reactions of 3,4-DCMPU were first order with respect to both chlorine and the organic compound. Under neutral and alkaline conditions, all compounds exhibited second-order kinetics that was first order with respect to chlorine and the organic compound. Apparent second-order rate constants at 25 Degree-Sign C and pH 7 were 0.76 {+-} 0.16, 0.52 {+-} 0.11, 0.39 {+-} 0.02, 0.27 {+-} 0.04 and 0.23 {+-} 0.05 M{sup -1} s{sup -1} for phenylurea, 3, 4-dichlorophenylurea, 3, 4-DCMPU, metoxuron and monuron, respectively. Studies of the chlorination products, monitored by LC/MS/MS, under different pH values indicated the reaction to take place at both N atoms and also at ortho- and para- positions of the phenylurea aromatic group. The main chlorinating species were found to be different in different pH ranges. Under conditions typically encountered in drinking water treatment systems, transformation of these compounds by chlorine will be

  3. Cluster reaction of [Ag8]-/[Cu8]- with chlorine: Evidence for the harpoon mechanism?

    Science.gov (United States)

    Luo, Zhixun; Berkdemir, Cüneyt; Smith, Jordan C.; Castleman, A. W.

    2013-09-01

    To examine the question whether the harpoon mechanism can account for the reactive behavior of microscopic charged systems, we have investigated the reactivity of coinage metal clusters in gas phase. Our studies reveal that the reactivity between [Cu8]-/[Ag8]- and chlorine gas is consistent with the harpoon mechanism. An increased reactive cross section is noted through our theoretical estimation based on two methods, ascribed to a long-range transfer of valence electrons from the [Cu8]-/[Ag8]- cluster to chlorine. Insights into this reactivity will be of interest to other researchers working on obtaining a better understanding of the reaction mechanisms of such superatomic species.

  4. Experimental evidence of localized oscillations in the photosensitive chlorine dioxide-iodine-malonic acid reaction

    OpenAIRE

    Mínguez, David G.; Alonso Muñoz, Sergio; Muñuzuri, A. P.; Sagués i Mestre, Francesc

    2006-01-01

    The interaction between Hopf and Turing modes has been the subject of active research in recent years. We present here experimental evidence of the existence of mixed Turing-Hopf modes in a two-dimensional system. Using the photosensitive chlorine dioxide-iodine-malonic acid reaction (CDIMA) and external constant background illumination as a control parameter, standing spots oscillating in amplitude and with hexagonal ordering were observed. Numerical simulations in the Lengyel-Epstein model ...

  5. Literature information applicable to the reaction of uranium oxides with chlorine to prepare uranium tetrachloride

    International Nuclear Information System (INIS)

    The reaction of uranium oxides and chlorine to prepare anhydrous uranium tetrachloride (UCl4) are important to more economical preparation of uranium metal. The most practical reactions require carbon or carbon monoxide (CO) to give CO or carbon dioxide (CO2) as waste gases. The chemistry of U-O-Cl compounds is very complex with valances of 3, 4, 5, and 6 and with stable oxychlorides. Literature was reviewed to collect thermochemical data, phase equilibrium information, and results of experimental studies. Calculations using thermodynamic data can identify the probable reactions, but the results are uncertain. All the U-O-Cl compounds have large free energies of formation and the calculations give uncertain small differences of large numbers. The phase diagram for UCl4-UO2 shows a reaction to form uranium oxychloride (UOCl2) that has a good solubility in molten UCl4. This appears more favorable to good rates of reaction than reaction of solids and gases. There is limited information on U-O-Cl salt properties. Information on the preparation of titanium, zirconium, silicon, and thorium tetrachlorides (TiCl4, ZrCl4, SiCl4, ThCl4) by reaction of oxides with chlorine (Cl2) and carbon has application to the preparation of UCl4

  6. EFFECT OF FLUORINE AND CHLORINE IONS ON THE REACTION SINTERING OF MECHANICALLY ACTIVATED ZIRCON-ALUMINA MIXTURE

    Directory of Open Access Journals (Sweden)

    R. Zamani Foroshani

    2015-09-01

    Full Text Available The aim of this work was to study the effect of fluorine and chlorine ions on the formation of mullite during the reaction sintering of mechanically activated zircon-alumina powder mixture. The results showed that mechanical activation of zirconalumina powder mixture for 20 h led to grain refinement and partial amorphization. In the presence of fluorine and chlorine ions, complete formation of mullite in the mechanically activated sample occurred after 2 h of reaction sintering at 1300oC and 1400oC, respectively. In the sample lacking fluorine and chlorine ions, mullitization was not completed even after 2 h of reaction sintering at 1400oC. It was concluded that presence of fluorine and chlorine ions enhance the dissociation of zircon and formation of mullite during the reaction sintering of mechanically activated zircon-alumina mixture.

  7. Reactions of chlorine nitrate with HCl and H2O. [ozone controlling chemistry in stratosphere

    Science.gov (United States)

    Hatakeyama, Shiro; Leu, Ming-Taun

    1986-01-01

    The kinetics of the reactions of chlorine nitrate with HCl and H2O are characterized using a static photolysis/Fourier transform infrared spectrophotometer apparatus. For the homogeneous gas-phase reaction with HCl, an upper limit for the rate constant of less than 8.4 x 10 to the -21st, and for the reaction with H2O, a limit of less than 3.4 x 10 to the -21st cu cm/molecule per s, were obtained at 296 + or - 2 K. The yield of HNO3 is almost unity in both cases, and no synergistic effect is noted between HCl and H2O. The kinetic behavior of the reaction with H2O is well described by simple first-order kinetics, while the behavior of the reaction with HCl is described in terms of the Langmuir adsorption isotherm.

  8. Ground State Reactions of nC60 with Free Chlorine in Water.

    Science.gov (United States)

    Wu, Jiewei; Benoit, Denise; Lee, Seung Soo; Li, Wenlu; Fortner, John D

    2016-01-19

    Facile, photoenhanced transformations of water-stable C60 aggregates (nC60) to oxidized, soluble fullerene derivatives, have been described as key processes in understanding the ultimate environmental fate of fullerene based materials. In contrast, fewer studies have evaluated the aqueous reactivity of nC60 during ground-state conditions (i.e., dark conditions). Herein, this study identifies and characterizes the physicochemical transformations of C60 (as nC60 suspensions) in the presence of free chlorine, a globally used chemical oxidant, in the absence of light under environmentally relevant conditions. Results show that nC60 undergoes significant oxidation in the presence of free chlorine and the oxidation reaction rates increase with free chlorine concentration while being inversely related to solution pH. Product characterization by FTIR, XPS, Raman Spectroscopy, TEM, XRD, TOC, collectively demonstrates that oxidized C60 derivatives are readily formed in the presence of free chlorine with extensive covalent oxygen and even chlorine additions, and behave as soft (or loose) clusters in solution. Aggregation kinetics, as a function of pH and ionic strength/type, show a significant increase in product stabilities for all cases evaluated, even at pH values approaching 1. As expected with increased (surface) oxidation, classic Kow partitioning studies indicate that product clusters are relatively more hydrophilic than parent (reactant) nC60. Taken together, this work highlights the importance of understanding nanomaterial reactivity and the identification of corresponding stable daughter products, which are likely to differ significantly from parent material properties and behaviors.

  9. A coupled chemical burster: The chlorine dioxide-iodide reaction in two flow reactors

    Science.gov (United States)

    Dolnik, Milos; Epstein, Irving R.

    1993-01-01

    The dynamical behavior of the chlorine dioxide-iodide reaction has been studied in a system consisting of two continuous flow stirred tank reactors (CSTRs). The reactors are coupled by computer monitoring of the electrochemical potential in each reactor, which is then used to control the input into the other reactor. Two forms of coupling are employed: reciprocally triggered, exponentially decreasing stimulation, and alternating mass exchange. The reaction, which exhibits oscillatory and excitable behavior in a single CSTR, displays neuronlike bursting behavior with both forms of coupling. Reciprocal stimulation yields bursting in both reactors, while with alternating mass exchange, bursting is observed in one reactor and complex oscillation in the other. A simple model of the reaction gives good agreement between the experimental observations and numerical simulations.

  10. Chlorine Dioxide-Iodide-Methyl Acetoacetate Oscillation Reaction Investigated by UV-Vis and Online FTIR Spectrophotometric Method

    OpenAIRE

    Laishun Shi; Xiaomei Wang; Na Li; Jie Liu; Chunying Yan

    2012-01-01

    In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide-iodide ion-methyl acetoacetate reaction system, a series of experiments were done by using UV-Vis and online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at wavelength of 289 nm. There is a preoscillatory or induction period, and the amplitude and...

  11. Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography–mass spectrometry

    Directory of Open Access Journals (Sweden)

    JUN WANG

    2010-01-01

    Full Text Available As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on the results the kinetic mechanism of the reaction was investigated. The structure of main products, including 1,3--dichloropropan-2-ol, 2,3-dichloropropan-1-ol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol and glycerol was ascertained by gas chromatography–mass spectrometry and the isomers of the products were distinguished. Apidic acid was considered as the best catalyst because of its excellent catalytic effect and high boiling point. The mechanism of the glycerol chlorination reaction was proposed and a new kinetic model was developed. Kinetic equations of the process in the experimental range were obtained by data fitting and the activation energies of each tandem reaction were 30.7, 41.8, 29.4 and 49.5 kJ mol-1, respectively. This study revealed the process and mechanism of the kinetics and provides the theoretical basis for engineering problems.

  12. Heterogeneous chemical reaction of chlorine nitrate and water on sulfuric-acid surfaces at room temperature

    Science.gov (United States)

    Rossi, Michel J.; Malhotra, Ripudaman; Golden, David M.

    1987-01-01

    The use of H2SO4 as a catalyst for aerosol production of chlorine compounds in the chemistry of the antarctic stratosphere was investigated in laboratory trials. The experiments involved the gas surface collision rate of a molecule on a given surface during its residence time in a Knudsen cell in molecular flow conditions. Chlorine nitrate gas was made to flow through a chamber exposed to a container holding a 95.6 pct H2SO4 solution. Gas leaving the cell was scanned with a mass spectrometer. A sticking coefficient of 0.00032 was found for the chlorine nitrate, a value five times that previously reported.

  13. Chlorine Dioxide-Iodide-Methyl Acetoacetate Oscillation Reaction Investigated by UV-Vis and Online FTIR Spectrophotometric Method

    Directory of Open Access Journals (Sweden)

    Laishun Shi

    2012-01-01

    Full Text Available In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide-iodide ion-methyl acetoacetate reaction system, a series of experiments were done by using UV-Vis and online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at wavelength of 289 nm. There is a preoscillatory or induction period, and the amplitude and the number of oscillations are associated with the initial concentration of reactants. The equations for the triiodide ion reaction rate changing with reaction time and the initial concentrations in the oscillation stage were obtained. Oscillation reaction can be accelerated by increasing temperature. The apparent activation energies in terms of the induction period and the oscillation period were 26.02 KJ/mol and 17.65 KJ/mol, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism was proposed for the oscillation reaction.

  14. Interactively interfacial reaction of iron-reducing bacterium and goethite for reductive dechlorination of chlorinated organic compounds

    Institute of Scientific and Technical Information of China (English)

    LI XiaoMin; LI YongTao; LI FangBai; ZHOU ShunGui; FENG ChunHua; LIU TongXu

    2009-01-01

    The interactively interfacial reactions between the iron-reducing bacterium (Shewanella decolorationis,S12) and iron oxide (α-FeOOH) were investigated to determine reductive dechlorination transformation of chlorinated organic compounds (chloroform and pentachlorophenol).The results showed that the interactive system of S12+ α-FeOOH exhibited relatively high dechlorination rate.By comparison,the S12 biotic system alone had no obvious dechlorination,and the α-FeOOH abiotic system showed low dechlorination rate.The enhanced dechlorination of chloroform and pentachlorophenol in the interactive system of S12+α-FeOOH was derived from the promoted generation of adsorbed Fe(Ⅱ) by S12.A decrease in redox potential of the Fe (Ⅲ)/Fe (Ⅱ) couple in the interactive reaction system was determined by cyclic voltammetry.Our results will give new insight into interactively interfacial reaction between iron-reducing bacterium and iron oxides for degradation of chlorinated organic compounds under anaerobic condition.

  15. Investigation of Unexpected Reaction Intermediates in the Alkaline Hydrolysis of Methyl 3,5-Dinitrobenzoate

    Science.gov (United States)

    Silva, Clesia C.; Silva, Ricardo O.; Navarro, Daniela M. A. F.; Navarro, Marcelo

    2009-01-01

    An experimental project aimed at identifying stable reaction intermediates is described. Initially, the studied reaction appears to involve the simple hydrolysis, by aqueous sodium hydroxide, of methyl 3,5-dinitrobenzoate dissolved in dimethyl sulfoxide. On mixing the substrates, however, the reaction mixture unexpectedly turns an intense red in…

  16. Experimental Study of Closed System in the Chlorine Dioxide-Iodide-Sulfuric Acid Reaction by UV-Vis Spectrophotometric Method

    Directory of Open Access Journals (Sweden)

    Na Li

    2011-01-01

    Full Text Available The mole ratio r(r=[I−]0/[ClO2]0 has great influence on ClO2-I−-H2SO4 closed reaction system. By changing the initiate concentration of potassium iodide, the curve of absorbance along with the reaction time was obtained at 350 nm and 297 nm for triiodide ion, and 460 nm for iodine. The changing point of the absorbance curve's shape locates at r=6.00. For the reaction of ClO2-I− in the absence of H2SO4, the curve of absorbance along with the reaction time can be obtained at 350 nm for triiodide ion, 460 nm for iodine. The mole ratio r is equal to 1.00 is the changing point of the curve's shape no matter at which wavelength to determine the reaction. For the reaction of ClO2-I−-H+ in different pH buffer solution, the curve of absorbance along with the reaction time was recorded at 460 nm for iodine. When r is greater than 1.00, the transition point of the curve's shape locates at pH 2.0, which is also the point of producing chlorite or chloride for chlorine dioxide at different pH. When r is less than 1.00, the transition point locates at pH 7.0.

  17. Temperature dependence and mechanism of the reaction between O(3P) and chlorine dioxide

    Science.gov (United States)

    Colussi, A. J.; Sander, S. P.; Fiedl, R. R.

    1992-01-01

    Second-order rate constants for the decay of O(3P) in excess chlorine dioxide, k(II), were measured as a function of total pressure (20-600 Torr argon) and temperature (248-312 K), using flash photolysis-atomic resonance fluorescence. Results indicate that k(II) is pressure dependent with a value, K(b), that is nonzero at zero pressure, and both the third-order rate constant and k(b) have negative temperature dependences.

  18. Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts--Electrophilic aromatic substitution and oxidation.

    Science.gov (United States)

    Criquet, Justine; Rodriguez, Eva M; Allard, Sebastien; Wellauer, Sven; Salhi, Elisabeth; Joll, Cynthia A; von Gunten, Urs

    2015-11-15

    Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, species-specific and/or apparent second order rate constants and mechanisms for the reactions of bromine and chlorine have been determined for various phenolic compounds (phenol, resorcinol, catechol, hydroquinone, phloroglucinol, bisphenol A, p-hydroxybenzoic acid, gallic acid, hesperetin and tannic acid) and flavone. The reactivity of bromine with phenolic compounds is very high, with apparent second order rate constants at pH 7 in the range of 10(4) to 10(7) M(-1) s(-1). The highest value was recorded for the reaction between HOBr and the fully deprotonated resorcinol (k = 2.1 × 10(9) M(-1) s(-1)). The reactivity of phenolic compounds is enhanced by the activating character of the phenolic substituents, e.g. further hydroxyl groups. With the data set from this study, the ratio between the species-specific rate constants for the reactions of chlorine versus bromine with phenolic compounds was confirmed to be about 3000. Phenolic compounds react with bromine or chlorine either by oxidation (electron transfer, ET) or electrophilic aromatic substitution (EAS) processes. The dominant process mainly depends on the relative position of the hydroxyl substituents and the possibility of quinone formation. While phenol, p-hydroxybenzoic acid and bisphenol A undergo EAS, hydroquinone, catechol, gallic acid and tannic acid, with hydroxyl substituents in ortho or para positions, react with bromine by ET leading to quantitative formation of the corresponding quinones. Some compounds (e.g. phloroglucinol) show both partial oxidation and partial electrophilic aromatic substitution and the ratio observed for the pathways depends on the pH. For the reaction of six NOM extracts with bromine, electrophilic aromatic substitution

  19. Influence of hydrogen fluoride on kinetics of thermal reaction of hydrogen with chlorine monofluoride

    Energy Technology Data Exchange (ETDEWEB)

    Zhitneva, G.P.

    1986-07-01

    The influence of HF on the kinetics of the thermal reaction of H/sub 2/ with ClF in a fused quartz vessel was studied. It was shown that HF inbibits the reaction by blocking the reaction centers on the vessel surface, which lowers the rate of the heterogeneous generation of chains.

  20. Ab initio Mechanism Study on the Reaction of Chlorine Atom with Formic Acid

    Institute of Scientific and Technical Information of China (English)

    于海涛; 付宏刚; 等

    2003-01-01

    The potential energy surface(PES) for the reaction of Cl atom with HCOOH is predicted using ab initio molecular orbital calculation methods at UQCIDS(T,full)6-311++G(3df,2p)//UMP2(full)/6-311+G(d,P) level of theory with zero-point vibrational energy (ZPVE) correction.The calculated results show that the reaction mechanism of Cl atom with formic acid is a C-site hydrogen abstraction reaction from cis-HOC(H)O molecule by Cl atom with a 3.73kJ/mol reaction barrier height,leading to the formation of cis-HOCO radical which will reacts with Cl atom or other molecules in such a reaction system.Because the reaction barrier height of O-site hydrogen abstraction reaction from cis-HOC(H)O molecule by Cl atom which leads to the formation of HCO2 radical is 67.95kJ/mol,it is a secondary reaction channel in experiment,This is in good agreement with the prediction based on the previous experiments.

  1. Nuclear quadrupole resonance 35Cl in the complexes of the 5 group element pentafluorides with trifluoride and pentafluoride of chlorine

    International Nuclear Information System (INIS)

    The following complexes are investigated on 35Cl at 77 K by the NQR method: ClF5xnSbF5 (n=1, 2, 4), ClF5xTaF5, ClF3xnSbF5 (n=1, 2, 4), ClF3xMF5 (M=As,Nb,Ta), ClF5 and CsClF4. The order of the increase of the MF5 acseptor ability is established according the 35Cl NQR spectra. The correlation dependences in ClF3xMF5 complexes are found between ν(35Cl) and the electronegativity difference of F and M, and also between ν(35Cl) and the MF5 formation heats. Calculated are the population of valent 3p-orbitals of chlorium atoms in the ClF3xMF5 complexes, and in ClF3, ClF and CsClF4 as well

  2. Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

    Energy Technology Data Exchange (ETDEWEB)

    Seol, Yongkoo; Javandel, Iraj

    2008-03-15

    Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

  3. Reaction Kinetic Studies of Waste Polymer and Hydrolytic Chlorine in EOCN Production

    Institute of Scientific and Technical Information of China (English)

    Koyo Murakami

    2005-01-01

    @@ 1Results and Discussion EOCNs are widely used by electric and electronics industries and coating and adhesive fields(see Tab. 1 ). EOCNs( =Epoxy O-Cresol Novolac)can be produced commercially in a two-step reaction, which consistsmainly of a novolac reaction step of o-cresol with formalin and an epoxidising step of the the novolac resins with epichlorohydrine in the presence of alkari hydroxide such as caustic soda, byproducing waste polymers which affect adversely fromthe viewpoint of process economy.

  4. Session 6: Catalytic Dechlorination Reaction of Chlorinated Hydrocarbons with Water Using nano-structured Alumina

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Khaleel [United Arab Emirates Univ., Dept. of Chemistry, Al-Ain (United States)

    2004-07-01

    Herein, we report our recent results from a study on the catalytic dechlorination reactions of 1,2-dichloroethane (DCE) and carbon tetrachloride (CTC) with water using HSA-Al{sub 2}O{sub 3} as the catalyst. The obtained experimental results are explained. (O.M.)

  5. Oxidation of elemental mercury by chlorine: Gas phase, Surface, and Photo-induced reaction pathways

    OpenAIRE

    Yan, Nai-Qiang; Liu, Shou-Heng; Chang, Shih-Ger

    2004-01-01

    Accurate oxidation rate constants of mercury gas are needed for determining its dispersion and lifetime in the atmosphere. They would also help in developing a technology for the control of mercury emissions from coal-fired power plants. However, it is difficult to establish the accurate rate constants primarily due to the fact that mercury easily adsorbs on solid surface and its reactions can be catalyzed by the surface. We have demonstrated a procedure that allows the determination of ...

  6. Spectroscopy of $^{35}$P using the one-proton knockout reaction

    CERN Document Server

    Mutschler, A; Lemasson, A; Bazin, D; Borcea, C; Borcea, R; Gade, A; Iwasaki, H; Khan, E; Lepailleur, A; Recchia, F; Roger, T; Rotaru, F; Stanoiu, M; Stroberg, R; Tostevin, J A; Vandebrouck, M; Weisshaar, D; Wimmer, K

    2016-01-01

    The structure of $^{35}$P was studied with a one-proton knockout reaction at88~MeV/u from a $^{36}$S projectile beam at NSCL. The $\\gamma$ rays from thedepopulation of excited states in $^{35}$P were detected with GRETINA, whilethe $^{35}$P nuclei were identified event-by-event in the focal plane of theS800 spectrograph. The level scheme of $^{35}$P was deduced up to 7.5 MeV using$\\gamma-\\gamma$ coincidences. The observed levels were attributed to protonremovals from the $sd$-shell and also from the deeply-bound $p\\_{1/2}$ orbital.The orbital angular momentum of each state was derived from the comparisonbetween experimental and calculated shapes of individual ($\\gamma$-gated)parallel momentum distributions. Despite the use of different reactions andtheir associate models, spectroscopic factors, $C^2S$, derived from the$^{36}$S $(-1p)$ knockout reaction agree with those obtained earlier from$^{36}$S($d$,\

  7. Breakpoint chlorination curves of greywater.

    Science.gov (United States)

    March, J G; Gual, M

    2007-08-01

    A study on chlorination of raw greywater with hypochlorite is reported in this paper. Samples were chlorinated in a variety of conditions, and residual chlorine (Cl2) was measured spectrophotometrically. For each sample, the chlorination curve (chlorine residuals versus chlorine dose) was obtained. Curves showed the typical hump-and-dip profile attributable to the formation and destruction of chloramines. It was observed that, after reactions with strong reductants and chloramines-forming compounds, the remaining organic matter exerted a certain demand of chlorine. The evolution of chlorination curves with addition of ammonia and dodecylbencene sulfonate sodium salt and with dilution of the greywater sample were studied. In addition, chlorination curves at several contact times have been obtained, resulting in slower chlorine decay in the hump zone than in the dip zone. In addition, the decay of coliforms in chlorinated samples was also investigated. It was found that, for a chlorination dosage corresponding to the maximum of the hump zone (average 8.9 mg Cl2/ L), samples were negative in coliforms after 10 to 30 minutes of contact time. After-growth was not observed within 3 days after chlorination. Implications in chlorination treatments of raw greywater can be derived from these results. PMID:17824528

  8. Oxidation of MC-LR and -RR with chlorine and potassium permanganate: toxicity of the reaction products.

    Science.gov (United States)

    Rodríguez, Eva M; Acero, Juan L; Spoof, Lisa; Meriluoto, Jussi

    2008-03-01

    Toxin-producing cyanobacteria are abundant in surface waters used as drinking water resources. Microcystins (MC) produced by certain cyanobacteria present acute and chronic toxicity, and their removal in drinking water treatment processes is of increasing concern. Previous studies have demonstrated that chlorine and potassium permanganate are feasible oxidants for the removal of MCs present in drinking water resources, although the oxidation might lead to toxic oxidation products. In this paper, the toxicity of the oxidation products of MC-LR and -RR has been studied using protein phosphatase 1 inhibition assay (PPIA). The HPLC and ELISA analyses correlated with the PPIA results for both toxins. The samples containing the oxidation products were fractionated by HPLC and the toxicity of the fractions was tested with PPIA. The results revealed that protein phosphatase 1 inhibition emerged only from intact MC, while the oxidation products were non-toxic. Similar results were obtained in experiments performed in natural waters: no reaction products or interactions exhibiting protein phosphatase 1 inhibition were detected.

  9. Dark matter searches going bananas: the contribution of Potassium (and Chlorine) to the 3.5 keV line

    CERN Document Server

    Jeltema, Tesla E

    2014-01-01

    We examine the claimed excess X-ray line emission near 3.5 keV with a new analysis of XMM-Newton observations of the Milky Way center and with a re-analysis of the data on M31 and clusters. In no case do we find conclusive evidence for an excess. We show that known plasma lines, including in particular K XVIII lines at 3.48 and 3.52 keV, provide a satisfactory fit to the XMM data from the Galactic center. We assess the expected flux for the K XVIII lines and find that the measured line flux falls squarely within the predicted range based on the brightness of other well-measured lines in the energy range of interest. We then re-evaluate the evidence for excess emission from clusters of galaxies, including a previously unaccounted for Cl XVII line at 3.51 keV, and allowing for systematic uncertainty in the expected flux from known plasma lines and for additional uncertainty due to potential variation in the abundances of different elements. We find that no conclusive excess line emission is present within the s...

  10. Recent Achievements in the Radiation-Catalysed Chlorination of Chlorinated Pentane Derivatives

    International Nuclear Information System (INIS)

    The radiation-catalysed chlorination of the so-called tetrachloro-cyclopentane, the product obtained from cyclopentadiene by addition of chlorine, has already been studied earlier by the authors with success. On maintaining an adequate dosage rate, no ring cleavage occurs, and, mainly for stereochemical reasons, octachloro-cyclopentene forms as an end product - similarly to conventional chlorination carried out at high temperature (400-500oC), but at substantially lower temperature (170oC) and without any resin formation. It is known that besides other end products, octachloro-cyclopentene forms also from perchlorinated pentane, under simultaneous cyclization. In their recent experiments presented here, the authors investigated how and to what extent the yield of octachloro-cyclopentene is affected by additional chlorination of pentane, previously chlorinated under cooling (at 10 to 30oC). The experiments were carried out with a Co60 radiation source of 330 c at a dosage rate of 8 x 103 to 8 x 104r/hr, in a heated reaction mixture, mixed with a chlorine stream for periods not exceeding 30 hr. It was found that also this type of chlorination and cyclization takes place at a temperature substantially lower than the conventional 500-600oC. According to the experiments, in this case it is advisable to raise the initial temperature of 170oC of the reaction gradually to 220oC with the progress of the reaction, in order to promote the cyclization reaction. It was found, namely, that first the paraffin chain was further chlorinated and later the perchlorinated pentane derivatives cyclize partly to octachloro-cyclopentene, under formation of other chlorinated alkane and alkene derivatives. This reaction mechanism was also supported by thermodynamical calculations. The end product contains three main components; its content of octachloro-cyclopentene ranges between 25 and 35%. The data required for the evaluation of the economy of the method will be available only on the

  11. Investigation of the reaction 35Cl(n,γ)36Cl

    International Nuclear Information System (INIS)

    The γ-radiation following capture of non-polarized thermal neutrons in 35Cl has been investigated. Of the 420 γ-rays ascribed to the 35Cl(n,γ)36Cl reaction, 236 have been placed in a 36Cl decay scheme. The branching ratios and the excitation energies (with 0.04-0.9 KeV errors) of 72 bound states have been determined. Spin assignments and spin restrictions or confirmations have been made for a total of 20 levels. The multipole mixing ratios for some primary γ-ray transitions have been determined. There exists a significant correlation between (d,p) stripping strengths and (n,γ) reduced primary transition probabilities for transitions to lsub(n)(d,p) = 0 levels

  12. Evidence for rapid inter- and intramolecular chlorine transfer reactions of histamine and carnosine chloramines: implications for the prevention of hypochlorous-acid-mediated damage.

    Science.gov (United States)

    Pattison, David I; Davies, Michael J

    2006-07-01

    Hypochlorous acid (HOCl) is a powerful oxidant generated from H(2)O(2) and Cl(-) by the heme enzyme myeloperoxidase, which is released from activated leukocytes. HOCl possesses potent antibacterial properties, but excessive production can lead to host tissue damage that is implicated in a wide range of human diseases (e.g., atherosclerosis). Histamine and carnosine have been proposed as protective agents against such damage. However, as recent studies have shown that histidine-containing compounds readily form imidazole chloramines that can rapidly chlorinate other targets, it was hypothesized that similar reactions may occur with histamine and carnosine, leading to propagation, rather than prevention, of HOCl-mediated damage. In this study, the reactions of HOCl with histamine, histidine, carnosine, and other compounds containing imidazole and free amine sites were examined. In all cases, rapid formation (k, 1.6 x 10(5) M(-)(1) s(-)(1)) of imidazole chloramines was observed, followed by chlorine transfer to yield more stable, primary chloramines (R-NHCl). The rates of most of these secondary reactions are dependent upon substrate concentrations, consistent with intermolecular mechanisms (k, 10(3)-10(4) M(-)(1) s(-)(1)). However, for carnosine, the imidazole chloramine transfer rates are independent of the concentration, indicative of intramolecular processes (k, 0.6 s(-)(1)). High-performance liquid chromatography studies show that in all cases the resultant R-NHCl species can slowly chlorinate N-alpha-acetyl-Tyr. Thus, the current data indicate that the chloramines formed on the imidazole and free amine groups of these compounds can oxidize other target molecules but with limited efficiency, suggesting that histamine and particularly carnosine may be able to limit HOCl-mediated oxidation in vivo. PMID:16800640

  13. Study for Nuclear Structures of 22-35Na Isotopes via Measurements of Reaction Cross Sections

    Science.gov (United States)

    Suzuki, Shinji

    2014-09-01

    T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn., Kochi Univ. of Tech.) Reaction cross sections (σR) for 22-35Na isotopes have been measured at around 240 MeV/nucleon. The σR for 22-35Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. These enhancement can be mainly ascribed to the nuclear deformation. We will discuss the nuclear structure (neutron skin, nuclear shell structure) for neutron-excess Na isotopes. T. Ohtsubo, M. Nagashima, T. Ogura, Y. Shimbara (Grad. Sch. of Sc., Niigata Univ.), M.Takechi, H. Geissel, M. Winkler (GSI), D. Nishimura, T. Sumikama (Dept. of Phys., Tokyo Univ. of Sc.), M. Fukuda, M. Mihara, H. Uenishi (Dept. of Phys., Osaka Univ.), T. Kuboki, T. Suzuki, T. Yamaguchi, H. Furuki, C. S. Lee, K. Sato (Dept. of Phys., Saitama Univ.), A. Ozawa, H. Ohnishi, T. Moriguchi, S. Fukuda, Y. Ishibashi, D. Nagae, R. Nishikiori, T. Niwa (Inst. of Phys., Univ. of Tsukuba), N. Aoi (RCNP), Rui-Jiu Chen, N. Inabe, D. Kameda, T. Kubo, M. Lantz, T. Ohnishi, K. Okumura, H. Sakurai, H. Suzuki, H. Takeda, S. Takeuchi, K. Tanaka, Y. Yanagisawa (RIKEN), De-Qing Fang, Yu-Gang Ma (SINAP), T. Izumikawa (RI Ctr., Niigata Univ.), and S. Momota (Fac. of Engn

  14. 甘油氯化制备二氯丙醇反应的工艺研究%Study on Preparation of Dichloroproanol Reaction with Chlorinated Glycerol

    Institute of Scientific and Technical Information of China (English)

    徐宝刚; 唐国斌; 李丽君

    2013-01-01

      在自制反应装置中,以己二酸为催化剂,考察了各种因素对甘油氯化制备二氯丙醇反应的影响。实验结果表明,甘油氯化的较优条件是:催化剂己二酸用量为甘油质量的6%~7%,反应温度110~120益,带水剂甲苯,二氯丙醇的收率达到90%。催化剂己二酸重复使用5次活性不下降。%In our self-made reactor, the influence of various factors to prepare reaction of glycerol chloride system is inspected. The experimental result shows the optimum conditions of chlorination of glycerol as follows: the catalyst dosage of glycerol adipate meets the quality of 6%~7%, reaction temperature meets 110~120℃, the water-entrainer toluene, two chlorine propanol yield reached 90%. The catalyst can be reused 5 times without activity of adipic acid decreased.

  15. Transformation pathways and acute toxicity variation of 4-hydroxyl benzophenone in chlorination disinfection process.

    Science.gov (United States)

    Liu, Wei; Wei, Dongbin; Liu, Qi; Du, Yuguo

    2016-07-01

    Benzophenones compounds (BPs) are widely used as UV filters, and have been frequently found in multiple environmental matrices. The residual of BPs in water would cause potential threats on ecological safety and human health. Chlorination disinfection is necessary in water treatment process, in which many chemicals remained in water would react with disinfectant chlorine and form toxic by-products. By using ultra performance liquid phase chromatography quadrupole time of flight mass spectrometer (UPLC-QTOF-MS), nuclear magnetic resonance (NMR), the transformation of 4-hydroxyl benezophenone (4HB) with free available chlorine (FAC) was characterized. Eight major products were detected and seven of them were identified. Transformation pathways of 4HB under acid, neutral, and alkaline conditions were proposed respectively. The transformation mechanisms involved electrophilic chlorine substitution of 4HB, Baeyer-Villiger oxidation of ketones, hydrolysis of esters and oxidative breakage of benzene ring. The orthogonal experiments of pH and dosages of disinfectant chlorine were conducted. The results suggested that pH conditions determined the occurrence of reaction types, and the dosages of disinfectant chlorine affected the extent of reactions. Photobacterium assay demonstrated that acute toxicity had significant increase after chlorination disinfection of 4HB. It was proved that 3,5-dichloro-4HB, one of the major transformation products, was responsible for the increasing acute toxicity after chlorination. It is notable that, 4HB at low level in real ambient water matrices could be transformed during simulated chlorination disinfection practice. Especially, two major products 3-chloro-4HB and 3,5-dichloro-4HB were detected out, implying the potential ecological risk after chlorination disinfection of 4HB.

  16. Transformation pathways and acute toxicity variation of 4-hydroxyl benzophenone in chlorination disinfection process.

    Science.gov (United States)

    Liu, Wei; Wei, Dongbin; Liu, Qi; Du, Yuguo

    2016-07-01

    Benzophenones compounds (BPs) are widely used as UV filters, and have been frequently found in multiple environmental matrices. The residual of BPs in water would cause potential threats on ecological safety and human health. Chlorination disinfection is necessary in water treatment process, in which many chemicals remained in water would react with disinfectant chlorine and form toxic by-products. By using ultra performance liquid phase chromatography quadrupole time of flight mass spectrometer (UPLC-QTOF-MS), nuclear magnetic resonance (NMR), the transformation of 4-hydroxyl benezophenone (4HB) with free available chlorine (FAC) was characterized. Eight major products were detected and seven of them were identified. Transformation pathways of 4HB under acid, neutral, and alkaline conditions were proposed respectively. The transformation mechanisms involved electrophilic chlorine substitution of 4HB, Baeyer-Villiger oxidation of ketones, hydrolysis of esters and oxidative breakage of benzene ring. The orthogonal experiments of pH and dosages of disinfectant chlorine were conducted. The results suggested that pH conditions determined the occurrence of reaction types, and the dosages of disinfectant chlorine affected the extent of reactions. Photobacterium assay demonstrated that acute toxicity had significant increase after chlorination disinfection of 4HB. It was proved that 3,5-dichloro-4HB, one of the major transformation products, was responsible for the increasing acute toxicity after chlorination. It is notable that, 4HB at low level in real ambient water matrices could be transformed during simulated chlorination disinfection practice. Especially, two major products 3-chloro-4HB and 3,5-dichloro-4HB were detected out, implying the potential ecological risk after chlorination disinfection of 4HB. PMID:27085063

  17. Synthesis and chlorination of manganese-columbine by means of a solid-gas reaction. Determination of crystalline structures

    International Nuclear Information System (INIS)

    Full text. The synthesis of mangano-columbite was carried out as follows: Mixing of N B 203 and Mn Cl 2 with an 10% weight excess of the latter in order to compensate for losses due to volatilization; grinding of the mixture in an agate mortar with agate handle in order to achieve close contact between the two solids; calcination of the sample in a quartz crucible at temperatures between 610 and 620 C (fusion temperature for Mn Cl2) in N2 current for six hours. After this time, temperature was increased at a eat of 50 C/h until reaching 800 C. This temperature was maintained for two hours in order to eliminate Mn Cl2 excess; cooling of the obtained product in N2 current. XRD analysis showed that the obtained products is a mangano-columbite. The mineral in natural state presents and orthorhombic structure. The structure of the synthesized product, though corresponding to mangano-columbite according to DRX, should be confirmed by means of an additional technique such as EXAFS. Th mangano-columbite obtained was subsequently chlorinated at 900 deg C for two hours to obtain conversions close to 50%, at 101 kPa, with a chlorine molar fraction of 1 and a flow of 50 cm3/min. By XRD it can be observed that the chlorination residue presents unreacted mangano-columbite and niobium oxide in an unknown phase, whose crystalline structure is currently under study. Measurements to be performed by means Synchrotron Radiation (EXAFS and XANES) might help elucidate this new structure. (author)

  18. Chlorine and antibiotic-resistant bacilli isolated from an effluent treatment plant - doi: 10.4025/actascitechnol.v35i1.12951

    Directory of Open Access Journals (Sweden)

    Suzana Cláudia Silveira Martins

    2013-01-01

    Full Text Available Resistance to different concentrations of chlorine and the susceptibility to antibiotics by bacteria isolated from the final effluent of the Pici Campus wastewater treatment plant of the Federal University of Ceará (UFC is evaluated. Twelve strains, morphologically and biochemically identified as belonging to the genus Bacillus, were selected. The strains were submitted to sodium hypochlorite at different contact times and tested against the antibiotics amoxicillin, erythromycin, chloramphenicol, tetracycline, and vancomycin. All strains were resistant to concentration 0.1 ppm chlorine up to 30 minutes, but bacteria resistant to concentrations up to 5,000 ppm for 10 minutes were detected. Bacterial growth was impaired in 10,000 ppm concentration. The strains presented three antibiotic resistance profiles, 50% were sensitive to all antibiotics, 25% were resistant to one antibiotic and 25% were resistant to two antibiotics.  

  19. Transformation reactions and recycling of carotenoids and chlorins in the Peru upwelling region (15°S, 75°W)

    Science.gov (United States)

    Repeta, Daniel J.; Gagosian, Robert B.

    1984-06-01

    Total chlorins and carotenoids were measured in suspended paniculate matter, sediment trap, and zooplankton fecal pellet samples collected in the Peru upwelling region. Individual carotenoids were analyzed by high pressure liquid chromatography and mass spectrometry. Fucoxanthin, diadinoxanthin, diatoxanthin, carotene, and peridinin constitute > 95% of the total carotenoid pigments in suspended paniculate matter samples. However, sediment trap and zooplankton fecal pellet samples contained significant amounts of the carotenoid transformation products fucoxanthinol, fucoxanthin 5'-dehydrate, fucoxanthinol 5'-dehydrate, peridininol and peridininol 5'-dehydrate. These samples were further characterized by high values of the ratio fucoxanthinol/total fucopigments ( f/F t) and low values of the ratio total carotenoids /total chlorins. Three reactions are proposed to account for the formation of observed products: heterotrophic ester hydrolysis, chemically mediated epoxide rearrangement, and microbially mediated dehydration. The distribution of specific transformation products within the samples suggests that heterotrophic ester hydrolysis is a general transformation pathway operative in the water column on a wide suite of organic esters. Epoxide rearrangement and dehydration appear to occur over a longer time scale and are more typical of sedimentary environments.

  20. An elementary reaction kinetic model of the gas-phase formation of polychlorinated dibenzofurans from chlorinated phenols

    Energy Technology Data Exchange (ETDEWEB)

    Dellinger, B.; Khachatryan, L. [Louisiana State Univ., Baton Rouge, LA (United States); Asatryan, R. [State Medical Univ., Yerevan (Armenia)

    2004-09-15

    Combustion and thermal processes are generally recognized as the major source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F or simply ''dioxins'') in the environment. A previously developed, simple mechanism of gas-phase formation of PCDD from chlorinated phenols suggested that the gas-phase formation pathway was too slow to account for concentrations of PCDD observed in full-scale combustors. As a result, most research on formation of PCDD/F in combustion sources focused on surface-mediated formation. In this manuscript, we report the development of a modified model for the purely gas-phase formation of polychlorinated dibenzofurans (PCDFs) that is based on the experimentally observed formation of PCDF from the oxidation of 2,4,6-trichlorophenol (TCP) in the presence of hexane.

  1. Experimental Study of Closed System in the Chlorine Dioxide-Iodide-Sulfuric Acid Reaction by UV-Vis Spectrophotometric Method

    OpenAIRE

    Na Li; Laishun Shi; Xiaomei Wang; Fang Guo; Chunying Yan

    2011-01-01

    The mole ratio r(r = [I−]0/[ClO2]0) has great influence on ClO2-I−-H2SO4 closed reaction system. By changing the initiate concentration of potassium iodide, the curve of absorbance along with the reaction time was obtained at 350 nm and 297 nm for triiodide ion, and 460 nm for iodine. The changing point of the absorbance curve's shape locates at r = 6.00. For the reaction of ClO2-I− in the absence of H2SO4, the curve of absorbance along with the reaction time can be obtained at 350 nm for tri...

  2. Kinetic study of neodymium oxide chlorination with gaseous chlorine

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, Marta V., E-mail: marta.bosco@cab.cnea.gov.ar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Fouga, Gaston G. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Complejo Tecnologico Pilcaniyeu, Comision Nacional de Energia Atomica, Avenida Bustillo 9500, CP 8400 San Carlos de Bariloche (Argentina); Bohe, Ana E. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Complejo Tecnologico Pilcaniyeu, Comision Nacional de Energia Atomica, Avenida Bustillo 9500, CP 8400 San Carlos de Bariloche (Argentina); Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, CP 8400 San Carlos de Bariloche (Argentina)

    2012-07-20

    Highlights: Black-Right-Pointing-Pointer We analyze the kinetics of the neodymium oxide chlorination reactions. Black-Right-Pointing-Pointer For temperatures below 425 Degree-Sign C the system is under chemical control. Black-Right-Pointing-Pointer The formation of oxychloride progresses through a nucleation and growth mechanism. Black-Right-Pointing-Pointer A reaction order of 0.40 with respect to chlorine partial pressure was determined. Black-Right-Pointing-Pointer An activation energy of 161 {+-} 4 kJ mol{sup -1} was determined. - Abstract: The kinetics of the chlorination of neodymium oxide has been investigated by thermogravimetry between 312 Degree-Sign C and 475 Degree-Sign C, and for partial pressures of chlorine ranging from 10 kPa to 50 kPa. The starting temperature for the reaction of neodymium oxide with chlorine was determined to be about 250 Degree-Sign C, leading to neodymium oxychloride as product. The results showed that, for temperatures below 425 Degree-Sign C, the system is under chemical control and the formation of the oxychloride progresses through a nucleation and growth mechanism. The influence of chlorine mass transport through the bulk gas phase and through the boundary layer on the overall reaction rate was analyzed. In the absence of these two mass-transfer steps, a reaction order of 0.39 with respect to chlorine partial pressure, and an activation energy of 161 {+-} 4 kJ mol{sup -1} were determined. A complete rate equation has been successfully developed.

  3. 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.

  4. Method of obtaining sulphur-labelled compounds by reaction of ''hot'' sulphur-35 atoms with cyclic hydrocarbons

    International Nuclear Information System (INIS)

    The authors discuss methods of obtaining sulphur-labelled compounds, such as aliphatic and cyclic mercaptans and sulphides, by direct synthesis employing recoil atoms from the reaction Cl35 (n, p) S35. Hot S35 atoms were obtained in the middle of the target substance by exposing mixtures of C Cl4 and a cyclic hydrocarbon (cyclopentane, cyelohexane) to neutrons in a reactor. A method is given for irradiating the mixtures and then separating the various sulphur-bearing compounds by specific chemical methods, rectification, and paper and gas-liquid chromatography. The purpose of the exchange is clarified. The relation of the yield of the separated sulphur-labelled products to the composition of the mixture and type of exposure was investigated, and an active-sulphur balance settled. New types of atomic sulphur reactions were established: the CH2-group is replaced and implanted on the C-C link. The cyclic molecule is destroyed in the interaction with the hot sulphur atoms. Hot sulphur atoms can initiate the formation of polymers containing sulphur. The yields of these reactions were established. Up to 98% of the active sulphur is linked in the form of organic sulphur compounds. It was shown that sulphur-labelled thiophene, tetrahydrothiopyrane, cyclopentyl-mercaptan, cyclohexylmercaptan, ethyl-propyl-butyl-mercaptans, dicyclopentyl-sulphide, polymeric mercaptans and sulphides could be synthesized by heat. I t is possible to regulate within broad limits the yield of various labelled compounds by changing the decelerating properties of the medium. (author)

  5. A Novel Approach to Prepare Well-Defined Silica-Supported Polyoxometalate Species by Reaction with a Chlorinated Support

    Directory of Open Access Journals (Sweden)

    Eva Grinenval

    2013-01-01

    Full Text Available Polyoxometalates were grafted covalently on SBA-15 by a two-step procedure. The dehydroxylated mesoporous silica was first modified by reaction with methyltrichlorosilane in presence of triethylamine. The resulting solid was fully characterized and contained a mixture of mono- and digrafted species . These surface Si–Cl bonds can react with lacunary polyoxometalates as in solution, yielding to a ≡Si–O–POM linkage. However, solid state MAS NMR shows that only the digrafted species react with the polyoxometalate. This new grafting method opens the way to the synthesis of a new class of catalysts which could operate in solution without leaching.

  6. Reply to Two Comments on "Dark matter searches going bananas the contribution of Potassium (and Chlorine) to the 3.5 keV line"

    CERN Document Server

    Jeltema, Tesla

    2014-01-01

    We respond to two comments on our recent paper, Jeltema & Profumo (2014). The first comment by Boyarsky et al. confirms the absence of a line from M31 in the 3-4 keV energy range, but criticizes the energy range for spectral fitting on the basis that (i) the background model adopted between 3-4 keV is invalid outside that range and that (ii) extending the energy range multiple features appear, including a 3.5 keV line. Point (i) is manifestly irrelevant (the 3-4 keV background model was not meant to extend outside that range), while closer inspection of point (ii) shows that the detected features are inconsistent and likely unphysical. We demonstrate that the existence of an excess near 3.5 keV in the M31 data requires fitting a broad enough energy range such that the background modeling near 3.5 keV is poor to a level that multiple spurious residual features become significant. Bulbul et al. criticize our use of WebGuide instead of the full AtomDB package. While a technically correct remark, this is only...

  7. Theoretical studies on proton transfer reaction of 3(5)-substituted pyrazoles

    Indian Academy of Sciences (India)

    Alireza Najafi Chermahini; Abbas Teimouri

    2014-01-01

    The inter and intra molecular proton transfer reactions of a series of pyrazole derivatives have been studied by using density functional theory (DFT) andMP2 methods implementing 6-311++G(d,p) atomic basis set. The substituents have been selected to cover a wide range of electronic effects. Proton transfer process was studied for mechanisms including single proton transfer, double proton transfer and proton transfer assisted by a water or ammonia molecule. The results showed single proton transfer reactions for interconversion pyrazole derivatives need highest activation energies in the range of 45.7−51.59 and 49.4−53.96 kcal/mol at B3LYP and MP2 levels, respectively. It was found that for the 3-substituted pyrazoles, electron withdrawing groups form stronger dimers but in the 5-substituted tautomers electron donating groups form stronger hydrogen bond. The double proton transfer reactions between dimers were studied and transition states calculated. The ranges of activation energies were found to be 17.51−19.36 and 17.02−17.80 kcal/mol for the C → E and D → D reactions respectively. In addition, the activation energies for the proton transfer reaction assisted by water or ammonia molecules were found to be in the range of 26.62−31.78 and 17.25−22.46 kcal/mol, respectively, calculated at MP2/6-311++G(d,p) level of theory.

  8. High-flux white neutron source based on p(35)-Be reactions for activation experiments at NPI

    International Nuclear Information System (INIS)

    The concept of International Fusion Material Irradiation Facility (IFMIF) is based on the d(40)-Li neutron source reaction which produces the white neutron spectrum with mean energy of 14 MeV, energy range with high intensity of neutron beam up to 35 MeV, and weak tail up to 55 MeV. At the Nuclear Physics Institute of the ASCR in Rez near Prague, the source reaction of p+Be was investigated for proton energy of 35 MeV and beam current intensity of 9.2μA. The produced white spectrum with neutron flux up to 1011 cm−2 s−1 was determined by the dosimetry foils activation technique at two sample-to-target distances and validated against the Monte Carlo predictions. The neutron field of these high-flux p(35)-Be white neutron source represents the useful tool for experimental simulation of the spectrum of the IFMIF facility, validating the activation cross-section data in the energy range relevant to the IFMIF, studying the radiation hardness of electronics against the high-energy neutron fields, and various activation experiments. - Highlights: • Development of accelerator-driven neutron sources. • Fast neutron spectrometry. • Multi-foil activation technique. • Nuclear data measurement and validation in the energy range of IFMIF

  9. Consequence analysis of IWTS metal water reactions (Fauske and Associates report 99-35)

    Energy Technology Data Exchange (ETDEWEB)

    DUNCAN, D.R.

    1999-07-28

    The report describes the consequences of postulated thermally unstable conditions in the IWTS knock out pot. The consequence analysis shows that both the knock out pot and particulate bed will stay intact, and that releases will be minor. Reaction rate limitations prevent knock out pot pressure and/or temperature from even approaching values that would threaten structural integrity. Source term calculations based on a particle bed with a homogeneous mixture of metal and oxide particles yield a release above the K Basin pool of about 12 grams.

  10. Dynamical approach to spectator fragmentation in Au+Au reactions at 35 MeV/A

    CERN Document Server

    Vermani, Yogesh K

    2010-01-01

    The characteristics of fragment emission in peripheral $^{197}$Au+$^{197}$Au collisions 35 MeV/A are studied using the two clusterization approaches within framework of \\emph{quantum molecular dynamics} model. Our model calculations using \\emph{minimum spanning tree} (MST) algorithm and advanced clusterization method namely \\emph{simulated annealing clusterization algorithm} (SACA) showed that fragment structure can be realized at an earlier time when spectators contribute significantly toward the fragment production even at such a low incident energy. Comparison of model predictions with experimental data reveals that SACA method can nicely reproduce the fragment charge yields and mean charge of the heaviest fragment. This reflects suitability of SACA method over conventional clusterization techniques to investigate spectator matter fragmentation in low energy domain.

  11. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    International Nuclear Information System (INIS)

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m3 d−1 design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L−1; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L−1), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L−1) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions

  12. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Larry B. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); Hladik, Michelle L. [U.S. Geological Survey, 6000 J Street Placer Hall, Sacramento, CA 95819 (United States); Vajda, Alan M. [University of Colorado, Department of Integrative Biology, CB 171, Denver, CO 80217 (United States); Fitzgerald, Kevin C. [U.S. Geological Survey, 3215 Marine St., Boulder, CO 80303 (United States); AECOM, 500 West Jefferson St., Ste. 1600, Louisville, KY 40202 (United States); Douville, Chris [City of Boulder, 4049 75th Street, Boulder, CO 80301 (United States)

    2015-10-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m{sup 3} d{sup −1} design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration = 2.7 μg L{sup −1}; n = 5) and 10 HDBPs (mean total concentration = 4.5 μg L{sup −1}), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration = 1.4 μg L{sup −1}) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had

  13. Transformation of iopamidol during chlorination.

    Science.gov (United States)

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

    2014-11-01

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

  14. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection.

    Science.gov (United States)

    Barber, Larry B; Hladik, Michelle L; Vajda, Alan M; Fitzgerald, Kevin C; Douville, Chris

    2015-10-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m(3) d(-1) design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration=2.7 μg L(-1); n=5) and 10 HDBPs (mean total concentration=4.5 μg L(-1)), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration=1.4 μg L(-1)) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions of

  15. Impact of wastewater infrastructure upgrades on the urban water cycle: Reduction in halogenated reaction byproducts following conversion from chlorine gas to ultraviolet light disinfection.

    Science.gov (United States)

    Barber, Larry B; Hladik, Michelle L; Vajda, Alan M; Fitzgerald, Kevin C; Douville, Chris

    2015-10-01

    The municipal wastewater treatment facility (WWTF) infrastructure of the United States is being upgraded to expand capacity and improve treatment, which provides opportunities to assess the impact of full-scale operational changes on water quality. Many WWTFs disinfect their effluent prior to discharge using chlorine gas, which reacts with natural and synthetic organic matter to form halogenated disinfection byproducts (HDBPs). Because HDBPs are ubiquitous in chlorine-disinfected drinking water and have adverse human health implications, their concentrations are regulated in potable water supplies. Less is known about the formation and occurrence of HDBPs in disinfected WWTF effluents that are discharged to surface waters and become part of the de facto wastewater reuse cycle. This study investigated HDBPs in the urban water cycle from the stream source of the chlorinated municipal tap water that comprises the WWTF inflow, to the final WWTF effluent disinfection process before discharge back to the stream. The impact of conversion from chlorine-gas to low-pressure ultraviolet light (UV) disinfection at a full-scale (68,000 m(3) d(-1) design flow) WWTF on HDBP concentrations in the final effluent was assessed, as was transport and attenuation in the receiving stream. Nutrients and trace elements (boron, copper, and uranium) were used to characterize the different urban source waters, and indicated that the pre-upgrade and post-upgrade water chemistry was similar and insensitive to the disinfection process. Chlorinated tap water during the pre-upgrade and post-upgrade samplings contained 11 (mean total concentration=2.7 μg L(-1); n=5) and 10 HDBPs (mean total concentration=4.5 μg L(-1)), respectively. Under chlorine-gas disinfection conditions 13 HDBPs (mean total concentration=1.4 μg L(-1)) were detected in the WWTF effluent, whereas under UV disinfection conditions, only one HDBP was detected. The chlorinated WWTF effluent had greater relative proportions of

  16. 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.

  17. Detection of nonauthorized genetically modified organisms using differential quantitative polymerase chain reaction: application to 35S in maize.

    Science.gov (United States)

    Cankar, Katarina; Chauvensy-Ancel, Valérie; Fortabat, Marie-Noelle; Gruden, Kristina; Kobilinsky, André; Zel, Jana; Bertheau, Yves

    2008-05-15

    Detection of nonauthorized genetically modified organisms (GMOs) has always presented an analytical challenge because the complete sequence data needed to detect them are generally unavailable although sequence similarity to known GMOs can be expected. A new approach, differential quantitative polymerase chain reaction (PCR), for detection of nonauthorized GMOs is presented here. This method is based on the presence of several common elements (e.g., promoter, genes of interest) in different GMOs. A statistical model was developed to study the difference between the number of molecules of such a common sequence and the number of molecules identifying the approved GMO (as determined by border-fragment-based PCR) and the donor organism of the common sequence. When this difference differs statistically from zero, the presence of a nonauthorized GMO can be inferred. The interest and scope of such an approach were tested on a case study of different proportions of genetically modified maize events, with the P35S promoter as the Cauliflower Mosaic Virus common sequence. The presence of a nonauthorized GMO was successfully detected in the mixtures analyzed and in the presence of (donor organism of P35S promoter). This method could be easily transposed to other common GMO sequences and other species and is applicable to other detection areas such as microbiology.

  18. A convenient route to symmetrically and unsymmetrically substituted 3,5-diaryl-2,4,6-trimethylpyridines via Suzuki–Miyaura cross-coupling reaction

    Science.gov (United States)

    Szawkało, Joanna; Czarnocki, Zbigniew

    2016-01-01

    Summary A series of differently substituted 3,5-diaryl-2,4,6-trimethylpyridines were prepared and characterized using the Suzuki–Miyaura coupling reaction with accordingly selected bromo-derivatives and arylboronic acids. The reaction conditions were carefully optimized allowing high yield of isolated products and also the construction of unsymmetrically substituted diarylpyridines, difficult to access by other methods. PMID:27340474

  19. Experimental investigation of the 19F( n, α)16N reaction excitation function in the neutron energy range of 4 to 7.35 MeV

    Science.gov (United States)

    Bondarenko, I. P.; Khryachkov, V. A.; Ivanova, T. A.; Kuz'minov, B. D.; Semenova, N. N.; Sergachev, A. I.

    2013-07-01

    The interaction of neutrons with light nuclei study is of interest for understanding nuclear-reaction mechanisms. Fluorine nuclei are worth particular attention because they are abundant in the core of the promising molten-salt reactors and can noticeably affect the chain reaction kinetics. In this work we have experimentally investigated the 19F( n, α)16N reaction cross-section at neutron energies ranging from 4 to 7.35 MeV.

  20. 钌镧氧化物涂层析氯反应动力学比较研究%Comparative Study on Kinetics of Chlorine Evolution Reaction for Ru-La-O Oxide Coatings

    Institute of Scientific and Technical Information of China (English)

    龙萍; 许立坤; 崔秀芳; 金国

    2015-01-01

    通过热分解法制备了Ti/RuO2和Ti/Ru-La-O氧化物涂层,利用微分电容和极化曲线等实验方法对涂层Clˉ特性吸附、La对RuO2涂层析氯反应过程的影响及反应机理进行了研究.结果表明,在NaCl溶液中,涂层表面存在Clˉ的特性吸附,这种特性吸附对析氯反应的动力学产生了影响,导致Tafel斜率上升,反应级数下降,加入La使氧化钌涂层的过电位下降,交换电流密度增大,有利于析氯反应的进行.本文对涂层存在的两种可能反应机理进行了比较分析,认为在中性NaCl溶液中析氯反应是由2≡S·OCl*(rds→)≡S·O +Cl2过程控制的.%The Ti/RuO2 and Ti/Ru-La-O oxide coatings were prepared by thermal decomposition of the metal chlorides in the precursor solution. The specific adsorption of Clˉ on coatings, the effect of La on the chlorine evo-lution reactions (ClER) and the kinetic mechanism were investigated by using differential capacity (DC) and po-larization curves (PC). Results show that the coating surface exhibits significantly specific adsorption of Clˉ in NaCl neutral solution, which has an influence on the kinetics of the chlorine evolution process, resulting in an in-crease of the Tafel slope and a decrease of the reaction order. The addition of lanthanum reduces the overpotential of Ti/RuO2 coating and enhances the exchange current density, which improves the chlorine evolution reaction of the coatings. Both kinetic mechanisms of recombination and electrochemical desorption of adsorbed intermediate species for the coatings are comparatively studied. It is confirmed that the Chlorine evolution reaction on Ru-La-O oxide coatings in NaCl neutral solution is controlled by the process of 2≡ S· OCl* (rds→)≡ S·O +Cl2.

  1. [Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

    Science.gov (United States)

    Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

    2010-01-01

    In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

  2. Surto de reações hemolíticas associado a residuais de cloro e cloraminas na água de hemodiálise Outbreak of hemolytic reactions associated with chlorine and chloramine residuals in hemodialysis water

    Directory of Open Access Journals (Sweden)

    Rachel VV Calderaro

    2001-10-01

    Full Text Available OBJETIVO: Relatar o processo de investigação da contaminação da água e a conseqüente avaliação do surto ocorrido no serviço de hemodiálise. MÉTODOS: Em setembro de 2000, 16 pacientes sob terapia de hemodiálise de um hospital em Minas Gerais apresentaram reações hemolíticas compatíveis a sintomas de intoxicação por cloro e cloramina em água. Foi feita a medição das concentrações de cloro e cloramina em amostras coletadas em diversos pontos do sistema de tratamento e distribuição de água do serviço inspecionado. A identificação dos casos ocorridos durante o período de estudo foi feita pela revisão das anotações de prontuários dos pacientes. Foi feita a revisão dos procedimentos da equipe técnica, médica e de enfermagem por meio de entrevistas. RESULTADOS: A taxa de sintomas foi significativamente alta (pOBJECTIVE: To investigate the process of water contamination and to assess the subsequent outbreak in the hemodialysis center. METHODS: In September 2000, sixteen patients undergoing chronic hemodialysis at a dialysis center in Minas Gerais, Brazil, experienced hemolytic reactions compatible with toxic symptoms due to chlorine and chloramine water contamination. Chlorine and chloramine concentrations in samples obtained from various sites of the dialysis center's water treatment and distribution system were measured. Case-patients were identified by reviewing medical records and nursing notes for all dialysis sessions carried out during the study period. Interviews with technicians, nursing and medical staff members were conducted. RESULTS: Reaction rate was significantly higher (p£0.5 mg/L for chlorine and £ 0.1 mg/L for chloramine. Individuals exposed to high chlorine and chloramine concentrations presented a relative risk of 2.58 (1.0-6.28 of having hemolytic reactions. CONCLUSION: There is a need to observe surveillance procedures to secure that the maximum allowable concentrations of regulated substances

  3. Electromigration-induced cracks in Cu/Sn3.5Ag/Cu solder reaction couple at room temperature

    Institute of Scientific and Technical Information of China (English)

    He Hongwen; Xu Guangchen; Guo Fu

    2009-01-01

    Electromigration (EM) behavior of Cu/Sn3.5Ag/Cu solder reaction couple was investigated with a high current density of 5× 103 A/cm2 at room temperature. One dimensional structure, copper wire/solder ball/copper wire SRC was designed and fabricated to dissipate the Joule heating induced by the current flow. In addition, thermomigration effect was excluded due to the symmetrical structure of the SRC. The experimental results in-dicated that micro-cracks initially appeared near the cathode interface between solder matrix and copper substrate after 474 h current stressing. With current stressing time increased, the cracks propagated and extended along the cathode interface. It should be noted that the continuous Cu6Sn5 intcrmetallic compounds (LMCs) layer both at the anode and at the cathode remained their sizes. Interestingly, tiny cracks appeared at the root of some long column-type Cu6Sn5 at the cathode interface due to the thermal stress.

  4. Decay studies of 59Cu* formed in the 35Cl + 24Mg reaction using the dynamical cluster-decay model

    Science.gov (United States)

    Karthikraj, C.; Balasubramaniam, M.

    2013-02-01

    The reformulated dynamical cluster-decay model (DCM) is applied to study the decay of odd-A and non-α structured 59Cu* formed in the 35Cl+24Mg reaction at Elab=275 MeV. Here, the temperature (T)-dependent binding energies due to Krappe are used. The roles of Wigner and pairing energies in the fragmentation potential are explicitly shown in this work. For the temperature T=4.1898 MeV corresponding to Elab=275 MeV, the contribution of pairing vanishes and the resulting structure of the fragmentation potential due to Wigner term is shown. In addition to this, we have studied the role of factor α appearing in the inertia part of the equation of motion dictating the mass-transfer process. It is shown that this factor has significant effect in the structure of preformation probability values and hence in turn we see significant changes in the cross sections. We compare the cross sections of the measured charge distributions of the fission fragments for two limiting values of the parameter α with the experimental data. In order to fit the total cross-section values, a linear relation is obtained between the free parameter of the model ▵R and the factor α appearing in the hydrodynamical mass.

  5. Intermediate-mass fragments from nonbinary processes in the reaction of /sup 14/N on Ag at E/A = 35 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bougault, R.; Horn, D.; Chitwood, C.B.; Fields, D.J.; Gelbke, C.K.; Klesch, D.R.; Lynch, W.G.; Tsang, M.B.; Kwiatkowski, K.

    1987-08-01

    Angular distributions of recoil nuclei were measured in coincidence with low-energy intermediate-mass fragments emitted in /sup 14/N-induced reactions on Ag at E/A = 35 MeV. The measured correlations are inconsistent with a purely binary reaction mechanism. The incomplete linear momentum transfer mechanism alone does not reproduce the data, which show evidence for emission of additional matter to the same side of the beam axis as the intermediate-mass fragment.

  6. Technology assessment: Chlorine chemistry

    International Nuclear Information System (INIS)

    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.)

  7. Chlorine Isotopes: As a Possible Tracer of Fluid/Bio-Activities on Mars and a Progress Report on Chlorine Isotope Analysis by TIMs

    Science.gov (United States)

    Nakamura, N.; Nyquist, L.E.; Reese, Y.; Shih, C-Y.; Numata, M.; Fujitani, T.; Okano, O.

    2009-01-01

    Significantly large mass fractionations between chlorine isotopes (Cl-35, Cl-37) have been reported for terrestrial materials including both geological samples and laboratory materials. Also, the chlorine isotopic composition can be used as a tracer for early solar system processes. Moreover, chlorine is ubiquitous on the Martian surface. Typical chlorine abundances in Gusev soils are approx.0.5 %. The global surface average chlorine abundance also is approx.0.5 %. Striking variations among outcrop rocks at Meridiani were reported with some chlorine abundances as high as approx.2%. Characterizing conditions under which chlorine isotopic fractionation may occur is clearly of interest to planetary science. Thus, we have initiated development of a chlorine isotopic analysis technique using TIMS at NASA-JSC. We present here a progress report on the current status of development at JSC and discuss the possible application of chlorine isotopic analysis to Martian meteorites in a search for fluid- and possibly biological activity on Mars.

  8. Fast Hetero-Diels-Alder Reactions Using 4-Phenyl-1,2,4-Triazoline-3,5-Dione (PTAD) as the Dienophile

    Science.gov (United States)

    Celius, Tevye C.

    2010-01-01

    A hetero-Diels-Alder reaction that proceeds rapidly and only requires a simple filtration to purify the product is presented. The dienophile, 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), is prepared by the heterogeneous oxidation of 4-phenylurazole by the bromenium ion, Br[superscript +], generated in situ by the oxidation of potassium bromide by…

  9. Relation between chlorine with the quality of crude water

    International Nuclear Information System (INIS)

    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)

  10. Reaction and fusion cross sections for the near-symmetric system $^{129}Xe+^{nat}Sn$ from $8$ to $35$ $AMeV$

    CERN Document Server

    Manduci, L; Chbihi, A; Rivet, M F; Bougault, R; Frankland, J D; Borderie, B; Galichet, E; La Commara, M; Neindre, N Le; Lombardo, I; Pârlog, M; Rosato, E; Roy, R; Verde, G; Vient, E

    2016-01-01

    \\item[Background]Heavy-ion reactions from barrier up to Fermi energy. \\item[Purpose]Reaction and fusion cross sections determination. Fusion reactions induced by $^{129}Xe$ projectiles on $^{nat}Sn$ targets for energies ranging from $8$ A.MeV to $35$ A.MeV were measured with the INDRA $4\\pi$-array.\\\\ The evaluation of the fusion/incomplete fusion cross sections for the incident energies from 8 to 35 A.MeV is the main purpose of this paper. \\item[Method] The reaction cross sections are evaluated for each beam energy thanks to INDRA $4\\pi$-array. The events are also sorted in order to focus the study on a selected sample of events, in such a way that the fusion/fusion incomplete cross section is estimated. \\item[Results] The excitation function of reaction and fusion cross sections were measured for the heavy and nearly symmetric system $^{129}Xe + ^{nat}Sn$ from 8 to 35 A.MeV. \\item[Conclusions] The fusion-like cross-sections evaluated show a good agrement with a recent systematics for beam energies greater th...

  11. 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.

  12. Kinetics of the Reaction of 2-Chloro-3,5-dinitrobenzotriflouride with Aniline in Toluene and Methanol-Toluene Mixed Solvents

    Institute of Scientific and Technical Information of China (English)

    Fathalla; Magda F.

    2012-01-01

    Kinetics of the reaction of 2-chloro-3,5-dinitrobenzotriflouride with aniline were studied in toluene, metha- nol-toluene binary solvents, benzene and chloroform. The reaction in toluene exhibits third-order kinetics consistent with aggregates of aniline. Thermodynamic parameters AH#, AS# and AG# are calculated and discussed for the reaction of 2-chloro-3,5-dinitrobenzotriflouride with aniline in methanol-toluene. Molecular complexes between aniline and the substrate are rejected spectrophotometricaly. The mechanism is studied and compared with the reac- tion in presence of pyridine. It shows an amine dependence and formation of homo and/or hetero mixed aggregates between aniline and pyridine i.e. dimer mechanism.

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

    Science.gov (United States)

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

    2013-11-15

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

  14. Effects of the temperature and the irradiation on the behaviour of chlorine 37 in nuclear graphite: consequences on the mobility of chlorine 36 in irradiated graphites

    International Nuclear Information System (INIS)

    This thesis deals with the studies of the management of irradiated graphite wastes issued from the dismantling of the UNGG French reactors. This work focuses on the behavior of 36Cl. This radionuclide is mainly issued through the neutron activation of 35Cl by the reaction 35Cl(n, γ)36Cl, pristine chlorine being an impurity of nuclear graphite, present at the level of some at.ppm. 36Cl is a long lived radionuclide (about 300,000 years) and is highly soluble in water and mobile in concrete and clay. The solubilization of 36Cl is controlled by the water accessibility into irradiated graphite pores as well as by factors related to 36Cl itself such as its chemical speciation and its location within the irradiated graphite. Both speciation and chlorine location should strongly influence its behaviour and need to be taken into account for the choice of liable management options. However, data on radioactive chlorine features are difficult to assess in irradiated graphite and are mainly related to detection sensitivity problems. In this context, we simulated and evaluated the impact of the temperature, the irradiation and the radiolytic oxidation on the chlorine 36 behaviour. In order to simulate the presence of 36Cl, we implanted 37Cl into virgin nuclear graphite. Ion implantation has been widely used to study the lattice location, the diffusion and the release of fission and activation products in nuclear materials. Our results on the comparative effects of the temperature and the irradiation show that chlorine occurs in irradiated graphite on temperature and electronic and nuclear irradiation improve this effect. (author)

  15. Mechanisms of inactivation of poliovirus by chlorine dioxide and iodine.

    OpenAIRE

    Alvarez, M E; O'Brien, R T

    1982-01-01

    Chlorine dioxide and iodine inactivated poliovirus more efficiently at pH 10.0 than at pH 6.0. Sedimentation analyses of viruses inactivated by chlorine dioxide and iodine at pH 10.9 showed that viral RNA separated from the capsids, resulting in the conversion of virions from 156S structures to 80S particles. The RNAs release from both chlorine dioxide- and iodine-inactivated viruses cosedimented with intact 35S viral RNA. Both chlorine dioxide and iodine reacted with the capsid proteins of p...

  16. 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.

  17. Enhanced Elemental Mercury Removal from Coal-fired Flue Gas by Sulfur-chlorine Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shih-Ger; Yan, Nai-Qiang; Qu, Zan; Chi, Yao; Qiao, Shao-Hua; Dod, Ray; Chang, Shih-Ger; Miller, Charles

    2008-07-02

    Oxidation of Hg0 with any oxidant or converting it to a particle-bound form can facilitate its removal. Two sulfur-chlorine compounds, sulfur dichloride (SCl2) and sulfur monochloride (S2Cl2), were investigated as oxidants for Hg0 by gas phase reaction and by surface-involved reactions in the presence of flyash or activated carbon. The gas phase reaction rate constants between Hg0 and the sulfur/chlorine compounds were determined, and the effects of temperature and the main components in flue gases were studied. The gas phase reaction between Hg0 and SCl2 is shown to be more rapid than the gas phase reaction with chlorine, and the second order rate constant was 9.1(+-0.5) x 10-18 mL-molecules-1cdots-1 at 373oK. Nitric oxide (NO) inhibited the gas phase reaction of Hg0 with sulfur-chlorine compounds. The presence of flyash or powdered activated carbon in flue gas can substantially accelerate the reaction. The predicted Hg0 removal is about 90percent with 5 ppm SCl2 or S2Cl2 and 40 g/m3 of flyash in flue gas. The combination of activated carbon and sulfur-chlorine compounds is an effective alternative. We estimate that co-injection of 3-5 ppm of SCl2 (or S2Cl2) with 2-3 Lb/MMacf of untreated Darco-KB is comparable in efficiency to the injection of 2-3 Lb/MMacf Darco-Hg-LH. Extrapolation of kinetic results also indicates that 90percent of Hg0 can be removed if 3 Lb/MMacf of Darco-KB pretreated with 3percent of SCl2 or S2Cl2 is used. Unlike gas phase reactions, NO exhibited little effect on Hg0 reactions with SCl2 or S2Cl2 on flyash or activated carbon. Mercuric sulfide was identified as one of the principal products of the Hg0/SCl2 or Hg0/S2Cl2 reactions. Additionally, about 8percent of SCl2 or S2Cl2 in aqueous solutions is converted to sulfide ions, which would precipitate mercuric ion from FGD solution.

  18. Macrokinetic relationships between anodic processes in chlorine electrolysis on ruthenium-titanium oxide anodes

    International Nuclear Information System (INIS)

    Effect of porosity on kinetics of the main (chlorine evolution) and side (oxygen evolution and anodic dissolution of ruthenium dioxide) reactions for chlorine electrolysis conditions has been analyzed. Making allowance for chlorine hydrolysis secondary reaction, the distribution of chlorine concentration, solution pH and current densities of the main and side processes over the porous anode depth, have been found. It is shown that solution acidification in the anode pores due to chlorine hydrolysis can bring about replacement of oxygen evolution and ruthenium dioxide dissolution side reactions toward the porous anode external sides thus affecting its selectivity and corrosion resistance

  19. Chlorination of organophosphorus pesticides in natural waters.

    Science.gov (United States)

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

    2008-05-01

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

  20. Unusual Intramolecular Hydrogen Transfer in 3,5-Di(triphenylethylenyl) BODIPY Synthesis and 1,2-Migratory Shift in Subsequent Scholl Type Reaction

    KAUST Repository

    Chua, Ming Hui

    2015-08-17

    The straightforward synthesis of 3,5-di(triphenylethylenyl) BODIPYs 1–3 from the condensation of 2-(triphenylethylenyl) pyrrole with aryl aldehydes are surprisingly found to produce side products that are hydrogenated at one of the two triphenylethylene substituents. It was also observed that the subsequent Scholl type reaction of 1 resulted in a “1,2-migratory shift” of one triphenylethylene substituent in addition to a ring closing reaction. Preliminary investigations, including DFT calculations and isolation of intermediates, were conducted to study these unusual observations on BODIPY chemistry.

  1. The 35th report on survey of the adverse reaction to radiopharmaceuticals. The 38th survey in 2012

    International Nuclear Information System (INIS)

    This survey was performed in order to investigate the incidence of adverse reactions to radiopharmaceuticals in FY2012 in Japan. It was based on responses to questionnaires sent to nuclear medicine institutions. The reply was obtained from 977 institutions among 1,251 to which the questionnaire had been sent. Eleven cases of adverse reactions were reported. A total of 1,060,526 radiopharmaceutical administrations was reported. The incidence of adverse reactions per 100,000 cases was 1.0. One case of defect products was reported, and the incidence of defect products per 100,000 cases was 0.1. (author)

  2. Chlorine Abundances in Cool Stars

    CERN Document Server

    Maas, Z G; Hinkle, K

    2016-01-01

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

  3. Water Treatment Technology - Chlorination.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

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

  4. Investigation of an Oscillation System in the Reaction of Chlorine Dioxide-Iodine-Malonic Acid-Sulfuric Acid%二氧化氯-碘-丙二酸-硫酸化学振荡体系的探讨

    Institute of Scientific and Technical Information of China (English)

    王芳; 施来顺

    2011-01-01

    The initial concentration of every reagent was changed in the chlorine dioxide-iodine-malonic acid-sulfuric acid oscillator in a closed system,and the system was investigated by determining the absorbance of I-3 with reaction time at 350 nm.As a result,the higher was the initial concentration of malonic acid,iodine or sulfuric acid,the bigger was the amplitude.Also,the number of oscillations became small.An opposite influence existed for chlorine dioxide.The oscillation occurred as long as the reactants mixed when the concentrations of components were comparatively high.However,the oscillation was preceded by a pre-oscillatory or induction period when the concentrations of components were relatively low.%对ClO2-I2-CH2(COOH)2-H2SO4化学振荡封闭体系,改变体系中各反应物的初始浓度,在350 nm处检测I3-的吸光度随反应时间的变化,结果发现丙二酸、碘及硫酸的初始浓度越高,二氧化氯的浓度越低,振荡的振幅越大,波数越少;当反应组分浓度较高时反应物一经混合振荡立即出现,没有诱导期,但当反应组分浓度较低时存在诱导期。

  5. Mutual separation characteristics for binary oxides Y2O3-Ln2O3(Ln = Sc,La,Nd,Sm) using stepwise selective chlorination-chemical vapor transport reaction mediated by vapor complexes KLnCl4

    Institute of Scientific and Technical Information of China (English)

    孙艳辉; 陈振飞; 王之昌

    2004-01-01

    Mutual separation characteristics for binary oxide mixtures Y2 O3-Sc2 O3, Y2 O3-La2 O3, Y2 O3-Nd2 O3and Y2 O3-Sm2 O3 using a stepwise selective chlorination-chemical vapor transport(SC-CVT) reaction mediated by vapor complexes KLnCl4 were investigated. The total transported yields of the chlorides produced from the oxide mixtures are in the order of NdCl3 >SmCl3 >LaCl3 >YCl3 >ScCl3 , the main deposition temperature of the chlorides is in the order of ScCl3 <YCl3 <SmCl3 <NdCl3 <LaCl3, and the largest separation factor values are 1 100 for Y . Sc,14.88 for Y : La, 9.86 for Y . Nd and 16.45 for Y . Sm in the temperature range from 1 000 K to 1 120 K, while 157.7 for La : Y, 51.6 for Nd : Y and 12.4 for Sm : Y in the temperature range from 1 200 K to 1 300 K, respectively. The results were discussed on the difference of KScCl4, KYCl4 and KLnCl4 and the selective chlorination of binary oxides at 800 K. Furthermore, the separation characteristics of vapor rare earth complex KLnCl4 were studied compared with those of LnAlnCl3n+3.

  6. In vitro substrate specificities of 3'-5' polymerases correlate with biological outcomes of tRNA 5'-editing reactions.

    Science.gov (United States)

    Long, Yicheng; Jackman, Jane E

    2015-07-22

    Protozoan mitochondrial tRNAs (mt-tRNAs) are repaired by a process known as 5'-editing. Mt-tRNA sequencing revealed organism-specific patterns of editing G-U base pairs, wherein some species remove G-U base pairs during 5'-editing, while others retain G-U pairs in the edited tRNA. We tested whether 3'-5' polymerases that catalyze the repair step of 5'-editing exhibit organism-specific preferences that explain the treatment of G-U base pairs. Biochemical and kinetic approaches revealed that a 3'-5' polymerase from Acanthamoeba castellanii tolerates G-U wobble pairs in editing substrates much more readily than several other enzymes, consistent with its biological pattern of editing.

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

    International Nuclear Information System (INIS)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ilić Ilija B.

    2003-01-01

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

  9. Dominance of binary dissipative reactions in nearly symmetric nucleus-nucleus collisions above 35 MeV/U

    International Nuclear Information System (INIS)

    Incomplete fusion or massive transfer mechanisms were invoked to explain the observed distributions of products, especially for heavy residues, for the nearly symmetric systems, 36Ar on 27Al from 55 to 95 MeV/u, and 64Zn on natTi, from 35 to 79 MeV/u. Charged products were detected in a nearly 4π geometry using two complementary multidetector systems. Lorentz invariant cross section maps plotted for different products show three sources for Z=1 and 2 particles: quasi-projectile, quasi-target and a third source, located at mid-rapidity. For heavier fragments, the mid-rapidity contribution vanishes. (K.A.)

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

    Science.gov (United States)

    Iqbal, Qais; Lubeck-Schricker, Maya; Wells, Emma; 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 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. PMID:27244552

  11. 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.

  12. (n,2n) and (n,3n) cross sections of neutron-induced reactions on 150Sm for En from threshold to 35 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Dashdorj, D; Mitchell, G; Kawano, T; Becker, J; Wu, C; Devlin, M; Fotiades, N; Nelson, R; Kunieda, S

    2009-03-16

    Cross-section measurements were made of prompt discrete {gamma}-ray production as a function of incident neutron energy (E{sub n} = 1 to 35 MeV) on a {sup 150}Sm sample fo 1550 mg/cm{sup 2} of Sm{sub 2}O{sub 3} enriched to 95.6% in {sup 150}Sm. Results are compared with enhanced Hauser-Feshbach model calculations including the pre-equilibrium reactions. Energetic neutrons were delivered by the Los Alamos Neutron Science Center facility. The prompt-reaction {gamma} rays were detected with the Compton-suppressed Germanium Array for Neutron Induced Excitations (GEANIE). Incident neutron energies were determined by the time-of-flight technique. Excitation functions for thirteen individual {gamma}-rays up to E{sub x} = 0.8 MeV in {sup 149}Sm and one {gamma}-ray transition between the first excited and ground state in {sup 148}Sm were measured. Partial {gamma}-ray cross sections were calculated using GNASH, an enhanced Hauser-Feshbach statistical nuclear reaction model code, and compared with the experimental results. The particle transmission coefficients were calculated with new systematic 'global' optical model potential parameters. The coupled-channel optical model based on the soft rotor model was employed to calculate the particle transmission coefficients. The pre-equilibrium part of the spin distribution in {sup 150}Sm was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK) and incorporated into the GNASH reaction model code. the partial cross sections for discrete {gamma}-ray cascade paths leading to the ground state in {sup 149}Sm and {sup 148}Sm have been summed (without double counting) to estimate lower limits for reaction cross sections. These lower limits are combined with Hauser-Feshbach model calculations to deduce the reaction channel cross sections. These reaction channel cross sections agree with previously measured experimental and ENDF/B-VII evaluations.

  13. Theoretical study on the reaction mechanism of chlorinated methylidyne radical with ozone%氯代次甲基与臭氧反应机理的理论研究

    Institute of Scientific and Technical Information of China (English)

    石从云; 胡威; 娄菲; 范淑珍

    2013-01-01

    The depletion of the ozone layer is one of the important environmental problems. The chlorinated methylidyne radical produced by UV photolysis of CFC in the stratosphere will consume the ozone. In order to clarify the ozone depletion mechanism by the radical, we employed quantum chemical calculations to study the reaction mechanisms of CCl radical with O3 on the doublet potential energy surface. The geometric structures of reactants, intermediates, transition states and products were optimized at the B3LYP/6-311G(d, p) level, and their vibration frequencies and energy values were obtained. Intrinsic reaction coordinate calculations at the same level were implemented to confirm the connections between transition states and intermediates. The detailed reaction pathways were made clear. It is found that the CCl + O3 reaction possesses five product channels:ClCO+O2, CO2+Cl+O, CO2+ClO, CO+O2+Cl, OCO2+Cl. Through the energy analysis of the stationary points on each reaction pathway, we can drawn the conclusion that the ClCO+O2 channel is the most feasible, CO2+Cl+O, CO2+ClO and OCO2+Cl are all secondary channels, the CO+O2+Cl channel is the least competitive. This research will provide theoretical basis for controlling the destruction of the ozone layer by the chlorinated methylidyne radical.%臭氧层损耗是人类面临的重要环境问题之一。平流层中氟氯烃类化合物受紫外线光解所产生的氯代次甲基会消耗臭氧。为了弄清该自由基消耗臭氧的机制,用量子化学计算的方法详细地研究了CCl+O3反应在二重态势能面上的反应机理。本文在B3LYP/6-311G(d, p)水平上优化了反应物、中间体、过渡态和产物的几何构型,得到了相应的振动频率和能量值,并在相同水平上用内禀反应坐标计算方法确认了过渡态和中间体之间的联系,理清了该反应详细的路径。研究发现CCl+O3反应有5种产物通道:ClCO+O2、CO2+Cl+O、CO2+ClO、CO+O2+Cl和OCO2+Cl

  14. Zirconia concentrate chlorination

    International Nuclear Information System (INIS)

    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)

  15. Production of Sigma{\\pm}pi?pK+ in p+p reactions at 3.5 GeV beam energy

    CERN Document Server

    Agakishiev, G; Belver, D; Belyaev, A; Berger-Chen, J C; Blanco, A; Boehmer, M; Boyard, J L; Cabanelas, P; Castro, E; Chernenko, S; Destefanis, T Christ M; Dohrmann, F; Dybczak, A; Epple, E; Fabbietti, L; Fateev, O; Finocchiaro, P; Fonte, P; Friese, J; Fröhlich, I; Galatyuk, T; Garzon, J A; Gernhäuser, R; Gilardi, C; Golubeva, M; Gonza'lez-Di'az, D; Guber, F; Gumberidze, M; Heinz, T; Hennino, T; Holzmann, R; Ierusalimov, A; Iori, I; Ivashkin, A; Jurkovic, M; Kämpfer, B; Kanaki, K; Karavicheva, T; Koenig, I; Koenig, W; Kolb, B W; Kotte, R; Kr'asa, A; Krizek, F; Krücken, R; Kuc, H; Kuehn, W; Kugler, A; Kurepin, A; Lalik, R; Lang, S; Lange, J S; Lapidus, K; Liu, T; Lopes, L; Lorenz, M; Maier, L; Mangiarotti, A; Markert, J; Metag, V; Michalska, B; Michel, J; Morinie're, E; Mousa, J; Müntz, C; Naumann, L; Otwinowski, J; Pachmayer, Y C; Palka, M; Parpottas, Y; Pechenov, V; Pechenova, O; Pietraszko, J; Przygoda, W; Ramstein, B; Reshetin, A; Rustamov, A; Sadovsky, A; Salabura, P; Schmah, A; Schwab, E; Siebenson, J; Sobolev, Yu G; Spataro, S; Spruck, B; Ströbele, H; Stroth, J; Sturm, C; Tarantola, A; Teilab, K; Tlusty, P; Traxler, M; Trebacz, R; Tsertos, H; Wagner, V; Weber, M; Wendisch, C; Wüstenfeld, J; Yurevich, S; Zanevsky, Y

    2012-01-01

    We study the production of Sigma^+-pi^+-pK^+ particle quartets in p+p reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES experiment at GSI. This report evaluates the contribution of resonances like Lambda(1405$, Sigma(1385)^0, Lambda(1520), Delta(1232), N^* and K^*0 to the Sigma^+- pi^-+ p K+ final state. The resulting simulation model is compared to the experimental data in several angular distributions and it shows itself as suitable to evaluate the acceptance corrections properly.

  16. Evolution of Structure-Reactivity Correlations for the Hydrogen Abstraction Reaction by Hydroxyl Radical and Comparison with that by Chlorine Atom

    Energy Technology Data Exchange (ETDEWEB)

    Poutsma, Marvin L [ORNL

    2013-01-01

    A structure-reactivity correlation for the reaction (HO + HCR3 HOH + CR3 ) has been formulated: log k298(per H) = 0.000630 rH2 0.151 rH 1.056 F 1.053 R 21.26 (r2 = 0.885; n = 70; mean unsigned deviation = 0.29 log units), where rH is the reaction enthalpy and F and R represent the dissection of Hammett s para constant into its field/inductive and resonance effects, and compared for the analogous case for Cl (ref 1). Although more exothermic, the dependence of HO on rH is somewhat greater than Cl . However the dependence on F and R is much less, suggestive of less charge separation in the transition state for the less electronegative HO . The range of k(OH) is significantly less than that of Cl , i.e., it is less dependent on substrate structure. Yet a cross-over exists such that k(Cl) > k(HO) predominates for more reactive cases whereas k(Cl) < k(OH) characterizes the less reactive. The Arrhenius parameters reveal that this cross-over results from a change in {E(Cl) E(OH)} from negative to positive. In contrast, whereas the A factors for both increase significantly as reactivity increases, {A(Cl) / A(OH)} always exceeds unity.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

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

  18. Formation of chlorinated lipids post-chlorine gas exposure.

    Science.gov (United States)

    Ford, David A; Honavar, Jaideep; Albert, Carolyn J; Duerr, Mark A; Oh, Joo Yeun; Doran, Stephen; Matalon, Sadis; Patel, Rakesh P

    2016-08-01

    Exposure to chlorine (Cl2) gas can occur during accidents and intentional release scenarios. However, biomarkers that specifically indicate Cl2 exposure and Cl2-derived products that mediate postexposure toxicity remain unclear. We hypothesized that chlorinated lipids (Cl-lipids) formed by direct reactions between Cl2 gas and plasmalogens serve as both biomarkers and mediators of post-Cl2 gas exposure toxicities. The 2-chloropalmitaldehyde (2-Cl-Pald), 2-chlorostearaldehyde (2-Cl-Sald), and their oxidized products, free- and esterified 2-chloropalmitic acid (2-Cl-PA) and 2-chlorostearic acid were detected in the lungs and plasma of mouse and rat models of Cl2 gas exposure. Levels of Cl-lipids were highest immediately post-Cl2 gas exposure, and then declined over 72 h with levels remaining 20- to 30-fold higher at 24 h compared with baseline. Glutathione adducts of 2-Cl-Pald and 2-Cl-Sald also increased with levels peaking at 4 h in plasma. Notably, 3-chlorotyrosine also increased after Cl2 gas exposure, but returned to baseline within 24 h. Intranasal administration of 2-Cl-PA or 2-Cl-Pald at doses similar to those formed in the lung after Cl2 gas exposure led to increased distal lung permeability and inflammation and systemic endothelial dysfunction characterized by loss of eNOS-dependent vasodilation. These data suggest that Cl-lipids could serve as biomarkers and mediators for Cl2 gas exposure and toxicity. PMID:27324796

  19. Extension of Structure-Reactivity Correlations for the Hydrogen Abstraction Reaction to the Methyl Radical and Comparison to the Chlorine Atom, Bromine Atom, and Hydroxyl Radical.

    Science.gov (United States)

    Poutsma, Marvin L

    2016-07-01

    Recently, we presented structure-reactivity correlations for the gas-phase rate constants for hydrogen abstraction from sp(3)-hybridized carbon by three electrophilic radicals (X(•) + HCR3 → XH + (•)CR3; X = Cl(•), HO(•), and Br(•)); the reaction enthalpy effect was represented by the independent variable ΔrH and the "polar effect" by the independent variables F and R, the Hammett-Taft constants for field/inductive and resonance effects. Here we present a parallel treatment for the less electronegative CH3(•). In spite of a limited and scattered database, the resulting least-squares fit [log k437(CH3(•)) = -0.0251(ΔrH) + 0.96(ΣF) - 0.56(ΣR) - 19.15] was modestly successful and useful for initial predictions. As expected, the polar effect appears to be minor and its directionality, i.e., the "philicity" of CH3(•), may depend on the nature of the substituents. PMID:27266850

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

    OpenAIRE

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

    2000-01-01

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

  1. 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.

  2. Effect of sulfur dioxide on indium (3) oxide chlorination

    International Nuclear Information System (INIS)

    On the basis of thermodynamic calculations and kinetic investigations, it is established that in the temperature range from 550 to 800 deg C in the In2O3-Cl2-SO2 system coupled reactions of InCl3 and In2(SO4)3 formation accompanying by further In2(SO4)3 chlorination with gaseous chlorine are main processes, SO2 accelerates considerably In2O3 chlorination at a temperature below 800 deg C, its influence on the process of chloride sublimation at a temperature higher than 800 deg C is not so noticeable

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  4. Chlorine dioxide as an oxidant for organoboron compounds

    International Nuclear Information System (INIS)

    Practicability of using chlorine dioxide aqueous solution as an oxidant for terpene organoboron compounds prepared by hydroborating (+)α-pinene (1) and (-)β-pinene (2) is studied. By the methods of IR spectroscopy and 13C NMR it is shown that products of 1 and 2 oxidation are (-)-isopinocampheol and (-)-cis-myrtanol, which are formed with a high yield. In terms of its efficiency chlorine dioxide is no worse than hydrogen peroxide in reactions of organoboric compounds oxidation

  5. Research on the Preparation of Crosslinked Starch Chlorinated with Sodium Hypochlorite

    Institute of Scientific and Technical Information of China (English)

    LiangYin; ZhuZhi-feng

    2003-01-01

    Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with form-aldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.

  6. Research on the Preparation of Crosslinked Starch Chlorinated with Sodium Hypochlorite

    Institute of Scientific and Technical Information of China (English)

    Liang Yin; Zhu Zhi-feng

    2003-01-01

    Optimization of reaction variables such as catalyst type and amount, reaction temperature and time, formaldehyde amount, and oxidation extent of starch was studied for the crosslinking reaction of chlorinated cornstarch with formaldehyde. The reaction was carried out in aqueous suspension dispersed granular chlorinated cornstarch. Catalysts such as hydrochloric acid, sulfuric acid, and nitric acid were individually evaluated. The results show that the type and amount of the inorganic acid, formaldehyde amount, and oxidation extent of the chlorinated starch strongly affect the reaction efficiency. Hydrochloric acid shows the best catalyst effect on the reaction. Increasing the amount of the catalyst favourably raises the reaction efficiency. It is also demonstrated that the reaction efficiency is enhanced with the decrease of the oxidation extent of granular chlorinated starch.

  7. Thermal Behavior, Non-isothermal Decomposition Reaction Kinetics of Copper(Ⅱ) Salt of 4-Hydroxy-3,5-dinitropyridine and Its Application in Propellant

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei; ZHAO Feng-qi; LUO yang; HU Rong-zu; GAO Sheng-li; ZHENG Yu-mei; DENG Min-hi; GAO Yin

    2005-01-01

    The thermal behavior and kinetic parameters of the major exothermic decomposition reaction of the title compound in a temperature-programmed mode were studied by means of TG-DTG and DSC. The critical temperature of thermal explosion was calculated. The effect of the title compound on the combustion characteristic of composition modifier double base propellant containing RDX was explored with a strand burner. The results show that the kinetic model function in differential forms, the apparent activation energy(Ea) and the pre-exponential factor(A) of the major exothermic decomposition reaction are 3(1-α)[-ln(1-α)]2/3, 190.56 kJ/mol and 1013.39 s-1, respectively. The critical temperature of thermal explosion of the compound is 353.08 ℃. The kinetic equation of the major exothermic decomposition process of the title compound at 0.1 MPa could be expressed as dα/dT=1014.65(1-α)[-ln(1-α)]2/3 e-2.2920×104/T. As an auxiliary catalyzer, the title compound can help the main catalyzer of lead salt of 4-hydroxy-3,5-dinitropyridine to accelerate the burning rate and reduce the pressure exponent of RDX-CMDB propellant.

  8. Hydrogen-chlorine fuel cell for production of hydrochloric acid and electric power : chlorine kinetics and cell design

    OpenAIRE

    Thomassen, Magnus Skinlo

    2005-01-01

    This thesis work is the continuation and final part of a joint project between the Department of Materials Technology, NTNU and Norsk Hydro Research Center in Porsgrunn, looking at the possibility of using fuel cells for production of hydrogen chloride and electric power. The experimental work encompass an evaluation of three hydrogen - chlorine fuel cell design concepts, development and implementation of a mathematical fuel cell model and a kinetic study of the chlorine reduction reaction. T...

  9. Chlorination and Carbochlorination of Cerium Oxide

    International Nuclear Information System (INIS)

    The chlorination and carbochlorination of cerium oxide were studied by thermogravimetry under controlled atmosphere (TG) in the 7000C 9500C 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 8000C.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 8500C-9500C 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 7000C.This reaction is completed in one step controlled by mass transfer with an apparent activation energy of 56 to 5 kJ/mole in the 8500C-9500C temperature range

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  12. New ORP/pH based control strategy for chlorination and dechlorination of wastewater: pilot scale application.

    Science.gov (United States)

    Kim, H; Kwon, S; Han, S; Yu, M; Kim, J; Gong, S; Colosimo, M F

    2006-01-01

    Due to its efficiency and low capital demands, chlorination has been widely used for disinfection in many wastewater treatment plants. Since the oxidation power of free chlorine is bigger than combined chlorines which are formed from the reaction between chlorine and reducing agents in water (especially, NH4+ and organic nitrogen), for effective disinfection, excess amount of chlorine is added until all the reducing agents are oxidized and free chlorine is available. After chlorination, chlorine residues in wastewater are usually reduced with SO2 or sulfites before the treated wastewater is discharged, since they are toxic to aquatic life. Addition of excess amount of SO2 or sulfite should be avoided. Otherwise, they consume dissolved oxygen in a river or stream and may have adverse impact on the aquatic life. Determination of wastewater chlorine demand and of sulfite dosages for dechlorination has been a challenge to WWTP operators, due to the dynamic characteristics of wastewater. Recently, a new ORP/pH based approach to determine chlorine demand and sulfite dosage was proposed. The method utilizes significant points occurring on the pH and ORP profiles during chlorination and dechlorination titrations. In this study, the proposed automatic titration system has been implemented into a control system to optimize chlorine and sulfite doses for a pilot scale chlorination/dechlorination system. In short, the disinfection system with the pH/ORP based controller showed very successful results; complete inactivation of total coliforms, and almost zero residual chlorines and high DO in its effluent. PMID:16749451

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

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

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

    Adenosine triphosphate (ATP) analysis is a cultivation-independent alternative method for the determination of bacterial viability in both chlorinated and non-chlorinated water. Here we investigated the behavior and stability of ATP during chlorination in detail. Different sodium hypochlorite doses (0-22.4 mg-Cl2 L(-1); 5 min exposure) were applied to an Escherichia coli pure culture suspended in filtered river water. We observed decreasing intracellular ATP with increasing chlorine concentrations, but extracellular ATP concentrations only increased when the chlorine dose exceeded 0.35 mg L(-1). The release of ATP from chlorine-damaged bacteria coincided with severe membrane damage detected with flow cytometry (FCM). The stability of extracellular ATP was subsequently studied in different water matrixes, and we found that extracellular ATP was stable in sterile deionized water and also in chlorinated water until extremely high chlorine doses (≤11.2 mg-Cl2 L(-1); 5 min exposure). In contrast, ATP decreased relatively slowly (k = 0.145 h(-1)) in 0.1 μm filtered river water, presumably due to degradation by either extracellular enzymes or the fraction of bacteria that were able to pass through the filter. Extracellular ATP decreased considerably faster (k = 0.368 h(-1)) during batch growth of a river water bacterial community. A series of growth potential tests showed that extracellular ATP molecules were utilized as a phosphorus source during bacteria proliferation. From the combined data we conclude that ATP released from bacteria at high chlorine doses could promote bacteria regrowth, contributing to biological instability in drinking water distribution systems. PMID:27295623

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

    Science.gov (United States)

    Nescerecka, Alina; Juhna, Talis; Hammes, Frederik

    2016-09-15

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

  16. Study of the nuclear spin-orbit interaction by performing the transfer reaction 36S(d,p)37S and 34Si(d,p)35Si

    International Nuclear Information System (INIS)

    The spin-orbit interaction depends on the spin orientation of the nucleons with respect to their angular momenta as well as on the derivative of the nuclear density. Even though this density dependence is used in all mean field model, it has never been tested yet due to the lack of data. We propose an original method to test this density dependence by comparing a bubble nucleus (34Si) to a normal nucleus (36S). The 34Si exhibits a central density which is depleted by a factor of two which induces a non-zero central density derivative and should change the strength of the spin orbit interaction for the inner orbits such as the p orbits (L=1). By performing (d,p) transfer reactions with 36S and 34Si beams, the p(3/2) and p(1/2) spin orbit splitting can be inferred for these nuclei. Depending on the models, the spin-orbit splitting varies from 7% (VlowK interaction) up to 70% (Relativistic mean field approach). Beams of 36S and 34Si, produced at the LISE spectrometer at 20 A.MeV, were impinged onto a CD2 target. Tracking the beam particles was achieved using 2 xy beam tracking gas detectors. Protons emitted were detected by 4 multi-segmented Si detectors (MUST2) placed at backwards angles. Gammas issued from the excited states decay were detected in the 4 EXOGAM segmented Germanium detectors. Transfer like nuclei were identified with an ionization chamber and a plastic detector. The excitation energy spectra of the 37S and 35Si are determined up to about 7 MeV. Spectroscopic factors and energies of p and f states are derived for the first time in 35Si. The two nuclei show strong similarity for the f spin-orbit partners, whereas the p(3/2) - p(1/2) energy gap is reduced by 55%. (author)

  17. Removal of carbamazepine in aqueous solutions through solar photolysis of free available chlorine.

    Science.gov (United States)

    Yang, Bin; Kookana, Rai S; Williams, Mike; Du, Jun; Doan, Hai; Kumar, Anupama

    2016-09-01

    Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investigated by using solar photolysis combined with free available chlorine (FAC). The combination of chlorination with simulated or natural sunlight markedly enhanced removal of CBZ in 10 mM phosphate buffer solution (pH 7.0) and river water (pH 7.0) compared with sunlight or FAC alone. Further analysis indicated that the observed enhancements in CBZ removal can be attributed to the in situ hydroxyl radical (HO) and ozone (O3) production during FAC photolysis. During 70 min simulated sunlight photolysis combined with FAC treatment, HO reaction contributed to 35.8% removal of CBZ and O3 reaction contributed to 40.6% removal, while only 5.3% of CBZ was removed by HOCl reaction. The oxidation products of CBZ, epoxide CBZ, 10,11-dihydro-10,11-dihydroxy CBZ, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) and 4-aldehyde-9-acridone, were mainly formed from the HO and O3 attack at the double bond on the central heterocyclic ring of CBZ. Formation of these oxidation products did not cause any increase or decrease in toxicity to microbial species tested through Microbial Assay for Toxicity Risk Assessment (MARA). The initial FAC concentration and pH had a major influence on the removal process of CBZ during FAC photolysis, while temperature had a minor effect only. The combination of chlorination with natural sunlight could provide an effective approach for removal of CBZ and other contaminants during water treatment. PMID:27232985

  18. 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)

    The aluminium chloride is synthesized by direct chlorination of aluminium, in agreement with the following reaction: Al(s) + 3/2 Cl2 AlCl3 (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 2000 and 5000C.(b) Chlorination of the same alloy in chlorine flow between 1500 and 4000C.In the sealed systems, the hexahydrated aluminium trichloride predominated over the anhydrous form. For pressures lower than 14 Kpa and temperatures under 2500C, 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 1000C, for all the thermal treatments. The waste was composed by CrCl3 and AlCl3.6H2O.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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  20. Modeling of residual chlorine in water distribution system

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen Lianzhong [Academia Sinica, Beijing, BJ (China). Inst. of Atomic Energy; 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 {mu}gCl/g for a 2.0 g sample. The precision was about 2.5% (relative standard deviation) for samples with chlorine content of 70 {mu}g/g level. The method is also usable for coal samples. (author).

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

    International Nuclear Information System (INIS)

    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)

  3. Revisiting the thermochemistry of chlorine fluorides

    CERN Document Server

    Sánchez, H R

    2016-01-01

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

  4. 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.

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

    International Nuclear Information System (INIS)

    This study investigated disinfection methods including chlorination, ultraviolet (UV) irradiation and sequential UV/chlorination treatment on the inactivation of antibiotic resistance genes (ARGs). ARGs including sul1, tetX, tetG, intI1, and 16S rRNA genes in municipal wastewater treatment plant (MWTP) effluent were examined. The results indicated a positive correlation between the removal of ARGs and chlorine dosage (p = 0.007–0.014, n = 6),as well as contact time (p = 0.0001, n = 10). Greater free chlorine (FC) dosage leads to higher removal for all the genes and the maximum removal (1.30–1.49 logs) could be achieved at FC dosage of 30 mg L−1. The transformation kinetic data for ARGs removal (log C0 / C) followed the second-order reaction kinetic model with FC dosage (R2 = 0.6829–0.9999) and contact time (R2 = 0.7353–8634), respectively. Higher ammonia nitrogen (NH3–N) concentration was found to lead to lower removal of ARGs at the same chlorine dosage. When the applied Cl2:NH3–N ratio was over 7.6:1, a significant reduction of ARGs (1.20–1.49 logs) was achieved. By using single UV irradiation, the log removal values of tetX and 16Ss rRNA genes were 0.58 and 0.60, respectively, while other genes were 0.36–0.40 at a fluence of 249.5 mJ cm−2, which was observed to be less effective than chlorination. With sequential UV/chlorination treatment, 0.006 to 0.31 log synergy values of target genes were observed under different operation parameters. - 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 NH3–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

  6. 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

    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......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......) concentrations remained low (b1 μg/L) and ethene was not observed. The correlated shift of carbon and chlorine isotope ratios of cDCE by 8 and 3.9‰, respectively, the detection of Dehaloccocides sp genes, and strongly reducing conditions in this zone provide strong evidence for reductive dechlorination of c...

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

  8. Chlorination of commercial molybdenite concentrate in a fluidized bed reactor

    Science.gov (United States)

    Nair, K. U.; Sathiyamoorthy, D.; Bose, D. K.; Sundaresan, M.; Gupta, C. K.

    1987-06-01

    Studies on recovery of molybdenum from commercial grade molybdenite using the technique of fluidized bed chlorination in the presence of oxygen are presented. Molybdenum recovery above 99 pct at a chlorine utilization efficiency of 84 pct has been achieved for a fluidizing gas flow-rate of 3 L/min of the gases Cl2, O2, and N2 mixed in the proportion of 2∶5∶23, respectively, at 300 °C. The investigations on kinetics showed that the overall oxychlorination reaction is controlled by chemical reaction and is of first order with respect to particle surface area.

  9. The chlorination of cooling water

    International Nuclear Information System (INIS)

    After reviewing the means of fighting biological pollution of cooling water circuits in nuclear power stations, the authors describe the chlorination treatment methods used by EDF. This deals with the massive shock chlorination of the cooling towers and the continuous low-level chlorination of coastal nuclear power stations. In both areas, the Research and Development Board of EDF has carried out and encouraged research with the aim of improving circuit protection, while still protecting the aquatic eco-system against damage that might be caused by waste chlorinated water

  10. Variation in assimilable organic carbon formation during chlorination of Microcystis aeruginosa extracellular organic matter solutions.

    Science.gov (United States)

    Sun, Xingbin; Yuan, Ting; Ni, Huishan; Li, Yanpeng; Hu, Yang

    2016-07-01

    This study investigated the chlorination of Microcystis aeruginosa extracellular organic matter (EOM) solutions under different conditions, to determine how the metabolites produced by these organisms affect water safety and the formation of assimilable organic carbon (AOC). The effects of chlorine dosages, coagulant dosage, reaction time and temperature on the formation of AOC were investigated during the disinfection of M.aeruginosa metabolite solutions. The concentration of AOC followed a decreasing and then increasing pattern with increasing temperature and reaction time. The concentration of AOC decreased and then increased with increasing chlorination dosage, followed by a slight decrease at the highest level of chlorination. However, the concentration of AOC decreased continuously with increasing coagulant dosage. The formation of AOC can be suppressed under appropriate conditions. In this study, chlorination at 4mg/L, combined with a coagulant dose of 40mg/L at 20°C over a reaction time of 12hr, produced the minimum AOC. PMID:27372113

  11. Quantitation of 35S promoter in maize DNA extracts from genetically modified organisms using real-time polymerase chain reaction, part 2: interlaboratory study.

    Science.gov (United States)

    Feinberg, Max; Fernandez, Sophie; Cassard, Sylvanie; Bertheau, Yves

    2005-01-01

    The European Committee for Standardization (CEN) and the European Network of GMO Working Laboratories have proposed development of a modular strategy for stepwise validation of complex analytical techniques. When applied to the quantitation of genetically modified organisms (GMOs) in food products, the instrumental quantitation step of the technique is separately validated from the DNA extraction step to better control the sources of uncertainty and facilitate the validation of GMO-specific polymerase chain reaction (PCR) tests. This paper presents the results of an interlaboratory study on the quantitation step of the method standardized by CEN for the detection of a regulatory element commonly inserted in GMO maize-based foods. This is focused on the quantitation of P35S promoter through using the quantitative real-time PCR (QRT-PCR). Fifteen French laboratories participated in the interlaboratory study of the P35S quantitation operating procedure on DNA extract samples using either the thermal cycler ABI Prism 7700 (Applied Biosystems, Foster City, CA) or Light Cycler (Roche Diagnostics, Indianapolis, IN). Attention was focused on DNA extract samples used to calibrate the method and unknown extract samples. Data were processed according to the recommendations of ISO 5725 standard. Performance criteria, obtained using the robust algorithm, were compared to the classic data processing after rejection of outliers by the Cochran and Grubbs tests. Two laboratories were detected as outliers by the Grubbs test. The robust precision criteria gave values between the classical values estimated before and after rejection of the outliers. Using the robust method, the relative expanded uncertainty by the quantitation method is about 20% for a 1% Bt176 content, whereas it can reach 40% for a 0.1% Bt176. The performances of the quantitation assay are relevant to the application of the European regulation, which has an accepted tolerance interval of about +/-50%. These data

  12. ANALYSIS OF NASAL TISSUE FOR BIOMARKERS OF CHLORINE EXPOSURE

    Science.gov (United States)

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

  13. Theoretical Study on the Reaction of Chlorine Trifluoride Oxide with Propylene Oxide by Density Functional Theory%ClF3O和环氧丙烷反应的理论研究

    Institute of Scientific and Technical Information of China (English)

    闫华; 刘志勇; 史茂盛; 罗永锋; 颜澎; 贡雪东

    2015-01-01

    应用密度泛函理论对 ClF3 O 和环氧丙烷的反应机理进行了研究。在 B3PW91/6-31++G(d ,p )水平上优化了各驻点(反应物、中间体、过渡态和产物)的几何构型,并计算了它们的振动频率和零点振动能。采用 CCSD(T)/6-31++G(d ,p )//B3PW91/6-3l++G(d ,p )单点能计算方法求得各物质的能量,并做零点能校正。计算结果表明,ClF3 O 与 C3 H 6 O 可经过不同的反应路径,引发 C3 H 5 O 自由基和 ClOF2自由基生成环氧丙醇和三氟化氯,其中,位于 ClF3 O 周向位置的 F 原子与 C3 H 6 O 的 C(7)上与 CH 3异侧的 H(9)原子结合的活化能最低,仅15.63 kJ/mo1;ClF3 O 与 C3 H 6 O 反应生成的 C3 H 5 O 自由基和 ClOF2自由基继续反应,经过不同反应路径生成 C3 H 4 O、ClOF 和 HF,其中,ClOF2中的 F 原子和 C3 H 5 O 中的 H(2)或 H(4)原子结合是无能垒的过程。整个反应的主要路径为 C3 H 6 O+ClF3→O→TS12 P4(C3 H 5 O+HF+ClOF2→) P12(CH 2 CHCHO+2 HF+ClOF)。%Using density functional theory (DFT),the reaction of chlorine trifluoride oxide (ClF3 O)with propylene oxide (C3 H 6 O)was studied.At the B3PW91/6-31++G(d ,p )level,geometries of all species (re-actants,transition states and products)were optimized,and the vibrational frequencies and zero point vibration-al energies (ZPVE)were calculated.The energies of all species were refined with CCSD(T)/6-31++G(d,p)//B3PW91/6-31++G(d,p)method and ZPVE correction.The calculated results suggest that the initial reaction has various pathways to yield the main products of C3 H 5 O and ClOF2 radicals,and C3 H 6 O 2 and ClF3 mole-cules.The reactions of C3 H 5 O and ClOF2 radicals have different pathways to yield the main products of C3 H 4 O,ClOF and HF molecules.The main reaction channel is C3 H 6 O+ClF3→O→TS12 P4 (C3 H 5 O+HF+ClOF2→) P12 (CH 2 CHCHO+2 HF+ClOF).P4 is produced by C3 H 6 O and ClF3 O via TS12 with a low barrier of 1 5.63 kJ/mol,and P12 can be formed from P4 through a barrierless

  14. Application of gas chromatography to the study of the chemical effects produced by the radiolysis and the 35Cl(n,p)35S reaction on the CCl4

    International Nuclear Information System (INIS)

    In this work the gas radiochromatography, which is essential in the hot atom chemistry is used. By means of this technique the chemical effects of the 35Cl(n,p)35S, and the radiolysis of liquid CCl4 were studied. The samples of liquid CCl4 were capsulated in cuarzo bulbs and were deaereated by several cycles of freeze and pumping in a vacuum line. The sample's irradiation was made in the Triga Mark III Salazar reactor with an approximated flux of 1012n-cm2-s-1 during ten hours. The sample's analysis was made using a gas radiochromatographer composed of a gas chromatographer, proportional flux detector and an adequate electronic system. In this form were obtained the radiochromatographics of the 35S labelled compounds possibly formed by hot atom chemistry and at the same time the hexachloroetane formed by the secondary radiolytic effect of the ionizing radiation on the CCl4 was identified. (author)

  15. Photostability of different chlorine photosensitizers

    International Nuclear Information System (INIS)

    In this paper, we report the photodegradation of three different chlorine photosensitizers (Photoditazine®, Radachlorin®, and Foscan®). The photosensitizer degradation was analyzed by changes in the fluorescence spectrum during illumination. The rate of fluorescence variation was normalized to the solution absorption and the photon energy resulting in the determination of the necessary number of photons to be absorbed to induce photosensitizer photodegradation. The parameter for rate of the molecules decay, the photon fluence rate and optical properties of the solution allow us to determine the photosensitizer stability in solution during illumination. The results show that the order of susceptibility for photodegradation rate is: Radachlorin® < Photoditazine® < Foscan®. This difference in the photodegradation rate for Foscan can be explained by the high proportion of aggregates in solution that inhibit the photo-oxidative process that impede the singlet oxygen formation. We hypothesize that there is a correlation between photodegradation rate and photodynamic efficacy witch is governed by the singlet oxygen formation responsible for the most relevant reaction of the cell death photodynamic induction. Then its is important to know the photostability of different types of drugs since the photodegradation rate, the photodegradation as well as the photodynamic efficacy are strong correlated to the oxygen concentration in the tissue

  16. Inactivation of Chironomid Larvae with Chlorine Dioxide and Chlorine

    Institute of Scientific and Technical Information of China (English)

    SUN Xin-bin; CUI Fu-yi

    2008-01-01

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

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

    Science.gov (United States)

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

    2014-05-15

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

  18. The chlorine isotope fingerprint of the lunar magma ocean

    OpenAIRE

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

    2015-01-01

    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 a...

  19. VARIATIONS IN ISOTOPIC COMPOSITIONS OF CHLORINE IN EVAPORATION-CONTROLLED SALT LAKE BRINES OF QAIDAM BASIN,CHINA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The variations in the isotopic compositions of chlorine in evaporation-controlled saline lake brines were determined by using an improved procedure for precise measurement of chlorine isotopes based on Cs2Cl+ ion by thermal ionization mass spectrometry. The results showed that variation in δ37Cl values in these evaporation-controlled brines are attributable to evaporation of brine accompanied by the deposition of saline minerals. The isotopic fractionation of chlorine between the deposited saline mineral and the co-existing brine caused the variation of δ37Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of 37Cl in the solid phase relative to 35Cl. The reverse isotopic fractionation of chlorine in which 35Cl is enriched in the solid phase, was observed to some extent during quick deposition under laboratory conditions as well as in nature. The mechanism of isotopic fractionation of chlorine during evaporation deposition was studied.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-15

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

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

    International Nuclear Information System (INIS)

    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 Cl2–N2 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% Al2O3 (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 Cl2 atmosphere of the MgO–Al2O3 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

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

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

    Science.gov (United States)

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

    2016-07-01

    For successful wastewater reclamation, advanced oxidation processes have attracted attention for elimination of emerging contaminants. In this study, the synergistic treatment with UV irradiation and chlorine (UV/chlorine) was used to degrade carbamazepine (CBZ). Neither UV irradiation alone nor chlorination alone could efficiently degraded CBZ. UV/chlorine oxidation showed a significant synergistic effect on CBZ degradation through generation of radical species (OH and Cl), and this process could be well depicted by pseudo first order kinetic. The degradation rate constants (kobs,CBZ) of CBZ increased linearly with increasing UV irradiance and chlorine dosage. The degradation of CBZ by UV/chlorine in acidic solutions was more efficient than that in basic solutions mainly due to the effect of pH on the dissociation of HOCl and OCl(-) and then on the quantum yields and radical species quenching of UV/chlorine. When pH was increased from 5.5 to 9.5, the rate constants of degradation of CBZ by OH decreased from 0.65 to 0.14 min(-1) and that by Cl decreased from 0.40 to 0.11 min(-1). The rate constant for the reaction between Cl and CBZ was 5.6 ± 1.6 × 10(10) M(-1) s(-1). Anions of HCO3(-) (1-50 mM) showed moderate inhibition of CBZ degradation by UV/chlorine, while Cl(-) did not. UV/chlorine could efficiently degrade CBZ in wastewater treatment plant effluent, although the degradation was inhibited by about 30% compared with that in ultrapure water with chlorine dosage of 0.14-0.56 mM. Nine main oxidation products of the CBZ degradation by UV/chlorine were identified using the HPLC-QToF MS/MS. Initial oxidation products arose from hydroxylation, carboxylation and hydrogen atom abstraction of CBZ by OH and Cl, and were then further oxidized to generate acylamino cleavage and decarboxylation products of acridine and acridione. PMID:27105033

  4. 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...

  5. Materials compatibility during the chlorination of molten CaCl2 . CaO salts

    International Nuclear Information System (INIS)

    As part of our effort to develop a semicontinuous PuO2 reduction process, we are investigating promising materials for containing a 9000C molten CaCl2 . CaO chlorination reaction. We want the material to contain this reaction and to be reusable. We tested candidate materials in a simulated salt (no plutonium) using anhydrous HCl as the chlorinating agent. Data are presented on the performance of 36 metals and alloys, 9 ceramics, and 3 coatings

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

    DEFF Research Database (Denmark)

    Stoianov, Ivan; Aisopou, Angeliki

    2014-01-01

    This paper describes a simulation framework for the scale-adaptive hydraulic and chlorine decay modelling under steady and unsteady-state flows. Bulk flow and pipe wall reaction coefficients are replaced with steady and unsteady-state reaction coefficients. An unsteady decay coefficient is defined...... and these demonstrate that the dynamic hydraulic conditions have a significant impact on water quality deterioration and the rapid loss of disinfectant residual. © 2013 The Authors....

  7. Axially Dissymmetric Chiral ( R ) -N, N′-Bis (2-hydroxy-3,5-ditert-butyl-arylmethyl)-1, 1′-binaphthalene-2,2′-diamine as Chiral Ligands in the Reaction of Diethylzinc to Aldehydes

    Institute of Scientific and Technical Information of China (English)

    SHI,Min(施敏); DUAN,Wei-Liang(段伟良); RONG,Guo-Bin(荣国斌)

    2002-01-01

    Chiral ligand (R) -N, N′-Bis(2-hydroxy-3,5-di- tert-butyl-arylmethyl)-1, 1′-binaphthalene-2, 2′-diamine derived from the reduction of Schiff base (R)-2,2′-bis (3,5-di-tert-butyl-2-hydroxybenzylideneamino)-1, 1′-binaphthyl with LIAlH4 is fairly effective in the asymmetric addition reaction of diethylzinc to aldehydes by which good yields (46%-94%) of the corresponding sec-alcohols can be obtained in moderate ee (51%-79% ) with R configuration for a variety of aldehydes.

  8. Chlorination of pyrene in soil components with sodium chloride under xenon irradiation

    International Nuclear Information System (INIS)

    It was previously reported that chlorinated pyrenes (1-chloropyrene and dichloropyrene) were produced from pyrene in soil under sunlight irradiation. It was suggested that pyrene reacted with chlorine ion under sunlight. In this work, the formation of chlorinated pyrenes is investigated on 9 metallic oxides as soil components with pyrene and sodium chloride under xenon lamp irradiation. The chlorinated pyrenes as the reaction products were extracted with benzene:ethanol (4:1), and analyzed by GC/MS (SIM). The chlorinated pyrenes were produced in high amounts on 5 metallic oxides [silicon dioxides (quartz, silicic anhydride and silica gel forms) and titanium dioxides (rutile and anatase forms)] and in small amounts in 3 sorts of metallic oxides (aluminium oxide, magnesium oxide and ferric oxide), whereas they were not produced on calcium oxide. It was found that the yields of chlorinated pyrenes depended on the amounts of pyrene and chlorine ions in metallic oxides. In silicon dioxides, the yields of chlorinated pyrenes increased as the irradiation time was extended. In the titanium dioxides, the yields of chlorinated pyrenes had a peak at 0.5 – 1 hours irradiation of xenon lamp, and decreased as the irradiation time elapsed. (author)

  9. Determination of intrinsic kinetics parameters for MoO{sub 3} chlorination with Cl{sub 2} gas between 798 and 873 K

    Energy Technology Data Exchange (ETDEWEB)

    De Micco, G., E-mail: demiccog@cab.cnea.gov.ar [Comision Nacional de Energia Atomica (C.N.E.A.), Avenida Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Universidad Nacional de Cuyo, Instituto Balseiro, Avenida Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Carignan, M. [Comision Nacional de Energia Atomica (C.N.E.A.), Avenida Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Canavesio, C.A. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Bohe, A.E. [Comision Nacional de Energia Atomica (C.N.E.A.), Avenida Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Universidad Nacional del Comahue, Centro Regional Universitario Bariloche, 8400 San Carlos de Bariloche (Argentina)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Kinetics of chlorination of MoO{sub 3} was studied by thermogravimetry. Black-Right-Pointing-Pointer The starting temperature for the reaction is determined at about 770 K. Black-Right-Pointing-Pointer An average activation energy of 211 kJ mol{sup -1} for the chlorination was determined. Black-Right-Pointing-Pointer A reaction order of 1 with respect to chlorine partial pressure was obtained. Black-Right-Pointing-Pointer A complete reaction rate equation was formulated for two MoO{sub 3} sample morphologies. - Abstract: In this work the kinetics of the chlorination of molybdenum trioxide has been studied by thermogravimetry between 798 and 873 K. The starting temperature for the reaction of MoO{sub 3} with chlorine is determined at about 770 K. The influence of gaseous flow rate, sample mass, temperature, and chlorine partial pressure in the reaction rate is analyzed for two MoO{sub 3} samples having different particle size and morphology. The experimental conditions for chemical control of the reaction rate were established for both types of samples. An average activation energy of 211 kJ mol{sup -1} and a reaction order of 1 with respect to chlorine partial pressure were determined for the chlorination of MoO{sub 3} with gaseous chlorine. A complete rate equation was formulated that describes the reaction evolution of each type of solid.

  10. 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....

  11. Can chlorination co-select antibiotic-resistance genes?

    Science.gov (United States)

    Lin, Wenfang; Zhang, Menglu; Zhang, Shenghua; Yu, Xin

    2016-08-01

    Selective pressures, such as chemical or heavy metal pollution, may co-select for bacterial antibiotic resistance in the environment. However, whether chlorination in water treatment can co-select antibiotic-resistant bacteria is controversial. In this study, high capacity quantitative polymerase chain reaction (qPCR) analysis was applied to target almost all known antibiotic-resistance genes (ARGs) (282 types) and 13 mobile genetic elements (MGEs) in bacteria detected in secondary effluents from a municipal wastewater treatment plant after chlorination. The results revealed that 125 unique ARGs were detected in non-chlorinated samples, and the number decreased (79-91 types) as the chlorine concentration was increased. Moreover, 7.49 × 10(4)-3.92 × 10(7) copies/100 ml water reduction of ARGs occurred with 4 mg Cl2/l. Considering the relative abundance of ARGs (i.e., ARG copies normalized to 16S rRNA gene copies), 119 ARGs decreased in response to chlorination, whereas only six ARGs, such as dfrA1, tetPB-03, tetPA, ampC-04, tetA-02, and erm(36), were potentially enriched by 10.90-, 10.06-, 8.63-, 6.86-, 3.77-, and 1.09-fold, respectively. Furthermore, the relative abundance of 12 detected MGEs was lower after chlorination. Therefore, chlorination was effective in reducing ARGs and MGEs rather than co-selecting them. PMID:27192478

  12. 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)

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

    International Nuclear Information System (INIS)

    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, 35Cl and 37Cl, 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, 36Cl 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)

  14. EFFECTS OF OZONE, CHLORINE DIOXIDE, CHLORINE, AND MONOCHLORAMINE ON CRYTOSPORIDIUM PARVUM OOCYST VIABILITY

    Science.gov (United States)

    Purified Cryptosporiodium parvum oocysts were exposed to ozone, chlorine dioxide, chlorine, and monochloramine. Excystation and mouse infectivity were compareatively evaluated to assess oocyst viability. Ozone and chlorine dioxide more effectively inactivated oocysts than chlor...

  15. Study of the angular correlations of light charged particles for the reaction {sup 35}CI (260 MeV) + {sup 24}Mg; Etude des correlations angulaires de particules legeres chargees dans la reaction {sup 35}CI (260 MeV) + {sup 24}Mg

    Energy Technology Data Exchange (ETDEWEB)

    Mahboub, D.

    1996-10-30

    This work is focussed on the investigation of deformed nuclei. The asymmetric fusion-fission of light heavy-ions (A {<=}60) with a high excitation energy (T {approx} 4 MeV) had lead to a large deformation of the compound nucleus at the scission point. The angular correlations between light particles (LP) and their emitting fragments has been used to probe the deformation of nucleus. Exclusive measurements were performed for the {sup 35}Cl (260 MeV) + {sup 24}Mg system leading to the {sup 59}Cu compound nucleus (CN). The comparison between the energy spectra of LP`s and a statistical calculation carried out by a Monte-Carlo code CASCADE has suggested a deformation of 1.3 (for an oblate shape) of the CN within the frame work of fusion-evaporation process. The source velocity spectrum of {alpha} particles and angular correlations of LP`s have showed that pre-scission and pre-equilibrium emissions are negligible in the present reaction. Finally the confrontation of the data with the statistical code GEMINI has pointed out the sequential emission character of the LP`s from the fission fragments. (author). 175 refs.

  16. Study of the transferred angular momentum as a function of the excitation energy in the Kr + U reaction at 35 A.MeV; Etude du moment angulaire transfere en fonction de l`energie d`excitation dans la reaction Kr + U a 35 A.MeV

    Energy Technology Data Exchange (ETDEWEB)

    Josset, M.

    1996-09-06

    The aim of this study is to measure the angular momentum transferred to the target-like product, in the Kr + U reaction at 35 A.MeV, as a function of the excitation energy. The measured neutron multiplicity, as seen by the detector ORION, was used as the basic event selection criterion. This multiplicity also allows an estimation of the excitation energy transferred to the target-like product on an event by event basis. The study of the behaviour of the projectile-like component allows one to characterize two-body mechanisms, which are associated with a large energy dissipation for less peripheral collisions. The spin transferred to the target-like component is deduced from the out-plane angular distributions of the fission fragments. The study of the angular correlation between these fission fragments confirms that the dominant mechanism is essentially a two-body process. We show that the angular momentum values obtained, as a function of the excitation energy of the target-like product, have little dependence on the time taken for the nucleus to reach the saddle point. We observe a constant increase in the target-like component`s spin, varying from 15{Dirac_h} to 60{Dirac_h}, as the excitation energy increases from roughly 8 to 400 MeV. For the higher excitation energies the spin does not increase. This behaviour reflects the vanishing binary fission mechanism at high angular momenta. (author). 81 refs.

  17. MECHANISM OF CHLORATE FORMATION IN CHLORINE DIOIXDE DELIGNIFICATION

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

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

    Science.gov (United States)

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

    2015-04-15

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

  19. Transformation of phenazone-type drugs during chlorination.

    Science.gov (United States)

    Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2012-05-01

    Chlorination is one of the most popular disinfection steps for water treatment in Europe. However, chlorine can react with pharmaceuticals and other micropollutants leading to either their elimination or by-products being formed. These by-products are frequently not identified and therefore the consequences of chlorination can be underestimated. In this work, the degradation of two analgesics and antipyretics, phenazone (antipyrine) and propyphenazone, during chlorination was investigated by liquid chromatography-mass spectrometry (LC-MS). A quadrupole-time-of-flight (Q-TOF) system was used to follow the time course of the pharmaceuticals, and also used in the identification of the by-products. The degradation kinetics was investigated at different concentrations of chlorine (1-10 mg/L), bromide (0-100 μg/L) and sample pH (5.7-8.3) by means of a Box-Behnken experimental design. Depending on these factors, half-lives were in the ranges: 0.9-295 s for phenazone and 0.4-173 s for propyphenazone. Also, it was observed that chlorine concentration was a significant factor for propyphenazone, resulting in increased degradation rate as it is increased. The transformation path of these drugs consisted mainly of halogenations, hydroxylations and dealkylations. After several days of reaction two derivatives remained stable for phenazone: chloro-hydroxy-phenazone and N-demethyl-chloro-hydroxy-phenazone and two for propyphenazone: N-demethyl-hydroxy-propyphenazone and N-demethyl-chloro-hydroxy-propyphenazone. Moreover, experiments conducted with real water matrices, tap and surface water, showed that reaction, and formation of by-products, can take place both at the emission source point (household) and during drinking water production. PMID:22381982

  20. Theoretical Study on the Reaction Mechanism and Kinetics of Fluorine and Chlorine Atoms with Ozone and Methane%F,Cl原子与臭氧和甲烷反应机理和反应动力学的理论研究

    Institute of Scientific and Technical Information of China (English)

    李来才; 徐伯华; 邓平

    2002-01-01

    Ab initio UMP2(full) method was performed to study the reaction mechanism of F and Cl atoms with methane and ozone.The geometry configurations of reactants,products,intermediates and transition states were optimized at UMP2(full)/6-31G* level and the energies of stationary points along the pathways were calculated at Gaussian-3(G3) and G3MP2 level.The results show that fluorine atoms react with ozone as violently as chlorine atoms;during the process of the reaction F+CH4,the hydrogen bond forms,the bond energy is 3.71 kJ/mol.In addition,fluorine atoms react readily with methane to form the intermediate with a hydrogen bond,which easily decomposed to form HF with stable properties.That is to say,the reaction F+CH4 is prior to the reaction F+O3 when there is a competition between methane and ozone.However,there is no hydrogen bond in the reaction Cl+CH4,and the reaction Cl+O3 is prior to Cl+CH4 when there is a competition between methane and ozone.Besides,we have calculated the rate constants of the fluorine and chlorine atoms with methane and ozone reactions.Therefore we can reasonably explain why chlorine atoms are the main reactants depleting ozone,while the more active fluorine atoms deplete less ozone.%用量子化学从头计算UMP2(full)方法研究F和Cl 原子与甲烷分子和臭氧之间的反应机理,优化了反应物、产物、中间体和过渡态的几何构型,在Gaussian-3(G3)和G3MP2水平计算了它们的能量.研究结果表明:F原子与Cl原子一样与臭氧之间有很强的反应活性,而F原子与甲烷分子反应过程中有氢键生成,键能为3.71 kJ/mol,F原子与甲烷分子之间反应活性比与臭氧分子之间反应活性强.F原子易与甲烷分子生成含有氢键的化合物,且很快分解生成化学性质非常稳定的HF,能同F+O3反应竞争.而Cl原子甲烷分子反应过程中则无氢键生成现象.且在Cl原子与臭氧和甲烷之间竞争反应时,Cl原子与臭氧之间反应优先,同时我们还对F

  1. Hot chlorine leaching techniques for determining failed-particle fraction in HTGR fuel compacts

    International Nuclear Information System (INIS)

    The high-temperature chlorine leaching techniques as nondestractive inspection of the failed-particle fraction in HTGR fuel compacts have been studied. Compacts containing bare UO2 kernels were leached with chlorine gas at temperatures from 7000 to 12000C by two methods. The static method using a closed quartz reaction vessel completely extracted the uranium, but it was difficult to purge the compact completely of chlorine. The flow method wherein chlorination was made in the gas stream within a glassy carbon tube had no problem of the residual chlorine. The static method simpler in operation is suitable for the post-irradiation experiment, and the flow method for the pre-irradiation inspection. (author)

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

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

    2016-08-01

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

  4. Control effects of pε and pH on the generation and stability of chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    PEI Yuan-sheng; WU Xiao-qiang; LUAN Zhao-kun; WANG Tong

    2003-01-01

    A new method, without assistance of activity ratio diagram, was applied to construct the pε-pH diagrams for chlorine system. The optimal pH range for generation of ClO2 by contacting Cl2(g) directly with ClO2- solution is within pH 1.35-1.94, particularly within pH 1.35-4.00 only if minimizing the formation of Cl2. It is unachievable to synthesize pure ClO2 from the reaction of Cl2 and ClO2-. Conversely, ClO2 may be present a variation of stability in different waters owing to the changed pε and pH. ClO2 could be relatively stable if not disproportionate into ClO3-, coexisting with ClO2- (pε17.63 and pH>9.68), Cl2 (pH≤0.92) or Cl- (pH 0.92-9.68). When chlorine system has already reached the ultimate equilibria, ClO2 is a stable species in strongly acid media. As the acidity decreases, ClO2 disproportionates into ClO3- and Cl2. Aqueous ClO2 is unstable within the normal pH range. This work initially, theoretically elucidates the generation and stability of ClO2 by way of the pε-pH diagrams.

  5. Chlorine/UV Process for Decomposition and Detoxification of Microcystin-LR.

    Science.gov (United States)

    Zhang, Xinran; Li, Jing; Yang, Jer-Yen; Wood, Karl V; Rothwell, Arlene P; Li, Weiguang; Blatchley Iii, Ernest R

    2016-07-19

    Microcystin-LR (MC-LR) is a potent hepatotoxin that is often associated with blooms of cyanobacteria. Experiments were conducted to evaluate the efficiency of the chlorine/UV process for MC-LR decomposition and detoxification. Chlorinated MC-LR was observed to be more photoactive than MC-LR. LC/MS analyses confirmed that the arginine moiety represented an important reaction site within the MC-LR molecule for conditions of chlorination below the chlorine demand of the molecule. Prechlorination activated MC-LR toward UV254 exposure by increasing the product of the molar absorption coefficient and the quantum yield of chloro-MC-LR, relative to the unchlorinated molecule. This mechanism of decay is fundamentally different than the conventional view of chlorine/UV as an advanced oxidation process. A toxicity assay based on human liver cells indicated MC-LR degradation byproducts in the chlorine/UV process possessed less cytotoxicity than those that resulted from chlorination or UV254 irradiation applied separately. MC-LR decomposition and detoxification in this combined process were more effective at pH 8.5 than at pH 7.5 or 6.5. These results suggest that the chlorine/UV process could represent an effective strategy for control of microcystins and their associated toxicity in drinking water supplies. PMID:27338715

  6. The production of K0 in p+p reactions at 3.5 GeV. Inclusive and exclusive studies with the HADES detector

    International Nuclear Information System (INIS)

    The present work deals with an inclusive and an exclusive K0 analysis of the p+p data - recorded with the HADES experiment at 3.5 GeV - for the determination of the K0 production dynamic, of production cross sections and angular distributions in particular in the context of resonances (e.g. Δ(1232)++). The exclusive results, which show the presence of a dominant resonance contribution, were, thereby, implemented in theoretical models allowing the reproduction of the inclusive K0 kinematics.

  7. Analysis of the reaction π+-nucleon→π+π+π-π0π0-nucleon at 3.5GeV/c

    International Nuclear Information System (INIS)

    Complete π0's reconstruction in heavy liquid bubble chamber has allowed to study the π+π+π-π0π0-nucleon channel produced by π+ of 3.5GeV/c. Individual particle properties as well as various angular and mass correlations have been studied. The main results are: importante ω0 production, π0π0 strong correlation, fit of CLA-type phenomenological model (Chang Hong Mo-Loskiewicz-Allison model) which accounts well for the experimental data. The two (correlated) neutral pions are preferentially produced at the lower vertices

  8. Environmental Behavior, Sources, and Effects of Chlorinated Polycyclic Aromatic Hydrocarbons

    Directory of Open Access Journals (Sweden)

    Takeshi Ohura

    2007-01-01

    Full Text Available The environmental sources and behaviors of chlorinated 2- to 5-ring polycyclic aromatic hydrocarbons (ClPAHs. ClPAHs are ubiquitous contaminants found in urban air, vehicle exhaust gas, snow, tap water, and sediments. The concentrations of ClPAHs in each of these environments are generally higher than those of dioxins but markedly lower than the concentrations of the parent compounds, PAHs. Environmental data and emission sources analysis for ClPAHs reveal that the dominant process of generation is by reaction of PAHs with chlorine in pyrosynthesis. This secondary reaction process also occurs in aquatic environments. Certain ClPAHs show greater toxicity, such as mutagenicity and aryl hydrocarbon receptor activity, than their corresponding parent PAHs. Investigation of the sources and environmental behavior of ClPAHs is of great importance in the assessment of human health risks.

  9. Identification of Some AOX Compounds Formed in Wool Chlorination Using Model Chemicals

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; HE Jin-xin; DAJ Jin-jin

    2002-01-01

    The AOX (adsorbable organic halogens) problem in wool shrinkproofing effluents has attracted more attention in recent years. The probable origins and structures of AOX compounds were proved by the reaction of DCCA with the model substances of different amino acid residues.The GC-MS results indicated that available chlorine could chlorinate the side chain of tyrosine, histidine and trypotophan and generate AOX load in the effluent.

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

    OpenAIRE

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

    1990-01-01

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

  11. Kinetics of the gas-phase reactions of chlorine atoms with CH2F2, CH3CCl3 and CF3CFH2 over the temperature range 253 – 551 K

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Johnson, Matthew Stanley; Nielsen, Ole John;

    2009-01-01

    Relative rate techniques were used to study the title reactions in 930–1200 mbar of N2 diluent. The reaction rate coefficients measured in the present work are summarized by the expressions k(Cl+CH2F2) = 1.19×10-17 T 2 exp(-1023/T ) cm3 molecule-1 s-1 (253– 553 K), k(Cl+CH3CCl3) = 2.41×10-12 exp(...

  12. Corrosion of copper by chlorine trifluoride

    International Nuclear Information System (INIS)

    The research described called for a considerable amount of preliminary development of the test methods and equipment in order that the various measurements and observations could be carried out without contaminating either the samples or this highly reactive gas. The chlorine trifluoride was highly purified before use, its purity being checked by gas-phase chromatography, micro-sublimation and infrared spectrography. The tests were carried out on copper samples of various purities, in particular a 99.999 per cent copper in the form of mono-crystals. They involved kinetic measurements and the characterization of corrosion products under different temperature and pressure conditions. The kinetics showed reactions of the same order of magnitude as those obtained with elementary fluorine. At atmospheric pressure there occurs formation of cupric fluoride and cuprous chloride. The presence of this latter product shows that it is not possible to consider ClF3 simply as a fluorinating agent. At low pressures an unknown product has been characterized. There are strong grounds for believing that it is the unstable cuprous fluoride which it has not yet been possible to isolate. A germination phenomenon has been shown to exist indicating an analogy between the initial phases of fluorination and those of oxidation. Important effects resulting from the dissociation of the copper fluorides and the solubility of chlorine in this metal have been demonstrated. Finally, tests have shown the considerable influence of the purity of the gas phase and of the nature of the reaction vessel walls on the rates of corrosion which can in certain cases be increased by a factor of several powers of ten. (author)

  13. The influence of chlorine on the gasification of wood

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-06-01

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

  14. Study of two- and multi-particle correlations in 12C+24Mg and 12C+208Pb reactions at E=35 AMeV

    Directory of Open Access Journals (Sweden)

    Quattrocchi L.

    2016-01-01

    Full Text Available Two and multi particle correlations from the decay of sources produced in 12C+24Mg and 12C+208Pb collisions at E=35 AMeV have been studied by using the forward part (1° < θlab < 30° of the CHIMERA multi-detector. Correlations and invariant mass spectroscopy are used to explore simultaneous and sequential decays of resonances in light isotopes with Z∼3-6, produced in peripheral collisions via the break-up of excited quasi-projectiles. Among them we mention 5Li, 6Li, 6Be, 8Be and the astrophysically important state in 12C decaying into three alpha particles. Results and future perspectives at the INFN-LNS will be presented.

  15. Study of multipion systems produced in the reaction π+N→Nπ+π+π-π0π0 at 3.5GeV/c

    International Nuclear Information System (INIS)

    A detailed analysis is presented of events belonging to the final state N2π+π-2π0 produced in π+ nuclei interactions at 3,5 GeV/c in a heavy liquid bubble chamber. Individual particle momentum distributions as well as center of mass angular emission distributions display deviations from the statistical phase space. A strong angular correlation is found in particular between the two π0 which can not be explained by the symmetrization of the wave functions and which produces an enhancement at low π0π0 masses. The ω0 production is found in 39+-7% of the events and the cross section on hydrogen is estimated at 1.1+-0.3 mb

  16. Enhanced Elemental Mercury Removal from Coal-fired Flue Gas by Sulfur-chlorine Compounds

    OpenAIRE

    Miller, Nai-Qiang Yan-Zan Qu Yao Chi Shao-Hua Qiao Ray Dod Shih-Ger Chang Charles

    2008-01-01

    Oxidation of Hg0 with any oxidant or converting it to a particle-bound form can facilitate its removal. Two sulfur-chlorine compounds, sulfur dichloride (SCl2) and sulfur monochloride (S2Cl2), were investigated as oxidants for Hg0 by gas phase reaction and by surface-involved reactions in the presence of flyash or activated carbon. The gas phase reaction rate constants between Hg0 and the sulfur/chlorine compounds were determined, and the effects of temperature and the main components in flue...

  17. Réaction du polyisobutène chloré sur l'anhydride maléique : mécanisme. Catalyse par l'anhydride dichloromaléique Reaction of Chlorinated Polyisobutene on Maleic Anhydride. Mechanism. Catalysis by Dichloromaleic Anhydride

    Directory of Open Access Journals (Sweden)

    Sillion B.

    2006-11-01

    Full Text Available Dans cet article le mécanisme de la réaction de condensation du polyisobutène chloré sur l'anhydride maléique, qui sert dans la synthèse d'additif pour lubrifiant, est étudié par une cinétique globale et par un travail sur composés modèles. Il est montré que, dans cette réaction, l'anhydride maléique joue un double rôle : de catalyseur de déshydrochloration par une réactivité de type acide de Lewis organique, de réactif comme diénophile. Grâce à ces résultats, il est proposé une catalyse par l'anhydride dichloromaléique, qui permet une amélioration sensible du procédé. This article examines the mechanism of the chlorinated-polyisobutene condensation reaction on maleic anhydride. The overall kinetics and model compounds are investigated for this reaction which is used in the synthesis of lubricant additives. Maleic anhydride is shown to play the dual role of a dehydrochlorination catalyst by having a reactivity of the organic Lewis acid type and of a reactant like dienophile. These results are used to propose a catalysis by dichloromaleic anhydride which appreciably improves the process.

  18. Formation and chlorination of polychlorinated naphthalenes (PCNs) in the post-combustion zone during MSW combustion.

    Science.gov (United States)

    Jansson, Stina; Fick, Jerker; Marklund, Stellan

    2008-07-01

    Non- to octa-chlorinated naphthalenes (PCNs) were analyzed in flue gas samples collected simultaneously at three different temperatures (450 degrees C, 300 degrees C and 200 degrees C, respectively) in the post-combustion zone during waste combustion experiments using a laboratory-scale fluidized-bed reactor. PCN homologue profiles in all samples were dominated by the lower chlorinated homologues (mono- to triCN), with successive reductions in abundance with each additional degree of chlorination. The isomer distribution patterns reflected ortho-directionality behavior of the first chlorine substituent, and the beta-positions, i.e. the 2,3,6,7-substitution sites, seemed to be favored for chlorination. Injection of naphthalene into the post-combustion zone resulted in increased PCN levels at 200 degrees C, demonstrating the occurrence of chlorination reactions in the post-combustion zone. However, the increases were restricted to the least-chlorinated homologue (monoCN), probably because there was insufficient residence time for further chlorination. In addition, an episode of poor combustion (manifested by high CO levels) was accompanied by extensive formation of 1,8-diCN, 1,2,3- and 1,2,8-triCN; congeners with substitution patterns that are not thermodynamically favorable. These are believed to be products of PAH breakdown reactions and/or chlorophenol condensation. Overall, PCN formation is likely to occur via more than one pathway, including chlorination of naphthalene that is already present, de novo synthesis from PAHs and, possibly, chlorophenol condensation.

  19. Precise determination of stable chlorine isotopic ratios in low-concentration natural samples

    Science.gov (United States)

    Magenheim, A. J.; Spivack, A. J.; Volpe, C.; Ransom, B.

    1994-07-01

    Investigation of stable chlorine isotopes in geological materials has been hindered by large sample requirements and/or lack of analytical precision. Here we describe precise methods for the extraction, isolation, and isotopic analysis of low levels of chlorine in both silicate and aerosol samples. Our standard procedure uses 2 μg of Cl for each isotopic analysis. External reproducibility (1 σ) is 0.25%. for the 37Cl /35Cl measurements. Chlorine is extracted from silicate samples (typically containing at least 20 μg of Cl) via pyrohydrolysis using induction heating and water vapor as the carrier, and the volatilized chlorine is condensed in aqueous solution. Atmospheric aerosols collected on filters are simply dissolved in water. Prior to isotopic measurement, removal of high levels of SO 42-, F -, and organic compounds is necessary for the production of stable ion beams. Sulfate is removed by BaSCO 4 precipitation, F - by CaF 2 precipitation, and organic compounds are extracted with activated carbon. Chlorine is converted to stoichiometric CsCl by cation exchange, and isotopic ratios are determined by thermal ionization mass spectrometry of Cs 2Cl +. We demonstrate that the sensitivity and precision of this method allow resolution of natural variations in chlorine isotopic composition, and thereby provide insight to some fundamental aspects of chlorine geochemistry.

  20. Aluminum recovery from coal fly ash by high temperature chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Wijatno, H.

    1977-10-01

    A study of aluminum recovery from power plant fly ash by high temperature chlorination was undertaken to demonstrate that fly ash could be a potential source of aluminum, iron and possibly silicon. Magnetic separation of the iron oxide served as a first step to alleviate the iron contamination problem. However, the agglomeration of some iron oxide with alumina and silica made it difficult to completely separate the iron from the fly ash. Further iron separation was achieved by chlorinating the nonmagnetic ash fraction at 550/sup 0/C for 30 minutes. This reduced the iron oxide content to less than 4 percent by weight. Chlorine flow rates affected the reaction rate much more drastically than temperatures. This suggested that diffusion was the major rate-controlling step. Besides Fe/sub 2/O/sub 3/, Al/sub 2/O/sub 3/ and SiO/sub 2/, other oxides such as CaO, K/sub 2/O, Na/sub 2/O and MgO might have complicated the alumina recovery by forming individual chlorides or complexes. Investigating methods for separating more Fe/sub 2/O/sub 3/, and possibly CaO, K/sub 2/O, Na/sub 2/O and MgO from the nonmagnetic ash fraction before chlorinating it is highly recommended.

  1. A marine sink for chlorine in natural organic matter

    Science.gov (United States)

    Leri, Alessandra C.; Mayer, Lawrence M.; Thornton, Kathleen R.; Northrup, Paul A.; Dunigan, Marisa R.; Ness, Katherine J.; Gellis, Austin B.

    2015-08-01

    Chloride--the most abundant ion in sea water--affects ocean salinity, and thereby seawater density and ocean circulation. Its lack of reactivity gives it an extremely long residence time. Other halogens are known to be incorporated into marine organic matter. However, evidence of similar transformations of seawater chloride is lacking, aside from emissions of volatile organochlorine by marine algae. Here we report high organochlorine concentrations from 180 to 700 mg kg-1 in natural particulate organic matter that settled into sediment traps at depths between 800 and 3,200 m in the Arabian Sea, taken between 1994 and 1995. X-ray spectromicroscopic imaging of chlorine bonding reveals that this organochlorine exists primarily in concentrated aliphatic forms consistent with lipid chlorination, along with a more diffuse aromatic fraction. High aliphatic organochlorine in particulate material from cultured phytoplankton suggests that primary production is a source of chlorinated organic matter. We also found that particulate algal detritus can act as an organic substrate for abiotic reactions involving Fe2+, H2O2 or light that incorporate chlorine into organic matter at levels up to several grams per kilogram. We conclude that transformations of marine chloride to non-volatile organochlorine through biological and abiotic pathways represent an oceanic sink for this relatively unreactive element.

  2. Correlations between emission timescale of fragments and isospin dynamics in $^{124}$Sn+$^{64}$Ni and $^{112}$Sn+$^{58}$Ni reactions at 35 AMeV

    CERN Document Server

    De Filippo, E; Russotto, P; Amorini, F; Anzalone, A; Auditore, L; Baran, V; Berceanu, I; Borderie, B; Bougault, R; Bruno, M; Cap, T; Cardella, G; Cavallaro, S; Chatterjee, M B; Chbihi, A; Colonna, M; D'Agostino, M; Dayras, R; Di Toro, M; Frankland, J; Galichet, E; Gawlikowicz, W; Geraci, E; Grzeszczuk, A; Guazzoni, P; Kowalski, S; La Guidara, E; Lanzalone, G; Lanzanò, G; Neindre, N Le; Lombardo, I; Maiolino, C; Papa, M; Piasecki, E; Pirrone, S; Planeta, R; Politi, G; Pop, A; Porto, F; Rivet, M F; Rizzo, F; Rosato, E; Schmidt, K; Siwek-Wilczynska, K; Skwira-Chalot, I; Trifirò, A; Trimarchi, M; Verde, G; Vigilante, M; Wieleczko, J P; Wilczynski, J; Zetta, L; Zipper, W

    2012-01-01

    We present a new experimental method to correlate the isotopic composition of intermediate mass fragments (IMF) emitted at mid-rapidity in semi-peripheral collisions with the emission timescale: IMFs emitted in the early stage of the reaction show larger values of $$ isospin asymmetry, stronger angular anisotropies and reduced odd-even staggering effects in neutron to proton ratio $$ distributions than those produced in sequential statistical emission. All these effects support the concept of isospin "migration", that is sensitive to the density gradient between participant and quasi-spectator nuclear matter, in the so called neck fragmentation mechanism. By comparing the data to a Stochastic Mean Field (SMF) simulation we show that this method gives valuable constraints on the symmetry energy term of nuclear equation of state at subsaturation densities. An indication emerges for a linear density dependence of the symmetry energy.

  3. Chloro({2-[mesityl(quinolin-8-yl-κNboryl]-3,5-dimethyl-phenyl}methyl-κCpalladium(II as a Catalyst for Heck Reactions

    Directory of Open Access Journals (Sweden)

    Sem Raj Tamang

    2015-07-01

    Full Text Available We recently reported an air and moisture stable 16-electron borapalladacycle formed upon combination of 8-quinolyldimesitylborane with bis(benzonitriledichloropalladium(II. The complex features a tucked mesityl group formed upon metalation of an ortho-methyl group on a mesityl; however it is unusually stable due to contribution of the boron pz orbital in delocalizing the carbanion that gives rise to an η4-boratabutadiene fragment coordinated to Pd(II, as evidenced from crystallographic data. This complex was observed to be a highly active catalyst for the Heck reaction. Data of the catalyst activity are presented alongside data found in the literature, and initial comparison reveals that the borapalladacycle is quite active. The observed catalysis suggests the borapalladacycle readily undergoes reductive elimination; however the Pd(0 complex has not yet been isolated. Nevertheless, the ambiphilic ligand 8-quinolyldimesitylborane may be able to support palladium in different redox states.

  4. Chloro({2-[mesityl(quinolin-8-yl-κN)boryl]-3,5-dimethyl-phenyl}methyl-κC)palladium(II) as a catalyst for Heck reactions.

    Science.gov (United States)

    Tamang, Sem Raj; Hoefelmeyer, James D

    2015-01-01

    We recently reported an air and moisture stable 16-electron borapalladacycle formed upon combination of 8-quinolyldimesitylborane with bis(benzonitrile)dichloropalladium(II). The complex features a tucked mesityl group formed upon metalation of an ortho-methyl group on a mesityl; however it is unusually stable due to contribution of the boron pz orbital in delocalizing the carbanion that gives rise to an η4-boratabutadiene fragment coordinated to Pd(II), as evidenced from crystallographic data. This complex was observed to be a highly active catalyst for the Heck reaction. Data of the catalyst activity are presented alongside data found in the literature, and initial comparison reveals that the borapalladacycle is quite active. The observed catalysis suggests the borapalladacycle readily undergoes reductive elimination; however the Pd(0) complex has not yet been isolated. Nevertheless, the ambiphilic ligand 8-quinolyldimesitylborane may be able to support palladium in different redox states. PMID:26193250

  5. 二氧化氯/TiO2光催化氧化降解碱性品红模拟废水及反应机理%Investigation of Chlorine Dioxide/TiO2 Photocatalytic Oxidative Degradation of Simulated Wastewater Containing Fuchsine and Its Reaction Mechanism

    Institute of Scientific and Technical Information of China (English)

    施来顺; 王晓美

    2012-01-01

    The photocatalyst TiO2 was prepared by dipping-calcination method using silica gel as catalyst support.The chlorine dioxide/TiO2 photocatalyst was used for the photocatalytic oxidation of simulated fuchsine wastewater.The degradation effect of fuchsine by the combination of chlorine dioxide,TiO2 photocatalyst and UV irradiation was confirmed by comparison test.The optimum treatment conditions were as follows:the volume of wastewater containing 150 mg·L-1 fuchsine was 50 mL;ClO2 concentration was 6.14 mg·L-1,pH value was 5.0;the distance between UV lamp and flask was 20 cm;UV irradiation time was 13 min;and photocatalyst dosage was 10 g·L-1.The removal efficiency of fuchsine could reach 80%,compared with 46% of chlorine dioxide chemical oxidation.With UV-vis and FT IR analysis technique,the intermediates in the degradation process were obtained.Fuchsine was degradated into quinone and carboxylic acid,and finally changed into carbon dioxide and water during the photocatalytic oxidation.The degradation reaction mechanism of fuchsine by chlorine dioxide/TiO2 photocatalytic oxidation was proposed.%以硅胶为载体,采用浸渍-焙烧法制备了TiO2光催化剂,并将其用于二氧化氯/TiO2光催化氧化降解碱性品红模拟废水.经对比实验验证了ClO2/TiO2光催化剂/UV照射对碱性品红的氧化降解作用.50 mL质量浓度为150 mg.L-1的碱性品红模拟废水,在pH值为5.0,二氧化氯质量浓度6.14 mg.L-1和10 g.L-1光催化剂条件下,紫外照射距离20 cm,紫外照射时间13 min,碱性品红的去除率可达80%,远远高于二氧化氯化学氧化处理碱性品红的去除率46%.在废水处理过程中,采用紫外可见光谱和红外光谱分析降解产物,碱性品红被氧化降解为醌和羧酸,并进一步降解为二氧化碳和水,提出了二氧化氯/TiO2光催化氧化降解碱性品红废水的反应机理.

  6. Kinetics of aqueous chlorination of some pharmaceuticals and their elimination from water matrices.

    Science.gov (United States)

    Acero, Juan L; Benitez, F Javier; Real, Francisco J; Roldan, Gloria

    2010-07-01

    Apparent rate constants for the reactions of four selected pharmaceutical compounds (metoprolol, naproxen, amoxicillin, and phenacetin) with chlorine in ultra-pure (UP) water were determined as a function of the pH. It was found that amoxicillin (in the whole pH range 3-12), and naproxen (in the low pH range 2-4) presented high reaction rates, while naproxen (in the pH range 5-9), and phenacetin and metoprolol (in the pH range 2.5-12 for phenacetin, and 3-10 for metoprolol) followed intermediate and slow reaction rates. A mechanism is proposed for the chlorination reaction, which allowed the evaluation of the intrinsic rate constants for the elementary reactions of the ionized and un-ionized species of each selected pharmaceutical with chlorine. An excellent agreement is obtained between experimental and calculated rate constants by this mechanism.The elimination of these substances in several waters (a groundwater, a surface water from a public reservoir, and two effluents from municipal wastewater treatment plants) was also investigated at neutral pH. The efficiency of the chlorination process with respect to the pharmaceuticals elimination and the formation THMs was also established. It is generally observed that the increasing presence of organic and inorganic matter in the water matrices demand more oxidant agent (chlorine), and therefore, less chlorine is available for the oxidation of these compounds. Finally, half-life times and oxidant exposures (CT) required for the removal of 99% of the four pharmaceuticals are also evaluated. These parameters are useful for the establishment of safety chlorine doses in oxidation or disinfection stages of pharmaceuticals in treatment plants.

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

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

  8. Flash photolysis of chlorine dioxide in aqueous solution

    International Nuclear Information System (INIS)

    The primary process when aqueous solutions of chlorine dioxide are flash photo-lysed by light with a wave length greater than 270 nm is: OClO →hν ClO (2Π) + O (3P). The photochemical decomposition is characterized by the formation of small quantities of O (3P) atoms and of equal amounts of chlorine atoms and molecular oxygen, the latter originating in the reaction: ClOO → Cl + O2. The isomer ClOO is formed by the germinate recombination of ClO and O, a process which is twice as important as diffusion of the fragments into the mass of the solution and one which represents 30 per cent of the decomposition of the chlorine dioxide. Under our experimental conditions, the lifetime of the ClOO is less than one microsecond. Chlorine atoms are precursors of Cl2O2, whose UV absorption spectrum has been determined, and which is formed by the reactions: Cl + OClO → Cl2O2; Cl + Cl- → Cl2-; Cl2- + OClO → Cl2O2 + Cl- k = (1,0 ±0,1) 109 M-1s-1. Cl2O2 disappears by a first-order process which leads to the formation of the ions Cl- and ClO3-. Competition between the reactions: O (3P) + O2 → O3; O (3P) + OClO → ClO3. (kOClO + O)/(kO2 + O) = 1.85±0.25 has been studied and the molar extinction coefficient of ClO3 determined at its absorption maximum (255 nm): ε255nm = (920 ± 90) M-1 cm-1. (author)

  9. Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes.

    Science.gov (United States)

    Li, Tong; Jiang, Yan; An, Xiaoqiang; Liu, Huijuan; Hu, Chun; Qu, Jiuhui

    2016-10-01

    The synergistic effect of ultraviolet light (UV) and chlorine on the structural transformation of Humic Acid (HA) and formation of chloro-disinfection byproducts (DBPs) in water were investigated, with chlorination as a reference. The transformation and mineralization of HA were enhanced upon co-exposure to UV and chlorine. Electron spin resonance (ESR) studies revealed that hydroxyl radical (OH) and chlorine radical (Cl) were predominant active species in a pH range from 4 to 7, while Cl dominated at pH 2 and pH higher than 7. The impact of different radicals on the transformation of HA was investigated by UV254, fluorescence and TOC measurements. OH were found to be responsible for the removal of chromophoric groups and mineralization of HA, while Cl mainly reacted with HA and intermediates from HA degradation. Due to the competitive and synergistic reaction of OH and Cl with HA, higher removal of HA and lower formation of chloro-DBPs appeared in UV-chlorine than chlorination, thus the combined UV-chlorine processes should be a promising method for water purification.

  10. Formation of new brominated disinfection byproducts during chlorination of saline sewage effluents.

    Science.gov (United States)

    Ding, Guoyu; Zhang, Xiangru; Yang, Mengting; Pan, Yang

    2013-05-15

    Chlorination could be the most cost-effective method for disinfecting saline sewage effluents resulting from toilet flushing with seawater. Upon chlorination, the high levels of bromide ions in saline sewage effluents (up to 32 mg/L) can be oxidized to hypobromous acid/hypobromite, which could then react with organic matter in the sewage effluents to form brominated disinfection byproducts (Br-DBPs). In this study, primary and secondary saline sewage effluents were collected and chlorinated at different chlorine doses, and a powerful precursor ion scan method using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry was adopted for detection and identification of polar Br-DBPs in these samples. With the new method, 54 major polar Br-DBPs were detected in the chlorinated saline effluents and six of them were newly identified as wastewater DBPs, including bromomaleic acid, 5-bromosalicylic acid, 3,5-dibromo-4-hydroxybenzaldehyde, 3,5-dibromo-4-hydroxybenzoic acid, 2,6-dibromo-4-nitrophenol, and 2,4,6-tribromophenol. The formation of polar Br-DBPs, especially those newly detected ones, during chlorination of the saline effluents was studied. For the secondary saline effluent, various polar Br-DBPs formed and reached their maximum levels at different chlorine doses, whereas for the primary saline effluent, the formation of polar Br-DBPs basically kept increasing with increasing chlorine dose. Compared with the secondary saline effluent, the primary saline effluent generated fewer and less Br-DBPs and rarely generated nitrogenous Br-DBPs.

  11. Contribution of liquid, NAT and ice particles to chlorine activation and ozone depletion during Antarctic winter and spring

    Directory of Open Access Journals (Sweden)

    O. Kirner

    2014-06-01

    Full Text Available Heterogeneous reactions in the Antarctic stratosphere are the cause of chlorine activation and ozone depletion, but the relative roles of different types of PSCs in chlorine activation is an open question. We use multi-year simulations of the chemistry-climate model EMAC to investigate the impact that the various types of PSCs have on Antarctic chlorine activation and ozone loss. One standard and three sensitivity EMAC simulations have been performed. The results of these simulations show that the significance of heterogeneous reactions on NAT and ice particles, in comparison to liquid particles, is subordinate regarding chlorine activation and ozone depletion in Antarctic winter and spring. The heterogeneous chemistry on liquid particles is sufficient to activate at least 90% of the chlorine reservoir species. With the exception of the upper PSC regions between 10 and 30 hPa where temporarily the ice particles have a relevant contribution to the chlorine activation and during the initial PSC occurrence with short NAT contributions the liquid particles alone are sufficient to activate almost all of the available chlorine. In the model simulations heterogeneous chemistry on liquid particles is responsible for more than 90% of the ozone depletion in Antarctic spring. Only up to 5 DU of column ozone in high southern latitudes is depleted by chlorine activation due to additional heterogeneous chemistry on ice particles and less than 0.5 DU due to additional heterogeneous chemistry on NAT particles.

  12. Ultrafast measurements of chlorine dioxide photochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ludowise, P.D.

    1997-08-01

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

  13. [Degradation Kinetics and Formation of Disinfection By-products During Linuron Chlorination in Drinking Water].

    Science.gov (United States)

    Ling, Xiao; Hu, Chen-yan; Cheng, Ming; Gu, Jian

    2015-05-01

    Chlorination degradation of linuron was studied using the common disinfectant sodium hypochlorite, the effects of chlorine dosage, pH value, bromine ion concentrationand temperature were systematically investigated, and the formation characteristics of disinfection by-products (DBPs) during the chlorination reaction was analyzed. The results showed that the chlorination degradation kinetics of linuron by sodium hypochlorite could be well described by the second-order kinetic model. Moreover, pH values had a great impact on the degradation reaction, and the rate constant reached the maximum level at pH 7, and the base elementary reaction rate constants of HOCl and OCl- with linuron were 4.84 x 10(2) L · (mol · h)(-1) and 3.80 x 10(2) L · (mol · h)(-1), respectively. The reaction rate decreased with the addition of bromide ion and increased with increasing temperature. Furthermore, many kinds of disinfection by- products were produced during the chlorination degradation of linuron, including CF, DCAN, TCNM and halogen acetone. Under conditions of different solution pH and different bromide ion concentrations, there would be significant difference in the types and concentrations of disinfection by-products.

  14. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments.

    Science.gov (United States)

    Li, Jian; Ma, Li-yun; Xu, Li

    2016-07-01

    The present study focused on the kinetics, transformation pathways and toxicity of several benzophenone-type ultraviolet filters (BPs) during the water chlorination disinfection process. The transformation kinetics of the studied three BPs was found to be second-order reaction, which was dependent on the concentration of BPs and chlorine. The second-order rate constants increased from 86.7 to 975 M(-1) s(-1) for oxybenzone, 49.6-261.7 M(-1) s(-1) for 4-hydroxybenzophenone and 51.7-540 M(-1) s(-1) for 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid with the increasing pH value from 6 to 8 of the chlorination disinfection condition. Then the transformation products (TPs) of these BPs were identified by HPLC-QTof analysis. Several transformation pathways, including electrophilic substitution, methoxyl substitution, ketone groups oxidation, hydrolysis, decarboxylation and ring cleavage reaction, were speculated to participate in the chlorination transformation process. Finally, according to the toxicity experiment on luminescent bacteria, Photobacterium phosphoreum, enhanced toxicity was observed for almost all the TPs of the studied BPs except for 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; it suggested the formation of TPs with more toxic than the parent compounds during the chlorination process. The present study provided a foundation to understand the transformation of BPs during chlorination disinfection process, and was of great significance to the drinking water safety.

  15. The enhanced electrocatalytic activity of graphene co-doped with chlorine and fluorine atoms

    International Nuclear Information System (INIS)

    Graphene co-doped with fluorine and chlorine was prepared through a one-step synthesis to greatly enhance its electrocatalytic activity and stability for oxygen reduction reaction. - Highlights: • Developed a one-step synthesis of graphene co-doped with different halogen atoms. • The obtained graphene exhibits great electrocatalytic activity in the oxygen reduction reaction. • The chlorine–fluorine co-doped graphene has great stability in methanol crossover effect. • Experiments indicate that there are possible synergetic interactions between halogen dopants. - Abstract: Graphene co-doped with fluorine and chlorine heteroatoms was prepared through a one-step synthesis and was investigated as the oxygen reduction electrocatalysts. Voltammetric measurements show that fluorine and chlorine co-doped graphene has remarkable catalytic activity toward the electrochemical reduction of oxygen in alkaline solution. Besides having a high tolerance to methanol crossover effect, the co-doped graphene also showed a better stability than that of commercial Pt/C electrocatalysts and of the chlorine-doped graphene that was prepared by the same approach. The charge transfer resistance of the co-doped graphene was substantially lower than that of the chlorine-doped graphene, suggesting that there may exist a synergistic interaction between fluorine and chlorine dopants. The rapid synthetic method reported here provides an effective approach for future investigation of halogen (co-) doped graphene

  16. Chlorination of oxybenzone: Kinetics, transformation, disinfection byproducts formation, and genotoxicity changes.

    Science.gov (United States)

    Zhang, Shujuan; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F

    2016-07-01

    UV filters are a kind of emerging contaminant, and their transformation behavior in water treatment processes has aroused great concern. In particular, toxic products might be produced during reaction with disinfectants during the disinfection process. As one of the most widely used UV filters, oxybenzone has received significant attention, because its transformation and toxicity changes during chlorine oxidation are a concern. In our study, the reaction between oxybenzone and chlorine followed pseudo-first-order and second-order kinetics. Three transformation products were detected by LC-MS/MS, and the stability of products followed the order of tri-chloro-methoxyphenoyl > di-chlorinated oxybenzone > mono-chlorinated oxybenzone. Disinfection byproducts (DBPs) including chloroform, trichloroacetic acid, dichloroacetic acid and chloral hydrate were quickly formed, and increased at a slower rate until their concentrations remained constant. The maximum DBP/oxybenzone molar yields for the four compounds were 12.02%, 6.28%, 0.90% and 0.23%, respectively. SOS/umu genotoxicity test indicated that genotoxicity was highly elevated after chlorination, and genotoxicity showed a significantly positive correlation with the response of tri-chloro-methoxyphenoyl. Our results indicated that more genotoxic transformation products were produced in spite of the elimination of oxybenzone, posing potential threats to drinking water safety. This study shed light on the formation of DBPs and toxicity changes during the chlorination process of oxybenzone.

  17. Kinetic preference for the 3'-5'-linked dimer in the reaction of guanosine 5'-phosphorylmorpholinamide with deoxyguanosine 5'-phosphoryl-2-methylimidazolide as a function of poly(C) concentration

    Science.gov (United States)

    Kanavarioti, A.

    1998-01-01

    The formation of the internucleotide bond in diguanylate synthesis was studied in aqueous solution at pH 8 and 0.2 M Mg2+ in the presence and absence of polycytidylate, poly(C). The investigation was simplified by using guanosine 5'-phosphorylmorpholinamide, mor-pG, which can act only as a nucleophile, and deoxyguanosine 5'-phosphoryl-2-methylimidazolide, 2-MeImpdG, which can act only as an electrophile. The time-dependent product distribution was monitored by high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS). In the absence of poly(C) the reaction between mor-pG and 2-MeImpdG yielded small amounts of the dimer mor-pGpdG with a regioselectivity of 2'-5':3'-5' = 3.5. In the presence of poly(C) dimer yields increased and a reversal in regioselectivity occurred; both effects were in proportion to the concentration of the polymer. The results can be quantitatively explained with the proposition that poly(C), acting as the template, catalyzes the reaction between template-bound monomers by about a factor of 4-5 over the reaction in solution and yields dimers with a regioselectivity of 2'-5':3'-5' approximately 0.33. These findings illustrate the intrinsic preference of guanosine monomers to correctly self-assemble on the appropriate template.

  18. 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.

  19. Degradation of atrazine by UV/chlorine: Efficiency, influencing factors, and products.

    Science.gov (United States)

    Kong, Xiujuan; Jiang, Jin; Ma, Jun; Yang, Yi; Liu, Weili; Liu, Yulei

    2016-03-01

    In this work, the degradation of atrazine by the combination of UV and chlorine (UV/chlorine) due to the formation of radicals during chlorine photolysis was systematically investigated in terms of efficiency, factors that influence the degradation kinetics, as well as oxidation products. It was found that the degradation efficiency of atrazine was enhanced by UV/chlorine compared to UV or chlorine alone. The degradation efficiency of atrazine was favorable at a lower pH, but was inhibited in the presence of natural organic matters. Meanwhile, the initial chlorine dosage, alkalinity, and chloride barely influenced the degradation efficiency under neutral pH conditions. The degradation of atrazine by UV/chlorine was inhibited in real waters (i.e., surface water and ground water) compared to in deionized water but was still more effective than UV alone. The oxidation products of atrazine resulting from de-alkylation, dechlorination-hydroxylation, alkylic-hydroxylation, alkylic-oxidation, alkylic-hydroxylation-dehydration, deamination-hydroxylation, and dechlorination-hydrogenation in UV/chlorine process were detected, which were slightly different from those formed in UV/H2O2 (commonly used UV-based advanced oxidation process). Particularly, the yields of three primary transformation products (desethyl-atrazine (DEA), desisopropyl-atrazine (DIA), and desethyl-desisopropyl-atrazine (DEIA)) were comparatively quantified in these two processes. The different trend of them formed in UV/chlorine system (DEA:DIA≈4) compared to that formed in UV/H2O2 system (DEA:DIA≈1) could be ascribed to the different reaction reactivities and mechanisms between HO• and Cl• with atrazine.

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

    Science.gov (United States)

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

    2013-12-01

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

  1. 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.)

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

    Science.gov (United States)

    Drdla, K.; Müller, R.

    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 HNO3 from the gas phase. Using reaction rates on cold binary aerosol in a model of stratospheric chemistry, a chlorine activation threshold temperature, TACL, is derived. At typical stratospheric conditions, TACL is similar in value to TNAT (within 1-2 K), the highest temperature at which nitric acid trihydrate (NAT) can exist. TNAT is still in use to parameterise the threshold temperature for the onset of chlorine activation. However, perturbations can cause TACL to differ from TNAT: TACL is dependent upon H2O and potential temperature, but unlike TNAT is not dependent upon HNO3. Furthermore, in contrast to TNAT, TACL 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 TACL 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 TACL 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, TACL provides a more accurate description of the temperature conditions necessary for chlorine activation and ozone loss in the polar stratosphere than TNAT.

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

    NARCIS (Netherlands)

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

    2008-01-01

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

  4. Fracturing graphene by chlorination: a theoretical viewpoint

    OpenAIRE

    Ijäs, M.; Havu, P.; Harju, A.

    2012-01-01

    Motivated by the recent photochlorination experiment [B. Li et al., ACS Nano 5, 5957 (2011)], we study theoretically the interaction of chlorine with graphene. In previous theoretical studies, covalent binding between chlorine and carbon atoms has been elusive upon adsorption to the graphene basal plane. Interestingly, in their recent experiment, Li et al. interpreted their data in terms of chemical bonding of chlorine on top of the graphene plane, associated with a change from sp2 to sp3 in ...

  5. 42 CFR 35.35 - Unsalable articles.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Unsalable articles. 35.35 Section 35.35 Public... HOSPITAL AND STATION MANAGEMENT Disposition of Articles Produced by Patients § 35.35 Unsalable articles. Articles having no commercial value shall be stored, destroyed, or otherwise disposed of as the officer...

  6. The chlorination of cyclopentanone and cyclohexanone

    NARCIS (Netherlands)

    Maatman, Hendrik

    1980-01-01

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

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

    Science.gov (United States)

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

    1999-12-01

    Electrolyzed salt brine generators hold great promise for water disinfection in small communities and remote locations. Electrolysis cell liquors have been reported to contain chlorine, chlorine dioxide and ozone. High resolution spectrophotometry was used to observe the presence (or absence) of a unique spectral absorbance pattern present in solutions containing 1-2 mg/l chlorine dioxide. PMID:18967802

  8. 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.

  9. Behavior of chlorine in lake water

    International Nuclear Information System (INIS)

    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 107 counts/ml originally came down to 103 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)

  10. Thermal Decomposition Behavior and Non-isothermal Decomposition Reaction of Copper(Ⅱ) Salt of 4-Hydroxy-3,5-dinitropyridine Oxide and Its Application in Solid Rocket Propellant

    Institute of Scientific and Technical Information of China (English)

    CHEN Pei陈沛; ZHAO Feng-Qi赵凤起; LUO Yang罗阳; HU Rong-Zu胡荣祖; GAO Sheng-Li高胜利; ZHENG Yu-Mei郑玉梅; DENG Min-Zhi邓敏智; GAO Yin高茵

    2004-01-01

    The thermal decomposition behavior and kinetic parameters of the exothermic decomposition reactions of the title compound in a temperature-programmed mode have been investigated by means of DSC, TG-DTG and lower rate thermolysis/FTIR. The possible reaction mechanism was proposed. The critical temperature of thermal explosion was calculated. The influence of the title compound on the combustion characteristic of composite modified double base propellant containing RDX has been explored with the strand burner. The results show that the kinetic model function in differential form, apparent activation energy Ea and pre-exponential factor A of the major exothermal explosion of the compound is 312.87 C. The kinetic equation of the major exothermic decomposition process of the title compound at 0.1 MPa could be expressed as:dα/dT=1016.42(1-α)e-2.502× 104/T. As an auxiliary catalyst, the title compound can help the main catalyst lead salt of 4-hydroxy-3,5-dinitropyridine oxide to enhance the burning rate and reduce the pressure exponent of RDX-CMDB propellant.

  11. Partial wave analysis of the reaction p(3.5 GeV+p→pK+Λ to search for the “ppK−” bound state

    Directory of Open Access Journals (Sweden)

    G. Agakishiev

    2015-03-01

    Full Text Available Employing the Bonn–Gatchina partial wave analysis framework (PWA, we have analyzed HADES data of the reaction p(3.5 GeV+p→pK+Λ. This reaction might contain information about the kaonic cluster “ppK−” (with quantum numbers JP=0− and total isospin I=1/2 via its decay into pΛ. Due to interference effects in our coherent description of the data, a hypothetical K¯NN (or, specifically “ppK−” cluster signal need not necessarily show up as a pronounced feature (e.g. a peak in an invariant mass spectrum like pΛ. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra without a contribution of a K¯NN cluster. At a confidence level of CLs=95% such a cluster cannot contribute more than 2–12% to the total cross section with a pK+Λ final state, which translates into a production cross-section between 0.7 μb and 4.2 μb, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.

  12. Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone.

    Science.gov (United States)

    Egan, James M; Rickenbach, Michael; Mooney, Kim E; Palenik, Chris S; Golombeck, Rebecca; Mueller, Karl T

    2006-11-01

    Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.

  13. Chlorine dioxide and by-products in water distribution systems

    OpenAIRE

    Ferreira, Francisco Cardoso

    1991-01-01

    Chlorine dioxide is used as both a pre-oxidant and/or a post-disinfectant in several water treatment plants in the United States. Chlorine dioxide is associated with its byproducts chlorite and chlorate. Chlorine dioxide, chlorine, chlori te and chlorate were sampled in four distribution systems where chlorine dioxide is used for disinfection purposes: Charleston, WV, Columbus, GA, New Castle, PA, and Skagit, WA. The fate of chlorine dioxide and its by-products in dist...

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

    OpenAIRE

    Berman, D.; Hoff, J C

    1984-01-01

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

  15. 21 CFR 173.300 - Chlorine dioxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Chlorine dioxide. 173.300 Section 173.300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Specific Usage Additives § 173.300 Chlorine...

  16. Chlorine

    Science.gov (United States)

    ... Del.icio.us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Updates Subscribe Listen Page last reviewed April ... Del.icio.us Digg Facebook Google Bookmarks Technorati Yahoo MyWeb Download page Subscribe to RSS Get email ...

  17. Behavior and control of chlorine in dyestuff residue incineration

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  18. 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.

  19. 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.)

  20. Kinetics of the oxidation of cylindrospermopsin and anatoxin-a with chlorine, monochloramine and permanganate.

    Science.gov (United States)

    Rodríguez, Eva; Sordo, Ana; Metcalf, James S; Acero, Juan L

    2007-05-01

    Cyanobacteria produce toxins that may contaminate drinking water sources. Among others, the presence of the alkaloid toxins cylindrospermopsin (CYN) and anatoxin-a (ANTX) constitutes a considerable threat to human health due to the acute and chronic toxicity of these compounds. In the present study, not previously reported second-order rate constants for the reactions of CYN and ANTX with chlorine and monochloramine and of CYN with potassium permanganate were determined and the influence of pH and temperature was established for the most reactive cases. It was found that the reactivity of CYN with chlorine presents a maximum at pH 7 (rate constant of 1265 M(-1)s(-1)). However, the oxidation of CYN with chloramine and permanganate are rather slow processes, with rate constants <1 M(-1)s(-1). The first chlorination product of CYN was found to be 5-chloro-CYN (5-Cl-CYN), which reacts with chlorine 10-20 times slower than the parent compound. The reactivity of ANTX with chlorine and chloramines is also very low (k<1M(-1)s(-1)). The elimination of CYN and ANTX in surface water was also investigated. A chlorine dose of 1.5 mg l(-1) was enough to oxidize CYN almost completely. However, 3 mg l(-1) of chlorine was able to remove only 8% of ANTX, leading to a total formation of trihalomethanes (TTHM) at a concentration of 150 microg l(-1). Therefore, chlorination is a feasible option for CYN degradation during oxidation and disinfection processes but not for ANTX removal. The permanganate dose required for CYN oxidation is very high and not applicable in waterworks.

  1. Enhanced Visible Light Photocatalytic Activity of Mesoporous Anatase TiO2 Codoped with Nitrogen and Chlorine

    OpenAIRE

    Xiuwen Cheng; Xiujuan Yu; Zipeng Xing; Lisha Yang

    2012-01-01

    Anatase mesoporous titanium dioxide codoped with nitrogen and chlorine (N-Cl-TiO2) photocatalysts were synthesized through simple one-step sol-gel reactions in the presence of ammonium chloride. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS). XRD results indicated that codoping with nitrogen and chlorine could effectively reta...

  2. Inhibition of explosion-like postirradiation low-temperature chlorination of cyclohexane by loading of solid mixture specimens

    International Nuclear Information System (INIS)

    Reactivity of cryomixtures of solid chlorine and cyclohexane irradiated with gamma-quanta at 77 K up to 10 kGy dose is studied. It is detected that explosion-like chlorination splashes occuring at 143 K can be effectively suppressed by external loading up to several hundred kilopascals. Splash occurrance is connected with spontaneous fracturing stimulating chain reaction propagation with gas phase participation. It is stressed that at low temperatures primary crack flaming should be accompanied by temperature asymmetry

  3. Final chlorine dioxide stage at near-neutral pH for bleaching eucalypt pulp

    OpenAIRE

    Robisnéa A. Ribeiro; Fernando J. B. Gomes; José N. Floriani; Renato A. P. Damásio; Iara F. Demuner; Jorge L. Colodette

    2014-01-01

    It is well known that pH is an important parameter for controlling the eucalyptus pulp bleaching when using the final chlorine dioxide stage, since it affects the effectiveness of the process. Recommendations found in the literature for operating are in the 3.5 to 4.0 range. However, in this paper it was shown that final chlorine dioxide has better performance, with significant brightness gain while also preserving pulp quality, when it is operated at near neutral pH. This result can be expla...

  4. Final chlorine dioxide stage at near-neutral pH for bleaching eucalypt pulp

    Directory of Open Access Journals (Sweden)

    Robisnéa A. Ribeiro

    2014-01-01

    Full Text Available It is well known that pH is an important parameter for controlling the eucalyptus pulp bleaching when using the final chlorine dioxide stage, since it affects the effectiveness of the process. Recommendations found in the literature for operating are in the 3.5 to 4.0 range. However, in this paper it was shown that final chlorine dioxide has better performance, with significant brightness gain while also preserving pulp quality, when it is operated at near neutral pH. This result can be explained by the generation of sodium bicarbonate in situ upon adding carbon dioxide at this stage.

  5. Oxidation of pharmaceuticals by chlorine dioxide in wastewater effluent.

    OpenAIRE

    Alcalá Borao, Raquel

    2015-01-01

    The presence of pharmaceuticals in the environment has raised an emerging interest due to the fact that they pose negative environmental impact and health hazards related to long-term toxicity effects. As conventional treatments are not able to totally remove these substances it is necessary to seek for alternative advanced technologies such as oxidation with chlorine dioxide (ClO2). The objective of this master thesis is thus to find the most optimal dose – reaction time of ClO2 for the oxid...

  6. Theoretical study of the thermochemistry of chlorine oxyfluorides

    Science.gov (United States)

    Sánchez, Hernán R.; Del Pla, Julián

    2016-10-01

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

  7. 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}.

  8. Dechlorination pathways of diverse chlorinated aromatic pollutants conducted by Dehalococcoides sp. strain CBDB1

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Gui-Ning [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Tao, Xue-Qin [School of Environmental Science and Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225 (China); Huang, Weilin [Department of Environmental Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901 (United States); Dang, Zhi, E-mail: chzdang@scut.edu.cn [School of Environmental Science and Engineering, South China University of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Li, Zhong [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Liu, Cong-Qiang [The State Key Lab of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2010-05-15

    Dechlorination of chlorinated aromatic pollutants (CAPs) has become a major issue in recent decades. This paper reported a theoretical indicator for predicting the reductive dechlorination pathways of polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes and chlorophenols transformed by Dehalococcoides sp. strain CBDB1. Density functional theory (DFT) calculations were carried out at the B3LYP/6-31G(d) level for all related CAPs and Mulliken atomic charges on chlorine atoms (Q{sub Cl(n)}) were adopted as the probe of the dechlorination reaction activity. Q{sub Cl(n)} can consistently indicate the main dechlorination daughter products of PCDDs, chlorobenzenes and chlorophenols conducted by strain CBDB1. The dechlorination reaction favors elimination of the chlorine atoms having greater Q{sub Cl(n)} values. The chlorine atom with the greatest Q{sub Cl(n)} value tends preferentially to be eliminated, whereas the chlorine atom with the smallest Q{sub Cl(n)} value tends unlikely to be eliminated or does not react at all. For a series of compounds having similar structure, the maximal Q{sub Cl(n)} of each molecular can be used to predict the possibility of its daughter product(s). In addition, the difference ({Delta}Q{sub Cl(n)}) between the maximal Q{sub Cl(n)} and the next maximal Q{sub Cl(n)} of the same molecule can be used to assess the possibility of formation of multiple dechlorination products.

  9. Extraction of lithium from β-spodumene using chlorination roasting with calcium chloride

    International Nuclear Information System (INIS)

    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 CaCl2 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 CaCl2 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 CaAl2Si2O8, SiO2, and CaSiO3

  10. Evaluating the effects of granular and membrane filtrations on chlorine demand in drinking water

    Institute of Scientific and Technical Information of China (English)

    Veeriah Jegatheesan; Seung Hyun Kim; C. K. Joo; GAO Baoyu

    2009-01-01

    In this study, chlorine decay experiments were conducted for the raw water from Nakdong river that is treated by Chilseo Water Treatment Plant (CWTP) situated in Haman, Korea as well as the effluents from sand and granular activated carbon (GAC) filters of CWTP and fitted using a chlorine decay model. The model estimated the fast and slow reacting nitrogenous as well as organic/inorganic compounds that were present in the water. It was found that the chlorine demand due to fast and slow reacting (FRA and SRA) organic/inorganic substances was not reduced significantly by sand as well as GAC filters. However, the treated effluents from those filters contained FRA and SRA that are less reactive and had small reaction rate constants. For the effluents from microfiltration, ultrafiltration, and nanofiltration the chlorine demand due to FRA and SRA were further reduced but the reaction rate constants were larger compared to those of sand and GAC filter effluents. This has implications in the formation of disinfection by products (DBPs). If DBPs are assumed to form due to the interactions between chlorine and SRA, then it is possible that the DBP formation potential in the effluents from membrane filtrations could be higher than that in the effluents from granular media filters.

  11. Antimicrobial effect of chlorine dioxide on Actinobacillus actinomycetemcomitans in diabetes mellitus rats treated with insulin

    Directory of Open Access Journals (Sweden)

    Tantin Ermawati

    2012-03-01

    Full Text Available Background: Periodontitis is a chronic inflammatory disease of periodontal tissues. Etiology of periodontal disease includes Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans which is the most predominant disease-causing bacteria found in the gingival sulcus. Periodontitis can be exacerbated by the systemic disease, such as diabetes mellitus considered as a metabolic disease characterized by hyperglycemia due to insulin deficiency. Treatment of periodontitis is then required in patients with type I diabetes to avoid radical reaction that can not only cause bleeding, but can also prevent infection, as a result, topical antimicrobial therapy and blood glucose control are required. Topical antimicrobial chlorine dioxide is a disinfectant that is effective in killing A. actinomycetemcomitans. Purpose: This study is aimed to determine the effects of topical antimicrobial chlorine dioxide gel or rinse on the number of A. actinomycetemcomitans in DM rats treated with insulin. Methods: 20 three month old male Wistar rats with weight of 170–200 grams were divided into four groups. First, periodontitis and DM were manipulated into all groups through aloksan injection with dose of 170 mg/kg. Those rats in group I were treated with insulin and chlorine dioxide gel, those in group II were treated with insulin and chlorine dioxide rinse, those in group III were treated with insulin only, and those in group IV were without treatment. In the third and seventh weeks, the number of A. actinomycetemcomitans was measured. The data was tested by using One-Way ANOVA test followed by LSD test. Results: The study showed that chlorine dioxide gel has a greater ability in reducing the number of A. actinomycetemcomitans than chlorine dioxide rinse although both are antimicrobials. Conclusion: It can be concluded that the use of chlorine dioxide gel can more effective to decrease the number of A. actinomycetemcomitans than chlorine dioxide rinse in DM rats

  12. Spatial distribution, temporal variation and risks of parabens and their chlorinated derivatives in urban surface water in Beijing, China.

    Science.gov (United States)

    Li, Wenhui; Gao, Lihong; Shi, Yali; Wang, Yuan; Liu, Jiemin; Cai, Yaqi

    2016-01-01

    The occurrence and distribution of 13 target compounds, including eight parabens, four chlorinated parabens and p-hydroxybenzoic acid (PHBA), were detected in surface water samples at 35 sampling sites in the Beijing River system, China. The surface water samples were collected from the main rivers and lakes in the urban area monthly from July 2013 to June 2014 (except the frozen period). Laboratory analyses revealed that parabens were ubiquitous in the surface water of Beijing. PHBA was the predominant compound in the surface water samples, with the average concentration of 239ngL(-1), followed by the total amount of chlorinated parabens (average 50.1ng/L) and parabens (average 44.3ng/L). It is noteworthy that octylparaben with longer chain was firstly detected in the surface water. Significant difference was observed for paraben concentrations from different sampling sites, and the highest level of parabens was found in the Xiaotaihou River, which was mainly due to the untreated sewage discharge. Seasonal variation of target compounds in the urban surface water was also studied, and parabens exhibited a different temporal variation from chlorinated derivatives. A combination of factors including high residual chlorine level and water temperature as well as intense ultraviolet radiation might enhance the persistence of chlorinated parabens in chlorinated water during the wet season. Risk assessment showed that parabens and their chlorinated derivatives are not likely to produce biological effects on aquatic ecosystems at current levels in the surface water of Beijing.

  13. Implications of treating water containing polynuclear aromatic hydrocarbons with chlorine: a gas chromatographic-mass spectrometric study.

    OpenAIRE

    Oyler, A R; Liukkonen, R J; Lukasewycz, M K; Cox, D A; Peake, D A; Carlson, R M

    1982-01-01

    The products of aqueous chlorination reactions of 1-methylnaphthalene, fluorene, dibenzofuran, anthracene, phenanthrene, 1-methylphenanthrene, fluoranthene, and pyrene have been determined. The conditions employed for these reactions approximated those that might be encountered in water treatment facilities. Reactions at pH greater than 6 tended to produce oxygenated products (epoxides, phenols, quinones, etc.), and reactions at pH less than 6 tended to produce both oxygenated (quinones) and ...

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

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-07-01

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

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

    Directory of Open Access Journals (Sweden)

    S. K. Meilinger

    2002-01-01

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

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

    OpenAIRE

    Taylor, G R; Butler, M

    1982-01-01

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

  17. Global stratospheric chlorine inventories for 2004–2009 from Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS measurements

    Directory of Open Access Journals (Sweden)

    A. T. Brown

    2013-09-01

    Full Text Available We present chlorine budgets calculated between 2004 and 2009 for four latitude bands (70° N–30° N, 30° N–0° N, 0° N–30° S, and 30° S–70° S. The budgets were calculated using ACE-FTS version 3.0 retrievals of the volume mixing ratios (VMRs of 9 chlorine-containing species: CCl4, CFC-12 (CCl2F2, CFC-11 (CCl3F, COCl2, COClF, HCFC-22 (CHF2Cl, CH3Cl, HCl and ClONO2. These data were supplemented with calculated VMRs from the SLIMCAT 3-D chemical transport model (CFC-113, CFC-114, CFC-115, H-1211, H-1301, HCFC-141b, HCFC-142b, ClO and HOCl. The total chlorine profiles are dominated by chlorofluorocarbons (CFCs and halons up to 24 km in the tropics and 19 km in the extra-tropics. In this altitude range CFCs and halons account for 58% of the total chlorine VMR. Above this altitude HCl increasingly dominates the total chlorine profile, reaching a maximum of 95% of total chlorine at 54 km. All total chlorine profiles exhibit a positive slope with altitude, suggesting that the total chlorine VMR is now decreasing with time. This conclusion is supported by the time series of the mean stratospheric total chlorine budgets which show mean decreases in total stratospheric chlorine of 0.38 ± 0.03% per year in the Northern Hemisphere extra-tropics, 0.35 ± 0.07% per year in the Northern Hemisphere tropical stratosphere, 0.54 ± 0.16% per year in the Southern Hemisphere tropics and 0.53 ± 0.12% per year in the Southern Hemisphere extra-tropical stratosphere for 2004–2009. Globally stratospheric chlorine is decreasing by 0.46 ± 0.02% per year. Both global warming potential-weighted chlorine and ozone depletion potential-weighted chlorine are decreasing at all latitudes. These results show that the Montreal Protocol has had a significant effect in reducing emissions of both ozone-depleting substances and greenhouse gases.

  18. Chlorination of organic material in different soil types

    OpenAIRE

    Gustavsson, Malin

    2009-01-01

    Research has shown that formation of chlorinated organic matter occurs naturally and that organic chlorine is as abundant as the chloride ion in organic soils. A large number of organisms are known to convert inorganic chloride (Clin) to organic chlorine (Clorg) (e.g. bacteria, lichen, fungi and algae) and some enzymes associated to these organisms are capable of chlorinating soil organic matter. The aim with the study was to compare organic matter chlorination rates in soils from several dif...

  19. Ozone depletion and chlorine loading potentials

    Science.gov (United States)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  20. Natural and Enhanced Attenuation of Chlorinated Solvents Using RT3D

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christian D.; Truex, Michael J.; Clement, T P.

    2006-07-25

    RT3D (Reactive Transport in 3-Dimensions) is a reactive transport code that can be applied to model solute fate and transport for many different purposes. This document specifically addresses application of RT3D for modeling related to evaluation and implementation of Monitored Natural Attenuation (MNA). Selection of MNA as a remedy requires an evaluation process to demonstrate that MNA will meet the remediation goals. The U.S. EPA, through the Office of Solid Waste and Emergency Response (OSWER) Directive 9200.4?17P, provides the regulatory context for the evaluation and implementation of MNA. In a complementary fashion, the context for using fate and transport modeling as part of MNA evaluation is described in the EPA?s technical protocol for chlorinated solvent MNA, the Scenarios Evaluation Tool for Chlorinated Solvent MNA, and in this document. The intent of this document is to describe (1) the context for applying RT3D for chlorinated solvent MNA and (2) the attenuation processes represented in RT3D, (3) dechlorination reactions that may occur, and (4) the general approach for using RT3D reaction modules (including a summary of the RT3D reaction modules that are available) to model fate and transport of chlorinated solvents as part of MNA or for combinations of MNA and selected types of active remediation.

  1. Contrasting effects of sulfur dioxide on cupric oxide and chloride during thermochemical formation of chlorinated aromatics.

    Science.gov (United States)

    Fujimori, Takashi; Nishimoto, Yoshihiro; Shiota, Kenji; Takaoka, Masaki

    2014-12-01

    Sulfur dioxide (SO2) gas has been reported to be an inhibitor of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) formation in fly ash. However, other research has suggested little or no inhibitory effect of SO2 gas. Although these studies focused on reactions between SO2 gas and gas-phase chlorine (Cl) species, no attention was paid to thermochemical gas-solid reactions. In this study, we found contrasting effects of SO2 gas depending on the chemical form of copper (CuO vs CuCl2) with a solid-phase inorganic Cl source (KCl). Chlorinated aromatics (PCDD/Fs, polychlorinated biphenyls, and chlorobenzenes) increased and decreased in model fly ash containing CuO + KCl and CuCl2 + KCl, respectively, with increased SO2 injection. According to in situ Cu K-edge and S K-edge X-ray absorption spectroscopy, Cl gas and CuCl2 were generated and then promoted the formation of highly chlorinated aromatics after thermochemical reactions of SO2 gas with the solid-phase CuO + KCl system. In contrast, the decrease in aromatic-Cls in a CuCl2 + KCl system with SO2 gas was caused mainly by the partial sulfation of the Cu. The chemical form of Cu (especially the oxide/chloride ratio) may be a critical factor in controlling the formation of chlorinated aromatics using SO2 gas.

  2. 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.

  3. Kinetics of Chlorination of Benzophenone-3 in the Presence of Bromide and Ammonia.

    Science.gov (United States)

    Abdallah, Pamela; Deborde, Marie; Dossier Berne, Florence; Karpel Vel Leitner, Nathalie

    2015-12-15

    The aim of this study was to assess the impact of chlorination on the degradation of one of the most commonly used UV filters (benzophenone-3 (BP-3)) and the effects of bromide and ammonia on the kinetics of BP-3 elimination. Bromide and ammonia are rapidly converted to bromine and chloramines during chlorination. At first, the rate constants of chlorine, bromine and monochloramine with BP-3 were determined at various pH levels. BP-3 was found to react rapidly with chlorine and bromine, with values of apparent second order rate constants equal to 1.25(±0.14) × 10(3) M(-1)·s(-1) and 4.04(±0.54) × 10(6) M(-1)·s(-1) at pH 8.5 for kChlorine/BP-3 and kBromine/BP-3, respectively, whereas low monochloramine reactivity was observed (kNH2Cl/BP-3 = 0.112 M(-1)·s(-1)). To assess the impact of the inorganic content of water on BP-3 degradation, chlorination experiments with different added concentrations of bromide and/or ammonia were conducted. Under these conditions, BP-3 degradation was found to be enhanced in the presence of bromide due to the formation of bromine, whereas it was inhibited in the presence of ammonia. However, the results obtained were pH dependent. Finally, a kinetic model considering 18 reactions was developed using Copasi to estimate BP-3 degradation during chlorination in the presence of bromide and ammonia.

  4. Dechlorination progress of chlorinated organic pollutants degraded by use of ionizing radiation in aqueous solutions

    International Nuclear Information System (INIS)

    Kinetics and mechanisms of dechlorination of chlorinated organic pollutants induced by ionizing radiation were described in this article. The progress on the dechlorination of chlorophenols, polychlorinated biphenyl, trichloroethylene, and perchloroethylene involved in radiolysis was also reviewed. In oxidative condition, hydroxyl radical (·OH) would attack chlorophenol to form ·OH-adducts, which could be dechlorinated gradually. However, chlorophenol can be directly reduced by hydrated electron (eaq-) to release Cl-. It was found that radiolytic degradation of polychlorinated biphenyls in organic solvent would release chlorine atoms gradually by chain reactions and the final products were Cl- and biphenyl. Trichloroethylene and tetrachloroethylene mainly reacted with ·OH with the final products of CO2, HCOOH and HCI. As conclusion, the reductive dechlorination of chlorinated organic pollutants possesses advantages of high degradation efficiency, simple products and relatively low radiation dose compared with the oxidation methods. (authors)

  5. Formation of phosgene during welding activities in an atmosphere containing chlorinated hydrocarbons.

    Science.gov (United States)

    Nieuwenhuizen, M S; Groeneveld, F R

    2000-01-01

    The formation of phosgene During welding activities in an atmosphere containing chlorinated hydrocarbons was investigated. Four different chlorinated hydrocarbons were studied under laboratory conditions. Results are presented as time-averaged phosgene concentration in a total volume of 250 L of air being purged through a 52-L reaction vessel during 20 min. It was found that the formation of phosgene was in the order dichloromethane smoke particles and because of possible nonhomogeneous dispersion of phosgene around the workers. In the case of dichloromethane and carbon tetrachloride the short-term maximum allowable concentration (MAC) of phosgene was not attained at the respective MAC values of the chlorinated hydrocarbons themselves. In the case of trichloroethylene and Freon-22, however, the short-term MAC-value of phosgene was attained even when the concentration was still much below the respective MAC-values.

  6. In vivo measurement of total body chlorine using the 8. 57 MeV prompt de-excitation following thermal neutron capture

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, S.; Plank, L.D.; Knight, G.S.; Hill, G.L. (Auckland Hospital (New Zealand). University Dept. of Surgery)

    1993-01-01

    Prompt gamma neutron activation analysis with [sup 238]Pu/Be sources is used to measure total body chlorine (TBC1) in vivo following the reaction [sup 35]Cl(n,[gamma])[sup 36]Cl. The precision of the method is 4.9% (CV). To assess accuracy an anthropomorphic phantom of minced meat was constructed. Replicate scans of this phantom yielded a mean total chlorine not significantly different from the chemical analysis value. The subject dose equivalent for the activation measurement is less than 0.3 mSv. Mean TBC1 values for 63 male and 107 female healthy volunteers were in broad agreement with predicted amounts based on multiple regression equations developed at other centres from measurements using the delayed gamma approach. Good agreement was observed in 76 volunteers between total body water (TBW) measured by tritium dilution, after correction for non-aqueous hydrogen exchange, and TBW derived from the sum of extracellular water and intracellular water as measured by TBCl and total body potassium (TBK). (Author).

  7. Chlorine dioxide-facilitated oxidation of the azo dye amaranth.

    Science.gov (United States)

    Nadupalli, S; Koorbanally, N; Jonnalagadda, S B

    2011-10-27

    The oxidation reaction of amaranth (trisodium 2-hydroxy-1-(4-sulfonato-1-naphthylazo)naphthalene-3,6-disulfonate or AM(-)) by chlorine dioxide (ClO(2)) in aqueous conditions was investigated in detail. The major reaction products immediately after decolorization of AM(-) were 1,2-naphthoquinone disulfonate sodium salt and 1,4-napthalenedione. The reaction had first-order dependence on both AM(-) and ClO(2). The rate-limiting step involved the reaction between AM(-) and OH(-) ions. The role of hydroxide ion as a catalyst was established. The second-order rate constant increased with pH, from (19.8 ± 0.9) M(-1) s(-1) at pH 7.0, (97.1 ± 2.3) M(-1) s(-1) at pH 8.0 to (132.5 ± 2.8) M(-1) s(-1) at pH 9.0. In the pH range of 6.0-7.5, the catalytic constant for OH(-) ion was 4.0 × 10(9) M(-2) s(-1). The energy and entropy of activation values for the reaction were 50.0 kJ mol(-1) and -658.7 J K(-1) mol(-1), respectively. A probable reaction mechanism was elucidated and was validated by simulations.

  8. [Water disinfection: comparative activities of ozone and chlorine on a wide spectrum of bacteria].

    Science.gov (United States)

    Korol, S; Fortunato, M S; Paz, M; Sanahuja, M C; Lazaro, E; Santini, P; D'Aquino, M

    1995-01-01

    Ozone and chlorine are agents that disinfect by destroying, neutralizing or inhibiting the growth of pathogenic microorganisms. The treatment of drinking water with ozone has shown to be more efficient against spores of Bacillus subtilis. It was observed that the ozone already in dose of 0.35 mg/l produced the reduction of at least 5 log in populations of approximately 1 x 10(6) cells/ml of Escherichia coli, Vibrio cholerae, Salmonella typhi, Yersinia enterocolitica, Pseudomonas aeruginosa, Aeromonas hydrophila, Listeria monocytogenes and Staphylococcus aureus. With a dose of 0.50 mg/l of chlorine, the reduction was much smaller for the tested microorganisms (except Vibrio cholerae), while the effect of 2 mg/l of chlorine was similar to the ozone treatment. For spores of Bacillus subtilis, the reduction observed with ozone concentrations of 0.35 and 0.70 mg/l was of almost 3 log, while no considerable effect was obtained with chlorine in the tested conditions. Our results have shown that both disinfectans were consumed during the treatment period, probably because of the own water demand and the added bacterial mass.

  9. Two-phase ozonation of chlorinated organics

    International Nuclear Information System (INIS)

    In the last few years the amount of research being conducted in the field of single-phase ozonation has grown extensively. However, traditional aqueous-phase ozonation systems are limited by a lack of selective oxidation potential, low ozone solubility in water, and slow intermediate decomposition rates. Furthermore, ozone may decompose before it can be utilized for pollutant destruction since ozone can be highly unstable in aqueous solutions. Naturally occurring compounds such as NaHCO3 also affect ozone reactions by inhibiting the formation of OH-free radicals. To compensate for these factors, excess ozone is typically supplied to a reactor. Since ozone generation requires considerable electric power consumption (16 - 24 kWh/kg of O3), attempts to enhance the ozone utilization rate and stability should lead to more efficient application of this process to hazardous waste treatment. To improve the process, ozonation may be more efficiently carried out in a two-phase system consisting of an inert solvent (saturated with O3) contacted with an aqueous phase containing pollutants. The non-aqueous phase must meet the following criteria: (1) non-toxic, (2) very low vapor pressure, (3) high density (for ease of separation), (4) complete insolubility in water, (5) reusability, (6) selective pollutant extractability, (7) high oxidant solubility, and (8) extended O3 stability. Previously published studies (1) have indicated that a number of fluorinated hydrocarbon compounds fit these criteria. For this project, FC40 (a product of 3M Co.) was chosen due to its low vapor pressure (3 mm Hg) and high specific gravity (1.9). The primary advantages of the FC40 solvent are that it is non-toxic, reusable, has an ozone solubility 10 times that of water, and that 85 % of the ozone remains in the solvent even after 2 hours. This novel two-phase process has been utilized to study the rapid destruction of organic chlorine compounds and organic mixtures

  10. Transformation of acetaminophen during water chlorination treatment: kinetics and transformation products identification.

    Science.gov (United States)

    Cao, Fei; Zhang, Mengtao; Yuan, Shoujun; Feng, Jingwei; Wang, Qiquan; Wang, Wei; Hu, Zhenhu

    2016-06-01

    As a high-consumption drug in the world, acetaminophen (AAP) has been widely detected in natural waters and wastewaters. Its reactivity and the transformation products formed during chlorination may greatly threaten the safety of drinking water. The reaction kinetics of AAP during chlorination was investigated in this study. The results showed that the reaction kinetics could be well described with a kinetics model of -d[AAP]/dt = k app[AAP]t (0.63)[Cl2]t (1.37). The values of apparent rate constant (k app) were dependent on reaction temperature, ammonium, and pH. With the increase in reaction temperature from 5.0 ± 1.0 to 40.0 ± 1.0 °C, the removal efficiency of AAP increased from 60 to 100 %. When ammonium was present in the solution at 2.0 mg/L, the transformation of AAP was inhibited due to the rapid formation of chloramines. The maximum of k app was 0.58 × 10(2) M(-1) · min(-1) at pH 9.0, and the minimum was 0.27 M(-1) · min(-1) at pH 11.0. A low mineralization of AAP (about 7.2 %) with chlorination was observed through TOC analysis, implying the formation of plenty of transformation products during chlorination. The main transformation products, hydroquinone and two kinds of chlorinated compounds, monochlorinated acetaminophen and dichlorinated acetaminophen, were detected in gas chromatography-mass spectrometry analysis.

  11. Transformation of acetaminophen during water chlorination treatment: kinetics and transformation products identification.

    Science.gov (United States)

    Cao, Fei; Zhang, Mengtao; Yuan, Shoujun; Feng, Jingwei; Wang, Qiquan; Wang, Wei; Hu, Zhenhu

    2016-06-01

    As a high-consumption drug in the world, acetaminophen (AAP) has been widely detected in natural waters and wastewaters. Its reactivity and the transformation products formed during chlorination may greatly threaten the safety of drinking water. The reaction kinetics of AAP during chlorination was investigated in this study. The results showed that the reaction kinetics could be well described with a kinetics model of -d[AAP]/dt = k app[AAP]t (0.63)[Cl2]t (1.37). The values of apparent rate constant (k app) were dependent on reaction temperature, ammonium, and pH. With the increase in reaction temperature from 5.0 ± 1.0 to 40.0 ± 1.0 °C, the removal efficiency of AAP increased from 60 to 100 %. When ammonium was present in the solution at 2.0 mg/L, the transformation of AAP was inhibited due to the rapid formation of chloramines. The maximum of k app was 0.58 × 10(2) M(-1) · min(-1) at pH 9.0, and the minimum was 0.27 M(-1) · min(-1) at pH 11.0. A low mineralization of AAP (about 7.2 %) with chlorination was observed through TOC analysis, implying the formation of plenty of transformation products during chlorination. The main transformation products, hydroquinone and two kinds of chlorinated compounds, monochlorinated acetaminophen and dichlorinated acetaminophen, were detected in gas chromatography-mass spectrometry analysis. PMID:26983813

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

    International Nuclear Information System (INIS)

    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

  13. Selective chlorination of natural organic matter: identification of previously unknown disinfection byproducts.

    Science.gov (United States)

    Lavonen, Elin E; Gonsior, Michael; Tranvik, Lars J; Schmitt-Kopplin, Philippe; Köhler, Stephan J

    2013-03-01

    Natural organic matter (NOM) serve as precursors for disinfection byproducts (DBPs) in drinking water production making NOM removal essential in predisinfection treatment processes. We identified molecular formulas of chlorinated DBPs after chlorination and chloramination in four Swedish surface water treatment plants (WTPs) using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Chlorine-containing formulas were detected before and after disinfection and were therefore classified to identify DBPs. In total, 499 DBPs were detected, of which 230 have not been reported earlier. The byproducts had, as a group, significantly lower ratio of hydrogen to carbon (H/C) and significantly higher average carbon oxidation state (COS), double bond equivalents per carbon (DBE/C) and ratio of oxygen to carbon (O/C) compared to Cl-containing components present before disinfection and CHO formulas in samples taken both before and after disinfection. Electrophilic substitution, the proposed most significant reaction pathway for chlorination of NOM, results in carbon oxidation and decreased H/C while O/C and DBE/C is left unchanged. Because the identified DBPs had significantly higher DBE/C and O/C than the CHO formulas we concluded that chlorination of NOM during disinfection is selective toward components with relatively high double bond equivalency and number of oxygen atoms per carbon. Furthermore, choice of disinfectant, dose, and predisinfection treatment at the different WTPs resulted in distinct patterns in the occurrence of DBP formulas.

  14. Atmospheric reactivity of alcohols, thiols and fluoroalcohols with chlorine atoms

    Science.gov (United States)

    Garzon Ruiz, Andres

    Alcohols, thiols and fluoroalcohols are volatile organic compounds (VOCs) which are emitted to the atmosphere from both natural (vegetation, oceans, volcanoes, etc.) and anthropogenic sources (fuels, solvents, wastewater, incinerators, refrigerants, etc.). These pollutants can be eliminated from the troposphere by deposition on the terrestrial surface, direct photolysis or reaction with different tropospheric oxidants. Reactions of VOCs with tropospheric oxidants are involved in the well-known atmospheric phenomenon of photochemical smog or the production of tropospheric ozone. The oxidation of these VOCs in the troposphere is mainly initiated by reaction with OH radicals during the daytime and with NO radicals at night. However, in recent years, the oxidation by chlorine atoms (Cl) has gained great importance in the study of atmospheric reactions because they may exert some influence in the boundary layer, particularly in marine and coastal environments. In general, Cl atoms are much more reactive species than OH and NO; radicals and therefore low concentrations of Cl may compete with OH and NO3 in hydrocarbon oxidation processes. The main source of tropospheric Cl atoms is believed to be the photolysis of chlorine-containing molecules generated by heterogeneous reactions of sea salt aerosols. It has also been proposed that Cl atoms, produced in the photolysis of Cl2 emitted from industrial processes, may enhance hydrocarbon oxidation rates and ozone production in urban environments. In this work, a kinetic, theoretical and mechanistic study of the reaction of several alcohols, thiols, and fluoroalcohols with Cl atoms has been carried out. Pulsed laser photolysis-fluorescence resonance (PLP-RF) technique was used for the kinetic study as a function of temperature and pressure. An environmental chamber-Fourier transform infrared (FTIR) system was also employed in the kinetic studies. Tropospheric lifetimes of these pollutants were estimated using obtained kinetic

  15. Heterogeneous chlorine activation on stratospheric aerosols and clouds in the Arctic polar vortex

    Directory of Open Access Journals (Sweden)

    T. Wegner

    2012-11-01

    Full Text Available Chlorine activation in the Arctic is investigated by examining different parameterizations for uptake coefficients on stratospheric aerosols, high-resolution in-situ measurements and vortex-wide satellite observations. The parameterizations for heterogeneous chemistry on liquid aerosols are most sensitive to temperature with the reaction rates doubling for every 1 K increase in temperature. However, differences between the currently available parameterizations are negligible. For Nitric Acid Trihydrate particles (NAT the major factors of uncertainty are the number density of nucleated particles and different parameterizations for heterogeneous chemistry. These two factors induce an uncertainty that covers several orders of magnitude on the reaction rate. Nonetheless, since predicted reaction rates on liquid aerosols always exceed those on NAT, the overall uncertainty for chlorine activation is small. In-situ observations of ClOx from Arctic winters in 2005 and 2010 are used to evaluate the heterogeneous chemistry parameterizations. The conditions for these measurements proved to be very different between those two winters with HCl being the limiting reacting partner for the 2005 measurements and ClONO2 for the 2010 measurements. Modeled levels of chlorine activation are in very good agreement with the in-situ observations and the surface area provided by Polar Stratospheric Clouds (PSCs has only a limited impact on modeled chlorine activation. This indicates that the parameterizations give a good representation of the processes in the atmosphere. Back-trajectories started on the location of the observations in 2005 indicate temperatures on the threshold for PSC formation, hence the surface area is mainly provided by the background aerosol. Still, the model shows additional chlorine activation during this time-frame, providing cautionary evidence for chlorine activation even in the absence of PSCs. Vortex-averaged satellite

  16. Vortex-wide chlorine activation by a mesoscale PSC event in the Arctic winter of 2009/10

    Science.gov (United States)

    Wegner, Tobias; Pitts, Michael C.; Poole, Lamont R.; Tritscher, Ines; Grooß, Jens-Uwe; Nakajima, Hideaki

    2016-04-01

    In the Arctic polar vortex of the 2009/10 winter temperatures were low enough to allow widespread formation of polar stratospheric clouds (PSCs). These clouds occurred during the initial chlorine activation phase which provided the opportunity to investigate the impact of PSCs on chlorine activation. Satellite observations of gas-phase species and PSCs are used in combination with trajectory modeling to assess this initial activation. The initial activation occurred in association with the formation of PSCs over the east coast of Greenland at the beginning of January 2010. Although this area of PSCs covered only a small portion of the vortex, it was responsible for almost the entire initial activation of chlorine vortex wide. Observations show HCl (hydrochloric acid) mixing ratios decreased rapidly in and downstream of this region. Trajectory calculations and simplified heterogeneous chemistry modeling confirmed that the initial chlorine activation continued until ClONO2 (chlorine nitrate) was completely depleted and the activated air masses were advected throughout the polar vortex. For the calculation of heterogeneous reaction rates, surface area density is estimated from backscatter observations. Modeled heterogeneous reaction rates along trajectories intersecting with the PSCs indicate that the initial phase of chlorine activation occurred in just a few hours. These calculations also indicate that chlorine activation on the binary background aerosol is significantly slower than on the PSC particles and the observed chlorine activation can only be explained by an increase in surface area density due to PSC formation. Furthermore, there is a strong correlation between the magnitude of the observed HCl depletion and PSC surface area density.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  18. Detection and characterization of chlorinated-dioxin ether cleavage function in the bacterium geobacillus midousuji SH2B-J2

    Energy Technology Data Exchange (ETDEWEB)

    Otsuka, Y.; Hoshina, S. [Jikei Univ. School of Medicine, Tokyo (Japan). Dept. of Laboratory Medicine; Nakamura, M.; Hishiyama, S. [Forestry and Forest Products Research Institute, Ibaraki (Japan); Katayama, Y. [Tokyo Univ. of Agriculture and Technology, Koganei (Japan)

    2004-09-15

    As of now, there are no dioxin degrading microorganism reported that can be applied to bioremediation. The reasons for this are that degrading function acquired from comprehensive screening of bacteria that can be grown with a single carbon source using non-chlorinated dioxin does not function against highly chlorinated dioxins, and that although white rot fungus capable of degrading lignin, a plant polyphenol substance, have been reported to reduce chlorinated dioxins, degrading enzyme remain unclear. Geobacillus midousuji SH2B-J2 (J2 strain) that have been separated by Hoshina et al. have shown to reduce highly chlorinated dioxins in incineration fly ash, as well as octa-chlorinated dioxins (OCDD). However, details of its degrading mechanisms remain unclear. Since the J2 strain is capable of reducing even OCDD, it was hypothesized that the initial degradation reaction is intramolecular ether bond cleavage, so J2 strain dioxin degradation mechanism was analyzed for verification.

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

    Institute of Scientific and Technical Information of China (English)

    Meiquan Cai; Liqiu Zhang; Fei Qi; Li Feng

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  1. 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.

    between the deposited saline mineral and the co-existing brine caused the variation of delta sup(37) Cl values in the brine. In general the isotopic fractionation of chlorine in nature indicates enrichment of sup(37)Cl in the solid phase relative to sup(35...

  2. Phase transformations of a talc ore under heated chlorine atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, P., E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Ruiz, M. del C. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis (Argentina); González, J. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Chacabuco y Pedernera, 5700 San Luis (Argentina); Instituto de Ciencias Básicas, Universidad Nacional de Cuyo, Mendoza (Argentina)

    2013-02-20

    Highlights: ► We studied the effect of Cl{sub 2} on minerals present in a talc of ultramafic origin. ► Isothermal and non-isothermal assays were performed in N{sub 2} and Cl{sub 2}–N{sub 2} atmospheres. ► The reagents and the products were analyzed by DTA, XRD, SEM, and EPMA. ► The chlorination produced protoenstatite at 800 °C. ► Calcination of a talc ore in Cl{sub 2} produces more enstatite than thermal treatment in N{sub 2}. - Abstract: The effect of Cl{sub 2} on the phase transformations of the minerals present in a talc (Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}) unpurified with clinochlore (Mg{sub 5}Al{sub 2}Si{sub 3}O{sub 10}(OH){sub 8}), magnesite (MgCO{sub 3}), dolomite (MgCa(CO{sub 3}){sub 2}), hematite (Fe{sub 2}O{sub 3}) and pyrite (FeS{sub 2}) was studied with the purpose of deferricating the mineral and obtaining protoenstatite (MgSiO{sub 3}), which is the basic component of steatite ceramics. Isothermal and non-isothermal assays in N{sub 2} and Cl{sub 2}–N{sub 2} atmospheres were performed using a thermogravimetric device at temperatures between 600 and 980 °C. The reagents and the products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Results obtained showed that the following phenomena were produced in Cl{sub 2}: (a) The transformation of vitreous silica (SiO{sub 2}), from the chlorination reaction of talc, into enstatite (MgSiO{sub 3}) started at about 700 °C, being dolomite the mineral that favored this reaction. At 800 °C, more enstatite was formed as a result of the reaction between vitreous silica not transformed, MgCl{sub 2} and O{sub 2} derived from the chlorination of dolomite and magnesite; then, polymorphic transformation of enstatite into protoenstatite was produced. (b) At about 950 °C, CaCl{sub 2} produced as a result of dolomite chlorination led to the destruction of the protoenstatite

  3. Depletion of chlorine into HCl ice in a protostellar core. The CHESS spectral survey of OMC-2 FIR 4

    Science.gov (United States)

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

    2015-02-01

    Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances <10-5 has not yet been well studied. Aims: Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. Methods: We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H2 hyperfine collisional excitation rate coefficients. Results: A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10-11, a factor of only 10-3 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions: Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of ≲10-10 in most of the protostellar core. We find the [35Cl]/[37Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value. Appendices are available in electronic form at http://www.aanda.org

  4. Investigation of molybdenum pentachloride interaction with chlorine

    International Nuclear Information System (INIS)

    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 ν1(A1'), ν2(A1'), ν5(E'), ν6(E') and ν8(E'') monomer (symmetry D3h) molecules of MoCl5. Interaction of molten molybdenum pentachloride with chlorine at increased (up to 6 MPa) pressures of Cl2 was studied. In Raman spectra of its vapour distillation in liquid chlorine alongside with MoCl5 lines appearance of new lines at 363 and 272 cm-1, similar in their frequency to the ones calculated for the vibrations ν1(A1g) and ν2(Eg) of MoCl6 molecules (symmetry Oh), was observed

  5. Of cabbages and chlorine: cholera in Peru.

    Science.gov (United States)

    1992-07-01

    The low case fatality rates (1%) from the 1991 cholera epidemic in Peru was more a result of including diarrheas of a less virulent etiology than that of cholera. In fact, a study during the early phases of the cholera epidemic in Trujillo, Peru revealed that only 79% of suspected cholera cases were infected with vibrio cholera 01. Further other people contended that the government of Peru did not chlorinate many water supplies because studies by the US Environmental Protection Agency suggested that chlorine increases the cancer risk. It reacts with organic matter to make trihalomethanes. 1 study noted that this risk may explain as many as 700 cases of cancer/year in the US, yet cholera was responsible for nearly 40009 deaths in Latin America the 1st year. Besides in Trujillo, Peru the reason for not chlorinating the water supply was not due to a conscious decision to not do so on the part of the government, but because no funds had been made available to purchase chlorinators and chlorine. This is typical of many towns in developing countries. Further raw fish also played a role in transmitting cholera in Peru. Moreover the study in Trujillo indicated that water stored in containers in the home, and not the water supply, was the most important vehicle of transmission. Nevertheless chlorination of both the water supply and stored water would have prevented cholera transmission. In addition, cabbage irrigated with raw wastewater contributed to cholera transmission in Trujillo. But a concern arises if developing countries follow the advice of WHO of 1st treating wastewater in stabilization ponds. Aquatic blue green algae, other zooplankton, and phytoplankton from a microhabitat suitable for V. cholera. In fact, a study in Peru identified a seasonal pattern of the cholera epidemic with the seasonality of V. cholera non-01 from sewage lagoons in Lima. PMID:1351603

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

    International Nuclear Information System (INIS)

    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

  8. Characterization of unknown iodinated disinfection byproducts during chlorination/chloramination using ultrahigh resolution mass spectrometry.

    Science.gov (United States)

    Wang, Xin; Wang, Juan; Zhang, Yahe; Shi, Quan; Zhang, Haifeng; Zhang, Yu; Yang, Min

    2016-06-01

    Iodinated disinfection byproducts (I-DBPs), formed from the reaction of disinfectant(s) with organic matter in the presence of iodide in raw water, have recently been focused because of their more cytotoxic and genotoxic properties than their chlorinated or brominated analogues. To date, only a few I-DBPs in drinking water have been identified. In this study, C18 solid phase extraction coupled with electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown I-DBPs in chloraminated/chlorinated water spiked with iodide and humic substances. In total, 178 formulas for one-iodine-containing products, 13 formulas for two-iodine-containing products, and 15 formulas for one-chlorine and one-iodine-containing products were detected in the chloraminated water sample, while only 9 formulas for one-iodine-containing products and 6 formulas for one-chlorine and one-iodine-containing products were found in the chlorinated water sample. Most I-DBPs have corresponding chlorine-containing analogues with identical CHO compositions. As indicated by the modified aromaticity index (AImod), in the C18 extracts, more than 68% of the I-DBPs have aromatic structures or polycyclic aromatic structures. This result demonstrates that the use of chloramination as an alternative disinfection method may lead to the formation of abundant species of I-DBPs in the presence of iodide. Thus, the suitability of adopting chloramination as an alternative disinfection method should be reevaluated, particularly when iodide is present in raw water.

  9. Review of chlorination of zirconium dioxide

    International Nuclear Information System (INIS)

    A review of chlorination zirconium dioxide is presented.used semi batch process with vertical reactor, horizontal reactor and fluidized reactor. The feed were zircon dioxide from Aldrich, direct zircon sand and briquette of zircon sand. From the study it is obtained that the best reactor is vertical reactor.It needs modification of chlorination reactor and sublimator to obtain the larger conversion. It is come to reality that zirconium tetrachloride preparation by process is significant with zirconium tetrachloride from Aldrich. It needs the sequel research to get the best result of process. (author)

  10. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

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

  11. Chlorinated organic compounds produced by Fusarium graminearum.

    Science.gov (United States)

    Ntushelo, Khayalethu

    2016-06-01

    Fusarium graminearum, a pathogen of wheat and maize, not only reduces grain yield and degrades quality but also produces mycotoxins in the infected grain. Focus has been on mycotoxins because of the human and animal health hazards associated with them. In addition to work done on mycotoxins, chemical profiling of F. graminearum to identify other compounds produced by this fungus remains critical. With chemical profiling of F. graminearum the entire chemistry of this fungus can be understood. The focus of this work was to identify chlorinated compounds produced by F. graminearum. Various chlorinated compounds were detected and their role in F. graminearum is yet to be understood. PMID:27165533

  12. Attacks of Asthma due to Chlorinized Water: Case Report

    OpenAIRE

    Murat Eyup Berdan; Ercan Gocgeldi; Sami Ozturk; Ali Kutlu

    2008-01-01

    The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been reported. But, attacks of asthma which is related to chlorinized water is rare. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming and a worker can exposed to chlorine while he or she was using water with chlorine at home. We describe a persistent increase in nonspecific bronchial hyperresponsiveness following chronic exposure ...

  13. Sulfur-35 foam flotation kinetics

    International Nuclear Information System (INIS)

    A kinetic is studied of the foam flotation of the trace amounts of 35S with the use of quartenary ammonium salts (QAS), namely alkylbenzyldimethylammoniumchloride and alkyltrimethylammoniumchloride with respect to the pH value of the solution. The rate of the carrying-out QAS and 35S to the foam layer depends on the solution ionic strength, the rate of the isotope extraction being highest and that of the collector - the lowest in the neutral region of pH. The kinetics of the 35S and QAS foam flotation can be described by the first-order reaction equations. The process rate constants have been calculated at various pH values

  14. Removing 3,5-Dichlorophenol from Wastewater by Alternative Adsorbents

    OpenAIRE

    Kobetičová Hana; Galbičková Blanka; Ševčíková Janka; Soldán Maroš

    2014-01-01

    The main objective of this paper is to evaluate an efficiency of 3,5 - dichlorophenol removal from wastewater by using alternative adsorbents. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and also atoms of chlorine. Chlorophenols may have a huge isomere variety that means there are differences in their chemical and physical properties. Due to their toxicity it is necessary to remove them from waste water and in this paper an alternative way of such process is de...

  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.

    1997-01-01

    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 chlorinate

  16. Chlorine Gas: An Evolving Hazardous Material Threat and Unconventional Weapon

    Directory of Open Access Journals (Sweden)

    Jones, Robert MD

    2010-05-01

    Full Text Available Chlorine gas represents a hazardous material threat from industrial accidents and as a terrorist weapon. This review will summarize recent events involving chlorine disasters and its use by terrorists, discuss pre-hospital considerations and suggest strategies for the initial management for acute chlorine exposure events. [West J Emerg Med. 2010; 11(2:151-156.

  17. Formation of brominated trihalomethanes in chlorinated drinking-water from Lake Constance

    International Nuclear Information System (INIS)

    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 CHCl3 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 CHCl3- and the CHBrCl2-formation, but there was no effect on the formation of CHBr2Cl and CHBr3. However, the total THM-concentration in the drinking water never exceeded the German drinking water standard of 10 μg/L. (orig.)

  18. 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.

  19. A Straightforward Route to Tetrachloroauric Acid from Gold Metal and Molecular Chlorine for Nanoparticle Synthesis

    Directory of Open Access Journals (Sweden)

    Shirin R. King

    2015-08-01

    Full Text Available Aqueous solutions of tetrachloroauric acid of high purity and stability were synthesised using the known reaction of gold metal with chlorine gas. The straightforward procedure developed here allows the resulting solution to be used directly for gold nanoparticle synthesis. The procedure involves bubbling chlorine gas through pure water containing a pellet of gold. The reaction is quantitative and progressed at a satisfactory rate at 50 °C. The gold(III chloride solutions produced by this method show no evidence of returning to metallic gold over at least twelve months. This procedure also provides a straightforward method to determine the concentration of the resulting solution using the initial mass of gold and volume of water.

  20. Chlorine fate and transport in drinking water distribution systems: Results from experimental and modeling studies

    Institute of Scientific and Technical Information of China (English)

    Robert M. Clark

    2011-01-01

    It has become generally accepted that water quality can deteriorate in a distribution system through microbiological and chemical reactions in the bulk phase and/or at the pipe wall.The most serious aspect of water quality deterioration in a network is the loss of the disinfectant residual that can weaken the barrier against microbial contamination.Studies have suggested that one factor contributing to the loss of disinfectant residuals is the reaction between bulk phase disinfectants and pipe wall material.Free chlorine loss in corroded metal and PVC pipes,subject to changes in velocity,was assessed during an experiment conducted under controlled conditions in a specially constructed pipe loop located at the US Environmental Protection Agency's (EPA's) Test and Evaluation (T&E) Facility in Cincinnati,Ohio (USA).These studies demonstrated that in older unlined metal pipes,the loss of chlorine residual increases with velocity but that wall demand in PVC was negligible.

  1. Transformation of avobenzone in conditions of aquatic chlorination and UV-irradiation.

    Science.gov (United States)

    Trebše, Polonca; Polyakova, Olga V; Baranova, Maria; Kralj, Mojca Bavcon; Dolenc, Darko; Sarakha, Mohamed; Kutin, Alexander; Lebedev, Albert T

    2016-09-15

    Emerging contaminants represent a wide group of the most different compounds. They appear in the environment at trace levels due to human activity. Most of these compounds are not yet regulated. Sunscreen UV-filters play an important role among these emerging contaminants. In the present research the reactions of 4-tert-butyl-4'-methoxydibenzoylmethane (avobenzone), the most common UV filter in the formulation of sunscreens, were studied under the combined influence of active chlorine and UV-irradiation. Twenty five compounds were identified by GC/MS as transformation products of avobenzone in reactions of aquatic UV-irradiation and chlorination with sodium hypochlorite. A complete scheme of transformation of avobenzone covering all the semivolatile products is proposed. The identification of the two primary chlorination products (2-chloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione and 2,2-dichloro-1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-1,3-propanedione) was confirmed by their synthesis and GC/MS and NMR analysis. Although the toxicities of the majority of these products remain unknown substituted chlorinated phenols and acetophenones are known to be rather toxic. Combined action of active chlorine and UV-irradiation results in the formation of some products (chloroanhydrides, chlorophenols) not forming in conditions of separate application of these disinfection methods. Therefore caring for people «well-being» it is of great importance to apply the most appropriate disinfection method. Since the primary transformation products partially resist powerful UV-C irradiation they may be treated as stable and persistent pollutants. PMID:27258620

  2. Production and distribution of chlorination by-products in the cooling water system of a coastal power station

    International Nuclear Information System (INIS)

    Employing chlorination as antifouling agent in cooling water circuits of coastal power plants can lead to the production of chlorination by-products (CBP), mainly due to chlorine's reactions with the organic compounds present in natural seawater. Important among the by products are trihalomethane, haloacetonitriles, halo acetic acids, halo phenols etc., with trihalomethanes (THM) generally being the predominant compounds. The THM species that are commonly observed are chloroform, mono bromodichloromethane, dibromochloro-methane and bromoform. The present work was carried out to understand the production and distribution of chlorination by products (mainly trihalomethanes) in the cooling water systems of Madras Atomic Power Station (MAPS). Field studies were carried out in which samples collected from the intake, forebay pump house, out fall point and mixing point were analysed for THM using gas chromatograph with electron capture detector. The results showed that bromoform was the dominant THM formed as a result of chlorination, followed by dibromochloromethane. Mono bromodichloromethane and chloroform were not observed in seawater throughout the study period. Moreover, no THM could be detected at the intake point. The total THM values at other stations ranged between 25-250 μgL-1, the highest values were observed at the process seawater pump outlet and the lowest at the mixing point. The concentrations of CBP's formed were found to be related to the chlorine residuals measured. In addition, laboratory experiments were carried out to understand CBP formation as a function of chlorine dose and contact time. Chlorine doses ranging from 1 to 10 mgL-1 were added to unfiltered seawater and the various THMs formed were analysed after different time intervals. The results confirmed that bromoform was the dominant THM species, followed by dibromochloromethane, as observed in the field studies. As the chlorine doses increased, the other THMs, namely, mono

  3. Evaluating and elucidating the formation of nitrogen-contained disinfection by-products during pre-ozonation and chlorination.

    Science.gov (United States)

    Chiang, Pen-Chi; Chang, E-E; Chuang, Chao-Chin; Liang, Chung-Huei; Huang, Chin-Pao

    2010-06-01

    The effects of pre-ozonation on the formation of haloacetonitriles (HANs), trichloronitromethane (TCNM), and haloketones (HKs) during chlorination were evaluated. Ozone dose used in this study was 8.0, 10.0 and 25.0 mg O(3)/min. Results showed high UV(254) reduction (>80%) and relatively low dissolved organic carbon removal (40-70%) after ozonation, indicating that ozone might change significantly the chemical properties of natural organic matter presented in the raw water. Undesired ozonation by-products such as aldehydes and ketones were also formed during ozonation. At high ozone dose of 25.0 mg O(3)/min, the formation of dichloroacetonitrile and bromochloroacetonitrile were reduced significantly. Chlorination of the ozonated water formed high concentration of TCNM and HKs were 8-10 and 31-48 microg/L, respectively. It was also found that continuous hydrolysis at longer reaction time rapidly decreased the formation of HKs. Ozonation prior to chlorination practice exhibited a negative effect on TCNM and HKs reduction. A model based on the dissolved organic carbon and chlorine decay was developed not only for determining the reaction rate constants, e.g. formation and hydrolysis of HANs, HKs and TCNM, but also for interpreting the mechanisms of formation and hydrolysis for HANs, HKs and TCNM during the chlorination of natural organic matter.

  4. Chlorinated organic compounds in urban river sediments

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  5. 46 CFR 151.50-31 - Chlorine.

    Science.gov (United States)

    2010-10-01

    ... desired rate of discharge, provided the air or gas is oil-free and thoroughly dried by passing it over activated aluminum oxide, silica gel, or other acceptable drying agent, and provided the supply pressure is...-resistant to chlorine in either the gas or liquid phase. Cast or malleable iron shall not be used....

  6. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    , 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. Investigating the Environment-dependent Photophysics of Chlorine Dioxide With Resonance Raman Intensities

    OpenAIRE

    Esposito, Anthony P.; Foster, Catherine E.; Reid, Philip J.

    1999-01-01

    The condensed-phase excited-state reaction dynamics of chlorine dioxide are investigated using resonance Raman intensity analysis. Absolute Raman intensities are measured on resonance with the 2B2–2A2 electronic transition and used to establish the excited-state structural evolution which occurs on the 2A2 surface following photoexcitation. Analysis of the intensities demonstrates that excited-state relaxation occurs along all three normal coordinates; however, only modest evolution is observ...

  8. Some considerations in the handling of fluorine and the chlorine fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, R.L. Jr.; Barber, E.J.

    1979-07-10

    This paper reviews many considerations in the safe handling of fluorine and the chlorine fluorides. The physical, chemical, and toxicological properties of the materials are reviewed. Proper choice of materials of construction and materials in contact with the active gases are considered. The survey includes safe practices in design and operation of experiments and processes. Soda lime traps and caustic scrubbing are reviewed for fluorine disposal methods. Finally some explosive reactions and explosive situations are discussed.

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

    OpenAIRE

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

    2011-01-01

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

  10. 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 methan

  11. Transformation of Organophosphorus Pesticides in the Presence of Aqueous Chlorine: Kinetics, Pathways, and Structure-Activity Relationships

    Science.gov (United States)

    The fate of organophosphorus (OP) pesticides in the presence of aqueous chlorine was investigated under simulated drinking water treatment conditions. Intrinsic rate coefficients were found for the reaction of hypochlorous acid (kHOCl,OP) and hypochlorite ion (kOCl,OP) for eight...

  12. Halogenase-Inspired Oxidative Chlorination Using Flavin Photocatalysis.

    Science.gov (United States)

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

    2016-04-18

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

  13. Effect of nitrite on the formation of halonitromethanes during chlorination of organic matter from different origin

    Science.gov (United States)

    Hong, Huachang; Qian, Lingya; Xiao, Zhuoqun; Zhang, Jianqing; Chen, Jianrong; Lin, Hongjun; Yu, Haiying; Shen, Liguo; Liang, Yan

    2015-12-01

    Occurrence of halonitromethanes (HNMs) in drinking water has been a public concern due to the potential risks to human health. Though quite a lot of work has been carried out to understand the formation of HNMs, the relationship between HNMs formation and the nitrite remains unclear. In this study, the effects of nitrite on the formation of HNMs during chlorination of organic matter from different origin were assessed. Organic matter (OM) derived from phoenix tree (fallen leaves: FLOM; green leaves: GLOM) and Microcystis aeruginosa (intracellular organic matter: IOM) were used to mimic the allochthonous and autochthonous organic matter in surface water, respectively. Results showed that HNMs yields were significantly enhanced with the addition of nitrite, and the highest enhancement was observed for FLOM, successively followed by GLOM and IOM, suggesting that the contribution of nitrite to HNMs formation was positively related with SUVA (an indicator for aromaticity) of OM. Therefore, the nitrite contamination should be strictly controlled for the source water dominated by allochthonous OM, which may significantly reduce the formation of HNMs during chlorination. Moreover, given a certain nitrite level, the higher pH resulted in higher stimulation of HNM formation, yet the chlorine dose (always added in excess resulting in residual reactive chlorine), reaction time and temperature did not show obvious influence.

  14. Simultaneous Recovery of Hydrogen and Chlorine from Industrial Waste Dilute Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    N. Paidimarri

    2016-01-01

    Full Text Available Recovery of chlorine from byproduct HCl has inevitable commercial importance in industries lately because of insufficient purity or too low concentration to recycle it. Instead it is being neutralized in industries before disposing to meet stringent environmental conditions. Although recovery through catalytic oxidation processes is studied since the 19th century, their high operating conditions combined with sluggish reaction kinetics and low single pass conversions make electrolysis a better alternative. The present motive of this work is to develop a novel electrolysis process which in contrast to traditional processes effectively recovers both hydrogen and chlorine from dilute HCl. For this, an electrolytic cell with an Anionic Exchange Membrane has been designed which only allows the passage of chlorine anions from catholyte to anolyte separating the gasses in a single step. The catholyte can be as low as 3.59 wt% because of fixed anolyte concentration of 1.99 wt% which minimizes oxygen formation. Preliminary results show that the simultaneous recovery of hydrogen and chlorine is possible with high conversion up to 98%. The maximum current density value for 4.96 cm2 membrane surface area (70% active surface area is 2.54 kAm−2, which is comparable with reported commercial processes. This study is expected to be useful for process intensification of the same in a continuous process environment.

  15. 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. PMID:864787

  16. Study of nuclear reactions producing 36Cl by micro-AMS

    Science.gov (United States)

    Luís, H.; Jesus, A. P.; Fonseca, M.; Cruz, J.; Galaviz, D.; Franco, N.; Alves, E.

    2016-01-01

    36Cl is one of several short to medium lived isotopes (as compared to the earth age) whose abundances at the earlier solar system may help to clarify its formation process. There are two generally accepted possible models for the production of this radionuclide: it originated from the ejecta of a nearby supernova (where 36Cl was most probably produced in the s-process by neutron irradiation of 35Cl) and/or it was produced by in-situ irradiation of nebular dust by energetic particles (mostly, p, a, 3He -X-wind irradiation model). The objective of the present work is to measure the cross section of the 37Cl(p,d)36Cl and 35Cl(d,p)36Cl nuclear reactions, by measuring the 36Cl content of AgCl samples (previously bombarded with high energy protons and deuterons) with AMS, taking advantage of the very low detection limits of this technique for chlorine measurements. For that, the micro-AMS system of the LF1/ITN laboratory had to be optimized for chlorine measurements, as to our knowledge this type of measurements had never been performed in such a system (AMS with micro-beam). Here are presented the first results of these developments, namely the tests in terms of precision and reproducibility that were done by comparing AgCl blanks irradiated at the Portuguese National Reactor with standards produced by the dilution of the NIST SRM 4943 standard material.

  17. Biodegradation Kinetics of 1,4-Dioxane in Chlorinated Solvent Mixtures.

    Science.gov (United States)

    Zhang, Shu; Gedalanga, Phillip B; Mahendra, Shaily

    2016-09-01

    This study investigated the impacts of individual chlorinated solvents and their mixtures on aerobic 1,4-dioxane biodegradation by Pseudonocardia dioxanivorans CB1190. The established association of these co-occurring compounds suggests important considerations for their respective biodegradation processes. Our kinetics and mechanistic studies demonstrated that individual solvents inhibited biodegradation of 1,4-dioxane in the following order: 1,1-dichloroethene (1,1-DCE) > cis-1,2-diochloroethene (cDCE) > trichloroethene (TCE) > 1,1,1-trichloroethane (TCA). The presence of 5 mg L(-1) 1,1-DCE completely inhibited 1,4-dioxane biodegradation. Subsequently, we determined that 1,1-DCE was the strongest inhibitor of 1,4-dioxane biodegradation by bacterial pure cultures exposed to chlorinated solvent mixtures as well as in environmental samples collected from a site contaminated with chlorinated solvents and 1,4-dioxane. Inhibition of 1,4-dioxane biodegradation rates by chlorinated solvents was attributed to delayed ATP production and down-regulation of both 1,4-dioxane monooxygenase (dxmB) and aldehyde dehydrogenase (aldH) genes. Moreover, increasing concentrations of 1,1-DCE and cis-1,2-DCE to 50 mg L(-1) respectively increased 5.0-fold and 3.5-fold the expression of the uspA gene encoding a universal stress protein. In situ natural attenuation or enhanced biodegradation of 1,4-dioxane is being considered for contaminated groundwater and industrial wastewater, so these results will have implications for selecting 1,4-dioxane bioremediation strategies at sites where chlorinated solvents are present as co-contaminants. PMID:27486928

  18. Antiradiation effectiveness of the chlorine C

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. InCl{sub 3}/NaClO: a reagent for allylic chlorination of terminal olefins

    Energy Technology Data Exchange (ETDEWEB)

    Pisoni, Diego S.; Gamba, Douglas; Fonseca, Carlos V.; Costa, Jesse S. da; Petzhold, Cesar L.; Oliveira, Eduardo R. de; Ceschi, Marco A. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Quimica]. E-mail: mceschi@iq.ufrgs.br

    2006-03-15

    Indium trichloride promotes the chlorination of terminal olefins in the presence of sodium hypochlorite with good results. Carvone was chosen as a model compound to examine some of the general features of this reaction, such as stoichiometry, temperature, reaction time and product conversion. Treatment of {beta}-pinene with sodium hypochlorite in the presence of indium trichloride resulted in a facile rearrangement to selectively yield perillyl chloride, which is an important precursor for C-7 oxygenated limonenes. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

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

    International Nuclear Information System (INIS)

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

  3. Bacterial responses to reactive chlorine species.

    Science.gov (United States)

    Gray, Michael J; Wholey, Wei-Yun; Jakob, Ursula

    2013-01-01

    Hypochlorous acid (HOCl), the active ingredient of household bleach, is the most common disinfectant in medical, industrial, and domestic use and plays an important role in microbial killing in the innate immune system. Given the critical importance of the antimicrobial properties of chlorine to public health, it is surprising how little is known about the ways in which bacteria sense and respond to reactive chlorine species (RCS). Although the literature on bacterial responses to reactive oxygen species (ROS) is enormous, work addressing bacterial responses to RCS has begun only recently. Transcriptomic and proteomic studies now provide new insights into how bacteria mount defenses against this important class of antimicrobial compounds. In this review, we summarize the current knowledge, emphasizing the overlaps between RCS stress responses and other more well-characterized bacterial defense systems, and identify outstanding questions that represent productive avenues for future research. PMID:23768204

  4. Behavioral toxicology, risk assessment, and chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

  5. Chlorine diffusion in CdTe

    Energy Technology Data Exchange (ETDEWEB)

    Sadaiyandi, K.; Ramachandran, K. (School of Physics, Madurai Kamaraj Univ. (India))

    1991-06-01

    The experimental results of chlorine diffusion in CdTe reveal that the dominant mechanism for diffusion is through neutral defect pair such as (V{sub Cd}V{sub Te}){sup *}. Here, theoretical calculations are carried out for all the possible mechanisms such as single vacancy, single interstitial, neutral defect pair, and Frenkel defect pair. The results suggest that the most possible mechanism for Cl diffusion in CdTe is that through neutral defect pair, supporting the experiment. (orig.).

  6. Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

    Science.gov (United States)

    Thompson, C. R.; Shepson, P. B.; Liao, J.; Huey, L. G.; Apel, E. C.; Cantrell, C. A.; Flocke, F.; Orlando, J.; Fried, A.; Hall, S. R.; Hornbrook, R. S.; Knapp, D. J.; Mauldin, R. L., III; Montzka, D. D.; Sive, B. C.; Ullmann, K.; Weibring, P.; Weinheimer, A.

    2015-08-01

    The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, observation of snowpack photochemical production of I2. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OASIS field campaign in Barrow, Alaska. We simulated a 7-day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our Base Model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO2 and RO2, with organic compounds serving as the primary reaction partner for Cl atoms. The results of this work highlight the need for future

  7. The influence of chlorine on the fate and activity of alkali metals during the gasification of wood

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-08-01

    Chlorine clearly inhibits the CO{sub 2}-gasification reaction of charcoal at 800{sup o}C. From this and other observations the picture emerges that the reduction in the gasification reactivity of the charcoal is intimately related to the deactivation of the catalytically active alkali metals residing in the wood due to the formation of the chloride salt. It is argued that the heavy metal chlorides will likely transfer the chlorine to the indigenous alkali metals during the pyrolysis stage of the wood. The fate of the thus formed alkali metal chlorides can then be either their removal from the sample (evaporation), or, when present at the gasification stage, re-activation (i.e., de-chlorination) under our gasification conditions. (author) 3 figs., 4 refs.

  8. Radiolytic degradation of chlorinated hydrocarbons in water

    International Nuclear Information System (INIS)

    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 γ rays. Concentrations of methane, ethane, CO, CO2, H2, and O2 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, CO2, H2, and Cl- concentrations increased with the radiation dose and the sample concentration. On the other hand, O2 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 CO2. This resulted in a low decomposition ratio. Addition of H2O2 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)

  9. Predicting bromide incorporation in a chlorinated indoor swimming pool.

    Science.gov (United States)

    Chowdhury, Shakhawat; Mazumder, Abu Jafar; Husain, Tahir

    2016-06-01

    The water in and air above swimming pools often contain high levels of disinfection byproducts (DBPs) due to chemical reactions between chlorine- or bromine-based disinfectants and organic/inorganic matter in the source water and released from swimmers. Exposure to these DBPs, though inevitable, can pose health threats to humans. In this study, DBPs in tap water (S1), and water from a chlorinated indoor swimming pool before (S2) and after swimming (S3) were measured. The brominated species constituted the majority of DBPs formed in S1, S2, and S3. Trihalomethanes (THMs) in S3 was 6.9 (range 2.9-11.1) and 1.4 (range 0.52-2.9) times those in S1 and S2, respectively; and the haloacetic acids (HAAs) in S3 was 4.2 (range 2.5-7.5) and 1.2 (range 0.6-2.6) times those in S1 and S2, respectively. The mean THMs in air above the swimming pool before (S2-A) and after swimming (S3-A) were 72.2 and 93.0 μg/m(3), respectively, and their ranges were 36.3-105.8 and 44.1-133.6 μg/m(3), respectively. The average percentages of bromide incorporation (BI) into THMs in S1, S2, and S3 were 3.0, 9.3, and 10.6 %, respectively; and the BI into HAAs in S1, S2, and S3 were 6.6, 12.0, and 12.2 %, respectively. Several models were trained for predicting the BI into THMs and HAAs. The results indicate that additional information is required to develop predictive models for BI in swimming pools.

  10. Parallel oxygen and chlorine evolution on Ru1-xNixO2-y nanostructured electrodes

    International Nuclear Information System (INIS)

    Nanocrystalline materials with chemical composition corresponding to formula Ru1-xNixO2-y (0.02 1-xNixO2-y with respect to parallel oxygen (oxygen evolution reaction, OER) and chlorine (chlorine evolution reaction, CER) evolution in acidic media was studied by voltammetry combined with differential electrochemical mass spectrometry (DEMS). The DEMS data indicate a significant decrease of the over-voltage for chlorine evolution with respect to that of pure RuO2. The oxygen evolution is slightly hindered. The increasing Ni content affects the electrode material activity and selectivity. The overall material's activity increases with increasing Ni content. The activity of the Ru-Ni-O oxides towards Cl2 evolution shows a distinguished maximum for material containing 10% of Ni. Further increase of Ni content results in suppression of Cl2 evolution in favor of O2 evolution. A model reflecting the cation-cation interactions resulting from Ni-doping is proposed to explain the observed trends in electrocatalytic behavior

  11. Synergetic inhibition of thermochemical formation of chlorinated aromatics by sulfur and nitrogen derived from thiourea: Multielement characterizations.

    Science.gov (United States)

    Fujimori, Takashi; Nakamura, Madoka; Takaoka, Masaki; Shiota, Kenji; Kitajima, Yoshinori

    2016-07-01

    Nitrogen and sulfur (N/S)-containing compounds inhibit the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in thermal processes. However, few studies have examined the inhibition mechanisms of N/S-containing compounds. In the present study, we focused on thiourea [(NH2)2CS] as such a compound and investigated its inhibition effects and mechanisms. The production of PCDD/Fs, polychlorinated biphenyls (PCBs), and chlorobenzenes (CBzs) were inhibited by >99% in the model fly ash in the presence of 1.0% thiourea after heating at 300°C. Experimental results using real fly ash series were indicative of the thermal destruction of these chlorinated aromatics by thiourea. Multielement characterization using K-edge X-ray absorption fine structures of copper, chlorine, sulfur, nitrogen, and carbon revealed three possible inhibition paths, namely, (a) sulfidization of the copper catalyst to CuS, Cu2S, and CuSO4; (b) blocking the chlorination of carbon via the reaction of chlorine with N-containing compounds to generate ammonium chloride and other minor compounds; and (c) changing the carbon frame involved in attacking the carbon matrix by sulfur and nitrogen. Thus, thiourea plays a role as a sulfur and nitrogen donor to achieve multiple and synergistic inhibition of chlorinated aromatics. Our results suggest that other N/S-containing inhibitors function based on similar mechanisms. PMID:26954475

  12. Synergetic inhibition of thermochemical formation of chlorinated aromatics by sulfur and nitrogen derived from thiourea: Multielement characterizations.

    Science.gov (United States)

    Fujimori, Takashi; Nakamura, Madoka; Takaoka, Masaki; Shiota, Kenji; Kitajima, Yoshinori

    2016-07-01

    Nitrogen and sulfur (N/S)-containing compounds inhibit the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in thermal processes. However, few studies have examined the inhibition mechanisms of N/S-containing compounds. In the present study, we focused on thiourea [(NH2)2CS] as such a compound and investigated its inhibition effects and mechanisms. The production of PCDD/Fs, polychlorinated biphenyls (PCBs), and chlorobenzenes (CBzs) were inhibited by >99% in the model fly ash in the presence of 1.0% thiourea after heating at 300 °C. Experimental results using real fly ash series were indicative of the thermal destruction of these chlorinated aromatics by thiourea. Multielement characterization using K-edge X-ray absorption fine structures of copper, chlorine, sulfur, nitrogen, and carbon revealed three possible inhibition paths, namely, (a) sulfidization of the copper catalyst to CuS, Cu2S, and CuSO4; (b) blocking the chlorination of carbon via the reaction of chlorine with N-containing compounds to generate ammonium chloride and other minor compounds; and (c) changing the carbon frame involved in attacking the carbon matrix by sulfur and nitrogen. Thus, thiourea plays a role as a sulfur and nitrogen donor to achieve multiple and synergistic inhibition of chlorinated aromatics. Our results suggest that other N/S-containing inhibitors function based on similar mechanisms.

  13. GREENER REACTIONS UNDER SOLVENT FREE CONDITIONS

    Directory of Open Access Journals (Sweden)

    Hiren M. Marvaniya

    2011-06-01

    Full Text Available The toxicity and volatile nature of many organic solvents, particularly chlorinated hydrocarbons that are widely used in huge amounts for organic reactions have posed a serious threat to the environment. Thus, design of solventless catalytic reaction has received tremendous attention in recent times in the area of green synthesis. A solvent-free or solid state reaction may be carried out using the reactants alone or incorporating them in clays, zeolites, silica, alumina or other matrices to achieve high degree of stereoselectivity in the products, to reduce byproducts, to maximize rate of reaction. We illustrate the environmentally benign approach to 1,2-Oxazine-2- oxides, Michael addition, Wohl–Ziegler reaction, Acylation, Heck reaction, Tishchenko reaction, Diels– Alder reaction, Reformatsky and Luche Reaction, Oxidative coupling Reaction, Synthesis of chalcones, Synthesis of Dihydropyrimidinones

  14. Smelting chlorination method applied to removal of copper from copper slags

    Institute of Scientific and Technical Information of China (English)

    李磊; 王华; 胡建杭

    2015-01-01

    In order to reasonably utilize the iron resources of copper slags, the smelting chlorination process was used to remove copper from copper slags. Higher holding temperature and O2 flow rate are beneficial to increasing copper removal rate. However, the Cu2O mode is formed by the reaction of surplus O2 and CuCl with O2 flow rate increasing over 0.4 L/min, causing CuCl volatilization rate and copper removal rate to decrease. The resulting copper removal rate of 84.34%is obtained under the optimum conditions of holding temperature of 1573 K, residence time of 10 min, CaCl2 addition amount of 0.1 (mass ratio of CaCl2 and the copper slag) and oxygen flow rate of 0.4 L/min. The efficient removal of copper from copper slags through chlorination is feasible.

  15. Kinetics of recovering germanium from lignite ash with chlorinating roasting methods

    Institute of Scientific and Technical Information of China (English)

    ZHU Guocai; WANG Jingyan; CHENG Zhuo; ZHAO Yuna

    2008-01-01

    A process of recovering Ge by chlorinating roasting was put forward. GeCl4 was separated and recovered from lignite ash because of its low boiling point. Kinetic analysis indicates that the chlorinating roasting process fits with the unreacted-core shrinking model and the reaction rate equation corresponds to 1-2a/3-(1-a)2/3 =kt. The apparent activation energy Ea is calculated to be 22.36 kJ·mol-1. The diffusion of product layer serves as the rate-controlling step in this process. When the roasting temperature is 250℃, the roasting time is 60 min, the concentration of hydrochloric acid is 10 mol/L, and the ratio of liquid to solid is 10 (mHCl/ash=10), and 90% Ge in lignite ash can be recovered.

  16. Transformation of chlorine in NaCl-loaded Victorian brown coal during the gasification in steam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu; Mohammad Asadullah; Rosalie Hocking; LIN Jian-ying; LI Chun-zhu

    2012-01-01

    This study is to examine the changes in Cl volatilizations and chemical forms in NaCl-loaded Victorian brown coal during gasification in steam at 800 ℃ using Cl K-edge X-ray absorption near-edge structure (XANES) spectroscopy.The char samples were prepared in a novel one-stage fluidised-bed/fixed-bed quartz reactor at a fast heating rate.The samples were then collected and sealed in an argon-filled bag in order to minimise possible oxidation of char and Cl by air prior to analysis by XANES.Char-steam reactions were found to significantly affect the transformation of Cl,including the possible formation of chlorine-containing organic structures.On the other hand,volatile-char interactions during the gasificauon appeared to enhance the Cl retention and prevent the formation of organic chlorine compounds in chars.

  17. Attacks of Asthma due to Chlorinized Water: Case Report

    Directory of Open Access Journals (Sweden)

    Murat Eyup Berdan

    2008-02-01

    Full Text Available The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been reported. But, attacks of asthma which is related to chlorinized water is rare. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming and a worker can exposed to chlorine while he or she was using water with chlorine at home. We describe a persistent increase in nonspecific bronchial hyperresponsiveness following chronic exposure to strong respiratory irritant with chlorinized water in two subjects with no past history of asthma or atopy. We conclude that airway hyperresponsiveness can develop or increase after chronic inhalation of high concentrations of irritants such as chlorinized water an indoor irritant factor and that these changes may be prolonged. [TAF Prev Med Bull. 2008; 7(1: 87-90

  18. Attacks of Asthma due to Chlorinized Water: Case Report

    Directory of Open Access Journals (Sweden)

    Murat Eyup Berdan

    2008-02-01

    Full Text Available The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been reported. But, attacks of asthma which is related to chlorinized water is rare. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming and a worker can exposed to chlorine while he or she was using water with chlorine at home. We describe a persistent increase in nonspecific bronchial hyperresponsiveness following chronic exposure to strong respiratory irritant with chlorinized water in two subjects with no past history of asthma or atopy. We conclude that airway hyperresponsiveness can develop or increase after chronic inhalation of high concentrations of irritants such as chlorinized water an indoor irritant factor and that these changes may be prolonged. [TAF Prev Med Bull 2008; 7(1.000: 87-90

  19. Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

    Science.gov (United States)

    Ramakrishnan, Sivakumar; Kwok, Teong Chen; Hamid, Sheikh Abdul Rezan Sheikh Abdul

    2016-07-01

    In the present study, chlorination of nitride ilmenite using 2k 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 TiOxCyNz 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.

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

    OpenAIRE

    Buffin, Lisa Webster

    1992-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    冷瑜婷; 杨帆; 吴养洁; 李克

    2011-01-01

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

  2. A Nanoarchitecture Based on Silver and Copper Oxide with an Exceptional Response in the Chlorine-Promoted Epoxidation of Ethylene.

    Science.gov (United States)

    Ramirez, Adrian; Hueso, Jose L; Suarez, Hugo; Mallada, Reyes; Ibarra, Alfonso; Irusta, Silvia; Santamaria, Jesus

    2016-09-01

    The selective oxidation of ethylene to ethylene epoxide is highly challenging as a result of competing reaction pathways leading to the deep oxidation of both ethylene and ethylene oxide. Herein we present a novel catalyst based on silver and copper oxide with an excellent response in the selective oxidation pathway towards ethylene epoxide. The catalyst is composed of different silver nanostructures dispersed on a tubular copper oxide matrix. This type of hybrid nanoarchitecture seems to facilitate the accommodation of chlorine promoters, leading to high yields at low reaction temperatures. The stability after the addition of chlorine promoters implies a substantial improvement over the industrial practice: a single pretreatment step at ambient pressure suffices in contrast with the common practice of continuously feeding organochlorinated precursors during the reaction.

  3. 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...

  4. Blends of caprolactam/caprolactone copolymers and chlorinated polymers

    OpenAIRE

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

    1997-01-01

    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 chlorinated polymers is not compromised until a relatively high lactam content in the copolymer is attained. The incorporation of segmental interaction parameters, derived from separate studies involving pol...

  5. Reactivity of free radical intermediates that form spontaneously during molecular chlorine action on acetylene and vinyl monomers at low temperatures

    International Nuclear Information System (INIS)

    In this study ESR, UV, VIS and IR spectroscopy, chromatography, calorimetry, and elemental analysis were employed to show the spontaneous formation of free radicals under low-temperature action of molecular chlorine on acetylene monomer p-diethynylbenzene, and vinyl monomer acrylamide. These radicals are able to initiate chain reaction of polymerization of monomers at low temperatures. This reaction results in a completely soluble polymer with a yield of 25 %, while an insoluble cross-linked polymer has been obtained during polymerization of p-diethynylbenzene initiated by other means. For example, under radiolysis by 1000 kGy the soluble fraction of obtained polymer was ∼ 1% while the overall yield was ∼ 10%. p-Diethynylbenzene polymerizes at temperatures close to chlorine melting (170 K). Polymerization of acrylamide takes place in the temperature range of 180-210 K with an yield of polymer ∼ 10%. The low-temperature chlorination of a 20%-solution of acrylamide in glycerol enables a twofold increase of the polymer yield, and a tenfold decrease of the chlorine content in it.

  6. 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.

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

    Science.gov (United States)

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

    2014-09-01

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

  8. Scenarios Evaluation Tool for Chlorinated Solvent MNA

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-02-28

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

  9. Fatty acids and algal lipids as precursors of chlorination by-products

    Institute of Scientific and Technical Information of China (English)

    Yan Liang; Yuen Shan Lui; Huachang Hong

    2012-01-01

    Six common algal fatty acids (FAs) with different numbers of double bonds,lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal cells were chlorinated to evaluate their potential in generating disinfection by-products (DBPs).The result showed that the more double bonds in the FAs,the higher the amounts of chloroform and dichloroacetic acid (DCAA) produced,but such a pattern was not observed for trichloroacetic acid (TCAA).Based on the previously reported composition of fatty acids in algal lipids,the DBP generation potentials of algal lipids were calculated.These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction,suggesting unknown lipophilic fraction(s) served as potent DBPs precursors.Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition,given quantified measured DBP production per unit algal lipid and proteins.The analysis showed that the observed DBP production was similar to that predicted (< 35% difference),suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform,DCAA and TCAA formation upon chlorinating algae.

  10. Behavior of Zn and Fe Content in Electric Arc Furnace Dust as Submitted to Chlorination Methods

    Science.gov (United States)

    Santos, Felipe; Brocchi, Eduardo; Araújo, Victor; Souza, Rodrigo

    2015-08-01

    This work covers initially a general thermodynamics assessment regarding the zinc ferrite (ZnFe2O4) behavior toward direct and reducing chlorination. Then, the use of alternative chlorination agents were also theoretically appreciated, before a set of experiments has been carried out with industrial residue (electric arc furnace dust). Besides identifying zinc ferrite (95.4 pct), the XRD analysis indicated the presence of ZnO (4.6 pct). Therefore, the main objective of the present work is related to a theoretical (thermodynamics) and experimental (kinetics) evaluation of the mentioned residue chemical behavior as submitted to chlorination methods. Several characterization methods were used, such as X-ray diffraction, scanning electron microscopy, X-ray fluorescence, mass spectroscopy (ICP-MS), and energy-dispersive X-ray spectroscopy (EDS). It was observed that zinc was present, mostly, in the form of zinc ferrite (franklinite). The thermodynamics study revealed that Zn has a more susceptible behavior regarding the oxides conversion into chlorides. However, this tendency is not necessarily associated with a selective reaction, as showed for the chlorination in the presence of carbon, as both iron and zinc chlorides formation is feasible. The experimental results have indicated that some reaction systems can be further studied in order to identify operational conditions that enable selective formations. So, it was observed that for the calcium chloride reaction conducted at 1273 K (1000 °C) for 30 minutes, the iron content in the residue slightly increases (with 15 pct removal), whereas the zinc content decreases from 20 to 12 pct (53 pct removal), suggesting complementary studies where this possible selectivity could be even more determinant. Such results have also indicated that the direct action of chlorine at 1073 K (800 °C) allowed complete removal of zinc, followed by conversion in the order of 40 pct in iron. Therefore, a complementary investigation over

  11. Study of reactions of metals with sulphur and phosphorus compounds by pulsed temperatures

    International Nuclear Information System (INIS)

    The anti-wear action of sulphur and phosphorus compounds which are usually added to gear-oils depends on chemical reactions with the metallic surfaces of the gears. These reactions occur both at the bulk oil temperature (approx. 100°C) and during high temperatures (approx. 600°C) of short duration when the gearteeth come into contact under lead. The temperature flashes were simulated in an apparatus in which short pulses of electric current were used to heat metal wires immersed in mineral oil containing S35 and P32 labelled compounds in solution. The radioactivity acquired by the wires was measured. The extent of the reactions was determined as a function of temperature and time and the results were interpreted in terms of conventional kinetic laws. The modification of the reaction rates by the presence of other compounds in the solution was studied. The effect of pre-formed surface films containing sulphur phosphorus, chlorine and/or oxygen was also determined. In explaining the results, the structure of the materials used and the diffusion processes whereby the reactions occur beyond the initial stages were considered. (author)

  12. Enhanced bioremediation as a cost effective approach following thermally enhanced soil vapour extraction for sites requiring remediation of chlorinated solvents - 16296

    International Nuclear Information System (INIS)

    Thermally enhanced bioremediation can be a more cost-effective alternative to full scale in-situ thermal treatment especially for sites contaminated with chlorinated solvents, where reductive dechlorination is or might be a dominant biological step. The effect of Thermally Enhanced Soil Vapour Extraction (TESVE) on indigenous microbial communities and the potential for subsequent biological polishing of chlorinated solvents was investigated in field trials at the Western Storage Area (WSA) - RSRL (formerly United Kingdom Atomic Energy Authority - UKAEA) Oxfordshire, UK. The WSA site had been contaminated with various chemicals including mineral oil, chloroform, trichloroethane (TCA), carbon tetrachloride and tetrachloroethene (PCE). The contamination had affected the unsaturated zone, groundwater in the chalk aquifer and was a continuing source of groundwater contamination below the WSA. During TESVE the target treatment zone was heated to above the boiling point of water increasing the degree of volatilization of contaminants of concern (CoC), which were mobilised and extracted in the vapour phase. A significant reduction of concentrations of chlorinated solvent in the unsaturated zone was achieved by the full-scale application of TESVE - In Situ Thermal Desorption (ISTD) technology. The rock mass temperature within target treatment zone remained in the range of 35 deg. - 44 deg. C, 6 months after cessation of heating. The concentration of chlorinated ethenes and other CoC were found to be significantly lower adjacent to the thermal treatment area and 1 to 2 orders of magnitude lower within the thermal treatment zone. Samples were collected within and outside the thermal treatment zone using BioTrapsR (passive, in- situ microbial samplers) from which the numbers of specific bacteria were measured using quantitative polymerase chain reaction (qPCR) methods of analysis. High populations of reductive de-chlorinators such as Dechalococcoides spp. and Dehalobacter spp

  13. 14 CFR 35.35 - Centrifugal load tests.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Centrifugal load tests. 35.35 Section 35.35... STANDARDS: PROPELLERS Tests and Inspections § 35.35 Centrifugal load tests. The applicant must demonstrate... to twice the maximum centrifugal load to which the propeller would be subjected during operation...

  14. Programming NET 35

    CERN Document Server

    Liberty, Jesse

    2009-01-01

    Bestselling author Jesse Liberty and industry expert Alex Horovitz uncover the common threads that unite the .NET 3.5 technologies, so you can benefit from the best practices and architectural patterns baked into the new Microsoft frameworks. The book offers a Grand Tour" of .NET 3.5 that describes how the principal technologies can be used together, with Ajax, to build modern n-tier and service-oriented applications. "

  15. Stable isotope fractionation of chlorine during the precipitation of single chloride minerals

    International Nuclear Information System (INIS)

    Highlights: • Solutions of NaCl, KCl, and MgCl2⋅6H2O were evaporated at 28 ± 2 °C. • The δ37Cl values of samples decreased during precipitation. • Cl isotope has fractionation features different from predecessor research. • New Cl isotopic evolution curve of seawater precipitation were calculated. • The δ37Cl values can be used as an better indicator of brine evolution. - Abstract: In order to better understand chlorine isotopic variations during brine evolution, experiments were designed to determine the changes in the chlorine isotope composition (δ37Cl value) during evaporations of solutions containing NaCl, KCl and MgCl2⋅6H2O at 28 ± 2 °C. Three evaporation experiments were conducted in a clean environment. The precipitate and brine samples were collected during the evaporation, and the chlorine isotopic ratios of the samples were determined using an improved thermal ionisation mass spectrometry procedure based on Cs2Cl+ ion measurement. The results are as follows: the mean fractionation factors of the three solutions are αNa = 1.00055, αK = 1.00025, and αMg = 1.00012, respectively, where αNa, αK and αMg are the fractionation factors between salts (NaCl, KCl and MgCl2⋅6H2O) and saturated solutions. The results showed that the δ37Cl values of precipitate and coexisting brine samples decrease during the precipitation of single chloride minerals. The residual brine was a 35Cl reservoir for different single chloride solutions. New chlorine isotopic evolution curve during seawater evaporation were also calculated. The results indicated that during the primary precipitation stage of halite, δ37Cl decreased continuously, and the most important thing is that this trend continues during the final stages when Mg–salts begin to precipitate

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-04-01

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

  17. 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

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

    Science.gov (United States)

    Tentoni, Stuart C.

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

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

    Science.gov (United States)

    2013-11-06

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

  20. 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...

  1. The effect of torrefaction on the chlorine content and heating value of eight woody biomass samples

    International Nuclear Information System (INIS)

    This study examined and compared the effect of torrefaction on the heating value, elementary composition, and chlorine content of eight woody biomasses. The biomass samples were torrefied in a specially constructed batch reactor at 260 °C for 30, 60, and 90 min. The original biomasses as well as the solid, liquid, and gaseous torrefaction reaction products were analyzed separately. The higher heating values (HHV) of dry samples increased from 19.5–21.0 MJ  kg−1 to 21.2–23.2 MJ  kg−1 during 60 min of torrefaction. In all samples, the HHV increased 9 % on average. Furthermore, the effect of torrefaction time on the biomass HHV was studied. Measurements showed that after a certain point, increasing the torrefaction time had no effect on the samples' HHV. This optimal torrefaction time varied considerably between the samples. For more reactive biomasses, i.e., birch and aspen, the optimal torrefaction time was close 30 min whereas the HHV of less reactive biomasses, e.g., stumps, increased markedly even after a 60-min torrefaction. Another significant observation was that torrefaction reduced the chlorine content of the biomass samples. The chlorine concentration of the solid product dropped in most samples from the original by half or even as much as 90 %. The highest relative chlorine decrease was observed in the Eucalyptus dunnii sample, which also had the highest chlorine content of all the studied biomasses. The relative carbon content of the biomass samples increased during torrefaction as the average elementary composition changed from CH0.123O0.827 to CH0.105O0.674 after a 60-min torrefaction. - Highlights: • Eight woody biomass samples were torrefied at 260 °C. • The chemical and fuel properties of different wood species were analyzed. • Torrefaction reduced the biomass chlorine content. • Torrefaction increased the biomass HHV at maximum by a factor of 1.11. • Torrefaction decreased the biomass elementary O to C-ratio

  2. Biodegradability of Chlorinated Anilines in Waters

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  3. 丙烯酸改性氯化聚丙烯的合成和粘接性能的研究%Study on synthesis and adhesiveness of modified chlorinated polypropylene with acrylic acid

    Institute of Scientific and Technical Information of China (English)

    傅和青; 黄洪; 张心亚; 陈焕钦

    2004-01-01

    氯化聚丙烯是聚丙烯的氯化改性产物,通过改性,其硬度、耐磨性、耐酸性、耐盐水性能比聚丙烯都好,耐热、耐老化性也优于聚丙烯.但其性能尤其是粘接性能还不能满足其在胶粘剂等方面的需要,为了进一步提高氯化聚丙烯的粘接性能,拓宽其应用领城,需对氯化聚丙烯改性.接枝共聚法是一种很好的化学改性方法.本文以丙烯酸(AA)作为接枝单体,以过氧化苯甲酰(BPO)为引发剂,以甲苯为溶剂,采用液相接枝共聚法,将丙烯酸单体接枝到氯化聚丙烯大分子链上,得到丙烯酸改性氯化聚丙烯产物.系统研究了反应温度、反应时间、引发剂过氧化苯甲酰用量和丙烯酸单体用量等因素对丙烯酸接枝改性的氯化聚丙烯产物粘接性能的影响,得出了较佳的工艺条件是反应温度T=100℃,反应时间t=3.5 h,原料质量配比为100份氯化聚丙烯、3份丙烯酸和0.3份的过氧化二苯甲酰.研究还表明,丙烯酸改性的氯化聚丙烯的粘接性能优于氯化聚丙烯的粘接性能.%Grafting of acrylic acid (AA) on chlorinated polypropylene (CPP) by free radical process was carried out at different temperatures and hours using toluene as solvent. The effect of temperature,time,initiator concentration and the ratio of chlorinated polypropylene and acrylic acid on the adhesiveness was studied. The optimum processing conditions were that the reaction temperature was 100 ℃, reaction time was 3.5 h,based on 100 parts chlorinated polypropylene 3 parts of acrylic acid and 0.30 parts benzoyl peroxide (BPO) were used. The adhesiveness of modified chlorinated polypropylene with acrylic acid was better than that of chlorinated polypropylene.

  4. Chlorinated aromatic compounds in a thermal process promoted by oxychlorination of ferric chloride.

    Science.gov (United States)

    Fujimori, Takashi; Takaoka, Masaki; Morisawa, Shinsuke

    2010-03-15

    The relationship between the formation of chlorinated aromatic (aromatic-Cl) compounds and ferric chloride in the solid phase during a thermal process motivated us to study the chemical characteristics of iron in a model solid sample, a mixture of FeCl(3) x 6H(2)O, activated carbon, and boron nitride, with increasing temperature. Fe K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed drastic changes in the chemical form of amorphous iron, consistent with other analytical methods, such as X-ray diffraction using synchrotron radiation (SR-XRD) and Fourier-transform infrared (FT-IR) spectroscopy. Atomic-scale evidence of the chlorination of aromatic carbon was detected by Cl-K X-ray absorption near edge structure (XANES) spectroscopy. These results showed the thermal formation mechanism of aromatic-Cl compounds in the solid phase with ferric chloride. We attribute the formation of aromatic-Cl compounds to the chlorination of carbon, based on the oxychlorination reaction of FeCl(3) at temperatures in excess of ca. 300 degrees C, when the carbon matrix is activated by carbon gasification, catalyzed by Fe(2)O(3), and surface oxygen complexes (SOC) generated by a catalytic cycle of FeCl(2) and FeOCl. Chemical changes of trace iron in a thermal process may offer the potential to generate aromatic-Cl compounds in the solid phase.

  5. Characterization of unknown brominated disinfection byproducts during chlorination using ultrahigh resolution mass spectrometry.

    Science.gov (United States)

    Zhang, Haifeng; Zhang, Yahe; Shi, Quan; Zheng, Hongdie; Yang, Min

    2014-03-18

    Brominated disinfection byproducts (Br-DBPs), formed from the reaction of disinfectant(s) with natural organic matter in the presence of bromide in raw water, are generally more cytotoxic and genotoxic than their chlorinated analogues. To date, only a few Br-DBPs in drinking water have been identified, while a significant portion of Br-DBPs in drinking water is still unknown. In this study, negative ion electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown Br-DBPs in artificial drinking water. In total, 441 formulas for one-bromine-containing products and 37 formulas for two-bromine-containing products, most of which had not been previously reported, were detected in the chlorinated sample. Most Br-DBPs have corresponding chlorine-containing analogues with identical CHO composition. In addition, on-resonance collision-induced dissociation (CID) of single ultrahigh resolved bromine containing mass peaks was performed in the ICR cell to isolate single bromine-containing components in a very complex natural organic matter spectrum and provide structure information. Relatively abundant neutral loss of CO2 was observed in MS-MS spectra, indicating that the unknown Br-DBPs are rich in carboxyl groups. The results demonstrate that the ESI FT-ICR MS method could provide valuable molecular composition and structure information on unknown Br-DBPs.

  6. Observations of chlorine monoxide over Scott Base, Antarctica, during the ozone hole, 1996-2005

    Science.gov (United States)

    Connor, Brian; Solomon, Philip; Barrett, James; Mooney, Thomas; Parrish, Alan

    2007-01-01

    We report observations of chlorine monoxide, ClO, in the lower stratosphere, made from Scott Base (77.85º S, 166.77º E) in springtime during each year, 1996-2005. The ClO amounts in the atmosphere are retrieved from remote measurements of microwave emission spectra. ClO column densities of up to about 2.5 × 1015 cm-2 are recorded during September, when chlorine is present in chemically active forms due to reactions on the surface of Polar Stratospheric Cloud (PSC) particles. Maximum mixing ratios of ClO are approximately 2 ppbv. The annual average of ClO column density during the activation period is anticorrelated with similar averages of ozone column measured at nearby Arrival Heights, with correlation coefficient of –0.81, and with averages of ozone mass integrated over the entire polar region, with similar correlation coefficients. There was a substantial decrease in ClO amounts during 2002-2004. There has been no systematic change in the timing of chlorine deactivation attributable to secular change in the Antarctic vortex

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

    Science.gov (United States)

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

    2015-11-01

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

  8. Removing 3,5-Dichlorophenol from Wastewater by Alternative Adsorbents

    Directory of Open Access Journals (Sweden)

    Kobetičová Hana

    2014-12-01

    Full Text Available The main objective of this paper is to evaluate an efficiency of 3,5 - dichlorophenol removal from wastewater by using alternative adsorbents. Chlorophenols are organic compounds consisting of a benzene ring, OH groups and also atoms of chlorine. Chlorophenols may have a huge isomere variety that means there are differences in their chemical and physical properties. Due to their toxicity it is necessary to remove them from waste water and in this paper an alternative way of such process is described.

  9. Effects of chlorine or chlorine dioxide during immersion chilling on recovery of bacteria from broiler carcasses and chiller water

    Science.gov (United States)

    A study was conducted to determine the microbiological impact of immersion chilling broiler carcasses with chlorine or chlorine dioxide. Eviscerated, pre-chill commercial broiler carcasses were cut into left and right halves along the keel bone, and each half was rinsed (HCR) in 100 mL of 0.1% pept...

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

    Institute of Scientific and Technical Information of China (English)

    WANG Lisha; HU Hongying; WANG Chao; Koichi Fujie

    2007-01-01

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

  11. Colour Reaction of Cadimum with 1-Azobenzene-3-(5-Nitro-2-pyridyl)-Triazene and Its Application%1-偶氮苯基-3-(5-硝基-2-吡啶)-三氮烯与镉的显色反应及其应用

    Institute of Scientific and Technical Information of China (English)

    龚楚儒; 杨明华; 金传明; 陈才元; 胡宗球

    2001-01-01

    @@1 引言 三氮烯试剂是测定IB、ⅡB族金属元素的优良试剂。近年来,对该类试剂中的取代苯重氮氨基苯的合成和分析应用报道较多,但对含杂环的三氮烯试剂的研究报道较少。我们曾将安替比林、苯并噻唑、噻唑引入该类试剂中,使试剂灵敏度有所提高。为进一步探讨此类试剂的分析性能,我们合成了1-偶氮苯基-3-(5-硝基-2-吡啶基)-三氮烯(ABNPDT)。研究其分析性能,结果表明:试剂与镉有灵敏反应,摩尔吸光系数达2.07×105 L·mol-1·cm-1。用拟定方法测定了水样中镉含量,结果令人满意。

  12. Degradation of microcystin-RR in water by chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    JI Ying; HUANG Jun-li; FU Jiao; WU Ming-song; CUI Chong-wei

    2008-01-01

    Due to the potent hepatotoxicity and tumor-promoting activity of microcystins, a successful removal of these toxins during drinking water treatment processes is of increasing concern. The oxidation kinetics of MC-RR by chlorine dioxide (C1O2)was studied with HPLC and characterization of the reacdon products was performed with UV-spectrometry, TOC and LC-MS. Our experimental results show that the oxidation process is a second order overall and a first order with respect to C1O2 and MC-RR.The activation energy of MC-RR degradation by C1O2 is 53.07 kJ/mol. The rate constant k of the action can be increased by increasing temperature and decreasing pH value and ranged from 6. 11x102 L/(mol.min) to 5.29x 102 L/(mol-min) at pH from 3.44 to 10.41 at 10 ℃. Reaction products were determined to be organic and volatile, because they could be almost removed from aqueous solution by heating for 15 min at 60 ℃. In addition, the main oxidation products have m/z values of 1072 and are identified as dihydroxy isomers of MC-RR.

  13. Neutral chlorine and molecular hydrogen at high redshift

    CERN Document Server

    Balashev, S A; Klimenko, V V; Petitjean, P; Srianand, R; Ledoux, C; Ivanchik, A V; Varshalovich, D A

    2015-01-01

    Chlorine and molecular hydrogen are known to be tightly linked together in the cold phase of the local interstellar medium through rapid chemical reactions. We present here the first systematic study of this relation at high redshifts using H$_2$-bearing damped Ly$\\alpha$ systems (DLAs) detected along quasar lines of sight. Using high-resolution spectroscopic data from VLT/UVES and Keck/HIRES, we report the detection of Cl$\\,$I in 9 DLAs (including 5 new detections) out of 18 high-$z$ DLAs with $N($H$_2) \\ge 10^{17.3}\\,$cm$^{-2}$ (including a new H$_2$ detection at $z=3.09145$ towards J$\\,$2100$-$0641) and present upper limits for the remaining 9 systems. We find a $\\sim$5$\\,\\sigma$ correlation between $N$(Cl$\\,$I) and $N$(H$_2$) with only $\\sim$0.2$\\,$dex dispersion over the range 18.1$\\,<\\,$log$\\,N$(H$_2$)$\\,<\\,$20.1, thus probing column densities 10 times lower those seen towards nearby stars, roughly following the relation $N$(Cl$\\,$I$) \\approx 1.5\\times10^{-6} \\times N($H$_2)$. This relation betwee...

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  15. Rapid dechlorination of chlorinated organic compounds by nickel/iron bimetallic system in water

    Institute of Scientific and Technical Information of China (English)

    TONG Shao-ping; WEI Hong; MA Chun-an; LIU Wei-ping

    2005-01-01

    Detoxification of chlorinated organic compounds via reaction with nickel/iron powder was implemented in aqueous solution. Compared to iron, nickel/iron bimetallic powder had higher hydrodechlorination activities for both atrazine (ATR) and p-chlorophenol (pCP); nickel/iron (2.96%, w/w) was shown to have the largest specific surface area and the optimum proportion for the dechlorination of both ATR and pCP. Electrochemical measurements showed that the adsorbed hydrogen atom on the nickel must have been the dominant reductive agent for the dechlorination of both ATR andpCP in this system.

  16. Appraisal of chlorine contact tank modelling practices.

    Science.gov (United States)

    Rauen, William B; Angeloudis, Athanasios; Falconer, Roger A

    2012-11-15

    With new water directives imposing strict regulations to reduce the footprint of treatment operations and contaminant levels, a performance review of water treatment facilities, including Chlorine Contact Tanks (CCTs) is required. This paper includes a critical appraisal of the international literature on CCT modelling practices to date, aiming to assist the identification of areas requiring further development, in particular, relating to the computational modelling capability and availability of tools to assist hydraulic design and optimisation studies of CCTs. It notes that the hydraulic optimisation practice of poorly designed tanks commenced with experimental studies undertaken in the 1960s and 1970s, which involved mainly two types of studies, namely in situ tracer tests and laboratory physical modelling. The former has traditionally been conducted to diagnose the hydraulic performance of existing CCTs, typically based on results such as Residence Time Distribution (RTD) curves and values of the Hydraulic Efficiency Indicators (HEIs). The latter has been useful in trial and error testing of the impact of certain design modifications on those results, with suggestions for later improvements of the field scale unit. In the 1980s mathematical and numerical modelling studies started to be used to assist CCT investigations, offering a greater level of detail in a more cost-effective manner than equivalent experimentally based investigations. With the growth of computing power and the popularisation of computational models, the 1990s saw the development and application of Computational Fluid Dynamics (CFD) tools to simulate the hydraulic performance of CCTs, sometimes independently of experimentation, other than by using available data to calibrate and validate modelling predictions. This has led to the current scenario of CFD models being invaluable assistive tools in optimisation studies of CCTs, with the experimentation practice continuing to allow for specific

  17. Numerical bifurcation diagram for the two-dimensional boundary-fed chlorine-dioxide–iodine–malonic-acid system

    OpenAIRE

    Setayeshgar, S.; Cross, M. C.

    1999-01-01

    We present a numerical solution of the chlorine-dioxide–iodine–malonic-acid reaction-diffusion system in two dimensions in a boundary-fed system using a realistic model. The bifurcation diagram for the transition from nonsymmetry-breaking structures along boundary feed gradients to transverse symmetry-breaking patterns in a single layer is numerically determined. We find this transition to be discontinuous. We make a connection with earlier results and discuss prospects for future work.

  18. 48 CFR 6302.35 - Dismissal without prejudice (Rule 35).

    Science.gov (United States)

    2010-10-01

    ... prejudice (Rule 35). 6302.35 Section 6302.35 Federal Acquisition Regulations System DEPARTMENT OF TRANSPORTATION BOARD OF CONTRACT APPEALS RULES OF PROCEDURE 6302.35 Dismissal without prejudice (Rule 35). When... prejudice to its restoration to the Board's docket when the cause of suspension has been eliminated....

  19. Crossed molecular beam studies of unimolecular reaction dynamics

    International Nuclear Information System (INIS)

    The study of seven radical-molecule reactions using the crossed molecular beam technique with supersonic nozzle beams is reported. Product angular and velocity distributions were obtained and compared with statistical calculations in order to identify dynamical features of the reactions. In the reaction of chlorine and fluorine atoms with vinyl bromide, the product energy distributions are found to deviate from predictions of the statistical model. A similar effect is observed in the reaction of chlorine atoms with 1, 2 and 3-bromopropene. The reaction of oxygen atoms with ICl and CF3I has been used to obtain an improved value of the IO bond energy, 55.0 +- 2.0 kcal mol-1. In all reactions studied, the product energy and angular distributions are found to be coupled, and this is attributed to a kinematic effect of the conservation of angular momentum

  20. Corrosion tests of stainless steels in chlorinated sea water at 45 degrees C. Korrosionsprovning av rostfria staal i klorerat havsvatten vid 45 grader C

    Energy Technology Data Exchange (ETDEWEB)

    Henriksson, S.

    1987-11-01

    To supplement previous corrosion tests of high alloy stainless steels in chlorinated seawater at 35 degrees C three Swedish stainless steels - Avesta 254 SMO, Avesta Monit and Sandvik Sanicro 28 - have been tested at 45 degrees C in North Sea water continously chlorinated with 0.5 and 2.0 ppm chlorine. The most important results can be summarized as follows: - Tubes of the steel 254 SMO, which are seal welded to tube sheets of austenitic stainless steels, are resistant to localized corrosion even at 45 degrees C. - The fully ferritic steel MONIT has to be seal welded to austenitic tube sheets with an overalloyed austenitic filler (Inconel 625 type) in order to avoid corrosion of the welds. - The steel 254 SMO, which was fully resistant to crevice corrosion in simulated flange joints at 35 degrees C, exhibits at 45 degrees C a tendency to superficial crevice attack. - There is no important difference in the galvanic corrosion behaviour of NiAl-bronz (UNC C95500) in contact with the steel 254 SMO at 35 and 45 degrees C. Decreasing the chlorine content from 2.0 to 0.5 ppm, however, reduces the corrosion rate considerably.

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Science.gov (United States)

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

    2015-09-01

    Previous studies show that treatment of cantaloupes with chlorine dioxide (ClO2) gas at 5 mg/liter for 10 min results in a significant reduction (P color, and a 4.6- and 4.3-log reduction of Escherichia coli O157:H7 and Listeria monocytogenes, respectively. However, this treatment could result in the presence of chloroxyanion residues, such as chloride (Cl(-)), chlorite (ClO2(-)), chlorate (ClO3(-)), and perchlorate (ClO4(-)), which, apart from chloride, are a toxicity concern. Radiolabeled chlorine dioxide ((36)ClO2) gas was used to describe the identity and distribution of chloroxyanion residues in or on cantaloupe subsequent to fumigation with ClO2 gas at a mean concentration of 5.1 ± 0.7 mg/liter for 10 min. Each treated cantaloupe was separated into rind, flesh, and mixed (rind and flesh) sections, which were blended and centrifuged to give the corresponding sera fractions. Radioactivity detected, ratio of radioactivity to mass of chlorite in initial ClO2 gas generation reaction, and distribution of chloroxyanions in serum samples were used to calculate residue concentrations in flesh, rind, and mixed samples. Anions detected on the cantaloupe were Cl(-) (∼ 90%) and ClO3(-) (∼ 10%), located primarily in the rind (19.3 ± 8.0 μg of Cl(-)/g of rind and 4.8 ± 2.3 μg of ClO3(-)/g of rind, n = 6). Cantaloupe flesh (∼ 200 g) directly exposed to(36)ClO2 gas treatment showed the presence of only Cl(-) residues (8.1 ± 1.0 μg of Cl(-)/g of flesh, n = 3). Results indicate chloroxyanion residues Cl(-) and ClO3(-) are only present on the rind of whole cantaloupes treated with ClO2 gas. However during cutting, residues may be transferred to the fruit flesh. Because Cl(-) is not toxic, only ClO3(-) would be a toxicity concern, but the levels transferred from rind to flesh are very low. In the case of fruit flesh directly exposed to ClO2 gas, only nontoxic Cl(-) was detected. This indicates that ClO2 gas that comes into contact with edible flesh would not pose a

  3. Chlorination of calcium tungstate by mixture of chlorine and sulfur dioxide

    International Nuclear Information System (INIS)

    Results of thermodynamic calculations and experimental investigations of interaction of calcium tungstate with Cl2+SO2 mixture at 400-850 deg C are presented. It is shown that the processes passes through several sequential and parallel stages with formation of tungsten (6) oxide and calcium chloride as intermediate products. Peculiarities of the process are determined by the ratio of rates of WO3 formation and chlorination stages

  4. Anaerobic Degradation of Chlorinated Hydrocarbons in Groundwater Aquifers or "Chlorinated Hydrocarbon Degradation"

    OpenAIRE

    Nielsen, R. Brent; Jay D Keasling

    1997-01-01

    Groundwater contamination by chlorinated hydrocarbons, such as tetrachloroethene (PCE) or trichloroethene (TCE), is a major concern throughout the United States. A developing strategy for the remediation of PCE and TCE contaminated aquifers is anaerobic biodegradation. From a TCE contaminated groundwater site, microorganisms were enriched with the ability to anaerobically convert PCE and TCE completely to ethene. Kinetic studies performed with this culture showed that degradation of PCE, TCE...

  5. Investigating the Hydrolysis Reactions of a Chemical Warfare Agent Surrogate. A Systematic Study using 1H, 13C, 17O, 19F, 31P, and 35Cl NMR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wilson, Brendan W. [West Virginia Univ., Morgantown, WV (United States)

    2015-07-24

    During the summer of 2015, I participated in the DHS HS-STEM fellowship at Sandia National Laboratories (SNL, NM) under the supervision of Dr. Todd M. Alam in his Nuclear Magnetic Resonance (NMR) Spectroscopy research group. While with the group, my main project involved pursing various hydrolysis reactions with Diethyl Chlorophosphate (DECP), a surrogate for the agent Sarin (GB). Specifically, I performed different hydrolysis reactions, monitored and tracked the different phosphorous containing species using phosphorous (31P) NMR spectroscopy. With the data collected, I performed kinetics studies mapping the rates of DECP hydrolysis. I also used the NMR of different nuclei such as 1H, 13C, 17O, and 35Cl to help understand the complexity of the reactions that take place. Finally, my last task at SNL was to work with Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) NMR Spectroscopy optimizing conditions for 19F- 31P filtering NMR experiments.

  6. Proportion of bromo-DBPs in total DBPs during reclaimed-water chlorination and its related influencing factors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; QU JiuHui; LIU HuiJuan; ZHAO Xu

    2008-01-01

    During the chlorine disinfection of reclaimed-water, the proportion of bromo-disinfection by-products (bromo-DBPs) in total DBPs is affected by chlorine dosage, reaction time, Ph, ammonia nitrogen (NH3-N) and preozonation. Results show that bromo-trihalomethanes (bromo-THMs) form more easily than bromo-haloacetic acids (bromo-HAAs) and bromine incorporation in DBPs decreases with the increase of chlorine dosage. Within 5 h, bromine incorporation in THMs (n(Br)) increases but bromine incorporation in HAAs (n'(Br)) decreases with the extension of reaction time; however, n(Br) decreases and n'(Br) keeps relatively constant at a longer reaction time. Furthermore, bromine incorporation in DBPs is low under acidic and alkaline conditions. The increase of NH3-N concentration inhibits the formation of chloro-DBPs, resulting in the increase of n(Br) and n'(Br) to some extent. Preozonation enhances the formation of HOBr and the increase of bromine incorporation in DBPs; however, ozone of a high concentration oxidizes HOBr to its salt form, leading to the decrease of bromine incorporation in DBPs.

  7. Proportion of bromo-DBPs in total DBPs during reclaimed-water chlorination and its related influencing factors

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    During the chlorine disinfection of reclaimed-water, the proportion of bromo-disinfection by-products (bromo-DBPs) in total DBPs is affected by chlorine dosage, reaction time, pH, ammonia nitrogen (NH3-N) and preozonation. Results show that bromo-trihalomethanes (bromo-THMs) form more easily than bromo-haloacetic acids (bromo-HAAs) and bromine incorporation in DBPs decreases with the increase of chlorine dosage. Within 5 h, bromine incorporation in THMs (n(Br)) increases but bromine incorpo-ration in HAAs (n′(Br)) decreases with the extension of reaction time; however, n(Br) decreases and n′(Br) keeps relatively constant at a longer reaction time. Furthermore, bromine incorporation in DBPs is low under acidic and alkaline conditions. The increase of NH3-N concentration inhibits the formation of chloro-DBPs, resulting in the increase of n(Br) and n′(Br) to some extent. Preozonation enhances the formation of HOBr and the increase of bromine incorporation in DBPs; however, ozone of a high con-centration oxidizes HOBr to its salt form, leading to the decrease of bromine incorporation in DBPs.

  8. Thermal and under irradiation diffusion of chlorine in uranium dioxide

    International Nuclear Information System (INIS)

    This work concerns the study of the thermal and radiation enhanced diffusion of 36Cl in uranium dioxide. We simulated the presence of 36Cl by implanting a quantity of 37Cl comparable to the impurity content of chlorine in UO2. In order to evaluate the diffusion properties of chlorine in the fuel and in particular to assess the influence of the irradiation defects, we performed two kinds of experiments: - the influence of the temperature was studied by carrying out thermal annealings in the temperature range 900 - 1300 C; we showed that implanted chlorine was mobile from temperatures as low as 1000 C and determined a thermal diffusion coefficient D1000 C around 10-16 cm2s-1 - the influence of the irradiation by fission products were studied by irradiating the samples with 127I (energy of 63.5 MeV). We could determine that the diffusion of the implanted chlorine under irradiation and in the range of temperature 30 - 250 C was not purely athermal. We calculated a diffusion coefficient under irradiation D250 C of about 0-14 cm2.s-1. We showed the importance of the implantation and irradiation defects as preferential paths for a fast chlorine transport. We carried out ab initio calculations showing that chlorine is preferentially located in a substitutional site. This is in favour of a Frank-Turnbull diffusion mechanism or a vacancy/chlorine. (author)

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

    Science.gov (United States)

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

    2015-07-01

    Biofouling is the major problem of reverse osmosis (RO) membranes used for desalting seawater (SW). The use of chlorine is a conventional and common practice to control/prevent biofouling. Unlike polyamide RO membranes, cellulose triacetate (CTA) RO membranes display a high chlorine tolerance. Due to this characteristic, CTA membranes are used in most of the RO plants located in the Middle East region where the elevated seawater temperature and water quality promote the risk of membrane biofouling. However, there is no detailed study on the investigation/characterization of CTA-RO membrane fouling. In this investigation, the fouling profile of a full-scale SWRO desalination plant operating with not only continuous chlorination of raw seawater but also intermittent chlorination of CTA-RO membranes was studied. Detailed water quality and membrane fouling analyses were conducted. Profiles of microbiological, inorganic, and organic constituents of analysed fouling layers were extensively discussed. Our results clearly identified biofilm development on these membranes. The incapability of chlorination on preventing biofilm formation on SWRO membranes could be assigned to its failure in effectively reaching throughout the different regions of the permeators. This failure could have occurred due to three main factors: plugging of membrane fibers, chlorine consumption by organics accumulated on the front side fibers, or chlorine adaptation of certain bacterial populations. PMID:25917390

  10. 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.

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  13. Asian Highlands Perspectives 35

    OpenAIRE

    various

    2015-01-01

    This complete version of AHP 35 features four original research articles, three short stories, and seven book reviews. The research articles include studies of camels in Mang ra County, Sinophone Tibetan author Alai, marmot hunting, and the construction and maintenance of yurts.

  14. Asian Highlands Perspectives 35

    Directory of Open Access Journals (Sweden)

    various

    2015-03-01

    Full Text Available This complete version of AHP 35 features four original research articles, three short stories, and seven book reviews. The research articles include studies of camels in Mang ra County, Sinophone Tibetan author Alai, marmot hunting, and the construction and maintenance of yurts.

  15. The NA35 experiment

    CERN Multimedia

    1987-01-01

    The NA35 experiment ran on the Super Proton Synchrotron (SPS) accelerator at CERN. It was used for the study of relativistic nucleus-nucleus collisions which were used to search for evidence of new types of quark matter. Quarks are found inside protons and neutrons, which in turn make up atoms.

  16. Chlorine Dioxide Gas Treatment of Cantaloupe and Residue Analysis

    OpenAIRE

    Kaur, Simran

    2013-01-01

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

  17. Stability and effectiveness of chlorine disinfectants in water distribution systems.

    OpenAIRE

    Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K.

    1986-01-01

    A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic p...

  18. INFRARED VIBRATIONAL SPECTRA OF CHLORINATED AND HYDROGENATED AMORPHOUS SILICON

    OpenAIRE

    Kalem, S; Chevallier, J.; Al Dallal, S.; Bourneix, J.

    1981-01-01

    The infrared spectra of chlorinated and hydrogenated amorphous silicon have been measured. In addition to the hydrogen induced bands at 2110, 1990, 885, 840 and 640 cm-1, we observe two new modes at 545 cm-1 (Si-Cl stretching) and 500 cm-1 ( Si TO modes induced by chlorine). Observation of the 545 cm-1 band proves that chlorine acts as a dangling bond terminator. Upon annealing, some of the Si-Cl groups transform into SiCl4 molecules (SiCl4 stretching at 615 cm-1). A good agreement is found b...

  19. Annex 35: Hybvent

    DEFF Research Database (Denmark)

    Heiselberg, Per

    The Annex 35 research project is aiming at a better knowledge of hybrid systems and focusing on development of control strategies and performance prediction methods for hybrid ventilation in new and retrofitted office buildings. Its main objectives are: • to develop control strategies for hybrid ...... and cost effective hybrid ventilation systems in office and educational buildings......The Annex 35 research project is aiming at a better knowledge of hybrid systems and focusing on development of control strategies and performance prediction methods for hybrid ventilation in new and retrofitted office buildings. Its main objectives are: • to develop control strategies for hybrid...... ventilation systems in new and retrofitted office and educational buildings • to develop methods to predict ventilation performance in hybrid ventilated buildings • . to select suitable measurement techniques for diagnostic purposes to be used in . buildings with hybrid ventilation systems • to promote energy...

  20. ADONET 35 Cookbook

    CERN Document Server

    Hamilton, Bill

    2008-01-01

    The new edition of this Cookbook gives you more than 200 coding solutions and best practices for real problems you're likely to face with this technology using Visual Studio 2008 and the .NET 3.5 platform. Organized to help you find the topic and specific recipe you need quickly and easily, this book also offers clear explanations of how and why each code solution works and warns you of potential pitfalls.

  1. Chlorine treatment effectiveness and physico-chemical and bacteriological characteristics of treated water supplies in distribution networks of Accra-Tema Metropolis, Ghana

    Science.gov (United States)

    Karikari, A. Y.; Ampofo, J. A.

    2013-06-01

    Drinking water quality from two major treatment plants in Ghana; Kpong and Weija Plants, and distribution networks in the Accra-Tema Metropolis were monitored monthly for a year at fifteen different locations. The study determined the relationship between chlorine residual, other physico-chemical qualities of the treated water, and, bacteria regrowth. Results indicated that the treated water at the Kpong and Weija Treatment Plants conformed to WHO guidelines for potable water. However, the water quality deteriorated bacteriologically, from the plants to the delivery points with high numbers of indicator and opportunistic pathogens. This could be due to inadequate disinfection residual, biofilms or accidental point source contamination by broken pipes, installation and repair works. The mean turbidity ranged from 1.6 to 2.4 NTU; pH varied from 6.8 to 7.4; conductivity fluctuated from 71.1 to 293 μS/cm. Chlorine residual ranged from 0.13 to 1.35 mg/l. High residual chlorine was observed at the treatment plants, which decreased further from the plants. Results showed that additional chlorination does not take place at the booster stations. Chlorine showed inverse relationship with microbial counts. Total coliform bacteria ranged from 0 to 248 cfu/100 ml, and faecal coliform values varied from 0 to 128 cfu/100 ml. Other microorganisms observed in the treated water included Aeromonas spp., Clostridium spp. and Pseudomonas spp. Boiling water in the household before consumption will reduce water-related health risks.

  2. Occurrence mode of chlorine in solid products from co-pyrolysis of coal and waste plastic and its emission characteristic during combustion

    Energy Technology Data Exchange (ETDEWEB)

    Li Zheng; Liu Ze-chang; Zhao Ying; Shi Yu-miao [Chemical and Environmental Engineering College of Shandong University of Science and Technology, Qingdao (China)

    2006-12-15

    The occurrence mode of chlorine in solid products from co-pyrolysis of coal and waste plastic was studied by IR and TG-MS. In addition, the emission characteristic of those solid products during combustion was studied. The results indicates that when co-pyrolysis temperature is below 600{sup o}C, there are some organic as well as inorganic chlorine compounds in coke; when the temperature is above 600{sup o}C, there is only inorganic one in the coke. The emission ratio of chlorine is relative to combustion temperature, the co-pyrolysing temperature as well as the percentage of PVC. The emission ratio of chlorine increases with the rising temperature of combustion. When the combustion temperature is 900{sup o}C, the emission ratio is up to 94%. On the contrary, the emission ratio is lower for the solid product from higher co-pyrolysis temperature as the combustion temperature is the same. The highest chlorine emission ratio from pyrolysis at 400{sup o}C is 99.86%, but that from 1000{sup o}C pyrolysis is 94.35%. 7 refs., 7 figs., 1 tab.

  3. 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...

  4. MULTISPECTRAL IDENTIFICATION OF CHLORINE DIOXIDE BYPRODUCTS IN DRINKING WATER

    Science.gov (United States)

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

  5. MICROEMULSION OF MIXED CHLORINATED SOLVENTS USING FOOD GRADE (EDIBLE) SURFACTANTS

    Science.gov (United States)

    Ground water contamination frequently consists of mixed chlorinated solvents [e.g., tetrachloroethylene (PCE), trichloroethylene (TCE), and trans-1,2- dichloroethylene (DCE)]. In this research, mixtures of the food grade (edible) surfactants bis(2-ethylhexyl) sodium sulfosuccinat...

  6. In situ bioremediation of chlorinated solvent with natural gas

    International Nuclear Information System (INIS)

    A bioremediation system for the removal of chlorinated solvents from ground water and sediments is described. The system involves the the in-situ injection of natural gas (as a microbial nutrient) through an innovative configuration of horizontal wells

  7. Effect of Chlorine Dioxide Gas on Polymeric Packaging Materials

    Science.gov (United States)

    Permeability, solubility and diffusion coefficients of chlorine dioxide for high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyvinyl chloride (PVC), polystyrene (PS), polyethylene terephthalate (PET), nylon, and multilayer of ethylene viny...

  8. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

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

  9. 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......-forming elements were torrefied/pyrolyzed in the temperature range of 150-500 degrees C. The relative release of chlorine and sulfur was calculated based on mass balance and analysis of the biomass before and after torrefaction. In selected cases, measurement of methyl chloride (CH3Cl) in the gas from straw...... torrefaction has furthermore been conducted. The release of chlorine from straw was first observed at 250 degrees C and peaked with about 60-70% at 350 degrees C. Analysis of the released gas showed that most of the chlorine was released as methyl chloride. Increasing the straw content in the reactor resulted...

  10. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    Science.gov (United States)

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  14. Kinetics of Chlorine Decay in Water Distribution Systems

    Institute of Scientific and Technical Information of China (English)

    周建华; 薛罡; 赵洪宾; 汪永辉; 郭美芳

    2004-01-01

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

  15. Potential for formation of disinfection by-products from storage of chlorinated surface water in the Basalt aquifer near Fallon, Nevada

    Science.gov (United States)

    Fram, Miranda S.; Maurer, Douglas K.; Lico, Michael S.

    2005-01-01

    Increased pumpage from a basalt aquifer near Fallon, Nevada, has caused its water levels to decline and has induced changes in the quality of water pumped from the basalt. The aquifer is the sole source of water for municipal supply to the city of Fallon, the Naval Air Station Fallon, and the Fallon Paiute-Shoshone Tribe. These changes may be mitigated by storage of surface water in the basalt for subsequent use. Because chlorination of the surface water may be required for storage, the U.S. Geological Survey, in cooperation with the Fallon Paiute-Shoshone Tribe, made laboratory tests using laboratory carbon-organic-free water, surface-water, ground-water, and basaltic-rock samples to determine the potential for formation of disinfection by-products. Experiments with water samples only (no rock and no chlorine) indicated no change in dissolved-organic-carbon (DOC) concentrations over a 20-day reaction period; whereas, all experiments using rock, water, and no chlorine indicated an increase in DOC concentrations. The greatest increase in DOC concentrations for all three water samples occurred in experiments with the rock samples from outcrops on Rattlesnake Hill. Experiments with water only and chlorine yielded a total trihalomethane (THM) concentration of 97.4 ?g/L for the ground-water sample and 347 ?g/L for the surface-water sample. Experiments with mixtures of water, rocks, and chlorine indicated that reactions with the rock consumed chlorine and released significant amounts of organic carbon from the rock, increasing the DOC concentration in the water. The organic carbon in the rocks likely is associated with the secondary clay minerals that line vesicles and fractures in the rocks. THM concentrations were greatest, from 335 to 909 ?g/L, for surface water equilibrated with rock samples from Rattlesnake Hill. However, the concentration of chlorine required to produce these high THM concentrations ranged from 18 to 84 mg/L. The results of the experiments suggest

  16. Mechanisms for formation, chlorination, dechlorination and destruction of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs)

    Energy Technology Data Exchange (ETDEWEB)

    Altarawneh, Mohammednoor; Dlugogorski, Bogdan Z.; Kennedy, Eric M.; Mackie, John C. [Process Safety and Environment Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, NSW 2308 (Australia)

    2009-06-15

    Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) constitute a group of persistent organic pollutants that form almost inexorably in all thermal and combustion operations. This review focuses on mechanisms that govern their formation, chlorination, dechlorination and destruction. As a consequence of their extreme toxicity and propensity to bioaccumulate, PCDD/Fs have been subjected to much scientific research, designed to understand mechanisms and conditions that govern their emission rates and congener distribution (fingerprints). Consensus of opinions in the literature points to heterogeneous pathways contributing substantially more in the total yield of PCDD/Fs in combustion systems than the gas phase pathway. However, in our view, a great complexity of both homogeneous and heterogeneous routes and uncertainties in many thermochemical and rate parameters enable no conclusive statement about the contribution of each route. Chlorination patterns of precursors appear to play a major role in final congener profiles of PCDD/F emissions. According to the most recent theoretical studies, these congener profiles seem consistent with thermodynamic stabilities of dioxins and furans produced in thermal processes, however, further theoretical investigations at more accurate levels are needed to clarify this matter further. Theoretical studies along with experimental findings reveal that the PCDD/PCDF ratio remains very sensitive to the operating conditions, with pyrolytic conditions favouring the formation of PCDFs. A number of reaction mechanisms has been proposed to answer many of the most intriguing questions about the formation of PCDD/Fs. These mechanisms include models of gaseous and heterogeneous reactions, often inferred from theoretical quantum chemical calculations studies, which incorporate steps responsible for formation, chlorination, dechlorination and destruction of dioxins and furans. The review identifies gaps in our present

  17. SCENARIOS EVALUATION TOOL FOR CHLORINATED SOLVENT MNA

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-16

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

  18. Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE

    Energy Technology Data Exchange (ETDEWEB)

    Bloom, Aleisa C [ORNL

    2015-01-01

    Bioremediation of a Large Chlorinated Solvent Plume, Dover AFB, DE Aleisa Bloom, (Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA) Robert Lyon (bob.lyon@aecom.com), Laurie Stenberg, and Holly Brown (AECOM, Germantown, Maryland, USA) ABSTRACT: Past disposal practices at Dover Air Force Base (AFB), Delaware, created a large solvent plume called Area 6 (about 1 mile long, 2,000 feet wide, and 345 acres). The main contaminants are PCE, TCE, and their degradation products. The remedy is in-situ accelerated anaerobic bioremediation (AAB). AAB started in 2006 and is focusing on source areas and downgradient plume cores. Direct-push injections occurred in source areas where contamination is typically between 5 and 20 feet below ground surface. Lower concentration dissolved-phased contamination is present downgradient at 35 and 50 feet below ground surface. Here, permanent injection/extraction wells installed in transects perpendicular to the flow of groundwater are used to apply AAB. The AAB substrate is a mix of sodium lactate, emulsified vegetable oil, and nutrients. After eight years, dissolved contaminant mass within the main 80-acre treatment area has been reduced by over 98 percent. This successful application of AAB has stopped the flux of contaminants to the more distal portions of the plume. While more time is needed for effects to be seen in the distal plume, AAB injections will soon cease, and the remedy will transition to natural attenuation. INTRODUCTION Oak Ridge National Laboratory Environmental Science Division (ORNL) and AECOM (formerly URS Corporation) have successfully implemented in situ accelerated anaerobic bioremediation (AAB) to remediate chlorinated solvent contamination in a large, multi-sourced groundwater plume at Dover Air Force Base (AFB). AAB has resulted in significant reductions of dissolved phase chlorinated solvent concentrations. This plume, called Area 6, was originally over 1 mile in length and over 2,000 feet wide (Figure 1

  19. Disinfection byproduct formation from chlorination of pure bacterial cells and pipeline biofilms.

    Science.gov (United States)

    Wang, Jun-Jian; Liu, Xin; Ng, Tsz Wai; Xiao, Jie-Wen; Chow, Alex T; Wong, Po Keung

    2013-05-15

    Disinfection byproduct (DBP) formation is commonly attributed to the reaction between natural organic matters and disinfectants, yet few have considered the contribution from disinfecting bacterial materials - the essential process of water disinfection. Here, we explored the DBP formation from chlorination and chloramination of Escherichia coli and found that most selected DBPs were detectable, including trihalomethanes, haloacetonitriles, chloral hydrate, chloropicrin, and 1,1,1-trichloro-2-propanone. A positive correlation (P = 0.08-0.09) between DBP formation and the log reduction of E. coli implied that breaking down of bacterial cells released precursors for DBP formation. As Pseudomonas aeruginosa is a dominant bacterial species in pipeline biofilms, the DBP formation potentials (DBPFPs) from its planktonic cells and biofilms were characterized. Planktonic cells formed 7-11 times greater trihalomethanes per carbon of those from biofilms but significantly lower (P disinfection of bacterial planktonic cells in source water and ex situ reaction between biofilms and residual chlorine in pipeline networks as hitherto unknown DBP sources in drinking water.

  20. Researches on Formation of Haloacetic Acids in Chlorination of Drinking Water by a Novel Technique

    Institute of Scientific and Technical Information of China (English)

    LI Xin; REN Yue-ming; QIANG Liang-sheng; ZHAO Hong-bin

    2004-01-01

    Haloacetic acids(HAAs) are formed during the chlorination of drinking water, which are harmful to people′s health due to their carcinogenic and mutagenic effects. In the present study, a detection method combining methyl tert-butyl ether(MtBE) extraction with acid catalysis and gas chromatography coupled with an electron capture detector(GC/ECD) was developed for determining HAAs. The detection limit of this method(MDL) and relative standard deviation(RSD) were below 0.37 μg/L and 6.2%, respectively. The laboratory chlorination experiments were conducted with the purpose of investigating the influences of reaction time, temperature, UV254, bromide and ammonia-nitrogen on the formation of HAAs. The results show that the formation amount of HAAs increases with increasing reaction time and temperature, respectively; and there exists a linear relationship between the formation of HAAs and UV254. The formation amount of HAAs decreases first and then increases as the bromide ion concentration increases, and adding NH+4 is a possible way to control the formation of HAAs.

  1. Survival of Campylobacter jejuni in biofilms after chlorine treatment

    Directory of Open Access Journals (Sweden)

    Kunyaboon, S

    2006-09-01

    Full Text Available Survival of C. jejuni in biofilms isolated from two chicken houses in Thailand (FBRL-C04, FBRLB05 and FBRL-B06 after chlorine treatment was studied. Biofilm cultures were grown on stainless steel surface in 50% trypticase soy broth for 3 days, subsequently C. jejuni cells were allowed to attach to these biofilms for 4 h at 25ºC. Sodium hypochlorite was used to prepare sanitizing solution with active chlorine of 15 ppm and 25 ppm. Stainless steel coupons containing C. jejuni with and without biofilms were treated with chlorine for 30 sec and neutralized with 0.05% sodium thiosulfate. At both concentrations, C. jejuni were inactivated to lower than 1 log10CFU/cm2 when initial attachment load was approximately 4 log10CFU/cm2. However, C. jejuni in all samples treated with 15 ppm active chlorine were recovered in enrichment media. When treated with the higher concentration of chlorine, 25 ppm, C. jejuni in biofilm of FBRL-C04 (5/9, FBRL-B06 (1/9 and biofilm-free surface (1/9 could also be recovered. This indicates that chlorine treatment at 15 and 25 ppm could not completely inactivate C. jejuni attached to biofilms and biofilm-free surfaces. Biofilm of FBRL-C04 enhanced the survival of C. jejuni after chlorine treatment at 25 ppm although biofilm initial attachment as determined by plate count method was similar to that of other biofilms. Attachment load of viable biofilm cells may not contribute to enhanced survival of C. jejuni in chlorine treatment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hartwig, E.O.; Valentine, R.

    1981-09-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.B.

    1980-03-01

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

  4. Challenges in subsurface in situ remediation of chlorinated solvents

    OpenAIRE

    Broholm, Mette Martina; Fjordbøge, Annika Sidelmann; Christiansen, Camilla Maymann; Hønning, J.; B. H. Hansen; Nedergaard, L. W.; Kern, Kristina; Uthuppu, Basil; Jakobsen, Mogens Havsteen; Kjeldsen, Peter; Bjerg, Poul Løgstrup; Ottesen, L.

    2014-01-01

    Chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality at many sites worldwide. In situ remediation of these sites is particularly challenging in heterogeneous fractured media and where the solvents are present as DNAPL. In situ remediation by chemical as well as biological degradation of chlorinated solvents is a contact sport and requires direct contact between the contaminant and the reactants and/or degrading microorganisms. In fractured geologi...

  5. 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.

  6. 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. PMID:26407709

  7. Expression and Identification of Mycoplasma penetrans P35 Lipoprotein

    Institute of Scientific and Technical Information of China (English)

    朱翠明; 吴移谋; 万艳平; 余敏君

    2004-01-01

    Objective: To study the biological activity of Mycoplasma penetrans 35kDa lipoprotein(P35) in vitro, prokaryotic expression vector pQE31/p35 was constructed and recombinant fusion protein P35 (rP35) was expressed in E.coli. Methods: The p35 gene was amplified by polymerase chain reaction(PCR), cloned to pQE31, and a positive clone was screened. PCR-mediated mutagenesis was used to change the two "TGA" triplets to "TGG" triplets within the p35 gene. Production of the recombinant protein was induced by the addition of IPTG to the E.coli culture, rP35 was purified with a Ni-NTA Spin Kit and rP35 purification was analyzed by Western blot. Results: About 1Kb PCR amplification was cloned into pQE31. The two "TGA" triplets within the p35 gene were successfully changed to "TGG" triplets. The pQE31/p35 vector expressed a protein with a calculated molecular mass of 37.4kDa in E.coli. Western blot indicated the 37.4kDa protein was rP35. Conclusion: PQE311p35, a prokaryotic expression vector containing p35 gene, was successfully constructed and expressed in E.coli.

  8. A green Hunsdiecker reaction of cinnamic acids

    Energy Technology Data Exchange (ETDEWEB)

    Sodre, Leonardo R.; Esteves, Pierre M.; Mattos, Marcio C. S. de, E-mail: pesteves@iq.ufrj.br, E-mail: mmattos@iq.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica. Departamento de Quimica

    2013-02-15

    Tribromo- and trichloroisocyanuric acids react with cinnamic acids in NaOH/H{sub 2}O/Et{sub 2}O at room temperature to produce (E)-2-halostyrenes regioselectively in 25-95% yield. Mechanism studies using Hammett correlations and DFT (density functional theory) calculations have shown that this reaction has as rate determining step the electrophilic addition of chlorine atom to the double bond. (author)

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

    Science.gov (United States)

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

    2006-06-01

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

  10. 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.

  11. Effect of wastewater chlorination on endocrine disruptor removal.

    Science.gov (United States)

    Noutsopoulos, C; Mamais, D; Samaras, V; Bouras, T; Marneri, M; Antoniou, K

    2013-01-01

    Endocrine disrupting chemicals (EDCs) are compounds of mainly anthropogenic origin that interfere with the endocrine system of animals and humans thus causing a series of disorders. Wastewater treatment plants are one of the major routes for transporting such chemicals to the water courses. In the context of this study, several chlorination batch tests were performed in order to assess the effectiveness of chlorination to remove bisphenol A (BPA), triclosan (TCS), nonylphenol (NP) and its ethoxylates (NP1EO and NP2EO) from secondary effluent. According to the results, an appreciable removal of NP, BPA and TCS to the order of 60-84% was observed as an effect of moderate chlorination doses. This was not the case for NP1EO and NP2EO as even at high chlorine doses, removal efficiencies were lower (37% for NP1EO and 52% for NP2EO). Removal efficiencies of NP, BPA and TCS are practically independent of contact time, although this was not the case for NP1EO and NP2EO. Based on toxicity experiments, it is anticipated that following chlorination of the target chemicals, production of more toxic metabolites is taking place. Therefore the effectiveness of chlorination to remove EDCs is questionable and more research is needed to guarantee safe wastewater reuse. PMID:23552244

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

    Science.gov (United States)

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

    2006-02-01

    Measurement of chlorine in concrete is very important for studying of corrosion of reinforcing steel in concrete. Corrosion of reinforcing steel is primarily ascribed to the penetration of chloride ions to the steel surface. Preventive measures for avoiding concrete structure reinforcement corrosion requires monitoring the chloride ion concentration in concrete so that its concentration does not exceed a threshold limit to initiate reinforcement concrete corrosion. An accelerator based prompt gamma neutron activation analysis (PGNAA) setup has been developed for non-destructive analysis of elemental composition of concrete samples. The setup has been used to measure chlorine concentration in concrete samples over a 1-3 wt% concentration range. Although a strong interference has been observed between the chlorine gamma-rays and calcium gamma-rays from concrete, the chlorine concentration in concrete samples has been successfully measured using the 1.164 and 7.643 MeV chlorine gamma-rays. The experimental data were compared with the results of the Monte Carlo simulations. An excellent agreement has been achieved between the experimental data and results of Monte Carlo simulations. The study has demonstrated the successful use of the accelerator-based PGNAA setup in non-destructive analysis of chlorine in concrete samples. PMID:16129605

  13. Spatial and temporal variability of inorganic chlorine in Northwestern Europe

    Science.gov (United States)

    Sommariva, R.; Hollis, L. D. J.; Baker, A. R.; Ball, S. M.; Bell, T. G.; Cordell, R. L.; Fleming, Z.; Gaget, M.; Yang, M. X.; Monks, P. S.

    2015-12-01

    Chlorine is well known to be a strong oxidant in the atmosphere;chlorine reactivity impacts the formation of tropospheric ozone, theoxidation of methane and non-methane hydrocarbons, and the cycling ofnitrogen, sulphur and mercury. An accurate assessment of the roleplayed by chlorine in tropospheric chemical processes is complicatedby the scarce knowledge of its sources, sinks and distribution.We report observations of inorganic chlorine species (Cl2, ClNO2,particulate chloride) taken over the period 2014-2015 at threedifferent locations in Britain: an urban site a hundred kilometersfrom the ocean (Leicester), a coastal site mostly affected by shiptraffic (Penlee Point, Cornwall) and a coastal site experiencingeither clean air from the North Sea or polluted air from inland(Weybourne, Norfolk).This dataset provides a first look into the geographical distributionand seasonal variability of chlorine in Northwestern Europe: theresults suggest that, during the night, ClNO2 is ubiquitous withconcentrations in the range of hundreds to thousands of pptV at alllocations, whereas Cl2 can be observed only at coastal sites, withconcentrations of a few tens of pptV. The implications of thewidespread presence of these forms of inorganic chlorine for ozoneproduction and, in general, for the oxidative processes in the loweratmosphere are discussed with the help of a wide range of supportingmeasurements.

  14. 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.

  15. Contribution to chlorine cycle: a Cl stable isotope approach on Mantle-Ocean exchanges

    Science.gov (United States)

    Bonifacie, M.; Jendrzejewski, N.; Pineau, F.; Agrinier, P.

    2003-04-01

    The stable isotope composition of chlorine (37Cl/35Cl) can be used to trace its geochemical cycle and is a powerfull tool to constrain the origin of high chlorine contents found for some fresh MORB glasses. Despite the fact that chlorine is a volatile element of primary importance, its cycle and isotopic fractionation factors during exchange processes between Earth's reservoirs or phases are poorly known. Furthermore, the scarcity of data for solid samples (rocks or minerals) reflects the analytical difficulty to extract chlorine from silicate structure. The classical methods of pyrohydrolysis followed by isotope-ratio mass spectrometric measurements on CH_3Cl gas have been optimised. Our technique represents the most quantitative and precise method of chlorine extraction for δ37Cl determination on solids published to date. Mean extraction yields are 100 ± 3%, δ37Cl values on duplicate extractions show reproducibility better than 0.2 ppm and the blanks represent less than 5% of the sample size. To characterise chlorine behaviour during the oceanic crust alteration, we have analysed fresh MORB glasses (from SWIR and EPR), altered basalts from leg 504B site (EPR), serpentinized peridotites (from SWIR and MAR) and an altered gabbro from the Hess Deep site (EPR). All samples (n=9) are depleted in 37Cl (δ37Cl from -1.4 to 0 ppm) relative to seawater (δ37Cl =0 ppm); Cl concentrations are between 200 and 2200 ppm. Our results on fresh MORBs: δ37Cl = -1.4 ppm and -0.6 ppm are in the lower range already published (-3 to +11 ppm, e.g. Magenheim et al., 95; Stewart, 2000). However, our δ37Cl range of altered samples: δ37Cl = -1.3 to -0.2 ppm (basalts, serpentinised peridotites and gabbro) is outside the range observed by Magenheim et al., 95 (+0.4 to +7.5 ppm in amphibole-rich rocks and smectite veins) despite the fact that in both study amphibole-rich rocks from the same site (i.e. leg 504B) have been analysed. On this site, our δ37Cl results are very homogeneous

  16. Magnetic resonance study of the radiolysis products in chlorinated SrCl2:Fe crystals

    International Nuclear Information System (INIS)

    The main objective of the research presented in this thesis has been to investigate by magnetic resonance techniques and Electron Nuclear Double Resonance (EPR and ENDOR) the atomic structure and properties of the impurity associated paramagnetic point defects produced by X-ray irradiation at low temperature (T=80 K) in chlorinated SrCl2 crystals doped with iron. The original results can be summarized as follows: 1. The tetragonal Fe+ (I) center, produced after X-ray irradiation at liquid nitrogen temperature of chlorinated SrCl2:Fe2+ single crystals and stable up to 700 K, has been studied with X- and Q- band ENDOR. The shf interactions of the unpaired electrons with the Cl nuclei of the first ligand shell and with the central 57Fe nucleus have been identified in the ENDOR spectra. The reconstruction of the X-band EPR spectrum using the ENDOR data showed that all eight Cl ions in the first shell are equivalent. Hence the center has D4h symmetry. Moreover, the ENDOR data strongly suggested that the first shell of Cl ions exhibits a tetragonal compression, confirming the EPR analysis. The simplest structural model which can explain all experimental data consists of an interstitial Fe+ ion with two neighboring substitutional cation impurities, most likely K+, on opposite sites along the tetragonal axis of the center. 2. The tetragonal Fe+ (II) center, produced after X-ray irradiation at liquid nitrogen temperature of chlorinated SrCl2:Fe crystals, which is unstable at RT, has been studied by X- and Q- band ENDOR. Interaction of the unpaired electrons with the Cl nuclei of the first ligand shell and with an impurity lying along the tetragonal axis of the center have been identified and analyzed in the ENDOR spectra. The experimental values of the isotropic and anisotropic shf constants for the first 3''5Cl shell have been used to determine the unpaired spin densities in the 3s and 3p chlorine orbitals as f3s = 0.27% and f3p = 1.95 % respectively, resulting in a total

  17. Efficacy of Nucleic Acid Probes for Detection of Poliovirus in Water Disinfected by Chlorine, Chlorine Dioxide, Ozone, and UV Radiation

    OpenAIRE

    Moore, Norman J.; Margolin, Aaron B.

    1994-01-01

    MilliQ water was inoculated with poliovirus type 1 strain LSc-1 and was treated with disinfectants, including chlorine, chlorine dioxide, ozone, and UV light. No relationship between probes and plaque assays were seen, demonstrating that viral nucleic acids were not destroyed. These findings suggest that nucleic acid probes cannot distinguish between infectious and noninfectious viruses and cannot be used in the evaluation of treated waters.

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

    Science.gov (United States)

    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 population...

  19. Chlorine Stabilizer T-128 enhances efficacy of chlorine against cross contamination by E. coli O157:H7 and Salmonella in fresh-cut lettuce processing

    Science.gov (United States)

    During fresh produce processing, organic materials released from cut tissues can rapidly react with free chlorine in the wash solution, leading to the potential survival of foodborne bacterial pathogens and cross-contamination when the free chlorine is depleted. A reported chlorine stabilizer, T128...

  20. Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1,1-dichloroethylene and chloroform

    Institute of Scientific and Technical Information of China (English)

    Zhimin QIANG; Weiwei BEN; ChinPao HUANG

    2008-01-01

    The degradation of selected chlorinated ali-phatic hydrocarbons (CAHs) exemplified by trichloroethy-lene (TCE), 1,1-dichloroethylene (DCE), and chloroform (CF) was investigated with Fenton oxidation process. The results indicate that the degradation rate was primarily affected by the chemical structures of organic contami-nants. Hydroxyl radicals (·OH) preferred to attack the organic contaminants with an electron-rich structure such as chlorinated alkenes (i.e., TCE and DCE). The dosing mode of Fenton's reagent, particularly of Fe2+, significantly affected the degradation efficiency of studied organic compound. A new "time-squared" kinetic model, C = Coexp(-kobst2), was developed to express the degrada-tion kinetics of selected CAHs. This model was applicable to TCE and DCE, but inapplicable to CF due to their varied reaction rate constants towards ·OH. Chloride release was monitored to examine the degree of dechlorina- tion during the oxidation of selected CAHs. TCE was more easily dechlorinated than DCE and CF. Dichloroacetic acid (DCAA) was identified as the major reaction intermediate in the oxidation of TCE, which could be completely removed as the reaction proceeded. No reaction intermedi- ates or byproducts were identified in the oxidation of DCE and CF. Based on the identified intermediate, the reaction mechanism of TCE with Fenton's reagent was proposed.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    Suhur Saeed

    2015-07-01

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

  3. Recovering Y and Eu from Waste Phosphors Using Chlorination Roasting—Water Leaching Process

    Directory of Open Access Journals (Sweden)

    Mingming Yu

    2016-10-01

    Full Text Available Recovering Y and Eu from waste phosphors using chlorination roasting followed by a water leaching process was investigated in this study. Firstly, by chlorination roasting and water leaching, Y and Eu elements present in waste phosphors were efficiently extracted into a leach solution. Secondly, the majority of the impurities in the solution can be removed by adjusting the pH to 4.5 using a Na2S and NH3·H2O solution. Thirdly, the rare earths can be precipitated afterwards by adding a H2C2O4 solution and adjusting the pH to 2.0. Then rare earth oxides (REOs can be obtained after calcining at 800 °C for 1 h. The characterization study of the waste phosphors and the rare earth oxide products was performed by XRD, XRF, and SEM-EDS analysis to determine the phase and morphological features. Influences of the factors, such as roasting temperatures and time, the addition of ammonium chloride on the roasting of waste phosphors, as well as the pH and the amount of oxalates on the precipitation of Y and Eu, were investigated. The maximum grade (99.84% of mixed rare earth oxides and recovery rate (87.35% of Y and Eu were obtained at the optimized conditions.

  4. The effects of the coke addition and the heating time on the efficiency of chlorination process

    International Nuclear Information System (INIS)

    The preparation of mixed pellet, ZrO2, coke and sucrose, for chlorinating process of ZrO2 pellet has been performed. In this experiments the studied parameters were coke addition and the heating time. The addition of coke was 9.72 grams, 10.5 grams and 11 for the mixture of the 87 grams ZrO2 and 3.5 grams sucrose. The purpose of the coke addition is to from ZrC, which is corresponding to Kroll process with carbon-chlor methos. The weight of cokes had been calculated beyond the stoichiometry. The heating times was held in 10 minutes, 15 minutes, and 20 minutes at the temperature of 100oC that was below the evaporation coke temperature of 315oC. The result show that the efficiency of chlorinating of ZrO2 pellet could be reached of 82.16% with the addition of coke mass of 11 grams at the heating temperature of 100oC with the heating time of 20 minutes

  5. UV spectra and kinetics of radicals produced in the gas phase reactions of Cl, F and OH with toluene

    DEFF Research Database (Denmark)

    Markert, F.; Pagsberg, P.

    1993-01-01

    The gas phase reactions of Cl, F and OH with toluene have been studied by pulse radiolysis combined with time-resolved UV spectroscopy. The formation of benzyl radicals via the abstraction reactions C6H5-CH3 + X --> C6H5-CH2 + HX was observed with X = Cl, F and OH. In the reaction with chlorine...

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

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; GAO Tingyao; ZHOU Rongfeng; MA Lumin

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    崔崇威; 黄君礼; 许晶

    2004-01-01

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

  8. Cold Incineration of Chlorophenols in Aqueous Solution by Advanced Electrochemical Process Electro-Fenton. Effect of Number and Position of Chlorine Atoms on the Degradation Kinetics

    Science.gov (United States)

    Oturan, Nihal; Panizza, Marco; Oturan, Mehmet A.

    2009-09-01

    This study reports the kinetics of the degradation of several chlorophenols (CPs), such as monochlorophenols (2-chlorophenol and 4-chlorophenol), dichlorophenols (2,4-dichlorophenol and 2,6- dichlorophenol), trichlorophenols (2,3,5- trichlorophenol and 2,4,5-trichlorophenol), 2,3,5,6-tetrachlorophenol, and pentachlorophenol, by the electro-Fenton process using a carbon felt cathode and a Pt anode. The effect of number and the position of the chlorine atoms in the aromatic ring on the oxidative degradation rate was evaluated and discussed. The oxidation reaction of all the CPs with hydroxyl radicals evidenced a pseudo-first-order kinetics and the rate constant decreased with increasing the number of chlorine atoms. The absolute rate constant of second-order reaction kinetics between CPs and •OH was determined by the competition kinetics method in the range of (3.56-7.75) × 109 M-1 s-1 and follows the same sequence of the apparent rate constants. The mineralization of several CPs and of a mixture of all CPs under study was monitored by the total organic carbon (TOC) removal and the chlorine release during mineralization was followed by ion chromatography. Our results demonstrated that more chlorinated phenols are more difficult to mineralize; however for all the tested CPs, almost quantitative release of chloride ions was obtained after 6 h of treatment.

  9. Immobilization of chlorine dioxide modified cells for uranium absorption

    International Nuclear Information System (INIS)

    There has been a trend towards the use of microorganisms to recover metals from industrial wastewater, for which various methods have been reported to be used to improve microorganism adsorption characteristics such as absorption capacity, tolerance and reusability. In present study, chlorine dioxide(ClO2), a high-efficiency, low toxicity and environment-benign disinfectant, was first reported to be used for microorganism surface modification. The chlorine dioxide modified cells demonstrated a 10.1% higher uranium adsorption capacity than control ones. FTIR analysis indicated that several cell surface groups are involved in the uranium adsorption and cell surface modification. The modified cells were further immobilized on a carboxymethylcellulose (CMC) matrix to improve their reusability. The cell-immobilized adsorbent could be employed either in a high concentration system to move vast UO22+ ions or in a low concentration system to purify UO22+ 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

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

    Institute of Scientific and Technical Information of China (English)

    HU Chengzhi; LIU Huijuan; QU Jiuhui

    2006-01-01

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

  11. Biofilm formation by Pseudoalteromonas ruthenica and its removal by chlorine.

    Science.gov (United States)

    Saravanan, Periasamy; Nancharaiah, Y Venkata; Venugopalan, Vayalam P; Rao, T Subba; Jayachandran, Seetharaman

    2006-01-01

    The distribution of a recently described marine bacterium, SBT 033 GenBank Accession No. AY723742), Pseudoalteromonas ruthenica, at the seawater intake point, outfall and mixing point of an atomic power plant is described, and its ability to form biofilm was investigated. The effectiveness of the antifouling biocide chlorine in the inactivation of planktonic as well as biofilm cells of P. ruthenica was studied in the laboratory. The results show that the planktonic cells were more readily inactivated than the cells enclosed in a biofilm matrix. Viable counting showed that P. ruthenica cells in biofilms were up to 10 times more resistant to chlorine than those in liquid suspension. Using confocal laser scanning microscopy it was shown that significant detachment of P. ruthenica biofilm developed on a glass substratum could be accomplished by treatment with a dose of 1 mg l-1 chlorine. Chlorine-induced detachment led to a significant reduction in biofilm thickness (up to 69%) and substratum coverage (up to 61%), after 5-min contact time. The results show that P. ruthenica has a remarkable ability to form biofilms but chlorine, a common biocide, can be used to effectively kill and detach these biofilms. PMID:17178570

  12. 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. PMID:27483985

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

    Science.gov (United States)

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

    2016-10-15

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

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2007-02-01

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

  16. Reactions of oxidation of plutonium metal

    International Nuclear Information System (INIS)

    The investigation into preparation of the powdery plutonium oxides under the reaction of metal plutonium with moist (5 % H2O) air and moist (5 % H2O) argon was carried out. The kinetic dependences in the 250 - 400 Deg C range are demonstrated. The vicissitude of the oxidation is shown, the activation energy is calculated for every stage. The mechanism of the metal plutonium oxidation is proposed. The obtained plutonium oxides were shown to have a high reaction ability at 300 - 400 Deg C in the moist air and moist argon media, and to be feasible for the further chemical treatment - dissolving in nitric acid, fluorination and chlorination

  17. 氯化聚丙烯的制备与性能研究%Preparation and performance study of chlorinated polypropylene

    Institute of Scientific and Technical Information of China (English)

    王鉴; 杨琦; 孟庆明; 李志源

    2014-01-01

    本文针对聚丙烯(PP)粘合性差、较难染色、低温呈脆性、收缩率大等缺陷,采用溶液法对聚丙烯进行氯化改性,以AIBN(BPO)为引发剂,氯苯为溶剂,进行自由基引发接枝反应制取氯化聚丙烯(CPP)。通过滴定法得出氯化度的值,并对反应时间、反应温度、引发剂浓度等条件进行考察,得出最优氯化工艺条件,采用红外技术(FT-IR)对CPP加以表征,从溶解性能方面加以分析,进一步阐述了氯化度对其性能的影响。实验结果表明,该法可以得到氯原子的接枝产物,在反应温度120℃,反应时间5h时,CPP的氯化度最高可达52%,氯化度越高溶解度越高。%As polypropylene(PP) adhesive properties is poor, and it is difficult to dye its fibre, what’s more, it is brittle at low temperature, and its shrinkage is large. In order to overcome these disadvantages, pp is modified by chlorination in this paper. Concretion content as follows: we use the AIBN (BPO) as the initiator and the chlorobenzene as the solvent to do the free radical grafting reaction to make up CPP. We obtain the chlorinated degree by titration. By studying the influence of reaction time, reaction temperature on chlorination reaction, we can get the optimal chlorination process conditions. And the CPP are characterized by FT-IR, analyzed from the aspects of dissolving properties, to further understand the impact of chlorinated degree on its performance. The ex-perimental results show that when the reaction temperature is 120℃, and reaction time is 5h, the highest chloride degree can reach 52%. We know that the higher the degree of chlorination is, the higher the solubility could be.

  18. Reductive cleavage of chlorine from 6-chloronicotinic acid on mercury electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Montoya, M., E-mail: mmontoya@uhu.e [Departamento de Ingenieria Quimica, Quimica Fisica y Quimica Organica, Universidad de Huelva, Campus El Carmen, Facultad de Ciencias Experimentales, E-21071 Huelva (Spain); Pintado, S., E-mail: q02pibes@uco.e [Departamento de Quimica Fisica y Termodinamica Aplicada, Universidad de Cordoba, Campus Universitario de Rabanales, edificio ' Marie Curie' ., E-14014 Cordoba (Spain); Rodriguez Mellado, J.M., E-mail: jmrodriguez@uco.e [Departamento de Quimica Fisica y Termodinamica Aplicada, Universidad de Cordoba, Campus Universitario de Rabanales, edificio ' Marie Curie' ., E-14014 Cordoba (Spain)

    2011-04-30

    Highlights: Dissociation constants (as pK) of 6 chloronicotinic acid (6CNA) obtained by UV-vis spectroscopy: -0.80 {+-} 0.05 (-COOH group) and 3.2 {+-} 0.1 (pyridinic nitrogen). Electrolysis of 6CNA evidenced the reductive cleavage of chlorine from the molecule. Kinetic parameters (Tafel slopes and reaction orders) determined at the foot of the waves. Reduction pathways have been proposed. - Abstract: This paper presents polarographic (direct current, dc, and differential pulse, DP) and voltammetric (linear-sweep cyclic voltammetry) studies on the electroreduction of 6-chloronicotinic acid (6CNA) on mercury electrodes. In order to obtain the dissociation constants of 6CNA, UV-vis spectra were recorded as a function of pH. pK values of -0.80 {+-} 0.05 (-COOH group) and 3.2 {+-} 0.1 (pyridinic nitrogen) were obtained. The electrochemical studies were performed in the acidity range 6 M H{sub 2}SO{sub 4} to pH 8. Above the last pH value no signals were obtained. Electrolysis made at potentials corresponding to the limiting current of the first wave indicates that there is a reductive cleavage of chlorine from the molecule. This was confirmed by dc and DP polarografic results and also by voltammetric results. Kinetic parameters such as Tafel slopes and electrochemical reaction orders have been determined at potentials corresponding to the foot of the waves. From these results, together with those obtained by cyclic voltammetry, a reaction pathway is proposed, in which the rate-determining step of the process is the release of a chloride ion from the radical formed after the uptake of a H{sup +} ion and an electron.

  19. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    Directory of Open Access Journals (Sweden)

    M. Mendez

    2013-06-01

    Full Text Available The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  20. Reactions of charged and neutral recoil particles following nuclear transformations. Progress report No. 13

    International Nuclear Information System (INIS)

    Research is reported on: caging and solvent effects in hot 38Cl substitution reactions in chlorinated hydrocarbons (dichlorobenzene), excitation labelling of organic compounds using 80Br, reactions of energetic tritium with graphite and SiC surfaces, and micellar systems and microemulsions studied by positron annihilation

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

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

  2. Degradation of anthracene, pyrene and benzo[a]anthracene in aqueous solution by chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    LIU; Jinquan; HUANG; Junli; SU; Liqiang; CAO; Xiangyu; JI; Ying

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) constitute an important group of micropollutants, which are known to be mutagenic, carcinogenic and/or co-carcinogenic and relatively persistent in the environment. The effects of chlorine dioxide (ClO2) on the degradation of anthracene (ANTH), pyrene (PYR) and benzo[a]anthracene (BaA) in aqueous solution were investigated using high performance liquid chromatography (HPLC). In preliminary experiments, it was observed that ClO2 could remove these three PAHs effectively within a short time. Several factors including reaction time, the concentration of ClO2 and pH of the reaction mixture influencing the degradation ratio of PAHs have been studied by batch experiments. The results showed that the degradation ratio of PAHs was affected by reaction time and the concentration of ClO2 instead of pH. The degradation ratio of ANTH, PYR and BaA could reach their maximum as approximately 99.0%, 67.5% and 89.5%, respectively, under the condition as follows: reaction time 30, 60 and 120 min, the concentration of ClO2 0.1, 0.4 and 0.5 mmol·L-1, and pH 7.2. ANTH was selected as the representative to study the reaction mechanism with ClO2. The oxidation products formed in the reaction of ANTH with ClO2 were tentatively identified by gas chromatography-mass spectrometry (GC-MS), and the results showed that the main product was 9, 10-anthraquinone, which could be biodegraded more easily and quickly than ANTH. Through analyzing the reaction properties of ANTH and ClO2, the possible pathway for the ANTH-ClO2 reaction was proposed based on the theory of single electron transfer (SET).

  3. Synthesis, characterization, and antifungal activity of novel inulin derivatives with chlorinated benzene.

    Science.gov (United States)

    Guo, Zhanyong; Li, Qing; Wang, Gang; Dong, Fang; Zhou, Haoyuan; Zhang, Jing

    2014-01-01

    A group of novel inulin derivatives containing benzene or chlorinated benzene were synthesized by reaction of chloracetyl inulin (CAIL) with the Schiff bases of 4-amino-pyridine, including (2-pyridyl)acetyl inulin chloride (PAIL), 2-[4-(2-chlorobenzylideneamino)-pyridyl]acetyl inulin chloride (2CPAIL), 2-[4-(4-chlorobenzylideneamino)-pyridyl]acetyl inulin chloride (4CPAIL), and 2-[4-(2,4-dichlorobenzylideneamino)-pyridyl]acetyl inulin chloride (2,4DCPAIL). Their antifungal activity against three kinds of phytopathogens was estimated by hypha measurement in vitro. Of all the synthesized chitosan derivatives, 2,4DCPAIL inhibited the growth of the tested phytopathogens with inhibitory indices of 67%, 47%, and 43% against Colletotrichum lagenarium (Pass) Ell.et halst, Phomopsis asparagi (Sacc.) Bubak and Fusarium oxysporum (schl.) F.sp. niveum (F. oxysporum) respectively at 1.0 mg/mL. The results indicate that all the inulin derivatives have better antifungal activity than inulin, and the inhibitory index is affected by the chlorine atom grafted to the inulin derivatives.

  4. Oxidation of diclofenac by aqueous chlorine dioxide: identification of major disinfection byproducts and toxicity evaluation.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai

    2014-03-01

    Diclofenac (DCF), a synthetic non-steroidal anti-inflammatory drug, is one of the most frequently detected pharmaceuticals in the aquatic environment. In this work, the mechanism and toxicity of DCF degradation by ClO2 under simulated water disinfection conditions were investigated. Experimental results indicate that rapid and significant oxidation of DCF occurred within the first few minutes; however, its mineralization process was longer than its degradation process. UPLC-MS and (1)H NMR spectroscopy were performed to identify major disinfection byproducts that were generated in three tentative degradation routes. The two main routes were based on initial decarboxylation of DCF on the aliphatic chain and hydroxylation of the phenylacetic acid moiety at the C-4 position. Subsequently, the formed aldehyde intermediates were the starting point for further multistep degradation involving decarboxylation, hydroxylation, and oxidation reactions of CN bond cleavage. The third route was based on transient preservation of chlorinated derivatives resulting from electrophilic attack by chlorine on the aromatic ring, which similarly underwent CN bond cleavage. Microtox bioassay was employed to evaluate the cytotoxicity of solutions treated by ClO2. The formation of more toxic mid-byproducts during the ClO2 disinfection process poses a potential risk to consumers.

  5. Correlation between SUVA and DBP formation during chlorination and chloramination of NOM fractions from different sources.

    Science.gov (United States)

    Hua, Guanghui; Reckhow, David A; Abusallout, Ibrahim

    2015-07-01

    Natural organic matter (NOM) is the major precursor to the formation of disinfection byproducts (DBPs) during drinking water treatment. Specific ultraviolet absorbance (SUVA) is a widely used surrogate parameter to characterize NOM and predict its DBP formation potential. The objective of this study was to determine the relationships between SUVA and different classes of DBPs formed by NOM fractions from different sources. Three natural waters with a wide SUVA range were fractionated into differing hydrophobicity and molecular weight groups using XAD-4 and XAD-8 resins and ultrafiltration membranes. Each NOM fraction was treated with chlorine and monochloramine under controlled laboratory conditions. Different classes of DBPs showed different relationships with SUVA. SUVA correlated strongly with trihaloacetic acids (THAAs) and unknown total organic halogen (UTOX) yields whereas weak correlations were observed between SUVA and trihalomethane (THM) and dihaloacetic acid (DHAA) yields during chlorination. These results reinforce the hypothesis that DHAAs and THAAs form through different precursors and reaction pathways. Strong correlation between SUVA and UTOX was also observed during chloramination. However, no significant relationship was observed between SUVA and chloramination THMs and DHAAs. Overall, SUVA is a good indicator for the formation of unknown DBPs. This indicates that UV absorbing compounds and aromatic carbon within NOM are the primary sources of precursors for unknown DBPs.

  6. 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.

  7. Papillomas on fish exposed to chlorinated wastewater effluent.

    Science.gov (United States)

    Grizzle, J M; Melius, P; Strength, D R

    1984-11-01

    The presence of carcinogenic and mutagenic chemical(s) in the effluent of a wastewater treatment plant was indicated by papillomas developing on caged black bullheads (Ictalurus melas), hepatic enzyme induction in exposed fish, and Ames test mutagenicity of organic extracts of the wastewater. Although virus-like particles have been reported in papillomas of several other fish species, no evidence was obtained for the presence of viruses in the black bullhead papillomas. Mutagenic and carcinogenic chemicals were not identified in the wastewater, but chlorination was implicated as a factor contributing to the induction of the papillomas. The prevalence of papillomas on wild black bullheads exposed to the effluent decreased from 73 to 23% after the amount of residual chlorine (CAS: 7782-50-5) in the effluent leaving the chlorine contact chamber was reduced from 1.3-3.1 mg/liter to 0.25-1.2 mg/liter. PMID:6593489

  8. Electronic diffraction study of the chlorination of nickel

    International Nuclear Information System (INIS)

    A study has been made of the chlorination of the (100), (110) and (111) crystal faces of nickel using high energy electron diffraction and electron microscopy. Two methods have been used: bombardment with chlorine ions having an energy of between 10 and 30 keV, and direct chlorination in a diffractor at pressures of about 10-4 torr. It has thus been possible to show the very special properties of nickel chloride (CdBr2 type, space group R 3-bar m) which is always formed along the (0001) plane, whatever the orientation of the substrate. It has also been possible to attain the metal-halide interface and to show the existence of two-dimensional chemisorbed films which are ordered or disordered according to the crystal orientation. (author)

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

    Directory of Open Access Journals (Sweden)

    Iwona Pełech

    2013-01-01

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

  10. Experimental study on cryptosporidium inactivation in drinking water by chlorine-based disinfectants%氯系消毒剂杀灭饮用水中隐孢子虫试验研究

    Institute of Scientific and Technical Information of China (English)

    刘丽娜; 张鑫; 崔崇威; 孙兴滨

    2013-01-01

    为了考察氯系消毒剂对饮用水中隐孢子虫的灭活作用,分别对氯气和二氧化氯的投加量、反应时间、浊度、pH值和温度等影响因素进行考察.实验结果表明,氯系消毒剂对隐孢子虫理想灭活效果的反应条件是氯气投量6.5 mg/L,反应360 min,ClO2投量3.0 mg/L,反应120 min;浊度越高,氯气对隐孢子虫的灭活率越低,ClO2对隐孢子虫灭活率当浊度升高到5.0和10.0 ntu时,影响基本稳定;pH值波动对氯气灭活影响不大,ClO2在pH值6~7范围内灭活效果最佳;5~35℃范围,水温增加,灭活效果逐渐增强.%In order to find chlorine-based disinfectants' inactivation effect on cryptosporidium in drinking water,factors influencing inactivation efficiency such as the dosage of chlorine and chlorine dioxide,contact time,turbidity,pH value and temperature were investigated.It was found that optimal cryptosporidim inactivation efficacy of chlorine-based disinfectants was obtained at 360 min with chlorine dosage of 6.5 mg/L and at 120 min with chlorine dioxide dosage of 3.0 mg/L,respectively.Cryptosporidium inactivation ratio of chlorine reduced with higher turbidity; cryptosporidium inactivation ratio of chlorine dioxide was almost stable when turbidity increased to 5.0 and 10.0 ntu.The fluctuating of pH value had little influence on inactivation by chlorine; optimal inactivation efficiency of chlorine dioxide was obtained at pH value of 6 ~ 7.In the temperature range of 5 ~ 35 ℃,inactivation ratio was enhanced with the increase of water temperature.

  11. 76 FR 62149 - American Chemistry Council, The Chlorine Institute, Inc., the Fertilizer Institute, and PPG...

    Science.gov (United States)

    2011-10-06

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

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

    Institute of Scientific and Technical Information of China (English)

    Yu Li; Changcong Cui

    2005-01-01

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

  13. Project Summary. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    Science.gov (United States)

    This project evaluated the potential of an innovative approach to aquifer restoration: enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (...

  14. The Health Effects of Chlorine Dioxide as a Disinfectant in Potable Water: A Literature Survey

    Science.gov (United States)

    Calabrese, Edward J.; And Others

    1978-01-01

    The use of chlorine dioxide as a disinfectant in water is being considered by the EPA. This article presents a summary of the known published reports concerning health effects of chlorine dioxide on animal and human populations. (Author/MA)

  15. 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)

  16. Thermodynamic equilibrium diagram of the chlorine-titanium system

    Institute of Scientific and Technical Information of China (English)

    DU Ailing; GUO Xiaofei; ZHANG Heming; LIU Jiang

    2005-01-01

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

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

    OpenAIRE

    Chen, Y.S.(China Institute of Atomic Energy, P.O. Box 275 (10), Beijing 102413, PR China); Vaughn, J M

    1990-01-01

    The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4 degrees C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10(5)-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa a...

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

    Directory of Open Access Journals (Sweden)

    Olivier Louisnard

    2010-02-01

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

  19. 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

  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...... the potential for development of degradation throughout the entire clay matrix. When ERD is applied in a low permeability settings one of the major constraints is to obtain the necessary contact between electron donor, bacteria and contaminants to achieve reasonable remediation timeframes. Two injection methods...

  1. Inorganic Chlorine Partitioning in the Summer Lower Stratosphere: Modeled and Measured [ClONO2/HCl] During POLARIS

    Science.gov (United States)

    Voss, P. B.; Stimpfle, R. M.; Cohen, R. C.; Hanisco, T. F.; Bonne, G. P.; Perkins, K. K.; Lanzendorf, E. J.; Anderson, J. G.; Salawitch, R. J.

    2001-01-01

    We examine inorganic chlorine (Cly) partitioning in the summer lower stratosphere using in situ ER-2 aircraft observations made during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) campaign. New steady state and numerical models estimate [ClONO2]/[HCl] using currently accepted photochemistry. These models are tightly constrained by observations with OH (parameterized as a function of solar zenith angle) substituting for modeled HO2 chemistry. We find that inorganic chlorine photochemistry alone overestimates observed [ClONO2]/[HCl] by approximately 55-60% at mid and high latitudes. On the basis of POLARIS studies of the inorganic chlorine budget, [ClO]/[ClONO2], and an intercomparison with balloon observations, the most direct explanation for the model-measurement discrepancy in Cly partitioning is an error in the reactions, rate constants, and measured species concentrations linking HCl and ClO (simulated [ClO]/[HCl] too high) in combination with a possible systematic error in the ER-2 ClONO2 measurement (too low). The high precision of our simulation (+/-15% 1-sigma for [ClONO2]/[HCl], which is compared with observations) increases confidence in the observations, photolysis calculations, and laboratory rate constants. These results, along with other findings, should lead to improvements in both the accuracy and precision of stratospheric photochemical models.

  2. Identification and characterization of phenylacetonitrile as a nitrogenous disinfection byproduct derived from chlorination of phenylalanine in drinking water.

    Science.gov (United States)

    Ma, Xiaoyan; Deng, Jing; Feng, Jiao; Shanaiah, Narasimhamurthy; Smiley, Elizabeth; Dietrich, Andrea M

    2016-10-01

    Unregulated disinfection byproducts (DBPs), including nitrogenous disinfection byproducts (N-DBPs), originating from chlorination of the precursor amino acid phenylalanine in aqueous systems, were identified in laboratory reactions and distributed tap. The major N-DBP identified was phenylacetonitrile, and minor DBPs of benzyl chloride, phenylacetaldehyde, 2-chlorobenzyl cyanide, and 2, 6-diphenylpyridine were also formed. Phenylacetonitrile was generated through decarboxylation, dechlorination and/or hydrolysis processes. With an aromatic structure, phenylacetonitrile has an unpleasant odor of various descriptors and an odor threshold concentration of 0.2 ppt-v as measured through gas chromatography-olfactometry. The half-life of phenylacetonitrile in reagent water and chlorinated water at 19 °C were 121 h and 792 h, respectively. The occurrence of phenylacetonitrile as an N-DBP in tap water was investigated for the first time; the results revealed that μg/L concentrations were present in nine different distributed drinking waters in China and the United States. Phenylacetonitrile deteriorates the aesthetic quality of drinking water and may present risk due to its prolonged existence in drinking water, especially in the presence of residual chlorine.

  3. Hydrogeological modeling constraints provided by geophysical and geochemical mapping of a chlorinated ethenes plume in northern France

    Science.gov (United States)

    Razafindratsima, Stephen; Guérin, Roger; Bendjoudi, Hocine; de Marsily, Ghislain

    2014-09-01

    A methodological approach is described which combines geophysical and geochemical data to delineate the extent of a chlorinated ethenes plume in northern France; the methodology was used to calibrate a hydrogeological model of the contaminants' migration and degradation. The existence of strong reducing conditions in some parts of the aquifer is first determined by measuring in situ the redox potential and dissolved oxygen, dissolved ferrous iron and chloride concentrations. Electrical resistivity imaging and electromagnetic mapping, using the Slingram method, are then used to determine the shape of the pollutant plume. A decreasing empirical exponential relation between measured chloride concentrations in the water and aquifer electrical resistivity is observed; the resistivity formation factor calculated at a few points also shows a major contribution of chloride concentration in the resistivity of the saturated porous medium. MODFLOW software and MT3D99 first-order parent-daughter chain reaction and the RT3D aerobic-anaerobic model for tetrachloroethene (PCE)/trichloroethene (TCE) dechlorination are finally used for a first attempt at modeling the degradation of the chlorinated ethenes. After calibration, the distribution of the chlorinated ethenes and their degradation products simulated with the model approximately reflects the mean measured values in the observation wells, confirming the data-derived image of the plume.

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

    OpenAIRE

    Walker, M.; Newman, J.

    2010-01-01

    Shock chlorination is used for rapid disinfection to control pathogens and nuisance bacteria in domestic wells. A typical shock chlorination procedure involves adding sodium hypochlorite in liquid bleach solutions to achieve concentrations of free chlorine of up to 200 ppm in the standing water of a well. The change in pH and oxidation potential may bring trace metals from aquifer materials into solution and chlorine may react with dissolved organic carbon to form disinfection byproducts. We ...

  5. Chlorine Dioxide Inactivation of Cryptosporidium parvum Oocysts and Bacterial Spore Indicators

    OpenAIRE

    Chauret, Christian P.; Radziminski, Chris Z.; Lepuil, Michael; Creason, Robin; Andrews, Robert C.

    2001-01-01

    Cryptosporidium parvum, which is resistant to chlorine concentrations typically used in water treatment, is recognized as a significant waterborne pathogen. Recent studies have demonstrated that chlorine dioxide is a more efficient disinfectant than free chlorine against Cryptosporidium oocysts. It is not known, however, if oocysts from different suppliers are equally sensitive to chlorine dioxide. This study used both a most-probable-number–cell culture infectivity assay and in vitro excysta...

  6. Study on encapsulation of chlorine dioxide in gelatin microsphere for reducing release rate

    OpenAIRE

    Ci, Ying; Wang, Lin; Guo, YanChuan; Sun, Ruixue; Wang, Xijie; Li, Jinyou

    2015-01-01

    Objective: This study aims to explore the effects of encapsulation of chlorine dioxide in a hydrophilic biodegradable polymer gelatin to reduce its release rate. Methods: An emulsification-coacervation method was adopted. The characterizations of chlorine dioxide-gelatin microspheres were described. Using UV-vis spectrophotometer the λmax of chlorine dioxide was observed at 358 nm. The particle size and distribution of chlorine oxide-gelatin microspheres was measured by a dynamic light scatte...

  7. Removal of iodide from water by chlorination and subsequent adsorption on powdered activated carbon

    OpenAIRE

    Ikari, Mariya; Matsui, Yoshihiko; Suzuki, Yuta; Matsushita, Taku; Shirasaki, Nobutaka

    2015-01-01

    Chlorine oxidation followed by treatment with activated carbon was studied as a possible method for removing radioactive iodine from water. Chlorination time, chlorine dose, the presence of natural organic matter (NOM), the presence of bromide ion (Br-), and carbon particle size strongly affected iodine removal. Treatment with superfine powdered activated carbon (SPAC) after 10-min oxidation with chlorine (1 mg-Cl-2/L) removed 90% of the iodine in NOM-containing water (dissolved organic carbo...

  8. Combustion Characteristics of Chlorine-Free Solid Fuel Produced from Municipal Solid Waste by Hydrothermal Processing

    OpenAIRE

    Kunio Yoshikawa; Pandji Prawisudha; Bayu Indrawan

    2012-01-01

    An experimental study on converting municipal solid waste (MSW) into chlorine-free solid fuel using a combination of hydrothermal processing and water-washing has been performed. After the product was extracted from the reactor, water-washing experiments were then conducted to obtain chlorine-free products with less than 3000 ppm total chlorine content. A series of combustion experiments were then performed for the products before and after the washing process to determine the chlorine conten...

  9. Chemical aspects of incinerating highly chlorinated and actinide α contaminated organic waste: application to the Iris process

    International Nuclear Information System (INIS)

    general. The fly-ash composition includes over 50 wt% chlorine, as shown in Table III. Thermodynamic analysis showed that phosphorus could be substituted in situ for chlorine by adding a phosphate compound to the feed stream, such as tributylphosphate, which decomposes on heating to produce phosphoric anhydride (P2O5). All the following reversible reactions have very negative free enthalpy at 500 K and 1500 K: 3ZnCl2(g) + P2O5 (g) + 3H2O (g) ↔ Zn3(PO4)2 (c) + 6HCl (g) (4) and 3ZnCl2(g) + P2O5 (g) + 3/2O2 (g) ↔ Zn3(PO4)2 (c) + 3Cl2 (g) (5). Predictably, adding phosphorus to the feed stream significantly shifts the above equilibria to the right at both test temperatures. This behavior was confirmed by a series of tests. The average bottom ash and fly-ash compositions recovered after incineration of these waste mixtures are listed in Table V. Note that the fly-ash contained virtually no chlorine (the concentration diminished from 51.4 to 0.2 wt%). Bottom ash consisted mainly of silica and alumina, and was therefore suitable for vitrification. Practically all the plutonium remained in the bottom ash; the fraction entrained into the after-burner and reaching the filter stages, representing about 1 %, depended entirely on the gas flow conditions of the process. The investigations and tests conducted here partially identified the mechanisms involved at each step of the heat treatment process. The mechanisms are shown schematically for pyrolysis with a phosphorus additive, which leads to the formation of a zinc phosphate in the after-burner through a gas-gas reaction mechanism. As to future upgrading, it is necessary to consider that the phosphate, unlike zinc chloride, is a liquid at the after-burner temperature. (authors)

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  11. Effectiveness of chlorine, organic acids and UV treatments in reducing Escherichia coli O157:H7 and Yersinia enterocolitica on apples.

    Science.gov (United States)

    Escudero, M E; Velázquez, L; Favier, G; de Guzmán, A M

    2003-06-01

    This study assessed the effectiveness of 200 and 500 ppm of chlorine and organic acids (0.5% lactic acid and 0.5% citric acid) in wash solutions, and UV radiation for reducing Escherichia coli O157:H7 and Yersinia enterocolitica on apples contaminated by two different methods. Residual levels of these pathogens after different treatments were compared. On dip inoculated apples, Y. enterocolitica reductions of 2.66 and 2.77 logs were obtained with 200 and 500 ppm chlorine combined with 0.5% lactic acid, respectively. The E. coli O157:H7 population decreased 3.35 log with 0.5% lactic acid wash solution, and 2.72 and 2.62 logs after 500 ppm chlorine and 500 ppm chlorine plus 0.5% lactic acid treatments, respectively. Similar reductions were obtained with UV radiation. On spot inoculated apples, significant (p lactic acid treatment as compared with the control. In sectioned apples, microorganisms infiltrated in inner core region and pulp were not significantly (p lactic acid solution were very proximal to the 5-log score required by FDA for apple disinfection. PMID:12884547

  12. [Formation of disinfection by-products by Microcystis aeruginosa intracellular organic matter: comparison between chlorination and bromination].

    Science.gov (United States)

    Tian, Chuan; Guo, Ting-Ting; Liu, Rui-Ping; Jefferson, William; Liu, Hui-Juan; Qu, Jiu-Hui

    2013-11-01

    In order to illustrate the effects of released algal organic matter in cyanobacteria blooms on raw water quality and water treatment process, intracellular organic matter (IOM) of Microcystis aeruginosa, which is the dominant species in cyanobacteria blooms, was chosen as a precursor and characterized. In addition, the transformation of IOM and the formation of disinfection byproducts were evaluated at different pH of 6.5, 7.1 and 8.4 after chlorination or bromination, with subsequent correlation analysis. The results indicated that IOM was primarily composed of macromolecular matter, i. e. , the species with relative molecular weight of > 30 x 10(3), constituting 68.8% of dissolved organic carbon (DOC). Fluorescence excitation-emission matrix indicated that IOM was mainly composed of aromatic protein-like matter with an intensity of 92.6 AU x L x mg(-1). After reaction with chlorine or bromine, the intensity of aromatic protein-like peaks decreased sharply by 76.6% - 93.3%, and its reduction correlated well with the formation of trihalomethane (THMs, R2 = 0.81) and haloacetic acid (HAAs, R2 = 0.77). The formation of THMs and HAAs increased with the increase in pH. Compared with chlorine, bromine formed more THMs and HAAs, and tended to form highly halogenated HAAs. However, with increasing pH, the reactivity with IOM between chlorine and bromine was closer, i.e, k(OBr-IOM)/k(OCl-(IOM) < k(HOBr-IOM/k(HOCl-IOM).

  13. Chlorine-36 and the initial value problem

    Science.gov (United States)

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

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

  14. Development and Electrochemical Studies of Ruthenium Based Mixed Oxide Catalyst Electrodes for Chlorine Evolution

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Experimental results are presented which allow comparison of the electrochemical performance of RuO2/Ti, Ru0.3Sn0.7O2/Ti and Ru0.3V0.7O2/Ti catalysts prepared on a titanium substrate by thermal decomposition from respective precursors. The highest activity for chlorine evolution is observed on the Ru0.3V0.7O2/Ti electrode, lower on Ru0.3Sn0.7O2/Ti and least on RuO2/Ti. Voltammograms obtained in the polarisable region are used to characterize the different electrodes. Further more an analysis of the catalytic activity and reaction kinetics of the developed electrodes in NaCl are presented.

  15. I + (H2O)2 → HI + (H2O)OH Forward and Reverse Reactions. CCSD(T) Studies Including Spin-Orbit Coupling.

    Science.gov (United States)

    Wang, Hui; Li, Guoliang; Li, Qian-Shu; Xie, Yaoming; Schaefer, Henry F

    2016-03-01

    The potential energy profile for the atomic iodine plus water dimer reaction I + (H2O)2 → HI + (H2O)OH has been explored using the "Gold Standard" CCSD(T) method with quadruple-ζ correlation-consistent basis sets. The corresponding information for the reverse reaction HI + (H2O)OH → I + (H2O)2 is also derived. Both zero-point vibrational energies (ZPVEs) and spin-orbit (SO) coupling are considered, and these notably alter the classical energetics. On the basis of the CCSD(T)/cc-pVQZ-PP results, including ZPVE and SO coupling, the forward reaction is found to be endothermic by 47.4 kcal/mol, implying a significant exothermicity for the reverse reaction. The entrance complex I···(H2O)2 is bound by 1.8 kcal/mol, and this dissociation energy is significantly affected by SO coupling. The reaction barrier lies 45.1 kcal/mol higher than the reactants. The exit complex HI···(H2O)OH is bound by 3.0 kcal/mol relative to the asymptotic limit. At every level of theory, the reverse reaction HI + (H2O)OH → I + (H2O)2 proceeds without a barrier. Compared with the analogous water monomer reaction I + H2O → HI + OH, the additional water molecule reduces the relative energies of the entrance stationary point, transition state, and exit complex by 3-5 kcal/mol. The I + (H2O)2 reaction is related to the valence isoelectronic bromine and chlorine reactions but is distinctly different from the F + (H2O)2 system.

  16. Effect of sulfur dioxide on indium(3) sulfate chlorination

    International Nuclear Information System (INIS)

    The results of thermodynamic calculations and kinetic investigations of In2(SO4)3 interaction with gaseous Cl2 and equimolar Cl2 and SO2 mixture at 127-800 deg C are presented. It is found that acceleration of chlorination rate takes place in the presence of SO2, while the temperature of its beginning and activation energy decrease

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

    Science.gov (United States)

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

    2015-01-01

    The possible approaches for in situ aerobic cometabolism of aquifers and vadose zones contaminated by chlorinated solvents are critically evaluated. Bioaugmentation of resting-cells previously grown in a fermenter and in-well addition of oxygen and growth substrate appear to be the most promising approaches for aquifer bioremediation. Other solutions involving the sparging of air lead to satisfactory pollutant removals, but must be integrated by the extraction and subsequent treatment of vapors to avoid the dispersion of volatile chlorinated solvents in the atmosphere. Cometabolic bioventing is the only possible approach for the aerobic cometabolic bioremediation of the vadose zone. The examined studies indicate that in situ aerobic cometabolism leads to the biodegradation of a wide range of chlorinated solvents within remediation times that vary between 1 and 17 months. Numerous studies include a simulation of the experimental field data. The modeling of the process attained a high reliability, and represents a crucial tool for the elaboration of field data obtained in pilot tests and for the design of the full-scale systems. Further research is needed to attain higher concentrations of chlorinated solvent degrading microbes and more reliable cost estimates. Lastly, a procedure for the design of full-scale in situ aerobic cometabolic bioremediation processes is proposed. PMID:25306537

  18. The role of natural chlorinated hydroquinone metabolites in ligninolytic fungi

    NARCIS (Netherlands)

    Teunissen, P.J.M.

    1999-01-01

    Ligninolytic Basidiomycetes have been reported to produce a wide variety of chloroaromatic compounds as secondary metabolites, which are structurally similar to environmental pollutants. Among these are chlorinated hydroquinone metabolites (CHM), such as 2-chloro-1,4-dimethoxybenzene (2Cl-14DMB), 2,

  19. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    OpenAIRE

    Ni, Z

    2015-01-01

      Subjects: bioremediation; biodegradation; environmental biotechnology, subsurface and groundwater contamination; biological processes; geochemistry; microbiology The combination of enhanced natural attenuation (ENA) of chlorinated volatile organic compounds (CVOCs) and aquifer thermal energy storage (ATES) appears attractive because such integration provides a promising solution for redevelopment of urban areas in terms of improving the local environmental quality as well as achieving ...

  20. The effect of chlorine dioxide on polymeric packaging materials

    Science.gov (United States)

    Chlorine dioxide (ClO2), with its high oxidizing capacity and broad disinfecting property, is used frequently as a disinfectant in many applications. As a biocide in food applications, it showed a microbial inactivating capacity against many important pathogenic and spoilage microorganisms, located ...