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Sample records for chlorine ions

  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. BEAM-FOIL SPECTROSCOPY OF CHLORINE AND SULFUR IONS

    OpenAIRE

    Frot, D.; Barchewitz, R.; Cukier, M.; Dei-Cas, R.; Bruneau, J

    1987-01-01

    We report on the measurement of spectra of highly stripped chlorine and sulfur ions in the energy ranges of, respectively, 2900 - 3500 eV and 2300 - 2600 eV. The spectra have been obtained after excitation of ions travelling through a thin carbon foil . X-rays emitted by the emerging beam are analyzed with a Johanntype bent crystal spectrometer. The observation angle with respect to the beam axis is 54°. The interpretation of the spectra is performed by comparing experimental results with Mul...

  4. Negative ion density in inductively coupled chlorine plasmas

    International Nuclear Information System (INIS)

    Laser photodetachment spectroscopy has been used to infer the density of chlorine negative ions in an inductively coupled chlorine plasma. Time dependent, excess electron density produced by photodetaching electrons from Cl- was detected by a microwave interferometer operating at 80 GHz. By focusing the microwave probe beam through the center of the discharge, negative ion density measurements could be performed in a small, 1.5 cm3, volume. As the rf power into the plasma increased from 155 to 340 W at 20 mTorr, the Cl- density in the center of the bulk plasma increased from 3.4 to 5.2x1011 cm-3. As the pressure was increased from 15 to 50 mTorr at 240 W, the Cl- density increased from 3.5 to 5x1011 cm3. Over this parameter space, the negative ion density equaled the electron density to within a factor of 2. The negative ion radial distribution was relatively constant, with a 20% decrease in the center of the plasma for some operating conditions. When the surface of the bias electrode was changed from stainless steel to silicon, the electron density remained constant but the Cl- density decreased by a factor of 2 to 3. copyright 1996 American Vacuum Society

  5. Ion Flux and Ion Energy Distributions in an Inductively Coupled GEC Rf Refererence Cell in Chlorine

    Science.gov (United States)

    Radovanov, Svetlana; Forrister, Ray; Anderson, Harold

    1996-10-01

    Ion flux and energy distribution measurements in pure chlorine were performed in an inductively coupled Gaseous Electronics Reference Cell 13.56 MHz radiofrequency discharge . Measurements were made using miniaturized gridded energy analyzer. This detector was developed at the University of New Mexico, based on earlier design of the small size energy analyzers at MIT. The detector was mounted on a 12 inch water cooled carrier to suppress probe heating. The probe could be radially moved in the discharge cell to monitor the radial uniformity of the plasma. In addition, the detector was protected with a ceramic coating to supress for the electron saturation current of unshielded probe areas. The measurements were done in the "bright " mode dominated by inductive coupling at different pressures and powers. The radial variation of the ion flux in pure chlorine and argon show similar strongly nonuniform profile. As expected, absolute ion flux values in chlorine are substantially decreased compared to pure argon discharge. The spatial nonuniformity across the 16 cm diameter surface of the grounded electrode is in agreement with the Langmuir probe measurements done by Miller and MIT measurements in pure argon. The ion energy distribution functions (IEDs) measured exhibit a complex structure indicative of both light Cl^+ and heavier Cl_2^+ ions. The IEDs in chlorine are much broder than those measured in pure argon plasma. The radial profile of IEDs found in the GEC/ICP chlorine discharge indicate large changes are occuring in the nature of power coupling to the discharge moving center to edge.

  6. Chlorine

    Science.gov (United States)

    ... chlorine gas are inhaled. Fluid in the lungs (pulmonary edema) that may be delayed for a few hours ... health problems such as fluid in the lungs (pulmonary edema) following the initial exposure. How people can protect ...

  7. Dry Machining Tool Design via Chlorine Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    TatsuhikoAizawa; AtsushiMitsuo; ShigeoYamamoto; ShinjiMuraishi; TaroSumitomo

    2004-01-01

    Dry machining has become a key issue to significantly reduce the wastes of used lubricants and cleaning agents and to improve the environmental consciousness for medical and food applications of special tooling. Since the tools and metallic works are in direct contact in dry, severe adhesive wear and oxidation are thought to occur even at the presence of hard protective coatings. Self-lubrication mechanism with use of lubricous oxide films is found to be effective for dry machining. Through the chlorine ion implantation to tools, titanium base oxides are in-situ formed on the tool surface. This oxide deforms elasto-plastically so that both friction coefficient and wear volume are reduced even in the high-speed cutting.

  8. Dry Machining Tool Design via Chlorine Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    Tatsuhiko Aizawa; Atsushi Mitsuo; Shigeo Yamamoto; Shinji Muraishi; Taro Sumitomo

    2004-01-01

    Dry machining has become a key issue to significantly reduce the wastes of used lubricants and cleaning agents and to improve the environmental consciousness for medical and food applications of special tooling. Since the tools and metallic works are in direct contact in dry, severe adhesive wear and oxidation are thought to occur even at the presence of hard protective coatings. Self-lubrication mechanism with use of lubricous oxide films is found to be effective for dry machining. Through the chlorine ion implantation to tools, titanium base oxides are in-situ formed on the tool surface.This oxide deforms elasto-plastically so that both friction coefficient and wear volume are reduced even in the high-speed cutting.

  9. Fluorine and chlorine determination in oxides and metals by ion chromatography

    International Nuclear Information System (INIS)

    Method for simultaneous determination of fluorine and chlorine microquantitie in tantalum, uranium and plutonium oxides, based on combined methods of pyrohydrolysis (1000-1100 deg C) and two-column ion chromatography with conductometric detection is suggested. The relative root-mean-square deviation of determination error is 0.2, the fluorine and chlorine content being 5·10-4 mass%

  10. Chlorine ions effect on photochemical activity of alcoholate complexes of vanadium

    International Nuclear Information System (INIS)

    Photochemical activity of vanadium complexes during alcogolate ion substitution by chlorine is studied. Using the method of electron spectroscopy and ESR photochemical transformations in alcohol solutions, containing alkoxides VO(OR)3, VO(OR)2Cl, VO(OR)Cl2 as well as VOCl3 with additions of HCl and LiCl, are investigated. It is shown that with the increase of chloride-ion concentration in solution the rate of all the stages of photochemical reduction of vanadium increases considerably. It is also found that photoreduction of vanadium (5) in the case of absence of chlorine ions ends at the stage of vanadium (3) complex formation, whereas when chlorine ions are present in solution the process proceeds further to the formation of divalent vanadium complexes

  11. An ion-selective electrode method for determination of chlorine in geological materials

    Science.gov (United States)

    Aruscavage, P. J.; Campbell, E.Y.

    1983-01-01

    A method is presented for the determination of chlorine in geological materials, in which a chloride-selective ion electrode is used after decomposition of the sample with hydrofluoric acid and separation of chlorine in a gas-diffusion cell. Data are presented for 30 geological standard materials. The relative standard deviation of the method is estimated to be better than 8% for amounts of chloride of 10 ??g and greater. ?? 1983.

  12. Effect of ferric and bromide ions on the formation and speciation of disinfection byproducts during chlorination

    Institute of Scientific and Technical Information of China (English)

    Shaogang Liu; Zhiliang Zhu; Yanling Qiu; Jianfu Zhao

    2011-01-01

    The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts (DBPs) during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon (TOC) and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions,four trihalomethanes (THMs), nine haloacetic acids (HAAs), total organic halogen (TOX) and its halogen species fractions, including total organic chlorine (TOC1) and total organic bromide (TOBr), were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species,which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.

  13. 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.

  14. Chlorine isotope effects in ion exchange reactions with a strongly basic anion exchanger

    International Nuclear Information System (INIS)

    As can be shown by the results of this study, the chemical preenrichment of the stable chlorine isotopes in inorganic ion-exchange equilibria is feasible in principle. This process should be performed in chromotographic separation columns at temperatures as low as possible. Because of the dependence of the isotopic effect on the elution medium concentration a very low concentration is desirable for the chemical enrichment process. Smaller elution concentrations however result in increasingly longer elution times. (HK)

  15. Thermal diffusion of chlorine in uranium dioxide studied by secondary ion mass spectrometry and X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    In a nuclear reactor, 35Cl present as an impurity in the nuclear fuel is activated by thermal neutron capture. During interim storage or geological disposal of the nuclear fuel, 36Cl may be released from the fuel to the geo/biosphere and contribute significantly to the 'instant release fraction'. In order to elucidate the diffusion mechanisms, both irradiation and thermal effects must be assessed. This paper deals with the thermal diffusion of chlorine in depleted UO2. For this purpose, sintered UO2 pellets were implanted with 37Cl at an ion fluence of 1013cm-2 and successively annealed in the 1175-1475K temperature range. The implanted chlorine is used to simulate the behaviour of the displaced one due to recoil and to interactions with the fission fragments during reactor operation. The behaviour of the pristine and the implanted chlorine was investigated during thermal annealing. SIMS and μ-XAS (at the Cl-K edge) analyses show that: (1) the thermal migration of implanted chlorine becomes significant at 1275K; this temperature and the calculated activation energy of 4.3eV points out the great ability of chlorine to migrate in UO2 at relatively low temperatures; (2) the behaviour of the implanted chlorine which aggregates into 'hot spots' during annealing before its effusion is clearly different from that of the pristine one which remains homogenously distributed after annealing; (3) the 'hot spot' and the pristine chlorine seem to be in different structural environments. Both types of chlorine are assumed to have a valence state of -I; (4) the comparison between an U2O2Cl5 reference compound and the pristine chlorine environment shows a contribution of the U2O2Cl5 to the pristine chlorine

  16. Stable Chlorine Isotopes and Elemental Chlorine by Thermal Ionization Mass Spectrometry and Ion Chromatography; Martian Meteorites, Carbonaceous Chondrites and Standard Rocks

    Science.gov (United States)

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

    2011-01-01

    Recently significantly large mass fractionation of stable chlorine isotopes has been reported for terrestrial and lunar samples [1,2]. In addition, in view of possible early solar system processes [3] and also potential perchlorate-related fluid/microbial activities on the Martian surface [4,5], a large chlorine isotopic fractionation might be expected for some types of planetary materials. Due to analytical difficulties of isotopic and elemental analyses, however, current chlorine analyses for planetary materials are controversial among different laboratories, particularly between IRMS (gas source mass spectrometry) and TIMS (Thermal Ionization Mass Spectrometry) groups [i.e. 1,6,7] for isotopic analyses, as well as between those doing pyrohydrolysis and other groups [i.e. 6,8]. Additional careful investigations of Cl isotope and elemental abundances are required to confirm real chlorine isotope and elemental variations for planetary materials. We have developed a TIMS technique combined with HF-leaching/ion chromatography at NASA JSC that is applicable to analysis of small amounts of meteoritic and planetary materials. We present here results for several standard rocks and meteorites, including Martian meteorites.

  17. Synergistic extraction of Eu(III) with N-phosphorylated bis-ureas and chlorinated cobalt bis(dicarbollide) ion

    Czech Academy of Sciences Publication Activity Database

    Selucký, P.; Bubeníková, M.; Rais, J.; Grüner, Bohumír; Brusko, V.V.

    2013-01-01

    Roč. 101, č. 1 (2013), s. 27-31. ISSN 0033-8230 R&D Projects: GA ČR GA104/09/0668 Institutional support: RVO:61388980 Keywords : liquid-liquid extraction * lanthanides * actinides * N-phosphorylated bis-ureas * chlorinated cobalt bis(dicarbollide) ion * high level liquid waste Subject RIV: CA - Inorganic Chemistry Impact factor: 1.411, year: 2013

  18. Determination of haloacetic acids concentrations in hospital effluent after chlorination by ion chromatography

    Institute of Scientific and Technical Information of China (English)

    SUN Ying-xue; GU Ping

    2007-01-01

    The ion chromatography combined solid phase extraction (SPE) method was developed for the analysis of low concentration haloacetic acids(HAAs),a calss of disinfection by-products formed as a result of chlorination of hospital wastewater. The monitored HAAs included monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid and trichloroacetic acid. The method employed a sodium hydroxide eluent at a flow rate of 0.8 ml/min, electrolytically generated gradients, and suppressed conductivity detection. To analyze the HAAs in real hospital wastewater samples, C18 pretreatment cartridge was utilized to reduce samples' turbidity. Preconcentration with SPE and matrix elimination with treatment cartridges were investigated and were found to be able to obtain acceptable detection limits. Linearity, repeatability and detection limits of the above method were evaluated. The detection limits of monobromoacetic acid and dibromoacetic acid were 2.61 μg/L and 1.30 μg/L respectively, and the other three are ranging from 0.48 to 0.82 μg/L under 25-fold preconcentration. When the above optimization procedure was applied to three hospital wastewater samples with different treatment processes in Tianjin, it was found that the dichloroacetic acid is the major compound, and the growth ratios of the HAAs after disinfection by sodium hypochlorite were 91.28%, 63.61% and 79.50%, respectively.

  19. Negative chlorine ion chemistry in the upper stratosphere and its application to an artificially created dense electron cloud

    Directory of Open Access Journals (Sweden)

    S. S. Prasad

    Full Text Available This paper discusses new potential reactions of chlorine-bearing anions (negative ions in the upper stratosphere. These reactions are then applied to the negative-ion chemistry following the injection of an electron cloud of very high density, of the order of 106-107 e- cm-3, in the 40-45-km region. The idea is to evaluate the recently proposed scheme to mitigate ozone depletion by converting the reactive chlorine atoms at these altitudes into Cl- ions which are unreactive towards ozone, i.e., electron scavenging of Cl. We find that the previously neglected photodetachment from Cl- is fast. For an overhead sun, this process may have a rate coefficient of 0.08 s-1 when multiple scattering is included. The rate could be even higher, depending on the ground albedo. Switching reaction between Cl-·H2O and HCl might lead to the formation of Cl-·HCl anion. Possible reactions of Cl-·H2O and Cl-·HCl with O atoms could produce ClO- and Cl-2. The production of ClO- in this manner is significant because Cl- having a high photodetachment rate constant would be regenerated in the very likely reactions of ClO- with O. When these possibilities are considered, then it is found that the chlorine anions may not be the major ions inside the electron cloud due to the rapid photodetachment from Cl-. Furthermore, in such a cloud, there may be the hazard that the Cl--Cl-·H2O-ClO--Cl- cycle amounts to catalytic destruction of two O atoms. Thus, the scheme could be risky if practised in the altitude region where atomic oxygen is an important constituent. Similar conclusions apply even if the ClO- species forms ClO-3 by three-body association with O2

  20. Valence-shell single photoionization of Chlorine-like K$^{2+}$ ions: Experiment and Theory

    CERN Document Server

    Alna'Washi, G A; Habibi, M; Esteves-Macaluso, D; Wang, J C; Phaneuf, R A; Kilcoyne, A L D; Cisneros, C; McLaughlin, B M

    2014-01-01

    The absolute single photoionization cross-section was measured for Cl-like K$^{2+}$ over the photon energy range from 44.2 - 69.7 eV at a constant energy resolution of 0.045 eV. The experiments were performed by merging an ion beam with a beam of synchrotron radiation from an undulator. The ground-state ionization threshold was measured at 0.004 eV energy resolution to be 45.717 $\\pm$ 0.030 eV. The measurements are rich in resonance structure due to multiple Rydberg series of transitions to autoionizing states. These series are assigned spectroscopically using the quantum defect method, guided by pseudo-relativistic Hartree-Fock calculations for the energies and oscillator strengths of transitions to autoionizing states. The experimental results, which include significant contributions from K$^{2+}$ ions initially in metastable states, are in satisfactory agreement with a linear superposition of semi-relativistic R-matrix calculations of photoionization cross sections from these initial states.

  1. Chapter 6. Uranium extraction possibilities from natural uranium-bearing waters of complex salt composition. 6.2. Technology for uranium extraction from brine with a high content of ion-chlorine

    International Nuclear Information System (INIS)

    Present article is devoted to technology for uranium extraction from brine with a high content of ion-chlorine. The content of basic anions and cations in lake waters of Sasik-Kul deposit was defined. Results of X-ray spectral analysis of salt residual after water evaporation from Sasik-Kul lake was discussed. Investigations revealed that uranium extraction from brines containing ion-chlorine is possible. The developed basic process flow diagram of uranium extraction from Sasik-Kul Lake' brine consists of the following basic stages: evaporation, leaching, catching of formed gases (HCl), sorption, desorption, deposition, drying and tempering.

  2. 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...

  3. Ion irradiation of 37Cl implanted nuclear graphite: Effect of the energy deposition on the chlorine behavior and consequences for the mobility of 36Cl in irradiated graphite

    International Nuclear Information System (INIS)

    Graphite is used in many types of nuclear reactors due to its ability to slow down fast neutrons without capturing them. Whatever the reactor design, the irradiated graphite waste management has to be faced sooner or later regarding the production of long lived or dose determining radioactive species such as 14C, 3H or 36Cl. The first carbon dioxide cooled, graphite moderated nuclear reactors resulted in a huge quantity of irradiated graphite waste for which the management needs a previous assessment of the radioactive inventory and the radionuclide’s location and speciation. As the detection limits of usual spectroscopic methods are generally not adequate to detect the low concentration levels (<1 ppm) of the radionuclides, we used an indirect approach based on the implantation of 37Cl, to simulate the presence of 36Cl. Our previous studies show that temperature is one of the main factors to be considered regarding the structural evolution of nuclear graphite and chlorine mobility during reactor operation. However, thermal release of chlorine cannot be solely responsible for the depletion of the 36Cl inventory. We propose in this paper to study the impact of irradiation and its synergetic effects with temperature on chlorine release. Indeed, the collision of the impinging neutrons with the graphite matrix carbon atoms induces mainly ballistic collisions. However, a small part of the recoil carbon atom energy is also transferred to the lattice through electronic excitation. This paper aims at elucidating the effects of the different irradiation regimes (ballistic and electronic) using ion irradiation, on the mobility of implanted 37Cl, taking into account the initial disorder level of the nuclear graphite

  4. Ion irradiation of 37Cl implanted nuclear graphite: Effect of the energy deposition on the chlorine behavior and consequences for the mobility of 36Cl in irradiated graphite

    Science.gov (United States)

    Toulhoat, N.; Moncoffre, N.; Bérerd, N.; Pipon, Y.; Blondel, A.; Galy, N.; Sainsot, P.; Rouzaud, J.-N.; Deldicque, D.

    2015-09-01

    Graphite is used in many types of nuclear reactors due to its ability to slow down fast neutrons without capturing them. Whatever the reactor design, the irradiated graphite waste management has to be faced sooner or later regarding the production of long lived or dose determining radioactive species such as 14C, 3H or 36Cl. The first carbon dioxide cooled, graphite moderated nuclear reactors resulted in a huge quantity of irradiated graphite waste for which the management needs a previous assessment of the radioactive inventory and the radionuclide's location and speciation. As the detection limits of usual spectroscopic methods are generally not adequate to detect the low concentration levels (<1 ppm) of the radionuclides, we used an indirect approach based on the implantation of 37Cl, to simulate the presence of 36Cl. Our previous studies show that temperature is one of the main factors to be considered regarding the structural evolution of nuclear graphite and chlorine mobility during reactor operation. However, thermal release of chlorine cannot be solely responsible for the depletion of the 36Cl inventory. We propose in this paper to study the impact of irradiation and its synergetic effects with temperature on chlorine release. Indeed, the collision of the impinging neutrons with the graphite matrix carbon atoms induces mainly ballistic collisions. However, a small part of the recoil carbon atom energy is also transferred to the lattice through electronic excitation. This paper aims at elucidating the effects of the different irradiation regimes (ballistic and electronic) using ion irradiation, on the mobility of implanted 37Cl, taking into account the initial disorder level of the nuclear graphite.

  5. Adsorption of Rh(III) complexes from chloride solutions obtained by leaching chlorinated spent automotive catalysts on ion-exchange resin Diaion WA21J

    International Nuclear Information System (INIS)

    It was found that Rh, Pd and Pt contained in the spent ceramic automotive catalysts could be effectively extracted by dry chlorination with chlorine. In order to concentrate Rh(III) ions contained in the chloride solutions obtained, thermodynamic and kinetics studies for adsorption of Rh(III) complexes from the chloride solutions on an anionic exchange resin Diaion WA21J were carried out. Rh, Pd, Pt, Al, Fe, Si, Zn and Pb from the chloride solution could be adsorbed on the resin. The distribution coefficients (Kd) of Rh(III) decreased with the increase in initial Rh(III) concentration or in adsorption temperature. The isothermal adsorption of Rh(III) was found to fit Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich models under the adsorption conditions. The maximum monolayer adsorption capacities Qmax based on Langmuir adsorption isotherms were 6.39, 6.61 and 5.81 mg/g for temperatures 18, 28 and 40 deg. C, respectively. The apparent adsorption energy of Rh was about -7.6 kJ/mol and thus Rh(III) adsorption was a physical type. The experimental data obtained could be better simulated by pseudo-first-order kinetic model and the activation energy obtained was 6.54 J/mol. The adsorption rate of Rh(III) was controlled by intraparticle diffusion in most of time of adsorption process.

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

    Science.gov (United States)

    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...

  7. The energy levels and transition probabilities for silicon, phosphorous, sulfur, and chlorine ions of the boron iso-electronic sequence

    International Nuclear Information System (INIS)

    The slater type radial wave functions of the 1S, 2S, and 2P orbitals have been employed in order to construct the hartree-fock (HF) wave functions of the ground states 1S2 2S2 2P for Si X, ph XI, S XII and C1 XIII of the boron iso-electronic sequence. The radial functions of the excited orbitals ns, np, and nf (n=3-5) have been optimized using the CIV3 code which uses the multi-configuration hartree-fock (MCHF) method in evaluating these functions. The wave functions thus obtained have been used in calculating energy levels, oscillator strengths and transition probabilities. The calculated energies (in au) relative to the ground state were in a good agreement with the available published experimental and theoretical values within the experimental error for all levels of the ions of the sequence except for the 3 p, 4 p, and 5 p levels of Si X, Ph XI, S XII and CI XIII. The deviation may be attributed to relativistic effects in case of highly ionized members of the sequence. The oscillator strengths for the allowed electric dipole transitions have been computed in dipole-length from by using the same code. The transition probabilities for spontaneous emission Aji (sec1) are calculated using the equation Aji=6.6 x 1015 gi fij / Lambda2 gj (sec1) where lambda is the wavelength of the transition (in A0) from state (i) to state (j) and gi. gj are the statistical weights for these states, fg is the oscillator strength of the transition. More over results of oscillator strengths and transition probabilities are found to be in a fairly good agreement with the available published experimental and theoretical values

  8. 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.)

  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. Determination of fluorine and chlorine in geological materials by induction furnace pyrohydrolysis and standard-addition ion-selective electrode measurement.

    Science.gov (United States)

    Rice, T D

    1988-03-01

    Fluorine and chlorine in geological materials are volatilized by pyrohydrolysis at about 1150 degrees in a stream of oxygen (1000 ml/min) plus steam in an induction furnace. The catalyst is a 7:2:1 mixture of silica gel, tungstic oxide and potassium dihydrogen phosphate. The sample/catalyst mixture is pyrohydrolysed in a re-usable alumina crucible (already containing four drops of 1 + 3 phosphoric acid) inserted in a silica-enclosed graphite crucible. The absorption solution is buffered at pH 6.5 and spiked with 1.6 mug of fluoride and 16 mug of chloride per g of solution, to ensure rapid and linear electrode response during subsequent standard-addition measurement. The simple plastic absorption vessel has 99.5% efficiency. The 3s limits of detection are 5-10 mug/g and 40-100 mug/g for fluorine and chlorine respectively. The procedure is unsuitable for determining chlorine in coal. PMID:18964490

  11. Ion irradiation of {sup 37}Cl implanted nuclear graphite: Effect of the energy deposition on the chlorine behavior and consequences for the mobility of {sup 36}Cl in irradiated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Toulhoat, N., E-mail: nelly.toulhoat@univ-lyon1.fr [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); CEA/DEN, Centre de Saclay (France); Moncoffre, N. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Bérerd, N.; Pipon, Y. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Université de Lyon, Université Lyon, IUT Lyon-1 département chimie (France); Blondel, A. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Andra, Châtenay-Malabry (France); Galy, N. [Université de Lyon, Université Lyon 1, CNRS/IN2P3, UMR5822, Institut de Physique Nucléaire de Lyon (IPNL) (France); Sainsot, P. [Université de Lyon, Université Lyon 1, LaMCoS, INSA-Lyon, CNRS UMR5259 (France); Rouzaud, J.-N.; Deldicque, D. [Laboratoire de Géologie de l’Ecole Normale Supérieure (ENS), Paris, UMR CNRS-ENS 8538 (France)

    2015-09-15

    Graphite is used in many types of nuclear reactors due to its ability to slow down fast neutrons without capturing them. Whatever the reactor design, the irradiated graphite waste management has to be faced sooner or later regarding the production of long lived or dose determining radioactive species such as {sup 14}C, {sup 3}H or {sup 36}Cl. The first carbon dioxide cooled, graphite moderated nuclear reactors resulted in a huge quantity of irradiated graphite waste for which the management needs a previous assessment of the radioactive inventory and the radionuclide’s location and speciation. As the detection limits of usual spectroscopic methods are generally not adequate to detect the low concentration levels (<1 ppm) of the radionuclides, we used an indirect approach based on the implantation of {sup 37}Cl, to simulate the presence of {sup 36}Cl. Our previous studies show that temperature is one of the main factors to be considered regarding the structural evolution of nuclear graphite and chlorine mobility during reactor operation. However, thermal release of chlorine cannot be solely responsible for the depletion of the {sup 36}Cl inventory. We propose in this paper to study the impact of irradiation and its synergetic effects with temperature on chlorine release. Indeed, the collision of the impinging neutrons with the graphite matrix carbon atoms induces mainly ballistic collisions. However, a small part of the recoil carbon atom energy is also transferred to the lattice through electronic excitation. This paper aims at elucidating the effects of the different irradiation regimes (ballistic and electronic) using ion irradiation, on the mobility of implanted {sup 37}Cl, taking into account the initial disorder level of the nuclear graphite.

  12. Characters of chlorine isotopic composition in ocean water

    Digital Repository Service at National Institute of Oceanography (India)

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

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  14. 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...

  15. 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…

  16. Chlorine solar neutrino experiment

    International Nuclear Information System (INIS)

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

  17. Design chlorine ions and PH detector based on the color sensor TCS230%基于颜色传感器TCS230的氯离子和PH检测仪设计

    Institute of Scientific and Technical Information of China (English)

    张波; 陆瑶成; 陈宵燕; 尤丽华

    2013-01-01

    In order to detection chlorine ions and PH of the daily water consumption accurately and rapidly, the microcontroller AT89S52 and high-resolution programmable color sensor TCS230 are combined, proposed a new method of testing chloride ion and PH based on the color sensor TCS230, given the instrument hardware design circuit and the output of the program flow of the test results. TCS230 converted the color of PH and chloride ion strips into the color components directly, after the microcontroller processing give the test results.%为了方便对日常用水氯离子和PH精确快速检测,将单片机AT89S52与高分辨率可编程颜色传感器TCS230相结合,提出了一种基于颜色传感器TCS230的氯离子和PH检测的新方法,给出了该仪器的硬件设计电路以及输出检测结果的程序流程.TCS230直接将PH试纸和氯离子试纸的颜色转换成颜色分量,经过单片机处理得到检测结果.

  18. 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...

  19. Chlorine trifluoride (1963)

    International Nuclear Information System (INIS)

    This monograph on chlorine trifluoride may be considered as a working tool useful in gaseous diffusion research. It consists of data gathered from the literature and includes furthermore a certain amount of original data. This monograph groups together the physical, chemical and physiological properties of chlorine trifluoride, as well as the preparation and analytical methods. It has been thought wise to add some technological information, and the safety regulations governing its use. (authors)

  20. 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)

  1. Simultaneous chlorination and sulphation of calcined limestone

    Energy Technology Data Exchange (ETDEWEB)

    Matsukata, M.; Takeda, K.; Miyatain, T.; Ueyama, K. [Osaka University, Osaka (Japan). Dept. of Chemical Engineering

    1996-06-01

    In order to analyze HCl and SO{sub 2} retention in fluidized bed combustors of coal and wastes, chlorination and sulphation of calcined limestone were investigated at 1023 K and atmospheric pressure using thermogravimetry. The rate of chlorination of calcined limestone slightly depended on its particle size and was kept almost constant against the progress of chlorination. In contrast, the rate of sulphation increased with decreasing particle size and steeply decreased with the progress of sulphation as commonly reported. It was found that the sulphation was markedly accelerated in the presence of HCl. Such acceleration of sulphation was remarkable for larger limestone. The level of conversion of CaO to (CaSO{sub 4} + CaCl{sub 2}) always approached 100% in the simultaneous absorption of HCl and SO{sub 2}. It was observed by SEM that in the chlorination a number of spherical aggregates and large voids were formed on the surface of limestone and that large aggregates with very flat surface and large voids have been formed in the course of the simultaneous chlorination and sulphation. The chlorination behavior and the acceleration of SO{sub 2} absorption in the presence of HCl can be due both to the formation of a mobile Cl{sup -} ion-containing phase and to the formation of voids playing a role of the diffusion paths for HCl and SO{sub 2} toward the interior of a limestone particle. Melting of a eutectic mixture of CaCl{sub 2} and CaSO{sub 4} might largely contribute to the promotion of SO{sub 2} absorption in the case of simultaneous absorption of HCl and SO{sub 2}. 8 refs., 4 figs.

  2. 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...

  3. 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)

  4. Physico-chemical behaviour of a metal/polymer contact subject to a low amplitude friction in a chlorinated medium. Effect of ionitriding and ion implantation surface treatment

    International Nuclear Information System (INIS)

    The fretting-corrosion behaviour of two tribological couples (TA6V/PMMA and 316L/PMMA) had been studied in order to better understand the degradation mechanisms observed on pivot prosthesis sealed in bones. Pressure appears to have a major role; at high contact pressure, the PMMA wear is the main degradation mechanism with PMMA debris acting as a metal surface protecting agent; at low contact pressure, both material deterioration is involved, and titanium has a corrosion-dominated degradation. An optimal resistance to fretting is achieved when TA6V is coated with Ti N (ion implantation) and Ti N, Ti2 N (ionitriding). When nitriding, processing temperature appears as a critical factor to ensure thickness and homogeneity of the nitride coatings. 181 p., 106 figs., 110 refs

  5. Chlorination of zirconyte concentrate

    International Nuclear Information System (INIS)

    Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO2 gasification. (author)

  6. 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 ...

  7. 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)

  8. 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

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

    Science.gov (United States)

    Powell, Joshua; Luh, Jeanne; Coronell, Orlando

    2014-01-01

    We studied the volume-averaged chlorine (Cl) uptake into the bulk region of the aromatic polyamide active layer of a reverse osmosis membrane upon exposure to free chlorine. Volume-averaged measurements were obtained using Rutherford backscattering spectrometry with samples prepared at a range of free chlorine concentrations, exposure times, and mixing, rinsing, and pH conditions. Our volume-averaged measurements complement previous studies that have quantified Cl uptake at the active layer surface (top ≈ 7 nm) and advance the mechanistic understanding of Cl uptake by aromatic polyamide active layers. Our results show that surface Cl uptake is representative of and underestimates volume-averaged Cl uptake under acidic conditions and alkaline conditions, respectively. Our results also support that (i) under acidic conditions, N-chlorination followed by Orton rearrangement is the dominant Cl uptake mechanism with N-chlorination as the rate-limiting step; (ii) under alkaline conditions, N-chlorination and dechlorination of N-chlorinated amide links by hydroxyl ion are the two dominant processes; and (iii) under neutral pH conditions, the rates of N-chlorination and Orton rearrangement are comparable. We propose a kinetic model that satisfactorily describes Cl uptake under acidic and alkaline conditions, with the largest discrepancies between model and experiment occurring under alkaline conditions at relatively high chlorine exposures. PMID:24506252

  10. 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...

  11. 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.

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

    International Nuclear Information System (INIS)

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

  13. Radiochemical analysis of chlorine-36

    International Nuclear Information System (INIS)

    The aim of this paper is to propose a radiochemical separation method of chlorine-36 from other beta-gamma emitters based on an oxidation technique where chlorine is trapped by NaOH. Chlorine-36 beta emissions are measured by liquid scintillation counting by the dual label technique in order to avoid the contamination produced by carbon-14 which is also trapped by NaOH and it is the main contaminant present in graphite samples. The sensitivity of this radiochemical method is high enough to achieve the needed thresholds for the radiological characterization of the radioactive materials in which this method can be applied

  14. 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)

  15. 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

  16. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

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

    1998-01-01

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

  17. 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.

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  19. Effects of Chlorine on Enterovirus RNA Degradation

    Science.gov (United States)

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

  20. 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.

  1. 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...

  2. Reducing chlorination of niobium pentoxide

    International Nuclear Information System (INIS)

    Studies of cylindric briquettes of Nb2O5 and carbon are presented. The effects of chlorine flow, dimension of the briquettes, porosity, percentage of the reducing agent in the mixture and temperature are analysed. The volatilization aspect of Nb2O5 by the briquettes and the structural transformations of the samples are described. (M.A.C.)

  3. Novel chlorinated derivatives of BODIPY

    OpenAIRE

    Garcia-Moreno, I.; Costela González, Ángel; Chiara, José Luis; Duran-Sampedro, G.; Ortiz, M. J.; Rodríguez Agarrabeitia, Antonio

    2012-01-01

    [EN] The invention relates to the use of novel dyes with a BODIPY structure, characterised in that they contain at least one chlorine atom bound to the carbons of the boradiazaindacene system, to the use thereof as laser dyes and fluorescent markers, and to a method for obtaining some of these compounds.

  4. 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.

  5. 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.

  6. 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.

  7. Water Chlorination for human consumption

    International Nuclear Information System (INIS)

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

  8. Metabolic fate of chlorinated paraffins

    International Nuclear Information System (INIS)

    The disposition of three [1-14C]-chlorododecanes (MCDD, PCDD I and PCDD II; 17.4%, 55.9%, and 68.5% chlorination) was studied in C57Bl mice. [1-14C]-lauric acid (LA) was studied as reference compound. Fifty-two percent (MCDD), 32% (PCDD I), and 8% (PCDD II) of the radioactive doses were exhaled as 14CO2 during 12 h after i.v. injection. Similar results were obtained after p.o. administration. In addition to a marked labelling of the liver and fat, the distribution patterns observed at 24 h after administration revealed an uptake of radioactivity in tissues with high cell turnover/high metabolic activity, e.g., intestinal mucosa, bone marrow, salivary glands and thymus. The concentration of radioactivity in these sites and the exhalation of 14CO2, which were inverse to the degree of chlorination, indicate that the chloroalkanes are degraded to metabolites which can be utilized in the intermediary metabolism. A similar, although more pronounced, distribution pattern and 14CO2-exhalation (70% of i.v. dose) was observed after LA administration. The long time retention of heptane-soluble radioactivity in liver and fat (indicating unmetabolized substance) increased with degree of chlorination. On the contrary, the administration of LA and the chlorododecanes MCDD and PCDD I, but not of PCDD II, resulted in a selective labelling of the central nervous system 30-60 days after injection. (orig.)

  9. Session 6: The catalytic oxidation of selected chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Oszczudlowski, J. [Institute of Chemistry, Swietokrzyska Academy, Kielce (Poland)

    2004-07-01

    The catalytic oxidation of selected chlorinated hydrocarbons was investigated in the presence of natural zeolites modified with 3M HCl and chromium and lanthanum from aqueous solutions. Natural zeolites of the structure of clinoptilolite or mordenite possess unique physical and chemical properties such as high sorptive capacity and ion-exchange selectivity, relatively high heat and mechanical resistance. The activation of samples of natural zeolites was carried out in a 3M aqueous solution of HCl using a Soxhlet apparatus, whereas the ion exchange from aqueous solutions of chromium (III) and lanthanum (III) nitrates. Samples of activated zeolites were calcinated at 500 C with a programmable temperature increase within 4 hours The amounts of Cr and La on zeolite were 3,0 % wt and 4,5 % wt, respectively. Catalytic tests were conducted in a micro-reactor coupled with a gas chromatograph. The conditions of reaction were as follows: temperature range: 473-723 K, substrate composition: chlorinated hydrocarbon (1000-10000 ppm), steam (0-10000 ppm) and air. Under standard conditions volatile chlorinated hydrocarbons were introduced into a gas flux as vapours, whereas low-volatile ones in a mixture with n-hexane or cyclohexane. The quantity of the deposits on the surface of a catalyst was analysed by the thermogravimetric and GC-MS methods. The composition of oxidation products of chlorinated hydrocarbons was chromatographically analysed indirectly with the techniques SPME-GC-ECD and SPME-GCFID. The total quantity of the products was stored in gas containers-Tedlars and the quantitative and qualitative composition was analysed by the method SPME-HS-GC-ECD (solid phase micro-extraction-headspace-gas chromatography-electron capture detector). The total oxidation of CCl{sub 4} and C{sub 2}Cl{sub 6} in the presence of the Cr/zeolite catalyst occurs at 400 C. The conversion of the catalytic oxidation of chloro-olefins in the presence of the La/zeolite catalyst increases within

  10. 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

  11. 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 ...

  12. Development and evaluation of analytical techniques for total chlorine in used oils and oil fuels

    International Nuclear Information System (INIS)

    A current EPA regulation prohibits the sale for burning in nonindustrial boilers of used oils and oil fuels. This paper discusses how analytical techniques for determining total chlorine were evaluated to provide regulatory agencies and the regulated community with appropriate chlorine test methods. The techniques evaluated included oxygen bomb combustion followed by chemical titration or ion chromatography, instrumental microcoulometry, field test kits, and instrumental furnace/specific ion electrode determinator, a device based on the Beilstein reaction, and x-ray fluorescence spectrometry. These techniques were subjected to interlaboratory testing to estimate their precision, accuracy, and sensitivity. Virgin and used crankcase oils, hydraulic and metalworking oils, oil fuels and oil fuel blends with used oils were tested. The bomb techniques, one of the test kits, microcoulometry and all but one x-ray analyzer were found to be suitable for this application. The chlorine furnace and the Beilstein device were found to be inapplicable at the levels of interest

  13. The continuous chlorination of plutonium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, M.J.

    1959-08-14

    Previous reports on the chlorination of plutonium dioxide describe numerous small-scale experiments and a few fair-sized batch preparations. The chemistry of chlorination by numerous reagents is covered, but no process had received sufficient study for large-scale preparation of anhydrous plutonium trichloride. The literature search revealed no extensive studies on chlorination rates, exhaust gas filtering, atmospheric requirements, reactor materials, etc. A program was undertaken to select a chlorination process, to develop the necessary information for defining operating conditions and equipment specifications, and then to demonstrate the operation of the process.

  14. Potassium chloride production by microcline chlorination

    International Nuclear Information System (INIS)

    Highlights: • Use of chlorination for the KCl production. • The reagents used were microcline, hydromagnesite and chlorine. • Isothermal and non-isothermal assays were performed in Cl2–N2 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

  15. 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.

  16. 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...

  17. 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)

  18. MICROCOSM STUDY OF DEGRADATION OF CHLORINATED SOLVENTS ON SYNTHETIC GREEN RUST MINERALS

    Science.gov (United States)

    Green rust minerals contain ferrous ion in their structure that can potentially serve as a chemical reductant for degradation of chlorinated solvents. Green rusts are found in zerovalent iron based permeable reactive barriers and in certain soil and sediments. Some previous labor...

  19. Salt stabilizer for preventing chlorine depletion and increasing shelf-life of potable water - A concept

    Science.gov (United States)

    Copeland, E. J.; Edgerley, R. H.

    1971-01-01

    Proposed concept, based on law of mass action uses addition of salt to increase chlorine ions produced in sodium hydrochlorite solutions, thereby increasing solution shelf-life. This technique is not costly. Usefulness will be determined by acceptability of salt in product undergoing long shelf-life.

  20. 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...

  1. 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...

  2. Hydrothermal Synthesis of Indium Tin Oxide Nanoparticles without Chlorine Contamination

    International Nuclear Information System (INIS)

    Indium tin oxide (In2Sn1-xO5-y) nanoparticles were synthesized by hydrothermal method from stable indium tin acetylacetone complexes and post annealing at 600 .deg. C. The absence of chlorine ions shortened the synthesis process, decreased the particle agglomeration and improved the particle purity. The introduced complexing ligand acetylacetone decreased the obtained nanoparticle size. The improved powder properties accelerated the sintering of the In2Sn1-xO5-y nanoparticles and reached a relative density of 96.4% when pressureless sintered at 1400 .deg. C

  3. Chlorine-based plasma etching of GaN

    Energy Technology Data Exchange (ETDEWEB)

    Shul, R.J.; Briggs, R.D. [Sandia National Labs., Albuquerque, NM (United States); Pearton, S.J.; Vartuli, C.B.; Abernathy, C.R.; Lee, J.W. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Constantine, C.; Baratt, C. [Plasma-Therm, Inc., Saint Petersburg, FL (United States)

    1997-02-01

    The wide band gap group-III nitride materials continue to generate interest in the semiconductor community with the fabrication of green, blue, and ultraviolet light emitting diodes (LEDs), blue lasers, and high temperature transistors. Realization of more advanced devices requires pattern transfer processes which are well controlled, smooth, highly anisotropic and have etch rates exceeding 0.5 {micro}m/min. The utilization of high-density chlorine-based plasmas including electron cyclotron resonance (ECR) and inductively coupled plasma (ICP) systems has resulted in improved GaN etch quality over more conventional reactive ion etch (RIE) systems.

  4. 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)

  5. 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...

  6. 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.

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

    International Nuclear Information System (INIS)

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

  8. Structure-property relationships for self-assembled zinc chlorin light-harvesting dye aggregates.

    Science.gov (United States)

    Huber, Valerie; Sengupta, Sanchita; Würthner, Frank

    2008-01-01

    A series of zinc 3(1)-hydroxymethyl chlorins 10 a-e and zinc 3(1)-hydroxyethyl chlorins 17 with varied structural features were synthesized by modifying naturally occurring chlorophyll a. Solvent-, temperature-, and concentration-dependent UV/Vis and CD spectroscopic methods as well as microscopic investigations were performed to explore the importance of particular functional groups and steric effects on the self-assembly behavior of these zinc chlorins. Semisynthetic zinc chlorins 10 a-e possess the three functional units relevant for self-assembly found in their natural bacteriochlorophyll (BChl) counterparts, namely, the 3(1)-OH group, a central metal ion, and the 13(1) C==O moiety along the Qy axis, and they contain various 17(2)-substituents. Depending on whether the zinc chlorins have 17(2)-hydrophobic or hydrophilic side chains, they self-assemble in nonpolar organic solvents or in aqueous media, respectively. Zinc chlorins possessing at least two long side chains provide soluble self-aggregates that are stable in solution for a prolonged time, thus facilitating elucidation of their properties by optical spectroscopy. The morphology of the zinc chlorin aggregates was elucidated by atomic force microscopy (AFM) studies, revealing well-defined nanoscale rod structures for zinc chlorin 10 b with a height of about 6 nm. It is worth noting that this size is in good accordance with a tubular arrangement of the dyes similar to that observed in their natural BChl counterparts in the light-harvesting chlorosomes of green bacteria. Furthermore, for the epimeric 3(1)-hydroxyethyl zinc chlorins 17 with hydrophobic side chains, the influence of the chirality center at the 3(1)-position on the aggregation behavior was studied in detail by UV/Vis and CD spectroscopy. Unlike zinc chlorins 10, the 3(1)-hydroxyethyl zinc chlorins 17 formed only small oligomers and not higher rod aggregate structures, which can be attributed to the steric effect imposed by the additional

  9. Removal of iodide from water by chlorination and subsequent adsorption on powdered activated carbon.

    Science.gov (United States)

    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-Cl₂/L) removed 90% of the iodine in NOM-containing water (dissolved organic carbon concentration, 1.5 mg-C/L). Iodine removal in NOM-containing water increased with increasing chlorine dose up to 0.1 mg-Cl₂/L but decreased at chlorine doses of >1.0 mg-Cl₂/L. At a low chlorine dose, nonadsorbable iodide ion (I⁻) was oxidized to adsorbable hypoiodous acid (HOI). When the chlorine dose was increased, some of the HOI reacted with NOM to form adsorbable organic iodine (organic-I). Increasing the chlorine dose further did not enhance iodine removal, owing to the formation of nonadsorbable iodate ion (IO₃⁻). Co-existing Br⁻ depressed iodine removal, particularly in NOM-free water, because hypobromous acid (HOBr) formed and catalyzed the oxidation of HOI to IO₃⁻. However, the effect of Br⁻ was small in the NOM-containing water because organic-I formed instead of IO₃⁻. SPAC (median particle diameter, 0.62 μm) had a higher equilibrium adsorption capacity for organic-I than did conventional PAC (median diameter, 18.9 μm), but the capacities of PAC and SPAC for HOI were similar. The reason for the higher equilibrium adsorption capacity for organic-I was that organic-I was adsorbed principally on the exterior of the PAC particles and not inside the PAC particles, as indicated by direct visualization of the solid-phase iodine concentration profiles in PAC particles by field emission electron probe microanalysis. In contrast, HOI was adsorbed evenly throughout the entire PAC particle. PMID:25462731

  10. 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.)

  11. 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 ...

  12. MECHANISM OF FUSARIUM TRICINCTUM (CORDA) SACC. SPORE INACTIVATION BY CHLORINE DIOXIDE

    OpenAIRE

    Zhao Chen

    2015-01-01

    The mechanism of Fusarium tricinctum (Corda) Sacc. spore inactivation by chlorine dioxide (ClO2) was investigated. During F. tricinctum spore inactivation by ClO2, protein, DNA, and metal ion leakage, enzyme activity, and cell ultrastructure were examined. Protein and DNA leakages were not detected, while there were metal ion leakages of K+, Ca2+, and Mg2+, which were well-correlated with the inactivation rate. The enzyme activities of glucose-6-phosphate dehydrogenase, citrate synthase, and ...

  13. Experimental study on the influence of charge exchange on the stopping power in the interaction of chlorine with a gas and a deuterium plasma; Etude experimentale de l`influence des echanges de charges sur le pouvoir d`arret dans l`interaction d`ions chlore avec un gaz et un plasma de deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Nectoux, Marie [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1998-01-06

    This thesis is placed in the context of the physics of energy deposition of a multicharged heavy ion beam in matter at intermediate energies. The experiment gave measurements of energy loss as a function of final charge state for chlorine ions at 1.7 MeV/u in deuterium gas or plasma. In this way, we explore the influence of charge state evolution, depending on experimentally measured capture and ionization cross sections and the electron density of the target, on energy loss. The target is cylindrical and enclosed by two fast valves. The plasma is created in the gas by a discharge, which induces a magnetic perturbation of the beam (lens effect). This effect induces a divergent and misaligned outgoing beam. A simulation including charge state and velocity evolution of the projectile in flight in the magnetic field has been made in order to optimize beam analysis, to reach a precision better than 10{sup -3} in energy measurement. This study led to removal of the target to the `Split Pole`, a refocusing magnetic spectrometer. The first results obtained clearly show the dependence of energy loss on exit charge and especially on its evolution in the target. This is explained in terms of the lengths covered by the projectile in its successive charge states in the target, which depends on target electron density and the medium considered. In plasma, we observed an energy distribution with exit charge twice that observed in gas, because of a strong decrease of charge exchange. A comparison of data obtained in gas with stopping power calculated from Bethe-Bloch-Barkas theory leads to the necessity of including spatial extension of the projectile charge in the theory. (author) 81 refs., 62 figs., 5tabs.

  14. 离子交换法从糖蜜中吸附氯的实验研究%Experimental Research on Adsorption of Chlorine from Molasses Solution with Ion Exchange

    Institute of Scientific and Technical Information of China (English)

    邹晓勇; 陈民仁

    2015-01-01

    糖蜜是制糖业的副产品,可做为软锰矿生产电解锰的还原剂,但是糖蜜中含有的氯离子限制了其应用。采用静态和动态实验方法,选用大孔阴离子树脂对糖蜜中的氯离子进行了吸附实验研究,结果表明,树脂对Cl-具有良好的吸附性能和解吸效果,在氯离子含量为12.2 g/L的条件下,对氯的吸附容量为121 mg/g湿树脂,氯离子的解吸剂为1.0 mol/L的稀硫酸,解吸率可达95.4%。经过工业化试验,糖蜜中氯离子脱除率为84%。%Molasses is a by-product of the sugar industry, it could be used as reducing agent in production of electrolytic manganese by pyrolusite, but the chloride ion has limited its application. Using static and dynamic experimental methods, macroporous anion resin was carried out as experimental study on adsorption of chloride ion in molasses. The results showed that the resin had good adsorption and desorption effect on Cl-, under the condition of the chloride ion content of 12. 2 g/L, the adsorption capacity of the resin could reach 121 mg/g wet resin, the loaded resin could be eluted with 1. 0 mol/L dilute sulfuric acid, the elution rate was 95. 4%. After the industrial test, molasses chloride removal rate reached 84%.

  15. Study on the identification of organic and common anions in the pyrohydrolysis distillate of mixed uranium-plutonium carbide for the interference free determination of chlorine and fluorine by ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Jeyakumar, Subbiah; Mishra, Vivekchandra Guruprasad; Das, Mrinal Kanti; Raut, Vaibhavi Vishwajeet; Sawant, Ramesh Mahadeo [Bhabha Atomic Research Centre, Mumbai (India). Radioanalytical Chemistry Div.; Ramakumar, Karanam Lakshminarayana [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry and Isotope Group

    2014-07-01

    Identification of various soluble organic acids formed during the pyrohydrolysis of uranium-plutonium mixed carbide [(U,Pu)C] was carried out using ion chromatography. This has significant importance as the soluble organic acids can cause severe interferences during the ion chromatography separation and determination of Cl{sup -} and F{sup -} in the pyrohydrolysis distillate of (U,Pu)C. Determination of Cl and F is important in the chemical quality control of nuclear materials as these two elements can cause corrosion and hence, their concentrations in all nuclear materials are restricted to certain specified values. Since the pyrohydrolysis distillates contain both inorganic and organic acid anions, for the sake of separating and identifying organic acid anions from the common inorganic anions, three independent isocratic elutions using varying concentrations of NaOH eluent were employed for the separation of weakly, moderately and strongly retained anions. It was observed that pyrohydrolysis of (U,Pu)C also produced soluble organic acids as in the case of nitric acid dissolution of UC. The present investigation revealed the presence of formic, acetic, propionic, butyric, oxalic acid anions in the pyrohydrolysis distillate of (U,Pu)C in trace or ultra-trace concentrations. The presence of each organic acid identified in the chromatogram was confirmed with spike addition as well as by separating them by capillary electrophoresis method. The presence of lower aliphatic acids viz. formic and acetic acids was reconfirmed by carrying out an independent separation with tetraborate eluent. It is suggested that nitric acid being formed during pyrohydrolysis could be responsible for the formation of organic acids. Based on the findings, an ion chromatography separation method has been proposed for the interference-free determination of chloride and fluoride in pyrohydrolysis distillate of (U,Pu)C. (orig.)

  16. Study on the identification of organic and common anions in the pyrohydrolysis distillate of mixed uranium-plutonium carbide for the interference free determination of chlorine and fluorine by ion chromatography

    International Nuclear Information System (INIS)

    Identification of various soluble organic acids formed during the pyrohydrolysis of uranium-plutonium mixed carbide [(U,Pu)C] was carried out using ion chromatography. This has significant importance as the soluble organic acids can cause severe interferences during the ion chromatography separation and determination of Cl- and F- in the pyrohydrolysis distillate of (U,Pu)C. Determination of Cl and F is important in the chemical quality control of nuclear materials as these two elements can cause corrosion and hence, their concentrations in all nuclear materials are restricted to certain specified values. Since the pyrohydrolysis distillates contain both inorganic and organic acid anions, for the sake of separating and identifying organic acid anions from the common inorganic anions, three independent isocratic elutions using varying concentrations of NaOH eluent were employed for the separation of weakly, moderately and strongly retained anions. It was observed that pyrohydrolysis of (U,Pu)C also produced soluble organic acids as in the case of nitric acid dissolution of UC. The present investigation revealed the presence of formic, acetic, propionic, butyric, oxalic acid anions in the pyrohydrolysis distillate of (U,Pu)C in trace or ultra-trace concentrations. The presence of each organic acid identified in the chromatogram was confirmed with spike addition as well as by separating them by capillary electrophoresis method. The presence of lower aliphatic acids viz. formic and acetic acids was reconfirmed by carrying out an independent separation with tetraborate eluent. It is suggested that nitric acid being formed during pyrohydrolysis could be responsible for the formation of organic acids. Based on the findings, an ion chromatography separation method has been proposed for the interference-free determination of chloride and fluoride in pyrohydrolysis distillate of (U,Pu)C. (orig.)

  17. 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 ...

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

    OpenAIRE

    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 formation of less desirable side-products. For example, mixtures of chlorinated C1 and C2 hydrocarbons are still formed as by-products in industrial processes such as the production of vinyl chlor...

  19. Formation of Chloroform and Other Chlorinated Byproducts by the Chlorination of Antibacterial Products

    OpenAIRE

    Fiss, Edward Matthew

    2006-01-01

    Triclosan is a widely used antibacterial agent found in many personal hygiene products. While it has been established that pure triclosan and free chlorine readily react, interactions between triclosan-containing products and free chlorine have not previously been analyzed. Sixteen double-blinded solutions including both triclosan-containing (1.14-3.12 mg triclosan/g product) and triclosan-free products were contacted with free chlorine. Products detected included (chlorophenoxy)phenols, ...

  20. Chlorine demand studies: a need for optimisation of chlorine doses for biofouling control

    International Nuclear Information System (INIS)

    Studies on chlorine demand, chlorine decay, rate of HOBr formation and speciation of chlorine residuals of cooling water from Madras Atomic Power Station (MAPS) were carried out. April to September was found to be a high demand period. The rate of reaction is faster and also initial demand is relatively high for this seawater as compared to other sea areas. Decay occurs in two phases, the first being instantaneous and the second being very slow. (author). 9 refs., 1 fig

  1. 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.

  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. Radiolytic removal of trihalomethane in chlorinated seawater

    International Nuclear Information System (INIS)

    Biofouling is one of the major operational problems in seawater cooling systems. It is controlled by application of chlorine based biocides in the range of 0.5-2.0 mg L-1. The bromide in seawater reacts with the added chlorine and forms hypobromous acid. The brominated residual biocides react with natural organic matter present in the seawater, resulting in the formation of trihalomethanes (THM) such as bromoform (CHBr3), dibromochloromethane (CHBr2Cl) bromodichloromethane (CHBrCl2). Though THMs represent a small fraction of the added chlorine, they are relatively more persistent than residual chlorine, and hence pose a potential hazard to marine life because of their reported mutagenicity. There have been few reports on removal of THMs from chlorinated seawater. In this work, the efficacy of gamma irradiation technique for the removal of THMs from chlorine-dosed seawater was investigated. Experiments were carried out using seawater collected from Kalpakkam. Irradiation study was conducted in chlorinated (1, 3, and 5 mg L-1 of Cl2) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation using a 60Co Gamma Chamber 5000. Bromoform showed a faster rate of degradation as compared to other halocarbons like bromodichloromethane and dibromochloromethane. This shows the change in total THM concentration with variation in the radiation dose and initial Cl2 dosing. When the percentage degradation of all the three trihalomethane species was compared with applied doses, it was found that the maximum reduction occurred at a dose of 2.5 kGy. The reduction was almost similar for all the three doses (1, 3, 5 ppm of Cl2) used for chlorination. With a further increase in radiation dose to 5.0 kGy, a slight increase in reduction was observed

  4. 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

  5. Effects of chlorine and chlorine dioxide on human rotavirus infectivity and genome stability.

    Science.gov (United States)

    Xue, Bin; Jin, Min; Yang, Dong; Guo, Xuan; Chen, Zhaoli; Shen, Zhiqiang; Wang, Xinwei; Qiu, Zhigang; Wang, Jingfeng; Zhang, Bin; Li, Junwen

    2013-06-15

    Despite the health risks posed by waterborne human rotavirus (HRV), little information is available concerning the effectiveness of chlorine or chlorine dioxide (ClO2), two common disinfectants of public water sources, against HRV and their effects on its genome remain poorly understood. This study investigated the effects of chlorine and ClO2 on purified HRV by using cell culture and RT-PCR to assess virus infectivity and genetic integrity, respectively. The disinfection efficacy of ClO2 was found to be higher than that of chlorine. According to the efficiency factor Hom model, Ct value (mg/L min) ranges required for a 4-log reduction of HRV at 20 °C by chlorine and ClO2 were 5.55-5.59 and 1.21-2.47 mg/L min, respectively. Detection of the 11 HRV genome segments revealed that damage to the 1227-2354 bp of the VP4 gene was associated with the disappearance of viral infectivity by chlorine. However, no complete accordance between culturing and RT-PCR assays was observed after treatment of HRV with ClO2. These results collectively indicate that the current practice of chlorine disinfection may be inadequate to manage the risk of waterborne HRV infection, and offer the potential to monitor the infectivity of HRV adapting PCR-based protocols in chlorine disinfection. PMID:23591108

  6. 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.

  7. 3.6. Chlorination of alumina containing waste products

    International Nuclear Information System (INIS)

    Chlorination of alumina containing waste products is considered in this article. Based on conducted studies following optimal conditions of chlorination of alumina containing waste products with reducer - coal were found: temperature - 750-850 deg C, chlorination duration -1-1,5 hours, quantity of reducer - 30% and size of particles - 0,1 mm. Based on conducted studies following optimal conditions of chlorination of alumina containing waste products with reducer - natural gas were found: temperature - 650-750 deg C, chlorination duration - 2 hours, chlorine to methane ratio is 4:1 and size of particles - 0,2-0,3 mm.

  8. Chlorination of UO2, PuO2, and rare-earth oxides using ZrCl4

    International Nuclear Information System (INIS)

    A new chlorination method using ZrCl4, which has a high reactivity with oxygen, has been investigated for more efficient oxide treatment. After actinide oxides are chlorinated and dissolved in a molten salt bath, actinide metals can be selectively collected using the electrorefining process. This process is well suited for pyrochemical reprocessing of metallic fuels. In LiCl-KCI eutectic melts, rare-earth oxides (Y2O3, La2O3, CeO2, and Nd2O3) and actinide oxides (UO2 and PuO2) were chlorinated by adding ZrCl4. As a result, rare-earth and actinide elements were dissolved into the salt as trivalent ions and ZrO2 was precipitated. When an excess of ZrCI4 was added, oxides in powder form were completely chlorinated in five hours. It was demonstrated that the ZrCI4 chlorination method, free from corrosive gas such as chlorine, was very simple and useful. (author)

  9. Phosphate valorization by dry chlorination route

    Directory of Open Access Journals (Sweden)

    Kanari N.

    2016-01-01

    Full Text Available This work deals with the extraction of phosphorus chlorinated compounds from phosphate materials using chlorination with gaseous chlorine. An industrial sample of dicalcium phosphate dihydrate, after transformation into calcium pyrophosphate (Ca2P2O7, is subjected to reactions with Cl2+CO+N2 and Cl2+C+N2 at temperatures ranging from 625 to 950°C using boat experiments. Gathering results of the thermodynamic predictions and TG/DT analysis with those of SEM and XRD examinations of the chlorinated residues allowed the interpretation of phenomena and reactions mechanism occurring during the calcium pyrophosphate carbochlorination. Reaction rate of Ca2P2O7 by Cl2+CO+N2 at 950°C is slowed down due to the formation of a CaCl2 liquid layer acting as a barrier for the diffusion of the reactive gases and further reaction progress. While, the carbochlorination with Cl2+C+N2 led to almost full chlorination of Ca2P2O7 at 750°C and the process proceeds with an apparent activation energy of about 104 kJ/mol between 625 and 750°C. Carbochlorination technique can be considered as an alternative and selective route for the valorization of low grade phosphates and for the phosphorus extraction from its bearing materials.

  10. Accumulation of chlorinated benzenes in earthworms

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, W.N. [Patuxent Wildlife Research Center, Laurel, MD (United States)

    1996-12-31

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. They probably entered the water as leachates from chemical waste dumps and as effluents from manufacturing. Hexachlorobenzene and pentachlorobenzene are commonly present in Herring gull (Larus argentatus) eggs from the Great Lakes, and some of the isomers of trichlorobenzene and tetrachlorobenzene are occasionally detected at low concentrations. Hexachlorobenzene, which was formerly used as a fungicide, has been the most thoroughly studied chlorinated benzene, and has been detected in many species. Its use as a fungicide in the United States was canceled in 1984. Since about 1975 hexachlorobenzene has been formed mainly in the production of chlorinated solvents. It is highly persistent in the environment and some species are poisoned by hexachlorobenzene at very low chronic dietary exposures. As little as 1 ppm in the diet of mink (Mustela vison) reduced the birth weights of young, and 5 ppm in the diet of Japanese quail (Coturnix coturnix japonica) caused slight liver damage. This paper describes a long-term (26 wk) experiment relating the concentrations of chlorinated benzenes in earthworms to length of exposure and three 8 wk experiments relating concentration to the concentration in soil the soil organic matter content, and the degree of chlorination. 20 refs., 3 figs., 1 tab.

  11. Supported metal nanoparticles for the remediation of chlorinated hydrocarbons

    Science.gov (United States)

    Schrick, Bettina

    Zero valent iron filings are currently being used in pilot scale field studies to dehalogenate toxic chlorinated hydrocarbons from contaminated surface- and groundwater. Iron filings reduce trichloroethylene (TCE), a model contaminant, via two interconnected degradation pathways: (a) reductive beta-elimination and (b) sequential hydrogenolysis, in which each chlorine atom is sequentially replaced by hydrogen. For the latter pathway, problems arise because the dehalogenation rate decreases as the number of chlorine atoms in the molecule decreases. Therefore, some of the products formed, such as vinyl chloride (VC), are more toxic than the parent compound (TCE), and are only slowly reduced by iron. To improve the rate, cost and technique of remediation for chlorinated hydrocarbons, zero valent nickel-iron (Ni-Fe) nanoparticles have been developed. To elucidate the dehalogenation reaction and particularly the product distributions from a mechanistic standpoint, the roles that nickel and iron play in the dehalogenation of TCE were studied. On the bimetallic particles, the reaction occurs by nickel-catalyzed hydrodechlorination. As the iron actively corrodes, the cathodically protected nickel surface chemisorbs hydrogen ions, and TCE adsorbed to the Ni surface is thus hydrogenated. This reaction competes kinetically with the evolution of molecular hydrogen. Hydrogenolysis of the C-Cl bond results in the formation of linear, as well as branched saturated and unsaturated hydrocarbons. Dispersing the nanometals onto high surface area supports, such as hydrophilic carbon or polyacrylic acid (PAA), provides a delivery vehicle for the reactive nanoparticles. The support acts as a nanometal carrier, and may also help preconcentrate the toxins, and provide a conductive pathway for electron transfer. In general, supports are expected to stabilize the nanoparticles and give an increased surface to volume ratio. The carbon- and PAA-supported nanometals form a permanent suspension

  12. Evaluation on joint toxicity of chlorinated anilines and cadmium to Photobacterium phosphoreum and QSAR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hao, E-mail: realking163@163.com [School of Life and Chemistry, Jiangsu Second Normal University, Nanjing, Jiangsu 210013 (China); Wang, Chao; Shi, Jiaqi [State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu 210023 (China); Chen, Lei [School of Life and Chemistry, Jiangsu Second Normal University, Nanjing, Jiangsu 210013 (China)

    2014-08-30

    Highlights: • Cd has different effects on joint toxicity when in different concentrations. • The toxicity of most binary mixtures decreases when Cd concentration rises. • Different QSAR models are developed to predict the joint toxicity. • Descriptors in QSARs can help to elucidate the joint toxicity mechanism. • Van der Waals’ force or complexation may reduce the toxicity of mixtures. - Abstract: The individual IC{sub 50} (the concentrations causing a 50% inhibition of bioluminescence after 15 min exposure) of cadmium ion (Cd) and nine chlorinated anilines to Photobacterium phosphoreum (P. phosphoreum) were determined. In order to evaluate the combined effects of the nine chlorinated anilines and Cd, the toxicities of chlorinated anilines combined with different concentrations of Cd were determined, respectively. The results showed that the number of chlorinated anilines manifesting synergy with Cd decreased with the increasing Cd concentration, and the number manifesting antagonism decreased firstly and then increased. The joint toxicity of mixtures at low Cd concentration was weaker than that of most binary mixtures when combined with Cd at medium and high concentrations as indicated by TU{sub Total}. QSAR analysis showed that the single toxicity of chlorinated anilines was related to the energy of the lowest unoccupied molecular orbital (E{sub LUMO}). When combined with different concentrations of Cd, the toxicity was related to the energy difference (E{sub HOMO} − E{sub LUMO}) with different coefficients. Van der Waals’ force or the complexation between chlorinated anilines and Cd had an impact on the toxicity of combined systems, which could account for QSAR models with different physico-chemical descriptors.

  13. 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)

  14. 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...

  15. Quantification, qualification, and microbial killing efficiencies of antimicrobial chlorine-based substances produced by iontophoresis.

    OpenAIRE

    Davis, C P; Shirtliff, M.E.; Trieff, N. M.; Hoskins, S L; Warren, M M

    1994-01-01

    The dependence of microbial killing on chloride ions present in solutions undergoing iontophoresis is addressed. A 400-microA current was applied to vials containing synthetic urine or saline, and the production of chlorine-based substances (CBSs) was detected by the N,N-diethyl-p-phenylene diamine colorimetric method. It was found that as the time of current application increased, the total concentration of CBSs also increased. The iontophoretic current converted (through oxidation) chloride...

  16. Separation of niobium from ferroniobium by chlorination

    International Nuclear Information System (INIS)

    Separation of niobium from ferroniobium by chlorine metallurgy were investigated. The chlorination of ferroniobium by chlorine gas was carried out under several thermodynamic conditions and the effective conditions were determined. Preliminary separation of niobium pentachloride from ferric chloride is possible by selective condensation with temperature gradient techniques. Selective reduction of ferric chloride to ferrous chloride by iron powder was done to separate niobium pentachloride by their volatility difference. Separation of niobium pentachloride from ferric chloride using organic solvent was tested. The niobium pentachloride with high purity could be separated effectively from ferroniobium chlorides by selective reduction of ferric chloride and selective dissolution of niobium pentachloride in organic solvent. A new dry process which has the possibility of industrial application is presented. (Author

  17. 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

  18. Chlorine dioxine DBPs (disinfection by-products in drinking water

    Directory of Open Access Journals (Sweden)

    C. Lasagna

    2013-01-01

    Full Text Available Since the 1970s it has been well known that, though water for human consumption is generally disinfected before being distributed along the network, the use of chemicals results in the formation of many different Disinfection By-Products (DBPs. In the case of chlorine dioxide, the most important and represented DBPs are chlorite and chlorate: after an introduction concerning the current Italian regulation on this subject, in the experimental part the results of a 7-year minitoring campaign, concerning water of different origin collected from taps in various Italian regions, are shown. The analytical technique used for the determination of chlorite and chlorate was Ion Chromatography. The result obtained are finally discussed.

  19. Feasibility study of self-lubrication by chlorine implantation

    Science.gov (United States)

    Akhajdenung, T.; Aizawa, T.; Yoshitake, M.; Mitsuo, A.

    2003-05-01

    Implantation of chlorine into titanium nitride (TiN) coating on the high-speed steel substrate has succeeded in significant reduction of wear rate and friction coefficient for original TiN under dry wear condition. Through precise investigation on the surface reaction in the wear track, in situ formation of oxygen-deficient titanium oxides was found to play a role as a lubricious oxide. In the present paper, this self-lubrication mechanism is further investigated for various wearing conditions. For wide range of sliding speed and normal load in the wear map, the wear volume of a counter material is actually reduced with comparison to the un-implanted TiN. Effect of the ion implantation dose on this self-lubrication mechanism is also studied for practical use. Some comments are made on further application of this self-lubrication to manufacturing.

  20. Feasibility study of self-lubrication by chlorine implantation

    International Nuclear Information System (INIS)

    Implantation of chlorine into titanium nitride (TiN) coating on the high-speed steel substrate has succeeded in significant reduction of wear rate and friction coefficient for original TiN under dry wear condition. Through precise investigation on the surface reaction in the wear track, in situ formation of oxygen-deficient titanium oxides was found to play a role as a lubricious oxide. In the present paper, this self-lubrication mechanism is further investigated for various wearing conditions. For wide range of sliding speed and normal load in the wear map, the wear volume of a counter material is actually reduced with comparison to the un-implanted TiN. Effect of the ion implantation dose on this self-lubrication mechanism is also studied for practical use. Some comments are made on further application of this self-lubrication to manufacturing

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  2. 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

  3. Scattering and recoiling imaging spectrometry (SARIS) study of chlorine chemisorption on Ni(1 1 0)

    International Nuclear Information System (INIS)

    The clean and chlorine chemisorbed Ni(1 1 0) surface has been investigated by scattering and recoiling imaging spectrometry (SARIS). Rare gas ion beams at 4 keV were scattered at different incident (α) and exit (β) angles along different azimuthal directions of the surface. The LEED pattern changed from a sharp (1x1) to a weak (3x1) after exposure to Cl2. The He+ images from the Cl/Ni surface exhibited very little differences compared to those of the clean surface. This is due to the high penetration depth of the He+ ions, which results in low surface sensitivity. The images obtained from the Cl/Ni surface with the heavier ions exhibited obvious changes due to their low penetration depths, which facilitates high surface sensitivity. Scattering and Recoiling Imaging Code (SARIC) simulations were carried out in order to interpret the perturbations induced by the chlorine adatoms. Different chemisorption sites for chlorine were tested. The results of the experiments and simulations agree that Cl atoms are chemisorbed in the short-bridge sites above the [1 1-bar 0] rows

  4. 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)

  5. 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

  6. Electronic properties, doping and defects in chlorinated silicon nanocrystals

    OpenAIRE

    de Carvalho, A.; Öberg, S; Rayson, M. J.; Briddon, P. R.

    2011-01-01

    Silicon nanocrystals with diameters between 1 and 3 nm and surfaces passivated by chlorine or a mixture of chlorine and hydrogen were modeled using density functional theory, and their properties compared with those of fully hydrogenated nanocrystals. It is found that fully and partially chlorinated nanocrystals are stable, and have higher electron affinity, higher ionization energy and lower optical absorption energy threshold. As the hydrogenated silicon nanocrystals, chlorinated silicon na...

  7. 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 ...

  8. Immunofluorescence and morphology of Giardia lamblia cysts exposed to chlorine.

    OpenAIRE

    Sauch, J F; Berman, D

    1991-01-01

    Giardia cyst-like objects detected by immunofluorescence in chlorinated water samples often cannot be positively identified by their morphological appearance. To determine the effect of chlorine on cyst immunofluorescence and morphology, Giardia lamblia cysts were exposed to chlorine for 48 h. The majority of cysts exposed to chlorine concentrations of 1 to 11 mg/liter at 5 and 15 degrees C lost their internal morphological characteristics necessary for identification, but most of them were s...

  9. 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.

  10. 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

  11. Electrokinetic-enhanced bioaugmentation for remediation of chlorinated solvents contaminated clay.

    Science.gov (United States)

    Mao, Xuhui; Wang, James; Ciblak, Ali; Cox, Evan E; Riis, Charlotte; Terkelsen, Mads; Gent, David B; Alshawabkeh, Akram N

    2012-04-30

    Successful bioremediation of contaminated soils is controlled by the ability to deliver bioremediation additives, such as bacteria and/or nutrients, to the contaminated zone. Because hydraulic advection is not practical for delivery in clays, electrokinetic (EK) injection is an alternative for efficient and uniform delivery of bioremediation additive into low-permeability soil and heterogeneous deposits. EK-enhanced bioaugmentation for remediation of clays contaminated with chlorinated solvents is evaluated. Dehalococcoides (Dhc) bacterial strain and lactate ions are uniformly injected in contaminated clay and complete dechlorination of chlorinated ethene is observed in laboratory experiments. The injected bacteria can survive, grow, and promote effective dechlorination under EK conditions and after EK application. The distribution of Dhc within the clay suggests that electrokinetic transport of Dhc is primarily driven by electroosmosis. In addition to biodegradation due to bioaugmentation of Dhc, an EK-driven transport of chlorinated ethenes is observed in the clay, which accelerates cleanup of chlorinated ethenes from the anode side. Compared with conventional advection-based delivery, EK injection is significantly more effective for establishing microbial reductive dechlorination capacity in low-permeability soils. PMID:22365139

  12. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl− led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins

  13. Identification of chlorinated oligomers formed during anodic oxidation of phenol in the presence of chloride

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linxi; Campo, Pablo; Kupferle, Margaret J., E-mail: margaret.kupferle@uc.edu

    2015-02-11

    Graphical abstract: - Highlights: • By-products from anodic oxidation of phenol in the presence of chloride are investigated. • Chlorinated oligomer formation is demonstrated by LC-QTOF-MS. • They have structures similar to triclosan and polychlorinated dibenzo-p-dioxins. - Abstract: Chlorinated oligomer intermediates formed during the anodic electrochemical oxidation of phenol with a boron-doped diamond electrode were studied at two different concentrations of chloride (5 mM and 50 mM). Under the same ionic strength, with sodium sulfate being the make-up ion, a 10-fold increase in Cl{sup −} led to removal rates 10.8, 1.5, and 1.4 times higher for phenol, TOC, and COD, respectively. Mono-, di- and trichlorophenols resulting from electrophilic substitution were the identified by-products. Nevertheless, discrepancies between theoretical and measured TOC values along with gaps in the mass balance of chlorine-containing species indicated the formation of unaccounted-for chlorinated by-products. Accurate mass measurements by liquid chromatography quadrupole time-of-flight mass spectrometry and MS-MS fragmentation spectra showed that additional compounds formed were dimers and trimers of phenol with structures similar to triclosan and polychlorinated dibenzo-p-dioxins.

  14. 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....

  15. 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...

  16. 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.

  17. 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

  18. 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...

  19. Reaction products of aquatic humic substances with chlorine.

    OpenAIRE

    Johnson, J D; Christman, R F; Norwood, D L; Millington, D S

    1982-01-01

    A major concern of the chlorination of aquatic humic materials is the ubiquitous production of trihalomethanes. A large number of other chlorinated organic compounds, however, have been shown to be formed by chlorine's reaction with humic substances. In this study, humic material was concentrated from a coastal North Carolina lake and chlorinated at a chlorine to carbon mole ratio of 1.5 at pH 12. A high pH was necessary for complete dissolution of the humic material and for production of ade...

  20. 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

  1. 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

  2. High-performance Ti/Sb-SnO(2)/Pb(3)O(4) electrodes for chlorine evolution: preparation and characteristics.

    Science.gov (United States)

    Shao, Dan; Yan, Wei; Cao, Lu; Li, Xiaoliang; Xu, Hao

    2014-02-28

    Chlorine evolution via electrochemical approach has wide application prospects in drinking water disinfection and wastewater treatment fields. Dimensional stable anodes used for chlorine evolution should have high stability and adequate chlorine evolution efficiency. Thus a novel and cost-effective Ti/Sb-SnO(2)/Pb(3)O(4)electrode was developed. The physicochemical and electrochemical properties as well as the chlorine evolution performances of the electrodes were investigated. The electrocatalytic activity and deactivation course of the electrodes were also explored. Results showed that this novel electrode had strong chlorine evolution ability with high current efficiency ranging from 87.3% to 93.4% depending on the operational conditions. The accelerated service life of Ti/Sb-SnO(2)/Pb(3)O(4) electrode could reach 180 h at a current density of 10,000 A m(-2) in 0.5 molL(-1) H(2)SO(4). During the electrolysis process, it was found that the conversion of Pb(3)O(4) into β-PbO(2) happened gradually on the electrode surface, which not only inhibited the leakage of hazardous Pb(2+) ion but also increased the anti-corrosion capacity of the electrode effectively. PMID:24462893

  3. Chromatographic study of gamma-ray irradiated degradation of chlorinated hydrocarbon in water

    International Nuclear Information System (INIS)

    Degradation of chlorinated hydrocarbon in gamma ray irradiation was examined in order to get information on treatment of groundwater. Water chloroform was sealed into a vial irradiated with gamma ray. Both gas chromatography and ion chromatography were applied for determination of degradation products. Carbon dioxide, carbon monoxide, methane, ethane and chloride ion were detected in the irradiated system. Effect of radiation dose on the gamma ray induced chloroform degradation was investigated. The elimination of chloride ion and the degradation of chloroform were promoted by gamma irradiation in a dose-dependent manner. The G(CHCl3), which was defined as the number of degraded chloroform molecules when absorbed 100eV, was inferred to be 3.1. The degradation mechanism of chloroform irradiated with gamma ray seemed to involve that chloroform reacted with electron from radiolysis of water and the elimination of chloride ion occurred. (author)

  4. 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)

  5. 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)

  6. 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

  7. 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.

  8. Chlorine-Free Red-Burning Pyrotechnics.

    Science.gov (United States)

    Sabatini, Jesse J; Koch, Ernst-Christian; Poret, Jay C; Moretti, Jared D; Harbol, Seth M

    2015-09-01

    The development of a red, chlorine-free pyrotechnic illuminant of high luminosity and spectral purity was investigated. Red-light emission based solely on transient SrOH(g) has been achieved by using either 5-amino-1H-tetrazole or hexamine to deoxidize the combustion flame of a Mg/Sr(NO3 )2 /Epon-binder composition and reduce the amount of both condensed and gaseous SrO, which emits undesirable orange-red light. The new formulations were found to possess high thermal onset temperatures. Avoiding chlorine in these formulations eliminates the risk of the formation of PCBs, PCDDs, and PCDFs. This finding, hence, will have a great impact on both military pyrotechnics and commercial firework sectors. PMID:26333055

  9. Spectrographic determination of chlorine and fluorine

    International Nuclear Information System (INIS)

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

  10. 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

  11. Stability and effectiveness of chlorine disinfectants in water distribution systems.

    Science.gov (United States)

    Olivieri, V P; Snead, M C; Krusé, C W; Kawata, K

    1986-11-01

    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 pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min. PMID:3028767

  12. 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.).

  13. Chlorine requirement for Japanese laying quails

    OpenAIRE

    Fernando Guilherme Perazzo Costa; Jalceyr Pessoa Figueiredo Júnior; Denise Fontana Figueiredo Lima; Cláudia de Castro Goulart; José Humberto Vilar da Silva; Matheus Ramalho de Lima; Sarah Gomes Pinheiro; Valéria Pereira Rodrigues

    2012-01-01

    The objective of this study was to determine the chlorine nutritional requirement of Japanese Quails during the laying phase, based on performance and egg quality parameters. A total of 240 Japanese quails were distributed according to a randomized block design, with five treatments and six replicates, with 8 birds each. The experiment lasted 84 days, divided in four cycles of 21 days each. Treatments consisted of a basal diet formulated to meet the nutritional requirements, except for chlori...

  14. Radioimmunoassay for chlorinated dibenzo-p-dioxins

    International Nuclear Information System (INIS)

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

  15. 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

  16. 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

  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(1.000: 87-90

  18. Electric plasma discharge combustion synthesis of chlorine dioxide

    International Nuclear Information System (INIS)

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

  19. 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...

  20. Some kinetics aspects of chlorine-solids reactions

    OpenAIRE

    Kanari, N.; Mishra, D.; Mochón, J.; Verdeja, L. F.; Diot, F.; Allain, E.

    2011-01-01

    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 (...

  1. 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...

  2. Palau’chlor: A Practical and Reactive Chlorinating Reagent

    OpenAIRE

    Rodriguez, Rodrigo A.; Pan, Chung-Mao; Yabe, Yuki; Kawamata, Yu; Eastgate, Martin D.; Baran, Phil S.

    2014-01-01

    Unlike its other halogen atom siblings, the utility of chlorinated arenes and (hetero)arenes are twofold: they are useful in tuning electronic structure as well as acting as points for diversification via cross-coupling. Herein we report the invention of a new guanidine-based chlorinating reagent, CBMG or “Palau’chlor”, inspired by a key chlorospirocyclization en route to pyrrole imidazole alkaloids. This direct, mild, operationally simple, and safe chlorinating method is compatible with a ra...

  3. 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...

  4. 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...

  5. Water splitting processes of the iron-chlorine family

    International Nuclear Information System (INIS)

    Multi-step processes for thermal water splitting comprise individual chemical reactions which, as far as the iron-chlorine family is concerned, may be generalized: hydrolysis, chlorination, dechlorination, reduction, regeneration of chlorinating agent. These categories comprise series of chemical equations which can be combined to water splitting cycles in different configurations. A systematic estimation of the chemical equations of the five categories is given instead of treating several hundred water-splitting processes of the iron-chlorine family. The individual chemical equations are estimated from published data, by laboratory experiments, and by operating conditions of technical processes. (author)

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

    OpenAIRE

    Zoeteman, B C; Hrubec, J.; De Greef, E; Kool, H J

    1982-01-01

    A retrospective epidemiological study in The Netherlands showed a statistical association between chlorination by-products in drinking water and cancer of the esophagus and stomach for males. A pilot-plant study with alternative disinfectants was carried out with stored water of the Rivers Rhine and Meuse. It was demonstrated that the increase of direct acting mutagens after treatment with chlorine dioxide is similar to the effect of chlorination. Ozonation of Rhine water reduced the mutageni...

  7. Proof-of-Concept Experiments for Negative Ion Driver Beams for Heavy Ion Fusion

    International Nuclear Information System (INIS)

    Negative halogen ion beams have recently been proposed as heavy ion fusion drivers. They would avoid the problem of electron accumulation in positive ion beams, and could be efficiently photo-detached to neutrals if desired. Initial experiments using chlorine produced a current density of 45 mA/cm2 of 99.5% atomic negative Cl with an e/Cl- ratio as low as 7:1 and good emittance

  8. MECHANISM OF FUSARIUM TRICINCTUM (CORDA SACC. SPORE INACTIVATION BY CHLORINE DIOXIDE

    Directory of Open Access Journals (Sweden)

    Zhao Chen

    2015-06-01

    Full Text Available The mechanism of Fusarium tricinctum (Corda Sacc. spore inactivation by chlorine dioxide (ClO2 was investigated. During F. tricinctum spore inactivation by ClO2, protein, DNA, and metal ion leakage, enzyme activity, and cell ultrastructure were examined. Protein and DNA leakages were not detected, while there were metal ion leakages of K+, Ca2+, and Mg2+, which were well-correlated with the inactivation rate. The enzyme activities of glucose-6-phosphate dehydrogenase, citrate synthase, and phosphofructokinase were inhibited and were also well-correlated with the inactivation rate. Electron micrographs showed the ultrastructural modifications of spores and demonstrated that spores were heavily distorted and collapsed from their regular structure. Spore surface damage and disruption in inner components was also severe. The metal ion leakage, the inhibition of enzyme activities, and the damage of spore structure were significant in F. tricinctum spore inactivation by ClO2.

  9. 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

  10. The treatment of iodine and chlorine chemistry in the risk assessment of deep radioactive waste disposal

    International Nuclear Information System (INIS)

    The predicted contribution from 129I, 131I and 36Cl to the radiological risk from a radioactive waste repository may be enhanced by the assumption of limited retardation in the near field and geosphere. However, migration of these radionuclides may be affected by their chemical speciation and retarded by a range of sorption processes. The chemical behaviour of iodine and chlorine is determined emphasizing i) aqueous speciations, ii) sorption onto inorganic substrates, and iii) the role of organic matter and microbes. Recommendations to enhance the methodology include i) consideration of aqueous speciation of iodine, both metal and organic complexes, ii) mechanistic simulation of iodine sorption by ion exchange and electrostatic/covalent adsorption, iii) simulation of enzymatically enhanced sorption of iodine and chlorine onto organic substrates, iv) enhancement of HMIP Kd databases to include iodine and chlorine data for the geosphere and biosphere. A well defined programme of additional data collection, modelling studies and experimental investigations is recommended to achieve these enhancements. (author)

  11. Eu(III) complex luminescence behavior upon chlorine substitution in the 1,10-phenanthroline ligand: A theoretical and experimental study

    International Nuclear Information System (INIS)

    Graphical abstract: In this work, it were performed computational design and synthesis of a new luminescent Eu(III) complex with the usual 1,10-phenanthroline ligand substituted in the 4 and 7 positions by chlorine atoms, which one has shown a higher luminescent output than that of the non-substituted analogous complex. Research highlights: → Eu-complexes with non-chlorinated or chlorinated phenanthroline were synthesized. → Molecular structures for complexes using the Sparkle and DFT methods were obtained. → The chlorinated complex shown higher luminescence intensities. - Abstract: In this work, it were performed computational design and synthesis of a new luminescent Eu(III) complex with the usual 1,10-phenanthroline ligand substituted in the 4 and 7 positions by chlorine atoms, which one has shown a higher luminescent output than that of the non-substituted analogous complex. The molecular structures for all complexes using the Sparkle and DFT methods were obtained, such as their coordination bond distances with values in a typical range. Analyzing the direct Eu(III) ion excitation for the phenCl complex, all of them are red shifted in comparison to the one of the phen complex suggesting that the ion environment is more polarizable in the first case, this corroborate with results obtained for intensities and R02 parameters.

  12. Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Beverskog, B. [Studsvik Material AB, Nykoeping (Sweden); Puigdomenech, I. [Studsvik Eco and Safety AB, Nykoeping (Sweden)

    1998-04-01

    Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10{sup -4} and 10{sup -6} molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl{sub 2} {center_dot} 3Cu(OH){sub 2} is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl{sub 2}{sup -} predominates at all temperatures at [Cl(aq)]{sub tot}=0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)]{sub tot}=10{sup -6} and [Cl(aq)]{sub tot}=0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl{sub 3}{sup 2-} predominates at 5-25 and 100 deg C, while CuCl{sub 2}{sup -} predominates at 50-80 deg C at [Cl(aq)]{sub tot=}1-5 molal. A copper concentration of 10{sup -4} molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pH{sub {Tau}}<9.5 and 1.5 molal chloride concentration. According to our calculations the copper canisters in the deep nuclear waste repository should not corrode at the copper concentration of 10{sup -6} molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to

  13. Pourbaix diagrams for the system copper-chlorine at 5-100 deg C

    International Nuclear Information System (INIS)

    Pourbaix diagrams for the copper-chlorine system in the temperature interval 5-100 deg C have been revised. Predominance diagrams for dissolved copper containing species have also been calculated. Two different total concentrations of each dissolved element, 10-4 and 10-6 molal for copper and 0.2 and 1.5 molal for chlorine have been used in the calculations. Chloride is the predominating chlorine species in aqueous solutions. Presence of chloride increases the corrosion regions of copper at the expense of the immunity and passivity regions in the Pourbaix diagrams. CuCl2 · 3Cu(OH)2 is the only copper-chloride solid phase that forms at the concentrations of chlorine studied. However, its stability area decreases with increasing temperature. The ion CuCl2- predominates at all temperatures at [Cl(aq)]tot=0.2 molal and this reduces the immunity and passivity areas. A corrosion region exists between the immunity and passivity regions at 100 deg C at [Cu(aq)]tot=10-6 and [Cl(aq)]tot=0.2 molal. At the chlorine concentration of 1.5 molal the corrosion region exists in the whole temperature range investigated. The ion CuCl32- predominates at 5-25 and 100 deg C, while CuCl2- predominates at 50-80 deg C at [Cl(aq)]tot=1-5 molal. A copper concentration of 10-4 molal reduces the corrosion areas due to expansion of the immunity and passivity areas. However, a corrosion region still exists between the immunity and passivity regions at all investigated temperatures at pHΤ-6 molal and the chloride concentration of 0.2 molal. However, at 80-100 deg C the equilibrium potentials postulated for the Swedish nuclear repository are dangerously close to a corrosion situation. According to our calculations the copper canisters in the Swedish repository corrode at 80-100 deg C at the chloride concentration of 1.5 molal

  14. Releasing behavior of chlorine and fluorine during agricultural waste pyrolysis

    International Nuclear Information System (INIS)

    The releasing behavior of chlorine (Cl) and fluorine (F) during agricultural waste pyrolysis was investigated using a fixed-bed pyrolysis system with pyrohydrolytic-ion chromatography and thermodynamic equilibrium calculation. Agricultural waste contains a large amount of Cl-bearing species, among which approximately 30% is easily released with biomass drying. During biomass pyrolysis, Cl-bearing species evolve out rapidly to the gas phase, and higher temperature is favorable for the releasing. The releasing process can be divided into two ranges: the fast evaporating range (200–600 °C) and slow evaporating range (600–1000 °C). F shows similar transforming behavior. However, higher temperature is preferred for the release. Thermodynamic simulation shows that Cl mainly exists as KCl(g) at higher temperatures (>600 °C) with some HCl(g) and K2Cl2(g) as intermediate species at lower temperatures (<600 °C), whereas F mainly releases as SiF4 at higher temperatures (>500 °C) with SF5Cl being the dominant F-bearing species at lower temperatures (<500 °C). - Highlights: • The releasing behavior of fluorine during biomass pyrolysis was first studied. • The proportions of Cl and F in different products were examined. • Experiment and simulation were conducted to study the in-depth mechanism

  15. Electrokinetic-enhanced bioaugmentation for remediation of chlorinated solvents contaminated clay

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Xuhui, E-mail: x.mao@neu.edu [Civil and Environmental Engineering Department, Northeastern University, Boston, MA 02115 (United States); School of Resources and Environmental Science, Wuhan University, Wuhan 430079 (China); Wang, James [Geosyntec Consultants, Columbia, MA (United States); Ciblak, Ali [Civil and Environmental Engineering Department, Northeastern University, Boston, MA 02115 (United States); Cox, Evan E. [Geosyntec Consultants, Columbia, MA (United States); Riis, Charlotte [NIRAS A/S, Alleroed (Denmark); Terkelsen, Mads [Capital Region of Denmark, Hilleroed (Denmark); Gent, David B. [Environmental Laboratory, Engineer Research and Development Center (ERDC), US Army Corps of Engineers, Vicksburg, MS (United States); Alshawabkeh, Akram N., E-mail: aalsha@neu.edu [Civil and Environmental Engineering Department, Northeastern University, Boston, MA 02115 (United States)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Simultaneous delivery of electron donors and bacteria into low permeability clays. Black-Right-Pointing-Pointer Bacteria injection, growth and consequent transformation of contaminants are viable. Black-Right-Pointing-Pointer EK injection is more effective than advection-based injection for clay soil. Black-Right-Pointing-Pointer Electroosmosis appears to be the driving mechanism for bacteria injection. Black-Right-Pointing-Pointer Both EK transport and biodegradation contribute the removal of VOCs in clay. - Abstract: Successful bioremediation of contaminated soils is controlled by the ability to deliver bioremediation additives, such as bacteria and/or nutrients, to the contaminated zone. Because hydraulic advection is not practical for delivery in clays, electrokinetic (EK) injection is an alternative for efficient and uniform delivery of bioremediation additive into low-permeability soil and heterogeneous deposits. EK-enhanced bioaugmentation for remediation of clays contaminated with chlorinated solvents is evaluated. Dehalococcoides (Dhc) bacterial strain and lactate ions are uniformly injected in contaminated clay and complete dechlorination of chlorinated ethene is observed in laboratory experiments. The injected bacteria can survive, grow, and promote effective dechlorination under EK conditions and after EK application. The distribution of Dhc within the clay suggests that electrokinetic transport of Dhc is primarily driven by electroosmosis. In addition to biodegradation due to bioaugmentation of Dhc, an EK-driven transport of chlorinated ethenes is observed in the clay, which accelerates cleanup of chlorinated ethenes from the anode side. Compared with conventional advection-based delivery, EK injection is significantly more effective for establishing microbial reductive dechlorination capacity in low-permeability soils.

  16. 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

  17. Some kinetics aspects of chlorine-solids reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kanari, N.; Mishra, D.; Mochon, J.; Verdeja, L. F.; Diot, F.; Allain, E.

    2010-07-01

    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 Cl{sub 2}+N{sub 2} (chlorination), Cl{sub 2}+O{sub 2} (oxy chlorination), and Cl{sub 2}+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 degree centigrade. 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.. (Author) 12 refs.

  18. Chlorine-heavy metals interaction on toxicity and metal accumulation

    International Nuclear Information System (INIS)

    The primary objectives of this study with rainbow trout (Salmo gairdneri) were: to determine whether acute toxic interaction of chlorine, nickel, and temperature is additive, synergistic, antagonistic, or if no interaction occurs; to provide a biological explanation of the mechanisms of the toxic interactions; and to develop a mortality model of the toxic interaction. Twenty chlorine-nickel toxicity tests and a bioaccumulation study, both with and without chlorine, were conducted to accomplish these objectives. Studies using 63Ni were conducted to monitor the effects of chlorine on nickel accumulation in the tissues of trout under conditions similar to those of multiple toxicant studies. The presence of 0.018 ppM TRC (total residual chlorine) increased nickel accumulation in tissues from fish exposed to chlorine and 63Ni. This may be due to an increase in the permeability of the gill to nickel during chlorine exposure. Chlorine and nickel had a synergistic toxic interaction. Mortality in these groups was significantly higher. Temperature did not influence toxicity as strongly

  19. 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…

  20. 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

  1. 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...

  2. 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...

  3. 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.

  4. New infrared spectroscopic database for chlorine nitrate

    International Nuclear Information System (INIS)

    Fourier transform infrared measurements of chlorine nitrate have been performed in the spectral region 500-1330 cm-1 at 0.002-0.008 cm-1 spectral resolution. Absorption cross sections were derived from 23 spectra covering the temperature range from 190 to 296 K and air pressure range from 0 to 150 hPa. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 190 and 296 K. The sample was synthesized from N2O5 and Cl2O. Number densities in the absorption cell were derived from pressure measurements of the purified sample. Quality assurance included measurements with different sample pressures, spectroscopic purity check of the sample, comparison of integrated absorption cross sections over entire band systems, and assessment of residuals from remote-sensing retrievals. Multiplicative and additive errors were considered giving an overall uncertainty of +2.5/-3.5%. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The worst-case error for the interpolated data is +4.5/-5.5%. The database is well-suited for remote-sensing application and should reduce the atmospheric chlorine nitrate error budget substantially

  5. Release of chlorine from biomass at gasification conditions

    International Nuclear Information System (INIS)

    The objective of the project was to investigate the influence of different gasifying atmospheres on the release of chlorine from biomass during gasification conditions. Furthermore, the purpose was also to try and identify the formed chloro compounds. The results showed that O2, H2O and CO2 had negligible effect on the chlorine release at temperatures under 700 deg C. At temperatures above 800 deg C the reactivity towards CO2 increased and could be seen as higher chlorine release and less solid residue. No chloro organic compounds (aliphatic one to six carbons or aromatic one to two rings) could be detected in the tar or the fuel gas produced during pyrolysis/gasifying. On the other hand, comparable amounts of chlorinated benzenes were found in the cooling section during combustion of lucerne and of synthetic waste, indicating that oxygen is essential for chlorination reactions. 11 refs, 4 figs, 1 tab

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. Effective diffusivities of iodine, chlorine, and carbon in bentonite buffer material

    International Nuclear Information System (INIS)

    Effective diffusivities of iodine, chlorine, and carbon in mixtures of bentonite and sand were determined by measuring the effective diffusivities of common chemical compounds labeled with radioactive isotopes of these elements. For carbon, both inorganic and organic carbon compounds were used in order to consider the variety of chemical forms of carbon possible in a radioactive waste repository. The bentonite content and dry density of the bentonite-sand mixture were varied. Two chemically different aqueous solutions, representing concrete pore water and bentonite pore water, were used to represent different conditions that could affect diffusivity in bentonite buffer material in a hypothetical radioactive waste disposal situation. The effective diffusivities of iodine, chlorine, and carbon tended to decrease with increasing bentonite content and dry density of the mixture. In the presence of simulated concrete pore water, the effective diffusivities for iodine, chlorine, and carbon in the bentonite mixtures were not higher than those obtained when simulated bentonite pore water was used. Except for some organic compounds, the measured effective diffusivities were lower than that of tritiated water under the same experimental conditions. This was attributed primarily to exclusion of anions from the bentonite pores. The effective diffusivity of carbon depended on its chemical form. The effective diffusivity of the anionic forms of organic carbon tested (carboxylic acids) was as low as that of inorganic anionic carbon. Measured effective diffusivities were compared with those calculated using a model based on electrical double layer theory. The theory was applied to calculate distributions of electrolyte ions and diffusion ions in the bentonite pores. The calculated effective diffusivities showed good agreement with the measured values

  11. 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

  12. 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...

  13. Novel drug form of chlorin e6

    Science.gov (United States)

    Abakumova, O. Y.; Baum, Rudolf P.; Ermakova, Natalia Y.; Gradyushko, A. T.; Guseva-Donskaya, T. N.; Karmenyan, Artashes V.; Koraboyev, U. M.; Laptev, V. P.; Mechkov, V. M.; Mikhailova, L. M.; Panferova, N. G.; Rebeko, Aleksei G.; Reshetnickov, Andrei V.; Ryabov, M. V.; Stranadko, Eugeny P.; Tsvetkova, Tatyana A.; Zhukova, O. S.

    1999-12-01

    A novel stable water-soluble form of well known photosensitizer chlorin e6 named `Photodithazine' has been obtained from Spirulina Platensis cyanobacteria as a noncovalent complex with N-methyl-D-glucosamine, and its biological characteristics evaluate, which proved to be as follows: in vitro photocytotoxicity was 1 (mu) M (EC50) as determined by the extent of DNA synthesis inhibition in CaOv cells after irradiation with 650 - 900 nm light, and 5 (mu) M (EC65) as determined using MTT test on PC12 cells after irradiation with 670 nm laser light at the doses of 15 and 20 J/cm2, respectively, with Al-sulfophthalocyanine `Photosense' (Russia; oligomerized hematoporphyrin-IX mixture `Photogen', Russia) being used as permitted reference drugs.

  14. Emission of volatile chlorinated hydrocarbons from combustion of biofuels

    International Nuclear Information System (INIS)

    The emission of simple chlorinated compounds has been analyzed at five different cases at the district heating plant in Tranaas. The aim of this project has been to investigate the possibilities of finding a method for continuous monitoring of the emissions of chlorinated organic compounds from combustion. Samples were taken only after flue gas condensation. Three easily detectable chlorinated compounds could be quantified in spite of extremely low chlorine content in the fuel: * trichloroethylene, * tetrachloroethylene, * mono chlorinated benzene. Total amount of these compounds were > 0.2 mg/nm3. It is hard to find correlations between the emissions of chlorinated hydrocarbons and combustion conditions. One reason can be the sampling method which did not come up to our expectations. The high volatility of the solvent caused ice in the sampling train and most probably there has been great losses of the most volatile compounds. In spite of the fact that the combustion parameters in several samples were very good with low values of CO (0.2 mg/nm3 of monochlorinated benzene could be detected in the flue gas. Due to the unsatisfactory sampling method the real concentrations of the detected compounds are probably higher than the reported values. The amounts of chlorinated compounds detected are, in this plant, too low for continuous measurements. ( 6 refs., 14 figs., 4 tabs.)

  15. 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)

  16. 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.

  17. 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

  18. 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.

  19. 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)

  20. 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

  1. High sensitivity ultra-broad-band absorption spectroscopy of inductively coupled chlorine plasma

    Science.gov (United States)

    Marinov, Daniil; Foucher, Mickaël; Campbell, Ewen; Brouard, Mark; Chabert, Pascal; Booth, Jean-Paul

    2016-06-01

    We propose a method to measure the densities of vibrationally excited Cl2(v) molecules in levels up to v  =  3 in pure chlorine inductively coupled plasmas (ICPs). The absorption continuum of Cl2 in the 250–450 nm spectral range is deconvoluted into the individual components originating from the different vibrational levels of the ground state, using a set of ab initio absorption cross sections. It is shown that gas heating at constant pressure is the major depletion mechanism of the Cl2 feedstock in the plasma. In these line-integrated absorption measurements, the absorption by the hot (and therefore rarefied) Cl2 gas in the reactor centre is masked by the cooler (and therefore denser) Cl2 near the walls. These radial gradients in temperature and density make it difficult to assess the degree of vibrational excitation in the centre of the reactor. The observed line-averaged vibrational distributions, when analyzed taking into account the radial temperature gradient, suggest that vibrational and translational degrees of freedom in the plasma are close to local equilibrium. This can be explained by efficient vibrational-translational (VT) relaxation between Cl2 and Cl atoms. Besides the Cl2(v) absorption band, a weak continuum absorption is observed at shorter wavelengths, and is attributed to photodetachment of Cl‑ negative ions. Thus, line-integrated densities of negative ions in chlorine plasmas can be directly measured using broad-band absorption spectroscopy.

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

    International Nuclear Information System (INIS)

    The chlorination kinetics of niobium pentoxide in the presence of carbon monoxide between 500-8000C of temperature is studied. The following variable that influences on the reaction rate are analysed: gas flow, geometry and volume of the Nb2O5 samples, reaction temperature and composition of the chlorinated mixture. At the same time, two other materials were studied: the CaO.Nb2O5 (synthetized in laboratory) and pyrochlorine concentrates. The three materials are compared for the chlorination method used. (M.A.C.)

  3. 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

  4. 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...

  5. 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...

  6. Effect of Chlorine on Giardia lamblia Cyst Viability

    OpenAIRE

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

    1981-01-01

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

  7. 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...

  8. 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.

  9. 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

  10. 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...

  11. TOXICITY OF RESIDUAL CHLORINE COMPOUNDS TO AQUATIC ORGANISMS

    Science.gov (United States)

    Laboratory studies on the acute and chronic toxicity of chlorine and inorganic chloramines to trout, salmon, minnows, bullhead, largemouth bass, and bluegill were conducted. Acute toxicity under continuous and intermittent patterns of exposure as well as behavioral, reproduction,...

  12. 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.

  13. 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...

  14. 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.

  15. 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...

  16. 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

  17. Bioremediation of chlorinated ethenes in aquifer thermal energy storage

    NARCIS (Netherlands)

    Ni, Z.

    2015-01-01

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

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

    Science.gov (United States)

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

  19. 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,...

  20. 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.

  1. 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.

  2. 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...

  3. 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...

  4. 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

  5. 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

  6. Oxidation of manganese(II) during chlorination: role of bromide.

    Science.gov (United States)

    Allard, S; Fouche, L; Dick, J; Heitz, A; von Gunten, U

    2013-08-01

    The oxidation of dissolved manganese(II) (Mn(II)) during chlorination is a relatively slow process which may lead to residual Mn(II) in treated drinking waters. Chemical Mn(II) oxidation is autocatalytic and consists of a homogeneous and a heterogeneous process; the oxidation of Mn(II) is mainly driven by the latter process. This study demonstrates that Mn(II) oxidation during chlorination is enhanced in bromide-containing waters by the formation of reactive bromine species (e.g., HOBr, BrCl, Br2O) from the oxidation of bromide by chlorine. During oxidation of Mn(II) by chlorine in bromide-containing waters, bromide is recycled and acts as a catalyst. For a chlorine dose of 1 mg/L and a bromide level as low as 10 μg/L, the oxidation of Mn(II) by reactive bromine species becomes the main pathway. It was demonstrated that the kinetics of the reaction are dominated by the adsorbed Mn(OH)2 species for both chlorine and bromine at circumneutral pH. Reactive bromine species such as Br2O and BrCl significantly influence the rate of manganese oxidation and may even outweigh the reactivity of HOBr. Reaction orders in [HOBr]tot were found to be 1.33 (±0.15) at pH 7.8 and increased to 1.97 (±0.17) at pH 8.2 consistent with an important contribution of Br2O which is second order in [HOBr]tot. These findings highlight the need to take bromide, and the subsequent reactive bromine species formed upon chlorination, into account to assess Mn(II) removal during water treatment with chlorine. PMID:23859083

  7. 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...

  8. 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.

  9. Bio-remediation of aquifers polluted by chlorinated solvents

    International Nuclear Information System (INIS)

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

  10. 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.

  11. Structural Insights into Regioselectivity in the Enzymatic Chlorination of Tryptophan

    OpenAIRE

    Zhu, Xiaofeng; De Laurentis, Walter; Leang, Khim; Herrmann, Julia; Ihlefeld, Katja; van Pée, Karl-Heinz; Naismith, James H.

    2009-01-01

    The regioselectively controlled introduction of chlorine into organic molecules is an important biological and chemical process. This importance derives from the observation that many pharmaceutically active natural products contain a chlorine atom. Flavin-dependent halogenases are one of the principal enzyme families responsible for regioselective halogenation of natural products. Structural studies of two flavin-dependent tryptophan 7-halogenases (PrnA and RebH) have generated important ins...

  12. 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-chloro......-chloroindoleacetic acid from pea and in the cancerostatic maytansinoids. Many compounds are chlorohydrins isolated along with the related epoxides. Some compounds, like gibberellin A6 hydrochloride from bean, are perhaps artefacts....

  13. Comparison of ion chromatography and flow injection analysis methods for monitoring chlorite and chlorate ions in drinking water

    OpenAIRE

    Ledder, Tracey

    1991-01-01

    Up-coming regulations on chlorine dioxide in drinking water treatment require low level measurement of chlorite ion (CI02-) and chlorate ion (CI03-). This research investigated analysis of CI02- and CI03-; in drinking water by flow injection analysis with iodometric detection (FIA) and ion chromatography with conductivity detection (IC). Both the FIA and IC methods were accurate for the determination of CIO2-; and CIO3-; in reagent water. The IC method was accurate in dr...

  14. 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.

  15. 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.

  16. The synergistic effect of Escherichia coli inactivation by sequential disinfection with low level chlorine dioxide followed by free chlorine.

    Science.gov (United States)

    Yang, Wu; Yang, Dong; Zhu, Sui-Yi; Chen, Bo-Yan; Huo, Ming-Xin; Li, Jun-Wen

    2012-12-01

    To the best of our knowledge, there was little information available on pathogen removal using low level disinfectant followed by free chlorine in sequential disinfection (SD). This study investigated Escherichia coli inactivation by four types of disinfection: single step disinfection (SSD), SD, traditional sequential disinfection (TSD) and mixed disinfectant disinfection (MDD). Results indicated that SD had higher ability to inactivate E. coli than the others, indicating there was a positive synergistic effect on chlorine disinfection by prior dosing with a low level of chlorine dioxide (ClO(2)). The ONPG assay suggested that the permeability of cell wall rather than the viability of E. coli were changed under 0.02 mg/l ClO(2) treatment. The coexistence of residual ClO(2) and free chlorine also plays an active synergistic effect. Additionally, temperature had a positive effect on E. coli inactivation in SD, while inactivation was reduced in alkaline compared to neutral and acidic conditions. PMID:23165713

  17. 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

  18. 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.

  19. 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

  20. Modelling of the natural chlorine cycling in a coniferous stand: implications for chlorine-36 behaviour in a contaminated forest environment

    International Nuclear Information System (INIS)

    Considered as one of the most available radionuclide in soil–plant system, 36Cl is of potential concern for long-term management of radioactive wastes, due to its high mobility and its long half-life. To evaluate the risk of dispersion and accumulation of 36Cl in the biosphere as a consequence of a potential contamination, there is a need for an appropriate understanding of the chlorine cycling dynamics in the ecosystems. To date, a small number of studies have investigated the chlorine transfer in the ecosystem including the transformation of chloride to organic chlorine but, to our knowledge, none have modelled this cycle. In this study, a model involving inorganic as well as organic pools in soils has been developed and parameterised to describe the biogeochemical fate of chlorine in a pine forest. The model has been evaluated for stable chlorine by performing a range of sensitivity analyses and by comparing the simulated to the observed values. Finally a range of contamination scenarios, which differ in terms of external supply, exposure time and source, has been simulated to estimate the possible accumulation of 36Cl within the different compartments of the coniferous stand. The sensitivity study supports the relevancy of the model and its compartments, and has highlighted the chlorine transfers affecting the most the residence time of chlorine in the stand. Compared to observations, the model simulates realistic values for the chlorine content within the different forest compartments. For both atmospheric and underground contamination scenarios most of the chlorine can be found in its organic form in the soil. However, in case of an underground source, about two times less chlorine accumulates in the system and proportionally more chlorine leaves the system through drainage than through volatilisation. - Highlights: ► 36Cl is of potential concern for long-term management of radioactive wastes. ► There is a need for an appropriate understanding of the Cl

  1. 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...

  2. 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.

  3. 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...

  4. 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.

  5. Reductive dechlorination of chlorinated solvents in landfills

    International Nuclear Information System (INIS)

    The use of landfills as an in situ biological treatment system represents an alternative for source area remediation with a significant cost saving. The specific objective of this research is to investigate the intrinsic bioattenuation capacity of the landfill ecosystem for chlorinated aliphatic hydrocarbons (CAHs). The research was conducted in two complementary systems: simulated landfill bioreactors and batch degradation experiment in serum bottles. Refuse samples excavated from a landfill were tested in laboratory bioreactors designed and operated to facilitate refuse decomposition under landfilling conditions. Each bioreactor was operated with leachate recirculation and gas collection. Target CAHs, tetrachloroethene (PCE) and trichloroethene (TCE), were added to selected reactors and maintained at 20 μM each in leachate to simulate the effect of long-term exposure of refuse microorganisms to CAHs on the degradation potential of these chemicals in landfills. At two different stages of refuse decomposition, active refuse decomposition representing young landfills and maturation phase representing aged landfills, anaerobic microbial cultures were derived from selected bioreactors and tested in serum bottles for their abilities to biodegrade target CAHs. Results of this study suggest that landfills have an intrinsic reductive dechlorination capacity for PCE and TCE. The decomposition of refuse, a source of complex organics, enhances reductive dechlorination by the refuse cultures tested in this study. In addition, the test results suggest that it may be possible to develop engineering strategies to promote both CAHs degradation and refuse decomposition in landfills. (author)

  6. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Directory of Open Access Journals (Sweden)

    Ulrich Kunz

    2012-07-01

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

  7. Health effects of disinfection by-products in chlorinated swimming pools.

    Science.gov (United States)

    Florentin, Arnaud; Hautemanière, Alexis; Hartemann, Philippe

    2011-11-01

    Increased attendance at swimming pools is correlated with higher input of organic and minerals pollutants introduced by swimmers in the swimming pool water. In most swimming pools, microbiological control is performed by disinfection with the addition of chlorine. Chlorine is now well-known to lead to the formation of many disinfection by-products (DBPs) including trihalomethanes and chloramines. The hypothesis of a link between the presence of eye and skin irritation syndromes in swimmers and contact with swimming pool water treated with chlorine was initially proposed by Mood (1953). During recent decades many epidemiological studies have described the importance of DBPs generated with natural or imported organic matter present in water. Many of these DBPs are suspected to be toxic or even carcinogenic. Trihalomethanes and haloacetic acid families are the most studied but others DBPs, like chloral hydrate, haloacetonitriles, N-nitrosodimethylamine and the bromate ion, are emerging compounds of interest. Epidemiological data about the risk of cancer are still controversial. However, numerous publications highlight a toxic risk especially the risk of allergy and respiratory symptoms for babies and elite swimmers. The few publications dedicated to risk assessment do not suggest increased risk, other than for elite swimmers. These publications are likely to underestimate the risk associated with DBPs because of the lack of data in the literature precludes the calculation of risk associated with certain compounds or certain pathways. Thus for regulations, the need to take into account the risks associated with disinfection by-products is now important without forgetting the need of the control of microbiological hazards in swimming pools. PMID:21885333

  8. 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.

  9. Chlorinated and Non chlorinated-Volatile Organic Compounds (Vocs) in Drinking Water of Peninsular Malaysia

    International Nuclear Information System (INIS)

    A survey undertaken in Peninsular Malaysia has shown that volatile organic compounds (VOCs), both chlorinated and non-chlorinated, are present in selected drinking water samples. In this study, analyses of VOCs were performed by means of solid phase micro extraction (SPME) with a 100 μm polydimethylsiloxane (PDMS) fibre followed by gas chromatography - mass spectrometry detector (GC-MSD). Samples from different points of the distribution system networks were taken and analysed for 54 VOCs of different chemical families. The results of the study indicated that chloroform constituted the major portion of the VOCs in all samples analysed. In addition to trihalo methanes (THMs), other abundant compounds detected were cis and trans-1,2-dichloroethylene, trichloroethylene, 1,2-dibromoethane, benzene, toluene, ethylbenzene, chlorobenzene, 1,4-dichlorobenzene and 1,2-dichlorobenzene. However, the measured concentrations did not exceed the National Guideline for Drinking Water Quality 2000 in any case. No clear relationship between the status of development of a state in Malaysia to the levels and types of VOCs detected in its drinking water was noted. Nevertheless, the finding of anthropogenic chemicals, even at low concentrations, gave credibility to the viewpoint that improper development and disposal practices threatened the purity of the drinking water. (author)

  10. 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.

  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. Efficacy of copper and silver ions with iodine in the inactivation of Pseudomonas cepacia

    Science.gov (United States)

    Pyle, B. H.; Broadaway, S. C.; McFeters, G. A.

    1992-01-01

    Alternatives to chlorination of water have been sought for reasons which include trihalomethane formation, possible bacterial regrowth, the high concentrations of chlorine required in certain circumstances, and the taste, odour and bodily irritation in chlorine-treated water. Electrolytically generated Cu and Ag ions at low levels, in addition to very low chlorine concentrations, have been suggested as an alternative to routine chlorination. We have examined the combination of Cu and Ag ions with low levels of iodine. Pseudomonas cepacia was grown either in rich medium or under nutrient restriction prior to disinfection. Survival of the organism and its ability to regrow after treatment as well as the effects of varying buffers, metal ion and iodine concentrations were determined. Low concentrations of metal ions (100 ppb Cu and 11 ppb Ag) and iodine (200 ppb) were more effective than either metal ions or iodine alone against Ps. cepacia grown on rich agar or in low nutrient buffer. After iodination, buffer-grown suspensions recovered to their original cell concentrations within 7 d. When Cu and Ag ions were used with or without iodine, regrowth was prevented. The results show that low concentrations of Cu and Ag in combination with iodine permit effective disinfection of bacteria after cultivation on either rich media or under nutrient restriction. These results, along with published data, suggest that the combination of these metals with halogenation may have applications in the disinfection of both recreational and potable water.

  13. 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.

  14. Halopyrroles: a new group of highly toxic disinfection byproducts formed in chlorinated saline wastewater.

    Science.gov (United States)

    Yang, Mengting; Zhang, Xiangru

    2014-10-21

    Utilizing seawater for toilet flushing is an effective way to conserve freshwater in coastal cities. During chlorination for disinfecting saline wastewater effluents, the high levels of bromide from seawater are oxidized to hypobromous acid which may then react with effluent organics to form brominated disinfection byproducts (DBPs). In this research, by applying a new precursor ion scan method, we detected and identified a group of halopyrroles in a chlorinated saline wastewater effluent, including tetrabromopyrrole, tribromochloropyrrole, tribromoiodopyrrole, and tribromopyrrole, with tetrabromopyrrole as the predominant species. It is the first time that this group of halopyrroles were identified as wastewater DBPs (though 2,3,5-tribromopyrrole has been found to be a DBP in drinking water before). Detection of halopyrroles was problematic as these compounds in the pretreated samples were found to convert to halonitropyrroles; the problem was successfully solved by diluting the pretreated samples. The formation, occurrence, precursor, and toxicity of tetrabromopyrrole were investigated. This DBP showed significantly higher developmental toxicity than any of the haloaliphatic and haloaromatic DBPs previously tested. PMID:25236171

  15. 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.

  16. Chlorine solubility in evolved alkaline magmas

    Directory of Open Access Journals (Sweden)

    M. R. Carroll

    2005-06-01

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

  17. 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

  18. Development of measurement technology of chlorine attached on canister using laser. Development of measurement device and quantification of attached chlorine concentration for measurement scenario during storage of spent fuel

    International Nuclear Information System (INIS)

    Chlorine concentration of salt attached on stainless steel, which is a candidate for the canister material of concrete cask, was measured by laser-induced breakdown spectroscopy (LIBS) for the purpose of the measurement during the storage of spent fuel. In order to measure a salt in a narrow gap between a canister and a concrete body, the compact optical device was developed to measure emission spectra by adopting the optical setup of a collinear configuration. In addition, LIBS system was developed for detecting chlorine emission spectra. Using a compact optical device, salt attached on a stainless-steel was measured vertically in the narrow space simulating the gap between a canister and a concrete body. The results of LIBS were coincident with the result of ion chromatography. These results show the possibility of quantitative measurement of chlorine on canister by LIBS for monitoring the environmental condition for stress corrosion cracking of canister in the concrete body. The series of LIBS experiments for the purpose of the measurement of salt attached on the canister made clear the agenda, such as the acquisition of the data set of calibration curve in various experimental conditions for the qualification of LIBS results, for adopting the method to an concrete cask. (author)

  19. Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, T., E-mail: uchida-t@toyo.jp [Bio-Nano Electronics Research Centre, Toyo University, Kawagoe 350-8585 (Japan); Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe 350-8585 (Japan); Rácz, R.; Biri, S. [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/C, H-4026 Debrecen (Hungary); Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), Chiba 263-8555 (Japan); Kato, Y. [Graduate School of Engineering, Osaka University, Suita 565-0871 (Japan); Yoshida, Y. [Bio-Nano Electronics Research Centre, Toyo University, Kawagoe 350-8585 (Japan); Faculty of Science and Engineering, Toyo University, Kawagoe 350-8585 (Japan)

    2016-02-15

    We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron.

  20. Two-chamber configuration of Bio-Nano electron cyclotron resonance ion source for fullerene modification

    International Nuclear Information System (INIS)

    We report on the modification of fullerenes with iron and chlorine using two individually controllable plasmas in the Bio-Nano electron cyclotron resonance ion source (ECRIS). One of the plasmas is composed of fullerene and the other one is composed of iron and chlorine. The online ion beam analysis allows one to investigate the rate of the vapor-phase collisional modification process in the ECRIS, while the offline analyses (e.g., liquid chromatography-mass spectrometry) of the materials deposited on the plasma chamber can give information on the surface-type process. Both analytical methods show the presence of modified fullerenes such as fullerene-chlorine, fullerene-iron, and fullerene-chlorine-iron

  1. 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.

  2. 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

  3. 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.

  4. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-15

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

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

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

    International Nuclear Information System (INIS)

    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 log10 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 log10 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

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

    Science.gov (United States)

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

    2016-01-15

    Sulfonamides (SAs) are one class of the most widely used antibiotics around the world and have been frequently detected in municipal wastewater and surface water in recent years. Their transformation in waste water treatment plants (WWTP) and in water treatment plants (WTP), as well as, their fate and transport in the aquatic environment are of concern. The reaction of six sulfonamides (sulfamethoxazole, sulfapyridine, sulfamethazine, sulfamerazine, sulfathiazole and sulfadiazine) with free chlorine was investigated at a laboratory scale in order to identify the main chlorination by-products. A previously validated method, liquid chromatography/mass spectrometry, was used to analyse SAs and their chlorination by-products. At room temperature, pH 6-7, reaction times of up to 2 h and an initial concentration of 2 mg/L of free chlorine, the majority of SAs suffered degradation of around 65%, with the exception of sulfamethoxazole and sulfathiazole (20%). The main reaction of SAs with free chlorine occurred in the first minute. PMID:26560639

  13. 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.

  14. Radiation enhanced thermal 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. It is a contribution to PRECCI programme (research programme on the long-term behaviour of the spent nuclear fuel). 36Cl is a long lived volatile activation product (T = 300 000 years) able to contribute significantly to the instant release fraction in geological disposal conditions. 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 deg. C; we showed that implanted chlorine was mobile from temperatures as low as 1000 deg. C and determined a thermal diffusion coefficient D1000deg.C around 10-16 cm2s-1 and deduced an activation energy of 4.3 eV. This value is one of lowest compared to that of volatile fission products such as iodine or the xenon. These parameters reflect the very mobile behaviour of chlorine; - the irradiation effects induced by fission products were studied by irradiating the samples with 127I (energy of 63.5 MeV). We showed that the implanted chlorine diffusion in the temperature range 30 - 250 deg. C is not purely athermal. In these conditions, the diffusion coefficient D250deg.C for the implanted chlorine is around 10-14 cm2s-1 and the activation energy is calculated to be 0.1 eV. Moreover, at 250 deg. C, we observed an important transport of the pristine chlorine from the bulk towards the surface. This chlorine comes from a zone where the defects are mainly produced by the nuclear energy loss process at the end of iodine range. We showed the importance of the implantation and irradiation defects as preferential paths for a fast chlorine transport. We carried out ab initio

  15. Use of orbitrap-MS/MS and QSAR analyses to estimate mutagenic transformation products of iopamidol generated during ozonation and chlorination.

    Science.gov (United States)

    Matsushita, Taku; Hashizuka, Masahiro; Kuriyama, Taisuke; Matsui, Yoshihiko; Shirasaki, Nobutaka

    2016-04-01

    The effects of two water purification processes (ozonation, and chlorination after ozonation) on the mutagenicity of a solution containing iopamidol (X-ray contrast medium) were investigated by using the Ames assay. No mutagenicity was observed during ozonation. In contrast, mutagenicity was induced by the ozone-treated iopamidol-containing solution after subsequent chlorination, indicating that mutagenic transformation-products (TPs) were generated. Ten of 70 peaks detected on the LC/MS total ion chromatogram (TIC) of the ozone-treated iopamidol-containing solution after chlorination had a positive correlation (r(2) > 0.6) between their peak areas and the observed mutagenicity, suggesting that TPs detected as these peaks may induce mutagenicity. To narrow down the possible contributors to the observed mutagenicity, we compared the areas of the peaks on the TIC-charts with and without chlorination. Of the ten peaks, six were also detected in the ozone-treated iopamidol-containing solution without chlorination, which did not induce mutagenicity, indicating that these peaks were not related to the observed mutagenicity. Accurate m/z values and MS/MS analysis with an orbitrap MS of the remaining four peaks revealed that two of them represented the same TP in the negative and positive ion modes. The three remaining TPs were assessed in four quantitative structure-activity relationship models for predicting Ames mutagenicity. At least one model predicted that two of the three TPs were mutagenic, whereas none of the models predicted that the other TP was a mutagen, suggesting that the former TPs, estimated as N1-acetyl-5-amino-6-chloro-2-iodobenzene-1,3-dicarboxamide and 3-hydroxy-2-{3-[(2-hydroxyethoxy)carbonyl]-2,4,6-triiodo-5-nitrobenzoyl}amino)propanoic acid, could be the candidate compounds that contributed to the observed mutagenicity. PMID:26807944

  16. Chlorinated Hydrocarbon Degradation in Plants: Mechanisms and Enhancement of Phytoremediation of Groundwater Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Stuart E.

    2002-06-01

    Several varieties of transgenic poplar containing cytochrome P-450 2E1 have been constructed and are undergoing tests. Strategies for improving public acceptance and safety of transgenic poplar for chlorinated hydrocarbon phytoremediation are being developed. We have discovered a unique rhizobium species that lives within the stems of poplar and we are investigating whether this bacterium contributes nitrogen fixed from the air to the plant and whether this endophyte could be used to introduce genes into poplar. Studies of the production of chloride ion from TCE have shown that our present P-450 constructs did not produce chloride more rapidly than wild type plants. Follow-up studies will determine if there are other rate limiting downstream steps in TCE metabolism in plants. Studies of the metabolism of carbon tetrachloride in poplar cells have provided evidence that the native plant metabolism is due to the activity of oxidative enzymes similar to the mammalian cytochrome P-450 2E1.

  17. Chlorinated hydrocarbon contaminants in arctic marine mammals.

    Science.gov (United States)

    Norstrom, R J; Muir, D C

    1994-09-16

    By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals. Except in the Russian Arctic, data have now been obtained on the temporospatial distribution of PCBs and other contaminants in ringed seal, beluga and polar bear. Contaminants in narwhal (Monodon monoceros) have also now been measured. On a fat weight basis, the sum of DDT-related compounds (S-DDT) and PCB levels are lowest in walrus (< 0.1 microgram/g), followed by ringed seal, (0.1-1 microgram/g range). Levels are an order of magnitude higher in beluga and narwhal (1-10 micrograms/g range). It appears that metabolism and excretion of S-DDT and PCBs may be less efficient in cetaceans, leading to greater biomagnification. Polar bears have similar levels of PCBs as cetaceans (1-10 micrograms/g), but with a much simpler congener pattern. DDE levels are lowest in polar bear, indicating rapid metabolism. Effects of age and sex on residue levels are found for all species where this was measured. Among cetaceans and ringed seal, sexually mature females have lower levels than males due to lactation. Although PCB levels in adult male polar bears are about twice as high as females, there is only a trivial age effect in either sex apart from an initial decrease from birth to sexual maturity (age 0-5). Comparison of levels of S-DDT and PCBs in Arctic beluga and ringed seal with those in beluga in the Gulf of St

  18. Experimental cancer studies of chlorinated by-products

    International Nuclear Information System (INIS)

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

  19. Oxidation of synthetic phenolic antioxidants during water chlorination.

    Science.gov (United States)

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

    2012-01-15

    The degradation of seven phenolic antioxidants and metabolites during chlorination was investigated. Under strong chlorination conditions (10 mg L(-1) chlorine, 24h), five of the target compounds were significantly degraded, while only BHT-Q (2,6-di-tert-butylcyclohexa-2,5-diene-1,4-dione) and BHT-CHO (3,5-di-tert-butyl-4-hydroxybenzaldehyde) were stable. The effect of the presence of bromide to the sample was only significant for BHA (butylated hydroxyanisole) resulting in increased disappearance rate as it is increased. Moreover, the disappearance kinetics were investigated at different concentrations of chlorine and pH of sample using a factorial experimental design. It was observed that the pH of the sample was a significant factor for BHT (butylated hydroxytoluene) and BHA, and chlorine concentration was significant for BHT, resulting in increased disappearance kinetics as they are increased. The degradation of these compounds has revealed two main processes: hydroxylation and oxidation of the aromatic system. The hydroxylated derivatives in some cases (e.g. from BHT-OH (2,6-di-tert-butyl-4-(hydroxymethyl)phenol) and BHT-COOH (3,5-di-tert-butyl-4-hydroxybenzoic acid)) are formed via the chlorinated and/or brominated intermediate. Moreover, the oxidation of the aromatic system leads to the quinone derivatives. The investigation of these by-products in real samples by solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) showed that derivatives of BHT, BHT-OH and/or BHT-COOH occurred in wastewater and drinking water samples analysed. PMID:22093692

  20. 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

  1. 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)

  2. 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 (...

  3. Chlorine isotopic geochemistry of salt lakes in the Qaidam Basin, China

    Digital Repository Service at National Institute of Oceanography (India)

    Liu, W.G.; Xiao, Y.K.; Wang, Q.Z.; Qi, H.P.; Wang, Y.H.; Zhou, Y.M.; Shirodkar, P.V.

    The isotopic compositions of chlorine in salt lake brine coexisting with halite, oil-field water and river water from the Qaidam Basin (Qinghai, China) have been examined using high-precision measurement of chlorine isotopes based on thermal...

  4. 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)

  5. 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.

  6. Biosynthesis of chlorine-containing compounds in Menispermum Dauricum root cultures

    International Nuclear Information System (INIS)

    Effects of chloride ion on production of acutumine and dechloroactumine, by Menispermum dauricum root culture, were studied. The chloride ion contents in the medium play a key role in production of both alkaloids. A medium with low chloride contents promoted production of dechloroactumine and suppressed that of acutumine. Production of the two alkaloids during the 60 days culture period was closely associated with root biomass. Both alkaloids accumulated in the roots and a relatively small proportion was exuded into the medium. The intact plant produced very little amounts of both alkaloids. On the average roots contained 22 and 75-fold more acutumine and dechloroactumine, respectively, than the intact plants. The biosythetic relationship between acutumine and dechloroactumine was studied using 13C-labeled tyrosine and 3H-labeled dechloroactumine as tracers. 13C-NMR spectra of 13C-labeled acutumine and dechloroactumine showed that the alkaloids, each composed of two molecules of tyrosine, are derived from the same biosythetic pathway. Feeding Menispermum dauricum roots, cultured in a chloride-enriched medium, with 3H-labeled dechloroactumine demonstrated that actumine is the only alkaloid metabolite of dechloroactumine. Conversion (5%) of the exogenously applied dechloroactumine, taken up by the roots, into acutumine showed that dechloroactumine is the precursor of acutumine. Incomplete conversion of dechloroactumine into acutumine suggests accumulation of the exogenously applied dechloroactumine in cell organelles and/or compartmentation of the enzymes involved in the biosynthesis of acutumine. In addition to acutumine, acutumidine and two new chlorine-containing alkaloids, named 1-epiacutumine, and 1-piacutumine, were isolated from M. Dauricum root cultures and the intact plants. Their structures were determined based on MS and 1H and 13C NMR spectra. Accumulations of these alkaloids were found to be low in the intact plant compared with the cultured roots. Crude

  7. Reductive cleavage of chlorine from 6-chloronicotinic acid on mercury electrodes

    International Nuclear Information System (INIS)

    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 H2SO4 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+ ion and an electron.

  8. 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.

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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.

  14. 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

  15. Total oxidation of chlorinated VOCs on supported oxide catalysts

    OpenAIRE

    Bertinchamps, Fabrice

    2005-01-01

    Biomass-fed cogeneration units and waste incinerators have the advantages of producing efficiently heat and power and of reducing the amount of CO2 emitted per produced energy. However, they produce toxic polychlorinated VOCs (dioxins), CO and NOx. This thesis aims at developing a catalytic system for the total oxidation of chlorinated VOCs that: i) convert efficiently chlorinated VOCs below 250 °C and ii) resist to the exhaust co-pollutants (H2O, CO, NOx). Moreover, this thesis aims at havin...

  16. Zirconium tetrachloride production using the fluidized bed chlorination technique

    International Nuclear Information System (INIS)

    In this paper the results of a study of the process for production nuclear grade zirconium tetrachloride by fluidized bed chlorination technique are presented. A reactor with a gas distributor has been developed and this permitted to establish a procedure of zirconium tetrachloride production with adequate purity, satisfactories efficiency of reaction and reproducible results. Some relevant parameters of the kinetics of chlorination process such as: time and temperature of reaction, size and minimum fluidizing velocity of microspheres and percentage of the reducing agent have been studied. (author). 15 refs., 5 figs

  17. Ion flux and ion distribution function measurements in synchronously pulsed inductively coupled plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Brihoum, Melisa; Cunge, Gilles; Darnon, Maxime; Joubert, Olivier [Laboratoire des Technologies de la Microelectronique CNRS, Grenoble Cedex 9, Isere 38054 (France); Gahan, David [Impedans Ltd., Dublin 17 (Ireland); Braithwaite, Nicholas St. J. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2013-03-15

    Changes in the ion flux and the time-averaged ion distribution functions are reported for pulsed, inductively coupled RF plasmas (ICPs) operated over a range of duty cycles. For helium and argon plasmas, the ion flux increases rapidly after the start of the RF pulse and after about 50 {mu}s reaches the same steady state value as that in continuous ICPs. Therefore, when the plasma is pulsed at 1 kHz, the ion flux during the pulse has a value that is almost independent of the duty cycle. By contrast, in molecular electronegative chlorine/chlorosilane plasmas, the ion flux during the pulse reaches a steady state value that depends strongly on the duty cycle. This is because both the plasma chemistry and the electronegativity depend on the duty cycle. As a result, the ion flux is 15 times smaller in a pulsed 10% duty cycle plasma than in the continuous wave (CW) plasma. The consequence is that for a given synchronous RF biasing of a wafer-chuck, the ion energy is much higher in the pulsed plasma than it is in the CW plasma of chlorine/chlorosilane. Under these conditions, the wafer is bombarded by a low flux of very energetic ions, very much as it would in a low density, capacitively coupled plasma. Therefore, one can extend the operating range of ICPs through synchronous pulsing of the inductive excitation and capacitive chuck-bias, offering new means by which to control plasma etching.

  18. Ion flux and ion distribution function measurements in synchronously pulsed inductively coupled plasmas

    International Nuclear Information System (INIS)

    Changes in the ion flux and the time-averaged ion distribution functions are reported for pulsed, inductively coupled RF plasmas (ICPs) operated over a range of duty cycles. For helium and argon plasmas, the ion flux increases rapidly after the start of the RF pulse and after about 50 μs reaches the same steady state value as that in continuous ICPs. Therefore, when the plasma is pulsed at 1 kHz, the ion flux during the pulse has a value that is almost independent of the duty cycle. By contrast, in molecular electronegative chlorine/chlorosilane plasmas, the ion flux during the pulse reaches a steady state value that depends strongly on the duty cycle. This is because both the plasma chemistry and the electronegativity depend on the duty cycle. As a result, the ion flux is 15 times smaller in a pulsed 10% duty cycle plasma than in the continuous wave (CW) plasma. The consequence is that for a given synchronous RF biasing of a wafer-chuck, the ion energy is much higher in the pulsed plasma than it is in the CW plasma of chlorine/chlorosilane. Under these conditions, the wafer is bombarded by a low flux of very energetic ions, very much as it would in a low density, capacitively coupled plasma. Therefore, one can extend the operating range of ICPs through synchronous pulsing of the inductive excitation and capacitive chuck-bias, offering new means by which to control plasma etching.

  19. 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...

  20. 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...

  1. 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...

  2. 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 ...

  3. Coal and coke - Analysis and testing - Coal and coke - Chlorine - High-temperature combustion method

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-09-29

    This Standard sets out a method for the liberation of the chlorine from coal and coke by high-temperature combustion, and its subsequent determination by titrimetry. The presence of residual halogen-bearing organic float-and-sink liquids in coal samples will affect the determination of chlorine. This Standard is applicable to coal and coke containing less than 0.3% chlorine.

  4. 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

  5. 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

  6. Processing of molybdenite concentrates by low-temprature chlorination roasting

    OpenAIRE

    Александров, Павло Володимирович

    2012-01-01

    Prospects of low-temperature chlorination roasting with chlorides of alkaline metals application for processing of molybdenite concentrate are shown. General benefits of it are reduction of evolving of dioxide of sulfur in the atmosphere, reduction of roasting temperature to 450 ºС and formation of water-soluble compounds of molybdenum during roasting

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    function 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...

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

    Science.gov (United States)

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

    2015-09-01

    The Moon contains chlorine that is isotopically unlike that of any other body yet studied in the Solar System, an observation that has been interpreted to support traditional models of the formation of a nominally hydrogen-free ("dry") Moon. We have analyzed abundances and isotopic compositions of Cl and H in lunar mare basalts, and find little evidence that anhydrous lava outgassing was important in generating chlorine isotope anomalies, because (37)Cl/(35)Cl ratios are not related to Cl abundance, H abundance, or D/H ratios in a manner consistent with the lava-outgassing hypothesis. Instead, (37)Cl/(35)Cl correlates positively with Cl abundance in apatite, as well as with whole-rock Th abundances and La/Lu ratios, suggesting that the high (37)Cl/(35)Cl in lunar basalts is inherited from urKREEP, the last dregs of the lunar magma ocean. These new data suggest that the high chlorine isotope ratios of lunar basalts result not from the degassing of their lavas but from degassing of the lunar magma ocean early in the Moon's history. Chlorine isotope variability is therefore an indicator of planetary magma ocean degassing, an important stage in the formation of terrestrial planets. PMID:26601265

  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...

  10. 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 ...

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    From Veronica longifolia were isolated three chlorinated iridoid glucosides, namely asystasioside E (6) and its 6-O-esters 6a and 6b, named longifoliosides A and B, respectively. The structures of 6a and 6b were proved by analysis of their spectroscopic data and by conversion to the catalpol este......), superoxide (SO), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals....

  12. 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...

  13. EFFECTS OF CONTINUOUS CHLORINATION ON ENTRAINED ESTUARINE PLANKTON

    Science.gov (United States)

    The effects of continuous chlorination on entrained plankton are investigated in tests using running sea water and adenosine triphosphate (ATP) as an indicator of biomass. Effects were measured by bioluminescence with the use of luciferin-luciferase reagents from firefly lanterns...

  14. Inactivation of human and simian rotaviruses by chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-05-01

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

  15. 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,

  16. Chlorine in the Forest Ecosystem (a Radiotracer Study)

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav

    New York: Nova Science Pub Inc, 2007 - (Lyman, E.), s. 317-331 ISBN 978-1-60021-903-0 R&D Projects: GA ČR GA526/05/0636 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : radiotracer * chlorine * forest ecosystem Subject RIV: DF - Soil Science

  17. Effect of solar electron temperature on pep solar neutrino flux in the chlorine solar neutrino experiment and the gallium solar neutrino experiment

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The rate of the electron-capture reaction of proton,p+e-+p→2H+ve , is calculated considering the temperature of solar electron in the solar center instead of that of solar ion. When the solar electron temperature is two times higher than the solar ion temperature in the solar center, the capture rate pep solar neutrino predicted by the standard solar model (SSM) is decreased to (0.16±0.01) SNU from (0.22±0.01) SNU in the chlorine solar neutrino experiment, and decreased to 2.19 SNU from 3.0 SNU in the gallium solar neutrino experiment.

  18. Electronic diffraction study of the chlorination of nickel; Etude par diffraction electronique de la chloruration du nickel

    Energy Technology Data Exchange (ETDEWEB)

    Vigner, D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    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{sup -4} torr. It has thus been possible to show the very special properties of nickel chloride (CdBr{sub 2} 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) [French] La chloruration des faces (100) (110) et (111) du nickel a ete etudiee par diffraction des electrons de haute energie et par microscopie electronique. Deux methodes ont ete utilisees: le bombardement avec des ions chlore ayant une energie comprise entre 10 et 30 keV, et la chloruration directe dans un diffracteur pour des pressions de l'ordre de 10{sup -4} torr. Ainsi ont ete mises en evidence les proprietes tres particulieres du chlorure de nickel (type CdBr{sub 2}, groupe spatial R 3-bar m) qui s'accole toujours suivant le plan (0001), quelle que soit l'orientation du substrat. Il a ete egalement possible d'atteindre l'interface metal-halogenure et de montrer l'existence de couches chimisorbees bidimensionnelles, ordonnees ou desordonnees suivant l'orientation cristalline etudiee. (auteur)

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

    Science.gov (United States)

    Tabazadeh, A.; Turco, R. P.

    1993-01-01

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

  20. 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

  1. The Chlorine Isotopic Composition Of Lunar UrKREEP

    Science.gov (United States)

    Barnes, J. J.; Tartese, R.; Anand, M.; McCubbin, F. M.; Neal, C. R.; Franchi, I. A.

    2016-01-01

    Since the long standing paradigm of an anhydrous Moon was challenged there has been a renewed focus on investigating volatiles in a variety of lunar samples. Numerous studies have examined the abundances and isotopic compositions of volatiles in lunar apatite, Ca5(PO4)3(F,Cl,OH). In particular, apatite has been used as a tool for assessing the sources of H2O in the lunar interior. However, current models for the Moon's formation have yet to fully account for its thermal evolution in the presence of H2O and other volatiles. For ex-ample, in the context of the lunar magma ocean (LMO) model, it is anticipated that chlorine (and other volatiles) should have been concentrated in the late-stage LMO residual melts (i.e., the dregs enriched in incompatible elements such as K, REEs (Rare Earth Elements), and P, collectively called KREEP, and in its primitive form - urKREEP, given its incompatibility in mafic minerals like olivine and pyroxene, which were the dominant phases that crystallized early in the cumulate pile of the LMO. When compared to chondritic meteorites and terrestrial rocks, lunar samples have exotic chlorine isotope compositions, which are difficult to explain in light of the abundance and isotopic composition of other volatile species, especially H, and the current estimates for chlorine and H2O in the bulk silicate Moon (BSM). In order to better understand the processes involved in giving rise to the heavy chlorine isotope compositions of lunar samples, we have performed a comprehensive in situ high precision study of chlorine isotopes in lunar apatite from a suite of Apollo samples covering a range of geochemical characteristics and petrologic types.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Removal of C.I. Reactive Red 2 by low pressure UV/chlorine advanced oxidation.

    Science.gov (United States)

    Wu, Qianyuan; Li, Yue; Wang, Wenlong; Wang, Ting; Hu, Hongying

    2016-03-01

    Azo dyes are commonly found as pollutants in wastewater from the textile industry, and can cause environmental problems because of their color and toxicity. The removal of a typical azo dye named C.I. Reactive Red 2 (RR2) during low pressure ultraviolet (UV)/chlorine oxidation was investigated in this study. UV irradiation at 254nm and addition of free chlorine provided much higher removal rates of RR2 and color than UV irradiation or chlorination alone. Increasing the free chlorine dose enhanced the removal efficiency of RR2 and color by UV/chlorine oxidation. Experiments performed with nitrobenzene (NB) or benzoic acid (BA) as scavengers showed that radicals (especially OH) formed during UV/chlorine oxidation are important in the RR2 removal. Addition of HCO3(-) and Cl(-) to the RR2 solution did not inhibit the removal of RR2 during UV/chlorine oxidation. PMID:26969069

  7. Occurence of chlorinated aromatic compounds in filter deposits of an incinerator plant for radioactive waste. Pt. 2

    International Nuclear Information System (INIS)

    The catalytic chlorination of chrysene, pyrene and fluoranthene yields complex mixtures of partly isomeric chlorine substituted PAHs. Their distribution resembles that of chlorine compounds previously found in filter deposits of an incineration plant for radioactive waste. In the micro fluctuation test these chlorinated products are strong mutagens to Salmonella typhimurium even without enzymatic activation. Frameshift mutations as well as basepair alterations take place. (Author)

  8. Implantation of methodology for determination of fluorine and chlorine contents in fuel pellets by pyrohydrolysis at CDTN-MG (Brazil)

    International Nuclear Information System (INIS)

    The system and the methodology that were developed to perform fuel pellets quality control at CDTN, in relation to fluorine and chlorine contents by pyrohydrolysis ion-selective electrode method, are shown. The method is based on the separation of these halogens in the presence of wet oxygen, in a temperature ranging from 950 to 1.100 deg C. Fluoride and chloride are volatilized as acids, absorbed in a potassium acetate buffer solution, and measured with ion-selective electrodes. The system was utilized to perform the quality control of uranium dioxide and thorium and uranium mixed oxide fuel pellets, manufactured to research cooperative programs between Brazil and Germany. The obtained results showed that the pellets presented contents of such impurities lower than the maximal limits required by the specifications of these fuels. (author)

  9. Behavior of fluorine and chlorine in Spanish coal fired power plants with pulverized coal boilers and fluidized bed boiler.

    Science.gov (United States)

    López-Vilariño, J M; Fernández-Martínez, G; Turnes-Carou, I; Muinategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

    2003-06-01

    Behavior and contents of fluorine and chlorine in coal feedstock, combustion wastes (slag and fly ash) and emissions were studied in five conventional coal fired power plants and in a fluidized bed coal power plant. The halide levels found in the used coal were quite low. Mass balances and emission factors were calculated. The volatility of these elements makes the gaseous emission the main target between the residues. The influence of combustion parameters is not clearly established. Several analytical techniques (ion selective electrodes, capillary electrophoresis and ion chromatography) are employed to determinate the halide concentration in the different samples taken in the power plants studied (coal, slag, fly ash and flue gases). PMID:12868523

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

    Science.gov (United States)

    Yang, Xin; Guo, Wanhong; Lee, Wontae

    2013-06-01

    Chlorine dioxide (ClO2) is often used as an oxidant to remove taste, odor and color during water treatment. Due to the concerns of the chlorite formation, chlorination or chloramination is often applied after ClO2 preoxidation. We investigated the formation of regulated and emerging disinfection byproducts (DBPs) in sequential ClO2-chlorination and ClO2-chloramination processes. To clarify the relationship between the formation of DBPs and the characteristics of natural organic matter (NOM), changes in the properties of NOM before and after ClO2 oxidation were characterized by fluorescence, Fourier transform infrared spectroscopy (FTIR), and size and resin fractionation techniques. ClO2 preoxidation destroyed the aromatic and conjugated structures of NOM and transformed large aromatic and long aliphatic chain organics to small and hydrophilic organics. Treatment with ClO2 alone did not produce significant amount of trihalomethanes (THMs) and haloacetic acids (HAAs), but produced chlorite. ClO2 preoxidation reduced THMs, HAAs, haloacetonitriles (HANs) and chloral hydrate (CH) during subsequent chlorination, but no reduction of THMs was observed during chloramination. Increasing ClO2 doses enhanced the reduction of most DBPs except halonitromethanes (HNMs) and haloketones (HKs). The presence of bromide increased the formation of total amount of DBPs and also shifted DBPs to more brominated ones. Bromine incorporation was higher in ClO2 treated samples. The results indicated that ClO2 preoxidation prior to chlorination is applicable for control of THM, HAA and HAN in both pristine and polluted waters, but chlorite formation is a concern and HNMs and HKs are not effectively controlled by ClO2 preoxidation. PMID:23312737

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

    Energy Technology Data Exchange (ETDEWEB)

    Eikeland, Marianne Soerflaten

    2001-03-01

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

  12. Physico-chemical behaviour of a metal/polymer contact subject to a low amplitude friction in a chlorinated medium. Effect of ionitriding and ion implantation surface treatment; Comportement physico-chimique d`un contact metal/polymere soumis a un frottement sous petits debattements en milieu chlorure. Influence des traitements de surface par implantation et nitruration ioniques

    Energy Technology Data Exchange (ETDEWEB)

    Rabbe, L.M.

    1993-10-01

    The fretting-corrosion behaviour of two tribological couples (TA6V/PMMA and 316L/PMMA) had been studied in order to better understand the degradation mechanisms observed on pivot prosthesis sealed in bones. Pressure appears to have a major role; at high contact pressure, the PMMA wear is the main degradation mechanism with PMMA debris acting as a metal surface protecting agent; at low contact pressure, both material deterioration is involved, and titanium has a corrosion-dominated degradation. An optimal resistance to fretting is achieved when TA6V is coated with Ti N (ion implantation) and Ti N, Ti{sub 2} N (ionitriding). When nitriding, processing temperature appears as a critical factor to ensure thickness and homogeneity of the nitride coatings. 181 p., 106 figs., 110 refs.

  13. 双掺粉煤灰和矿粉的海工混凝土抗氯离子性能试验分析%Experimental study for the chlorine ion penetration resistant performance of marine concrete mixed with fly ash and slag powder

    Institute of Scientific and Technical Information of China (English)

    吴毅峰

    2012-01-01

    The appropriative addition of mineral admixture can improve compactness, resistivity and durability of concrete. This pa- per studied the effects of water--binder ratio, content of fly ash, content of slag and sand-ratio on the chloride ions impermeabili- ty resistant performance of marine concrete based on orthogonal experiment using intuitive analysis. According to the experiments,the optimal content of fly ash and slag ash to improve chloride ions impermeability resistant performance of concrete has been sug- gested and it can provide reference for the mix design of marine concrete.%在混凝土中掺加适当的掺合料能提高混凝土的密实性,增加混凝土的电阻率,有效提高混凝土的耐久性,本文通过正交试验及直观分析法研究混凝土配合比参数(水胶比、粉煤灰掺量、矿粉掺量和砂率)对不同龄期海工混凝土抗氯离子渗透性能的影响趋势。通过试验分析,给出了最佳粉煤灰和矿粉掺量以提高海工混凝土的抗氯离子渗透性能,为海工混凝土配合比设计提供参考。

  14. Determination of chlorine, fluorine, bromine, and iodine in coals with ICP-MS and IC

    Energy Technology Data Exchange (ETDEWEB)

    Bettinelli, M.; Spezia, S.; Minoia, C.; Ronchi, A. [Salvatore Maugeri Foundation, Pavia (Italy)

    2002-07-01

    The combustion process releases many organic and inorganic pollutants into the atmosphere, both in gaseous and solid form. During coal combustion in thermal power plants without pollution control equipment, chlorine, fluorine, bromine, and iodine present in coals are mainly volatilized as gaseous compounds. Limiting pollutant emissions is a precise requirement of the Italian legislation that fixes (in the case of power plants) 100 mg/Nm{sup 3} as the limit value for chlorine, and 5 mg/Nm{sup 3} for fluorine and bromine (expressed as hydrofluoric and hydrobromic acid respectively). No limit for iodine emissions has been established. From this point of view and in order to maintain control of emissions from combustion plants, it is important to monitor the concentration of halogens in fuels. Unfortunately, in literature there are very few data published with regard to the amount of halogens in fossil fuels, which emphasizes the analytical difficulties with regard to the determination of these analytes. In the present paper a, pyrohydrolysis of the sample at 1100{degree}C, followed by the absorption of volatilized compounds in Na{sub 2}CO{sub 3}/NaHCO{sub 3} solution and the final instrumental analysis of Cl, Br, and F with ion chromatography (IC) and Br and I with inductively coupled plasma mass spectrometry (ICP-MS) has been adopted. The accuracy of the method, evaluated by analyzing some certified reference materials, was better than 95% for all analytes and the detection limits adequate to the analytical requirements (0.1 mg/kg for Br and I, 1 mg/kg for F, and 10 mg/kg for C1).

  15. The Solar Flare Chlorine Abundance from RESIK X-ray Spectra

    CERN Document Server

    Sylwester, B; Sylwester, J; Kuznetsov, V D

    2011-01-01

    The abundance of chlorine is determined from X-ray spectra obtained with the RESIK instrument on {\\em CORONAS-F} during solar flares between 2002 and 2003. Using weak lines of He-like Cl, \\ion{Cl}{16}, between 4.44 and 4.50 \\AA, and with temperatures and emission measures from {\\em GOES} on an isothermal assumption, we obtained $A({\\rm Cl}) = 5.75 \\pm 0.26$ on a scale $A({\\rm H}) = 12$. The uncertainty reflects an approximately factor 2 scatter in measured line fluxes. Nevertheless our value represents what is probably the best solar determination yet obtained. It is higher by factors of 1.8 and 2.7 than Cl abundance estimates from an infrared sunspot spectrum and nearby \\ion{H}{2} regions. The constancy of the RESIK abundance values over a large range of flares ({\\em GOES} class from below C1 to X1) argues for any fractionation that may be present in the low solar atmosphere to be independent of the degree of solar activity.

  16. Highly chlorinated unintentionally produced persistent organic pollutants generated during the methanol-based production of chlorinated methanes: A case study in China.

    Science.gov (United States)

    Zhang, Lifei; Yang, Wenlong; Zhang, Linli; Li, Xiaoxiu

    2015-08-01

    The formation of unintentionally produced persistent organic pollutants (POPs) may occur during various chlorination processes. In this study, emissions of unintentionally produced POPs during the methanol-based production of chlorinated methanes were investigated. High concentrations of highly chlorinated compounds such as decachlorobiphenyl, octachloronaphthalene, octachlorostyrene, hexachlorobutadiene, hexachlorocyclopentadiene, hexachlorobenzene, and pentachlorobenzene were found in the carbon tetrachloride byproduct of the methanol-based production of chlorinated methanes. The total emission amounts of hexachlorocyclopentadiene, hexachlorobutadiene, polychlorinated benzenes, polychlorinated naphthalenes, octachlorostyrene, and polychlorinated biphenyls released during the production of chlorinated methanes in China in 2010 were estimated to be 10080, 7350, 5210, 427, 212, and 167 kg, respectively. Moreover, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) were formed unintentionally during chlorinated methanes production, the emission factor for PCDDs/DFs was 364 μg toxic equivalency quotient (TEQ) t(-1) product for residues, which should be added into the UNEP toolkit for updating. It was worth noting that a high overall toxic equivalency quotient from polychlorinated naphthalenes and PCDDs/DFs was generated from the chlorinated methanes production in China in 2010. The values reached 563 and 32.8 g TEQ, respectively. The results of the study indicate that more research and improved management systems are needed to ensure that the methanol-based production of chlorinated methanes can be achieved safely. PMID:25777670

  17. Synthesis and properties of new chlorin and bacteriochlorin photosensitizers

    Science.gov (United States)

    Mironov, Andrei F.

    1996-01-01

    A series of novel sensitizers, which absorb in the range of 660 - 820 nm, derived from natural occurring chlorophyll and bacteriochlorophyll was synthesized. Biomass of blue-green algae Spirulina platensis was used to prepare chlorophyll a derivatives, and biomass of purple bacteria Rhodobacter capsulatus was applied for preparation of bacteriochlorophyll a. The influence of different substituents on spectral characteristics and the amphipility of the sensitizer was investigated. The route for the synthesis of porphyrin macrocycle with the spacer that bears the isothiocyanate group capable for binding with proteins was proposed. Photophysical properties of chlorin p6, purpurin 18 and their esters in different solvents are investigated. Accumulation of two chlorins in the model Erlich tumor was studied.

  18. Second-generation photosensitizers based on natural chlorines and bacteriochlorines

    Science.gov (United States)

    Mironov, Andrei F.

    1996-01-01

    New sensitizers for photodynamic therapy were synthesized on the base of biologically generated chlorins and bacteriochlorins. Derivatives of chlorophyll a and bacteriochlorophyll were prepared from the biomass of blue-green algae Spirulina Platensis and purple bacteria Rhodobacter Capsulatus, generated using specially designed photobioreactor. The strategy for chemical transformation of natural chlorophylls and bacteriochlorophyll has been discussed. Purpurin 18 and its dihydroanalogue bacteriopurpurin were chosen as the key intermediates. Modifications of peripheral substituents, such as introducing the new functional groups, hydrogenation of the B-pyrrolic ring, and insertion of amino acid residues gave the series of novel sensitizers, including water soluble chlorin p6 analogues, and derivatives with graded amphiphility for the studies of tumor accumulation in the malignant tissues.

  19. 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

  20. 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.

  1. Effect of odd hydrogen on ozone depletion by chlorine reactions

    Science.gov (United States)

    Donahue, T. M.; Cicerone, R. J.; Liu, S. C.; Chameides, W. L.

    1976-01-01

    The present paper discusses how the shape of the ozone layer changes under the influence of injected ClX for several choices of two key HOx reaction rates. The two HOx reactions are: OH + HO2 yields H2O + O2 and O + HO2 yields OH + O2. Results of calculations are presented which show that the two reaction rates determine the stratospheric concentrations of OH and HO2, and that these concentrations regulate the amount by which the stratospheric ozone column can be reduced due to injections of odd chlorine. It is concluded that the amount of ozone reduction by a given mixing ratio of ClX will remain very uncertain until the significance of several possible feedback effects involving HOx in a chlorine-polluted atmosphere are determined and measurements of the reaction rates and HOx concentrations are made at the relevant temperatures.

  2. Field-usable portable analyzer for chlorinated organic compounds

    International Nuclear Information System (INIS)

    In 1992, a chemical sensor was developed which showed almost perfect selectivity to vapors of chlorinated solvents. When interfaced to an instrument, a chemical analyzer will be produced that has near- absolute selectivity to vapors of volatile chlorinated organic compounds. TRI has just completed the second of a 2-phase program to develop this new instrument system, which is called the RCL MONITOR. In Phase II, this instrument was deployed in 5 EM40 operations. Phase II applications covered clean-up process monitoring, environmental modeling, routine monitoring, health and safety, and technology validation. Vapor levels between 0 and 100 ppM can be determined in 90 s with a lower detection limit of 0.5 ppM using the hand-portable instrument. Based on the favorable performance of the RCL MONITOR, the commercial instrument was released for commercial sales on Sept. 20, 1996

  3. Intrinsic bioremediation of chlorinated hydrocarbons at cold temperatures

    International Nuclear Information System (INIS)

    This paper describes a study of the viability of intrinsic bioremediation of chlorinated aromatic hydrocarbons at cold temperatures, at a former landfill site, some 300 km northeast of Edmonton. The landfill was also used for disposing of various hydrocarbon-based products of environmental concern.The project was conducted in four phases, i. e. site investigation, analysis of contaminant concentration, microbial study in the laboratory, and computer fate and transport modeling, with the primary focus being on the effect of cold temperatures on the rate of reductive dechlorination. Preliminary analysis of the results shows considerable evidence for the biodegradation of chlorinated hydrocarbons and confirms intrinsic bioremediation as a viable option for cold temperature sites. 20 refs., 7 figs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1963-07-01

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

  5. 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

  6. Gas Phase Sulfur, Chlorine and Potassium Chemistry in Biomass Combustion

    DEFF Research Database (Denmark)

    Løj, Lusi Hindiyarti

    2007-01-01

    Gas Phase Sulfur, Chlorine and Alkali Metal Chemistry in Biomass Combustion Concern about aerosols formation, deposits, corrosion, and gaseous emissions during biomass combustion, especially straw, continues to be a driving force for investigation on S, Cl, K-containing species under combustions...... uncertainties. In the present work, the detailed kinetic model for gas phase sulfur, chlorine, alkali metal, and their interaction has been updated. The K/O/H/Cl chemistry, S chemistry, and their interaction can reasonably predict a range of experimental data. In general, understanding of the interaction...... sulfur chemistry important for the SO2/SO3 ratio under combustion conditions has been updated. The uncertainties of the important rate constants have been minimized. Modeling predictions with a revised reaction mechanism for SO2/SO3 chemistry are in a good agreement with a range of experimental data from...

  7. MECHANISM OF CHLORATE FORMATION IN CHLORINE DIOIXDE DELIGNIFICATION

    Institute of Scientific and Technical Information of China (English)

    Byung-HoYoon; Li-JunWangI; Se-JongKim

    2004-01-01

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

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

    Directory of Open Access Journals (Sweden)

    V. Zitko

    2001-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wu Xianglong [Key Laboratory For Space Bioscience and Biotechnology, Faculty of Life Sciences, Northwestern Polytechnical University, Xi' an 710072 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry and Materials Science, Northwest University, Tai Bai Bei Lu 229, Xi' an 710069, Shaanxi (China); Jin Xilang; Wang Yunxia [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry and Materials Science, Northwest University, Tai Bai Bei Lu 229, Xi' an 710069, Shaanxi (China); Mei Qibing [Key Laboratory For Space Bioscience and Biotechnology, Faculty of Life Sciences, Northwestern Polytechnical University, Xi' an 710072 (China); Li Jianli, E-mail: lijianli@nwu.edu.c [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry and Materials Science, Northwest University, Tai Bai Bei Lu 229, Xi' an 710069, Shaanxi (China); Shi Zhen, E-mail: gahpyudx@163.co [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry (Ministry of Education), College of Chemistry and Materials Science, Northwest University, Tai Bai Bei Lu 229, Xi' an 710069, Shaanxi (China)

    2011-04-15

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

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

    Science.gov (United States)

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

    2016-05-01

    The co-exposure to UV irradiation and free chlorine may occur in certain drinking water and wastewater treatment systems. This study investigated the effects of simultaneous low pressure ultraviolet (LPUV) irradiation and free chlorination on the formation of chloroform from triclosan which is a commonly used antibacterial agent. Different treatment systems (i.e., combined UV/chlorine, UV alone, and chlorine alone) were applied to examine the degradation of triclosan and formation of chloroform. The fate of representative intermediates, including chlorinated triclosan, dechlorinated triclosan intermediates and 2,4-dichlorophenol, were tracked to deduce the effect of combined UV/chlorine on the transformation of chloroform formation precursors. The relation between intermediates degradation and chloroform formation was investigated in depth by conducting stepwise experiments with UV and chlorine in different sequences. Results indicate that the combined UV/chlorine notably enhanced the chloroform formation from triclosan. From the reaction mechanism perspective the combined UV/chlorine, where the direct photolysis may play an important role, could accelerate the decay of intermediates and facilitate the generation of productive chloroform precursors. The radicals had modest influence on the degradation of triclosan and intermediates and partly hindered the formation of chloroform. These results emphasize the necessity of considering disinfection by-products formation in the application of combined UV/chlorine technology during water treatment. PMID:26746417

  11. Heat inactivation of Escherichia coli O157:H7 in apple juice exposed to chlorine.

    Science.gov (United States)

    Folsom, J P; Frank, J F

    2000-08-01

    Exposure of Escherichia coli O157:H7 to chlorine before heat treatment results in increased production of heat shock proteins. Current heating regimens for pasteurizing apple cider do not account for chlorine exposure in the wash water. This research determined the effect of sublethal chlorine treatment on thermal inactivation of E. coli O157:H7. D58-values were calculated for stationary-phase cells exposed to 0.6 mg/liter of total available chlorine and unchlorinated cells in commercial shelf-stable apple juice (pH 3.6). D58-values for unchlorinated and chlorine-exposed cells in buffer were 5.45 and 1.65 min, respectively (P D58-values calculated from these populations are 0.77 min for unexposed cells and 1.19 min for chlorine-exposed cells (P = 0.05). This indicates that a subpopulation of chorine-treated cells is possibly more resistant to heat because of chlorine treatment. The effect of chlorine treatment, however, is insignificant when compared with the effect of losing the shoulder. This is illustrated by the time required to kill the initial 90% of the cell population. This is observed to be 3.14 min for unchlorinated versus 0.3 min for chlorine-exposed cells (P < 0.001). These observations indicate that current heat treatments need not be adjusted for the effect of chlorine treatment. PMID:10945574

  12. Pandora's Poison: Chlorine, Health, and a New Environmental Strategy

    OpenAIRE

    THORNTON, J.

    2002-01-01

    This book focuses on a group of chemicals, organochlorines, that tops the list of all global and environmental contaminants. The author analyzes the cause and effects of problems associated with producing chlorine-based substances. The book examines organochlorines by looking at major sources, the health impacts on humans and wildlife, and its relation to cancer. The author concludes by suggesting policies and alternatives that can reduce the negative impact of organochlorines.

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

    OpenAIRE

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

    2008-01-01

    The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant...

  14. [Action modes of chlorine dioxide--a review].

    Science.gov (United States)

    Wei, Mingken; Lai, Jieling; Zhan, Ping

    2012-04-01

    Chlorine dioxide (ClO2) is a highly effective disinfectant for food and potable water treatment. Till now, the action mode of ClO2 is still unclear. ClO2, can denature proteins by oxidizing tyrosine, tryptophan, and cysteine. We reviewed the pathways by which ClO02 reacts with important bio-molecules, as well as the primary target sites at individual cellular level of ClO2-induced biocidal effects. PMID:22799207

  15. Comparative Analytical Methods for the Measurment of Chlorine Dioxide

    OpenAIRE

    Desai, Unmesh Jeetendra

    2002-01-01

    Four commercially available methods used for the analysis of low-level Chlorine Dioxide (ClO2) concentrations in drinking water were evaluated for accuracy and precision and ranked according to cost, efficiency and ease of the methods under several conditions that might be encountered at water treatment plants. The different analytical methods included: 1.The DPD (N, N-diethyl-p-phenylenediamine) method 2.Lissamine Green B (LGB) wet-chemical method 3.Palintest® kit LGB 4.A...

  16. Plasma chemical etching of gallium arsenide in chlorine

    International Nuclear Information System (INIS)

    One of the most promising methods, used for the examination of the kinetics and determination of the moments of the start and completion of the processes of plasma chemical etching of a wide range of inorganic materials is optical emission spectroscopy. Therefore, the aim of this work was to examine the kinetic relationships of etching of gallium arsenide in chlorine plasma and determine the possibilities of the optical emission spectroscopy for examination and control of the process

  17. Chlorine Dioxide Gas Sterilization under Square-Wave Conditions

    OpenAIRE

    Jeng, David K.; Woodworth, Archie G.

    1990-01-01

    Experiments were designed to study chlorine dioxide (CD) gas sterilization under square-wave conditions. By using controlled humidity, gas concentration, and temperature at atmospheric pressure, standard biological indicators (BIs) and spore disks of environmental isolates were exposed to CD gas. The sporicidal activity of CD gas was found to be concentration dependent. Prehumidification enhanced the CD activity. The D values (time required for 90% inactivation) of Bacillus subtilis subsp. ni...

  18. 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.

  19. The pool chlorine hypothesis and asthma among boys.

    LENUS (Irish Health Repository)

    Cotter, A

    2012-01-31

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

  20. The role of natural chlorinated hydroquinone metabolites in ligninolytic fungi

    OpenAIRE

    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), 2,6-dichloro-1,4-dimethoxybenzene (26DCl-14DMB), tetrachloro-1,4-dimethoxybenzene and tetrachloro-4-methoxyphenol, which are synthesized by 11 genera of Basidiomycetes.The biosynthesis of these chlor...

  1. Solubility of chlorine in aqueous hydrochloric acid solutions.

    Science.gov (United States)

    Alkan, Mahir; Oktay, Münir; Kocakerim, M Muhtar; Copur, Mehmet

    2005-03-17

    The solubility of chlorine in aqueous hydrochloric acid solutions was studied. The effects of HCl concentration and temperature on the solubility were evaluated, and the thermodynamic parameters of the dissolution were calculated. It was found that the solubility isotherms had a minimum at about 0.5M HCl concentration at all the temperatures studied and that solubility decreased with the increase of temperature at all the HCl concentration range investigated. PMID:15752843

  2. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

    Energy Technology Data Exchange (ETDEWEB)

    Grisham, L. R.; Kwan, J. W.

    2008-08-01

    Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

  3. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy, and Related Fields

    International Nuclear Information System (INIS)

    Some years ago it was suggested that halogen negative ions (1)could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion-ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component--positive ions, negative ions, and electrons--can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion-ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed

  4. Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

    International Nuclear Information System (INIS)

    Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, and with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.

  5. Manganese chlorins immobilized on silica as oxidation reaction catalysts.

    Science.gov (United States)

    Castro, Kelly A D F; Pires, Sónia M G; Ribeiro, Marcos A; Simões, Mário M Q; Neves, M Graça P M S; Schreiner, Wido H; Wypych, Fernando; Cavaleiro, José A S; Nakagaki, Shirley

    2015-07-15

    Synthetic strategies that comply with the principles of green chemistry represent a challenge: they will enable chemists to conduct reactions that maximize the yield of products with commercial interest while minimizing by-products formation. The search for catalysts that promote the selective oxidation of organic compounds under mild and environmentally friendly conditions constitutes one of the most important quests of organic chemistry. In this context, metalloporphyrins and analogues are excellent catalysts for oxidative transformations under mild conditions. In fact, their reduced derivatives chlorins are also able to catalyze organic compounds oxidation effectively, although they have been still little explored. In this study, we synthesized two chlorins through porphyrin cycloaddition reactions with 1.3-dipoles and prepared the corresponding manganese chlorins (MnCHL) using adequate manganese(II) salts. These MnCHL were posteriorly immobilized on silica by following the sol-gel process and the resulting solids were characterized by powder X-ray diffraction (PXRD), UVVIS spectroscopy, FTIR, XPS, and EDS. The catalytic activity of the immobilized MnCHL was investigated in the oxidation of cyclooctene, cyclohexene and cyclohexane and the results were compared with the ones obtained under homogeneous conditions. PMID:25841060

  6. Rapid infrared determination of the potency of chlorinated bactericides.

    Science.gov (United States)

    Spagnolo, F; Cestaro, J P

    1971-06-01

    A rapid infrared reflectance method for evaluating the germicidal potency of synthetic materials containing various amounts of two chlorinated bactericides was developed. The dimeric product 2,2'-methylenebis (4,6-dichlorophenol) exhibited a characteristic C=C skeletal inplane stretching infrared absorption band at 1,640 cm(-1). The monomeric 2,4-dichlorophenol precursor showed a characteristic absorption band at 1,579 cm(-1). These characteristic infrared absorptions may be used for analysis of the potency of the manufactured chlorinated bactericide. For a series of samples known to vary in dimer content, the micrograms per milliliter required for a 100% bacterial kill is first determined by a standard American Petroleum Institute method. Then the area ratio of the infrared absorption bands characteristic of the chlorinated bactericides is measured for each sample and plotted versus the microgram per milliliter required for 100% bacterial kill. The potency of subsequent samples is simply and rapidly determined by measuring this ratio from the infrared absorption curve and calculating micrograms per milliliter required for 100% kill from the calibration curve. Analysis time is approximately 1 hr compared to biocidal tests in current use requiring approximately a 1-month incubation period. PMID:5564677

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

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2007-03-01

    Full Text Available Equivalent effective stratospheric chlorine (EESC is a convenient parameter to quantify the effects of halogens (chlorine and bromine on ozone depletion in the stratosphere. We show and discuss a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. Using this EESC formulation, we estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties in the estimated time of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air, and the assumption that the mean age-of-air and fractional release values are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be accelerated from 2041 to 2031.

  8. 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.

  9. 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.

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

    CERN Document Server

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

    2014-01-01

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

  11. Detection of chlorinated methanes by tin oxide gas sensors.

    Science.gov (United States)

    Park, S H; Son, Y C; Shaw, B R; Creasy, K E; Suib, S L

    2001-08-01

    Tin oxide thin films prepared by thermal oxidation of Sn films were used for the detection of chlorinated methanes (CH2Cl2, CHCl3 and CCl4). This resulted in better chemical selectivity, sensitivity, response speed and detection limit than seen with previous detectors. The temperature dependence of the sensing of 1% CCl4 gas was studied and the best sensing behavior was observed at 300 degrees C. The films showed different chemical selectivity in both speed and direction of sensing response to each gas and were stable for more than 3 weeks under operating conditions. The films showed rapid gas sensing (<40 s to reach 90% of full response) and low detection limits (< 4 ppm CCl4). The role of oxygen in the detection of chlorinated methanes and in resistance changes without chlorinated methanes was also studied. The changes at the surface of the film after gas sensing were examined using scanning electron microscopy with energy-dispersive X-ray spectrometry. PMID:11534610

  12. Sem-edx and ftir studies of chlorinated rubber coating

    International Nuclear Information System (INIS)

    Summary: Anticorrosive performance of chlorinated rubber coating has been investigated by visual examination, Scanning electron microscopy (SEM)/Energy dispersive X-ray (EDX) analysis and Fourier transform infrared (FTIR) spectroscopy. After surface preparation, commercially available coating system based on chlorinated rubber (primer)/chlorinated rubber (topcoat) formulation was applied on mild steel test panels (10cm x 15cm sizes). Prepared coated panels were exposed at marine, industrial and urban test sites located in Karachi, Pakistan according to ISO 8565 norm. Accelerated testing was performed by using a salt spray chamber (ASTM B117 norm). Accelerated weathering methods are the methods in which the factors responsible for the degradation of coatings are artificially intensified in order to achieve the rapid degradation of coatings. Visual examination of blistering and rusting as well as SEM micrographs indicated a more severe degradation of the coating surface characteristics at natural exposure testing sites (particularly at marine test site) than for accelerated (salt spray) testing. EDX determination of the Oxygen/Carbon (O/C) ratios also indicated increased degradation at natural test sites compared to the accelerated (salt spray) testing. Photooxidation of the binder results in the formation of carbonyl compounds as revealed by FTIR spectroscopy which also indicated dehydrochlorination. (author)

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

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    2011-04-01

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

  14. 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.; Sundin, P.; Wesen, C.

    2004-01-01

    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...... 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...

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  16. Increased toxicity of textile effluents by a chlorination process using sodium hypochlorite.

    Science.gov (United States)

    Chen, C M; Shih, M L; Lee, S Z; Wang, J S

    2001-01-01

    Chlorinated textile effluents were tested for their toxicity using different bioassays. These assays were the Microtox assay, daphnia (Daphnia similis) 48-hr survival test, medaka embryo 14-day and juvenile 96-hr survival tests, and tilapia (Oreochromis mossambicus) juvenile 96-hr survival test. By comparing the results of toxicity tests on water samples collected at the instream prior to the chlorination process and at the outlet of the wastewater treatment facility, we found that wastewater toxicity was obviously increased by chlorination using NaOCl as the oxidant, as evidenced by the different bioassays used. Because no significant difference was observed in water chemistry, such as pH, DO, and conductivity, the induced-toxicity may be partially attributable to residue chlorine or other chlorinated compounds generated by chlorination. Future studies are warranted to identify the cause of the increase in the textile wastewater toxicity. PMID:11380166

  17. 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

  18. 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

  19. Effect of turbidity on chlorination efficiency and bacterial persistence in drinking water.

    OpenAIRE

    LeChevallier, M. W.; Evans, T. M.; Seidler, R J

    1981-01-01

    To define interrelationships between elevated turbidities and the efficiency of chlorination in drinking water, experiments were performed to measure bacterial survival, chlorine demand, and interference with microbiological determinations. Experiments were conducted on the surface water supplies for communities which practice chlorination as the only treatment. Therefore, the conclusions of this study apply only to such systems. Results indicated that disinfection efficiency (log10 of the de...

  20. Investigation of chlorination of zirconium and hafnium and their compounds in discharge from hollow cathode

    International Nuclear Information System (INIS)

    The possibility is investigated of chlorinating various zirconium and hafnium compounds (metal, oxide, carbide) in a hot discharge from a hollow cathode with various chlorinating reagents: copper monochloride, nickel chloride, magnesium chloride, for the purpose of accelerating their entrance into the excitation zone. It has been shown thermodynamically and experimentally that chlorination of metal zirconium and hafnium and their carbides with copper monochloride in hot hollow cathode conditions provides a sharp increase in the intensity of the lines of these elements

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

    OpenAIRE

    Kátia Maria Morais Eiras; Jorge Luiz Colodette; Vanessa Lopes Silva

    2009-01-01

    Our previous paper showed fragmentary evidence that pulp brightness reversion may be negatively affected by its organically bound chlorine (OX) content. A thorough investigation on eucalyptus kraft pulp led to the conclusion that OX increases reversion of certain pulps but this trend is not universal. Alkaline bleaching stages decrease reversion regardless of pulp OX content. Pulps bleached with high temperature chlorine dioxide revert less than those bleached with conventional chlorine dioxi...

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

    OpenAIRE

    Drdla, K.; Müller, R.

    2012-01-01

    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...

  3. Chlorine dioxide by-products in drinking water and their control by powdered activated carbon

    OpenAIRE

    Grabeel, Margaret N.

    1992-01-01

    The concentrations of chlorine dioxide (CI02), chlorine, chlorite (CIO2), and chlorate (CI03) were evaluated following pretreatment of raw water by CI02 at water treatment plants in New Castle, Pennsylvania; Charleston, West Virginia; Skagit, Washington; and Columbus, Georgia. Chlorite and chlorate concentrations were unaffected by any of the water treatment processes and did not vary as a function of time of travel in the distribution system. Chlorine dioxide, which was ana...

  4. Oxidation of diclofenac with chlorine dioxide in aquatic environments: influences of different nitrogenous species.

    Science.gov (United States)

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Ni, Tianjun

    2015-06-01

    The oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug and emerging water pollutant, with chlorine dioxide was investigated under simulated water disinfection conditions. The reaction kinetics as functions of the initial concentrations of DCF, different nitrogenous species, and different pE values were experimentally determined. The results demonstrated that DCF reacted rapidly with ClO2, where more than 75 % of DCF (≤3.00 μM) was removed by 18.94 μM ClO2 within 60 s. All of the reactions followed pseudo first-order kinetics with respect to DCF, and the rate constant, k obs, exhibited a significant decrease from 4.21 × 10(-2) to 8.09 × 10(-3) s(-1), as the initial DCF concentration was increased from 1.00 to 5.00 μM. Furthermore, the degradation kinetics of DCF was clearly dependent on nitrogen-containing ion concentrations in the reaction solution. Ammonium and nitrite ions inhibited the DCF degradation by ClO2, whereas nitrate ion clearly initiated its promotion. In contrast, the inhibitory effect of NO2 (-) was more robust than that of NH4 (+). When the values of pE were gradually increased, the transformation of NH4 (+) to NO2 (-), and subsequently to NO3 (-), would occur, the rate constants were initially decreased, and then increased. When NH4 (+) and NO2 (-) coexisted, the inhibitory effect on the DCF degradation was less than the sum of the partial inhibitory effect. However, when NO2 (-) and NO3 (-) coexisted, the actual inhibition rate was greater than the theoretical estimate. These results indicated that the interaction of NH4 (+) and NO2 (-) was antagonistic, while the coexistence of NO2 (-) and NO3 (-) was observed to have a synergistic effect in aqueous environments. PMID:25604564

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

    Directory of Open Access Journals (Sweden)

    Kátia Maria Morais Eiras

    2009-01-01

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

  6. Dealing with the chlorinated solvent situation at the Oak Ridge Y-12 Plant

    International Nuclear Information System (INIS)

    Recent events regarding health and environmental problems associated with the use of chlorinated solvents have prompted the Oak Ridge Y-12 Plant to investigate substitutes for these materials. Since 1987, the purchase of chlorinated solvents at the Y-12 Plant has been reduced by 92%. This has been accomplished by substituting chlorinated solvent degreasing with ultrasonic aqueous detergent cleaning and by substituting chlorinated solvents with less toxic, environmentally friendly solvents for hand-wiping applications. Extensive studies of cleaning ability, compabitility, and effects on welding, bonding, and painting have been conducted to gain approval for use of these solvents. Toxicity and waste disposal were also assessed for the solvents

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-03-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    KAUST Repository

    Nihemaiti, Maolida

    2014-05-01

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

  11. Transfer of chlorine from the environment to agricultural foodstuffs

    International Nuclear Information System (INIS)

    The factors governing chlorine transfer from Phaeozem and Greyzem soils to various important crop species (foodstuff and forage) were determined in natural conditions in the Kiev region of Ukraine. The stable chlorine concentration ratio (CR) values were the lowest in apple (0.5 ± 0.3) and strawberry (2 ± 1), higher in vegetables (5 ± 3), seeds (15 ± 7) and reached a maximum in straw (187 ± 90). The average CR values of 36Cl were estimated for the most important crops using all experimental data on 36Cl and stable chlorine transfer into plants from various soils. It was experimentally shown that boiling potatoes in water leads to an equilibrium between 36Cl specific content in the water and moisture in the cooked potato. The 36Cl processing factor (PF) for boiling various foodstuffs is equal to the ratio of water mass in the cooked foodstuff to the total water mass (in the food and the decoction). 36Cl PF for cereal flour can be estimated as 1. The 36Cl processing factor for dairy products is equal to the ratio of residual water mass in the product to initial water mass in milk. At a 36Cl specific activity in soil of 1 Bq kg-1, the estimated annual dietary 36Cl intake into human organism (adult man) is about 10 kBq. Sixty to seventy percent of the above amount will be taken in via milk and dairy products, 7-16% via meat, 14-16% via bread and bakery items and 8-12% via vegetables. The highest annual 36Cl intake, 10.7 kBq, is predicted for 1-year-old children. The expected effective doses from annual 36Cl intake are higher for younger age groups, increasing from 0.008 mSv in adults to 0.12 mSv in 1-year-old children

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

    Directory of Open Access Journals (Sweden)

    P. A. Newman

    2007-09-01

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

  13. 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.

  14. 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.

  15. Comparative toxicity of new halophenolic DBPs in chlorinated saline wastewater effluents against a marine alga: halophenolic DBPs are generally more toxic than haloaliphatic ones.

    Science.gov (United States)

    Liu, Jiaqi; Zhang, Xiangru

    2014-11-15

    Using seawater for toilet flushing effectively reduces the consumption of precious freshwater resources, yet it introduces bromide and iodide ions into a wastewater treatment system, which may form bromo- and iodo-disinfection byproducts (DBPs) during chlorination of the wastewater effluent. Most of the newly identified DBPs in chlorinated wastewater effluents were halophenolic compounds. It has been reported that the newly identified bromo- and iodo-phenolic DBPs were generally significantly more toxic to a heterotrophic marine polychaete than the commonly known haloacetic acids and trihalomethanes. This has raised a concern over the discharge of chlorinated saline wastewater effluents into the marine ecosystem. In this study, the toxicity of new halophenolic DBPs and some haloaliphatic DBPs was tested against an autotrophic marine alga, Tetraselmis marina. The alga and polychaete bioassays gave the same toxicity orders for many groups of halo-DBPs. New halophenolic DBPs also showed significantly higher toxicity to the alga than the commonly known haloacetic acids, indicating that the emerging halophenolic DBPs deserve more attention. However, two bioassays did exhibit a couple of disparities in toxicity results, mainly because the alga was capable of metabolizing some (nitrogenous) halophenolic DBPs. A quantitative structure-toxicity relationship was developed for the halophenolic DBPs, by employing three physicochemical descriptors (log K(ow), pKa and molar topological index). This relationship presented the toxicity mechanism of the halophenolic DBPs to T. marina and gave a good prediction of the algal toxicity of the tested halophenolic DBPs. PMID:25090624

  16. Distributions and fate of chlorinated pesticides, biomarkers and polycyclic aromatic hydrocarbons in sediments along a contamination gradient from a point-source in San Francisco Bay, California

    Science.gov (United States)

    Pereira, W.E.; Hostettler, F.D.; Rapp, J.B.

    1996-01-01

    The distribution and fate of chlorinated pesticides, biomarkers, and polycyclic aromatic hydrocarbons (PAHs) in surficial sediments along a contamination gradient in the Lauritzen Canal and Richmond Harbor in San Francisco Bay was investigated. Compounds were identified and quantified using gas chromatography-ion trap mass spectrometry. Biomarkers and PAHs were derived primarily from weathered petroleum. DDT was reductively dechlorinated under anoxic conditions to DDD and several minor degradation products, DDMU, DDMS, and DDNU. Under aerobic conditions, DDT was dehydrochlorinated to DDE and DBP. Aerobic degradation of DDT was diminished or inhibited in zones of high concentration, and increased significantly in zones of lower concentration: Other chlorinated pesticides identified in sediment included dieldrin and chlordane isomers. Multivariate analysis of the distributions of the DDTs suggested that there are probably two sources of DDD. In addition, DDE and DDMU are probably formed by similar mechanisms, i.e. dehydrochlorination. A steep concentration gradient existed from the Canal to the Outer Richmond Harbor, but higher levels of DDD than those found in the remainder of the Bay indicated that these contaminants are transported on particulates and colloidal organic matter from this source into San Francisco Bay. Chlorinated pesticides and PAHs may pose a potential problem to biota in San Francisco Bay.

  17. Trace analysis of trimethoprim and sulfonamide, macrolide, quinolone, and tetracycline antibiotics in chlorinated drinking water using liquid chromatography electrospray tandem mass spectrometry

    Science.gov (United States)

    Ye, Z.; Weinberg, H.S.; Meyer, M.T.

    2007-01-01

    A multirun analytical method has been developed and validated for trace determination of 24 antibiotics including 7 sulfonamides, 3 macrolides, 7 quinolones, 6 tetracyclines, and trimethoprim in chlorine-disinfected drinking water using a single solid-phase extraction method coupled to liquid chromatography with positive electrospray tandem mass spectrometry detection. The analytes were extracted by a hydrophilic-lipophilic balanced resin and eluted with acidified methanol (0.1% formic acid), resulting in analyte recoveries generally above 90%. The limits of quantitation were mostly below 10 ng/L in drinking water. Since the concentrated sample matrix typically caused ion suppression during electrospray ionization, the method of standard addition was used for quantitation. Chlorine residuals in drinking water can react with some antibiotics, but ascorbic acid was found to be an effective chlorine quenching agent without affecting the analysis and stability of the antibiotics in water. A preliminary occurrence study using this method revealed the presence of some antibiotics in drinking waters, including sulfamethoxazole (3.0-3.4 ng/L), macrolides (1.4-4.9 ng/L), and quinolones (1.2-4.0 ng/L). ?? 2007 American Chemical Society.

  18. 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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-15

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    M. Walker

    2010-06-01

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

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

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

    Directory of Open Access Journals (Sweden)

    M. Walker

    2011-01-01

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

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

  4. Reduction chlorination of slag containing niobium, tantalum and titanium

    International Nuclear Information System (INIS)

    Reduction chlorination experiments were carried out with slag containing niobium, tantalum in order to evaluate the effects of some variables on the behaviour of the material. Kinetic curves were obtained with the main variables being temperature and percentage of reducing agent. The results showed a greater effect of temperature as well as indicated the formation of the non-volatile chlorides (CaCl2) as a factor reducing the reaction rate. Quantitative analyses of the material collected in the condenser indicated the viability of the method to recover the valuable metals. (Author)

  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. Phytoscreening of BTEX and chlorinated solvents by tree coring

    DEFF Research Database (Denmark)

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

    chlorinated solvents. The method was applied at various European sites contaminated with PCE/TCE or BTEXs due to former site activities (industrial production, gas stations, air base or gas plant). Tree core samples were collected in fall 2013 and analyzed by HS-GC/MS. Results were used to map the plume...... level in the subsurface and plumes may be mapped. Various plants can be used for phytoscreening, however trees are preferable to smaller plants as their large root system can absorb chemicals from a broader and deeper area. Approach/Activities. In this study tree coring is tested for fuel components and...

  7. Two new chlorinated amides from Nicotiana glauca R. Graham.

    Science.gov (United States)

    Backheet, E Y; Sayed, H M

    2002-03-01

    Two new chlorinated amides, N-(2',6'-diethyl phenyl)-2-chloroacetamide (1) and N-(butyloxymethyl)-N-(2',6'-diethyl phenyl)-2-chloroacetamide (2) were isolated for the first time from the ethanolic extract of the leaves of Nicotiana glauca R. Graham in addition to triacontanol (3), scopoletin (4) and stigmasterol-3-beta-O-D-gluco-pyranoside (5). The structures of the isolated compounds were elucidated by spectroscopic analysis (1D, 2D NMR, EIMS, HR-EIMS, IR and UV). PMID:11933854

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

    OpenAIRE

    Hey, G.; Grabic, R.; Ledin, A.; la Cour Jansen, J; Andersen, H R

    2012-01-01

    Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0–20mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended nitrogen removal (low COD) and one without (high COD). About one third of the tested APIs resisted degradation even at the highest ClO2 dose (20mg/L), while others were reduced by more than 90% at the l...

  9. Future chlorine-bromine loading and ozone depletion

    Science.gov (United States)

    Prather, Michael J.; Ibrahim, Abdel Moneim; Sasaki, Toru; Stordal, Frode; Visconti, Guido

    1991-01-01

    The prediction of future ozone requires three elements: (1) a scenario for the net emissions of chemically and radiatively active trace gases from the land and oceans; (2) a global atmospheric model that projects the accumulation of these gases; and (3) a chemical transport model that describes the distribution of ozone for a prescribed atmospheric composition and climate. This chapter, of necessity, presents models for all three elements and focuses on the following: (1) atmospheric abundance of chlorine and bromine in the form of halocarbons; and (2) the associated perturbations to stratospheric ozone.

  10. Biodegradation of chlorinated solvents in a water unsaturated topsoil

    DEFF Research Database (Denmark)

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

    2003-01-01

    In order to investigate topsoils as potential sinks for chlorinated solvents from the atmosphere, the degradation of trichloromethane (CHCl3), 1,1,1-trichloroethane (CH3CCl3), tetrachloromethane (CCl4), trichloroethene (C2HCl3) and tetrachloroethene (C2Cl4) was studied in anoxic laboratory...... after 16 days. Based on the results in this study, we conclude that anaerobic topsoils are potential sinks for these contaminants, and that a natural attenuation potential exists, even in water unsaturated topsoils. (C) 2003 Elsevier Science Ltd. All rights reserved....

  11. Effect of chlorine in clay-mineral specimens prepared on silver metal-membrane mounts for X-ray powder diffraction analysis

    Science.gov (United States)

    Poppe, L.J.; Commeau, J.A.; Pense, G.M.

    1989-01-01

    Silver metal-membrane filters are commonly used as substrates in the preparation of oriented clay-mineral specimens for X-ray powder diffraction (XRD). The silver metal-membrane filters, however, present some problems after heat treatment if either the filters or the samples contain significant amounts of chlorine. At elevated temperature, the chloride ions react with the silver substrate to form crystalline compounds. These compounds change the mass-absorption coefficient of the sample, reducing peak intensities and areas and, therefore, complicating the semiquantitative estimation of clay minerals. A simple procedure that eliminates most of the chloride from a sample and the silver metal-membrane substrate is presented here.

  12. Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

    OpenAIRE

    Cameron B. Faxon; Bean, Jeffrey K.; Lea Hildebrandt Ruiz

    2015-01-01

    Measurements of molecular chlorine (Cl2), nitryl chloride (ClNO2), and dinitrogen pentoxide (N2O5) were taken as part of the DISCOVER-AQ Texas 2013 campaign with a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) using iodide (I-) as a reagent ion. ClNO2 concentrations exceeding 50 ppt were regularly detected with peak concentrations typically occurring between 7:00 a.m. and 10:00 am. Hourly averaged Cl2 concentrations peaked daily between 3:00 p.m. and 4:00...

  13. Inland Concentrations of Cl2 and ClNO2 in Southeast Texas Suggest Chlorine Chemistry Significantly Contributes to Atmospheric Reactivity

    OpenAIRE

    Faxon, Cameron; Bean, Jeffrey; Ruiz, Lea

    2015-01-01

    Measurements of molecular chlorine (Cl2), nitryl chloride (ClNO2), and dinitrogen pentoxide (N2O5) were taken as part of the DISCOVER-AQ Texas 2013 campaign with a High Resolution Time-of-Flight Chemical Ionization Mass Spectrometer (HR-ToF-CIMS) using iodide (I-) as a reagent ion. ClNO2 concentrations exceeding 50 ppt were regularly detected with peak concentrations typically occurring between 7:00 a.m. and 10:00 am. Hourly averaged Cl2 concentrations peaked daily between 3:00 p.m. and 4:00 ...

  14. Determination of chlorinated acid herbicides in vegetation and soil by liquid chromatography/electrospray-tandem mass spectrometry.

    Science.gov (United States)

    Schaner, Angela; Konecny, Jaclyn; Luckey, Laura; Hickes, Heidi

    2007-01-01

    The method presented uses reversed-phase liquid chromatography with negative electrospray ionization and tandem mass spectrometry to analyze 9 chlorinated acid herbicides in soil and vegetation matrixes: clopyralid, dicamba, MCPP, MCPA, 2,4-DP, 2,4-D, triclopyr, 2,4-DB, and picloram. A 20 g portion is extracted with a basic solution and an aliquot acidified and micropartitioned with 3 mL chloroform. Vegetation samples are subjected to an additional cleanup with a mixed-mode anion exchange solid-phase extraction cartridge. Two precursor product ion transitions per analyte are measured and evaluated to provide the maximum degree of confidence in results. Average recoveries for 3 different soil types tested ranged from 72 to 107% for all compounds with the exception of 2,4-DB at 56-99%. Average recoveries for the 3 different vegetation types studied were lower and ranged from 53 to 80% for all compounds. PMID:17955986

  15. Leaching of copper concentrates with high arsenic content in chlorine-chloride media

    International Nuclear Information System (INIS)

    This work reports the results of copper concentrates leaching which have high arsenic concepts (up to 2.5%). The treatments were carried out using chlorine that forms from sodium hypochlorite and sulphuric acid. The aim of this work is to obtain a solution having high copper content 4 to 6 g/l and 5 to 7 g/l free acid in order to submit it directly to a solvent extraction stage. In addition, this solution should have minimum content of arsenic and chloride ions. To carry out this investigation, an acrylic reactor was constructed where the leaching tests were made at constant temperature in a thermostatic bath under atmospheric pressure. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Typical variables were studied, such as leaching agent concentration, leaching time, pulp density and temperature among others. Some of the residues were analyzed by XRD and EPS. On the other hand, the solutions were analyzed by Atomic Absorption Spectroscopy. The results indicate solutions having the contents stated above can be obtained. (Author) 19 refs

  16. The effects of stainless steel finish on Salmonella Typhimurium attachment, biofilm formation and sensitivity to chlorine.

    Science.gov (United States)

    Schlisselberg, Dov B; Yaron, Sima

    2013-08-01

    Bacterial colonization and biofilm formation on stainless steel (SS) surfaces can be sources for cross contamination in food processing facilities, possessing a great threat to public health and food quality. Here the aim was to demonstrate the influence of surface finish of AISI 316 SS on colonization, biofilm formation and susceptibility of Salmonella Typhimurium to disinfection. Initial attachment of S. Typhimurium on surfaces of SS was four times lower, when surface was polished by Bright-Alum (BA) or Electropolishing (EP), as compared to Mechanical Sanded (MS) or the untreated surface (NT). The correlation between roughness and initial bacterial attachment couldn't account on its own to explain differences seen. Biofilms with similar thickness (15-18 μm) were developed on all surfaces 1-day post inoculation, whereas EP was the least covered surface (23%). Following 5-days, biofilm thickness was lowest on EP and MS (30 μm) and highest on NT (62 μm) surfaces. An analysis of surface composition suggested a link between surface chemistry and biofilm development, where the higher concentrations of metal ions in EP and MS surfaces correlated with limited biofilm formation. Interestingly, disinfection of biofilms with chlorine was up to 130 times more effective on the EP surface (0.005% surviving) than on the other surfaces. Overall these results suggest that surface finish should be considered carefully in a food processing plant. PMID:23628616

  17. Chapter 3. Chloric decomposition of aluminosilicate ores. 3.1. Features of chlorination of aluminium containing ores

    International Nuclear Information System (INIS)

    The features of chlorination of aluminium containing ores are considered in this article. Theoretical aspects of metals, oxides and natural compounds chlorination, specific features of synthesis of various chlorides are considered as well.

  18. The formation and fate of chlorinated organic substances in temperate and boreal forest soils

    Czech Academy of Sciences Publication Activity Database

    Clarke, N.; Fuksová, Květoslava; Gryndler, Milan; Lachmanová, Z.; Liste, H. H.; Rohlenová, Jana; Schroll, R.; Schröder, P.; Matucha, Miroslav

    2009-01-01

    Roč. 16, č. 2 (2009), s. 127-143. ISSN 0944-1344 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50200510 Keywords : Carbon cycle * Chlorination * Chlorine biogeochemistry Subject RIV: GK - Forestry Impact factor: 2.411, year: 2009

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

    Directory of Open Access Journals (Sweden)

    Daniel Serrano Sánchez

    2016-01-01

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

  20. Plant physiological response of strawberry fruit to chlorine dioxide gas treatment during postharvest storage

    Science.gov (United States)

    Chlorine dioxide, a strong oxidizing and sanitizing agent, is used as a postharvest sanitizer for fruits and vegetables and generally applied on a packing line using a chlorine dioxide generator. The objective of this research was to study the physiological responses of strawberries to ClO2 when app...

  1. Application of Chlorine Dioxide to Lessen Bacterial Contamination during Broiler Defeathering

    Science.gov (United States)

    Due to escape of contaminated gut contents, the number of Campylobacter spp. recovered from broiler carcasses increases during feather removal. Chlorine dioxide (ClO2) is approved for use as an antimicrobial treatment during poultry processing. A chlorine dioxide generator was placed in a commerci...

  2. 49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Chloric acid solution or chlorine dioxide hydrate, frozen. 173.229 Section 173.229 Transportation Other Regulations Relating to Transportation PIPELINE AND... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When...

  3. Chlorination and dechlorination rates in a forest soil - A combined modelling and experimental approach.

    Science.gov (United States)

    Montelius, Malin; Svensson, Teresia; Lourino-Cabana, Beatriz; Thiry, Yves; Bastviken, David

    2016-06-01

    Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Clorg). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Clorg are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Cl(-) transformed to Clorg per time unit) and specific dechlorination (i.e., fraction of Clorg transformed to Cl(-) per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 d(-1) and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01-0.03d(-1) and were similar among all treatments. This study finds that soil Clorg levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Clorg compounds, while another Clorg pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils. PMID:26950634

  4. IN-SITU AQUIFER RESTORATION OF CHLORINATED ALIPHATICS BY METHANOTROPHIC BACTERIA

    Science.gov (United States)

    This project evaluated the potential of enhanced in-situ biotransformation of chlorinated aliphatic solvents by a bacterial community grown on methane under aerobic conditions. The target chlorinated compounds were trichloroethene (TCE), cis-and trans-1,2-dichloroethene (DCE), an...

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

    Science.gov (United States)

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

    2012-01-01

    Inactivation experiments of seven strains of chlorine-resistant bacteria, isolated from a drinking water distribution system, were conducted with four kinds of disinfectants. All the bacteria showed high resistance to chlorine, especially for Mycobacterium mucogenicum. The CT value of 99.9% inactivation for M. mucogenicum, Sphingomonas sanguinis and Methylobacterium were 120 mg x (L x min)(-1), 7 mg x (L x min)(-1) and 4 mg x (L x min)(-1), respectively. The results of inactivation experiments showed that chlorine dioxide and potassium monopersulfate could inactive 5 lg of M. mucogenicum within 30 min, which showed significantly higher efficiency than free chlorine and monochloramine. Free chlorine was less effective because the disinfectant decayed very quickly. Chloramination needed higher concentration to meet the disinfection requirements. The verified dosage of disinfectants, which could effectively inactivate 99.9% of the highly chlorine-resistant M. mucogenicum within 1 h, were 3.0 mg/L monochloramine, 1.0 mg/L chlorine dioxide (as Cl2), and 1.0 mg/L potassium monopersulfate (as Cl2). It was suggested that the water treatment plants increase the concentration of monochloramine or apply chlorine dioxide intermittently to control the disinfectant-resistant bacteria. PMID:22452196

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

    Science.gov (United States)

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

    2014-05-01

    Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. PMID:24534637

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    This study describes the possible separation of chlorinated plastic films (PVC and PVDC) from other heavy plastic packaging waste (PPW) by selective twist formation and gravity separation. Twists formation was mechanically induced in chlorinated plastic films, whereas twist formation did not occur in PS and PET films. After twist formation, all the films had the apparent density of less than 1.0 g/cm3 and floated in water even though the true density was more than 1.0 g/cm3. However, the apparent density of the PS and the PET films increased with agitation to more than 1.0 g/cm3, whereas that of chlorinated plastic films was kept less than 1.0 g/cm3. The main reason would be the air being held inside the chlorinated plastic films which was difficult to be removed by agitation. Simple gravity separation after twist formation was applied for artificial film with 10 wt.% of the chlorinated films and real PPW films with 9 wt.% of the chlorinated films. About 76 wt.% of the artificial PPW films and 75 wt.% of real PPW films after the removal of PP and PE were recovered as settling fraction with 4.7 wt.% and 3.0 wt.% of chlorinated plastic films, respectively. These results indicate that simple gravity separation process after twist formation can be used to reduce the chlorinated plastic concentration from mixed heavy PPW films.

  10. POPULATION DIVERSITY IN MODEL DRINKING WATER BIOFILMS RECEIVING CHLORINE OR MONOCHLORAMINE RESIDUAL

    Science.gov (United States)

    Most water utilities add monochloramine or chlorine as a residual disinfectant in potable water distribution systems (WDS) to control bacterial regrowth. While monochloramine is considered more stable than chlorine, little is known about the fate of this disinfectant or the effec...

  11. Inactivation of Spores of Bacillus anthracis Sterne, Bacillus cereus, and Bacillus thuringiensis subsp. israelensis by Chlorination

    OpenAIRE

    Rice, E W; Adcock, N. J.; Sivaganesan, M; Rose, L. J.

    2005-01-01

    Three species of Bacillus were evaluated as potential surrogates for Bacillus anthracis for determining the sporicidal activity of chlorination as commonly used in drinking water treatment. Spores of Bacillus thuringiensis subsp. israelensis were found to be an appropriate surrogate for spores of B. anthracis for use in chlorine inactivation studies.

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

    Science.gov (United States)

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

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

    NARCIS (Netherlands)

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

    2015-01-01

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

  14. Sodium and chlorine concentrations in mixed saliva of healthy and cystic fibrosis children

    International Nuclear Information System (INIS)

    Sodium and chlorine concentrations in mixed saliva were simultaneously measured by neutron activation analysis in nine normal children and in nine patients with cystic fibrosis. Sodium levels showed a significant difference (P < 0.01) between patients and controls. The concentration of chlorine was similar in both the control and the cystic fibrosis groups. (author)

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Leo H. H. [School of Biomedical Engineering, McMaster University, Hamilton L8S 4L8 (Canada); Hoque, Enamul; Kruse, Peter [Department of Chemistry and Chemical Biology, McMaster University, Hamilton L8S 4L8 (Canada); Ravi Selvaganapathy, P. [School of Biomedical Engineering, McMaster University, Hamilton L8S 4L8 (Canada); Department of Mechanical Engineering, McMaster University, Hamilton L8S 4L7 (Canada)

    2015-02-09

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

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

  19. 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

  20. 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

    pyrite oxidation as confirmed by the depleted sulfur isotope signature of SO4 2−. In the same zone, PCE and trichloroethene (TCE) disappeared and cis- 1,2-dichloroethene (cDCE) became the dominant chlorinated ethene. PCE and TCE were likely transformed by reductive dechlorination rather than abiotic...... reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of 13C in the daughter products followed by an enrichment of 13C as degradation proceeded. At 1000 m downgradient...

  1. 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

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

    DEFF Research Database (Denmark)

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

    2012-01-01

    nitrogen removal (low COD) and one without (high COD). About one third of the tested APIs resisted degradation even at the highest ClO2 dose (20mg/L), while others were reduced by more than 90% at the lowest ClO2 level (0.5mg/L). In the low COD effluent, more than half of the APIs were oxidized at 5mg/L Cl......Biologically treated wastewater spiked with a mixture of 56 active pharmaceutical ingredients (APIs) was treated with 0–20mg/L chlorine dioxide (ClO2) solution in laboratory-scale experiments. Wastewater effluents were collected from two wastewater treatment plants in Sweden, one with extended......O2, while in high COD effluent a significant increase in API oxidation was observed after treatment with 8mg/L ClO2. This study illustrates the successful degradation of several APIs during treatment of wastewater effluents with chlorine dioxide....

  3. Chlorine/chloride based processes for uranium ores

    International Nuclear Information System (INIS)

    The CE Lummus Minerals Division was commissioned by The Department of Supply and Services to develop order-of-magnitude capital and operating cost estimates for chlorine/chloride-based processes for uranium ores. The processes are designed to remove substantially all radioactive consituents from the ores to render the waste products harmless. Two processes were selected, one for a typical low grade ore (2 lb. U3O8/ton ore) and one for a high grade ore (50 lbs U3O8 /ton). For the low grade ore a hydrochloric acid leaching process was chosen. For high grade ore, a more complex process, including gaseous chlorination, was selected. Capital cost estimates were compiled from information obtained from vendors for the specified equipment. Building cost estimates and the piping, electrical and instrumentation costs were developed from the plant layout. Utility diagrams and mass balances were used for estimating utilities and consumables. Detailed descriptions of the bases for capital and operating cost estimates are given

  4. 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.

  5. Chlorine-36 dating of old groundwater. Chapter 6

    International Nuclear Information System (INIS)

    Chlorine-36 has been widely used for dating old groundwater. The 36Cl used for this purpose is produced in the atmosphere through the interaction of cosmic rays with argon atoms. The 36Cl then mixes with ordinary atmospheric chloride (mostly derived from the ocean). The mixture is deposited on the land surface dissolved in rain or snow or as dry aerosols. Groundwater recharge carries the 36Cl into the subsurface where the radiometric ‘clock’ is set. Chloride is conservative in the subsurface and, thus, the 36Cl is rarely retarded with respect to the water velocity by adsorption or geochemical reactions. Groundwater age can be estimated using the radiometric decay equation and the decrease in 36Cl from the amount in the recharge water. The main complication is variations in the Cl concentration of groundwater. This can potentially be due to variable evapotranspiration during recharge or to the addition of Cl in the aquifer. If the cause of Cl concentration variations is understood, the age calculation can be corrected to account for the process. Chlorine-36 dating is generally applicable to water in the age range 100 ka–1 Ma.

  6. Ash characteristics in controlled diode laser pyrolysis of chlorinated rubber

    Science.gov (United States)

    Peligrad, A. A.; Schmidt, M. J. J.; Li, L.; Spencer, J. T.

    2000-02-01

    This paper describes the effects of 60 W High Power Diode Laser (HPDL) beams on the removal of chlorinated rubber (CR) paint from concrete surfaces and the ash particles generated from this process. The physical characteristics, including shape and size distribution of the removed and collected airborne CR particles, down to a size of around 1 μm in diameter, were determined using optical microscopy and image analysis. The shape of the particles observed was highly irregular, displaying no symmetry. The size distribution of the collected particles was found to range between 1-2000 μm, with the maximum concentration being found between 29 and 60 μm. The chemical characteristics of the CR ash particles were investigated by means of ESEM and EDX techniques. From a comparative analysis, it was found that the concentration of chlorine within the CR material was significantly reduced after HPDL treatment. This, together with DTA/TGA results indicated a combustive degradation of the CR polymer through the interaction with the process gas, oxygen, and the laser irradiation. Also, a strong correlation between laser power and average particle sizes has been found, with higher powers generally producing larger particle sizes. Opposite effects have been found by changing the oxygen flow rate, with higher oxygen flow producing, on average, smaller particles. An interpretation of the combustion process, as well as a brief discussion on operational safety and environmental impact of the products is attempted.

  7. Evidence for heterogeneous chlorine activation in the tropical UTLS

    Directory of Open Access Journals (Sweden)

    M. von Hobe

    2010-07-01

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

  8. Ultrasonic aqueous cleaning as a replacement for chlorinated solvent cleaning

    International Nuclear Information System (INIS)

    The Oak Ridge Y-12 Plant has been involved in the replacement of chlorinated solvents since 1982. One of the most successful replacement efforts has been the substitution of vapor degreasers or soak tanks using chlorinated solvents with ultrasonic cleaning using aqueous detergents. Recently, funding was obtained from the Department of Energy Office (DOE) of Technology Development to demonstrate this technology. A unit has been procured and installed in the vacuum pump shop area to replace the use of a solvent soak tank. Initially, the solvents used in the shop were CFC-113 and a commercial brand cleaner which contained both perchloroethylene and methylene chloride. While the ultrasonic unit was being procured, a terpene-based solvent was used. Generally, parts were soaked overnight in order to soften baked-on vanish. Many times, wire brushing was used to help remove remaining contamination. Initial testing with the ultrasonic cleaner indicated cleaning times of 20 min were as effective as the overnight solvent soaks in removing contamination. Wire brushing was also not required following the ultrasonic cleaning as was sometimes required with the solvent soak

  9. Field-usable portable analyzer for chlorinated organic compounds

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-10-01

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

  10. Evidence for heterogeneous chlorine activation in the tropical UTLS

    Directory of Open Access Journals (Sweden)

    M. von Hobe

    2011-01-01

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

  11. Tritium and chlorine-36 migration from a nuclear explosion cavity

    International Nuclear Information System (INIS)

    The Radionuclide Migration (RNM) Experiment consists of a 600 gpm pumping well placed approximately 90 m away from the center of the rubble chimney and cavity created by the 1965 Cambric event. The purpose of the experiment is to deliberately draw radionuclides away from the cavity and produce breakthrough curves of the migrating radionuclides at the pumping well. Tritium and chlorine-36 are the most mobile radionuclides and they have produced breakthrough curves that are very amenable to analysis. The other radionuclides that have been observed at the pumping well are ruthenium-106, Kr-85 and I-129, in very small quantities. A conceptual model of the Cambric cavity and surrounding hydrogeologic environment was formulated using available field data such as core samples and the breakthrough curves of tritium and chlorine-36. Results show that the cavity hydraulic conductivity is about one-tenth as large as the average hydraulic conductivity of the surrounding medium. The calibrated model required the addition of retardation of the tritium. The breakthrough curve was relatively insensitive to variations in the other parameters tested in the sensitivity study

  12. Generation of chlorine by-products in simulated wash water.

    Science.gov (United States)

    Shen, Cangliang; Norris, Pauline; Williams, Olivia; Hagan, Stephanie; Li, KaWang

    2016-01-01

    Free chlorine (FC) reacting with organic matter in wash water promotes the formation of chlorine by-products. This study aims to evaluate the dynamic impact of FC and organic load on the generation of haloacetic acids (HAAs) and trihalomethanes (THMs) in simulated wash water. Lettuce juice was sequentially added into FC solution with FC periodically replenished. Water samples were collected after each lettuce juice addition to measure water qualities and determine HAAs and THMs using US-Environmental-Protection-Agency (EPA) methods. Concentrations of 88-2103 μg/l of total HAAs and 20.79-859.47 μg/l of total THMs were detected during the study. Monobromoacetic, tribromoacetic, chlorodibromoacetic and trichloroacetic acid were the major HAAs components. Chloroform (trichloromethane) was the primary THMs present. A significant correlation of HAAs with chemical oxygen demand and THMs with FC was observed. Results indicated that optimizing wash water sanitizing systems to limit organic matters and maintain minimal effective FC concentration is critical. PMID:26212946

  13. 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.

  14. On the chemical nature of boundary lubrication of stainless steel by chlorine - and sulfur-containing EP-additives

    DEFF Research Database (Denmark)

    Petrushina, Irina; Christensen, Erik; Bergqvist, Rene Stig; Møller, Poul Bildsøe; Bjerrum, Niels; Høj, Jakob Weiland; Kann, G.; Chorkendorff, Ib

    paraffin was equally active with iron, chromium and nickel. The better lubrication performance demonstrated by chlorinated paraffin compared to dialkylpolysulfides was attributed to the chemical activity of the chlorinated paraffin with all the main components of stainless steel. The depth profiles of the...... the Me-powder (where Me = iron, chromium or nickel)-dialkylpolysulfide (or chlorinated paraffin) mixtures have shown that dialkylpolysulfide was chemically active with iron and nickel (the highest activity was with nickel). Chromium was practically nonactive with dialkylpolysulfide. Chlorinated...

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

    International Nuclear Information System (INIS)

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

  16. 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

  17. 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)

  18. 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)

  19. 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)

  20. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-01

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

  2. Inhibition of chlorine-induced pulmonary inflammation and edema by mometasone and budesonide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jing; Mo, Yiqun; Schlueter, Connie F.; Hoyle, Gary W., E-mail: Gary.Hoyle@louisville.edu

    2013-10-15

    Chlorine gas is a widely used industrial compound that is highly toxic by inhalation and is considered a chemical threat agent. Inhalation of high levels of chlorine results in acute lung injury characterized by pneumonitis, pulmonary edema, and decrements in lung function. Because inflammatory processes can promote damage in the injured lung, anti-inflammatory therapy may be of potential benefit for treating chemical-induced acute lung injury. We previously developed a chlorine inhalation model in which mice develop epithelial injury, neutrophilic inflammation, pulmonary edema, and impaired pulmonary function. This model was used to evaluate nine corticosteroids for the ability to inhibit chlorine-induced neutrophilic inflammation. Two of the most potent corticosteroids in this assay, mometasone and budesonide, were investigated further. Mometasone or budesonide administered intraperitoneally 1 h after chlorine inhalation caused a dose-dependent inhibition of neutrophil influx in lung tissue sections and in the number of neutrophils in lung lavage fluid. Budesonide, but not mometasone, reduced the levels of the neutrophil attractant CXCL1 in lavage fluid 6 h after exposure. Mometasone or budesonide also significantly inhibited pulmonary edema assessed 1 day after chlorine exposure. Chlorine inhalation resulted in airway hyperreactivity to inhaled methacholine, but neither mometasone nor budesonide significantly affected this parameter. The results suggest that mometasone and budesonide may represent potential treatments for chemical-induced lung injury. - Highlights: • Chlorine causes lung injury when inhaled and is considered a chemical threat agent. • Corticosteroids may inhibit lung injury through their anti-inflammatory actions. • Corticosteroids inhibited chlorine-induced pneumonitis and pulmonary edema. • Mometasone and budesonide are potential rescue treatments for chlorine lung injury.

  3. Effects of assimilable organic carbon and free chlorine on bacterial growth in drinking water.

    Directory of Open Access Journals (Sweden)

    Xiaolu Liu

    Full Text Available Assimilable organic carbon (AOC is one of the most important factors affecting the re-growth of microorganisms in drinking water. High AOC concentrations result in biological instability, but disinfection kills microbes to ensure the safety of drinking water. Free chlorine is an important oxidizing agent used during the disinfection process. Therefore, we explored the combined effects of AOC and free chlorine on bacterial growth in drinking water using flow cytometry (FCM. The initial AOC concentration was 168 μg.L(-1 in all water samples. Without free chlorine, the concentrations of intact bacteria increased but the level of AOC decreased. The addition of sodium hypochlorite caused an increase and fluctuation in AOC due to the oxidation of organic carbon. The concentrations of intact bacteria decreased from 1.1 × 10(5 cells.mL(-1 to 2.6 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.6 mg.L(-1 to 4.8 × 10(4 cells.mL(-1 at an initial free chlorine dose of 0.3 mg.L(-1 due to free chlorine originating from sodium hypochlorite. Additionally, free chlorine might be more obviously affected AOC concentrations than microbial growth did. These results suggested that AOC and free chlorine might have combined effects on microbial growth. In this study, our results showed concentrations determined by FCM were higher than those by HPC, which indicated that some E. coli detected by FCM might not be detected using HPC in drinking water. The level of free chlorine might restrain the consumption of AOC by inhibiting the growth of E. coli; on the other hand, chlorination might increase the level of AOC, thereby increase the potential for microbial growth in the drinking water network.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Vacchi, Francine Inforcato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil); Ormond, Alexandra B.; Freeman, Harold S. [Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Zocolo, Guilherme Juliao; Zanoni, Maria Valnice Boldrin [Departamento de Quimica Analitica, Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Quimica de Araraquara, Araraquara, SP 14801-970 (Brazil); Umbuzeiro, Gisela, E-mail: giselau@ft.unicamp.br [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil)

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: Black-Right-Pointing-Pointer Aqueous solutions of Disperse Red 1 were treated with chlorine. Black-Right-Pointing-Pointer The chlorination products of Disperse Red 1 were identified using LC-ESI-MS/MS. Black-Right-Pointing-Pointer Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. Black-Right-Pointing-Pointer The chlorinated dye was more mutagenic

  6. 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

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

    International Nuclear Information System (INIS)

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC–ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: ► Aqueous solutions of Disperse Red 1 were treated with chlorine. ► The chlorination products of Disperse Red 1 were identified using LC–ESI-MS/MS. ► Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. ► The chlorinated dye was more mutagenic than the dye itself. ► Chlorination should be avoided in effluents containing azo-dyes.

  8. 40 CFR 141.535 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Science.gov (United States)

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.535 Section 141.535 Protection of Environment... § 141.535 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must...

  9. 40 CFR 141.544 - What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection?

    Science.gov (United States)

    2010-07-01

    ..., ozone, or chlorine dioxide for primary disinfection? 141.544 Section 141.544 Protection of Environment... Benchmark § 141.544 What if my system uses chloramines, ozone, or chlorine dioxide for primary disinfection? If your system uses chloramines, ozone or chlorine dioxide for primary disinfection your system...

  10. Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: effects on its optical and antioxidant properties.

    Science.gov (United States)

    Wenk, Jannis; Aeschbacher, Michael; Salhi, Elisabeth; Canonica, Silvio; von Gunten, Urs; Sander, Michael

    2013-10-01

    In water treatment dissolved organic matter (DOM) is typically the major sink for chemical oxidants. The resulting changes in DOM, such as its optical properties have been measured to follow the oxidation processes. However, such measurements contain only limited information on the changes in the oxidation states of and the reactive moieties in the DOM. In this study, we used mediated electrochemical oxidation to quantify changes in the electron donating capacities (EDCs), and hence the redox states, of three different types of DOM during oxidation with chlorine dioxide (ClO2), chlorine (as HOCl/OCl(-)), and ozone (O3). Treatment with ClO2 and HOCl resulted in comparable and prominent decreases in EDCs, while the UV light absorbances of the DOM decreased only slightly. Conversely, ozonation resulted in only small decreases of the EDCs but pronounced absorbance losses of the DOM. These results suggest that ClO2 and HOCl primarily reacted as oxidants by accepting electrons from electron-rich phenolic and hydroquinone moieties in the DOM, while O3 reacted via electrophilic addition to aromatic moieties, followed by ring cleavage. This study highlights the potential of combined EDC-UV measurements to monitor chemical oxidation of DOM, to assess the nature of the reactive moieties and to study the underlying reaction pathways. PMID:23978074

  11. Lethal and sublethal effects of chlorine, phenol, and chlorine-phenol mixtures on the mud crab, Panopeus herbstii

    International Nuclear Information System (INIS)

    The mud crab, Panopeus herbstii, was acutely exposed (96-hr) to chlorine-produced oxidants (CPO), phenol, and a CPO-phenolic mixture (1:1) to determine lethal and sublethal effects. The 96-hr (LC50) values were determined for each individual compound and mixture. Additionally, whole-animal respiration rates were measured following acute exposure to sublethal concentrations of each compound or mixture. Phenol uptake/depuration rates were measured in the phenol and CPO-phenol mixture concentrations. Results indicated 96-hr LC50 values of 1.06 mg/L for CPO, 52.8 mg/L for phenol, and 184.7 mg/L total toxicant units (TTU) for the CPO-phenol mixture. Statistical analysis indicated that the acute toxicity of the CPO-phenol mixture was less than additive. Sublethal studies indicated that only acute exposure to sublethal concentrations of CPO caused altered respiration rates. After 96-hr depuration, metabolic rates in all CPO-exposure crabs generally returned to control rates. Uptake/depuration rate studies indicated significantly lower phenol uptake rates in crabs exposed to the CPO-phenol mixture. These findings suggest that the less-than-additive toxicity of the CPO-phenol mixture may result from lowered uptake/depuration rate kinetics and indicate that the discharge of chlorinated-phenolic waste may not result in additive and/or synergistic interactions, but rather in less-than-additive effect on decapod aquatic species

  12. Stratospheric ozone conservation by electron attachment to chlorine atoms: The negative-ion chemistry

    International Nuclear Information System (INIS)

    Creating low-energy electrons in the stratosphere by photoelectric emission has the beneficial effect of suppressing ozone destruction by Cl. This is because Cl is converted to Cl-, which is less reactive. Critical to the success of this scheme is the ability to attach most of the electrons to Cl- and its hydrates Cl- (H2O). We found that this attachment efficiency is rather high. This is remarkable given the fact that the electron affinity of Cl- is less than that of NO3-. Photoddetachment of NO3- is the key factor that leads to this high efficiency. Computer calculations show that ozone increases with electron injection, and most of the electrons end up attaching to Cl-(H2O). We also point out that 40 km, the altitude at which most of the ozone destruction occurs, is also the optimum altitude for injecting photoelectric electrons. 12 refs., 6 figs

  13. Prompt gamma ray evaluation for chlorine analysis in blended cement concrete

    International Nuclear Information System (INIS)

    Single prompt gamma ray energy has been evaluated to measure chlorine concentration in fly ash (FA), Super-Pozz (SPZ) and blast furnace slag (BFS) cement concrete specimens using a portable neutron generator-based Prompt Gamma Neutron Activation (PGNAA) setup. The gamma ray yield data from chloride concentration measurement in FA, SPZ and BFS cement concretes for 2.86–3.10, 5.72 and 6.11 MeV chlorine gamma rays were analyzed to identify a gamma ray with common slope (gamma ray yield/Cl conc. wt%) for the FA, BFS and SPZ cement concretes. The gamma ray yield data for FA and SPZ cement concretes with varying chloride concentration were measured previously using a portable neutron generator-based PGNAA setup. In the current study, new data have been measured for chlorine detection in the BFS cement concrete using a portable neutron generator-based PGNAA setup for 2.86–3.10, 5.72, and 6.11 MeV chlorine gamma rays. The minimum detection limit of chlorine in BFS cement concrete (MDC) was found to be 0.034±0.010, 0.032±0.010, 0.033±0.010 for 2.86–3.10, 5.72 and 6.11 MeV gamma ray, respectively. The new BFS cement concrete data, along with the previous measurements for FA and SPZ cement concretes, have been utilized to identify a gamma ray with a common slope to analyze the Cl concentration in all of these blended cement concretes. It has been observed that the 6.11 MeV chlorine gamma ray has a common slope of 5295±265 gamma rays/wt % Cl concentration for the portable neutron generator-based PGNAA setup. The minimum detectable concentration (MDC) of chlorine in blended cement concrete was measured to be 0.033±0.010 wt % for the portable neutron generator-based PGNAA. Thus, the 6.11 MeV chlorine gamma ray can be used for chlorine analysis of blended cement concretes. - Highlights: • New data on chlorine measurements in BFS cement concrete is presented. • Single chlorine gamma ray was evaluated for chlorine analysis in blended cement concrete. • 6.11 Me

  14. Influence of Plants on Chlorine Cycling in Terrestrial Environments

    Science.gov (United States)

    Montelius, Malin; Thiry, Yves; Marang, Laura; Ranger, Jacques; Cornelis, Jean-Thomas; Svensson, Teresia; Bastviken, David

    2016-04-01

    Chlorine (Cl), one of the 20 most abundant elements on Earth, is crucial for life as a regulator of cellular ionic strength and an essential co-factor in photosynthesis. Chlorinated organic compounds (Clorg) molecules are surprisingly abundant in soils, in fact many studies during the last decades show that Clorg typically account for more than 60% of the total soil Cl pool in boreal and temperate forest soils and frequently exceed chloride (Cl-) levels. The natural and primarily biotic formation of this Clorg pool has been confirmed experimentally but the detailed content of the Clorg pool and the reasons for its high abundance remains puzzling and there is a lack of Cl budgets for different ecosystems. Recently, the radioisotope 36Cl has caused concerns because of presence in radioactive waste, a long half-life (301 000 years), potential high mobility, and limited knowledge about Cl residence times, speciation and uptake by organisms in terrestrial environments. The chlorination of organic molecules may influence the pool of available Cl- to organisms and thereby the Cl cycling dynamics. This will prolong residence times of total Cl in the soil-vegetation system, which affects exposure times in radioactive 36Cl isotope risk assessments. We tested to what extent the dominating tree species influences the overall terrestrial Cl cycling and the balance between Cl- and Clorg. Total Cl and Clorg were measured in different tree compartments and soil horizons in the Breuil experimental forest, Bourgogne, established in 1976 and located at Breuil-Chenue in Eastern France. The results from this field experiment show how the dominating tree species affected Cl cycling and accumulation over a time period of 30 years. Cl uptake by trees as well as content of both total Cl and Clorg in soil humus was much higher in experimental plots with coniferous forests compared to deciduous forests. The amounts of Clorg found in plant tissue indicate significant Clorg production inside

  15. Electricity Storage and the Hydrogen-Chlorine Fuel Cell

    Science.gov (United States)

    Rugolo, Jason Steven

    Electricity storage is an essential component of the transforming energy marketplace. Its absence at any significant scale requires that electricity producers sit ready to respond to every flick of a switch, constantly adjusting power production to meet demand. The dispatchable electricity production technologies that currently enable this type of market are growing unpopular because of their carbon emissions. Popular methods to move away from fossil fuels are wind and solar power. These sources also happen to be the least dispatchable. Electricity storage can solve that problem. By overproducing during sunlight to store energy for evening use, or storing during windy periods for delivery in future calm ones, electricity storage has the potential to allow intermittent renewable sources to constitute a large portion of our electricity mix. I investigate the variability of wind in Chapter 2, and show that the variability is not significantly reduced by geographically distributing power production over the entire country of the Netherlands. In Chapter 3, I calculate the required characteristics of a linear-response, constant activity storage technology to map wind and solar production scenarios onto several different supply scenarios for a range of specified system efficiencies. I show that solid electrode batteries have two orders of magnitude too little energy per unit power to be well suited for renewable balancing and emphasize the value of the modular separation between the power and energy components of regenerative fuel cell technologies. In Chapter 4 I introduce the regenerative hydrogen-chlorine fuel cell (rHCFC), which is a specific technology that shows promise for the above applications. In collaboration with Sustainable Innovations, we have made and tested 6 different rHCFCs. In order to understand the relative importance of the different inefficiencies in the rHCFC, Chapter 5 introduces a complex temperature and concentration dependent model of the r

  16. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  17. Photocatalytic destruction of chlorinated solvents with solar energy

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, J.; Prairie, M.; Yellowhorse, L.

    1990-01-01

    Sandia National Laboratories and the Solar Energy Research Institute are developing a photocatalytic process to destroy organic contaminants in water. Tests with common water pollutants are being conducted at Sandia's Solar Thermal Test Facility using a near commercial-scale single-axis tracking parabolic trough system with glass pipe mounted at its focus. Experiments at this scale provide verification of laboratory studies and allow examination of design and operation issues at a real-life scale. The catalyst, titanium dioxide (TiO{sub 2}), is a harmless material found in paint, cosmetics and toothpaste. Experiments were conducted to determine the effect of key process parameters on destruction rates of two chlorinated organic compounds which are common water pollutants: trichloroethylene and trichloroethane. In this paper, we summarize the engineering-scale results of these experiments and analyses. 21 refs., 8 figs.

  18. Chlorinated solvent replacements recycle/recovery review report

    Energy Technology Data Exchange (ETDEWEB)

    Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. (Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering)

    1992-08-01

    This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

  19. Phytoremediation of chlorinated ethenes in seepline sediments: tree selection.

    Science.gov (United States)

    Stanhope, Andrine; Berry, Christopher J; Brigmon, Robin L

    2008-01-01

    Phytoremediation of chlorinated ethene (CE)-contaminated water was investigated at the Savannah River Site in Aiken, SC, USA. Perchloroethylene (PCE) and trichloroethylene (TCE) are present where CE-contaminated groundwater currently outcrops in seepline soils. Results of constructed and planted test cells, filled with soil from a noncontaminated seepline area and supplied with CE-contaminated groundwater (48 ppb) in the field for one season are presented. These test cells were planted with loblolly pines, hybrid poplars, coyote willow, and sweet gum. Cis-dichloroethylene (cDCE), a byproduct from rhizosphere microbial activity, was detected in the soils as well as some tree tissues. All trees tested were found to uptake both PCE and TCE (5-50 pbb/gm dry wt). PMID:19260231

  20. Molten salt destruction of rubber and chlorinated solvents

    International Nuclear Information System (INIS)

    Acceptable methods for the treatment of mixed wastes are not currently available. The authors have investigated Molten Salt Destruction (MSD) as an alternative to incineration of mixed wastes. MSD differs from incineration in several ways: there is no evidence of open flames in MSD, the containment of actinides is accomplished by chemical means (wetting and dissolution), the operating temperature of MSD is much lower (700--590 C vs 1,000--1,200 C) thus lowering the volatility of actinides. Furthermore, no acid gases are released from MSD. These advantages provide the main incentive for developing MSD as an alternative to incineration. The authors have demonstrated the viability of the MSD process to cleanly destroy rubber and chlorinated solvents

  1. Optimal intervention strategies for cholera outbreak by education and chlorination

    Science.gov (United States)

    Bakhtiar, Toni

    2016-01-01

    This paper discusses the control of infectious diseases in the framework of optimal control approach. A case study on cholera control was studied by considering two control strategies, namely education and chlorination. We distinct the former control into one regarding person-to-person behaviour and another one concerning person-to-environment conduct. Model are divided into two interacted populations: human population which follows an SIR model and pathogen population. Pontryagin maximum principle was applied in deriving a set of differential equations which consists of dynamical and adjoin systems as optimality conditions. Then, the fourth order Runge-Kutta method was exploited to numerically solve the equation system. An illustrative example was provided to assess the effectiveness of the control strategies toward a set of control scenarios.

  2. Challenges in subsurface in situ remediation of chlorinated solvents

    DEFF Research Database (Denmark)

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

    2014-01-01

    Chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality at many sites worldwide. In situ remediation of these sites is particularly challenging in heterogeneous fractured media and where the solvents are present as DNAPL. In situ remediation by chemical as...... dissolution of the DNAPL. Most recent research has been aimed at overcoming these challenges by enhanced and targeted reactant delivery methods. These include a wide range of very diverse technologies such as: enhanced injection methods, including fracturing; electrokinetic enhancement of delivery; ZVI...... very variable and rather unpredictable in heterogeneous geologic media, hence, further developments are needed. The novel techniques involving electrokinetics induce migration of primarily ionic species/reactants independent of hydraulic permeability differences, hence transporting the reactant into...

  3. Degradation of Chlorinated Aromatic Compounds in UASB Reactors

    DEFF Research Database (Denmark)

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

    1995-01-01

    Data on anaerobic degradation of chloroaromatic compounds in Upflow Anaerobic Sludge Blanket Reactors (UASB-reactor) are presented and compared. Special attention is given to the metabolic pathways for degradation of chlorinated phenols by granular sludge. Results indicate that PCP can be degraded...... in UASB-reactors via stepwise dechlorination to phenol. Phenol will subsequently be converted to benzoate before ring cleavage. Dechlorination proceeds via different pathways dependent upon the inocula used. Results are further presented on the design of special metabolic pathways in granules which do...... not possess this activity using the dechlorinating organism, Desulfomonile tiedjei. Additionally, it is shown that it is possible to immobilize Dechlorosporium hafniense, a newly isolated dechlorinating anaerobe, into granular sludge, thereby introducing an ability not previously present in the granules....

  4. Groundwater sustainability in Central Australia studied using chlorine-36

    International Nuclear Information System (INIS)

    The sustainability of Aboriginal community water supplies in arid Central Australia has been evaluated using the radioisotope chlorine-36 as a tracer within groundwaters to indicate the age of waters being tapped by local bores. Shallow regional groundwaters from fractured sandstones of the Ngalia Basin, fractured metamorphic rocks and Cainozoic sands and gravels show a bimodal distribution of 36Cl ratios. The higher ratio probably represents modern (Holocene) recharge diluted with windblown salts from local playa lakes and is seen in bores around the margin. The lower ratio corresponds to a 36Cl age of 80-100ka, implying that the last major recharge occurred during the last interglacial. These values are mainly observed in the interior of the basin, and are believed to be minimum ages for most of the shallow groundwaters in this region. Substantial recharge only appears to occur during favourable interglacial climatic regimes. Most community water supplies depend on these waters. (authors)

  5. Acid digestion of chlorine-containing wastes, (2)

    International Nuclear Information System (INIS)

    In the Plutonium Fuel Fabrication Facility, about 40% of the alpha-contaminated solid wastes contains organic chlorides, mainly PVC sheets and chloroprene rubber gloves. Acid digestion has been developed to reduce the volume of alpha-contaminated wastes, while converting the wastes into stable nonreactive residue. Based on the results of the basic studies on the acid digestion for nonradioactive chlorine-containing wastes, a non-radioactive pilot plant equipped with a 200 l digester was designed and constructed to confirm the performance in scaled-up process and the engineering problems. The following matters are described: the pilot plant of nonradioactive acid digestion and the experiments performed with it to confirm the reproducibility of the results of basic studies and to verify the safety of the processes. Many useful results were able to be obtained for the nitric acid oxidation processes. (J.P.N.)

  6. Full-scale study of removal effect on Cyclops of zooplankton with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    LIN Tao; CUI Fu-yi; LIU Dong-mei; AN Dong

    2004-01-01

    Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water etc. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

  7. Trihalomethane occurrence in chlorinated reclaimed water at full-scale wastewater treatment plants in NE Spain.

    Science.gov (United States)

    Matamoros, Víctor; Mujeriego, Rafael; Bayona, Josep M

    2007-08-01

    Total trihalomethane (TTHM) concentrations were determined in three chlorinated effluents (i.e. secondary and tertiary) from full-scale wastewater treatment plants (WWTP) in NE Spain over a 2-year monitoring period (May 2003-February 2005). Low TTHM concentrations (2-30 microg L(-1)), according to international standards for drinking water (80-150 microg L(-1)), were obtained in all samples analysed. The effects of (a) ammonia nitrogen and bromide concentrations, (b) UV light exposure, (c) tank storage, and (d) water temperature were evaluated. Two chlorination strategies were adopted: low chlorine dosages (2-5 mg Cl2 L(-1)) and a high-chlorine dosage (16 mg Cl2 L(-1)). The effects of storing chlorinated reclaimed water and of UV light exposure before chlorination were also evaluated. Samples collected over the 2-year monitoring period offered the possibility to assess the numerous variables affecting THM formation. A statistical evaluation of Platja d'Aro WWTP data set shows a low TTHM formation in the presence of high ammonia nitrogen concentration (pbromide (0-1 mg L(-1)) was also recorded (pwater reclamation plants monitored. Nevertheless, no statistical difference was observed when chlorinated effluents were kept in storage tanks. Exposure to UV light did not affect either formation or removal of TTHM. The relative production of TTHM during warm and cold seasons was also evaluated. TTHM production decreased with higher temperatures, but that could be attributed to the increase of ammonia nitrogen concentration observed during the warm summer seasons. PMID:17585988

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

    International Nuclear Information System (INIS)

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

  9. Pilot-scale study of removal effect on Chironomid larvae with chlorine dioxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Chironomid larvae propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfection process like chlorination due to its stronger resistance to oxidation. In this paper, a pilot-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Chironomid larvae removal was conducted in Shenzhen Waterworks in Guangdong Province, China. The experimental results were compared with that of the existing prechlorination process in several aspects, including the Chironomid larvae removal efficiencies of water samples taken from the outlets of sedimentation tank, sand filter, the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Chironomid larvae than chlorine and Chironomid larvae could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that ofprechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.

  10. Aqueous chlorination of acebutolol: kinetics, transformation by-products, and mechanism.

    Science.gov (United States)

    Khalit, Wan Nor Adira Wan; Tay, Kheng Soo

    2016-02-01

    This study investigated the reaction kinetics and the transformation by-products of acebutolol during aqueous chlorination. Acebutolol is one of the commonly used β-blockers for the treatment of cardiovascular diseases. It has been frequently detected in the aquatic environment. In the kinetics study, the second-order rate constant for the reaction between acebutolol and chlorine (k app) was determined at 25 ± 0.1 °C. The degradation of acebutolol by free available chlorine was highly pH dependence. When the pH increased from 6 to 8, it was found that the k app for the reaction between acebutolol and free available chlorine was increased from 1.68 to 11.2 M(-1) min(-1). By comparing with the reported k app values, the reactivity of acebutolol toward free available chlorine was found to be higher than atenolol and metoprolol but lower than nadolol and propranolol. Characterization of the transformation by-products formed during the chlorination of acebutolol was carried out using liquid chromatography-quadrupole time-of-flight high-resolution mass spectrometry. Seven major transformation by-products were identified. These transformation by-products were mainly formed through dealkylation, hydroxylation, chlorination, and oxidation reactions. PMID:26423291

  11. separation of thorium from the rare earth elements by chlorination in Eskisehir-Beylikahir ore

    International Nuclear Information System (INIS)

    There are 3 fissionable isotopes for nuclear energy generation and these are ''2''3''5U, ''2''3''9Pu, 233U.233U has the highest neutron yield of these three isotopes. 235U has the lowest neutron yield is issued widely as a fuel in nuclear reactors because it occurs in nature.233U is produced by irradiation of thorium in reactors. Bastnasit are containing rare earths, in eskisehir, Turkey, also contains Th. Th content and its composition differ according to the area. In this study chlorination of the ores of various content is proposed for separation of the Th from rare earths in place of the conventional acid and alkaline leach methods.The ore is crushed and grinded under 75 micrometers and mixed with C at 1:1 ratio for chlorination. This mixture is humidified and dried in a drying oven. The caked mixture is then chlorinated in a chlorination furnace. Particle size of thorium ore, chlorination time and temperature, ore/carbon ratio of the mixture, choline gas flow rate, Th content of the ore are parameters affecting the chlorination yield. Fluorite mineral in the ore decreases the chlorination yield

  12. Direct Chlorination Process for geothermal power plant off-gas - hydrogen sulfide abatement

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.

    1983-06-01

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

  13. Oxidative Dissolution of Silver Nanoparticles by Chlorine: Implications to Silver Nanoparticle Fate and Toxicity.

    Science.gov (United States)

    Garg, Shikha; Rong, Hongyan; Miller, Christopher J; Waite, T David

    2016-04-01

    The kinetics of oxidative dissolution of silver nanoparticles (AgNPs) by chlorine is investigated in this work, with results showing that AgNPs are oxidized in the presence of chlorine at a much faster rate than observed in the presence of dioxygen and/or hydrogen peroxide. The oxidation of AgNPs by chlorine occurs in air-saturated solution in stoichiometric amounts with 2 mol of AgNPs oxidized for each mole of chlorine added. Dioxygen plays an important role in OCl(-)-mediated AgNP oxidation, especially at lower OCl(-) concentrations, with the mechanism shifting from stoichiometric oxidation of AgNPs by OCl(-) in the presence of dioxygen to catalytic removal of OCl(-) by AgNPs in the absence of dioxygen. These results suggest that the presence of chlorine will mitigate AgNP toxicity by forming less-reactive AgCl(s) following AgNP oxidation, although the disinfection efficiency of OCl(-) may not be significantly impacted by the presence of AgNPs because a chlorine-containing species is formed on OCl(-) decay that has significant oxidizing capacity. Our results further suggest that the antibacterial efficacy of nanosilver particles embedded on fabrics may be negated when treated with detergents containing strong oxidants, such as chlorine. PMID:26986484

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

    International Nuclear Information System (INIS)

    The remelting of automobile scrap in an electric arc furnace (EAF) results in the production of a dust, which contains high concentrations of the oxides of zinc, iron, calcium and other metals. Typically, the lead and zinc are of commercial value, while the other metals are not worth recovering. At the present time, EAF dusts are treated in high temperature Waelz rotary kiln-type processes, where the lead and zinc oxides are selectively reduced and simultaneously reoxidized and a crude zinc oxide is produced. Another alternative processing route is selective chlorination, in which the non-ferrous metals are preferentially chlorinated to their gaseous chlorides and in this manner separated from the iron. In the present research, a detailed thermodynamic analysis of this chlorination process has been performed and the following factors were investigated; temperature, amount of chlorine, lime content, silica content, presence of an inert gas and the oxygen potential. High lead and zinc recoveries as gaseous chlorides could be achieved but some of the iron oxide was also chlorinated. Additionally, the calcium oxide in the dust consumes chlorine, but this can be minimized by adding silica, which results in the formation of stable calcium silicates. The optimum conditions were determined for a typical dust composition. The selectivities achieved with chlorination were lower than those for reduction, as reported in the literature, but there are other advantages such as the potential recovery of copper.

  15. Factors affecting trihalomethane formation and speciation during chlorination of reclaimed water.

    Science.gov (United States)

    Ma, Defang; Gao, Baoyu; Wang, Yan; Yue, Qinyan; Li, Qian

    2015-01-01

    A hybrid process with membrane bioreactor (MBR) and powdered activated carbon (PAC), PAC/MBR, was used for real municipal wastewater treatment and reuse. The roles of chlorine dose, contact time, pH and bromide in trihalomethane (THM) formation and speciation during chlorination of the reclaimed water were investigated. Total trihalomethane (TTHM) yield exponentially increased to maximum with increasing chlorine dose (correlation coefficient R2=0.98). Prolonging substrate chlorine contact time significantly promoted TTHM formation. Less than 40% of THMs formed in the first 24 h, indicating that the PAC/MBR effluent organic matters were mostly composed of slow-reacting precursors. Increasing pH and bromide concentration facilitated THM formation. Higher chlorine dose and contact time enhanced chloro-THM formation. The bromo-THM formation was favored at near neutral condition. Despite the variation of chlorine dose, contact time and pH, the yield of THM species in order was usually CHCl3>CHBrCl2>CHBr2Cl>CHBr3. However, THM speciation shifted from chlorinated species to brominated species with increasing bromide concentration. PMID:26247761

  16. Effects of Strong Electronic Coupling in Chlorin and Bacteriochlorin Dyads.

    Science.gov (United States)

    Kang, Hyun Suk; Esemoto, Nopondo N; Diers, James R; Niedzwiedzki, Dariusz M; Greco, Jordan A; Akhigbe, Joshua; Yu, Zhanqian; Pancholi, Chirag; Bhagavathy, Ganga Viswanathan; Nguyen, Jamie K; Kirmaier, Christine; Birge, Robert R; Ptaszek, Marcin; Holten, Dewey; Bocian, David F

    2016-01-28

    Achieving tunable, intense near-infrared absorption in molecular architectures with properties suitable for solar light harvesting and biomedical studies is of fundamental interest. Herein, we report the photophysical, redox, and molecular-orbital characteristics of nine hydroporphyrin dyads and associated benchmark monomers that have been designed and synthesized to attain enhanced light harvesting. Each dyad contains two identical hydroporphyrins (chlorin or bacteriochlorin) connected by a linker (ethynyl or butadiynyl) at the macrocycle β-pyrrole (3- or 13-) or meso (15-) positions. The strong electronic communication between constituent chromophores is indicated by the doubling of prominent absorption features, split redox waves, and paired linear combinations of frontier molecular orbitals. Relative to the benchmarks, the chlorin dyads in toluene show substantial bathochromic shifts of the long-wavelength absorption band (17-31 nm), modestly reduced singlet excited-state lifetimes (τS = 3.6-6.2 ns vs 8.8-12.3 ns), and increased fluorescence quantum yields (Φf = 0.37-0.57 vs 0.34-0.39). The bacteriochlorin dyads in toluene show significant bathochromic shifts (25-57 nm) and modestly reduced τS (1.6-3.4 ns vs 3.5-5.3 ns) and Φf (0.09-0.19 vs 0.17-0.21) values. The τS and Φf values for the bacteriochlorin dyads are reduced substantially (up to ∼20-fold) in benzonitrile. The quenching is due primarily to the increased S1 → S0 internal conversion that is likely induced by increased contribution of charge-resonance configurations to the S1 excited state in the polar medium. The fundamental insights gained into the physicochemical properties of the strongly coupled hydroporphyrin dyads may aid their utilization in solar-energy conversion and photomedicine. PMID:26765839

  17. Sorption of iodine, chlorine, technetium and cesium in soil

    International Nuclear Information System (INIS)

    The safety assessment of final disposal of spent nuclear fuel will include an estimate for the behavior of waste nuclides in the biosphere. As a part of this estimate also the sorption of radioactive iodine, chlorine, technetium and cesium in soil is to be considered. The chemistry and the sorption of these radionuclides in soils are described in this literature survey. Behavior of I-129, Cl-36 and Tc-99 in the environment is of great interest because of their long half-lives and relatively high mobilities. The importance of Cs-135 arises from its high content in spent nuclear fuel and long physical half-life, even though it is considered relatively immobile in soil. Factors affecting the migration and sorption of radionuclides in soils can be divided into elemental and soil specific parameters. The most important elemental factor is the speciation of the element, which is influenced by the soil redox potential, pH and complex forming ligands. Soil micro-organisms can either serve as sorbents for radionuclides or affect their speciation by altering the prevailing soil redox conditions. Soil organic matter content and mineral properties have a marked influence on the retention of radionuclides. The sorption of anionic radionuclides such as I-, Cl- and TcO4 - is pronounced in the presence of organic matter. Clay minerals are known to bound cesium effectively. The effect of speciation of radioactive iodine, chlorine, technetium and cesium in soil is considered in this study, as well as the effect of soil micro-organisms, organic matter and mineral properties. (orig.)

  18. Hydrochloric acid and the chlorine budget of the lower statosphere

    Science.gov (United States)

    Webster, C. R.; May, R. D.; Jaegle, L.; Hu, H.; Sander, S. P.; Gunson, M. R.; Toon, G. C.; Russell, J. M., III; Stimpfle, R. M.; Koplow, J. P.

    1994-01-01

    Concentrations of HCl measurements in the lower stratosphere in 1993 by the ALIAS instrument on the ER-2 aircraft reveal that only 40% of inorganic chlorine (Cl(y), inferred from in situ measurements of organic chlorinated sources gases) is present as HCl, significantly lower than model predictions. Although the sum of measured HCl, ClO and ClONO2, the latter inferred from measurements of ClO and NO2 equals Cl(y) to within the incertainty of measurement, it is systematically less than Cl(y) by 30-50%. This discrepancy suggests that concentrations of ClONO2 may exceed those of HC; near 20 km altitude, consistent with a slower photolysis rate for ClONO2 than calculated using recommended cross sections. Comparison of profiles of HCl measured during 1992 and 1193 at mid-latitudes by balloon (BLISS and MARKIV), space shuttle (ATMOS), and satellite (HALOE) instruments with the aircraft data reveal an apparent pressure dependence to the HCl to Cl(y) ratio, consistent with a factor of 3-10 reduction in the photolysis rate for ClONO2 at ER-2 altitudes. However, the diurnal variation of ClO is well-simulated by models using the recommended photolysis rate, and simulations measurements of ClONO2 and HCl at mid-latitudes by ATMOS and MARKIV report HCl (HCL+ ClONO2) ratios greater than or equal to 50%. Premliminary measurements by ALIAS in the southern hemisphere report HCl/Cl(y) values of about 75%.

  19. Variation in yield ratios of fragment ions and of ion-pairs from CF2Cl2 following monochromatic soft X-ray absorption

    International Nuclear Information System (INIS)

    Fragment ions produced from CF2Cl2 have been measured from 44 to 1200eV using a time-of-flight mass spectrometer and monochromatized synchrotron radiation. Positively charged ion pairs from this molecule were observed in the inner-shell excitation regions using a Selected photoion-photoion coincidence technique. Obtained yield ratios of fragment ions indicate that the atomic chlorine ion, Cl+, has the greatest intensity at all photon energies above 60eV and exhibits a steep increase at the Cl L2,3 -edges. Some fragment ions, in particular CF2+, have a clear intensity increase at the transitions of inner-shell electrons to unoccupied molecular orbitals. The ion pair F+ - Cl+ exhibits the highest yield at most photon energies, and some of the branching ratios for ion-pair production changed significantly near the Cl L2,3 -edges. (author)

  20. Chlorine dioxide as phenol and H2S scavenger - formation of halogenated phenols and subsequent environmental risk

    Energy Technology Data Exchange (ETDEWEB)

    Melbye, Alf G.; Faksness, Liv-Guri; Knudsen, Boerre Leif

    2006-03-15

    Formation of halogenated phenols as side products from treatment of produced water with aqueous chlorine dioxide has been investigated. The literature describes formation of halogenated hydrocarbons in effluent treatment using chlorine, hypochlorite and chlorine dioxide. A new chlorine dioxide product, originally intended as a H2S scavenger in the oil and gas industry, has been tested both as a phenol scavenger and H2S-scavenger for produced water applications. The concern about the possible formation of halogenated by-products initiated laboratory testing of chlorine dioxide as phenol and H2S scavenger for produced water applications. The tests also included synthetic matrixes containing phenols, and the tests show that halogenated phenols, mainly brominated species, are found in produced water after treatment with chlorine dioxide. Due to potential environmental risk from halogenated organic contaminants, the use of chlorine dioxide as phenol and H2S scavenger is not recommended. (Author)