Dechlorination of the dietary nona-chlorinated toxaphene congeners 62 and 50 into the octa-chlorinated toxaphene congeners 44 and 40 in zebrafish (Danio rerio) and Atlantic salmon (Salmo salar)

International Nuclear Information System (INIS)

Berntssen, M.H.G.; Lundebye, A.-K.; Hop-Johannessen, L.; Lock, E.-J.

2012-01-01

Graphical abstract: - Abstract: The relative feed-to-fish accumulation and possible biotransformation of the nona-chlorinated toxaphene congeners currently included in EU-legislation (CHB-50 and -62) and the octa-chlorinated congeners recommended by the European Food Safety Authority to be included in future surveillance of fish samples (CHB-40, 41, and 44) were investigated in the present study. Model fish Danio rerio were fed either (a) diets spiked with a combination as well as the pure individual toxaphene congeners CHB-50 or 62 or (b) diets spiked with the combination of CHB ∑50 + 62 and/or CHB ∑40 + 41 + 44. In addition, seawater adapted Atlantic salmon smolts were fed technical toxaphene enriched feeds for 62 days. Zebrafish fed a diet containing CHB-50 and CHB-62 accumulated newly formed CHB-40 and 41 and CHB-44, respectively. The biomagnifications factors (BMF) of the toxaphene congeners in Atlantic salmon muscle from the feeds spiked with technical toxaphene were significantly correlated with their relative lipophilicity (expressed as log K ow ). An exception was CHB-44 which had a higher BMF than could be expected from its specific log K ow , reflecting that CHB-44 is a metabolite formed under dietary exposure to CHB-62. This paper reports the in vivo dechlorination of nona-chlorinated toxaphene congeners into octa-chlorinated congeners in feeding trials with a model fish (zebrafish) and an oily food fish (Atlantic salmon).

Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Foley, D.M. E-mail: dfoley@chapman.edu; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A

2002-03-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10{sup 7} CFU/g. Following chlorination at 200 {mu}g/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a {sup 60}Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service.

Reduction of Escherichia coli 0157:H7 in shredded iceberg lettuce by chlorination and gamma irradiation

International Nuclear Information System (INIS)

Foley, D.M.; Dufour, A.; Rodriguez, L.; Caporaso, F.; Prakash, A.

2002-01-01

Lettuce was inoculated with a six-strain cocktail of acid-adapted Escherichia coli 0157:H7 at a level of 1x10 7 CFU/g. Following chlorination at 200 μg/ml, the lettuce was irradiated at 0.15, 0.38, or 0.55 kGy using a 60 Co source. Survival of E. coli 0157:H7, aerobic mesophiles and yeast and molds were measured over a period of 10 days. For quality analysis, chlorinated lettuce was subjected to irradiation at 0.33 and 0.53 kGy and stored at 1.0 deg. C, 4.0 deg. C or 7.0 deg. C. Changes in texture and color were determined by instrumental means and changes in flavor, odor, and visual quality were determined by sensory testing. Chlorination plus irradiation at 0.55 kGy produced a 5.4-log reduction in E. coli 0157:H7 levels. Chlorination alone reduced the E. coli 0157:H7 counts by 1-2 logs. Irradiation at 0.55 kGy was also effective in reducing standard plate counts and yeast and mold counts. Irradiation at this level did not cause softening of lettuce and sensory attributes were not adversely affected. In general, appearance and flavor were affected more by the length of storage than by temperature conditions. The 5+log reduction in E. coli counts and lack of adverse effects on sensory attributes indicate that low-dose irradiation can improve the safety and shelf-life of fresh-cut iceberg lettuce for retail sale or food service

WHIM-3D-QSPR APPROACH FOR PREDICTING AQUEOUS SOLUBILITY OF CHLORINATED HYDROCARBONS

Directory of Open Access Journals (Sweden)

Oman Zuas

2010-06-01

Full Text Available The weighted holistic invariant molecular-three dimensional-quantitative structure property relationship (WHIM-3D-QSPR approach has been applied to the study of the aqueous solubility (- log Sw of chlorinated hydrocarbon compounds (CHC's. The obtained QSPR model is predictive and only requires four WHIM-3D descriptors in the calculation. The correlation equation of the model that is based on a training set of 50 CHC's compound has statistical parameters: standard coefficient correlation (R2 = 0.948; cross-validated correlation coefficients (Q2 = 0.935; Standard Error of Validation (SEV = 0.35; and average absolute error (AAE = 0.31. The application of the best model to a testing set of 50 CHC's demonstrates a reliable result with good predictability. Besides, it was possible to construct new model by applying WHIM-3D-QSPR approach without require any experimental physicochemical properties in the calculation of aqueous solubility.   Keywords: WHIM-3D; QSPR; aqueous solubility; - Log Sw, chlorinated hydrocarbons, CHC's

Comparison of the disinfection efficacy of chlorine-based products for inactivation of viral indicators and pathogenic bacteria in produce wash water.

Science.gov (United States)

Chaidez, Cristobal; Moreno, Maria; Rubio, Werner; Angulo, Miguel; Valdez, Benigno

2003-09-01

Outbreaks of pathogenic bacteria infections associated with the consumption of fresh produce has occurred with increased frequency in recent years. This study was undertaken to determine the efficacy of three commonly used disinfectants in packing-houses of Culiacan, Mexico (sodium hypochlorite [NaOCl], trichlor-s-triazinetrione [TST] and thrichlormelamine [TCM]) for inactivation of viral indicators and pathogenic bacteria inoculated onto produce wash water. Each microbial challenge consisted of 2 L of water containing approximately 8 log10 bacterial CFU ml(-1), and 8 log10 viral PFU ml(-1) treated with 100 and 300 mg l(-1) of total chlorine with modified turbidity. Water samples were taken after 2 min of contact with chlorine-based products and assayed for the particular microorganisms. TST and NaOCl were found to effectively reduce for bacterial pathogens and viral indicators 8 log10 and 7 log10, respectively (alpha=0.05). The highest inactivation rate was observed when the turbidity was low and the disinfectant was applied at 300 mg l(-1). TCM did not show effective results when compared with the TST and NaOCl (Pturbidity created by the organic and inorganic material present in the water tanks carried by the fresh produce may affect the efficacy of the chlorine-based products.

Effect of chlorine treatment on inhibition of E. coli serogroup O2 incorporation into 7-day-old biofilm on polyvinylchloride surface.

Science.gov (United States)

Maharjan, P; Dey, S; Huff, G; Zhang, W; Phillips, G K; Watkins, S

2017-08-01

Poultry waterlines are constructed using polyvinylchloride (PVC) material on which bacterial biofilm can easily form. Biofilm can harbor pathogens including avian pathogenic E. coli (APEC) strains. An in vitro evaluation was performed to determine if E. coli sero group O2 (avian pathogenic) could attach on a PVC surface that had pre-formed biofilm and if this phenomenon could be affected when water was treated with chlorine. Initially, biofilm growth was induced in PVC test coupons (15.16 cm2) for a 7-day period mimicking the waterline scenario in the first wk of poultry brooding; and then this biofilm was challenged with E. coli O2 seeded water in presence/absence of chlorine treatment. After rinsing, test coupons were sampled for bacterial (APC) and E. coli O2 enumeration at various occasions post seeding the pathogen and chlorine treatment. Day 7 APC recovered from coupons was 4.35 log10 cfu/cm2 in trial 1 and 3.66 log10 cfu/cm2 in trial 2. E. coli O2 was not recovered from chlorine treated test coupons (P  3 log10 cfu/cm2 in trial 1 and > 2 log10 cfu/cm2 in trial 2). This study suggests that E. coli O2 can incorporate into pre-formed biofilm on a PVC surface within 24 h if water sanitation is not present, and the attachment time of the pathogen can prolong in the absence of already formed biofilm. © 2017 Poultry Science Association Inc.

Studies with solid chlorine chemical for chlorination of sea water systems

International Nuclear Information System (INIS)

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

2015-01-01

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

The effect of pH and chloride concentration on the stability and antimicrobial activity of chlorine-based sanitizers.

Science.gov (United States)

Waters, Brian W; Hung, Yen-Con

2014-04-01

Chlorinated water and electrolyzed oxidizing (EO) water solutions were made to compare the free chlorine stability and microbicidal efficacy of chlorine-containing solutions with different properties. Reduction of Escherichia coli O157:H7 was greatest in fresh samples (approximately 9.0 log CFU/mL reduction). Chlorine loss in "aged" samples (samples left in open bottles) was greatest (approximately 40 mg/L free chlorine loss in 24 h) in low pH (approximately 2.5) and high chloride (Cl(-) ) concentrations (greater than 150 mg/L). Reduction of E. coli O157:H7 was also negatively impacted (pH and high Cl(-) . Higher pH values (approximately 6.0) did not appear to have a significant effect on free chlorine loss or numbers of surviving microbial cells when fresh and aged samples were compared. This study found chloride levels in the chlorinated and EO water solutions had a reduced effect on both free chlorine stability and its microbicidal efficacy in the low pH solutions. Greater concentrations of chloride in pH 2.5 samples resulted in decreased free chlorine stability and lower microbicidal efficacy. © 2014 Institute of Food Technologists®

Comparative assessment of chlorine, heat, ozone, and UV light for killing Legionella pneumophila within a model plumbing system

International Nuclear Information System (INIS)

Muraca, P.; Stout, J.E.; Yu, V.L.

1987-01-01

Nosocomial Legionnaires disease can be acquired by exposure to the organism from the hospital water distribution system. As a result, many hospitals have instituted eradication procedures, including hypercholorination and thermal eradication. We compared the efficacy of ozonation, UV light, hyperchlorination, and heat eradication using a model plumbing system constructed of copper piping, brass spigots, Plexiglas reservoir, electric hot water tank, and a pump. Legionella pneumophila was added to the system at 10(7) CFU/ml. Each method was tested under three conditions; (i) nonturbid water at 25 degrees C, (ii) turbid water at 25 degrees C, and (iii) nonturbid water at 43 degrees C. UV light and heat killed L. pneumophila most rapidly and required minimal maintenance. Both UV light and heat (60 degrees C) produced a 5 log kill in less than 1 h. In contrast, both chlorine and ozone required 5 h of exposure to produce a 5 log decrease. Neither turbidity nor the higher temperature of 43 degrees C impaired the efficacy of any of the disinfectant methods. Surprisingly, higher temperature enhanced the disinfecting efficacy of chlorine. However, higher temperature accelerated the decomposition of the chlorine residual such that an additional 120% volume of chlorine was required. All four methods proved efficacious in eradicating L. pneumophila from a model plumbing system

Chlorination or monochloramination: Balancing the regulated trihalomethane formation and microbial inactivation in marine aquaculture waters

KAUST Repository

Sanawar, Huma; Xiong, Yanghui; Alam, Aftab; Croue, Jean-Philippe; Hong, Pei-Ying

2017-01-01

at the lowest tested concentration of chlorine (1mg/L) and contact time (1h). Comparatively, regulated THMs concentration was only detectable at 30μg/L level in one of the three sets of monochloraminated marine aquaculture waters. The average log reduction

Nuclear Well Log Properties of Natural Gas Hydrate Reservoirs

Science.gov (United States)

Burchwell, A.; Cook, A.

2015-12-01

Characterizing gas hydrate in a reservoir typically involves a full suite of geophysical well logs. The most common method involves using resistivity measurements to quantify the decrease in electrically conductive water when replaced with gas hydrate. Compressional velocity measurements are also used because the gas hydrate significantly strengthens the moduli of the sediment. At many gas hydrate sites, nuclear well logs, which include the photoelectric effect, formation sigma, carbon/oxygen ratio and neutron porosity, are also collected but often not used. In fact, the nuclear response of a gas hydrate reservoir is not known. In this research we will focus on the nuclear log response in gas hydrate reservoirs at the Mallik Field at the Mackenzie Delta, Northwest Territories, Canada, and the Gas Hydrate Joint Industry Project Leg 2 sites in the northern Gulf of Mexico. Nuclear logs may add increased robustness to the investigation into the properties of gas hydrates and some types of logs may offer an opportunity to distinguish between gas hydrate and permafrost. For example, a true formation sigma log measures the thermal neutron capture cross section of a formation and pore constituents; it is especially sensitive to hydrogen and chlorine in the pore space. Chlorine has a high absorption potential, and is used to determine the amount of saline water within pore spaces. Gas hydrate offers a difference in elemental composition compared to water-saturated intervals. Thus, in permafrost areas, the carbon/oxygen ratio may vary between gas hydrate and permafrost, due to the increase of carbon in gas hydrate accumulations. At the Mallik site, we observe a hydrate-bearing sand (1085-1107 m) above a water-bearing sand (1107-1140 m), which was confirmed through core samples and mud gas analysis. We observe a decrease in the photoelectric absorption of ~0.5 barnes/e-, as well as an increase in the formation sigma readings of ~5 capture units in the water-bearing sand as

Lethality of chlorine, chlorine dioxide, and a commercial fruit and vegetable sanitizer to vegetative cells and spores of Bacillus cereus and spores of Bacillus thuringiensis.

Science.gov (United States)

Beuchat, Larry R; Pettigrew, Charles A; Tremblay, Mario E; Roselle, Brian J; Scouten, Alan J

2004-08-01

Chlorine, ClO2, and a commercial raw fruit and vegetable sanitizer were evaluated for their effectiveness in killing vegetative cells and spores of Bacillus cereus and spores of Bacillus thuringiensis. The ultimate goal was to use one or both species as a potential surrogate(s) for Bacillus anthracis in studies that focus on determining the efficacy of sanitizers in killing the pathogen on food contact surfaces and foods. Treatment with alkaline (pH 10.5 to 11.0) ClO2 (200 microg/ml) produced by electrochemical technologies reduced populations of a five-strain mixture of vegetative cells and a five-strain mixture of spores of B. cereus by more than 5.4 and more than 6.4 log CFU/ml respectively, within 5 min. This finding compares with respective reductions of 4.5 and 1.8 log CFU/ml resulting from treatment with 200 microg/ml of chlorine. Treatment with a 1.5% acidified (pH 3.0) solution of Fit powder product was less effective, causing 2.5- and 0.4-log CFU/ml reductions in the number of B. cereus cells and spores, respectively. Treatment with alkaline ClO2 (85 microg/ml), acidified (pH 3.4) ClO2 (85 microg/ml), and a mixture of ClO2 (85 microg/ml) and Fit powder product (0.5%) (pH 3.5) caused reductions in vegetative cell/spore populations of more than 5.3/5.6, 5.3/5.7, and 5.3/6.0 log CFU/ml, respectively. Treatment of B. cereus and B. thuringiensis spores in a medium (3.4 mg/ml of organic and inorganic solids) in which cells had grown and produced spores with an equal volume of alkaline (pH 12.1) ClO2 (400 microg/ml) for 30 min reduced populations by 4.6 and 5.2 log CFU/ml, respectively, indicating high lethality in the presence of materials other than spores that would potentially react with and neutralize the sporicidal activity of ClO2.

Photodynamic tissue adhesion with chlorin(e6) protein conjugates.

Science.gov (United States)

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

1999-12-01

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

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

Science.gov (United States)

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

2016-12-20

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

Aggregation of Adenovirus 2 in Source Water and Impacts on Disinfection by Chlorine

Science.gov (United States)

Cromeans, Theresa L.; Metcalfe, Maureen G.; Humphrey, Charles D.; Hill, Vincent R.

2016-01-01

It is generally accepted that viral particles in source water are likely to be found as aggregates attached to other particles. For this reason, it is important to investigate the disinfection efficacy of chlorine on aggregated viruses. A method to produce adenovirus particle aggregation was developed for this study. Negative stain electron microscopy was used to measure aggregation before and after addition of virus particles to surface water at different pH and specific conductance levels. The impact of aggregation on the efficacy of chlorine disinfection was also examined. Disinfection experiments with human adenovirus 2 (HAdV2) in source water were conducted using 0.2 mg/L free chlorine at 5 °C. Aggregation of HAdV2 in source water (≥3 aggregated particles) remained higher at higher specific conductance and pH levels. However, aggregation was highly variable, with the percentage of particles present in aggregates ranging from 43 to 71 %. Upon addition into source water, the aggregation percentage dropped dramatically. On average, chlorination CT values (chlorine concentration in mg/L × time in min) for 3-log10 inactivation of aggregated HAdV2 were up to three times higher than those for dispersed HAdV2, indicating that aggregation reduced the disinfection rate. This information can be used by water utilities and regulators to guide decision making regarding disinfection of viruses in water. PMID:26910058

Microbial community response to chlorine conversion in a chloraminated drinking water distribution system.

Science.gov (United States)

Wang, Hong; Proctor, Caitlin R; Edwards, Marc A; Pryor, Marsha; Santo Domingo, Jorge W; Ryu, Hodon; Camper, Anne K; Olson, Andrew; Pruden, Amy

2014-09-16

Temporary conversion to chlorine (i.e., "chlorine burn") is a common approach to controlling nitrification in chloraminated drinking water distribution systems, yet its effectiveness and mode(s) of action are not fully understood. This study characterized occurrence of nitrifying populations before, during and after a chlorine burn at 46 sites in a chloraminated distribution system with varying pipe materials and levels of observed nitrification. Quantitative polymerase chain reaction analysis of gene markers present in nitrifying populations indicated higher frequency of detection of ammonia oxidizing bacteria (AOB) (72% of samples) relative to ammonia oxidizing archaea (AOA) (28% of samples). Nitrospira nitrite oxidizing bacteria (NOB) were detected at 45% of samples, while presence of Nitrobacter NOB could not be confirmed at any of the samples. During the chlorine burn, the numbers of AOA, AOB, and Nitrospira greatly reduced (i.e., 0.8-2.4 log). However, rapid and continued regrowth of AOB and Nitrospira were observed along with nitrite production in the bulk water within four months after the chlorine burn, and nitrification outbreaks appeared to worsen 6-12 months later, even after adopting a twice annual burn program. Although high throughput sequencing of 16S rRNA genes revealed a distinct community shift and higher diversity index during the chlorine burn, it steadily returned towards a condition more similar to pre-burn than burn stage. Significant factors associated with nitrifier and microbial community composition included water age and sampling location type, but not pipe material. Overall, these results indicate that there is limited long-term effect of chlorine burns on nitrifying populations and the broader microbial community.

A spore counting method and cell culture model for chlorine disinfection studies of Encephalitozoon syn. Septata intestinalis.

Science.gov (United States)

Wolk, D M; Johnson, C H; Rice, E W; Marshall, M M; Grahn, K F; Plummer, C B; Sterling, C R

2000-04-01

The microsporidia have recently been recognized as a group of pathogens that have potential for waterborne transmission; however, little is known about the effects of routine disinfection on microsporidian spore viability. In this study, in vitro growth of Encephalitozoon syn. Septata intestinalis, a microsporidium found in the human gut, was used as a model to assess the effect of chlorine on the infectivity and viability of microsporidian spores. Spore inoculum concentrations were determined by using spectrophotometric measurements (percent transmittance at 625 nm) and by traditional hemacytometer counting. To determine quantitative dose-response data for spore infectivity, we optimized a rabbit kidney cell culture system in 24-well plates, which facilitated calculation of a 50% tissue culture infective dose (TCID(50)) and a minimal infective dose (MID) for E. intestinalis. The TCID(50) is a quantitative measure of infectivity and growth and is the number of organisms that must be present to infect 50% of the cell culture wells tested. The MID is as a measure of a system's permissiveness to infection and a measure of spore infectivity. A standardized MID and a standardized TCID(50) have not been reported previously for any microsporidian species. Both types of doses are reported in this paper, and the values were used to evaluate the effects of chlorine disinfection on the in vitro growth of microsporidia. Spores were treated with chlorine at concentrations of 0, 1, 2, 5, and 10 mg/liter. The exposure times ranged from 0 to 80 min at 25 degrees C and pH 7. MID data for E. intestinalis were compared before and after chlorine disinfection. A 3-log reduction (99.9% inhibition) in the E. intestinalis MID was observed at a chlorine concentration of 2 mg/liter after a minimum exposure time of 16 min. The log(10) reduction results based on percent transmittance-derived spore counts were equivalent to the results based on hemacytometer-derived spore counts. Our data

Viable-but-Nonculturable Listeria monocytogenes and Salmonella enterica Serovar Thompson Induced by Chlorine Stress Remain Infectious

Directory of Open Access Journals (Sweden)

Callum J. Highmore

2018-04-01

Full Text Available The microbiological safety of fresh produce is monitored almost exclusively by culture-based detection methods. However, bacterial food-borne pathogens are known to enter a viable-but-nonculturable (VBNC state in response to environmental stresses such as chlorine, which is commonly used for fresh produce decontamination. Here, complete VBNC induction of green fluorescent protein-tagged Listeria monocytogenes and Salmonella enterica serovar Thompson was achieved by exposure to 12 and 3 ppm chlorine, respectively. The pathogens were subjected to chlorine washing following incubation on spinach leaves. Culture data revealed that total viable L. monocytogenes and Salmonella Thompson populations became VBNC by 50 and 100 ppm chlorine, respectively, while enumeration by direct viable counting found that chlorine caused a <1-log reduction in viability. The pathogenicity of chlorine-induced VBNC L. monocytogenes and Salmonella Thompson was assessed by using Caenorhabditis elegans. Ingestion of VBNC pathogens by C. elegans resulted in a significant life span reduction (P = 0.0064 and P < 0.0001, and no significant difference between the life span reductions caused by the VBNC and culturable L. monocytogenes treatments was observed. L. monocytogenes was visualized beyond the nematode intestinal lumen, indicating resuscitation and cell invasion. These data emphasize the risk that VBNC food-borne pathogens could pose to public health should they continue to go undetected.

Chlorine in the stratosphere

OpenAIRE

VON CLARMANN, T.

2013-01-01

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

Quantification of pathogen inactivation efficacy by free chlorine disinfection of drinking water for QMRA.

Science.gov (United States)

Petterson, S R; Stenström, T A

2015-09-01

To support the implementation of quantitative microbial risk assessment (QMRA) for managing infectious risks associated with drinking water systems, a simple modeling approach for quantifying Log10 reduction across a free chlorine disinfection contactor was developed. The study was undertaken in three stages: firstly, review of the laboratory studies published in the literature; secondly, development of a conceptual approach to apply the laboratory studies to full-scale conditions; and finally implementation of the calculations for a hypothetical case study system. The developed model explicitly accounted for variability in residence time and pathogen specific chlorine sensitivity. Survival functions were constructed for a range of pathogens relying on the upper bound of the reported data transformed to a common metric. The application of the model within a hypothetical case study demonstrated the importance of accounting for variable residence time in QMRA. While the overall Log10 reduction may appear high, small parcels of water with short residence time can compromise the overall performance of the barrier. While theoretically simple, the approach presented is of great value for undertaking an initial assessment of a full-scale disinfection contactor based on limited site-specific information.

Effect of chlorine on Mycobacterium gordonae and Mycobacterium chubuense in planktonic and Biofilm State

Directory of Open Access Journals (Sweden)

Alejandra Soledad Oriani

2018-01-01

Full Text Available Background: There is evidence that drinking water could be a source of infections with pathogenic nontuberculous mycobacteria (NTM potentially risky to human health. The aim was to investigate the resistance of two NTM isolated from drinking water, Mycobacterium gordonae and Mycobacterium chubuense, at different concentrations of chlorine (as sodium hypochlorite, used in drinking water sanitation. Methods: The NTM were grown in suspension and in biofilms and were challenged with biocide for 10 and 60 min. Results: To obtain 7-log reduction from the initial population of M. chubuense, in the planktonic state, there were necessary 20 ppm of chorine and 60 min of exposure. The same effect was achieved in M. gordonae with 10 ppm for the same period. The maximum reduction of both NTM in biofilm was 3-log reduction and was achieved using 30 ppm for 60 min. The chlorine susceptibility of cells in biofilms was significantly lower than that of planktonic cells. The results highlight the resistance of both NTM to the concentrations used in routine water sanitation (0.2 ppm according to Argentine Food Code. Differences in chlorine resistance found between the two NTM in planktonic growth decrease when they are grown in biofilm. Conclusion: This suggests that current water disinfection procedures do not always achieve effective control of NTM in the public supply system, with the consequent health risk to susceptible population, and the need to take into account biofilms, because of their deep consequences in the way to analyze the survival of prokaryotic cells in different environments.

Comparison of chlorine and chloramine in the release of mercury from dental amalgam.

Science.gov (United States)

Stone, Mark E; Scott, John W; Schultz, Stephen T; Berry, Denise L; Wilcoxon, Monte; Piwoni, Marv; Panno, Brent; Bordson, Gary

2009-01-01

The purpose of this project was to compare the ability of chlorine (HOCl/OCl(-)) and monochloramine (NH(2)Cl) to mobilize mercury from dental amalgam. Two types of amalgam were used in this investigation: laboratory-prepared amalgam and samples obtained from dental-unit wastewater. For disinfectant exposure simulations, 0.5 g of either the laboratory-generated or clinically obtained amalgam waste was added to 250 mL amber bottles. The amalgam samples were agitated by end-over-end rotation at 30 rpm in the presence of 1 mg/L chlorine, 10 mg/L chlorine, 1 mg/L monochloramine, 10 mg/L monochloramine, or deionized water for intervals of 0 h, 2 h, 4 h, 8 h, and 24 h for the clinically obtained amalgam waste samples and 4 h and 24 h for the laboratory-prepared samples. Chlorine and monochloramine concentrations were measured with a spectrophotometer. Samples were filtered through a 0.45 microm membrane filter and analyzed for mercury with USEPA standard method 245.7. When the two sample types were combined, the mean mercury level in the 1 mg/L chlorine group was 0.020 mg/L (n=25, SD=0.008). The 10 mg/L chlorine group had a mean mercury concentration of 0.59 mg/L (n=25, SD=1.06). The 1 mg/L chloramine group had a mean mercury level of 0.023 mg/L (n=25, SD=0.010). The 10 mg/L chloramine group had a mean mercury level of 0.024 mg/L (n=25, SD=0.011). Independent samples t-tests showed that there was a significant difference between the natural log mercury measurements of 10 mg/L chlorine compared to those of 1 mg/L and 10 mg/L chloramine. Changing from chlorine to chloramine disinfection at water treatment plants would not be expected to produce substantial increases in dissolved mercury levels in dental-unit wastewater.

Comparative Inactivation of Murine Norovirus, Human Adenovirus, and Human JC Polyomavirus by Chlorine in Seawater

Science.gov (United States)

de Abreu Corrêa, Adriana; Carratala, Anna; Barardi, Celia Regina Monte; Calvo, Miquel; Bofill-Mas, Sílvia

2012-01-01

Viruses excreted by humans affect the commercial and recreational use of coastal water. Shellfish produced in contaminated waters have been linked to many episodes and outbreaks of viral gastroenteritis, as well as other food-borne diseases worldwide. The risk can be reduced by appropriate treatment following harvesting and by depuration. The kinetics of inactivation of murine norovirus 1 and human adenovirus 2 in natural and artificial seawater by free available chlorine was studied by quantifying genomic copies (GC) using quantitative PCR and infectious viral particles (PFU). Human JC polyomavirus Mad4 kinetics were evaluated by quantitative PCR. DNase or RNase were used to eliminate free genomes and assess potential viral infectivity when molecular detection was performed. At 30 min of assay, human adenovirus 2 showed 2.6- and 2.7-log10 GC reductions and a 2.3- and 2.4-log10 PFU reductions in natural and artificial seawater, respectively, and infectious viral particles were still observed at the end of the assay. When DNase was used prior to the nucleic acid extraction the kinetic of inactivation obtained by quantitative PCR was statistically equivalent to the one observed by infectivity assays. For murine norovirus 1, 2.5, and 3.5-log10 GC reductions were observed in natural and artificial seawater, respectively, while no viruses remained infectious after 30 min of contact with chlorine. Regarding JC polyomavirus Mad4, 1.5- and 1.1-log10 GC reductions were observed after 30 min of contact time. No infectivity assays were conducted for this virus. The results obtained provide data that might be applicable to seawater used in shellfish depuration. PMID:22773637

Technology assessment: Chlorine chemistry

International Nuclear Information System (INIS)

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

1994-01-01

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

Chlorination and chloramines formation

International Nuclear Information System (INIS)

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

2008-01-01

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

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

International Nuclear Information System (INIS)

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

1976-01-01

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

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

International Nuclear Information System (INIS)

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

1995-01-01

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

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

NARCIS (Netherlands)

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

1985-01-01

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

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

Directory of Open Access Journals (Sweden)

Maliheh Akhlaghi

2018-06-01

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

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

Science.gov (United States)

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

2013-10-15

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

Study on removing chlorin by conversion-aborption of chlorin resin

International Nuclear Information System (INIS)

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

2012-01-01

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

Kinetics of molybdenum and chlorine interaction

International Nuclear Information System (INIS)

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

1977-01-01

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

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

Science.gov (United States)

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

2017-08-01

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

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

Science.gov (United States)

Fisher, Ian; Kastl, George; Sathasivan, Arumugam

2017-11-15

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

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

Science.gov (United States)

Han, A.; Raab, T. K.

2013-12-01

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

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

Science.gov (United States)

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

2007-08-01

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

Decontamination of Pangasius fish (Pangasius hypophthalmus) with chlorine or peracetic acid in the laboratory and in a Vietnamese processing company.

Science.gov (United States)

Tong Thi, Anh Ngoc; Sampers, Imca; Van Haute, Sam; Samapundo, Simbarashe; Ly Nguyen, Binh; Heyndrickx, Marc; Devlieghere, Frank

2015-09-02

This study evaluated the decontamination of Pangasius fillets in chlorine or peracetic acid treated wash water. First, the decontamination efficacy of the washing step with chlorinated water applied by a Vietnamese processing company during trimming of Pangasius fillets was evaluated and used as the basis for the experiments performed on a laboratory scale. As chlorine was only added at the beginning of the batch and used continuously without renewal for 239min; a rapid increase of the bacterial counts and a fast decrease of chlorine in the wash water were found. This could be explained by the rapid accumulation of organic matter (ca. 400mg O2/L of COD after only 24min). Secondly, for the experiments performed on a laboratory scale, a single batch approach (one batch of wash water for treating a fillet) was used. Chlorine and PAA were evaluated at 10, 20, 50 and 150ppm at contact times of 10, 20 and 240s. Washing with chlorine and PAA wash water resulted in a reduction of Escherichia coli on Pangasius fish which ranged from 0-1.0 and 0.4-1.4logCFU/g, respectively while less to no reduction of total psychrotrophic counts, lactic acid bacteria and coliforms on Pangasius fish was observed. However, in comparison to PAA, chlorine was lost rapidly. As an example, 53-83% of chlorine and 15-17% of PAA were lost after washing for 40s (COD=238.2±66.3mg O2/L). Peracetic acid can therefore be an alternative sanitizer. However, its higher cost will have to be taken into consideration. Where (cheaper) chlorine is used, the processors have to pay close attention to the residual chlorine level, pH and COD level during treatment for optimal efficacy. Copyright © 2015. Published by Elsevier B.V.

Virucidal Activity of Fogged Chlorine Dioxide- and Hydrogen Peroxide-Based Disinfectants against Human Norovirus and Its Surrogate, Feline Calicivirus, on Hard-to-Reach Surfaces

Directory of Open Access Journals (Sweden)

Naim Montazeri

2017-06-01

Full Text Available Human norovirus (NoV is the leading cause of foodborne illnesses in the United States. Norovirus is shed in high numbers in the feces and vomitous of infected individuals. Contact surfaces contaminated with bodily fluids harboring infectious virus particles serve as vehicles for pathogen transmission. Environmental stability of NoV and its resistance to many conventional disinfectants necessitate effective inactivation strategies to control the spread of virus. We investigated the efficacy of two commercial disinfectants, hydrogen peroxide (7.5% and a chlorine dioxide (0.2%-surfactant-based product using a fogging delivery system against human NoV GI.6 and GII.4 Sydney strains as well as the cultivable surrogate, feline calicivirus (FCV dried on stainless steel coupons. Log10 reductions in human NoV and FCV were calculated utilizing RNase RT-qPCR and infectivity (plaque assay, respectively. An improved antiviral activity of hydrogen peroxide as a function of disinfectant formulation concentration in the atmosphere was observed against both GII.4 and FCV. At 12.4 ml/m3, hydrogen peroxide achieved a respective 2.5 ± 0.1 and 2.7 ± 0.3 log10 reduction in GI.6 and GII.4 NoV genome copies, and a 4.3 ± 0.1 log10 reduction in infectious FCV within 5 min. At the same disinfectant formulation concentration, chlorine dioxide-surfactant-based product resulted in a respective 1.7 ± 0.2, 0.6 ± 0.0, and 2.4 ± 0.2 log10 reduction in GI.6, GII.4, and FCV within 10 min; however, increasing the disinfectant formulation concentration to 15.9 ml/m3 negatively impacted its efficacy. Fogging uniformly delivered the disinfectants throughout the room, and effectively decontaminated viruses on hard-to-reach surfaces. Hydrogen peroxide delivered by fog showed promising virucidal activity against FCV by meeting the United States EPA 4-log10 reduction criteria for an anti-noroviral disinfectant; however, fogged chlorine dioxide-surfactant-based product did not achieve

Where does Chlorine-36 go?

International Nuclear Information System (INIS)

Anon.

2000-01-01

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

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.

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

International Nuclear Information System (INIS)

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

1995-01-01

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

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.

Attachment of Escherichia coli O157:H7 in ground beef to meat grinders and survival after sanitation with chlorine and peroxyacetic acid.

Science.gov (United States)

Farrell, B L; Ronner, A B; Wong, A C

1998-07-01

The potential for transfer of Escherichia coli O157:H7 from contaminated ground beef to grinding equipment and the inactivation of attached cells during cleaning and sanitizing was examined. Chub-packed ground beef with lean:fat ratios of 75:25, 80:20 or 90:10 was inoculated with 6 log CFU/g or 2 log CFU/g E. coli O157:H7 strain FRIK 910. Samples were consecutively ground in a Hobart meat grinder with stainless steel (SS) chips (1 cm2) glued to the auger housing. Chips were harvested after grinding, detergent washing with or without manual scrubbing and rinsing, sanitizing in a chlorine or peroxyacetic acid sanitizer, and overnight storage. Survival of E. coli O157:H7 was evaluated both by plate count and enrichment in trypticase soy broth. Approximately 3 to 4 log CFU/cm2 were attached to the SS after grinding with all three fat contents. After washing and sanitizing in a chlorine or peroxyacetic acid sanitizer, viable bacteria were infrequently recovered by plate count. Enrichment of chips resulted in a higher survival rate with both sanitizing treatments, indicating that cell numbers below the limit of detection (5 CFU/cm2) or potentially injured organisms remained on the surface. Manual scrubbing during the washing step reduced the recovery rate. The scrubbing step also increased the number of passing scores assigned using an ATP bioluminescence assay of total residual soil on the chips sanitized in chlorine. The overall results indicate that plate counts alone may not be a reliable indicator of sanitation efficacy and may be validated by enrichment assay.

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

OpenAIRE

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

1997-01-01

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

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

Science.gov (United States)

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

2016-11-15

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

Alternative methods for chlorination

Energy Technology Data Exchange (ETDEWEB)

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

1985-12-01

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

Behavior of chlorine in lake water

International Nuclear Information System (INIS)

Sriraman, A.K.

2006-01-01

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

Quantifying Short-Chain Chlorinated Paraffin Congener Groups

NARCIS (Netherlands)

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

2017-01-01

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

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

Science.gov (United States)

Chen, Xi; Hung, Yen-Con

2018-05-22

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

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

Studies on chlorinated bromide salt for microfouling control

International Nuclear Information System (INIS)

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

1995-01-01

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

Chlorination of irradiated polyethylene single crystals

International Nuclear Information System (INIS)

Grimm, H.J.

1978-01-01

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

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

Science.gov (United States)

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

2011-02-01

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

Characterisation of Chlorine Behavior in French Graphite

International Nuclear Information System (INIS)

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

2016-01-01

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

Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water.

Directory of Open Access Journals (Sweden)

Marlene K Wolfe

Full Text Available To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS, and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions for 1 efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2 persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (p<0.001. Thus, chlorine-based methods may offer a benefit of reducing persistence in rinse water. We recommend responders use the most practical handwashing method to ensure hand hygiene in Ebola contexts, considering

Chlorine-36 investigations of salt lakes

International Nuclear Information System (INIS)

Chivas, A.R.; Kiss, E.

1987-01-01

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

Analysis of dechlorination kinetics of chlorinated aliphatic hydrocarbons by Fe(II) in cement slurries

Energy Technology Data Exchange (ETDEWEB)

Jung, Bahngmi [Department of Earth and Environmental Sciences, Wright State University, Dayton, OH 45435-0001 (United States)], E-mail: jung.bahngmi@gmail.com; Batchelor, Bill [Department of Civil Engineering, Texas A and M University, College Station, TX 77843-3136 (United States)

2008-03-21

Degradative solidification/stabilization with ferrous iron (DS/S-Fe(II)) has been found to be effective in degrading a number of chlorinated aliphatic hydrocarbons including 1,1,1-trichloroethane (1,1,1-TCA), 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA), tetrachloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), vinyl chloride (VC), carbon tetrachloride (CT) and chloroform (CF). Previous studies have characterized degradation kinetics in DS/S-Fe(II) systems as affected by Fe(II) dose, pH and initial target organic concentration. The goal of this study is to investigate the importance of various chemical properties on degradation kinetics of DS/S-Fe(II). This was accomplished by first measuring rate constants for degradation of 1,1,1-TCA, 1,1,2,2-TeCA and 1,2-dichloroethane (1,2-DCA) in individual batch experiments. Rate constants developed in these experiments and those obtained from the literature were related to thermodynamic parameters including one-electron reduction potential, two-electron reduction potential, bond dissociation energy and lowest unoccupied molecular orbital energies. Degradation kinetics by Fe(II) in cement slurries were generally represented by a pseudo-first-order rate law. The results showed that the rate constants for chlorinated methanes (e.g. CT, CF) and chlorinated ethanes (e.g. 1,1,1-TCA) were higher than those for chlorinated ethylenes (e.g. PCE, TCE, 1,1-DCE and VC) under similar experimental conditions. The log of the pseudo-first-order rate constant (k) was found to correlate better with lowest unoccupied molecular orbital energies (E{sub LUMO}) (R{sup 2} = 0.874) than with other thermodynamic parameter descriptors.

Chlorine trifluoride (1963)

International Nuclear Information System (INIS)

Vincent, L.M.; Gillardeau, J.

1963-01-01

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

Chlorine solar neutrino experiment

International Nuclear Information System (INIS)

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

1984-01-01

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

Biofilm formation and sporulation by Bacillus cereus on a stainless steel surface and subsequent resistance of vegetative cells and spores to chlorine, chlorine dioxide, and a peroxyacetic acid-based sanitizer.

Science.gov (United States)

Ryu, Jee-Hoon; Beuchat, Larry R

2005-12-01

Biofilm formation by Bacillus cereus 038-2 on stainless steel coupons, sporulation in the biofilm as affected by nutrient availability, temperature, and relative humidity, and the resistance of vegetative cells and spores in biofilm to sanitizers were investigated. Total counts in biofilm formed on coupons immersed in tryptic soy broth (TSB) at 12 and 22 degrees C consisted of 99.94% of vegetative cells and 0.06% of spores. Coupons on which biofilm had formed were immersed in TSB or exposed to air with 100, 97, 93, or 85% relative humidity. Biofilm on coupons immersed in TSB at 12 degrees C for an additional 6 days or 22 degrees C for an additional 4 days contained 0.30 and 0.02% of spores, respectively, whereas biofilm exposed to air with 100 or 97% relative humidity at 22 degrees C for 4 days contained 10 and 2.5% of spores, respectively. Sporulation did not occur in biofilm exposed to 93 or 85% relative humidity at 22 degrees C. Treatment of biofilm on coupons that had been immersed in TSB at 22 degrees C with chlorine (50 microg/ml), chlorine dioxide (50 microg/ml), and a peroxyacetic acid-based sanitizer (Tsunami 200, 40 microg/ml) for 5 min reduced total cell counts (vegetative cells plus spores) by 4.7, 3.0, and 3.8 log CFU per coupon, respectively; total cell counts in biofilm exposed to air with 100% relative humidity were reduced by 1.5, 2.4, and 1.1 log CFU per coupon, respectively, reflecting the presence of lower numbers of vegetative cells. Spores that survived treatment with chlorine dioxide had reduced resistance to heat. It is concluded that exposure of biofilm formed by B. cereus exposed to air at high relative humidity (> or =97%) promotes the production of spores. Spores and, to a lesser extent, vegetative cells embedded in biofilm are protected against inactivation by sanitizers. Results provide new insights to developing strategies to achieve more effective sanitation programs to minimize risks associated with B. cereus in biofilm formed on

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.)

Disinfection byproduct formation from chlorination of pure bacterial cells and pipeline biofilms.

Science.gov (United States)

Wang, Jun-Jian; Liu, Xin; Ng, Tsz Wai; Xiao, Jie-Wen; Chow, Alex T; Wong, Po Keung

2013-05-15

Disinfection byproduct (DBP) formation is commonly attributed to the reaction between natural organic matters and disinfectants, yet few have considered the contribution from disinfecting bacterial materials - the essential process of water disinfection. Here, we explored the DBP formation from chlorination and chloramination of Escherichia coli and found that most selected DBPs were detectable, including trihalomethanes, haloacetonitriles, chloral hydrate, chloropicrin, and 1,1,1-trichloro-2-propanone. A positive correlation (P = 0.08-0.09) between DBP formation and the log reduction of E. coli implied that breaking down of bacterial cells released precursors for DBP formation. As Pseudomonas aeruginosa is a dominant bacterial species in pipeline biofilms, the DBP formation potentials (DBPFPs) from its planktonic cells and biofilms were characterized. Planktonic cells formed 7-11 times greater trihalomethanes per carbon of those from biofilms but significantly lower (P biofilms on polyvinyl chloride compared to that on galvanized zinc. This study revealed both the in situ disinfection of bacterial planktonic cells in source water and ex situ reaction between biofilms and residual chlorine in pipeline networks as hitherto unknown DBP sources in drinking water. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chlorine

Science.gov (United States)

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

Toxic effects of chlorinated cake flour in rats.

Science.gov (United States)

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

1977-05-01

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

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

Science.gov (United States)

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

2010-03-01

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

Zirconia concentrate chlorination

International Nuclear Information System (INIS)

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

1990-01-01

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

Stratospheric chlorine: Blaming it on nature

International Nuclear Information System (INIS)

Taube, G.

1993-01-01

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

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

Science.gov (United States)

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

2018-01-01

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

Determination of chlorine in nuclear-grade uranium compounds

International Nuclear Information System (INIS)

Yang Chunqing; Liu Fuyun; Huang Dianfan

1988-01-01

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

Radiation-Initiated Chlorination of 1, 2-Dichloroethane

Energy Technology Data Exchange (ETDEWEB)

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

1969-12-15

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

Relation between chlorine with the quality of crude water

International Nuclear Information System (INIS)

Lim, Fang Yee; Mohd Pauzi Abdullah

2008-01-01

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

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

Science.gov (United States)

Hutches, Katherine; Lord, James

2012-07-01

This paper investigates the reaction between pool chlorinators and gasoline. In particular, the propensity for self-ignition and the resulting chemical products were studied. An organic pool chlorinator was combined with gasoline in varying proportions in an attempt to form a hypergolic mixture. None of the combinations resulted in self-ignition, but larger quantities of chlorinator produced vigorous light-colored smoke and a solid mass containing isocyanuric acid and copper chloride. Additionally, the chlorinating abilities of different commercially available pool chlorinators were explored. When Ca(ClO)(2) and sodium dichloro-s-triazinetrione-based chlorinators were used, the presence of gasoline was still visible after 10 days, despite limited chlorination. The trichloro-s-triazinetrione-based chlorinator, however, caused efficient chlorination of the C(2)- and C(3)-alkylbenzenes, making gasoline no longer identifiable. 2012 American Academy of Forensic Sciences. Published 2012. This article is a U.S. Government work and is in the public domain in the U.S.A.

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.

21 CFR 177.2430 - Polyether resins, chlorinated.

Science.gov (United States)

2010-04-01

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

Chlorine transportation risk assessment

International Nuclear Information System (INIS)

Lautkaski, Risto; Mankamo, Tuomas.

1977-02-01

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

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

Directory of Open Access Journals (Sweden)

Costa V.E.U.

1999-01-01

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

LogScope

Science.gov (United States)

Havelund, Klaus; Smith, Margaret H.; Barringer, Howard; Groce, Alex

2012-01-01

LogScope is a software package for analyzing log files. The intended use is for offline post-processing of such logs, after the execution of the system under test. LogScope can, however, in principle, also be used to monitor systems online during their execution. Logs are checked against requirements formulated as monitors expressed in a rule-based specification language. This language has similarities to a state machine language, but is more expressive, for example, in its handling of data parameters. The specification language is user friendly, simple, and yet expressive enough for many practical scenarios. The LogScope software was initially developed to specifically assist in testing JPL s Mars Science Laboratory (MSL) flight software, but it is very generic in nature and can be applied to any application that produces some form of logging information (which almost any software does).

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

Science.gov (United States)

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

2017-06-01

The inactivation of Tubifex tubifex is important to prevent contamination of drinking water. Chlorine is a widely-used disinfectant and the key factor in the inactivation of T. tubifex. This study investigated the inactivation kinetics of chlorine on T. tubifex and the synergistic effect of the sequential use of chlorine and UV irradiation. The experimental results indicated that the Ct (concentration × time reaction ) concept could be used to evaluate the inactivation kinetics of T. tubifex with chlorine, thus allowing for the use of a simpler Ct approach for the assessment of T. tubifex chlorine inactivation requirements. The inactivation kinetics of T. tubifex by chlorine was found to be well-fitted to a delayed pseudo first-order Chick-Watson expression. Sequential experiments revealed that UV irradiation and chlorine worked synergistically to effectively inactivate T. tubifex as a result of the decreased activation energy, E a , induced by primary UV irradiation. Furthermore, the inactivation effectiveness of T. tubifex by chlorine was found to be affected by several drinking water quality parameters including pH, turbidity, and chemical oxygen demand with potassium permanganate (COD Mn ) concentration. High pH exhibited pronounced inactivation effectiveness and the decrease in turbidity and COD Mn concentrations contributed to the inactivation of T. tubifex. Copyright © 2017 Elsevier Ltd. All rights reserved.

Process for producing chlorinated polyethylene

International Nuclear Information System (INIS)

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

1970-01-01

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

Features of copper etching in chlorine-argon plasma

International Nuclear Information System (INIS)

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

1995-01-01

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

Inactivation efficiency of plasmid-encoded antibiotic resistance genes during water treatment with chlorine, UV, and UV/H2O2.

Science.gov (United States)

Yoon, Younggun; Chung, Hay Jung; Wen Di, Doris Yoong; Dodd, Michael C; Hur, Hor-Gil; Lee, Yunho

2017-10-15

This study assessed the inactivation efficiency of plasmid-encoded antibiotic resistance genes (ARGs) both in extracellular form (e-ARG) and present within Escherichia coli (intracellular form, i-ARG) during water treatment with chlorine, UV (254 nm), and UV/H 2 O 2 . A quantitative real-time PCR (qPCR) method was used to quantify the ARG damage to amp R (850 bp) and kan R (806 bp) amplicons, both of which are located in the pUC4K plasmid. The plate count and flow cytometry methods were also used to determine the bacterial inactivation parameters, such as culturability and membrane damage, respectively. In the first part of the study, the kinetics of E. coli inactivation and ARG damage were determined in phosphate buffered solutions. The ARG damage occurred much more slowly than E. coli inactivation in all cases. To achieve 4-log reduction of ARG concentration at pH 7, the required chlorine exposure and UV fluence were 33-72 (mg × min)/L for chlorine and 50-130 mJ/cm 2 for UV and UV/H 2 O 2 . After increasing pH from 7 to 8, the rates of ARG damage decreased for chlorine, while they did not vary for UV and UV/H 2 O 2 . The i-ARGs mostly showed lower rates of damage compared to the e-ARGs due to the protective roles of cellular components against oxidants and UV. The contribution of OH radicals to i-ARG damage was negligible in UV/H 2 O 2 due to significant OH radical scavenging by cellular components. In all cases, the ARG damage rates were similar for amp R versus kan R , except for the chlorination of e-ARGs, in which the damage to amp R occurred faster than that to kan R . Chlorine and UV dose-dependent ARG inactivation levels determined in a wastewater effluent matrix could be reasonably explained by the kinetic data obtained from the phosphate buffered solutions and the expected oxidant (chlorine and OH radicals) demands by water matrix components. These results can be useful in optimizing chlorine and UV-based disinfection systems to achieve ARG

Efficacy of chlorine dioxide against Listeria monocytogenes in brine chilling solutions.

Science.gov (United States)

Valderrama, W B; Mills, E W; Cutter, C N

2009-11-01

Chilled brine solutions are used by the food industry to rapidly cool ready-to-eat meat products after cooking and before packaging. Chlorine dioxide (ClO(2)) was investigated as an antimicrobial additive to eliminate Listeria monocytogenes. Several experiments were performed using brine solutions made of sodium chloride (NaCl) and calcium chloride (CaCl(2)) inoculated with L. monocytogenes and/or treated with 3 ppm of ClO(2). First, 10 and 20% CaCl(2) and NaCl solutions (pH 7.0) were inoculated with a five-strain cocktail of L. monocytogenes to obtain approximately 7 log CFU/ml and incubated 8 h at 0 degrees C. The results demonstrated that L. monocytogenes survived in 10% CaCl(2), 10 and 20% NaCl, and pure water. L. monocytogenes levels were reduced approximately 1.2 log CFU/ml in 20% CaCl(2). Second, inoculated ( approximately 7 log CFU/ml) brine solutions (10 and 20% NaCl and 10% CaCl(2)) treated with 3 ppm of ClO(2) resulted in a approximately 4-log reduction of the pathogen within 90 s. The same was not observed in a solution of 20% CaCl(2); further investigation demonstrated that high levels of divalent cations interfere with the disinfectant. Spent brine solutions from hot dog and ham chilling were treated with ClO(2) at concentrations of 3 or 30 ppm. At these concentrations, ClO(2) did not reduce L. monocytogenes. Removal of divalent cations and organic material in brine solutions prior to disinfection with ClO(2) should be investigated to improve the efficacy of the compound against L. monocytogenes. The information from this study may be useful to processing establishments and researchers who are investigating antimicrobials in chilling brine solutions.

Dynamic Planar Convex Hull with Optimal Query Time and O(log n · log log n ) Update Time

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Jakob, Riko

2000-01-01

The dynamic maintenance of the convex hull of a set of points in the plane is one of the most important problems in computational geometry. We present a data structure supporting point insertions in amortized O(log n · log log log n) time, point deletions in amortized O(log n · log log n) time......, and various queries about the convex hull in optimal O(log n) worst-case time. The data structure requires O(n) space. Applications of the new dynamic convex hull data structure are improved deterministic algorithms for the k-level problem and the red-blue segment intersection problem where all red and all...

Chlorine poisoning

Science.gov (United States)

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

Dispersion of chlorine at seven southern California coastal generating stations

International Nuclear Information System (INIS)

Grove, R.S.

1983-01-01

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

Chlorination leaching of cadmium

International Nuclear Information System (INIS)

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

1978-01-01

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

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

International Nuclear Information System (INIS)

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

2003-01-01

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

Potential biodefense model applications for portable chlorine dioxide gas production.

Science.gov (United States)

Stubblefield, Jeannie M; Newsome, Anthony L

2015-01-01

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

Radiolytic removal of trihalomethane in chlorinated seawater

International Nuclear Information System (INIS)

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

2015-01-01

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

Inactivation of viruses in municipal effluent by chlorine.

OpenAIRE

Hajenian, H. G.; Butler, M.

1980-01-01

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

Heat-Activated Persulfate Oxidation of Chlorinated Solvents in Sandy Soil

Directory of Open Access Journals (Sweden)

Jialu Liu

2014-01-01

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

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

Science.gov (United States)

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

2016-01-15

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

Hardwood log grades and lumber grade yields for factory lumber logs

Science.gov (United States)

Leland F. Hanks; Glenn L. Gammon; Robert L. Brisbin; Everette D. Rast

1980-01-01

The USDA Forest Service Standard Grades for Hardwood Factory Lumber Logs are described, and lumber grade yields for 16 species and 2 species groups are presented by log grade and log diameter. The grades enable foresters, log buyers, and log sellers to select and grade those log suitable for conversion into standard factory grade lumber. By using the apropriate lumber...

Study for the chlorination of zirconium oxide

International Nuclear Information System (INIS)

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

1990-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-11-15

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Chlorine diffusion in uranium dioxide under heavy ion irradiation

International Nuclear Information System (INIS)

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

2007-01-01

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

Chlorine diffusion in uranium dioxide under heavy ion irradiation

Science.gov (United States)

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

2007-04-01

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

Logging Concessions Enable Illegal Logging Crisis in the Peruvian Amazon

OpenAIRE

Finer, Matt; Jenkins, Clinton N.; Sky, Melissa A. Blue; Pine, Justin

2014-01-01

The Peruvian Amazon is an important arena in global efforts to promote sustainable logging in the tropics. Despite recent efforts to achieve sustainability, such as provisions in the US?Peru Trade Promotion Agreement, illegal logging continues to plague the region. We present evidence that Peru's legal logging concession system is enabling the widespread illegal logging via the regulatory documents designed to ensure sustainable logging. Analyzing official government data, we found that 68.3%...

Automatic analyzing device for chlorine ion

International Nuclear Information System (INIS)

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

1997-01-01

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

Kinetic modelling of chlorination of nitrided ilmenite using MATLAB

Energy Technology Data Exchange (ETDEWEB)

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

2016-07-19

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

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.

http Log Analysis

DEFF Research Database (Denmark)

Bøving, Kristian Billeskov; Simonsen, Jesper

2004-01-01

This article documents how log analysis can inform qualitative studies concerning the usage of web-based information systems (WIS). No prior research has used http log files as data to study collaboration between multiple users in organisational settings. We investigate how to perform http log...... analysis; what http log analysis says about the nature of collaborative WIS use; and how results from http log analysis may support other data collection methods such as surveys, interviews, and observation. The analysis of log files initially lends itself to research designs, which serve to test...... hypotheses using a quantitative methodology. We show that http log analysis can also be valuable in qualitative research such as case studies. The results from http log analysis can be triangulated with other data sources and for example serve as a means of supporting the interpretation of interview data...

Determination of carbon chlorine and fluorine in uranium dioxide

International Nuclear Information System (INIS)

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

1983-01-01

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

Synthesis and spectral properties of novel chlorinated pH fluorescent probes

International Nuclear Information System (INIS)

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

2011-01-01

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

Evaluation of gaseous chlorine dioxide for the inactivation of Tulane virus on blueberries.

Science.gov (United States)

Kingsley, David H; Pérez-Pérez, Rafael E; Niemira, Brendan A; Fan, Xuetong

2018-05-20

To determine the effectiveness of gaseous chlorine dioxide (gClO 2 ) against a human norovirus surrogate on produce, gClO 2 was generated and applied to Tulane virus-coated blueberries in a 240 ml-treatment chamber. gClO 2 was produced by an acidifying sodium chlorite solution. Initial assessments indicated that blueberries treated with gClO 2 generated from ≤1 mg acidified sodium chlorite in the small chamber appeared unaffected while gClO 2 generated from ≥10 mg of acidified sodium chlorite solution altered the appearance and quality of the blueberries. Treatments of inoculated blueberries with gClO 2 generated from 0.1 mg sodium chlorite reduced the virus populations by >1 log after exposure for 30 to 330 min. For the 1 mg sodium chlorite treatments, the virus populations were reduced by >2.2 log after 15 min exposure and to non-detectable levels (>3.3 logs reductions) after 180 min exposure. Measured concentrations of gClO 2 peaked in the treatment chamber at 0.9 μg/l after 10 min for 0.1 mg treatments and 600 μg/l after around 20 min for 1 mg treatment. Overall results indicate that gClO 2 could be a feasible waterless intervention for blueberries and other produce. Published by Elsevier B.V.

Log quality enhancement: A systematic assessment of logging company wellsite performance and log quality

International Nuclear Information System (INIS)

Farnan, R.A.; Mc Hattie, C.M.

1984-01-01

To improve the monitoring of logging company performance, computer programs were developed to assess information en masse from log quality check lists completed on wellsite by the service company engineer and Phillips representative. A study of all logging jobs performed by different service companies for Phillips in Oklahoma (panhandle excepted) during 1982 enabled several pertinent and beneficial interpretations to be made. Company A provided the best tool and crew service. Company B incurred an excessive amount of lost time related to tool failure, in particular the neutron-density tool combination. Company C, although used only three times, incurred no lost time. With a reasonable data base valid conclusions were made pertaining, for example, to repeated tool malfunctions. The actual logs were then assessed for quality

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

Science.gov (United States)

Zheng, Muzi; He, Chunguang; He, Qiang

2015-12-01

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

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....

Handwashing and Ebola virus disease outbreaks: A randomized comparison of soap, hand sanitizer, and 0.05% chlorine solutions on the inactivation and removal of model organisms Phi6 and E. coli from hands and persistence in rinse water.

Science.gov (United States)

Wolfe, Marlene K; Gallandat, Karin; Daniels, Kyle; Desmarais, Anne Marie; Scheinman, Pamela; Lantagne, Daniele

2017-01-01

To prevent Ebola transmission, frequent handwashing is recommended in Ebola Treatment Units and communities. However, little is known about which handwashing protocol is most efficacious. We evaluated six handwashing protocols (soap and water, alcohol-based hand sanitizer (ABHS), and 0.05% sodium dichloroisocyanurate, high-test hypochlorite, and stabilized and non-stabilized sodium hypochlorite solutions) for 1) efficacy of handwashing on the removal and inactivation of non-pathogenic model organisms and, 2) persistence of organisms in rinse water. Model organisms E. coli and bacteriophage Phi6 were used to evaluate handwashing with and without organic load added to simulate bodily fluids. Hands were inoculated with test organisms, washed, and rinsed using a glove juice method to retrieve remaining organisms. Impact was estimated by comparing the log reduction in organisms after handwashing to the log reduction without handwashing. Rinse water was collected to test for persistence of organisms. Handwashing resulted in a 1.94-3.01 log reduction in E. coli concentration without, and 2.18-3.34 with, soil load; and a 2.44-3.06 log reduction in Phi6 without, and 2.71-3.69 with, soil load. HTH performed most consistently well, with significantly greater log reductions than other handwashing protocols in three models. However, the magnitude of handwashing efficacy differences was small, suggesting protocols are similarly efficacious. Rinse water demonstrated a 0.28-4.77 log reduction in remaining E. coli without, and 0.21-4.49 with, soil load and a 1.26-2.02 log reduction in Phi6 without, and 1.30-2.20 with, soil load. Chlorine resulted in significantly less persistence of E. coli in both conditions and Phi6 without soil load in rinse water (phand hygiene in Ebola contexts, considering the potential benefit of chlorine-based methods in rinse water persistence.

Chlorine isotopes potential as geo-chemical tracers

Digital Repository Service at National Institute of Oceanography (India)

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

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

Chlorinated drinking water for lightweight laying hens

Directory of Open Access Journals (Sweden)

A.F. Schneider

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

Quantifying Short-Chain Chlorinated Paraffin Congener Groups.

Science.gov (United States)

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

2017-09-19

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

Log N-log S in inconclusive

Science.gov (United States)

Klebesadel, R. W.; Fenimore, E. E.; Laros, J.

1983-01-01

The log N-log S data acquired by the Pioneer Venus Orbiter Gamma Burst Detector (PVO) are presented and compared to similar data from the Soviet KONUS experiment. Although the PVO data are consistent with and suggestive of a -3/2 power law distribution, the results are not adequate at this state of observations to differentiate between a -3/2 and a -1 power law slope.

Tolerance of anaerobic bacteria to chlorinated solvents.

Science.gov (United States)

Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

2014-01-01

The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

Encyclopedia of well logging

International Nuclear Information System (INIS)

Desbrandes, R.

1985-01-01

The 16 chapters of this book aim to provide students, trainees and engineers with a manual covering all well-logging measurements ranging from drilling to productions, from oil to minerals going by way of geothermal energy. Each chapter is a summary but a bibliography is given at the end of each chapter. Well-logging during drilling, wireline logging equipment and techniques, petroleum logging, data processing of borehole data, interpretation of well-logging, sampling tools, completion and production logging, logging in relief wells to kill off uncontrolled blowouts, techniques for high temperature geothermal energy, small-scale mining and hydrology, logging with oil-base mud and finally recommended logging programs are all topics covered. There is one chapter on nuclear well-logging which is indexed separately. (UK)

Interpretation of horizontal well production logs: influence of logging tool

Energy Technology Data Exchange (ETDEWEB)

Ozkan, E. [Colorado School of Mines, Boulder, CO (United States); Sarica, C. [Pennsylvania State Univ., College Park, PA (United States); Haci, M. [Drilling Measurements, Inc (United States)

1998-12-31

The influence of a production-logging tool on wellbore flow rate and pressure measurements was investigated, focusing on the disturbence caused by the production-logging tool and the coiled tubing on the original flow conditions in the wellbore. The investigation was carried out using an analytical model and single-phase liquid flow was assumed. Results showed that the production-logging tool influenced the measurements as shown by the deviation of the original flow-rate, pressure profiles and low-conductivity wellbores. High production rates increase the effect of the production-logging tool. Recovering or inferring the original flow conditions in the wellbore from the production-logging data is a very complex process which cannot be solved easily. For this reason, the conditions under which the information obtained by production-logging is meaningful is of considerable practical interest. 7 refs., 2 tabs., 15 figs.

Release of chlorine from biomass at gasification conditions

Energy Technology Data Exchange (ETDEWEB)

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

1997-05-01

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

Release of chlorine from biomass at gasification conditions

International Nuclear Information System (INIS)

Bjoerkman, E.; Stroemberg, B.

1997-05-01

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

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

Science.gov (United States)

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

2017-11-01

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

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

KAUST Repository

Peters, Marjolein C. F. M.

2017-12-22

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

A study on chlorination of uranium metal using ammonium chloride

International Nuclear Information System (INIS)

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

2017-01-01

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

Preliminary GRS Measurement of Chlorine Distribution on Surface of Mars

Science.gov (United States)

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

2003-12-01

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

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...

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

African Journals Online (AJOL)

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

The Synthesis of Carbon Nanomaterials using Chlorinated ...

African Journals Online (AJOL)

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

Does Chlorination of Seawater Reverse Osmosis Membranes Control Biofouling?

KAUST Repository

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

2015-01-01

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

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.

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...

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)

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.

Susceptibility of Legionella pneumophila to chlorine in tap water.

Science.gov (United States)

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

1983-11-01

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

Analysis of RIA standard curve by log-logistic and cubic log-logit models

International Nuclear Information System (INIS)

Yamada, Hideo; Kuroda, Akira; Yatabe, Tami; Inaba, Taeko; Chiba, Kazuo

1981-01-01

In order to improve goodness-of-fit in RIA standard analysis, programs for computing log-logistic and cubic log-logit were written in BASIC using personal computer P-6060 (Olivetti). Iterative least square method of Taylor series was applied for non-linear estimation of logistic and log-logistic. Hear ''log-logistic'' represents Y = (a - d)/(1 + (log(X)/c)sup(b)) + d As weights either 1, 1/var(Y) or 1/σ 2 were used in logistic or log-logistic and either Y 2 (1 - Y) 2 , Y 2 (1 - Y) 2 /var(Y), or Y 2 (1 - Y) 2 /σ 2 were used in quadratic or cubic log-logit. The term var(Y) represents squares of pure error and σ 2 represents estimated variance calculated using a following equation log(σ 2 + 1) = log(A) + J log(y). As indicators for goodness-of-fit, MSL/S sub(e)sup(2), CMD% and WRV (see text) were used. Better regression was obtained in case of alpha-fetoprotein by log-logistic than by logistic. Cortisol standard curve was much better fitted with cubic log-logit than quadratic log-logit. Predicted precision of AFP standard curve was below 5% in log-logistic in stead of 8% in logistic analysis. Predicted precision obtained using cubic log-logit was about five times lower than that with quadratic log-logit. Importance of selecting good models in RIA data processing was stressed in conjunction with intrinsic precision of radioimmunoassay system indicated by predicted precision. (author)

Selective recovery of uranium from Ca-Mg uranates by chlorination

International Nuclear Information System (INIS)

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

2017-01-01

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

Earth formation porosity log using measurement of neutron energy spectrum

International Nuclear Information System (INIS)

1981-01-01

Methods and apparatus are described for measuring the porosity of subsurface earth formations in the vicinity of a well borehole by means of neutron well logging techniques. All the commercial techniques for measuring porosity currently available are not as accurate as desirable due to variations in the borehole wall diameter, in the borehole fluids (e.g. with chlorine content) in the casings of the borehole etc. This invention seeks to improve accuracy by using a measurement of the epithermal neutron population at one detector and the fast neutron population at a second detector, spaced approximately the same distance from a neutron source. The latter can be detected either by a fast neutron detector or indirectly by an inelastic gamma ray detector. Background correction can be made, and special detectors used, to discriminate against the detection of thermal neutrons or their resultant capture gamma rays. These fluctuations affect the measurement of thermal neutron populations. (U.K.)

Selective recovery of uranium from Ca-Mg uranates by chlorination

Science.gov (United States)

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

2017-07-01

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

Detection of chlorinated aromatic compounds

Science.gov (United States)

Ekechukwu, A.A.

1996-02-06

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

Chlorinated rubbers with advanced properties for tire industry

Science.gov (United States)

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

2017-12-01

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

Decomposition of dilute residual active chlorine in sea-water

International Nuclear Information System (INIS)

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

1985-01-01

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

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

Science.gov (United States)

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

2018-06-15

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

Antiradiation effectiveness of the chlorine C

International Nuclear Information System (INIS)

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

1996-01-01

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

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

Digital Repository Service at National Institute of Oceanography (India)

Patil, J.S.; Jagadeesan, V.

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

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

International Nuclear Information System (INIS)

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

2000-01-01

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

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

International Nuclear Information System (INIS)

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

1995-01-01

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

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

Science.gov (United States)

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

2017-04-04

We report the identification of N-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N,N-di-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, 35 Cl/ 37 Cl isotopic patterns, and MS/MS spectra. These identified N-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except N,N-di-Cl-Phe-Gly. To enable sensitive detection of N-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with multiple reaction monitoring (MRM) mode. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the N-chlorinated dipeptides were at background levels. These results suggest that the N-chlorinated dipeptides are produced by chlorination. This study has identified N-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water.

Selective recovery of uranium from Ca-Mg uranates by chlorination

Energy Technology Data Exchange (ETDEWEB)

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

2017-07-15

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

Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

Energy Technology Data Exchange (ETDEWEB)

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

2016-02-13

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

Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination

International Nuclear Information System (INIS)

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

2016-01-01

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

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.

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

International Nuclear Information System (INIS)

Mattila, H.

1991-01-01

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

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

Science.gov (United States)

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

2005-09-01

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

Chlorination of organophosphorus pesticides in natural waters

Energy Technology Data Exchange (ETDEWEB)

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

2008-05-01

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

Chlorination of organophosphorus pesticides in natural waters

International Nuclear Information System (INIS)

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

2008-01-01

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

Regiospecific synthesis of polychlorinated dibenzofurans with chlorine-37 excess

International Nuclear Information System (INIS)

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

1991-01-01

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

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...

Monitoring chlorination practices during operation at TAPS

International Nuclear Information System (INIS)

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

1995-01-01

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

Superior bactericidal activity of N-bromine compounds compared to their N-chlorine analogues can be reversed under protein load.

Science.gov (United States)

Gottardi, W; Klotz, S; Nagl, M

2014-06-01

To investigate and compare the bactericidal activity (BA) of active bromine and chlorine compounds in the absence and presence of protein load. Quantitative killing tests against Escherichia coli and Staphylococcus aureus were performed both in the absence and in the presence of peptone with pairs of isosteric active chlorine and bromine compounds: hypochlorous and hypobromous acid (HOCl and HOBr), dichloro- and dibromoisocyanuric acid, chlorantine and bromantine (1,3-dibromo- and 1,3 dichloro-5,5-dimethylhydantoine), chloramine T and bromamine T (N-chloro- and N-bromo-4-methylbenzenesulphonamide sodium), and N-chloro- and N-bromotaurine sodium. To classify the bactericidal activities on a quantitative basis, an empirical coefficient named specific bactericidal activity (SBA), founded on the parameters of killing curves, was defined: SBA= mean log reductions/(mean exposure times x concentration) [mmol 1(-1) min (-1)]. In the absence of peptone, tests with washed micro-organisms revealed a throughout higher BA of bromine compounds with only slight differences between single substances. This was in contrast to chlorine compounds, whose killing times differed by a factor of more than four decimal powers. As a consequence, also the isosteric pairs showed according differences. In the presence of peptone, however, bromine compounds showed an increased loss of BA, which partly caused a reversal of efficacy within isosteric pairs. In medical practice, weakly oxidizing active chlorine compounds like chloramines have the highest potential as topical anti-infectives in the presence of proteinaceous material (mucous membranes, open wounds). Active bromine compounds, on the other hand, have their chance at insensitive body regions with low organic matter, for example skin surfaces. The expected protein load is one of the most important parameters for selection of a suited active halogen compound. © 2014 The Society for Applied Microbiology.

Generalized localization for the double trigonometric Fourier series and the Walsh-Fourier series of functions in L log +L log + log +L

International Nuclear Information System (INIS)

Bloshanskaya, S K; Bloshanskii, I L; Roslova, T Y

1998-01-01

For an arbitrary open set Ω subset of I 2 =[0,1) 2 and an arbitrary function f element of L log + L log + log + L(I 2 ) such that f=0 on Ω the double Fourier series of f with respect to the trigonometric system Ψ=E and the Walsh-Paley system Ψ=W is shown to converge to zero (over rectangles) almost everywhere on Ω. Thus, it is proved that generalized localization almost everywhere holds on arbitrary open subsets of the square I 2 for the double trigonometric Fourier series and the Walsh-Fourier series of functions in the class L log + L log + log + L (in the case of summation over rectangles). It is also established that such localization breaks down on arbitrary sets that are not dense in I 2 , in the classes Φ Ψ (L)(I 2 ) for the orthonormal system Ψ=E and an arbitrary function such that Φ E (u)=o(u log + log + u) as u→∞ or for Φ W (u)=u( log + log + u) 1-ε , 0<ε<1

Experimental cancer studies of chlorinated by-products

International Nuclear Information System (INIS)

Komulainen, Hannu

2004-01-01

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

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

International Nuclear Information System (INIS)

Osswald, Aurelie

2016-01-01

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

Effects of short-chain chlorinated paraffins on soil organisms.

Science.gov (United States)

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

2007-06-01

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

Nonaqueous chlorination of uranium metal in tributyl phosphate

International Nuclear Information System (INIS)

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

2005-01-01

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

Hydrochloric acid recycling from chlorinated hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

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

1994-12-31

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

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.

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

International Nuclear Information System (INIS)

Seo, E.S.M.

1983-01-01

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

Borehole logging

International Nuclear Information System (INIS)

Olsen, H.

1995-01-01

Numerous ground water investigations have been accomplished by means of borehole logging. Borehole logging can be applied to establish new water recovery wells, to control the existing water producing wells and source areas and to estimate ground water quality. (EG)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Effects of aging on chlorinated plasma polymers

Energy Technology Data Exchange (ETDEWEB)

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

2017-07-15

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

Application of Highly Purified Electrolyzed Chlorine Dioxide for Tilapia Fillet Disinfection

Directory of Open Access Journals (Sweden)

Chen-Hsing Yu

2014-01-01

Full Text Available This research aimed to develop an electrolysis method to generate high-concentration chlorine dioxide (ClO2 for tilapia fillet disinfection. The designed generator produced up to 3500 ppm of ClO2 at up to 99% purity. Tilapia fillets were soaked in a 400 ppm ClO2 solution for 5, 10, and 25 min. Results show that total plate counts of tilapia, respectively, decreased by 5.72 to 3.23, 2.10, and 1.09 log CFU/g. In addition, a 200 ppm ClO2 solution eliminated coliform bacteria and Escherichia coli in 5 min with shaking treatment. Furthermore, ClO2 and trihalomethanes (THMs residuals on tilapia fillets were analyzed by GC/MS and were nondetectable (GC-MS detection limit was 0.12 ppb. The results conform to Taiwan’s environmental protection regulations and act governing food sanitation.

Blends of caprolactam/caprolactone copolymers and chlorinated polymers

NARCIS (Netherlands)

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

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1977-07-01

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

Logging Concessions Enable Illegal Logging Crisis in the Peruvian Amazon

Science.gov (United States)

Finer, Matt; Jenkins, Clinton N.; Sky, Melissa A. Blue; Pine, Justin

2014-04-01

The Peruvian Amazon is an important arena in global efforts to promote sustainable logging in the tropics. Despite recent efforts to achieve sustainability, such as provisions in the US-Peru Trade Promotion Agreement, illegal logging continues to plague the region. We present evidence that Peru's legal logging concession system is enabling the widespread illegal logging via the regulatory documents designed to ensure sustainable logging. Analyzing official government data, we found that 68.3% of all concessions supervised by authorities were suspected of major violations. Of the 609 total concessions, nearly 30% have been cancelled for violations and we expect this percentage to increase as investigations continue. Moreover, the nature of the violations indicate that the permits associated with legal concessions are used to harvest trees in unauthorized areas, thus threatening all forested areas. Many of the violations pertain to the illegal extraction of CITES-listed timber species outside authorized areas. These findings highlight the need for additional reforms.

Logging concessions enable illegal logging crisis in the Peruvian Amazon.

Science.gov (United States)

Finer, Matt; Jenkins, Clinton N; Sky, Melissa A Blue; Pine, Justin

2014-04-17

The Peruvian Amazon is an important arena in global efforts to promote sustainable logging in the tropics. Despite recent efforts to achieve sustainability, such as provisions in the US-Peru Trade Promotion Agreement, illegal logging continues to plague the region. We present evidence that Peru's legal logging concession system is enabling the widespread illegal logging via the regulatory documents designed to ensure sustainable logging. Analyzing official government data, we found that 68.3% of all concessions supervised by authorities were suspected of major violations. Of the 609 total concessions, nearly 30% have been cancelled for violations and we expect this percentage to increase as investigations continue. Moreover, the nature of the violations indicate that the permits associated with legal concessions are used to harvest trees in unauthorized areas, thus threatening all forested areas. Many of the violations pertain to the illegal extraction of CITES-listed timber species outside authorized areas. These findings highlight the need for additional reforms.

Direct Chlorination of Zircon Sand

International Nuclear Information System (INIS)

Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

2002-01-01

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

Method and apparatus for neutron induced gamma ray logging for lithology identificaion

International Nuclear Information System (INIS)

Oliver, D.W.; Culver, R.B.

1979-01-01

A pulsed neutron generator in a well logging instrument is pulsed at a clock frequency of 20 KHz. Inelastic scatter gamma rays are detected during a first time interval coinciding with the neutron source being on and capture gamma rays are measured during a second interval subsequent to the end of each neutron burst. Only a single detected pulse, assuming detection occurs, is transmitted during each of the two detection intervals. Sync pulses are generated in the well logging instrument scaled down to a frequency of 200 Hz for transmission to the earth's surface. At the earth's surface, the scaled-down sync pulses are applied to a phase-locked loop system for regenerating the sync pulses to the same frequency as that of the clock frequency used to pulse the neutron source and to open the detection gates in the borehole instrument. The regenerated sync pulses are used in the surface instrumentation to route the pulses occurring in the inelastic interval into one section of a multichannel analyzer memory and the pulses occurring in the capture interval into another section of the multichannel analyzer. The use of memory address decoders, subtractors and ratio circuits enables both a carbon/oxygen ratio and a silicon/calcium ratio to be struck, substantially independent of the chlorine content of the borehole and formation

Selective synthesis and characterization of chlorins as sensitizers for photodynamic therapy

Science.gov (United States)

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

1996-04-01

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

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

International Nuclear Information System (INIS)

Yang Chunqing; Liu Fuyun; Huang Dianfan.

1989-01-01

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

Dense chlorinated solvents and other DNAPLs in groundwater

DEFF Research Database (Denmark)

Broholm, K.

1996-01-01

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

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

Science.gov (United States)

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

2017-03-22

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

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

Energy Technology Data Exchange (ETDEWEB)

Li Hongna, E-mail: lihongna@gmail.com [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Zhu Xiuping [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China); Ni Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

2011-11-30

Highlights: > Electrochemical, O{sub 3}, NaClO and NH{sub 2}Cl were compared at respective optimal condition. > Disinfection efficacy was similar for different bacteria in electrolysis. > Harsh Bacillus was inactivated more difficult in O{sub 3}, NaClO and NH{sub 2}Cl system. > Efficient disinfection of electrolysis was attributed to nonselectivity of {center_dot}OH. > Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L{sup -1} for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments

Comparison of electrochemical method with ozonation, chlorination and monochloramination in drinking water disinfection

International Nuclear Information System (INIS)

Li Hongna; Zhu Xiuping; Ni Jinren

2011-01-01

Highlights: → Electrochemical, O 3 , NaClO and NH 2 Cl were compared at respective optimal condition. → Disinfection efficacy was similar for different bacteria in electrolysis. → Harsh Bacillus was inactivated more difficult in O 3 , NaClO and NH 2 Cl system. → Efficient disinfection of electrolysis was attributed to nonselectivity of ·OH. → Cell surface damage was more obvious in electrochemical process than the others. - Abstract: Electrochemical process in chloride-free electrolytes was proved to be powerful in disinfection due to the strong oxidants produced in the electrolysis and no formation of disinfection byproducts (DBPs). In this study, disinfection experiments were conducted by electrochemical treatment compared with ordinary and advanced methods (ozonation, chlorination and monochloramination), with Escherichia coli (E. coli) K-12, Staphylococcus aureus (S. aureus) A106, Bacillus subtilis (BST) and an isolated Bacillus as the representative microorganisms. Firstly, factor tests were performed on E. coli to obtain the optimal conditions of the four disinfection procedures. At their respective optimal condition, CT (concentration of disinfectant x contact time) value of a 4-log E. coli inactivation was 33.5, 1440, 1575, 1674 mg min L -1 for electrochemical process, ozonation, chlorination and monochloramination, respectively. It was demonstrated that the disinfection availability was in the following order: electrochemical process > ozonation > chlorination > monochloramination, which could be attributed to the hydroxyl radical generated in the electrolysis, with strong oxidizing ability and non-selectivity compared with the other three disinfectants. Moreover, the disinfection efficacy of the four disinfection procedures was compared for four different bacteria. It was found that the disinfection efficacy was similar for the selected four bacteria in electrochemical process, while in the other three treatments inactivation of the two

Estimates of Gibbs free energies of formation of chlorinated aliphatic compounds

NARCIS (Netherlands)

Dolfing, Jan; Janssen, Dick B.

1994-01-01

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

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

Science.gov (United States)

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

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

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

Science.gov (United States)

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

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

International Nuclear Information System (INIS)

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

2008-01-01

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

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.

Recovery of Actinides from Actinide-Aluminium Alloys: Chlorination Route

Energy Technology Data Exchange (ETDEWEB)

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

2008-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

1994-08-01

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

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

International Nuclear Information System (INIS)

1994-08-01

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

Chlorine inactivation of fungal spores on cereal grains.

Science.gov (United States)

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

1997-04-01

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

Thermodynamic consideration on chlorination of uraniferous phosphorite

International Nuclear Information System (INIS)

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

1989-01-01

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

Factorial analysis of the trihalomethanes formation in water disinfection using chlorine

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1982-01-01

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

Prompt gamma analysis of chlorine in concrete for corrosion study

Energy Technology Data Exchange (ETDEWEB)

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

2006-02-15

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

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

Science.gov (United States)

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

2018-06-01

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

Investigation of molybdenum pentachloride interaction with chlorine

International Nuclear Information System (INIS)

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

1993-01-01

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

Chlorin photosensitizers sterically designed to prevent self-aggregation.

Science.gov (United States)

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

2011-11-04

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

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

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

Science.gov (United States)

Merel, Sylvain; Clément, Michel; Thomas, Olivier

2010-04-01

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

Non-destructive analysis of chlorine in fly ash cement concrete

International Nuclear Information System (INIS)

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

2009-01-01

Preventive measures against reinforcement corrosion in concrete require increasing concrete density to prevent the diffusion of chloride ions to the steel surface. Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to concrete to increase its density. Monitoring the chloride concentration in concrete is required to assess the chances of reinforcement corrosion. In this study, FA was added to Portland cement concrete to increase its density. Prompt gamma neutron activation analysis (PGNAA) technique was utilized to analyze the concentration of chlorine in concrete. The chlorine concentration in the FA cement concrete was evaluated by determining the yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV gamma-rays of chlorine from the FA concrete specimen containing 0.4-3.5 wt% chlorine. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the calculated yield obtained through the Monte Carlo simulations. The Minimum Detectable Concentration (MDC) of chlorine in FA cement concrete was also calculated. The best value of MDC limit of chlorine in the FA cement concrete was found to be 0.022±0.007 and 0.038±0.017 wt% for 1.16 and 6.11 MeV prompt gamma-rays, respectively. Within the statistical uncertainty, the lower bound of MDC meets the maximum permissible limit of 0.03 wt% of chlorine in concrete set by American Concrete Institute Committee 318.

Non-destructive analysis of chlorine in fly ash cement concrete

Energy Technology Data Exchange (ETDEWEB)

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

2009-08-11

Preventive measures against reinforcement corrosion in concrete require increasing concrete density to prevent the diffusion of chloride ions to the steel surface. Pozzolanic materials, such as fly ash (FA), silica fume (SF), and blast furnace slag (BFS) are added to concrete to increase its density. Monitoring the chloride concentration in concrete is required to assess the chances of reinforcement corrosion. In this study, FA was added to Portland cement concrete to increase its density. Prompt gamma neutron activation analysis (PGNAA) technique was utilized to analyze the concentration of chlorine in concrete. The chlorine concentration in the FA cement concrete was evaluated by determining the yield of 1.16, 1.95, 6.11, 6.62, 7.41, 7.79, and 8.58 MeV gamma-rays of chlorine from the FA concrete specimen containing 0.4-3.5 wt% chlorine. An excellent agreement was noted between the experimental yield of the prompt gamma-rays and the calculated yield obtained through the Monte Carlo simulations. The Minimum Detectable Concentration (MDC) of chlorine in FA cement concrete was also calculated. The best value of MDC limit of chlorine in the FA cement concrete was found to be 0.022{+-}0.007 and 0.038{+-}0.017 wt% for 1.16 and 6.11 MeV prompt gamma-rays, respectively. Within the statistical uncertainty, the lower bound of MDC meets the maximum permissible limit of 0.03 wt% of chlorine in concrete set by American Concrete Institute Committee 318.

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.

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

Science.gov (United States)

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

2015-12-01

Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of trihalomethane from chlorinated seawater using gamma radiation.

Science.gov (United States)

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

2015-12-01

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

Determination of chlorine in graphite by combustion-ion chromatography

International Nuclear Information System (INIS)

Chen Lianzhong; Watanabe, Kazuo; Itoh, Mitsuo.

1995-09-01

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

Chlorination of uranium oxides with CCl4 using a mechanochemical method

Science.gov (United States)

Kitawaki, Shinichi; Nagai, Takayuki; Sato, Nobuaki

2013-08-01

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

Chlorinated tyrosine derivatives in insect cuticle

DEFF Research Database (Denmark)

Andersen, Svend Olav

2004-01-01

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

Uptake, turnover and distribution of chlorinated fatty acids in aquatic biota

Energy Technology Data Exchange (ETDEWEB)

Bjoern, Helena

1999-09-01

Chlorinated fatty acids (CIFAs) are the major contributors of extractable, organically bound chlorine in fish lipids. A known anthropogenic source of CIFAs is chlorine bleached pulp production. Additional anthropogenic sources may exist, e.g., chlorine-containing discharge from industrial and household waste and they may also occur naturally. CIFAs have a wide geographic distribution. They have, for instance, been identified in fish both from Alaskan and Scandinavian waters. In toxicological studies of CIFAs, the most pronounced effects have been found in reproductive related processes. CIFAs have also been shown to disrupt cell membrane functions. The present study was carried out to further characterise the ecotoxicological properties of CIFAs and their presence in biota. To investigate the biological stability of CIFAs, two experiments were carried out using radiolabelled chlorinated and non-chlorinated fatty acids. In both experiments, CIFAs were taken up from food by fish and assimilated to lipids. From the first experiment it was concluded that the chlorinated fatty acid investigated was turned over in the fish to a lower degree than the non-chlorinated analogue. In the second experiment, the transfer of a chlorinated fatty acid was followed over several trophic levels and the chlorinated fatty acid was transferred to the highest trophic level. In samples with differing loads of persistent organic pollutants (POPs) from both fish and marine mammals, high concentrations and diversity of CIFAs were detected. This was also observed in samples with low POP concentration. Chlorohydroxy fatty acids made up a considerable portion of the CIFAs in certain samples, both from limnic fish and marine mammals. CIFAs in fish were found to be bound in complex lipids such as triacylglycerols (storage lipids) and phospholipids, as well as in acyl sterols (membrane lipids). In the marine mammals investigated, high concentrations of CIFAs were mainly bound in phospholipids. If

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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.

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

Science.gov (United States)

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

2009-05-15

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

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.

Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

International Nuclear Information System (INIS)

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

1986-01-01

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

Structural and optical properties of chlorinated plasma polymers

Energy Technology Data Exchange (ETDEWEB)

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

2011-12-30

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

Structural and optical properties of chlorinated plasma polymers

International Nuclear Information System (INIS)

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

2011-01-01

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

Study of the reservoirs of Jurassic and Cretaceous periods in the south-cast slope of Central Kara-Kum vault using combination of acoustic logging, neutron-gamma logging, gamma logging, and electrical logging

International Nuclear Information System (INIS)

Meredov, T.M.; Baranov, M.I.

1978-01-01

Considered is the possibility of application of the combination of neutron-gamma logging, gamma logging al partitioncoustic logging and electrical logging to lithologica of sections, discovery reservoir layers in carbonate and terrigeneous sections as well as quantitative estimation of the porosity coefficients values at prospecting areas in the south-east slope of Central Kara-Kum vault. Neutron-gamma logging mostly makes it possible to partition carbonate rocks into limestones, dolomites and their interstitial variaties and to indicate sand stone layers with different degree of carbonate content

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl{sub 3}. A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl{sub 3} alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl{sub 2}/UAl{sub 3} molar ratio, providing complete chlorination of the alloy without formation of volatile UCl{sub 5} and UCl{sub 6}. The results showed high efficient chlorination at a temperature of 150 deg. C.

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

International Nuclear Information System (INIS)

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

2011-01-01

Pyrochemical processes in molten LiCl-KCl are being developed in ITU for recovery of actinides from spent nuclear fuel. The fuel is anodically dissolved to the molten salt electrolyte and actinides are electrochemically reduced on solid aluminium cathodes forming solid actinide-aluminium alloys. A chlorination route is being investigated for recovery of actinides from the alloys. This route consists in three steps: Vacuum distillation for removal of the salt adhered on the electrode, chlorination of the actinide-aluminium alloys by chlorine gas and sublimation of the formed AlCl 3 . A thermochemical study showed thermodynamic feasibility of all three steps. On the basis of the conditions identified by the calculations, experiments using pure UAl 3 alloy were carried out to evaluate and optimise the chlorination step. The work was focused on determination of the optimal temperature and Cl 2 /UAl 3 molar ratio, providing complete chlorination of the alloy without formation of volatile UCl 5 and UCl 6 . The results showed high efficient chlorination at a temperature of 150 deg. C.

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

International Nuclear Information System (INIS)

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

1980-01-01

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

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...

Chlorine gas processing of oxide nuclear fuel particles containing thorium

International Nuclear Information System (INIS)

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

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

The Meaning of Logs

NARCIS (Netherlands)

Etalle, Sandro; Massacci, Fabio; Yautsiukhin, Artsiom

2007-01-01

While logging events is becoming increasingly common in computing, in communication and in collaborative work, log systems need to satisfy increasingly challenging (if not conflicting) requirements.Despite the growing pervasiveness of log systems, to date there is no high-level framework which

The Meaning of Logs

NARCIS (Netherlands)

Etalle, Sandro; Massacci, Fabio; Yautsiukhin, Artsiom; Lambrinoudakis, Costas; Pernul, Günther; Tjoa, A Min

While logging events is becoming increasingly common in computing, in communication and in collaborative environments, log systems need to satisfy increasingly challenging (if not conflicting) requirements. In this paper we propose a high-level framework for modeling log systems, and reasoning about

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.

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.

Bacterial oxidation of low-chlorinated compounds under anoxic conditions

NARCIS (Netherlands)

Dijk, J.A.

2005-01-01

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

Radioimmunoassay for chlorinated dibenzo-p-dioxins

International Nuclear Information System (INIS)

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

1980-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2016-12-13

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

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

Directory of Open Access Journals (Sweden)

Hamzeh Ali Jamali1

2014-06-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

The chlorination kinetics of zirconium dioxide mixed with carbon black

International Nuclear Information System (INIS)

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

2011-01-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

Science.gov (United States)

Mao, Guannan; Wang, Yingying; Hammes, Frederik

2018-02-01

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

Immobilization of chlorine dioxide modified cells for uranium absorption

International Nuclear Information System (INIS)

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

2014-01-01

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

SDSS Log Viewer: visual exploratory analysis of large-volume SQL log data

Science.gov (United States)

Zhang, Jian; Chen, Chaomei; Vogeley, Michael S.; Pan, Danny; Thakar, Ani; Raddick, Jordan

2012-01-01

User-generated Structured Query Language (SQL) queries are a rich source of information for database analysts, information scientists, and the end users of databases. In this study a group of scientists in astronomy and computer and information scientists work together to analyze a large volume of SQL log data generated by users of the Sloan Digital Sky Survey (SDSS) data archive in order to better understand users' data seeking behavior. While statistical analysis of such logs is useful at aggregated levels, efficiently exploring specific patterns of queries is often a challenging task due to the typically large volume of the data, multivariate features, and data requirements specified in SQL queries. To enable and facilitate effective and efficient exploration of the SDSS log data, we designed an interactive visualization tool, called the SDSS Log Viewer, which integrates time series visualization, text visualization, and dynamic query techniques. We describe two analysis scenarios of visual exploration of SDSS log data, including understanding unusually high daily query traffic and modeling the types of data seeking behaviors of massive query generators. The two scenarios demonstrate that the SDSS Log Viewer provides a novel and potentially valuable approach to support these targeted tasks.

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

International Nuclear Information System (INIS)

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

1985-01-01

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

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

Science.gov (United States)

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

2008-01-01

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

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.

Chlorination of uranium oxides with CCl4 using a mechanochemical method

International Nuclear Information System (INIS)

Kitawaki, Shinichi; Nagai, Takayuki; Sato, Nobuaki

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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.

Occupational exposure to chlorinated and petroleum solvents and mycosis fungoides

DEFF Research Database (Denmark)

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

2013-01-01

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

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

DEFF Research Database (Denmark)

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

2011-01-01

The fate of chlorinated ethenes in a large contaminant plume originating from a tetrachloroethene (PCE) source in a sandy aquifer in Denmark was investigated using novel methods including compound-specific carbon and chlorine isotope analysis and quantitative real-time polymerase chain reaction (q...... reduction by pyrite as indicated by the formation of cDCE and stable carbon isotope data. TCE and cDCE showed carbon isotope trends typical for reductive dechlorination with an initial depletion of 13C in the daughter products followed by an enrichment of 13C as degradation proceeded. At 1000 m downgradient......DCE. The significant enrichment of 13C in VC indicates that VC was transformed further, although the mechanismcould not be determined. The transformation of cDCEwas the rate limiting step as no accumulation of VC occurred. In summary, the study demonstrates that carbon–chlorine isotope analysis and qPCR combinedwith...

Static dictionaries on AC⁰ RAMs: query time (√log n/log log n) is necessary and sufficient

DEFF Research Database (Denmark)

Andersson, Arne; Miltersen, Peter Bro; Riis, Søren

1996-01-01

) on the time for answering membership queries in a set of size n when reasonable space is used for the data structure storing the set; the upper bound can be obtained using O(n) space, and the lower bound holds even if we allow space 2polylog n. Several variations of this result are also obtained. Among others......, we show a tradeoff between time and circuit depth under the unit-cost assumption: any RAM instruction set which permits a linear space, constant query time solution to the static dictionary problem must have an instruction of depth Ω(log w/log log to), where w is the word size of the machine (and log...

Prompt gamma-ray analysis of chlorine in superpozz cement concrete

Energy Technology Data Exchange (ETDEWEB)

Naqvi, A.A., E-mail: aanaqvi@kfupm.edu.sa [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Kalakada, Zameer [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Matouq, Faris A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Maslehuddin, M. [Center for Engineering Research, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Al-Amoudi, O.S.B. [Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Ur-Rehman, Khateeb [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

2012-11-21

The chlorine concentration in Superpozz (SPZ) cement concrete was analyzed using a newly designed prompt gamma-ray neutron activation (PGNAA) setup utilizing a portable neutron generator. The setup, which mainly consists of a neutron source along with its moderator placed side by side with a shielded gamma-ray detector, allows determining chloride concentration in a concrete structure from one side. The setup has been tested through chlorine detection in chloride-contaminated Superpozz (SPZ) cement concrete specimens using 6.11 and 2.86{+-}3.10 MeV chlorine prompt gamma-rays. The optimum 0.032{+-}0.012 wt% value of Minimum Detectable Concentration (MDC) of chlorine in SPZ cement concrete measured in this study shows a successful application of a portable neutron generator in chloride analysis of concrete structure for corrosion studies.

Dehalogenation of Chlorinated Hydroxybiphenyls by Fungal Laccase

Science.gov (United States)

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

2001-01-01

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

Processing well logging data, for example for verification and calibration of well logs

International Nuclear Information System (INIS)

Suau, J.; Boutemy, Y.

1981-01-01

A method is described of machine processing well logging data derived from borehole exploring devices which investigate earth formations traversed by boreholes. The method can be used for verifying and recalibrating logs, reconstructing missing logs and combining the data to form a statistical model of the traversed earth formations. (U.K.)

Thermodynamic analysis of the selective chlorination of electric arc furnace dust

International Nuclear Information System (INIS)

Pickles, C.A.

2009-01-01

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

Thermodynamic analysis of the selective chlorination of electric arc furnace dust

Energy Technology Data Exchange (ETDEWEB)

Pickles, C.A., E-mail: pickles-c@mine.queensu.ca [Department of Mining Engineering, Queen' s University, Kingston, Ontario, K7L 3N6 (Canada)

2009-07-30

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

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

Science.gov (United States)

Pickles, C A

2009-07-30

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

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

Science.gov (United States)

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

2010-04-01

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

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.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

International Nuclear Information System (INIS)

Sun Yingxue; Wu Qianyuan; Hu Hongying; Tian Jie

2009-01-01

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

La logística integral como ventaja competitiva y sistema logístico

Directory of Open Access Journals (Sweden)

Mario Anselmo Martínez gallardo

2013-07-01

Full Text Available Esta investigación analiza la logística integral como una ventaja competitiva y el sistema logístico. Es opinión de los autores que la logística integral es esencial para el intercambio de mercancías, toda vez que reduce costos y hace más ágil la actividad comercial. La utilización de esta logística representa una ventaja competitiva con respecto de otras empresas por la optimización del capital y ahorro de tiempo.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-01-15

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

Chlorine and bromine contents in tobacco and tobacco smoke

International Nuclear Information System (INIS)

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

1990-01-01

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

Experimental and Theoretical Studies of Atmosphereic Inorganic Chlorine Chemistry

Science.gov (United States)

Sander, Stanley P.; Friedl, Randall R.

1993-01-01

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

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

Science.gov (United States)

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

2017-09-15

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

Analysis of chest image performance in patients with acute chlorine poisoning

International Nuclear Information System (INIS)

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

2012-01-01

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

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.

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

International Nuclear Information System (INIS)

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

1991-01-01

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

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

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

Directory of Open Access Journals (Sweden)

Qais Iqbal

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

The geochemistry of stable chlorine and bromine isotopes

Energy Technology Data Exchange (ETDEWEB)

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

2014-11-01

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

Accumulation of chlorinated benzenes in earthworms

Science.gov (United States)

Beyer, W.N.

1996-01-01

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

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

International Nuclear Information System (INIS)

Yu, Haili; Zheng, Lei

2016-01-01

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

The log S -log N distribution of gamma ray brust

International Nuclear Information System (INIS)

Yamagami, Takamasa; Nishimura, Jun; Fujii, Masami

1982-01-01

The relation between the size S and the frequency N of gamma ray burst has been studied. This relation may be determined from the celestial distribution of gamma ray burst sources. The present analysis gives that the log S - log N relation for any direction is determined by the celestial distribution of gamma ray burst sources. The observed bursts were analyzed. The celestial distribution of gamma ray burst sources was observed by the satellites of USSR. The results showed that the distribution seemed to be isotropic. However, the calculated log S - log N relation based on the isotropic distribution wasF in disagreement with the observed ones. As the result of analysis, it was found that the observed bursts missed low energy part because of the threshold of detectors. The levels of discrimination of detection were not clear. When a proper threshold level is set for each type of burst, and the size of bursts is determined, the above mentioned discrepancy will be deleted regardless of luminosity and the spatial distribution of bursts. (Kato, T.)

Ametryn degradation by aqueous chlorine: Kinetics and reaction influences

International Nuclear Information System (INIS)

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

2009-01-01

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

Digital mineral logging system

International Nuclear Information System (INIS)

West, J.B.

1980-01-01

A digital mineral logging system acquires data from a mineral logging tool passing through a borehole and transmits the data uphole to an electronic digital signal processor. A predetermined combination of sensors, including a deviometer, is located in a logging tool for the acquisition of the desired data as the logging tool is raised from the borehole. Sensor data in analog format is converted in the logging tool to a digital format and periodically batch transmitted to the surface at a predetermined sampling rate. An identification code is provided for each mineral logging tool, and the code is transmitted to the surface along with the sensor data. The self-identifying tool code is transmitted to the digital signal processor to identify the code against a stored list of the range of numbers assigned to that type of tool. The data is transmitted up the d-c power lines of the tool by a frequency shift key transmission technique. At the surface, a frequency shift key demodulation unit transmits the decoupled data to an asynchronous receiver interfaced to the electronic digital signal processor. During a recording phase, the signals from the logging tool are read by the electronic digital signal processor and stored for later processing. During a calculating phase, the stored data is processed by the digital signal processor and the results are outputted to a printer or plotter, or both

Chlorination and Carbochlorination of Cerium Oxide

International Nuclear Information System (INIS)

Esquivel, Marcelo; Bohe, Ana; Pasquevich, Daniel

2000-01-01

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

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

NARCIS (Netherlands)

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

1985-01-01

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

Removals of pesticides and pesticide transformation products during drinking water treatment processes and their impact on mutagen formation potential after chlorination.

Science.gov (United States)

Matsushita, Taku; Morimoto, Ayako; Kuriyama, Taisuke; Matsumoto, Eisuke; Matsui, Yoshihiko; Shirasaki, Nobutaka; Kondo, Takashi; Takanashi, Hirokazu; Kameya, Takashi

2018-07-01

Removal efficiencies of 28 pesticide transformation products (TPs) and 15 parent pesticides during steps in drinking water treatment (coagulation-sedimentation, activated carbon adsorption, and ozonation) were estimated via laboratory-scale batch experiments, and the mechanisms underlying the removal at each step were elucidated via regression analyses. The removal via powdered activated carbon (PAC) treatment was correlated positively with the log K ow at pH 7. The adjusted coefficient of determination (r 2 ) increased when the energy level of the highest occupied molecular orbital (HOMO) was added as an explanatory variable, the suggestion being that adsorption onto PAC particles was largely governed by hydrophobic interactions. The residual error could be partly explained by π-π electron donor-acceptor interactions between the graphene surface of the PAC particles and the adsorbates. The removal via ozonation correlated positively with the energy level of the HOMO, probably because compounds with relatively high energy level HOMOs could more easily transfer an electron to the lowest unoccupied molecular orbital of ozone. Overall, the TPs tended to be more difficult to remove via PAC adsorption and ozonation than their parent pesticides. However, the TPs that were difficult to remove via PAC adsorption did not induce strong mutagenicity after chlorination, and the TPs that were associated with strong mutagenicity after chlorination could be removed via PAC adsorption. Therefore, PAC adsorption is hypothesized to be an effective method of treating drinking water to reduce the possibility of post-chlorination mutagenicity associated with both TPs and their parent pesticides. Copyright © 2018 Elsevier Ltd. All rights reserved.

Alkali and chlorine in biomass - a problem in connection with power generation. Alkali och klor i biomassa - ett problem vid elgenerering

Energy Technology Data Exchange (ETDEWEB)

Gaerdenaes, S

1991-06-04

The literature survey gives a summary of the macronutrients and the variations in different biomass. Especially alkali is discussed. The work gives an account of difficult biomass fuels which will rather be used in hot water boilers than in gas turbines of power generation. The amount of alkali and chlorine increases from hardwood < softwood < salix < straw from Phalaris arundineral (harvested during summer). The range of variation was 10-25 between the assortments. The fraction division is the most important factor for the variation. Alkaline content also depend on age, soil fertility and storage methods. Seasonal aspects and local depositions are less important. However, great care should be taken with fuel from coastal areas because of chlorine depositions. Gasification of biomass to produce gas for combined cycle operation poses special problems. The alkali content of logging residues have to be cleaned up to approximately 99 % in the example. When the process gas is originated from straw or salix the separation have to be even more efficient. The method used for the separation could be based on wet or dry technic hotgas cleanup has not yet been tested in large scale but seems to be a promising method to attain high degree of separation and power efficiency. Difficulties of power generation make straw fuels less interesting. The content of alkali and chlorine can be considerably decreased by changing the way of fertilization and cultivation period. If everything turns out well, this would give a complementary for gasification or steam generation. To the greates part this fuels will however be used in pure heat production. (author).

78 FR 66767 - Chlorinated Isocyanurates From China and Japan

Science.gov (United States)

2013-11-06

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

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

International Nuclear Information System (INIS)

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

2015-01-01

Neutron activation analysis using decay counting of the activated element is a well-established method in elemental analysis. However, for chlorine there is a better alternative to measuring decay of the short-lived activation product chlorine-38 (t 1/2 = 37.24 min) – accelerator mass spectrometry (AMS) of 36 Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t 1/2 = 301 ka) allow for determination of chlorine down to ppb-levels using practical sample sizes and common exposure durations. The combination of neutron activation and AMS can be employed for a few other elements (nitrogen, thorium, and uranium) as well. For bulk solid samples an advantage of the method is that lab contamination can be rendered irrelevant. The chlorine-35 in the sample is activated to chlorine-36, and surface chlorine can be removed after the irradiation. Subsequent laboratory contamination, however, will not carry a prominent chlorine-36 signature. After sample dissolution and addition of sufficient amounts of stable chlorine carrier the produced chlorine-36 and thus the original chlorine-35 of the sample can be determined using AMS. We have developed and applied the method for analysis of chlorine in steel samples. The chlorine content of steel is of interest to nuclear industry, precisely because of above mentioned high neutron capture cross section for chlorine-35, which leads to accumulation of chlorine-36 as long-term nuclear waste. The samples were irradiated at the TRIGA Mark II reactor of the Atominstitut in Vienna and the 36 Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for 36 Cl/Cl analysis.

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-10-15

Neutron activation analysis using decay counting of the activated element is a well-established method in elemental analysis. However, for chlorine there is a better alternative to measuring decay of the short-lived activation product chlorine-38 (t{sub 1/2} = 37.24 min) – accelerator mass spectrometry (AMS) of {sup 36}Cl: the relatively high neutron capture cross section of chlorine-35 for thermal neutrons (43.7 b) and combined the AMS technique for chlorine-36 (t{sub 1/2} = 301 ka) allow for determination of chlorine down to ppb-levels using practical sample sizes and common exposure durations. The combination of neutron activation and AMS can be employed for a few other elements (nitrogen, thorium, and uranium) as well. For bulk solid samples an advantage of the method is that lab contamination can be rendered irrelevant. The chlorine-35 in the sample is activated to chlorine-36, and surface chlorine can be removed after the irradiation. Subsequent laboratory contamination, however, will not carry a prominent chlorine-36 signature. After sample dissolution and addition of sufficient amounts of stable chlorine carrier the produced chlorine-36 and thus the original chlorine-35 of the sample can be determined using AMS. We have developed and applied the method for analysis of chlorine in steel samples. The chlorine content of steel is of interest to nuclear industry, precisely because of above mentioned high neutron capture cross section for chlorine-35, which leads to accumulation of chlorine-36 as long-term nuclear waste. The samples were irradiated at the TRIGA Mark II reactor of the Atominstitut in Vienna and the {sup 36}Cl-AMS setup at the Vienna Environmental Research Accelerator (VERA) was used for {sup 36}Cl/Cl analysis.

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.

Release of Chlorine and Sulfur during Biomass Torrefaction and Pyrolysis

DEFF Research Database (Denmark)

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

2014-01-01

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

Chlorination of niobium oxide in the presence of carbon monoxide

International Nuclear Information System (INIS)

Freitas, L.R. de

1984-01-01

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

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

Science.gov (United States)

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

2015-10-20

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

Water Chlorination for human consumption

International Nuclear Information System (INIS)

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

1999-01-01

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

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

Science.gov (United States)

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

2009-05-15

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

Estimation of the non records logs from existing logs using artificial neural networks

Directory of Open Access Journals (Sweden)

Mehdi Mohammad Salehi

2017-12-01

Full Text Available Finding the information of the hydrocarbon reservoirs from well logs is one of the main objectives of the engineers. But, missing the log records (due to many reasons such as broken instruments, unsuitable borehole and etc. is a major challenge to achieve it. Prediction of the density and resistivity logs (Rt, DT and LLS from the conventional wire-line logs in one of the Iranian southwest oil fields is the main purpose of this study. Multilayer neural network was applied to develop an intelligent predictive model for prediction of the logs. A total of 3000 data sets from 3 wells (A, B and C of the studied field were used. Among them, the data of A, B and C wells were used to constructing and testing the model, respectively. To evaluate the performance of the model, the mean square error (MSE and correlation coefficient (R2 in the test data were calculated. A comparison between the MSE of the proposed model and recently intelligent models shows that the proposed model is more accurate than others. Acceptable accuracy and using conventional well logging data are the highlight advantages of the proposed intelligent model.

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

Science.gov (United States)

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

Hazard Assessment on Chlorine Distribution Use of Chemical Transportation Risk Index

International Nuclear Information System (INIS)

Kim, Jeong Gon; Byun, Hun Soo

2014-01-01

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

Hazard Assessment on Chlorine Distribution Use of Chemical Transportation Risk Index

Energy Technology Data Exchange (ETDEWEB)

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

2014-12-15

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

Metabolic fate of chlorinated paraffins

International Nuclear Information System (INIS)

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

1982-01-01

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

Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

International Nuclear Information System (INIS)

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

2014-01-01

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

Spectrographic determination of chlorine and fluorine

International Nuclear Information System (INIS)

Contamin, G.

1965-04-01

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

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

Science.gov (United States)

Gottardi, W; Karl, A

1991-05-01

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

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

Science.gov (United States)

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

2016-01-01

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

Geophysical well logging operations and log analysis in Geothermal Well Desert Peak No. B-23-1

Energy Technology Data Exchange (ETDEWEB)

Sethi, D.K.; Fertl, W.H.

1980-03-01

Geothermal Well Desert Peak No. B-23-1 was logged by Dresser Atlas during April/May 1979 to a total depth of 2939 m (9642 ft). A temperature of 209/sup 0/C (408/sup 0/F) was observed on the maximum thermometer run with one of the logging tools. Borehole tools rated to a maximum temperature of 204.4/sup 0/C (400/sup 0/F) were utilized for logging except for the Densilog tool, which was from the other set of borehole instruments, rated to a still higher temperature, i.e., 260/sup 0/C (500/sup 0/F). The quality of the logs recorded and the environmental effects on the log response have been considered. The log response in the unusual lithologies of igneous and metamorphic formations encountered in this well could be correlated with the drill cutting data. An empirical, statistical log interpretation approach has made it possible to obtain meaningful information on the rocks penetrated. Various crossplots/histograms of the corrected log data have been generated on the computer. These are found to provide good resolution between the lithological units in the rock sequence. The crossplotting techniques and the statistical approach were combined with the drill cutting descriptions in order to arrive at the lithological characteristics. The results of log analysis and recommendations for logging of future wells have been included.

Theoretical and Numerical Study of Seismoelectric Logs for Logging While Drilling (LWD

Directory of Open Access Journals (Sweden)

Sun Xiang-Yang

2017-01-01

Full Text Available When the acoustic field propagates in the porous medium, the electromagnetic wave can be induced by the seismoelectric effects which can be used in the logging. This paper studies the seismoelectric wave field and deduces the formulations of the acoustic and electromagnetic field of the liquid in the well, and gives the acoustic and electromagnetic boundary conditions between the driller collar and the log liquid, when the driller collar is added. We also do the numerical simulation of the seismoelectric wave field excited by monopole source, study the velocity dispersion characteristics of the acoustic and electromagnetic field, and investigate the detective depth of the seismoelectric logs. Through the simulation we know the seismoelectric logs can avoid the interference of drill collar wave. This paper also provides theoretical guidance for the design of receiving antenna.

Face logging in Copenhagen Limestone, Denmark

DEFF Research Database (Denmark)

Jakobsen, Lisa; Foged, Niels Nielsen; Erichsen, Lars

2015-01-01

tunnel in Copenhagen more than 2.5 km face logs were made in 467 locations at underground stations, shafts, caverns and along bored tunnels. Over 160 geotechnical boreholes, many with geophysical logging were executed prior to construction works. The bedrock consists of Paleogene "Copenhagen limestone......The requirement for excavation support can be assessed from face logging. Face logs can also improve our knowledge of lithological and structural conditions within bedrock and supplement information from boreholes and geophysical logs. During the construction of 8 km metro tunnel and 4 km heating....... The induration degrees recorded in face logs and boreholes are compared and correlated. Distinct geophysical log markers are used to divide the limestone into three units. These marker horizons are correlated between face logs and geotechnical boreholes. A 3D model of the strength variations recorded within...

Gene expression changes in blood RNA after swimming in a chlorinated pool.

Science.gov (United States)

Salas, Lucas A; Font-Ribera, Laia; Bustamante, Mariona; Sumoy, Lauro; Grimalt, Joan O; Bonnin, Sarah; Aguilar, Maria; Mattlin, Heidi; Hummel, Manuela; Ferrer, Anna; Kogevinas, Manolis; Villanueva, Cristina M

2017-08-01

Exposure to disinfection by-products (DBP) such as trihalomethanes (THM) in swimming pools has been linked to adverse health effects in humans, but their biological mechanisms are unclear. We evaluated short-term changes in blood gene expression of adult recreational swimmers after swimming in a chlorinated pool. Volunteers swam 40min in an indoor chlorinated pool. Blood samples were drawn and four THM (chloroform, bromodichloromethane, dibromochloromethane and bromoform) were measured in exhaled breath before and after swimming. Intensity of physical activity was measured as metabolic equivalents (METs). Gene expression in whole blood mRNA was evaluated using IlluminaHumanHT-12v3 Expression-BeadChip. Linear mixed models were used to evaluate the relationship between gene expression changes and THM exposure. Thirty-seven before-after pairs were analyzed. The median increase from baseline to after swimming were: 0.7 to 2.3 for MET, and 1.4 to 7.1μg/m 3 for exhaled total THM (sum of the four THM). Exhaled THM increased on average 0.94μg/m 3 per 1 MET. While 1643 probes were differentially expressed post-exposure. Of them, 189 were also associated with exhaled levels of individual/total THM or MET after False Discovery Rate. The observed associations with the exhaled THM were low to moderate (Log-fold change range: -0.17 to 0.15). In conclusion, we identified short-term gene expression changes associated with swimming in a pool that were minor in magnitude and their biological meaning was unspecific. The high collinearity between exhaled THM levels and intensity of physical activity precluded mutually adjusted models with both covariates. These exploratory results should be validated in future studies. Copyright © 2017. Published by Elsevier B.V.

The potential feasibility of chlorinic photosynthesis on exoplanets.

Science.gov (United States)

Haas, Johnson R

2010-11-01

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

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

International Nuclear Information System (INIS)

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

1978-01-01

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

Electrochemically activated water as an alternative to chlorine for decentralized disinfection

KAUST Repository

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

2011-01-01

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

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.

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

International Nuclear Information System (INIS)

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

1983-01-01

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

Chlorin derivatives for potential use in BNCT

International Nuclear Information System (INIS)

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

2000-01-01

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

DFT application for chlorin derivatives photosensitizer drugs modeling

Science.gov (United States)

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

2018-04-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-07-01

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

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

Science.gov (United States)

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

2018-02-01

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

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

Science.gov (United States)

Fisher, N; Berry, R; Hardy, J

1983-08-01

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

Log4J

CERN Document Server

Perry, Steven

2009-01-01

Log4j has been around for a while now, and it seems like so many applications use it. I've used it in my applications for years now, and I'll bet you have too. But every time I need to do something with log4j I've never done before I find myself searching for examples of how to do whatever that is, and I don't usually have much luck. I believe the reason for this is that there is a not a great deal of useful information about log4j, either in print or on the Internet. The information is too simple to be of real-world use, too complicated to be distilled quickly (which is what most developers

Bio-remediation of aquifers polluted by chlorinated solvents

International Nuclear Information System (INIS)

Fayolle, F.

1996-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-08-15

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

Chlorine signal attenuation in concrete.

Science.gov (United States)

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

2015-11-01

The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2014-05-01

Disinfection is the last treatment stage of a Drinking Water Treatment Plant (DWTP) and is carried out to maintain a residual concentration of disinfectant in the water distribution system. Chlorine dioxide (ClO2) is a widely used chemical employed for this purpose. The aim of this work was to evaluate the influence of several treatments on chlorine dioxide consumption and on chlorite and chlorate formation in the final oxidation/disinfection stage. A number of tests was performed at laboratory scale employing water samples collected from the DWTP of Cremona (Italy). The following processes were studied: oxidation with potassium permanganate, chlorine dioxide and sodium hypochlorite, coagulation/flocculation with ferric chloride and aluminum sulfate, filtration and adsorption onto activated carbon. The results showed that the chlorine dioxide demand is high if sodium hypochlorite or potassium permanganate are employed in pre-oxidation. On the other hand, chlorine dioxide leads to the highest production of chlorite and chlorate. The coagulation/flocculation process after pre-oxidation shows that chlorine dioxide demand decreases if potassium permanganate is employed as an oxidant, both with ferric chloride and aluminum sulfate. Therefore, the combination of these processes leads to a lower production of chlorite and chlorate. Aluminum sulfate is preferable in terms of the chlorine dioxide demand reduction and minimization of the chlorite and chlorate formation. Activated carbon is the most effective solution as it reduced the chlorine dioxide consumption by about 50% and the DBP formation by about 20-40%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Unsupervised signature extraction from forensic logs

NARCIS (Netherlands)

Thaler, S.M.; Menkovski, V.; Petkovic, M.; Altun, Y.; Das, K.; Mielikäinen, T.; Malerba, D.; Stefanowski, J.; Read, J.; Žitnik, M.; Ceci, M.

2017-01-01

Signature extraction is a key part of forensic log analysis. It involves recognizing patterns in log lines such that log lines that originated from the same line of code are grouped together. A log signature consists of immutable parts and mutable parts. The immutable parts define the signature, and

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.

2.2. Chlorination of pre-baked danburite with reducer

International Nuclear Information System (INIS)

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

2013-01-01

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

Survey of potential chlorine production processes. Final report

Energy Technology Data Exchange (ETDEWEB)

1979-04-01

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

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

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

Science.gov (United States)

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

2011-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Log-balanced combinatorial sequences

Directory of Open Access Journals (Sweden)

Tomislav Došlic

2005-01-01

Full Text Available We consider log-convex sequences that satisfy an additional constraint imposed on their rate of growth. We call such sequences log-balanced. It is shown that all such sequences satisfy a pair of double inequalities. Sufficient conditions for log-balancedness are given for the case when the sequence satisfies a two- (or more- term linear recurrence. It is shown that many combinatorially interesting sequences belong to this class, and, as a consequence, that the above-mentioned double inequalities are valid for all of them.

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

International Nuclear Information System (INIS)

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

2007-01-01

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

LOG2MARKUP: State module to transform a Stata text log into a markup document

DEFF Research Database (Denmark)

2016-01-01

log2markup extract parts of the text version from the Stata log command and transform the logfile into a markup based document with the same name, but with extension markup (or otherwise specified in option extension) instead of log. The author usually uses markdown for writing documents. However...

Fraction of organic carbon predicts labile desorption rates of chlorinated organic pollutants in laboratory-spiked geosorbents.

Science.gov (United States)

Ginsbach, Jake W; Killops, Kato L; Olsen, Robert M; Peterson, Brittney; Dunnivant, Frank M

2010-05-01

The resuspension of large volumes of sediments that are contaminated with chlorinated pollutants continues to threaten environmental quality and human health. Whereas kinetic models are more accurate for estimating the environmental impact of these events, their widespread use is substantially hampered by the need for costly, time-consuming, site-specific kinetics experiments. The present study investigated the development of a predictive model for desorption rates from easily measurable sorbent and pollutant properties by examining the relationship between the fraction of organic carbon (fOC) and labile release rates. Duplicate desorption measurements were performed on 46 unique combinations of pollutants and sorbents with fOC values ranging from 0.001 to 0.150. Labile desorption rate constants indicate that release rates predominantly depend upon the fOC in the geosorbent. Previous theoretical models, such as the macro-mesopore and organic matter (MOM) diffusion model, have predicted such a relationship but could not accurately predict the experimental rate constants collected in the present study. An empirical model was successfully developed to correlate the labile desorption rate constant (krap) to the fraction of organic material where log(krap)=0.291-0.785 . log(fOC). These results provide the first experimental evidence that kinetic pollution releases during resuspension events are governed by the fOC content in natural geosorbents. Copyright (c) 2010 SETAC.

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

Science.gov (United States)

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

2006-12-01

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

Inactivation of Giardia muris cysts by free chlorine.

OpenAIRE

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

1987-01-01

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

Combined treatment of Pseudomonas aeruginosa biofilms with bacteriophages and chlorine.

Science.gov (United States)

Zhang, Yanyan; Hu, Zhiqiang

2013-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-01

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

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

International Nuclear Information System (INIS)

Hortiguela, Ruben; Corchon, Fernando; Villesccas, Gilberto

2012-09-01

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

Hydrogen/Chlorine exchange reactions of gaseous carbanions.

Science.gov (United States)

Chen, Hao; Cooks, R Graham; Meurer, Eduardo C; Eberlin, Marcos N

2005-12-01

Gas-phase reactions of three typical carbanions CH(2)NO(2)(-), CH(2)CN(-), and CH(2)S(O)CH(3)(-) with the chloromethanes CH(2)Cl(2), CHCl(3), and CCl(4), examined by tandem mass spectrometry, show a novel hydrogen/chlorine exchange reaction. For example, reaction between the nitromethyl anion CH(2)NO(2)(-) and carbon tetrachloride CCl(4) forms the ion CHClNO(2)(-). The suggested reaction mechanism involves nucleophilic attack by CH(2)NO(2)(-) at the chlorine of CCl(4) followed by proton transfer within the resulting complex [CH(2)ClNO(2) + CCl(3)(-)] to form CHClNO(2)(-) and CHCl(3). Two other carbanions CH(2)CN(-) and CH(2)S(O)CH(3)(-) also undergo the novel hydrogen/chlorine exchange reactions with CCl(4) but to a much smaller extent, their higher nucleophilicities favoring competitive nucleophilic attack reactions. Proton abstraction is the exclusive pathway in the reactions of these carbanions with CHCl(3). While CH(2)CN(-) and CH(2)S(O)CH(3)(-) promote mainly proton abstraction and nucleophilic displacement in reactions with CH(2)Cl(2), CH(2)NO(2)(-) does not react.

Radiolytic degradation of chlorinated hydrocarbons in water

Energy Technology Data Exchange (ETDEWEB)

Wu, Xing-Zheng; Yamamoto, Takeshi [Fukui Univ., Faculty of Engineering, Dept. of Materials Science and Engineering, Fukui (Japan); Hatashita, Masanori [The Wakasa Wan Energy Research Center, Research Dept., Tsuruga, Fukui (Japan)

2002-11-01

Radiolytic degradation of chlorinated hydrocarbons (chloroform, trichloroethylene, and tetrachloroethylene) in water was carried out. Water solutions of the chlorinated hydrocarbons with different concentrations were irradiated with {gamma} rays. Concentrations of methane, ethane, CO, CO{sub 2}, H{sub 2}, and O{sub 2} after the irradiation were determined by gas chromatography. Concentration of chloride ion in the irradiated sample was determined by ion chromatography. Experimental results show that radiolytic degradation of the chlorinated hydrocarbon increased with the radiation dose. Methane, ethane, CO{sub 2}, H{sub 2}, and Cl{sup -} concentrations increased with the radiation dose and the sample concentration. On the other hand, O{sub 2} concentration decreased with the radiation dose and the sample concentration. When sample concentration was high, dissolved oxygen might be not enough for converting most of the C atoms in the sample into CO{sub 2}. This resulted in a low decomposition ratio. Addition of H{sub 2}O{sub 2} as an oxygen resource could increase the decomposition ratio greatly. Furthermore, gas chromatography-mass spectroscopy was applied to identify some intermediates of the radiolytic dehalogenation. Radiolytic degradation mechanisms are also discussed. (author)

Analysis of alternative flow sheets for the hybrid chlorine cycle

Energy Technology Data Exchange (ETDEWEB)

Gooding, Charles H. [Department of Chemical and Biomolecular Engineering, 209 Earle Hall, Clemson University, Clemson, SC 29634-0909 (United States)

2009-05-15

This paper reports the results of the most complete conceptual study conducted to date on hydrogen production using the hybrid chlorine cycle. Three alternative process flow sheets were developed, each capable of producing hydrogen at 35 C (308 K) and 21 bar. The alternative approaches differ primarily in the way HCl is isolated and converted to hydrogen and chlorine gases. Aspen Plus trademark simulation software was used to model the unit processes, supplemented where necessary by custom Excel spreadsheets. Major equipment was sized for a 200-million kg/yr plant; feasible materials of construction were identified; fixed capital investments and variable costs were estimated. Estimated net thermal efficiencies of the flow sheets range from 30% to 36%, based on the lower heating value of the hydrogen produced. With electrical power valued at $0.05/kWh, the cost of hydrogen produced by the hybrid chlorine cycle would be at least $3/kg. These results indicate that direct electrolysis of water is a more attractive way to produce hydrogen than any presently conceived version of the hybrid chlorine cycle. (author)

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...

Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

Energy Technology Data Exchange (ETDEWEB)

Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Novak, Spencer; Richardson, Kathleen [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Materials Science and Engineering, COMSET, Clemson University, Clemson, South Carolina 29634 (United States); Fathpour, Sasan, E-mail: fathpour@creol.ucf.edu [CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States)

2015-03-16

A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes.

Low-loss, submicron chalcogenide integrated photonics with chlorine plasma etching

International Nuclear Information System (INIS)

Chiles, Jeff; Malinowski, Marcin; Rao, Ashutosh; Novak, Spencer; Richardson, Kathleen; Fathpour, Sasan

2015-01-01

A chlorine plasma etching-based method for the fabrication of high-performance chalcogenide-based integrated photonics on silicon substrates is presented. By optimizing the etching conditions, chlorine plasma is employed to produce extremely low-roughness etched sidewalls on waveguides with minimal penalty to propagation loss. Using this fabrication method, microring resonators with record-high intrinsic Q-factors as high as 450 000 and a corresponding propagation loss as low as 0.42 dB/cm are demonstrated in submicron chalcogenide waveguides. Furthermore, the developed chlorine plasma etching process is utilized to demonstrate fiber-to-waveguide grating couplers in chalcogenide photonics with high power coupling efficiency of 37% for transverse-electric polarized modes

Radiometric well logging instruments

International Nuclear Information System (INIS)

Davydov, A.V.

1975-01-01

The technical properties of well instruments for radioactive logging used in the radiometric logging complexes PKS-1000-1 (''Sond-1'') and PRKS-2 (''Vitok-2'') are described. The main features of the electric circuit of the measuring channels are given

Hardwood log supply: a broader perspective

Science.gov (United States)

Iris Montague; Adri Andersch; Jan Wiedenbeck; Urs. Buehlmann

2015-01-01

At regional and state meetings we talk with others in our business about the problems we face: log exports, log quality, log markets, logger shortages, cash flow problems, the weather. These are familiar talking points and real and persistent problems. But what is the relative importance of these problems for log procurement in different regions of...

Study of the production of Zirconium tetracheoride by chlorination of its oxide

International Nuclear Information System (INIS)

Seo, E.S.M.; Abrao, A.

1987-08-01

This work describes the studies carried out on the production of zirconium tetrachloride by chlorianation of pure zirconium oxide with (a) carbon tetrachloride and (b) chlorine in the presence of carbon. In the process of chlorination with carbon tetrachloride it has been determined that efficiency increases with the rising of temperature between 450 and 750 0 C. The flow rate of the carbon tetrachloride vapour used was 1.50L/min. For the zirconium oxide chlorination in the presence of carbon, the study has been carried out at temperatures between 700 and 850 0 C and the flow rate of the chlorine gas used in the process was 0,50/Lmin. Pure zirconium oxide chlorination as well as zirconium oxide-carbon mixture chlrorination have been studied in connection with the time of reaction at different temperatures and the apparent rate constants, the activation energies, the order of reaction in relation to the concentration of the gases (CCl 4 and Cl 2 ) and the content of carbon in the pellet have all been determined. (Author) [pt

UV/chlorine treatment of carbamazepine: Transformation products and their formation kinetics.

Science.gov (United States)

Pan, Yanheng; Cheng, ShuangShuang; Yang, Xin; Ren, Jingyue; Fang, Jingyun; Shang, Chii; Song, Weihua; Lian, Lushi; Zhang, Xinran

2017-06-01

Carbamazepine (CBZ) is one of the pharmaceuticals most frequently detected in the aqueous environment. This study investigated the transformation products when CBZ is degraded by chlorine under ultraviolet (UV) irradiation (the UV/chlorine process). Detailed pathways for the degradation of CBZ were elucidated using ultra-high performance liquid chromatography (UHPLC)-quadrupole time-of-flight mass spectrometry (QTOF-MS). CBZ is readily degraded by hydroxyl radicals (HO) and chlorine radicals (Cl) in the UV/chlorine process, and 24 transformation products were identified. The products indicate that the 10,11-double bond and aromatic ring in CBZ are the sites most susceptible to attack by HO and Cl. Subsequent reaction produces hydroxylated and chlorinated aromatic ring products. Four specific products were quantified and their evolution was related with the chlorine dose, pH, and natural organic matter concentration. Their yields showed an increase followed by a decreasing trend with prolonged reaction time. CBZ-10,11-epoxide (I), the main quantified transformation product from HO oxidation, was observed with a peak transformation yield of 3-32% depending on the conditions. The more toxic acridine (IV) was formed involving both HO and Cl with peak transformation yields of 0.4-1%. All four quantified products together amounted to a peak transformation yield of 34.5%. The potential toxicity of the transformation products was assayed by evaluating their inhibition of the bioluminescence of the bacterium Vibrio Fischeri. The inhibition increased at first and the decreased at longer reaction times, which was in parallel with the evolution of transformation products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorine Dioxide: The State of Science, Regulatory, Environmental Issues, and Case Histories

National Research Council Canada - National Science Library

Burton, Dennis

2001-01-01

The use of chlorine by electric utilities and other surface water users to inhibit biofouling and the chlorination of wastewater by POTWs to eliminate the discharge of pathogenic organisms are widespread practices...

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

Science.gov (United States)

Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

1995-01-01

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus. PMID:7793931

Phenotypic and genetic diversity of chlorine-resistant Methylobacterium strains isolated from various environments.

Science.gov (United States)

Hiraishi, A; Furuhata, K; Matsumoto, A; Koike, K A; Fukuyama, M; Tabuchi, K

1995-06-01

Strains of pink-pigmented facultative methylotrophs which were isolated previously from various environments and assigned tentatively to the genus Methylobacterium were characterized in comparison with authentic strains of previously known species of this genus. Most of the isolates derived from chlorinated water supplies exhibited resistance to chlorine, whereas 29 to 40% of the isolates from air, natural aquatic environments, and clinical materials were chlorine resistant. None of the tested authentic strains of Methylobacterium species obtained from culture collections exhibited chlorine resistance. Numerical analysis of phenotypic profiles showed that the test organisms tested were separated from each other except M. organophilum and M. rhodesianum. The chlorine-resistant isolates were randomly distributed among all clusters. The 16S ribosomal DNA (rDNA) sequence-based phylogenetic analyses showed that representatives of the isolates together with known Methylobacterium species formed a line of descent distinct from that of members of related genera in the alpha-2 subclass of the Proteobacteria and were divided into three subclusters within the Methylobacterium group. These results demonstrate that there is phenotypic and genetic diversity among chlorine-resistant Methylobacterium strains within the genus.

Semi-automatic logarithmic converter of logs

International Nuclear Information System (INIS)

Gol'dman, Z.A.; Bondar's, V.V.

1974-01-01

Semi-automatic logarithmic converter of logging charts. An original semi-automatic converter was developed for use in converting BK resistance logging charts and the time interval, ΔT, of acoustic logs from a linear to a logarithmic scale with a specific ratio for subsequent combining of them with neutron-gamma logging charts in operative interpretation of logging materials by a normalization method. The converter can be used to increase productivity by giving curves different from those obtained in manual, pointwise processing. The equipment operates reliably and is simple in use. (author)

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

International Nuclear Information System (INIS)

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

1993-01-01

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

Biodegradation of chlorinated solvents in a water unsaturated topsoil

DEFF Research Database (Denmark)

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

2003-01-01

In order to investigate topsoils as potential sinks for chlorinated solvents from the atmosphere, the degradation of trichloromethane (CHCl3), 1,1,1-trichloroethane (CH3CCl3), tetrachloromethane (CCl4), trichloroethene (C2HCl3) and tetrachloroethene (C2Cl4) was studied in anoxic laboratory....... The headspace concentrations of all the chlorinated solvents except CH3CCl3 were significantly (P less than or equal to 0.05) lower after 41 days in biologically active batches as compared to sterile batches. For the compounds with significantly decreasing headspace concentrations, the decline was the least...... experiments designed to simulate denitrifying conditions in water unsanstrated by measuring the release of N-15 in N-2 to the headspace from added N-15 labeled nitrate. The degradation of chlorinated aliphatic compounds was followed by measuring their concentrations in the headspace above the soil...

Power to the logs!

CERN Multimedia

CERN. Geneva; MACMAHON, Joseph

2015-01-01

Are you tired of using grep, vi and emacs to read your logs? Do you feel like you’re missing the big picture? Does the word "statistics" put a smile on your face? Then it’s time to give power to the logs!

Chlorination separation of uranium, thorium, and radium from low-grade ores

International Nuclear Information System (INIS)

Sastri, V.S.; Perumareddi, J.R.

1995-01-01

Low-temperature chlorination of low-grade uranium ores containing uranium in the 0.02 to 0.06% range, thorium in the 0.036 to 0.12% range, and radium in the 70 to 200 pci/g range resulted in the extraction of >90% of the constituents. The residue left after chlorination was found to be innocuous and suitable for disposal as a waste acceptable to the environment. Use of sodium chloride in the charge was useful in reducing the chlorination temperature and in the formation of nonvolatile anionic chloro complexes of the metal ions in the ore

A study of the characteristics of indium tin oxide after chlorine electro-chemical treatment

Energy Technology Data Exchange (ETDEWEB)

Kim, Moonsoo; Kim, Jongmin; Cho, Jaehee; Kim, Hyunwoo; Lee, Nayoung; Choi, Byoungdeog, E-mail: bdchoi@skku.edu

2016-10-15

Graphical abstract: The presence of Chlorine in the outer surface resulted in a highly electro-negative surface states and an increase in the vacuum energy level. - Highlights: • We investigated the influence of chlorine surface treatment on ITO properties. • Chlorination induced the change of the electro-static potential in the outer surface. • Chlorine electro-chemical treatment of ITO is a simple, fast and effective technique. - Abstract: In this work, we investigate the influence of a chlorine-based electro-chemical surface treatment on the characteristics of indium tin oxide (ITO) including the work function, chemical composition, and phase transition. The treated ITOs were characterized using X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS), 4-point probe measurements, and grazing incidence X-ray diffraction (GI-XRD). We confirmed a change of the chemical composition in the near-surface region of the ITO and the formation of indium-chlorine (In-Cl) bonds and surface dipoles (via XPS). In particular, the change of the electro-static potential in the outer surface was caused by chlorination. Due to the vacuum-level shift after the electro-chemical treatment in a dilute hydrochloric acid, the ITO work function was increased by ∼0.43 eV (via UPS); furthermore, the electro-negativity of the chlorine anions attracted electrons to emit them from the hole transport layer (HTL) to the ITO anodes, resulting in an increase of the hole-injection efficiency.

Kinetics of AOX Formation in Chlorine Dioxide Bleaching of Bagasse Pulp

Directory of Open Access Journals (Sweden)

Shuangxi Nie

2014-07-01

Full Text Available In this paper, a kinetic model of the first chlorine dioxide bleaching stage (D0 in an elemental chlorine-free (ECF bleaching sequence is presented for bagasse pulps. The model is based on the rate of adsorbable organic halogen (AOX formation. The effects of the chlorine dioxide dosage, the sulfuric acid dosage, and the reaction temperature on the AOX content of wastewater are examined. The reaction of AOX formation could be divided into two periods. A large amount of AOX was formed rapidly within the first 10 min. Ten minutes later, the AOX formation rate significantly decreased. The kinetics could be expressed as: dW⁄dt=660.8•e^(-997.98/T 〖•[ClO〗_2 ]^0.877•[H2SO4 ]^0.355•W^(-1.065, where W is the AOX content, t is the bleaching time (min, T is the temperature (K, [ClO2] is the dosage of chlorine dioxide (kg/odt, and [H2SO4] is the dosage of sulfuric acid (kg/odt. The fit of the experiment results obtained for different temperatures, initial chlorine dioxide dosages, initial sulfuric acid dosages, and AOX content were very good, revealing the ability of the model to predict typical mill operating conditions.

Determination of chlorine in coal by X-ray fluorescence spectrometry method

Energy Technology Data Exchange (ETDEWEB)

Marek, S.; Bojarska, K. [Central Mining Institute, Katowice (Poland). Dept. of Environmental Monitoring

1997-12-31

Determination of chlorine contents in coal is essential for both environmental protection and its technological use. The existing method of chlorine determination in coal are titration methods which have considerable errors particularly in the low concentration range. The elaborated method with the use of X-ray fluorescence spectrometry in a comparison to the other methods is much faster and has better precision and accuracy. The principle of the method lies in the measurement of X-ray fluorescence radiation intensity which is emitted by chlorine in a sample and its comparison with standards. The calibration of the elaborated XRF method is based on natural coals having various concentrations of chlorine within the whole range of its occurrence in Polish coals. Concentrations for the calibration purpose were obtained by the determination of chlorine contents in selected coals by atomic absorption spectrometry method. The procedure of sample preparation for direct X-ray measurements, instrumental measuring conditions and the way of calibration curve preparation are described in the paper. All X-ray measurements were done with a Phillips sequential X-ray fluorescence spectrometer. A double anode Cr-Au X-ray tube with maximum power 3000 MW was used as the excitation source. 5 figs., 4 tabs.

Constraining wintertime sources of inorganic chlorine over the northeast United States

Science.gov (United States)

Haskins, J.; Jaegle, L.; Shah, V.; Lopez-Hilfiker, F.; Lee, B. H.; Campuzano Jost, P.; Schroder, J. C.; Day, D. A.; Fiddler, M. N.; Holloway, J. S.; Sullivan, A.; Veres, P. R.; Weber, R. J.; Dibb, J. E.; Brown, S. S.; Jimenez, J. L.; Thornton, J. A.

2017-12-01

Wintertime multiphase chlorine chemistry is thought to play a significant role in the regional distribution of oxidants, the lifetime of VOCs, and the transport of NOx downwind of urban sources. However, the sources and chemistry of reactive chlorine remain highly uncertain. During the WINTER 2015 aircraft campaign, the inorganic chlorine budget was dominated by HCl (g) and total particulate chloride, accounting for greater than 85% of the total chlorine budget within the boundary layer. The total concentration of inorganic chlorine compounds found over marine regions was 1014 pptv and 609 pptv over continental regions with variability found to be driven by changes in meteorological conditions, particle liquid water content, particle pH, and proximity to large anthropogenic sources. However, displacement of particle chloride was often not a large enough source to fully explain the concentrations of gas phase Cly compounds. We use the GEOS-Chem global chemical transport model to simulate the emissions, gas-particle partitioning, and downwind transport and deposition of Cly during winter. Simulated concentrations of HCl, particle chloride, and other dominant Cly compounds are compared to measurements made during the WINTER aircraft campaign. The relative roles of Cly sources from sea-salt aerosol and anthropogenic sources such as power plants, biomass burning and road salt are explored.

A method of estimating log weights.

Science.gov (United States)

Charles N. Mann; Hilton H. Lysons

1972-01-01

This paper presents a practical method of estimating the weights of logs before they are yarded. Knowledge of log weights is required to achieve optimum loading of modern yarding equipment. Truckloads of logs are weighed and measured to obtain a local density index (pounds per cubic foot) for a species of logs. The density index is then used to estimate the weights of...

California-Nevada uranium logging. Final report

International Nuclear Information System (INIS)

1981-04-01

The purpose of this project was to obtain geophysical logs of industry drill holes to assess the uranium resource potential of geologic formations of interest. The work was part of the US Department of Energy's National Uranium Resource Evaluation (NURE) Program. The principal objective of the logging program was to determine radioelement grade of formations through natural gamma ray detectors. Supplementary information was obtained from resistivity (R), self-potential (SP), point resistance (RE), and neutron density (NN) logs for formation interpretation. Additional data for log interpretation was obtained from caliper logs, casing schedules, and downhole temperature. This data was obtained from well operators when available, with new logs obtained where not formerly available. This report contains a summary of the project and data obtained to date

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

Sulfonate activation of the electrophilic reactivity of chlorine and alkyl hypochlorides by the insertion of sulfur trioxide at the C1-C1 and O-C1 bonds. Addition of chlorine chloro- and ethoxysulfate to olefins

International Nuclear Information System (INIS)

Zefirov, N.S.; Koz'min, A.S.; Sorokin, V.D.; Zhdankin, V.V.

1986-01-01

At low temperatures (-40 to -80 0 C) sulfur trioxide enters the chlorine molecule (with the formation of chlorine chlorosulfate) and the ethyl hypochlorite molecule (giving chlorine ethoxysulfate). Both new compounds are highly reactive electrophilic chlorinating reagents and add to ethylene, activated alkenes (1-hexene and cyclohexene), and deactivated olefins (methyl methacrylate, tri- and tetrachloroethylene) in methylene chloride solution at low temperatures. The addition of chlorine chlorosulfate leads to the formation of β-chloroalkyl chlorosulfates with yields of 24-85%, and the addition of chlorine ethoxysulfate leads to β-chloroalkyl ethylsulfates with yields of 65-85%. The reactions with unsymmetrical olefins lead to mixtures of the regioisomers with a preference for the products from addition according to the Markovnikov rule; the addition to cyclohexene is trans-stereospecific. The investigated processes represent a new simple approach to the production of sulfate-activated chlorinating reagents and extend the possibilities for functional substitution of olefins

Robust Chemiresistive Sensor for Continuous Monitoring of Free Chlorine Using Graphene-like Carbon.

Science.gov (United States)

Aryasomayajula, Aditya; Wojnas, Caroline; Divigalpitiya, Ranjith; Selvaganapathy, Ponnambalam Ravi; Kruse, Peter

2018-02-23

Free chlorine is widely used in industry as a bleaching and oxidizing agent. Its concentration is tightly monitored to avoid environmental contamination and deleterious human health effects. Here, we demonstrate a solid state chemiresistive sensor using graphene like carbon (GLC) to detect free chlorine in water. A 15-20 nm thick GLC layer on a PET substrate was modified with a redox-active aniline oligomer (phenyl-capped aniline tetramer, PCAT) to increase sensitivity, improve selectivity, and impart fouling resistance. Both the bare GLC sensor and the PCAT-modified GLC sensor can detect free chlorine continuously and, unlike previous chemiresistive sensors, do not require a reset. The PCAT-modified sensor showed a linear response with a slope of 13.89 (mg/L) -1 to free chlorine concentrations between 0.2 and 0.8 mg/L which is relevant for free chlorine monitoring for drinking water and wastewater applications. The PCAT-modified GLC sensors were found to be selective and showed less than 0.5% change in current in response to species such as nitrates, phosphates and sulfates in water. They also were resistant to fouling from organic material and showed only a 2% loss in signal. Tap water samples from residential area were tested using this sensor which showed good agreement with standard colorimetric measurement methods. The GLC and PCAT-GLC sensors show high sensitivity and excellent selectivity to free chlorine and can be used for continuous automated monitoring of free chlorine.

[Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

Science.gov (United States)

Onodera, Sukeo

2010-09-01

This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

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.

Degradation of natural organic matter by UV/chlorine oxidation: Molecular decomposition, formation of oxidation byproducts and cytotoxicity.

Science.gov (United States)

Wang, Wen-Long; Zhang, Xue; Wu, Qian-Yuan; Du, Ye; Hu, Hong-Ying

2017-11-01

The degradation of natural organic matters (NOMs) by the combination of UV and chlorine (UV/chlorine) was investigated in this study. UV/chlorine oxidation can effectively degrade NOMs, with the degradation of chromophores (∼80%) and fluorophores (76.4-80.8%) being more efficient than that of DOC (15.1-18.6%). This effect was attributed to the chromophores and fluorophores (double bonds, aromatic groups and phenolic groups) being preferentially degraded by UV/chlorine oxidation, particularly reactive groups with high electron donating capacity. Radical species •OH and •Cl were generated during UV/chlorine oxidation, with the contribution of •OH 1.4 times as high as that of •Cl. The degradation kinetics of different molecular weight (MW) fractions suggests that UV/chlorine oxidation degrades high MW fractions into low MW fractions, with the degradation rates of high MW fractions (>3000 Da) 4.5 times of those of medium MW fractions (1000-3000 Da). In comparison with chlorination alone, UV/chlorine oxidation did not increase the formation (30 min) and formation potential (24 h) of trihalomethanes, but instead promoted the formation and formation potential of haloacetic acids and chloral hydrate. Adsorbable organic halogen (AOX) formed from UV/chlorine oxidation of NOM were 0.8 times higher than those formed from chlorination. Cytotoxicity studies indicated that the cytotoxicity of NOM increased after both chlorination and UV/chlorine oxidation, which may be due to the formation of AOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of Chlorinated Hydrocarbon Concentrations in Tehran’s Districts Drinking Water

Directory of Open Access Journals (Sweden)

Alireza Pardakhti

2012-01-01

Full Text Available In this study Tehran’s drinking water was evaluated for the presence of chlorinated hydrocarbons during spring and summer of 2009. Chlorinated hydrocarbons are an important class of environmental pollutants that cause adverse health effects on human’s kidney, liver and central nervous systems. In this study six water districts were selected for taking drinking water samples in the city of Tehran as well as one location outside the city limits. The samples were analyzed by GC/MS using EPA method 8260. The average concentrations of 1,1-dichloroethylene, 1,2 Dichloromethane, Tetra chloromethane, Trichloroethylene and tetra chloroethylene were determined during a 7 month period and the results were 0.04ppb, 0.52ppb, 0.01ppb, 0.24ppb, 0.03ppb respectively. The highest concentration of chlorinated hydrocarbon observed in Tehran’s drinking water was Trichloroethylene and the lowest concentration was Tetra chloromethane. Districts 5 and 6 showed the highest concentrations of chlorinated hydrocarbons in the city of Tehran.

Influence of nitrogen source on NDMA formation during chlorination of diuron.

Science.gov (United States)

Chen, Wei-Hsiang; Young, Thomas M

2009-07-01

N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N'-(3,4-dichlorophenyl)-N,N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitriteNDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface water and groundwater in nitrogen forms and concentrations and disinfection approaches suggest strategies to reduce NDMA formation should vary with drinking water source.

Kinetic investigation of the chlorine reduction reaction on electrochemically oxidised ruthenium

International Nuclear Information System (INIS)

Thomassen, M.; Karlsen, C.; Borresen, B.; Tunold, R.

2006-01-01

The rate and mechanism of the electroreduction of chlorine on electrooxidised ruthenium has been investigated with focus on the effect of solution pH. Current/potential curves for the reduction process in solutions with constant chloride concentration of 1.0 mol dm -3 and varying H + concentration have been obtained with the use of the rotating disk electrode technique (RDE). It was found that the chlorine reduction rate is highly inhibited in solutions with high H + concentrations and that it can be satisfactorily described by the Erenburg mechanism, previously suggested for the chlorine evolution on RuO 2 and RTO. The expression of the kinetic current as a function of chlorine and H + concentration was obtained by solving the elementary rate equations of the kinetic mechanism. The kinetic constants obtained from the correlation of the kinetic current expression to the experimental data were used to simulate the dependence of the surface coverages and elementary reaction rates on overpotential

Influence of Nitrogen Source on NDMA Formation during Chlorination of Diuron

Science.gov (United States)

Chen, Wei-Hsiang; Young, Thomas M.

2009-01-01

N-Nitrosodimethylamine (NDMA) is formed during chlorination of water containing the herbicide diuron (N′-(3,4-dichlorophenyl)-N, N-dimethylurea) but formation is greatly enhanced in the presence of ammonia (chloramination). Groundwater impacted by agricultural runoff may contain diuron and relatively high total nitrogen concentrations; this study examines the impact of the nitrogen form (ammonium, nitrite or nitrate) on NDMA formation during chlorination of such waters. NDMA formation during chlorination of diuron increased in the order nitrite diuron dose. Formation of dichloramine seemed to fully explain enhanced NDMA formation in the presence of ammonium. Nitrate unexpectedly enhanced nitrosation of diuron derivatives to form NDMA compared to the cases of no added nitrogen or nitrite addition. Nitrite addition is less effective because it consumes more chlorine and produces intermediates that react rapidly with diuron and its aromatic byproducts. Differences between surface and groundwater in nitrogen forms and concentrations and disinfection approaches, suggest strategies to reduce NDMA formation should vary with drinking water source. PMID:19457535

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Li, Jian; Ma, Li-yun; Xu, Li, E-mail: xulpharm@mails.tjmu.edu.cn

2016-07-05

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

Epidemiological evidence of carcinogenicity of chlorinated organics in drinking water.

Science.gov (United States)

Cantor, K P

1982-12-01

Concern has recently been voiced over possible chronic toxicity associated with chlorination of public drinking water supplies in the United States. This paper reviews the available evidence and the studies underway to further evaluate hypothesized associations between cancer risk and byproducts of chlorination. Preliminary data from measures of halogenated volatiles and personal exposure histories from respondents in a large epidemiologic study of bladder cancer are presented. These data support the use in epidemiologic studies of categorical measures of exposure and suggest that results from completed case-control studies, based on death certificates, may have underestimated the true risk of exposure to chlorination by-products. The current generation of studies which use a case-control interview design offer many advantages over earlier efforts to evaluate this issue.

Enhanced reductive dechlorination in clay till contaminated with chlorinated solvents

DEFF Research Database (Denmark)

Damgaard, Ida

Chlorinated solvents are among the most frequently found contaminants in groundwater. In fractured media, chlorinated ethenes and ethanes are transported downwards through preferential pathways with subsequent diffusion into the sediment matrix. Due to slow back diffusion it can serve as a long...... (direct push delivery, Gl. Kongevej). Degradation of chlorinated ethenes (and ethanes) in the clay till matrix and in embedded high permeability features was investigated by high resolution sampling of intact cores combined with groundwater sampling. An integrated approach using chemical analysis...... (hydraulic fracturing with gravitational injection and direct push delivery) were therefore tested in clay till by injection of amendment-comparable tracers to investigate the possibility to overcome diffusion limitations in the low permeability matrix. The study of hydraulic fracturing demonstrated...

Chlorination of zirconyte concentrate

International Nuclear Information System (INIS)

Costa, N.G.

1988-01-01

Chlorination experiments with zirconyte concentrate were carried out in order to study the effects of temperature, percentage of reducing agent and porosity on the gasification of ZrO 2 for 10 and 20 minutes of reaction. Factorial analysis was applied and the results indicated that temperature and percentage of reducing agent were the two only variables effecting the ZrO 2 gasification. (author) [pt

Inactivation of Escherichia coli O157:H7 in biofilm on food-contact surfaces by sequential treatments of aqueous chlorine dioxide and drying.

Science.gov (United States)

Bang, Jihyun; Hong, Ayoung; Kim, Hoikyung; Beuchat, Larry R; Rhee, Min Suk; Kim, Younghoon; Ryu, Jee-Hoon

2014-11-17

We investigated the efficacy of sequential treatments of aqueous chlorine and chlorine dioxide and drying in killing Escherichia coli O157:H7 in biofilms formed on stainless steel, glass, plastic, and wooden surfaces. Cells attached to and formed a biofilm on wooden surfaces at significantly (P ≤ 0.05) higher levels compared with other surface types. The lethal activities of sodium hypochlorite (NaOCl) and aqueous chlorine dioxide (ClO₂) against E. coli O157:H7 in a biofilm on various food-contact surfaces were compared. Chlorine dioxide generally showed greater lethal activity than NaOCl against E. coli O157:H7 in a biofilm on the same type of surface. The resistance of E. coli O157:H7 to both sanitizers increased in the order of wood>plastic>glass>stainless steel. The synergistic lethal effects of sequential ClO₂ and drying treatments on E. coli O157:H7 in a biofilm on wooden surfaces were evaluated. When wooden surfaces harboring E. coli O157:H7 biofilm were treated with ClO₂ (200 μg/ml, 10 min), rinsed with water, and subsequently dried at 43% relative humidity and 22 °C, the number of E. coli O157:H7 on the surface decreased by an additional 6.4 CFU/coupon within 6 h of drying. However, when the wooden surface was treated with water or NaOCl and dried under the same conditions, the pathogen decreased by only 0.4 or 1.0 log CFU/coupon, respectively, after 12 h of drying. This indicates that ClO₂ treatment of food-contact surfaces results in residual lethality to E. coli O157:H7 during the drying process. These observations will be useful when selecting an appropriate type of food-contact surfaces, determining a proper sanitizer for decontamination, and designing an effective sanitization program to eliminate E. coli O157:H7 on food-contact surfaces in food processing, distribution, and preparation environments. Copyright © 2014 Elsevier B.V. All rights reserved.

32 CFR 700.846 - Status of logs.

Science.gov (United States)

2010-07-01

... Officers Afloat § 700.846 Status of logs. The deck log, the engineering log, the compass record, the bearing hooks, the engineer's bell book, and any records generated by automated data logging equipment...

Thermal diffusion of chlorine in uranium dioxide

International Nuclear Information System (INIS)

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

2006-01-01

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

The role and function of chlorine in the preparation of high-ratio cake flour.

Science.gov (United States)

Gough, B M; Whitehouse, M E; Greenwood, C T

1978-01-01

The literature on the role of chlorine treatment of flour for use in high-ratio cake production is discussed in relation to current knowledge of cereal chemistry and cake technology. A brief perspective of the present use of chlorine in high-ratio cake flours is included. Investigations of the uptake of gaseous chlorine by flour and its distribution among and chemical action upon the major flour components (water, protein, lipid, and carbohydrate) are assessed. The physical effects of chlorination as demonstrated by experiments with batters and cakes and by physicochemical observations of flour and its fractions are also considered. The characteristics of the starch in flour appear to be critical in high-ratio cakes. Chlorine treatment modifies the gelatinization behavior of the starch granules yet does not change their gelatinization temperature not is there evidence of chemical attack upon the starch molecules. Therefore, it is suggested that chlorine effects the necessary changes in starch behavior by reacting with the noncarbohydrate surface contaminants on the granules. Alternative methods of improving high-ratio cake flours are mentioned, particularly heat-treatment processes.

Role of Dehalogenases in Aerobic Bacterial Degradation of Chlorinated Aromatic Compounds

Directory of Open Access Journals (Sweden)

Pankaj Kumar Arora

2014-01-01

Full Text Available This review was conducted to provide an overview of dehalogenases involved in aerobic biodegradation of chlorinated aromatic compounds. Additionally, biochemical and molecular characterization of hydrolytic, reductive, and oxygenolytic dehalogenases was reviewed. This review will increase our understanding of the process of dehalogenation of chlorinated aromatic compounds.

Chlorination and dechlorination rates in a forest soil — A combined modelling and experimental approach

Energy Technology Data Exchange (ETDEWEB)

Montelius, Malin, E-mail: malin.montelius@liu.se [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Svensson, Teresia [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Lourino-Cabana, Beatriz [EDF, Laboratoire National d' Hydraulique et Environnement, 78401 Chatou (France); Thiry, Yves [Andra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Bastviken, David [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden)

2016-06-01

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

Reagent-Free Quantification of Aqueous Free Chlorine via Electrical Readout of Colorimetrically Functionalized Pencil Lines.

Science.gov (United States)

Mohtasebi, Amirmasoud; Broomfield, Andrew D; Chowdhury, Tanzina; Selvaganapathy, P Ravi; Kruse, Peter

2017-06-21

Colorimetric methods are commonly used to quantify free chlorine in drinking water. However, these methods are not suitable for reagent-free, continuous, and autonomous applications. Here, we demonstrate how functionalization of a pencil-drawn film with phenyl-capped aniline tetramer (PCAT) can be used for quantitative electric readout of free chlorine concentrations. The functionalized film can be implemented in a simple fluidic device for continuous sensing of aqueous free chlorine concentrations. The sensor is selective to free chlorine and can undergo a reagent-free reset for further measurements. Our sensor is superior to electrochemical methods in that it does not require a reference electrode. It is capable of quantification of free chlorine in the range of 0.1-12 ppm with higher precision than colorimetric (absorptivity) methods. The interactions of PCAT with the pencil-drawn film upon exposure to hypochlorite were characterized spectroscopically. A previously reported detection mechanism relied on the measurement of a baseline shift to quantify free chlorine concentrations. The new method demonstrated here measures initial spike size upon exposure to free chlorine. It relies on a fast charge built up on the sensor film due to intermittent PCAT salt formation. It has the advantage of being significantly faster than the measurement of baseline shift, but it cannot be used to detect gradual changes in free chlorine concentration without the use of frequent reset pulses. The stability of PCAT was examined in the presence of free chlorine as a function of pH. While most ions commonly present in drinking water do not interfere with the free chlorine detection, other oxidants may contribute to the signal. Our sensor is easy to fabricate and robust, operates reagent-free, and has very low power requirements and is thus suitable for remote deployment.

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

KAUST Repository

Peters, Marjolein C. F. M.; Keuten, Maarten G. A.; Knezev, Aleksandra; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.; Rietveld, Luuk C.; de Kreuk, Merle K.

2017-01-01

Gram-negative. The dominant bacterial families with a relative abundance of ≥10% of the total (non-chlorinated and chlorinated) communities were Flavobacteriaceae (24–21%), Xanthomonadaceae (23–24%), Moraxellaceae (12–11%) and Pseudomonadaceae (10

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

International Nuclear Information System (INIS)

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

2001-01-01

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

Palm distributions for log Gaussian Cox processes

DEFF Research Database (Denmark)

Coeurjolly, Jean-Francois; Møller, Jesper; Waagepetersen, Rasmus Plenge

2017-01-01

This paper establishes a remarkable result regarding Palm distributions for a log Gaussian Cox process: the reduced Palm distribution for a log Gaussian Cox process is itself a log Gaussian Cox process that only differs from the original log Gaussian Cox process in the intensity function. This new...... result is used to study functional summaries for log Gaussian Cox processes....

Systematic logging utilizing a log sheet designed for drill core descriptions. An example in uranium exploration activities

International Nuclear Information System (INIS)

Sasao, Eiji; Tsuruta, Tadahiko; Iida, Yoshimasa

2000-01-01

We describe the log sheets used during uranium exploration activities for unconformity-related uranium deposits by JNC. The purpose of using the logging sheets is to standardize the objects which all geologists must observe and for data quality assurance. The log sheets are a three-part set describing basement lithology, sandstone lithology and geotechnics. We devised our own log sheets to describe both the sandstone and the underlying basement rock when we started exploration in Athabasca Basin, Canada. We modified the sheets to gain a better understanding of the geological features related to uranium mineralization, and made final improvements to satisfy required quality based on the criteria of descriptive objects and accuracy. Use of the log sheets resulted in effective performance of core logging and improvement in the display of data. (author)

Log-binomial models: exploring failed convergence.

Science.gov (United States)

Williamson, Tyler; Eliasziw, Misha; Fick, Gordon Hilton

2013-12-13

Relative risk is a summary metric that is commonly used in epidemiological investigations. Increasingly, epidemiologists are using log-binomial models to study the impact of a set of predictor variables on a single binary outcome, as they naturally offer relative risks. However, standard statistical software may report failed convergence when attempting to fit log-binomial models in certain settings. The methods that have been proposed in the literature for dealing with failed convergence use approximate solutions to avoid the issue. This research looks directly at the log-likelihood function for the simplest log-binomial model where failed convergence has been observed, a model with a single linear predictor with three levels. The possible causes of failed convergence are explored and potential solutions are presented for some cases. Among the principal causes is a failure of the fitting algorithm to converge despite the log-likelihood function having a single finite maximum. Despite these limitations, log-binomial models are a viable option for epidemiologists wishing to describe the relationship between a set of predictors and a binary outcome where relative risk is the desired summary measure. Epidemiologists are encouraged to continue to use log-binomial models and advocate for improvements to the fitting algorithms to promote the widespread use of log-binomial models.

Inhibition of lipopolysaccharide induced acute inflammation in lung by chlorination.

Science.gov (United States)

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

2016-02-13

Lipopolysaccharide (LPS, also called endotoxin) is a pro-inflammatory constituent of gram negative bacteria and cyanobacteria, which causes a potential health risk in the process of routine urban application of reclaimed water, such as car wash, irrigation, scenic water refilling, etc. Previous studies indicated that the common disinfection treatment, chlorination, has little effect on endotoxin activity removal measured by Limulus amebocyte lysate (LAL) assay. However, in this study, significant decrease of acute inflammatory effects was observed in mouse lung, while LAL assay still presented a moderate increase of endotoxin activity. To explore the possible mechanisms, the nuclear magnetic resonance (NMR) results showed the chlorination happened in alkyl chain of LPS molecules, which could affect the interaction between LPS and LPS-binding protein. Also the size of LPS aggregates was found to drop significantly after treatment, which could be another results of chlorination caused polarity change. In conclusion, our observation demonstrated that chlorination is effective to reduce the LPS induced inflammation in lung, and it is recommended to use health effect-based methods to assess risk removal of water treatment technologies. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of residual active chlorine in sodium hypochlorite solutions after dissolution of porcine incisor pulpal tissue.

Science.gov (United States)

Clarkson, R M; Smith, T K; Kidd, B A; Evans, G E; Moule, A J

2013-12-01

In previous studies, surfactant-containing Hypochlor brands of sodium hypochlorite showed better tissue solubilizing abilities than Milton; differences not explained by original active chlorine content or presence of surfactant. It was postulated that exhaustion of active chlorine content could explain differences. This study aimed to assess whether Milton's poorer performance was due to exhaustion of active chlorine. Parallel experiments assessed the influence of titration methods, and the presence of chlorates, on active chlorine measurements. Time required to dissolve one or groups of 10 samples of porcine incisor pulp samples in Milton was determined. Residual active chlorine was assessed by thermometric titration. Iodometric and thermometric titration was carried out on samples of Milton. Chlorate content was also measured. Dissolution of single and 10 pulp samples caused a mean loss of 1% and 3% respectively of active chlorine, not being proportional to tissue dissolved. Thermometric ammonium ion titration resulted in 10% lower values than iodometric titration. Chlorate accounted for much of this difference. Depletion of active chlorine is not the reason for differences in tissue dissolving capabilities of Milton. Thermometric ammonium ion titration gives more accurate measurement of active chlorine content than iodometric titration. © 2013 Australian Dental Association.

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

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Lucía I., E-mail: lbarbosa@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); González, Jorge A. [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina); Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, Parque General San Martín, CP M5502JMA Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI-CONICET), Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis, Chacabuco 17, CP 5700 San Luis (Argentina)

2015-04-10

Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl{sub 2} on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl{sub 2} at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl{sub 2}Si{sub 2}O{sub 8}, SiO{sub 2}, and CaSiO{sub 3}.

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

International Nuclear Information System (INIS)

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

1998-01-01

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

Application of Chlorine-Assisted Chemical Vapor Deposition of Diamond at Low Temperatures

Science.gov (United States)

Pan, Chenyu; Altemir, David A.; Margrave, John L.; Hauge, Robert H.

1994-01-01

Low temperature deposition of diamond has been achieved by a chlorine-assisted diamond chemical vapor deposition (CA-CVD) process. This method begins with the thermal dissociation of molecular chlorine into atomic chlorine in a resistively heated graphite furnace at temperatures between 1300 and 1500 deg. C. The atomic chlorine, upon mixing, subsequently reacts with molecular hydrogen and hydrocarbons. The rapid exchange reactions between the atomic chlorine, molecular hydrogen, and hydrocarbons give rise to the atomic hydrogen and carbon precursors required for diamond deposition. Homoepitaxial diamond growth on diamond substrates has been studied over the substrate temperature range of 100-950 C. It was found that the diamond growth rates are approximately 0.2 microns/hr in the temperature range between 102 and 300 C and that the growth rates do not decrease significantly with a decrease in substrate temperature. This is unique because the traditional diamond deposition using H2/CH4 systems usually disappears at substrate temperatures below approx. 500 deg. C. This opens up a possible route to the deposition of diamond on low-melting point materials such as aluminum and its alloys.

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

International Nuclear Information System (INIS)

Barbosa, Lucía I.; González, Jorge A.; Ruiz, María del Carmen

2015-01-01

Highlights: • β-Spodumene was roasted with calcium chloride to extract lithium. • The optimal conditions of the chlorination process are 900 °C and 120 min. • The products of the reaction are lithium chloride, anorthite, and silica. - Abstract: Chlorination roasting was used to extract lithium as lithium chloride from β-spodumene. The roasting was carried out in a fixed bed reactor using calcium chloride as chlorinating agent. The mineral was mixed with CaCl 2 on a molar ratio of 1:2. Reaction temperature and time were investigated. The reactants and roasted materials were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and atomic absorption spectrophotometry (AAS). The mineral starts to react with CaCl 2 at around 700 °C. The optimal conditions of lithium extraction were found to be 900 °C and 120 min of chlorination roasting, under which it is attained a conversion degree of 90.2%. The characterization results indicate that the major phases present in the chlorinating roasting residue are CaAl 2 Si 2 O 8 , SiO 2 , and CaSiO 3

Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment.

Science.gov (United States)

Adira Wan Khalit, Wan Nor; Tay, Kheng Soo

2016-05-18

Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination.

Differences in Field Effectiveness and Adoption between a Novel Automated Chlorination System and Household Manual Chlorination of Drinking Water in Dhaka, Bangladesh: A Randomized Controlled Trial

Science.gov (United States)

Pickering, Amy J.; Crider, Yoshika; Amin, Nuhu; Bauza, Valerie; Unicomb, Leanne; Davis, Jennifer; Luby, Stephen P.

2015-01-01

The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities. PMID:25734448

Differences in field effectiveness and adoption between a novel automated chlorination system and household manual chlorination of drinking water in Dhaka, Bangladesh: a randomized controlled trial.

Science.gov (United States)

Pickering, Amy J; Crider, Yoshika; Amin, Nuhu; Bauza, Valerie; Unicomb, Leanne; Davis, Jennifer; Luby, Stephen P

2015-01-01

The number of people served by networked systems that supply intermittent and contaminated drinking water is increasing. In these settings, centralized water treatment is ineffective, while household-level water treatment technologies have not been brought to scale. This study compares a novel low-cost technology designed to passively (automatically) dispense chlorine at shared handpumps with a household-level intervention providing water disinfection tablets (Aquatab), safe water storage containers, and behavior promotion. Twenty compounds were enrolled in Dhaka, Bangladesh, and randomly assigned to one of three groups: passive chlorinator, Aquatabs, or control. Over a 10-month intervention period, the mean percentage of households whose stored drinking water had detectable total chlorine was 75% in compounds with access to the passive chlorinator, 72% in compounds receiving Aquatabs, and 6% in control compounds. Both interventions also significantly improved microbial water quality. Aquatabs usage fell by 50% after behavioral promotion visits concluded, suggesting intensive promotion is necessary for sustained uptake. The study findings suggest high potential for an automated decentralized water treatment system to increase consistent access to clean water in low-income urban communities.

Chlorination and chloramination of aminophenols in aqueous solution: oxidant demand and by-product formation.

Science.gov (United States)

Mehrez, O Abou; Dossier-Berne, F; Legube, B

2015-01-01

Chlorination and monochloramination of aminophenols (AP) were carried out in aqueous solution at 25°C and at pH 8.5. Oxidant demand and disinfection by-product formation were determined in excess of oxidant. Experiments have shown that chlorine consumption of AP was 40-60% higher than monochloramine consumption. Compared with monochloramination, chlorination of AP formed more chloroform and haloacetic acids (HAA). Dichloroacetic acid was the major species of HAA. Chloroform and HAA represented, respectively, only 1-8% and 14-15% of adsorbable organic halides (AOX) by monochloramination but up to 29% and 39% of AOX by chlorination.

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.

Organochlorine compounds and the biogeochemical cycle of chlorine in soils: A review

Science.gov (United States)

Vodyanitskii, Yu. N.; Makarov, M. I.

2017-09-01

Chloride ions in soil may interact with soil organic matter and form organochlorine compounds in situ. The biotic chlorination of soil organic substances takes places under aerobic conditions with participation of H2O2 forming from peroxidases released by soil microorganisms (in particular, by microscopic fungi). The abiotic chlorination results also from the redox reactions with the participation of Fe3+/Fe2+ system, but it develops several times slower. Chlorination of soil organic substances is favored by Cl- coming to soil both from natural (salinized soil-forming rocks and groundwater, sea salt) and anthropogenic sources of chlorides, i.e., spills of saline water at oil production, road deicing chemicals, mineral fertilizers, etc. The study of the biogeochemical chlorine cycle should take into account the presence of organochlorine compounds in soils, in addition to transformation and migration of chloride ions.

Methylated silicates may explain the release of chlorinated methane from Martian soil

Science.gov (United States)

Bak, Ebbe N.; Jensen, Svend J. Knak; Nørnberg, Per; Finster, Kai

2016-01-01

The only organic compounds that have been detected in the Martian soil are simple chlorinated compounds released from heated surface material. However, the sources of the organic carbon are in dispute. Wind abraded silicates, which are widespread on the Martian surface, can sequester atmospheric methane which generates methylated silicates and thus could provide a mechanism for accumulation of reduced carbon in the surface soil. In this study we show that thermal volatilization of methylated silicates in the presence of perchlorate leads to the production of chlorinated methane. Thus, methylated silicates could be a source of the organic carbon released as chlorinated methane upon thermal volatilization of Martian soil samples. Further, our experiments show that the ratio of the different chlorinated compounds produced is dependent on the mass ratio of perchlorate to organic carbon in the soil.

Comparative analysis of nuclear magnetic resonance well logging and nuclear magnetic resonance mud logging

International Nuclear Information System (INIS)

Yuan Zugui

2008-01-01

The hydrogen atoms in oil and water are able to resonate and generate signals in the magnetic field, which is used by the NMR (nuclear magnetic resonance) technology in petroleum engineering to research and evaluate rock characteristics. NMR well logging was used to measure the physical property parameters of the strata in well bore, whereas NMR mud logging was used to analyze (while drilling) the physical property parameters of cores, cuttings and sidewall coring samples on surface (drilling site). Based on the comparative analysis of the porosity and permeability parameters obtained by NMR well logging and those from analysis of the cores, cuttings and sidewall coring samples by NMR mud logging in the same depth of 13 wells, these two methods are of certain difference, but their integral tendency is relatively good. (authors)

Clean Bleaching Engineering Practice for Bagasse Pulp: Totally Chlorine-Free and Elemental Chlorine-Free Bleaching Realized with the Same Production Line

Directory of Open Access Journals (Sweden)

Zhi Li

2015-03-01

Full Text Available The experimental research, process design principles, and engineering practice of a bagasse pulp production line that could run both totally chlorine-free (OPQ(PO and elemental chlorine-free (OPD(EOP bleaching sequences are discussed in this paper. Under specified process conditions, the oxygen delignification rate was up to 50% and the brightness of unbleached pulp increased. The (OPQ(PO sequence bleached pulp had a brightness of 83.1% ISO and an intrinsic viscosity of 888 mL/g, and the (OPD(EOP sequence bleached pulp had a brightness of 85.7% ISO and an intrinsic viscosity of 905 mL/g. Pulp quality produced from both bleaching sequences was better than pulp bleached by the chlorination, alkaline extraction, and hypochlorite (CEH sequence. The wastewater was discharged only from the Q or D stage, and the chemical oxygen demand (COD of Q or D stage was about 650 mg/L or 1100 mg/L, respectively. It was easy to alternate between these two bleaching sequences, and the bleached pulp quality from these sequences was stable.

DOE-Grand Junction logging model data synopsis

International Nuclear Information System (INIS)

Mathews, M.A.; Koizumi, C.J.; Evans, H.B.

1978-05-01

This synopsis provides the available data concerning the logging models at the DoE-Grand Junction facility, to date (1976). Because gamma-ray logs are used in uranium exploration to estimate the grade (percent U 3 O 8 ) and the thickness of uranium ore zones in exploration drill holes, logging models are required to calibrate the gamma-ray logging equipment in order to obtain accuracy, uniformity, standardization, and repeatability during logging. This quality control is essential for accurate ore reserve calculations and for estimates of ore potential. The logging models at the DoE-Grand Junction facility are available for use by private industry in calibrating their gamma-ray logging equipment. 21 figures, 26 tables

SNG-logs at Skjern

DEFF Research Database (Denmark)

Korsbech, Uffe C C; Petersen, Jesper; Aage, Helle Karina

1998-01-01

Spectral Natural Gamma-ray logs have been run in two water supply borings at Skjern. The log data have been examined by a new technique - Noise Adjusted Singular Value Decomposition - in order to get a detailed and reliable picture of the distribution of uranium and thorium gamma-rays from heavy...

Comprehensive Model for Enhanced Biodegradation of Chlorinated Solvents in Groundwater

Science.gov (United States)

Kouznetsova, I.; Gerhard, J. I.; Mao, X.; Robinson, C.; Barry, A. D.; Harkness, M.; Mack, E. E.; Dworatzek, S.

2007-12-01

SABRE (Source Area BioREmediation) is a public/private consortium whose charter is to de-termine if enhanced anaerobic bioremediation can result in effective treatment of chlorinated solvent DNAPL source areas. The focus of this 4-year, $5.7 million research and development project is a field site in the United Kingdom containing TCE DNAPL. A comprehensive numerical model for simulating dehalogenation of chlorinated ethenes has been developed. The model considers the kinetic dissolution of DNAPL and nonaqueous organic amendments, bacterial growth and decay, and the interaction of biological and geochemical reactions that might influence biological activity. The model accounts for inhibitory effects of high chlorin-ated solvent concentrations as well as the link between fermentation and dehalogenation due to dynamic hydrogen concentration (the direct electron donor). In addition to the standard biodegradation pathways, sulphate reduction, mineral dissolution and precipitation kinetics are incorporated. These latter processes influence the soil buffering capacity and thus the net acidity generated. One-dimensional simulations were carried out to reproduce the data from columns packed with site soil and groundwater exhibiting both intermediate (250 mg/L) and near solubility (1100 mg/L) TCE concentrations. The modelling aims were to evaluate the key processes underpinning bioremediation success and provide a tool for investigating field sys-tem sensitivity to site data and design variables. This paper will present the model basis and validation and examine sensitivity to key processes including chlorinated ethene partitioning into soybean oil, sulphate reduction, and geochemical influences such as pH and the role of buffering in highly dechlorinating systems.

Chlorinated paraffins wrapping of carbon nanotubes: A theoretical investigation

Science.gov (United States)

Ding, Qiuyue; Ding, Ning; Chen, Xiangfeng; Wu, Chi-Man Lawrence

2018-04-01

How nanomaterials interact with pollutants is the central for understanding their environmental behavior and practical application. In this work, molecular dynamics (MD) and density functional theoretical (DFT) methods were used to investigated the influence of carbon chain length, degree of chlorination, chain configuration, and chirality of chlorinated paraffin (CP) and diameter of single-walled carbon nanotubes (SWNTs) on the interaction between CPs and SWNTs. The simulation results demonstrated that CP chain length and chlorination degree played considerably important roles in determining interaction strength between SWNTs and CPs. The interaction energies increased with increasing chain length and chlorination degree. The chirality of SWNT exerted negligible influence on the interaction energy between SWNTs and CPs. On the contrary, interaction energy increased with increasing radius of SWNTs due to the surface curvatures. This result was rationalized by considering the decrease in SWNT curvature with increasing radius, which resulted in plane-like CNT wall. The negligible influence of CP chain configurations was attributed to relative flexibility of CP carbon chains, which can wrap on tubes through conformational changes with low-energy barriers. MD results indicated that CPs could adsorb on SWNT surface rapidly in aqueous environment. Charge transfer and electronic density results indicated that the interaction between CPs and SWNTs was physisorption in nature. This work provides fundamental information regarding SWNTs as sorbents for CPs extraction and adsorptive removal from environmental water system.

Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

Science.gov (United States)

Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

2011-01-01

High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

Tools for Management of Chlorinated Solvent - Contaminated Sites

Science.gov (United States)

2009-12-03

Movie Lee Ann Doner – (2008) MS CSU “Sandy aquifers” Image from Fred Payne /ARCADIS New Paradigm After NRC 2005 l~r SERDP. Advancing solvent plume...Situ Bioremediation Using Emulsified  Edible  Oil”   AFCEE (http://www.afcee.brooks.af.mil/products/techtrans/) - “Principles and Practices of Enhanced...Anaerobic Bioremediation of  Chlorinated Solvents”  - “Protocol for In Situ Bioremediation of Chlorinated Solvents Using  Edible  Oil” 232 Short Course

Pepspectives of chlorine application in metallurgy of vanadium

International Nuclear Information System (INIS)

Korshunov, B.G.; Kutsenko, S.A.

1983-01-01

The most expedient variants of reprocessing of vanadium technical oxide (5), ferrovanadium and converter slags by chlorine technology with production of pure metal are considered. It is shown that production of vanadium by the way of electro- or metallothermal reduction of chlorides provides more plastic metal in comparison with reduction from oxides. The methods of production of VOCl 3 , VCl 4 and vanadium lowest chlorides are considered. Necessity of expansion of production of vanadium chlorine derivatives is dictated as well by their increasing application in different areas of national economy, in particular, as catalysts in organic synthesis

Influence of borehole-eccentred tools on wireline and logging-while-drilling sonic logging measurements

KAUST Repository

Pardo, David; Matuszyk, Paweł Jerzy; Torres-Verdí n, Carlos; Mora Cordova, Angel; Muga, Ignacio; Calo, Victor M.

2013-01-01

We describe a numerical study to quantify the influence of tool-eccentricity on wireline (WL) and logging-while-drilling (LWD) sonic logging measurements. Simulations are performed with a height-polynomial-adaptive (hp) Fourier finite-element method

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

International Nuclear Information System (INIS)

Sakamura, Yoshiharu; Inoue, Tadashi; Iwai, Takashi; Moriyama, Hirotake

2001-01-01

A new chlorination method using ZrCl 4 , which has a high reactivity with oxygen, has been investigated for more efficient oxide treatment. After actinide oxides are chlorinated and dissolved in a molten salt bath, actinide metals can be selectively collected using the electrorefining process. This process is well suited for pyrochemical reprocessing of metallic fuels. In LiCl-KCI eutectic melts, rare-earth oxides (Y 2 O 3 , La 2 O 3 , CeO 2 , and Nd 2 O 3 ) and actinide oxides (UO 2 and PuO 2 ) were chlorinated by adding ZrCl 4 . As a result, rare-earth and actinide elements were dissolved into the salt as trivalent ions and ZrO 2 was precipitated. When an excess of ZrCI 4 was added, oxides in powder form were completely chlorinated in five hours. It was demonstrated that the ZrCI 4 chlorination method, free from corrosive gas such as chlorine, was very simple and useful. (author)

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...

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

NARCIS (Netherlands)

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

2001-01-01

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

Pulse radiolysis investigations on the oxidation of bilirubin by chlorinated peroxyl radicals (Preprint No. RC.18)

International Nuclear Information System (INIS)

Mohan, Hari; Gopinathan, C.

1989-01-01

Chlorinated peroxyl radicals were observed to oxidize bilirubin. The rate constants, estimated from the formation kinetics of bilirubin cation, were observed to decrease with decrease in the chlorine substitution of various chlorinated peroxyl radicals. (author)

Elaboration in the area of low temperature chlorination of rare-metal crude ore

International Nuclear Information System (INIS)

Mirsaidov, U.M.

2002-01-01

The chemical base of low temperature chlorination of rare-metal crude ore was elaborated. The chemical nature of chlorination process which pass at low temperature was decoded and scientifically elaborated

Nuclear well logging in hydrology

International Nuclear Information System (INIS)

1971-01-01

The optimum development of regional and local groundwater resources requires a quantitative evaluation of its aquifers and aquicludes, and of the physical and chemical properties relevant to the recharge to and withdrawal of water from them. If an understanding of the groundwater regime is to be obtained, geological observations at outcrop must be augmented by subsurface measurements of the strata and the waters they contain. Measurements of many hydrological and geological parameters can be made in situ by nuclear geophysical well-logging methods. Very simply, well logging consists of lowering a measuring probe into a well and making a continuous record of the variations of a particular parameter with depth. In most circumstances, repetition of the measurements under differing hydrodynamic conditions results in a better definition of the flow regime in the aquifer. Nuclear well-logging techniques have for some years been capable of solving a number of the sub-surface measurement problems faced by hydrogeologists. However, the present usage of these methods varies from country to country and the literature concerning applications is scattered in the professional journals of several disciplines. The objective of this report is to include in a single reference volume descriptions of the physical principles of nuclear logging methods, their applications to hydrogeological problems and their limitations on a level suitable for the practising hydrologists with a limited knowledge of nuclear physics. The Working Group responsible for compiling the report recommended that it should cover a broad spectrum of hydrogeological investigations and problems. For example, it saw no valid reason to distinguish for the purposes of the report between well-logging applications for water-supply purposes and for water-flooding studies in the petroleum industry. Neutron measurements made for soil-moisture determinations in the unsaturated zone have been specifically omitted, however, as

A Universal Logging System for LHCb Online

International Nuclear Information System (INIS)

Nikolaidis, Fotis; Brarda, Loic; Garnier, Jean-Christophe; Neufeld, Niko

2011-01-01

A log is recording of system's activity, aimed to help system administrator to traceback an attack, find the causes of a malfunction and generally with troubleshooting. The fact that logs are the only information an administrator may have for an incident, makes logging system a crucial part of an IT infrastructure. In large scale infrastructures, such as LHCb Online, where quite a few GB of logs are produced daily, it is impossible for a human to review all of these logs. Moreover, a great percentage of them as just n oise . That makes clear that a more automated and sophisticated approach is needed. In this paper, we present a low-cost centralized logging system which allow us to do in-depth analysis of every log.

Model wells for nuclear well logging

International Nuclear Information System (INIS)

Tittle, C.W.

1989-01-01

Considerations needed in the design and construction of model wells for nuclear log calibration are covered, with special attention to neutron porosity logging and total γ-ray logging. Pulsed neutron decay-time and spectral γ-ray logging are discussed briefly. The American Petroleum Institute calibration facility for nuclear logs is a good starting point for similar or expanded facilities. A few of its shortcomings are mentioned; they are minor. The problem of fluid saturation is emphasized. Attention is given to models made of consolidated rock and those containing unconsolidated material such as Ottawa sand. Needed precautions are listed. A similarity method is presented for estimating the porosity index of formations that are not fully saturated. (author)

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.

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...

Chlorine toxicity to copepods: implications in the context of zooplankton entrainment in power plants

International Nuclear Information System (INIS)

Ershath, M.; Altaff, K.; Sriyutha Murthy, P.; Venugopalan, V.P.

2008-01-01

Full text: Experiments were conducted to assess the effects of chlorine on zooplankton, such as those entrained into cooling water circuits of power stations. Three copepod groups (Calanoida, Cyclopoida and Harpacticoida) and copepod naupliar stages were chosen for the study. Percentage mortality of the different groups of copepods and the naupliar stages was assessed after 5, 15, 30, 45 and 60 min of exposure to chlorine residuals of 0.2, 0.5, 0.8 and 1.0 mg/1. Mortality increased with increase in exposure time and concentration of the biocide. Calanoids were relatively more tolerant to chlorine compared to the other groups. Chlorine toxicity may be classified (from more tolerant to less tolerant) as calanoids > cyclopoida > harpacticoids > naupliar stages. Continuous chlorination (with total chlorine residuals of 0.1 - 0.3 mg/l at the discharge) is the general practice adopted in tropical power stations. Considering this, results of the present study indicate and expected percentage mortality of the different groups as: calanoids - 7.9%, cyclopoids - 11.1%, harpacticoids - 10.2% and naupliar stages - 21.6%. However, the data need to be verified under actual plant conditions. (author)

Detection of chlorine in water

Czech Academy of Sciences Publication Activity Database

Kašík, Ivan; Mrázek, Jan; Podrazký, Ondřej; Seidl, Miroslav; Aubrecht, Jan; Tobiška, Petr; Pospíšilová, Marie; Matějec, Vlastimil; Kovács, B.; Markovics, A.; Szili, M.

2009-01-01

Roč. 139, č. 1 (2009), s. 139-142 ISSN 0925-4005 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GA102/05/0948 Institutional research plan: CEZ:AV0Z20670512 Keywords : optical fiber sensor * chlorine Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.083, year: 2009

Artificial intelligence approach to interwell log correlation

Energy Technology Data Exchange (ETDEWEB)

Lim, Jong-Se [Korea Maritime University, Pusan(Korea); Kang, Joo Myung [Seoul National University, Seoul(Korea); Kim, Jung Whan [Korea National Oil Corp., Anyang(Korea)

2000-04-30

This paper describes a new approach to automated interwell log correlation using artificial intelligence and principal component analysis. The approach to correlate wire line logging data is on the basis of a large set of subjective rules that are intended to represent human logical processes. The data processed are mainly the qualitative information such as the characteristics of the shapes extracted along log traces. The apparent geologic zones are identified by pattern recognition for the specific characteristics of log trace collected as a set of objects by object oriented programming. The correlation of zones between wells is made by rule-based inference program. The reliable correlation can be established from the first principal component logs derived from both the important information around well bore and the largest common part of variances of all available well log data. Correlation with field log data shows that this approach can make interwell log correlation more reliable and accurate. (author). 6 refs., 7 figs.