Sample records for chlorates

  1. Chlorate: a reversible inhibitor of proteoglycan sulfation

    Energy Technology Data Exchange (ETDEWEB)

    Humphries, D.E.; Silbert, J.E.


    Bovine aorta endothelial cells were cultured in medium containing (/sup 3/H)glucosamine, (/sup 35/S)sulfate, and various concentrations of chlorate. Cell growth was not affected by 10 mM chlorate, while 30 mM chlorate had a slight inhibitory effect. Chlorate concentrations greater than 10 mM resulted in significant undersulfation of chondroitin. With 30 mM chlorate, sulfation of chondroitin was reduced to 10% and heparan to 35% of controls, but (/sup 3/H)glucosamine incorporation on a per cell basis did not appear to be inhibited. Removal of chlorate from the culture medium of cells resulted in the rapid resumption of sulfation.

  2. Chlorate analyses in matrices of animal origin (United States)

    Sodium chlorate is being developed as a potential food-safety tool for use in the livestock industry because of its effectiveness at decreasing concentrations of certain Gram-negative pathogens in gastrointestinal tracts of food animals. A number of studies with sodium chlorate in animals have demon...

  3. Current efficiency in the chlorate cell process

    Directory of Open Access Journals (Sweden)

    Spasojević Miroslav D.


    Full Text Available A mathematical model has been set up for current efficiency in a chlorate cell acting as an ideal electrochemical tubular reactor with a linear increase in hypochlorite concentration from the entrance to the exit. Good agreement was found between the results on current efficiency experimentally obtained under simulated industrial chlorate production conditions and the theoretical values provided by the mathematical model. [Projekat Ministarstva nauke Republike Srbije, br. 172057 i br. 172062

  4. 46 CFR 153.1065 - Sodium chlorate solutions. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Sodium chlorate solutions. 153.1065 Section 153.1065... Procedures § 153.1065 Sodium chlorate solutions. (a) No person may load sodium chlorate solutions into a... solutions are immediately washed away. Approval of Surveyors and Handling of Categories A, B, C, and D...

  5. Kinetics and disposition of orally dosed sodium chlorate in sheep (United States)

    Experiments were conducted in sheep to determine excretory characteristics of sodium chlorate after a single oral dose. In Exp. 1 lambs (n = 16; age = 8.1 ± 1.7 d; BW = 8.2 ± 1.1 kg; mean ± SD) were dosed orally with 0, 30, 60, or 90 mg/kg BW of sodium chlorate. Twenty-four h after exposure chlorate...

  6. Microbial (per)chlorate reduction in hot subsurface environments

    NARCIS (Netherlands)

    Liebensteiner, M.



    The microbial reduction of chlorate and perchlorate has been known for long as a respiratory process of mesophilic bacteria that thrive in diverse environments such as soils, marine and freshwater sediments. Chlorate and perchlorate are found in nature deriving from anthropogenic and


    Institute of Scientific and Technical Information of China (English)

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


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


    Institute of Scientific and Technical Information of China (English)

    Byung-HoYoon; Li-JunWangI; Se-JongKim


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

  9. Chlorate Concentration in the Jejunum and Cecum in Growing Pigs when Supplemented in Drinking Water (United States)

    Prior research has demonstrated that oral administration of chlorate and nitrate results in reduced risk and / or concentration of Salmonella enterica fecal shedding of infected pigs, poultry and ruminants. The effect of chlorate is concentration dependent in vitro, but the concentrations of chlorat...

  10. Ubiquity and diversity of dissimilatory (per)chlorate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Coates, J.D.; Michaelidou, U.; Bruce, R.A.; O' Connor, S.M.; Crespi, J.N.; Achenbach, L.A.


    Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per) chlorate, the authors enumerated the (per) chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 x 10{sup 3} to 2.4 x 10{sup 6} cells per g of sample. In addition, the authors isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per) chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per) chlorate, into chloride and molecular oxygen.

  11. Analytical Method for the Determination of Chlorate in Animal Matrices (United States)

    Contamination of meat products with gram-negative enteric pathogens contribute to over 1.5 million food borne illnesses each year. Recent studies have demonstrated 2-3 log unit reductions in numbers of E. coli O157:H7 and(or) Salmonella in food animals dosed with an experimental chlorate-containing ...

  12. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures. (United States)

    Oliver, Christy E; Beier, Ross C; Hume, Michael E; Horrocks, Shane M; Casey, Thomas A; Caton, Joel S; Nisbet, David J; Smith, David J; Krueger, Nathan A; Anderson, Robin C


    Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by

  13. Invited review: Efficacy, metabolism, and toxic responses to chlorate salts in food and laboratory animals. (United States)

    Smith, D J; Oliver, C E; Taylor, J B; Anderson, R C


    For over 100 yr, scientists have explored uses of sodium chlorate in agricultural applications. Sodium chlorate is a strong oxidizer, and thus can be very hazardous when not handled accordingly. Nevertheless, late 19th century agriculturists and scientists attempted to exploit the chemical properties of sodium chlorate as an herbicide and food preservative. It is the herbicidal utility that led to subsequent use of sodium chlorate in the agricultural industry since then. However, in 2000, USDA-ARS scientists proposed a new and targeted use of sodium chlorate against enterobacteria in food animal production. Specifically, when orally dosed in to cattle (Bos taurus), swine (Sus scrofa), broilers (Gallus gallus), turkeys (Meleagris gallopavo), and sheep (Ovis aries), chlorate reduced the fecal shedding of common enteropathogens of the Enterobacteriaceae family. Subsequent to this discovery, the efficacy of chlorate salts has been demonstrated in numerous production classes within species. Doses of sodium chlorate as low as 30 mg/kg BW, but typically 50 to 150 mg/kg BW, have been used to demonstrate efficacy against pathogens. Single or short-duration (food animals. In all species studied to date, the major biotransformation product of chlorate is chloride ion; chlorite is not present in tissues or excreta of chlorate dosed animals. Chlorate is rapidly eliminated in ruminants and nonruminants, primarily in urine; likewise, residual chlorate in tissues depletes rapidly. Application of any new chemical entity to food animal production carries with it a responsibility to understand adverse reactions that intended and nonintended exposures may have in target and (or) nontarget animals and an understanding of the pathways of elimination that occur after exposure. Therefore, the purpose of this review is to summarize the published data regarding the efficacy, metabolism, and toxicology of chlorate salts in target (livestock) and nontarget species.

  14. Efficacy, metabolism, and toxic responses to chlorate salts in food and laboratory animals (United States)

    For over 100 years, scientists have explored uses of sodium chlorate in agricultural applications. Sodium chlorate is a strong oxidizer, and thus can be very hazardous when not handled accordingly. Nevertheless, late 19th century agriculturists and scientists attempted to exploit the chemical proper...

  15. Chlorate reduction in the brine circuit of a chlor-alkali electrolysis. Chlorat-Reduktion im Solekreislauf einer Chlor-Alkali-Elektrolyse

    Energy Technology Data Exchange (ETDEWEB)

    Rodermund, R.


    The influence of reactant concentrations and temperature on the rate and selectivity of the chlorate/hydrochloric acid reaction was determined experimentally. A model equation system was derived on the basis of a reaction mechanism describing the reaction between chlorate and hydrochloric acid at high H/sup +/ and Cl/sup -/ concentrations in the temperature range between 40 and 90/sup 0/C. The reaction of chlorate and hydrochloric acid was found to be sufficient to maintain a low chlorate level in the brine circuit of a chlor-alkali electrolysis. ClO/sub 2/ formation is negligible if suitable reaction conditions are chosen. Further, a model equation based on Henry's law was established for the solubility of ClO/sub 2/ in mixed solutions of HCl and NaCl in the temperature range of 40 to 90/sup 0/C.

  16. Minimising chlorate in the electrolytic disinfection of irrigation water

    Directory of Open Access Journals (Sweden)

    Ingo Schuch


    Full Text Available Die Minimierung von Chlorat bei der elektrolytischen Gießwasserdesinfektion ist aufgrund problematischer Chloratrückstände in pflanzlichen Lebensmitteln von Bedeutung. Im Hinblick auf verfahrenstechnische Optimierungsvorschläge wurde daher am Beispiel einer Salzelektrolyseanlage (Einkammersystem geprüft, wie viel Chlorat beim Herstellungsprozess des Desinfektionsmittels entsteht und wie sich dessen Anteil bei einer Lagerung unter warmen Temperaturbedingungen im Gewächshaus verändert. Zudem wurde untersucht, wie sich der Pflanzendünger Ammonium auf das Desinfektionsmittel auswirkt. Dabei ergab sich, dass die Chloratbildung durch eine Kühlung des Elektrolysereaktors sowie des Desinfektionsmitteltanks und durch ein zur Kurzzeitlagerung ausgelegtes Bevorratungssystem von Desinfektionsmittel minimiert werden könnte. Ferner wurde bestätigt, dass Ammonium den Desinfektionsmittelverbrauch bzw. Chlorateintrag deutlich erhöht. Daher empfiehlt sich eine sensorbasierte Dosierung, um sich ändernde chemische Vorgänge im Gießwasser (Chlorzehrung zu berücksichtigen.

  17. Why chlorate occurs in potable water and processed foods: a critical assessment and challenges faced by the food industry. (United States)

    Kettlitz, Beate; Kemendi, Gabriella; Thorgrimsson, Nigel; Cattoor, Nele; Verzegnassi, Ludovica; Le Bail-Collet, Yves; Maphosa, Farai; Perrichet, Aurélie; Christall, Birgit; Stadler, Richard H


    Recently, reports have been published on the occurrence of chlorate mainly in fruits and vegetables. Chlorate is a by-product of chlorinating agents used to disinfect water, and can be expected to be found in varying concentrations in drinking water. Data on potable water taken at 39 sampling points across Europe showed chlorate to range from foods of 0.01 mg kg(-1). This default MRL has now led to significant problems in the EU, where routinely disinfected water, used in the preparation of food products such as vegetables or fruits, leaves chlorate residues in excess of the default MRL, and in strict legal terms renders the food unmarketable. Due to the paucity of data on the chlorate content of prepared foods in general, we collated chlorate data on more than 3400 samples of mainly prepared foods, including dairy products, meats, fruits, vegetables and different food ingredients/additives. In total, 50.5% of the food samples contained chlorate above 0.01 mg kg(-1), albeit not due to the use of chlorate as a pesticide but mainly due to the occurrence of chlorate as an unavoidable disinfectant by-product. A further entry point of chlorate into foods may be via additives/ingredients that may contain chlorate as a by-product of the manufacturing process (e.g. electrolysis). Of the positive samples in this study, 22.4% revealed chlorate above 0.1 mg kg(-1). In the absence of EU levels for chlorate in water, any future EU regulations must consider the already available WHO guideline value of 0.7 mg l(-1) in potable water, and the continued importance of the usage of oxyhalides for disinfection purposes.

  18. Fe-Mo alloy coatings as cathodes in chlorate production process

    Directory of Open Access Journals (Sweden)

    Gajić-Krstajić Ljiljana M.


    Full Text Available The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI, with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER. The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4. The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %. However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95% than in the pure dichromate buffering solution (97.5%.

  19. Continuous, low-dose oral exposure to sodium chlorate reduces fecal Enterobacteriaceae coliforms in sheep feces without inducing subclinical chlorate toxicosis (United States)

    Our objectives were to determine a minimal daily dose of sodium chlorate, to be included in the drinking water for 5 days, that is safe yet maintains efficacy in reducing fecal shedding of Escherichia coli in mature ewes. In a complete randomized experimental design, 25 Targhee ewes (age = 18- to 20...

  20. Evaluation of an experimental sodium chlorate product, with and without nitroethane, on Salmonella in cull dairy cattle (United States)

    Ruminant animals are natural reservoirs for Salmonella. These bacteria can reduce nitrate to nitrite through the membrane bound enzyme nitrate reductase which also has the ability to reduce chlorate to the cytotoxic end-product chlorite. An experimental product containing sodium chlorate (ECP) has...

  1. Foliar fertilization as an alternative to hand thinning fruit in chlorate treated Dimocarpus longan Lour. trees in Hawaii. (United States)

    Longan, Dimocarpus longan Lour, is a member of the Sapindaceae, a family that also includes lychee, and rambutan. The discovery of potassium chlorate (KClO3) induced flowering solved the problem of alternate bearing and enabled the grower to produce off-season longan. Chlorate treatments commonly i...

  2. Pressure and temperature dependence of the chlorine NQR in caesium and sodium chlorates. (United States)

    Ramesh, K P; Suresh, K S; Raghavendra Rao, C; Ramakrishna, J


    The (35)Cl nuclear quadrupole resonance (NQR) frequencies (nu(Q)) in caesium and sodium chlorates were measured as a function of temperature, from 77 to 300 K at different pressures up to 5.1 kbar, and the data were analysed to estimate the volume dependence of the electric field gradient (EFG), torsional frequency and also the contributions to the NQR frequency from static and dynamic effects. The variation of spin-lattice relaxation time with pressure at different temperatures was studied in the case of sodium chlorate and at room temperature in case of caesium chlorate. The pressure dependence of the spin-lattice relaxation time (T(1)) suggests that the relaxation is mainly due to the torsional motions.

  3. Influence of drinking water treatments on chlorine dioxide consumption and chlorite/chlorate formation. (United States)

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


    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%.

  4. Physiological and phylogenetic characterization of a stable chlorate-reducing benzene-degrading microbial community

    NARCIS (Netherlands)

    Weelink, S.A.B.; Tan, N.C.G.; Broeke, ten H.; Doesburg, van W.C.J.; Langenhoff, A.A.M.; Gerritse, J.; Stams, A.J.M.


    stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20¿1650 times higher than reported for anaerobic benzene degradation

  5. Control of sodium chlorate content in brine%盐水中氯酸钠含量的控银

    Institute of Scientific and Technical Information of China (English)

    韩飞; 张晓龙


    The source, hazards and control of sodium chlorate concentration in brine system were introduced. In order to ensure the decomposition efficiency of sodium chlorate and security of operation, the operation of chlorate decomposition and some notes were put%介绍了氯碱生产中盐水系统中氯酸钠的来源、危害及浓度的控制方法。为了保证氯酸钠的分解效率和操作安全性,对氯酸盐分解单元的操作及注意事项提出了建议。

  6. Contribution of tap water to chlorate and perchlorate intake: a market basket study. (United States)

    Asami, Mari; Yoshida, Nobue; Kosaka, Koji; Ohno, Koichi; Matsui, Yoshihiko


    The contributions of water to total levels of chlorate and perchlorate intake were determined using food and water samples from a market basket study from 10 locations in Japan between 2008 and 2009. Foods were categorized into 13 groups and analyzed along with tap water. The average total chlorate intake was 333 (min. 193-max. 486) μg/day for samples cooked with tap water. The contribution of tap water to total chlorate intake was as high as 47%-58%, although total chlorate intake was less than 32% of the tolerable daily intake, 1500 μg/day for body weight of 50 kg. For perchlorate, daily intake from water was 0.7 (0.1-4.4) μg/day, which is not high compared to the average total intake of 14 (2.5-84) μg/day, while the reference dose (RfD) is 35 μg/day and the provisional maximum tolerable daily intake (PMTDI) is 500 μg/day for body weight of 50 kg. The highest intake of perchlorate was 84 μg/day, where concentrations in foods were high, but not in water. The contribution of water to total perchlorate intake ranged from 0.5% to 22%, while the ratio of highest daily intake to RfD was 240% and that to PMTDI was 17%. Eight baby formulas were also tested--total chlorate and perchlorate intakes were 147 (42-332) μg/day and 1.11 (0.05-4.5) μg/day, respectively, for an ingestion volume of 1 L/day if prepared with tap water.

  7. Technological transformation of chlorate decomposing tank%氯酸盐分解槽的工艺改造

    Institute of Scientific and Technical Information of China (English)

    封小洪; 蒲云彬


    介绍氯酸盐产生的原因及危害,分析分解槽分解效率不高的原因,给出工艺改进方案和采取的改造措施.%The formation causes and harm of chlorate were introduced. The causes of low decomposition rate of chlorate in decomposer were analyzed. Process improvement plans and reform measures taken were provided.

  8. Development and trends in chlorine dioxide bleaching with integrated chlorate electrolysis for the cellulose industry

    Energy Technology Data Exchange (ETDEWEB)

    Wintzer, P.


    Rising demand for cellulose and paper and the environmental measures necessary in this branch of industry compel the companies involved to invest large sums. In particular, waste water from bleaching operations causes difficulties in biological waste water purification owing to high chlorolignin content. The sequence of chlorination steps have been optimized for each quality of wood, and the increasing use of chlorine dioxide leads to an expansion of chlorate electrolysis and chlorine dioxide plant at the expense of chlorine. The consumption of chemicals for the various cellulose qualities is considered. During the past 30 years, the Muenchner process for production of ClO/sub 2/ has proved environmentally sound and is being continuously improved. Only hydrochloric acid and water are needed as raw materials. The chlorine formed in this process is converted into hydrochloric acid, hypochlorite, and chlorine water. All steps of the processes require only liquids and gases permitting a favourable, closed mode of operation without by-products or waste salts. New chlorate cells built since 1969 are equipped exclusively with coated titanium anodes (load between 6 and 100 kA) with DC efficiencies of 92 to 95%. Annual world production of sodium chlorate exceeds 1 million tonnes. The rate of increase has long remained steady at 5%.

  9. Selectivity between Oxygen and Chlorine Evolution in the Chlor-Alkali and Chlorate Processes. (United States)

    Karlsson, Rasmus K B; Cornell, Ann


    Chlorine gas and sodium chlorate are two base chemicals produced through electrolysis of sodium chloride brine which find uses in many areas of industrial chemistry. Although the industrial production of these chemicals started over 100 years ago, there are still factors that limit the energy efficiencies of the processes. This review focuses on the unwanted production of oxygen gas, which decreases the charge yield by up to 5%. Understanding the factors that control the rate of oxygen production requires understanding of both chemical reactions occurring in the electrolyte, as well as surface reactions occurring on the anodes. The dominant anode material used in chlorate and chlor-alkali production is the dimensionally stable anode (DSA), Ti coated by a mixed oxide of RuO2 and TiO2. Although the selectivity for chlorine evolution on DSA is high, the fundamental reasons for this high selectivity are just now becoming elucidated. This review summarizes the research, since the early 1900s until today, concerning the selectivity between chlorine and oxygen evolution in chlorate and chlor-alkali production. It covers experimental as well as theoretical studies and highlights the relationships between process conditions, electrolyte composition, the material properties of the anode, and the selectivity for oxygen formation.

  10. Determination of chlorate and chlorite and mutagenicity of seafood treated with aqueous chlorine dioxide. (United States)

    Kim, J; Marshall, M R; Du, W X; Otwell, W S; Wei, C I


    The use of chlorine dioxide (ClO(2)) as a potential substitute for aqueous chlorine to improve the quality of seafood products has not been approved by regulatory agencies due to health concerns related to the production of chlorite (ClO(2)(-)) and chlorate (ClO(3)(-)) as well as possible mutagenic/carcinogenic reaction products. Cubes of Atlantic salmon (Salmo salar) and red grouper (Epinephelus morio) were treated with 20 or 200 ppm aqueous chlorine or ClO(2) solutions for 5 min, and extracts of the treated fish cubes and test solutions were checked for mutagenicity using the Ames Salmonella/microsome assay. No mutagenic activity was detected in the treated fish samples or test solutions with ClO(2). Only the sample treated with 200 ppm chlorine showed weak mutagenic activity toward S. typhimurium TA 100. No chlorite residue was detected in sea scallops, mahi-mahi, or shrimp treated with ClO(2) at 3.9-34.9 ppm. However, low levels of chlorate residues were detected in some of the treated samples. In most cases, the increase in chlorate in treated seafood was time- and dose-related.

  11. EFSA CONTAM Panel (EFSA Panel on Contaminants in the Food Chain), 2015. Scientific Opinion on risks for public health related to the presence of chlorate in food

    DEFF Research Database (Denmark)

    Petersen, Annette

    Following a request from the European Commission, the risks to human health related to the presence of chlorate in food were assessed by the EFSA Panel on Contaminants in the Food Chain (CONTAM Panel). The presence of chlorate in food can arise from the use of chlorinated water for food processin...


    Institute of Scientific and Technical Information of China (English)

    WANG Tao; DUAN Li


    Both a real time optical interferometric experiment and a numerical simulation of two-dimension non-steady state model were employed to study the growth process of aqueous sodium chlorate crystals. The parameters such as solution concentration distribution, crystal dimensions, growth rate and velocity field were obtained by both experiment and numerical simulation. The influence of earth gravity during crystal growth process was analyzed. A reasonable theory model corresponding to the present experiment is advanced. The thickness of concentration boundary layer was investigated especially. The results from the experiment and numerical simulation match well.

  13. (Per)chlorate reduction by an acetogenic bacterium, Sporomusa sp., isolated from an underground gas storage.

    KAUST Repository

    Balk, Melike


    A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 converted various alcohols, organic acids, fructose, acetoin, and H(2)/CO(2) to acetate, usually as the only product. Succinate was decarboxylated to propionate. The isolate was able to respire with (per)chlorate, nitrate, and CO(2). The G+C content of the DNA was 42.6 mol%. Based on the 16S rRNA gene sequence analysis, strain An4 was most closely related to Sporomusa ovata (98% similarity). The bacterium reduced perchlorate and chlorate completely to chloride. Key enzymes, perchlorate reductase and chlorite dismutase, were detected in cell-free extracts.

  14. Effect of intravenous or oral sodium chlorate administration on the fecal shedding of Escherichia coli in sheep (United States)

    The effect of gavage or intravenous (i.v.) administration of sodium chlorate salts on the fecal shedding of generic Escherichia coli in wether lambs was studied. To this end, 9 lambs (27 +/- 2.5 kg) were administered 150 mg NaClO3 per kg BW by gavage or i.v. infusion in a cross-over design with sal...

  15. Evaluation of sodium chlorate as a pre-harvest intervention for controlling Salmonella in the peripheral lymph nodes of cattle (United States)

    The objective of the current study was to evaluate sodium chlorate as a potential pre-harvest intervention for reducing or eliminating Salmonella from the peripheral lymph nodes of experimentally-infected cattle. The peripheral lymph nodes of Holstein steers (approx. BW = 160 kg; 4 and 6 head in co...

  16. Effects of chlorate on the sulfation process of Trypanosoma cruzi glycoconjugates. Implication of parasite sulfates in cellular invasion. (United States)

    Ferrero, Maximiliano R; Soprano, Luciana L; Acosta, Diana M; García, Gabriela A; Esteva, Mónica I; Couto, Alicia S; Duschak, Vilma G


    Sulfation, a post-translational modification which plays a key role in various biological processes, is inhibited by competition with chlorate. In Trypanosoma cruzi, the agent of Chagas' disease, sulfated structures have been described as part of glycolipids and we have reported sulfated high-mannose type oligosaccharides in the C-T domain of the cruzipain (Cz) glycoprotein. However, sulfation pathways have not been described yet in this parasite. Herein, we studied the effect of chlorate treatment on T. cruzi with the aim to gain some knowledge about sulfation metabolism and the role of sulfated molecules in this parasite. In chlorate-treated epimastigotes, immunoblotting with anti-sulfates enriched Cz IgGs (AS-enriched IgGs) showed Cz undersulfation. Accordingly, a Cz mobility shift toward higher isoelectric points was observed in 2D-PAGE probed with anti-Cz antibodies. Ultrastructural membrane abnormalities and a significant decrease of dark lipid reservosomes were shown by electron microscopy and a significant decrease in sulfatide levels was confirmed by TLC/UV-MALDI-TOF-MS analysis. Altogether, these results suggest T. cruzi sulfation occurs via PAPS. Sulfated epitopes in trypomastigote and amastigote forms were evidenced using AS-enriched IgGs by immunoblotting. Their presence on trypomastigotes surface was demonstrated by flow cytometry and IF with Cz/dCz specific antibodies. Interestingly, the percentage of infected cardiac HL-1 cells decreased 40% when using chlorate-treated trypomastigotes, suggesting sulfates are involved in the invasion process. The same effect was observed when cells were pre-incubated with dCz, dC-T or an anti-high mannose receptor (HMR) antibody, suggesting Cz sulfates and HMR are also involved in the infection process by T. cruzi.

  17. Ordinary Toxicity of Chlorine Dioxide and By-products Chlorite and Chlorate in Water

    Institute of Scientific and Technical Information of China (English)

    王丽; 常爱敏; 黄君礼


    Acute toxicity and accumulated toxicity of chlorine dioxide (C1O2) and by-products chlorite ( C1O-2 ) and chlorate (C1O-3) in water acted on mice are studied by the method of Horn and accumulation coefficient.Subchronic toxicity of the mixture of C1O2 and C1O-2 and ClO-3 in water acted on rat is studied though feeding test for 90 days, including statistical analysis of variance on weight gaining, food utilization efficiency, index of blood and serum, liver (or kidney)to body weight ratio, and histopathological examination on liver and kidney. The results show that aqueous solution of C1O2, NaC1O2 and NaC1O3 (with the concentration of 276. 5 mg/L, 200 mg/L and 200 mg/L respectively) and the mixed aqueous solution of C1O2 with the concentration of 553 mg/L are actually non poisonous, and non-cumulative aqueous solution as well.

  18. Synthesis and crystal structure of chlorate-enclathrated in aluminogermanate sodalite Na8[AlGeO4]6(ClO3)2 (United States)

    Borhade, Ashok V.; Dholi, Arun G.


    Encapsulation of chlorate in sodalite with aluminogermanate host framework has been obtained by one pot hydrothermal synthesis at 393 K. The crystal structure of Na8[AlGeO4]6(ClO3)2; sodalite was refined from X-ray powder data in the space group Pbar 43 n: a = 9.169 Å, where Al-O-Ge angle is 137.6°. The 27Al MAS NMR study confirmed alternate Ge and Al ordering of the sodalite framework, while 23Na gave insight into the structure and dynamics of the cage fillings. Infrared spectrum confirmed the encapsulation of chlorate as well as the framework formation of aluminogermanate sodalite. SEM study showed the retention of cubical morphology of the aluminogermanate sodalite. Thermogravimetric analysis provided information on the extent of chlorate entrapment, stability within the sodalite cages and decomposition properties.

  19. Microbial respiration with chlorine oxyanions: diversity and physiological and biochemical properties of chlorate- and perchlorate-reducing microorganisms. (United States)

    Liebensteiner, Martin G; Oosterkamp, Margreet J; Stams, Alfons J M


    Chlorine oxyanions are valuable electron acceptors for microorganisms. Recent findings have shed light on the natural formation of chlorine oxyanions in the environment. These suggest a permanent introduction of respective compounds on Earth, long before their anthropogenic manufacture. Microorganisms that are able to grow by the reduction of chlorate and perchlorate are affiliated with phylogenetically diverse lineages, spanning from the Proteobacteria to the Firmicutes and archaeal microorganisms. Microbial reduction of chlorine oxyanions can be found in diverse environments and different environmental conditions (temperature, salinities, pH). It commonly involves the enzymes perchlorate reductase (Pcr) or chlorate reductase (Clr) and chlorite dismutase (Cld). Horizontal gene transfer seems to play an important role for the acquisition of functional genes. Novel and efficient Clds were isolated from microorganisms incapable of growing on chlorine oxyanions. Archaea seem to use a periplasmic Nar-type reductase (pNar) for perchlorate reduction and lack a functional Cld. Chlorite is possibly eliminated by alternative (abiotic) reactions. This was already demonstrated for Archaeoglobus fulgidus, which uses reduced sulfur compounds to detoxify chlorite. A broad biochemical diversity of the trait, its environmental dispersal, and the occurrence of relevant enzymes in diverse lineages may indicate early adaptations of life toward chlorine oxyanions on Earth.

  20. Genome and proteome analysis of Pseudomonas chloritidismutans AW-1T that grows on n-decane with chlorate or oxygen as electron acceptor

    NARCIS (Netherlands)

    Mehboob, F.; Oosterkamp, M.J.; Koehorst, J.J.; Farrakh, S.; Veuskens, T.; Plugge, C.M.; Boeren, S.; Vos, de W.M.; Schraa, G.; Stams, A.J.M.; Schaap, P.J.


    Growth of Pseudomonas chloritidismutans AW-1T on C7 to C12 n-alkanes with oxygen or chlorate as electron acceptor was studied by genome and proteome analysis. Whole genome shotgun sequencing resulted in a 5 Mbp assembled sequence with a G+C content of 62.5% The automatic annotation identified 4767 p


    Directory of Open Access Journals (Sweden)

    Ludmila Kiriyak


    Full Text Available The polarographic catalytic current in acid solutions of Mo(VI, 2,3-dihydroxybenzaldehyde (2,3-DHBA and chlorate ions has been investigated. The scheme of reactions taking place in the solutions and on the electrode has been elaborated. The increase of the catalytic current is explained by the formation of the active intermediate complex [Mo(V×2,3-DHBA (ClO3-]. The rate constant of formation for the active intermediate complex K = 2.5 × 106 mol-1 × dm3 × s-1, the activation energy of reaction Ea=14.0 kcal×mol-1 and the activation entropy ∆Sa¹= -28.3 e.u. have also been determined.

  2. Structure effect of molybdenum (5) complexes on its activity in appearance of catalytic polarographic currents of chlorate- and perchlorate ions

    Energy Technology Data Exchange (ETDEWEB)

    Zajtsev, P.M.; Zhdanov, S.I.; Dergacheva, E.N.; Savchenko, E.N.; Nikolaeva, T.D. (Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Khimicheskikh Reaktivov i Osobo Chistykh Veshchestv, Moscow (USSR))


    Polarographic behaviour and reactivity of synthesized molybdenum (5) in reactions, conditioning catalytic currents of ClO/sub 3//sup -/ and ClO/sub 4//sup -/ have been studied. Their comparison with similar characteristics for molybdenum (5) appearing in the process of Mo (6) solution polarography is made. For the purpose a salt of molybdenum (5) in H/sub 2/SO/sub 4/, HCl and HClO/sub 4/ solutions have been synthesized by electrochemical and chemical ways. It has been established that in reactions conditioning catalytic currents of chlorate- and perchlorate-ions the preservation of structure of Mo (6) complex in the Mo (5) complex formed, i.e. processes of Mo (5) complex ageing, plays a very significant role.

  3. 氯酸盐电解槽废气的处理%Waste gas treatment of chlorate electrolyzers

    Institute of Scientific and Technical Information of China (English)



    Based on the analysis about the waste gas produced from chlorate electrolyzers, waste gas treatment technology of chlorate electrolyzers was introduced as follows;firstly,content of chlorine in waste gas is reduced by 50% after pre-treatment;then,volume fraction of chlorine is below 2 × 10-5 through the absorption columns in series, whose absorber is NaOH solution;finally,by the deoxygenization column with palladium as catalyst and Al2O3 as carrier,the gas is transported to the next procedure through water-ring vacuum pump and compressor. Some attentive problems and appropriate measures in the process of waste gas treatment were put forward.%对氯酸盐电解槽废气的产生进行分析.介绍了电解槽废气处理的工艺:经过预处理,使气体中氯气含量降低50%,再经过以氢氧化钠溶液为氯气吸收剂的串联吸收塔,可使氯气体积分数达2×10-5以下;将该气体通过以钯为催化剂、三氧化二铝为载体的除氧塔进行处理,经水环式真空泵及压缩机输送至下一工序予以利用.提出了废气处理过程中应注意的问题以及应采取的措施.

  4. 氯酸钾制备膨胀石墨的研究%Preparation of Expanded Graphite by Potassium Chlorate

    Institute of Scientific and Technical Information of China (English)

    彭颖昊; 蒋述兴


    Low-temperature expandable graphite with high initial expansion temperature was prepared using the potassium chlorate as the solid oxidant. Reaction conditions was researched on the low-temperature expandable graphite swelling volume, the results showed that the initial expansion temperature was 260℃, and the expansion was up to 300 mL/g at 400℃ while taking 5 g of graphite, 0.6 g of potassium chlorate, 13.5 ml of concentrated sulfuric and 4.5 mL of concentrated nitricacid reacting 60 min at 20 ℃. The X-ray diffraction confirmed the formation of graphite intercalation compounds, and the SEM showed the microstructure of expanded graphite.%以氯酸钾为固体氧化剂,制备了高起始膨胀温度的低温可膨胀石墨.考察了反应条件对可膨胀石墨低温膨胀体积的影响,确定了最佳工艺条件:5g石墨配以0.6g氯酸钾、13.5 mL浓硫酸、4.5 mL浓硝酸、在20℃时反应60min.此条件下得到的可膨胀石墨起始膨张温度为260℃,在400℃时膨胀体积为300 mL/g.X射线衍射证实了石墨层间化合物的生成,并利用SEM扫描电镜分析了膨胀石墨的微观结构.

  5. Disinfection by-products of chlorine dioxide (chlorite, chlorate, and trihalomethanes): Occurrence in drinking water in Qatar. (United States)

    Al-Otoum, Fatima; Al-Ghouti, Mohammad A; Ahmed, Talaat A; Abu-Dieyeh, Mohammed; Ali, Mohammed


    The occurrence of chlorine dioxide (ClO2) disinfection by-products (DBPs) in drinking water, namely, chlorite, chlorate, and trihalomethanes (THMs), was investigated. Two-hundred-ninety-four drinking water samples were collected from seven desalination plants (DPs), four reservoirs (R), and eight mosques (M) distributed within various locations in southern and northern Qatar. The ClO2 concentration levels ranged from 0.38 to <0.02 mg L(-1), with mean values of 0.17, 0.12, and 0.04 mg L(-1) for the DPs, Rs, and Ms, respectively. The chlorite levels varied from 13 μg L(-1) to 440 μg L(-1), with median values varying from 13 to 230 μg L(-1), 77-320 μg L(-1), and 85-440 μg L(-1) for the DPs, Rs, and Ms, respectively. The chlorate levels varied from 11 μg L(-1) to 280 μg L(-1), with mean values varying from 36 to 280 μg L(-1), 11-200 μg L(-1), and 11-150 μg L(-1) in the DPs, Rs, and Ms, respectively. The average concentration of THMs was 5 μg L(-1), and the maximum value reached 77 μg L(-1) However, all of the DBP concentrations fell within the range of the regulatory limits set by GSO 149/2009, the World Health Organization (WHO), and Kahramaa (KM).

  6. 氯酸盐电解槽爆炸原因分析%Analysis of the reason of chlorate electrolyzer explosion

    Institute of Scientific and Technical Information of China (English)



    The phenomenon and the reason of chlorate electrolyzer explosion in operation was analyzed. At the same time, the corresponding measures were put forward.%详细分析了氯酸盐电解槽在操作时发生爆炸的现象和原因,同时,也提出了应采取的相应措施。

  7. Enantioselective Crystallization of Sodium Chlorate in the Presence of Racemic Hydrophobic Amino Acids and Static Magnetic Fields

    Directory of Open Access Journals (Sweden)

    María-Paz Zorzano


    Full Text Available We study the bias induced by a weak (200 mT external magnetic field on the preferred handedness of sodium chlorate crystals obtained by slow evaporation at ambient conditions of its saturated saline solution with 20 ppm of added racemic (dl hydrophobic amino acids. By applying the Fisher test to pairs of experiments with opposing magnetic field orientation we conclude, with a confidence level of 99.7%, that at the water-air interface of this saline solution there is an enantioselective magnetic interaction that acts upon racemic mixtures of hydrophobic chiral amino acids. This interaction has been observed with the three tested racemic hydrophobic amino acids: dl-Phe, dl-Try and dl-Trp, at ambient conditions and in spite of the ubiquitous chiral organic contamination. This enantioselective magnetic dependence is not observed when there is only one handedness of added chiral amino-acid, if the added amino acid is not chiral or if there is no additive. This effect has been confirmed with a double blind test. This novel experimental observation may have implications for our view of plausible initial prebiotic scenarios and of the roles of the geomagnetic field in homochirality in the biosphere.

  8. 氯酸钠生产中母液处理工艺研究%Study on treatment process of mother liquor in sodium chlorate industry

    Institute of Scientific and Technical Information of China (English)

    郭淑芬; 周俊波; 潘胜


    Recently .chemical precipitation is used for treating sulfate radicals in the sodium chlorate production, but produces a considerable amount of sludge containing Cr,causing pollution to the environment.The use of ion exchange resin and nanofiltration membrane device integrated treatment of sodium chlorate industry crystallization mother liquor was presented.This method not only could recover sodium dichromate but also could remove sulfate radicals.Results showed that the recovery rate of sodium dichromate could reach 98%, and the content of sodium sulfate in the crystallization mother liquor was less than 3 g/L after treatment, reaching the recycling requirements.%目前,在氯酸钠生产中常用化学沉淀法处理硫酸根,但是会产生大量含铬污泥,污染环境.提出利用离子交换树脂和纳滤膜装置综合处理结晶母液的方法,既能回收重铬酸钠又能脱除硫酸根.实验结果表明,重铬酸钠的回收率可达98%,结晶母液处理后硫酸钠质量浓度低于3 g/L,达到母液循环利用的要求.


    Institute of Scientific and Technical Information of China (English)

    张广惠; 张玉生


    The treatment technology for the three wastes( water, gas and sludge)in the production of sodium chlorate is introduced. By practice, it proves that this technology is reasonable, the utilization ratio of resources is high and the pollution is decreased.%介绍万吨工业氯酸钠生产中废水、废气、废渣的处理技术,实践证明,三废治理的工艺是合理的,原料有效成分利用率高,节约了资源,减少了二次污染,各项指标均达到排放标准。


    Directory of Open Access Journals (Sweden)

    Ludmila Chiriac


    Full Text Available The polarographic catalytic current in acid solutions of Mo(VI, thiosemicarbazone 2,3-dihydroxybenzaldehyde (TSC 2,3-DHBA and chlorate ions has been investigated. The scheme of reactions, taking place in the solutions and on the electrode, has been proposed. The increase of the catalytic current is explained by the formation of an active intermediate complex [Mo(V×TSC 2,3-DHBA (ClO-3]. The rate constant of this complex formation K = 2.56 × 106 mol-1×dm3×s-1, the activation energy Ea = 15.9 kcal×mol-1 and the reaction activation entropy ∆Sa¹ = -23.5 e.u. have been calculated.

  11. Control of Sulfidogenesis Through Bio-oxidation of H2S Coupled to (per)chlorate Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, Patrick [Univ. of California, Berkeley, CA (United States); Engelbrektson, Anna [Univ. of California, Berkeley, CA (United States); Hubbard, Christopher G. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Metlagel, Zoltan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Csencsits, Roseann [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Auer, Manfred [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thieme, Jurgen [Brookhaven National Lab. (BNL), Upton, NY (United States); Northrup, Paul [Brookhaven National Lab. (BNL), Upton, NY (United States); Coates, John D. [Univ. of California, Berkeley, CA (United States)


    Here, we investigate H2S attenuation by dissimilatory perchlorate-reducing bacteria (DPRB). All DPRB tested oxidized H2S coupled to (per)chlorate reduction without sustaining growth. H2S was preferentially utilized over organic electron donors resulting in an enriched (34S)-elemental sulfur product. Electron microscopy revealed elemental sulfur production in the cytoplasm and on the cell surface of the DPRB Azospira suillum. We also propose a novel hybrid enzymatic-abiotic mechanism for H2S oxidation similar to that recently proposed for nitrate-dependent Fe(II) oxidation. The results of this study have implications for the control of biosouring and biocorrosion in a range of industrial environments.

  12. The Two-stage Push Material Centrifuge In The Production Of Sodium Chlorate Application And Improvement%双级推料离心机在氯酸钠生产中的应用及改进

    Institute of Scientific and Technical Information of China (English)

    余浩; 崔政


    双级活塞推料离心机以其独有的自动连续操作、生产能力高、功率消耗低等优势,已被越来越多的氯酸盐生产企业认识和使用。针对双级推料离心机结构特点、氯酸钠物料特性及在氯酸钠脱水中存在的问题,提出了对双级推料离心机在结构及操作维护上的改进。%Two-stage push centrifuges with its unique automatic and continuous operation,high productive capacity,low power consumption advantages,has been more and more the chlorate production companies know and use.In view of the two-stage push material structure characteristics,sodium chlorate centrifuge material properties and the problem in sodium chlorate dehydration,it presents Two-stage pusher centrifuges in structure and operation and maintenance centrifuge on improvement.

  13. Effect of the presence of chlorates and perchlorates on the pyrolysis of organic compounds: implications for measurements done with the SAM experiment onboard the Curiosity rover (United States)

    Millan, Maeva; Szopa, Cyril; Buch, Arnaud; Belmahdi, Imène; Coll, Patrice; Glavin, Daniel P.; Freissinet, Caroline; Archer, Doug; Sutter, Brad; Summons, Roger E.; Navarro-Gonzalez, Rafael; Cabane, Michel; Mahaffy, Paul


    The Sample Analysis at Mars (SAM) experiment onboard the Curiosity rover of the Mars Science Laboratory mission is partly devoted to the in situ molecular analysis of gases evolving from solid samples collected on Mars surface/sub-surface. SAM has a gas-chromatograph coupled to a quadrupole mass spectrometer (GC-QMS) devoted to the separation and identification of organic and inorganic material [1]. Before proceeding to the GC-QMS analysis, the solid sample collected by Curiosity is subjected to a thermal treatment thanks to the pyrolysis oven to release the volatiles into the gas processing system. As the Viking landers in 1976 [2], SAM detected chlorohydrocarbons with the pyrolysis GC-QMS experiment [3,4]. The detection of perchlorates salts in soil at the Phoenix Landing site [6] suggests that these chlorohydrocarbons could come from the reaction of organics with oxychlorines. Oxychlorines indeed decomposed into molecular oxygen and volatile chlorine when heated and react with the organic matter in the samples by oxidation and/or chlorination processes. [3,5,7,8]. During SAM pyrolysis, samples are heated to 850°C. SAM detected C1 to C3 chloroalkanes, entirely attributed to reaction products occurring during the pyrolysis experiment between oxychlorines and organic carbon from instrument background [3] and chlorobenzene and C2 to C4 dichloroalkanes produced by reaction between Mars endogenous organics with oxychlorines [4]. To help understanding the influence of perchlorate and chlorate salts on organic matter during SAM pyrolysis, we systemically study the reaction products formed during pyrolysis of various organic compounds mixed with various perchlorates and chlorates. We selected organics from simple molecule forms as for instance PAHs and amino acids to complex material (>30 carbon atoms) such as kerogen. The perchlorate and chlorate salts are prepared at 1 wt % concentration in silica and mixed with the organics to study the potential qualitative and

  14. 离子膜电解盐水中氯酸盐含量的测定%Determination of chlorate content in brine for ion-exchange membrane electrolyzsis

    Institute of Scientific and Technical Information of China (English)



    提出用双氧水测定离子膜法烧碱生产用的盐水中的氯酸盐含量。试验结果表明:采用该法检测,相对标准偏差低于0.4%,回收率在99%以上。%A method of using hydrogen peroxide to determine chlorate content in brine used for production of ion-exchange membrane caustic soda was proposed.Test results showed that relative standard deviation was lower than 0 .4%, and recovery rate was more than 99%.

  15. Development of Detection Method for Chlorates of Alkali Metals in Cosmetics%化妆品中碱金属氯酸盐的检测方法研究

    Institute of Scientific and Technical Information of China (English)

    杨轶眉; 李勤; 薛峰


    A thin layer chromatography(TCL)&potentiometric titration method was developed for the determination of chlo-rates of alkali metals in cosmetics. Chlorates were separated from other halates by thin layer chromatography and identified by the oxidation of iodide to form iodine. After identification,chlorate was reduced by zinc powder under acid conditions. The formed chloride was measured by potentiometric titration using a silver nitrate solution. The results showed that the recovery of the method was in the range of 81.4% to 105.2% under the concentration of 0.03% to 3.41% while being counted as chlorate ions(with relative standard deviation of not more than 10% ). Additionally,the detection and quantification limits were found to be 0.03% and 0.10% respectively.%建立了薄层色谱法和电位滴定法联用测定化妆品中碱金属氯酸盐含量的方法。用薄层色谱将氯酸盐从其他卤酸盐中分离,与碘化物形成碘来鉴别碱金属的氯酸盐。通过鉴别试验后,在酸性条件下氯酸盐被锌粉还原,所形成的氯化物用硝酸银溶液进行电位滴定。试验结果表明:在0.03%~3.41%(以氯酸根离子计)的质量分数范围内,加标回收率为81.4%~105.2%,相对标准偏差(RSD)≤10%;定性检出限为0.03%(质量分数),定量检出限为0.10%(质量分数)。

  16. Ion chromatographic determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water using suppressed conductivity detection and visible detection. (United States)

    Binghui, Zhu; Zhixiong, Zhong; Jing, Yao


    An ion chromatography method for the simultaneous determination of trace iodate, chlorite, chlorate, bromide, bromate and nitrite in drinking water has been developed using an anion-exchange column and the suppressed conductivity detector, followed by post-column addition of reagent to enhance visible absorbance detection of ions. A high capacity anion exchange Ion Pac9-HC column (250 mm x 4 mm I.D.) was used. Eight millimole per liter sodium carbonate was used as eluent, an auto-suppression external water mode was selected, 0.5 g/l o-dianisidine.2HCl (ODA)+4.5 g/l KBr+25% methanel+5.6% nitric acid was used as post-column reagent. The post-column reaction (PCR) temperature was at 60 degrees C, and the visible absorbance detected wavelength at 450 nm. The sample's pH and coexist anions had no influence on determination. The method enjoyed a wide linear range and a good linear correlation coefficient (r>0.999). The method detection limits were between 0.023 and 2.0 microg/l. The average recoveries ranged from 87.5 to 110.0%, and the relative standard deviations (RSD) were in the range of 1.1-4.6%. The analytical results by the method of post-column addition of reagent to enhance visible absorbance detection of anions was compared with that of the suppressed conductivity detection, and the former was proved to be better in sensitivity and selectivity. The results showed that this method was accurate, sensitive and might be good for application and suitable for trace analysis at the level of mug/l.

  17. Thermal Reactivity of Organic Molecules in the Presence of Chlorates and Perchlorates and the Quest for Organics on Mars with the SAM Experiment Onboard the Curiostiy Rover (United States)

    Szopa, Cyril; Millan, Maeva; Buch, Arnaud; Belmahdi, Imene; Coll, Patrice; Glavin, Daniel P.; Freissinet, Caroline; Eigenbrode, Jennifer; archer, doug; sutter, brad; Summons, Roger; Navarro-Gonzalez, Rafael; Mahaffy, Paul; cabane, Michel


    One of the main objectives of the Sample Analysis at Mars (SAM) experiment is the in situ molecular analysis of gases evolving from solid samples collected by Curiosity when they are heated up to ~850°C. With this aim SAM uses a gas-chromatograph coupled to a mass spectrometer (GC-MS) able to detect and identify both inorganic and organic molecules released by the samples.During the pyrolysis, chemical reactions occur between oxychlorines, probably homogeneously distributed at Mars's surface, and organic compounds SAM seeks for. This was confirmed by the first chlorohydrocarbons (chloromethane and di- and trichloromethane) detected by SAM that were entirely attributed to reaction products occurring between these oxychlorines and organics from instrument background. But SAM also detected in the Sheepbed mudstone of Gale crater, chloroalkanes produced by reaction between oxychlorines and Mars indigenous organics, proving for the first time the presence of organics in the soil of Mars. However, the identification of the molecules at the origin of these chloroalkanes is much more difficult due to the complexity of the reactivity occurring during the sample pyrolysis. If a first study has already been done recently with this aim, it was relatively limited in terms of parameters investigated.This is the reason why, we performed a systematic study in the laboratory to help understanding the influence of oxychlorines on organic matter during pyrolysis. With this aim, different organic compounds from various chemical families (e.g. amino and carboxylic acids) mixed with different perchlorates and chlorates, in concentrations compatible with the Mars soil from estimations done with SAM measurements, were pyrolyzed under SAM like conditions. The products of reaction were analyzed and identified by GC-MS in order to show a possible correlation between them and the parent molecule. Different parameters were tested for the pyrolysis to evaluate their potential influence on the

  18. 氢氧化钠溶液中氯酸钠含量测定方法探究%Study on the content determination method of sodium chlorate in sodium hydroxide solution

    Institute of Scientific and Technical Information of China (English)

    李云枫; 王世荣


    对GB/T11200.1—89与GB/T11200.1—2006测定氢氧化钠溶液中氯酸钠含量的方法进行了分析,对GB/T11200.1—89测定氢氧化钠溶液中氯酸钠含量分析方法进行了实验研究,并提出了修改建议。%The content determination method of sodium chlorate in sodium hyd~vxide solution accrding to GB/T11200-89 and GB/T11200-2006 was studied by the experiment and analysis method. MoreoveL, some useful revisions were attempted, which make the content determin

  19. 饮用水中的亚氯酸盐、氯酸盐和溴酸盐的离子色谱测定法%Determination of Chlorite ,Chlorate and Bromate in Drinking Water by Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    周虹; 周小新


    Objective To develop an ion chromatography (IC) for simultaneous determination of chlorite, chlorate and bromate in drinking water. Methods The IC separation was carried out with the IonPAC AS23 column by using 4.5 mmol/L Na_2CO_3-0.8 mmol/L NaHCO_3 at the flow rate of 1.0 ml/min. The injection volume was 250 μl.the temperature of conductivity detector cell and column were 30 ℃ and 35 ℃, respectively. The pressure upon the bottle of mobile phase was 40 kPa. The current of auto-regenerating suppressor was 25 mA. Results The results showed that in the range of 0 to 1 000 mg/L, the calibration equation for chlorite was y=0.009 6+1.600 0 x (r=0.999 3),for bromate was y=0.003 2+3.184 7 x (r=0.999 9),for chlorate was y= 0.001 8+1.788 9 x(r=0.999 9).The detection limit of chlorite,chlorate and bromate were all 5 μg/ L,the recovery rates were 89.0% -108.0% and the relative standard deviations (RSD) were 0.21%-2.70%. Conclusion The method is simple,fast,accurate, sensitive, little interference and is applicable to the simultaneous determination of chlorite, chlorate and bromate in drinking water.%目的 建立同时测定饮用水中亚氯酸盐、氯酸盐和溴酸盐的离子色谱法.方法 选择IonPacAS23色谱柱,淋洗液为4.5mmol/L Na_2CO_3-0.8 mmol/L NaHCO_3,流速为1.0 ml/min,进样量为250 μl,电导检测池温度为30℃,色谱柱温度为35 ℃,流动相瓶加压为40 kPa,抑制器抑制模式为自动再生模式,抑制器电流为25 mA.结果 在0~1 000.0 mg/L范围内,亚氯酸盐的线性方程为:y=0.009 6+1.600 0x,r=0.999 3,检出限为5μg/L;溴酸盐的线性方程为:y=0.003 2+3.184 7x,r=0.999 9,检出限为5μg/L;氯酸盐的线性方程为:y=0.001 8+1.788 9x,r=0.999 9,检出限为5μg/L.加标回收试验结果显示,该方法的平均回收率为89.0%~108.0%,RSD为0.21%~2.70%.结论 该法操作简单、快速、准确,灵敏度高、干扰少,适用于饮用水中亚氯酸盐、氯酸盐和溴酸盐的同时测定.

  20. 生活饮用水中溴酸盐、氯酸盐和亚氯酸盐的离子色谱测定法%Determination of bromate, chlorate, and chlorite in drinking water by ion chromatography

    Institute of Scientific and Technical Information of China (English)

    孙卫明; 孙建飞; 王权帅


    [ Objective ] To establish a method for determination of bromate, chlorate, and chlorite in drinking water by ion chroma-tography. [ Methods] ] After filtration by 0.22 μm membrane filter, The water samples were put into the ion exchange system of ion chromatography, with the potassium hydroxide eluent. Different ions separated with the different affinity in one separation column and determined quantitatively by the external standard method. [ Results] Recoveries of bromate were 87.5% to 116.0% , and the relative standard deviation (RSD) was 69% ; recoveries of chlorate were 86. 8% to 99.0% , with RSD of 1. 21% ; recoveries of chlorite of 80.1% to 87.0% , with the RSD of 0.93% and the correlation coefficients of all 3 ions were r >0.999 0. [ Conclusion] This method is simple, rapid, can obtain satisfactory separation, with high sensitivity and precision. Also, the recovery meets the methodological requirements. Above all, this method is entirely suitable for the simultaneous determination of bromate, chlorate, and chlorite in drinking water.%目的 建立离子色谱法测定生活饮用水中有溴酸盐、氯酸盐、亚氯酸盐的检测方法.方法 水样经0.22 μm滤膜过滤后,随氢氧化钾淋洗液进入离子色谱的离子交换系统.根据分离柱对不同离子的亲和力不同进行分离,外标法定量.结果 溴酸盐回收率为87.5% ~ 116.0%,相对标准偏差为2.69%;氯酸盐回收率为86.8%~ 99.0%,相对标准偏差为1.21%;亚氯酸盐回收率为80.1% ~ 87.0%,相对标准偏差为0.93%.以上3个项目相关系数均大于0.999 0.结论 该方法检测速度快,样品处理简便,能获得满意的分离效果,具有较高的灵敏度和精密度,回收率也满足方法学要求,完全适合于生活饮用水中有溴酸盐、氯酸盐、亚氯酸盐的同时测定.

  1. Determination of Chlorite, Bromate, Chlorate in Surface Water and Drinking Water by Ion Chromatography%离子色谱法测定地表水和饮用水中亚氯酸盐、溴酸盐和氯酸盐

    Institute of Scientific and Technical Information of China (English)

    窦艳艳; 杨丽莉; 徐荣; 胡恩宇


    采用KOH梯度淋洗离子色谱法测定地表水和饮用水中ClO2-、BrO3-和ClO3-,在试验确定的条件下,3种离子与F-、Cl-、NO2-、NO3-、SO2-4、Br-、I-等7种离子分离度良好。 ClO2-、BrO3-、ClO3-在50.0μg/L~1000μg/L范围内线性良好,检出限分别为5.2μg/L、8.9μg/L、7.6μg/L,环境水样加标平行测定的RSD分别为2.1%~5.4%、4.1%~5.4%、2.5%~4.8%,两个质量浓度水平加标的平均回收率分别为93.7%~96.5%、90.3%~94.8%、98.7%~111%。%An ion chromatography method for determining chlorite , bromate and chlorate in surface water and drinking water was studied .The separation of the anions was achieved on an IonPac AS 19 Column with KOH as eluent, the chlorite, bromate, chlorate and other 7 kinds of anions could be well separated and determined within 25 min by employing a concentration gradient .The method has good linearity during the concentration 50.0 μg/L ~1 000 μg/L.The method detection limits of chlorite, bromate and chlorate was 5.2 μg/L, 8.9 μg/L and 7.6 μg/L, respectively.The RSD of the samples were 2.1%~5.4% ( chlorite), 4.1%~5.4%(bromate), and 2.5%~4.8% (chlorate).The recoveries of chlorite, bromate and chlorate in water samples were 93.7%~96.5%, 90.3%~94.8%and 98.7%~111%.

  2. 氯酸钠法制备二氧化氯还原剂研究进展%Research progress in reducing agent for preparation of chlorine dioxide by sodium chlorate process

    Institute of Scientific and Technical Information of China (English)

    李建生; 刘炳光; 孙宝丰; 董广前; 王芳


    对比介绍了氯酸钠法生产二氧化氯常用还原剂的特点;综述了氯酸钠法制备二氧化氯新还原剂(硫化合物、多元醇、有机酸、碳水化合物、尿素和乙二醛)的研究进展;讨论了氯酸钠法制备二氧化氯有机还原剂甲醇和乙二醛的作用机理;指出采用复合还原剂降低生产成本和采用有机还原剂同时制备两种有用产品是氯酸钠法制备二氧化氯还原剂发展趋势.%Characteristics of reducing agents commonly used in industrially producing chlorine dioxide were introduced with comparison.Research progress in new reducing agents,such as sulfur compound, poly alcohol, organic acid, carbohydrate, urea, and glyoxal for the preparation of chlorine dioxide by sodium chlorate process was summarized.Reaction mechanism of organic reducing agents, methanol and glyoxal, in preparation of chlorine dioxide was was pointed that decreasing production cost by using combined reducing agent as well as preparing two useful products simultaneously by using organic reducing agenl is the tendency of reducing agent development.

  3. Synthesis of CuO porous nanorods and their catalytic activity in the decomposition of potassium chlorate and peroxide%孔状氧化铜纳米棒的制备及其催化性能研究

    Institute of Scientific and Technical Information of China (English)

    徐惠; 黄剑; 陈泳


    Copper monoxide (CUO) porous nanorods of 100-200nm in diameter and 2-3μm in length were successfully synthesized using a hydrothermal reaction method in the presence of urea. The products were characterized by SEM., TEM, FT-IR, XRD and TG analysis techniques. The results of catalytic activity indicate that CuO nanocrystal promoted potassium chlorate and peroxide decomposition. When the ratio of H2O2 to CuP is 5 to 1,the decomposition of peroxide is perfect.%以硝酸铜为铜源,采用尿素矿化剂,通过水热法制得纳米氧化铜前驱体,高温煅烧后得到长21μm,直径200nm的氧化铜多孔纳米捧,所得产品尺寸均一,微孔分布均匀,排列整齐.通过IR、XRD、SEM以及TEM对其结构和形貌进行了表征.研究表明,所制备的纳米氧化铜多孔棒无需任何制样处理对氯酸钾和过氧化氢具有较高的催化活性,当n(H2O2):n(CuO)=5:1时,过氧化氢的分解速率最快.

  4. Spectrophotometric Determination of Nitrite by Catalytic Oxidation of Methyl Red with Potassium Chlorate%氯酸钾氧化甲基红催化光度法测定痕量亚硝酸根

    Institute of Scientific and Technical Information of China (English)

    李红艳; 李子荣


    This paper erects a new method for the storage of nitrite under normal temperature and pressure in brown volumetric flask storage by adding appropriate amount of sodium carbonate solution and sodium hydroxide.A method of measuring nitrite un-der the normal temperature and pressure is established.In the presence of nitrite, methyl red can be oxidized by potassium chlorate in the solution of H3 PO4 .Under the wavelength of maximum absorption 519nm and the conditions of the experiment, linear equa-tions: y =0.1443x +0.011, R =0.9990,linear range: 0.04 ~4.0 μg・ mL -1 , detection limit is 0.01μg・ mL -1 .The method is simple, fast, reproducible, energy saving and environmental protection,The method has been applied to the determination of boiling water, lake water and river water with satisfactory results.%  通过加入适量碳酸钠和氢氧化钠,用棕色容量瓶储藏,获得常温、常压下储存亚硝酸根的新方法。基于磷酸介质中,利用亚硝酸根对氯酸钾氧化甲基红褪色有诱导催化作用,建立了常温、常压下测定痕量亚硝酸根的方法,在最大吸收波长519 nm 及选择的试验条件下,线性方程 y =0.1463x +0.011,R =0.9990,线性范围0.04~4.0μg・ mL -1,检出限为0.01μg・ mL -1,该方法简单、快捷、重现性好,节能环保。

  5. Ion chromatography for simultaneous determination of bromate,chlorite and chlorate in drinking water%用离子色谱法同时测定生活饮水中溴酸盐、亚氯酸盐、氯酸盐

    Institute of Scientific and Technical Information of China (English)

    齐春华; 张颖; 王化勇


    Objective; To develop an ion chromatography (IC ) for simultaneous determination of chlorite, chlorate and bromate in drinking water. Methods: The IC separation was carried out with the IonPAC AS19 column by using hydroxide eluent at the flow rate of 1.0 ml/min. The injection volume was 500 jxl. Conductivity detection cell temperature was set at 30℃ , column temperature was set at 35℃. Suppressor was in automatic regeneration mode, suppressor current was 87 mA. Results: The results showed that in the range of 0 μg/L to 500 μg/L, the linear e-quation of chlorite was y =2. 640x -0.027, r =0.9999, the detection limit was 0. 1 μg/L; In the range of 0 μg/L ~ 100 μg/L, the linear equation of bromate was y = 1. 342x - 0. 003 , r - 0. 9999 , detection limit was 0. 5 μg/L; In the range of 0 μg/L -500 μg/L, the linear equation of chlorate was y =2. 157x -0. 043 , r -0. 9999, the detection limit was 0.2 μg/L. The recovery rates were 99. 70% ~102.6% and the relative standard deviations (RSD) were 1. 16% ~3.56%. Conclusion; The method is simple,fast,accurate, sensitive, little interference and applicable to the simultaneous determination of chlorite, chlorate and bromate in drinking water.%目的:建立能够同时测定生活饮用水中亚氯酸盐、氯酸盐和溴酸盐的离子色谱法.方法:选择Ion-PacAS19色谱柱,淋洗液为氢氧根淋洗液,流速为1.0 ml/min,进样量为500μl,电导检测池温度为30℃,色谱柱温度为35℃,抑制器抑制模式为自动再生模式,抑制器电流为87 mA.结果:在0μg/L ~ 500.0 μg/L范围内,亚氯酸盐的线性方程为:y=2.640x-0.027,r=0.9999,检出限为0.1 μg/L;在0μg/L ~ 100.0 μg/L溴酸盐的线性方程为:y=1.342x-0.003,r=0.9999,检出限为0.5 μg/L;在0μg/L~500.0 μg/L氯酸盐的线性方程为:y=2.157x-0.043,r=0.9999,检出限为0.2μg/L.加标回收试验结果显示,该方法的平均回收率为99.7% ~102.6%,RSD为1.16% ~3.56%.结论:该法操作简单、快速、准

  6. Simultaneous Determination of Trace Amount of Chlorite,Chlorate and Common Inorganic Anions in Running Water with kOH Isocratic Elution by Ion Chromatographic Method%KOH等度淋洗IC法同时测定自来水中微量ClO2-、ClO3-及常规阴离子

    Institute of Scientific and Technical Information of China (English)

    陈东; 罗倚坪


    The method to determine a trace of chlorite, chlorate and common inorganic anions in running water with KOH isocratic elution by ion chromatography was investigated. The conditions of method was that the concentration of KOH is 20. 5 mmol/L, the flow rate is 1. 0 mL/min, and the injection volume is 50 μL. The results showed that the concentration of F-,Cl-,NO3 -, SO4 2-,ClO2 -,ClO3 - in water was determined completely only in 12 minutes. The correlation coefficients of calibration curve was 0. 997 0-0. 999 9,while the detection limits was between 0. 05-7. 00 μg/L. The relative standard deviation( RSD) and the recoveries were between 0. 61%-3. 82%and 97. 6%-101. 7%, respectively. The method was sensitive, accurate and rapid, which was favorable to simultaneous quantification of chlorite, chlorate and common inorganic anions in drinking water.%建立了KOH等度淋洗离子色谱法同时测定自来水中微量亚氯酸盐、氯酸盐及氟化物、氯化物、硝酸盐、硫酸盐的分析方法。该方法以20.5 mmol/L KOH为淋洗液,流速1.0 mL/min,进样量50μL。结果表明,6种阴离子可在12分钟内检测完毕,各离子的线性相关系数为0.9970~0.9999;检出限为0.05~7.00μg/L;精密度为0.61%~3.82%;回收率为97.6%~101.7%,能够满足饮用水中这些指标的定量需要,是一种灵敏、准确、快速的理想方法。

  7. Environmental biotechnology and microbiology of (per)chlorate reducing bacteria

    NARCIS (Netherlands)

    Mehboob, F.; Schraa, G.; Stams, A.J.M.


    Perchlorates are the salts derived from perchloric acid (HClO4). They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders and are used extensively within the pyrotechnics industry, and ammonium perchlorate is also

  8. Anaerobic microbial degradation of organic pollutants with chlorate as electron acceptor

    NARCIS (Netherlands)

    Mehboob, F.


    Aliphatic and aromatic hydrocarbons are two groups of compounds that are widespread pollutants. The aerobic microbial degradation of aliphatic and aromatic hydrocarbons proceeds in general fast and has been widely studied, while the biodegradation in anoxic environments is often incomplete, proceeds

  9. Optimization of chlorate decomposition system%氯酸盐分解系统的优化

    Institute of Scientific and Technical Information of China (English)




  10. Safety and efficacy of low-dose, subacute exposure of mature ewes to sodium chlorate (United States)

    The objective was to determine the safety and efficacy of low-dose, subacute exposure of mature ewes to NaClO3 in the drinking water. Twenty-five ewes (BW = 62.5 ± 7.3 kg) were placed indoors in individual pens with ad libitum access to water and feed. After 7 d of adaptation, ewes were assigned ran...

  11. Microbial degradation of aliphatic and aromatic hydrocarbons with (per)chlorate as electron acceptor

    NARCIS (Netherlands)

    Mehboob, F.; Weelink, S.A.B.; Talarico Saia, F.; Junca, H.; Stams, A.J.M.; Schraa, G.


    "Water is life!" All active cellular systems require water as the medium and solvent of their metabolic activities. Hydrophobic compounds and structures, which tend to exclude water, though providing inter alia excellent sources of energy and a means of biological compartmentalization, present probl

  12. Sodium chlorate reduces presence of Escherichia coli in feces of lambs and ewes managed in shed-lambing systems (United States)

    Our objective was to establish doses of orally-administered NaClO3 that reduced presence of generic Escherichia coli in intestines of ewes and neonatal lambs managed in a shed-lambing system. Neonatal lambs (n = 32; age = 7.1 ± 1.2 d; BW = 6.8 ± 1.0 kg) and yearling ewes (n = 44; BW = 74.8 ± 5.6 kg)...

  13. Discussion on the material of chlorate decomposition tank%氯酸盐分解槽材质的探讨

    Institute of Scientific and Technical Information of China (English)



    为寻求合适的氯酸盐分解槽材质,选取了金属钛、海特隆197玻璃钢、DERAKANE470玻璃钢3种材质进行腐蚀试验对比,结果认为:金属钛耐高温氯酸盐腐蚀,但价格昂贵;海特隆197玻璃钢性能不理想; DERAKANE470玻璃钢耐高温氯酸盐性能较理想,使用寿命、价格适中.

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

    NARCIS (Netherlands)

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


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

  15. Microbial redox processes in deep subsurface environments and the potential application of (per)chlorate in oil reservoirs

    NARCIS (Netherlands)

    Liebensteiner, M.; Tsesmetzis, N.; Stams, A.J.M.; Lomans, B.P.


    The ability of microorganisms to thrive under oxygen-free conditions in subsurface environments relies on the enzymatic reduction of oxidized elements, such as sulfate, ferric iron, or CO2, coupled to the oxidation of inorganic or organic compounds. A broad phylogenetic and functional diversity of m

  16. 自冷结晶法在氯酸盐生产中的应用%Application of self-cooled crystallization process in production of chlorates

    Institute of Scientific and Technical Information of China (English)




  17. An analysis of relations for simultaneous production of after product of chlorate%浅析氯酸盐深加工产品的关联性

    Institute of Scientific and Technical Information of China (English)




  18. Improvement on Chloration Synthesis Process of 2,4-Dichlorotoluene%2,4-二氯甲苯氯化合成工艺的改进

    Institute of Scientific and Technical Information of China (English)



    针对目前国内2,4-二氯甲苯生产合成工艺中存在的问题,改进了合成工艺,最佳工艺条件为反应温度40 ℃,转速30 r/min以及多管道通氯,使氯化收率提高至75%,氯气利用率提高至90%.

  19. Discussion on decomposition conditions of chlorate in brine by experiment%盐水中氯酸盐分解条件试验探讨

    Institute of Scientific and Technical Information of China (English)

    吴军祥; 王秀萍


    介绍了氯碱生产中电解盐水中氯酸盐的分解试验,并根据试验结果确定氯酸盐分解的最佳条件是:氢离子浓度0.8 - 1.0 mol/L、分解温度90 ~95℃、分解时间15 ~20min.

  20. Effect of the Presence of Chlorates and Perchlorates on the Pyrolysis of Organic Compounds: Implications for Measurements Done with the SAM Experiment Onboard the Curiosity Rover (United States)

    Millan, M.; Szopa, C.; Buch, A.; Belmahdi, I.; Coll, P.; Glavin, D. P.; Freissinet, C.; Archer, P. D., Jr.; Sutter, B.; Summons, R. E.; Mahaffy, P.


    The Mars Science Laboratory (MSL) Curiosity Rover carries a suite of instruments, one of which is the Sample Analysis at Mars (SAM) experiment. SAM is devoted to the in situ molecular analysis of gases evolving from solid samples collected by Curiosity on Mars surface/sub-surface. Among its three analytical devices, SAM has a gaschromatograph coupled to a quadrupole mass spectrometer (GC-QMS). The GC-QMS is devoted to the separation and identification of organic and inorganic material. Before proceeding to the GC-QMS analysis, the solid sample collected by Curiosity is subjected to a thermal treatment thanks to the pyrolysis oven to release the volatiles into the gas processing system. Depending on the sample, a derivatization method by wet chemistry: MTBSTFA of TMAH can also be applied to analyze the most refractory compounds. The GC is able to separate the organic molecules which are then detected and identified by the QMS (Figure 1). For the second time after the Viking landers in 1976, SAM detected chlorinated organic compounds with the pyrolysis GC-QMS experiment. The detection of perchlorates salts (ClO4-) in soil at the Phoenix Landing site suggests that the chlorohydrocarbons detected could come from the reaction of organics with oxychlorines. Indeed, laboratory pyrolysis experiments have demonstrated that oxychlorines decomposed into molecular oxygen and volatile chlorine (HCl and/or Cl2) when heated which then react with the organic matter in the solid samples by oxidation and/or chlorination processes.

  1. 16 CFR 1507.2 - Prohibited chemicals. (United States)


    ... chemicals: (a) Arsenic sulfide, arsenates, or arsenites. (b) Boron. (c) Chlorates, except: (1) In colored... barium chlorate. (d) Gallates or gallic acid. (e) Magnesium (magnesium/aluminum alloys, called...

  2. Determination of chlorate and perchlorate in explosive residues of chlorate explosive by ion chromatography%离子色谱法检测氯酸盐炸药爆炸残留物中ClO-3和ClO-4

    Institute of Scientific and Technical Information of China (English)



    利用离子色谱法检测氯酸盐类炸药爆炸残留物中的ClO-3和ClO-4,采用高容量阴离子分析柱IonPac AS23、抑制型电导检测,以KOH为流动相,等度淋洗.19 min内测定样品中包含ClO-3和ClO-4在内的4种阴离子,ClO-3和ClO-4的保留时间分别为5.0 min和17.7 min,检出限(S/N=3)分别为3.0 μg/L和5.0 μg/L.将此法应用于两起爆炸案的检材测定,4种阴离子的加标回收率在94.2%~101.1%之间.

  3. 氯酸盐在龙眼生产中运用和研究现状及其生物学效应的机理探讨%Current Situation in the Research and Application of Chlorate in Longan Production and Approaches to Understanding the Mechanisms of the Biological Effects of Chlorate

    Institute of Scientific and Technical Information of China (English)

    陆洁梅; 黄旭明; 王惠聪; 张承林; 杨瑞陶; 谢亮



  4. The Improvement of the Experiment Equipment of Potassium Chlorate and Manganese Dioxider for the Preparation of Oxygen%氯酸钾和二氧化锰制备氧气实验装置的改进

    Institute of Scientific and Technical Information of China (English)

    陈浩漫; 穆旗旗; 衷明华




    Institute of Scientific and Technical Information of China (English)

    唐宁莉; 黄尚格


    基于在稀硫酸溶液中,As(Ⅲ)存在下,Os(Ⅷ)对KClO3氧化孔雀绿的褪色反应具有强烈的催化作用,提出了催化光度法测定痕量锇的新方法,其灵敏度为4.98×10-13 g/L Os(Ⅷ),测定范围为0~6 ng/12 mL,用于地质管理样中痕量锇的测定.

  6. A Preliminary Investigation of the Influences of the Application of Potassium Chlorate on the Flower Forming of Longan%施用氯酸钾对龙眼成花影响初探

    Institute of Scientific and Technical Information of China (English)



    @@ 九十年代中后期台湾、泰国已有反季节龙眼批量出口,倍受瞩目的龙眼药物催花技术又称龙眼产期调控或反季节栽培,目前在龙眼促花方面取得一定的成效.

  7. Determination of Chlorine Dioxide, Chlorine, Chlorite and Chlorate in Water by Ion Chromatography%用离子色谱法测定水中的二氧化氯、氯、亚氯酸根及氯酸根

    Institute of Scientific and Technical Information of China (English)

    田芳; 谢家理



  8. 再论氯酸钾与花炮安全生产的关系%Discussion on the Relationship of Potassium Chlorate with Safety in Production of Fireworks

    Institute of Scientific and Technical Information of China (English)




  9. Study of 10 Metal Oxides on the Thermal Decomposition of Potassium Chlorate to Yield Oxygen%10种金属氧化物对氯酸钾热分解制氧催化效果的研究

    Institute of Scientific and Technical Information of China (English)

    陈金娥; 张海容


    加热KCIO3分解制氧常使用MnO2作催化剂.实验发现:CaO,Al2O3,CuO,Fe2O3,TiO2,Nd2O3,PdO2,V2O5,Cr2O3 9种金属氧化物及无机盐MnSO4,FeCl2,FeCl3,CoCl2,ZnCl2等亦有较好的催化效果,在试剂用量、产氧量、反应速度和控制副反应等方面具有明显的优点.

  10. Analysis on the explosion fatalness of using potassium chlorate in fire powder%烟火药中使用氯酸钾的爆炸危险性分析

    Institute of Scientific and Technical Information of China (English)





    Directory of Open Access Journals (Sweden)

    Ronaldo Veloso Naves


    Full Text Available

    The efficiency of several insecticides for the control of the banana borer were tested in two kinds of traps. The cloride insecticides are most widely used but they are probably repellent to the weevil. DDT, Aldrin, Diazinon and Parathion were compared in two kinds of traps: slices of rhizome and pieces of pseudostem. The best results were obtained with Parathion in rhizome slices.

    A broca-da-bananeira ou “moleque” (Cosmopolites sordidus Germar é urna das pragas mais importantes da bananeira. A revisão de literatura mostra que os produtos clorados são os mais utilizados e recomendados no combate a essa praga, principalmente, Aldrin. O presente trabalho visou a testar inseticidas fosforados e também verificar o tipo de isca mais atrativa. A análise estatística dos dados obtidos demonstrou haver diferença significativa entre os tratamentos, entre os dois tipos de iscas, e na interação iscas x tratamento. Com base nos resultados e observações feitas durante a fase experimental, podemos tirar as seguintes conclusões: a As iscas do tipo sanduíche, feitas com pedaços de rizoma são mais atrativas do que as do tipo telha, feita de pedaços de pseudo-caule, cortados longitudinalmente; b O inseticida que apresentou melhores resultados foi o RHODIATOX (Parathion.

  12. Arabidopsis CDS blastp result: AK287911 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287911 J065213B08 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 3e-85 ...

  13. Arabidopsis CDS blastp result: AK318551 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318551 J075138M12 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 4e-27 ...

  14. Arabidopsis CDS blastp result: AK241823 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241823 J065212G21 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 1e-150 ...

  15. Arabidopsis CDS blastp result: AK243378 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243378 J100063A13 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 5e-18 ...

  16. Arabidopsis CDS blastp result: AK288351 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288351 J090024C17 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 2e-24 ...

  17. Arabidopsis CDS blastp result: AK242252 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242252 J075182G16 At1g12110.1 68414.m01402 nitrate/chlorate transporter (NRT1.1) ...(CHL1) identical to nitrate/chlorate transporter SP:Q05085 from [Arabidopsis thaliana]; contains Pfam profile: PF00854 POT family 6e-88 ...

  18. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M


    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  19. Chloriet, chloraat en bromaat in drink- en oppervlaktewater: Voorkomen, herkomst en gezondheidsaspecten

    NARCIS (Netherlands)

    Versteegh JFM; Neele J; Cleven RFMJ


    Chlorate and chlorite exist in surface water especially in the rivers Meuse and Rhine. The average concentration of chlorite and chlorate in river water varies from 10 - 40 mug/l during the six months monitoring program in 1991/1992. The concentrations are lowered during dune infiltration and afte

  20. Media for efficient generating nitrate- - nonutilizing (NIT) mutants of Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum.

    NARCIS (Netherlands)

    Rataj-Guranowska, M.; Pieczul, K.; Nowak, E.; Hiemstra, J.A.; Drapikowska, M.


    The effect of several media amended wit potassium chlorate (1.5% and 6%) on generation of nit mutants, especially nit M mutants from Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum were studied. For all species minimal medium with 6% chlorat

  1. Ultrasonic Weld Sealing of M55 Stab Detonators (United States)


    barium nitrate, and graphite Lead styphnate , tetracene, barium nitrate NOL-130 5 1. Elimination of the lacquer application with its attendant...chlorate FFFFG Magnesium and barium peroxide Boron, lead dioxide, and Viton A AIA (ferric oxide, zirconium) Potassium chlorate, sulfur, and dyes...Tungsten, barium perchlorate, and ammon- ium perchlorate Manganese, barium chromate, and lead chromate Magnesium, sodium nitrate, organic binder 75

  2. Evaluation of Alternative Causes of Widespread, Low Concentration Perchlorate Impacts to Groundwater (United States)


    for swimming pool chlorination. Bleach is commonly generated through the electrolysis of a weak brine (i.e., NaCl) solution at a pH of 10-12 via...PRODUCED (ECP) CHEMICALS 4.1 Background During the electrochemical manufacture of chemicals such as chlorate from chloride brine feedstocks, small...Background Sodium chlorate is produced electrochemically by the electrolysis of aqueous sodium chloride (NaCl) according to the following overall

  3. Study and application of sodium chlorate oxygen equipment on safety protection of pipeline construction in trench%氯酸钠氧烛装置在管道沟下作业安全防护中的应用研究

    Institute of Scientific and Technical Information of China (English)

    王江宇; 齐晨光; 汪振宇



  4. Study of the autocatalytic chlorate–triiodide reaction in acidic and neutral media

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mohammad


    Full Text Available The oxidation reaction of triiodide, I3−, by chlorate is investigated in a slightly acidic and neutral media. The reaction was verified and monitored both potentiometrically and spectrophotometrically. Generally, a slow linear decay preceded by an induction period was observed for the triiodide concentration following the addition of chlorate. The induction period is likely to be related to the time required for the generation of suitable concentrations of plausible intermediates (HIO and HIO2, which are assumed to auto-catalyse the reaction. We examined the effect of acidity and concentrations of both chlorate and triiodide on the induction time for this reaction. The acidity of the medium influenced the induction period, while the oxidation of iodide by chlorate competed with that of iodine as the medium acidity increased, making the reaction more complicated. Therefore, a suitable pH is highly recommended for studying the chlorate–triiodide reaction. A plausible mechanism involving the HIO, HIO2, and I2O species is proposed.

  5. The tropical fruit and nut collections and research activities at the USDA-ARS Pacific Basin Agricultural Research Center, Tropical Plant Genetic Resource and Disease Research unit (United States)

    In Hawaii, consistency and reliability are important factors determining the success of a crop, for example, longan generated the highest income return for the farmers among the Sapindaceae (lychee, longan and rambutan) group in 2006 because of the use of potassium chlorate for off-season production...

  6. Food safety on the farm: Movement toward the development of sustainable and environmentally compatible pre-harvest interventions for livestock producers (United States)

    Pathogenic bacteria residing in the gut of food-producing animals can contaminate meat and dairy products during processing. A chlorate-based feeding strategy specifically targeting respiratory nitrate reductases possessed by E. coli and Salmonella has shown promise in depopulating these pathogens. ...

  7. 77 FR 26071 - Revisions to the Unregulated Contaminant Monitoring Regulation (UCMR 3) for Public Water Systems (United States)


    ... fulfills EPA's obligation under SDWA by identifying 29 unregulated contaminants for monitoring during the... or the State. Changes to the rule language clarify that when identifying a representative well, the... Anion using EPA Method 300.1 (IC/Conductivity) \\6\\ or alternate SM \\7\\ or ASTM Methods: \\8\\ chlorate....

  8. New Rice Mutants(NR676 and NR827)Low in Nitrate Reduction

    Institute of Scientific and Technical Information of China (English)


    Mutants deficient in nitrate reductase(NR) were classfied into two groups,nia types are deficient in apoprotein and cnx types are lack of Mo- Co. This paper reports the characteristics of low NR mutants,which are not deficient in NR activity but 40%~60% of the NR activity of the wild type,Nipponbare. Mutants NR676 and NR827 were selected as seedings showing poor growth with nitrate as sole mitrogen source from M2 population. They exhibited chlorate resistance. Genetic analysis in the F1 and F2 indicated that chlorate resistance in the mutants was transmitted by a single recessive nuclear gene and that NR676 and NR827 were induced by a mutation at a single locus. In the F2 population,all of the seedings showing yellow green leaves were resistant to chlorate and low in NR activity. Photosynthetic rate and mRNA expression of NR676 and NR827 were lower than wild type. These results suggested that low NR activity and chlorate resistance of NR676 and NR827 were caused by a defect in photosynthetic process.

  9. Chloroxyanion residues in cantaloupe and tomatoes after chlorine dioxide gas sanitation (United States)

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

  10. Physiological and genetic description of dissimilatory perchlorate reduction by the novel marine bacterium Arcobacter sp. strain CAB. (United States)

    Carlström, Charlotte I; Wang, Ouwei; Melnyk, Ryan A; Bauer, Stefan; Lee, Joyce; Engelbrektson, Anna; Coates, John D


    A novel dissimilatory perchlorate-reducing bacterium (DPRB), Arcobacter sp. strain CAB, was isolated from a marina in Berkeley, CA. Phylogenetically, this halophile was most closely related to Arcobacter defluvii strain SW30-2 and Arcobacter ellisii. With acetate as the electron donor, strain CAB completely reduced perchlorate (ClO4(-)) or chlorate (ClO3(-)) [collectively designated (per)chlorate] to innocuous chloride (Cl(-)), likely using the perchlorate reductase (Pcr) and chlorite dismutase (Cld) enzymes. When grown with perchlorate, optimum growth was observed at 25 to 30°C, pH 7, and 3% NaCl. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) preparations were dominated by free-swimming straight rods with 1 to 2 polar flagella per cell. Strain CAB utilized a variety of organic acids, fructose, and hydrogen as electron donors coupled to (per)chlorate reduction. Further, under anoxic growth conditions strain CAB utilized the biogenic oxygen produced as a result of chlorite dismutation to oxidize catechol via the meta-cleavage pathway of aerobic catechol degradation and the catechol 2,3-dioxygenase enzyme. In addition to (per)chlorate, oxygen and nitrate were alternatively used as electron acceptors. The 3.48-Mb draft genome encoded a distinct perchlorate reduction island (PRI) containing several transposases. The genome lacks the pcrC gene, which was previously thought to be essential for (per)chlorate reduction, and appears to use an unrelated Arcobacter c-type cytochrome to perform the same function. IMPORTANCE The study of dissimilatory perchlorate-reducing bacteria (DPRB) has largely focused on freshwater, mesophilic, neutral-pH environments. This study identifies a novel marine DPRB in the genus Arcobacter that represents the first description of a DPRB associated with the Campylobacteraceae. Strain CAB is currently the only epsilonproteobacterial DPRB in pure culture. The genome of strain CAB lacks the pcrC gene found in all


    Institute of Scientific and Technical Information of China (English)

    孙洋洲; 姚沛


    介绍了以钛基体二氧化铅作为阳极,电解氯酸钠合成高氯酸钠的过程。考察了电解温度、电解液初始氯酸钠浓度及氯化钠浓度对电流效率的影响。得出了电解反应的最佳条件。%A process of electrolytic synthesis of sodium perchlorate from sodium chlorate solution by lead dioxide anode based titanium metal is introduced. The influence of temperature,the concentration of sodium chlorate and the concentration of sodium chloride on the current efficiency is investigated, and the optimum conditions of the electrolytic process are also obtained.

  12. Recovery and Biological Properties of Nitrate Non-utilizing Mutants of Rice Blast, Magnaporthe grisea

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chuan-qing; ZHOU Ming-guo


    Eleven nitrate non-utilizing (nit) mutants were recovered from six isolates of Magnaporthe grisea cultured on MM media amended with 60 g/L potassium chlorate, with a frequency of 1.42 %. Some biological properties, such as growth rate, growth biomass, cultural characters, conidial production, sexual reproduction ability, and pathogenicity were compared between nit mutants and their parent isolates. Results showed that all the nit mutants were resistant to chlorate. Some important biological properties such as the growth rate on YPSA, conidial production ability on TPSA, pathogenicity, had no significant differences between nit mutants and their parent isolates. Mating type didn't change, but perithecia production ability of fertile isolates changed significantly as compared with that of their parent isolates. Therefore, the nit can be used as a genetic marker to study the genetics such as pathogenicity, fungicide resistance in Magnaporthe grisea.

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

    Directory of Open Access Journals (Sweden)

    C. Lasagna


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

  14. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR (United States)

    Lužnik, Janko; Pirnat, Janez; Trontelj, Zvonko


    A mini-thermometer based on the 35Cl nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO3 and NaClO3 was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm3 active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR spectrometer input tank circuit, (b) to use a single crystal of KClO3 or NaClO3 (of 1-2 mm3 size) in one coil as a mini-thermometer with a resolution of 0.03 K and (c) to construct a system for measuring temperature gradients when the spatial coordinates of each chlorate single crystal within an individual coil are known.

  15. The Detection of Evolved Oxygen from the Rocknest Eolian Bedform Material by the Sample Analysis at Mars(SAM) instrument at the Mars Curiosity Landing Site (United States)

    Sutter, B.; Archer, D.; Ming, D.; Eigenbrode, J. L.; Franz, H.; Glavin, D. P.; McAdam, A.; Mahaffy, P.; Stern, J.; Navarro-Gonzalex, R.; McKay, C.


    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detected an O2 gas release from the Rocknest eolain bedform (Fig. 1). The detection of perchlorate (ClO4-) by the Mars Phoenix Lander s Wet Chemistry Laboratory (WCL) [1] suggests that perchlorate is a possible candidate for evolved O2 release detected by SAM. The perchlorate would also serve as a source of chlorine in the chlorinated hydrocarbons detected by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [2,3]. Chlorates (ClO3-) [4,5] and/or superoxides [6] may also be sources of evolved O2 from the Rocknest materials. The work objectives are to 1) evaluate the O2 release temperatures from Rocknest materials, 2) compare these O2 release temperatures with a series of perchlorates and chlorates, and 3) evaluate superoxide O2- sources and possible perchlorate interactions with other Rocknest phases during QMS analysis.

  16. Kinetics and mechanism study on chlorine dioxide generation with hydrogen peroxide%过氧化氢法制备二氧化氯反应动力学及机理研究

    Institute of Scientific and Technical Information of China (English)

    朱明新; 黄辉; 董娴; 沈丽娜; 徐炎华


    The reaction between hydrogen peroxide and sodium chlorate in presence of aqueous sulfuric acid was studied at various temperatures and molar concentrations of hydrogen peroxide, chlorate and sulfuric acid. The reaction rate law was established by analyzing the consumption of chlorate or hydrogen peroxide. Reaction order is found 0. 5 and 1 with respect to hydrogen peroxide and chlorate concentration, respectively. Reaction order is found about 5. 99 with respect to molar concentration of sulfuric acid, but it reduces to 1. 64 when acidity func-tion(h- ) , is substituted in place of molar concentration. The reaction is a process of leat absorption and the activation energy is about 105kJ/mol. Reaction mechanism shows it is a self-catalyze reaction.%通过改变反应温度和物料浓度,研究过氧化氢与氯酸钠在硫酸溶液中的反应过程,获得宏观反应动力学方程,并对其反应机理进行了深入探讨.研究表明过氧化氢法制备二氧化氯反应过程中过氧化氢的反应级数为0.5,氯酸钠为1,对于硫酸摩尔浓度的反应级数为5.99,当用酸度函数(h_)代替硫酸摩尔浓度时反应级数则下降为1.64;该反应是吸热过程,反应活化能约为105kJ/mol;机理分析表明该反应是自催化反应过程.

  17. Validation of a Novel Bioassay for Low-level Perchlorate Determination (United States)


    chamber using the plate reader bioassay format. 3. IC analysis for common anions showed that nitrate was present in SPE effluents at about the same...Compare Benchtop Bioassay Field Kit Results to Site’s Reference Method Results 13 3.3 Qualitative Performance Objective: Field Kit Ease of Use... Nitrate , Sulfate, Fluoride, Nitrite, Bromide, Chlorate, and Phosphate 143 Appendix I: ICPMS Characterization of Groundwater Sources and SPE Eluates

  18. Portable Home Welder (United States)


    Pyronetics, Inc. manufactured a small, do-it-yourself welding torch which weighs only 7 pounds, gives a 5,000 degree Farenheit flame, and costs only $40.00. This resulted from information provided by a NASA Industrial Application Center at the University of Southern California. The center provided information on chlorate candles, unique in that they generate oxygen while burning. A retrospective search uncovered information on composition, hazards, applications, manufacturers, and shipping regulations.

  19. Regulation of Breast Carcinoma Growth and Neovascularization by Peptide Sequences in Thromospondin (United States)


    10-43) 0/8 Prostate 1/2 17 0/2 Breast 7/8 15 (8-29) 3/8 2.1 (1.1-2.7) Free and polysucrose-conjugated forms of peptide 476 (ri-amKRAKQAGGWSHWSPWSSCac...medium contain- taxis of MDA-MB-435 cells to TSP1 is also primarily dependent ing 1 mg/ml BSA with or without chlorate at the indicated concentra- on

  20. An unusual case of reversible acute kidney injury due to chlorine dioxide poisoning. (United States)

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


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

  1. Electrochemical and Integrated Process Opportunities for On-Site/On-Demand Generation of Chlorine Dioxide - Final Report - 08/02/1996 - 08/01/1999

    Energy Technology Data Exchange (ETDEWEB)

    Tatarchuk, Bruce J.; Krishnagopalan, G.; Nickell, Ryan A.


    Due to continued evidence of environmental harm from elemental chlorine bleaching, the nation's paper industry continues to search for cost effective alternative bleaching. A practical and cost effective bleaching alternative is chlorine dioxide manufactured entirely from sodium chlorate. Sodium chlorate is produced by the electrolysis of brine in an undivided cell with steel plate cathodes and dimensionally stable anodes. Although the overpotential at the anode is only 50 mV, the cathodic overpotential is 940 mV. Thus, nearly one volt of electricity is wasted in driving hydrogen evolution at the cathode. Auburn University's Center for Microfibrous Materials Manufacturing has demonstrated that high performance, three dimensional, microfibrous electrodes can improve the performance of capacitors, batteries, hybrid power cells, and electrolysis electrodes in a variety of applications. The goal of this research was to apply this technology to a chlorate cell's cathode and reduce the overpotential between 200 and 400 mV. An economic analysis of the industry has shown that for every 100 mV reduction in overpotential, $100 per square meter of electrode can be saved annually. Due to their enhanced surface area over plates, corrosion of microfibrous electrodes is a major issue in this research. Samples based on chromium protection (i.e. stainless steel) have proved unfeasible for chlorate application. However, samples based on stainless steel and nickel show dramatic performance improvements over industry status quo in chlor-alkali application. Building microfibrous electrodes on a titanium base protected with a silver coating alleviates the corrosion problem and provides 100 mV or more of overpotential reduction. Further reduction is realized by impregnating silver-titanium microfibrous mesh with a PVDF binder and dispersed platinum on activated carbon. The resulting electrodes are mechanically sound, active towards hydrogen evolution, and hold promise for

  2. Disinfection aboard cruise liners and naval units: formation of disinfection by-products using chlorine dioxide in different qualities of drinking water. (United States)

    Ufermann, Petra; Petersen, Hauke; Exner, Martin


    The world-wide deployment of cruise liners and naval units has caused an increased need for the disinfection of drinking water. The main cause for this is the unknown quality of drinking water in foreign harbours--besides the formation of bio-films due to the climatically disadvantageous conditions in the operational area. Water conduits on board are currently disinfected with calcium hypochlorite in case of microbiological contamination. Chemical and physical analyses after disinfection with calcium hypochlorite have shown that organic by-products consisting of trihalomethanes develop in considerable amounts during disinfection. Furthermore, the method is susceptible to handling errors and thus often leads to insufficient disinfection results. Hitherto, the use of other disinfection methods allowed by government regulations, especially chlorine dioxide, is not widely spread. Unlike disinfection with calcium hypochlorite, chlorine dioxide does not lead to the formation of trihalomethanes. Typical disinfection by-products (DBP) are the anions chlorite and chlorate, which are formed in oxidative processes. The formation conditions of these anions have not yet been elucidated. For this reason, the probability of the generation of inorganic by-products after disinfection with chlorine dioxide has been determined, and their occurrence in drinking water on board has been examined with respect to a possible correlation between water quality and the formation of chlorate and chlorite. Therefore, a chromatographic method was developed and validated in order to determine the periodical development of chlorate and chlorite from chorine dioxide in purified water at different pH-values as well as in actual drinking water samples from water conduits on board. The formation of the by-products chlorite and chlorate after disinfection with chlorine dioxide is influenced neither by pH-value nor by chemical properties of the disinfected water. Considering the examined conditions

  3. Federal and State Laws and Safety Considerations Relating to Fireworks in the United States. (United States)


    Picrates or picric acid . 7. Gallates or gallic acid . 8. Chlorates, except those of alkali and earth metals. 9. Boron. 10. Titanium, except in particle...handling and full operation of the (d) Gallates or gallic acid . device, or shall consist of an integral (e) Magnesium (magnesium/alumi- section of the...KEY WORDS (Continue on reverse aide it noceeary and Identity by block number) Display fireworks State laws and regulations Sale and use Common

  4. Validation of Chlorine and Oxygen Isotope Ratio Analysis To Differentiate Perchlorate Sources and To Document Perchlorate Biodegradation (United States)


    ferrous iron, sulfite, or thiosulfate (Brown and Gu, 2006; Urbansky, 2002). ClO4- reduction can be mediated by some catalysts , including ruthenium(II... nitrate reduction by denitrifying bacteria. Limnol. Oceanography 53:2533-2545. Granger, J.; Sigman, D.M.; Needoba, J.A.; Harrison, P.J. 2004. Coupled... nitrate reduction pathways are separately induced in the perchlorate-respiring bacterium Dechlorosoma sp. KJ and the chlorate-respiring bacterium

  5. Nitrate Uptake into Barley (Hordeum vulgare) Plants 1 (United States)

    Deane-Drummond, Celia E.; Glass, Anthony D. M.


    Evidence is presented that chlorate is an extremely good analog for nitrate during nitrate uptake by intact barley (Hordeum vulgare cv. Fergus) roots. The depletion of ClO3− or NO3− from uptake media over 2 to 6 hours by seedlings was found to be dependent on combined NO3− plus ClO3− concentrations, and total anion uptake was equivalent at different NO3−/ClO3− ratios. After loading barley seedlings with 36ClO3− for 6 hours, kinetic parameters were derived from the analysis of efflux of [36Cl] chlorate into unlabeled solution. On the basis of this analysis, the half times for exchange for the cytoplasmic and vacuolar phases were 17 minutes and 20 hours, respectively. Data pooled from a number of different experiments were used to calculate kinetic constants (Km and Vmax) for 36ClO3− influx into barley roots at different external ClO3−/NO3− ratios, using short (10 minutes) influx times. There appeared to be no discrimination by the root cells between ClO3− and NO3−. Lineweaver-Burk analysis of the interaction between nitrate and chlorate were characteristic of competitive inhibition at low nitrate concentrations (0-0.5 mm). At higher concentrations, in the range of >1 mm, similar interactions between these ions were evident. PMID:16662478

  6. Genome analysis and physiological comparison of Alicycliphilus denitrificans strains BC and K601T

    Energy Technology Data Exchange (ETDEWEB)

    Oosterkamp, Margreet J. [Wageningen University and Research Centre, The Netherlands; Veuskens, Teun [Wageningen University and Research Centre, The Netherlands; Saia, Flavia Talarico [Wageningen University and Research Centre, The Netherlands; Weelink, Sander A.B. [Wageningen University and Research Centre, The Netherlands; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Daligault, Hajnalka E. [Los Alamos National Laboratory (LANL); Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Langenhoff, A. M. [Deltares, The Netherlands; Gerritse, Jan [Deltares, The Netherlands; Van Berkel, Willem J. H. [Wageningen University and Research Centre, The Netherlands; Pieper, Dietmar [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Junca, Howard [CorpoGen, Bogota Colombia; Smidt, Hauke [Wageningen University and Research Centre, The Netherlands; Schraa, Gosse [Wageningen University and Research Centre, The Netherlands; Davids, Mark [Wageningen University and Research Centre, The Netherlands; Schaap, Peter J [Wageningen University and Research Centre, The Netherlands; Plugge, Caroline M. [Wageningen University and Research Centre, The Netherlands; Stams, Alfons J. M. [Wageningen University and Research Centre, The Netherlands


    The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far.

  7. Distribution, Identification, and Quantification of Residues after Treatment of Ready-To-Eat Salami with (36)Cl-Labeled or Nonlabeled Chlorine Dioxide Gas. (United States)

    Smith, David J; Giddings, J Michael; Herges, Grant R; Ernst, William


    When ready-to-eat salami was treated in a closed system with (36)Cl-labeled ClO2 (5.5 mg/100 g of salami), essentially all radioactivity was deposited onto the salami. Administered (36)ClO2 was converted to (36)Cl-chloride ion (>97%), trace levels of chlorate (<2%), and detectable levels of chlorite. In residue studies conducted with nonlabeled ClO2, sodium perchlorate residues (LOQ, 4 ng/g) were not formed when reactions were protected from light. Sodium chlorate residues were present in control (39.2 ± 4.8 ng/g) and chlorine dioxide treated (128 ± 31.2 ng/g) salami. If sanitation occurred under conditions of illumination, detectable levels (3.7 ± 1.5 ng/g) of perchlorate were formed along with greater quantities of sodium chlorate (183.6 ± 75.4 ng/g). Collectively, these data suggest that ClO2 is chemically reduced by salami and that slow-release formulations might be appropriate for applications involving the sanitation of ready-to-eat meat products.

  8. Distribution and chemical fate of ³⁶Cl-chlorine dioxide gas during the fumigation of tomatoes and cantaloupe. (United States)

    Smith, D J; Ernst, W; Giddings, J M


    The distribution and chemical fate of (36)Cl-ClO2 gas subsequent to fumigation of tomatoes or cantaloupe was investigated as were major factors that affect the formation of chloroxyanion byproducts. Approximately 22% of the generated (36)Cl-ClO2 was present on fumigated tomatoes after a 2 h exposure to approximately 5 mg of (36)Cl-ClO2. A water rinse removed 14% of the radiochlorine while tomato homogenate contained ∼63% of the tomato radioactivity; 24% of the radiochlorine was present in the tomato stem scar area. Radioactivity in tomato homogenate consisted of (36)Cl-chloride (≥80%), (36)Cl-chlorate (5 to 19%), and perchlorate (0.5 to 1.4%). In cantaloupe, 55% of the generated (36)Cl-ClO2 was present on melons fumigated with 100 mg of (36)Cl-ClO2 for a 2 h period. Edible cantaloupe flesh contained no detectable radioactive residue (LOQ = 0.3 to 0.4 μg/g); >99.9% of radioactivity associated with cantaloupe was on the inedible rind, with <0.1% associated with the seed bed. Rind radioactivity was present as (36)Cl-chloride (∼86%), chlorate (∼13%), and perchlorate (∼0.6%). Absent from tomatoes and cantaloupe were (36)Cl-chlorite residues. Follow-up studies have shown that chlorate and perchlorate formation can be completely eliminated by protecting fumigation chambers from light sources.

  9. Chemical Control of Pennesetum Purpureum Laboratory Trials

    Directory of Open Access Journals (Sweden)

    B.N Tripathi


    Full Text Available Dichloral urea, diethyl chloracetamide, nitrourea, chloralhydrate, sodium trichloroacetate, sodium borate, ammonium thiocynate, sodium arsenite, arsenic oxide-sulphuric acid mixture, sodium chlorate, maleic hydrazide and the salts containing inorganic ions Cu/sup 2+/, Co/sup 2+/, MoO/sub 4//sup 2-/ and Zn/sup 2+/ were tested in experimental plots for their phytotoxic activity on a hybrid variety of Pennesetum purpureum. Sodium borate (2500 Kg/hectare, Sodium arsenite (250 Kg/hectare and sodium chlorate (1000 Kg/hectare through soil and ammonium thiocyanate (100 Kg/hectare through direct spray function as growth retardants. Arsenic oxide-sulphuric acid (100 : 300 Kg/hectare spray kills the existing leaves. Sodium chlorate (250 Kg/hectare spray exerts phytocidal action on young plants (3 weeks. Maleic hydrazide (50 Kg/hectare exerts permanent growth suppressant action on older plants (height >=1 m and kills the existing leaves of younger plants (height=<0.5 m. Copper sulphate (100 Kg/hectare induces partial drying of existing leaves and cobalt sulphate in the same dose induces yellowing of leaves extending the period of growth beyond the season of maximum growth of the control. Ammonium molybdate and Zinc acetate in the same dose do not exert any perceptible effect.

  10. Contact Electrification of Regolith Particles and Chloride Electrolysis: Synthesis of Perchlorates on Mars (United States)

    Tennakone, K.


    Contact electrification of chloride-impregnated martian regolith particles due to eolian agitation and moisture condensation on coalesced oppositely charged grains may lead to spontaneous electrolysis that generates hypochlorite, chlorite, chlorate, and perchlorate with a concomitant reduction of water to hydrogen. This process is not curtailed even if moisture condenses as ice because chloride ionizes on the surface of ice. Limitations dictated by potentials needed for electrolysis and breakdown electric fields enable estimation of the required regolith grain size. The estimated dimension turns out to be of the same order of magnitude as the expected median size of martian regolith, and a simple calculation yields the optimum rate of perchlorate production.

  11. 危险货物介绍(30)%Introduction to Dangerous Goods (30)

    Institute of Scientific and Technical Information of China (English)



    @@ 俗称:白药粉,白药,洋硝,盐酸加里 英文名称:Potassium Chlorate 分子式:KCLO3 特性:为透明无色结晶或白色粉末.味咸而凉,可与铵的化合物、易燃物或细碎金属粉末组成爆炸性混合物.与易燃物的混合物对摩擦敏感,与硫酸接触易着火或爆炸.


    Institute of Scientific and Technical Information of China (English)

    仇佩虹; 林丽; 叶晓霞; 叶小琴


    A new catalytic kinetic method for determining trace selenium(Ⅳ) was described.Se(Ⅳ) can catalyze the discolouring of 2-(5-Bromo-2-Pyridylazo)-5-diethylaminophenol(5-Br-PADAP) by potassium chlorate in hydrochloric acid medium.The detection limit for Se(Ⅳ) is 5.7×10-5μg/ml.The linear range of determination is 0~0.4μg/25ml Se(Ⅳ).Satisfactory results may be obtained by direct determination of trace Se(Ⅳ) in human hair.

  13. Evidence for the distribution of perchlorates on Mars (United States)

    Clark, Benton C.; Kounaves, Samuel P.


    Various Mars missions have detected Cl atoms, chlorides and perchlorates in martian surface materials. The global soils, in particular, always contain significant levels of observable Cl. Direct evidence points to this Cl being in the form of both chlorides and perchlorates, and possibly also chlorates and other oxychlorines. The most widespread measurements have been of Cl atoms, and cannot discern the chemical form. However, from separate evidence of perchlorate obtained at high latitudes (Phoenix lander) and low latitudes (Curiosity rover), it is likely that perchlorates are widespread, albeit in varying proportions relative to the total amount of ubiquitous Cl.

  14. Aquatic macro algae of a region under Almirante Alvaro Alberto nuclear power plant influence. I. Spatial seasonal evaluation; Macroalgas marinhas da regiao sob influencia da Central Nuclear Almirante Alvaro Alberto (CNAAA), Saco de Piraquara de Fora, Angra dos Reis, RJ, Brasil. I. Avaliacao espaco-temporal

    Energy Technology Data Exchange (ETDEWEB)

    Pedrini, A.G. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)]|[Universidade Santa Ursula, Rio de Janeiro, RJ (Brazil). Centro de Ciencias Biologicas; Cassano, V.; Coelho, L.G.; Labronici, G.J. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia


    Marine macro algae from the area which is under in fluence of the heated and chlorate liquid effluent to the CNAAA were observed (1981-1983) at 3 collection points: Pingo Dagua, Velho Beach, discharge point. A total of 121 taxa were found: 29 Chlorophyta, 26 Phaeophyta and 66 Rhodophyta. The spring season was the richest in taxa (78) while autumn was the poorest (85). Overall, the data suggest that the point A (Pingo Dagua) macro algae community (which is similar to the discharge point (0,80) is adequate for the control of the CNAAA effluent impact ad Piraquara de Fora. (author). 11 refs, 5 figs, 1 tab.

  15. Problem Definition Studies on Potential Environmental Pollutants. 6. Preliminary Assessment of Environmental Effects of Seven Substances Used in Pyrotechnic Compositions at Pine Bluff Arsenal (United States)


    Dextrin Red -- 85 ...... 15 Yellowa 65 -- 35 --.... Greena 20 -- 10 70 .... Violet -- 20 -- -- 80 -- a. Mil.Spec. not given. TABLE 4. COMPOSITION OF...Potassium chlorate 2,234,000 22,300 Sulfur 893,000 8,900 Dextrin 151,000 1,500 Oil 18,000 180 Unknown 563,000 5,600 a. Calculations are based on pure...hazard; sulfur, essentially harmless in itself, slowly degrades chemically and biochemically to rontoxic products; dextrin (a starch derivative used in

  16. A bioinspired iron catalyst for nitrate and perchlorate reduction. (United States)

    Ford, Courtney L; Park, Yun Ji; Matson, Ellen M; Gordon, Zachary; Fout, Alison R


    Nitrate and perchlorate have considerable use in technology, synthetic materials, and agriculture; as a result, they have become pervasive water pollutants. Industrial strategies to chemically reduce these oxyanions often require the use of harsh conditions, but microorganisms can efficiently reduce them enzymatically. We developed an iron catalyst inspired by the active sites of nitrate reductase and (per)chlorate reductase enzymes. The catalyst features a secondary coordination sphere that aids in oxyanion deoxygenation. Upon reduction of the oxyanions, an iron(III)-oxo is formed, which in the presence of protons and electrons regenerates the catalyst and releases water.

  17. Problem Definition Studies on Potential Environmental Pollutants. II. Physical, Chemical, Toxicological, and Biological Properties of 16 Substances (United States)


    lack of complete data indicates the need for further studies to accurately evaluate the potential toxicity of PulP . Re- commendations for further...Strzyzowski, C., "Rapid Fatal Poisoning by Sodiuin Chlorate," Ann. rntd. legale criminal, police sci., 11, 528-537 (1931). 51. Oliver , J. S., H. Smith and A. A...3uttrel I, 14., "Collaborative Study of a Colorimetric Method for’ Determining Arsenic Residues in Red Meat and Poultry ".. Journal ). ?A .(.A.C., 56, 1144

  18. [Oxygen in the field hospitals: current experience in the military health service]. (United States)

    Rouvier, B; Dupeyron, C; Carpentier, J P; Evrard, P


    A fifty per cent oxygen ratio locks quite sufficient for putting at sleep war wounded patient. After the present time, every french field surgical structures are equipped with oxygen extractors. Furthermore, those teams have at heir disposal for several years, oxygen generators, working with sodium chlorate candels. Those one can fill oxygen cylinders (3.5 l at 90 or 150 bars), providing pure oxygen, which will ever be essential under exceptional conditions. During war period, the supply difficulties demand to have at disposal two different production capabilities for oxygen administration.

  19. Synthesis of semiconductor polymers by inductive plasma; Sintesis de polimeros semiconductores por plasmas inductivos

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, G.; Cruz, G.; Olayo, M.G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Morales, J. [UAM-I, 09340 Mexico D.F. (Mexico)


    When carrying out the synthesis of semiconductor polymers by plasma it is important to consider the electric arrangement of the discharge since this it influences in the distribution of the energy of the particles in the reactor. The main electric arrangements in those that are developed the brightness discharges of radio frequency are resistive, capacitive and inductive. In the Laboratory of Materials processing by plasma of the ININ its have been worked different synthesis of polymers with resistive arrangements with good results. In this work the results of the synthesis and characterization of poly aniline and chlorate polyethylene by inductive plasma are presented. (Author)

  20. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR



    A mini-thermometer based on the ▫$^{35}Cl$▫ nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO▫$_3$▫ and NaClO▫$_3$▫ was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm▫$^3$▫ active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR ...

  1. Vegetative compatibility and RFLP analysis of Colletotrichum destructivum isolates from alfalfa and red clover

    Directory of Open Access Journals (Sweden)

    Vasić Tanja


    Full Text Available A total of 17 isolates of Colletotrichum from alfalfa (Medicago sativa L. and red clover (Trifolium pratense L. plants with anthracnose symptoms were collected from 11 districts in Serbia during 2005-2010 and tested for variability in vegetative compatibility groups (VCGs and restriction fragment length polymorphisms (RFLP. Nitrate nonutilising (nit mutants were isolated from each of investigated C. destructivum isolates by selecting chlorate-resistant sectors on medium with chlorate. The isolates were grouped in five VCGs while one isolate was self-incompatible. No relationship was found between VCGs and geographical origin of the isolates. Restriction Fragment Length Polymorphism (RFLP analysis of a 900 bp intron of the glutamine synthetase (GS gene revealed a unique polymorphic profile of C. destructivum isolates, distinct from the profiles of other Colletotrichum species. An identical profile was produced for all C. destructivum isolates, regardless of their host and geographical origin. PCR-RFLP failed to detect some the Serbian C. destructivum isolates. [Projekat Ministarstva nauke Republike Srbije, br. TR31057

  2. 海砂对混凝土耐久性的影响及其淡化处理%Effect of sea sand on concrete durability and the desalination

    Institute of Scientific and Technical Information of China (English)

    贺烽; 韩继先


    近年来,随着河砂开采的限制和资源的匮乏,海砂在沿海地区建筑行业中的使用越来越普遍.介绍了我国的海砂资源情况和海砂性能特征,并分析了海砂中盐类尤其是氯盐和杂质对混凝土耐久性能的影响.海砂通过淡化处理,可以很好地去除其中有害的盐类和杂质,从而可确保淡化后的海砂在建筑工程中的安全可靠应用.%In recent years, with the restricted mining and resource-poor of river sand, the utilization of sea sand in construction indus?try of coastal area is more and more common. China sea sand resource and performance characteristics are introduced, and the effects of chlorate and impurities in sea sand on concrete durability are analysed. By desalinating the harmful chlorate and impurities in sea sand can be moved effectively, which guarantees safe and reliable application of desalted sea sand in construction engineering.

  3. The measures to improve conversion rate of chlorine dioxide in methanol method process%提高甲醇法二氧化氯制备工艺转化率的措施

    Institute of Scientific and Technical Information of China (English)

    徐萃声; 詹磊; 黄丙贵


    在强酸性环境下,甲醇可以与氯酸钠发生氧化还原反应,氯酸钠由此被还原而产生二氧化氯,人们将这种二氧化氯制备方法称之为甲醇法。纸浆漂白甲醇法二氧化氯制备系统国产化已经实现,目前已成功运行多套系统。本文分析了影响纸浆漂白甲醇法二氧化氯系统工艺转化率的相关因素,并结合生产实际提出了相应的改进措施。%Methanol can make oxidation-reduction reaction with sodium chlorate under strong acid situation. Sodium chlorate is restored to make chlorine dioxide, which is called methanol method to prepare chlorine dioxide. The methanol method for chlorine dioxide preparation has been localized successfully, which has been well proven in many projects in bleaching plant in pulp industry. In this article were analyzed the relating factors of conversion rate of chlorine dioxide which is used in pulp bleaching process, and was put forward the corresponding improving measures combined with the production practice.

  4. Occurrence of persistent pollutants in soils, waters and firns of the Pirin mountains of Bulgaria; Persistente organische Schadstoffe in Boeden, Gewaessern und in Firn der Region noerdliche Piringebirge (Bulgarien)

    Energy Technology Data Exchange (ETDEWEB)

    Grunewald, K. [Technische Univ. Dresden (Germany). Inst. fuer Geographie; Schmidt, W. [DVGW - Technologiezentrum Wasser, Karlsruhe, TZW Aussenstelle Dresden (Germany)


    Systematic environmental screenings are still the exception in South-Eastern Europe. Especially, there is a decisive lack of information concerning the occurrence and behaviour of xenobiotic and toxic compounds like volatile- and non volatile halogenated organics, suppressed by the surrogate AOX, synthetic chelating agents, pesticides, like DDT as well as chlorate in the biosphere. The analysis of soils, waters, and firns of a representative area in Bulgaria, the Pirin mountains, indicate a relatively low back ground pollution. The accumulation of the xenobiotics in this high mountain region is recognised to be low. Nevertheless, traces of pesticides and chelating agents like EDTA and NTA in ice (firns) and soils were found. The surrogate AOX should be a parameter, suitable for routine environmental screenings of such areas. (orig.) [German] Systematische Umweltuntersuchungen stellen in Suedosteuropa noch eine Ausnahme dar. Dies betrifft insbesondere die Analyse organischer Schadstoffe, die innerhalb der Biosphaere zu toxischen Wirkungen fuehren koennen. In einer repraesentativen Region in Suedwest-Bulgarien wurden Boden-, Firn- und Wasserproben auf AOX, CKW, Chlorat, synthetische Komplexbildner, Insektizide und Herbizide untersucht. Die Hintergrundbelastung der analysierten Stoffe in Boeden und Waessern ist relativ niedrig. Eine vermutete Akkumulation persistenter organischer Chemikalien im Hochgebirge Pirin wurde nur teilweise bestaetigt. Nachgewiesen wurden Insektizidrueckstaende und die synthetischen Komplexbildner EDTA und NTA in Firnproben sowie AOX in Substratmaterial. AOX bietet sich als Parameter zur Umweltueberwachung in der Region an. Die Analyse weiterer POPs steht noch an. (orig.)

  5. Unusual inherent electrochemistry of graphene oxides prepared using permanganate oxidants. (United States)

    Eng, Alex Yong Sheng; Ambrosi, Adriano; Chua, Chun Kiang; Saněk, Filip; Sofer, Zdeněk; Pumera, Martin


    Graphene and graphene oxides are materials of significant interest in electrochemical devices such as supercapacitors, batteries, fuel cells, and sensors. Graphene oxides and reduced graphenes are typically prepared by oxidizing graphite in strong mineral acid mixtures with chlorate (Staudenmaier, Hofmann) or permanganate (Hummers, Tour) oxidants. Herein, we reveal that graphene oxides pose inherent electrochemistry, that is, they can be oxidized or reduced at relatively mild potentials (within the range ±1 V) that are lower than typical battery potentials. This inherent electrochemistry of graphene differs dramatically from that of the used oxidants. Graphene oxides prepared using chlorate exhibit chemically irreversible reductions, whereas graphene oxides prepared through permanganate-based methods exhibit very unusual inherent chemically reversible electrochemistry of oxygen-containing groups. Insight into the electrochemical behaviour was obtained through cyclic voltammetry, chronoamperometry, and X-ray photoelectron spectroscopy experiments. Our findings are of extreme importance for the electrochemistry community as they reveal that electrode materials undergo cyclic changes in charge/discharge cycles, which has strong implications for energy-storage and sensing devices.

  6. Characterisation of silver nanoparticles produced by three different methods based on Borohydride reducing agent

    Directory of Open Access Journals (Sweden)

    Hani Ramli Roslinda


    Full Text Available This work reports the preparation and characterisation of silver nanoparticles (AgNPs through chemical reduction method with three different procedures denote as modified Mulfinger’s Method, Mulfinger’s Method and Malina’s Method. The yellow colloidal solution were characterised and analysed using Field Emission Scanning Electron Microscopy (FESEM, Energy Dispersive X-ray Spectroscopy (EDS, X-Ray Diffraction (XRD. FESEM and EDS analyses confirmed that the formation of AgNPs in Malina’s Method with highest yield of silver (Ag, 67.39 % weight as compared to Mulfinger’s and modified Mulfinger’s Method. The peaks in XRD pattern for Malina’s Method are in good agreement with face-centered-cubic form of metallic silver while modified Mulfinger’s Method and Mulfinger’s Method XRD pattern suggest the halite/sodium chlorate and silver chlorate peaks respectively. Malina’s Method is found to be a suitable method to study AgNPs.

  7. Measurement of temperature and temperature gradient in millimeter samples by chlorine NQR

    Energy Technology Data Exchange (ETDEWEB)

    Luznik, Janko; Pirnat, Janez; Trontelj, Zvonko [Institute of Mathematics, Physics and Mechanics, Ljubljana (Slovenia)


    A mini-thermometer based on the {sup 35}Cl nuclear quadrupole resonance (NQR) frequency temperature dependence in the chlorates KClO{sub 3} and NaClO{sub 3} was built and successfully tested by measuring temperature and temperature gradient at 77 K and higher in about 100 mm{sup 3} active volume of a mini Joule-Thomson refrigerator. In the design of the tank-circuit coil, an array of small coils connected in series enabled us (a) to achieve a suitable ratio of inductance to capacity in the NQR spectrometer input tank circuit, (b) to use a single crystal of KClO{sub 3} or NaClO{sub 3} (of 1-2 mm{sup 3} size) in one coil as a mini-thermometer with a resolution of 0.03 K and (c) to construct a system for measuring temperature gradients when the spatial coordinates of each chlorate single crystal within an individual coil are known. (orig.)

  8. The use of chemicals for fireworks

    Energy Technology Data Exchange (ETDEWEB)

    Lancaster, R. [Kimbolton Fireworks Limited (United Kingdom)


    The history of chemicals that over time have become the fundamental building blocks of pyrotechnic compositions, and newer materials that are part of many of today's fireworks formulations, are discussed. The relationship between fireworks and the discovery of gunpowder is revisited as an important event in the origin of fireworks. While charcoal and potassium chlorate are the principal ingredients, salts of antimony, arsenic mercury, mica, borax, some lead compounds and zinc filings, along with powdered glass and porcelain, also have been tried at various times and with varying degrees of success. Nitrates of strontium, barium and sodium have been used since the earliest times in the history of fireworks to produce colors, but potassium chlorate, mixed with sulphur and sugar provided the lifting powder that made possible the production of stars, although it also produced some very bad explosions throughout history. In more recent times, chlorinated compounds, magnesium and especially aluminum, have added considerable brilliance to fireworks. The problem of corrosion, hence limited shelf-life, however, continues to be a challenge. Reference is also made to the increasing volume of regulation in Western Europe that is pushing European fireworks manufacturers to extinction. 5 refs.

  9. Allelic differences in Medicago truncatula NIP/LATD mutants correlate with their encoded proteins' transport activities in planta. (United States)

    Salehin, Mohammad; Huang, Ying-Sheng; Bagchi, Rammyani; Sherrier, D Janine; Dickstein, Rebecca


    Medicago truncatula NIP/LATD gene, required for symbiotic nitrogen fixing nodule and root architecture development, encodes a member of the NRT1(PTR) family that demonstrates high-affinity nitrate transport in Xenopus laevis oocytes. Of three Mtnip/latd mutant proteins, one retains high-affinity nitrate transport in oocytes, while the other two are nitrate-transport defective. To further examine the mutant proteins' transport properties, the missense Mtnip/latd alleles were expressed in Arabidopsis thaliana chl1-5, resistant to the herbicide chlorate because of a deletion spanning the nitrate transporter AtNRT1.1(CHL1) gene. Mtnip-3 expression restored chlorate sensitivity in the Atchl1-5 mutant, similar to wild type MtNIP/LATD, while Mtnip-1 expression did not. The high-affinity nitrate transporter AtNRT2.1 gene was expressed in Mtnip-1 mutant roots; it did not complement, which could be caused by several factors. Together, these findings support the hypothesis that MtNIP/LATD may have another biochemical activity.

  10. Method and apparatus for producing chlorine dioxide

    Energy Technology Data Exchange (ETDEWEB)

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


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

  11. Chlorine dioxide and hemodialysis

    Energy Technology Data Exchange (ETDEWEB)

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


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

  12. Formation of disinfection by-products after pre-oxidation with chlorine dioxide or ferrate. (United States)

    Yang, Xin; Guo, Wanhong; Zhang, Xing; Chen, Feng; Ye, Tingjin; Liu, Wei


    The effect of pre-oxidation with chlorine dioxide (ClO2) or ferrate (Fe(VI)) on the formation of disinfection by-products (DBPs) during chlorination or chloramination was tested with natural waters from 12 sources (9 surface waters, 1 groundwater, and 2 wastewater effluents). DBPs investigated included trihalomethanes (THM), chloral hydrate (CH), haloketones (HK), haloacetonitriles (HAN) and trichloronitromethane (TCNM), chlorite and chlorate. Chlorite and chlorate were found in the ClO2-treated waters. Application of 1 mg/L ClO2 ahead of chlorination reduced the formation potential for THM by up to 45% and the formation of HK, HAN and TCNM in most of the samples. The CH formation results were mixed. The formation of CH and HK was enhanced with low doses of Fe(VI) (1 mg/L as Fe), but was greatly reduced at higher doses (20 mg/L Fe). Fe(VI) reduced the formation of THM, HAN and TCNM in most of the samples. Reduced potential for the formation of NDMA was observed in most of the samples after both ClO2 and Fe(VI) pre-oxidation.

  13. Chloroxyanion Residues in Cantaloupe and Tomatoes after Chlorine Dioxide Gas Sanitation. (United States)

    Smith, D J; Ernst, W; Herges, G R


    Chlorine dioxide gas is effective at cleansing fruits and vegetables of bacterial pathogens and(or) rot organisms, but little data are available on chemical residues remaining subsequent to chlorine gas treatment. Therefore, studies were conducted to quantify chlorate and perchlorate residues after tomato and cantaloupe treatment with chlorine dioxide gas. Treatments delivered 50 mg of chlorine dioxide gas per kg of tomato (2-h treatment) and 100 mg of gas per kg of cantaloupe (6-h treatment) in sealed, darkened containers. Chlorate residues in tomato and cantaloupe edible flesh homogenates were less than the LC-MS/MS limit of quantitation (60 and 30 ng/g respectively), but were 1319 ± 247 ng/g in rind + edible flesh of cantaloupe. Perchlorate residues in all fractions of chlorine dioxide-treated tomatoes and cantaloupe were not different (P > 0.05) than perchlorate residues in similar fractions of untreated tomatoes and cantaloupe. Data from this study suggest that chlorine dioxide sanitation of edible vegetables and melons can be conducted without the formation of unwanted residues in edible fractions.


    Directory of Open Access Journals (Sweden)



    Full Text Available Cette étude a été réalisée en vue d’apporter des rép onses convaincantes aux préoccupations des consommateurs de la commune de Soumaa sur la qualité de l'eau de robinet. Pour évaluer l’efficacité du traitement (chloration, un suivi saisonnier durant une période de sept mois de la qualité bactériologique des échantillons d'eau prélevés depuis la source (oued Bouchemla jusqu'au point d'usage, en passant par le stade d'eau traitée (après sa chloration a été effectué. Les résultats obtenus pour les 49 échantillons prélevés ont montré que : - 57,14% des échantillons d'eau prélevés après son traitement présentent un chlore positif, et 42,85% des échantillons sont de bonne qualité bactériologique. -60% des prélèvements effectués auprès des consommateurs sont de bonne qualité bactériologique, parmi eux, 34,28% ont présenté un chlore négatif.

  15. Synthesis and Characterization of Highly Intercalated Graphite Bisulfate (United States)

    Salvatore, Marcella; Carotenuto, Gianfranco; De Nicola, Sergio; Camerlingo, Carlo; Ambrogi, Veronica; Carfagna, Cosimo


    Different chemical formulations for the synthesis of highly intercalated graphite bisulfate have been tested. In particular, nitric acid, potassium nitrate, potassium dichromate, potassium permanganate, sodium periodate, sodium chlorate, and hydrogen peroxide have been used in this synthesis scheme as the auxiliary reagent (oxidizing agent). In order to evaluate the presence of delamination, and pre-expansion phenomena, and the achieved intercalation degree in the prepared samples, the obtained graphite intercalation compounds have been characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR), micro-Raman spectroscopy ( μ-RS), and thermal analysis (TGA). Delamination and pre-expansion phenomena were observed only for nitric acid, sodium chlorate, and hydrogen peroxide, while the presence of strong oxidizers (KMnO4, K2Cr2O7) led to stable graphite intercalation compounds. The largest content of intercalated bisulfate is achieved in the intercalated compounds obtained from NaIO4 and NaClO3.

  16. Dissimilatory reduction of perchlorate and other common pollutants by a consortium enriched from tidal flats of the Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    Nirmala Bardiya; Jae-Ho Bae


    Objective: To enrich a facultative anaerobic bacterial consortium from the Yellow Sea and assess its ability to reduce perchlorate and other co-pollutants. Methods: Bacterial consortium collected from the tidal flats of the Yellow Sea was enriched in an anoxic medium containing perchlorate as the electron (e-) acceptor and acetate as the electron (e-) donor. The enriched consortium was then tested for perchlorate reduction under different perchlorate concentrations and in the presence of nitrate by using standard anaerobic techniques. The complete enzymatic reduction of perchlorate to chloride was confirmed by chlorite dismutation. Ability of the consortium to grow with alternate e- acceptors was also tested with acetate as the e- donor. Results: The enriched consortium could rapidly reduce perchlorate up to the initial concentration of 25.65 mmol/L. In the presence of nitrate, perchlorate reduction did not occur immediately and reduction of nitrate started after a lag phase, with concomitant accumulation of nitrite. The perchlorate-enriched consortium could reduce chlorate, oxygen, Cr (VI), and selenate as the alternate e- acceptors but failed to utilize sulfate, thiosulfate, sulfite, and nitrite. Conclusions: The consortium from the tidal flats of the Yellow Sea could reduce perchlorate and co-contaminants such as chlorate, nitrate, Cr (VI), and selenate under heterotrophic conditions with acetate as the e- donor and carbon source. While perchlorate was completely dismutated into innocuous chloride and oxygen, accumulation of nitrite occurred during the reduction of nitrate.

  17. Analysis of P(VdCl-co-AN-co-MMA)-LiClO4-EC triblock copolymer electrolytes

    Indian Academy of Sciences (India)

    D Inbavalli; S Selvasekarapandian; C Sanjeeviraja; R Baskaran; S Nithya; Junichi Kawamura; Yoshitake Masuda


    The lithium ion conducting copolymer electrolytes based on poly(vinylidene chloride-co-acrylonitrileco- methyl methacrylate) P(VdCl-co-AN-co-MMA)-lithium per chlorate (LiClO4) (P(VdCl-co-AN-co-MMA): LiClO4) and poly(vinylidene chloride-co-acrylonitrile-co-methyl methacrylate)P(VdCl-co-AN-co-MMA)-lithium per chlorate (LiClO4)-ethylene carbonate (EC) (P(VdCl-co-AN-co-MMA):LiClO4:EC) of different compositions were prepared by solution-casting technique. Structural and surface morphological characterizations were studied by X-ray diffraction analysis and scanning electron microscopy measurements, respectively. Thermal and conductivity behaviour of copolymer–salt and copolymer–salt–plasticizer complexes were studied by employing differential scanning calorimetry and AC impedance measurements, respectively. The highest bulk conductivity was found to be 1.94 × 10-4 S cm-1 at 303 K for the plasticized sample. The dielectric behaviour and relaxation parameters of the samples have been presented and discussed.

  18. The Investigation of Magnesium Perchlorate/Iron Phase-mineral Mixtures as a Possible Source of Oxygen and Chlorine Detected by the Sample Analysis at Mars (SAM) Instrument in Gale Crater, Mars (United States)

    Sutter, B.; Heil, E.; Archer, P. D.; Ming, D. W.; Eigenbrode, J. L.; Franz, H. B.; Glavin, D. P.; McAdam, A. C.; Mahaffy, P. R.; Niles, P. B.; Stern, J. C.; Navarro-Gonzalez, R.; McKay, C. P.


    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover detect-ed O2 and HCl gas releases from the Rocknest (RN) eolian bedform and the John Klein (JK) and Cumber-land (CB) drill hole materials in Gale Crater (Fig. 1) [1,2]. Chlorinated hydrocarbons have also been detect-ed by the SAM quadrupole mass spectrometer (QMS) and gas chromatography/mass spectrometer (GCMS) [1,2,3,4]. These detections along with the detection of perchlorate (ClO4(-)) by the Mars Phoenix Lander's Wet Chemistry Laboratory (WCL) [5] suggesting perchlo-rate is a possible candidate for evolved O2 and chlorine species. Laboratory thermal analysis of individual per-chlorates has yet to provide an unequivocal tempera-ture match to the SAM O2 and HCl release data [1,2]. Catalytic reactions of Fe phases in the Gale Crater ma-terial with perchlorates can potentially reduce the de-composition temperatures of these otherwise pure per-chlorate/chlorate phases [e.g., 6,7]. Iron mineralogy found in the Rocknest materials when mixed with Ca-perchlorate was found to cause O2 release temperatures to be closer match to the SAM O2 release data and enhance HCl gas releases. Exact matches to the SAM data has unfortnunately not been achieved with Ca-perchlorate-Fe-phase mixtures [8]. The effects of Fe-phases on magnesium perchlorate thermal decomposi-tion release of O2 and HCl have not been evaluated and may provide improved matches to the SAM O2 and HCl release data. This work will evaluate the thermal decomposition of magnesium perchlorate mixed with fayalite/magnetite phase and a Mauna Kea palagonite (HWMK 919). The objectives are to 1) summarize O2 and HCl releases from the Gale Crater materials, and 2) evaluate the O2 and HCl releases from the Mg-perchlorate + Fe phase mixtures to determine if Mg-perchlorate mixed with Fe-phases can explain the Gale Crater O2 and HCl releases.

  19. Linking methane oxidation with perchlorate reduction: a microbial base for possible Martian life (United States)

    Miller, L. G.; Carlstrom, C.; Baesman, S. M.; Coates, J. D.; Oremland, R. S.


    Recent observations of methane (CH4) and perchlorate (ClO4-) within the atmosphere and surface of Mars, respectively, provide impetus for establishing a metabolic linkage between these compounds whereby CH4 acts as an electron donor and perchlorate acts as an electron acceptor. Direct linkage through anaerobic oxidation of methane (AOM) has not been observed. However, indirect syntrophic oxygenase-dependent oxidation of CH4 with an aerobic methane oxidizer is feasible. The pathway for anaerobic dissimilatory perchlorate reduction includes 3 steps. The first 2 are sequential reductions of (1) perchlorate to chlorate and (2) chlorate to chlorite, mediated by perchlorate reductase. The third step is disproportionation of chlorite to chloride and molecular oxygen, mediated by chlorite dismutase. Utilization of thusly derived oxygen by hydrocarbon-degrading organisms in anoxic environments was first demonstrated by Coates et. al. (1998)1, however the link to aerobic methane oxidation was not examined at that time. Here, we systematically explore the potential for several species of aerobic methanotrophs to couple with chlorite during dissimilatory perchlorate reduction. In one experiment, 0.5 kPa CH4 was completely removed in one day from the headspace of combined cell suspensions of Dechloromonas agitata strain CKB and Methylococcus capsulatus in the presence of 5 mM chlorite. Oxidation of labeled 14CH4 to 14CO2 under similar conditions was later confirmed. Another experiment demonstrated complete removal of 0.2 kPa CH4 over several days by Methylobacter albus strain BG8 with strain CKB in the presence of 5 mM chlorite. Finally, we observed complete removal of 0.2 kPa CH4 in bottles containing natural soil (enriched in methanotrophs by CH4 additions over several weeks) and strain CKB and in the presence of 10 mM chlorite. This soil, collected from a pristine lake shoreline, demonstrated endogenous methane, perchlorate, chlorate and chlorite uptake. Other soil and

  20. Enhanced chlorine dioxide decay in the presence of metal oxides: Relevance to drinking water distribution systems

    KAUST Repository

    Liu, Chao


    Chlorine dioxide (ClO2) decay in the presence of typical metal oxides occurring in distribution systems was investigated. Metal oxides generally enhanced ClO2 decay in a second-order process via three pathways: (1) catalytic disproportionation with equimolar formation of chlorite and chlorate, (2) reaction to chlorite and oxygen, and (3) oxidation of a metal in a reduced form (e.g., cuprous oxide) to a higher oxidation state. Cupric oxide (CuO) and nickel oxide (NiO) showed significantly stronger abilities than goethite (α-FeOOH) to catalyze the ClO2 disproportionation (pathway 1), which predominated at higher initial ClO2 concentrations (56-81 μM). At lower initial ClO2 concentrations (13-31 μM), pathway 2 also contributed. The CuO-enhanced ClO2 decay is a base-assisted reaction with a third-order rate constant of 1.5 × 10 6 M-2 s-1 in the presence of 0.1 g L -1 CuO at 21 ± 1 C, which is 4-5 orders of magnitude higher than in the absence of CuO. The presence of natural organic matter (NOM) significantly enhanced the formation of chlorite and decreased the ClO 2 disproportionation in the CuO-ClO2 system, probably because of a higher reactivity of CuO-activated ClO2 with NOM. Furthermore, a kinetic model was developed to simulate CuO-enhanced ClO 2 decay at various pH values. Model simulations that agree well with the experimental data include a pre-equilibrium step with the rapid formation of a complex, namely, CuO-activated Cl2O4. The reaction of this complex with OH- is the rate-limiting and pH-dependent step for the overall reaction, producing chlorite and an intermediate that further forms chlorate and oxygen in parallel. These novel findings suggest that the possible ClO2 loss and the formation of chlorite/chlorate should be carefully considered in drinking water distribution systems containing copper pipes. © 2013 American Chemical Society.

  1. Structural and electrochemical properties of PEMA with the influence of MWCNT / TiO2 filler (United States)

    Pradeepa, P.; Raj, S. Edwin; Kalaiselvimary, J.; Sowmya, G.; Selvakumar, K.; Prabhu, M. Ramesh


    An attempt has been made to prepare a hybrid Nano composite polymer electrolytes (NCPES) based on Poly(ethyl methacrylate) (PEMA) doped with multiwalled carbon nanotubes (MWCNT) and Titanium oxide (TiO2) as additives, Lithium per chlorate (LiClO4) as ionic salt and Propylene Carbonate as plasticizer (PC) by using solvent casting technique. X-ray diffraction analysis (XRD) confirms the miscibility and amorphous nature of the prepared electrolytes. It has been found from the a.c impedance analysis that the inorganic filler reduces the bulk resistance of the electrolytes and thus ionic conductivity enhanced. A high dielectric loss value is observed for the case of doped MWCNT-PEMA in comparison with pure PEMA and doped TiO2 -PEMA membranes. Based on the study of relaxation spectra, it is found that the relaxation time decreases with increase in temperature.

  2. Biochemical and genetical characterization of nitrate reductase deficient mutants of Petunia. (United States)

    Steffen, A; Schieder, O


    Four NR(-) lines were selected by their resistance to 100 mM chlorate from X-ray irradiated protoplasts of haploid Petunia hybrida var. Mitchell. The four cell lines were characterized by the presence of xanthine dehydrogenase activity and by complementation tests via protoplast fusion. One mutant (line 1) was classified as defective in the NR apoprotein (tentatively, nia-type) and the other three (lines 2, 3, 4) in the molybdenum cofactor (tentatively, cnx-type). Some NR activity (15 %) could be restored by adding unphysiologically high concentrations of molybdate to the culture medium in two of the cnx-lines (lines 3 and 4). The third cnx-line (line 2) had no NR activity. A complementation analysis via protoplast fusion confirmed that the mutants comprised 3 non-allelic groups. From these results it can be concluded that these NR(-) mutants are recessive and that two of the cnx-mutants (lines 3, 4) are allelic.


    Institute of Scientific and Technical Information of China (English)

    郑建华; 韩舞鹰


    The preparation method of ClO2, its some present products and application are introduced in this paper. Its preparation methods mainly include chemical and electrolysis methods, and their raw materials are mainly sodium chlorate, sodium chlorite and table salt. The present chloride dioxide products are mainly the stable ClO2 aqueous solution and solid chloride dioxide; the solid chloride dioxide has adsorbing type, gelatifying type and mono-packing type etc. due to different preparation technique. They are extensively applied to the aspects of disinfection, sterilization, algue removal, pulp-bleaching, air purification, food antisepsis and retaining freshness etc. of drinking water, industrial wastewater, hospital sewage, industrial cycle cooling water, fowl slaughter, indoor hygiene, beer production and aquiculture etc.%本文详细地介绍了二氧化氯的制备方法和现有的几种二氧化氯制品及其应用。

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

    Institute of Scientific and Technical Information of China (English)


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

  5. Some Observations on the Ignition of Composite Solid Propellants

    Directory of Open Access Journals (Sweden)

    K. Kishore


    Full Text Available Heat-up times derived from studies on the ignition characteristics of a few model composite solid propellants, containing polystyrene, carboxy-terminated polybutadiene, plasticised polyvinyl chloride and polyphenol formaldehyde as binders, show that they are directly proportional to the mass of the sample and inversely proportional to the heat flux. Propellant weight-loss prior to ignition and high pressure ignition temperature data on the propellants, ammonium per chlorate, and binders show that the ignition is governed by the gasification of the binder pyrolysis products. The activation energy for the gasification of the pyrolysed polymer products corresponds to their ignition behaviour suggesting that propellant ignition is controlled by the binder.

  6. Determination of ribavirin by flow injection chemiluminescence

    Institute of Scientific and Technical Information of China (English)

    Juqing Jin; Yuhai Tang; Langchong He; Hong Yao; Yuanyuan Sun


    Objective: To establish a rapid and precise continuous flow-injection chemiluminescence (CL) method to determine ribavirin. Methods: The ribavirin could restrain strongly CL reaction of luminol in sodium hydroxide (NaOH) solution with potassium chlorate(KClO3). The different experimental parameters affecting the CL intensity were studied carefully. Results:Under optimum conditions(The concentrations of luminol,KClO3, and NaOH were at 0.1 mmol/L,0.5 μmol/L,and 0.2 mol/L, respectively), the linear range of the working curves was 0.01-7.00 μg/ml with a detection limit of 0.004 μg/ml. Conclusion: The method is simple, rapid and sensitive, and successfully applied to the determination of ribavirin in pharmaceutical preparations and biological fluids.

  7. Anionic markers for the forensic identification of Chemical Ignition Molotov Cocktail composition. (United States)

    Martín-Alberca, C; Ferrando, J L; García-Ruiz, C


    An improved version of the famous Molotov cocktail is the Chemical Ignition Molotov Cocktail (CIMC). This incendiary device contains chemical reagents that enable its self-ignition. The analysis of anions from CIMC residues by capillary electrophoresis (CE) allows the identification of the reagents used to produce the device, and provides forensic analysts with valuable information. Although, sulfate, chlorate, chloride, and perchlorate anions have been recently proposed in the literature as target anions to determine the CIMC composition, the identification of some of them could be controversial due to their presence in the environment. Therefore, the purpose of this study was to identify highly reliable anions capable of indicating the components used to prepare these self-initiated devices. The relationship among the detected anions in CIMC residues and the reagents employed in their elaboration is discussed. Some anions have been proposed as anionic markers of CIMC as incendiary devices. Additionally, the viability of different CIMC compositions was studied.

  8. Survey of electrochemical production of inorganic compounds. Final report

    Energy Technology Data Exchange (ETDEWEB)


    The electrochemical generation of inorganic compounds, excluding chlorine/caustic, has been critically reviewed. About 60 x 10/sup 12/ Btu/y fossil fuel equivalent will be used in the year 2000 for the electrosynthesis of inorganic compounds. Significant energy savings in chlorate production can result from the development of suitable electrocatalysts for lowering the cathodic overpotential. Perchlorates, electrolytic hypochlorite, electrolytic manganese dioxide, fluorine and other miscellaneous compounds use relatively small amounts of electrical energy. Implementation of caustic scrubber technology for stack gas cleanup would result in appreciable amounts of sodium sulfate which could be electrolyzed to regenerate caustic. Hydrogen peroxide, now produced by the alkyl anthraquinone process, could be made electrolytically by a new process coupling anodic oxidation of sulfate with cathodic reduction of oxygen in alkaline solution. Ozone is currently manufactured using energy-inefficient silent discharge equipment. A novel energy-efficient approach which uses an oxygen-enhanced anodic reaction is examined.

  9. Mass transfer in the absorption of SO2 and NOx using aqueous euchlorine scrubbing solution

    Institute of Scientific and Technical Information of China (English)

    DESHWAL Bal-Raj; LEE Hyung-Keun


    Attempts have been made to generate euchlorine gas by chlorate-chloride process and to utilize it further to clean up SO2 and NOx from the flue gas in a lab scale bubbling reactor.Preliminary experiments were carried out to determine the gas and liquid phase mass transfer coefficients and their correlation equations have been established.Simultaneous removal of SO2 and NOx from the simulated flue gas using aqueous euchlorine scrubbing solution has been investigated.Euchlorine oxidized NO into NO2 completely and the later subsequently absorbed into the scrubbing solution in the form of nitrate.SO2 removal efficiency of around 100% and NOx removal efficiency of around 72 % were achieved under optimized conditions.Mass balance has been confirmed by analyzing the sulfate, nitrate, euchlorine and chloride ion using ion chromatograph/auto-titrator and comparing it with their corresponding calculated values.

  10. Synthesis by plasma and characterization of semiconductor compounds derived of polyacetylene; Sintesis por plasma y caracterizacion de compuestos semiconductores derivados del poliacetileno

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, M.; Cruz, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Timoshina, T. [ESIQIE-IPN, 07738 Mexico D.F. (Mexico); Olayo, R. [UAM-I, 09340 Mexico D.F. (Mexico)


    In this work it is made a study of the structure and electric properties of chlorate polyethylene (PE-CI) with double and simple bonds obtained by continuous plasma with resistive coupling to 13.5 MHz. The synthesis conditions are power between 10 and 14 W and pressure of (6-7) x 10{sup -2} Torr. The synthesized PE-Cl in that way is soluble in acetone what indicates that probably is formed of short chains and not it shows the generalized inter crossing that is presented in some syntheses by plasma and that it can degrade the electric properties of these polymers. The IR and XPS analysis show the vibration of the C-C, C=C and C-CI bonds. The morphology of the polymer after being dissolved shows a compact and flat configuration. The electric conductivity has an approximately lineal behavior in an interval of 35 to 90% of relative humidity. (Author)

  11. The XPS study of physical and chemical forms of neptunium group on the surface of minerals

    Directory of Open Access Journals (Sweden)

    Teterin Anton Yu.


    Full Text Available The sorption behavior and the physical and chemical forms of neptunium on the surface of minerals of the two chlorate samples, biotite and kaolin, with different contents of Fe(II was studied. The liquid-liquid extraction and the X-ray photoelectron spectroscopy were employed to identify the valence forms of neptunium. On the basis of the obtained data the quantitative elemental composition of the surface of the studied minerals, as well as the ionic composition of the formed neptunium complexes was determined. It was shown that the Np(IV and Np(VI containing compounds did not form, while the complexes Np(VO+ -hydroxyl did form on the surface. The oxygen ions bonded with iron and oxygen belonging to water and/or of carboxyl were suggested to be present in the equatorial plane of the neptunyl group NpO+.

  12. Progress of Chlorine Dioxide Preparation Method%二氧化氯制备方法研究进展

    Institute of Scientific and Technical Information of China (English)

    吴建春; 杨佳财


    二氧化氯是一种具有高氧化性和强消毒性的化合物,本论文介绍了二氧化氯制备的化学法、电解法以及电化学法,并对几种工艺方法的优缺点进行了分析和比较,适合工业化生产的工艺主要是化学法中的氯酸钠法和亚氯酸钠法。%Chlorine dioxide is a high oxidation resistance and strong disinfection compound.This paper introduces the chemical preparation method of dioxide chlorine,electrolysis method and electrochemical method.The advantages and disadvantages of several processing methods were discussed and compared.The process suitable for industrial production is mainly sodium chlorate and sodium chlorite method.

  13. An ion-exchange method for selective separation of palladium, platinum and rhodium from solutions obtained by leaching automotive catalytic converters. (United States)

    Gaita, R; Al-Bazi, S J


    An ion-exchange method has been developed for the separation of palladium, platinum and rhodium from a solution that is highly acidic and contains a considerable amount of lead, aluminum, iron and cerium, obtained by leaching a used honeycomb type automotive catalytic converter. A column of Amberlite IRA-93 anion-exchange resin was found appropriate to recover platinum metals from the pregnant solution. Selective stripping of these metals from the resin was achieved by eluting rhodium first with 6.0M hydrochloric acid, then palladium with a 1% ammonia solution at ambient temperature, and platinum with 5% of the reagent at elevated temperatures. Optimum conditions for leaching these metals from the catalyst were 5.0M hydrochloric acid and 0.4M sodium chlorate at 70 degrees C. This method can be applied to both analytical as well as large scale operations. It is simple, economical, and relatively safe for human exposure and the environment.

  14. Selective chlorine dioxide determination using gas-diffusion flow injection analysis with chemiluminescent detection

    Energy Technology Data Exchange (ETDEWEB)

    Hollowell, D.A.; Gord, J.R.; Gordon, G.; Pacey, G.E.


    An automated chemiluminescent technique has been developed utilizing the advantages of gas-diffusion flow injection analysis. A gas-diffusion membrane separates the donor (sampling) stream from the acceptor (detecting) stream and removes ionic interferences. A novel chemiluminescence flow-through detector cell is used to measure the concentration of chlorine dioxide as a function of the intensity of the chemiluminescence produced from its reaction with luminol. The chemiluminescent reagent merges with the analyte directly in front of the photomultiplier tube in order to maximize the sensitivity of the system. The detection limit for chlorine dioxide is approximately 5 ppb. The method is over 1500 times more selective for chlorine dioxide than for chlorine on a mole basis. This method eliminates interference from iron and manganese compounds, as well as other oxychlorinated compounds such as chlorite ion and chlorate ion.


    Directory of Open Access Journals (Sweden)

    M. Sarwar Jahan


    Full Text Available Bleaching of soda-anthraquinone jute pulp by chlorine dioxide (ClO2 was studied to reach a target brightness of above 88% for the purpose of using less bleaching chemicals. The performance of either chlorine dioxide or peroxide in the final bleaching to boost brightness was also studied. The experimental results revealed that the final brightness depended on ClO2 charge in the Do and D1 stages. The brightness reversion was lower when the final stage brightening was done by peroxide. The use of Mg(OH2 in the D1 and D2 stages improved the final brightness due to the formation of less chlorate and chlorite during the Mg(OH2- based ClO2 brightening stages. The strength properties of pulp bleached by peroxide in the final stage was slightly better than that from ClO2 as the final ClO2 bleaching stage.

  16. In Situ Detection of Chlorine Dioxide (C1O2) in the Radiolysis of Perchlorates and Implications for the Stability of Organics on Mars (United States)

    Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I.


    Magnesium perchlorate hexahydrate (Mg(ClO4)2 · 6H2O) samples were exposed to energetic electrons to investigate the products of the decomposition of perchlorates in the Martian soil and to infer their role in the degradation of organics on Mars. The samples were monitored online and in situ via infrared spectroscopy as well as electron impact (EI-QMS) and reflectron time-of-flight mass spectrometry coupled with single photon ionization (PI-ReTOF-MS). Our study reveals that besides chlorates ({{{ClO}}3}-) and molecular oxygen (O2), the chlorine dioxide radical (ClO2) was observed online and in situ for the first time as a radiolysis product of solid perchlorates. Chlorine dioxide, which is used on Earth as a strong oxidizing agent in water disinfection and bleaching, represents a proficient oxidizer—potentially more powerful than molecular oxygen—to explain the lack of abundant organics in the Martian soil.

  17. Kinetics and mechanism of the oxidation of pentathionate ion by chlorine dioxide in a slightly acidic medium. (United States)

    Xu, Li; Csekő, György; Petz, Andrea; Horváth, Attila K


    The chlorine dioxide-pentathionate reaction has been studied at a slightly acidic medium by conventional UV-vis spectroscopy monitoring the absorbance at 430 nm. We have shown that pentathionate was oxidized to sulfate, but chlorate is also a marginal product of the reaction besides the chloride ion. The stoichiometry of the reaction can be established as a linear combination of two limiting stoichiometries under our experimental conditions. Kinetics of the reaction was found to be also complex because initial rate studies revealed that formal kinetic orders of both the hydrogen ion and chlorine dioxide is far from unity. Moreover, log-log plot of the initial rate against pentathionate concentration indicated a nonconstant formal kinetic order. We also observed a significant catalytic effect of chloride ion. Based on our observations and simultaneous evaluation of the kinetic curves, an 11-step kinetic model is obtained with 6 fitted rate coefficients. A relatively simple rate equation has also been derived and discussed.

  18. Detection of DNA Hypomethylation Mediated Floral Induction in Longan and Spinach Using the HAT-RAPD Technique

    Directory of Open Access Journals (Sweden)

    S. Anuntalabhochai


    Full Text Available In this study, the HAT-RAPD technique was used to detect DNA methylation in the four plant species, rice (Oryza sativa, petunia (Petunia hybrida, spinach (Spinacea oleracea L. and longan (Dimocarpus longan Lour., which were treated using 5-azacytidine, potassium chlorate (KClO3 and a low temperature induction. Rice and petunia were chosen to be induced because in these species it is known that 5-azacytidine is able to induce hypomethylation in their genomes leading to morphological changes, in particular floral induction, in the developing plants. Using the HAT-RAPD technique, DNA methylation was detected using the restriction enzymes HpaII and MspI in rice and petunia (as expected and in spinach, but was found to be absent in longan, which suggests that floral induction in longan is undetectable in longan.

  19. Preparation and characterization of CoFe2O4/TiO2 magnetic composite films

    Institute of Scientific and Technical Information of China (English)


    CoFe2O4/TiO2 magnetic composite films were prepared using the sol-gel method with tetrabutyltitanate and metallic chlorates as starting materials. The effects of heat treatment temperatures on micro- structures and on magnetic properties were studied. The microstructure and properties of the samples at different heat treatment temperatures were characterized by X-ray diffraction, Raman spectrum, scanning electron microscopy, polarized microscopy and vibrating sample magnetometry. The results show that crystals of different substances grow up independently. Cobalt ferrite is evenly embedded into the titanium dioxide matrix in the prepared composite films. The magnetism of the composite films is enhanced with an increase of the heat temperature.

  20. Ion chromatography in the manufacture of multilayer circuit boards (United States)

    Smith, Robert E.


    Ion chromatography (IC) has proven useful in analyzing chemical solutions used in the manufacture of multilayer circuit boards. The manufacturing process is described briefly and previously published IC methods are reviewed. Then, methods are described for determining chlorate and chlorite in a brown oxide solution; salicylic acid in an epoxy cure agent; formate, sulfate, and tartrate in an electroless copper bath; anionic detergents in a tin-lead brightener and in a cleaning solution; and aqueous photoresist and nonionic brightener in a tin-lead bath. Anion exchange, reverse phase HPLC on a poly(styrene/divinylbenzene), PS/DVB, column and 2-D liquid chromatography also are described. Chemically suppressed conductivity and photometric detection are used.

  1. Analysis of oxyhalide disinfection by-products and other anions of interest in drinking water by ion chromatography. (United States)

    Hautman, D P; Bolyard, M


    The US Environmental Protection Agency is developing regulations for various drinking water disinfection by-products (DBPs). This effort involves developing analytical methods for the DBPs formed as a result of different disinfection treatments and collecting occurrence data for these species. Ion chromatography is one method being used to analyze drinking water samples for the following inorganic DBPs: chlorite, chlorate and bromate. These anions, however, are difficult to separate from common interfering anions of chloride, carbonate and nitrate. A method is therefore presented by which tetraborate/boric acid is used to separate these anions. Method detection limits of the order of 10 micrograms/l, using conductivity and UV detection were obtained. Stability studies of chlorite showing the effectiveness of ethylenediamine as a preservative and summary data for an occurrence of nitrite, nitrate and the DBP precursor bromide are presented.

  2. Determination of silver, bismuth, cadmium, copper, lead, and zinc in geologic materials by atomic absorption spectrometry with tricaprylylmethylammonium chloride (United States)

    Viets, J.G.


    Interferences commonly encountered in the determination of silver, bismuth, cadmium, copper, lead, and zinc at crustal abundance levels are effectively eliminated using a rapid, sensitive, organic extraction technique. A potassium chlorate-hydrochloric acid digestion solubilizes the metals not tightly bound in the silicate lattice of rocks, soils, and stream sediments. The six metals are selectively extracted into a 10% Aliquat 336-MIBK organic phase in the presence of ascorbic acid and potassium iodide. Metals in the organic extract are determined by flame atomic absorption spectrometry to the 0.02-ppm level for silver, cadmium, copper, and zinc and to the 0.2-ppm level for bismuth and lead with a maximum relative standard deviation of 18.8% for known reference samples. An additional hydrofluoric acid digestion may be used to determine metals substituted in the silicate lattice.

  3. Synthesis of Graphene Oxide by Oxidation of Graphite with Ferrate(VI) Compounds: Myth or Reality? (United States)

    Sofer, Zdeněk; Luxa, Jan; Jankovský, Ondřej; Sedmidubský, David; Bystroň, Tomáš; Pumera, Martin


    It is well established that graphene oxide can be prepared by the oxidation of graphite using permanganate or chlorate in an acidic environment. Recently, however, the synthesis of graphene oxide using potassium ferrate(VI) ions has been reported. Herein, we critically replicate and evaluate this new ferrate(VI) oxidation method. In addition, we test the use of potassium ferrate(VI) for the synthesis of graphene oxide under various experimental routes. The synthesized materials are analyzed by a number of analytical methods in order to confirm or disprove the possibility of synthesizing graphene oxide by the ferrate(VI) oxidation route. Our results confirm the unsuitability of using ferrate(VI) for the oxidation of graphite on graphene oxide because of its high instability in an acidic environment and low oxidation power in neutral and alkaline environments.

  4. Drinking Water Disinfection by In-line Electrolysis: Product and Inorganic By-Product Formation (United States)

    Bergmann, M. E. Henry

    This section covers peculiarities of so-called in-line electrolysis when drinking water is electrolysed to produce disinfection species killing microorganisms. Mainly mixed oxide electrodes (MIO) based on IrO2 and/or RuO2 coatings and boron-doped diamond electrodes were used in the studies. Artificial and real drinking water systems were electrolysed in continuous and discontinuous operating mode, varying water composition, current density and electrode materials. Results show, besides the ability of producing active chlorine, risks of inorganic disinfection by-products (DBPs) such as chlorate, perchlorate, nitrite, ammonium, chloramines, hydrogen peroxide and others. DBPs are responsible for analysis errors using DPD method for active chlorine measurements. Geometry may influence by-product yield. As a conclusion, the necessity of developing test routines for practical cell applications must be underlined.

  5. Alternative Electrode Materials and Ceramic Filter Minimize Disinfection Byproducts in Point-of-Use Electrochemical Water Treatment (United States)

    Yoon, Yeojoon; Jung, Youmi; Kwon, Minhwan; Cho, Eunha; Kang, Joon-Wun


    Abstract Effects of various electrodes and prefiltration to minimize disinfection byproducts (DBPs) in electrochemical water disinfection was evaluated. The target microorganism, Escherichia coli O157:H7, was effectively inactivated even applying a solar-charged storage battery for the electrolysis process. Extent of microbial inactivation decreased with lower water temperature and higher pH in the free chlorine disinfection system. The RuO2/Ti electrode was most efficient because it produced the lowest concentration of chlorate and the highest generation of free chlorine. Prefiltration using a ceramic filter inhibited formation of halogenated DBPs because it removed precursors of DBPs. For safe point-of-use water treatment, the use of a hybrid prefiltration stage with the electrolysis system is strongly recommended to reduce risks from DBPs. The system is particularly suited to use in developing regions. PMID:24381482

  6. Alternative Electrode Materials and Ceramic Filter Minimize Disinfection Byproducts in Point-of-Use Electrochemical Water Treatment. (United States)

    Yoon, Yeojoon; Jung, Youmi; Kwon, Minhwan; Cho, Eunha; Kang, Joon-Wun


    Effects of various electrodes and prefiltration to minimize disinfection byproducts (DBPs) in electrochemical water disinfection was evaluated. The target microorganism, Escherichia coli O157:H7, was effectively inactivated even applying a solar-charged storage battery for the electrolysis process. Extent of microbial inactivation decreased with lower water temperature and higher pH in the free chlorine disinfection system. The RuO2/Ti electrode was most efficient because it produced the lowest concentration of chlorate and the highest generation of free chlorine. Prefiltration using a ceramic filter inhibited formation of halogenated DBPs because it removed precursors of DBPs. For safe point-of-use water treatment, the use of a hybrid prefiltration stage with the electrolysis system is strongly recommended to reduce risks from DBPs. The system is particularly suited to use in developing regions.

  7. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Nurhadini,, E-mail:; Arcana, I Made, E-mail: [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institiut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)


    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  8. Metabolism and pharmacokinetics of alternate drinking water disinfectants. (United States)

    Abdel-Rahman, M S; Couri, D; Bull, R J


    The chlorination of surface waters is known to elevate trihalomethanes; consequently, chlorine dioxide (ClO2) is being considered as an alternative disinfectant. The primary products resulting from ClO2 disinfection of waters are chlorites (ClO2-) and chlorates (ClO3-). Studies in rats revealed that ClO2 is converted to chloride (Cl-), ClO2- and ClO3-. ClO2- and ClO3- are excreted as Cl-, ClO2- and Cl-, ClO2-, ClO3-, respectively. Radioactivity was rapidly absorbed from the gastrointestinal tract following the administration of 36ClO2 orally, and the half-life for the elimination of 36Cl from the rat was 44 hr, corresponding to a rate constant of 0.016/hr. After 72 hr, radioactivity was highest in plasma, followed by kidney, lung, and stomach. 36Cl in plasma reached a peak at 2 hr and 1 hr after oral administration of 36ClO2- and 36ClO3-, respectively. 36Cl excretion was greatest 24 hr after the administration of 36ClO3-, but in the case of 36ClO2-, the excretion probably represented saturation of the biotransformation and excretion pathway. A low activity in packed cells compared to plasma was detected in chlorate ingestion, rather than an even distribution in chlorite treatment. Chloroform determinations in rat blood after one year indicated that chloroform was significantly higher than control in the 100 and 1000 mg/l. ClO2 groups. However, no significant values were observed in the 1 or 10 mg/l. ClO2 and ClO2 metabolites groups. ClO2 and its metabolites are eliminated from the body more rapidly than chlorine, and they do not appear to increase trihalomethane concentrations at low dosages.

  9. 草酸钠作为促染剂在活性黄3RS染色中的应用%Using Sodium Oxalate in the Dyeing of Cotton Fabric with Reactive Yellow 3 RS as an Accelerant

    Institute of Scientific and Technical Information of China (English)

    虞波; 周康; 胡文乾; 叶晓燕


    草酸盐作为光催化促进剂,在光化学反应中有着广泛的应用.研究了在活性黄3RS染棉织物过程中,草酸钠作为促染剂以取代无机盐(硫酸钠和氯化钠)的可行性,并将草酸钠与甲酸钠和柠檬酸钠等有机盐的促染效果进行了比较.结果显示草酸钠的促染效果优于甲酸钠、柠檬酸钠和氯化钠,与硫酸钠的促染效果相当.草酸钠作为促染剂,对染色织物的染色牢度和色光均没有影响.草酸钠可以取代无机盐,提高降解染色废水的光化学效果.%Sodium oxalate is used widely in the field of photochemical reaction as an accelerant. The feasibility of using sodium oxalate in the dyeing of cotton fabrics with reactive dyes in place of inorganic salt ( sodium sulfate or sodium chlorate) was studied. Meanwhile, the dyeing of cotton fabrics with reactive dyes using sodium formate and sodium citrate were investigated and the results obtained were compared with that of sodium oxalate. The re-sults show that the effect of sodium oxalate as an accelerant is better than that of sodium formate, sodium citrate and sodium chlorate, and its effect is equal to that of sodium sulfate. Sodium oxalate has no effect on the fastness and shade of the dyed fabric as an exhausting agent. Sodium oxalate could substitute for inorganic salt to enhance photochemical reaction of dyeing wastewater.

  10. Preparation of polyferric chloride sulfate%聚合氯化硫酸铁制备方法

    Institute of Scientific and Technical Information of China (English)



    聚合氯化硫酸铁是一种新型高效无机高分子水处理剂,其制备方法包括氯酸盐氧化法和氯气氧化法,即硫酸亚铁溶液在一定温度和酸度下与氯酸钠或液氯反应,生成一系列不同聚合度的聚铁溶液,温度、酸度和氧化剂都可影响其聚合度,不同产品用于水处理时效果也相差甚远.氯酸盐氧化法制备聚合氯化硫酸铁与氯气氧化法相比在成本和环保方面都占优,该方法代表了聚合氯化硫酸铁的工业生产方法.%Polyferric chloride sulfate (PFCS) is a new - type high - performance inorganic macromolecular water treatment agent.Its main preparation methods include chlorate oxidation method and chlorine oxidation method,namely ferrous sulfate solution react with sodium chlorate or liquid chlorine at a certain temperature and acidity to generate a series of PFCS solution with different polymerization degrees.Temperature,acidity,and oxidants can affect polymerization degree of the products and effect will differ greatly when they were used as water treatment agents.Compared with chlorine oxidation method,the other one is dominant in both terms of cost and environment protection,and it represents the industrial production method for PFCS.

  11. Integrated Data Collection Analysis (IDCA) Program - AN and Bullseye Smokeless Powder

    Energy Technology Data Exchange (ETDEWEB)

    Sandstrom, Mary M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Geoffrey W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pollard, Colin J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Warner, Kirstin F. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States); Sorensen, Daniel N. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States); Remmers, Daniel L. [Naval Surface Warfare Center (NSWC), Indian Head, MD (United States); Phillips, Jason J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelley, Timothy J. [Bureau of Alcohol, Tobacco, and Firearms, Redstone Arsenal, AL (United States); Reyes, Jose A. [Applied Research Associates, Tyndall Air Force Base, FL (United States); Hsu, Peter C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Reynolds, John G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    chlorate, sodium chlorate, sugar, dodecane, PETN, carbon, ammonium nitrate, Gunpowder, Bullseye® smokeless powder.

  12. Soil transport parameters of potassium under a tropical saline soil condition using STANMOD (United States)

    Suzanye da Silva Santos, Rafaelly; Honorio de Miranda, Jarbas; Previatello da Silva, Livia


    Environmental responsibility and concerning about the final destination of solutes in soil, so more studies allow a better understanding about the solutes behaviour in soil. Potassium is a macronutrient that is required in high concentrations, been an extremely important nutrient for all agricultural crops. It plays essential roles in physiological processes vital for plant growth, from protein synthesis to maintenance of plant water balance, and is available to plants dissolved in soil water while exchangeable K is loosely held on the exchange sites on the surface of clay particles. K will tend to be adsorbed onto the surface of negatively charged soil particles. Potassium uptake is vital for plant growth but in saline soils sodium competes with potassium for uptake across the plasma membrane of plant cells. This can result in high Na+:K+ ratios that reduce plant growth and eventually become toxic. This study aimed to obtain soil transport parameters of potassium in saline soil, such as: pore water velocity in soil (v), retardation factor (R), dispersivity (λ) and dispersion coefficient (D), in a disturbed sandy soil with different concentrations of potassium chlorate solution (KCl), which is one of the most common form of potassium fertilizer. The experiment was carried out using soil samples collected in a depth of 0 to 20 cm, applying potassium chlorate solution containing 28.6, 100, 200 and 500 mg L-1 of K. To obtain transport parameters, the data were adjusted with the software STANMOD. At low concentrations, interaction between potassium and soil occur more efficiently. It was observed that only the breakthrough curve prepared with solution of 500 mg L-1 reached the applied concentration, and the solution of 28.6 mg L-1 overestimated the parameters values. The STANMOD proved to be efficient in obtaining potassium transport parameters; KCl solution to be applied should be greater than 500 mg L-1; solutions with low concentrations tend to overestimate

  13. 甘油合成1,3-丙二醇%Synthesis of 1,3-Propanediol from Glycerol

    Institute of Scientific and Technical Information of China (English)

    陈国辉; 孙全


    1,3-Propanediol was synthesized from glycerol by chloration,oxidation, Clemmensen reaction and hydrolysis. The structure of the target compound was determined by method of IR and MS. The molar ratio, temperature and solvent of the reaction were investigated to optimize the reaction conditions. The optimum conditions are: for chloration: 120 ℃; for oxidation: 23 ~ 27 ℃, n ( 1,3-dichloroacetone ): n ( sodium dichromate) = 1.8:1, the amount of reaction solvent: 1.4 g 1,3-dichloro-2-propanol per 1 mL water, and for Clemmensen reaction: n (1,3-dichloropropane): n ( zinc )= 1:1.2, with water as the desirable solvent, and the overall yield of 37. 1%.%以甘油为原料,经过氯代、氧化、克莱门森还原、水解4步反应,最终合成1,3-丙二醇,并用红外光谱仪和质谱仪对目标产物进行结构确定.从反应物摩尔比、反应温度、反应溶剂等优化了反应条件.最优反应条件为:氯代反应:温度120℃;氧化反应:温度23~27℃,,n(1,3-二氯-2-丙醇):n(重铬酸钠)=1.8:1,反应溶剂用量:1 mL水溶解1.4 g 1,3-二氯-2-丙醇;克莱门森还原反应:n(1,3-二氯丙酮):n(锌)=1:1.2,水作反应溶剂最佳,在该条件下,1,3-丙二醇总产率可达37.1%.

  14. Radiation chemical effects in the near-field environment of a radwaste repository: {gamma} radiolysis in 6 molal NaCl solutions; Strahlenchemische Effekte im Endlagernahbereich: {gamma}-Radiolyse in 6 molarer NaCl-Loesung

    Energy Technology Data Exchange (ETDEWEB)

    Kelm, M.; Bohnert, E.


    The radiation emitted from high-level radioactive wastes in a radwaste repository causes radiolysis products to be formed in brines resulting from water intrusion. The products may alter via redox and complexing reactions the mobilisation processes of radionuclides. The major products of {gamma} radiolysis determined in 6 molal NaCl solution as a function of radiation dose are hydrogen, oxygen, and chlorate. Hypochlorite and chlorite were found to have concentrations in the {mu}Mol/kg range. There was no dependence on dose rate. For the experiments under atmospheric pressure, which allowed radiolytic gas to escape from the solution, the G values measured are 0.46 (H{sub 2}), 0.16 (O{sub 2}), and 0.074 (ClO{sub 3}). In pressurized experiments, with radiolytic gas remaining contained in the solution, the radiolytic effect was much smaller. After approx. 100 days, at a dose of about 2 MGy, gas equilibrium concentrations of some mMol/kg were measured. The results can be qualitatively described by a system of parallel running reaction rate equations. As to quantitative analysis, the reaction model needs to be refined. (orig./CB) [Deutsch] Die Strahlung von hochradioaktiven Abfaellen in einem Endlager im Salz hat zur Folge, dass bei einem Wasserzutritt in den entstehenden Laugen Radiolyseprodukte gebildet werden. Die Radiolyseprodukte koennen durch Redox- und Komplexierungsreaktionen die Mobilisierbarkeit von Radionukliden veraendern. Als Hauptprodukte der {gamma}-Radiolyse wurden in 6 molaler NaCl-Loesung Wasserstoff, Sauerstoff und Chlorat in Abhaengigkeit von der Dosis bestimmt. Hypochlorit und Chlorit erreichten nur Konzentrationen im {mu}Mol/kg-Bereich. Eine Dosisleistungsabhaengigkeit war nicht festzustellen. Bei den Experimenten unter Normaldruck, bei denen die Radiolysegase aus der Loesung entweichen konnten, betrugen die G-Werte 0.46 (H{sub 2}), 0,16 (O{sub 2}) und 0,074 (ClO{sub 3}{sup -}). Bei den Experimenten unter Druck wurden die Radiolysegase in Loesung

  15. 尿样消化对尿碘检测结果质量的影响分析

    Institute of Scientific and Technical Information of China (English)



    目的:探讨尿样消化对尿碘检测结果的影响。方法:随机选取20份尿检样品,采用氯酸消化法进行尿碘检测,采用两种不同质量的消化管进行尿样消化,观察两种消化管的消化结果,分析尿样消化对尿碘检测的影响。结果:消化管A尿碘检测质量优于消化管B,消化剩余酸量大于0.4ml或小于0.2ml,可见,消化温度及氯酸量是尿碘检测主要影响因素。结论:尿样消化温度需控制在110℃~115℃范围内,且氯酸量应为0.5ml,避免尿样消化对尿碘检测的影响。%Objective: to investigate the results of urine sample digestion for detecting urine iodine.Methods: randomly selected 20 samples of urine and chloric acid digestion method for urine iodine testing, using two different quality of digestive tube to carry on the urine sample digestion, observation of two kinds of digestive tube digestion as a result, the analysis of the effect of urine sample digestion for detecting urine iodine.Results: the digestive tube A urinary iodine testing quality is better than that of the digestive tube B, digesting residual acid amount is greater than 0.4 ml or less than 0.2 ml, visible, digestion temperature and quantity of chlorate are the main factors that influence the urine iodine testing.Conclusion: the urine sample digestion temperature to control within 110 ℃ ~ 115 ℃, and the amount of chlorate should be 0.5 ml, avoid the influence of the urine sample digestion for detecting urine iodine.

  16. Oxidative discharge printing process of denim fabric with low cost%低成本靛蓝牛仔布氧化拔染印花工艺

    Institute of Scientific and Technical Information of China (English)



      借鉴苯胺黑黑地防染印花工艺中的氯酸钠和黄血盐钾氧化组合,作为靛蓝氧化拔染剂,以柠檬酸为酸性介质,可以实现靛蓝牛仔布的氧化拔染印花,还可以用于靛蓝套染硫化染料或直接染料地色拔染印花等。生产中根据拔染效果和织物强力,可以调整氯酸钠和黄血盐钾用量和酸的用量,比商品靛蓝拔染剂如拔染剂C-100、拔染剂JN等更有优势,印花成本低,制浆采用冷法制备,简便快捷、汽蒸时间短、工艺条件可控、重现性好,能有效控制织物的强力损失。无甲醛使靛蓝拔染印花获得新生。%In view of the combination of sodium chlorate and yellow prussiate of potash used in black-based dye-resist printing process for aniline black as oxidative discharging agent, oxidative discharge printing of denim fabric can be realized through citric acid used as acidic medium. This kind combination can also be applied in the discharge printing based on sulfur dye or direct dye used with indigo. The dosage of sodium chlorate, yellow prussiate of potash and acid can be adjusted according to discharge effect and fabric strength in manufacture. It is superior to commercial discharging agents such as discharging agent C-100 and discharging agent JN due to low cost. The paste is prepared by cold method, which presented advantages as simpleness, rapidness, short steaming time, controlled technological conditions, good reproducibility and effective control the loss of fabric strength. Moreover, the formaldehyde-free process recreates indigo discharge printing.

  17. Identification of inorganic improvised explosive devices by analysis of postblast residues using portable capillary electrophoresis instrumentation and indirect photometric detection with a light-emitting diode. (United States)

    Hutchinson, Joseph P; Evenhuis, Christopher J; Johns, Cameron; Kazarian, Artaches A; Breadmore, Michael C; Macka, Miroslav; Hilder, Emily F; Guijt, Rosanne M; Dicinoski, Greg W; Haddad, Paul R


    A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption onto the capillary wall. Glacial acetic acid (0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris

  18. Direct electrochemical oxidation of ammonia on graphite as a treatment option for stored source-separated urine. (United States)

    Zöllig, Hanspeter; Fritzsche, Cristina; Morgenroth, Eberhard; Udert, Kai M


    Electrolysis can be a viable technology for ammonia removal from source-separated urine. Compared to biological nitrogen removal, electrolysis is more robust and is highly amenable to automation, which makes it especially attractive for on-site reactors. In electrolytic wastewater treatment, ammonia is usually removed by indirect oxidation through active chlorine which is produced in-situ at elevated anode potentials. However, the evolution of chlorine can lead to the formation of chlorate, perchlorate, chlorinated organic by-products and chloramines that are toxic. This study focuses on using direct ammonia oxidation on graphite at low anode potentials in order to overcome the formation of toxic by-products. With the aid of cyclic voltammetry, we demonstrated that graphite is active for direct ammonia oxidation without concomitant chlorine formation if the anode potential is between 1.1 and 1.6 V vs. SHE (standard hydrogen electrode). A comparison of potentiostatic bulk electrolysis experiments in synthetic stored urine with and without chloride confirmed that ammonia was removed exclusively by continuous direct oxidation. Direct oxidation required high pH values (pH > 9) because free ammonia was the actual reactant. In real stored urine (pH = 9.0), an ammonia removal rate of 2.9 ± 0.3 gN·m(-2)·d(-1) was achieved and the specific energy demand was 42 Wh·gN(-1) at an anode potential of 1.31 V vs. SHE. The measurements of chlorate and perchlorate as well as selected chlorinated organic by-products confirmed that no chlorinated by-products were formed in real urine. Electrode corrosion through graphite exfoliation was prevented and the surface was not poisoned by intermediate oxidation products. We conclude that direct ammonia oxidation on graphite electrodes is a treatment option for source-separated urine with three major advantages: The formation of chlorinated by-products is prevented, less energy is consumed than in indirect ammonia oxidation and

  19. Conductive diamond electrochemical oxidation of caffeine-intensified biologically treated urban wastewater. (United States)

    Martín de Vidales, María J; Millán, María; Sáez, Cristina; Pérez, José F; Rodrigo, Manuel A; Cañizares, Pablo


    In this work, the usefulness of Conductive Diamond Electrochemical Oxidation (CDEO) to degrade caffeine in real urban wastewater matrixes was assessed. The oxidation of actual wastewater intensified with caffeine (from 1 to 100 mg L(-1)) was studied, paying particular attention to the influence of the initial load of caffeine and the differences observed during the treatment of caffeine in synthetic wastewater. The results showed that CDEO is a technology that is capable of efficiently degrading this compound even at very low concentrations and that it can even be completely depleted. Profiles of the ionic species of S (SO4(2-)), N (NH4(+), NO3(-)) and Cl (ClO(-), ClO3(-) and ClO4(-)) were monitored and explained for plausible oxidation mechanisms. It was observed that the efficiency achieved is higher in the treatment of real wastewater than in the oxidation of synthetic wastewater because of the contribution of electrogenerated oxidant species such as hypochlorite. The formation of chlorate and perchlorate during electrochemical processes was observed, and a combined strategy to prevent this important drawback was successfully tested based on the application of low current densities with the simultaneous dosing of hydrogen peroxide.

  20. Glycoprotein C of equine herpesvirus 4 plays a role in viral binding to cell surface heparan sulfate. (United States)

    Azab, Walid; Tsujimura, Koji; Maeda, Ken; Kobayashi, Kyousuke; Mohamed, Yassir Mahgoub; Kato, Kentaro; Matsumura, Tomio; Akashi, Hiroomi


    Heparan sulfate moieties of cell surface proteoglycans serve as receptors for several herpesviruses. For herpes simplex virus 1, pseudorabies virus and equine herpesvirus 1, glycoprotein C (gC) homologues have been shown to mediate the binding to cell surface heparan sulfate. However, the role of gC in equine herpesvirus 4 (EHV-4) infection has not yet been analyzed. Using pull-down assay, we first determined that EHV-4 gC as well as gB are heparin-binding glycoproteins. To study the role of gC in EHV-4 infection, we constructed a gC-deletion mutant, WA79DeltagC, where the kanamycin resistant gene was inserted instead of the open reading frame encoding gC. We found that soluble heparin was capable of blocking both wild-type EHV-4 and WA79DeltagC infection of fetal horse kidney. Furthermore, pretreatment of cells with heparinase reduces considerably the ability of both viruses to adsorb to these cells and to form plaques. Similar results were obtained when cellular glycosaminoglycan synthesis was inhibited by chlorate treatment. In addition, we did find that gC protects EHV-4 from complement-mediated neutralization. These results suggest that, like other herpesviruses, EHV-4 gC plays a role in the interaction of the virus with cellular heparan sulfate. Moreover, gC can protect the virus from complement-mediated neutralization.

  1. An environmental survey relating to improvised and emulsion/gel explosives. (United States)

    Walker, C; Cullum, H; Hiley, R


    The detection and identification of traces of inorganic ions and sugars can play a major role in the forensic investigation of an explosives related incident. This survey investigated the background levels of these substances in the general environment. Six sampling locations were selected from around the mainland of the United Kingdom, representing urban and rural sites. Swab and vacuum samples were collected from different locations within each site including motor vehicles, private houses, hotels, the exterior of buildings, road surfaces, and street signs. Sampling was carried out in summer and winter to investigate changes in the levels of the target species due to seasonal factors such as road treatments or weather. The samples were extracted with water and analyzed for a range of inorganic anions, cations, and sugars using ion chromatography. Most of the target anions were found to be common to all locations. Chloride, sulphate, nitrate, and phosphate were found to be the most common and the most abundant. Chlorate was found at a low level in some external samples. Perchlorate and thiocyanate were not detected in any samples. There was a marked increase in the quantity of sodium and chloride detected in samples collected during the winter. Sodium and calcium were detected in most samples. Potassium and magnesium were detected in approximately half of the samples. Ammonium was less common but detected at significant levels in wall samples. Glucose, fructose, and sucrose were detected in the vacuum samples from the interior surfaces of houses, hotels, and cars.

  2. Synthesis,Crystal Structure and Electrochemical Properties of a One-dimensional Chain Coordination Polymer[Cu(phen)(2,4,6-TMBA)2(H2O)]n

    Institute of Scientific and Technical Information of China (English)

    LI Wei; LI Chang-Hong; YANG Ying-Qun; KUANG Yun-Fei


    A one-dimensional chain coordination polymer[Cu(phen)(2,4,6-TMBA)2(H2O)]n has been synthesized by reacting 2,4,6-trimethyl-benzoic acid,1,10-phenanthroline and Cu(Ⅱ)per-chlorate and its structure Was characterized.Crystal data for this complex:tetragonal,space group I41,a=2.0293(3),b=2.0293(3),c=113758(2)nm,a=β=γ=90°,V=5.6657(13)nm3,Dc=1.379g/cm3,Z=8,μ(MoKa)=0.815mm-1,Mr=588.14,F(000)=2456,S=1.047,R=0.0459 and wR=O.1053.The crystal structure shows that two neighboring Cu(Ⅱ)ions are linked together by one bridging-chelating 2,4,6-trimethyl-benzoic group,forming a one-dimensional chain structure.Each Cu(Ⅱ)ion is coordinated with two nitrogen atoms from one 1,10-phenanthroline molecule,three oxygen atoms from three 2,4,6-trimethyl-benzoic acid molecules and one oxygen atom from one water molecule,giving a six-coordinate distorted octahedral coordination geometry.The cyclic voltamrnetry behavior of the complex was also investigated.

  3. Water-miscible cooling lubricants - determination of anorganic anions and carboxylic acids using capillary zone electrophoresis; Wassermischbare Kuehlschmierstoffe - Bestimmung von anorganischen Anionen und Carbonsaeuren mittels der Kapillarzonenelektrophorese

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, B.A. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Dengel, H.S. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Hohaus, E. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Maurer, W. [Fachbereich 8, Analytische Chemie II, Universitaet-GH Siegen (Germany); Riepe, W. [Fachbereich 13, Analytische Chemie, Universitaet-GH Paderborn (Germany)


    A procedure is presented which allows the quantitative determination for most of the essentiell inorganic anions besides several carbonic acids (oxalic-, citric-, malonic-, tartaric-, formic-, succinic- and adipinic acid) in concentrates and industrial application emulsions of watermiscible cooling lubricants either free of mineral oil or oleiferous. The method used is based on capillary zones electrophoresis (CZE) using indirect UV-detection. The quantification of these substances regarding a qualiy surveillance of lubricants for manufacturers and a control of possible toxicological infleunces in working places is easily performed in spite of the complex matrix of the lubricants. Only a simple dilution is necessary. Analytical chemcial parameters such as accuracy, precision and recovery rate for concentrates and emulsions in industrial use for 1995/96 reveal sufficient universal application of the presented method for general purpose analyzing cooling lubricants. (orig.) [Deutsch] Es wird ein Verfahren vorgestellt, mit dem in Konzentraten und Emulsionen von wassermischbaren mineraloelfreien und mineraloelhaltigen Kuehlschmierstoffen (KSS) neben den wesentlichen anorganischen Anionen (Thiosulfat, Bromid, Chlorid, Sulfat, Nitrit, Nitrat, Perchlorat, Chlorat, Phosphonat, Fluorid, Phosphat) Carbonsaeuren (Oxal-, Citronen-, Malon-, Wein-, Ameisen-, Bernstein- und Adipinsaeure) mit Hilfe der Kapillarzonenelektrophorese (CZE) und indirekter UV-Detektion quantitativ bestimmt werden koennen. Die Quantifizierung dieser Substanzen im Rahmen von Qualitaetssicherungs- und Arbeitsschutzmassnahmen in KSS ist trotz der komplexen Matrix der KSS ohne eine aufwendige Probenvorbereitung moeglich. Ein einfacher Verduennungsschritt der Proben genuegt. Die analytischen Verfahrenskenngroessen Richtigkeit, Praezision, Wiederfindung sowie die Untersuchungsergebnisse fuer KSS-Konzentrate einiger Hersteller aus den Produktionsjahren 1995/96 werden vorgestellt. (orig.)

  4. A study of the effects of solid phase reactions on the thermal degradation and ballistic properties of solid propellants (United States)

    Schmidt, W. G.


    The thermal stability of perchlorate composite propellants was studied at 135 and 170 C. The experimental efforts were concentrated on determining the importance of heterogeneous oxidizer-fuel reactions in the thermal degradation process. The experimental approach used to elucidate the mechanisms by which the oxidizer fuel composites thermally degrade was divided into two parts: (1) keeping the fuel constant and varying the nature of the oxidizers, and (2) holding the oxidizer constant and varying the fuel components. The fuel component primarily utilized in the first phase was polyethylene. Oxidizers included KClO4, KClO3, NH4ClO4 and NH4ClO4 doped with materials such as chlorate, phosphate and arsenate. In the second phase the oxidizer used was primarily NH4ClO4 while the fuels included saturated and unsaturated polybutadiene prepolymers and a series of bonding agents. Techniques employed in the current study include thermogravimetric measurements, differential thermal analysis, infrared, mass spectrometry, electron microscopy, and appropriate wet chemical analysis.

  5. Can enantiomorphic crystals like quartz play a role in the origin of homochirality on earth? (United States)

    Klabunovskii, E I


    This communication reviews the possible actions of enantiomorphic crystals on the surface of Earth as sources of homochirality of organic compounds. The discovery of asymmetric adsorption and asymmetric catalysis involving optically active quartz crystals has led some authors to conclude that this source of asymmetry played an important role as a source of homochirality in nature, a concept that later proved erroneous. Moreover, data regarding the preponderance in nature of l-quartz crystals have been used to confirm calculations of the parity violation energy difference (PVED) for l-quartz and, hence, to explain the prevalence of L-amino acids and D-sugars in living matter. As discussed here, quartz and other enantiomorphs such as sodium chlorate can produce chiral intermediates active in autocatalytical processes. Our most recent compilation of the literature, however, reveals that the distribution of d- and l-quartz crystals at the surface of the Earth when all possible locations are included is quite random. Although quartz can serve as an effective asymmetric inductor in autocatalytic processes, it cannot be the source of homochirality of living matter because of the random occurrence of the two types of enantiomorphs. The calculations of PVED values for quartz therefore lack a sound physical basis.

  6. Electrolytic and electro-irradiated processes with diamond anodes for the oxidation of persistent pollutants and disinfection of urban treated wastewater. (United States)

    Cotillas, Salvador; de Vidales, María J Martín; Llanos, Javier; Sáez, Cristina; Cañizares, Pablo; Rodrigo, Manuel A


    This paper analyzes the advantages and drawbacks of the combination of UV irradiation with electrolysis with the aim to give insight about the feasibility of the application of this technology for the reclaiming of conventionally-treated wastewater. The oxidation of synthetic solutions containing five selected model complex pollutants has been compared, showing that UV irradiation improves the results of electrolysis for progesterone, metoprolol and caffeine and deteriorates the performance for the degradation of sulfamethoxazole and dimethyl-phthalate. Differences observed becomes lower when mineralization is compared showing that the effects of UV irradiation are diluted when a mixture of species is oxidized. Results suggest that high ThOD/TOC (Theoretical Oxygen Demand/Total Organic Carbon) ratios improve the synergistic coupling of technologies while low values lead to a clear antagonistic effect. Because during oxidation progress this ratio is decreased, the observed effect on mineralization is much lower than in the oxidation of the raw molecule. Opposite to this low effect on the oxidation of organics, the improvement in the performance of the disinfection by coupling UV to electrolysis is much clearer. In addition, UV irradiation modifies significantly the chlorine speciation and helps to prevent the formation of hazardous species such as chlorate and perchlorate during the electrochemical processes.

  7. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process. (United States)

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


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

  8. Studying the processes of sulphates and chlorides extraction from water at low-waste water demineralization technology

    Directory of Open Access Journals (Sweden)

    Inna M. Тrus


    Full Text Available To solve the disposal problem of high-salinity liquid wastes resulting from the water demineralization, researched are the processes of chlorides’ and sulphates’ ion-exchange separation with further sulphates (in the form of calcium sulphate removal from the technological cycle. It is shown that the desulphatized water can be effectively desalinated by reverse osmosis filters, including low-pressure membranes Filmtec TW30-1812-50. The liquid waste obtained in form of concentrates, does contain chlorides, sodium ions and hardness ions. Established is that at these concentrates processing by lime and sodium carbonate or alkali and sodium carbonate they are softened with hardness decrease up to 0,25…0,95 mg-eq/dm3, which allows these solutions’ further electrolysis to obtain alkali and hydrochloric acid. Through direct electrolysis of concentrates, obtained by reverse osmosis water desalination at anionic membrane two-chamber electrolysers, we obtained a disinfectant solution containing chlorine oxigenates (active chlorine, hypochlorite, chlorite and sodium chlorate and duly effective in water sterilization. The resulting solution well keeps its properties and is promising for disinfection of natural and waste waters.

  9. Consumers’ perception and knowledge of food safety: results of questionnaires accessible on IZSalimenTO website

    Directory of Open Access Journals (Sweden)

    Amaranta Traversa


    Full Text Available The present survey was undertaken to investigate consumers’ knowledge of the main foodborne agents and dietary regimen during pregnancy. Data were collected using monthly questionnaires available on IZSalimenTO website between March 2013 and January 2014. Hepatitis A virus questionnaire: 20 respondents (77% recognized berries as foodstuff linked to the outbreak of hepatitis A. The majority correctly indicated as precautionary advice to boil berries before consumption. Botulism questionnaire: 29 respondents (62% indicated pesto as food involved in botulism alert in July 2013. The risk of infant botulism in infant less than 1 year old due to honey consumption is known by 24 respondents (51%. Main foodborne disease questionnaire: the risk of infection by Salmonella after the consumption of foods made with raw eggs is known by the majority (94%; N=17 as well as the treatments to be applied in order to make fresh fish safe from parasites (76%. Pregnancy questionnaire: 20 respondents (74% believed that washing vegetables and fruits with sodium bicarbonate or chlorate solution is able to inactivate Toxoplasma; only 4 (15% reported both raw meat and vegetables washed with sodium bicarbonate as food at risk. Results indicate that all consumers should be trained on behaviour and dietary regimen to be adopted in pregnancy and in infant <1 year old. The website may be considered as a useful tool to assess consumers’ knowledge: both the news section and the contents published may be a source of information and education for consumers on food safety.

  10. Kinetics study of leaching arsenic from Ni-Mo ore roasting in dust mixture of hydrochloric and sulfuric acids

    Institute of Scientific and Technical Information of China (English)

    侯晓川; 杨润德; 李贺; 曾理; 肖连生


    The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated. The effects including leaching temperature, particle size of the smelter dust, stirring speed, the coefficientβ(the molar ratio of sodium chlorate to arsenic in the smelter dust) and the initial H+ concentration on leaching arsenic were studied. The results indicate that the leaching of arsenic increases sharply with the decrease of particle size. The orders of reaction with respect to H+ concentration and particle size are determinted to be 1.136 and-1.806, respectively.The leaching of arsenic reaches 99% under experimental conditions, the apparent activation energy is determined to be 11.157 kJ/mol, which is consistent with the values of activation energy for diffusion model. The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η-(1-η)2/3=k0(c[H+])1.136r0-1.806exp[(-11157/RT)t].

  11. Vanadium recovery from clay vanadium mineral using an acid leaching method

    Institute of Scientific and Technical Information of China (English)

    LI Haoran; FENG Yali; LIANG Jianglong; LUO Xiaobing; DU Zhuwei


    A technique including direct acid leaching,vanadium precipitation with alkaline,sodium hydroxide releaching,impurity removing by adjusting pH value,precipitation vanadium with ammonium chloride,and vanadium pentoxide by roasting steps was proposed according to the characteristic of Xichuan clay vanadium mineral.The factors influencing leaching vanadium such as temperature and the concentration of sulfuric acid were investigated and optimized.The experimental results indicate that the extract ratios of V2O5 can reach 94% and 92% at a sodium chlorate ratio of 3% and a manganese dioxide ratio of 3%,respectively.A completely chemical precipitation method was adopted to decontaminate and enrich the vanadium in the acid leaching solution.The X-ray diffraction (XRD) pattern and the purity analysis of vanadium pentoxide indicate that the purity of final vanadium pentoxide can reach 99% and meet the standard specifications.The total recovery can reach about 75%.The technique has the characteristics of simplicity,less investlnent,and more environment safety as compared with the traditional salt roasting method.

  12. MEMS-Based Solid Propellant Rocket Array Thruster (United States)

    Tanaka, Shuji; Hosokawa, Ryuichiro; Tokudome, Shin-Ichiro; Hori, Keiichi; Saito, Hirobumi; Watanabe, Masashi; Esashi, Masayoshi

    The prototype of a solid propellant rocket array thruster for simple attitude control of a 10 kg class micro-spacecraft was completed and tested. The prototype has 10×10 φ0.8 mm solid propellant micro-rockets arrayed at a pitch of 1.2 mm on a 20×22 mm substrate. To realize such a dense array of micro-rockets, each ignition heater is powered from the backside of the thruster through an electrical feedthrough which passes along a propellant cylinder wall. Boron/potassium nitrate propellant (NAB) is used with/without lead rhodanide/potassium chlorate/nitrocellulose ignition aid (RK). Impulse thrust was measured by a pendulum method in air. Ignition required electric power of at least 3 4 W with RK and 4 6 W without RK. Measured impulse thrusts were from 2×10-5 Ns to 3×10-4 Ns after the calculation of compensation for air dumping.

  13. Removal of NO from flue gas by aqueous chlorine-dioxide scrubbing solution in a lab-scale bubbling reactor

    Energy Technology Data Exchange (ETDEWEB)

    Deshwal, Bal Raj [Department of Chemistry, A.I.J.H.M. College, Rohtak 124001, Haryana (India); Jin, Dong Seop; Lee, Si Hyun; Moon, Seung Hyun [Korea Institute of Energy Research, Daejon 305 600 (Korea, Republic of); Jung, Jong Hyeon [Department of Environmental Engineering, Sorabol College, Kyungbuk - 780 711 (Korea, Republic of); Lee, Hyung Keun [Korea Institute of Energy Research, Daejon 305 600 (Korea, Republic of)], E-mail:


    The present study attempts to clean up nitric oxide from the simulated flue gas using aqueous chlorine-dioxide solution in the bubbling reactor. Chlorine-dioxide is generated by chloride-chlorate process. Experiments are carried out to examine the effect of various operating variables like input NO concentration, presence of SO{sub 2}, pH of the solution and NaCl feeding rate on the NO{sub x} removal efficiency at 45 deg. C. Complete oxidation of nitric oxide into nitrogen dioxide occurred on passing sufficient ClO{sub 2} gas into the scrubbing solution. NO is finally converted into nitrate and ClO{sub 2} is reduced into chloride ions. A plausible reaction mechanism concerning NO{sub x} removal by ClO{sub 2} is suggested. DeNO{sub x} efficiency increased slightly with the increasing input NO concentration. The presence of SO{sub 2} improved the NO{sub 2} absorption but pH of solution showed marginal effect on NO{sub 2} absorption. NO{sub x} removal mechanism changed when medium of solution changed from acidic to alkaline. A constant NO{sub x} removal efficiency of about 60% has been achieved in the wide pH range of 3-11 under optimized conditions.

  14. Simultaneous removal of SO{sub 2} and NO by wet scrubbing using aqueous chlorine dioxide solution

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Dong-Seop [Flue Gas Treatment Center, Korea Institute of Energy Research, Daejon 305 600 (Korea, Republic of); Deshwal, Bal-Raj [Department of Chemistry, A.I.J.H.M. College, Rohtak 124001, Haryana (India)]. E-mail:; Park, Young-Seong [Department of Environmental Engineering, Daejon University, Daejon (Korea, Republic of); Lee, Hyung-Keun [Flue Gas Treatment Center, Korea Institute of Energy Research, Daejon 305 600 (Korea, Republic of)


    The present study attempts to generate chlorine dioxide (ClO{sub 2}) gas continuously by chlorate-chloride process and to utilize it further to clean up SO{sub 2} and NO {sub x} gases simultaneously from the flue gas in the lab-scale bubbling reactor. Experiments were carried out to examine the effect of various operating parameters like input SO{sub 2} concentration, input NO concentration, pH of the reaction medium, and ClO{sub 2} feeding rate on the SO{sub 2} and NO {sub x} removal efficiencies at 45 deg. C. Complete oxidation of NO into NO{sub 2} occurred on passing sufficient ClO{sub 2} gas into the scrubbing solution. SO{sub 2} removal efficiency of about 100% and NO {sub x} removal efficiency of 66-72% were achieved under optimized conditions. NO {sub x} removal efficiency decreased slightly with increasing pH and NO concentration. Input SO{sub 2} concentration had marginal catalytic effect on NO{sub 2} absorption. No improvement in the NO {sub x} removal efficiency was observed on passing excess of chlorine dioxide in the scrubbing solution.

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

    Energy Technology Data Exchange (ETDEWEB)

    Butters, G.


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

  16. Monochloramine and chlorine dioxide for controlling Legionella pneumophila contamination: biocide levels and disinfection by-product formation in hospital water networks. (United States)

    Marchesi, Isabella; Ferranti, Greta; Bargellini, Annalisa; Marchegiano, Patrizia; Predieri, Guerrino; Stout, Janet E; Borella, Paola


    Legionella colonization in hospital hot water distribution networks was evaluated following 36 months of continuous treatment with monochloramine and compared with chlorine dioxide. Nitrite, nitrate, chlorite, chlorate, bromide, trihalomethanes and haloacetic acids as well as the biocide concentration at sampled points were measured. Only 8/84 samples treated with monochloramine were found contaminated and after the first 8 months of treatment no Legionella was isolated. Chlorine dioxide was associated with a strong reduction in Legionella contamination compared to pre-treatment, but differences according to the device were observed. Monochloramine between 2 and 3 mg l(-1) and chlorine dioxide between 0.50 and 0.70 mg l(-1) were needed to control Legionella colonization. Comparing no- and post-flush samples, a higher frequency of no-flush positive samples was noted using chlorine dioxide, suggesting an increased risk for patients when they open the tap. No increase in chlorite levels and no water nitrification occurred by using monochloramine. Chlorite at levels exceeding the limit requested for drinking water was measured when chlorine dioxide was applied. In conclusion, we highlight that continuous injection of monochloramine should be considered as an effective alternative to chlorine dioxide in controlling legionellae contamination inside hospital water distribution systems.

  17. “Development of an Automated On-line Electrochemical Chlorite Ion Sensor” (United States)

    Myers, John N.; Steinecker, William H.; Sandlin, Zechariah D.; Cox, James A.; Gordon, Gilbert; Pacey, Gilbert E.


    A sensor system for the automatic, in-line, determination of chlorite ion is reported. Electroanalytical measurements were performed in electrolyte-free liquids by using an electrochemical probe (EC), which enables in-line detection in high-resistance media such as disinfected water. Cyclic voltammetry scan rate studies suggest that the current arising from the oxidation of chlorite ion at an EC probe is mass-transfer limited. By coupling FIA with an EC probe amperometric cell, automated analysis was achieved. This sensor is intended to fulfill the daily monitoring requirements of the EPA DBP regulations for chlorite ion. Detection limits of 0.02-0.13 mg/L were attained, which is about one order of magnitude below the MRDL. The sensor showed no faradaic signal for perchlorate, chlorate, or nitrate. The lifetime and stability of the sensor were investigated by measuring calibration curves over time under constant-flow conditions. Detection limits of <0.1 mg/L were repeatedly achieved over a period of three weeks. PMID:22608440

  18. Development of an automated on-line electrochemical chlorite ion sensor. (United States)

    Myers, John N; Steinecker, William H; Sandlin, Zechariah D; Cox, James A; Gordon, Gilbert; Pacey, Gilbert E


    A sensor system for the automatic, in-line, determination of chlorite ion is reported. Electroanalytical measurements were performed in electrolyte-free liquids by using an electrochemical probe (EC), which enables in-line detection in high-resistance media such as disinfected water. Cyclic voltammetry scan rate studies suggest that the current arising from the oxidation of chlorite ion at an EC probe is mass-transfer limited. By coupling FIA with an EC probe amperometric cell, automated analysis was achieved. This sensor is intended to fulfill the daily monitoring requirements of the EPA DBP regulations for chlorite ion. Detection limits of 0.02-0.13 mg/L were attained, which is about one order of magnitude below the MRDL. The sensor showed no faradaic signal for perchlorate, chlorate, or nitrate. The lifetime and stability of the sensor were investigated by measuring calibration curves over time under constant-flow conditions. Detection limits of <0.1 mg/L were repeatedly achieved over a period of three weeks.

  19. PLA-b-PEG/magnetite hyperthermic agent prepared by Ugi four component condensation

    Directory of Open Access Journals (Sweden)

    L. P. Icart


    Full Text Available Ugi four component condensation (UFCC, is an important tool for the synthesis of different types of bioconjugate species. In this study, a PLA-PEG/magnetite magnetic composite was prepared by a synthetic-route approach based on UFCC. In particular, poly(lactic acid (PLA was synthesized by autocatalytic polycondensation. Also, poly(ethyleneglycol bis-amine (bis-amine PEG was synthesized by two different methods: via carbonyldiimidazol (CDI/ethylenediamine (ED (75% yield and via chlorate monochlorated acetyl (CCA/ED (95% yield. All products were characterized by gel permeation chromatography (GPC, hydrogen-1 nuclear magnetic resonance (NMR 1H, Fourier transform infrared (FTIR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA. In addition, magnetite was prepared and modified to generate aldehyde groups which are also necessary for UFCC. This product was characterized by DSC, TGA, X-ray diffraction (XRD and magnetic force (MF techniques. Also, the magnetic composite PLA-PEG/magnetite was synthesized by UFCC. The calculated yield was equal to 80%. Furthermore, magnetic microspheres were prepared by the procedure of emulsion solvent-evaporation and characterized by scanning electron microscopy (SEM and magnetic induction hyperthermia (MIH. The main contribution of these results is to propose a new application for UFCC in the preparation of biomasked magnetic drug delivery systems able to improve the cancer treatment and even the welfare of the patients.

  20. Gene replacement in Penicillium roqueforti. (United States)

    Goarin, Anne; Silar, Philippe; Malagnac, Fabienne


    Most cheese-making filamentous fungi lack suitable molecular tools to improve their biotechnology potential. Penicillium roqueforti, a species of high industrial importance, would benefit from functional data yielded by molecular genetic approaches. This work provides the first example of gene replacement by homologous recombination in P. roqueforti, demonstrating that knockout experiments can be performed in this fungus. To do so, we improved the existing transformation method to integrate transgenes into P. roqueforti genome. In the meantime, we cloned the PrNiaD gene, which encodes a NADPH-dependent nitrate reductase that reduces nitrate to nitrite. Then, we performed a deletion of the PrNiaD gene from P. roqueforti strain AGO. The ΔPrNiaD mutant strain is more resistant to chlorate-containing medium than the wild-type strain, but did not grow on nitrate-containing medium. Because genomic data are now available, we believe that generating selective deletions of candidate genes will be a key step to open the way for a comprehensive exploration of gene function in P. roqueforti.

  1. Isolation and preliminary characterization of a respiratory nitrate reductase from hydrocarbon-degrading bacterium Gordonia alkanivorans S7. (United States)

    Romanowska, Irena; Kwapisz, Ewa; Mitka, Magdalena; Bielecki, Stanisław


    Gordonia alkanivorans S7 is an efficient degrader of fuel oil hydrocarbons that can simultaneously utilize oxygen and nitrate as electron acceptors. The respiratory nitrate reductase (Nar) from this organism has been isolated using ion exchange chromatography and gel filtration, and then preliminarily characterized. PAGE, SDS-PAGE and gel filtration chromatography revealed that Nar consisted of three subunits of 103, 53 and 25 kDa. The enzyme was optimally active at pH 7.9 and 40 degrees C. K(m) values for NO(3)(-) (110 microM) and for ClO(3)(-) (138 microM) were determined for a reduced viologen as an electron donor. The purified Nar did not use NADH as the electron donor to reduce nitrate or chlorate. Azide was a strong inhibitor of its activity. Our results imply that enzyme isolated from G. alkanivorans S7 is a respiratory membrane-bound nitrate reductase. This is the first report of purification of a nitrate reductase from Gordonia species.

  2. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues. (United States)

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D


    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth.

  3. Mirror Symmetry Breaking in Helical Polysilanes: Preference between Left and Right of Chemical and Physical Origin

    Directory of Open Access Journals (Sweden)

    Michiya Fujiki


    Full Text Available From elemental particles to human beings, matter is dissymmetric with respect to mirror symmetry. In 1860, Pasteur conjectured that biomolecular handedness— homochirality—may originate from certain inherent dissymmetric forces existing in the universe. Kipping, a pioneer of organosilicon chemistry, was interested in the handedness of sodium chlorate during his early research life. Since Kipping first synthesized several Si-Si bonded oligomers bearing phenyl groups, Si-Si bonded high polymers carrying various organic groups—polysilanes—can be prepared by sodium-mediated condensation of the corresponding organodichlorosilanes. Among these polysilanes, optically active helical polysilanes with enantiomeric pairs of organic side groups may be used for testing the mirror symmetry-breaking hypothesis by weak neutral current (WNC origin in the realm of chemistry and material science. Several theoretical studies have predicted that WNC-existing chiral molecules with stereogenic centers and/or stereogenic bonds allow for distinguishing between image and mirror image molecules. Based on several amplification mechanisms, theorists claimed that minute differences, though still very subtle, may be detectable by precise spectroscopic and physicochemical measurements if proper chiral molecular pairs were employed. The present paper reports comprehensively an inequality between six pairs of helical polysilane high polymers, presumably, detectable by (chiroptical and achiral 29Si-/13C- NMR spectra, and viscometric measurements.

  4. Glycosaminoglycans in human retinoblastoma cells: Heparan sulfate, a modulator of the pigment epithelium-derived factor-receptor interactions (United States)

    Alberdi, Elena M; Weldon, John E; Becerra, S Patricia


    Background Pigment epithelium-derived factor (PEDF) has binding affinity for cell-surface receptors in retinoblastoma cells and for glycosaminoglycans. We investigated the effects of glycosaminoglycans on PEDF-receptor interactions. Results 125I-PEDF formed complexes with protease-resistant components of medium conditioned by human retinoblastoma Y-79 cells. Using specific glycosaminoglycan degrading enzymes in spectrophotometric assays and PEDF-affinity chromatography, we detected heparin and heparan sulfate-like glycosaminoglycans in the Y-79 conditioned media, which had binding affinity for PEDF. The Y-79 conditioned media significantly enhanced the binding of 125I-PEDF to Y-79 cell-surface receptors. However, enzymatic and chemical depletion of sulfated glycosaminoglycans from the Y-79 cell cultures by heparitinase and chlorate treatments decreased the degree of 125I-PEDF binding to cell-surface receptors. Conclusions These data indicate that retinoblastoma cells secrete heparin/heparan sulfate with binding affinity for PEDF, which may be important in efficient cell-surface receptor binding. PMID:12625842

  5. Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites (United States)

    Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S.; Pantoya, M. L.


    Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300-2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%-1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.

  6. Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

    Energy Technology Data Exchange (ETDEWEB)

    Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Pantoya, M. L. [Mechanical Engineering Department, Texas Tech University, Lubbock, Texas 79409 (United States)


    Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300–2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.

  7. Thermal Decomposition of Calcium Perchlorate/Iron-Mineral Mixtures: Implications of the Evolved Oxygen from the Rocknest Eolian Deposit in Gale Crater, Mars (United States)

    Bruck, A. M.; Sutter, B.; Ming, D. W.; Mahaffy, P.


    A major oxygen release between 300 and 500 C was detected by the Mars Curiosity Rover Sample Analysis at Mars (SAM) instrument at the Rocknest eolian deposit. Thermal decomposition of perchlorate (ClO4-) salts in the Rocknest samples are a possible explanation for this evolved oxygen release. Releative to Na-, K-, Mg-, and Fe-perchlorate, the thermal decomposition of Ca-perchlorate in laboratory experiments released O2 in the temperature range (400-500degC) closest to the O2 release temperatures observed for the Rocknest material. Furthermore, calcium perchlorate could have been the source of Cl in the chlorinated-hydrocarbons species that were detected by SAM. Different components in the Martian soil could affect the decomposition temperature of calcium per-chlorate or another oxychlorine species. This interaction of the two components in the soil could result in O2 release temperatures consistent with those detected by SAM in the Rocknest materials. The decomposition temperatures of various alkali metal perchlorates are known to decrease in the presence of a catalyst. The objective of this work is to investigate catalytic interactions on calcium perchlorate from various iron-bearing minerals known to be present in the Rocknest material

  8. Proton and deuterium NMR experiments in zero field. [Perdeuterated p-demethoxybenzene, perdeuterated malonic acid, diethyl terephthalate-d4, nonadecane-2,2'-D2, sodium propionate-D2

    Energy Technology Data Exchange (ETDEWEB)

    Millar, J.M.


    High field solid-state NMR lineshapes suffer from inhomogeneous broadening since resonance frequencies are a function of molecular orientation. Time domain zero field NMR is a two-dimensional field-cycling technique which removes this broadening by probing the evolution of the spin system under zero applied field. The simplest version, the sudden transition experiment, induces zero field evolution by the sudden removal of the applied magnetic field. Theory and experimental results of this experiment and several variations using pulsed dc magnetic fuelds to initiate zero field evolution are presented. In particular, the pulsed indirect detection method allows detection of the zero field spectrum of one nuclear spin species via another (usually protons) by utilizing the level crossings which occur upon adiabatic demagnetization to zero field. Experimental examples of proton/deuteron systems are presented which demonstrate the method results in enhanced sensitivity relative to that obtained in sudden transition experiments performed directly on deuterium. High resolution /sup 2/H NQR spectra of a series of benzoic acid derivatives are obtained using the sudden transition and indirect detection methods. Librational oscillations in the water molecules of barium chlorate monohydrate are studied using proton and deuterium ZF experiments. 177 refs., 88 figs., 2 tabs.

  9. On the suppression of cathodic hypochlorite reduction by electrolyte additions of molybdate and chromate ions

    Directory of Open Access Journals (Sweden)



    Full Text Available The goal of this study was to gain a better understanding of the feasibility of replacing Cr(VI in the chlorate process by Mo(VI, focusing on the cathode reaction selectivity for hydrogen evolution on steel and titanium in a hypochlorite containing electrolyte. To evaluate the ability of Cr(VI and Mo(VI additions to hinder hypochlorite reduction, potential sweep experiments on rotating disc electrodes and cathodic current efficiency (CE measurements on stationary electrodes were performed. Formed electrode films were investigated with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cathodic hypochlorite reduction is hindered by the Mo-containing films formed on the cathode surface after Mo(VI addition to the electrolyte, but much less efficient compared to Cr(VI addition. Very low levels of Cr(VI, in the mM range, can efficiently suppress hypochlorite reduction on polished titanium and steel. Phosphate does not negatively influence the CE in the presence of Cr(VI or Mo(VI but the Mo-containing cathode films become thinner if the electrolyte during the film build-up also contains phosphate. For a RuO2-TiO2 anode polarized in electrolyte with 40 mM Mo(VI, the anode potential increased and increased molybdenum levels were detected on the electrode surface

  10. Entamoeba mitosomes play an important role in encystation by association with cholesteryl sulfate synthesis. (United States)

    Mi-ichi, Fumika; Miyamoto, Tomofumi; Takao, Shouko; Jeelani, Ghulam; Hashimoto, Tetsuo; Hara, Hiromitsu; Nozaki, Tomoyoshi; Yoshida, Hiroki


    Hydrogenosomes and mitosomes are mitochondrion-related organelles (MROs) that have highly reduced and divergent functions in anaerobic/microaerophilic eukaryotes. Entamoeba histolytica, a microaerophilic, parasitic amoebozoan species, which causes intestinal and extraintestinal amoebiasis in humans, possesses mitosomes, the existence and biological functions of which have been a longstanding enigma in the evolution of mitochondria. We previously demonstrated that sulfate activation, which is not generally compartmentalized to mitochondria, is a major function of E. histolytica mitosomes. However, because the final metabolites of sulfate activation remain unknown, the overall scheme of this metabolism and the role of mitosomes in Entamoeba have not been elucidated. In this study we purified and identified cholesteryl sulfate (CS) as a final metabolite of sulfate activation. We then identified the gene encoding the cholesteryl sulfotransferase responsible for synthesizing CS. Addition of CS to culture media increased the number of cysts, the dormant form that differentiates from proliferative trophozoites. Conversely, chlorate, a selective inhibitor of the first enzyme in the sulfate-activation pathway, inhibited cyst formation in a dose-dependent manner. These results indicate that CS plays an important role in differentiation, an essential process for the transmission of Entamoeba between hosts. Furthermore, we show that Mastigamoeba balamuthi, an anaerobic, free-living amoebozoan species, which is a close relative of E. histolytica, also has the sulfate-activation pathway in MROs but does not possess the capacity for CS production. Hence, we propose that a unique function of MROs in Entamoeba contributes to its adaptation to its parasitic life cycle.

  11. A positively charged silver nanowire membrane for rapid on-site swabbing extraction and detection of trace inorganic explosives using a portable Raman spectrometer

    Institute of Scientific and Technical Information of China (English)

    Yu-e Shi; Wenshou Wang; Jinhua Zhan


    The sensitive and on-site detection of inorganic explosives has raised serious concerns regarding public safety.However,high stability and non-volatility features currently limit their rapid on-site detection.Surface-enhanced Raman spectroscopy (SERS) is emerging as a powerful technique for the trace-level detection of different molecules.Plasmonic Ag nanowires were produced by a hydrothermal synthesis method using polyvinylpyrrolidone (PVP) as a negatively charged stabilizer.Here,we report a rapid detection method for inorganic explosives based on a simple surface swab with a positively charged diethyldithiocarbamate-modified Ag nanowire membrane coupled with SERS.This membrane,serving as an excellent SERS substrate with high uniformity,stability,and reusability,can capture both typical oxidizers in inorganic explosives and organic nitro-explosives,via electrostatic interaction.The detection level of perchlorates (ClO4-),chlorates (ClO3-),nitrates (NO3-),picric acid,and 2,4-dinitrophenol is as high as 2.0,1.7,0.1,45.8,and 36.6 ng,respectively.In addition,simulated typical inorganic explosives such as black powders,firecrackers,and match heads could also be detected.We believe that this membrane represents an attractive alternative for rapid on-site detection of inorganic explosives with high efficiency.

  12. Recovery of Co(Ⅱ) and Ni(Ⅱ) from hydrochloric acid solution of alloy scrap

    Institute of Scientific and Technical Information of China (English)

    SHEN Yong-feng; XUE Wen-ying; NIU Wen-yong


    A hydrometallurgical process was developed for recovery of nickel and cobalt from the hydrochloric acid leaching solution of alloy scraps. The process consists of five major unit operations: 1) leaching with 6 mol/L hydrochloric acid under the L/S ratio of 10:1 at 95 ℃ for 3 h; 2) copper replacement by iron scraps under pH value of 2.0 at 80 ℃, and stirring for 1 h; 3) removal of iron and chromium by chemical precipitation: iron removal under pH value of 2.0 at 90 ℃ by dropwise addition of sodium chlorate and 18% sodium carbonate solution, then chromium removal under pH value of 4.0 at 70 ℃ by addition of nickel carbonate solution, stirred by air flow for 2 h; 4) selective separation of cobalt from nickel by extraction using 30% trialkyl amine+50% kerosene (volume fraction) and tri-n-butylphosphate (TBP) as a phase modifier with the O/A ratio of 2:1, and stripping of cobalt with 0.01 mol/L HC1; 5) crystallization of nickel chloride and electrodeposition of cobalt. It is found that the nickel recovery of 95% and the cobalt recovery of approximately 60% with purity over 99.9% are obtained by this process.

  13. Electrochemical disinfection using boron-doped diamond electrode--the synergetic effects of in situ ozone and free chlorine generation. (United States)

    Rajab, Mohamad; Heim, Carolin; Letzel, Thomas; Drewes, Jörg E; Helmreich, Brigitte


    This work investigated the capability of using a boron-doped diamond (BDD) electrode for bacterial disinfection in different water matrices containing varying amounts of chloride. The feed water containing Pseudomonas aeruginosa was electrochemically treated while applying different electrode conditions. Depending on the applied current density and the exposure time, inactivation between 4- and 8-log of the targeted microorganisms could be achieved. The disinfection efficiency was driven by the generation of free chlorine as a function of chloride concentration in the water. A synergetic effect of generating both free chlorine and ozone in situ during the disinfection process resulted in an effective bactericidal impact. The formation of the undesired by-products chlorate and perchlorate depended on the water matrix, the applied current density and the desired target disinfection level. In case of synthetic water with a low chloride concentration (20 mg L(-1)) and an applied current density of 167 mA cm(-2), a 6-log inactivation of Pseudomonas aeruginosa could be achieved after 5 min of exposure. The overall energy consumption ranged between 0.3 and 0.6 kW h m(-3) depending on the applied current density and water chemistry. Electrochemical water disinfection represents a suitable and efficient process for producing pathogen-free water without the use of any chemicals.

  14. 氯酸钾体系催化动力学光度法测定痕量钒(Ⅱ)%Catalytic kinetic spectrophotometric determination of trace vanadium

    Institute of Scientific and Technical Information of China (English)

    沈淑君; 邹小勇


    A new catalytic kinetic spectrophotometry was presented for the determination of trace vanadium ( V ).The catalytic effect was investigated for vanadium ( V ) on the oxidation of methyl red( C15H15N3O2 )by potassium chlorate ( KClO3 ) with ascorbic acid ( C6 Hg O6 ) as an activating agent in phosphoric acid solution (0.1 mol/L). The linear range is 0.09 ~ 7.0 ng/mL and the detection limit is 2.9 × 10 -2ng/mL. The proposed method has been successfully applied to the determination of vanadium ( V ) in water and food samples, and the satisfactory results were obtained.%研究了在0.1mol/LH3PO4介质中,活化剂抗坏血酸的作用下,V(Ⅴ)催化KClO3氧化甲基红褪色的指示反应,由此建立了一种测定痕量V(Ⅱ)的催化动力学光度新方法.研究了影响该催化褪色反应的因素.方法的线性范围为0.09~7.0ng/mL,检出限为2.9×10-2ng/mL.方法用于实际样品的测定.

  15. Organic acids and inorganic anions in Bayer liquors by ion chromatography after solid-phase extraction

    Institute of Scientific and Technical Information of China (English)

    ZHONG Fu-jin; CHEN Xiao-qing; ZHANG Shu-chao; LI Yue-ping


    A method for the simultaneous separation and determination of organic acids and inorganic anions in Bayer liquors was developed by gradient ion chromatography with suppressed conductivity detection. Formate, acetate, propionate, oxalate, succinate,glutarate, fluoride, chloride and sulfate were separated and determined in 33 min. The samples were pretreated with solid-phase extraction, which has high selectivity for removing a large number of metallic ions in the Bayer liquors, and filtered with a 0.45 μm filter membrane before being injected into the ion chromatographic system. The separation of six organic acids and three inorganic anions was achieved on an IonPac AS11-HC column with KOH as the eluent, and the detection was performed by a conductivity detection mode. No interference is found in the presence of fluorate, chlorate and sulphate when organic acids are determined. The calibration graphs of peak area for all the analytes are linear over a wide range. The relative standard derivation of the peak area of analytes is less than 2.14%. Under optimum conditions the detection ranges from 0.2 to 100.0 mg/L. The average recoveries of the added standards are between 94.3% and 102.8%.

  16. Determining the effects of routine fingermark detection techniques on the subsequent recovery and analysis of explosive residues on various substrates. (United States)

    King, Sam; Benson, Sarah; Kelly, Tamsin; Lennard, Chris


    An offender who has recently handled bulk explosives would be expected to deposit latent fingermarks that are contaminated with explosive residues. However, fingermark detection techniques need to be applied in order for these fingermarks to be detected and recorded. Little information is available in terms of how routine fingermark detection methods impact on the subsequent recovery and analysis of any explosive residues that may be present. If an identifiable fingermark is obtained and that fingermark is found to be contaminated with a particular explosive then that may be crucial evidence in a criminal investigation (including acts of terrorism involving improvised explosive devices). The principal aims of this project were to investigate: (i) the typical quantities of explosive material deposited in fingermarks by someone who has recently handled bulk explosives; and (ii) the effects of routine fingermark detection methods on the subsequent recovery and analysis of explosive residues in such fingermarks. Four common substrates were studied: paper, glass, plastic (polyethylene plastic bags), and metal (aluminium foil). The target explosive compounds were 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), as well as chlorate and nitrate ions. Recommendations are provided in terms of the application of fingermark detection methods on surfaces that may contain explosive residues.

  17. Evidence for the Role of Proteoglycans in Cation-Mediated Gene Transfer (United States)

    Mislick, Kimberly A.; Baldeschwieler, John D.


    We report evidence that gene complexes, consisting of polycations and plasmid DNA enter cells via binding to membrane-associated proteoglycans. Treatment of HeLa cells with sodium chlorate, a potent inhibitor of proteoglycan sulfation, reduced luciferase expression by 69%. Cellular treatment with heparinase and chondroitinase ABC inhibited expression by 78% and 20% with respect to control cells. Transfection was dramatically inhibited by heparin and heparan sulfate and to a smaller extent by chondroitan sulfate B. Transfection of mutant, proteoglycan deficient Chinese hamster ovary cells was 53× lower than of wild-type cells. For each of these assays, the intracellular uptake of DNA at 37 degrees C and the binding of DNA to the cell membrane at 4 degrees C was impaired. Preliminary transfection experiments conducted in mutant and wild-type Chinese hamster ovary cells suggest that transfection by some cationic lipids is also proteoglycan dependent. The variable distribution of proteoglycans among tissues may explain why some cell types are more susceptible to transfection than others.

  18. Oxychlorine Detections on Mars: Implications for Cl Cycling (United States)

    Sutter, B.; Jackson, W. A.; Ming, D. W.; Archer, P. D.; Stern, J. C.; Mahaffy, P. R.; Gellert, R.


    The Sample Analysis at Mars (SAM) instrument has detected evolved O2 and HCl indicating the presence of perchlorate and/or chlorate (oxychlorine) in all 11 sediments analyzed to date. The hyperarid martian climate is believed to have allowed accumulation of oxychlorine and assumed chloride contents similar to those in hyperarid terrestrial settings. The linear correlation of oxychlorine and chloride of Gale Crater sediments is low (r (sup 2) equals 0.64). Correlations present in hyperarid Antarctica and the Atacama Desert are attributed to unaltered atmospheric source coupled with minimal redox cycling by biological activity. Terrestrial semi-arid to arid settings have low correlations similar to Gale Crater and are attributed to additional inputs of Cl minus from sea salt, dust, and/or proximal playa settings, and possible reduction of oxychlorine phases during wetter periods. While microbiological processes could contribute to low oxychlorine/chloride correlations on Mars, several abiotic mechanisms are more likely, such as changing oxychlorine production rates with time and/or post-depositional geochemical redox processes that altered the Gale Crater oxychlorine and chloride contents.

  19. Pilot scale performance of the electro-oxidation of landfill leachate at boron-doped diamond anodes. (United States)

    Anglada, Angela; Urtiaga, Ane; Ortiz, Inmaculada


    During the electrochemical oxidation of real wastewaters, the different species present in the effluent may interact creating complex scenarios making the prediction of the behavior of the whole system difficult. In this paper the different phenomena that occur during the electro-oxidation process of landfill leachate at a pilot plant scale with boron-doped diamond (BDD) anodes are elucidated. The total BDD anode area of the pilot plant was 1.05 m2. The evolution of the concentration of chloride ions, chlorate, and inorganic carbon and the value of pH and redox potential were found to be inter-related. In turn, the concentration of chloride affected the oxidation of ammonia, which took place through indirect oxidation by active chlorine. Moreover, chloride ions competed with organic matter to be oxidized at the anode. The effect of current density was also investigated. Organic matter and ammonia oxidation were highly influenced by the applied current density value. A change in the mechanism of organic matter oxidation was observed when high current densities were applied. Two mathematical models, previously applied to the oxidation of synthetic wastewaters in the literature, were able to predict the evolution of chemical oxygen demand and ammonia for low current density values.

  20. Water-Quality Constituents, Dissolved-Organic-Carbon Fractions, and Disinfection By-Product Formation in Water from Community Water-Supply Wells in New Jersey, 1998-99 (United States)

    Hopple, Jessica A.; Barringer, Julia L.; Koleis, Janece


    to a pH of 7, dosed with sodium hypochlorite, and incubated for 168 hours (seven days) at 25 ?C to form disinfection by-products (DBPs). Concentrations of the DBPs-trihalomethanes, haloacetic acids, haloacetonitriles, and chlorate-were measured. Concentrations of these compounds, with few exceptions, were higher in water from Coastal Plain wells than from wells in glacial and bedrock aquifers. The organic-carbon fractions were dosed with sodium hypochlorite, incubated for 168 hours at 25 ?C, and analyzed for trihalomethanes, haloacetic acids, haloacetonitriles, and chlorate. Concentrations of trihalomethanes and haloacetic acids were higher in most of the hydrophobic organic-acid fractions than in the hydrophilic fractions, with the highest concentrations in samples from Coastal Plain aquifers. Traces of haloacetonitriles were measured, mostly in the hydrophilic fraction. The aromaticity of the precursor DOC, as estimated by measurements of the absorbance of ultraviolet light at 254 nanometers, apparently is a factor in the DBP formation potentials determined, as aromaticity was greater in the samples that developed high concentrations of DBPs. VOCs may have contributed to the organic carbon present in some of the samples, but much of the DOC present in water from the 20 wells appeared to be natural in origin. The sediments of the Coastal Plain aquifers, in particular, contain substantial amounts of organic matter, which contribute ammonia, organic nitrogen, and aromatic DOC compounds to the ground water. Thus, the geologic characteristics of the aquifers appear to be a major factor in the potential for ground water to form DBPs when chlorinated.

  1. Dissimilatory perchlorate reduction linked to aerobic methane oxidation via chlorite dismutase (United States)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.


    The presence of methane (CH4) in the atmosphere of Mars is controversial yet the evidence has aroused scientific interest, as CH4 could be a harbinger of extant or extinct microbial life. There are various oxidized compounds present on the surface of Mars that could serve as electron acceptors for the anaerobic oxidation of CH4, including perchlorate (ClO4-). We examined the role of perchlorate, chlorate (ClO3-) and chlorite (ClO2-) as oxidants linked to CH4 oxidation. Dissimilatory perchlorate reduction begins with reduction of ClO4- to ClO2- and ends with dismutation of chlorite to yield chloride (Cl-) and molecular oxygen (O2). We explored the potential for aerobic CH4 oxidizing bacteria to couple with oxygen derived from chlorite dismutation during dissimilatory perchlorate reduction. Methane (0.2 kPa) was completely removed within several days from the N2-flushed headspace above cell suspensions of methanotrophs (Methylobacter albus strain BG8) and perchlorate reducing bacteria (Dechloromonas agitata strain CKB) in the presence of 5 mM ClO2-. Similar rates of CH4 consumption were observed for these mixed cultures whether they were co-mingled or segregated under a common headspace, indicating that direct contact of cells was not required for methane consumption to occur. We also observed complete removal of 0.2 kPa CH4 in bottles containing dried soil (enriched in methanotrophs by CH4 additions over several weeks) and D. agitata CKB and in the presence of 10 mM ClO2-. This soil (seasonally exposed sediment) collected from the shoreline of a freshwater lake (Searsville Lake, CA) demonstrated endogenous CH4 uptake as well as perchlorate, chlorate and chlorite reduction/dismutation. However, these experiments required physical separation of soil from the aqueous bacterial culture to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although dissimilatory reduction of ClO4- and ClO3- could be inferred from the

  2. "Let's take back our roots through Science". The Sicilian Sulfur: a mineralogical treasure to rediscover. (United States)

    Parisi, Bianca


    The name of sulfur is synonymous of Sicily! Sicilian Sulfur minerals and evaporitic deposits are well-known because they are connected with an important evolution stage of the old mediterranean area. In this Island, in the southern part of Italy, a geological formation of Messinian age, called "gessoso solfifera", outcrops. These rocks are widespread in the south and south-west Sicily, and, there, salt mines and "zolfare", sulfur mines, were located. The formation is characterized by large amounts of gypsum, potassium salts, sodium chlorates and other deposits. Most of the main mineralogical museum collections all over the world have at least a sample of one of these minerals that are usually characterized by a high aesthetic quality. When I proposed a lesson on the origin of sulfur in evaporitic rocks, I realized that an important part of the hystory of our region was in danger to be forgotten by younger generation. The exploitation of this mineral resource in the past is strictly linked to the troubled social and cultural transformation of Sicily during the last century. Thus, this is a particularly suitable topic for a multidisciplinary approach. In cooperation with the Mineralogical Museum (SteBiCeF Department, University of Palermo), a learning project was proposed to a group of 4th year high school students. It has been carrying on in order to develop the knowledge of the geological and chemical features of evaporitic deposits and to promote scientific abilities together with a better understanding of social-environmental issues. Project aims and activities include: ➢ Solubility and saturation experiments to reconstruct a simplified model of minerals deposition ➢ Working in groups: collection of data about old geological outcrops and current evaporating basins where rocks are forming in the world as well as information on sicilian mines from literature and historical documents (video, interviews, pictures, newspapers and others) ➢ a guided tour of the

  3. Reactivity of NiO for 2,4-D degradation with ozone: XPS studies. (United States)

    Rodríguez, Julia L; Valenzuela, Miguel A; Poznyak, Tatiana; Lartundo, Luis; Chairez, Isaac


    2,4-Dichlorophenoxyacetic acid (2,4-D) is usually used as a refractory model compound that requires a prolonged reaction time for mineralization. In this study, we found that nickel oxide (NiO) significantly improved 2,4-D degradation and mineralization in reaction with ozone. Other metal oxides, such as titania, silica and alumina, were also tested in this reaction, so that, the mineralization degree was almost the same for all of them (ca. 25%), whereas NiO showed more than 60% in 1h. These outstanding results led us to study in more depth the role of NiO as catalyst in the degradation of 2,4-D. For instance, the optimum NiO loading amount was 0.3 g L(-1). The catalytic ozonation showed a high stability after three reaction cycles. With the aim of identifying the surface species responsible for the high activity of NiO, besides knowing the byproducts during the degradation of 2,4-D, XPS and HPLC were mainly used as analytical tools. According to the results, the mineralization of 2,4-D was directly influenced by the adsorbed chlorate organic compounds and oxalate group onto NiO. Therefore, NiO plays a true role as a catalyst forming surface compounds which are subsequently decomposed causing an increase in the mineralization efficiency. In addition, it was possible to identify several degradation byproducts (2,4-diclorophenol, glycolic, fumaric, maleic and oxalic acids) that were included in a rational reaction pathway. It was proposed that 2,4-D elimination in presence of NiO as catalyst is a combination of processes such as: conventional ozonation, indirect mechanism (OH) and surface complex formation.

  4. Possible Detection of Perchlorates by the Sample Analysis at Mars (SAM) Instrument: Comparison with Previous Missions (United States)

    Navarro-Gonzalex, Rafael; Sutter, Brad; Archer, Doug; Ming, Doug; Eigenbrode, Jennifer; Franz, Heather; Glavin, Daniel; McAdam, Amy; Stern, Jennifer; McKay, Christopher; Coll, Patrice; Cabane, Michel; Mahaffy, Paul; Conrad, Pamela; Martin-Torres, Francisco; Zorzano-Mier, Maria; Grotzinger, John


    The first chemical analysis of soluble salts in the soil was carried out by the Phoenix Lander in the Martian Arctic [1]. Surprisingly, chlorine was present as magnesium or calcium perchlorate at 0.4 to 0.6 percent. Additional support for the identification of perchlorate came from the evolved gas analysis which detected the release of molecular oxygen at 350-550C [1]. When Mars-like soils from the Atacama Desert were spiked with magnesium perchlorate (1 percent) and heated using the Viking GC-MS protocol, nearly all the organics were combusted but a small amount was chlorinated, forming chloromethane and dichloromethane [2]. These chlorohydrocarbons were detected by the Viking GC-MS experiments when the Martian soil was analyzed but they were considered to be terrestrial contaminants [3]. Reinterpretation of the Viking results suggests trichloromethane, and chloromethylpropene) detected both by SAM QMS and GC-MS derived from known Earth organic contaminants in the instrument [6]. Calcium perchlorate appears to be the best candidate for evolved O2 in the Rocknest samples at this time but other Cl species (e.g., chlorates) are possible and must be evaluated. The potential detection of perchlorates in Rocknest material adds weight to the argument that both Viking Landers measured signatures of perchlorates. Even if the source of the organic carbon detected is still unknown, the chlorine source was likely Martian. Two mechanisms have been hypothesized for the formation of soil perchlorate: (1) Atmospheric oxidation of chlorine; and (2) UV photooxidation of chlorides catalyzed by mineral catalysts [7]. The presence of soil perchlorates in the Martian surface has important implications for the detection of organics [2], carbonates [8] and nitrates [9] by SAM.

  5. Emprêgo de desfolhantes na cultura da batatinha The use of potato vine killers

    Directory of Open Access Journals (Sweden)

    O. J. Boock


    Full Text Available Uma das medidas que se impõem para a melhoria do estado de sanidade dos tubérculos de batatinha (Solanum tuberosum L., tanto para o consumo como principalmente para o plantio, é a destruição da folhagem com alguma antecedência à colheita normal Além dessa melhoria, tal prática permite colocar o produto no mercado antes das épocas das maiores safras obtendo-se maiores lucros. Neste trabalho são apresentados resultados obtidos com o emprêgo de desfolhantes físicos, químicos e mecânicos, para determinação dos mais eficientes nas condições locais. Tal prática, em relação ao estado de sanidade, principalmente quanto às moléstias de vírus e apodrecimentos devidos à requeima (Phytophthora infestans e pinta preta (Alternaria solani, será objeto de novos experimentos, utilizando-se como desfolhante aquêles que, neste trabalho, se mostraram mais eficientes e econômicos, como foi o casododinitro-orto-secundário-butil-fenol e do dínitro-cresol.This paper discusses the results of preliminary tests for determining the best way to kill the potato vine under the conditions of the State of São Paulo. Of the methods compared (cutting or flaming the vines, or spraying them with sodium chlorate, sodium arsenite, dinitro cresol or dinitro-o-sec-butyl phenol, spraying with the dinitro derivatives seemed to be the best. Further experiments are needed to observe the incidence of virus diseases and rots caused by Phytophthora infstans and Alternaria solani in the seed potatoes coming from fields treated with the latter products.

  6. Synthesis and Structural Characterization of Cu(pic)2[CO(NH2)2]2 and (picH2)2[Cu(pic)2(SCN)2

    Institute of Scientific and Technical Information of China (English)

    郭光华; 杨春; 周国伟; 郭国聪; 王明盛; 蔡丽珍; 吴阿青; 黄锦顺


    Two new compounds Cu(pic)2[CO(NH2)2]2 1 and (picH2)2[Cu(pic)2(SCN)2] 2 were prepared from the reaction of picolinic acid and copper(Ⅱ) per-chlorate by using carbamide to adjust pH=4 in the preparation of compound 1 and KSCN to adjust pH=6 in the preparation of 2. Crystal data for 1: monoclinic system, space group P21/n with a=7.441(1), b=14.291(2), c=7.790(1) A, β=95.855(2)°, V=824.0(2) A3, Dc=1.724 g/cm3, F(000)=438, C14H16N606Cu, Mr=427.87,μ(MoKα)=1.375 mm-1, Z=2 and the final R=0.0365 for 1164 observed reflections. Crystal data for 2: monoclinic system, space group P21/c with a=9.8237(3), b=10.0409(3), c=14.5867(2) A, β -= 104.190(2), V=1394.91(6) A3, Dc= 1.595 g/cm3, F(000)=686, C26H20N6O8S2Cu, Mr=672.14,μ(MoKα)=0.994 mm-1, Z=2 and the final R=0.0442 for .1651 observed reflections. The Cu(Ⅱ)atom in both 1 and 2 has a 4+2 elongated octahedral environment with the pic- ligands locating on the equatorial plane, and carbamide and SCN- occupying the axial sites, respectively. In compound 2,there also exist two protonated picolinate cations for charge balance.

  7. Sweet and Sour: Attenuating Sulfidogenesis in an Advective Flow Column System with Perchlorate or Nitrate Treatment (United States)

    Engelbrektson, A. L.; Hubbard, C. G.; Piceno, Y.; Boussina, A.; Jin, Y.; Dubinsky, E. A.; Tom, L.; Hu, P.; Conrad, M. E.; Anderson, G. L.; Coates, J. D.


    Hydrogen sulfide (H2S) biogenesis in oil reservoirs is a primary cause of souring and of associated costs in reservoir and pipeline maintenance. In addition to the corrosive effects of the H2S itself, abiotic and biological oxidation also generates sulfuric acid, further degrading metallic surfaces. Amending these environments with perchlorate (ClO4-) resolves these problems by inhibition of biological sulfate reduction and re-oxidation of H2S to elemental sulfur by dissimilatory (per)chlorate reducing bacteria (DPRB). Triplicate flow through columns packed with San Francisco bay sediment were flushed with bay water ([SO4=] = 25-30 mM) containing yeast extract with 50 mM inhibitor concentrations (NO3-or ClO4-) decreasing to 25 mM and finally 12.5 mM. Influent and effluent geochemistry was monitored and DNA was prepared from the sediment bed for microbial community analysis. Souring was reversed by both treatments (at 50 mM) compared to the control columns that had no ion addition. Nitrate began to re-sour when treatment concentration was decreased to 25 mM but treatment had to be decreased to 12.5 mM before the perchlorate treated columns began to re-sour. However, the treated columns re-soured to a lesser extent than the control columns. Phylochip microbial community analyses indicated microbial community shifts and phylogenetic clustering by treatment. Isotopic analysis of sulfate showed trends that broadly agreed with the geochemistry but also suggested further sulfur cycling was occurring. This study indicates that perchlorate shows great promise as an inhibitor of sulfidogenesis in natural communities and provides insight into which organisms are involved in this process.

  8. Optimizing potentiometric ionophore and electrode design for environmental on-site control of antibiotic drugs: application to sulfamethoxazole. (United States)

    Almeida, S A A; Truta, Liliana A A N A; Queirós, Raquel B; Montenegro, M C B S M; Cunha, Alexandre L; Sales, M G F


    Potentiometric sensors are typically unable to carry out on-site monitoring of environmental drug contaminants because of their high limits of detection (LODs). Designing a novel ligand material for the target analyte and managing the composition of the internal reference solution have been the strategies employed here to produce for the first time a potentiometric-based direct reading method for an environmental drug contaminant. This concept has been applied to sulfamethoxazole (SMX), one of the many antibiotics used in aquaculture practices that may occur in environmental waters. The novel ligand has been produced by imprinting SMX on the surface of graphitic carbon nanostructures (CN)environmental water. The best membrane cocktail was applied on the smaller end of a 1000 μL micropipette tip made of polypropylene. The tip was then filled with inner reference solution containing SMX and chlorate (as interfering compound). The corresponding concentrations were studied for 1 × 10(-5) to 1 × 10(-10) and 1 × 10(-3) to 1 × 10(-8)mol/L. The best condition allowed the detection of 5.92 ng/L (or 2.3 × 10(-8)mol/L) SMX for a sub-Nernstian slope of -40.3 mV/decade from 5.0 × 10(-8) to 2.4 × 10(-5)mol/L. The described sensors were found promising devices for field applications. The good selectivity of the sensory materials together with a carefully selected composition for the inner reference solution allowed LODs near the nanomolar range. Both solid-contact and "pipette tip"-based sensors were successfully applied to the analysis of aquaculture waters.

  9. Silicic volcanism on Mars evidenced by tridymite in high-SiO2 sedimentary rock at Gale crater (United States)

    Morris, Richard V.; Vaniman, David T.; Blake, David F.; Gellert, Ralf; Chipera, Steve J.; Rampe, Elizabeth B.; Ming, Douglas W.; Morrison, Shaunna M.; Downs, Robert T.; Treiman, Allan H.; Yen, Albert S.; Grotzinger, John P.; Achilles, Cherie N.; Bristow, Thomas F.; Crisp, Joy A.; Des Marais, David J.; Farmer, Jack D.; Fendrich, Kim V.; Frydenvang, Jens; Graff, Trevor G.; Morookian, John-Michael; Stolper, Edward M.; Schwenzer, Susanne P.


    Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity. The tridymitic mudstone has ˜40 wt.% crystalline and ˜60 wt.% X-ray amorphous material and a bulk composition with ˜74 wt.% SiO2 (Alpha Particle X-Ray Spectrometer analysis). Plagioclase (˜17 wt.% of bulk sample), tridymite (˜14 wt.%), sanidine (˜3 wt.%), cation-deficient magnetite (˜3 wt.%), cristobalite (˜2 wt.%), and anhydrite (˜1 wt.%) are the mudstone crystalline minerals. Amorphous material is silica-rich (˜39 wt.% opal-A and/or high-SiO2 glass and opal-CT), volatile-bearing (16 wt.% mixed cation sulfates, phosphates, and chlorides-perchlorates-chlorates), and has minor TiO2 and Fe2O3T oxides (˜5 wt.%). Rietveld refinement yielded a monoclinic structural model for a well-crystalline tridymite, consistent with high formation temperatures. Terrestrial tridymite is commonly associated with silicic volcanism, and detritus from such volcanism in a “Lake Gale” catchment environment can account for Buckskin's tridymite, cristobalite, feldspar, and any residual high-SiO2 glass. These cogenetic detrital phases are possibly sourced from the Gale crater wall/rim/central peak. Opaline silica could form during diagenesis from high-SiO2 glass, as amorphous precipitated silica, or as a residue of acidic leaching in the sediment source region or at Marias Pass. The amorphous mixed-cation salts and oxides and possibly the crystalline magnetite (otherwise detrital) are primary precipitates and/or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions, temperatures, and acidities. Anhydrite is post lithification fracture/vein fill.

  10. Experimental research on the preparation of polyferric aluminum chloride by acid pickle and spent lye%以废酸、废碱液制备聚合氯化铁铝的实验研究

    Institute of Scientific and Technical Information of China (English)

    邵青; 霍文敏; 苑运丽; 王震


    以钢厂含铁废酸和铝加工业含铝废碱及废铁屑为原料制备聚合氯化铁铝(PFAC).实验研究了废铁屑加入量等因素对Fe2+溶出率的影响,同时研究了Fe2+的氧化条件.结果表明,在25℃、反应时间为15~20 min、氧化剂氯酸钠加入量等于化学计量值时,Fe2+氧化率可达98.7%以上.用废碱液调整盐基度,PFAC盐基度为20%时,对活性蓝P-3R水溶液的A590去除率可达99.8%;并对PFAC样品进行了红外光谱表征.%Iron-containing acid pickle in steel works,aluminum-containing spent lye in aluminum processing industry and waste iron scraps have been used as raw materials for preparing polyferric aluminum chloride (PFAC). The influence of waste iron scraps dosage and other factors on Fe2+ dissolution rate is studies. The oxidation rate of Fe2+ is 98.7%,when the oxidation conditions are as follows: its temperature is 25 ℃, reaction time 15-20 min,and the dosage of sodium chlorate equals to stoichiometric value. Spent lye is used for adjusting the PFAC basicity to 20%. The As90 removing rate of the activated Blue P-3R aqueous solution can reach 99.8%; and the PFAC samples are characterized by infrared spectroscopy.

  11. Properties of the periplasmic ModA molybdate-binding protein of Escherichia coli. (United States)

    Rech, S; Wolin, C; Gunsalus, R P


    The modABCD operon, located at 17 min on the Escherichia coli chromosome, encodes the protein components of a high affinity molybdate uptake system. Sequence analysis of the modA gene (GenBank L34009) predicts that it encodes a periplasmic binding protein based on the presence of a leader-like sequence at its N terminus. To examine the properties of the ModA protein, the modA structural gene was overexpressed, and its product was purified. The ModA protein was localized to the periplasmic space of the cell, and it was released following a gentle osmotic shock. The N-terminal sequence of ModA confirmed that a leader region of 24 amino acids was removed upon export from the cell. The apparent size of ModA is 31.6 kDa as determined by gel sieve chromatography, whereas it is 22.5 kDa when examined by SDS-polyacrylamide gel electrophoresis. A ligand-dependent protein mobility shift assay was devised using a native polyacrylamide gel electrophoresis protocol to examine binding of molybdate and other anions to the ModA periplasmic protein. Whereas molybdate and tungstate were bound with high affinity (approximately 5 microM), sulfate, chromate, selenate, phosphate, and chlorate did not bind even when tested at 2 mM. A UV spectral assay revealed apparent Kd values of binding for molybdate and tungstate of 3 and 7 microM, respectively. Strains defective in the modA gene were unable to transport molybdate unless high levels of the anion were supplied in the medium. Therefore the modA gene product is essential for high affinity molybdate uptake by the cell. Tungstate interference of molybdate acquisition by the cell is apparently due in part to the high affinity of the ModA protein for this anion.

  12. The relationship between anammox and denitrification in the sediment of an inland river

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Sheng, E-mail: [Eco-environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, No. 1000 Jinqi Road, Shanghai 201403 (China); Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan); Borjigin, Sodbilig; Riya, Shohei; Terada, Akihiko; Hosomi, Masaaki [Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)


    This study measured the microbial processes of anaerobic ammonium oxidation (anammox) and denitrification in sediment sampled from two sites in the estuary of an inland river (Koisegawa River, Ibaragi prefecture, Japan) using a nitrogen isotope pairing technique (IPT). The responses of anammox and denitrification activities to temperature and nitrate concentration were also evaluated. Further, to elucidate the correlation between anammox and denitrification processes, an inhibition experiment was conducted, using chlorate to inhibit the first step of denitrification. Denitrification activity was much higher than anammox activity, and it reached a maximum at the surface layer in February 2012. Denitrification activity decreased as sediment depth increased, and a similar phenomenon was observed for anammox activity in the sediment of site A, where aquatic plants were absent from the surroundings. The activities of both denitrification and anammox were temperature-dependent, but they responded differently to changes in incubation temperature. Compared to a linear increase in denitrification as temperature rose to 35 °C, the optimal temperature for anammox was 25 °C, after which the activity decreased sharply. At the same time, both anammox and denitrification activities increased with NO{sub 3}{sup −} concentration. The Michaelis–Menten kinetic constants (V{sub max} and K{sub m}) of denitrification were significantly higher than those of the anammox process. Furthermore, anammox activity decreased accordingly when the first step of denitrification was inhibited, which probably reduced the amount of the intermediate NO{sub 2}{sup −}. Our study provides the first direct exploration of the denitrification-dependent correlation of anammox activity in the sediment of inland river. - Highlights: • The activity of denitrification in river sediment was much higher than anammox. • Denitrification and anammox respond differently to changes in temperature.

  13. Kinetics of nitrate and perchlorate removal and biofilm stratification in an ion exchange membrane bioreactor. (United States)

    Ricardo, Ana R; Carvalho, Gilda; Velizarov, Svetlozar; Crespo, João G; Reis, Maria A M


    The biological degradation of nitrate and perchlorate was investigated in an ion exchange membrane bioreactor (IEMB) using a mixed anoxic microbial culture and ethanol as the carbon source. In this process, a membrane-supported biofilm reduces nitrate and perchlorate delivered through an anion exchange membrane from a polluted water stream, containing 60 mg/L of NO₃⁻ and 100 μg/L of ClO₄⁻. Under ammonia limiting conditions, the perchlorate reduction rate decreased by 10%, whereas the nitrate reduction rate was unaffected. Though nitrate and perchlorate accumulated in the bioreactor, their concentrations in the treated water (2.8 ± 0.5 mg/L of NO₃⁻ and 7.0 ± 0.8 μg/L of ClO₄⁻, respectively) were always below the drinking water regulatory levels, due to Donnan dialysis control of the ionic transport in the system. Kinetic parameters determined for the mixed microbial culture in suspension showed that the nitrate reduction rate was 35 times higher than the maximum perchlorate reduction rate. It was found that perchlorate reduction was inhibited by nitrate, since after nitrate depletion perchlorate reduction rate increased by 77%. The biofilm developed in the IEMB was cryosectioned and the microbial population was analyzed by fluorescence in situ hybridization (FISH). The results obtained seem to indicate that the kinetic advantage of nitrate reduction favored accumulation of denitrifiers near the membrane, whereas per(chlorate) reducing bacteria were mainly positioned at the biofilm outer surface, contacting the biomedium. As a consequence of the biofilm stratification, the reduction of perchlorate and nitrate occur sequentially in space allowing for the removal of both ions in the IEMB.

  14. Functional assessment of the Medicago truncatula NIP/LATD protein demonstrates that it is a high-affinity nitrate transporter. (United States)

    Bagchi, Rammyani; Salehin, Mohammad; Adeyemo, O Sarah; Salazar, Carolina; Shulaev, Vladimir; Sherrier, D Janine; Dickstein, Rebecca


    The Medicago truncatula NIP/LATD (for Numerous Infections and Polyphenolics/Lateral root-organ Defective) gene encodes a protein found in a clade of nitrate transporters within the large NRT1(PTR) family that also encodes transporters of dipeptides and tripeptides, dicarboxylates, auxin, and abscisic acid. Of the NRT1(PTR) members known to transport nitrate, most are low-affinity transporters. Here, we show that M. truncatula nip/latd mutants are more defective in their lateral root responses to nitrate provided at low (250 μm) concentrations than at higher (5 mm) concentrations; however, nitrate uptake experiments showed no discernible differences in uptake in the mutants. Heterologous expression experiments showed that MtNIP/LATD encodes a nitrate transporter: expression in Xenopus laevis oocytes conferred upon the oocytes the ability to take up nitrate from the medium with high affinity, and expression of MtNIP/LATD in an Arabidopsis chl1(nrt1.1) mutant rescued the chlorate susceptibility phenotype. X. laevis oocytes expressing mutant Mtnip-1 and Mtlatd were unable to take up nitrate from the medium, but oocytes expressing the less severe Mtnip-3 allele were proficient in nitrate transport. M. truncatula nip/latd mutants have pleiotropic defects in nodulation and root architecture. Expression of the Arabidopsis NRT1.1 gene in mutant Mtnip-1 roots partially rescued Mtnip-1 for root architecture defects but not for nodulation defects. This suggests that the spectrum of activities inherent in AtNRT1.1 is different from that possessed by MtNIP/LATD, but it could also reflect stability differences of each protein in M. truncatula. Collectively, the data show that MtNIP/LATD is a high-affinity nitrate transporter and suggest that it could have another function.

  15. Methane oxidation linked to chlorite dismutation (United States)

    Miller, Laurence G.; Baesman, Shaun M.; Carlström, Charlotte I.; Coates, John D.; Oremland, Ronald S.


    We examined the potential for CH4 oxidation to be coupled with oxygen derived from the dissimilatory reduction of perchlorate, chlorate, or via chlorite (ClO−2) dismutation. Although dissimilatory reduction of ClO−4 and ClO−3 could be inferred from the accumulation of chloride ions either in spent media or in soil slurries prepared from exposed freshwater lake sediment, neither of these oxyanions evoked methane oxidation when added to either anaerobic mixed cultures or soil enriched in methanotrophs. In contrast, ClO−2 amendment elicited such activity. Methane (0.2 kPa) was completely removed within several days from the headspace of cell suspensions of Dechloromonas agitata CKB incubated with either Methylococcus capsulatus Bath or Methylomicrobium album BG8 in the presence of 5 mM ClO−2. We also observed complete removal of 0.2 kPa CH4 in bottles containing soil enriched in methanotrophs when co-incubated with D. agitata CKB and 10 mM ClO−2. However, to be effective these experiments required physical separation of soil from D. agitata CKB to allow for the partitioning of O2 liberated from chlorite dismutation into the shared headspace. Although a link between ClO−2 and CH4 consumption was established in soils and cultures, no upstream connection with either ClO−4 or ClO−3 was discerned. This result suggests that the release of O2 during enzymatic perchlorate reduction was negligible, and that the oxygen produced was unavailable to the aerobic methanotrophs.

  16. Processing of Gold-containing Slag from Sulfuric Acid Production Using Sulfatizing Roasting Followed by Chlorine Leaching%含金硫酸渣硫酸盐化焙烧-氯化浸金研究

    Institute of Scientific and Technical Information of China (English)

    尤大海; 张亚辉; 隆岗; 涂博; 黄俊玮


    针对难处理含金硫酸渣进行了硫酸盐化焙烧-氯化(氯酸钠-氯盐)浸出试验研究,考察了氯酸钠用量、氯化钠用量、液固比、浸出时间、浸出温度、焙烧预处理等因素对金浸出率的影响。研究结果表明,在优化的试验条件:氯化钠用量为80 kg/t,氯酸钠100 kg/t,反应温度80℃,液固比为3,反应时间为4 h下,处理该含金硫酸渣可以得到91.44%的金浸出率。%Sulfatizing roasting and chlorine leaching of refractory gold-containing slag from sulfuric acid production have been investigated. The effects of sodium chlorate dosage, sodium chloride dosage, liquid-solid ratio, leaching time, reaction temperature and pretreatment condition on leaching recovery of gold have been studied. The results show that the leaching rate can reach as high as 91.44% under the optimum conditions that the addition of NaClO3 is 100 kg/t, the addition of NaCl is 80 kg/t, the liquid-solid ratio is 3, the leaching temperature is 80℃ and the leaching time is 4.0 h.

  17. Application and Research on Polyaluminum Chloride in Water Treatment of Power Plant%聚合铝在发电厂水处理中的应用与研究

    Institute of Scientific and Technical Information of China (English)



    Polyaluminum chloride is widely used for water treatment in power plant. To find out the best service condition, pH value, temperature and dosage of raw water are changed. By measuring residual turbidity of wa-ter samples and UV254, coagulation effect is determined. The test shows that when pH value is 6 coagulation effect becomes optimal, he most appropriate dosage of polyaluminum chloride is 9 mg/L-1 and the most suitable water temperature for polyaluminum chloride coagulation is about 25 Celsius degrees. Compared with crys-talline aluminum chlorate, polyaluminum chloride coagulant is more effective and less dose-consuming.%聚合铝在发电厂水处理中的应用广泛。为寻找聚合铝的最佳使用条件,通过改变原水的pH值、温度及聚合铝的用量等来确定聚合铝使用的最佳条件,通过测量水样的剩余浊度和UV254确定混凝效果。试验表明:聚合铝在pH值为6左右时混凝效果最好且此时聚合铝的最佳投药量为9 mg•L-1左右,聚合铝混凝的最佳水温在25℃左右;聚合铝混凝剂与结晶氯化铝相比混凝效果更高,而且投药量更少。

  18. Effects of Different Oxidants on HCl-based Pickling Process of 430 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Qiong XIE; Pei-yang SHI; Cheng-jun LIU; Mao-fa JIANG


    To shorten the time required for the pickling process and to enhance the quality of ferritic stainless steel plates,the effects of oxidants including hydrogen peroxide (H2 O2 ),potassium permanganate (KMnO4 ),and potas-sium chlorate (KClO3 )on the pickling behavior in HCl-based electrolyte as well as the surface quality of hot-rolled and blasted 430 stainless steel (430-SS)were studied.Experiments were conducted using mass-loss tests,micro-structure analyses,potentiodynamic polarization curves,and electrochemical impedance spectroscopy measurements. The results showed that the addition of oxidants substantially accelerated the pickling process of 430-SS by enhancing the cathodic reaction rate and reducing the charge transfer resistance.In electrolytes comprising 5-8 mass% HCl at a temperature of 40-60 ℃ and at the same concentration within the range from 0 to 2 mass%,H2 O2 was demon-strated to be superior to KMnO4 and KClO3 in accelerating the pickling process.The surface quality of 430-SS pick-led in the presence of H2 O2 was better than those of specimens pickled in the presence of KMnO4 and KClO3 when the removal of the oxide layer,intergranular corrosion,and surface roughness were collectively considered. When 1 mass% H2 O2 was added,the mass loss rate of 430-SS was increased by 629% and no residual oxide layer or intergranular corrosion was observed on the surface of the steel;in addition,the roughness was only 1.7μm.H2 O2 was determined to be a better oxidant than KMnO4 and KClO3 when the pickling process,surface quality,solution recycling,and environment protection were considered as a whole.

  19. Children at health risks. (United States)

    Sekar, H R


    In India, 69% of the children of the working class die, most of whom are child laborers. Economic pressure forces parents to make their children work. Employers want child workers because they can manipulate them and pay them low wages, thereby ensuring their viability. The caste system induces social inequality, inheritance invokes cultural inequality, and patriarchal socialization is responsible for gender inequality, all of which perpetuates exploitation of children by employers. In Sivakasi, an estimated 125,000 children make up the child labor force, comprising 30% of the entire labor force. 75% are from the lowest castes. 90% of child workers are girls because they are more obedient and accept even lower wages than boys, and girls need to save for their dowry. Girls often suffer verbal and physical abuse. Like their parents who were also child workers, child workers are illiterate and work long hours. A small rich elite in Sivakasi controls most of the trading and industrial capital, educational institutions, and voluntary organizations. Employers' agents give parents a loan and use their children's labor as security. Each day, they bring child workers to Sivakasi in factory buses from villages to work at least 12 hour days. They work under hazardous conditions, e.g., working with toxic chemicals. Coughing, sore throat, dizziness, methemoglobinemia, and anemia are common effects of ingestion or inhalation of chlorate dust. Inhalation of sulphur dust causes respiratory infections, eye infections, and chronic lung diseases (e.g., asthma). Fires and explosions are common risks for working children. Factory management seldom undertake fire prevention measures. An extensive survey of the problem of child labor is needed in Sivakasi before systematic planning to protect children could be done. Overall development, especially agricultural development, is needed. Parents, employers, enforcement authorities, trade unions, and social groups need to be sensitized to the

  20. Kinetics and mechanism of styrene epoxidation by chlorite: role of chlorine dioxide. (United States)

    Leigh, Jessica K; Rajput, Jonathan; Richardson, David E


    An investigation of the kinetics and mechanism for epoxidation of styrene and para-substituted styrenes by chlorite at 25 °C in the pH range of 5-6 is described. The proposed mechanism in water and water/acetonitrile includes seven oxidation states of chlorine (-I, 0, I, II, III, IV, and V) to account for the observed kinetics and product distributions. The model provides an unusually detailed quantitative mechanism for the complex reactions that occur in mixtures of chlorine species and organic substrates, particularly when the strong oxidant chlorite is employed. Kinetic control of the reaction is achieved by the addition of chlorine dioxide to the reaction mixture, thereby eliminating a substantial induction period observed when chlorite is used alone. The epoxidation agent is identified as chlorine dioxide, which is continually formed by the reaction of chlorite with hypochlorous acid that results from ClO produced by the epoxidation reaction. The overall stoichiometry is the result of two competing chain reactions in which the reactive intermediate ClO reacts with either chlorine dioxide or chlorite ion to produce hypochlorous acid and chlorate or chloride, respectively. At high chlorite ion concentrations, HOCl is rapidly eliminated by reaction with chlorite, minimizing side reactions between HOCl and Cl2 with the starting material. Epoxide selectivity (>90% under optimal conditions) is accurately predicted by the kinetic model. The model rate constant for direct reaction of styrene with ClO2(aq) to produce epoxide is (1.16 ± 0.07) × 10(-2) M(-1) s(-1) for 60:40 water/acetonitrile with 0.20 M acetate buffer. Rate constants for para substituted styrenes (R = -SO3(-), -OMe, -Me, -Cl, -H, and -NO2) with ClO2 were determined. The results support the radical addition/elimination mechanism originally proposed by Kolar and Lindgren to account for the formation of styrene oxide in the reaction of styrene with chlorine dioxide.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  2. Preliminary studies on the Marcoule site, using a wind-tunnel; Etude preliminaire en soufflerie du site de Marcoule

    Energy Technology Data Exchange (ETDEWEB)

    Chassany, J.Ph. [Commissariat a l' Energie Atomique, Service de Protection contre les Radiations, Marcoule (France). Centre d' Etudes Nucleaires; Parigi, H. [Institut de Mecanique des Fluides, 13 - Marseille (France); Salaun-Penquer, G. [Centre National de la Recherche Scientifique (CNRS), 13 - Marseille (France)


    The tests were carried out in the 3.30 x 2.20 subsonic elliptical wind-tunnel of the Marseille Institute of fluid mechanics, on a 1/1000 scale model measuring 3 m x 3 m. The aerodynamic field developing above the site, made visible by ammonium, hydro-chlorate fumes, and the residues were observed and filmed by means of a synchronised cine-camera with stroboscopic lighting for 4 wind directions. The fall-out from the various waste products was obtained from a spraying of lead acetate solution on the model and hydrogen sulphide emissions. The zones of maximum pollution can be determined from a study of the film taken during the blackening of the spots. (author) [French] Les essais ont ete effectues dans la soufflerie elliptique subsonique de 3,30 x 2,20 de l'Institut de Mecanique des fluides de Marseille, sur une maquette, a l'echelle 1/1000, de 3 m x 3 m. Le champ aerodynamique se developpant au-dessus du Site, visualise par des fumees de chlorydrate d'ammoniaque ainsi que les rejets ont ete observes et filmes avec une camera synchronisee avec un eclairage stroboscopique pour 4 directions du vent. Les retombees au sol provenant des differents rejets ont ete obtenues a partir de la pulverisation d'une solution d'acetate de plomb sur la maquette et d'emissions de sulfure d'hydrogene. L'etude du film pris au cours du noircissement des taches permet de determiner les zones de pollution maximales. (auteur)

  3. Application of electrochemical advanced oxidation processes to the mineralization of the herbicide diuron. (United States)

    Pipi, Angelo R F; Sirés, Ignasi; De Andrade, Adalgisa R; Brillas, Enric


    Here, solutions with 0.185mM of the herbicide diuron of pH 3.0 have been treated by electrochemical advanced oxidation processes (EAOPs) like electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) or solar PEF (SPEF). Trials were performed in stirred tank reactors of 100mL and in a recirculation flow plant of 2.5L using a filter-press reactor with a Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 electrogeneration. Oxidant hydroxyl radicals were formed from water oxidation at the anode and/or in the bulk from Fenton's reaction between added Fe(2+) and generated H2O2. In both systems, the relative oxidation ability of the EAOPs increased in the sequence EO-H2O2chlorate and perchlorate ions at the BDD surface.

  4. Characterization of a hybrid-smectite nanomaterial formed by immobilizing of N-pyridin-2-ylmethylsuccinamic acid onto (3-aminopropyl)triethoxysilane modified smectite and its potentiometric sensor application (United States)

    Topcu, Cihan; Caglar, Sema; Caglar, Bulent; Coldur, Fatih; Cubuk, Osman; Sarp, Gokhan; Gedik, Kubra; Bozkurt Cirak, Burcu; Tabak, Ahmet


    A novel N-pyridin-2-ylmethylsuccinamic acid-functionalized smectite nanomaterial was synthesized by immobilizing of N-pyridin-2-ylmethylsuccinamic acid through chemical bonding onto (3-aminopropyl)triethoxysilane modified smectite. The structural, thermal, morphological and surface properties of raw, silane-grafted and the N-pyridin-2-ylmethylsuccinamic acid-functionalized smectites were investigated by various characterization techniques. The thermal analysis data showed the presence of peaks in the temperature range from 200 °C to 600 °C due to the presence of physically adsorbed silanes, intercalated silanes, surface grafted silanes and chemically grafted silane molecules between the smectite layers. The powder x-ray diffraction patterns clearly indicated that the aminopropyl molecules also intercalated into the smectite interlayers as bilayer arrangement whereas N-pyridin-2-ylmethylsuccinamic acid molecules were only attached to 3-aminopropyltriethoxysilane molecules on the external surface and edges of clay and they did not intercalate. Fourier transform infrared spectroscopy confirms N-pyridin-2-ylmethylsuccinamic acid molecules bonding through the amide bond between the amine group of aminopropyltriethoxysilane molecules and a carboxylic acid functional group of N-pyridin-2-ylmethylsuccinamic acid molecules. The guest molecules functionalized onto the smectite caused significant alterations in the textural and morphological parameters of the raw smectite. The anchoring of N-pyridin-2-ylmethylsuccinamic acid molecules led to positive electrophoretic mobility values when compared to starting materials. N-pyridin-2-ylmethylsuccinamic acid-functionalized smectite was employed as an electroactive ingredient in the structure of potentiometric PVC-membrane sensor. The sensor exhibited more selective potentiometric response towards chlorate ions compared to the other common anionic species.

  5. Silicic volcanism on Mars evidenced by tridymite in high-SiO2 sedimentary rock at Gale crater. (United States)

    Morris, Richard V; Vaniman, David T; Blake, David F; Gellert, Ralf; Chipera, Steve J; Rampe, Elizabeth B; Ming, Douglas W; Morrison, Shaunna M; Downs, Robert T; Treiman, Allan H; Yen, Albert S; Grotzinger, John P; Achilles, Cherie N; Bristow, Thomas F; Crisp, Joy A; Des Marais, David J; Farmer, Jack D; Fendrich, Kim V; Frydenvang, Jens; Graff, Trevor G; Morookian, John-Michael; Stolper, Edward M; Schwenzer, Susanne P


    Tridymite, a low-pressure, high-temperature (>870 °C) SiO2 polymorph, was detected in a drill sample of laminated mudstone (Buckskin) at Marias Pass in Gale crater, Mars, by the Chemistry and Mineralogy X-ray diffraction instrument onboard the Mars Science Laboratory rover Curiosity The tridymitic mudstone has ∼40 wt.% crystalline and ∼60 wt.% X-ray amorphous material and a bulk composition with ∼74 wt.% SiO2 (Alpha Particle X-Ray Spectrometer analysis). Plagioclase (∼17 wt.% of bulk sample), tridymite (∼14 wt.%), sanidine (∼3 wt.%), cation-deficient magnetite (∼3 wt.%), cristobalite (∼2 wt.%), and anhydrite (∼1 wt.%) are the mudstone crystalline minerals. Amorphous material is silica-rich (∼39 wt.% opal-A and/or high-SiO2 glass and opal-CT), volatile-bearing (16 wt.% mixed cation sulfates, phosphates, and chlorides-perchlorates-chlorates), and has minor TiO2 and Fe2O3T oxides (∼5 wt.%). Rietveld refinement yielded a monoclinic structural model for a well-crystalline tridymite, consistent with high formation temperatures. Terrestrial tridymite is commonly associated with silicic volcanism, and detritus from such volcanism in a "Lake Gale" catchment environment can account for Buckskin's tridymite, cristobalite, feldspar, and any residual high-SiO2 glass. These cogenetic detrital phases are possibly sourced from the Gale crater wall/rim/central peak. Opaline silica could form during diagenesis from high-SiO2 glass, as amorphous precipitated silica, or as a residue of acidic leaching in the sediment source region or at Marias Pass. The amorphous mixed-cation salts and oxides and possibly the crystalline magnetite (otherwise detrital) are primary precipitates and/or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions, temperatures, and acidities. Anhydrite is post lithification fracture/vein fill.

  6. Effect of evaporation and freezing on the salt paragenesis and habitability of brines at the Phoenix landing site (United States)

    Elsenousy, Amira; Hanley, Jennifer; Chevrier, Vincent F.


    The WCL (Wet Chemistry Lab) instrument on board the Phoenix Lander identified the soluble ionic composition of the soil at the landing site. However, few studies have been conducted to understand the parent salts of these soluble ions. Here we studied the possible salt assemblages at the Phoenix landing site using two different thermodynamic models: FREZCHEM and Geochemist's Workbench (GWB). Two precipitation pathways were used: evaporation (T > 0 °C using both FREZCHEM and GWB) and freezing (T evaporation-showed some common minerals that precipitated regardless of the ionic initial concentration. These ubiquitous minerals are magnesium chlorate hexahydrate Mg(ClO3)2ṡ6H2O, potassium perchlorate (KClO4) and gypsum (CaSO4ṡ2H2O). Other minerals evidence specific precipitation pathway. Precipitation of highly hydrated salts such as meridianiite (MgSO4ṡ11H2O) and MgCl2ṡ12H2O indicate freezing pathway, while precipitation of the low hydrated salts (anhydrite, kieserite and epsomite) indicate evaporation. The present hydration states of the precipitated hydrated minerals probably reflect the ongoing thermal processing and recent seasonally varying humidity conditions at the landing site, but these hydration states might not reflect the original depositional conditions. The simulations also showed the absence of Ca-perchlorate in all models, mainly because of the formation of two main salts: KClO4 and gypsum which are major sinks for ClO-4 and Ca2+ respectively. Finally, in consideration to the Martian life, it might survive at the very low temperatures and low water activities of the liquids formed. However, besides the big and widely recognized challenges to life posed by those extreme environmental parameters (especially low water activity), another main challenge for any form of life in such an environment is to maintain contact with the small droplets of the stable liquids in the regolith and to interact with life in other isolated droplets.

  7. 铅阳极泥中有价金属的分离研究%Research on Separation of Valued Metals from Lead Anode Slime

    Institute of Scientific and Technical Information of China (English)

    吴文花; 刘吉波; 王志坚; 苏正夫


    After natural stacking oxidation,lead anode slime was leached with potential controlled at 80 ℃ for four hours in medium of 5 mol/L sulfuric acid added with sodium chloride (c(Cl-) =3 mol/L) and oxidant of sodium chlorate with ratio of solid to liquid of 5 ∶ 1.The results show that the leaching rates of copper,bismuth,antimony and arsenic are all above 99%,the leaching rate of tellurium is above 97%,and the leaching rates of gold and silver are below 1% under the potential controlled leaching conditions including stacking duration of lead anode slime of over 4 days,oxidant dosage of >20%,and potential of 40~500 mV.Copper,bismuth,antimony,arsenic and tellurium are successfully separated from gold and silver.%铅阳极泥经过自然堆放氧化后,在5 mol/L硫酸介质中加入一定量的氯化钠(c(Cl-)=3 mol/L)和氧化剂氯酸钠,液固比为5∶1,80℃控制电位氧化浸出4h.结果表明,当铅阳极泥堆放氧化4天以上,氧化剂用量大于20%,电位400~500 mV时,铜、铋、锑、砷的浸出率均在99%以上,碲浸出率大于97%,金、银入液损失均小于1%,很好地实现了铜、铋、锑、砷、碲与金、银的分离.

  8. Chlorine and Sulfur Volatiles from in Situ Measurements of Martian Surface Materials (United States)

    Clark, B. C.


    A sentinel discovery by the first in situ measurements on Mars was the high sulfur and chlorine content of global-wide soils. A variety of circumstantial evidence led to the conclusion that soil S is in the form of sulfate, and the Cl is probably chloride. An early hypothesis states that these volatiles are emitted as gases from magmas, and quickly react with dust, soil, and exposed rocks. Subsequent determination that SNC meteorites are also samples of the martian crust revealed a significantly higher S content, as sulfide, than terrestrial igneous rocks but substantially less than in soils. The ensuing wet chemical analyses by the high-latitude Phoenix mission discovered not only chloride but also perchlorate and possibly chlorate. MSL data now also implicate perchlorate at low latitudes. Gaseous interactions may have produced amorphous material on grain surfaces without forming stoichiometric salts. Yet, when exposed to liquid water, Phoenix samples released electrolytes, indicating that the soils have not been leached by rain or fresh groundwater. Sulfate occurrences at many locations on Mars, as well as some chloride enrichments, have now been discovered by remote sensing, Landed missions have discovered Cl-enrichments and ferric, Mg, Ca and more complex sulfates as duricrust, subsurface soil horizons, sandstone evaporites, and rock coatings - most of which cannot be detected from orbit. Salt-forming volatiles affect habitability wherever they are in physical contact: physicochemical parameters (ionic strength, freezing point, water activity); S is an essential element for terrestrial organisms; perchlorate is an oxidant which can degrade some organics but also can be utilized as an energy source; the entire valence range of S-compounds has been exploited by diverse microbiota on Earth. Whether such salt-induced conditions are "extremes" of habitability depends on the relative abundance of liquid H2O.

  9. Syndecan 4 interacts genetically with Vangl2 to regulate neural tube closure and planar cell polarity. (United States)

    Escobedo, Noelia; Contreras, Osvaldo; Muñoz, Rosana; Farías, Marjorie; Carrasco, Héctor; Hill, Charlotte; Tran, Uyen; Pryor, Sophie E; Wessely, Oliver; Copp, Andrew J; Larraín, Juan


    Syndecan 4 (Sdc4) is a cell-surface heparan sulfate proteoglycan (HSPG) that regulates gastrulation, neural tube closure and directed neural crest migration in Xenopus development. To determine whether Sdc4 participates in Wnt/PCP signaling during mouse development, we evaluated a possible interaction between a null mutation of Sdc4 and the loop-tail allele of Vangl2. Sdc4 is expressed in multiple tissues, but particularly in the non-neural ectoderm, hindgut and otic vesicles. Sdc4;Vangl2(Lp) compound mutant mice have defective spinal neural tube closure, disrupted orientation of the stereocilia bundles in the cochlea and delayed wound healing, demonstrating a strong genetic interaction. In Xenopus, co-injection of suboptimal amounts of Sdc4 and Vangl2 morpholinos resulted in a significantly greater proportion of embryos with defective neural tube closure than each individual morpholino alone. To probe the mechanism of this interaction, we overexpressed or knocked down Vangl2 function in HEK293 cells. The Sdc4 and Vangl2 proteins colocalize, and Vangl2, particularly the Vangl2(Lp) mutant form, diminishes Sdc4 protein levels. Conversely, Vangl2 knockdown enhances Sdc4 protein levels. Overall HSPG steady-state levels were regulated by Vangl2, suggesting a molecular mechanism for the genetic interaction in which Vangl2(Lp/+) enhances the Sdc4-null phenotype. This could be mediated via heparan sulfate residues, as Vangl2(Lp/+) embryos fail to initiate neural tube closure and develop craniorachischisis (usually seen only in Vangl2(Lp/Lp)) when cultured in the presence of chlorate, a sulfation inhibitor. These results demonstrate that Sdc4 can participate in the Wnt/PCP pathway, unveiling its importance during neural tube closure in mammalian embryos.

  10. Perchlorate and volatiles of the brine of Lake Vida (Antarctica): Implication for the in situ analysis of Mars sediments (United States)

    Kenig, Fabien; Chou, Luoth; McKay, Christopher P.; Jackson, W. Andrew; Doran, Peter T.; Murray, Alison E.; Fritsen, Christian H.


    The cold (-13.4°C), cryoencapsulated, anoxic, interstitial brine of the >27 m thick ice of Lake Vida (Victoria Valley, Antarctica) contains 49 µg · L-1 of perchlorate and 11 µg · L-1 of chlorate. Lake Vida brine (LVBr) may provide an analog for potential oxychlorine-rich subsurface brine on Mars. LVBr volatiles were analyzed by solid-phase microextraction (SPME) gas chromatography-mass spectrometry (GC-MS) with two different SPME fibers. With the exception of volatile organic sulfur compounds, most other volatiles observed were artifacts produced in the GC injector when the thermal decomposition products of oxychlorines reacted with reduced carbon derived from LVBr and the SPME fiber phases. Analysis of MilliQ water with perchlorate (40 µg · L-1) showed low level of organic artifacts, reflecting carbon limitation. In order to observe sample-derived organic compounds, both in analog samples and on Mars, the molar abundance of reduced carbon in a sample must exceed those of O2 and Cl2 produced during decomposition of oxychlorines. This suggests that the abundance of compounds observed by the Sample Analysis at Mars (SAM) instruments in Sheepbed samples (CB-3, CB5, and CB6) may be controlled by an increase in the reduced-carbon/oxychlorine ratio of these samples. To increase chances of in situ detection of Martian organics during pyrolysis-GC-MS, we propose that the derivatization agents stored on SAM may be used as an external source of reduced carbon, increasing artificially the reduced-carbon to perchlorate ratio during pyrolysis, allowing the expression of more abundant and perhaps more diverse Martian organic matter.

  11. Identification and determination of inorganic anions in real extracts from pre- and post-blast residues by capillary electrophoresis. (United States)

    Sarazin, Cédric; Delaunay, Nathalie; Varenne, Anne; Vial, Jérôme; Costanza, Christine; Eudes, Véronique; Minet, Jean-Jacques; Gareil, Pierre


    Fast, selective, and sensitive analysis of inorganic anions is compulsory for the identification of explosives in post-blast or environmental samples. For the last twenty years, capillary electrophoresis (CE) has become a valuable alternative to ion chromatography (IC) for the analysis of inorganic-based explosives because of its low running costs and its simplicity of use. This article focuses on the development and validation of a CE method for the simultaneous analysis of 10 anions (chloride, nitrite, nitrate, thiosulphate, perchlorate, chlorate, thiocyanate, carbonate, sulphate, and phosphate) which can be found in post-blast residues, plus for the first time azide anion, possibly present in the composition of detonators, and the internal standard (formate) in 20 min total runtime. Intermediate precisions were 2.11% for normalized areas and 0.72% for normalized migration times. Limits of detection close to 0.5 ppm for all anions were obtained with the use of preconcentration techniques, thanks to a fast and simple sample preparation allowing the analysis of a large variety of matrices with the developed generic CE method. The matrix effects were statistically studied for the first time in the explosive field for different matrices, containing interfering anions and cations, sometimes at high levels. In fact, no significant matrix effect occurred (tests with blank matrix extracts of soil, cloth, glass, plastic, paper, cotton, and metal). Finally, analyses of real post-blast residues and real detonator extracts were performed. The CE results were compared with those obtained with the IC method used routinely and showed excellent correlation.

  12. Molecular analysis of microbial community in a groundwater sample polluted by landfill leachate and seawater

    Institute of Scientific and Technical Information of China (English)

    TIAN Yang-jie; YANG Hong; WU Xiu-juan; LI Dao-tang


    Seashore landfill aquifers are environments of special physicochemical conditions (high organic load and high salinity), and microbes in leachate-polluted aquifers play a significant role for intrinsic bioremediation. In order to characterize microbial diversity and look for clues on the relationship between microbial community structure and hydrochemistry, a culture-independent examination of a typical groundwater sample obtained from a seashore landfill was conducted by sequence analysis of 16S rDNA clone library. Two sets of universal 16S rDNA primers were used to amplify DNA extracted from the groundwater so that problems arising from primer efficiency and specificity could be reduced. Of 74 clones randomly selected from the libraries, 30 contained unique sequences whose analysis showed that the majority of them belonged to bacteria (95.9%), with Proteobacteria (63.5%) being the dominant division. One archaeal sequence and one eukaryotic sequence were found as well. Bacterial sequences belonging to the following phylogenic groups were identified: Bacteroidetes (20.3%), β, γ, δ and ε-subdivisions of Proteobacteria (47.3%, 9.5%, 5.4% and 1.3%, respectively), Firmicutes (1.4%), Actinobacteria (2.7%), Cyanobacteria (2.7%). The percentages of Proteobacteria and Bacteroides in seawater were greater than those in the groundwater from a non-seashore landfill, indicating a possible influence of seawater. Quite a few sequences had close relatives in marine or hypersaline environments. Many sequences showed affiliations with microbes involved in anaerobic fermentation. The remarkable abundance of sequences related to (per)chlorate-reducing bacteria (C1RB) in the groundwater was significant and worthy of further study.

  13. Manitoba's continuing drive to hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, R.V.; Crone, J. [Government of Manitoba, Winnipeg, MB (Canada). Manitoba Energy Development Initiative, Dept. of Science, Technology, Energy and Mines


    In 2001, the Government of Manitoba initiated a strategy to pursue hydrogen as a longer-term option within its portfolio of renewable energy opportunities. A key potential hydrogen application includes all-electric vehicles; metal air cells; and biofuels. A detailed hydrogen economic development strategy was formulated for the province as a whole. In 2003, Manitoba's Hydrogen Steering Committee released the first strategy document on hydrogen prepared by any jurisdiction in Canada. The report outlined an assessment framework using broad-based working groups to cover 5 lead areas. The report listed 5 priority actions on hydrogen, to which a sixth priority action has now been added. These include hydrogen buses and refueling; a by-product hydrogen fuel cell demonstration project; the creation of the Hydrogen Centre of Expertise Inc.; an on-site hydrogen system at Manitoba Hydro's Dorsey Station; a memorandum of understanding on hydrogen development with Iceland; and, a permanent refueling station and associated support facilities. These priority actions were undertaken to help define future directions and to gain experience in opportunity areas. Since the report's release, substantial progress has been made on all 6 priority actions. Two major hydrogen bus and refueling demonstration projects have been completed, with the most recent involving the hybrid fuel cell bus. Manitoba currently has 2 major sodium chlorate plants producing significant quantities of hydrogen as a by-product. This paper provided an update on the strategic approach taken by Manitoba and discussed how hydrogen can be integrated with other renewable energy priorities. 10 refs., 1 tab., 10 figs.

  14. Perchlorate and Volatiles of the Brine of Lake Vida (Antarctica): Implication for the in Situ Analysis of Mars Sediments (United States)

    Kenig, Fabien; Chou, Luoth; McKay, Christopher P.; Jackson, W. Andrew; Doran, Peter T.; Murray, Alison E.; Fritsen, Christian H.


    The cold (-13.4 C), cryoencapsulated, anoxic, interstitial brine of the 27 m-thick ice of Lake Vida (Victoria Valley, Antarctica) contains 49 microgram L-1 of perchlorate and 11 microgram L-1 of chlorate. Lake Vida brine (LVBr) may provide an analog for potential oxychlorine-rich subsurface brine on Mars. LVBr volatiles were analyzed by solid-phase microextraction (SPME) gas chromatography-mass spectrometry (GC-MS) with two different SPME fibers. With the exception of volatile organic sulfur compounds, most other volatiles observed were artifacts produced in the GC injector when the thermal decomposition products of oxychlorines reacted with reduced carbon derived from LVBr and the SPME fiber phases. Analysis of MilliQ water with perchlorate (40 microgram L-1) showed low level of organic artifacts, reflecting carbon limitation. In order to observe sample-derived organic compounds, both in analog samples and on Mars, the molar abundance of reduced carbon in a sample must exceed those of O2 and Cl2 produced during decomposition of oxychlorines. This suggests that the abundance of compounds observed by the Sample Analysis at Mars (SAM) instruments in Sheepbed samples (CB-3, CB5, and CB6) may be controlled by an increase in the reduced-carbon/oxychlorine ratio of these samples. To increase chances of in situ detection of Martian organics during pyrolysis-GC-MS, we propose that the derivatization agents stored on SAM may be used as an external source of reduced carbon, increasing artificially the reduced-carbon to perchlorate ratio during pyrolysis, allowing the expression of more abundant and perhaps more diverse Martian organic matter.

  15. Temporal changes in abundance and composition of ammonia-oxidizing bacterial and archaeal communities in a drained peat soil in relation to N{sub 2}O emissions

    Energy Technology Data Exchange (ETDEWEB)

    Andert, Janet [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Microbiology; Max-Planck-Institute of Colloids and Interfaces, Potsdam (Germany); Wessen, Ella; Hallin, Sara [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Microbiology; Boerjesson, Gunnar [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil and Environment


    Boreal peat soils comprise about 3% of the terrestrial environments, and when drained, they become sources of the greenhouse gas nitrous oxide (N{sub 2}O). Ammonia oxidation can result in N{sub 2}O emissions, either directly or by fuelling denitrification, but we know little about the ecology of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in peat soils. Our aim was to determine temporal alterations in abundance and composition of these communities in a drained and forested peat soil in relation to N{sub 2}O emissions and ammonia oxidation activity. Materials and methods The peat was sampled at three different depths in the upper 0.5 m over a period of 9 months covering two summer and two winter samplings. Community composition and abundance were determined by T-RFLP and quantitative real-time PCR of the bacterial and archaeal amoA genes. Potential ammonia oxidation rates were measured using the chlorate inhibition technique, and in situ N{sub 2}O emission was determined using chambers. Results and discussion The soil parameters displayed little spatial and temporal heterogeneity, which probably explained why there were no depth-related effects on the abundance, composition, or activity of the ammonia oxidizers. In contrast to most terrestrial environments, the AOB dominated numerically over the AOA. Both groups changed in community composition between sampling occasions, although the AOB showed more significant seasonal signatures than the AOA. Temporal changes in abundance were only observed for the AOB, with a decrease in numbers from May to March. Such differences were not reflected by the activity or N{sub 2}O emissions. Conclusions The high ammonium concentrations in the peat soil likely favored the AOB over the AOA, and we hypothesize that they were more active than the AOA and therefore responded to climatic and environmental changes. However, other processes rather than ammonia oxidation were likely responsible for N{sub 2}O emissions at the site.

  16. Influence of Oxychlorine Phases During the Pyrolysis of Organic Molecules: Implications for the Quest of Organics on Mars with the SAM Experiment Onboard the Curiosity Rover (United States)

    Millan, M.; Szopa, C.; Buch, A.; Belmahdi, I.; Glavin, D. P.; Freissinet, C.; Eigenbrode, J. L.; Archer, P. D., Jr,; Sutter, B.; Mahaffy, P.


    One among the main objectives of the Sample Analysis at Mars (SAM) experiment is the in situ molecular analysis of gases evolving from solid samples heated up to approximately 850 degrees Centigrade, and collected by Curiosity on Mars surface/sub-surface in Gale crater. With this aim, SAM uses a gas-chromatograph coupled to a quadrupole mass spectrometer (GC-QMS) devoted to separate, detect and identify both volatile inorganic and organic compounds. SAM detected chlorinated organic molecules produced in evolved gas analysis (EGA) experiments. Several of these were also detected by the Viking experiments in 1976. SAM also detected oxychlorine compounds that were present at the Phoenix landing site. The oxychlorines may be prevelant over much of the martian surface. The C1 to C3 aliphatic chlorohydrocarbons (chloromethane and di- and trichloromethane) detected by SAM were attributed to reaction products occurring between the oxychlorines phases and the organic compounds coming from SAM instrument background. But SAM also showed the presence of a large excess of chlorobenzene and C2 to C4 dichloroalkanes among the volatile species released by the Cumberland sample of the Sheepbed mudstone. For the first time in the history of the Mars exploration, this proved the presence of Mars indigenous organic material at the Mars' surface. However, the identification of the precursor organic compounds of these chlorohydrocarbons is difficult due to the complexity of the reactions occurring during the sample pyrolysis. Laboratory pyrolysis experiments have demonstrated that oxychlorines phases such as perchlorates and chlorates, decomposed into dioxygen and volatile chlorine bearing molecules (HCl and/or Cl2) during the pyrolysis. These chemical species can then react with the organic molecules present in the martian solid samples through oxidation, chlorination and oxychlorination processes.

  17. Characterization of dissolved organic material in the interstitial brine of Lake Vida, Antarctica (United States)

    Cawley, Kaelin M.; Murray, Alison E.; Doran, Peter T.; Kenig, Fabien; Stubbins, Aron; Chen, Hongmei; Hatcher, Patrick G.; McKnight, Diane M.


    Lake Vida (LV) is located in the McMurdo Dry Valleys (Victoria Valley, East Antarctica) and has no inflows, outflows, or connectivity to the atmosphere due to a thick (16 m), turbid ice surface and cold (low salt sub-fractions and allowed comparison to other Antarctic lake DOM samples isolated using similar procedures. Compared to other Antarctic lakes, a lower portion of the DOC was retained by XAD-8 (∼10% vs. 16-24%) resin, while the portions retained by XAD-4 (∼8%) resin and the 1 kDa ultrafiltration membrane (∼50%) were similar. The 14C radiocarbon ages of the XAD-8 (mean 3940 ybp), XAD-4 (mean 4048 ybp) and HMW (mean 3270 ybp) fractions are all older than the apparent age of ice-cover formation (2800 ybp). Ultrahigh resolution mass spectrometry showed that compounds with two and three nitrogen atoms in the molecular formulas were common in both the LV-XAD8 and LV-XAD4 fractions, consistent with microbial production and processing. The long-term oxidation of LVBr DOM by abiotic oxidants including perchlorate and chlorate may explain the low portion in the XAD8 fraction and the lack of aromatic carbon, as measured by 13C NMR spectroscopy, found for all but the most hydrophobic fraction, LV-XAD8. Overall, the chemical characteristics of Lake Vida brine DOM suggest that legacy DOM sealed and concentrated within the brine has been altered due to a combination of both biological and abiotic chemical reactions.

  18. Photochemical oxidation of chloride ion by ozone in acid aqueous solution. (United States)

    Levanov, Alexander V; Isaykina, Oksana Ya; Amirova, Nazrin K; Antipenko, Ewald E; Lunin, Valerii V


    The experimental investigation of chloride ion oxidation under the action of ozone and ultraviolet radiation with wavelength 254 nm in the bulk of acid aqueous solution at pH 0-2 has been performed. Processes of chloride oxidation in these conditions are the same as the chemical reactions in the system O3 - OH - Cl(-)(aq). Despite its importance in the environment and for ozone-based water treatment, this reaction system has not been previously investigated in the bulk solution. The end products are chlorate ion ClO3(-) and molecular chlorine Cl2. The ions of trivalent iron have been shown to be catalysts of Cl(-) oxidation. The dependencies of the products formation rates on the concentrations of O3 and H(+) have been studied. The chemical mechanism of Cl(-) oxidation and Cl2 emission and ClO3(-) formation has been proposed. According to the mechanism, the dominant primary process of chloride oxidation represents the complex interaction with hydroxyl radical OH with the formation of Cl2(-) anion-radical intermediate. OH radical is generated on ozone photolysis in aqueous solution. The key subsequent processes are the reactions Cl2(-) + O3 → ClO + O2 + Cl(-) and ClO + H2O2 → HOCl + HO2. Until the present time, they have not been taken into consideration on mechanistic description and modelling of Cl(-) oxidation. The final products are formed via the reactions 2ClO → Cl2O2, Cl2O2 + H2O → 2H(+) + Cl(-) + ClO3(-) and HOCl + H(+) + Cl(-) ⇄ H2O + Cl2. Some portion of chloride is oxidized directly by O3 molecule with the formation of molecular chlorine in the end.

  19. Role of phosphate and other proton-donating anions in respiration-coupled transport of Ca2+ by mitochondria. (United States)

    Lehninger, A L


    Measurements of extra oxygen consumption, (45)Ca(2+) uptake, and the osmotic expansion of the matrix compartment show that not all permeant anions are capable of supporting and accompanying the energy-dependent transport of Ca(2+) from the medium into the matrix in respiring rat-liver mitochondria. Phosphate, arsenate, acetate, butyrate, beta-hydroxybutyrate, lactate, and bicarbonate + CO(2) supported Ca(2+) uptake, whereas the permeant anions, nitrate, thiocyanate, chlorate, and perchlorate, did not. The active anions share a common denominator, the potential ability to donate a proton to the mitochondrial matrix; the inactive anions lack this capacity. Phosphate and the other active permeant anions move into the matrix in response to the alkaline-inside electrochemical gradient of protons generated across the mitochondrial membrane by electron transport, thus forming a negative-inside anion gradient. It is postulated that the latter gradient is the immediate "pulling" force for the influx of Ca(2+) on the electrogenic Ca(2+) carrier in respiring mitochondria under intracellular conditions. Since mitochondria in the cell are normally exposed to an excess of phosphate (and the bicarbonate-CO(2) system), particularly in state 4, inward transport of these proton-yielding anions probably precedes and is necessary for inward transport of Ca(2+) and other cations under biological conditions. These observations indicate that a negative-inside gradient of phosphate generated by electron transport is a common step and provides the immediate motive power not only for (a) the inward transport of dicarboxylates and tricarboxylates and (b) the energy-dependent exchange of external ADP(3-) for internal ATP(4-) during oxidative phosphorylation, as has already been established, but also for (c) the inward transport of Ca(2+), K(+), and other cations.

  20. Probing for the Activities of Arsenic and Selenium Metabolizing Microbes (United States)

    Stolz, J. F.


    Microbial activities can directly impact the mobility and toxicity of arsenic and selenium in the environment. Arsenic is cycled through oxidation/reduction and methylation/demethylation reactions as part of resistance and respiratory processes. The requirement for selenium is primarily for incorporation into selenocysteine and its function in selenoenzymes. Selenium oxyanions can also serve as an electron acceptor in anaerobic respiration. Both culture and culture-independent methods have been developed to detect the presence and activity of organisms capable of arsenic and selenium transformations. Enrichment media have been successful at cultivating arsenate respiring bacteria from a variety of environments, however, both electron donor and the concentration of arsenic can exert strong selective pressure. Thus, the organisms in the enrichment culture may not be the dominant organisms in the environment. Culture-independent methods, including immunological approaches (e.g., polyclonal antibodies to ArrA) and PCR-based technologies, have also had mixed success. PCR-primers designed to amplify portions of genes involved in resistance (e.g., arsC, acr3), respiration (e.g., arrA), and oxidation (e.g., aoxB) have been useful in several environments. Applications include T-RFLP, rt-PCR, and DGGE analyses. Nevertheless, these primers do not work with certain organisms suggesting the existence of additional enzymes and pathways. Although the biosynthetic pathway (and the proteins involved) for selenocysteine has been described in detail, much less is known about selenium methylation, assimilation and respiration. Only one respiratory selenate reductase has been characterized and its close sequence identity with chlorate and perchlorate reductases has complicated efforts to design a functional probe. Thus many aspects of the biogeochemical cycle of selenium remains to be explored.

  1. Tyrosine sulfation of the amino terminus of PSGL-1 is critical for enterovirus 71 infection.

    Directory of Open Access Journals (Sweden)

    Yorihiro Nishimura

    Full Text Available Enterovirus 71 (EV71 is one of the major causative agents of hand, foot, and mouth disease, a common febrile disease in children; however, EV71 has been also associated with various neurological diseases including fatal cases in large EV71 outbreaks particularly in the Asia Pacific region. Recently we identified human P-selectin glycoprotein ligand-1 (PSGL-1 as a cellular receptor for entry and replication of EV71 in leukocytes. PSGL-1 is a sialomucin expressed on the surface of leukocytes, serves as a high affinity counterreceptor for selectins, and mediates leukocyte rolling on the endothelium. The PSGL-1-P-selectin interaction requires sulfation of at least one of three clustered tyrosines and an adjacent O-glycan expressing sialyl Lewis x in an N-terminal region of PSGL-1. To elucidate the molecular basis of the PSGL-1-EV71 interaction, we generated a series of PSGL-1 mutants and identified the post-translational modifications that are critical for binding of PSGL-1 to EV71. We expressed the PSGL-1 mutants in 293T cells and the transfected cells were assayed for their abilities to bind to EV71 by flow cytometry. We found that O-glycosylation on T57, which is critical for PSGL-1-selectin interaction, is not necessary for PSGL-1 binding to EV71. On the other hand, site-directed mutagenesis at one or more potential tyrosine sulfation sites in the N-terminal region of PSGL-1 significantly impaired PSGL-1 binding to EV71. Furthermore, an inhibitor of sulfation, sodium chlorate, blocked the PSGL-1-EV71 interaction and inhibited PSGL-1-mediated viral replication of EV71 in Jurkat T cells in a dose-dependent manner. Thus, the results presented in this study reveal that tyrosine sulfation, but not O-glycosylation, in the N-terminal region of PSGL-1 may facilitate virus entry and replication of EV71 in leukocytes.


    Institute of Scientific and Technical Information of China (English)

    叶必雄; 王五一; 杨林生; 王小龙; 魏建荣


    In an effect to explore the production mechanisms and characteristics of the by-products in different water disinfection processes,and to investigate the effect of chlorine dioxide on the formation of chlorine by-products,water samples from 4 water plants in a city in China were analyzed.Compared with the water disinfected with chlorine alone,the amount of THMs and HAAs decreased by 74.39% and 40.65%,respectively,in water samples disinfected with both chlorine dioxide and chlorine.Likewise,the amounts of chlorate and chlorite produced by the chlorine dioxide chemical generator was higher than that of the pure chlorine dioxide generator.%为了研究二氧化氯与氯联合消毒工艺过程中消毒副产物的形成规律以及特点,探讨二氧化氯对氯化消毒副产物的控制效果,对我国北方某市使用同一水源的4家水厂消毒工艺进行全面的采样与检测,并对各项消毒副产物检测结果进行了全面的分析.结果表明,二氧化氯与氯联合消毒比单纯液氯消毒形成的三卤甲烷平均降低74.39%,卤乙酸平均降低40.65%.在控制氯酸盐及亚氯酸盐生成方面,使用纯二氧化氯发生器生成的氯酸盐要显著低于化学法复合二氧化氯发生器.

  3. Clinical application of therapeutic erythrocytapheresis (TEA). (United States)

    Valbonesi, M; Bruni, R


    Therapeutic erythrocytapheresis (TEA) has been used in different diseases such as polycythemia vera (PV), secondary erythrocytosis or hemochromatosis as a process of the less cumbersome but more expensive phlebotomy. TEA is preferred in emergency conditions such as thrombocytosis or in conditions such as porphyria cutanea tarda (PCT) or erythropoietic porphyria when plasma exchange (PEX) is often combined with TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity. TEA is often combined with drug therapy that varies from etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce iron stores in hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for TEA, there is no standard protocol and, clinical experience with this therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe anemia in thalassemia patients thereby preventing iron overload. It has also been used for the management of complications of sickle cell disease such as priapism, chest syndrome, stroke, retinal, bone, splenic and hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated apheresis has also favored the use of TREX in conditions such as paroxysmal nocturnal hemoglobinuria and aniline poisoning, arsenic poisoning, Na chlorate intoxications and CO intoxications, hemoglobinopathies, autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible bone marrow transplantation or for preventing anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic parasite infections such as malaria and babesiosis. Application of TREX may be wide but its real use remains limited

  4. Identification of inorganic improvised explosive devices using sequential injection capillary electrophoresis and contactless conductivity detection. (United States)

    Blanco, Gustavo A; Nai, Yi H; Hilder, Emily F; Shellie, Robert A; Dicinoski, Greg W; Haddad, Paul R; Breadmore, Michael C


    A simple sequential injection capillary electrophoresis (SI-CE) instrument with capacitively coupled contactless conductivity detection (C(4)D) has been developed for the rapid separation of anions relevant to the identification of inorganic improvised explosive devices (IEDs). Four of the most common explosive tracer ions, nitrate, perchlorate, chlorate, and azide, and the most common background ions, chloride, sulfate, thiocyanate, fluoride, phosphate, and carbonate, were chosen for investigation. Using a separation electrolyte comprising 50 mM tris(hydroxymethyl)aminomethane, 50 mM cyclohexyl-2-aminoethanesulfonic acid, pH 8.9 and 0.05% poly(ethyleneimine) (PEI) in a hexadimethrine bromide (HDMB)-coated capillary it was possible to partially separate all 10 ions within 90 s. The combination of two cationic polymer additives (PEI and HDMB) was necessary to achieve adequate selectivity with a sufficiently stable electroosmotic flow (EOF), which was not possible with only one polymer. Careful optimization of variables affecting the speed of separation and injection timing allowed a further reduction of separation time to 55 s while maintaining adequate efficiency and resolution. Software control makes high sample throughput possible (60 samples/h), with very high repeatability of migration times [0.63-2.07% relative standard deviation (RSD) for 240 injections]. The separation speed does not compromise sensitivity, with limits of detection ranging from 23 to 50 μg·L(-1) for all the explosive residues considered, which is 10× lower than those achieved by indirect absorbance detection and 2× lower than those achieved by C(4)D using portable benchtop instrumentation. The combination of automation, high sample throughput, high confidence of peak identification, and low limits of detection makes this methodology ideal for the rapid identification of inorganic IED residues.

  5. Final Technical Report: Genetic Control of Nitrogen Assimilation in Klebsiella oxytoca.

    Energy Technology Data Exchange (ETDEWEB)

    Valley Stewart


    Klebsiella oxytoca, an enterobacterium closely related to Escherichia coli and amenable to molecular genetic analysis, is a long-established model organism for studies of bacterial nitrogen assimilation. Our work concerned utilization of purines, nitrogen-rich compounds that are widespread in the biosphere. This project began with our observation that molybdenum cofactor (chlorate-resistant) mutants can use (hypo)xanthine as sole nitrogen source (Garzón et al., J. Bacteriol. 174:6298, 1992). Since xanthine dehydrogenase is a molybdoenzyme, Klebsiella must use an alternate route for (hypo)xanthine catabolsim. We identified and characterized a cluster of 22 genes that encode the enzymes, permeases and regulators for utilizing hypoxanthine and xanthine as sole nitrogen source. (Hypoxanthine and xanthine arise from deamination of adenine and guanine, respectively.) Growth and complementation tests with insertion mutants, combined with protein sequence comparisons, allow us to assign probable functions for the products of these genes and to deduce the overall pathway. We present genetic evidence that the first two enzymes for the Klebsiella purine utilization pathway have been recruited from pathways involved in catabolism of aromatic compounds. The first, HxaAB enzyme catalyzing (hypo)xanthine oxidation, is related to well-studied aromatic ring hydroxylating oxygenases such as phthalate dioxygenase. The second, HxbA enzyme catalyzing urate hydroxylation, is related to single-component monooxygenases. Thus, the Klebsiella purine utilization pathway has likely experienced non-orthologous gene displacement, substituting these oxygenases for the conventional enzymes, xanthine dehydrogenase and uricase. We also present evidence that transcription of the hxaAB operon is subject to dual regulation: global general nitrogen regulation (Ntr) through an unknown mechanism, and (hypo)xanthine induction mediated by a LysR-type activator.

  6. Detection of Evolved Carbon Dioxide in the Rocknest Eolian Bedform by the Sample Analysis at Mars(SAM) Instrument at the Mars Curiosity Landing Site (United States)

    Sutter, B.; Archer, D.; McAdam, A.; Franz, H.; Ming, D. W.; Eigenbrode, J. L.; Glavin, D. P.; Mahaffy, P.; Stern, J.; Navarro-Gonzalez, R.


    The Sample Analysis at Mars (SAM) instrument detected four releases of carbon dioxide (CO2) that ranged from 100 to 700 C from the Rocknest eolian bedform material (Fig. 1). Candidate sources of CO2 include adsorbed CO2, carbonate(s), combusted organics that are either derived from terrestrial contamination and/or of martian origin, occluded or trapped CO2, and other sources that have yet to be determined. The Phoenix Lander s Thermal Evolved Gas Analyzer (TEGA) detected two CO2 releases (400-600, 700-840 C) [1,2]. The low temperature release was attributed to Fe- and/or Mg carbonates [1,2], per-chlorate interactions with carbonates [3], nanophase carbonates [4] and/or combusted organics [1]. The high temperature CO2 release was attributed to a calcium bearing carbonate [1,2]. No evidence of a high temperature CO2 release similar to the Phoenix material was detected in the Rocknest materials by SAM. The objectives of this work are to evaluate the temperature and total contribution of each Rocknest CO2 release and their possible sources. Four CO2 releases from the Rocknest material were detected by SAM. Potential sources of CO2 are adsorbed CO2, (peak 1) and Fe/Mg carbonates (peak 4). Only a fraction of peaks 2 and 3 (0.01 C wt.%) may be partially attributed to combustion of organic contamination. Meteoritic organics mixed in the Rocknest bedform could be present, but the peak 2 and 3 C concentration (approx.0.21 C wt. %) is likely too high to be attributed solely to meteoritic organic C. Other inorganic sources of C such as interactions of perchlorates and carbonates and sources yet to be identified will be evaluated to account for CO2 released from the thermal decomposition of Rocknest material.

  7. Identification of improvised explosives residues using physical-chemical analytical methods under real conditions after an explosion (United States)

    Kotrlý, Marek; Mareš, Bohumil; Turková, Ivana; Beroun, Ivo


    Within the analysis of cases relating to the use of explosives for crimes, we have experienced a shift from using industrial explosives towards substances made in amateur and illegal way. Availability of industrial explosives is increasingly limited to a narrow sphere of subjects with a relevant permission. Thus, on the part of perpetrators, terrorists, ever greater attention is paid to illegal production of explosives that are easily made from readily available raw materials. Another alarming fact is the availability of information found on the internet. Procedures of preparation are often very simple and do not require even a deeper professional knowledge. Explosive characteristics are not actually accessible for many of these substances (detonation velocity, sensitivity, working capacity, brisance, physical and chemical stability, etc.). Therefore, a project is being implemented, which on grounds of assessment of individual information available in literature and on the internet, aiming at choosing individual areas of potentially abusable substances (e.g. mixtures of nitric acid (98%) with organic substances, mixtures nitromethane and tetranitromethane with organic substances, mixtures of chlorates and perchlorates of alkali metals with organic substances, chemically individual compounds of organic base type of perchloric acid, azides, fulminates, acetylides, picrates, styphnates of heavy metals, etc.). It is directed towards preparation of these explosives also in non-stoichiometric mixtures, conducting test explosives, determination of explosive characteristics (if they are unknown) and analysis of both primary phases and post-blast residues through available analytical techniques, such as gas and liquid chromatography with mass detection, FTIR, micro-Raman spectrometry, electron microscopy with microanalysis and Raman microspectrometry directly in SEM chamber for analysis at the level of individual microparticles. The received characteristics will be used to

  8. Proteoglycans act as cellular hepatitis delta virus attachment receptors. (United States)

    Lamas Longarela, Oscar; Schmidt, Tobias T; Schöneweis, Katrin; Romeo, Raffaella; Wedemeyer, Heiner; Urban, Stephan; Schulze, Andreas


    The hepatitis delta virus (HDV) is a small, defective RNA virus that requires the presence of the hepatitis B virus (HBV) for its life cycle. Worldwide more than 15 million people are co-infected with HBV and HDV. Although much effort has been made, the early steps of the HBV/HDV entry process, including hepatocyte attachment and receptor interaction are still not fully understood. Numerous possible cellular HBV/HDV binding partners have been described over the last years; however, so far only heparan sulfate proteoglycans have been functionally confirmed as cell-associated HBV attachment factors. Recently, it has been suggested that ionotrophic purinergic receptors (P2XR) participate as receptors in HBV/HDV entry. Using the HBV/HDV susceptible HepaRG cell line and primary human hepatocytes (PHH), we here demonstrate that HDV entry into hepatocytes depends on the interaction with the glycosaminoglycan (GAG) side chains of cellular heparan sulfate proteoglycans. We furthermore provide evidence that P2XR are not involved in HBV/HDV entry and that effects observed with inhibitors for these receptors are a consequence of their negative charge. HDV infection was abrogated by soluble GAGs and other highly sulfated compounds. Enzymatic removal of defined carbohydrate structures from the cell surface using heparinase III or the obstruction of GAG synthesis by sodium chlorate inhibited HDV infection of HepaRG cells. Highly sulfated P2XR antagonists blocked HBV/HDV infection of HepaRG cells and PHH. In contrast, no effect on HBV/HDV infection was found when uncharged P2XR antagonists or agonists were applied. In summary, HDV infection, comparable to HBV infection, requires binding to the carbohydrate side chains of hepatocyte-associated heparan sulfate proteoglycans as attachment receptors, while P2XR are not actively involved.

  9. Role of Heparan Sulfate in Cellular Infection of Integrin-Binding Coxsackievirus A9 and Human Parechovirus 1 Isolates. (United States)

    Merilahti, Pirjo; Karelehto, Eveliina; Susi, Petri


    Heparan sulfate/heparin class of proteoglycans (HSPG) have been shown to function in cellular attachment and infection of numerous viruses including picornaviruses. Coxsackievirus A9 (CV-A9) and human parechovirus 1 (HPeV-1) are integrin-binding members in the family Picornaviridae. CV-A9 Griggs and HPeV-1 Harris (prototype) strains have been reported not to bind to heparin, but it was recently shown that some CV-A9 isolates interact with heparin in vitro via VP1 protein with a specific T132R/K mutation. We found that the infectivity of both CV-A9 Griggs and HPeV-1 Harris was reduced by sodium chlorate and heparinase suggestive of HSPG interactions. We analyzed the T132 site in fifty-four (54) CV-A9 clinical isolates and found that only one of them possessed T132/R mutation while the other nine (9) had T132K. We then treated CV-A9 Griggs and HPeV-1 Harris and eight CV-A9 and six HPeV-1 clinical isolates with heparin and protamine. Although infectivity of Griggs strain was slightly reduced (by 25%), heparin treatment did not affect the infectivity of the CV-A9 isolates that do not possess the T132R/K mutation, which is in line with the previous findings. Some of the HPeV-1 isolates were also affected by heparin treatment, which suggested that there may be a specific heparin binding site in HPeV-1. In contrast, protamine (a specific inhibitor of heparin) completely inhibited the infection of both prototypes and clinical CV-A9 and HPeV-1 isolates. We conclude that T132R/K mutation has a role in heparin binding of CV-A9, but we also show data, which suggest that there are other HSPG binding sites in CV-A9. In all, we suggest that HSPGs play a general role in both CV-A9 and HPeV-1 infections.

  10. Primary retention following nuclear recoil in β-decay: Proposed synthesis of a metastable rare gas oxide ((38)ArO4) from ((38)ClO4(-)) and the evolution of chemical bonding over the nuclear transmutation reaction path. (United States)

    Timm, Matthew J; Matta, Chérif F


    Argon tetroxide (ArO4) is the last member of the N=50 e(-) isoelectronic and isosteric series of ions: SiO4(4-), PO4(3-), SO4(2-), and ClO4(-). A high level computational study demonstrated that while ArO4 is kinetically stable it has a considerable positive enthalpy of formation (of ~298kcal/mol) (Lindh et al., 1999. J. Phys. Chem. A 103, pp. 8295-8302) confirming earlier predictions by Pyykkö (1990. Phys. Scr. 33, pp. 52-53). ArO4 can be expected to be difficult to synthesize by traditional chemistry due to its metastability and has not yet been synthesized at the time of writing. A computational investigation of the changes in the chemical bonding of chlorate (ClO4(-)) when the central chlorine atom undergoes a nuclear transmutation from the unstable artificial chlorine isotope (38)Cl to the stable rare argon isotope (38)Ar through β-decay, hence potentially leading to the formation of ArO4, is reported. A mathematical model is presented that allows for the prediction of yields following the recoil of a nucleus upon ejecting a β-electron. It is demonstrated that below a critical angle between the ejected β-electron and that of the accompanying antineutrino their respective linear momentums can cancel to such an extent as imparting a recoil to the daughter atom insufficient for breaking the Ar-O bond. As a result, a primary retention yield of ~1% of ArO4 is predicted following the nuclear disintegration. The study is conducted at the quadratic configuration interaction with single and double excitations [QCISD/6-311+G(3df)] level of theory followed by an analysis of the electron density by the quantum theory of atoms in molecules (QTAIM). Crossed potential energy surfaces (PES) were used to construct a PES from the metastable ArO4 ground singlet state to the Ar-O bond dissociation product ArO3+O((3)P) from which the predicted barrier to dissociation is ca. 22kcal/mol and the exothermic reaction energy is ca. 28kcal/mol [(U)MP2/6-311+G(d)].

  11. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Directory of Open Access Journals (Sweden)

    B. Veuger


    Full Text Available Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate in combination with compound-specific stable isotope (13C analysis of bacterial- and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N l−1h−1. Ammonium assimilation was always substantially lower than nitrification with nitrification on average contributing 89% (range 73–97% to total ammonium consumption.

    13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95%. The inhibitor-sensitive 13C-PLFA pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. Cell-specific 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance

  12. 白云鄂博氟碳铈矿-独居石混合精矿中非稀土元素的氯化反应%Carbochlorination of Non- rare Earth Elements in Baiyunebo Mixed Bastnaesite- monazite Concentrate

    Institute of Scientific and Technical Information of China (English)

    张丽清; 赵玲燕; 周华锋; 于秀兰


    The isothermal carbochlorination reaction of non-rare earth element in Baiyunebo mixed bastnaesite-mon azite concentrate and the change of its physical states in this process were investigated. When the temperature is 500t ,the non-rare earth elements of Ca,Ba and Mg in Baiyunebo mixed bastnaesite-monazite were carbochlorinat ed completely using carbon as reductant,chlorine as chlorination agent,SiCl4 as defluoration agent. Their carbon chloration products were dissolved in water with the carbonchloration products of rare-earth. TiCl4 mainly exit in the insoluble residues, less than 1 % of which was vaporized in the carbochlorination process and deposited in the recep tors around 450^. FeCl3 was deposited in the receptors at 300t to 150T!. POC13 was deposited in the receptors below 150t. The separation of Fe, P Th from other substances and the separation of a little substance which was not carbonchlorated from carbonchloration products can be realized by dissolved the carbonchloration products in water.%研究了白云鄂博氟碳铈矿-独居石混合精矿中非稀土元素的等温碳热氯化反应以及反应过程中物理状态的变化.当反应温度低至500℃、活性炭为还原剂、SiCl4+ Cl2的气氛下氟碳铈-独居石混合精矿中非稀土元素Ca、Ba、Mg基本反应完全并和稀土元素的氯化产物共同存在于氯化产物水溶液中,Th的氯化产物主要存在于氯化产物的水不溶物中,小于1%的ThCl4在反应过程中挥发,沉积在450℃的温区,精矿中Fe的氯化产物沉积在300℃-150℃的温区,P的氯化产物主要沉积在低于150℃的温区内.通过水溶氯化反应产物可实现少量的没有氯化的物质和氯化物之间的分离以及Fe、P、Th的分离.

  13. pH-Controlled assembly of two novel Dawson-sandwiched clusters involving the in situ reorganization of trivacant α-[P2W15O56](12-) into divacant α-[P2W16O57](8.). (United States)

    Guo, Ling-Yu; Jagodič, Marko; Zeng, Su-Yuan; Wang, Zhi; Shi, Zhi-Qiang; Wang, Xing-Po; Tung, Chen-Ho; Sun, Di


    Modified classical trivacant Wells-Dawson α-[P2W15O56](12-) and the assembly of related sandwiched transition metal clusters are of interest, but surprisingly few reports of these materials exist because of the sensitivity of α-[P2W15O56](12-) to the assembly environment. Herein, we describe the pH-controlled assembly of two novel Dawson-sandwiched clusters, (H2bpz)6[Co2(P2W16O57)2]·22H2O (1, bpz = 3,3',5,5'-tetramethyl-4,4'-bipyrazole) and (H2bpz)6[Co3H2(P2W16O57)(P2W15O56)(H2O)]·12H2O (2), involving the in situ transformation of α-[P2W15O56](12-). Both clusters were characterized by X-ray single-crystal diffraction, FT-IR spectroscopy, UV-Visible spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and elemental analyses. X-ray crystallography showed that both heteropolytungstates become divacant α-[P2W16O57](8-) and symmetrically encapsulate two edge-shared CoO6 octahedra in the interior in 1, while only one divacant α-[P2W16O57](8-) is observed in 2, which combined with another trivacant α-[P2W15O56](12-) to asymmetrically clamp three edge-shared CoO6 octahedra. The α-[P2W16O57](8-) heteropolytungstate should be generated in situ from α-[P2W15O56](12-)via self-decomposition equilibria in solution. Their electrochemical behaviors reveal characteristic multi-electron redox processes related to W(VI) centers. The electrocatalytic reduction performances toward nitrite, hydrogen peroxide, chlorate, bromate and iodate were fully measured and discussed; among these species, both clusters exhibit the best electrocatalytic activity towards the reduction of bromate. Magnetic measurements indicate weak ferromagnetic exchange interactions between Co atoms sandwiched by vacant polyoxometalates.

  14. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea (United States)

    Veuger, Bart; Pitcher, Angela; Schouten, Stefan; Sinninghe Damsté, Jaap S.; Middelburg, Jack J.


    A dual stable isotope (15N and 13C) tracer approach in combination with compound-specific stable isotope analysis of bacterial and Thaumarchaeotal lipid biomarkers was used to investigate nitrification and the associated growth of autotrophic nitrifiers in the Dutch coastal North Sea. This study focusses on the stoichiometry between nitrification and DIC fixation by autotrophic nitrifiers as well as on the contributions of bacteria versus Thaumarchaeota to total autotrophic DIC-fixation by nitrifiers. Water from the dutch coastal North Sea was collected at weekly to biweekly intervals during the winter of 2007-2008. Watersamples were incubated with 15N-labeled ammonium and 15N was traced into nitrate and suspended material to quantify rates of nitrification and ammonium assimilation respectively. Growth of autotrophic nitrifiers was measured by incubating water samples with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) and subsequent analysis of 13C in bacterial phospholipid-derived fatty acids (PLFAs) and the Thaumarchaeotal biomarker crenarchaeol. Results revealed high nitrification rates with nitrification being the primary sink for ammonium. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27-95%). The ratio between rates of nitrification versus DIC fixation by nitrifiers was higher or even much higher than typical values for autotrophic nitrifiers, indicating that little DIC was fixed relative to the amount of energy that was generated by nitrification, and hence that other other processes for C acquisition may have been relevant as well. The inhibitor-sensitive 13C-PLFA pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. Cell-specific 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the

  15. Influence of ultrasound enhancement on chlorine dioxide consumption and disinfection by-products formation for secondary effluents disinfection. (United States)

    Zhou, Xiaoqin; Zhao, Junyuan; Li, Zifu; Lan, Juanru; Li, Yajie; Yang, Xin; Wang, Dongling


    Chlorine dioxide (ClO2) has been promoted as an alternative disinfectant because of its high disinfection efficiency and less formation of organic disinfection by-products (DBPs). However, particle-associated microorganisms could be protected during the disinfection process, which decreases the disinfection efficiency or increases the required dosage. Besides, the formation of inorganic disinfection by-products is a significant concern in environment health. Ultrasound (US)-combined disinfection methods are becoming increasingly attractive because they are efficient and environmentally friendly. In this study, US was introduced as an enhancement method to identify its influence on ClO2 demand reduction and to minimize the production of potential DBPs for secondary effluents disinfection. Fecal coliform was used as an indicator, and DBPs, including trichloromethane (TCM), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), chlorite (ClO2(-)), and chlorate (ClO3(-)), were analyzed to observe the potential DBPs formation. Results show that US pretreatment could reduce half of ClO2 dosage compared with ClO2 disinfection alone for the same disinfection efficiency, and that an input power density of 2.64 kJ/L pretreatment with the 1.5mg/L ClO2 was enough to meet the discharge requirement in China (i.e., fecal coliform below 1000 CFU/L for Class 1A) for secondary effluent disinfection, and the ClO2(-) concentration in the disinfection effluent was only 1.37 mg/L at the same time. Furthermore, the different effects of US on the two processes (US as pretreatment and simultaneous US/ClO2 disinfection) were also analyzed, including deagglomerating, cell damage, and synergistic disinfection as well as degasing/sonolysis. It was proved that the production of TCM, DCAA, and TCAA was insignificantly influenced with the introduction of US, but US pretreatment did reduce the production of ClO2(-) and ClO3(-) effectually. In general, US pretreatment could be a better option for

  16. Chloroxyanion Residue Quantification in Cantaloupes Treated with Chlorine Dioxide Gas. (United States)

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


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

  17. C-Terminal Amino Acids 471-507 of Avian Hepatitis E Virus Capsid Protein Are Crucial for Binding to Avian and Human Cells. (United States)

    Zhang, Xinquan; Bilic, Ivana; Marek, Ana; Glösmann, Martin; Hess, Michael


    The infection of chickens with avian Hepatitis E virus (avian HEV) can be asymptomatic or induces clinical signs characterized by increased mortality and decreased egg production in adult birds. Due to the lack of an efficient cell culture system for avian HEV, the interaction between virus and host cells is still barely understood. In this study, four truncated avian HEV capsid proteins (ORF2-1 - ORF2-4) with an identical 338aa deletion at the N-terminus and gradual deletions from 0, 42, 99 and 136aa at the C-terminus, respectively, were expressed and used to map the possible binding site within avian HEV capsid protein. Results from the binding assay showed that three truncated capsid proteins attached to avian LMH cells, but did not penetrate into cells. However, the shortest construct, ORF2-4, lost the capability of binding to cells suggesting that the presence of amino acids 471 to 507 of the capsid protein is crucial for the attachment. The construct ORF2-3 (aa339-507) was used to study the potential binding of avian HEV capsid protein to human and other avian species. It could be demonstrated that ORF2-3 was capable of binding to QT-35 cells from Japanese quail and human HepG2 cells but failed to bind to P815 cells. Additionally, chicken serum raised against ORF2-3 successfully blocked the binding to LMH cells. Treatment with heparin sodium salt or sodium chlorate significantly reduced binding of ORF2-3 to LMH cells. However, heparinase II treatment of LMH cells had no effect on binding of the ORF2-3 construct, suggesting a possible distinct attachment mechanism of avian as compared to human HEV. For the first time, interactions between avian HEV capsid protein and host cells were investigated demonstrating that aa471 to 507 of the capsid protein are needed to facilitate interaction with different kind of cells from different species.

  18. Hidrogeología del delta del Río Adra

    Directory of Open Access Journals (Sweden)

    Benavente, J.


    Full Text Available The geographical delta of the Adra River, comprises a complex aquiferal system running through neogene-quaternary materials, which in turo overlie impermeable Alpujarride metapellitic rocks. The mean average rainfall is some 400 mm, the average temperature above 18°C, and it is calculated that, including infiltration and runoff, the annual rainwater amounts to more than 100 mm. The groundwater in general ranges from bad to mediocre in quality, both for domestic and agricultural use, containing as it does calcic-magnesium sulphates andlor sodium chlorate to quantities of 1 to 4 g/l in solution. The principal source of recharge for the system is from filtration through the permeable bed of the Adra River, with which in hydraulic terms it is closely related. The resources of this system at the moment exceed the demand being put on them and it would be possible to obtain greater benefits from it in an area where a general shortage of water is one of the main factors limiting development.El delta del río Adra, en sentido geográfico, constituye un sistema acuífero de geometría compleja integrado por materiales detríticos neógeno- cuateroarios, cuyo sustrato impermeable está formado por metapelitas alpujárrides. Con una precipitación media anual de 400 mm y temperatura superior a 18 °C se estima una lluvia útil media superior a 100 mm/año. Sus aguas, de calidad mediocre o mala, tanto para uso doméstico como agrícola, presentan facies sulfatada magnésicocálcica o clourada sódica y contenido total en sales disueltas comprendido entre 1 y 4 g/l. La principal fuente de alimentación procede de la recarga a partir del río Adra, con el que guarda estrecha relación hidráulica. Este sistema es actualmente excedentario en recursos y susceptible de un mayor aprovechamiento, en un área en donde la escasez de agua constituye el principal elemento limitativo del desarrollo.

  19. High-Temperature, Perhaps Silicic, Volcanism on Mars Evidenced by Tridymite Detection in High-SiO2 Sedimentary Rock at Gale Crater, Mars (United States)

    Morris, R. V.; Vaniman, D. T.; Blake, D. F.; Gellert, R.; Chipera, S. J.; Rampe, E. B.; Ming, D. W.; Morrison, S. M.; Downs, R. T.; Treiman, A. H.; Yen, A. S.; Achilles, C. N.; Bristow, T. F.; Crisp, J. A.; Des Marais, D. J.; Farmer, J. D.; Fendrich, K. V.; Frydenvang, J.; Graff, T. G.; Grotzinger, J. P.; Morookian, J. M.; Schwenzer, S. P.


    stoichiometry. The XRD-calculated amorphous component was 50 +/- 15 wt%. We constrained the value to 60 wt% because it is the minimum value necessary to give a positive Al2O3 concentration for the amorphous component using APXS data for the post-sieve dump pile (Table 2). The amorphous component has high SiO2 (approx.77 wt%) and high anion (SO3+P2O5+Cl 10 wt%) concentrations. Calculation shows that a cation-anion balance is achieved if the cations in the amorphous component except SiO2 and TiO2, which do not readily form salts, are assumed to be present as amorphous mixed-cation sulfates, phosphates, and chlorides (or perchlorates/ chlorates).

  20. Determination of Tungsten and Molybdenum in Geochemical Exploration Samples by Polarography%催化波极谱法测定化探样品中钨量及钼量

    Institute of Scientific and Technical Information of China (English)

    许卓; 于健; 马建学


    试样经碱熔分解,水提取,铁、锰、铺、镍元素量氢氧化物沉淀与钨、钼分离。在0.34moL/L硫酸-2g/L苯羟乙酸-24g/L氯酸钠-0.08g/L辛兜宁体系中,钨和锢均能产生灵敏的极谱催化波,峰电位约为-0.70V和-0.07V(对饱和日‘汞电极)。方法检出限为WO.29蚓g、Mo0.26μg/g,精密度(RSD,n=12)为W1.21%-10.1%、Mo2.7%~12.4%,准确度(RE,n=12)为W-3.7%-2.33%、Mo-4.79%~3.17%。适用于化探样品中钨钿厄索的连续测定。%The sample was melted with potassium hydroxide and extracted with water. Tungsten and molybdenum were separated from iron, manganese, cobalt and nickel with their hydroxides. In 0.34 moL/L sulfuric acid-2 g/L hydroxyphenylacetic acid-24 g/L sodium chlorate -0.08 g/L cinchonine system, tungsten and molybdenum were produced sensitive polarographic catalytic waves with peak potentials (with a saturated calomel electrode) at -0.70 V and-0.07 V, respectively. The detection limit of tungsten and molybdenum were 0.29/ag/g and 0.26μg/g, respectively. The RSD (n=12) of method were 1.21%-10.1% for W, 2.7 %~12.4 % for Mo. The RE (n=12) of method were -3.7 %-2.33 % for W,-4.79 %-3.17% for Mo. The method has been applied to the continuous determination of tungsten and molybdenum in geochemical exploration samples.

  1. The Effects of Endogenous Mycorrhiza (Glomus spp. on Stand Establishment Rate and Yield of Open Field Tomato Crop

    Directory of Open Access Journals (Sweden)



    Full Text Available Graded seeds of a tomato commercial cultivar (Suta F1 were sown in plugged (30 cm3 foam trays filled with vermiculate. For the half of seeds the substrate was homogenously mixed (10% vol/vol with broken expanded clay biologically activated by immobilized propagules of naturally occurring AM-fungi (Glomus intradadices, Glomus etunicatum, Glomus mosseae, Glomus geosporum, Glomus clarum, supplied by BioSym B.V. For the next half, it was homogenously mixed with free clay particles of the same size with the previous one (10% vol/vol. Thirty days after sowing, tomato seedlings were transplanted in to 200 cm3 plastic pots filled with vermiculite. Either AMF non pre inoculated seedlings (non AMF, or AMF pre inoculated (AMF, were equally divided in three subgroups based on the level of salinity applied in the nutrient solution (0, 50 and 100 mM sodium chlorate. On the day of transplanting and 7 days after transplanting, 10 plants were randomly selected for each experimental plot. For each of them, the dry weight of root (RW, leaf (LA, steam (SW and the whole plant (W was determined and based on that, the relative growth rates (RGR and root relative growth rate (RRGR were calculated and used as the parameters assessing the stand establishment rate of tomato seedlings after transplanting. Additionally, stomata conductance and leaf temperature were measured to assess AMF effects on physiological performance of transplanted seedlings. In order to assess the effect of AM fungi pre inoculation on total yield, parallel with pot transplanting, a field experiment was conducted according to a three replication randomized block design. It was proved that the production of open field tomato can be enhanced by the pre inoculation of AM fungi to tomato transplants at the nursery stage. Due to the pre inoculation of AM fungi, the tomato seedlings can subsequently benefit a faster stand establishment rate and higher vigor which is further reflected to a prolonged

  2. Electron transport to periplasmic nitrate reductase (NapA) of Wolinella succinogenes is independent of a NapC protein. (United States)

    Simon, Jörg; Sänger, Monica; Schuster, Stephan C; Gross, Roland


    The rumen bacterium Wolinella succinogenes grows by respiratory nitrate ammonification with formate as electron donor. Whereas the enzymology and coupling mechanism of nitrite respiration is well known, nitrate reduction to nitrite has not yet been examined. We report here that intact cells and cell fractions catalyse nitrate and chlorate reduction by reduced viologen dyes with high specific activities. A gene cluster encoding components of a putative periplasmic nitrate reductase system (napA, G, H, B, F, L, D) was sequenced. The napA gene was inactivated by inserting a kanamycin resistance gene cassette. The resulting mutant did not grow by nitrate respiration and did not reduce nitrate during growth by fumarate respiration, in contrast to the wild type. An antigen was detected in wild-type cells using an antiserum raised against the periplasmic nitrate reductase (NapA) from Paracoccus pantotrophus. This antigen was absent in the W. succinogenes napA mutant. It is concluded that the periplasmic nitrate reductase NapA is the only respiratory nitrate reductase in W. succinogenes, although a second nitrate-reducing enzyme is apparently induced in the napA mutant. The nap cluster of W. succinogenes lacks a napC gene whose product is thought to function in quinol oxidation and electron transfer to NapA in other bacteria. The W. succinogenes genome encodes two members of the NapC/NirT family, NrfH and FccC. Characterization of corresponding deletion mutants indicates that neither of these two proteins is required for nitrate respiration. A mutant lacking the genes encoding respiratory nitrite reductase (nrfHA) had wild-type properties with respect to nitrate respiration. A model of the electron transport chain of nitrate respiration is proposed in which one or more of the napF, G, H and L gene products mediate electron transport from menaquinol to the periplasmic NapAB complex. Inspection of the W. succinogenes genome sequence suggests that ammonia formation from

  3. Qualité des eaux de la station de traitement de la ville de Skikda, Algérie Essais d'optimisation de la clarification (United States)

    Meghzili, B.; Medjram, M. S.; Achour, S.


    A cause de la sécheresse qui a sévit durant une décennie, la station de traitement de l'eau potable de la ville de Skikda Algérie, en vue de combler le déficit en eau, utilise un mélange des eaux de surface (barrage) et des eaux souterraines (forage). Les résultats des analyses physico-chimiques de ces eaux montrent la présence de micropolluants, notamment le mercure, avec une concentration de 0.035 mg/l pour les eaux de surface et une concentration de 0.02 mg/l pour les eaux souterraines. Ces résultats obtenus, montrent également que la concentration en matières organiques dépasse, pour les deux sources, les normes OMS. Afin de réduire les effets de cette pollution, nous avons calculé les doses nécessaires des différents réactifs utilisés sur la base des essais d'optimisation réalisés en laboratoire. Les résultats obtenus nous ont permis de conclure que les doses de 30 à 60 mg/l de sulfate d'aluminium (S.A) sont nécessaires à une bonne élimination de la turbidité et des matières organiques (M.O) et que l'utilisation du charbon active en poudre (C.A.P) permet la réduction de la teneur en mercure au dessous du seuil admissible. L'utilisation d'un adjuvant (chaux vive) permet d'améliorer les résultats surtout pour la turbidité (4 mg/l). Une préchloration au break point semble intéressante pour améliorer la phase de floculation.

  4. 儿童SPECT脑灌注显像护理的配合及探讨%The study and cooperation of children's care during brain perfusion imaging

    Institute of Scientific and Technical Information of China (English)

    陈红艳; 石宇; 高宙; 贾少微


    Objective Taking good care is a very important part and quality assurance to make a successful study during children's nuclear examination for nervous system. This paper aims at summarizing the caring experience so as to coordinate the SPECT examination better. Methods 140 children underwent brain perfusion imaging in our department. The main procedures are as follows: take psychological care, orally take potassium chlorate 400mg and block out the vision and hearing. Then inject 99mTc-ECD 14.8MBq/kg intravenously.Sedate those in-cooperated patients. The equipment for the examination is SIEMENS E. CAM/ICON SPECT. Results In the 140 cases of brain perfusion imaging, 138 cases were successful, while 2 patients moved their head during the examination. Conclusion Through the care of the 140 patients during the examination, we realize that it is very important to communicate with the children actively to get their cooperation. To those autistic children, the operation should be quick and precise. After the administration of sedative, more attention should be paid to the children's respiration and pulse. Make sure that the imaging reagents are injected into the vessel entirely.%目的探讨儿童神经系统核医学检查中的护理方法,总结护理经验,以更好地配合SPECT检查的需要.方法研究对象为我科140例SPECT脑灌注显像患儿,对患儿进行心理护理,口服过氯酸钾400mg,行视听封闭,静脉注射99mTc-ECD,不配合者使用镇静剂.结果140例患儿行SPECT脑灌注显像,138例检查成功,2例在检查中头部位置移动.结论积极和儿童交流,取得配合.对于Autism的患儿,操作做到既准又快.使用镇静剂后,注意观察患儿的呼吸与脉搏情况;注射时保证显像剂全部注入血管内.

  5. Application of 129I/127I Ratios in Groundwater Studies Conducted at Los Alamos National Laboratory, New Mexico (United States)

    Longmire, P.; Dale, M.; Granzow, K.; Yanicak, S. M.


    Los Alamos National Laboratory (LANL) is an operating nuclear site that has released treated effluents from three plutonium-processing facilities since the mid 1940s. The radioisotope 129I (T1/2 = 15.7 Myrs) derived from235U and 239Pu processing at LANL is locally detected in groundwater above background concentrations. This isotope provides a unique tracer for groundwater investigations conducted at LANL that helps to identify source releases linked to groundwater-flow paths in aquifers subject to binary and ternary mixing of natural- and industrial-derived waters containing chromate and other chemicals. Bromide, chlorate, chloride, nitrate, perchlorate, sulfate, and tritium were associated with multiple outfalls at LANL and, therefore, do not provide unique chemical signatures identifying a specific point of release or source. Natural and anthropogenic ratios of 129I/127I measured in groundwater samples collected at LANL were quantified using accelerator mass spectrometry at Purdue Rare Isotope Measurement Laboratory, Purdue University. Anthropogenic ratios of 129I/127I range from 1,531 X 10-15 to 10,323 X 10-15 within perched-intermediate groundwater present in volcanoclastic and basalt aquifers (210 - 216 m depth). Anthropogenic ratios of 129I/127I range from 359 X 10-15 to 4,350 X 10-15 within the regional aquifer (280 m depth) consisting of volcanoclastic sediments of variable hydraulic properties. Local background ratios of 129I/127I have a narrow range of 171 X 10-15 to 378 X 10-15 in the regional aquifer. Dissolved iodide measured in groundwater at LANL is stable dominantly as iodate. Background concentrations of dissolved iodate (0.1 to 33.2 nM) are less variable compared to anthropogenic iodate (8.0 to 246 nM) in groundwater at the site. Variability in concentrations of anthropogenic iodate is controlled by heterogeneous source releases of iodate over time and non-uniform mixing of groundwater in the different aquifers.

  6. The effectiveness of selected feed and water additives for reducing Salmonella spp. of public health importance in broiler chickens: a systematic review, meta-analysis, and meta-regression approach. (United States)

    Totton, Sarah C; Farrar, Ashley M; Wilkins, Wendy; Bucher, Oliver; Waddell, Lisa A; Wilhelm, Barbara J; McEwen, Scott A; Rajić, Andrijana


    Eating inappropriately prepared poultry meat is a major cause of foodborne salmonellosis. Our objectives were to determine the efficacy of feed and water additives (other than competitive exclusion and antimicrobials) on reducing Salmonella prevalence or concentration in broiler chickens using systematic review-meta-analysis and to explore sources of heterogeneity found in the meta-analysis through meta-regression. Six electronic databases were searched (Current Contents (1999-2009), Agricola (1924-2009), MEDLINE (1860-2009), Scopus (1960-2009), Centre for Agricultural Bioscience (CAB) (1913-2009), and CAB Global Health (1971-2009)), five topic experts were contacted, and the bibliographies of review articles and a topic-relevant textbook were manually searched to identify all relevant research. Study inclusion criteria comprised: English-language primary research investigating the effects of feed and water additives on the Salmonella prevalence or concentration in broiler chickens. Data extraction and study methodological assessment were conducted by two reviewers independently using pretested forms. Seventy challenge studies (n=910 unique treatment-control comparisons), seven controlled studies (n=154), and one quasi-experiment (n=1) met the inclusion criteria. Compared to an assumed control group prevalence of 44 of 1000 broilers, random-effects meta-analysis indicated that the Salmonella cecal colonization in groups with prebiotics (fructooligosaccharide, lactose, whey, dried milk, lactulose, lactosucrose, sucrose, maltose, mannanoligosaccharide) added to feed or water was 15 out of 1000 broilers; with lactose added to feed or water it was 10 out of 1000 broilers; with experimental chlorate product (ECP) added to feed or water it was 21 out of 1000. For ECP the concentration of Salmonella in the ceca was decreased by 0.61 log(10)cfu/g in the treated group compared to the control group. Significant heterogeneity (Cochran's Q-statistic p≤0.10) was observed

  7. The application of the atmosphere control technology for the manned submersible Jiaolong%大气环境控制技术在“蛟龙”号载人潜水器上的应用

    Institute of Scientific and Technical Information of China (English)

    姜磊; 金凤来; 侯德永; 刘帅


    介绍各种类型水下运载器如潜艇、载人深潜器等对载人密闭舱室内大气环境控制的共性要求。针对“蛟龙”号的客观条件,从动力、空间大小、浓度要求等方面分析其对大气环境控制的特殊要求。分析常见的几种密闭环境供氧及二氧化碳吸收技术如物理供氧、电解水、氧烛、超氧化物、一乙醇胺、固态胺、分子筛、碱石灰、氢氧化锂等技术各自的优缺点。在此基础上研制出一套环境控制样机,并将样机随“蛟龙”号载人潜水器进行1000,3000,5000及7000米级海试。海试的圆满成功进一步证实了样机的有效性。%Inthispapersamerequirementsoftheatmospherecontroltechnologyintheclosedspace at various underwater vehicles, such as submarine and manned submersible, are introduced. Based on the objective conditions of Jiaolong, this paper analyzed the particular demand for the atmosphere control technology from the aspects of power, space size and gases concentration. Several O2 supplying methods and CO2 absorption methods in closed space such as peroxide, physical oxygen supply, water electroanalysis, the potassium chlorate pyrogenation, mono ethanol amine( MEA) , molecular sieve, solid amine, soda lime and lithium hydroxide are compared. Based on these methods, a suitable atmosphere control technology and a prototype is developed, and the prototype is set up in the cabin of“Jiaolong” . A series of experiments has been achieved in both the South China Sea and the North-East Pacific. The validity of the prototype is approved by these experiments.

  8. Influence of different disinfecting modes on disinfection efficiency of outlet water from sand filter%不同的消毒方式对砂滤池出水消毒效果的影响

    Institute of Scientific and Technical Information of China (English)

    李芳; 陆少鸣


    Using pilot test with the mid-positioning O3-biological activated carbon filter,influences of different disinfection methods on disinfection efficiency of outlet water from sand filter were researched by the detection and analysis of microorganism,micro aquatic animals,DBPs and AOC.The results showed that the effect of chlorine disinfection was slightly weaker than ozone disinfection combined chlorination in removing microorganisms and micro aquatic animals.For the disinfection by-production of halogenated hydrocarbon and chlorate,chlorine disinfection produced more than ozone disinfection combined chlorination,the bromated is on the same level,while the formaldehyde is the opposite.The average AOC of sand filter effluent with chlorination and with ozone disinfection combined chlorination is 75.93 μg acetic acid carbon/L and 101.23 μg acetic acid carbon/L,respectively.The latter is more than 100 μg acetic acid carbon/L,which is unbeneficial for the biology stability of water distribution system.%采用中置O3-BAC工艺进行中试实验,通过对微生物、微型生物、消毒副产物和AOC进行检测分析,研究了不同的消毒方式对砂滤池出水消毒效果的影响.结果表明,氯消毒对微型生物、微生物的去除效果稍弱于臭氧联合氯消毒;对于消毒副产物而言,氯消毒产生的卤代烃、氯酸盐的含量高于臭氧联合氯消毒,产生的溴酸盐两者处于同一水平,而产生的甲醛则是氯消毒低于臭氧联合氯消毒;氯消毒最终砂滤池出水AOC平均含量75.93 μg乙酸碳/L,臭氧联合氯消毒为101.23μg乙酸碳/L,大于100 μg乙酸碳/L,不利于供水管网的生物稳定性.

  9. Enhanced bromate formation during chlorination of bromide-containing waters in the presence of CuO: Catalytic disproportionation of hypobromous acid

    KAUST Repository

    Liu, Chao


    Bromate (BrO3 -) in drinking water is traditionally seen as an ozonation byproduct from the oxidation of bromide (Br-), and its formation during chlorination is usually not significant. This study shows enhanced bromate formation during chlorination of bromide-containing waters in the presence of cupric oxide (CuO). CuO was effective to catalyze hypochlorous acid (HOCl) or hypobromous acid (HOBr) decay (e.g., at least 104 times enhancement for HOBr at pH 8.6 by 0.2 g L-1 CuO). Significant halate concentrations were formed from a CuO-catalyzed hypohalite disproportionation pathway. For example, the chlorate concentration was 2.7 ± 0.2 μM (225.5 ± 16.7 μg L-1) after 90 min for HOCl (Co = 37 μM, 2.6 mg L-1 Cl2) in the presence of 0.2 g L-1 CuO at pH 7.6, and the bromate concentration was 6.6 ± 0.5 μM (844.8 ± 64 μg L -1) after 180 min for HOBr (Co = 35 μM) in the presence of 0.2 g L-1 CuO at pH 8.6. The maximum halate formation was at pHs 7.6 and 8.6 for HOCl or HOBr, respectively, which are close to their corresponding pKa values. In a HOCl-Br--CuO system, BrO3 - formation increases with increasing CuO doses and initial HOCl and Br- concentrations. A molar conversion (Br - to BrO3 -) of up to (90 ± 1)% could be achieved in the HOCl-Br--CuO system because of recycling of Br - to HOBr by HOCl, whereas the maximum BrO3 - yield in HOBr-CuO is only 26%. Bromate formation is initiated by the formation of a complex between CuO and HOBr/OBr-, which then reacts with HOBr to generate bromite. Bromite is further oxidized to BrO3 - by a second CuO-catalyzed process. These novel findings may have implications for bromate formation during chlorination of bromide-containing drinking waters in copper pipes. © 2012 American Chemical Society.

  10. Gastrointestinal microbial ecology and the safety of our food supply as related to Salmonella. (United States)

    Callaway, T R; Edrington, T S; Anderson, R C; Byrd, J A; Nisbet, D J


    Salmonella causes an estimated 1.3 million human foodborne illnesses and more than 500 deaths each year in the United States, representing an annual estimated cost to the economy of approximately $2.4 billion. Salmonella enterica comprises more than 2,500 serotypes. With this genetic and environmental diversity, serotypes are adapted to live in a variety of hosts, which may or may not manifest with clinical illness. Thus, Salmonella presents a multifaceted threat to food production and safety. Salmonella have been isolated from all food animals and can cause morbidity and mortality in swine, cattle, sheep, and poultry. The link between human salmonellosis and host animals is most clear in poultry. During the early part of the 20th century, a successful campaign was waged to eliminate fowl typhoid caused by Salmonella Gallinarum/Pullorum. Microbial ecology is much like macroecology; environmental niches are filled by adapted and specialized species. Elimination of S. Gallinarum cleared a niche in the on-farm and intestinal microbial ecology that was quickly exploited by Salmonella Enteritidis and other serotypes that live in other hosts, such as rodents. In the years since, human salmonellosis cases linked to poultry have increased to the point that uncooked chicken and eggs are regarded as toxic in the zeitgeist. Salmonellosis caused by poultry products have increased significantly in the past 5 yr, leading to a USDA Food Safety and Inspection Service "Salmonella Attack Plan" that aims to reduce the incidence of Salmonella in chickens below the current 19%. The prevalence of Salmonella in swine and cattle is lower, but still poses a threat to food safety and production efficiency. Thus, approaches to reducing Salmonella in animals must take into consideration that the microbial ecology of the animal is a critical factor that should be accounted for when designing intervention strategies. Use of competitive exclusion, sodium chlorate, vaccination, and bacteriophage

  11. Role of Heparan Sulfate in Cellular Infection of Integrin-Binding Coxsackievirus A9 and Human Parechovirus 1 Isolates.

    Directory of Open Access Journals (Sweden)

    Pirjo Merilahti

    Full Text Available Heparan sulfate/heparin class of proteoglycans (HSPG have been shown to function in cellular attachment and infection of numerous viruses including picornaviruses. Coxsackievirus A9 (CV-A9 and human parechovirus 1 (HPeV-1 are integrin-binding members in the family Picornaviridae. CV-A9 Griggs and HPeV-1 Harris (prototype strains have been reported not to bind to heparin, but it was recently shown that some CV-A9 isolates interact with heparin in vitro via VP1 protein with a specific T132R/K mutation. We found that the infectivity of both CV-A9 Griggs and HPeV-1 Harris was reduced by sodium chlorate and heparinase suggestive of HSPG interactions. We analyzed the T132 site in fifty-four (54 CV-A9 clinical isolates and found that only one of them possessed T132/R mutation while the other nine (9 had T132K. We then treated CV-A9 Griggs and HPeV-1 Harris and eight CV-A9 and six HPeV-1 clinical isolates with heparin and protamine. Although infectivity of Griggs strain was slightly reduced (by 25%, heparin treatment did not affect the infectivity of the CV-A9 isolates that do not possess the T132R/K mutation, which is in line with the previous findings. Some of the HPeV-1 isolates were also affected by heparin treatment, which suggested that there may be a specific heparin binding site in HPeV-1. In contrast, protamine (a specific inhibitor of heparin completely inhibited the infection of both prototypes and clinical CV-A9 and HPeV-1 isolates. We conclude that T132R/K mutation has a role in heparin binding of CV-A9, but we also show data, which suggest that there are other HSPG binding sites in CV-A9. In all, we suggest that HSPGs play a general role in both CV-A9 and HPeV-1 infections.

  12. Cáncer gástrico en Costa Rica: ¿existe o no relación con la cloración del agua para consumo humano?

    Directory of Open Access Journals (Sweden)

    Darner A Mora Alvarado


    significant link between the incidence of GC and the consumption of chlorinated water in Costa Rica. The analysis used the GC-mortality results in 458 districts during the years 1999 to 2002 and the data obtained from the National Water Laboratory on the type of water (chlorinated or not, the number of years of disinfection and the source of the water (underground, surface or mixed. For the statistical analysis, a Standardized Mortality Index (IME and the Pearson correlation coefficient were used. Results showed no relationship between incidence of GC and the chloration of water for human consumption (ACH, even after taking into account the number of years of chloration and also the type of water source used (underground or superficial. Lastly, it is recommended that the Costa Rican Institute of Waters and Sewer Systems (A y A as the leading supplier of drinking water, carry out an educational campaign with the purpose of reducing the lack of user confidence in the consumption of chlorinated ACH. Besides, A y A must promote the study of the relationship of ACH with other types of cancer such as bladder and colorectal cancer.

  13. Microbial degradation of chloroethenes in groundwater systems (United States)

    Bradley, Paul M.

    éthane (DCE) et le chlorure de vinyl (VC). Bien que des études de laboratoire réalisées avec des micro-organismes adaptés aux composés halogénés montrent que la réduction complète en éthane est possible, dans la plupart des nappes la réaction de déchloration par réduction s'arrête apparemment au DCE et au VC. Cependant, des recherches récentes menées sur des sédiments d'un aquifère et d'alluvions ont démontré que l'oxydation microbienne de ces descendants réduits peut se produire de manière significative dans des conditions de redox anérobies. La déchloration par réduction de PCE et de TCE dans des conditions anérobies suivie par une oxydation microbienne anérobie des DCE et VC fournit une piste microbienne possible pour obtenir une dégradation complète des chloroéthanes polluants dans les aquifères. Resumen Los cloroetanos (tetracloroetano PCE y tricloroetano TCE) son contaminantes muy habituales en los acuíferos. Hasta 1980 se consideraba que los cloroetanos no eran biodegradables y, por tanto, los métodos de rehabilitación en acuíferos contaminados con cloroetanos se limitaban al pump-and-treat, generalmente con poco éxito. Posteriormente se vio que, en condiciones reductoras, algunos microorganismos pueden reducir PCE y TCE a unos subproductos menos clorados, como el dicloroetano (DCE) y el cloruro de vinilo (VC). Aunque estudios de laboratorio recientes sugieren que la reducción completa a etano es posible, en la mayoría de los sistemas acuíferos la decloración suele detenerse en los DCE o VC. Sin embargo, investigaciones más recientes en acuíferos y sedimentos fluviales demuestran que la oxidación microbiana de estos subproductos puede ser importante bajo condiciones redox anaerobias. La combinación de la reducción de PCE y TCE en condiciones anaerobias seguida de la oxidación microbiana anaerobia de DCE y VC proporciona un método potencial para la degradación total de los cloroetanos en los sistemas acuíferos.

  14. Sorption properties of modified potato starch

    Directory of Open Access Journals (Sweden)

    Teresa Witczak


    Full Text Available Background. Starch is one of the biopolymers most commonly used in the food industry. In its native form its applications are limited. In contrast, its structure is relatively readily modified using various methods, producing starch derivatives of greatly diverse properties. The primary methods used to change characteristics of starch include acetylation and oxidation. Thus obtained raw materials are used as food additives. Stability of these raw materials and food products to a considerable extent depends on their composition and parameters characterizing storage facilities, i.e. relative humidity and temperature. One of the methods to specify adequate ambient conditions is based on water activity supplemented by sorption isotherms. As a result studies investigating correlations between water activity and moisture content are of importance for the optimization of storage conditions and design of certain food processing procedures. For this reason the aim of this study was to assess the effect of modification (oxidation, acetylation and their combination on sorption properties (described based on sorption isotherms of potato starch. Material and methods. Analyses were conducted on potato starch and its derivatives produced by acetylation, oxidation and co-modification (acetylation coupled with oxidation. Starch was oxidized using sodium chlorate (I, while acetylation was run using anhydrous acetic acid. Sorption isotherms were determined by the static desiccator method. Results were described applying selected mathematical methods equipped with physical interpretations (BET and GAB and empirical models (Halsey, Oswin, Henderson, Pelega, Lewicki, Blahovec-Yanniotis. Calculations were made using non-linear estimation. Results. The greatest water absorbability was found for native potato starch. Modifications caused a decrease in the amount of adsorbed water vapour, dependent on the applied modification. Acetylation resulted in significantly

  15. Asymmetric autocatalysis of pyrimidyl alkanol and its application to the study on the origin of homochirality. (United States)

    Soai, Kenso; Kawasaki, Tsuneomi; Matsumoto, Arimasa


    triggered by the morphology of inorganic chiral crystals such as quartz, sodium chlorate, and cinnabar. Chiral organic crystals of achiral compounds also act as chiral initiators, and during the study of a crystal of cytosine, enantioselective chiral crystal phase transformation of the cytosine crystal was achieved by removal of the water of crystallization in an achiral monohydrate crystal. Enantioselective C-C bond formation was realized on the surfaces of achiral single crystals based on the oriented prochirality of achiral aldehydes. Furthermore, asymmetric autocatalysis of pyrimidyl alkanols is a highly sensitive reaction that can recognize and amplify the significantly small effect of a chiral compound arising solely from isotope substitution of hydrogen, carbon, and oxygen (D/H, (13)C/(12)C, and (18)O/(16)O). These examples show that asymmetric autocatalysis with an amplification of chirality is a powerful tool for correlating the origin of chirality with highly enantioenriched organic compounds. Asymmetric autocatalysis using two β-amino alcohols reveals a reversal of enantioselectivity in the addition of i-Pr2Zn to aldehyde and is one approach toward understanding the mechanism of asymmetric dialkylzinc addition, where heteroaggregates act as the catalytic species.

  16. Charged Properties,Pollutants Removal,and Mechanism of Composite Si-Fe Coagulant%复合硅铁混凝剂荷电性及除污染性能与机理

    Institute of Scientific and Technical Information of China (English)

    付英; 高宝玉


    A new composite polymer,Si-Fe coagulant with various Si/Fe molar ratios,was prepared by using water glass,ferrous sulfate and sodium chlorate by copolymerization.Charged properties of PSF samples taken from different copolymerization times and influence of dilution concentration on PSF Zeta potential were studied with Nano Zetasizer.The pollutants removal by PSF in treating lower temperature and lower turbidity water,and slaughterhouse effluent was explored compared to that by polyferric aluminum(PFA).Results show that the copolymerization between Si and Fe is not a simple electro neutrality process between positive charge of Fe and negative charge of polysilicic acid(PS).PSF is found to be a complexation compound of Si,Fe and many other ions,instead of a simple mixture of raw materials.The Zeta potential of PSF at higher concentration tends to be zero,and tends to increase when diluted,up to 11 mV,whereas the average Zeta potential of PFA is 36.1 mV,and slightly increases when diluted.For lower temperature and lower turbidity water,PSF gives higher CODMn removal by 20% than PFA,and for slaughterhouse effluent,PSF has higher turbidity,CODCr and color removal by 60%、66% and 54% than PFA,respectively.The coagulation mechanism of PSF is the cooperation of charge-neutralization /destabilization,bridging and sweeping.%采用共聚法制备不同Si、Fe摩尔比的复合硅铁(PSF)混凝剂,应用Zeta电位分析仪对PSF共聚反应过程的荷电性及稀释浓度对荷电性的影响进行研究,并对比PSF与复合铝铁(PFA)对低温低浊水及屠宰废水的除污染性能,同时分析PSF的混凝机理.结果表明,硅铁共聚反应不是铁盐的正电与聚硅酸的负电的简单电中和过程,也不是简单的原料混合或是各原料单独自聚的产物,而是硅、铁等的共聚产物.PSF浓度较高时,其Zeta电位几乎均在等电点附近,稀释水解后其荷正电量增加,达到11 mV;而PFA的Zeta电位平均值为36.1 mV,

  17. Determination of Glycine in Milk by HPCE with Ninhydrin Derivatization%茚三酮衍生高效毛细管电泳法测定纯奶中的甘氨酸含量

    Institute of Scientific and Technical Information of China (English)

    邢超; 闫正; 王立卫; 郭莎; 叶伶菊; 赵旭峰


    建立了茚三酮衍生高效毛细管电泳法测定纯奶中甘氨酸含量的方法,该法可选择性测定甘氨酸含量。使用氯化镁为蛋白沉淀剂,沉淀效果较好,研究了甘氨酸-茚三酮聚合物衍生条件,确定最佳实验条件为:未涂层弹性石英毛细管柱(60 cm×75μm,有效长度49 cm),分离缓冲溶液为3.5 mmol磷酸二氢钾-8.2 mmol磷酸氢二钠(pH 6.8),检测波长为570 nm,电泳电压为25 kV,进样压力为25 kPa,进样时间为3 s,电泳温度为室温。甘氨酸的线性范围为2.00~200.00μg/mL,检出限为0.14μg/mL,线性相关系数不小于0.999。甘氨酸的加标回收率为88.7%~107.2%,测定结果的相对标准偏差为2.9%~4.2%(n=6)。该法简便、快速、准确,可用于测定纯奶中甘氨酸含量。%A method for the determination of glycine content in milk by high performance capillary electrophoresis with ninhydrin derivatization was established. The method was used for the selective determination of the glycine content. The derivatization of glycine-ninhydrin polymer was investigated,and the magnesium chlorate was applied to precipitating protein. The optimal experimental conditions were studied. An uncoated capillary (60 cm×75 μm,49 cm effective length) was used with running buffer solution of 3.5 mmol potassium dihydrogen phosphate-8.2 mmol disodium hydrogen phosphate. The detection wavelength was set at 750 nm and the run voltage was 25 kV. The injection time was 3 s at 25 kPa. The experiment was operated at room temperature. The results showed that the linear range for glycine was 2.00-200.00 mg/L,and the detection limit was 0.14μg/mL,the linear correlation coefficient of glycine was more than 0.999. The average recovery of glycine was between 88.7%-107.2%with the relative standard deviations of 2.9%-4.2%(n=6). This method is simple,rapid,and accurate,and it is suitable for the determination of the glycine content in milk.

  18. Calidad físico-química y microbiólogica del agua en parques acuáticos Physicist-chemistry and Microbiological Water Quality in Aquatic Parks

    Directory of Open Access Journals (Sweden)

    Beatriz Helena Díaz-Solano


    establishments. As study zone was chosen the Morelos State, Mexico, which has four water parks. The study analyzed one of these parks, dividing the study as follow: Phase 1 Sampling of water in and out of the park, analyzing physicochemical and microbiological parameters; and Phase 2 Operational evaluation in six pools of water Park, assessing the electrical conductivity, Total Dissolved Solids (TDS, pH, color, turbidity and residual chlorine. The results were compared with Mexican Official Standards, determining whether there is deterioration in the quality of the resource in the operational processes of the parks. The Phase 1 gave as results raised levels in fats and oils (19.0 mg/L, color (100 UPt-Co, fecal coliforms (1.15 · 10(4 NMP/100 mL and total coliforms (1.70 · 10(5 NMP/100 mL. The Phase 2 showed high values of pH (7.9-8.4, diminishing the efficiency in disinfection and a behavior differentiated in conductivity and TDS in swimming pools filtering systems. Since conclusions there decided that the water quality in Water Parks must be controlled in parallel to the operability in swimming pools, the processes of chloration must be standardized. The users are responsible for the deterioration of water and require the generation of an Environmental Management System.

  19. Efeito do cloreto de cálcio na qualidade de melancias minimamente processadas Effect of calcium chloride on the quality of minimally processed watermelon

    Directory of Open Access Journals (Sweden)

    Ana Carolina Almeida Miguel


    Full Text Available Foi avaliada a qualidade de melancias minimamente processadas, tratadas com cloreto de cálcio, durante o armazenamento sob refrigeração. Utilizaram-se melancias 'Crimson Sweet', maduras, adquiridas no comércio de Piracicaba, SP, oriundas do Rio Grande do Sul. Os frutos foram lavados e desinfetados com água clorada (200 mg L-1. A polpa foi cortada em cubos (2,5 cm de aresta, os quais foram imersos, por 3 min nas soluções que corresponderam aos tratamentos, imersão em água pura (controle, solução de cloreto de cálcio a 1%. Em seguida foram escorridos por 3 min, acondicionados em copos de tereftalato de polietileno (PET transparente de 450 mL de capacidade, com tampa, e armazenados sob refrigeração a 10,0 ± 3,2°C e 79% UR. A cada dois dias, os pedaços foram avaliados sensorialmente e quanto à perda de massa fresca, aparência, coloração interna, textura, teores de sólidos solúveis (SS e de acidez titulável (AT, pH, relação SS/AT e conteúdos de ácido ascórbico e de pectinas, solúvel e total. O uso da solução de cloreto de cálcio promoveu maior firmeza na textura de melancias minimamente processadas, porém não se mostrou efetivo no prolongamento da vida útil, que foi de 2 dias do ponto de vista sensorial.This study evaluated the refrigerated storage and quality of minimally processed watermelon treated with calcium chloride. Ripe Crimson Sweet watermelons produced in Rio Grande do Sul State, Brazil, and acquired at a local market in Piracicaba, SP, were washed and the surface sanitized with chlorated water (200 mg L-1. Samples were then cut into pulp cubes (2.5 cm across. Cubes were subjected to two treatments: immersion for 3 min in pure water (control and 1% calcium chloride. Subsequently, the cubes were drained for 3 min and packaged in transparent polyethylene terephthalate cups and stored at 10.0 ? 3.2?C and 79% RH. Every two days cubes from each treatment were sensorially evaluated as well as the loss of fresh

  20. Design, installation, and performance of a multi-layered permeable reactive barrier, Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kaszuba, J. P. (John P.); Longmire, P. A. (Patrick A.); Strietelmeier, E. A. (Elizabeth A.); Taylor, T. P. (Tammy P.); Den-Baars, P. S. (Peter S.)


    engineered structure. Groundwater sampling upgradient, within, and downgradient of the PRB took place from May through August 2003. Concentrations of strontium-90 have diminished by 80% and 40% within the central portion of the phosphate rock (apatite) and bio-barrier cells, respectively. Higher concentrations of this radionuclide occur in groundwater near the north and south perimeters of the two cells. The non-uniform distribution of strontium-90 may result from varying residence time and saturated thickness of pore water. Initial concentrations of nitrate (8-12 parts per million or ppm as nitrate) and perchlorate (0.035 ppm) have been reduced in the phosphate rock and bio-barrier cells to concentrations that are less than method detection limits (0.01 and 0.002 ppm, respectively). Initial microbial analyses suggest the presence of both dissimilatory perchlorate- and nitrate-reducing bacterial populations, along with production of acetate and propionate, and decreasing dissolved oxygen and pH. The dominant group of perchlorate reducers consists of members of the previously described Dechloromonas genus, in the beta subclass of the Proteobacteria, which together with the Dechlorosoma genus are considered to be the dominant genera in circum-neutral mesophilic environments. Groundwater flow through the multiple PRB is taking place at a very slow rate based on similar concentrations of nitrate, perchlorate, chlorate, and chlorite in the upgradient well MCO-4B and downgradient well MCO-5. Concentrations of these constituents also increase within the limestone cell. Decreased precipitation due to extreme drought is probably responsible for decreasing saturated thickness within both the alluvium and PRB, resulting in stagnant conditions. Varying distributions of ammonium, nitrate, sulfate, iron, and manganese within the phosphate rock, bio-barrier, and limestone cells also support this hypothesis.

  1. Destruction and Sequestration of H2O on Mars (United States)

    Clark, Benton


    The availability of water in biologically useable form on any planet is a quintessential resource, even if the planet is in a zone habitable with temperature regimes required for growth of organisms (above -18 °C). Mars and most other planetary objects in the solar system do not have sufficient liquid water at their surfaces that photosynthesis or chemolithoautotrophic metabolism could occur. Given clear evidence of hydrous mineral alteration and geomorphological constructs requiring abundant supplies of liquid water in the past, the question arises whether this H2O only became trapped physically as ice, or whether there could be other, more or less accessible reservoirs that it has evolved into. Salts containing S or Cl appear to be ubiquitous on Mars, having been measured in soils by all six Mars landed missions, and detected in additional areas by orbital investigations. Volcanoes emit gaseous H2S, S, SO2, HCl and Cl2. A variety of evidence indicates the geochemical fate of these gases is to be transformed into sulfates, chlorides, chlorates and perchlorates. Depending on the gas, the net reaction causes the destruction of between one and up to eight molecules of H2O per atom of S or Cl (although hydrogen atoms are also released, they are lost relatively rapidly to atmospheric escape). Furthermore, the salt minerals formed often incorporate H2O into their crystalline structures, and can result in the sequestration of up to yet another six (sometimes, more) molecules of H2O. In addition, if the salts are microcrystalline or amorphous, they are potent adsorbents for H2O. In certain cases, they are even deliquescent under martian conditions. Finally, the high solubility of the vast majority of these salts (with notable exception of CaSO4) can result in dense brines with low water activity, aH, as well as cations which can be inimical to microbial metabolism, effectively "poisoning the well." The original geologic materials on Mars, igneous rocks, also provide some

  2. Aspectos clínicos e características do leite em ovelhas com mastite induzida experimentalmente com Staphylococcus aureus Clinical aspects and characteristics of the milk in sheep with mastitis experimentally induced with Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Rogério A. Santos


    and fat. The pH, the chlorates and CCS reached very high indexes, accompanied by the CMT test reaction. The bacteriological exam revealed the presence of S. aureus during the phase of infection. After the treatment of the sheep 36 hours PI, one animal came to death 48h PI, and the others showed clinical recovery; however there was no physiologic re-establishment of the inoculated udders which lost their function.

  3. Corrosión de tuberías

    Directory of Open Access Journals (Sweden)

    del Olmo, C.


    Full Text Available This paper deals with thé corrosion of pipes used in construction. General aspects of pipe corrosion are dealt with, without discussing either the kinetics or detailed phenomena of corrosion. General advise is given on practical measures to avoid as far as possible the development of corrosion, a problem which is both widespread and extremely expensive. The second part of the publication includes a questionnaire containing a number of points, whose ellaboration may serve as starting point for a systematic study on the most likely causes of pipe corrosion. A number of notes or comments are also added to each of the above points. Finally there is an appendix with tables, giving construction specifications data on permissible maxima for harmful ions applicable to mass or reinforced concrete for pipe construction (Law 2 987/1968, of 20-IX-68. This refers to sulphate and chlorate ions which normally may be present in Portland cement and concrete. It is emphasized that these contents should be kept low if the cement or concrete is going to be in contact with iron pipes.El presente trabajo aborda el tema de la corrosión de las tuberías empleadas en construcción. En él se enuncian unas consideraciones de carácter general sobre corrosión de tuberías, sin entrar ni en la cinética ni en los mecanismos propios de la corrosión, dándose a continuación unas recomendaciones de carácter práctico para evitar en lo posible este fenómeno tan generalizado y que tantas pérdidas ocasiona. En la segunda parte del trabajo se incluye un cuestionario que consta de una serie de puntos cuyo conocimiento puede servir de base para el comienzo de ima investigación sistemática sobre la causa o causas más probablemente determinantes de la corrosión de las tuberías. Complementan el cuestionario unas notas o comentarios a cada uno de los puntos tratados en el mismo. Por último se facilitan en un apéndice final unos cuadros orientativos del contenido m

  4. Oxidation of formic acid by oxyanions of chlorine and its implications to the Viking Labeled Release experiment (United States)

    Martinez, P.; Navarro-gonzalez, R.


    The Viking Landers that arrived on Mars in 1976 carried out three biological experiments designed to investigate if there was microbial life. These were the Gas-Exchange, Pyrolitic Release and Labeled Release experiments. The three experiments yielded positive responses but the Labeled Release experiment had a kinetic response indicative of microbial activity. The experiment consisted of adding a broth of nutrients (formic acid, glycolic acid, glycine, D- and L-alanine and D- and L-lactic acid uniformly marked with 14C) to martian soil samples. The results were surprising; the nutrients were consumed releasing radioactive gases in a manner that is compatible by terrestrial microorganisms. The existence of Martian life was contradicted by soil chemical analysis that indicated the absence of organic compounds above the detection limits of parts per billion (ppb). Instead the positive response of the Labeled Release Experiment was attributed to the existence of peroxides and/or superoxides in the Martian soils that destroyed the nutrients upon contact. Recently, the Phoenix mission that landed in the Martian Arctic in 2008 revealed the presence of a highly oxidized form of the element chlorine in the soil: perchlorate. Perchlorate is thought to have formed in the Martian atmosphere by the oxidation of chloride from volcanic sources with ozone. Therefore perchlorate is formed by the stepwise oxidation of hypochlorite, chlorite and chlorate. These oxyanions of chlorine are powerful oxidizers that may exist in the Martian soil and may have reacted with the nutrients of the Labeled Release Experiment. This paper aims to better understand these results by designing experiments to determine the kinetics of decomposition of formic acid to carbon dioxide with different oxidized forms of chlorine by headspace technique in gas chromatography coupled to mass spectrometry (GC / MS). Previous studies done in the laboratory showed that only hypochlorite quantitatively reacted with

  5. Development of sustainable Palladium-based catalysts for removal of persistent contaminants from drinking water (United States)

    Shuai, Danmeng

    Pd-based catalytic reduction has emerged as an advanced treatment technology for drinking water decontamination, and a suite of persistent contaminants including oxyanions, N-nitrosoamines, and halogenated compounds are amenable to catalytic reduction. The primary goal of this study is to develop novel Pd-based catalysts with enhanced performance (i.e., activity, selectivity, and sustainability) to remove contaminants from drinking water. The effects of water quality (i.e., co-contaminants in water matrix), catalyst support, and catalyst metal were explored, and they provide insights for preparing catalysts with faster kinetics, higher selectivity, and extended lifetime. Azo dyes are wide-spread contaminants, and they are potentially co-exisiting with target contaminants amenable for catalytic removal. The probe azo dye methyl orange (MO) enhanced catalytic reduction kinetics of a suite of oxyanions (i.e., nitrate, nitrite, bromate, chlorate, and perchlorate) and diatrizoate significantly but not N-nitrosodimethylamine (NDMA) with a variety of Pd-based catalysts. Nitrate was selected as a probe contaminant, and several different azo dyes (i.e., (methyl orange, methyl red, fast yellow AB, metanil yellow, acid orange 7, congo red, eriochrome black T, acid red 27, acid yellow 11, and acid yellow 17) were evaluated for their ability to enhance reduction. A hydrogen atom shuttling mechanism was proposed and a kinetic model was proposed based on Bronsted-Evans-Polanyi (BEP) theory, and they suggest sorbed azo dyes and reduced hydrazo dyes shuttle hydrogen atoms to oxyanions or diatrizoate to enhance their reduction kinetics. Next, vapor-grown carbon nanofiber (CNF) supports were used to explore the effects of Pd nanoparticle size and interior versus exterior loading on nitrite reduction activity and selectivity (i.e., dinitrogen over ammonia production). In order to evaluate the amount of interior versus exterior loading of Pd nanoparticles, a fast and accurate geometric

  6. 极谱法测定钼矿石中的总钼氧化钼硫化钼%Determination of Total Molybdenum, Molybdic Oxide and Molybdenum Sulfide in Molybdenum Ore by Polarography

    Institute of Scientific and Technical Information of China (English)



    Molybdenite is the major mineral in molybdenum ore. The phase analysis of molybdenum ore is required to determine sulfide minerals and oxide minerals. The phase analyses of molybdenum ores such as molybdenite, molybdite, powellite and molybdate galena were taken by photometry and Inductively Coupled Plasma-Atomic Emission Spectrometry ( ICP-AES). In this paper, the molybdenum ore sample was dissolved with aqua regia-sulfuric acid. The total molybdenum was extracted by alkali solution and the majority of the other elements were separated by precipitation. Molybdic oxides were leached by sodium carbonate and ammonium hydroxide solution. Molybdenum sulfides were obtained to dissolve residue. The contents of total molybdenum, molybdic oxide and molybdenum sulfide were determined by rapid polarography in a sulfuric acid-potassium chlorate-diphenyl glycollic acid system. The linear range of the method was 0. 04 -0. 4 mg/L, and the detection limit was 0. 028 mg/L. Three molybdenum ore samples were carried on phase analysis and the results were consistent with those obtained by photometry. The sum contents of molybdic oxide and molybdenum sulfide conformed to the total molybdenum content. RSDs (n=8) were 1.69% -3.56% for total molybdenum, molybdic oxide and molybdenum sulfide. This method was fast and suitable for practical batch samples.%钼的物相分析要求测定硫化矿物相和氧化矿物相,常用比色法和电感耦合等离子体发射光谱法等对辉钼矿、钼华矿、钼钨钙矿、钼酸铅矿等钼矿石进行物相分析,但分离物相的品种较多,方法繁琐耗时.本文用王水-硫酸消解钼矿石样品,碱溶液复溶浸提得到钼总量,使其他大多数元素形成沉淀而分离,用碳酸钠-氢氧化铵混合溶液浸取钼的氧化矿物,将残渣进一步溶解得到硫化矿物含量,在硫酸-氯酸钾-二苯羟乙酸体系中用极谱法简单快速测定钼总量、氧化钼和硫化钼含量.方法的线性范围为0.04~0

  7. Exposure assessment of a burning ground for chemical ammunition on the Great War battlefields of Verdun. (United States)

    Bausinger, Tobias; Bonnaire, Eric; Preuss, Johannes


    severe arsenic contamination and the transfer of this carcinogen by leachate, surface runoff and probably by wind. Nevertheless, some studies on the effects of the contaminant inventory on the local vegetation revealed that ammonium nitrate elutable zinc is responsible for the spatial distribution of some tolerant plant species and not arsenic. Previously undetected buried munitions from the former delaboration facility can be an other source of environmental contaminants. This is supported by elevated concentrations of chlorate (cmax.=71 mg/l) and perchlorate (cmax.=0.8 mg/l) detected in the leachate samples. This is the second report about environmental contamination related to post-war ammunition destruction activities along the 1914/18 Western Front.


    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Brown; Maohong Fan; Adrienne Cooper


    Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. Characterizations of dry PFS synthesized from SO{sub 2} show the PFS possesses amorphous structure, which is desired for it to be a good coagulant in water and wastewater treatment. A series of lab-scale experiments were conducted to evaluate the performance of PFS synthesized from waste sulfur dioxide, ferrous sulfate and sodium chlorate. The performance assessments were based on the comparison of PFS and other conventional and new coagulants for the removal of turbidity and arsenic under different laboratory coagulant conditions. Pilot plant studies were conducted at Des Moines Water Works in Iowa and at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, Georgia. PFS performances were compared with those of conventional coagulants. The tests in both water treatment plants have shown that PFS is, in general, comparable or better than other coagulants in removal of turbidity and organic substances. The corrosion behavior of polymeric ferric sulfate (PFS) prepared from SO{sub 2} and ferric chloride (FC) were compared. Results

  9. Research on the Oxidation Starch Preparation by Microwave Heating using New Oxidant and its Property%新型氧化剂微波干法制备氧化淀粉及其性能研究

    Institute of Scientific and Technical Information of China (English)

    彭佳莹; 周露; 杨椰; 钟耕


    Preparing modified starch by using dry method of microwave has been gradually promoted in China. It has some advantages such as short process, low energy consumption, easy to operate. The process of preparing oxidation starches by two oxidants; chlorine dioxide (to oxidation starch A) and sodium chlorate (to oxidation starch B) was investigated, and the characteristics of the modified starches were also discussed in this paper. The results on theprocess study showed that the oxidation reaction on starch could be caused by both oxidants using dry method of microwave heating. The carboxyl group content of oxidation starch A and oxidation starch B prepared by the method were (0.068 ±0.002)% and (0.586 ±0.002)% separately. The results on the properties of the modified starches showed that the thermal viscosity stability of the oxidation starch was improved and freeze - thaw stability of oxidation starch B was better. The release water rate of oxidation starch B was only 23.7% after freeze thawing twice. The alkali resistance of oxidation starch A was good, but not to the acid resistance. However, oxidation starch B showed a better alkali resistance and acid resistance. The oxidizing reaction to the modified starches happened in amorphous of the starch through X - ray diffraction. However, the crystal structure remains the same as the original starch.%干法制备变性淀粉已逐步在国内推广,它具有流程短,能耗低,操作简便等优点.采用微波干法工艺,研究了二氧化氯、氯酸钠两种氧化剂制备氧化淀粉(分别为氧化淀粉A和氧化淀粉B)的工艺和变性淀粉的性能.工艺研究表明,两种氧化剂均能通过微波干法制备氧化淀粉,而氧化淀粉A和氧化淀粉B的羧基含量分别为(0.068±0.002)%和(0.586±0.002)%.性能研究表明,氧化淀粉的热黏度稳定性得到了改善,氧化淀粉B的冻融稳定性较好,经2次冻融,析水率仅为23.7%;氧化淀粉A耐碱性能好,耐酸性较差,

  10. Application of preparation process of high pure chlorine dioxide by electrolysis method in water treatment%电解法制高纯二氧化氯工艺在水处理中的应用

    Institute of Scientific and Technical Information of China (English)

    刘艳霞; 韩瑞雄; 赵红; 周俊波


    为了开发经济实用的二氧化氯消毒工艺,对电解法制备高纯二氧化氯工艺在水处理中的运用进行了研究.在最佳条件下,电解氯酸盐自动催化循环制备的二氧化氯纯度可达98%左右.通过二氧化氯杀菌除藻试验,讨论了二氧化氯用量以及原水pH对细菌、叶绿素a、藻类的去除率的影响.结果表明,二氧化氯用量在2 mg/L以上时,3者的去除率均达到90%以上.当二氧化氯用量为2 mg/L、原水pH为6~9时,3者的去除率不发生显著变化,并且二氧化氯的剩余质量浓度均控制在0.5 mg/L以下.消毒成本:生产1 kg二氧化氯成本可以控制在6元以内,当二氧化氯用量在0.5 ~2 mg/L时,1 t水的消毒成本为0.003~ 0.012元.%To develop an economical and practical disinfection technology of chlorine dioxide, the application of preparation process of high pure chlorine dioxide by electrolysis method in water treatment was studied. Under the best conditions, the purity of chlorine dioxide, which was prepared by electrolysis of chlorate solution with auto-catalytic cycling,can reach about 98% . Through the experiments of algae removal and sterilization,the influences of concentration of chlorine dioxide and pH of raw water on the removal rate of bacteria,chlorophyll A ,and algal were discussed. Results showed that when the mass concentration of chlorine dioxide was above 2 mg/L, the removal rates of bacteria, chlorophyll A, and algal could all reached above 90% . When the mass concentration of chlorine dioxide was 2 mg/L and pH of raw water was at 6 ~9,the removal rates of them could not occur significant change, and the mass concentration of residual chlorine dioxide was all under 0. 5 mg/L. Though accounting for the cost of water disinfection, the cost of per kilogram chlorine dioxide in the process can be controlled less than RMB 6 Yuan. When the invested amount of chlorine dioxide was at 0.5 ~2 mg/L,and the cost of per ton water disinfection

  11. 利用糠醛废水生产环保融雪剂的工艺研究%Research on the Process of Producing Environmentally-friendly Snowmelt Agent with Furfural Water

    Institute of Scientific and Technical Information of China (English)

    赵国明; 于广军


    To protect environment and public facilities from damage of the pollution of furfural water and chlorate snowmelt agent, we come up with the new craft, which produce environmentally-friendly snowmelt agent-calcium magnesium acetate (CMA) from the acetic acid reaction of limestone, magnesium oxide and furfural water. First we make concentrate by double-effect evaporating neutralized furfural water, then produce calcium magnesium acetate in high concentration by adsorpting the concentrate with active carbon, and deliver the evaporated condensated water back to the furfural production, as a result the reusing of furfural water and zero discharge conies true. This article researches the process and parameters of producing environmentally-friendly snowmelt agent-calcium magnesium acetate with furfural water, which are based on experiments. The purity of the calcium magnesium acetate reached 92%, which well conforms to the quality specification of environmentally-friendly snowmelt agent. It accomplishes the efficient resources utilization of the furfural water by solving the bottleneck problem of non-environmentally-friendly producing the furfural, and lower the production cost by leaps aiid bounds. Finally the reusing of furfural water transfers from absolute investment to earning industry.%为解决目前糠醛废水产生的污染以及氯盐融雪剂对环境和公共设施造成的危害,提出采用新工艺,用石灰石、氧化镁等和糠醛塔底废水中的醋酸反应,直接制取环保型融雪剂醋酸钙镁(CMA)技术,并将中和后的废水经双效蒸发得到浓缩液,将浓缩液使用活性炭吸附得到纯度较高的醋酸钙镁,蒸发冷凝水回用糠醛生产,从而实现糠醛废水的资源化利用,达到污水的零排放.本论文通过实验研究确定利用糠醛废水生产环保融雪剂醋酸钙镁的工艺流程及参数,使生产的醋酸钙镁纯度达到92%,完全符合环保融雪剂的质量标准,既解决了制约糠醛

  12. Corrosión bajo tensión en aceros para pretensado

    Directory of Open Access Journals (Sweden)

    del Pozo, Florencio


    Full Text Available This paper summarises the first results of a testing program to investigate behaviour of prestressing steels in corrosion. This work is being done at the Central Laboratory for Testing Construction Materials, of the Centre of Research and Experiments of Public Works. The tests confirm the belief that patented drawn steels are very suitable for prestressing, and that the phenomenon of corrosion under stress must be infrequent in practice, if the work is well done. The most aggressive agents are those which provoke fragilization through hydrogen, the most frequent being SH2. Nitrates, which are often cited as typical corrosion agents associated to stress, are less dangerous than SH2. Tempered and case hardened steels are more susceptible to these attacks than cold drawn steels. Chlorates have turned out to be less dangerous than nitrates. After prolonged tests no failure has been recorded due to corrosion under stress. The purpose of this investigation is to develop a simple and representative test for the phenomenon of corrosion under stress and fragilization due to hydrogen, so that this test may complement the normal ones that are applied to classify steel.En este trabajo se resumen los primeros resultados de un plan de ensayos, para investigar el comportamiento frente a la corrosión de los aceros para pretensado, que está realizando el Laboratorio Central de Ensayo de Materiales de Construcción del Centro de Estudios y Experimentación de Obras Públicas. Los ensayos confirman el criterio de que los aceros patentados y trefilados reúnen buenas condiciones para su uso en pretensado y que el fenómeno de corrosión bajo tensión debe ser poco frecuente en la práctica, si la obra está bien realizada. Los agentes más agresivos son los que provocan fragilización por hidrógeno; el más frecuente es el SH2. Los nitratos, citados frecuentemente como agentes típicos de corrosión bajo tensión, son menos peligrosos que el SH2. Los aceros

  13. Preparation of disinfectant containing both chlorine dioxide and chlorine for safe urban reuse%复合二氧化氯的制备及其用于城市污水回用消毒

    Institute of Scientific and Technical Information of China (English)

    樊金红; 王红武; 马鲁铭


    在酸性环境中通过NaCl电解协同NaClO2化学氧化方法制备的复合二氧化氯溶液中ClO2和自由氯浓度分别达到70%和20%左右,系统地研究了电流密度(A)、NaClO2与NaCl质量比(B)、电解时间(C)对复合溶液中组分浓度和质量百分数的影响,并将复合溶液用于城市污水二级处理出水的消毒.结果表明,复合溶液中自由氯的浓度主要受因素C和A的影响,ClO2的浓度主要受因素C和B的影响,而A对副产物ClO-2和ClO-3的影响最大.总大肠菌群数在105~108个?L-1的城市污水二级处理出水采用复合溶液消毒时,当其中ClO2投加量为4mg? L-1,自由氯含量不低于1.20 mg?L-1,经30 min接触后出水生物学指标满足GB/T 18920-2002的要求.既降低了消毒剂的使用量,又减少了消毒副产物ClO-2的生成.%To achieve simultaneously maximum disinfection and minimum toxicity a mix disinfectant of chlorine dioxide and chlorine are found to be efficient for disinfection of drinking water and urban reused waste-water. However, transportation and reservation of the mixture may threat to environmental safety. Therefore, on-site preparation is necessary for field use. At present, preparation methods of the mix disinfectant have chemical reduction of sodium chlorate and electrolysis of sodium chloride, and the content of chlorine dioxide in mixture obtained is usually below 30%. To get high chlorine dioxide content, a method for the preparation of the mix disinfectant was proposed : electrolyzing sodium chloride (NaCl) was followed by a chemical oxidation of sodium chlorite (NaClC2) in an undivided electrolysis reactor, in which the content of C1O2 in the mix disinfectant can be controlled. The effect of current density (A), mass ratio of NaCIO2: NaCl (B), electrolysis time (C) on the concentration and mass percentage of CIO2, free chlorine, ClO-2 and C1O-3 was investigated systematically. Under the electrolysis conditions: current density 41. 67-83. 33 A

  14. Nickel Titanium Instrument with TF and Protaper for the Efficacy of Root Canal Therapy%机用镍钛器械TF和Protaper用于根管治疗的疗效观察

    Institute of Scientific and Technical Information of China (English)

    黄自理; 黄永坚


    Objective To machine nickel titanium mechanical TF and Protaper for the clinical curative ef ects of root canal therapy. Methods The hospital in 2013 May-12 months of Oral Department of internal medicine, 120 patients as the research object, the need for root canal treatment af ected teeth was 142, were randomly divided into observation group and control group each 71, observation group with dental nickel titanium files instruments in root canal preparation using TF machine, the control group teeth with nickel titanium files instruments in root canal preparation by Protaper. Two groups of patients after root canal preparation with sodium chlorate cleaning teeth, root canal is completely dry after use Calcium Hydroxide Paste, confirm the root canal does not affect the daily life of the patients with and 7 days is up, use warm gut a percha and AHplus root canal paste on root canal fil ing with vertical hot pressing method. Results In the observation group, 5 cases of overfil ing root exists, the control group had 10 cases of root tip there is a smal amount of overfil ing, no gut a percha beyond the apical foramen teeth, no charge less teeth occurred. The X light display, control group patients after root canal preparation, the root canal fluency is good, root canal morphology did not change, root canal preparation standard. Root canal preparation time of observation group was significantly shorter compared with the control group, and the P<0.05 has statistical significance. Conclusion TF machine used nickel titanium files instruments in root canal preparation time is shorter than Protaper, nickel titanium files instruments in root canal preparation is better than the Protaper TF machine.%目的:探讨机用镍钛机械TF和Protaper用于根管治疗的临床疗效。方法本次研究选取本院口腔内科2013年5月~12月的患者120例作为研究对象,其中需要进行根管治疗的患牙为142颗,随机分成观察组与对照组各71颗,观察组患牙