WorldWideScience

Sample records for bromates

  1. Remediation of bromate contaminated groundwater

    OpenAIRE

    Butler, R. M.

    2005-01-01

    Bromate (BrO3") is a by-product formed at concentrations of 0.4 - 60 µg L'' during potable water ozonation. Following World Health Organisation designation as a `possible human' carcinogen, a 10 pg L" drinking water limit was introduced in England and Wales. Discovery of bromate contamination within a UK aquifer highlighted a knowledge gap, addressed by this project, relating to environmental behaviour and groundwater remediation. Following selection of an anion analys...

  2. 21 CFR 172.730 - Potassium bromate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium bromate. 172.730 Section 172.730 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Specific Usage Additives § 172.730 Potassium bromate. The food additive potassium bromate may be...

  3. 21 CFR 137.205 - Bromated whole wheat flour.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Bromated whole wheat flour. 137.205 Section 137... Cereal Flours and Related Products § 137.205 Bromated whole wheat flour. Bromated whole wheat flour... of ingredients, prescribed for whole wheat flour by § 137.200, except that potassium bromate is...

  4. Bromate oxidized from bromide during sonolytic ozonation.

    Science.gov (United States)

    Lu, Ning; Wu, Xue-Fei; Zhou, Ji-Zhi; Huang, Xin; Ding, Guo-Ji

    2015-01-01

    Sonolytic ozonation (US/O3) is an effective way to degrade many pollutants in drinking water as the elevated mass transfer rate of ozone gas and the enhanced forming of hydroxyl radicals (OH). This work investigated the formation of bromate (BrO3(-)) from bromide (Br(-)) in sonolytic ozonation. At neutral pH, the bromate conversion rate ([BrO3(-)]/[Br(-)]0) was increased to 60% by ultrasound at continuous ozone flow (0-0.2Lmin(-1)), much higher than that without ultrasound or without bubbling. This indicates that the promoting effect of sonolysis on BrO3(-) formation is mainly due to the sonolytic decomposition of ozone and the enhancement of gas-liquid transfer. The [BrO3(-)]/[Br(-)]0 was increased with increasing pH. In addition, the reduction of HOBr/OBr(-) with ultrasound demonstrates that bromate may be inhibited as the bromide was formed with the H2O2 generation under ultrasound. This suggests the competition between bromate and bromide during the US/O3 led to the inhibition of bromate formation at high ozone flow. Therefore, our result reveals that the bromate formation under ultrasound is improved remarkably in US/O3 in quick treatment with proper ozone flow (<0.2Lmin(-1)). PMID:24931426

  5. Perturbation of bromate oscillators Pt. 1

    International Nuclear Information System (INIS)

    Reacting BZ systems of different catalysts [Ce3+, Mn2+, Fe(phen)32+, Ru(dipy)32+] have been perturbed by 60Co γ irradiation. At high bromate concentrations (between 0.15 and 0.1 molxdm-3) γ irradiation has no effect on the chemical oscillation irrespectively of the catalyst used. At lower bromate concentrations the oscillation is either quenched or considerably decreased in frequency in the case of cerium(III) or manganese(II). BZ systems with Fe(phen)32+ or Ru(dipy)32+ as a catalyst are not affected by γ irradiation. The major role of H atoms - produced in the radiolysis of water - is discussed, and the claim of other authors that the inhibitory effect can be attributed to bromide ions formed in the BrMA+H reaction is criticized. (author)

  6. STUDIES INTO THE MECHANISMS OF POTASSIUM BROMATE INDUCED THYROID CARCINOGENESIS

    Science.gov (United States)

    Studies into the Mechanisms of Potassium Bromate Induced Thyroid Carcinogenesis. Potassium bromate (KBrO3) occurs in finished drinking water as a by-product of the ozonation disinfection process and has been found to induce thyroid follicular cell tumors in the rat after ...

  7. Manganese porphyrin sensor for the determination of bromate.

    Science.gov (United States)

    Sheen, Shanty; Jos, Theresa; Rajith, Leena; Kumar, Krishnapillai Girish

    2016-03-01

    The electro reductive behavior and determination of bromate on [5, 10, 15, 20-tetrakis (4-methoxyphenylporphyrinato] Manganese (III) chloride (TMOPPMn(III)Cl) modified Gold electrode(GE) was investigated by Square wave voltammetry (SWV). Bromate showed an irreversible reduction peak at -164 mV in 0.1 M pH 7 Na2SO4 solution. The cathodic peak of bromate showed a reduction in potential of 88 mV on modifying GE with a porphyrin film. The peak current varied linearly with concentration with a detection limit of 3.56 × 10(-9) M. The influence of pH, scan rate, supporting electrolyte and interferents on the reduction peak current of bromate were studied. The developed sensor was proposed for the determination of bromate in bread samples and compared with the standard method. PMID:27570281

  8. Reduction of bromate to bromide coupled to acetate oxidation by anaerobic mixed microbial cultures.

    Science.gov (United States)

    van Ginkel, C G; van Haperen, A M; van der Togt, B

    2005-01-01

    Bromate, a weakly mutagenic oxidizing agent, exists in surface waters. The biodegradation of bromate was investigated by assessing the ability of mixed cultures of micro-organisms for utilization of bromate as electron acceptor and acetate as electron donor. Reduction of bromate was only observed at relatively low concentrations (sludge from an activated sludge treatment plant and a digester reduced bromate without lag period at a constant rate. Using an enrichment culture adapted to bromate, it was demonstrated that bromate was a terminal electron acceptor for anaerobic growth. Approximately 50% of the acetate was utilized for growth with bromate by the enrichment culture. A doubling of 20 h was estimated from a logarithmic growth curve. Other electron acceptors, like perchlorate, chlorate and nitrate, were not reduced or at negligible rates by bromate-utilizing microorganisms. PMID:15607164

  9. Retention studies on transiton metal bromates

    International Nuclear Information System (INIS)

    The retention of bromine in neutron activated nickel and zinc bromates was measured. Initial retentions for Ni(BrO3)2x6H2O and Zn(BrO3)2x6H2O were identical being 17, 19 and 30+-2% with respect to 80Br, sup(80m)Br and 82Br isotopes, respectively. Heat treatment at 110 deg C increased the retention (of 80Br) Oeyond 90% for the hydrated forms and just above 40% for the anhydrous forms of these systems. The activation energy involved was 2.56 and 0.31 eV for the hydrated and 0.49 and 0.34 eV for the anhydrous Ni and Zn bromates, respectively. Activation energy involved in the isothermal dehydration of Ni(BrO3)2x6H2O was 0.31 eV. Upon radiation treatment the optimum recovery in all the system was <10%. The relationship between isothermal annealing and dehydration is discussed. (author)

  10. Reduction of Bromate Formation During Ozonation of Drinking Water

    DEFF Research Database (Denmark)

    Antoniou, Maria; Sichel, C.; Andre, K.;

    This study focused on the prevention of carcinogenic bromate formation during ozonation of tap water from the DTU university campus. To achieve this, different pre-treatments including pH-adjustment, ammonia addition and chlorine-ammonia addition, were tested. Formation of bromated was drastically...... reduced by each pretreatment while the required ozone dose for 90% atrazine removal increased at different degree for each pre-treatment....

  11. Characterization of bromate-reducing bacterial isolates and their potential for drinking water treatment.

    Science.gov (United States)

    Davidson, Andrew N; Chee-Sanford, Joanne; Lai, Hoi Yi Mandy; Ho, Chi-hua; Klenzendorf, J Brandon; Kirisits, Mary Jo

    2011-11-15

    The objective of the current study was to isolate and characterize several bromate-reducing bacteria and to examine their potential for bioaugmentation to a drinking water treatment process. Fifteen bromate-reducing bacteria were isolated from three sources. According to 16S rRNA gene sequencing, the bromate-reducing bacteria are phylogenetically diverse, representing the Actinobacteria, Bacteroidetes, Firmicutes, and α-, β-, and γ-Proteobacteria. The broad diversity of bromate-reducing bacteria suggests the widespread capability for microbial bromate reduction. While the cometabolism of bromate via nitrate reductase and (per)chlorate reductase has been postulated, five of our bromate-reducing isolates were unable to reduce nitrate or perchlorate. This suggests that a bromate-specific reduction pathway might exist in some microorganisms. Bioaugmentation of activated carbon filters with eight of the bromate-reducing isolates did not significantly decrease start-up time or increase bromate removal as compared to control filters. To optimize bromate reduction in a biological drinking water treatment process, the predominant mechanism of bromate reduction (i.e., cometabolic or respiratory) needs to be assessed so that appropriate measures can be taken to improve bromate removal. PMID:21943884

  12. [Improved sensitive determination method for bromate in bread].

    Science.gov (United States)

    Kawasaki, Yoko; Kubota, Hiroki; Yomota, Chikako; Maitani, Tamio

    2002-08-01

    An effective clean-up procedure was developed to determine trace levels of bromate in bread by high-performance liquid chromatography with post-column flow reactor detection. Bromate was extracted from bread with deionized pure water. After centrifugation, the supernatant was filtered through a paper filter. The filtrate was filtered through a 0.2 micron nylon filter and chloride ion was removed by an IC-SP M Ag cartridge column or On-Guard Ag cartridge column. The eluate was applied to an Oasis MAX anion exchange cartridge column. The column was washed with 20% acetic acid and water. Bromate was then eluted with 0.5% sodium nitrate solution. The eluate was determined by HPLC with post column flow reactor detection. The method had a quantitation limit of 2 ng/g in bread products. Recoveries of bromate from bread ranged from 68 to 72% at a spiked bromate level of 2-10 ng/g. PMID:12436714

  13. A new electrochemical oscillatory system of bromate in alkaline solution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new electrochemical oscillatory system of bromate in alkaline solution is reported. In PtBromate-Alkaline solution system, two different types of electrochemical oscillations (Type Ⅰ and Type Ⅱ) can be observed. Type Ⅰ appears before hydrogen evolution and Type Ⅱ involves periodic hydrogen evolution. Type Ⅰ relates to the adsorption/desorption of the hydrogen on platinum electrode, and Type Ⅱ with periodic oscillation stems from the coupling of electrochemical reactions (the reduction of bromate and evolution hydrogen reaction) with mass transfer (diffusion and convection). More over, under the right conditions, the two types appear in different oscillatory modes, for example,simple periodical mode and mixed one, etc,, Crossed cycle in the cyclic voltammograms, which is the basiccharacteristics for electrochemical oscillatory systems, has also been observed as expected.

  14. Chemical oscillations in the 4-aminophenol bromate photoreaction

    Science.gov (United States)

    Harati, Mohammad; Amiralaei, Sheida; Green, James; Wang, Jichang

    2007-05-01

    Chemical oscillations have been uncovered in the photo-mediated 4-aminophenol-bromate reaction. The presence of light is found essential both to the extent of the reaction and the oscillatory behavior, where turning-off (on) the light results in an immediate disappearance (revival) of the oscillation. The long induction time in this photochemical oscillator shows an exponential dependence on the light intensity. Phase diagrams show that illumination with intense light allows the otherwise non-oscillatory system to exhibit oscillations over broad 4-aminophenol, bromate and sulfuric acid concentrations. Preliminary mechanistic studies suggest that the reaction involves the production of N-bromo-1,4-benzoquinone-4-imine.

  15. Molecular biomarkers of oxidative stress associated with bromate carcinogenicity

    International Nuclear Information System (INIS)

    Potassium bromate (KBrO3) is a chemical oxidizing agent found in drinking water as a disinfection byproduct of surface water ozonation. Chronic exposures to KBrO3 cause renal cell tumors in rats, hamsters and mice and thyroid and testicular mesothelial tumors in rats. Experimental evidence indicates that bromate mediates toxicological effects via the induction of oxidative stress. To investigate the contribution of oxidative stress in KBrO3-induced cancer, male F344 rats were administered KBrO3 in their drinking water at multiple concentrations for 2-100 weeks. Gene expression analyses were performed on kidney, thyroid and mesothelial cell RNA. Families of mRNA transcripts differentially expressed with respect to bromate treatment included multiple cancer, cell death, ion transport and oxidative stress genes. Multiple glutathione metabolism genes were up-regulated in kidney following carcinogenic (400 mg/L) but not non-carcinogenic (20 mg/L) bromate exposures. 8-Oxodeoxyguanosine glycosylase (Ogg1) mRNA was up-regulated in response to bromate treatment in kidney but not thyroid. A dramatic decrease in global gene expression changes was observed following 1 mg/L compared to 20 mg/L bromate exposures. In a separate study oxygen-18 (18O) labeled KBrO3 was administered to male rats by oral gavage and tissues were analyzed for 18O deposition. Tissue enrichment of 18O was observed at 5 and 24 h post-KBr18O3 exposure with the highest enrichment occurring in the liver followed by the kidney, thyroid and testes. The kidney dose response observed was biphasic showing similar statistical increases in 18O deposition between 0.25 and 50 mg/L (equivalent dose) KBr18O3 followed by a much greater increase above 50 mg/L. These results suggest that carcinogenic doses of potassium bromate require attainment of a threshold at which oxidation of tissues occurs and that gene expression profiles may be predictive of these physiological changes in renal homeostasis

  16. Kinetic and Equilibrium Studies for the Removal of Bromate by the Modified Activated Carbon

    Directory of Open Access Journals (Sweden)

    Muqing Qiu

    2015-03-01

    Full Text Available Bromate which was formed bromide dissolved in water during the ozonation process, is carcinogenic and mutagenic to humans. To avoid bromate damage, many countries strictly control its concentration in drinking water. Activated carbon is an effective adsorbent material widely used in water treatment. In order to enhance the adsorption of bromate ion on activated carbon, the modified activated carbon was obtained from granular activated carbon by chemical activation using cationic surfactant as an activator. The adsorption characteristics of bromate ion on the modified activated carbon were investigated through adsorption experiments. The effects of temperature, pH in solution, contact time and initial bromate concentration on bromate adsorption by the modified activated carbon were investigated. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Kinetic adsorption data were analyzed by the pseudo-first-order kinetic model and the pseudo-second-order model, respectively.

  17. Kinetic and Equilibrium Studies for the Removal of Bromate by the Modified Activated Carbon

    OpenAIRE

    Muqing Qiu; Shuiying Xiong

    2015-01-01

    Bromate which was formed bromide dissolved in water during the ozonation process, is carcinogenic and mutagenic to humans. To avoid bromate damage, many countries strictly control its concentration in drinking water. Activated carbon is an effective adsorbent material widely used in water treatment. In order to enhance the adsorption of bromate ion on activated carbon, the modified activated carbon was obtained from granular activated carbon by chemical activation using cationic surfactant as...

  18. Bromate formation from bromide oxidation by the UV/persulfate process.

    Science.gov (United States)

    Fang, Jing-Yun; Shang, Chii

    2012-08-21

    Bromate formation from bromide oxidation by the UV/persulfate process was investigated, along with changes in pH, persulfate dosages, and bromide concentrations in ultrapure water and in bromide-spiked real water. In general, the bromate formation increased with increasing persulfate dosage and bromide concentration. The bromate formation was initiated and primarily driven by sulfate radicals (SO(4)(•-)) and involved the formation of hypobromous acid/hypobromite (HOBr/OBr(-)) as an intermediate and bromate as the final product. Under the test conditions, the rate of the first step driven by SO(4)(•-) is slower than that of the second step. Direct UV photolysis of HOBr/OBr(-) to form bromate and the photolysis of bromate are insignificant. The bromate formation was similar for pH 4-7 but decreased over 90% with increasing pH from 7 to above 9. Less bromate was formed in the real water sample than in ultrapure water, which was primarily attributable to the presence of natural organic matter that reacts with bromine atoms, HOBr/OBr(-) and SO(4)(•-). The extent of bromate formation and degradation of micropollutants are nevertheless coupled processes unless intermediate bromine species are consumed by NOM in real water. PMID:22831804

  19. The perturbation of bromate oscillators by γ-irradiation

    International Nuclear Information System (INIS)

    Reacting Belousov-Zhabotinskij (BZ) systems of different catalysts have been perturbed by 60Co γ-irradiation. At high bromate concentrations, above 0.1 mol.dm-3, γ-irradiation has no effect on the chemical oscillation irrespectively of the catalyst used. At lower bromate concentrations the oscillation is either quenched or considerably decreased in frequency in the case of cerium(III) or manganese(II). BZ systems with Fe(phen)32+ or Ru(dipy)32+ as a catalyst are not affected by γ-irradiation. The major role of H-atoms - produced in the radiolysis of water - is discussed, and the claim of earlier authors that the inhibitory effect can be attributed to bromide ions formed in the BrMA + H reaction is criticized. (author)

  20. Control of Bromate and THM Precursors Using Ozonation Combined System

    Institute of Scientific and Technical Information of China (English)

    SHU-GUANG XIE; DONG-WEN SHI; DONG-HUI WEN; RUI WANG; DAN-LI XI

    2007-01-01

    Objective To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. Methods The appropriate ozone dosage was determined,and then the changes of TOC,UV254 and THM formation potential(THMFP)in the combined system were evaluated. Results One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water.The pre-ozonation increased THMFP,but the conventional treatment system could effectively reduce the odor.The bio-ceramic filter could partly reduce CHCI3FP,but sometimes might increase CHCI2BrFP and CHCIBr2FP.The biological activated carbon(BAC)filter could effectively reduce CHCI3FP and CHCI2BrFP,but increase CHCIBr2FP.Compared with other filters.the fresh activated carbon(FAC)filter performed better in reducing THMFP and even reduced CHCIBrzFP.Conclusion The combined system can effectively reduce taste,odor,CHCI3FP,and CHCI2BrFP and also bring bromate under control.

  1. Pilot study on bromate reduction in ozonation of water with low carbonate alkalinities by carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Ji Li; Li Zou; Lulu Guo; Jialin Ji

    2011-01-01

    A pilot study was carried out to explore the application of carbon dioxide for pH depression in a bubble column and its ability to inhibit bromate formation for water with a low alkalinity.Results showed that in the absence of ammonia,CO2 was capable of reducing bromate 38.0%-65.4% with one-unit pH depression.CO2 caused a slightly lower bromate reduction (4.2%) than did H2SO4 when the pH was depressed to 7.4,and a more a pronounced lower reduction (8.8%) when the pH was depressed to 6.9.In the presence of 0.20mg/L-N ammonia,bromate was largely inhibited with 73.9% reduction.When the pH was depressed to 7.4,CO2 and H2SO4 showed an 11.3% and 23.5% bromate reduction respectively,demonstrating that the joint use of CO2 and ammonia might be a plausible strategy of blocking all three bromate formation pathways.CO2 could be applied through the aeration diffuser together with ozone gas,resulting in a similar bromate reduction compared with the premixing method through Venturi mixer.

  2. NMR study of 23Na shielding tensor in sodium bromate single crystal

    International Nuclear Information System (INIS)

    NMR-investigations of sodium bromate showed that the electronic shielding of the 23Na nucleus is anisotropic. The effect is qualitatively explained by the deformation of electronic shells of the Na+ ion

  3. Room temperature phosphorimetric determination of bromate in flour based on energy transfer.

    Science.gov (United States)

    Menendez-Miranda, Mario; Fernandez-Argüelles, Maria T; Costa-Fernandez, Jose M; Pereiro, Rosario; Sanz-Medel, Alfredo

    2013-11-15

    Determination of bromate ions in contaminated flour samples by using a room temperature phosphorescence (RTP) optosensor is described. The optosensor is based on the non-radiative energy transfer from α-bromonaphthalene (a phosphorescent molecule insensitive to the presence of the analyte) acting as donor, to an energy acceptor bromate-sensitive molecule (trifluoperazine hydrochloride). The RTP emission of the selected donor greatly overlaps with the absorption spectrum of the acceptor, resulting in a decrease of the measured signal as the concentration of bromate ions increases. A simple and general procedure is proposed to carry out the incorporation of both the donor and acceptor molecules in an appropriate solid material (sensing phase) through the co-immobilization of the species in a sol-gel inorganic matrix. The optimum amounts of the sol-gel precursors, including silica precursors, type of catalysis, and concentrations of donor and acceptor molecules, have been evaluated in order to obtain the best analytical features of the proposed optosensor for bromate determination. The highly stable developed sensing phase shows a selective and reversible response towards bromate even in presence of dissolved oxygen (a well-known quencher of the RTP). The calibration graphs were linear up to 200 mg L(-1), with a detection limit for bromate dissolved in aqueous medium of 0.2 mg L(-1). Sample throughput of the proposed optosensor was about 18 measurements h(-1). Application of the developed sensing phase was successfully proved for the detection of bromate ions in commercial flours, obtaining good recoveries. PMID:24148398

  4. The kinetics of bromate-cerium(III) and -iron(II) reactions

    International Nuclear Information System (INIS)

    The bromate-cerium(III) and -iron(II) reactions in acidic media were examined with special reference to their induction periods and reaction rates. In the bromate-cerium(III)reaction, the induction period is followed by a burst of cerium (IV) formation and then a gradual formation of cerium(IV). In the bromate-iron(II) reaction, a slow decrease occurs only in acidic media, even without bromate, so it may differ from the decrease in the tris(1, 10-phenanthroline)iron(II) concentration based on the oxidation by bromate. Itwas interpreted as the dissociation from ( Fe(phen)3 ) 2+ to ( Fe(phen)2 ) 2+ and phen. This is the induction period for iron(III) formation, which follows as the burst. The induction period and the rates of cerium(IV) or iron(III) formation can be interpreted on the basis of the mechanism for the Belousov oscillatory and the present redox reactions proposed by Noyes and his co-workers. (author)

  5. Novel pre-treatments to control bromate formation during ozonation

    DEFF Research Database (Denmark)

    Antoniou, Maria; Sichel, Cosima; Andre, Klaus;

    2016-01-01

    Worldwide water shortage increase and water quality depletion from microbial and chemical compounds, pose significant challenges for today’s water treatment industry. Both the development of new advanced oxidation technologies, but also the enhancement of existing conventional technologies...... is of high interest. This study tested improvements to conventional ozonation that reduce the formation of the oxidation-by-product bromate, while maintaining the effectiveness for removal emerging contaminants (atrazine). MnO4−, ClO2−, ClO2, ClO−, CH3COOO−, HSO5− or S2O8−2 with NH4+ were tested as pre......-treatments to ozonation of ground water. Each oxidant and NH4+ were added in a single stage or separately prior to ozonation. To the best of our knowledge, this is the first study that has tested all the above-mentioned oxidants for the same water matrix. Based on our results, the most promising pre-treatments were MnO4...

  6. Measurement of bromate in bread by liquid chromatography with post-column flow reactor detection.

    Science.gov (United States)

    Himata, K; Noda, M; Ando, S; Yamada, Y

    2000-01-01

    This method is suitable for the determination of bromate residues in a variety of baked goods. The peer-verified method trial was performed on white bread, multigrain bread, and coffee cake spiked with known levels of potassium bromate. The analytical portion is extracted with deionized water to remove bromate from the bulk of the baked product. The aqueous extract is carried through a series of steps to remove co-extractives that would interfere with the liquid chromatography (LC) in the determinative step or hasten the deterioration of the LC column. The extract is filtered before passing it through a reversed-phase solid-phase extraction (SPE) column and a cation-exchange column in the silver form to remove lipids and chloride, respectively. Ultrafiltration is then used to remove proteins with molecular weights of >30,000 daltons. Finally, a cation-exchange column in the sodium form is used to remove silver ions from the extract. The determinative step uses LC with a reversed-phase column and an ion-pairing agent in the mobile phase. Detection is based on the post-column reaction of bromate with o-dianisidine to form an oxidation product that is quantitated spectrophotometrically at 450 nm. Overall agreement between the submitting and peer laboratories was quite good. For bromate levels of 10-52 ppb, overall mean recoveries were 76.9 and 78.8% for the submitting and peer laboratories, respectively. The standard deviations were higher for the results of the peer laboratory, probably because of the generally higher level of baseline noise present in the chromatograms. The results demonstrate that the method provides adequate accuracy with low-fat as well as high-fat foods. Bromate at levels as low as 5 ppb (ng/g) can be detected with the method. PMID:10772172

  7. Selenium dioxide catalysed oxidation of acetic acid hydrazide by bromate in aqueous hydrochloric acid medium

    Indian Academy of Sciences (India)

    R S Yalgudre; G S Gokavi

    2012-07-01

    Selenium dioxide catalysed acetic acid hydrazide oxidation by bromate was studied in hydrochloric acid medium. The order in oxidant concentration, substrate and catalyst were found to be unity. Increasing hydrogen ion concentration increases the rate of the reaction due to protonation equilibria of the oxidant. The mechanism of the reaction involves prior complex formation between the catalyst and substrate, hydrazide, followed by its oxidation by diprotonated bromate in a slow step. Acetic acid was found to be the oxidation product. Other kinetic data like effect of solvent polarity and ionic strength on the reaction support the proposed mechanism.

  8. Fe(II)–Al(III) layered double hydroxides prepared by ultrasound-assisted co-precipitation method for the reduction of bromate

    International Nuclear Information System (INIS)

    Highlights: ► Fe(II)–Al(III) LDHs were synthesized by ultrasound-assisted co-precipitation method. ► The Fe–Al (30 min) exhibited highly reduction reactivity on bromate. ► Pseudo-first-order model described the experimental data well. ► The mechanisms of bromate removal were proposed. -- Abstract: Bromate is recognized as an oxyhalide disinfection byproduct in drinking water. In this paper, Fe(II)–Al(III) layered double hydroxides (Fe–Al LDHs) prepared by the ultrasound-assisted co-precipitation method were used for the reduction of bromate in solution. The Fe–Al LDHs particles were characterized by X-ray diffractometer, scanning electron microscopy and thermogravimetry–differential scanning calorimetry. It was found that ultrasound irradiation assistance promoted the formation of the hydrotalcite-like phase and then improved the removal efficiency of bromate. In addition, the effects of solid-to-solution ratio, contact time, initial bromate concentration, initial pH, coexisting anions on the bromate removal were investigated. The results showed the bromate with an initial concentration of 1.56 μmol/L could be completely removed from solution by Fe–Al LDHs within 120 min. When the initial bromate concentration was 7.81 μmol/L, the Fe–Al LDHs with irradiation time of 30 min exhibited the optimum removal efficiency and the bromate removal capacity (qe) was 6.80 μmol/g. In addition, the appearance of sulfate and production of bromide were observed simultaneously in this process, which suggested that ion-exchange between sulfate and bromate, and the reduction of bromate to bromide by Fe2+ were the main mechanisms responsible for the bromate removal by Fe–Al LDHs

  9. Fe(II)–Al(III) layered double hydroxides prepared by ultrasound-assisted co-precipitation method for the reduction of bromate

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yu [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Yang, Qi, E-mail: yangqi@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Luo, Kun; Wu, Xiuqiong [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Li, Xiaoming, E-mail: xmli@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Liu, Yang [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Urban and Rural Garbage Disposal Technology Research Center, Hunan Province, Changsha 410082 (China); Tang, Wangwang; Zeng, Guangming; Peng, Bo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2013-04-15

    Highlights: ► Fe(II)–Al(III) LDHs were synthesized by ultrasound-assisted co-precipitation method. ► The Fe–Al (30 min) exhibited highly reduction reactivity on bromate. ► Pseudo-first-order model described the experimental data well. ► The mechanisms of bromate removal were proposed. -- Abstract: Bromate is recognized as an oxyhalide disinfection byproduct in drinking water. In this paper, Fe(II)–Al(III) layered double hydroxides (Fe–Al LDHs) prepared by the ultrasound-assisted co-precipitation method were used for the reduction of bromate in solution. The Fe–Al LDHs particles were characterized by X-ray diffractometer, scanning electron microscopy and thermogravimetry–differential scanning calorimetry. It was found that ultrasound irradiation assistance promoted the formation of the hydrotalcite-like phase and then improved the removal efficiency of bromate. In addition, the effects of solid-to-solution ratio, contact time, initial bromate concentration, initial pH, coexisting anions on the bromate removal were investigated. The results showed the bromate with an initial concentration of 1.56 μmol/L could be completely removed from solution by Fe–Al LDHs within 120 min. When the initial bromate concentration was 7.81 μmol/L, the Fe–Al LDHs with irradiation time of 30 min exhibited the optimum removal efficiency and the bromate removal capacity (q{sub e}) was 6.80 μmol/g. In addition, the appearance of sulfate and production of bromide were observed simultaneously in this process, which suggested that ion-exchange between sulfate and bromate, and the reduction of bromate to bromide by Fe{sup 2+} were the main mechanisms responsible for the bromate removal by Fe–Al LDHs.

  10. Characterization of bromate-reducing bacterial isolates and their potential for drinking water treatment

    Science.gov (United States)

    The objective of the current study was to isolate and characterize several bromatereducing bacteria and to examine their potential for bioaugmentation to a drinking water treatment process. Fifteen bromate-reducing bacteria were isolated from three sources. According to 16S rRNA gene sequencing, the...

  11. Study On Adsorption of Bromate From Aqueous Solution On Modified Activated Carbon

    Science.gov (United States)

    Liu, Tong-mian; Cui, Fu-yi; Zhao, Zhi-wei; Liu, Dong-mei; Zhu, Qi; Wang, Huan

    2010-11-01

    A coal-based activated carbon was treated chemically with nitric acid, sodium hydroxide and ammonia for its surface modification, and its adsorption capacity was investigated with bromate. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pHpzc and Boehm titration. The results indicated that the specific surface area of the activated carbon decreased after oxidation with nitric acid. But the amount of surface acidic oxygen-containing functional groups of the oxidized sample increased compared to the raw carbon and the points of zero charge (pHpzc) decreased. The specific surface area of the activated carbon also decreased after sodium hydroxide treatment and the points of zero charge increased. The changes of surface chemical properties after the ammonia treatment was opposite to the oxidized sample. As a result, the pHpzc of the carbon was increased to near pH9.3, the amount of surface basic groups was increased. Furthermore, the data of bromate adsorption on all the samples were fitted to the Langmuir isotherm model well which indicates monolayer adsorption. In addition, the adsorption capacity of ammonia treatment sample was the highest and its saturated adsorption capacity reached 1.55 mg/g. A strong correlation was found between basic groups and adsorption capacity of bromate. Enhancement of basic groups was favorable for bromate removal.

  12. CONSUMER WILLINGNESS TO PAY FOR SAFETY LABELS IN NIGERIA: A CASE STUDY OF POTASSIUM BROMATE IN BREAD

    Directory of Open Access Journals (Sweden)

    O Oni

    2006-05-01

    Full Text Available The study analysed consumer willingness to pay for safety labels in Nigeria by a case study of potassium bromate in bread” in Benin City, Edo State. It specifi cally investigates factors that promote willingness to pay for label among consumers of bread in Benin City, Edo State. Data used for the study were obtained through a well-structured questionnaire from 200 respondents. Both descriptive analytical methods and probit regression models were used for the analysis. The study revealed that 73% of the respondents are in their active working age with 50 percent of the respondent being male and female respectively. 67 percent of the respondents are married with 55 percent having an average of 5 members per household. 99 percent of the respondents are educated i.e. they have the capability of being able to read and write. Respondents purchased bread mainly from hawkers (60% with about 60% of them being aware of the presence of bromate in bread. 40% of the consumers used labeling as a way of identifying bromate free bread. Other methods reported deal with differences in price of bread with same weight, aroma and taste. Result also revealed that 60% of the respondents got to know about the negative effect of bromate from news (both print and mass media. Econometric results show that variables like education, gender, income, prior knowledge of bromate and perception held by respondents of negative implications of bromate signifi cantly infl uence the willingness to pay for safety labels. Education, gender, income and prior knowledge of bromate positively infl uence the probability of consumers’ decision to pay for safety label, while price of bread and confi dence and perception held by respondents of negative implications of bromate on human health infl uence consumers willingness to pay more for safety labels. The study, thus, suggests a defi ned market for bread purchases, community based awareness programme and extension of National Agency

  13. Research strategy for developing key information on bromate's mode of action

    International Nuclear Information System (INIS)

    Bromate is produced when ozone is used to treat waters that contain trace amounts of bromide ion. It is also a contaminant of hypochlorite solutions produced by electrolysis of salt that contains bromide. Both ozone and hypochlorite are extensively used to disinfect drinking water, a process that is credited with reducing the incidence of waterborne infections diseases around the world. In studies on experimental animals, bromate has been consistently demonstrated to induce cancer, although there is evidence of substantial species differences in sensitivity (rat > mouse > hamster). There are no data to indicate bromate is carcinogenic in humans. An issue that is critical to the continued use of ozone as a disinfectant for drinking water in bromide-containing waters depends heavily on whether current predictions of carcinogenic risk based on carcinogenic responses in male rats treated with bromate are accurate at the much lower exposure levels of humans. Thiol-dependent oxidative damage to guanine in DNA is a plausible mode of action for bromate-induced cancer. However, other mechanisms may contribute to the response, including the accumulation of α2u-globulin in the kidney of the male rat. To provide direction to institutions that have an interest in clarifying the toxicological risks that bromate in drinking water might pose, a workshop funded by the Awwa Research Foundation was convened to lay out a research strategy that, if implemented, could clarify this important public health issue. The technical issues that underlie the deliberations of the workshop are provided in a series of technical papers. The present manuscript summarizes the conclusions of the workgroup with respect to the type and timing of research that should be conducted. The research approach is outlined in four distinct phases that lay out alternative directions as the research plan is implemented. Phase I is designed to quantify pre-systemic degradation, absorption, distribution, and

  14. Etiology of bromate-induced cancer and possible modes of action-studies in Japan

    International Nuclear Information System (INIS)

    Renal cell tumors were significantly increased in male and female rats given potassium bromate at 250 and 500 mg/L in drinking water. In at least one other study renal cell tumors were produced in male rats at 125 mg/L. Among male mice given 750 mg/L of potassium bromate, there were no significant differences in renal cell tumors between treated and control groups after 88 weeks on test. In oxidative DNA damage tests 8-oxodeoxyguanosine (8-oxodG also referred to as 8-OH-dG) was induced in DNA in the male rat kidney in 1 week, and in females after 3 weeks at 500 mg/L, and also in both male and female rats at 250 mg/L, but not at 125 mg/L. DNA adducts are considered to be an initial step in the carcinogenesis process, however, the administered doses are not always sufficient to cause mutations, possibly due to DNA repair. In the two-step rat renal carcinogenesis model using N-ethyl-N-hydroxyethylnitrosamine (EHEN) as initiator, promotion activity by potassium bromate was measured using the BrdU labeling index. The promoting activity of bromate in male rats was much greater and extended to doses as low as 60 mg/L in male rats, whereas in females the response was limited to 250 and 500 mg/L. Therefore, it was concluded that the mechanisms contributing to cancer in the male rat were more complex than in the female rat. The accumulation of α2μ-globulin in the kidneys of male rats exposed to potassium bromate probably accounts for the greater labeling index in the male rat relative to the female rat. Accumulation of α2μ-globulin as a result of treatment with chemicals is unique to the male rat and does contribute to carcinogenic responses. Neither humans nor female rats display this response. Nevertheless, bromate must be considered carcinogenic because of the response of the female rats. The better correlation between 8-oxodG formation and tumor response indicates that dose-response information from the female rat would be much more relevant to human risk assessment

  15. Advanced oxidation of bromide-containing drinking water: a balance between bromate and trihalomethane formation control.

    Science.gov (United States)

    Wang, Yongjing; Yu, Jianwei; Han, Po; Sha, Jing; An, Tao; Li, Wei; Liu, Juan; Yang, Min

    2013-11-01

    Addition of H202 has been employed to repress bromate formation during ozonation of bromide-containing source water. However, the addition of H2O2 will change the oxidation pathways of organic compounds due to the generation of abundant hydroxyl radicals, which could affect the removal efficacy of trihalomethane precursors via the combination of ozone and biological activated carbon (O3-BAC). In this study, we evaluated the effects of H2O2 addition on bromate formation and trihalomethane formation potential (THMFP) reduction during treatment of bromide-containing (97.6-129.1 microg/L) source water by the O3-BAC process. At an ozone dose of 4.2 mg/L, an H2O2/O3 (g/g) ratio of over 1.0 was required to maintain the bromate concentration below 10.0 microg/L, while a much lower H2O2/O3 ratio was sufficient for a lower ozone dose. An H2O2/O3 (g/g) ratio below 0.3 should be avoided since the bromate concentration will increase with increasing H2O2 dose below this ratio. However, the addition of H202 at an ozone dose of 3.2 mg/L and an H2O2/O3 ratio of 1.0 resulted in a 43% decrease in THMFP removal when comparedwith the O3-BAC process. The optimum H2O2/O3 (g/g) ratio for balancing bromate and trihalomethane control was about 0.7-1.0. Fractionation of organic materials showed that the addition of H2O2 decreased the removal efficacy of the hydrophilic matter fraction of DOC by ozonation and increased the reactivity of the hydrophobic fractions during formation of trihalomethane, which may be the two main reasons responsible for the decrease in THMFP reduction efficacy. Overall, this study clearly demonstrated that it is necessary to balance bromate reduction and THMFP control when adopting an H2O2 addition strategy. PMID:24552044

  16. Cetyltrimethylammonium-coated magnetic nanoparticles for the extraction of bromate, followed by its spectrophotometric determination

    International Nuclear Information System (INIS)

    We report on a combination of magnetic solid-phase extraction and spectrophotometric determination of bromate. Cetyltrimethylammonium ion was adsorbed on the surface of phenyl-functionalized silica-coated Fe3O4 nanoparticles (Ph-SiO2-Fe3O4), and these materials served as the sorbent. The effects of surfactant and amount of sorbent, the composition of the desorption solution, the extraction time and temperature were optimized. Under optimized conditions, an enrichment factor of 12 was achieved, and the relative standard deviation is 2.9 % (for n = 5). The calibration plot covers the 1–50 ng mL−1 range with reasonable linearity (r2 > 0.998); and the limit of detection is 0.5 ng mL−1. The method is not interfered by ionic compounds commonly found in environmental water samples. It was successfully applied to the determination of bromate in spiked water samples. (author)

  17. Application of Silver and Silver Oxide Nanoparticles Impregnated on Activated Carbon to the Degradation of Bromate.

    Science.gov (United States)

    Choi, J S; Lee, H; Park, Y K; Kim, S J; Kim, B J; An, K H; Kim, B H; Jung, S C

    2016-05-01

    Silver and silver oxide nanoparticles were impregnated on the surface of powdered activated carbon (PAC) using a single-step liquid phase plasma (LPP) method. Spherical silver and silver oxide nanoparticles of 20 to 100 nm size were dipersed evenly on the surface of PAC. The impregnated PAC exhibited a higher activity for the decomposition of bromate than bare PAC. The XPS, Raman and EDX analyses showed that the Ag/PAC composites synthesized by the LPP process. PMID:27483780

  18. Complete bromate and nitrate reduction using hydrogen as the sole electron donor in a rotating biofilm-electrode reactor.

    Science.gov (United States)

    Zhong, Yu; Li, Xin; Yang, Qi; Wang, Dongbo; Yao, Fubing; Li, Xiaoming; Zhao, Jianwei; Xu, Qiuxiang; Zhang, Chang; Zeng, Guangming

    2016-04-15

    Simultaneous reduction of bromate and nitrate was investigated using a rotating biofilm-electrode reactor (RBER) with graphite carbon (GC) rods as anode and activated carbon fiber (ACF) bonded with steel ring as cathode. In RBER, the community of denitrifying bacteria immobilized on the cathode surface could completely utilize hydrogen (H2) as the electron donor, which was internally produced by the electrolysis of water. The short-term test confirmed that the RBER system could reduce 150-800μg/L bromate to below 10μg/L under autotrophic conditions. The reduced bromate was considered to be roughly equivalent to the amount of bromide in effluent, indicating that bromate was completely reduced to bromide without accumulation of by-products. The long-term test (over 120 days) showed that the removal fluxes of bromate and nitrate could be improved by increasing the electric current and decreasing the hydraulic retention time (HRT). But nitrite in effluent was significantly accumulated when the electric current was beyond 10mA and the HRT was less than 6h. The maximum bromate reduction rate estimated by the Monod equation was 109.12μg/Lh when the electric current was 10mA and HRT was 12h. It was proposed that the electron transfer process in RBER produced H2 on the surface of the ACF cathode, and the microbial cultures attached closely on the cathode which could completely utilize H2 as electron donors for reduction of bromate and nitrate. PMID:26775102

  19. Titrimetric and spectrophotometric determination of doxycycline hyclate using bromate-bromide, methyl orange and indigo carmine

    Directory of Open Access Journals (Sweden)

    Pavagada Jagannathamurthy Ramesh

    2010-07-01

    Full Text Available One titrimetric and two indirect spectrophotometric methods are described for the determination of doxycycline hyclate (DCH in bulk drug and in its formulations. The methods use bromate-bromide, methyl orange and indigo carmine as reagents. In titrimetry (method A, DCH is treated with a known excess of bromate- -bromide mixture in acid medium and the residual bromine is back titrated iodometrically after the reaction between DCH and in situ bromine is ensured to be complete. In spectrophotometric methods, the excess of bromine is estimated by treating with a fixed amount of either methyl orange (method B or indigo carmine (method C and measuring the change in absorbance either at 520 or 610 nm. Titrimetric method is applicable over 1-8 mg range and the calculations are based on a 1:2 (DCH:bromate stoichiometric ratio. In spectrophotometry, the calibration graphs were found to be linear over 0.25-1.25 and 1.0-5.0 μg mL-1 for method B and C, respectively, with corresponding molar absorptivity values of 2.62×105 and 6.97×104 L mol-1 cm-1. The accuracy and precision of the assays were determined by computing the intra-day and inter-day variations at three different levels of DCH.

  20. Ruthenium catalyst on carbon nanofiber support layers for use in silicon-based structured microreactors, Part II: Catalytic reduction of bromate contaminants in aqueous phase

    NARCIS (Netherlands)

    Thakur, D.B.; Tiggelaar, R.M.; Weber, Y.; Gardeniers, J.G.E.; Lefferts, L.; Seshan, K.

    2011-01-01

    Catalyst layers were synthesized inside a structured channel of silicon based microreactor and used to remove bromate contaminants in water. It is demonstrated that Ru/CNF based catalyst is active for bromate reduction, resulting in turn over frequencies (TOFs) higher than conventional powdered cata

  1. Electrochemical fabrication of copper-containing metal-organic framework films as amperometric detectors for bromate determination.

    Science.gov (United States)

    Shi, Erbin; Zou, Xiaoqin; Liu, Jia; Lin, Huiming; Zhang, Feng; Shi, Shaoxuan; Liu, Fenghua; Zhu, Guangshan; Qu, Fengyu

    2016-05-01

    A facile electrochemical plating strategy has been employed to prepare the electroactive metal-organic framework film (NENU-3) onto a copper electrode in the acid electrolyte containing 1,3,5-benzenetricarboxylic acid (H3BTC) and phosphotungstic acid (PTA). The as-made NENU-3 films have been characterized using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analyses (TGA). These analyses indicate that NENU-3 films have high phase purity and high stability. Further, different electrochemical techniques are utilized for measuring the electrochemical behaviors of the NENU-3 film electrodes. Accordingly, the kinetic parameters of a NENU-3 film electrode towards the electrocatalytic reduction of bromate are obtained, including the electron transfer coefficient (α), the catalytic rate constant (ks), and the diffusion coefficient (D). The film electrodes present excellent electrocatalytic ability for the bromate reduction, and can be used successfully for the amperometric detection of bromate. Under the optimized conditions, the proposed sensor exhibits a wide linear range (0.05-72.74 mM) and a lower detection limit (12 μM) measured by chronoamperometry (CA). Moreover, the films possess high electrochemical stability and strong anti-interference capability in the bromate detection process. It has been demonstrated that the electrochemical plating method reported here offers a reliable and efficient way to fabricate MOF films on conductive substrates for bromate detection. PMID:27054956

  2. Formation of bromate during ferrate(VI) oxidation of bromide in water.

    Science.gov (United States)

    Huang, Xin; Deng, Yang; Liu, Shuang; Song, Yali; Li, Nanzhu; Zhou, Jizhi

    2016-07-01

    Ferrate (VI) is traditionally recognized as a safe oxidant without production of disinfection byproducts (DBPs). However, here we detected probable carcinogenic bromate (BrO3(-)) during ferrate(VI) oxidation of bromide (Br(-))-containing water, and evaluated the effects of pH, ferrate(VI) dose, initial Br(-) concentration, and co-existing anions on the BrO3(-) formation. BrO3(-) was produced at a moderately-weakly acidic pH condition and in the absence of phosphate that was commonly applied as a buffer and stabilizing agent in previous ferrate(VI) studies. At pH 5.0, the produced BrO3(-) was increased from 12.5 to 273.8 μg/L with the increasing initial Br(-) concentration from 200 to 1000 μg/L at 10 mg/L Fe(VI), corresponding to an increase in the molar conversion ([BrO3(-)]/initial [Br(-)]) from 2.3% to 10.3%, in a bicarbonate-buffered solution. As pH increased to 7.0, the BrO3(-) concentration gradually dropped. The BrO3(-) production appeared to be associated with the oxidation by high valence iron species (i.e. Fe(VI), Fe(V) and Fe(IV)). Two key intermediate products (i.e. hypobromous acid/hypobromite (HOBr/OBr(-)) and hydrogen peroxide (H2O2)) relevant to the bromate formation were identified. The production of HOBr, a requisite intermediate for the ensuing bromate formation, was indirectly validated through identification of bromine-containing trihalomethanes and haloacetic acids during ferrate oxidation in a natural water, though these bromo-organic DBPs produced were insignificant. Furthermore, the inhibition effects of various anions on the formation of BrO3(-) followed chloride H2O2 was detected at higher phosphate concentration. It could reduce HOBr to Br(-), thereby inhibiting the bromate formation. PMID:27153235

  3. Surface studies on as-grown (111) faces of sodium bromate crystals

    Indian Academy of Sciences (India)

    K Kishan Rao; V Surender

    2001-12-01

    Single crystals of sodium bromate are grown at various supersaturations ranging from 3% to 8%. Surface studies have been carried out on as-grown and etched (111) faces of these crystals. Typical and systematically oriented growth hillocks are observed almost on all the faces. Further dislocation studies are made to understand the growth history of these crystals. These studies suggest that the crystals grow by 2D-growth mechanism. In addition to this, studies are also conducted on the formation of overgrowths and inclusions in these crystals.

  4. Conversion of organic micropollutants with limited bromate formation during the Peroxone process in drinking water treatment

    OpenAIRE

    Knol, A.H.; Lekkerkerker-Teunissen, K.; C. J. Houtman; Scheideler, J.; Ried, A.; Van Dijk, J. C.

    2015-01-01

    Advanced oxidation with O3/H2O2 (peroxone) is conducted on pilot plant scale on pre-treated Meuse river water to investigate the conversion of organic micropollutants (OMPs) and the formation of bromate. Fourteen selected model compounds are dosed to the pre-treated river water on a regular basis to assess the efficiency of the peroxone process and to establish the influence of the water matrix. The height of the ozone dose is the main factor in the conversion of t...

  5. Chlorination of bromide-containing waters: Enhanced bromate formation in the presence ofsynthetic metal oxides and deposits formed indrinking water distribution systems

    KAUST Repository

    Liu, Chao

    2013-09-01

    Bromate formation from the reaction between chlorine and bromide in homogeneous solution is a slow process. The present study investigated metal oxides enhanced bromate formation during chlorination of bromide-containing waters. Selected metal oxides enhanced the decay of hypobromous acid (HOBr), a requisite intermediate during the oxidation of bromide to bromate, via (i) disproportionation to bromate in the presence of nickel oxide (NiO) and cupric oxide (CuO), (ii) oxidation of a metal to a higher valence state in the presence of cuprous oxide (Cu2O) and (iii) oxygen formation by NiO and CuO. Goethite (α-FeOOH) did not enhance either of these pathways. Non-charged species of metal oxides seem to be responsible for the catalytic disproportionation which shows its highest rate in the pH range near the pKa of HOBr. Due to the ability to catalyze HOBr disproportionation, bromate was formed during chlorination of bromide-containing waters in the presence of CuO and NiO, whereas no bromate was detected in the presence of Cu2O and α-FeOOH for analogous conditions. The inhibition ability of coexisting anions on bromate formation at pH 8.6 follows the sequence of phosphate>>sulfate>bicarbonate/carbonate. A black deposit in a water pipe harvested from a drinking water distribution system exerted significant residual oxidant decay and bromate formation during chlorination of bromide-containing waters. Energy dispersive spectroscopy (EDS) analyses showed that the black deposit contained copper (14%, atomic percentage) and nickel (1.8%, atomic percentage). Cupric oxide was further confirmed by X-ray diffraction (XRD). These results indicate that bromate formation may be of concern during chlorination of bromide-containing waters in distribution systems containing CuO and/or NiO. © 2013 Elsevier Ltd.

  6. Addition of hydrogen peroxide for the simultaneous control of bromate and odor during advanced drinking water treatment using ozone.

    Science.gov (United States)

    Wang, Yongjing; Yu, Jianwei; Zhang, Dong; Yang, Min

    2014-03-01

    Complete removal of the characteristic septic/swampy odor from Huangpu River source water could only be achieved under an ozone dose as high as 4.0 mg/L in an ozone-biological activated carbon (O3-BAC) process, which would lead to the production of high concentrations of carcinogenic bromate due to the high bromide content. This study investigated the possibility of simultaneous control of bromate and the septic/swampy odor by adding H2O2 prior to the O3-BAC process for the treatment of Huangpu River water. H2O2 addition could reduce the bromate concentration effectively at an H2O2/O3 (g/g) ratio of 0.5 or higher. At the same time, the septic/swampy odor removal was enhanced by the addition of H2O2, although optimization of the H2O2/O3 ratio was required for each ozone dose. At an ozone dose of 2.0 mg/L, the odor was removed completely at an H2O2/O3 ratio of 0.5. The results indicated that H2O2 application at a suitable dose could enhance the removal of the septic/swampy odor while suppressing the formation of bromate during ozonation of Huangpu River source water. PMID:25079267

  7. Role of γ-irradiation on the induction period of the thermal decomposition of doped barium bromate

    International Nuclear Information System (INIS)

    The thermal decomposition of pure as well as γ-irradiated doped (Al3+) barium bromate has been studied between 543 to 563K and is seen that irradiation shortens the induction period, I, conforming to the relation I=C1.C2 log θ. The experimental and the theoretical values for the induction period are well agreeable. (author). 10 refs

  8. Mixed mode and sequential oscillations in the cerium-bromate-4-aminophenol photoreaction

    Science.gov (United States)

    Bell, Jeffrey G.; Wang, Jichang

    2013-09-01

    Cerium was introduced to the bromate-aminophenol photochemical oscillator to implement coupled autocatalytic feedbacks. Mixed mode and sequential oscillations emerged in the studied system, making it one of the few chemical oscillators known to support consecutive bifurcations in a batch system. The complex reaction behavior showed a strong dependence on the intensity of illumination supplied to the system. Removal of illumination during an oscillatory window affected both the frequency and amplitude of the oscillation but did not fully extinguish them, indicating that the cerium-bromate-4-aminophenol oscillator was photosensitive rather than photo-controlled. A moderate light intensity allowed for a slow evolution of the system, which proved to be critical for the emergence of transient complex oscillations. Variation of individual reaction parameters was carried out, which indicated that the development of complex oscillations occur in a narrow region and a phase diagram in the 4-aminophenol and sulfuric acid plane demonstrated this. Simulations provide strong support that transient complex oscillations observed experimentally arise from the coupling of two autocatalytic cycles.

  9. Mixed mode and sequential oscillations in the cerium-bromate-4-aminophenol photoreaction

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Jeffrey G.; Wang Jichang [Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2013-09-15

    Cerium was introduced to the bromate-aminophenol photochemical oscillator to implement coupled autocatalytic feedbacks. Mixed mode and sequential oscillations emerged in the studied system, making it one of the few chemical oscillators known to support consecutive bifurcations in a batch system. The complex reaction behavior showed a strong dependence on the intensity of illumination supplied to the system. Removal of illumination during an oscillatory window affected both the frequency and amplitude of the oscillation but did not fully extinguish them, indicating that the cerium-bromate-4-aminophenol oscillator was photosensitive rather than photo-controlled. A moderate light intensity allowed for a slow evolution of the system, which proved to be critical for the emergence of transient complex oscillations. Variation of individual reaction parameters was carried out, which indicated that the development of complex oscillations occur in a narrow region and a phase diagram in the 4-aminophenol and sulfuric acid plane demonstrated this. Simulations provide strong support that transient complex oscillations observed experimentally arise from the coupling of two autocatalytic cycles.

  10. Mixed mode and sequential oscillations in the cerium-bromate-4-aminophenol photoreaction

    International Nuclear Information System (INIS)

    Cerium was introduced to the bromate-aminophenol photochemical oscillator to implement coupled autocatalytic feedbacks. Mixed mode and sequential oscillations emerged in the studied system, making it one of the few chemical oscillators known to support consecutive bifurcations in a batch system. The complex reaction behavior showed a strong dependence on the intensity of illumination supplied to the system. Removal of illumination during an oscillatory window affected both the frequency and amplitude of the oscillation but did not fully extinguish them, indicating that the cerium-bromate-4-aminophenol oscillator was photosensitive rather than photo-controlled. A moderate light intensity allowed for a slow evolution of the system, which proved to be critical for the emergence of transient complex oscillations. Variation of individual reaction parameters was carried out, which indicated that the development of complex oscillations occur in a narrow region and a phase diagram in the 4-aminophenol and sulfuric acid plane demonstrated this. Simulations provide strong support that transient complex oscillations observed experimentally arise from the coupling of two autocatalytic cycles

  11. Effect of crystal transformation on 80Br retention in cadmium bromate

    International Nuclear Information System (INIS)

    Both the hydrated and anhydrous forms of cadmium bromate yield 15, 18 and 20 +- 1% initial retention of 80Br, sup(80m)Br and 82Br respectively. On heating at 1250C for 1 h the 80Br retention remains lower by approx. 20% than the identical values (approx. 50%) for sup(80m)Br and 82Br isotopes. The rate and the extent of annealing of the 80Br species during heat and radiation treatments are greater in the hydrated form and are further enhanced when structural rearrangement occurs following dehydration at 1250C. The associated activation energy is 0.09 eV below this temperature while it is 0.40 eV above, the latter value being identical with the activation energy for the dehydration process. (orig.)

  12. Chemiluminescence determination of potassium bromate in flour based on flow injection analysis.

    Science.gov (United States)

    Yan, Zhengyu; Zhang, Zhengwei; Yu, Yan; Liu, Zhen; Chen, Jianqiu

    2016-01-01

    A novel and highly sensitive flow-injection chemiluminescence method for the determination of potassium bromate (KBrO3) has been developed. This method is based on the luminescence properties of the KBrO3-Na2SO3-quinine sulfate system in acid medium. Optimized experimental conditions and a possible mechanism were investigated. The relative chemiluminescence intensity responded linearly to the concentration of KBrO3 in the range of 7.054 × 10(-6)-1.008 × 10(-4) mol/L with a detection limit of 2.116 × 10(-6) mol/L. The relative standard deviation (RSD) at 5.0 × 10(-5) mol/L KBrO3 (n = 12) was 2.3%. The proposed method was applied successfully to the determination of KBrO3 in flour. PMID:26212936

  13. EFFECTS OF POTASSIUM BROMATE ON THE KIDNEY AND HAEMATOLOGICAL PARAMETERS OF SWISS ALBINO MICE

    Directory of Open Access Journals (Sweden)

    MARIA STUTI

    2013-01-01

    Full Text Available The present study aimed to investigate the possible effects of potassium bromate toxicity on histological,haematological and biochemical parameters in Swiss albino mice. Mice were orally administered with potassiumbromate at the rate of 150 mg/kg body weight daily in a single dose for 30, 60 and 120 days. The chemicalsignificantly reduced the RBC count (p<0.01 Hb% (p<0.01 and platelet count (p<0.01, while it increasedsignificantly the urea (p<0.01 and creatinine level (p<0.01 and decreased total protein and Albumin (p<0.01Histopathological examination showed degenerative changes of tubular cells, cytoplasma vacuolation, cellularinfiltration, tubular dilation with eosinophilic debris and clear cell cytoplasm were observed. These findingssuggest that KBrO3 affects the physiological and biochemical activities of Swiss albino mice

  14. Catalytic effects of trace ruthenium on oxidation of dimethyl yellow with bromate and its application

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhi-rong; WANG Qun; ZHANG Shu-yuan

    2008-01-01

    A spectrophotometric method for the determination of ruthenium(Ⅲ) is described, based on its catalytic effect on the oxidation reaction of dimethyl yellow (DMY) with potassium bromate in an acid solution medium and in the presence of an OP emulsifier (p-iso-octyl phenoxy polyethoxy ethanol) at 100 ℃. This reaction was followed spectrophotometrically by measuring the decrease in the absorbance at 530 nm of the catalytic reaction of DMY. The calibration curve for the recommended method was linear in the concentration range over 0.0-1.0 μg/Land the detection limit of the method for Ru(Ⅲ) was 0.01 μg/L. The method is highly sensitive, selective and very stable and has been successfully applied for the determination of trace amounts of ruthenium in some ores and metallurgy products with the relative standard deviations (RSD) over 1.6%-2.8% and a recovery over 98.7%-104.0%.

  15. A sensitive amperometric bromate sensor based on multi-walled carbon nanotubes/phosphomolybdic acid composite film

    International Nuclear Information System (INIS)

    An amperometric sensor for bromate was developed based on multi-walled carbon nanotubes (MWNTs)/phosphomolybdic acid (PMo12) composite film coated on a pyrolytic graphite (PG) electrode. MWNTs are dispersed in PMo12 aqueous solution through spontaneous and strong chemisorption between carbon and polyoxometalate, which results in a homogeneous MWNTs/PMo12 composite. Due to the unique electronic and electrocatalytic properties of MWNTs and PMo12, the combination of MWNTs and PMo12 results in a remarkable synergistic augmentation on the response current. The bromate sensor based on the PG/MWNTs/PMo12 electrode has excellent characteristics, such as a detection limit of 0.5 μM, a sensitivity of 760.9 μA mM-1 cm-2, a response time less than 2 s and a linear range from 5 μM to 15 mM

  16. Spectrophotometric reaction rate method for determination of barbituric acid by inhibition of the hydrochloric acid-bromate reaction

    Science.gov (United States)

    Ensafi, Ali A.; Movahedinia, H.

    2003-11-01

    A new kinetic-spectrophotometric method was developed for the determination of barbituric acid. The method is based on its inhibition effect on the reaction between hydrochloric acid and bromate. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 510 nm. The variable affecting the rate of the reaction was investigated. The method is simple, rapid, relatively sensitive and precise. The limit of detection is 7.9×10 -7 M and calibration rang is 1×10 -6-6.0×10 -4 M barbituric acid. The linearity range of the calibration graph is depends on bromate concentration. The relative standard deviation of seven replication determination of 5.6×10 -6 M barbituric acid was 1.8%. The influence of potential interfering substance was studied.

  17. Association of brominated proteins and changes in protein expression in the rat kidney with subcarcinogenic to carcinogenic doses of bromate

    International Nuclear Information System (INIS)

    The water disinfection byproduct bromate (BrO3−) produces cytotoxic and carcinogenic effects in rat kidneys. Our previous studies demonstrated that BrO3− caused sex-dependent differences in renal gene and protein expression in rats and the elimination of brominated organic carbon in their urine. The present study examined changes in renal cell apoptosis and protein expression in male and female F344 rats treated with BrO3− and associated these changes with accumulation of 3-bromotyrosine (3-BT)-modified proteins. Rats were treated with 0, 11.5, 46 and 308 mg/L BrO3− in drinking water for 28 days and renal sections were prepared and examined for apoptosis (TUNEL-staining), 8-oxo-deoxyguanosine (8-oxoG), 3-BT, osteopontin, Kim-1, clusterin, and p-21 expression. TUNEL-staining in renal proximal tubules increased in a dose-related manner beginning at 11.5 mg BrO3−/L in female rats and 46 mg/L in males. Increased 8-oxoG staining was observed at doses as low as 46 mg/L. Osteopontin expression also increased in a dose-related manner after treatment with 46 mg/L, in males only. In contrast, Kim-1 expression increased in a dose-related manner in both sexes, although to a greater extent in females at the highest dose. Clusterin and p21 expression also increased in a dose-related manner in both sexes. The expression of 3-BT-modified proteins only increased in male rats, following a pattern previously reported for accumulation of α-2u-globulin. Increases in apoptosis in renal proximal tubules of male and female rats at the lowest doses suggest a common mode of action for renal carcinogenesis for the two sexes that is independent of α-2u-globulin nephropathy. - Highlights: • Bromate induced nephrotoxicity in both male and female rats by similar mechanisms. • Apoptosis was seen in both male and female rats at the lowest doses tested. • Bromate-induced apoptosis correlated to 8-oxo-deoxyguanosine formation. • Bromate increased the level of 3-bromotyrosine

  18. Association of brominated proteins and changes in protein expression in the rat kidney with subcarcinogenic to carcinogenic doses of bromate

    Energy Technology Data Exchange (ETDEWEB)

    Kolisetty, Narendrababu [Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602 (United States); Bull, Richard J. [MoBull Consulting, Richland, WA 99352 (United States); Muralidhara, Srinivasa; Costyn, Leah J. [Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602 (United States); Delker, Don A. [School of Medicine, University of Utah, Salt Lake City, UT 84132 (United States); Guo, Zhongxian [Water Quality Office, Public Utilities Board, 608576 (Singapore); Cotruvo, Joseph A. [Joseph Cotruvo and Associates, LLC, Washington, DC 20016 (United States); Fisher, Jeffrey W. [National Center for Toxicological Research, FDA, Jefferson, AR 72079 (United States); Cummings, Brian S., E-mail: bsc@rx.uga.edu [Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602 (United States)

    2013-10-15

    The water disinfection byproduct bromate (BrO{sub 3}{sup −}) produces cytotoxic and carcinogenic effects in rat kidneys. Our previous studies demonstrated that BrO{sub 3}{sup −} caused sex-dependent differences in renal gene and protein expression in rats and the elimination of brominated organic carbon in their urine. The present study examined changes in renal cell apoptosis and protein expression in male and female F344 rats treated with BrO{sub 3}{sup −} and associated these changes with accumulation of 3-bromotyrosine (3-BT)-modified proteins. Rats were treated with 0, 11.5, 46 and 308 mg/L BrO{sub 3}{sup −} in drinking water for 28 days and renal sections were prepared and examined for apoptosis (TUNEL-staining), 8-oxo-deoxyguanosine (8-oxoG), 3-BT, osteopontin, Kim-1, clusterin, and p-21 expression. TUNEL-staining in renal proximal tubules increased in a dose-related manner beginning at 11.5 mg BrO{sub 3}{sup −}/L in female rats and 46 mg/L in males. Increased 8-oxoG staining was observed at doses as low as 46 mg/L. Osteopontin expression also increased in a dose-related manner after treatment with 46 mg/L, in males only. In contrast, Kim-1 expression increased in a dose-related manner in both sexes, although to a greater extent in females at the highest dose. Clusterin and p21 expression also increased in a dose-related manner in both sexes. The expression of 3-BT-modified proteins only increased in male rats, following a pattern previously reported for accumulation of α-2{sub u}-globulin. Increases in apoptosis in renal proximal tubules of male and female rats at the lowest doses suggest a common mode of action for renal carcinogenesis for the two sexes that is independent of α-2{sub u}-globulin nephropathy. - Highlights: • Bromate induced nephrotoxicity in both male and female rats by similar mechanisms. • Apoptosis was seen in both male and female rats at the lowest doses tested. • Bromate-induced apoptosis correlated to 8-oxo

  19. Stability of penta- and hexavalent americium in the solutions of sodium peroxydisulfate and sodium bromate at intensive internal α-irradiation

    International Nuclear Information System (INIS)

    The spectrometric method has been used for studying the dependence of the rates of radiolytic reduction of Am(5) and (6) on the initial concentration of sodium persulfate and bromate, Am(5) and (6), acidity, and the dose rate of inner alpha-irradiation of the solutions. The high dose rates of inner alpha-irradiation of solutions (up to 3.25x1021 eV/lxmin-250Ci/l) have been attained with the aid of curium isotopes. The stability of americium (6) ions towards the action of ionizing radiation in solutions of sodium persulfate and bromate has been shown to be considerable lower than that of americium (5). The chemical difference has been shown in radiolytic behaviour between Am(5) and Am(6) ions in solutions of sodium persulfate and bromate. The equations have been derived showing the dependence of the rates of Am(6) and Am(5) reduction of different variables

  20. Bromate Removal from Water Using Doped Iron Nanoparticles on Multiwalled Carbon Nanotubes (CNTS

    Directory of Open Access Journals (Sweden)

    Aasem Zeino

    2014-01-01

    Full Text Available The raw carbon nanotubes (CNTs were prepared by the floating catalyst chemical vapor deposition method. The raw carbon nanotubes were functionalized, impregnated with iron nanoparticles, and characterized using high resolution transmission electron microscopy (HRTEM, scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS, Fourier transform infrared spectroscopy (FTIR, Differential Scanning Calorimetry (DSC, and thermogravimetric analysis (TGA. The three types of these multiwalled carbon nanotubes were applied as adsorbents for the removal of bromate from drinking water. The effects of the pH, the concentration of BrO3- anion, the adsorbent dose, the contact time, and the coanions on the adsorption process have been investigated. The results concluded that the highest adsorption capacities were 0.3460 and 0.3220 mg/g through using CNTs-Fe and raw CNTs, respectively, at the same conditions. The results showed that the CNTs-Fe gives higher adsorption capacity compared with the raw CNTs and the functionalized CNTs. The presence of nitrate (NO3- in the solution decreases the adsorption capacity of all CNTs compared with chloride (Cl- associated with pH adjustment caused by nitric acid or hydrochloric acid, respectively. However, the adsorption of all MWNCTs types increases as the pH of solution decreases.

  1. Behavior of sup(80m)Br in potassium bromate crystals

    International Nuclear Information System (INIS)

    A study was made about the chemical changes caused by isomeric transition of sup(80m)Br to sup(80)Br potassium bromate crystals marked with sup(80m)Br and the thermic annealing reactions of the isomeric transition products. Once the isomeric transition has been completed, transition associated with the emission of internal conversion electrons and Auger processes, the chemical analysis of the system which is being studied shows a change in the atom or ion due to the nuclear transformation. The described chemical changes can be reverted if the compound which contains the transformed atomic nucleus is heated before the chemical analysis is performed. Such a process was called annealing reaction and generally conduces to an increase of the retention considered as the percentage of radioactive atoms which reappear in the original chemical form after the nuclear transformation of a reliable technique which will permit the quantitative separation of the chemical fractions produced during the nuclear transformation of the metastable isomer, with the purpose to evaluate the percentage of the produced chemical change as well as the retention. The establishment of this technique was reached. (author)

  2. Impact of potassium bromate and potassium iodate in a pound cake system.

    Science.gov (United States)

    Wilderjans, Edith; Lagrain, Bert; Brijs, Kristof; Delcour, Jan A

    2010-05-26

    This study investigates the impact of the oxidants potassium bromate and potassium iodate (8, 16, 32, 64, and 128 micromol/g dry matter of egg white protein) on pound cake making. The impact of the oxidants on egg white characteristics was studied in a model system. Differential scanning calorimetry showed that the oxidants caused egg white to denature later. During heating in a rapid visco analyzer, the oxidants caused the free sulfhydryl (SH) group levels to decrease more intensively and over a smaller temperature range. The oxidants made the proteins more resistant to decreases in protein extractability in sodium dodecyl sulfate containing buffer during cake recipe mixing and less resistant to such decreases during cake baking. We assume that, during baking, the degree to which SH/disulfide exchange and SH oxidation can occur depends on the properties of the protein at the onset of the process. In our view, the prevention of extractability loss during mixing increased the availability of SH groups and caused more such loss during baking. During cooling, all cakes baked with added oxidants showed less collapse. On the basis of the presented data, we put forward that only those protein reactions that occur during baking contribute to the formation of a network that supports final cake structure and prevents collapse. PMID:20423045

  3. Determination of vanadium(5) and 8-hydroxyquinoline by oxidation of aniline with bromate ions in highly acidic solutions using spectrometry and thermal lensing

    International Nuclear Information System (INIS)

    When studying the rate of aniline oxidation by bromate-ions depending on the medium pH, it was revealed that pH reduction resulted in the change in characteristics of the reaction products absorption band. Physicochemical characteristics of the reaction considered occurring in highly acid medium (pH 2.4) were determined: pseudoorders in terms of oxidizing and reducing agents and effective rate constants. It is shown that aniline oxidation by bromate-ions in a highly acid medium permits reducing detection limits of vanadium(5) and 8-hydroxyquinoline (as activator of vanadium catalytic activity) both for spectrophotometric and thermal lensing detection

  4. Oral administration of potassium bromate induces neurobehavioral changes, alters cerebral neurotransmitters level and impairs brain tissue of swiss mice

    OpenAIRE

    Ajarem, Jamaan; Altoom, Naif G; Allam, Ahmed A.; Maodaa, Saleh N.; Abdel- Maksoud, Mostafa A.; Chow, Billy KC.

    2016-01-01

    Background Potassium bromate (KBrO3) is widely used as a food additive and is a major water disinfection by-product. The present study reports the side effects of KBrO3 administration on the brain functions and behaviour of albino mice. Methods Animals were divided into three groups: control, low dose KBrO3 (100 mg/kg/day) and high dose KBrO3 (200 mg/kg/day) groups. Results Administration of KBrO3 led to a significant change in the body weight in the animals of the high dose group in the firs...

  5. Phosphomolybdate-doped-poly(3,4-ethylenedioxythiophene) coated gold nanoparticles: Synthesis, characterization and electrocatalytic reduction of bromate

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Syeda Sara [School of Chemistry, Monash University, VIC 3800 (Australia); National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Liu, Yuping [School of Chemistry, Monash University, VIC 3800 (Australia); Sirajuddin,; Solangi, Amber Rehana [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Bond, Alan M., E-mail: alan.bond@monash.edu [School of Chemistry, Monash University, VIC 3800 (Australia); Zhang, Jie, E-mail: jie.zhang@monash.edu [School of Chemistry, Monash University, VIC 3800 (Australia)

    2013-11-25

    Graphical abstract: -- Highlights: •Stable and water soluble phosphomolybdate-doped-PEDOT coated gold nanoparticles were synthesized. •Electrodes modified with these nanoparticles show well defined voltammetric response and excellent stability in acidic media. •These nanocomposite catalysts exhibit an excellent catalytic activity towards electroreduction of bromate. -- Abstract: Phosphomolybdate, H{sub 3}PMo{sub 12}O{sub 40}, (PMo{sub 12})-doped-poly(3,4-ethylenedioxythiophene) (PEDOT) coated gold nanoparticles have been synthesized in aqueous solution by reduction of AuCl{sub 4}{sup −} using hydroxymethyl EDOT as a reducing agent in the presence of polystyrene sulfonate and PMo{sub 12}. The resulting PMo{sub 12}-doped-PEDOT stabilized Au nanoparticles are water soluble and have been characterized by UV–visible spectroscopy, scanning electron microscopy and electrochemistry. Glassy carbon electrodes modified with these Au nanoparticles show excellent stability and catalytic activity towards the reduction of bromate in an aqueous electrolyte solution containing 10 mM H{sub 2}SO{sub 4} and 0.1 M Na{sub 2}SO{sub 4}.

  6. Phosphomolybdate-doped-poly(3,4-ethylenedioxythiophene) coated gold nanoparticles: Synthesis, characterization and electrocatalytic reduction of bromate

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Stable and water soluble phosphomolybdate-doped-PEDOT coated gold nanoparticles were synthesized. •Electrodes modified with these nanoparticles show well defined voltammetric response and excellent stability in acidic media. •These nanocomposite catalysts exhibit an excellent catalytic activity towards electroreduction of bromate. -- Abstract: Phosphomolybdate, H3PMo12O40, (PMo12)-doped-poly(3,4-ethylenedioxythiophene) (PEDOT) coated gold nanoparticles have been synthesized in aqueous solution by reduction of AuCl4− using hydroxymethyl EDOT as a reducing agent in the presence of polystyrene sulfonate and PMo12. The resulting PMo12-doped-PEDOT stabilized Au nanoparticles are water soluble and have been characterized by UV–visible spectroscopy, scanning electron microscopy and electrochemistry. Glassy carbon electrodes modified with these Au nanoparticles show excellent stability and catalytic activity towards the reduction of bromate in an aqueous electrolyte solution containing 10 mM H2SO4 and 0.1 M Na2SO4

  7. Catálise eletroquímica da redução do bromato em superfícies modificadas por filmes de molibdênio Catalysis of the bromate reduction at a molybdenum oxide modified electrode

    OpenAIRE

    Mauro Bertotti; Derek Pletcher

    1998-01-01

    In this paper some studies concerning the electroreduction of Mo(VI) in sulphuric acid solutions are described. We have shown that at suitable experimental conditions very stable molybdenum oxide films can be electrochemically deposited at glassy carbon electrodes, the reduction of bromate occurring at less negative potentials on the modified surface. Coulometric experiments have shown that bromide is not the only product of the catalytic bromate reduction by the molybdenum film and species l...

  8. Anomalous genotoxic responses induced in mouse lymphoma L5178Y cells by potassium bromate

    International Nuclear Information System (INIS)

    Potassium bromate (KBrO3) is a well-established rodent kidney carcinogen and its oxidising activity is considered to be a significant factor in its mechanism of action. Although it has also been shown to be clearly genotoxic in a range of in vivo and in vitro test systems, surprisingly, it is not readily detected in several cell lines using the standard alkaline Comet assay. However, previous results from this laboratory demonstrated huge increases in tail intensity by modifying the method to include incubation with either human 8-oxodeoxyguanosine DNA glycosylase-1 (hOGG1) or bacterial formamidopyrimidine DNA glycosylase (FPG) indicating that, as expected, significant amounts of 8-oxodeoxyguanosine (8-OHdG) were induced. The purpose of this work, therefore, was to investigate why KBrO3, in contrast to other oxidising agents, gives a relatively poor response in the standard Comet assay. Results confirmed that it is a potent genotoxin in mouse lymphoma L5178Y cells inducing micronuclei and mutation at the tk and hprt loci at relatively non-cytotoxic concentrations. Subsequent time-course studies demonstrated that substantial amounts of 8-OHdG appear to remain in cells 24 h after treatment with KBrO3 but result in no increase in frank stand breaks (FSB) even though phosphorylated histone H2AX (γ-H2AX) antibody labelling confirmed the presence of double-strand breaks. Using bromodeoxyuracil (BrdU) incorporation together with measured increases in cell numbers, L5178Y cells also appeared to go through the cell cycle with unrepaired hOGG1-recognisable damage. Since unrepaired 8-OHdG can give rise to point mutations through G:C → T:A transversions, it was also surprising that mutation could not be detected at the Na+/K+ATPase locus as determined by ouabain resistance. Some increases in strand breakage could be seen in the Comet assay by increasing the unwinding time, but only at highly toxic concentrations and to a much smaller extent than would be expected from the

  9. Electrochemical Reduction of Bromate by a Pd Modified Carbon Fiber Electrode: Kinetics and Mechanism

    International Nuclear Information System (INIS)

    Highlights: • The BrO3− electroreduction proceeds with direct mechanism from 0 to -1.0 V. • The BrO3− electroreduction proceeds via atomic H* at more negative than -1.0 V. • Direct and indirect reduction result in strong and weak pH dependence respectively. • Pd facilitates oxygen atoms removal by hydrogenation without palladium-bonding. - Abstract: The electroreduction of bromate (BrO3−) was investigated at a Pd modified carbon fiber (Pd/C) electrode prepared from PdCl2 via electrodeposition method. Pd particles distributed on the carbon fiber substrate uniformly. Under various cathode potentials, electroreduction removal of BrO3− at pure carbon fiber electrode and the Pd/C electrode were firstly compared. It was observed that nearly no BrO3− removal was observed within the bias potential of -2.0 V at the carbon fiber electrode. At the Pd/C electrode, the removal efficiency of BrO3− was sharply increased from 24.0% to 58.4% at the cathode potential of -1.0 to -1.5 V, which was further increased to be 87.2% at -2.0 V. The electrochemical reduction of BrO3− was strongly pH-dependent at -0.5 V and the reduction rate could be enhanced at low pH. While at the potential of -2.0 V, a slight pH effect was observed. BrO3− electroreduction follows pseudo first-order kinetics; the rate constant k was firstly increased from 0.016 to 0.031 min−1 with the increase of the Pd loading amount from 0.31 to 0.73 mg/cm2, and then was decreased to 0.018 min−1 at a higher Pd loading amount of 1.05 mg/cm2. The Pd(0) nanoparticles played a significant role in forming atomic H* to realize indirect BrO3− reduction. The electrochemical reduction of BrO3− produces accumulated intermediates of HOBr and OBr−, which were subsequently reduced to Br− with the time evolution

  10. Development of a miniature dielectric barrier discharge–optical emission spectrometric system for bromide and bromate screening in environmental water samples

    International Nuclear Information System (INIS)

    Graphical abstract: -- Highlights: •Dielectric barrier discharge (DBD) is for the first time used as a radiation source for the excitation of bromine and its emission. •A DBD–optical emission spectrometric (OES) system was developed for the detection of bromide and bromate. •The DBD–OES system has been demonstrated by screening trace bromide and bromate in a series of environmental water samples. -- Abstract: Dielectric barrier discharge (DBD) at atmospheric pressure provides an efficient radiation source for the excitation of bromine and it is used for the first time for optical emission spectrometric (OES) detection of bromide and bromate. A portable DBD–OES system is developed for screening potential pollution from bromide and bromate in environmental waters. Bromide is on-line oxidized to bromine for in-situ generation of volatile bromine. Meanwhile, a helium stream carries bromine into the DBD micro-plasma for its excitation at a discharging voltage of 3.7 kV and optical emission spectrometric detection with a QE65000 charge-coupled device (CCD) spectrometer in the near-infrared spectral region. Similarly, the quantification of bromate is performed by its pre-reduction into bromide and then oxidized to bromine. The spectral characteristics and configuration of the DBD micro-plasma excitation source in addition to the oxidation vapor generation of bromine have been thoroughly investigated. With a sampling volume of 1 mL, a linear range of 0.05–10.0 mg L−1 is obtained with a detection limit of 0.014 mg L−1 by measuring the emission at 827 nm. A precision of 2.3% is achieved at 3 mg L−1 bromide. The system is validated by bromine detection in certified reference material of laver (GBW10023) at mg L−1 level, giving rise to satisfactory agreement. In addition, it is further demonstrated by screening trace bromide and bromate as well as spiking recoveries in a series of environmental water samples

  11. A New Reaction for Kinetic Spetrophotometric Determination of Trace Ruthenium--Catalytic Oxidation of Methyl Green by Bromate

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhi-rong; XU Qiong; XIONG Yan; WEI Jia-wen

    2006-01-01

    A sensitive catalytic spectrophotometric method for the determination of ruthenium (Ⅲ) has been developed, based on its catalytic effect on the oxidation reaction of methyl green with potassium bromate in acid solution medium at 100 ℃. The above reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 625 nm for the catalytic reaction of methyl green. The calibration curve for the recommended reaction-rate method was linear in the concentration range over 0.00-0.80 μg/L and the detection limit of the method for Ru (Ⅲ) is 0.006μg/L. Almost no foreign ions interfered in the determination at less than 25-fold concentration of Ru (Ⅲ). The method is highly sensitive, more selective and very stable, and has been successfully applied for the determination of trace ruthenium in some ores and metallurgy products.

  12. Spectrophotometric reaction rate method for the determination of osmium by its catalytic effect on the oxidation of gallocyanine by bromate.

    Science.gov (United States)

    Ensafi, A A; Shamss-E-Sollari, E

    1994-10-01

    A simple kinetic spectrophotometric method was developed for the determination of osmium. The method is based on the catalytic effect of osmium as osmium tetroxide on the oxidation of gallocyanine by bromate at pH 7. The reaction is monitored spectrophotometrically by measuring the decreasing absorbance of gallocyanine at 620 nm by the fixed-time method. A detection limit of 0.01 ng/ml and linear calibration curve from 0.1 to 100 and from 100 to 1200 ng/ml Os(VIII) is reported. The relative standard deviation for 0.0100 microg/ml Os(VIII) is 0.8% (N = 10). The method is free from most interferences. Osmium in synthetic samples is determined by this method, with satisfactory results. PMID:18966116

  13. The indirect effect of radiation reduces the repair fidelity of NHEJ as verified in repair deficient CHO cell lines exposed to different radiation qualities and potassium bromate

    Energy Technology Data Exchange (ETDEWEB)

    Bajinskis, Ainars, E-mail: ainars.bajinskis@gmt.su.se [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden); Olsson, Gunilla; Harms-Ringdahl, Mats [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden)

    2012-03-01

    The complexity of DNA lesions induced by ionizing radiation is mainly dependent on radiation quality, where the indirect action of radiation may contribute to different extent depending on the type of radiation under study. The effect of indirect action of radiation can be investigated by using agents that induce oxidative DNA damage or by applying free radical scavengers. The aim of this study was to investigate the role of the indirect effect of radiation for the repair fidelity of non-homologous end-joining (NHEJ), homologous recombination repair (HRR) and base excision repair (BER) when DNA damage of different complexity was induced by gamma radiation, alpha particles or from base damages (8-oxo-dG) induced by potassium bromate (KBrO{sub 3}). CHO cells lines deficient in XRCC3 (HRR) irs1SF, XRCC7 (NHEJ) V3-3 and XRCC1 (BER) EM9 were irradiated in the absence or presence of the free radical scavenger dimethyl sulfoxide (DMSO). The endpoints investigated included rate of cell proliferation by the DRAG assay, clonogenic cell survival and the level of primary DNA damage by the comet assay. The results revealed that the indirect effect of low-LET radiation significantly reduced the repair fidelity of both NHEJ and HRR pathways. For high-LET radiation the indirect effect of radiation also significantly reduced the repair fidelity for the repair deficient cell lines. The results suggest further that the repair fidelity of the error prone NHEJ repair pathway is more impaired by the indirect effect of high-LET radiation relative to the other repair pathways studied. The response to bromate observed for the two DSB repair deficient cell lines strongly support earlier studies that bromate induces complex DNA damages. The significantly reduced repair fidelity of irs1SF and V3-3 suggests that NHEJ as well as HRR are needed for the repair, and that complex DSBs are formed after bromate exposure.

  14. Cisapride a green analytical reagent for rapid and sensitive determination of bromate in drinking water, bread and flour additives by oxidative coupling spectrophotometric methods

    Science.gov (United States)

    Al Okab, Riyad Ahmed

    2013-02-01

    Green analytical methods using Cisapride (CPE) as green analytical reagent was investigated in this work. Rapid, simple, and sensitive spectrophotometric methods for the determination of bromate in water sample, bread and flour additives were developed. The proposed methods based on the oxidative coupling between phenoxazine and Cisapride in the presence of bromate to form red colored product with max at 520 nm. Phenoxazine and Cisapride and its reaction products were found to be environmentally friendly under the optimum experimental condition. The method obeys beers law in concentration range 0.11-4.00 g ml-1 and molar absorptivity 1.41 × 104 L mol-1 cm-1. All variables have been optimized and the presented reaction sequences were applied to the analysis of bromate in water, bread and flour additive samples. The performance of these method was evaluated in terms of Student's t-test and variance ratio F-test to find out the significance of proposed methods over the reference method. The combination of pharmaceutical drugs reagents with low concentration create some unique green chemical analyses.

  15. Mechanism of oxovanadium (IV)-catalysed and uncatalysed bromate oxidation of lactic acid in acid medium: evaluation of composite and individual kinetic and thermodynamic parameters

    International Nuclear Information System (INIS)

    Uncatalysed acid bromate oxidation of lactic acid (LA) exhibits fractional order (1.6) in [acid] and first order each in [Br(V)] and [LA]. Kinetic isotope effect (kH/kD=1) is absent, however an inverse solvent isotope effect (kH2O/kD2O=1.78 at 313 K) is observed. The mechanism proposed consists of a rate determining formation of bromate ester due to the nucleophilic attack by the alcoholic/hydroxyl group at the bromine atom of HOBrO2/H2O2Br+O, followed by a fast disproportionation of the ester through C-C bond cleavage to form products. Oxovanadium(IV)-catalysed LA-Br(V) reaction exhibits second order in [acid], fractional order in [lactic acid] and first order each in [VOSO4] and [oxidant]. The envisaged mechanism assumes a ternary complex formation involving a binary complex of LA and V(IV) and protonated bromate, which subsequently decomposes to the intermediate/products. The rate constants involved for each step of the reactions are evaluated along with their thermodynamic parameters. (author)

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

    KAUST Repository

    Liu, Chao

    2012-10-16

    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.

  17. Kinetics and mechanism of oxidation of dimethyl sulphoxide by sodium bromate-sodium bisulphite reagent in aqueous medium

    Indian Academy of Sciences (India)

    J Viroopakshappa; V Jagannadham

    2002-04-01

    Rates of oxidation of dimethyl sulphoxide (DMSO) by HOBr produced in situ from sodium bromate-sodium bisulphite reagent have been studied iodometrically in aqueous medium. The order in [DMSO] is one when [DMSO] < 0.01 mol dm-3, fractional when [DMSO] is between 0.01 and 0.5 mol dm-3 and zero when (DMSO) < 0.5 mol dm-3. Different rate laws are operative under these three conditions though HOBr is the effective oxidizing species in all the cases. A mechanism involving an intermediate four-membered cyclic transition state between DMSO and HOBr (formation constant ), which decomposes in a slow step with a rate constant () has been proposed. Thermodynamic parameters for the adduct formation step and activation parameters for the first-order decomposition of the adduct step have been evaluated in the temperature range 308-323 K. Activation parameters have also been determined while the orders in [DMSO] are unity and zero. The reaction product has been identified as dimethyl sulphone (DMSO2).

  18. Vanillin mitigates potassium bromate-induced molecular, biochemical and histopathological changes in the kidney of adult mice.

    Science.gov (United States)

    Ben Saad, Hajer; Driss, Dorra; Ellouz Chaabouni, Samia; Boudawara, Tahia; Zeghal, Khaled Mounir; Hakim, Ahmed; Ben Amara, Ibtissem

    2016-05-25

    The present study aimed to explore the ability of vanillin to ameliorate the adverse effects induced by potassium bromate (KBrO3) in the renal tissue. Our results showed a significant increase in hydrogen peroxide, superoxide anion, malondialdehyde, advanced oxidation protein product and protein carbonyl levels in the kidney of KBrO3 treated mice, compared with the control group. Nephrotoxicity was evidenced by a decrease in plasma uric acid and kidney glutathione levels, Na(+)-K(+)-ATPase, lactate dehydrogenase and catalase activities. Additionally, creatinine and urea levels significantly increased in the plasma and declined in the urine. Also, Kidney glutathione peroxidase, superoxide dismutase, metallothionein (MT1 and MT2) mRNA expression remarkably increased. These modifications in biochemical and molecular values were substantiated by histopathological data. Co-treatment with vanillin restored these parameters to near control values. Interestingly, vanillin proved to possess, in vitro, a stronger scavenging radical activity than vitamin C and Trolox. Thus, vanillin inhibited KBrO3-induced damage via its antioxidant and antiradical activities as well as its capacity to protect genes expression and histopathological changes. PMID:27074584

  19. pH-oscillations in the bromate-sulfite reaction in semibatch and in gel-fed batch reactors

    Science.gov (United States)

    Poros, Eszter; Kurin-Csörgei, Krisztina; Szalai, István; Rábai, Gyula; Orbán, Miklós

    2015-06-01

    The simplest bromate oxidation based pH-oscillator, the two component BrO3--SO32- flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH˜3), long lasting (11-24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3- with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3--SO32- pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications.

  20. The influence of the combined effects of acute gamma-radiation, sodium bromate and sodium nitrate on lettuce (Lactuca sativa) seedling root growth

    Energy Technology Data Exchange (ETDEWEB)

    Pryakhin, E.; Osipov, D. [Urals Research Center for Radiation Medicine - URCRM (Russian Federation)

    2014-07-01

    Among special industrial reservoirs used for the storage of liquid radioactive waste of Mayak PA, Russia, one of the most radioactively contaminated is the R-17 reservoir, so-called 'Staroye Boloto' (the total β-activity of water ranged in the observation period from 0.4 MBq/l to 4.5 MBq/l, the total a-activity ranged from 43 to 420 Bq/l). Also this reservoir is characterized by high level of chemical contamination, in particular, the concentration of nitrates in water is 2.5-4,4 g/l, sodium bromate - up to 35 mg/l. One of the interesting questions is interaction of radiation and chemical contamination in their effect on living organisms in this reservoir. In laboratory experiments seeds of Lactuca sativa were used; the effect of the studied factor on the length of the sprout's root was estimated. To assess the effect of chemical toxicants the solutions of each salt in 7 different concentrations were used, distilled water was used as a control. For evaluation of acute effects of external gamma irradiation the seeds after exposure for 24 hours in distilled water, were irradiated at 7 different doses using gamma-unit on the basis of Cs-137 with the dose rate of 0.62 Gy/min. To assess the combined effects of acute external gamma irradiation, of nitrates and bromates, seeds after 24 hour exposure at each test concentration of the salts solutions were irradiated using gamma-unit. To calculate the effective concentrations or doses was used drc package for R software. To calculate the dose rate to aquatic organisms in the R-17 was used ERICA Assessment Tool 2012. It was found out that the EC50 of sodium nitrate for lettuce was 2.69 g/l, which is comparable to the concentration of nitrates in the 'Staroye Boloto'. This indicates that nitrate can have significant toxic effect on aquatic higher plants of the reservoir. The EC50 of sodium bromate was 14.6 mg/l. This is less than the maximum concentration of the substance in the R-17, which suggests

  1. The influence of the combined effects of acute gamma-radiation, sodium bromate and sodium nitrate on lettuce (Lactuca sativa) seedling root growth

    International Nuclear Information System (INIS)

    Among special industrial reservoirs used for the storage of liquid radioactive waste of Mayak PA, Russia, one of the most radioactively contaminated is the R-17 reservoir, so-called 'Staroye Boloto' (the total β-activity of water ranged in the observation period from 0.4 MBq/l to 4.5 MBq/l, the total a-activity ranged from 43 to 420 Bq/l). Also this reservoir is characterized by high level of chemical contamination, in particular, the concentration of nitrates in water is 2.5-4,4 g/l, sodium bromate - up to 35 mg/l. One of the interesting questions is interaction of radiation and chemical contamination in their effect on living organisms in this reservoir. In laboratory experiments seeds of Lactuca sativa were used; the effect of the studied factor on the length of the sprout's root was estimated. To assess the effect of chemical toxicants the solutions of each salt in 7 different concentrations were used, distilled water was used as a control. For evaluation of acute effects of external gamma irradiation the seeds after exposure for 24 hours in distilled water, were irradiated at 7 different doses using gamma-unit on the basis of Cs-137 with the dose rate of 0.62 Gy/min. To assess the combined effects of acute external gamma irradiation, of nitrates and bromates, seeds after 24 hour exposure at each test concentration of the salts solutions were irradiated using gamma-unit. To calculate the effective concentrations or doses was used drc package for R software. To calculate the dose rate to aquatic organisms in the R-17 was used ERICA Assessment Tool 2012. It was found out that the EC50 of sodium nitrate for lettuce was 2.69 g/l, which is comparable to the concentration of nitrates in the 'Staroye Boloto'. This indicates that nitrate can have significant toxic effect on aquatic higher plants of the reservoir. The EC50 of sodium bromate was 14.6 mg/l. This is less than the maximum concentration of the substance in the R-17, which suggests that sodium bromate has a

  2. Reuse of sewage sludge as a catalyst in ozonation - Efficiency for the removal of oxalic acid and the control of bromate formation

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Gang [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Pan, Zhi-Hui [School Of Civil Engineering, Guangzhou University, Guangzhou 510006 (China); Ma, Jun, E-mail: majun@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Liu, Zheng-Qian, E-mail: liuzhengqian@gmail.com [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhao, Lei [School of Civil Engineering, Harbin Institute of Technology, Harbin 150090 (China); Li, Jun-Jing [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Sewage sludge was converted into catalyst (SBC) and characterized. Black-Right-Pointing-Pointer SBC can enhance oxalic acid degradation in ozonation. Black-Right-Pointing-Pointer Surface reaction mechanism is responsible for enhancement of ozonation by SBC. Black-Right-Pointing-Pointer SBC can control the formation of bromate in ozonation. Black-Right-Pointing-Pointer Several combined reasons for the control of bromate formation are proposed. - Abstract: Sewage derived sludge is produced with an annual amount increase of 2% all over the world and it is an urgent issue to be addressed by human being. In the present study, sludge was converted into sludge-based catalyst (SBC) with ZnCl{sub 2} as activation agent and characterized by several methods (e.g., scanning electron microscope, X-ray photoelectron spectroscope and Fourier transform infrared spectroscope). Then it was used as a catalyst to enhance the removal of refractory organic matter, oxalic acid, and to control the formation of bromate (BrO{sub 3}{sup -}) in bench semi-continuous ozonation experiments. The effects of various operating parameters on the control of BrO{sub 3}{sup -} formation were investigated. Furthermore, the mechanism for the enhancement of organic matter removal and the control of BrO{sub 3}{sup -} formation was discussed as well. Results indicate that the combination of SBC with ozone shows a strong synergistic effect, resulting in a notable improvement on oxalic acid removal. A crucial surface reaction mechanism for the enhancement of organic matter removal is proposed on the basis of negative effect of higher pH and no inhibition effect of tert-butanol. The control for BrO{sub 3}{sup -} formation was demonstrated and the reason for its control in the process of O{sub 3}/SBC is the combined effect of SBC reductive properties, ozone exposure decrease and hydrogen peroxide concentration increase.

  3. Chemoprotective Effect of Taurine on Potassium Bromate-Induced DNA Damage, DNA-Protein Cross-Linking and Oxidative Stress in Rat Intestine

    OpenAIRE

    Ahmad, Mir Kaisar; Khan, Aijaz Ahmed; Ali, Shaikh Nisar; Mahmood, Riaz

    2015-01-01

    Potassium bromate (KBrO3) is widely used as a food additive and is a major water disinfection by-product. It induces multiple organ toxicity in humans and experimental animals and is a probable human carcinogen. The present study reports the protective effect of dietary antioxidant taurine on KBrO3-induced damage to the rat intestine. Animals were randomly divided into four groups: control, KBrO3 alone, taurine alone and taurine+ KBrO3. Administration of KBrO3 alone led to decrease in the act...

  4. Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes

    Directory of Open Access Journals (Sweden)

    Kanakapura Basavaiah

    2008-06-01

    Full Text Available Four sensitive and rapid methods for the determination of stavudine (STV in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A, 610 nm (method B or 550 nm (method C. In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3 stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 µg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results.Este trabalho descreve quatro métodos rápidos e sensíveispara a determinação de estavudina (STV na matéria-prima ou em produtos formulados. Soluções aquosas de STV podem ser tituladas tratando-as com excesso de bromato-brometo em meio ácido clorídrico, seguido da determinação iodimétrica de bromo em excesso. Métodos espectrofotométricos tambémenvolvem a adição de excesso de bromato-brometo à amostra, seguida da determinação de bromo residual por adição de uma quantidade fixa de alaranjado de metila, índigo-carmim ou azul de timol, e de medidas de absorbância nos comprimentos de onda apropriados: 520, 610 ou 550 nm. Em todos os métodos, a quantidade de bromato consumida corresponde à quantidade de STV e

  5. Combination of UV absorbance and electron donating capacity to assess degradation of micropollutants and formation of bromate during ozonation of wastewater effluents.

    Science.gov (United States)

    Chon, Kangmin; Salhi, Elisabeth; von Gunten, Urs

    2015-09-15

    In this study, the changes in UV absorbance at 254 nm (UVA254) and electron donating capacity (EDC) were investigated as surrogate indicators for assessing removal of micropollutants and bromate formation during ozonation of wastewater effluents. To measure the EDC, a novel method based on size exclusion chromatography followed by a post-column reaction was developed and calibrated against an existing electrochemical method. Low specific ozone doses led to a more efficient abatement of EDC than of UVA254. This was attributed to the abatement of phenolic moieties in the dissolved organic matter (DOM), which lose their EDC upon oxidation, but are partially transformed into quinones, which still absorb in the measured UV range. For higher specific ozone doses, the relative EDC abatement was lower than the relative UVA abatement, which can be explained by the oxidation of UV absorbing moieties (e.g. non-activated aromatic compounds), which contribute less to EDC. The abatement of the selected micropollutants (i.e., 17α-ethinylestradiol (EE2), carbamazepine (CBZ), atenolol (ATE), bezafibrate (BZF), ibuprofen (IBU), and p-chlorobenzoic acid (pCBA)) varied significantly depending on their reactivity with ozone in the examined specific ozone dose range of 0-1.45 mgO3/mgDOC. The decrease of EE2 and CBZ with high ozone reactivity was linearly proportional to the reduction of the relative residuals of UVA254 and EDC. The abatement of ATE, BZF, IBU, and pCBA with intermediate to low ozone reactivities was not significant in a first phase (UVA254/UVA254,0 = 1.00-0.70; EDC/EDC0 = 1.00-0.56) while their abatement was more efficient than the degradation of the relative residual UVA254 and much more noticeable than the degradation of the relative residual EDC in a second phase (UVA254/UVA254,0 = 0.70-0.25; EDC/EDC0 = 0.56-0.25) because the partially destroyed UV absorbing and electron donating DOM moieties become recalcitrant to ozone attack. Bromate formation was

  6. Oscillatory reactions in the acetone-glucose-sodium bromate-sulfuric acid system with a tetraazamacrocyclic copper (II complex as a catalyst

    Directory of Open Access Journals (Sweden)

    Hu Lin

    2016-01-01

    Full Text Available The behavior of glycolysis concerning the biochemical reaction was thought to be similar to the oscillatory reaction with glucose being the substrate. The objective of this research is to find a new oscillatory system and study its relevant properties, so new Cu (II-catalyzed oscillating reaction involved glucose and acetone as the double substrates was investigated systematically. As a function of reaction temperature and concentration of glucose, bromate, and acetone, the features in this novel oscillation system was studied. The results showed that the activation energy reached up to 90.839 KJ/mol and the oxidized product of the double substrates provided the impetus in the course of the new oscillating reaction. A tentative mechanism was considered on the basis of FNK.

  7. The Protective Effect of Ethanolic Extract of Unripe Pulp of Carica papaya (Pawpaw Against Potassium Bromate Induced Tissue Damage in Wistar Rats

    Directory of Open Access Journals (Sweden)

    S.J. Josiah

    2011-11-01

    Full Text Available The protective role of ethanolic extract of unripe pulp of Carica papaya (fruit, against potassiumbromate induced tissue damage in wistar rats was investigated. The animals were grouped into four groups (A, B, C, D of five rats. Group A was administered 1 mL of 0.25 M sucrose solution. 60 mg/kg of Potassium bromate KBrO3 was administered orally to rats in groups B, C and D. Groups C and D were pretreated with 250 and 500 mg/kg of the extracts for fourteen (14 days, respectively. The organ to body-weight ratio, total amino acid, total protein and malondialdeyde (MDA concentration in the brain, spleen, kidney, liver, and heart were colorimetrically measured as an assessment of the level of tissue damage. All the parameters studied increases significantly in all the tissues of rats group B. There was significant decrease in the organ-to-body weight ratio and total protein level in all the tissues investigated (p<0.05, when compared with Group B at both doses of the extract. The total protein level of the stomach had a drastic reduction at 500 mg/kg. Also, the Amino acid level of investigated tissues decreased significantly, while malondialdeyde levels decreased significantly in a dose dependent manner. These findings suggest that ethanolic extract of unripe pulp of Carica papaya may be protective against KBrO3 induced tissue damage in Wistar rats.

  8. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  9. Photo-reduction of bromate in drinking water by metallic Ag and reduced graphene oxide (RGO) jointly modified BiVO4 under visible light irradiation.

    Science.gov (United States)

    Chen, Fei; Yang, Qi; Zhong, Yu; An, Hongxue; Zhao, Jianwei; Xie, Ting; Xu, Qiuxiang; Li, Xiaoming; Wang, Dongbo; Zeng, Guangming

    2016-09-15

    Bromate (BrO3(-)), an oxyhalide disinfection by-product (DBP) in drinking water, has been demonstrated to be carcinogenic and genotoxic. In the current work, metallic Ag and reduced graphene oxide (RGO) co-modified BiVO4 was successfully synthesized by a stepwise chemical method coupling with a photo-deposition process and applied in the photo-reduction of BrO3(-) under visible light irradiation. In this composite, metallic Ag acted as an electron donor or mediator and RGO enhanced the BrO3(-) adsorption onto the surface of catalysts as well as an electron acceptor to restrict the recombination of photo-generated electron-hole pairs. The Ag@BiVO4@RGO composite exhibited greater photo-reduction BrO3(-) performance than pure BiVO4, Ag@BiVO4 and RGO@BiVO4 under identical experimental conditions: initial BrO3(-) concentration 150 μg/L, catalyst dosage 0.5 g/L, pH 7.0 and visible light (λ > 420 nm). The photoluminescence spectra (PL), electron-spin resonance (ESR), photocurrent density (PC) and electrochemical impedance spectroscopy (EIS) measurements indicated that the modified BiVO4 enhanced the photo-generated electrons and separated the electron-hole pairs. The photocatalytic reduction efficiency for BrO3(-) removal decreased with the addition of electron quencher K2S2O8, suggesting that electrons were the primary factor in this photo-reduction process. The declining photo-reduction efficiency of BrO3(-) in tap water should attribute to the consumption of photo-generated electrons by coexisting anions and the adsorption of dissolved organic matter (DOM) on graphene surface. The overall results indicate a promising application potential for photo-reduction in the DBPs removal from drinking water. PMID:27311108

  10. Formation of bromate and halogenated disinfection byproducts during chlorination of bromide-containing waters in the presence of dissolved organic matter and CuO

    KAUST Repository

    Liu, Chao

    2015-12-02

    Previous studies showed that significant bromate (BrO3-) can be formed via the CuO-catalyzed disproportionation of hypobromous acid (HOBr) pathway. In this study, the influence of CuO on the formation of BrO3- and halogenated disinfection byproducts (DBPs) (e.g., trihalomethanes, THMs and haloacetic acids, HAAs) during chlorination of six dissolved organic matter (DOM) isolates was investigated. Only in the presence of slow reacting DOM (from treated Colorado River water, i.e., CRW-BF-HPO), significant BrO3- formation is observed, which competes with bromination of DOM (i.e., THM and HAA formation). Reactions between HOBr and 12 model compounds in the presence of CuO indicates that CuO-catalyzed HOBr disproportionation is completely inhibited by fast reacting phenols, while it predominates in the presence of practically unreactive compounds (acetone, butanol, propionic, and butyric acids). In the presence of slow reacting di- and tri-carboxylic acids (oxalic, malonic, succinic, and citric acids), BrO3- formation varies, depending on its competition with bromoform and dibromoacetic acid formation (i.e., bromination pathway). The latter pathway can be enhanced by CuO due to the activation of HOBr. Therefore, increasing CuO dose (0-0.2 g L-1) in a reaction system containing chlorine, bromide, and CRW-BF-HPO enhances the formation of BrO3-, total THMs and HAAs. Factors including pH and initial reactant concentrations influence the DBP formation. These novel findings have implications for elevated DBP formation during transportation of chlorinated waters in copper-containing distribution systems.

  11. Enhanced formation of bromate and brominated disinfection byproducts during chlorination of bromide-containing waters under catalysis of copper corrosion products.

    Science.gov (United States)

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

    2016-07-01

    Copper corrosion products (CCPs) in water distribution pipes may catalyze the reactions among disinfectant, natural organic matter (NOM), and bromide (Br(-)). This study investigated the simultaneous formation of bromate (BrO3(-)) and brominated disinfection byproducts (Br-DBPs) during chlorination of Br(-)-containing waters in the presence of three CCPs (i.e., CuO, Cu2O, and Cu(2+)). In a synthetic water, both oxidant decay and BrO3(-) formation were enhanced by CCPs, whereas the presence of humic acid (HA) significantly inhibited BrO3(-) formation due to its competition for HOBr to form Br-DBPs. In the HOClBr(-)CuO system, the BrO3(-) yield increased obviously with increasing CuO dose and initial Br(-) concentration, while the catalytic formation of Br-DBPs was rather limited. A molar conversion (Br(-) to BrO3(-)) of 22.1% was observed under CuO catalysis, compared with little conversion in the absence of CuO. In the HOClBr(-)Cu2O/Cu(2+) systems, Cu2O or Cu(2+) mainly enhanced the formation of Br-DBPs, with enhancement ratios of 69.9% and 50.1%, respectively. The degree of enhancement on Br-DBPs formation became more apparent with increasing pH, while that on BrO3(-) formation reached maximal at pH 7.6. The catalytic formation of Br-DBPs and BrO3(-) by CCPs was also verified in three filtered real waters, although to a lesser extent because of the water matrix effect. In mechanism, the CCPs promoted the formation of BrO3(-) and Br-DBPs through catalyzing the HOBr disproportionation pathway and the reaction of HOBr toward HA, respectively. PMID:27110886

  12. Micronucleus test of varying amounts of potassium bromate (KBrO3) on the meristematic cells of Allium cepa var. aggregatum root tips

    International Nuclear Information System (INIS)

    Four hundred twenty onion bulbs of the multiplier variety Allium cepa var. aggregatum were used as test materials to assay the micronucleus induction capacity of potassium bromate doses of 0, 5, 10, 25, 50, 75, and 100 parts per million. Microscopic analyses were done using onion root tips prepared according to a modified technique of Medina (1994). These analyses were done on root tips taken from onions grown in KBrO3 for three days and for five days. The study was conducted following a completely randomized design and the data were statistically analyzed using a non-parametric equivalent of the analysis of variance. A significant amount of micronucleated cells (MCN) were found among treated onions compared with the almost non-occurrence in the control groups (0 ppm). The Kruskal-Wallis H-test and the Wilcoxon two-samples tests revealed significant differences among treatment means and that a significant increase in the number of MCN occurs as the dose of KBr03 increased in both day experiments. Results from the higher doses of 50, 75, and 100 ppm were found to be significantly the same for the day 3 experiments while those of the day 5 higher doses are characterized by lack of clear cellular and nuclear outline such that scoring is difficult. Differences in MCN averages for the day 3 and 5 experiments appear to be insignificant. However, day 3 results show averages that are more significantly different from each other. These prove that the MCN can be used as an efficient and time-saving parameter for the allium test of chemicals with chromosome breaking capacities. (Author)

  13. Possible participation of oxidative stress in causation of cell proliferation and in vivo mutagenicity in kidneys of gpt delta rats treated with potassium bromate

    International Nuclear Information System (INIS)

    Clarifying the participation of oxidative stress among possible contributing factors in potassium bromate (KBrO3)-induced carcinogenesis is of importance from the perspective of human health protection. In the present study, utilizing the antioxidative effects of α-tocopherol (α-TP) or sodium ascorbic acid (SAA) to attenuate oxidative stress, alterations in bromodeoxyuridine labeling indices (BrdU-LIs) and reporter gene mutations in kidneys of male and female gpt delta rats given KBrO3 were examined. Five male and female gpt delta rats in each group were given KBrO3 at a concentration of 500 ppm in the drinking water for 9 weeks, with 1% of α-TP or SAA administered in the diet from 1 week prior to the KBrO3 treatment until the end of the experiment. Increases in 8-hydroxydeoxyguanosine levels in kidney DNA of both sexes of rats given KBrO3 were significantly inhibited by SAA, but not α-TP. While BrdU-LIs in the proximal tubules of female rats were also significantly reduced by SAA, those in the males and gpt mutant frequencies in kidney DNA of both sexes were not affected by SAA or α-TP. Immunohistochemical and Western blot analyses for α2u-globulin strongly suggested that induction of cell proliferation observed in the males might primarily result from accumulation of this protein, independent of oxidative stress. The overall data indicated that while oxidative stress well correlates with induction of cell proliferation in females, its role in males and in generation of in vivo mutagenicity by KBrO3 in both sexes is limited

  14. Cerium incorporated MCM-48 (Ce-MCM-48) as a catalyst to inhibit bromate formation during ozonation of bromide-containing water: Efficacy and mechanism.

    Science.gov (United States)

    Li, Weiwei; Lu, Xiaowei; Xu, Ke; Qu, Jiuhui; Qiang, Zhimin

    2015-12-01

    The composite mesoporous sieve Ce-MCM-48 (cerium incorporated MCM-48) with different Si/Ce molar ratios were synthesized hydrothermally and characterized with X-ray diffraction, X-ray photoelectron spectroscopy, BET surface area, and pHpzc. Results indicate that Ce-MCM-48, especially with a Si/Ce molar ratio of 66 (i.e., Ce66-MCM-48), could significantly inhibit bromate (BrO3(-)) formation during ozonation of Br(-)-containing water, achieving 91% of inhibition efficiency at pH 7.6 and 25 °C. An acidic or alkaline pH decreased the inhibition efficiency of Ce66-MCM-48 to some extent, but reaction temperature ranging from 15 to 30 °C had no significant impact. By comparing the bromine mass balance, aqueous O3 decomposition, and newly formed H2O2 between O3 and O3/Ce66-MCM-48 processes, the inhibition mechanism was proposed: Ce66-MCM-48 promoted aqueous O3 decomposition to generate hydroxyl radicals (OH) that could merge into H2O2, so the oxidative transformation of Br(-) and HOBr/OBr(-) by O3 and OH was primarily suppressed. The catalytic ability of Ce66-MCM-48 was continuously regenerated through the circulating reactions between Ce(III) and Ce(IV) occurring on the catalyst surface. Besides its inhibition on BrO3(-) formation, Ce66-MCM-48 could also enhance the degradation of refractory organic micropollutants. Because of these distinct merits, Ce66-MCM-48 has potential applications to water treatment by ozone. PMID:26072989

  15. Graphene-modified Pd/C cathode and Pd/GAC particles for enhanced electrocatalytic removal of bromate in a continuous three-dimensional electrochemical reactor.

    Science.gov (United States)

    Mao, Ran; Zhao, Xu; Lan, Huachun; Liu, Huijuan; Qu, Jiuhui

    2015-06-15

    Bromate (BrO3(-)) is a carcinogenic and genotoxic contaminant commonly generated during ozonation of bromide-containing water. In this work, the reductive removal of BrO3(-) in a continuous three-dimensional electrochemical reactor with palladium-reduced graphene oxide modified carbon paper (Pd-rGO/C) cathode and Pd-rGO modified granular activated carbon (Pd-rGO/GAC) particles was investigated. The results indicated that the rGO sheets significantly promoted the electrochemical reduction of BrO3(-). With the enhanced electron transfer by rGO sheets, the electroreduction of H2O to atomic H* on the polarized Pd particles could be significantly accelerated, leading to a faster reaction rate of BrO3(-) with atomic H*. The synergistic effect of the Pd-rGO/C cathode and Pd-rGO/GAC particles were also exhibited. The atomic H* involved in various electroreduction processes was detected by electron spin resonance spectroscopy and its role for BrO3(-) reduction was determined. The performance of the reactor was evaluated in terms of the removal of BrO3(-) and the yield of Br(-) as a function of the GO concentration, Pd loading amount, current density, hydraulic residence time (HRT), and initial BrO3(-) concentration. Under the current density of 0.9 mA/cm(2), BrO3(-) with the initial concentration of 20 μg/L was reduced to be less than 6.6 μg/L at the HRT of 20 min. The BrO3(-) reduction was inhibited in the presence of dissolved organic matter. Although the precipitates generated from Ca(2+) and Mg(2+) in the tap water would cover the Pd catalysts, a long-lasting electrocatalytic activity could be maintained for the 30 d treatment. SEM and XPS analysis demonstrated that the precipitates were predominantly deposited onto the Pd-rGO/C cathode rather than the Pd-rGO/GAC particles. PMID:25834955

  16. Electrosorption of Os(III)-complex at single-wall carbon nanotubes immobilized on a glassy carbon electrode: Application to nanomolar detection of bromate, periodate and iodate

    Energy Technology Data Exchange (ETDEWEB)

    Salimi, Abdollah [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)], E-mail: absalimi@uok.ac.ir; Kavosi, Begard [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Department of Chemistry, Arak University, P.O. Box, 38156-879 Arak (Iran, Islamic Republic of); Babaei, Ali [Department of Chemistry, Arak University, P.O. Box, 38156-879 Arak (Iran, Islamic Republic of); Hallaj, Rahman [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)

    2008-06-16

    A simple procedure was developed to prepare a glassy carbon electrode modified with single-wall carbon nanotubes (SWCNTs) and Os(III)-complex. The glassy carbon (GC) electrode modified with CNTs was immersed into Os(III)-complex solution (direct deposition) for a short period of time (60 s). 1,4,8,12-Tetraazacyclotetradecane osmium(III) chloride, (Os(III)LCl{sub 2}).ClO{sub 4}, irreversibly and strongly adsorbed on SWCNTs immobilized on the surface of GC electrode. Cyclic voltammograms of the Os(III)-complex-incorporated-SWCNTs indicate a pair of well defined and nearly reversible redox couple with surface confined characteristic at wide pH range (1-8). The surface coverage ({gamma}) and charge transfer rate constant (k{sub s}) of the immobilized Os-complex on SWCNTs were 3.07 x 10{sup -9} mol cm{sup -2}, 5.5 ({+-}0.2) s{sup -1}, 2.94 x 10{sup -9} mol cm{sup -2}, 7.3 ({+-}0.3) s{sup -1} at buffer solution with pH 2 and 7, respectively, indicate high loading ability of SWCNTs for Os(III) complex and great facilitation of the electron transfer between electroactive redox center and carbon nanotubes immobilized on the electrode surface. Modified electrodes showed higher electrocatalytic activity toward reduction of BrO{sub 3}{sup -}, IO{sub 3}{sup -} and IO{sub 4}{sup -} in acidic solutions. The catalytic rate constants for catalytic reduction bromate, periodate and iodate were 3.79 ({+-}0.2) x 10{sup 3}, 7.32 ({+-}0.2) x 10{sup 3} and 1.75 ({+-}0.2) x 10{sup 3} M{sup -1} s {sup -1}, respectively. The hydrodynamic amperometry of rotating modified electrode at constant potential (0.3 V) was used for nanomolar detection of selected analytes. Excellent electrochemical reversibility of the redox couple, good reproducibility, high stability, low detection limit, long life time, fast amperometric response time, wide linear concentration range, technical simplicity and possibility of rapid preparation are great advantage of this sensor.

  17. 感潮珠江原水臭氧氧化副产物BrO3-预测模型的建立%Modeling of bromate formation during ozonation process of surface water in the Pearl River Basin affected by seawater intrusion

    Institute of Scientific and Technical Information of China (English)

    胡冰; 吴纯德; 张之琳; 胡彩霞; 梁佳莉; 梁国建; 刘吕刚

    2013-01-01

    以珠江流域西江中山段的感潮原水为对象,模拟其臭氧预处理、常规处理和臭氧活性炭处理,考察原水预、主臭氧对应投加量时溴酸盐生成情况,构建了预、主臭氧溴酸盐生成经验预测模型.结果表明,在预臭氧过程中,高的DOC、O3及Br-浓度,会增加溴酸盐的生成量,升高pH,提高NH3-N及IC有利于抑制溴酸盐的形成;在主臭氧过程中,升高pH,提高O3及Br-浓度,会增加溴酸盐的生成量,而高的DOC、NH3-N及IC会降低溴酸盐的形成风险.所建模型预测实际水样,发现预、主臭氧预测模型预测误差分别为33.72%和13.22%.%In this study, by selecting the raw water of Xijiang Zhongshan section of the Pearl River Basin affected by seawater intrusion and simulating the processes of preozonation, general treatment, postozonation and GAC, the bromate formation of different ozone dosages and modeling of bromate formation during preozonation and later ozonation process was studied. The results show that during preozonation process, high concentrations of DOC, O3 and Br- in raw water, lead to more generation of bromate, while pH,NH3-N and IC can suppress bromate formation under cetain conditions. During postozonation process, bromate concentration increases increases of pH value, ozone and bromine concentration, but high concentrations of DOC, NH3-N and IC reduce the risk of the bromate formation. For predicting water samples, the forecast errors of the formation modelings during preozonation process and later qzonation process are 33. 72% and 13. 22%, respectively.

  18. Seguiment i interpretació de la degradació de contaminants bromats mitjançant tècniques cromatogràfiques, espectroscòpiques i quimiomètriques

    OpenAIRE

    Mas Garcia, Silvia

    2012-01-01

    [cat]Aquesta Tesi Doctoral presenta l’estudi de degradació de dues classes de retardants de flama bromats (els difenilèters polibromats (PBDEs) i els bromofenols) mitjançant tècniques espectroscòpiques, cromatogràfiques i quimiomètriques. S’ha estudiat dos tipus de degradació: la fotodegradaciói la biodegradació. A més dels estudis específics d’aquests processos, s’ha treballat en la revisió de metodologia existent i en el desenvolupament de nous procediments per a la interpretació d’informac...

  19. Validação do método de determinação simultânea dos íons brometo e bromato por cromatografia iônica em águas de consumo humano Validation of simultaneous determination of bromides and bromates by ion chromatography in drinking water

    OpenAIRE

    Maria Edite Pinto Gonçalves; Maria Filomena Camões; João Miguel Paiva; Maria João Benoliel; Rui Neves Carneiro

    2004-01-01

    European Directive (98/83/CE), compulsory after 2008, states that bromate in drinking water must be controlled at levels below 10 mg L-1. Supporting implementation of the Directive, the European Comission has established project SMT4-CT96 2134, in collaboration with various european institutions, aiming at the identification of the interferents to the current analytical method (Ionic Chromatography with Conductimetric Detection - IC/CD), their removal and the automation of pre-treatment and i...

  20. Validação do método de determinação simultânea dos íons brometo e bromato por cromatografia iônica em águas de consumo humano Validation of simultaneous determination of bromides and bromates by ion chromatography in drinking water

    Directory of Open Access Journals (Sweden)

    Maria Edite Pinto Gonçalves

    2004-06-01

    Full Text Available European Directive (98/83/CE, compulsory after 2008, states that bromate in drinking water must be controlled at levels below 10 mg L-1. Supporting implementation of the Directive, the European Comission has established project SMT4-CT96 2134, in collaboration with various european institutions, aiming at the identification of the interferents to the current analytical method (Ionic Chromatography with Conductimetric Detection - IC/CD, their removal and the automation of pre-treatment and injection steps, as well as the development of alternative methods. EPAL, responsible for the water supply to a great deal of Portuguese regions, has taken steps to meet these requirements. Although not part of such project, this work (the result of a project conducted under a protocol of collaboration between EPAL SA and FCUL - Faculty of Sciences, University of Lisbon, reports on studies of usefulness to laboratories planning to monitor bromate in ozone treated waters, in conditions different from those described in EPA 300.1. Simultaneous determination of bromide is justified by its role as bromate precursor.

  1. Method for the fast determination of bromate, nitrate and nitrite by ultra performance liquid chromatography-mass spectrometry and their monitoring in Saudi Arabian drinking water with chemometric data treatment.

    Science.gov (United States)

    Khan, Mohammad Rizwan; Wabaidur, Saikh Mohammad; Alothman, Zeid Abdullah; Busquets, Rosa; Naushad, Mu

    2016-05-15

    A rapid, sensitive and precise method for the determination of bromate (BrO3(-)), nitrate (NO3(-)) and nitrite (NO2(-)) in drinking water was developed with Ultra performance Liquid Chromatography-Mass Spectrometry (UPLC-ESI/MS). The elution of BrO3(-), NO3(-) and NO2(-) was attained in less than two minutes in a reverse phase column. Quality parameters of the method were established; run-to-run and day-to-day precisions were NO2(-)L(-1) and 0.03µgL(-1) for both NO3(-)and BrO3(-). The developed UPLC-ESI/MS method was used to quantify these anions in metropolitan water from Saudi Arabia (Jeddah, Dammam and Riyadh areas) and commercial bottled water (from well or unknown source) after mere filtration steps. The quantified levels of NO3(-) were not found to pose a risk. In contrast, BrO3(-) was found above the maximum contaminant level established by the US Environmental Protection Agency in 25% and 33% of the bottled and metropolitan waters, respectively. NO2(-) was found at higher concentrations than the aforementioned limits in 70% and 92% of the bottled and metropolitan water samples, respectively. Therefore, remediation measures or improvements in the disinfection treatments are required. The concentrations of BrO3(-), NO3(-) and NO2(-) were mapped with Principal Component analysis (PCA), which differentiated metropolitan water from bottled water through the concentrations of BrO3(-) and NO3(-) mainly. Furthermore, it was possible to discriminate between well water; blend of well water and desalinated water; and desalinated water. The point or source (region) was found to not be distinctive. PMID:26992549

  2. Immobilization of [Cu(bpy){sub 2}]Br{sub 2} complex onto a glassy carbon electrode modified with {alpha}-SiMo{sub 12}O{sub 40}{sup 4-} and single walled carbon nanotubes: Application to nanomolar detection of hydrogen peroxide and bromate

    Energy Technology Data Exchange (ETDEWEB)

    Salimi, Abdollah [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of)], E-mail: absalimi@uok.ac.ir; Korani, Aazam; Hallaj, Rahman; Khoshnavazi, Roshan [Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj (Iran, Islamic Republic of); Hadadzadeh, Hasan [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-03-02

    A simple procedure has been used for preparation of modified glassy carbon electrode with carbon nanotubes and copper complex. Copper complex [Cu(bpy){sub 2}]Br{sub 2} was immobilized onto glassy carbon (GC) electrode modified with silicomolybdate, {alpha}-SiMo{sub 12}O{sub 40}{sup 4-} and single walled carbon nanotubes (SWCNTs){sub .} Copper complex and silicomolybdate irreversibly and strongly adsorbed onto GC electrode modified with CNTs. Electrostatic interactions between polyoxometalates (POMs) anions and Cu-complex, cations mentioned as an effective method for fabrication of three-dimensional structures. The modified electrode shows three reversible redox couples for polyoxometalate and one redox couple for Cu-complex at wide range of pH values. The electrochemical behavior, stability and electron transfer kinetics of the adsorbed redox couples were investigated using cyclic voltammetry. Due to electrostatic interaction, copper complex immobilized onto GC/CNTs/{alpha}-SiMo{sub 12}O{sub 40}{sup 4-} electrode shows more stable voltammetric response compared to GC/CNTs/Cu-complex modified electrode. In comparison to GC/CNTs/Cu-complex the GC/CNTs/{alpha}-SiMo{sub 12}O{sub 40}{sup 4-} modified electrodes shows excellent electrocatalytic activity toward reduction H{sub 2}O{sub 2} and BrO{sub 3}{sup -} at more reduced overpotential. The catalytic rate constants for catalytic reduction hydrogen peroxide and bromate were 4.5({+-}0.2) x 10{sup 3} M{sup -1} s{sup -1} and 3.0({+-}0.10) x 10{sup 3} M{sup -1} s{sup -1}, respectively. The hydrodynamic amperommetry technique at 0.08 V was used for detection of nanomolar concentration of hydrogen peroxide and bromate. Detection limit, sensitivity and linear concentration range proposed sensor for bromate and hydrogen peroxide detection were 1.1 nM and 6.7 nA nM{sup -1}, 10 nM-20 {mu}M, 1 nM, 5.5 nA nM{sup -1} and 10 nM-18 {mu}M, respectively.

  3. Thermal dehydration and the effect of crystal transformation on 80Br retention in strontium bromate monohydrate

    International Nuclear Information System (INIS)

    Isothermal dehydration and isothermal annealing of neutron activated Sr(BrO3)2.H2O was studied in the temperature range 80-225 degC. Fractional dehydration at 80 degC observed to be 0.02 increasing to 0.3 at 100 degC for the same 30 min. heating period indicating the crystal transformation between 80-100 degC. 80Br initial retention, 11.3% raised to 28.0% for heating at 100 degC for 30 min. indicating some structural rearrangement. Activation energy involved for Sr(BrO3)2.H2O and Sr(BrO3)2 was 0.06 and 0.12eV where as it was 2.1 x 10-2) for isothermal dehydration. (author). 4 refs. 1 tab

  4. Evaluation of pre-treatments for inhibiting bromate formation during ozonation

    DEFF Research Database (Denmark)

    Antoniou, Maria; Andersen, Henrik Rasmus

    2011-01-01

    This study compared several pre-treatment methods for inhibiting BrO3- formation during ozonation of tap water, from the DTU campus, including H2O2 addition (perozone), pH-depression, NH4+ and Cl2/NH4+ addition. At the same time, the inhibition of atrazine and carbamazepine removal was evaluated...

  5. Kinetic study of thermal/radiation annealing and dehydration of nickel, bromate following 79Br(n,γ)80Br reaction

    International Nuclear Information System (INIS)

    The initial retentions of 80Br,sup(80m)Br and 82Br following neutron activation with 252Cf source of Ni(BrO3)2.6H2O at 25deg C are 17,19 and 31 +- 1% respectively. Heat and radiation treatments yield higher 80Br recovery in the hydrated salt than in the anhydrous salt. At 110deg C 80Br retention rises suddenly to close on 100% in the hydrated salt while in the anhydrous salt it increases from 22 to 42%. In both the cases thermal annealing carried over the temperature range 25-110deg C follows first order kinetics and shows 77deg C as the threshold annealing temperature. The rate of annealing increases with the rate of dehydration. The annealing data yield 2.7 and 0.49 eV as the activation energy values for the hydrated and dehydrated forms respectively while isothermal dehydration data yield the value as 0.31 eV. A probable mechanism is suggested. (author)

  6. Bromide en bromaat in drink- en oppervlaktewater

    OpenAIRE

    Versteegh JFM; Neele J; Cleven RFMJ; Smeenk JGMM; Westra R

    1993-01-01

    This report describes the results of research done in 1992 after the occurrence of bromate during the production of drinking water. A survey was carried out among five drinking water plants ; surface waters of the rivers Rhine and Meuse were included as well. Bromate is only occasionnally present in the raw water, during treatment and in finished drinking water (<10 mug/l). The results do not give conclusions on the behaviour of bromate during treatment processes. Experiments at pilot plan...

  7. 焙烧条件对Ru/AC催化剂去除溴酸盐的影响%Effect of Calcination Conditions on the Activity of Activated Carbon Supported with Ruthenium Catalyst for Bromate Reduction

    Institute of Scientific and Technical Information of China (English)

    朱佳; 董紫君; 陶益; 董文艺

    2014-01-01

    考察了以RuCl3·3H2O为前驱物,以AC(颗粒活性炭)为载体制备Ru/AC时,焙烧氛围、焙烧温度、焙烧时间对Ru/AC催化活性的影响,并利用XPS(X-ray photoelectron spectra,X射线光电子能谱分析)、BET(brunner-emmet-teller method,比表面积测定)和SEM(scanning electronic microscopy,扫描电镜)等手段对样品进行了表征.结果表明,不同焙烧氛围中制备的Ru/AC活性有较大差异:在N2焙烧氛围中,容易形成去除BrO3-的有效活性组分(RuO2);而在真空焙烧氛围中,几乎没有活性组分的产生;在H2-N2[φ(H2)为1.5%,φ(N2)为98.5%]氛围中焙烧,负载在AC上的活性组分有Ru0(单质钌)和RuO2.焙烧温度对Ru/AC去除BrO3的性能有着较为显著的影响,高温有利于AC的石墨化进程,载体性能得到优化;但焙烧温度过高(1 000℃)时,会产生金属颗粒团聚现象;最适宜的焙烧温度为900℃.Ru/AC的活性随着焙烧时间的延长呈先增后降的趋势;焙烧时间为3h时,载体的比表面积和孔容积得到提高且有效活性组分能够均匀地分散在AC载体上.综上,Ru/AC催化剂的最优焙烧条件:焙烧氛围为N2,焙烧温度为900℃,焙烧时间为3h.在该条件下制备的Ru/AC利于形成去除BrO3-的活性物质RuO2,并且其能够均匀地分布在AC载体上,使催化反应进行得更为彻底,可在2h内将BrO3-全部去除.

  8. X-ray, i.r., and Raman studies of the anhydrous chlorates and bromates of strontium, barium, and lead - crystal structure of Sr(ClO3)2 and Sr(BrO3)2

    International Nuclear Information System (INIS)

    Single crystals of the hitherto badly characterized anhydrous halates Sr(ClO3)2, Sr(BrO3)2, Ba(BrO3)2, Pb(ClO3)2, and Pb(BrO3)2 have been obtained by crystallization from an aqueous solution or by heating aqueous suspensions of the corresponding monohydrates to 95, 185, 130, and 105 0C, respectively, in a vacuum. The halates crystallize in the orthorhombic space group Fdd2-C/sub 2v//sup 19/ (Z = 8) with the exception of Sr(BrO3)2, which is distorted to the monoclinic space group Cc-C/sub s//sup 4/ (Z = 4). The crystal structure of Sr(ClO3)2 and Sr(BrO3)2 have been determined using single crystal X-ray diffraction data. In both compounds, distorted SrO8 dodecahedra (bisphenoids) are connected to a four-connected three-dimensional net. The ClO3- ions and one of the two crystallographically non-equivalent BrO3- ions are strongly distorted. The structures of these compounds and those of Ba(IO3)2 and of Ba(ClO3)2 x 1 H2O type compounds are related to a hypothetical AB2 structure with diamond like arrangement of the metal ions of the common super group Fddd-D/sub 2h//sup 4/. The results of i.r. and Raman spectroscopic measurements are reported and discussed in terms of the crystal structures. (author)

  9. Interaction between gaseous ozone and crystalline potassium bromide

    Science.gov (United States)

    Levanov, A. V.; Maksimov, I. B.; Isaikina, O. Ya.; Antipenko, E. E.; Lunin, V. V.

    2016-07-01

    The formation of nonvolatile products of the oxidation of a bromide ion during the interaction between gaseous ozone and powdered crystalline KBr is studied. It is found that potassium bromate KBrO3 is the main product of the reaction. The influence of major experimental factors (the duration of ozonation, the concentration of ozone, the humidity of the initial gas, and the temperature) on the rate of formation of bromate is studied. The effective constants of the formation of bromate during the interaction between O3 and Br- in a heterogeneous gas-solid body system and in a homogeneous aqueous solution are compared.

  10. OZONE CONTACTOR FLOW VISUALIZATION AND CHARACTERIZATION USING 3-DIMENSIONAL LASER INDUCED FLUORESCENCE

    Science.gov (United States)

    Hydrodynamics of ozone contactors have a crucial impact on efficient inactivation of pathogens such as Cryptosporidium as well as control of disinfection byproducts such as bromate. Improper mixing behaviors including short-circuiting, internal recirculation and presence...

  11. Catálise eletroquímica da redução do bromato em superfícies modificadas por filmes de molibdênio

    Directory of Open Access Journals (Sweden)

    Bertotti Mauro

    1998-01-01

    Full Text Available In this paper some studies concerning the electroreduction of Mo(VI in sulphuric acid solutions are described. We have shown that at suitable experimental conditions very stable molybdenum oxide films can be electrochemically deposited at glassy carbon electrodes, the reduction of bromate occurring at less negative potentials on the modified surface. Coulometric experiments have shown that bromide is not the only product of the catalytic bromate reduction by the molybdenum film and species like BrO2 may have part in this process. Based on chronoamperometric curves recorded at -0.60 V, analytical curves have been obtained for the reduction of bromate in the 0.1 - 0.8 mM range, a limit of detection of 20 µM for bromate being determined.

  12. Catálise eletroquímica da redução do bromato em superfícies modificadas por filmes de molibdênio

    OpenAIRE

    Bertotti Mauro; Pletcher Derek

    1998-01-01

    In this paper some studies concerning the electroreduction of Mo(VI) in sulphuric acid solutions are described. We have shown that at suitable experimental conditions very stable molybdenum oxide films can be electrochemically deposited at glassy carbon electrodes, the reduction of bromate occurring at less negative potentials on the modified surface. Coulometric experiments have shown that bromide is not the only product of the catalytic bromate reduction by the molybdenum film and species l...

  13. Determinação de bromato em melhoradores de farinha por cromatografia de troca iônica com detecção espectrofotométrica Bromate determination in flour improvers by ion exchange chromatography with spectrophotometric detection

    Directory of Open Access Journals (Sweden)

    Rogério Marcos Dallago

    2005-08-01

    Full Text Available KBrO3 is registered by the FAO/OMS as a genotoxic and carcinogenic compound. In spite of this, KBrO3 is still employed by Brazilian bakeries. Nowadays ion exchange chromatography (IEC is the most rapid and trustful method for BrO3- analysis. When at high concentrations, chloride ions can interfere in the BrO3- analysis, if the detection is performed by electrical conductivity. On the other hand, spectrophotometric detection, presented here is based on the absorption of BrO3- in the ultraviolet region (210 - 230 nm where the absortion of chloride ions is very low, thus making possible the qualitative and quantitative analysis of BrO3- in flour improver samples.

  14. Kinetic spectrophotometric determination of trace thallium(Ⅲ) based on the discoloring reaction of arsenazo M by oxidation of potassium bromate%溴酸钾氧化偶氮胂M褪色动力学光度法测定痕量铊(Ⅲ)

    Institute of Scientific and Technical Information of China (English)

    周之荣; 张纪文; 周瑜芬; 魏家文

    2006-01-01

    基于0.08 mol/LH2SO4介质中,痕量铊(Ⅲ)催化溴酸钾氧化偶氮胂M(AsAM)的褪色反应,建立了测定痕量铊(Ⅲ)的催化光度法.讨论了酸度、反应物浓度、反应温度、时间、干扰离子等因素的影响.研究了反应的最佳条件,并测定了一些动力学参数,催化反应的表观活化能为70.12kJ/mol.方法检出限为0.17μg/L,线性范围为0~20 μg/L.在25 mL溶液中,测定0.5μg铊(Ⅲ)的相对标准偏差为3.4%(n=11).结合溶剂萃取分离技术,用于测定废水及土壤样品中痕量铊(Ⅲ),回收率为97.0%~103.0%.

  15. 21 CFR 101.4 - Food; designation of ingredients.

    Science.gov (United States)

    2010-04-01

    ... ingredients of a wheat flour are declared in an ingredient statement, the principal ingredient of the flour... enriched flour, or self-rising flour is “flour”, “white flour”, “wheat flour”, or “plain flour”; the first... in the ingredient list of whole wheat flour, or bromated whole wheat flour......

  16. Ozone and hydrogen peroxide applications for disinfection by-products control in drinking water

    International Nuclear Information System (INIS)

    A great interest has been developed during the last years for ozone in drinking water treatments thanks to its strong oxidant and disinfectant power and for its efficiency in disinfection by-products (DBPs) precursors removal. However ozonization produces some specific DBPs, such as aldehydes and ketones; moreover, the presence of bromide in raw water engages ozone in a complex cycle in which both organic bromide and inorganic bromate are end products. In this paper the combination of hydrogen peroxide with ozone (known as peroxone process) and the ozone alone process were experimented on one surface water coming from the lake of Brugneto (Genova) in order to investigate bromate formation and trihalomethanes precursors removal during the oxidation process. The results show that the advanced peroxone process can be applied for bromate reduction (about 30-40%) with better results in comparison with the ozone alone process, while no advantages are shown for THMs precursors removal. The addition of in-line filtration step after pre-oxidation improves both bromate and THMs precursors removal, particularly with increasing hydrogen peroxide/ozone ratio in the oxidation step

  17. 9 CFR 113.408 - Avian mycoplasma antigen.

    Science.gov (United States)

    2010-01-01

    ... with 9 CFR 114.8. If phenol is used, a direct titration with a standardized bromide-bromate solution... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Avian mycoplasma antigen. 113.408... Diagnostics and Reagents § 113.408 Avian mycoplasma antigen. Mycoplasma antigens shall be prepared...

  18. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M

    2013-01-01

    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. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    Science.gov (United States)

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nav...

  20. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.; Schiltz, E.; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were al

  1. New considerations on hydrogen peroxide and related substances as food additives in view of carcinogenicity.

    Science.gov (United States)

    Ito, R

    1982-01-01

    The use of hydrogen peroxide as a labile and safe food preservative in fish cake and boiled noodles has recently been restricted by the Japanese government, since hyperplasia has been found in the duodenum of mice after long-term peroral study. The action of compounds with resembling mode of action, potassium bromate as an improving agent in bread, and sodium chlorate as a weed killer are discussed in this paper in view of developmental and environmental pharmacology. PMID:7078983

  2. Validação do método de determinação simultânea dos íons brometo e bromato por cromatografia iônica em águas de consumo humano

    OpenAIRE

    Gonçalves Maria Edite Pinto; Camões Maria Filomena; Paiva João Miguel; Benoliel Maria João; Carneiro Rui Neves

    2004-01-01

    European Directive (98/83/CE), compulsory after 2008, states that bromate in drinking water must be controlled at levels below 10 mg L-1. Supporting implementation of the Directive, the European Comission has established project SMT4-CT96 2134, in collaboration with various european institutions, aiming at the identification of the interferents to the current analytical method (Ionic Chromatography with Conductimetric Detection - IC/CD), their removal and the automation of pre-treatment and i...

  3. Effect of magnetic ion exchange and ozonation on disinfection by-product formation.

    Science.gov (United States)

    Kingsbury, Ryan S; Singer, Philip C

    2013-03-01

    The purpose of this research was to investigate the performance of treatment with magnetic ion exchange (MIEX) resin followed by ozonation in achieving disinfection goals while controlling bromate and chlorinated disinfection by-product (DBP) formation. Three water samples were collected from raw water supplies impacted by the San Francisco Bay Delta to represent the varying levels of bromide and total organic carbon (TOC) that occur throughout the year. A fourth water was prepared by spiking bromide into a portion of one of the samples. Samples of each water were pre-treated with alum or virgin MIEX resin, and the raw and treated waters were subsequently ozonated under semi-batch conditions to assess the impact of treatment on ozone demand, ozone exposure for disinfection ("CT"), and bromate formation. Finally, aliquots of raw, coagulated, resin-treated, and ozonated waters were chlorinated in order to measure trihalomethane formation potential (THMFP). In the waters studied, MIEX resin removed 41-68% of raw water TOC, compared to 12-44% for alum. MIEX resin also reduced the bromide concentration by 20-50%. The removal of TOC by alum and MIEX resin significantly reduced the ozone demand of all waters studied, resulting in higher dissolved ozone concentrations and CT values for a given amount of ozone transferred into solution. For a given level of disinfection (CT), the amount of bromate produced by ozonation of MIEX-treated waters was similar to or slightly less than that of raw water and significantly less than that of alum-treated water. MIEX resin removed 39-85% of THMFP compared to 16-56% removal by alum. Ozonation reduced THMFP by 35-45% in all cases. This work indicates that in bromide-rich waters in which ozone disinfection is used, MIEX resin is a more appropriate treatment than alum for the removal of organic carbon, as it achieves superior TOC and THM precursor removal and decreases the production of bromate from ozone. PMID:23286989

  4. Modélisation du procédé d'ozonation lors de la potabilisation des eaux - Application au contrôle des sous-produits de désinfection: du laboratoire à l'unité industrielle

    OpenAIRE

    Mandel, Pierre

    2010-01-01

    Facing major challenges, management of ozonation process will increasingly need prediction tools based on modelling. Dealing with different types of waters (chemistry) and different types of tanks (hydraulics), modelling of ozonation units has to adapt to site-specific conditions. The main objective of this work was to develop an integrated modelling procedure for industrial ozonation processes for predicting concentration profiles of: ozone, bromate and specific micropollutants. Two types of...

  5. An Investigation on Physical and Chemical Quality of Spring Waters

    Directory of Open Access Journals (Sweden)

    Fesem BAŞARI

    2010-12-01

    Full Text Available Objective: The aim of this study was to analyse the chemical and physical qualities of spring water coming to Water Chemistry Laboratory of Adana Hygiene Institute in 2009. The water quality parameters analysed were colour, flavor, odour, turbidity, conductivity, pH, iron, aluminum, boron, manganese, arsenic, ammonia, ozone and bromate. Method: The spring water samples coming to the laboratory, colour in 59 samples, flavor in 22 samples, odour in 57 samples, turbidity and bromate in 61 samples, pH in 63 samples, conductivity in 62 samples, aluminum and iron in 30 samples, boron in 15 samples, arsenic and manganese in 18 samples, ammonia in 60 samples, ozone in 48 samples were studied. ISO (International Organization for Standardization, DIN (Deutsches Institut für Normung, TS (Turkish Standard methods were used for study. The results evaluated according to criterion of ‘‘Regulation on the Quality of Water Intended for Human Comsumption’’.Results: As a result of physical analysis of spring water, turbidity was assigned in just two (%3,2 of 61 samples. pH and conductivity were studied in 63 and in 62 samples respectively and all the values were appropriate. Higher concentrations than the regulation limits were found for bromate in three samples (4,9 % of 61, and in one sample of respectively boron (6,7 % out of 15, manganese (5,6 % out of 18 and arsenic (5,6% out of 18. Aluminum, ammonia, iron and ozone values in the analized samples were not found over the limits.Conclusion: Being found of bromate rates high was related to ozonize. And found of boron, manganese and arsenic was a symptom of dangerous pollution in terms of health. So, spring water pollution control essential for public health.

  6. Utilization of a Green Brominating Agent for the Spectrophotometric Determination of Pipazethate HCl in Pure Form and Pharmaceutical Preparations

    OpenAIRE

    Ayman A. Gouda

    2013-01-01

    Five simple, accurate, and sensitive spectrophotometric methods (A–E) have been described for the indirect assay of pipazethate HCl (PZT) either in pure form or in pharmaceutical preparations. The proposed methods are based on the bromination of pipazethate HCl with a solution of excess bromate-bromide mixture in hydrochloric acid medium and subsequent estimation of the residual bromine by different reaction schemes. In the first three methods (A–C), the determination of the residual bromine ...

  7. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    OpenAIRE

    Wolterink, A.F.W.M.; Schiltz, E; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  8. Characterisation of chlorate reduction in the haloarchaeon Haloferax mediterranei

    OpenAIRE

    Martínez Espinosa, Rosa María; Richardson, David J.; Bonete Pérez, María José

    2015-01-01

    Background: Haloferax mediterranei is a denitrifying haloarchaeon using nitrate as a respiratory electron acceptor under anaerobic conditions in a reaction catalysed by pNarGH. Other ions such as bromate, perchlorate and chlorate can also be reduced. Methods: Hfx. mediterranei cells were grown anaerobically with nitrate as electron acceptor and chlorate reductase activity measured in whole cells and purified nitrate reductase. Results: No genes encoding (per)chlorate reductases have been dete...

  9. Characterization of the Chlorate Reductase from Pseudomonas chloritidismutans

    OpenAIRE

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  10. O-Anisidine as Indicator in Titrimetric Determination of Ascorbic Acid and Isonicotinic Acid Hydrazide in Pharmaceutical Formulations

    OpenAIRE

    Andrews, B. S. A.; B.Sreenivas Rao; Som Shankar Dubey; B.Venkata Kiran

    2010-01-01

    Inspite of the beautiful red coloured oxidized product of O-anisidine, the studies on its application in analytical techniques are scanty. So, authors have taken up the investigation on the utility of O-anisidine as a new Analytical reagent in the bromatometric-Indicator reaction. The detailed reaction on the potassium bromate and OAnisidine has enabled the authors to utilize O-Anisidine in titration of Ascorbic Acid and Isonicitonic Acid Hydrazide. Suitable conditions has been established wi...

  11. ERK Oscillation-Dependent Gene Expression Patterns and Deregulation by Stress-Response

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Katrina M.; Cummings, Brian S.; Shankaran, Harish; Scholpa, Natalie E.; Weber, Thomas J.

    2014-09-15

    Studies were undertaken to determine whether ERK oscillations regulate a unique subset of genes in human keratinocytes and subsequently, whether the p38 stress response inhibits ERK oscillations. A DNA microarray identified many genes that were unique to ERK oscillations, and network reconstruction predicted an important role for the mediator complex subunit 1 (MED1) node in mediating ERK oscillation-dependent gene expression. Increased ERK-dependent phosphorylation of MED1 was observed in oscillating cells compared to non-oscillating counterparts as validation. Treatment of keratinocytes with a p38 inhibitor (SB203580) increased ERK oscillation amplitudes and MED1 and phospho-MED1 protein levels. Bromate is a probable human carcinogen that activates p38. Bromate inhibited ERK oscillations in human keratinocytes and JB6 cells and induced an increase in phospho-p38 and decrease in phospho-MED1 protein levels. Treatment of normal rat kidney cells and primary salivary gland epithelial cells with bromate decreased phospho-MED1 levels in a reversible fashion upon treatment with p38 inhibitors (SB202190; SB203580). Our results indicate that oscillatory behavior in the ERK pathway alters homeostatic gene regulation patterns and that the cellular response to perturbation may manifest differently in oscillating vs non-oscillating cells.

  12. The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

    Directory of Open Access Journals (Sweden)

    Glòria Carrasco-Turigas

    2013-01-01

    Full Text Available Disinfection by-products (DBPs are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4 (chloroform (TCM, bromodichloromethane (BDCM, dibromochloromethane (DBCM, and bromoform (TBM, MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97% and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.

  13. Process analysis and economics of drinking water production from coastal aquifers containing chromophoric dissolved organic matter and bromide using nanofiltration and ozonation.

    Science.gov (United States)

    Sobhani, R; McVicker, R; Spangenberg, C; Rosso, D

    2012-01-01

    In regions characterized by water scarcity, such as coastal Southern California, groundwater containing chromophoric dissolved organic matter is a viable source of water supply. In the coastal aquifer of Orange County in California, seawater intrusion driven by coastal groundwater pumping increased the concentration of bromide in extracted groundwater from 0.4 mg l⁻¹ in 2000 to over 0.8 mg l⁻¹ in 2004. Bromide, a precursor to bromate formation is regulated by USEPA and the California Department of Health as a potential carcinogen and therefore must be reduced to a level below 10 μg l⁻¹. This paper compares two processes for treatment of highly coloured groundwater: nanofiltration and ozone injection coupled with biologically activated carbon. The requirement for bromate removal decreased the water production in the ozonation process to compensate for increased maintenance requirements, and required the adoption of catalytic carbon with associated increase in capital and operating costs per unit volume. However, due to the absence of oxidant addition in nanofiltration processes, this process is not affected by bromide. We performed a process analysis and a comparative economic analysis of capital and operating costs for both technologies. Our results show that for the case studied in coastal Southern California, nanofiltration has higher throughput and lower specific capital and operating cost, when compared to ozone injection with biologically activate carbon. Ozone injection with biologically activated carbon, compared to nanofiltration, has 14% higher capital cost and 12% higher operating costs per unit water produced while operating at the initial throughput. Due to reduced ozone concentration required to accommodate for bromate reduction, the ozonation process throughput is reduced and the actual cost increase (per unit water produced) is 68% higher for capital cost and 30% higher for operations. PMID:22054587

  14. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Romaris-Hortas, Vanessa; Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. 15782 - Santiago de Compostela (Spain); Moreda-Pineiro, Jorge [Department of Analytical Chemistry, Faculty of Sciences, University of A Coruna, Campus da Zapateira, s/n. 15071, A Coruna (Spain); Moreda-Pineiro, Antonio, E-mail: antonio.moreda@usc.es [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. 15782 - Santiago de Compostela (Spain)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Bioavailable iodine and bromine speciation in edible seaweed were developed. Black-Right-Pointing-Pointer In vitro dialyzability was used to assess the bioavailable fractions. Black-Right-Pointing-Pointer AEC hyphenated with inductively coupled plasma-mass spectrometry was used. Black-Right-Pointing-Pointer Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. Black-Right-Pointing-Pointer Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5-1.5 mL min{sup -1} range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine ({sup 127}I) and bromine ({sup 79}Br). Low dialyzability ratios (within the 2.0-18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  15. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: ► Bioavailable iodine and bromine speciation in edible seaweed were developed. ► In vitro dialyzability was used to assess the bioavailable fractions. ► AEC hyphenated with inductively coupled plasma-mass spectrometry was used. ► Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. ► Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5–1.5 mL min−1 range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine (127I) and bromine (79Br). Low dialyzability ratios (within the 2.0–18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  16. Renal deterioration caused by carcinogens as a consequence of free radical mediated tissue damage: a review of the protective action of melatonin.

    Science.gov (United States)

    Gultekin, Fatih; Hicyilmaz, Hicran

    2007-10-01

    This brief review summarizes some of the publications that document the preventive role of melatonin in kidney damage caused by carcinogens such as 2-nitropropane, arsenic, carbon tetrachloride, nitrilotriacetic acid and potassium bromate. Numerous chemicals generate excessive free radicals that eventually induce renal worsening. Melatonin partially or totally prevents free radical mediated tissue damages induced by many carcinogens. Protective actions of melatonin against the harmful effects of carcinogens are believed to stem from its direct free radical scavenging and indirect antioxidant activities. Dietary or pharmacologically given melatonin may attenuate the oxidative stress, thereby mitigating the subsequent renal damage. PMID:17823789

  17. Renal deterioration caused by carcinogens as a consequence of free radical mediated tissue damage: a review of the protective action of melatonin

    Energy Technology Data Exchange (ETDEWEB)

    Gultekin, Fatih; Hicyilmaz, Hicran [Suleyman Demirel University, School of Medicine, Department of Biochemistry, Isparta (Turkey)

    2007-10-15

    This brief review summarizes some of the publications that document the preventive role of melatonin in kidney damage caused by carcinogens such as 2-nitropropane, arsenic, carbon tetrachloride, nitrilotriacetic acid and potassium bromate. Numerous chemicals generate excessive free radicals that eventually induce renal worsening. Melatonin partially or totally prevents free radical mediated tissue damages induced by many carcinogens. Protective actions of melatonin against the harmful effects of carcinogens are believed to stem from its direct free radical scavenging and indirect antioxidant activities. Dietary or pharmacologically given melatonin may attenuate the oxidative stress, thereby mitigating the subsequent renal damage. (orig.)

  18. Association between age and repair of oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise;

    2015-01-01

    damaged DNA in peripheral blood mononuclear cells (PBMCs). We isolated PBMCs from subjects aged 18-83 years, as part of a health survey of the Danish population that focussed on lifestyle factors. The level of DNA repair activity was measured as incisions on potassium bromate-damaged DNA by the comet...... assay. There was an inverse association between age and DNA repair activity with a 0.65% decline in activity per year from age 18 to 83 (95% confidence interval: 0.16-1.14% per year). Univariate regression analysis also indicated inverse associations between DNA repair activity and waist-hip ratio (P...

  19. Kinetic Spectrophotometric Determination of Morphine in Pharmaceutical Samples

    Directory of Open Access Journals (Sweden)

    Mohsen Keyvanfard

    2014-12-01

    Full Text Available Anew,sensitive, simple, inexpensive and fast kinetic spectrophotometric method was developed for the determination of trace amounts of morphine over the range of 12-60 ng/mL. The method is based on the catalytic effect of morphine on the reaction of bromate and methylene bluein acidic media is reported. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of methylene blue at 665 nm with a fixed-time 0.5-2.5 min from initiation

  20. EFFECTS STUDY OF NIGELLA SATIVA, ITS OIL AND THEIR COMBINATION WITH VITAMIN E ON OXIDATIVE STRESS IN RATS

    OpenAIRE

    Amr A. Rezq

    2014-01-01

    Antioxidants or free radical scavengers are very important in protecting the living cells against any damage induced by free radicals. The effects of Nigella Sativa Extract (NSE), Nigella Sativa Oil (NSO) and Vitamin E (Vit. E) and the combination of NSE or NSO with Vit. E on potassium bromate (KBrO3)-induced oxidative stress in male rats were investigated. Forty nine Sprague Dawley male rats were weighingv 185±5 g and 10-12 weeks old were used to achieve the pre...

  1. Evaluation of the sensitivity of three sublethal cytotoxicity assays in human HepG2 cell line using water contaminants

    OpenAIRE

    Jondeau, Adeline; DAHBI, Laurence; Bani-Estivals, Marie-Helene; Chagnon, Marie-Christine

    2006-01-01

    The in vitro toxicological index IC50 (the millimolar concentration of compound which inhibits response assay by 50% compared to the solvent control) of 11 water contaminants (acrylamide, atrazine, B[a]P, BPA, 2,4-DAT, 17-alphaEE, H(2)O(2), 4-OP, sodium bromate, sodium chlorate, sodium nitrate) was evaluated on the human hepatoma (HepG2) cells using three short-term bioassays related to their morbidity status [radiometric RNA synthesis assay (RNA), luminometric ATP assay (ATP), fluorometric A...

  2. ESTERIFICATION OF ACRYLIC ACID WITH 1-BUTANOL IN LIQUID PHASE CATALYZED WITH AL-MCM-41

    OpenAIRE

    Edson Avellaneda Maytán; Gustavo Paim Valença

    2010-01-01

    This work studies the esterification of acrylic acid with 1-butanol using Al-MCM-41 as catalyst with different degrees of acidity at different temperatures. Al-MCM-41 synthesis was made from bromate Cetyl trimethyl ammonium using as router agent, NH4OH (25%), deionized H2O and Al2(SO4)3. Catalytic tests were carried out by groups and worked with temperature ranges among (333 to 348) K and a small sample was collected at predetermined intervals of time for subsequent gas chromatography analysi...

  3. Copper(I) Bromide: An Alternative Emitter for Blue-Colored Flame Pyrotechnics.

    Science.gov (United States)

    Juknelevicius, Dominykas; Karvinen, Eero; Klapötke, Thomas M; Kubilius, Rytis; Ramanavicius, Arunas; Rusan, Magdalena

    2015-10-19

    Copper(I) bromide was evaluated as an alternative emitter for blue flame pyrotechnic compositions. CuBr and CuCl emission spectra were recorded from a butane torch flame and compared. Cu(BrO3 )2 was synthesized and used in pyrotechnic compositions as an oxidizer and the source for the generation of CuBr species. Pyrotechnic compositions, which contained copper and potassium bromates as oxidizers, were optimized for the generation of blue flames. The experimental data, including emission spectra of the flames, chromaticity coordinates, burning rates, luminous intensities, and sensitivity tests, were analyzed and compared. PMID:26471445

  4. Ultra-trace analysis of nitrite in food samples by flow injection with spectrophotometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Ensafi, A.A.; Bagherian Dehaghei, G. [College of Chemistry, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    1999-01-01

    A flow injection system with spectrophotometric detection is proposed for the determination of low levels of nitrite based on its catalytic effect on the oxidation of gallocyanine by bromate in acidic media. Various analytical parameters such as acidity, reagent concentration, flow rate, sample size, time, temperature, and interfering species were studied. The calibration graph was linear for 0.020-0.500 {mu}g/mL of nitrite. The method is successfully applied to food samples. Up to 30 {+-} 5 samples can be analyzed per hour. (orig.) With 3 figs., 3 tabs., 17 refs.

  5. Removal of micro-pollutants from drinking water with advanced oxidation processes

    OpenAIRE

    Sander, Fabian

    2009-01-01

    This thesis determines the feasibility of ozone gas and ultraviolet (UV)technologies to reduce pollutants from drinking water. The merging of both techniques, ozone and UV, is known as a so called advanced oxidation process (AOP). ITT Wedeco is developing new technologies to meet the growing concern of water works to remove micro-pollutants from their water. The emphasis of this work was put on the formation of the oxidation by-product bromate and the removal of the solvent 1.4 dioxane fr...

  6. Catalytic spectrophotometric determination of trace selenium in microemulsion after separation and enrichment by SDG

    Institute of Scientific and Technical Information of China (English)

    LI Huizhi; ZHAI Diantang; FAN Yingju

    2006-01-01

    A new catalytic spectrophotometric method was developed for the determination of trace amount of Se(Ⅳ) in microemulsion medium. The method is based on the catalytic effect of traces of Se(Ⅳ) on the oxidation of2',4'-dichlorophenylfluorone (p-CPF) by potassium bromate with HNO3 as an activator in the presence of nonionic microemulsion medium. Under optimum conditions, the calibration graph is linear in the range of 0.4-15 μg. L-1 of Se(Ⅳ) atseparated and enriched by sulphydryl dextrane gel (SDG). The method has been applied for determination of trace selenium with satisfactory results.

  7. Optimized removal of dissolved organic carbon and trace organic contaminants during combined ozonation and artificial groundwater recharge.

    Science.gov (United States)

    Hübner, U; Miehe, U; Jekel, M

    2012-11-15

    Pilot scale experiments using an 8 g/h ozonation unit and a 1.4 m(2) slow sand filter have demonstrated that the combination of ozonation and artificial groundwater recharge is suitable for efficient reduction of bulk and trace organics. The biodegradation of dissolved organic carbon (DOC) in the slow sand filter was enhanced from 22% without pre-treatment to 34% by pre-ozonation. In addition, realistic surface water concentrations of most investigated trace organic compounds (TrOCs) including carbamazepine, sulfamethoxazole, phenazone and metoprolol were reduced below the limits of quantification. Only a few TrOCs, e.g. primidone and benzotriazole, were not efficiently removed in both treatment steps and could be detected regularly in the filter effluent. For these compounds, enhanced treatment, such as advanced oxidation processes, needs to be considered. Testing for genotoxicity and cytotoxicity did not reveal any systematic adverse effects for human health. The formation of the by-product bromate from bromide was below the limit of the German drinking water directive of 10 μg/L. No removal of bromate was observed in the aerobic slow sand filter. Additional experiments with sand columns showed that operating a preceding bank filtration step to reduce DOC can reduce oxidant demand by approximately 20%. PMID:23014565

  8. Second-order advantage from kinetic-spectroscopic data matrices in the presence of extreme spectral overlapping

    Energy Technology Data Exchange (ETDEWEB)

    Culzoni, Maria J. [Laboratorio de Desarrollo Analitico y Quimiometria (LADAQ), Catedra de Quimica Analitica I, Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria, Santa Fe S3000ZAA (Argentina); Goicoechea, Hector C. [Laboratorio de Desarrollo Analitico y Quimiometria (LADAQ), Catedra de Quimica Analitica I, Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria, Santa Fe S3000ZAA (Argentina)], E-mail: hgoico@fbcb.unl.edu.ar; Ibanez, Gabriela A.; Lozano, Valeria A. [Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario and Instituto de Quimica Rosario (IQUIR-CONICET), Suipacha 531, Rosario S2002LRK (Argentina); Marsili, Nilda R. [Laboratorio de Desarrollo Analitico y Quimiometria (LADAQ), Catedra de Quimica Analitica I, Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria, Santa Fe S3000ZAA (Argentina); Olivieri, Alejandro C. [Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario and Instituto de Quimica Rosario (IQUIR-CONICET), Suipacha 531, Rosario S2002LRK (Argentina)], E-mail: aolivier@fbioyf.unr.edu.ar; Pagani, Ariana P. [Departamento de Quimica Analitica, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario and Instituto de Quimica Rosario (IQUIR-CONICET), Suipacha 531, Rosario S2002LRK (Argentina)

    2008-04-28

    Multivariate curve resolution coupled to alternating least-squares (MCR-ALS) has been employed to model kinetic-spectroscopic second-order data, with focus on the achievement of the important second-order advantage, under conditions of extreme spectral overlapping among sample components. A series of simulated examples shows that MCR-ALS can conveniently handle the studied analytical problem unlike other second-order multivariate calibration algorithms, provided matrix augmentation is implemented in the spectral mode instead of in the usual kinetic mode. The approach has also been applied to three experimental examples, which involve the determination of: (1) the antiparkinsonian carbidopa (analyte) in the presence of levodopa as a potential interferent, both reacting with cerium (IV) to produce the fluorescent species cerium (III) with different kinetics; (2) Fe(II) (analyte) in the presence of the interferent Zn(II), both catalyzing the oxidation of methyl orange with potassium bromate; and (3) tartrazine (analyte) in the presence of the interferent brilliant blue, both oxidized with potassium bromate, with the interferent leading to a product with an absorption spectrum very similar to tartrazine. The results indicate good analytical performance towards the analytes, despite the intense spectral overlapping and the presence of unexpected constituents in the test samples.

  9. Kinetic spectrophotometric determination of trace amounts of selenium and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Safavi, A.; Sedghy, H.R.; Shams, E. [Dept. of Chemistry, Shiraz Univ. (Iran)

    1999-11-01

    A sensitive kinetic spectrophotometric method has been developed for the determination of Se(IV) over the range of 45 to 4000 ng in 10 mL of solution. The method is based on the catalytic effect of Se(IV) on the reduction reaction of bromate by hydrazinium dichloride, with subsequent reaction of Ponceau S with products of the above reaction (chlorine and bromine), causing color changing of Ponceau S. Method development includes optimization of time interval for measurement of slope, pH, reagents concentration, and temperature. The optimized conditions yielded a theoretical detection limit of 33 ng/10 mL of solution of Se(IV). The interfering effects were studied and removed. The method was applied to the determination of selenium in spiked water, Kjeldahl tablet, selenium tablet, and shampoo. Vanadium(V) has an inhibition effect on the catalyzed reaction of bromate and hydrazine by selenium. Using this effect, V(V) can be determined in the range of 70 to 2500 ng in 10 mL of solution. The optimization procedure includes pH and selenium concentration. An extraction method was used for interference removal. The method was applied to the determination of vanadium in petroleum. (orig.)

  10. UV-based advanced oxidation processes for the treatment of odour compounds: efficiency and by-product formation.

    Science.gov (United States)

    Zoschke, Kristin; Dietrich, Norman; Börnick, Hilmar; Worch, Eckhard

    2012-10-15

    The occurrence of the taste and odour compounds geosmin and 2-methyl isoborneol (2-MIB) affects the organoleptic quality of raw waters from drinking water reservoirs worldwide. UV-based oxidation processes for the removal of these substances are an alternative to adsorption and biological processes, since they additionally provide disinfection of the raw water. We could show that the concentration of geosmin and 2-MIB could be reduced by VUV irradiation and the combination of UV irradiation with ozone and hydrogen peroxide in pure water and water from a drinking water reservoir. The figure of merit EE/O is an appropriate tool to compare the AOPs and showed that VUV and UV/O(3) yielded the lowest treatment costs for the odour compounds in pure and raw water, respectively. Additionally, VUV irradiation with addition of ozone, generated by the VUV lamp, was evaluated. The generation of ozone and the irradiation were performed in a single reactor system using the same low-pressure mercury lamp, thereby reducing the energy consumption of the treatment process. The formation of the undesired by-products nitrite and bromate was investigated. The combination of VUV irradiation with ozone produced by a VUV lamp avoided the formation of relevant concentrations of the by-products. The internal generation of ozone is capable to produce ozone concentrations sufficient to reduce EE/O below 1 kWh m(-3) and without the risk of the formation of nitrite or bromate above the maximum contaminant level. PMID:22858230

  11. Synthesis of α-Bromine- Terminated Polystyrene Macroinitiator and Its Initiation of MMA Polymerization by ATRP

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present paper the synthesis of block copolymers via the transformation from living anionic polymerization (LAP) to atom transfer radical polymerization (ATRP) was described. Α-Bromine-terminated polystyrenes(PStBr) in the LAP step was prepared by using n-BuLi as initiator, tetrahydrofuran (THF) as the activator, α-methylstyrene (α-MeSt) as the capping group and liquid bromine (Br2) as the bromating agent. The effects of reaction conditions such as the amounts of α-MeSt, THF, and Br2 as well as molecular weight of polystyrene on the bromating efficiency (BE) and coupling extent (CE) were examined. The present results show that the yield of PStBr obtained was more than 93.8% and the coupling reaction was substantially absent. PStBr was further used as the macroinitiator in the polymerization of methyl-methacrylate(MMA) in the presence of copper(Ⅰ) halogen and 2,2-bipyridine(bpy) complexes. It was found that the molecular weight of the resulted PSt-b-PMMA increased linearly with the increase of the conversion of MMA and the polydispersity was 1.2-1.6. The structures of PStBr and P(St-b-MMA) were characterized by 1H NMR spectra.

  12. Green synthesis of 5-bromo-vanillin%5-溴香兰素的绿色合成

    Institute of Scientific and Technical Information of China (English)

    彭安顺; 英荣建

    2009-01-01

    以冰醋酸为溶剂,香兰素为原料,AlBr3为催化剂,HBrO3与KBrO3为溴化剂合成了5-溴香兰素.采用正交实验法考察了影响收率的因素.最佳条件为:香兰素、KBrO3与AlBr3的物质的量的摩尔比为1:0.5:0.056,反应时间6.0h,反应温度30℃.在优化条件下收率可达90.4%.产物结构通过IR、1HNMR、熔点测定和元素分析得以确认.%5-bromo-vanillin was synthesizedby using vanillin as raw material,aluminium chloride as catalyst, hydrobromic acid and potassium bromate as brominating agent and acetic acid as solvent.Factors influencing the yield were investigated by the orthogonal experimental method.The optimum conditions are as follows:Vanillin: potassium bromate:aluminium chloride is 1mol:0.5mol:0.056mol, reaction time is 6.0h,reaction temperature is 30%. The yield is above 90.4% under the optimum conditions. The title compound was characterized by IR,1H NMR,mp. Measurement and element analysis.

  13. 3-溴-4-羟基-5-甲氧基苯甲酸甲酯的合成%Synthesis of 3-bromo-4-hydroxy-5-methoxy-benzoic Acid Methyl Ester

    Institute of Scientific and Technical Information of China (English)

    闫慧丽; 张立新; 张慧芳; 马甲民

    2011-01-01

    以香兰素为主要原料,经溴水溴代得溴代香兰素,再经氧化银氧化制取溴代香兰酸,最后与甲醇发生酯化反应,成功制得3-溴-4-羟基-5-甲氧基苯甲酸甲酯,总收率66.4%.各步反应的生成物提纯后经过1H-NMR、IR进行表征.%3-bromo4-hydroxy-5-methoxy-benzoic acid methyl ester in total yield of 66.4% is synthesized from vanillin via bromation by bromide, oxidation over silver oxide and esterification with methanol.The products from different steps are identified by 1H-NMR and IR.

  14. Electrochemical removal of bromide and reduction of THM formation potential in drinking water.

    Science.gov (United States)

    Kimbrough, David Eugene; Suffet, I H

    2002-11-01

    Trihalomethanes (THMs), a by-product of the chlorination of natural waters containing dissolved organic carbon and bromide, are the focus of considerable public health concern and regulation due to their potential as a carcinogen by ingestion. This paper presents a promising new water treatment process that lowers the concentration of bromide in drinking water and thus, lowers the THM formation potential. Bromide is oxidized by electrolysis to bromine and then the bromine apparently volatilized. The electrolyzed water, when chlorinated, produces measurably lower amounts of THMs and proportionately fewer brominated THMs, which are of greater public health concern than the chlorinated THMs. Removing bromide should also reduce the formation of other disinfection by-products such as bromate and haloacetic acids. PMID:12448534

  15. Debromination and decomposition of bromoform by contact glow discharge electrolysis in an aqueous solution

    International Nuclear Information System (INIS)

    Bromoform (BF) is a stable and carcinogenic contaminant in water. In this study, efficient debromination and decomposition of BF induced by contact glow discharge electrolysis (CGDE) in a sodium sulfate solution were investigated. Intermediate byproducts were determined by ionic chromatography and gas chromatography, respectively. Experimental results showed that alkaline conditions and additions of organic additives to the solution were favorable for both the removal and the debromination of BF. Oxalic acid, formic acid, dibromomethane and bromate ion were determined as the major intermediate byproducts. Final products were inorganic carbon and bromide ion. Hydrated electrons may be the most likely active species responsible for the initiation of the debromination, and hydroxyl radicals may be the ones for the oxidation of the intermediate byproducts

  16. A fixed cations and low Tg polymer: the poly(4-vinyl-pyridine) quaternized by poly(ethylene oxide) links. Conductivity study; Un electrolyte polymere a cations fixes et bas Tg: les poly(4-vinylpyridine) quaternisees par des chainons de poly(oxyde d`ethylene). Etude de la conductivite

    Energy Technology Data Exchange (ETDEWEB)

    Gramain, Ph. [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Frere, Y. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Institut Charles Sadron

    1996-12-31

    The spontaneous ionic polymerization of 4-vinyl-pyridine in presence of mono-tosylated or bromated short chains of poly(ethylene oxide)-(PEO) is used to prepare amorphous comb-like poly-cations with low Tg. The polymer electrolyte properties of these new structures have been studied without any addition of salts. The ionic conductivity of these fixed cation poly-electrolytes depends on the length of the grafted PEO and varies from 10{sup -7} to 10{sup -4} S/cm between 25 and 80 deg. C. It is only weakly dependent on the nature of the cation but it is controlled by the movements of the pyridinium cation which are facilitated by the plastifying effect of the POE chains which do not directly participate to the ionic transport. (J.S.) 17 refs.

  17. Preconcentration of trace amounts of formaldehyde from water, biological and food samples using an efficient nanosized solid phase, and its determination by a novel kinetic method

    International Nuclear Information System (INIS)

    This work presents a sensitive method for the determination of formaldehyde. It is based on the use of modified alumina nanoparticles for its preconcentration, this followed by a new and simple catalytic kinetic method for its determination. Alumina nanoparticles were chemically modified by immobilization of 2,4-dinitrophenylhydrazine via sodium dodecyl sulfate as a surfactant. The formaldehyde retained on the modified adsorbent was then desorbed and determined via its catalytic effect on the oxidation of thionine by bromate ion. Factors affecting the preconcentration and determination of formaldehyde have been investigated. Formaldehyde can be detected in the range from 0. 05 to 38. 75 μg L-1, and no serious interferences have been observed. The method has been successfully applied to the quantitation of formaldehyde in water, food, and certain biological samples. (author)

  18. Analytical method used for intermediate products in continuous distillation of furfural

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.L.; Jia, M.; Wang, L.J.; Deng, Y.X.

    1981-01-01

    During distillation of furfural, analysis of main components in the crude furfural condensate and intermediate products is very important. Since furfural and methylfurfural are homologous and both furfural and acetone contain a carbonyl group, components in the sample must be separated before analysis. An improved analytical method has been studied, the accuracy and precision of which would meet the requirement of industrial standards. The analytical procedure was provided as follows: to determine the furfural content with gravimetric method of barbituric acid; to determine the methanol content with dichromate method after precipitating furfural and acetone, and distilling the liquid for analysis; and to determine the methylfurfural content with bromide-bromate method, which can be used only in the sample containing higher content of methylfurfural. For the sample in low content, the gas-liquid chromatographic method can be used. 7 references.

  19. PIXE analysis of Nigerian flour and bread samples

    Science.gov (United States)

    Olise, Felix S.; Fernandes, Adriana M.; Cristina Chaves, P.; Taborda, Ana; Reis, Miguel A.

    2014-01-01

    The alleged use of potassium bromate (KBrO3) in bread baking led a few authors to report on the chemical methods for the determination of KBrO3 levels in bread. In order to examine the potentials of a non chemical particle induced X-ray emission (PIXE) method for this purpose, six sets of samples, each composed of flour, dough and bread from a production batch were analysed. The samples were obtained from six different bakers of bread at Ile-Ife, Nigeria. The flour samples were air-dried while others were freeze dried at about -16 °C. The samples were homogenised in an agate mortar and then pelletised. Samples were analysed at the CTN standard PIXE setup and standard procedures for thick target samples analysis were followed. In some samples significant concentrations of bromine were found. In the present work we present possible explanations for the presence of this potentially dangerous contaminant in the samples.

  20. O-Anisidine as Indicator in Titrimetric Determination of Ascorbic Acid and Isonicotinic Acid Hydrazide in Pharmaceutical Formulations

    Directory of Open Access Journals (Sweden)

    B.S.A.Andrews

    2010-10-01

    Full Text Available Inspite of the beautiful red coloured oxidized product of O-anisidine, the studies on its application in analytical techniques are scanty. So, authors have taken up the investigation on the utility of O-anisidine as a new Analytical reagent in the bromatometric-Indicator reaction. The detailed reaction on the potassium bromate and OAnisidine has enabled the authors to utilize O-Anisidine in titration of Ascorbic Acid and Isonicitonic Acid Hydrazide. Suitable conditions has been established with different acids viz., hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid to give sharp colour change at the equivalence point. The present method has been applied for the estimation of Ascorbic acid and also Isonicitonic Acid Hydrazide in pharmaceutical formulations and results obtained are in good agreement with the values obtained by standard methods

  1. Catalytic determination of ultra trace amounts of vanadium with detection by linear sweep voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Ensafi, Ali A. [College of Chemistry, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Naderi, B. [College of Chemistry, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    1997-06-01

    Vanadium has a very strong catalytic effect on the bromate oxidation of gallocyanine at pH of 4.0. The oxidation product of gallocyanine exhibit a voltammetric wave at + 0.10 V vs. Ag/AgCl reference electrode in 0.10 mol/l KNO{sub 3} medium. The linear scan voltammetric behaviour of the reaction products at HMDE has been studied and selected as the indicator component for the reaction. A detection limit of 0.05 ng/ml and calibration graph from 0.30-200.00 ng/ml vanadium were obtained. Vanadium in water and gasoline samples was determined by this method, with satisfactory results. (orig.). With 5 figs., 2 tabs.

  2. Kinetic Determination of Uric Acid in Human Serum by Using the Uncatalyzed BZ Reaction in Non-equilibrium Steady State

    Institute of Scientific and Technical Information of China (English)

    Ren, Jie; Yang, Wu; Niu, Xiuli; Gao, Jinzhang

    2012-01-01

    A novel kinetic method for determination of uric acid in human serum by means of an uncatalyzed BZ system consisting of potassium bromate and p-hydroxybenzaldehyde (p-HBA) in sulfuric acid medium was proposed, in which the analyte perturbation to the system was recorded close to the bifurcation point. The potential change was directly proportional to the logarithm of concentration of uric acid in the range of 3.73 × 10 8--7.48 × 10-4 mol.L-1 (r=0.9983) with a detection limit of 7.45 × 10-9mol.L-I and a recovery from 98.9% to 101.1%. A comparison between the proposed technique and other methods indicated that results obtained were in agreement with those in clinical detection. In addition, the possible mechanism of action of uric acid on the uncatalyzed BZ reaction was also discussed briefly.

  3. Kinetic spectrophotometric determination of bromide in clidinium-c drug

    Institute of Scientific and Technical Information of China (English)

    Ali Sheibani; M. Reza Shishehbore; Zahra Tavakolian Ardakani

    2011-01-01

    A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide. The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media. The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm. Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL. The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively. The influence of potential interfering ions and substances was studied. The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.

  4. Application of biofiltration system on AOC removal: column and field studies.

    Science.gov (United States)

    Chien, C C; Kao, C M; Chen, C W; Dong, C D; Wu, C Y

    2008-04-01

    The Cheng-Ching Lake Water Treatment Plant (CCLWTP) is the main supplier of domestic water for the Greater Kaohsiung area, the second largest metropolis in Taiwan. Biological activated carbon (BAC) filtration is one of the major treatment processes in CCLWTP. The objectives of this study were to evaluate the effectiveness of BAC filtration on water treatment in the studied advanced water treatment plant and its capability on pollutants [e.g., AOC (assimilable organic carbon), bromide, bromate, iron] removal. In this study, water samples from each treatment process of CCLWTP were collected and analyzed periodically to assess the variations in concentrations of AOC and other water quality indicators after each treatment unit. Moreover, the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers was also evaluated through a column experiment. Results show that the removal efficiencies for AOC, bromide, bromate, and iron are 86% 100%, 17%, and 30% after the BAC filter bed, respectively. This indicates that BAC filtration plays an important role in pollutant removal. Results also show that AOC concentrations in raw water and effluent of the CCLWTP are approximately 143 and 16 microg acetate-Cl(-1), respectively. This reveals that the treatment processes applied in CCLWTP is able to remove AOC effectively. Results of column study show that the AOC removal efficiencies in the GAC and anthracite columns are 60% and 17%, respectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic images. The observed microorganisms included bacteria (rods, cocci, and filamentous bacteria), fungi, and protozoa. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement. PMID:18294674

  5. Feasibility of wavelength dispersive X-ray fluorescence spectrometry for a simplified analysis of bromine in water samples with the aid of a strong anion exchange disk

    International Nuclear Information System (INIS)

    The feasibility of wavelength dispersive X-ray fluorescence spectrometry (WDXRF) for a simplified analysis of bromine (Br) in water samples with the aid of strong anion exchange (SAX) disk was assessed in this study. Dissolved Br in the water sample was pre-concentrated on the SAX disk and directly analyzed by WDXRF without an elution step. The SAX disk was capable of fully adsorbing both bromide (Br−) and bromate (BrO3−) on its surface owing to their anionic properties, regardless of the pH level of environmental samples. The SAX–WDXRF system was examined using calibration standards (i.e., SAX disks with specific amounts of Br retained; 1, 10, 50, 100 and 500 μg), and a determination coefficient of R2 = 0.9999 was yielded. The system had a low detection limit for Br (limit of detection = 0.253 μg for Br on the SAX disk) with good reproducibility (relative standard error (RSE) = 4–7%). Spike and inter-comparison tests were performed to confirm the accuracy of the proposed SAX–WDXRF method. Both tests exhibited reasonable accuracy (RSE = 3–6%). The method is simple and easy, indicating a great possibility of application in various environmental sample types, especially for which a simplified analytical system for the determination of Br is urgently required. - Highlights: • Bromide and bromate were entirely retained on a strong anion exchange (SAX) disk. • The SAX disk was used to pre-concentrate dissolved Br species from water samples. • The SAX disk adsorbing dissolved Br was directly analyzed by WDXRF. • The accuracy of the SAX–WDXRF method was confirmed by spike and inter-comparison tests. • Rapid and sensitive Br analysis can be achieved using the proposed SAX–WDXRF method

  6. Preparation and electrocatalytic application of composites containing gold nanoparticles protected with rhodium-substituted polyoxometalates

    International Nuclear Information System (INIS)

    Substitution of a metal center of phosphomolybdate, PMo12O403- (PMo12), or its tungsten analogue with dirhodium(II) and subsequent stabilization of gold nanoparticles, AuNPs, with Rh2PMo11 are demonstrated. The AuNP-Rh2PMo11 mediates oxidations but adsorbs too weakly for direct modification of electrode materials. Stability in quiescent solution was achieved by modifying glassy carbon (GC) with 3-aminopropyltriethoxysilane (APTES) and then electrostatically assembling AuNP-Rh2PMo11. At GC|APTES|AuNP-Rh2PMo11, cyclic voltammetry showed the expected set of three reversible peak-pairs for PMo11 in the range -0.2 to 0.6 vs. (Ag/AgCl)/V and the reversible RhII,III couple at 1.0 vs. (Ag/AgCl)/V. The presence of AuNPs increased the current for the reduction of bromate by a factor of 2.5 relative to that at GC|Rh2PMo11, and the electrocatalytic oxidation of methionine displayed characteristics of synergism between the AuNP and RhII. To stabilize AuNP-Rh2PMo11 on a surface in a flow system, GC was modified by electrochemically assisted deposition of a sol-gel with templated 10-nm pores prior to immobilizing the catalyst in the pores. The resulting electrode permitted determination of bromate by flow-injection amperometry with a detection limit of 4.0 x 10-8 mol dm-3.

  7. UTILIZATION OF BROMINATION REACTION FOR THE SPECTROPHOTOMETRIC ASSAY OF DOMPERIDONE IN PHARMACEUTICALS

    Directory of Open Access Journals (Sweden)

    O. ZENITA DEVI

    2011-03-01

    Full Text Available Three simple and sensitive spectrophotometric methods are described for the determination of domperidone (DOM in bulk drug and in dosage forms using bromate-bromide mixture as brominating agent in acid medium and three dyes, meta-cresol purple (MCP, amaranth (AMR and erioglaucine (EGC. The methods involve the addition of a known excess of bromate-bromide mixture to an acidified solution of DOM followed by the determination of the residual bromine by reacting with a fixed amount of either MCP dye and measuring the absorbance at 530 nm (method A or AMR dye and measuring the absorbance at 520 nm (method B or EGC dye and measuring the absorbance at 630 nm (method C. Beer’s law is obeyed over the concentration ranges, 0.63–10.0, 0.25-4.0 and 0.13-2.0 µg mL-1 for method A, B and C, respectively. The ap¬parent molar absorptivities are calculated to be 3.751x104, 6.604x104 and 1.987x105 L mol-1cm-1 for method A, B and C, respectively, and the corresponding sandell sensitivity values are 0.011, 0.006 and 0.002 μg cm-2. The limit of detection and the limit of quantification are also reported for all the three methods. No interference was observed from common additives found in pharmaceutical preparations. Statistical comparisons of the results with those of the reference method showed excellent agreement, and indicated no significant difference in accuracy and precision. The accuracy and reliability of the methods were further ascertained by performing recovery tests via standardaddition technique.

  8. Organic Contaminant Abatement in Reclaimed Water by UV/H2O2 and a Combined Process Consisting of O3/H2O2 Followed by UV/H2O2: Prediction of Abatement Efficiency, Energy Consumption, and Byproduct Formation.

    Science.gov (United States)

    Lee, Yunho; Gerrity, Daniel; Lee, Minju; Gamage, Sujanie; Pisarenko, Aleksey; Trenholm, Rebecca A; Canonica, Silvio; Snyder, Shane A; von Gunten, Urs

    2016-04-01

    UV/H2O2 processes can be applied to improve the quality of effluents from municipal wastewater treatment plants by attenuating trace organic contaminants (micropollutants). This study presents a kinetic model based on UV photolysis parameters, including UV absorption rate and quantum yield, and hydroxyl radical (·OH) oxidation parameters, including second-order rate constants for ·OH reactions and steady-state ·OH concentrations, that can be used to predict micropollutant abatement in wastewater. The UV/H2O2 kinetic model successfully predicted the abatement efficiencies of 16 target micropollutants in bench-scale UV and UV/H2O2 experiments in 10 secondary wastewater effluents. The model was then used to calculate the electric energies required to achieve specific levels of micropollutant abatement in several advanced wastewater treatment scenarios using various combinations of ozone, UV, and H2O2. UV/H2O2 is more energy-intensive than ozonation for abatement of most micropollutants. Nevertheless, UV/H2O2 is not limited by the formation of N-nitrosodimethylamine (NDMA) and bromate whereas ozonation may produce significant concentrations of these oxidation byproducts, as observed in some of the tested wastewater effluents. The combined process of O3/H2O2 followed by UV/H2O2, which may be warranted in some potable reuse applications, can achieve superior micropollutant abatement with reduced energy consumption compared to UV/H2O2 and reduced oxidation byproduct formation (i.e., NDMA and/or bromate) compared to conventional ozonation. PMID:26909504

  9. Synthesis, characterization, magnetic and electrochemical properties of a new 3D hexa-copper-substituted germanotungstate

    International Nuclear Information System (INIS)

    An inorganic–organic hybrid hexa-copper-substituted germanotungstate Na2[Cu(dap)2]2[Cu(dap)2] ([Cu6(H2O)2(dap)2][B-α-GeW9O34]2)·4H2O (1) (dap=1,2-diaminopropane) has been hydrothermally prepared and characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP–AES) analyses, IR spectra, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and single-crystal X-ray diffraction. 1 displays the six-connected 3D network with the long topological (O′Keefe) vertex symbol is 4·4·64·4·4·4·4·64·4·4·4·64·4·4·4 and the short vertex (Schläfli) symbol of 41263. Magnetic measurements indicate that there are the overall ferromagnetic exchange interactions in the belt-like hexa-CuII cluster in 1. Furthermore, the electrochemical behavior and electrocatalysis of 1 modified carbon paste electrode (1-CPE) have been studied. The reductions of nitrite, bromate and hydrogen peroxide are principally mediated by the WVI-based wave. - Graphical abstract: A hexa-CuII sandwiched germanotungstate has been synthesized and structurally characterized. The magnetic, solid-state electrochemical and electrocatalytic properties have been investigated. Display Omitted - Highlights: • Transition-metal substituted polyoxometalates. • Hexa-copper-substituted germanotungstate. • Six-connected 3D network. • Electrocatalytic reduction of nitrite, bromate and hydrogen peroxide

  10. 饮用水中草甘膦的离子色谱法测定%Determination of Glyphosate in Drinking Water

    Institute of Scientific and Technical Information of China (English)

    吴燕琴; 郭梁钻; 谢丽章

    2012-01-01

    目的:建立一次进样同时测定饮用水中溴酸盐、草甘膦的离子色谱测定法。方法:选用DIONEX ICS-2000型离子色谱仪,用离子色谱法测定饮用水氟离子、溴酸盐、氯离子、溴离子、硝酸盐氮、硫酸盐、磷酸盐和草甘膦等离子,分离效果理想、灵敏度较高。进样量100μL。结果溴酸盐、溴离子、磷酸盐、草甘膦的检出限分别为:4.0μg/L、4.0μg/L、5.2μg/L、4.4μg/L;标准偏差〈5%;样品加标回收率在88.0%~104.0%之间。结论:该方法操作简单,分析快速,灵敏度高,重现性好,能够准确检测水中草甘膦含量。%Objective: A novel method covered the determination of the bromate and glyphosate in drinking water by chemically and electrolytically suppressed ion chromatography.Results: The detection limits for bromate,bromine ion,phosphate and glyphosate was 4.0 μg/L、4.0 μg/L、5.2 μg/L、4.4 μg/L.The RSD 5 %,and the recoveries of the method for them were between 88.0 %~104.0 %.Conclusion: The method established in the present paper was simple,precise,sensitive and suitable for determination of glyphosate.Its advantages were simple operation,speediness,high sensitivity,good repeatability.

  11. Analysis of Diurnal Variations in Energy Footprint and Its Associated Carbon Emission for Water Supply and Reuse in Arid and Semi-Arid Areas

    Science.gov (United States)

    Sobhani, Reza

    characterized by water scarcity, such as Southern California, groundwater containing chromophoric dissolved organic matter is a viable source of water supply. However, the seawater intrusion increased the concentration of bromide in extracted groundwater. Bromide, a precursor to bromate formation is regulated by USEPA as a potential carcinogen. This study compares the energy footprint among the two processes utilized for treatment of highly colored groundwater (i.e. nanofiltration and ozone injection coupled with biologically activated carbon) and discusses the impacts of bromate formation among these processes.

  12. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    Directory of Open Access Journals (Sweden)

    Hideki Wanibuchi

    2013-10-01

    Full Text Available This review highlights several in vivo studies utilizing non-genotoxic and genotoxic chemical carcinogens, and the mechanisms of their high and low dose carcinogenicities with respect to formation of oxidative stress. Here, we survey the examples and discuss possible mechanisms of hormetic effects with cytochrome P450 inducers, such as phenobarbital, a-benzene hexachloride and 1,1-bis(p-chlorophenyl-2,2,2-trichloroethane. Epigenetic processes differentially can be affected by agents that impinge on oxidative DNA damage, repair, apoptosis, cell proliferation, intracellular communication and cell signaling. Non-genotoxic carcinogens may target nuclear receptors and induce post-translational modifications at the protein level, thereby impacting on the stability or activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. We further discuss role of oxidative stress focusing on the low dose carcinogenicities of several genotoxic carcinogens such as a hepatocarcinogen contained in seared fish and meat, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, arsenic and its metabolites, and the kidney carcinogen potassium bromate.

  13. Photocatalytic degradation of a widely used insecticide Thiamethoxam in aqueous suspension of TiO2: Adsorption, kinetics, product analysis and toxicity assessment

    International Nuclear Information System (INIS)

    This paper deals with the study of photocatalyzed degradation of an insecticide, Thiamethoxam in aqueous suspension of TiO2. The adsorption of Thiamethoxam on TiO2 surface under dark conditions was also investigated in order to find out equilibrium adsorption constant. The degradation kinetics was studied using spectrophotometric method under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and in the presence of electron acceptors such as hydrogen peroxide, potassium bromate, and ammonium persulphate under continuous purging of atmospheric oxygen, and the degradation rates were found to be strongly influenced by these parameters. The results manifested that the photocatalysis of Thiamethoxam follows pseudo-first-order kinetics. The toxicity assessments of the irradiated samples were carried out using human erythrocytes as a model system under in vitro conditions. GC–MS study showed the formation of several intermediate products which were characterised based on their molecular mass and mass fragmentation pattern. A probable mechanism for the formation of various products formed during the photocatalytic process of Thiamethoxam was also proposed. Highlights: • TiO2 P25 is a more efficient photocatalyst than UV100 and PC500 for degradation of Thiamethoxam. • Low H2O2 dosages enhance degradation whereas overdose retards it. • Toxicity of Thiamethoxam decreases with the increase in irradiation time. • Eight intermediate products have been identified using GC–MS analysis technique

  14. Methyl chloride and methyl bromide emissions from baking: an unrecognized anthropogenic source.

    Science.gov (United States)

    Thornton, Brett F; Horst, Axel; Carrizo, Daniel; Holmstrand, Henry

    2016-05-01

    Methyl chloride and methyl bromide (CH3Cl and CH3Br) are the largest natural sources of chlorine and bromine, respectively, to the stratosphere, where they contribute to ozone depletion. We report the anthropogenic production of CH3Cl and CH3Br during breadbaking, and suggest this production is an abiotic process involving the methyl ester functional groups in pectin and lignin structural polymers of plant cells. Wide variations in baking styles allow only rough estimates of this flux of methyl halides on a global basis. A simple model suggests that CH3Br emissions from breadbaking likely peaked circa 1990 at approximately 200tonnes per year (about 0.3% of industrial production), prior to restrictions on the dough conditioner potassium bromate. In contrast, CH3Cl emissions from breadbaking may be of similar magnitude as acknowledged present-day CH3Cl industrial emissions. Because the mechanisms involve functional groups and compounds widely found in plant materials, this type of methyl halide production may occur in other cooking techniques as well. PMID:26878644

  15. Chromatographic isolation of 144Ce and 144Pr from the wastes of irradiated uranium treatment

    International Nuclear Information System (INIS)

    A two-step chromatographic technique was elaborated to isolate 144Ce, 144Pr from a solution of uranium fission products in 6M HNO3. The oxidation to Ce(III) by bromate and selective adsorption of 144Ce(IV) on anion exchange column were used to concentrate and purify 144Ce. Some impurities of uranium, 95Zr, 95Nb, 106Ru remain in 144Ce solution after the first step of its isolation. The final purification is achieved by passing the 6M HNO3 solution of 144Ce(IV) through the HDEHP-coated teflon column. The decontamination factors of 144Ce from main fission products are given. 7.2 mCi of (144Ce+144Pr) are recovered from each gram of irradiated uranium trioxide with the yield greater than 99%. An improvement of known generator was carried out to elute a purer 144Pr from maternal 144Ce(IV) adsorbed on the anion exchange column. (author)

  16. Flow injection kinetic spectrofluorimetric determination of trace amounts of osmium

    Science.gov (United States)

    Tang, Bo; Zhang, Hui; Wang, Yan

    2005-07-01

    A flow injection (FI) kinetic spectrofluorimetric method is described for the determination of osmium(IV) and the possible mechanism of catalytic reaction is discussed. The method is based on the fluorescence enhancing reaction of o-vanillin furfuralhydrazone (OVFH) with potassium bromate, which is catalyzed by Os(IV) in water medium at pH 6.10 and 45 °C. OVFH is newly synthesized and its ionization, IR and elemental analysis are established. Under these experimental conditions, the oxidized product of OVFH has excitation and emission maxima at 337 and 490 nm, respectively. The linear range of this method is 0-600 ng ml -1 with the R.S.D. of 1.2%. The detection limit is 1.0 ng ml -1 of Os(IV). A high analysis rate of 24 samples h -1 is obtained by the FI method. The proposed method is applied successfully to determine Os(IV) in synthetic mixture and mineral samples, and the results are well consistent with the standard values.

  17. [Removal characters of ozone-biological activated carbon process for typical pollutants in southern brooky regions of China].

    Science.gov (United States)

    Lin, Tao; Chen, Wei; Wang, Lei-Lei

    2009-05-15

    The products of relative molecular weight (Mr) distribution, bromate (BrO3(-)) and trihalomethanes (THMs) were studied by ozone-biological activated carbon (O3-BAC) process for treating organic matters and bromide (Br(-)) in water source of southern brooky regions of China. The experimental results showed that dissolved organic matters (DOC) with Mr lower than 10(3) accounted for 80% of the total. The removal rate of DOC and SUVA (UV254/DOC) were 8% and 14% respectively by traditional treatment process with main removalonly for ones with Mr higher than 100 x 10(3). Only 30% of DOC and 31% of SUVA were decreased by O3-BAC process for the removal of ones with Mr between 10(3) and 5 x 10(3), in which the biotic degradation was certainly restricted by predominant organic matters of hydrophilic and Mr was lower than 1000. An obvious increase of BrO3(-) occurred in the effluent from ozone oxidation process when the dose of ozone beyond 2 mg/L which increased Br(-) concentration. This could increase the product of BrO3(-). A poor and unstable removal effect of BrO3(-) was observed in the effluent of BAC process during the experiment. Each species of THMs, decreasing 40% of total, was reduced by O3-BAC treatment compared with the traditional treatment process. But the products of brominated trihalomethanes, especially CHBr3 would be markedly increased by enhanced chlorine dosage and Br(-) concentration. PMID:19558108

  18. Integration of vanadium-mixed addenda Dawson heteropolytungstate within poly(3,4-ethylenedioxythiophene) and poly(2,2'-bithiophene) films by electrodeposition from the nonionic micellar aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Goral, Monika [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Jouini, Mohamed, E-mail: jouini@univ-paris-diderot.f [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Perruchot, Christian [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Miecznikowski, Krzysztof; Rutkowska, Iwona A. [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Kulesza, Pawel J., E-mail: pkulesza@chem.uw.edu.p [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

    2011-04-01

    A comparative study describing immobilization of the Dawson type mixed addenda heteropolyanion, [P{sub 2}W{sub 17}VO{sub 62}]{sup 8-} into conducting polymer films of poly(3,4-ethylenedioxythiophene), PEDOT, and poly(2,2'-bithiophene), PBT, is reported. Electrosynthesis of these hybrid films was performed using a micellar aqueous solution of the nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-100). Deposited composite films were characterised electrochemically and, on the whole, they exhibited fast electron transfer (ET) properties and relatively high stability towards continuous potential cycling in acidic media. In particular, PEDOT composite showed relatively faster ET properties in comparison to PBT composite. Their permeability was investigated in the presence of cationic and anionic redox probes. Our results implied good mediating capabilities of the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-} anion (within the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-}-PEDOT hybrid film) towards the iron (III) reduction. The specific electrocatalytic (reductive) capabilities of hybrid films were also studied by probing the reduction of bromate. The films were further characterised by X-ray photoelectron spectroscopy to establish their interfacial elemental composition. Moreover, their surface morphology was imaged by atomic force microscopy and scanning electron microscopy. Results have shown that physicochemical properties of the investigated hybrid films were affected by polymer hydrophobicity.

  19. Integration of vanadium-mixed addenda Dawson heteropolytungstate within poly(3,4-ethylenedioxythiophene) and poly(2,2'-bithiophene) films by electrodeposition from the nonionic micellar aqueous medium

    International Nuclear Information System (INIS)

    A comparative study describing immobilization of the Dawson type mixed addenda heteropolyanion, [P2W17VO62]8- into conducting polymer films of poly(3,4-ethylenedioxythiophene), PEDOT, and poly(2,2'-bithiophene), PBT, is reported. Electrosynthesis of these hybrid films was performed using a micellar aqueous solution of the nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-100). Deposited composite films were characterised electrochemically and, on the whole, they exhibited fast electron transfer (ET) properties and relatively high stability towards continuous potential cycling in acidic media. In particular, PEDOT composite showed relatively faster ET properties in comparison to PBT composite. Their permeability was investigated in the presence of cationic and anionic redox probes. Our results implied good mediating capabilities of the [P2W17V4+O62]8- anion (within the [P2W17V4+O62]8--PEDOT hybrid film) towards the iron (III) reduction. The specific electrocatalytic (reductive) capabilities of hybrid films were also studied by probing the reduction of bromate. The films were further characterised by X-ray photoelectron spectroscopy to establish their interfacial elemental composition. Moreover, their surface morphology was imaged by atomic force microscopy and scanning electron microscopy. Results have shown that physicochemical properties of the investigated hybrid films were affected by polymer hydrophobicity.

  20. Extraction of tetravalent berkelium and cerium by aliquate-336-S-NO3 quaternary ammonium salt

    International Nuclear Information System (INIS)

    Extraction of tetravalent berkelium and cerium by aliquate-336-S-NO3 quaternary ammonium salt from nitric acid solutions is investigated. The effect of concentrations of nitric acid and extracting agent, nature of an oxidant (potassium bromate, potassium bichromate, mixture of AgNO3 and (NH4)2S2O8) and solvent on the distribution coefficient of berkelium(4) and cerium(4) is studied. It is established that solutions of aliquate-336-S-NO3 in carbon tetrachloride and dichloroethane extract quantitatively tetravalent berkelium from 10-12 M nitric acid solutions and cerium - from 1-10 M nitric acid solutions containing potassium bichromate as an oxidant. It is shown that the value of distribution coefficient for berkelium and cerium depends on the nature of an oxidant and extracting agent concentration. It is established that in the case of extraction by quaternary ammonium salt with one berkelium(4) mole four aliquate-336-SNO3 moles are associated and 1.5-1.6 mole of extracting agent are associated with one cerium(4) mole. It permits to make a conclusion that stoichiometry of extraction reactions by quaternary ammonium salt is not the same for tetravalent berkelium and cerium. It is shown that trivalent transplutonium and rare earth elements are not practically extracted by aliquate-336-S-NO3 from nitric acid solutions

  1. Controlling various contaminants in wastewater effluent through membranes and engineered wetland

    Institute of Scientific and Technical Information of China (English)

    Sarper SARP; Sungyun LEE; Noeon PARK; Nguyen Thi HANH; Jaeweon CHO

    2009-01-01

    For effective wastewater reclamation and water recovery, the treatment of natural and effluent organic matters (NOM and EfOM), toxic anions, and micropollutants was considered in this work. Two different NOM (humic acid of the Suwannee River, and NOM of US and Youngsan River, Korea), and one EfOM from the Damyang wastewater treatment plant, Korea, were selected for investigating the removal efficiencies of tight nanofiltration (NF) and ultrafiltration (UF) membranes with different properties. Nitrate, bromate, and perchlorate were selected as target toxic anions due to their well known high toxicities. Tri-(2-chloroethyl)-phosphate (TCEP),oxybenzone, and caffeine, due to their different Kow and pKa values, were selected as target micropollutants. As expected, the NF membranes provided high removal efficiencies in terms of all the tested contaminants, and the UF membrane provided fairly high removal efficien-cies for anions (except for nitrate) and the relatively hydrophobic micropollutant, oxybenzon. Through the wetlands, nitrate was successfully removed. Therefore, a fair process of combining membranes with an engineered wetland could be proposed for sustainable wastewater reclamation and optimum control of contaminats.

  2. An on-line spectrophotometric determination of trace amounts of thiourea in tap water, orange juice, and orange peel samples using multi-channel flow injection analysis.

    Science.gov (United States)

    Arab Chamjangali, M; Goudarzi, N; Ghochani Moghadam, A; Amin, A H

    2015-10-01

    In this work, a flow injection analysis (FIA) method was introduced for the determination of trace amounts of thiourea in tap water. This method is based upon the inhibition effect of thiourea on the reaction between meta-cresol purple (MCP) and potassium bromate catalyzed by bromide ions in a sulfuric acid medium. In the presence of thiourea, an induction period appears in the reaction system, and as a result, the absorbance of MCP increases at 525 nm in the FIA manifold. The chemical and FIA variables are studied and optimized using the univariate and Simplex optimization methods. Under the optimum conditions, thiourea can be determined in the range of 0.100-13.0 μg mL(-1). The limit of detection (3σ) for thiourea was found to be 0.0310 μg mL(-1). The relative standard deviations (RSDs) for six replicate determinations of 0.500, 5.00, and 12.0 μg mL(-1) of thiourea were 4.0%, 1.8%, and 1.2%, respectively. The proposed method was also applied for the determination of thiourea in orange juice and orange peel samples with recoveries in the range of 98.0-101%. The analytical speed of the method was calculated to be about 120 sample per hour. PMID:25985122

  3. EFFECTS STUDY OF NIGELLA SATIVA, ITS OIL AND THEIR COMBINATION WITH VITAMIN E ON OXIDATIVE STRESS IN RATS

    Directory of Open Access Journals (Sweden)

    Amr A. Rezq

    2014-01-01

    Full Text Available Antioxidants or free radical scavengers are very important in protecting the living cells against any damage induced by free radicals. The effects of Nigella Sativa Extract (NSE, Nigella Sativa Oil (NSO and Vitamin E (Vit. E and the combination of NSE or NSO with Vit. E on potassium bromate (KBrO3-induced oxidative stress in male rats were investigated. Forty nine Sprague Dawley male rats were weighingv 185±5 g and 10-12 weeks old were used to achieve the present study. According to the results, oral administration of NSE or NSO alone and in combination with vitamin E exhibited weight gain and feed efficiency ratio and lowered the elevated serum levels of total cholesterol, triglycerides, AST, ALT, urea nitrogen, uric acid and creatinine. Further, they lowered malondialdehyde and increased the reduction in glutathione content and activities of antioxidant enzymes (GPx, SOD and CAT in liver tissues. Collectively, these results indicate that dietary intake of NSE or NSO alone and in combination with Vitamin E could be a potential therapeutic in the treatment of related diseases with oxidative stress."

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

  5. New inorganic (an)ion exchangers based on Mg–Al hydrous oxides: (Alkoxide-free) sol–gel synthesis and characterisation

    KAUST Repository

    Chubar, Natalia

    2011-05-01

    New inorganic ion exchangers based on double Mg-Al hydrous oxides were generated via the new non-traditional sol-gel synthesis method which avoids using metal alkoxides as raw materials. Surface chemical and adsorptive properties of the final products were controlled by several ways of hydrogels and xerogels treatments which produced the materials of the layered structure, mixed hydrous oxides or amorphous adsorbents. The final adsorptive materials obtained via thermal treatment of xerogels were the layered mesoporous materials with carbonate in the interlayer space, surface abundance with hydroxylic groups and maximum adsorptive capacity to arsenate. Higher affinity of Mg-Al hydrous oxides towards H2AsO4- is confirmed by steep adsorption isotherms having plateau (removal capacity) at 220. mg[As]. gdw-1 for the best sample at pH = 7, fast adsorption kinetics and little pH effect. Adsorption of arsenite, fluoride, bromate, bromide, selenate, borate by Mg-Al hydrous oxides was few times high either competitive (depending on the anion) as compare with the conventional inorganic ion exchange adsorbents. © 2011 Elsevier Inc.

  6. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    Energy Technology Data Exchange (ETDEWEB)

    Kakehashi, Anna; Wei, Min [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585 (Japan); Fukushima, Shoji [Japan Bioassay Research Center, Japan Industrial Safety and Health Association, 2445 Hirasawa, Hadano, Kanagawa 257-0015 (Japan); Wanibuchi, Hideki, E-mail: wani@med.osaka-cu.ac.jp [Department of Pathology, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-Ku, Osaka 545-8585 (Japan)

    2013-10-28

    This review highlights several in vivo studies utilizing non-genotoxic and genotoxic chemical carcinogens, and the mechanisms of their high and low dose carcinogenicities with respect to formation of oxidative stress. Here, we survey the examples and discuss possible mechanisms of hormetic effects with cytochrome P{sub 450} inducers, such as phenobarbital, α-benzene hexachloride and 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane. Epigenetic processes differentially can be affected by agents that impinge on oxidative DNA damage, repair, apoptosis, cell proliferation, intracellular communication and cell signaling. Non-genotoxic carcinogens may target nuclear receptors and induce post-translational modifications at the protein level, thereby impacting on the stability or activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. We further discuss role of oxidative stress focusing on the low dose carcinogenicities of several genotoxic carcinogens such as a hepatocarcinogen contained in seared fish and meat, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, arsenic and its metabolites, and the kidney carcinogen potassium bromate.

  7. Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs)

    International Nuclear Information System (INIS)

    Managing the provision of safe drinking water has a renewed focus in light of the new World Health Organization (WHO) water safety plans. Risk analysis is a necessary component to assist in selecting priority hazards and identifying hazardous scenarios, be they qualitative to quantitative assessments. For any approach, acute diarrhoeal pathogens are often the higher risk issue for municipal water supplies, no matter how health burden is assessed. Furthermore, potential sequellae (myocarditis, diabetes, reactive arthritis and cancers) only further increase the potential health burden of pathogens; despite the enormous uncertainties in determining pathogen exposures and chemical dose-responses within respective microbial and chemical analyses. These interpretations are currently being improved by Bayesian and bootstrapping approaches to estimate parameters for stochastic assessments. A case example, covering the health benefits of ozonation for Cryptosporidium inactivation versus potential cancers from bromate exposures, illustrated the higher risks from a pathogen than one of the most likely disinfection by-products (DBPs). Such analyses help justify the industries long-held view of the benefits of multiple barriers to hazards and that microbial contamination of water supplies pose a clear public health risk when treatment is inadequate. Therefore, efforts to reduce potential health risks from DBP must not compromise pathogen control, despite socio-political issues

  8. Evaluation of rheological, bioactives and baking characteristics of mango ginger (curcuma amada) enriched soup sticks.

    Science.gov (United States)

    Crassina, K; Sudha, M L

    2015-09-01

    Wheat flour was replaced with mango ginger powder (MGP) at 0, 5, 10 and 15 %. Influence of MGP on rheological and baking characteristics was studied. Farinograph was used to study the mixing profile of wheat flour-MGP blend. Pasting profile of the blends namely gelatinization and retrogradation were carried out using micro-visco-amylograph. Test baking was done to obtain the optimum level of replacement and processing conditions. Sensory attributes consisting texture, taste, overall quality and breaking strength were assessed. Nutritional characterization of the soup sticks in terms of protein and starch in vitro digestibility, dietary fiber, minerals, polyphenols and antioxidant activity were determined using standard methods. With the increasing levels of MGP from 0 to 15 %, the farinograph water absorption increased from 60 to 66.7 %. A marginal increase in the gelatinization temperature from 65.4 to 66.2 °C was observed. Retrogradation of gelatinized starch granules decreased with the addition of MGP. The results indicated that the soup stick with 10 % MG had acceptable sensory attributes. The soup stick showed further improvement in terms of texture and breaking strength with the addition of gluten powder, potassium bromate and glycerol monostearate. The total dietary fiber and antioxidant activity of the soup sticks having 10 % MGP increased from 3.31 to 8.64 % and 26.83 to 48.06 % respectively as compared to the control soup sticks. MGP in soup sticks improved the nutritional profile. PMID:26345009

  9. Determination of acrylamide in starch-based foods by HPLC with pre-column ultraviolet derivatization.

    Science.gov (United States)

    Geng, Zhiming; Wang, Peng; Liu, Aiming

    2011-01-01

    A new method is developed for the determination of acrylamide in starch-based foods. The method included the extraction of acrylamide with water, defatting with hexane, derivatization with potassium bromate (KBrO(3)) and potassium bromide (KBr), liquid-liquid extraction with ethyl acetate-hexane (4:1), and concentration. The final analyte (2-bromopropenamide, 2-BPA) is analyzed by high-performance liquid chromatography coupled with diode array detection for quantification and by gas chromatography coupled to mass spectrometry for confirmation. The chromatographic analysis is performed on an ODS-3 C(18) column, and good retention and peak response of acrylamide are achieved under the optimal conditions. The limit of detection and quantitation are estimated to be 15 and 50 μg/kg, respectively. The recoveries of acrylamide from the commercial samples are spiked at levels of 50-1000 μg/kg, and range between 89.6 and 102.0%. These results show that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide. PMID:22080811

  10. Rapid determination of acrylamide contaminant in conventional fried foods by gas chromatography with electron capture detector.

    Science.gov (United States)

    Zhang, Yu; Dong, Yi; Ren, Yiping; Zhang, Ying

    2006-05-26

    Gas chromatography coupled with electron capture detector (GC-ECD) was successfully developed and applied for the rapid determination of acrylamide in conventional fried foods, such as potato crisps, potato chips, and fried chicken wings. The method included defatting with n-hexane, extraction with aqueous solution of sodium chloride (NaCl), derivatization with potassium bromate (KBrO3) and potassium bromide (KBr), and liquid-liquid extraction with ethyl acetate. The final acrylamide extract was analyzed by GC-ECD for quantification and by GC-MS for confirmation. The chromatographic analysis was performed on the HP-INNOWax capillary column, and good retention and peak response of acrylamide were achieved under the optimal conditions (numbers of theoretical plates N = 83,815). The limit of detection (LOD) was estimated to be 0.1 microg kg(-1) on the basis of ECD technique. Recoveries of acrylamide from conventional samples spiked at levels of 150, 500 and 1000 microg kg(-1) (n = 4 for each level) ranged between 87 and 97% with relative standard deviations (RSD) of less than 4%. Furthermore, the GC-ECD method showed that no clean-up steps of acrylamide derivative would be performed prior to injection and was slightly more sensitive than the MS/MS-based methods. Validation and quantification results demonstrated that this method should be regarded as a new, low-cost, and robust alternative for conventional investigation of acrylamide. PMID:16580677

  11. Bayesian analysis of physiologically based toxicokinetic and toxicodynamic models.

    Science.gov (United States)

    Hack, C Eric

    2006-04-17

    Physiologically based toxicokinetic (PBTK) and toxicodynamic (TD) models of bromate in animals and humans would improve our ability to accurately estimate the toxic doses in humans based on available animal studies. These mathematical models are often highly parameterized and must be calibrated in order for the model predictions of internal dose to adequately fit the experimentally measured doses. Highly parameterized models are difficult to calibrate and it is difficult to obtain accurate estimates of uncertainty or variability in model parameters with commonly used frequentist calibration methods, such as maximum likelihood estimation (MLE) or least squared error approaches. The Bayesian approach called Markov chain Monte Carlo (MCMC) analysis can be used to successfully calibrate these complex models. Prior knowledge about the biological system and associated model parameters is easily incorporated in this approach in the form of prior parameter distributions, and the distributions are refined or updated using experimental data to generate posterior distributions of parameter estimates. The goal of this paper is to give the non-mathematician a brief description of the Bayesian approach and Markov chain Monte Carlo analysis, how this technique is used in risk assessment, and the issues associated with this approach. PMID:16466842

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

    International Nuclear Information System (INIS)

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

  13. Solar photocatalytic H{sub 2} production from water using a dual bed photosystem

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A. [Florida Solar Energy Center, Cocoa, FL (United States)

    1996-10-01

    The authors are developing a dual stage, direct photoconversion scheme for water splitting. The overall system consists of an aqueous solution circulated through two modules, or beds, each of which contains a photochemically active surface layer below the solution. The idea is to divide the energy requirement for water decomposition between the two photosystems, so that more abundant, lower energy photons in the solar spectrum can be utilized, and that the H{sub 2} and O{sub 2} products can be evolved separately from each other. Catalyst-modified semiconductor powders, immobilized within a polymer binder are currently being employed as the photoactive layers. TiO{sub 2} and platinized-InP have been employed for the O{sub 2} and H{sub 2} evolution tasks, respectively. A major effort over the last year was identification of a suitable redox mediator that is responsible for transferring electron equivalents from one unit to the other. After testing more than a dozen candidates, spanning a wide range of electropotentials, under a variety of conditions, it was found that the bromide/bromate (Br{sup {minus}}/BrO{sub 3}{sup {minus}}) and iodide/iodate (I{sup {minus}}/IO{sub 3}{sup {minus}}) redox systems could function in both modules, necessary for closed cycle operation.

  14. PIXE analysis of Nigerian flour and bread samples

    Energy Technology Data Exchange (ETDEWEB)

    Olise, Felix S., E-mail: felix_olise@rushpost.com [Department of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Fernandes, Adriana M.; Cristina Chaves, P. [CFA: Centro de Física Atómica da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Taborda, Ana; Reis, Miguel A. [IST/CTN: Instituto Superior Técnico, Universidade Técnica de Lisboa, Campus Tecnológico e Nuclear (CTN), EN10, 2686-953 Sacavém (Portugal); CFA: Centro de Física Atómica da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal)

    2014-01-01

    Highlights: • The PIXE technique has been used to determine K and Br in a major Nigerian food item. • Samples were analysed using two proton beam energies, namely 1.25 MeV and 2.15 MeV. • Mismatched Ca results reflect its nature and accuracy/precision of the procedure. • Explanations for the presence of the contaminant in the samples are presented. • Other sources originating from erroneous burning of dangerous products suspected. -- Abstract: The alleged use of potassium bromate (KBrO{sub 3}) in bread baking led a few authors to report on the chemical methods for the determination of KBrO{sub 3} levels in bread. In order to examine the potentials of a non chemical particle induced X-ray emission (PIXE) method for this purpose, six sets of samples, each composed of flour, dough and bread from a production batch were analysed. The samples were obtained from six different bakers of bread at Ile-Ife, Nigeria. The flour samples were air-dried while others were freeze dried at about −16 °C. The samples were homogenised in an agate mortar and then pelletised. Samples were analysed at the CTN standard PIXE setup and standard procedures for thick target samples analysis were followed. In some samples significant concentrations of bromine were found. In the present work we present possible explanations for the presence of this potentially dangerous contaminant in the samples.

  15. PIXE analysis of Nigerian flour and bread samples

    International Nuclear Information System (INIS)

    Highlights: • The PIXE technique has been used to determine K and Br in a major Nigerian food item. • Samples were analysed using two proton beam energies, namely 1.25 MeV and 2.15 MeV. • Mismatched Ca results reflect its nature and accuracy/precision of the procedure. • Explanations for the presence of the contaminant in the samples are presented. • Other sources originating from erroneous burning of dangerous products suspected. -- Abstract: The alleged use of potassium bromate (KBrO3) in bread baking led a few authors to report on the chemical methods for the determination of KBrO3 levels in bread. In order to examine the potentials of a non chemical particle induced X-ray emission (PIXE) method for this purpose, six sets of samples, each composed of flour, dough and bread from a production batch were analysed. The samples were obtained from six different bakers of bread at Ile-Ife, Nigeria. The flour samples were air-dried while others were freeze dried at about −16 °C. The samples were homogenised in an agate mortar and then pelletised. Samples were analysed at the CTN standard PIXE setup and standard procedures for thick target samples analysis were followed. In some samples significant concentrations of bromine were found. In the present work we present possible explanations for the presence of this potentially dangerous contaminant in the samples

  16. Heterogeneous photocatalysed degradation of two selected pesticide derivatives, triclopyr and daminozid in aqueous suspensions of titanium dioxide.

    Science.gov (United States)

    Qamar, M; Muneer, M; Bahnemann, D

    2006-07-01

    Heterogeneous photocatalysed degradation of two selected pesticide derivatives, triclopyr (1) and daminozid (2), has been investigated in aqueous suspensions of titanium dioxide by monitoring the change in substrate concentration employing the UV Spectroscopic analysis technique and depletion of Total Organic Carbon (TOC) content as a function of irradiation time. The degradation kinetics were studied under different conditions such as reaction pH, substrate and catalyst concentration, different types of TiO2 and in the presence of electron acceptors such as hydrogen peroxide (H2O2), potassium bromate (KBrO3) and ammonium persulphate (NH4)2S2O8 in addition to molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with other photocatalysts. The pesticide derivative triclopyr (1) was found to degrade faster as compared to daminozid (2). An attempt was also made to identify the intermediate products formed during the photooxidation process using GC/MS analysis. Probable pathways for the formation of products have been proposed. PMID:16359776

  17. The use of ion chromatography in environmental and process control in the nuclear industry. Vol. 4

    International Nuclear Information System (INIS)

    Ion chromatography has become the method choice for determining sub ppb for inorganic anions and cations, such as chloride, sulfide, fluoride, sodium, potassium, and ammonium, in aqueous matrices. Steam generators in pressurized water reactors nuclear power plants occasionally experience tubing degradation by a variety of corrosion related mechanisms which depends on water chemistry. Ion chromatography is also used in other environmental applications such as air pollution, industrial hygiene, drinking water quality, and industrial waste treatment. In this paper, several methods of separation and detection are present and also a number of examples of samples for various types of water are shown. The examples will include sub ppb amounts of chloride, sulfate, sodium, potassium, and ammonium in high purity turbine steam. Testing of chlorinated drinking water for inorganic anions including chlorite, chloride chlorate nitrite, nitrate as other organic anions using chemically suppressed conductivity. The role of chemical suppression is discussed. The analysis of ppb levels of transition moles in high purity water using ion chromatography with post column derivatization and UV detection are reviewed. Testing of disinfected drinking water with ozone for bromate, the detection of cyanide in waste after acid digestion, and the detection of highly toxic hexavalent in the presence of trivalent chromium is discussed. A fast method for the analysis of rain water for anions and cations is described. The presentation will also show new method (chelation ion chromatography) which enables ppb levels of heavy metals to be determined as pollutants in difficult environmental matrices such seawater, and oyster tissue. 4 figs

  18. Nonequilibrium / nonlinear chemical oscillation in the virtual absence of gravity

    Science.gov (United States)

    Fujieda, S.; Mogami, Y.; Moriyasu, K.; Mori, Y.

    1999-01-01

    The Belousov-Zhabotinsky (BZ) reactions were used as typical examples of a nonlinear system far from equilibrium in connection with biological evolution. The virtual absence of gravity in the present work was given from the free-fall facility of Japan Microgravity Center (JAMIC) in Hokkaido. The reaction solution of BZ reaction was composed of bromate in sulfuric acid, 1,4-cyclohexanedione and ferroin to visualize the time development of patterns of chemical oscillations in the reaction-diffusion system. It is a bubble-free constitution in the aging of the reaction. Therefore, the setup constructed to collect image data via CCD cameras was simplified. The operation sequences of necessary devices were comprised of simple solid state relays which were started by a command from the operation room of JAMIC. The propagation profile of chemical patterns under microgravity of 10-5 g was collected as image data for 9.8 s, and processed by a software of STM-STS2. In the aqueous solutions, propagation velocity of chemical patterns under microgravity was decreased to 80.9 % of that under normal gravity, owing to suppression of convection. On the other hand, in gel matrix, gravity did not influence the propagation velocity.

  19. Photocatalytic degradation of a widely used insecticide Thiamethoxam in aqueous suspension of TiO{sub 2}: Adsorption, kinetics, product analysis and toxicity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Mir, Niyaz A.; Khan, A. [Department of Chemistry, Aligarh Muslim University, Aligarh-202002, UP (India); Muneer, M., E-mail: readermuneer@gmail.com [Department of Chemistry, Aligarh Muslim University, Aligarh-202002, UP (India); Vijayalakhsmi, S. [SAIF, CRNTS, IIT Bombay, Powai, 400076, Mumbai (India)

    2013-08-01

    This paper deals with the study of photocatalyzed degradation of an insecticide, Thiamethoxam in aqueous suspension of TiO{sub 2}. The adsorption of Thiamethoxam on TiO{sub 2} surface under dark conditions was also investigated in order to find out equilibrium adsorption constant. The degradation kinetics was studied using spectrophotometric method under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and in the presence of electron acceptors such as hydrogen peroxide, potassium bromate, and ammonium persulphate under continuous purging of atmospheric oxygen, and the degradation rates were found to be strongly influenced by these parameters. The results manifested that the photocatalysis of Thiamethoxam follows pseudo-first-order kinetics. The toxicity assessments of the irradiated samples were carried out using human erythrocytes as a model system under in vitro conditions. GC–MS study showed the formation of several intermediate products which were characterised based on their molecular mass and mass fragmentation pattern. A probable mechanism for the formation of various products formed during the photocatalytic process of Thiamethoxam was also proposed. Highlights: • TiO{sub 2} P25 is a more efficient photocatalyst than UV100 and PC500 for degradation of Thiamethoxam. • Low H{sub 2}O{sub 2} dosages enhance degradation whereas overdose retards it. • Toxicity of Thiamethoxam decreases with the increase in irradiation time. • Eight intermediate products have been identified using GC–MS analysis technique.

  20. FIA versatile system for spectrophotometric determinations of vanadium and molybdenum exploring the catalytic activities of V(V) and Mo(VI)

    International Nuclear Information System (INIS)

    A versatile system for chemical analysis by flow injection analysis was developed and applied for catalytic spectrophotometric determination of vanadium or molybdenum in metallic alloys. The selected methods were based upon indicator reactions chromotropic (CS)-bromate acid or hydrogen iodide-peroxide, respectively. Initially, a model system was proposed, in which common parameters for methods were studied. This included a re-sampling process in which high degrees of samples dilution were obtained. Other parameters such as concentrations and reagents addition order, reaction medium Ph, temperature and ionic power, as well as procedures for sample solubilization, were studied relating to each method. A mini-column with cationic exchanger resin (Dowex 50W-X8, 50-100 mesh, H+ form) was used. The system for vanadium determination processes 120 samples by hour, consuming 2,0 mg CS and 10 mg K Br O3by determination. Concerning the method for molybdenum, the reagents consumption was 2,0 mg KI and 1,0 μL of solution 30% H2O2 by determination, since the analytic velocity was the same, in relation to vanadium

  1. 流动注射动力学光度法测定环境雌激素双酚A%Flow injection spectrophotometric determination of environmental estrogen bisphenol A

    Institute of Scientific and Technical Information of China (English)

    王广军; 高霞; 樊静; 刘国光

    2011-01-01

    A flow injection spectrophotometric method is developed for the measurement of environmental estrogen bisphenol A. The method is based on the inhibitory effect of bisphenol A on the oxidation reaction of gallocyanin by potassium bromate in hydrochloric acid medium. The detection limit for bisphenol A is 0. 027 μg/mL, and the linear range of the determination for bisphenol A is 0. 10 ~ 1.1 μg/mL. This method has been applied successfully to the determination of bisphenol A in nasal aspirator, feeding bottle, beverage bottle,false teeth, topsoil and surface water.%在HCl介质中,增敏剂十六烷基三甲基溴化铵存在下双酚A对KBrO3氧化棓花青褪色反应有明显的抑制作用,据此建立了测定痕量双酚A的流动注射动力学光度分析法.方法的线性范围为0.10~1.10μg/mL,检出限0.027μg/mL,回收率在96%~103%之间.该方法已用于吸鼻器、奶瓶、饮料瓶、假牙、表层土和地表水中双酚A含量的测定.

  2. Laser-induced removal of a dye C.I. Acid Red 87 using n-type WO{sub 3} semiconductor catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, M. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Hayat, K. [Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Yamani, Z.H. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Laser Research Laboratory, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Hooshani, K. [Center of Excellence in Nanotechnology, King Fahd University of Petroleum and Minerals, KFUPM Box 741, Dhahran 31261 (Saudi Arabia); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2009-10-30

    Water contamination by organic substances such as dyes is of great concern worldwide due to their utilization in many industrial processes and environmental concerns. To cater the needs for waste water treatment polluted with organic dyes, laser-induced photocatalytic process was investigated for removal of a dye derivative namely Acid Red 87 using n-type WO{sub 3} semiconductor catalyst. The degradation was investigated in aqueous suspensions of tungsten oxide under different experimental conditions using laser instead of conventional UV lamp as an irradiation source. The degradation process was monitored by measuring the change in dye concentration as a function of laser irradiation time by employing UV spectroscopic analysis. The degradation of dye was studied by varying different parameters such as laser energy, reaction pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H{sub 2}O{sub 2}), and potassium bromate (KBrO{sub 3}). The degradation rates were found to be strongly dependent on all the above-mentioned parameters. Our experimental results revealed that the dye degradation process was very fast (within few minutes) under laser irradiation as compared to conventional setups using broad spectral lamps (hours or days) and this laser-induced photocatalytic degradation method could be an effective means to eliminate the pollutants present in liquid phase. The experience gained through this study could be beneficial for treatment of waste water contaminated with organic dyes and other organic pollutants.

  3. FIA versatile system for spectrophotometric determinations of vanadium and molybdenum exploring the catalytic activities of V(V) and Mo(VI); Sistema FIA polivalente para determinacoes espectrofotometricas de vanadio e molibdenio explorando as atividades cataliticas de V(V) e Mo(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Gilmara Caseri de

    1996-02-01

    A versatile system for chemical analysis by flow injection analysis was developed and applied for catalytic spectrophotometric determination of vanadium or molybdenum in metallic alloys. The selected methods were based upon indicator reactions chromotropic (CS)-bromate acid or hydrogen iodide-peroxide, respectively. Initially, a model system was proposed, in which common parameters for methods were studied. This included a re-sampling process in which high degrees of samples dilution were obtained. Other parameters such as concentrations and reagents addition order, reaction medium Ph, temperature and ionic power, as well as procedures for sample solubilization, were studied relating to each method. A mini-column with cationic exchanger resin (Dowex 50W-X8, 50-100 mesh, H{sup +} form) was used. The system for vanadium determination processes 120 samples by hour, consuming 2,0 mg CS and 10 mg K Br O{sub 3b}y determination. Concerning the method for molybdenum, the reagents consumption was 2,0 mg KI and 1,0 {mu}L of solution 30% H{sub 2}O{sub 2} by determination, since the analytic velocity was the same, in relation to vanadium.

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

    International Nuclear Information System (INIS)

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

  5. Evaluation of the sensitivity of three sublethal cytotoxicity assays in human HepG2 cell line using water contaminants

    International Nuclear Information System (INIS)

    The in vitro toxicological index IC50 (the millimolar concentration of compound which inhibits response assay by 50% compared to the solvent control) of 11 water contaminants (acrylamide, atrazine, B[a]P, BPA, 2,4-DAT, 17-αEE, H2O2, 4-OP, sodium bromate, sodium chlorate, sodium nitrate) was evaluated on the human hepatoma (HepG2) cells using three short-term bioassays related to their morbidity status [radiometric RNA synthesis assay (RNA), luminometric ATP assay (ATP), fluorometric Alamar blue assay (AB)]. Among all substances, we were not able to determine atrazine IC50 value whatever the test used. Furthermore, B[a]P was not cytotoxic in the ATP and AB assays. Statistical analysis revealed a correlation between the IC50 values obtained in the three assays. Except with 4-OP, RNA assay was always inhibited at lower concentrations than those required in the other assays, suggesting that this assay is a very sensitive indicator of the presence of toxic compounds. ATP and AB assays responded to a similar pattern. Due to its higher sensitivity and its reliability, RNA synthesis assay using HepG2 cell line provides the most suitable tool for the screening of water contaminants

  6. Laser-induced removal of a dye C.I. Acid Red 87 using n-type WO3 semiconductor catalyst

    International Nuclear Information System (INIS)

    Water contamination by organic substances such as dyes is of great concern worldwide due to their utilization in many industrial processes and environmental concerns. To cater the needs for waste water treatment polluted with organic dyes, laser-induced photocatalytic process was investigated for removal of a dye derivative namely Acid Red 87 using n-type WO3 semiconductor catalyst. The degradation was investigated in aqueous suspensions of tungsten oxide under different experimental conditions using laser instead of conventional UV lamp as an irradiation source. The degradation process was monitored by measuring the change in dye concentration as a function of laser irradiation time by employing UV spectroscopic analysis. The degradation of dye was studied by varying different parameters such as laser energy, reaction pH, substrate concentration, catalyst concentration, and in the presence of electron acceptors such as hydrogen peroxide (H2O2), and potassium bromate (KBrO3). The degradation rates were found to be strongly dependent on all the above-mentioned parameters. Our experimental results revealed that the dye degradation process was very fast (within few minutes) under laser irradiation as compared to conventional setups using broad spectral lamps (hours or days) and this laser-induced photocatalytic degradation method could be an effective means to eliminate the pollutants present in liquid phase. The experience gained through this study could be beneficial for treatment of waste water contaminated with organic dyes and other organic pollutants.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-03-01

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

  8. pH-oscillations in the bromate–sulfite reaction in semibatch and in gel-fed batch reactors

    International Nuclear Information System (INIS)

    The simplest bromate oxidation based pH-oscillator, the two component BrO3−–SO32– flow system was transformed to operate under semibatch and closed arrangements. The experimental preconditions of the pH-oscillations in semibatch configuration were predicted by model calculations. Using this information as guideline large amplitude (ΔpH∼3), long lasting (11–24 h) pH-oscillations accompanied with only a 20% increase of the volume in the reactor were measured when a mixture of Na2SO3 and H2SO4 was pumped into the solution of BrO3− with a very low rate. Batch-like pH-oscillations, similar in amplitude and period time appeared when the sulfite supply was substituted by its dissolution from a gel layer prepared previously in the reactor in presence of high concentration of Na2SO3. The dissolution vs time curve and the pH-oscillations in the semibatch and closed systems were successfully simulated. Due to the simplicity in composition and in experimental technique, the semibatch and batch-like BrO3−–SO32– pH-oscillators may become superior to their CSTR (continuous flow stirred tank reactor) version in some present and future applications

  9. Oxidative Stress in the Carcinogenicity of Chemical Carcinogens

    International Nuclear Information System (INIS)

    This review highlights several in vivo studies utilizing non-genotoxic and genotoxic chemical carcinogens, and the mechanisms of their high and low dose carcinogenicities with respect to formation of oxidative stress. Here, we survey the examples and discuss possible mechanisms of hormetic effects with cytochrome P450 inducers, such as phenobarbital, α-benzene hexachloride and 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane. Epigenetic processes differentially can be affected by agents that impinge on oxidative DNA damage, repair, apoptosis, cell proliferation, intracellular communication and cell signaling. Non-genotoxic carcinogens may target nuclear receptors and induce post-translational modifications at the protein level, thereby impacting on the stability or activity of key regulatory proteins, including oncoproteins and tumor suppressor proteins. We further discuss role of oxidative stress focusing on the low dose carcinogenicities of several genotoxic carcinogens such as a hepatocarcinogen contained in seared fish and meat, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, arsenic and its metabolites, and the kidney carcinogen potassium bromate

  10. Remedial Process Optimization and Green In-Situ Ozone Sparging for Treatment of Groundwater Impacted with Petroleum Hydrocarbons

    Science.gov (United States)

    Leu, J.

    2012-12-01

    A former natural gas processing station is impacted with TPH and BTEX in groundwater. Air sparging and soil vapor extraction (AS/AVE) remediation systems had previously been operated at the site. Currently, a groundwater extraction and treatment system is operated to remove the chemicals of concern (COC) and contain the groundwater plume from migrating offsite. A remedial process optimization (RPO) was conducted to evaluate the effectiveness of historic and current remedial activities and recommend an approach to optimize the remedial activities. The RPO concluded that both the AS/SVE system and the groundwater extraction system have reached the practical limits of COC mass removal and COC concentration reduction. The RPO recommended an in-situ chemical oxidation (ISCO) study to evaluate the best ISCO oxidant and approach. An ISCO bench test was conducted to evaluate COC removal efficiency and secondary impacts to recommend an application dosage. Ozone was selected among four oxidants based on implementability, effectiveness, safety, and media impacts. The bench test concluded that ozone demand was 8 to 12 mg ozone/mg TPH and secondary groundwater by-products of ISCO include hexavalent chromium and bromate. The pH also increased moderately during ozone sparging and the TDS increased by approximately 20% after 48 hours of ozone treatment. Prior to the ISCO pilot study, a capture zone analysis (CZA) was conducted to ensure containment of the injected oxidant within the existing groundwater extraction system. The CZA was conducted through a groundwater flow modeling using MODFLOW. The model indicated that 85%, 90%, and 95% of an injected oxidant could be captured when a well pair is injecting and extracting at 2, 5, and 10 gallons per minute, respectively. An ISCO pilot test using ozone was conducted to evaluate operation parameters for ozone delivery. The ozone sparging system consisted of an ozone generator capable of delivering 6 lbs/day ozone through two ozone

  11. Catalytic discoloring spectrophotometry determination of trace element germanium in Chinese herbal medicine (herba hedyotis)%催化褪色光度法测定中草药白花蛇舌草中的微量锗

    Institute of Scientific and Technical Information of China (English)

    杨慧; 丁良; 张宝淋; 袁丽云; 董晓东

    2015-01-01

    目的:利用催化褪色光度法测定中草药白花蛇舌草中微量元素锗。方法用超声波清洗仪提取中草药白花蛇舌草中微量元素锗,并用催化褪色光度法测定锗元素的含量。研究痕量锗在稀硫酸介质中催化加速溴酸钾、过氧化氢与中性红之间的反应,建立催化光度法测定痕量锗的方法。结果本实验测得中草药白花蛇舌草中无机锗(Ⅳ)含量为0.0248μg/g。结论该法灵敏度、精密度均能满足检测工作的需要。%Objective To explore a catalytic spectrophotometic method for the quantitative determination of trace elements germanium in Chinese herbal medicine (herba hedyotis).Methods Extraction of trace element germanium inherba hedyotis was examined by using ultrasonic cleaning equipment, and the content was determined by catalytic discoloring spectrophotometry. The reaction was studied, trace germanium (IV) could accelerate potassium bromate and hydrogen peroxide oxidize neutral red in H2SO4 medium, the established method could be used to determine catalytic spectrophotometric determination of trace germanium (IV).Results The results of this experiment indicated that inorganic germanium (IV) content in Chinese herbal medicine spreadingherba hedyotis was 0.024 8 μg/g.Conclusion The sensitivity, the precision can meet the needs of the testing work well.

  12. 四种国标测定氨氮方法述评%Evaluation of Four GB Methods about Ammonia Determination

    Institute of Scientific and Technical Information of China (English)

    陈岚

    2014-01-01

    According to practical experience, we evaluate the character of four GB methods about ammonia determination. We improve the determination limit and solve the problem of insufficient oxidant adjunction and high salinity affecting by diluting a small amount of sample. However, if the sample has a high ammonia concentration, salicylic acid method can be adopted instead of Nessler's method to avoid mercury pollution. If the sample has a low ammonia concentration, bromate method can be used to replace phenol method that will overcome the shortcoming of slow reaction speed of the latter. QUAATRO continuous flow analyzer is a better instrument that may be used to replace the above methods.%作者结合工作经验,评述了测定氨氮的四种国家标准的特点,采用少取水样量稀释之,可以提高测定浓度上限,也解决了氧化剂加量不足或盐度大的问题。因而,对高浓度的样品(0.5-50 mg/L)可以用水杨酸法取代纳氏法,避免了后者汞的污染;对低浓度样品(<0.5 mg/L),可以用次溴酸盐法取代苯酚法,克服了后者反应太慢的缺点。QUAATRO连续流动分析仪是可以取代上述方法较好的仪器。

  13. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    Science.gov (United States)

    Qu, Ruijuan; Feng, Mingbao; Wang, Xinghao; Huang, Qingguo; Lu, Junhe; Wang, Liansheng; Wang, Zunyao

    2015-01-01

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters. PMID:26430733

  14. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    Directory of Open Access Journals (Sweden)

    Ruijuan Qu

    Full Text Available Tetrabromobisphenol A (TBBPA is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters.

  15. Zirconium-based metal organic frameworks: Highly selective adsorbents for removal of phosphate from water and urine

    International Nuclear Information System (INIS)

    Phosphate is one of the most concerning compounds in wastewater streams and a main nutrient that causes eutrophication. To eliminate the phosphate pollution, Metal Organic Frameworks (MOFs) are proposed in this study as adsorbents to remove phosphate from water. The zirconium-based MOF, UiO-66, was selected as representative MOF given its exceptional stability in water. To investigate the effect of an amine functional group, UiO-66-NH2 was also prepared using an amine-substituted ligand. The adsorption kinetics and isotherm reveal that UiO-66-NH2 exhibited higher adsorption capacities than UiO-66 possibly due to the amine group. However, the interaction between phosphate and zirconium sites of UiO MOFs might be the primary factor accounting for the phosphate adsorption to UiO MOFs. UiO MOFs also exhibited a high selectivity towards phosphate over other anions such as bromate, nitrite and nitrate. Furthermore, UiO MOFs were found to adsorb phosphate and to completely remove diluted phosphate in urine. We also found that UiO MOFs could be easily regenerated and re-used for phosphate adsorption. These findings suggest that UiO MOFs can be effective and selective adsorbents to remove phosphate from water as well as urine. - Highlights: • UiO-66 as the first type of MOFs was used to remove phosphate from water and urine. • The amine group in UiO MOFs was found to enhance the phosphate adsorption. • UiO-66 exhibited a high adsorption selectivity towards phosphate over other anions. • UiO-66 could be easily regenerated and re-used with 85% regeneration efficiency

  16. Fabrication of CdS/CdTe solar cells with transparent p-type conductive BaCuSeF back contact

    Science.gov (United States)

    Yamamoto, Koichi; Sakakima, Hiroshi; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Wada, Takahiro

    2015-08-01

    BaCuSeF films were applied to CdS/CdTe solar cells as back electrodes. The interfaces between the CdTe and BaCuSeF layers in the CdS/CdTe solar cells with BaCuSeF back contact deposited at substrate temperatures (TS) of 200 and 300 °C were analyzed by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). We clearly observed many dislocations in the CdTe layer in the CdS/CdTe solar cell with the BaCuSeF layer deposited at TS = 300 °C. We also observed a reaction layer of Cu2.72Te2 between the BaCuSeF and CdTe layers in both solar cells. We concluded that (1) the substrate temperature for the pulsed laser deposition of the BaCuSeF layer and (2) the interface between the CdTe and BaCuSeF layers are important factors for the performance of the CdTe solar cells. We obtained high conversion efficiency of 8.31% for a solar cell with a BaCuSeF layer deposited at TS = 200 °C on a CdTe surface etched in a NH3 aqueous solution. The highest conversion efficiency of 9.91% was obtained for a solar cell with a CdTe surface etched in a bromide-bromate solution.

  17. Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

    KAUST Repository

    Wang, Yin

    2014-10-03

    Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

  18. Development of new radiation resistant, fire-retardant cables. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Ko; Morita, Yosuke; Udagawa, Takashi (Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment); Fujimura, Shun-ichi; Oda, Eisuke

    1982-12-01

    For the cables for nuclear facilities, radiation resistance and fire-retardation are severely required. The authors took note of the fact that even in the existing cables for nuclear power plants, their mechanical properties are greatly degraded by the exposure to large dose (for example, 200 Mrad in PWR testing conditions), and attempted the improvement. They employed a new additive, bromated acenaphthylene condensate (con-BACN), which effectively gives radiation resistance and also is a good flame retarder, to be compounded to an insulation material, and examined the characteristics. In this paper, the features of con-BACN and the investigation of fire-retardant EPDM composition are described. As an initial composition, a small amount of zinc white, sulphur, stearic acid, noclac 224 (Ouchi-Shinko Chemicals, Co.), and antimony trioxide, 100 parts of tale and 45 parts of con-BACN were added to 100 parts of EPDM (propylene content 34 %, Japan Synthetic Rubber Co.). As the antiaging agent, it was decided to use phenol series No. 3 as a result of test. The fire-retardant EP rubber-composed cable was produced for trial, its insulation being fabricated, using a Furukawa's pressurized salt bath continuous vulcanizer. The tests of ..gamma..-irradiation, simulated LOCA and combustion were carried out, and the test results are reported. It was indicated that the cable resisted against high dose several times as much as 200 Mrad, and was suitable for the applications, in which the mechanical properties such as bending are required to be maintained after radiation exposure. It was also found that con-BACN was safe, and its properties of decomposition, concentration and acute toxicity were all very low.

  19. Comparative Evaluation of the Nutritional and Sensory Quality of Major Commercial Whole-wheat Breads in Nigerian Market

    Directory of Open Access Journals (Sweden)

    Joel Ndife

    2013-12-01

    Full Text Available The study examined the nutritional, microbial and sensory profile of regularly consumed commercial whole wheat breads in Nigeria in order to offer an insight into the overall quality of these foods. Four major local brands of commercial whole wheat breads (samples A, B, C and D were evaluated. The normal white bread (sample E served as control. Results of the physical properties obtained, showed that the white bread (sample E had higher values for bread volume (2850 cm3 , specific volume (4.38 cm3, hydration capacity (4.50% and compressibility (45% than the whole wheat breads. No trace of bromate was found in all the bread samples. The proximate analyses for the whole wheat bread showed the moisture content to range from (30.64-38.74%, fat (3.5-5.0%, Fibre (2.5-3.5% higher than in white bread (26.40, 3.0 and 1.20% respectively. While the whole wheat breads had lower levels of protein (5.25-6.48%, carbohydrate (45.74-51.25% and energy (249-258 Kcal when compared to white bread of 9.00, 59.40% and 301 Kcal, respectively. The ash and mineral contents of the whole wheat breads were higher than that of white bread. While the viable microbial counts for the whole wheat breads (1.0×102-1.5×10 2 were lower than in the white bread (3.1×102. Generally, the bread samples were within the regulatory specifications and the whole wheat breads were nutritionally superior to the white bread while the white bread had better overall sensory preference than the whole wheat breads.

  20. Development of new radiation resistant, fire-retardant cables

    International Nuclear Information System (INIS)

    For the cables for nuclear facilities, radiation resistance and fire-retardation are severely required. The authors took note of the fact that even in the existing cables for nuclear power plants, their mechanical properties are greatly degraded by the exposure to large dose (for example, 200 Mrad in PWR testing conditions), and attempted the improvement. They employed a new additive, bromated acenaphthylene condensate (con-BACN), which effectively gives radiation resistance and also is a good flame retarder, to be compounded to an insulation material, and examined the characteristics. In this paper, the features of con-BACN and the investigation of fire-retardant EPDM composition are described. As an initial composition, a small amount of zinc white, sulphur, stearic acid, noclac 224 (Ouchi-Shinko Chemicals, Co.), and antimony trioxide, 100 parts of tale and 45 parts of con-BACN were added to 100 parts of EPDM (propylene content 34 %, Japan Synthetic Rubber Co.). As the antiaging agent, it was decided to use phenol series No. 3 as a result of test. The fire-retardant EP rubber-composed cable was produced for trial, its insulation being fabricated, using a Furukawa's pressurized salt bath continuous vulcanizer. The tests of γ-irradiation, simulated LOCA and combustion were carried out, and the test results are reported. It was indicated that the cable resisted against high dose several times as much as 200 Mrad, and was suitable for the applications, in which the mechanical properties such as bending are required to be maintained after radiation exposure. It was also found that con-BACN was safe, and its properties of decomposition, concentration and acute toxicity were all very low. (Wakatsuki, Y.)

  1. Utilization of a Green Brominating Agent for the Spectrophotometric Determination of Pipazethate HCl in Pure Form and Pharmaceutical Preparations

    Directory of Open Access Journals (Sweden)

    Ayman A. Gouda

    2013-01-01

    Full Text Available Five simple, accurate, and sensitive spectrophotometric methods (A–E have been described for the indirect assay of pipazethate HCl (PZT either in pure form or in pharmaceutical preparations. The proposed methods are based on the bromination of pipazethate HCl with a solution of excess bromate-bromide mixture in hydrochloric acid medium and subsequent estimation of the residual bromine by different reaction schemes. In the first three methods (A–C, the determination of the residual bromine is based on its ability to bleach the color of methyl orange, indigo carmine, or thymol blue dyes and measuring the absorbance at 520, 610, and 550 nm for methods A, B, and C, respectively. Methods D and E involves treating the unreacted bromine with a measured excess of iron(II, and the remaining iron(II is complexed with 1,10-phenanthroline, and the increase in absorbance is measured at 510 nm for method D and the resulting iron(III is complexed with thiocyanate and the absorbance is measured at 480 nm for method E. The different experimental parameters affecting the development and stability of the color are carefully studied and optimized. Regression analysis of the Beer-Lambert plots showed good correlation in the concentration ranges of 0.5–8.0 μg . The apparent molar absorptivity, Sandell's sensitivity, detection and quantitation limits were evaluated. The proposed methods have been applied and validated successfully for the analysis of the drug in its pure form and pharmaceutical formulations with mean recoveries of 99.94%–100.15% and relative standard deviation ≤1.53. No interference was observed from a common pharmaceutical adjuvant. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

  2. Titrimetric, spectrophotometric and kinetic methods for the assay of atenolol using bromate–bromide and methyl orange

    Directory of Open Access Journals (Sweden)

    KANAKAPURA BASAVAIAH

    2006-05-01

    Full Text Available Three new methods have been developed for the determination of atenolol in bulk drug and in tablet formulation. The methods are based on the oxidation–bromination reaction of the drug by bromine, generated in situ by the action of acid on a bromate–bromide mixture. In the titrimetric method, the drug is treated with a known excess of bromate–bromide mixture in hydrochloric acid medium, followed by the determination of the unreacted bromine iodometrically. The spectrophotometric method involves the addition of a measured excess of bromate–bromide reagent in hydrochloric acid medium to atenolol, and after ensuring the reaction had gone to completion, the unreacted bromine is treated with a fixed amount of methyl orange, and absorbance measured at 520 nm. The absorbance was found to increase linearly with increasing concentration of atenolol. The kinetic method depends on the existence of a linear relationship between the concentration of the drug and the time of the oxidation–bromination reaction, as indicated by the bleaching of methyl orange acid colour. The working conditions were optimized. The titrimetric method is based on a 1:1 reaction stoichiometry (atenolol:bromate and is applicable over the 3–20 mg range. The spectrophotometric method permits micro determination of the drug (0.5–4.0 mg ml-1with an apparentmolar absorptivity of 4.13x104 lmol-1 cm-1 and detection limit of 0.07 mg ml-1. The kinetic method is applicable in the concentration range 5–25 mg ml-1 with a detection limit of 3.72 mg ml-1. The proposed methods were successfully applied to the determination of atenolol in tablet preparations with mean recoveries of 97.63 to 101.78 %. The reliability of the assay was established by parallel determination by the reference method and by recovery studies using the standard addition technique.

  3. 溴化蓖麻油多元醇合成及其制备的阻燃聚氨酯硬泡性能%The Synthesis of Bromine-containing Castor Oil Polyol and the Flame-retardant Polyurethane Foam Prooerties

    Institute of Scientific and Technical Information of China (English)

    何明; 罗振扬; 史以俊; 顾晓利; 张银萍

    2011-01-01

    A novel bromine-containing castor oil based polyol was prepared via the reaction of glycerin-exchanged castor oil and bromine.Structure of bromation product was analyzed by FT-IR.The basic characters of the polyol, such as viscosity, hydroxyl value and acid value were investigated.The effects of bromine-containing castor oil based polyols on properties of the rigid polyurethane foams, especially on their resistance to combustion, were studied by foam experiment, oxygen index, smoke density and horizontal burning experiments.It was compared with the foam prepared by RB-79 of Albemarle Corporation.It was found that the bromine-containing castor oil based polyols were effective for improving the resistance to combustion of rigid polyurethane foams, having the same effects with the commercial flame retardant RB-79 of Albemarle Corporation.%采用可再生的醇解蓖麻油多元醇为原料,与液溴进行加成反应制备溴化蓖麻油多元醇,通过红外光谱证实发生了溴化反应,并测定了产物粘度、羟值、酸值.通过发泡实验和氧指数、烟密度、水平燃烧等测试手段,考察了溴化蓖麻油基聚氨酯硬泡发泡参数和阻燃性质,并与工业级阻燃荆雅保RB-79制备的聚氨酯硬泡进行比较.结果表明,由溴化蓖麻油多元醇制备的泡沫体现出较好阻燃性能,与RB-79的阻燃效果相当.

  4. Stopped-in-loop flow analysis system for successive determination of trace vanadium and iron in drinking water using their catalytic reactions.

    Science.gov (United States)

    Ayala Quezada, Alejandro; Ohara, Keisuke; Ratanawimarnwong, Nuanlaor; Nacapricha, Duangjai; Murakami, Hiroya; Teshima, Norio; Sakai, Tadao

    2015-11-01

    An automated stopped-in-loop flow analysis (SILFA) system is proposed for the successive catalytic determination of vanadium and iron. The determination of vanadium was based on the p-anisidine oxidation by potassium bromate in the presence of Tiron as an activator to form a reddish dye, which has an absorption maximum at 510 nm. The selectivity of the vanadium determination was greatly improved by adding diphosphate as a masking agent of iron. For the iron determination, an iron-catalyzed oxidative reaction of p-anisidine by hydrogen peroxide with 1,10-phenanthroline as an activator to produce a reddish dye (510 nm) was employed. The SILFA system consisted of two peristaltic pumps, two six-port injection valves, a four-port selection valve, a heater device, a spectrophotometric detector and a data acquisition device. One six-port injection valve was used for the isolation of a mixed solution of standard/sample and reagent to promote each catalytic reaction, and another six-port injection valve was used for switching the reagent for vanadium or iron to achieve selective determination of each analyte. The above mentioned four-port selection valve was used to select standard solutions or sample. These three valves and the two peristaltic pumps were controlled by a built-in programmable logic controller in a touchscreen controller. The obtained results showed that the proposed SILFA monitoring system constituted an effective approach for the selective determination of vanadium and iron. The limits of detection, 0.052 and 0.55 µg L(-1), were obtained for vanadium and iron, respectively. The proposed system was successfully applied to drinking water samples without any preconcentration procedures. PMID:26452899

  5. DRINKING WATER DISINFECTION BYPRODUCTS:CHEMICAL CHARACTERIZATION AND TOXICITY%饮用水消毒副产物:化学特征与毒性

    Institute of Scientific and Technical Information of China (English)

    赵玉丽; 李杏放

    2011-01-01

    Disinfection of drinking water is essential to and effective for the prevention of water-borne diseases.While achieving deactivation of microbial pathogens to minimize the acute risk, an unintentional consequence is the formation of disinfection byproducts (DBPs) resulting from reactions of disinfectants with natural organic materials (NOMs) in water. Epidemiological studies show potential associations of increased risk of bladder cancer and adverse health effects with DBPs. Balancing microbial risk with chemical risk is challenging for public health protection. Currently, the most commonly used disinfectants are chlorine, chlorine dioxide,chloramines and ozone. Here we provide an overview of chemical characterization, toxicity and analytical methods of 10 classes of DBPs, including trihalomethanes ( THMs), haloacefic acids ( HAAs), bromate ( BrO3- ), chlorite ( ClO2- ), haloacetonitriles (HANs), mutagen X (MX), halonitromethane ( HNMs), iodo acids (IAs), N-nitrosodimethylamines (NMs) and halobenzoquinones (HBQs). We will discuss the challenges and opportunities in the research of DBPs and health effects.%饮用水消毒过程中消毒剂与天然有机物(NOMs)反应生成消毒副产物(DBPs).本文针对氯、氯胺、二氧化氯、臭氧4种主要消毒方式产生的消毒副产物,综述了10类DBPs的化学特性、毒性和分析方法.具体包括:三卤甲烷(THMs)、卤乙酸(HAAs)、溴酸盐(BrO3-)、亚氯酸盐(CIO2-)、卤乙腈(HANs)、致诱变化合物(MX)、卤代硝基甲烷(HNMs)、碘代酸(Ias)、亚硝胺(NMs)以及卤代对苯醌(HBQs).

  6. Zirconium-based metal organic frameworks: Highly selective adsorbents for removal of phosphate from water and urine

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Kun-Yi Andrew, E-mail: linky@nchu.edu.tw [Department of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung, Taiwan (China); Chen, Shen-Yi [Department of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung, Taiwan (China); Jochems, Andrew P. [New Mexico Bureau of Geology & Mineral Resources and New Mexico Institute of Mining & Technology, Socorro, NM (United States)

    2015-06-15

    Phosphate is one of the most concerning compounds in wastewater streams and a main nutrient that causes eutrophication. To eliminate the phosphate pollution, Metal Organic Frameworks (MOFs) are proposed in this study as adsorbents to remove phosphate from water. The zirconium-based MOF, UiO-66, was selected as representative MOF given its exceptional stability in water. To investigate the effect of an amine functional group, UiO-66-NH2 was also prepared using an amine-substituted ligand. The adsorption kinetics and isotherm reveal that UiO-66-NH2 exhibited higher adsorption capacities than UiO-66 possibly due to the amine group. However, the interaction between phosphate and zirconium sites of UiO MOFs might be the primary factor accounting for the phosphate adsorption to UiO MOFs. UiO MOFs also exhibited a high selectivity towards phosphate over other anions such as bromate, nitrite and nitrate. Furthermore, UiO MOFs were found to adsorb phosphate and to completely remove diluted phosphate in urine. We also found that UiO MOFs could be easily regenerated and re-used for phosphate adsorption. These findings suggest that UiO MOFs can be effective and selective adsorbents to remove phosphate from water as well as urine. - Highlights: • UiO-66 as the first type of MOFs was used to remove phosphate from water and urine. • The amine group in UiO MOFs was found to enhance the phosphate adsorption. • UiO-66 exhibited a high adsorption selectivity towards phosphate over other anions. • UiO-66 could be easily regenerated and re-used with 85% regeneration efficiency.

  7. Determination of trace uranium by resonance fluorescence method coupled with photo-catalytic technology and dual cloud point extraction.

    Science.gov (United States)

    Li, Jiekang; Li, Guirong; Han, Qian

    2016-12-01

    In this paper, two kinds of salophens (Sal) with different solubilities, Sal1 and Sal2, have been respectively synthesized, and they all can combine with uranyl to form stable complexes: [UO2(2+)-Sal1] and [UO2(2+)-Sal2]. Among them, [UO2(2+)-Sal1] was used as ligand to extract uranium in complex samples by dual cloud point extraction (dCPE), and [UO2(2+)-Sal2] was used as catalyst for the determination of uranium by photocatalytic resonance fluorescence (RF) method. The photocatalytic characteristic of [UO2(2+)-Sal2] on the oxidized pyronine Y (PRY) by potassium bromate which leads to the decrease of RF intensity of PRY were studied. The reduced value of RF intensity of reaction system (ΔF) is in proportional to the concentration of uranium (c), and a novel photo-catalytic RF method was developed for the determination of trace uranium (VI) after dCPE. The combination of photo-catalytic RF techniques and dCPE procedure endows the presented methods with enhanced sensitivity and selectivity. Under optimal conditions, the linear calibration curves range for 0.067 to 6.57ngmL(-1), the linear regression equation was ΔF=438.0 c (ngmL(-1))+175.6 with the correlation coefficient r=0.9981. The limit of detection was 0.066ngmL(-1). The proposed method was successfully applied for the separation and determination of uranium in real samples with the recoveries of 95.0-103.5%. The mechanisms of the indicator reaction and dCPE are discussed. PMID:27380304

  8. The impact of lymphocyte isolation on induced DNA damage in human blood samples measured by the comet assay.

    Science.gov (United States)

    Bausinger, Julia; Speit, Günter

    2016-09-01

    The comet assay is frequently used in human biomonitoring for the detection of exposure to genotoxic agents. Peripheral blood samples are most frequently used and tested either as whole blood or after isolation of lymphocytes (i.e. peripheral blood mononuclear cells, PBMC). To investigate a potential impact of lymphocyte isolation on induced DNA damage in human blood samples, we exposed blood ex vivo to mutagens with different modes of genotoxic action. The comet assay was performed either directly with whole blood at the end of the exposure period or with lymphocytes isolated directly after exposure. In addition to the recommended standard protocol for lymphocyte isolation, a shortened protocol was established to optimise the isolation procedure. The results indicate that the effects of induced DNA strand breaks and alkali-labile sites induced by ionising radiation and alkylants, respectively, are significantly reduced in isolated lymphocytes. In contrast, oxidative DNA base damage (induced by potassium bromate) and stable bulky adducts (induced by benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide; BPDE) seem to be less affected. Our findings suggest that in vivo-induced DNA damage might also be reduced in isolated lymphocytes in comparison with the whole blood depending of the types of DNA damage induced. Because only small genotoxic effects can generally be expected in human biomonitoring studies with the comet assay after occupational and environmental exposure to genotoxic agents, any loss might be relevant and should be avoided. The possibility of such effects and their potential impact on variability of comet assay results in human biomonitoring should be considered when performing or evaluating such kind of studies. PMID:27154923

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

    Science.gov (United States)

    Florentin, Arnaud; Hautemanière, Alexis; Hartemann, Philippe

    2011-11-01

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

  10. 天津开发区净水厂三期工程紫外线消毒系统应用研究%Application study on UV disinfection system in the third stage project of Tianjin development zone Water Treatment Plant

    Institute of Scientific and Technical Information of China (English)

    聂雪彪; 刘文君; 何凤华

    2011-01-01

    The UV - chlorine disinfection process was employed in the third stage project in Tianjin development zone water treatment plant. The production water and pipe - network water were tested, and the results showed: Cryptozoite, Giardia, coronavirus and adenovirus were not found; the coliform, total plate count, HPC (Heterotrophic bacteria count), bromate, haloacetic acids, and trihalomethanes in production water and pipe-network water all met the standards; when UVT (UV transmittance) in UV disinfection reactor was relatively high (UVT=95%), the power of UV disinfection equipment could be lowered; there was still some space for the decrease of chlorine dosage in the UV-chlorine disinfection process.%天津开发区净水厂三期工程采用紫外线联合氯消毒工艺,对主要工艺出水及管网水进行检测,未检出隐孢子虫、贾第鞭毛虫、冠状病毒和腺病毒;出厂水及管网水中总大肠菌群、菌落总数、HPC(Heterotrophic bacteria count,异养菌计数),以及溴酸盐、卤乙酸、三卤甲烷等理化指标均达到相关标准要求;紫外线反应器进水UVT(UV transmittance,紫外透光率)较高时(如UVT=95%),可降低紫外线消毒设备功率;联合消毒的加氯量经初步探究有一定的降低空间.

  11. In vivo Comet assay on isolated kidney cells to distinguish genotoxic carcinogens from epigenetic carcinogens or cytotoxic compounds.

    Science.gov (United States)

    Nesslany, Fabrice; Zennouche, Nadia; Simar-Meintières, Sophie; Talahari, Ismaïl; Nkili-Mboui, Esther-Nadège; Marzin, Daniel

    2007-06-15

    The objective of this study was to determine the ability of the alkaline in vivo Comet assay (pH>13) to distinguish genotoxic carcinogens from epigenetic carcinogens when performed on freshly isolated kidney cells and to determine the possible interference of cytotoxicity by assessing DNA damage induced by renal genotoxic, epigenetic or toxic compounds after enzymatic isolation of kidney cells from OFA Sprague-Dawley male rats. The ability of the Comet assay to distinguish (1) genotoxicity versus cytotoxicity and (2) genotoxic versus non-genotoxic (epigenetic) carcinogens, was thus investigated by studying five known genotoxic renal carcinogens acting through diverse mechanisms of action, i.e. streptozotocin, aristolochic acids, 2-nitroanisole, potassium bromate and cisplatin, two rodent renal epigenetic carcinogens: d-limonene and ciclosporine and two nephrotoxic compounds: streptomycin and indomethacin. Animals were treated once with the test compound by the appropriate route of administration and genotoxic effects were measured at the two sampling times of 3-6 and 22-26h after treatment. Regarding the tissue processing, the limited background level of DNA migration observed in the negative control groups throughout all experiments demonstrated that the enzymatic isolation method implemented in the current study is appropriate. On the other hand, streptozotocin, 20mg/kg, used as positive reference control concurrently to each assay, caused a clear increase in the mean Olive Tail Moment median value, which allows validating the current methodology. Under these experimental conditions, the in vivo rodent Comet assay demonstrated good sensitivity and good specificity: all the five renal genotoxic carcinogens were clearly detected in at least one expression period either directly or indirectly, as in the case of cisplatin: for this cross-linking agent, the significant decrease in DNA migration observed under standard electrophoresis conditions was clearly amplified

  12. Reclaimed water quality during simulated ozone-managed aquifer recharge hybrid

    KAUST Repository

    Yoon, Min

    2014-06-17

    A synergistic hybrid of two treatment processes, managed aquifer recharge (MAR) combined with ozonation, was proposed for wastewater reclamation and water reuse applications. Batch reactor and soil-column experiments were performed to evaluate reclaimed water quality using various chemical and bacterial analyses. The ozone process was optimized at low ozone dose (0.5 mg O3/mg DOC) based on the control of N-nitrosodimethylamine (<5 ng L-1) and bromate (<10 μg L-1), and applied prior to (i.e., O3-MAR) and after MAR (i.e., MAR-O3). This work demonstrates that effluent organic matter (EfOM) and trace organic contaminants (TOrCs) are effectively removed during the hybrid process of MAR combined ozonation, compared to MAR only. Based on fluorescence excitation-emission matrices analyses, both MAR and ozonation reduce soluble microbial (protein-like) products while only ozonation contributes in reducing humic and fulvic substances. Even at low ozone dose of 0.5 mg O3/mg DOC, the O3-MAR hybrid significantly reduced UV absorbance by ≥2 m-1, BDOC by ≥64 %, and total (Σ) TOrC concentrations by ≥70 % in the effluent water quality. However, no significant improvement (<10 %) in the removal of Σ16 TOrC concentrations was observed for the increased ozone dose at 1.0 mg O3/mg DOC during MAR combined ozonation processes. Overall, O3-MAR was effective by 10-30 % in treating effluent water than MAR based on DOC, UV254 nm EfOM, TOrC and bacterial analyses. In addition, MAR-O3 was better than O3-MAR for the reduction of fluorescence (close MQ), TOrCs (≥74 %) and total bacteria cell concentrations (>3 log reduction). Therefore, implementing MAR prior to ozonation appears to remove the bio-amenable compounds that react rapidly with ozone, thereby reducing oxidant demand and treatment efficiency. © 2014 Springer-Verlag Berlin Heidelberg.

  13. Enhanced formation of disinfection byproducts in shale gas wastewater-impacted drinking water supplies.

    Science.gov (United States)

    Parker, Kimberly M; Zeng, Teng; Harkness, Jennifer; Vengosh, Avner; Mitch, William A

    2014-10-01

    The disposal and leaks of hydraulic fracturing wastewater (HFW) to the environment pose human health risks. Since HFW is typically characterized by elevated salinity, concerns have been raised whether the high bromide and iodide in HFW may promote the formation of disinfection byproducts (DBPs) and alter their speciation to more toxic brominated and iodinated analogues. This study evaluated the minimum volume percentage of two Marcellus Shale and one Fayetteville Shale HFWs diluted by fresh water collected from the Ohio and Allegheny Rivers that would generate and/or alter the formation and speciation of DBPs following chlorination, chloramination, and ozonation treatments of the blended solutions. During chlorination, dilutions as low as 0.01% HFW altered the speciation toward formation of brominated and iodinated trihalomethanes (THMs) and brominated haloacetonitriles (HANs), and dilutions as low as 0.03% increased the overall formation of both compound classes. The increase in bromide concentration associated with 0.01-0.03% contribution of Marcellus HFW (a range of 70-200 μg/L for HFW with bromide = 600 mg/L) mimics the increased bromide levels observed in western Pennsylvanian surface waters following the Marcellus Shale gas production boom. Chloramination reduced HAN and regulated THM formation; however, iodinated trihalomethane formation was observed at lower pH. For municipal wastewater-impacted river water, the presence of 0.1% HFW increased the formation of N-nitrosodimethylamine (NDMA) during chloramination, particularly for the high iodide (54 ppm) Fayetteville Shale HFW. Finally, ozonation of 0.01-0.03% HFW-impacted river water resulted in significant increases in bromate formation. The results suggest that total elimination of HFW discharge and/or installation of halide-specific removal techniques in centralized brine treatment facilities may be a better strategy to mitigate impacts on downstream drinking water treatment plants than altering

  14. Efficiency and energy requirements for the transformation of organic micropollutants by ozone, O3/H2O2 and UV/H2O2.

    Science.gov (United States)

    Katsoyiannis, Ioannis A; Canonica, Silvio; von Gunten, Urs

    2011-07-01

    The energy consumptions of conventional ozonation and the AOPs O(3)/H(2)O(2) and UV/H(2)O(2) for transformation of organic micropollutants, namely atrazine (ATR), sulfamethoxazole (SMX) and N-nitrosodimethylamine (NDMA) were compared. Three lake waters and a wastewater were assessed. With p-chlorobenzoic acid (pCBA) as a hydroxyl radical ((•)OH) probe compound, we experimentally determined the rate constants of organic matter of the selected waters for their reaction with (•)OH (k(OH,DOM)), which varied from 2.0 × 10(4) to 3.5 × 10(4) L mgC(-1) s(-1). Based on these data we calculated (•)OH scavenging rates of the various water matrices, which were in the range 6.1-20 × 10(4) s(-1). The varying scavenging rates influenced the required oxidant dose for the same degree of micropollutant transformation. In ozonation, for 90% pCBA transformation in the water with the lowest scavenging rate (lake Zürich water) the required O(3) dose was roughly 2.3 mg/L, and in the water with the highest scavenging rate (Dübendorf wastewater) it was 13.2 mg/L, corresponding to an energy consumption of 0.035 and 0.2 kWh/m(3), respectively. The use of O(3)/H(2)O(2) increased the rate of micropollutant transformation and reduced bromate formation by 70%, but the H(2)O(2) production increased the energy requirements by 20-25%. UV/H(2)O(2) efficiently oxidized all examined micropollutants but energy requirements were substantially higher (For 90% pCBA conversion in lake Zürich water, 0.17-0.75 kWh/m(3) were required, depending on the optical path length). Energy requirements between ozonation and UV/H(2)O(2) were similar only in the case of NDMA, a compound that reacts slowly with ozone and (•)OH but is transformed efficiently by direct photolysis. PMID:21645916

  15. An assessment of the influence of multiple stressors on the Vaal River, South Africa

    Science.gov (United States)

    Wepener, V.; van Dyk, C.; Bervoets, L.; O'Brien, G.; Covaci, A.; Cloete, Y.

    community structures. This was related to decreased fish health as demonstrated by increased oxidative stress due to exposure to metals such as copper and nickel as well as organic pollutants such as PCBs, HCHs and bromated flame retardants. This study clearly demonstrates the importance of the inclusion of higher tier assessment endpoints to elucidate the effects of multiple stressors in aquatic ecosystems. The study further allowed for the identification of specific effect endpoints that need to be included in future monitoring programmes such as viral immunoassays.

  16. Organic–inorganic heteropoly blue based on Dawson-type molybdosulfate and organic dye and its characterization and application in electrocatalysis

    International Nuclear Information System (INIS)

    , bromate and hydrogen peroxide in acidic (1 M H2SO4) aqueous solution

  17. Kinetic resolution of racemic mixtures in gel media

    Science.gov (United States)

    Petrova, Rositza Iordanova

    The goal of this research was to investigate the effect of chiral gels on the chiral crystal nucleation and growth and assess the gels' potential as media for kinetic separation of racemic mixtures. The morphologies of asparagine monohydrate and sodium bromate crystals grown in different gel media were examined in order to discern the effect of gel structure and density on the relative growth rates of those materials. Different crystal habits were observed when the gel chemical composition, density and solute concentration were varied. These studies showed that the physical properties of the gel, such as gel density and pore size, as well as its chemical composition affect the crystal habit. The method of kinetic resolution in gel media was first applied to sodium chlorate, which is achiral in solution but crystallizes in a chiral space group. Crystallization in agarose gels yielded an enantiomorphic bias, the direction and magnitude of which could be affected by changing the temperature or by the addition of an achiral cosolvent. Aqueous gels at 6°C produced crystalline mixtures enriched with the d-enantiomorph, while crystallization under MeOH diffusion favored l-crystals. Optimized conditions yielded e.e. of 53% of l-enantiomorph. The method was next applied to the organic molecular crystals of asparagine monohydrate and threonine. Asparagine monohydrate growth in aqueous agarose and iota-carrageenan gels produced crystal mixtures enriched with D-enantiomer. The degree of resolution was higher when the total amount of asparagine crystallized was low. The success of the resolution depends strongly on the concentrations of solute and the geling substance. Growth from agarose gels yielded e.e. of 44% under optimized conditions. The same method was applied to the resolution of Thr, albeit with modest success. In an effort to improve the resolution of asparagine monohydrate, agarose was synthetically modified by esterifying its side chains with homochiral asparagyl

  18. Development of sustainable Palladium-based catalysts for removal of persistent contaminants from drinking water

    Science.gov (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

  19. Determination of Anions in High Chloride Matrix by Ion Chromatography with Pre Online Sample Preparation Technique%谱睿在线除氯技术检测高氯水样中的阴离子

    Institute of Scientific and Technical Information of China (English)

    张夕虎; 刘肖

    2011-01-01

    We developed a method in which Dionex "Pre" online sample preparation technique was used to remove chloride by Ag cartridge and Na cartridge. This method is applicable to a wide range of samples and is simpler than offline approach. Each Ag cartridge carries on 400 consecutive injections (25 microlitre each) of 1% NaCl solution, and the removal efficiency is still above 99%. The separation of anions was carried out by high capacity hydroxide selectivity IonPac ASll-HC gradient separation column while Eluent Generator was employed to generate gradient KOH eluent online automatically. Two valves were switched to finish the injection. The system removes chloride well online for different matrix as analysis grade salt and sodium chloride. The detection limits of bromate, chlorate, chlorite, nitrite, nitrate and sulfate are less than 10μg/L, and the recoveries are between 80% and 110%. This method holds the advantages of easy-operation, good reproducibility, lower operation cost etc and is more convenient than off-line approach.%采用戴安公司谱睿(Pre)在线样品前处理技术,使用高容量在线Ag柱和Na柱,开发出了一种柱前去除高氯基体中氯离子的在线分析方法.操作简便,且适用样品范围广;不更换Ag柱可耐受10g/L NaCl基体,25μL连续进样400针,氯离子去除效率可保持在99%以上.系统选用高容量IonPac AS11-HC氢氧根体系阴离子交换色谱柱,在线淋洗液自动发生装置进行梯度淋洗,用抑制型电导检测.对食盐、分析纯氯化钠等不同基体进行检测,可实现样品在线除氯,并可检测其中不高于10μg/L的溴酸根、氯酸根、亚硝酸根、硝酸根和硫酸根等离子.不同离子校准曲线相关系数均在99.8%以上,加标回收率为80%~110%.该技术具有操作简单、可重复性强、方法新颖等特点,解决了以往高氯基体检测成本过高、适用范围有限、前处理操作复杂等问题.

  20. Recent advances in drinking water disinfection: successes and challenges.

    Science.gov (United States)

    Ngwenya, Nonhlanhla; Ncube, Esper J; Parsons, James

    2013-01-01

    Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality

  1. PERFIL DA QUALIDADE DAS ÁGUAS DE POÇOS EM ADAMANTINA SP, BRASIL

    Directory of Open Access Journals (Sweden)

    LOURENCETTI, Josiane

    2015-11-01

    Full Text Available The increasing use of underground water sources for the supply of the water demand of the various users takes place mainly the advantages presented by this water feature, as the natural filtering, the decrease in steps of treatment and the absence of losses by evaporation. An important factor in the choice of source for abstraction is the quality of groundwater, which according to the purpose of use must meet the drinking water standards set by the Ministry of health, in order to prevent the occurrence of diseases. The objective of this work was to verify the quality of groundwater in the municipality of Adamantina-SP, through information from 37 wells granted and registered in the DAEE (Department of water and Power of PresidentePrudente, containing qualitative analysis results of the water, in the period from 2006 to 2012. The Surfer software and Excel were used in the preparation of thematic maps and graphics generation.In verifying the quality of water potability standards were adopted and organoleptic laid down in ordinance No. 2,914/2011 the Ministry of health. The results indicated values in the default limit of drinking in a well for chrome, in six wells to lead by three wells to manganese in two for the metal and, for substances and chloride bromate in a well. Has been verified as many potential sources of contamination of underground water source in the basin of Tocantins stream, requiring deeper studies and monitoring of specific points to identify point sources of contamination. A crescente utilização dos mananciais subterrâneos para o suprimento da demanda de água dos diversos usuários decorre principalmente das vantagens apresentadas por este recurso hídrico, como a filtragem natural, a diminuição nas etapas de tratamento e, a inexistência de perdas por evaporação. Um fator importante na escolha do manancial para a captação é a qualidade da água subterrânea, que de acordo com a finalidade do uso deve atender aos

  2. 宽浓度范围水碘的碱性高锰酸钾氧化光度测定方法研究%Method for the determination of broad concentration range of iodide in drinking water by spectrophotometry with alkaline potassium permanganate oxidation

    Institute of Scientific and Technical Information of China (English)

    张亚平; 黄嫣红; 林丽卿

    2009-01-01

    water. Results The linear range of the calibration curve of the new method for iodine was 0-1200 μg/L and the linear correlative coefficient was 0.9998. The detection limit for iodine was 4 μg/L. Results of 6 times repeated determination of water samples with iodine concentration of 76.6, 207.8, 560.4 μg/L showed that the relative standard deviations(RSD) were all under 1%. The recovery of standard addition for iodine added in 8 water samples of different iodide concentration levels was 97.0% (485.2/500.0) - 102.5% (102.5/100.0). Interference of hexavalent chromium(Cr~(6+)) in water was eliminated when treated with ferrous reagent. Interference of bromate (BrO_3~-) in water was eliminated when treated with potassium bromide and nitrite sodium reagent. Zero point two mg/L Cr~(6+), 0.1 mg/L BrO_3~- in water were noninterference. Conclusion This method can be easily performed with good precision and accuracy and has broad detection concentration range, which is suitable for measuring iodide in drinking water.