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Bromate is receiving increased attention as a typical disinfection by-product in aquatic environments, but bromate toxicity tests on invertebrate such as Brachionus calyciflorus rotifer are inadequate. In the present study, the long-term toxicity tests on B. calyciflorus were performed during 21 days under the exposure of different bromate concentrations and two algal density conditions. Furthermore, we evaluated the feeding behaviors of the rotifers under the impact of bromate. The maximum population density of rotifers was significantly reduced at 100 and 200 mg/L bromate exposure at the two algal density conditions. However, we observed that the maximum population density and population growth rate of rotifers were higher at 3.0 × 106 cells/mL algal density than those at 1.0 × 106 cells/mL under the same conditions of bromate exposure. These results suggest that higher food density may have alleviated the negative effects of bromate on rotifers. Meanwhile, the ingestion rate at an algal density of 3.0 × 106 cells/mL was higher than that at 1.0 × 106 cells/mL. The present study provides a basic reference to comprehensively evaluate the toxic effects of bromate on aquatic organisms. [ABSTRACT FROM AUTHOR]

As disinfection is employed extensively, disinfection by-product bromate has become an emerging environmental issue due to its carcinogenic toxicity. For developing an effective alternative approach for reducing bromate, cobalt and nickel-based Prussian Blue (PB) analogues are proposed here for incorporating a convenient reducing agent, NaBH4 (i.e., a H2-rich reagent) for reducing bromate to bromide as cobalt and nickel are recognized as effective metals for catalyzing hydrolysis of NaBH4, and PB exhibits versatile catalytic activity. While CoPB and NiPB are comprised of the same crystalline structure, CoPB exhibits slightly higher specific surface area, more reductive surface, and more superior electron transfer than NiPB, enabling CoPB to accelerate bromate reduction. CoPB also exhibits a higher affinity towards NaBH4 than NiPB based on density functional theory calculations. Moreover, CoPB also exhibits a relatively low activation energy (i.e., 59.5 kJ/mol) of bromate reduction than NiPB (i.e., 63.2 kJ/mol). Furthermore, bromate reduction by CoPB and NiPB could be also considerably enhanced under acidic conditions, and CoPB and NiPB could still effectively remove bromate even in the presence of nitrate, sulfate and phosphate. CoPB and NiPB are also validated to be recyclable for reducing bromate, indicating that CoPB and NiPB are promising heterogeneous catalysts for reducing bromate. [ABSTRACT FROM AUTHOR]

In this study, the spent bleaching earth carbon (SBE@C) was modified with iron to obtain the iron-modified spent bleaching earth carbon (defined as FexOy-SBE@C) to remove bromate. The pseudo-second-order kinetic model and Langmuir model could well fit the bromate removal process. When the temperature was increased from 25 to 45 °C, bromate removal efficiency increased, and FexOy-SBE@C exhibited the highest bromate removal capacity of 521.82 mg/g at 45 °C. The effect of coexisting anions was investigated, and their adverse effects decreased in the order of PO43->NO3->SO42-. The higher the concentration of coexisting ions, the greater their inhibitory effect on bromate removal. By studying the effect of pH, it was found that the bromate removal was the highest at pH = 3. Characterization analysis confirmed that the iron was successfully loaded on the surface of SBE@C. The main mechanism for bromate removal by FexOy-SBE@C was the reduction of zero-valent iron and divalent iron with bromate to form the bromide ion. Overall, FexOy-SBE@C is a high-performance material for bromate removal. [ABSTRACT FROM AUTHOR]

This work presents a collaboration between the so-called Gasset Service Association (responsible for providing drinking water to 100,000 inhabitants from a surface water reservoir) and researchers from the University of Castilla-La Mancha (Spain). The main aim of this work was providing a comprehensive characterization of the formation and removal of disinfection by-products in a real drinking water treatment plant (DWTP) and water distribution network. According to the results obtained, it can be stated that bromate is formed on the pre-oxidation stage and it is not eliminated throughout the DWTP; meanwhile, total organic carbon is partially removed on the clarification process. Moreover, it demonstrates the key role of the residence time and the type of water storage throughout the distribution network (either in pipes or in tanks) due to the combined effect of, at least, four overlapped mechanisms: THMs chemical generation, air stripping, hydrolysis and biological removal. This comprehensive view of the drinking water production and distribution network represents an excellent framework for allowing the improvement in the drinking water quality for a very common water production case study: a medium-size city fed by a surface water source. [ABSTRACT FROM AUTHOR]

A sensitive bromate sensor was developed using nickel phthalocyanine multi-walled carbon nanotubes nanocomposite modified on a glassy carbon electrode. The NiPcMWCNTs nanocomposite was prepared from nickel nanoparticles, phthalocyanine, and functionalized MWCNTs via ultrasonication. UV–visible spectroscopy, SEM, XRD, TEM, and EDX techniques were used to verify the successful fabrication of the nanomaterials. The results of the EIS and CV experiments conducted in 5 mM K3(Fe(CN)6/K4(Fe(CN)6 made in 0.1 M of PBS (pH 7) revealed that the NiPcMWCNTs/GCE exhibited higher current response, faster electron transfer, and high specific capacitance compared to other electrodes. The electrochemical reduction of bromate was actualized in 0.1 M H2SO4 (pH 1) using EIS and SWV techniques. Using the EIS technique, an LoD of 6.72 μM was obtained with a sensitivity of 483.7 μA μM−1 over a linear dynamic range (LDR) of 24–100 μM. Whereas, with the SWV technique, a lower LoD (1.47 μM) was obtained with a higher sensitivity (1293 μA μM−1) over an LDR of 12–56 μM. The developed sensor was characterized by good selectivity, high stability (95.5%), and good reproducibility (% RSD; 3.5%). The fabricated sensor was effectively used to detect bromate in bread samples with a good recovery rate, demonstrating the practical application of the sensor to detect bromate in real samples (bread). [ABSTRACT FROM AUTHOR]

Bromate (BrO3−) and ammonia nitrogen (NH4+) are both typical environmental pollutants: BrO3− has been categorized as one of the Group 2B carcinogen by IARC; an excess of NH4+ might result in the eutrophication of water. The existence of NH4+ could inhibit the transformation of bromide (Br−) to bromate (BrO3−). However, the interaction of NH4+ and BrO3− during the removal process is not clear. This study intends to disclose the mutual relationships of ammonia nitrogen and bromate ions under UV irradiation or UV/TiO2 conditions. Without UV irradiation, BrO3− and NH4+ were both stable even under the presentation of each other. Under UV irradiation or UV/TiO2 conditions, BrO3− and NH4+ promoted the degradation of each other, showing the synergistic degradation mechanism. In the neutral environment, both of BrO3− and NH4+ could be transformed effectively. Furthermore, NH4+ accelerated the transformation of BrO3− to Br− at the reaction beginning and the existence of BrO3− is beneficial for the transformation of NH4+ to N2. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the previous advances, current challenges, and future opportunities for the research of catalytic reduction of water pollutants. We present five case studies on the development of palladium-based catalysts for nitrate, chlorate, and perchlorate reduction with hydrogen gas under ambient conditions. We emphasize the realization of new functionalities through the screening and design of catalytic metal sites, including (i) platinum group metal (PGM) nanoparticles, (ii) the secondary metals for improving the reaction rate and product selectivity of nitrate reduction, (iii) oxygen-atom-transfer metal oxides for chlorate and perchlorate reduction, and (iv) ligand-enhanced coordination complexes for substantial activity enhancement. We also highlight the facile catalyst preparation approach that brought significant convenience to catalyst optimization. Based on our own studies, we then discuss directions of the catalyst research effort that are not immediately necessary or desirable, including (1) systematic study on the downstream aspects of under-developed catalysts, (2) random integration with hot concepts without a clear rationale, and (3) excessive and decorative experiments. We further address some general concerns regarding using H2 and PGMs in the catalytic system. Finally, we recommend future catalyst development in both “fundamental” and “applied” aspects. The purpose of this perspective is to remove major misconceptions about reductive catalysis research and bring back significant innovations for both scientific advancements and engineering applications to benefit environmental protection. [ABSTRACT FROM AUTHOR]

Kinetic investigation of Ru(III) catalyzed oxidation of menthol in an acidified solution of potassium bromate in the presence of Hg(OAc)2 as a scavenger of bromine intermediate has been studied. The reaction exhibits zero order kinetics with respect to KBrO3. While first order kinetics with respect to menthol and Ru(III) respectively. Hydrogen ion does not affect the rate but rate is enhanced by ionic strength. The influence of Hg(OAc)2 on the rate was found to be insignificant. Menthone as the oxidation product of menthol has been confirmed spectrally. The proposed mechanism involves slow and rate-controlling disproportionate of a transient complex formed between reactive species of Ru(III) and menthol. The various activation parameter such as energy of activation (∆E)#, Arrhenius factor (A), and entropy of activation (∆S)# were calculated. The rate law derived on the basis of experimental data corresponds well with the proposed mechanism. [ABSTRACT FROM AUTHOR]

Bromide in water can form undesirable by-products such as bromate when treated by ozonation during drinking water production. The maximum contaminant level (MCL) for bromate is 10 µg/L in most countries because it is suspected of being carcinogenic. In this paper, the geographical distribution of bromide concentration in Croatian groundwater is presented covering the Pannonian basin and the Dinarides (Adriatic Sea). Groundwater in Croatian wellfields predominantly has a bromide content of less than 50 µg/L and thus belongs to the group with low potential for bromate formation. Waters with higher bromide concentrations were found mainly in the coastal regions of Croatia, probably due to seawater intrusion. In addition, bromide concentration showed a positive correlation of 0.6 with conductivity, chloride, and sodium. In addition, the potential of 123 groundwaters analyzed in this study to form bromate when treated with ozone was evaluated using models available in the literature. Analysis of water from Croatian wellfields indicated that the potential for bromate formation above the MCL during ozonation was relatively low. The models used from the literature predicted quite different values of bromate concentration when applied to the same water, with some values exceeding those theoretically possible. Selected models may be useful as a general warning of possible bromate formation. [ABSTRACT FROM AUTHOR]

Bromate, classified as a EU CLP 1B carcinogen, is a typical by-product of the disinfection of drinking and swimming pool water. The aim of this study was (a) to provide data on the occurrence of bromate in pool water, (b) to re-evaluate the carcinogenic MOA of bromate in the light of existing data, (c) to assess the possible exposure to bromate via swimming pool water and (d) to inform the derivation of cancer risk-related bromate concentrations in swimming pool water. Measurements from monitoring analysis of 229 samples showed bromate concentrations in seawater pools up to 34 mg/L. A comprehensive non-systematic literature search was done and the quality of the studies on genotoxicity and carcinogenicity was assessed by Klimisch criteria (Klimisch et al., Regul Toxicol Pharmacol 25:1–5, 1997) and SciRAP tool (Beronius et al., J Appl Toxicol, 38:1460–1470, 2018) respectively. Benchmark dose (BMD) modeling was performed using the modeling average mode in BMDS 3.1 and PROAST 66.40, 67 and 69 (human cancer BMDL10; EFSA 2017). For exposure assessment, data from a wide range of sources were evaluated for their reliability. Different target groups (infants/toddlers, children and adults) and exposure scenarios (recreational, sport-active swimmers, top athletes) were considered for oral, inhalation and dermal exposure. Exposure was calculated according to the frequency of swimming events and duration in water. For illustration, cancer risk-related bromate concentrations in pool water were calculated for different target groups, taking into account their exposure using the hBMDL10 and a cancer risk of 1 in 100,000. Convincing evidence was obtained from a multitude of studies that bromate induces oxidative DNA damage and acts as a clastogen in vitro and in vivo. Since statistical modeling of the available genotoxicity data is compatible with both linear as well as non-linear dose–response relationships, bromate should be conservatively considered to be a non-threshold carcinogen. BMD modeling with model averaging for renal cancer studies (Kurokawa et al., J Natl. Cancer Inst, 1983 and 1986a; DeAngelo et al., Toxicol Pathol 26:587–594, 1998) resulted in a median hBMDL10 of 0.65 mg bromate/kg body weight (bw) per day. Evaluation of different age and activity groups revealed that top athletes had the highest exposure, followed by sport-active children, sport-active adults, infants and toddlers, children and adults. The predominant route of exposure was oral (73–98%) by swallowing water, followed by the dermal route (2–27%), while the inhalation route was insignificant (< 0.5%). Accepting the same risk level for all population groups resulted in different guidance values due to the large variation in exposure. For example, for an additional risk of 1 in 100,000, the bromate concentrations would range between 0.011 for top athletes, 0.015 for sport-active children and 2.1 mg/L for adults. In conclusion, the present study shows that health risks due to bromate exposure by swimming pool water cannot be excluded and that large differences in risk exist depending on the individual swimming habits and water concentrations. [ABSTRACT FROM AUTHOR]

The effects of potassium bromate (KBrO3), sodium bromate (NaBrO3), and potassium bromide (KBr) on the sexual reproduction of the rotifer Brachionus calyciflorus were studied by 2-d population growth, 4-d sexual reproduction, and 7-d resting egg production tests. The results showed that low concentrations of bromate promote 2-d and 4-d rotifer population growth, while high concentrations limit it. Bromate stress significantly affected parameters of rotifer sexual reproduction, including the ratio of mictic to amictic females, the mictic rate of rotifers, and the fertilization rate of mictic females. KBrO3 at 0.001, 0.01, 1, and 10 mg/L, NaBrO3 at 1 and 10 mg/L, and KBr at 100 and 200 mg/L significantly increased resting egg production, while KBrO3 at 100 and 200 mg/L, and NaBrO3 at 200 mg/L significantly decreased it. Resting egg production appears to provide a sensitive endpoint in evaluating the effect of bromate on rotifer sexual reproduction. [ABSTRACT FROM AUTHOR]

Bromide is universal in surface water influenced by salt tide and brackish water. It is harmless to human until transferring to bromate (a kind of disinfection byproducts) under certain conditions such as oxidation. Though both of them are not easily removed by conventional water treatment, nanofiltration seems to be an efficient way to solve the problems. In this study, the removal of bromate and bromide by nanofiltration membranes were systematically investigated, considering the system pressure (0.2–0.3–0.4 MPa), pH (5–7–9), ionic strength (0.005–0.05–0.1 mM), membrane type (NF270 and NF90), and the influences of organic matters (humic acid and sodium alginate). The membrane flux and the removal efficiency of anions were taken into consideration. According to the results, the membrane flux increased along with the system pressure, but slight influence on the removal of bromate and bromide was observed. Rising pH and ionic strength could not obviously deteriorate the flux. However, the removal of these anions was enhanced by increasing pH as well as decreasing ionic strength. Compared with humic acid, severer flux decline and deterioration of anion removal were achieved when sodium alginate was added in feed solution. Regardless of the operating conditions, bromate was more easily removed by nanofiltration membranes than bromide, which could result from different steric hindrance. Compared with NF270, NF90 can reject bromide and bromate more efficiently. The findings in the present study would contribute to the deep understanding of the factors affecting removal of bromate and bromide by nanofiltration and provides guidance about application of it. [ABSTRACT FROM AUTHOR]

Kinetic investigation of oxidation of tris(4,4'-dimethyl, 2,2'-bipyridine)iron(II) by bromate has been undertaken. The redox reaction between [Fe(dmbpy)3]2+ and bromate ion (BrO ) was monitored spectrophotometrically under the pseudo-first order condition i.e.[BrO ] ≫ [Fe(dmbpy)3]2+. Kinetic data revealed that the pseudo first order rate constant (kobs) is independent of the concentration of [Fe(dmbpy)3]2+. Though, when concentration of bromate ion is increased in reaction mixture at fixed pH, the rate also increases up to the saturation point at higher concentrations, indicating a precursor complex formation and an outer-sphere mechanism. The influence of accelerating [H+] and ionic strength on reaction rate were also investigated. The increasing values of the rate constant at low pH mention the involvement of protonated bromate species (HBrO3 and H2BrO ) in the rate-determining step. However, a rise in the value of the rate constant with increasing ionic strength implies the diprotonated species, H2BrO , as the reactive species. On the basis of these conclusions, we were able to postulate the appropriate mechanism and the rate law of this redox reaction. [ABSTRACT FROM AUTHOR]

Bromate is a disinfection byproduct (DBP) that forms during the ozonation of bromide-containing natural water, which may cause health risks to humans. In this review, we provide an overview of the mechanism of bromate formation, microbial communities and bioreactors that are responsible for bromate reduction. Bromate can be formed through two pathways of bromide oxidation by ozone or by ·OH, and it can be removed by biological approaches. Members belonging to phyla of Spirochaetes, Proteobacteria, Firmicutes, Actinobacteria, Clostridium, Deinococcus-Thermus and Bacteroidetes have been identified as capable of reducing bromate to bromide. Multiple configurations of biofilm bioreactors have been employed to cultivate microbial communities to perform bromate removal. The rapid development of multiomics has and will continue to accelerate the elucidation of the mechanisms involved in bromate and other DBP conversions, as well as the interaction patterns among different bacterial subdivisions in the bioremoval of DBPs. [ABSTRACT FROM AUTHOR]

In this study, poly(ethylene terephthalate) fibers grafted with 4-vinyl pyridine (PET-g-4VP) was synthesized with using a radical polymerization method and its removal capacity for bromate ions in the aqueous solution was explored. The synthesized graft copolymer was structurally characterized by scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR). The effect of some parameters such as pH, grafting rate, processing time, and ion concentration on bromate removal was examined with batch experiments. The sorptions of bromate onto the PET-g-4VP fibers were both verified with FTIR and X-ray fluorescence analysis (XRF) and the remaining amount of bromate after adsorption process was determined with an ion chromatography (Shimadzu). Moreover, kinetic and isotherm studies were also performed for adsorption of bromate with the grafted fibers. The point of zero charge (pHpzc) of the PET-g-4VP fibers was found to be 7.5 and the fibers removed maximum amount of bromate from aqueous solution at pH 3. Equilibrium time of adsorption was determined to be 75 min and the adsorption kinetic was found to be pseudo-second-order model. It was observed that the increase in the amount of grafted 4VP onto the PET fibers increased the bromate removal capacity of the fibers; however, when the grafting yield of 4VP was over 80%, the bromate removal ability of the fibers decreased. The maximum bromate removal capacity of the PET-g-4VP was determined to be 183 mg/g when the initial bromate amount was 800 mg/L, treatment time was 75 min, pH of the solution was 3, and 4VP grafting yield was 80%. When the initial bromate concentration was higher than 800 mg/L, the removal rate of the PET-g-4VP fibers was not changed. In addition, bromate ion adsorption data indicated compliance with the Freundlich isotherm. The adsorbent fibers obtained by this study may be promising candidates for the removal of bromate ions from the aqueous media. [ABSTRACT FROM AUTHOR]

The surface of a glassy carbon electrode modified with multi-walled carbon nanotubes (GCE/MWCNTs) was coated with a layer of phosphomolybdic acid (PMo12) and ionic liquid (n-dodecyl pyridinium hexafluorophosphate, [C12Py][PF6]). Cyclic voltammetry was performed to investigate the effect of [C12Py][PF6] on the electrochemical behavior of the prepared modified electrode, GCE/MWCNTs/[C12Py][PF6]-PMo12. The surface coverage and the rate constant of electron transfer for three redox pairs of the immobilized PMo12 were evaluated and compared with those obtained for GCE/MWCNTs/n-octyl pyridinium hexafluorophosphate ([C8Py][PF6])-PMo12 fabricated using [C8Py][PF6] in our previous study to find a correlation between the structure of ionic liquid and its effect. Thereafter, the electrocatalytic activity of GCE/MWCNTs/[C12Py][PF6]-PMo12 towards the reduction of nitrite, H2O2, iodate, bromate, chlorate, and periodate was investigated and the rate constant for the chemical reaction of each analyte with PMo12 at the electrode surface was calculated. The prepared electrode was then applied for the amperometric measurements of the mentioned analytes with the satisfactory electroanalytical characteristics. [ABSTRACT FROM AUTHOR]

A modified carbon paste electrode with Sn(II)-exchanged clinoptilolite nanoparticles (CNP-Sn(II)-CPE) showed voltammetric current (in cyclic voltammetry (CV)) for Sn(II)/Sn(IV) in sulfuric acid electrolyte (pH 2). The peak current was decreased when bromate was added to the solution. Hence, this decrease was used for indirect voltammetric determination of bromate. In designed experiments using response surface methodology (RSM) approach in square-wave voltammetry (SqW), strong acidic pH values (pH 1.8-2.5) caused an increased SqW voltammetric response, because such pH values bring sufficient Sn(II) as the electroactive species at the electrode surface via ion-exchange process. The optimal variables obtained are sulfuric acid as supporting electrolyte at pH 1.80, modifier% at 25, amplitude at 498.4 mV, step potential at 5.4 mV, and frequency at 25 Hz. The peak current of Sn(II)/Sn(IV) redox pair was inversely proportionate to the concentration of bromate. Hence, ΔI (difference in peak current in the absence and presence of bromate) was proportionally increased with increasing the concentration of bromate in the range of 5.00 to 100.00 μmol L−1 with a detection limit of 0.06 μmol L−1 bromate. The effect of some strong oxidizing agents was studied, and the results showed that when such agents are present at levels of 2.5 to 5 times greater than the bromate in the solution, they can cause a maximum error of 3% in the determination of bromate in sulfuric acid electrolyte at pH 2.5. [ABSTRACT FROM AUTHOR]

A series of flower-like Mg-Al-layered double hydroxides (FHMA) with four Mg/Al ratios were successfully prepared via a simple method which put the mixed solution of magnesium and aluminum in the mixed solution of water and ethylene glycol (EG). After calcination under 600 °C, the calcination products (CFHMA) were used to adsorb bromate anionic from aqueous solution. The FHMA, CFHMA, and reconstructed CFHMA were characterized by FT-IR, XRD spectra, TG/DTA, N2 adsorption-desorption isotherm, and SEM. It was found that FHMA had the flower-like morphology when Mg/Al ratio was 2 and 3. Moreover, FHMA lost the layered structures during calcination under 600 °C, but the disappeared structures were reconstructed after adsorption of bromate anionic, which was attributed to the “reformation effect” of FHMA with bromate as an interlayer anion. A series of adsorption studies were performed and the mechanism and reactivity of CFHMA were discussed including the effect of different kind of equilibration conditions, such as initial bromate anionic concentration, adsorbent dosage, contact time, initial solution pH, and co-existing anions. The results of adsorption displayed that the most suitable calcination temperature of FHMA is 600 °C, and the best ratio of Mg/Al is 2:1 to remove bromate anionic pollutant from water. The equilibrium adsorption data of CFHMA revealed a good compliance with the Langmuir model and the experimental data of CFHMA fitted well to the pseudo-second-order kinetic model. The calcination product of FHMA was a decent adsorbent of bromate anionic pollutant. [ABSTRACT FROM AUTHOR]

Remediation of contaminated groundwater by nanoscale zero-valent iron (nZVI) is widely becoming a leading environmentally friendly solution throughout the globe. Since a wide range of various nZVI-containing materials have been developed for effective remediation, it is necessary to determine an appropriate way to terminate the reactivity of any nZVI-containing material for a practical experimental procedure. In this study, bimetallic Ni/Fe-NPs were prepared to enhance overall reduction kinetics owing to the catalytic reactivity of nickel on the surface of nZVI. We have tested several chemical strategies in order to terminate nZVI reactivity without altering the concentration of volatile compounds in the solution. The strategies include surface passivation in alkaline conditions by addition of carbonate, and consumption of nZVI by a reaction competitor. Four halogenated chemicals, trichloroethylene, 1,1,1-trichloroethane, atrazine, and 4-chlorophenol, were selected and tested as model groundwater contaminants. Addition of carbonate to passivate the nZVI surface was not effective for trichloroethylene. Nitrate and then bromate were applied to competitively consume nZVI by their faster reduction kinetics. Bromate proved to be more effective than nitrate, subsequently terminating nZVI reactivity for all four of the tested halogenated compounds. Furthermore, the suggested termination method using bromate was successfully applied to obtain trichloroethylene reduction kinetics. Herein, we report the simple and effective method to terminate the reactivity of nZVI by addition of a reducing reactivity competitor. [ABSTRACT FROM AUTHOR]

Haloacetic acids (HAAs), which include chloroacetic acids, bromoacetic acids, and emerging iodoacetic acids, are toxic water disinfection byproducts. General screening methodology is lacking for simultaneously monitoring chloro-, bromo-, and iodoacetic acids. In this study, a rapid and sensitive high-performance ion chromatography-tandem mass spectrometry method for simultaneous determination of chloro-, bromo-, and iodo- acetic acids and related halogenated contaminants including bromate, bromide, iodate, and iodide was developed to directly analyze water samples after filtration, eliminating the need for preconcentration, and chemical derivatization. The resulting method was validated in both untreated and treated water matrices including tap water, bottled water, swimming pool water, and both source water and drinking water from a drinking water treatment facility to demonstrate application potential. Satisfactory accuracies and precisions were obtained for all types of tested samples. The detection limits of this newly developed method were lower or comparable with similar techniques without the need for extensive sample treatment requirement and it includes all HAAs and other halogenated compounds. This provides a powerful methodology to water facilities for routine water quality monitoring and related water research, especially for the emerging iodoacetic acids. [ABSTRACT FROM AUTHOR]

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 KBrO 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 O and Br in a heterogeneous gas-solid body system and in a homogeneous aqueous solution are compared. [ABSTRACT FROM AUTHOR]

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 NaSO 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 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. [ABSTRACT FROM AUTHOR]

Electromembrane extraction (EME) as a novel sample preparation technique was firstly applied for the purification and enrichment of bromate (BrO) in drinking water prior to capillary zone electrophoresis with capacitively coupled contactless conductivity detection (CZE-CD). BrO, as the primary disinfection by-product of ozonation, could be well separated with the major inorganic anions coexisting in water samples using a 300 mmol L acetic acid solution as the running buffer. Under the optimum conditions, the calibration curve showed good linearity ( r = 0.996), and the limit of detection was down to 0.12 ng mL with the enrichment factor at 267. The relative standard deviation (RSD) values for peak area and migration time at a spiked concentration of 10 ng mL of bromate were below 8.8 and 2.5 %, respectively. This proposed EME-CZE-CD method has been successfully applied to analyze bottled drinking water and tap water samples with recoveries in the range of 85~98 %, providing an alternative to the determination of bromate in drinking water. [ABSTRACT FROM AUTHOR]

We describe a simple method for non-titrimetric determination of oxidative species capable of oxidizing iodide to form free iodine. The combined action of iodine and excess iodide leads to the etching of gold nanoclusters stabilized with serum albumin. The extent of fluorescence quenching represents a direct signal for the amount of oxidative analytes. Compared to classical iodometry, tedious titration steps are not required and much smaller sample volumes are needed. This new assay provides a convenient means as demonstrated for the quantification of the oxidative analytes nitrite, bromate and periodate, with detection limits (at 3σ) of 11.7 μM, 1.7 μM, and 1.5 μM, respectively. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Proposed is the technique of spectrophotometric determination of sulfide in the range 0.05-1.50 mg/dm based on oxidation of it in the sulfate medium by the known excess of bromate followed by subsequent oxidation of N,N-diethylaniline in the presence of the excess of bromide and photometering at 226 nm of 4-bromo-N,N-dietylaniline being formed. The sulfide detection limit constitutes 0.03 mg/dm. Metrological characteristics of the technique were checked by way of determination of sulfide in waters in ballneotherapy (mud, silt, etc.). [ABSTRACT FROM AUTHOR]

Activated carbon was prepared from date pits via chemical activation with HPO. The effects of activating agent concentration and activation temperature on the yield and surface area were studied. The optimal activated carbon was prepared at 450 °C using 55 % HPO. The prepared activated carbon was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric-differential thermal analysis, and Brunauer, Emmett, and Teller (BET) surface area. The prepared date pit-based activated carbon (DAC) was used for the removal of bromate (BrO). The concentration of BrO was determined by ultra-performance liquid chromatography-mass tandem spectrometry (UPLC-MS/MS). The experimental equilibrium data for BrO adsorption onto DAC was well fitted to the Langmuir isotherm model and showed maximum monolayer adsorption capacity of 25.64 mg g. The adsorption kinetics of BrO adsorption was very well represented by the pseudo-first-order equation. The analytical application of DAC for the analysis of real water samples was studied with very promising results. [ABSTRACT FROM AUTHOR]

By introducing a bridging ligand of 5-methylisophthalic acid (shortened as 5-mip) into the tetrahedral Zn-ε-Keggin system, a new 2D network of [TBA][HPMoMoOZn][CH(COO)] ( 1) was synthesized under hydrothermal condition. It was characterized by FT-IR, BET, TGA/DSC-MASS analysis, powder X-ray diffraction and single-crystal X-ray diffraction, respectively. Besides, compound 1 shows remarkable electrocatalytic activity towards bromate reduction. [ABSTRACT FROM AUTHOR]

The ozonation involved in drinking water treatment raises issues of water quality security when the raw water contains bromide (Br). Br ions may be converted to bromate (BrO) during ozonation and some brominated disinfection by-products (Br-DBPs) in the following chlorination. In this study, the effects of ozone (O) dosage, contact time, pH, and Br and ammonia (NH-N) concentrations on the formation of BrO and Br-DBPs have been investigated. The results show that decreasing the initial Br concentration is an effective means of controlling the formation of BrO. When the concentration of Br was lower than 100 μg/L, by keeping the ratio of O dosage to dissolved organic carbon (DOC) concentration at less than 1, BrO production was effectively suppressed. The concentration of BrO steadily increased with increasing O dosage at high Br concentration (>900 μg/L). Additionally, a longer ozonation time increased the concentrations of BrO and total organic bromine (TOBr), while it had less impact on the formation potentials of brominated trihalomethanes (Br-THMFP) and haloacetic acids (Br-HAAFP). Higher pH value and the presence of ammonia may lead to an increase in the formation potential of BrO and Br-DBPs. [ABSTRACT FROM AUTHOR]

A highly accurate and reproducible micellar sensitized kinetic method was proposed for determination of V(VI). The method is based on its catalytic effect on the oxidation of Coomassie brilliant blue R 250 (CBB) by bromate at pH 2.0. The reaction was monitored spectrophotometrically by measuring absorbance change with a fixed-time method of 5 min at 594 and 552 nm with and without surfactant. The variables influencing the calibration sensitivity were extensively investigated, and the optimal conditions were established. The linear calibration range was 10-1,600 μg·L with a relative SD ranging from 0.35 % to 3.35 % (for five replicate measurements of 75, 500, 1,000, and 1,500 μg·L) and a detection limit of 3.8 μg·L. The selectivity was also investigated, and greatly enhanced by suitable masking agents. The method was successfully applied to the analysis of V(IV) in presence of excess V(V) up to 25 fold in environmental waters with the recoveries of 100.0 %-102.8 % for V(IV) and 95.7 %-99.7 % for total V. Its accuracy was validated by analysis of certified reference material via the present kinetic method and standard flame atomic absorption spectrometric method after extractive preconcentration with good agreement between certified and found values. [ABSTRACT FROM AUTHOR]

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 FeO nanoparticles (Ph-SiO@FeO), 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 range with reasonable linearity ( r > 0.998); and the limit of detection is 0.5 ng mL. 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. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Orthogonal method was adopted to optimize the preozonation process and to minimize the bromate formation. Factors such as contact time, pH and ammonia concentration were investigated by orthogonal experiments to understand the interaction of various operation conditions on the formation of bromate and other disinfection byproducts(DBPs). Results showed that pH had the most significant influence on the minimization of bromate formation. The factors influencing the formation of bromate were in order of pH > contact time > ammonia concentration. For the formation of trihalomethanes(THMs) and haloacetic acids(HAAs), however, contact time significantly influenced their formation potential. In the practical preozonation process of waterworks, it is appropriate to set preozonation contact time to be 20 min. In order to minimize the formation of bromate, pH value of the raw water should be adjusted to 6. 0, and a certain concentration of ammonia could be added into the water to strengthen the minimization effect when the concentration of bromide in the raw water is higher than that in the experimental water. [ABSTRACT FROM AUTHOR]

In this paper, a simple and sensitive spectrophotometric method for the determination of nanomolar level of bromate, based on the catalytic effect of silver nanoparticles on the oxidation of acid red 14 by potassium bromate, is described. The reaction rate was monitored spectrophotometrically by measuring the decrease in absorbance of acid red 14 at 516 nm. The detection limit of the method was 8 ng/mL, and the linear range was between 15 and 130 ng/mL. The effects of acidity, concentration of reactants and reaction time, and external ions were also discussed. The optimum reaction conditions were fixed, and some kinetic parameters determined. The relative standard deviation for the determination of bromate at the concentration of 50 ng/mL was calculated to be 0.996 % ( n = 10). The method has been successfully applied to the determination of bromate in flours and bottled waters. [ABSTRACT FROM AUTHOR]

Bromate (BrO), a by-product of ozonation of drinking water, induces nephrotoxicity in male rats at much lower doses than in female rats. This difference appears to be related to the development of α-2-globulin nephropathy in males. To determine sex-dependent changes in mRNA and protein expression in the renal cortex attributable to α-2-globulin nephropathy, we performed microarray and immunohistochemical analyses in proximal renal tubules of male and female F344 rats treated with KBrO for 28 days. Particular attention was paid to molecular biomarkers of renal tubular injury. Microarray analysis of male and female rats treated with BrO at low doses (125 mg/L KBrO) displayed marked sex-dependent changes in renal gene expression. The greatest differences were seen in genes encoding for cellular differentiation, apoptosis, ion transport, and cell proliferation. Differences by sex were especially prominent for the cell cycle checkpoint gene p21, the renal injury protein Kim-1, and the kidney injury and cancer biomarker protein osteopontin. Dose-related nephrotoxicity, assessed by hematoxylin and eosin staining, was greater in males compared to female rats, as was cellular proliferation, assessed by bromodeoxyuridine staining. The fraction of proximal renal cells with elevated 8-oxodeoxyguanosine (8-OH-dG) was only increased at the high dose and did not differ by sex. Dose-dependent increases in the expression of osteopontin were detected immunohistochemically only in male rats and were localized in proximal tubule cells. Similarly, BrO treatment increased clusterin and Kim-1 staining in the proximal tubules; however, staining for these proteins did not differ appreciably between males and females. These data demonstrate both qualitative and quantitative differences in the response of male versus female kidneys to BrO-treatment. These sex-dependent effects likely contribute to renal carcinogenesis of BrO in the male rat. [ABSTRACT FROM AUTHOR]

This study focuses on the chemical analysis of the available brands of domestic bottled water in Riyadh City, Saudi Arabia. The distribution of the chemical constituents (major, minor, and trace elements) is determined and compared with the chemical content labeled on the bottles and with drinking water standards of Saudi Arabian, World Health Organization, and U.S. Environmental Protection Agency. The obtained results indicated that except for fluoride and bromate, the concentrations of dissolved salts, soluble cations and anions, nitrate, and trace elements of most bottled waters on sale were within the permissible limits set by standards used. On the other hand, the comparison between determined and reported label values recorded a substantial variation in some parameter values. Results indicated that more than 18 % of the sampled bottled waters exceeded the allowable limits for drinking water. Generated Piper diagrams revealed that the majority of investigated waters were sodium chloride-sulfate type; however, the hydrochemical modeling indicated that all water samples were undersaturated for anhydrite, gypsum, and halite. [ABSTRACT FROM AUTHOR]

A sensitive chromatographic method was developed for the determination of trace level bromate in food and drinking water. The method was based on a poly (glycidyl methacrylate-co-ethylene dimethacrylate) monolithic column, which was prepared by in situ polymerization and further modified with quaternary amine groups. Morphology of the stationary phases was studied by scanning electron microscopy. Permeability and mechanical stability of the column were both excellent. Bromate was detected after post-column reaction with potassium iodide at 352 nm. The parameters affecting the detection limit of bromate were studied in detail. Under the optimum conditions, the detection limit for bromate was 1.5 μg/L. This method showed good linearity over the concentration range 5.0-30 μg/L, short analysis time (8.5 min), and satisfactory relative standard deviation of the replicate analysis ( n = 6, 0.043 %). [ABSTRACT FROM AUTHOR]

We have developed procedures for the spectrophotometric determination of ClO, BrO, and IO in waters of different origin. The procedures are based on the oxidation of N,N-diethylaniline in acidic media and their detection limits (by 3 s criterion) are 0.04, 0.18, and 0.53 μg/mL, respectively. The calibration curves are linear in the concentration ranges 0.1-2.0, 0.4-12.5, and 1.6-40 μg/mL, respectively. The procedures provide simple and rapid determination of these analytes. [ABSTRACT FROM AUTHOR]

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. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Bromide electrolysis was carried out on laboratory-scale cells in the range of 1-1,005 mg [Br] dm using boron-doped diamond (BDD) anodes. These studies were part of fundamental research activities on drinking water electrolysis for disinfection. Synthetic water systems were mostly used in the experiments, which varied the temperature between 5 and 30 °C, the current density between 50 and 700 A m, and the rotation rate of the rotating anode between 100 and 500 rpm (laminar regime). Hypobromite and bromate were found as by-products, as expected. Bromite was not detected. Higher bromate levels were formed at higher current density, but no clear relationship was observed between bromate concentration and the rotation rate or temperatures between 5 and 30 °C. Bromate yields higher than 90% were found at higher charge passed. Perbromate was found as a new potential synthesis or disinfection by-product (DBP), but no perbromate was detected at the lowest bromide concentrations and under drinking water conditions. The perbromate yield was about 1%, and somewhat lower when bromate was used as a starting material instead of bromide. At a temperature of 5 °C more perbromate was detected compared with experiments at 20°. Approximately 20 times more perchlorate was formed compared with perbromate formation in the presence of chloride ions of equimolar concentration. State of mechanistic considerations is presented and a mechanism for perbromate formation is proposed. The reaction from bromate to perbromate was found to be limited that is in contrast to the earlier studied chlorate-to-perchlorate conversion. In the measured concentration range, reduction processes at the mixed oxide cathode showed a much higher impact on the resulting concentration for perbromate than for bromate. [ABSTRACT FROM AUTHOR]

The kinetics of the oxidation of neutral red by bromate was investigated in the presence of cationic surfactant (Ndodecylpyridinium chloride) and strongly acidic media over the temperature range 22-35 °C. The kinetic studies were carried out as a function of different variables like concentration and temperature. The described reaction rate is greatly catalyzed by the presence of trace amount of Fe(II) ions and followed by pseudo-third-order kinetics with respect to dye concentration. A possible mechanism for the catalyzed reaction is offered which is found to be coincidentally congruent with experimental findings. The derived rate equation is in good agreement with the experimental observations. Thermodynamic parameters were also evaluated. [ABSTRACT FROM AUTHOR]

In this paper we report a simple and effective on-line sample-stacking method in capillary electrophoresis for analysis of bromate ion. The detection limit is 10.9 ng mL−1. Direct injection is performed after a simple extraction procedure. It is possible to detect 2.18 mg kg−1 bromate ion in flour by use of this technique. [ABSTRACT FROM AUTHOR]

A kinetic method has been developed for the spectrophotometric determination of subnanogram per milliliter levels of vanadium in the presence of large amounts of sodium chloride. The method is based on the catalytic effect of vanadium(V) on the oxidative coupling of N, N-diphenylhydrazine with chromotropic acid in the presence of bromate. In this reaction, chloride enhanced the catalysis of vanadium(V). Vanadium(IV) could be also determined because of its oxidation by bromate. By measuring the change in absorbance of the dye produced at a fixed time, vanadium(IV) and vanadium(V) in the range of 0.01–0.2 ng mL−1 could be determined. The relative standard deviation was 2.0% for ten determinations of 0.1 ng mL−1 vanadium(V). Interferences from diverse ions could be suppressed by the use of ethylenediamine- N, N, N′, N′-tetrakis(methylenephosphonic acid) as a masking agent. The method was successfully applied to the determination of vanadium(IV) and vanadium(V) in chloride-rich samples. [ABSTRACT FROM AUTHOR]

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The column-switching technique has been widely used to determine trace level ions in the presence of high concentration matrix. A novel simplified column-switching method is proposed where bromate (as a model compound) was determined using this technique. The switching time window was confirmed by the retention time of determined ions. This technique can completely carry out the same function as the other column-switching technique do, but only one extra ten-way injection valve coupled to ion chromatograph was used. By using column-switching technique, it is possible to determine 0.2 µg L−1 bromate in the presence of 100 mg L−1 chloride by direct injection of 2000 µL without any pretreatment and the relative standard deviation (RSD) of the peak height for the eleven successive injections of 0.2 µg L−1 bromate solution is 23.1%. The detection limit for bromate is 0.09 µg L−1, which showed the method was very sensitive. The technique has been applied to the determination of bromate in drinking water, and the spike recovery is in the range of 96–104%. [ABSTRACT FROM AUTHOR]

Based on selective sorption of bromide, bromoacetic acids (BAA) and bromomethanes on solid-phase extraction (SPE) cartridges, a sensitive and convenient method was developed for the determination of bromate in waters by inductively coupled plasma mass spectrometry (ICP–MS). Dionex OnGuard Ag and reversed-phase (RP) cartridges were tested for retention characteristics for bromide, BAA and bromomethanes. When a sample acidified with nitric acid was passed through an RP cartridge, BAA and bromomethanes were retained, afterwards bromide was absorbed as a precipitate of silver bromide and bromate was unretained when the nearly neutral sample passed a combination of Ag and H cartridges. After SPE pretreatment the recovery of bromate was 96–106%, and bromide remaining in the aqueous phase was found to be less than 0.06 μg L-1 when the original bromide concentrations were less than 5 mg L-1. Effectiveness of stacked Ag and H cartridges in removing bromide from chloride-containing samples was also examined. Common cations and other anions did not interfere with bromate determination. The detection limit for bromate is 57 ng L-1. This method has been applied to analyse waters from various sources, and the recovery of the spiked bromate was in the range of 92–107%. [ABSTRACT FROM AUTHOR]

Three different methods developed for the determination of salbutamol sulfate (SBS), in pure drug form and in dosage forms, are discussed. The methods are based on the oxidation–bromination reaction of the drug by bromine generated in-situ by the interaction of bromate with bromide in acid medium. In titrimetry the drug is titrated directly with bromate in the presence of a large excess of bromide and in sulfuric acid medium using methyl red as indicator. Spectrophotometry is based on addition of a measured excess of bromate–bromide mixture to the sample solution in sulfuric acid medium followed by the estimation of surplus bromine by reacting it with a definite amount of methyl orange dye and measuring the absorbance at 510 nm. The amount of bromate reacting corresponds to the sample content. The kinetic method depends on the linear relationship between the concentration of the drug and time for oxidation and bromination as indicated by the bleaching of the methyl orange acid colour by the bromine generated in situ. Titrimetry is applicable in the 2–20 mg range. In spectrophotometry, Beer's law is obeyed in the 0.5–5.0 μg mL-1 range whereas concentrations in the 5.0–25.0 μg mL-1 range can be determined by the kinetic method. The effect of common excipients and additives in tablets is discussed. The procedures have been successfully applied to dosage forms; the results agree well with those obtained by use of a reference method. The methods can be used to determine SBS at mg or μg levels. [ABSTRACT FROM AUTHOR]

A polymer electrolyte fuel cell with Pt grid electrodes employing acidic lithium bromate as the oxidant and alkaline sodium borohydride as the reducer is demonstrated. Such system provides simultaneously high energy (over 1000 A h/L and 660 A h/kg in the tanks) and high power (0.5 W/cm at 60°C) densities on discharge. A regenerative fuel cell cycle employing hydrogen as the reducer is also discussed. [ABSTRACT FROM AUTHOR]

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