Bromine Content Research Articles

Genotoxicity and endocrine disruption potential of haloacetic acids in human placental and lung cells

Chlorination of water results in the formation of haloacetic acids (HAAs) as major disinfection byproducts (DBPs). Previous studies have reported some HAAs species to act as cytotoxic, genotoxic, and carcinogenic. This work aimed at further exploring the toxicity potential of the most investigated HAAs (chloroacetic (CAA), bromoacetic (BAA), iodoacetic (IAA) acid) and HAAs species with high content of bromine (tribromoacetic acid (TBAA)), and iodine in their structures (chloroiodoacetic (CIAA) and diiodoacetic acid (DIAA)) to human cells. Novel knowledge was generated regarding cytotoxicity, oxidative stress, endocrine disrupting potential, and genotoxicity of these HAAs by using human placental and lung cells as in vitro models, not previously used for DBP assessment. IAA showed the highest cytotoxicity (EC50: 7.5 μM) and ability to generate ROS (up to 3-fold) in placental cells, followed by BAA (EC50: 20–25 μM and 2.1-fold). TBAA, CAA, DIAA, and CIAA showed no significant cytotoxicity (EC50 > 250 μM). All tested HAAs decreased the expression of the steroidogenic gene hsd17b1 up to 40 % in placental cells, and IAA and BAA (0.01–1 μM) slightly inhibited the aromatase activity. HAAs also induced the formation of micronuclei in A549 lung cells after 48 h of exposure. IAA and BAA showed a non-significant increase in micronuclei formation at low concentrations (1 μM), while BAA, CAA, CIAA and TBAA were genotoxic at exposure concentrations above 10 μM (100 μM in the case of DIAA). These results point to genotoxic and endocrine disruption effects associated with HAA exposure at low concentrations (0.01–1 μM), and the usefulness of the selected bioassays to provide fast and sensitive responses to HAA exposure, particularly in terms of genotoxicity and endocrine disruption effects. Further studies are needed to define thresholds that better protect public health.

Influence of high-bromine poultry products on clinical-biochemical blood parameters of white rats

Bromine content in fodder and water for laying chickens in Ukraine gradually increasing, thereby accumulating in the poultry production (eggs and meat): according to the data, intake of bromine with chicken eggs in 2020 has almost doubled, compared with 2016. Taking into account the ability of bromine to accumulate and the scales of consumption of poultry products, it is relevant to study the effects of high bromine concentration on the level of thyroid hormones and clinical-biochemical parameters of blood of white rats. At the laboratory of Toxicological Monitoring of the National Scientific Center the Institute of Experimental and Clinical Veterinary Medicine and the Department of Experimental Pharmacology and Toxicology of the State Institution V.Y. Danylevskyi Institute of Problems of Endocrine Pathology of the National Academy of Medical Sciences of Ukraine, we carried out studies on white outbred male rats (n = 144). The diet of experimental groups was supplemented with eggs and meat containing high bromine concentration. We determined increase in the coefficients of liver weight and decrease in the coefficients of lung weight in the experimental rats. Moreover, we determined changes in the biochemical blood profile, in particular: after egg consumption, there occurred 20.0–22.0% decrease in the enzymatic activity of alanine aminotransferase, 23.0–48.4% in the activity of aspartate aminotransferase, and on average 21.3% decrease in alkaline phosphatase, compared with the control; after meat consumption, the level of total proteins decreased by 8.6%, glucose by 12.2–14.5%, also there were 13.8–18.5% decrease in the activity of alanine aminotransferase and 12.1–83.0% increase in the activity of aspartate aminotransferase on the 28th day, and 23.2–35.3% decrease in the activity of alkaline phosphatase. After the intake of both poultry products, the blood serum of animals was observed to have decrease in the level of overall thyroxine and overall triiodothyronine (1.3 times on average, depending on the period of study). The results of the studies can help in prediction and timely alleviation of the negative impact of poultry products with high bromine content on the human organism.

Evaluation of Some Toxic Trace Elements in Crocus Sativus L. and Soil Using Neutron Activation Analysis Technique

Neutron activation analysis was used in this research to measure the concentrations of aluminum (Al), bromine (Br), chlorine (Cl), mercury (Hg), arsenic (As), and thorium (Th) in soil and saffron plants as well as their contamination, enrichment, and translocation rates. The edible part of the saffron showed a higher Hg concentration than the WHO/FAO-permitted level in the urban area. The soil was not intoxicated and contaminated by Al, As, and Th except in the urban areas, which were slightly polluted by As. The calculated contamination degree and pollution load index indicated that the soil was almost uncontaminated. The enrichment factors (EF) showed minimal enrichment levels of Al and Th and low As contamination, which may still increase due to human activities in the environment. The tested elements’ translocation abilities were also evaluated by the paired t-test statistical method and indexes of translocation, and it was found that Al, As, and Th can quickly relocate into different soil depths. Saffron was also evaluated as a very poor absorber of the elements studied. While Cl and Th can easily move from the saffron’s corm to its aerial parts, Al and Hg merely translocate from the corm to the petal. It was also found that Al, Cl, and Th can move between the petals and the thread.

Compatibilized PC/ABS blends from solvent recycled PC and ABS polymers from electronic equipment waste

This study encompasses the development of high-performance PC/ABS blends utilizing recycled PC (r-PC) and recycled ABS (r-ABS) polymers from waste electric and electronic equipment (WEEE) fractions heavily contaminated by flame retardants (FRs). Upgrading of mechanical properties was facilitated by addition of virgin ABS and additives. In total three different WEEE fractions -containing high concentrations of bromine, chloride and phosphorous were purified from polymers other than PC and decontaminated from halogenated contaminants by dissolution-precipitation CreaSolv® Process. In two studied cases the WEEE fractions were optically pre-sorted for PC before purification and decontamination. Gas chromatography (GC-ECD) and X-ray fluorescence (XRF) analyses were performed to validate efficient removal of contaminants from r-PC.The targeted mechanical properties of polymers to upgrade are notched impact strength and elastic moduli. Upgrading was achieved by using the suitable compatibilizers, and, optionally by a chain extender. First, small-scale laboratory screening test series were conducted for three compatibilizers and different ABS polymers based on micro-compounding experiments. Upscaling test series based on the pre-screening data was then organized on a conventional bench scale twin-screw extruder.SEM microstructural characterizations of the blend morphology and fractured surfaces are done to correlate structure to the mechanical properties.Dynamic mechanical analysis (DMA) and Rheological Dynamic Analysis (RDA) and Gel permeation chromatography (GPC) provided some insight to the chain branching and molecular weight distribution of r-PC, respectively. Moreover, melt rheology and solid-state mechanical properties of the compatibilized r-PC/ABS blend were thoroughly investigated.Addition of virgin ABS polymer and a suitable compatibilizer enhance the properties of the recycled PC/ABS 60/40 blends towards virgin-like, allowing easily >55% r-PC content, or in favourable cases much higher than 75% recycled polymer content when applying significant concentration of recycled ABS from CreaSolv® together with some virgin ABS.

Bromine Content Differentiates between Construction and Packaging Foams as Sources of Plastic and Microplastic Pollution

Plastic foams are used to make food packaging, consumer product protective packaging, and building insulation materials–each of which are reported in the environment. This study investigated the contributions of construction and packaging applications to foam plastic litter using visual characteristics and the presence of bromine (Br) from flame retardants as an identifying signature. A foam source library of 86 examples that included building materials and packaging demonstrated that 96% of building materials contained Br while only 5% of foam packaging did, as measured by hand-held X-ray fluorescence (XRF) spectrometry. The XRF enabled the detection of Br in particles down to 1 mm in size, enabling both macro- and microplastic foams to be quantitatively assessed for the relative contributions of construction-based activities and packaging sources to the abundance of foam found on Toronto-area beaches, in tributaries, and in Lake Ontario waters adjacent to Toronto. Beach and surface water surveys revealed 58% and 51% of samples, respectively, contained concentrations of Br consistent with construction foams. This significant proportion highlights a need for greater attention toward the management of construction foam waste, for example, developing and implementing best management practices at active sites to prevent foam litter from entering the environment.

Removal of Bromine from Polymer Blends with a Composition Simulating That Found in Waste Electric and Electronic Equipment through a Facile and Environmentally Friendly Method.

The increasing volume of plastics from waste electric and electronic equipment (WEEE) nowadays is of major concern since the various toxic compounds that are formed during their handling enhance the difficulties in recycling them. To overcome these problems, this work examines solvent extraction as a pretreatment method, prior to thermochemical recycling by pyrolysis. The aim is to remove bromine from some polymeric blends, with a composition that simulates WEEE, in the presence of tetrabromobisphenol A (TBBPA). Various solvents-isopropanol, ethanol and butanol-as well as several extraction times, were investigated in order to find the optimal choice. Before and after the pretreatment, blends were analysed by X-ray fluorescence (XRF) to estimate the total bromine content. Blends were pyrolyzed before and after the soxhlet extraction in order to evaluate the derived products. FTIR measurements of the polymeric blends before and after the soxhlet extraction showed that their structure was maintained. From the results obtained, it was indicated that the reduction of bromine was achieved in all cases tested and it was ~34% for blend I and ~46% and 42% for blend II when applying a 6 h soxhlet with isopropanol and ethanol, respectively. When using butanol bromine was completely eliminated, since the reduction reached almost 100%. The latter finding is of great importance, since the complete removal of bromine enables the recycling of pure plastics. Therefore, the main contribution of this work to the advancement of knowledge lies in the use of a solvent (i.e., butanol) which is environmentally friendly and with a high dissolving capacity in brominated compounds, which can be used in a pretreatment stage of plastic wastes before it is recycled by pyrolysis.

Interference-free electron probe micro-analysis of bromine in halogen-bearing minerals and glasses: high-resolution measurements and quantitative elemental mapping.

Previous attempts to measure Br in minerals and glasses via electron probe micro-analyzers (EPMA) required interference corrections via calibration curves in order to account for Al X-ray overlap with the Br Lβ X-ray signal. We present a new approach for using EPMA for Br quantification in halogen-bearing minerals and glasses by measuring the interference-free Br Kα X-ray signal (11.909 keV), using a lithium fluoride (LiF) diffracting crystal. A set of Br-doped glasses as well as Cl- and Br-bearing scapolite-group minerals that were previously characterized by SIMS, INAA, LAICPMS, EPMA, and the Noble Gas Method, is compared to new EPMA measurements. Bromine concentrations in the tested samples range from ∼10 to ∼3500 μg g-1 and our study shows that estimated limit of quantifications of ∼120 μg g-1 Br and ∼15 μg g-1 of Cl can be reached. In addition, we show that this new approach permits the acquisition of quantitative Cl and Br maps in minerals, which provide high-resolution insights into crustal fluid properties.

Changes in toxicity and adsorbable organic bromine concentrations in ozonated reclaimed water irradiated with sunlight

Disinfecting reclaimed water for safe reuse can produce toxic disinfection by-products such as adsorbable organic bromine (AOBr). Irradiating stored reclaimed water with sunlight is a “green” and free method for eliminating some toxic disinfection by-products, but the effects of irradiation with sunlight on ozonated reclaimed water containing bromide are not well understood. In this study, AOBr was found at concentrations of 171–180 (µg Br)/L in ozonated reclaimed water containing bromide at a concentration of 2 (mg Br)/L and dissolved organic carbon at a concentration of ∼5 (mg C)/L. Irradiation with sunlight degraded 53–74% of the AOBr in two reclaimed water samples in 8 h, and the pseudo-first-order rate constants (k) were 0.09–0.17 h−1. The concentration of tribromomethane, a typical Br-containing disinfection by-product, was decreased by >96% by irradiation for 8 h (k = 0.42–0.47 h−1). Irradiation with sunlight decreased the toxicity of ozonated reclaimed water to Chinese hamster ovary cells. Irradiation with sunlight decreased the degree of intracellular oxidative stress and oxidative damage caused by ozonated reclaimed water. Irradiation with sunlight for 8 h decreased cytotoxicity of the ozonated reclaimed water samples by 79% and 65%. The change in AOBr concentration correlated with the change in toxicity (R2=0.69, p<0.05). The relationships between sunlight wavelength and decreases in the AOBr concentration and toxicity were assessed, and it was found that UV in sunlight was predominantly responsible for decreasing the AOBr concentration and toxicity by reclaimed water. During irradiation for 8 h, UV was responsible for 65%–66% of the decrease in the AOBr concentration and 65–79% of the decrease in reclaimed water induced cytotoxicity. Irradiation with sunlight is a promising method for degrading AOBr and detoxifying ozonated reclaimed water during storage to allow the water to be reused.

An Investigation on Bromine Content Assessment in e-Waste Plastics by Short Wave Infrared (SWIR) Spectroscopy

This paper reported a study based on the application of SWIR (shortwave infrared) spectroscopy to assess the presence of brominated flame retardants (BFRs) in plastic scraps coming from an e-waste stream composed by CRT (i.e., cathode-ray tube) monitors and televisions. An X-ray fluorescence (XRF) analysis was performed on plastic scraps to determine the presence and content of bromine (Br). The presence in plastic waste-flow streams, fed to or resulting from a recycling process, of individuals characterized by high concentrations of Br does not allow their use as secondary raw materials, imposing the need for an ad hoc separation processes. Chemometric methods were adopted for setting up models able to discriminate Br content. In more detail, principal component analysis (PCA) was used as an exploratory tool, while partial least squares (PLS) and locally weighted regression based on PLS regressions (LWRPLS) were used as multivariate regression models to test the ability of the spectra to predict Br content. The LWRPLS, showing an Rp2 of about 0.9, demonstrates the ability of this algorithm to establish a good correlation between the spectral signatures of plastic scraps and their Br content.

Separation of bromine and hydrocarbons from polymeric constituents in e-waste through thermal treatment with calcium hydroxide

Complete and deep removal of bromine from polymeric constituents in waste printed circuit boards (WPCBs) signifies the prime aim of the commonly deployed catalytic/pyrolytic approach in the treatment of e-waste. To attain this aim, a wide array of debromination agents were utilized with varying degree of effectiveness, scalability, and economic viability. Through the use of a multitude of techniques (flow reactor experiments, chemical analysis, surface characterization, and molecular simulation), this work presents conclusive evidence that co-pyrolysis of tetrabromobisphenol A (TBBA; as a model compound for the bromine content in WPCBs) with calcium hydroxide (Ca(OH)2) results in a complete fixation of the bromine content and produces bromine-free pyrolysis oil. For instance, measurements by IC and FTIR (gas sampling cell) confirms the disappearance of HBr from the gaseous stream during co-pyrolysis of a TBBA (1):Ca(OH)2 (2) mixture between 200 and 500 °C. Likewise, no brominated compounds could be detected from the analysis of the condensate and gas fractions. As the collected oil is dominated by n-alkanes, it is concluded that Ca(OH)2 displays both cracking and debromination capacity. DFT calculations maps out reaction pathways for the transformation of Ca(OH)2 into CaBr2 via the dissociative addition of HBr molecules. Formed CaBr2 could open a venue for a complete recovery of bromine in the thermal treatment of e-waste. Outcomes reported herein shall be instrumental in the design and operation of an effective chemical recycling facility for the ever-increasing loads of e-waste.

Implementation and evaluation of the GEOS-Chem chemistry module version 13.1.2 within the Community Earth System Model v2.1

Abstract. We implement the GEOS-Chem chemistry module as a chemical mechanism in version 2 of the Community Earth System Model (CESM). Our implementation allows the state-of-the-science GEOS-Chem chemistry module to be used with identical emissions, meteorology, and climate feedbacks as the CAM-chem chemistry module within CESM. We use coupling interfaces to allow GEOS-Chem to operate almost unchanged within CESM. Aerosols are converted at each time step between the GEOS-Chem bulk representation and the size-resolved representation of CESM's Modal Aerosol Model (MAM4). Land-type information needed for dry-deposition calculations in GEOS-Chem is communicated through a coupler, allowing online land–atmosphere interactions. Wet scavenging in GEOS-Chem is replaced with the Neu and Prather scheme, and a common emissions approach is developed for both CAM-chem and GEOS-Chem in CESM. We compare how GEOS-Chem embedded in CESM (C-GC) compares to the existing CAM-chem chemistry option (C-CC) when used to simulate atmospheric chemistry in 2016, with identical meteorology and emissions. We compare the atmospheric composition and deposition tendencies between the two simulations and evaluate the residual differences between C-GC and its use as a stand-alone chemistry transport model in the GEOS-Chem High Performance configuration (S-GC). We find that stratospheric ozone agrees well between the three models, with differences of less than 10 % in the core of the ozone layer, but that ozone in the troposphere is generally lower in C-GC than in either C-CC or S-GC. This is likely due to greater tropospheric concentrations of bromine, although other factors such as water vapor may contribute to lesser or greater extents depending on the region. This difference in tropospheric ozone is not uniform, with tropospheric ozone in C-GC being 30 % lower in the Southern Hemisphere when compared with S-GC but within 10 % in the Northern Hemisphere. This suggests differences in the effects of anthropogenic emissions. Aerosol concentrations in C-GC agree with those in S-GC at low altitudes in the tropics but are over 100 % greater in the upper troposphere due to differences in the representation of convective scavenging. We also find that water vapor concentrations vary substantially between the stand-alone and CESM-implemented version of GEOS-Chem, as the simulated hydrological cycle in CESM diverges from that represented in the source NASA Modern-Era Retrospective analysis for Research and Applications (Version 2; MERRA-2) reanalysis meteorology which is used directly in the GEOS-Chem chemistry transport model (CTM). Our implementation of GEOS-Chem as a chemistry option in CESM (including full chemistry–climate feedback) is publicly available and is being considered for inclusion in the CESM main code repository. This work is a significant step in the MUlti-Scale Infrastructure for Chemistry and Aerosols (MUSICA) project, enabling two communities of atmospheric researchers (CESM and GEOS-Chem) to share expertise through a common modeling framework, thereby accelerating progress in atmospheric science.

Thermochemical conversion of African balsam leaves‐cow dung hybrid wastes into biochar

AbstractAfrican balsam (Daniella oliveri) leaves and cow dung are waste materials that are commonly accessible in Africa and can be used to produce biochar by simultaneous thermochemical processing. In this study, biochar was produced in a retort‐heated, non‐electrically powered, top‐lit updraft reactor using the biomass fuel‐powered thermochemical conversion of dried cow dung and African balsam leaves at an average temperature of 320 °C. The biochar was characterized using Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and Brunauer–Emmett–Teller (BET) analyses. After carbonization for 100 min, biochar was obtained from processed mixed leaves/cow dung with a yield of 70%. Fourier transform infrared analysis showed the presence of alkene, hydroxyl, alkyne, alkane, and sulfur‐containing functional groups. Scanning electron micrographs showed that the biochar's surface was made up of fibrillated particles with very few pores. The biochar was observed to have a surface area of 328.199 m2/g with a higher pore volume and lower pore size than biochar produced from cow dung alone. Energy dispersive spectroscopy showed that the biochar is mostly made up of carbon (67%), and that the introduction of the leaves into the biochar feedstock increased its carbon, silicon, potassium, and bromine content. Differential thermal analysis/thermogravimetric analyses revealed the biochar to be thermally stable. The findings of this study are helpful for attempts to manage solid wastes (African balsam leaves and cow dung), reduce environmental pollution, and produce biochar whose properties are adequate for it to be used as a soil additive. © 2022 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

The effect of cotton stalk concentration on morphology and fixing bromine content in char while on co-pyrolysis with non-metal fractions of PCB

The effect of cotton stalk concentration on morphology and fixing bromine content in char while on co-pyrolysis with non-metal fractions of PCB

Effect of bromide doping on the phase stability and shelf life of the triple cation mixed halide perovskite single-crystals

• Growth of triple cation mixed halide perovskite (TCMHP) single crystals. • Suppression of yellow phase in TCMHP single crystals by the addition of bromine. • Optimization of bromine content in TCMHP single crystal for long term stability. The spontaneous phase transition occurs in the Formamidinium lead iodide (FAPbI 3 ) perovskite from photoactive black α-FAPbI 3 to photo-inactive yellow δ- FAPbI 3 poses a severe challenge to the long-term stability of this otherwise highly attractive photoactive material. The low-energy rotation of the formamidinium (FA) cation is expected to cause the phase instability of black α-FAPbI 3 phase perovskite. When bromine is incorporated into the perovskite octahedron, the fraction of actively rotating FA molecules get reduced, resulting in the black phase stabilization. In this context, it has been reported here a method to grow single crystals of FA 0.9 MA 0.05 Cs 0.05 PbI 3-x Br x (x = 0, 0.3, 0.6 and 0.9) without yellow δ- FAPbI 3 phase formation using bromine doping into the precursor solution. Further research into the effect of bromine content on the long-term stability of grown single crystals revealed that keeping the bromine content at 10 M percentage can extend the lifetime of the multi-cation perovskite single crystals over a month.

Br Vacancy Defects Healed Perovskite Indoor Photovoltaic Modules with Certified Power Conversion Efficiency Exceeding 36.

Indoor photovoltaics (IPVs) are expected to power the Internet of Things ecosystem, which is attracting ever-increasing attention as part of the rapidly developing distributed communications and electronics technology. The power conversion efficiency of IPVs strongly depends on the match between typical indoor light spectra and the band gap of the light absorbing layer. Therefore, band-gap tunable materials, such as metal-halide perovskites, are specifically promising candidates for approaching the indoor illumination efficiency limit of ∼56%. However, perovskite materials with ideal band gap for indoor application generally contain high bromine (Br) contents, causing inferior open-circuit voltage (VOC ). By fabricating a series of wide-bandgap perovskites (Cs0.17 FA0.83 PbI3- x Brx , 0.6 ≤ x ≤ 1.6) with varying Br contents and related band gaps, it is found that, the high Br vacancy (VBr ) defect density is a significant reason that leading to large VOC deficits apart from the well-accepted halide segregation. The introduction of I-rich alkali metal small-molecule compounds is demonstrated to suppress the VBr and increase the VOC of perovskite IPVs up to 1.05V under 1000 lux light-emitting diode illumination, one of the highest VOC values reported so far. More importantly, the modules are sent for independent certification and have gained a record efficiency of 36.36%.

Wavelength Selective Solar Cells Using Triple Cation Perovskite.

Perovskite materials offer high-efficiency low-cost solar cells and applications versatility. We report on cesium-based hybrid perovskite solar cells with wavelength-selective properties ranging from 500 nm (UV-VIS) to 800 nm (IR). The band gap tuning was achieved through composition changes of mainly lead(II) iodide PbI2 and lead(II) bromide PbBr2. The optical spectra of the developed materials were studied, including the photoluminescence (PL), optical transparency, X-ray diffraction and external quantum efficiency for samples prepared under different compositions. It was found that a high content of iodine displayed a photoluminescence (PL) peak at 790 nm, whereas a high content of bromine showed a PL peak at 548 nm. The combined composition mixture of PbI2 and PbBr2 can be fine-tuned to prepare materials that absorbed light in the visible range (640–660 nm) or other selective wavelengths in the range from 500 to 800 nm. The illuminated current-voltage characteristics of the solar cells were carried out under the AM 1.5 condition using an ABET solar simulator with a reference solar cell for comparison and control. The average efficiency of the fabricated solar cells ranged from 3.5% to 15.5%, depending on perovskite composition. Wavelength-selective solar cells have potential applications in smart windows, building of integrated PVs and solar-operated greenhouses.

Modification of Disinfection Process at a Local Water Treatment Plant—Skawina (Poland)

This paper summarizes studies undertaken at a water treatment plant in Skawina (WTP Skawina) where the disinfection process was modified by introducing a mobile ozonation system. The application of a small-size, fully-automated ozonation installation only slightly complicates the water treatment process, without the need to redesign the water treatment line, and with relatively low investment costs. The aim of this study was to analyze whether the change of the disinfection method affects the final water quality. The investigated water samples were treated in the mobile ozonation system using a disinfection process with only sodium hypochlorite. Treated water was of excellent quality, and seasonal variations in raw water parameters (variable organic matter contents) did not result in elevated trihalomethanes (THM) and bromate concentrations. Despite the trace amounts of bromides in the water prior to treatment, the water in the municipal drinking water system did not contain determinable amounts of bromates. The bromine concentrations in the treated water supplied to the water distribution system were higher than in raw water, which could be attributable to the presence of bromine as a contaminant in sodium hypochlorite (the disinfection agent). Water quality tests carried out by the water treatment plant (WTP) and by the State Sanitary Inspectorate after the modification of the process line confirmed the high quality of water in the distribution network after the change of disinfection method.

Brominated Porous Nitrogen-Doped Carbon Materials for Sodium-Ion Storage

Chemical modification improves the performance of the carbon anode in sodium-ion batteries (SIBs). In this work, porous nitrogen-doped carbon (PNC) was obtained by removing template nanoparticles from the thermal decomposition products of calcium glutarate and acetonitrile vapor. The treatment of PNC with a KOH melt led to the etching of the carbon shells at the nitrogen sites, which caused the replacement of some nitrogen species by hydroxyl groups and the opening of pores. The attached hydroxyl groups interacted with Br2 molecules, resulting in a higher bromine content in the brominated pre-activated sample (5 at%) than in the brominated PNC (3 at%). Tests of the obtained materials in SIBs showed that KOH activation has little effect on the specific capacity of PNC, while bromination significantly improves the performance. The largest gain was achieved for brominated KOH-activated PNC, which was able to deliver 234 and 151 mAh g−1 at 0.05 and 1 A g−1, respectively, and demonstrated stable long-term operation at 0.25 and 0.5 A g−1. The improvement was related to the separation of graphitic layers due to Br2 intercalation and polarization of the carbon surface by covalently attached functional groups. Our results suggest a new two-stage modification strategy to improve the storage and high-rate capability of carbon materials in SIBs.

Kinetic modelling of the bromine-ammonia system: Formation and decomposition of bromamines

Bromamines i.e. monobromamine (NH2Br), dibromamine (NHBr2), and tribromamine (NBr3) can be formed during oxidative treatment of waters containing bromide and ammonia. The formation and decomposition of bromamines in aqueous solution was investigated and a comprehensive kinetic model of the bromine-ammonia system was developed at 23 ± 1 °C. Determination of rate constants and model validation were primarily performed at pH 8.0 – 8.3 for subsequent application to seawater disinfection. The rate constant of NHBr2 self-decomposition was determined by second-order rate law linearization with k9 = 5.5 (± 0.8) M−1s−1 at pH 8.10. The rate constant of NBr3 self-decomposition increased proportionately to the concentration of hydroxide ions (OH−) according to the equation k10 = 4.4 (± 0.1) × 107. [OH−] over the pH range 6.0 – 8.5, which gave k10 = 56 (± 1) M−1s−1 at pH 8.10. The rate constants of NHBr2 and NBr3 formation were obtained by fitting model-predicted data to the experimental results and were found to be k3 = 2.3 (± 0.2) × 104M−1s−1 and k5 = 4.0 (± 0.6) × 103M−1s−1, respectively at pH 8.10. NBr3 was also found to react with NHBr2 with k11 = 3.4 (± 0.2) × 103M−1s−1 at pH 8.10. A kinetic model was proposed based on these experimental rate constants and literature values, which provided a good prediction of bromamines formation and decomposition for various initial bromine and ammonia concentrations. The kinetic model was also used to accurately predict the total oxidant concentration and the speciation of bromamines during breakpoint bromination. This study provides kinetic data to model more complex oxidative systems such as seawater chlorination in the presence of ammonia.

Monthly variations of unregulated brominated disinfection by-products in chlorinated water are correlated with total bromine

Brominated disinfection by-products (Br-DBPs) can form during chlorination of drinking water in treatment plants (DWTP). Regulations exist for a small subset of Br-DBPs; However, hundreds of unregulated Br-DBPs have been detected and limited information exists on their occurrence, concentrations, and seasonal trends. Here, a data-independent precursor isolation and characteristic fragment (DIPIC-Frag) method was optimized to screen chlorinated waters for Br-DBPs. There were 553 Br-DBPs detected with m/z values ranging from 170.884 to 497.0278 and chromatographic retention times from 2.4 to 26.2 min. With MS 2 information, structures for 40 of the 54 most abundant Br-DBPs were predicted. The method was then applied to a year-long study in which raw, clear well, and finished water were analyzed monthly. The 54 most abundant unregulated Br-DBPs were subjected to trend analysis. Br-DBPs with higher oxygen-to-carbon (O/C) and bromine-to-carbon (Br/C) ratios increased as water moved from the clear well to the finished stage, which indicated the dynamic formation of Br-DBPs. Monthly trends of unregulated Br-DBPs were compared to raw water parameters such as natural organic matter, temperature, and total bromine, but no correlations were observed. It was found that total concentrations of bromine (TBr) in finished water (0.04–0.12 mg/L) were consistently and significantly greater than in raw water (0.013–0.038 mg/L, P < 0.001), suggesting the introduction of bromine during the disinfection process. Concentrations of TBr in treatment units, rather than raw water, were significantly correlated to 34 of the Br-DBPs at α = 0.05. This study provides the first evidence that monthly trends of unregulated Br-DBPs can be associated with the concentration of TBr in treated waters. - Ultrahigh resolution mass spectrometry was used to identify novel brominated disinfection byproducts in a Canadian water treatment facility. - Several hundred novel brominated compounds were identified of which 54 were assigned chemical structures. - Seasonal variation in the generated DBPs were assessed over 11 months of sampling. - Increases in total bromine in drinking water was noted with progress thru the treatment process.