Bromide Ions Research Articles

Measurements of mean activity coefficients and solubility prediction in ternary system KBr-K2SO4-H2O at 308.15 K and 288.15 K

In this work, the mean activity coefficients of KBr in KBr-H2O binary system and KBr-K2SO4-H2O ternary system were determined at 308.15 K and 288.15 K by the cell potential method. The potassium ion selective electrode and bromide ion selective electrode are used to measure the cell potential value of single salt electrolyte solution,and the standard potential value E0 and electrode response slope k of the binary system are obtained. The experimental results showed that ion selective electrodes of used in this work had a good Nernst response. The mean activity coefficients KBr in KBr-K2SO4-H2O system are also determined, the total ionic strength in the mixed solution ranging from (0.0100 to 1.0000) mol·kg−1, and ionic strength fractions yb of K2SO4 with yb=(0.8, 0.6, 0.4, 0.2 and 0.0). Using mean activity coefficients obtained in this work and Pitzer model, the Pitzer mixed ion interaction parameters θBr,SO4 and ψK,Br,SO4are fitted respectively. Furthermore, those osmotic coefficient Φ, water activity aw, excess Gibbs free energy GE were also calculated by Pitzer’s equations. The solubilities of salts in the KBr-K2SO4-H2O system at 308.15 K and 288.15 K are predicted by using Pitzer equations and ion interaction parameters fitted in this work, and phase diagrams of the ternary system are also plotted according to the calculated solubilities. The results show that the ion interaction parameters of Pitzer equations by fitting the activity coefficients can be used for calculation thermodynamic parameters and prediction of phase equilibria.

Precursor characteristics of mono-HAAs during chlorination and cytotoxicity of mono-HAAs on HEK-293T cells.

Monohaloacetic acids (mono-HAAs), a class of disinfection by-products widely occurred in drinking water, receives significant attention due to their extremely high toxicity. Many studies on the biological toxicity of mono-HAAs have been reported, yet the toxic effects of mono-HAAs on human renal cells (kidney is one of the target organs for disinfection by-products) has not been involved. Studies on organic precursors for mono-HAAs formation were also very limited due to their lower levels as compared to di-HAAs and tri-HAAs. Based on this, the formation of mono-HAAs after chlorination of some typical source water samples and their relationship with water quality parameters were investigated. Meanwhile, the cytotoxicity of monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), and monoiodoacetic acid (MIAA) were tested using human embryonic kidney cells (HEK-293T cells). The results showed that the levels of mono-HAAs formed during chlorination of source water samples were between 0.44 and 0.87μg/L. Formation of MBAA positively (p<0.05) correlated with bromide ion and dissolved organic carbon, but negatively (p<0.01) correlated with SUVA254 (specific UV absorbance at 254nm), while formation of MCAA was only positively (p<0.05) related with SUVA254. These results suggested that although MCAA and MBAA both belong to the mono-HAAs, the characteristics of their organic precursors differ significantly. MCAA precursors have high aromaticity and are more hydrophobic, yet MBAA precursors have low aromaticity and are more hydrophilic. The half-lethal concentrations (LC50) of MCAA, MBAA, and MIAA on HEK293T cells were 1196-1211μM, 16.07-18.96μM, and 6.08-6.17μM, respectively. An in-depth analysis showed that the cytotoxicity of mono-HAAs on HEK 293T cells could not be explained by the parameters concerning cellular uptake (e.g., logP and pKa), but the SN2 reaction of C-X bond with cellular molecules (e.g., glyceraldehyde-3-phosphate dehydrogenase, etc) may be the relevant cause for the cytotoxicity of mono-HAAs on HEK 293T cells.

Enhanced removal of ammonia in Fe(VI)/Br− oxidation system: Kinetics, transformation mechanism and theoretical calculations

This work systematically examined the capability of ferrate (Fe(VI)) for ammonia oxidation, revealing for the first time that bromide ions (Br−) played an important role in promoting the removal of ammonia in Fe(VI) system. In the presence of 10.0 mM Br−, the removal efficiency of ammonia was nearly 3.4 times that of the control, and 1.0 mM ammonia was almost completely removed after two rounds addition of 1.0 mM Fe(VI) in 60 min. PMSO probe test, electron paramagnetic resonance spectra and radical quenching experiments were employed to interpret the underlying promotion mechanism of Br−, and it was proposed that the formation of active bromine (HOBr/OBr−) played a dominant role in the enhanced oxidative removal of ammonia by Fe(VI). Further kinetic model simulations revealed that HOBr/OBr− and Fe(VI) were the two major reactive species in Fe(VI)/Br− system, accounting for 66.7% and 33.0% of ammonia removal, respectively. As the target contaminant, ammonia could quickly consume the generated HOBr/OBr−, thereby suppressing the formation of brominated disinfection byproducts. Finally, NO3− was identified as the dominant transformation product of ammonia, and density functional theory (DFT) calculations revealed that six reaction stages were involved in ammonia oxidation with the first step as the rate-limiting step. This work would enable the full use of coexisting bromides for effective removal of ammonia from natural waters or wastewaters by in situ Fe(VI) oxidation method.

Investigating the effect of the simultaneous presence of bromide ions in the removal of dye from textile wastewater by the UV/Cl process

Investigating the effect of the simultaneous presence of bromide ions in the removal of dye from textile wastewater by the UV/Cl process

The influence of bromide and iodide ions on the sulfamethoxazole (SMX) halogenation during chlorination

Disinfection by-products (DBPs) were produced during the chlorination process, posing a threat to drinking water safety and human health. In the presence of bromide and iodide ions, brominated and iodinated DBPs will be generated, which might be more toxic than the parent compound. However, there are few studies on brominated and iodinated DBPs of antibiotics. Therefore, in this study, the fates of sulfamethoxazole (SMX) during chlorination in different systems (Blank; SMX + NaClO; SMX+ NaClO+ Br−; SMX+ NaClO+I−; SMX+ NaClO+ Br− + I−) were investigated. In different systems, all the reaction followed a pseudo-first-order kinetics, while the reaction rates of NaClO with SMX were different, the reaction rates were in order of SMX + NaClO + Br− + I− > SMX + NaClO + Br− > SMX + NaClO + I− > SMX + NaClO. When Br− and I− existed simultaneously, the reaction rate was the fastest. Iodide played an important role in oxidation and promoted the chlorination of SMX. SMX mainly underwent S-C cleavage, S-N hydrolysis, desulfonation, and substitution reactions. Nine disinfection by-products, including three reported for the first time, were identified using a non-targeted approach, and degradation pathways were proposed. Furthermore, EPI Suite software was applied to predict the environmental accumulation potential and environmental persistence of the degradation products. The results indicated that SMX and degradation products had little environmental accumulative potential and environmental persistence.

Spectroelectrochemical and ESR investigation of free radicals derived from indotricarbocyanine dyes for photodynamic therapy

Cyclic voltammetry, UV–Vis absorption spectroscopy, and electron spin resonance are applied to study the properties of indotricarbocyanine dyes and their radicals formed during electrooxidation. We use electrochemistry to generate relatively stable free radicals of the dyes under controlled conditions. The dyes undergo electrooxidation during the chronoamperometric electrolysis at 1.1 V (versus saturated calomel electrode) yielding radical dications. The radicals exhibit an absorption band that is blue-shifted relative to the parent dye (561 nm versus 714 nm). In acetonitrile solutions, the radicals are characterized by a lifetime of ca. 20 min and a g factor of 2.002. The oxidation potential of the dyes is slightly greater than that of bromide ions allowing the radicals of the dyes to interact with bromide ions. The ability of the indotricarbocyanine dyes to sensitize generation of highly reactive bromine radicals might play an important role in their photodynamic activity.

Dielectric, conductivity relaxation, conduction mechanisms and thermal behavior in 2-D Ruddlesden-Popper manganese bromide perovskite hybrid

Powder X-ray diffraction of [NH3(CH2)7(NH3)]MnBr4 perovskite hybrid crystallizes in the triclinic system with space group P‾1. Five phase transitions are identified by differential scanning calorimetric technique. Dielectric and AC conductivity measurements, in the temperature range (300–400) K and frequency range (0.06 kHz– 60 kHz) are in good agreement with DSC phase transitions. Proton conduction and bromide ion migration predominates in the intermediate and high temperatures respectively. The frequency dependence of the conductivity was fitted according to super-linear power law. Conduction mechanism is different in the different phases, (OLPT) and (NSPT) tunneling dominate in the temperature range (300–334) K, whereas correlated barrier hopping (CBH) is the mechanism at higher temperatures, with different carrier binding energies (Wm) for the different phases.

The Role of (BDMS) Bromodimethylsulfonium bromide as a Catalyst and Brominating Reagent: A Concise Overview

AbstractBromodimethylsulfonium bromide (BDMS) is an expedient storage of molecular bromine or bromine radicals or bromonium ions and also of nucleophilic bromide ion. It is an easily available, inexpensive and versatile reagent. It is used as an effective brominating reagent as well as a valuable catalyst for several organic conversions. The prominent characteristics of this compound are the straight forwardness of the process, the ease of access of the compound, no requirement of chromatographic separation, no additional base, Lewis acid, or any other catalyst, better yields in comparatively less reaction times and assist to maintain the stoichiometric ratio during the reactions. The present article includes the catalytic applications as well as its brominating role in organic reactions.

Zwitterion‐Functionalized SnO2 Substrate Induced Sequential Deposition of Black‐Phase FAPbI3 with Rearranged PbI2 Residue

Black-phase formamidinium lead iodide (FAPbI3 ) with narrow bandgap and high thermal stability has emerged as the most promising candidate for highly efficient and stable perovskite photovoltaics. In order to overcome the intrinsic difficulty of black-phase crystallization and to eliminate the lead iodide (PbI2 ) residue, most sequential deposition methods of FAPbI3 -based perovskite will introduce external ions like methylammonium (MA+ ), cesium (Cs+ ), and bromide (Br- ) ions to the perovskite structure. Here a zwitterion-functionalized tin(IV) oxide (SnO2 ) is introduced as the electron-transport layer (ETL) to induce the crystallization of high-quality black-phase FAPbI3 . The SnO2 ETL treated with the zwitterion of formamidine sulfinic acid (FSA) can help rearrange the stack direction, orientation, and distribution of residual PbI2 in the perovskite layer, which reduces the side effect of the residual PbI2 . Besides, the FSA functionalization also modifies SnO2 ETL to suppress deep-level defects at the perovskite/SnO2 interface. As a result, the FSA-FAPbI3 -based perovskite solar cells (PSCs) exhibit an excellent power conversion efficiency of up to 24.1% with 1000 h long-term operational stability. These findings provide a new interface engineering strategy on the sequential fabrication of black-phase FAPbI3 PSCs with improved optoelectronic performance.

Presence of bromide and iodide promotes the horizontal transfer of antibiotic resistance genes during chlorination: A preliminary study

Chlorination was reported to have a great potential to increase horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs), which poses a great threat to global human health. Bromide (Br−) and iodide (I−) ions are widely spread ions in water and wastewater. In chlorination, Br− and I− can be oxidized to active bromine and iodine species. The influence of the co-existing different halogen oxidants (chlorine + bromine or iodine species) on HGT of ARGs were rarely investigated. In this study, the conjugative transfer of ARGs between a donor strain E. coli K12 and a recipient strain E. coli HB101 was investigated in chlorination without/with the presence of Br− or I−. Immediately after the addition of sodium hypochlorite, 53–88 % of the dosed chlorine was rapidly consumed, 10 %–42 % fast transformed into organic combined chloramines, and only low levels of free chlorine (0.02–0.8 mg/L as Cl2) left in the diluted cultural medium. Conjugative transfer mediated by the RP4 plasmid was not significantly enhanced in chlorination without the presence of Br− or I−. With the presence of Br− (0.5–5.0 mg/L) or I− (0.05–0.5 mg/L) in chlorination, the co-existing free halogen oxidants and their organic combined ones up-regulated the mRNA expression of the oxidative stress-regulatory gene (rpoS), outer membrane protein gene (ompC), and conjugation-relevant genes (trbBp and trfAp), and caused more damage to cell entirety. As a result, the co-existing reactive halogen oxidants enhanced the HGT of ARGs probably via conjugative transfer and transformation. This study showed that the presence of Br− and I− of common levels in aquatic environment promoted HGT of ARGs in chlorination, thus accelerating the transmission and prevalence of ARGs.

Photochemical reactions of dissolved organic matter and bromide ions facilitate abiotic formation of manganese oxide solids

Manganese (Mn) oxide solids are ubiquitous in nature, acting as both electron donors and acceptors in diverse redox reactions in the environment. Reactions of Mn(III/IV) oxides with dissolved natural organic matter (DOM) are commonly described as reductive dissolutions that generate Mn2+(aq). In this study, we investigated the role of photochemical reactions of DOM in Mn2+(aq) oxidation and the resulting formation of Mn oxide solids. During the photolysis of DOM, reactive intermediates can be generated, including excited triplet state DOM (3DOM*), hydroxyl radicals (•OH), superoxide radicals (O2•−), hydrogen peroxide, and singlet oxygen. Among these, we found that O2•− radicals were mainly responsible for Mn oxidation. The solution pH controlled the formation of Mn oxide solids by affecting both Mn2+ oxidation by O2•− during photolysis of DOM and reductive dissolutions of Mn oxide solids by DOM. Further, with the addition of bromide ions (Br−), reactions between 3DOM* and Br−, together with reactions between •OH and Br−, can form reactive bromide radicals. The formed Br radicals also promoted Mn oxide formation. In DOM with more aromatic functional groups, more Mn2+ was oxidized to Mn oxide solids. This enhanced oxidation could be the result of promoted pathways from charge-transfer state DOM (DOM•+/•−) to O2•−. These new observations advance our understanding of natural Mn2+ oxidation and Mn(III/IV) oxide formation and highlight the underappreciated oxidative roles of DOM in the oxidation of metal ions in surface water illuminated by sunlight.

Interfacial Composition of Surfactant Aggregates in the Presence of Fragrance: A Chemical Trapping Study.

In recent years, there has been increasing interest in daily-use chemical products providing a pleasant scent. The added fragrance molecules may induce microstructural transitions of surfactant aggregates, which further affect the physical and chemical properties of the products. Here, the effects of four types of aromatic alcohols (cinnamyl alcohol, phenyl ethanol, phenyl methanol and anisyl alcohol) on cetyltrimethylammonium bromide (CTAB)/KBr aggregates were studied. The combined results from rheology, dynamic light scattering, and transmission electron microscopy measurements showed that cinnamyl alcohol induced significant micellar growth, while increases in micellar growth were less obvious for the other aromatic alcohols. The changes in the interfacial molarities of water, aromatic alcohol, and bromide ions during such transitions were studied using the chemical trapping method. Transitions resulting from added cinnamyl alcohol were accompanied by significant declines in interfacial water and bromide ion molarities, and a rise in interfacial alcohol molarity. The marked decrease in interfacial water molarity was not observed in previous studies of the octanol induced formation of wormlike micelles and vesicles, indicating that a different mechanism was presented in the current system. Nuclear magnetic resonance investigation showed that π–π stacking between cinnamyl alcohols, but not cation–π interactions between alcohols and CTAB headgroups, facilitated the tight packing of alcohol molecules in CTAB aggregates and the repulsion of water from the interfacial region. The current study may provide a theoretical basis for the morphological regulation of surfactant aggregates in the presence of additives.

Trihalomethane evaluation in chlorinated treated drinking water sources in Saudi Arabia (Aseer region a case study)

This study was conducted to assess trihalomethane levels in Aseer region's main chlorinated treated drinking water sources over four consecutive seasons (Summer, Autumn, Winter, and Spring) and to gain a better understanding of trihalomethane occurrence, amounts, and the factors involved in trihalomethane formation in study area particularly. The study covered thirteen varied drinking water sources including five conventional filtration treatment plants for surface water and two non-conventional treatment plants for groundwater in addition to six desalinated and blended drinking water reservoirs. Results of the study indicated that exceeded the permissible concentration of total trihalomethane at conventional filtration treatment plants of surface water with maximum values ranging from 111.16 ppb to 208.76 ppb with dominant brominated trihalomethane as bromoform (CHBl3) and dibromochloromethane (CHClBr2), especially during the summer season. Results also showed a positive correlation between trihalomethane formation and the level presence of some trihalomethane precursors like organic carbon, turbidity, bromide ion, and free chlorine whereas, a correlation was negative with pH values.

Elimination of acetaminophen in sodium carbonate-enhanced thermal/peroxymonosulfate process: Performances, influencing factors and mechanism

Peroxymonosulfate (PMS) is commonly poor for degrading organic contaminants through thermal activation because of the high O-O bond dissociation energy. This work is the first to demonstrate that sodium carbonate (Na2CO3) significantly promoted the degradation of acetaminophen with thermal/PMS process, and Na2CO3/thermal/PMS process exhibited faster removal rate of acetaminophen and a lower formation potential of BrO3− than Na2CO3/thermal/peroxydisulfate process. The increase of Na2CO3 dosage, PMS dosage and reaction temperature were favorable for acetaminophen degradation with Na2CO3/thermal/PMS process. Na2CO3/thermal/PMS process could generate multiple reactive species including 1O2 and the radicals of ·OH, SO4·− and CO3·−. 1O2 was dominant in acetaminophen removal regardless of the dosage of Na2CO3, while the radicals of ·OH, SO4·− and CO3·− also participated in the removal of acetaminophen. Three different degradation pathways of acetaminophen were proposed based on UPLC-Q-TOF-MS detection, and the toxicity towards luminescent bacteria and green algae significantly decreased. Humic acid slightly inhibited the removal of acetaminophen, sulfate ion and nitrate ion presented negligible effect on acetaminophen removal, while chloride ion and bromide ion greatly accelerated the elimination of acetaminophen. Na2CO3/thermal/PMS process exhibited wide suitability in eliminating acetaminophen in ground water and degrading other organic contaminants, including bisphenol A, naproxen, diclofenac, rhodamine B and acid orange 7. This work provided a promising method to enhance the oxidizing ability of thermal/PMS process and might promote its application in the remediation of contaminated water and soil.

ELECTROCHEMICAL MIGRATION FAILURE OF PURE TIN UNDER BROMIDE-POLLUTED THIN ELECTROLYTE LAYER

The electrochemical migration (ECM) time to failure (TTF) tests for pure tin in the bromide-containing environment were carried out using the thin electrolyte layer (TEL) method. In-situ electrochemical measurement was made to monitor the ECM behavior while the changes of surface morphology and localized pH during the ECM process were real-time observed using the 3D optical digital microscope. Microstructure and composition of products obtained after the ECM tests were characterized using the scanning electron microscope, energy-dispersive spectrometer and X-ray diffractometer. Results indicated that the growth rate of dendrite increased with bromide ion concentration at low bromide concentration levels, and it decreased at medium concentration levels. Tree-like tin dendrites covered with white precipitates are formed after the ECM tests. As for the high bromide ion concentration condition, no dendrite can be found and a thick layer of precipitate is formed between the twin electrodes. This precipitate layer has a higher thickness than the electrolyte layer, which can act as a barrier layer retarding ionic migration and thus inhibiting the ECM failure. Relevant mechanism has been proposed to clarify the effect of bromide ions on the ECM of pure tin under the thin electrolyte layer.

Tailoring the molecular structure of pyridine-based polymers for enhancing performance of anion exchange electrolyte membranes

Anion exchange membranes (AEMs) with high ionic conductivity and excellent chemical stability are desired for relevant electrochemical devices. We designed and prepared pyridine based ether free poly (biphenyl pyridine) (PBP) membranes by modifying pyridinium with both hydrophilic and hydrophobic end groups via the Menshutkin reaction. The grafted ethyl trimethyl ammonium and hexyl pendants assisted the formation of well-connected ion transport channels in the membranes according to the results of transmission electron microscopy (TEM). The highest conductivity of 117 mS cm−1 to hydroxide ions and 73 mS cm−1 to bromide ions was achieved, respectively, at 90 °C by the prepared membranes. The conductivity retention rate of the AEMs was within 84–93% after soaking in 1 mol L−1 KOH at 80 °C for 1008 h. The membrane-based single fuel cell exhibited an open circuit voltage of 0.99 V and a peak power density of 241 mW cm−2 at 80 °C by fueling with humidified H2 and O2 without backpressure. The aqueous zinc bromine battery with a composite separator of the polymer impregnated glass fiber achieved 92.6% of the coulombic efficiency. The assembled battery retained 98% of initial capacity after 157 cycles at a current density of 6 mA cm−2.

Alkyl Diamine-Induced (100)-Preferred Crystal Orientation for Efficient Pb–Sn Perovskite Solar Cells

The narrow band gap lead–tin (Pb–Sn) perovskite is a promising light absorption layer for highly efficient perovskite solar cells (PSCs), particularly for tandem applications. However, its random crystal orientation dramatically limits its power conversion efficiency (PCE). Here, a propane diamine bromide (PDABr) additive is developed to effectively modulate the Pb–Sn perovskite to grow along the (100)-preferred orientation. It is found that the PDA cations naturally anchor onto the colloidal perovskite nucleus to serve as a surface template to modulate the perovskite crystal to grow preferentially along its (100) orientation, while the bromide ions aid in increasing the grain size, resulting in a densely packed film with significantly reduced density of grain boundaries. As a result, the PDABr-based film exhibits increased carrier mobility and reduced defect density. With these merits, the PDABr-based Pb–Sn PSCs demonstrated an impressive PCE of 20.41%, which is much higher than that of the control device (16.23%). This work provides a general approach to realize the preferred crystal growth for Pb–Sn perovskite films to attain high optoelectronic performance.

1,1'-Methyl-enebis(4,4'-bipyridin-1-ium) dibromide.

The asymmetric unit of the title salt, C21H18N4 2+·2Br-, comprises half of the mol-ecule and a bromide ion. The chevron-shaped cations stack as columns in the [001] direction with suitable inter-molecular distance for π-π inter-actions. These cationic columns are further stabilized by inter-columnar C-H⋯N hydrogen bonding with the bromide ions distributed between them.

Suppressing Halide Segregation in Wide-Band-Gap Mixed-Halide Perovskite Layers through Post-Hot Pressing.

Mixed-halide perovskites (MHPs) have attracted attention as suitable wide-band-gap candidate materials for tandem applications owing to their facile band-gap tuning. However, when smaller bromide ions are incorporated into iodides to tune the band gap, photoinduced halide segregation occurs, which leads to voltage deficit and photoinstability. Here, we propose an original post-hot pressing (PHP) treatment that suppresses halide segregation in MHPs with a band gap of 2.0 eV. The PHP treatment reconstructs open-structured grain boundaries (GBs) as compact GBs through constrained grain growth in the in-plane direction, resulting in the inhibition of defect-mediated ion migration in GBs. The PHP-treated wide-band-gap (2.0 eV) MHP solar cells showed a high efficiency of over 11%, achieving an open-circuit voltage (Voc) of 1.35 V and improving the maintenance of the initial efficiency under the working condition at AM 1.5G. The results reveal that the management of GBs is necessary to secure the stability of wide-band-gap MHP devices in terms of halide segregation.

Co (II) Complexes Based on the Bis-Pyrazol-S-Triazine Pincer Ligand: Synthesis, X-ray Structure Studies, and Cytotoxic Evaluation

Four pincer-type Co (II) complexes of the 2,4-bis (3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine ligand (L) were evaluated for their cytotoxic activities against lung and breast cancer cell lines using cell viability assay. The X-ray single crystal structure of [Co(L)(H2O)2Br]Br (1) confirmed the pincer coordination behavior of the ligand L as an N-tridentate chelate. The hexa-coordination environment of Co (II) is completed by one bromide ion completing the equatorial plane of the octahedral structure and two trans water molecules at the axial positions. It crystallized in the monoclinic crystal system and P21/m space group with crystal parameters of a = 11.3170(10) Å, b = 7.4613(7) Å, c = 12.6917(12) Å and β = 95.927(3)°. Based on Hirshfeld analysis, the most dominant contacts are H…H (48.8%), Br…H (17.6%), H…C (11.2%) and O…H (10.1%), where the Br…H interactions are the most significant. The cytotoxic evaluation of the studied systems indicated that complex [Co(L)(NO3)2] (4) has the highest activity against lung (A-549) and breast (MCF-7) cell lines. In contrast, complex [Co(L)(H2O)3](ClO4)2.H2O(3) has the lowest cytotoxic activity against both cell lines.