ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Wanqi Xu,Congcong Ni,Ning Deng,Xin Huang
In persulfate-based advanced oxidation processes (PS-AOPs), sulfate radicals (SO 4 •- ) have been recognized to play more important roles in inducing bromate (BrO 3 − ) formation rather than hydroxyl radicals (HO • ) because of the stronger oxidation capacity of the former. However, this study reported an opposite result that HO • indeed dominated the formation of bromate instead of SO 4 •- . Quenching experiments were coupled with electron paramagnetic resonance (EPR) detection and chemical probe identification to elucidate the contributions of each radical species. The comparison of different thermal activated persulfates (PDS and PMS) demonstrated that the significant higher bromate formation in HEAT/PMS ([BrO 3 − ]/[Br − ] 0 = 0.8), as compared to HEAT/PDS ([BrO 3 − ]/[Br − ] 0 = 0.2), was attributable to the higher concentration of HO • radicals in HEAT/PMS. Similarly, the bromate formation in UV/PDS ([BrO 3 − ]/[Br − ] 0 = 1.0), with a high concentration of HO • , further underscored the dominant role of HO • . As a result, we quantified that HO • and SO 4 •- radicals accounted 66.7% and 33.3% for bromate formation. This controversial result can be reconciled by considering the critical intermediate, hypobromic acid/hypobromate (HOBr/BrO − ), involved in the transformation of Br − to BrO 3 − . HO • radicals have the chemical preference to induce the formation of HOBr/BrO − intermediates (contributing ∼ 60%) relative to SO 4 •- radicals (contributing ∼ 40%). This study highlighted the dominant role of HO • in the formation of bromate rather than SO 4 •- in PS-AOPs and potentially offered novel insights for reducing disinfection byproduct formation by controlling the radical species in AOPs.
研究领域:
环境科学
·
化学工程
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yao Tang,Xiaoyu Zhou,Ming Lei,Huimin Wang,Anqi Lu,Guihua Zhang,Lihua Zhu,Kangle Lv,Heqing Tang
It is still urgently needed to clarify how the reductive dehalogenation is accelerated by the interaction between the catalyst and the reducing agent. In the present work, both Pd and Cu were observed to induce the debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) with hydrazine hydrate (N 2 H 4 ·H 2 O) as reducing agent. In the case of Pd system, all the added BDE47 was debrominated to bromine-free products within 20 min. However, much different debromination behaviors of BDE47 were observed when Cu was used as the catalyst: in the initial stage the debromination efficiency of BDE47 could reach up to 55.3% within 0.5 min; nevertheless the complete debromination could not be achieved by prolonging reaction time. With the aid of DFT calculations, the above-mentioned great differences were attributed to the affinity of Pd to both H and N atoms, and strong Cu–N coordination existed between Cu and the adsorbed hydrazine molecules. The dissociation energy for the cleavage of N–H and N-N bonds of N 2 H 4 ·H 2 O adsorbed on Cu was very low, and hence the debromination of BDE47 was ultra-fast due to the spontaneously cleavage of N–H bond but it was inhibited at the later stage by the generated ammonium species (poisoning effect to the Cu catalyst) due to N-N bond cleavage. In contrast, the dissociation energy for the cleavage of N–H bond on the surface of Pd was higher and no ammonium was detected. These guarantee the continuously fast and complete debromination of BDE47 and its intermediates. These new insights to the catalytic mechanism through the interaction between the catalyst and the reducing agent will help to construct an efficient system to remove halogenated organic pollutants .
研究领域:
环境化学
·
催化
·
污染物去除
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DOI
高影响因子
WATER RESEARCH
·
2015
·
IF 5.528
Zhaobing Li,Zhi Chen,Yingying Xiang,Li Ling,Jingyun Fang,Chii Shang,Dionysios D. Dionysiou
Bromate formation in bromide-containing water through the cobalt (Co)-mediated activation of peroxymonosulfate (PMS) was investigated. Increasing the PMS dosage and the cobalt dosage increased the formation of bromate and bromate yields of up to 100% were recorded under the test conditions. The bromate yield increased to a maximum as the pH rose from 2.7 to 6 before decreasing by over 90% as the pH rose further from 6 to above 9. The bromate formation is a two-step process involving free bromine as a key intermediate and bromate as the final product. In the first step, apart from the known oxidation of bromide to free bromine and of free bromine to bromate by sulfate radicals (SO 4 − ), Co(III) produced from the oxidation of Co(II) by PMS and SO 4 − also oxidizes bromide to free bromine. The contribution of Co(III) to the bromate formation was verified with the addition of methanol and EDTA, a radical scavenger and a Co(III) ligand, respectively. In the presence of methanol, free bromine formation increased with increasing Co(II) dosage but no bromate was detected, indicating that Co(III) oxidized bromide to form free bromine but not bromate. In the presence of both EDTA and methanol, no free bromine or bromate was detected, as Co(III) was stabilized by EDTA to form the Co III EDTA – complex, which could not oxidize bromide. Mathematical simulation further suggested that Co(III) outweighed SO 4 − to oxidize bromide to free bromine. On the other hand, SO 4 − is essential for the oxidation of free bromine to bromate in the second step. In real water, the presence of NOM significantly decreased the bromate formation but caused the brominated organic DBP formation with high quantity. This is the first study to demonstrate the significant bromate formation in the Co/PMS system and the substantial contribution of Co(III) to the formation.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2020
·
IF 2.369
Xue-ping Zhang,Wei Wang,Han-zhong Zhang,Shi-hua Sang
In this paper, the stable phase equilibrium data of the ternary system CaBr2-SrBr2-H2O at T = 273, 298, and 323 K and 101.3 kPa have been determined by isothermal the dissolution equilibrium method. The phase diagrams of them at the investigated temperatures have been drawn. It is found that the isothermal phase diagrams of the CaBr2–SrBr2–H2O system at T = 273, 298, and 323 K are classified as a simple co-saturation type consisting of an invariant point and two univariant curves. The equilibrium solid phases corresponding to an invariant point of the system were detected as CaBr2·6H2O + SrBr2·6H2O at 273 and 298 K and those identified as CaBr2·4H2O + SrBr2·6H2O at 323 K. In this system, calcium bromide exhibits a strong salting-out effect on strontium bromide. Furthermore, isothermal solubilities at three temperatures were compared and discussed.
研究领域:
化学
·
材料科学
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产品关联
DOI
高影响因子
Processes
·
2022
·Vol. 10
·期 5
·823
·
IF 3.352
Bin Li,Xinjun Jing,Junsheng Yuan
The phase equilibria of the reciprocal quaternary system LiBr-Li2SO4-KBr-K2SO4-H2O and its ternary sub-systems LiBr-Li2SO4-H2O and KBr-K2SO4-H2O at 308.15 K were studied using the isothermal dissolution equilibrium method. Then, the solubility data of the equilibrium solutions were collected, and the phase diagrams were plotted. The phase diagrams of the ternary sub-systems at 308.15 K were compared with those at other temperatures. This study found that the phase diagram of the LiBr-Li2SO4-H2O system at 308.15 K consisted of an invariant point, two solid-phase crystallization regions of Li2SO4·H2O and LiBr·2H2O, and their corresponding solubility curves. The system generated two hydrated salts, which belonged to the hydrate type I phase diagram. The phase diagram of the KBr-K2SO4-H2O system at 308.15 K consisted of an invariant point, two univariant solubility curves, and two solid-phase crystallization regions of KBr and K2SO4, and no solid solution and double salts were formed. Thus, it belonged to a simple co-saturation type phase diagram. In the LiBr-Li2SO4-KBr-K2SO4-H2O system, K2SO4·Li2SO4double salt formed at 308.15 K, and the phase diagram consisted of three invariant points, five crystallization regions, and seven univariant solubility curves.Keywords:lithium bromide;potassium bromide;lithium sulfate;potassium sulfate;phase equilibrium
研究领域:
化学
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材料科学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Ziying Wang,Na An,Yisheng Shao,Naiyun Gao,Erdeng Du,Bin Xu
Bromide (Br − ), which is omnipresent in water bodies, can not only affect the degradation kinetics of target pollutants but may also form undesired byproducts (such as bromate ( BrO 3 - ) and brominated disinfection byproducts (Br-DBPs)) through sulfate radical ( SO 4 ∙ - )-based advanced oxidation processes (AOPs). This study found that Br − significantly suppressed the degradation of diethyl phthalate (DEP) based on the ultraviolet (UV)/persulfate (PS) treatment and was efficiently converted into reactive species (radicals and free bromine) by the SO 4 ∙ - or hydroxyl radical (HO ) generated in the UV/PS system. These reactive bromine species could, in turn, brominate the phenolic degradation intermediates of DEP as well as natural organic matter (NOM), yielding Br-DBPs, including tribromomethane (TBM), which was observed when Br − , DEP and/or NOM coexisted in this UV/PS system. However, the Br-DBPs were a short-lived form of bromine during the transformation of Br – and were degraded by the excessive oxidants (e.g., S O 4 ∙ - and HO ). Instead, Br − was eventually transformed into BrO 3 - , with free bromine acting as the requisite intermediate. The BrO 3 - formation initially showed a delay before increasing monotonically. In general, raising the PS dosage and the initial Br − concentrations enhanced both the maximum concentration of TBM and the formation of BrO 3 - , while increasing the amounts of DEP and NOM facilitated the former and inhibited the latter. The maximum concentration of TBM increased while the formation of BrO 3 - was suppressed with increasing pH from 5.0 to 8.0. In addition, through simulating the steady-state concentration of radicals, it was found that the contribution of bromine atom radical (Br ) towards oxidizing free bromine to BrO 3 - was far greater than those of S O 4 ∙ - and HO . The findings demonstrate the potential negative effects of Br − on SO 4 ∙ - -based AOPs, which need to be considered when this technology is applied in practice.
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2017
·
IF 5.099
Man Ren,Hao Zeng,Ping-An Peng,Hui-Ru Li,Cai-Ming Tang,Jian-Fang Hu
Polybrominated dibenzo- p -dioxins (PBDDs) and hydroxylated polybrominated diphenyl ethers (OH-PBDEs) can be formed from bromophenols (BPs) by thermal degradation , biosynthesis or phototransformation. However, it is unknown whether PBDDs and OH-PBDEs can be formed during the chemical production processes that utilize BPs as raw materials. 2,4,6-tribromophenol (2,4,6-TBP) is an important raw material for the synthesis of 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), a novel brominated flame retardant . In this study, PBDDs, polybrominated dibenzofurans (PBDFs) and OH-PBDEs have been identified and quantified in commercially available BTBPE and 2,4,6-TBP. Furthermore, their formation as unintentional by-products during the laboratory synthesis of BTBPE from 2,4,6-TBP and 1,2-dibromoethane in the presence of sodium carbonate has also been investigated. 2,3,7,8-substituted PBDDs and PBDFs (2,3,7,8-PBDD/Fs) were undetectable in commercial samples of BTBPE and present in low levels (nanogram per gram) in 2,4,6-TBP. Two tetrabrominated dibenzo- p -dioxins (TeBDDs), namely 1,3,6,8- and 1,3,7,9-TeBDD, and three hydroxylated pentabrominated diphenyl ethers (OH-pentaBDEs), namely 4′-OH-BDE121, 2′-OH-BDE121, and 6′-OH-BDE100, were identified or tentatively identified, and quantitatively estimated to be at concentrations in the range of undetectable to several thousands of nanograms per gram in commercial BTBPE and 2,4,6-TBP. TeBDDs and OH-pentaBDEs were formed as by-products from 2,4,6-TBP during BTBPE synthesis. Further studies need to be conducted in order to determine whether PBDD/Fs and OH-PBDEs are also formed during the industrial synthesis of other chemical compounds that utilize BPs as raw materials or intermediates.
研究领域:
环境科学
·
毒理学
·
化学
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2015
·
IF 5.528
Junhe Lu,Jinwei Wu,Yuefei Ji,Deyang Kong
Sulfate radicals ( S O 4 − · ) are applied to degrade various organic pollutants. Due to its high oxidative potential, S O 4 − · is presumed to be able to transform bromide to reactive bromine species that can react with natural organic matter subsequently to form brominated products including brominated disinfection by-products (Br-DBPs). This research was designed to investigate the transformation of bromide in thermo activated persulfate oxidation process in the presence of humic acid (HA). Significant formation of bromoform and bromoacetic acids was verified. Their formation was attributed to the reactions of HA and reactive bromine species including Br·, B r 2 − · HOBr − , and free bromine resulted from the oxidation of bromide by S O 4 − · . Yields of Br-DBPs increased monotonically at persulfate concentration of 1.0 mM and working temperature of 70 °C. However, the time-depended formation exhibited an increasing and the decreasing profile when persulfate was 5.0 mM, suggesting further degradation of organic bromine. HPLC/ICP-MS analysis demonstrated that the organic bromine was eventually transformed to bromate at this condition. Thus, a transformation scheme was proposed in which the bromine could be recycled multiple times between inorganic bromide and organic bromine before being finally transformed to bromate. This is the first study that reveals the comprehensive transformation map of bromine in S O 4 − · based reaction systems, which should be taken into consideration when such technologies are used to eliminate contamination in real practice.
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Libin Fu,Xueqin Peng,Qi Chen,Yaobin Ding,Jizhou Jiang
Photolysis and debromination of bromophenols were widely investigated previously. However, the role of reactive species especially hydrated electrons (e aq − ) in their degradation was overlooked. Therefore, in the study, generation and role of the reactive species generated during the photolysis of bromophenols were identified and evaluated by using 2,4,6-tribromophenol (TBP) as a model at different pH values from 4 to 11 under anaerobic condition. It was found that photolysis of TBP solution under UV irradiation (254 nm) yielded organic radicals (C•), hydrogen radicals (H•) and e aq − . By using nitrite and monochloroacetic acid (MCAA) as scavengers of H•/e aq − , the role of UV direct photolysis, H• and e aq − in degradation of TBP was quantitatively assessed at different initial pH (pH 0 ) values. UV irradiation induced direct photolysis of TBP was mainly dependent on its molar absorbance coefficient (ε) at 254 nm. Contribution rate of UV irradiation to degradation of TBP was about 60% at pH 0 4, 7 and 11. Interestingly, the contribution rate of e aq − was high as 35.8%-40% at pH 0 4–11, while the contribution rate of H• was negligible (<2.5%) at these pH values. Accordingly, UV and e aq − induced degradation and debromination pathways of TBP under UV irradiation were proposed. This work gains deep insight into the photolysis process of bromophenols, and clarifies the important role of e aq − in photo-degradation of bromophenols.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
Frontiers in Chemistry
·
2023
·
IF 5.5
Cui Ruizhi,Peng Changwei,Nie Guoliang,Sang Shihua,Ren Hongbao,Li Wu
In view of the composition characteristics of lithium, calcium and bromine rich in Nanyishan oil and gas field brine of western Qaidam Basin, Qinghai Province, as well as based on the results reported in relevant literature, the phase equilibrium relationship of ternary system LiBr-CaBr2-H2O at 298.15 K was studied by isothermal dissolution equilibrium method. The equilibrium solid phase crystallization regions, as well as the compositions of invariant point, in phase diagram of this ternary system were clarified. On basis of the above ternary system research, the stable phase equilibria of quaternary systems (LiBr-NaBr-CaBr2-H2O, LiBr-KBr-CaBr2-H2O and LiBr-MgBr2-CaBr2-H2O), as well as quinary systems (LiBr-NaBr-KBr-CaBr2-H2O, LiBr-NaBr-MgBr2-CaBr2-H2O and LiBr-KBr-MgBr2-CaBr2-H2O) were further carried out at 298.15 K. According to the above experimental results, the corresponding phase diagrams at 298.15 K were drawn, which revealed the phase relationship of each component in solution and the law of crystallization and dissolution, and meanwhile summarized changing trends. The research results of this paper lay a foundation for further research on the multitemperature phase equilibria and thermodynamic properties of lithium and bromine containing high-component brine system in later stage, and also provide basic thermodynamic data for guiding the comprehensive development and utilization of this oil and gas field brine resource.
研究领域:
化学
·
热力学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Lu Wang,Ke Jing,Baowei Hu,Junhe Lu
Formation of halogenated oxidation by-products (OBPs) in sulfate radical based advanced oxidation process (SR-AOPs) has raised growing concern. In the present study, we found that brominated OBPs (Br-OBPs) were generated in heat-activated peroxydisulfate (PDS) oxidation of humic acid (HA) in the presence of Br − . The yields of bromoform, dibromoacetic acid, and tribromoacetic acid reached 2.52, 2.01, and 0.11 μM, respectively, in 2 h at a working temperature of 60 °C with an initial Br − , PDS, and HA concentrations of 0.1 mM, 5.0 mM, and 2.0 mg/L, respectively. Similar results were found when HA was replaced by 3,5-dihydroxybenzoic acid (DHBA) as the substrate, suggesting that the phenolic moieties in HA molecules are the reactive sites for halogenation. Almost no Br-OBPs could be detected when 5.0 mM H 2 O 2 was added to the reaction solutions. The reduced Br-OBPs formation was due to the reduction of free bromine by H 2 O 2. Both experimental data and kinetic modeling indicated that the concentration of free bromine decreased significantly in the presence of H 2 O 2 . However, H 2 O 2 did not eliminate the formation of organic bromines completely. Certain brominated DHBA intermediates formation in the presence of H 2 O 2 was even higher than that with H 2 O 2 absent. Bromine radicals, such as Br 2 − and HBrO − , are presumed responsible for the organic bromines. Without free bromine, these organic bromines were relative stable and could not be further degraded to small molecule Br-OBPs. The findings of this study indicate that adding H 2 O 2 to SR-AOPs can significantly suppress the generation of halogenated-OBPs. However, the formation of organic bromines is still a concern.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2018
·Vol. 25
·期 18
·18001-18014
·
IF 2.8
Xu Zhengming,Han Dexia,Li Yuan,Zhang Pingling,You Lijun,Zhao Zhengang
In this study, the FPA90-Cl resin was magnetized with supported Fe 3 O 4 particles using a chemical co-precipitation method and its removal performance of bromate and coexisting precursors was explored. The magnetized FPA90-Cl resin was structurally characterized by SEM, FT-IR, and XRD. The effects of the initial concentrations, temperature, and resin dosage on bromate and bromide ion removal in drinking water were investigated using batch experiments. The magnetized FPA90-Cl resin exhibited a high removal efficiency for bromate and bromide ions at three initial concentrations, and the residual bromate concentrations were under the maximum contaminant level (MCL) of 10 μg L −1 after 80 min. The adsorption data of bromate and bromide ion could be well described by a pseudo-first-order kinetic model ( R 2 ˃ 0.98). The bromate removal alone was further studied by varying the initial solution pH, temperature, and competitive anions. The results showed that the magnetized FPA90-Cl resin could be used over a wide pH range (4.0–9.0). The maximum sorption capacity of the magnetized FPA90-Cl resin for bromate reached 132.83 mg g −1 at 298 K. The Freundlich and Redlich-Peterson isotherm models fit the bromate adsorption equilibrium better ( R 2 ˃ 0.99) than the Langmuir isotherm model ( R 2 ˃ 0.98). The thermodynamic analysis showed that the bromate adsorption process was endothermic. The negative ΔG and positive ΔS indicated that the process was spontaneous and that randomness increased after adsorption, respectively. The competition of coexisting anions with bromate was in the order of SO 4 2− > CO 3 2− > Cl − > NO 3 − > HCO 3 − > PO 4 3− . Additionally, the magnetized FPA90-Cl resin could maintain a high bromate and bromide ion adsorption capacity after five cycles of regeneration by a 0.1 M NaCl solution.
Graphical abstract
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）