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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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Xu Yin,Jiatian Yu,Zhifeng Gao,Wei Li,Kajia Wei,Yun Jiang,Yonghao Zhang,Haoming Chen,Weiqing Han
Bromate (BrO 3 – ) is a common by-product of advanced oxidation water treatment processes. In this study, a catalyst combining MXene and Pd was synthesized to eliminate BrO 3 – by electrochemical reduction in flow-through mode. The fabricated Ti/Pd@MXene filter showed superior activity for BrO 3 – reduction compared with Ti/MXene filter. A satisfactory BrO 3 − removal performance by Ti/Pd@MXene filter was obtained at pH values of 5–7 with a current density of 1.0–2.5 mA·cm –2 . The mechanism explored by quenching experiments and EPR analysis demonstrated that atomic hydrogen (H*)-mediated reduction was dominant in the Ti/Pd@MXene filter system and contributed to 84.2 % of the BrO 3 − removal, which was greater than that of Ti (7.1 %) and Ti/MXene (43.9 %). DFT calculations revealed the introduction of Pd nanoparticles on MXene lowered the energy barrier for generating H* from OH* -H* , thus boosting H* formation. Furthermore, the Ti/Pd@MXene filter had favorable stability and applicability, and nearly 90 % of BrO 3 − could be eliminated in different water matrices. Moreover, energy consumption of the Ti/Pd@MXene filter was more competitive than that previously reported (0.348 kWh·mmol −1 ), especially for high BrO 3 − removal (≥75 %). This work highlighted an effective flow-through electrocatalytic filter to induce H* -mediated electrochemical reduction of BrO 3 − .
研究领域:
环境科学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Xiaoyu Zhang,Qinqin Ma,Xinfang Liu,Huawei Niu,Lei Luo,Rongfang Li,Xun Feng
A new europium metal–organic framework ( Eu-MOF ) was prepared by simple hydrothermal method . The product exhibited intense red fluorescence, long fluorescence lifetime (0.454 ms) and excellent fluorescence stability. The fluorescence titration result showed that Fe 3+ could completely quench the fluorescence of Eu-MOF , while the fluorescence quenching effect of Fe 2+ or bromate was negligible. Considering the strong oxidizing property of bromate, a “turn off” Eu-MOF@Fe 2+ sensor toward bromate was designed by generating Fe 3+ due to the redox reaction . The results showed that the sensor displayed a wide linear range (0–0.2 mM), high sensitivity (LOD = 3.7 × 10 −6 mol/L), good selectivity and resistant to possible interferences in real four sample. Furthermore, the detection mechanism was investigated by PXRD, XPS and UV–Vis methods. More importantly, the Eu-MOF@Fe 2+ sensor was further applied to detect bromate in wheat flour with satisfactory recovery (95.30%−104.38%) and accuracy (RSD < 2.85%). These results suggest that Eu-MOF@Fe 2+ can be used as a potential sensor to detect bromate in food industry.
研究领域:
分析化学
·
食品安全
✓ 已验证
DOI
高影响因子
Catalysts
·
2017
·Vol. 7
·期 5
·131
·
IF 3.082
Xiaowei Liu,Lili Wang,Zhe Sun,Yu Shao,Tingchao Yu
Bromate (BrO3−) contamination in drinking water is a growing concern. Advanced reduction processes (ARPs) are reportedly promising in relieving this concern. In this work, UV/superparamagnetic BiOCl (BiOCl loaded onto superparamagnetic hydroxyapatite) assisted with small molecule carboxylic acid (formate, citrate, and acetate), a carboxyl anion radical (CO2•−)-based ARP, was proposed to eliminate aqueousBrO3−. Formate and citrate were found to be idealCO2•−precursor, and the latter was found to be safe for practical use.BrO3−(10 μg·L−1, WHO guideline for drinking water) can be completely degraded within 3 min under oxygen-free conditions. In this process,BrO3−degradation was realized by the reduction ofCO2•−(major role) and formyloxyl radical (minor role) in bulk solution. The formation mechanism of radicals and the transformation pathway ofBrO3−were proposed based on data on electron paramagnetic resonance monitoring, competitive kinetics, and degradation product analysis. The process provided a sustainable decontamination performance (<5% deterioration for 10 cycles) and appeared to be more resistant to common electron acceptors (O2,NO3−, and Fe3+) than hydrated electron based-ARPs. Phosphate based-superparamagnetic hydroxyapatite, used to support BiOCl in this work, was believed to be applicable for resolving the recycling problem of other metal-containing catalyst.Keywords:bromate;carboxyl anion radical;reduction;magnetic recovering
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Yifei Zhang,Zhechao Hua,Xuewen Zhang,Kaiheng Guo,Jingyun Fang
Solar photolysis of free chlorine (solar/chlorine) in bromide-containing water occurs under various scenarios, such as chlorinated reservoirs and outdoor swimming pools, and the formation of chlorate and bromate is an important issue in the system. We reported unexpected trends for the formation of chlorate and bromate in the solar/chlorine system. Excess chlorine inhibited the formation of bromate, i.e., increasing chlorine dosages from 50 to 100 μM reduced the bromate yield from 6.4 to 1.2 μM in solar/chlorine at 50 μM bromide and pH 7. The yield of bromate in solar/chlorine at 100 μM chlorine and 50 μM bromide in 240 min was 18.8% of that at 50 μM bromine only. The underlying mechanism was that HOCl can react with bromite (BrO 2 − ) to form HOClOBrO − , whose multi-step transformation finally formed chlorate as the major product and bromate as the minor product. This reaction overwhelmed the oxidation of bromite to form bromate by reactive species, such as • OH, BrO • and ozone. On the other hand, the presence of bromide greatly enhanced the formation of chlorate. Increasing bromide concentrations from 0 to 50 μM enhanced the chlorate yields from 2.2 to 7.0 μM at 100 μM chlorine. The absorbance of bromine was higher than that of chlorine, thus the photolysis of bromine formed higher levels of bromite at higher bromide concentrations. Then, bromite rapidly reacted with HOCl to form HOClOBrO − and it further transformed to chlorate. Additionally, 1 mg L − 1 NOM had a negligible effect on bromate yields in solar/chlorine at 50 μM bromide, 100 μM chlorine and pH 7. This study demonstrated a new pathway of chlorate and bromate formation in the solar/chlorine system with bromide.
研究领域:
环境科学
·
化学
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产品关联
DOI
PubMed
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Qian-Yuan Wu,Lu-Lin Yang,Xin-Yang Zhang,Wen-Long Wang,Yao Lu,Ye Du,Yun Lu,Hong-Ying Hu
Ammonia (NH4+) and hydrogen peroxide (H2O2) have been widely used to inhibit bromate formation during ozonation. However, organic byproducts can also pose a risk under these conditions. During bromate inhibition, the influence of NH4+ and H2O2 on organic byproducts and their toxicity should be elucidated. Our study found that NH4+ suppressed organic bromine, but might result in increased toxicity. Adding 0.5 mg/L of NH4+–N substantially increased both the formation of cytotoxicity and genotoxicity (DNA double-strand breaks) of organic byproducts from 0.6 to 1.6 mg-phenol/L, and from 0.3 to 0.8 μg-4-NQO/L (0.5 mg/L Br–, 5 mg/L O3). NH4+ decreased bromate, but increased the overall toxicity of the integrated byproducts (organic byproducts and bromate). Organic nitrogen measurements and 15N isotope analysis showed enhanced incorporation of nitrogen into organic matter when NH4+ and Br– coexisted during ozonation. NH4+ decreased the formation of brominated acetonitriles, but enhanced the formation of brominated nitromethanes and brominated acetamides. These brominated nitrogenous byproducts were partially responsible for this increase in toxicity. Different from ammonia, H2O2 could reduce both bromate and the toxicity of organic byproducts. In the presence of 0.5 mg/L Br– and 10 mg/L O3, adding H2O2 (0.5 mM) substantially suppressed bromate, cytotoxicity formation and genotoxicity formation by 88%, 63% and 67%. This study highlights that focusing on bromate control with NH4+ addition might result in higher toxicity. Efforts are needed to effectively control the toxicities of bromate and organic byproducts simultaneously.
研究领域:
环境科学
·
毒理学
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产品关联
DOI
PubMed
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Shiguan Xu,Lijun Yan,Hui Cheng,Hui Xie,Lina Zeng,Lin Li,Shuhai He,Wei Sun
In this paper an electrochemical sensor was fabricated by dropping a graphdiyne (GDY) and hemin suspension solution on the surface of carbon ionic liquid electrode (CILE) followed by casting the Nafion film (Nafion/hemin-GDY/CILE). The morphology of GDY was observed by scanning electron microscopy with the biomolecular structure of hemin-GDY and hemin characterized by UV-Vis absorption spectrophotometry, which proved that hemin maintained the original structure after mixing with GDY. Direct electrochemistry of hemin on the GDY modified electrode was realized with a pair of well-defined redox peaks and electrochemical performances were checked in detail with the electrochemical parameters calculated. Nafion/hemin-GDY/CILE showed excellent electrocatalytic ability towards the reduction of bromate with the detection range from 5.00 to 50.0 mmol L -1 and the detection limit of 3.3 mmol L -1 (3 σ ). In addition, the modified electrode possessed good reproducibility and stability, which was applied to the analysis of seawater samples.
研究领域:
分析化学
·
电化学传感器
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DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 32
·23011-23022
·
IF 3.9
Ying Xu,Shuili Yu,Cong Huang,Zheng Xu
The photo-reduction of bromate (BrO3−) has attracted much attention due to the carcinogenesis and genotoxicity of BrO3− in drinking water. In this study, a heterojunction photocatalyst was developed by depositing Au nanoparticles (NPs) onto P25 TiO2 NPs through a one-pot, solvent-thermal process. Due to the unique properties of Au, the Au NPs deposited on the TiO2 surface created a Schottky barrier between the metal and the semiconductor, leading to an effective separation of photo-generated charge carriers as the Au nanoparticles served as electron sinks. The Au/TiO2 photocatalyst demonstrated efficient reduction of BrO3− under UV light illumination without the need for sacrificial agents. The effect of different Au loading of Au/TiO2 was systematically investigated for its influence on the generation of electrons and the reduction ability of BrO3−. The results indicate that the 1% Au/TiO2 catalyst exhibited a higher concentration of localized electrons, rendering it more effective in BrO3− removal. The photocatalytic efficiency for BrO3− reduction decreased upon the addition of K2S2O8 as an electron quencher, suggesting that the primary factor in this photo-reduction process was the availability of electrons. These findings hold promise for the potential application of the Au/TiO2 catalyst in the removal of BrO3− from drinking water through photo-reduction.
研究领域:
环境科学
·
材料科学
·
饮用水处理
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Xixi Chen,Hai Yang,Chaktong Au,Shuanghong Tian,Ya Xiong,Yu Chang
Reduction of potential carcinogenic bromate formation is a big challenge for the application of ozone in the treatment of Br − -containing wastewater. Three CeO 2 nanocrystals individually with exposed (1 0 0), (1 1 0), and (1 1 1) facets were prepared and adopted as catalysts for the ozonation of Br − containing wastewater. It is found that faceted CeO 2 greatly inhibited the bromate formation and simultaneously enhanced the pollutant removal. The catalytic activity follows the order of (1 0 0) > (1 1 0) > (1 1 1). In the presence of CeO 2 (1 0 0), there is 71.4 ± 2.9% of sulfamethoxazole (SMZ) degradation (only 24.9 ± 1.8% in ozone alone). Moreover, the generation of bromate was reduced by 29.6%, 38.8%, 52.4%, 66.4%, respectively, when the initial Br − concentration is 1.0, 2.0, 34.0, 65.0 mg L −1 . Meanwhile, the antibacterial-active groups in most of the identified intermediates were destroyed and much lower biotoxicity of the treated wastewater is observed. The good reducibility and Lewis acidity of CeO 2 (1 0 0) favors the activation of ozone and the redox cycle of ceria. DFT calculations show that ozone facilely dissociates into surface O and O 2 through interaction with the (1 0 0) facet. It is demonstrated that O 2 − , its derivatives (i.e. OH and 1 O 2 ) and surface O are generated and get involved in SMZ degradation. It is noted that O 2 − also functions as a key reductant to convert Ce 4+ to Ce 3+ which reduce HBrO/BrO − and BrO 3 − to Br − and therefore inhibit the formation of bromate. These results indicate that CeO 2 (1 0 0) catalyzed ozonation is a promising advanced oxidation process for the treatment of Br-containing wastewater, and crystal facet engineering is an efficient strategy to enhance the catalytic performance.
研究领域:
环境科学
·
催化化学
·
理论计算
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2021
·
IF 5.909
Shasha Tang,Jie Yao,Hongyuan Liu,Yan Zhang
Although considered as a promising candidate for photocatalytic bromate reduction, TiO 2 is restricted by its fast recombination of photo-induced charge carriers. In this paper, a series of efficient photocatalysts (TiO 2 /TC) were prepared by coupling commercial titania (P25) with titanium carbide MXene (Ti 3 C 2 ) via a simple hydrothermal method, where Ti 3 C 2 was utilized as a noble-metal-free cocatalyst. Batch experiments of photocatalytic bromate removal by TiO 2 /TC composites were conducted under UV irradiation. Its performance and mechanism were also investigated. The results showed that more than 95% of bromate could be removed by TiO 2 /TC-1 composite (Ti 3 C 2 and P25 in a mass ratio of 1%) in 15 min, and its removal rate was 4.87 times higher than that of pure P25. The photocatalytic reduction of bromate by TiO 2 /TC was an interfacial reaction, and bromide was the main product. The greatly improved activity of TiO 2 /TC composites was attributed to the improved separation efficiency of photogenerated charge carriers and narrower band gap. TiO 2 /TC-1 composite exhibited a longer lifetime (6.05 ns) of electron-hole pairs than pristine P25 (4.31 ns). Moreover, due to its excellent electrical conductivity, Ti 3 C 2 functioned as “an electron sink” to accumulate photoinduced electrons from the excited P25. And the Schottky barrier formed in the tight Ti 3 C 2 -P25 interface provided a unidirectional channel for electron transfer , facilitating the separation of electron-hole pairs. In addition, TiO 2 /TC-1 composite had a good stability in bromate removal. This work highlights the potential of Ti 3 C 2 as a noble-metal-free photocatalytic cocatalyst and explores the possible expansion of the application of MXene.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Ying Xu,Zhiwen He,Shuili Yu,Lei Li,Luyang Cai,Peng Yi
Recently, the heterogeneous advanced reduction processes (ARPs) for bromate (BrO 3 - ) degradation have attracted considerable attention due to its stable performance and easy combination with UV disinfection. In this study, a UV/TiO 2 -Bi advanced reduction process (ARP) was established for BrO 3 - removal without adding external sacrificial agents. In the UV/TiO 2 -Bi ARP, Bi nanoparticles (NPs) doped on the TiO 2 acted as hole trapping centers, while TiO 2 NPs were used as reduction centers for the reduction of BrO 3 - , which enhanced the charge carrier separation. The UV/TiO 2 -Bi-1% ARP exhibited the highest BrO 3 - removal rate without the addition of sacrificial agents in the reaction solution compared to UV/TiO 2 ARP and the UV/TiO 2 -Bi ARP at other Bi/Ti ratios. The result of 72% removal of 200 µg/L BrO 3 - at 60 min by 0.2 g/L TiO 2 -Bi-1% in tap water at pH 6.8 and 7.71 mg/L dissolved oxygen (DO) demonstrates the promising potential of the UV/TiO 2 -Bi ARP for the removal of BrO 3 - in practical applications. Compared to the 99.5% removal in deionized (DI) water at 60 min, lower BrO 3 - reduction in tap water was likely attributed to the consumption of photo-generated electrons by NO 3 – and the adsorption of natural organic matter on the surface of TiO 2 -Bi-1% nanocomposites. The study provides not only a novel BrO 3 - removal system with good photo-reduction performance, but also some guidance for the influence of constituents in raw water on the treatment of BrO 3 - .
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）