ANALYTICAL CHEMISTRY
·
2020
·
IF 6.785
Bo Wang,Shuai Zheng,Yan Huang,Ying Wang,Zhenyu Zhu,Ran Ma,Yu Zhao,Xijie Yin,Jing Su,Juan Xiong,Benli Zhang,Youping Zhou
The 18O/16O (and 15N/14N) ratio of natural nitrate (NO3–) and nitrite (NO2–) can be used to extract valuable information about their source and fate as environmental contaminants, their metabolism as macronutrients in plants and animals, and their behavior in the N biogeochemical cycle. We developed an accurate, precise, sensitive (minimum sample size: 0.2 μg NO3–-equivalent), and reliable (minimal oxygen exchange, loss, or gain) method to selectively isolate and purify nitrate and nitrite from natural water, soil, air, and plant materials by strong anion exchange (SAX) for low- to normal-salinity samples or strong cation exchange (SCX) for high-salinity samples, followed by quantitative conversion to their respective benzyl esters, which can be separated and individually analyzed for δ18O (and potentially δ15N) by gas chromatography (GC)/pyrolysis/GC/isotope-ratio mass spectrometry (IRMS). The method compares favorably with the currently popular bacterial denitrification and chemical reduction methods, in terms of sensitivity and reliability, and has the potential to simultaneously measure δ15N and δ18O of nitrate and nitrite from natural samples of various origins.
研究领域:
环境科学
·
生物地球化学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Jing Xu,Heng Zhang,Tao Luo,Zizheng Liu,Jun Xia,Xiang Zhang
The effects of co-existing nitrogen species in surface water on the phototransformation of organoarsenical p -arsanilic acid ( p -ASA) have been investigated using a xenon lamp as a simulated solar light source. Significant enhancements of p -ASA phototransformation efficiency were observed in the presence of nitrate and nitrite, increasing with the concentration of these species and pH, whereas ammonia showed no obvious effect. The products, including inorganic arsenic species and organic derivatives, have been analyzed in order to reveal the phototransformation pathways. In the nitrate and nitrite systems, only small proportions of inorganic arsenic species were generated, with the majority of p -ASA being converted into other organoarsenical derivatives through hydroxylation, nitration, and nitrosation. Phototransformation of p -ASA in collected natural surface water was also observed. This work has implications for the phototransformation of p -ASA in nitrogen-contaminated surface water.
研究领域:
环境科学
·
水污染控制
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光化学反应
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Qinan Song,Miao Li,Jiacheng Li,Shuo Zhang,Lei Yang,Xiaoyu Chen,Fanbin Meng,Xiang Liu
The use of biological and chemical methods for the simultaneous removal of inorganic nitrogen compounds containing nitrate, ammonia, and nitrite in groundwater typically cannot achieve synchronous oxidation and reduction in an undivided reactor. In the present study, with the strict regulation of the oxidation reaction in the anode zone and reduction reaction in the cathode zone, simultaneous removal of nitrate, ammonia, and nitrite was achieved in an undivided electrochemical system. Our results indicated that ammonia and nitrite had been completely removed, and the concentration of nitrate was reduced to 8.58 mg N/L with initial nitrate, ammonia, and nitrite concentrations of 50.00, 10.00 and 5.00 mg N/L, respectively. Cyclic voltammetry (CV) and potentiostatic electrolysis revealed that the electrode surface reaction process, that is, nitrate, ammonia, and nitrite in the system, could be converted into nitrogen via ClO − generated from Cl − produced from the electrochlorination process during multiple cycle attenuation. Moreover, both CV and Density functional theory (DFT) calculations revealed the inhibitory effect of coexisting ammonia and nitrite on the electrochemical reduction of nitrate on the Cu cathode. This strategy opens a paradigm for the simultaneous efficient electrocatalytic removal of nitrate, nitrite, and ammonia in an undivided single reactor.
研究领域:
环境科学
·
电化学工程
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Huiling Du,Jingwen Wang,Pengchao Xie,Yong Liu
S(IV)-based advanced reduction processes have been viewed as effective strategies to eliminate nitrate (NO 3 − ) from water. In this work, CaSO 3 was introduced as the slow-release source of S(IV), and the combination of UV and CaSO 3 was applied for NO 3 − reduction. 30 mg N/L of NO 3 − could be removed in the UV/CaSO 3 process after 60 min reaction; UV irradiation and hydrated electrons ( e aq − ) reduction were responsible for the NO 3 − removal. The generated nitrite (NO 2 − ) could further be removed in this process (UV/CaSO 3 ). The degradation of NO 3 − increased from 65.8% to 100% with elevating CaSO 3 dosage from 0.2 to 2 g/L, and the accumulation of NO 2 − decreased accordingly. Almost 100% removal of NO 3 − was achieved with initial pH being 3–12 without NO 2 − accumulation after reaction. The effects of anions (Cl − , CO 3 2− , and SO 4 2− ) on the NO 3 − degradation and NO 2 − accumulation in UV/CaSO 3 were negligible. Nitrogen (N 2 ) was demonstrated as the major gaseous product during the NO 3 − reduction, and nitrogen-sulfur compounds (not NO 2 − or NH 4 + ) remained the final liquid reduction products of NO 3 − . This study revealed that UV/CaSO 3 would be a promising approach to remove NO 3 − chemically and simultaneously control the NO 2 − accumulation.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Jin Li,Yuan Wang,Xiujing Xing,Yang Wang,Wei Xiong,Hao Li
Electrochemical Nitrate Reduction (NO 3 − RR) is a promising green process for producing ammonia and treating waste water. The nitrate-to-ammonia reduction involves multi-step electron/proton-transfer processes, where the NO 3 − →NO 2 − step may serve as the rate-determining step, posing a critical bottleneck for efficient NH 3 synthesis. In this paper, the emulsion hydrothermal method is used to synthesize spherical and nanoflower-like CuO/CuCo 2 O 4 catalysts with small particle stacking. Among them, CuCo 2 O 4 perfectly inherits the advantages of CuO and Co 3 O 4 , and successfully connects the two-step reactions of NO 3 − →NO 2 − and NO 2 − →NH 3 in series. The CuO formed by excess copper doping is reduced to monomeric copper during electrolysis. Cu is able to synergize with CuCo 2 O 4 to break through the bottleneck of the rate-limiting step of NO 3 − →NO 2 − , exhibiting almost the same ammonia production efficiency in both NO 3 − RR and nitrite reduction reaction (NO 2 − RR). The NH 3 yield of Cu/CuCo 2 O 4 at −0.70 V (vs RHE) reached a maximum of 24.58 mg h −1 mg cat −1 under neutral electrolyte conditions and exhibited 100% Faraday efficiency for NH 3 . Under the same conditions (where the reaction substrate is NO 2 − ), Cu/CuCo 2 O 4 reached an NH 3 yield of 24.34 mg h −1 mg cat −1 in NO 2 − RR.
研究领域:
电化学
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催化
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环境工程
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材料科学
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绿色化学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2023
·
IF 11.4
Qing Cao,Biwu Chu,Peng Zhang,Qingxin Ma,Jinzhu Ma,Yuan Liu,Jun Liu,Yaqi Zhao,Hong Zhang,Yonghong Wang,Hong He
Nitrate photolysis is a vital process in secondary NOx release into the atmosphere. The heterogeneous oxidation of SO2 due to nitrate photolysis has been widely reported, while the influence of SO2 on nitrate photolysis has rarely been investigated. In this study, the photolysis of nitrate on different substrates was investigated in the absence and presence of SO2. In the photolysis of NH4NO3 on the membrane without mineral oxides, NO, NO2, HONO, and NH3 decreased by 17.1, 6.0, 12.6, and 57.1% due to the presence of SO2, respectively. In the photolysis of NH4NO3 on the surface of mineral oxides, SO2 also exhibited an inhibitory effect on the production of NOx, HONO, and NH3 due to its reducibility and acidic products, while the increase in surface acidity due to the accumulation of abundant sulfate on TiO2 and MgO promoted the release of HONO. On the photoactive oxide TiO2, HSO3–, generated by the uptake of SO2, could compete for holes with nitrate to block nitrate photolysis. This study highlights the interaction between the heterogeneous oxidation of SO2 and nitrate photolysis and provides a new perspective on how SO2 affects the photolysis of nitrate absorbed on the photoactive oxides.
研究领域:
大气化学
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环境科学
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DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2024
·
IF 3.9
Shanshan Chen,Zhiwei Wang,Quan Zhang,Shiming Qiu,Yifan Liu,Guangzhi Hu,Jun Luo,Xijun Liu
Graphical Cu-based compound containing Cu 3 N is synthesized through a simple one-step pyrolysis method, applied it to electrocatalytic NO 3 RR, and tested the performance of the Zn-NO 3 − battery. The Cu 3 N exhibits NH 3 yield of 173.7 μmol h −1 cm −2 , with FE NH3 reaching 91.0 % at −0.3 V vs . RHE, which assembles a Zn-NO 3 − battery. Nitrate reduction reaction (NO 3 RR) involves an 8-electron transfer process and competes with the hydrogen evolution reaction process, resulting in lower yields and Faraday efficiency (FE) in the process of NH 3 synthesis. Especially, Cu-based catalysts (Cu 0 and Cu + ) have been investigated in the field of NO 3 RR due to the energy levels of d -orbital and the least unoccupied molecular orbital (LUMO) π * of nitrate's orbital. Based on the above, we synthesized a Cu-based compound containing Cu 3 N (Cu + ) through a simple one-step pyrolysis method, applied it to electrocatalytic NO 3 RR, and tested the performance of the Zn-NO 3 − battery. Through various characterization analyses, Cu-based catalysts (Cu + ) are the key active sites in reduction reactions, making Cu 3 N a potential catalyst for ammonia synthesis. The research results indicate the application of Cu 3 N catalyst in NO 3 RR shows the best NH 3 yield of 173.7 μmol h −1 cm −2 with FE NH3 reaching 91.0 % at −0.3 V vs . RHE, which is much higher than that of Cu catalyst without N. In addition, the Zn-NO 3 − battery based on Cu 3 N electrode also exhibits an NH 3 yield of 39.8 μmol h −1 cm −2 63.0 % FE NH3 , and a power density of 2.7 mW cm −2 as well as stable cycling charge-discharge stability for 5 hours. This work guides the application of Cu 3 N enhanced regulation of the active site in the electrocatalytic synthesis of NH 3 from NO 3 RR.
研究领域:
材料科学
·
电化学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Xuguang Liu,Fengqin Chang,Dayu Zhang,Meijie Ren
This study investigated the influence of nitrate/nitrite on the degradation and transformation pathway of triclosan (TCS) in UV, UV/peracetic acid (PAA) and UV/HClO processes. The results indicated that the function of nitrate/nitrite significantly depended on the UV source and wavelength, especially nitrate. Generally, the presence of nitrate decreased the direct photo-degradation of TCS in the UV based disinfection. In the LED-UV and LED-UV/HClO processes, the presence of nitrate improved the radical oxidation, and transformation pathway of TCS was varied accordingly. However, nitrate more played a role of photo-competitor in the UV/PAA process, and the reactive nitrogen species (RNS) was difficult to participant in the degradation of TCS due to low redox potential . Compared to nitrate, the presence of nitrite decreased the degradation of TCS in three different UV based disinfection processes. Under UV irradiation, nitrite primarily acted as an irradiation competitor and radical scavenger. Thus, the indirect photo-degradation of TCS was reduced. Noticeably, nitrate/nitrite were the improtant precersors of nitrogenous products in the UV base disinfection. Many new nitrogenous products were identified. But RNS preferentially reacted with the intermediates by –NO 2 addition compared to directly reacted with TCS.
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 CHROMATOGRAPHIC SCIENCE
·
2015
·Vol. 53
·期 7
·1169-1177
·
IF 1.363
Zhao Jiao,Wang Jun,Yang Yaling,Lu Yunhui
A simple efficient and practical separation/preconcentration coupled with HPLC method for the determination nitrate and low concentrations of nitrite in human urine and blood was investigated. The method is based on precolumn derivatization using the Griess reaction and cloud-point extraction (CPE) of nitrite anion and direct determination of nitrate using its UV absorbance by ion-pair HPLC. The chromatographic process with detection at two wavelengths (510 and 220 nm) allows the determination of nitrite and nitrate. Decolorization and protein precipitation of urine and blood was applied to overcome the interference of matrix and enhance the sensitivity. The method was validated for linearity, accuracy and precision. Under the optimum conditions, the linear range of nitrite from 10 to 1,000 ng/mL and nitrate from 0.1 to 10 µg/mL. Product recoveries ranged from 92.4 to 99.9%. The limits of detection were 1 ng/mL and 0.1 µg/mL for nitrite and nitrate, respectively. Therefore, the technique was simple and reliable, with potential application in biological sample analysis of nitrate and nitrite.
研究领域:
分析化学
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生物医学
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产品关联
DOI
PubMed
高影响因子
CHROMATOGRAPHIA
·
2013
·Vol. 76
·期 23
·1649-1655
·
IF 1.437
Wu Anguo,Duan Tingting,Tang Dan,Xu Youhua,Feng Liang,Zheng Zhaoguang,Zhu Jiaxiao,Wang Rushang,Zhu Quan
Nitrite and nitrate are main stable products of nitric oxide, a pivotal cellular signaling molecule, in biological fluids. Therefore, accurate measurement of the two ions is profoundly important. Nitrite is difficult to be determined for a larger number of interferences and unstable in the presence of oxygen. In this paper, a simple, cost-effective and accurate HPLC method for the determination of nitrite and nitrate was developed. On the basis of the reaction that nitrite is oxidized rapidly to nitrate with the addition of acidic potassium permanganate, the determination of nitrite and nitrate was achieved by the following strategy: each sample was injected twice for HPLC analysis, i.e. the first injection was to measure nitrate, and the second injection was to measure total nitrate including initial nitrate and the nitrate from the conversion of nitrite with the addition of acid potassium permanganate in the sample. The amount of nitrite can be calculated as difference between injections 2 and 1. The HPLC separation was performed on a reversed phase C 18 column for 15 min. The mobile phase consisted of methanol–water (2:98 by volume); the water in the mobile phase contained 0.60 mM phosphate salt (potassium dihydrogen and disodium hydrogen phosphate) and 2.5 mM tetrabutylammonium perchlorate (TBAP). The UV wavelength was set at 210 nm. Additionally, we systemically investigated the effects of the concentration of phosphate salt and TBAP in the mobile phase, the pH of the mobile phase, and the amount of acidic potassium permanganate added to the sample on the separation efficacy. The results showed that the limits of detection (LOD) and the limit of quantitation (LOQ) were 0.075 and 0.25 μM for nitrate (containing the oxidized nitrite), respectively. The linear range was 1–800 μM. This developed approach was successfully applied to assay nitrite/nitrate levels in cell culture medium, cell lysate, rat plasma and urine.
研究领域:
生物化学
·
医学检验
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2021
·
IF 9.028
Baiyang Chen,Yuanxi Huang,Qi Zhang,Dionysios D. Dionysiou,Lei Wang,Juan Li
Photolysis via vacuum ultraviolet (VUV) irradiation is a robust technology capable of inactivating pathogens and degrading micropollutants, and therefore, its application has recently attracted great interest. However, VUV irradiation of water may yield nitrite (NO2–, a regulated carcinogenic contaminant) and hydrogen peroxide (H2O2, a compound linked to aging, inflammation, and cancer), thus motivating us to better understand its risks. By applying a novel H2O2 detection method insensitive to coexisting compounds, this study clearly observed concurrent and substantial formations of NO2– and H2O2 during VUV irradiation of various synthetic and real waters. Increasing pH and/or decreasing oxygen promoted the conversion of nitrate (NO3–) into NO2– but suppressed the H2O2 formation, suggesting that there was a transition of radicals from oxidizing species like hydroxyl radicals to reducing species like hydrogen atoms and hydrated electrons. Under low light dose conditions, both NO2– and H2O2 were formed concurrently; however, under high radiation dosage conditions, the patterns conducive to NO2– formation were opposite to those conducive to H2O2 formation. Real water irradiation proved the formation of NO2– and H2O2 at levels near to or greater than current drinking water regulatory limits. Hence, the study reminds of a holistic view of benefits and disbenefits of a VUV process.
研究领域:
环境科学
·
公共卫生
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DOI
PubMed
高影响因子
Small
·
2022
·Vol. 18
·期 21
·2200436
·
IF 15.153
Fengling Zhou,Chenghua Sun
The fuel cell is a basic device to generate electricity from chemical fuels. It is often operated with oxygen as the oxidizing agent, but its sluggish reduction has become a key challenge. Herein, a conceptual oxygen-free design is demonstrated, namely a zinc-nitrate fuel cell, which converts nitrate waste into valuable ammonia and generates electricity simultaneously. The cell is constructed with zinc foil as the anode and ruthenium (Ru) nanoparticles loaded on nickel foam as the cathode. Catalyzed by Ru/Ni hydroxide hybrid, the reaction rate of 384 mmol h –1 mg Ru –1 (1.4 × 10 –6 ± 0.1 × 10 –6 mol s –1 cm –2 ) and Faradic efficiency (FE NH3 = 97% ± 2%) at −0.6 V versus reverse hydrogen electrode are achieved for nitrate-to-ammonia conversion. During ammonia production, such zinc-nitrate fuel cell can further deliver a maximum power density of 51.5 mW cm –2 (0.25 cm 2 electrode) and 23.3 mW cm –2 (1 cm 2 electrode), keeping ultrahigh Faradic efficiency (97% ± 4% at 40 mA cm –2 ) after long tests.
研究领域:
环境科学
·
电化学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）