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
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医学检验
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2023
·
IF 2.6
Shuyang Shi,Baozhong Ma,Shuang Shao,Yongqiang Chen,Chengyan Wang
An original technology named HNO3 pressure leaching has been proposed by our team to leach Al from coal gangue and fly ash. Although the preliminary separation of Al and Fe had been achieved during leaching, a small amount of Fe impurity was still unavoidably dissolved into the leach liquor. To obtain pure Al2O3 during subsequent pyrolysis, it is imperative to synchronously remove Fe3+ during the crystallization of Al(NO3)3·9H2O. Herein, the phase equilibria of the Al(NO3)3–Fe(NO3)3–H2O(−HNO3) system at 25–40 °C and 0–8.12 mol kg–1 of HNO3 molality were investigated. The results indicated that the ternary system was a simple cosaturated type consisting of an immutable point, two univariate curves, and two crystallization regions. Notably, the solubility and crystallization region of Al(NO3)3·9H2O were barely impacted by acidity, while the opposite was true for Fe(NO3)3·9H2O. This finding was instructive for the crystallization of Fe(NO3)3·9H2O from the liquor with high Fe and low Al. Moreover, a high crystallization yield could be obtained at low temperatures. Finally, an appropriate crystallization procedure was provided. This study is expected to provide basic data and theoretical support for the crystallization and separation of mixed nitrates containing Al and Fe.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
HYDROMETALLURGY
·
2020
·
IF 3.338
Shaohua Wu,Wenju Tao,Yanchen Zheng,Youjian Yang,Jiangyu Yu,Jingbo Cui,Yu Lu,Zhongning Shi,Zhaowen Wang
A hydrometallurgical process was developed to extract lithium from a spent lithium-containing aluminum electrolyte, reduce the stacking of spent aluminum electrolyte, and recover the valuable elements. In this study, we extracted lithium from an electrolyte using the following three steps: 1) leaching with HNO 3 − Al(NO 3 ) 3 , 2) neutralizing the leachate obtained in the first step, and 3) precipitating the lithium carbonate. A lithium extraction efficiency of 88.0% could be achieved after a leaching time of 6 h, at a leaching temperature of 80 °C and an Al/F molar ratio of 1:6. During the process of neutralization, Al 3+ and F − was precipitated as Al 2 ((OH) 0.46 F 0.54 ) 6 (H 2 O). The obtained Li 2 CO 3 with a high purity of 98.8%.
研究领域:
冶金学
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材料科学
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环境工程
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DOI
高影响因子
Nanomaterials
·
2025
·Vol. 15
·期 14
·1094
·
IF 4.3
Chuang Zhu,Wenxuan He,Manting Gu,Dan Zhang,Baiyuan Tian
LiNO3-NaNO3-KNO3-NaNO2has a relatively low phase-change temperature, making it suitable for low-temperature heat utilization systems. This study focuses on the performance optimization of the quaternary molten salt to advance its applicability. A series of nanocomposites consisting of nano-SiO2/MgO and the quaternary salt are prepared. Core thermophysical properties, including phase transition behaviors and thermal transport parameters, are quantified. The incorporation of nano-SiO2/MgO induces moderate adjustments to the melting point and latent heat yet demonstrates an obvious enhancement in specific heat capacity. Optimal doping at 0.7 wt.% SiO2and 0.3 wt.% MgO yields a molten-state specific heat of 1.51 J/(g·K), representing a 6% increase over the undoped base salt (1.42 J/(g·K)). By combining the thermal diffusivity properties of the samples, this study found that the doping of nanoparticles typically induces new structures in molten salts that tend to enhance the specific heat capacity while simultaneously reducing thermal diffusivity.
研究领域:
储能
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纳米材料
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热工工程
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材料科学
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DOI
PubMed
高影响因子
CHEMOSPHERE
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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
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水污染控制
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光化学反应
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2021
·
IF 3.178
Shijue Wang,Ju Xiao,Fei Yuan,Long Li,Yafei Guo,Yingchun Xie,Tianlong Deng
In order to separate cesium nitrate from the eluant mixture sodium nitrate solution, the phase equilibrium of the ternary system (NaNO 3 + CsNO 3 + H 2 O) at 338.15 K and 0.1 MPa was investigated using the isothermal equilibrium solution method, and the solubilities and physicochemical properties (density and refractive index) of the system were determined, experimentally. According to the experimental data, the phase diagram and physicochemical properties versus the composition diagram of the ternary system at 338.15 K were established for the first time. There is one invariant point (NaNO 3 + CsNO 3 ), two univariant curves, and two crystallizing regions corresponding to NaNO 3 and CsNO 3 . The phase diagram belongs to a simple-type ternary system, and neither double salt nor solid solution was formed. Based on the phase diagrams of this system at 298.15 and 338.15 K, the cycle separation process for CsNO 3 recovery from the eluant of sodium nitrate mixture solution was evolved. It is worth noting that 90.29 % CsNO 3 can be separated from the mixed solution after three cycles. It is significant for the green recovery of cesium nitrate from the eluent solution containing sodium nitrate effectively.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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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
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电化学工程
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DOI
高影响因子
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
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生物地球化学
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DOI
PubMed
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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DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Zhan-Ping Qiao,Meng-Yao Su,Yuan-Lin Dang,Qi-Chao Yang
The phase diagrams of the Mg(NO 3 ) 2 –Ln(NO 3 ) 3 (Ln = Nd, Sm, Eu, Tb)–HNO 3 –H 2 O systems in the (∼20%) HNO 3 regions at T = 298.15 K were determined by using an isothermal solution saturation method. The Schreinemaker’s wet residues method was used to determine the compositions of solid-phases. Both Mg(NO 3 ) 2 –Nd(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Sm(NO 3 ) 3 –HNO 3 –H 2 O systems are complicated with three equilibrium solid phases Mg(NO 3 ) 2 ·6H 2 O, Mg 3 Ln 2 (NO 3 ) 12 ·24H 2 O and Ln(NO 3 ) 3 ·6H 2 O (Ln = Nd, Sm). But the systems Mg(NO 3 ) 2 –Eu(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Tb(NO 3 ) 3 Tb–HNO 3 –H 2 O are simple eutonic type. The two new solid-phase compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O are congruently soluble in an average medium of ∼20 mass % HNO 3 , and they were identified and characterized by the methods of powder X-ray diffraction, X–ray diffraction single crystal structure analysis, and thermogravimetric/differential thermogravimetric. The XRD diffraction patterns for the two new solid-phase compounds are identical due to their isomorphic structure. They belong to hexagonal systems, with space group R 3 . For Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O, a = b = (1.0993 ± 0.0005) nm, c = (1.7211 ± 0.0007) nm, V = (1.8012 ± 0.0013) nm 3 , D c = (4.2532 ± 0.0024) g·cm −3 , Z = 3; for Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O, ( a = b = 1.1198 ± 0.0004) nm, c = (1.7257 ± 0.0006) nm, V = (1.8742 ± 0.0011) nm 3 , D c = (4.1201 ± 0.0012) g cm −3 , Z = 3. The standard molar enthalpies of solution of the compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O in water (aq) were measured to be (101.26 ± 0.77) kJ mol −1 and (80.27 ± 0.81) kJ mol −1 , and their standard molar enthalpies of formation were calculated to be – (12214.13 ± 2.5) kJ mol −1 and – (12183.6 ± 2.5) kJ mol −1 , respectively.
研究领域:
化学
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物理化学
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材料科学
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DOI
高影响因子
Electronic Materials Letters
·
2015
·Vol. 11
·期 4
·702-706
·
IF 1.98
Han Wen-Song
In this manuscript, the third-generation hyperbranched polyester was synthesized with 2, 2-dimethylol propionic acid as AB 2 monomer and pentaerythrite as core molecule by using step by step polymerization process at first. Then, the Cu-Ag particles were prepared by co-reduction of silver nitrate and copper nitrate with ascorbic acid in the aqueous solution using hyperbranched polyester as template. Finally, the Cu-Ag@Ag particles were prepared by coating silver on the surface of Cu-Ag particles by reduction of silver nitrate. The synthesized hyperbranched polyester and Cu-Ag@Ag particles were characterized by Fourier transform infrared (FT-IR) spectroscopy, UV-vis spectra, x-ray diffraction, Laser light scattering, thermogravimetric analysis (TGA) and SEM. UV-vis spectra results showed that the Cu-Ag@Ag particles had a strong absorption band at around 420 nm. Laser light scattering and SEM studies confirmed that the most frequent particle sizes of Cu-Ag@Ag particles were 1.2 um. TGA results indicated that the Cu-Ag@Ag particles had good thermal stability.
研究领域:
材料科学
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化学工程
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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
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）