Journal of Nanomaterials
·
2014
·
IF 1.611
Jiancheng Wang,Zhaoliang Peng,Bing Wang,Lina Han,Liping Chang,Weiren Bao,Gang Feng
A series of manganese salts (Mn(NO3)2, MnCl2, MnSO4, and Mn(Ac)2) and silicon materials (silica sand, silica sol, and tetraethyl orthosilicate) were used to synthesize Mn/Si complexes in supercritical water using a tube reactor. X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were employed to characterize the structure and morphology of the solid products. It was found that MnO2, Mn2O3, and Mn2SiO4 could be obtained in supercritical water at 673 K in 5 minutes. The roles of both anions of manganese salts and silicon species in the formation of manganese silicon complexes were discussed. The inorganic manganese salt with the oxyacid radical could be easily decomposed to produce MnO2/SiO2 and Mn2O3/SiO2. It is interesting to found that Mn(Ac)2 can react with various types of silicon to produce Mn2SiO4. The hydroxyl groups of the SiO2 surface from different silicon sources enhance the reactivity of SiO2.
研究领域:
化学
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材料科学
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DOI
高影响因子
Advanced Optical Materials
·
2024
·Vol. 12
·期 34
·2401591
·
IF 8
Cheng Luo,Juntao Li,Ruiling Zhang,Peigeng Han,Jianyong Liu,Bin Yang
Strong Mn─Mn coupling interactions, including dipolar and exchange interactions, significantly affect the photoluminescence quantum yields (PLQYs) in Mn 2+ -based luminescent materials. However, clarifying the individual effects of dipole–dipole and exchange interactions on photoluminescence (PL) is challenging because these interactions may have similar effects on PL properties, and there is a lack of materials with precisely tunable Mn─Mn distances over a wide range. In this study, the influence of dipolar and exchange coupling on PLQY is quantitatively decoupled by designing a series of hybrid manganese chlorides single crystals with a wide tuning range of Mn─Mn distances, from 6.0 to 9.5 Å. It is found that the PLQY can be enhanced from 2.1% to 57.1%, and the PL lifetime increased from 0.21 to 3.81 ms as the Mn─Mn distance increased. This enhancement is solely attributed to the decreased energy transfer dominated by dipole–dipole interactions. At the shortest Mn─Mn distance of 6 Å, exchange coupling becomes dominant, resulting in an additional red-side PL band with negligible effects on PLQY and lifetime. This work provides valuable insights into the mechanisms underlying the regulation of PLQY in Mn 2 ⁺-based luminescent materials.
研究领域:
材料科学
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光学
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DOI
高影响因子
Materials Today Energy
·
2021
·
IF 7.311
C. Liu,X. Chi,J. Huang,Y. Liu
Development of rechargeable alkaline Zn–Mn batteries has been facing big challenges for low working voltage and poor cycling stability, although they have advantages of low cost, high safety, and simple maintenance. For the first time, this work demonstrates a record high voltage (1.78 V) for rechargeable alkaline Zn–MnO 4 − battery achieved by a high reversible redox pair of MnO 4 − /MnO 4 2− , which shows excellent cycling stability up to 1,500 cycles at a high current density of 20 mA cm −2 without obvious capacity attenuation. The MnO 4 − /MnO 4 2− redox reaction investigated by ex-situ scanning electron microscope as well as ultraviolet and visible absorption spectrum indicates high reversibility of the MnO 4 − /MnO 4 2− redox couple after the activation during the first discharge process. Furthermore, benefiting from the liquid-phase reaction nature of MnO 4 − /MnO 4 2− , a flow battery is further prototyped to show highly stable cycles with 95.8% of discharge capacity retention for 600 cycles at the current density of 40 mA cm −2 .
研究领域:
电化学
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材料科学
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DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 151
·期 4
·966-979
·
IF 2.482
Liu Qinglong,Yang Jingchao,Luo Mingsheng,Yang Zhi,Zhao Qiuna
Abstract A series of Mn–Ti oxide catalysts were synthesized by the sol–gel method and the effects of different synthesis conditions were investigated in sequence. The microstructures and properties of the catalysts were characterized by using N 2 adsorption–desorption, XRD, SEM, H 2 -TPR, NH 3 -TPD, Raman and XPS. The catalytic performance over Mn–Ti oxide catalysts prepared under different synthesis conditions for the low-temperature SCR of NO with NH 3 were also comparatively evaluated. The results reveal that the calcination temperature and metal source play a significant role in the characteristics and the SCR activities of the catalysts. A relatively low calcination temperature is beneficial to low-temperature SCR activity. Manganese nitrate or manganese acetate as the Mn source combining with tetrabutyl titanate as Ti source can achieve high SCR activities. The excellent low-temperature NH 3 -SCR activity can be ascribed to the appropriate textural properties, amorphous Mn-oxides with equal ratio of Mn 3+ /Mn 4+ , good low-temperature reducibility and abundant surface B-acid sites. Graphic Abstract
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Quanfeng Wang,Haoxuan Wei,Wenbo Liu,Jun Zhai
Forty strains of Mn-oxidizing microalgae (MnOMs) with different Mn 2+ oxidation mechanisms were identified from two aquatic environments. Among them, three strains of isolates ( Chlamydomonas sp. WH1–1, Chlamydomonas sp. WH1–4 , and Chlorella sp. WH2–5) oxidize Mn 2+ by increasing the ambient pH and by secreting Mn oxidation factors (e.g., superoxide-production enzymes and/or other Mn oxidases) into the extracellular environment at the same time. In carbamazepine (CBZ) removal by MnOMs and/or Bio-MnOx, the combination of MnOMs and Bio-MnOx significantly increased the CBZ (1 mg/L) removal efficiency from 36.05% (by MnOMs alone) and 20.11% (by Bio-MnOx alone) to 80.13% by two synergistic mechanisms. One of the synergistic mechanisms was confirmed as that the Mn 2+ was re-oxidized by MnOMs to Bio-MnOx, which can promote the CBZ removal, and another was the mutual exchange of degradation products of CBZ as shared reactants between MnOMs and Bio-MnOx. The degradation intermediates of CBZ were analyzed using high-performance liquid chromatography-tandem mass spectrometry , based on which the CBZ degradation pathway by MnOMs and Bio-MnOx was proposed. These findings expand existing knowledge on the Mn 2+ oxidation mechanisms of MnOMs, and indicate that MnOMs and their generated Bio-MnOx are promising for the removal of CBZ or other pharmaceutical contaminants from wastewater.
研究领域:
环境科学
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微生物学
·
制药工程
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分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Qiongqiong Luo,Jinshun Lei,Ziyu Zhuang,Dewen Zeng
The solubility data of the MgF2–MnF2–MnSO4–H2O quaternary system and its subsystems are crucial for the removal of magnesium ions from a MnSO4 aqueous solution as the MgF2 precipitate. However, these data recorded at 298.15 K have not been reported, except for the MnF2–MnSO4–H2O system. In this study, the solubility isotherms of the MgF2–MnF2–H2O, MgF2–MnSO4–H2O, and MgF2–MnF2–MnSO4–H2O systems at 298.15 K and MnF2 solubility in pure water at various temperatures were systematically measured. The results show that MgF2 solubility initially decreases sharply followed by a gradual decrease as the MnF2 concentration increases. MgF2 solubility rises with increasing MnSO4 concentration in pure MnSO4 and the MnF2-saturated MnSO4 aqueous solution. MgF2 solubility in the MnF2-saturated MnSO4 aqueous solution decreases to 2.3–6.5% of its value in the pure MnSO4 aqueous solution at a certain MnSO4 concentration. MnF2 solubility increases with increasing temperatures in the MnF2–H2O system. A Pitzer–Simonson–Clegg model incorporated in the ISLEC software was used to simulate and predict the solubility curves of the MgF2–MnF2–MnSO4–H2O quaternary system and its subsystems. The model satisfactorily represented the solubility data of the subbinary and subternary systems of the MgF2–MnF2–MnSO4–H2O quaternary system within the analysis error, except for the solubility isotherms of the Mg(Mn)SO4·7H2O, Mg(Mn)SO4·4H2O, and Mg(Mn)SO4·H2O solid solutions. The predicted solubility data of the MgF2–MnSO4–H2O system at 298.15 K agree well with the experimental data with a slight deviation of the MgF2–MnF2–MnSO4–H2O system. Based on the established model, the variation of MgF2 solubility curves with the addition of anhydrous MnF2 in MnSO4 aqueous solutions at different concentrations was predicted. The study provides theoretical guidance for removing magnesium ions from a MnSO4 aqueous solution via MgF2 precipitation.
研究领域:
化学工程
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
Laser & Photonics Reviews
·
2025
·
IF 10
Jiayi Yang,Ming Cong,Runnan Ye,Wenya Zhao,Xihan Yu,Feng Wang,Guanjun Xiao,Bo Zou
The lack of red emission component with a high color rendering index (CRI) results in a harsh white light-emitting diode. Here, a high-pressure strategy is introduced to achieve a marked piezochromism that shifts from green to red in zero-dimensional (0D) manganese halide (C 6 H 14 N 2 )MnCl 4 . Note that after the pressure is released, the red emission with intense intensity can be stabilized at ambient conditions. The CRI and color purity of the red emission for the quenched (C 6 H 14 N 2 )MnCl 4 are significantly improved to 72 and 85.9% from the initial 14 and 66.5%, respectively. The irreversible pressure-induced amorphization highly contributes to the quenched high-efficiency red emission through the strengthening of the crystal field and Mn–Mn coupling, associated with the shortening of the Mn─Cl bond length and Mn–Mn distance. This work unravels the underlying mechanism of piezochromism from green to red, and retention of intense red emission from the Mn-based metal halides, greatly facilitating the development of new-generation amorphous-state luminescent materials.
研究领域:
材料科学
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光电子学
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固态物理
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 11
·3864-3871
·
IF 4.099
Aolei Gao,Zhenhua Sun,Shaopeng Li,Xinjuan Hou,Huiquan Li,Qisheng Wu,Xinguo Xi
Li1.6Mn1.6O4 is a representative ion sieve material that is used to recover lithium from salt brines and bitterns owing to its high lithium ion adsorption capacity reaching 11.9–44 mg g−1. However, manganese dissolution during acid treatment hinders the industrial application of the material. For investigating the mechanism of manganese dissolution, the precursor Li1.6Mn1.6O4 and ion sieve H1.6Mn1.6O4 were prepared and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), chemical content analyses, diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS). The results of XRD, SEM, and FT-IR showed that the bulk phase of Li1.6Mn1.6O4 retained the spinel structure, whereas the lattice diminished during acid treatment. The results of chemical content analyses showed that the bulk phase of Li1.6Mn1.6O4 contained a few trivalent manganese atoms and that the mean valence of manganese in the material increased during acid treatment. DRIFTS and XPS exhibited that the surface of Li1.6Mn1.6O4 was mostly full of tetravalent manganese and retained the spinel structure during acid treatment. In the proposed mechanism of manganese dissolution, an electron of trivalent manganese in the bulk phase transfers to the surface and is captured by tetravalent manganese within the acidic environment. Then, tetravalent manganese is converted to bivalent manganese after acquiring sufficient electrons, and dissolution occurs simultaneously.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
PROTEINS-STRUCTURE FUNCTION AND BIOINFORMATICS
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2024
·
IF 3.2
Wenwei Tang,Zuxun Huang,Yunying Liu,Xinping Zeng
The microbial manganese removal process is believed to consist of the catalytic oxidation of Mn(II) by manganese oxidase. In this study, the multicopper oxidase CopA was purified and exhibited high manganese oxidation activity in vitro, and it was found that Cu(II) can significantly enhance its manganese oxidation activity. Gene site-directed mutagenesis was used to mutate four conserved copper binding sites of CopA to obtain four mutant strains. The manganese removal efficiencies of the four strains were determined, and it was found that H120 is the catalytically active site of CopA. The loss of Cu(II) and the mutation of the conserved copper binding site H120 resulted in the loss of ethoxyformyl and quinone modifications, a reduction in the number of modifications, and a change in the position of modifications, eventually causing a decrease in protein activity from 85.87% to 70.1%. These results reveal that Cu(II) and H120 play an indispensable role in manganese oxidation by the multicopper oxidase CopA. X-ray photoelectron spectroscopy (XPS) analysis indicates that biogenic manganese oxides produced by strains and by CopA were both composed of MnO 2 and Mn 3 O 4 and that the average valence of Mn was 3.2.
研究领域:
微生物学
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生物化学
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Yiqiao Zhang,Bo Sun,Dandan Rao,Jian Zhang,Shuang Liang
Permanganate (MnO 4 − ), an oxidant that has been applied in water treatment , has highly varied reactivity toward pollutants. In this study, we found manganate (MnO 4 2− ) could destruct diverse functional groups, with oxidation rates being higher than that of permanganate under acidic and neutral conditions. Mechanistic study revealed manganate rapidly disproportionated to permanganate and colloidal MnO 2 in solution. Under acidic conditions, the in-situ formed colloidal MnO 2 possess higher reactivity than permanganate and primarily contributed to the degradation of pollutants. The reactivity of in-situ formed colloidal MnO 2 is highly sensitive to pH and decreased dramatically with increasing pH. Consequently, the contribution of MnO 2 to pollutant removal decreased with elevating pH, which also leads to the decreased degradation efficiency of micropollutants at high pH. Manganate is an intermediate produced during the manufacturing process of permanganate. This study indicates that manganate might be an alternative of permanganate for water purification under acidic and neutral conditions.
研究领域:
环境科学
·
水处理化学
·
污染物降解
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产品关联
DOI
PubMed
高影响因子
Environmental Earth Sciences
·
2022
·Vol. 81
·期 16
·1-12
·
IF 3.119
Feng Wenchao,Wu Jun,Lu Jian
The high concentration of manganese (Mn 2+ ) in geothermal water will seriously reduce its utilization rate. Manganese sand has been used to rapidly remove Mn 2+ from water. This study investigated the long-term removal of Mn 2+ from simulated geothermal water by manganese sand filtration column system. The average Mn 2+ removal rate from simulated water with the inlet water temperature of 25, 50, 70 °C were 87.4%, 96.2% and 99.0% during the operation of 90 days. The effluent pH did not change much compared with influent pH value (7.6–8.0). The Mn 2+ removal rates during the operation of 90 days with influent concentration of 1, 10, 20 and 50 mg/L were respectively 98.2%, 99.8%, 91.4% and 63.4%. The average removal rates of Mn 2+ were respectively 99.8% and 94.0% with the influent flow of 5.2 mL/min and 10.4 mL/min. The temperature change in the manganese sand filtration column was further explored in this paper. The experiment of filtration column heated/non-heated showed that the manganese sand filtration column heated had a better effect of removal which could run for 152 days. The dispersion coefficient ( D ) analysis derived from inverse modeling showed that a small temperature change in the filtration column system was conducive to the homogenization of manganese sand medium in the column. The Mn 2+ removal process of manganese sand filtration column heated was proposed. Surface characteristics analysis of manganese sand in the column after reaction showed that Mn 2+ removal mainly occurred in the upper part of the filter column. The surface material of manganese sand in the filtration column heated after operation was manganese oxide material mainly composed of Mn 2 O 3 and MnO 2 . These findings suggested the potential of manganese sand in the engineering application of removing Mn 2+ in geothermal water.
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Jirong Lan,Yan Sun,Hong Tian,Wei Zhan,Yaguang Du,Hengpeng Ye,Dongyun Du,Tian C. Zhang,Haobo Hou
Slag backfilling with electrolytic manganese residue (EMR) is an economical and environmentally-friendly method. However, high ammonium-nitrogen and manganese ions in EMRs limit this practice. In this study, a method of highly efficient simultaneous stabilization/solidification of ultrafine EMR by making EMR-based cementitious material (named EMR-P) was proposed and tested via single-factor and response surface optimization experiments. Results show that the stabilization efficiency of NH 4 + and Mn 2+ were above 95%, and the unconfined compressive strength of the EMR-P was 18.85 MPa (megapascal = N/mm 2 ). The mechanistic study concluded that the soluble manganese sulfate and ammonium sulfate in EMR were converted into the insoluble precipitates of manganite (MnOOH), gypsum (CaSO 4 ), MnNH 4 PO 4 ·H 2 O, and struvite (MgNH 4 PO 4 ∙6 H 2 O), leading to the stabilization of NH 4 + and Mn 2+ in the EMR-P. Leaching tests of EMR-P indicated that NH 4 + , Mn 2+ , and others heavy metals in the leachate were within the permitted level of the GB/T8978-1996. The novelty of this study includes the addition of phosphate and magnesium ions to precipitate ammonium-nitrogen and the combination between calcium ions (from CaHPO 4 ∙2 H 2 O) and sulfate (from the EMR) to form calcium sulfate to improve the stability and unconfined compressive strength of cementitious materials (EMR-P).
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）