ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2015
·Vol. 408
·期 4
·1231-1236
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IF 3.436
He Yi,Wang Zeru,Long Dengying
The increasing application of nanomaterials will inevitably lead to their release into the environment, which may pose a threat to the environment and human health. As such, there is an urgent need to detect various nanomaterials. In the present work, we present a novel, rapid, and simple visual detection of MnO 2 nanosheets in buffer solution and environmental water sample. In this assay, a redox reaction between MnO 2 nanosheets and 3,3′,5,5′-tetramethylbenzidine (TMB) occurred, leading to the oxidation of TMB to TMB diimine. This redox reaction generated different colors dependent on the concentration of MnO 2 nanosheets, including colorless, blue, green, and yellow, which allowed semiquantitative detection of MnO 2 nanosheets with the naked eye. The detection range of the visual assay was 2–15 μg/mL, and the minimum concentration of MnO 2 nanosheets can be visually detected at concentrations down to 2.0 μg/mL. Moreover, the developed visual assay showed a high selectivity to MnO 2 nanosheets over Mn 2+ ions, tetramethylammonium hydroxide, hydrogen peroxide, graphene oxide, and graphitic carbon nitride nanosheets.
Visual detection of MnO 2 nanosheets
研究领域:
环境科学
·
纳米技术
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2025
·
IF 9
Yanchuan Zhang,Yali Zhao,Yu Liu
Loose nanofiltration (NF) membranes are promising in textile wastewater treatment due to their selective separation capabilities for dyes and salts. However, their widespread applications are hindered by complex manufacturing processes and membrane fouling. This work focuses on fabricating antifouling loose NF membranes using a facile method. Thereinto, amine-functionalized loose NF matrixes were first prepared using polyelectrolyte-complex induced phase inversion, where polyethyleneimine (PEI) in a coagulation bath as an inducer triggered an instantaneous phase inversion via electrostatic interactions with sulfonated polysulfone (SPSF) in dope solution. The acquired NF matrix has a dense skin layer with a mean pore size of 0.72 nm, endowing it with excellent dye retention. Consequently, the Fenton catalyst, MnO 2 , was in situ grown on the membrane via the interaction between amine and Mn 2+ followed by a one-step mineralization reaction. The MnO 2 -loaded loose NF membrane could achieve 99.7 % CR rejection while allowing only 1.67 % rejection of Na 2 SO 4 in a mixed solution of 60 mg/L Congo Red (CR) and 20 g/L Na 2 SO 4 at the permeability of 51.6 L m −2 h −1 ·bar −1 . After cleaning with H 2 O 2 , the flux recovery rate of the membrane remains above 97 %, attributed to the catalytic effect of MnO 2 on the membrane surface. Additionally, the membrane displayed similar performance in dealing with real wastewater, underscoring its potential for practical applications in textile wastewater treatment.
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
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Zilong Zhang,Shuai Wang,Yangyang Lv,Xiqiao Chen,Zhuang Wu,Yanhong Zou
In this work, MnO 2 -deposited graphene foams (MnO 2 /GFs) were synthesized using a simple hydrothermal method . By controlling the content of MnO 2 deposited on the surface of graphene skeleton, a series of MnO 2 /GFs composites are easily synthesized. Benefiting from the well-designed interconnected 3D porous network structure and strong interfacial polarization between MnO 2 nanoparticles and graphene skeleton, the MnO 2 /GFs composite displays excellent microwave absorbing properties. The optimized MnO 2 /GFs nanocomposite achieves the strongest electromagnetic absorption with a reflection loss (RL) of −53 dB and the qualified absorption bandwidth is up to 7.0 GHz. The results may provide some valuable design guidelines for lightweight, wide-band, and highly efficient electromagnetic wave absorption materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
Catalysts
·
2023
·Vol. 13
·期 3
·490
·
IF 3.9
Wenrui Zhang,Meilu Hao,Yonghui Wang,Pengfei Sun,Dongjuan Zeng,Xinya Wang,Peng Liang
Layered δ-MnO2catalysts were prepared using the one-step redox method in precursor solutions with five different pH values (pH = 7, 9, 11, 13, and 14). The effects of pH on the physical properties and catalytic activity of the catalyst were investigated through XRD, SEM, TEM, BET, XPS, H2-TPR, and HCHO degradation tests at room temperature. The results showed that the layer spacing, manganese vacancy content, Mn4+/Mn3+ratio, and surface-reactive oxygen species content of MnO2increased with the increase in pH value in the alkaline range. When the catalyst was prepared at pH = 13, the above characteristics of the catalyst reached the optimal value which contributed to the high catalytic activity. Combined with the related characterization results, it was proved that changing the pH can affect the degree of oxidation in the catalyst synthesis process, increase the number of active oxygen and the oxygen mobility of the catalyst, and effectively improve the catalytic activity of the manganese dioxide catalyst for HCHO. This work represents a giant step toward the preparation of an effective catalyst for practical applications of HCHO removal at room temperature at a low concentration and high velocity.Keywords:δ-MnO2;pH;formaldehyde;manganese vacancy;surface-reactive oxygen species
研究领域:
催化
·
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 20
·18950-18958
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IF 2.195
Fu Mingtao,Li Caixia,Yang Bin,Liu Danqing,Bian Lang,Hong Yuenan,Zhang Changhai,Chen Chuntian,Lin Jiaqi
The Ba 0.985 Ca 0.005 Ti 0.98 Sn 0.02 O 3 + x mol% MnO 2 (BCTSM x , x = 0, 0.2, 0.3, 0.4, 0.5 and 0.6) ceramics were fabricated by conventional solid-state reaction method. The effects of MnO 2 doping on the phase structure, microstructure, dielectric, ferroelectric and piezoelectric properties of Ba 0.985 Ca 0.005 Ti 0.98 Sn 0.02 O 3 ceramics were investigated systematically. X-ray diffraction patterns revealed that the BCTSM x ceramics are composed of coexisting tetragonal-orthogonal phases. The addition of MnO 2 could significantly improve the sinterability of BCTS ceramics. The BCTSM x ceramics with x = 0.4 demonstrated an optimum electrical properties: ε r = 2802, tan δ = 0.081, T C = 121 °C, ε max = 9977, P r = 11.8 μC/cm 2 , E C = 2.6 kV/cm, bipolar S max = 0.25%, unipolar S max = 0.28%, d
* 33
= 1093 pm/V, d 33 = 325 pC/N, k p = 43.2%, and Q m = 118.
研究领域:
材料科学
·
无机非金属材料
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Yi He,De Bin Jiang,Jie Chen,De Yi Jiang,Yu Xin Zhang
In this research, MnO 2 nanosheets on montmorillonite (MnO 2 nanosheets@MMt) was synthesized by one-pot hydrothermal method and characterized by X-ray diffraction, Fourier transform infrared spectra , nitrogen adsorption and scanning electron microscopy. It was found that honeycomb-like MnO 2 nanosheets vertically grew on the surface of montmorillonite. MnO 2 nanosheets@MMt exhibited high methylene blue (MB) removal rate, which reached 97.7% within 5 min under the condition of pH 2, MnO 2 nanosheets dosage of 0.1 g L −1 and initial dye concentration of 10 mg L −1 . Additionally, the influencing factors such as pH value, amount of MnO 2 nanosheets@MMt, and MB concentration were also investigated in this paper. Results showed the MB degradation process was correlated with pH value, and the MnO 2 nanosheets@MMt achieved MB removal rate of 92.8% within 5 min under pH 11 because of its absorption capacity of MB. The kinetics of the adsorption process complied with the Pseudo-second-order model. The Langmuir model was found to be the most suitable for describing the experimental equilibrium data of MnO 2 nanosheets@MMt. The MnO 2 nanosheets@MMt showed high adsorption capacity of 363.63 mg g −1 for MB dye. The oxidative decomposition of MB was conducted in the presence of MnO 2 nanosheets@MMt in the low pH, finding that the lower the pH was, the faster the degradation rate was. This research demonstrates that MnO 2 nanosheets@MMt has potential applications in wastewater treatment .
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2019
·Vol. 48
·期 7
·4653-4659
·
IF 1.676
Lei Dongling,Ma Shiyu,Lu Youcai,Liu Qingchao,Li Zhongjun
A rechargeable Li-CO 2 battery has been considered to be a promising battery system due to its high-energy density and the utilization of carbon dioxide (CO 2 ). However, the high overvoltage caused by the discharge product Li 2 CO 3 hinders the development of Li-CO 2 batteries. In this work, α-MnO 2 nanowires obtained via a redox reaction have been employed as the cathode catalyst in the Li-CO 2 battery, which can provide sufficient catalytic sites for CO 2 evolution and tune the cathode structure for the uniform distribution of Li 2 CO 3 and C on the cathode. The Li-CO 2 battery with an MnO 2 /carbon nanotube (CNT) cathode exhibits significantly reduced overpotential, and could be operated for 50 cycles with a fixed capacity of 1000 mAh g −1 and 6 cycles of full discharge–charge tests at a current density of 100 mA g −1 .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Jun Zhai,Quanfeng Wang,Qing Li,Bo Shang,Md. Hasibur Rahaman,Jialiang Liang,Jiucui Ji,Wenbo Liu
Carbamazepine (CBZ), a widely used antiepileptic drug, is refractory to biological wastewater treatment . Rapid removal of CBZ is possible using synthetic manganese oxide (δ-MnO 2 ) but the removal mechanisms require further investigation. In this study, CBZ degradation by δ-MnO 2 was carried out at different pH to further explore the degradation mechanisms. Results show that CBZ degradation by δ-MnO 2 was highly pH dependent, and rapid degradation occurred when pH <2.8. Based on the density functional theory calculations, increasing [H + ] not only increased the reactivity of δ-MnO 2 , but also enhanced the secondary reactions of the intermediates. During the degradation process, protonation of CBZ degradation intermediates, instead of CBZ, played an important role. The overall kinetics of CBZ degradation was then described by the retarded first-order model. The initial rate (r init ) in the model between pH 2.0 and 6.2 was determined to be r init = (2.41 ± 0.51) × 10 −3 [CBZ] 1.21 [MnO 2 ] 1.07 [H + ] 1.41 . This is the first report revealing that protonation of intermediates from CBZ degradation can improve the CBZ oxidation by δ-MnO2. The pathways of CBZ degradation by δ-MnO 2 were also proposed. The results of this study provide a new insight into the processing mechanism.
研究领域:
环境科学
·
药物化学
✓ 已验证
DOI
PubMed
高影响因子
Materials Horizons
·
2025
·
IF 10.7
Yiliang Liu,Ying Lin,Zhixin Cai,Yongzhen Ma,Hongwei Zhou,Wei Chai,Qibin Yuan,Haibo Yang
With the rapid development of modern electronic technology, electromagnetic wave (EMW) absorption materials play a crucial role in solving the problem of electromagnetic radiation pollution. By designing unique microstructures or composite magnetic components, the EMW attenuation ability of carbon nanofibers (CNFs) can be enhanced. However, the ultra-high conductivity of CNFs leads to impedance mismatch, necessitating the introduction of components that can rapidly optimize dielectric properties for improved impedance matching. In this study, Co0.7Fe0.3@CNFs@MnO2 (CFCM) was fabricated by coating MnO2 nanosheets on necklace-like CoFe@carbon nanofiber composites. The coated MnO2 nanosheets not only enhance the EMW attenuation ability, but also improve impedance matching. The results indicate that the minimum reflection loss of the sample is −62.7 dB, and the effective absorption bandwidth reaches 6.5 GHz. This work presents a valuable method to prepare outstanding EMW absorption materials with a necklace-like 3D network hierarchical structure.
研究领域:
材料科学
·
电子工程
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2019
·Vol. 8
·期 16
·3542-3549
·
IF 5.047
Mohamed Ibrahim Halawa,Fengxia Wu,Muhammad Nadeem Zafar,Islam M. Mostafa,Abubakar Abdussalam,Shuang Han,Guobao Xu
In this work, a glutathione (GSH) sensing nano-platform using lucigenin as a fluorescent probe in the presence of MnO2 nanosheets was reported for the first time. Unlike the earlier fluorescent detection systems based on MnO2 nanosheets, which depend on Förster resonance energy transfer (FRET) or the dynamic quenching effect (DQE), the mechanism of the quenching process of MnO2 nanosheets on lucigenin fluorescence was attributed mainly to a static quenching effect (SQE) with a minor contribution of the inner filter effect (IFE). A double exponential fluorescence decay of lucigenin was obtained in various MnO2 nanosheet concentrations as a result of their SQE and IFE. Based on this phenomenon and taking advantage of the redox reaction between GSH and MnO2 nanosheets, we have developed a switch-on sensitive fluorescent method for GSH via the recovery of the MnO2 nanosheet-quenched fluorescence of lucigenin. A good linearity range of 1.0–150.0 μM with a low limit of detection (S/N = 3) of 180.0 nM was achieved, revealing the higher sensitivity for GSH determination in comparison with the previously reported MnO2 nanosheet-based turn-on fluorescent methods. The developed fluorescent nano-platform exhibits excellent selectivity with successful application for GSH detection in human serum plasma, indicating its good practicability for GSH sensing in biological and clinical applications.
研究领域:
分析化学
·
生物医学工程
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemNanoMat
·
2022
·Vol. 8
·期 9
·e202200243
·
IF 3.82
Xueyang Wang,Fanshu Yuan,Dan Xue,Jie Liu,Jie Wei,Yiwen Wang,Jiahui Wang,Qinghua Qu,Qianli Zhang
Graphical A binder-free electrode was constructed by decorating MnO 2 nanoflowers onto the hybrid material of ZIF-8/ZnO, as derived from ZIF-8 via pyrolysis. Both the composite electrode and the NF/ZIF-8-ZnO/MnO 2 //activated carbon (AC) asymmetric supercapacitor demonstrate excellent electrochemical performance, showing that NF/ZIF-8-ZnO/MnO 2 is a promising candidate for supercapacitors due to the synergistic contribution of ZIF-8, ZnO and MnO 2 . In this study, ZIF-8 (Zn(MeIn) 2 , MeIn=2-methylimidazole) was synthesized directly on Ni foam with the use of polydopamine (PDA). By following a hydrothermal process, MnO 2 nanoflowers were decorated on the hybrid material of ZIF-8/ZnO, as derived from ZIF-8 via pyrolysis at 500 °C under nitrogen flow. The produced binder-free electrode (NF/ZIF-8-ZnO/MnO 2 ) demonstrated an excellent electrochemical performance for supercapacitors, including a specific capacitance of 2005 F g −1 at 2 A g −1 and a fairly high cycling stability (90.74% retention after 4000 cycles). Furthermore, a NF/ZIF-8-ZnO/MnO 2 //activated carbon (AC) asymmetric supercapacitor showed an energy density of 70.57 Wh kg −1 given a power density of 112.45 kW kg −1 . These results demonstrate that NF/ZIF-8-ZnO/MnO 2 is a promising candidate for supercapacitors due to the synergistic contribution of ZIF-8, ZnO and MnO 2 .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2019
·
IF 6.361
Xingliang Chen,Zirui Jia,Ailing Feng,Bingbing Wang,Xiaohua Tong,Chuanhui Zhang,Guanglei Wu
In this work, a novel Fe 3 O 4 @C@MnO 2 hybrid was successfully synthesized via facile method. The morphology, structure, chemical composition , magnetic behavior and EM wave absorbing performance of the hybrid were systematically investigated. Results indicate that the hybrid possesses uniform hierarchical and mesoporous structure. The magnetic saturation(Ms) value of the hybrid is 19.8 emu g −1 , which is beneficial to improve magnetic loss. According to its reflection loss curve, the hybrid performs superior EM wave absorption capacity, with a minimum reflection loss value and effective absorbing bandwidth of −35 dB and 5 GHz when the specimen thickness is 2.7 mm. The excellent performance of this hybrid can mainly be attributed to its ideal matching of magnetic loss and dielectric loss, large specific surface area, mesoporous structure and interfacial polarizations. Such new material has the potential to be a superior electromagnetic wave absorber, or applied as a functional filler to modify resin matrix.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）