scholarly journals Highly Efficient Adsorption of Aqueous Pb(II) with Mesoporous Metal-Organic Framework-5: An Equilibrium and Kinetic Study

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
José María Rivera ◽  
Susana Rincón ◽  
Cherif Ben Youssef ◽  
Alejandro Zepeda
Keyword(s):  
Kinetic Study ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Isotherm Models ◽  
Ionic Exchange ◽  
Order Kinetic ◽  
X Ray ◽  
Metal Organic ◽  
Mesoporous Metal ◽  
Organic Framework

Mesoporous metal-organic framework-5 (MOF-5), with the composition Zn4O(BDC)3, showed a high capacity for the adsorptive removal of Pb(II) from 100% aqueous media. After the adsorption process, changes in both morphology and composition were detected using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) system, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. The experimental evidence showed that Zn(II) liberation from MOF-5 structure was provoked by the water effect demonstrating that Pb(II) removal is not due to ionic exchange with Zn. A kinetic study showed that Pb(II) removal was carried out in 30 min with a behavior of pseudo-second-order kinetic model. The experimental data on Pb(II) adsorption were adequately fit by both the Langmuir and BET isotherm models with maximum adsorption capacities of 658.5 and 412.7 mg/g, respectively, at pH 5 and 45°C. The results of this work demonstrate that the use of MOF-5 has great potential for applications in environmental protection, especially regarding the removal of the lead present in industrial wastewaters and tap waters.

scholarly journals Metal-Organic Framework MIL-101: Synthesis and Photocatalytic Degradation of Remazol Black B Dye

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Pham Dinh Du ◽  
Huynh Thi Minh Thanh ◽  
Thuy Chau To ◽  
Ho Sy Thang ◽  
Mai Xuan Tinh ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Remazol Black B ◽  
Metal Organic ◽  
Degradation Reaction ◽  
Remazol Black ◽  
Organic Framework

In the present paper, the synthesis of metal-organic framework MIL-101 and its application in the photocatalytic degradation of Remazol Black B (RBB) dye have been demonstrated. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms at 77 K. It was found that MIL-101 synthesized under optimal conditions exhibited high crystallinity and specific surface area (3360 m2·g-1). The obtained MIL-101 possessed high stability in water for 14 days and several solvents (benzene, ethanol, and water at boiling temperature). Its catalytic activities were evaluated by measuring the degradation of RBB in an aqueous solution under UV radiation. The findings show that MIL-101 was a heterogeneous photocatalyst in the degradation reaction of RBB. The mechanism of photocatalysis was considered to be achieved by the electron transfer from photoexcited organic ligands to metallic clusters in MIL-101. The kinetics of photocatalytic degradation reaction were analyzed by using the initial rate method and Langmuir-Hinshelwood model. The MIL-101 photocatalyst exhibited excellent catalytic recyclability and stability and can be a potential catalyst for the treatment of organic pollutants in aqueous solutions.

scholarly journals A STUDY ON HYDROTHERMAL SYNTHESIS OF METAL–ORGANIC FRAMEWORK MIL-101

2017 ◽  
Vol 126 (1C) ◽  
pp. 21
Author(s):  
Võ Thị Thanh Châu ◽  
Hoàng Văn Đức
Keyword(s):  
Hydrothermal Synthesis ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Hydrothermal Process ◽  
Nitrogen Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
Metal Organic ◽  
Adsorption Desorption ◽  
Organic Framework

<p>In the present paper, a synthesis of MIL-101 by hydrothermal process was demonstrated. The obtained samples were characterized by powder X-ray diffraction (PXRD), transmission electron microscope (TEM), nitrogen adsorption/desorption isotherms at 77K, X-ray photoelectron spectroscopy (XPS). The results showed that MIL-101 synthesized by optimal conditions exhibited high crystallinity and surface area. The obtained MIL-101 possesses high stability in water and several organic solvents.</p><p><strong>Keywords:</strong> MIL-101, hydrothermal synthesis, metal organic framework-101. </p>

scholarly journals Detection of Adsorbates on Emissive MOF Surfaces with X-Ray Photoelectron Spectroscopy

2018 ◽  
Author(s):  
Shawn Burdette ◽  
Jingjing Yan ◽  
Ron Grimm ◽  
Peter Mueller ◽  
Alexander Carl ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Analytical Approach ◽  
Metal Organic Framework ◽  
Model System ◽  
Guest Molecules ◽  
X Ray ◽  
Phenol Derivatives ◽  
Metal Organic ◽  
Azobenzene Chromophore ◽  
Organic Framework

A metal organic framework containing an azobenzene chromophore exhibits luminescence that is quenched by nitro-phenol derivatives. The model system was used to develop an new analytical approach to differentiating between encapsulated guest molecules and those adsorbed on the outside of the MOF

scholarly journals Ethanol Sensing Properties and First Principles Study of Au Supported on Mesoporous ZnO Derived from Metal Organic Framework ZIF-8

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4352
Author(s):  
Yanli Kang ◽  
Lu Zhang ◽  
Wenhao Wang ◽  
Feng Yu
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Adsorption Energy ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Metal Organic Framework ◽  
X Ray ◽  
Metal Organic ◽  
Mesoporous Zno ◽  
Organic Framework

It is of great significance to develop ethanol sensors with high sensitivity and low detection temperature. Hence, we prepared Au-supported material on mesoporous ZnO composites derived from a metal-organic framework ZIF-8 for the detection of ethanol gas. The obtained Au/ZnO materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (SEM), field emission transmission electron microscopy (TEM) and nitrogen adsorption and desorption isotherms. The results showed that the Au/ZnO-1.0 sample maintains a three-dimensional (3D) dodecahedron structure with a larger specific surface area (22.79 m2 g−1) and has more oxygen vacancies. Because of the unique ZIF structure, abundant surface defects and the formation of Au-ZnO Schottky junctions, an Au/ZnO-1.0 sensor has a response factor of 37.74 for 100 ppm ethanol at 250 °C, which is about 6 times that of pure ZnO material. In addition, the Au/ZnO-1.0 sensor has good selectivity for ethanol. According to density functional theory (DFT) calculations, the adsorption energy of Au/ZnO for ethanol (−1.813 eV) is significantly greater than that of pure ZnO (−0.217 eV). Furthermore, the adsorption energy for ethanol is greater than that of other gases.

Detection of adsorbates on emissive MOF surfaces with X-ray photoelectron spectroscopy

2019 ◽  
Vol 48 (14) ◽  
pp. 4520-4529 ◽  
Author(s):  
Jingjing Yan ◽  
Alexander D. Carl ◽  
Alex R. Maag ◽  
John C. MacDonald ◽  
Peter Müller ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Surface Adsorption ◽  
Spectroscopic Methods ◽  
Guest Molecules ◽  
X Ray ◽  
Metal Organic ◽  
Azobenzene Chromophore ◽  
Emission Changes ◽  
Organic Framework

The luminescence of azobenzene chromophore struts in a metal organic framework is quenched by nitroaromatic guests. X-ray photoelectron spectroscopic methods verify the emission changes are due to the surface adsorption of the guest molecules rather than encapsulation.

scholarly journals Reversible switching between positive and negative thermal expansion in a metal–organic framework DUT-49

2020 ◽  
Vol 8 (39) ◽  
pp. 20420-20428
Author(s):  
Bikash Garai ◽  
Volodymyr Bon ◽  
Anastasia Efimova ◽  
Martin Gerlach ◽  
Irena Senkovska ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Single Crystal ◽  
Metal Organic Framework ◽  
Negative Thermal Expansion ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Metal Organic ◽  
Mesoporous Metal ◽  
Organic Framework

Reversible switching between positive and negative thermal expansion of a mesoporous metal-organic framework DUT-49 has been demonstrated and studied by synchrotron single-crystal X-ray diffraction with different guest molecules in the pores.

scholarly journals Selective, High-Temperature O2 Adsorption in Chemically Reduced, Redox-Active Iron-Pyrazolate Metal–Organic Frameworks

2019 ◽  
Author(s):  
Adam Jaffe ◽  
Michael Ziebel ◽  
David M. Halat ◽  
Naomi Biggins ◽  
Ryan Murphy ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Chemical Reduction ◽  
Metal Organic Framework ◽  
Outer Sphere ◽  
Electron Transfer Mechanism ◽  
X Ray ◽  
Metal Organic ◽  
Outer Sphere Electron Transfer ◽  
Organic Framework

Developing O<sub>2</sub>-selective adsorbents that can produce high-purity oxygen from air remains a significant challenge. Here, we show that the chemically reduced metal–organic framework A<i><sub>x</sub></i>Fe<sub>2</sub>(BDP)<sub>3</sub> (A = Na<sup>+</sup>, K<sup>+</sup>; BDP<sup>2</sup><sup>−</sup> = 1,4-benzenedipyrazolate; 0 < <i>x</i> ≤ 2), which features coordinatively-saturated iron centers, is capable of strong and selective adsorption of O<sub>2</sub> over N<sub>2</sub> at ambient (25 °C) or even elevated (200 °C) temperature. Through a combination of gas adsorption measurements, single-crystal X-ray diffraction, and numerous spectroscopic probes, including <sup>23</sup>Na solid-state NMR and X-ray photoelectron spectroscopy, we demonstrate that selective O<sub>2</sub> uptake likely occurs as a result of outer-sphere electron transfer from the framework to form superoxide species, which are subsequently stabilized by intercalated alkali metal cations that reside in the one-dimensional triangular pores of the framework. The chemical reduction of a robust metal–organic framework to render it capable of binding O<sub>2</sub> through an outer-sphere electron transfer mechanism thus represents a promising and underexplored strategy for the design of next-generation O<sub>2</sub> adsorbents.

scholarly journals Synthesis of MIL-53(Fe) Metal-Organic Framework Material and Its Application as a Catalyst for Fenton-Type Oxidation of Organic Pollutants

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pham Dinh Du ◽  
Pham Ngoc Hoai
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Reaction System ◽  
Molar Ratio ◽  
X Ray ◽  
Metal Organic ◽  
Adsorption Desorption ◽  
Organic Framework

The iron (III) benzene dicarboxylate metal-organic framework material (MIL-53(Fe)) was synthesized with either the solvent-thermal or hydrothermal method under different conditions. The influence of the type of solvents, molar ratio of precursors and solvent, temperature, and reaction time on the structure of MIL-53(Fe) was investigated. The material was characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption/desorption isotherm. The MIL-53(Fe) structure formed in N′, N-dimethylformamide (DMF) and methanol (MeOH) but not in water. In DMF, the molar ratio of precursors and solvent, temperature, and reaction time had a significant effect on the crystal structure of MIL-53(Fe). Under optimal conditions, MIL-53(Fe) has high crystallinity and a large specific surface area ( S BET  = 88.2 m2/g). The obtained MIL-53(Fe) could serve as a potential heterogeneous catalyst to oxidize phenol (PhN), rhodamine B (RhB), and methylene blue (MtB) in the Fenton-like reaction system at the different solution pHs.

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