scholarly journals Preparation and Characterization of Metal Membranes for Gas Separation

2021 ◽  
Vol 12 (4) ◽  
pp. 4649-4661
Keyword(s):  
Sandwich Structure ◽  
Structure Characterization ◽  
Effect Of Temperature ◽  
Structure And Properties ◽  
Membrane Systems ◽  
Gas Phases ◽  
Ideal Selectivity ◽  
Exogenous Factors ◽  
The Ideal

The purpose of this article is the characterization of permeability and the ideal selectivity of new metallic brass membranes with a “sandwich” structure. Characterization is an important factor related to the morphology, structure, and properties of the membrane. The membranes were examined for simple gas phases, including various exogenous factors on their performance (temperature, pressure, durability). To evaluate their performance, permeate measurements were made at temperatures from -18 to 300°C and at various pressures from 1 to 10 bar. Results have shown that permeability is influenced by the molecular weight and exhibits ideal selectivity greater or equal by Knudsen’s ideal separation factor in a sequence of Η2>He>CH4>N2>O2>Ar≥CO2. The permeability is also a function of the thickness of the membrane, as it shows there’s a decrease in permeability and an increase in selectivity when the thickness is increased. The effect of temperature on these metal membranes is considered an important factor in the operation of membranes and membrane systems. The main feature is the reduction of permeability with the increase of temperature.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. XLII. [Cu4X4L4] 'Cubane' Clusters, L = Hindered N-Base Ligand: Synthesis and Structure of the L = 2-(Diphenylmethyl)pyridine Complexes (X = Cl, Br, I)

1989 ◽  
Vol 42 (1) ◽  
pp. 107 ◽  
Author(s):  
LM Engelhardt ◽  
PC Healy ◽  
JD Kildea ◽  
AH White
Keyword(s):  
Bond Distance ◽  
Lewis Base ◽  
Structure Characterization ◽  
Hydrogen Atoms ◽  
X Ray ◽  
The Core ◽  
C 30 ◽  
The Ideal ◽  
Cubane Clusters

The synthesis and single-crystal X-ray structure characterization of tetrameric cubane clusters of copper(1) halides with the hindered N-base ligand 2-(diphenylmethy1)pyridine are reported. The chloride, bromide and iodide structures are isomorphous , crystallizing in the tetragonal space group 141/a, a ≈ 23, c ≈ 12 � , Z = 4 tetramers, the tetramer having crystallographically imposed 4 symmetry, well removed from the ideal 43m. In terms of each X3CuN fragment of the core, this distortion results in one of the N-Cu-X angles being enlarged by c. 30� with respect to the other two and one Cu-X bond distance shortened. Cu-N is also shorter than is usual in a four-coordinate environment and the cluster can be envisaged as being constructed from four quasi-linear monomers. The distortions may be attributed to interaction between the 6- and 2-α-substituent-hydrogen atoms and the halide atoms of the core. The effect diminishes with increasing halide size and increasing volume of the Cu4X4 core.

Preparation and Characterization of Newly Developed Polysulfone/Polyethersulfone Blend Membrane for CO2 Separation

2014 ◽  
Vol 699 ◽  
pp. 325-330 ◽  
Author(s):  
Hafiz Abdul Mannan ◽  
Hilmi Mukhtar ◽  
Thanabalan Murugesan
Keyword(s):  
Polymeric Membranes ◽  
Polymer Blending ◽  
Blend Ratio ◽  
Flat Sheet ◽  
Ideal Selectivity ◽  
Blend Membranes ◽  
Physical Mixing ◽  
Individual Polymer ◽  
The Ideal

Polymeric membranes suffer from so called upper bound tradeoff between permeability and selectivity as described by Robeson. Polymer blending is a valuable technique to tune the properties of polymeric membranes by physical mixing of different polymers in a single mixture. In this study, preparation and characterization of newly developed polysulfone/polyethersulfone (PSF/PES) blend flat sheet dense membranes is described for CO2/CH4 separation. Blend membranes with different blending ratios were prepared and the developed membranes were characterized by FESEM, FTIR and TGA to see the effect of blend ratio on morphology, bonding and thermal stability respectively. Permeability of CO2 and CH4 gases in pressure range of 2-10 bar is recorded to find out the ideal selectivity of prepared membranes. The results are discussed and compared with individual polymer membranes.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

scholarly journals Common Phase and Structure Misidentifications in High-Resolution TEM Characterization of Perovskite Materials

2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Yu-Hao Deng
Keyword(s):  
High Resolution ◽  
Research Field ◽  
Structure Characterization ◽  
Phase Identification ◽  
Lead Iodide ◽  
Perovskite Materials ◽  
High Resolution Tem ◽  
Methylammonium Lead Iodide ◽  
Dose Imaging

High-resolution TEM (HRTEM) is a powerful tool for structure characterization. However, methylammonium lead iodide (MAPbI3) perovskite is highly sensitive to electron beams and easily decomposes into lead iodide (PbI2). Misidentifications, such as PbI2 being incorrectly labeled as perovskite, are widely present in HRTEM characterization and would negatively affect the development of perovskite research field. Here misidentifications in MAPbI3 perovskite are summarized, classified, and corrected based on low-dose imaging and electron diffraction (ED) simulations. Corresponding crystallographic parameters of intrinsic tetragonal MAPbI3 and the confusable hexagonal PbI2 are presented unambiguously. Finally, the method of proper phase identification and some strategies to control the radiation damage in HRTEM are provided. This warning paves the way to avoid future misinterpretations in HRTEM characterization of perovskite and other electron beam-sensitive materials.

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