scholarly journals Carbon Molecular Sieve Membranes from Polyetherimide: Effect of Pyrolysis Temperature on O2/N2 Selectivity

2017 ◽  
Vol 14 (1) ◽  
Author(s):  
M. A. Ahmad ◽  
N. K. A. Rashid ◽  
B. H. Hameed
Keyword(s):  
Molecular Sieve ◽  
Pyrolysis Temperature ◽  
Gas Permeability ◽  
High Surface ◽  
High Surface Area ◽  
Carbon Layer ◽  
Separation Performance ◽  
Carbon Molecular Sieve ◽  
Carbon Structures ◽  
Thin Carbon

Carbon molecular sieve (CMS) membranes with excellent separation performance and stability appear to be promising candidate for gas separation. In this work, CMS membranes were formed by a thin carbon layer obtained by pyrolysis of a coated polyetherimide solution onto porous disk support. The pyrolysis temperatures were varied under inert condition. Results showed that the pyrolysis temperature played an important role in determining the gas permeability of CMS membranes. The CMS membrane prepared at pyrolysis temperature of 700°C shows high surface area and narrow PSD with well developed microporous carbon structures. The development of large pore occurs at higher pyrolysis temperature. The O2/N2 permselectivities of 2.86, 2.61 and 2.22, respectively were attained by CMS membranes prepared at pyrolyzed temperature of 700, 800 and 900°C.

scholarly journals Tailoring the Stabilization and Pyrolysis Processes of Carbon Molecular Sieve Membrane Derived from Polyacrylonitrile for Ethylene/Ethane Separation

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
DaeHun Kim ◽  
YongSung Kwon ◽  
Jung-Hyun Lee ◽  
Seong-Joong Kim ◽  
You-In Park
Keyword(s):  
Molecular Sieve ◽  
Pyrolysis Temperature ◽  
Separation Performance ◽  
Carbon Molecular Sieve ◽  
Alumina Support ◽  
Soaking Time ◽  
Polymer Precursors ◽  
Pre Treatment ◽  
Excellent Thermal Property ◽  
Pyrolysis Processes

For ethylene/ethane separation, a CMS (carbon molecular sieve) membrane was developed with a PAN (polyacrylonitrile) polymer precursor on an alumina support. To provide an excellent thermal property to PAN precursor prior to the pyrolysis, the stabilization as a pre-treatment process was carried out. Tuning the stabilization condition was very important to successfully preparing the CMS membrane derived from the PAN precursor. The stabilization and pyrolysis processes for the PAN precursor were finely tuned, and optimized in terms of stabilization temperature and time, as well as pyrolysis temperature, heating rate, and soaking time. The PAN stabilized at >250 °C showed improved thermal stability and carbon yield. The CMS membrane derived from stabilized PAN showed reasonable separation performance for ethylene permeance (0.71 GPU) and ethylene/ethane selectivity (7.62), respectively. Increasing the pyrolysis temperature and soaking time gave rise to an increase in the gas permeance, and a reduction in the membrane selectivity. This trend was opposite to that for the CMS membranes derived from other polymer precursors. The optimized separation performance (ethylene permeance of 2.97 GPU and ethylene/ethane selectivity of 7.25) could be achieved at the pyrolysis temperature of 650 °C with a soaking time of 1 h. The separation performance of the CMS membrane derived from the PAN precursor was comparable to that of other polymer precursors, and surpassed them regarding the upper bound trade off.

scholarly journals Isomer‐Tailored Carbon Molecular Sieve Membranes with High Gas Separation Performance

ChemSusChem ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5318-5328
Author(s):  
Wulin Qiu ◽  
Fuyue Stephanie Li ◽  
Shilu Fu ◽  
William J. Koros
Keyword(s):  
Gas Separation ◽  
Molecular Sieve ◽  
Separation Performance ◽  
Carbon Molecular Sieve ◽  
Gas Separation Performance

Gas permeability of carbon aerogels

1993 ◽  
Vol 8 (12) ◽  
pp. 3100-3105 ◽  
Author(s):  
F-M. Kong ◽  
J.D. LeMay ◽  
S.S. Hulsey ◽  
C.T. Alviso ◽  
R.W. Pekala
Keyword(s):  
Pore Size ◽  
Gas Flow ◽  
Gas Permeability ◽  
High Surface ◽  
High Surface Area ◽  
Supercritical Drying ◽  
Flow Equation ◽  
Carbon Aerogels ◽  
Thin Specimen ◽  
Potential Applications

Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 °C. As a result of their interconnected porosity, ultrafine cell/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, the permeability of carbon aerogels was calculated from equations based upon Darcy's law. Our measurements show that carbon aerogels have permeabilities on the order of 10−12 to 10−10 cm2 over the density range from 0.05–0.44 g/cm3. Like many other aerogel properties, the permeability of carbon aerogels follows a power law relationship with density, reflecting differences in the average mesopore size. Comparing the results from this study with the permeability of silica aerogels reported by other workers, we found that the permeability of aerogels is governed by a simple universal flow equation. This paper discusses the relationship among permeability, pore size, and density in carbon aerogels.

Carbonaceous materials as substitutes for conventional dye-sensitized solar cell counter electrodes

2015 ◽  
Vol 3 (42) ◽  
pp. 20849-20862 ◽  
Author(s):  
H. Ghorbani Shiraz ◽  
F. Razi Astaraie
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Dye Sensitized Solar Cell ◽  
Counter Electrodes ◽  
Dye Sensitized ◽  
Carbon Structures ◽  
Cell Counter

Carbon structures present high surface area as well as low impedance, which lead to efficient solar cells.

Surface modification effect of carbon molecular sieve (CMS) on the morphology and separation performance of mixed matrix membranes

2019 ◽  
Vol 80 ◽  
pp. 106152 ◽  
Author(s):  
Amelia S. Wiryoatmojo ◽  
Hafiz Abdul Mannan ◽  
Rizwan Nasir ◽  
Hilmi Mukhtar ◽  
Dzeti Farhah Mohshim ◽  
...  
Keyword(s):  
Surface Modification ◽  
Molecular Sieve ◽  
Mixed Matrix Membranes ◽  
Separation Performance ◽  
Mixed Matrix ◽  
Carbon Molecular Sieve ◽  
Modification Effect ◽  
Matrix Membranes

A Mini Review on Carbon Molecular Sieve Membrane for Oxygen Separation

2020 ◽  
Vol 4 (1) ◽  
pp. 23-35
Author(s):  
Fatin Nurwahdah Ahmad ◽  
Norazlianie Sazali ◽  
Mohd Hafiz Dzafran Othman
Keyword(s):  
Molecular Sieve ◽  
High Performance ◽  
Separation Performance ◽  
Carbon Membrane ◽  
Carbon Molecular Sieve ◽  
Carbon Membranes ◽  
Advantages And Disadvantages ◽  
Polymer Precursors ◽  
And Performance

Membrane-based technology has proved its practicality in gas separation through its performance. Various type of membranes has been explored, showing that each type of them have their own advantages and disadvantages. Polymeric membranes have been widely used to separate O2/N2, however, its drawbacks lead to the development of carbon molecular sieve membrane. Carbon molecular sieve membranes have demonstrated excellent separation performance for almost similar kinetic diameter molecules such as O2/N2. Many polymer precursors can be used to produce carbon molecular sieve membrane through carbonization process or also known as heat treatment. This paper discusses the variety of precursors and carbonization parameters to produce high quality and performance of carbon molecular sieve membranes.  This paper covers the evaluation in advancement and status of high-performance carbon membrane implemented for separating gas, comprising the variety of precursor materials and the fabrication process that involve many different parameters, also analysis of carbon membranes properties in separating various type of gas having high demand in the industries. The issues regarding the current challenges in developing carbon membrane and approaches with the purpose of solving and improving the performance and applications of carbon membrane are included in this paper. Also, the advantages of the carbon membrane compared to other types of membranes are highlighted. Observation and understanding the variables affecting the quality of membrane encourage the optimization of conditions and techniques in producing high-performance membrane.

Effects of Pyrolysis Temperature on the Properties of Phenol-Formaldehyde Resin Based Carbon Molecular Sieve Membrane

2016 ◽  
Vol 848 ◽  
pp. 738-742
Author(s):  
Jia Jia Li ◽  
Wei Wei ◽  
Qiang Lin ◽  
Jing Yi Zhang
Keyword(s):  
Pore Size ◽  
Molecular Sieve ◽  
Pyrolysis Temperature ◽  
Phenol Formaldehyde ◽  
Phenol Formaldehyde Resin ◽  
Membrane Properties ◽  
Formaldehyde Resin ◽  
Carbon Membrane ◽  
Carbon Molecular Sieve ◽  
Effective Pore Size

Carbon molecular sieve membranes were prepared by pyrolysis of novolac type phenol-formaldehyde resin. The influences of pyrolysis temperature on membrane properties were investigated. By raising the pyrolysis temperature from 600 oC to 700 oC, the number of pores and effective pore size increased, thereby making the carbon membrane more productive but less selective. When the pyrolysis temperature from 700 oC to 900 oC, the effective pore size was reduced by sinter effect, thereby the gas permeation rate decreased and selectivity increased. The carbon membranes were characterized by elemental analysis, X-ray diffraction (XRD), and CO2 adsorption. H2, N2, CH4, and O2 were used for pure gas tests to evaluate membrane performance.

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