scholarly journals Mixed-Gas Selectivity Based on Pure Gas Permeation Measurements: An Approximate Model

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 833
Author(s):  
Alexander O. Malakhov ◽  
Vladimir V. Volkov
Keyword(s):  
Gas Permeability ◽  
Approximate Model ◽  
Polymeric Membranes ◽  
Mixture Component ◽  
Mixed Gas ◽  
Ideal Selectivity ◽  
Local Permeability ◽  
Input Parameters ◽  
Gas Selectivity ◽  
The Ideal

An approximate model based on friction-coefficient formalism is developed to predict the mixed-gas permeability and selectivity of polymeric membranes. More specifically, the model is a modification of Kedem’s approach to flux coupling. The crucial assumption of the developed model is the division of the inverse local permeability of the mixture component into two terms: the inverse local permeability of the corresponding pure gas and the term proportional to the friction between penetrants. Analytical expressions for permeability and selectivity of polymeric membranes in mixed-gas conditions were obtained within the model. The input parameters for the model are ideal selectivity and solubility coefficients for pure gases. Calculations have shown that, depending on the input parameters and the value of the membrane Peclét number (the measure of coupling), there can be both a reduction and an enhancement of selectivity compared to the ideal selectivity. The deviation between real and ideal selectivity increases at higher Peclét numbers; in the limit of large Peclét numbers, the mixed-gas selectivity tends to the value of the ideal solubility selectivity. The model has been validated using literature data on mixed-gas separation of n-butane/methane and propylene/propane through polymeric membranes.

Effects of 60Co-Irradiation on Gas Permeation Properties of Polyimide Membranes

2014 ◽  
Vol 912-914 ◽  
pp. 123-126
Author(s):  
Yu Hua Qiao ◽  
Huai Min Miao ◽  
Yong Biao Xu ◽  
Wei Jiang ◽  
Yan Hong Zheng ◽  
...  
Keyword(s):  
Gas Separation ◽  
Radiation Effects ◽  
Gas Permeability ◽  
Gas Permeation ◽  
Ideal Selectivity ◽  
Tetracarboxylic Dianhydride ◽  
Permeation Properties ◽  
The Ideal ◽  
Polyimide Membranes

Radiation effects on polyimide (PI) membranes were studied with different irradiation doses by60Co. The PI membrane were synthesized from 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (Bis-AP-AF) with 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA). The single gas permeability of He, H2, CO2, O2, N2and CH4were measured and compared in order to determine the effect of the the irradiation doses on the gas separation properties. The results showed that the ideal selectivity of He/CH4, H2/CH4, CO2/CH4and H2/N2of the irradiation PI membrane can be significantly improved by irradiation of60Co source. The optimum irradiation doses were 50 kGy. The highest ideal selectivity of He/CH4, H2/CH4, CO2/CH4and H2/N2is 3635.86, 2287.57, 282.00 and 205.29, respectively. In other word, the ideal selectivity of He/CH4, H2/CH4, CO2/CH4and H2/N2of the irradiation PI membrane with 50 kGy irradiation doses is 2.27, 2.11, 1.89 and 1.08 times higher than that of the PI membranes without irradiation.

scholarly journals Glassy PEEK-WC vs. Rubbery Pebax®1657 Polymers: Effect on the Gas Transport in CuNi-MOF Based Mixed Matrix Membranes

2020 ◽  
Vol 10 (4) ◽  
pp. 1310 ◽  
Author(s):  
Elisa Esposito ◽  
Rosaria Bruno ◽  
Marcello Monteleone ◽  
Alessio Fuoco ◽  
Jesús Ferrando Soria ◽  
...  
Keyword(s):  
Gas Transport ◽  
Effective Diffusivity ◽  
Polymeric Membranes ◽  
Mixed Matrix Membranes ◽  
Mechanical And Thermal Properties ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Scanning Calorimetry ◽  
The Ideal ◽  
Matrix Membranes

Mixed matrix membranes (MMMs) are seen as promising candidates to overcome the fundamental limit of polymeric membranes, known as the so-called Robeson upper bound, which defines the best compromise between permeability and selectivity of neat polymeric membranes. To overcome this limit, the permeability of the filler particles in the MMM must be carefully matched with that of the polymer matrix. The present work shows that it is not sufficient to match only the permeability of the polymer and the dispersed phase, but that one should consider also the individual contributions of the diffusivity and the solubility of the gas in both components. Here we compare the gas transport performance of two different MMMs, containing the metal–organic framework CuNi-MOF in the rubbery Pebax®1657 and in the glassy poly(ether-ether-ketone) with cardo moiety, PEEK-WC. The chemical and structural properties of MMMs were investigated by means of FT-IR spectroscopy, scanning electron microscopy and EDX analysis. The influence of MOF on the mechanical and thermal properties of both polymers was investigated by tensile tests and differential scanning calorimetry, respectively. The MOF loading in Pebax®1657 increased the ideal H2/N2 selectivity from 6 to 8 thanks to an increased H2 permeability. In general, the MOF had little effect on the Pebax®165 membranes because an increase in gas solubility was neutralized by an equivalent decrease in effective diffusivity. Instead, the addition of MOF to PEEK-WC increases the ideal CO2/CH4 selectivity from 30 to ~48 thanks to an increased CO2 permeability (from 6 to 48 Barrer). The increase in CO2 permeability and CO2/CH4 selectivity is maintained under mixed gas conditions.

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.

Synthesis of Potassium Ionic Sieve Membrane and its Selectivity to Potassium Ion in Seawater

2010 ◽  
Vol 178 ◽  
pp. 300-307 ◽  
Author(s):  
Jun Sheng Yuan ◽  
Fei Li ◽  
Hui Ru Han ◽  
Zhi Yong Ji
Keyword(s):  
Hydrothermal Synthesis ◽  
Gas Permeability ◽  
Knudsen Diffusion ◽  
Potassium Ion ◽  
Zeolite Membranes ◽  
Al2o3 Tube ◽  
Separation Factors ◽  
Α Al2o3 ◽  
High Separation ◽  
The Ideal

Potassium ionic sieve membrane was synthesized on porous α-Al2O3 tube support by the hydrothermal synthesis. The zeolite membranes were characterized by means of XRD and SEM. And the single-gas permeability through the membranes and selectivity to K+, Na+, Ca2+, Mg2+ were measured. The results show that the ideal separation factor is 3.68, which is close to Knudsen diffusion ratio 3.74 for H2/N2; the separation factors of the potassium ionic sieve membrane are , , respectively, indicating its high separation selectivity to potassium ion.

Evaluation of the ideal selectivity and the performance of selectrodialysis by using TFC ion exchange membranes

2019 ◽  
Vol 582 ◽  
pp. 236-245 ◽  
Author(s):  
Wenguang Wang ◽  
Ru Liu ◽  
Ming Tan ◽  
Haixiang Sun ◽  
Q. Jason Niu ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Membranes ◽  
Ideal Selectivity ◽  
The Ideal

scholarly journals Highly Permeable Matrimid®/PIM-EA(H2)-TB Blend Membrane for Gas Separation

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 46 ◽  
Author(s):  
Elisa Esposito ◽  
Irene Mazzei ◽  
Marcello Monteleone ◽  
Alessio Fuoco ◽  
Mariolino Carta ◽  
...  
Keyword(s):  
Diffusion Coefficients ◽  
Gas Transport ◽  
Gas Permeability ◽  
Time Lag ◽  
Gas Diffusion ◽  
Gas Permeation ◽  
Spectrometric Analysis ◽  
Competitive Sorption ◽  
Transport Parameters ◽  
Mixed Gas

The effect on the gas transport properties of Matrimid®5218 of blending with the polymer of intrinsic microporosity PIM-EA(H2)-TB was studied by pure and mixed gas permeation measurements. Membranes of the two neat polymers and their 50/50 wt % blend were prepared by solution casting from a dilute solution in dichloromethane. The pure gas permeability and diffusion coefficients of H2, He, O2, N2, CO2 and CH4 were determined by the time lag method in a traditional fixed volume gas permeation setup. Mixed gas permeability measurements with a 35/65 vol % CO2/CH4 mixture and a 15/85 vol % CO2/N2 mixture were performed on a novel variable volume setup with on-line mass spectrometric analysis of the permeate composition, with the unique feature that it is also able to determine the mixed gas diffusion coefficients. It was found that the permeability of Matrimid increased approximately 20-fold with the addition of 50 wt % PIM-EA(H2)-TB. Mixed gas permeation measurements showed a slightly stronger pressure dependence for selectivity of separation of the CO2/CH4 mixture as compared to the CO2/N2 mixture, particularly for both the blended membrane and the pure PIM. The mixed gas selectivity was slightly higher than for pure gases, and although N2 and CH4 diffusion coefficients strongly increase in the presence of CO2, their solubility is dramatically reduced as a result of competitive sorption. A full analysis is provided of the difference between the pure and mixed gas transport parameters of PIM-EA(H2)-TB, Matrimid®5218 and their 50:50 wt % blend, including unique mixed gas diffusion coefficients.

scholarly journals Evaluation of the Properties, Gas Permeability, and Selectivity of Mixed Matrix Membrane Based on Polysulfone Polymer Matrix Incorporated with KIT-6 Silica

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1732 ◽  
Author(s):  
Sie Hao Ding ◽  
Tiffany Yit Siew Ng ◽  
Thiam Leng Chew ◽  
Pei Ching Oh ◽  
Abdul Latif Ahmad ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Polymer Matrix ◽  
Pressure Difference ◽  
Gas Permeability ◽  
Gas Permeation ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix Membrane ◽  
Mixed Matrix ◽  
Carbon Dioxide Co2 ◽  
The Ideal

Mixed matrix membranes (MMMs) separation is a promising technology for gas permeation and separation involving carbon dioxide (CO2). However, finding a suitable type of filler for the formation of defect-free MMMs with enhancement in gas permeability remains a challenge. Current study focuses on synthesis of KIT-6 silica and followed by the incorporation of KIT-6 silica as filler into polysulfone (PSF) polymer matrix to fabricate MMMs, with filler loadings of 0–8 wt %. The effect of KIT-6 incorporation on the properties of the fabricated MMMs was evaluated via different characterization techniques. The MMMs were investigated for gas permeability and selectivity with pressure difference of 5 bar at 25 °C. KIT-6 with typical rock-like morphology was synthesized. Incorporation of 2 wt % of KIT-6 into PSF matrix produced MMMs with no void. When KIT-6 loadings in the MMMs were increased from 0 to 2 wt %, the CO2 permeability increased by ~48%, whereas the ideal CO2/CH4 selectivity remained almost constant. However, when the KIT-6 loading in PSF polymer matrix was more than 2 wt %, the formation of voids in the MMMs increased the CO2 permeability but sacrificed the ideal CO2/CH4 selectivity. In current study, KIT-6 was found to be potential filler for PSF matrix under controlled KIT-6 loading for gas permeation.

Mixed gas transport study through polymeric membranes

1998 ◽  
Vol 141 (1) ◽  
pp. 45-63 ◽  
Author(s):  
Sukhtej S Dhingra ◽  
Eva Marand
Keyword(s):  
Gas Transport ◽  
Polymeric Membranes ◽  
Mixed Gas ◽  
Transport Study

scholarly journals Ultra-selective defect-free interfacially polymerized molecular sieve thin-film composite membranes for H2 purification

2018 ◽  
Vol 6 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Z. Ali ◽  
F. Pacheco ◽  
E. Litwiller ◽  
Y. Wang ◽  
Y. Han ◽  
...  
Keyword(s):  
Thin Film ◽  
Molecular Sieve ◽  
State Of The Art ◽  
Composite Membranes ◽  
Polymeric Membranes ◽  
Mixed Gas ◽  
Film Composite ◽  
Thin Film Composite

Ultrathin, defect-free thin-film polyamide composite membranes developed for H2/CO2 separation exhibit mixed-gas performance far exceeding all state-of-the-art polymeric membranes.

Sign in / Sign up

Export Citation Format

Share Document