scholarly journals Generalizability of the Time-Lag Method for Mixed-Matrix Membranes: Does One Method Fit It All?

2021 ◽  
Author(s):  
Haoyu Wu ◽  
Zheng Cao ◽  
Boguslaw Kruczek ◽  
Jules Thibault
Keyword(s):  
Time Lag ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Matrix Membranes

scholarly journals CO2 Selective, Zeolitic Imidazolate Framework-7 Based Polymer Composite Mixed-Matrix Membranes

2018 ◽  
Vol 7 (3) ◽  
pp. 1 ◽  
Author(s):  
Tina Chakrabarty ◽  
Pradeep Neelakanda ◽  
Klaus-Viktor Peinemann
Keyword(s):  
Metal Organic Framework ◽  
Time Lag ◽  
Morphological Characterization ◽  
Mixed Matrix Membranes ◽  
Co2 Removal ◽  
Hybrid Membranes ◽  
Mixed Matrix ◽  
Zeolitic Imidazolate Framework ◽  
Custom Made ◽  
Matrix Membranes

CO2 removal is necessary to mitigate the effects of global warming but it is a challenging process to separate CO2 from natural gas, biogas, and other gas streams. Development of hybrid membranes by use of polymers and metal-organic framework (MOF) particles is a viable option to overcome this challenge. A ZIF-7 nano-filler that was synthesized in our lab was embedded into a designed polymer matrix at various loadings and the performance of the mixed matrix membranes was evaluated in terms of gas permeance and selectivity. Hybrid membranes with various loadings (20, 30 and 40 wt%) were developed and tested at room temperature by a custom made time lag equipment and a jump in selectivity was observed when compared with the pristine polymer. A commercially attractive region for the selectivity CO2 over CH4 was achieved with a selectivity of 39 for 40 wt% particle loading. An increase in selectivity was observed with the increase of ZIF-7 loadings. Best performance was seen at 40% ZIF-7 loaded membrane with an ideal selectivity of 39 for CO2 over CH4. The obtained selectivity was 105% higher for CO2 over CH4 than the selectivity of the pristine polymer with a slight decrease in permeance. Morphological characterization of such developed membranes showed an excellent compatibility between the polymer and particle adhesion.

scholarly journals Gas Transport in Mixed Matrix Membranes: Two Methods for Time Lag Determination

Computation ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 28 ◽  
Author(s):  
Alessio Fuoco ◽  
Marcello Monteleone ◽  
Elisa Esposito ◽  
Rosaria Bruno ◽  
Jesús Ferrando-Soria ◽  
...  
Keyword(s):  
Transport Properties ◽  
Gas Transport ◽  
Time Lag ◽  
Effective Diffusion ◽  
Gas Permeation ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Fitting Procedure ◽  
Matrix Membranes

The most widely used method to measure the transport properties of dense polymeric membranes is the time lag method in a constant volume/pressure increase instrument. Although simple and quick, this method provides only relatively superficial, averaged data of the permeability, diffusivity, and solubility of gas or vapor species in the membrane. The present manuscript discusses a more sophisticated computational method to determine the transport properties on the basis of a fit of the entire permeation curve, including the transient period. The traditional tangent method and the fitting procedure were compared for the transport of six light gases (H2, He, O2, N2, CH4, and CO2) and ethane and ethylene in mixed matrix membranes (MMM) based on Pebax®1657 and the metal–organic framework (MOF) CuII2(S,S)-hismox·5H2O. Deviations of the experimental data from the theoretical curve could be attributed to the particular MOF structure, with cavities of different sizes. The fitting procedure revealed two different effective diffusion coefficients for the same gas in the case of methane and ethylene, due to the unusual void morphology in the MOFs. The method was furthermore applied to mixed gas permeation in an innovative constant-pressure/variable-volume setup with continuous analysis of the permeate composition by an on-line mass-spectrometric residual gas analyzer. This method can provide the diffusion coefficient of individual gas species in a mixture, during mixed gas permeation experiments. Such information was previously inaccessible, and it will greatly enhance insight into the mixed gas transport in polymeric or mixed matrix membranes.

Magnetic mixed matrix membranes in air separation

2014 ◽  
Vol 68 (10) ◽  
Author(s):  
Aleksandra Rybak ◽  
Gabriela Dudek ◽  
Monika Krasowska ◽  
Anna Strzelewicz ◽  
Zbigniew Grzywna ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Gas Permeability ◽  
Transport Coefficients ◽  
Time Lag ◽  
Filler Loading ◽  
Air Separation ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Pressure System ◽  
Matrix Membranes

AbstractEthylcellulose (EC) or linear polyimide (LPI) and magnetic neodymium powder particles MQP-14-12 were used for the preparation of inorganic-organic hybrid membranes. For all the membranes, N2, O2 and air permeability were examined. Mass transport coefficients were determined using the Time Lag System based on dynamic experiments in a constant pressure system. The results showed that the membrane permeation properties were improved by the addition of magnetic neodymium particles to the polymer matrix. The magnetic ethylcellulose and polyimide membranes exhibited higher gas permeability and diffusivity, while their permeability selectivity and solubility were either unchanged or slightly increased. Polyimide mixed matrix membranes were characterised by a higher thermal and mechanical stability, larger filler loading, better magnetic properties and reasonable selectivity in the air separation.

scholarly journals PEEK–WC-Based Mixed Matrix Membranes Containing Polyimine Cages for Gas Separation

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5557
Author(s):  
Marcello Monteleone ◽  
Riccardo Mobili ◽  
Chiara Milanese ◽  
Elisa Esposito ◽  
Alessio Fuoco ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Gas Separation ◽  
Gas Permeability ◽  
Time Lag ◽  
Mixed Matrix Membranes ◽  
Filler Materials ◽  
Separation Performance ◽  
Mixed Matrix ◽  
Neat Polymer ◽  
Matrix Membranes

Membrane-based processes are taking a more and more prominent position in the search for sustainable and energy-efficient gas separation applications. It is known that the separation performance of pure polymers may significantly be improved by the dispersion of suitable filler materials in the polymer matrix, to produce so-called mixed matrix membranes. In the present work, four different organic cages were dispersed in the poly(ether ether ketone) with cardo group, PEEK-WC. The m-xylyl imine and furanyl imine-based fillers yielded mechanically robust and selective films after silicone coating. Instead, poor dispersion of p-xylyl imine and diphenyl imine cages did not allow the formation of selective films. The H2, He, O2, N2, CH4, and CO2 pure gas permeability of the neat polymer and the MMMs were measured, and the effect of filler was compared with the maximum limits expected for infinitely permeable and impermeable fillers, according to the Maxwell model. Time lag measurements allowed the calculation of the diffusion coefficient and demonstrated that 20 wt % of furanyl imine cage strongly increased the diffusion coefficient of the bulkier gases and decreased the diffusion selectivity, whereas the m-xylyl imine cage slightly increased the diffusion coefficient and improved the size-selectivity. The performance and properties of the membranes were discussed in relation to their composition and morphology.

Long-Term Stable Metal Organic Framework (MOF) Based Mixed Matrix Membranes for Ultrafiltration

2020 ◽  
Author(s):  
Muayad Al-shaeli ◽  
Stefan J. D. Smith ◽  
Shanxue Jiang ◽  
Huanting Wang ◽  
Kaisong Zhang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Mixed Matrix Membranes ◽  
Recovery Ratio ◽  
Mixed Matrix ◽  
Water Contact ◽  
Membrane Performance ◽  
Metal Organic ◽  
Matrix Membranes

<p>In this study, novel <a>mixed matrix polyethersulfone (PES) membranes</a> were synthesized by using two different kinds of metal organic frameworks (MOFs), namely UiO-66 and UiO-66-NH<sub>2</sub>. The composite membranes were characterised by SEM, EDX, FTIR, PXRD, water contact angle, porosity, pore size, etc. Membrane performance was investigated by water permeation flux, flux recovery ratio, fouling resistance and anti-fouling performance. The stability test was also conducted for the prepared mixed matrix membranes. A higher reduction in the water contact angle was observed after adding both MOFs to the PES and sulfonated PES membranes compared to pristine PES membranes. An enhancement in membrane performance was observed by embedding the MOF into PES membrane matrix, which may be attributed to the super-hydrophilic porous structure of UiO-66-NH<sub>2</sub> nanoparticles and hydrophilic structure of UiO-66 nanoparticles that could accelerate the exchange rate between solvent and non-solvent during the phase inversion process. By adding the MOFs into PES matrix, the flux recovery ratio was increased greatly (more than 99% for most mixed matrix membranes). The mixed matrix membranes showed higher resistance to protein adsorption compared to pristine PES membranes. After immersing the membranes in water for 3 months, 6 months and 12 months, both MOFs were stable and retained their structure. This study indicates that UiO-66 and UiO-66-NH<sub>2</sub> are great candidates for designing long-term stable mixed matrix membranes with higher anti-fouling performance.</p>

Porous covalent triazine piperazine polymer (CTPP)/PEBAX mixed matrix membranes for CO2/N2 and CO2/CH4 separations

2019 ◽  
Vol 591 ◽  
pp. 117348 ◽  
Author(s):  
Roshni L. Thankamony ◽  
Xiang Li ◽  
Swapan K. Das ◽  
Mayur M. Ostwal ◽  
Zhiping Lai
Keyword(s):  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Matrix Membranes

Mixed matrix membranes with molecular-interaction-driven tunable free volumes for efficient bio-fuel recovery

2015 ◽  
Vol 3 (8) ◽  
pp. 4510-4521 ◽  
Author(s):  
Gongping Liu ◽  
Wei-Song Hung ◽  
Jie Shen ◽  
Qianqian Li ◽  
Yun-Hsuan Huang ◽  
...  
Keyword(s):  
Polymer Chain ◽  
Molecular Interactions ◽  
Molecular Interaction ◽  
Chain Conformation ◽  
Mixed Matrix Membranes ◽  
Mixed Matrix ◽  
Polymer Chain Conformation ◽  
Matrix Membranes

Molecular interactions were constructed to control polymer chain conformation to fabricate mixed matrix membranes with tunable free volumes, exhibiting simultaneously improved butanol permeability and selectivity.

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