scholarly journals Thickness Effect on CO2/N2 Separation in Double Layer Pebax-1657®/PDMS Membranes

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 121 ◽  
Author(s):  
Roman Selyanchyn ◽  
Miho Ariyoshi ◽  
Shigenori Fujikawa
Keyword(s):  
Double Layer ◽  
Gas Permeability ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Thickness Effect ◽  
Organic Polymer ◽  
Porous Support ◽  
Model Predictions ◽  
Layer Membrane ◽  
In Series

The effect of thickness in multilayer thin-film composite membranes on gas permeation has received little attention to date, and the gas permeances of the organic polymer membranes are believed to increase by membrane thinning. Moreover, the performance of defect-free layers with known gas permeability can be effectively described using the classical resistance in series models to predict both permeance and selectivity of the composite membrane. In this work, we have investigated the Pebax®-MH1657/PDMS double layer membrane as a selective/gutter layer combination that has the potential to achieve sufficient CO2/N2 selectivity and permeance for efficient CO2 and N2 separation. CO2 and N2 transport through membranes with different thicknesses of two layers has been investigated both experimentally and with the utilization of resistance in series models. Model prediction for permeance/selectivity corresponded perfectly with experimental data for the thicker membranes. Surprisingly, a significant decrease from model predictions was observed when the thickness of the polydimethylsiloxane (PDMS) (gutter layer) became relatively small (below 2 µm thickness). Material properties changed at low thicknesses—surface treatments and influence of porous support are discussed as possible reasons for observed deviations.

Ion Beam Irradiation—An Efficient Method to Modify The Subnanometer Scale Microstructure of Polymers In A Controlled Way

1998 ◽  
Vol 540 ◽  
Author(s):  
Xinglong Xu ◽  
M. R. Coleman ◽  
U. Myler ◽  
P. J. Simpson
Keyword(s):  
Ion Irradiation ◽  
Gas Permeability ◽  
Ion Beam ◽  
Composite Membranes ◽  
Positron Annihilation Spectroscopy ◽  
Gas Permeation ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Application Potential ◽  
Promising Application

AbstractThe microstructural evolution of polymers induced by ion beam irradiation was investigated using gas permeation measurements with different molecule size gases and positron annihilation spectroscopy (PAS) using variable-energy positron. Simultaneous large increases in gas permeability and permselectivity of polymer-ceramic composite membranes modified by 180 keV H+ ion irradiation indicated that ion irradiation of polymers can modify the microstructure of polymer at sub-nanometer level in a controlled way. PAS results were consistent with the gas permeation results. The results of this work demonstrated ion beam irradiation has a promising application potential in the separation industry.

scholarly journals Characteristics of Gas Permeation Behaviour in Multilayer Thin Film Composite Membranes for CO2 Separation

Membranes ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 22 ◽  
Author(s):  
Jelena Lillepärg ◽  
Sabrina Breitenkamp ◽  
Sergey Shishatskiy ◽  
Jan Pohlmann ◽  
Jan Wind ◽  
...  
Keyword(s):  
Thin Film ◽  
Mass Transfer ◽  
Time Lag ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Porous Support ◽  
Film Composite ◽  
Thin Film Composite ◽  
Free Volume Model ◽  
The Individual

Porous, porous/gutter layer and porous/gutter layer/selective layer types of membranes were investigated for their gas transport properties in order to derive an improved description of the transport performance of thin film composite membranes (TFCM). A model describing the individual contributions of the different layers’ mass transfer resistances was developed. The proposed method allows for the prediction of permeation behaviour with standard deviations (SD) up to 10%. The porous support structures were described using the Dusty Gas Model (based on the Maxwell–Stefan multicomponent mass transfer approach) whilst the permeation in the dense gutter and separation layers was described by applicable models such as the Free-Volume model, using parameters derived from single gas time lag measurements. The model also accounts for the thermal expansion of the dense layers at pressure differences below 100 kPa. Using the model, the thickness of a silicone-based gutter layer was calculated from permeation measurements. The resulting value differed by a maximum of 30 nm to the thickness determined by scanning electron microscopy.

Preparation and Characterization of AgA Zeolite/Polysulfone Membranes

2012 ◽  
Vol 549 ◽  
pp. 401-405
Author(s):  
Tian Ming Zhang ◽  
Zhen Huang ◽  
Xiao Hong Zhang ◽  
Li Ying Guo
Keyword(s):  
Ion Exchange ◽  
Gas Permeability ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Silver Ion ◽  
Interfacial Interactions ◽  
Polysulfone Membrane ◽  
Characterization Methods ◽  
Permeation Test

In present study, a few polysulfone composite membranes with the introduction of silver ion-exchange treated zeolite were prepared and evaluated by several characterization methods. Regularly-ordered zeolite particles were generally finely dispersed in the continuous PSF phase with appreciated organic-inorganic interfacial interactions as reflected by SEM and FTIR results. Gas permeation test shows that after incorporating zeolite the polysulfone membrane exhibits significantly decreased gas permeability for H2, N2, and CO2 whereas they show increased permselectivity for CO2/N2, H2/CO2 and H2/N2 gas pairs as compared to neat polysulfone membrane.

Free volume, gas permeation, and proton conductivity in MIL-101-SO3H/Nafion composite membranes

2019 ◽  
Vol 21 (47) ◽  
pp. 25982-25992
Author(s):  
Chongshan Yin ◽  
Chunqing He ◽  
Qicheng Liu ◽  
Bangyun Xiong ◽  
Xiaowei Zhang ◽  
...  
Keyword(s):  
Free Volume ◽  
Proton Conductivity ◽  
Gas Permeability ◽  
Composite Membranes ◽  
Gas Permeation ◽  
Gas Molecules ◽  
Volume Size

The influence of free volume size on the gas permeability of MIL-101-SO3H/Nafion composite membranes is closely related to the size of the particular gas molecules.

DEPOSITION OF DOUBLE-LAYER COATINGS FOR PREPARING COMPOSITE MEMBRANES WITH SUPERHYDROPHOBIC PROPERTIES

2019 ◽  
Vol 23 (1) ◽  
pp. 77-96 ◽  
Author(s):  
Liubov I. Kravets ◽  
Maxim A. Yarmolenko ◽  
Alexander A. Rogachev ◽  
Radmir V. Gainutdinov ◽  
Vladimir A. Altynov ◽  
...  
Keyword(s):  
Double Layer ◽  
Composite Membranes

Theoretical Principles of Streaming Current Detection

1989 ◽  
Vol 21 (6-7) ◽  
pp. 443-453 ◽  
Author(s):  
S. K. Dentel ◽  
K. M. Kingery
Keyword(s):  
Velocity Profile ◽  
Electrophoretic Mobility ◽  
Double Layer ◽  
Initial Attempt ◽  
Streaming Current ◽  
Coagulant Dosage ◽  
Model Predictions ◽  
Double Layer Model ◽  
Simplifying Assumptions ◽  
Current Detection

In spite of the increased use of streaming current detectors (SCDs) as a means of monitoring and/or controlling coagulant dosage, knowledge regarding fundamental workings is incomplete. This paper provides an initial attempt at predicting and verifying functioning compared to electrophoretic mobility. The instrument's components -- the sensor and the signal processor -- are first described. Equations modelling electro-double layer behavior in its sensor are then developed. Simplifying assumptions include the use of a capacitance model of the double layer and a triangular velocity profile for fluid within the sensor's annulus. More complex modelling approaches are also suggested which incorporate the Gouy-Chapman electro-double layer model and an exact solution for the velocity profile. Experimental results confirm predictions of the simplified model under conditions of low potential. A monotonic relationship exists between streaming current electrophoretic mobility, which is required for its use as a control parameter. Deviations from model predictions are suggested to be due to charge characteristics of the sensor surfaces themselves.

scholarly journals Research and application progress of lignin-based composite membrane

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Youjing Li ◽  
Fen Li ◽  
Ying Yang ◽  
Baocai Ge ◽  
Fanzhu Meng
Keyword(s):  
Environmental Pollution ◽  
Raw Materials ◽  
Waste Product ◽  
Functional Materials ◽  
Polymeric Materials ◽  
Composite Membranes ◽  
Organic Polymer ◽  
Future Research ◽  
Sustainable Resources ◽  
New Perspective

Abstract In view of the serious environmental pollution, which is the greatest problem the world is facing, and the continuous consumption of raw materials, it is imminent to search for green and sustainable resources. Lignin is an organic polymer that exists widely in nature, and if it can be transformed from traditional low-value waste product with low range of applications to functional materials with high application prospects, it can be of great significance to alleviate environmental pollution and shortage of fossil resources. One of the functional applications of lignin involves its use to fabricate composite with other polymeric materials, which can then be used to prepare membrane materials. This review summarizes the recent research and application progress of combining lignin with polypropylene, polyvinyl alcohol, starch, cellulose, chitosan, and other polymeric materials to prepare composite membranes; and summarizes the future development direction of lignin-based composite membranes. We hope this review may provide a new perspective to the understanding of lignin-based composite membranes and a useful reference for future research.

Multi-cycle reversible control of gas permeability in thin film composite membranes via efficient UV-induced reactions

2021 ◽  
Vol 57 (27) ◽  
pp. 3391-3394
Author(s):  
Abdalrahman U. Alrayyes ◽  
Ze-Xian Low ◽  
Huanting Wang ◽  
Kei Saito
Keyword(s):  
Thin Film ◽  
Polymer Coating ◽  
Gas Permeability ◽  
Composite Membranes ◽  
Polymer Structure ◽  
Film Composite ◽  
Thin Film Composite ◽  
Thin Polymer

This communication reports the use of light to reversibly constrict or ease the flow of oxygen through a very thin polymer coating. This is achievable by reversibly changing the polymer structure from a dense and rigid film to a loose and soft film.

scholarly journals Gas Permeation Through Single-Crystal ZIF-8 Membranes

2019 ◽  
Author(s):  
Chen Chen ◽  
Aydin Ozcan ◽  
A. Ozgur Yazaydin ◽  
Bradley Ladewig
Keyword(s):  
Single Crystal ◽  
Grain Boundaries ◽  
Gas Permeability ◽  
Metal Organic Framework ◽  
Gas Permeation ◽  
Microstructural Feature ◽  
Polycrystalline Metal ◽  
Transmission Electron ◽  
Metal Organic ◽  
Separation Performances

<b>Abstract</b><div>Grain boundaries are an unavoidable microstructural feature in intergrown polycrystalline metal-organic framework (MOF) membranes. They have been suspected to be less size-selective than a MOF’s micropores, resulting in suboptimal separation performances – a speculation recently confirmed by transmission electron microscopy of MOF ZIF-8. Single-crystal membranes, without grain boundaries, should confine mass transport to micropores and reflect the intrinsic selectivity of the porous material. Here, we demonstrate the feasibility of fabricating single-crystal MOF membranes and directly measuring gas permeability through such a membrane using ZIF-8 as an exemplary MOF. Our single-crystal ZIF-8 membranes achieved ideal selectivities up to 28.9, 10.0, 40.1 and 3.6 for gas pairs CO<sub>2</sub>/N<sub>2</sub>, CO<sub>2</sub>/CH<sub>4</sub>, He/CH<sub>4</sub> and CH<sub>4</sub>/N<sub>2</sub> respectively, much higher than or reversely selective to over 20 polycrystalline ZIF-8 membranes, unequivocally proving the non-selectivity of grain boundaries. The permeability trend obtained in single-crystal membranes aligned with a force field that had been validated against multiple empirical adsorption isotherms.<br></div>

scholarly journals Porous Medium Equation in Graphene Oxide Membrane: Nonlinear Dependence of Permeability on Pressure Gradient Explained

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 665
Author(s):  
Lukáš Mrazík ◽  
Pavel Kříž
Keyword(s):  
Porous Medium ◽  
Graphene Oxide ◽  
Governing Equation ◽  
Pressure Difference ◽  
Gas Permeability ◽  
Porous Medium Equation ◽  
Gas Permeation ◽  
Nonlinear Dependence ◽  
Medium Equation ◽  
Oxide Membrane

Membrane performance in gas separation is quantified by its selectivity, determined as a ratio of measured gas permeabilities of given gases at fixed pressure difference. In this manuscript a nonlinear dependence of gas permeability on pressure difference observed in the measurements of gas permeability of graphene oxide membrane on a manometric integral permeameter is reported. We show that after reasoned assumptions and simplifications in the mathematical description of the experiment, only static properties of any proposed governing equation can be studied, in order to analyze the permeation rate for different pressure differences. Porous Medium Equation is proposed as a suitable governing equation for the gas permeation, as it manages to predict a nonlinear behavior which is consistent with the measured data. A coefficient responsible for the nonlinearity, the polytropic exponent, is determined to be gas-specific—implications on selectivity are discussed, alongside possible hints to a deeper physical interpretation of its actual value.

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