Special Issue "Membrane Transport Modeling"

A special issue of Membranes (ISSN 2077-0375).

Deadline for manuscript submissions: closed (30 June 2017)

Special Issue Editor

Guest Editor
Prof. Dr. Spas D. Kolev

School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia
Website | E-Mail
Phone: +61 3 83447931
Interests: ion-exchange and liquid membranes, membrane applications in passive sampling, flow analysis, water treatment, chemical sensing, synthesis of metal nanoparticles

Special Issue Information

Dear Colleagues,

Nearly a century ago, Daynes (1920) and Sakai (1922) pioneered the analysis of unsteady-state diffusive transport in single sheets and laminates. Since then, applied scientists have paired conservation equations with Fick’s Law and other phenomenological relations to formulate mathematical models of steady-state and unsteady-state membrane processes, designed experiments to test them, and extracted parameters from the data. Validated models have enabled rational design of a wide array of membrane-based industrial, biomedical and environmentally protective processes and devices.

In recent years, the rapid growth in digital computation capacity and the availability of Molecular Dynamics (MD) software have spurred microscopic transport modeling – the á priori prediction of permeation rates based on rigorous calculation of the specific interactions of various membrane materials with atoms, ions and molecules.

This Special Issue will focus on recent progress in the development and practical application of (a) microscopic membrane transport models; (b) macroscopic membrane transport models which account for the coupling of permeation to, or dependence of permeance and selectivity upon, factors including but not limited to: chemical reactions, heat and viscoelastic effects, electrical and other force fields, external transport resistances and membrane heterogeneity; and (c) mathematical analyses which facilitate inference of model parameters from experimental data.

Daynes, H.A. (1920) “The process of diffusion through a rubber membrane,” Proc. Royal Soc. London A, 97, 285-307.
Sakai, S. (1922) “Linear conduction of heat through a series of connected rods,” Sci. Rep. Tohoku Imperial Univ., Ser. I (Math, Phys., Chem.), 11, 351- 378.

Research articles as well as reviews are invited. If you are uncertain of the suitability of your work to this Special Issue, I encourage you to contact me directly ([email protected]).

Dr. Jerry H. Meldon
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Membrane transport
  • Mathematical model
  • Model
  • Mass balances
  • Fick’s Law
  • Permeation
  • Permeance
  • Selectivity
  • Computational capacity
  • Phenomenological relations
  • Sheets
  • Laminates
  • Unsteady-state
  • Steady-state
  • Processes
  • Devices
  • Modeling
  • Macroscopic
  • Microscopic
  • Molecular Dynamics software
  • Model development
  • Model validation
  • Experiments
  • Parameters
  • Rational design
  • á priori prediction
  • Materials
  • Atoms
  • Ions
  • Molecules
  • Interactions
  • Coupling
  • Chemical reactions
  • Heat effects
  • Electrical fields
  • Force fields
  • External transport resistance
  • Heterogeneity
  • Analyses
  • Experimental Data

Published Papers (5 papers)

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Research

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Open AccessArticle Modeling and Design Optimization of Multifunctional Membrane Reactors for Direct Methane Aromatization
Received: 8 July 2017 / Revised: 9 August 2017 / Accepted: 15 August 2017 / Published: 29 August 2017
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Abstract
Due to the recent increase of natural gas production in the U.S., utilizing natural gas for higher-value chemicals has become imperative. Direct methane aromatization (DMA) is a promising process used to convert methane to benzene, but it is limited by low conversion of [...] Read more.
Due to the recent increase of natural gas production in the U.S., utilizing natural gas for higher-value chemicals has become imperative. Direct methane aromatization (DMA) is a promising process used to convert methane to benzene, but it is limited by low conversion of methane and rapid catalyst deactivation by coking. Past work has shown that membrane separation of the hydrogen produced in the DMA reactions can dramatically increase the methane conversion by shifting the equilibrium toward the products, but it also increases coke production. Oxygen introduction into the system has been shown to inhibit this coke production while not inhibiting the benzene production. This paper introduces a novel mathematical model and design to employ both methods in a multifunctional membrane reactor to push the DMA process into further viability. Multifunctional membrane reactors, in this case, are reactors where two different separations occur using two differently selective membranes, on which no systems studies have been found. The proposed multifunctional membrane design incorporates a hydrogen-selective membrane on the outer wall of the reaction zone, and an inner tube filled with airflow surrounded by an oxygen-selective membrane in the middle of the reactor. The design is shown to increase conversion via hydrogen removal by around 100%, and decrease coke production via oxygen addition by 10% when compared to a tubular reactor without any membranes. Optimization studies are performed to determine the best reactor design based on methane conversion, along with coke and benzene production. The obtained optimal design considers a small reactor (length = 25 cm, diameter of reaction tube = 0.7 cm) to subvert coke production and consumption of the product benzene as well as a high permeance (0.01 mol/s·m2·atm1/4) through the hydrogen-permeable membrane. This modeling and design approach sets the stage for guiding further development of multifunctional membrane reactor models and designs for natural gas utilization and other chemical reaction systems. Full article
(This article belongs to the Special Issue Membrane Transport Modeling)
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Open AccessArticle Thermodynamic Modeling of Gas Transport in Glassy Polymeric Membranes
Received: 27 July 2017 / Revised: 10 August 2017 / Accepted: 16 August 2017 / Published: 19 August 2017
Cited by 3 | PDF Full-text (6607 KB) | HTML Full-text | XML Full-text
Abstract
Solubility and permeability of gases in glassy polymers have been considered with the aim of illustrating the applicability of thermodynamically-based models for their description and prediction. The solubility isotherms are described by using the nonequilibrium lattice fluid (NELF) (model, already known to be [...] Read more.
Solubility and permeability of gases in glassy polymers have been considered with the aim of illustrating the applicability of thermodynamically-based models for their description and prediction. The solubility isotherms are described by using the nonequilibrium lattice fluid (NELF) (model, already known to be appropriate for nonequilibrium glassy polymers, while the permeability isotherms are described through a general transport model in which diffusivity is the product of a purely kinetic factor, the mobility coefficient, and a thermodynamic factor. The latter is calculated from the NELF model and mobility is considered concentration-dependent through an exponential relationship containing two parameters only. The models are tested explicitly considering solubility and permeability data of various penetrants in three glassy polymers, PSf, PPh and 6FDA-6FpDA, selected as the reference for different behaviors. It is shown that the models are able to calculate the different behaviors observed, and in particular the permeability dependence on upstream pressure, both when it is decreasing as well as when it is increasing, with no need to invoke the onset of additional plasticization phenomena. The correlations found between polymer and penetrant properties with the two parameters of the mobility coefficient also lead to the predictive ability of the transport model. Full article
(This article belongs to the Special Issue Membrane Transport Modeling)
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Open AccessArticle The Effect of the Pore Entrance on Particle Motion in Slit Pores: Implications for Ultrathin Membranes
Received: 30 June 2017 / Revised: 25 July 2017 / Accepted: 31 July 2017 / Published: 10 August 2017
Cited by 2 | PDF Full-text (3388 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Membrane rejection models generally neglect the effect of the pore entrance on intrapore particle transport. However, entrance effects are expected to be particularly important with ultrathin membranes, where membrane thickness is typically comparable to pore size. In this work, a 2D model was [...] Read more.
Membrane rejection models generally neglect the effect of the pore entrance on intrapore particle transport. However, entrance effects are expected to be particularly important with ultrathin membranes, where membrane thickness is typically comparable to pore size. In this work, a 2D model was developed to simulate particle motion for spherical particles moving at small Re and infinite Pe from the reservoir outside the pore into a slit pore. Using a finite element method, particles were tracked as they accelerated across the pore entrance until they reached a steady velocity in the pore. The axial position in the pore where particle motion becomes steady is defined as the particle entrance length (PEL). PELs were found to be comparable to the fluid entrance length, larger than the pore size and larger than the thickness typical of many ultrathin membranes. Results also show that, in the absence of particle diffusion, hydrodynamic particle–membrane interactions at the pore mouth result in particle “funneling” in the pore, yielding cross-pore particle concentration profiles focused at the pore centerline. The implications of these phenomena on rejection from ultrathin membranes are examined. Full article
(This article belongs to the Special Issue Membrane Transport Modeling)
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Open AccessFeature PaperArticle Influence of Membrane Equivalent Weight and Reinforcement on Ionic Species Crossover in All-Vanadium Redox Flow Batteries
Received: 3 May 2017 / Revised: 23 May 2017 / Accepted: 2 June 2017 / Published: 6 June 2017
Cited by 8 | PDF Full-text (4232 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
One of the major sources of lost capacity in all-vanadium redox flow batteries (VRFBs) is the undesired transport (usually called crossover) of water and vanadium ions through the ion-exchange membrane. In this work, an experimental assessment of the impact of ion-exchange membrane properties [...] Read more.
One of the major sources of lost capacity in all-vanadium redox flow batteries (VRFBs) is the undesired transport (usually called crossover) of water and vanadium ions through the ion-exchange membrane. In this work, an experimental assessment of the impact of ion-exchange membrane properties on vanadium ion crossover and capacity decay of VRFBs has been performed. Two types of cationic membranes (non-reinforced and reinforced) with three equivalent weights of 800, 950 and 1100 g·mol−1 were investigated via a series of in situ performance and capacity decay tests along with ex situ vanadium crossover measurement and membrane characterization. For non-reinforced membranes, increasing the equivalent weight (EW) from 950 to 1100 g·mol−1 decreases the V(IV) permeability by ~30%, but increases the area-specific resistance (ASR) by ~16%. This increase in ASR and decrease in V(IV) permeability was accompanied by increased through-plane membrane swelling. Comparing the non-reinforced with reinforced membranes, membrane reinforcement increases ASR, but V(IV) permeability decreases. It was also shown that there exists a monotonic correlation between the discharge capacity decay over long-term cycling and V(IV) permeability values. Thus, V(IV) permeability is considered a representative diagnostic for assessing the overall performance of a particular ion-exchange membrane with respect to capacity fade in a VRFB. Full article
(This article belongs to the Special Issue Membrane Transport Modeling)
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Review

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Open AccessFeature PaperReview CO2 Permeability of Biological Membranes and Role of CO2 Channels
Received: 17 September 2017 / Revised: 13 October 2017 / Accepted: 18 October 2017 / Published: 24 October 2017
Cited by 4 | PDF Full-text (1825 KB) | HTML Full-text | XML Full-text
Abstract
We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO2 permeabilities in various tissues; (b) the physiological significance of the value of the CO2 permeability; (c) the mechanisms by which membrane CO2 permeability is modulated; [...] Read more.
We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO2 permeabilities in various tissues; (b) the physiological significance of the value of the CO2 permeability; (c) the mechanisms by which membrane CO2 permeability is modulated; (d) the role of the intracellular diffusivity of CO2 for the quantitative significance of cell membrane CO2 permeability; (e) the available evidence for the existence of CO2 channels in mammalian and artificial systems, with a brief view on CO2 channels in fishes and plants; and, (f) the possible significance of CO2 channels in mammalian systems. Full article
(This article belongs to the Special Issue Membrane Transport Modeling)
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