Journal Description
Membranes
Membranes
is an international, peer-reviewed, open access journal, published monthly online by MDPI, covers the broad aspects of the science and technology of both biological and non-biological membranes. European Membrane Society (EMS), Membrane Society of Australasia (MSA) and Polish Membrane Society (PTMem) are affiliated with Membranes and their members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, PubMed, PMC, CAPlus / SciFinder, Inspec, and other databases.
- Journal Rank: JCR - Q2 (Polymer Science) / CiteScore - Q2 (Chemical Engineering (miscellaneous))
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 13.6 days after submission; acceptance to publication is undertaken in 2.8 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
4.2 (2022);
5-Year Impact Factor:
4.3 (2022)
Latest Articles
Recent Advances in Dopamine-Based Membrane Surface Modification and Its Membrane Distillation Applications
Membranes 2024, 14(4), 81; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040081 (registering DOI) - 28 Mar 2024
Abstract
Surface modification of membranes is essential for improving flux and resistance to contamination for membranes. This is of great significance for membrane distillation, which relies on the vapor pressure difference across the membrane as the driving force. In recent years, biomimetic mussel-inspired substances
[...] Read more.
Surface modification of membranes is essential for improving flux and resistance to contamination for membranes. This is of great significance for membrane distillation, which relies on the vapor pressure difference across the membrane as the driving force. In recent years, biomimetic mussel-inspired substances have become the research hotspots. Among them, dopamine serves as surface modifiers that would achieve highly desirable and effective membrane applications owing to their unique physicochemical properties, such as universal adhesion, enhanced hydrophilicity, tunable reducibility, and excellent thermal conductivity. The incorporation of a hydrophilic layer, along with the utilization of photothermal properties and post-functionalization capabilities in modified membranes, effectively addresses challenges such as low flux, contamination susceptibility, and temperature polarization during membrane distillation. However, to the best of our knowledge, there is still a lack of comprehensive and in-depth discussions. Therefore, this paper systematically compiles the modification method of dopamine on the membrane surface and summarizes its application and mechanism in membrane distillation for the first time. It is believed that this paper would provide a reference for dopamine-assisted membrane separation during production, and further promote its practical application.
Full article
(This article belongs to the Special Issue Membrane Distillation for Water Treatment and Recycling)
►
Show Figures
Open AccessReview
Biogas Upgrading Using a Single-Membrane System: A Review
by
Wirginia Tomczak, Marek Gryta, Monika Daniluk and Sławomir Żak
Membranes 2024, 14(4), 80; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040080 - 27 Mar 2024
Abstract
In recent years, the use of biogas as a natural gas substitute has gained great attention. Typically, in addition to methane (CH4), biogas contains carbon dioxide (CO2), as well as small amounts of impurities, e.g., hydrogen sulfide (H2
[...] Read more.
In recent years, the use of biogas as a natural gas substitute has gained great attention. Typically, in addition to methane (CH4), biogas contains carbon dioxide (CO2), as well as small amounts of impurities, e.g., hydrogen sulfide (H2S), nitrogen (N2), oxygen (O2) and volatile organic compounds (VOCs). One of the latest trends in biogas purification is the application of membrane processes. However, literature reports are ambiguous regarding the specific requirement for biogas pretreatment prior to its upgrading using membranes. Therefore, the main aim of the present study was to comprehensively examine and discuss the most recent achievements in the use of single-membrane separation units for biogas upgrading. Performing a literature review allowed to indicate that, in recent years, considerable progress has been made on the use of polymeric membranes for this purpose. For instance, it has been documented that the application of thin-film composite (TFC) membranes with a swollen polyamide (PA) layer ensures the successful upgrading of raw biogas and eliminates the need for its pretreatment. The importance of the performed literature review is the inference drawn that biogas enrichment performed in a single step allows to obtain upgraded biogas that could be employed for household uses. Nevertheless, this solution may not be sufficient for obtaining high-purity gas at high recovery efficiency. Hence, in order to obtain biogas that could be used for applications designed for natural gas, a membrane cascade may be required. Moreover, it has been documented that a significant number of experimental studies have been focused on the upgrading of synthetic biogas; meanwhile, the data on the raw biogas are very limited. In addition, it has been noted that, although ceramic membranes demonstrate several advantages, experimental studies on their applications in single-membrane systems have been neglected. Summarizing the literature data, it can be concluded that, in order to thoroughly evaluate the presented issue, the long-term experimental studies on the upgrading of raw biogas with the use of polymeric and ceramic membranes in pilot-scale systems are required. The presented literature review has practical implications as it would be beneficial in supporting the development of membrane processes used for biogas upgrading.
Full article
(This article belongs to the Special Issue Advanced Gas Separation/Purification Membrane Processes)
Open AccessArticle
Electroformation of Giant Unilamellar Vesicles from Damp Lipid Films with a Focus on Vesicles with High Cholesterol Content
by
Ivan Mardešić, Zvonimir Boban and Marija Raguz
Membranes 2024, 14(4), 79; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040079 - 27 Mar 2024
Abstract
Giant unilamellar vesicles (GUVs) are membrane models used to study membrane properties. Electroformation is one of the methods used to produce GUVs. During electroformation protocol, dry lipid film is formed. The drying of the lipid film induces the cholesterol (Chol) demixing artifact, in
[...] Read more.
Giant unilamellar vesicles (GUVs) are membrane models used to study membrane properties. Electroformation is one of the methods used to produce GUVs. During electroformation protocol, dry lipid film is formed. The drying of the lipid film induces the cholesterol (Chol) demixing artifact, in which Chol forms anhydrous crystals which do not participate in the formation of vesicles. This leads to a lower Chol concentration in the vesicle bilayers compared to the Chol concentration in the initial lipid solution. To address this problem, we propose a novel electroformation protocol that includes rapid solvent exchange (RSE), plasma cleaning, and spin-coating methods to produce GUVs. We tested the protocol, focusing on vesicles with a high Chol content using different spin-coating durations and vesicle type deposition. Additionally, we compared the novel protocol using completely dry lipid film. The optimal spin-coating duration for vesicles created from the phosphatidylcholine/Chol mixture was 30 s. Multilamellar vesicles (MLVs), large unilamellar vesicles (LUVs) obtained by the extrusion of MLVs through 100 nm membrane pores and LUVs obtained by extrusion of previously obtained LUVs through 50 nm membrane pores, were deposited on an electrode for 1.5/1 Chol/phosphatidylcholine (POPC) lipid mixture, and the results were compared. Electroformation using all three deposited vesicle types resulted in a high GUV yield, but the deposition of LUVs obtained by the extrusion of MLVs through 100 nm membrane pores provided the most reproducible results. Using the deposition of these LUVs, we produced high yield GUVs for six different Chol concentrations (from 0% to 71.4%). Using a protocol that included dry lipid film GUVs resulted in lower yields and induced the Chol demixing artifact, proving that the lipid film should never be subjected to drying when the Chol content is high.
Full article
(This article belongs to the Special Issue Artificial Models of Biological Membranes—2nd Edition)
►▼
Show Figures
Figure 1
Open AccessArticle
Template-Free Synthesis of High Dehydration Performance CHA Zeolite Membranes with Increased Si/Al Ratio Using SSZ-13 Seeds
by
Jing Du, Jilei Jiang, Zhigang Xue, Yajing Hu, Bo Liu, Rongfei Zhou and Weihong Xing
Membranes 2024, 14(4), 78; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040078 - 27 Mar 2024
Abstract
Pervaporation is an energy-efficient alternative to conventional distillation for water/alcohol separations. In this work, a novel CHA zeolite membrane with an increased Si/Al ratio was synthesized in the absence of organic templates for the first time. Nanosized high-silica zeolite (SSZ-13) seeds were used
[...] Read more.
Pervaporation is an energy-efficient alternative to conventional distillation for water/alcohol separations. In this work, a novel CHA zeolite membrane with an increased Si/Al ratio was synthesized in the absence of organic templates for the first time. Nanosized high-silica zeolite (SSZ-13) seeds were used for the secondary growth of the membrane. The separation performance of membranes in different alcohol–aqueous mixtures was measured. The effects of water content in the feed and the temperature on the separation performance using pervaporation and vapor permeation were also studied. The best membrane showed a water/ethanol separation factor above 100,000 and a total flux of 1.2 kg/(m2 h) at 348 K in a 10 wt.% water–ethanol mixed solution. A membrane with high performance and an increased Si/Al ratio is promising for the application of alcohol dehydration.
Full article
(This article belongs to the Special Issue A Commemorative Special Issue in Honor of Dr. Moises Carreon)
Open AccessReview
The Conventional and Breakthrough Tool for the Study of L-Glutamate Transporters
by
Kanako Takahashi and Kaoru Sato
Membranes 2024, 14(4), 77; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040077 - 27 Mar 2024
Abstract
In our recent report, we clarified the direct interaction between the excitatory amino acid transporter (EAAT) 1/2 and polyunsaturated fatty acids (PUFAs) by applying electrophysiological and molecular biological techniques to Xenopus oocytes. Xenopus oocytes have a long history of use in the scientific
[...] Read more.
In our recent report, we clarified the direct interaction between the excitatory amino acid transporter (EAAT) 1/2 and polyunsaturated fatty acids (PUFAs) by applying electrophysiological and molecular biological techniques to Xenopus oocytes. Xenopus oocytes have a long history of use in the scientific field, but they are still attractive experimental systems for neuropharmacological studies. We will therefore summarize the pharmacological significance, advantages (especially in the study of EAAT2), and experimental techniques that can be applied to Xenopus oocytes; our new findings concerning L-glutamate (L-Glu) transporters and PUFAs; and the significant outcomes of our data. The data obtained from electrophysiological and molecular biological studies of Xenopus oocytes have provided us with further important questions, such as whether or not some PUFAs can modulate EAATs as allosteric modulators and to what extent docosahexaenoic acid (DHA) affects neurotransmission and thereby affects brain functions. Xenopus oocytes have great advantages in the studies about the interactions between molecules and functional proteins, especially in the case when the expression levels of the proteins are small in cell culture systems without transfections. These are also proper to study the mechanisms underlying the interactions. Based on the data collected in Xenopus oocyte experiments, we can proceed to the next step, i.e., the physiological roles of the compounds and their significances. In the case of EAAT2, the effects on the neurotransmission should be examined by electrophysiological approach using acute brain slices. For new drug development, pharmacokinetics pharmacodynamics (PKPD) data and blood brain barrier (BBB) penetration data are also necessary. In order not to miss the promising candidate compounds at the primary stages of drug development, we should reconsider using Xenopus oocytes in the early phase of drug development.
Full article
(This article belongs to the Special Issue The Xenopus Oocyte: A Tool for Membrane Biology, Second Edition)
Open AccessArticle
Mechanism of Silica Nanoparticle-Induced Particulate Fouling in Vacuum Membrane Distillation
by
Yejin Lee, Suyoung Jeong, Jae-Hyuk Kim and Sanghyun Jeong
Membranes 2024, 14(4), 76; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040076 - 27 Mar 2024
Abstract
Membrane distillation (MD) is a process driven by the vapor pressure difference dependent on temperature variation, utilizing a hydrophobic porous membrane. MD operates at low pressure and temperature, exhibiting resilience to osmotic pressure. However, a challenge arises as the membrane performance diminishes due
[...] Read more.
Membrane distillation (MD) is a process driven by the vapor pressure difference dependent on temperature variation, utilizing a hydrophobic porous membrane. MD operates at low pressure and temperature, exhibiting resilience to osmotic pressure. However, a challenge arises as the membrane performance diminishes due to temperature polarization (TP) occurring on the membrane surface. The vacuum MD process leverages the application of a vacuum to generate a higher vapor pressure difference, enhancing the flux and mitigating TP issues. Nevertheless, membrane fouling leads to decreased performance, causing membrane wetting and reducing the ion removal efficiency. This study investigates membrane fouling phenomena induced by various silica nanoparticle sizes (400, 900, and 1300 nm). The patterns of membrane fouling, as indicated by the flux reduction, vary depending on the particle size. Distinct MD performances are observed with changes in the feed water temperature and flow rate. When examining the membrane fouling mechanism for particles with a porosity resembling actual particulate materials, a fouling form similar to the solid type is noted. Therefore, this study elucidates the impact of particulate matter on membrane fouling under diverse conditions.
Full article
(This article belongs to the Section Membrane Applications)
►▼
Show Figures
Figure 1
Open AccessArticle
Simultaneous Recording of Remote Domain Dynamics in Membrane Proteins Using the Double-Labeled DXB/DXT Technique
by
Kazuhiro Mio, Tatsunari Ohkubo, Daisuke Sasaki, Mayui Sugiura, Kayoko Kawaguchi, Kazutaka Araki, Keizaburo Taninaka, Masaki Sakaguchi, Shunsuke Nozawa, Tatsuya Arai and Yuji C. Sasaki
Membranes 2024, 14(4), 75; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040075 - 27 Mar 2024
Abstract
►▼
Show Figures
Protein dynamics play important roles in biological functions, which accompany allosteric structure changes. Diffracted X-ray blinking (DXB) uses monochromatic X-rays and nanocrystal probes. The intramolecular motion of target proteins is analyzed from the intensity changes in detector signals at the diffraction rings. In
[...] Read more.
Protein dynamics play important roles in biological functions, which accompany allosteric structure changes. Diffracted X-ray blinking (DXB) uses monochromatic X-rays and nanocrystal probes. The intramolecular motion of target proteins is analyzed from the intensity changes in detector signals at the diffraction rings. In contrast, diffracted X-ray tracking (DXT) elucidates molecular dynamics by analyzing the trajectories of Laue spots. In this study, we have developed a dual-labeling technique for DXB and DXT, allowing the simultaneous observation of motions at different domains in proteins. We identified zinc oxide (ZnO) crystals as promising candidates for the second labeling probes due to their excellent diffraction patterns, high chemical stability, and favorable binding properties with proteins. The diffraction spots from the ZnO crystals are sufficiently separated from those of gold, enabling independent motion analysis at different domains. Dual-labeling DXB was employed for the motion analysis of the 5-HT2A receptor in living cells. Simultaneous motion recording of the N-terminus and the second extracellular loop demonstrated ligand-induced motion suppression at both domains. The dual-labeling DXT technique demonstrated a capsaicin-induced peak shift in the two-dimensional motion maps at the N-terminus of the TRPV1 protein, but the peak shift was not obvious in the C-terminus. The capsaicin-induced motion modulation was recovered by the addition of the competitive inhibitor AMG9810.
Full article
Figure 1
Open AccessArticle
Transfer of Sodium Ion across Interface between Na+-Selective Electrode Membrane and Aqueous Electrolyte Solution: Can We Use Nernst Equation If Current Flows through Electrode?
by
Valentina Keresten, Fedor Lazarev and Konstantin Mikhelson
Membranes 2024, 14(4), 74; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040074 - 27 Mar 2024
Abstract
Electrochemical impedance and chronopotentiometric measurements with Na+-selective solvent polymeric (PVC) membranes containing a neutral ionophore and a cation exchanger revealed low-frequency resistance, which is ascribed to Na+ ion transfer across the interface between the membrane and aqueous solution. The attribution
[...] Read more.
Electrochemical impedance and chronopotentiometric measurements with Na+-selective solvent polymeric (PVC) membranes containing a neutral ionophore and a cation exchanger revealed low-frequency resistance, which is ascribed to Na+ ion transfer across the interface between the membrane and aqueous solution. The attribution is based on the observed regular dependence of this resistance on the concentration of Na+ in solutions. The respective values of the exchange current densities were found to be significantly larger than the currents flowing through ion-selective electrodes (ISEs) during an analysis in non-zero-current mode. This fact suggests that the interfacial electrochemical equilibrium is not violated by the current flow and implies that the Nernst equation can be applied to interpret the data obtained in non-zero-current mode, e.g., constant potential coulometry.
Full article
(This article belongs to the Collection Feature Papers in Membrane Surface and Interfaces)
►▼
Show Figures
Figure 1
Open AccessArticle
Separation of Chloride and Sulfate Ions from Desulfurization Wastewater Using Monovalent Anions Selective Electrodialysis
by
Xufeng Tian, Dongbei Yue, Tao Hou, Fuyuan Xiao, Zhiping Wang and Weibin Cai
Membranes 2024, 14(4), 73; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040073 - 25 Mar 2024
Abstract
The high concentration of chloride ions in desulphurization wastewater is the primary limiting factor for its reusability. Monovalent anion selective electrodialysis (S-ED) enables the selective removal of chloride ions, thereby facilitating the reuse of desulfurization wastewater. In this study, different concentrations of NaCl
[...] Read more.
The high concentration of chloride ions in desulphurization wastewater is the primary limiting factor for its reusability. Monovalent anion selective electrodialysis (S-ED) enables the selective removal of chloride ions, thereby facilitating the reuse of desulfurization wastewater. In this study, different concentrations of NaCl and Na2SO4 were used to simulate different softened desulfurization wastewater. The effects of current density and NaCl and Na2SO4 concentration on ion flux, permselectivity ( ) and specific energy consumption were studied. The results show that Selemion ASA membrane exhibits excellent permselectivity for Cl− and SO42−, with a significantly lower flux observed for SO42− compared to Cl−. Current density exerts a significant influence on ion flux; as the current density increases, the flux of SO42− also increases but at a lower rate than that of Cl−, resulting in an increase in permselectivity. When the current density reaches 25 mA/cm2, the permselectivity reaches a maximum of 50.4. The increase in NaCl concentration leads to a decrease in the SO42− flux; however, the permselectivity is reduced due to the elevated Cl−/SO42− ratio. The SO42− flux increases with the increase in Na2SO4 concentration, while the permselectivity increases with the decrease in Cl−/SO42− ratio.
Full article
(This article belongs to the Section Membrane Applications)
►▼
Show Figures
Figure 1
Open AccessArticle
Experimental and Numerical Simulation Study of Oxygen Transport in Proton Exchange Membrane Fuel Cells at Intermediate Temperatures (80 °C–120 °C)
by
Jian Zhang, Yunfei Zhang, Zhengrui Xiao, Jinting Tan, Haining Zhang and Jun Yu
Membranes 2024, 14(4), 72; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14040072 - 22 Mar 2024
Abstract
Investigating the oxygen transport law within the Membrane Electrode Assembly at intermediate temperatures (80–120 °C) is crucial for enhancing fuel cell efficiency. This study analyzed the resistance to oxygen transport within the Membrane Electrode Assembly at intermediate temperatures using limiting current density and
[...] Read more.
Investigating the oxygen transport law within the Membrane Electrode Assembly at intermediate temperatures (80–120 °C) is crucial for enhancing fuel cell efficiency. This study analyzed the resistance to oxygen transport within the Membrane Electrode Assembly at intermediate temperatures using limiting current density and electrochemical impedance spectroscopy. The study findings reveal that, as temperature progressively increases, the Ostwald ripening effect leads to a 34% rise in the local oxygen transport resistance (Rlocal) in relation to the pressure-independent resistance (Rnp) within the cathode catalytic layer. Concurrently, the total transport resistance (Rtotal) decreases from 27.8% to 37.5% due to an increase in the gas diffusion coefficient and molecular reactivity; additionally, there is a decrease in the amount of liquid water inside the membrane electrode. A three-dimensional multiphysics field steady-state model was also established. The model demonstrates that the decrease in oxygen partial pressure can be mitigated effectively by increasing the back pressure at intermediate temperatures to ensure the cell’s performance.
Full article
(This article belongs to the Special Issue Advanced Water-Thermal Management and Gas Detection Technologies for Proton Exchange Membrane Fuel Cell)
►▼
Show Figures
Figure 1
Open AccessCommunication
Development of Structure–Property Relationships for Ammonium Transport through Charged Organogels
by
Adam L. Bachmann, Brock Hunter and Bryan S. Beckingham
Membranes 2024, 14(3), 71; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030071 - 21 Mar 2024
Abstract
Ammonia is a promising carbon-free fuel, but current methods to produce ammonia are energy intensive. New methods are thereby needed, with one promising method being electrochemical nitrogen reduction cells. Efficient cell operation requires robust catalysts but also efficient membrane separators that permit the
[...] Read more.
Ammonia is a promising carbon-free fuel, but current methods to produce ammonia are energy intensive. New methods are thereby needed, with one promising method being electrochemical nitrogen reduction cells. Efficient cell operation requires robust catalysts but also efficient membrane separators that permit the selective transport of ions while minimizing the transport of the products across the cell. Commercial membranes have an unknown morphology which makes designing improved cells challenging. To address this problem, we synthesized a series of membranes with controlled crosslinking density and chemical composition to understand their impact on ammonium transport. Higher crosslinking density led to lower ammonium permeability. At the highest crosslinking density, similar ammonium permeability was observed independent of the water volume fraction and hydrophobicity of the monomers. These results suggest new directions to develop membranes with reduced ammonium crossover to improve the efficiency of these electrochemical cells.
Full article
(This article belongs to the Section Polymeric Membranes)
►▼
Show Figures
Figure 1
Open AccessArticle
An Untargeted Metabolomics Strategy to Identify Substrates of Known and Orphan E. coli Transporters
by
Mohammad S. Radi, Lachlan J. Munro, Daniela Rago and Douglas B. Kell
Membranes 2024, 14(3), 70; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030070 - 20 Mar 2024
Abstract
Transport systems play a pivotal role in bacterial physiology and represent potential targets for medical and biotechnological applications. However, even in well-studied organisms like Escherichia coli, a notable proportion of transporters, exceeding as many as 30%, remain classified as orphans due to
[...] Read more.
Transport systems play a pivotal role in bacterial physiology and represent potential targets for medical and biotechnological applications. However, even in well-studied organisms like Escherichia coli, a notable proportion of transporters, exceeding as many as 30%, remain classified as orphans due to their lack of known substrates. This study leveraged high-resolution LC-MS-based untargeted metabolomics to identify candidate substrates for these orphan transporters. Human serum, including a diverse array of biologically relevant molecules, served as an unbiased source for substrate exposure. The analysis encompassed 26 paired transporter mutant contrasts (i.e., knockout vs. overexpression), compared with the wild type, revealing distinct patterns of substrate uptake and excretion across various mutants. The convergence of candidate substrates across mutant scenarios provided robust validation, shedding light on novel transporter-substrate relationships, including those involving yeaV, hsrA, ydjE, and yddA. Furthermore, several substrates were contingent upon the specific mutants employed. This investigation underscores the utility of untargeted metabolomics for substrate identification in the absence of prior knowledge and lays the groundwork for subsequent validation experiments, holding significant implications for both medical and biotechnological advancements.
Full article
(This article belongs to the Collection Feature Papers in Biological Membrane Functions)
►▼
Show Figures
Figure 1
Open AccessArticle
Coupling a Simple and Generic Membrane Fouling Model with Biological Dynamics: Application to the Modeling of an Anaerobic Membrane BioReactor (AnMBR)
by
Boumediene Benyahia, Amine Charfi, Geoffroy Lesage, Marc Heran, Brahim Cherki and Jérôme Harmand
Membranes 2024, 14(3), 69; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030069 - 20 Mar 2024
Abstract
A simple model is developed for membrane fouling, taking into account two main fouling phenomena: cake formation, due to attached solids on the membrane surface, and pore clogging, due to retained compounds inside the pores. The model is coupled with a simple anaerobic
[...] Read more.
A simple model is developed for membrane fouling, taking into account two main fouling phenomena: cake formation, due to attached solids on the membrane surface, and pore clogging, due to retained compounds inside the pores. The model is coupled with a simple anaerobic digestion model for describing the dynamics of an anaerobic membrane bioreactor (AnMBR). In simulations, we investigate its qualitative behavior: it is shown that the model exhibits satisfying properties in terms of a flux decrease due to membrane fouling. Comparing simulation and experimental data, the model is shown to predict quite well the dynamics of an AnMBR. The simulated flux best fits the experimental flux with a correlation coefficient for the calibration data set and for the validation data set. General discussions are given on possible control strategies to limit fouling and optimize the flux production. We show in simulations that these strategies allow one to increase the mean production flux to 33 L/(h·m2),whereas without control, it was 18 L/(h·m2).
Full article
(This article belongs to the Special Issue Advanced Membrane Bioreactors for Wastewater Treatment 2nd Edition)
►▼
Show Figures
Figure 1
Open AccessArticle
Has Extracorporeal Gas Exchange Performance Reached Its Peak?
by
Foivos Leonidas Mouzakis, Ali Kashefi, Flutura Hima, Khosrow Mottaghy and Jan Spillner
Membranes 2024, 14(3), 68; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030068 - 17 Mar 2024
Abstract
Extracorporeal gas exchange therapies evolved considerably within the first three–four decades of their appearance, and have since reached a mature stage, where minor alterations and discrete fine-tuning might offer some incremental improvement. A different approach is introduced here, making use of modern, purely
[...] Read more.
Extracorporeal gas exchange therapies evolved considerably within the first three–four decades of their appearance, and have since reached a mature stage, where minor alterations and discrete fine-tuning might offer some incremental improvement. A different approach is introduced here, making use of modern, purely diffusive membrane materials, and taking advantage of the elevated concentration gradient ensuing from gas pressure buildup in the gas chamber of the oxygenator. An assortment of silicone membrane gas exchangers were tested in vitro as per a modified protocol in pursuance of assessing their gas exchange efficiency under both regular and high-pressure aeration conditions. The findings point to a stark performance gain when pressurization of the gas compartment is involved; a 40% rise above atmospheric pressure elevates oxygen transfer rate (OTR) by nearly 30%. Carbon dioxide transfer rate (CTR) does not benefit as much from this principle, yet it retains a competitive edge when higher gas flow/blood flow ratios are employed. Moreover, implementation of purely diffusive membranes warrants a bubble-free circulation. Further optimization of the introduced method ought to pave the way for in vivo animal trials, which in turn may potentially unveil new realms of gas exchange performance for therapies associated with extracorporeal circulation.
Full article
(This article belongs to the Topic Extracorporeal Membrane Oxygenation (ECMO))
►▼
Show Figures
Figure 1
Open AccessArticle
Numerical Simulation of Mass Transfer in Hollow Fiber Membrane Module for Membrane-Based Artificial Organs
by
Ziheng Wang, Shaofeng Xu, Yifan Yu, Wei Zhang and Xuechang Zhang
Membranes 2024, 14(3), 67; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030067 - 10 Mar 2024
Abstract
►▼
Show Figures
The mass transfer behavior in a hollow fiber membrane module of membrane-based artificial organs (such as artificial liver or artificial kidney) were studied by numerical simulation. A new computational fluid dynamics (CFD) method coupled with K-K equation and the tortuous capillary pore diffusion
[...] Read more.
The mass transfer behavior in a hollow fiber membrane module of membrane-based artificial organs (such as artificial liver or artificial kidney) were studied by numerical simulation. A new computational fluid dynamics (CFD) method coupled with K-K equation and the tortuous capillary pore diffusion model (TCPDM) was proposed for the simulations. The urea clearance rate predicted by the use of the numerical model agrees well with the experimental data, which verifies the validity of our numerical model. The distributions of concentration, pressure, and velocity in the hollow fiber membrane module were obtained to analyze the mass transfer behaviors of bilirubin and bovine serum albumin (BSA), and the effects of tube-side flow rate, shell-side flow rate, and fiber tube length on the bilirubin or BSA clearance rate were studied. The results show that the solute transport mainly occurred in the near inlet regions in the hollow fiber membrane module. Increasing the tube-side flow rate and the fiber tube length can effectively enhance the solute clearance rate, while the shell-side flow rate has less influence on the BSA clearance. The clearance of macromolecule BSA is dominated by convective solute transport, while the clearance of small molecule bilirubin is significantly affected by both convective and diffusive solute transport.
Full article
Figure 1
Open AccessArticle
Permeance of Condensable Gases in Rubbery Polymer Membranes at High Pressure
by
Karina Schuldt, Jelena Lillepärg, Jan Pohlmann, Torsten Brinkmann and Sergey Shishatskiy
Membranes 2024, 14(3), 66; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030066 - 06 Mar 2024
Abstract
The gas transport properties of thin film composite membranes (TFCMs) with selective layers of PolyActive™, polydimethylsiloxane (PDMS), and polyoctylmethylsiloxane (POMS) were investigated over a range of temperatures (10–34 °C; temperature increments of 2 °C) and pressures (1–65 bar abs; 38 pressure increments). The
[...] Read more.
The gas transport properties of thin film composite membranes (TFCMs) with selective layers of PolyActive™, polydimethylsiloxane (PDMS), and polyoctylmethylsiloxane (POMS) were investigated over a range of temperatures (10–34 °C; temperature increments of 2 °C) and pressures (1–65 bar abs; 38 pressure increments). The variation in the feed pressure of condensable gases CO2 and C2H6 enabled the observation of peaks of permeance in dependence on the feed pressure and temperature. For PDMS and POMS, the permeance peak was reproduced at the same feed gas activity as when the feed temperature was changed. PolyActive™ TFCM showed a more complex behaviour, most probably due to a higher CO2 affinity towards the poly(ethylene glycol) domains of this block copolymer. A significant decrease in the permeate temperature associated with the Joule–Thomson effect was observed for all TFCMs. The stepwise permeance drop was observed at a feed gas activity of p/po ≥ 1, clearly indicating that a penetrant transfer through the selective layer occurs only according to the conditions on the feed side of the membrane. The permeate side gas temperature has no influence on the state of the selective layer or penetrant diffusing through it. The most likely cause of the observed TFCM behaviour is capillary condensation of the penetrant in the swollen selective layer material, which can be provoked by the clustering of penetrant molecules.
Full article
(This article belongs to the Special Issue Advanced Membrane Materials for CO2 Capture and Separation)
►▼
Show Figures
Figure 1
Open AccessArticle
Joint Modeling and Operational Optimization of a Reverse Osmosis–Mechanical Vapor Recompression System for Coal-Fired Power Plant Wastewater
by
Fengling Xie, Yan Zhao, Aipeng Jiang, Rui Zhao, Chuang Li and Jian Wang
Membranes 2024, 14(3), 65; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030065 - 04 Mar 2024
Abstract
The operation of coal-fired power plants generates a large amount of wastewater. With the issuance of increasingly strict drainage standards, the cost of wastewater treatment is increasing, and the need to reduce the cost of wastewater treatment is becoming increasingly urgent. Thus, based
[...] Read more.
The operation of coal-fired power plants generates a large amount of wastewater. With the issuance of increasingly strict drainage standards, the cost of wastewater treatment is increasing, and the need to reduce the cost of wastewater treatment is becoming increasingly urgent. Thus, based on the principles of reverse osmosis (RO) and mechanical vapor recompression (MVR) in wastewater treatment, the operational optimization of an RO-MVR joint system was studied in this work with the consideration of reducing the operating costs of wastewater treatment under given operational conditions. Firstly, based on the basic principles of RO and MVR, corresponding mechanism models were established and their accuracy was verified. Then, an economic model of the RO-MVR joint system was established, with the goal of minimizing the water production unit price and daily operating costs of the joint system for optimization analysis. Finally, we analyzed the cost and water production performance of the RO-MVR joint system before and after optimization under different operating conditions. The results show that this optimization based on the RO-MVR joint system will reduce the unit price of water production to 3.16 CNY/m3, with the daily operating costs being decreased by 22% compared to before optimization. This result helps to reduce the cost of zero-discharge wastewater treatment in coal-fired power plants.
Full article
(This article belongs to the Special Issue Recent Advances in Desalination Based on Membrane Technology)
►▼
Show Figures
Figure 1
Open AccessCommunication
Membranes and Synaptosomes Used to Investigate Synaptic GABAergic Currents in Epileptic Patients
by
Alessandro Gaeta, Lilian Juliana Lissner, Veronica Alfano, Pierangelo Cifelli, Alessandra Morano, Cristina Roseti, Angela Di Iacovo, Eleonora Aronica, Eleonora Palma and Gabriele Ruffolo
Membranes 2024, 14(3), 64; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030064 - 02 Mar 2024
Abstract
Among the most prevalent neurological disorders, epilepsy affects about 1% of the population worldwide. We previously found, using human epileptic tissues, that GABAergic neurotransmission impairment is a key mechanism that drives the pathological phenomena that ultimately lead to generation and recurrence of seizures.
[...] Read more.
Among the most prevalent neurological disorders, epilepsy affects about 1% of the population worldwide. We previously found, using human epileptic tissues, that GABAergic neurotransmission impairment is a key mechanism that drives the pathological phenomena that ultimately lead to generation and recurrence of seizures. Using both a “microtransplantation technique” and synaptosomes preparations from drug-resistant temporal lobe epilepsies (TLEs), we used the technique of two-electrode voltage clamp to record GABA-evoked currents, focusing selectively on the synaptic “fast inhibition” mediated by low-affinity GABAA receptors. Here, we report that the use-dependent GABA current desensitization (i.e., GABA rundown, which is evoked by applying to the cells consecutive pulses of GABA, at high concentration), which is a distinguishing mark of TLE, is mainly dependent on a dysfunction that affects synaptic GABAA receptors. In addition, using the same approaches, we recorded a depolarized GABA reversal potential in synaptosomes samples from the human epileptic subicula of TLE patients. These results, which confirm previous experiments using total membranes, suggest an altered chloride homeostasis in the synaptic area. Finally, the lack of a Zn2+ block of GABA-evoked currents using the synaptosomes supports the enrichment of “synaptic fast inhibitory” GABAA receptors in this preparation. Altogether, our findings suggest a pathophysiological role of low-affinity GABAA receptors at the synapse, especially during the fast and repetitive GABA release underlying recurrent seizures.
Full article
(This article belongs to the Special Issue The Xenopus Oocyte: A Tool for Membrane Biology, Second Edition)
►▼
Show Figures
Figure 1
Open AccessCommunication
Preparation and Gas Separation of Amorphous Silicon Oxycarbide Membrane Supported on Silicon Nitride Membrane
by
Hengguo Jin and Xin Xu
Membranes 2024, 14(3), 63; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030063 - 02 Mar 2024
Abstract
►▼
Show Figures
An amorphous silicon oxycarbide membrane supported on a silicon nitride membrane substrate was prepared. A starting suspension containing polyhydromethylsiloxane (PHMS), tetramethyltetravinyl-cyclotetrasiloxane (TMTVS) and a platinum catalyst was first prepared and spin-coated on a silicon nitride membrane, and then the suspension was cross-linked and
[...] Read more.
An amorphous silicon oxycarbide membrane supported on a silicon nitride membrane substrate was prepared. A starting suspension containing polyhydromethylsiloxane (PHMS), tetramethyltetravinyl-cyclotetrasiloxane (TMTVS) and a platinum catalyst was first prepared and spin-coated on a silicon nitride membrane, and then the suspension was cross-linked and cured, followed by pyrolyzing at 1000 °C under a flowing Ar atmosphere. A dense amorphous silicon oxycarbon ceramic membrane with a thickness of about 1.8 µm was strongly bonded to the Si3N4 membrane substrate. The single gas permeation of H2 and CO2 indicated that the ideal permeation selectivity of H2/CO2 was up to 20 at 25 °C and 0.5 MPa with good long-term stability, indicating the potential application of the obtained membrane for hydrogen purification.
Full article
Figure 1
Open AccessArticle
The Interaction between Anesthetic Isoflurane and Model-Biomembrane Monolayer Using Simultaneous Quartz Crystal Microbalance (QCM) and Quartz Crystal Impedance (QCI) Methods
by
Yasushi Yamamoto, Daiki Ito, Honoka Akatsuka, Hiroki Noguchi, Arisa Matsushita, Hyuga Kinekawa, Hirotaka Nagano, Akihiro Yoshino, Keijiro Taga, Zameer Shervani and Masato Yamamoto
Membranes 2024, 14(3), 62; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes14030062 - 27 Feb 2024
Abstract
The interaction between anesthetic Isoflurane (Iso) and model-biomembrane on the water surface has been investigated using quartz crystal microbalance (QCM) and quartz crystal impedance (QCI) methods. The model-biomembranes used were dipalmitoyl phosphatidyl choline (DPPC), DPPC-palmitic acid (PA) mixture (DPPC:PA = 8:2), DPPC-Alamethicin (Al)
[...] Read more.
The interaction between anesthetic Isoflurane (Iso) and model-biomembrane on the water surface has been investigated using quartz crystal microbalance (QCM) and quartz crystal impedance (QCI) methods. The model-biomembranes used were dipalmitoyl phosphatidyl choline (DPPC), DPPC-palmitic acid (PA) mixture (DPPC:PA = 8:2), DPPC-Alamethicin (Al) mixture (DPPC:Al = 39:1), and DPPC-β-Lactoglobulin (βLG) mixture (DPPC:βLG = 139:1) monolayers, respectively. The quartz crystal oscillator (QCO) was attached horizontally to each monolayer, and QCM and QCI measurements were performed simultaneously. It was found that Iso hydrate physisorbed on each monolayer/water interface from QCM and changed those interfacial viscosities from QCI. With an increase in Iso concentration, pure DPPC, DPPC-PA mixed, and DPPC-Al mixed monolayers showed a two-step process of Iso hydrate on both physisorption and viscosity, whereas it was a one-step for the DPPC-βLG mixed monolayer. The viscosity change in the DPPC-βLG mixed monolayer with the physisorption of Iso hydrate was much larger than that of other monolayers, in spite of the one-step process. From these results, the action mechanism of anesthetics and their relevance to the expression of anesthesia were discussed, based on the “release of interfacial hydrated water” hypothesis on the membrane/water interface.
Full article
(This article belongs to the Special Issue Morphological and Highly Sensitive Detection (HSD) Observations of Monolayers)
►▼
Show Figures
Figure 1
Journal Menu
► ▼ Journal Menu-
- Membranes Home
- Aims & Scope
- Editorial Board
- Reviewer Board
- Topical Advisory Panel
- Instructions for Authors
- Special Issues
- Topics
- Sections & Collections
- Article Processing Charge
- Indexing & Archiving
- Editor’s Choice Articles
- Most Cited & Viewed
- Journal Statistics
- Journal History
- Journal Awards
- Society Collaborations
- Conferences
- Editorial Office
Journal Browser
► ▼ Journal BrowserHighly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
Materials, Membranes, Molecules, Processes, Water
Technologies for Wastewater and Sludge Treatment
Topic Editors: Bin Dong, Sisi Chen, Nan LvDeadline: 31 March 2024
Topic in
Energies, Membranes, Minerals, Toxics, Water
Renewable Energies for Water Treatment and Reuse in Mining Industries
Topic Editors: Sergio Santoro, Francesco Chidichimo, Barbara Ruffino, Lourdes García-RodríguezDeadline: 30 June 2024
Topic in
Biomedicines, JCM, Membranes, Metabolites, Reports
Nephrology and Dialysis: From Bench to Bedside
Topic Editors: Eiichi Sato, Tsukasa NakamuraDeadline: 31 July 2024
Topic in
Energies, IJMS, Membranes, Separations, Water
Membrane Separation Technology Research
Topic Editors: Chenxiao Jiang, Zhe Yang, Ying MeiDeadline: 15 September 2024
Conferences
Special Issues
Special Issue in
Membranes
Membrane Structure and Function: From Model to Native, and from Experiment to Theory
Guest Editors: Cristiano Giordani, Brian RodriguezDeadline: 30 March 2024
Special Issue in
Membranes
Membrane-Based Technologies for Water/Wastewater Treatment
Guest Editors: Emmanuel Kweinor Tetteh, Martha Noro Chollom, Sudesh Rathilal, Babatunde Femi BakareDeadline: 31 March 2024
Special Issue in
Membranes
Latest Research on Pollutants Removal from Aqueous Media by Membrane Processes
Guest Editor: Gerardo LeónDeadline: 20 April 2024
Special Issue in
Membranes
Electrochemical Membranes: Materials, Characterization, Testing, and Cleaning
Guest Editors: Svetlozar Velizarov, Ivan Merino-GarciaDeadline: 30 April 2024
Topical Collections
Topical Collection in
Membranes
Applied, Engineering and Environmental Microbiology and Biofilms
Collection Editors: Gamini Seneviratne, Yanrui Ye, Zhenbo Xu, Guanglei Qiu, Jing Lin, Jian Sun
Topical Collection in
Membranes
Featured Reviews in Membrane Science
Collection Editors: Spas D. Kolev, Tae-Hyun Bae, Laurent Bazinet, Claus Hélix-Nielsen
Topical Collection in
Membranes
Feature Papers in Membrane Bio-Reactor Valorisation
Collection Editors: Gaetano Di Bella, Santo Fabio Corsino
Topical Collection in
Membranes
Feature Papers in Biological Membrane Composition and Structures
Collection Editor: Shiro Suetsugu