You seem to have javascript disabled. Please note that many of the page functionalities won't work as expected without javascript enabled.

Search for Articles:

Title / Keyword

Author / Affiliation / Email

Journal

Article Type

Advanced Search

Section

Special Issue

Volume

Issue

Number

Page

Logical OperatorOperator

Search Text

Search Type

Pharmaceutical Removal with Photocatalytically Active Nanocomposite Membranes
Combined Effects of Surface Roughness, Solubility Parameters, and Hydrophilicity on Biofouling of Reverse Osmosis Membranes
The Efficiency of Polyester-Polysulfone Membranes, Coated with Crosslinked PVA Layers, in the Water Desalination by Pervaporation

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 (Chemistry, Physical) / CiteScore - Q2 (Chemical Engineering (miscellaneous))
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.6 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the first half of 2024).
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: 3.3 (2023); 5-Year Impact Factor: 3.6 (2023)

Imprint Information Journal Flyer Open Access ISSN: 2077-0375

Latest Articles

18 pages, 5254 KiB

Open AccessArticle

Polysulfone-Based Membranes Modified with Ionic Liquids and Silica for Potential Fuel Cell Applications

by Emma Fernández-Llamazares, Thi Hai Van Nguyen, Pere Verdugo, Aitor Gual, Diogo M. E. Garcia, Claudia Delgado Simão, Miriam Díaz de los Bernardos and Adrianna Nogalska

Membranes 2024, 14(12), 270; https://doi.org/10.3390/membranes14120270 - 13 Dec 2024

The urgent need for sustainable, low-emission energy solutions has positioned proton exchange membrane fuel cells (PEMFCs) as a promising technology in clean energy conversion. Polysulfone (PSF) membranes with incorporated ionic liquid (IL) and hydrophobic polydimethylsiloxane-functionalized silica (SiO₂-PDMS) were developed and characterized [...] Read more.

The urgent need for sustainable, low-emission energy solutions has positioned proton exchange membrane fuel cells (PEMFCs) as a promising technology in clean energy conversion. Polysulfone (PSF) membranes with incorporated ionic liquid (IL) and hydrophobic polydimethylsiloxane-functionalized silica (SiO₂-PDMS) were developed and characterized for their potential application in PEMFCs. Using a phase inversion method, membranes with various combinations of PSFs, SiO₂-PDMS, and 1-butyl-3-methylimidazolium triflate (BMI.TfO) (1–10 wt%) were prepared and characterized to assess their morphology, porosity, wettability, ionic conductivity, and thermal stability. Incorporating IL significantly altered the membrane structure, increasing porosity and surface roughness, while SiO₂-PDMS enhanced IL retention, reducing leakage by up to 32%. Proton conductivity increased by up to 30 times compared to pure PSF, and membranes exhibited high hydrophilicity at optimal IL concentrations. This work highlights the potential of IL and silica-based membranes for practical applications in PEMFCs. Full article

(This article belongs to the Section Membrane Applications for Energy)

► Show Figures

Figure 1

14 pages, 3524 KiB

Open AccessArticle

Enhanced Performance and Durability of Pore-Filling Membranes for Anion Exchange Membrane Water Electrolysis

by Minyoung Lee and Jin-Soo Park

Membranes 2024, 14(12), 269; https://doi.org/10.3390/membranes14120269 - 12 Dec 2024

Four distinct pore-filling anion exchange membranes (PFAEMs) were prepared, and their mechanical properties, ion conductivity, and performance in anion exchange membrane water electrolysis (AEMWE) were evaluated. The fabricated PFAEMs demonstrated exceptional tensile strength, which was approximately 14 times higher than that of the [...] Read more.

Four distinct pore-filling anion exchange membranes (PFAEMs) were prepared, and their mechanical properties, ion conductivity, and performance in anion exchange membrane water electrolysis (AEMWE) were evaluated. The fabricated PFAEMs demonstrated exceptional tensile strength, which was approximately 14 times higher than that of the commercial membrane, despite being nearly half as thin. Ion conductivity measurements revealed that acrylamide-based membranes outperformed benzyl-based ones, exhibiting 25% and 41% higher conductivity when using crosslinkers with two and three crosslinking sites, respectively. The AEMWE performance directly correlated with the hydrophilicity and ion exchange capacity (IEC) of the membranes. Specifically, AE_3C achieved the highest performance, supported by its superior IEC and ionic conductivity. Durability tests showed that AE_3C outlasted the commercial membrane, with a delayed voltage increase corresponding to its higher IEC, confirming the importance of increased ion-exchange functional groups in ensuring longevity. These results highlight the critical role of hydrophilic monomers and crosslinker structure in optimizing PFAEMs for enhanced performance and durability in AEMWE applications. Full article

(This article belongs to the Section Membrane Applications for Energy)

► Show Figures

Figure 1

19 pages, 2651 KiB

Open AccessArticle

Cationic/Anionic Poly(p-Phenylene Oxide) Membranes: Preparation and Electrodialysis Performance for Nickel Recovery from Industrial Effluents

by Fabrício Wilbert, Joana Farias Corte, Felipe Tiago do Nascimento, Vanusca Dalosto Jahno, Marco Antônio Siqueira Rodrigues, Fabrício Celso, Salatiel W. da Silva and Andrea Moura Bernardes

Membranes 2024, 14(12), 268; https://doi.org/10.3390/membranes14120268 - 11 Dec 2024

Electrodialysis (ED) has already been applied to recover nickel in galvanizing processes, allowing nickel recovery and the production of a treated effluent with demineralized water quality. However, the growth in ED use is still limited by the production and commercialization of ion-selective membranes, [...] Read more.

Electrodialysis (ED) has already been applied to recover nickel in galvanizing processes, allowing nickel recovery and the production of a treated effluent with demineralized water quality. However, the growth in ED use is still limited by the production and commercialization of ion-selective membranes, currently limited to a few large companies. Therefore, this paper presents the development of homogeneous cationic and anionic membranes made from poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) for ED use. Cationic membranes were prepared by the sulfonation reaction of PPO under different experimental conditions (PPO:H₂SO₄ molar ratio and reaction time). Anionic membranes were prepared by the bromination reaction of PPO, followed by the amination reaction. The membranes were characterized for their chemical and electrochemical properties, including ion exchange capacity, conductivity, thermal stability, and surface morphology. The optimal conditions for cationic membrane sulfonation were achieved with a 1:4.4 PPO:H₂SO₄ molar ratio, and a reaction time of 0.5 h. For anionic membranes, the best results were obtained with bromination, with a PPO:NBS (N-Bromosuccinimide) molar ratio of 1:0.5, followed by 14 days of amination. Overall, 91.8% chloride, 90.9% sulfate, and 85.5% nickel ion extraction was achieved, highlighting PPO as a promising polymer for the development of anionic and cationic ion-selective membranes for ED. Full article

(This article belongs to the Special Issue Research on Electrodialytic Processes)

► Show Figures

Figure 1

25 pages, 5618 KiB

Open AccessArticle

Effects of Nicotine on the Thermodynamics and Phase Coexistence of Pulmonary Surfactant Model Membranes

by Fadi S. S. Magalhães, Ernanni D. Vieira, Mariana R. B. Batista, Antonio J. Costa-Filho and Luis G. M. Basso

Membranes 2024, 14(12), 267; https://doi.org/10.3390/membranes14120267 - 11 Dec 2024

Phase separation is essential for membrane function, and alterations in phase coexistence by membrane-interacting molecules, such as nicotine, can impair membrane stability. With the increasing use of e-cigarettes, concerns have arisen about the impact of nicotine on pulmonary surfactants. Here, we used differential [...] Read more.

Phase separation is essential for membrane function, and alterations in phase coexistence by membrane-interacting molecules, such as nicotine, can impair membrane stability. With the increasing use of e-cigarettes, concerns have arisen about the impact of nicotine on pulmonary surfactants. Here, we used differential scanning calorimetry (DSC), molecular dynamics (MD) simulations, and electron spin resonance (ESR) to examine nicotine’s effect on the phase coexistence of two surfactant models: pure DPPC and a DPPC/POPC/POPG mixture. Our DSC analysis revealed that nicotine interacts with both membranes, increasing enthalpy and entropy change during the phase transition. ESR revealed that nicotine affects membrane fluidity and packing of DPPC more effectively than the ternary mixture, especially near the surface. MD simulations showed that neutral nicotine resides in the mid-plane, while protonated nicotine remains near the surface. Nicotine binding to the membranes is dynamic, switching between bound and unbound states. Analysis via ESR/van’t Hoff method revealed changes in the thermodynamics of phase coexistence, yielding distinct non-linear behavior. Nicotine altered the temperature dependence of the free energy, modifying the thermodynamic driving forces and the balance of non-covalent lipid interactions. These findings provide new insights into how nicotine influences pulmonary surfactant model membranes, with potential implications for surfactant function. Full article

(This article belongs to the Section Biological Membranes)

► Show Figures

Figure 1

12 pages, 6098 KiB

Open AccessArticle

A Case Study on Recycling Industrial Wastewater with Nanofiltration Membrane Separation Technology

by Yiqiang Deng, Xiaoqian Bai, Jialong Lin, Linyan Yang, Yuqing Lin, Mingyue Lin and Guangli Xiu

Membranes 2024, 14(12), 266; https://doi.org/10.3390/membranes14120266 - 9 Dec 2024

As pressure on water resources intensifies and stringent regulations for groundwater and surface water are enacted, wastewater recycling has emerged as a key research objective for many enterprises. In this study, based on the actual wastewater discharged from Eternal Electronic (Suzhou, China) Co., [...] Read more.

As pressure on water resources intensifies and stringent regulations for groundwater and surface water are enacted, wastewater recycling has emerged as a key research objective for many enterprises. In this study, based on the actual wastewater discharged from Eternal Electronic (Suzhou, China) Co., Ltd., the performance differences in different membrane materials in treating this wastewater were analyzed and compared. The NF90 membrane was ultimately selected as the most suitable choice for treating this wastewater with optimal operating conditions of 150 psi, 25 °C, and 1 L/min, respectively. All the indices of wastewater treatment can satisfy the standard of circulating cooling water. In addition, this work is closely combined with the practical applications by using an HCl solution (pH = 3–4) to clean the fouled membranes, thus effectively solving the membrane fouling in the treatment process. This approach not only satisfies the environmental management requirements of enterprises but also provides valuable insights for similar wastewater treatment projects. Full article

(This article belongs to the Section Membrane Applications for Water Treatment)

► Show Figures

Figure 1

14 pages, 7902 KiB

Open AccessArticle

Effect of Anion-Conducting Electrolytes in Pore-Filling Membranes on Performance and Durability in Water Electrolysis

by Dahye Jeong and Jin-Soo Park

Membranes 2024, 14(12), 265; https://doi.org/10.3390/membranes14120265 - 9 Dec 2024

This study examines the effect of the structural characteristics of anion-conducting monomers within pore-filling anion exchange membranes on the performance and durability of anion exchange membrane water electrolysis. Analysis reveals that acrylamide- and acrylate-based membranes show optimal performance without methyl groups, with acrylamide-based [...] Read more.

This study examines the effect of the structural characteristics of anion-conducting monomers within pore-filling anion exchange membranes on the performance and durability of anion exchange membrane water electrolysis. Analysis reveals that acrylamide- and acrylate-based membranes show optimal performance without methyl groups, with acrylamide-based membranes outperforming their acrylate counterparts in current density, particularly at 1.8 V. The AC-AA and AC-MAA monomers demonstrate durability, with AC-MAA showing enhanced alkaline stability, likely due to the presence of a methyl group, resulting in an increase rate of 746.6 μV/h compared to AC-AA’s 1150 μV/h. This study also shows that a commercial membrane exhibits a decrease rate of 3116 μV/h, underscoring the pore-filling membrane’s superior durability. Furthermore, the findings highlight that pore-filling membrane technology enables better durability and performance in electrolysis environments compared to the commercial homogeneous membrane, particularly when alkaline conditions are present. This research provides a foundation for designing high-performance, durable membranes for efficient hydrogen production, particularly under water electrolysis conditions. Full article

(This article belongs to the Section Membrane Applications for Energy)

► Show Figures

Figure 1

22 pages, 1351 KiB

Open AccessReview

Advanced Low–Cost Natural Materials for High–Performance Oil–Water Filtration Membranes: Achievements, Challenges, and Future Directions

by Nthabiseng Ramanamane, Mothibeli Pita and Baonhe Sob

Membranes 2024, 14(12), 264; https://doi.org/10.3390/membranes14120264 - 8 Dec 2024

The development of affordable ceramic membranes is essential for reducing expenses and optimizing the treatment of oily wastewater. There is an urgent demand for membranes that are not only affordable and easy to operate but also stable and capable of managing high fluxes [...] Read more.

The development of affordable ceramic membranes is essential for reducing expenses and optimizing the treatment of oily wastewater. There is an urgent demand for membranes that are not only affordable and easy to operate but also stable and capable of managing high fluxes to address the increasing volumes of oily wastewater. The significant production demands associated with many commercially available ceramic membranes, primarily due to the use of specialised raw materials and intricate processing methods, limiting their suitability for many wastewater treatment applications. Consequently, there is a rising interest in creating innovative ceramic membranes using affordable materials and simpler production techniques. This study reviewed the oil–water ceramic membranes utilizing affordable natural ceramic materials aimed at improving membrane performance. It focused on reviewing the environmentally friendly and economically viable membranes derived from natural ceramic resources as an alternative to conventional synthetic membranes. These natural ceramic materials possess crucial properties like hydrophilicity and oleophobicity, which are vital for effective oil–water separation. The ceramic membranes were reviewed for their filtration performance and advantages. It was reported that these natural ceramic material-based membranes demonstrate superior separation efficiency, and strong mechanical stability, making them promising candidates for sustainable water treatment. Full article

(This article belongs to the Section Membrane Applications for Water Treatment)

► Show Figures

Figure 1

12 pages, 9226 KiB

Open AccessArticle

High-Performance Fluorine-Lean Thin Aromatic Hydrocarbon Membranes Based on Polyvinylidene Fluoride for Hydrogen Fuel Cells

by Tamas Nemeth, Zongyi Han and Lorenz Gubler

Membranes 2024, 14(12), 263; https://doi.org/10.3390/membranes14120263 - 7 Dec 2024

The impeding ban on per- and polyfluoroalkyl substances (PFAS) prompted researchers to focus on hydrocarbon-based materials as constituents of next-generation proton exchange membranes (PEMs) for polymer electrolyte fuel cells (PEFCs). Here, we report on the fuel cell performance and durability of fluorine-lean PEMs [...] Read more.

The impeding ban on per- and polyfluoroalkyl substances (PFAS) prompted researchers to focus on hydrocarbon-based materials as constituents of next-generation proton exchange membranes (PEMs) for polymer electrolyte fuel cells (PEFCs). Here, we report on the fuel cell performance and durability of fluorine-lean PEMs prepared by the post-sulfonation of co-grafted α-methylstyrene (AMS) and 2-methylene glutaronitrile (MGN) monomers into preirradiated 12 µm polyvinylidene fluoride (PVDF) base film. The membranes were subjected to two distinctly different accelerated stress test (AST) protocols performed at open-circuit voltage (OCV): the US Department of Energy-similar chemical AST (90 °C, 30% relative humidity (RH), H₂/air, 1 bar_a), developed originally for perfluoroalkylsulfonic acid (PFSA) membranes, and the high relative humidity AST (80 °C, 100% RH, H₂/O₂, 2.5 bar_a), designed for aromatic hydrocarbon membranes. We found that doping the grafted membranes with a metalated porphyrin antioxidant can simultaneously reduce membrane aging and improve fuel cell performance. Full article

(This article belongs to the Special Issue Recent Advances in Fluorine-Free Membranes)

► Show Figures

Figure 1

13 pages, 3506 KiB

Open AccessArticle

Study on Efficient Operating Conditions for Bipolar Membrane Electrodialysis Using Different Ion Species and Anion-Exchange Membranes

by Sadato Kikuchi, Souichiro Hirao, Shunya Kayakiri, Yuriko Kakihana and Mitsuru Higa

Membranes 2024, 14(12), 262; https://doi.org/10.3390/membranes14120262 - 6 Dec 2024

To investigate efficient operating conditions for bipolar membrane electrodialysis (BMED), a comparison of current efficiency (CE) and power intensity (PI) was conducted using different anion-exchange membranes (AEMs) and salt solutions (NaCl and Na₂SO₄) as feed [...] Read more.

To investigate efficient operating conditions for bipolar membrane electrodialysis (BMED), a comparison of current efficiency (CE) and power intensity (PI) was conducted using different anion-exchange membranes (AEMs) and salt solutions (NaCl and Na₂SO₄) as feed solutions in BMED. The results indicated that CE was higher and PI was lower for a commercial proton-blocking AEM (ACM) than for a standard AEM (ASE) when NaCl was used. This is because ASE has a higher water content than ACM, leading to greater H⁺ permeability, which reduces CE. Conversely, when Na₂SO₄ was used, ASE exhibited higher CE and lower cell voltage (CV) than ACM, resulting in lower PI for ASE. This is attributable to the fact that, with Na₂SO₄, the effect of CV was more significant than H⁺ permeability. These findings suggest that efficient operation can be achieved by selecting the appropriate combination of AEMs and salt solutions. Full article

(This article belongs to the Special Issue Design, Synthesis and Applications of Ion Exchange Membranes)

► Show Figures

Figure 1

16 pages, 1241 KiB

Open AccessArticle

“Head-to-Toe” Lipid Properties Govern the Binding and Cargo Transfer of High-Density Lipoprotein

by Florian Weber, Markus Axmann, Erdinc Sezgin, Mariana Amaro, Taras Sych, Armin Hochreiner, Martin Hof, Gerhard J. Schütz, Herbert Stangl and Birgit Plochberger

Membranes 2024, 14(12), 261; https://doi.org/10.3390/membranes14120261 - 6 Dec 2024

The viscoelastic properties of biological membranes are crucial in controlling cellular functions and are determined primarily by the lipids’ composition and structure. This work studies these properties by varying the structure of the constituting lipids in order to influence their interaction with high-density [...] Read more.

The viscoelastic properties of biological membranes are crucial in controlling cellular functions and are determined primarily by the lipids’ composition and structure. This work studies these properties by varying the structure of the constituting lipids in order to influence their interaction with high-density lipoprotein (HDL) particles. Various fluorescence-based techniques were applied to study lipid domains, membrane order, and the overall lateral as well as the molecule–internal glycerol region mobility in HDL–membrane interactions (i.e., binding and/or cargo transfer). The analysis of interactions with HDL particles and various lipid phases revealed that both fully fluid and some gel-phase lipids preferentially interact with HDL particles, although differences were observed in protein binding and cargo exchange. Both interactions were reduced with ordered lipid mixtures containing cholesterol. To investigate the mechanism, membranes were prepared from single-lipid components, enabling step-by-step modification of the lipid building blocks. On a biophysical level, the different mixtures displayed varying stiffness, fluidity, and hydrogen bond network changes. Increased glycerol mobility and a strengthened hydrogen bond network enhanced anchoring interactions, while fluid membranes with a reduced water network facilitated cargo transfer. In summary, the data indicate that different lipid classes are involved depending on the type of interaction, whether anchoring or cargo transfer. Full article

(This article belongs to the Special Issue Recent Advances in Biomembrane Models for Studying Interactions with Bio-/Molecules)

► Show Figures

Figure 1

17 pages, 4293 KiB

Open AccessArticle

A Gravity-Driven Membrane Bioreactor in Treating Real Fruit Juice Wastewater: Response Relationship Between Filtration Behavior and Microbial Community Evolution

by Dan Song, Haiyao Du, Shichun Chen, Xiaodie Han, Lu Wang, Yonggang Li, Caihong Liu, Wenjuan Zhang and Jun Ma

Membranes 2024, 14(12), 260; https://doi.org/10.3390/membranes14120260 - 6 Dec 2024

The issue of environmental pollution caused by wastewater discharge from fruit juice production has attracted increasing attention. However, the cost-effectiveness of conventional treatment technology remains insufficient. In this study, a gravity-driven membrane bioreactor (GDMBR) was developed to treat real fruit juice wastewater from [...] Read more.

The issue of environmental pollution caused by wastewater discharge from fruit juice production has attracted increasing attention. However, the cost-effectiveness of conventional treatment technology remains insufficient. In this study, a gravity-driven membrane bioreactor (GDMBR) was developed to treat real fruit juice wastewater from secondary sedimentation at pressures ranging from 0.01 to 0.04 MPa without requiring backwashing or chemical cleaning, with the aim of investigating flux development and contaminant removal under low-energy conditions. The results demonstrate an initial decrease in flux followed by stabilization during long-term filtration. Moreover, the stabilized flux level achieved with the GDMBR at pressures of 0.01 and 0.02 MPa was observed to surpass that obtained at 0.04 MPa, ranging from 4 to 4.5 L/m⁻² h⁻¹. The stability of flux was positively associated with the low membrane fouling resistance observed in the GDMBR system. Additionally, the GDMBR system provided remarkable efficiencies in removing the chemical oxygen demand (COD), biological oxygen demand (BOD), ammonia (NH₄⁺-N), and total nitrogen (TN), with average removal rates of 82%, 80%, 83%, and 79%, respectively. The high biological activity and microbial community diversity within the sludge and biofilm are expected to enhance its biodegradation potential, thereby contributing to the efficient removal of contaminants. Notably, a portion of total phosphorus (TP) can be effectively retained in the reactor, which highlighted the promising application of the GDMBR process for actual fruit juice wastewater based on these findings. Full article

(This article belongs to the Section Membrane Applications for Water Treatment)

► Show Figures

Figure 1

35 pages, 6121 KiB

Open AccessArticle

Reverse Osmosis Membrane Engineering: Multidirectional Analysis Using Bibliometric, Machine Learning, Data, and Text Mining Approaches

by Ersin Aytaç, Noman Khalid Khanzada, Yazan Ibrahim, Mohamed Khayet and Nidal Hilal

Membranes 2024, 14(12), 259; https://doi.org/10.3390/membranes14120259 - 6 Dec 2024

Membrane engineering is a complex field involving the development of the most suitable membrane process for specific purposes and dealing with the design and operation of membrane technologies. This study analyzed 1424 articles on reverse osmosis (RO) membrane engineering from the Scopus database [...] Read more.

Membrane engineering is a complex field involving the development of the most suitable membrane process for specific purposes and dealing with the design and operation of membrane technologies. This study analyzed 1424 articles on reverse osmosis (RO) membrane engineering from the Scopus database to provide guidance for future studies. The results show that since the first article was published in 1964, the domain has gained popularity, especially since 2009. Thin-film composite (TFC) polymeric material has been the primary focus of RO membrane experts, with 550 articles published on this topic. The use of nanomaterials and polymers in membrane engineering is also high, with 821 articles. Common problems such as fouling, biofouling, and scaling have been the center of work dedication, with 324 articles published on these issues. Wang J. is the leader in the number of published articles (73), while Gao C. is the leader in other metrics. Journal of Membrane Science is the most preferred source for the publication of RO membrane engineering and related technologies. Author social networks analysis shows that there are five core clusters, and the dominant cluster have 4 researchers. The analysis of sentiment, subjectivity, and emotion indicates that abstracts are positively perceived, objectively written, and emotionally neutral. Full article

(This article belongs to the Section Membrane Applications for Water Treatment)

► Show Figures

Figure 1

16 pages, 2048 KiB

Open AccessArticle

Effect of Monosaccharides Including Rare Sugars on the Bilayer Phase Behavior of Dimyristoylphosphatidylcholine

by Nobutake Tamai, Mei Kamiya, Nono Kiriyama, Masaki Goto, Kazuhiro Fukada and Hitoshi Matsuki

Membranes 2024, 14(12), 258; https://doi.org/10.3390/membranes14120258 - 3 Dec 2024

We observed bilayer phase transitions of dimyristoylphosphatidylcholine (DMPC) in aqueous solutions of four kinds of monosaccharides, namely, D-glucose, D-fructose, D-allose and D-psicose, using differential scanning calorimetry (DSC). D-allose (C3-epimer of D-glucose) and D-psicose (C3-epimer of D-fructose) are rare sugars. We performed DSC measurements [...] Read more.

We observed bilayer phase transitions of dimyristoylphosphatidylcholine (DMPC) in aqueous solutions of four kinds of monosaccharides, namely, D-glucose, D-fructose, D-allose and D-psicose, using differential scanning calorimetry (DSC). D-allose (C3-epimer of D-glucose) and D-psicose (C3-epimer of D-fructose) are rare sugars. We performed DSC measurements using two types of sugar-containing sample dispersions of the DMPC vesicles: one is a normal sample dispersion with no concentration asymmetry between the inside and outside of the vesicles and the other is an unusual sample dispersion with a concentration asymmetry. DSC measurements using normal sample dispersions with different sugar concentrations revealed that the temperatures and transition enthalpies of the pre- and main transition of the DMPC bilayer membrane did not significantly depend on the sugar concentration for all monosaccharides. DSC measurements using the unusual sample dispersions demonstrated that the concentration asymmetry caused the splitting of the endothermic peak of the main transition similarly irrespective of the sort of monosaccharides present. From all these DSC results, we conclude that (i) most monosaccharide molecules exist in the bulk water phase, (ii) no specific interaction depending on the molecular structure of each monosaccharide directly occurs between the DMPC and each monosaccharide molecule, and (iii) almost all the effects of the monosaccharides observed in this study are understandable as the general colligative properties of solutions. Full article

(This article belongs to the Section Biological Membranes)

► Show Figures

Graphical abstract

13 pages, 3581 KiB

Open AccessArticle

Effect of Ionic and Nonionic Compounds Structure on the Fluidity of Model Lipid Membranes: Computer Simulation and EPR Experiment

by Dariusz Man and Barbara Pytel

Membranes 2024, 14(12), 257; https://doi.org/10.3390/membranes14120257 - 3 Dec 2024

This article investigates the influence of dopant molecules on the structural and dynamic properties of lipid bilayers in liposomes, with a focus on the effects of dopant concentration, size, and introduced electric charge. Experimental studies were performed using electron paramagnetic resonance (EPR) spectroscopy [...] Read more.

This article investigates the influence of dopant molecules on the structural and dynamic properties of lipid bilayers in liposomes, with a focus on the effects of dopant concentration, size, and introduced electric charge. Experimental studies were performed using electron paramagnetic resonance (EPR) spectroscopy with spin probes, complemented by Monte Carlo simulations. Liposomes, formed via lecithin sonication, were doped with compounds of varying concentrations and analyzed using EPR spectroscopy to assess changes in membrane rigidity. Parallel simulations modeled the membrane’s surface layer as a system of electric dipoles on a 20 × 20 rectangular matrix. As in the EPR experiments, the simulation explored the effects of dopant molecules differing in size and charge, while gradually increasing their concentrations in the system. Minimum binding energy configurations were determined from the simulations. The results revealed a strong correlation between the EPR data and simulation outcomes, indicating a clear dependence of membrane stiffening on the concentration, size, and charge of dopant molecules. This effect was most pronounced at low dopant concentrations (~1–1.5% for q = 2 and 1.5–2% for q ≥ 3). No significant stiffening was observed for neutral molecules lacking charge. These findings offer valuable insights into the mechanisms of membrane modulation by dopants and provide a quantitative framework for understanding their impact on lipid bilayer properties. Full article

(This article belongs to the Section Biological Membranes)

► Show Figures

Figure 1

17 pages, 5451 KiB

Open AccessArticle

Role of DHA in a Physicochemical Study of a Model Membrane of Grey Matter

by Victor E. Cuenca, Viviana I. Pedroni and Marcela A. Morini

Membranes 2024, 14(12), 256; https://doi.org/10.3390/membranes14120256 - 3 Dec 2024

The present study investigates a multicomponent lipid system that simulates the neuronal grey matter membrane, employing molecular acoustics as a precise, straightforward, and cost-effective methodology. Given the significance of omega-3 polyunsaturated fatty acids in the functionality of cellular membranes, this research examines the [...] Read more.

The present study investigates a multicomponent lipid system that simulates the neuronal grey matter membrane, employing molecular acoustics as a precise, straightforward, and cost-effective methodology. Given the significance of omega-3 polyunsaturated fatty acids in the functionality of cellular membranes, this research examines the effects of reducing 1-palmitoyl-2-docosahexaenoylphosphatylcholine (PDPC) content on the compressibility and elasticity of the proposed membrane under physiological conditions. Our results align with bibliographic data obtained through other techniques, showing that as the proportion of PDPC increases in the grey matter membrane model, the system’s compressibility decreases, and the membrane’s elasticity increases, as evidenced by the reduction in the bulk modulus. These results could be interpreted in light of the emerging model of lipid rafts, in which esterified DHA infiltrates and remodels their architecture. We contend that the results obtained may serve as a bridge between biophysics and cellular biology. Full article

(This article belongs to the Section Biological Membranes)

► Show Figures

Figure 1

13 pages, 2140 KiB

Open AccessArticle

On a Specific Method for Characterizing Ion Exchange Membranes to Assess Their Functionality in Salinity Gradient Power Generation Through Reverse Electrodialysis, Including the Effect of Temperature

by Etienne Brauns and Joost Helsen

Membranes 2024, 14(12), 255; https://doi.org/10.3390/membranes14120255 - 3 Dec 2024

Salinity gradient power (SGP) by reverse electrodialysis is a promising method for converting SGP into electricity. Instead of the conventional approach of using seawater and freshwater, an alternative method involves using highly concentrated salt solutions (brines) alongside seawater or brackish water. Key factors [...] Read more.

Salinity gradient power (SGP) by reverse electrodialysis is a promising method for converting SGP into electricity. Instead of the conventional approach of using seawater and freshwater, an alternative method involves using highly concentrated salt solutions (brines) alongside seawater or brackish water. Key factors influencing SGP via reverse electrodialysis (SGP-RE) include the properties of ion exchange membranes, particularly their thickness. This paper outlines a practical experimental set-up that uses both a cation membrane (CM) and an anion membrane (AM). The system is configured with three compartments: two outer compartments filled with highly concentrated brine (HIGH) and a central compartment containing a lower concentration salt solution (LOW), akin to seawater. The compartments are separated by a CM on one side and an AM on the other. The ion transport rate from the HIGH compartments to the central LOW compartment allows for determining the overall ion transport coefficient for thin membranes. Measurements of ion flux and electrochemical voltage under dynamic equilibrium conditions also enable the estimation of the SGP-RE power density (W/m²). By controlling the temperature of the HIGH and LOW solutions, this experiment further investigates the significant impact of temperature on ion transport characteristics. Full article

(This article belongs to the Special Issue Research on Electrodialytic Processes)

► Show Figures

Figure 1

17 pages, 4524 KiB

Open AccessArticle

The Langmuir Monolayer as a Model Membrane System for Studying the Interactions of Poly(Butyl Cyanoacrylate) Nanoparticles with Phospholipids at the Air/Water Interface

by Georgi Yordanov, Ivan Minkov and Konstantin Balashev

Membranes 2024, 14(12), 254; https://doi.org/10.3390/membranes14120254 - 2 Dec 2024

Poly(butyl cyanoacrylate) (PBCA) nanoparticles have numerous applications, including drug and gene delivery, molecular imaging, and cancer therapy. To uncover the molecular mechanisms underlying their interactions with cell membranes, we utilized a Langmuir monolayer as a model membrane system. This approach enabled us to [...] Read more.

Poly(butyl cyanoacrylate) (PBCA) nanoparticles have numerous applications, including drug and gene delivery, molecular imaging, and cancer therapy. To uncover the molecular mechanisms underlying their interactions with cell membranes, we utilized a Langmuir monolayer as a model membrane system. This approach enabled us to investigate the processes of penetration and reorganization of PBCA nanoparticles when deposited in a phospholipid monolayer subphase. Atomic force microscopy (AFM) was employed to visualize Langmuir–Blodgett (LB) films of these nanoparticles. Additionally, we examined the state of a monolayer of Pluronic F68, a stabilizer of PBCA nanoparticles in suspension, by measuring the changes in relative surface area and surface potential over time in the barostatic regime following PBCA suspension spreading. Based on these findings, we propose a molecular mechanism for nanoparticle reorganization at the air–water interface. Full article

(This article belongs to the Section Biological Membranes)

► Show Figures

Figure 1

22 pages, 5684 KiB

Open AccessArticle

Microstructures of Directionally Solidified Nb₁₅Ti₅₅Fe₃₀ Alloy and Its Hydrogen Permeation Properties in the Presence of H₂S

by Erhu Yan, Guanzhong Huang, Kexiang Zhang, Lizhen Tao, Hongfei Chen, Zhijie Guo, Shuo Zhang, Yihao Wang, Zirui Zhou, Tangwei Li and Lixian Sun

Membranes 2024, 14(12), 253; https://doi.org/10.3390/membranes14120253 - 2 Dec 2024

Currently, the main limitations of Pd-coated Nb-TiFe dual-phase alloys include insufficient hydrogen permeability, susceptibility to hydrogen embrittlement (HE), and poor tolerance of H₂S poisoning. To address these issues, this study proposes a series of improvements. First, a novel Nb₁₅Ti [...] Read more.

Currently, the main limitations of Pd-coated Nb-TiFe dual-phase alloys include insufficient hydrogen permeability, susceptibility to hydrogen embrittlement (HE), and poor tolerance of H₂S poisoning. To address these issues, this study proposes a series of improvements. First, a novel Nb₁₅Ti₅₅Fe₃₀ alloy composed of a well-aligned Nb-TiFe eutectic was successfully prepared using directional solidification (DS) technology. After deposition with a Pd catalytic layer, this alloy exhibits high hydrogen permeability of 3.71 × 10⁻⁸ mol H₂ m⁻¹ s⁻¹ Pa^−1/2 at 673 K, which is 1.4 times greater than that of the as-cast counterpart. Second, to improve the H₂S corrosion resistance, a new Pd₈₈Au₁₂ catalytic layer was deposited on the surface using a multi-target magnetic control sputtering system. Upon testing in a 100 ppm H₂/H₂S mixture, this membrane exhibited better resistance to bulk sulfidation and a higher permeance recovery (ca. 58%) compared to pure Pd-coated membrane. This improvement is primarily due to the lower adsorption energies of the former with H₂S, which hinders the formation of bulk Pd₄S. Finally, the composition region of the Pd-Au catalytic membrane with high comprehensive performance was determined for the first time, revealing that optimal performance occurs at around 12–18 at.% Au. This finding explains how this composition maintains a balance between high H₂ permeability and excellent sulfur resistance. The significance of this study lies in its practical solutions for simultaneously improving hydrogen permeability and resistance to H₂S poisoning in Nb-based composite membranes. Full article

(This article belongs to the Section Membrane Fabrication and Characterization)

► Show Figures

Figure 1

16 pages, 8245 KiB

Open AccessArticle

System Dynamics Modeling of Scale Formation in Membrane Distillation Systems for Seawater and RO Brine Treatment

by Yonghyun Shin, Jaewuk Koo and Sangho Lee

Membranes 2024, 14(12), 252; https://doi.org/10.3390/membranes14120252 - 28 Nov 2024

To overcome the limitations of traditional Reverse Osmosis (RO) desalination, Membrane Distillation (MD) has gained attention as an effective solution for improving the treatment of seawater and RO brine. Despite its potential, the formation of inorganic scales, particularly calcium sulfate (CaSO₄), [...] Read more.

To overcome the limitations of traditional Reverse Osmosis (RO) desalination, Membrane Distillation (MD) has gained attention as an effective solution for improving the treatment of seawater and RO brine. Despite its potential, the formation of inorganic scales, particularly calcium sulfate (CaSO₄), continues to pose a major challenge. This research aims to explore the scaling mechanisms in MD systems through a combination of experimental analysis and dynamic modeling. Using real seawater and RO brine as feed sources, the scaling behavior was examined under various operational conditions, such as temperature and feed concentration. Optical Coherence Tomography (OCT) was utilized to monitor the real-time development of fouling layers, offering valuable insights into surface crystal formation processes. A System Dynamics Model (SDM) was created based on the experimental data to predict flux decline trends with precision. The model correlated well with experimental observations, highlighting key factors that drive scaling severity. This integrated approach deepens our understanding of scaling dynamics and provides actionable strategies to mitigate fouling in MD systems, thereby enhancing the efficiency and stability of MD desalination operations. Ultimately, this study underscores the potential of combining OCT with system dynamics modeling as a powerful approach for visualizing and validating scaling processes, offering a practical framework for optimizing MD performance and contributing to more sustainable desalination practices. Full article

(This article belongs to the Special Issue Advances in Membrane Distillation)

► Show Figures

Figure 1

15 pages, 4739 KiB

Open AccessArticle

Fouling and Chemical Cleaning Strategies for Submerged Ultrafiltration Membrane: Synchronized Bench-Scale, Full-Scale, and Engineering Tests

by Xiwang Zhu, Chengyue Fan, Yichen Fang, Wenqing Yu, Yawei Xie and Hongyuan Liu

Membranes 2024, 14(12), 251; https://doi.org/10.3390/membranes14120251 - 26 Nov 2024

This study investigated membrane fouling issues associated with the operation of a submerged ultrafiltration membrane in a drinking water treatment plant (DWTP) and optimized the associated chemical cleaning strategies. By analyzing the surface components of the membrane foulant and the compositions of the [...] Read more.

This study investigated membrane fouling issues associated with the operation of a submerged ultrafiltration membrane in a drinking water treatment plant (DWTP) and optimized the associated chemical cleaning strategies. By analyzing the surface components of the membrane foulant and the compositions of the membrane cleaning solution, the primary causes of membrane fouling were identified. Membrane fouling control strategies suitable for the DWTP were evaluated through chemical cleaning tests conducted for bench-scale, full-scale, and engineering cases. The results show that the membrane foulants were primarily composed of a mixture of inorganics and organics; the inorganics were mainly composed of Al and Si, while the organics were primarily humic acid (HA). Sodium citrate proved to be the most effective cleaning agent for inorganic fouling, which was mainly composed of Al, whereas sodium hypochlorite (NaClO) combined with sodium hydroxide (NaOH) showed the best removal efficiency for organic fouling, which predominantly consisted of HA and Si. However, sodium hypochlorite (NaClO) combined with sodium hydroxide (NaOH) showed the best removal efficiency for organic fouling and Si; organic fouling predominantly consisted of HA. Based on the bench-scale test results, flux recovery was verified in the full-scale system. Under a constant pressure of 30 kPa, the combined acid–alkali cleaning achieved the best flux recovery, restoring the flux from 22.8 L/(m²·h) to 66.75 L/(m²·h). In the engineering tests, combined acid–alkali cleaning yielded results consistent with those of the full-scale tests. In the practical engineering cleaning process, adopting a cleaning strategy of alkaline (NaClO + NaOH) cleaning followed by acidic (sodium citrate) cleaning can effectively solve the membrane fouling problem. Full article

(This article belongs to the Section Membrane Fabrication and Characterization)

► Show Figures

Figure 1

More Articles...

Submit to Membranes Review for Membranes

Journal Menu

Journal Browser

► Journal Browser

Highly Accessed Articles

View More...

Latest Books

More Books and Reprints...

E-Mail Alert

News

6 December 2024
MDPI INSIGHTS: The CEO's Letter #18 - MDPI UK, Basel Job Fair, CETEF'24

4 December 2024
685 MDPI Editors Named Highly Cited Researchers in 2024

5 November 2024
MDPI INSIGHTS: The CEO's Letter #17 - OA Week, Basel Open Day, Beijing Graphene Forum

More News & Announcements...

Topics

Propose a Topic

Topic in Applied Sciences, Clean Technol., Energies, Membranes, Polymers, Sustainability, Water

New Advances in Membrane Technology and Its Contribution to Sustainability Topic Editors: Patricia Luis Alconero, Bart Van der Bruggen
Deadline: 25 February 2025

Topic in Applied Sciences, Ceramics, Crystals, Membranes, Nanomaterials, Polymers

Broadband Dielectric Spectroscopy Fundamentals and Applications Topic Editors: Natália T. Correia, Teresa Viciosa, Hermínio P. Diogo
Deadline: 30 April 2025

Topic in Clean Technol., Membranes, Nanomaterials, Sustainability, Water

Removing Challenging Pollutants from Wastewater: Effective Approaches Topic Editors: Shuting Zhuang, Jiang-Bo Huo, Suping Yu
Deadline: 31 May 2025

Topic in Membranes, Polymers, Sustainability, Water, C

Towards Energy-Positive and Carbon-Neutral Technology for Wastewater Treatment and Reclamation Topic Editors: Xin Zhou, Dongqi Wang, Qiulai He, Xiaoyuan Zhang
Deadline: 31 August 2025

More Topics

Conferences

Announce Your Conference

26–29 August 2025 The 5th International Symposium on Frontiers in Molecular Science
Molecular Regulatory Mechanisms of Biological Function and Drug Discovery based on Protein Structure/Function Analysis

More Conferences...

Special Issues

Propose a Special Issue

Special Issue in Membranes

Ceramic Membranes for Removal of Emerging Pollutants Guest Editor: Chanhyuk Park
Deadline: 20 December 2024

Special Issue in Membranes

Artificial Intelligence and Machine Learning for Membrane Process Optimization and Membrane Design Guest Editors: Olawumi O. Sadare, Michael O. Daramola
Deadline: 20 December 2024

Special Issue in Membranes

Membranes in Ammonia Transport and Separation Guest Editor: Angela Kruth
Deadline: 20 December 2024

Special Issue in Membranes

Advances in Functional Separation Membranes for Pervaporation and Organic Solvent Nanofiltration Guest Editors: Shivshankar Chaudhari, Min Young Shon
Deadline: 20 December 2024

More Special Issues

Topical Collections

Topical Collection in Membranes

Feature Papers in Membrane Chemistry Collection Editors: Alberto Figoli, Philippe Knauth

Topical Collection in Membranes

Feature Papers in Membrane Surface and Interfaces Collection Editors: Konstantin Mikhelson, Beata Paczosa-Bator, Amir Razmjou

Topical Collection in Membranes

Feature Papers in Section 'Membrane Physics and Theory' Collection Editors: Sébastien Déon, Kang Xiao

Topical Collection in Membranes

Feature Papers in Biological Membrane Composition and Structures Collection Editor: Shiro Suetsugu

More Topical Collections

Back to TopTop