Mixed-Matrix Membranes and Polymeric Membranes 2.0

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Polymeric Membranes".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 24470

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Department of Chemical and Biomolecular Engineering, Sogang University, 35, Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea
Interests: organic and inorganic membranes; membrane nanostructure; bipolar membranes; biopolymer membranes; ion-conducting membranes; energy storage devices; fuel cell; reverse electrodialysis
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Special Issue Information

Dear Colleagues,

The industrial application of polymeric membranes is significantly growing day by day and has tremendous potential in delivering an efficient separation process. It has been almost 50 years since the first successful membrane was commercially utilized in the gas separation process. Since then, considerable progress has been made in the development of high-performance membranes for separation and purification processes. Mixed-matrix membranes are a high-performance membrane technology class that has elevated the membrane separation process to new heights. It is essential to finely tune the physical and chemical properties of the polymeric material to enhance the perm-selectivity and efficient ion transport capacity. It is a critical process to optimize the nano-material's size and shape with a polymer matrix to achieve a better interface. Therefore, several parameters need to be taken into consideration for developing high homogeneity between fillers and the matrix. The poor selectivity of ions and mechanical strength under stress conditions are the biggest challenges for researchers to overcome. Enormous efforts have been made to identify highly compatible organic or inorganic fillers for developing high-performance membranes for various applications.

The prime objective of this Special Issue is to provide a platform that allows authors to publish their findings on nanoengineering aspects of mixed matrix membranes. Authors working in designing advanced membrane material for separation and purification processes or energy storage applications can submit their findings to this issue. This issue will cover fundamental concepts and theories behind selecting appropriate filler material for the polymer matrix. The results deal with experimental observations or theoretical calculations developing defect-free interfaces between fillers and polymer matrices are most welcome.

Dr. Rahul Singh
Guest Editor

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Keywords

  • mixed-matrix membrane
  • porous framework
  • organic fillers
  • inorganic fillers
  • polymer electrolyte membrane
  • ion separation
  • purification
  • electrochemical systems

Published Papers (13 papers)

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Research

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16 pages, 11361 KiB  
Article
In Situ Formation of Silver Nanoparticles Induced by Cl-Doped Carbon Quantum Dots for Enhanced Separation and Antibacterial Performance of Nanofiltration Membrane
by Yi-Fang Mi, Jia-Li Liu, Wen Xia, Shu-Heng He and Bao-Qing Shentu
Membranes 2023, 13(8), 693; https://doi.org/10.3390/membranes13080693 - 25 Jul 2023
Cited by 2 | Viewed by 898
Abstract
Polyamide (PA) nanofiltration (NF) membranes suffer from biofouling, which will deteriorate their separation performance. In this study, we proposed a strategy to incorporate silver nanoparticles (Ag NPs) into PA NF membranes in situ, in order to simultaneously enhance water permeability and antibacterial performance. [...] Read more.
Polyamide (PA) nanofiltration (NF) membranes suffer from biofouling, which will deteriorate their separation performance. In this study, we proposed a strategy to incorporate silver nanoparticles (Ag NPs) into PA NF membranes in situ, in order to simultaneously enhance water permeability and antibacterial performance. The chloride-doped carbon quantum dots (Cl-CQDs) with photocatalytic performance were pre-embedded in the PA selective layer. Under visible light irradiation, the photogenerated charge carriers generated by Cl-CQDs rapidly transported to silver ions (Ag+ ions), resulting in the in situ formation of Ag NPs. The proposed strategy avoided the problem of aggregating Ag NPs, and the amount of Ag NPs on the membrane surfaces could be easily tuned by changing silver nitrate (AgNO3) concentrations and immersion times. These uniformly dispersed Ag NPs increased membrane hydrophilicity. Thus, the obtained thin film nanocomposite Ag NPs (TFN-Ag) membrane exhibited an improved water flux (31.74 L m−2 h−1), which was ~2.98 times that of the pristine PA membrane; meanwhile, the sodium sulfate (Na2SO4) rejection rate was 96.11%. The sterilization rates of the TFN-Ag membrane against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were 99.55% and 99.52%, respectively. Thus, this facile strategy simultaneously improved the permeability and antibacterial property of PA NF membranes. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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13 pages, 3060 KiB  
Article
Preparation of Thin Film Composite (TFC) Membrane with DESPs Interlayer and Its Forward Osmosis (FO) Performance for Organic Solvent Recovery
by Jingyi Liang, Hansheng Huang, Hao Zhang, Yanhui Wu and Yongbing Zhuang
Membranes 2023, 13(7), 688; https://doi.org/10.3390/membranes13070688 - 24 Jul 2023
Viewed by 975
Abstract
To explore the application of forward osmosis (FO) technology in the organic solvent recovery field, we prepared a new solvent-resistant triple layer thin film composite (TFC) membrane on the PI (polyimide) substrate. The deep eutectic supramolecular polymers (DESPs) interlayer was constructed on the [...] Read more.
To explore the application of forward osmosis (FO) technology in the organic solvent recovery field, we prepared a new solvent-resistant triple layer thin film composite (TFC) membrane on the PI (polyimide) substrate. The deep eutectic supramolecular polymers (DESPs) interlayer was constructed on the substrate to improve the separation performance and solvent resistance. DESPs interlayer was formed by mixing and heating with cyclodextrin as the hydrogen bond acceptor and L-malic acid as the hydrogen bond donor. The chemical changes, surface property and morphology of the composite membrane with DESPs interlayer were characterized. The separation performance and stability of the triple layer composite membrane in organic solvent FO were studied. For the monascorubrin-ethanol system, the permeation flux of TFC/DESPs5-PI membrane could reach 9.51 LMH while the rejection rate of monascorubrin was 98.4% (1.0 M LiCl/ethanol as draw solution), which was better than the pristine membrane. Therefore, this solvent-resistant triple layer composite FO membrane has good potential for the recovery of organic solvents. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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12 pages, 5496 KiB  
Article
Preparation of PVDF-PVP Composite Membranes for Oily Wastewater Treatment
by Sutrasno Kartohardjono, Ghofira Muna Khansa Salsabila, Azzahra Ramadhani, Irfan Purnawan and Woei Jye Lau
Membranes 2023, 13(6), 611; https://doi.org/10.3390/membranes13060611 - 20 Jun 2023
Cited by 2 | Viewed by 1466
Abstract
The oil and gas industry and related applications generate large quantities of oily wastewater, which can adversely affect the environment and human health if not properly handled. This study aims to prepare polyvinylidene fluoride (PVDF) membranes incorporated with polyvinylpyrrolidone (PVP) additives and utilize [...] Read more.
The oil and gas industry and related applications generate large quantities of oily wastewater, which can adversely affect the environment and human health if not properly handled. This study aims to prepare polyvinylidene fluoride (PVDF) membranes incorporated with polyvinylpyrrolidone (PVP) additives and utilize them to treat oily wastewater through the ultrafiltration (UF) process. Flat sheet membranes were prepared using PVDF dissolved in N,N-dimethylacetamide, followed by the addition of PVP ranging from 0.5 to 35 g. Characterization by scanning electron microscopy (SEM), water contact angle, Fourier transform infrared spectroscopy (FTIR), and mechanical strength tests were performed on the flat PVDF/PVP membranes to understand and compare the changes in the physical and chemical properties of the membranes. Prior to the UF process, oily wastewater was treated by a coagulation–flocculation process through a jar tester using polyaluminum chloride (PAC) as a coagulant. Based on the characterization of the membrane, the addition of PVP improves the physical and chemical properties of the membrane. The membrane’s pore size becomes larger, which can increase its permeability and flux. In general, the addition of PVP to the PVDF membrane can increase the porosity and decrease the water contact angle, thereby increasing the membrane’s hydrophilicity. With respect to filtration performance, the wastewater flux of the resultant membrane increases with increasing PVP content, but the rejections for TSS, turbidity, TDS, and COD are reduced. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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13 pages, 7267 KiB  
Article
Toward a Circular Bioeconomy: Exploring Pineapple Stem Starch Film as a Plastic Substitute in Single Use Applications
by Atitiya Namphonsane, Phattarakarn Suwannachat, Chin Hua Chia, Rungtiwa Wongsagonsup, Siwaporn Meejoo Smith and Taweechai Amornsakchai
Membranes 2023, 13(5), 458; https://doi.org/10.3390/membranes13050458 - 24 Apr 2023
Cited by 7 | Viewed by 2624
Abstract
In this study, biodegradable starch film was developed from pineapple stem waste as a substitute for non-biodegradable petroleum-based films for single-use applications where strength is not too demanding. High amylose starch from a pineapple stem was used as the matrix. Glycerol and citric [...] Read more.
In this study, biodegradable starch film was developed from pineapple stem waste as a substitute for non-biodegradable petroleum-based films for single-use applications where strength is not too demanding. High amylose starch from a pineapple stem was used as the matrix. Glycerol and citric acid were used as additives to adjust the ductility of the material. Glycerol content was fixed at 25% while that of citric acid varied from 0 to 15% by weight of starch. Films with a wide range of mechanical properties can be prepared. As more citric acid is added, the film becomes softer and weaker, and has greater elongation at the break. Properties range from a strength of about 21.5 MPa and 2.9% elongation to a strength of about 6.8 MPa and 35.7% elongation. An X-ray diffraction study showed that the films were semi-crystalline. The films were also found to be water-resistant and can be heat-sealed. An example of a single-use package was demonstrated. A soil burial test confirmed that the material was biodegradable and completely disintegrated into sizes smaller than 1 mm within one month. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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21 pages, 6930 KiB  
Article
Controlled Swelling of Monolithic Films as a Facile Approach to the Synthesis of UHMWPE Membranes
by Konstantin Pochivalov, Andrey Basko, Tatyana Lebedeva, Mikhail Yurov, Alexey Yushkin, Alexey Volkov and Sergei Bronnikov
Membranes 2023, 13(4), 422; https://doi.org/10.3390/membranes13040422 - 09 Apr 2023
Cited by 1 | Viewed by 1241
Abstract
A new method of fabricating porous membranes based on ultra-high molecular weight polyethylene (UHMWPE) by controlled swelling of the dense film was proposed and successfully utilized. The principle of this method is based on the swelling of non-porous UHMWPE film in organic solvent [...] Read more.
A new method of fabricating porous membranes based on ultra-high molecular weight polyethylene (UHMWPE) by controlled swelling of the dense film was proposed and successfully utilized. The principle of this method is based on the swelling of non-porous UHMWPE film in organic solvent at elevated temperatures, followed by its cooling and further extraction of organic solvent, resulting in the formation of the porous membrane. In this work, we used commercial UHMWPE film (thickness 155 μm) and o-xylene as a solvent. Either homogeneous mixtures of the polymer melt and solvent or thermoreversible gels with crystallites acting as crosslinks of the inter-macromolecular network (swollen semicrystalline polymer) can be obtained at different soaking times. It was shown that the porous structure and filtration performance of the membranes depended on the swelling degree of the polymer, which can be controlled by the time of polymer soaking in organic solvent at elevated temperature (106 °C was found to be the optimal temperature for UHMWPE). In the case of homogeneous mixtures, the resulting membranes possessed both large and small pores. They were characterized by quite high porosity (45–65% vol.), liquid permeance of 46–134 L m−2 h−1 bar−1, a mean flow pore size of 30–75 nm, and a very high crystallinity degree of 86–89% at a decent tensile strength of 3–9 MPa. For these membranes, rejection of blue dextran dye with a molecular weight of 70 kg/mol was 22–76%. In the case of thermoreversible gels, the resulting membranes had only small pores located in the interlamellar spaces. They were characterized by a lower crystallinity degree of 70–74%, a moderate porosity of 12–28%, liquid permeability of up to 12–26 L m−2 h−1 bar−1, a mean flow pore size of up to 12–17 nm, and a higher tensile strength of 11–20 MPa. These membranes demonstrated blue dextran retention of nearly 100%. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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16 pages, 3925 KiB  
Article
Novel Hydrophobic Ultrafiltration Membranes for Treatment of Oil-Contaminated Wastewater
by Tatsiana Hliavitskaya, Tatiana Plisko, Alexandr Bildyukevich, Alena Liubimova, Alena Shumskaya, Alexey Mikchalko, Alexandr A. Rogachev, Galina B. Melnikova and Svetlana A. Pratsenko
Membranes 2023, 13(4), 402; https://doi.org/10.3390/membranes13040402 - 01 Apr 2023
Viewed by 1428
Abstract
Cutting fluids are the main source of oily wastewater in the metalworking industry. This study deals with the development of antifouling composite hydrophobic membranes for treatment of oily wastewater. The novelty of this study is that a low energy electron-beam deposition technique was [...] Read more.
Cutting fluids are the main source of oily wastewater in the metalworking industry. This study deals with the development of antifouling composite hydrophobic membranes for treatment of oily wastewater. The novelty of this study is that a low energy electron-beam deposition technique was applied for a polysulfone (PSf) membrane with a molecular-weight cut-off of 300 kDa, which is promising for use in the treatment of oil-contaminated wastewater, by using polytetrafluoroethylene (PTFE) as target materials. The effect of the thickness of the PTFE layer (45, 660, and 1350 nm) on the structure, composition, and hydrophilicity of membranes was investigated using scanning electron microscopy, water contact angle (WCA) measurements, atomic force microscopy, and FTIR-spectroscopy. The separation and antifouling performance of the reference and modified membranes were evaluated during ultrafiltration of cutting fluid emulsions. It was found that the increase in the PTFE layer thickness results in the significant increase in WCA (from 56° up to 110–123° for the reference and modified membranes respectively) and decrease in surface roughness. It was found that cutting fluid emulsion flux of modified membranes was similar to the flux of the reference PSf-membrane (7.5–12.4 L·m−2·h−1 at 6 bar) while cutting fluid rejection (RCF) of modified membranes increased compared to the reference membrane (RCF = 58.4–93.3% for modified and RCF = 13% for the reference PSf membrane). It was established that despite the similar flux of cutting fluid emulsion, modified membranes demonstrate 5–6.5 times higher flux recovery ratio (FRR) compared to the reference membrane. The developed hydrophobic membranes were found to be highly efficient in oily wastewater treatment. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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18 pages, 30061 KiB  
Article
Thin-Film Composite Matrimid-Based Hollow Fiber Membranes for Oxygen/Nitrogen Separation by Gas Permeation
by Daniel González-Revuelta, Marcos Fallanza, Alfredo Ortiz and Daniel Gorri
Membranes 2023, 13(2), 218; https://doi.org/10.3390/membranes13020218 - 10 Feb 2023
Cited by 7 | Viewed by 2001
Abstract
In recent years, the need to reduce energy consumption worldwide to move towards sustainable development has led many of the conventional technologies used in the industry to evolve or to be replaced by new alternatives. Oxygen is a compound with diverse industrial and [...] Read more.
In recent years, the need to reduce energy consumption worldwide to move towards sustainable development has led many of the conventional technologies used in the industry to evolve or to be replaced by new alternatives. Oxygen is a compound with diverse industrial and medical applications. For this reason, obtaining it from air is one of the most interesting separations, traditionally performed by cryogenic distillation and pressure swing adsorption, two techniques which are very energetically expensive. In this sense, the implementation of membranes in a hollow fiber configuration is presented as a much more efficient alternative to carry out this separation. The aim of this work is to develop cost-effective multilayer hollow fiber composite membranes made of Matrimid and polydimethylsiloxane (PDMS) for the separation of oxygen and nitrogen from air. PDMS is used as a cover layer but can also enhance the performance of the membrane. In order to compare these two materials, three different configurations are studied. First, integral asymmetric Matrimid hollow fiber membranes were produced using the spinning method. Secondly, by using dip-coating method, a PDMS dense selective layer was deposited on a self-made polyvinylidene fluoride (PVDF) hollow fiber support. Finally, the performance of a dual-layer hollow fiber membrane of Matrimid and PDMS was studied. Membrane morphology was characterized by SEM and separation performance of the membranes was evaluated by mixed-gas permeation experiments. The novelty presented in this work is the manufacture of hollow fiber membranes and the way Matrimid is treated. This makes it possible to develop much thinner dense layers than in the case of flat-sheet membranes, which leads to higher permeance values. This is a key factor when implementing this technology on an industrial scale. Membranes prepared in this work were compared to the current state of the art, reporting quite good performance for the dual-layer membrane, reaching O2 permeance of 30.8 GPU and O2/N2 selectivity of 4.7, with a thickness of about 5–10 μm (counting both selective layers). In addition, the effect of operating temperature on the membrane permeances has been studied experimentally; we analyze its influence on the selectivity of the separation process. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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12 pages, 2781 KiB  
Article
Electrochemical Conversion of CO2 to CO Utilizing Quaternized Polybenzimidazole Anion Exchange Membrane
by Jingfeng Li, Zeyu Cao, Bo Zhang, Xinai Zhang, Jinchao Li, Yaping Zhang and Hao Duan
Membranes 2023, 13(2), 166; https://doi.org/10.3390/membranes13020166 - 29 Jan 2023
Cited by 2 | Viewed by 1526
Abstract
CO is a significant product of electrochemical CO2 reduction (ECR) which can be mixed with H2 to synthesize numerous hydrocarbons. Membranes, as separators, can significantly influence the performance of ECR. Herein, a series of quaternized polybenzimidazole (QAPBI) anion exchange membranes with [...] Read more.
CO is a significant product of electrochemical CO2 reduction (ECR) which can be mixed with H2 to synthesize numerous hydrocarbons. Membranes, as separators, can significantly influence the performance of ECR. Herein, a series of quaternized polybenzimidazole (QAPBI) anion exchange membranes with different quaternization degrees are prepared for application in ECR. Among all QAPBI membranes, the QAPBI-2 membrane exhibits optimized physico-chemical properties. In addition, the QAPBI-2 membrane shows higher a Faraday efficiency and CO partial current density compared with commercial Nafion 117 and FAA-3-PK-130 membranes, at −1.5 V (vs. RHE) in an H-type cell. Additionally, the QAPBI-2 membrane also has a higher Faraday efficiency and CO partial current density compared with Nafion 117 and FAA-3-PK-130 membranes, at −3.0 V in a membrane electrode assembly reactor. It is worth noting that the QAPBI-2 membrane also has excellent ECR stability, over 320 h in an H-type cell. This work illustrates a promising pathway to obtaining cost-effective membranes through a molecular structure regulation strategy for ECR application. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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12 pages, 1973 KiB  
Article
Morphological Analysis of Poly(4,4′-oxydiphenylene-pyromellitimide)-Based Organic Solvent Nanofiltration Membranes Formed by the Solution Method
by Tatyana E. Sukhanova, Andrey L. Didenko, Ilya L. Borisov, Tatyana S. Anokhina, Aleksey G. Ivanov, Anna S. Nesterova, Ilya A. Kobykhno, Alexey A. Yushkin, Vladimir V. Kudryavtsev and Alexey V. Volkov
Membranes 2022, 12(12), 1235; https://doi.org/10.3390/membranes12121235 - 07 Dec 2022
Cited by 3 | Viewed by 1280
Abstract
Poly-(4,4′-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, [...] Read more.
Poly-(4,4′-oxydiphenylene) pyromellitimide or Kapton is the most widely available polyimide with high chemical and thermal stability. It has great prospects for use as a membrane material for filtering organic media due to its complete insolubility. However, the formation of membranes based on it, at the moment, is an unsolved problem. The study corresponds to the rediscovery of poly(4,4′-oxydiphenylene–pyromellitimide)-based soluble copoly(urethane-imides) as membrane polymers of a new generation. It is shown that the physical structure of PUI films prepared by the solution method becomes porous after the removal of urethane blocks from the polymer, and the pore size varies depending on the conditions of thermolysis and subsequent hydrolysis of the membrane polymer. The film annealed at 170 °C with a low destruction degree of polycaprolactam blocks exhibits the properties of a nanofiltration membrane. It is stable in the aprotic solvent DMF and has a Remasol Brilliant Blue R retention coefficient of 95%. After the hydrolysis of thermally treated films in acidic media, ultrafiltration size 66–82 nm pores appear, which leads to an increase in the permeate flow by more than two orders of magnitude. This circumstance provides opportunities for controlling the membrane polymer structure for further optimization of the performance characteristics of filtration membranes based on it. Thus, we proposed a new preparation method of ultra- and nanofiltration membranes based on poly(4,4′-oxydiphenylene–pyromellitimide) that are stable in aprotic solvents. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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9 pages, 2123 KiB  
Article
Pulsed Vacuum Arc Deposition of Nitrogen-Doped Diamond-like Coatings for Long-Term Hydrophilicity of Electrospun Poly(ε-caprolactone) Scaffolds
by Semen Goreninskii, Yuri Yuriev, Artem Runts, Elisaveta Prosetskaya, Elizaveta Sviridova, Evgenii Plotnikov, Ksenia Stankevich and Evgeniy Bolbasov
Membranes 2022, 12(11), 1080; https://doi.org/10.3390/membranes12111080 - 31 Oct 2022
Viewed by 1239
Abstract
The surface hydrophobicity of poly(ε-caprolactone) electrospun scaffolds prevents their interactions with cells and tissue integration. Although plasma treatment of scaffolds enhances their hydrophilicity, this effect is temporary, and the hydrophobicity of the scaffolds is restored in about 30 days. In this communication, we [...] Read more.
The surface hydrophobicity of poly(ε-caprolactone) electrospun scaffolds prevents their interactions with cells and tissue integration. Although plasma treatment of scaffolds enhances their hydrophilicity, this effect is temporary, and the hydrophobicity of the scaffolds is restored in about 30 days. In this communication, we report a method for hydrophilization of poly(ε-caprolactone) electrospun scaffolds for more than 6 months. To that end, diamond-like coating was deposited on the surface of the scaffolds in a nitrogen atmosphere using pulsed vacuum arc deposition with sputtering of graphite target. This approach allows for a single-side hydrophilization of the scaffold (water contact angle of 22 ± 3° vs. 126 ± 2° for pristine PCL scaffold) and preserves its structure. With increased nitrogen pressure in the chamber, sp3-hybridized carbon content decreased twice (sp2/sp3 ratio decreased from 1.06 to 0.52), which demonstrates the possibility of tailoring the content of carbon in sp2 and sp3 hybridization state. Nitrogen content in the deposited coatings was found at 16.1 ± 0.9 at.%. In vitro tests with fibroblast cell culture did not reveal any cytotoxic compounds in sample extracts. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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13 pages, 1288 KiB  
Article
Cardo Polybenzimidazole (PBI-O-PhT) Based Membrane Reinforced with m-polybenzimidazole Electrospun Nanofiber Mat for HT-PEM Fuel Cell Applications
by Igor I. Ponomarev, Kirill M. Skupov, Alexander D. Modestov, Anna A. Lysova, Ivan I. Ponomarev and Elizaveta S. Vtyurina
Membranes 2022, 12(10), 956; https://doi.org/10.3390/membranes12100956 - 29 Sep 2022
Cited by 4 | Viewed by 1750
Abstract
The further development of high temperature polymer electrolyte membrane (HT-PEM) fuel cells largely depends on the improvement of all components of the membrane–electrode assembly (MEA), especially membranes and electrodes. To improve the membrane characteristics, the cardo-polybenzimidazole (PBI-O-PhT)-based polymer electrolyte complex doped with phosphoric [...] Read more.
The further development of high temperature polymer electrolyte membrane (HT-PEM) fuel cells largely depends on the improvement of all components of the membrane–electrode assembly (MEA), especially membranes and electrodes. To improve the membrane characteristics, the cardo-polybenzimidazole (PBI-O-PhT)-based polymer electrolyte complex doped with phosphoric acid is reinforced using an electrospun m-PBI mat. As a result, the PBI-O-PhT/es-m-PBInet · nH3PO4 reinforced membrane is obtained with hydrogen crossover values (~0.2 mA cm−2 atm−1), one order of magnitude lower than the one of the initial PBI-O-PhT membrane (~3 mA cm−2 atm−1) during HT-PEM fuel cell operation with Celtec®P1000 electrodes at 180 °C. Just as importantly, the reinforced membrane resistance was very close to the original one (65–75 mΩ cm2 compared to ~60 mΩ cm2). A stress test that consisted of 20 start–stops, which included cooling to the room temperature and heating back to 180 °C, was applied to the MEAs with the reinforced membrane. More stable operation for the HT-PEM fuel cell was shown when the Celtec®P1000 cathode (based on carbon black) was replaced with the carbon nanofiber cathode (based on the pyrolyzed polyacrylonitrile electrospun nanofiber mat). The obtained data confirm the enhanced characteristics of the PBI-O-PhT/es-m-PBInet · nH3PO4 reinforced membrane. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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Review

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22 pages, 5300 KiB  
Review
State-of-the-Art of Polymer/Fullerene C60 Nanocomposite Membranes for Water Treatment: Conceptions, Structural Diversity and Topographies
by Ayesha Kausar, Ishaq Ahmad, Malik Maaza and M. H. Eisa
Membranes 2023, 13(1), 27; https://doi.org/10.3390/membranes13010027 - 25 Dec 2022
Cited by 4 | Viewed by 3799
Abstract
To secure existing water resources is one of the imposing challenges to attain sustainability and ecofriendly world. Subsequently, several advanced technologies have been developed for water treatment. The most successful methodology considered so far is the development of water filtration membranes for desalination, [...] Read more.
To secure existing water resources is one of the imposing challenges to attain sustainability and ecofriendly world. Subsequently, several advanced technologies have been developed for water treatment. The most successful methodology considered so far is the development of water filtration membranes for desalination, ion permeation, and microbes handling. Various types of membranes have been industrialized including nanofiltration, microfiltration, reverse osmosis, and ultrafiltration membranes. Among polymeric nanocomposites, nanocarbon (fullerene, graphene, and carbon nanotubes)-reinforced nanomaterials have gained research attention owing to notable properties/applications. Here, fullerene has gained important stance amid carbonaceous nanofillers due to zero dimensionality, high surface areas, and exceptional physical properties such as optical, electrical, thermal, mechanical, and other characteristics. Accordingly, a very important application of polymer/fullerene C60 nanocomposites has been observed in the membrane sector. This review is basically focused on talented applications of polymer/fullerene nanocomposite membranes in water treatment. The polymer/fullerene nanostructures bring about numerous revolutions in the field of high-performance membranes because of better permeation, water flux, selectivity, and separation performance. The purpose of this pioneering review is to highlight and summarize current advances in the field of water purification/treatment using polymer and fullerene-based nanocomposite membranes. Particular emphasis is placed on the development of fullerene embedded into a variety of polymer membranes (Nafion, polysulfone, polyamide, polystyrene, etc.) and effects on the enhanced properties and performance of the resulting water treatment membranes. Polymer/fullerene nanocomposite membranes have been developed using solution casting, phase inversion, electrospinning, solid phase synthesis, and other facile methods. The structural diversity of polymer/fullerene nanocomposites facilitates membrane separation processes, especially for valuable or toxic metal ions, salts, and microorganisms. Current challenges and opportunities for future research have also been discussed. Future research on these innovative membrane materials may overwhelm design and performance-related challenging factors. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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34 pages, 4345 KiB  
Review
Current State-of-the-Art in Membrane Formation from Ultra-High Molecular Weight Polyethylene
by Andrey Basko and Konstantin Pochivalov
Membranes 2022, 12(11), 1137; https://doi.org/10.3390/membranes12111137 - 12 Nov 2022
Cited by 7 | Viewed by 2563
Abstract
One of the materials that attracts attention as a potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). One potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). The present review summarizes the results of studies carried out over [...] Read more.
One of the materials that attracts attention as a potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). One potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). The present review summarizes the results of studies carried out over the last 30 years in the field of preparation, modification and structure and property control of membranes made from ultrahigh molecular weight polyethylene. The review also presents a classification of the methods of membrane formation from this polymer and analyzes the conventional (based on the analysis of incomplete phase diagrams) and alternative (based on the analysis of phase diagrams supplemented by a boundary line reflecting the polymer swelling degree dependence on temperature) physicochemical concepts of the thermally induced phase separation (TIPS) method used to prepare UHMWPE membranes. It also considers the main ways to control the structure and properties of UHMWPE membranes obtained by TIPS and the original variations of this method. This review discusses the current challenges in UHMWPE membrane formation, such as the preparation of a homogeneous solution and membrane shrinkage. Finally, the article speculates about the modification and application of UHMWPE membranes and further development prospects. Thus, this paper summarizes the achievements in all aspects of UHMWPE membrane studies. Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes 2.0)
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