Membranes

10 pages, 2260 KiB

Open AccessArticle

Synthesis and Characterization of Gel Polymer Electrolyte Based on Epoxy Group via Cationic Ring-Open Polymerization for Lithium-Ion Battery

by Wei Zhang, Taewook Ryu, Sujin Yoon, Lei Jin, Giseok Jang, Wansu Bae, Whangi Kim, Faiz Ahmed and Hohyoun Jang

Membranes 2022, 12(4), 439; https://doi.org/10.3390/membranes12040439 - 18 Apr 2022

Cited by 9 | Viewed by 2829

Abstract

The polymer electrolytes are considered to be an alternative to liquid electrolytes for lithium-ion batteries because of their high thermal stability, flexibility, and wide applications. However, the polymer electrolytes have low ionic conductivity at room temperature due to the interfacial contact issue and [...] Read more.

The polymer electrolytes are considered to be an alternative to liquid electrolytes for lithium-ion batteries because of their high thermal stability, flexibility, and wide applications. However, the polymer electrolytes have low ionic conductivity at room temperature due to the interfacial contact issue and the growing of lithium dendrites between the electrolytes/electrodes. In this study, we prepared gel polymer electrolytes (GPEs) through an in situ thermal-induced cationic ring-opening strategy, using LiFSI as an initiator. As-synthesized GPEs were characterized with a series of technologies. The as-synthesized PNDGE 1.5 presented good thermal stability (up to 150 °C), low glass transition temperature (T_g < −40 °C), high ionic conductivity (>10⁻⁴ S/cm), and good interfacial contact with the cell components and comparable anodic oxidation voltage (4.0 V). In addition, PNGDE 1.5 exhibited a discharge capacity of 131 mAh/g after 50 cycles at 0.2 C and had a 92% level of coulombic efficiency. Herein, these results can contribute to developing of new polymer electrolytes and offer the possibility of good compatibility through the in situ technique for Li-ion batteries. Full article

(This article belongs to the Special Issue Polymer Electrolyte for Energy Devices)

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15 pages, 3738 KiB

Open AccessArticle

Hydrophilic and Positively Charged Polyvinylidene Fluoride Membranes for Water Treatment with Excellent Anti-Oil and Anti-Biocontamination Properties

by Zirui Wang, Shusu Shen, Linbin Zhang, Abdessamad Ben Hida and Ganwei Zhang

Membranes 2022, 12(4), 438; https://doi.org/10.3390/membranes12040438 - 18 Apr 2022

Cited by 11 | Viewed by 1984

Abstract

Membrane fouling limits the rapid development of membrane separations. In this study, a blend membrane containing polycationic liquid (P(BVImBr₁-co-PEGMA₁)) is presented that can improve the antifouling performance of polyvinylidene fluoride (PVDF) membranes. By mixing the polycationic liquid into PVDF, [...] Read more.

Membrane fouling limits the rapid development of membrane separations. In this study, a blend membrane containing polycationic liquid (P(BVImBr₁-co-PEGMA₁)) is presented that can improve the antifouling performance of polyvinylidene fluoride (PVDF) membranes. By mixing the polycationic liquid into PVDF, an improved membrane-surface hydrophilicity and enlarged membrane porosity were detected. The water contact angle decreased from 82° to 67°, the porosity enlarged from 7.22% to 89.74%, and the pure water flux improved from 0 to 631.68 L m⁻² h⁻¹. The blend membrane surfaces were found to be always positively charged at pH 3~10. By applying the membranes to the filtration of oil/water emulsion and bovine serum albumin (BSA) solution, they showed a very high rejection rate to pollutants in wastewater (99.4% to oil droplets and 85.6% to BSA). The positive membrane surface charge and the increased membrane hydrophilicity resulted in excellent antifouling performance, with the flux recovery rates of the dynamic filtration tests reaching 97.3% and 95.5%, respectively. Moreover, the blend membranes demonstrated very low BSA adhesion and could even kill S. aureus, showing excellent antifouling properties. Full article

(This article belongs to the Special Issue Advanced Membrane Technologies for Wastewater Treatment and Recycling)

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14 pages, 2910 KiB

Open AccessArticle

Edible Clusteroluminogenic Films Obtained from Starch of Different Botanical Origins for Food Packaging and Quality Management of Frozen Foods

by Wing-Fu Lai and Wing-Tak Wong

Membranes 2022, 12(4), 437; https://doi.org/10.3390/membranes12040437 - 18 Apr 2022

Cited by 17 | Viewed by 2649

Abstract

Starch is a naturally occurring material showing high potential for use in food packaging because of its low cost, natural abundance and high biodegradability. Over the years, different starch-based packaging films have been developed, but the impact of botanical sources on film performance [...] Read more.

Starch is a naturally occurring material showing high potential for use in food packaging because of its low cost, natural abundance and high biodegradability. Over the years, different starch-based packaging films have been developed, but the impact of botanical sources on film performance has rarely been exploited. Efforts devoted to exploiting the role played by the clusteroluminescence of starch in food packaging are also lacking. This study fills these gaps by comparing the properties of edible starch films generated from different botanical sources (including water chestnuts, maize and potatoes) in food packaging. Such films are produced by solution casting. They are highly homogeneous, with a thickness of 55–65 μm. Variations in the botanical sources of starch have no significant impact on the color parameters (including L*, a* and b*) and morphological features of the films but affect the water vapor permeability, maximum tensile strength and elongation at break. Starch films from water chestnut show the highest percentage of transmittance, whereas those from potatoes are the opaquest. No observable change in the intensity of clusteroluminescence occurs when a packaging bag generated from starch is used to package fresh or frozen chicken breast meat; however, a remarkable decline in the intensity of luminescence is noted when the frozen meat is thawed inside the bag. Our results reveal the impact of starch sources on the performance of starch films in food packaging and demonstrate the possibility of using the clusteroluminescence of starch as an indicator to reveal the state of packaged frozen food. Full article

(This article belongs to the Special Issue Advances on Bio-Based Materials for Food Packaging Applications)

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23 pages, 7313 KiB

Open AccessArticle

Effect of the Incorporation of ZIF-8@GO into the Thin-Film Membrane on Salt Rejection and BSA Fouling

by Elizabeth Gaobodiwe Masibi, Thollwana Andretta Makhetha and Richard Motlhaletsi Moutloali

Membranes 2022, 12(4), 436; https://doi.org/10.3390/membranes12040436 - 17 Apr 2022

Cited by 8 | Viewed by 2645

Abstract

A series of Zeolitic imidazole framework-8 (ZIF-8) clusters supported on graphene oxide (ZIF-8@GO) nanocomposites were prepared by varying the ratios of ZIF-8 to GO. The resultant nanocomposites were characterized using various techniques, such as Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray [...] Read more.

A series of Zeolitic imidazole framework-8 (ZIF-8) clusters supported on graphene oxide (ZIF-8@GO) nanocomposites were prepared by varying the ratios of ZIF-8 to GO. The resultant nanocomposites were characterized using various techniques, such as Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), Fourier Transform Infrared (FTIR) and Raman spectroscopy. These nanocomposites were incorporated into the thin film layer during interfacial polymerisation process of m-phenylenediamine (aqueous phase which contained the dispersed nanocomposites) and trimesoyl chloride (TMC, organic phase) at room temperature onto polyethersulfone (PES) ultrafiltration (UF) support membrane. The membrane surface morphology, cross section and surface roughness were characterized using SEM and AFM, respectively. Compared to the baseline membranes, the thin film nanofiltration (TFN) membranes exhibited improved pure water flux (from 1.66 up to 7.9 L.m⁻²h⁻¹), salt rejection (from 40 to 98%) and fouling resistance (33 to 88%). Optimum ZIF-8 to GO ratio was established as indicated in observed pure water flux, salt rejection and BSA fouling resistance. Therefore, a balance in hydrophilic and porous effect of the filler was observed to lead to this observed membrane behaviour suggesting that careful filler design can result in performance gain for thin film composite (TFC) membranes for water treatment application. Full article

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16 pages, 3560 KiB

Open AccessArticle

Development of Chitosan/Rice Husk-Based Silica Composite Membranes for Biodiesel Purification

by Saiful, Ulfa Riana, Muliadi Ramli, Muhammad Iqrammullah, Yanuardi Raharjo and Yusuf Wibisono

Membranes 2022, 12(4), 435; https://doi.org/10.3390/membranes12040435 - 17 Apr 2022

Cited by 6 | Viewed by 2330

Abstract

Inorganic–organic composite membranes (IOCMs) are an alternative separation method developed for their straightforward process, economic benefits, and ease of scaling up. The IOCMs in this study were prepared from a biopolymer chitosan matrix and rice husk-based silica filler to remove impurities from crude [...] Read more.

Inorganic–organic composite membranes (IOCMs) are an alternative separation method developed for their straightforward process, economic benefits, and ease of scaling up. The IOCMs in this study were prepared from a biopolymer chitosan matrix and rice husk-based silica filler to remove impurities from crude biodiesel. The IOCMs were prepared through phase inversions, in which the priorly prepared silica particles were dispersed in the dope solution of chitosan. The maximum loading of the silica particles was 60%, capable of reducing the soap level, free glycerol level, and acid number from 547.9 to 12.2 mg/L, 54 to 0.041%, and 2.02 to 1.12 mgKOH/g. These reduced impurity values have satisfied the standardized quality. The chemical composition and morphology of the IOCM was characterized using Fourier-transform infrared spectroscopy and scanning electron microscope–energy dispersive X-Ray spectroscopy. The IOCM water absorption-based porosity and swelling degree were studied as well. Further investigation using isothermal modeling revealed the adsorption dependency against the Sips model equation (R² = 0.99 and root-mean-square errors = 1.77 × 10⁻⁸). Even though regeneration is still a challenging factor in this study, the IOCM prepared from chitosan and rice husk-derived silica particles could be used in crude biodiesel purification. Full article

(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes)

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18 pages, 1868 KiB

Open AccessArticle

Water Sorption in Glassy Polyvinylpyrrolidone-Based Polymers

by Dominik Borrmann, Andreas Danzer and Gabriele Sadowski

Membranes 2022, 12(4), 434; https://doi.org/10.3390/membranes12040434 - 17 Apr 2022

Cited by 12 | Viewed by 2826

Abstract

Polyvinylpyrrolidone (PVP)-based polymers are excellent stabilizers for food supplements and pharmaceutical ingredients. However, they are highly hygroscopic. This study measured and modeled the water-sorption isotherms and water-sorption kinetics in thin PVP and PVP-co-vinyl acetate (PVPVA) films. The water sorption was measured at 25 [...] Read more.

Polyvinylpyrrolidone (PVP)-based polymers are excellent stabilizers for food supplements and pharmaceutical ingredients. However, they are highly hygroscopic. This study measured and modeled the water-sorption isotherms and water-sorption kinetics in thin PVP and PVP-co-vinyl acetate (PVPVA) films. The water sorption was measured at 25 °C from 0 to 0.9 RH, which comprised glassy and rubbery states of the polymer-water system. The sorption behavior of glassy polymers differs from that in the rubbery state. The perturbed-chain statistical associating fluid theory (PC-SAFT) accurately describes the water-sorption isotherms for rubbery polymers, whereas it was combined with the non-equilibrium thermodynamics of glassy polymers (NET-GP) approach to describe the water-sorption in the glassy polymers. Combined NET-GP and PC-SAFT modeling showed excellent agreement with the experimental data. Furthermore, the transitions between the PC-SAFT modeling with and without NET-GP were in reasonable agreement with the glass transition of the polymer-water systems. Furthermore, we obtained Fickian water diffusion coefficients in PVP and in PVPVA from the measured water-sorption kinetics over a broad range of humidities. Maxwell-Stefan and Fickian water diffusion coefficients yielded a non-monotonous water concentration dependency that could be described using the free-volume theory combined with PC-SAFT and NET-GP for calculating the free volume. Full article

(This article belongs to the Special Issue Fundamentals of Transport in Polymers and Membranes—Honorary Issue for Professor Giulio C. Sarti)

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15 pages, 1848 KiB

Open AccessArticle

Cost Profile of Membranes That Use Polymers of Intrinsic Microporosity (PIMs)

by Despina A. Gkika, Volkan Filiz, Sofia Rangou, George Z. Kyzas and Athanasios C. Mitrοpoulos

Membranes 2022, 12(4), 433; https://doi.org/10.3390/membranes12040433 - 17 Apr 2022

Viewed by 2673

Abstract

Assessing the financial impact of polymers of intrinsic microporosity, otherwise known as PIMs, at the lab scale has been impeded by the absence of a holistic approach that would envelop all related financial parameters, and most importantly any indirect costs, such as laboratory [...] Read more.

Assessing the financial impact of polymers of intrinsic microporosity, otherwise known as PIMs, at the lab scale has been impeded by the absence of a holistic approach that would envelop all related financial parameters, and most importantly any indirect costs, such as laboratory accidents that have been consistently neglected and undervalued in past assessments. To quantify the cost of PIMs in relation to the risks befalling a laboratory, an innovative cost evaluation approach was designed. This approach consists of three stages. Firstly, a two-fold “window of opportunity” (WO) theory is suggested, dividing the total cost profile into two segments, followed up by a qualitative risk analysis to establish the potential cost components. The last stage builds on a total cost of ownership model, incorporating the two types of WO. The total cost of ownership (TCO) approach was selected to ascertain the costs and construct the cost profile of PIMs, according to laboratory experimental data. This model was applied to the synthesis and physicochemical characterization processes. The quantitative analysis revealed that the most influential parameters for synthesis are accidents and energy costs. This is in contrast with the physicochemical characterization process, where the most important determinant is the energy cost. Full article

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15 pages, 4260 KiB

Open AccessArticle

Evaluation of the Specific Energy Consumption of Sea Water Reverse Osmosis Integrated with Membrane Distillation and Pressure–Retarded Osmosis Processes with Theoretical Models

by Shao-Chi Tsai, Wei-Zhi Huang, Geng-Sheng Lin, Zhen Wang, Kuo-Lun Tung and Ching-Jung Chuang

Membranes 2022, 12(4), 432; https://doi.org/10.3390/membranes12040432 - 16 Apr 2022

Cited by 6 | Viewed by 2522

Abstract

In this study, theoretical models for specific energy consumption (SEC) were established for water recovery in different integrated processes, such as RO-PRO, RO-MD and RO-MD-PRO. Our models can evaluate SEC under different water recovery conditions and for various proportions of supplied waste heat. [...] Read more.

In this study, theoretical models for specific energy consumption (SEC) were established for water recovery in different integrated processes, such as RO-PRO, RO-MD and RO-MD-PRO. Our models can evaluate SEC under different water recovery conditions and for various proportions of supplied waste heat. Simulation results showed that SEC in RO increases with the water recovery rate when the rate is greater than 30%. For the RO-PRO process, the SEC also increases with the water recovery rate when the rate is higher than 38%, but an opposite trend can be observed at lower water recovery rates. If sufficient waste heat is available as the heat source for MD, the integration of MD with the RO or RO-PRO process can significantly reduce SEC. If the total water recovery rate is 50% and MD accounts for 10% of the recovery when sufficient waste heat is available, the SEC values of RO, RO-PRO, RO-MD and RO-MD-PRO are found to be 2.28, 1.47, 1.75 and 0.67 kWh/m³, respectively. These critical analyses provide a road map for the future development of process integration for desalination. Full article

(This article belongs to the Special Issue Special Issue in Honor of Professor Ahmad Fauzi Ismail)

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25 pages, 8123 KiB

Open AccessArticle

Effect of Different Hot-Pressing Pressure and Temperature on the Performance of Titanium Mesh-Based MEA for DMFC

by Xingxing Wang, Yujie Zhang, Yu Zhu, Shuaishuai Lv, Hongjun Ni, Yelin Deng and Yinnan Yuan

Membranes 2022, 12(4), 431; https://doi.org/10.3390/membranes12040431 - 16 Apr 2022

Cited by 6 | Viewed by 3235

Abstract

The hot-pressing process of the membrane electrode assembly (MEA) is one of the research hotspots in the field of the fuel cell. To obtain suitable titanium mesh-based MEA hot pressing process parameters, titanium mesh was used as electrode substrate material. The anode and [...] Read more.

The hot-pressing process of the membrane electrode assembly (MEA) is one of the research hotspots in the field of the fuel cell. To obtain suitable titanium mesh-based MEA hot pressing process parameters, titanium mesh was used as electrode substrate material. The anode and cathode of MEA were prepared by the drip-coated method, and the titanium mesh-based MEA was prepared under different hot-pressing pressure and temperature, respectively. The performance of titanium mesh-based MEA was studied by morphological observation, elemental analysis, thickness measurement, single cell test and numerical fitting analysis. The results demonstrated that: with increasing hot-pressing pressure from 0 MPa to 10 MPa, the forming thickness of titanium mesh-based MEA is getting thin gradually, and the peak power density of titanium mesh-based MEA first increased and then gradually decreased; with increasing hot-pressing temperature from 115 °C to 155 °C, the peak power density of titanium mesh-based MEA enhanced at the beginning and then also gradually decreased. Under the premise of a hot-pressing time of 180 s and the optimal operating temperature of DMFC of 60 °C, the appropriate hot-pressing process conditions of titanium mesh-based MEA are a hot-pressing pressure of 5 MPa and a hot-pressing temperature of 135 °C. The results can provide a technological reference for the preparation of titanium mesh MEA for DMFC. Full article

(This article belongs to the Special Issue Membrane Electrode Assembly (MEA))

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20 pages, 4661 KiB

Open AccessArticle

Intermediate Temperature PEFC’s with Nafion^® 211 Membrane Electrolytes: An Experimental and Numerical Study

by Oliver Fernihough, Mohammed S. Ismail and Ahmad El-kharouf

Membranes 2022, 12(4), 430; https://doi.org/10.3390/membranes12040430 - 15 Apr 2022

Cited by 5 | Viewed by 2740

Abstract

This paper evaluates the performance of Nafion 211 at elevated temperatures up to 120 °C using an experimentally validated model. Increasing the fuel cell operating temperature could have many key benefits at the cell and system levels. However, current research excludes this due [...] Read more.

This paper evaluates the performance of Nafion 211 at elevated temperatures up to 120 °C using an experimentally validated model. Increasing the fuel cell operating temperature could have many key benefits at the cell and system levels. However, current research excludes this due to issues with membrane durability. Modelling is used to investigate complex systems to gain further information that is challenging to obtain experimentally. Nafion 211 is shown to have some interesting characteristics at elevated temperatures previously unreported, the first of which is that the highest performance reported is at 100 °C and 100% relative humidity. The model was trained on the experimental data and then used to predict the behaviour in the membrane region to understand how the fuel cell performs at varying temperatures and pressures. The model showed that the best membrane performance comes from a 100 °C operating temperature, with much better performance yielded from a higher pressure of 3 bar. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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19 pages, 1576 KiB

Open AccessReview

State-of-the-Art Review on the Application of Membrane Bioreactors for Molecular Micro-Contaminant Removal from Aquatic Environment

by My-Linh Nguyen, Ali Taghvaie Nakhjiri, Mehnaz Kamal, Abdullah Mohamed, Mohammed Algarni, Subbotina Tatyana Yu, Fu-Ming Wang and Chia-Hung Su

Membranes 2022, 12(4), 429; https://doi.org/10.3390/membranes12040429 - 15 Apr 2022

Cited by 16 | Viewed by 2488

Abstract

In recent years, the emergence of disparate micro-contaminants in aquatic environments such as water/wastewater sources has eventuated in serious concerns about humans’ health all over the world. Membrane bioreactor (MBR) is considered a noteworthy membrane-based technology, and has been recently of great interest [...] Read more.

In recent years, the emergence of disparate micro-contaminants in aquatic environments such as water/wastewater sources has eventuated in serious concerns about humans’ health all over the world. Membrane bioreactor (MBR) is considered a noteworthy membrane-based technology, and has been recently of great interest for the removal micro-contaminants. The prominent objective of this review paper is to provide a state-of-the-art review on the potential utilization of MBRs in the field of wastewater treatment and micro-contaminant removal from aquatic/non-aquatic environments. Moreover, the operational advantages of MBRs compared to other traditional technologies in removing disparate sorts of micro-contaminants are discussed to study the ways to increase the sustainability of a clean water supplement. Additionally, common types of micro-contaminants in water/wastewater sources are introduced and their potential detriments on humans’ well-being are presented to inform expert readers about the necessity of micro-contaminant removal. Eventually, operational challenges towards the industrial application of MBRs are presented and the authors discuss feasible future perspectives and suitable solutions to overcome these challenges. Full article

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10 pages, 2296 KiB

Open AccessArticle

Membrane Repairing Capability of Non-Small Cell Lung Cancer Cells Is Regulated by Drug Resistance and Epithelial-Mesenchymal-Transition

by Xingyu Xia, Hanbo Yang, Dennis Wai-Yin Au, Syrus Pak-Hei Lai, Yuan Lin and William Chi-Shing Cho

Membranes 2022, 12(4), 428; https://doi.org/10.3390/membranes12040428 - 15 Apr 2022

Cited by 1 | Viewed by 1729

Abstract

The plasma membrane separates the interior of the cells from the extracellular fluid and protects the cell from disruptive external factors. Therefore, the self-repairing capability of the membrane is crucial for cells to maintain homeostasis and survive in a hostile environment. Here, we [...] Read more.

The plasma membrane separates the interior of the cells from the extracellular fluid and protects the cell from disruptive external factors. Therefore, the self-repairing capability of the membrane is crucial for cells to maintain homeostasis and survive in a hostile environment. Here, we found that micron-sized membrane pores induced by cylindrical atomic force microscope probe puncture resealed significantly (~1.3–1.5 times) faster in drug-resistant non-small cell lung cancer (NSCLC) cell lines than in their drug-sensitive counterparts. Interestingly, we found that such enhanced membrane repairing ability was due to the overexpression of annexin in drug-resistant NSCLC cells. In addition, a further ~50% reduction in membrane resealing time (i.e., from ~23 s to ~13 s) was observed through the epithelial-mesenchymal-transition, highlighting the superior viability and potential of highly aggressive tumor cells using membrane resealing as an indicator for assessing the drug-resistivity and pathological state of cancer. Full article

(This article belongs to the Section Biological Membrane Dynamics and Computation)

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17 pages, 1726 KiB

Open AccessReview

A Short Overview of Biological Fuel Cells

by Ivan Vito Ferrari, Luca Pasquini, Riccardo Narducci, Emanuela Sgreccia, Maria Luisa Di Vona and Philippe Knauth

Membranes 2022, 12(4), 427; https://doi.org/10.3390/membranes12040427 - 15 Apr 2022

Cited by 9 | Viewed by 3202

Abstract

This short review summarizes the improvements on biological fuel cells (BioFCs) with or without ionomer separation membrane. After a general introduction about the main challenges of modern energy management, BioFCs are presented including microbial fuel cells (MFCs) and enzymatic fuel cells (EFCs). The [...] Read more.

This short review summarizes the improvements on biological fuel cells (BioFCs) with or without ionomer separation membrane. After a general introduction about the main challenges of modern energy management, BioFCs are presented including microbial fuel cells (MFCs) and enzymatic fuel cells (EFCs). The benefits of BioFCs include the capability to derive energy from waste-water and organic matter, the possibility to use bacteria or enzymes to replace expensive catalysts such as platinum, the high selectivity of the electrode reactions that allow working with less complicated systems, without the need for high purification, and the lower environmental impact. In comparison with classical FCs and given their lower electrochemical performances, BioFCs have, up to now, only found niche applications with low power needs, but they could become a green solution in the perspective of sustainable development and the circular economy. Ion exchange membranes for utilization in BioFCs are discussed in the final section of the review: they include perfluorinated proton exchange membranes but also aromatic polymers grafted with proton or anion exchange groups. Full article

(This article belongs to the Special Issue Membranes in Our Life: An Honorary Special Issue Dedicated to Prof. Enrico Drioli on the Occasion of his 80th Birthday)

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19 pages, 22308 KiB

Open AccessArticle

Flat PVDF Membrane with Enhanced Hydrophobicity through Alkali Activation and Organofluorosilanisation for Dissolved Methane Recovery

by Ramón Jiménez-Robles, Beatriz María Moreno-Torralbo, Jose David Badia, Vicente Martínez-Soria and Marta Izquierdo

Membranes 2022, 12(4), 426; https://doi.org/10.3390/membranes12040426 - 15 Apr 2022

Cited by 6 | Viewed by 2365

Abstract

A three-step surface modification consisting of activation with NaOH, functionalisation with a silica precursor and organofluorosilane mixture (FSi_T), and curing was applied to a poly(vinylidene fluoride) (PVDF) membrane for the recovery of dissolved methane (D-CH₄) from aqueous streams. Based [...] Read more.

A three-step surface modification consisting of activation with NaOH, functionalisation with a silica precursor and organofluorosilane mixture (FSi_T), and curing was applied to a poly(vinylidene fluoride) (PVDF) membrane for the recovery of dissolved methane (D-CH₄) from aqueous streams. Based on the results of a statistical experimental design, the main variables affecting the water contact angle (WCA) were the NaOH concentration and the FSi_T ratio and concentration used. The maximum WCA of the modified PVDF (mPVDF_max) was >140° at a NaOH concentration of 5%, an FSi_T ratio of 0.55 and an FSi_T concentration of 7.2%. The presence of clusters and a lower surface porosity of mPVDF was detected by FESEM analysis. In long-term stability tests with deionised water at 21 L h⁻¹, the WCA of the mPVDF decreased rapidly to around 105°, similar to that of pristine nmPVDF. In contrast, the WCA of the mPVDF was always higher than that of nmPVDF in long-term operation with an anaerobic effluent at 3.5 L h⁻¹ and showed greater mechanical stability, since water breakthrough was detected only with the nmPVDF membrane. D-CH₄ degassing tests showed that the increase in hydrophobicity induced by the modification procedure increased the D-CH₄ removal efficiency but seemed to promote fouling. Full article

(This article belongs to the Special Issue State-of-the-Art Membrane Science and Technology in the Iberian Peninsula 2021-2022)

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17 pages, 2982 KiB

Open AccessArticle

MOF/Polymer Mixed-Matrix Membranes Preparation: Effect of Main Synthesis Parameters on CO₂/CH₄ Separation Performance

by Harun Kulak, Raymond Thür and Ivo F. J. Vankelecom

Membranes 2022, 12(4), 425; https://doi.org/10.3390/membranes12040425 - 14 Apr 2022

Cited by 10 | Viewed by 3922

Abstract

Design and preparation of mixed-matrix membranes (MMMs) with minimum defects and high performance for desired gas separations is still challenging as it depends on a variety of MMM synthesis parameters. In this study, 6FDA-DAM:DABA based MMMs using MOF-808 as filler were prepared to [...] Read more.

Design and preparation of mixed-matrix membranes (MMMs) with minimum defects and high performance for desired gas separations is still challenging as it depends on a variety of MMM synthesis parameters. In this study, 6FDA-DAM:DABA based MMMs using MOF-808 as filler were prepared to examine the impact of multiple variables on the preparation process of MMMs, including variation in polymer concentration, filler loading, volume of solution cast per membrane area, solvent type used and solvent evaporation rate, and to identify their impact on the CO₂/CH₄ separation performance of these membranes. Solvent evaporation rate proved to be the most critical synthesis parameter, directly influencing the performance and visual appearance of the membranes. Although less dominantly influencing the MMM performance, polymer concentration and solution volume also had an important role via control over the casting solution viscosity, particle agglomeration, and particle settling rate. Among all solvents studied, MMMs prepared with chloroform led to the best performance for this polymer-filler system. Chloroform-based MMMs containing 10 and 30 wt.% MOF-808 showed 73% and 62% increase in CO₂ permeability, respectively, without a decrease in separation factor compared to unfilled membranes. The results indicate that enhanced gas separation performance of MMMs strongly depends on the cumulative effect of various synthesis parameters rather than individual impact, thus requiring a system-specific design and optimization. Full article

(This article belongs to the Special Issue Advanced Membranes for Carbon Capture 2021)

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21 pages, 8158 KiB

Open AccessArticle

Long-Term Treatment of Highly Saline Brine in a Direct Contact Membrane Distillation (DCMD) Pilot Unit Using Polyethylene Membranes

by Haneen Abdelrazeq, Majeda Khraisheh and Mohammad K. Hassan

Membranes 2022, 12(4), 424; https://doi.org/10.3390/membranes12040424 - 14 Apr 2022

Cited by 6 | Viewed by 2464

Abstract

Membrane distillation (MD) is an attractive separation process for wastewater treatment and desalination. There are continuing challenges in implementing MD technologies at a large industrial scale. This work attempts to investigate the desalination performance of a pilot-scale direct contact membrane distillation (DCMD) system [...] Read more.

Membrane distillation (MD) is an attractive separation process for wastewater treatment and desalination. There are continuing challenges in implementing MD technologies at a large industrial scale. This work attempts to investigate the desalination performance of a pilot-scale direct contact membrane distillation (DCMD) system using synthetic thermal brine mimicking industrial wastewater in the Gulf Cooperation Council (GCC). A commercial polyethylene membrane was used in all tests in the DCMD pilot unit. Long-term performance exhibited up to 95.6% salt rejection rates using highly saline feed (75,500 ppm) and 98% using moderate saline feed (25,200 ppm). The results include the characterization of the membrane surface evolution during the tests, the fouling determination, and the assessment of the energy consumption. The fouling effect of the polyethylene membrane was studied using Humic acid (HA) as the feed for the whole DCMD pilot unit. An optimum specific thermal energy consumption (STEC) reduction of 10% was achieved with a high flux recovery ratio of 95% after 100 h of DCMD pilot operation. At fixed operating conditions for feed inlet temperature of 70 °C, a distillate inlet temperature of 20 °C, with flowrates of 70 l/h for both streams, the correlations were as high as 0.919 between the pure water flux and water contact angle, and 0.963 between the pure water flux and salt rejection, respectively. The current pilot unit study provides better insight into existing thermal desalination plants with an emphasis on specific energy consumption (SEC). The results of this study may pave the way for the commercialization of such filtration technology at a larger scale in global communities. Full article

(This article belongs to the Special Issue Advances in Membrane Science for Sustainable Future)

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18 pages, 5529 KiB

Open AccessEditor’s ChoiceArticle

Novel Sandwich-Structured Hollow Fiber Membrane for High-Efficiency Membrane Distillation and Scale-Up for Pilot Validation

by Marn Soon Qua, Yan Zhao, Junyou Zhang, Sebastian Hernandez, Aung Thet Paing, Karikalan Mottaiyan, Jian Zuo, Adil Dhalla, Tai-Shung Chung and Chakravarthy Gudipati

Membranes 2022, 12(4), 423; https://doi.org/10.3390/membranes12040423 - 14 Apr 2022

Cited by 4 | Viewed by 2637

Abstract

Hollow fiber membranes were produced from a commercial polyvinylidene fluoride (PVDF) polymer, Kynar HSV 900, with a unique sandwich structure consisting of two sponge-like layers connected to the outer and inner skin layers while the middle layer comprises macrovoids. The sponge-like layer allows [...] Read more.

Hollow fiber membranes were produced from a commercial polyvinylidene fluoride (PVDF) polymer, Kynar HSV 900, with a unique sandwich structure consisting of two sponge-like layers connected to the outer and inner skin layers while the middle layer comprises macrovoids. The sponge-like layer allows the membrane to have good mechanical strength even at low skin thickness and favors water vapor transportation during vacuum membrane distillation (VMD). The middle layer with macrovoids helps to significantly reduce the trans-membrane resistance during water vapor transportation from the feed side to the permeate side. Together, these novel structural characteristics are expected to render the PVDF hollow fiber membranes more efficient in terms of vapor flux as well as mechanical integrity. Using the chemistry and process conditions adopted from previous work, we were able to scale up the membrane fabrication from a laboratory scale of 1.5 kg to a manufacturing scale of 50 kg with consistent membrane performance. The produced PVDF membrane, with a liquid entry pressure (LEPw) of >3 bar and a pure water flux of >30 L/m²·hr (LMH) under VMD conditions at 70–80 °C, is perfectly suitable for next-generation high-efficiency membranes for desalination and industrial wastewater applications. The technology translation efforts, including membrane and module scale-up as well as the preliminary pilot-scale validation study, are discussed in detail in this paper. Full article

(This article belongs to the Special Issue Advanced Membrane Technologies for Wastewater Treatment and Recycling)

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15 pages, 7457 KiB

Open AccessArticle

Effect of UF Membrane Rotation on Filtration Performance Using High Concentration Latex Emulsion Solution

by Kazutaka Takata and Katsuyoshi Tanida

Membranes 2022, 12(4), 422; https://doi.org/10.3390/membranes12040422 - 14 Apr 2022

Cited by 4 | Viewed by 1496

Abstract

A high shear rate can be applied to fluid near a membrane surface by rotating the membrane. This shear rate enables higher permeate flux and higher concentration operation when compared with a conventional cross-flow membrane since fouling and/or concentration polarization are reduced. The [...] Read more.

A high shear rate can be applied to fluid near a membrane surface by rotating the membrane. This shear rate enables higher permeate flux and higher concentration operation when compared with a conventional cross-flow membrane since fouling and/or concentration polarization are reduced. The purpose of this study was to clarify the relationship between the fluid behavior and membrane separation characteristics of a rotating membrane surface when a latex aqueous solution was used. Due to the synergistic effect of particle removal by the centrifugal forces generated by the rotation of the membrane and the reduction in the thickness of the velocity boundary layer, membrane filtration of high-concentration slurry, which is difficult to dewater by the cross-flow method, is possible. The experimental data using an aqueous latex solution with a wide range of slurry concentrations and various membrane diameters are well correlated using a shear rate derived from the boundary layer theory. It is thus confirmed that the shear rate can be used as a design and operating parameter to define the membrane filtration characteristics. Full article

(This article belongs to the Special Issue Membrane Separation Techniques: Advances, Challenges, and Future Avenues)

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13 pages, 2457 KiB

Open AccessArticle

Multiparameter Neural Network Modeling of Facilitated Transport Mixed Matrix Membranes for Carbon Dioxide Removal

by Rizwan Nasir, Humbul Suleman and Khuram Maqsood

Membranes 2022, 12(4), 421; https://doi.org/10.3390/membranes12040421 - 14 Apr 2022

Cited by 5 | Viewed by 1910

Abstract

Membranes for carbon capture have improved significantly with various promoters such as amines and fillers that enhance their overall permeance and selectivity toward a certain particular gas. They require nominal energy input and can achieve bulk separations with lower capital investment. The results [...] Read more.

Membranes for carbon capture have improved significantly with various promoters such as amines and fillers that enhance their overall permeance and selectivity toward a certain particular gas. They require nominal energy input and can achieve bulk separations with lower capital investment. The results of an experiment-based membrane study can be suitably extended for techno-economic analysis and simulation studies, if its process parameters are interconnected to various membrane performance indicators such as permeance for different gases and their selectivity. The conventional modelling approaches for membranes cannot interconnect desired values into a single model. Therefore, such models can be suitably applicable to a particular parameter but would fail for another process parameter. With the help of artificial neural networks, the current study connects the concentrations of various membrane materials (polymer, amine, and filler) and the partial pressures of carbon dioxide and methane to simultaneously correlate three desired outputs in a single model: CO₂ permeance, CH₄ permeance, and CO₂/CH₄ selectivity. These parameters help predict membrane performance and guide secondary parameters such as membrane life, efficiency, and product purity. The model results agree with the experimental values for a selected membrane, with an average absolute relative error of 6.1%, 4.2%, and 3.2% for CO₂ permeance, CH₄ permeance, and CO₂/CH₄ selectivity, respectively. The results indicate that the model can predict values at other membrane development conditions. Full article

(This article belongs to the Section Membrane Processing and Engineering)

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15 pages, 2692 KiB

Open AccessArticle

Effect of Operational Parameters on the Removal of Carbamazepine and Nutrients in a Submerged Ceramic Membrane Bioreactor

by Khanh-Chau Dao, Chih-Chi Yang, Ku-Fan Chen and Yung-Pin Tsai

Membranes 2022, 12(4), 420; https://doi.org/10.3390/membranes12040420 - 14 Apr 2022

Cited by 4 | Viewed by 1725

Abstract

Pharmaceuticals and personal care products have raised significant concerns because of their extensive use, presence in aquatic environments, and potential impacts on wildlife and humans. Carbamazepine was the most frequently detected pharmaceutical residue among pharmaceuticals and personal care products. Nevertheless, the low removal [...] Read more.

Pharmaceuticals and personal care products have raised significant concerns because of their extensive use, presence in aquatic environments, and potential impacts on wildlife and humans. Carbamazepine was the most frequently detected pharmaceutical residue among pharmaceuticals and personal care products. Nevertheless, the low removal efficiency of carbamazepine by conventional wastewater treatment plants was due to resistance to biodegradation at low concentrations. A membrane bioreactor (MBR) has recently attracted attention as a new separation process for wastewater treatment in cities and industries because of its effectiveness in separating pollutants and its tolerance to high or shock loadings. In the current research, the main and interaction effects of three operating parameters, including hydraulic retention time (12–24 h), dissolved oxygen (1.5–5.5 mg/L), and sludge retention time (5–15 days), on removing carbamazepine, chemical oxygen demand, ammonia nitrogen, and phosphorus using ceramic membranes was investigated by applying a two-level full-factorial design analysis. Optimum dissolved oxygen, hydraulic retention time, and sludge retention time were 1.7 mg/L, 24 h, and 5 days, respectively. The research results showed the applicability of the MBR to wastewater treatment with a high carbamazepine loading rate and the removal of nutrients. Full article

(This article belongs to the Special Issue Membrane Applications in Biological Remediation and Purification of Biologics)

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14 pages, 2104 KiB

Open AccessArticle

Elucidating the Water and Methanol Dynamics in Sulfonated Polyether Ether Ketone Nanocomposite Membranes Bearing Layered Double Hydroxides

by Ernestino Lufrano, Isabella Nicotera, Apostolos Enotiadis, Muhammad Habib Ur Rehman and Cataldo Simari

Membranes 2022, 12(4), 419; https://doi.org/10.3390/membranes12040419 - 13 Apr 2022

Cited by 3 | Viewed by 1585

Abstract

Conventional Nafion membranes demonstrate a strong affinity for methanol, resulting in a high fuel crossover, poor mechanical stability, and thus poor performance in direct methanol fuel cells (DMFCs). This study involves the synthesis and physiochemical characterization of an alternative polymer electrolyte membrane for [...] Read more.

Conventional Nafion membranes demonstrate a strong affinity for methanol, resulting in a high fuel crossover, poor mechanical stability, and thus poor performance in direct methanol fuel cells (DMFCs). This study involves the synthesis and physiochemical characterization of an alternative polymer electrolyte membrane for DMFCs based on sulfonated poly(ether ether ketone) and a layered double hydroxide (LDH) material. Nanocomposite membranes (sPL), with filler loading ranging between 1 wt% and 5 wt%, were prepared by simple solution intercalation and characterized by XRD, DMA, swelling tests, and EIS. For the first time, water and methanol mobility inside the hydrophilic channels of sPEEK-LDH membranes were characterized by NMR techniques. The introduction of LDH nanoplatelets improved the dimensional stability while having a detrimental effect on methanol mobility, with its self-diffusion coefficient almost two orders of magnitude lower than that of water. It is worth noting that anionic lamellae are directly involved in the proton transport mechanism, thus enabling the formation of highly interconnected paths for proton conduction. In this regard, sPL₃ yielded a proton conductivity of 110 mS cm⁻¹ at 120 °C and 90% RH, almost attaining the performance of the Nafion benchmark. The nanocomposite membrane also showed an excellent oxidative stability (over more than 24 h) during Fenton’s test at 80 °C. These preliminary results demonstrate that an sPL₃ nanocomposite can be potentially and successfully applied in DMFCs. Full article

(This article belongs to the Special Issue Nanotechnology and Hybrid Membranes)

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20 pages, 2106 KiB

Open AccessArticle

Comparison between Thermophilic and Mesophilic Membrane-Aerated Biofilm Reactors—A Modeling Study

by Duowei Lu, Hao Bai and Baoqiang Liao

Membranes 2022, 12(4), 418; https://doi.org/10.3390/membranes12040418 - 12 Apr 2022

Cited by 4 | Viewed by 1747

Abstract

The concept of thermophilic membrane-aerated biofilm reactor (ThMABR) is studied by modeling. This concept combines the advantages and overcomes the disadvantages of conventional MABR and thermophilic aerobic biological treatment and has great potential to develop a new type of ultra-compact, highly efficient bioreactor [...] Read more.

The concept of thermophilic membrane-aerated biofilm reactor (ThMABR) is studied by modeling. This concept combines the advantages and overcomes the disadvantages of conventional MABR and thermophilic aerobic biological treatment and has great potential to develop a new type of ultra-compact, highly efficient bioreactor for high-strength wastewater and waste gas treatments. Mathematical modeling was conducted to investigate the impact of temperature (mesophilic vs. thermophilic) and oxygen partial pressure on oxygen and substrate concentration profiles, membrane–biofilm interfacial oxygen concentration, oxygen penetration distance, and oxygen and substrate fluxes into biofilms. The general trend of oxygen transfer and substrate flux into biofilm between ThAnMBR and MMABR was verified by the experimental results in the literature. The results from modeling studies indicate that the ThMABR has significant advantages over the conventional mesophilic MABR in terms of improved oxygen and pollutant flux into biofilms and biodegradation rates, and an optimal biofilm thickness exists for maximum oxygen and substrate fluxes into the biofilm. Full article

(This article belongs to the Special Issue Advanced Membrane Technologies for Wastewater Treatment and Recycling)

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19 pages, 6559 KiB

Open AccessArticle

The Intrinsic Parameters of the Polyamide Nanofilm in Thin-Film Composite Reverse Osmosis (TFC-RO) Membranes: The Impact of Monomer Concentration

by Mengling Zhang, Xiangyang Hu, Lei Peng, Shilin Zhou, Yong Zhou, Shijie Xie, Xiaoxiao Song and Congjie Gao

Membranes 2022, 12(4), 417; https://doi.org/10.3390/membranes12040417 - 11 Apr 2022

Cited by 7 | Viewed by 2340

Abstract

The realistic resistance zone of water and salt molecules to transport across a TFC-RO membrane is the topmost polyamide nanofilm. The existence of hollow voids in the fully aromatic polyamide (PA) film gives its surface ridge-and-valley morphologies, which confuses the comprehensions of the [...] Read more.

The realistic resistance zone of water and salt molecules to transport across a TFC-RO membrane is the topmost polyamide nanofilm. The existence of hollow voids in the fully aromatic polyamide (PA) film gives its surface ridge-and-valley morphologies, which confuses the comprehensions of the definition of the PA thickness. The hollow voids, however, neither participate in salt–water separation nor hinder water penetrating. In this paper, the influence of intrinsic thickness (single wall thickness) of the PA layer on water permeability was studied by adjusting the concentration of reacting monomers. It confirms that the true permeation resistance of water molecules originates from the intrinsic thickness portion of the membrane. The experimental results show that the water permeability constant decreases from 3.15 ± 0.02 to 2.74 ± 0.10 L·m⁻²·h⁻¹·bar⁻¹ when the intrinsic thickness of the membrane increases by 9 nm. The defects on the film surface generate when the higher concentration of MPD is matched with the relatively low concentration of TMC. In addition, the role of MPD and TMC in the micro-structure of the PA membrane was discussed, which may provide a new way for the preparation of high permeability and high selectivity composite reverse osmosis membranes. Full article

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

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39 pages, 11193 KiB

Open AccessReview

Polymer Electrolytes for Lithium-Ion Batteries Studied by NMR Techniques

by Vitaly I. Volkov, Olga V. Yarmolenko, Alexander V. Chernyak, Nikita A. Slesarenko, Irina A. Avilova, Guzaliya R. Baymuratova and Alena V. Yudina

Membranes 2022, 12(4), 416; https://doi.org/10.3390/membranes12040416 - 11 Apr 2022

Cited by 16 | Viewed by 4051

Abstract

This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion [...] Read more.

This review is devoted to different types of novel polymer electrolytes for lithium power sources developed during the last decade. In the first part, the compositions and conductivity of various polymer electrolytes are considered. The second part contains NMR applications to the ion transport mechanism. Polymer electrolytes prevail over liquid electrolytes because of their exploitation safety and wider working temperature ranges. The gel electrolytes are mainly attractive. The systems based on polyethylene oxide, poly(vinylidene fluoride-co-hexafluoropropylene), poly(ethylene glycol) diacrylate, etc., modified by nanoparticle (TiO₂, SiO₂, etc.) additives and ionic liquids are considered in detail. NMR techniques such as high-resolution NMR, solid-state NMR, magic angle spinning (MAS) NMR, NMR relaxation, and pulsed-field gradient NMR applications are discussed. ¹H, ⁷Li, and ¹⁹F NMR methods applied to polymer electrolytes are considered. Primary attention is given to the revelation of the ion transport mechanism. A nanochannel structure, compositions of ion complexes, and mobilities of cations and anions studied by NMR, quantum-chemical, and ionic conductivity methods are discussed. Full article

(This article belongs to the Special Issue Ionic and Molecular Transport in Polymeric Electrolytes and Biological Systems Studied by NMR)

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20 pages, 5033 KiB

Open AccessEditor’s ChoiceReview

Complementary Powerful Techniques for Investigating the Interactions of Proteins with Porous TiO₂ and Its Hybrid Materials: A Tutorial Review

by Yihui Dong, Weifeng Lin, Aatto Laaksonen and Xiaoyan Ji

Membranes 2022, 12(4), 415; https://doi.org/10.3390/membranes12040415 - 11 Apr 2022

Viewed by 3116

Abstract

Understanding the adsorption and interaction between porous materials and protein is of great importance in biomedical and interface sciences. Among the studied porous materials, TiO₂ and its hybrid materials, featuring distinct, well-defined pore sizes, structural stability and excellent biocompatibility, are widely used. [...] Read more.

Understanding the adsorption and interaction between porous materials and protein is of great importance in biomedical and interface sciences. Among the studied porous materials, TiO₂ and its hybrid materials, featuring distinct, well-defined pore sizes, structural stability and excellent biocompatibility, are widely used. In this review, the use of four powerful, synergetic and complementary techniques to study protein-TiO_2-based porous materials interactions at different scales is summarized, including high-performance liquid chromatography (HPLC), atomic force microscopy (AFM), surface-enhanced Raman scattering (SERS), and Molecular Dynamics (MD) simulations. We expect that this review could be helpful in optimizing the commonly used techniques to characterize the interfacial behavior of protein on porous TiO₂ materials in different applications. Full article

(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes)

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13 pages, 5537 KiB

Open AccessArticle

Controlling Air Bubble Formation Using Hydrophilic Microfiltration Diffuser for C. vulgaris Cultivation

by Siti Nur Alwani Shafie, Wong Yoong Shen, Jc Jcy Jaymon, Nik Abdul Hadi Md Nordin, Abdelslam Elsir Elsiddig Mohamednour, Muhammad Roil Bilad, Lam Man Kee, Takeshi Matsuura, Mohd Hafiz Dzarfan Othman, Juhana Jaafar and Ahmad Fauzi Ismail

Membranes 2022, 12(4), 414; https://doi.org/10.3390/membranes12040414 - 11 Apr 2022

Cited by 4 | Viewed by 2998

Abstract

In this project, a commercial polytetrafluoroethylene (PTFE) membrane was coated with a thin layer of polyether block amide (PEBAX) via vacuum filtration to improve hydrophilicity and to study the bubble formation. Two parameters, namely PEBAX concentration (of 0–1.5 wt%) and air flow rate [...] Read more.

In this project, a commercial polytetrafluoroethylene (PTFE) membrane was coated with a thin layer of polyether block amide (PEBAX) via vacuum filtration to improve hydrophilicity and to study the bubble formation. Two parameters, namely PEBAX concentration (of 0–1.5 wt%) and air flow rate (of 0.1–50 mL/s), were varied and their effects on the bubble size formation were investigated. The results show that the PEBAX coating reduced the minimum membrane pore size from 0.46 μm without coating (hereafter called PEBAX0) to 0.25 μm for the membrane coated with 1.5wt% of PEBAX (hereafter called PEBAX1.5). The presence of polar functional groups (N-H and C=O) in PEBAX greatly improved the membrane hydrophilicity from 118° for PEBAX0 to 43.66° for PEBAX1.5. At an air flow rate of 43 mL/s, the equivalent bubble diameter size decreased from 2.71 ± 0.14 cm for PEBAX0 to 1.51 ± 0.02 cm for PEBAX1.5. At the same air flow rate, the frequency of bubble formation increased six times while the effective gas–liquid contact area increased from 47.96 cm²/s to 85.6 cm²/s. The improved growth of C. vulgaris from 0.6 g/L to 1.3 g/L for PEBAX1.5 also shows the potential of the PEBAX surface coating porous membrane as an air sparger. Full article

(This article belongs to the Special Issue Special Issue in Honor of Professor Ahmad Fauzi Ismail)

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19 pages, 4138 KiB

Open AccessArticle

One-Step Fabrication of Novel Polyethersulfone-Based Composite Electrospun Nanofiber Membranes for Food Industry Wastewater Treatment

by Md. Nahid Pervez, Md Eman Talukder, Monira Rahman Mishu, Antonio Buonerba, Pasquale Del Gaudio, George K Stylios, Shadi W. Hasan, Yaping Zhao, Yingjie Cai, Alberto Figoli, Tiziano Zarra, Vincenzo Belgiorno, Hongchen Song and Vincenzo Naddeo

Membranes 2022, 12(4), 413; https://doi.org/10.3390/membranes12040413 - 11 Apr 2022

Cited by 24 | Viewed by 3000

Abstract

Using an environmentally friendly approach for eliminating methylene blue from an aqueous solution, the authors developed a unique electrospun nanofiber membrane made of a combination of polyethersulfone and hydroxypropyl cellulose (PES/HPC). SEM results confirmed the formation of a uniformly sized nanofiber membrane with [...] Read more.

Using an environmentally friendly approach for eliminating methylene blue from an aqueous solution, the authors developed a unique electrospun nanofiber membrane made of a combination of polyethersulfone and hydroxypropyl cellulose (PES/HPC). SEM results confirmed the formation of a uniformly sized nanofiber membrane with an ultrathin diameter of 168.5 nm (for PES/HPC) and 261.5 nm (for pristine PES), which can be correlated by observing the absorption peaks in FTIR spectra and their amorphous/crystalline phases in the XRD pattern. Additionally, TGA analysis indicated that the addition of HPC plays a role in modulating their thermal stability. Moreover, the blended nanofiber membrane exhibited better mechanical strength and good hydrophilicity (measured by the contact angle). The highest adsorption capacity was achieved at a neutral pH under room temperature (259.74 mg/g), and the pseudo-second-order model was found to be accurate. In accordance with the Langmuir fitted model and MB adsorption data, it was revealed that the adsorption process occurred in a monolayer form on the membrane surface. The adsorption capacity of the MB was affected by the presence of various concentrations of NaCl (0.1–0.5 M). The satisfactory reusability of the PES/HPC nanofiber membrane was revealed for up to five cycles. According to the mechanism given for the adsorption process, the electrostatic attraction was shown to be the most dominant in increasing the adsorption capacity. Based on these findings, it can be concluded that this unique membrane may be used for wastewater treatment operations with high efficiency and performance. Full article

(This article belongs to the Special Issue Advances in Membrane Science for Sustainable Future)

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12 pages, 3833 KiB

Open AccessArticle

Preparation and Properties of Thin-Film Composite Forward Osmosis Membranes Supported by Cellulose Triacetate Porous Substrate via a Nonsolvent-Thermally Induced Phase Separation Process

by Jian-Chen Han, Xiao-Yan Xing, Jiang Wang and Qing-Yun Wu

Membranes 2022, 12(4), 412; https://doi.org/10.3390/membranes12040412 - 10 Apr 2022

Cited by 8 | Viewed by 2047

Abstract

A porous substrate plays an important role in constructing a thin-film composite forward osmosis (TFC-FO) membrane. To date, the morphology and performance of TFC-FO membranes are greatly limited by porous substrates, which are commonly fabricated by non-solvent induced phase separation (NIPS) or thermally [...] Read more.

A porous substrate plays an important role in constructing a thin-film composite forward osmosis (TFC-FO) membrane. To date, the morphology and performance of TFC-FO membranes are greatly limited by porous substrates, which are commonly fabricated by non-solvent induced phase separation (NIPS) or thermally induced phase separation (TIPS) processes. Herein, a novel TFC-FO membrane has been successfully fabricated by using cellulose triacetate (CTA) porous substrates, which are prepared using a nonsolvent-thermally induced phase separation (N-TIPS) process. The pore structure, permeability, and mechanical properties of CTA porous substrate are carefully investigated via N-TIPS process (CTA_N-TIPS). As compared with those via NIPS and TIPS processes, the CTA_N-TIPS substrate shows a smooth surface and a cross section combining interconnected pores and finger-like macropores, resulting in the largest water flux and best mechanical property. After interfacial polymerization, the obtained TFC-FO membranes are characterized in terms of their morphology and intrinsic transport properties. It is found that the TFC-FO membrane supported by CTA_N-TIPS substrate presents a thin polyamide film full of nodular and worm-like structure, which endows the FO membrane with high water permeability and selectivity. Moreover, the TFC-FO membrane supported by CTA_N-TIPS substrate displays a low internal concentration polarization effect. This work proposes a new insight into preparing TFC-FO membrane with good overall performance. Full article

(This article belongs to the Special Issue Green Membrane Technology)

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3 pages, 183 KiB

Open AccessEditorial

Thin-Film Transistors

by Feng-Tso Chien, Yu-Wei Chang and Jo-Chin Liu

Membranes 2022, 12(4), 411; https://doi.org/10.3390/membranes12040411 - 09 Apr 2022

Viewed by 1642

Abstract

Thin film transistors (TFTs) are key components used in a variety of fields such as solar cell, active-matrix liquid crystal displays (AM-LCDs), pixel switches, peripheral driver circuit and flexible electronics [...] Full article

(This article belongs to the Special Issue Thin-Film Transistors)

15 pages, 769 KiB

Open AccessReview

Characterization and Roles of Membrane Lipids in Fatty Liver Disease

by Morgan Welch, Cassandra Secunda, Nabin Ghimire, Isabel Martinez, Amber Mathus, Urja Patel, Sarayu Bhogoju, Mashael Al-Mutairi, Kisuk Min and Ahmed Lawan

Membranes 2022, 12(4), 410; https://doi.org/10.3390/membranes12040410 - 09 Apr 2022

Cited by 5 | Viewed by 3080

Abstract

Obesity has reached global epidemic proportions and it affects the development of insulin resistance, type 2 diabetes, fatty liver disease and other metabolic diseases. Membrane lipids are important structural and signaling components of the cell membrane. Recent studies highlight their importance in lipid [...] Read more.

Obesity has reached global epidemic proportions and it affects the development of insulin resistance, type 2 diabetes, fatty liver disease and other metabolic diseases. Membrane lipids are important structural and signaling components of the cell membrane. Recent studies highlight their importance in lipid homeostasis and are implicated in the pathogenesis of fatty liver disease. Here, we discuss the numerous membrane lipid species and their metabolites including, phospholipids, sphingolipids and cholesterol, and how dysregulation of their composition and physiology contribute to the development of fatty liver disease. The development of new genetic and pharmacological mouse models has shed light on the role of lipid species on various mechanisms/pathways; these lipids impact many aspects of the pathophysiology of fatty liver disease and could potentially be targeted for the treatment of fatty liver disease. Full article

(This article belongs to the Special Issue Characterization and Roles of Membrane Lipids)

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