Membranes

34 pages, 8351 KiB

Open AccessArticle

Critical Assessment of Membrane Technology Integration in a Coal-Fired Power Plant

by Maytham Alabid, Calin-Cristian Cormos and Cristian Dinca

Membranes 2022, 12(9), 904; https://doi.org/10.3390/membranes12090904 - 19 Sep 2022

Cited by 5 | Viewed by 1779

Despite the many technologies for CO₂ capture (e.g., chemical or physical absorption or adsorption), researchers are looking to develop other technologies that can reduce CAPEX and OPEX costs as well as the energy requirements associated with their integration into thermal power plants. [...] Read more.

Despite the many technologies for CO₂ capture (e.g., chemical or physical absorption or adsorption), researchers are looking to develop other technologies that can reduce CAPEX and OPEX costs as well as the energy requirements associated with their integration into thermal power plants. The aim of this paper was to analyze the technical and economic integration of spiral wound membranes in a coal-fired power plant with an installed capacity of 330 MW (the case of the Rovinari power plant—in Romania). The study modeled energy processes using CHEMCAD version 8.1 software and polymer membranes developed in the CO₂ Hybrid research project. Thus, different configurations such as a single membrane step with and without the use of a vacuum pump and two membrane steps placed in series were analyzed. In all cases, a compressor placed before the membrane system was considered. The use of two serialized stages allows for both high efficiency (minimum 90%) and CO₂ purity of a minimum of 95%. However, the overall plant efficiency decreased from 45.78 to 23.96% and the LCOE increased from 75.6 to 170 €/kWh. The energy consumption required to capture 1 kg of CO₂ is 2.46 MJ_el and 4.52 MJ_th. Full article

(This article belongs to the Special Issue Separation Principles and Applications of Membrane Technology)

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13 pages, 2993 KiB

Open AccessArticle

Carbon-Based Transducers for Solid-Contact Calcium Ion-Selective Electrodes: Mesopore and Nitrogen-Doping Effects

by Yirong Zhang, Yitian Tang, Rongfeng Liang, Lijie Zhong, Jiexian Xu, Huici Lu, Xiaofeng Xu, Tingting Han, Yu Bao, Yingming Ma, Shiyu Gan and Li Niu

Membranes 2022, 12(9), 903; https://doi.org/10.3390/membranes12090903 - 19 Sep 2022

Cited by 5 | Viewed by 2751

Abstract

Solid-contact ion-selective electrodes (SC-ISEs) exhibit great potential in the detection of routine and portable ions which rely on solid-contact (SC) materials for the transduction of ions to electron signals. Carbon-based materials are state-of-the-art SC transducers due to their high electrical double-layer (EDL) capacitance [...] Read more.

Solid-contact ion-selective electrodes (SC-ISEs) exhibit great potential in the detection of routine and portable ions which rely on solid-contact (SC) materials for the transduction of ions to electron signals. Carbon-based materials are state-of-the-art SC transducers due to their high electrical double-layer (EDL) capacitance and hydrophobicity. However, researchers have long searched for ways to enhance the interfacial capacitance in order to improve the potential stability. Herein, three representative carbon-based SC materials including nitrogen-doped mesoporous carbon (NMC), reduced graphene oxide (RGO), and carbon nanotubes (CNT) were compared. The results disclose that the NMC has the highest EDL capacitance owing to its mesopore structure and N-doping while maintaining high hydrophobicity so that no obvious water-layer effect was observed. The Ca²⁺-SC-ISEs based on the SC of NMC exhibited high potential stability compared with RGO and CNT. This work offers a guideline for the development of carbon-material-based SC-ISEs through mesoporous and N-doping engineering to improve the interfacial capacitance. The developed NMC-based solid-contact Ca²⁺-SC-ISE exhibited a Nernstian slope of 26.3 ± 3.1 mV dec⁻¹ ranging from 10 μM to 0.1 M with a detection limit of 3.2 μM. Finally, a practical application using NMC-based SC-ISEs was demonstrated through Ca²⁺ ion analysis in mineral water and soil leaching solutions. Full article

(This article belongs to the Special Issue Sensing Membranes)

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21 pages, 3310 KiB

Open AccessReview

3D Printed and Bioprinted Membranes and Scaffolds for the Periodontal Tissue Regeneration: A Narrative Review

by Irina-Georgeta Sufaru, Georgiana Macovei, Simona Stoleriu, Maria-Alexandra Martu, Ionut Luchian, Diana-Cristala Kappenberg-Nitescu and Sorina Mihaela Solomon

Membranes 2022, 12(9), 902; https://doi.org/10.3390/membranes12090902 - 19 Sep 2022

Cited by 15 | Viewed by 3303

Abstract

Numerous technologies and materials were developed with the aim of repairing and reconstructing the tissue loss in patients with periodontitis. Periodontal guided bone regeneration (GBR) and guided tissue regeneration (GTR) involves the use of a membrane which prevents epithelial cell migration, and helps [...] Read more.

Numerous technologies and materials were developed with the aim of repairing and reconstructing the tissue loss in patients with periodontitis. Periodontal guided bone regeneration (GBR) and guided tissue regeneration (GTR) involves the use of a membrane which prevents epithelial cell migration, and helps to maintain the space, creating a protected area in which tissue regeneration is favored. Over the time, manufacturing procedures of such barrier membranes followed important improvements. Three-dimensional (3D) printing technology has led to major innovations in periodontal regeneration methods, using technologies such as inkjet printing, light-assisted 3D printing or micro-extrusion. Besides the 3D printing of monophasic and multi-phasic scaffolds, bioprinting and tissue engineering have emerged as innovative technologies which can change the way we see GTR and GBR. Full article

(This article belongs to the Special Issue Biocompatible Membranes for Bone Regeneration)

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11 pages, 1738 KiB

Open AccessFeature PaperArticle

Bio-Based Ceramic Membranes for Bacteria Removal from Water

by Pelagie Kamgang-Syapnjeu, Dayirou Njoya, Elie Kamseu, Sebastien Balme, Mikhael Bechelany and Laurence Soussan

Membranes 2022, 12(9), 901; https://doi.org/10.3390/membranes12090901 - 19 Sep 2022

Cited by 1 | Viewed by 1582

Abstract

Bio-based ceramic membranes were elaborated from kaolinite clays, coconut husks and eggshells to retain E. coli bacteria present in water intended for human consumption. Their characterization and removal performances are investigated in this work. These bio-ceramic membranes were obtained by heating the formulation [...] Read more.

Bio-based ceramic membranes were elaborated from kaolinite clays, coconut husks and eggshells to retain E. coli bacteria present in water intended for human consumption. Their characterization and removal performances are investigated in this work. These bio-ceramic membranes were obtained by heating the formulation containing 75% clay, 15% coconut husk and 10% eggshell at 900 °C or 1000 °C, at different temperature rates, to give S1, S2 and S3 materials. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), mercury porosimetry and scanning electron microscopy (SEM) were used to characterize these membranes. Water flux density, bacterial removal and biofouling were also assessed. Water flux density was shown to depend on material porosity. Bacteria retention was 90% (with 1 log-removal) for S1, 80% (with 0.7 log-removal) for S2 and 100% (with 3.3 log-removal) for S3. Membranes S1 and S2 presented reversible biofouling, while no fouling was evidenced for S3 in the tested conditions. This work shows that the best bio-ceramic membrane in terms of bacterial removal and flux density was S3. Its water flux density was 2123 ± 72 L/h/m² at an initial pressure of 0.2 bar. This material is particularly interesting because its production protocol is quite simple, fast and without the addition of chemical additives. Moreover, it can be used to efficiently remove bacteria from drinking water. Full article

(This article belongs to the Special Issue Ceramic Membranes for Wastewater and Water Reuse)

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14 pages, 4253 KiB

Open AccessArticle

Experimental Proof of a Transformation Product Trap Effect with a Membrane Photocatalytic Process for VOC Removal

by Fabien Gérardin, Julien Simard and Éric Favre

Membranes 2022, 12(9), 900; https://doi.org/10.3390/membranes12090900 - 19 Sep 2022

Viewed by 1565

Abstract

The decomposition of volatile organic compounds by photocatalytic oxidation (PCO) has been widely studied. However, the technological development of this oxidative technique has to address how to handle the formation of transformation products. The work presented here investigates the original combination of a [...] Read more.

The decomposition of volatile organic compounds by photocatalytic oxidation (PCO) has been widely studied. However, the technological development of this oxidative technique has to address how to handle the formation of transformation products. The work presented here investigates the original combination of a dense membrane separation process and PCO to intensify the trapping and reduction of PCO transformation products. Specific monitoring of toluene PCO transformation products, such as benzene and formaldehyde, in the outflow of both permeate and retentate compartments was proposed. The influence of operating parameters on the process, i.e., light intensity, pressure, membrane type, and catalyst mass, was also studied. The results reveal that membrane separation-PCO hybridization is particularly effective for reducing the presence of benzene and formaldehyde in the effluent treated. The benzene concentration in the outflow of the hybrid module can be reduced by a factor of 120 compared to that observed during the PCO of toluene alone. Full article

(This article belongs to the Section Membrane Applications)

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13 pages, 2761 KiB

Open AccessArticle

Optimization of Evaporation and Condensation Architectures for Solar-Driven Interfacial Evaporation Desalination

by Cheng Pan, Yawei Yang, Mingze Xie, Qingyuan Deng, Xiang Cheng, Xianlei Wang, Shihan Zhao, Yumeng Wei and Wenxiu Que

Membranes 2022, 12(9), 899; https://doi.org/10.3390/membranes12090899 - 18 Sep 2022

Cited by 4 | Viewed by 2227

Abstract

Solar-driven interfacial evaporation is an ideal technology for seawater desalination, and the corresponding system is mainly composed of a solar evaporator and a condensing collector. The traditional scheme focuses on the evaporation efficiency of the evaporator. Still, it ignores the influence of condensing [...] Read more.

Solar-driven interfacial evaporation is an ideal technology for seawater desalination, and the corresponding system is mainly composed of a solar evaporator and a condensing collector. The traditional scheme focuses on the evaporation efficiency of the evaporator. Still, it ignores the influence of condensing collection scheme on the overall efficiency, which is one of the obstacles to the practical use of solar seawater desalination. Here, we reported a new solar-driven interfacial evaporation seawater desalination system by studying the influence of the condensation architecture, i.e., vapor flow by a fan and an air pump, sidewall material, transparent cover shape and material, evaporation level, and transparent cover heating, on the apparent collection efficiency of the system. The apparent collection efficiency was up to over 90% after optimization. This study is expected to promote the practical application of solar evaporation desalination technology. Full article

(This article belongs to the Special Issue Fabrication, Characterization and Application of Organic/Inorganic Film Membranes and Advanced Materials (Volume II))

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14 pages, 5236 KiB

Open AccessArticle

Study on Static Characteristics of Aerostatic Bearing Based on Porous SiC Ceramic Membranes

by Xin Xiao, Jianzhou Du, Yu Zhang, Jingyi Yan, Yunping Li, Kongjun Zhu and Luming Wang

Membranes 2022, 12(9), 898; https://doi.org/10.3390/membranes12090898 - 17 Sep 2022

Cited by 2 | Viewed by 1735

Abstract

The porous aerostatic bearing is a new supporting structure that is widely used in precision and ultraprecision engineering and the aerospace and other fields. The aerostatic bearing has a good bearing capacity and static stiffness. In this work, the numerical and experimental research [...] Read more.

The porous aerostatic bearing is a new supporting structure that is widely used in precision and ultraprecision engineering and the aerospace and other fields. The aerostatic bearing has a good bearing capacity and static stiffness. In this work, the numerical and experimental research on the static characteristics of an aerostatic bearing based on a porous SiC ceramic membrane is presented. The porous ceramic membrane prepared by reactive sintering, with a porosity of 25.8% and a pore size of 20.55 μm, was used as the restrictor to fabricate the aerostatic bearing. It was found that the ceramics have good permeability, and the permeability coefficient reached 2.78 × 10⁻¹³ m² using permeability-test experiments. The effects of the gas-supply pressure and permeability coefficient on the static characteristics of the aerostatic bearing based on porous ceramics were analyzed using Fluent simulation calculation. When the gas-supply pressure was 0.5 MPa and the gas-film thickness was 6 μm, the static stiffness of the aerostatic bearing reached a maximum of 20.9 N/μm, while the bearing capacity was 632.5 N. The numerical results of the static characteristics of the aerostatic bearing are highly consistent with the experimental results, which verifies the accuracy of the Fluent simulation, and provides convenience for studying the static characteristics of aerostatic bearings. Full article

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12 pages, 1705 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Energy and Nutrients from Apple Waste Using Anaerobic Digestion and Membrane Technology

by Isabel González-García, Berta Riaño, Beatriz Molinuevo-Salces and María Cruz García-González

Membranes 2022, 12(9), 897; https://doi.org/10.3390/membranes12090897 - 17 Sep 2022

Cited by 1 | Viewed by 1567

Abstract

The worldwide increment of food waste requires innovative management solutions, aligned with sustainability, energy, and food security. Anaerobic digestion (AD), followed by nutrient recovery, may be considered an interesting approach. This study proposed a co-digestion of apple pomace (AP) with swine manure (SM) [...] Read more.

The worldwide increment of food waste requires innovative management solutions, aligned with sustainability, energy, and food security. Anaerobic digestion (AD), followed by nutrient recovery, may be considered an interesting approach. This study proposed a co-digestion of apple pomace (AP) with swine manure (SM) to study the effect of different proportions of AP (0, 7.5, 15, and 30%, on a volatile solids (VS) basis) on the methane production and the stability of the process. Subsequently, the gas-permeable membrane (GPM) technology was applied to recover nitrogen (N) as ammonium sulfate (bio-based fertilizer) from the digestates produced after the AD of 7.5% of AP and SM, and SM alone. The results showed that the co-digestion of 7.5% and 15% of AP with SM presented a methane production similar to the AD of SM alone (with 412.3 ± 62.6, 381.8 ± 134.1, and 421.7 ± 153.6 mL g VS⁻¹ day⁻¹, respectively). The later application of the GPM technology on the resulting digestates, with SM alone and with 7.5% of AP with SM, showed total ammoniacal N recovery rates of 33 and 25.8 g N m⁻² d⁻¹, respectively. Therefore, the AP valorization through the AD process, followed by N recovery from the digestate, could be a good management strategy. Full article

(This article belongs to the Special Issue Novel Membranes for Molecular Separations)

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7 pages, 1674 KiB

Open AccessCommunication

The Properties of Intermediate-Temperature Solid Oxide Fuel Cells with Thin Film Gadolinium-Doped Ceria Electrolyte

by Andrey Solovyev, Anna Shipilova, Egor Smolyanskiy, Sergey Rabotkin and Vyacheslav Semenov

Membranes 2022, 12(9), 896; https://doi.org/10.3390/membranes12090896 - 17 Sep 2022

Cited by 9 | Viewed by 1786

Abstract

Mixed ionic-electronic conducting materials are not used as a single-layer electrolyte of solid oxide fuel cells (SOFCs) at relatively high operating temperatures of ~800 °C. This is because of a significant decrease in the open-circuit voltage (OCV) and, consequently, the SOFC power density. [...] Read more.

Mixed ionic-electronic conducting materials are not used as a single-layer electrolyte of solid oxide fuel cells (SOFCs) at relatively high operating temperatures of ~800 °C. This is because of a significant decrease in the open-circuit voltage (OCV) and, consequently, the SOFC power density. The paper presents a comparative analysis of the anode-supported SOFC properties obtained within the temperature range of 600 to 800 °C with yttria-stabilized zirconia (YSZ) electrolyte and gadolinium-doped ceria (GDC) electrolyte thin films. Electrolyte layers that are 3 µm thick are obtained by magnetron sputtering. It is shown that at 800 °C, the SOFC with the GDC electrolyte thin film provides an OCV over 0.9 V and power density of 2 W/cm². The latter is comparable to the power density of SOFCs with the YSZ electrolyte, which is a purely ionic conductor. The GDC electrolyte manifests the high performance, despite the SOFC power density loss induced by electronic conductivity of the former, which, in turn, is compensated by its other positive properties. Full article

(This article belongs to the Section Membrane Applications)

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16 pages, 641 KiB

Open AccessReview

Gradual Drug Release Membranes and Films Used for the Treatment of Periodontal Disease

by Nausica Petrescu, Bogdan Crisan, Ovidiu Aghiorghiesei, Codruta Sarosi, Ioana Codruta Mirica, Ondine Lucaciu, Simina Angela Lăcrimioara Iușan, Noemi Dirzu and Dragos Apostu

Membranes 2022, 12(9), 895; https://doi.org/10.3390/membranes12090895 - 17 Sep 2022

Cited by 3 | Viewed by 2060

Abstract

Periodontitis is an inflammatory disease that, if not treated, can cause a lot of harm to the oral cavity, to the patients’ quality of life, and to the entire community. There is no predictable standardized treatment for periodontitis, but there have been many [...] Read more.

Periodontitis is an inflammatory disease that, if not treated, can cause a lot of harm to the oral cavity, to the patients’ quality of life, and to the entire community. There is no predictable standardized treatment for periodontitis, but there have been many attempts, using antibiotics, tissue regeneration techniques, dental scaling, or root planning. Due to the limits of the above-mentioned treatment, the future seems to be local drug delivery systems, which could gradually release antibiotics and tissue regeneration inducers at the same time. Local gradual release of antibiotics proved to be more efficient than systemic administration. In this review, we have made a literature search to identify the articles related to this topic and to find out which carriers have been tested for drug release as an adjuvant in the treatment of periodontitis. Considering the inclusion and exclusion criteria, 12 articles were chosen to be part of this review. The selected articles indicated that the drug-releasing carriers in periodontitis treatment were membranes and films fabricated from different types of materials and through various methods. Some of the drugs released by the films and membranes in the selected articles include doxycycline, tetracycline, metronidazole, levofloxacin, and minocycline, all used with good outcome regarding their bactericide effect; BMP-2, Zinc–hydroxyapatite nanoparticles with regenerative effect. The conclusion derived from the selected studies was that gradual drug release in the periodontal pockets is a promising strategy as an adjuvant for the treatment of periodontal disease. Full article

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20 pages, 2792 KiB

Open AccessArticle

Analysis of Calcium Sulfate Scaling Phenomena on Reverse Osmosis Membranes by Scaling-Based Flux Model

by Fumio Yokoyama, Mitsutoshi Nakajima and Sosaku Ichikawa

Membranes 2022, 12(9), 894; https://doi.org/10.3390/membranes12090894 - 17 Sep 2022

Cited by 3 | Viewed by 1568

Abstract

In this study, the behavior of permeate flux decline due to scale precipitation of calcium sulfate on reverse osmosis membranes was investigated. The proposed scaling-based flux model is able to explain that permeate fluxes attributed to three mechanisms of scale precipitation—cake formation, surface [...] Read more.

In this study, the behavior of permeate flux decline due to scale precipitation of calcium sulfate on reverse osmosis membranes was investigated. The proposed scaling-based flux model is able to explain that permeate fluxes attributed to three mechanisms of scale precipitation—cake formation, surface blockage, and mixed crystallization—converge to the same newly defined scaling-based critical flux. In addition, a scaling index is defined, which determines whether scale precipitates on the membrane. The experimental results were analyzed based on this index. The mass-transfer coefficients of flat membrane cells used in the experiments were measured and, although the coefficients differed, they could be summarized in the same form as the Leveque equation. Considering the results of the scale precipitation experiments, where the operating conditions of pressure, solute concentration, temperature, and Reynolds number were varied, the convergent values of the permeate fluxes are explained by the scaling-based critical fluxes and the scale precipitation zones by the scaling indexes. Full article

(This article belongs to the Special Issue Pressure-Driven Membrane Processes Treating Industrial Water and Wastewater for Better ESG Performance)

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14 pages, 566 KiB

Open AccessReview

Mitochondrial Fission and Fusion: Molecular Mechanisms, Biological Functions, and Related Disorders

by Mode Al Ojaimi, Azza Salah and Ayman W. El-Hattab

Membranes 2022, 12(9), 893; https://doi.org/10.3390/membranes12090893 - 16 Sep 2022

Cited by 25 | Viewed by 3209

Abstract

Mitochondria are dynamic organelles that undergo fusion and fission. These active processes occur continuously and simultaneously and are mediated by nuclear-DNA-encoded proteins that act on mitochondrial membranes. The balance between fusion and fission determines the mitochondrial morphology and adapts it to the metabolic [...] Read more.

Mitochondria are dynamic organelles that undergo fusion and fission. These active processes occur continuously and simultaneously and are mediated by nuclear-DNA-encoded proteins that act on mitochondrial membranes. The balance between fusion and fission determines the mitochondrial morphology and adapts it to the metabolic needs of the cells. Therefore, these two processes are crucial to optimize mitochondrial function and its bioenergetics abilities. Defects in mitochondrial proteins involved in fission and fusion due to pathogenic variants in the genes encoding them result in disruption of the equilibrium between fission and fusion, leading to a group of mitochondrial diseases termed disorders of mitochondrial dynamics. In this review, the molecular mechanisms and biological functions of mitochondrial fusion and fission are first discussed. Then, mitochondrial disorders caused by defects in fission and fusion are summarized, including disorders related to MFN2, MSTO1, OPA1, YME1L1, FBXL4, DNM1L, and MFF genes. Full article

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14 pages, 1499 KiB

Open AccessArticle

The Influence of Forward Osmosis Module Configuration on Nutrients Removal and Microalgae Harvesting in Osmotic Photobioreactor

by Mathieu Larronde-Larretche and Xue Jin

Membranes 2022, 12(9), 892; https://doi.org/10.3390/membranes12090892 - 16 Sep 2022

Cited by 3 | Viewed by 1507

Abstract

Microalgae have attracted great interest recently due to their potential for nutrients removal from wastewater, renewable biodiesel production and bioactive compounds extraction. However, one major challenge in microalgal bioremediation and the algal biofuel process is the high energy cost of separating microalgae from [...] Read more.

Microalgae have attracted great interest recently due to their potential for nutrients removal from wastewater, renewable biodiesel production and bioactive compounds extraction. However, one major challenge in microalgal bioremediation and the algal biofuel process is the high energy cost of separating microalgae from water. Our previous studies demonstrated that forward osmosis (FO) is a promising technology for microalgae harvesting and dewatering due to its low energy consumption and easy fouling control. In the present study, two FO module configurations (side-stream and submerged) were integrated with microalgae (C. vulgaris) photobioreactor (PBR) in order to evaluate the system performance, including nutrients removal, algae harvesting efficiency and membrane fouling. After 7 days of operation, both systems showed effective nutrients removal. A total of 92.9%, 100% and 98.7% of PO₄-P, NH₃-N and TN were removed in the PBR integrated with the submerged FO module, and 82%, 96% and 94.8% of PO₄-P, NH₃-N and TN were removed in the PBR integrated with the side-stream FO module. The better nutrients removal efficiency is attributed to the greater algae biomass in the submerged FO-PBR where in situ biomass dewatering was conducted. The side-stream FO module showed more severe permeate flux loss and biomass loss (less dewatering efficiency) due to algae deposition onto the membrane. This is likely caused by the higher initial water flux associated with the side-stream FO configuration, resulting in more foulants being transported to the membrane surface. However, the side-stream FO module showed better fouling mitigation by simple hydraulic flushing than the submerged FO module, which is not convenient for conducting cleaning without interrupting the PBR operation. Taken together, our results suggest that side-stream FO configuration may provide a viable way to integrate with PBR for a microalgae-based treatment. The present work provides novel insights into the efficient operation of a FO-PBR for more sustainable wastewater treatment and effective microalgae harvesting. Full article

(This article belongs to the Special Issue Emerging Membrane Technologies for Environmental Sustainability: Fundamentals and Applications)

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19 pages, 6665 KiB

Open AccessArticle

Simulation Study of the Effect of Antimicrobial Peptide Associations on the Mechanism of Action with Bacterial and Eukaryotic Membranes

by Matko Maleš and Larisa Zoranić

Membranes 2022, 12(9), 891; https://doi.org/10.3390/membranes12090891 - 16 Sep 2022

Cited by 3 | Viewed by 3013

Abstract

Antimicrobial peptides (AMPs) can be directed to specific membranes based on differences in lipid composition. In this study, we performed atomistic and coarse-grained simulations of different numbers of the designed AMP adepantin-1 with a eukaryotic membrane, cytoplasmic Gram-positive and Gram-negative membranes, and an [...] Read more.

Antimicrobial peptides (AMPs) can be directed to specific membranes based on differences in lipid composition. In this study, we performed atomistic and coarse-grained simulations of different numbers of the designed AMP adepantin-1 with a eukaryotic membrane, cytoplasmic Gram-positive and Gram-negative membranes, and an outer Gram-negative membrane. At the core of adepantin-1’s behavior is its amphipathic α-helical structure, which was implemented in its design. The amphipathic structure promotes rapid self-association of peptide in water or upon binding to bacterial membranes. Aggregates initially make contact with the membrane via positively charged residues, but with insertion, the hydrophobic residues are exposed to the membrane’s hydrophobic core. This adaptation alters the aggregate’s stability, causing the peptides to diffuse in the polar region of the membrane, mostly remaining as a single peptide or pairing up to form an antiparallel dimer. Thus, the aggregate’s proposed role is to aid in positioning the peptide into a favorable conformation for insertion. Simulations revealed the molecular basics of adepantin-1 binding to various membranes, and highlighted peptide aggregation as an important factor. These findings contribute to the development of novel anti-infective agents to combat the rapidly growing problem of bacterial resistance to antibiotics. Full article

(This article belongs to the Special Issue Artificial Models of Biological Membranes)

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11 pages, 2028 KiB

Open AccessArticle

Involvement of Multidrug Resistance Modulators in the Regulation of the Mitochondrial Permeability Transition Pore

by Tatiana Fedotcheva, Nikolai Shimanovsky and Nadezhda Fedotcheva

Membranes 2022, 12(9), 890; https://doi.org/10.3390/membranes12090890 - 16 Sep 2022

Cited by 4 | Viewed by 1422

Abstract

The permeability transition pore in mitochondria (MPTP) and the ATP-binding cassette transporters (АВС transporters) in cell membranes provide the efflux of low-molecular compounds across mitochondrial and cell membranes, respectively. The inhibition of ABC transporters, especially of those related to multi drug resistance (MDR) [...] Read more.

The permeability transition pore in mitochondria (MPTP) and the ATP-binding cassette transporters (АВС transporters) in cell membranes provide the efflux of low-molecular compounds across mitochondrial and cell membranes, respectively. The inhibition of ABC transporters, especially of those related to multi drug resistance (MDR) proteins, is an actively explored approach to enhance intracellular drug accumulation and increase thereby the efficiency of anticancer therapy. Although there is evidence showing the simultaneous effect of some inhibitors on both MDR-related proteins and mitochondrial functions, their influence on MPTP has not been previously studied. We examined the participation of verapamil and quinidine, classified now as the first generation of MDR modulators, and avermectin, which has recently been actively studied as an MDR inhibitor, in the regulation of the MPTP opening. In experiments on rat liver mitochondria, we found that quinidine lowered and verapamil increased the threshold concentrations of calcium ions required for MPTP opening, and that they both decreased the rate of calcium-induced swelling of mitochondria. These effects may be associated with the positive charge of the drugs and their aliphatic properties. Avermectin not only decreased the threshold concentration of calcium ions, but also by itself induced the opening of MPTP and the mitochondrial swelling inhibited by ADP and activated by carboxyatractyloside, the substrate and inhibitor of adenine nucleotide translocase (ANT), which suggests the involvement of ANT in the process. Thus, these data indicate an additional opportunity to evaluate the effectiveness of MDR modulators in the context of their influence on the mitochondrial-dependent apoptosis. Full article

(This article belongs to the Special Issue Membrane Permeability and Channels)

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15 pages, 4643 KiB

Open AccessArticle

Synthesis and Characterization of Silica–Tantala Microporous Membranes for Gas Separations Fabricated Using Chemical Vapor Deposition

by Sean-Thomas B. Lundin, Hongsheng Wang and S. Ted Oyama

Membranes 2022, 12(9), 889; https://doi.org/10.3390/membranes12090889 - 16 Sep 2022

Cited by 2 | Viewed by 1586

Abstract

Composite membranes consisting of microporous tantalum-doped silica layers supported on mesoporous alumina substrates were fabricated using chemical vapor deposition (CVD) in both thermal decomposition and counter-flow oxidative deposition modes. Tetraethyl orthosilicate (TEOS) was used as the silica precursor and tantalum (V) ethoxide (TaEO) [...] Read more.

Composite membranes consisting of microporous tantalum-doped silica layers supported on mesoporous alumina substrates were fabricated using chemical vapor deposition (CVD) in both thermal decomposition and counter-flow oxidative deposition modes. Tetraethyl orthosilicate (TEOS) was used as the silica precursor and tantalum (V) ethoxide (TaEO) as the tantalum source. Amounts of TaEO from 0 mol% to 40 mol% were used in the CVD gas mixture and high H₂ permeances above 10⁻⁷ mol m⁻² s⁻¹ Pa⁻¹ were obtained for all conditions. Close examination was made of the H₂/CH₄ and O₂/CH₄ selectivities due to the potential use of these membranes in methane reforming or partial oxidation of methane applications. Increasing deposition temperature correlated with increasing H₂/CH₄ selectivity at the expense of O₂/CH₄ selectivity, suggesting a need to optimize membrane synthesis for a specific selectivity. Measured at 400 °C, the highest H₂/CH₄ selectivity of 530 resulted from thermal CVD at 650 °C, whereas the highest O₂/CH₄ selectivity of 6 resulted from thermal CVD at 600 °C. The analysis of the membranes attempted by elemental analysis, X-ray photoelectron spectroscopy, and X-ray absorption near-edge spectroscopy revealed that Ta was undetectable because of instrumental limitations. However, the physical properties of the membranes indicated that the Ta must have been present at least at dopant levels. It was found that the pore size of the resultant membranes increased from 0.35 nm for pure Si to 0.37 nm for a membrane prepared with 40 mol% Ta. Similarly, an increase in Ta in the feed resulted in an increase in O₂/CH₄ selectivity at the expense of H₂/CH₄ selectivity. Additionally, it resulted in a decrease in hydrothermal stability, with the membranes prepared with higher Ta suffering greater permeance and selectivity declines during 96 h of exposure to 16 mol% H₂O in Ar at 650 °C. Full article

(This article belongs to the Collection Feature Papers in Membrane Engineering and Applications)

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15 pages, 1411 KiB

Open AccessArticle

Behavior of Mebendazole during NF/RO Adsorption and Photolysis

by Bruna Babić, Darko Andrić, Anamarija Farkaš, Dragana Vuk, Danijela Ašperger and Davor Dolar

Membranes 2022, 12(9), 888; https://doi.org/10.3390/membranes12090888 - 15 Sep 2022

Cited by 2 | Viewed by 1327

Abstract

The idea of using drugs from the benzimidazole group as potential antitumor agents is becoming increasingly popular and widespread in research. However, their use as antiparasitics and in cancer treatment will increase their already recorded occurrence in the aquatic environment. In this study, [...] Read more.

The idea of using drugs from the benzimidazole group as potential antitumor agents is becoming increasingly popular and widespread in research. However, their use as antiparasitics and in cancer treatment will increase their already recorded occurrence in the aquatic environment. In this study, the removal of the anthelmintic mebendazole from aqueous solution was investigated using nanofiltration and reverse osmosis membranes, adsorption on granular activated carbon (GAC), and photolytic degradation. The dense NF90 and reverse osmosis XLE membranes showed almost complete removal (>97.7%), while the NF270 membrane showed a large dependence of removal on initial concentration from 41.9% to 96.6%. Adsorption in the column resulted in complete removal of mebendazole at the highest GAC height used (40 cm) from the solution with the lowest concentration (1 mg/L). Photolytic degradation by artificial light for 2 and 12 h resulted in photodegradation of mebendazole in the range of 23.5–61.4%, forming a new degradation or transformation compound with an m/z ratio of 311. Mebendazole is a photosensitive drug whose photodegradation follows first-order kinetics and depends on the drug concentration. Toxicity was studied with Vibrio fischeri before and after photolysis, and showed a decrease in inhibition after 12 h. Full article

(This article belongs to the Special Issue UF/NF/RO Membranes for Wastewater Treatment and Reuse)

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12 pages, 2227 KiB

Open AccessArticle

Fabrication of Loose Nanofiltration Membranes with High Rejection Selectivity between Natural Organic Matter and Salts for Drinking Water Treatment

by Zhihai He, Kunpeng Wang, Yanling Liu, Ting Zhang and Xiaomao Wang

Membranes 2022, 12(9), 887; https://doi.org/10.3390/membranes12090887 - 15 Sep 2022

Cited by 2 | Viewed by 1812

Abstract

Loose nanofiltration (LNF) membranes with a molecular weight cut-off (MWCO) of about 1000 Da and high surface negative charge density have great application potential for drinking water treatment pursuing high rejection selectivity between natural organic matter (NOM) and mineral salts. This study was [...] Read more.

Loose nanofiltration (LNF) membranes with a molecular weight cut-off (MWCO) of about 1000 Da and high surface negative charge density have great application potential for drinking water treatment pursuing high rejection selectivity between natural organic matter (NOM) and mineral salts. This study was conducted to exploit the novel method coupling non-solvent induced phase separation (NIPS) and interfacial polymerization (IP) for the preparation of high-performance LNF membranes. A number of LNF membranes were synthesized by varying the polyethersulfone (PES) and piperazine (PIP) concentrations in the cast solution for the PES support layer preparation. Results showed that these two conditions could greatly affect the membrane water permeance, MWCO and surface charge. One LNF membrane, with a water permeance as high as 23.0 ± 1.8 L/m²/h/bar, when used for the filtration of conventional process-treated natural water, demonstrated a rejection of NOM higher than 70% and a low rejection of mineral salts at about 20%. Both the mineral salts/NOM selectivity and permselectivity were superior to the currently available LNF membranes as far as the authors know. This study demonstrated the great advantage of the NIPS–IP method for the fabrication of LNF membranes, particularly for the advanced treatment of drinking water. Full article

(This article belongs to the Section Membrane Applications)

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15 pages, 4054 KiB

Open AccessArticle

Study on the Shear Behaviour and Fracture Characteristic of Graphene Kirigami Membranes via Molecular Dynamics Simulation

by Yuan Gao, Shuaijie Lu, Weiqiang Chen, Ziyu Zhang and Chen Gong

Membranes 2022, 12(9), 886; https://doi.org/10.3390/membranes12090886 - 14 Sep 2022

Cited by 3 | Viewed by 1728

Abstract

In this study, we aimed to provide systematic and critical research to investigate the shear performance and reveal the corresponding structural response and fracture characteristics of the monolayer GK membrane. The results demonstrate that the kirigami structure significant alters the shear performance of [...] Read more.

In this study, we aimed to provide systematic and critical research to investigate the shear performance and reveal the corresponding structural response and fracture characteristics of the monolayer GK membrane. The results demonstrate that the kirigami structure significant alters the shear performance of graphene-based sheets. Tuning the porosity by controlling the incision size, pore distribution, and incision direction can effectively adjust the shear strength and elastic modulus of GK membranes. The trade-off of the stress and strain of the GK membrane is critical to its shear behaviour. The microstructural damage processes and failure characteristics further reveal that making more carbon atoms on the GK structure sharing the strain energy is the key to reinforcing the shear performance of membranes. Based on this, we found that adding the shear loading in the direction of perpendicular to the incisions on the GK membrane can significantly improve the shear strength and stiffness of the membrane by 26.2–32.1% and 50.2–75.3% compared to applying shear force parallel to GK incisions. This research not only broadens the understanding of shear properties of monolayer GO membrane but also provides more reference on the fracture characteristics of GK membranes for future manufacturing and applications. Full article

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12 pages, 1583 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Technical and Environmental Feasibilities of the Commercial Production of NaOH from Brine by Means of an Integrated EDBM and Evaporation Process

by Marta Herrero-Gonzalez and Raquel Ibañez

Membranes 2022, 12(9), 885; https://doi.org/10.3390/membranes12090885 - 14 Sep 2022

Cited by 4 | Viewed by 1802

Abstract

Electrodialysis with bipolar membranes (EDBMs) is a technology that offers a great potential for the introduction of the principles of a circular economy in the desalination industry, by providing a strategy for the recovery of HCl and NaOH from brine via the process [...] Read more.

Electrodialysis with bipolar membranes (EDBMs) is a technology that offers a great potential for the introduction of the principles of a circular economy in the desalination industry, by providing a strategy for the recovery of HCl and NaOH from brine via the process of seawater reverse osmosis (SWRO). Both chemicals are widely employed in desalination facilities, however NaOH presents a special interest due to its higher requirements and cost. Nevertheless, the standard commercial concentrations that are commonly employed in the facilities cannot be obtained using the state of the art EDBM technology itself. Therefore, the aim and main purpose of this work is to prove the technical and environmental feasibilities of a new approach to produce commercial NaOH (50%wt.) from SWRO brine by means of an integrated process of EDBMs followed by a triple effect evaporation. The global process has been technically evaluated in terms of the specific energy consumption (SEC) (kWh·kg⁻¹ NaOH) and the environmental sustainability performance has been analyzed by its carbon footprint (CF) (kg CO₂-eq.·kg⁻¹ NaOH). The influence of the current density, and the power source in the EDBM stage have been evaluated on a laboratory scale while the influence of the feed stream concentration in the evaporation stage has been obtained through simulations using Aspen Plus. The lowest SEC of the integrated process (SEC_OV), 31.1 kWh·kg⁻¹ NaOH, is obtained when an average current density of 500 A·m⁻², provided by a power supply (grid mix), is applied in the EDBM stage. The environmental burdens of the integrated process have been quantified by achieving reductions in the CF by up to 54.7% when solar photovoltaic energy is employed as the power source for EDBMs, with a value of 5.38 kg CO₂-eq.·kg⁻¹ NaOH. This study presents a great potential for the introduction of the principles of a circular economy in the water industry through the recovery of NaOH from the high salinity waste stream generated in SWRO facilities and opens the possibility of the reuse of NaOH by its self-supply in the desalination plant. Full article

(This article belongs to the Special Issue Advance in Electromembrane Technology)

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13 pages, 3568 KiB

Open AccessFeature PaperArticle

Membrane Separation Processes and Post-Combustion Carbon Capture: State of the Art and Prospects

by Eric Favre

Membranes 2022, 12(9), 884; https://doi.org/10.3390/membranes12090884 - 14 Sep 2022

Cited by 14 | Viewed by 3658

Abstract

Membrane processes have been investigated for carbon capture for more than four decades. Important efforts have been more recently achieved for the development of advanced materials and, to a lesser extent, on process engineering studies. A state-of-the-art analysis is proposed with a critical [...] Read more.

Membrane processes have been investigated for carbon capture for more than four decades. Important efforts have been more recently achieved for the development of advanced materials and, to a lesser extent, on process engineering studies. A state-of-the-art analysis is proposed with a critical comparison to gas absorption technology, which is still considered as the best available technology for this application. The possibilities offered by high-performance membrane materials (zeolites, Carbon Molecular Sieves, Metal Oxide Frameworks, graphenes, facilitated transport membranes, etc.) are discussed in combination to process strategies (multistage design, hybrid processes, energy integration). The future challenges and open questions of membranes for carbon capture are finally proposed. Full article

(This article belongs to the Special Issue Membrane Process Systems and Techniques)

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18 pages, 3600 KiB

Open AccessArticle

Comparison of Artificial Intelligence Control Strategies for a Peristaltically Pumped Low-Pressure Driven Membrane Process

by José-Luis Díez, Vicente Masip-Moret, Asunción Santafé-Moros and José M. Gozálvez-Zafrilla

Membranes 2022, 12(9), 883; https://doi.org/10.3390/membranes12090883 - 13 Sep 2022

Cited by 3 | Viewed by 1374

Abstract

Peristaltic pumping is used in membrane applications where high and sterile sealing is required. However, control is difficult due to the pulsating pump characteristics and the time-varying properties of the system. In this work, three artificial intelligence control strategies (artificial neural networks (ANN), [...] Read more.

Peristaltic pumping is used in membrane applications where high and sterile sealing is required. However, control is difficult due to the pulsating pump characteristics and the time-varying properties of the system. In this work, three artificial intelligence control strategies (artificial neural networks (ANN), fuzzy logic expert systems, and fuzzy-integrated local models) were used to regulate transmembrane pressure and crossflow velocity in a microfiltration system under high fouling conditions. A pilot plant was used to obtain the necessary data to identify the AI models and to test the controllers. Humic acid was employed as a foulant, and cleaning-in-place with NaOH was used to restore the membrane state. Several starting operating points were studied and setpoint changes were performed to study the plant dynamics under different control strategies. The results showed that the control approaches were able to control the membrane system, but significant differences in the dynamics were observed. The ANN control was able to achieve the specifications but showed poor dynamics. Expert control was fast but showed problems in different working areas. Local models required less data than ANN, achieving high accuracy and robustness. Therefore, the technique to be used will depend on the available information and the application dynamics requirements. Full article

(This article belongs to the Special Issue Modeling and Simulation of Industrial and Environmental Processes with Membranes)

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15 pages, 2950 KiB

Open AccessArticle

Direct Purification of Digestate Using Polymeric Ultrafiltration Membranes: Influence of Materials on Filtration Behavior and Fouling Characteristics

by Caide Yue, Yongxing Chen, Wanqin Zhang, Yunhao Zheng, Xuzhao Hu and Bin Shang

Membranes 2022, 12(9), 882; https://doi.org/10.3390/membranes12090882 - 13 Sep 2022

Cited by 2 | Viewed by 1462

Abstract

In-depth exploration of filtration behavior and fouling characteristics of polymeric ultrafiltration (UF) membranes can provide guidance for the selection of materials and the control of membrane fouling during the purification of digestate. In this study, four types of polymeric membranes, (polyethersulfone (PES), polysulfone [...] Read more.

In-depth exploration of filtration behavior and fouling characteristics of polymeric ultrafiltration (UF) membranes can provide guidance for the selection of materials and the control of membrane fouling during the purification of digestate. In this study, four types of polymeric membranes, (polyethersulfone (PES), polysulfone (PS), polyvinylidene fluoride (PVDF), and polyacrylonitrile (PAN)), were employed to filter digestate from swine manure. The results showed that the viscosity of the digestate dropped from 45.0 ± 11.3 mPa·s to 18.0 ± 9.8 mPa·s, with an increase in temperature from 30.0 °C to 45.0 °C. The four membrane fluxes all increased by more than 30%, with the cross flow velocity increasing from 1.0 m s⁻¹ to 2.0 m s⁻¹. During the batch experiments, the flux maintenance abilities of the membranes were in the order: PAN > PS > PVDF > PES. There were no significant differences in the effects of membrane materials on the removal of COD, TN, and TP (p < 0.05). For UV₂₅₄ removal efficiency, PS showed the highest efficiency (68.6%), while PVDF showed the lowest efficiency (63.4%). The major fouling type was irreversible hydraulic fouling, and the main elements of scaling were C, O, S, and Ca. Pseudomonadales were the dominant bacteria in the PS (26.2%) and in the PVDF (51.4%) fouling layers, while Bacteroidales were the dominant bacteria in the PES (26.8%) and in the PAN (14.7%) fouling layers. The flux recovery rates (FRRs) of the cleaning methods can be arranged as follows: NaClO > NaOH > Citric acid ≈ Tap water. After NaClO cleaning, the PVDF membrance showed the highest FRR (73.1%), and the PAN membrane showed the lowest FRR (30.1%). Full article

(This article belongs to the Section Membrane Applications)

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11 pages, 4350 KiB

Open AccessArticle

Thin Film Composite Membranes Based on the Polymer of Intrinsic Microporosity PIM-EA(Me₂)-TB Blended with Matrimid^®5218

by Mariagiulia Longo, Marcello Monteleone, Elisa Esposito, Alessio Fuoco, Elena Tocci, Maria-Chiara Ferrari, Bibiana Comesaña-Gándara, Richard Malpass-Evans, Neil B. McKeown and Johannes C. Jansen

Membranes 2022, 12(9), 881; https://doi.org/10.3390/membranes12090881 - 13 Sep 2022

Cited by 7 | Viewed by 2246

Abstract

In this work, thin film composite (TFC) membranes were fabricated with the selective layer based on a blend of polyimide Matrimid^®5218 and polymer of intrinsic microporosity (PIM) composed of Tröger’s base, TB, and dimethylethanoanthracene units, PIM-EA(Me₂)-TB. The TFCs were [...] Read more.

In this work, thin film composite (TFC) membranes were fabricated with the selective layer based on a blend of polyimide Matrimid^®5218 and polymer of intrinsic microporosity (PIM) composed of Tröger’s base, TB, and dimethylethanoanthracene units, PIM-EA(Me₂)-TB. The TFCs were prepared with different ratios of the two polymers and the effect of the PIM content in the blend of the gas transport properties was studied for pure He, H₂, O₂, N₂, CH₄, and CO₂ using the well-known time lag method. The prepared TFC membranes were further characterized by IR spectroscopy and scanning electron microscopy (SEM). The role of the support properties for the TFC membrane preparation was analysed for four different commercial porous supports (Nanostone Water PV 350, Vladipor Fluoroplast 50, Synder PAN 30 kDa, and Sulzer PAN UF). The Sulzer PAN UF support with a relatively small pore size favoured the formation of a defect-free dense layer. All the TFC membranes supported on Sulzer PAN UF presented a synergistic enhancement in CO₂ permeance, and CO₂/CH₄ and CO₂/N₂ ideal selectivity. The permeance increased about two orders of magnitude with respect to neat Matrimid, up to ca. 100 GPU, the ideal CO₂/CH₄ selectivity increased from approximately 10 to 14, and the CO₂/N₂ selectivity from approximately 20 to 26 compared to the thick dense reference membrane of PIM-EA(Me₂)-TB. The TFC membranes exhibited lower CO₂ permeances than expected on the basis of their thickness—most likely due to enhanced aging of thin films and to the low surface porosity of the support membrane, but a higher selectivity for the gas pairs CO₂/N₂, CO₂/CH₄, O₂/N₂, and H₂/N₂. 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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10 pages, 2212 KiB

Open AccessArticle

Dislodging Dichromate in Mine Slops Applying Flat Supplying Membrane Equipment Containing Carrier N235/7301

by Liang Pei

Membranes 2022, 12(9), 880; https://doi.org/10.3390/membranes12090880 - 12 Sep 2022

Viewed by 1136

Abstract

A novel flat supplying membrane equipment (FSME) with a sodium hydroxide solution and a mixture of N235/7301 and petroleum has been studied for dislodging dichromate (which can be expressed as Cr (VI) or Cr₂O₇²⁻) from simulated mine slops. [...] Read more.

A novel flat supplying membrane equipment (FSME) with a sodium hydroxide solution and a mixture of N235/7301 and petroleum has been studied for dislodging dichromate (which can be expressed as Cr (VI) or Cr₂O₇²⁻) from simulated mine slops. The FSME contained three parts: as a feeding cell, a reacting cell, and a supplying cell. The flat Kynoar membrane was inlaid in the middle of the reacting cell, using the mixed solutions of petroleum and sodium hydroxide, with Tri (octyl decyl) alkyl tertiary amine (N235/7301) as the carrier in the supplying cell and the mine slops with Cr (VI) as the feeding section. The impact parameters of pH and the other ion density in the feeding solutions, the voluminal ratio of petroleum to sodium hydroxide solution and N235/7301 concentration in the supplying solutions were investigated for the obtaining of the optimal technique parameters. It was found that the dislodging rate of Cr (VI) could reach 93.3% in 215 min when the concentration of carrier (N235/7301) was 0.20 mol/L, the voluminal ratio of petroleum and sodium hydroxide in the supplying cell was 1:1, the pH of the feeding section was 4.00, and the Cr (VI) cinit was 3.00 × 10⁻⁴ mol/L. The practicability and steadiness of FSME were gained through the exploration of Cr (VI) adsorption on the membrane surface. Full article

(This article belongs to the Special Issue Membrane Distillation for Wastewater Treatment)

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13 pages, 6545 KiB

Open AccessArticle

Theoretical and Experimental Study of the Effect of Plasma Characteristics on the Mechanical Properties of Ihram Cotton Fabric

by Ahmed Rida Galaly and Nagia Dawood

Membranes 2022, 12(9), 879; https://doi.org/10.3390/membranes12090879 - 12 Sep 2022

Cited by 2 | Viewed by 1252

Abstract

Theoretical and experimental investigations of the radial distribution function of the electron temperature (RDFT), for the abnormal glow region in a low-density plasma fluid and weakly ionized argon gas, are provided. The final proved equation of RDFT agrees with the experimental data for [...] Read more.

Theoretical and experimental investigations of the radial distribution function of the electron temperature (RDFT), for the abnormal glow region in a low-density plasma fluid and weakly ionized argon gas, are provided. The final proved equation of RDFT agrees with the experimental data for different low pressures ranging from 0.2 to 1.2 torr, confirming that the electron temperatures decrease with an increasing product of radial distance (R) and gas pressures (P). A comparison of the two configurations:

R > L and L > R,

for the axial distance (L), from the tip of the single probe to the cathode electrode, and the cathode electrode radius (R), shows that, in both cases, the generated plasma temperatures decrease, and densities increase. The RDFT accurately depicts a dramatic decrease for L < R by 60% compared with the values for L > R. This indicates that, when L < R, the rate of plasma loss by diffusion is reduced. Under this investigation, the mechanical characteristics of treated and pre-treated Ihram Cotton Fabric Samples were compared under the Influence of the different two configurations of Plasma Cell discharge:

R > L > R

. These characteristics included resiliency, strain hardening, tensile strength, elongation percentage, yield strength, ultimate tensile strength, toughness, and fracture (breaking) point. Furthermore, the mechanism parameters of plasma interaction with textile membrane will be discussed, such as: process mechanism, interaction, and gas type. Full article

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

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9 pages, 5479 KiB

Open AccessArticle

The Effect of a Flexible Electrode on the Electro Deformability of an Actuating Unit of a MDI-Polyurethane Composite Fiber Membrane Filled with BaTiO₃

by Gang Lu, Changgeng Shuai, Yinsong Liu, Xue Yang and Xiaoyang Hu

Membranes 2022, 12(9), 878; https://doi.org/10.3390/membranes12090878 - 12 Sep 2022

Viewed by 1242

Abstract

The electro deformability of an actuating unit of a polyurethane dielectric elastomer (PUDE) is affected by many factors. The agglomeration of dielectric fillers faced by the traditional dielectric modification methods will lead to the instability of the actuation performance of dielectric composites. In [...] Read more.

The electro deformability of an actuating unit of a polyurethane dielectric elastomer (PUDE) is affected by many factors. The agglomeration of dielectric fillers faced by the traditional dielectric modification methods will lead to the instability of the actuation performance of dielectric composites. In addition, the electro deformability (ability of deformation after voltage loading) is great affected by the selection of flexible electrodes and packaging technology. Based on the research findings, Diphenylmethane-4,4′-diisocyanat (MDI)-polyurethane dielectric composite fiber membrane filled with barium titanate (BaTiO₃) is prepared using coaxial spinning, and this study then analyzes the effects of the types of flexible electrodes and coating methods on the electro deformability of the actuating unit of the dielectric composite fiber membrane. It is found that the electro deformability of the actuating unit coated with the single-walled carbon nanotube (SWNT) flexible electrode is better than that of the perfluoropolyether conductive grease (PCG) or the traditional conductive carbon grease (CCG) electrode in various degrees. When the loading voltage is 20 kV, the electro deformability of the actuating unit coated with SWNT flexible electrode exceeds the latter two electrodes by 13.8%; when the SWNT flexible electrode is encapsulated by physical surface implantation (PSI), the electric deformation of the actuating unit is higher than that of the solvent suspension dispersion (SSD). Full article

(This article belongs to the Special Issue Separation of Greenhouse Gases Using Hollow Fiber Membrane Contactor)

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17 pages, 5114 KiB

Open AccessArticle

Photocatalytic Performance Improvement by Doping Ag on ZnO/MWCNTs Nanocomposite Prepared with Pulsed Laser Ablation Method Based Photocatalysts Degrading Rhodamine B Organic Pollutant Dye

by Tahani A. Alrebdi, Reham A. Rezk, Shoug M. Alghamdi, Hoda A. Ahmed, Fatemah H. Alkallas, Rami Adel Pashameah, Ayman M. Mostafa and Eman A. Mwafy

Membranes 2022, 12(9), 877; https://doi.org/10.3390/membranes12090877 - 11 Sep 2022

Cited by 11 | Viewed by 2004

Abstract

ZnO/MWCNTs nanocomposite has significant potential in photocatalytic and environmental treatment. Unfortunately, its photocatalytic efficacy is not high enough due to its poor light absorbance and quick recombination of photo-generated carriers, which might be improved by incorporation with noble metal nanoparticles. Herein, Ag-doped ZnO/MWCNTs [...] Read more.

ZnO/MWCNTs nanocomposite has significant potential in photocatalytic and environmental treatment. Unfortunately, its photocatalytic efficacy is not high enough due to its poor light absorbance and quick recombination of photo-generated carriers, which might be improved by incorporation with noble metal nanoparticles. Herein, Ag-doped ZnO/MWCNTs nanocomposite was prepared using a pulsed laser ablation approach in the liquid media and examined as a degradable catalyst for Rhodamine B. (RhB). Different techniques were used to confirm the formation of the nanostructured materials (ZnO and Ag) and the complete interaction between them and MWCNTs. X-ray diffraction pattern revealed the hexagonal wurtzite crystal structure of ZnO and Ag. Additionally, UV-visible absorption spectrum was used to study the change throughout the shift in the transition energies, which affected the photocatalytic degradation. Furthermore, the morphological investigation by a scanning electron microscope showed the successful embedding and decoration of ZnO and Ag on the outer surface of CNTs. Moreover, the oxidation state of the formed final nanocomposite was investigated via an X-ray photoelectron spectrometer. After that, the photocatalytic degradations of RhB were tested using the prepared catalysts. The results showed that utilizing Ag significantly impacted the photo degradation of RhB by lowering the charge carrier recombination, leading to 95% photocatalytic degradation after 12 min. The enhanced photocatalytic performance of the produced nanocomposite was attributed to the role of the Ag dopant in generating more active oxygen species. Moreover, the impacts of the catalyst amount, pH level, and contact time were discussed. Full article

(This article belongs to the Special Issue Recent Advances in Membrane Filtration and Purification Technologies)

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9 pages, 7083 KiB

Open AccessArticle

Synthesis of Dimpled Particles by Seeded Emulsion Polymerization and Their Application in Superhydrophobic Coatings

by Likui Wang, Florian Ion Tiberiu Petrescu, Jing Liu, Hongping Li and Gang Shi

Membranes 2022, 12(9), 876; https://doi.org/10.3390/membranes12090876 - 11 Sep 2022

Cited by 3 | Viewed by 1551

Abstract

Dimpled particles are synthesized through the seeded polymerization of fluoroacrylate and styrene on swelled polystyrene spheres. The morphologies of the particles can be controlled by the polymerization temperature, the amount of solvent swelling the seeds or the ratio of the fluoroacrylate monomer over [...] Read more.

Dimpled particles are synthesized through the seeded polymerization of fluoroacrylate and styrene on swelled polystyrene spheres. The morphologies of the particles can be controlled by the polymerization temperature, the amount of solvent swelling the seeds or the ratio of the fluoroacrylate monomer over styrene. Golf-ball-like particles with many small dimples on their surfaces are obtained at low polymerization temperatures or with a small amount of solvent. Particles with a large single dimple are formed at higher polymerization temperatures, with larger solvent amounts or a higher ratio of fluoroacrylate over styrene. The morphology formation mechanism of these dimpled particles is proposed and the application of these particles in the fabrication of superhydrophobic coatings is demonstrated. Full article

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12 pages, 2376 KiB

Open AccessArticle

Modelling of Fractionated Condensation for Off-Flavours Reduction from Red Wine Fermentation Headspace

by Maria João Pereira, António Ferreira, Carla Brazinha and João Crespo

Membranes 2022, 12(9), 875; https://doi.org/10.3390/membranes12090875 - 10 Sep 2022

Viewed by 1410

Abstract

A mathematical model of fractionated condensation is proposed for predicting the recovery and fractionation of target aromas from red wine fermentation headspaces in order to remove off-flavours. The applicability of the model is assessed for two different alternative processes: fractionated condensation and vapour [...] Read more.

A mathematical model of fractionated condensation is proposed for predicting the recovery and fractionation of target aromas from red wine fermentation headspaces in order to remove off-flavours. The applicability of the model is assessed for two different alternative processes: fractionated condensation and vapour permeation–fractionated condensation. The aromas of the headspace of red wine fermentation are commonly lost through the fermenter venting system and are enhanced by the stripping effect of the produced CO₂. To mimic the operating conditions during the red wine fermentation, all experiments were performed at 30 °C with a red wine model solution containing relevant red wine aromas, the cosolvent ethanol at representative concentrations, and CO₂. Both studied processes allow for a good recovery of esters in the 2nd condenser, with over 80% of ethyl acetate and isoamyl acetate recovery when using vapour permeation–fractionated condensation and a recovery of 84–96% of all esters when using fractionated condensation. However, only the integrated process of vapour permeation–fractionated condensation achieves a significant decrease in the amount of ethyl phenols (off-flavours compounds) in the 1st condenser, above 50%, as expected due to the use of an organophilic membrane. The developed model was validated experimentally for the integrated process, proving to be a highly valuable tool for the prediction of aroma fractionation, aiming at the removal of off-flavours. Full article

(This article belongs to the Special Issue Membrane Technologies for Resource Recovery (Volume II))

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