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29 pages, 6975 KiB

Open AccessArticle

Development and Investigation of Hierarchically Structured Thin-Film Nanocomposite Membranes from Polyamide/Chitosan Succinate Embedded with a Metal-Organic Framework (Fe-BTC) for Pervaporation

by Tatiana Plisko, Katsiaryna Burts, Andrey Zolotarev, Alexandr Bildyukevich, Mariia Dmitrenko, Anna Kuzminova, Sergey Ermakov and Anastasia Penkova

Membranes 2022, 12(10), 967; https://doi.org/10.3390/membranes12100967 - 02 Oct 2022

Cited by 5 | Viewed by 1681

Abstract

Thin-film composite membranes (TFC) obtained by the formation of a selective layer on a porous membrane-substrate via interfacial polymerization (IP) are indispensable for separation procedures in reverse osmosis, nanofiltration, pervaporation, and gas separation. Achieving high selectivity and permeability for TFC membranes is still [...] Read more.

Thin-film composite membranes (TFC) obtained by the formation of a selective layer on a porous membrane-substrate via interfacial polymerization (IP) are indispensable for separation procedures in reverse osmosis, nanofiltration, pervaporation, and gas separation. Achieving high selectivity and permeability for TFC membranes is still one of the main challenges in membrane science and technology. This study focuses on the development of thin film nanocomposite (TFN) membranes with a hierarchically structured polyamide (PA)/chitosan succinate (ChS) selective layer embedded with a metal–organic framework of iron 1,3,5-benzenetricarboxylate (Fe-BTC) for the enhanced pervaporation dehydration of isopropanol. The aim of this work was to study the effect of Fe-BTC incorporation into the ChS interlayer and PA selective layer, obtained via IP, on the structure, properties, and performance of pervaporation TFN membranes. The structure and hydrophilicity of the developed TFN membranes were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM), along with water contact angle measurements. The developed TFN membranes were studied in the pervaporation dehydration of isopropanol (12–30 wt % water). It was found that incorporation of Fe-BTC into the ChS interlayer yielded the formation of a smoother, more uniform, and defect-free PA ultrathin selective layer via IP, due to the amorpho-crystalline structure of particles serving as the amine storage reservoir and led to an increase in membrane selectivity toward water, and a slight decrease in permeation flux compared to the ChS interlayered TFC membranes. The best pervaporation performance was demonstrated by the TFN membrane with a ChS-Fe-BTC interlayer and the addition of 0.03 wt % Fe-BTC in the PA layer, yielding a permeation flux of 197–826 g·m⁻²·h⁻¹ and 98.50–99.99 wt % water in the permeate, in the pervaporation separation of isopropanol/water mixtures (12–30 wt % water). Full article

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

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15 pages, 4135 KiB

Open AccessArticle

Chemical and Physical Ionic Liquids in CO₂ Capture System Using Membrane Vacuum Regeneration

by José Manuel Vadillo, Guillermo Díaz-Sainz, Lucía Gómez-Coma, Aurora Garea and Angel Irabien

Membranes 2022, 12(8), 785; https://doi.org/10.3390/membranes12080785 - 15 Aug 2022

Cited by 7 | Viewed by 1812

Abstract

Carbon Capture Utilization and Storage technologies are essential mitigation options to reach net-zero CO₂ emissions. However, this challenge requires the development of sustainable and economic separation technologies. This work presents a novel CO₂ capture technology strategy based on non-dispersive CO₂ [...] Read more.

Carbon Capture Utilization and Storage technologies are essential mitigation options to reach net-zero CO₂ emissions. However, this challenge requires the development of sustainable and economic separation technologies. This work presents a novel CO₂ capture technology strategy based on non-dispersive CO₂ absorption and membrane vacuum regeneration (MVR) technology, and employs two imidazolium ionic liquids (ILs), [emim][Ac] and [emim][MS], with different behavior to absorb CO₂. Continuous absorption–desorption experiments were carried out using polypropylene hollow fiber membrane contactors. The results show the highest desorption behavior in the case of [emim][Ac], with a MVR performance efficiency of 92% at 313 K and vacuum pressure of 0.04 bar. On the other hand, the IL [emim][MS] reached an efficiency of 83% under the same conditions. The MVR technology could increase the overall CO₂ capture performance by up to 61% for [emim][Ac] and 21% for [emim][MS], which represents an increase of 26% and 9%, respectively. Moreover, adding 30%vol. demonstrates that the process was only favorable by using the physical IL. The results presented here indicate the interest in membrane vacuum regeneration technology based on chemical ILs, but further techno-economic evaluation is needed to ensure the competitiveness of this novel CO₂ desorption approach for large-scale application. Full article

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

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16 pages, 9000 KiB

Open AccessArticle

The Effect of Solution Casting Temperature and Ultrasound Treatment on PEBAX MH-1657/ZIF-8 Mixed Matrix Membranes Morphology and Performance

by Elsa Lasseuguette, Louise Fielder-Dunton, Qian Jian and Maria-Chiara Ferrari

Membranes 2022, 12(6), 584; https://doi.org/10.3390/membranes12060584 - 31 May 2022

Cited by 3 | Viewed by 2140

Abstract

Approximately two-thirds of anthropogenic emissions causing global warming are from carbon dioxide. Carbon capture is essential, with membranes proving to be a low cost and energy-efficient solution to alternative technologies. In particular, mixed matrix membranes (MMMs) can have higher permeability and selectivity than [...] Read more.

Approximately two-thirds of anthropogenic emissions causing global warming are from carbon dioxide. Carbon capture is essential, with membranes proving to be a low cost and energy-efficient solution to alternative technologies. In particular, mixed matrix membranes (MMMs) can have higher permeability and selectivity than pure polymer membranes. The fabrication conditions affect the formation of defects within the membranes. In this work, MMMs were created using a PEBAX MH-1657 polymer and a ZIF-8 filler. The effect of casting plate temperature, varying from −5 °C to 50 °C, and the effect of ultrasound treatment time (80–400 min) and method (filler solution only, filler and polymer combined solution only and filler solution followed by combined solution) were investigated, aiming to reduce defect formations hence improving the performance of the MMMs. SEM images and permeation tests using pure CO₂ and N₂ gas, replicating flue gas for carbon capture, were used to investigate and compare the membranes morphology and performance. The results indicated that the MMMs maintained their permeabilities and selectivities at all tested casting temperatures. However, the neat PEBAX membranes demonstrated increased phase separation of the polyamide and polyether oxide phases at higher temperatures, causing a reduction in permeability due to the higher crystallinity degree, confirmed by DSC experiment. The MMMs fabricated at low ultrasound times displayed a large amount of aggregation with large particle size causing channeling. At high ultrasound times, a well-dispersed filler with small filler diameters was observed, providing a high membrane performance. Overall, defect-free membranes were successfully fabricated, leading to improved performance, with the best membrane resulting from the longest ultrasound time reaching the Robeson bound upper limits. Full article

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

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10 pages, 3993 KiB

Open AccessArticle

Dual-Structure PVDF/SDS Nanofibrous Membranes for Highly Efficient Personal Protection in Mines

by Gang Zhou, Rulin Liu, Qingfeng Xu, Kaili Wang, Yongmei Wang and Seeram Ramakrishna

Membranes 2022, 12(5), 482; https://doi.org/10.3390/membranes12050482 - 29 Apr 2022

Cited by 1 | Viewed by 1691

Abstract

Pneumoconiosis in miners is considered a global problem. Improving the performance of individual protective materials can effectively reduce the incidence of pneumoconiosis. In this study, the blend membrane of sodium dodecyl sulfate and polyvinylidene fluoride with a dual structure was prepared using electrospinning [...] Read more.

Pneumoconiosis in miners is considered a global problem. Improving the performance of individual protective materials can effectively reduce the incidence of pneumoconiosis. In this study, the blend membrane of sodium dodecyl sulfate and polyvinylidene fluoride with a dual structure was prepared using electrospinning techniques, and the morphological structure, fiber diameter, and filtration performance of the nanofiber membranes were optimized by adjusting the PVDF concentration and SDS content. The results show that the incorporation of SDS enabled the nanofiber membranes to show tree-like and beaded fibers. Compared with the original PVDF membrane, the small content of tree-like fibers and beaded fibers can improve the filtration efficiency and reduce the resistance of the fiber membrane. The prepared nanofiber membrane has excellent comprehensive filtration performance, and the quality factor is 0.042 pa⁻¹ when the concentration of PVDF is 10 wt% and the addition of SDS is 0.1 wt%. Furthermore, after high-temperature treatment, the membrane could still maintain good filtration performance. The PVDF/SDS blend nanofiber membrane has outstanding filtration efficiency and good thermal stability and can fully meet the personal protection of miners in underground high-temperature operation environments. Full article

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

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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 2337

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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19 pages, 5911 KiB

Open AccessArticle

Supported Liquid Membranes Based on Bifunctional Ionic Liquids for Selective Recovery of Gallium

by Haitao Zhou, Yuxi Ye, Yuefei Tan, Kailun Zhu, Xinmin Liu, Hongjing Tian, Qingjie Guo, Lingyun Wang, Shuju Zhao and Yang Liu

Membranes 2022, 12(4), 376; https://doi.org/10.3390/membranes12040376 - 30 Mar 2022

Cited by 5 | Viewed by 1711

Abstract

In this work, separation and recovery of gallium from aqueous solutions was examined using acid-base bifunctional ionic liquids (Bif-ILs) in both solvent extraction and supported liquid membrane (SLM) processes. The influence of a variety of parameters, such as feed acidity, extractant concentration and [...] Read more.

In this work, separation and recovery of gallium from aqueous solutions was examined using acid-base bifunctional ionic liquids (Bif-ILs) in both solvent extraction and supported liquid membrane (SLM) processes. The influence of a variety of parameters, such as feed acidity, extractant concentration and metal concentration on the solvent extraction behavior were evaluated. The slope method combined with FTIR spectroscopy was utilized to determine possible extraction mechanisms. The SLM containing Bif-ILs demonstrated highly selective facilitated transport of 96.2% Ga(III) from feed to stripping solution after optimization. During the evaluation of the separation performance of SLM for the transport of Ga(III), in the presence of Al(III), Mg(II), Cu(II) and Fe(II), 88.5% Ga(III) could be transported with only 6% Fe(II) and a nil quantity of other metals co-transported. SLM exhibited excellent long-time stability in five repeated transport cycles. Highly selective transport and separation performance was achieved using the SLM containing Bif-ILs, indicating considerable potential for application in Ga(III) recovery. Full article

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

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17 pages, 26053 KiB

Open AccessArticle

Preparation of Polyvinylidene Fluoride Nano-Filtration Membranes Modified with Functionalized Graphene Oxide for Textile Dye Removal

by Hirra Ahmad, Muhammad Zahid, Zulfiqar Ahmad Rehan, Anum Rashid, Saba Akram, Meshari M. H. Aljohani, Syed Khalid Mustafa, Tayyaba Khalid, Nader R. Abdelsalam, Rehab Y. Ghareeb and Mohammad S. AL-Harbi

Membranes 2022, 12(2), 224; https://doi.org/10.3390/membranes12020224 - 15 Feb 2022

Cited by 16 | Viewed by 2876

Abstract

Water scarcity has become one of the most significant problems globally. Membrane technology has gained considerable attention in water treatment technologies. Polymeric nanocomposite membranes are based on several properties, with enhanced water flux, high hydrophilicity and anti-biofouling behavior, improving the membrane performance, flexibility, [...] Read more.

Water scarcity has become one of the most significant problems globally. Membrane technology has gained considerable attention in water treatment technologies. Polymeric nanocomposite membranes are based on several properties, with enhanced water flux, high hydrophilicity and anti-biofouling behavior, improving the membrane performance, flexibility, cost-effectiveness and excellent separation properties. In this study, aminated graphene oxide (NH₂-GO)-based PVDF membranes were fabricated using a phase-inversion method for textile dye removal. These fabricated membranes showed the highest water flux at about 170.2 (J/L.h⁻¹.m⁻²) and 98.2% BSA rejection. Moreover, these membranes removed about 96.6% and 88.5% of methylene blue and methyl orange, respectively. Aminated graphene oxide-based polyvinylidene fluoride (PVDF) membranes emerge as a good membrane material that enhances the membrane performance. Full article

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

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16 pages, 6230 KiB

Open AccessArticle

Preparation and Separation Properties of Electrospinning Modified Membrane with Ionic Liquid Terminating Polyimide/Polyvinylpyrrolidone@Polydopamine

by Peng Qi, Hongge Jia, Shuangping Xu, Qingji Wang, Guiming Su, Guoxing Yang, Mingyu Zhang, Yanqing Qu and Fuying Pei

Membranes 2022, 12(2), 189; https://doi.org/10.3390/membranes12020189 - 05 Feb 2022

Cited by 2 | Viewed by 1956

Abstract

In this paper, superhydrophilic polyimide (PI) membranes were prepared using the electrostatic spinning method, capped with a hydrophilic ionic liquid (IL), and blended with polyvinylpyrrolidone (PVP). Using this preparation, the surface of the fiber membranes was coated in polydopamine (PDA) by means of [...] Read more.

In this paper, superhydrophilic polyimide (PI) membranes were prepared using the electrostatic spinning method, capped with a hydrophilic ionic liquid (IL), and blended with polyvinylpyrrolidone (PVP). Using this preparation, the surface of the fiber membranes was coated in polydopamine (PDA) by means of an in-growth method. Scanning electron micrographs showed prepared blend films can form continuous fibers, for whom the distributions of diameter and pore were uniform. Post-modification (carried out by adding hydrophilic substances), the ability of the membrane surface to adhere to water was also significantly improved. The water contact angle was reduced from 128.97 ± 3.86° in unmodified PI to 30.26 ± 2.16°. In addition, they displayed a good separation effect on emulsified oil/water mixtures. The membrane flux reached a maximum value of 290 L·m⁻²·h⁻¹, with a maximum separation efficiency reached of more than 99%. After being recycled 10 times, the separation efficiency maintained a level exceeding 95%. The purpose of this study is to demonstrate the simplicity and efficiency of this experiment, thereby providing new ideas for the future application of membrane separation technology in wastewater treatment. Full article

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

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18 pages, 3123 KiB

Open AccessArticle

Optimal Water Backwashing Condition in Combined Water Treatment of Alumina Microfiltration and PP Beads

by Hyungmin Cho, Gihoon Yoon, Minjae Kim and Jin Yong Park

Membranes 2022, 12(1), 92; https://doi.org/10.3390/membranes12010092 - 15 Jan 2022

Cited by 2 | Viewed by 1752

Abstract

Membrane fouling is a dominant limit of the membrane separation process. In this research, the optimal water backwashing to solve the membrane fouling problem was investigated in the combined water treatment process of alumina MF and pure polypropylene (PP) beads. Additionally, the influence [...] Read more.

Membrane fouling is a dominant limit of the membrane separation process. In this research, the optimal water backwashing to solve the membrane fouling problem was investigated in the combined water treatment process of alumina MF and pure polypropylene (PP) beads. Additionally, the influence of membrane shape (tubular or seven channel) was examined, depending on the water backwashing period. The optimal backwashing time (BT) could be 20 s in the combined water treatment process, because of the highest total treated volume (V_T) in our BT 6–30 s conditions. The optimal backwashing period (BP) could be 6 min, because of the minimum membrane fouling and the maximum V_T in the combined process of tubular alumina MF and PP beads. The resistance of reversible membrane fouling (R_rf) showed a major resistance of total membrane fouling, and that of irreversible membrane fouling (R_if) was a minor one, in the combined process using tubular or seven channel MF. The R_if showed a decreasing trend obviously, as decreasing BT from NBW to 2 min for seven channel MF. It means that the more frequent water backwashing could be more effective to control the membrane fouling, especially irreversible fouling, for seven channel membranes than tubular membranes. Full article

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

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23 pages, 5074 KiB

Open AccessArticle

The Optimization of Dispersion and Application Techniques for Nanocarbon-Doped Mixed Matrix Gas Separation Membranes

by Ruben Hammerstein, Tim Schubert, Gerd Braun, Tobias Wolf, Stéphan Barbe, Antje Quade, Rüdiger Foest, Dionysios S. Karousos and Evangelos P. Favvas

Membranes 2022, 12(1), 87; https://doi.org/10.3390/membranes12010087 - 13 Jan 2022

Cited by 7 | Viewed by 1781

Abstract

In this work, supported cellulose acetate (CA) mixed matrix membranes (MMMs) were prepared and studied concerning their gas separation behaviors. The dispersion of carbon nanotube fillers were studied as a factor of polymer and filler concentrations using the mixing methods of the rotor–stator [...] Read more.

In this work, supported cellulose acetate (CA) mixed matrix membranes (MMMs) were prepared and studied concerning their gas separation behaviors. The dispersion of carbon nanotube fillers were studied as a factor of polymer and filler concentrations using the mixing methods of the rotor–stator system (RS) and the three-roll-mill system (TRM). Compared to the dispersion quality achieved by RS, samples prepared using the TRM seem to have slightly bigger, but fewer and more homogenously distributed, agglomerates. The green γ-butyrolactone (GBL) was chosen as a polyimide (PI) polymer-solvent, whereas diacetone alcohol (DAA) was used for preparing the CA solutions. The coating of the thin CA separation layer was applied using a spin coater. For coating on the PP carriers, a short parameter study was conducted regarding the plasma treatment to affect the wettability, the coating speed, and the volume of dispersion that was applied to the carrier. As predicted by the parameter study, the amount of dispersion that remained on the carriers decreased with an increasing rotational speed during the spin coating process. The dry separation layer thickness was varied between about 1.4 and 4.7 μm. Electrically conductive additives in a non-conductive matrix showed a steeply increasing electrical conductivity after passing the so-called percolation threshold. This was used to evaluate the agglomeration behavior in suspension and in the applied layer. Gas permeation tests were performed using a constant volume apparatus at feed pressures of 5, 10, and 15 bar. The highest calculated CO₂/N₂ selectivity (ideal), 21, was achieved for the CA membrane and corresponded to a CO₂ permeability of 49.6 Barrer. Full article

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

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12 pages, 4996 KiB

Open AccessArticle

Optimization of a MOF Blended with Modified Polyimide Membrane for High-Performance Gas Separation

by Yushu Zhang, Hongge Jia, Qingji Wang, Wenqiang Ma, Guoxing Yang, Shuangping Xu, Shaobin Li, Guiming Su, Yanqing Qu, Mingyu Zhang and Pengfei Jiang

Membranes 2022, 12(1), 34; https://doi.org/10.3390/membranes12010034 - 27 Dec 2021

Cited by 12 | Viewed by 3248

Abstract

The preparation, characterization and gas separation properties of mixed matrix membranes (MMMs) were obtained from polyimide capped with ionic liquid and blended with metal-organic frameworks (MOFs). The synthesized MOF was amine functionalized to produce UiO-66-NH₂, and its amino group has a [...] Read more.

The preparation, characterization and gas separation properties of mixed matrix membranes (MMMs) were obtained from polyimide capped with ionic liquid and blended with metal-organic frameworks (MOFs). The synthesized MOF was amine functionalized to produce UiO-66-NH₂, and its amino group has a higher affinity for CO₂. Mixed matrix membranes exhibited good membrane forming ability, heat resistance and mechanical properties. The polyimide membrane exclusively capped by ionic liquid exhibited good permselectivity of 74.1 for CO₂/CH₄, which was 6.2 times that of the pure polyimide membrane. It is worth noting that MMM blended with UiO-66-NH₂ demonstrated the highest ideal selectivity for CO₂/CH₄ (95.1) with a CO₂ permeability of 7.61 Barrer, which is close to the 2008 Robeson upper bound. The addition of UiO-66-NH₂ and ionic liquid enhanced the permselectivity of MMMs, which may be one of the promising technologies for high performance CO₂/CH₄ gas separation. Full article

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

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32 pages, 13930 KiB

Open AccessArticle

Impact of Ionic Liquid Structure and Loading on Gas Sorption and Permeation for ZIF-8-Based Composites and Mixed Matrix Membranes

by Paloma Ortiz-Albo, Tiago J. Ferreira, Carla F. Martins, Vitor Alves, Isabel A. A. C. Esteves, Luís Cunha-Silva, Izumi Kumakiri, João Crespo and Luísa A. Neves

Membranes 2022, 12(1), 13; https://doi.org/10.3390/membranes12010013 - 23 Dec 2021

Cited by 10 | Viewed by 3286

Abstract

Carbon dioxide (CO₂) capture has become of great importance for industrial processes due to the adverse environmental effects of gas emissions. Mixed matrix membranes (MMMs) have been studied as an alternative to traditional technologies, especially due to their potential to overcome [...] Read more.

Carbon dioxide (CO₂) capture has become of great importance for industrial processes due to the adverse environmental effects of gas emissions. Mixed matrix membranes (MMMs) have been studied as an alternative to traditional technologies, especially due to their potential to overcome the practical limitations of conventional polymeric and inorganic membranes. In this work, the effect of using different ionic liquids (ILs) with the stable metal–organic framework (MOF) ZIF-8 was evaluated. Several IL@ZIF-8 composites and IL@ZIF-8 MMMs were prepared to improve the selective CO₂ sorption and permeation over other gases such as methane (CH₄) and nitrogen (N₂). Different ILs and two distinct loadings were prepared to study not only the effect of IL concentration, but also the impact of the IL structure and affinity towards a specific gas mixture separation. Single gas sorption studies showed an improvement in CO₂/CH₄ and CO₂/N₂ selectivities, compared with the ones for the pristine ZIF-8, increasing with IL loading. In addition, the prepared IL@ZIF-8 MMMs showed improved CO₂ selective behavior and mechanical strength with respect to ZIF-8 MMMs, with a strong dependence on the intrinsic IL CO₂ selectivity. Therefore, the selection of high affinity ILs can lead to the improvement of CO₂ selective separation for IL@ZIF-8 MMMs. Full article

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

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17 pages, 53365 KiB

Open AccessArticle

Organo-Functionalization: An Effective Method in Enhancing the Separation and Antifouling Performance of Thin-Film Nanocomposite Membranes by Improving the Uniform Dispersion of Palygorskite Nanoparticles

by Liu Yang, Qianwen Zhang, Qikun Wang, Wande Ding and Kefeng Zhang

Membranes 2021, 11(11), 889; https://doi.org/10.3390/membranes11110889 - 19 Nov 2021

Cited by 5 | Viewed by 1659

Abstract

Recently, palygorskite (Pal) has become a promising new membrane additive in flux enhancement and fouling reduction, which is an environmentally friendly nanoclay material under the 2:1 layer composition with 1D tubular structure. However, the aggregation of Pal due to the intermolecular forces is [...] Read more.

Recently, palygorskite (Pal) has become a promising new membrane additive in flux enhancement and fouling reduction, which is an environmentally friendly nanoclay material under the 2:1 layer composition with 1D tubular structure. However, the aggregation of Pal due to the intermolecular forces is still an obstacle to be solved in improving membrane performance. Herein, Pal nanoparticles were chemically modified by KH550 to weaken the aggregation and improve the dispersibility, and then incorporated into the organic phase to prepare thin-film nanocomposite (TFN) membranes. The results showed that the organo-functionalization could effectively improve the membrane hydrophilicity and dispersion of Pal nanoparticles in the polyamide layer, which contributed to the enhanced water flux (from 25 to 38 L/m²·h), unchanged salt rejection (98.0%) and better antifouling capacity (91% flux recovery rate), which suggested that the organo-functionalization of nanoparticles was an efficient method in further enhancing membrane performance Full article

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

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24 pages, 3155 KiB

Open AccessArticle

CO₂/CH₄ and H₂/CH₄ Gas Separation Performance of CTA-TNT@CNT Hybrid Mixed Matrix Membranes

by Chhabilal Regmi, Saeed Ashtiani, Zdeněk Hrdlička and Karel Friess

Membranes 2021, 11(11), 862; https://doi.org/10.3390/membranes11110862 - 09 Nov 2021

Cited by 15 | Viewed by 2977

Abstract

This study explored the underlying synergy between titanium dioxide nanotube (TNT) and carbon nanotube (CNT) hybrid fillers in cellulose triacetate (CTA)-based mixed matrix membranes (MMMs) for natural gas purification. The CNT@TNT hybrid nanofillers were blended with CTA polymer and cast as a thin [...] Read more.

This study explored the underlying synergy between titanium dioxide nanotube (TNT) and carbon nanotube (CNT) hybrid fillers in cellulose triacetate (CTA)-based mixed matrix membranes (MMMs) for natural gas purification. The CNT@TNT hybrid nanofillers were blended with CTA polymer and cast as a thin film by a facile casting technique, after which they were used for single gas separation. The hybrid filler-based membrane depicted a higher CO₂ uptake affinity than the single filler (CNT/TNT)-based membrane. The gas separation results indicate that the hybrid fillers (TNT@CNT) are strongly selective for CO₂ over CH₄ and H₂ over CH₄. The increment in the CO₂/CH₄ and H₂/CH₄ selectivities compared to the pristine CTA membrane was 42.98 from 25.08 and 48.43 from 36.58, respectively. Similarly, the CO₂ and H₂ permeability of the CTA-TNT@CNT membrane increased by six- and five-fold, respectively, compared to the pristine CTA membrane. Such significant improvements in CO₂/CH₄ and H₂/CH₄ separation performance and thermal and mechanical properties suggest a feasible and practical approach for potential biogas upgrading and natural gas purification. Full article

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

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17 pages, 17592 KiB

Open AccessArticle

Application of Response Surface Methodology (RSM) for the Optimization of Chromium(III) Synergistic Extraction by Supported Liquid Membrane

by Jakub Rajewski and Agnieszka Dobrzyńska-Inger

Membranes 2021, 11(11), 854; https://doi.org/10.3390/membranes11110854 - 04 Nov 2021

Cited by 24 | Viewed by 2498

Abstract

In this paper, the response surface methodology (RSM) was proposed for studying the synergistic extraction of chromium(III) ions by double-carrier supported liquid membrane (DCSLM) with organophosphorus carriers (D2EHPA/Cyanex272). At first, the optimization method of “one-factor-at-a-time” was adopted for determination of the best conditions [...] Read more.

In this paper, the response surface methodology (RSM) was proposed for studying the synergistic extraction of chromium(III) ions by double-carrier supported liquid membrane (DCSLM) with organophosphorus carriers (D2EHPA/Cyanex272). At first, the optimization method of “one-factor-at-a-time” was adopted for determination of the best conditions for Cr(III) extraction by SLM with only one carrier (D2EHPA). The optimum/threshold D2EHPA concentration in the membrane phase increased linearly with initial concentration of Cr(III) ions in the feed phase. After the addition the second carrier (Cyanex272), the synergistic effect was observed. The largest percentage of extraction and the shorter time was obtained. The optimization of the synergistic extraction in DCSLM system by RSM using Box–Behnken design (BBD) for three variables (concentration and proportions of the carriers, initial concentration of Cr(III), and time of the process) was studied. The statistical model was verified with the analysis of variance (ANOVA) for the response surface quadratic model. The reduced quadratic model showed that the predicted values were in agreement with those obtained experimentally, as well as the fact that the concentrations and proportions of the carriers had a significant influence on the response. The developed model was considered to be verified and can be used to predict the optimal condition for the chromium ions extraction. Full article

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

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11 pages, 1795 KiB

Open AccessEditor’s ChoiceArticle

Biphenyl-Based Covalent Triazine Framework/Matrimid^® Mixed-Matrix Membranes for CO₂/CH₄ Separation

by Stefanie Bügel, Quang-Dien Hoang, Alex Spieß, Yangyang Sun, Shanghua Xing and Christoph Janiak

Membranes 2021, 11(10), 795; https://doi.org/10.3390/membranes11100795 - 19 Oct 2021

Cited by 6 | Viewed by 2729

Abstract

Processes, such as biogas upgrading and natural gas sweetening, make CO₂/CH₄ separation an environmentally relevant and current topic. One way to overcome this separation issue is the application of membranes. An increase in separation efficiency can be achieved by applying [...] Read more.

Processes, such as biogas upgrading and natural gas sweetening, make CO₂/CH₄ separation an environmentally relevant and current topic. One way to overcome this separation issue is the application of membranes. An increase in separation efficiency can be achieved by applying mixed-matrix membranes, in which filler materials are introduced into polymer matrices. In this work, we report the covalent triazine framework CTF-biphenyl as filler material in a matrix of the glassy polyimide Matrimid^®. MMMs with 8, 16, and 24 wt% of the filler material are applied for CO₂/CH₄ mixed-gas separation measurements. With a CTF-biphenyl loading of only 16 wt%, the CO₂ permeability is more than doubled compared to the pure polymer membrane, while maintaining the high CO₂/CH₄ selectivity of Matrimid^®. Full article

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

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16 pages, 4428 KiB

Open AccessArticle

Fabrication and Characterization of Sulfonated Graphene Oxide (SGO) Doped PVDF Nanocomposite Membranes with Improved Anti-Biofouling Performance

by Muhammad Zahid, Tayyaba Khalid, Zulfiqar Ahmad Rehan, Talha Javed, Saba Akram, Anum Rashid, Syed Khalid Mustafa, Rubab Shabbir, Freddy Mora-Poblete, Muhammad Shoaib Asad, Rida Liaquat, Mohamed M. Hassan, Mohammed A. Amin and Hafiz Abdul Shakoor

Membranes 2021, 11(10), 749; https://doi.org/10.3390/membranes11100749 - 29 Sep 2021

Cited by 12 | Viewed by 2261

Abstract

Emergence of membrane technology for effective performance is qualified due to its low energy consumption, no use of chemicals, high removal capacity and easy accessibility of membrane material. The hydrophobic nature of polymeric membranes limits their applications due to biofouling (assemblage of microorganisms [...] Read more.

Emergence of membrane technology for effective performance is qualified due to its low energy consumption, no use of chemicals, high removal capacity and easy accessibility of membrane material. The hydrophobic nature of polymeric membranes limits their applications due to biofouling (assemblage of microorganisms on surface of membrane). Polymeric nanocomposite membranes emerge to alleviate this issue. The current research work was concerned with the fabrication of sulfonated graphene oxide doped polyvinylidene fluoride (PVDF) membrane and investigation of its anti-biofouling and anti-bacterial behavior. The membrane was fabricated through phase inversion method, and its structure and morphology were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-rays diffraction (XRD) and thermo gravimetric analysis (TGA) techniques. Performance of the membrane was evaluated via pure water flux; anti-biofouling behavior was determined through Bovine Serum albumin (BSA) rejection. Our results revealed that the highest water flux was shown by M7 membrane about 308.7 Lm⁻²h⁻¹/bar having (0.5%) concentration of SGO with improved BSA rejection. Furthermore, these fabricated membranes showed high antibacterial activity, more hydrophilicity and mechanical strength as compared to pristine PVDF membranes. It was concluded that SGO addition within PVDF polymer matrix enhanced the properties and performance of membranes. Therefore, SGO was found to be a promising material for the fabrication of nanocomposite membranes. Full article

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

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Review

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15 pages, 67175 KiB

Open AccessReview

A Review of the Application of Modified Separators in Inhibiting the “shuttle effect” of Lithium–Sulfur Batteries

by Bo-Wen Zhang, Bo Sun, Pei Fu, Feng Liu, Chen Zhu, Bao-Ming Xu, Yong Pan and Chi Chen

Membranes 2022, 12(8), 790; https://doi.org/10.3390/membranes12080790 - 17 Aug 2022

Cited by 16 | Viewed by 2986

Abstract

Lithium-sulfur batteries with high theoretical specific capacity and high energy density are considered to be one of the most promising energy storage devices. However, the “shuttle effect” caused by the soluble polysulphide intermediates migrating back and forth between the positive and negative electrodes [...] Read more.

Lithium-sulfur batteries with high theoretical specific capacity and high energy density are considered to be one of the most promising energy storage devices. However, the “shuttle effect” caused by the soluble polysulphide intermediates migrating back and forth between the positive and negative electrodes significantly reduces the active substance content of the battery and hinders the commercial applications of lithium–sulfur batteries. The separator being far from the electrochemical reaction interface and in close contact with the electrode poses an important barrier to polysulfide shuttle. Therefore, the electrochemical performance including coulombic efficiency and cycle stability of lithium–sulfur batteries can be effectively improved by rationally designing the separator. In this paper, the research progress of the modification of lithium–sulfur battery separators is reviewed from the perspectives of adsorption effect, electrostatic effect, and steric hindrance effect, and a novel modification of the lithium–sulfur battery separator is prospected. Full article

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

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10 pages, 2204 KiB

Open AccessReview

Recent Progress of Adsorptive Ultrafiltration Membranes in Water Treatment—A Mini Review

by Tong Yu, Jing Zhou, Feng Liu, Bao-Ming Xu and Yong Pan

Membranes 2022, 12(5), 519; https://doi.org/10.3390/membranes12050519 - 13 May 2022

Cited by 18 | Viewed by 3451

Abstract

Adsorptive ultrafiltration mixed matrix membranes (MMMs) are a new strategy, developed in recent years, to remove harmful cations and small-molecule organics from wastewater and drinking water, which achieve ultrafiltration and adsorption functions in one unit and are considered to be among the promising [...] Read more.

Adsorptive ultrafiltration mixed matrix membranes (MMMs) are a new strategy, developed in recent years, to remove harmful cations and small-molecule organics from wastewater and drinking water, which achieve ultrafiltration and adsorption functions in one unit and are considered to be among the promising technologies that have exhibited efficiency and competence in water reuse. This mini review concerns the research progress of adsorptive ultrafiltration MMMs for removing heavy metal ions and small-molecule organics. We firstly introduce the types and classifications of adsorptive ultrafiltration MMMs (their classifications can be established based on the type of the adsorbent used). Furthermore, we discuss the removal mechanism of adsorptive ultrafiltration MMMs, as well as summarizing the main fabrication techniques for adsorptive ultrafiltration membranes. In addition, we identified some of the issues and challenges of the practical application for adsorptive ultrafiltration. Full article

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

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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 3125

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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16 pages, 1926 KiB

Open AccessReview

Enhanced Specific Mechanism of Separation by Polymeric Membrane Modification—A Short Review

by Anna Siekierka, Katarzyna Smolińska-Kempisty and Joanna Wolska

Membranes 2021, 11(12), 942; https://doi.org/10.3390/membranes11120942 - 29 Nov 2021

Cited by 11 | Viewed by 2679

Abstract

Membrane technologies have found a significant application in separation processes in an exceeding range of industrial fields. The crucial part that is decided regarding the efficiency and effectivity of separation is the type of membrane. The membranes deal with separation problems, working under [...] Read more.

Membrane technologies have found a significant application in separation processes in an exceeding range of industrial fields. The crucial part that is decided regarding the efficiency and effectivity of separation is the type of membrane. The membranes deal with separation problems, working under the various mechanisms of transportation of selected species. This review compares significant types of entrapped matter (ions, compounds, and particles) within membrane technology. The ion-exchange membranes, molecularly imprinted membranes, smart membranes, and adsorptive membranes are investigated. Here, we focus on the selective separation through the above types of membranes and detect their preparation methods. Firstly, the explanation of transportation and preparation of each type of membrane evaluated is provided. Next, the working and application phenomena are evaluated. Finally, the review discusses the membrane modification methods and briefly provides differences in the properties that occurred depending on the type of materials used and the modification protocol. Full article

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

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