Special Issue "Zeolitic Membranes for Gas and Liquid Separation: Synthesis and Applications"

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

Deadline for manuscript submissions: 10 July 2023 | Viewed by 3444

Special Issue Editors

School of Energy, Materials and Chemical Engineering, Hefei University, Hefei 230601, China
Interests: inorganic membrane; zeolite membrane; organic membrane; gas separation; pervaporation; membrane reactor; structure control; SiC membrane
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 210009, China
Interests: inorganic membrane; zeolite membrane; gas separation; pervaporation; membrane reactor

Special Issue Information

Dear Colleagues,

Membrane separation is one of the most critical and challenging steps for industrial processes, and zeolite membranes are potential candidates to be used for this application. Zeolites are microporous materials that possess molecular-sieving and selective-adsorption properties. The preparation of a zeolite membrane has advanced our understanding of continuous separation processes, as many milestones have been reached through research and experiments.

This Special Issue on “Zeolitic Membranes for Gas and Liquid Separation: Synthesis and Applications” focuses on the recent theoretical and experimental advances in materials chemistry and membrane synthesis, processing, characterization, simulation, and performance, including the issues faced in the design and growth of membranes for gas and liquid separation applications.

This Special Issue aims to highlight and promote recent advances and to create an overview of research activities on zeolitic membrane processes. The topics of interest include, but are not limited to, the following: zeolite and zeolitic metal–organic frameworks (MOFs) for gas and liquid separation; novel membrane materials; novel membrane formation methods; and modification techniques. Concerning applications, apart from gas separation and liquid separation (pervaporation and filtration), membrane reactors have also been an attractive research topic.

In this Special Issue, original research articles and reviews are welcome. We look forward to receiving your contributions. 

Dr. Qing Wang
Dr. Bin Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • zeolite membrane
  • metal–organic frameworks
  • nanostructured materials
  • mixed-matrix membrane
  • hybrid membrane
  • hollow fiber membrane
  • 2D membrane
  • gas separation
  • liquid separation
  • pervaporation/vapor permeation
  • membrane reactor
  • water treatment
  • desalination
  • CO2 capture
  • synthesis
  • characterization

Published Papers (5 papers)

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Research

Article
A Facile Way to Fabricate GO-EDA/Al2O3 Tubular Nanofiltration Membranes with Enhanced Desalination Stability via Fine-Tuning the pH of the Membrane-Forming Suspensions
Membranes 2023, 13(5), 536; https://doi.org/10.3390/membranes13050536 - 22 May 2023
Viewed by 399
Abstract
Pristine graphene oxide (GO)-based membranes have proven promising for molecular and ion separation owing to efficient molecular transport nanochannels, but their separation ability in an aqueous environment is limited by the natural swelling tendency of GO. To obtain a novel membrane with anti-swelling [...] Read more.
Pristine graphene oxide (GO)-based membranes have proven promising for molecular and ion separation owing to efficient molecular transport nanochannels, but their separation ability in an aqueous environment is limited by the natural swelling tendency of GO. To obtain a novel membrane with anti-swelling behavior and remarkable desalination capability, we used the Al2O3 tubular membrane with an average pore size of 20 nm as the substrate and fabricated several GO nanofiltration ceramic membranes with different interlayer structures and surface charges by fine-tuning the pH of the GO-EDA membrane-forming suspension (pH = 7, 9, 11). The resultant membranes could maintain desalination stability, whether immersed in water for 680 h or operated under a high-pressure environment. When the pH of the membrane-forming suspension was 11, the prepared GE-11 membrane showed a rejection of 91.5% (measured at 5 bar) towards 1 mM Na2SO4 after soaking in water for 680 h. An increase in the transmembrane pressure to 20 bar resulted in an increase in the rejection towards the 1 mM Na2SO4 solution to 96.3%, and an increase in the permeance to 3.7 L·m−2·h−1·bar−1. The proposed strategy in varying charge repulsion is beneficial to the future development of GO-derived nanofiltration ceramic membranes. Full article
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Article
Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba0.5Sr0.5Co0.8Fe0.2O3-δ Membranes during Aging
Membranes 2023, 13(5), 504; https://doi.org/10.3390/membranes13050504 - 10 May 2023
Viewed by 654
Abstract
The separation of oxygen from air by means of inorganic ceramic membranes requires gas-tight ceramic–metal joints that enable reliable permeation operation in the oxygen partial pressure gradient at 850 °C. Reactive air brazing is a promising method to solve this challenge. However, reactive [...] Read more.
The separation of oxygen from air by means of inorganic ceramic membranes requires gas-tight ceramic–metal joints that enable reliable permeation operation in the oxygen partial pressure gradient at 850 °C. Reactive air brazing is a promising method to solve this challenge. However, reactive air brazed BSCF membranes suffer from a significant strength degradation that is caused by unhindered diffusion from the metal component during aging. In this study, we investigated how diffusion layers applied on the austenitic steel AISI 314 influence the bending strength of BSCF-Ag3CuO-AISI314 joints after aging. Three different approaches were compared as diffusion barriers: (1) aluminizing via pack cementation, (2) spray coating with NiCoCrAlReY, and (3) spray coating with NiCoCrAlReY and an additional 7YSZ top layer. Coated steel components were brazed to bending bars and aged for 1000 h at 850 °C in air prior to four-point bending and subsequent macroscopic as well microscopic analyses. In particular, coating with NiCoCrAlReY showed low-defect microstructures. The characteristic joint strength was raised from 17 MPa to 35 MPa after 1000 h aging at 850 °C. In addition, the dominant delamination fracture between the steel and the mixed oxide layer, observed in the reference series with uncoated steel, could be replaced by mixed and ceramic fractures of higher strength. The effect of residual joint stresses on the crack formation and path is analyzed and discussed. Chromium poisoning could no longer be detected in the BSCF, and interdiffusion through the braze was effectively reduced. Since the strength degradation of reactive air brazed joints is mainly caused by the metallic joining partner, the findings on the effect of the diffusion barriers in BSCF joints might be transferred to numerous other joining systems. Full article
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Article
Preparation and Lithium-Ion Separation Property of ZIF-8 Membrane with Excellent Flexibility
Membranes 2023, 13(5), 500; https://doi.org/10.3390/membranes13050500 - 09 May 2023
Viewed by 631
Abstract
Metal-organic framework (MOF) membranes exhibit immense potential for separation applications due to their regular pore channels and scalable pore sizes. However, structuring a flexible and high-quality MOF membrane remains a challenge due to its brittleness, which severely restricts its practical application. This paper [...] Read more.
Metal-organic framework (MOF) membranes exhibit immense potential for separation applications due to their regular pore channels and scalable pore sizes. However, structuring a flexible and high-quality MOF membrane remains a challenge due to its brittleness, which severely restricts its practical application. This paper presents a simple and effective method in which continuous, uniform, defect-free ZIF-8 film layers of tunable thickness are constructed on the surface of inert microporous polypropylene membranes (MPPM). To provide heterogeneous nucleation sites for ZIF-8 growth, an extensive amount of hydroxyl and amine groups were introduced on the MPPM surface using the dopamine-assisted co-deposition technique. Subsequently, ZIF-8 crystals were grown in-situ on the MPPM surface using the solvothermal method. The resultant ZIF-8/MPPM exhibited a lithium-ion permeation flux of 0.151 mol m−2 h−1 and a high selectivity of Li+/Na+ = 1.93, Li+/Mg2+ = 11.50. Notably, ZIF-8/MPPM has good flexibility, and the lithium-ion permeation flux and selectivity remain unchanged at a bending curvature of 348 m−1. These excellent mechanical characteristics are crucial for the practical applications of MOF membranes. Full article
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Article
Efficient Pervaporation for Ethanol Dehydration: Ultrasonic Spraying Preparation of Polyvinyl Alcohol (PVA)/Ti3C2Tx Nanosheet Mixed Matrix Membranes
Membranes 2023, 13(4), 430; https://doi.org/10.3390/membranes13040430 - 13 Apr 2023
Viewed by 678
Abstract
Polyvinyl alcohol (PVA) pervaporation (PV) membranes have been extensively studied in the field of ethanol dehydration. The incorporation of two-dimensional (2D) nanomaterials into the PVA matrix can greatly improve the hydrophilicity of the PVA polymer matrix, thereby enhancing its PV performance. In this [...] Read more.
Polyvinyl alcohol (PVA) pervaporation (PV) membranes have been extensively studied in the field of ethanol dehydration. The incorporation of two-dimensional (2D) nanomaterials into the PVA matrix can greatly improve the hydrophilicity of the PVA polymer matrix, thereby enhancing its PV performance. In this work, self-made MXene (Ti3C2Tx-based) nanosheets were dispersed in the PVA polymer matrix, and the composite membranes were fabricated by homemade ultrasonic spraying equipment with poly(tetrafluoroethylene) (PTFE) electrospun nanofibrous membrane as support. Due to the gentle coating of ultrasonic spraying and following continuous steps of drying and thermal crosslinking, a thin (~1.5 μm), homogenous and defect-free PVA-based separation layer was fabricated on the PTFE support. The prepared rolls of the PVA composite membranes were investigated systematically. The PV performance of the membrane was significantly improved by increasing the solubility and diffusion rate of the membranes to the water molecules through the hydrophilic channels constructed by the MXene nanosheets in the membrane matrix. The water flux and separation factor of the PVA/MXene mixed matrix membrane (MMM) were dramatically increased to 1.21 kg·m−2·h−1 and 1126.8, respectively. With high mechanical strength and structural stability, the prepared PGM-0 membrane suffered 300 h of the PV test without any performance degradation. Considering the promising results, it is likely that the membrane would improve the efficiency of the PV process and reduce energy consumption in the ethanol dehydration. Full article
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Article
In Situ Incorporation of TiO2@Graphene Oxide (GO) Nanosheets in Polyacrylonitrile (PAN)-Based Membranes Matrix for Ultrafast Protein Separation
Membranes 2023, 13(4), 377; https://doi.org/10.3390/membranes13040377 - 26 Mar 2023
Viewed by 597
Abstract
Organic polymeric ultrafiltration (UF) membranes have been widely used in protein separation due to their advantages of high flux and simple manufacturing process. However, due to the hydrophobic nature of the polymer, pure polymeric UF membranes need to be modified or hybrid to [...] Read more.
Organic polymeric ultrafiltration (UF) membranes have been widely used in protein separation due to their advantages of high flux and simple manufacturing process. However, due to the hydrophobic nature of the polymer, pure polymeric UF membranes need to be modified or hybrid to increase their flux and anti-fouling performance. In this work, tetrabutyl titanate (TBT) and graphene oxide (GO) were simultaneously added to the polyacrylonitrile (PAN) casting solution to prepare a TiO2@GO/PAN hybrid ultrafiltration membrane using a non-solvent induced phase separation (NIPS). During the phase separation process, TBT underwent a sol–gel reaction to generate hydrophilic TiO2 nanoparticles in situ. Some of the generated TiO2 nanoparticles reacted with the GO through a chelation interaction to form TiO2@GO nanocomposites. The resulting TiO2@GO nanocomposites had higher hydrophilicity than the GO. They could selectively segregate towards the membrane surface and pore walls through the solvent and non-solvent exchange during the NIPS, significantly improving the membrane’s hydrophilicity. The remaining TiO2 nanoparticles were segregated from the membrane matrix to increase the membrane’s porosity. Furthermore, the interaction between the GO and TiO2 also restricted the excessive segregation of the TiO2 nanoparticles and reduced their losing. The resulting TiO2@GO/PAN membrane had a water flux of 1487.6 L·m−2·h−1 and a bovine serum albumin (BSA) rejection rate of 99.5%, which were much higher than those of the currently available UF membranes. It also exhibited excellent anti-protein fouling performance. Therefore, the prepared TiO2@GO/PAN membrane has important practical applications in the field of protein separation. Full article
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