Single-walled carbon nanotube gutter layer supported ultrathin zwitterionic microporous polymer membrane for high-performance lithium-sulfur battery.

Development of efficient lithium-sulfur (Li-S) battery requires the need to develop an appropriate functional separator that allows strong facilitation and transport of lithium ions together with limited passage of polysulfides. In this work, a multifunctional separator (TB-BAA/SWCNT/PP) is developed through spin coating of a novel zwitterionic microporous polymer (TB-BAA) on the gutter layer constructed from single-walled carbon nanotubes (SWCNT), where commercially available polypropylene (PP) separator is used to act as the mechanical support. SWCNT in this study serves as the first modification layer to decrease the size of the macropores in the PP separator, while the ultrathin TB-BAA top barrier layer with the presence of zwitterionic side chains allows the creation of confined ionic channels with both lithiophilic and sulfophilic groups.

Zwitterionic covalent organic framework as a multifunctional sulfur host toward durable lithium-sulfur batteries.

The shuttle effect and slow redox kinetics of sulfur cathode are the most significant technical challenges to the practical application of lithium-sulfur (Li-S) battery. Herein, a novel zwitterionic covalent organic framework (ZW-COF) wrapped onto carbon nanotubes (CNTs), labeled as ZW-COF@CNT, is developed by a reversible condensation reaction of 1,3,5-benzenetricarboxaldehyde (BTA) and 3,8-diamino-6-phenylphenanthridine (DPPD) with CNTs as a template and a subsequently-one-step post-synthetic grafting reaction with 1,3-propanesultone. The experimental results showed that, after loading active material sulfur, zwitterionic ZW-COF@CNT can effectively suppress the shuttle effect of the soluble lithium polysulfides (LiPSs) in Li-S batteries, and exhibits better cycling behavior than the as-developed neutral COF@CNT.

Membranes for Gas Separation and Purification Processes.

This Special Issue, entitled "Membranes for Gas Separation and Purification Processes", was introduced to discuss the recent progress in the development of membranes for gas separation and purification [...

Recent Advances in Mixed-Matrix Membranes for Light Hydrocarbon (C-C) Separation.

Light hydrocarbons, obtained through the petroleum refining process, are used in numerous applications. The separation of the various light hydrocarbons is challenging and expensive due to their similar melting and boiling points. Alternative methods have been investigated to supplement cryogenic distillation, which is energy intensive.

Emerging Materials for Mixed-Matrix Membranes.

This Special Issue, entitled "Emerging Materials for Mixed-Matrix Membranes" was introduced to cover the recent progress in the development of materials for mixed-matrix membranes (MMMs) with potential application in fields such as sea water desalination, gas separation, pharmaceutical separation, wastewater treatment and the removal of pathogenic (viruses and bacteria) microorganisms as well as solvents and resource recovery [...

Recent Progress in Mixed-Matrix Membranes for Hydrogen Separation.

Membrane separation is a compelling technology for hydrogen separation. Among the different types of membranes used to date, the mixed-matrix membranes (MMMs) are one of the most widely used approaches for enhancing separation performances and surpassing the Robeson upper bound limits for polymeric membranes. In this review, we focus on the recent progress in MMMs for hydrogen separation.

Enhanced Performance of Carbon Molecular Sieve Membranes Incorporating Zeolite Nanocrystals for Air Separation.

Three different zeolite nanocrystals (SAPO-34, PS-MFI and ETS-10) were incorporated into the polymer matrix (Matrimid 5218) as polymer precursors, with the aim of fabricating mixed-matrix carbon molecular sieve membranes (CMSMs). These membranes are investigated for their potential for air separation process. Based on our gas permeation results, incorporating porous materials is feasible to improve O permeability, owing to the creation of additional porosities in the resulting mixed-matrix CMSMs.

Carbon Molecular Sieve Membranes Comprising Graphene Oxides and Porous Carbon for CO/N Separation.

To improve the CO/N separation performance, mixed-matrix carbon molecular sieve membranes (mixed-matrix CMSMs) were fabricated and tested. Two carbon-based fillers, graphene oxide (GO) and activated carbon (YP-50F), were separately incorporated into two polymer precursors (Matrimid 5218 and ODPA-TMPDA), and the resulting CMSMs demonstrated improved CO permeability. The improvement afforded by YP-50F was more substantial due to its higher accessible surface area.

Graphene-based Membranes for H Separation: Recent Progress and Future Perspective.

Hydrogen (H) is an industrial gas that has showcased its importance in several well-known processes such as ammonia, methanol and steel productions, as well as in petrochemical industries. Besides, there is a growing interest in H production and purification owing to the global efforts to minimize the emission of greenhouse gases. Nevertheless, H which is produced synthetically is expected to contain other impurities and unreacted substituents (e.

CO/N Separation Properties of Polyimide-Based Mixed-Matrix Membranes Comprising UiO-66 with Various Functionalities.

Nanocrystalline UiO-66 and its derivatives (containing -NH, -Br, -(OH)) were developed via pre-synthetic functionalization and incorporated into a polyimide membrane to develop a mixed-matrix membrane (MMM) for CO/N separation. Incorporation of the non-functionalized UiO-66 nanocrystals into the polyimide membrane successfully improved CO permeability, with a slight decrease in CO/N selectivity, owing to its large accessible surface area. The addition of other functional groups further improved the CO/N selectivity of the polymeric membrane, with UiO-66-NH, UiO-66-Br, and UiO-66-(OH) demonstrating improvements of 12%, 4%, and 17%, respectively.

MXene Materials for Designing Advanced Separation Membranes.

MXenes are emerging rapidly as a new family of multifunctional nanomaterials with prospective applications rivaling that of graphenes. Herein, a timely account of the design and performance evaluation of MXene-based membranes is provided. First, the preparation and physicochemical characteristics of MXenes are outlined, with a focus on exfoliation, dispersion stability, and processability, which are crucial factors for membrane fabrication.

Enhanced O/N Separation of Mixed-Matrix Membrane Filled with Pluronic-Compatibilized Cobalt Phthalocyanine Particles.

Membrane-based air separation (O/N) is of great importance owing to its energy efficiency as compared to conventional processes. Currently, dense polymeric membranes serve as the main pillar of industrial processes used for the generation of O- and N-enriched gas. However, conventional polymeric membranes often fail to meet the selectivity needs owing to the similarity in the effective diameters of O and N gases.

Leveraging Nanocrystal HKUST-1 in Mixed-Matrix Membranes for Ethylene/Ethane Separation.

The energy-intensive ethylene/ethane separation process is a key challenge to the petrochemical industry. HKUST-1, a metal-organic framework (MOF) which possesses high accessible surface area and porosity, is utilized in mixed-matrix membrane fabrication to investigate its potential for improving the performance for CH/CH separation. Prior to membrane fabrication and gas permeation analysis, nanocrystal HKUST-1 was first synthesized.

Hierarchically Porous Co-MOF-74 Hollow Nanorods for Enhanced Dynamic CO Separation.

Metal-organic frameworks (MOFs) with coordinatively unsaturated (open) metal sites have been intensively investigated in gas separations because their active sites can selectively interact with targeted molecules such as CO. Although such MOFs have shown to exhibit exceptional CO uptake capacity at equilibrium, the dynamic separation behavior is often not satisfactory to be considered in practical applications. Herein, we report a facile and efficient self-sacrifice template strategy based on the nanoscale Kirkendall effect to form novel Co-MOF-74 hollow nanorods enabling adsorption/desorption of gas molecules in a facilitated manner.

Harnessing Filler Materials for Enhancing Biogas Separation Membranes.

Biogas is an increasingly attractive renewable resource, envisioned to secure future energy demands and help curb global climate change. To capitalize on this resource, membrane processes and state-of-the-art membranes must efficiently recover methane (CH) from biogas by separating carbon dioxide (CO). Composite (a.

Separation of Acetylene from Carbon Dioxide and Ethylene by a Water-Stable Microporous Metal-Organic Framework with Aligned Imidazolium Groups inside the Channels.

Separation of acetylene from carbon dioxide and ethylene is challenging in view of their similar sizes and physical properties. Metal-organic frameworks (MOFs) in general are strong candidates for these separations owing to the presence of functional pore surfaces that can selectively capture a specific target molecule. Here, we report a novel 3D microporous cationic framework named JCM-1.