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Showing papers on "Membrane published in 2015"


Journal ArticleDOI
TL;DR: Nanofiltration (NF) membranes have come a long way since it was first introduced during the late 80's as mentioned in this paper, and significant development has taken place in terms of the fundamental understanding of the transport mechanism in NF membranes, which has been translated into predictive modeling based on the modified extended Nernst-Planck equation.

1,374 citations


Journal ArticleDOI
19 Jun 2015-Science
TL;DR: Thin, crumpled polymer films on ceramic supports are high-flux membranes for removing small molecules from organic fluids and were sufficiently rigid that the crumpling textures could withstand pressurized filtration, resulting in increased permeable area.
Abstract: Membranes with unprecedented solvent permeance and high retention of dissolved solutes are needed to reduce the energy consumed by separations in organic liquids We used controlled interfacial polymerization to form free-standing polyamide nanofilms less than 10 nanometers in thickness, and incorporated them as separating layers in composite membranes Manipulation of nanofilm morphology by control of interfacial reaction conditions enabled the creation of smooth or crumpled textures; the nanofilms were sufficiently rigid that the crumpled textures could withstand pressurized filtration, resulting in increased permeable area Composite membranes comprising crumpled nanofilms on alumina supports provided high retention of solutes, with acetonitrile permeances up to 112 liters per square meter per hour per bar This is more than two orders of magnitude higher than permeances of commercially available membranes with equivalent solute retention

1,327 citations


Journal ArticleDOI
TL;DR: In this paper, the authors highlight the recent development of advanced membrane technology such as surface modification, addition of inorganic particles in polymer membrane and the development of ceramic membranes and discuss the effect of operating parameters on the membrane performance.

933 citations


Journal ArticleDOI
TL;DR: This tutorial review aims to present the latest groundbreaking advances in both the theoretical and experimental chemical science and engineering of graphene-based membranes, including their design, fabrication and application.
Abstract: Graphene is a well-known two-dimensional material that exhibits preeminent electrical, mechanical and thermal properties owing to its unique one-atom-thick structure. Graphene and its derivatives (e.g., graphene oxide) have become emerging nano-building blocks for separation membranes featuring distinct laminar structures and tunable physicochemical properties. Extraordinary molecular separation properties for purifying water and gases have been demonstrated by graphene-based membranes, which have attracted a huge surge of interest during the past few years. This tutorial review aims to present the latest groundbreaking advances in both the theoretical and experimental chemical science and engineering of graphene-based membranes, including their design, fabrication and application. Special attention will be given to the progresses in processing graphene and its derivatives into separation membranes with three distinct forms: a porous graphene layer, assembled graphene laminates and graphene-based composites. Moreover, critical views on separation mechanisms within graphene-based membranes will be provided based on discussing the effect of inter-layer nanochannels, defects/pores and functional groups on molecular transport. Furthermore, the separation performance of graphene-based membranes applied in pressure filtration, pervaporation and gas separation will be summarized. This article is expected to provide a compact source of relevant and timely information and will be of great interest to all chemists, physicists, materials scientists, engineers and students entering or already working in the field of graphene-based membranes and functional films.

884 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarized the recent scientific and technological advances in the development of nanocomposite membranes for water treatment and discussed challenges and future research directions in developing high performance nanocomposition membranes.

822 citations


Journal ArticleDOI
TL;DR: A comprehensive method for building membrane containing systems, characterized by simplicity and versatility, and a survey of properties for a large range of lipids as a start of a computational lipidomics project.
Abstract: For simulations of membranes and membrane proteins, the generation of the lipid bilayer is a critical step in the setup of the system. Membranes comprising multiple components pose a particular challenge, because the relative abundances need to be controlled and the equilibration of the system may take several microseconds. Here we present a comprehensive method for building membrane containing systems, characterized by simplicity and versatility. The program uses preset, coarse-grain lipid templates to build the membrane, and also allows on-the-fly generation of simple lipid types by specifying the headgroup, linker, and lipid tails on the command line. The resulting models can be equilibrated, after which a relaxed atomistic model can be obtained by reverse transformation. For multicomponent membranes, this provides an efficient means for generating equilibrated atomistic models. The method is called insane, an acronym for INSert membrANE. The program has been made available, together with the complemen...

776 citations


Journal ArticleDOI
TL;DR: Self-healing hydrophobic light- to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to- Heat conversion material of polypyrrole onto a porous stainless-steel mesh, followed by hydrophilic fluoroalkylsilane modification.
Abstract: Self-healing hydrophobic light-to-heat conversion membranes for interfacial solar heating are fabricated by deposition of light-to-heat conversion material of polypyrrole onto a porous stainless-steel mesh, followed by hydrophobic fluoroalkylsilane modification. The mesh-based membranes spontaneously stay at the water-air interface, collect and convert solar light into heat, and locally heat only the water surface for enhanced evaporation.

775 citations


Journal ArticleDOI
TL;DR: The findings show that neat GO membranes do, indeed, readily disintegrate in water, but the films become stable if they are crosslinked by multivalent cationic metal contaminants.
Abstract: Graphene oxide (GO) films are known to be highly stable in water and this property has made their use in membrane applications in solution possible. However, this state of affairs is somewhat counterintuitive because GO sheets become negatively charged on hydration and the membrane should disintegrate owing to electrostatic repulsion. We have now discovered a long-overlooked reason behind this apparent contradiction. Our findings show that neat GO membranes do, indeed, readily disintegrate in water, but the films become stable if they are crosslinked by multivalent cationic metal contaminants. Such metal contaminants can be introduced unintentionally during the synthesis and processing of GO, most notably on filtration with anodized aluminium oxide filter discs that corrode to release significant amounts of aluminium ions. This finding has wide implications in interpreting the processing-structure-property relationships of GO and other lamellar membranes. We also discuss strategies to avoid and mitigate metal contamination and demonstrate that this effect can be exploited to synthesize new membrane materials.

760 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a review on the preparation and application of electrospun nanofiber membranes as the barrier layer for water treatment, with emphasis on the reinforcement and post-treatment of electro-spun polymer membranes.

742 citations


Journal ArticleDOI
TL;DR: Micrometer-thick MXene membranes demonstrated ultrafast water flux of 37.4 L/(Bar·h·m(2)) and differential sieving of salts depending on both the hydration radius and charge of the ions.
Abstract: Nanometer-thin sheets of 2D Ti3C2Tx (MXene) have been assembled into freestanding or supported membranes for the charge- and size-selective rejection of ions and molecules. MXene membranes with controllable thicknesses ranging from hundreds of nanometers to several micrometers exhibited flexibility, high mechanical strength, hydrophilic surfaces, and electrical conductivity that render them promising for separation applications. Micrometer-thick MXene membranes demonstrated ultrafast water flux of 37.4 L/(Bar·h·m2) and differential sieving of salts depending on both the hydration radius and charge of the ions. Cations with a larger charge and hydration radii smaller than the interlayer spacing of MXene (∼6 A) demonstrate an order of magnitude slower permeation compared to single-charged cations. Our findings may open a door for developing efficient and highly selective separation membranes from 2D carbides.

661 citations


Journal ArticleDOI
TL;DR: It is shown, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate.
Abstract: Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60 A(2). Water flux is found to be two to five orders of magnitude greater than that of other known nanoporous membranes. Pore chemistry is shown to play a significant role in modulating the water flux. Pores with only molybdenum atoms on their edges lead to higher fluxes, which are ∼ 70% greater than that of graphene nanopores. These observations are explained by permeation coefficients, energy barriers, water density and velocity distributions in the pores.

Journal ArticleDOI
TL;DR: This review attempts to give the readers insights into the difficulties of incorporating inorganic nanomaterials into the organic PA layer whose thickness usually falls in a range of several-hundred nanometers and shows new possible approaches to overcome these challenges in TFN membrane fabrication.

Journal ArticleDOI
TL;DR: Benefiting from the exceptional chemical stability of the UiO-66 material, no degradation of membrane performance was observed for various tests up to 170 h toward a wide range of saline solutions, and the high separation performance combined with its outstanding water stability suggests the developed Ui O-66 membrane as a promising candidate for water desalination.
Abstract: In this study, continuous zirconium(IV)-based metal–organic framework (Zr-MOF) membranes were prepared. The pure-phase Zr-MOF (i.e., UiO-66) polycrystalline membranes were fabricated on alumina hollow fibers using an in situ solvothermal synthesis method. Single-gas permeation and ion rejection tests were carried out to confirm membrane integrity and functionality. The membrane exhibited excellent multivalent ion rejection (e.g., 86.3% for Ca2+, 98.0% for Mg2+, and 99.3% for Al3+) on the basis of size exclusion with moderate permeance (0.14 L m–2 h–1 bar–1) and good permeability (0.28 L m–2 h–1 bar–1 μm). Benefiting from the exceptional chemical stability of the UiO-66 material, no degradation of membrane performance was observed for various tests up to 170 h toward a wide range of saline solutions. The high separation performance combined with its outstanding water stability suggests the developed UiO-66 membrane as a promising candidate for water desalination.

Journal ArticleDOI
TL;DR: The latest developments in zeolite membranes are reviewed, with an emphasis on the synthesis techniques, including seed assembly and secondary growth methods, and the latest advancements in MOF and mixed matrix membranes are highlighted.
Abstract: The latest developments in zeolite membranes are reviewed, with an emphasis on the synthesis techniques, including seed assembly and secondary growth methods. This review also discusses the current industrial applications of zeolite membranes, the feasibility of their use in membrane reactors and their hydrothermal stability. Finally, zeolite membranes are compared with metal–organic framework (MOF) membranes and the latest advancements in MOF and mixed matrix membranes are highlighted.

Journal ArticleDOI
TL;DR: It is likely that limitations in fluid mechanics and mass transfer will define the upper bounds of membrane performance, with RO remaining as the key to desalination and reclamation, with other membrane processes growing in support and in niche areas.
Abstract: Membrane technology offers the best options to "drought proof" mankind on an increasingly thirsty planet by purifying seawater or used (waste) water. Although desalination by reverse osmosis (RO) and wastewater treatment by membrane bioreactors are well established the various membrane technologies still need to be significantly improved in terms of separation properties, energy demand and costs. We can now define the ideal characteristics of membranes and advances in material science and novel chemistries are leading to increasingly effective membranes. However developments in membranes must be matched by improved device design and membrane engineering. It is likely that limitations in fluid mechanics and mass transfer will define the upper bounds of membrane performance. Nevertheless major advances and growth over the next 20 years can be anticipated with RO remaining as the key to desalination and reclamation, with other membrane processes growing in support and in niche areas.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the alkaline stability of 26 different quaternary ammonium groups (QA) for temperatures up to 160 °C and NaOH concentrations up to 10 mol L(-1) with the aim to provide a basis for the selection of functional groups for hydroxide exchange membranes in alkaline fuel cells and of ionic-liquid cations stable in basic conditions.
Abstract: The alkaline stability of 26 different quaternary ammonium groups (QA) is investigated for temperatures up to 160 °C and NaOH concentrations up to 10 mol L(-1) with the aim to provide a basis for the selection of functional groups for hydroxide exchange membranes in alkaline fuel cells and of ionic-liquid cations stable in basic conditions. Most QAs exhibit unexpectedly high alkaline stability with the exception of aromatic cations. β-Protons are found to be far less susceptible to nucleophilic attack than previously suggested, whereas the presence of benzyl groups, nearby hetero-atoms, or other electron-withdrawing species promote degradation reactions significantly. Cyclic QAs proved to be exceptionally stable, with the piperidine-based 6-azonia-spiro[5.5]undecane featuring the highest half-life at the chosen conditions. Absolute and relative stabilities presented herein stand in contrast to literature data, the differences being ascribed to solvent effects on degradation.

Journal ArticleDOI
TL;DR: In this paper, a review of different fabrication and modification strategies for various innovative graphene oxide-assisted desalination membranes, including freestanding GO membranes, GO-surface modified membranes and casted GO-incorporated membranes, is presented.

Journal ArticleDOI
TL;DR: In this article, the authors present an overview on fabrication and properties of low-biofouling composite membranes for pressure-driven membrane processes. And they discuss the main objectives for the development of composite membrane for bio-foul mitigation.

Journal ArticleDOI
24 Jul 2015-Science
TL;DR: Two similar ER integral membrane proteins, oxysterol-binding protein (OSBP)–related protein 5 (ORP5) and ORP8, tethered the ER to the plasma membrane (PM) via the interaction of their pleckstrin homology domains with phosphatidylinositol 4-phosphate (PI4P) in this membrane.
Abstract: Lipid transfer between cell membrane bilayers at contacts between the endoplasmic reticulum (ER) and other membranes help to maintain membrane lipid homeostasis. We found that two similar ER integral membrane proteins, oxysterol-binding protein (OSBP)–related protein 5 (ORP5) and ORP8, tethered the ER to the plasma membrane (PM) via the interaction of their pleckstrin homology domains with phosphatidylinositol 4-phosphate (PI4P) in this membrane. Their OSBP-related domains (ORDs) harbored either PI4P or phosphatidylserine (PS) and exchanged these lipids between bilayers. Gain- and loss-of-function experiments showed that ORP5 and ORP8 could mediate PI4P/PS countertransport between the ER and the PM, thus delivering PI4P to the ER-localized PI4P phosphatase Sac1 for degradation and PS from the ER to the PM. This exchange helps to control plasma membrane PI4P levels and selectively enrich PS in the PM.

Journal ArticleDOI
TL;DR: Results indicate that incorporation of GO into a PA membrane can effectively enhance its hydrophilicity and consequently improve its flux and antifouling properties and provides an effective way to develop high performance NF membranes with greater stability.
Abstract: Organic–inorganic hybrid materials are considered the most promising candidates in the preparation of nanofiltration (NF) membranes. The incorporation of nano-particles in a polymer matrix has provided a new approach for the preparation of membranes with enhanced permeability, high selectivity and improved anti-fouling properties. In this study, polyamide (PA) nanofiltration (NF) membranes embedded with various graphene oxide (GO) contents to improve the membrane flux and anti-fouling properties are proposed and successfully prepared for desalination applications. The prepared PA/GO membranes exhibited much higher flux than did pristine PA membranes. A twelve-fold increase in water flux, with a negligible change in salt rejection, was observed after incorporating GO (0.2 wt%) in the PA membrane. Addition of GO also provided a significant improvement in the anti-fouling property of the membrane due to an increase in the hydrophilicity of the membrane. These results indicate that incorporation of GO into a PA membrane can effectively enhance its hydrophilicity and consequently improve its flux and antifouling properties. Because no deleterious effect on the performance of the PA membrane was observed from this modification, this concept provides an effective way to develop high performance NF membranes with greater stability.

Journal ArticleDOI
TL;DR: In this article, a thin-film composite (TFC) membrane with graphene oxide (GO) embedded in its polyamide (PA) layer exhibited high water permeability, anti-biofouling property, and chlorine resistance without loss of salt rejection.

Journal ArticleDOI
TL;DR: Freestanding ultrathin rGO membranes, with thicknesses down to 17 nm, are fabricated via a facile approach using hydroiodic acid vapor and water-assisted delamination, providing the potential for addressing the key challenge that limits the performance of current forward osmosis membranes.
Abstract: Freestanding ultrathin rGO membranes, with thicknesses down to 17 nm, are fabricated via a facile approach using hydroiodic acid vapor and water-assisted delamination. These unique membranes provide the potential for addressing the key challenge that limits the performance of current forward osmosis membranes.

Journal ArticleDOI
TL;DR: In this article, the authors have reviewed several alternatives for the fabrication and evaluation of polymer electrolyte and composite membranes for fuel cell applications, including hybrid organic-inorganic composite membrane.

Journal ArticleDOI
TL;DR: A facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes are reported that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery.
Abstract: Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries.

Journal ArticleDOI
TL;DR: The performance of solution exfoliated MoS2 thin flexible membranes as supercapacitor electrodes in a symmetrical coin cell arrangement using an aqueous electrolyte (Na2SO4) demonstrates a simple and scalable application of layered 2D materials toward electrochemical energy storage.
Abstract: Two-dimensional materials, such as graphene and molybdenum disulfide (MoS2), can greatly increase the performance of electrochemical energy storage devices because of the combination of high surface area and electrical conductivity. Here, we have investigated the performance of solution exfoliated MoS2 thin flexible membranes as supercapacitor electrodes in a symmetrical coin cell arrangement using an aqueous electrolyte (Na2SO4). By adding highly conductive graphene to form nanocomposite membranes, it was possible to increase the specific capacitance by reducing the resistivity of the electrode and altering the morphology of the membrane. With continued charge/discharge cycles the performance of the membranes was found to increase significantly (up to 800%), because of partial re-exfoliation of the layered material with continued ion intercalation, as well as increasing the specific capacitance through intercalation pseudocapacitance. These results demonstrate a simple and scalable application of layered...

Journal ArticleDOI
TL;DR: In this article, a novel thin film nanocomposite reverse osmosis (TFN-RO) membrane was prepared by interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC) monomers and embedding reduced graphene oxide (rGO)/TiO 2 nanocompositionite in its polyamide layer.

Journal ArticleDOI
TL;DR: Core-shell nanoparticles with lipid shells and varying water content and rigidity but with the same chemical composition, size, and surface properties are assembled using a microfluidic platform to alter the cellular uptake efficiency.
Abstract: Core-shell nanoparticles (NPs) with lipid shells and varying water content and rigidity but with the same chemical composition, size, and surface properties are assembled using a microfluidic platform. Rigidity can dramatically alter the cellular uptake efficiency, with more-rigid NPs able to pass more easily through cell membranes. The mechanism accounting for this rigidity-dependent cellular uptake is revealed through atomistic-level simulations.

Journal ArticleDOI
TL;DR: This review regarding mussel-inspired chemistry in the surface engineering of polymer membranes and a further perspective of the mussels-inspired catecholamine in membrane science and technology is given.

Journal ArticleDOI
TL;DR: In this paper, a hydrophobic, hydrothermally stable metal-organic framework (MOF) was successfully incorporated into the selective polyamide (PA) layer of thin-film nanocomposite (TFN) membranes for water desalination.

Journal ArticleDOI
TL;DR: Results from sonication experiments and positron annihilation spectroscopy confirmed that EDA cross-linking not only enhanced structural stability but also enlarged the nanochannels among the laminated GO nanosheets for higher water permeability.
Abstract: A novel dual-modification strategy, including (1) the cross-linking and construction of a GO framework by ethylenediamine (EDA) and (2) the amine-enrichment modification by hyperbranched polyethylenimine (HPEI), has been proposed to design stable and highly charged GO framework membranes with the GO selective layer thickness of 70 nm for effective heave metal removal via nanofiltration (NF). Results from sonication experiments and positron annihilation spectroscopy confirmed that EDA cross-linking not only enhanced structural stability but also enlarged the nanochannels among the laminated GO nanosheets for higher water permeability. HPEI 60K was found to be the most effective post-treatment agent that resulted in GO framework membranes with a higher surface charge and lower transport resistance. The newly developed membrane exhibited a high pure water permeability of 5.01 L m–2 h–1 bar–1 and comparably high rejections toward Mg2+, Pb2+, Ni2+, Cd2+, and Zn2+. These results have demonstrated the great pote...