Development Of Composite Membranes Research Articles

Development of Hollow Fiber Membranes Functionalized with Ionic Liquids for Enhanced CO2 Separation.

The combination of CO2-selective ionic liquids (ILs) with block copolymers, such as Pebax 1657, has demonstrated an enhancement of the gas separation capabilities of polymeric membranes. In the current work, the development of composite membranes by applying a thin, concentrated selective layer made of Pebax/imidazolium-based ionic liquids (ILs) is presented. The objective of the experiments was to determine the optimized IL loading and investigate how the alteration of the anion impacts the properties of the membranes. Two membrane configurations have been studied: coated flat sheet membranes, supported on a porous poly(ether sulfone) (PES) layer, as well as composite hollow fiber membranes, supported on commercial polypropylene (PP) hollow fibers. Coated hollow fiber composites were fabricated using a continuous coating method, offering a straightforward scalability in the manufacturing process. The determined mechanical pressure stability of hollow fiber composites reached up to 5 bar, indicating their potential for various industrial gas separation applications. It was found that the Pebax 1657-based coating containing 40 wt % [C6mim][NTf2] yielded membranes with the best gas separation properties, for both the coated flat sheet and the hollow fiber configurations. The CO2 permeance of hollow fibers reached 23.29 GPU, whereas the CO2/N2 ideal selectivity stood at 8.7, suggesting the necessity of the further enhancement of the coating technique, which can be achieved, for example, through application of multiple coatings. Nonetheless, the superior ideal selectivity of the CO2/CO separation, reaching 12.44, gave a promising outlook for further novel membrane applications, which involve the separation of the aforementioned gases.

Towards durable Li-hybrid flow batteries: composite membrane development, cell performance, and perspective

Fabrication temperature and filler distribution significantly impact the Li+ selectivity of polymer–ceramic membranes. Along with catholyte and design issues, overcoming membrane-related problems is essential for prototyping Li-hybrid flow batteries.

Osmium Nanoparticles-Polypropylene Hollow Fiber Membranes Applied in Redox Processes.

Composite membranes play a very important role in the separation, concentration, and purification processes, but especially in membrane reactors and membrane bioreactors. The development of composite membranes has gained momentum especially through the involvement of various nanoparticles, polymeric, oxide, or metal, that have contributed to increasing their reactivity and selectivity. This paper presents the preparation and characterization of an active metal nanoparticle-support polymer type composite membrane, based on osmium nanoparticles obtained in situ on a polypropylene hollow fiber membrane. Osmium nanoparticles are generated from a solution of osmium tetroxide in tert-butyl alcohol by reduction with molecular hydrogen in a contactor with a polypropylene membrane. The composite osmium-polypropylene hollow fiber obtained membranes (Os-PPM) were characterized from the morphological and structural points of view: scanning electron microscopy (SEM), high resolution SEM (HR-SEM), energy dispersive spectroscopy analysis (EDAX), X-ray diffraction analysis (XRD), Fourier transform Infrared (FTIR) spectroscopy, thermal gravimetric analysis, and differential scanning calorimetry (TGA, DSC). The process performance was tested in a redox process of p-nitrophenol and 10-undecylenic (10-undecenoic) acid, as a target substance of biological or biomedical interest, in solutions of lower aliphatic alcohols in a membrane contactor with a prepared composite membrane. The characteristics of osmium nanoparticles-polypropylene hollow fiber membranes open the way to biological and biotechnological applications. These membranes do not contaminate the working environment, operate at relatively low temperatures, provide a large contact area between reactants, allow successive oxidation and reduction operations in the same module, and help to recover the reaction mass by ultrafiltration. The results obtained show that the osmium-polypropylene composite membrane allows the reduction of p-nitrophenol or the oxidation of 10-undecylenic acid, the conversion depending on the concentration in the lower aliphatic alcohol, the nature of the lower aliphatic alcohol, and the oxidant or reducing flow through the membrane contactor.

Development of composite membranes with irregular rod-like structure via atom transfer radical polymerization for efficient oil-water emulsion separation

Development of superhydrophilic, stable and cost-effective composite membranes for efficient oil-water emulsion separation is highly desirable. Herein, an irregular rod-like composite membrane was prepared through 3-aminopropyltriethoxysilane (APTES) modification, followed by acrylamide polymerization with atomic transfer radical polymerization (ATRP). The as-prepared membrane exhibits superhydrophilicity/underwater superoleophobicity due to its irregular rod-like structure and pores-induced capillary actions. The composite membrane has demonstrated sufficient stability in acidic, alkaline and salty environments due to the polymerization of acrylamide. Moreover, the as-prepared composite membrane has effectively separated various oil-water emulsions and demonstrated high permeation and superior flux recovery. The present work demonstrates that the ATRP-assisted composite membrane is a promising material in a wide range of applications, such as industrial wastewater recovery and drinking water treatment.

Graphite coating on alumina substrate for the fabrication of hydrogen selective membranes

Development of composite membranes is a suitable alternative to improve the hydrogen flux through palladium membranes. The porous substrate should not represent a barrier to gas permeation, but the roughness of its surface should be sufficiently smooth for the deposition of a thin and defect-free metal layer. In this study, the performances of the modification of the outer surface of an asymmetric alumina hollow fibre substrate by the deposition of a graphite layer were evaluated. The roughness of the substrate outer surface was reduced from 120 to 37 nm after graphite coating. After graphite coating, the hydrogen permeance through the composite membrane produced with 2 Pd plating cycles was of 1.02 × 10−3 mol s−1 m−2 kPa−1 at 450 °C and with infinite H2/N2 selectivity. Similar hydrogen permeance was obtained with the composite membrane without graphite coating, also at infinite H2/N2 selectivity, but 3 Pd plating cycles were necessary. Thus, graphite coating on asymmetric alumina hollow fibres is a suitable alternative to reduce the required palladium amount to produce hydrogen selective membranes.

Development of composite membrane PBAT: Zeolite Y for application as rhynchophorol release system

ABSTRACTComposite membranes consisting of biodegradable poly(butylene adipate‐co‐terephthalate (PBAT) and zeolite Y (0–10 wt %) were produced by extrusion. Zeolite Y is well dispersed in the membrane up to 5 wt %, but tends to agglomerate at higher contents. The presence of zeolite Y in the composite resulted in an improvement of the thermal stability, mechanical properties, and increased the barrier properties. The interaction of the composite membranes with rhynchophorol was investigated by different techniques, showing that the semiochemical progressively lixiviates PBAT monomers, causing thermal and mechanical properties to decrease. However, no interaction seemed to occur between the rhynchophorol and the zeolite. Studies of diffusion of pheromone through membranes have shown that the addition of the zeolite Y has not contributed significantly to a decrease in the release rate of rhynchophorol, but the presence of the zeolite Y helps to increase chemical, mechanical, and thermal stabilities of the membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45757.

(Ce,Gd)O2−δ-based dual phase membranes for oxygen separation

Composite membranes based on selected combinations of the ionic conductor Ce0.9Gd0.1O1.95 (CGO) and electronic/mixed conductors (Ag–CuO, LaCoO3 (LC), La0.6Sr0.4CoO3−δ (LSC), La0.6Sr0.4FeO3−δ (LSF), (La0.6Sr0.4)0.99Co0.2Fe0.8O3−δ (LSCF), and La0.75Sr0.25Cr0.97V0.03O3−δ (LSCrV)) were prepared and characterized with respect to sinterability, oxygen permeation rate, phase interaction, and microstructure. These factors are important when considering the development of composite membranes with CGO as the oxide ion conducting phase. Composite membranes with relative densities >91% were fabricated using conventional powder mixing and sintering or in the case of CGO/Ag–CuO with liquid metal infiltration. Oxygen permeation fluxes across the composite membrane disks were measured as a function of temperature with air on the feed side and varying N2/air mixtures on the permeate side. No chemical reaction between CGO and the other materials were detected by X-ray diffraction. The highest flux of 1.53×10−7molcm−2s−1 (0.21Nmlcm−2min−1) at 800°C under N2/air was obtained for a CGO/LSC composite with a thickness of ca. 1mm. The oxygen flux of the CGO/LSC membrane exhibited no degradation after 300h of operation. The results indicate a promising prospect for further tailoring and optimization of CGO-based composites for application in oxygen separation.

Novel polysulfone–spray-dried silica composite membrane for water purification: Preparation, characterization and performance evaluation

Development of composite membrane using organic polymer and inorganic nanoparticles is an emerging field of water purification process. Here we report the preparation, characterization and performance of a novel composite polymeric membrane prepared using composite of spray dried silica granule and polysulfone. We investigate the structure and performance of the membranes prepared using N-methyl-2-pyrrolidone or N,N-dimethyl formamide as solvent for the composite material. Such polymer-nanocomposite membrane shows significant enhancement of water permeability without sacrificing for the separation performance. In order to establish the structure–function correlation, we probed the mesoscopic structure of polymer casting solution and final membranes using small-angle scattering, atomic force microscopy and contact angle measurements. We put forward a plausible mechanism in support of the enhanced performance of the composite membranes.

Development of Composite Membranes as Selective Adsorbent for Yttrium Ion

Development of Composite Membranes as Selective Adsorbent for Yttrium Ion

Improved direct methanol fuel cell performance of layer-by-layer assembled composite and catalyst containing membranes

The development of composite membranes and catalyst containing membranes (CCMs) with low methanol permittivity attracts a great deal of research attention for achieving higher performance in direct methanol fuel cells (DMFCs). Here, the fabrication and DMFC performance of composite and catalyst containing membranes (CCM) via layer-by-layer (lbl) technique are demonstrated. lbl composite and catalyst containing membrane based membrane-electrode assemblies (MEAs) show quite impressive cell performance. While the single cell performances of lbl composite membrane based MEAs are found to be in the range of 19.5 and 22mWcm−2, DMFC performance of MEA obtained from Pt containing self-assembled 10 bilayer of polyallylamine hydrochloride and polyvinylsulfonic acid, (PAH/PVS-H+)10-Pt, is found to be 24mWcm−2. This performance is nearly 65.5% higher compared to pure Nafion®112 based MEA. Inductive coupling plasma-mass spectroscopy (ICP-MS) result shows that Pt particles incorporate inside lbl multilayers with a loading of 0.28μgcm−2. From the analyses of the performance evaluations, it is emphasized that the use of thin lbl catalyst containing membranes can be possible and quite promising in DMFC applications instead of thicker membranes due to their improved methanol barrier properties as well as proton conductivity.

Seawater Reverse Osmosis (SWRO) desalination by thin-film composite membrane—Current development, challenges and future prospects

Since the breakthrough discovery made by Cadotte and his co-workers in the 1970s, thin-film composite (TFC) membrane prepared using interfacial polymerization (IP) technique has experienced significant progress in composite membrane development and emerged as one of the most advanced technologies in water and wastewater purification processes. Nowadays, the most promising technology to desalinate seawater is reverse osmosis (RO), which is driven by a pressure gradient across a semi-permeable membrane. This technology has drawn great attention mainly due to its relatively low energy usage during operation as well as easy of operation and maintenance compared to other conventional technologies such as thermal desalination. On the basis of the brief introduction on TFC membrane, this paper will highlight the recent developments of RO TFC membrane and its challenges in seawater desalination process with respect to fouling problem, boron rejection and chlorine attack. Future directions in SWRO membrane research are also discussed to further expand research and development related to seawater desalination process.

Synthesis and characterization of chitosan-polyvinyl alcohol-bioactive glass hybrid membranes

The tissue engineering strategy is a new approach for the regeneration of cementum, which is essential for the regeneration of the periodontal tissue. This strategy involves the cell cultures present in this tissue, called cementoblasts, and located on an appropriate substrate for posterior implantation in the regeneration site. Prior studies from our research group have shown that the proliferation and viability of cementoblasts increase in the presence of the ionic dissolution products of bioactive glass particles. Therefore, one possible approach to obtaining adequate substrates for cementoblast cultures is the development of composite membranes containing bioactive glass. In the present study, composite films of chitosan-polyvinyl alcohol-bioactive glass containing different glass contents were developed. Glutaraldehyde was also added to allow for the formation of cross-links and changes in the degradation rate. The glass phase was introduced in the material by a sol-gel route, leading to an organic-inorganic hybrid. The films were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Bioactivity tests were also conducted by immersion of the films in simulated body fluid (SBF). Films containing up to 30% glass phase could be obtained. The formation of calcium phosphate was observed after the immersion of the films. A calcium phosphate layer formed more quickly on materials containing higher bioactive glass contents. In the hybrid containing 23% bioactive glass, a complete layer was formed after 24 h immersion, showing the high bioactivity of this material. However, despite the higher in vitro bioactivity, the film with 23% glass showed lower mechanical properties compared with films containing up to 17% glass.

Polyamide thin-film composite membranes prepared by interfacial polymerization for pervaporation separation

Pervaporation is an important membraneprocess in chemical industries in which valuablesare isolated from the liquid mixture. Dehydrationof alcohols and other organic solvents is a well-known example for pervaporation process. Poly-amides have been studied as one of suitablemembrane materials because of their high ther-mal stability, excellent mechanical strength andhigh resistance to organic solvents. Polyamidesshow high selectivity in dehydration of alcohol atwide range of water concentrations. However, itshows low permeation flux because of the lowerfree volume and low solubility of water. In orderto improve the permeation flux of polyamidemembranes without sacrific ing the selectivity, themembrane morphology must be converted from adense thick symmetric membrane to an asymmet-ric or composite type morphology. The develop-ment of composite membranes is one of the keyfactors for successful application of polyamidemembranes in many areas. The composite membrane with the poly-amide thin layer can be prepared by interfacialpolymerization. Many researchers have focusedtheir attention on the reverse osmosis [1] andnanofiltration separation processes [2] by usingthe thin-film composite membranes. However,there are few reports on investigating the per-vaporation of polyamide thin-film compositemembranes [3]. In addition, the interfacial poly-merization technique is an adequate method forthe preparation method of the composite mem-brane with ultrathin and dense polyamide skinlayer. Maybe it can improve the permeation rateand maintain the selectivity. Therefore, in thisstudy, the polyamide thin-film composite mem-branes were prepared by the interfacial polymer-ization of triethylenetetramine (TETA) andtrimesoyl chloride (TMC) onto the surface ofasymmetric polyacrylonitrile (PAN) membranesto be utilized in the pervaporation of the aque-

Composite Membranes for Medium-Temperature PEM Fuel Cells

▪ Abstract The main obstacles to greater commercialization of polymer electrolyte fuel cells are mostly related to the low-proton conductivity at low-relative humidity of the known ionomeric membranes, to their high methanol permeability and poor mechanical properties above ∼130°C. A possible solution for these problems has been found in the development of composite membranes, where particles of suitable fillers are dispersed in the ionomer matrix. The preparation methods for obtaining composite membranes are described, and recent work dealing with composite ionomeric membranes containing silica, heteropolyacids, layered metal phosphates, and phosphonates is reviewed. Finally, new strategies for the preparation of nano-composite membranes and for the filling of porous polymeric membranes with highly conductive zirconium phosphonates are described. The expected influence of size and orientation of these particles on membrane properties, such as conductivity and permeability to methanol, is also discussed.

Prediction of skin permeability of drugs. II. Development of composite membrane as a skin alternative

Artificial composite membranes composed of silicone and pHEMA (poly(2-hydroxyethyl methacrylate)) were developed as an alternative for skin membranes. The structure of the composite membranes was designed based on a model simulation of drug permeation properties. Composite membrane permeabilities for a wide range of drugs with diverse physicochemical properties were measured and compared with those of excised hairless rat skin. A reasonable correlation was found between the calculated and observed permeability coefficients, and between the observed values for the composite and excised skin membranes. It is suggested that human skin permeability of drugs may be predicted by using slightly modified composite membranes.