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Sample records for liquid membrane esplim

  1. Supported liquid membrane electrochemical separators

    DOEpatents

    Pemsler, J. Paul; Dempsey, Michael D.

    1986-01-01

    Supported liquid membrane separators improve the flexibility, efficiency and service life of electrochemical cells for a variety of applications. In the field of electrochemical storage, an alkaline secondary battery with improved service life is described in which a supported liquid membrane is interposed between the positive and negative electrodes. The supported liquid membranes of this invention can be used in energy production and storage systems, electrosynthesis systems, and in systems for the electrowinning and electrorefining of metals.

  2. Liquid membrane purification of biogas

    SciTech Connect

    Majumdar, S.; Guha, A.K.; Lee, Y.T.; Papadopoulos, T.; Khare, S. . Dept. of Chemistry and Chemical Engineering)

    1991-03-01

    Conventional gas purification technologies are highly energy intensive. They are not suitable for economic removal of CO{sub 2} from methane obtained in biogas due to the small scale of gas production. Membrane separation techniques on the other hand are ideally suited for low gas production rate applications due to their modular nature. Although liquid membranes possess a high species permeability and selectivity, they have not been used for industrial applications due to the problems of membrane stability, membrane flooding and poor operational flexibility, etc. A new hollow-fiber-contained liquid membrane (HFCLM) technique has been developed recently. This technique overcomes the shortcomings of the traditional immobilized liquid membrane technology. A new technique uses two sets of hydrophobic, microporous hollow fine fibers, packed tightly in a permeator shell. The inter-fiber space is filled with an aqueous liquid acting as the membrane. The feed gas mixture is separated by selective permeation of a species through the liquid from one fiber set to the other. The second fiber set carries a sweep stream, gas or liquid, or simply the permeated gas stream. The objectives (which were met) of the present investigation were as follows. To study the selective removal of CO{sub 2} from a model biogas mixture containing 40% CO{sub 2} (the rest being N{sub 2} or CH{sub 4}) using a HFCLM permeator under various operating modes that include sweep gas, sweep liquid, vacuum and conventional permeation; to develop a mathematical model for each mode of operation; to build a large-scale purification loop and large-scale permeators for model biogas separation and to show stable performance over a period of one month.

  3. Arsenic Removal by Liquid Membranes

    PubMed Central

    Marino, Tiziana; Figoli, Alberto

    2015-01-01

    Water contamination with harmful arsenic compounds represents one of the most serious calamities of the last two centuries. Natural occurrence of the toxic metal has been revealed recently for 21 countries worldwide; the risk of arsenic intoxication is particularly high in Bangladesh and India but recently also Europe is facing similar problem. Liquid membranes (LMs) look like a promising alternative to the existing removal processes, showing numerous advantages in terms of energy consumption, efficiency, selectivity, and operational costs. The development of different LM configurations has been a matter of investigation by several researching groups, especially for the removal of As(III) and As(V) from aqueous solutions. Most of these LM systems are based on the use of phosphine oxides as carriers, when the metal removal is from sulfuric acid media. Particularly promising for water treatment is the hollow fiber supported liquid membrane (HFSLM) configuration, which offers high selectivity, easy transport of the targeted metal ions, large surface area, and non-stop flow process. The choice of organic extractant(s) plays an essential role in the efficiency of the arsenic removal. Emulsion liquid membrane (ELM) systems have not been extensively investigated so far, although encouraging results have started to appear in the literature. For such LM configuration, the most relevant step toward efficiency is the choice of the surfactant type and its concentration. PMID:25826756

  4. Method of fabrication of supported liquid membranes

    DOEpatents

    Luebke, David R.; Hong, Lei; Myers, Christina R.

    2015-11-17

    Method for the fabrication of a supported liquid membrane having a dense layer in contact with a porous layer, and a membrane liquid layer within the interconnected pores of the porous layer. The dense layer is comprised of a solidified material having an average pore size less than or equal to about 0.1 nanometer, while the porous layer is comprised of a plurality of interconnected pores and has an average pore size greater than 10 nanometers. The supported liquid membrane is fabricated through the preparation of a casting solution of a membrane liquid and a volatile solvent. A pressure difference is established across the dense layer and porous layer, the casting solution is applied to the porous layer, and the low viscosity casting solution is drawn toward the dense layer. The volatile solvent is evaporated and the membrane liquid precipitates, generating a membrane liquid layer in close proximity to the dense layer.

  5. Membrane separation of ionic liquid solutions

    DOEpatents

    Campos, Daniel; Feiring, Andrew Edward; Majumdar, Sudipto; Nemser, Stuart

    2015-09-01

    A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

  6. Separation of metals by supported liquid membranes

    SciTech Connect

    Takigawa, D.Y.

    1990-12-31

    A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.

  7. Separation of metals by supported liquid membrane

    DOEpatents

    Takigawa, Doreen Y.

    1992-01-01

    A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.

  8. Supported polymeric liquid membranes for wastewater treatment

    SciTech Connect

    Ho, S.V.

    1997-12-31

    The removal or elimination of organic residues from aqueous waste streams represents a major need in the chemical industry. A class of membrane has been developed called supported polymeric liquid membranes capable of removing and concentrating low molecular weight organic compounds from dilute aqueous solutions, especially those that also contain high concentrations of inorganic salts. These membranes are prepared by filling the pores of microfiltration or ultrafiltration membranes with polymeric (oligomeric) liquids having affinity for the organic compounds of interest. With this approach, membrane`s separation characteristics are decoupled from its mechanical stability and depend primarily on the chemical properties of the liquid polymer used. As a result, membranes of diverse separation capabilities can be conveniently prepared using liquid polymers possessing the appropriate functional groups. Physical properties typical of polymeric liquids such as high viscosity, extremely low volatility and insolubility in water contribute to the observed stability of the membranes under broad operating conditions. This membrane process has been successfully applied to several aqueous waste streams. This paper describes the early development activities for treating a waste stream containing a dilute mixture of C2-C6 carboxylic acids. Feasibility testings were initially carried out with flat sheet membranes in a small stirred cell. Scaleup was then conducted using hollow fiber membranes, first with small modules prepared in the laboratory, then with a much larger commercial module. Attractive features of this membrane process include the ability to recover the contaminants in concentrated form for either recycle or more economical disposal, low pressure (ambient) operation, simple scale-up using commercial hollow fiber modules, and ease of in-situ regeneration of the polymeric liquid.

  9. Separations by supported liquid membrane cascades

    DOEpatents

    Danesi, Pier R.

    1986-01-01

    The invention describes a new separation technique which leads to multi-stage operations by the use of a series (a cascade) of alternated carrier-containing supported-liquid membranes. The membranes contain alternatively a liquid cation exchanger extractant and a liquid anion exchanger extractant (or a neutral extractant) as carrier. The membranes are spaced between alternated aqueous electrolytic solutions of different composition which alternatively provide positively charged extractable species and negatively charged (or zero charged) extractable species, of the chemical species to be separated. The alternated aqueous electrolytic solutions in addition to providing the driving force to the process, simultaneously function as a stripping solution from one type of membrane and as an extraction-promoting solution for the other type of membrane. The aqueous electrolytic solutions and the supported liquid membranes are arranged in such a way to provide a continuous process which leads to the continuous enrichment of the species which show the highest permeability coefficients. By virtue of the very high number of stages which can be arranged, even chemical species having very similar chemical behavior (and consequently very similar permeability coefficients) can be completely separated. The invention also provide a way to concentrate the separated species.

  10. Membrane technologies for liquid radioactive waste treatment

    NASA Astrophysics Data System (ADS)

    Chmielewski, A. G.; Harasimowicz, M.; Zakrzewska-Trznadel, G.

    1999-01-01

    The paper deals with some problems concerning reduction of radioactivity of liquid low-level nuclear waste streams (LLLW). The membrane processes as ultrafiltration (UF), seeded ultrafiltration (SUF), reverse osmosis (RO) and membrane distillation (MD) were examined. Ultrafiltration enables the removal of particles with molecular weight above cut-off of UF membranes and can be only used as a pre-treatment stage. The improvement of removal is achieved by SUF, employing macromolecular ligands binding radioactive ions. The reduction of radioactivity in LLLW to very low level were achieved with RO membranes. The results of experiments led the authors to the design and construction of UF+2RO pilot plant. The development of membrane distillation improve the selectivity of membrane process in some cases. The possibility of utilisation of waste heat from cooling system of nuclear reactors as a preferable energy source can significantly reduce the cost of operation.

  11. Membranes Remove Metal Ions Fron Industrial Liquids

    NASA Technical Reports Server (NTRS)

    Hsu, W. P. L.; May, C.

    1983-01-01

    Use of membrane films affords convenient and economical alternative for removing and recovering metal cations present in low concentrations from large quantities of liquid solutions. Possible applications of membrane films include use in analytical chemistry for determination of small amounts of toxic metallic impurities in lakes, streams, and municipal effluents. Also suitable for use as absorber of certain pollutant gases and odors present in confined areas.

  12. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    In this project we well evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated. (VC)

  13. Metal ion separations by supported liquid membranes

    SciTech Connect

    Gyves, J. de; San Miguel, E.R. de

    1999-06-01

    Carrier-mediated transport through supported liquid membranes is currently recognized as a potentially valuable technology for selective separation and concentration of toxic and valuable metal ions. In this paper, a review of the fundamental aspects concerning metal ion transport and the influencing factors are surveyed in terms of data modeling, membrane efficiency (permeability, selectivity, stability), and data acquisition and evaluation. An account of the information reviewed demonstrates the need for critical reflection on system performances in order to accomplish scaling up operations. On the same basis, an attempt to outline some future trends in the field is presented.

  14. Liquid Droplets on a Highly Deformable Membrane

    NASA Astrophysics Data System (ADS)

    Schulman, Rafael; Dalnoki-Veress, Kari

    2015-11-01

    We present measurements of the deformation produced by micro-droplets atop thin elastomeric and glassy free-standing films. Due to the Laplace pressure, the droplets deform the elastic membrane thereby forming a bulge. Thus, there are two angles that define the droplet/membrane geometry: the angle the liquid surface makes with the film and the angle the deformed bulge makes with the film. The contact line geometry is well captured by a Neumann construction which includes contributions from interfacial and mechanical tensions. Finally, we show that a droplet atop a film with biaxial tension assumes an equilibrium shape which is elongated along the axis of high tension.

  15. Liquid immiscibility in model bilayer lipid membranes

    NASA Astrophysics Data System (ADS)

    Veatch, Sarah L.

    There is growing evidence that cell plasma membranes are laterally organized into "raft" regions in which particular lipids and proteins are concentrated. These domains have sub-micron dimensions and have been implicated in vital cell functions. Similar liquid domains are observed in model bilayer membrane mixtures that mimick cellular lipid compositions. In model membranes, domains can be large (microns) and can readily form in the absence of proteins. This thesis presents studies of liquid immiscibility in model membrane systems using two experimental methods. By fluorescence microscopy, this thesis documents that miscibility transitions occur in a wide variety of ternary lipid mixtures containing high melting temperature (saturated) lipids, low melting temperature (usually unsaturated) lipids, and cholesterol. I have constructed detailed miscibility phase diagrams for three separate ternary lipid mixtures (DOPC/DPPC/Chol, DOPC/PSM/Chol, and POPC/PSM/Chol). Phase separation is also observed in membranes of lipids extracted from human erythrocytes. NMR experiments probe lipid order and verify the coexistence of a saturated lipid and cholesterol rich liquid ordered (Lo) phase with a more disordered, unsaturated lipid rich liquid crystalline (Lalpha) phase at low temperatures. These experiments also find multiple thermodynamic transitions and lipid organization on different length-scales. This complexity is revealed because fluorescence microscopy and NMR probe lipid order at different length-scales (>1mum vs. ˜100nm). NMR detects small domains (˜80nm) at temperatures just below the miscibility transition, even though micron-scale domains are observed by fluorescent microscopy. NMR does detect large-scale ("100nm) demixing, but at a lower temperature. In addition, it has long been known that >10nm length-scale structure is present in many lipid mixtures containing cholesterol and at least one additional lipid species, though it is shown here that only a subset of

  16. Liquid separation by a graphene membrane

    NASA Astrophysics Data System (ADS)

    Fileti, E. E.; Dalpian, G. M.; Rivelino, R.

    2010-12-01

    The behavior of liquids separated by a single graphene membrane has been studied with extensive molecular dynamics (MD) simulations at ambient conditions. With the help of appropriate empirical potentials, we have exploited two liquid phases forming distinct systems; say XGY, where G stands for graphene and X (Y) represents water (W), benzene (B), or acetonitrile (A). Our MD simulations revealed important changes in the wettability patterns of these liquids near the graphene surface. For instance, WGW exhibits strong density oscillations in a thin interfacial region with thickness of ˜2.4 nm. In the case of BGB and AGA the oscillating-density interfacial region extends beyond ˜3 nm and ˜5 nm, respectively, under ambient conditions. More interestingly, our findings indicate that a liquid at one side of the graphene sheet can affect the degree of wetting on the other side, by means of dispersion interactions through the graphene membrane. These systems can offer a useful framework to understand the structural as well as thermodynamic properties of interfaces by considering a real two-dimensional substrate.

  17. Analytical Applications of Transport Through Bulk Liquid Membranes.

    PubMed

    Diaconu, Ioana; Ruse, Elena; Aboul-Enein, Hassan Y; Bunaciu, Andrei A

    2016-07-03

    This review discusses the results of research in the use of bulk liquid membranes in separation processes and preconcentration for analytical purposes. It includes some theoretical aspects, definitions, types of liquid membranes, and transport mechanism, as well as advantages of using liquid membranes in laboratory studies. These concepts are necessary to understand fundamental principles of liquid membrane transport. Due to the multiple advantages of liquid membranes several studies present analytical applications of the transport through liquid membranes in separation or preconcentration processes of metallic cations and some organic compounds, such as phenol and phenolic derivatives, organic acids, amino acids, carbohydrates, and drugs. This review presents coupled techniques such as separation through the liquid membrane coupled with flow injection analysis.

  18. Ionic Liquid Membranes for Carbon Dioxide Separation

    SciTech Connect

    Myers, C.R.; Ilconich, J.B.; Luebke, D.R.; Pennline, H.W.

    2008-07-12

    Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while with the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on

  19. Transport through liquid membranes containing omeprazole and lansoprazole.

    PubMed

    Nagappa, A N; Pandi, P V; Mishra, P K; Girish, Rahul K; Shanmukh, I

    2002-12-01

    Omeprazole and lansoprazole, the therapeutically important drugs belonging to proton pump inhibitor category are extensively used in the treatment of gastric ulcers. Transport through liquid membranes generated by these drugs in lecithin-cholesterol mixture in series with a supporting membrane has been studied. The data obtained show the formation of liquid membrane in series with the supporting membrane. Transport of cations, chloride and bicarbonate ions in the presence liquid membranes generated by omeprazole and lanzoprazole indicate the modification in the permeability of various permeants.

  20. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  1. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will also be investigated.

  2. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-01-01

    In this project we intend to study a novel process concept, i.e, the use of ceramic membranes reactors in upgrading of coal derived liquids. Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. They have, furthermore, the inherent capability for combining reaction and separation in a single step. Thus they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, as those typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sol-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  3. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-01-01

    In this project we intend to study a novel process concept, i.e.,the use of ceramic membranes reactors in upgrading of coal derived liquids. Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. They have, furthermore, the inherent capability for combining reaction and separation in a single step. Thus they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, as those typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we wig evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  4. Rejuvenation of Spent Media via Supported Emulsion Liquid Membranes

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    2002-01-01

    The overall goal of this project was to maximize the reuseability of spent fermentation media. Supported emulsion liquid membrane separation, a highly efficient extraction technique, was used to remove inhibitory byproducts during fermentation; thus, improve the yield while reducing the need for fresh water. The key objectives of this study were: (1) Develop an emulsion liquid membrane system targeting low molecular weight organic acids which has minimal toxicity on a variety of microbial systems. (2) Conduct mass transfer studies to allow proper modeling and design of a supported emulsion liquid membrane system. (3) Investigate the effect of gravity on emulsion coalescence within the membrane unit. (4) Access the effect of water re-use on fermentation yields in a model microbial system. and (5) Develop a perfusion-type fermentor utilizing a supported emulsion liquid membrane system to control inhibitory fermentation byproducts (not completed due to lack of funds)

  5. Liquid membrane coated ion-exchange column solids

    DOEpatents

    Barkey, Dale P.

    1988-01-01

    This invention relates to a method for improving the performance of liquid membrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selective for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

  6. Liquid separation by membrane pervaporation: A review

    SciTech Connect

    Feng, X.; Huang, R.Y.M.

    1997-04-01

    Pervaporation is one of the most active areas in membrane research, and the pervaporation process has been shown to be an indispensable component for chemical separations. In this paper, the recent development in pervaporation membranes and pervaporation processes is reviewed, and some outstanding questions involved in membrane pervaporation are discussed with emphasis on the following issues: mass transport in the membrane, membrane material selection, concentration polarization in the boundary layer, pressure buildup in hollow fiber membranes, asymmetric and composite membranes, and the activation energy for permeation. The authors attempt to provide insight into this dynamic field and to highlight some of the outstanding problems yet to be solved or clarified. 150 refs.

  7. Development of Practical Supported Ionic Liquid Membranes: A Systematic Approach

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-11-01

    Supported liquid membranes (SLMs) are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties to optimize membrane performance. These membranes also have the advantage of liquid phase diffusivities, which are higher than those observed in polymers and grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which may possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they are stable at elevated temperatures and have negligible vapor pressure. A study has been conducted evaluating the use of a variety of ionic liquids in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated membrane performance for the resulting materials. Several steps have been taken in the development of practical supported ionic liquid membranes. Proof-of-concept was established by showing that ionic liquids could be used as the transport media in SLMs. Results showed that ionic liquids are suitable media for gas transport, but the preferred polymeric supports were not stable at temperatures above 135oC. The use of cross-linked nylon66 supports was found to produce membranes mechanically stable at temperatures exceeding 300oC but CO2/H2 selectivity was poor. An ionic liquid whose selectivity does not decrease with increasing temperature was needed, and a functionalized ionic liquid that complexes with CO2 was used. An increase in CO2/H2 selectivity with increasing temperature over the range of 37 to 85oC was observed and the dominance of a

  8. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-04-01

    Supported liquid membranes are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties as a direct guide in the development of a capture technology. These membranes also have the advantage of liquid phase diffusivities higher than those observed in polymeric membranes which grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high carbon dioxide solubility relative to light gases such as hydrogen, are an excellent candidate for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of several ionic liquids, including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide, 1-butyl-3-methyl-imidazolium nitrate, and 1-ethyl-3-methyl-imidazolium sulfate in supported ionic liquid membranes for the capture of carbon dioxide from streams containing hydrogen. In a joint project, researchers at the University of Notre Dame lent expertise in ionic liquid synthesis and characterization, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Initial results have been very promising with carbon dioxide permeabilities as high as 950 barrers and significant improvements in carbon dioxide/hydrogen selectivity over conventional polymers at 37C and at elevated temperatures. Results include a comparison of the performance of several ionic liquids and a number of supports as well as a discussion of innovative fabrication techniques currently under development.

  9. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-01-01

    Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. Having the inherent capability for combining reaction and separation in a single step, they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, such as these typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. This project will evaluate the performance of Sol-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. Development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  10. Membrane permeation process for dehydration of organic liquid mixtures using sulfonated ion-exchange polyalkene membranes

    DOEpatents

    Cabasso, Israel; Korngold, Emmanuel

    1988-01-01

    A membrane permeation process for dehydrating a mixture of organic liquids, such as alcohols or close boiling, heat sensitive mixtures. The process comprises causing a component of the mixture to selectively sorb into one side of sulfonated ion-exchange polyalkene (e.g., polyethylene) membranes and selectively diffuse or flow therethrough, and then desorbing the component into a gas or liquid phase on the other side of the membranes.

  11. Liquid membrane coated ion-exchange column solids

    DOEpatents

    Barkey, Dale P.

    1989-01-01

    This invention relates to a method for improving the performance of liquid embrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selected for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

  12. Polyacrylate membranes for tunable liquid-filled microlenses

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Zappe, Hans; Seifert, Andreas

    2013-04-01

    We present the use of polyacrylate membranes for the fabrication of pneumatically actuated variable lenses. Whereas the most commonly used membrane material for tunable liquid-filled lenses is polydimethylsiloxane (PDMS), polyacrylate membranes have the advantages of high resistance to swelling in silicone oil and enhanced compatibility with a wide range of aqueous optical liquids. These features are quantitatively demonstrated by comparing the material properties and performance of PDMS and polyacrylate membrane lenses. The optical transparency of polyacrylate is more than 92%. The surface roughness is below 3.3 nm rms, and reversible elastic deformation could be demonstrated. Optical measurements show that the cutoff frequency of the modulation transfer function of polyacrylate lenses with different liquid fillings, using a reference contrast of 0.2, is more than 1.5 times larger than that of the same system assembled with PDMS membranes filled with water.

  13. Extraction of molybdenum by a supported liquid membrane method.

    PubMed

    Basualto, Carlos; Marchese, José; Valenzuela, Fernando; Acosta, Adolfo

    2003-04-10

    This is a report on the extraction of molybdenum(VI) ions using a supported liquid membrane, prepared by dissolving in kerosene, the extractant Alamine 336 (a long-chain tertiary amine) employed as mobile carrier. A flat hydrophobic microporous membrane was utilised as solid support. Appropriate conditions for Mo(VI) extraction through the liquid membrane were obtained from the results of liquid-liquid extraction and stripping partition experiments. The influence of feed solution acidity, the carrier extractant concentration in the organic liquid film and the content of strip agent on the metal flux through membrane were investigated. It was established that maximal extraction of metal is achieved at a pH 2.0 if sulphuric acid is used in the feed solution and at a pH value over 11.0 if Na(2)CO(3) is used as strip agent. Moreover, the molybdenum extraction through membrane is enhanced when a 0.02 mol l(-1) content of the amine carrier in the organic phase is used. The present paper deals with an equilibrium investigation of the extraction of Mo(VI) by Alamine 336 and its permeation conditions through the liquid membrane, and examines a possible mechanism of extraction.

  14. Deashing of coal liquids with ceramic membrane microfiltration and diafiltration

    SciTech Connect

    Bishop, B.; Goldsmith, R.

    1995-12-31

    Removal of mineral matter from liquid hydrocarbons derived from the direct liquefaction of coal is required for product acceptability. Current methods include critical solvent deashing (Rose{sup {reg_sign}} process from Kerr-McGee) and filtration (U.S. Filter leaf filter as used by British Coal). These methods produce ash reject streams containing up to 15% of the liquid hydrocarbon product. Consequently, CeraMem proposed the use of low cost, ceramic crossflow membranes for the filtration of coal liquids bottoms to remove mineral matter and subsequent diafiltration (analogous to cake washing in dead-ended filtration) for the removal of coal liquid from the solids stream. The use of these ceramic crossflow membranes overcomes the limitations of traditional polymeric crossflow membranes by having the ability to operate at elevated temperature and to withstand prolonged exposure to hydrocarbon and solvent media. In addition, CeraMem`s membrane filters are significantly less expensive than competitive ceramic membranes due to their unique construction. With these ceramic membrane filters, it may be possible to reduce the product losses associated with traditional deashing processes at an economically attractive cost. The performance of these ceramic membrane microfilters is discussed.

  15. Novel macrocyclic carriers for proton-coupled liquid membrane transport

    SciTech Connect

    Lamb, J.D.

    1991-06-10

    The objective of our research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period, including selenium-containing macrocycles, new crown-4 structures, and several new crown structures containing nitrogen based heterocycles as substituents in the principal macrocyclic ring. The cation binding properties of these macrocycles were investigated by potentiometric titration, calorimetric titration, solvent extraction, and NMR techniques. In addition, hydrophobic macrocycles were incorporated into dual hollow fiber membrane systems to investigate their membrane performance, especially in the proton-coupled transport mode. It was found that the dual hollow fiber system maintains the cation selectivity and permeability of supported liquid membranes, while enhancing membrane stability. The diffusion limited transport model was expanded to account for membrane solvent effects. Furthermore, Eu{sup 2+} transport was found to be similar to that of strontium and much higher than that of the lanthanides, in supported liquid membrane systems.

  16. Boron removal in radioactive liquid waste by forward osmosis membrane

    SciTech Connect

    Doo Seong Hwang; Hei Min Choi; Kune Woo Lee; Jei Kwon Moon

    2013-07-01

    This study investigated the treatment of boric acid contained in liquid radioactive waste using a forward osmosis membrane. The boron permeation through the membrane depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7 and increases with an increase of the osmotic driving force. The boron flux decreases slightly with the salt concentration, but is not heavily influenced by a low salt concentration. The boron flux increases linearly with the concentration of boron. No element except for boron was permeated through the FO membrane in the multi-component system. The maximum boron flux is obtained in an active layer facing a draw solution orientation of the CTA-ES membrane under conditions of less than pH 7 and high osmotic pressure. (authors)

  17. Supported liquid inorganic membranes for nuclear waste separation

    DOEpatents

    Bhave, Ramesh R; DeBusk, Melanie M; DelCul, Guillermo D; Delmau, Laetitia H; Narula, Chaitanya K

    2015-04-07

    A system and method for the extraction of americium from radioactive waste solutions. The method includes the transfer of highly oxidized americium from an acidic aqueous feed solution through an immobilized liquid membrane to an organic receiving solvent, for example tributyl phosphate. The immobilized liquid membrane includes porous support and separating layers loaded with tributyl phosphate. The extracted solution is subsequently stripped of americium and recycled at the immobilized liquid membrane as neat tributyl phosphate for the continuous extraction of americium. The sequestered americium can be used as a nuclear fuel, a nuclear fuel component or a radiation source, and the remaining constituent elements in the aqueous feed solution can be stored in glassified waste forms substantially free of americium.

  18. Prospects for using membrane distallation for reprocessing liquid radioactive wastes

    SciTech Connect

    Dytnerskii, Y.I.; Karlin, Y.V.; Kropotov, B.N.

    1994-05-01

    Membrane distillation is a promising method for deep desalinization and for removal of impurities of different nature from water. The crux of the method is as follows. The initial (hot) solution, heated up to 30-70{degrees}C, is fed into one side of a hydrophobic microporous membrane. A less heated (cold) distillate moves along the other. Since the membrane is hydrophobic and the pores are small ({approximately}1 {mu}m and less), the liquid phase does not penetrate into the pores in accordance with Kelvin`s law. The vapor evaporating from the surface of the hot solution (the evaporation surface in this case are solution meniscuses forming at the entrance into a pore) penetrates into the pores of the membrane, diffuses through the air layer in the pore, and condenses on the surface of the menisci of cold liquid. In the process rarefaction is produced in the pores, and this accelerates evaporation and therefore increases its efficiency.

  19. Rejuvenation of Spent Media via Supported Emulsion Liquid Membranes

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    2002-01-01

    The overall goal of this project is to maximize the reuseability of spent fermentation media. Supported emulsion liquid membrane separation, a highly efficient extraction technique, is used to remove inhibitory byproducts during fermentation; thus, improving the yield while reducing the need for fresh water. The key objectives of this study are: Develop an emulsion liquid membrane system targeting low molecular weight organic acids which has minimal toxicity on a variety of microbial systems; Conduct mass transfer studies to allow proper modeling and design of a supported emulsion liquid membrane system; Investigate the effect of gravity on emulsion coalescence within the membrane unit; Access the effect of water re-use on fermentation yields in a model microbial system; Develop a perfusion-type fermentor utilizing a supported emulsion liquid membrane system to control inhibitory fermentation byproducts; Work for the coming year will focus on the determination of toxicity of various solvents, selection of the emulsifying agents, as well as characterizing the mass transfer of hollow-fiber contactors.

  20. Removal of pesticides from aqueous solutions using liquid membrane emulsions

    SciTech Connect

    Norwood, V.M. III.

    1991-01-01

    Extractive liquid membrane technology is based on a water-in-oil emulsion as the vehicle to effect separation. An aqueous internal reagent phase is emulsified into an organic phase containing a surfactant and optional complexing agents. The emulsion, presenting a large membrane surface area, is then dispersed in an aqueous continuous phase containing the species to be removed. The desired species is transferred from the continuous, phase through the organic liquid membrane and concentrated in the internal reagent phase. Extraction and stripping occur simultaneously rather than sequentially as in conventional solvent extraction. Experiments were conducted to assess the feasibility of using liquid membranes to extract pesticides from rinsewaters typical of those generated by fertilizer/agrichemical dealers. A liquid membrane emulsion containing 10% NaOH as the internal reagent phase was used to extract herbicides from aqueous solution at a continuous phase:emulsion ratio of 5:1. Removals of 2,4-D, MCPA, Carbaryl, Diazinon, and Atrazine were investigated.

  1. Removal of pesticides from aqueous solutions using liquid membrane emulsions

    SciTech Connect

    Norwood, V.M. III

    1991-12-31

    Extractive liquid membrane technology is based on a water-in-oil emulsion as the vehicle to effect separation. An aqueous internal reagent phase is emulsified into an organic phase containing a surfactant and optional complexing agents. The emulsion, presenting a large membrane surface area, is then dispersed in an aqueous continuous phase containing the species to be removed. The desired species is transferred from the continuous, phase through the organic liquid membrane and concentrated in the internal reagent phase. Extraction and stripping occur simultaneously rather than sequentially as in conventional solvent extraction. Experiments were conducted to assess the feasibility of using liquid membranes to extract pesticides from rinsewaters typical of those generated by fertilizer/agrichemical dealers. A liquid membrane emulsion containing 10% NaOH as the internal reagent phase was used to extract herbicides from aqueous solution at a continuous phase:emulsion ratio of 5:1. Removals of 2,4-D, MCPA, Carbaryl, Diazinon, and Atrazine were investigated.

  2. Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes.

    PubMed

    Zeh, Matthew; Wickramanayake, Shan; Hopkinson, David

    2016-03-23

    Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid(®) and Torlon(®) as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C₆mim][Tf₂N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse.

  3. Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

    PubMed Central

    Zeh, Matthew; Wickramanayake, Shan; Hopkinson, David

    2016-01-01

    Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse. PMID:27023620

  4. Secondary and lyotropic liquid crystal membranes for improved aqueous separations

    NASA Astrophysics Data System (ADS)

    Nemade, Parag Ramesh

    An effective membrane separation process should have high flux (i.e., volume filtered per unit membrane surface area per unit time) and selectivity (i.e., passage of the desired species and rejection of undesired species). This dissertation examined two approaches, secondary membranes and lyotropic liquid crystal membranes, for improving flux and selectivity in aqueous liquid separations. The first part of my work emphasizes the use of pre-deposited secondary membranes and backflushing for controlling membrane fouling in microfiltration and ultrafiltration of biological mixtures. Use of secondary membranes increased the permeate flux in microfiltration by several fold. Protein transmission is also enhanced due to the presence of the secondary membrane, and the amount of protein recovered is more than twice that obtained during filtration of protein-only solutions under otherwise identical conditions. In ultrafiltration, the flux enhancement due to secondary membranes is 50%, or less. For the second part of my research, I developed and evaluated polymerized lyotropic liquid crystal (LLC) thin-film composite membranes. LLC assemblies provide an opportunity to make nanoporous polymer membranes with precise control over chemical and structural features on the nanometer scale, which is currently lacking in commercial reverse osmosis (RO) and nanofiltration (NF) membranes available today. These LLC composite membranes are prepared by photopolymerization of solution-cast films of LLC monomer on an ultrafiltration support membrane. These LLC membranes appeared to exhibit almost linearly increasing ionic rejection based on ionic diameter. LLC monomer was modified to achieve a 15% reduction in channel diameter, through the use of a larger multivalent Eu3+ cation as the carboxylate counterion. However, the monomers synthesized required use of solvents such as tetrahydrofuran, which resulted in the dissolution and damage of the support membranes used. Therefore, this direction

  5. Membrane contactor assisted extraction/reaction process employing ionic liquids

    DOEpatents

    Lin, Yupo J [Naperville, IL; Snyder, Seth W [Lincolnwood, IL

    2012-02-07

    The present invention relates to a functionalized membrane contactor extraction/reaction system and method for extracting target species from multi-phase solutions utilizing ionic liquids. One preferred embodiment of the invented method and system relates to an extraction/reaction system wherein the ionic liquid extraction solutions act as both extraction solutions and reaction mediums, and allow simultaneous separation/reactions not possible with prior art technology.

  6. High Performance Immobilized Liquid Membrane for Carbon Dioxide Separations

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    An immobilized liquid membrane has a substrate. A plurality of capsules is disposed on the substrate. Each of the capsules is permeable to a first gas of a mixture of gases comprising the st gas and a second gas. Each of the capsules is substantially impermeable to the second gas. A liquid is disposed in each of the capsules that is permeable to the first gas and substantially impermeable to the second gas.

  7. Membrane treatment of liquid wastes from radiological decontamination operations.

    PubMed

    Svittsov, A A; Khubetsov, S B; Volchek, K

    2011-01-01

    The paper focuses on the evaluation of membrane filtration for the treatment of liquid radioactive streams generated in area decontamination operations. In this work, semi-permeable membranes were demonstrated to be effective reducing the volume of wastewater containing cesium and cobalt by two orders of a magnitude. The efficiency of membrane separation was enhanced by employing additives that enlarged the size of target radionuclide species and improved their rejection by the membranes. This was achieved by chelation with synthetic water-soluble polymers and by adsorption on micro particles of adsorbent coupled with micelle formation. The effect of wastewater composition and that of the radionuclide-binding additives on the volume reduction was investigated. Membrane treatment is expected to help simplify further processing and decrease disposal costs.

  8. Mechanical equilibrium of thick, hollow, liquid membrane cylinders.

    PubMed Central

    Waugh, R E; Hochmuth, R M

    1987-01-01

    The mechanical equilibrium of bilayer membrane cylinders is analyzed. The analysis is motivated by the observation that mechanically formed membrane strands (tethers) can support significant axial loads and that the tether radius varies inversely with the axial force. Previously, thin shell theory has been used to analyze the tether formation process, but this approach is inadequate for describing and predicting the equilibrium state of the tether itself. In the present work the membrane is modeled as two adjacent, thick, anisotropic liquid shells. The analysis predicts an inverse relationship between axial force and tether radius, which is consistent with experimental observation. The area expansivity modulus and bending stiffness of the tether membrane are calculated using previously measured values of tether radii. These calculated values are consistent with values of membrane properties measured previously. Application of the analysis to precise measurements of the relationship between tether radius and axial force will provide a novel method for determining the mechanical properties of biomembrane. PMID:3651558

  9. Liquid-membrane coupling response of submersible electrostatic acoustic transducer

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Yost, William T.

    1989-01-01

    A mathematical model was developed for the liquid-membrane coupling response of the submersible electrostatic acoustic transducer (ESAT) described by Cantrell et al. (1979). The model accounts for the ESAT's rolloff response and predicts the essential features of the ESAT frequency response. Model predictions were found to agree well with measurements taken over the frequency range from 1 to 11 MHz.

  10. Internal mass transfer in hollow fiber supported liquid membranes

    SciTech Connect

    Urtiaga, A.M.; Irabien, J.A. )

    1993-03-01

    The study of mass transfer in hollow fiber supported liquid membranes is justified by a large number of separation processes. The analysis starts from the definition of an overall permeability coefficient which is a lumped parameter of a particular system and process conditions which gathers both mass transfer and operation parameters. By applying the film theory the contribution of the interfacial mass-transfer coefficient due to the inner boundary layer and the contribution of the supported liquid membrane permeability coefficient can be separated and analyzed. The study yields overall permeability coefficients that can be compared with those expected from hollow fiber design equations suggested earlier. The second approach considers the continuity mass conservation equation and the associated boundary conditions for the solute in the inner fluid. The analysis by means of the fundamental equations separates the effects of the operation variables such as the hydrodynamic conditions and length and diameter of the fibers from the mass-transfer properties of the system, described by the wall Sherwood number. The scope of the present work is to compare both methods of describing a hollow fiber supported liquid membrane module, analyzing the influence of the internal mass transfer on the design of such systems. In the experimental system under consideration, the simultaneous separation-concentration of phenol from aqueous solutions with hollow fiber supported liquid membrane modules is performed. The influence of the flow rate of the inner aqueous phase on the phenol separation rate has been studied.

  11. Membrane-less variable focus liquid lens with manual actuation

    NASA Astrophysics Data System (ADS)

    Patra, Roshan; Agarwal, Shivam; Kondaraju, Sasidhar; Bahga, Supreet Singh

    2017-04-01

    We present a tunable, membrane-less, mechanical-wetting liquid lens that can be actuated manually using a linear actuator such as screw or piston. The operation of the liquid lens is based on deforming the interface separating two immiscible liquids with different refractive indices, while pinning the three-phase contact line at the sharp edge of lens aperture. Our lens design improves upon the existing designs of mechanical-wetting lenses by eliminating the use of complex actuation mechanisms, without compromising on the optical performance. We demonstrate the operation of the liquid lens by tuning its power back and forth from negative to positive by simple rotation of a screw. We also present an analytical description of the focal length of the lens and validate it with detailed experimental measurements. Our experiments show that the focal length of the liquid lens can be tuned repeatably without any adverse effects of hysteresis and gravity.

  12. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T. . Dept. of Chemical Engineering); Liu, P.K.T. ); Webster, I.A. )

    1992-01-01

    Membrane reactors are today finding extensive applications for gas and vapor phase catalytic reactions (see discussion in the introduction and recent reviews by Armor [92], Hsieh [93] and Tsotsis et al. [941]). There have not been any published reports, however, of their use in high pressure and temperature liquid-phase applications. The idea to apply membrane reactor technology to coal liquid upgrading has resulted from a series of experimental investigations by our group of petroleum and coal asphaltene transport through model membranes. Coal liquids contain polycyclic aromatic compounds, which not only present potential difficulties in upgrading, storage and coprocessing, but are also bioactive. Direct coal liquefaction is perceived today as a two-stage process, which involves a first stage of thermal (or catalytic) dissolution of coal, followed by a second stage, in which the resulting products of the first stage are catalytically upgraded. Even in the presence of hydrogen, the oil products of the second stage are thought to equilibrate with the heavier (asphaltenic and preasphaltenic) components found in the feedstream. The possibility exists for this smaller molecular fraction to recondense with the unreacted heavy components and form even heavier undesirable components like char and coke. One way to diminish these regressive reactions is to selectively remove these smaller molecular weight fractions once they are formed and prior to recondensation. This can, at least in principle, be accomplished through the use of high temperature membrane reactors, using ceramic membranes which are permselective for the desired products of the coal liquid upgrading process. An additional incentive to do so is in order to eliminate the further hydrogenation and hydrocracking of liquid products to undesirable light gases.

  13. Polymeric Pseudo-Liquid Membranes from Poly(N-oleylacrylamide)

    PubMed Central

    Shiono, Hiroko; Yoshikawa, Masakazu

    2014-01-01

    A polymeric pseudo-liquid membrane (PPLM) was constructed from poly(N-oleylacrylamide) (PC18AAm), which exhibited a rubbery state under membrane transport conditions and used as the membrane matrix. In the present study, dibenzo-18-crown-6 (DB18C6) and dibenzo-21-crown-7 (DB21C7) were adopted as transporters for alkali metal ions. KCl was adopted as a model substrate for DB18C6 and CsCl the latter. Chiral transporter, O-allyl-N-(9-anthracenylmethyl)cinchonidinium bromide (AAMC) was used as a transporter for chiral separation of a racemic mixture of phenylglycine (Phegly). The l-somer was transported in preference to the antipode. The present study revealed that PPLMs are applicable to membrane transport, such as metal ion transport and chiral separation. PMID:24957173

  14. Membrane-targeting liquid crystal nanoparticles (LCNPs) for drug delivery

    NASA Astrophysics Data System (ADS)

    Nag, Okhil K.; Naciri, Jawad; Spillmann, Christopher M.; Delehanty, James B.

    2016-03-01

    In addition to maintaining the structural integrity of the cell, the plasma membrane regulates multiple important cellular processes, such as endocytosis and trafficking, apoptotic pathways and drug transport. The modulation or tracking of such cellular processes by means of controlled delivery of drugs or imaging agents via nanoscale delivery systems is very attractive. Nanoparticle-mediated delivery systems that mediate long-term residence (e.g., days) and controlled release of the cargoes in the plasma membrane while simultaneously not interfering with regular cellular physiology would be ideal for this purpose. Our laboratory has developed a plasma membrane-targeted liquid crystal nanoparticle (LCNP) formulation that can be loaded with dyes or drugs which can be slowly released from the particle over time. Here we highlight the utility of these nanopreparations for membrane delivery and imaging.

  15. Feasibility of Surfactant-Free Supported Emulsion Liquid Membrane Extraction

    NASA Technical Reports Server (NTRS)

    Hu, Shih-Yao B.; Li, Jin; Wiencek, John M.

    2001-01-01

    Supported emulsion liquid membrane (SELM) is an effective means to conduct liquid-liquid extraction. SELM extraction is particularly attractive for separation tasks in the microgravity environment where density difference between the solvent and the internal phase of the emulsion is inconsequential and a stable dispersion can be maintained without surfactant. In this research, dispersed two-phase flow in SELM extraction is modeled using the Lagrangian method. The results show that SELM extraction process in the microgravity environment can be simulated on earth by matching the density of the solvent and the stripping phase. Feasibility of surfactant-free SELM (SFSELM) extraction is assessed by studying the coalescence behavior of the internal phase in the absence of the surfactant. Although the contacting area between the solvent and the internal phase in SFSELM extraction is significantly less than the area provided by regular emulsion due to drop coalescence, it is comparable to the area provided by a typical hollow-fiber membrane. Thus, the stripping process is highly unlikely to become the rate-limiting step in SFSELM extraction. SFSELM remains an effective way to achieve simultaneous extraction and stripping and is able to eliminate the equilibrium limitation in the typical solvent extraction processes. The SFSELM design is similar to the supported liquid membrane design in some aspects.

  16. Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

    NASA Astrophysics Data System (ADS)

    Hoarfrost, Megan Lane

    Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the addition of an ionic liquid affects the thermodynamic self-assembly of block copolymers, and how the confinement of ionic liquids to block copolymer nanodomains affects their ion-conducting properties is essential for predictable structure-property control. The lyotropic phase behavior of block copolymer/ionic liquid mixtures is shown to be reminiscent of mixtures of block copolymers with selective molecular solvents. A variety of ordered microstructures corresponding to lamellae, hexagonally close-packed cylinders, body-centered cubic, and face-centered cubic oriented micelles are observed in a model system composed of mixtures of imidazolium bis(trifluoromethylsulfonyl)imide ([Im][TFSI]) and poly(styrene- b-2-vinyl pyridine) (PS-b-P2VP). In contrast to block copolymer/molecular solvent mixtures, the interfacial area occupied by each PS-b-P2VP chain decreases upon the addition of [Im][TFSI], indicating a considerable increase in the effective segregation strength of the PS-b-P2VP copolymer with ionic liquid addition. The relationship between membrane structure and ionic conductivity is illuminated through the development of scaling relationships that describe the ionic conductivity of block copolymer/ionic liquid mixtures as a function of membrane composition and temperature. It is shown that the dominant variable influencing conductivity is the overall volume fraction of ionic liquid in the mixture, which means there

  17. Enantioselective separations using chiral supported liquid crystalline membranes.

    PubMed

    Han, Sangil; Rabie, Feras; Marand, Eva; Martin, Stephen M

    2012-07-01

    Porous and nonporous supported liquid crystalline membranes were produced by impregnating porous cellulose nitrate supports with cholesteric liquid crystal (LC) materials consisting of 4-cyano-4'-pentylbiphenyl (5CB) mixed with a cholesterol-based dopant (cholesteryl oleyl carbonate [COC], cholesteryl nonanoate [CN], or cholesteryl chloride [CC]). The membranes exhibit selectivity for R-phenylglycine and R-1-phenylethanol because of increased interactions between the S enantiomers and the left-handed cholesteric phase. The selectivity of both phenylglycine and 1-phenylethanol in 5CB/CN membranes decreases with effective pore diameter while the permeabilities increase, as expected. Phenylglycine, which is insoluble in the LC phase, exhibits no transport in the nonporous (completely filled) membranes; however, 1-phenylethanol, which is soluble in the LC phase, exhibits transport but negligible enantioselectivity. The enantioselectivity for 1-phenylethanol was higher (1.20 in 5CB/COC and 5CB/CN membranes) and the permeability was lower in the cholesteric phase than in the isotropic phase. Enantioselectivity was also higher in the 5CB/COC cholesteric phase than in the nematic phase of undoped 5CB (1.03). Enantioselectivity in the cholesteric phase of 5CB doped with CC (1.1), a dopant lacking hydrogen bonding groups, was lower than in the 5CB/COC phases. Finally, enantioselectivity increases with the dopant concentration up to a plateau value at approximately 17 mol%.

  18. Research News: Emulsion Liquid Membrane Extraction in a Hollow-Fiber Contactor

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.; Hu, Shih-Yao

    2000-01-01

    This article describes how ELMs (emulsion liquid membranes) can be used for extraction. The article addresses the disadvantages of ELM extraction in a stirred contactor, and the advantages of SELMs (supported emulsion liquid membranes). The introduction of the article provides background information on liquid-liquid solvent extraction and dispersion-free solvent extraction.

  19. GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

    SciTech Connect

    Howard S. Meyer

    2003-07-01

    Gas Technology Institute (GTI) is conducting this research program whose objective is to develop gas/liquid membranes for natural gas upgrading to assist DOE in achieving their goal of developing novel methods of upgrading low quality natural gas to meet pipeline specifications. Kvaerner Process Systems (KPS) and W. L. Gore & Associates (GORE) gas/liquid membrane contactors are based on expanded polytetrafluoroethylene (ePTFE) membranes acting as the contacting barrier between the contaminated gas stream and the absorbing liquid. These resilient membranes provide much greater surface area for transfer than other tower internals, with packing densities five to ten times greater, resulting in equipment 50-70% smaller and lower weight for the same treating service. The scope of the research program is to (1) build and install a laboratory- and a field-scale gas/liquid membrane absorber; (2) operate the units with a low quality natural gas feed stream for sufficient time to verify the simulation model of the contactors and to project membrane life in this severe service; and (3) conducted an economic evaluation, based on the data, to quantify the impact of the technology. Chevron, one of the major producers of natural gas, has offered to host the test at a gas treating plant. KPS will use their position as a recognized leader in the construction of commercial amine plants for building the unit along with GORE providing the membranes. GTI will provide operator and data collection support during lab- and field-testing to assure proper analytical procedures are used. Kvaerner and GTI will perform the final economic evaluation. GTI will provide project management and be responsible for reporting and interactions with DOE on this project. Efforts this quarter have concentrated on field site selection. ChevronTexaco has nominated their Headlee Gas Plant in Odessa, TX for a commercial-scale dehydration test. Design and cost estimation for this new site are underway. Potting

  20. High temperature ceramic membrane reactors for coal liquid upgrading

    SciTech Connect

    Tsotsis, T.T.

    1992-01-01

    In this project we will study a novel process concept, i.e., the use of ceramic membrane reactors in upgrading of coal model compounds and coal derived liquids. In general terms, the USC research team is responsible for constructing and operating the membrane reactor apparatus and for testing various inorganic membranes for the upgrading of coal derived asphaltenes and coal model compounds. The USC effort will involve the principal investigator of this project and two graduate research assistants. The ALCOA team is responsible for the preparation of the inorganic membranes, for construction and testing of the ceramic membrane modules, and for measurement of their transport properties. The ALCOA research effort will involve Dr. Paul K. T. Liu, who is the project manager of the ALCOA research team, an engineer and a technician. UNOCAL's contribution will be limited to overall technical assistance in catalyst preparation and the operation of the laboratory upgrading membrane reactor and for analytical back-up and expertise in oil analysis and materials characterization. UNOCAL is a no-cost contractor but will be involved in all aspects of the project, as deemed appropriate.

  1. Designing lipids for selective partitioning into liquid ordered membrane domains.

    PubMed

    Momin, Noor; Lee, Stacey; Gadok, Avinash K; Busch, David J; Bachand, George D; Hayden, Carl C; Stachowiak, Jeanne C; Sasaki, Darryl Y

    2015-04-28

    Self-organization of lipid molecules into specific membrane phases is key to the development of hierarchical molecular assemblies that mimic cellular structures. While the packing interaction of the lipid tails should provide the major driving force to direct lipid partitioning to ordered or disordered membrane domains, numerous examples show that the headgroup and spacer play important but undefined roles. We report here the development of several new biotinylated lipids that examine the role of spacer chemistry and structure on membrane phase partitioning. The new lipids were prepared with varying lengths of low molecular weight polyethylene glycol (EGn) spacers to examine how spacer hydrophilicity and length influence their partitioning behavior following binding with FITC-labeled streptavidin in liquid ordered (Lo) and liquid disordered (Ld) phase coexisting membranes. Partitioning coefficients (Kp Lo/Ld) of the biotinylated lipids were determined using fluorescence measurements in studies with giant unilamellar vesicles (GUVs). Compared against DPPE-biotin, DPPE-cap-biotin, and DSPE-PEG2000-biotin lipids, the new dipalmityl-EGn-biotin lipids exhibited markedly enhanced partitioning into liquid ordered domains, achieving Kp of up to 7.3 with a decaethylene glycol spacer (DP-EG10-biotin). We further demonstrated biological relevance of the lipids with selective partitioning to lipid raft-like domains observed in giant plasma membrane vesicles (GPMVs) derived from mammalian cells. Our results found that the spacer group not only plays a pivotal role for designing lipids with phase selectivity but may also influence the structural order of the domain assemblies.

  2. Porous Membranes Built Up from Hydrophilic Poly(ionic liquid)s.

    PubMed

    Täuber, Karoline; Zimathies, Annett; Yuan, Jiayin

    2015-12-01

    Porous polymer membranes made via electrostatic complexation are fabricated from a water-soluble poly(ionic liquid) (PIL) for the first time. The porous structure is formed as a consequence of simultaneous phase separation of the PIL and ionic complexation with an acid, which occurred in a basic solution of a nonsolvent for the PIL. These membranes have a stimuli-responsive porosity, with open and closed pores in isopropanol and in water, respectively. This property is quantitatively demonstrated in filtration experiments, where water is passing much slower through the membranes than isopropanol.

  3. Ionic Conductivity of Nanostructured Block Copolymer and Ionic Liquid Membranes

    NASA Astrophysics Data System (ADS)

    Hoarfrost, Megan L.; Virgili, Justin M.; Segalman, Rachel A.

    2010-03-01

    Block copolymer and ionic liquid mixtures are of interest for creating ionically conductive, thermally stable, and nanostructured membranes. For mixtures of poly(styrene-b-2-vinylpyridine) (S2VP) and the ionic liquid bis(trifluoromethanesulfonyl)imide ([Im][TFSI]), nanostructured ion-conducting domains are formed due to [Im][TFSI] selectively residing in the P2VP domains of the block copolymer. The dependence of ionic conductivity on temperature, ionic liquid loading, and volume fraction of PS in the neat block copolymer was investigated for membranes with the matrix phase being P2VP/[Im][TFSI]. It was determined that the temperature dependence of conductivity follows the Vogel-Tamman-Fulcher equation, with the activation energy determined by the ratio of [Im][TFSI] to 2VP monomers. The overall weight fraction of [Im][TFSI] in the mixtures, however, is the dominating factor determining conductivity, regardless of PS volume fraction. The insight gained from this work will be important for further investigation into the effect on the ion transport properties of ionic liquids when confined to minority nanostructured domains.

  4. Two-dimensional materials for novel liquid separation membranes

    NASA Astrophysics Data System (ADS)

    Ying, Yulong; Yang, Yefeng; Ying, Wen; Peng, Xinsheng

    2016-08-01

    Demand for a perfect molecular-level separation membrane with ultrafast permeation and a robust mechanical property for any kind of species to be blocked in water purification and desalination is urgent. In recent years, due to their intrinsic characteristics, such as a unique mono-atom thick structure, outstanding mechanical strength and excellent flexibility, as well as facile and large-scale production, graphene and its large family of two-dimensional (2D) materials are regarded as ideal membrane materials for ultrafast molecular separation. A perfect separation membrane should be as thin as possible to maximize its flux, mechanically robust and without failure even if under high loading pressure, and have a narrow nanochannel size distribution to guarantee its selectivity. The latest breakthrough in 2D material-based membranes will be reviewed both in theories and experiments, including their current state-of-the-art fabrication, structure design, simulation and applications. Special attention will be focused on the designs and strategies employed to control microstructures to enhance permeation and selectivity for liquid separation. In addition, critical views on the separation mechanism within two-dimensional material-based membranes will be provided based on a discussion of the effects of intrinsic defects during growth, predefined nanopores and nanochannels during subsequent fabrication processes, the interlayer spacing of stacking 2D material flakes and the surface charge or functional groups. Furthermore, we will summarize the significant progress of these 2D material-based membranes for liquid separation in nanofiltration/ultrafiltration and pervaporation. Lastly, we will recall issues requiring attention, and discuss existing questionable conclusions in some articles and emerging challenges. This review will serve as a valuable platform to provide a compact source of relevant and timely information about the development of 2D material-based membranes as

  5. Ionic liquid-based materials: a platform to design engineered CO2 separation membranes.

    PubMed

    Tomé, Liliana C; Marrucho, Isabel M

    2016-05-21

    During the past decade, significant advances in ionic liquid-based materials for the development of CO2 separation membranes have been accomplished. This review presents a perspective on different strategies that use ionic liquid-based materials as a unique tuneable platform to design task-specific advanced materials for CO2 separation membranes. Based on compilation and analysis of the data hitherto reported, we provide a judicious assessment of the CO2 separation efficiency of different membranes, and highlight breakthroughs and key challenges in this field. In particular, configurations such as supported ionic liquid membranes, polymer/ionic liquid composite membranes, gelled ionic liquid membranes and poly(ionic liquid)-based membranes are detailed, discussed and evaluated in terms of their efficiency, which is attributed to their chemical and structural features. Finally, an integrated perspective on technology, economy and sustainability is provided.

  6. Hollow fiber gas-liquid membrane contactors for acid gas capture: a review.

    PubMed

    Mansourizadeh, A; Ismail, A F

    2009-11-15

    Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas-liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas-liquid membrane contactors for acid gas removal were also briefly discussed.

  7. Emulsion liquid membrane for textile dye removal: Stability study

    NASA Astrophysics Data System (ADS)

    Kusumastuti, Adhi; Syamwil, Rodia; Anis, Samsudin

    2017-03-01

    Although textile dyes is basically available in very low concentration; it should be removed due to the toxicity to human body and environment. Among the existing methods, emulsion liquid membrane (ELM) is a promising method by providing high interfacial area and the ability to remove a very low concentration of the solute. The optimal emulsions were produced using commercially supplied homogeniser. The drop size was measured by the aid of microscope and image J software. Initially, methylene blue in simulated wastewater was extracted using a stirrer. Methylene blue concentration was determined using spectrophotometer. The research obtained optimal emulsion at surfactant concentration of 4 wt. %, kerosene as diluent, emulsification time of 30 min, emulsification speed of 2000 rpm. The lowest membrane breakage and the longest stability time were about 0.11% and 150 min, respectively.

  8. Digital simulation of associated and nonassociated liquid membrane electrochemical properties.

    PubMed Central

    Stover, F S; Buck, R P

    1976-01-01

    The method and results of a digital simulation of electrochemical properties for associated and nonassociated liquid ion-exchange membranes are presented. It is assumed that the membranes is ideally permselective, sites are completely trapped, electroneutrality holds everywhere in the membrane, and the bathing solutions contain no more than two counterions, of which one is completely dissociated in the membrane. Electrochemical properties are simulated for the single counterion case and in the interference region. Concentration profiles, potentiometric responses, transient potential responses to activity steps, and current-voltage curves are given and the effects of ion-pairing and species mobilities are studied. It is found that ion-pairing increases the potentiometric selectivity toward the complexing ion over the noncomplexing ion. Transient responses to an ion activity step are shown to depend in a complex way on the ion-pair formation constant and the various mobilities. Current-voltage curves are simulated for varying degrees of ion-pairing and qualitative agreement is found with previous theoretical treatments, as well as quantitative agreement in those cases where closed-form expressions are known. PMID:938716

  9. Removal of phenols from wastewater using liquid membranes in a microporous hollow-fiber-membrane extractor

    SciTech Connect

    Nanoti, A.; Ganguly, S.K.; Goswami, A.N.; Rawat, B.S.

    1997-10-01

    Phenols occur as toxic contaminants in effluent waters from industries such as oil refining, coke and coal processing, phenolic resin manufacture, and several other chemical and metallurgical operations. This paper reports experimental data on the removal of phenol from aqueous solutions using emulsion liquid membranes in a microporous hollow-fiber extractor. The hollow-fiber extractor appears to offer significant advantages over conventional liquid-liquid contactors for this separation because emulsion leakage and swell are practically eliminated even when treating high phenolic feeds. The overall mass-transfer coefficients are seen to be more strongly dependent on the phase flow rates among the parameters studied. The experimental mass-transfer coefficients have been predicted by a resistance-in-series model.

  10. Behavior of solute adsorbed at the liquid-liquid interface during solvent extraction with porous-membrane phase separators

    SciTech Connect

    Persaud, G.; Xiu-min, T.; Cantwell, F.F.

    1987-01-01

    Porous membranes are used effectively as phase separators in analytical solvent extraction. When the solute involved can be adsorbed at the liquid-liquid interface, it is found that more vigorous agitation of the mixture causes a decrease in concentration of solute in the liquid flowing through the porous membrane. It is shown experimentally for the interfacially adsorbed component methylene blue perchlorate that the distribution isotherm between chloroform and water is the same in stirred and unstirred mixtures. This suggests that the interfacially adsorbed solute remains at the interface and does not enter the bulk liquid phases during the membrane-induced coalescence and phase separation. Hydrodynamic and diffusion rate calculations confirm this conclusion by showing that the residence time of the solute deposited at the liquid-liquid interface near the membrane (0.1 s) is too short for solute to diffuse through the stagnant Nernst diffusion layer.

  11. Liquid-liquid extraction of uranium(VI) in the system with a membrane contactor.

    PubMed

    Biełuszka, Paweł; Zakrzewska, Grażyna; Chajduk, Ewelina; Dudek, Jakub

    Raising role of the nuclear power industry, including governmental plans for the construction of first nuclear power plant in Poland, creates increasing demand for the uranium-based nuclear fuels. The project implemented by Institute of Nuclear Chemistry and Technology concerns the development of effective methods for uranium extraction from low-grade ores and phosphorites for production of yellow cake-U3O8. The Liqui-Cel(®) Extra-Flow 2.5 × 8 Membrane Contactor produced by CELGARD LLC (Charlotte, NC) company is the main component of the installation for liquid-liquid extraction applied for processing of post leaching liquors. In the process of membrane extraction the uranyl ions from aqueous phase are transported through the membrane into organic phase. The flow of two phases in the system was arranged in co-current mode. The very important element of the work was a selection of extracting agents appropriate for the membrane process. After preliminary experiments comprising tests of membrane resistivity and determination of extraction efficiency, di(2-ethylhexyl)phosphoric acid was found to be most favourable. An important aspect of the work was the adjustment of hydrodynamic conditions in the capillary module. To avoid the membrane wettability by organic solvent and mixing two phases equal pressure drops along the membrane module to minimize the transmembrane pressure, were assumed. Determination of pressure drop along the module was conducted using Bernoulli equation. The integrated process of extraction/re-extraction conducted in continuous mode with application of two contactors was designed.

  12. Direct liquid-feed fuel cell with membrane electrolyte and manufacturing thereof

    NASA Technical Reports Server (NTRS)

    Narayanan, Sekharipuram (Inventor); Surampudi, Subbarao (Inventor); Halpert, Gerald (Inventor)

    1999-01-01

    An improved direct liquid-feed fuel cell having a solid membrane electrolyte for electrochemical reactions of an organic fuel. Improvements in interfacing of the catalyst layer and the membrane and activating catalyst materials are disclosed.

  13. Dynamic single-interface hollow fiber liquid phase microextraction of Cr(VI) using ionic liquid containing supported liquid membrane.

    PubMed

    Pimparu, Rungaroon; Nitiyanontakit, Sira; Miró, Manuel; Varanusupakul, Pakorn

    2016-12-01

    The concept of dynamic single-interface hollow fiber membrane liquid-phase microextraction (HF-LPME), where the target analyte was extracted on-line and eluted inside the lumen of the HF membrane, was explored. An ionic liquid containing supported liquid membrane was used for the trace determination of Cr(VI) as a model compound. Since the extraction took place on-line inside the hollow fiber membrane, the mass transfer behavior was described and discussed in comparison with the conventional HF-LPME. The extraction efficiency was improved by a recirculation configuration of the sample solution at relatively high sampling flow rates as a result of the increased effective contact area. The positive pressure observed to be built up during extraction was overcome by a flow-balancing pressure design. The dynamic single-interface HF-LPME method with an enrichment factor of 41, a detection limit of 1.2µgL(-1) and determination limit of 4.0µgL(-1) was successfully applied to the reliable determination of Cr(VI) from environmental water samples. The quantification limit is below the maximum contaminant level in drinking water, set at 10µgL(-1) of hexavalent chromium by the California Environmental Protection Agency.

  14. Mercury removal from aqueous streams utilizing microemulsion liquid membranes

    SciTech Connect

    Larson, K.A.; Wiencek, J.M.

    1994-11-01

    The goal of this work is the removal of mercury ion from wastewater using thermodynamically stable microemulsions as liquid membranes. The research focuses on identification and modeling of the appropriate aqueous and organic phase equilibrium reactions for mercury extraction and stripping, comparison of extraction kinetics between coarse emulsions and microemulsions, and demulsification and recovery of the emulsion components. An oleic acid microemulsion liquid membrane (water-in-oil) containing sulfuric acid as the internal phase reduces the feed phase mercury concentration from 460 mg/l to 0.84 mg/l in a single contacting. This compares favorably with a control extraction (oleic acid/no internal phase) which results in a final concentration of 20 mg/l Hg{sup +2}. Microemulsions can be demulsified using butanol as an additive. The demulsification kinetics are proportional to butanol concentration and temperature and inversely proportional to surfactant concentration. The demulsification rate is second order with respect to water concentration which implies that the rate-limiting step in the process is the rate of internal phase droplet encounters. Proof-of-principle experiments demonstrate the ability to extract mercury ion using microemulsions formulated with recycled organic phase, albeit at a somewhat reduced efficiency. The reduced efficiency is attributed to increased internal phase leakage due to residual butanol in the oil phase. Finally, the cycle is brought around full circle by recovering metallic mercury from the internal phase by electroplating. 27 refs., 11 figs., 1 tab.

  15. Emulsion-liquid-membrane extraction of copper using a hollow-fiber contactor

    SciTech Connect

    Hu, S.Y.B.; Wiencek, J.M.

    1998-03-01

    A novel extraction technique using an emulsion liquid membrane within a hollow-fiber contactor was developed and utilized to extract copper using LIX 84 extractant. Emulsion liquid membranes are capable of extracting metals from dilute waste streams to levels much below those possible by equilibrium-limited solvent extraction. Utilizing an emulsion liquid membrane within a hollow-fiber contactor retains the advantages of emulsion-liquid-membrane extraction, namely, simultaneous extraction and stripping, while eliminating problems encountered in dispersive contacting methods, such as swelling and leakage of the liquid membrane. Mathematical models for extraction in hollow-fiber contactors were developed. The models satisfactorily predict the outcome of both simple solvent extraction and emulsion-liquid-membrane extraction of copper by LIX 84 in a hollow-fiber contactor over a wide range of conditions. Emulsion-liquid-membrane extraction performs exceptionally well when the extraction is close to equilibrium limit. It is also capable of extracting a solute f/rom very dilute solutions. Stability of the liquid membrane is not crucial when used in hollow-fiber contactors; the surfactant in liquid membrane can be reduced or even eliminated without severely impairing the performance.

  16. The use of emulsions, microemulsions, and hollow fiber contactors as liquid membranes

    SciTech Connect

    Wiencek, J.M.; Hu, S.Y.; Raghuraman, B.

    1995-12-01

    Liquid membranes as a generic concept have primarily involved the use of either porous solid film impregnated with a liquid carrier or emulsified systems employed in a stirred contactor. Although such systems can display high selectivities and reasonable flux, the stability of the liquid membrane to rupture (i.e. leakage) and unwanted water transport (i.e. swell) have limited their commercial application. Our lab has focused on developing improved emulsion liquid membranes. In particular, we have investigated the possibility of employing microemulsions as liquid membranes to separate metals (especially mercury) from contaminated water. Our most current work on the use of hollow fiber contactors as a means of minimizing swell and leakage in emulsion liquid membrane systems will also be presented.

  17. Ionic Liquids and New Proton Exchange Membranes for Fuel Cells

    NASA Technical Reports Server (NTRS)

    Belieres, Jean-Philippe

    2004-01-01

    There is currently a great surge of activity in fuel cell research as laboratories across the world seek to take advantage of the high energy capacity provided by &el cells relative to those of other portable electrochemical power systems. Much of this activity is aimed at high temperature fie1 cells, and a vital component of such &el cells must be the availability of a high temperature stable proton-permeable membrane. NASA Glenn Research Center is greatly involved in developing this technology. Other approaches to the high temperature fuel cell involve the use of single- component or almost-single-component electrolytes that provide a path for protons through the cell. A heavily researched case is the phosphoric acid fuel cell, in which the electrolyte is almost pure phosphoric acid and the cathode reaction produces water directly. The phosphoric acid fie1 cell delivers an open circuit voltage of 0.9 V falling to about 0.7 V under operating conditions at 170 C. The proton transport mechanism is mainly vehicular in character according to the viscosity/conductance relation. Here we describe some Proton Transfer Ionic Liquids (PTILs) with low vapor pressure and high temperature stability that have conductivities of unprecedented magnitude for non-aqueous systems. The first requirement of an ionic liquid is that, contrary to experience with most liquids consisting of ions, it must have a melting point that is not much above room temperature. The limit commonly suggested is 100 C. PTILs constitute an interesting class of non-corrosive proton-exchange electrolyte, which can serve well in high temperature (T = 100 - 250 C) fuel cell applications. We will present cell performance data showing that the open circuit voltage output, and the performance of a simple H2(g)Pt/PTIL/Pt/O2(g) fuel cell may be superior to those of the equivalent phosphoric acid electrolyte fuel cell both at ambient temperature and temperatures up to and above 200 C. My work at NASA Glenn Research

  18. Calixarene-Mediated Liquid-Membrane Transport of Choline Conjugates.

    PubMed

    Adhikari, Birendra Babu; Fujii, Ayu; Schramm, Michael P

    2014-05-01

    A series of supramolecular calixarenes efficiently transport distinct molecular species through a liquid membrane when attached to a receptor-complementary choline handle. Calix-[6]arene hexacarboxylic acid was highly effective at transporting different target molecules against a pH gradient. Both carboxylic- and phosphonic-acid-functionalized calix[4]arenes effect transport without requiring a pH or ion gradient. NMR binding studies, two-phase solvent extraction, and three-phase transport experiments reveal the necessary and subtle parameters to effect the transport of molecules attached to a choline "handle". On the other hand, rescorin[4]arene cavitands, which have similar guest recognition profiles, did not transport guest molecules. These developments reveal new approaches towards attempting synthetic-receptor-mediated selective small-molecule transport in vesicular and cellular systems.

  19. A SAXS study on nanostructure evolution in water free membranes containing ionic liquid: from dry membrane to saturation.

    PubMed

    Sekhon, Satpal Singh; Park, Jin-Soo; Choi, Young-Woo

    2010-11-07

    Small-angle X-ray scattering (SAXS) technique has been used to study the evolution of ionomer peak in the recast Nafion membranes containing the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF(4)). To the best of our knowledge, this is the first report dealing with the study of membranes containing different concentrations of the ionic liquid (EMIBF(4)), from the dry (no ionic liquid) to the saturation (containing 70 wt% ionic liquid) state to understand the evolution of the ionomer peak and the formation of ionic aggregates in these anhydrous membranes. The small-angle scattering maximum (ionomer peak) has been observed to shift continuously toward lower scattering vector (q) values as the ionic liquid content increases. The ionic conductivity behavior for the membranes containing ionic liquid has been found to be closely related with the change of slope of the double logarithmic plot between the reciprocal of the position of the ionomer peak and the polymer weight fraction. The q region over which Porod's law has been obeyed in different membranes was initially narrow and has been observed to widen with an increase in the content of the ionic liquid.

  20. Gramicidin Alters the Lipid Compositions of Liquid-Ordered and Liquid-Disordered Membrane Domains

    NASA Astrophysics Data System (ADS)

    Hassan-Zadeh, Ebrahim; Huang, Juyang

    2012-10-01

    The effects of adding 1 mol % of gramicidin A to the well-known DOPC/DSPC/cholesterol lipid mixtures were investigated. 4-component giant unilamellar vesicles (GUV) were prepared using our recently developed Wet-Film method. The phase boundary of liquid-ordered and liquid-disordered (Lo-Ld) coexisting region was determined using video fluorescence microscopy. We found that if cares were not taken, light-induced domain artifacts could significantly distort the measured phase boundary. After testing several fluorescence dyes, we found that the emission spectrum of Nile Red is quite sensitive to membrane composition. By fitting the Nile Red emission spectra at the phase boundary to the spectra in the Lo-Ld coexisting region, the thermodynamic tie-lines were determined. As an active component of lipid membranes, gramicidin not only partitions favorably into the liquid-disordered (Ld) phase, it also alters the phase boundary and thermodynamic tie-lines. Even at as low as 1 mol %, gramicidin decreases the cholesterol mole fraction of Ld phase and increases the area of Lo phase.

  1. Removal of phenols from aqueous solutions by emulsion liquid membranes.

    PubMed

    Reis, M Teresa A; Freitas, Ondina M F; Agarwal, Shiva; Ferreira, Licínio M; Ismael, M Rosinda C; Machado, Remígio; Carvalho, Jorge M R

    2011-09-15

    The present study deals with the extraction of phenols from aqueous solutions by using the emulsion liquid membranes technique. Besides phenol, two derivatives of phenol, i.e., tyrosol (2-(4-hydroxyphenyl)ethanol) and p-coumaric acid (4-hydroxycinnamic acid), which are typical components of the effluents produced in olive oil plants, were selected as the target solutes. The effect of the composition of the organic phase on the removal of solutes was examined. The influence of pH of feed phase on the extraction of tyrosol and p-coumaric was tested for the membrane with Cyanex 923 as an extractant. The use of 2% Cyanex 923 allowed obtaining a very high extraction of phenols (97-99%) in 5-6 min of contact time for either single solute solutions or for their mixtures. The removal efficiency of phenol and p-coumaric acid attained equivalent values by using the system with 2% isodecanol, but the removal rate of tyrosol was found greatly reduced. The extraction of tyrosol and p-coumaric acid from their binary mixture was also analysed for different operating conditions like the volume ratio of feed phase to stripping phase (sodium hydroxide), the temperature and the initial concentration of solute in the feed phase.

  2. Thinning of reverse osmosis membranes by ionic liquids

    NASA Astrophysics Data System (ADS)

    Meng, Hong; Gong, Beibei; Geng, Tao; Li, Chunxi

    2014-02-01

    In this study, ionic liquids (ILs) were used to thin out the dense layer and, in turn, tune the surface properties and separation performance of commercial aromatic polyamide reverse osmosis membranes. It was observed that the structure of the ILs and dipping time had a strong impact on the dense layer thickness and morphology. This can be understood in terms of the dissolubility and interaction force between ILs and the organic membrane surface, such as hydrogen bonding and π-π interactions. Among the ILs synthesized, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) showed the most promising thinning effects. It was observed that the thickness of the dense layer on the surface decreased from 127 to 67 nm after dipping treatment with [BMIM]Cl for 24 h. The water flux was enhanced by 20% at the expense of a slight decline of salt rejection. AFM, contact angle and zeta potential analyses suggest that the surface hydrophilicity and electronegativity increased, while the roughness decreased, which improved the anti-fouling properties.

  3. Bilayer membrane permeability of ionic liquid-filled block copolymer vesicles in aqueous solution.

    PubMed

    Bai, Zhifeng; Zhao, Bin; Lodge, Timothy P

    2012-07-19

    The bilayer membrane permeability of block copolymer vesicles ("polymersomes") with ionic liquid interiors dispersed in water is quantified using fluorescence quenching. Poly((1,2-butadiene)-b-ethylene oxide) (PB-PEO) block copolymer vesicles in water with their interiors filled with a common hydrophobic ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, were prepared containing a hydrophobic dye, Nile Red, by intact migration of dye-encapsulated vesicles from the ionic liquid to water at room temperature. A small quencher molecule, dichloroacetamide, was added to the aqueous solution of the dye-loaded vesicles, and the permeation of the quencher passing through the membrane into the interior was determined from the fluorescence quenching kinetics. Rapid permeation of the quencher across the nanoscale membrane was observed, consistent with the high fluidity of the liquid polybutadiene membrane. Two different PB-PEO copolymers were employed, in order to vary the thickness of the solvophobic membrane. A significant increase in membrane permeability was also observed with decreasing membrane thickness, which is tentatively attributable to differences in quencher solubility in the membranes. Quantitative migration of the vesicles from the aqueous phase back to an ionic liquid phase was achieved upon heating. These microscopically heterogeneous and thermoresponsive vesicles with permeable and robust membranes have potential as recyclable nanoreactors, in which the high viscosity and capital expense of an ionic liquid reaction medium can be mitigated, while retaining the desirable features of ionic liquids as reaction media, and facile catalyst recovery.

  4. Advanced Supported Liquid Membranes for Carbon Dioxide Control in Extravehicular Activity Applications

    NASA Technical Reports Server (NTRS)

    Wickham, David T. (Inventor); Gleason, Kevin J. (Inventor); Cowley, Scott W. (Inventor)

    2015-01-01

    There is disclosed a portable life support system with a component for removal of at least one selected gas. In an embodiment, the system includes a supported liquid membrane having a first side and a second side in opposition to one another, the first side configured for disposition toward an astronaut and the second side configured for disposition toward a vacuum atmosphere. The system further includes an ionic liquid disposed between the first side and the second side of the supported liquid membrane, the ionic liquid configured for removal of at least one selected gas from a region housing the astronaut adjacent the first side of the supported liquid membrane to the vacuum atmosphere adjacent the second side of the supported liquid membrane. Other embodiments are also disclosed.

  5. Removal and recovery of heavy metals from wastewaters by supported liquid membranes.

    PubMed

    Yang, X J; Fane, A G; MacNaughton, S

    2001-01-01

    The removal and recovery of Cu, Cr and Zn from plating rinse wastewater using supported liquid membranes (SLM) are investigated. SLMs with specific organic extractants as the liquid membrane carriers in series are able to remove and concentrate heavy metals with very high purity, which is very promising for recycling of heavy metals in the electroplating industry. A technical comparison between the membrane process and the conventional chemical precipitation process was made.

  6. Innovative methods to stabilize liquid membranes for removal of radionuclides from groundwater

    SciTech Connect

    Lokhandwala, K.

    1997-10-01

    In this Phase I Small Business Innovation Research program, Membrane Technology Research, Inc., is developing a stable liquid membrane for extracting uranium and other radionuclides from groundwater. The improved membrane can also be applied to separation of other metal ions from aqueous streams in industrial operations.

  7. Design criteria for extraction with chemical reaction and liquid membrane permeation

    NASA Technical Reports Server (NTRS)

    Bart, H. J.; Bauer, A.; Lorbach, D.; Marr, R.

    1988-01-01

    The design criteria for heterogeneous chemical reactions in liquid/liquid systems formally correspond to those of classical physical extraction. More complex models are presented which describe the material exchange at the individual droplets in an extraction with chemical reaction and in liquid membrane permeation.

  8. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 1, September 21, 1989--December 20, 1989

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    In this project we well evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated. (VC)

  9. Uphill transport of rare-earth metals through a highly stable supported liquid membrane based on an ionic liquid.

    PubMed

    Kubota, Fukiko; Shimobori, Yousuke; Koyanagi, Yusuke; Shimojo, Kojiro; Kamiya, Noriho; Goto, Masahiro

    2010-01-01

    We have developed a highly stable supported liquid membrane based on ionic liquids (ILs) for the separation of rare-earth metals, employing N,N-dioctyldiglycol amic acid as a mobile carrier. The quantitative transport of Y and Eu through the membrane was successfully attained, and separation from metal impurities, Zn, was efficiently accomplished. A membrane stable enough for long-term operation was constructible from imidazolium-based ILs having a longer alkyl chain, such as octyl or dodecyl groups in an imidazolium cation.

  10. Cellulose triacetate doped with ionic liquids for membrane gas separation

    NASA Astrophysics Data System (ADS)

    Lam, Benjamin Fatt Soon

    The doping of cellulose triacetate (CTA) with imidazolium based ionic liquids (ILs) is investigated in order to reduce the polymer crystallinity and enhance the affinity with CO2, thus increasing CO2 permeability and CO2/light gas selectivity. CTA membranes doped with [emim] BF4 or [emim] DCA were prepared, and the effect of the ILs loading on properties, such as crystallinity, density, degradation temperature, glass transition temperature, and gas transport properties, has been determined. In general, doping with IL reduces the crystallinity in CTA, increasing gas solubility, diffusivity and permeability. The ILs doping also increases CO 2/CH4 solubility selectivity and CO2/N2 permeability selectivity, due to the affinity of these ILs with CO2, instead of light gases such as CH4 and N2. This study provides a mechanistic understanding of interaction of ILs and CTA, and demonstrates an effective route in manipulating the morphology and gas transport properties of semi crystalline polymers by doping with ILs.

  11. Interfacial interactions in aprotic ionic liquid based protonic membrane and its correlation with high temperature conductivity and thermal properties.

    PubMed

    Mistry, Mayur K; Subianto, Surya; Choudhury, Namita Roy; Dutta, Naba K

    2009-08-18

    Novel supported liquid membranes (SLMs) have been developed by impregnating Nafion and Hyflon membranes with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI). These supported liquid membranes were characterized in terms of their ionic liquid uptake behavior, leaching of ionic liquid by water, thermal stability, mechanical properties, glass transition temperature, ion exchange capacity, and proton conductivity. In general, modified membranes are more flexible than unmodified samples due to the plasticization effects of the ionic liquid. However, these supported liquid membranes exhibit a significant increase in their operational stability and proton conductivity over unmodified membranes. We also demonstrate that proton conductivity of these supported liquid membranes allows conduction of protons in anhydrous conditions with conductivity increasing with temperature. Conductivity of up to 3.58 mS cm(-1) has been achieved at 160 degrees C in dry conditions, making these materials promising for various electrochemical applications.

  12. Separations of hazardous organics from gas and liquid feedstreams using phosphazene polymer membranes

    SciTech Connect

    Peterson, E.S.; Stone, M.L.; Cummings, D.G.; McCaffrey, R.R.

    1993-01-01

    The liquid-liquid and gas separation properties for the separation of hazardous organic feed streams using pervaporation and gas separation methods with poly[bis(phenoxy)phosphazene] based membranes are reported. Liquid transport behavior was determined using pervaporation techniques. The preliminary gas separations were studied using a mixed gas separation method which the authors have described previously. Using the membrane pervaporation technique, separation factors of 10,000 have been routinely achieved for the separation of methylene chloride from water. Other tests have shown similar results for the removal of hydrocarbon vapors from air. Membranes were prepared using solution casting techniques. Solvent evaporation rates during the casting and subsequent curing processes were controlled to provide a consistent membrane microstructure. These results suggest that polyphosphazene membrane technology could effectively be used in cleaning up air and ground water that has been contaminated with chlorinated hydrocarbons.

  13. Super liquid-repellent gas membranes for carbon dioxide capture and heart-lung machines.

    PubMed

    Paven, Maxime; Papadopoulos, Periklis; Schöttler, Susanne; Deng, Xu; Mailänder, Volker; Vollmer, Doris; Butt, Hans-Jürgen

    2013-01-01

    In a gas membrane, gas is transferred between a liquid and a gas through a microporous membrane. The main challenge is to achieve a high gas transfer while preventing wetting and clogging. With respect to the oxygenation of blood, haemocompatibility is also required. Here we coat macroporous meshes with a superamphiphobic-or liquid repellent-layer to meet this challenge. The superamphiphobic layer consists of a fractal-like network of fluorinated silicon oxide nanospheres; gas trapped between the nanospheres keeps the liquid from contacting the wall of the membrane. We demonstrate the capabilities of the membrane by capturing carbon dioxide gas into a basic aqueous solution and in addition use it to oxygenate blood. Usually, blood tends to clog membranes because of the abundance of blood cells, platelets, proteins and lipids. We show that human blood stored in a superamphiphobic well for 24 h can be poured off without leaving cells or adsorbed protein behind.

  14. Supported ionic liquid membranes for removal of dioxins from high-temperature vapor streams.

    PubMed

    Kulkarni, Prashant S; Neves, Luisa A; Coelhoso, Isabel M; Afonso, Carlos A M; Crespo, João G

    2012-01-03

    Dioxins and dioxin-like chemicals are predominantly produced by thermal processes such as incineration and combustion at concentrations in the range of 10-100 ng of I-TEQ/kg (I-TEQ = international toxic equivalents). In this work, a new approach for the removal of dioxins from high-temperature vapor streams using facilitated supported ionic liquid membranes (SILMs) is proposed. The use of ceramic membranes containing specific ionic liquids, with extremely low volatility, for dioxin removal from incineration sources is proposed owing to their stability at very high temperatures. Supported liquid membranes were prepared by successfully immobilizing the ionic liquids tri-C(8)-C(10)-alkylmethylammonium dicyanamide ([Aliquat][DCA]) and 1-n-octyl-3-methylimidazolium dicyanamide ([Omim][DCA]) inside the porous structure of ceramic membranes. The porous inorganic membranes tested were made of titanium oxide (TiO(2)), with a nominal pore size of 30 nm, and aluminum oxide (Al(2)O(3)), with a nominal pore size of 100 nm. The ionic liquids were characterized, and the membrane performance was assessed for the removal of dioxins. Different materials (membrane pore size, type of ionic liquid, and dioxin) and different operating conditions (temperature and flow rate) were tested to evaluate the efficiency of SILMs for dioxin removal. All membranes prepared were stable at temperatures up to 200 °C. Experiments with model incineration gas were also carried out, and the results obtained validate the potential of using ceramic membranes with immobilized ionic liquids for the removal of dioxins from high-temperature vapor sources.

  15. Emulsion Liquid Membrane Removal of Arsenic and Strontium from Wastewater: AN Experimental and Theoretical Study.

    NASA Astrophysics Data System (ADS)

    Zhou, Ding-Wei

    The emulsion liquid membrane (ELM) technique has been successfully applied on the removal of arsenic (As) from metallurgical wastewater and the removal of strontium (Sr) from radioactive wastewater. This study consisted of experimental work and mathematical modeling. Extraction of arsenic by an emulsion liquid membrane was firstly investigated. The liquid membrane used was composed of 2-ethylhexyl alcohol (2EHA) as the extractant, ECA4360J as the surfactant, and Exxsol D-80 solvent (or heptane) as the diluent. The sulfuric acid and sodium hydroxide solutions were used as the external and internal phases, respectively. The arsenic removal efficiency reached 92% within 15 minutes in one stage. Extraction and stripping chemistries were postulated and investigated. It was observed that extraction efficiency and rate increase with the increase of acidic strength and alkali strength in the external and internal phases, respectively. It was also observed that the removal selectivity of arsenic over copper is extremely high. Strontium-90 is one of the major radioactive metals appearing in nuclear wastewater. The emulsion liquid membrane process was investigated as a separation method by using the non-radioactive ^{87}Sr as its substitute. In our study, the membrane phase was composed of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant, ECA4360J as the surfactant and Exxsol D-80 as the diluent. A sulfuric acid solution was used in the internal phase as the stripping agent. The pH range in the external phase was determined by the extraction isotherm. Under the most favorable operating condition, the strontium removal efficiency can reach 98% in two minutes. Mass transfer of the emulsion liquid membrane (ELM) system was modeled mathematically. Our model took into account the following: mass transfer of solute across the film between the external phase and the membrane phase, chemical equilibrium of the extraction reaction at the external phase-membrane interface

  16. Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

    SciTech Connect

    Rogers, J.D.

    1994-08-04

    This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

  17. Cholinium-based supported ionic liquid membranes: a sustainable route for carbon dioxide separation.

    PubMed

    Tomé, Liliana C; Patinha, David J S; Ferreira, Rui; Garcia, Helga; Silva Pereira, Cristina; Freire, Carmen S R; Rebelo, Luís Paulo N; Marrucho, Isabel M

    2014-01-01

    Aiming at full sustainability of CO2 separation processes, a series of supported ionic liquid membranes based on environmentally friendly cholinium carboxylate ionic liquids were successfully prepared. Their gas permeation properties were measured and high permselectivities were obtained for both CO2 /CH4 and CO2 /N2 .

  18. Stress-sensor device based on flexoelectric liquid crystalline membranes.

    PubMed

    Rey, Alejandro D; Servio, Phillip; Herrera Valencia, Edtson Emilio

    2014-05-19

    Membrane flexoelectricity is an electromechanical coupling process that describes membrane bending and membrane electrical polarization caused by bending under electric fields. In this paper we propose, formulate, and characterize a stress-sensor device for mechanically loaded solids, consisting of a soft flexoelectric thin membrane attached to the loaded deformed solid. Because the curvature of the deformed solid is transferred to the attached flexoelectric membrane, the electromechanical transduction of the latter produces a charge that is proportional to the stress of the solid. The model of the stress-sensor device is based on the integration of the thermodynamics of polarizable membranes with isotropic solid elasticity, leading to a transfer function that identifies the elastic, electromechanical, and geometrical parameters involved in electrical-signal generation. The model is applied to representative normal bending and then to more complex off-axis bending of elastic bars. In all cases, a common transfer function shows the generic material and its geometric contributions. The sensor sensitivity increases linearly with flexoelectricity and the membrane-solid interface, and the sensitivity decreases with increasing membrane thickness and Young's modulus of the solid. The theoretical results contribute to ongoing experimental efforts towards the development of anisotropic soft-matter-based stress-sensor devices through solid-membrane interactions and electromechanical transduction.

  19. Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

    NASA Astrophysics Data System (ADS)

    Garaev, Valeriy; Kleperis, Janis; Pavlovica, Sanita; Vaivars, Guntars

    2012-08-01

    In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

  20. Reverse osmosis molecular differentiation of organic liquids using carbon molecular sieve membranes

    NASA Astrophysics Data System (ADS)

    Koh, Dong-Yeun; McCool, Benjamin A.; Deckman, Harry W.; Lively, Ryan P.

    2016-08-01

    Liquid-phase separations of similarly sized organic molecules using membranes is a major challenge for energy-intensive industrial separation processes. We created free-standing carbon molecular sieve membranes that translate the advantages of reverse osmosis for aqueous separations to the separation of organic liquids. Polymer precursors were cross-linked with a one-pot technique that protected the porous morphology of the membranes from thermally induced structural rearrangement during carbonization. Permeation studies using benzene derivatives whose kinetic diameters differ by less than an angstrom show kinetically selective organic liquid reverse osmosis. Ratios of single-component fluxes for para- and ortho-xylene exceeding 25 were observed and para- and ortho- liquid mixtures were efficiently separated, with an equimolar feed enriched to 81 mole % para-xylene, without phase change and at ambient temperature.

  1. Reverse osmosis molecular differentiation of organic liquids using carbon molecular sieve membranes.

    PubMed

    Koh, Dong-Yeun; McCool, Benjamin A; Deckman, Harry W; Lively, Ryan P

    2016-08-19

    Liquid-phase separations of similarly sized organic molecules using membranes is a major challenge for energy-intensive industrial separation processes. We created free-standing carbon molecular sieve membranes that translate the advantages of reverse osmosis for aqueous separations to the separation of organic liquids. Polymer precursors were cross-linked with a one-pot technique that protected the porous morphology of the membranes from thermally induced structural rearrangement during carbonization. Permeation studies using benzene derivatives whose kinetic diameters differ by less than an angstrom show kinetically selective organic liquid reverse osmosis. Ratios of single-component fluxes for para- and ortho-xylene exceeding 25 were observed and para- and ortho- liquid mixtures were efficiently separated, with an equimolar feed enriched to 81 mole % para-xylene, without phase change and at ambient temperature.

  2. REFORMING OF LIQUID HYDROCARBONS IN A NOVEL HYDROGEN-SELECTIVE MEMBRANE-BASED FUEL PROCESSOR

    SciTech Connect

    Shamsuddin Ilias

    2003-06-30

    We propose to develop an inorganic metal-metal composite membrane to study reforming of liquid hydrocarbons and methanol by equilibrium shift in membrane-reactor configuration, viewed as fuel processor. Based on our current understanding and experience in the Pd-ceramic composite membrane, we propose to further develop this membrane to a Pd and Pd-Ag alloy membrane on microporous stainless steel support to provide structural reliability from distortion due to thermal cycling. Because of the metal-metal composite structure, we believe that the associated end-seal problem in the Pd-ceramic composite membrane in tubular configuration would not be an issue at all. We plan to test this membrane as membrane-reactor-separator for reforming liquid hydrocarbons and methanol for simultaneous production and separation of high-purity hydrogen for PEM fuel cell applications. To improve the robustness of the membrane film and deep penetration into the pores, we have used osmotic pressure field in the electroless plating process. Using this novel method, we deposited thin Pd-film on the inside of microporous stainless steel tube and the deposited film appears to robust and defect free. Work is in progress to evaluate the hydrogen perm-selectivity of the Pd-stainless steel membrane.

  3. Membrane separations for solid-liquid clarification within lignocellulosic biorefining processes.

    PubMed

    Leberknight, Jennifer; Menkhaus, Todd J

    2013-01-01

    Membrane separations can be integrated into a biorefinery to reduce water and energy consumption. Unfortunately, current membrane materials suffer from severe fouling, which limits their applicability. Here, using analytical characterizations along with fouling models, we correlate membrane properties with performance metrics to provide a framework for optimal membrane selection during solid-liquid clarification of a biomass hydrolysate. Five membranes were evaluated: polyether sulfone, mixed cellulose esters, and three surface modified membranes with weak acid, strong acid, and weak base functionalities. Lignin was the primary component responsible for flux decline, due to physical entrapment and chemical adsorption. The best membrane performance (high and sustained flux, low fouling, and high separation factor) was correlated with higher surface roughness, lower hydrophobicity, neutral or positively charged zeta potential, and a larger number of smaller surface pores. These analyses provide valuable information for designing new materials for biorefining processes to reduce fouling and increase stability.

  4. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

    PubMed Central

    Couto, Ricardo; Neves, Luísa; Simões, Pedro; Coelhoso, Isabel

    2015-01-01

    In this work, a supported ionic liquid membrane (SILM) was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2) and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73) for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids. PMID:25594165

  5. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation.

    PubMed

    Couto, Ricardo; Neves, Luísa; Simões, Pedro; Coelhoso, Isabel

    2015-01-14

    In this work, a supported ionic liquid membrane (SILM) was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2) and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73) for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

  6. Liquid permeation and chemical stability of anodic alumina membranes

    PubMed Central

    Buldakov, Dmitrii A; Tishkin, Alexey A; Lukashin, Alexey V; Eliseev, Andrei A

    2017-01-01

    A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2 of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to 27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+ polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]−, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested. PMID:28382245

  7. Permeability of Rubbery and Glassy Membranes of Ionic Liquid Filled Polymersome Nanoreactors in Water.

    PubMed

    So, Soonyong; Yao, Letitia J; Lodge, Timothy P

    2015-12-03

    Nanoemulsion-like polymer vesicles (polymersomes) having ionic liquid interiors dispersed in water are attractive for nanoreactor applications. In a previous study, we demonstrated that small molecules could pass through rubbery polybutadiene membranes on a time scale of seconds, which is practical for chemical transformations. It is of interest to determine how sensitive the rate of transport is to temperature, particularly for membranes in the vicinity of the glass transition (Tg). In this work, the molecular exchange rate of 1-butylimidazole through glassy polystyrene (PS) bilayer membranes is investigated via pulsed field gradient nuclear magnetic resonance (PFG-NMR) over the temperature range from 25 to 70 °C. The vesicles were prepared by the cosolvent method in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI]), and four different polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock polymers with varying PS molecular weights were examined. The vesicles were transferred from the ionic liquid to water at room temperature to form nanoemulsion solutions of polymer vesicles in water. The exchange rate of 1-butylimidazole added to the aqueous solutions was observed under equilibrium conditions at each temperature. The exchange rate decreased as the membrane thickness increased, and the exchange rate through the glassy membranes was three to four times slower than through the rubbery polybutadiene membranes under the same experimental conditions. These results demonstrate that the permeability through nanosized membranes depends on both the dimension and chemistry of membrane-forming blocks. Furthermore, the exchange rate was investigated as a function of temperature in the vicinity of the Tg of PS-PEO membranes. The exchange rate, however, is not a strong function of the temperature in the vicinity of the membrane Tg, due to a combination of the nanoscopic dimension of the membrane, and some degree of solvent

  8. Proton Conducting Polymer Membrane Using The Ionic Liquid 2-Hydroxyethylammonium Lactate For Ethanol Fuel Cells

    NASA Astrophysics Data System (ADS)

    Oliveira, L.; José, N. M.; Boaventura, J.; Iglesias, M.; Mattedi, S.

    2011-12-01

    In this work, there were developed a proton conducting polymer membrane using an ammonium based protic ionic liquid: 2-hydroxyethylamominum lactate for use in proton exchange fuel cells (PEMFC). This kind of ionic liquid has been proven to be biodegradable and they have potentially low toxicity besides low cost of preparation, simple synthesis and purification. The prepared membranes are hybrid organic-inorganic materials. The polymeric matrix is prepared with polydimethylsiloxane (PDMS) mixed with tetraethoxysilane (TEOS) in a ratio of 70/30% in weight. Then, the eletrolytical mixture containing sodium monododecylsulfate (SDS) and the ionic liquid was introduced in the lattice near the gel point, there were used different proportions of the eletrolyte from 5 to 30% in weight. The prepared membranes were characterized using infrared spectroscopy (FTIR), X-ray diffraction (DRX), termogravimetric analysis (TGA), scanning electronic microscopy (SEM) and conductivity and impedance measurements. The prepared materials are flexible, with good thermal and mechanical stability and with a great potential to be used as conducting membranes of fuel cells. The used mixture minimizes the lixiviation lost of the ionic liquid from the polymeric membrane and enhances the cell efficiency if compared with traditional synthetic membranes.

  9. One-step extraction of polar drugs from plasma by parallel artificial liquid membrane extraction.

    PubMed

    Pilařová, Veronika; Sultani, Mumtaz; Ask, Kristine Skoglund; Nováková, Lucie; Pedersen-Bjergaard, Stig; Gjelstad, Astrid

    2017-02-01

    The new microextraction technique named parallel artificial liquid membrane extraction (PALME) was introduced as an alternative approach to liquid-liquid extraction of charged analytes from aqueous samples. The concept is based on extraction of analytes across a supported liquid membrane sustained in the pores of a thin polymeric membrane, a well-known extraction principle also used in hollow fiber liquid-phase microextraction (HF-LPME). However, the new PALME technique offers a more user-friendly setup in which the supported liquid membrane is incorporated in a 96 well plate system. Thus, high-throughput is achievable, in addition to the green chemistry offered by using PALME. The consumption of organic solvent is minimized to 3-5μL per sample. With a sample volume of 250μL and acceptor solution volume of 50μL, a maximal enrichment factor of five is achievable. Based on these parameters, a new method for extraction of polar basic drugs was developed in the present work. The basic drugs hydralazine, ephedrine, metaraminol, salbutamol, and cimetidine were used as model analytes, and were extracted from alkalized human plasma into an aqueous solution via the supported liquid membrane. The extraction was promoted by a carrier dissolved in the membrane, creating a temporary ion-pair complex between the hydrophilic drug and the carrier. As the model analytes were extracted directly into an aqueous solution, there was no need for evaporation of the extract before injection into LC-MS. Hence, the sample preparation is performed in one step. With optimized conditions, the extraction recoveries were in the range 50-89% from human plasma after 45min extraction. The data from the method evaluation were satisfactory and in line with current guidelines, and revealed an extraction method with substantial potential for high throughput bioanalysis of polar basic drugs.

  10. Effect of morphology of mesoporous silica on characterization of protic ionic liquid-based composite membranes

    NASA Astrophysics Data System (ADS)

    Ye, Yun-Sheng; Liang, Gao-Wei; Chen, Bo-Han; Shen, Wei-Chung; Tseng, Chi-Yung; Cheng, Ming-Yao; Rick, John; Huang, Yao-Jheng; Chang, Feng-Chih; Hwang, Bing-Joe

    Effects caused by the morphology of mesoporous silica on the characterization of protic ionic liquid-based composite membranes for anhydrous proton exchange membrane applications are investigated. Two types of SBA15 materials with platelet and fiberlike morphologies are synthesized and incorporated into a mixture of polymerizable monomers together with an ionic liquid (IL) [1-butyl-3-methylimidazolium bis(trifluoromethane sulfone)imide (BMIm-TFSI)] to form new conducting membranes using an in situ photo crosslinking process. Incorporation of a defined amount of fiber-shaped SBA 15 and platelet 15 significantly increases the ionic conductivity to between two and three times that of a plain poly(methyl methacrylate) (PMMA)/IL membrane (2.3 mS cm -1) at 160 °C. The protic ionic liquid (PIL) retention ability of the membranes is increased by the capillary forces introduced by the mesoporous silica materials, while ionic conductivity loss after leaching test is retarded. The highest ionic conductivity (5.3 mS cm -1) is obtained by incorporating 5 wt% of P-SBA 15 in the membrane to about six times that of plain PMMA/IL membrane (0.9 mS cm -1) at 160 °C after leaching test.

  11. The structure of graphene oxide membranes in liquid water, ethanol and water-ethanol mixtures.

    PubMed

    Talyzin, Alexandr V; Hausmaninger, Tomas; You, Shujie; Szabó, Tamás

    2014-01-07

    The structure of graphene oxide (GO) membranes was studied in situ in liquid solvents using synchrotron radiation X-ray diffraction in a broad temperature interval. GO membranes are hydrated by water similarly to precursor graphite oxide powders but intercalation of alcohols is strongly hindered, which explains why the GO membranes are permeated by water and not by ethanol. Insertion of ethanol into the membrane structure is limited to only one monolayer in the whole studied temperature range, in contrast to precursor graphite oxide powders, which are intercalated with up to two ethanol monolayers (Brodie) and four ethanol monolayers (Hummers). As a result, GO membranes demonstrate the absence of "negative thermal expansion" and phase transitions connected to insertion/de-insertion of alcohols upon temperature variations reported earlier for graphite oxide powders. Therefore, GO membranes are a distinct type of material with unique solvation properties compared to parent graphite oxides even if they are composed of the same graphene oxide flakes.

  12. Carbon Dioxide Selective Supported Ionic Liquid Membranes: The Effect of Contaminants

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2008-04-01

    The integrated gasification combined cycle (IGCC) is widely viewed as a promising technology for the large scale production of energy in a carbon constrained world. These cycles, which include gasification, contaminant removal, water-gas shift, CO2 capture and compression, and combustion of the reduced-carbon fuel gas in a turbine, often have significant efficiency advantages over conventional combustion technologies. A CO2 selective membrane capable of maintaining performance at conditions approaching those of low temperature water-gas shift (260oC) could facilitate the production of carbon-neutral energy by simultaneously driving the shift reaction to completion and concentrating CO2 for sequestration. Supported ionic liquid membranes (SILMs) have been previously evaluated for this application and determined to be physically and chemically stable to temperatures in excess of 300oC. These membranes were based on ionic liquids which interacted physically with CO2 and diminished considerably in selectivity at higher temperatures. To alleviate this problem, the original ionic liquids were replaced with ionic liquids able to form chemical complexes with CO2. These complexing ionic liquid membranes have a local maximum in selectivity which is observed at increasing temperatures for more stable complexes. Efforts are currently underway to develop ionic liquids with selectivity maxima at temperatures greater than 75oC, the best result to date, but other practical concerns must also be addressed if the membrane is to be realistically expected to function under water-gas shift conditions. A CO2 selective membrane must function not only at high temperature, but also in the presence of all the reactants and contaminants likely to be present in coal-derived fuel gas, including water, CO, and H2S. A study has been undertaken which examines the effects of each of these gases on both complexing and physically interacting supported liquid membranes. In a joint project

  13. Playing with ionic liquid mixtures to design engineered CO2 separation membranes.

    PubMed

    Tomé, Liliana C; Florindo, Catarina; Freire, Carmen S R; Rebelo, Luís Paulo N; Marrucho, Isabel M

    2014-08-28

    Ionic liquids have been explored as attractive alternative media for CO2 separation not only due to their low volatility but also due to their highly tuneable nature. Aiming at designing highly efficient liquid phases for flue gas separation and natural gas purification, this work focuses on the use of binary ionic liquid mixtures containing sulfate and/or cyano-functionalized anions. Several mixtures were prepared and their gas transport properties through supported ionic liquid membranes (SILMs) were investigated. The thermophysical properties of these mixtures, namely viscosity and density (data presented and discussed in ESI), were also measured so that trends between transport properties and thermophysical properties could be evaluated. The results obtained indicate that depending on the anions mixed, membranes with fine-tuned gas permeabilities, diffusivities and solubilities can be obtained. Additionally, SILMs prepared with these ionic liquid mixtures are on the upper bound of the CO2/N2 separation, or even may surpass it, indicating their potential for separating CO2 in low-pressure post-combustion processes. Overall, the use of ionic liquid mixtures combining the most selective anions with the least viscous anions is a highly promising strategy to design advanced engineered liquid phases for CO2 separation membranes.

  14. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers.

    PubMed

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-07-16

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials -trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems.

  15. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers

    PubMed Central

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-01-01

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials –trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems. PMID:27438837

  16. Template-mediated synthesis of periodic membranes for improved liquid-phase separations

    SciTech Connect

    Groger, H.

    1997-10-01

    Solid/liquid separations of particulates in waste streams will benefit from design and development of ultrafiltration (UF) membranes with uniform, tailorable pore size and chemical, thermal, and mechanical stability. Such membranes will perform solid/liquid separations with high selectivity, permeance, lifetime, and low operating costs. Existing organic and inorganic membrane materials do not adequately meet all these requirements. An innovative solution to the need for improved inorganic membranes is the application of mesoporous ceramics with narrow pore-size distributions and tailorable pore size (1.5 to 10 nm) that have recently been shown to form with the use of organic surfactant molecules and surfactant assemblies as removable templates. This series of porous ceramics, designated MCM-41, consists of silica or aluminosilicates distinguished by periodic arrays of uniform channels. In this Phase I Small Business Innovation Research program, American Research Corporation of Virginia will demonstrate the use of supported MCM-41 thin films deposited by a proprietary technique, as UF membranes. Technical objectives include deposition in thin, defect-free periodic mesoporous MCM-41 membranes on porous supports; measurement of membrane separation factors, permeance, and fouling; and measurement of membrane lifetime as part of an engineering and economic analysis.

  17. Indirect evaporative cooler using membrane-contained, liquid desiccant for dehumidification

    SciTech Connect

    Kozubal, Eric Joseph

    2016-12-13

    An indirect evaporative cooler for cooling inlet supply air from a first temperature to a second, lower temperature using a stream of liquid coolant and a stream of exhaust or purge air. The cooler includes a first flow channel for inlet supply air and a second flow channel adjacent the first for exhaust air. The first and second flow channels are defined in part by sheets of a membrane permeable to water vapor such that mass is transferred as a vapor through the membrane from the inlet supply air to a contained liquid desiccant for dehumidification and also to the exhaust air as heat is transferred from the inlet supply air to the liquid coolant. A separation wall divides the liquid desiccant and the coolant but allows heat to be transferred from the supply air to the coolant which releases water vapor to the counter or cross flowing exhaust air.

  18. Indirect evaporative cooler using membrane-contained, liquid desiccant for dehumidification

    DOEpatents

    Kozubal, Eric Joseph; Slayzak, Steven Joseph

    2014-07-08

    An indirect evaporative cooler for cooling inlet supply air from a first temperature to a second, lower temperature using a stream of liquid coolant and a stream of exhaust or purge air. The cooler includes a first flow channel for inlet supply air and a second flow channel adjacent the first for exhaust air. The first and second flow channels are defined in part by sheets of a membrane permeable to water vapor such that mass is transferred as a vapor through the membrane from the inlet supply air to a contained liquid desiccant for dehumidification and also to the exhaust air as heat is transferred from the inlet supply air to the liquid coolant. A separation wall divides the liquid desiccant and the coolant but allows heat to be transferred from the supply air to the coolant which releases water vapor to the counter or cross flowing exhaust air.

  19. Manipulating lipid membrane architecture by liquid crystal-analog curvature elasticity (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Lee, Sin-Doo

    2015-10-01

    Soft matters such as liquid crystals and biological molecules exhibit a variety of interesting physical phenomena as well as new applications. Recently, in mimicking biological systems that have the ability to sense, regulate, grow, react, and regenerate in a highly responsive and self-adaptive manner, the significance of the liquid crystal order in living organisms, for example, a biological membrane possessing the lamellar order, is widely recognized from the viewpoints of physics and chemistry of interfaces and membrane biophysics. Lipid bilayers, resembling cell membranes, provide primary functions for the transport of biological components of ions and molecules in various cellular activities, including vesicle budding and membrane fusion, through lateral organization of the membrane components such as proteins. In this lecture, I will describe how the liquid crystal-analog curvature elasticity of a lipid bilayer plays a critical role in developing a new platform for understanding diverse biological functions at a cellular level. The key concept is to manipulate the local curvature at an interface between a solid substrate and a model membrane. Two representative examples will be demonstrated: one of them is the topographic control of lipid rafts in a combinatorial array where the ligand-receptor binding event occurs and the other concerns the reconstitution of a ring-type lipid raft in bud-mimicking architecture within the framework of the curvature elasticity.

  20. Conductivity Scaling Relationships in Nanostructured Membranes based on Protic Polymerized Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Sanoja, Gabriel; Lynd, Nathaniel; Segalman, Rachel

    2015-03-01

    Nanostructured membranes based on protic polymerized ionic liquids are of great interest for a variety of electrochemical applications. Understanding the relationship between composition, structure, and ionic conductivity for these materials is essential for designing novel membranes with improved properties. In this work, we explore the effect of volume fraction of ionic liquid on conductivity, σ using a model system composed of poly[isoprene-block-(ethylene oxide-stat-histamine glycidyl ether) diblock copolymers [PI- b - P(EO-stat-HGE)] and the resulting [PI- b - P(EO-stat-IL)] obtained after treatment with trifluoroacetic acid. These materials self-assemble into lamellar structures with volume fractions of ionic liquid ranging from 0.50 to 0.90 as demonstrated by SAXS. PI- b - P(EO-stat-IL) membranes exhibit conductivities up to 4 x 10-3 S/cm at room temperature. In addition, PI- b - P(EO-stat-IL) based membranes have lower water uptake (λ = 8-10) in comparison with most proton conducting membranes reported elsewhere. The low λ in these membranes might translate into a stronger effect of morphology on transport properties. Joint Center for Artificial Photosynthesis.

  1. The myelin proteolipid plasmolipin forms oligomers and induces liquid-ordered membranes in the Golgi complex.

    PubMed

    Yaffe, Yakey; Hugger, Ilan; Yassaf, Inbar Nevo; Shepshelovitch, Jeanne; Sklan, Ella H; Elkabetz, Yechiel; Yeheskel, Adva; Pasmanik-Chor, Metsada; Benzing, Carola; Macmillan, Alexander; Gaus, Katharina; Eshed-Eisenbach, Yael; Peles, Elior; Hirschberg, Koret

    2015-07-01

    Myelin comprises a compactly stacked massive surface area of protein-poor thick membrane that insulates axons to allow fast signal propagation. Increasing levels of the myelin protein plasmolipin (PLLP) were correlated with post-natal myelination; however, its function is unknown. Here, the intracellular localization and dynamics of PLLP were characterized in primary glial and cultured cells using fluorescently labeled PLLP and antibodies against PLLP. PLLP localized to and recycled between the plasma membrane and the Golgi complex. In the Golgi complex, PLLP forms oligomers based on fluorescence resonance energy transfer (FRET) analyses. PLLP oligomers blocked Golgi to plasma membrane transport of the secretory protein vesicular stomatitis virus G protein (VSVG), but not of a VSVG mutant with an elongated transmembrane domain. Laurdan staining analysis showed that this block is associated with PLLP-induced proliferation of liquid-ordered membranes. These findings show the capacity of PLLP to assemble potential myelin membrane precursor domains at the Golgi complex through its oligomerization and ability to attract liquid-ordered lipids. These data support a model in which PLLP functions in myelin biogenesis through organization of myelin liquid-ordered membranes in the Golgi complex.

  2. An adaptive self-healing ionic liquid nanocomposite membrane for olefin-paraffin separations.

    PubMed

    Pitsch, Fee; Krull, Florian F; Agel, Friederike; Schulz, Peter; Wasserscheid, Peter; Melin, Thomas; Wessling, Matthias

    2012-08-16

    An adaptive self-healing ionic liquid nanocomposite membrane comprising a multi-layer support structure hosting the ionic salt [Ag](+) [Tf(2) N](-) is used for the separation of the olefin propylene and the paraffin propane. The ionic salt renders liquid like upon complexation with propylene, resulting in facilitated transport of propylene over propane at benchmark-setting selectivity and permeance levels. The contacting with acetylene causes the ionic salt to liquefy without showing evidence of forming explosive silver acetylide.

  3. Liquid-Feed Methanol Fuel Cell With Membrane Electrolyte

    NASA Technical Reports Server (NTRS)

    Surampudi, Subbarao; Narayanan, S. R.; Halpert, Gerald; Frank, Harvey; Vamos, Eugene

    1995-01-01

    Fuel cell generates electricity from direct liquid feed stream of methanol/water solution circulated in contact with anode, plus direct gaseous feed stream of air or oxygen in contact with cathode. Advantages include relative simplicity and elimination of corrosive electrolytic solutions. Offers potential for reductions in size, weight, and complexity, and for increases in safety of fuel-cell systems.

  4. A model for a liquid membrane separation stage

    SciTech Connect

    1997-02-01

    The coupled mixer-settlers having a common settling zone suggested for use to extract fission products from a conversion reactor blanket are analogues of membrane apparatuses and at a first glance in terms of hydrodynamics do not differ from conventional mixer-settlers. However, the common settling zone complicates both the design solutions and their modelling. For example, different emulsion types can result in mixers and it is not known how this fact will affect phenomena such as separation rates, disperse phase entrainment under conditions close to flooding. For initial studies of the feasibility of the process in principle and the primary optimization of the structure of the transfer scheme one needs to have a model and a program to calculate the statics of a multistage membrane facility of this type.

  5. Effect of choline carboxylate ionic liquids on biological membranes.

    PubMed

    Rengstl, Doris; Kraus, Birgit; Van Vorst, Matthew; Elliott, Gloria D; Kunz, Werner

    2014-11-01

    Choline carboxylates, ChCm, with m=2-10 and choline oleate are known as biocompatible substances, yet their influence on biological membranes is not well-known, and the effect on human skin has not previously been investigated. The short chain choline carboxylates ChCm with m=2, 4, 6 act as hydrotropes, solubilizing hydrophobic compounds in aqueous solution, while the longer chain choline carboxylates ChCm with m=8, 10 and oleate are able to form micelles. In the present study, the cytotoxicity of choline carboxylates was tested using HeLa and SK-MEL-28 cells. The influence of these substances on liposomes prepared from dipalmitoylphosphatidylcholine (DPPC) was also evaluated to provide insights on membrane interactions. It was observed that the choline carboxylates with a chain length of m>8 distinctly influence the bilayer, while the shorter ones had minimal interaction with the liposomes.

  6. Catalytic membrane reactor for conversion of syngas to liquid hydrocarbons

    SciTech Connect

    Khassin, A.A.

    2005-07-01

    Plug-through catalytically-active contractor membranes can combine high permeability ({gt} 20 m Darcy), high mechanical strength ({gt} 20 kg cm{sup -2}) and high heat-conductivity ({gt} 4 W(mK){sup -1}). Therefore, it provides isothermicity and low pressure drop. The intense mass-transfer within transport pores, high specific area of these pores and small distances between two adjacent transport pores weaken the mass-transfer constraints. Using the PCM one can achieve high space time yield of hydrocarbons and high selectivity towards heavy hydrocarbons and olefins. These advantages allow supposing the effective usage of the PCM catalytic membrane reactors in Fischer-Tropsch synthesis. Also the same approach could be efficient for some other multiphase catalytic processes, like hydrogenation of the unsaturated fatty acids. 5 figs.

  7. Concentration of radioactive liquid streams by membrane processes

    SciTech Connect

    Ramachandhran, V.; Misra, B.M.

    1983-05-01

    The possibility of concentrating radioactive effluents by reverse osmosis was investigated. Cellulose acetate membranes of the Loeb-Sourirajan type were used, and their performance was evaluated the CsCl and SrCl/sub 2/ solutions in concentrations ranging from millimolar to trace level. The applicability of solution-diffusion and irreversible thermodynamic models for predicting solute separation in the above concentration range has been investigated. Some aspects of the selectivity with reference to trace radionuclides are also reported.

  8. Diffusion coefficient of an inclusion in a liquid membrane supported by a solvent of arbitrary thickness.

    PubMed

    Seki, Kazuhiko; Ramachandran, Sanoop; Komura, Shigeyuki

    2011-08-01

    The diffusion coefficient of an inclusion in a liquid membrane is investigated by taking into account the interaction between membranes and bulk solvents of arbitrary thickness. As illustrative examples, the diffusion coefficients of two types of inclusions, a circular domain composed of fluid with the same viscosity as the host membrane and that of a polymer chain embedded in the membrane, are studied. The diffusion coefficients are expressed in terms of the hydrodynamic screening lengths, which vary according to the solvent thickness. When the membrane fluid is dragged by the solvent of finite thickness, via stick boundary conditions, multiple hydrodynamic screening lengths together with the weight factors to the diffusion coefficients are obtained from the characteristic equation. The conditions for which the diffusion coefficients can be approximated by the expression including only a single hydrodynamic screening length are also shown.

  9. Low-voltage electrochemically stimulated stir membrane liquid-liquid microextraction as a novel technique for the determination of methadone.

    PubMed

    Ara, Katayoun Mahdavi; Raofie, Farhad

    2017-06-01

    In the present work, for the first time, a new portable setup was designed, developed and presented for the extraction of methadone, as a basic drug model from biological fluid samples using a low-voltage electrically stimulated stir membrane liquid-liquid microextraction technique (LV-ESSM-LLME), followed by high-performance liquid chromatography with ultraviolet detection. This new approach combines the advantages of stir membrane liquid-liquid microextraction and electrokinetic migration in the same unit under soft electrochemical conditions in a portable device, allowing for the isolation and preconcentration of the target analyte in a simple and efficient manner under three-phase mode. To investigate the influence of external stirring and the application of electrical potential as the driving force, a comparative study of all variables involved in the extraction process was carried out using the low-voltage electromembrane extraction (LV-EME) and LV-ESSM-LLME methods. Under soft electrokinetic migration conditions, methadone was transported from an acidic sample solution (pH 4.0), through the NPOE immobilized in the pores of the porous polypropylene sheet membrane, and into 25µL of 10mmolL(-1) HCl acceptor solution with a stirring rate of 1000rpm and 700rpm after 15min and 20min for LV-ESSM-LLME and LV-EME, respectively. Under the optimized conditions, preconcentration factors in the range of 17-24 and 21.5-29 for LV-EME and LV-ESSM-LLME, respectively, were considered, and satisfactory repeatability (4.5<[RSD]<7.5) was obtained in different matrices. The obtained relative recoveries of the target analyte were in the range of 87-94% and 93-101% for LV-EME and LV-ESSM-LLME, respectively, which indicated the excellent capability of the developed methods to extract methadone from complex matrices.

  10. Ion-selective supported liquid membranes placed under steady-state diffusion control.

    PubMed

    Tompa, Károly; Birbaum, Karin; Malon, Adam; Vigassy, Tamás; Bakker, Eric; Pretsch, Ernö

    2005-12-01

    Supported liquid membranes are used here to establish steady-state concentration profiles across ion-selective membranes rapidly and reproducibly. This opens up new avenues in the area of nonequilibrium potentiometry, where reproducible accumulation and depletion processes at ion-selective membranes may be used to gain valuable analytical information about the sample. Until today, drifting signals originating from a slowly developing concentration profile across the ion-selective membrane made such approaches impractical in zero current potentiometry. Here, calcium- and silver-selective membranes were placed between two identical aqueous electrolyte solutions, and the open circuit potential was monitored upon changing the composition of one solution. Steady state was reached in approximately 1 min with 25-microm porous polypropylene membranes filled with bis(2-ethylhexyl) sebacate doped with ionophore and lipophilic ion exchanger. Ion transport across the membrane resulted on the basis of nonsymmetric ion-exchange processes at both membrane sides. The steady-state potential was calculated as the sum of the two membrane phase boundary potentials, and good correspondence to experiment was observed. Concentration polarizations in the contacting aqueous phases were confirmed with stirring experiments. It was found that interferences (barium in the case of calcium electrodes and potassium with silver electrodes) induce a larger potential change than expected with the Nicolsky equation because they influence the level of polarization of the primary ion (calcium or silver) that remains potential determining.

  11. Dynamics of a Room Temperature Ionic Liquid in Supported Ionic Liquid Membranes vs the Bulk Liquid: 2D IR and Polarized IR Pump-Probe Experiments.

    PubMed

    Shin, Jae Yoon; Yamada, Steven A; Fayer, Michael D

    2017-01-11

    Supported ionic liquid membranes (SILMs) are membranes that have ionic liquids impregnated in their pores. SILMs have been proposed for advanced carbon capture materials. Two-dimensional infrared (2D IR) and polarization selective IR pump-probe (PSPP) techniques were used to investigate the dynamics of reorientation and spectral diffusion of the linear triatomic anion, SeCN(-), in poly(ether sulfone) (PES) membranes and room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf2). The dynamics in the bulk EmimNTf2 were compared to its dynamics in the SILM samples. Two PES membranes, PES200 and PES30, have pores with average sizes, ∼300 nm and ∼100 nm, respectively. Despite the relatively large pore sizes, the measurements reveal that the reorientation of SeCN(-) and the RTIL structural fluctuations are substantially slower in the SILMs than in the bulk liquid. The complete orientational randomization, slows from 136 ps in the bulk to 513 ps in the PES30. 2D IR measurements yield three time scales for structural spectral diffusion (SSD), that is, the time evolution of the liquid structure. The slowest decay constant increases from 140 ps in the bulk to 504 ps in the PES200 and increases further to 1660 ps in the PES30. The results suggest that changes at the interface propagate out and influence the RTIL structural dynamics even more than a hundred nanometers from the polymer surface. The differences between the IL dynamics in the bulk and in the membranes suggest that studies of bulk RTIL properties may be poor guides to their use in SILMs in carbon capture applications.

  12. SUPPORTED LIX-84 LIQUID MEMBRANES FOR METAL ION SEPARATION: A STUDY ON METAL ION SORPTION EQUILIBRIUM AND KINETICS

    EPA Science Inventory

    Supported 2-hydroxy-5-nonyl-acetophenone oxime (LIX-84) liquid membranes have potential applications for the removal (or recovery) of copper ions from waste streams. But, the stability of such a liquid membrane remains the major hurdle for its practical applications. Inorganic su...

  13. Enhanced ionic liquid mobility induced by confinement in 1D CNT membranes.

    PubMed

    Berrod, Q; Ferdeghini, F; Judeinstein, P; Genevaz, N; Ramos, R; Fournier, A; Dijon, J; Ollivier, J; Rols, S; Yu, D; Mole, R A; Zanotti, J-M

    2016-04-21

    Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators.

  14. Flow ozonolysis using a semipermeable Teflon AF-2400 membrane to effect gas-liquid contact.

    PubMed

    O'Brien, Matthew; Baxendale, Ian R; Ley, Steven V

    2010-04-02

    A flow-through chemistry apparatus has been developed which allows gases and liquids to contact via a semipermeable Teflon AF-2400 membrane. In this preliminary investigation, the concept was proven by application to the ozonolysis of a series of alkenes.

  15. ASSESSMENT OF LIQUID EMULSION MEMBRANE FOR CLEAN UP OF AQUEOUS WASTE EFFLUENTS FROM HAZARDOUS ELEMENTS

    SciTech Connect

    El-Reefy, Sohair A.; Selim, Y.T.; Hassan, M.A.; Aly, H.F.

    2003-02-27

    Four liquid emulsion membrane (LEM) systems are given to remove different hazardous elements such as uranium, thorium, cobalt, copper, lead, and cadmium from different aqueous waste effluents. The optimum conditions for use of these systems are deduced. The potentiality of LEM for removal of hazardous pollutants from aqueous waste solutions is given.

  16. Flexible and Actuating Nanoporous Poly(ionic liquids)-paper based Hybrid Membranes.

    PubMed

    Lin, Huijuan; Gong, Jiang; Miao, Han; Guterman, Ryan; Song, Hao-Jie; Zhao, Qiang; Dunlop, John W C; Yuan, Jiayin

    2017-04-04

    Porous and flexible actuating materials are important in the development of smart systems. We report here a facile method to prepare scalable, flexible actuating porous membranes based on a poly(ionic liquid)-modified tissue paper. The targeted membrane property profile was based on a synergy of a gradient porous structure of poly(ionic liquid) network and the flexibility of tissue paper. The gradient porous structure was built up through ammonia-triggered electrostatic complexation of a poly(ionic liquid) with poly(acrylic acid) (PAA) that were previously impregnated inside the tissue paper. As a result, these porous membranes undergo bending deformation in response to organic solvents in vapor or liquid phase and can recover their shape back in air, which was demonstrated to be able to serve as solvent sensors. Besides, they show enhanced mechanical properties due to the introduction of mechanically flexible tissue paper that allows the membranes to be designed as new responsive textiles and contractile actuators.

  17. Impact of ionic liquids in aqueous solution on bacterial plasma membranes studied with molecular dynamics simulations.

    PubMed

    Lim, Geraldine S; Zidar, Jernej; Cheong, Daniel W; Jaenicke, Stephan; Klähn, Marco

    2014-09-04

    The impact of five different imidazolium-based ionic liquids (ILs) diluted in water on the properties of a bacterial plasma membrane is investigated using molecular dynamics (MD) simulations. Cations considered are 1-octyl-3-methylimidazolium (OMIM), 1-octyloxymethyl-3-methylimidazolium (OXMIM), and 1-tetradecyl-3-methylimidazolium (TDMIM), as well as the anions chloride and lactate. The atomistic model of the membrane bilayer is designed to reproduce the lipid composition of the plasma membrane of Gram-negative Escherichia coli. Spontaneous insertion of cations into the membrane is observed in all ILs. Substantially more insertions of OMIM than of OXMIM occur and the presence of chloride reduces cation insertions compared to lactate. In contrast, anions do not adsorb onto the membrane surface nor diffuse into the bilayer. Once inserted, cations are oriented in parallel to membrane lipids with cation alkyl tails embedded into the hydrophobic membrane core, while the imidazolium-ring remains mostly exposed to the solvent. Such inserted cations are strongly associated with one to two phospholipids in the membrane. The overall order of lipids decreased after OMIM and OXMIM insertions, while on the contrary the order of lipids in the vicinity of TDMIM increased. The short alkyl tails of OMIM and OXMIM generate voids in the bilayer that are filled by curling lipids. This cation induced lipid disorder also reduces the average membrane thickness. This effect is not observed after TDMIM insertions due to the similar length of cation alkyl chain and the fatty acids of the lipids. This lipid-mimicking behavior of inserted TDMIM indicates a high membrane affinity of this cation that could lead to an enhanced accumulation of cations in the membrane over time. Overall, the simulations reveal how cations are inserted into the bacterial membrane and how such insertions change its properties. Moreover, the different roles of cations and anions are highlighted and the fundamental

  18. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 2, December 21, 1989--March 20, 1990

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  19. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 8, June 21, 1991--September 20, 1991

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will also be investigated.

  20. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 7, March 21, 1991--June 20, 1991

    SciTech Connect

    Tsotsis, T.T.

    1992-06-19

    Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  1. Basic technology for 6Li enrichment using an ionic-liquid impregnated organic membrane

    NASA Astrophysics Data System (ADS)

    Hoshino, Tsuyoshi; Terai, Takayuki

    2011-10-01

    The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ( 6Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% 6Li. In this paper, a new lithium isotope separation technique using an ionic-liquid impregnated organic membrane is proposed. In order to separate and concentrate lithium isotopes, only lithium ions are able to move through the membrane by electrodialysis between the cathode and the anode in lithium solutions. Preliminary experiments of lithium isotope separation were conducted using this phenomenon. Organic membranes impregnated with TMPA-TFSI and PP13-TFSI as ionic liquids were prepared, and the relationship between the 6Li separation coefficient and the applied electrodialytic conditions was evaluated using them. The results showed that the 6Li isotope separation coefficient in this method (about 1.1-1.4) was larger than that in the mercury amalgam method (about 1.06).

  2. Synthesis of Pyrrolidinium-type Poly(Ionic Liquid) Membranes for Antibacterial Applications.

    PubMed

    Qin, Jing; Guo, Jiangna; Xu, Qiming; Zheng, Zhiqiang; Mao, Hailei; Yan, Feng

    2017-03-08

    Pyrrolidinium-type small molecule ionic liquids (ILs), poly(ionic liquid) (PIL) homopolymers, and their corresponding PIL membranes were synthesized and used for antibacterial applications. The influences of substitutions at the N position of pyrrolidinium cation on the antimicrobial activities against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were studied by minimum inhibitory concentration (MIC). The antibacterial efficiency of both the small molecule ILs and PIL homopolymers increased with the increase of the alkyl chain length of substitutions. Furthermore, PIL homopolymers show relatively lower MIC values, indicating better antimicrobial activities than those of corresponding small molecule ILs. However, the antibacterial properties of the PIL membranes are contrary to corresponding ILs and PIL homopolymers, which reducing with the increase of alkyl chain length. Furthermore, the resultant PIL membranes show excellent hemocompatibility and low cytotoxicity towards human cells, demonstrating clinical feasibility in topical applications.

  3. Liquid membranes. January 1970-August 1989 (Citations from the COMPENDEX data base). Report for January 1970-August 1989

    SciTech Connect

    Not Available

    1989-10-01

    This bibliography contains citations concerning the development and utilization of liquid membranes and liquid-membrane process techniques. Topics include ion-transport properties of membranes, modeling studies, and investigations of potential distribution and diffusion phenomena. Applications include medicine, gas separation, biochemisty, metals separation and recovery, waste water treatment, and solute extraction. (This updated bibliography contains 296 citations, 214 of which are new entries to the previous edition.)

  4. Mechanism of proton transport in ionic-liquid-doped perfluorosulfonic acid membranes.

    PubMed

    Kumar, Milan; Venkatnathan, Arun

    2013-11-21

    Ionic-liquid-doped perfluorosulfonic acid membranes (PFSA) are promising electrolytes for intermediate/high-temperature fuel cell applications. In the present study, we examine proton-transport pathways in a triethylammonium-triflate (TEATF) ionic liquid (IL)-doped Nafion membrane using quantum chemistry calculations. The IL-doped membrane matrix contains triflic acid (TFA), triflate anions (TFA(-)), triethylamine (TEA), and triethylammonium cations (TEAH(+)). Results show that proton abstraction from the sulfonic acid end groups in the membrane by TFA(-) facilitates TEAH(+) interaction with the side-chains. In the IL-doped PFSA membrane matrix, proton transfer from TFA to TEA and TFA to TFA(-) occurs. However, proton transfer from a tertiary amine cation (TEAH(+)) to a tertiary amine (TEA) does not occur without an interaction with an anion (TFA(-)). An anion interaction with the amine increases its basicity, and as a consequence, it takes a proton from a cation either instantly (if the cation is freely moving) or with a small activation energy barrier of 2.62 kcal/mol (if the cation is interacting with another anion). The quantum chemistry calculations predict that anions are responsible for proton-exchange between cations and neutral molecules of a tertiary amine. Results from this study can assist the experimental choice of IL to provide enhanced proton conduction in PFSA membrane environments.

  5. Actin Skeletons at the Membrane as Liquid Crystal Elastomers

    NASA Astrophysics Data System (ADS)

    Discher, Dennis; Dalhaimer, Paul; Levine, Alex; Lubensky, Tom

    2002-03-01

    Actin filaments crosslinked by proteins such as spectrin form plasma membrane networks in a number of cell-types, including the red blood cell and the outer hair cell of the inner ear. Actin filaments are stiff compared to spectrin and can be considered hard rods. We statistically simulate network phase behavior at finite temperature by Monte Carlo methods, and explore the effects of spectrin and actin length as well as isotropic and shear stresses. Relative lengths required for a zero pressure nematic phase are determined, for exmaple, and indicate structural requirements for obtaining a 2D anisotropic elastomer. Emerging studies of network elasticity examine the anisotropic state and begin to probe the relevance of hyper-soft modes to hearing.

  6. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 12, June 21, 1992--September 20, 1992

    SciTech Connect

    Tsotsis, T.T.

    1992-12-31

    In this project we intend to study a novel process concept, i.e.,the use of ceramic membranes reactors in upgrading of coal derived liquids. Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. They have, furthermore, the inherent capability for combining reaction and separation in a single step. Thus they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, as those typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we wig evaluate the performance of Sel-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  7. High temperature ceramic membrane reactors for coal liquid upgrading. Quarter report No. 9, September 21, 1991--December 20, 1991

    SciTech Connect

    Tsotsis, T.T.

    1992-07-01

    In this project we intend to study a novel process concept, i.e, the use of ceramic membranes reactors in upgrading of coal derived liquids. Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. They have, furthermore, the inherent capability for combining reaction and separation in a single step. Thus they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, as those typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. In this project we will evaluate the performance of Sol-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. In addition, the development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  8. Liquid-liquid-solid microextraction and detection of nerve agent simulants by on-membrane Fourier transform infrared spectroscopy.

    PubMed

    Garg, Prabhat; Purohit, Ajay; Tak, Vijay K; Kumar, Ajeet; Dubey, D K

    2012-11-02

    A coupling of novel liquid-liquid-solid microextraction (LLSME) technique based on porous hydrophobic membrane and Fourier-transform infrared spectroscopy has been presented for the detection, identification and quantification of markers and simulants of nerve agents. Two isomers O,O'-dihexyl methylphosphonate (DHMP) and O,O'-dipentyl isopropylphosphonate (DPIPP) were chosen as model analytes for the study. In the present technique, organic phase was immobilised within the pores of membrane after fixing it in an assembly, which was then immersed into aqueous sample of target analytes for extraction. The analytes were directly determined on the surface of membrane by FTIR spectroscopy without elution. On comparison with solid phase microextraction (SPME), LLSME was found to be much more efficient. The method was optimised and quantitative analyses were performed using calibration curves obtained via Beer's law and employing processing of spectra obtained, via a multivariate calibration technique partial least square (PLS). Relative standard deviations (RSDs) for intraday repeatability and interday reproducibility were found to be in the range of 0.20-0.50% and 0.20-0.60%, respectively. Limit of detection (LOD) was achieved up to 15 ng mL(-1). Applicability of the method was tested with an unknown real sample obtained in an international official proficiency test (OPT).

  9. Stir-membrane solid-liquid-liquid microextraction for the determination of parabens in human breast milk samples by ultra high performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Rodríguez-Gómez, Rocío; Roldán-Pijuán, Mercedes; Lucena, Rafael; Cárdenas, Soledad; Zafra-Gómez, Alberto; Ballesteros, Oscar; Navalón, Alberto; Valcárcel, Miguel

    2014-08-08

    In this article, stir-membrane solid-liquid-liquid microextraction (SM-SLLME) is tailored for the analysis of solid matrices and it has been evaluated for the determination of parabens in l breast milk samples. A three-phase microextraction mode was used for the extraction of the target compounds taking advantage of their acid-base properties. The unit allows the simultaneous extraction of the target compounds from the solid sample to an organic media and the subsequent transference of the analytes to an aqueous acceptor phase. The method includes the identification and quantification of the analytes by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). All the variables involved in the extraction procedure have been accurately studied and optimized. The analytes were detected and quantified using a triple quadrupole mass spectrometer (QqQ). The selection of two specific fragmentation transitions for each compound allowed simultaneous quantification and identification. The method has been analytically characterized on the basis of its linearity, sensitivity and precision. Limits of detection ranged from 0.1 to 0.2ngmL(-1) with precision better than 8%, (expressed as relative standard deviation). Relative recoveries were in the range from 91 to 106% which demonstrated the applicability of the stir-membrane solid-liquid-liquid microextraction for the proposed analytical problem. Moreover, the method has been satisfactorily applied for the determination of parabens in lyophilized breast milk samples from 10 randomly selected individuals.

  10. Oxygen-selective immobilized liquid membranes for operation of lithium-air batteries in ambient air

    SciTech Connect

    Zhang, Jian; Xu, Wu; Liu, Wei

    2010-11-01

    In this paper, nonaqueous-electrolyte-based Li-air batteries with O2-selective immobilized liquid membranes have been developed and operated in ambient air with 20~30% relative humidity(RH). Continuous anhydrous O2 can be supplied from the ambient through a membrane barrier layer at interface of the cathode and ambient air. The membranes allow O2 permeate through while blocking moisture. These membranes were prepared by loading O2-selective liquid fluids such as silicone oils into porous supports such as porous metal sheets and Teflon (PTFE) films. It was found that silicone oil of high viscosity shows better performance. The membrane performance was not affected by the oil loading temperature. The immobilized silicone oil (viscosity 100,000cst) membrane in porous PTFE film enabled the Li-air batteries with Ketjen black carbon air electrodes to operate in ambient air (with 20% RH) for 16.3 days with a specific capacity of 789 mAh/g carbon and a specific energy of 2182 Wh/kg carbon. Its performance is much better than reference battery assembled with the same battery material but by use of a commercial, porous PTFE diffusion membranes as the moisture barrier layer on the cathode, which only had a discharge time of 5.5 days corresponding to a specific capacity of 267 mAh/g carbon and a specific energy of 704 Wh/kg carbon. The Li-air battery with the present selective membrane barrier layer even showed better performance in ambient air operation (20% RH) than the reference battery tested in the dry air box (< 1% RH).

  11. Lithium-Ion-Conducting Electrolytes: From an Ionic Liquid to the Polymer Membrane

    PubMed Central

    Fernicola, A.; Weise, F. C.; Greenbaum, S. G.; Kagimoto, J.; Scrosati, B.; Soleto, A.

    2009-01-01

    This work concerns the design, the synthesis, and the characterization of the N-butyl-N-ethylpiperidinium N,N-bis(trifluoromethane)sulfonimide (PP24TFSI) ionic liquid (IL). To impart Li-ion transport, a suitable amount of lithium N,N-bis-(trifluoromethane)sulfonimide (LiTFSI) is added to the IL. The Li–IL mixture displays ionic conductivity values on the order of 10−4 S cm−1 and an electrochemical stability window in the range of 1.8–4.5 V vs Li+/Li. The voltammetric analysis demonstrates that the cathodic decomposition gives rise to a passivating layer on the surface of the working electrode, which kinetically extends the stability of the Li/IL interface as confirmed by electrochemical impedance spectroscopy measurements. The LiTFSI–PP24TFSI mixture is incorporated in a poly(vinylidene fluoride-co-hexafluoropropylene) matrix to form various electrolyte membranes with different LiTFSI–PP24TFSI contents. The ionic conductivity of all the membranes resembles that of the LiTFSI–IL mixture, suggesting an ionic transport mechanism similar to that of the liquid component. NMR measurements demonstrate a reduction in the mobility of all ions following the addition of LiTFSI to the PP24TFSI IL and when incorporating the mixture into the membrane. Finally, an unexpected but potentially significant enhancement in Li transference number is observed in passing from the liquid to the membrane electrolyte system. PMID:20354582

  12. Gas-liquid interfacial plasmas producing reactive species for cell membrane permeabilization

    PubMed Central

    Kaneko, Toshiro; Sasaki, Shota; Takashima, Keisuke; Kanzaki, Makoto

    2017-01-01

    Gas-liquid interfacial atmospheric-pressure plasma jets (GLI-APPJ) are used medically for plasma-induced cell-membrane permeabilization. In an attempt to identify the dominant factors induced by GLI-APPJ responsible for enhancing cell-membrane permeability, the concentration and distribution of plasma-produced reactive species in the gas and liquid phase regions are measured. These reactive species are classified in terms of their life-span: long-lived (e.g., H2O2), short-lived (e.g., O2•−), and extremely-short-lived (e.g., •OH). The concentration of plasma-produced •OHaq in the liquid phase region decreases with an increase in solution thickness (<1 mm), and plasma-induced cell-membrane permeabilization is found to decay markedly as the thickness of the solution increases. Furthermore, the horizontally center-localized distribution of •OHaq, resulting from the center-peaked distribution of •OH in the gas phase region, corresponds with the distribution of the permeabilized cells upon APPJ irradiation, whereas the overall plasma-produced oxidizing species such as H2O2aq in solution exhibit a doughnut-shaped horizontal distribution. These results suggest that •OHaq is likely one of the dominant factors responsible for plasma-induced cell-membrane permeabilization. PMID:28163376

  13. Synthesis and characterization of ionic liquid (EMImBF4)/Li+ - chitosan membranes for ion battery

    NASA Astrophysics Data System (ADS)

    Pasaribu, Marvin H.; Arcana, I. Made; Wahyuningrum, Deana

    2015-09-01

    Lithium ion battery has been currently developed and produced because it has a longer life time, high energycapacity, and the efficient use of lithium ion battery that is suitable for storing electrical energy. However, this battery has some drawbacks such as use liquid electrolytes that are prone to leakage and flammability during the battery charging process in high temperature. In this study, an ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) containing Li+ ions was synthesized and combined with chitosan polymer host as a polymer electrolyte membrane for lithium-ion batteries to solve this problems. This ionic liquid was obtained from the anion metathesis reaction between EMImBr and LiBF4 salt, while EMImBr was synthesized from the reaction between 1-methylimidazole and ethyl bromide utilizing Microwave Assisted Organic Synthesis (MAOS) method. The ionic liquid obtained was characterized by microstructure analysis with using NMR and FTIR spectroscopy. The polymer electrolyte membrane was characterized by analysis functional groups (FTIR), ionic conductivity (EIS), and surface morphology (SEM). The analysis results of ion conductivity by the EIS method showed the increase the ionic conductivity value of membranes from 1.30 × 10-2 S cm- 1 for chitosan to 1.30 × 10-2 S cm-1 for chitosan with EMImBF4/Li+, and this result was supported by analysis the surface morphology (SEM).

  14. Constructing Ionic Liquid-Filled Proton Transfer Channels within Nanocomposite Membrane by Using Functionalized Graphene Oxide.

    PubMed

    Wu, Wenjia; Li, Yifan; Chen, Pingping; Liu, Jindun; Wang, Jingtao; Zhang, Haoqin

    2016-01-13

    Herein, nanocomposite membranes are fabricated based on functionalized graphene oxides (FGOs) and sulfonated poly(ether ether ketone) (SPEEK), followed by being impregnated with imidazole-type ionic liquid (IL). The functional groups (acidic group or basic group) on FGOs generate strong interfacial interactions with SPEEK chains and then adjust their motion and stacking. As a result, the nanocomposite membranes possess tunable interfacial domains as determined by its free volume characteristic, which provides regulated location for IL storage. The stored ILs act as hopping sites for water-free proton conduction along the FGO-constructed interfacial channels. The microstructure at SPEEK-FGO interface governs the IL uptake and distribution in nanocomposite membrane. Different from GO and vinyl imidazole functionalized GO (VGO), the presence of acidic (-SO3H) groups confers the p-styrenesulfonic acid functionalized GO (SGO) incorporated nanocomposite membrane loose interface and strong electrostatic attraction with imidazole-type IL, imparting an enhanced IL uptake and anhydrous proton conductivity. Nanocomposite membrane containing 7.5% SGO attains the maximum IL uptake of 73.7% and hence the anhydrous conductivity of 21.9 mS cm(-1) at 150 °C, more than 30 times that of SPEEK control membrane (0.69 mS cm(-1)). In addition, SGOs generate electrostatic attractions to the ILs confined within SGO-SPEEK interface, affording the nanocomposite membrane enhanced IL retention ability.

  15. Permeation liquid membrane as a tool for monitoring bioavailable Pb in natural waters.

    PubMed

    Slaveykova, Vera I; Parthasarathy, Nalini; Buffle, Jacques; Wilkinson, Kevin J

    2004-07-26

    In order to predict metal bioavailability by microorganisms in natural waters, analytical speciation techniques such as the permeation liquid membrane (PLM) are required. A planar sheet PLM has been characterized by measuring Pb fluxes in the absence and presence of tiron and nitrilotriacetic, iminodiacetic, malonic, citric, polyacrylic and fulvic (Suwannee River fulvic, SRFA) acids. Important parameters such as the diffusion coefficient in the membrane phase and the effective distribution coefficient between the solution and membrane were evaluated in order to determine limiting conditions for the overall transport flux through the membrane. Subsequently, the PLM was tested for its ability to predict bioavailability by the freshwater alga, Chlorella kesslerii by comparing Pb PLM fluxes (JPLM) to Pb biouptake fluxes (Jint) in the absence and presence of the synthetic ligands and SRFA. The capability of the PLM to mimic transport across biological membranes was demonstrated, in particular, from the similarity between the accumulated (PLM, algal) Pb vs. time plots under the different conditions. Under membrane transport limiting conditions, fluxes across both the PLM and biological membranes were proportional to the free metal ion and directly correlated to each other in the zone below saturation of the biological metal uptake sites. The correlation between the different fluxes may be used to predict Pb uptake by C. kesslerii in the presence of the synthetic ligands. However, in the presence of SRFA, the observed Jint was much higher than predicted by results obtained either in the absence or presence of the synthetic ligands.

  16. Polymer Electrolyte Fuel Cells Membrane Hydration by Direct Liquid Water Contact

    SciTech Connect

    Wilson, M.S.; Zawodzinski, C.; Gottesfeld, S.

    1998-11-01

    An effective means of providing direct liquid hydration of the membrane tends to improve performance particularly of cells with thicker membranes or at elevated temperatures. Supplying the water to the membrane from the anode flow-field through the anode backing via wicks would appear to have advantages over delivering the water through the thickness of the membrane with regards to the uniformity and stability of the supply and the use of off-the-shelf membranes or MEAs. In addition to improving cell performance, an important contribution of direct liquid hydration approaches may be that the overall fuel cell system becomes simpler and more effective. The next steps in the evolution of this approach are a demonstration of the effectiveness of this technique with larger active area cells as well as the implementation of an internal flow-field water reservoir (to eliminate the injection method). Scale-up to larger cell sizes and the use of separate water channels within the anode flow-field is described.

  17. Preparation and characterization of nonaqueous proton-conducting membranes with protic ionic liquids.

    PubMed

    Lu, Fei; Gao, Xinpei; Yan, Xiaojun; Gao, Hejun; Shi, Lijuan; Jia, Han; Zheng, Liqiang

    2013-08-14

    Hybrid Nafion membranes were successfully fabricated by incorporating with protic imidazolium ionic liquids 1-(2-aminoethyl)-3-methylimidazolium chloride ([MimAE]Cl), 1-(2-hydroxylethyl)-3-methylimidazolium chloride ([MimHE]Cl), and 1-carboxylmethyl-3-methylimidazolium chloride ([MimCM]Cl) for high-temperature fuel cells. The composite membranes were characterized by impedance spectroscopy, small-angle X-ray scattering (SAXS), scanning electronic microscopy (SEM), and thermogravimetric analysis (TGA). The incorporated protic ionic liquids enhance the doping of phosphoric acid (PA) and result in a relatively high ionic conductivity. The Nafion/10 wt % [MimAE]Cl/PA composite membrane exhibits an ionic conductivity of 6.0 mS/cm at 130 °C without humidification. [MimAE]Cl can swell the Nafion matrix more homogeneously than [MimHE]Cl or [MimCM]Cl, which results in a better ionic conductivity. It is notable that the composite Nafion/IL/PA membranes have a better thermal stability than the pristine Nafion membranes.

  18. Gramicidin Peptides Alter Global Lipid Compositions and Bilayer Thicknesses of Coexisting Liquid-Ordered and Liquid-Disordered Membrane Domains.

    PubMed

    Hassan-Zadeh, Ebrahim; Hussain, Fazle; Huang, Juyang

    2017-04-04

    Effects of adding 1 mol % of gramicidin-A on the biochemical properties of coexisting liquid-ordered and liquid-disordered (Lo + Ld) membrane domains were investigated. Quaternary giant unilamellar vesicles (GUV) of di18:1PC(DOPC)/di18:0PC(DSPC)/cholesterol/gramicidin-A were prepared using our recently developed damp-film method. The phase boundary of Lo + Ld coexisting region was determined using video fluorescence microscopy. Through fitting Nile Red fluorescence emission spectra, the thermodynamic tie-lines in the Lo + Ld two-phase region were determined. We found that at 1 mol % (i.e., ∼7% of membrane area), gramicidin peptides alter the phase boundary and thermodynamic tie-lines. Gramicidin abolishes the coexisting phases at some lipid compositions but induces phase separation at others. Previous studies of gramicidin emphasize the local perturbation of bilayer thickness adjacent to the protein through the interaction of "hydrophobic mismatch". For the first time, it becomes clear that adding gramicidin produces significant long-range and global effects on the structure of membrane domains: it alters the overall lipid compositions and bilayer thicknesses of coexisting Lo and Ld domains. We also found that gramicidin partitions favorably into the Ld phase. Adding gramicidin decreases cholesterol in the Ld phase and increases cholesterol in the Lo phase. Those compositional changes broaden the bilayer thickness difference between Lo and Ld domains and facilitate preferential partition of gramicidin into thinner Ld domains. Our results demonstrate that membrane proteins play significant roles in determining lipid compositions and bilayer thicknesses of biomembrane domains.

  19. Advanced Supported Liquid Membranes for Carbon Dioxide Control in Cabin Applications

    NASA Technical Reports Server (NTRS)

    Wickham, David T.; Gleason, Kevin J.; Engel, Jeffrey R.; Chullen, Cinda

    2016-01-01

    The development of new, robust, life support systems is critical to NASA's continued progress in space exploration. One vital function is maintaining the carbon dioxide (CO2) concentration in the cabin at levels that do not impair the health or performance of the crew. The CO2 removal assembly (CDRA) is the current CO2 control technology on-board the International Space Station (ISS). Although the CDRA has met the needs of the ISS to date, the repeated cycling of the molecular sieve sorbent causes it to break down into small particles that clog filters or generate dust in the cabin. This reduces reliability and increases maintenance requirements. Another approach that has potential advantages over the current system is a membrane that separates CO2 from air. In this approach, cabin air contacts one side of the membrane while other side of the membrane is maintained at low pressure to create a driving force for CO2 transport across the membrane. In this application, the primary power requirement is for the pump that creates the low pressure and then pumps the CO2 to the oxygen recovery system. For such a membrane to be practical, it must have high CO2 permeation rate and excellent selectivity for CO2 over air. Unfortunately, conventional gas separation membranes do not have adequate CO2 permeability and selectivity to meet the needs of this application. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a microporous material filled with a liquid that selectively reacts with CO2 over air. In a recently completed Phase II SBIR project, Reaction Systems, Inc. fabricated an SLM that is very close to meeting permeability and selectivity objectives for use in the advanced space suit portable life support system. This paper describes work carried out to evaluate its potential for use in spacecraft cabin application.

  20. Mass transfer of terpenes through a silicone rubber membrane in a liquid-liquid contacting system.

    PubMed

    Boontawan, Apichat; Stuckey, David C

    2005-01-01

    Terpenoids are important compounds for the fragrance industry, and recently, biocatalytic methods have been developed to produce them from cheap monoterpenes, such as alpha-pinene oxide. The biotransformation of alpha-pinene oxide using resting cells of Pseudomonas fluorescens NCIMB 11671 produces isonovalal (cis-2-methyl-5-isopropylhexa-2,5-dienal), which is a fragrance. However, this biotransformation has technical problems including the following: alpha-pinene oxide undergoes autoxidation in water and light; it is hydrophobic and relatively toxic to the biocatalyst; and it suffers from product inhibition. Therefore, removal of isonovalal as it is formed should reduce its toxicity and increase volumetric productivity and production yield. Aqueous-organic two-phase (AOTP) systems can be used in the biotransformation of hydrophobic substrates and can protect biocatalysts from toxic substrates and products. However, the formation of stable emulsions makes further downstream processing and continuous operation difficult. One solution to these problems is to use a solid-phase membrane between the aqueous and organic phases in a Membrane Bioreactor for Biotransformation (MBB). Since there are no data in the literature on the behavior of terpenes and terpenoids with solid-phase membranes, or their mass transfer behavior, the objective of this work was to measure these parameters for a wide range of compounds so as to be able to design an MBB, and to gain a greater understanding of their behavior in these types of systems. Organic/aqueous (P (org) (aq)) and membrane/aqueous (P (mem) (aq)) partition coefficients were measured first, and subsequently used to quantify the overall mass transfer coefficients (k(ov)). The overall mass transfer coefficient (k(ov)) of alpha-pinene oxide through the membrane was found to be 2.5 x 10(-5) m x s(-1) using thicknesses of both 250 and 1,000 microm. Extraction kinetics were successfully described using a resistance-in-series model and

  1. Enhanced ionic liquid mobility induced by confinement in 1D CNT membranes

    NASA Astrophysics Data System (ADS)

    Berrod, Q.; Ferdeghini, F.; Judeinstein, P.; Genevaz, N.; Ramos, R.; Fournier, A.; Dijon, J.; Ollivier, J.; Rols, S.; Yu, D.; Mole, R. A.; Zanotti, J.-M.

    2016-04-01

    Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators.Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) confined in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared to its bulk reference. This could lead to high power battery separators. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01445c

  2. Microemulsion liquid membranes. I. Application to acetic acid removal from water

    SciTech Connect

    Wiencek, J.M.; Qutubuddin, S. )

    1992-08-01

    A separation technique utilizing nonionic microemulsions as emulsion liquid membranes has been successfully applied to the removal of acetic acid from an aqueous feed phase. The surfactant systems were carefully characterized in order to assure that they were truly microemulsions. The effects of mixing intensity, feed concentration, treat ratio, and microemulsion viscosity on the separation kinetics were investigated. The microemulsions did not typically display leakage and had negligible swell over 5-minute duration. The reversible phase behavior of the microemulsion was utilized to demulsify the liquid membrane phase and recover the acetate ion via a temperature change of approximately 40 C. Material balances closed to within 10% and rates of separation were faster than the sampling rates when the microemulsion was fully dispersed in the aqueous feed phase.

  3. Membrane-based recovery of glucose from enzymatic hydrolysis of ionic liquid pretreated cellulose.

    PubMed

    Abels, Christian; Thimm, Kristof; Wulfhorst, Helene; Spiess, Antje Christine; Wessling, Matthias

    2013-12-01

    In this work, a membrane-based downstream process for the recovery of glucose from cellulose hydrolysis is described and evaluated. The cellulose is pretreated with the ionic liquid 1,3-dimethyl-imidazolium dimethylphosphate to reduce its crystallinity. After enzymatic conversion of cellulose to glucose the hydrolysate is filtered with an ultrafiltration membrane to remove residual particulates and enzymes. Nanofiltration is applied to purify the glucose from molecular intermediates, such as cellobiose originating from the hydrolysis reaction. Finally, the ionic liquid is removed from the hydrolysate via electrodialysis. Technically, these process steps are feasible. An economic analysis of the process reveals that the selling price of glucose from this production process is about 2.75 €/kg which is too high as compared to the current market price.

  4. Theoretical analysis of copper-ion extraction through hollow fiber supported liquid membranes

    SciTech Connect

    Shiau, C.Y.; Chen, P.Z. )

    1993-10-01

    An understanding of the extraction of metal ions through hollow fiber supported liquid membranes is important for the design of such systems. In this paper, copper-ion extraction through hollow fiber supported liquid membranes containing D2EHPA as a carrier agent is analyzed. Both a rigorous model and a simple model with varied permeation coefficients for the system are proposed. The once-through mode is first modeled and the parametric effects on the extraction rate are discussed. The recycling mode is then modeled. A comparison between the rigorous model and the simple model with varied/constant permeation coefficients is made. From the models it is found that the permeation coefficient is a function of copper ion concentration. 18 refs., 9 figs., 1 tab.

  5. Film and membrane-model thermodynamics of free thin liquid films.

    PubMed

    Radke, C J

    2015-07-01

    In spite of over 7 decades of effort, the thermodynamics of thin free liquid films (as in emulsions and foams) lacks clarity. Following a brief review of the meaning and measurement of thin-film forces (i.e., conjoining/disjoining pressures), we offer a consistent analysis of thin-film thermodynamics. By carefully defining film reversible work, two distinct thermodynamic formalisms emerge: a film model with two zero-volume membranes each of film tension γ(f) and a membrane model with a single zero-volume membrane of membrane tension 2γ(m). In both models, detailed thermodynamic analysis gives rise to thin-film Gibbs adsorption equations that allow calculation of film and membrane tensions from measurements of disjoining-pressure isotherms. A modified Young-Laplace equation arises in the film model to calculate film-thickness profiles from the film center to the surrounding bulk meniscus. No corresponding relation exists in the membrane model. Illustrative calculations of disjoining-pressure isotherms for water are presented using square-gradient theory. We report considerable deviations from Hamaker theory for films less than about 3 nm in thickness. Such thin films are considerably more attractive than in classical Hamaker theory. Available molecular simulations reinforce this finding.

  6. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    SciTech Connect

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  7. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 11, March 21, 1992--June 20, 1992

    SciTech Connect

    Tsotsis, T.T.

    1992-12-31

    Membrane reactors have been used in a number of catalytic reaction processes in order to overcome the limitations on conversion imposed by thermodynamic equilibrium. Having the inherent capability for combining reaction and separation in a single step, they offer promise for improving and optimizing yield, selectivity and performance of processes involving complex liquids, such as these typically found in coal liquid upgrading. Ceramic membranes are a new class of materials, which have shown promise in a variety of industrial applications. Their mechanical and chemical stability coupled with a wide range of operating temperatures and pressures make them suitable for environments found in coal liquid upgrading. This project will evaluate the performance of Sol-Gel alumina membranes in coal liquid upgrading processes under realistic temperature and pressure conditions and investigate the feasibility of using such membranes in a membrane reactor based coal liquid upgrading process. Development of novel ceramic membranes with enhanced catalytic activity for coal-liquid upgrading applications, such as carbon-coated alumina membranes, will be also investigated.

  8. Performance evaluation of microbial electrochemical systems operated with Nafion and supported ionic liquid membranes.

    PubMed

    Koók, László; Nemestóthy, Nándor; Bakonyi, Péter; Zhen, Guangyin; Kumar, Gopalakrishnan; Lu, Xueqin; Su, Lianghu; Saratale, Ganesh Dattatraya; Kim, Sang-Hyoun; Gubicza, László

    2017-05-01

    In this work, the performance of dual-chamber microbial fuel cells (MFCs) constructed either with commonly used Nafion(®) proton exchange membrane or supported ionic liquid membranes (SILMs) was assessed. The behavior of MFCs was followed and analyzed by taking the polarization curves and besides, their efficiency was characterized by measuring the electricity generation using various substrates such as acetate and glucose. By using the SILMs containing either [C6mim][PF6] or [Bmim][NTf2] ionic liquids, the energy production of these MFCs from glucose was comparable to that obtained with the MFC employing polymeric Nafion(®) and the same substrate. Furthermore, the MFC operated with [Bmim][NTf2]-based SILM demonstrated higher energy yield in case of low acetate loading (80.1 J g(-1) CODin m(-2) h(-1)) than the one with the polymeric Nafion(®) N115 (59 J g(-1) CODin m(-2) h(-1)). Significant difference was observed between the two SILM-MFCs, however, the characteristics of the system was similar based on the cell polarization measurements. The results suggest that membrane-engineering applying ionic liquids can be an interesting subject field for bioelectrochemical system research.

  9. Facilitated transport of carbon dioxide through supported liquid membranes of aqueous amine solutions

    SciTech Connect

    Teramoto, Masaaki; Nakai, Katsuya; Ohnishi, Nobuaki; Huang, Q.; Watari, Takashi; Matsuyama, Hideto

    1996-02-01

    A series of experiments on the facilitated transport of CO{sub 2} through supported liquid membranes containing monoethanolamine (MEA) and diethanolamine (DEA) was performed. The feed gas was a mixture of CO{sub 2} and CH{sub 4}, and the CO{sub 2} partial pressure p{sub CO{sub 2},F} was in the range from 0.05 to 0.97 atm. Compared to the MEA membranes, the DEA membranes showed a little higher permeation rate of CO{sub 2} since the equilibrium constant of the reaction between CO{sub 2} and MEA is too large for CO{sub 2} to be released to the receiving phase rapidly. When p{sub CO{sub 2},F} and the MEA concentration were 0.05 atm and 4 mol/dm{sup 3}, respectively, the separation factor {alpha}(CO{sub 2}/CH{sub 4}) was about 2,000. It was found that if the membrane thickness multiplied by the square root of the tortuosity factor of the microporous support membrane is used as the effective pore length, the experimentally observed permeation rates of CO{sub 2} can be satisfactorily simulated by the theory of facilitated transport of CO{sub 2} through aqueous amine membranes. A method for estimating the solubilities of CO{sub 2} in the membrane solutions from the permeation rates of CH{sub 4} was also proposed. It was also found that permeation rates of CO{sub 2} through aqueous DEA membranes reported by Guha et al. were quantitatively explained by the proposed theory.

  10. Development of a Supported Emulsion Liquid Membrane System for Propionic Acid Separation in a Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Li, Jin; Hu, Shih-Yao B.; Wiencek, John M.

    2001-01-01

    Perstractive fermentation is a good way to increase the productivity of bioreactors. Using Propionibacteria as the model system, the feasibility of using supported emulsion liquid membrane (SELM) for perstractive fermentation is assessed in this study. Five industrial solvents were considered as the solvent for preparing the SELM. The more polar a solvent is, the higher the partition coefficient. However, toxicity of a solvent also increases with its polarity. CO-1055 (industrial decanol/octanol blend) has the highest partition coefficient toward propionic acid among the solvents that has no molecular toxicity toward Propionibacteria. A preliminary extraction study was conducted using tetradecane as solvent in a hydrophobic hollow fiber contactor. The result confirmed that SELM eliminates the equilibrium limitation of conventional liquid-liquid extraction, and allows the use of a non-toxic solvent with low partition coefficient.

  11. Determination of phthalate ester plasticizers in the aquatic environment using hollow fibre supported liquid membranes

    NASA Astrophysics Data System (ADS)

    Mtibe, A.; Msagati, Titus A. M.; Mishra, Ajay K.; Mamba, Bhekie B.

    Phthalates are known to be carcinogenic, teratogenic as well as endocrine disruptors. The potential risk to human and animals health generated from them has drawn great attention all over the world. Hollow fibre supported liquid membrane (HFSLM) online with high pressure liquid chromatography (HPLC) was used to determine benzyl butyl phthalate (BBP), dibutyl phthalate (DBP) and Diethylhexyl phthalate (DEHP) in wastewater. Toluene, di-n-hexyl ether and undecane were used as liquid barriers separating both donor (sample) and acceptor phase. Toluene performed much better than undecane and was used in sample preparation. The presence of toluene showed the potential for the enrichment and removal of phthalates to the concentrations ranges from 0 to 1.7 mg L-1.

  12. Mechanical and optical behavior of a tunable liquid lens using a variable cross section membrane: modeling results

    NASA Astrophysics Data System (ADS)

    Flores-Bustamante, Mario C.; Rosete-Aguilar, Martha; Calixto, Sergio

    2016-03-01

    A lens containing a liquid medium and having at least one elastic membrane as one of its components is known as an elastic membrane lens (EML). The elastic membrane may have a constant or variable thickness. The optical properties of the EML change by modifying the profile of its elastic membrane(s). The EML formed of elastic constant thickness membrane(s) have been studied extensively. However, EML information using elastic membrane of variable thickness is limited. In this work, we present simulation results of the mechanical and optical behavior of two EML with variable thickness membranes (convex-plane membranes). The profile of its surfaces were modified by liquid medium volume increases. The model of the convex-plane membranes, as well as the simulation of its mechanical behavior, were performed using Solidworks® software; and surface's points of the deformed elastic lens were obtained. Experimental stress-strain data, obtained from a silicone rubber simple tensile test, according to ASTM D638 norm, were used in the simulation. Algebraic expressions, (Schwarzschild formula, up to four deformation coefficients, in a cylindrical coordinate system (r, z)), of the meridional profiles of the first and second surfaces of the deformed convex-plane membranes, were obtained using the results from Solidworks® and a program in the software Mathematica®. The optical performance of the EML was obtained by simulation using the software OSLO® and the algebraic expressions obtained in Mathematica®.

  13. Phase transfer membrane supported liquid-liquid-liquid microextraction combined with large volume sample injection capillary electrophoresis-ultraviolet detection for the speciation of inorganic and organic mercury.

    PubMed

    Li, Pingjing; Zhang, Xing; Hu, Bin

    2011-12-30

    In this paper, a novel sample pretreatment technique termed phase transfer based liquid-liquid-liquid microextraction (PT-LLLME) was proposed for the simultaneous extraction of inorganic and organic mercury species. In PT-LLLME, an intermediate solvent (acetonitrile) was added into the donor phase to improve the contacting between target mercury species and complexing reagent. Meanwhile, a membrane supported (MS)-LLLME unit was designed to realize the PT-LLLME procedure. By using nylon membrane as supporting carrier, larger than 50 μL of acceptor solution could be hung up. Following PT/MS-LLLME, the acceptor solutions were directly analyzed by large volume sample stacking capillary electrophoresis/ultraviolet detection (LVSS-CE/UV). Accordingly, a new method of PT/MS-LLLME combined with LVSS-CE/UV was developed for the simultaneous speciation of inorganic and organic mercury species. Parameters affecting the extraction efficiency of PT/MS-LLLME were investigated in details. Under the optimized conditions, enrichment factors (EFs) ranging from 160- to 478-fold were obtained for the extraction of target mercury species by PT/MS-LLLME. By combining PT/MS-LLLME with LVSS-CE/UV, EFs were magnified up to 12,138-fold and the limits of detection (at a signal-to-noise ratio of 3) were at sub ppb level. The established approach of PT/MS-LLLME-LVSS-CE/UV was successfully applied to simultaneous determination of inorganic and organic mercury species in biological samples and environmental water samples.

  14. Development of Bitter Taste Sensor Using Ionic-Liquid/Polymer Membranes

    NASA Astrophysics Data System (ADS)

    Akutagawa, Nobuyuki; Toida, Jinichi; Amano, Yoshihiko; Ikezaki, Hidekazu; Toko, Kiyoshi; Arikawa, Yukihiko

    A taste sensor is composed of several kinds of lipid/polymer membranes as transducers which convert taste information to electric signal. Thus, the role of membranes is very important to detect various taste components. In this paper, we developed novel membranes which specifically respond to quinine that is typical bitter substances. These membranes were composed of hydrophobic ionic liquid such as N, N, N-trimethyl-N-propylammonium bis(trifluoromethansulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butylpyridinium hexafluorophosphate, a plasticizer, 2-nitrophenyl octyl ether and a polymer, polyvinyl chloride. In addition to quinine, they also showed response to both several kinds of alkaloids such as caffeine and strychnine, and non-alkaloid such as phenylthiocarbamide. The order of these responses was equal to that of the tongue glossopharyngeal nerve of flog. Furthermore, there were the other alkaloids which response to these membranes. Especially in these alkaloids, they showed high response to denatonium benzoate and berberin chloride which have a strong bitter taste.

  15. Engineering lipid structure for recognition of the liquid ordered membrane phase

    DOE PAGES

    Bordovsky, Stefan S.; Wong, Christopher S.; Bachand, George D.; ...

    2016-08-26

    The selective partitioning of lipid components in phase-separated membranes is essential for domain formation involved in cellular processes. Identifying and tracking the movement of lipids in cellular systems would be improved if we understood how to achieve selective affinity between fluorophore-labeled lipids and membrane assemblies. Furthermore, we investigated the structure and chemistry of membrane lipids to evaluate lipid designs that partition to the liquid ordered (Lo) phase. A range of fluorophores at the headgroup position and lengths of PEG spacer between the lipid backbone and fluorophore were examined. On a lipid body with saturated palmityl or palmitoyl tails, we foundmore » that although the lipid tails can direct selective partitioning to the Lo phase through favorable packing interactions, headgroup hydrophobicity can override the partitioning behavior and direct the lipid to the disordered membrane phase (Ld). The PEG spacer can serve as a buffer to mute headgroup–membrane interactions and thus improve Lo phase partitioning, but its effect is limited with strongly hydrophobic fluorophore headgroups. We present a series of lipid designs leading to the development of novel fluorescently labeled lipids with selective affinity for the Lo phase.« less

  16. Engineering lipid structure for recognition of the liquid ordered membrane phase

    SciTech Connect

    Bordovsky, Stefan S.; Wong, Christopher S.; Bachand, George D.; Stachowiak, Jeanne C.; Sasaki, Darryl Y.

    2016-08-26

    The selective partitioning of lipid components in phase-separated membranes is essential for domain formation involved in cellular processes. Identifying and tracking the movement of lipids in cellular systems would be improved if we understood how to achieve selective affinity between fluorophore-labeled lipids and membrane assemblies. Furthermore, we investigated the structure and chemistry of membrane lipids to evaluate lipid designs that partition to the liquid ordered (Lo) phase. A range of fluorophores at the headgroup position and lengths of PEG spacer between the lipid backbone and fluorophore were examined. On a lipid body with saturated palmityl or palmitoyl tails, we found that although the lipid tails can direct selective partitioning to the Lo phase through favorable packing interactions, headgroup hydrophobicity can override the partitioning behavior and direct the lipid to the disordered membrane phase (Ld). The PEG spacer can serve as a buffer to mute headgroup–membrane interactions and thus improve Lo phase partitioning, but its effect is limited with strongly hydrophobic fluorophore headgroups. We present a series of lipid designs leading to the development of novel fluorescently labeled lipids with selective affinity for the Lo phase.

  17. Pervaporation performance of PPO membranes in dehydration of highly hazardous mmh and udmh liquid propellants.

    PubMed

    Moulik, Siddhartha; Kumar, K Praveen; Bohra, Subha; Sridhar, Sundergopal

    2015-05-15

    Polyphenylene oxide (PPO) membranes synthesized from 2,6-dimethyl phenol monomer were subjected to pervaporation-based dehydration of the highly hazardous and hypergolic monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) liquid propellants. Membranes were characterized by TGA, DSC and SEM to study the effect of temperature besides morphologies of surface and cross-section of the films, respectively. Molecular dynamics (MD) simulation was used to study the diffusion behavior of solutions within the membrane. CFD method was employed to solve the governing mass transfer equations by considering the flux coupling. The modeling results were highlighted by the experimental data and were in good agreement. High separation factors (35-70) and reasonable water fluxes (0.1-0.2 kg/m(2)h) were observed for separation of the aqueous azeotropes of MMH (35 wt%) and UDMH (20 wt%) and their further enrichment to >90% purity. Effect of feed composition, membrane thickness and permeate pressure on separation performance of PPO membranes were investigated to determine optimum operating conditions.

  18. Can sonication enhance release from liquid-core capsules with a hydrogel membrane?

    PubMed

    Zhang, Liguo; Salsac, Anne-Virginie

    2012-02-15

    The objective is to investigate the influence of sonication on the mechanical and release properties of hydrogel capsules. A new fabrication process is developed to fabricate millimetric capsules made of a highly-viscous liquid core protected by a thin hyperelastic alginate membrane. At high intensities and/or long exposure times, sonication can lead to the capsule rupture, because it induces fatigue in the membrane. Below the breakup threshold, no remnant effect of sonication is, however, measured on the capsule mechanical properties. The release is studied by sonicating capsules filled with blue dextran suspended in an aqueous solution. The mass release that results from sonication is found to be proportional to the sonication duration time and pressure wave amplitude. A possible physical interpretation is that the acoustic streaming flow induced by the ultrasonic wave enhances convection in the vicinity of the capsule membrane and thus mass release. We have finally quantified the passive release subsequent to low-intensity sonications: it is on average identical to the one measured on non-sonicated capsules. Overall the membrane therefore recovers its physical and mechanical properties after sonication. If sonication leads to an increase in porosity of the capsule membrane, the increase is temporary and reverses back at the end of the ultrasonic stimulation.

  19. Global Analysis of the Membrane Subproteome of Pseudomonas aeruginosa using Liquid Chromatography-Tandem Mass Spectrometry

    SciTech Connect

    Blonder, Josip; Goshe, Michael B.; Xiao, Wenzhong; Camp, David G.; Wingerd, Mark A.; Davis, Ronald W.; Smith, Richard D.

    2004-05-30

    Pseudomonas aeruginosa is one of the most significant opportunistic bacterial pathogens in humans causing infections and premature death in patients with cystic fibrosis, AIDS, severe burns, organ transplants or cancer. Liquid chromatography coupled online with tandem mass spectrometry (LC-MS/MS) was used for the large-scale proteomic analysis of the P. aeruginosa membrane subproteome. Concomitantly, an affinity labeling technique, using iodoacetyl-PEO biotin to tag cysteinyl-containing proteins, permitted the enrichment and detection of lower abundance membrane proteins. The application of these approaches resulted in the identification of 786 proteins. A total of 333 proteins (42%) had a minimum of one transmembrane domain (TMD; ranging from 1 to 14) and 195 proteins were classified as hydrophobic based on their positive GRAVY values (ranging from 0.01 to 1.32). Key integral inner and outer membrane proteins involved in adaptation and antibiotic resistance were conclusively identified, including the detection of 53% of all predicted opr-type porins (outer integral membrane proteins) and all the components of the mexA-mexB-oprM transmembrane protein complex. This work represents the most comprehensive qualitative proteomic analysis of the membrane subproteome of P. aeruginosa and for prokaryotes in general to date.

  20. Advanced Supported Liquid Membranes for CO2 Control in Extravehicular Activity Applications

    NASA Technical Reports Server (NTRS)

    Wickham, David T.; Gleason, Kevin J.; Engel, Jeffrey R.; Cowley, Scott W.; Chullen, Cinda

    2014-01-01

    Developing a new, robust, portable life support system (PLSS) is currently a high priority for NASA in order to support longer and safer extravehicular activity (EVA) missions. One of the critical PLSS functions is maintaining the carbon dioxide (CO2) concentration in the suit at acceptable levels. Although the Metal Oxide (MetOx) canister has worked well, it has a finite CO2 adsorption capacity. Consequently, the unit would have to be larger and heavier to extend EVA times. Therefore, new CO2 control technologies must be developed to meet mission objectives without increasing the size of the PLSS. Although recent work has centered on sorbents that can be regenerated during the EVA, this strategy increases the system complexity and power consumption. A simpler approach is to use a membrane that selectively vents CO2 to space. A membrane has many advantages over current technology: it is a continuous system with no theoretical capacity limit, it requires no consumables, and it requires no hardware for switching beds between absorption and regeneration. Unfortunately, conventional gas separation membranes do not have adequate selectivity for use in the PLSS. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a micro porous material filled with a liquid that selectively reacts with CO2 over oxygen (O2). In a current Phase II SBIR project, Reaction Systems has developed a new reactive liquid, which has effectively zero vapor pressure making it an ideal candidate for use in an SLM. The SLM function has been demonstrated with representative pressures of CO2, O2, and water (H2O). In addition to being effective for CO2 control, the SLM also vents moisture to space. Therefore, this project has demonstrated the feasibility of using an SLM to control CO2 in an EVA application. 1 President

  1. Advanced Supported Liquid Membranes for CO2 Control in Extravehicular Activity Applications

    NASA Technical Reports Server (NTRS)

    Wickham, David T.; Gleason, Kevin J.; Engel, Jeffrey R.; Cowley, Scott W.; Chullen, Cinda

    2014-01-01

    Developing a new, robust, portable life support system (PLSS) is currently a high priority for NASA in order to support longer and safer extravehicular activity (EVA) missions. One of the critical PLSS functions is maintaining the carbon dioxide (CO2) concentration in the suit at acceptable levels. Although the Metal Oxide (MetOx) canister has worked well, it has a finite CO2 adsorption capacity. Consequently, the unit would have to be larger and heavier to extend EVA times. Therefore, new CO2 control technologies must be developed to meet mission objectives without increasing the size of the PLSS. Although recent work has centered on sorbents that can be regenerated during the EVA, this strategy increases the system complexity and power consumption. A simpler approach is to use a membrane that selectively vents CO2 to space. A membrane has many advantages over current technology: it is a continuous system with no theoretical capacity limit, it requires no consumables, and it requires no hardware for switching beds between absorption and regeneration. Unfortunately, conventional gas separation membranes do not have adequate selectivity for use in the PLSS. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a micro porous material filled with a liquid that selectively reacts with CO2 over oxygen (O2). In a current Phase II SBIR project, Reaction Systems has developed a new reactive liquid, which has effectively zero vapor pressure making it an ideal candidate for use in an SLM. The SLM function has been demonstrated with representative pressures of CO2, O2, and water (H2O). In addition to being effective for CO2 control, the SLM also vents moisture to space. Therefore, this project has demonstrated the feasibility of using an SLM to control CO2 in an EVA application.

  2. Size Control and Fractionation of Ionic Liquid Filled Polymersomes with Glassy and Rubbery Bilayer Membranes.

    PubMed

    So, Soonyong; Lodge, Timothy P

    2016-05-17

    We demonstrate control over the size of ionic liquid (IL) filled polymeric vesicles (polymersomes) by three distinct methods: mechanical extrusion, cosolvent-based processing in an IL, and fractionation of polymersomes in a biphasic system of IL and water. For the representative ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][TFSI])), the size and dispersity of polymersomes formed from 1,2-polybutadiene-b-poly(ethylene oxide) (PB-PEO) and polystyrene-b-poly(ethylene oxide) (PS-PEO) diblock copolymers were shown to be sensitive to assembly conditions. During mechanical extrusion through a polycarbonate membrane, the relatively larger polymersomes were broken up and reorganized into vesicles with mean size comparable to the membrane pore (100 nm radius); the distribution width also decreased significantly after only a few passes. Other routes were studied using the solvent-switch or cosolvent (CS) method, whereby the initial content of the cosolvent and the PEO block length of PS-PEO were systemically changed. The nonvolatility of the ionic liquid directly led to the desired concentration of polymersomes in the ionic liquid using a single step, without the dialysis conventionally used in aqueous systems, and the mean vesicle size depended on the amount of cosolvent employed. Finally, selective phase transfer of PS-PEO polymersomes based on size was used to extract larger polymersomes from the IL to the aqueous phase via interfacial tension controlled phase transfer. The interfacial tension between the PS membrane and the aqueous phase was varied with the concentration of sodium chloride (NaCl) in the aqueous phase; then the larger polymersomes were selectively separated to the aqueous phase due to differences in shielding of the hydrophobic core (PS) coverage by the hydrophilic corona brush (PEO). This novel fractionation is a simple separation process without any special apparatus and can help to prepare monodisperse polymersomes

  3. Poly(ionic liquid)/Ionic Liquid Ion-Gels with High "Free" Ionic Liquid Content: Platform Membrane Materials for CO2/Light Gas Separations.

    PubMed

    Cowan, Matthew G; Gin, Douglas L; Noble, Richard D

    2016-04-19

    -films (ca. 100-nm-thick active layer). Traditional polymeric membrane materials are limited by a trade-off between permeability and selectivity empirically described by the "Robeson upper bound"-placing the desired membrane properties beyond reach. Therefore, the investigation of advanced and composite materials that can overcome the limitations of traditional polymeric materials is the focus of significant academic and industrial research. In particular, there has been substantial work on ionic-liquid (IL)-based materials due to their gas transport properties. This review provides an overview of our collaborative work on developing poly(ionic liquid)/ionic liquid (PIL/IL) ion-gel membrane technology. We detail developmental work on the preparation of PIL/IL composites and describe how this chemical technology was adapted to allow the roll-to-roll processing and preparation of membranes with defect-free active layers ca. 100 nm thick, CO2 permeances of over 6000 GPU, and CO2/N2 selectivity of ≥20-properties with the potential to reduce the cost of CO2 removal from coal-fired power plant flue gas to ca. $15 per ton of CO2 captured. Additionally, we examine the materials developments that have produced advanced PIL/IL composite membranes. These advancements include cross-linked PIL/IL blends, step-growth PIL/IL networks with facilitated transport groups, and PIL/IL composites with microporous additives for CO2/CH4 separations.

  4. Hollow-fiber-supported liquid membrane microextraction of amlodipine and atorvastatin.

    PubMed

    Panahi, Homayon Ahmad; Chabouk, Monireh; Ejlali, Maryam

    2014-08-01

    A simple, environmentally friendly, and efficient method, based on hollow-fiber-supported liquid membrane microextraction, followed by high-performance liquid chromatography has been developed for the extraction and determination of amlodipine (AML) and atorvastatin (ATO) in water and urine samples. The AML in two-phase hollow-fiber liquid microextraction is extracted from 24.0 mL of the aqueous sample into an organic phase with microliter volume located inside the pores and lumen of a polypropylene hollow fiber as acceptor phase, but the ATO in three-phase hollow-fiber liquid microextraction is extracted from aqueous donor phase to organic phase and then back-extracted to the aqueous acceptor phase, which can be directly injected into the high-performance liquid chromatograph for analysis. The preconcentration factors in a range of 34-135 were obtained under the optimum conditions. The calibration curves were linear (R(2) ≥ 0.990) in the concentration range of 2.0-200 μg/L for AML and 5.0-200 μg/L for ATO. The limits of detection for AML and ATO were 0.5 and 2.0 μg/L, respectively. Tap water and human urine samples were successfully analyzed for the existence of AML and ATO using the proposed methods.

  5. Partial delignification of wood and membrane preparation using a quaternary ammonium ionic liquid

    PubMed Central

    Miao, Jiaojiao; Yu, Yongqi; Jiang, Zeming; Tang, Lan; Zhang, Liping

    2017-01-01

    This work determined that southern yellow pine wood can almost be completely dissolved in the quaternary ammonium ionic liquid tetrabutylammonium acetate with dimethyl sulfoxide (in a 2:8 mass ratio), after minimal grinding, upon heating at 85 °C for three dissolution/reconstitution cycles, each 1.5 h. Approximately 34.6% of the native lignin and 67.4% of the native carbohydrates present in the original wood can subsequently be extracted, respectively, and were assessed. A gradual decrease in lignin with increased extraction cycles resulted in increased crystallinity index of the cellulose II in the cellulose-rich residue, as confirmed by X-ray diffraction. An increasingly homogeneous macrostructure in the cellulose-rich residue was also evident from scanning electron microscopy images. Membranes cast directly from either wood or cellulose-rich residue solutions in the same tetrabutylammonium acetate/dimethyl sulfoxide system, were prepared using a papermaking-like process. Morphological and mechanical studies indicated that lignin extraction made the membranes more uniform and flexible. Systematic increases in the fibril lengths and orientations of the recovered materials were also found with decreasing lignin contents on the basis of atomic force microscopy analysis. This work demonstrates that relatively efficient partial separation of pine wood and subsequent membrane preparation are possible using a quaternary ammonium ionic liquid. PMID:28266507

  6. The binary eutectic of NSAIDS and two-phase liquid system for enhanced membrane permeation.

    PubMed

    Yuan, Xudong; Capomacchia, A C

    2005-01-01

    The eutectic properties of binary mixtures of some nonsteroidal anti-inflammatory drugs (NSAIDs) with ibuprofen were studied using differential scanning calorimetry (DSC) and phase equilibrium diagrams. The melting points of selected NSAIDs were significantly depressed due to binary eutectic formation with ibuprofen. Ketoprofen and ibuprofen were selected to study the effect of eutectic formation on membrane permeation using Franz diffusion cells and snake skin as the model membrane. The presence of aqueous isopropyl alcohol (IPA) was necessary to completely transform the solid drugs into an oily state at ambient temperature. As much as the 99.6% of ibuprofen and the 88.8% of ketoprofen added were found in the oily phase of the two-phase liquid system formed when aqueous IPA was added to the eutectic mixture. Due to the high drug concentration in the oily phase, and maximum thermodynamic activity, the two-phase liquid system showed enhanced membrane permeation rates of ibuprofen (37.5 microg/cm2/hr) and ketoprofen (33.4 microg/cm2/hr) compared to other reference preparations used.

  7. Partial delignification of wood and membrane preparation using a quaternary ammonium ionic liquid

    NASA Astrophysics Data System (ADS)

    Miao, Jiaojiao; Yu, Yongqi; Jiang, Zeming; Tang, Lan; Zhang, Liping

    2017-03-01

    This work determined that southern yellow pine wood can almost be completely dissolved in the quaternary ammonium ionic liquid tetrabutylammonium acetate with dimethyl sulfoxide (in a 2:8 mass ratio), after minimal grinding, upon heating at 85 °C for three dissolution/reconstitution cycles, each 1.5 h. Approximately 34.6% of the native lignin and 67.4% of the native carbohydrates present in the original wood can subsequently be extracted, respectively, and were assessed. A gradual decrease in lignin with increased extraction cycles resulted in increased crystallinity index of the cellulose II in the cellulose-rich residue, as confirmed by X-ray diffraction. An increasingly homogeneous macrostructure in the cellulose-rich residue was also evident from scanning electron microscopy images. Membranes cast directly from either wood or cellulose-rich residue solutions in the same tetrabutylammonium acetate/dimethyl sulfoxide system, were prepared using a papermaking-like process. Morphological and mechanical studies indicated that lignin extraction made the membranes more uniform and flexible. Systematic increases in the fibril lengths and orientations of the recovered materials were also found with decreasing lignin contents on the basis of atomic force microscopy analysis. This work demonstrates that relatively efficient partial separation of pine wood and subsequent membrane preparation are possible using a quaternary ammonium ionic liquid.

  8. A simple supported liquid hollow fiber membrane microextraction for sample preparation of trihalomethanes in water samples.

    PubMed

    Vora-adisak, Narongchai; Varanusupakul, Pakorn

    2006-07-21

    A simple and efficient liquid-phase microextraction (LPME) technique using a supported liquid hollow fiber membrane, in conjunction with gas chromatography-electron capture detector has been developed for extraction and determination of trihalomethanes (THMs) in water samples. THMs were extracted from water samples through an organic extracting solvent impregnated in the pores and filled inside the porous hollow fiber membrane. Our simple conditions were conducted at 35 degrees C with no stirring and no salt addition in order to minimize sample preparation steps. Parameters such as types of hollow fiber membranes, extracting solvents and extraction time were studied and optimized. The method exhibited enrichment factors ranged from 28- to 62-fold within 30 min extraction time. The linearity of the method ranged from 0.2 to 100 microg l(-1). The limits of detection were in the low microg l(-1) level, ranging between 0.01 and 0.2 microg l(-1). The recoveries of spiked THMs at 5 microg l(-1) in water were between 98 and 105% with relative standard deviations (RSDs) less than 4%. Furthermore, the method was applied for determination of THMs in drinking water and tap water samples was reported.

  9. 4-nitrophenol removal from aqueous solutions by emulsion liquid membranes using type I facilitation.

    PubMed

    León, G; Guzmán, M A; Miguel, B

    2013-01-01

    Nitrophenols are common organic pollutants that enter the environment during the manufacture and processing of a variety of industrial products. The removal of 4-nitrophenol (4NP) from aqueous solutions by emulsion liquid membranes using the type I facilitated transport mechanism is investigated in this paper. The liquid membrane consisted of kerosene as the organic diluent, sorbitan monooleate as the emulsifying agent and sodium hydroxide as the stripping agent. The most important operational variables governing the emulsion stability and the 4NP removal process--such as the stripper agent and surfactant concentrations, the volume ratios of membrane phase/internal phase and emulsion phase/feed phase and stirring speed - were studied and the optimal conditions of the removal process were experimentally determined. Apparent initial permeabilities of the transport process in the different operational conditions were also obtained. Ninety-eight per cent of4NP was removed in 10 minutes and an apparent initial permeability of 1.2986 min(-1) was obtained in those optimal conditions.

  10. Separation of boric acid in liquid waste with anion exchange membrane contactor

    SciTech Connect

    Park, J.K.; Lee, K.J.

    1995-12-31

    In order to separate boric acid in liquid waste, some possible technologies were investigated and the membrane contactor without dispersion and density differences was selected. The separation experiments on a Celgard 3401{reg_sign} hydrophilic microporous membrane contactor were first performed to obtain the basic data and to determine the properties of the contactor. The experimental conditions were as follows: boric acid concentrations up to 2.0 M, pH 7.0, temperatures of 25 and 55 C, and flow rates of 100, 300, 500, and 800 cm{sup 3}/min. Secondly, an AFN{reg_sign} anion exchange membrane contactor was tested at temperatures of 40 and 55 C and flow rate 400 cm{sup 3}/min. Boric acid solutions were prepared by the same method as that for Celgard 3401{reg_sign} but contained 5.0{times}10{sup {minus}4} M cobalt chloride (CoCl{sub 2}). To simulate membrane contractors, parameters such as the differential diffusion coefficients of boric acid and the mass transfer coefficients in the AFN membrane were measured, and regression models estimating the diffusion coefficient at several conditions were developed. The Celgard 3401{reg_sign} membrane contactor was simulated and compared with experimental data. Simulation results agreed with the experimental data well when a proper correction factor was utilized. The correction factor was independent of the solution temperature and was 8.75 at the flow rates of 300--800 cm{sup 3}/min. This correction factor was also applied to simulate the AFN{reg_sign} resulted in a good agreement with experiment at 40 C, but not 55 C. The retention on cobalt was also better at 40 c than 55 C. The simulating computer program was also applied to a life size contactor designed conceptually.

  11. Reversed-phase liquid chromatographic retention and membrane activity relationships of local anesthetics.

    PubMed

    Tsuchiya, Hironori; Mizogami, Maki; Takakura, Ko

    2005-05-06

    The chromatographic retention and membrane activity relationships of local anesthetics were studied to address the possible mechanisms for structure specificity and inflammation-associated decrease of their effects. Five representative drugs (3 mM for each) were reacted with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine liposomes in 25 mM potassium phosphate buffer (pH 5.9-7.9, containing 100 mM NaCl and 0.1 mM EDTA) for 10 min at 37 degrees C and the membrane fluidity changes were analyzed by measuring fluorescence polarization with 1,6-diphenyl-1,3,5-hexatriene. Their capacity factors were determined on octadecyl-, octyl- and phenyl-bonded silica columns with a mobile phase consisting of 25 mM potassium phosphate buffer (pH 5.9-7.9, containing 100 mM NaCl and 0.1 mM EDTA)-methanol (30:70, v/v) at a flow rate of 1.0 ml/min and at a column temperature of 37 degrees C and diode-array detection. Mepivacaine, prilocaine, lidocaine, ropivacaine and bupivacaine fluidized membranes in increasing order of intensity, which agreed with their clinical potency. The relative degree of membrane fluidization correlated with that of retention on an octadecyl stationary phase more significantly than the other phases. Both membrane-fluidizing effects and capacity factors decreased by lowering the reaction and mobile phase pH, being consistent with the hypothesis that anesthetic potency is reduced in inflammation because of tissue acidity. Reversed-phase liquid chromatography appears to be useful for estimating the structure-specific and pH-dependent membrane-fluidizing effects of local anesthetics.

  12. Selective extraction of triazine herbicides from food samples based on a combination of a liquid membrane and molecularly imprinted polymers.

    PubMed

    Mhaka, Byron; Cukrowska, Ewa; Bui, Bernadette Tse Sum; Ramström, Olof; Haupt, Karsten; Tutu, Hlanganani; Chimuka, Luke

    2009-10-02

    A selective extraction technique based on the combination of liquid membrane (microporous membrane liquid-liquid extraction) and molecularly imprinted polymers (MIP) was applied to triazines herbicides in food samples. Simazine, atrazine and propazine were extracted from aqueous food samples through the hydrophobic porous membrane that was impregnated with toluene, which also formed part of the acceptor phase. In the acceptor phase, the compounds were re-extracted onto MIP particles. The extraction technique was optimised for the amount of molecularly imprinted polymers particles in the organic acceptor phase, extraction time, and type of organic acceptor solvent and desorption solvent. An extraction time of 90 min and 50mg of MIP were found to be optimum parameters. Toluene as the acceptor phase was found to give higher triazines binding onto MIP particles compared to hexane and combinations of diethyl ether and hexane. 90% methanol in water was found to be the best desorption solvent compared to acetonitrile, methanol and water. The selectivity of the technique was demonstrated by extracting spiked lettuce and apple extracts where clean chromatograms were obtained compared to liquid membrane extraction alone or to the microporous membrane liquid-liquid extraction - non-imprinted polymer combination. The MIP showed a certain degree of group specificity and the extraction efficiency in lettuce extract was 79% (0.72) for simazine, 98% (1.55) for atrazine and 86% (3.08) for propazine.

  13. Synthesis gas production by mixed conducting membranes with integrated conversion into liquid products

    DOEpatents

    Nataraj, Shankar; Russek, Steven Lee; Dyer, Paul Nigel

    2000-01-01

    Natural gas or other methane-containing feed gas is converted to a C.sub.5 -C.sub.19 hydrocarbon liquid in an integrated system comprising an oxygenative synthesis gas generator, a non-oxygenative synthesis gas generator, and a hydrocarbon synthesis process such as the Fischer-Tropsch process. The oxygenative synthesis gas generator is a mixed conducting membrane reactor system and the non-oxygenative synthesis gas generator is preferably a heat exchange reformer wherein heat is provided by hot synthesis gas product from the mixed conducting membrane reactor system. Offgas and water from the Fischer-Tropsch process can be recycled to the synthesis gas generation system individually or in combination.

  14. Removal of acetic acid from simulated hemicellulosic hydrolysates by emulsion liquid membrane with organophosphorus extractants.

    PubMed

    Lee, Sang Cheol

    2015-09-01

    Selective removal of acetic acid from simulated hemicellulosic hydrolysates containing xylose and sulfuric acid was attempted in a batch emulsion liquid membrane (ELM) system with organophosphorus extractants. Various experimental variables were used to develop a more energy-efficient ELM process. Total operation time of an ELM run with a very small quantity of trioctylphosphine oxide as the extractant was reduced to about a third of those required to attain almost the same extraction efficiency as obtained in previous ELM works without any extractant. Under specific conditions, acetic acid was selectively separated with a high degree of extraction and insignificant loss of xylose, and its purity and enrichment ratio in the stripping phase were higher than 92% and 6, respectively. Also, reused organic membrane solutions exhibited the extraction efficiency as high as fresh organic solutions did. These results showed that the current ELM process would be quite practical.

  15. Continued Advancement of Supported Liquid Membranes for Carbon Dioxide Control in Extravehicular Activity Applications

    NASA Technical Reports Server (NTRS)

    Wickham, David T.; Gleason, Kevin J.; Engel, Jeffrey R.; Cowley, Scott W.; Chullen, Cinda

    2015-01-01

    The development of a new, robust, portable life support system (PLSS) is a high priority for NASA in order to support longer and safer extravehicular activity (EVA) missions. One of the critical PLSS functions is maintaining the carbon dioxide (CO2) concentration in the suit at acceptable levels. Although the Metal Oxide (MetOx) canister has historically performed very well, it has a finite CO2 adsorption capacity. Therefore, the size and weight of the unit would have to be increased to extend EVA times. Consequently, new CO2 control technologies must be developed in order to meet mission objectives without increasing the size of the PLSS. Recent work has centered on sorbents that can be regenerated during the EVA; however, this strategy increases the system complexity and power consumption. A much simpler approach is to employ a membrane that vents CO2 to space and retains oxygen (O2). A membrane has many advantages over current technology: it is a continuous system with no limit on capacity, it requires no consumables, and it does not need any hardware to switch beds between absorption and regeneration. Unfortunately, conventional gas separation membranes do not have the needed selectivity for use in the PLSS. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a microporous material filled with a liquid that selectively reacts with CO2 over O2. In a recently completed Phase II SBIR project, Reaction Systems, Inc. achieved the required CO2 permeance and selectivity with an SLM in a flat sheet configuration. This paper describes work to convert the SLM into a more compact form and to scale it up to handle more representative process flow rates.

  16. Photoregenerative I-/I3- couple as a liquid cathode for proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Wang, Yadong; Ai, Xinping; Tu, Wenmao; Pan, Mu

    2014-10-01

    A photoassisted oxygen reduction reaction (ORR) through I-/I3- redox couple was investigated for proton exchange membrane (PEM) fuel cell cathode reaction. The I-/I3--based liquid cathode was used to replace conventional oxygen cathode, and its discharge product I- was regenerated to I3- by photocatalytic oxidation with the participation of oxygen. This new and innovative approach may provide a strategy to eliminate the usage of challenging ORR electrocatalysts, resulting in an avenue for developing low-cost and high-efficiency PEM fuel cells.

  17. Photo-osmosis through liquid membrane bilayers generated by [beta]-carotene coupled with bacteriorhodopsin

    SciTech Connect

    Madamwar, D.B.; Jain, N. )

    1992-11-01

    [beta]-carotene, a photosynthetic pigment isolated from the blue green algae Anabeana variabilis has been shown to exhibit the phenomenon of photo-osmosis through liquid membrane bilayers. In the authors search for new pigments that could show this phenomenon, they found [beta]-carotene also. When [beta]-carotene was combined with bacteriorhodopsin extracted from the extreme halophile Halobacterium halobium, the rate of photo-osmotic velocity was much higher than for either of these pigments independently. The rate of light induced volume flux depends on temperature, intensity, and wavelength of incident light and the nature and concentration of electron donors and acceptors. 10 refs., 2 figs., 3 tabs.

  18. Liquid membranes. (Latest citations from the US Patent Bibliographic file with exemplary claims). Published Search

    SciTech Connect

    Not Available

    1994-04-01

    The bibliography contains citations of selected patents concerning liquid membranes (LM) and LM processes. Included are patents for LM formulations and compositions, separation of aqueous and gas mixtures, and LM type electrodes. Applications are discussed, including use in drug release control, water and wastewater treatment, metal recovery, high temperature and high pressure LM processes, artificial LM lung and LM red cells, and LM scale removal from oil and gas production equipment. Citations concerning ion exchange resins are excluded and examined in a separate bibliography. (Contains a minimum of 99 citations and includes a subject term index and title list.)

  19. Liquid membranes. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1992-12-01

    The bibliography contains citations of selected patents concerning liquid membranes (LM) and LM processes. Included are patents for LM formulations and compositions, separation of aqueous and gas mixtures, and LM type electrodes. Applications are discussed, including use in drug release control, water and wastewater treatment, metal recovery, high temperature and high pressure LM processes, artificial LM lung and LM red cells, and LM scale removal from oil and gas production equipment. Citations concerning ion exchange resins are excluded and examined in a separate bibliography. (Contains a minimum of 92 citations and includes a subject term index and title list.)

  20. Note: Buoyant-force assisted liquid membrane electrochemical etching for nano-tip preparation

    NASA Astrophysics Data System (ADS)

    Zeng, Yongbin; Wang, Yufeng; Wu, Xiujuan; Xu, Kun; Qu, Ningsong

    2014-12-01

    A liquid membrane electrochemical etching process for preparing nano-tips is proposed by the introduction of buoyant force to the lower tip, in which the lower portion of the anodic wire is immersed into a floating layer. A mathematical model of this method is derived. Both calculation and experimental results demonstrate that the introduction of buoyant force can significantly decrease the tip radius. The lubricating oil and deionized water floating layers were tested for the processing of nano-tips. Further, high-aspect-ratio nano-electrodes were prepared by applying a relative vertical movement to the anodic wire.

  1. Effect of Ammonium- and Phosphonium-Based Ionic Liquids on the Separation of Lactic Acid by Supported Ionic Liquid Membranes (SILMs).

    PubMed

    Matsumoto, Michiaki; Panigrahi, Abhishek; Murakami, Yuuki; Kondo, Kazuo

    2011-05-13

    Biodegradable polymers have attracted much attention from an environmental point of view. Optically pure lactic acid that can be prepared by fermentation is one of the important raw materials for biodegradable polymer. The separation and purification of lactic acid from the fermentation broth are the major portions of the production costs. We proposed the application of supported ionic liquid membranes to recovering lactic acid. In this paper, the effect of ionic liquids, such as Aliquat 336, CYPHOS IL-101, CYPHOS IL-102, CYPHOS IL-104, CYPHOS IL-109 and CYPHOS IL-111 on the lactic acid permeation have been studied. Aliquat 336, CYPHOS IL-101 and CYPHOS IL-102 were found to be the best membrane solvents as far as membrane stability and permeation of lactic acid are concerned. CYPHOS IL-109 and CYPHOS IL-111 were found to be unsuitable, as they leak out from the pores of the supported liquid membrane (SLM), thereby allowing free transport of lactic acid as well as hydrochloric acid. CYPHOS IL-102 was found to be the most adequate (Permeation rate = 60.41%) among these ionic liquids as far as the separation of lactic acid is concerned. The permeation mechanisms, by which ionic liquid-water complexes act as the carrier of lactate and hydrochloric acid, were proposed. The experimental permeation results have been obtained as opposed to the expected values from the solution-diffusion mechanism.

  2. Membrane filtration of the liquid fraction from a solid-liquid separator for swine manure using a cationic polymer as flocculating agent.

    PubMed

    Masse, L; Mondor, M; Dubreuil, J

    2013-01-01

    The liquid fraction from a solid-liquid separator for swine manure, which used a cationic polymer to promote particle flocculation, was processed by one nanofiltration and two reverse osmosis spiral-wound membranes. Eight different liquid fraction batches (750 to 1750 L) were concentrated at volumetric concentration ratios (VCRs, initial to final volumes) ranging from 2.3 to 4.2. Membrane fouling intensity was highly variable, as water flux recovery after concentration cycles ranged from 13% to 88%. The most severe fouling was caused by a liquid fraction that had relatively low suspended solids (SS) (774 mg/L) and was concentrated at a low VCR of 2.6. Raw manure collected the same day also contained low SS, suggesting that fewer sites were available for polymer adsorption and thus more polymer remained in the liquid. However, because of the high opacity of the samples, residual polymer could not be detected in any feed or concentrate samples. Fouling was not totally irreversible as over 97% of membrane flux could be recovered by cleaning with acidic and alkaline solutions. Further tests with spiked liquid fractions indicated that fouling due to residual polymer in solution started to occur at a polymer concentration of 3 and 11 mg/L in initial and concentrated effluents, respectively. If a cationic polymer is used to pretreat manure, the amount of added polymer would have to be closely related to SS content as opposed to manure volume, in order to leave very little residual polymer in solution.

  3. A micro-immuno supported liquid membrane assay (mu-ISLMA).

    PubMed

    Tudorache, Madalina; Emnéus, Jenny

    2006-02-15

    A chemiluminescent (CL) based micro-immuno supported liquid membrane assay (mu-ISLMA) has been developed that enables clean up, enrichment and detection of simazine in a single miniaturised cartridge system. The mu-ISLM cartridge contains a supported liquid membrane (SLM) sandwiched between a donor and an acceptor plate (channel volumes 1.65 microL), the latter being covered by a thin layer of gold on to which anti-simazine antibodies were covalently immobilised via a self assembled monolayer (SAM) of either dithiobis(11-aminoundecane, hydrochloride) (DTAU) or beta-mercaptoethylamine (beta-MEA). The mu-ISLMA based on DTAU was characterised by both a high apparent extraction efficiency (E(app) = 136%) and high apparent enrichment factor (E(e)(app) = 544), which resulted in a very high sensitivity for simazine (LOD = 0.1 ng L(-1)). The paper discusses the influence of the different SAMs and three different anti-simazine-antibody preparations (polyclonal, affinity purified polyclonal and monoclonal) on the extraction parameters and assay sensitivity. The influence of the sample matrix (e.g. mineral water, orange juice and milk) on the simazine mu-ISLMA was also investigated.

  4. Hollow-fiber supported liquid membrane (HFSLM) for the separation of lanthanides and actinides

    SciTech Connect

    Mohapatra, P.K.; Ansari, S.A.; Bhattacharyya, A.; Manchanda, V.K.; Patil, C.B.

    2008-07-01

    The transport behavior of Nd(III) was investigated using hollow-fiber supported liquid membranes (HFSLM) from an acidic feed solution using N,N,N',N'-tetraoctyl-diglycolamide (TODGA) in normal paraffinic hydrocarbon (NPH) as the carrier. Near quantitative transport (>99%) of Nd(III) from 500 mL of feed containing 1 g/L Nd in 3.5 M HNO{sub 3} was possible in about 45 minutes. Quantitative transport time increased when the volume or Nd(III ) concentration in the feed was increased. The liquid membrane had excellent stability as indicated by eight consecutive runs that gave consistent transport rates. The HFSLM data using Cyanex- 301 in n-dodecane as carrier extractant for the lanthanide-actinide separation with the feed solution 1 M NaNO{sub 3} at pH 3.5 and stripping solution 0.01 M EDTA at a pH 3.5 were promising. (authors)

  5. Novel macrocyclic carriers for proton-coupled liquid membrane transport. Progress report, 1 December 1988--31 May 1991

    SciTech Connect

    Lamb, J.D.

    1991-06-10

    The objective of our research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period, including selenium-containing macrocycles, new crown-4 structures, and several new crown structures containing nitrogen based heterocycles as substituents in the principal macrocyclic ring. The cation binding properties of these macrocycles were investigated by potentiometric titration, calorimetric titration, solvent extraction, and NMR techniques. In addition, hydrophobic macrocycles were incorporated into dual hollow fiber membrane systems to investigate their membrane performance, especially in the proton-coupled transport mode. It was found that the dual hollow fiber system maintains the cation selectivity and permeability of supported liquid membranes, while enhancing membrane stability. The diffusion limited transport model was expanded to account for membrane solvent effects. Furthermore, Eu{sup 2+} transport was found to be similar to that of strontium and much higher than that of the lanthanides, in supported liquid membrane systems.

  6. Effect of storage duration on the rheological properties of goose liquid egg products and eggshell membranes.

    PubMed

    Kumbar, V; Nedomova, S; Trnka, J; Buchar, J; Pytel, R

    2016-07-01

    In practice, goose eggs are increasingly used and, therefore, the rheological properties have to be known for processing. The eggs of geese (Landes Goose, Anser anser f. domestica) were stored for one, 2, 3, 4, 6, and 8 wk at a constant temperature 4°C. First of all, the egg quality parameters were described in terms of egg weight, egg weight loss, egg shape index, yolk height, albumen height, yolk index, albumen index, and Haugh units. In the next step the rheological behavior of liquid egg products (egg yolk, albumen, and whole liquid egg) was studied using a concentric cylinder viscometer. Flow curves of all liquid egg products exhibited non-Newtonian shear thinning behavior. This behavior can be described using the Herschel-Bulkley model and for technical application using the Ostwald-de Waele model. The effect of the storage duration on the rheological behavior is different for the different liquid egg products. With the exception of very low shear rates, the viscosity of the egg yolk as well as of the whole liquid egg decreases with storage time. At lower shear rates there is a tendency toward increased albumen viscosity with storage duration. The storage duration also affects the mechanical properties of the eggshell membrane. This effect has been evaluated in terms of the ultimate tensile strength, fracture strain, and fracture toughness. All these parameters increased with the loading rate, but decreased during the egg storage. These mechanical phenomena should be respected, namely in the design of the egg model for the numerical simulation of the egg behavior under different kinds of the mechanical loading.

  7. High flux, positively charged loose nanofiltration membrane by blending with poly (ionic liquid) brushes grafted silica spheres.

    PubMed

    Yu, Liang; Zhang, Yatao; Wang, Yuanming; Zhang, Haoqin; Liu, Jindun

    2015-04-28

    Silica spheres modified by poly (ionic liquid) brushes, a novel positively charged nanomaterial is prepared by atom transfer radical polymerization (ATRP). A high flux positively charged loose nanofiltration membrane is fabricated via "blending-phase inversion" method. The morphology structures, hydrophilicity, thermal and mechanical properties, permeation performance of these membranes are investigated in detail. The results reveal that the hybrid membranes have enhanced surface hydrophilicity, water permeability, thermal stability, and mechanical properties. Characterization of membrane separation properties shows that the hybrid membranes possess higher salt permeability and relatively higher rejection for reactive dyes, which may open opportunities for the recycling of reactive dyes wastewater. Moreover, such hybrid membranes have an outstanding operational stability and salts concentration showed little effect on the separation properties.

  8. Novel macrocyclic carriers for proton-coupled liquid membrane transport. Final report

    SciTech Connect

    Lamb, J.D.; Izatt, R.M.; Bradshaw, J.S.; Shirts, R.B.

    1996-08-24

    The objective of this research program is to elucidate the chemical principles which are responsible for the cation selectivity and permeability of liquid membranes containing macrocyclic carriers. Several new macrocyclic carriers were synthesized during the last three year period. In addition, new, more convenient synthetic routes were achieved for several nitrogen-containing bicyclic and tricyclic macrocycles. The cation binding properties of these macrocycles were investigated by potentiometric titration, calorimetric titration, solvent extraction and NMR techniques. In addition, hydrophobic macrocycles were incorporated into dual hollow fiber and other membrane systems to investigate their membrane performance, especially in the proton-coupled transport mode. A study of the effect of methoxyalkyl macrocycle substituents on metal ion transport was completed. A new calorimeter was constructed which made it possible to study the thermodynamics of macrocycle-cation binding to very high temperatures. Measurements of thermodynamic data for the interaction of crown ethers with alkali and alkaline earth cations were achieved to 473 K. Molecular modeling work was begun for the first time on this project and fundamental principles were identified and developed for the establishment of working models in the future.

  9. Ionic Conductivity and Gas Permeability of Polymerized Ionic Liquid Block Copolymer Membranes

    NASA Astrophysics Data System (ADS)

    Evans, Christopher; Sanoja, Gabriel; Schneider, Yanika; Modestino, Miguel; Segalman, Rachel; Joint CenterArtificial Photosynthesis Team

    2014-03-01

    Polymer membranes for many energy applications, such as solar-to-hydrogen fuel production, require ionic conductivity while acting as gas diffusion barriers. We have synthesized a diblock copolymer consisting of poly(styrene-block-(4-(2-methacrylamidoethyl)-imidazolium trifluoroacetate) by treating poly(styrene-block-histamine methacrylamide) (PS- b-PHMA) with trifluoroacetic acid. The PS block serves as the structural support while the imidazolium derivative is an ion conducting polymerized ionic liquid (PIL). Small angle X-ray scattering and transmission electron microscopy demonstrate that the block copolymer self-assembles into well-ordered nanostructures, with lamellae and hexagonally packed cylindrical morphologies. The ionic conductivities of the PS-b-PHMA materials were as high as 2 x 10-4 S/cm while an order of magnitude increase in conductivity was observed upon conversion to PS-b-PIL. The ionic conductivity of the PS-b-PIL increased by a factor of ~ 4 up to 1.2 x 10-3 S/cm as the PIL domain size increased from 20 to 40 nm. These insights allow for the rational design of high performance ion conducting membranes with even greater conductivities via precise morphological control. Additionally, the role of thermal annealing on the ionic conductivity and gas permeability of copolymer membranes was investigated.

  10. Development of a supported liquid membrane as a nickel-zinc secondary battery separator

    SciTech Connect

    Poa, D.S.; Miller, J.F.; Yao, N.P.

    1985-05-01

    A liquid tertiary amine complexing agent is dissolved in an organic solvent and absorbed into and held within the pores of a microporous polymeric film (Celanese Celgard 2400 polypropylene) by either capillary or surface force. Screening tests were performed to identify the optimum tertiary amine/organic solvent combinations, as well as the optimum concentration range of the amine solutions. The treatment of Celgard 2400 microporous film with certain tertiary amine/organic solvent solutions, such as triethylamine/xylene or tripropylamine/xylene, had no significant effect on either zinc penetration resistivity (ZPR) or electrolytic resistivity of the membrane. When the film was treated with tri-n-octylamine solutions of very high amine concentration (above 75 vol %), the potential difference between the zinc cathode and the Ni(OH)/sub 2/ counter electrode, as well as the electrolytic resistance of the membrane, increased sharply (from 300 to 700%). Among the tertiary amine solutions tested in this study, trihexylamine/xylene, tri-n-octylamine (10 to 30 vol %)/toluene, and tri-n-octylamine (10 to 30 vol %)/xylene appeared to be the most promising, especially the last one. The treatment of the Celgard 2400 film with that solution increased the zinc penetration resistivity of the membrane by as much as 400%. Furthermore, this solution treatment also improved the electrolytic conductivity of the Celgard 2400 film.

  11. Development of a supported liquid membrane as a nickel-zinc secondary battery separator

    NASA Astrophysics Data System (ADS)

    Poa, D. S.; Miller, J. F.; Yao, N. P.

    1985-05-01

    A liquid tertiary amine complexing agent was dissolved in an organic solvent and absorbed into and held within the pores of a microporous polymeric film by either capillary or surface force. Screening tests were performed to identify the optimum tertiary amine/organic solvent combinations, and the optimum concentration range of the amine solutions. The treatment of Celgard 2400 microporous film with certain tertiary amine/organic solvent solutions, such as triethylamine/xylene or tripropylamine/xylene, had no significant effect on either zinc penetration resistivity (ZPR) or electrolytic resistivity of the membrane. When the film was treated with tri-n-octylamine solutions of very high amine concentration, the potential difference between the zinc cathode and the Ni(OH)2 counter electrode, the electrolytic resistance of the membrane, increased sharply. Among the tertiary amine solutions tested in this study, trihexylamine/xylene, tri-n-octylamine/toluene, and tri-n-octylamine/xylene appeared to be the most promising, especially the last one. The treatment of the Celgard 2400 film with that solution increased the zinc penetration resistivity of the membrane by as much as 400%. This solution treatment also improved the electrolytic conductivity of the Celgard 2400 film.

  12. Role of LiBF4 in Ionic Liquid Membranes for Facilitated CO2 Transport.

    PubMed

    Choi, Yeji; Hong, Gil Hwan; Kang, Sang Wook

    2016-03-01

    The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4)/LiBF4 electrolyte was prepared for highly selective facilitated CO2 transport membranes. When LiBF4 was incorporated into BMIM BF4, synergy effects by free Li+ ion and imidazolium cations is expected to enhance the separation performance for CO2/N2 and CO2/CH4. The free state of BF4- ions in BMIM BF4/LiBF4 solutions was investigated by FT-Raman spectroscopy. For the coordination of LiBF4 with BMIMBF4, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) was utilized. Electrolyte membranes consisting of BMIM BF4 and LiBF4 showed selectivities of 8.40 and 8.25 for CO2/N2 and CO2/CH4, respectively. Neat BMIM BF4 membrane showed selectivities of 5.0 and 4.8, respectively. Enhanced separation performance was attributed to increased free Li+ and abundant free imidazolium cations.

  13. Self-assembly of azobenzene bilayer membranes in binary ionic liquid-water nanostructured media.

    PubMed

    Kang, Tejwant Singh; Ishiba, Keita; Morikawa, Masa-aki; Kimizuka, Nobuo

    2014-03-11

    Anionic azobenzene-containing amphiphile 1 (sodium 4-[4-(N-methyl-N-dodecylamino)phenylazo]benzenesulfonate) forms ordered bilayer membranes in binary ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate, [C2mim][C2OSO3])-water mixtures. The binary [C2mim][C2OSO3]-water mixture is macroscopically homogeneous at any mixing ratio; however, it possesses fluctuating nanodomains of [C2mim][C2OSO3] molecules as observed by dynamic light scattering (DLS). These nanodomains show reversible heat-induced mixing behavior with water. Although the amphiphile 1 is substantially insoluble in pure water, it is dispersible in the [C2mim][C2OSO3]-water mixtures. The concentration of [C2mim][C2OSO3] and temperature exert significant influences on the self-assembling characteristics of 1 in the binary media, as shown by DLS, transmission electron microscopy (TEM), UV-vis spectroscopy, and zeta-potential measurements. Bilayer membranes with rod- or dotlike nanostructures were formed at a lower content of [C2mim][C2OSO3] (2-30 v/v %), in which azobenzene chromophores adopt parallel molecular orientation regardless of temperature. In contrast, when the content of [C2mim][C2OSO3] is increased above 60 v/v %, azobenzene bilayers showed thermally reversible gel-to-liquid crystalline phase transition. The self-assembly of azobenzene amphiphiles is tunable depending on the volume fraction of [C2mim][C2OSO3] and temperature, which are associated with the solvation by nanoclusters in the binary [C2mim][C2OSO3]-water media. These observations clearly indicate that mixtures of water-soluble ionic liquids and water provide unique and valiant environments for ordered molecular self-assembly.

  14. Liquid water transport characteristics of porous diffusion media in polymer electrolyte membrane fuel cells: A review

    NASA Astrophysics Data System (ADS)

    Liu, Xunliang; Peng, Fangyuan; Lou, Guofeng; Wen, Zhi

    2015-12-01

    Fundamental understanding of liquid water transport in gas diffusion media (GDM) is important to improve the material and structure design of polymer electrolyte membrane (PEM) fuel cells. Continuum methods of two-phase flow modeling facilitate to give more details of relevant information. The proper empirical correlations of liquid water transport properties, such as capillary characteristics, water relative permeability and effective contact angle, are crucial to two phase flow modeling and cell performance prediction. In this work, researches on these properties in the last decade are reviewed. Various efforts have been devoted to determine the water transport properties for GDMs. However, most of the experimental studies are ex-situ measurements. In-situ measurements for GDMs and extending techniques available to study the catalyst layer and the microporous layer will be further challenges. Using the Leverett-Udell correlation is not recommended for quantitative modeling. The reliable Leverett-type correlation for GDMs, with the inclusion of the cosine of effective contact angle, is desirable but hard to be established for modeling two-phase flow in GDMs. A comprehensive data set of liquid water transport properties is needed for various GDM materials under different PEM fuel cell operating conditions.

  15. RAFT synthesis of ABA triblock copolymers as ionic liquid-containing electroactive membranes.

    PubMed

    Wu, Tianyu; Wang, Dong; Zhang, Mingqiang; Heflin, James R; Moore, Robert B; Long, Timothy E

    2012-12-01

    2-(Dimethylamino)ethyl acrylate (DMAEA) imparts versatile functionality to poly[Sty-b-(nBA-co-DMAEA)-b-Sty] ABA triblock copolymers. A controlled synthetic strategy minimized chain transfer reactions and enabled the preparation of high-molecular-weight ABA triblock copolymers with relatively narrow PDIs between 1.39 and 1.44 using reversible addition-fragmentation chain transfer (RAFT) polymerization. The presence of tertiary amine functionality and their zwitterionic derivatives in the central blocks of the triblock copolymers afforded tunable polarity toward ionic liquids. Gravimetric measurements determined the swelling capacity of the triblock copolymers for ionic liquids (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIm TfO) and 1-ethyl-3-methylimidazolium ethylsulfate (EMIm ES). A correlation of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and small-angle X-ray scattering (SAXS) results revealed the impact of ionic liquid incorporation on the thermal transitions, thermomechanical properties, and morphologies of the triblock copolymers. IL-containing membranes of DMAEA-derived triblock copolymers and EMIm TfO exhibited desirable rubbery plateau moduli of ~100 MPa and electromechanical actuation to a 4 V electrical stimulus. Maintaining the mechanical ductility of polymer matrices while increasing their ion-conductivity is paramount for future electroactive devices.

  16. Selective removal and recovery of Black B reactive dye from simulated textile wastewater using the supported liquid membrane process.

    PubMed

    Harruddin, Norlisa; Othman, Norasikin; Ee Sin, Andeline Lim; Raja Sulaiman, Raja Norimie

    2015-01-01

    Effluent containing colour/dyes, especially reactive dyes, becomes a great concern of wastewater treatment because it is toxic to human life and aquatic life. In this study, reactive dye of Black B was separated using the supported liquid membrane process. Commercial polypropylene membrane was used as a support of the kerosene-tridodecylamine liquid membrane. Several parameters were tested and the result showed that almost 100% of 70 ppm Black B was removed and 99% of 70 ppm Black B was recovered at pH 2 of the feed phase containing 0.00001 M Na2SiO3, flow rate of 150 ml/min and 0.2 M NaOH. The membrane support also remained stable for up to 36 hours under an optimum condition.

  17. High-Permeance Room-Temperature Ionic-Liquid-Based Membranes for CO2/N-2 Separation

    SciTech Connect

    Zhou, JS; Mok, MM; Cowan, MG; McDanel, WM; Carlisle, TK; Gin, DL; Noble, RD

    2014-12-24

    We have developed and fabricated thin-film composite (TFC) membranes with an active layer consisting of a room-temperature ionic liquid/polymerized (room-temperature ionic liquid) [i.e., (RTIL)/poly(RTIL)] composite material. The resulting membrane has a CO2 permeance of 6100 +/- 400 GPU (where 1 GPU = 10(-6) cm(3)/(cm(2) s cmHg)) and an ideal CO2/N-2 selectivity of 22 +/- 2. This represents a new membrane with state-of-the-art CO2 permeance and good CO2/N-2 selectivity. To our knowledge, this is the first example of a TFC gas separation membrane composed of an RTIL-containing active layer.

  18. Influence of inorganic complexes on the transport of trace metals through permeation liquid membrane.

    PubMed

    Bayen, Stéphane; Gunkel-Grillon, Peggy; Worms, Isabelle; Martin, Michel; Buffle, Jacques

    2009-07-30

    Under specific conditions (pH, concentrations), trace metals may form, with environmental inorganic ligands, neutral complexes which, in principle, might diffuse passively through biological membranes or influence the response of (bio)analytical sensors for trace metals based on permeation liquid membrane (PLM). In this study, metal (Cu, Cd, Pb) transport through the planar PLM device was evaluated in the presence of major environmental inorganic ligands such as sulfate, carbonate and chloride under conditions where neutral complexes may be formed (up to 73% of neutral metal complex in the solution). In the presence of sulfate, comparison of predicted and experimental PLM fluxes of Cu, Pb and Cd, suggests that passive transport of neutral sulfate-metal complexes does not occur. This was confirmed by comparing fluxes in the presence and absence of carrier. In the presence of carbonate (for Cd, Cu and Pb) and chloride (for Pb and Cd), however, experimental PLM fluxes were greater than predicted (up to 4 and 25 times in the presence of carbonate and chloride, respectively), but experiments in the absence of carrier in the membrane revealed that no passive transport of neutral complexes (MCl(2) or MCO(3)) occurs through PLM. A possible mechanism is discussed. In parallel to the experiments with PLM, the influence of carbonate on the internalization fluxes of Cu(II) and Pb(II) by the freshwater algae, Chlamydomonas reinhardtii, was assessed. Similarly to the results of PLM, the fluxes of these two metals were larger than expected (based on the free metal ion activity model). Thus, even though PLM and bioaccumulation mechanisms are certainly different, similar unexpected behaviours occur for the metal transport through the PLM and biological membrane of C. reinhardtii, in the presence of carbonate.

  19. Supported liquid membrane-liquid chromatography-mass spectrometry analysis of cyanobacterial toxins in fresh water systems

    NASA Astrophysics Data System (ADS)

    Mbukwa, Elbert A.; Msagati, Titus A. M.; Mamba, Bhekie B.

    Harmful algal blooms (HABs) are increasingly becoming of great concern to water resources worldwide due to indiscriminate waste disposal habits resulting in water pollution and eutrophication. When cyanobacterial cells lyse (burst) they release toxins called microcystins (MCs) that are well known for their hepatotoxicity (causing liver damage) and have been found in eutrophic lakes, rivers, wastewater ponds and other water reservoirs. Prolonged exposure to low concentrated MCs are equally of health importance as they are known to be bioaccumulative and even at such low concentration do exhibit toxic effects to aquatic animals, wildlife and human liver cells. The application of common treatment processes for drinking water sourced from HABs infested reservoirs have the potential to cause algal cell lyses releasing low to higher amounts of MCs in finished water. Trace microcystins in water/tissue can be analyzed and quantified using Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) following solid-phase extraction (SPE) sample clean-up procedures. However, extracting MCs from algal samples which are rich in chlorophyll pigments and other organic matrices the SPE method suffers a number of drawbacks, including cartridge clogging, long procedural steps and use of larger volumes of extraction solvents. We applied a supported liquid membrane (SLM) based technique as an alternative sample clean-up method for LC-ESI-MS analysis of MCs from both water and algal cells. Four (4) MC variants (MC-RR, -YR, -LR and -WR) from lyophilized cells of Microcystis aeruginosa and water collected from a wastewater pond were identified) and quantified using LC-ESI-MS following a SLM extraction and liquid partitioning step, however, MC-WR was not detected from water extracts. Within 45 min of SLM extraction all studied MCs were extracted and pre-concentrated in approximately 15 μL of an acceptor phase at an optimal pH 2.02 of the donor phase (sample). The highest

  20. Hybrid biofilm-membrane bioreactor (Bf-MBR) for minimization of bulk liquid-phase organic substances and its positive effect on membrane permeability.

    PubMed

    Sun, F Y; Li, P; Li, J; Li, H J; Ou, Q M; Sun, T T; Dong, Z J

    2015-12-01

    Four biofilm membrane bioreactors (Bf-MBRs) with various fixed carrier volumes (C:M) were operated in parallel to investigate the effect of attached-growth mode biomass involvement to the change of liquid-phase organics characteristics and membrane permeability, by comparing with conventional MBR. The experiments displayed that C:M and co-existence of biofilm with suspended solids in Bf-MBRs resulted in slight difference in pollutants removal effectiveness, and in rather distinct biomass properties and bacterial activities. The membrane permeability and specific resistance of bulk suspension of Bf-MBRs related closely with the liquid-phase organic substance, including soluble microbial products (SMP) and biopolymer cluster (BPC). Compared with conventional MBR, Bf-MBR with proper C:M had a low total biomass content and food-chain, where biofilm formation and its dominance affected liquid-phase organics, especially through reducing their content and minimizing strongly and weakly hydrophobic components with small molecular weight, and thus to mitigate membrane fouling significantly.

  1. Modeling of facilitated transport of phenylalanine by emulsion liquid membranes with di(2-ethylhexyl)phosphoric acid as a carrier

    SciTech Connect

    Liu, X.; Liu, D.

    1998-12-01

    A mathematical model is developed in this paper to simulate the facilitated transport of phenylalanine (Phe) in emulsion liquid membrane (ELM) systems with di(2-ethylhexyl)phosphoric acid as a carrier. The model takes into account the mass transfer in both the external aqueous phase and the organic membrane phase interfacial reaction as well as membrane breakage during agitation. The model is tested by comparing theoretical predications with experimental results using Phe extraction by ELM processes. It is found that the model is valid for simulating the facilitated transport of Phe with ELM under various experimental conditions.

  2. Ionic liquid-based membranes as electrolytes for advanced lithium polymer batteries.

    PubMed

    Navarra, M A; Manzi, J; Lombardo, L; Panero, S; Scrosati, Bruno

    2011-01-17

    Gel-type polymer electrolytes are formed by immobilizing a solution of lithium N,N-bis(trifluoromethanesulfonyl)imide (LiTFSI) in N-n-butyl-N-ethylpyrrolidinium N,N-bis(trifluoromethanesulfonyl)imide (Py₂₄TFSI) ionic liquid (IL) with added mixtures of organic solvents, such as ethylene, propylene and dimethyl carbonates (EC, PC, and DMC, respectively), into a poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) matrix, and their properties investigated. The addition of the organic solvent mixtures results in an improvement of the ionic conductivity and in the stabilization of the interface with the lithium electrode. Conductivity values in the range of 10⁻³-10⁻²  S cm⁻¹ are obtained in a wide temperature range. These unique properties allow the effective use of these membranes as electrolytes for the development of advanced polymer batteries based on a lithium metal anode and an olivine-type lithium iron phosphate cathode.

  3. Effects of phosphonium-based ionic liquids on phospholipid membranes studied by small-angle X-ray scattering.

    PubMed

    Kontro, Inkeri; Svedström, Kirsi; Duša, Filip; Ahvenainen, Patrik; Ruokonen, Suvi-Katriina; Witos, Joanna; Wiedmer, Susanne K

    2016-12-01

    The effects of ionic liquids on model phospholipid membranes were studied by small-angle X-ray scattering, dynamic light scattering (DLS) and zeta potential measurements. Multilamellar 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes and large unilamellar vesicles composed of l-α-phosphatidylcholine (eggPC) and l-α-phosphatidylglycerol (eggPG) (80:20mol%) or eggPC, eggPG, and cholesterol (60:20:20mol%) were used as biomimicking membrane models. The effects of the phosphonium-based ionic liquids: tributylmethylphosphonium acetate, trioctylmethylphosphonium acetate, tributyl(tetradecyl)-phosphonium acetate, and tributyl(tetradecyl)-phosphonium chloride, were compared to those of 1-ethyl-3-methyl-imidazolium acetate. With multilamellar vesicles, the ionic liquids that did not disrupt liposomes decreased the lamellar spacing as a function of concentration. The magnitude of the effect depended on concentration for all studied ionic liquids. Using large unilamellar vesicles, first a slight decrease in the vesicle size, then aggregation of vesicles was observed by DLS for increasing ionic liquid concentrations. At concentrations just below those that caused aggregation of liposomes, large unilamellar vesicles were coated by ionic liquid cations, evidenced by a change in their zeta potential. The ability of phosphonium-based ionic liquids to affect liposomes is related to the length of the hydrocarbon chains in the cation. Generally, the ability of ionic liquids to disrupt liposomes goes hand in hand with inducing disorder in the phospholipid membrane. However, trioctylmethylphosphonium acetate selectively extracted and induced a well-ordered lamellar structure in phospholipids from disrupted cholesterol-containing large unilamellar vesicles. This kind of effect was not seen with any other combination of ionic liquids and liposomes.

  4. Integration of Nine Steps into One Membrane Reactor To Produce Synthesis Gases for Ammonia and Liquid Fuel.

    PubMed

    Li, Wenping; Zhu, Xuefeng; Chen, Shuguang; Yang, Weishen

    2016-07-18

    The synthesis of ammonia and liquid fuel are two important chemical processes in which most of the energy is consumed in the production of H2 /N2 and H2 /CO synthesis gases from natural gas (methane). Here, we report a membrane reactor with a mixed ionic-electronic conducting membrane, in which the nine steps for the production of the two types of synthesis gases are shortened to one step by using water, air, and methane as feeds. In the membrane reactor, there is no direct CO2 emission and no CO or H2 S present in the ammonia synthesis gas. The energy consumption for the production of the two synthesis gases can be reduced by 63 % by using this membrane reactor. This promising membrane reactor process has been successfully demonstrated by experiment.

  5. Separation of carbon dioxide from nitrogen or methane by supported ionic liquid membranes (SILMs): influence of the cation charge of the ionic liquid.

    PubMed

    Hojniak, Sandra D; Khan, Asim Laeeq; Hollóczki, Oldamur; Kirchner, Barbara; Vankelecom, Ivo F J; Dehaen, Wim; Binnemans, Koen

    2013-12-05

    Supported ionic liquid membranes (SILMs) are promising tools for the separation of carbon dioxide from other gases. In this paper, new imidazolium, pyrrolidinium, piperidinium, and morpholinium ionic liquids with a triethylene glycol side chain and tosylate anions, as well as their symmetrical dicationic analogues, have been synthesized and incorporated into SILMs. The selectivities for CO2/N2 and CO2/CH4 separations have been measured. The selectivities exhibited by the dicationic ionic liquids are up to two times higher than the values of the corresponding monocationic ionic liquids. Quantum chemical calculations have been used to investigate the difference in the interaction of carbon dioxide with monocationic and dicationic ionic liquids. The reason for the increased gas separation selectivity of the dicationic ionic liquids is two-fold: (1) a decrease in permeance of nitrogen and methane through the ionic liquid layer, presumably due to their less favorable interactions with the gases, while the permeance of carbon dioxide is reduced much less; (2) an increase in the number of interaction sites for the interactions with the quadrupolar carbon dioxide molecules in the dicationic ionic liquids, compared to the monocationic analogues.

  6. The use of Permeation Liquid Membrane (PLM) as an analytical tool for trace metal speciation studies in natural waters

    NASA Astrophysics Data System (ADS)

    Parthasarathy, N.; Pelletier, M.; Buffle, J.

    2003-05-01

    Permeation liquid membrane (PLM) based on liquid-liquid extraction principles is an emerging analytical tool for making in situ trace metal speciation measurements. A PLM comprising didecyl 1, 10 diaza crown etherlauric acid in phenylhexane/toluene has been developed for measuring free metal ions (e.g. Cu, Pb, Cd and Zn) concentration under natural water conditions. The capability of PLM for making speciation studies has been demonstrated using synthetic and natural ligands. Application of in situ preconcentration of trace metals in diverse waters using specially designed hollow fibre PLM are reported.

  7. Stabilized liquid membrane device (SLMD) for the passive, integrative sampling of labile metals in water

    USGS Publications Warehouse

    Brumbaugh, W.G.; Petty, J.D.; Huckins, J.N.; Manahan, S.E.

    2002-01-01

    A stabilized liquid membrane device (SLMD) is described for potential use as an in situ, passive, integrative sampler for cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in natural waters. The SLMD (patent pending) consists of a 2.5-cm-wide by 15-cm-long strip of low-density polyethylene (LDPE) layflat tubing containing 1 mL of an equal mixture (v/v) of oleic acid (cis-9-octadecenoic acid) and EMO-8Q (7-[4-ethyl-1-methyloctyl]-8-quinolinol). The reagent mixture continuously diffuses to the exterior surface of the LDPE membrane, and provides for sequestration of several divalent metals for up to several weeks. Depending on sampler configuration, concentration factors of several thousand can be realized for these metal ions after just a few days. In addition to in situ deployment, the SLMD may be useful for laboratory determination of labile metal species in grab samples. Methods for minimizing the effects of water flow on the sampling rate are currently under investigation.

  8. Aqueous liquid feed organic fuel cell using solid polymer electrolyte membrane

    NASA Technical Reports Server (NTRS)

    Surampudi, Subbarao (Inventor); Narayanan, Sekharipuram R. (Inventor); Vamos, Eugene (Inventor); Frank, Harvey A. (Inventor); Halpert, Gerald (Inventor); Olah, George A. (Inventor); Prakash, G. K. Surya (Inventor)

    1997-01-01

    A liquid organic fuel cell is provided which employs a solid electrolyte membrane. An organic fuel, such as a methanol/water mixture, is circulated past an anode of a cell while oxygen or air is circulated past a cathode of the cell. The cell solid electrolyte membrane is preferably fabricated from Nafion.TM.. Additionally, a method for improving the performance of carbon electrode structures for use in organic fuel cells is provided wherein a high surface-area carbon particle/Teflon.TM.-binder structure is immersed within a Nafion.TM./methanol bath to impregnate the electrode with Nafion.TM.. A method for fabricating an anode for use in a organic fuel cell is described wherein metal alloys are deposited onto the electrode in an electro-deposition solution containing perfluorooctanesulfonic acid. A fuel additive containing perfluorooctanesulfonic acid for use with fuel cells employing a sulfuric acid electrolyte is also disclosed. New organic fuels, namely, trimethoxymethane, dimethoxymethane, and trioxane are also described for use with either conventional or improved fuel cells.

  9. Mixed reverse micelles facilitated downstream processing of lipase involving water-oil-water liquid emulsion membrane.

    PubMed

    Bhowal, Saibal; Priyanka, B S; Rastogi, Navin K

    2014-01-01

    Our earlier work for the first time demonstrated that liquid emulsion membrane (LEM) containing reverse micelles could be successfully used for the downstream processing of lipase from Aspergillus niger. In the present work, we have attempted to increase the extraction and purification fold of lipase by using mixed reverse micelles (MRM) consisting of cationic and nonionic surfactants in LEM. It was basically prepared by addition of the internal aqueous phase solution to the organic phase followed by the redispersion of the emulsion in the feed phase containing enzyme, which resulted in globules of water-oil-water (WOW) emulsion for the extraction of lipase. The optimum conditions for maximum lipase recovery (100%) and purification fold (17.0-fold) were CTAB concentration 0.075 M, Tween 80 concentration 0.012 M, at stirring speed of 500 rpm, contact time 15 min, internal aqueous phase pH 7, feed pH 9, KCl concentration 1 M, NaCl concentration 0.1 M, and ratio of membrane emulsion to feed volume 1:1. Incorporation of the nonionic surfactant (e.g., Tween 80) resulted in remarkable improvement in the purification fold (3.1-17.0) of the lipase. LEM containing a mixture of nonionic and cationic surfactants can be successfully used for the enhancement in the activity recovery and purification fold during downstream processing of enzymes/proteins.

  10. Metal nanoparticle/ionic liquid/cellulose: new catalytically active membrane materials for hydrogenation reactions.

    PubMed

    Gelesky, Marcos A; Scheeren, Carla W; Foppa, Lucas; Pavan, Flavio A; Dias, Silvio L P; Dupont, Jairton

    2009-07-13

    Transition metal-containing membrane films of 10, 20, and 40 μm thickness were obtained by the combination of irregularly shaped nanoparticles with monomodal size distributions of 4.8 ± 1.1 nm (Rh(0)) and 3.0 ± 0.4 nm (Pt(0)) dispersed in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (BMI·(NTf)(2)) with a syrup of cellulose acetate (CA) in acetone. The Rh(0) and Pt(0) metal concentration increased proportionally with increases in film thickness up to 20 μm, and then the material became metal saturated. The presence of small and stable Rh(0) or Pt(0) nanoparticles induced an augmentation in the CA/IL film surface areas. The augmentation of the IL content resulted in an increase of elasticity and decrease in tenacity and toughness, whereas the stress at break was not influenced. The introduction of IL probably causes an increase in the separation between the cellulose macromolecules that results in a higher flexibility, lower viscosity, and better formability of the cellulose material. The nanoparticle/IL/CA combinations exhibit an excellent synergistic effect that enhances the activity and durability of the catalyst for the hydrogenation of cyclohexene. The nanoparticle/IL/cellulose acetate film membranes display higher catalytic activity (up to 7353 h(-1) for the 20 μm film of CA/IL/Pt(0)) and stability than the nanoparticles dispersed only in the IL.

  11. Treatment of cyanide wastewater by bulk liquid membrane using tricaprylamine as a carrier.

    PubMed

    Li, Guoping; Xue, Juanqin; Liu, Nina; Yu, Lihua

    2016-01-01

    The transport of cyanide from wastewater through a bulk liquid membrane (BLM) containing tricaprylamine (TOA) as a carrier was studied. The effect of cyanide concentration in the feed solution, TOA concentration in the organic phase, the stirring speed, NaOH concentration in the stripping solution and temperature on cyanide transport was determined through BLM. Mass transfer of cyanide through BLM was analyzed by following the kinetic laws of two consecutive irreversible first-order reactions, and the kinetic parameters (k(1), k(2), R(m)(max), t(max), J(a)(max), J(d)(max)) were also calculated. Apparently, increase in membrane entrance (k(1)) and exit rate (k(2)) constants was accompanied by a rise in temperature. The values of activation energies were obtained as 35.6 kJ/mol and 18.2 kJ/mol for removal and recovery, respectively. These values showed that both removal and recovery steps in cyanide transport is controlled by the rate of the chemical complexation reaction. The optimal reaction conditions were determined by BLM using trioctylamine as the carrier: feed phase: pH 4, carrier TOA possession ratio in organic phase: 2% (V/V), stripping phase concentration of NaOH: 1% (W/V), reaction time: 60 min, stirring speed: 250 r/min. Under the above conditions, the removal rate was up to 92.96%. The experiments demonstrated that TOA was a good carrier for cyanide transport through BLM in this study.

  12. Electromechanical performance and membrane stability of novel ionic polymer transducers constructed in the presence of ionic liquids

    NASA Astrophysics Data System (ADS)

    Duncan, Andrew J.; Leo, Donald J.; Long, Timothy E.; Akle, Barbar J.; Park, Jong K.; Moore, Robert B.

    2009-03-01

    Ionic polymer transducers (IPT) are a class of devices that leverage electroactive polymers (EAP), specifically electrolyte-swollen ionomeric membranes, to perform energy conversions. Energy transformation from input to output is referred to as transduction and occurs between the electrical and mechanical domains. The present study expands on IPT investigations with a novel series of sulfonated polysulfones (sBPS), with specific interest in the effect of polymer topology on actuator performance. A hydrophilic ionic liquid was combined with a series of sBPS through a casting method to create hydrated membranes that contained target uptakes (f) of the diluent. The ionic liquid's hydrophilic, yet organic nature raised the issue of its degree of compatibility and miscibility with the microphase separated domains of the host ionomeric membrane. Initial studies of the ionomer - ionic liquid morphology were performed with synchrotron small angle X-ray scattering (SAXS). The effective plasticization of the membranes was identified with dynamic mechanical analysis (DMA) in terms of varied storage modulus and thermal transitions with ionic liquid uptake. Electrical impedance spectroscopy (EIS) was employed to quantify the changes in ionic conductivity for each sBPS ionomer across a range of uptake. Combined results from these techniques implied that the presence of large amounts of ionic liquid swelled the hydrophilic domains of the ionomer and greatly increased the ionic conductivity. Decreases in storage modulus and the glass transition temperature were proportional to one another but of a lesser magnitude than changes in conductivity. The present range of ionic liquid uptake for sBPS was sufficient to identify the critical uptake (fc) for three of the four ionomers in the series. Future work to construct IPTs with these components will use the critical uptake as a minimum allowable content of ionic liquid to optimize the balance of electrical and mechanical properties for

  13. Molecular dynamics simulations of a fully hydrated dimyristoylphosphatidylcholine membrane in liquid-crystalline phase

    NASA Astrophysics Data System (ADS)

    Zubrzycki, Igor Z.; Xu, Yan; Madrid, Marcela; Tang, Pei

    2000-02-01

    Molecular dynamics (MD) simulations were performed to investigate the structure of a fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayer in liquid-crystalline (fluid) phase at 30 °C. The bilayer consists of 200 DMPC lipid molecules with nw=27.4 water molecules per lipid. The membrane was built with reference to the coordinates of a previously published 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane patch. A four-step dynamic procedure (110 ps) with Berendsen pressure rescaling (P=0 and 1 bar), applied in all three directions, was used to rapidly prepare the bilayer. This system was then subjected to two separate constant pressure and temperature simulations at 1 bar and 30 °C for ˜380 ps, using the Nosé-Hoover NPT method with periodical boundaries and Berendsen temperature and pressure rescaling method, respectively. The resultant bilayer has an area per lipid of 59.2 Å2 and a head-to-head thickness (DHH) of 36.3 Å. These values are in good agreement with the x-ray diffraction data of 59.7 Å2 and 34.4 Å, respectively, for DMPC at 30 °C with nw of 25.7 [H. I. Petrache, S. Tristram-Nagle, and J. F. Nagle, Chem. Phys. Lipids 95, 83 (1998)]. The fractions of trans and gauche bonds in the hydrocarbon chains, averaged for the last 94 ps of simulation, are 81.7% and 18.3%, respectively, suggesting a fluid phase of the membrane. The electron density profile resembles closely that measured by x-ray diffraction. Water density profile suggests a significant penetration of water molecules into the bilayer head region to as deep as the carbonyl groups, with phosphate groups being strongly hydrated.

  14. Metal-organic framework supported ionic liquid membranes for CO2 capture: anion effects.

    PubMed

    Gupta, Krishna M; Chen, Yifei; Hu, Zhongqiao; Jiang, Jianwen

    2012-04-28

    IRMOF-1 supported ionic liquid (IL) membranes are investigated for CO(2) capture by atomistic simulation. The ILs consist of identical cation 1-n-butyl-3-methylimidazolium [BMIM](+), but four different anions, namely hexafluorophosphate [PF(6)](-), tetrafluoroborate [BF(4)](-), bis(trifluoromethylsulfonyl)imide [Tf(2)N](-), and thiocyanate [SCN](-). As compared with the cation, the anion has a stronger interaction with IRMOF-1 and a more ordered structure in IRMOF-1. The small anions [PF(6)](-), [BF(4)](-), and [SCN](-) prefer to locate near to the metal-cluster, particularly the quasi-spherical [PF(6)](-) and [BF(4)](-). In contrast, the bulky and chain-like [BMIM](+) and [Tf(2)N](-) reside near the phenyl ring. Among the four anions, [Tf(2)N](-) has the weakest interaction with IRMOF-1 and thus the strongest interaction with [BMIM](+). With increasing the weight ratio of IL to IRMOF-1 (W(IL/IRMOF-1)), the selectivity of CO(2)/N(2) at infinite dilution is enhanced. At a given W(IL/IRMOF-1), the selectivity increases as [Tf(2)N](-) < [PF(6)](-) < [BF(4)](-) < [SCN](-). This hierarchy is predicted by the COSMO-RS method, and largely follows the order of binding energy between CO(2) and anion estimated by ab initio calculation. In the [BMIM][SCN]/IRMOF-1 membrane with W(IL/IRMOF-1) = 1, [SCN](-) is identified to be the most favorable site for CO(2) adsorption. [BMIM][SCN]/IRMOF-1 outperforms polymer membranes and polymer-supported ILs in CO(2) permeability, and its performance surpasses Robeson's upper bound. This simulation study reveals that the anion has strong effects on the microscopic properties of ILs and suggests that MOF-supported ILs are potentially intriguing for CO(2) capture.

  15. Improvement of Aconitum napellus micropropagation by liquid culture on floating membrane rafts.

    PubMed

    Watad, A A; Kochba, M; Nissim, A; Gaba, V

    1995-03-01

    An efficient method was developed using floating membrane rafts (Liferaft(™)) for the micropropagation of Aconitum napellus (Ranunculaceae), a cut flower crop with a low natural propagation rate. This was achieved by introducing shoot tips into culture on Murashige and Skoog's (1962) solid medium, or liquid medium-supported rafts, supplemented by different levels of benzyl adenine (BA). Optimum shoot proliferation on solid medium required 4mg/l BA, whereas for expiants supported on rafts optimal proliferation was achieved at 0.25mg/l BA. Maximum shoot proliferation was found using the floating rafts (propagation ratio of 4.2 per month), 45% higher than the maximum value on solid medium. A similar value could be obtained on solid medium after a period of 2 months. The optimal response to BA was similar for fresh weight gain and shoot length. Growth in a shallow layer of liquid in shake flasks gives a similar shoot multiplication rate to that on floating rafts; however, submerged leaves brown and die.

  16. A 2D-ELDOR study of the liquid ordered phase in multilamellar vesicle membranes.

    PubMed

    Costa-Filho, Antonio J; Shimoyama, Yuhei; Freed, Jack H

    2003-04-01

    2D-ELDOR spectroscopy has been employed to study the dynamic structure of the liquid-ordered (Lo) phase versus that of the liquid-crystalline (Lc) phase in multibilayer phospholipid vesicles without (Lc) and with (Lo) cholesterol, using end-chain and headgroup labels and spin-labeled cholestane. The spectra are in most cases found to be dramatically different for these two phases. Thus, visual inspection of the 2D-ELDOR spectra provides a convenient way to distinguish the two phases in membranes. Detailed analysis shows these observations are due to increased ordering in the Lo phase and modified reorientation rates. In the Lo phase, acyl chains undergo a faster rotational diffusion and higher ordering than in the Lc phase, whereas spin-labeled cholestane exhibits slower rotational diffusion and higher ordering. On the other hand, the choline headgroup in the Lo phase exhibits faster motion and reduced but realigned ordering versus the Lc phase. The microscopic translational diffusion rates in the Lo phase are significantly reduced in the presence of cholesterol. These results are compared with previous studies, and a consistent model is provided for interpreting them in terms of the differences in the dynamic structure of the Lo and Lc phases.

  17. Ionic Liquids as the MOFs/Polymer Interfacial Binder for Efficient Membrane Separation.

    PubMed

    Lin, Rijia; Ge, Lei; Diao, Hui; Rudolph, Victor; Zhu, Zhonghua

    2016-11-23

    Obtaining strong interfacial affinity between filler and polymer is critical to the preparation of mixed matrix membranes (MMMs) with high separation efficiency. However, it is still a challenge for micron-sized metal organic frameworks (MOFs) to achieve excellent compatibility and defect-free interface with polymer matrix. Thin layer of ionic liquid (IL) was immobilized on micron-sized HKUST-1 to eliminate the interfacial nonselective voids in MMMs with minimized free ionic liquid (IL) in polymer matrix, and then the obtained IL decorated HKUST-1 was incorporated into 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-2,3,5,6-tetramethyl-1,3-phenyldiamine (6FDA-Durene) to fabricate MMMs. Acting as a filler/polymer interfacial binder, the favorable MOF/IL and IL/polymer interaction can facilitate the enhancement of MOF/polymer affinity. Compared to MMM with only HKUST-1 incorporation, MMM with IL decorated HKUST-1 succeeded in restricting the formation of nonselective interfacial voids, leading to an increment in CO2 selectivity. The IL decoration method can be an effective approach to eliminate interfacial voids in MMMs, extending the filler selection to a wide range of large-sized fillers.

  18. A 2D-ELDOR Study of the Liquid Ordered Phase in Multilamellar Vesicle Membranes

    PubMed Central

    Costa-Filho, Antonio J.; Shimoyama, Yuhei; Freed, Jack H.

    2003-01-01

    2D-ELDOR spectroscopy has been employed to study the dynamic structure of the liquid-ordered (Lo) phase versus that of the liquid-crystalline (Lc) phase in multibilayer phospholipid vesicles without (Lc) and with (Lo) cholesterol, using end-chain and headgroup labels and spin-labeled cholestane. The spectra are in most cases found to be dramatically different for these two phases. Thus, visual inspection of the 2D-ELDOR spectra provides a convenient way to distinguish the two phases in membranes. Detailed analysis shows these observations are due to increased ordering in the Lo phase and modified reorientation rates. In the Lo phase, acyl chains undergo a faster rotational diffusion and higher ordering than in the Lc phase, whereas spin-labeled cholestane exhibits slower rotational diffusion and higher ordering. On the other hand, the choline headgroup in the Lo phase exhibits faster motion and reduced but realigned ordering versus the Lc phase. The microscopic translational diffusion rates in the Lo phase are significantly reduced in the presence of cholesterol. These results are compared with previous studies, and a consistent model is provided for interpreting them in terms of the differences in the dynamic structure of the Lo and Lc phases. PMID:12668470

  19. Ionic-liquid-based proton conducting membranes for anhydrous H2/Cl2 fuel-cell applications.

    PubMed

    Liu, Sa; Zhou, Li; Wang, Pengjie; Zhang, Fangfang; Yu, Shuchun; Shao, Zhigang; Yi, Baolian

    2014-03-12

    An ionic-liquid-doped poly(benzimidazole) (PBI) proton-conducting membrane for an anhydrous H2/Cl2 fuel cell has been proposed. Compared with other ionic liquids, such as imidazole-type ionic liquids, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) showed better electrode reaction kinetics (H2 oxidation and Cl2 reduction reaction at platinum) and was more suitable for a H2/Cl2 fuel cell. PBI polymer and [dema][TfO] were compatible with each other, and the hybrid membranes exhibited high stability and good ionic conductivity, reaching 20.73 mS cm(-1) at 160 °C. We also analyzed the proton-transfer mechanism in this ionic-liquid-based membrane and considered that both proton-hopping and diffusion mechanisms existed. In addition, this composite electrolyte worked well in a H2/Cl2 fuel cell under non-water conditions. This work would give a good path to study the novel membranes for anhydrous H2/Cl2 fuel-cell application.

  20. Parallel artificial liquid membrane extraction of new psychoactive substances in plasma and whole blood.

    PubMed

    Vårdal, Linda; Askildsen, Hilde-Merete; Gjelstad, Astrid; Øiestad, Elisabeth Leere; Edvardsen, Hilde Marie Erøy; Pedersen-Bjergaard, Stig

    2017-03-24

    Parallel artificial liquid membrane extraction (PALME) was combined with ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS) and the potential for screening of new psychoactive substances (NPS) was investigated for the first time. PALME was performed in 96-well format comprising a donor plate, a supported liquid membrane (SLM), and an acceptor plate. Uncharged NPS were extracted from plasma or whole blood, across an organic SLM, and into an aqueous acceptor solution, facilitated by a pH gradient. MDAI (5,6-methylenedioxy-2-aminoindane), methylone, PFA (para-fluoroamphetamine), mCPP (meta-chlorophenylpiperazine), pentedrone, methoxetamine, MDPV (methylenedioxypyrovalerone), ethylphenidate, 2C-E (2,5-dimethoxy-4-ethylphenethylamine), bromo-dragonfly, and AH-7921 (3,4-dichloro-N-{[1-(dimethylamino)cyclohexyl]methyl}benzamide) were selected as representative NPS. Optimization of operational parameters was necessary as the NPS were novel to PALME, and because PALME was performed from whole blood for the very first time. In the PALME method developed for plasma, NPS were extracted from a 250μL alkalized donor solution consisting of 125μL plasma sample, 115μL 40mM NaOH, and 10μL internal standard. In the PALME method from whole blood, the 250μL alkalized donor solution consisted of 100μL whole blood, 50μL deionized water, 75μL 80mM NaOH, and 25μL internal standard. In both methods, extraction was accomplished across an SLM of 5μL dodecyl acetate with 1% trioctylamine (w/w), and further into an acidic acceptor solution of 50μL 20mM formic acid. The extraction was promoted by agitation at 900rpm and was carried out for 120min. Method validation was performed and the following parameters were considered: linearity, limits of quantification (LOQ), intra- and inter-day precision, accuracy, extraction recoveries, carry-over, and matrix effects. The validation results were in accordance with FDA guidelines.

  1. High temperature ceramic membrane reactors for coal liquid upgrading. Final report, September 21, 1989--November 20, 1992

    SciTech Connect

    Tsotsis, T.T.; Liu, P.K.T.; Webster, I.A.

    1992-12-31

    Membrane reactors are today finding extensive applications for gas and vapor phase catalytic reactions (see discussion in the introduction and recent reviews by Armor [92], Hsieh [93] and Tsotsis et al. [941]). There have not been any published reports, however, of their use in high pressure and temperature liquid-phase applications. The idea to apply membrane reactor technology to coal liquid upgrading has resulted from a series of experimental investigations by our group of petroleum and coal asphaltene transport through model membranes. Coal liquids contain polycyclic aromatic compounds, which not only present potential difficulties in upgrading, storage and coprocessing, but are also bioactive. Direct coal liquefaction is perceived today as a two-stage process, which involves a first stage of thermal (or catalytic) dissolution of coal, followed by a second stage, in which the resulting products of the first stage are catalytically upgraded. Even in the presence of hydrogen, the oil products of the second stage are thought to equilibrate with the heavier (asphaltenic and preasphaltenic) components found in the feedstream. The possibility exists for this smaller molecular fraction to recondense with the unreacted heavy components and form even heavier undesirable components like char and coke. One way to diminish these regressive reactions is to selectively remove these smaller molecular weight fractions once they are formed and prior to recondensation. This can, at least in principle, be accomplished through the use of high temperature membrane reactors, using ceramic membranes which are permselective for the desired products of the coal liquid upgrading process. An additional incentive to do so is in order to eliminate the further hydrogenation and hydrocracking of liquid products to undesirable light gases.

  2. Helfrich model of membrane bending: from Gibbs theory of liquid interfaces to membranes as thick anisotropic elastic layers.

    PubMed

    Campelo, Felix; Arnarez, Clement; Marrink, Siewert J; Kozlov, Michael M

    2014-06-01

    Helfrich model of membrane bending elasticity has been most influential in establishment and development of Soft-Matter Physics of lipid bilayers and biological membranes. Recently, Helfrich theory has been extensively used in Cell Biology to understand the phenomena of shaping, fusion and fission of cellular membranes. The general background of Helfrich theory on the one hand, and the ways of specifying the model parameters on the other, are important for quantitative treatment of particular biologically relevant membrane phenomena. Here we present the origin of Helfrich model within the context of the general Gibbs theory of capillary interfaces, and review the strategies of computing the membrane elastic moduli based on considering a lipid monolayer as a three-dimensional thick layer characterized by trans-monolayer profiles of elastic parameters. We present the results of original computations of these profiles by a state-of-the-art numerical approach.

  3. Opto-mechanical analysis of nonlinear elastomer membrane deformation under hydraulic pressure for variable-focus liquid-filled microlenses.

    PubMed

    Choi, Seung Tae; Son, Byeong Soo; Seo, Gye Won; Park, Si-Young; Lee, Kyung-Sick

    2014-03-10

    Nonlinear large deformation of a transparent elastomer membrane under hydraulic pressure was analyzed to investigate its optical performance for a variable-focus liquid-filled membrane microlens. In most membrane microlenses, actuators control the hydraulic pressure of optical fluid so that the elastomer membrane together with the internal optical fluid changes its shape, which alters the light path of the microlens to adapt its optical power. A fluid-structure interaction simulation was performed to estimate the transient behavior of the microlens under the operation of electroactive polymer actuators, demonstrating that the viscosity of the optical fluid successfully stabilizes the fluctuations within a fairly short period of time during dynamic operations. Axisymmetric nonlinear plate theory was used to calculate the deformation profile of the membrane under hydrostatic pressure, with which optical characteristics of the membrane microlens were estimated. The effects of gravitation and viscoelastic behavior of the elastomer membrane on the optical performance of the membrane microlens were also evaluated with finite element analysis.

  4. Design of pervaporation membrane for organic-liquid separation based on solubility control by plasma-graft filling polymerization technique

    SciTech Connect

    Yamaguchi, Takeo; Nakao, Shinichi; Kimura, Shoji )

    1993-05-01

    Pervaporation performance through the membranes showed the same tendency as solubility results. The authors have prepared the filling-polymerized membrane for pervaporation of organic-liquid mixtures by the plasma-graft polymerization technique. The membrane is composed of two different polymers: a porous substrate which can suppress membrane swelling and a grafted polymer which forms in the pores of the substrate and exhibits selectivity due to its solubility. The objectives of the present study are to design a suitable membrane for an organic-mixture system by the control of the filling-polymer solubility. Specifically, a porous high-density polyethylene membrane and poly(methylacrylate/acrylamide) copolymer were employed as the porous substrate and grafted polymer, respectively, and grafted copolymer solubility was predicted by Hansen solubility parameters (HSP). The grafted polymer composition and its solubility behavior could be controlled by varying the monomer composition, and the solubility change was in accordance with the prediction by HSP. Pervaporation performance through the membranes showed the same tendency as solubility results. The authors concluded that an optimum pervaporation membrane can be designed on the basis of solubility control through use of these techniques for polymerization and prediction.

  5. Interactions of lipid-based liquid crystalline nanoparticles with model and cell membranes.

    PubMed

    Barauskas, Justas; Cervin, Camilla; Jankunec, Marija; Spandyreva, Marija; Ribokaite, Kristina; Tiberg, Fredrik; Johnsson, Markus

    2010-05-31

    Lipid-based liquid crystalline nanoparticles (LCNPs) are interesting candidates for drug delivery applications, for instance as solubilizing or encapsulating carriers for intravenous (i.v.) drugs. Here it is important that the carriers are safe and tolerable and do not have, e.g. hemolytic activity. In the present study we have studied LCNP particles of different compositions with respect to their mixing behavior and membrane destabilizing effects in model and cell membrane systems. Different types of non-lamellar LCNPs were studied including cubic phase nanoparticles (Cubosome) based on glycerol monooleate (GMO), hexagonal phase nanoparticles (Hexosome) based on diglycerol monooleate (DGMO) and glycerol dioleate (GDO), sponge phase nanoparticles based on DGMO/GDO/polysorbate 80 (P80) and non-lamellar nanoparticles based on soy phosphatidylcholine (SPC)/GDO. Importantly, the LCNPs based on the long-chain monoacyl lipid, GMO, were shown to display a very fast and complete lipid mixing with model membranes composed of multilamellar SPC liposomes as assessed by a fluorescence energy transfer (FRET) assay. The result correlated well with pronounced hemolytic properties observed when the GMO-based LCNPs were mixed with rat whole blood. In sharp contrast, LCNPs based on mixtures of the long-chain diacyl lipids, SPC and GDO, were found to be practically inert towards both hemolysis in rat whole blood as well as lipid mixing with SPC model membranes. The LCNP dispersions based on a mixture of long-chain monoacyl and diacyl lipids, DGMO/GDO, displayed an intermediate behavior compared to the GMO and SPC/GDO-based systems with respect to both hemolysis and lipid mixing. It is concluded that GMO-based LCNPs are unsuitable for parenteral drug delivery applications (e.g. i.v. administration) while the SPC/GDO-based LCNPs exhibit good properties with limited lipid mixing and hemolytic activity. The correlation between results from lipid mixing or FRET experiments and the in

  6. Systematic cyanobacterial membrane proteome analysis by combining acid hydrolysis and digestive enzymes with nano-liquid chromatography-Fourier transform mass spectrometry.

    PubMed

    Kwon, Joseph; Oh, Jeehyun; Park, Chiyoul; Cho, Kun; Kim, Seung Il; Kim, Soohyun; Lee, Sunghoon; Bhak, Jong; Norling, Birgitta; Choi, Jong-Soon

    2010-01-15

    The identification of membrane proteins is currently under-represented since the trans-membrane domains of membrane proteins have a hydrophobic property. Membrane proteins have mainly been analyzed by cleaving and identifying exposed hydrophilic domains. We developed the membrane proteomics method for targeting integral membrane proteins by the following sequential process: in-solution acid hydrolysis, reverse phase chromatographic separation, trypsin or chymotrypsin digestion and nano-liquid chromatography-Fourier transform mass spectrometry. When we employed total membrane proteins of Synechocystis sp. PCC 6803, 155 integral membrane proteins out of a predictable 706 were identified in a single application, corresponding to 22% of a genome. The combined methods of acid hydrolysis-trypsin (AT) and acid hydrolysis-chymotrypsin (AC) identified both hydrophilic and hydrophobic domains of integral membrane proteins, respectively. The systematic approach revealed a more concrete data in mapping the repertoire of cyanobacterial membrane and membrane-linked proteome.

  7. Liquid-liquid-solid microextraction based on membrane-protected molecularly imprinted polymer fiber for trace analysis of triazines in complex aqueous samples.

    PubMed

    Hu, Yuling; Wang, Yangyang; Hu, Yufei; Li, Gongke

    2009-11-20

    A novel liquid-liquid-solid microextraction (LLSME) technique based on porous membrane-protected molecularly imprinted polymer (MIP)-coated silica fiber has been developed. In this technique, a MIP-coated silica fiber was protected with a length of porous polypropylene hollow fiber membrane which was filled with water-immiscible organic phase. Subsequently the whole device was immersed into aqueous sample for extraction. The LLSME technique was a three-phase microextraction approach. The target analytes were firstly extracted from the aqueous sample through a few microliters of organic phase residing in the pores and lumen of the membrane, and were then finally extracted onto the MIP fiber. A terbutylazine MIP-coated silica fiber was adopted as an example to demonstrate the feasibility of the novel LLSME method. The extraction parameters such as the organic solvent, extraction and desorption time were investigated. Comparison of the LLSME technique was made with molecularly imprinted polymer based solid-phase microextraction (MIP-SPME) and hollow fiber membrane-based liquid-phase microextraction (HF-LPME), respectively. The LLSME, integrating the advantages of high selectivity of MIP-SPME and enrichment and sample cleanup capability of the HF-LPME into a single device, is a promising sample preparation method for complex samples. Moreover, the new technique overcomes the problem of disturbance from water when the MIP-SPME fiber was exposed directly to aqueous samples. Applications to analysis of triazine herbicides in sludge water, watermelon, milk and urine samples were evaluated to access the real sample application of the LLSME method by coupling with high-performance liquid chromatography (HPLC). Low limits of detection (0.006-0.02 microg L(-1)), satisfactory recoveries and good repeatability for real sample (RSD 1.2-9.6%, n = 5) were obtained. The method was demonstrated to be a fast, selective and sensitive pretreatment method for trace analysis of triazines

  8. Performance analysis of small capacity liquid nitrogen generator based on Joule-Thomson refrigerator coupled with air separation membrane

    NASA Astrophysics Data System (ADS)

    Piotrowska-Hajnus, Agnieszka; Chorowski, Maciej

    2012-06-01

    Joule - Thomson small capacity refrigerators supplied with gas mixture are studied theoretically and experimentally for a variety of applications. They can be especially promising when coupled with membrane air separators. We present liquid nitrogen generation system based on Joule - Thomson cooler joined with air separation membrane. Hollow fiber membrane is used for nitrogen separation from compressed and purified atmospheric air. Joule-Thomson refrigerator operates with a dedicated nitrogen - hydrocarbons mixture and provides a cooling power used for the separated nitrogen liquefaction. Special attention has been paid to a heat exchanger coupling the Joule- Thomson refrigerator with the membrane air separator. This paper describes the system design, the procedure of its working parameters optimization and tests results.

  9. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    SciTech Connect

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  10. A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations

    SciTech Connect

    Way, J Douglas

    2011-01-21

    This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

  11. Microcontact Printing of Thiol-Functionalized Ionic Liquid Microarrays for "Membrane-less" and "Spill-less" Gas Sensors.

    PubMed

    Gondosiswanto, Richard; Gunawan, Christian A; Hibbert, David B; Harper, Jason B; Zhao, Chuan

    2016-11-16

    Lab-on-a-chip systems have gained significant interest for both chemical synthesis and assays at the micro-to-nanoscale with a unique set of benefits. However, solvent volatility represents one of the major hurdles to the reliability and reproducibility of the lab-on-a-chip devices for large-scale applications. Here we demonstrate a strategy of combining nonvolatile and functionalized ionic liquids with microcontact printing for fabrication of "wall-less" microreactors and microfluidics with high reproducibility and high throughput. A range of thiol-functionalized ionic liquids have been synthesized and used as inks for microcontact printing of ionic liquid microdroplet arrays onto gold chips. The covalent bonds formed between the thiol-functionalized ionic liquids and the gold substrate offer enhanced stability of the ionic liquid microdroplets, compared to conventional nonfunctionalized ionic liquids, and these microdroplets remain stable in a range of nonpolar and polar solvents, including water. We further demonstrate the use of these open ionic liquid microarrays for fabrication of "membrane-less" and "spill-less" gas sensors with enhanced reproducibility and robustness. Ionic-liquid-based microarray and microfluidics fabricated using the described microcontact printing may provide a versatile platform for a diverse number of applications at scale.

  12. Voltammetry of ion transfer across a polarized room-temperature ionic liquid membrane facilitated by valinomycin: theoretical aspects and application.

    PubMed

    Langmaier, Jan; Samec, Zdenek

    2009-08-01

    Cyclic voltammetry is used to investigate the transfer of alkali-metal cations, protons, and ammonium ions facilitated by the complex formation with valinomycin at the interface between an aqueous electrolyte solution and a room-temperature ionic liquid (RTIL) membrane. The membrane is made of a thin (approximately 112 microm) microporous filter impregnated with an RTIL that is composed of tridodecylmethylammonium cations and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anions. An extension of the existing theory of voltammetry of ion transfer across polarized liquid membranes makes it possible to evaluate the standard ion-transfer potentials for the hydrophilic cations studied, as well as the stability constants (K(i)) of their 1:1 complexes with valinomycin, as log K(i) = 9.0 (H(+)), 11.1 (Li(+)), 12.8 (Na(+)), 17.2 (K(+)), 15.7 (Rb(+)), 15.1 (Cs(+)), and 14.7 (NH(4)(+)). These data point to the remarkably enhanced stability of the valinomycin complexes within RTIL, and to the enhanced selectivity of valinomycin for K(+) over all other univalent ions studied, compared to the conventional K(+) ion-selective liquid-membrane electrodes. Selective complex formation allows one to resolve voltammetric responses of K(+) and Na(+) in the presence of an excess of Mg(2+) or Ca(2+), which is demonstrated by determination of K(+) and Na(+) in the table and tap water samples.

  13. Operation of a breadboard liquid-sorbent/membrane-contactor system for removing carbon dioxide and water vapor from air

    NASA Technical Reports Server (NTRS)

    Mccray, Scott B.; Ray, Rod; Newbold, David D.; Millard, Douglas L.; Friesen, Dwayne T.; Foerg, Sandra

    1992-01-01

    Processes to remove and recover carbon dioxide (CO2) and water vapor from air are essential for successful long-duration space missions. This paper presents results of a developmental program focused on the use of a liquid-sorbent/membrane-contactor (LSMC) system for removal of CO2 and water vapor from air. In this system, air from the spacecraft cabin atmosphere is circulated through one side of a hollow-fiber membrane contactor. On the other side of the membrane contactor is flowed a liquid sorbent, which absorbs the CO2 and water vapor from the feed air. The liquid sorbent is then heated to desorb the CO2 and water vapor. The CO2 is subsequently removed from the system as a concentrated gas stream, whereas the water vapor is condensed, producing a water stream. A breadboard system based on this technology was designed and constructed. Tests showed that the LSMC breadboard system can produce a CO2 stream and a liquid-water stream. Details are presented on the operation of the system, as well as the effects on performance of variations in feed conditions.

  14. Synthesis and characterization of ionic liquid (EMImBF{sub 4})/Li{sup +} - chitosan membranes for ion battery

    SciTech Connect

    Pasaribu, Marvin H. Arcana, I Made Wahyuningrum, Deana

    2015-09-30

    Lithium ion battery has been currently developed and produced because it has a longer life time, high energycapacity, and the efficient use of lithium ion battery that is suitable for storing electrical energy. However, this battery has some drawbacks such as use liquid electrolytes that are prone to leakage and flammability during the battery charging process in high temperature. In this study, an ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) containing Li{sup +} ions was synthesized and combined with chitosan polymer host as a polymer electrolyte membrane for lithium-ion batteries to solve this problems. This ionic liquid was obtained from the anion metathesis reaction between EMImBr and LiBF4 salt, while EMImBr was synthesized from the reaction between 1-methylimidazole and ethyl bromide utilizing Microwave Assisted Organic Synthesis (MAOS) method. The ionic liquid obtained was characterized by microstructure analysis with using NMR and FTIR spectroscopy. The polymer electrolyte membrane was characterized by analysis functional groups (FTIR), ionic conductivity (EIS), and surface morphology (SEM). The analysis results of ion conductivity by the EIS method showed the increase the ionic conductivity value of membranes from 1.30 × 10{sup −2} S cm{sup −1} for chitosan to 1.30 × 10{sup −2} S cm{sup −1} for chitosan with EMImBF4/Li{sup +}, and this result was supported by analysis the surface morphology (SEM)

  15. A comparative study of solid and liquid inner contact benzalkonium chloride ion-selective electrode membranes.

    PubMed

    Abu Shawish, Hazem M; Khedr, Abdalla M; Abed-Almonem, Khalid I; Gaber, M

    2012-11-15

    A comparative study was made between two designs of benzalkonium ion (Bz)-selective electrodes: a silver-coated (solid contact) called electrode A and a PVC membrane (liquid inner contact) called electrode B based on benzalkonium-phosphomolybdate (Bz-PM) as ion-exchanger complex. Electrode A has a linear dynamic range from 2.0×10(-8) to 1.0×10(-2) mol L(-1), with a Nernstian slope of 60±0.3 mV/decade and a detection limit of 2.0×10(-8) mol L(-1). Electrode B shows linearity over the concentration range from 2.0×10(-7) to 1.0×10(-2) mol L(-1), with a Nernstian slope of 55±1.2 mV/decade and a limit of detection of 1.5×10(-7) mol L(-1). Electrode A showed better performance than electrode B. The detection limit of benzalkonium chloride (BzCl) was effectively improved by a solid contact ion-selective electrode (SC-ISE), rather than the traditional liquid inner contact electrode that gives lower detection limits because of diminished ion fluxes. The present electrodes show clear discrimination of BzCl from several inorganic, organic ions, sugars and some common drug excipients. The sensors were applied efficiently for determination of BzCl in its pharmaceutical preparations (eye, ear and nasal drops) using standard addition and the calibration curve methods.

  16. Liquid Desiccant in Air Conditioners: Nano-Engineered Porous Hollow Fiber Membrane-Based Air Conditioning System

    SciTech Connect

    2010-09-02

    BEETIT Project: UTRC is developing an air conditioning system that is optimized for use in warm and humid climates. UTRC’s air conditioning system integrates a liquid drying agent or desiccant and a traditional vapor compression system found in 90% of air conditioners. The drying agent reduces the humidity in the air before it is cooled, using less energy. The technology uses a membrane as a barrier between the air and the liquid salt stream allowing only water vapor to pass through and not the salt molecules. This solves an inherent problem with traditional liquid desiccant systems—carryover of the liquid drying agent into the conditioned air stream—which eliminates corrosion and health issues

  17. Effect of magnetized extender on sperm membrane integrity and development of oocytes in vitro fertilized with liquid storage boar semen.

    PubMed

    Lee, Sang-Hee; Park, Choon-Keun

    2015-03-01

    The objective of this study was to evaluate the effect of a magnetized extender on sperm membrane damage and development of oocytes in vitro fertilized with liquid storage boar semen. Before semen dilution, extender was flowed through a neodymium magnet (0, 2000, 4000 and 6000G) for 5min and collected semen was preserved for 168h at 18°C. In results, plasma membrane integrity with live sperm was significantly higher in semen treated with extenders magnetized at 4000G than sperm treated with extenders magnetized at 0G during semen preservation for 120-168h (p<0.05). In addition, acrosomal membrane damage was significantly lower in semen treated with extenders magnetized at 4000 and 6000G compared to 0 and 2000G during semen preservation for 168h (p<0.05). And mitochondrial membrane damage with all sperm was significantly lower in semen treated with extenders magnetized at 2000G than other groups during semen preservation for 168h. The ability of semen to achieve successful in vitro fertilization was also not significantly different among the groups during preservation. However, when the semen was preserved for 168h, the blastocyst formation rates were significantly higher at 6000G compared to 0 and 2000G (p<0.05). In conclusion, these results suggest that highly magnetized semen extender could protect the sperm membrane from damage, and improve the ability of rates of in vitro blastocyst development and magnetized semen diluter is beneficial for long liquid preservation of boar semen.

  18. Design of Phosphonated Imidazolium-Based Ionic Liquids Grafted on γ-Alumina: Potential Model for Hybrid Membranes

    PubMed Central

    Pizzoccaro, Marie-Alix; Drobek, Martin; Petit, Eddy; Guerrero, Gilles; Hesemann, Peter; Julbe, Anne

    2016-01-01

    Imidazolium bromide-based ionic liquids bearing phosphonyl groups on the cationic part were synthesized and grafted on γ-alumina (γ-Al2O3) powders. These powders were prepared as companion samples of conventional mesoporous γ-alumina membranes, in order to favor a possible transfer of the results to supported membrane materials, which could be used for CO2 separation applications. Effective grafting was demonstrated using energy dispersive X-ray spectrometry (EDX), N2 adsorption measurements, fourier transform infrared spectroscopy (FTIR), and special attention was paid to 31P and 13C solid state nuclear magnetic resonance spectroscopy (NMR). PMID:27472321

  19. Determination of oxytetracycline in milk samples by polymer inclusion membrane separation coupled to high performance liquid chromatography.

    PubMed

    Pérez-Silva, Irma; Rodríguez, José A; Ramírez-Silva, Ma Teresa; Páez-Hernández, Ma Elena

    2012-03-09

    The determination of oxytetracycline in milk samples using a polymer inclusion membrane concept with high performance liquid chromatography (HPLC) was studied. The membranes developed are composed by cellulose acetate as polymer base, Cyanex 923 as carrier and o-nitrophenyl octyl ether as plasticizer. In the optimal conditions, the method exhibits good linearity in the range 0.03-0.20 mg L(-1) with a limit of detection and quantification of 8.2 and 27.3 μg L(-1) respectively. The method was successfully applied to the analysis of milk samples with high selectivity.

  20. Design of Phosphonated Imidazolium-Based Ionic Liquids Grafted on γ-Alumina: Potential Model for Hybrid Membranes.

    PubMed

    Pizzoccaro, Marie-Alix; Drobek, Martin; Petit, Eddy; Guerrero, Gilles; Hesemann, Peter; Julbe, Anne

    2016-07-27

    Imidazolium bromide-based ionic liquids bearing phosphonyl groups on the cationic part were synthesized and grafted on γ-alumina (γ-Al₂O₃) powders. These powders were prepared as companion samples of conventional mesoporous γ-alumina membranes, in order to favor a possible transfer of the results to supported membrane materials, which could be used for CO₂ separation applications. Effective grafting was demonstrated using energy dispersive X-ray spectrometry (EDX), N₂ adsorption measurements, fourier transform infrared spectroscopy (FTIR), and special attention was paid to (31)P and (13)C solid state nuclear magnetic resonance spectroscopy (NMR).

  1. Applicability of a liquid membrane in enrichment and determination of nickel traces from natural waters.

    PubMed

    Domínguez-Lledó, F C; Galindo-Riaño, María D; Díaz-López, I C; García-Vargas, M; Granado-Castro, M D

    2007-09-01

    In this work, a bulk liquid membrane method has been applied for Ni enrichment and separation from natural waters. The carrier-mediated transport was accomplished by pyridine-2-acetaldehyde benzoylhydrazone dissolved in toluene as a complexing agent. The preconcentration was achieved through pH control of source and receiving solutions via a counterflow of protons. The main variables were optimized by using a modified simplex technique. High transport efficiencies (101.2 +/- 1.8-99.7 +/- 4.2%) were provided by the carrier for nickel ions in a receiving phase of 0.31 mol L(-1) nitric acid after 9-13 h depending on sample salinity. The precision of the method was 2.05% (without a saline matrix) and 4.04% (with 40 g L(-1) NaCl) at the 95% confidence level and the detection limit of the blank was 0.015 mug L(-1) Ni for detection by atomic absorption spectroscopy. The applicability of the method was tested on certified reference and real water samples with successful results, even for saline samples. The relative errors were -0.60% for certified reference materials and ranged from -0.39 to 2.90% and from 0.3 to 11.05% for real samples, obtained by comparison of inductively coupled plasma mass spectrometry and adsorptive cathodic stripping voltammetry measurements, respectively.

  2. Selective transport of copper(II) ions across a liquid membrane mediated by Piroxicam.

    PubMed

    Sadeghi, Susan; Mohammadzadeh, Darush; Imampur, Jalal Shakhs

    2005-09-01

    Piroxicam was found to be a highly selective carrier for uphill transport of Cu2+ ions through a chloroform liquid membrane. The transport occurs via a counterflow of protons from the receiving phase to the source phase. The effects of several parameters on the transport of Cu2+ ions, such as the carrier concentration, pH of the source phase, composition of the receiving phase, and duration are described. A high transport efficiency (98+/-2%) was provided by the carrier for Cu2+ ions in a receiving phase of 0.01 mol l(-1) sulfuric acid after 4 h. Different metal ion transport experiments showed that Cu2+ ions were selectively transported over other ions, such as Co2+, Ni2+, Cd2+, Pb2+, Zn2+, UO2(2+) and ZrO2(2+) . In the presence of fluoride ions (used as a suitable masking agent in the source phase), the interfering effects of UO2(2+) and ZrO2(2+) ions were eliminated. The applicability of the method was tested on a real sample, and the results obtained show that it is potentially useful for solvent extraction of copper.

  3. DEVELOPMENT AND SELECTION OF IONIC LIQUID ELECTROLYTES FOR HYDROXIDE CONDUCTING POLYBENZIMIDAZOLE MEMBRANES IN ALKALINE FUEL CELLS

    SciTech Connect

    Fox, E.

    2012-05-01

    Alkaline fuel cell (AFC) operation is currently limited to specialty applications such as low temperatures and pure HO due to the corrosive nature of the electrolyte and formation of carbonates. AFCs are the cheapest and potentially most efficient (approaching 70%) fuel cells. The fact that non-Pt catalysts can be used, makes them an ideal low cost alternative for power production. The anode and cathode are separated by and solid electrolyte or alkaline porous media saturated with KOH. However, CO from the atmosphere or fuel feed severely poisons the electrolyte by forming insoluble carbonates. The corrosivity of KOH (electrolyte) limits operating temperatures to no more than 80°C. This chapter examines the development of ionic liquids electrolytes that are less corrosive, have higher operating temperatures, do not chemically bond to CO and enable alternative fuels. Work is detailed on the IL selection and characterization as well as casting methods within the polybenzimidazole based solid membrane. This approach is novel as it targets the root of the problem (the electrolyte) unlike other current work in alkaline fuel cells which focus on making the fuel cell components more durable.

  4. Alkaline stability of quaternary ammonium cations for alkaline fuel cell membranes and ionic liquids.

    PubMed

    Marino, M G; Kreuer, K D

    2015-02-01

    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.

  5. Optimization of cyanide extraction from wastewater using emulsion liquid membrane system by response surface methodology.

    PubMed

    Xue, Juan Qin; Liu, Ni Na; Li, Guo Ping; Dang, Long Tao

    To solve the disposal problem of cyanide wastewater, removal of cyanide from wastewater using a water-in-oil emulsion type of emulsion liquid membrane (ELM) was studied in this work. Specifically, the effects of surfactant Span-80, carrier trioctylamine (TOA), stripping agent NaOH solution and the emulsion-to-external-phase-volume ratio on removal of cyanide were investigated. Removal of total cyanide was determined using the silver nitrate titration method. Regression analysis and optimization of the conditions were conducted using the Design-Expert software and response surface methodology (RSM). The actual cyanide removals and the removals predicted using RSM analysis were in close agreement, and the optimal conditions were determined to be as follows: the volume fraction of Span-80, 4% (v/v); the volume fraction of TOA, 4% (v/v); the concentration of NaOH, 1% (w/v); and the emulsion-to-external-phase volume ratio, 1:7. Under the optimum conditions, the removal of total cyanide was 95.07%, and the RSM predicted removal was 94.90%, with a small exception. The treatment of cyanide wastewater using an ELM is an effective technique for application in industry.

  6. Analyte loss due to membrane filter adsorption as determined by high-performance liquid chromatography.

    PubMed

    Carlson, M; Thompson, R D

    2000-02-01

    The phenomenon of membrane filter adsorption in high-performance liquid chromatography (HPLC) is investigated utilizing 16 brands of filters representing 3 polymeric materials: cellulose acetate (CA), nylon, and polyvinylidene difluoride in a variety of diameters (3, 4, 7, 13, and 25 mm). Sixteen compounds commonly encountered in drug preparations are selected as sample analytes and classified as acidic, basic, and neutral in chemical behavior. Six mobile phase/sample solvent mixtures are included: 3 with methanol-water and 3 with acetonitrile-water as major constituents. When using methanol as the mobile phase organic component, CA, nylon, and polyvinylidene difluoride (PVDF) filters exhibit negligible to moderate adsorption levels with regard to the neutral and basic drug compounds. The acidic drug test compounds are adsorbed by 50% of all 3 filter materials tested in methanol-water. In acetonitrile, neutral compounds are affected by 31.4%, basic compounds are affected by 47.0%, and acidic compounds are affected by 53.6% of the nylon and PVDF filters. CA is incompatible with acetonitrile and is excluded from the study with this solvent.

  7. Recovery of kraft lignin from pulping wastewater via emulsion liquid membrane process.

    PubMed

    Ooi, Zing-Yi; Harruddin, Norlisa; Othman, Norasikin

    2015-01-01

    Kraft lignin (KL) is a renewable source of many valuable intermediate biochemical products currently derived from petroleum. An excessive of lignin comes from pulping wastewater caused an adverse pollution problems hence affecting human and aquatic life. A comprehensive study pertaining to emulsion liquid membrane (ELM) extraction of lignin from pulping wastewater was presented. ELM formulation contains Aliquat 336 as carrier, kerosene as diluent, sodium bicarbonate (NaHCO3 ) as stripping agent and Span 80 as surfactant. The emulsion stability was investigated at different surfactant concentrations, homogenizer speed and emulsification time. Modifier (2-ethyl-1-hexanol) was added to avoid segregation of third phase while improving the emulsion stability. At optimum conditions, 95% and 56% of lignin were extracted and recovered, respectively at 10 min of extraction time, 0.007 M of Aliquat 336, 0.1 M of NaHCO3 and 1:5 of treat ratio. Additional of modifier was contributed to highest recovery up to 98%. The ELM process was found to be equally feasible and quite effective in the recovery of KL from real pulping wastewater. Therefore, ELM process provides a promising alternative technology to recover KL from pulping wastewater while solving the environmental problems simultaneously.

  8. Engineering development of ceramic membrane reactor system for converting natural gas to hydrogen and synthesis gas for liquid transportation fuels

    SciTech Connect

    1998-07-01

    The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through June 1998.

  9. Synthesis and performance of novel anion exchange membranes based on imidazolium ionic liquids for alkaline fuel cell applications

    NASA Astrophysics Data System (ADS)

    Fang, Jun; Lyu, Ming; Wang, Xin; Wu, Yongbin; Zhao, Jinbao

    2015-06-01

    Novel anion exchange membranes (AEMs) based on two types of imidazolium ionic liquids, 1-vinyl-3-methylimidazolium iodide [VMI]I and 1-vinyl-3-butylimidazolium bromide [VBI]Br, have been synthesized by copolymerization. The obtained membranes are characterized in terms of water uptake, ion exchange capacity (IEC), ionic conductivity as well as thermal and chemical stability. The conductivity reaches 0.0226 Scm-1 at 30 °C. All the membranes show excellent thermostability. The membranes are stable in 10 mol L-1 NaOH solution at 60 °C for 120 h without obvious changes in ion conductivity. Fuel cell performance using the resulting membrane has been investigated. The open circuit voltage (OCV) of the H2/O2 fuel cell is 1.07 V. A peek power density of 116 mW cm-2 is obtained at a current density of 230 mA cm-2 at 60 °C. The results demonstrate the brilliant prospect of the developed membranes for alkaline fuel cell applications.

  10. High temperature ceramic membrane reactors for coal liquid upgrading. Quarterly report No. 10, December 21, 1991--March 20, 1992

    SciTech Connect

    Tsotsis, T.T.

    1992-07-01

    In this project we will study a novel process concept, i.e., the use of ceramic membrane reactors in upgrading of coal model compounds and coal derived liquids. In general terms, the USC research team is responsible for constructing and operating the membrane reactor apparatus and for testing various inorganic membranes for the upgrading of coal derived asphaltenes and coal model compounds. The USC effort will involve the principal investigator of this project and two graduate research assistants. The ALCOA team is responsible for the preparation of the inorganic membranes, for construction and testing of the ceramic membrane modules, and for measurement of their transport properties. The ALCOA research effort will involve Dr. Paul K. T. Liu, who is the project manager of the ALCOA research team, an engineer and a technician. UNOCAL`s contribution will be limited to overall technical assistance in catalyst preparation and the operation of the laboratory upgrading membrane reactor and for analytical back-up and expertise in oil analysis and materials characterization. UNOCAL is a no-cost contractor but will be involved in all aspects of the project, as deemed appropriate.

  11. Membrane-assisted liquid-liquid extraction coupled with gas chromatography-mass spectrometry for determination of selected polycyclic musk compounds and drugs in water samples.

    PubMed

    Einsle, T; Paschke, H; Bruns, K; Schrader, S; Popp, P; Moeder, M

    2006-08-18

    Selected polycyclic musk compounds and drugs were extracted from water samples by membrane-assisted micro liquid-liquid extraction. The two-phase extraction system consisted of polyethylene membrane bags filled with an organic solvent. Chloroform proved to be most suited as acceptor phase to extract caffeine, Galaxolide, Tonalide, phenazone and carbamazepine from aqueous samples. The compounds were enriched from 50 mL sample into a volume of 500 microL of chloroform. Gas chromatography-mass spectrometry (GC-MS) was applied for analysis. The extraction procedure was optimised in regard to membrane material, extraction time and temperature. The evaluation of the entire analysis protocol found limits of detection that ranged from 20 to 200 ng/L. The linear range of calibration covered one magnitude with standard deviations between 4 and 12%. Method comparison with standard analysis techniques such as solid-phase extraction (SPE) combined with GC-MS as well as LC-MS-MS confirmed this method as an easy and reliable protocol, even for the monitoring of matrix-loaded wastewater. The analysis of real samples established the feasibility of the technique.

  12. New types of Brönsted acid-base ionic liquids-based membranes for applications in PEMFCs.

    PubMed

    Fernicola, Alessandra; Panero, Stefania; Scrosati, Bruno; Tamada, Masahiro; Ohno, Hiroyuki

    2007-05-14

    A series of ionic liquids (ILs) are prepared by neutralizing tertiary amines with N,N-bis(trifluoromethanesulfonyl)imide (HTFSI). As demonstrated by thermal and electrochemical characterizations, these ILs have very good temperature stability and a high ionic conductivity, that is, of the order of 10(-2) S cm-1. By incorporating these ILs into a poly(vinylidenfluoride-co-hexafluoropropylene) polymer matrix, membranes with a high melting temperature, high decomposition point and with an ionic conductivity of about 10(-2) S cm-1 at 140 degrees C, are obtained. These IL-based, proton-conducting membranes are proposed as new polymer electrolytes for high-temperature polymer electrolyte membrane fuel cells (PEMFCs).

  13. Analysis and quantification of parabens in cosmetic products by utilizing hollow fibre-supported liquid membrane and high performance liquid chromatography with ultraviolet detection.

    PubMed

    Msagati, T A M; Barri, T; Larsson, N; Jönsson, J A

    2008-08-01

    A simple and direct method based on hollow fibre-supported liquid membrane (HFSLM) extraction and liquid chromatography equipped with a UV detector was developed for analysis and quantification of parabens in cosmetic products. The parabens analysed included methyl, ethyl, propyl, isobutyl and butyl paraben. The HFSLM extraction was carried out by employing di-n-hexyl ether as organic liquid that was immobilized in the hollow fibre membrane. The HFSLM extraction is simple, cheap, minimizes the use of solvents and uses disposable material. In an investigation of 11 paraben-containing cosmetic products, the levels of parabens (sum of all parabens in a product) ranged from 0.43% to 0.79% (w/w) for skin care products, 0.07-0.44% for hair fixing gels and 0.30-0.52% for soap solutions. The levels of individual parabens in individual cosmetic products ranged between 0.03% and 0.42% w/w for skin care products, 0.07% and 0.26% w/w for hair fixing gels and between 0.11% and 0.34% w/w for soap solutions. Parabens were found in the highest concentrations in skin care products followed by soap solutions and the least amounts were found in hair fixing gels. Of the paraben-containing products tested, all of them contained methyl paraben and about 90% contained propyl paraben in addition to methyl paraben. One product contained all the parabens analysed.

  14. Effects of membrane type and liquid/liquid phase boundary on in vitro release of ketoprofen from gel formulations.

    PubMed

    Gallagher, Simon J; Trottet, Lionel; Carter, Timothy P; Heard, Charles M

    2003-07-01

    The aim of this study was to test the hypothesis that the most appropriate model for studying the diffusional release of an active from a topical formulation is one in which the membrane offers minimal resistance to release and involves a receptor phase that presents the least possible interfacial discontinuity. Using ketoprofen as the active, a series of simple gels were prepared consisting of PEG400 thickened with Cabosil M5. Using Franz-type diffusion cells, three different types of membrane (two porous and one non-porous) were compared, as were receptor phases of PEG400 (component of formulation) and PBS. Of the membranes tested only 0.2 microm nylon provided consistent first order kinetics for a range of gel consistencies, indicating negligible influence of the membrane. The non-porous silicone membrane did not show first order kinetic profile confirming the diffusional nature of such a membrane. From the non-thickened formulations, diffusional release into a receptor phase of PEG400 was some 3x that into PBS, whereas from the formulation thickened with 5% Cabosil M5, diffusional release into a receptor phase of PEG400 was 6x lower than that into PBS. Diffusional release into PBS did not follow first order kinetics while diffusion into PEG400 did, suggesting that the existence of a discontinuity affected the release process. Although the importance of zero-resistance membranes is of perhaps obvious importance, it is often not stated in the literature. The existence of phase/hydrodynamic boundaries in release studies can be a source of significant inaccuracy.

  15. Three-dimensional dynamic structure of the liquid-ordered domain in lipid membranes as examined by pulse-EPR oxygen probing.

    PubMed

    Subczynski, Witold K; Wisniewska, Anna; Hyde, James S; Kusumi, Akihiro

    2007-03-01

    Membranes made of dimyristoylphosphatidylcholine and cholesterol, one of the simplest paradigms for the study of liquid ordered-disordered phase separation, were investigated using a pulse-EPR spin-labeling method in which bimolecular collision of molecular oxygen with the nitroxide spin label is measured. This method allowed discrimination of liquid-ordered, liquid-disordered, and solid-ordered domains because the collision rates (OTP) differ in these domains. Furthermore, the oxygen transport parameter (OTP) profile across the bilayer provides unique information about the three-dimensional dynamic organization of the membrane domains. First, the OTP in the bilayer center in the liquid-ordered domain was comparable to that in the liquid-disordered domain without cholesterol, but the OTP near the membrane surface (up to carbon 9) was substantially smaller in the ordered domain, i.e., the cholesterol-based liquid-ordered domain is ordered only near the membrane surface, still retaining high levels of disorder in the bilayer center. This property may facilitate lateral mobility in ordered domains. Second, in the liquid-disordered domain, the domains with approximately 5 mol % cholesterol exhibited higher OTP than those without cholesterol, everywhere across the membrane. Third, the transmembrane OTP profile in the liquid-ordered domain that contained 50 mol % cholesterol dramatically differed from that which contained 27 mol % cholesterol.

  16. The liquid-ordered phase in sphingomyelincholesterol membranes as detected by the discrimination by oxygen transport (DOT) method.

    PubMed

    Wisniewska, Anna; Subczynski, Witold K

    2008-01-01

    Membranes made from binary mixtures of egg sphingomyelin (ESM) and cholesterol were investigated using conventional and saturation-recovery EPR observations of the 5-doxylstearic acid spin label (5-SASL). The effects of cholesterol on membrane order and the oxygen transport parameter (bimolecular collision rate of molecular oxygen with the nitroxide spin label) were monitored at the depth of the fifth carbon in fluid- and gel-phase ESM membranes. The saturation-recovery EPR discrimination by oxygen transport (DOT) method allowed the discrimination of the liquid-ordered (l(o)), liquid-disordered (l(d)), and solid-ordered (s(o)) phases because the bimolecular collision rates of the molecular oxygen with the nitroxide spin label differ in these phases. Additionally, oxygen collision rates (the oxygen transport parameter) were obtained in coexisting phases without the need for their separation, which provides information about the internal dynamics of each phase. The addition of cholesterol causes a dramatic decrease in the oxygen transport parameter around the nitroxide moiety of 5-SASL in the l(o) phase, which at 50 mol% cholesterol becomes approximately 5 times smaller than in the pure ESM membrane in the l(d) phase, and approximately 2 times smaller than in the pure ESM membrane in the s(o) phase. The overall change in the oxygen transport parameter is as large as approximately 20-fold. Conventional EPR spectra show that 5-SASL is maximally immobilized at the phase boundary between regions with coexisting l(d) and l(o) phases or s(o) and l(o) phases and the region with a single l(o) phase. The obtained results allowed for the construction of a phase diagram for the ESM-cholesterol membrane.

  17. Novel Ceramic-Polymer Composite Membranes for the Separation of Hazardous Liquid Waste

    SciTech Connect

    Yoram Cohen

    2001-12-01

    The present project was conceived to address the need for robust yet selective membranes suitable for operating in harsh ph, solvent, and temperature environments. An important goal of the project was to develop a membrane chemical modification technology that would allow one to tailor-design membranes for targeted separation tasks. The method developed in the present study is based on the process of surface graft polymerization. Using essentially the same base technology of surface modification the research was aimed at demonstrating that improved membranes can be designed for both pervaporation separation and ultrafiltration. In the case of pervaporation, the present study was the first to demonstrate that pervaporation can be achieved with ceramic support membranes modified with an essentially molecular layer of terminally anchored polymer chains. The main advantage of the above approach, relative to other proposed membranes, is that the separating polymer layer is covalently attached to the ceramic support. Therefore, such membranes have a potential use in organic-organic separations where the polymer can swell significantly yet membrane robustness is maintained due to the chemical linkage of the chains to be inorganic support. The above membrane technology was also useful in developing fouling resistant ultrafiltration membranes. The prototype membrane developed in the project was evaluated for the treatment of oil-in-water microemulsions, demonstrating lack of irreversible fouling common with commercial membranes.

  18. Micro-electromembrane extraction across free liquid membranes. Extractions of basic drugs from undiluted biological samples.

    PubMed

    Kubáň, Pavel; Boček, Petr

    2014-04-11

    This contribution describes properties and utilization of free liquid membranes (FLMs) in micro-electromembrane extraction (μ-EME) of analytes from samples with complex matrices. An FLM was formed as a plug of a selected organic solvent, 1-ethyl-2-nitrobenezene (ENB) or 2-nitrophenyloctyl ether, in a narrow bore polymeric tubing and was sandwiched between a plug of aqueous donor and aqueous acceptor solution. The FLM acted as a phase interface that enabled selective transfer of analytes from donor into acceptor solution. Acceptor solution after μ-EME was analysed by capillary electrophoresis (CE). Fundamental characteristics of FLMs were depicted and discussed by presenting experimental data on their performance for various basic operational parameters, such as composition and volume of donor/acceptor solution, applied extraction voltage, thickness of FLM and extraction time. Positively charged basic drugs (nortriptyline, haloperidol and loperamide) and their solutions in water, urine and blood serum served as model samples. It was shown that FLMs may offer fast, efficient and selective pretreatment of crude biological samples providing that basic operational parameters of μ-EME are set properly. At optimised conditions, basic drugs in 1.5μL of a biological sample were transferred across 1.5μL of FLM (ENB) into 1.5μL of acceptor solution in about 5min at an extraction voltage of 100V. Repeatability values of μ-EMEs and CE-UV analyses of the three basic drugs were better than 7.7% for peak areas, recoveries ranged between 19 and 52% and linear relationship was obtained for analytical signal vs. concentration in 1-50mgL(-1) range (r(2) better than 0.996). Limits of detection, defined as 3×S/N, were below 1mgL(-1) for all examined matrices.

  19. Performance Validation and Scaling of a Capillary Membrane Solid-Liquid Separation System

    SciTech Connect

    Rogers, S; Cook, J; Juratovac, J; Goodwillie, J; Burke, T

    2011-10-25

    Algaeventure Systems (AVS) has previously demonstrated an innovative technology for dewatering algae slurries that dramatically reduces energy consumption by utilizing surface physics and capillary action. Funded by a $6M ARPA-E award, transforming the original Harvesting, Dewatering and Drying (HDD) prototype machine into a commercially viable technology has required significant attention to material performance, integration of sensors and control systems, and especially addressing scaling issues that would allow processing extreme volumes of algal cultivation media/slurry. Decoupling the harvesting, dewatering and drying processes, and addressing the rate limiting steps for each of the individual steps has allowed for the development individual technologies that may be tailored to the specific needs of various cultivation systems. The primary performance metric used by AVS to assess the economic viability of its Solid-Liquid Separation (SLS) dewatering technology is algae mass production rate as a function of power consumption (cost), cake solids/moisture content, and solids capture efficiency. An associated secondary performance metric is algae mass loading rate which is dependent on hydraulic loading rate, area-specific hydraulic processing capacity (gpm/in2), filter:capillary belt contact area, and influent algae concentration. The system is capable of dewatering 4 g/L (0.4%) algae streams to solids concentrations up to 30% with capture efficiencies of 80+%, however mass production is highly dependent on average cell size (which determines filter mesh size and percent open area). This paper will present data detailing the scaling efforts to date. Characterization and performance data for novel membranes, as well as optimization of off-the-shelf filter materials will be examined. Third party validation from Ohio University on performance and operating cost, as well as design modification suggestions will be discussed. Extrapolation of current productivities

  20. Separation of alkali, alkaline earth and rare earth cations by liquid membranes containing macrocyclic carriers. Fourth progress report, 1 November 1981-31 July 1982

    SciTech Connect

    Christensen, J J; Izatt, R M

    1982-07-31

    The H/sub 2/O-CHCl/sub 3/-H/sub 2/O liquid membrane system was characterized with respect to the effect on cation (K/sup +/) transport rate of salt concentration and anion type. A bulk liquid membrane cell was used. A mathematical model for cation flux is being developed for several cations, several macrocycles, and mixtures of two or three cations. Eu/sup 3 +/ was not transported by 18-crown-6, but its reduced from Eu/sup 2 +/ was. Cation transport properties of calixarenes are also being investigated. Emulsion membrane systems were studied as a way of increasing the cation transport. Pb/sup 2 +/ was found to be transported by dicyclohexano-18-crown-6 through the liquid membrane. Transport rates of metal cation nitrates were measured in a water-toluene-water emulsion membrane system. 14 figures, 7 tables. (DLC)

  1. Proteomic characterization of integral membrane proteins using thermostatted liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Moore, Sarah M; Wu, Christine C

    2012-01-01

    Due to the hydrophobicity and localization of integral membrane proteins, they are difficult to study using conventional biochemical methods that are compatible with proteomic analyses. This chapter describes the coupling of multiple crucial steps that lead to the optimized shotgun proteomic analysis of integral membrane proteins while maintaining empirical topology information. Namely, a membrane shaving method is utilized to separate protease accessible peptides from membrane embedded peptides and elevated temperatures during chromatographic separation is utilized to augment the recovery of hydrophobic peptides for in-line analysis using tandem mass spectrometry. This combination of steps facilitates increased identification of membrane proteins while also maintaining information regarding protein topology.

  2. Exploiting the Phenomenon of Liquid-Liquid Phase Separation for Enhanced and Sustained Membrane Transport of a Poorly Water-Soluble Drug.

    PubMed

    Indulkar, Anura S; Gao, Yi; Raina, Shweta A; Zhang, Geoff G Z; Taylor, Lynne S

    2016-06-06

    Recent studies on aqueous supersaturated lipophilic drug solutions prepared by methods including antisolvent addition, pH swing, or dissolution of amorphous solid dispersions (ASDs) have demonstrated that when crystallization is slow, these systems undergo liquid-liquid phase separation (LLPS) when the concentration of the drug in the medium exceeds its amorphous solubility. Following LLPS, a metastable equilibrium is formed where the concentration of drug in the continuous phase corresponds to the amorphous solubility while the dispersed phase is composed of a nanosized drug-rich phase. It has been reasoned that the drug-rich phase may act as a reservoir, enabling the rate of passive transport of the drug across a membrane to be maintained at the maximum value for an extended period of time. Herein, using clotrimazole as a model drug, and a flow-through diffusion cell, the reservoir effect is demonstrated. Supersaturated clotrimazole solutions at concentrations below the amorphous solubility show a linear relationship between the maximum flux and the initial concentration. Once the concentration exceeds the amorphous solubility, the maximum flux achieved reaches a plateau. However, the duration for which the high flux persists was found to be highly dependent on the number of drug-rich nanodroplets present in the donor compartment. Macroscopic amorphous particles of clotrimazole did not lead to the same reservoir effect observed with the nanodroplets formed through the process of LLPS. A first-principles mathematical model was developed which was able to fit the experimental receiver concentration-time profiles for concentration regimes both below and above amorphous solubility, providing support for the contention that the nanodroplet phase does not directly diffuse across the membrane but, instead, rapidly replenishes the drug in the aqueous phase that has been removed by transport across the membrane. This study provides important insight into the properties of

  3. Electro membrane isolation of nerve agent degradation products across a supported liquid membrane followed by capillary electrophoresis with contactless conductivity detection.

    PubMed

    Xu, Li; Hauser, Peter C; Lee, Hian Kee

    2008-12-19

    In the present study, electro membrane isolation (EMI) of four nerve agent degradation products has been successfully explored. In the procedure, a polypropylene sheet membrane folded into an envelope with an open end with its wall pores impregnated with 1-octanol was employed as the artificial supported liquid membrane (SLM). The envelope containing the extractant or aqueous acceptor phase (at pH 6.8) was immersed in the sample or donor phase (also aqueous at a pH of 6.8) for extraction. This ensured that the target analytes were fully ionized. A voltage was then applied, with the negative electrode placed in the donor phase with agitation, and the positive electrode in the acceptor phase. The ionized analytes were thus driven to migrate from the donor phase across the SLM to the acceptor phase. The factors influential to extraction: type of organic solvent, voltage, agitation speed, extraction time, pH of the donor and acceptor phase and concentration of humic acids were investigated in detail. After extraction, the acceptor phase was collected and directly injected for capillary electrophoretic (CE) analysis. Combined with capacitively coupled contactless conductivity detection (C(4)D), the direct detection of these compounds could be achieved. Moreover, large-volume sample injection was employed to further enhance the sensitivity of this method. Limits of detection (LODs) as low as ng/mL were reached for the studied analytes, with overall LOD enhancements of four orders of magnitude.

  4. Survival and growth of Salmonella Enteritidis in membrane processed liquid egg white with pH, temperature and storage conditions as controlling factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was undertaken to determine the effect of variation in solution pH and process temperature on the removal and regrowth of Salmonella Enteritidis in liquid egg white (LEW) by microfiltration (MF) membrane process. Influence of various storage conditions on growth of Salmonella in membrane sep...

  5. Influence of pH, temperature and storage condition on survival and growth of Salmonella Enteritidis in membrane processed liquid egg white

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Study was conducted to establish the effects of variations in liquid egg pH and membrane processing temperature on the removal and growth of Salmonella Enteritidis in liquid egg white (LEW) filtered by microfiltration (MF) process. Storage condition variations influence on growth of Salmonella in th...

  6. Novel Ceramic-Polymer Composite Membranes for the Separation of Liquid Waste

    SciTech Connect

    Cohen, Yoram

    2000-06-01

    There is a growing need in the areas of hazardous waste treatment, remediation and pollution prevention for new processes capable of selectively separating and removing target organic species from aqueous steams. Membrane separation processes are especially suited for solute removal from dilute solutions. They have the additional advantage of requiring less energy relative to conventional separation technologies (e.g., distillation, extraction and even adsorption processes). The major difficulty with current membranes is the poor longevity of polymeric membranes under harsh conditions (high temperature, harsh solvents and pH conditions) and the lack of selectivity of ceramic membranes. In our previous work (1996 EMSP project), a first generation of novel polymer-ceramic (PolyCer) composite membranes were developed with the goal of overcoming the above difficulties. The proposed PolyCer membranes are fabricated by a surface-graft polymerization process resulting in a molecular layer of polymer chains which are terminally and covalently anchored to the porous membrane support. The polymer imparts the desired membrane selectivity while the ceramic support provides structural integrity. The PolyCer membrane retain its structural integrity and performance even when the polymer phase is exposed to harsh solvent conditions since the polymer chains are covalently bonded to the ceramic support surface. To date, prototype PolyCer membranes were developed for two different membrane separation processes: (a) pervaporation removal of organics from aqueous systems; and (b) ultrafiltration of oil-in-water emulsions. Pervaporation PolyCer membranes were demonstrated for removal of selected organics (TCE, chloroform and MTBE) from water with permeate enrichment factors as high as 300. While the above results have been extremely encouraging, higher enrichment factors (>1000) should be sought for field applications. The above improvement is feasible by increasing the length and

  7. Grafting of cellulose acetate with ionic liquids for biofuel purification by a membrane process: Influence of the cation.

    PubMed

    Hassan Hassan Abdellatif, Faten; Babin, Jérôme; Arnal-Herault, Carole; David, Laurent; Jonquieres, Anne

    2016-08-20

    A new strategy was developed for grafting ionic liquids (ILs) onto cellulose acetate in order to avoid IL extraction and improve its performance for ethyl tert-butyl ether (ETBE) biofuel purification by the pervaporation membrane process. This work extended the scope of IL-containing membranes to the challenging separation of organic liquid mixtures, in which these ILs were soluble. The ILs contained the same bromide anion and different cations with increasing polar feature. The membrane properties were strongly improved by IL grafting. Their analysis in terms of structure-property relationships revealed the influence of the IL content, chemical structure and chemical physical parameters α, β, π* in the Kamlet-Taft polarity scale. The ammonium IL led to the best normalized flux of 0.182kg/m(2)h for a reference thickness of 5μm, a permeate ethanol content of 100% and an outstanding infinite separation factor for the azeotropic mixture EtOH/ETBE at 50°C.

  8. Increased productivity of Clostridium acetobutylicum fermentation of acetone, butanol, and ethanol by pervaporation through supported ionic liquid membrane.

    PubMed

    Izák, Pavel; Schwarz, Katrin; Ruth, Wolfgang; Bahl, Hubert; Kragl, Udo

    2008-03-01

    Pervaporation proved to be one of the best methods to remove solvents out of a solvent producing Clostridium acetobutylicum culture. By using an ionic liquid (IL)-polydimethylsiloxane (PDMS) ultrafiltration membrane (pore size 60 nm), we could guarantee high stability and selectivity during all measurements carried out at 37 degrees C. Overall solvent productivity of fermentation connected with continuous product removal by pervaporation was 2.34 g l(-1) h(-1). The supported ionic liquid membrane (SILM) was impregnated with 15 wt% of a novel ionic liquid (tetrapropylammonium tetracyano-borate) and 85 wt% of polydimethylsiloxane. Pervaporation, accomplished with the optimized SILM, led to stable and efficient removal of the solvents butan-1-ol and acetone out of a C. acetobutylicum culture. By pervaporation through SILM, we removed more butan-1-ol than C. acetobutylicum was able to produce. Therefore, we added an extra dose of butan-1-ol to run fermentation on limiting values where the bacteria would still be able to survive its lethal concentration (15.82 g/l). After pervaporation was switched off, the bacteria died from high concentration of butan-1-ol, which they produced.

  9. A hybrid liquid-phase precipitation (LPP) process in conjunction with membrane distillation (MD) for the treatment of the INEEL sodium-bearing liquid waste.

    PubMed

    Bader, M S H

    2005-05-20

    A novel hybrid system combining liquid-phase precipitation (LPP) and membrane distillation (MD) is integrated for the treatment of the INEEL sodium-bearing liquid waste. The integrated system provides a "full separation" approach that consists of three main processing stages. The first stage is focused on the separation and recovery of nitric acid from the bulk of the waste stream using vacuum membrane distillation (VMD). In the second stage, polyvalent cations (mainly TRU elements and their fission products except cesium along with aluminum and other toxic metals) are separated from the bulk of monovalent anions and cations (dominantly sodium nitrate) by a front-end LPP. In the third stage, MD is used first to concentrate sodium nitrate to near saturation followed by a rear-end LPP to precipitate and separate sodium nitrate along with the remaining minor species from the bulk of the aqueous phase. The LPP-MD hybrid system uses a small amount of an additive and energy to carry out the treatment, addresses multiple critical species, extracts an economic value from some of waste species, generates minimal waste with suitable disposal paths, and offers rapid deployment. As such, the LPP-MD could be a valuable tool for multiple needs across the DOE complex where no effective or economic alternatives are available.

  10. Hydrogen production by reforming of liquid hydrocarbons in a membrane reactor for portable power generation-Experimental studies

    NASA Astrophysics Data System (ADS)

    Damle, Ashok S.

    One of the most promising technologies for lightweight, compact, portable power generation is proton exchange membrane (PEM) fuel cells. PEM fuel cells, however, require a source of pure hydrogen. Steam reforming of hydrocarbons in an integrated membrane reactor has potential to provide pure hydrogen in a compact system. Continuous separation of product hydrogen from the reforming gas mixture is expected to increase the yield of hydrogen significantly as predicted by model simulations. In the laboratory-scale experimental studies reported here steam reforming of liquid hydrocarbon fuels, butane, methanol and Clearlite ® was conducted to produce pure hydrogen in a single step membrane reformer using commercially available Pd-Ag foil membranes and reforming/WGS catalysts. All of the experimental results demonstrated increase in hydrocarbon conversion due to hydrogen separation when compared with the hydrocarbon conversion without any hydrogen separation. Increase in hydrogen recovery was also shown to result in corresponding increase in hydrocarbon conversion in these studies demonstrating the basic concept. The experiments also provided insight into the effect of individual variables such as pressure, temperature, gas space velocity, and steam to carbon ratio. Steam reforming of butane was found to be limited by reaction kinetics for the experimental conditions used: catalysts used, average gas space velocity, and the reactor characteristics of surface area to volume ratio. Steam reforming of methanol in the presence of only WGS catalyst on the other hand indicated that the membrane reactor performance was limited by membrane permeation, especially at lower temperatures and lower feed pressures due to slower reconstitution of CO and H 2 into methane thus maintaining high hydrogen partial pressures in the reacting gas mixture. The limited amount of data collected with steam reforming of Clearlite ® indicated very good match between theoretical predictions and

  11. Experimental investigation of the permeability and selectivity of supported ionic liquid membranes for CO2/He separation at temperatures up to 125° C

    SciTech Connect

    Ilconich, J.B.; Myers, C.R.; Pennline, H.W.; Luebke, D.R.

    2007-07-01

    Supported liquid membranes have been prepared by impregnation of commercial porous polymer films with the ionic liquid 1-n-hexyl-3- methylimidazolium bis(trifluoromethanesulfonyl)imide. The ionic liquid has been characterized, and the membranes have been tested to determine performance in the selective separation of CO2 from He. Experiments were conducted in a constant pressure system, and pure gas permeability/selectivity data are reported. Membranes prepared with polysulfone supports have been found to be stable to 125 °C. The CO2 permeability of the membranes increases from 744 to 1200 barrer as the temperature increases from 37 to 125 °C. The CO2/He selectivity decreased from 8.7 to 3.1 over the same temperature range.

  12. Simulation studies of the membrane exchange assembly of an all-liquid, proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Byrd, Ethan D.; Miley, George H.

    A model has been designed and constructed for the all-liquid, sodium borohydride/hydrogen peroxide fuel cell under development at the University of Illinois at Urbana-Champaign. The electrochemical behavior, momentum balance, and mass balance effects within the fuel cell are modeled using the Butler-Volmer equations, Darcy's law, and Fick's law, respectively, within a finite element modeling platform. The simulations performed with the model indicate that an optimal physical design of the fuel cell's flow channel land area or current collector exists when considering the pressure differential between channels, and the diffusion layer permeability and conductivity. If properties of the diffusion layer are known, the model is an effective method of improving the fuel cell design in order to achieve higher power density.

  13. Structure-Antibacterial Activity Relationships of Imidazolium-Type Ionic Liquid Monomers, Poly(ionic liquids) and Poly(ionic liquid) Membranes: Effect of Alkyl Chain Length and Cations.

    PubMed

    Zheng, Zhiqiang; Xu, Qiming; Guo, Jiangna; Qin, Jing; Mao, Hailei; Wang, Bin; Yan, Feng

    2016-05-25

    The structure-antibacterial activity relationship between the small molecular compounds and polymers are still elusive. Here, imidazolium-type ionic liquid (IL) monomers and their corresponding poly(ionic liquids) (PILs) and poly(ionic liquid) membranes were synthesized. The effect of chemical structure, including carbon chain length of substitution at the N3 position and charge density of cations (mono- or bis-imidazolium) on the antimicrobial activities against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated by determination of minimum inhibitory concentration (MIC). The antibacterial activities of both ILs and PILs were improved with the increase of the alkyl chain length and higher charge density (bis-cations) of imidazolium cations. Moreover, PILs exhibited lower MIC values relative to the IL monomers. However, the antibacterial activities of PIL membranes showed no correlation to those of their analogous small molecule IL monomers and PILs, which increased with the charge density (bis-cations) while decreasing with the increase of alkyl chain length. The results indicated that antibacterial property studies on small molecules and homopolymers may not provide a solid basis for evaluating that in corresponding polymer membranes.

  14. Investigation of Ion Channel Activities of Gramicidin A in the Presence of Ionic Liquids Using Model Cell Membranes

    PubMed Central

    Ryu, Hyunil; Lee, Hwankyu; Iwata, Seigo; Choi, Sangbaek; Ki Kim, Moon; Kim, Young-Rok; Maruta, Shinsaku; Min Kim, Sun; Jeon, Tae-Joon

    2015-01-01

    Ionic liquids (ILs) are considered to be green solvents because of their non-volatility. Although ILs are relatively safe in the atmospheric environment, they may be toxic in other environments. Our previous research showed that the cytotoxicity of ILs to biological organisms is attributable to interference with cell membranes by IL insertion. However, the effects of ILs on ion channels, which play important roles in cell homeostasis, have not been comprehensively studied to date. In this work, we studied the interactions between ILs and lipid bilayer membranes with gramicidin A ion channels. We used two methods, namely electrical and fluorescence measurements of ions that permeate the membrane. The lifetimes of channels were increased by all the ILs tested in this work via stabilizing the compressed structure of the lipid bilayer and the rate of ion flux through gA channels was decreased by changing the membrane surface charge. The former effect, which increased the rate of ion flux, was dominant at high salt concentrations, whereas the latter, which decreased the rate of ion flux, was dominant at low salt concentrations. The effects of ILs increased with increasing concentration and alkyl chain length. The experimental results were further studied using molecular dynamics simulations. PMID:26189604

  15. Investigation of Ion Channel Activities of Gramicidin A in the Presence of Ionic Liquids Using Model Cell Membranes.

    PubMed

    Ryu, Hyunil; Lee, Hwankyu; Iwata, Seigo; Choi, Sangbaek; Kim, Moon Ki; Kim, Young-Rok; Maruta, Shinsaku; Kim, Sun Min; Jeon, Tae-Joon

    2015-07-20

    Ionic liquids (ILs) are considered to be green solvents because of their non-volatility. Although ILs are relatively safe in the atmospheric environment, they may be toxic in other environments. Our previous research showed that the cytotoxicity of ILs to biological organisms is attributable to interference with cell membranes by IL insertion. However, the effects of ILs on ion channels, which play important roles in cell homeostasis, have not been comprehensively studied to date. In this work, we studied the interactions between ILs and lipid bilayer membranes with gramicidin A ion channels. We used two methods, namely electrical and fluorescence measurements of ions that permeate the membrane. The lifetimes of channels were increased by all the ILs tested in this work via stabilizing the compressed structure of the lipid bilayer and the rate of ion flux through gA channels was decreased by changing the membrane surface charge. The former effect, which increased the rate of ion flux, was dominant at high salt concentrations, whereas the latter, which decreased the rate of ion flux, was dominant at low salt concentrations. The effects of ILs increased with increasing concentration and alkyl chain length. The experimental results were further studied using molecular dynamics simulations.

  16. Reforming of Liquid Hydrocarbons in a Novel Hydrogen-Selective Membrane-Based Fuel Processor

    SciTech Connect

    Shamsuddin Ilias

    2006-03-10

    In this work, asymmetric dense Pd/porous stainless steel composite membranes were fabricated by depositing palladium on the outer surface of the tubular support. The electroless plating method combined with an osmotic pressure field was used to deposit the palladium film. Surface morphology and microstructure of the composite membranes were characterized by SEM and EDX. The SEM and EDX analyses revealed strong adhesion of the plated pure palladium film on the substrate and dense coalescence of the Pd film. Membranes were further characterized by conducting permeability experiments with pure hydrogen, nitrogen, and helium gases at temperatures from 325 to 450 C and transmembrane pressure differences from 5 to 45 psi. The permeation results showed that the fabricated membranes have both high hydrogen permeability and selectivity. For example, the hydrogen permeability for a composite membrane with a 20 {micro}m Pd film was 3.02 x 10{sup -5} moles/m{sup 2}.s.Pa{sup 0.765} at 450 C. Hydrogen/nitrogen selectivity for this composite membrane was 1000 at 450 C with a transmembrane pressure difference of 14.7 psi. Steam reforming of methane is one of the most important chemical processes in hydrogen and syngas production. To investigate the usefulness of palladium-based composite membranes in membrane-reactor configuration for simultaneous production and separation of hydrogen, steam reforming of methane by equilibrium shift was studied. The steam reforming of methane using a packed-bed inert membrane tubular reactor (PBIMTR) was simulated. A two-dimensional pseudo-homogeneous reactor model with parallel flow configuration was developed for steam reforming of methane. The shell volume was taken as the feed and sweep gas was fed to the inside of the membrane tube. Radial diffusion was taken into account for concentration gradient in the radial direction due to hydrogen permeation through the membrane. With appropriate reaction rate expressions, a set of partial differential

  17. Facilitated transport of uranium(VI) across supported liquid membranes containing T2EHDGA as the carrier extractant.

    PubMed

    Panja, S; Mohapatra, P K; Tripathi, S C; Manchanda, V K

    2011-04-15

    Facilitated transport of uranyl ion from nitric acid feed solutions was investigated across PTFE supported liquid membranes using N,N,N',N'-tetra-2-ethylhexyl-3-pentane-diamide (T2EHDGA) in n-dodecane as the carrier extractant containing 30% iso-decanol as the phase modifier. Solvent extraction studies indicated extraction of species of the type, UO(2)(NO(3))(2)·T2EHDGA. The distribution coefficients increased in the presence of NaNO(3) as compared to equivalent concentration of HNO(3) which was exactly the opposite of what was reported for Am(III)-TODGA extraction system. Supported liquid membrane studies indicated about 11h were required for quantitative transport of U(VI) from a feed of 3M HNO(3) using 0.2M T2EHDGA in n-dodecane containing 30% iso-decanol as the carrier extractant. Effect of various parameters such as feed acidity, T2EHDGA concentration, and nature of the strippant on the transport rate was investigated. The transport was found to be diffusion controlled in the membrane phase and the permeability coefficient was calculated to be (3.20 ± 0.13)× 10(-4)cm/s for the feed composition of 3M HNO(3), receiver phase composition of 0.01 M HNO(3) and membrane carrier phase of 0.2M T2EHDGA in n-dodecane containing 30% iso-decanol. The present results may be useful for the separation of U from lean solutions or radioactive wastes considered hazardous due to the presence of alpha-particle emitting radionuclides.

  18. Ionic conductivity of mesoporous block copolymer membranes in liquid electrolyte as a function of copolymer and homopolymer molecular weight

    NASA Astrophysics Data System (ADS)

    Wong, David; Mullin, Scott; Stone, Greg; Battaglia, Vincent; Balsara, Nitash

    2011-03-01

    Mesoporous block copolymer membranes have been synthesized using poly(styrene-block-ethylene-block-polystyrene) (SES). A series of symmetric SES copolymers and PS homopolymers have been studied at different blending fractions. Ionic conductivities of the porous films in a liquid electrolyte, 1.0 M Li PF6 in ethylene carbonate/diethyl carbonate, compare favorably to conventional battery separators and generally increase with internal surface area, as measured by nitrogen adsorption. Characterization of the effects of pore structure and SES morphology on conductivity will be presented. Support from the U.S. Department of Energy Office of Vehicles Technologies (FCVT) under the Batteries for Advanced Transportation Technologies (BATT) Program.

  19. Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

    PubMed Central

    Schmeling, Nadine; Konietzny, Roman; Sieffert, Daniel; Rölling, Patrick

    2010-01-01

    Summary Functionalized copolyimides continue to attract much attention as membrane materials because they can fulfill the demands for industrial applications. Thus not only good separation characteristics but also high temperature stability and chemical resistance are required. Furthermore, it is very important that membrane materials are resistant to plasticization since it has been shown that this phenomenon leads to a significant increase in permeability with a dramatic loss in selectivity. Plasticization effects occur with most polymer membranes at high CO2 concentrations and pressures, respectively. Plasticization effects are also observed with higher hydrocarbons such as propylene, propane, aromatics or sulfur containing aromatics. Unfortunately, these components are present in mixtures of high commercial relevance and can be separated economically by single membrane units or hybrid processes where conventional separation units are combined with membrane-based processes. In this paper the advantages of carboxy group containing 6FDA (4,4′-hexafluoroisopropylidene diphthalic anhydride) -copolyimides are discussed based on the experimental results for non cross-linked, ionically and covalently cross-linked membrane materials with respect to the separation of olefins/paraffins, e.g. propylene/propane, aromatic/aliphatic separation e.g. benzene/cyclohexane as well as high pressure gas separations, e.g. CO2/CH4 mixtures. In addition, opportunities for implementing the membrane units in conventional separation processes are discussed. PMID:20978620

  20. Persistent Effectivity of Gas Plasma-Treated, Long Time-Stored Liquid on Epithelial Cell Adhesion Capacity and Membrane Morphology

    PubMed Central

    Hoentsch, Maxi; Bussiahn, René; Rebl, Henrike; Bergemann, Claudia; Eggert, Martin; Frank, Marcus; von Woedtke, Thomas; Nebe, Barbara

    2014-01-01

    Research in plasma medicine includes a major interest in understanding gas plasma-cell interactions. The immediate application of gas plasma in vitro inhibits cell attachment, vitality and cell-cell contacts via the liquid. Interestingly, in our novel experiments described here we found that the liquid-mediated plasma effect is long-lasting after storage up to seven days; i. e. the liquid preserves the characteristics once induced by the argon plasma. Therefore, the complete Dulbecco's Modified Eagle cell culture medium was argon plasma-treated (atmospheric pressure, kINPen09) for 60 s, stored for several days (1, 4 and 7 d) at 37°C and added to a confluent mouse hepatocyte epithelial cell (mHepR1) monolayer. Impaired tight junction architecture as well as shortened microvilli on the cell membrane could be observed, which was accompanied by the loss of cell adhesion capacity. Online-monitoring of vital cells revealed a reduced cell respiration. Our first time-dependent analysis of plasma-treated medium revealed that temperature, hydrogen peroxide production, pH and oxygen content can be excluded as initiators of cell physiological and morphological changes. The here observed persisting biological effects in plasma-treated liquids could open new medical applications in dentistry and orthopaedics. PMID:25170906

  1. Monitoring of N-methyl carbamate pesticide residues in water using hollow fibre supported liquid membrane and solid phase extraction

    NASA Astrophysics Data System (ADS)

    Msagati, Titus A. M.; Mamba, Bhekie B.

    The aim of this work was to develop a method for the determination of N-methyl carbamates in water involving hollow fibre supported liquid membrane (HFSLM) and solid phase extraction (SPE) as sample preparation methods. Four N-methyl carbamate pesticides, aldicarb, carbaryl, carbofuran and methiocarb sulfoxide, were simultaneously extracted and analysed by a liquid chromatograph with a diode array detector (LC-UV/DAD) and a liquid chromatograph coupled to a ion trap quadrupole mass spectrometer (LC-ESI-MS). The high performance liquid chromatography (HPLC) separation of carabamate extracts was performed on a C18 column with water-acetonitrile as the mobile phase. The mass spectrometry analyses were carried out in the positive mode, operating under both the selected ion monitoring (SIM) and full scan modes. The solid phase recoveries of the extracts ranged between 8% and 98%, with aldicarb having the highest recoveries, followed by carbaryl, carbofuran and methiocarb had the lowest recovery. The HFSLM recovery ranged between 8% and 58% and the order of recovery was similar to the SPE trend. Factors controlling the efficiency of the HFSLM extraction such as sample pH, stripping phase pH, enrichment time, stirring speed as well as organic solvent used for entrapment of analytes, were optimised to achieve the highest enrichment factors.

  2. Pervaporation and Vapor Permeation Tutorial: Membrane Processes for the Selective Separation of Liquid and Vapor Mixtures

    EPA Science Inventory

    Pervaporation and vapor permeation are membrane-based processes proposed as alternatives to conventional separation technologies. Applications range from organic solvent removal from water, ethanol or butanol recovery from fermentation broths, solvent/biofuel dehydration to meet ...

  3. Pervaporation & Vapor Permeation Membrane Processes for the Selective Separation of Liquid and Vapor Mixtures

    EPA Science Inventory

    Pervaporation and vapor permeation are membrane-based processes which have been proposed as alternatives to conventional separation technologies. Applications range from organic solvent removal from water, ethanol or butanol recovery from dilute fermentation broths, solvent/biofu...

  4. Characterization of carbon dioxide transfer in a hollow fiber membrane module as a solution for gas-liquid transfer in microgravity conditions.

    NASA Astrophysics Data System (ADS)

    Farges, Berangere; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-F.

    In microgravity, one of the major difficulties encountered in closed photosynthetic reactors is the gas-liquid transfer with the necessity to provide CO2 (carbon source, pH control) and to recover the produced O2 . Indeed, reduced gravity is expected to modify gas liquid transfer and liquid phase mixing characteristics inside photobioreactors conceived to regenerate atmosphere of closed life-support systems. To obtain efficient mass transfer conditions and mixing of phases, several solutions are possible: use of rotating reactor (centrifugal field), use of forced, co-current convective reactor with gas-liquid separator and use of membrane modules. In terms of space process engineering, the membrane reactor can be a valuable alternative in which the gas and liquid phases are separated with a selectively permeable membrane. The rate-limiting factors in this reactor were demonstrated to be the surface of membrane A needed for diffusion of gases and the CO2 and O2 mass transfer coefficients in the liquid phase kL. How-ever, the major advantages of the membrane reactor are that it is composed of a hydrophobic membrane (here PTFE) which showed a high hydrophobicity, an important chemical resis-tance, a very long term stability and overall which is favourable to gas transfer. Moreover, the volumetric mass transfer coefficients are sufficiently high to build compact systems with small footprints, no complex rotating devices and lighter weights. This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient CO kL 2 obtained in case of an absorption experiment at pH = 8 using the

  5. Self-Assembly and Orientation of Hydrogen-Bonded Oligothiophene Polymorphs at Liquid-Membrane-Liquid Interfaces

    SciTech Connect

    Tevis, Ian D; Palmer, Liam C; Herman, David J; Murray, Ian P; Stone, David A; Stupp, Samuel I

    2012-03-15

    One of the challenges in organic systems with semiconducting function is the achievement of molecular orientation over large scales. We report here on the use of self-assembly kinetics to control long-range orientation of a quarterthiophene derivative designed to combine intermolecular π-π stacking and hydrogen bonding among amide groups. Assembly of these molecules in the solution phase is prevented by the hydrogen-bond-accepting solvent tetrahydrofuran, whereas formation of H-aggregates is facilitated in toluene. Rapid evaporation of solvent in a solution of the quarterthiophene in a 2:1:1 mixture of 1,4-dioxane/tetrahydrofuran/toluene leads to self-assembly of kinetically trapped mats of bundled fibers. In great contrast, slow drying in a toluene atmosphere leads to the homogeneous nucleation and growth of ordered structures shaped as rhombohedra or hexagonal prisms depending on concentration. Furthermore, exceedingly slow delivery of toluene from a high molecular weight polymer solution into the system through a porous aluminum oxide membrane results in the growth of highly oriented hexagonal prisms perpendicular to the interface. The amide groups of the compound likely adsorb onto the polar aluminum oxide surface and direct the self-assembly pathway toward heterogeneous nucleation and growth to form hexagonal prisms. We propose that the oriented prismatic polymorph results from the synergy of surface interactions rooted in hydrogen bonding on the solid membrane and the slow kinetics of self-assembly. These observations demonstrate how self-assembly conditions can be used to guide the supramolecular energy landscape to generate vastly different structures. These fundamental principles allowed us to grow oriented prismatic assemblies on transparent indium-doped tin oxide electrodes, which are of interest in organic electronics.

  6. Self-assembly and orientation of hydrogen-bonded oligothiophene polymorphs at liquid-membrane-liquid interfaces.

    PubMed

    Tevis, Ian D; Palmer, Liam C; Herman, David J; Murray, Ian P; Stone, David A; Stupp, Samuel I

    2011-10-19

    One of the challenges in organic systems with semiconducting function is the achievement of molecular orientation over large scales. We report here on the use of self-assembly kinetics to control long-range orientation of a quarterthiophene derivative designed to combine intermolecular π-π stacking and hydrogen bonding among amide groups. Assembly of these molecules in the solution phase is prevented by the hydrogen-bond-accepting solvent tetrahydrofuran, whereas formation of H-aggregates is facilitated in toluene. Rapid evaporation of solvent in a solution of the quarterthiophene in a 2:1:1 mixture of 1,4-dioxane/tetrahydrofuran/toluene leads to self-assembly of kinetically trapped mats of bundled fibers. In great contrast, slow drying in a toluene atmosphere leads to the homogeneous nucleation and growth of ordered structures shaped as rhombohedra or hexagonal prisms depending on concentration. Furthermore, exceedingly slow delivery of toluene from a high molecular weight polymer solution into the system through a porous aluminum oxide membrane results in the growth of highly oriented hexagonal prisms perpendicular to the interface. The amide groups of the compound likely adsorb onto the polar aluminum oxide surface and direct the self-assembly pathway toward heterogeneous nucleation and growth to form hexagonal prisms. We propose that the oriented prismatic polymorph results from the synergy of surface interactions rooted in hydrogen bonding on the solid membrane and the slow kinetics of self-assembly. These observations demonstrate how self-assembly conditions can be used to guide the supramolecular energy landscape to generate vastly different structures. These fundamental principles allowed us to grow oriented prismatic assemblies on transparent indium-doped tin oxide electrodes, which are of interest in organic electronics.

  7. Ideal CO2/Light Gas Separation Performance of Poly(vinylimidazolium) Membranes and Poly(vinylimidazolium)-Ionic Liquid Composite Films

    SciTech Connect

    Carlisle, TK; Wiesenauer, EF; Nicodemus, GD; Gin, DL; Noble, RD

    2013-01-23

    Six vinyl-based, imidazolium room-temperature ionic liquid (RTIL) monomers were synthesized and photopolymerized to form dense poly(RTIL) membranes. The effect of polymer backbone (i.e., poly(ethylene), poly(styrene), and poly(acrylate)) and functional cationic substituent (e.g., alkyl, fluoroalkyl, oligo(ethylene glycol), and disiloxane) on ideal CO2/N-2 and CO2/CH4 membrane separation performance was investigated. The vinyl-based poly(RTIL)s were found to be generally less CO2-selective compared to analogous styrene- and acrylate-based poly(RTIL)s. The CO2 permeability of n-hexyl-(69 barrers) and disiloxane- (130 barrers) substituted vinyl-based poly(RTIL)s were found to be exceptionally larger than that of previously studied styrene and acrylate poly(RTIL)s. The CO2 selectivity of oligo(ethylene glycol)-functionalized vinyl poly(RTIL)s was enhanced, and the CO2 permeability was reduced when compared to the n-hexyl-substituted vinyl-based poly(RTIL). Nominal improvement in CO2/CH4 selectivity was observed upon fluorination of the n-hexyl vinyl-based poly(RTIL), with no observed change in CO2 permeability. However, rather dramatic improvements in both CO2 permeability and selectivity were observed upon blending 20 mol % RTIL (emim Tf2N) into the n-hexyl- and disiloxane-functionalized vinyl poly(RTIL)s to form solid liquid composite films.

  8. Extraction of lutetium(III) from aqueous solutions by employing a single fibre-supported liquid membrane.

    PubMed

    Trtić-Petrović, Tatjana M; Kumrić, Ksenija R; Dordević, Jelena S; Vladisavljević, Goran T

    2010-07-01

    Transport behaviour of Lu(III) across a polypropylene hollow fibre-supported liquid membrane containing di(2-ethylhexyl)phosphoric acid (DEHPA) in dihexyl ether as a carrier has been studied. The donor phase was LuCl(3) in the buffer solution consisting of 0.2 M sodium acetate at pH 2.5-5.0. A miniaturised system with a single hollow fibre has been operated in a batch mode. The concentration of Lu(III) was determined by indirect voltammetric method using Zn-EDTA complex. The effect of pH and volume of the donor phase, DEHPA concentration in the organic (liquid membrane) phase, the time of extraction and the content of the acceptor phase on the Lu(III) extraction and stripping behaviour was investigated. The results were discussed in terms of the pertraction and removal efficiency, the memory effect and the mean flux of Lu(III). The optimal conditions for the removal of (177)Lu(III) from labelled (177)Lu-radiopharmaceuticals were discussed and identified. The removal efficiency of Lu(III) greater than 99% was achieved at pH of the donor phase between 3.5 and 5.0 using DEHPA concentration in the organic phase of 0.47 M and the ratio of the donor to the acceptor phase of 182.

  9. Deashing of coal liquids with ceramic membrane microfiltration and diafiltration. Final technical report, August 4, 1992--September 30, 1995

    SciTech Connect

    1996-03-01

    Removal of mineral matter from liquid hydrocarbons derived from the direct liquefaction of coal is required for product acceptability. Current methods include critical solvent Deashing and filtration, both of which produce an ash reject stream containing up to 15% of the liquid hydrocarbon product. This program was directed towards development of an improved process for deashing and recovery of coal-derived residual oil: the use of ceramic membranes for high-temperature microfiltration and diafiltration. Using laboratory scale ceramic membrane modules, samples of a coal-derived residual oil containing ash were processed by crossflow microfiltration, followed by solvent addition and refiltration (diafiltration). Excellent recovery of deashed residual oil was demonstrated. Data from this program were used to develop preliminary estimates for production system capital and operating costs that will be used to assess economic feasibility. The first objective of this program was to demonstrate technical feasibility of crossflow microfiltration (MF) for removal of mineral matter from a coal derived residual oil. A second objective was to demonstrate technical feasibility of diafiltration of W concentrate using a hydrocarbon diluent.

  10. Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments

    USGS Publications Warehouse

    Griffin, Dale W.; Gonzalez, C.; Teigell, N.; Petrosky, T.; Northup, D.E.; Lyles, M.

    2011-01-01

    The influence of sample-collection-time on the recovery of culturable airborne microorganisms using a low-flow-rate membrane-filtration unit and a high-flow-rate liquid impinger were investigated. Differences in recoveries were investigated in four different atmospheric environments, one mid-oceanic at an altitude of ~10.0 m, one on a mountain top at an altitude of ~3,000.0 m, one at ~1.0 m altitude in Tallahassee, Florida, and one at ~1.0 m above ground in a subterranean-cave. Regarding use of membrane filtration, a common trend was observed: the shorter the collection period, the higher the recovery of culturable bacteria and fungi. These data also demonstrated that lower culturable counts were common in the more remote mid-oceanic and mountain-top atmospheric environments with bacteria, fungi, and total numbers averaging (by sample time or method categories) <3.0 colony-forming units (CFU) m -3. At the Florida and subterranean sites, the lowest average count noted was 3.5 bacteria CFU m-3, and the highest averaged 140.4 total CFU m-3. When atmospheric temperature allowed use, the high-volume liquid impinger utilized in this study resulted in much higher recoveries, as much as 10?? greater in a number of the categories (bacterial, fungal, and total CFU). Together, these data illustrated that (1) the high-volume liquid impinger is clearly superior to membrane filtration for aeromicrobiology studies if start-up costs are not an issue and temperature permits use; (2) although membrane filtration is more cost friendly and has a 'typically' wider operational range, its limits include loss of cell viability with increased sample time and issues with effectively extracting nucleic acids for community-based analyses; (3) the ability to recover culturable microorganisms is limited in 'extreme' atmospheric environments and thus the use of a 'limited' methodology in these environments must be taken into account; and (4) the atmosphere culls, i.e., everything is not

  11. Gas-phase and liquid-phase pre-irradiation grafting of AAc onto LDPE and HDPE films for pervaporation membranes

    NASA Astrophysics Data System (ADS)

    Zhigong, Rao; Guixiang, Li; Sugo, Takanobu; Okamoto, Jiro

    A study has been made on gas-phase and liquid-phase pre-irradiation grafting of acrylic acid onto LDPE and HDPE films for pervaporation membranes of ethanol-water mixtures. It was found that the degree of grafting, percent volume change of grafted membranes and length of grafting chains depend on the methods of grafting, crystal state of substrate films and diffusion rate of the monomer in the films. The pervaporation characteristics of grafted membranes is influenced directly by the surface hydrophilicity of grafted membranes, temperature of the feed, degree of grafting, crosslinking of grafted chains and alkaline metal ions in the functional groups. The potassium ion exchange membrane of HDPE synthesized by gas-phase grafting has better pervaporation efficiency. At 80 wt% ethanol in the feed, 25°C feed temperature and 70% degree of grafting a grafted membrane has a 0.65 kg/m 2h flux and a separation factor of 20.

  12. Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking

    NASA Astrophysics Data System (ADS)

    Wu, Hsiao-Mei; Lin, Ying-Hsiu; Yen, Tzu-Chi; Hsieh, Chia-Lung

    2016-02-01

    Lipid rafts are membrane nanodomains that facilitate important cell functions. Despite recent advances in identifying the biological significance of rafts, nature and regulation mechanism of rafts are largely unknown due to the difficulty of resolving dynamic molecular interaction of rafts at the nanoscale. Here, we investigate organization and single-molecule dynamics of rafts by monitoring lateral diffusion of single molecules in raft-containing reconstituted membranes supported on mica substrates. Using high-speed interferometric scattering (iSCAT) optical microscopy and small gold nanoparticles as labels, motion of single lipids is recorded via single-particle tracking (SPT) with nanometer spatial precision and microsecond temporal resolution. Processes of single molecules partitioning into and escaping from the raft-mimetic liquid-ordered (Lo) domains are directly visualized in a continuous manner with unprecedented clarity. Importantly, we observe subdiffusion of saturated lipids in the Lo domain in microsecond timescale, indicating the nanoscopic heterogeneous molecular arrangement of the Lo domain. Further analysis of the diffusion trajectory shows the presence of nano-subdomains of the Lo phase, as small as 10 nm, which transiently trap the lipids. Our results provide the first experimental evidence of non-uniform molecular organization of the Lo phase, giving a new view of how rafts recruit and confine molecules in cell membranes.

  13. Nanoscopic substructures of raft-mimetic liquid-ordered membrane domains revealed by high-speed single-particle tracking

    PubMed Central

    Wu, Hsiao-Mei; Lin, Ying-Hsiu; Yen, Tzu-Chi; Hsieh, Chia-Lung

    2016-01-01

    Lipid rafts are membrane nanodomains that facilitate important cell functions. Despite recent advances in identifying the biological significance of rafts, nature and regulation mechanism of rafts are largely unknown due to the difficulty of resolving dynamic molecular interaction of rafts at the nanoscale. Here, we investigate organization and single-molecule dynamics of rafts by monitoring lateral diffusion of single molecules in raft-containing reconstituted membranes supported on mica substrates. Using high-speed interferometric scattering (iSCAT) optical microscopy and small gold nanoparticles as labels, motion of single lipids is recorded via single-particle tracking (SPT) with nanometer spatial precision and microsecond temporal resolution. Processes of single molecules partitioning into and escaping from the raft-mimetic liquid-ordered (Lo) domains are directly visualized in a continuous manner with unprecedented clarity. Importantly, we observe subdiffusion of saturated lipids in the Lo domain in microsecond timescale, indicating the nanoscopic heterogeneous molecular arrangement of the Lo domain. Further analysis of the diffusion trajectory shows the presence of nano-subdomains of the Lo phase, as small as 10 nm, which transiently trap the lipids. Our results provide the first experimental evidence of non-uniform molecular organization of the Lo phase, giving a new view of how rafts recruit and confine molecules in cell membranes. PMID:26861908

  14. Ionic liquids effects on the permeability of photosynthetic membranes probed by the electrochromic shift of endogenous carotenoids.

    PubMed

    Malferrari, Marco; Malferrari, Danilo; Francia, Francesco; Galletti, Paola; Tagliavini, Emilio; Venturoli, Giovanni

    2015-11-01

    Ionic liquids (ILs) are promising materials exploited as solvents and media in many innovative applications, some already used at the industrial scale. The chemical structure and physicochemical properties of ILs can differ significantly according to the specific applications for which they have been synthesized. As a consequence, their interaction with biological entities and toxicity can vary substantially. To select highly effective and minimally harmful ILs, these properties need to be investigated. Here we use the so called chromatophores--protein-phospholipid membrane vesicles obtained from the photosynthetic bacterium Rhodobacter sphaeroides--to assess the effects of imidazolinium and pyrrolidinium ILs, with chloride or dicyanamide as counter anions, on the ionic permeability of a native biological membrane. The extent and modalities by which these ILs affect the ionic conductivity can be studied in chromatophores by analyzing the electrochromic response of endogenous carotenoids, acting as an intramembrane voltmeter at the molecular level. We show that chromatophores represent an in vitro experimental model suitable to probe permeability changes induced in cell membranes by ILs differing in chemical nature, degree of oxygenation of the cationic moiety and counter anion.

  15. Facile method of fabricating Sn nanoparticle monolayer using solid-supported liquid-crystalline phospholipid membrane

    NASA Astrophysics Data System (ADS)

    An, Hyeun Hwan; Kim, Jung Hoon; Lee, Seung Jae; Han, Won Bae; Lee, Jong Ho; Kim, Hee-Soo; Suh, Sang Hee; Yoon, Im Taek; Shon, Yoon; Yoon, Chong Seung

    2011-08-01

    1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) phospholipid membrane was used to fabricate a tightly packed 2-dimensional array of Sn nanoparticles through direct deposition of Sn on the DOPC membrane. Major advantage of the proposed method was that the vertical ordering of the nanoparticles extended to a centimeter (2 cm × 2 cm substrate) scale in the as-prepared state. It was also shown that the particle size and morphology were altered depending on processing conditions. Experimental evidences indicated that the Sn nanoparticle surface, which spontaneously oxidized during deposition, was encapsulated by the DOPC molecules. After removing the encapsulating lipid layer, the oxide-covered Sn nanoparticles exhibited strong photoluminescence. It was also demonstrated that the Sn particle morphology and ordering are related to the lipid membrane structure and chemistry. The proposed method can be easily extended to other metals that are susceptible to oxidation to produce various metal oxide nanoparticles.

  16. Enzymatic membrane reactor for full saccharification of ionic liquid-pretreated microcrystalline cellulose.

    PubMed

    Lozano, Pedro; Bernal, Berenice; Jara, Antonio G; Belleville, Marie-Pierre

    2014-01-01

    Ultrafiltration reactors based on polymeric or ceramic membranes were shown to be suitable catalytic systems for fast enzymatic saccharification of cellulose, allowing the full recovery and reuse of enzymes. By pre-treating cellulose with the IL 1-butyl-3-methylimidazolium chloride, the suitability of this substrate for enzymatic saccharification in a reactor based on polymeric ultrafiltration membranes was demonstrated, leading to 95% cellulose hydrolysis in 4h at 50°C. The filtration process gave a clear glucose solution (up to 113 mM) at constant permeate flow (24.7 L h(-1) m(-2)), allowing the enzyme to be reused for 9 operation cycles under semi-continuous operation, without any loss of enzyme activity. Under continuous operation mode and using ceramic ultrafiltration membranes at different residence times, the enzymatic reactor showed constant profiles in both the permeate flow rate and the glucose concentration, demonstrating the excellent suitability of the proposed approach for the saccharification of cellulose.

  17. Membrane separation processes for liquid hydrocarbons and gases in the petrochemical industry

    SciTech Connect

    Not Available

    1989-09-01

    OIP and Allied Signal Corporation have completed a joint project exploring new applications of membrane separation technology for the petrochemical and related industries. These applications have the potential for major energy savings compared to more traditional distillation and chemical absorption processes. This technical case study provides an overview of the DOE-Allied Signal membrane development project. It highlights the field testing of modified cellulose acetate membrane systems for acid gas removal at two commercial natural gas plants. The document is aimed at making field test and data analysis results available to other researchers and private industry in a timely manner. This case study discusses project status; summarizes field testing efforts; and reviews potential technology impacts in terms of applications, energy savings, and preliminary economics.

  18. Confinement of Ionic Liquids in Nanocages: Tailoring the Molecular Sieving Properties of ZIF-8 for Membrane-Based CO2 Capture.

    PubMed

    Ban, Yujie; Li, Zhengjie; Li, Yanshuo; Peng, Yuan; Jin, Hua; Jiao, Wenmei; Guo, Ang; Wang, Po; Yang, Qingyuan; Zhong, Chongli; Yang, Weishen

    2015-12-14

    Fine-tuning of effective pore size of microporous materials is necessary to achieve precise molecular sieving properties. Herein, we demonstrate that room temperature ionic liquids can be used as cavity occupants for modification of the microenvironment of MOF nanocages. Targeting CO2 capture applications, we tailored the effective cage size of ZIF-8 to be between CO2 and N2 by confining an imidazolium-based ionic liquid [bmim][Tf2 N] into ZIF-8's SOD cages by in-situ ionothermal synthesis. Mixed matrix membranes derived from ionic liquid-modified ZIF-8 exhibited remarkable combinations of permeability and selectivity that transcend the upper bound of polymer membranes for CO2 /N2 and CO2 /CH4 separation. We observed an unusual response of the membranes to varying pressure, that is, an increase in the CO2 /CH4 separation factor with pressure, which is highly desirable for practical applications in natural gas upgrading.

  19. Highly selective separation of carbon dioxide from nitrogen and methane by nitrile/glycol-difunctionalized ionic liquids in supported ionic liquid membranes (SILMs).

    PubMed

    Hojniak, Sandra D; Silverwood, Ian P; Khan, Asim Laeeq; Vankelecom, Ivo F J; Dehaen, Wim; Kazarian, Sergei G; Binnemans, Koen

    2014-07-03

    Novel difunctionalized ionic liquids (ILs) containing a triethylene glycol monomethyl ether chain and a nitrile group on a pyrrolidinium or imidazolium cation have been synthesized and incorporated into supported ionic liquid membranes (SILMs). These ILs exhibit ca. 2.3 times higher CO2/N2 and CO2/CH4 gas separation selectivities than analogous ILs functionalized only with a glycol chain. Although the glycol moiety ensures room temperature liquidity of the pyrrolidinium and imidazolium ILs, the two classes of ILs benefit from the presence of a nitrile group in different ways. The difunctionalized pyrrolidinium ILs exhibit an increase in CO2 permeance, whereas the permeances of the contaminant gases rise negligibly, resulting in high gas separation selectivities. In the imidazolium ILs, the presence of a nitrile group does not always increase the CO2 permeance nor does it increase the CO2 solubility, as showed in situ by the ATR-FTIR spectroscopic method. High selectivity of these ILs is caused by the considerably reduced permeances of N2 and CH4, most likely due to the ability of the -CN group to reject the nonpolar contaminant gases. Apart from the CO2 solubility, IL-CO2 interactions and IL swelling were studied with the in situ ATR-FTIR spectroscopy. Different strengths of the IL-CO2 interactions were found to be the major difference between the two classes of ILs. The difunctionalized ILs interacted stronger with CO2 than the glycol-functionalized ILs, as manifested in the smaller bandwidths of the bending mode band of CO2 for the latter.

  20. Purification of inkjet ink from water using liquid phase, electric discharge polymerization and cellulosic membrane filtration.

    PubMed

    Jordan, Alexander T; Hsieh, Jeffery S; Lee, Daniel T

    2013-01-01

    A method to separate inkjet ink from water was developed using a liquid phase, electric discharge process. The liquid phase, electric discharge process with filtration or sedimentation was shown to remove 97% of inkjet ink from solutions containing between 0.1-0.8 g/L and was consistent over a range of treatment conditions. Additionally, particle size analysis of treated allyl alcohol and treated propanol confirmed the electric discharge treatment has a polymerization mechanism, and small molecule analysis of treated methanol using gas chromatography and mass spectroscopy confirmed the mechanism was free radical initiated polymerization.

  1. Technical feasibility study of electrolytic ion transfer membranes for radioactive liquid waste processing

    SciTech Connect

    Not Available

    1982-08-11

    Results are presented of a test program designed to determine the technical feasibility of INNOVA Ion Transfer Membranes (ITM) to separate radionuclides from waste streams at N Reactor. The ITM system was tested using the following test solutions, which either chemically simulated or duplicated the radioactive waste streams generated at N Reactor: TURCO 4512A - /sup 59/Co, 4% Na/sub 2/So/sub 4/ - /sup 59/Fe, and Ion Exchange Resin Regeneration (IXR) waste from an irradiated fuel storage basin. In addition, the ITM construction material was tested to determine its resistance to a radioactive environment. To assure that the ITM membranes could withstand a radioactive environment, samples of the ITM membrane material were exposed to high doses of gamma radiation and then tested for change in burst strength. The irradiated membranes did not show significant signs of degradation until a total gamma radiation exposure of 10/sup 7/ Rads was reached. Extrapolation of this data strongly suggests that the membrane life expectancy in a radiation environment is good. The following recommendations were made. Sequential unialysis be investigated for processing IXR waste. Reactor Decontamination Waste be treated by the Oxidation Reduction Coagulation cell prior to ITM processing to confirm pre-treatment feasibility. The Oxidation Reduction Coagulation cell be developed for other N Area applications. An ITM unialysis system be developed for selective radionuclide extraction from irradiated fuel storage basins. The ITM economic feasibility be determined on the applications tested in this report. A unialysis ITM system be tested for extraction of radionuclides from electropolish decontamination wastes.

  2. Application of Membrane Separation Technology for Removal of Microorganisms from Unpasteurized Liquid Egg White

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Liquid egg products provide a unique, well-balanced source of nutrients to the diet. Pasteurization (56.6 degree C; 3.5 min) is used industry wide to reduce the microbial load and ensure elimination of salmonella contaminants. However, pasteurization may be inadequate for eliminating salmonella in c...

  3. Polyphosphazene-Based Proton-Exchange Membranes for Direct Liquid Methanol Fuel Cells

    DTIC Science & Technology

    2005-11-04

    sulfonic acid site), as shown in Figure 9 and (ii) the neutralization of some sulfonic acid groups in SPOP due to complexation with PBI (see Figure 10...polybenzimidazole (for acid -base complexation crosslinking) prior to membrane casting. Some of the films containing poly[bis(3- methylphenoxy)phosphazene...sulfonated poly[bis(phenoxy)phosphazene] (SPOP) and polybenzimidazole ( PBI ) worked particularly well in a DMFC (at 60oC 1.0 M methanol, and ambient

  4. In-sample acetylation-non-porous membrane-assisted liquid-liquid extraction for the determination of parabens and triclosan in water samples.

    PubMed

    Villaverde-de-Sáa, Eugenia; González-Mariño, Iria; Quintana, José Benito; Rodil, Rosario; Rodríguez, Isaac; Cela, Rafael

    2010-07-01

    A procedure for the determination of seven parabens (esters of 4-hydroxybenzoic acid), including the distinction between branched and linear isomers of propyl- and butyl-parabens and triclosan in water samples, was developed and evaluated. The procedure includes in-sample acetylation-non-porous membrane-assisted liquid-liquid extraction and large volume injection-gas chromatography-ion trap-tandem mass spectrometry. Different derivatisation strategies were considered, i.e. post-extraction silylation with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide and in situ acylation with acetic anhydride (Ac(2)O) and isobutylchloroformate. Moreover, acceptor solvent and the basic catalyser of the acylation reaction were investigated. Thus, in situ derivatisation with Ac(2)O and potassium hydrogenphosphate (as basic catalyser) was selected. Potassium hydrogenphosphate overcomes some drawbacks of other basic catalysers, e.g. toxicity and bubble formation, while leads to higher responses. Subsequently, other experimental variables affecting derivatisation-extraction yield such as pre-stirring time, salt addition and volume of Ac(2)O were optimised by an experimental design approach. Under optimised conditions, the proposed method achieved detection limits from 0.1 to 1.4 ng L(-1) for a sample volume of 18 mL and extraction efficiencies, estimated by comparison with liquid-liquid extraction, between 46% (for methyl- and ethyl-parabens) and 110% (for benzylparaben). The reported sample preparation approach is free of matrix effects for parabens but affected for triclosan with a reduction of approximately 40% when wastewater samples are analysed; therefore, both internal and external calibration can be used as quantification techniques for parabens, but internal standard calibration is mandatory for triclosan. The application of the method to real samples revealed the presence of these compounds in raw wastewater at concentrations up to 26 ng mL(-1), the prevalence of the

  5. Effect of water on life prediction of liquid silicone rubber seals in polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Cui, Tong; Chao, Y. J.; Chen, X. M.; Van Zee, J. W.

    Liquid silicone rubber (LSR) is a popular gasket or seal material and is also promising for sealing applications in polymer electrolyte membrane fuel cell (PEMFC). The durability of the LSR gasket/seals in PEMFC is one of the major issues in commercialization of PEMFC. As there are water and humidity inside PEMFC and polymers such as LSR generally exhibit stress relaxation property, it is important to understand the effect of water on the compression stress relaxation of LSR. Our test results show that water has no influence on the stress relaxation in the beginning, but it accelerates the relaxation after a certain time. Higher temperature makes this transition occurs earlier. Further studies reveal that water can diffuse into LSR and exists as free water molecules. It may attack the backbones of the polymer and thus accelerate the stress relaxation. High temperature tends to aggravate the attack of water to the polymer chains. The attack coexists with the thermal degradation of the LSR.

  6. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

    PubMed Central

    Akhmetshina, Alsu A.; Davletbaeva, Ilsiya M.; Grebenschikova, Ekaterina S.; Sazanova, Tatyana S.; Petukhov, Anton N.; Atlaskin, Artem A.; Razov, Evgeny N.; Zaripov, Ilnaz I.; Martins, Carla F.; Neves, Luísa A.; Vorotyntsev, Ilya V.

    2015-01-01

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S. PMID:26729177

  7. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

    PubMed

    Akhmetshina, Alsu A; Davletbaeva, Ilsiya M; Grebenschikova, Ekaterina S; Sazanova, Tatyana S; Petukhov, Anton N; Atlaskin, Artem A; Razov, Evgeny N; Zaripov, Ilnaz I; Martins, Carla F; Neves, Luísa A; Vorotyntsev, Ilya V

    2015-12-30

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf₂N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N₂, NH₃, H₂S, and CO₂ gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF₆] and [emim][Tf₂N]. The modification of SILMs by nanosize silica particles leads to an increase of NH₃ separation relatively to CO₂ or H₂S.

  8. Electro-enhanced hollow fiber membrane liquid phase microextraction of Cr(VI) oxoanions in drinking water samples.

    PubMed

    Chanthasakda, Nattaporn; Nitiyanontakit, Sira; Varanusupakul, Pakorn

    2016-02-01

    Hollow fiber membrane liquid phase microextraction (HF-LPME) of metal oxoanions was studied using an ionic carrier enhanced by the application of an electric field (electro-enhanced HF-LPME). The Cr(VI) oxoanion was used as the model. The transportation of Cr(VI) oxoanions across the supported liquid membrane (SLM) was explored via the ion-exchange process and electrokinetic migration. The type of SLM, type of acceptor solution, extraction time, electric potential, and stirring rate were investigated and optimized using MilliQ water. Electro-enhanced HF-LPME provided a much higher enrichment factor compared to conventional HF-LPME (no electric potential) for the same extraction time. A mixture of an anion exchange carrier (methyltrialkyl-ammonium chloride, Aliquat 336) in the SLM facilitated the transportation of Cr(VI) oxoanions. The SLM that gave the best performance was 1-heptanol mixed with 5% Aliquat 336 with 1M NaOH as the acceptor. Linearity was obtained in the working range of 3-15 µg L(-1) Cr(VI) (R(2)>0.99) at 30 V with a 5 min extraction time. The limit of detection was below 5 µg L(-1). The relative standard deviation was less than 12%. The method was applied to drinking water samples. The recoveries of spiked Cr(VI) in drinking water samples were in the range of 96-101% based on the matrix-matched calibration curves. The method was limited to samples containing low levels of ions due to the occurrence of electrolysis. The type of SLM, particularly regarding its resistance, should be tuned to control this problematic phenomenon.

  9. Hollow fiber membrane-coated functionalized polymeric ionic liquid capsules for direct analysis of estrogens in milk samples.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-02-01

    Protein removal process is always time-consuming for the analysis of milk samples. In this work, hollow fiber membrane-coated functionalized polymeric ionic liquid (HF-PIL) capsules were synthesized and used as solid-phase microextraction (SPME) sorbent for direct analysis of estrogens in milk samples. The functionalized PIL monolith sorbent was obtained by copolymerization between 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer and 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL-crosslinking agent. A group of four capsules were installed as SPME device, to determine four kinds of estrogens (estrone, diethylstilbestrol, hexestrol, and 17α-ethynylestradiol) in milk samples, coupled to high performance liquid chromatography. Extraction and desorption conditions were optimized to get satisfactory extraction efficiency. Good linearity was obtained in the range of 5-200 μg L(-1). The limits of detection were 1 μg L(-1) for diethylstilbestrol and 2 μg L(-1) for 17α-ethynylestradiol, estrone, and hexestrol. The present method was applied to analyze the model analytes in different milk samples. Relative recoveries were in the range of 85.5-112%. The HF-PIL SPME capsules showed satisfactory extraction efficiency and high resistance to sample matrix interference.

  10. Modeling efficiency and water balance in PEM fuel cell systems with liquid fuel processing and hydrogen membranes

    NASA Astrophysics Data System (ADS)

    Pearlman, Joshua B.; Bhargav, Atul; Shields, Eric B.; Jackson, Gregory S.; Hearn, Patrick L.

    Integrating PEM fuel cells effectively with liquid hydrocarbon reforming requires careful system analysis to assess trade-offs associated with H 2 production, purification, and overall water balance. To this end, a model of a PEM fuel cell system integrated with an autothermal reformer for liquid hydrocarbon fuels (modeled as C 12H 23) and with H 2 purification in a water-gas-shift/membrane reactor is developed to do iterative calculations for mass, species, and energy balances at a component and system level. The model evaluates system efficiency with parasitic loads (from compressors, pumps, and cooling fans), system water balance, and component operating temperatures/pressures. Model results for a 5-kW fuel cell generator show that with state-of-the-art PEM fuel cell polarization curves, thermal efficiencies >30% can be achieved when power densities are low enough for operating voltages >0.72 V per cell. Efficiency can be increased by operating the reformer at steam-to-carbon ratios as high as constraints related to stable reactor temperatures allow. Decreasing ambient temperature improves system water balance and increases efficiency through parasitic load reduction. The baseline configuration studied herein sustained water balance for ambient temperatures ≤35 °C at full power and ≤44 °C at half power with efficiencies approaching ∼27 and ∼30%, respectively.

  11. ARSENIC DETERMINATION IN SALINE WATERS UTILIZING A TUBULAR MEMBRANE AS A GAS-LIQUID SEPATRATOR FOR HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

    EPA Science Inventory

    A tubular silicone rubber membrane is evaluated as a gas-liquid separator for the determination of arsenic in saline waters via HG-ICP-MS. The system was optimized in terms of NaBH and HCI concentrations. The intermediate gas and carrier gas were optimized in terms of sensitiity ...

  12. Halogen-free ionic liquid as an additive in zinc(II)-selective electrode: surface analyses as correlated to the membrane activity.

    PubMed

    Al-Asousi, Maryam F; Shoukry, Adel F; Bu-Olayan, Abdul Hadi

    2012-05-30

    Two conventional Zn(II) polyvinyl chloride (PVC) membrane electrodes have been prepared and characterized. They were based on dibenzo-24-crown-8 (DBC) as a neutral carrier, dioctyl phthalate (DOP) as a plasticizer, and potassium tetrakis (p-chlorophenyl) borate, KTpClPB or the halogen-free ionic liquid, tetraoctylammonium dodecylbenzene sulfonate [TOA][DBS] as an additive. The use of ionic liquid has been found to enhance the selectivity of the sensor. For each electrode, the surfaces of two membranes were investigated using X-ray photoelectron, ion-scattering spectroscopy and atomic force microscopy. One of the two membranes was conditioned by soaking it for 24 h in a 1.0×10(-3) M Zn(NO(3))(2) solution and the second was soaked in bi-distilled water for the same interval (24 h). Comparing the two surfaces indicated the following: (a) the high selectivity in case of using [TOA][DBS] as an additive is due to the extra mediation caused by the ionic liquid and (b) the working mechanism of the electrode is based on phase equilibrium at the surface of the membrane associated with ion transport through the bulk of the membrane.

  13. Joining of Ion Transport Membranes Using a Novel Transient Liquid Phase Process

    SciTech Connect

    Darryl P. Butt

    2006-08-30

    The feasibility of a novel transient liquid phase (TLP) joining method has been demonstrated in joining La{sub 0.9}Ca{sub 0.1}FeO{sub 3} materials. Metal oxide powders were processed to form the TLP compositions which were used in the joining process. The method has been successful in producing joint interfaces that effectively disappear, as they are the same material and have the same properties as the joined parts. The feasibility of the method has been demonstrated for a single system, but many systems where the method can potentially be applied have been identified.

  14. Design and development of a self-regenerative contained-liquid membrane process for combined SO{sub x} and NO{sub x} removal. Final report

    SciTech Connect

    Varanasi, S.; LeBlanc, S.E.

    1992-11-01

    The lack of an efficient, cost effective process for the removal of sulfur compounds from gas streams (either gasified coal or flue gases resulting from coal combustion) is a major obstacle to the economic utilization of high sulfur Ohio coal. The most economically favorable processes for the desulfurization of flue gases are the regenerable processes as opposed to the `throwaway` processes. In addition, recovery of sulfur from these gases in the form of elemental sulfur or H{sub 2}SO{sub 4} does seem to be an essential step in the economic utilization of high sulfur coal. n light of these observations, a recently proposed FGD process which regenerates the scrubbing liquor ``in-situ`` as well as recovering a concentrated S0{sub 2} stream for use in sulfuric acid production, is quite promising. Conventional processes, presently in operation, employ large packed tower scrubbers for S0{sub 2} absorption which results in very high capital expenditures and operating costs. Recent developments in membrane technology can now provide us with an alternative to these large packed towers for stack gas cleanup. In this research we have investigated the use of novel membrane contactors for replacing more conventional packed absorbers. Contained-liquid membranes, exploiting carrier mediated transpose, enable the scrubbing liquid to be regenerated ``in-site,`` in a single process unit. Microporous single-ply polymeric membranes have recently been used in gas-liquid and liquid-liquid contactors. These membranes are fashioned into a tubular shape (i.e. long, thin fibers) for use in mass transfer contactors.

  15. Thermodynamics and dynamics of phosphatidylcholine-cholesterol mixed model membranes in the liquid crystalline state: effects of water.

    PubMed Central

    Shin, Y K; Budil, D E; Freed, J H

    1993-01-01

    A method for obtaining the thermodynamic activity of each membrane component in phosphatidylcholine (PC)/cholesterol mixtures, that is based upon ESR spin labeling is examined. The thermodynamic activity coefficients, gamma PC and gamma chol, for the PC and cholesterol, respectively, are obtained from the measured orientational order parameters, SPC and S(chol), as a function of cholesterol content for a spin-labeled PC and the sterol-type cholestane spin probe (CSL), respectively, and the effects of water concentration are also considered. At water content of 24 weight%, the thermodynamics of DMPC/cholesterol/water mixtures in the liquid-crystalline state may be treated as a two-component solution ignoring the water, but at lower water content the role of water is important, especially at lower cholesterol concentrations. At lower water content (17 wt%), gamma chol decreases with increasing cholesterol content which implies aggregation. However, at higher water content (24 wt%), gamma chol is found initially to increase as a function of cholesterol content before decreasing at higher cholesterol content. This implies a favorable accommodation for the cholesterol in the membrane at high water and low cholesterol content. Good thermodynamic consistency according to the Gibbs-Duhem equation was obtained for gamma PC and gamma chol at 24 wt% water. The availability of gamma chol (and gamma PC) as a function of cholesterol concentration permits the estimate of the boundary for phase separation. The rotational diffusion coefficients of the labeled PC and of CSL were also obtained from the ESR spectra. A previously proposed universal relation for the perpendicular component of the rotational diffusion tensor, R perpendicular, for CSL in PC/cholesterol mixtures (i.e., R perpendicular = R0 perpendicular exp(-AS2chol/RT)) is confirmed. A change in composition of cholesterol or of water for DMPC/cholesterol/water mixtures affects R perpendicular only through the dependence

  16. Why use a thermophilic aerobic membrane reactor for the treatment of industrial wastewater/liquid waste?

    PubMed

    Collivignarelli, Maria Cristina; Abbà, Alessandro; Bertanza, Giorgio

    2015-01-01

    This paper describes the advantages of thermophilic aerobic membrane reactor (TAMR) for the treatment of high strength wastewaters. The results were obtained from the monitoring of an industrial and a pilot scale plant. The average chemical oxygen demand (COD) removal yield was equal to 78% with an organic loading rate (OLR) up to 8-10 kgCOD m(-3) d(-1) despite significant scattering of the influent wastewater composition. Total phosphorus (TP) was removed with a rate of 90%, the most important removal mechanism being chemical precipitation (as hydroxyapatite, especially), which is improved by the continuous aeration that promotes phosphorus crystallization. Moreover, surfactants were removed with efficiency between 93% and 97%. Finally, the experimental work showed that thermophilic processes (TPPs) are complementary with respect to mesophilic treatments.

  17. Liquid state DNP for water accessibility measurements on spin-labeled membrane proteins at physiological temperatures

    NASA Astrophysics Data System (ADS)

    Doll, Andrin; Bordignon, Enrica; Joseph, Benesh; Tschaggelar, René; Jeschke, Gunnar

    2012-09-01

    We demonstrate the application of continuous wave dynamic nuclear polarization (DNP) at 0.35 T for site-specific water accessibility studies on spin-labeled membrane proteins at concentrations in the 10-100 μM range. The DNP effects at such low concentrations are weak and the experimentally achievable dynamic nuclear polarizations can be below the equilibrium polarization. This sensitivity problem is solved with an optimized home-built DNP probe head consisting of a dielectric microwave resonator and a saddle coil as close as possible to the sample. The performance of the probe head is demonstrated with both a modified pulsed EPR spectrometer and a dedicated CW EPR spectrometer equipped with a commercial NMR console. In comparison to a commercial pulsed ENDOR resonator, the home-built resonator has an FID detection sensitivity improvement of 2.15 and an electron spin excitation field improvement of 1.2. The reproducibility of the DNP results is tested on the water soluble maltose binding protein MalE of the ABC maltose importer, where we determine a net standard deviation of 9% in the primary DNP data in the concentration range between 10 and 100 μM. DNP parameters are measured in a spin-labeled membrane protein, namely the vitamin B12 importer BtuCD in both detergent-solubilized and reconstituted states. The data obtained in different nucleotide states in the presence and absence of binding protein BtuF reveal the applicability of this technique to qualitatively extract water accessibility changes between different conformations by the ratio of primary DNP parameters ɛ. The ɛ-ratio unveils the physiologically relevant transmembrane communication in the transporter in terms of changes in water accessibility at the cytoplasmic gate of the protein induced by both BtuF binding at the periplasmic region of the transporter and ATP binding at the cytoplasmic nucleotide binding domains.

  18. Selective Ion Transporting Polymerized Ionic Liquid Membrane Separator for Enhancing Cycle Stability and Durability in Secondary Zinc-Air Battery Systems.

    PubMed

    Hwang, Ho Jung; Chi, Won Seok; Kwon, Ohchan; Lee, Jin Goo; Kim, Jong Hak; Shul, Yong-Gun

    2016-10-05

    Rechargeable secondary zinc-air batteries with superior cyclic stability were developed using commercial polypropylene (PP) membrane coated with polymerized ionic liquid as separators. The anionic exchange polymer was synthesized copolymerizing 1-[(4-ethenylphenyl)methyl]-3-butylimidazolium hydroxide (EBIH) and butyl methacrylate (BMA) monomers by free radical polymerization for both functionality and structural integrity. The ionic liquid induced copolymer was coated on a commercially available PP membrane (Celguard 5550). The coat allows anionic transfer through the separator and minimizes the migration of zincate ions to the cathode compartment, which reduces electrolyte conductivity and may deteriorate catalytic activity by the formation of zinc oxide on the surface of the catalyst layer. Energy dispersive X-ray spectroscopy (EDS) data revealed the copolymer-coated separator showed less zinc element in the cathode, indicating lower zinc crossover through the membrane. Ion coupled plasma optical emission spectroscopy (ICP-OES) analysis confirmed over 96% of zincate ion crossover was reduced. In our charge/discharge setup, the constructed cell with the ionic liquid induced copolymer casted separator exhibited drastically improved durability as the battery life increased more than 281% compared to the pure commercial PP membrane. Electrochemical impedance spectroscopy (EIS) during the cycle process elucidated the premature failure of cells due to the zinc crossover for the untreated cell and revealed a substantial importance must be placed in zincate control.

  19. Preliminary characterization of carbon dioxide transfer in a hollow fiber membrane module as a possible solution for gas-liquid transfer in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Farges, Bérangère; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-François

    2012-01-01

    In microgravity, one of the major challenge encountered in biological life support systems (BLSS) is the gas-liquid transfer with, for instance, the necessity to provide CO2 (carbon source, pH control) and to recover the evolved O2 in photobioreactors used as atmosphere bioregenerative systems.This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module used as a possible efficient solution to the microgravity gas-liquid transfer. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient kLCO obtained in case of absorption experiments at pH 8 using the hollow fiber membrane module. The consistency of the proposed method, based on a gas and liquid phase balances verifying carbon conservation enables a very accurate determination of the kLCO value as a main limiting step of the whole process. Nevertheless, further experiments are still needed to demonstrate that the proposed method could serve in the future as reference method for mass transfer coefficient determination if using membrane modules for BLSS in reduced or microgravity conditions.

  20. Recovery of ammonia from domestic wastewater effluents as liquid fertilizers by integration of natural zeolites and hollow fibre membrane contactors.

    PubMed

    Sancho, I; Licon, E; Valderrama, C; de Arespacochaga, N; López-Palau, S; Cortina, J L

    2017-04-15

    The integration of up-concentration processes to increase the efficiency of primary sedimentation, as a solution to achieve energy neutral wastewater treatment plants, requires further post-treatment due to the missing ammonium removal stage. This study evaluated the use of zeolites as a post-treatment step, an alternative to the biological removal process. A natural granular clinoptilolite zeolite was evaluated as a sorbent media to remove low levels (up to 100mg-N/L) of ammonium from treated wastewater using batch and fixed bed columns. After being activated to the Na-form (Z-Na), the granular zeolite shown an ammonium exchange capacity of 29±0.8mgN-NH4(+)/g in single ammonium solutions and 23±0.8mgN-NH4(+)/g in treated wastewater simulating up-concentration effluent at pH=8. The equilibrium removal data were well described by the Langmuir isotherm. The ammonium adsorption into zeolites is a very fast process when compared with polymeric materials (zeolite particle diffusion coefficient around 3×10(-12)m(2)/s). Column experiments with solutions containing 100mgN-NH4(+)/L provide effective sorption and elution rates with concentration factors between 20 and 30 in consecutive operation cycles. The loaded zeolite was regenerated using 2g NaOH/L solution and the rich ammonium/ammonia concentrates 2-3g/L in NaOH were used in a liquid-liquid membrane contactor system in a closed-loop configuration with nitric and phosphoric acid as stripping solutions. The ammonia recovery ratio exceeded 98%. Ammonia nitrate and di-ammonium phosphate concentrated solutions reached up to 2-5% wt. of N.

  1. Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

    PubMed

    Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

    2015-07-14

    Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved.

  2. Preparation of two flavonoid glycosides with unique structures from barley seedlings by membrane separation technology and preparative high-performance liquid chromatography.

    PubMed

    Chen, Tao; Li, Hong-mei; Zou, Deng-Lang; Du, Yu-Zhi; Shen, Yu-Hu; Li, Yulin

    2014-12-01

    Barley seedlings are rich in flavones that can have positive effects on people with antihypoxia and antifatigue. Lutonarin and saponarin are two major flavonoid glycosides that have unique structures in barley seedlings. This study presents a new approach for the preparation of lutonarin and saponarin from barely seedlings by membrane separation technology and preparative high-performance liquid chromatography. Preparative conditions of these two flavonoid glycosides by membrane separation technology were studied using response surface methodology. Under the optimized conditions, the total contents of these two flavonoid glycosides amounts to 17.0%.

  3. Effects of polymer structure on properties of sulfonated polyimide/protic ionic liquid composite membranes for nonhumidified fuel cell applications.

    PubMed

    Yasuda, Tomohiro; Nakamura, Shin-ichiro; Honda, Yoshiyuki; Kinugawa, Kei; Lee, Seung-Yul; Watanabe, Masayoshi

    2012-03-01

    To investigate the effects of polymer structure on the properties of composite membranes including a protic ionic liquid, [dema][TfO] (diethylmethylammonium trifluoromethanesulfonate), for nonhumidified fuel cell applications, we synthesized sulfonated polyimides (SPIs) with different structures as matrix polymers, which have different magnitudes of ion-exchange capacities (IECs), different sequence distributions of ionic groups, and positions of sulfonate groups in the main chain or side chain. Despite having similar IECs, multiblock copolymer SPI and random copolymer SPI having sulfonate groups in the side chain exhibit higher ionic conductivity than random copolymer SPI having sulfonate groups in the main chain, indicating that the flexibility of sulfonic acid groups and the sequence distribution of ionic groups greatly affect the ion conduction. Atomic force microscopy observation revealed that the multiblock copolymer SPI forms more developed phase separation than the others. These results indicate that the flexibility of sulfonic acid groups and the connectivity of the ion conduction channel, which greatly depends on the sequence distribution, affect the ion conduction.

  4. Comprehensive one-dimensional, semi-analytical, mathematical model for liquid-feed polymer electrolyte membrane direct methanol fuel cells

    NASA Astrophysics Data System (ADS)

    Kareemulla, D.; Jayanti, S.

    Polymer electrolyte membrane direct methanol fuel cells (PEM-DMFCs) have several advantages over hydrogen-fuelled PEM fuel cells; but sluggish methanol electrochemical oxidation and methanol crossover from the anode to the cathode through the PEM are two major problems with these cells. In the present work, a comprehensive one-dimensional, single phase, isothermal mathematical model is developed for a liquid-feed PEM-DMFC, taking into account all the necessary mass transport and electrochemical phenomena. Diffusion and convective effects are considered for methanol transport on the anode side and in the PEM, whereas only diffusional transport of species is considered on the cathode side. A multi-step reaction mechanism is used to describe the electrochemical oxidation of methanol at the anode. Stefan-Maxwell equations are used to describe multi-component diffusion on the cathode side and Tafel type of kinetics is used to describe the simultaneous methanol oxidation and oxygen reduction reactions at the cathode. The model fully accounts for the mixed potential effect caused by methanol crossover at the cathode. It shows excellent agreement with literature data of the limiting current density for different low methanol feed concentrations at different operating temperatures. At high methanol feed concentrations, oxygen depletion on the cathode side, due to excessive methanol crossover, results in mass-transport limitations. The model can be used to optimize the geometric and physical parameters with a view to extracting the highest current density while still keeping a tolerably low methanol crossover.

  5. Supported liquid membrane-protected molecularly imprinted beads for micro-solid phase extraction of sulfonamides in environmental waters.

    PubMed

    Díaz-Álvarez, M; Barahona, F; Turiel, E; Martín-Esteban, A

    2014-08-29

    In this work, molecularly imprinted polymer (MIP) beads have been prepared and evaluated for the development of a supported liquid membrane-protected micro-solid phase extraction method for the analysis of sulfonamides (SAs) in aqueous samples. The performance of MIP beads was firstly evaluated in cartridges by conventional solid-phase extraction for the simultaneous analysis of SAs. Afterward, beads were packed into a polypropylene hollow fiber protected by an organic solvent immobilized in the pores of the capillary wall. During the process, the analytes were extracted from the aqueous sample to the immobilized organic solvent and then selectively retained by the MIP beads located inside the capillary. The effect of various experimental parameters as sample pH, time and stirring-rate among others, were studied for the establishment of optimum rebinding conditions. Relative recoveries for all sulfonamides tested in river and reservoir water samples by the proposed method using 100mL water sample spiked with 50μg L-1 of each sulfonamide were within 70-120%, with a relative standard deviation (RSD) <10% (n=3). The detection limits (LODs) were within 0.2-3μgL(-1), depending upon the sulfonamide and the type of water used.

  6. Membrane supported liquid-liquid-liquid microextraction combined with field-amplified sample injection CE-UV for high-sensitivity analysis of six cardiovascular drugs in human urine sample.

    PubMed

    Zhou, Xiaoqing; He, Man; Chen, Beibei; Yang, Qing; Hu, Bin

    2016-05-01

    An effective dual preconcentration method involving off-line membrane supported liquid-liquid-liquid microextraction (MS-LLLME) and on-line field-amplified sample injection (FASI) was proposed for the extraction of six cardiovascular drugs, including mexiletine, xylocaine, propafenone, propranolol, metoprolol, and carvedilol from aqueous solution prior to CE-UV. In MS-LLLME, the analytes were extracted from 9 mL sample solution into toluene, and then back extracted into a drop of acceptor phase of 10 μL 20 mmol/L acetic acid. After that, the acceptor phase was directly introduced into CE for FASI without any modification. In FASI process, water plug was hydrodynamically injected (50 mbar, 3 s) into the capillary prior to sample injection (+6 kV, 18 s). Six target analytes were separated in less than 10 min at 25°C with a BGE consisting of 70 mmol/L Tris-H3 PO4 (pH 2.2) containing 10% v/v methanol. Under the optimized conditions, LODs obtained by the proposed MS-LLLME-FASI-CE-UV method were in the range of 0.02-0.82 μg/L (based on S/N = 3) with enrichment factors of 546- to 7300-fold for the target analytes. The RSDs of the developed method were in the range of 6.7-12.9% (n = 7). Good linearity (R(2) = 0.9928-0.9997) was obtained in concentration range of 0.1-100 μg/L for mexiletine and propranolol, 0.2-100 μg/L for xylocaine and metoprolol, 0.5-100 μg/L for propafenone and 2.0-100 μg/L for carvedilol, respectively. The developed method was successfully applied for real-time determination of metoprolol in human urine samples within 26 h after uptake.

  7. Ionic liquid-impregnated agarose film two-phase micro-electrodriven membrane extraction (IL-AF-μ-EME) for the analysis of antidepressants in water samples.

    PubMed

    Mohamad Hanapi, Nor Suhaila; Sanagi, Mohd Marsin; Ismail, Abd Khamim; Wan Ibrahim, Wan Aini; Saim, Nor'ashikin; Wan Ibrahim, Wan Nazihah

    2017-03-01

    The aim of this study was to investigate and apply supported ionic liquid membrane (SILM) in two-phase micro-electrodriven membrane extraction combined with high performance liquid chromatography-ultraviolet detection (HPLC-UV) for pre-concentration and determination of three selected antidepressant drugs in water samples. A thin agarose film impregnated with 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM] [PF6], was prepared and used as supported ionic liquid membrane between aqueous sample solution and acceptor phase for extraction of imipramine, amitriptyline and chlorpromazine. Under the optimized extraction conditions, the method provided good linearity in the range of 1.0-1000μgL(-1), good coefficients of determination (r(2)=0.9974-0.9992) and low limits of detection (0.1-0.4μgL(-1)). The method showed high enrichment factors in the range of 110-150 and high relative recoveries in the range of 88.2-111.4% and 90.9-107.0%, for river water and tap water samples, respectively with RSDs of ≤7.6 (n=3). This method was successfully applied to the determination of the drugs in river and tap water samples. It is envisaged that the SILM improved the perm-selectivity by providing a pathway for targeted analytes which resulted in rapid extraction with high degree of selectivity and high enrichment factor.

  8. Separation of CO{sub 2} from CO{sub 2}/N{sub 2} mixture using supported polymeric liquid membranes at elevated temperatures

    SciTech Connect

    Jeong, S.H.; Lee, K.H.

    1999-09-01

    Novel supported polymeric liquid (SPL) membranes have been prepared and shown to be applicable for the separation of CO{sub 2} from mixtures with N{sub 2} at the elevated temperature encountered in flue gas. The membranes were fabricated by immobilizing polystyrene, polyethylene, and polydimethylsiloxane into the pores of borosilicate glass supports. At 250 C, the CO{sub 2} permeability and CO{sub 2}/N{sub 2} separation factors were 3000--9000 barrer and 1.7--3.7, respectively. It was shown that polymers which have a lower T{sub g} or melting temperature than the operating temperature can be used as SPL membrane materials at elevated temperatures.

  9. Novel amphiphilic polymeric ionic liquid-solid phase micro-extraction membrane for the preconcentration of aniline as degradation product of azo dye Orange G under sonication by liquid chromatography-tandem mass spectrometry.

    PubMed

    Cai, Mei-Qiang; Wei, Xiao-Qing; Du, Chun-Hui; Ma, Xu-Ming; Jin, Mi-Cong

    2014-07-04

    A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76μgμg(-1) for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0μgL(-1) with a correlation coefficient value of 0.9998. The limit of quantification was 0.5μgL(-1). The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution.

  10. A bulk liquid membrane-flow injection (BLM-FI) coupled system for the preconcentration and determination of vanadium in saline waters.

    PubMed

    Pinto, Juan J; García-Vargas, Manuel; Moreno, Carlos

    2013-01-15

    A bulk liquid membrane-flow injection (BLM-FI) system has been developed for the preconcentration and spectrophotometric determination of vanadium in saline waters. The preconcentration step was based on a bulk liquid membrane containing Aliquat 336 (acting as a carrier) dissolved in dodecane/dodecanol. Vanadium species were chemically pumped due to the pH gradient between the sample (pH 3.2) and the receiving solution (pH 9.8). Vanadium transport through the membrane was monitored by a new and sensitive spectrophotometric method based on its reaction with di-2-pyridyl ketone benzoylhydrazone (dPKBH) in an acidic medium. As a consequence of membrane transport, vanadium was recovered in an ammonium solution, where total vanadium concentration was spectrophotometrically determined at 375 nm, as the pentavalent species, by using a flow injection analysis (FIA) system. Under optimal conditions, this FIA system provided a detection limit of 4.7 μg L(-1) (3s(blank)/m) and RSD 2.72%, for vanadium determination in saline samples. Both preconcentration and determination steps were previously optimized by modified simplex methodologies. The proposed coupled method was successfully applied to the determination of vanadium in a certified reference material (TMDA-62) and in two seawater samples.

  11. Development of a new three-phase membrane-assisted liquid-phase microextraction method: determination of nitrite in tap water samples as model analytical application.

    PubMed

    Pedrón, Isabel; Chisvert, Alberto; March, Juan G; Salvador, Amparo; Benedé, Juan L

    2011-04-01

    A novel and simple device for membrane-assisted liquid-phase microextraction is used for the first time in a three-phase system. The device consists of a glass vial containing the aqueous acceptor phase, whose septum of its screw stopper has been replaced by a sized piece of polytetrafluoroethylene membrane impregnated with n-decane. The vial is assembled to a volumetric flask containing the aqueous donor phase, and the membrane comes in contact alternatively with both donor and acceptor aqueous phases by orbital agitation. The device has been tested for the determination of nitrite in tap water samples, which is extensively carried out in routine analysis, as model analytical application. Experimental variables, such as the organic solvent used to form the supported liquid membrane, the volumes of both donor and acceptor phases, the orbital agitation rate, and the extraction time were studied and optimized in terms of enrichment factor. Under the selected working conditions, the analytical figures of merit for nitrite determination were a linearity range up to 50 ng mL(-1), limits of detection and quantification of 0.15 and 0.50 ng mL(-1), respectively, and a good repeatability (RSD < 10%). The method has been applied to four tap water samples of different origins, and accurate and precise results were achieved. Besides, the very low volume of organic solvent used, its low cost and the no-risk of cross-contamination are significant operational advantages.

  12. Capillary high-performance liquid chromatography/mass spectrometric analysis of proteins from affinity-purified plasma membrane.

    PubMed

    Zhao, Yingxin; Zhang, Wei; White, Michael A; Zhao, Yingming

    2003-08-01

    Proteomics analysis of plasma membranes is a potentially powerful strategy for the discovery of proteins involved in membrane remodeling under diverse cellular environments and identification of disease-specific membrane markers. A key factor for successful analysis is the preparation of plasma membrane fractions with low contamination from subcellular organelles. Here we report the characterization of plasma membrane prepared by an affinity-purification method, which involves biotinylation of cell-surface proteins and subsequent affinity enrichment with strepavidin beads. Western blotting analysis showed this method was able to achieve a 1600-fold relative enrichment of plasma membrane versus mitochondria and a 400-fold relative enrichment versus endoplasmic reticulum, two major contaminants in plasma membrane fractions prepared by conventional ultracentrifugation methods. Capillary-HPLC/MS analysis of 30 microg of affinity-purified plasma membrane proteins led to the identification of 918 unique proteins, which include 16.4% integral plasma membrane proteins and 45.5% cytosol proteins (including 8.6% membrane-associated proteins). Notable among the identified membrane proteins include 30 members of ras superfamily, receptors (e.g., EGF receptor, integrins), and signaling molecules. The low number of endoplasmic reticulum and mitochondria proteins (approximately 3.3% of the total) suggests the plasma membrane preparation has minimum contamination from these organelles. Given the importance of integral membrane proteins for drug design and membrane-associated proteins in the regulation cellular behaviors, the described approach will help expedite the characterization of plasma membrane subproteomes, identify signaling molecules, and discover therapeutic membrane-protein targets in diseases.

  13. Simultaneous micro-electromembrane extractions of anions and cations using multiple free liquid membranes and acceptor solutions.

    PubMed

    Kubáň, Pavel; Boček, Petr

    2016-02-18

    Micro-electromembrane extractions (μ-EMEs) across free liquid membranes (FLMs) were applied to simultaneous extractions of anions and cations. A transparent narrow-bore polymeric tubing was filled with adjacent plugs of μL volumes of aqueous and organic solutions, which formed a stable five-phase μ-EME system. For the simultaneous μ-EMEs of anions and cations, aqueous donor solution was the central phase, which was sandwiched between two organic FLMs and two aqueous acceptor solutions. On application of electric potential, anions and cations in the donor solution migrated across the two FLMs and into the two peripheral acceptor solutions in the direction of anode and cathode, respectively. Visual monitoring of anionic (tartrazine) and cationic (phenosafranine) dye confirmed their simultaneous μ-EMEs and their rapid (in less than 5 min) transfers into anolyte and catholyte, respectively. The concept of simultaneous μ-EMEs was further examined with selected model analytes; KClO4 was used for μ-EMEs of inorganic anions and cations and ibuprofen and procaine for μ-EMEs of acidic and basic drugs. Quantitative analyses of the resulting acceptor solutions were carried out by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4)D). Good extraction recoveries (91-94%) and repeatability of peak areas (≤6.3%) were achieved for 5 min μ-EMEs of K(+) and ClO4(-). Extraction recoveries and repeatability of peak areas for 5 min μ-EMEs of ibuprofen and procaine were also satisfactory and ranged from 35 to 63% and 7.6 to 11.3%, respectively. Suitability of the presented micro-extraction procedure was further demonstrated on simultaneous μ-EMEs with subsequent CE-C(4)D of ibuprofen and procaine from undiluted human urine samples.

  14. Impact of membrane-induced particle immobilization on seeded growth monitored by in situ liquid scanning transmission electron microscopy

    DOE PAGES

    Weiner, Rebecca G.; Chen, Dennis P.; Unocic, Raymond R.; ...

    2016-04-01

    In situ liquid cell scanning transmission electron microscopy probes seeded growth in real time. The growth of Pd on Au nanocubes is monitored as a model system to compare growth within a liquid cell and traditional colloidal synthesis. Furthermore, different growth patterns are observed due to seed immobilization and the highly reducing environment within the liquid cell.

  15. Impact of Membrane-Induced Particle Immobilization on Seeded Growth Monitored by In Situ Liquid Scanning Transmission Electron Microscopy.

    PubMed

    Weiner, Rebecca G; Chen, Dennis P; Unocic, Raymond R; Skrabalak, Sara E

    2016-05-01

    In situ liquid cell scanning transmission electron microscopy probes seeded growth in real time. The growth of Pd on Au nanocubes is monitored as a model system to compare growth within a liquid cell and traditional colloidal synthesis. Different growth patterns are observed due to seed immobilization and the highly reducing environment within the liquid cell.

  16. Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation.

    PubMed

    Casado-Coterillo, Clara; Del Mar López-Guerrero, María; Irabien, Angel

    2014-06-19

    Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO2 solubility of the polymer, and, thus, the CO2 affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO2 selective MMMs from renewable or green chemistry materials.

  17. Thermal stability, complexing behavior, and ionic transport of polymeric gel membranes based on polymer PVdF-HFP and ionic liquid, [BMIM][BF4].

    PubMed

    Shalu; Chaurasia, S K; Singh, R K; Chandra, S

    2013-01-24

    PVdF-HFP + IL(1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF(4)]) polymeric gel membranes containing different amounts of ionic liquid have been synthesized and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared (FTIR), differential scanning calorimetry, thermogravimetric analysis (TGA), and complex impedance spectroscopic techniques. Incorporation of IL in PVdF-HFP polymer changes different physicochemical properties such as melting temperature (T(m)), thermal stability, structural morphology, amorphicity, and ionic transport. It is shown by FTIR, TGA (also first derivative of TGA, "DTGA") that IL partly complexes with the polymer PVdF-HFP and partly remains dispersed in the matrix. The ionic conductivity of polymeric gel membranes has been found to increase with increasing concentration of IL and attains a maximum value of 1.6 × 10(-2) S·cm(-1) for polymer gel membrane containing 90 wt % IL at room temperature. Interestingly, the values of conductivity of membranes with 80 and 90 wt % of IL were higher than that of pure IL (100 wt %). The polymer chain breathing model has been suggested to explain it. The variation of ionic conductivity with temperature of these gel polymeric membranes follows Arrhenius type thermally activated behavior.

  18. Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation

    PubMed Central

    Casado-Coterillo, Clara; López-Guerrero, María del Mar; Irabien, Ángel

    2014-01-01

    Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO2 solubility of the polymer, and, thus, the CO2 affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO2 selective MMMs from renewable or green chemistry materials. PMID:24957178

  19. Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

    PubMed

    Kim, Yushin; Amemiya, Shigeru

    2008-08-01

    A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

  20. A model for self-sustained potential oscillation of lipid bilayer membranes induced by the gel-liquid crystal phase transitions.

    PubMed

    Yagisawa, K; Naito, M; Gondaira, K I; Kambara, T

    1993-05-01

    To clarify the mechanism of self-sustained oscillation of the electric potential between the two solutions divided by a lipid bilayer membrane, a microscopic model of the membrane system is presented. It is assumed, on the basis of the observed results (Yoshikawa, K., T. Omachi, T. Ishii, Y. Kuroda, and K. liyama. 1985. Biochem. Biophys. Res. Commun. 133:740-744; Ishii, T., Y. Kuroda, T. Omochi, and K. Yoshikawa. 1986. Langmuir. 2:319-321; Toko, K., N. Nagashima, S. liyama, K. Yamafuji, and T. Kunitake. Chem. Lett. 1986:1375-1378), that the gel-liquid crystal phase transition of the membrane drives the potential oscillation. It is studied, by using the model, how and under what condition the repetitive phase transition may occur and induce the potential oscillation. The transitions are driven by the repetitive adsorption and desorption of proton by the membrane surface, actions that are induced the periodic reversal of the direction of protonic current. The essential conditions for the periodic reversal are (a) at least one kind of cations such as Na+ or K+ are included in the system except for proton, and the variation of their permeability across the membrane due to the phase transition is noticeably larger than that of proton permeability; and (b) the phase transition has a hysteresis. When these conditions are fulfilled, the self-sustained potential oscillation may be brought about by adjusting temperature, pH, and the cation concentration in the solutions on both sides of the membrane. Application of electric current across the membrane also induces or modifies the potential oscillation. Periodic, quasiperiodic, and chaotic oscillations appear especially, depending on the value of frequency of the applied alternating current.

  1. Automation of static and dynamic non-dispersive liquid phase microextraction. Part 2: Approaches based on impregnated membranes and porous supports.

    PubMed

    Alexovič, Michal; Horstkotte, Burkhard; Solich, Petr; Sabo, Ján

    2016-02-11

    A critical overview on automation of modern liquid phase microextraction (LPME) approaches based on the liquid impregnation of porous sorbents and membranes is presented. It is the continuation of part 1, in which non-dispersive LPME techniques based on the use of the extraction phase (EP) in the form of drop, plug, film, or microflow have been surveyed. Compared to the approaches described in part 1, porous materials provide an improved support for the EP. Simultaneously they allow to enlarge its contact surface and to reduce the risk of loss by incident flow or by components of surrounding matrix. Solvent-impregnated membranes or hollow fibres are further ideally suited for analyte extraction with simultaneous or subsequent back-extraction. Their use can therefore improve the procedure robustness and reproducibility as well as it "opens the door" to the new operation modes and fields of application. However, additional work and time are required for membrane replacement and renewed impregnation. Automation of porous support-based and membrane-based approaches plays an important role in the achievement of better reliability, rapidness, and reproducibility compared to manual assays. Automated renewal of the extraction solvent and coupling of sample pretreatment with the detection instrumentation can be named as examples. The different LPME methodologies using impregnated membranes and porous supports for the extraction phase and the different strategies of their automation, and their analytical applications are comprehensively described and discussed in this part. Finally, an outlook on future demands and perspectives of LPME techniques from both parts as a promising area in the field of sample pretreatment is given.

  2. Large-area graphene-based nanofiltration membranes by shear alignment of discotic nematic liquid crystals of graphene oxide

    NASA Astrophysics Data System (ADS)

    Akbari, Abozar; Sheath, Phillip; Martin, Samuel T.; Shinde, Dhanraj B.; Shaibani, Mahdokht; Banerjee, Parama Chakraborty; Tkacz, Rachel; Bhattacharyya, Dibakar; Majumder, Mainak

    2016-03-01

    Graphene-based membranes demonstrating ultrafast water transport, precise molecular sieving of gas and solvated molecules shows great promise as novel separation platforms; however, scale-up of these membranes to large-areas remains an unresolved problem. Here we demonstrate that the discotic nematic phase of graphene oxide (GO) can be shear aligned to form highly ordered, continuous, thin films of multi-layered GO on a support membrane by an industrially adaptable method to produce large-area membranes (13 × 14 cm2) in <5 s. Pressure driven transport data demonstrate high retention (>90%) for charged and uncharged organic probe molecules with a hydrated radius above 5 Å as well as modest (30-40%) retention of monovalent and divalent salts. The highly ordered graphene sheets in the plane of the membrane make organized channels and enhance the permeability (71+/-5 l m-2 hr-1 bar-1 for 150+/-15 nm thick membranes).

  3. Energy efficient membrane processes for the separation of organic liquids: Part 3 (Supplement report): Final report, September 28, 1982--December 31, 1986

    SciTech Connect

    Cabasso, I.; Acharya, H.R.; Korngold, E.; Liu, Z.; Stern, S.A.; Li, W.; Makenzie, T.; Poda, E.

    1987-10-01

    In this supplemental report, two pilot plants are described. The first is air purge pervaporation (or air sweep pervaporation hollow fiber system) for the separation of azeotropic aqueous liquids. The second describes pilot plant construction and operation for the perstraction process. Several configurations for the air purge pervaporation process were studied and were shown to yield high purity products e.g., isopropanol from the azeotropic mixture with water was enriched to 99.9%. Parallel and U-module configuration were used and durability experiments up to 120 days were carried out successfully. The report describes the first successful low scale pilot plant unit and elements for perstraction process. The conclusion and outcome of this study are two fold. First, membrane systems in a pilot plant unit proved to be very efficient in upgrading nonpermeable components in a membrane system and especially when dealing with azeotropic mixtures. For example, more than 99% isopropanol can be produced from a feed liquid which is 88% i-PrOH (azeotropic mixture with water). The membrane system proved to be durable within the time limit of the experiments (120 days). Second, all parameters including the various configurations of the pilot plants (which are still being studied) are available for chemical, petroleum, and other US industries. 3 refs., 22 figs., 2 tabs.

  4. Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

    PubMed

    Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

    2015-02-01

    Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation.

  5. Determination of pesticide residues in wine by membrane-assisted solvent extraction and high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Moeder, M; Bauer, C; Popp, P; van Pinxteren, M; Reemtsma, T

    2012-06-01

    The determination of pesticides in food products is an essential issue to guarantee food safety and minimise health risks of consumers. A protocol based on membrane-assisted solvent extraction and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) that allows the determination of 18 pesticides in red wine at minimum labour effort for sample preparation was developed and validated. Ten millilitres of wine were extracted using 100 μL of toluene filled in a non-porous polyethylene membrane bag which is immersed in the wine sample. After 150 min extraction under stirring, an aliquot of the extraction solution is analysed using HPLC-MS/MS. The limits of quantification ranged from 3 ng/L for Pirimicarb to 1.33 μg/L for Imidacloprid. Quantification by matrix-matched calibration provided relative standard deviations ≤16 % for most of the target pesticides. The linearity of calibration was given over three to four orders of magnitude, which enables the reliable measurement of a broad range of pesticide concentrations, and for each target pesticide, the sensitivity of the protocol meets the maximum residue levels set by legislations at least for wine grapes. Good agreement of results was found when the new method was compared with a standard liquid-liquid extraction protocol. In five wine samples analysed, Carbendazim and Metalaxyl were determined at micrograms per litre concentrations, even in some of the organic wines. Tebuconazol and Cyprodinitril were determined at lower abundance and concentration, followed by Spiroxamin and Diuron.

  6. Energy efficient membrane processes for the separation of organic liquids: Part 2: Final report, September 28, 1982--December 31, 1986

    SciTech Connect

    Cabasso, I.; Acharya, H.R.; Korngold, E.; Liu, Z.; Stern, S.A.; Li, W.; Makenzie, T.; Poda, E.

    1987-10-01

    The present report demonstrates the use of membrane technology for dehydration processes concentrating on two examples: azeotropic separation of isopropanol-water, and separation of ethanol-water mixtures (starting at 84.5 wt. % ethanol where separation by distillation begins to be progressively more energy intensive). The principles of the membrane separation processes employed in such separations were discussed in Part I of the report. The advantage of the membrane processes is that they do not require the addition of a third component and separation is a continuous process. Pervaporation, perstraction, and air-sweep pervaporation were thoroughly studied for these separations. An urgent need for the identification of the appropriate membrane was realized. This study has revealed that ion-exchange membranes are suited for these separations. Results are discussed. 9 refs., 68 figs., 33 tabs.

  7. Di(2-ethylhexyl)phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater.

    PubMed

    Venkateswaran, P; Navaneetha Gopalakrishnan, A; Palanivelu, K

    2007-01-01

    Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconut oil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 x 10(-9) to 8.9 x 10(-9) mol/(m2 x s) within the Cu(II) concentration range 7.8 x 10(-4)-78.6 x 10(-4) mol/L at pH of 4.0 in the feed and 12.4 x 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 x 10(-9) mol/(m2 x s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 x 10(-4) mol/L D2EHPA (membrane) in 0.5 microm pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II).

  8. Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle.

    PubMed

    Đorđević, Jelena; Vladisavljević, Goran T; Trtić-Petrović, Tatjana

    2017-01-01

    A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P ≥ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

  9. Sustainable Process for the Preparation of High-Performance Thin-Film Composite Membranes using Ionic Liquids as the Reaction Medium.

    PubMed

    Mariën, Hanne; Bellings, Lotte; Hermans, Sanne; Vankelecom, Ivo F J

    2016-05-23

    A new form of interfacial polymerization to synthesize thin-film composite membranes realizes a more sustainable membrane preparation and improved nanofiltration performance. By introducing an ionic liquid (IL) as the organic reaction phase, the extremely different physicochemical properties to those of commonly used organic solvents influenced the top-layer formation in several beneficial ways. In addition to the elimination of hazardous solvents in the preparation, the m-phenylenediamine (MPD) concentration could be reduced 20-fold, and the use of surfactants and catalysts became redundant. Together with the more complete recycling of the organic phase in the water/IL system, these factors resulted in a 50 % decrease in the mass intensity of the top-layer formation. Moreover, a much thinner top layer with a high ethanol permeance of 0.61 L m(-2)  h(-1)  bar(-1) [99 % Rose Bengal (RB, 1017 Da) retention; 1 bar=0.1 MPa] was formed without the use of any additives. This EtOH permeance is 555 and 161 % higher than that for the conventional interfacial polymerization (without and with additives, respectively). In reverse osmosis, high NaCl retentions of 97 % could be obtained. Finally, the remarkable decrease in the membrane surface roughness indicates the potential for reduced fouling with this new type of membrane.

  10. STED microscopy detects and quantifies liquid phase separation in lipid membranes using a new far-red emitting fluorescent phosphoglycerolipid analogue.

    PubMed

    Honigmann, Alf; Mueller, Veronika; Hell, Stefan W; Eggeling, Christian

    2013-01-01

    We have developed a bright, photostable, and far-red emitting fluorescent phosphoglycerolipid analogue to probe diffusion characteristics of lipids in membranes. The lipid analogue consists of a saturated (C18) phosphoethanolamine and a hydrophilic far-red emitting fluorescent dye (KK114) that is tethered to the head group by a long polyethylenglycol linker. In contrast to reported far-red emitting fluorescent lipid analogues, this one partitions predominantly into liquid ordered domains of phase-separated ternary bilayers. We performed fluorescence correlation spectroscopy with a super-resolution STED microscope (STED-FCS) to measure the lateral diffusion of the new lipid analogue in the liquid ordered (Lo) and disordered (Ld) phase. On a mica support, we observed micrometer large phases and found that the lipid analogue diffuses freely on all tested spatial scales (40-250 nm) in both the Ld and Lo phase with diffusion coefficients of 1.8 microm2 s(-1) and 0.7 microm2 s(-1) respectively. This indicates that the tight molecular packing of the Lo phase mainly slows down the diffusion rather than causing anomalous sub-diffusion. The same ternary mixture deposited on acid-cleaned glass forms Lo nanodomains of < 40 nm to 300 nm in diameter as only revealed by STED microscopy, which demonstrates the severe influence of interactions with the substrate on the sizes of domains in membranes. When averaging over different positions, STEd-FCS measurements on such glass supported membranes displayed anomalous sub-diffusion. This anomaly can be attributed to a transient partitioning of the lipid analogue into the nano-domains, where diffusion is slowed down. Our results suggest that STED-FCS in combination with a Lo-partitioning fluorescent lipid analogue can directly probe the presence of Lo nano-domains, which in the future should allow the study of potential lipid rafts in live-cell membranes.

  11. DETERMINATION OF IN VITRO AND IN SILICO INDEXES FOR THE MODELLING OF BLOOD-BRAIN BARRIER PARTITIONING OF DRUGS VIA MICELLAR AND IMMOBILIZED ARTIFICIAL MEMBRANE LIQUID CHROMATOGRAPHY.

    PubMed

    Russo, Giacomo; Grumetto, Lucia; Szucs, Roman; Barbato, Francesco; Lynen, Frederic

    2017-04-11

    In the present work, 79 structurally unrelated analytes were taken into account and their chromatographic retention coefficients, measured by Immobilized Artificial Membrane Liquid Chromatography (IAM-LC), and by Micellar Liquid Chromatography (MLC) employing sodium dodecyl sulfate (SDS) as surfactant, were determined. Such indexes were subsequently used for the development of Blood-Brain Barrier passage-predictive statistical models using partial least square (PLS) regression along with topological and physico-chemical parameters, calculated in silico. Highly significant relationships were observed either using IAM (r2 (n-1) = 0.78) or MLC (r2 (n-1) = 0.83) derived indexes along with in silico descriptors. This hybrid approach proved fast and effective in the development of highly predictive BBB passage oriented models and, therefore, it can be of interest for pharmaceutical industries as a high-throughput BBB penetration oriented screening method. Finally, it offered interesting insights into the molecular mechanism actually involved in the BBB permeation of drugs.

  12. In vitro effects of l-carnitine and glutamine on motility, acrosomal abnormality, and plasma membrane integrity of rabbit sperm during liquid-storage.

    PubMed

    Sarıözkan, Serpil; Ozdamar, Saim; Türk, Gaffari; Cantürk, Fazile; Yay, Arzu

    2014-06-01

    This study was designed to evaluate the in vitro effects of l-carnitine and glutamine (Gln) on the sperm quality parameters of liquid-stored rabbit semen maintained up to 24 h at 5°C. Pooled and extended ejaculates were divided into two equal portions. l-Carnitine doses of 0.5, 1 and 2mM were added to the first portion, and glutamine was added at the same doses to the second portion. All samples were cooled to 5°C and examined at 0, 6, 12 and 24 h of liquid storage. Supplementation of the semen extender with three different doses of l-carnitine provided significant increases in the percentage of motile sperm at 12 h (P<0.01), and 24h (P<0.001) and enabled significant protection of the sperm plasma membrane (P<0.01) at 12 and 24h of cool-storage, in comparison to the control samples. Only the 2mM dose of l-carnitine significantly (P<0.01) decreased the rate of acrosomal damage when compared to the control group. Furthermore, all doses of Gln caused a significant (P<0.01) decrease in acrosomal damage at 6h, and provided significant improvement (P<0.01) in sperm motility, acrosomal and plasma membrane integrities at 12 and 24h of liquid storage, when compared to the controls. In conclusion, the supplementation of liquid-stored rabbit semen with l-carnitine and Gln provided a protection for sperm against cool storage-induced functional and structural damages.

  13. Membrane selectivity in pervaporation

    SciTech Connect

    Kujawski, W.

    1996-06-01

    A qualitative description is presented of pervaporation which discusses the initial preferential sorption into the membrane, diffusion of liquid, phase transition from liquid to vapor phase, followed by diffusion of vapors and fast desorption from the other side of the membrane. The overall separation of each pervaporation step was calculated in terms of separation factor {alpha}. The results show that in the case of hydrophilic membranes (i.e., dense polyamide-6 membrane and ion-exchange membrane PESS-1) and water-ethanol mixtures, the phase transition step decreases the overall separation. Also, diffusion through the membrane is unfavorable to water at a low concentration range.

  14. Large-area graphene-based nanofiltration membranes by shear alignment of discotic nematic liquid crystals of graphene oxide

    PubMed Central

    Akbari, Abozar; Sheath, Phillip; Martin, Samuel T.; Shinde, Dhanraj B.; Shaibani, Mahdokht; Banerjee, Parama Chakraborty; Tkacz, Rachel; Bhattacharyya, Dibakar; Majumder, Mainak

    2016-01-01

    Graphene-based membranes demonstrating ultrafast water transport, precise molecular sieving of gas and solvated molecules shows great promise as novel separation platforms; however, scale-up of these membranes to large-areas remains an unresolved problem. Here we demonstrate that the discotic nematic phase of graphene oxide (GO) can be shear aligned to form highly ordered, continuous, thin films of multi-layered GO on a support membrane by an industrially adaptable method to produce large-area membranes (13 × 14 cm2) in <5 s. Pressure driven transport data demonstrate high retention (>90%) for charged and uncharged organic probe molecules with a hydrated radius above 5 Å as well as modest (30–40%) retention of monovalent and divalent salts. The highly ordered graphene sheets in the plane of the membrane make organized channels and enhance the permeability (71±5 l m−2 hr−1 bar−1 for 150±15 nm thick membranes). PMID:26947916

  15. Novel ceramic-polymer composite membranes for the separation of hazardous liquid waste. 1998 annual progress report

    SciTech Connect

    Cohen, Y.

    1998-06-01

    'This report summarizes the work progress over the last 1.75 years of a 3 year project. The objectives of the project have been to develop a new class of ceramic-supported polymeric membranes that could be tailored-designed for a wide-range of applications in remediation and pollution prevention. To date, a new class of chemically-modified ceramic membranes was developed for the treatment of oil-in-water emulsions and for the pervaporation removal of volatile organics from aqueous systems. These new ceramic-supported polymer (CSP) membranes are fabricated by modifying the pore surface of a ceramic membrane support by a graft polymerization process (Chaimberg and Cohen, 1994). The graft polymerization process consists of activating the membrane surface with alkoxy vinyl silanes onto which vinyl monomers are added via free-radical graft polymerization resulting in a thin surface layer of terminally anchored polymer chains. Reaction conditions are selected based on knowledge of the graft polymerization kinetics for the specific polymer/substrate system. The resultant ceramic-supported polymer (CSP) membrane is a composite structure in which mechanical strength is provided by the ceramic support and the selectivity is determined by the covalently bonded polymer brush layer. Thus, one of the unique attributes of the CSP membrane is that it can be used in environments where the polymer layer is swollen (or even completely miscible) in the mixture to be separated (Castro et al., 1993). It is important to note that the above modification process is carried out under mild conditions (e.g., temperature of about 70 C) and is well suited for large scale commercial application. In a series of studies, the applicability of a polyvinylpyrrolidone CSP membrane was demonstrated for the treatment of oil-in-water emulsion under a variety of flow conditions (Castro et al.,1996). Improved membrane performance was achieved due to minimization of surface adsorption of the oil components

  16. Voltammetric heparin-selective electrode based on thin liquid membrane with conducting polymer-modified solid support.

    PubMed

    Guo, Jidong; Amemiya, Shigeru

    2006-10-01

    A novel, solid-supported voltammetric ion-selective electrode to detect anticoagulant/antithrombotic heparin at polarizable poly(vinyl chloride) (PVC) membrane/water interfaces was developed. An approximately 3-4.5-microm-thick PVC membrane plasticized with 2-nitrophenyl octyl ether was supported on a gold electrode modified with a poly(3-octylthiophene) (POT) film as an ion-to-electron transducer. Charge transport through the PVC-covered POT film is electrochemically reversible, as demonstrated by cyclic voltammetry with nonpolarizable membrane/water interfaces. In addition to the fast charge transport, adequate redox capacity of the POT film and a small ohmic potential drop in the thin PVC membrane enable ion transfer voltammetry at polarizable macroscopic membrane/water interfaces in a standard three-electrode cell. Reversible ClO4- transfer at the interfaces coupled with oxidation of a neutral POT film was examined by cyclic voltammetry to determine the distribution of the applied potential to the two polarizable interfaces by convolution technique. Interfacial adsorption and desorption of heparin facilitated by octadecyltrimethylammonium were studied also by cyclic voltammetry and convolution technique to demonstrate that the processes are electrochemically irreversible. Stripping voltammetry based on the interfacial processes gives a low detection limit of 0.005 unit/mL heparin in a saline solution, which is slightly lower than the detection limit of most sensitive heparin sensors reported so far (0.01 unit/mL).

  17. Inkjet printing of nanoporous gold electrode arrays on cellulose membranes for high-sensitive paper-like electrochemical oxygen sensors using ionic liquid electrolytes.

    PubMed

    Hu, Chengguo; Bai, Xiaoyun; Wang, Yingkai; Jin, Wei; Zhang, Xuan; Hu, Shengshui

    2012-04-17

    A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

  18. Energy efficient membrane processes for the separation of organic liquids: Part 1: Final report, September 28, 1982--December 31, 1986

    SciTech Connect

    Cabasso, I.; Acharya, H.R.; Korngold, E.; Liu, Z.; Stern, S.A.; Li, W.; Makenzie, T.; Poda, E.

    1987-10-01

    The potential usefulness of two membrane processes, namely, pervaporation and perstraction, for separating azeotropic mixtures of aromatic and aliphatic hydrocarbons was studied theoretically and experimentally. A third membrane process, osmotic phase-separation, was investigated experimentally. The separation of an azeotropic mixture of benzene and cyclohexane was used as an example. Part II of this report will discuss membrane processes for the separation of alcohol/water mixtures. Mathematical models of pervaporation and perstraction were developed for computer simulations of the processes. The perstraction model presented herein is the first of its kind. Additionally, the energy requirements and capital investments costs for the separation of an azeotropic benzene/cyclohexane mixture were determined and compared with those for extractive distillation. 31 refs., 64 figs., 19 tabs.

  19. Engineering Development of Ceramic Membrane Reactor System for Converting Natural Gas to Hydrogen and Synthesis Gas for Liquid Transportation Fuels

    SciTech Connect

    Air Products and Chemicals

    2008-09-30

    An Air Products-led team successfully developed ITM Syngas technology from the concept stage to a stage where a small-scale engineering prototype was about to be built. This technology produces syngas, a gas containing carbon monoxide and hydrogen, by reacting feed gas, primarily methane and steam, with oxygen that is supplied through an ion transport membrane. An ion transport membrane operates at high temperature and oxygen ions are transported through the dense membrane's crystal lattice when an oxygen partial pressure driving force is applied. This development effort solved many significant technical challenges and successfully scaled-up key aspects of the technology to prototype scale. Throughout the project life, the technology showed significant economic benefits over conventional technologies. While there are still on-going technical challenges to overcome, the progress made under the DOE-funded development project proved that the technology was viable and continued development post the DOE agreement would be warranted.

  20. Liquid—liquid interface-mediated Au—ZnO composite membrane using ‘thiol-ene’ click chemistry

    NASA Astrophysics Data System (ADS)

    Ali, Mohammed; Ghosh, Sujit Kumar

    2015-07-01

    A nanoparticle-decorated composite membrane has been devised at the water/CCl4 interface based on the self-assembly of ligand-stabilized gold and zinc oxide nanoparticles, exploiting the ‘thiol-ene’ click chemistry between the thiol groups of 11-mercaptoundecanoic acid-stabilized ZnO nanoparticles and the ene functionality of cinnamic acid attached to gold nanoparticles. The interfacial assembly of ultrasmall particles leads to a multilayer film that exhibits charge-dependent permeability of amino acid molecules across the membrane.

  1. Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid.

    PubMed

    Bahrami, Abdulrahman; Ghamari, Farhad; Yamini, Yadollah; Ghorbani Shahna, Farshid; Moghimbeigi, Abbas

    2017-02-12

    This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L(-1) sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL(-1) were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%-8.2% and 4.1%-10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens.

  2. Theoretical and experimental correlations of gas dissolution, diffusion, and thermodynamic properties in determination of gas permeability and selectivity in supported ionic liquid membranes.

    PubMed

    Gan, Quan; Zou, Yiran; Rooney, David; Nancarrow, Paul; Thompson, Jillian; Liang, Lizhe; Lewis, Moira

    2011-05-11

    Supported ionic liquid membranes (SILMs) has the potential to be a new technological platform for gas/organic vapour separation because of the unique non-volatile nature and discriminating gas dissolution properties of room temperature ionic liquids (ILs). This work starts with an examination of gas dissolution and transport properties in bulk imidazulium cation based ionic liquids [C(n)mim][NTf2] (n=2.4, 6, 8.10) from simple gas H(2), N(2), to polar CO(2), and C(2)H(6), leading to a further analysis of how gas dissolution and diffusion are influenced by molecular specific gas-SILMs interactions, reflected by differences in gas dissolution enthalpy and entropy. These effects were elucidated again during gas permeation studies by examining how changes in these properties and molecular specific interactions work together to cause deviations from conventional solution-diffusion theory and their impact on some remarkably contrasting gas perm-selectivity performance. The experimental perm-selectivity for all tested gases showed varied and contrasting deviation from the solution-diffusion, depending on specific gas-IL combinations. It transpires permeation for simpler non-polar gases (H(2), N(2)) is diffusion controlled, but strong molecular specific gas-ILs interactions led to a different permeation and selectivity performance for C(2)H(6) and CO(2). With exothermic dissolution enthalpy and large order disruptive entropy, C(2)H(6) displayed the fastest permeation rate at increased gas phase pressure in spite of its smallest diffusivity among the tested gases. The C(2)H(6) gas molecules "peg" on the side alkyl chain on the imidazulium cation at low concentration, and are well dispersed in the ionic liquids phase at high concentration. On the other hand strong CO(2)-ILs affinity resulted in a more prolonged "residence time" for the gas molecule, typified by reversed CO(2)/N(2) selectivity and slowest CO(2) transport despite CO(2) possess the highest solubility and

  3. Membrane damage and active but nonculturable state in liquid cultures of Escherichia coli treated with an atmospheric pressure plasma jet.

    PubMed

    Dolezalova, Eva; Lukes, Petr

    2015-06-01

    Electrical discharge plasmas can efficiently inactivate various microorganisms. Inactivation mechanisms caused by plasma, however, are not fully understood because of the complexity of both the plasma and biological systems. We investigated plasma-induced inactivation of Escherichia coli in water and mechanisms by which plasma affects bacterial cell membrane integrity. Atmospheric pressure argon plasma jet generated at ambient air in direct contact with bacterial suspension was used as a plasma source. We determined significantly lower counts of E. coli after treatment by plasma when they were assayed using a conventional cultivation technique than using a fluorescence-based LIVE/DEAD staining method, which indicated that bacteria may have entered the viable-but-nonculturable state (VBNC). We did not achieve resuscitation of these non-culturable cells, however, we detected their metabolic activity through the analysis of cellular mRNA, which suggests that cells may have been rather in the active-but-nonculturable state (ABNC). We hypothesize that peroxidation of cell membrane lipids by the reactive species produced by plasma was an important pathway of bacterial inactivation. Amount of malondialdehyde and membrane permeability of E. coli to propidium iodide increased with increasing bacterial inactivation by plasma. Membrane damage was also demonstrated by detection of free DNA in plasma-treated water.

  4. Ion transfer across a liquid membrane. General solution for the current-potential response of any voltammetric technique.

    PubMed

    Molina, A; Serna, C; Gonzalez, J; Ortuño, J A; Torralba, E

    2009-02-28

    An explicit analytical equation applicable to the study of reversible ion transfer at systems with two liquid/liquid polarizable interfaces is presented. This expression is valid for any multipotential step technique, which are all very adequate for the determination of standard transfer potentials and transport parameters of ions. The expression of the I/E response for linear sweep voltammetry and cyclic voltammetry can also be deduced as a particular case of this equation. The general solution given here is formally similar to that obtained for the application of any multipotential step sequence to a system with a single polarizable interface, since the method followed here is based on the same premises.

  5. Novel macrocyclic carriers for proton-coupled liquid membrane transport. Progress report, December 1, 1992--November 30, 1993

    SciTech Connect

    Lamb, J.D.; Bradshaw, J.S.; Shirts, R.B.; Izatt, R.M.

    1993-08-01

    Methods were devised for preparing cryptands (bicyclic ligands). Effects of addition of hydrophobic side chains on crown ethers used in separation systems; crowns containing side chains of varying lengths were studied in back extraction and dual module hollow fiber membrane separation experiments. Thermodynamics of macrocycle-cation reactions were studied at high temperature. Effort was made on computer (molecular mechanics) modeling of macrocycle binding of alkali metal ions in gas phase. 8 figs, 26 refs.

  6. Simultaneous determination of ampicillin and sulbactam by liquid chromatography: post-column reaction with sodium hydroxide and sodium hypochlorite using an active hollow-fibre membrane reactor.

    PubMed

    Haginaka, J; Nishimura, Y

    1990-10-26

    A high-performance liquid chromatographic method has been developed for the simultaneous determination of ampicillin (ABPC) and sulbactam (SBT) in serum and urine. The method involves separation of ABPC and SBT from the background components of serum and urine on a C18 column, post-column reaction with sodium hydroxide and sodium hypochlorite using an active hollow-fibre membrane reactor, and detection at 270 nm. At ABPC and SBT concentrations of 10 and 5 micrograms/ml in urine and serum samples, the precisions (relative standard deviations) were 0.9-2.5% (n = 8). The detection limits were 20 and 5 ng for ABPC and SBT, respectively, at a signal-to-noise ratio of 3.

  7. Permeation of mixtures of four phenols through a supported liquid membrane in NaCl 1.0 mol/dm{sup 3} medium

    SciTech Connect

    Arana, G.; Borge, G.; Etxebarria, N.; Fernandez, L.A.

    1999-02-01

    The permeation of four phenols (phenol, 2-chlorophenol, 2-nitrophenol, and 2,4-dichlorophenol) through a supported liquid membrane has been studied in NaCl 1.0 mol/dm{sup 3} medium. The flux of each phenol was determined by measuring in real time the change of their concentration in the strip phase by making use of a fiber optic spectrophotometer and a multivariate calibration. The model for the permeation of phenol alone was first developed by making permeation experiments of a phenol, and then permeation studies of the mixture were carried out and the model was extended to those phenols. It was found that the permeation of a phenol is interfered with by the presence of other phenols.

  8. Electro membrane extraction of sodium diclofenac as an acidic compound from wastewater, urine, bovine milk, and plasma samples and quantification by high-performance liquid chromatography.

    PubMed

    Davarani, Saied Saeed Hosseiny; Pourahadi, Ahmad; Nojavan, Saeed; Banitaba, Mohammad Hossein; Nasiri-Aghdam, Mahnaz

    2012-04-13

    Electro membrane extraction (EME) as a new microextraction method was applied for extraction of sodium diclofenac (SDF) as an acidic compound from wastewater, urine, bovine milk and plasma samples. Under applied potential of 20 V during the extraction, SDF migrated from a 2.1 mL of sample solution (1mM NaOH), through a supported liquid membrane (SLM), into a 30 μL acceptor solution (10 mM NaOH), exist inside the lumen of the hollow fiber. The negative electrode was placed in the donor solution, and the positive electrode was placed in the acceptor solution. 1-octanol was immobilized in the pores of a porous hollow fiber of polypropylene as SLM. Then the extract was analyzed by means of high-performance liquid chromatography (HPLC) with UV-detection for quantification of SDF. Best results were obtained using a phosphate running electrolyte (10 mM, pH 2.5). The ranges of quantitation for different samples were 8-500 ngmL(-1). Intra- and inter-day RSDs were less than 14.5%. Under the optimized conditions, the preconcentration factors were between 31 and 66 and also the limit of detections (LODs) ranged from 2.7 ng mL(-1) to 5 ng mL(-1) in different samples. This procedure was applied to determine SDF in wastewater, bovine milk, urine and plasma samples (spiked and real samples). Extraction recoveries for different samples were between 44-95% after 5 min of extraction.

  9. An enhanced plant lipidomics method based on multiplexed liquid chromatography-mass spectrometry reveals additional insights into cold- and drought-induced membrane remodeling.

    PubMed

    Tarazona, Pablo; Feussner, Kirstin; Feussner, Ivo

    2015-11-01

    Within the lipidome of plants a few bulk molecular species hamper the detection of the rest, which are present at relatively low levels. In addition, low-abundance species are often masked by numerous isobaric interferences, such as those caused by isoelemental species and isotopologues. This scenario not only means that minor species are underrepresented, but also leads to potential misidentifications and limits the structural information gathered by lipidomics approaches. In order to overcome these limitations we have developed a multiplexed liquid chromatography-mass spectrometry lipidomics platform able to achieve an enhanced coverage of plant lipidomes. The platform is based on a single extraction step followed by a series of ultra-performance liquid chromatography separations. Post-column flow is then directed to both a triple quadrupole analyzer for targeted profiling and a time-of-flight analyzer for accurate mass analysis. As a proof of concept, plants were subjected to cold or drought, which are known to trigger widespread remodeling events in plant cell membranes. Analysis of the leaf lipidome yielded 393 molecular species within 23 different lipid classes. This enhanced coverage allowed us to identify lipid molecular species and even classes that are altered upon stress, allowing hypotheses on role of glycosylinositolphosphoceramides (GIPC), steryl glycosides (SG) and acylated steryl glycosides (ASG) in drought stress to be addressed and confirming the findings from numerous previous studies with a single, wide-ranging lipidomics approach. This extended our knowledge on membrane remodeling during the drought response, integrating sphingolipids and sterol lipids into the current glycerolipid-based model.

  10. Analysis of liquid water formation in polymer electrolyte membrane (PEM) fuel cell flow fields with a dry cathode supply

    NASA Astrophysics Data System (ADS)

    Gößling, Sönke; Klages, Merle; Haußmann, Jan; Beckhaus, Peter; Messerschmidt, Matthias; Arlt, Tobias; Kardjilov, Nikolay; Manke, Ingo; Scholta, Joachim; Heinzel, Angelika

    2016-02-01

    PEM fuel cells can be operated within a wide range of different operating conditions. In this paper, the special case of operating a PEM fuel cell with a dry cathode supply and without external humidification of the cathode, is considered. A deeper understanding of the water management in the cells is essential for choosing the optimal operation strategy for a specific system. In this study a theoretical model is presented which aims to predict the location in the flow field at which liquid water forms at the cathode. It is validated with neutron images of a PEM fuel cell visualizing the locations at which liquid water forms in the fuel cell flow field channels. It is shown that the inclusion of the GDL diffusion resistance in the model is essential to describe the liquid water formation process inside the fuel cell. Good agreement of model predictions and measurement results has been achieved. While the model has been developed and validated especially for the operation with a dry cathode supply, the model is also applicable to fuel cells with a humidified cathode stream.

  11. Liquid-phase non-thermal plasma-prepared N-doped TiO(2) for azo dye degradation with the catalyst separation system by ceramic membranes.

    PubMed

    Cheng, Hsu-Hui; Chen, Shiao-Shing; Cheng, Yi-Wen; Tseng, Wei-Lun; Wang, Yi-Hui

    2010-01-01

    This study strived to improve the photocatalytic activity by using liquid-phase non-thermal plasma (LPNTP) technology for preparing N-doping TiO(2) as well as to separate/recover the N-dope TiO(2) particles by using ceramic ultrafiltration membrane process. The yellow color N-doped TiO(2) photocatalysts, obtained through the LPNTP process, were characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysis (ESCA). The UV-Vis spectrum of N-doped TiO(2) showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectra showed that the peak positions and the crystal structure remained unchanged as anatase after plasma-treating at 13.5 W for 40 min. The photocatalytic activity of N-doped TiO(2) was evaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours in a continuous-flow photocatalytic system. For membrane separation/recover system, the recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min, and the result indicated that the photocatalyst was able to be separated/recovered completely.

  12. Acid effect on 99mTc and 99Mo mutual separation and their transport across supported liquid membrane extraction system

    NASA Astrophysics Data System (ADS)

    Ashraf Chaudry, M.

    2000-02-01

    Work on 99mTc extraction using supported liquid membrane (SLM) has been performed with tri-n-octylamine as a carrier. MoO 4 2- ions transport with TOA-xylene has alos been studied with respect to HCl concentration (0.001 to 0.05M) in the feed solution. 99mTc transport in the same HCl concentration range has shown that while MoO 4 2- ions flux is higher at -5mol/m2.s, the TcO 4 - ions flux is in the range of (5-7)×10-11 mol/m2.s. In case of sulphuric acid in the feed the transport of 99mTc has been found to be higher ((28-55)×10-11 mol/m2), while 99Mo transport is observed to be suppressed as the H2SO4 concentration in the feed solution increases, providing a useful method for extraction of 99mTc, produced from the disintegration of 99Mo with time. Membranes supports used are of polypropylene and PTFE material. Effect of acid on Mo species present in the feed solution and the mechanism of transport through the SLM are also discussed.

  13. Cr(VI) transport via a supported ionic liquid membrane containing CYPHOS IL101 as carrier: system analysis and optimization through experimental design strategies.

    PubMed

    Rodríguez de San Miguel, Eduardo; Vital, Xóchitl; de Gyves, Josefina

    2014-05-30

    Chromium(VI) transport through a supported liquid membrane (SLM) system containing the commercial ionic liquid CYPHOS IL101 as carrier was studied. A reducing stripping phase was used as a mean to increase recovery and to simultaneously transform Cr(VI) into a less toxic residue for disposal or reuse. General functions which describe the time-depending evolution of the metal fractions in the cell compartments were defined and used in data evaluation. An experimental design strategy, using factorial and central-composite design matrices, was applied to assess the influence of the extractant, NaOH and citrate concentrations in the different phases, while a desirability function scheme allowed the synchronized optimization of depletion and recovery of the analyte. The mechanism for chromium permeation was analyzed and discussed to contribute to the understanding of the transfer process. The influence of metal concentration was evaluated as well. The presence of different interfering ions (Ca(2+), Al(3+), NO3(-), SO4(2-), and Cl(-)) at several Cr(VI): interfering ion ratios was studied through the use of a Plackett and Burman experimental design matrix. Under optimized conditions 90% of recovery was obtained from a feed solution containing 7mgL(-1) of Cr(VI) in 0.01moldm(-3) HCl medium after 5h of pertraction.

  14. Electrokinetic extraction on artificial liquid membranes of amphetamine-type stimulants from urine samples followed by high performance liquid chromatography analysis.

    PubMed

    Seidi, Shahram; Yamini, Yadollah; Baheri, Tahmineh; Feizbakhsh, Rouhollah

    2011-07-01

    Electromembrane extraction (EME) coupled with high performance liquid chromatography and ultraviolet detection was developed for determination of amphetamine-type stimulants in human urine samples. Amphetamines migrated from 3 mL of different human urine matrices, through a thin layer of 2-nitrophenyl octyl ether (NPOE) containing 15% tris-(2-ethylhexyl) phosphate (TEHP) immobilized in the pores of a porous hollow fiber, and into a 15 μL acidic aqueous acceptor solution present inside the lumen of the fiber. Equilibrium extraction conditions were obtained after 7 min of operation. Experimental design and response surface methodology (RSM) were used for optimization of EME parameters. Under optimal conditions, amphetamines were effectively extracted with recoveries in the range of 54-70%, which corresponded to preconcentration factors in the range of 108-140. The calibration curves were investigated in the range of 0-7 μg mL(-1) and good linearity was achieved with a coefficient of estimation better than 0.991. Detection limits and inter-day precision (n=3) were less than 0.01 μg mL(-1) and 11.2%, respectively.

  15. Ultrafast photoinduced charge separation in naphthalene diimide based multichromophoric systems in liquid solutions and in a lipid membrane.

    PubMed

    Banerji, Natalie; Fürstenberg, Alexandre; Bhosale, Sheshanath; Sisson, Adam L; Sakai, Naomi; Matile, Stefan; Vauthey, Eric

    2008-07-31

    The photophysical properties of multichromophoric systems consisting of eight red or blue naphthalene diimides (NDIs) covalently attached to a p-octiphenyl scaffold, as well as a blue bichromophoric system with a biphenyl scaffold, have been investigated in detail using femtosecond time-resolved spectroscopy. The blue octachromophoric systems have been recently shown to self-assemble as supramolecular tetramers in lipid bilayer membranes and to enable generation of a transmembrane proton gradient upon photoexcitation ( Bhosale, S. ; Sisson, A. L. ; Talukdar, P. ; Fürstenberg, A. ; Banerji, N. ; Vauthey, E. ; Bollot, G. ; Mareda, J. ; Röger, C. ; Würthner, F. ; Sakai, N. ; Matile, S. Science 2006, 313, 84 ). A strong reduction of the fluorescence quantum yield was observed when going from the single NDI units to the multichromophoric systems in methanol, the effect being even stronger in a vesicular lipid membrane. Fluorescence up-conversion measurements reveal ultrafast self-quenching in the multichromophoric systems, whereas the formation of the NDI radical anion, evidenced by transient absorption measurements, points to the occurrence of photoinduced charge separation. The location of the positive charge could not be established unambiguously from the transient absorption measurements, but energetic considerations indicate that charge separation should occur between two NDI units in the blue systems, whereas both an NDI unit and the p-octiphenyl scaffold could act as electron donor in the red system. The lifetime of the charge-separated state was found to increase from 22 to 45 ps by going from the bi- to the octachromophoric blue systems in methanol, while a 400 ps decay component was observed in the lipid membrane. This lifetime lengthening is explained in terms of charge migration that is most efficient when the octachromophoric systems are assembled as supramolecular tetramers in the lipid membrane. Furthermore, the average charge-separated state lifetime

  16. Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid

    PubMed Central

    Bahrami, Abdulrahman; Ghamari, Farhad; Yamini, Yadollah; Ghorbani Shahna, Farshid; Moghimbeigi, Abbas

    2017-01-01

    This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L−1 sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL−1 were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%–8.2% and 4.1%–10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens. PMID:28208685

  17. IMIDAZOLE-BASED IONIC LIQUIDS FOR USE IN POLYMER ELECTROLYTE MEMBRANE FUEL CELLS: EFFECT OF ELECTRON-WITHDRAWING AND ELECTRON-DONATING SUBSTITUENTS

    SciTech Connect

    Chang, E.; Fu, Y.; Kerr, J.

    2009-01-01

    Current polymer electrolyte membrane fuel cells (PEMFCs) require humidifi cation for acceptable proton conductivity. Development of a novel polymer that is conductive without a water-based proton carrier is desirable for use in automobiles. Imidazole (Im) is a possible replacement for water as a proton solvent; Im can be tethered to the polymer structure by means of covalent bonds, thereby providing a solid state proton conducting membrane where the solvating groups do not leach out of the fuel cell. These covalent bonds can alter the electron availability of the Im molecule. This study investigates the effects of electron-withdrawing and electron-donating substituents on the conductivity of Im complexed with methanesulfonic acid (MSA) in the form of ionic liquids. Due to the changes in the electronegativity of nitrogen, it is expected that 2-phenylimidazole (2-PhIm, electron-withdrawing) will exhibit increased conductivity compared to Im, while 2-methylimidazole (2-MeIm, electron-donating) will exhibit decreased conductivity. Three sets of ionic liquids were prepared at defi ned molar ratios: Im-MSA, 2-PhIm-MSA, and 2-MeIm- MSA. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and 1H-NMR were used to characterize each complex. Impedance analysis was used to determine the conductivity of each complex. Both the 2-PhIm-MSA and 2-MeIm-MSA ionic liquids were found to be less conductive than the Im-MSA complex at base-rich compositions, but more conductive at acid-rich compositions. 1H-NMR data shows a downfi eld shift of the proton on nitrogen in 2-PhIm compared to Im, suggesting that other factors may diminish the electronic effects of the electron withdrawing group at base-rich compositions. Further studies examining these effects may well result in increased conductivity for Im-based complexes. Understanding the conductive properties of Im-derivatives due to electronic effects will help facilitate the development of a new electrolyte

  18. Liquid-liquid extraction and flat sheet supported liquid membrane studies on Am(III) and Eu(III) separation using 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine as the extractant.

    PubMed

    Bhattacharyya, A; Mohapatra, P K; Gadly, T; Raut, D R; Ghosh, S K; Manchanda, V K

    2011-11-15

    Solvent extraction and supported liquid membrane transport studies for the preferential removal of Am(3+) from feeds containing a mixture of Am(3+) and Eu(3+) was carried out using 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (n-Pr-BTP) as the extractant. Diluent plays an important role in these studies. It was observed that the distribution coefficients deteriorate significantly for both Am(3+) and Eu(3+) though the separation factors were affected only marginally. The transport studies were carried out at pH 2.0 in the presence of NaNO(3) to result in the preferential Am(3+) transport with high separation factors. Effect of different experimental parameters, viz. feed composition, stripping agents, diluents of the organic liquid membrane and membrane pore size was studied on the transport and separation behaviour of Am(3+) and Eu(3+). The supported liquid membrane studies indicated about 85% Am(3+) and 6% Eu(3+) transport in 6h using 0.03 M n-Pr-BTP in n-dodecane/1-octanol (7:3) diluent mixture for a feed containing 1M NaNO(3) at pH 2 and a receiver phase containing pH 2 solution as the strippant. Consequently, a permeability coefficient of (1.75 ± 0.21) × 10(-4)cms(-1) was determined for the Am(3+) transport. Stability of the n-Pr-BTP and its SLM was also studied by carrying out the distribution and transport experiment after different time intervals.

  19. Rotating bubble membrane radiator

    DOEpatents

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  20. Polymer membrane based electrolytic cell and process for the direct generation of hydrogen peroxide in liquid streams

    NASA Technical Reports Server (NTRS)

    White, James H. (Inventor); Schwartz, Michael (Inventor); Sammells, Anthony F. (Inventor)

    1997-01-01

    An electrolytic cell for generating hydrogen peroxide is provided including a cathode containing a catalyst for the reduction of oxygen, and an anode containing a catalyst for the oxidation of water. A polymer membrane, semipermeable to either protons or hydroxide ions is also included and has a first face interfacing to the cathode and a second face interfacing to the anode so that when a stream of water containing dissolved oxygen or oxygen bubbles is passed over the cathode and a stream of water is passed over the anode, and an electric current is passed between the anode and the cathode, hydrogen peroxide is generated at the cathode and oxygen is generated at the anode.

  1. Separation of alkali, alkaline earth and rare earth cations by liquid membranes containing macrocyclic carriers. Third progress report, September 1, 1980-April 1, 1981

    SciTech Connect

    Christensen, J.J.

    1981-04-15

    The overall objective of this project is to study the use of liquid membrane systems employing macrocyclic ligand carriers in making separations among metal cations. During the third year of the project, work continued in the development of a mathematical model to describe cation transport. The model was originally developed to describe the relationship between cation transport rate (J/sub M/) and the cation-macrocycle stability constant (K). The model was tested by determining the rates of transport of alkali and alkaline earth cations through chloroform membranes containing carrier ligands where the stability constants for their reaction with cations in methanol were known. From the results, it is clear that the model correctly describes the dependence of J/sub M/ on log K. The model also correctly describes the effect of cation concentration and carrier concentration on cation transport rates, as detailed in the previous progress report. During the third year of the project, the transport model was expanded so as to apply to competitive transport of cations from mixtures of two cations in the source aqueous phase. Data were collected under these conditions and the ability of the model to predict the flux of each cation was tested. Representative data of this type are presented along with corresponding data which were obtained when each cation was transported by the same carrier from a source phase containing only that cation. Comparison of transport rates determined under the two experimental conditions indicates that the relationship between the two sets of data is complex. To date, a few of these data involving transport from binary cation mixtures have been tested against the transport model. It was found that the model correctly predicts the cation fluxes from cation mixtures. These preliminary results indicate that the transport model can successfully predict separation factors when cation mixtures are used.

  2. Liquid metal electric pump

    DOEpatents

    Abbin, Joseph P.; Andraka, Charles E.; Lukens, Laurance L.; Moreno, James B.

    1992-01-01

    An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other.

  3. A comparison of bacterial populations in enhanced biological phosphorus removal processes using membrane filtration or gravity sedimentation for solids-liquid separation.

    PubMed

    Hall, Eric R; Monti, Alessandro; Mohn, William W

    2010-05-01

    CEBPR system also revealed many uncultured organisms that have not been well characterized. The study demonstrated that a simple replacement of a secondary clarifier with membrane solids-liquid separation is sufficient to shift the composition of an activated sludge microbial community significantly.

  4. Ion Exchange and Antibiofouling Properties of Poly(ether sulfone) Membranes Prepared by the Surface Immobilization of Brønsted Acidic Ionic Liquids via Double-Click Reactions.

    PubMed

    Yi, Zhuan; Liu, Cui-Jing; Zhu, Li-Ping; Xu, You-Yi

    2015-07-28

    Brønsted acidic ionic liquids (BAILs) are unique ionic liquids that display chemical structures similar to zwitterions, and they were typically used as solvents and catalysts. In this work, an imidazole-based BAIL monolayer was fabricated onto poly(ether sulfone) (PES) membranes via surface clicking reactions, and the multifunctionality, including ion exchange and biofouling resistance to proteins and bacteria, was demonstrated, which was believed to be one of few works in which BAIL had been considered to be a novel fouling resistance layer for porous membranes. The successful immobilization of the BAILs onto a membrane surface was confirmed by X-ray photoelectron spectroscopy analysis, contact angle measurement, and ζ potential determination. The results from Raman spectroscopy showed that, as a decisive step prior to zwitterion, the BAIL was deprotonated in aqueous solution, and biofouling resistance to proteins and bacteria was found. However, BAIL displayed ion exchange ability at lower pH, and surface hydrophilicity/hydrophobicity of membranes could be tuned on purpose. Our results have demonstrated that the BAIL grafted onto membranes will not only act as an antibiofouling barrier like zwitterions but also provide a platform for surface chemical tailoring by ion exchange, the property of which will become especially important in acidic solutions where the fouling resistance performances of zwitterions are greatly weakened.

  5. Biomimetic membranes and methods of making biomimetic membranes

    DOEpatents

    Rempe, Susan; Brinker, Jeffrey C.; Rogers, David Michael; Jiang, Ying-Bing; Yang, Shaorong

    2016-11-08

    The present disclosure is directed to biomimetic membranes and methods of manufacturing such membranes that include structural features that mimic the structures of cellular membrane channels and produce membrane designs capable of high selectivity and high permeability or adsorptivity. The membrane structure, material and chemistry can be selected to perform liquid separations, gas separation and capture, ion transport and adsorption for a variety of applications.

  6. Effectiveness and humidification capacity investigation of liquid-to-air membrane energy exchanger under low heat capacity ratios at winter air conditions

    NASA Astrophysics Data System (ADS)

    Kassai, Miklos

    2015-06-01

    In this research, a novel small-scale single-panel liquid-to-air membrane energy exchanger has been used to numerically investigate the effect of given number of heat transfer units (4.5), different cold inlet air temperature (1.7, 5.0, 10.0 °C) and different low heat capacity ratio (0.4, 0.5, 0.6, 0.7, 0.8, 0.9) on the steady-state performance of the energy exchanger. This small-scale energy exchanger represents the full-scale prototypes well, saving manufacturing costs and time. Lithium chloride is used as a salt solution in the system and the steady-state total effectiveness of the exchanger is evaluated for winter inlet air conditions. The results show that total effectiveness of the energy exchanger decreases with heat capacity ratio in the mentioned range. Maximum numerical total effectiveness of 97% is achieved for the energy exchanger. Increasing the heat capacity ratio values on given inlet air temperature, the humidification capacity of energy exhanger is also investigated in this paper. The humidification performance increases with heat capacity ratio. The highest humidification performance (4.53 g/kg) can be reached when inlet air temperature is 1.7 °C, and heat capacity ratio is 1.0 in winter inlet air conditions in the range of low heat capacity ratio.

  7. Histamine H1 receptor cell membrane chromatography online high-performance liquid chromatography with mass spectrometry method reveals houttuyfonate as an activator of the histamine H1 receptor.

    PubMed

    Guo, Ying; Han, Shengli; Cao, Jingjing; Zhang, Tao; He, Langchong

    2014-11-01

    Allergy is an abnormal reaction of the body to an allergen. Histamine is responsible for many of the acute symptoms of allergic diseases. Many of the allergic and inflammatory actions of histamine are mediated by the histamine H1 receptor. In the present study, we established a two-dimensional histamine H1 receptor/cell membrane chromatography with online high-performance liquid chromatography and mass spectrometry method for screening potential histamine-activating components in a traditional Chinese medicine injection. The specification of the method was validated by screening, separating, and identifying a mixed standard solution of diphenhydramine hydrochloride, gefitinib, tamsulosin, and nitrendipine. The Yujin injection, an example of traditional Chinese medicine injection, was screened and potential allergic components acting on the histamine H1 receptor were identified. A Ca(2+) flux assay showed that houttuyfonate and Yujin injection induced calcium release in a dose-dependent manner. This suggests that houttuyfonate is an activator of the histamine H1 receptor. The mechanism of houttuyfonate activation involves phosphorylation of the inositol-1,4,5-trisphosphate receptor. In conclusion, this two-dimensional method can rapidly detect and enrich target components isolated from the Yujin injection. This indicates that individuals with an overexpression of the histamine H1 receptor should be aware of possible allergic reactions when receiving the Yujin injection.

  8. X-ray Reflectivity Study of the Interaction of an Imidazolium-Based Ionic Liquid with a Soft Supported Lipid Membrane.

    PubMed

    Bhattacharya, G; Giri, R P; Saxena, H; Agrawal, V V; Gupta, A; Mukhopadhyay, M K; Ghosh, S K

    2017-02-07

    Ionic liquids (ILs) are important for their antimicrobial activity and are found to be toxic to some microorganisms. To shed light on the mechanism of their activities, the interaction of an imidazolium-based IL 1-butyl-3-methylimidazolium tetrfluoroborate ([BMIM][BF4]) with E. coli bacteria and cell-membrane-mimicking lipid mono- and bilayers has been studied. The survival of the bacteria and corresponding growth inhibition are observed to be functions of the concentration of the IL. The IL alters the pressure-area isotherm of the monolayer formed at an air-water interface by the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid. The in-plane elasticity of the lipid layer is reduced as a consequence of the insertion of this IL. The X-ray reflectivity study from a polymer-supported lipid bilayer shows strong perturbation in the self-assembled structure of the bilayer due to the interaction. As a consequence, there is a considerable decrease in bilayer thickness and a corresponding increase in electron density. These results, however, depend on the chain configurations of the lipid molecules.

  9. Supported inorganic membranes

    DOEpatents

    Sehgal, Rakesh; Brinker, Charles Jeffrey

    1998-01-01

    Supported inorganic membranes capable of molecular sieving, and methods for their production, are provided. The subject membranes exhibit high flux and high selectivity. The subject membranes are substantially defect free and less than about 100 nm thick. The pores of the subject membranes have an average critical pore radius of less than about 5 .ANG., and have a narrow pore size distribution. The subject membranes are prepared by coating a porous substrate with a polymeric sol, preferably under conditions of low relative pressure of the liquid constituents of the sol. The coated substrate is dried and calcined to produce the subject supported membrane. Also provided are methods of derivatizing the surface of supported inorganic membranes with metal alkoxides. The subject membranes find use in a variety of applications, such as the separation of constituents of gaseous streams, as catalysts and catalyst supports, and the like.

  10. Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Almlie, Jay C.

    2010-01-01

    A water membrane evaporator (WME) has been conceived and tested as an alternative to the contamination-sensitive and corrosion-prone evaporators currently used for dissipating heat from space vehicles. The WME consists mainly of the following components: An outer stainless-steel screen that provides structural support for the components mentioned next; Inside and in contact with the stainless-steel screen, a hydrophobic membrane that is permeable to water vapor; Inside and in contact with the hydrophobic membrane, a hydrophilic membrane that transports the liquid feedwater to the inner surface of the hydrophobic membrane; Inside and in contact with the hydrophilic membrane, an annular array of tubes through which flows the spacecraft coolant carrying the heat to be dissipated; and An inner exclusion tube that limits the volume of feedwater in the WME. In operation, a pressurized feedwater reservoir is connected to the volume between the exclusion tube and the coolant tubes. Feedwater fills the volume, saturates the hydrophilic membrane, and is retained by the hydrophobic membrane. The outside of the WME is exposed to space vacuum. Heat from the spacecraft coolant is conducted through the tube walls and the water-saturated hydrophilic membrane to the liquid/vapor interface at the hydrophobic membrane, causing water to evaporate to space. Makeup water flows into the hydrophilic membrane through gaps between the coolant tubes.

  11. Full subunit coverage liquid chromatography electrospray ionization mass spectrometry (LCMS+) of an oligomeric membrane protein: cytochrome b(6)f complex from spinach and the cyanobacterium Mastigocladus laminosus.

    PubMed

    Whitelegge, Julian P; Zhang, Huamin; Aguilera, Rodrigo; Taylor, Ross M; Cramer, William A

    2002-10-01

    Highly active cytochrome b(6)f complexes from spinach and the cyanobacterium Mastigocladus laminosus have been analyzed by liquid chromatography with electrospray ionization mass spectrometry (LCMS+). Both size-exclusion and reverse-phase separations were used to separate protein subunits allowing measurement of their molecular masses to an accuracy exceeding 0.01% (+/-3 Da at 30,000 Da). The products of petA, petB, petC, petD, petG, petL, petM, and petN were detected in complexes from both spinach and M. laminosus, while the spinach complex also contained ferredoxin-NADP(+) oxidoreductase (Zhang, H., Whitelegge, J. P., and Cramer, W. A. (2001) Flavonucleotide:ferredoxin reductase is a subunit of the plant cytochrome b(6)f complex. J. Biol. Chem. 276, 38159-38165). While the measured masses of PetC and PetD (18935.8 and 17311.8 Da, respectively) from spinach are consistent with the published primary structure, the measured masses of cytochrome f (31934.7 Da, PetA) and cytochrome b (24886.9 Da, PetB) modestly deviate from values calculated based upon genomic sequence and known post-translational modifications. The low molecular weight protein subunits have been sequenced using tandem mass spectrometry (MSMS) without prior cleavage. Sequences derived from the MSMS spectra of these intact membrane proteins in the range of 3.2-4.2 kDa were compared with translations of genomic DNA sequence where available. Products of the spinach chloroplast genome, PetG, PetL, and PetN, all retained their initiating formylmethionine, while the nuclear encoded PetM was cleaved after import from the cytoplasm. While the sequences of PetG and PetN revealed no discrepancy with translations of the spinach chloroplast genome, Phe was detected at position 2 of PetL. The spinach chloroplast genome reports a codon for Ser at position 2 implying the presence of a DNA sequencing error or a previously undiscovered RNA editing event. Clearly, complete annotation of genomic data requires detailed

  12. Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

    PubMed Central

    Otvagina, Ksenia V.; Mochalova, Alla E.; Sazanova, Tatyana S.; Petukhov, Anton N.; Moskvichev, Alexandr A.; Vorotyntsev, Andrey V.; Afonso, Carlos A. M.; Vorotyntsev, Ilya V.

    2016-01-01

    CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS)–poly(styrene) (PS) and chitosan (CS)–poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2) = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C. PMID:27294964

  13. Effect of internal pressure and gas/liquid interface area on the CO mass transfer coefficient using hollow fibre membranes as a high mass transfer gas diffusing system for microbial syngas fermentation.

    PubMed

    Yasin, Muhammad; Park, Shinyoung; Jeong, Yeseul; Lee, Eun Yeol; Lee, Jinwon; Chang, In Seop

    2014-10-01

    This study proposed a submerged hollow fibre membrane bioreactor (HFMBR) system capable of achieving high carbon monoxide (CO) mass transfer for applications in microbial synthesis gas conversion systems. Hydrophobic polyvinylidene fluoride (PVDF) membrane fibres were used to fabricate a membrane module, which was used for pressurising CO in water phase. Pressure through the hollow fibre lumen (P) and membrane surface area per unit working volume of the liquid (A(S)/V(L)) were used as controllable parameters to determine gas-liquid volumetric mass transfer coefficient (k(L)a) values. We found a k(L)a of 135.72 h(-1) when P was 93.76 kPa and AS/VL was fixed at 27.5m(-1). A higher k(L)a of 155.16 h(-1) was achieved by increasing AS/VL to 62.5m(-1) at a lower P of 37.23 kPa. Practicality of HFMBR to support microbial growth and organic product formation was assessed by CO/CO2 fermentation using Eubacterium limosum KIST612.

  14. Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO₂ Separation from CH₄ and N₂.

    PubMed

    Otvagina, Ksenia V; Mochalova, Alla E; Sazanova, Tatyana S; Petukhov, Anton N; Moskvichev, Alexandr A; Vorotyntsev, Andrey V; Afonso, Carlos A M; Vorotyntsev, Ilya V

    2016-06-09

    CO₂ separation was found to be facilitated by transport membranes based on novel chitosan (CS)-poly(styrene) (PS) and chitosan (CS)-poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF₄], [bmim][PF₆], and [bmim][Tf₂N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75-104 MPa for CS-PAN and 69-75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO₂ permeability 400 Barrers belongs to CS-b-PS/[bmim][BF₄]. The highest selectivity α (CO₂/N₂) = 15.5 was achieved for CS-b-PAN/[bmim][BF₄]. The operational temperature of the membranes is under 220 °C.

  15. Functional membranes. Present and future

    NASA Technical Reports Server (NTRS)

    Kunitake, T.

    1982-01-01

    The present situation and the future development of the functional membrane are discussed. It is expected that functional membranes will play increasingly greater roles in the chemical industry of the coming decade. These membranes are formed from polymer films, liquid membranes or bilayer membranes. The two most important technologies based on the polymeric membrane are reverse osmosis and ion exchange. The liquid membrane is used for separation of ionic species; an extension of the solvent extraction process. By using appropriate ligands and ionophores, highly selective separations are realized. The active transport is made possible if the physical and chemical potentials are applied to the transport process. More advanced functional membranes may be designed on the basis of the synthetic bilayer membrane.

  16. Nickel (II) Preconcentration and Speciation Analysis During Transport from Aqueous Solutions Using a Hollow-fiber Permeation Liquid Membrane (HFPLM) Device

    PubMed Central

    Bautista-Flores, Ana Nelly; de San Miguel, Eduardo Rodríguez; de Gyves, Josefina; Jönsson, Jan Åke

    2011-01-01

    Nickel (II) preconcentration and speciation analysis using a hollow fiber supported liquid membrane (HFSLM) device was studied. A counterflow of protons coupled to complexation with formate provided the driving force of the process, while Kelex 100 was employed as carrier. The influence of variables related to module configuration (acceptor pH and carrier concentration) and to the sample properties (donor pH) on the preconcentration factor, E, was simultaneously studied and optimized using a 3 factor Doehlert matrix response surface methodology. The effect of metal concentration was studied as well. Preconcentration factors as high as 4240 were observed depending on the values of the different variables. The effects of the presence of inorganic anions (NO2−, SO42−, Cl−, NO3−, CO32−, CN−) and dissolved organic matter (DOM) in the form of humic acids were additionally considered in order to carry out a speciation analysis study. Nickel preconcentration was observed to be independent of both effects, except when cyanide was present in the donor phase. A characterization of the transport regime was performed through the analysis of the dependence of E on the temperature. E increases with the increase in temperature according to the equation E(K) = −8617.3 + 30.5T with an activation energy of 56.7 kJ mol−1 suggesting a kinetic-controlled regime. Sample depletion ranged from 12 to 1.2% depending on the volume of the donor phase (100 to 1000 mL, respectively). PMID:24957733

  17. Electronic simulation of the supported liquid membrane in electromembrane extraction systems: Improvement of the extraction by precise periodical reversing of the field polarity.

    PubMed

    Moazami, Hamid Reza; Nojavan, Saeed; Zahedi, Pegah; Davarani, Saied Saeed Hosseiny

    2014-09-02

    In order to understand the limitations of electromebrane extraction procedure better, a simple equivalent circuit has been proposed for a supported liquid membrane consisting of a resistor and a low leakage capacitor in series. To verify the equivalent circuit, it was subjected to a simulated periodical polarity changing potential and the resulting time variation of the current was compared with that of a real electromembrane extraction system. The results showed a good agreement between the simulated current patterns and those of the real ones. In order to investigate the impact of various limiting factors, the corresponding values of the equivalent circuit were estimated for a real electromembrane extraction system and were attributed to the physical parameters of the extraction system. A dual charge transfer mechanism was proposed for electromembrane extraction by combining general migration equation and fundamental aspects derived from the simulation. Dual mechanism comprises a current dependent contribution of analyte in total current and could support the possibility of an improvement in performance of an electromembrane extraction by application of an asymmetric polarity changing potential. The optimization of frequency and duty cycle of the asymmetric polarity exchanging potential resulted in a higher recovery (2.17 times greater) in comparison with the conventional electromebrane extraction. The simulation also provided more quantitative approaches toward the investigation of the mechanism of extraction and contribution of different limiting factors in electromembrane extraction. Results showed that the buildup of the double layer is the main limiting factor and the Joule heating has lesser impact on the performance of an electromebrane extraction system.

  18. Determination of cocaine and its metabolites in plasma by porous membrane-protected molecularly imprinted polymer micro-solid-phase extraction and liquid chromatography-tandem mass spectrometry.

    PubMed

    Sánchez-González, Juan; García-Carballal, Sara; Cabarcos, Pamela; Tabernero, María Jesús; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2016-06-17

    A selective molecularly imprinted polymer synthesized for the selective retention of cocaine (COC) and its metabolites [benzoylecgonine (BZE), ecgonine methyl ester (EME), and cocaethylene (CE)] was used as a solid adsorbent for assessing cocaine abuse by plasma analysis. The MIP beads (50mg) were loaded inside a cone shaped device made of a polypropylene (PP) membrane for micro-solid-phase extraction (μ-SPE). High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used for quantifying the analytes after MIP-μ-SPE. The best retention capabilities were reached when loading plasma samples (within the 0.1-5.0mL range), previously adjusted to pH 5.5 by orbital-horizontal shaking (150rpm, 50°C) for 10min. Analyte elution was achieved by subjecting the MIP-μ-SPE device to ultrasound (37kHz, 325W) with 10mL of dichloromethane/2-propanol/ammonium hydroxide (76:20:4) for 8min. After eluate evaporation to dryness and re-dissolution in 100μL of mobile phase, the MIP-μ-SPE method yielded a pre-concentration factor of 50. Precision was assessed by intra-day and inter-day assays, and accuracy (intraday and inter-day analytical recovery, as well as the analysis of a BTMF 1/11-B control serum sample) show that the developed method is highly precise and accurate. In addition, the limits of detection, ranging from 0.061ngmL(-1) for COC to 0.87ngmL(-1) for BZE, were low enough for confirmative conclusions regarding cocaine abuse. The method was used for screening/quantifying cocaine and metabolites in plasma samples from poly-drug abusers.

  19. Optimised extraction of heterocyclic aromatic amines from blood using hollow fibre membrane liquid-phase microextraction and triple quadrupole mass spectrometry.

    PubMed

    Cooper, Kevin M; Jankhaikhot, Natcha; Cuskelly, Geraldine

    2014-09-05

    Heterocyclic aromatic amines (HCA) are carcinogenic mutagens formed during cooking of proteinaceous foods, particularly meat. To assist in the ongoing search for biomarkers of HCA exposure in blood, a method is described for the extraction from human plasma of the most abundant HCAs: 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (and its isomer 7,8-DiMeIQx), using hollow fibre membrane liquid-phase microextraction. This technique employs 2.5cm lengths of porous polypropylene fibres impregnated with organic solvent to facilitate simultaneous extraction from an alkaline aqueous sample into a low volume acidic acceptor phase. This low cost protocol is extensively optimised for fibre length, extraction time, sample pH and volume. Detection is by UPLC-MS/MS using positive mode electrospray ionisation with a 3.4min runtime, with optimum peak shape, sensitivity and baseline separation being achieved at pH 9.5. To our knowledge this is the first description of HCA chromatography under alkaline conditions. Application of fixed ion ratio tolerances for confirmation of analyte identity is discussed. Assay precision is between 4.5 and 8.8% while lower limits of detection between 2 and 5pg/mL are below the concentrations postulated for acid-labile HCA-protein adducts in blood.

  20. Novel ceramic-polymer composite membranes for the separation of liquid waste. Annual progress report, September 15, 1996--September 14, 1997

    SciTech Connect

    Cohen, Y.

    1997-01-01

    'The project on ceramic-supported polymer membranes focuses on the development of a novel class of membranes for the separation of organics from both organic-aqueous and organic-organic mixtures, Theses membranes are fabricated by a graft polymerization process where polymer chains are grown onto the surface of a ceramic support membrane. The surface graft polymerization process, developed at UCLA, results in the formation of a thin polymer layer covalently bonded to the membrane pore surface as a layer of terminally anchored polymeric chains. Through the selection of the polymer most appropriate for the desired separation task, the graft polymerized surface layer can be synthesized to impart specific separation properties to the membrane. It is expected that this project will lead to the demonstration of a new technology for the tailor design of a new class of selective and robust ceramic-supported polymer membranes. This new approach will allow the rapid deployment of task-specific membranes for the separation of waste constituents for subsequent recovery, treatment or disposal. Progress to date includes the preparation of successful silica-polyvinylpyrrolidone (PVP) membrane for the treatment of oil-in-water emulsions and a silica-polyvinylacetate (PVAc) pervaporation membrane for the separation of organics from water. Current work is ongoing to study the performance of the pervaporation membrane for the removal of chlorinated organics from water and to develop a pervaporation membrane for organic-organic separation. In another aspect of the study, the authors are studying the hydrophilic PVP CSP membrane for oil-in-water emulsion treatment with the goal of determining the optimal membrane polymer surface structure as a function of various operating conditions (e.g., tube-side Reynolds number and transmembrane pressure), Work is also in progress to characterize the polymer layer by AFM and internal reflection FTIR, and to model the conformation of the polymer

  1. Macromolecular liquids

    SciTech Connect

    Safinya, C.R.; Safran, S.A. ); Pincus, P.A. )

    1990-01-01

    Liquids include a broad range of material systems which are of high scientific and technological interest. Generally speaking, these are partially ordered or disordered phases where the individual molecular species have organized themselves on length scales which are larger than simple fluids, typically between 10 Angstroms and several microns. The specific systems reported on in this book include membranes, microemulsions, micelles, liquid crystals, colloidal suspensions, and polymers. They have a major impact on a broad spectrum of technological industries such as displays, plastics, soap and detergents, chemicals and petroleum, and pharmaceuticals.

  2. Organic fluid permeation through fluoropolymer membranes

    DOEpatents

    Nemser, Stuart M.; Kosaraju, Praveen; Bowser, John

    2015-07-14

    Separation of the components of liquid mixtures is achieved by contacting a liquid mixture with a nonporous membrane having a fluoropolymer selectively permeable layer and imposing a pressure gradient across the membrane from feed side to permeate side. Unusually high transmembrane flux is obtained when the membrane is subjected to one or more process conditions prior to separation. These include (a) leaving some residual amount of membrane casting solvent in the membrane, and (b) contacting the membrane with a component of the mixture to be separated for a duration effective to saturate the membrane with the component.

  3. The Molecules of the Cell Membrane.

    ERIC Educational Resources Information Center

    Bretscher, Mark S.

    1985-01-01

    Cell membrane molecules form a simple, two-dimensional liquid controlling what enters and leaves the cell. Discusses cell membrane molecular architecture, plasma membranes, epithelial cells, cycles of endocytosis and exocytosis, and other topics. Indicates that some cells internalize, then recycle, membrane area equivalent to their entire surface…

  4. An online coupled peritoneal macrophage/cell membrane chromatography and high-performance liquid chromatography/mass spectrometry method to screen for anti-inflammatory components from the Chinese traditional medicine Chloranthus multistachys Pei.

    PubMed

    Li, Weifeng; Xing, Wei; Wang, Sicen; Fan, Ting; Huang, Huimin; Niu, Xiaofeng; He, Langchong

    2013-11-01

    Cell membrane chromatography (CMC) is a chromatographic biological affinity method that uses specific cell membranes as the stationary phase. In this study, a novel peritoneal macrophage/cell membrane chromatography (PM/CMC)-online-high performance liquid chromatography/mass spectrometry (HPLC/MS) method was established to screen for the anti-inflammatory components from traditional Chinese medicines using hydrocortisone and dexamethasone as standards. The stationary phase of the CMC employed mouse peritoneal macrophage cell membranes. This method was applied to the purification and identification of components in extracts of Chloranthus multistachys Pei. The major component retained by CMC was identified as isofraxidin by HPLC/MS. In vitro experiments revealed that IF was able to inhibit the production of nitric oxide and tumor necrosis factor-α in lipopolysaccharide-stimulated mice and peritoneal macrophages in a dose-dependent manner. The results demonstrated that the PM/CMC-online-HPLC/MS is an effective screening system for the rapid detection, enrichment, and identification of target components from complex samples.

  5. Consider nanofiltration for membrane separations

    SciTech Connect

    Raman, L.P. ); Cheryna, M.; Rajagopalan, N. )

    1994-03-01

    The best known liquid-phase membrane processes are reverse osmosis (RO), ultrafiltration (UF), microfiltration (MF), dialysis, and electrodialysis (ED). However, over the past few years, a new membrane process called nanofiltration (NF) has emerged that promises to significantly widen the application of membranes in liquid-phase separations. This paper discusses the following: NF operating range, membrane properties, and the following applications: demineralizing water, cleaning up contaminated groundwater, ultrapure water, effluents containing heavy metals, offshore oil platforms, yeast production, pulp and paper mills, textile production, electroless copper plating, and cheese whey production.

  6. Fuel cell membrane humidification

    DOEpatents

    Wilson, Mahlon S.

    1999-01-01

    A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

  7. Permeable membrane experiment

    NASA Technical Reports Server (NTRS)

    Slavin, Thomas J.; Cao, Tuan Q.; Kliss, Mark H.

    1993-01-01

    The purpose of the Permeable Membrane Experiment is to gather flight data on three areas of membrane performance that are influenced by the presence of gravity. These areas are: (1) Liquid/gas phase separation, (2) gas bubble interference with diffusion through porous membranes and (3) wetting characteristics of hydrophilic membrane surfaces. These data are important in understaning the behavior of membrane/liquid/gas interfaces where surface tension forces predominate. The data will be compared with 1-g data already obtained and with predicted micrograviity behavior. The data will be used to develop designs for phase separation and plant nutrient delivery systems and will be available to the life support community for use in developing technologies which employ membranes. A conceptual design has been developed to conduct three membrane experiments, in sequence, aboard a single Complex Autonomous Payload (CAP) carrier to be carried in the Shuttle Orbiter payload bay. One experiment is conducted for each of the three membrane performance areas under study. These experiments are discussed in this paper.

  8. From channel-forming ionic liquid crystals exhibiting humidity-induced phase transitions to nanostructured ion-conducting polymer membranes (adv. Mater. 26/2013).

    PubMed

    Zhang, Heng; Li, Lei; Möller, Martin; Zhu, Xiaomin; Rueda, Jaime J Hernandez; Rosenthal, Martin; Ivanov, Dimitri A

    2013-07-12

    A novel wedge-shaped amphiphilic molecule bearing a sulfonate group at the tip displays humidity-induced phase transitions from a hexagonal columnar structure to a bicontinuous cubic phase. The mesophases can be frozen by photopolymerization of acrylic end-groups resulting in free-standing membranes with different topology of ionic nanochannels. The obtained membranes with a well-ordered ionic channel structure hold promise for applications in separation and catalysis.

  9. Evaluation of a hollow fiber supported liquid membrane device as a chemical surrogate for the measurements of zinc (II) bioavailability using two microalgae strains as biological references.

    PubMed

    Rodríguez-Morales, Erik A; Rodríguez de San Miguel, Eduardo; de Gyves, Josefina

    2017-03-01

    The environmental bioavailability of zinc (II), i.e., the uptake of the element by an organism, was determined using two microalgae species, Scenedesmus acutus and Pseudokirchneriella subcapitata, and estimated using hollow fiber supported liquid membrane (HF-SLM) device as the chemical surrogate. Several experimental conditions were studied including the presence of organic matter, inorganic anions and concomitant cations and pH. The results show strong positive correlation coefficients between the responses given by the HF-SLM and the microalgae species (r = 0.900 for S. acutus and r = 0.876 for P. subcapitata) in multivariate environments (changes in pH, calcium, humic and citrate concentrations). The maximum amount of zinc (II) retained by the HF-SLM (4.7 × 10(-8) mol/cm(2)) was higher than those for P. subcapitata and S. acutus (9.4 × 10(-11) mol/cm(2) and 6.2 × 10(-11) mol/cm(2), respectively). The variation in pH (pH 5.5-9) was the variable with the greatest effect on zinc internalization in all systems, increasing approximately 2.5 times for P. subcapitata and 5.5 times for S. acutus respect to pH = 5.5, while the presence of humic acids did not affect the response. The species' concentration analysis of the experimental design at pH = 5.5 indicated that the amount of internalized zinc (II) by the HF-SLM and both microalgae species is strongly dependent on the free zinc concentration (r = 0.910 for the HF-SLM, r = 0.922 for S. acutus and r = 0.954 for P. subcapitata); however, at pH = 9.0, the amount of internalized zinc (II) is strongly dependent on the sum of free zinc and labile species (r = 0.912 for the HF-SLM, r = 0.947 for S. acutus and r = 0.900 for P. subcapitata). The presence of inorganic ligands (chloride, sulfate, phosphate, carbonate, and nitrate) and metal ions (cobalt (II), copper (II), nickel (II), chromium (VI), lead (II) and cadmium (II)) produced different behaviors both in the chemical surrogate and the

  10. Cyclic membrane separation process

    DOEpatents

    Bowser, John

    2004-04-13

    A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In one of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the other part, the membrane is inoperative while gas pressure rises in the ullage. Ambient air is charged to the membrane separation unit during the latter part of the cycle.

  11. Cyclic membrane separation process

    DOEpatents

    Nemser, Stuart M.

    2005-05-03

    A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In the first part of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the second part, the membrane is inoperative while gas pressure rises in the ullage. In one aspect of this invention, a vacuum is drawn in the membrane separation unit thus reducing overall VOC emissions.

  12. Ceramic membrane development in NGK

    NASA Astrophysics Data System (ADS)

    Araki, Kiyoshi; Sakai, Hitoshi

    2011-05-01

    NGK Insulators, Ltd. was established in 1919 to manufacture the electric porcelain insulators for power transmission lines. Since then, our business has grown as one of the world-leading ceramics manufacturing companies and currently supply with the various environmentally-benign ceramic products to worldwide. In this paper, ceramic membrane development in NGK is described in detail. We have been selling ceramic microfiltration (MF) membranes and ultra-filtration (UF) membranes for many years to be used for solid/liquid separation in various fields such as pharmaceutical, chemical, food and semiconductor industries. In Corporate R&D, new ceramic membranes with sub-nanometer sized pores, which are fabricated on top of the membrane filters as support, are under development for gas and liquid/liquid separation processes.

  13. Membrane-Mediated Interactions Measured Using Membrane Domains

    PubMed Central

    Semrau, Stefan; Idema, Timon; Schmidt, Thomas; Storm, Cornelis

    2009-01-01

    Abstract Cell membrane organization is the result of the collective effect of many driving forces. Several of these, such as electrostatic and van der Waals forces, have been identified and studied in detail. In this article, we investigate and quantify another force, the interaction between inclusions via deformations of the membrane shape. For electrically neutral systems, this interaction is the dominant organizing force. As a model system to study membrane-mediated interactions, we use phase-separated biomimetic vesicles that exhibit coexistence of liquid-ordered and liquid-disordered lipid domains. The membrane-mediated interactions between these domains lead to a rich variety of effects, including the creation of long-range order and the setting of a preferred domain size. Our findings also apply to the interaction of membrane protein patches, which induce similar membrane shape deformations and hence experience similar interactions. PMID:19527649

  14. Profile structures of the voltage-sensor domain and the voltage-gated K+-channel vectorially oriented in a single phospholipid bilayer membrane at the solid-vapor and solid-liquid interfaces determined by x-ray interferometry

    NASA Astrophysics Data System (ADS)

    Gupta, S.; Liu, J.; Strzalka, J.; Blasie, J. K.

    2011-09-01

    One subunit of the prokaryotic voltage-gated potassium ion channel from Aeropyrum pernix (KvAP) is comprised of six transmembrane α helices, of which S1-S4 form the voltage-sensor domain (VSD) and S5 and S6 contribute to the pore domain (PD) of the functional homotetramer. However, the mechanism of electromechanical coupling interconverting the closed-to-open (i.e., nonconducting-to-K+-conducting) states remains undetermined. Here, we have vectorially oriented the detergent (OG)-solubilized VSD in single monolayers by two independent approaches, namely “directed-assembly” and “self-assembly,” to achieve a high in-plane density. Both utilize Ni coordination chemistry to tether the protein to an alkylated inorganic surface via its C-terminal His6 tag. Subsequently, the detergent is replaced by phospholipid (POPC) via exchange, intended to reconstitute a phospholipid bilayer environment for the protein. X-ray interferometry, in which interference with a multilayer reference structure is used to both enhance and phase the specular x-ray reflectivity from the tethered single membrane, was used to determine directly the electron density profile structures of the VSD protein solvated by detergent versus phospholipid, and with either a moist He (moderate hydration) or bulk aqueous buffer (high hydration) environment to preserve a native structure conformation. Difference electron density profiles, with respect to the multilayer substrate itself, for the VSD-OG monolayer and VSD-POPC membranes at both the solid-vapor and solid-liquid interfaces, reveal the profile structures of the VSD protein dominating these profiles and further indicate a successful reconstitution of a lipid bilayer environment. The self-assembly approach was similarly extended to the intact full-length KvAP channel for comparison. The spatial extent and asymmetry in the profile structures of both proteins confirm their unidirectional vectorial orientation within the reconstituted membrane and

  15. Extraction and preconcentration of tylosin from milk samples through functionalized TiO₂ nanoparticles reinforced with a hollow fiber membrane as a novel solid/liquid-phase microextraction technique.

    PubMed

    Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Dorraji, Mir Saeed Seyed

    2014-08-01

    The aim of this study was to introduce a novel, simple, and highly sensitive preparation method for determination of tylosin in different milk samples. In the so-called functionalized TiO2 hollow fiber solid/liquid-phase microextraction method, the acceptor phase is functionalized TiO2 nanoparticles that are dispersed in the organic solvent and held in the pores and lumen of a porous polypropylene hollow fiber membrane. An effective functionalization of TiO2 nanoparticles has been done in the presence of aqueous H2 O2 and a mild acidic ambient under UV irradiation. This novel extraction method showed excellent extraction efficiency and a high enrichment factor (540.2) in comparison with conventional hollow fiber liquid-phase microextraction. All the experiments were monitored at λmax = 284 nm using a simple double beam UV-visible spectrophotometer. A Taguchi orthogonal array experimental design with an OA16 (4(5) ) matrix was employed to optimize the factors affecting the efficiency of hollow fiber solid/liquid-phase microextraction such as pH, stirring rate, salt addition, extraction time, and the volume of donor phase. This developed method was successfully applied for the separation and determination of tylosin in milk samples with a linear concentration range of 0.51-7000 μg/L (r(2) = 0.991) and 0.21 μg/L as the limit of detection.

  16. Membrane stabilizer

    DOEpatents

    Mingenbach, William A.

    1988-01-01

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material.

  17. Acidic Ionic Liquids.

    PubMed

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  18. Pervaporation separation of binary organic-aqueous liquid mixtures using crosslinked PVA membranes. I. Characterization of the reaction between PVA and PAA

    SciTech Connect

    Jiwon Rhim; Kewho Lee . Membranes and Separation Lab.); Minyoung Sohn; Hyeokjong Joo . Dept. of Polymer Science and Engineering)

    1993-10-20

    For the purpose of the water-selective membrane material development for pervaporation separation, poly(vinyl alcohol) (PVA) was crosslinked with a low molecular weight of poly(acrylic acid) (PAA). The crosslinking reactions between PVA and PAA were characterized through IR spectroscopy, differential scanning calorimetry (DSC), and tensile tests when varying the reaction conditions, that is, time, temperature, amounts of cross-linking agents, PAA. It was found that the crosslinking reaction was fast: in other words, that the reaction mainly occurred at the initial step of each reaction condition. The best reaction conditions for preparing the crosslinked PVA membranes were found to be: reaction time not over 1 h, reaction temperature in the range of 150-180 C. PAA contents of 15-20 wt% were found satisfactory with respect to the application areas.

  19. Continuous treatment of the organic fraction of municipal solid waste in an anaerobic two-stage membrane process with liquid recycle.

    PubMed

    Trzcinski, A P; Stuckey, D C

    2009-05-01

    The stability and performance of a two-stage anaerobic membrane process was investigated at different organic loading rates (OLRs) and Hydraulic Retention Times (HRTs) over 200 days. The Hydrolytic Reactor (HR) was fed with the Organic Fraction of Municipal Solid Waste (OFMSW), while the leachate from the HR was fed continuously to two Submerged Anaerobic Membrane Bioreactors (SAMBR1 and 2). The Total COD (TCOD) of the leachate varied over a wide range, typically between 4000 and 26,000 mg/L while the Soluble COD (SCOD) in the permeate was in the range 400-600 mg/L, achieving a COD removal greater than 90% at a HRT of 1.6-2.3 days in SAMBR1. The operation was not sustainable below this HRT due to a membrane flux limitation at 0.5-0.8L/m(2) h (LMH), which was linked to the increasing MLTSS. SCOD in the recycled permeate did not build up indicating a slow degradation of recalcitrants over time. SAMBR2 was run in parallel with SAMBR1 but its permeate was treated aerobically in an Aerobic Membrane Bioreactor (AMBR). The AMBR acted as a COD-polishing and ammonia removal step. About 26% of the recalcitrant SCOD from SAMBR2 could be aerobically degraded in the AMBR. In addition, 97.7 % of the ammonia-nitrogen was converted to nitrate in the AMBR at a maximum nitrogen-loading rate of 0.18 kg NH(4)(+)-N/m(3) day. GC-MS analysis was performed on the reactor effluents to determine their composition and what compounds were recalcitrant.

  20. Ion and Bio-Selective Membrane Electrodes.

    ERIC Educational Resources Information Center

    Rechnitz, Garry A.

    1983-01-01

    Discusses topics on membrane electrodes corresponding to approximately six hours of lecture time. These include glass, liquid, crystal, gas-sensing membrane electrodes as well as enzyme and other bioselective membrane electrodes. Instructional strategies and other topics which might be discussed are provided. (JN)

  1. Evaluation of the measurement of Cu(II) bioavailability in complex aqueous media using a hollow-fiber supported liquid membrane device (HFSLM) and two microalgae species (Pseudokirchneriella subcapitata and Scenedesmus acutus).

    PubMed

    Rodríguez-Morales, Erik A; Rodríguez de San Miguel, Eduardo; de Gyves, Josefina

    2015-11-01

    The environmental bioavailability of copper was determined using a hollow-fiber supported liquid membrane (HFSLM) device as a chemical surrogate and two microalgae species (Scenedesmus acutus and Pseudokirchneriella subcapitata). Several experimental conditions were studied: pH, the presence of organic matter, inorganic anions, and concomitant cations. The results indicated a strong relationship between the response given by the HFSLM and the microalgae species with free copper concentrations measured by an ion selective electrode (ISE), in accordance with the free-ion activity model (FIAM). A significant positive correlation was evident when comparing the bioavailability results measured by the HFSLM and the S. acutus microalga species, showing that the synthetic device may emulate biological uptake and, consequently, be used as a chemical test for bioavailability measurements using this alga as a biological reference.

  2. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  3. Ultrathin-skinned asymmetric membranes by immiscible solvents treatment

    DOEpatents

    Friesen, D.T.; Babcock, W.C.

    1989-11-28

    Improved semipermeable asymmetric fluid separation membranes useful in gas, vapor and liquid separations are disclosed. The membranes are prepared by substantially filling the pores of asymmetric cellulosic semipermeable membranes having a finely porous layer on one side thereof with a water immiscible organic liquid, followed by contacting the finely porous layer with water.

  4. Impact of liquid water on oxygen reaction in cathode catalyst layer of proton exchange membrane fuel cell: A simple and physically sound model

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoxian; Gao, Yuan

    2016-06-01

    When cells work at high current density, liquid water accumulates in their catalyst layer (CL) and the gaseous oxygen could dissolve into the water and the ionomer film simultaneously; their associated dissolved concentrations in equilibrium with the gaseous oxygen are also different. Based on a CL acquired using tomography, we present new methods in this paper to derive agglomerate models for partly saturated CL by viewing the movement and reaction of the dissolved oxygen in the two liquids (water and ionomer) and the agglomerate as two independent random processes. Oxygen dissolved in the water moves differently from oxygen dissolved in the ionomer, and to make the analysis tractable, we use an average distribution function to describe the average movement of all dissolved oxygen. A formula is proposed to describe this average distribution function, which, in combination with the exponential distribution assumed in the literature for oxygen reaction, leads to a simple yet physically sound agglomerate model. The model has three parameters which can be directly calculated from CL structure rather than by calibration. We explain how to calculate these parameters under different water contents for a given CL structure, and analyse the impact of liquid water on cell performance.

  5. Membrane stabilizer

    DOEpatents

    Mingenbach, W.A.

    1988-02-09

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

  6. CO2/light gas separation performance of cross-linked poly(vinylimidazolium) gel membranes as a function of ionic liquid loading and cross-linker content

    SciTech Connect

    Carlisle, TK; Nicodemus, GD; Gin, DL; Noble, RD

    2012-04-15

    A series of cross-linked poly(vinylimidazolium)-RTIL gel membranes was synthesized and evaluated for room-temperature, ideal CO2/N-2, CO2/CH4, and CO2/H-2 separation performance. The membranes were formed by photo-polymerization of oligo(ethylene glycol)-functionalized cross-linking (i.e., di-functional) and non-cross-linking (i.e., mono-functional) vinylimidazolium RTIL monomers with nonpolymerizable, "free RTIL." The effect of free RTIL ([emim][Tf2N]) loading on CO2 separation performance was evaluated by varying RTIL loading at three levels (45, 65, and 75 wt.%). The effect of cross-linker content on CO2 separation performance was also evaluated by varying the copolymer composition of cross-linked membranes from 5 to 100 mol% di-functional monomer. The substituent on the monofunctional RTIL monomer was also varied to investigate the effect of substituent structure and chemistry on CO2 separation performance. CO2 permeability was dramatically increased with higher loading of free RTIL. Increased RTIL loading had no effect on CO2/N-2 or CO2/CH4 permeability selectivity, but significantly improved CO2/H-2 permeability selectivity. Reducing the cross-linking monomer concentration generally improved CO2 permeability. However, anomalous permeability and selectivity behavior was observed below critical concentrations of cross-linker. The effect of the substituent on the monofunctional monomer on CO2 separation performance was minimal compared to the effects of RTIL loading and copolymer composition. (C) 2012 Elsevier B.V. All rights reserved.

  7. Detection of Prostate Specific Membrane Antigen at Picomolar Levels Using Biocatalysis Coupled to Assisted Ion Transfer Voltammetry at a Liquid-Organogel Microinterface Array.

    PubMed

    Akter, Rashida; Arrigan, Damien W M

    2016-12-06

    A label-free electrochemical strategy for the detection of a cancer biomarker, prostate specific membrane antigen (PSMA), at picomolar concentrations without the use of antibodies, was investigated. The approach is based on the assisted ion transfer of protons, generated by a series of enzymatic reactions, at an array of microinterfaces between two immiscible electrolyte solutions (μ-ITIES). This nonredox electrochemical approach based on biocatalysis-coupled proton transfer at the μ-ITIES array opens a new way to detect the prostate cancer biomarker, with detection capability achieved at concentrations below those indicative of disease presence. The strategy is expected to contribute to cancer diagnostics, recurrence monitoring, and therapeutic treatment efficacy.

  8. Entropic Tension in Crowded Membranes

    PubMed Central

    Lindén, Martin; Sens, Pierre; Phillips, Rob

    2012-01-01

    Unlike their model membrane counterparts, biological membranes are richly decorated with a heterogeneous assembly of membrane proteins. These proteins are so tightly packed that their excluded area interactions can alter the free energy landscape controlling the conformational transitions suffered by such proteins. For membrane channels, this effect can alter the critical membrane tension at which they undergo a transition from a closed to an open state, and therefore influence protein function in vivo. Despite their obvious importance, crowding phenomena in membranes are much less well studied than in the cytoplasm. Using statistical mechanics results for hard disk liquids, we show that crowding induces an entropic tension in the membrane, which influences transitions that alter the projected area and circumference of a membrane protein. As a specific case study in this effect, we consider the impact of crowding on the gating properties of bacterial mechanosensitive membrane channels, which are thought to confer osmoprotection when these cells are subjected to osmotic shock. We find that crowding can alter the gating energies by more than in physiological conditions, a substantial fraction of the total gating energies in some cases. Given the ubiquity of membrane crowding, the nonspecific nature of excluded volume interactions, and the fact that the function of many membrane proteins involve significant conformational changes, this specific case study highlights a general aspect in the function of membrane proteins. PMID:22438801

  9. Catalytic nanoporous membranes

    DOEpatents

    Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

    2013-08-27

    A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

  10. Development of an in vitro liquid chromatography-mass spectrometry method to evaluate stereo and chemical stability of new drug candidates employing immobilized artificial membrane column.

    PubMed

    Cannazza, Giuseppe; Battisti, Umberto M; Carrozzo, Marina M; Cazzato, Addolorata S; Braghiroli, Daniela; Parenti, Carlo; Troisi, Luigino

    2014-10-10

    A stopped-flow HPLC method was developed to evaluate configurational and chemical stability of pharmaceutical compounds employing immobilized artificial membranes (IAM) column to simulate conditions that pharmaceutical compounds will meet in vivo. The method was applied to recent developed chiral 5-arylbenzothiadiazine derivatives possessing high positive allosteric modulatory (PAM) activity on AMPA receptor. In particular the stopped-flow HPLC method developed used a chiral column to separate single enantiomer of the compounds that are forced into an IAM column where configurational and chemical stability was evaluated in simulated gastrointestinal fluids (pH 1.2 and 6.8 at 37.5 °C) to simulate in vivo conditions. The results were compared to those obtained by dynamic and off-column methods to evaluate the effects of stationary phases on kinetic constant of enantiomerization and hydrolysis. The results suggested that the phospholipids environment of IAM stationary phases, which mimes biological membrane, greatly influence the hydrolysis process increasing the chemical stability of tested compounds while no influence on enantiomerization kinetic was observed. Therefore it is possible to suppose that 5-arylbenzothiadiazine derivatives should not hydrolysed in vivo while they should rapidly racemized in aqueous solvents. The method could represents a rapid and value tool to predict chemical and configurational stability of new chemical entities to decrease the number of animal studies.

  11. Separation of gas from solvent by membrane technology

    SciTech Connect

    Beaupre, R.F.; Jung, D.Y.

    1991-02-26

    This patent describes the method of separating a charge rich liquid containing gas dissolved in solvent. It comprises: maintaining the charge rich liquid containing gas dissolved in solvent therefore in liquid phase in contact with a gas-permeable, essentially solvent impermeable membrane of pore size of less than about 1000 A and molecular weight cutoff of below about 1,000 selected from the group consisting of cellulose acetate membrane, hydrolyzed cellulose membrane, and polyethyleneimine membrane, and; maintaining a pressure drop across the gas-permeable essentially solvent-impermeable membrane; passing the gas from the charge rich liquid containing gas dissolved in solvent therefore at the higher pressure side of the membrane through the membrane thereby forming lean liquid containing decreased quantities of gas dissolved in solvent on the higher pressure side of the membrane and, on the lower pressure side of the membrane, gas containing decreased quantities of liquid; recovering lean liquid containing decreased quantities of gas dissolved in solvent from the high pressure side of the membrane; and recovering gas containing decreased quantities of liquid from the lower pressure side of the membrane.

  12. CENTRIFUGAL MEMBRANE FILTRATION

    SciTech Connect

    Daniel J. Stepan; Bradley G. Stevens; Melanie D. Hetland

    1999-10-01

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc).

  13. Production of permeable cellulose triacetate membranes

    DOEpatents

    Johnson, Bruce M.

    1986-01-01

    A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

  14. Production of permeable cellulose triacetate membranes

    DOEpatents

    Johnson, B.M.

    1986-12-23

    A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

  15. Use of inhibitory solvents in multi-membrane bioreactor

    NASA Technical Reports Server (NTRS)

    Cho, Toohyon (Inventor); Shuler, Michael L. (Inventor)

    1990-01-01

    An immobilized liquid membrane is employed to allow use of a product-extracting solvent which is normally toxic toward a cell layer which produces the product in a membrane-moderated biological reaction.

  16. Variable-focus cylindrical liquid lens array

    NASA Astrophysics Data System (ADS)

    Zhao, Wu-xiang; Liang, Dong; Zhang, Jie; Liu, Chao; Zang, Shang-fei; Wang, Qiong-hua

    2013-06-01

    A variable-focus cylindrical liquid lens array based on two transparent liquids of different refractive index is demonstrated. An elastic membrane divides a transparent reservoir into two chambers. The two chambers are filled with liquid 1 and liquid 2, respectively, which are of different refractive index. The micro-clapboards help liquid 1, liquid 2 and the elastic membrane form a cylindrical lens array. Driving these two liquids to flow can change the shape of the elastic membrane as well as the focal length. In this design, the gravity effect of liquid can be overcome. A demo lens array of positive optical power is developed and tested. Moreover, a potential application of the proposed lens array for autostereoscopic 3D displays is emphasized.

  17. Catalytic nanoporous membranes

    DOEpatents

    Pellin, Michael J.; Hryn, John N.; Elam, Jeffrey W.

    2009-12-01

    A nanoporous catalytic membrane which displays several unique features including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity.

  18. Membrane Stability Testing

    SciTech Connect

    Hobbs, D.T.

    1997-09-30

    The Electrosynthesis Co. Inc. (ESC) was contracted by the Westinghouse Savannah River Company to investigate the long term performance and durability of cell components (anode, membrane, cathode) in an electrochemical caustic recovery process using a simulated SRC liquid waste as anolyte solution. This report details the results of two long-term studies conducted using an ICI FM01 flow cell. This cell is designed and has previously been demonstrated to scale up directly into the commercial scale ICI FM21 cell.

  19. Artificial Red Cells with Polyhemoglobin Membranes.

    DTIC Science & Technology

    1981-09-01

    preparing emulsions and ejecting cells from the oil phase. IX. REFERENCES 1. Wallace, H. W., Asher, W. J., and Li, N. N. Liquid - liquid oxygenation: a...1S. KEY WORDS (Continue, an reverse side if naceoay mnd identify by block number) Artificial Blood, Hemoglobin, Polyhemoglobin, Biotonometry Liquid ...cell-size microdroplets containing 30% of hemoglobin were held in liquid membrane capsules and treated with glutaralddhyde that cross linked the

  20. Separation of Cu2+, Cd2+ and Cr3+ in a Mixture Solution Using a Novel Carrier Poly(Methyl Thiazoleethyl Eugenoxy Acetate) with BLM (Bulk Liquid Membrane)

    NASA Astrophysics Data System (ADS)

    Djunaidi, M. C.; Khabibi; Ulumudin, I.

    2017-02-01

    The separation process using a novel carrier polyeugenol has active groups N and S has been done with the technique BLM. Polyeugenol has groups active N and S was synthesized from eugenol which is then polymerized into polyeugenol. This polymeric compounds was then acidified become acidic poly (eugenoksi acetate). After the acid formed, then the synthesis was continued by add 4-methyl-5-tiazoleetanol to form esters poly (methyl thiazole eugenoxy ethyl acetate) (PMTEEA). The result of the synthesis was analyzed by FTIR and 1H NMR. This polyester product synthesis was applied as a carrier for separating metal ions Cu2+, Cd2+ and Cr3+ with variations in feed phase pH = 5 and pH = 7 in the membrane of chloroform using techniques BLM. Receiving phase after 24 hours was analyzed by AAS. In variations of feed pH = 5 ions was obtained 66.21% Cd2+, 28.83% Cu2+ and 10.92% of Cr3+, at pH = 7 was obtained 70.77% Cd2+, 30.14% Cu2+, and 3.72% of Cr3+.

  1. Different retention behavior of structurally diverse basic and neutral drugs in immobilized artificial membrane and reversed-phase high performance liquid chromatography: comparison with octanol-water partitioning.

    PubMed

    Vrakas, Demetris; Giaginis, Costas; Tsantili-Kakoulidou, Anna

    2006-05-26

    The retention behavior of 43 structurally diverse neutral and basic drugs in immobilized artificial membrane chromatography was investigated and compared to the reversed-phase retention and octanol-water partitioning. IAM chromatography was performed using morpholinepropanesulfonic acid (MOPS) or phosphate buffer saline (PBS) at pH 7.4 as the aqueous component of the mobile phase. The differences in the retention factors were attributed to increased electrostatic interactions in the MOPS environment, dependent on the fraction of charged species. Electrostatic interactions were found to play a key role in the relationships with reversed-phase retention factors determined under two different mobile phase conditions as well as in the relationships with lipophilicity data. IAM retention factors correlated better with octanol-water partition coefficients log P than with log D(7.4), as a result of the contribution of electrostatic forces in IAM retention. With log D(7.4) the relationships were improved when the fraction of charged species was taken into consideration. In any case the regression coefficient of log P or log D(7.4) was considerably lower than 1 reflecting the reduced hydrophobic environment of the IAM stationary phase. The different data sets were submitted to principal component analysis for further exploration of their similarities/dissimilarities.

  2. Hydrophobic Compounds Reshape Membrane Domains

    PubMed Central

    Barnoud, Jonathan; Rossi, Giulia; Marrink, Siewert J.; Monticelli, Luca

    2014-01-01

    Cell membranes have a complex lateral organization featuring domains with distinct composition, also known as rafts, which play an essential role in cellular processes such as signal transduction and protein trafficking. In vivo, perturbations of membrane domains (e.g., by drugs or lipophilic compounds) have major effects on the activity of raft-associated proteins and on signaling pathways, but they are difficult to characterize because of the small size of the domains, typically below optical resolution. Model membranes, instead, can show macroscopic phase separation between liquid-ordered and liquid-disordered domains, and they are often used to investigate the driving forces of membrane lateral organization. Studies in model membranes have shown that some lipophilic compounds perturb membrane domains, but it is not clear which chemical and physical properties determine domain perturbation. The mechanisms of domain stabilization and destabilization are also unknown. Here we describe the effect of six simple hydrophobic compounds on the lateral organization of phase-separated model membranes consisting of saturated and unsaturated phospholipids and cholesterol. Using molecular simulations, we identify two groups of molecules with distinct behavior: aliphatic compounds promote lipid mixing by distributing at the interface between liquid-ordered and liquid-disordered domains; aromatic compounds, instead, stabilize phase separation by partitioning into liquid-disordered domains and excluding cholesterol from the disordered domains. We predict that relatively small concentrations of hydrophobic species can have a broad impact on domain stability in model systems, which suggests possible mechanisms of action for hydrophobic compounds in vivo. PMID:25299598

  3. Membrane Bioreactor With Pressure Cycle

    NASA Technical Reports Server (NTRS)

    Efthymiou, George S.; Shuler, Michael L.

    1991-01-01

    Improved class of multilayer membrane bioreactors uses convention forced by differences in pressure to overcome some of diffusional limitations of prior bioreactors. In reactor of new class, flow of nutrient solution reduces adverse gradients of concentration, keeps cells supplied with fresh nutrient, and sweeps away products faster than diffusion alone. As result, overall yield and rate of reaction increased. Pressures in sweeping gas and nutrient alternated to force nutrient liquid into and out of biocatalyst layer through hyrophilic membrane.

  4. CENTRIFUGAL MEMBRANE FILTRATION

    SciTech Connect

    William A. Greene; Patricia A. Kirk; Richard Hayes; Joshua Riley

    2005-10-28

    SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, has engineered and developed a system for use within the U.S. Department of Energy (DOE) Environmental Management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. SpinTek II High Shear Rotary Membrane Filtration System is a unique compact crossflow membrane system that has large, demonstrable advantages in performance and cost compared to currently available systems: (1) High fluid shear prevents membrane fouling even with very high solids content; hazardous and radioactive components can be concentrated to the consistency of a pasty slurry without fouling. (2) Induced turbulence and shear across the membrane increases membrane flux by a factor of ten over existing systems and allows operation on fluids not otherwise treatable. (3) Innovative ceramic membrane and mechanical sealing technology eliminates compatibility problems with aggressive DOE waste streams. (4) System design allows rapid, simple disassembly for inspection or complete decontamination. (5) Produces colloidal- and suspended-solids-free filtrate without the addition of chemicals. The first phase of this project (PRDA maturity stage 5) completed the physical scale-up of the SpinTek unit and verified successful scale-up with surrogate materials. Given successful scale-up and DOE concurrence, the second phase of this project (PRDA maturity stage 6) will provide for the installation and

  5. Calibrating the X-ray attenuation of liquid water and correcting sample movement artefacts during in operando synchrotron X-ray radiographic imaging of polymer electrolyte membrane fuel cells.

    PubMed

    Ge, Nan; Chevalier, Stéphane; Hinebaugh, James; Yip, Ronnie; Lee, Jongmin; Antonacci, Patrick; Kotaka, Toshikazu; Tabuchi, Yuichiro; Bazylak, Aimy

    2016-03-01

    Synchrotron X-ray radiography, due to its high temporal and spatial resolutions, provides a valuable means for understanding the in operando water transport behaviour in polymer electrolyte membrane fuel cells. The purpose of this study is to address the specific artefact of imaging sample movement, which poses a significant challenge to synchrotron-based imaging for fuel cell diagnostics. Specifically, the impact of the micrometer-scale movement of the sample was determined, and a correction methodology was developed. At a photon energy level of 20 keV, a maximum movement of 7.5 µm resulted in a false water thickness of 0.93 cm (9% higher than the maximum amount of water that the experimental apparatus could physically contain). This artefact was corrected by image translations based on the relationship between the false water thickness value and the distance moved by the sample. The implementation of this correction method led to a significant reduction in false water thickness (to ∼0.04 cm). Furthermore, to account for inaccuracies in pixel intensities due to the scattering effect and higher harmonics, a calibration technique was introduced for the liquid water X-ray attenuation coefficient, which was found to be 0.657 ± 0.023 cm(-1) at 20 keV. The work presented in this paper provides valuable tools for artefact compensation and accuracy improvements for dynamic synchrotron X-ray imaging of fuel cells.

  6. Impact of food to microorganism (F/M) ratio and colloidal chemical oxygen demand on nitrification performance of a full-scale membrane bioreactor treating thin film transistor liquid crystal display wastewater.

    PubMed

    Wu, Yi-Ju; Whang, Liang-Ming; Chang, Ming-Yu; Fukushima, Toshikazu; Lee, Ya-Chin; Cheng, Sheng-Shung; Hsu, Shu-Fu; Chang, Cheng-Huey; Shen, Wason; Yang, Charn-Yi; Fu, Ryan; Tsai, Tsair-Yuan

    2013-08-01

    This study investigated impact of food to microorganism (F/M) ratio and colloidal chemical oxygen demand (COD) on nitrification performance in one full-scale membrane bioreactor (MBR) treating monoethanolamine (MEA)/dimethyl sulfoxide (DMSO)-containing thin film transistor liquid crystal display (TFT-LCD) wastewater. Poor nitrification was observed under high organic loading and high colloidal COD conditions, suggesting that high F/M ratio and colloidal COD situations should be avoided to minimize their negative impacts on nitrification. According to the nonmetric multidimensional scaling (NMS) statistical analyses on terminal restriction fragment length polymorphism (T-RFLP) results of ammonia monooxygenase (amoA) gene, the occurrence of Nitrosomonas oligotropha-like ammonia oxidizing bacteria (AOB) was positively related to successful nitrification in the MBR systems, while Nitrosomonas europaea-like AOB was positively linked to nitrification rate, which can be attributed to the high influent total nitrogen condition. Furthermore, Nitrobacter- and Nitrospira-like nitrite oxidizing bacteria (NOB) were both abundant in the MBR systems, but the continuously low nitrite environment is likely to promote the growth of Nitrospira-like NOB.

  7. Immobilized fluid membranes for gas separation

    SciTech Connect

    Liu, Wei; Canfield, Nathan L; Zhang, Jian; Li, Xiaohong Shari; Zhang, Jiguang

    2014-03-18

    Provided herein are immobilized liquid membranes for gas separation, methods of preparing such membranes and uses thereof. In one example, the immobilized membrane includes a porous metallic host matrix and an immobilized liquid fluid (such as a silicone oil) that is immobilized within one or more pores included within the porous metallic host matrix. The immobilized liquid membrane is capable of selective permeation of one type of molecule (such as oxygen) over another type of molecule (such as water). In some examples, the selective membrane is incorporated into a device to supply oxygen from ambient air to the device for electrochemical reactions, and at the same time, to block water penetration and electrolyte loss from the device.

  8. Multicomponent membranes

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

  9. Membrane Based Thermal Control Development

    NASA Technical Reports Server (NTRS)

    Murdoch, Karen

    1997-01-01

    The investigation of the feasibility of using a membrane device as a water boiler for thermal control is reported. The membrane device permits water vapor to escape to the vacuum of space but prevents the loss of liquid water. The vaporization of the water provides cooling to the water loop. This type of cooling device would have application for various types of short duration cooling needs where expenditure of water is allowed and a low pressure source is available such as in space or on a planet's surface. A variety of membrane samples, both hydrophilic and hydrophobic, were purchased to test for this thermal control application. An initial screening test determined if the membrane could pose a sufficient barrier to maintain water against vacuum. Further testing compared the heat transfer performance of those membranes that passed the screening test.

  10. Membrane technology comes of age

    SciTech Connect

    Dietrich, J.A.

    1995-07-01

    Membrane technology has come of age for industry, paralleling the increased pressures to recover products, recycle wastewater and minimize the volume, costs and liability associated with waste disposal. But, the conventional microfiltration/ultrafiltration/nanofiltration/reverse-osmosis breakout is only a starting point in determining whether membrane technology is a viable alternative in any given application. Membranes are distinguished not only by their pore size and molecular weight break-off points, but by their configurations and materials of construction. The efficiency of a particular membrane design relies, first and foremost, on an accurate understanding of the goals and objectives of the system. As waste disposal becomes an increasingly difficult and costly operation, the search for ways to recover usable products, recycle process liquids, and reduce the amounts of waste requiring disposal intensifies. For many of those goals, membrane technology offers options that are effective, dependable and increasingly cost-effective.

  11. Ultrathin self-assembled polyelectrolyte multilayer membranes

    NASA Astrophysics Data System (ADS)

    Tieke, B.; van Ackern, F.; Krasemann, L.; Toutianoush, A.

    The paper is concerned with ultrathin membranes prepared upon alternating layer-by-layer adsorption of cationic and anionic polyelectrolytes on a porous substructure. The formation of the polyelectrolyte multilayer membranes is characterised and the transport of gases, liquid mixtures and ions across the membranes is studied. In particular, the use of the membranes for alcohol/water separation under pervaporation conditions, and for the separation of mono- and divalent ions is described. It is demonstrated that upon a suitable choice of polyelectrolytes and substructures, and a careful optimisation of preparation and operation conditions, membranes can be tailored exhibiting an excellent separation capability.

  12. Centrifugal membrane filtration -- Task 9

    SciTech Connect

    1996-08-01

    The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, to demonstrate applications for the SpinTek technology within the US Department of Energy (DOE) Environmental management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. Membrane-screening tests were performed with the SpinTek STC-X4 static test cell filtration unit, using five ceramic membranes with different pore size and composition. Based on permeate flux, a 0.25-{micro}m TiO{sub 2}/Al{sub 2}O{sub 3} membrane was selected for detailed performance evaluation using the SpinTek ST-IIL centrifugal membrane filtration unit with a surrogate tank waste solution. An extended test run of 100 hr performed on a surrogate tank waste solution showed some deterioration in filtration performance, based on flux, apparently due to the buildup of solids near the inner portion of the membrane where relative membrane velocities were low. Continued testing of the system will focus on modifications to the shear pattern across the entire membrane surface to affect improved long-term performance.

  13. Enhancing CO2 Capture using Robust Superomniphobic Membranes.

    PubMed

    Geyer, Florian; Schönecker, Clarissa; Butt, Hans-Jürgen; Vollmer, Doris

    2017-02-01

    Superomniphobic membranes for post-combustion CO2 capture are introduced. Concentrated aqueous amine solutions stay on the topmost part of the membranes, providing a large liquid/CO2 interface. Wetting of the membrane, which reduces the capture efficiency, is prevented. The CO2 capture rates using the chemically, mechanically, and thermally stable superomniphobic membranes are enhanced by up to 40% relative to commercial membranes.

  14. Defect-free ultrahigh flux asymmetric membranes

    DOEpatents

    Pinnau, Ingo; Koros, William J.

    1990-01-01

    Defect-free, ultrahigh flux integrally-skinned asymmetric membranes having extremely thin surface layers (<0.2 .mu.m) comprised of glassy polymers are disclosed. The membranes are formed by casting an appropriate drope followed by forced convective evaporation of solvent to obtain a dry phase separated asymmetrical structure. The structure is then washed in a precipitation liquid and dried.

  15. MEMBRANE BIOTREATMENT OF VOC-LADEN AIR

    EPA Science Inventory

    The paper discusses membrane biotreatment of air laden with volatile organic compounds (VOCs). Microporous flat-sheet and hollow-fiber membrane contactors were used to support air-liquid mass transfer interfaces. These modules were used in a two-step process to transfer VOCs fr...

  16. Membrane evaporator/sublimator investigation

    NASA Technical Reports Server (NTRS)

    Elam, J.; Ruder, J.; Strumpf, H.

    1974-01-01

    Data are presented on a new evaporator/sublimator concept using a hollow fiber membrane unit with a high permeability to liquid water. The aim of the program was to obtain a more reliable, lightweight and simpler Extra Vehicular Life Support System (EVLSS) cooling concept than is currently being used.

  17. Propagation of a viscous thin film over an elastic membran

    NASA Astrophysics Data System (ADS)

    Zheng, Zhong; Griffiths, Ian; Stone, Howard

    2016-11-01

    We study the buoyancy-driven spreading of a thin viscous film over a thin elastic membrane. Neglecting the effects of membrane bending and the membrane weight, we study the case of constant fluid injection and obtain a system of coupled partial differential equations to describe the shape of the air-liquid interface, and the deformation and the radial tension of the stretched membrane. We obtain self-similar solutions to describe the dynamics. In particular, in the early time period, the dynamics is dominated by buoyancy-driven spreading of the liquid film, and membrane stretching is a response to the buoyancy-controlled distribution of liquid weight; the location of the liquid front obeys the power-law form rf (t) t 1 / 2 . However, in the late time period, the system is quasi-steady, the air-liquid interface is flat, and membrane stretching, due to the liquid weight, causes the spreading of the liquid front; the location of the front obeys a different power-law form rf (t) t 1 / 4 before the edge effects of the membrane become significant. In addition, we report laboratory experiments for constant fluid injection using different viscous liquids and thin elastic membranes. Very good agreement is obtained between the theory and experiments.

  18. Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

    NASA Astrophysics Data System (ADS)

    Li, Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

    2005-07-01

    Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance.

  19. MS-H: A Novel Proteomic Approach to Isolate and Type the E. coli H Antigen Using Membrane Filtration and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

    PubMed Central

    Cheng, Keding; Drebot, Mike; McCrea, Joanne; Peterson, Lorea; Lee, David; McCorrister, Stuart; Nickel, Richard; Gerbasi, Alyssia; Sloan, Angela; Janella, Debra; Van Domselaar, Gary; Beniac, Daniel; Booth, Tim; Chui, Linda; Tabor, Helen; Westmacott, Garrett; Gilmour, Matthew; Wang, Gehua

    2013-01-01

    Serotyping is the long-standing gold standard method to determine E. coli H antigens; however, this method requires a panel of H-antigen specific antibodies and often culture-based induction of the H-antigen flagellar motility. In this study, a rapid and accurate method to isolate and identify the Escherichia coli (E. coli) H flagellar antigen was developed using membrane filtration and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Flagella were isolated from pure culture, digested with trypsin, and then subjected to LC-MS/MS using one of two systems (Agilent-nano-LC-QSTAR XL or Proxeon-nano-LC-LTQ-Orbitrap XL). The resulting peptide sequence data were searched against a custom E. coli flagella/H antigen database. This approach was evaluated using flagella isolated from reference E. coli strains representing all 53 known H antigen types and 41 clinical E. coli strains. The resulting LC-MS/MS classifications of H antigen types (MS-H) were concordant with the known H serogroup for all 53 reference types, and of 41 clinical isolates tested, 38 (92.7%) were concordant with the known H serogroup. MS-H clearly also identified two clinical isolates (4.9%) that were untypeable by serotyping. Notably, successful detection and classification of flagellar antigens with MS-H did not generally require induction of motility, establishing this proteomic approach as more rapid and cost-effective than traditional methods, while providing equitable specificity for typing E. coli H antigens. PMID:23437374

  20. MS-H: a novel proteomic approach to isolate and type the E. coli H antigen using membrane filtration and liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    PubMed

    Cheng, Keding; Drebot, Mike; McCrea, Joanne; Peterson, Lorea; Lee, David; McCorrister, Stuart; Nickel, Richard; Gerbasi, Alyssia; Sloan, Angela; Janella, Debra; Van Domselaar, Gary; Beniac, Daniel; Booth, Tim; Chui, Linda; Tabor, Helen; Westmacott, Garrett; Gilmour, Matthew; Wang, Gehua

    2013-01-01

    Serotyping is the long-standing gold standard method to determine E. coli H antigens; however, this method requires a panel of H-antigen specific antibodies and often culture-based induction of the H-antigen flagellar motility. In this study, a rapid and accurate method to isolate and identify the Escherichia coli (E. coli) H flagellar antigen was developed using membrane filtration and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Flagella were isolated from pure culture, digested with trypsin, and then subjected to LC-MS/MS using one of two systems (Agilent-nano-LC-QSTAR XL or Proxeon-nano-LC-LTQ-Orbitrap XL). The resulting peptide sequence data were searched against a custom E. coli flagella/H antigen database. This approach was evaluated using flagella isolated from reference E. coli strains representing all 53 known H antigen types and 41 clinical E. coli strains. The resulting LC-MS/MS classifications of H antigen types (MS-H) were concordant with the known H serogroup for all 53 reference types, and of 41 clinical isolates tested, 38 (92.7%) were concordant with the known H serogroup. MS-H clearly also identified two clinical isolates (4.9%) that were untypeable by serotyping. Notably, successful detection and classification of flagellar antigens with MS-H did not generally require induction of motility, establishing this proteomic approach as more rapid and cost-effective than traditional methods, while providing equitable specificity for typing E. coli H antigens.

  1. Improved Traps for Removing Gases From Coolant Liquids

    NASA Technical Reports Server (NTRS)

    Holladay, John; Ritchie, Stephen

    2006-01-01

    Two documents discuss improvements in traps for removing noncondensable gases (e.g., air) from heat-transfer liquids (e.g., water) in spacecraft cooling systems. Noncondensable gases must be removed because they can interfere with operation. A typical trap includes a cylindrical hydrophobic membrane inside a cylindrical hydrophilic membrane, all surrounded by an outer cylindrical impermeable shell. The input mixture of gas bubbles and liquid flows into the annular volume between the membranes. Bubbles pass into the central hollow of the hydrophobic membrane and are vented. The liquid flows outward through the hydrophilic membrane and is recirculated.

  2. Possibilities of sterilization by track membranes

    NASA Astrophysics Data System (ADS)

    Kudoyarov, M. F.; Vishnevskii, B. I.; Manicheva, O. A.; Myakotina, E. N.; Mukhin, S. A.; Patrova, M. Ya.; Vedmetskii, Yu. V.

    2011-09-01

    The possibility of using track membranes for the dimensional separation of Mycobacterium tuberculosis (MBT) species from liquid media has been studied. A set of track membranes with various pore diameters was prepared at the accelerator complex of the Ioffe Physical Technical Institute (St. Petersburg) and all samples were tested for their ability to separate MBT species of 13 strains from solutions. The results showed high ability of the track membranes with pore diameters from 180 to 300 nm to sterilize liquid media and confirmed the hypothesis concerning relatively high rigidity of these bacteria.

  3. Membrane permeation employed for radioactive wastes treatment

    SciTech Connect

    Chmielewski, A.G.; Harasimowicz, M.; Zakrzewska-Trznadel, G.

    1996-12-31

    In the paper certain aspects of development process aiming at reducing the radioactivity of liquid low-level waste streams (LLLW) are presented. The influence of gamma and electron radiation on ultrafiltration membranes has been studied and changes of their transport properties have been determined at different doses. Membrane processes: ultrafiltration (UF), seeded ultrafiltration (SUF), low-pressure reverse osmosis (LPRO) and membrane distillation (MD) have been examined. The UF/RO pilot plant for purification/concentration of low-level liquid waste is described. 4 refs., 2 figs.

  4. Crystalline Membranes

    NASA Technical Reports Server (NTRS)

    Tsapatsis, Michael (Inventor); Lai, Zhiping (Inventor)

    2008-01-01

    In certain aspects, the invention features methods for forming crystalline membranes (e.g., a membrane of a framework material, such as a zeolite) by inducing secondary growth in a layer of oriented seed crystals. The rate of growth of the seed crystals in the plane of the substrate is controlled to be comparable to the rate of growth out of the plane. As a result, a crystalline membrane can form a substantially continuous layer including grains of uniform crystallographic orientation that extend through the depth of the layer.

  5. Biological membranes

    PubMed Central

    Watson, Helen

    2015-01-01

    Biological membranes allow life as we know it to exist. They form cells and enable separation between the inside and outside of an organism, controlling by means of their selective permeability which substances enter and leave. By allowing gradients of ions to be created across them, membranes also enable living organisms to generate energy. In addition, they control the flow of messages between cells by sending, receiving and processing information in the form of chemical and electrical signals. This essay summarizes the structure and function of membranes and the proteins within them, and describes their role in trafficking and transport, and their involvement in health and disease. Techniques for studying membranes are also discussed. PMID:26504250

  6. Mass transfer in corrugated membranes

    NASA Astrophysics Data System (ADS)

    Gronda, Ann Mclaughry

    Research on the chemical and physical structure of membranes has failed to overcome the inverse relationship between selectivity and permeability. While this permeability is partially responsible for the rate of separation, the geometry of the membrane contributes significantly to this rate. In this work, we focused on the system geometry by examining the effect of corrugations on the rate of membrane separations. We developed a theory to describe mass transport in corrugations and to predict the effectiveness of corrugated membranes. To verify this theory, membranes with millimeter-sized corrugations were made. Pervaporation experiments with highly permeable and less permeable solutes showed excellent agreement with the theory. Based on the membrane geometry and permeability, the effectiveness factor and the flux enhancement can be quantified by a modified Thiele analysis. We used this theory to examine the effect of small corrugations on the mass transfer of both liquids and gases across membranes, including the effects of free convection, membrane supports, and Knudsen diffusion. In systems with a liquid feed, corrugations are promising only for very impermeable solutes. In gases, corrugations are more effective, especially when supported by a porous structure. We attempted to make smaller corrugations in two ways. The more promising method is phase-inversion of diblock copolymers. These diblocks were dissolved in a solvent, made into a thin film, and immersed in a liquid that was a nonsolvent for the majority block and a solvent for the minority block. In this way, we attempted to draw the minority block to the surface of an undulating structure created by the phase inversion. Ideally, the minority block would be selective and the majority block would be highly permeable or porous. Scanning electron microscopy showed promising structures made from polystyrene-polyisoprene and polyacrylonitrile-polyethylene oxide. The other, less promising, attempt at making

  7. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  8. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  9. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  10. 21 CFR 173.21 - Perfluorinated ion exchange membranes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Perfluorinated ion exchange membranes. 173.21... ion exchange membranes. Substances identified in paragraph (a) of this section may be safely used as ion exchange membranes intended for use in the treatment of bulk quantities of liquid food under...

  11. Do local anesthetics interact preferentially with membrane lipid rafts? Comparative interactivities with raft-like membranes.

    PubMed

    Tsuchiya, Hironori; Ueno, Takahiro; Mizogami, Maki; Takakura, Ko

    2010-08-01

    Membranous lipid bilayers have been reconsidered as the site of action of local anesthetics (LAs). Recent understanding of biomembranes indicates the existence of lipid raft microdomains enriched in cholesterol and sphingolipids as potential platforms for channels and receptors. Based on the hypothesis that LAs may interact preferentially with lipid rafts over non-raft membranes, we compared their effects on raft model membranes and cardiolipin-containing biomimetic membranes. Liposomes were prepared with phospholipids, sphingomyelin, cerebroside, and cholesterol to have compositions corresponding to lipid rafts and cardiomyocyte mitochondrial membranes. After reacting LAs (50-200 microM) with the membrane preparations, their interactivities were determined by measuring fluorescence polarization with 1,6-diphenyl-1,3,5-hexatriene. Although bupivacaine and lidocaine acted on different raft-like liquid-ordered membranes to reduce polarization values, their effects on biomimetic less ordered membranes were much greater. LAs interacted with biomimetic membranes with the potency being R(+)-bupivacaine > racemic bupivacaine > S(-)-bupivacaine > ropivacaine > lidocaine > prilocaine, which is consistent with the rank order of pharmacotoxicological potency. However, raft model membranes showed neither structure-dependence nor stereoselectivity. The relevance of membrane lipid rafts to LAs is questionable at least in their effects on raft-like liquid-ordered membranes.

  12. Active microrheology of smectic membranes.

    PubMed

    Qi, Zhiyuan; Ferguson, Kyle; Sechrest, Yancey; Munsat, Tobin; Park, Cheol Soo; Glaser, Matthew A; Maclennan, Joseph E; Clark, Noel A; Kuriabova, Tatiana; Powers, Thomas R

    2017-02-01

    Thin fluid membranes embedded in a bulk fluid of different viscosity are of fundamental interest as experimental realizations of quasi-two-dimensional fluids and as models of biological membranes. We have probed the hydrodynamics of thin fluid membranes by active microrheology using small tracer particles to observe the highly anisotropic flow fields generated around a rigid oscillating post inserted into a freely suspended smectic liquid crystal film that is surrounded by air. In general, at distances more than a few Saffman lengths from the meniscus around the post, the measured velocities are larger than the flow computed by modeling a moving disklike inclusion of finite extent by superposing Levine-MacKintosh response functions for pointlike inclusions in a viscous membrane. The observed discrepancy is attributed to additional coupling of the film with the air below the film that is displaced directly by the shaft of the moving post.

  13. Active microrheology of smectic membranes

    NASA Astrophysics Data System (ADS)

    Qi, Zhiyuan; Ferguson, Kyle; Sechrest, Yancey; Munsat, Tobin; Park, Cheol Soo; Glaser, Matthew A.; Maclennan, Joseph E.; Clark, Noel A.; Kuriabova, Tatiana; Powers, Thomas R.

    2017-02-01

    Thin fluid membranes embedded in a bulk fluid of different viscosity are of fundamental interest as experimental realizations of quasi-two-dimensional fluids and as models of biological membranes. We have probed the hydrodynamics of thin fluid membranes by active microrheology using small tracer particles to observe the highly anisotropic flow fields generated around a rigid oscillating post inserted into a freely suspended smectic liquid crystal film that is surrounded by air. In general, at distances more than a few Saffman lengths from the meniscus around the post, the measured velocities are larger than the flow computed by modeling a moving disklike inclusion of finite extent by superposing Levine-MacKintosh response functions for pointlike inclusions in a viscous membrane. The observed discrepancy is attributed to additional coupling of the film with the air below the film that is displaced directly by the shaft of the moving post.

  14. Inorganic membranes and solid state sciences

    NASA Astrophysics Data System (ADS)

    Cot, Louis; Ayral, André; Durand, Jean; Guizard, Christian; Hovnanian, Nadine; Julbe, Anne; Larbot, André

    2000-05-01

    The latest developments in inorganic membranes are closely related to recent advances in solid state science. Sol-gel processing, plasma-enhanced chemical vapor deposition and hydrothermal synthesis are methods that can be used for inorganic membrane preparation. Innovative concepts from material science (templating effect, nanophase materials, growing of continuous zeolite layers, hybrid organic-inorganic materials) have been applied by our group to the preparation of inorganic membrane materials. Sol-gel-derived nanophase ceramic membranes are presented with current applications in nanofiltration and catalytic membrane reactors. Silica membranes with an ordered porosity, due to liquid crystal phase templating effect, are described with potential application in pervaporation. Defect-free and thermally stable zeolite membranes can be obtained through an original synthesis method, in which zeolite crystals are grown inside the pores of a support. Hybrid organic-inorganic materials with permselective properties for gas separation and facilitated transport of solutes in liquid media, have been successfully adapted to membrane applications. Potential membrane developments offered by CVD deposition techniques are also illustrated through several examples related to the preparation of purely inorganic and hybrid organic-inorganic membrane materials.

  15. Photo-switchable membrane and method

    DOEpatents

    Marshall, Kenneth L; Glowacki, Eric

    2013-05-07

    Switchable gas permeation membranes in which a photo-switchable low-molecular-weight liquid crystalline (LC) material acts as the active element, and a method of making such membranes. Different LC eutectic mixtures were doped with mesogenic azo dyes and infused into track-etched porous membranes with regular cylindrical pores. Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photo-switchable membrane to nitrogen. For example, membranes imbibed with a photo-switchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photo-generated isotropic state demonstrated a 16.times.-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. In contrast, membranes imbibed with a photo-switchable phenyl benzoate LC material showed the opposite permeability behavior to the biphenyl-imbibed membrane, along with nonlinear sorption behavior.

  16. Lipid exchange between membranes: effects of membrane surface charge, composition, and curvature.

    PubMed

    Zhu, Tao; Jiang, Zhongying; Ma, Yuqiang

    2012-09-01

    Intermembrane lipid exchange is critical to membrane functions and pharmaceutical applications. The exchange process is not fully understood and it is explored by quartz crystal microbalance with dissipation monitor method in this research. It is found that intermembrane lipid exchange is accelerated with the decrease of vesicle size and the increase of charge and liquid crystalline lipid composition ratio. Vesicle adsorption rate, membrane lateral pressure gradient, and lipid lateral diffusion coefficient are inferred to be critical in deciding the lipid exchange kinetics between membranes. Besides that, the membrane contact situation during lipid exchange is also studied. The maximum total membrane contact area is found to increase with the decrease of vesicle size, charged and liquid crystalline lipid composition ratio. A competition mechanism between the vesicle adsorption rate and the intermembrane lipid exchange rate was proposed to control the maximum total membrane contact area.

  17. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    NASA Technical Reports Server (NTRS)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  18. OXYGEN TRANSPORT CERAMIC MEMBRANES

    SciTech Connect

    Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

    2001-12-01

    Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

  19. Cholesterol Mediates Membrane Curvature during Fusion Events

    NASA Astrophysics Data System (ADS)

    Ivankin, Andrey; Kuzmenko, Ivan; Gidalevitz, David

    2012-06-01

    Biomembranes undergo extensive shape changes as they perform vital cellular functions. The mechanisms by which lipids and proteins control membrane curvature remain unclear. We use x-ray reflectivity, grazing incidence x-ray diffraction, and epifluorescence microscopy to study binding of HIV-1 glycoprotein gp41’s membrane-bending domain to DPPC/cholesterol monolayers of various compositions at the air-liquid interface. The results offer a new insight into how membrane curvature could be regulated by cholesterol during fusion of the viral lipid envelope and the host cell membranes.

  20. Membranes for Environmentally Friendly Energy Processes

    PubMed Central

    He, Xuezhong; Hägg, May-Britt

    2012-01-01

    Membrane separation systems require no or very little chemicals compared to standard unit operations. They are also easy to scale up, energy efficient, and already widely used in various gas and liquid separation processes. Different types of membranes such as common polymers, microporous organic polymers, fixed-site-carrier membranes, mixed matrix membranes, carbon membranes as well as inorganic membranes have been investigated for CO2 capture/removal and other energy processes in the last two decades. The aim of this work is to review the membrane systems applied in different energy processes, such as post-combustion, pre-combustion, oxyfuel combustion, natural gas sweetening, biogas upgrading, hydrogen production, volatile organic compounds (VOC) recovery and pressure retarded osmosis for power generati