Science.gov

Sample records for membranes liquides supportees

  1. Experimenting with Liquid Membranes.

    ERIC Educational Resources Information Center

    Lamb, J. D.; And Others

    1980-01-01

    Outlined are two experiments using liquid membranes that illustrate carrier-facilitated transport, where chemical species are ushered across the membrane by selective "carrier" molecules residing in the membrane. The use of liquid membranes as models for studying and describing biological transport mechanisms is explored. (CS)

  2. Supported liquid membranes

    SciTech Connect

    Danesi, P.R.

    1984-01-01

    The possibility of utilizing thin layers of organic solutions of solvent extraction reagents, immobilized on microporous inert supports interposed between two aqueous solutions, for selectively removing metal ions from a mixture represents an attractive alternative to liquid-liquid extraction. A detailed knowledge of the liquid-liquid extraction equilibria and mass transfer kinetics is required to understand and to describe quantitatively the rate laws which control the permeation of metal species through Supported Liquid Membranes (SLM) and to exploit them for separation processes. This paper attempts to understand the mechanism of transport through SLM.

  3. Supported liquid membrane system

    SciTech Connect

    Takigawa, D.Y.; Bush, H. Jr.

    1990-12-31

    A cell apparatus for a supported liquid membrane including opposing faceplates, each having a spirally configured groove, an inlet groove at a first end of the spirally configured groove, and an outlet groove at the other end of the spirally configured groove, within the opposing faces of the faceplates, a microporous membrane situated between the grooved faces of the faceplates, said microporous membrane containing an extractant mixture selective for a predetermined chemical species within the pores of said membrane, means for aligning the grooves of the faceplates in an directly opposing configuration with the porous membrane being situated therebetween, such that the aligned grooves form a pair of directly opposing channels, separate feed solution and stripping solution compartments connected to respective channels between the faceplates and the membrane, separate pumping means for passing feed solution and stripping solution through the channels is provided.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Phenol removal by supported liquid membranes

    SciTech Connect

    Zha, F.F.; Fane, A.G.; Fell, C.J.D.

    1994-11-01

    This paper examines the application of the supported liquid membrane (SLM) to phenol removal. n-Decanol was proven to be a suitable membrane liquid. The phenol transfer kinetics through the SLMs is quantitatively estimated according to models based on the resistance-in-series concept. The models can be modified to describe the performance of decayed SLMs and thereby provide insight into the effect of membrane liquid loss and penetration of aqueous solutions on the phenol flux. An experimental method is described for the measurement of mass transfer coefficients in the bulk phases using the well-characterized Anopore membrane.

  9. Membrane separation of ionic liquid solutions

    SciTech Connect

    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.

  10. 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.

  11. Supported Ionic Liquid Membranes for Gas Separation

    SciTech Connect

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

    2007-08-01

    Ionic liquids have been rapidly gaining attention for various applications including solvent separation and gas capture. These substances are noted for extremely low vapor pressure and high CO2 solubility making them ideal as transport or capture media for CO2 abatement in power generation applications. Ionic liquids, combined with various supports to form membranes, have been proven selective in CO2 separation. Several ionic liquids and a variety of polymer supports have been studied over a temperature range from 37°C to 300°C and have been optimized for stability. The membranes have demonstrated high permeability and high selectivity since the supported ionic liquid membranes incorporate functionality capable of chemically complexing CO2. A study aimed at improving supported ionic liquid membranes will examine their durability with greater transmembrane pressures and the effects on CO2 permeance, CO2/H2 selectivity and thermal stability.

  12. 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.

  13. 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.

  14. 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.

  15. Polymer single crystal membrane from liquid/liquid interface

    NASA Astrophysics Data System (ADS)

    Wang, Wenda; Li, Christopher; Soft Matter Research Group-Drexel University Team

    2013-03-01

    Vesicles, mimicking the structure of cell membrane at the molecular scale, are small membrane-enclosed sacks that can store or transport substances. The weak mechanical properties and the nature of environment-sensitivity of the current available vesicles: liposomes, polymersomes, colloidsomes limit their applications as an excellent candidate for targeting delivery of drugs/genes in biomedical engineering and treatment. Recently, we developed an emulsion-based method to grow curved polymer single crystals. Varying the polymer concentration and/or the emulsification conditions (such as surfactant concentration, water-oil volume ratio), curved crystals with different sizes and different openness could be obtained. This growing process was attributed to polymer crystal growth along the liquid/liquid interface. In addition, the liquid/liquid interfacial crystal growth is promising for synthesis of enclosed hollow sphere.

  16. 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)

  17. Analytical Applications of Transport Through Bulk Liquid Membranes.

    PubMed

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

    2016-07-01

    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. Developments in liquid membrane separation of beta-lactam antibiotics.

    PubMed

    Ghosh, A C; Bora, M M; Dutta, N N

    1996-04-01

    This paper presents an overview on the developments in liquid membrane separation and purification of commercially important beta-lactam antibiotics. Reactive extraction via liquid-liquid ion exchange or ion-pair extraction mechanism can be exploited to develop liquid membrane processes for separation and concentration of penicillins and cephalosporins. Because of high selectivity and flux, liquid membrane processes can be adopted for direct extraction of beta-lactams from fermentation broth. Other advantages of liquid membrane technologies are low capital and operating costs, compact unit installation in commercial plants, low material inventory, etc. Both emulsion liquid membrane and supported liquid membrane techniques can be effective under the reactive extraction conditions. However, the stability problems of liquid membrane should be resolved before commercial application can be established. Alternately, reactive extraction in non-dispersive mode with hollow fiber membranes can be an attractive and viable strategy for practical application. Applicability of the liquid membrane processes has been discussed from process engineering and design considerations.

  20. Supported liquid membrane battery separators. Final report

    SciTech Connect

    Pemsler, J.P.; Dempsey, M.D.

    1984-07-01

    This study was performed to explore the feasibility of using a supported liquid membrane (SLM) as a separator in the nickel-zinc battery. In particular, SLM separators should prevent zinc dendrite growth from shorting out the cell and might also alleviate capacity loss due to zinc electrode shape changes. A number of ion exchange/solvent modifier systems for incorporation into SLMs were developed under a previous LBL contract. SLMs prepared with these reagents exhibited resistances in the range of 0.4 to 10 ohm cm/sup 2/, selectively transported hydroxyl ions over zincate ions by a factor of 10/sup 6/ to 10/sup 7/, and possessed eletrochemical and chemical stability in alkaline electrolytes. In order to evaluate these SLM separators under conditions closely resembling a commercial Ni-Zn cell, an accelerated cycle life test was devised using commercial electrodes.

  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 be also investigated.

  2. 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.

  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. 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.

  5. 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)

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

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

    2007-05-01

    A practical form of CO2 capture at water-gas shift conditions in the IGCC process could serve the dual function of producing a pure CO2 stream for sequestration and forcing the equilibrium-limited shift reaction to completion enriching the stream in H2. The shift temperatures, ranging from the low temperature shift condition of 260°C to the gasification condition of 900°C, limit capture options by diminishing associative interactions which favor removal of CO2 from the gas stream. Certain sorption interactions, such as carbonate formation, remain available but generally involve exceptionally high sorbent regeneration energies that contribute heavily to parasitic power losses. Carbon dioxide selective membranes need only establish an equilibrium between the gas phase and sorption states in order to transport CO2, giving them a potential energetic advantage over other technologies. Supported liquid membranes take advantage of high, liquid phase diffusivities and a solution diffusion mechanism similar to that observed in polymeric membranes to achieve superior permeabilities and selectivites. 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 CO2 solubility relative to light gases such as H2, are excellent candidates 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 ionic liquids including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide 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 the resulting materials for membrane

  13. 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.

  14. Supported liquid inorganic membranes for nuclear waste separation

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

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

    DOEpatents

    Lin, Yupo J.; Snyder, Seth W.

    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.

  2. 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.

  3. 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.

  4. 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

  5. Membrane Treatment of Liquid Salt Bearing Radioactive Wastes

    SciTech Connect

    Dmitriev, S. A.; Adamovich, D. V.; Demkin, V. I.; Timofeev, E. M.

    2003-02-25

    The main fields of introduction and application of membrane methods for preliminary treatment and processing salt liquid radioactive waste (SLRW) can be nuclear power stations (NPP) and enterprises on atomic submarines (AS) utilization. Unlike the earlier developed technology for the liquid salt bearing radioactive waste decontamination and concentrating this report presents the new enhanced membrane technology for the liquid salt bearing radioactive waste processing based on the state-of-the-art membrane unit design, namely, the filtering units equipped with the metal-ceramic membranes of ''TruMem'' brand, as well as the electrodialysis and electroosmosis concentrators. Application of the above mentioned units in conjunction with the pulse pole changer will allow the marked increase of the radioactive waste concentrating factor and the significant reduction of the waste volume intended for conversion into monolith and disposal. Besides, the application of the electrodialysis units loaded with an ion exchange material at the end polishing stage of the radioactive waste decontamination process will allow the reagent-free radioactive waste treatment that meets the standards set for the release of the decontaminated liquid radioactive waste effluents into the natural reservoirs of fish-farming value.

  6. 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.

  7. On-line automated sample preparation for liquid chromatography using parallel supported liquid membrane extraction and microporous membrane liquid-liquid extraction.

    PubMed

    Sandahl, Margareta; Mathiasson, Lennart; Jönsson, Jan Ake

    2002-10-25

    An automated system was developed for analysis of non-polar and polar ionisable compounds at trace levels in natural water. Sample work-up was performed in a flow system using two parallel membrane extraction units. This system was connected on-line to a reversed-phase HPLC system for final determination. One of the membrane units was used for supported liquid membrane (SLM) extraction, which is suitable for ionisable or permanently charged compounds. The other unit was used for microporous membrane liquid-liquid extraction (MMLLE) suitable for uncharged compounds. The fungicide thiophanate methyl and its polar metabolites carbendazim and 2-aminobenzimidazole were used as model compounds. The whole system was controlled by means of four syringe pumps. While extracting one part of the sample using the SLM technique. the extract from the MMLLE extraction was analysed and vice versa. This gave a total analysis time of 63 min for each sample resulting in a sample throughput of 22 samples per 24 h.

  8. 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.

  9. Actinide separations by supported liquid membranes

    SciTech Connect

    Danesi, P.R.; Horwitz, E.P.; Rickert, P.; Chiarizia, R.

    1984-01-01

    The work has demonstrated that actinide removal from synthetic waste solutions using both flat-sheet and hollow-fiber SLM's is a feasible chemical process at the laboratory scale level. The process is characterized by the typical features of SLM's processes: very small quantities of extractant required; the potential for operations with high feed/strip volume ratios, resulting in a corresponding concentration factor of the actinides; and simplicity of operation. Major obstacles to the implementation of the SLM technology to the decontamination of liquid nuclear wastes are the probable low resistance of polypropylene supports to high radiation fields, which may prevent the application to high-level nuclear wastes; the unknown lifetime of the SLM; and the high Na content of the separated actinide solution.

  10. 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.

  11. 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

  12. 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.

  13. Thermoelectric Potential of Polymer-Scaffolded Ionic Liquid Membranes

    NASA Astrophysics Data System (ADS)

    Datta, R. S.; Said, S. M.; Sahamir, S. R.; Karim, M. R.; Sabri, M. F. M.; Nakajo, T.; Kubouchi, M.; Hayashi, K.; Miyazaki, Y.

    2014-06-01

    Organic thin films have been viewed as potential thermoelectric (TE) materials, given their ease of fabrication, flexibility, cost effectiveness, and low thermal conductivity. However, their intrinsically low electrical conductivity is a main drawback which results in a relatively lower TE figure of merit for polymer-based TE materials than for inorganic materials. In this paper, a technique to enhance the ion transport properties of polymers through the introduction of ionic liquids is presented. The polymer is in the form of a nanofiber scaffold produced using the electrospinning technique. These fibers were then soaked in different ionic liquids based on substituted imidazolium such as 1-ethyl-3-methylimidazolium chloride or 1-butyl-3-methylimidazolium bromide. This method was applied to electrospun polyacrylonitrile and a mixture of polyvinyl alcohol and chitosan polymers. The ion transport properties of the membranes have been observed to increase with increasing concentration of ionic liquid, with maximum electrical conductivity of 1.20 × 10-1 S/cm measured at room temperature. Interestingly, the maximum electrical conductivity value surpassed the value of pure ionic liquids. These results indicate that it is possible to significantly improve the electrical conductivity of a polymer membrane through a simple and cost-effective method. This may in turn boost the TE figures of merit of polymer materials, which are well known to be considerably lower than those of inorganic materials. Results in terms of the Seebeck coefficient of the membranes are also presented in this paper to provide an overall representation of the TE potential of the polymer-scaffolded ionic liquid membranes.

  14. 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%. PMID:22581655

  15. 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

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

    NASA Astrophysics Data System (ADS)

    Hoarfrost, Megan; Tyagi, Madhu; Reimer, Jeffrey; Segalman, Rachel

    2011-03-01

    Nanostructured block copolymer/ionic liquid mixtures are of interest for creating membranes having high proton conductivity coupled with high thermal stability. In these mixtures, it is anticipated that nanoconfinement to block copolymer domains will affect ionic liquid proton transport properties. Using pulsed-field gradient NMR and quasi-elastic neutron scattering, this relationship has been investigated for mixtures of poly(styrene-b- 2-vinylpyridine) (S2VP) with ionic liquids composed of imidazole and bis(trifluoromethane)sulfonimide (HTFSI), where the ionic liquids selectively reside in the P2VP domains of the block copolymer. Proton mobility is highest in the neat ionic liquids when there is an excess of imidazole compared to HTFSI due to proton hopping between hydrogen-bonded imidazoles. As predicted, the amount of proton hopping can be tuned by nanoconfinement, as evidenced by the finding that a lamellar mixture of an imidazole- excess ionic liquid with S2VP has greater proton mobility than a corresponding disordered mixture of the ionic liquid with P2VP homopolymer.

  17. 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

  18. GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

    SciTech Connect

    Howard S. Meyer

    2003-10-01

    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. A Haz

  19. 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.

  20. Planar equilibrium shapes of a liquid drop on a membrane.

    PubMed

    Hui, Chung-Yuen; Jagota, Anand

    2015-12-14

    The equilibrium shape of a small liquid drop on a smooth rigid surface is governed by the minimization of energy with respect to the change in configuration, represented by the well-known Young's equation. In contrast, the equilibrium shape near the line separating three immiscible fluid phases is determined by force balance, represented by Neumann's Triangle. These two are limiting cases of the more general situation of a drop on a deformable, elastic substrate. Specifically, we have analyzed planar equilibrium shapes of a liquid drop on a deformable membrane. We show that to determine its equilibrium shape one must simultaneously satisfy configurational energy and mechanical force balance along with a constraint on the liquid volume. The first condition generalizes Young's equation to include changes in stored elastic energy upon changing the configuration. The second condition generalizes the force balance conditions by relating tensions to membrane stretches via their constitutive elastic behavior. The transition from Young's equation to Neumann's triangle is governed by the value of the elasto-capillary number, β = TRo/μh, where TRo is twice the surface tension of the solid-vapor interface, μ is the shear modulus of the membrane, and h is its thickness.

  1. Patterns of Flexible Nanotubes Formed by Liquid-Ordered and Liquid-Disordered Membranes.

    PubMed

    Liu, Yonggang; Agudo-Canalejo, Jaime; Grafmüller, Andrea; Dimova, Rumiana; Lipowsky, Reinhard

    2016-01-26

    Biological membranes form both intra- and intercellular nanotubes that are used for molecular sorting within single cells and for long-distance connections between different cells. Such nanotubes can also develop from synthetic lipid bilayers in their fluid state. Each nanotube has a large area-to-volume ratio and stably encloses a water channel that is thereby shielded from its surroundings. The tubes are rather flexible and can easily change both their length and their conformation. Here, we study nanotubes formed by liquid-ordered (Lo) and liquid-disordered (Ld) membranes with three lipid components exposed to aqueous mixtures of two polymers, polyethylene glycol (PEG) and dextran. Both types of membranes form striking patterns of nanotubes when we reduce the volume of giant vesicles by osmotic deflation, thereby exposing the two bilayer leaflets of the membranes to polymer solutions of different composition. With decreasing volume, three different patterns are observed corresponding to three distinct vesicle morphologies that reflect the interplay of spontaneous curvature and aqueous phase separation. We show that tube nucleation and growth is governed by two kinetic pathways and that the tubes undergo a novel shape transformation from necklace-like to cylindrical tubes at a certain critical tube length. We deduce the spontaneous curvature generated by the membrane-polymer interactions from the observed vesicle morphologies using three different and independent methods of image analysis. The spontaneous curvature of the Ld membranes is found to be 4.7 times larger than that of the Lo membranes. We also show that these curvatures are generated by weak PEG adsorption onto the membranes, with a binding affinity of about 1.6 kBT per chain. In this way, our study provides a direct connection between nanoscopic membrane shapes and molecular interactions. Our approach is rather general and can be applied to many other systems of interest such as polymersomes or

  2. Two-dimensional materials for novel liquid separation membranes.

    PubMed

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

    2016-08-19

    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

  3. Two-dimensional materials for novel liquid separation membranes.

    PubMed

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

    2016-08-19

    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

  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. C. elegans uses Liquid-Liquid Demixing for the Assembly of Non-Membrane-Bound Compartments

    NASA Astrophysics Data System (ADS)

    Weber, Christoph A.; Juelicher, Frank; Diaz Delgadillo, Andres Felipe; Jawerth, Louise; Hyman, Anthony A.; Department Biological Physics Team; Hyman Lab Collaboration

    2015-03-01

    P granules are liquid cytoplasmic RNA/Protein condensates known to determine the germ lineage in Caenorhabditis elegans. They resemble striking similarities with liquid droplets, such as dripping, shearing and wetting. Assuming that P granules are liquid-like we consider how they form in the crowded cytoplasm. Using confocal and light-sheet microscopy, P granule formation in-vivo and in-vitro is shown to share all hallmarks with a liquid-liquid phase-separation. Specifically, demixing is determined by temperature and concentration, the droplet formation is reversible with respect to temperature quenches and there is evidence for droplet growth due to coalescence and Ostwald-ripening. Liquid-liquid demixing in-vivo breaks the paradigmatic view that a molecular machinery is necessary to build up organelles through complex biological pathways. Instead we propose that P granules form following a Flory-Huggins model. Liquid-liquid demixing could also serve as a mechanism for the assembly of non-membrane-bound compartments in other living organisms.

  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. 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.

  8. Liquid General Anesthetics Lower Critical Temperatures in Plasma Membrane Vesicles

    PubMed Central

    Gray, Ellyn; Karslake, Joshua; Machta, Benjamin B.; Veatch, Sarah L.

    2013-01-01

    A large and diverse array of small hydrophobic molecules induce general anesthesia. Their efficacy as anesthetics has been shown to correlate both with their affinity for a hydrophobic environment and with their potency in inhibiting certain ligand-gated ion channels. In this study we explore the effects that n-alcohols and other liquid anesthetics have on the two-dimensional miscibility critical point observed in cell-derived giant plasma membrane vesicles (GPMVs). We show that anesthetics depress the critical temperature (Tc) of these GPMVs without strongly altering the ratio of the two liquid phases found below Tc. The magnitude of this affect is consistent across n-alcohols when their concentration is rescaled by the median anesthetic concentration (AC50) for tadpole anesthesia, but not when plotted against the overall concentration in solution. At AC50 we see a 4°C downward shift in Tc, much larger than is typically seen in the main chain transition at these anesthetic concentrations. GPMV miscibility critical temperatures are also lowered to a similar extent by propofol, phenylethanol, and isopropanol when added at anesthetic concentrations, but not by tetradecanol or 2,6 diterbutylphenol, two structural analogs of general anesthetics that are hydrophobic but have no anesthetic potency. We propose that liquid general anesthetics provide an experimental tool for lowering critical temperatures in plasma membranes of intact cells, which we predict will reduce lipid-mediated heterogeneity in a way that is complimentary to increasing or decreasing cholesterol. Also, several possible implications of our results are discussed in the context of current models of anesthetic action on ligand-gated ion channels. PMID:24359747

  9. Citrate-based contained liquid membranes for flue gas desulfurization

    SciTech Connect

    Pakala, N.R.; Varanasi, S.; LeBlanc, S.E. )

    1993-03-01

    The steady-state SO[sub 2] fluxes across aqueous sodium citrate and sulfite films were measured, using a flat liquid film sandwiched between polymer sheets and also a hollow-fiber contained liquid membrane device (HFCLM). Nonequilibrium boundary layer analysis (NEBLA) for the transport of SO[sub 2] through sulfate films was modified for citrate films and compared to the experimental data. The agreement between the measured fluxes and model predictions is excellent. SO[sub 2] transport rates across citrate films were found to be higher by at least a factor of 4 compared to those across sulfite films, at all reagent concentrations studied. The observed enhancement in SO[sub 2] flux across aqueous sulfite or citrate films stems from the dynamic role played by these weak-acid reagents as carriers for H[sup +] ions across the film. A weak acid with a pK close to the arithmetic mean of the pH values at the two faces of the liquid film is expected to provide the maximum enhancement in SO[sub 2] flux.

  10. 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

  11. A polybenzimidazole/ionic-liquid-graphite-oxide composite membrane for high temperature polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Xu, Chenxi; Liu, Xiaoteng; Cheng, Jigui; Scott, Keith

    2015-01-01

    Graphite oxide is successfully functionalised by 3-aminopropyltriethoxysilane ionic liquid and used as a filler material in a polybenzimidazole (PBI) membrane for high temperature proton exchange membrane fuel cells. The ionic-liquid-graphite-oxide/polybenzimidazole (ILGO/PBI) composite membrane exhibits an appropriate level of proton conductivity when imbibed with phosphoric acid at low phosphoric acid loading, which promotes its use in fuel cells by avoiding acid leakage and materials corrosion. The ionic conductivities of the ILGO/PBI membranes at 175 °C are 0.035 S cm-1 and 0.025 S cm-1 at per repeat units of 3.5 and 2.0, respectively. The fuel cell performance of ILGO/PBI membranes exhibits a maximum power density of 320 mW cm-2 at 175 °C, which is higher than that of a pristine PBI membrane.

  12. Separation of metal species by supported liquid membranes

    SciTech Connect

    Danesi, P.R.

    1985-01-01

    The work performed in the Separation Chemistry Group of the Chemistry Division of Argonne National Laboratory on the transport and separation properties of supported liquid membranes (SLM) are reviewed. The models and equations which describe the permeation through SLMs of metal species are described. These models have been tested with various carriers absorbed on flat-sheet and hollow-fiber SLMs by measuring the permeation of several metal species of hydrometallurgical and nuclear interest. An equation for the separation factor of metal species in SLM processes and examples of separations of metal ions are reported. The possibility of bypassing the single stage character of SLM separations by using multilayer composite SLMs, arranged in series, is also analyzed. Finally, the factors which control the stability of SLMs are briefly discussed. 28 references, 27 figures, 6 tables.

  13. Separation of metal species by supported liquid membranes

    SciTech Connect

    Danesi, P.R.

    1984-01-01

    The works performed on the transport and separation properties of supported liquid membranes (SLM) are reviewed. The models and equations which describe the permeation through SLMs of metal species are described. These models have been tested with various carriers absorbed on flat-sheet and hollow-fiber SLMs by measuring the permeation of several metal species of hydrometallurgical and nuclear interest. An equation for the separation factor of metal species in SLM processes and examples of separations of metal ions are reported. The possibility of bypassing the single stage character of SLM separations by using multilayer composite SLMs, arranged in series, is also analyzed. Finally, the factors which control the stability of SLMs are briefly discussed.

  14. 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.

  15. 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.

  16. Properties required by extractants and diluents for the decontamination of liquid wastes using supported liquid membranes

    SciTech Connect

    Dozol, J.F.; Rouquette, H.; Eymard, S.; Tournois, B.

    1993-12-31

    Macrocyclic extractants are now being studied more and more often for the decontamination of radioactive liquid wastes: coronands (crown ethers, azacrown...) and cryptands. As these very sophisticated compounds are expensive, the best technique is supported liquid membranes which need a very low extractant inventory. This paper deals with the properties required by the extractant and the diluent in order to be used in an SLM device and to ensure a stable and efficient SLM: solubility of the extractant in organic compounds and in aqueous solutions; size of crown ether cavities; influence of the substituent groups on the selectivity of the crown ether; and influence of the properties of the diluent (polarity, transport of acidity) on the efficiency of the process and on the stability of the membrane (interfacial tension between the organic and aqueous phases, solubility in the aqueous phase). The influence of these parameters is illustrated by experiments performed in order to remove strontium and cesium from high sodium content liquid waste. The studies described in this paper are focused on the decategorization of evaporator concentrates arising from the reprocessing of spent fuel.

  17. 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.

  18. 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.

  19. 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.

  20. Enhanced mechanical properties and blood compatibility of PDMS/liquid crystal cross-linked membrane materials.

    PubMed

    Rao, Huaxin; Zhang, Ziyong; Liu, Fanna

    2013-04-01

    A novel polydimethylsiloxane/liquid crystal cross-linked membrane (PDMS/LC) was prepared by using PDMS containing vinyl groups and LCs containing unsaturated linkages as matrix materials. Mechanical properties, liquid crystalline performance and blood compatibility of the PDMS/LC cross-linked membrane containing different LC contents and LC groups were investigated, respectively. The results showed that mechanical properties of the membrane increased more significantly than those of pure PDMS membranes. The PDMS/LC cross-linked membrane also possessed better membrane-forming ability, lower hemolysis rate, less platelets adhesion and more favorable anti-coagulant properties. Additionally, mechanical properties and blood compatibility of the membrane can be enhanced simultaneously and obviously due to the introduction of the cholesteric liquid crystals and the application of the preferred cross-linked reaction without byproducts.

  1. 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.

  2. 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)

  3. 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.

  4. Colloidal membranes: The rich confluence of geometry and liquid crystals

    NASA Astrophysics Data System (ADS)

    Kaplan, Cihan Nadir

    A simple and experimentally realizable model system of chiral symmetry breaking is liquid-crystalline monolayers of aligned, identical hard rods. In these materials, tuning the chirality at the molecular level affects the geometry at systems level, thereby inducing a myriad of morphological transitions. This thesis presents theoretical studies motivated by the rich phenomenology of these colloidal monolayers. High molecular chirality leads to assemblages of rods exhibiting macroscopic handedness. In the first part we consider one such geometry, twisted ribbons, which are minimal surfaces to a double helix. By employing a theoretical approach that combines liquid-crystalline order with the preferred shape, we focus on the phase transition from simple flat monolayers to these twisted structures. In these monolayers, regions of broken chiral symmetry nucleate at the interfaces, as in a chiral smectic A sample. The second part particularly focuses on the detailed structure and thermodynamic stability of two types of observed interfaces, the monolayer edge and domain walls in simple flat monolayers. Both the edge and "twist-walls" are quasi-one-dimensional bands of molecular twist deformations dictated by local chiral interactions and surface energy considerations. We develop a unified theory of these interfaces by utilizing the de Gennes framework accompanied by appropriate surface energy terms. The last part turns to colloidal "cookies", which form in mixtures of rods with opposite handedness. These elegant structures are essentially flat monolayers surrounded by an array of local, three dimensional cusp defects. We reveal the thermodynamic and structural characteristics of cookies. Furthermore, cookies provide us with a simple relation to determine the intrinsic curvature modulus of our model system, an important constant associated with topological properties of membranes. Our results may have impacts on a broader class of soft thin films.

  5. 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.

  6. Gelled Ionic Liquid-Based Membranes: Achieving a 10,000 GPU Permeance for Post-Combustion Carbon Capture with Gelled Ionic Liquid-Based Membranes

    SciTech Connect

    2011-02-02

    IMPACCT Project: Alongside Los Alamos National Laboratory and the Electric Power Research Institute, CU-Boulder is developing a membrane made of a gelled ionic liquid to capture CO2 from the exhaust of coal-fired power plants. The membranes are created by spraying the gelled ionic liquids in thin layers onto porous support structures using a specialized coating technique. The new membrane is highly efficient at pulling CO2 out of coal-derived flue gas exhaust while restricting the flow of other materials through it. The design involves few chemicals or moving parts and is more mechanically stable than current technologies. The team is now working to further optimize the gelled materials for CO2 separation and create a membrane layer that is less than 1 micrometer thick.

  7. Mechanical Properties of Composite SPEEK Polymer Membranes Modified with Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Sprugis, E.; Reinholds, I.; Vaivars, G.

    2015-03-01

    In this work, the mechanical properties of sulphonated polyetheretherketone (SPEEK) membranes impregnated with 3 different ionic liquids (1-butyl-2,3-dimethyl- imidazolium dimethylphosphate ([BMMIM][Me2PO4])), 1,2,3-trimethylimidazolium dimethylphosphate ([MMMIM][Me2PO4])), 1,3-dimethylimidazolium dimethylphosphate ([MMIM][Me2PO4])) have been investigated. Prepared SPEEK/ionic liquid composite membranes are characterized by mechanical testing both in room and elevated temperatures. It was found that the stiffness and tensile strength of composites decreased by increasing the content of ionic liquid and the length of alkyl radical in ionic liquid as well as by increasing the temperature.

  8. 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.

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

    PubMed Central

    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. PMID:24065073

  10. 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

    2012-01-01

    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.

  11. Modeling of the mass transfer rates of metal ions across supported liquid membranes. 1: Theory

    SciTech Connect

    Elhassadi, A.A.; Do, D.D.

    1999-01-01

    This paper deals with the modeling of the transport and separation of metal ions across supported liquid membranes. The mass transfer resistance at the liquid-membrane interfaces and the interfacial chemical reactions at both the extracting side and the stripping side are taken into account in the model equations. Simple analysis of the time scale of the system shows the influence of various important parameters and their interactions on the overall transport rate. Parametric studies are also dealt with in this paper.

  12. SEPARATION PROPERTIES OF SURFACE MODIFIED SILICA SUPPORTED LIQUID MEMBRANES FOR DIVALENT METAL REMOVAL/RECOVERY

    EPA Science Inventory

    The synthesis and separation properties of a mesoporous silica supported liquid membrane (SLM) were studied. The membranes consisted of a silica layer, from dip-coated colloidal silica, on a a-alumina support, modified with DCDMS (dichlorodimethyl silane) to add surface methyl g...

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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. PMID:27540170

  18. Polyaromatic hydrocarbons do not disturb liquid-liquid phase coexistence, but increase the fluidity of model membranes.

    PubMed

    Liland, Nina S; Simonsen, Adam C; Duelund, Lars; Torstensen, Bente E; Berntssen, Marc H G; Mouritsen, Ole G

    2014-12-01

    Polyaromatic hydrocarbons (PAHs) is a group of compounds, many of which are toxic, formed by incomplete combustion or thermal processing of organic material. They are highly lipophilic and thus present in some seed oils used for human consumption as well as being increasingly common in aquaculture diets due to inclusion of vegetable oils. Cytotoxic effects of PAHs have been thought to be partly due to a membrane perturbing effect of these compounds. A series of studies were here performed to examine the effects of three different PAHs (naphthalene, phenanthrene and benzo[a]pyrene) with different molecular sizes (two, three and five rings, respectively) and fat solubility (Kow 3.29, 4.53 and 6.04, respectively) on membrane models. The effects of PAHs on liquid-liquid phase coexistence in solid-supported lipid bilayers (dioleoylphosphocholine:dipalmitoylphosphatidylcholine:cholesterol) were assessed using fluorescence microscopy. Benzo[a]pyrene had a slight affinity for the liquid-ordered phase, but there were no effects of adding any of the other PAHs on the number or size of the liquid domains (liquid-ordered and liquid-disordered). Benzo[a]pyrene and phenanthrene, but not naphthalene, lowered the transition temperature (Tm) and the enthalpy (ΔH) characterising the transition from the solid to the liquid-crystalline phase in DPPC vesicles. The membrane effects of the PAH molecules are likely related to size, with bigger and more fat-soluble molecules having a fluidising effect when embedded in the membrane, possibly causing some of the observed toxic effects in fish exposed to these contaminants.

  19. Liquid but Durable: Molecular Dynamics Simulations Explain the Unique Properties of Archaeal-Like Membranes

    NASA Astrophysics Data System (ADS)

    Chugunov, Anton O.; Volynsky, Pavel E.; Krylov, Nikolay A.; Boldyrev, Ivan A.; Efremov, Roman G.

    2014-12-01

    Archaeal plasma membranes appear to be extremely durable and almost impermeable to water and ions, in contrast to the membranes of Bacteria and Eucaryota. Additionally, they remain liquid within a temperature range of 0-100°C. These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature. In this work, we use molecular dynamics simulations to assess at the atomistic level the structure and dynamics of a series of model archaeal membranes with lipids that have tetraether chemical nature and ``branched'' hydrophobic tails. We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells. This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

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

    PubMed

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

    2015-12-01

    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

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

    PubMed

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

    2015-12-01

    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

  2. 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

  3. 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.

  4. 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.

  5. 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

    2016-01-01

    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

  6. An application of supported liquid membranes for removal of inorganic contaminants from groundwater

    SciTech Connect

    Chiarizia, R. |; Horwitz, E.P.; Hodgson, K.M.

    1991-12-31

    This review paper summarizes the results of an investigation on teh use of supported liquid membranes for the removal of uranium (VI) and some anionic contaminants (technetium(VII), chromium(VI) and nitrates) from the Hanford site groundwater. As a membrane carrier for U(VI), bis(2,4,4-trimethylpentyl)phosphinic acid was selected because of its high selectivity over calcium and magnesium. The water soluble complexing agent 1-hydroxyethane-1,1-diphosphonic acid was used as stripping agent. For the anionic contaminants the long-chain aliphatic amines Primene JM-T (primary)., Amberlite LA-1 (secondary) and trilaurylamine (tertiary) were investigated as membrane carriers. Among these amines, Amberlite LA-2 proved to be the most effective carrier for the simultaneous removal of the investigated anion contaminants. A good long-term stability (at least one month) of the liquid membranes was obtained, especially in the uranium(VI) removal. 8 refs., 4 figs., 4 tabs.

  7. An application of supported liquid membranes for removal of inorganic contaminants from groundwater

    SciTech Connect

    Chiarizia, R. Westinghouse Hanford Co., Richland, WA ); Horwitz, E.P. ); Hodgson, K.M. )

    1991-01-01

    This review paper summarizes the results of an investigation on teh use of supported liquid membranes for the removal of uranium (VI) and some anionic contaminants (technetium(VII), chromium(VI) and nitrates) from the Hanford site groundwater. As a membrane carrier for U(VI), bis(2,4,4-trimethylpentyl)phosphinic acid was selected because of its high selectivity over calcium and magnesium. The water soluble complexing agent 1-hydroxyethane-1,1-diphosphonic acid was used as stripping agent. For the anionic contaminants the long-chain aliphatic amines Primene JM-T (primary)., Amberlite LA-1 (secondary) and trilaurylamine (tertiary) were investigated as membrane carriers. Among these amines, Amberlite LA-2 proved to be the most effective carrier for the simultaneous removal of the investigated anion contaminants. A good long-term stability (at least one month) of the liquid membranes was obtained, especially in the uranium(VI) removal. 8 refs., 4 figs., 4 tabs.

  8. 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

    2016-01-01

    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.

  9. 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

  10. Microporous membrane liquid-liquid extraction coupled on-line with normal-phase liquid chromatography for the determination of cationic surfactants in river and waste water.

    PubMed

    Norberg, J; Thordarson, E; Mathiasson, L; Jönsson, J A

    2000-02-11

    Membrane-based continuous liquid-liquid extraction combined on-line with normal-phase liquid chromatography is proposed for the determination of cationic surfactants in complex aqueous samples. The technique has the potential for complete automation. Selective enrichment of cationic surfactants from spiked river water and waste-water samples with simultaneous removal of matrix constituents, followed by a quantitative transfer of the extract onto a liquid chromatographic column and separation of the surfactant homologues yielding low detection limits, has been realised. The homologues of alkyldimethylbenzylammonium chloride (Dodigen 226) were chosen as model compounds in the method development. Dodigen homologues were ion-paired with heptanoic acid and extracted into chlorobutane by means of microporous membrane liquid-liquid extraction. It was thereby possible to attain an enrichment of over 250 times for one of the homologues, viz. the concentration in the organic liquid is 250 times higher than in the original sample. Detection limits for the three best-detected homologues of the mixture were in the range 0.7-5 microg/l in spiked river water samples. Ion-pair normal-phase liquid chromatography, again with heptanoic acid as counter-ion, gave the necessary separation of the surfactant homologues.

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

    SciTech Connect

    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.

  12. 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.

  13. 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.

  14. 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.

  15. Effect of choline carboxylate ionic liquids on biological membranes

    PubMed Central

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

    2015-01-01

    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. PMID:25444662

  16. 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.

  17. Graphene oxide membrane for liquid phase organic molecular separation

    NASA Astrophysics Data System (ADS)

    Liu, Renlong; Arabale, Girish; Kim, Jinseon; Sun, Ke; Lee, Yongwoon; Ryu, Changkook; Lee, Changgu

    2015-03-01

    The selective permeation of organic solvents and water through graphene oxide (GO) membranes has been demonstrated. Water was found to permeate through GO membranes faster than various alcohols. The permeation rates of propanol are about 80 times lower than that of water. Taking advantage of the differences in the permeation rates, we separated water from the alcohols and obtained alcohols with high purity. For ethanol and 1-propanol, binary solutions of the alcohol and water were filtered efficiently to produce alcohols with concentration of about 97%. However, the selectivity of the filtration of methanol is significantly lower than those of the other alcohols. To understand the mechanism we followed the structural changes in the GO membranes by X-Ray diffraction analysis. From the X-ray diffraction results we speculate that the selectivity of the permeation of water and alcohols is closely related to the molecular sizes of the solvents and their polarity. In order to demonstrate the potential applications of this process for the selective removal of water from aqueous organic mixtures, we performed the separation of water from a bio-oil containing 73% of water. The majority of the water was filtered out resulting in a higher purity bio-oil.

  18. Extraction of aluminum from a pickling bath with supported liquid membrane extraction

    SciTech Connect

    Berends, A.M.; Witkamp, G.J.; Rosmalen, G.M. van

    1999-04-01

    Large amounts of waste are produced yearly in the galvanic and chemical surface treatment industry. Bath liquids used in the various processes lose their function due to contamination. The spent bath liquids have to be replaced and treated prior to disposal, leading to high costs and a high environmental burden. In this paper, a proposed solution to the problem is investigated: the selective removal of the contaminant with supported liquid membrane extraction. The extraction of aluminum, a contaminant at high concentrations, from a pickling bath liquid with hydrofluoric acid and phosphoric acid as its main components has been carried out with the basic extractants Alamine 308 and Alamine 336 in a flat sheet-supported liquid membrane setup. Aluminum transport rates were obtained in the order of 10{sup {minus}6}--10{sup {minus}5} mol/(m{sup 2} {center_dot} s), which are normal values for this technique. The extraction was not completely selective as dissolved phosphorus was coextracted. In all experiments, precipitation took place on the surface of the liquid membrane and in the bulk of the strip phase. Increasing the stripping alkalinity from pH = 8 to pH = 13 reduced the amount of precipitation in the bulk of the strip phase but caused a substantial decrease in the aluminum flux. The precipitation prevents industrial application of the systems investigated.

  19. Elucidating through-plane liquid water profile in a polymer electrolyte membrane fuel cell.

    SciTech Connect

    Wang, Yun; Chen, Ken Shuang

    2010-10-01

    In this paper, a numerical model incorporating micro-porous layers (MPLs) is presented for simulating water transport within the gas diffusion layers (GDLs) and MPLs as well as across their interfaces in a polymer electrolyte membrane (PEM) fuel cell. One-dimensional analysis is conducted to investigate the impacts of MPL and GDL properties on the liquid-water profile across the anode GDL-MPL and cathode MPL-GDL regions. Furthermore, two-dimensional numerical simulations that take MPLs into account are also carried out to elucidate liquid water transport, particularly through-plane liquid-water profile in a PEM fuel cell. Results from case studies are presented.

  20. 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...

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

    SciTech Connect

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

    1992-07-01

    A number of new macrocyclic ligands was prepared for transport studies. The cryptands were prpepared (18-40% yield) by a new metal carbonate-catalyzed one-step method from 1 mole oligoethyleneoxy diamine and 2 moles diahlide derivative of oligoethylene glycol. Bis-crown ethers were also isolated in 17-30% yields. Cage compounds were also prepared; they interact with various metal ions and protons. Back extraction and dual module hollow fiber membrane separation experiments were used to study the cation selectivity of new ligands, including crown thioethers. An isothermal flow calorimeter is being constructed for studies of macrocycle-cation reactions. 3 figs, 2 tabs.

  2. 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

    2014-09-01

    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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. A supported polymeric liquid membrane process for removal of carboxylic acids from a waste stream

    SciTech Connect

    Ho, S.V.

    1999-12-31

    The removal or elimination of organic residues from aqueous waste streams represents a major need in the chemical industry. The authors have developed a new class of membrane called supported polymeric liquid membranes that are capable of removing and concentrating low molecular weight organic compounds from dilute aqueous solutions, especially those that also contain high concentrations of inorganic salts. 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. The process has shown treatment feasibility for several types of aqueous waste streams. This paper describes the laboratory development activities for treating a waste stream containing a dilute mixture of C2-C6 carboxylic acids and nitric acid.

  8. Polyelectrolyte microcapsules as ionic liquid reservoirs within ionomer membrane to confer high anhydrous proton conductivity

    NASA Astrophysics Data System (ADS)

    Zhang, Haoqin; Wu, Wenjia; Li, Yifan; Liu, Yong; Wang, Jingtao; Zhang, Bing; Liu, Jindun

    2015-04-01

    Herein, novel composite membranes are prepared by embedding methacrylic acid polyelectrolyte microcapsules (PMCs) into sulfonated poly(ether ether ketone) (SPEEK) matrix, followed by impregnating imidazole-type ionic liquids (ILs). Within the composite membrane, the lumens of PMCs act as IL reservoirs, which provide large space for IL storage and thus significantly elevate the IL uptake. The IL leaching measurement suggests that the cross-linked shells of PMCs manipulate the IL release, endowing the composite membrane with high IL retention. Moreover, the high IL retention renders the composite membrane more anhydrous hopping sites (e.g., the imidazole groups on IL and the acid-base pairs between imidazole and sulfonic acid groups), imparting a facilitated proton conduction via Grotthuss mechanism. In particular, the composite membrane containing 12% PMCs achieves a high anhydrous proton conductivity of 33.7 mS cm-1 at 150 °C. The same membrane also exhibits a surprising steady-state IL retention of 36.9% after leaching in liquid water.

  9. Double liquid membrane system for the removal of actinides and lanthanides from acidic nuclear wastes

    SciTech Connect

    Chiarizia, R.; Danesi, P.R.

    1985-01-01

    Supported liquid membranes (SLM), consisting of an organic solution of n-octyl-(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl-phosphate (TBP) in decalin are able to perform selective separation and concentration of actinide and lanthanide ions from aqueous nitrate feed solutions and synthetic nuclear wastes. In the membrane process a possible strip solution is a mixture of formic acid and hydroxylammonium formate (HAF). The effectiveness of this strip solution is reduced and eventually nullified by the simultaneous transfer through the SLM of nitric acid which accumulates in the strip solution. A possible way to overcome this drawback is to make use of a second SLM consisting of a primary amine which is able to extract only HNO/sub 3/ from the strip solution. In this work the results obtained by experimentally studying the membrane system: synthetic nuclear waste/CMPO-TBP membrane/HCOOH-HAF strip solution/primary amine membrane/NaOH solution, are reported. They show that the use of a second liquid membrane is effective in controlling the HNO/sub 3/ concentration in the strip solution, thus allowing the actinide and lanthanide ions removal from the feed solution to proceed to completion. 15 refs., 10 figs., 1 tab.

  10. Double liquid membrane system for the removal of actinides and lanthanides from acidic nuclear wastes

    SciTech Connect

    Chiarizia, R.; Danesi, P.R.

    1987-01-01

    Supported liquid membranes (SLM), consisting of an organic solution of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and tributyl-phosphate (TBP) in decalin are able to perform selective separation and concentration of actinide and lanthanide ions from aqueous nitrate feed solutions and synthetic nuclear wastes. In the membrane process a possible strip solution is a mixture of formic acid and hydroxylammonium formate (HAF). The effectiveness of this strip solution is reduced and eventually nullified by the simultaneous transfer through the SLM of HNO3 which accumulates in the strip solution. A possible way to overcome this drawback is to make use of a second SLM consisting of a primary amine which is able to extract only HNO3 from the strip solution. In this work the results obtained by experimentally studying the membrane system: synthetic nuclear waste/CMPO-TBP membrane/HCOOH-HAF strip solution/primary amine membrane/NaOH solution, are reported. They show that the use of a second liquid membrane is effective in controlling the HNO3 concentration in the strip solution, thus allowing the actinide and lanthanide ions removal from the feed solution to proceed to completion.

  11. New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site

    SciTech Connect

    Bhave, Ramesh R

    2012-01-01

    New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site R. Bhave (Oak Ridge National Laboratory. Oak Ridge, TN) and M. R. Poirier* (Savannah River National Laboratory, Aiken SC) Solid-liquid separation is the limiting step for many waste treatment processes at the Savannah River Site. SRNL researchers have identified the rotary microfilter as a technology to improve the rate of solid-liquid separation processes. SRNL is currently developing the rotary microfilter for radioactive service and plans to deploy the technology as part of the small column ion exchange process. The rotary microfilter can utilize any filter media that is available as a flat sheet. The current baseline membrane is a 0.5 micron (nominal) porous metal filter (Pall PMM050). Previous testing with tubular filters showed that filters composed of a ceramic membrane on top of a stainless steel support produce higher flux than filters composed only of porous metal. The authors are working to develop flat sheet filter media composed of a ceramic membrane and/or ceramic-metal composite on top of a porous stainless steel support that can be used with the rotary microfilter to substantially increase filter flux resulting in a more compact, energy efficient and cost-effective high level radioactive waste treatment system. Composite membranes with precisely controlled pore size distribution were fabricated on porous metal supports. High quality uniform porous metal (316SS) supports were fabricated to achieve high water permeability. Separative layers of several different materials such as ultrafine metal particles and ceramic oxides were used to fabricate composite membranes. The fabrication process involved several high temperature heat treatments followed by characterization of gas and liquid permeability measurements and membrane integrity analysis. The fabricated composite membrane samples were evaluated in a static test cell manufactured by SpinTek. The

  12. 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.

  13. Regulating surface wettability of PEO/PLLA composite electrospun nanofibrous membrane for liquid phase filtration

    NASA Astrophysics Data System (ADS)

    Poonsit, Lalada; Sunthornvarabhas, Jackapon; Akira, Ito; Lertworasirikul, Amornrat

    2014-06-01

    The PEO/PLLA composite nanofibrous membranes were prepared by electrospinning technique for liquid phase filtration application. In this experiment, PLLA homopolymer and PLLA-PEG copolymer were added into PEO solution to increase hydrophobicity of nanofibrous membrane surface. PLLA content was fixed at 30% by weight of total solid. Morphology and fiber diameter were characterized from scanning electron microscope (SEM) images. Fiber diameters of PEO/PLLA homopolymer and PEO/PLLA-PEG copolymer are 582+/-78 nm and 657+/-167 nm, respectively. Surface wettability property of PEO/PLLA composite nanofibrous membranes were measured by apparent water contact angle. The apparent water contact angle value of PEO/PLLA is 120°+/-2°, while PEO/PEG-b-PLLA is 99°+/-7°. The surface wettability of PEO/PLLA composite nanofibrous membranes can be modified by varying type of polymer.

  14. 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

    2012-11-01

    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). PMID:23084054

  15. Backside calibration potentiometry: ion activity measurements with selective supported liquid membranes by calibrating from the inner side of the membrane.

    PubMed

    Malon, Adam; Bakker, Eric; Pretsch, Ernö

    2007-01-15

    In direct potentiometry, the magnitude of the measured potentials is used to determine the composition of the sample. While this places rather formidable demands on the required reproducibility of the associated potential measurements, typically on the order of microvolts, in vitro clinical analyses of blood samples are today successfully performed with direct potentiometry using ion-selective electrodes (ISEs). Unfortunately, most other analytical situations do not permit the sensor to be recalibrated every few minutes, as in environmental monitoring or in vivo measurements, and direct potentiometry is often bound to fail as an accurate method in these circumstances. This paper introduces a novel direction for potentiometric sensing, termed backside calibration potentiometry. Chemical asymmetries across thin supported liquid ISE membranes are assessed by determining the direction of potential drift upon changing the stirring rate on either side of the membrane. Disappearance of this drift indicates the disappearance of concentration gradients across the membrane and is used to determine the sample composition if the solution composition at the backside of the membrane and the interfering ion concentration in the sample are known. For practical determinations, the concentration of either the primary or the interfering ion is varied in the reference solution until the stirring effect disappears. The procedure is demonstrated with a Ca2+-selective membrane using Ba2+ as the dominant interfering ion. Another example includes the determination of Pb2+ in environmental samples where the pH is adjusted to a known level. At pH 4.0, H+ turns out to be the dominant interfering ion. The practical applicability of the method is shown with different environmental water samples, for which the results obtained with the novel method are compared with those obtained by traditional calibration using standard additions. The limitations of the novel method in terms of accuracy and

  16. 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).

  17. 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.

  18. 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.

  19. 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.

  20. Potentiometric responses of polymeric liquid membranes based on hydrophobic chelating agents to metal ions.

    PubMed

    Itoh, Y; Ueda, Y; Hirano, A; Sugawara, M; Tohda, K; Akaiwa, H; Umezawa, Y

    2001-05-01

    The effect of hydrophobicity of acidic chelating agents as sensing materials on the potentiometric responses of polymeric liquid membranes was investigated. The chelating agents tested were 8-quinolinol (HOx), dithizone (HDz), 1-(2-pyridylazo)-2-naphthol (PAN) and their alkylated analogues, 5-octyloxymethyl-8-quinolinol (HO8Q), di(phexylphenyl)thiocarbazone (C6HDz), 7-pentadecyloxy-1-(2-pyridylazo)-2-naphthol (C15PAN) and a series of N-alkylcarbonyl-N-phenylhydroxylamines (CnPHA, n = 3, 6, 9, 12). The distribution coefficients between membrane solvent and water were determined to evaluate the hydrophobicity of the agents. The potential-pH profiles of the membranes containing hydrophobic chelating agents demonstrated the generation of potentiometric responses, while less hydrophobic agents gave no response. A possible model for the generation of membrane potential is proposed. The charge separation is attained by the permselective uptake of metal cations by the chelating agent anion at membrane/solution interface, where the high hydrophobicity of the agent enables the anionic or deprotonated form of the agents to remain at the membrane/solution interface.

  1. 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.

  2. 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. PMID:25648681

  3. Equilibrium sampling through membranes of freely dissolved chlorophenols in water samples with hollow fiber supported liquid membrane.

    PubMed

    Liu, Jing-fu; Jönsson, Jan Ake; Mayer, Philipp

    2005-08-01

    The freely dissolved concentration (C(free)) of pollutants is generally believed to be bioavailable and thus responsible for toxic effects. The C(free) of organic weak acids and bases consists of a dissociated and a nondissociated fraction. By using chlorophenols as model compounds, a negligible-depletion extraction technique, equilibrium sampling through membranes (ESTM), was developed for the measurement of the nondissociated part of the C(free). Polypropylene hollow fiber membranes (280-microm i.d., 50-microm wall thickness, 0.1-microm pore size, 15-cm length) were impregnated with undecane in the pores in the fiber wall as liquid membrane and filled with buffer solution in the lumen as acceptor. Then, the hollow fiber membranes were placed into the sample (donor) for an equilibrium extraction after sealing the two ends. The chlorophenol concentrations in the acceptor were then determined by direct injection into a HPLC system. Finally, the C(free) of the nondissociated and the dissociated species of a chlorophenol were calculated based on its measured concentration in the acceptor, its pK(a) value, and the measured pH in sample and acceptor. Theoretically calculated distribution coefficients (D = 8-970) agree well with the experimental enrichment factors (E(e(max)) = 6-1124), and the equilibration time was observed to increase with increasing distribution coefficients (hours to days). The freely dissolved concentration of five chlorophenols, with a wide range of pK(a) (4.9-9.2) and log K(ow) (2.35-5.24), were successfully determined in model solutions of humic acids and at low-ppb levels in river and leachate water. PMID:16053291

  4. 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.

  5. Application of Liquid Emulsion Membrane Technique for the Removal of As(V) from Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Binnal, Prakash; Hiremath, Poornima G.

    2012-08-01

    Liquid emulsion membrane technique was used to remove As(V) from synthetic aqueous solutions. The emulsion was composed of Aliquat 336 as an extractant, commercial kerosene as a diluent and Span 80 (Sorbiton monooleate) as an emulsifying agent. Different types of internal phases were used, namely, sodium hydroxide, sodium carbonate, ammonium bicarbonate, sodium sulphate and sodium chloride. The effect of process parameters affecting extraction efficiency, such as, initial concentration of As(V) in feed solution, pH of feed solution, concentrations of Aliquat 336 and Span 80 in membrane phase, volume ratio of stripping phase to membrane phase, concentration of internal phase, type of internal phase, volume ratio of emulsion to feed, agitation speed during extraction and time of extraction was investigated. The optimum conditions for the extraction were determined. A maximum As(V) removal rate of 97.8 was observed under optimum conditions.

  6. 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.

  7. 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®.

  8. 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.

  9. 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.

  10. Effect of complexing agent on transport of lanthanoid elements across versatic acid liquid membrane

    SciTech Connect

    Nakamura, Shigeto; Ohashi, Sinichi; Akiba, Kenichi )

    1992-06-01

    Transport of several trivalent lanthanoids (La, Nd, Sm, Eu, Tb, Tm, and Lu) was examined across a supported liquid membrane (SLM) containing Versatic 10 (VA10) in kerosene. Lanthanoids in the feed solution can be effectively transported and concentrated into the product solution. Separation factors obtained from the transport rates for lighter lanthanoids were larger than those for heavier lanthanoids, in agreement with the result on the distribution ratios in liquid-liquid extraction. The separation factors for heavier lanthanoids were enhanced by the addition of citrate to the feed solution. The transport rate was controlled by the extraction process from the feed solution to the SLM and the diffusion process of lanthanoid VA10 complexes in SLM.

  11. 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.

  12. 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.

  13. Constitutive response and mechanical properties of PFSA membranes in liquid water

    NASA Astrophysics Data System (ADS)

    Kusoglu, Ahmet; Tang, Yaliang; Lugo, Melissa; Karlsson, Anette M.; Santare, Michael H.; Cleghorn, Simon; Johnson, William B.

    The mechanical properties and swelling behavior of perfluorosulfonic acid (PFSA) membranes in liquid water have been investigated using a custom-built, temperature-controlled water bath. Interestingly, the theoretical models of Mooney-Rivlin and Ogden for rubber elasticity are shown to reproduce the major features of the experimentally obtained stress-strain relationships. In addition, stress relaxation of the membrane subjected to a fixed strain at room temperature fits time-dependent constitutive models used to describe nonlinear rubber elasticity. Thus, the experimental results suggest that even though PFSA is not an elastomer, the constitutive models developed for rubber-like behavior can be used for describing the ex situ constitutive response of PFSA membranes with high water content. This response is in contrast to the constitutive behavior of PFSA membranes swollen in water vapor (e.g. humid air and consequently lower water absorption in the membrane) where studies have suggested constitutive behavior corresponding to that of semicrystalline polymers, including distinct features such as a linear regime followed by onset of nonlinearity.

  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. A two-component polymeric optode membrane based on a multifunctional ionic liquid.

    PubMed

    Kavanagh, Andrew; Byrne, Robert; Diamond, Dermot; Radu, Aleksandar

    2011-01-21

    This work details the use of a 2-component optode membrane which is capable of generating three distinct colours in the presence of Cu(2+) and Co(2+) ions. It has been found that the ionic liquid (IL) trihexyltetradecylphosphonium dicyanamide [P(6,6,6,14)][DCA] can act as plasticizer, ligand and transducer dye when used in poly(vinyl chloride) (PVC) membranes, which significantly simplifies the optode membrane cocktail. Upon exposure to an aqueous Cu(2+) solution, a yellow colour is generated within the membrane, while exposure to an aqueous Co(2+) solution generates a blue colour. Exposure to a solution containing both ions produces a green colour. Vibrational spectroscopy has been used to investigate the molecular basis of the IL-metal ion the binding mechanism. Analytical characteristics of the membranes including the effect of interfering ions, binding constants and the limit of detection for both ions have been estimated. Finally the case of simultaneous dual-analyte recognition is presented based on two distinct absorption maxima.

  16. Targeting cholesterol in a liquid-disordered environment by theonellamides modulates cell membrane order and cell shape.

    PubMed

    Arita, Yuko; Nishimura, Shinichi; Ishitsuka, Reiko; Kishimoto, Takuma; Ikenouchi, Junichi; Ishii, Kumiko; Umeda, Masato; Matsunaga, Shigeki; Kobayashi, Toshihide; Yoshida, Minoru

    2015-05-21

    Roles of lipids in the cell membrane are poorly understood. This is partially due to the lack of methodologies, for example, tool chemicals that bind to specific membrane lipids and modulate membrane function. Theonellamides (TNMs), marine sponge-derived peptides, recognize 3β-hydroxysterols in lipid membranes and induce major morphological changes in cultured mammalian cells through as yet unknown mechanisms. Here, we show that TNMs recognize cholesterol-containing liquid-disordered domains and induce phase separation in model lipid membranes. Modulation of membrane order was also observed in living cells following treatment with TNM-A, in which cells shrank considerably in a cholesterol-, cytoskeleton-, and energy-dependent manner. These findings present a previously unrecognized mode of action of membrane-targeting natural products. Meanwhile, we demonstrated the importance of membrane order, which is maintained by cholesterol, for proper cell morphogenesis.

  17. 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

  18. Thermoresponsive drug delivery using liquid crystal-embedded cellulose nitrate membranes.

    PubMed

    Dinarvand, Rassoul; Khodaverdi, Elham; Atyabi, Fatemeh; Erfan, Mohammad

    2006-01-01

    The aim of this study was to investigate the use of thermotropic liquid crystalline (TLC) blends of 4-pentyl-4'-cyanobiphenyl (K15) and 4-heptyl-4'-cyanobiphenyl (K21) with appropriate nematic to isotropic phase temperature (Tn - i) just above body temperature as a temperature-modulated drug permeation system. Using differential scanning calorimetry (DSC) we showed that the phase transition temperature (Tn - i) of K15 and K21 were 34.2 degrees C and 41.5 degrees C respectively. However, the thermogram of K15 and K21 blends with different ratios was shown to be a single endothermic peak similar to that of pure TLCs. K15 and K21 blends did not behave as a physical blend of two thermotropic liquid crystals with different Tn - i. However, they are rather mixed together in such ways that behave like a single unit TLC. The Tn - i of these TLC mixtures was linearly proportionate to the ratio of K15:K21. Using appropriate ratio of K15:K21 TLC, a mixture with desirable phase transition temperature was obtained. A triple layer of cellulose nitrate membranes containing a 50:50 mixture of K15 and K21 was used for drug permeation studies. This composite membrane showed good pulsatile permeation of drug molecules in response to temperature changes below and above the Tn - i of the K15 and K21 blends in a reproducible and reversible manner. Paracetamol and methimazole were chosen as hydrophobic and hydrophilic drug models, respectively. Methimazole permeability through the TLC membrane was much higher (36.0 x 10(-5) cm/s) at temperatures above the phase transition temperature of liquid crystal blends than that (7.2 x 10(-5) cm/s) at temperatures below the phase transition temperature of liquid crystal blends (38.1 degrees C).

  19. 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

  20. 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. PMID:27046045

  1. 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.

  2. 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. PMID:15776808

  3. 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.

  4. 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. PMID:24350486

  5. Membrane separation in green chemical processing: solvent nanofiltration in liquid phase organic synthesis reactions.

    PubMed

    Livingston, Andrew; Peeva, Ludmila; Han, Shejiao; Nair, Dinesh; Luthra, Satinder Singh; White, Lloyd S; Freitas Dos Santos, Luisa M

    2003-03-01

    This paper describes ideas together with preliminary experimental results for applying solvent nanofiltration to liquid phase organic synthesis reactions. Membranes for organic solvent nanofiltration have only recently (during the 1990s) become available and, to date, have been applied primarily to food processing (vegetable oil processing, in particular) and refinery processes. Applications to organic synthesis, even at a laboratory feasibility level, are few. However, these membranes have great potential to improve the environmental performance of many liquid phase synthesis reactions by reducing the need for complex solvent handling operations. Examples that are shown to be feasible are solvent exchanges, where it is desired to swap a high molecular weight molecule from one solvent to another between separate stages in a complex synthesis, and recycle and reuse of homogeneous catalysts. In solvent exchanges, nanofiltration is shown to provide a fast and effective means of swapping from a high boiling point solvent to a solvent with a lower boiling point-this is a difficult operation by means of distillation. Solvent nanofiltration is shown to be able to separate two distinct types of homogeneous catalysts, phase transfer catalysts and organometallic catalysts, from their respective reaction products. In both cases the application of organic solvent nanofiltration allows several reuses of the same catalyst. Catalyst stability is shown to be an essential requirement for this technique to be effective. Finally, we present a discussion of scale-up aspects including membrane flux and process economics.

  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. Parallel artificial liquid membrane extraction as an efficient tool for removal of phospholipids from human plasma.

    PubMed

    Ask, Kristine Skoglund; Bardakci, Turgay; Parmer, Marthe Petrine; Halvorsen, Trine Grønhaug; Øiestad, Elisabeth Leere; Pedersen-Bjergaard, Stig; Gjelstad, Astrid

    2016-09-10

    Generic Parallel Artificial Liquid Membrane Extraction (PALME) methods for non-polar basic and non-polar acidic drugs from human plasma were investigated with respect to phospholipid removal. In both cases, extractions in 96-well format were performed from plasma (125μL), through 4μL organic solvent used as supported liquid membranes (SLMs), and into 50μL aqueous acceptor solutions. The acceptor solutions were subsequently analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using in-source fragmentation and monitoring the m/z 184→184 transition for investigation of phosphatidylcholines (PC), sphingomyelins (SM), and lysophosphatidylcholines (Lyso-PC). In both generic methods, no phospholipids were detected in the acceptor solutions. Thus, PALME appeared to be highly efficient for phospholipid removal. To further support this, qualitative (post-column infusion) and quantitative matrix effects were investigated with fluoxetine, fluvoxamine, and quetiapine as model analytes. No signs of matrix effects were observed. Finally, PALME was evaluated for the aforementioned drug substances, and data were in accordance with European Medicines Agency (EMA) guidelines. PMID:27433988

  8. Liquid Water Transport in the Reactant Channels of Proton Exchange Membrane Fuel Cells

    NASA Astrophysics Data System (ADS)

    Banerjee, Rupak

    Water management has been identified as a critical issue in the development of PEM fuel cells for automotive applications. Water is present inside the PEM fuel cell in three phases, i.e. liquid phase, vapor phase and mist phase. Liquid water in the reactant channels causes flooding of the cell and blocks the transport of reactants to the reaction sites at the catalyst layer. Understanding the behavior of liquid water in the reactant channels would allow us to devise improved strategies for removing liquid water from the reactant channels. In situ fuel cell tests have been performed to identify and diagnose operating conditions which result in the flooding of the fuel cell. A relationship has been identified between the liquid water present in the reactant channels and the cell performance. A novel diagnostic technique has been established which utilizes the pressure drop multiplier in the reactant channels to predict the flooding of the cell or the drying-out of the membrane. An ex-situ study has been undertaken to quantify the liquid water present in the reactant channels. A new parameter, the Area Coverage Ratio (ACR), has been defined to identify the interfacial area of the reactant channel which is blocked for reactant transport by the presence of liquid water. A parametric study has been conducted to study the effect of changing temperature and the inlet relative humidity on the ACR. The ACR decreases with increase in current density as the gas flow rates increase, removing water more efficiently. With increase in temperature, the ACR decreases rapidly, such that by 60°C, there is no significant ACR to be reported. Inlet relative humidity of the gases does change the saturation of the gases in the channel, but did not show any significant effect on the ACR. Automotive powertrains, which is the target for this work, are continuously faced with transient changes. Water management under transient operating conditions is significantly more challenging and has not

  9. 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.

  10. Transport of chromium(VI) through a supported liquid membrane containing tri-n-octylphosphine oxide

    SciTech Connect

    Huang, T.C.; Huang, C.C.; Chen, D.H.

    1998-09-01

    In this study the transport of chromium(VI) from aqueous solutions of pH 2--4 through a supported liquid membrane (SLM) with tri-n-octylphosphine oxide (TOPO) dissolved in kerosene as a mobile carrier was investigated. The transport flux of Cr(VI) increased with an increase in the concentrations of Cr(VI) in the feed phase and of TOPO in the membrane phase, but with a decrease in pH of the feed phase. Considering the equilibria of various Cr(VI) species in the aqueous phase and of the Cr(VI)-TOPO complexes formed in the membrane phase, a permeation model including the aqueous film diffusion of HCrO{sub 4}{sup {minus}} and Cr{sub 2}O{sub 7}{sup 2{minus}} toward the membrane, the interfacial chemical reaction between them and TOPO, and the membrane diffusion of the Cr(VI)-TOPO complexes ({ovr H{sub 2}CrO{sub 4}{center_dot}(TOPO)} and {ovr H{sub 2}Cr{sub 2}O{sub 7}{center_dot}(TOPO){sub 3}}) was proposed to describe the transport of Cr(VI) through the SLM. By best fitting the transport flux equations of Cr(VI) with the experimental data using the Rosenbrock method, the apparent mass-transfer coefficients of HCrO{sub 4}{sup {minus}} and Cr{sub 2}O{sub 7}{sup 2{minus}} across the aqueous film, and those of {ovr H{sub 2}CrO{sub 4}{center_dot}(TOPO)} and {ovr H{sub 2}Cr{sub 2}O{sub 7}{center_dot}(TOPO){sub 3}} across the membrane phase, were obtained. This work helps to clarify the transport mechanism of Cr(VI) through an SLM.

  11. 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.

  12. Liquid Crystalline Block Copolymers with Brush Type Architecture: Toward Functional Membranes by Magnetic Field Alignment

    NASA Astrophysics Data System (ADS)

    Choo, Youngwoo; Gopinadhan, Manesh; Mahajan, Lalit; Kasi, Rajeswari; Osuji, Chinedum

    2015-03-01

    We introduce a novel liquid crystalline block copolymer with brush type architecture for membrane applications by magnetic field directed self-assembly. Ring-opening metathesis of n-alkyloxy cyanobiphenyl and polylactide (PLA) functionalized norbornene monomers provides efficient polymerization yielding low polydispersity block copolymers. The molecular weight of the PLA side chains, spacer length of the cyanobiphenyl mesogens are systematically varied to form well-ordered BCP morphologies at varying volume fractions. Interestingly, the system features morphology dependent anchoring condition where mesogens adopt planar anchoring on cylindrical interface while homeotropic anchoring was preferred on a planar block interface. The minority PLA domains from highly aligned materials can be readily degraded by hydrolysis to produce vertically aligned nanoporous polymer films which exhibit reversible thermal switching behavior. The polymers introduced here provide a versatile platform for scalable fabrication of aligned membranes and further functional materials based on such templates. This work was supported by NSF(CCMI-1246804).

  13. 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.

  14. Transport of cadmium(II) ion through a supported liquid membrane containing a bathocuproine

    SciTech Connect

    Saito, Takashi )

    1991-12-01

    The active transport of cadmium ions across a supported liquid membrane (SLM) containing a ligand based on a driving force supplied by the concentration gradient of the chloride ion is described. The SLM used is a microporous polypropylene membrane impregnated with a bathocuproine (4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline) solution in dibenzyl ether as a carrier. The characteristics of the cadmium ion transport system are examined under various experimental conditions. The active transport of cadmium ions through an SLM is dependent on the concentrations of the cadmium ion, ligand, and chloride ion. An equation for the permeation velocity of cadmium ions, consisting of three important factors for this transport system, is proposed.

  15. 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.

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

    PubMed

    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. PMID:25554341

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

    PubMed

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

    2014-10-28

    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.

  18. Supported liquid membranes in radioactive waste treatment processes: Recent experience and perspective

    SciTech Connect

    Nechaev, A.F.; Projaev, V.V.; Kapranchik, V.P.

    1995-12-31

    Recent experience in practical application of Supported Liquid Membranes (SLM or SUPLIM) both in the hydrometallurgy and nuclear technology has been analyzed. The results obtained allow one to consider SUPLIM as a promising technology for radioactive waste treatment. This statement is based on the evaluation of integrated socioeconomic effects, including quantity of additional chemicals, the volume of secondary technological streams and secondary wastes, simplicity and the low costs of equipment used, potential possibility to organize in situ process, and the level of the harmful impact on personnel. 35 refs.

  19. Stability Limit of Water by Metastable Vapor-Liquid Equilibrium with Nanoporous Silicon Membranes.

    PubMed

    Chen, I-Tzu; Sessoms, David A; Sherman, Zachary; Choi, Eugene; Vincent, Olivier; Stroock, Abraham D

    2016-06-16

    Liquid can sustain mechanical tension as its pressure drops below the vapor-liquid coexistence line and becomes less than zero, until it reaches the stability limit-the pressure at which cavitation inevitably occurs. For liquid water, its stability limit is still a subject of debate: the results obtained by researchers using a variety of techniques show discrepancies between the values of the stability limit and its temperature dependence as temperature approaches 0 °C. In this work, we present a study of the stability limit of water by the metastable vapor-liquid equilibrium (MVLE) method with nanoporous silicon membranes. We also report on an experimental system which enables tests of the temperature dependence of the stability limit with MVLE. The stability limit we found increases monotonically (larger tension) as temperature approaches 0 °C; this trend contradicts the centrifugal result of Briggs but agrees with the experiments by acoustic cavitation. This result confirms that a quasi-static method can reach stability values similar to that from the dynamic stretching technique, even close to 0 °C. Nevertheless, our results fall in the range of ∼ -20 to -30 MPa, a range that is consistent with the majority of experiments but is far less negative than the limit obtained in experiments involving quartz inclusions and that predicted for homogeneous nucleation. PMID:27223603

  20. Stability Limit of Water by Metastable Vapor-Liquid Equilibrium with Nanoporous Silicon Membranes.

    PubMed

    Chen, I-Tzu; Sessoms, David A; Sherman, Zachary; Choi, Eugene; Vincent, Olivier; Stroock, Abraham D

    2016-06-16

    Liquid can sustain mechanical tension as its pressure drops below the vapor-liquid coexistence line and becomes less than zero, until it reaches the stability limit-the pressure at which cavitation inevitably occurs. For liquid water, its stability limit is still a subject of debate: the results obtained by researchers using a variety of techniques show discrepancies between the values of the stability limit and its temperature dependence as temperature approaches 0 °C. In this work, we present a study of the stability limit of water by the metastable vapor-liquid equilibrium (MVLE) method with nanoporous silicon membranes. We also report on an experimental system which enables tests of the temperature dependence of the stability limit with MVLE. The stability limit we found increases monotonically (larger tension) as temperature approaches 0 °C; this trend contradicts the centrifugal result of Briggs but agrees with the experiments by acoustic cavitation. This result confirms that a quasi-static method can reach stability values similar to that from the dynamic stretching technique, even close to 0 °C. Nevertheless, our results fall in the range of ∼ -20 to -30 MPa, a range that is consistent with the majority of experiments but is far less negative than the limit obtained in experiments involving quartz inclusions and that predicted for homogeneous nucleation.

  1. Comparison of copper speciation in estuarine water measured using analytical voltammetry and supported liquid membrane techniques.

    PubMed

    Ndungu, Kuria; Hurst, Matthew P; Bruland, Kenneth W

    2005-05-01

    The supported liquid membrane (SLM) is a promising separation and preconcentration technique that is well-suited for trace metal speciation in natural waters. The technique is based on the selective complexation of metal ions by a hydrophobic ligand (carrier) dissolved in a water-immiscible organic solvent immobilized in a porous, inert membrane. This membrane separates two aqueous solutions: the test (or donor) solution and the strip (or acceptor) solution. The metal carrier complex is transported by diffusion across the membrane from the source to the strip solution where metal ions are back-extracted. The technique offers great potential to tune the selectivity by incorporating different complexing ligands in the membrane. A SLM was used to analyze the dissolved (<0.45 microm) copper speciation from two sites in the San Francisco Bay estuary; Dumbarton Bridge, [Cu]total approximately 27 nM, and San Bruno Shoals, [Cu]total approximately 23 nM. The sites were also characterized independently by differential pulse anodic stripping voltammetry (DPASV) using a Nafion-coated thin mercury film electrode (NCTMFE). The SLM employed 10 mM lasalocid, a naturally occurring carboxylic polyether ionophore, in nitrophenyl octyl ether (NPOE) asthe membrane complexing ligand, supported by a microporous, polypropylene, hydrophobic membrane. This is the first study where SLM technique has been compared with an independent speciation technique in marine waters. Results of copper speciation measurements from Dumbarton Bridge, a site in South San Francisco Bay where copper speciation has been well-characterized in previous studies using various voltammetric techniques, indicated that only about 3% (0.9 nM) of the total dissolved copper was SLM labile. The corresponding DPASV labile copper fraction was <0.4% (<0.1 nM) of total dissolved copper. The concentration of total copper binding ligands measured by the membrane technique was 471 nM as compared to 354 nM measured by DPASV, more

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

    PubMed Central

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

    2011-01-01

    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. PMID:24957613

  3. 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)

  4. Extraction of Co(II) from aqueous solution using emulsion liquid membrane.

    PubMed

    Gasser, M S; El-Hefny, N E; Daoud, J A

    2008-03-01

    The extraction equilibrium of Co(II) from thiocyanate medium by CYANEX 923 (mixture of straight chain alkylated phosphine oxides) in cyclohexane was studied. The stoichiometry of the extraction reaction was postulated based on slope analysis method and the extraction constant Kex was calculated. The stripping percentage of Co(II) with sulphuric acid from the loaded CYANEX 923 was found to increase with the increase in acid concentration. The extraction of Co(II) from aqueous thiocyanate medium into emulsion liquid membrane using CYANEX 923 extractant was also studied. The influence of different parameters such as stirring speed, surfactant concentration, pH of the extractant phase, carrier concentration, internal phase stripping acid concentration, initial Co(II) concentration as well as temperature on the emulsion stability were investigated. The applicability of the emulsion liquid membrane (ELM) process using CYANEX 923 as extractant and SPAN 80 as surfactant for the removal and the concentration of Co(II) from thiocyanate solution was investigated. The results show that it is possible to recover 95% of cobalt in the inner phase after 10 min of contacting time with a concentration factor of 5.

  5. 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.

  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. 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. PMID:27455716

  8. Mercuracarborand "anti-crown ether"-based chloride-sensitive liquid/polymeric membrane electrodes.

    PubMed

    Badr, I H; Diaz, M; Hawthorne, M F; Bachas, L G

    1999-04-01

    Highly sensitive and selective chloride liquid/polymeric membrane electrodes are described that employ [9]-mercuracarborand-3 (MC3), a neutral preorganized macrocyclic Lewis acid, as the anion carrier. MC3-based chloride-sensitive membrane electrodes, doped with different mole percentages of cationic additives (5, 10, and 60 mol % tridodecylmethylammonium chloride) relative to the amount of the carrier, exhibit enhanced potentiometric selectivity for chloride over other anions, including more lipophilic anions such as perchlorate, nitrate, and thiocyanate. In addition, the selectivity coefficients obtained are shown to meet the requirement for clinical applications. The obtained selectivity pattern is shown to correlate very well with 199Hg NMR titrations of MC3 with various anions, performed in organic solvents. Optimized membrane electrodes show a near-Nernstian response toward chloride over a wide concentration range and have micromolar detection limits. MC3-based chloride sensors show a fast response time (in the order of few seconds), as well as short recovery time. The developed mercuracarborand-based sensors do not practically respond to pH changes over the pH range of 2.5-7.0. Response characteristics (e.g., detection limit, linear range, response slope, and selectivity) of the [9]mercuracarborand-3 based chloride sensors remain essentially the same over a period of approximately 2 months, reflecting remarkable stability and well-defined chemistry of the macrocyclic Lewis acid ionophore.

  9. 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.

  10. 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.

  11. The effect of porous support composition and operating parameters on the performance of supported liquid membranes

    SciTech Connect

    Takigawa, D.Y. )

    1992-03-01

    Supported liquid membranes (SLMs) of varying porous support compositions and structures were studied for the transport of metal ions. A microporous polybenzimidazole support was synthesized and prepared in the form of an SLM. This SLM, containing the selective extractant di-(2-ethylhexyl) phosphoric acid, was evaluated for the transport of copper and neodymium. Metal ion transport reaches near completion in less than 3 h, whereas Celgard-polypropylene and Nucleopore-polycarbonate reaches only 50% completion even after 15 h. The transport driving force for acidic extractants is a pH gradient between the feed and strip solutions. Polybenzimidazole, an acid-and radiation-resistant polymer, has two protonatable tertiary nitrogens per repeat unit that may help sustain the pH driving force. Another factor may be the ability of the polybenzimidazole to hydrogen bond with the extractant. Transport through the flat-sheet SLMs was tested by using a unique cell design. Countercurrent flow of the feed and strip solutions was established through machined channels in half-cell face plates that are in a spiral, mirror-image pattern with respect to each other, with the flat-sheet SLM interposed between the two channeled solutions. Advantages comprised in the design of the two clamped half-cells (tangential entry, zero primary pressure, zero pressure differential, controlled flow regimes, no sharp turns, and channeled flow) give operating parameters that will not physically dislodge the liquid membrane from the porous support; consequently, the lifetime of the support is increased. Permeability coefficients remained unchanged after a month of daily use versus 20 to 100% declines for membranes in other cell configurations.

  12. 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. PMID:24528277

  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. 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.

  16. 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.

  17. Impact of membrane solid-liquid separation on design of biological nutrient removal activated sludge systems.

    PubMed

    Ramphao, M; Wentzel, M C; Merritt, R; Ekama, G A; Young, T; Buckley, C A

    2005-03-20

    Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only in the design of the BNR system itself, but also in the design approach for the whole wastewater treatment plant (WWTP). In multizone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic, and aerobic zones (i.e., fixed volume fractions), the mass fractions can be controlled (within a range) with the interreactor recycle ratios. This zone mass fraction flexibility is a significant advantage in membrane BNR systems over conventional BNR systems with SSTs, because it allows for changing of the mass fractions to optimize biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios in the upper range (f(q) approximately 2.0), aerobic mass fractions in the lower range (f(maer) < 0.60), and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs. Although the volume reduction compared with equivalent conventional BNR systems with secondary settling tanks is not as large (40% to 60%), the cost of the membranes can be offset against sludge thickening and stabilization costs. Moving from a flow-unbalanced raw wastewater system to a flow-balanced (f(q) = 1), low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes from extended aeration to include primary sludge stabilization. The cost of primary sludge treatment then has to be paid from the savings from the increased WWTP capacity.

  18. A comparison of BNR activated sludge systems with membrane and settling tank solid-liquid separation.

    PubMed

    Ramphao, M C; Wentzel, M C; Ekama, G A; Alexander, W V

    2006-01-01

    Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only to the design of the membrane bio-reactor (MBR) BNR system itself, but also to the design approach for the whole wastewater treatment plant (WWTP). In multi-zone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic and aerobic zones (i.e. fixed volume fractions), the mass fractions can be controlled (within a range) with the inter-reactor recycle ratios. This zone mass fraction flexibility is a significant advantage of MBR BNR systems over BNR systems with secondary settling tanks (SSTs), because it allows changing the mass fractions to optimise biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios (fq) in the upper range (fq approximately 2.0), aerobic mass fractions in the lower range (f(maer) < 0.60) and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs (no primary settling and long sludge age). However, the volume reduction compared with equivalent BNR systems with SSTs will not be large (40-60%), but the cost of the membranes can be offset against sludge thickening and stabilisation costs. Moving from a flow unbalanced raw wastewater system to a flow balanced (fq = 1) low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes away from extended aeration to include primary sludge stabilisation. The cost of primary sludge treatment then has to be offset against the savings of the increased WWTP capacity.

  19. A comparison of BNR activated sludge systems with membrane and settling tank solid-liquid separation.

    PubMed

    Ramphao, M C; Wentzel, M C; Ekama, G A; Alexander, W V

    2006-01-01

    Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only to the design of the membrane bio-reactor (MBR) BNR system itself, but also to the design approach for the whole wastewater treatment plant (WWTP). In multi-zone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic and aerobic zones (i.e. fixed volume fractions), the mass fractions can be controlled (within a range) with the inter-reactor recycle ratios. This zone mass fraction flexibility is a significant advantage of MBR BNR systems over BNR systems with secondary settling tanks (SSTs), because it allows changing the mass fractions to optimise biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios (fq) in the upper range (fq approximately 2.0), aerobic mass fractions in the lower range (f(maer) < 0.60) and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs (no primary settling and long sludge age). However, the volume reduction compared with equivalent BNR systems with SSTs will not be large (40-60%), but the cost of the membranes can be offset against sludge thickening and stabilisation costs. Moving from a flow unbalanced raw wastewater system to a flow balanced (fq = 1) low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes away from extended aeration to include primary sludge stabilisation. The cost of primary sludge treatment then has to be offset against the savings of the increased WWTP capacity. PMID:16889266

  20. Impact of membrane solid-liquid separation on design of biological nutrient removal activated sludge systems.

    PubMed

    Ramphao, M; Wentzel, M C; Merritt, R; Ekama, G A; Young, T; Buckley, C A

    2005-03-20

    Installing membranes for solid-liquid separation into biological nutrient removal (BNR) activated sludge (AS) systems makes a profound difference not only in the design of the BNR system itself, but also in the design approach for the whole wastewater treatment plant (WWTP). In multizone BNR systems with membranes in the aerobic reactor and fixed volumes for the anaerobic, anoxic, and aerobic zones (i.e., fixed volume fractions), the mass fractions can be controlled (within a range) with the interreactor recycle ratios. This zone mass fraction flexibility is a significant advantage in membrane BNR systems over conventional BNR systems with SSTs, because it allows for changing of the mass fractions to optimize biological N and P removal in conformity with influent wastewater characteristics and the effluent N and P concentrations required. For PWWF/ADWF ratios in the upper range (f(q) approximately 2.0), aerobic mass fractions in the lower range (f(maer) < 0.60), and high (usually raw) wastewater strengths, the indicated mode of operation of MBR BNR systems is as extended aeration WWTPs. Although the volume reduction compared with equivalent conventional BNR systems with secondary settling tanks is not as large (40% to 60%), the cost of the membranes can be offset against sludge thickening and stabilization costs. Moving from a flow-unbalanced raw wastewater system to a flow-balanced (f(q) = 1), low (usually settled) wastewater strength system can double the ADWF capacity of the biological reactor, but the design approach of the WWTP changes from extended aeration to include primary sludge stabilization. The cost of primary sludge treatment then has to be paid from the savings from the increased WWTP capacity. PMID:15696540

  1. Permeation rate of metal species through supported liquid membranes: diffusional and chemical resistances with cationic and anionic carriers

    SciTech Connect

    Danesi, P.R.; Horwitz, E.P.; Rickert, P.G.

    1983-01-01

    Facilitated transport by means of a mobile carrier in an organic diluent and adsorbed on a polymeric film, through supported liquid membranes (SLM), is a new method for the separation and recovery of metal ions. A permeability coefficient equation for this transport was tested. The facilitated transport of Cu/sup 2 +/ and Fe/sup 3 +/ ions through a SLM was characterized with respect to the membrane resistance. Transport of Am/sup 3 +/ through a SLM was also characterized. (DLC)

  2. Modeling of the mass transfer rates of metal ions across supported liquid membranes. 2: Comparison between theory and experiment

    SciTech Connect

    Elhassadi, A.A.; Do, D.D.

    1999-02-01

    The model equations developed in Part 1 were tested using experimental data reported in the literature and produced in this work. It was found that uranium(VI) and thorium(IV) can be selectively separated and concentrated using supported liquid membranes. Depending on the way the liquid membranes are designed, the selectivity toward a specific metal can be predetermined. The effect of the ratio of the effective diffusivity to bulk diffusivity in free solution was found to behave with the same characteristic of systems of preferentially adsorbed solutes.

  3. 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

  4. 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.

  5. 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.

  6. 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. PMID:27264787

  7. Drag Coefficient of a Liquid Domain in a Fluid Membrane Surrounded by Confined Three-Dimensional Fluids

    NASA Astrophysics Data System (ADS)

    Fujitani, Youhei

    2013-08-01

    It is thought that, in a biomembrane, some minor lipid constituents are concentrated in a domain called the lipid raft. Some raftlike domains in a lipid-bilayer membrane can be regarded as two-dimensional droplets. The membrane viscosities inside and outside the domain are generally different. The present author previously studied the drag coefficient of a circular liquid domain in a flat fluid membrane surrounded by three-dimensional fluids, which occupy the semi-infinite spaces on both sides of the membrane. Here we generalize this problem by assuming that the surrounding fluids are confined by container walls parallel to the membrane. Errors in the present author's previous studies are also corrected in this paper.

  8. Threshold for spontaneous oscillation in a three-phase liquid membrane system involving nonionic surfactant.

    PubMed

    Nanzai, Ben; Funazaki, Tomohisa; Igawa, Manabu

    2010-09-16

    This study of self-oscillation was conducted using a new three-phase liquid membrane system of ethanol aqueous solution, benzyl alcohol solution with nonionic surfactant, and pure water. Relations of the initial ethanol concentration to the oscillation amplitude and frequency, and to the induction period before oscillations were investigated. The oscillation amplitude is independent of the initial ethanol concentration, but the frequency and the induction period are related to it. The oscillation frequency increased concomitantly with the increased ethanol initial concentration, but the induction period before the electrical oscillations decreased with increasing concentration. To estimate the influence of ethanol diffusion on the electrical oscillations, the ethanol concentration in each phase was measured using separate experiments after different durations of oscillation. The diffusion coefficient was calculated using Fick's second law. Results show successful estimation of the threshold for oscillations. The threshold is defined in terms of the ethanol concentration at the interface between the benzyl alcohol phase and the pure water phase.

  9. Transport of europium through supported liquid membrane containing dihexyl-N,N-diethyl-carbamoyl-methyl-phosphonate

    SciTech Connect

    Nakamura, Shigeto; Akiba, Kenichi )

    1989-12-01

    The transport of europium has been studied through a supported liquid membrane (SLM) impregnated with dihexyl-N,N-diethyl-carbamoyl-methyl-phosphonate (CMP). Europium was effectively extracted from the perchlorate solution into SLM, but was insufficiently stripped to a dilute acid solution. The addition of 1-decanol improved the stripping process, and quantitative transport of europium was achieved. By the combination of two SLM systems consisting of diisodecylphosphoric acid and CMP, europium was transported from the feed solution (0.1 M HNO{sub 3}) through the intermediate solution (1 M HClO{sub 4} + 4 M NaClO{sub 4}) to the product solution (0.1 M HNO{sub 3}) and effectively concentrated by a factor of about 20.

  10. Transport of silver(I) ion through a supported liquid membrane using bathocuproine as a carrier

    SciTech Connect

    Saito, Takashi

    1998-04-01

    The active transport of silver ions through a supported liquid membrane (SLM) containing bathocuproine (4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline) as a carrier was investigated under various experimental conditions. The magnitude of the permeation velocity of metallic ions through the SLM was in the order Ag{sup +} > Cd{sup 2+} {much_gt} Zn{sup 2+} > Cu{sup 2+} when nitrite ion was used as the pairing ion species that is cotransported with metallic ion. The permeation velocity of silver(I) ions through an SLM was dependent on the concentrations of the silver ion, bathocuproine, and nitrite ion. An equation for the transport of silver ions, consisting of three important factors, i.e., the concentrations of metallic ion, carrier, and pairing ion species, was derived.

  11. Dielectric spectroscopy of aerosil-dispersed liquid crystal embedded in Anopore membranes.

    PubMed

    Sinha, G; Leys, J; Glorieux, C; Thoen, J

    2005-11-01

    The complex dielectric permittivity epsilon* values are presented for aerosil-dispersed 4-pentyl-4-cyanobiphenyl (5CB) confined in Anopore membranes. The dielectric permittivities are measured in the frequency range from 10(-2) Hz to 1 GHz at temperatures ranging from 50 degrees C down to -20 degrees C. In bulk 5CB, which has only a nematic phase, there exist two main relaxation processes: one due to the rotation of molecules around their short axes for parallel orientation of the director to the probing field and another fast relaxation process due to the librational motion of molecules for perpendicular orientation. Inside Anopore membranes both these main relaxation processes can be observed, but with subtle differences. The relaxation process due to the rotation of molecules around the short axis is faster in Anopores at all temperatures in comparison with the bulk process. Hydrophilic aerosil particles, when dispersed in the liquid-crystal (LC) phase, attach to each other via hydrogen bonds and form a three-dimensional interconnecting aerosil network, thus dividing the LC phase into small domains. Dispersing 5CB with different concentrations of hydrophilic aerosils leads to a decrease in relaxation time with aerosil concentration. In these dispersed systems a slow additional relaxation process emerges. This slow process becomes stronger with higher concentrations of aerosil. From our experiments we conclude that this process is the relaxation of 5CB molecules homeotropically aligned to the surface of the aerosil particles. In the case of 5CB-aerosil dispersions enclosed in Anopore membranes this slow process still exists and increases also with aerosil concentration. The relaxation time of the rotation of the 5CB molecules around their short axis systematically increases in these 5CB-aerosil samples in Anopore membranes with aerosil concentration from the 5CB-Anopore behavior towards the behavior observed for 5CB-aerosil dispersions. We explain the evolution

  12. 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.

  13. The effect of porous support composition and operating parameters on the performance of supported liquid membranes

    SciTech Connect

    Takigawa, D.Y.

    1991-02-01

    Factors, such as porous support composition and operating parameters, that influence the performance of supported liquid membranes (SLMs) were investigated. SLMs of varying porous support compositions and structures were studied for the transport of metal ions. A microporous polybenzimidazole support was synthesized and prepared in the form of an SLM. This SLM containing the selective extractant di-(2-ethylhexyl)phosphoric acid was evaluated for the transport of copper and neodymium. Dramatically improved performance over that of commercially available membranes was found in tests for removing the metal ions from solution. Metal ion transport reaches near completion in less than 3 hours, whereas Celgard-polypropylene and Nuclepore-polycarbonate reaches only 50% completion even after 15 hours. The transport driving force for acidic extractants is a pH gradient between the feed and strip solutions. Polybenzimidazole, an acid- and radiation-resistant polymer, has two protonatable tertiary nitrogens per repeat unit that may help sustain the pH driving force. Another factor may be the ability of the polybenzimidazole to hydrogen bond with the extractant. Transport through the flat-sheet SLMs were tested using a unique cell design. Countercurrent flow of the feed and strip solutions was established through machined channels in half-cell faceplates that are in a spiral, mirror-image pattern with respect to each other, with the flat-sheet SLM interposed between the two channeled solutions. 7 refs., 14 figs.

  14. Electroactive nanostructured polymer actuators fabricated using sulfonated styrenic pentablock copolymer/montmorillonite/ionic liquid nanocomposite membranes

    NASA Astrophysics Data System (ADS)

    Lee, Jang-Woo; Hong, Soon Man; Koo, Chong Min

    2014-08-01

    High-bendable, air-operable ionic polymer-metal composite (IPMC) actuators composed of electroactive nanostructured middle-block sulfonated styrenic pentablock copolymer (SSPB)/sulfonated montmorillonite (s-MMT) nanocomposite electrolyte membranes with bulky imidazolium ionic liquids (ILs) incorporated were fabricated and their bending actuation performances were evaluated. The SSPB-based IPMC actuators showed larger air-operable bending displacements, higher displacement rates, and higher energy efficiency of actuations without conventional IPMC bottlenecks, including back relaxation and actuation instability during actuation in air, than the Nafion counterpart. Incorporation of s-MMT into the SSPB matrix further enhanced the actuation performance of the IPMC actuators in terms of displacement, displacement rate, and energy efficiency. The remarkably high performance of the SSPB/s-MMT/IL IPMCs was considered to be due to the microphase-separated large ionic domains of the SSPB (the average diameter of the ionic domain: ca. 20 nm) and the role of s-MMT as an ionic bridge between the ionic domains, and the ion pumping effect of the bulky imidazolium cations of the ILs as well. The microphase-separated nanostructure of the composite membranes caused a high dimensional stability upon swelling in the presence of ILs, which effectively preserved the original electrode resistance against swelling, leading to a high actuation performance of IPMC.

  15. A New Emulsion Liquid Membrane Based on a Palm Oil for the Extraction of Heavy Metals

    PubMed Central

    Björkegren, Sanna; Fassihi Karimi, Rose; Martinelli, Anna; Jayakumar, Natesan Subramanian; Hashim, Mohd Ali

    2015-01-01

    The extraction efficiency of hexavalent chromium, Cr(VI), from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM) technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC), to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water) does not significantly influence the extraction rate. PMID:25915191

  16. 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.

  17. 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. PMID:27332833

  18. A new emulsion liquid membrane based on a palm oil for the extraction of heavy metals.

    PubMed

    Björkegren, Sanna; Karimi, Rose Fassihi; Martinelli, Anna; Jayakumar, Natesan Subramanian; Hashim, Mohd Ali

    2015-01-01

    The extraction efficiency of hexavalent chromium, Cr(VI), from water has been investigated using a vegetable oil based emulsion liquid membrane (ELM) technique. The main purpose of this study was to create a novel ELM formulation by choosing a more environmentally friendly and non-toxic diluent such as palm oil. The membrane phase so formulated includes the mobile carrier tri-n-octylmethylammonium chloride (TOMAC), to facilitate the metal transport, and the hydrophilic surfactant Tween 80 to facilitate the dispersion of the ELM phase in the aqueous solution. Span 80 is used as surfactant and butanol as co-surfactant. Our results demonstrate that this novel ELM formulation, using the vegetable palm oil as diluent, is useful for the removal of hexavalent chromium with an efficiency of over 99% and is thus competitive with the already existing, yet less environmentally friendly, ELM formulations. This result was achieved with an optimal concentration of 0.1 M NaOH as stripping agent and an external phase pH of 0.5. Different water qualities have also been investigated showing that the type of water (deionized, distilled, or tap water) does not significantly influence the extraction rate. PMID:25915191

  19. Application of supported liquid membranes for removal of uranium from groundwater

    SciTech Connect

    Chiarizia, R.; Horwitz, E.P.; Rickert, P.G.; Hodgson, K.M.; Westinghouse Hanford Co., Richland, WA )

    1989-01-01

    The separation of uranium from Hanford site groundwater as studied by hollow-fiber supported liquid membranes, SLM. The carrier bis(2,4,4-trimethylpentyl)phosphinic acid, H(DTMPep), contained in the commercial extractant Cyanex{trademark} 272 was used as a membrane carrier, because of its selectivity for U over calcium and magnesium. The water soluble complexing agent, 1-hydroxyethane-1,1-diphosphonic acid, HEDPA, was used as stripping agent. Polypropylene hollow-fibers and n-dodecane were used as polymeric support and diluent, respectively. Laboratory scale hollow-fiber modules were employed in a recycling mode, using as feed synthetic groundwater at pH 2, to confirm the capability of the proposed SLM system to separate and concentrate U(VI) in the strip solution. Information was obtained on the U(VI) concentration factor and on the long-term performance of the SLMs. Encouraging results were obtained both with a conventional module and with a module containing a carrier solution reservoir. Industrial scale modules were used at Hanford to test the SLM separation of U(VI) from real contaminated groundwater. The uranium concentration was reduced from approximately 3500 ppB to about 1 ppB in a few hours. 9 refs., 8 figs., 4 tabs.

  20. Extraction of phenol using sulfuric acid salts of trioctylamine in a supported liquid membrane

    SciTech Connect

    Wang, M.L.; Hu, K.H. )

    1994-04-01

    The extraction of phenol by trioctylamine sulfate salts in a supported-liquid membrane (SLM) process was investigated. In the extraction process, a transport model, which included the film diffusion of phenol in the aqueous phase, the membrane diffusion within the SLM, and the interfacial chemical reaction, was built. The experimental parameters, such as the cell constant ([beta]), the diffusivity of (TOA)[sub 2]H[sub 2]SO[sub 4][center dot]PhOH in the SLM (D[sub c,b]), and the mass-transfer coefficient of phenol in the aqueous solution (K[sub L]), were determined from experiments. On the basis of the experimental data and the results obtained from the transport model, the rate-controlling step of the extraction of phenol by an SLM during permeation is discussed. The effects of the operating variables and parameters, such as the initial concentration of phenol in the aqueous phase, sulfuric acid, sodium hydroxide, and trioctylamine sulfate salts, on the extraction of phenol were examined.

  1. 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.

  2. 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

  3. Multiresidue determination of sulfonamides in a variety of biological matrices by supported liquid membrane with high pressure liquid chromatography-electrospray mass spectrometry detection.

    PubMed

    Msagati, Titus A M; Nindi, Mathew Muzi

    2004-09-01

    A high performance liquid chromatography (HPLC) coupled to a mass spectrometer (MS) was used for a simultaneous determination of 16 sulfonamide compounds spiked in water, urine, milk, and bovine liver and kidney tissues. Supported liquid membrane (SLM) made up of 5% tri-n-octylphosphine oxide (TOPO) dissolved in hexyl amine was used as a sample clean-up and/or enrichment technique. The sulfonamides mixture was made up of 5-sulfaminouracil, sulfaguanidine, sulfamethoxazole, sulfamerazine, sulfamethizole, sulfamethazine (sulfadimidine), sulfacetamide, sulfapyridine, sulfabenzamide, sulfamethoxypyridazine, sulfamonomethoxine, sulfadimethoxine sulfasalazine, sulfaquinoxaline, sulfadiazine, and sulfathiazole. Some of these compounds, such as, sulfaquinoxaline, sulfadiazine, sulfabenzamide, sulfathiazole and sulfapyridine failed to be trapped efficiently by the same liquid membrane (5% TOPO in hexylamine). The detection limits (DL) obtained were 1.8ppb for sulfaguanidine and sulfamerazine and between 3.3 and 10ppb in bovine liver and kidney tissues for the other sulfonamides that were successfully enriched with SLM; 2.1ppb for sulfaguanidine and sulfamerazine and between 7.5 and 15ppb in cow's urine, whereas the DL values in milk were 12.4ppb for sulfaguanidine and sulfamerazine and between 16.8 and 24.3 for the other compounds that were successfully enriched by the membrane. Several factors affecting the extraction efficiency during SLM enrichment, such as donor pH, acceptor pH, enrichment time and the membrane solvent were studied. PMID:18969572

  4. Determination of short-chain fatty acids in serum by hollow fiber supported liquid membrane extraction coupled with gas chromatography.

    PubMed

    Zhao, Guohua; Liu, Jing-Fu; Nyman, Margareta; Jönsson, Jan Ake

    2007-02-01

    A method based on hollow fiber supported liquid membrane extraction coupled with a gas chromatograph equipped with flame ionization detector (GC-FID) was developed for the determination of six short-chain fatty acids including acetic acid, propionic acid, i-butyric acid, n-butyric acid, i-valeric acid and n-valeric acid in serum. Hollow fiber supported liquid membrane extraction was employed for preconcentration and clean-up of the samples. The fatty acids were extracted from the acidic donor (diluted serum) into a liquid membrane formed in the wall of the hollow fiber with 10% tri-n-octylphoshphine oxide (TOPO) in di-n-hexyl ether, and then extracted back into a basic acceptor solution filled in the lumen of the hollow fiber. After being acidified with HCl, the acceptor was directly analyzed by GC-FID. The acceptor concentration, donor pH, membrane liquid and extracting time were optimized giving an enrichment factor up to 155 times. The good linearity (r(2)>0.980), reasonable recovery (87.2-121%), and satisfactory intra-assay (8.2-11.5%) and inter-assay (6.1-11.6%) precision illustrated the good performance of the present method. Limits of detection (LOD) ranged from 0.04 to 0.24 microM and limits of quantification (LOQ) varied from 0.13 to 0.80 microM. PMID:17070116

  5. Phospholipase A2-Induced Remodeling Processes on Liquid-Ordered/Liquid-Disordered Membranes Containing Docosahexaenoic or Oleic Acid: A Comparison Study.

    PubMed

    Georgieva, Rayna; Mircheva, Kristina; Vitkova, Victoria; Balashev, Konstantin; Ivanova, Tzvetanka; Tessier, Cedric; Koumanov, Kamen; Nuss, Philippe; Momchilova, Albena; Staneva, Galya

    2016-02-23

    Vesicle cycling, which is an important biological event, involves the interplay between membrane lipids and proteins, among which the enzyme phospholipase A2 (PLA2) plays a critical role. The capacity of PLA2 to trigger the budding and fission of liquid-ordered (L(o)) domains has been examined in palmitoyl-docosahexaenoylphosphatidylcholine (PDPC) and palmitoyl-oleoylphosphatidylcholine (POPC)/sphingomyelin/cholesterol membranes. They both exhibited a L(o)/liquid-disordered (L(d)) phase separation. We demonstrated that PLA2 was able to trigger budding in PDPC-containing vesicles but not POPC ones. The enzymatic activity, line tension, and elasticity of the membrane surrounding the L(o) domains are critical for budding. The higher line tension of Lo domains in PDPC mixtures was assigned to the greater difference in order parameters of the coexisting phases. The higher amount of lysophosphatidylcholine generated by PLA2 in the PDPC-containing mixtures led to a less-rigid membrane, compared to POPC. The more elastic L(d) membranes in PDPC mixtures exert a lower counteracting force against the L(o) domain bending. PMID:26794691

  6. Experimental and modeling study of human tympanic membrane motion in the presence of middle ear liquid.

    PubMed

    Zhang, Xiangming; Guan, Xiying; Nakmali, Don; Palan, Vikrant; Pineda, Mario; Gan, Rong Z

    2014-12-01

    Vibration of the tympanic membrane (TM) has been measured at the umbo using laser Doppler vibrometry and analyzed with finite element (FE) models of the human ear. Recently, full-field TM surface motion has been reported using scanning laser Doppler vibrometry, holographic interferometry, and optical coherence tomography. Technologies for imaging human TM motion have the potential to lead to using a dedicated clinical diagnosis tool for identification of middle ear diseases. However, the effect of middle ear fluid (liquid) on TM surface motion is still not clear. In this study, a scanning laser Doppler vibrometer was used to measure the full-field surface motion of the TM from four human temporal bones. TM displacements were measured under normal and disease-mimicking conditions with different middle ear liquid levels over frequencies ranging from 0.2 to 8 kHz. An FE model of the human ear, including the ear canal, middle ear, and spiral cochlea was used to simulate the motion of the TM in normal and disease-mimicking conditions. The results from both experiments and FE model show that a simple deflection shape with one or two major displacement peak regions of the TM in normal ear was observed at low frequencies (1 kHz and below) while complicated ring-like pattern of the deflection shapes appeared at higher frequencies (4 kHz and above). The liquid in middle ear mainly affected TM deflection shapes at the frequencies higher than 1 kHz.

  7. 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. PMID:24663947

  8. 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.

  9. Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography.

    PubMed

    Tao, Yong; Liu, Jing-Fu; Hu, Xia-Lin; Li, Hong-Cheng; Wang, Thanh; Jiang, Gui-Bin

    2009-08-28

    By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C(8)MIM][PF(6)] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH(2)PO(4) with 2M Na(2)SO(4); acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100microg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.

  10. Removal and recovery of metals and other materials by supported liquid membranes with strip dispersion.

    PubMed

    Ho, W S Winston

    2003-03-01

    This paper reviews recent advances in supported liquid membranes (SLMs) with strip dispersion for removal and recovery of metals including chromium, copper, zinc, and strontium; it also discusses potential applications of SLMs for removal and recovery of other materials, including cobalt and penicillin G. The technology for chromium that we developed, not only removes the Cr(VI) from about 100-1,000 ppm to less than 0.05 ppm in the treated effluent allowable for discharge or recycle, but also recovers the chromium product at a high concentration of about 20% Cr(VI) (62.3% Na(2)CrO(4)) suitable for resale or reuse. In other words, we have achieved the goals of zero discharge and no sludge. The stability of the SLM is ensured by a modified SLM with strip dispersion, where the aqueous strip solution is dispersed in the organic membrane solution in a mixer. The strip dispersion formed is circulated from the mixer to the membrane module to provide a constant supply of the organic solution to the membrane pores. The copper SLM system that we have identified, not only removed the copper from 150 ppm in the inlet feed to less than 0.15 ppm in the treated feed, but also recovered the copper at a high concentration of greater than 10,000 ppm in the strip solution. For the zinc SLM system identified, zinc at an inlet feed concentration of 550 ppm was removed to less than 0.3 ppm in the treated feed, whereas a high zinc concentration of more than 17,000 ppm was recovered in the strip solution. For strontium removal, we synthesized a family of new extractants, alkyl phenylphosphonic acids. The SLM removed radioactive (90)Sr to the target of 8 pCi/L or lower from feed solutions of 300-1,000 pCi/L. The SLM removed cobalt from about 525 ppm to 0.7 ppm in the treated feed solution, concentrating it to at least 30,000 ppm in the aqueous strip solution. Concerning penicillin G recovery, the SLM removed penicillin G from a feed of 8,840 ppm and concentrated it to a high concentration

  11. 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

  12. 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.

  13. 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.

  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. 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.

  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. Multiresidue determination of pesticides in industrial and fresh orange juice by hollow fiber microporous membrane liquid-liquid extraction and detection by liquid chromatography-electrospray-tandem mass spectrometry.

    PubMed

    Bedendo, Gizelle Cristina; Jardim, Isabel Cristina Sales Fontes; Carasek, Eduardo

    2012-01-15

    A procedure involving hollow fiber microporous membrane liquid-liquid extraction (HF-MMLLE) and detection by liquid chromatography with tandem mass spectrometry was developed and applied. The extraction is based on liquid-liquid microextraction with a polypropylene porous membrane as a solid support for the solvent. On the membrane walls the solvent forms a renewable liquid membrane which improves the trueness of the method and promotes the sample clean-up. The applicability of this method was evaluated through the simultaneous extraction of 18 pesticides of different classes: polar organophosphates, carbamates, neonicotinoids, amides, pyrimidines, benzimidazoles and triazoles in industrial and fresh orange juice. The parameters affecting the extraction efficiency were optimized by multivariable designs. Under optimized conditions, analytes were concentrated onto 1.5 cm long microporous membranes placed directly into the sample containing 9mL of juice at pH 7.0, 4 g of ammonium sulfate and 400 μL of toluene:ethyl acetate (85:15, v/v). The best extraction conditions were achieved at 25°C with 35 min of extraction time. The analyte desorption was carried out using 50 μL of methanol:acetone (50:50, v/v) for 2 min in an ultrasonic bath. Limits of detection ranging between 0.003-0.33 mgL(-1), 0.003-0.35 mg L(-1) and 0.003-0.15 mgL(-1) were obtained for the carton orange juice, carton light orange juice and fresh orange juice samples, respectively. Good repeatability (lower than 7.6%) was obtained for all three sample types. The method was applied to five different juice samples containing soybean extract, orange pulp, nectar, light juice and fresh orange juice. The results suggest that the proposed method represents a very simple and low-cost alternative microextraction procedure rendering adequate limits of quantification for the determination of these pesticides in juice samples.

  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

    2012-03-01

    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. 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. PMID:26101101

  1. 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.

  2. 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

    2016-01-01

    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. PMID:27533852

  3. Glycine enhanced separation of Co(II) and Ni(II) with bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) by liquid-liquid extraction and supported liquid membranes

    SciTech Connect

    Reichley-Yinger, L.; Danesi, P.R.

    1985-01-01

    The extraction behavior of Co and Ni ions from aqueous nitrate solution containing glycine, and their separation by liquid-liquid extraction and supported liquid membranes (SLMs) has been studied. The separation factor between the two metals is greatly enhanced by the presence of glycine. The enhancement is due to the preferential complexation of the Ni ions by glycine. The conditional equilibrium constants of the extraction reactions and the SLM permeability coefficients have been measured. The results indicate that metal glycinate complexes are not extracted and that in presence of glycine very clean Co-Ni separation can be obtained in a single SLM pass.

  4. Evaluation of liquid-liquid microextraction using polypropylene microporous membranes for the determination of organophosphorus flame retardants and plasticizers in water samples.

    PubMed

    García-López, M; Rodríguez, I; Cela, R

    2008-09-12

    In this work, the suitability of the microporous membrane liquid-liquid extraction (MMLLE) technique for the concentration of several organophosphate esters (OPs) in water samples is assessed. Analytes were first extracted into a few microlitres of an organic solvent, immobilized in the pores of a hollow polypropylene membrane, and then determined by gas chromatography with nitrogen-phosphorus detection (GC-NPD). Main parameters controlling the efficiency of the extraction step were identified and their effects on the performance of the technique discussed. Under final working conditions, 2 cm long polypropylene membranes, containing about 7 microL of octanol in the pores, were dipped in a glass vial filled with 115 mL of water with a 30% of sodium chloride. Extractions were carried out for 12h, at room temperature, under magnetic stirring. After that, analytes were recovered from the membrane with 0.2 mL of ethyl acetate. This extract was mixed with the internal standard (50 microL of a tripentyl phosphate solution in the same solvent) and finally reduced to ca. 50 microL. Overall enrichment factors for the optimized method ranged from 35 to 1400 times, and the achieved limits of quantification from 0.008 to 0.12 ng mL(-1), depending on the considered compound. Globally, the method showed an acceptable linearity and precision for all species, except for tris(2-ethylhexyl) phosphate (TEHP). Performance of the MMLLE approach is compared with that reported for other solid- and liquid-phase microextraction techniques and its suitability for the analysis of real water samples discussed. PMID:18724988

  5. 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.

  6. 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.

  7. 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).

  8. 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.

  9. 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.

  10. Liquid crystals and their interactions with colloidal particles and phospholipid membranes: Molecular simulation studies

    NASA Astrophysics Data System (ADS)

    Kim, Evelina B.

    Experimentally, liquid crystals (LC) can be used as the basis for optical biomolecular sensors that rely on LC ordering. Recently, the use of LC as a reporting medium has been extended to investigations of molecular scale processes at lipid laden aqueous-LC interfaces and at biological cell membranes. In this thesis, we present two related studies where liquid crystals are modelled at different length scales. We examine (a) the behavior of nanoscopic colloidal particles in LC systems, using Monte Carlo (MC) molecular simulations and a mesoscopic dynamic field theory (DyFT); and (b) specific interactions of two types of mesogens with a model phospholipid bilayer, using atomistic molecular dynamics (MD) at the A-nm scale. In (a), we consider colloidal particles suspended in a LC, confined between two walls. We calculate the colloid-substrate and colloid-colloid potentials of mean force (PMF). For the MC simulations, we developed a new technique (ExEDOS or Expanded Ensemble Density Of States) that ensures good sampling of phase space without prior knowledge of the energy landscape of the system. Both results, simulation and DyFT, indicate a repulsive force acting between a colloid and a wall. In contrast, both techniques indicate an overall colloid-colloid attraction and predict a new topology of the disclination lines that arises when the particles approach each other. In (b), we find that mesogens (pentylcyanobiphenyl [5CB] or difluorophenyl-pentylbicyclohexyl [5CF]) preferentially partition from the aqueous phase into a dipalmitoylphosphatidylcholine (DPPC) bilayer. We find highly favorable free energy differences for partitioning (-18kBT for 5CB, -26k BT for 5CF). We also simulated fully hydrated bilayers with embedded 5CB or 5CF at concentrations used in recent experiments (6 mol% and 20 mol%). The presence of mesogens in the bilayer enhances the order of lipid acyl tails and changes the spatial and orientational arrangement of lipid headgroup atoms. A stronger

  11. 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)

  12. 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

  13. 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

    2016-06-01

    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

  14. Novel analytical procedure using a combination of hollow fiber supported liquid membrane and dispersive liquid-liquid microextraction for the determination of aflatoxins in soybean juice by high performance liquid chromatography - Fluorescence detector.

    PubMed

    Simão, Vanessa; Merib, Josias; Dias, Adriana N; Carasek, Eduardo

    2016-04-01

    This study describes a combination between hollow fiber membrane and dispersive liquid-liquid microextraction for determination of aflatoxins in soybean juice by HPLC. The main advantage of this approach is the use of non-chlorinated solvent and small amounts of organic solvents. The optimum extraction conditions were 1-octanol as immobilized solvent; toluene and acetone at 1:5 ratio as extraction and disperser solvents (100 μL), NaCl at 2% of the sample volume and extraction time of 60 min. The optimal condition for the liquid desorption was 150 μL acetonitrile:water (50:50 v/v) and desorption time of 20 min. The linear range varied from 0.03 to 21 μg L(-1), with R(2) coefficients ranging from 0.9940 to 0.9995. The limits of detection and quantification ranged from 0.01 μg L(-1) to 0.03 μg L(-1) and from 0.03 μg L(-1) to 0.1 μg L(-1), respectively. Recovery tests ranged from 72% to 117% and accuracy between 12% and 18%.

  15. 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. PMID:27178937

  16. Implementation of droplet-membrane-droplet liquid-phase microextraction under stagnant conditions for lab-on-a-chip applications.

    PubMed

    Sikanen, Tiina; Pedersen-Bjergaard, Stig; Jensen, Henrik; Kostiainen, Risto; Rasmussen, Knut Einar; Kotiaho, Tapio

    2010-01-25

    In the current work, droplet-membrane-droplet liquid-phase microextraction (LPME) under totally stagnant conditions was presented for the first time. Subsequently, implementation of this concept on a microchip was demonstrated as a miniaturized, on-line sample preparation method. The performance level of the lab-on-a-chip system with integrated microextraction, capillary electrophoresis (CE) and laser-induced fluorescence (LIF) detection in a single miniaturized device was preliminarily investigated and characterized. Extractions under stagnant conditions were performed from 3.5 to 15 microL sample droplets, through a supported liquid membrane (SLM) sustained in the pores of a small piece of a flat polypropylene membrane, and into 3.5-15 microL of acceptor droplet. The basic model analytes pethidine, nortriptyline, methadone, haloperidol, and loperamide were extracted from alkaline sample droplets (pH 12), through 1-octanol as SLM, and into acidified acceptor droplets (pH 2) with recoveries ranging between 13 and 66% after 5 min of operation. For the acidic model analytes Bodipy FL C(5) and Oregon Green 488, the pH conditions were reversed, utilizing an acidic sample droplet and an alkaline acceptor droplet, and 1-octanol as SLM. As a result, recoveries for Bodipy FL C(5) and Oregon Green 488 from human urine were 15 and 25%, respectively.

  17. 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.

  18. Ultrastructural preservation of plasma membranes by non-lethal slow freezing to liquid nitrogen temperature.

    PubMed

    Fujikawa, S; Miura, K

    1987-02-01

    Secondary hyphae of Lyophyllum ulmarium were shown to tolerate slow freezing, which allowed extracellular freezing, to -196 degrees C. A freeze-fracture study showed that under this non-lethal freezing condition, the plasma membrane of the secondary hyphae did not show any ultrastructural changes as compared with the control, except gross cellular shrinkage. Tertiary hyphae of Lyophyllum ulmarium, on the other hand, were completely injured by slow freezing to -196 degrees C, and the plasma membrane showed distinct intramembrane particle aggregation as a result of direct membrane contact caused by severe cellular deformation. It is suggested that the absence of freezing injury in the secondary hyphae was due to ultrastructural preservation of the plasma membrane, which resulted from avoidance of severe cellular deformation, while occurrence of freezing injury in the tertiary hyphae is considered to be due to ultrastructural changes in the plasma membrane caused by severe cellular deformation. PMID:3568151

  19. A strategy for the systematic development of a liquid chromatographic mass spectrometric screening method for polymer electrolyte membrane degradation products using isocratic and gradient phase optimized liquid chromatography.

    PubMed

    Zedda, M; Tuerk, J; Teutenberg, T; Peil, S; Schmidt, T C

    2009-12-18

    Within the scope of research for target and non-target LC-MS/MS analysis of membrane degradation products of polymer electrolyte membrane fuel cells, a systematic method development for the separation of structurally similar compounds was performed by phase optimized liquid chromatography. Five different stationary phases with different selectivities were used. Isocratic separation for 4-hydroxybenzoic acid, isophthalic acid, terephthalic acid, 4-hydroxybenzaldehyde and 4-formylbenzoic acid was achieved on a C18 and a Phenyl phase. Using the PRISMA model the separation efficiency was optimized. This was achieved on a serially connected mixed stationary phase composed of 30 mm C18, 150 mm Phenyl and 60 mm C30. For the LC-MS screening of unknown degradation products from polymer electrolyte membranes in the product water of a fuel cell, a solvent gradient is mandatory for less polar or later eluting compounds. By means of 4-mercaptobenzoic acid it could be shown that a solvent gradient can be applied in order to elute later eluting compounds in a short time. The adaptability of this method for the qualitative analysis by target and non-target LC-MS/MS screening has been shown by means of 4-hydroxybenzoic acid. The combination of solvent gradient and isocratic conditions makes this approach attractive for the purpose of a screening method for known and unknown analytes in a water sample.

  20. 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

  1. Ion-exchange-membrane-based enzyme micro-reactor coupled online with liquid chromatography-mass spectrometry for protein analysis.

    PubMed

    Zhou, Zhigui; Yang, Youyou; Zhang, Jialing; Zhang, Zhengxiang; Bai, Yu; Liao, Yiping; Liu, Huwei

    2012-04-01

    In this article, we developed a membrane-based enzyme micro-reactor by directly using commercial polystyrene-divinylbenzene cation-exchange membrane as the support for trypsin immobilization via electrostatic and hydrophobic interactions and successfully applied it for protein digestion. The construction of the reactor can be simply achieved by continuously pumping trypsin solution through the reactor for only 2 min, which was much faster than the other enzyme immobilization methods. In addition, the membrane reactor could be rapidly regenerated within 35 min, resulting in a "new" reactor for the digestion of every protein sample, completely eliminating the cross-interference of different protein samples. The amount and the activity of immobilized trypsin were measured, and the repeatability of the reactor was tested, with an RSD of 3.2% for the sequence coverage of cytochrome c in ten digestion replicates. An integrated platform for protein analysis, including online protein digestion and peptide separation and detection, was established by coupling the membrane enzyme reactor with liquid chromatography-quadrupole time-of-flight mass spectrometry. The performance of the platform was evaluated using cytochrome c, myoglobin, and bovine serum albumin, showing that even in the short digestion time of several seconds the obtained sequence coverages was comparable to or higher than that with in-solution digestion. The system was also successfully used for the analysis of proteins from yeast cell lysate.

  2. 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.

  3. 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

  4. Selective transport of silver ion through a supported liquid membrane using hexathia-18-crown-6 as carrier.

    PubMed

    Shamsipur, M; Azimi, G; Mashhadizadeh, M H; Madaeni, S S

    2001-04-01

    A facile supported liquid membrane (SLM) system for the selective and efficient transport of silver ion is introduced. The SLM used is a thin porous polyvinyldifluoride membrane impregnated with hexathia-18-crown-6 (HT18C6) dissolved in nitrophenyloctyl ether. HT18C6 acts as a specific carrier for the uphill transport of Ag+ ion as its picrate ion paired complex through the SLM. In the presence of thiosulfate ion as a suitable stripping agent in the strip solution, transport of silver occurs almost quantitatively after 4 h. The selectivity and efficiency of silver transport from aqueous solutions containing other Mn+ cations such as Mg2+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+, Hg2+, Fe3+ and Cr3+ ions were investigated. PMID:11990563

  5. Permeation of iridium(IV) and metal impurity chlorocomplexes through a supported liquid membrane designed for rhodium separation

    SciTech Connect

    Ashrafizadeh, S.N.; Demopoulos, G.P.; Rovira, M.; Sastre, A.M.

    1998-06-01

    A supported liquid membrane (SLM) system previously designed for Rh separation has been examined for its capability to reject the metal impurities which are commonly encountered in industrial Rh chloride solutions. Special attention was paid to Ir(IV) chlorocomplexes and their extraction/transport behavior against both conventional solvent extraction and supported liquid membrane systems of Kelex 100. A lab-scale SLM cell with an effective membrane area of 44 cm{sup 2} was used to conduct the SLM permeation tests. The SLM was composed of a Gore-Tex polymer substrate impregnated with an organic solution of Kelex 100, tridecanol, and kerosene. The impurities tested [in addition to Ir(IV)] were AG(I), As(V), Bi(III), Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II), Pd(II), Pt(IV), Se(IV), Te(IV), and Zn(II). These impurities, based on their response against the SLM, were classified into three groups, i.e., those permeated through [Zn(II), Pb(II), Cd(II), Bi(III), Te(IV), and Ir(IV)], those nonpermeated at all [Ni(II), Co(II), As(V), Se(IV), Cu(II), and Fe(III)], and those blocking the membrane [Pt(IV), Pd(II), Ag(I), Pb(II), and Bi(III)]. The SLM was not capable of discriminating between Rh(III) and Ir(IV) transport at the optimum operating conditions. Complementary upstream and downstream processes are required to separate the impurities from the feed and the product solutions, respectively. Overall, this work revealed the great limitations of SLMs as effective and potentially useful separation media for the extraction of metals from industrial-like multicomponent aqueous feed solutions.

  6. 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

  7. Simulation studies of ammonia removal from water in a membrane contactor under liquid-liquid extraction mode.

    PubMed

    Mandowara, Amish; Bhattacharya, Prashant K

    2011-01-01

    Simulation studies were carried out, in an unsteady state, for the removal of ammonia from water via a membrane contactor. The contactor had an aqueous solution of NH(3) in the lumen and sulphuric acid in the shell side. The model equations were developed considering radial and axial diffusion and convection in the lumen. The partial differential equations were converted by the finite difference technique into a series of stiff ordinary differential equations w.r.t. time and solved using MATLAB. Excellent agreement was observed between the simulation results and experimental data (from the literature) for a contactor of 75 fibres. Excellent agreement was also observed between the simulation results and laboratory-generated data from a contactor containing 10,200 fibres. Our model is more suitable than the plug-flow model for designing the operation of the membrane contactor. The plug-flow model over-predicts the fractional removal of ammonia and was observed to be limited when designing longer contactors.

  8. 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.

  9. 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

  10. 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...

  11. 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 ...

  12. Interaction of the organic tin chloride with the liquid model membranes

    NASA Astrophysics Data System (ADS)

    Podolak, M.; Engel, G.; Man, D.

    2007-08-01

    The objective of the work was to investigate the effect of organic tin chloride (C3H7)3SnCl on the electric parameters of membranes in the form of filters of the company Synpor (Czech Republic) impregnated with various fatty acids, dissolved with carbon tetrachloride (CCl4). Three carboxylic acids were used in the study: palmitic, arachidic and oleic, and dissolvent of the acids (CCl4) as well as butylene ester of lauric acid. In all cases, introduction of tin chloride of constant concentration amounting to 0.15 mM to the measurement chamber resulted in induction of membrane voltage. In case of pure lauric acid and CCl4, the voltage reached the maximum value and then decreased to a certain constant value. In the case of all acids dissolved in CCl4, the voltage increased only up to a certain constant value. Voltage drop (below the value) was observed after application of appropriately high concentration of tin chloride, in case of membranes impregnated with the mixture of lauric acid ester with CCl4 and palmitic acid with CCl4. The study also demonstrated that electrical resistance of membranes impregnated with carboxylic acid increased in the presence of tin chloride and decreased in case of membranes impregnated with lauric acid ester. However, electric capacities of membranes did not significant change.

  13. Liquid-Like Water Confined in Stacks of Biological Membranes at 200 K and Its Relation to Protein Dynamics

    PubMed Central

    Weik, M.; Lehnert, U.; Zaccai, G.

    2005-01-01

    Confined water is of considerable current interest owing to its biophysical importance and relevance to cryopreservation. It can be studied in its amorphous or supercooled state in the “no-man's land”, i.e., in the temperature range between 150 and 235 K, in which bulk water is always crystalline. Amorphous deuterium oxide (D2O) was obtained in the intermembrane spaces of a stack of purple membranes from Halobacterium salinarum by flash cooling to 77 K. Neutron diffraction showed that upon heating to 200 K the intermembrane water space decreased sharply with an associated strengthening of ice diffraction, indicating that water beyond the first membrane hydration layer flowed out of the intermembrane space to form crystalline ice. It was concluded that the confined water undergoes a glass transition at or below 200 K to adopt an ultraviscous liquid state from which it crystallizes to form ice as soon as it finds itself in an unconfined, bulk-water environment. Our results provide model-free evidence for translational diffusion of confined water in the no-man's land. Potential effects of the confined-water glass transition on nanosecond membrane dynamics were investigated by incoherent elastic neutron scattering experiments. These revealed no differences between flash-cooled and slow-cooled samples (in the latter, the intermembrane space at temperatures <250 K is occupied only by the first membrane hydration layers), with dynamical transitions at 150 and 260 K, but not at 200 K, suggesting that nanosecond membrane dynamics are not sensitive to the state of the water beyond the first hydration shell at cryotemperatures. PMID:16055529

  14. 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.

  15. Effects of pyrenebutyrate on the translocation of arginine-rich cell-penetrating peptides through artificial membranes: recruiting peptides to the membranes, dissipating liquid-ordered phases, and inducing curvature.

    PubMed

    Katayama, Sayaka; Nakase, Ikuhiko; Yano, Yoshiaki; Murayama, Tomo; Nakata, Yasushi; Matsuzaki, Katsumi; Futaki, Shiroh

    2013-09-01

    Arginine-rich cell-penetrating peptides, including octaarginine (R8) and HIV-1 TAT peptides, have the ability to translocate through cell membranes and transport exogenous bioactive molecules into cells. Hydrophobic counteranions such as pyrenebutyrate (PyB) have been reported to markedly promote the membrane translocation of these peptides. In this study, using model membranes having liquid-ordered (Lo) and liquid-disordered (Ld) phases, we explored the effects of PyB on the promotion of R8 translocation. Confocal microscopic observations of giant unilamellar vesicles (GUVs) showed that PyB significantly accelerated the accumulation of R8 on membranes containing negatively charged lipids, leading to the internalization of R8 without collapse of the GUV structures. PyB displayed an alternative activity, increasing the fluidity of the negatively charged membranes, which diminished the distinct Lo/Ld phase separation on GUVs. This was supported by the decrease in fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH). Additionally, PyB induced membrane curvature, which has been suggested as a possible mechanism of membrane translocation for R8. Taken together, our results indicate that PyB may have multiple effects that promote R8 translocation through cell membranes.

  16. 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.

  17. 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

  18. Photoswitchable gas permeation membranes based on azobenzene-doped liquid crystals II. Permeation-switching characterization under variable volume and variable pressure conditions

    NASA Astrophysics Data System (ADS)

    Glowacki, E.; Hunt, K.; Abud, D.; Marshall, K. L.

    2010-08-01

    Stimuli-responsive gas permeation membranes hold substantial potential for industrial processes as well as in analytical and screening applications. Such "smart" membrane systems, although prevalent in liquid mass-transfer manipulations, have yet to be realized for gas applications. We report our progress in developing gas permeation membranes in which liquid crystalline (LC) phases afford the active region of permeation. To achieve rapid and reversible switching between LC and isotropic permeation states, we harnessed the photomechanical action of mesogenic azobenzene dyes that can produce isothermal nematic-isotropic transitions. Both polymeric and low-molecular-weight LC materials were tested. Three different dye-doped LC mixtures with mesogenic azo dyes were infused into commercially available track-etched porous membranes with regular cylindrical pores (0.4 to 10.0 μm). Photoinduced isothermal phase changes in the imbibed material produced large and fully reversible changes in the permeability of the membrane to nitrogen with 5 s of irradiation at 2 mW/cm2. Using two measurement tools constructed in-house, the permeability of the photoswitched membranes was determined by both variable-pressure and variable-volume methods. Both the LC and photogenerated isotropic states demonstrate a linear permeability/pressure (ideal sorption) relationship, with up to a 16-fold difference in their permeability coefficients. Liquid crystal compositions can be chosen such that the LC phase is more permeable than the isotropic-or vice versa. This approach is the first system offering reversible tunable gas permeation membranes.

  19. Lipid Raft-Mediated Membrane Tethering and Delivery of Hydrophobic Cargos from Liquid Crystal-Based Nanocarriers.

    PubMed

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

    2016-04-20

    A main goal of bionanotechnology and nanoparticle (NP)-mediated drug delivery (NMDD) continues to be the development of novel biomaterials that can controllably modulate the activity of the NP-associated therapeutic cargo. One of the desired subcellular locations for targeted delivery in NMDD is the plasma membrane. However, the controlled delivery of hydrophobic cargos to the membrane bilayer poses significant challenges including cargo precipitation and lack of specificity. Here, we employ a liquid crystal NP (LCNP)-based delivery system for the controlled partitioning of a model dye cargo from within the NP core into the plasma membrane bilayer. During synthesis of the NPs, the water-insoluble model dye cargo, 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO), was efficiently incorporated into the hydrophobic LCNP core as confirmed by multiple spectroscopic analyses. Conjugation of a PEGylated cholesterol derivative to the NP surface (DiO-LCNP-PEG-Chol) facilitated the localization of the dye-loaded NPs to lipid raft microdomains in the plasma membrane in HEK 293T/17 cell. Analysis of DiO cellular internalization kinetics revealed that when delivered as a LCNP-PEG-Chol NP, the half-life of DiO membrane residence time (30 min) was twice that of free DiO (DiO(free)) (15 min) delivered from bulk solution. Time-resolved laser scanning confocal microscopy was employed to visualize the passive efflux of DiO from the LCNP core and its insertion into the plasma membrane bilayer as confirmed by Förster resonance energy transfer (FRET) imaging. Finally, the delivery of DiO as a LCNP-PEG-Chol complex resulted in the attenuation of its cytotoxicity; the NP form of DiO exhibited ∼30-40% less toxicity compared to DiO(free). Our data demonstrate the utility of the LCNP platform as an efficient vehicle for the combined membrane-targeted delivery and physicochemical modulation of molecular cargos using lipid raft-mediated tethering.

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

    PubMed

    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.

  1. 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.

  2. 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

  3. 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.

  4. Determination of ketamine, norketamine and dehydronorketamine in urine by hollow-fiber liquid-phase microextraction using an essential oil as supported liquid membrane.

    PubMed

    Bairros, André Valle de; Lanaro, Rafael; Almeida, Rafael Menck de; Yonamine, Mauricio

    2014-10-01

    Here, we present a method for the determination of ketamine (KT) and its main metabolites, norketamine (NK) and dehydronorketamine (DHNK) in urine samples by using hollow-fiber liquid-phase microextraction (HF-LPME) in the three-phase mode. The fiber pores were filled with eucalyptus essential oil and a solution of 1.0mol/L of HCl was introduced into the lumen of the fiber (acceptor phase). The fiber was submersed in the alkalinized urine containing 10% NaCl, and the system was submitted to lateral shaking (2400rpm) during 30min. Acceptor phase was withdrawn from the fiber, dried and the residue was then derivatized with trifluoroacetic anhydride (TFAA) for further determination by gas chromatography-mass spectrometry (GC-MS). The calibration curves were linear over the specified range and limits of detection (LoDs) obtained for KT, NK and DHNK were below the cut-off value (1.0ng/mL) recommended by the United Nations Office on Drugs and Crime (UNODC). A totally "green chemistry" approach of the sample extraction was obtained by using essential oil as a supported liquid membrane in HF-LPME. The developed method was successfully validated and applied to urine samples collected from two clinical cases in which KT was suspected to be involved.

  5. Determination of ketamine, norketamine and dehydronorketamine in urine by hollow-fiber liquid-phase microextraction using an essential oil as supported liquid membrane.

    PubMed

    Bairros, André Valle de; Lanaro, Rafael; Almeida, Rafael Menck de; Yonamine, Mauricio

    2014-10-01

    Here, we present a method for the determination of ketamine (KT) and its main metabolites, norketamine (NK) and dehydronorketamine (DHNK) in urine samples by using hollow-fiber liquid-phase microextraction (HF-LPME) in the three-phase mode. The fiber pores were filled with eucalyptus essential oil and a solution of 1.0mol/L of HCl was introduced into the lumen of the fiber (acceptor phase). The fiber was submersed in the alkalinized urine containing 10% NaCl, and the system was submitted to lateral shaking (2400rpm) during 30min. Acceptor phase was withdrawn from the fiber, dried and the residue was then derivatized with trifluoroacetic anhydride (TFAA) for further determination by gas chromatography-mass spectrometry (GC-MS). The calibration curves were linear over the specified range and limits of detection (LoDs) obtained for KT, NK and DHNK were below the cut-off value (1.0ng/mL) recommended by the United Nations Office on Drugs and Crime (UNODC). A totally "green chemistry" approach of the sample extraction was obtained by using essential oil as a supported liquid membrane in HF-LPME. The developed method was successfully validated and applied to urine samples collected from two clinical cases in which KT was suspected to be involved. PMID:24810678

  6. Templated electrodeposition of silver nanowires in a nanoporous polycarbonate membrane from a nonaqueous ionic liquid electrolyte

    NASA Astrophysics Data System (ADS)

    Kazeminezhad, I.; Barnes, A. C.; Holbrey, J. D.; Seddon, K. R.; Schwarzacher, W.

    2007-03-01

    Template electrodeposition has been used to prepare a wide range of nanostructures but has generally been restricted to aqueous electrolytes. We report the deposition of silver nanowires in a commercial nuclear track-etched polycarbonate template from the nonaqueous ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) using silver electrochemically dissolved from the anode. Transmission electron microscopy (TEM) shows that the nanowires have a very high aspect ratio with an average diameter of 80 nm and length of 5 μm. Ionic liquid electrolytes should greatly extend the range of metals that can be electrodeposited as nanowires using templates.

  7. 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.

  8. X-ray and Electrochemical Impedance Spectroscopy Diagnostic Investigations of Liquid Water in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

    NASA Astrophysics Data System (ADS)

    Antonacci, Patrick

    In this thesis, electrochemical impedance spectroscopy (EIS) and synchrotron x-ray radiography were utilized to characterize the impact of liquid water distributions in polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layers (GDLs) on fuel cell performance. These diagnostic techniques were used to quantify the effects of liquid water visualized on equivalent resistances measured through EIS. The effects of varying the thickness of the microporous layer (MPL) of GDLs were studied using these diagnostic techniques. In a first study on the feasibility of this methodology, two fuel cell cases with a 100 microm-thick and a 150 microm-thick MPL were compared under constant current density operation. In a second study with 10, 30, 50, and 100 microm-thick MPLs, the liquid water in the cathode substrate was demonstrated to affect mass transport resistance, while the liquid water content in the anode (from back diffusion) affected membrane hydration, evidenced through ohmic resistance measurements.

  9. 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

  10. Polymeric liquid membrane electrodes incorporated with undecylcalix[4]- resorcinarene for screening of neutral forms of diaminobenzene isomers.

    PubMed

    Kurzatkowska, Katarzyna; Radecka, Hanna; Dehaen, Wim; Wasowicz, Michal; Grzybowska, Izabela; Radecki, Jerzy

    2007-08-01

    The PVC supported liquid membrane electrodes incorporated with undecylcalix[4]resorcinarene (UDC[4]Rene) generates a cationic potentiometric response after stimulation by neutral (unprotonated) form of diaminobenzene isomers. The potentiometric signals were generated upon the formation of supramolecular complex between the UDC[4]Rene (host) and diaminobenzene (guest) at the organic-aqueous interface. In this paper for the first time we report the generation of cationic potential signal by electrode incorporated with host molecule possessing oxygen as a heteroatom, after stimulation with neutral guest containing nitrogen in its structure We also broaden the family of receptor molecules, which are able to generate charge separation at the organic/aqueous interface after interaction with uncharged molecules. The results obtained confirm the possibility of applying this potentiometric method for the screening of diaminobenzene isomers identified recently as allergens and endocrine disrupting chemicals. PMID:17979643

  11. 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.

  12. Ultrasensitive determination of cadmium in seawater by hollow fiber supported liquid membrane extraction coupled with graphite furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Peng, Jin-feng; Liu, Rui; Liu, Jing-fu; He, Bin; Hu, Xia-lin; Jiang, Gui-bin

    2007-05-01

    A new procedure, based on hollow fiber supported liquid membrane preconcentration coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection, was developed for the determination of trace Cd in seawater samples. With 1-octanol that contained a mixture of dithizone (carrier) and oleic acid immobilized in the pores of the polypropylene hollow fiber as a liquid membrane, Cd was selectively extracted from water samples into 0.05 M HNO 3 that filled the lumen of the hollow fiber as a stripping solution. The main extraction related parameters were optimized, and the effects of salinity and some coexisting interferants were also evaluated. Under the optimum extraction conditions, an enrichment factor of 387 was obtained for a 100-mL sample solution. In combination with graphite furnace atomic absorption spectrometry, a very low detection limit (0.8 ng L - 1 ) and a relative standard deviation (2.5% at 50 ng L - 1 level) were achieved. Five seawater samples were analyzed by the proposed method without dilution, with detected Cd concentration in the range of 56.4-264.8 ng L - 1 and the relative spiked recoveries over 89%. For comparison, these samples were also analyzed by the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method after a 10-fold dilution for matrix effect elimination. Statistical analysis with a one-way ANOVA shows no significant differences (at 0.05 level) between the results obtained by the proposed and ICP-MS methods. Additionally, analysis of certified reference materials (GBW (E) 080040) shows good agreement with the certified value. These results indicate that this present method is very sensitive and reliable, and can effectively eliminate complex matrix interferences in seawater samples.

  13. 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. PMID:26653501

  14. Water transport in water-in-oil-in-water liquid emulsion membrane system for the separation of lactic acid

    SciTech Connect

    Mok, Y.S.; Lee, W.K. )

    1994-03-01

    Liquid emulsion membranes (LEMs) were applied to the separation of lactic acid from an aqueous feed phase, and water transport (swelling) was investigated during the separation. Considering that as lactic acid was extracted into the internal stripping phase, osmotic pressure difference across the membrane was varied, the water transfer coefficient was evaluated. The water transfer coefficient was larger at higher carrier concentration and initial lactic acid concentration, which means that emulsion swelling can also be mediated by solute/carrier complexes although it is, in general, osmotically induced. The appropriate LEM formulation was given for separation and concentration of lactic acid. If both separation and concentration are desired, evidently emulsion swelling should be considered in conjunction with the transport rate of lactic acid. It was observed that the separated solute concentration in the internal phase was lowered due to swelling during the operation. Nevertheless, lactic acid could be concentrated in the internal phase more than 6 times in specific conditions, indicating that as the volume ratio of external phase to internal phase is increased, a still higher concentration in the internal phase can be obtained. 22 refs., 10 figs., 4 tabs.

  15. Combined photocatalysis and membrane bioreactor for the treatment of feedwater containing thin film transistor-liquid crystal display discharge.

    PubMed

    You, Sheng-Jie; Semblante, Galilee Uy; Chen, Yu-Pu; Chang, Tien-Chin

    2015-01-01

    The nitrogen content of waste water generated by the thin film transistor-liquid crystal display (TFT-LCD) industry is not satisfactorily removed through the conventional aerobic-activated sludge process. In this study, the performance of three reactors – suspended type TiO2 membrane photoreactor (MPR), anoxic/oxic membrane bioreactor (AOMBR), and their combination (MPR-AOMBR) – was evaluated using feedwater containing TFT-LCD discharge. The parameters that maximized monoethanolamine (MEA) removal in the MPR were continuous ultraviolet (UV) irradiation and pH 11. Among the tested loadings, 0.1 g/l of TiO2 promoted MEA removal but degradation rate may further increase with photocatalyst concentration. The nitrified sludge recycle ratio R of the AOMBR was adjusted to 1.5 to minimize the amount of nitrate in the effluent. The AOMBR greatly decreased chemical oxygen demand and MEA, but removed only 32.7% of tetramethyl ammonium hydroxide (TMAH). The MPR was configured as the pre-treatment unit for AOMBR, and the combined MPR-AOMBR has improved TMAH removal by 80.1%. The MPR bolstered performance by decomposing slowly biodegradable compounds, and had no negative effects on denitrification and carbon removal. PMID:25952015

  16. Combined photocatalysis and membrane bioreactor for the treatment of feedwater containing thin film transistor-liquid crystal display discharge.

    PubMed

    You, Sheng-Jie; Semblante, Galilee Uy; Chen, Yu-Pu; Chang, Tien-Chin

    2015-01-01

    The nitrogen content of waste water generated by the thin film transistor-liquid crystal display (TFT-LCD) industry is not satisfactorily removed through the conventional aerobic-activated sludge process. In this study, the performance of three reactors – suspended type TiO2 membrane photoreactor (MPR), anoxic/oxic membrane bioreactor (AOMBR), and their combination (MPR-AOMBR) – was evaluated using feedwater containing TFT-LCD discharge. The parameters that maximized monoethanolamine (MEA) removal in the MPR were continuous ultraviolet (UV) irradiation and pH 11. Among the tested loadings, 0.1 g/l of TiO2 promoted MEA removal but degradation rate may further increase with photocatalyst concentration. The nitrified sludge recycle ratio R of the AOMBR was adjusted to 1.5 to minimize the amount of nitrate in the effluent. The AOMBR greatly decreased chemical oxygen demand and MEA, but removed only 32.7% of tetramethyl ammonium hydroxide (TMAH). The MPR was configured as the pre-treatment unit for AOMBR, and the combined MPR-AOMBR has improved TMAH removal by 80.1%. The MPR bolstered performance by decomposing slowly biodegradable compounds, and had no negative effects on denitrification and carbon removal.

  17. Mathematical modeling of a carrier-mediated transport process in a liquid membrane.

    PubMed

    Ganesan, Subramanian; Anitha, Shanmugarajan; Subbiah, Alwarappan; Rajendran, Lakshmanan

    2013-06-01

    An analysis of the reaction diffusion in a carrier-mediated transport process through a membrane is presented. A simple approximate analytical expression of concentration profiles is derived in terms of all dimensionless parameters. Furthermore, in this work we employ the homotopy perturbation method to solve the nonlinear reaction-diffusion equations. Moreover, the analytical results have been compared to the numerical simulation using the Matlab program. The simulated results are comparable with the appropriate theories. The results obtained in this work are valid for the entire solution domain.

  18. 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. PMID:26753984

  19. 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.

  20. Electromembrane extraction of polar basic drugs from plasma with pure bis(2-ethylhexyl) phosphite as supported liquid membrane.

    PubMed

    Huang, Chuixiu; Seip, Knut Fredrik; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2016-08-31

    Electromembrane extraction (EME) of polar basic drugs from human plasma was investigated for the first time using pure bis(2-ethylhexyl) phosphite (DEHPi) as the supported liquid membrane (SLM). The polar basic drugs metaraminol, benzamidine, sotalol, phenylpropanolamine, ephedrine, and trimethoprim were selected as model analytes, and were extracted from 300 μL of human plasma, through 10 μL of DEHPi as SLM, and into 100 μL of 10 mM formic acid as acceptor solution. The extraction potential across the SLM was 100 V, and extractions were performed for 20 min. After EME, the acceptor solutions were analyzed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In contrast to other SLMs reported for polar basic drugs in the literature, the SLM of DEHPi was highly stable in contact with plasma, and the system-current across the SLM was easily kept below 50 μA. Thus, electrolysis in the sample and acceptor solution was kept at an acceptable level with no detrimental consequences. For the polar model analytes, representing a log P range from -0.40 to 1.32, recoveries in the range 25-91% were obtained from human plasma. Strong hydrogen bonding and dipole interactions were probably responsible for efficient transfer of the model analytes into the SLM, and this is the first report on efficient EME of highly polar analytes without using any ionic carrier in the SLM.

  1. 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.

  2. 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 ...

  3. 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.

  4. An innovative arrangement for in-vial membrane-assisted liquid-liquid microextraction: application to the determination of esters of phthalic acid in alcoholic beverages by gas chromatography-mass spectrometry.

    PubMed

    March, Juan Gabriel; Cerdà, Victor

    2015-05-01

    A new arrangement for membrane-assisted liquid-liquid microextraction is presented. The extracting organic solvent was placed into a chromatographic microvial, compatible with the chromatograph autosampler, whose septum was replaced by a disc of porous hydrophobic membrane. This extraction device was completely immersed into the analytical sample contained in a cylindrical container subjected to rotary and basculant movement. Then, the extraction of analytes took place from the sample to the organic solvent contained in the vial through the membrane. Esters of the phthalic acid have been selected as model analytes to determine the performance characteristics of the extraction system. The limits of detection, limits of quantification and relative standard deviations (%) were in the range 0.1-0.4, 0.3-1 and 4-7, respectively. Esters of phthalic acid have been successfully analysed in alcoholic beverages. The main operational advantages of this arrangement consisted of minimal required handling, minimal risk of cross contamination and its simplicity.

  5. An innovative arrangement for in-vial membrane-assisted liquid-liquid microextraction: application to the determination of esters of phthalic acid in alcoholic beverages by gas chromatography-mass spectrometry.

    PubMed

    March, Juan Gabriel; Cerdà, Victor

    2015-05-01

    A new arrangement for membrane-assisted liquid-liquid microextraction is presented. The extracting organic solvent was placed into a chromatographic microvial, compatible with the chromatograph autosampler, whose septum was replaced by a disc of porous hydrophobic membrane. This extraction device was completely immersed into the analytical sample contained in a cylindrical container subjected to rotary and basculant movement. Then, the extraction of analytes took place from the sample to the organic solvent contained in the vial through the membrane. Esters of the phthalic acid have been selected as model analytes to determine the performance characteristics of the extraction system. The limits of detection, limits of quantification and relative standard deviations (%) were in the range 0.1-0.4, 0.3-1 and 4-7, respectively. Esters of phthalic acid have been successfully analysed in alcoholic beverages. The main operational advantages of this arrangement consisted of minimal required handling, minimal risk of cross contamination and its simplicity. PMID:25876533

  6. 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.

  7. Resonance energy transfer in a model system of membranes: application to gel and liquid crystalline phases.

    PubMed

    Loura, L M; Fedorov, A; Prieto, M

    1996-10-01

    Resonance energy transfer between octadecyl rhodamine B (donor) and 1,1',3,3,3',3'-hexamethylindotricarbocyanine (acceptor) was studied in a model system of membranes (large unilamellar vesicles of dipalmitoylphosphatidylcholine), using both steady-state and time-resolved techniques. In the fluid phase (temperature = 50 degrees C) the decay law and the steady-state theoretical curve for energy transfer in two dimensions are verified. In the gel phase (temperature = 25 degrees C) an apparent reduction of dimensionality is observed, which is explained on the basis of probe segregation to the defect lines (grain boundaries). An estimation of the domain size from the model recovered linear probe concentrations is approximately 1750-2000 lipid molecules. In both phases, the existence of a fractal geometry was ruled out. PMID:8889159

  8. Supported liquid membrane technique applicability for removal of chromium from tannery wastes

    SciTech Connect

    Ashraf Chaudry, M.; Ahmad, S.; Malik, M.T.

    1998-07-01

    The concentration of Cr and other ions have been determined in the effluent liquors of the tanneries around Multan city in Pakistan. The Cr ions concentration varies from 2,500 ppm to 8,000 ppm and sodium ions from 2,100 ppm to 38,000 ppm. Cu has been found in the range of 40 ppm, Ca from 900--1,000 ppm, Mg up to 170 ppm, Fe up to 65 and Zn below 2 ppm level. In the present work it has been shown that the Cr ions present in the tannery wastes can be removed by SLM technique with prior treatment by H{sub 2}O{sub 2} and NaOH. The flux for 4,800 ppm waste samples is in the order of 40 x 10{sup {minus}5} mol m{sup {minus}2} s{sup {minus}1} with permeability of 5 x 10{sup {minus}11} m{sup 2} s{sup {minus}1}. The membrane area required to treat tannery waste coming out at the rate of 100 gallons per day has been calculated to be only 12.6 m{sup 2}. The optimum conditions of treatment are 0.87 mol dm{sup {minus}3} tri-n-octylamine in the membrane and pH 1. If the tannery waste is at 32 C (Multan temperature in summer), the flux is expected to be higher as shown in the present study and the process will be even more efficient. Application of the other systems of Cr removal have also been discussed in brief.

  9. Liquid state DNP for water accessibility measurements on spin-labeled membrane proteins at physiological temperatures.

    PubMed

    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 B(12) 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 ϵ. The ϵ-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.

  10. 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.

  11. Small interfering ribonucleic acid induces liquid-to-ripple phase transformation in a phospholipid membrane

    SciTech Connect

    Choubey, Amit; Nomura, Ken-ichi; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2014-09-15

    Small interfering ribonucleic acid (siRNA) molecules play a pivotal role in silencing gene expression via the RNA interference mechanism. A key limitation to the widespread implementation of siRNA therapeutics is the difficulty of delivering siRNA-based drugs to cells. Here, we examine changes in the structure and dynamics of a dipalmitoylphosphatidylcholine bilayer in the presence of a siRNA molecule and mechanical barriers to siRNA transfection in the bilayer. Our all-atom molecular dynamics simulation shows that siRNA induces a liquid crystalline-to-ripple phase transformation in the bilayer. The ripple phase consists of a major region of non-interdigitated and a minor region of interdigitated lipid molecules with an intervening kink. In the ripple phase, hydrocarbon chains of lipid molecules have large compressive stresses, which present a considerable barrier to siRNA transfection.

  12. Ordered structures in proton conducting membranes from supramolecular liquid crystal polymers.

    PubMed

    Every, Hayley A; Mendes, Eduardo; Picken, Stephen J

    2006-11-30

    Highly sulfonated forms of poly(p-phenylene terephthalamide) (PPTA) have been prepared in three different molecular configurations; sulfonated diamine form (S-PPTA), sulfonated terephthalic acid form (S-invert-PPTA), and the bi-sulfonated form (S2-PPTA). All three polymers are water soluble to a certain degree and films were cast from solution for S-PPTA and S-invert-PPTA. S-PPTA films absorb less water than S-invert-PPTA (under controlled humidity conditions) and consequently, the conductivity for this polymer is also slightly lower. Although the conductivities are comparable to Nafion (of the order of 10(-2) to 10(-1) Scm(-1)), proton mobility is more restricted. X-ray diffraction showed that the rigid molecules are aligned in opposite directions for the two polymer films, being homeotropic in S-PPTA films and planar for S-invert-PPTA. SEM analysis demonstrated layering in the same direction as the alignment of the polymer chains. The variation in the polymer alignment is most likely the result of the differences in the solution properties and the film forming process. It is possible, however, that this alignment could be exploited to enhance proton transport and thus these films are of interest for fuel cell membranes. PMID:17125333

  13. Design and performance of BNR activated sludge systems with flat sheet membranes for solid-liquid separation.

    PubMed

    du Toit, G J G; Ramphao, M C; Parco, V; Wentzel, M C; Ekama, G A

    2007-01-01

    The use of immersed membranes for solid-liquid separation in biological nutrient removal activated sludge (BNRAS) systems was investigated at lab scale. Two laboratory-scale BNR activated sludge systems were run in parallel, one a MBR system and the other a conventional system with secondary settling tanks. Both systems were in 3 reactor anaerobic, anoxic, aerobic UCT configurations. The systems were set up to have, as far as possible, identical design parameters such as reactor mass fractions, recycles and sludge age. Differences were the influent flow and total reactor volumes, and the higher reactor concentrations in the MBR system. The performances of the two systems were extensively monitored and compared to identify and quantify the influence of the membranes on system response. The MBR UCT system exhibited COD, FSA, TKN, TP and TSS removals that were consistently equivalent or superior to the conventional system. Better P removal in the MBR was attributed to lower observed P uptake in the anoxic zone. High nitrate loads to the anoxic reactor appeared to be the determining factor in stimulating P uptake. The MBR UCT system had a greater sludge production than the conventional system. This was partly attributable to the retention of all solids in the MBR reactor. For steady state design this increase is accommodated by increasing the influent unbiodegradable particulate COD fraction. Additionally an attempt was made to determine the Alpha values in the oxygen transfer rate. This paper briefly summarises and compares the results from both systems, and the conclusions that can be drawn from these results.

  14. Electromembrane extraction of polar basic drugs from plasma with pure bis(2-ethylhexyl) phosphite as supported liquid membrane.

    PubMed

    Huang, Chuixiu; Seip, Knut Fredrik; Gjelstad, Astrid; Pedersen-Bjergaard, Stig

    2016-08-31

    Electromembrane extraction (EME) of polar basic drugs from human plasma was investigated for the first time using pure bis(2-ethylhexyl) phosphite (DEHPi) as the supported liquid membrane (SLM). The polar basic drugs metaraminol, benzamidine, sotalol, phenylpropanolamine, ephedrine, and trimethoprim were selected as model analytes, and were extracted from 300 μL of human plasma, through 10 μL of DEHPi as SLM, and into 100 μL of 10 mM formic acid as acceptor solution. The extraction potential across the SLM was 100 V, and extractions were performed for 20 min. After EME, the acceptor solutions were analyzed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In contrast to other SLMs reported for polar basic drugs in the literature, the SLM of DEHPi was highly stable in contact with plasma, and the system-current across the SLM was easily kept below 50 μA. Thus, electrolysis in the sample and acceptor solution was kept at an acceptable level with no detrimental consequences. For the polar model analytes, representing a log P range from -0.40 to 1.32, recoveries in the range 25-91% were obtained from human plasma. Strong hydrogen bonding and dipole interactions were probably responsible for efficient transfer of the model analytes into the SLM, and this is the first report on efficient EME of highly polar analytes without using any ionic carrier in the SLM. PMID:27506347

  15. Selecting a Roof Membrane.

    ERIC Educational Resources Information Center

    Waldron, Larry W.

    1990-01-01

    Offers a brief synopsis of the unique characteristics of the following roof membranes: (1) built-up roofing; (2) elastoplastic membranes; (3) modified bitumen membranes; (4) liquid applied membranes; and (5) metal roofing. A chart compares the characteristics of the raw membranes only. (MLF)

  16. Pore Network Modeling and Synchrotron Imaging of Liquid Water in the Gas Diffusion Layer of Polymer Electrolyte Membrane Fuel Cells

    NASA Astrophysics Data System (ADS)

    Hinebaugh, James Thomas

    Polymer electrolyte membrane (PEM) fuel cells operate at levels of high humidity, leading to condensation throughout the cell components. The porous gas diffusion layer (GDL) must not become over-saturated with liquid water, due to its responsibility in providing diffusion pathways to and from the embedded catalyst sites. Due to the opaque and microscale nature of the GDL, a current challenge of the fuel cell industry is to identify the characteristics that make the GDL more or less robust against flooding. Modeling the system as a pore network is an attractive investigative strategy; however, for flooding simulations to provide meaningful material comparisons, accurate GDL topology and condensation distributions must be provided. The focus of this research is to provide the foundational tools with which to capture both of these requirements. The method of pore network modeling on topologically representative pore networks is demonstrated to describe flooding phenomena within GDL materials. A stochastic modeling algorithm is then developed to create pore spaces with the relevant features of GDL materials. Then, synchrotron based X-ray visualization experiments are developed and conducted to provide insight into condensation conditions. It was found that through-plane porosity distributions have significant effects on the GDL saturation levels. Some GDL manufacturing processes result in high porosity regions which are predicted to become heavily saturated with water if they are positioned between the condensation sites and the exhaust channels. Additionally, it was found that fiber diameter and the volume fraction of binding material applied to the GDL have significant impacts on the GDL heterogeneity and pore size distribution. Representative stochastic models must accurately describe these three material characteristics. In situ, dynamic liquid water behavior was visualized at the Canadian Light source, Inc. synchrotron using imaging and image processing

  17. 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.

  18. Formation of inverse Chladni patterns at microscale by acoustic streaming on a silicon membrane immersed in a liquid

    NASA Astrophysics Data System (ADS)

    Poulain, Cedric; Vuillermet, Gael; Casset, Fabrice

    2015-11-01

    High frequency acoustics (in the MHz range) is known to be very efficient to handle micro particles or living cells in microfluidics by taking advantage of the acoustic radiation force. Here, we will show that low frequency (~ 50kHz) together with use ultra thin silicon plate can give rise to a micro streaming that enables to move particles at will. Indeed, by means of silicon membranes excited in the low ultrasound range, we show that it is possible to form inverse two-dimensional Chladni patterns of micro-beads in liquid. Unlike the well-known effect in a gaseous environment at macroscale, where gravity effects are generally dominant, leading particles towards the nodal regions of displacement, we will show that the micro scale streaming in the vicinity of the plate tends to gather particles in antinodal regions. Moreover, a symmetry breaking effect together with the streaming can trigger a whole rotation of the beads in the fluidic cavity. We demonstrate that it is possible to make the patterns rotate at a well defined angular velocity where beads actually jump from one acoustic trap to another.

  19. 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. PMID:26763094

  20. 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.

  1. Rapid and simple pretreatment of human body fluids using electromembrane extraction across supported liquid membrane for capillary electrophoretic determination of lithium.

    PubMed

    Strieglerová, Lenka; Kubáň, Pavel; Boček, Petr

    2011-05-01

    Electromembrane extraction was used for simultaneous sample cleanup and preconcentration of lithium from untreated human body fluids. The sample of a body fluid was diluted 100 times with 0.5 mM Tris solution and lithium was extracted by electromigration through a supported liquid membrane composed of 1-octanol into 100 mM acetic acid acceptor solution. Matrix compounds, such as proteins, red blood cells, and other high-molecular-weight compounds were efficiently retained on the supported liquid membrane. The liquid membrane was anchored in pores of a short segment of a polypropylene hollow fiber, which represented a low cost, single use, disposable extraction unit and was discarded after each use. Acceptor solutions were analyzed using capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4) D) and baseline separation of lithium was achieved in a background electrolyte solution consisting of 18 mM L-histidine and 40 mM acetic acid at pH 4.6. Repeatability of the electromembrane extraction-CE-C(4) D method was evaluated for the determination of lithium in standard solutions and real samples and was better than 0.6 and 8.2% for migration times and peak areas, respectively. The concentration limit of detection of 9 nM was achieved. The developed method was applied to the determination of lithium in urine, blood serum, blood plasma, and whole blood at both endogenous and therapeutic concentration levels.

  2. 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.

  3. 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

    2014-07-01

    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.

  4. Membrane assisted solvent extraction coupled with liquid chromatography tandem mass spectrometry applied to the analysis of alkylphenols in water samples.

    PubMed

    Salgueiro-González, N; Turnes-Carou, I; Muniategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

    2013-03-15

    This work describes the development and validation of a novel, simple, sensitive and environmental friendly analytical method for the determination of alkylphenols in different types of water samples. The methodology was based on a membrane assisted solvent extraction of only 15 mL of water sample with 500 μL of hexane in combination with liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode (LC-ESI-MS/MS). Acquisition was performed in the multiple reaction monitoring (MRM) mode recording two transitions for the identification of the target compounds. Quantitation is based on the use of deuterated labelled standards as surrogate standards. The figures of merit were satisfactory in all cases: absolute recoveries were close to 50% for most investigated compounds and relative recoveries varied between 81 and 108%. Repeatability and intermediate precision were <20% for all compounds. Uncertainty assessment of measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) were lower than 0.04 μg L(-1) in all cases, which allow the achievement of the limits established by the Directive 2008/105/EC for surface and seawater samples and by the new proposal COM (2011) 876 final. The feasibility of the proposed method was demonstrated analyzing seawater, surface water and drinking water samples from different areas of A Coruña (Northwest of Spain). The analyses evidenced the presence of nonylphenol in seawater (MQL-0.13 μg L(-1)) and surface water samples (0.12-0.19 μg L(-1)). The highest concentration was observed in drinking water (0.25 μg L(-1)).

  5. 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.

  6. A membrane-free lithium/polysulfide semi-liquid battery for large-scale energy storage

    SciTech Connect

    Yang, Yuan; Zheng, Guangyuan; Cui, Yi

    2013-01-01

    Large-scale energy storage represents a key challenge for renewable energy and new systems with low cost, high energy density and long cycle life are desired. In this article, we develop a new lithium/polysulfide (Li/PS) semi-liquid battery for large-scale energy storage, with lithium polysulfide (Li{sub 2}S{sub 8}) in ether solvent as a catholyte and metallic lithium as an anode. Unlike previous work on Li/S batteries with discharge products such as solid state Li{sub 2}S{sub 2} and Li{sub 2}S, the catholyte is designed to cycle only in the range between sulfur and Li{sub 2}S{sub 4}. Consequently all detrimental effects due to the formation and volume expansion of solid Li{sub 2}S{sub 2}/Li{sub 2}S are avoided. This novel strategy results in excellent cycle life and compatibility with flow battery design. The proof-of-concept Li/PS battery could reach a high energy density of 170 W h kg{sup -1} and 190 W h L{sup -1} for large scale storage at the solubility limit, while keeping the advantages of hybrid flow batteries. We demonstrated that, with a 5 M Li{sub 2}S{sub 8} catholyte, energy densities of 97 W h kg{sup -1} and 108 W h L{sup -1} can be achieved. As the lithium surface is well passivated by LiNO{sub 3} additive in ether solvent, internal shuttle effect is largely eliminated and thus excellent performance over 2000 cycles is achieved with a constant capacity of 200 mA h g{sup -1}. This new system can operate without the expensive ion-selective membrane, and it is attractive for large-scale energy storage.

  7. 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

    2014-01-01

    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

  8. Development of a new highly conductive and thermomechanically stable complex membrane based on sulfonated polyimide/ionic liquid for high temperature anhydrous fuel cells

    NASA Astrophysics Data System (ADS)

    Deligöz, Hüseyin; Yılmazoğlu, Mesut

    The paper deals with the synthesis and characterization of a new type of acid doped highly conductive complex membrane based on sulfonated polyimide (sPI) and ionic liquid (IL) for high temperature anhydrous fuel cells. For this purpose, 2,4-diaminobenzene sulfonic acid (2,4-DABSA) is reacted with benzophenontetracarboxylic dianhydride (BTDA) to yield sulfonated poly(amic acid) (sPAA) intermediate. Subsequently, IL is added into sPAA to form an interaction between sulfonic acid and imidazolium group of IL followed by acid doping. The ionic conductivity of acid doped sPI/IL complex polymer membrane is higher than that of IL containing composite membranes reported in the literature (5.59 × 10 -2 S cm -1 at 180 °C). Furthermore, dynamic mechanical analysis (DMA) results of acid doped sPI/IL complex membrane show that the mechanical strength of the complex product is slightly changed until 350 °C due to the formation of ionic interactions between sulfonic acid groups of sPI and imidazolium groups of IL. Consequently, the ionic interaction not only provides high ionic conductivity with excellent thermomechanical properties (the storage module of 0.91 GPa at 300 °C) but also results in a positive effect in long term conductivity stability by blocking IL migration through the membrane.

  9. 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

  10. 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.

  11. 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.; Skrabalak, Sara E.

    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.

  12. 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.

  13. 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.

  14. Large-area graphene-based nanofiltration membranes by shear alignment of discotic nematic liquid crystals of graphene oxide.

    PubMed

    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 cm(2)) 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. 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.

  16. A new selective liquid membrane extraction method for the determination of basic herbicides in agro-processed fruit juices and Ethiopian honey wine (Tej) samples.

    PubMed

    Megersa, Negussie; Kassahun, Samuel

    2012-01-01

    Supported liquid membrane (SLM) extraction was optimised for trace extraction and enrichment of selected triazine herbicides from a variety of agro-processed fruit juices and Ethiopian honey wine (Tej) samples. In the extraction process, a 1:1 mixture of n-undecane and di-n-hexylether was immobilised in a thin porous PTFE membrane that forms a barrier between two aqueous phases (the donor and acceptor phases) in a flow system. The extracts constitute the selectively enriched analytes collected from the acceptor phase and were analysed by transferring to a HPLC-UV system using a diode array detector at 235 nm. High enrichment factors were obtained with very good repeatability of results, and the detection limit was lower than 3.00 µg l⁻¹ for ametryn in apple juice. The optimised method showed very good linearity of over 50-500 µg l⁻¹ with a correlation coefficient of >0.990 or better for triplicate analysis. All chromatograms gave well resolved peaks with no interfering peaks at the retention times of the selected triazines, showing high selectivity of the SLM extraction method in combination with HPLC-UV for the selected matrices. The optimised method can be used as an alternative solventless extraction method for microgram-level extraction of other triazine herbicides and a variety of pesticides from liquid and semi-liquid environmental, biological and food matrices. PMID:22324905

  17. 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. PMID:27116588

  18. Partitioning of actinides from high level waste of PUREX origin using octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO)-based supported liquid membrane

    SciTech Connect

    Ramanujam, A.; Dhami, P.S.; Gopalakrishnan, V.; Dudwadkar, N.L.; Chitnis, R.R.; Mathur, J.N.

    1999-06-01

    The present studies deal with the application of the supported liquid membrane (SLM) technique for partitioning of actinides from high level waste of PUREX origin. The process uses a solution of octylphenyl-N,N{prime}-diisobutylcarbamoylmethyl phosphine oxide (CMPO) in n-dodecane as a carrier with a polytetrafluoroethylene support and a mixture of citric acid, formic acid, and hydrazine hydrate as the receiving phase. The studies involve the investigation of such parameters as carrier concentration in SLM, acidity of the feed, and the feed composition. The studies indicated good transport of actinides like neptunium, americium, and plutonium across the membrane from nitric acid medium. A high concentration of uranium in the feed retards the transport of americium, suggesting the need for prior removal of uranium from the waste. The separation of actinides from uranium-lean simulated samples as well as actual high level waste has been found to be feasible using the above technique.

  19. Passive extraction and clean-up of phenoxy acid herbicides in samples from a groundwater plume using hollow fiber supported liquid membranes.

    PubMed

    Liu, Jing-Fu; Toräng, Lars; Mayer, Philipp; Jönsson, Jan Ake

    2007-08-10

    Hollow fiber supported liquid membranes were applied for the passive extraction of phenoxy acid herbicides from water samples. Polypropylene hollow fiber membranes (240 microm i.d., 30 microm wall thickness, 0.05 microm pore size, 30 cm length) were impregnated with 2.0% tri-n-octylphosphine oxide (TOPO) in di-n-hexyl ether in the pores of the fiber wall to form a liquid membrane. They were then filled with basic solution in the lumen as acceptor and finally placed into the sample (donor). Complete extraction of phenoxy acid herbicides including 2,4-D, MCPA, dichlorprop, and mecoprop from an acidified sample (4 mL, adjusted to pH 1.5 with HCl) into basic acceptor (10 microL of 0.2M NaOH) was achieved after 4 h of shaking (100 rpm) resulting in an enrichment factor of 400 times. The acceptor was then neutralized by addition of HCl and injected into a HPLC system for the determination of the phenoxy acid herbicides. Environmentally relevant salinity (0-3.5% NaCl) and dissolved organic matter (0-25 mg/L of dissolved organic carbon) had no significant effect on the extraction. The method provided extraction efficiencies of more than 91%, detection limits of 0.3-0.6 microg/L, and combined extraction and clean up in one single step. This procedure was applied to determine aqueous concentrations of phenoxy acid herbicides in groundwater samples collected from an old dumping site (Cheminova, Denmark) with detected concentrations up to 5800 microg/L. Although the samples were very dirty with large amounts of suspended particles, non-aqueous phase liquids (NAPLs) and dissolved organic matters, good spike recoveries (80-126%) were obtained for 10 of the 11 samples.

  20. Supported liquid membrane based removal of lead(II) and cadmium(II) from mixed feed: Conversion to solid waste by precipitation.

    PubMed

    Bhatluri, Kamal Kumar; Manna, Mriganka Sekhar; Ghoshal, Aloke Kumar; Saha, Prabirkumar

    2015-12-15

    Simultaneous removal of two heavy metals, lead(II) and cadmium(II), from mixed feed using supported liquid membrane (SLM) based technique is investigated in this work. The carrier-solvent combination of "sodium salt of Di-2-ethylhexylphosphoric acid (D2EHPA) (4% w/w) in environmentally benign coconut oil" was immobilized into the pores of solid polymeric polyvinylidene fluoride (PVDF) support. Sodium carbonate (Na2CO3) was used as the stripping agent. Carbonate salts of lead(II) and cadmium(II) were formed in the stripping side interface and they were insoluble in water leading to precipitation inside the stripping solution. The transportation of solute is positively affected due to the precipitation. Lead(II) removal was found to be preferential due to its favorable electronic configuration. The conversion of the liquid waste to the solid one was added advantage for the final removal of hazardous heavy metals. PMID:26252994

  1. 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.

  2. Membrane damage and viability loss of Escherichia coli K-12 and Salmonella enteritidis in liquid egg by thermal death time disk treatment.

    PubMed

    Ukuku, Dike O; Jin, Tony; Zhang, Howard

    2008-10-01

    Bacterial injury, including leakage of intracellular substance and viability loss, of Escherichia coli K-12 (ATCC 23716) and Salmonella Enteritidis (ATCC 13076) inoculated in liquid egg white and liquid whole egg was determined by thermal death time disk. E. coli K-12 and Salmonella Enteritidis were inoculated in liquid egg white and liquid whole egg to a final count of 7.8 log CFU/ml and were thermally treated with thermal death time disks at room temperature (23"C), 54, 56, 58, and 60 degrees C from 0 to 240 s. Sublethal injury, leakage of intracellular substances, and viability loss of E. coli K-12 and Salmonella Enteritidis was investigated by plating 0.1 ml on selective trypticase soy agar containing 3% NaCl, 5% NaCl, sorbitol MacConky agar, and xylose lysine sodium tetradecylsulfate and nonselective trypticase soy agar. No significant (P > 0.05) differences on percent injury or viability loss for E. coli K-12 and Salmonella populations were determined in all samples treated at 23 degrees C. Sublethal injury occurred in E. coli and Salmonella populations at 54 degrees C or above for 120 s. Viability losses for both bacteria averaged 5 log at 54 degrees C or above for 180 s, and the surviving populations were below detection (<10 CFU/ml). Thermal treatment at 40 degrees C and above led to membrane damage, leakage, and accumulation of intracellular ATP from 2 to 2.5 log fg/ml and UV-absorbing substances of 0.1 to 0.39 in the treated samples. These results indicate similar thermal injury/damage on both E. coli and Salmonella membranes as determined by the amount of inactivation, viability loss, and leakage of intracellular substances of bacteria.

  3. 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

  4. Ion-transfer voltammetric determination of the beta-blocker propranolol in a physiological matrix at silicon membrane-based liquid|liquid microinterface arrays.

    PubMed

    Collins, Courtney J; Arrigan, Damien W M

    2009-03-15

    In this work, the ion-transfer voltammetric detection of the protonated beta-blocker propranolol in artificial saliva is presented. Cyclic voltammetry, differential pulse voltammetry, and differential pulse stripping voltammetry (DPSV) were employed in the detection of the cationic drug based on ion-transfer voltammetry across arrays of microinterfaces between artificial saliva and an organogel phase. It was found that the artificial saliva matrix decreased the available potential window for ion-transfer voltammetry at this liquid|liquid interface but transfer of protonated propranolol was still achieved. The DPSV method employed a preconditioning step as well as a preconcentration step followed by analytical signal generation based on the back-transfer of the drug across the array of microinterfaces. The DPSV peak current response was linear with drug concentration in the artificial saliva matrix over the concentration range of 0.05-1 microM (i(p) = -8.13 (nA microM(-1))(concentration) + 0.07 (nA), R = 0.9929, n = 7), and the calculated detection limit (3s(b)) was 0.02 microM. These results demonstrate that DPSV at arrays of liquid|liquid microinterfaces is a viable analytical approach for pharmaceutical determinations in biomimetic matrixes.

  5. 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

  6. Structure-relaxation interplay of a new nanostructured membrane based on tetraethylammonium trifluoromethanesulfonate ionic liquid and neutralized nafion 117 for high-temperature fuel cells.

    PubMed

    Di Noto, Vito; Negro, Enrico; Sanchez, Jean-Yves; Iojoiu, Christina

    2010-02-24

    In this report, the electrical performance at T > 100 degrees C and low relative humidity of proton-conducting Nafion-based membranes was improved by preparing new materials based on Nafion 117 (N117) neutralized with triethylammonium (TEA(+)) and doped with the ionic liquid (IL) trifluoromethanesulfonate of triethylammonium (TEA-TF). In particular, a new two-step protocol for the preparation of [N117(x-)(TEA(+))(x)/(TEA-TF)(y)] is proposed. [N117(x-)(TEA(+))(x)/(TEA-TF)(y)] membrane is composed of ca. 30 wt % of TEA-TF. The structure of the different nanophases composing the materials and their interactions were investigated by FT-IR ATR and micro-Raman spectroscopy. The thermal stability, water uptake, and mechanical properties of the membranes were studied by thermogravimetric analysis and dynamic mechanical analysis measurements. With respect to pristine N117, the thermal and mechanical properties of the proposed materials were improved. The electric response of [N117(x-)(TEA(+))(x)/(TEA-TF)(y)] was studied by broad band dielectric spectroscopy in the frequency range from 10(-2) Hz to 10 MHz and for temperatures between 5 and 155 degrees C. In comparison to the N117 reference, the following was observed: (a) the stability range of conductivity (SRC) of the [N117(x-)(TEA(+))(x)] membrane increases up to 155 degrees C, while its sigma(DC) at T = 100 degrees C is lowered by ca. 2 orders of magnitude; (b) the SRC of [N117(x-)(TEA(+))(x)/(TEA-TF)(y)] is similar to that of [N117(x-)(TEA(+))(x)], while the sigma(DC) at 145 degrees C decreases in the order 7.3 x 10(-3) > 6.1 x 10(-3) > 9.7 x 10(-4) S x cm(-1) for [N117(x-)(TEA(+))(x)/(TEA-TF)(y)], N117, and [N117(x-)(TEA(+))(x)] membranes, respectively. In conclusion, the lower water uptake, the improved thermal and mechanical stability, and the good conductivity make [N117(x-)(TEA(+))(x)/(TEA-TF)(y)] a promising membrane to improve for application in proton exchange membrane fuel cells operating under anhydrous

  7. 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.

  8. 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.

  9. Impact of micro-porous layer on liquid water distribution at the catalyst layer interface and cell performance in a polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Tabe, Yutaka; Aoyama, Yusuke; Kadowaki, Kazumasa; Suzuki, Kengo; Chikahisa, Takemi

    2015-08-01

    In polymer electrolyte membrane fuel cells, a gas diffusion layer (GDL) with a micro-porous layer (MPL) gives better anti-flooding performance than GDLs without an MPL. To investigate the function and mechanism of the MPL to suppress water flooding, the liquid water distribution at the cathode catalyst layer (CL) surface are observed by a freezing method; in the method liquid water is immobilized in ice form by rapid freezing, followed by disassembling the cell for observations. The ice covered area is quantified by image processing and cells with and without an MPL are compared. The results show that the MPL suppresses water accumulation at the interface due to smaller pore size and finer contact with the CL, and this results in less water flooding. Investigation of ice formed after -10 °C cold start shutdowns and the temporary performance deterioration at ordinary temperatures also indicates a significant influence of the liquid water accumulating at the interface. The importance of the fine contact between CL and MPL, the relative absence of gaps, is demonstrated by a gas diffusion electrode (GDE) which is directly coated with catalyst ink on the surface of the MPL achieving finer contact of the layers.

  10. 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.

  11. 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.

  12. 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.

  13. Combining molecular dynamics simulation and transition state theory to evaluate solid-liquid interfacial friction in carbon nanotube membranes

    NASA Astrophysics Data System (ADS)

    Babu, Jeetu S.; Sathian, Sarith P.

    2012-05-01

    A molecular dynamics (MD) methodology based on Eyring theory of reaction rates is proposed for investigating solid-liquid interfacial properties crucial to the development of many nanotechnology applications. The method involves the calculation of activation energy required for the flow process directly from the MD trajectory information. We have applied this methodology to study the behavior of water in hydrophobic confinement in carbon nanotubes (CNTs) and also between graphene sheets. In the case of confined water molecules in CNTs and between graphene sheets the degree of confinement and curvature effects were found to have more influence on the solid-liquid interfacial friction, with almost negligible friction below a certain characteristic dimension in both the cases. This behavior of confined and unconfined water molecules is explained on the basis of molecular interactions and subsequent changes in the activation energy. Analysis based on this method also revealed that a finite amount of friction does exist at the channel entry and exit region. This could limit the flow of liquid molecules through the nanochannels and hence needs to be taken into account in the design of nanofluidic devices.

  14. 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.

  15. Novel macrocyclic carriers for proton-coupled liquid membrane transport. Progress report, December 1, 1991--November 30, 1992

    SciTech Connect

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

    1992-07-01

    A number of new macrocyclic ligands was prepared for transport studies. The cryptands were prpepared (18-40% yield) by a new metal carbonate-catalyzed one-step method from 1 mole oligoethyleneoxy diamine and 2 moles diahlide derivative of oligoethylene glycol. Bis-crown ethers were also isolated in 17-30% yields. Cage compounds were also prepared; they interact with various metal ions and protons. Back extraction and dual module hollow fiber membrane separation experiments were used to study the cation selectivity of new ligands, including crown thioethers. An isothermal flow calorimeter is being constructed for studies of macrocycle-cation reactions. 3 figs, 2 tabs.

  16. Effects of hypothermic liquid storage and cryopreservation on basal and induced plasma membrane phospholipid disorder and acrosome exocytosis in boar spermatozoa.

    PubMed

    Guthrie, H D; Welch, G R

    2005-01-01

    Flow cytometry was utilised to determine whether short-term (Day 1) or long-term hypothermic liquid storage (Day 5), or cryopreservation of boar spermatozoa (1) caused changes in plasma membrane phospholipid disorder (MPLD) and acrosome exocytosis (AE), indicative of an advanced stage of capacitation or acrosome status, and (2) facilitated or inhibited the induction of capacitation and the acrosome reaction. Merocyanine with Yo-Pro-1 and peanut agglutinin-fluorescein isothiocyanate with propidium iodide were used to identify MPLD and AE, respectively, in viable spermatozoa. The incidence of basal sperm MPLD and AE in fresh semen was very low (1.1 and 2.2%, respectively) and was increased (P < 0.05) only a small amount in Day 5 and cryopreserved semen (3-8%). Compared to no bicarbonate, incubation with bicarbonate increased MPLD, but the response was greatest (P < 0.05) in fresh sperm (52.3%) compared with Day 1 (36.6%), Day 5 (13.9%) and cryopreserved sperm (13.6%). Incubation with calcium ionophore A23187 increased AE in spermatozoa, but the response was less (P < 0.05) for fresh (34%) and cryopreserved (27%) semen than for Day 1 (45%) and Day 5 (57%) semen. In summary, hypothermic liquid storage and cryopreservation of boar spermatozoa did not advance capacitation or acrosome status in viable spermatozoa, but did alter their responses to induction of capacitation and the acrosome reaction. PMID:15899159

  17. Effects of liquid chromatography mobile phases and buffer salts on phosphorus inductively coupled plasma atomic emission and mass spectrometries utilizing ultrasonic nebulization and membrane desolvation.

    PubMed

    Carr, John E; Kwok, Kaho; Webster, Gregory K; Carnahan, Jon W

    2006-01-23

    Atomic spectrometry, specifically inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) show promise for heteroatom-based detection of pharmaceutical compounds. The combination of ultrasonic nebulization (USN) with membrane desolvation (MD) greatly enhances detection limits with these approaches. Because pharmaceutical analyses often incorporate liquid chromatography, the study herein was performed to examine the effects of solvent composition on the analytical behaviors of these approaches. The target analyte was phosphorus, introduced as phosphomycin. AES response was examined at the 253.7 nm atom line and mass 31 ions were monitored for the MS experiments. With pure aqueous solutions, detection limits of 5 ppb (0.5 ng in 0.1 mL injection volumes) were obtained with ICP-MS. The ICP-AES detection limit was 150 ppb. Solvent compositions were varied from 0 to 80% organic (acetonitrile and methanol) with nine buffers at concentrations typically used in liquid chromatography. In general, solvents and buffers had statistically significant, albeit small, effects on ICP-AES sensitivities. A few exceptions occurred in cases where typical liquid chromatography buffer concentrations produced higher mass loadings on the plasma. Indications are that isocratic separations can be reliably performed. Within reasonable accuracy tolerances, it appears that gradient chromatography can be performed without the need for signal response normalization. Organic solvent and buffer effects were more significant with ICP-MS. Sensitivities varied significantly with different buffers and organic solvent content. In these cases, gradient chromatography will require careful analytical calibration as solvent and buffer content is varied. However, for most buffer and solvent combinations, signal and detection limits are only moderately affected. Isocratic separations and detection are feasible.

  18. 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

  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. Structural characterization of the voltage sensor domain and voltage-gated K+- channel proteins vectorially-oriented within a single bilayer membrane at the solid/vapor and solid/liquid interfaces via neutron interferometry

    PubMed Central

    Gupta, S.; Dura, J.A.; Freites, J.A.; Tobias, D.J.; Blasie, J. K.

    2012-01-01

    The voltage-sensor domain (VSD) is a modular 4-helix bundle component that confers voltage sensitivity to voltage-gated cation channels in biological membranes. Despite extensive biophysical studies and the recent availability of x-ray crystal structures for a few voltage-gated potassium (Kv-) channels and a voltage-gate sodium (Nav-) channel, a complete understanding of the cooperative mechanism of electromechanical coupling, interconverting the closed-to-open states (i.e. non-conducting to cation conducting) remains undetermined. Moreover, the function of these domains is highly dependent on the physical-chemical properties of the surrounding lipid membrane environment. The basis for this work was provided by a recent structural study of the VSD from a prokaryotic Kv-channel vectorially-oriented within a single phospholipid (POPC; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) membrane investigated by x-ray interferometry at the solid/moist He (or solid/vapor) and solid/liquid interfaces thus achieving partial to full hydration, respectively (Gupta et. al. Phys. Rev E. 2011, 84). Here, we utilize neutron interferometry to characterize this system in substantially greater structural detail at the sub-molecular level, due to its inherent advantages arising from solvent contrast variation coupled with the deuteration of selected sub-molecular membrane components, especially important for the membrane at the solid/liquid interface. We demonstrate the unique vectorial orientation of the VSD and the retention of its molecular conformation manifest in the asymmetric profile structure of the protein within the profile structure of this single bilayer membrane system. We definitively characterize the asymmetric phospholipid bilayer solvating the lateral surfaces of the VSD protein within the membrane. The profile structures of both the VSD protein and phospholipid bilayer depend upon the hydration state of the membrane. We also determine the distribution of water and

  2. 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.

  3. Rapid determination of sulfonamide residues in pork by surface-modified hydrophilic electrospun nanofibrous membrane solid-phase extraction combined with ultra-performance liquid chromatography.

    PubMed

    Chen, Rong; Yang, Yingying; Qu, Bin; Li, Yue; Lu, Yong; Tian, Lingling; Shen, Weiyang; Ramakrishna, Seeram

    2016-08-01

    This study aimed to rapidly determine 13 representative sulfonamide (SA) residues in pork by using a surface-modified hydrophilic polystyrene sulfonic acid (PSSA) electrospun nanofibrous membrane as the solid-phase extraction (SPE) pretreatment sorbent, followed by ultra-performance liquid chromatography (UPLC) analysis. The highly hydrophilic nature of PSSA nanofibrous membrane created by vacuum plasma treatment was characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), water contact angle, and X-ray photoelectron spectroscopy (XPS) measurements. In the pretreatment procedures, 13 SA standards, which were spiked in the fatty pork samples, were extracted, enriched, and purified by the SPE procedure based on the principle of ion exchange with the sulfonic groups on the PSSA chains. Under the optimized conditions, the calibration curves of 13 SA compounds showed good linearities with correlation coefficients (r) of more than 0.99 in the range of 50.0-200 μg kg(-1). The mean recoveries of 13 SAs at the spiked concentrations of 50, 100, and 200 μg kg(-1) were in the range of 70.3-92.5 % with average RSDs (n = 6) of less than 15 % (except for sulfacetamide, 56.9-61.6 %). Compared with other pretreatment methods reported previously, less organic solvent (especially without degreasing the extract with n-hexane) was used in this time-saving SPE procedure, which avoids the possibility of emulsification and therefore enhances the recoveries. The developed and validated analysis method was sensitive, accurate, rapid, convenient, environmentally friendly, and was successfully applied for the detection of 13 SA residues in commercially available pork samples. PMID:27235160

  4. Functionalized nanoparticles based solid-phase membrane micro-tip extraction and high-performance liquid chromatography analyses of vitamin B complex in human plasma.

    PubMed

    Ali, Imran; Kulsum, Umma; Al-Othman, Zeid A; Alwarthan, Abdulrahman; Saleem, Kishwar

    2016-07-01

    Iron nanoparticles were prepared by a green method following functionalization using 1-butyl-3-methylimidazolium bromide. 1-Butyl-3-methylimidazole iron nanoparticles were characterized using FTIR spectroscopy, energy dispersive X-ray fluorescence, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The nanoparticles were used in solid-phase membrane micro-tip extraction to separate vitamin B complex from plasma before high-performance liquid chromatography. The optimum conditions obtained were sorbent (15 mg), agitation time (30 min), pH (9.0), desorbing solvent [water (5 mL) + methanol (5 mL) + sodium hydroxide (0.1 N) + acetic acid (d = 1.05 kg/L, pH 5.5), desorbing volume (10 mL) and desorption time (30 min). The percentage recoveries of all the eight vitamin B complex were from 60 to 83%. A high-performance liquid chromatography method was developed using a PhE column (250 × 4.6 mm, 5.0 μm) and water/acetonitrile (95:5, v/v; pH 4.0 with 0.1% formic acid) mobile phase. The flow rate was 1.0 mL/min with detection at 270 and 210 nm. The values of the capacity, separation and resolution factor were 0.57-39.47, 1.12-6.00 and 1.84-26.26, respectively. The developed sample preparation and chromatographic methods were fast, selective, inexpensive, economic and reproducible. The developed method can be applied for analyzing these drugs in biological and environmental matrices.

  5. 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.

  6. 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.

  7. Porous membrane-protected molecularly imprinted polymer micro-solid-phase extraction for analysis of urinary cocaine and its metabolites using liquid chromatography - Tandem mass spectrometry.

    PubMed

    Sánchez-González, Juan; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2015-10-22

    Porous membrane-protected micro-solid phase extraction (μ-SPE) using a molecularly imprinted polymer (MIP) as an adsorbent has been proposed as an integrated extraction-cleanup procedure for isolating cocaine (COC) and its metabolites [benzoylecgonine (BZE), ecgonine methyl ester (EME), and cocaethylene (CE)] from human urine. MIP beads have been synthesized using COC as a template molecule, ethylene dimethacrylate (EDMA) as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. High performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) has been used for quantifying the analytes after MIP-μ-SPE. Variables such as urine pH, adsorption temperature and time, mechanical (orbital-horizontal) stirring; and composition of the eluting solution and eluting time, were evaluated. The proposed method was shown to be precise and accurate [relative standard deviations (RSDs) of intra- and inter-day tests ranging from 3 to 8% and from 2 to 10%, respectively]; and analytical recoveries in the range of 89-100%). In addition, excellent accuracy was also verified after analyzing a FDT +25% control material for BZE. The detection limits were in the range of 0.16-1.7 ng L(-1), low enough for confirmative conclusions regarding cocaine abuse. The method was finally applied for screening/quantifying cocaine and metabolites in urine samples from poly-drug abusers. PMID:26526910

  8. Selective transport of copper(I, II), cadmium(II), and zinc(II) ions through a supported liquid membrane containing bathocuproine, neocuproine, or bathophenanthroline

    SciTech Connect

    Saito, Takashi )

    1994-06-01

    Some selective transport systems for heavy metallic ions through a supported liquid membrane (SLM) containing a 2,2[prime]-dipyridyl derivative ligand, 4,7-diphenyl-2,9-dimethyl-1, 10-phenanthroline (bathocuproine), 2,9-dimethyl-1,10-phenanthroline (neocuproine), or 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline), were investigated. The transport of copper(I, II), cadmium(II), zinc(II), lead(II), and cobalt(II) ions was accomplished with a halogen ion such as chloride, bromide, or iodide ion as a pairing ion species for any SLM. The ranking of the permeability of the metallic ions was Cu[sup +,2+], Zn[sup 2+], Cd[sup 2+] [much gt] Pb[sup 2+], Co[sup 2+]. When the oxidation-reduction potential gradient was used as a driving force for metallic ions, the transport of Cu[sup +] ions was higher than those of Cd[sup 2+] and Zn[sup 2+] ions for any SLM containing bathocuproine, neocuproine, or bathophenanthroline. On the other hand, in the transport system which used the concentration gradient of pairing ion species, the permeability of the Cu[sup 2+] ion decreased whereas that of the Cd[sup 2+] ion increased. Moreover, it was found that the different selectivity for the transport of metallic ions is produced by using various pairing ion species. 18 refs., 9 figs.

  9. Modelling of the vapour-liquid equilibrium of water and the in situ concentration of H3PO4 in a high temperature proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Kazdal, Timur J.; Lang, Sebastian; Kühl, Frank; Hampe, Manfred J.

    2014-03-01

    The fuel cell technology is a key element for the hydrogen energy economy and therefore crucial for sustainable development. High temperature proton exchange membrane (HT-PEM) fuel cells (FC) can be operated with reformate gas and thus represent an important bridging technology for the energy transition to a renewable energy based system. HT-PEM FCs based on phosphoric acid (PA) are still subject to intense research, investigating the electrolyte behaviour. By enhancing state of the art 2D FEM simulations of FCs with the vapour liquid equilibrium of water-phosphoric acid and evaporation kinetics, a model was created in which the local concentration of PA can be calculated. Knowledge of the concentration field yields the basis for calculating the locally varying ionic conductivity and other physical properties. By describing the volume expansion behaviour of PA it was possible to predict the catalyst particle deactivation due to the swelling of PA. The in situ concentration predicted by the simulation ranges from 96 to 111 wt%. The model was validated using measured data of a single cell design for different temperatures and pressures. By varying the PA content flooding of the simulated fuel cell could be observed and was linked to humidification effects.

  10. Porous membrane-protected molecularly imprinted polymer micro-solid-phase extraction for analysis of urinary cocaine and its metabolites using liquid chromatography - Tandem mass spectrometry.

    PubMed

    Sánchez-González, Juan; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2015-10-22

    Porous membrane-protected micro-solid phase extraction (μ-SPE) using a molecularly imprinted polymer (MIP) as an adsorbent has been proposed as an integrated extraction-cleanup procedure for isolating cocaine (COC) and its metabolites [benzoylecgonine (BZE), ecgonine methyl ester (EME), and cocaethylene (CE)] from human urine. MIP beads have been synthesized using COC as a template molecule, ethylene dimethacrylate (EDMA) as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. High performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) has been used for quantifying the analytes after MIP-μ-SPE. Variables such as urine pH, adsorption temperature and time, mechanical (orbital-horizontal) stirring; and composition of the eluting solution and eluting time, were evaluated. The proposed method was shown to be precise and accurate [relative standard deviations (RSDs) of intra- and inter-day tests ranging from 3 to 8% and from 2 to 10%, respectively]; and analytical recoveries in the range of 89-100%). In addition, excellent accuracy was also verified after analyzing a FDT +25% control material for BZE. The detection limits were in the range of 0.16-1.7 ng L(-1), low enough for confirmative conclusions regarding cocaine abuse. The method was finally applied for screening/quantifying cocaine and metabolites in urine samples from poly-drug abusers.

  11. 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.

  12. Efficient transport of Am(III) from nitric acid medium using a new conformationally constrained (N,N,N',N'-tetra-2-ethylhexyl)7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide across a supported liquid membrane.

    PubMed

    Sharma, S; Panja, S; Ghosh, S K; Dhami, P S; Gandhi, P M

    2016-03-15

    Am(III) is one of the most hazardous radionuclide present in nuclear fuel cycle. A new conformationally constrained diamide, (N,N,N',N'-tetra-2-ethylhexyl)7-oxabicyclo[2.2.1]heptane-2,3-dicarboxamide (OBDA) was studied for Am(III) transport from HNO3 medium across a Supported Liquid Membrane. Transport rate was observed to be significantly fast with ∼95% transport of Am(III) within 1h using 0.1M OBDA in the presence of 15% isodecyl alcohol (IDA)/n-dodecane as carrier. The mechanism of transport was investigated by studying various parameters like feed HNO3/NaNO3 concentration, OBDA concentration in the membrane, membrane pore size, membrane thickness etc. From these studies, the mechanism of transport was found to be diffusion controlled with diffusion co-efficient value of 5.1×10(-6)cm(2)/s. The membrane was found to be highly selective for tri- and tetra-valent actinides, and trivalent lanthanides. OBDA based membrane was found to be stable for at least for ten consecutive cycles of operation. PMID:26685064

  13. Liquid/liquid heat exchanger

    NASA Technical Reports Server (NTRS)

    Miller, C. G.

    1980-01-01

    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  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. PMID:27207577

  19. 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.

  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. Organic fluid permeation through fluoropolymer membranes

    SciTech Connect

    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.

  2. 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.

  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. Evaluation of performance and microbial ecology of sequencing batch reactor and membrane bioreactor treating thin-film transistor liquid crystal display wastewater.

    PubMed

    Wu, Y J; Whang, L M; Huang, S J; Yang, Y F; Lei, C N; Cheng, S S

    2008-01-01

    In Taiwan, a substantial amount of thin-film transistor liquid crystal display (TFT-LCD) wastewater is produced daily due to an increasing production of the opto-electronic industry in recent years. The main components of TFT-LCD wastewater include dimethyl sulphoxide (DMSO), monoethanolamine (MEA), and tetra-methyl ammonium hydroxide (TMAH), which are recognized as non-or slow-biodegradable organic compounds and limited information is available regarding their biological treatablility. This study was conducted to evaluate the long-term performance of two bioreactors, anaerobic-aerobic (A/O) sequencing batch reactor (SBR) and aerobic membrane bioreactor (MBR), treating synthetic TFT-LCD wastewater containing DMSO, MEA, and TMAH with different loadings. For the A/O SBR, the influent wastewater was composed of 800 mg MEA/L, 430 mg DMSO/L, and 90 mg TMAH/L, respectively. After reaching steady-state, SBR was able to achieve more than 99% degradation efficiencies for the three compounds examined. For the case of aerobic MBR, the influent wastewater was composed of 550 mg MEA/L, 270 mg DMSO/L, and 330 mg TMAH/L, respectively, and degradation efficiencies for the three compounds achieved more than 99%. Although both different reactors shared similar and satisfactory degradation efficiencies for DMSO, MEA, and TMAH, the microbial ecology of these two reactors, as elucidated with molecular methods, was apparently different. The 16S rDNA-based cloning/sequencing results indicated that the dominant sequences retrieved from the aerobic MBR, including Hyphomicrobium denitrificans, Hyphomicrobium zavarzinii, Rhodobacter sp., and Methyloversatilis universalis, showed a clear linkage to their physiological properties of DMSO and TMAH degradation. On the other hand, Zoogloea sp., Chlorobium chlorochromatii, Agricultural soil bacterium, and Flavosolibacter ginsengiterrae were proliferated in the A/O SBR Run1, while Thiobacillus sp., Nitrosomonas sp., Thauera aromatica and Azoarcus

  5. 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.

  6. 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.

  7. 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.

  8. Membrane damage and viability loss of Escherichia coli K-12 and Salmonella entertidis in liquid egg by thermal death time disk treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data on mechanisms of bacteria inactivation by heat using the Thermal-Death-Time (TDT) disk method are limited and is urgently needed by the regulatory agencies. In order to understand the mechanism of inactivation of bacteria by heat using the TDT disk processing, liquid egg white and liquid whole ...

  9. Quantitative transporter proteomics by liquid chromatography with tandem mass spectrometry: addressing methodologic issues of plasma membrane isolation and expression-activity relationship.

    PubMed

    Kumar, Vineet; Prasad, Bhagwat; Patilea, Gabriela; Gupta, Anshul; Salphati, Laurent; Evers, Raymond; Hop, Cornelis E C A; Unadkat, Jashvant D

    2015-02-01

    To predict transporter-mediated drug disposition using physiologically based pharmacokinetic models, one approach is to measure transport activity and relate it to protein expression levels in cell lines (overexpressing the transporter) and then scale these to via in vitro to in vivo extrapolation (IVIVE). This approach makes two major assumptions. First, that the expression of the transporter is predominantly in the plasma membrane. Second, that there is a linear correlation between expression level and activity of the transporter protein. The present study was conducted to test these two assumptions. We evaluated two commercially available kits that claimed to separate plasma membrane from other cell membranes. The Qiagen Qproteome kit yielded very little protein in the fraction purported to be the plasma membrane. The Abcam Phase Separation kit enriched the plasma membrane but did not separate it from other intracellular membranes. For the Abcam method, the expression level of organic anion-transporting polypeptides (OATP) 1B1/2B1 and breast cancer resistance protein (BCRP) proteins in all subcellular fractions isolated from cells or human liver tissue tracked that of Na⁺-K⁺ ATPase. Assuming that Na⁺-K⁺ ATPase is predominantly located in the plasma membrane, these data suggest that the transporters measured are also primarily located in the plasma membrane. Using short hairpin RNA, we created clones of cell lines with varying degrees of OATP1B1 or BCRP expression level. In these clones, transport activity of OATP1B1 or BCRP was highly correlated with protein expression level (r² > 0.9). These data support the use of transporter expression level data and activity data from transporter overexpressing cell lines for IVIVE of transporter-mediated disposition of drugs.

  10. Synthesis and crystal structure of a new N-(2,6-dichlorobenzoyl)- N', N″-bis(pyrrolidinyl)-phosphoric triamide as a carrier and competitive bulk liquid membrane transport of six metal cations

    NASA Astrophysics Data System (ADS)

    Khoshnood, Razieh Sanavi; Pourayoubi, Mehrdad; Kasraee, Farideh; Toghraee, Maryam; Dušek, M.; Bereciartua, P. J.

    2014-12-01

    The competitive metal ion transport experiments of Co+2, Cd+2, Ag+, Pb+2, Ni+2, and Cu+2 were carried out by N-(2,6-dichlorobenzoyl)- N', N″-bis(pyrrolidinyl)-phosphoric triamide as a carrier in organic membrane phase. 2,6-Cl2C6H3C(O)NHP(O)[NC4H8]2 has been synthesized and characterized by mass spectrometry IR spectroscopy and single crystal X-ray diffraction. The asymmetric unit of title phosphoric triamide contains one symmetrically independent molecule. The source phase contained equimolar concentrations of metal ions at pH 5 and the receiving phase being buffered at pH 3. The following solvents were examined as membrane: chloroform (CHCl3), nitrobenzene (NB), 1,2-dichloroethane (1,2-DCE), dichloromethane (DCM), dichloromethane/1,2-dichloroethane (DCM/1,2-DCE). The obtained results show that the selectivity and efficiency of transport for these heavy metal cations change with the nature of the ligand and also the organic solvents, which were used as liquid membrane in these experiments. A good selectivity was observed for Pb+2 cation by this ligand in all membrane systems. Moreover, the selectivity of metal cations in DCM is higher than other solvents. A non-linear relationship was found between the percent of transport of Pb+2 cation by this ligand and the compositions of DCM/1,2-DCE and binary solution by this ligand. The effect of several factors such as the nature of carboxylic acids (stearic, fumaric and maleic acid) as surfactant in the membrane phase and the time of transport on transport efficiency of Pb+2 cation were investigated.

  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

    Semrau, Stefan; Idema, Timon; Schmidt, Thomas; Storm, Cornelis

    2009-06-17

    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.

  14. Temperature polarization coefficients in membrane distillation

    SciTech Connect

    Martinez-Diez, L.; Vazquez-Gonzalez, M.I.; Florido-Diaz, F.J.

    1998-04-01

    Membrane distillation is a membrane process in which two liquid phases at different temperatures are separated by a microporous hydrophobic membrane. The membrane plays the role of a physical support for the vapor-liquid interface. The aim of this paper is to study pure water transport by membrane distillation through a PTFE flat membrane. The dependence of the phenomenon on average temperature and recirculation rate at the membrane sides is investigated. The influence of these operating conditions on water transport is discussed by taking into account mass and heat transfer within the membrane and the adjoining liquid phases. The concept of temperature polarization is introduced into the transport equations and shown to be important in the interpretation of the experimental results.

  15. 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.

  16. 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

    PubMed Central

    Gupta, S.; Liu, J.; Strzalka, J.; Blasie, J. K.

    2011-01-01

    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

  17. On-line detection of hippuric acid by microextraction with a molecularly-imprinted polysulfone membrane sorbent and liquid chromatography-tandem mass spectrometry.

    PubMed

    Moein, Mohammad Mahdi; El-Beqqali, Aziza; Javanbakht, Mehran; Karimi, Mohammad; Akbari-Adergani, Behrouz; Abdel-Rehim, Mohamed

    2014-10-30

    Destruction of sorbents during consecutive extractions using the micro-extraction by packed sorbent (MEPS) technique is a serious problem. In MEPS the complex matrix such as plasma and blood can affect the sorbent physical properties and the sorbent can be deteriorated after handling of few samples. To overcome this problem, the surface of a polysulfone membrane (PSM) was modified by a molecularly imprinted sol-gel and utilized for online extraction of a lung cancer biomarker, hippuric acid (HA), in biological matrices. The molecularly imprinted polymer membrane provided fast, sensitive, selective and robust sample preparation method for HA in biological fluids. In addition, MIP membrane could be used for up to 50 extractions without a significant change in extraction recovery. To achieve the best results, the parameters that influenced the extraction efficiency were thoroughly investigated. Moreover, for evaluating the performance of the molecularly imprinted sol-gel membrane (MISM), a non-molecularly imprinted sol-gel membrane (NISM) as a blank was prepared. The limits of detection (LOD) and quantification (LOQ) for HA in both plasma and urine samples were 0.30nmolL(-1) and 1.0nmolL(-1), respectively. Standard calibration curves were obtained over the range of 1-1000nmolL(-1) for HA in plasma and urine samples. The coefficients of determination (R(2)) were ≥0.997. The extraction recoveries of HA from human plasma and urine samples were higher than 91%. The precision values for HA in plasma and urine samples were 2.2-4.8% and 1.1-6.7%, respectively. PMID:25468498

  18. Membranebioreactor with external membranes.

    PubMed

    Jonkers, C; Carrette, R; De Lathouwer, J; Thoeye, C

    2001-01-01

    The recent development of less expensive and more performant ultrafiltration membranes has generated a new concept in biological treatment known as membrane bioreactors (MBR). In the field of wastewater treatment, the MBR process is used as a modification of the conventional activated sludge (CAS) process, where the clarifier is replaced by a membrane module for the separation of the solid and the liquid phase. Membrane technology can, amongst others, be applied for the fast retrofit of relatively high loaded activated sludge systems to nutrient removal. In the last year Aquafin has built up extensive experience with submerged membrane systems. The research presented here was aimed at evaluating a particular external tubular membrane unit for MBR. More specifically it was evaluated whether higher stable flux levels could compensate the higher energy consumption, typical for external membrane systems. Both (1) treatment performance and (2) possible operational drawbacks were tested on a 5 m3/h activated sludge pilot-scale. The membrane bioreactor was tested in parallel with a conventional activated sludge system.

  19. 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)

  20. 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.

  1. 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.

  2. 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.

  3. 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. PMID:27175515

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Determination of non-steroidal anti-inflammatory drugs in urine by hollow-fiber liquid membrane-protected solid-phase microextraction based on sol-gel fiber coating.

    PubMed

    Sarafraz-Yazdi, Ali; Amiri, Amirhassan; Rounaghi, Gholamhossein; Eshtiagh-Hosseini, Hossein

    2012-11-01

    A new rapid, simple and effective cleanup procedure is demonstrated for the determination of ibuprofen, naproxen and diclofenac in urine samples by using hollow-fiber liquid membrane-protected solid-phase microextraction (HFLM-SPME) based on sol-gel technique and gas chromatography-flame ionization detector (GC-FID). In this technique, a sol-gel coated 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 urine sample for extraction. Poly(ethylene glycol) (PEG) grafted onto multi-walled carbon nanotubes (PEG-g-MWCNTs) was used as extraction phase to prepare the sol-gel SPME fiber. Important parameters influencing the extraction efficiency such as desorption temperature and time, organic solvent, extraction temperature and time, pH, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits (S/N=3) were in the range of 0.03-0.07ngmL(-1) and the limits of quantification (S/N=10) between 0.08 and 0.15ngmL(-1). Relative standard deviations for intra-day and inter-day precisions were 4.8-9.0% and 4.9-8.1%, respectively. Subsequently, the method was successfully applied to human urine fractions after administration of ibuprofen, naproxen and diclofenac.

  9. 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.

  10. Membrane photobiophysics and photochemistry

    NASA Astrophysics Data System (ADS)

    Ti Tien, H.

    Life, as we know it, depends on solar energy, in particular in the visible range of the solar spectrum. However, visible light alone is useless to the living organism unless a means is available for its capture, transformation, and utilization. Nature, through its long evolution, has perfected a process known as photosynthesis by which visible light is transduced into electrical/ chemical energy. However, the heart of Nature's energy transducer is the thylakoid membrane whose molecular organization was not known until early in the 1960s. Then it was established that the bilayer lipid membrane was central to the design of the thylakoid membrane. To explain the light-driven reactions from water oxidation to carbon dioxide reduction, the so-called Z-scheme was proposed. Concurrent with the establishment of Mitchell's Chemiosmotic Hypothesis for electron transfer and phosphorylation, the experimental bilayer lipid membrane (BLM) system was developed in 1960. But what are the fundamental biophysical mechanisms involved in the phototransduction via pigmented bilayer lipid membrane-based transducers? One of the main purposes of this review is to consider these questions. A second main purpose is to introduce to the reader the experimental aspects of lipid bilayers in the investigation of photoactive biomembranes. The areas covered in this review include a brief summary of the laws of photochemistry relevant to membrane photobiophysics and photobiology. The current exploitation of the BLM system in relation to the thylakoid membrane and to the visual receptor membrane will be considered in turn. The purple membrane of H. Halobium is then discussed. Consideration will also be given to dye-sensitized BLMs, semiconducting BLMs, and BLMs formed from liquid crystals. A common characteristic in the topics covered in this review is the desire to stimulate further studies in the use of the BLM system, not only for the fundamental understanding of biomembranes, but also towards

  11. 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).

  12. Membrane tension and membrane fusion.

    PubMed

    Kozlov, Michael M; Chernomordik, Leonid V

    2015-08-01

    Diverse cell biological processes that involve shaping and remodeling of cell membranes are regulated by membrane lateral tension. Here we focus on the role of tension in driving membrane fusion. We discuss the physics of membrane tension, forces that can generate the tension in plasma membrane of a cell, and the hypothesis that tension powers expansion of membrane fusion pores in late stages of cell-to-cell and exocytotic fusion. We propose that fusion pore expansion can require unusually large membrane tensions or, alternatively, low line tensions of the pore resulting from accumulation in the pore rim of membrane-bending proteins. Increase of the inter-membrane distance facilitates the reaction. PMID:26282924

  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. 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.

  17. 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.

  18. Membrane distillation

    NASA Astrophysics Data System (ADS)

    Bryk, Mikhail T.; Nigmatullin, R. R.

    1994-12-01

    Studies in the field of membrane distillation are analysed. A critical analysis of the theoretical and experimental investigations of membrane distillation is presented. Attention is concentrated on the mechanism of mass transfer and the influence of various external factors on the process characteristics. Questions concerning the creation of modules and apparatus for membrane distillation and aspects of the practical employment of such distillation in order to obtain pure water, for the purification of waste water, and for the concentration of technological solutions in various branches of industry are considered quite fully. The advantages and disadvantages of membrane distillation compared with other membrane methods are analysed. The bibliography includes 97 references.

  19. 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

  20. 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.

  1. Liquid-immersible electrostatic ultrasonic transducer

    NASA Technical Reports Server (NTRS)

    Cantrell, J. H., Jr.; Heyman, J. S.; Yost, W. T.; Torbett, M. A.; Breazeale, M. A. (Inventor)

    1982-01-01

    A broadband megahertz range electrostatic acoustic transducer for use in a liquid environment is described. A liquid tight enclosure includes a metallic conducting membrane as part of its outside surface and has a means inside the liquid tight enclosure for applying a tension to the membrane and for mounting an electrode such that the flat end of the electrode is aproximately parallel to the membrane. The invention includes structure and a method for ensuring that the membrane and the flat end of the electrode are exactly parallel and a fixed predetermined distance from each other.

  2. Membrane Processes.

    PubMed

    Pellegrin, Marie-Laure; Sadler, Mary E; Greiner, Anthony D; Aguinaldo, Jorge; Min, Kyungnan; Zhang, Kai; Arabi, Sara; Burbano, Marie S; Kent, Fraser; Shoaf, Robert

    2015-10-01

    This review, for literature published in 2014, contains information related to membrane processes for municipal and industrial applications. This review is a subsection of the Treatment Systems section of the annual Water Environment Federation literature review and covers the following topics: pretreatment, membrane bioreactor (MBR) configuration, design, nutrient removal, operation, industrial treatment, fixed film and anaerobic membrane systems, reuse, microconstituents removal, membrane technology advances, membrane fouling, and modeling. Other sub-sections of the Treatment Systems section that might relate to this literature review include: Biological Fixed-Film Systems, Activated Sludge and Other Aerobic Suspended Culture Processes, Anaerobic Processes, Water Reclamation and Reuse. The following sections might also have related information on membrane processes: Industrial Wastes, Hazardous Wastes, and Fate and Effects of Pollutants. PMID:26420079

  3. Membrane Processes.

    PubMed

    Pellegrin, Marie-Laure; Burbano, Marie S; Sadler, Mary E; Diamond, Jason; Baker, Simon; Greiner, Anthony D; Arabi, Sara; Wong, Joseph; Doody, Alexandra; Padhye, Lokesh P; Sears, Keith; Kistenmacher, Peter; Kent, Fraser; Tootchi, Leila; Aguinaldo, Jorge; Saddredini, Sara; Schilling, Bill; Min, Kyungnan; McCandless, Robert; Danker, Bryce; Gamage, Neranga P; Wang, Sunny; Aerts, Peter

    2016-10-01

    This review, for literature published in 2015, contains information related to membrane processes for municipal and industrial applications. This review is a subsection of the Treatment Systems section of the annual Water Environment Federation literature review and covers the following topics: pretreatment, membrane bioreactor (MBR) configuration, design, nutrient removal, operation, industrial treatment, anaerobic membrane systems, reuse, microconstituents removal, membrane technology advances, membrane fouling, and modeling. Other sub-sections of the Treatment Systems section that might relate to this literature review include: Biological Fixed-Film Systems, Activated Sludge and Other Aerobic Suspended Culture Processes, Anaerobic Processes, Water Reclamation and Reuse. The following sections might also have related information on membrane processes: Industrial Wastes, Hazardous Wastes, and Fate and Effects of Pollutants. PMID:27620084

  4. 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.

  5. 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.

  6. Characterization of drug-protein binding process by employing equilibrium sampling through hollow-fiber supported liquid membrane and Bjerrum and Scatchard plots.

    PubMed

    Barri, Thaer; Trtić-Petrović, Tatjana; Karlsson, Michael; Jönsson, Jan Ake

    2008-09-10

    The technique equilibrium sampling through membrane (ESTM) was extended to measuring the free drug concentration in solutions of drug and protein. Bjerrum and Scatchard plots were employed for characterizing individual drug binding to pure human blood proteins. Four drugs were investigated as a model system: fluvoxamine and ropivacaine which dominantly bind to alpha-acid glycoprotein (AGP), and R,S-ibuprofen and S-ketoprofen which highly bind to human serum albumin (HSA). The level of drug binding to AGP and HSA relied on drug and protein concentrations. Bjerrum and Scatchard plots revealed high affinity constants (Ka) at low protein concentration. Both Bjerrum and Scatchard plots of fluvoxamine and ropivacaine binding to AGP showed one specific binding site (n1=1) with ropivacaine Ka value close to 5 times higher than the Ka of fluvoxamine at 22.9 microM AGP concentration. Bjerrum plots of ketoprofen and ibuprofen gave total number of binding sites or bound molecules of 6-7, which did not depend on the drug or protein concentration. Scatchard plots of ketoprofen and ibuprofen exhibited two binding sites (n1 and n2) at 0.15 microM and 0.75 microM HSA concentrations. On one hand, at 0.15 microM HSA, ketoprofen and ibuprofen were bound to site I at n1=1.2 and n1=1.0, respectively. However, at 0.75 microM HSA, ketoprofen and ibuprofen were bound to site I at n1=1.2 and n1=1.9, respectively. On the other hand, site II, at 0.15 microM HSA, interacted with ketoprofen and ibuprofen at n2=5.6 and 6.7, respectively. However, at 0.75 microM HSA, site II interacted with ketoprofen at n2=7.4 and ibuprofen at n2=6.2. It would be concluded that, upon mixing ketoprofen and ibuprofen in a HSA solution, a ketoprofen-ibuprofen interaction would most likely occur at site II in HSA. PMID:18565712

  7. Charged membranes.

    PubMed

    Thatcher, Jack D

    2013-04-16

    This Teaching Resource provides three animated lessons that describe the storage and utilization of energy across plasma membranes. The "Na,K ATPase" animation explains how these pumps establish the electrochemical gradient that stores energy across plasma membranes. The "ATP synthesizing complexes" animation shows how these complexes transfer energy from the inner mitochondrial membrane to adenosine triphosphate (ATP). The "action potential" lesson explains how charged membranes are used to propagate signals along the axons of neurons. These animations serve as valuable resources for any collegiate-level course that describes these important factors. Courses that might employ them include introductory biology, biochemistry, biophysics, cell biology, pharmacology, and physiology.

  8. 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. PMID:26917148

  9. 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.

  10. 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.

  11. 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.

  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. 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...

  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 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Sterol evolution and the physics of membranes

    NASA Astrophysics Data System (ADS)

    Nielsen, M.; Thewalt, J.; Miao, L.; Ipsen, J. H.; Bloom, M.; Zuckermann, M. J.; Mouritsen, O. G.

    2000-11-01

    Sterols are important molecular components of the plasma membranes of eucaryotic cells. Using deuterium NMR spectroscopy in conjunction with statistical mechanical modelling, we present a unifying picture of how the evolution-engineered differences in molecular chemistry between cholesterol and its precursor lanosterol are manifested in the physical properties of model membranes in terms of molecular order and phase equilibria. Cholesterol optimizes the stability of a particular membrane phase, the liquid-ordered phase, that is a liquid and at the same time exhibits high molecular conformational order.

  1. 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

  2. Membrane Nanotubes

    NASA Astrophysics Data System (ADS)

    Derényi, I.; Koster, G.; van Duijn, M. M.; Czövek, A.; Dogterom, M.; Prost, J.

    There is a growing pool of evidence showing the biological importance of membrane nanotubes (with diameter of a few tens of nanometers and length upto tens of microns) in various intra- and intercellular transport processes. These ubiquitous structures are often formed from flat membranes by highly localized forces generated by either the pulling of motor proteins or the pushing of polymerizing cytoskeletal filaments. In this chapter we give an overview of the theory of membrane nanotubes, their biological relevance, and the most recent experiments designed for the study of their formation and dynamics. We also discuss the effect of membrane proteins or lipid composition on the shape of the tubes, and the effect of antagonistic motor proteins on tube formation.

  3. 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.

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. Mechanical properties of warped membranes.

    PubMed

    Košmrlj, Andrej; Nelson, David R

    2013-07-01

    We explore how a frozen background metric affects the mechanical properties of planar membranes with a shear modulus. We focus on a special class of "warped membranes" with a preferred random height profile characterized by random Gaussian variables h(q) in Fourier space with zero mean and variance <|h(q)|(2)>~q(-d(h)) and show that in the linear response regime the mechanical properties depend dramatically on the system size L for d(h)≥2. Membranes with d(h)=4 could be produced by flash polymerization of lyotropic smectic liquid crystals. Via a self-consistent screening approximation we find that the renormalized bending rigidity increases as κ(R)~L((d(h)-2)/2) for membranes of size L, while the Young and shear moduli decrease according to Y(R),μ(R)~L(-(d(h)-2)/2) resulting in a universal Poisson ratio. Numerical results show good agreement with analytically determined exponents.

  9. Photo-switchable membrane and method

    SciTech Connect

    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.

  10. 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 generation. Although different membranes could probably be used in a specific separation process, choosing a suitable membrane material will mainly depend on the membrane permeance and selectivity, process conditions (e.g., operating pressure, temperature) and the impurities in a gas stream (such as SO2, NOx, H2S, etc.). Moreover, process design and the challenges relevant to a membrane system are also being discussed to illustrate the membrane process feasibility for a specific application based on process simulation and economic cost estimation. PMID:24958426

  11. Polyphosphazene membranes for metal ion separations

    SciTech Connect

    Stone, M.L.

    1996-05-01

    The Idaho National Engineering Laboratory (INEL), under sponsorship by the Bureau of Mines, evaluated the use of polyphosphazene-based polymer membranes for chemical separations. Synthetic membranes based on phosphazene inorganic polymers offer the promise of new industrial chemical separation technologies that are more energy efficient and economical than traditional phase change separation processes and extraction techniques. The research focused on the separation of metal ions from aqueous solutions. The polyphosphazene membranes were also tested for gaseous separations, results of which are presented in a separate Report of Investigation. Historically, membranes used for chemical separation have been prepared from organic polymers. In general, these membranes are stable only at temperatures less than 100{degrees}C, within narrow pH ranges, and in a very limited number of organic media. As a result, many organic- based membranes are unsuitable for industrial applications, which often involve harsh environments. In recent years, membrane research has focused on ceramic and metal membranes for use in the adverse environments of separation applications. These membranes are suitable for gas and liquid sieve separation applications, where molecules may be separated based on their molecular size. These membranes are not effective where additional selectivity is needed. A membrane that separates on the basis of solubility and that can perform separations in adverse environments is needed, and this need motivated the investigation of polyphosphazene membranes.

  12. 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.

  13. Polymer single crystal membranes from curved liquid/liquid interface

    NASA Astrophysics Data System (ADS)

    Wang, Wenda; Li, Christopher; Soft Matter Research Group Team

    2014-03-01

    The weak mechanical properties of the current available vesicles such as liposomes, polymersomes, colloidosomes limit their applications for targeting delivery of drugs/genes. Recently, we developed an emulsion-crystallization method to grow polymer curved single crystals. Using polyethylene and poly(l-lactic acid)as the model systems, enclosed or partially open polymer single crystals have been obtained. Electron diffraction and XRD results confirmed their crystalline structure. The single crystal hollow sphere is structurally close to polymersomes, but with thinner wall and higher modulus.

  14. 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.

  15. Membrane thickening aerobic digestion processes.

    PubMed

    Woo, Bryen

    2014-01-01

    Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent, therefore much consideration is required when designing a solids handling process. A membrane thickening aerobic digestion process integrates a controlled aerobic digestion process with pre-thickening waste activated sludge using membrane technology. This process typically features an anoxic tank, an aerated membrane thickener operating in loop with a first-stage digester followed by second-stage digestion. Membrane thickening aerobic digestion processes can handle sludge from any liquid treatment process and is best for facilities obligated to meet low total phosphorus and nitrogen discharge limits. Membrane thickening aerobic digestion processes offer many advantages including: producing a reusable quality permeate with minimal levels of total phosphorus and nitrogen that can be recycled to the head works of a plant, protecting the performance of a biological nutrient removal liquid treatment process without requiring chemical addition, providing reliable thickening up to 4% solids concentration without the use of polymers or attention to decanting, increasing sludge storage capacities in existing tanks, minimizing the footprint of new tanks, reducing disposal costs, and providing Class B stabilization.

  16. Electroporation of heterogeneous lipid membranes.

    PubMed

    Reigada, Ramon

    2014-03-01

    Electroporation is the basis for the transfection of genetic material and for drug delivery to cells, including electrochemotherapy for cancer. By means of molecular dynamics many aspects of membrane electroporation have been unveiled at the molecular detail in simple, homogeneous, lipid bilayers. However, the correspondence of these findings \\with the process happening in cell membranes requires, at least, the consideration of laterally structured membranes. Here, I present a systematic molecular dynamics study of bilayers composed of different liquid-ordered and liquid-disordered lipid phases subjected to a transversal electric field. The simulations reveal two significant results. First, the electric field mainly affects the properties of the disordered phases, so that electroporation takes place in these membrane regions. Second, the smaller the disordered domains are, the faster they become electroporated. These findings may have a relevant significance in the experimental application of cell electroporation in vivo since it implies that electro-induced and pore-mediated transport processes occur in particularly small disordered domains of the plasma membrane, thus locally affecting only specific regions of the cell.

  17. Impact on floating membranes.

    PubMed

    Vandenberghe, Nicolas; Duchemin, Laurent

    2016-05-01

    When impacted by a rigid body, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. First, a longitudinal wave front, associated with in-plane deformation of the membrane and traveling at constant speed, separates an outward stress-free domain from a stretched domain. Then, in the stretched domain a dispersive transverse wave travels at a speed that depends on the local stretching rate. The dynamics is found to be self-similar in time. Using this property, we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. During wave propagation, we observe the development of a buckling instability that gives rise to radial wrinkles. We address the dynamics of this fluid-body system, including the rapid deceleration of an impactor of finite mass, an issue that may have applications in the domain of absorption of impact energy. PMID:27300958

  18. Electrospun superhydrophobic membranes with unique structures for membrane distillation.

    PubMed

    Liao, Yuan; Loh, Chun-Heng; Wang, Rong; Fane, Anthony G

    2014-09-24

    With modest temperature demand, low operating pressure, and high solute rejection, membrane distillation (MD) is an attractive option for desalination, waste treatment, and food and pharmaceutical processing. However, large-scale practical applications of MD are still hindered by the absence of effective membranes with high hydrophobicity, high porosity, and adequate mechanical strength, which are important properties for MD permeation fluxes, stable long-term performance, and effective packing in modules without damage. This study describes novel design strategies for highly robust superhydrophobic dual-layer membranes for MD via electrospinning. One of the newly developed membranes comprises a durable and ultrathin 3-dimensional (3D) superhydrophobic skin and porous nanofibrous support whereas another was fabricated by electrospinning 3D superhydrophobic layers on a nonwoven support. These membranes exhibit superhydrophobicity toward distilled water, salty water, oil-in-water emulsion, and beverages, which enables them to be used not only for desalination but also for other processes. The superhydrophobic dual-layer membrane #3S-N with nanofibrous support has a competitive permeation flux of 24.6 ± 1.2 kg m(-2) h(-1) in MD (feed and permeate temperate were set as 333 and 293 K, respectively) due to the higher porosity of the nanofibrous scaffold. Meanwhile, the membranes with the nonwoven support exhibit greater mechanical strength due to this support combined with better long-term performance because of the thicker 3D superhydrophobic layers. The morphology, pore size, porosity, mechanical properties, and liquid enter pressure of water of these superhydrophobic composite membranes with two different structures are reported and compared with commercial polyvinylidene fluoride membranes. PMID:25147909

  19. Electrospun superhydrophobic membranes with unique structures for membrane distillation.

    PubMed

    Liao, Yuan; Loh, Chun-Heng; Wang, Rong; Fane, Anthony G

    2014-09-24

    With modest temperature demand, low operating pressure, and high solute rejection, membrane distillation (MD) is an attractive option for desalination, waste treatment, and food and pharmaceutical processing. However, large-scale practical applications of MD are still hindered by the absence of effective membranes with high hydrophobicity, high porosity, and adequate mechanical strength, which are important properties for MD permeation fluxes, stable long-term performance, and effective packing in modules without damage. This study describes novel design strategies for highly robust superhydrophobic dual-layer membranes for MD via electrospinning. One of the newly developed membranes comprises a durable and ultrathin 3-dimensional (3D) superhydrophobic skin and porous nanofibrous support whereas another was fabricated by electrospinning 3D superhydrophobic layers on a nonwoven support. These membranes exhibit superhydrophobicity toward distilled water, salty water, oil-in-water emulsion, and beverages, which enables them to be used not only for desalination but also for other processes. The superhydrophobic dual-layer membrane #3S-N with nanofibrous support has a competitive permeation flux of 24.6 ± 1.2 kg m(-2) h(-1) in MD (feed and permeate temperate were set as 333 and 293 K, respectively) due to the higher porosity of the nanofibrous scaffold. Meanwhile, the membranes with the nonwoven support exhibit greater mechanical strength due to this support combined with better long-term performance because of the thicker 3D superhydrophobic layers. The morphology, pore size, porosity, mechanical properties, and liquid enter pressure of water of these superhydrophobic composite membranes with two different structures are reported and compared with commercial polyvinylidene fluoride membranes.

  20. Interaction of abscisic acid with phospholipid membranes

    SciTech Connect

    Stillwell, W.; Brengle, B.; Hester, P.; Wassall, S.T. )

    1989-04-04

    The plant hormone abscisic acid (ABA) is shown, under certain conditions, to greatly enhance the permeability of phospholipid bilayer membranes to the nonelectrolyte erythritol (followed spectrophotometrically by osmotic swelling) and the anion carboxyfluorescein (followed by fluorescence). The hormone is ineffective with single- and mixed-component phosphatidylcholine membranes in the liquid-crystalline or gel states. In contrast, substantial ABA-induced permeability is measured for two-component membranes containing lipids with different polar head groups or containing phosphatidylcholines with different acyl chains at temperatures where gel and liquid-crystalline phases coexist. Despite the large ABA-induced enhancement in bilayer permeability, no evidence for a substantial change at the molecular level was seen in the membranes by magnetic resonance techniques. {sup 13}C NMR spin-lattice relaxation times, T{sub 1}, in sonicated unilamellar vesicles and ESR of spin-labeled fatty acids intercalated into membranes showed negligible effect on acyl chain order and dynamics within the bilayer, while {sup 31}P NMR of sonicated unilamellar vesicles indicated negligible effect on molecular motion and conformation in the head-group region. The authors propose that, instead of causing a general nonspecific perturbation to the membrane, the hormone acts at membrane defects formed due to mismatch in molecular packing where two different head groups or acyl chain states interface. Increased membrane disruption by ABA at these points of membrane instability could then produce an enhancement in permeability.

  1. Water desalination using carbon-nanotube-enhanced membrane distillation.

    PubMed

    Gethard, Ken; Sae-Khow, Ornthida; Mitra, Somenath

    2011-02-01

    Carbon nanotube (CNT) enhanced membrane distillation is presented for water desalination. It is demonstrated that the immobilization of the CNTs in the pores of a hydrophobic membrane favorably alters the water-membrane interactions to promote vapor permeability while preventing liquid penetration into the membrane pores. For a salt concentration of 34 000 mg L(-1) and at 80 °C, the nanotube incorporation led to 1.85 and 15 times increase in flux and salt reduction, respectively. PMID:21188976

  2. Water desalination using carbon-nanotube-enhanced membrane distillation.

    PubMed

    Gethard, Ken; Sae-Khow, Ornthida; Mitra, Somenath

    2011-02-01

    Carbon nanotube (CNT) enhanced membrane distillation is presented for water desalination. It is demonstrated that the immobilization of the CNTs in the pores of a hydrophobic membrane favorably alters the water-membrane interactions to promote vapor permeability while preventing liquid penetration into the membrane pores. For a salt concentration of 34 000 mg L(-1) and at 80 °C, the nanotube incorporation led to 1.85 and 15 times increase in flux and salt reduction, respectively.

  3. Membrane magic

    SciTech Connect

    Buecker, B.

    2005-09-01

    The Kansas Power and Light Co.'s La Cyne generating station has found success with membrane filtration water pretreatment technology. The article recounts the process followed in late 2004 to install a Pall Aria 4 microfilter in Unit 1 makeup water system at the plant to produce cleaner water for reverse osmosis feed. 2 figs., 2 photos.

  4. A submerged membrane bioreactor with pendulum type oscillation (PTO) for oily wastewater treatment: membrane permeability and fouling control.

    PubMed

    Qin, Lei; Fan, Zheng; Xu, Lusheng; Zhang, Guoliang; Wang, Guanghui; Wu, Dexin; Long, Xuwei; Meng, Qin

    2015-05-01

    In this study, a novel submerged membrane bioreactor (SMBR) with pendulum type oscillation (PTO) hollow fiber membrane modules was developed to treat oily wastewater and control the problem of membrane fouling. To assess the potential of PTO membrane modules, the effect of oscillation orientation and frequency on membrane permeability was investigated in detail. The forces exerted on sludge flocs in the oscillating SMBR were analyzed to evaluate the impact of membrane oscillating on the cake layer resistance reduction. Results showed that the optimized PTO SMBR system exhibited 11 times higher membrane permeability and better fouling controllability than the conventional MBR system. By hydrodynamic analysis, it was found that the cooperative effect of bubble-induced turbulence and membrane oscillation in PTO SMBR system generated strong shear stress at liquid-membrane interface in vertical and horizontal direction and effectively hindered the particles from depositing on membrane surface.

  5. Superbase-derived protic ionic liquids

    DOEpatents

    Dai, Sheng; Luo, Huimin; Baker, Gary A.

    2013-09-03

    Protic ionic liquids having a composition of formula (A.sup.-)(BH.sup.+) wherein A.sup.- is a conjugate base of an acid HA, and BH.sup.+ is a conjugate acid of a superbase B. In particular embodiments, BH.sup.+ is selected from phosphazenium species and guanidinium species encompassed, respectively, by the general formulas: ##STR00001## The invention is also directed to films and membranes containing these protic ionic liquids, with particular application as proton exchange membranes for fuel cells.

  6. Membranes for nanometer-scale mass fast transport

    DOEpatents

    Bakajin, Olgica; Holt, Jason; Noy, Aleksandr; Park, Hyung Gyu

    2011-10-18

    Nanoporous membranes comprising single walled, double walled, and multiwalled carbon nanotubes embedded in a matrix material were fabricated for fluid mechanics and mass transfer studies on the nanometer scale and commercial applications. Average pore size can be 2 nm to 20 nm, or seven nm or less, or two nanometers or less. The membrane can be free of large voids spanning the membrane such that transport of material such as gas or liquid occurs exclusively through the tubes. Fast fluid, vapor, and liquid transport are observed. Versatile micromachining methods can be used for membrane fabrication. A single chip can comprise multiple membranes. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

  7. Lipid organization of the plasma membrane.

    PubMed

    Ingólfsson, Helgi I; Melo, Manuel N; van Eerden, Floris J; Arnarez, Clément; Lopez, Cesar A; Wassenaar, Tsjerk A; Periole, Xavier; de Vries, Alex H; Tieleman, D Peter; Marrink, Siewert J

    2014-10-15

    The detailed organization of cellular membranes remains rather elusive. Based on large-scale molecular dynamics simulations, we provide a high-resolution view of the lipid organization of a plasma membrane at an unprecedented level of complexity. Our plasma membrane model consists of 63 different lipid species, combining 14 types of headgroups and 11 types of tails asymmetrically distributed across the two leaflets, closely mimicking an idealized mammalian plasma membrane. We observe an enrichment of cholesterol in the outer leaflet and a general non-ideal lateral mixing of the different lipid species. Transient domains with liquid-ordered character form and disappear on the microsecond time scale. These domains are coupled across the two membrane leaflets. In the outer leaflet, distinct nanodomains consisting of gangliosides are observed. Phosphoinositides show preferential clustering in the inner leaflet. Our data provide a key view on the lateral organization of lipids in one of life's fundamental structures, the cell membrane.

  8. Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

    PubMed

    Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

    2016-07-01

    Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake.

  9. Biofouling behavior and performance of forward osmosis membranes with bioinspired surface modification in osmotic membrane bioreactor.

    PubMed

    Li, Fang; Cheng, Qianxun; Tian, Qing; Yang, Bo; Chen, Qianyuan

    2016-07-01

    Forward osmosis (FO) has received considerable interest for water and energy related applications in recent years. Biofouling behavior and performance of cellulose triacetate (CTA) forward osmosis membranes with bioinspired surface modification via polydopamine (PD) coating and poly (ethylene glycol) (PEG) grafting (PD-g-PEG) in a submerged osmotic membrane bioreactor (OMBR) were investigated in this work. The modified membranes exhibited lower flux decline than the pristine one in OMBR, confirming that the bioinspired surface modification improved the antifouling ability of the CTA FO membrane. The result showed that the decline of membrane flux related to the increase of the salinity and MLSS concentration of the mixed liquid. It was concluded that the antifouling ability of modified membranes ascribed to the change of surface morphology in addition to the improvement of membrane hydrophilicity. The bioinspired surface modifications might improve the anti-adhesion for the biopolymers and biocake. PMID:27089532

  10. Sweeping Gas Membrane Desalination Using Commercial Hydrophobic Hollow Fiber Membranes

    SciTech Connect

    EVANS, LINDSEY; MILLER, JAMES E.

    2002-01-01

    Water shortages affect 88 developing countries that are home to half of the world's population. In these places, 80-90% of all diseases and 30% of all deaths result from poor water quality. Furthermore, over the next 25 years, the number of people affected by severe water shortages is expected to increase fourfold. Low cost methods of purifying freshwater, and desalting seawater are required to contend with this destabilizing trend. Membrane distillation (MD) is an emerging technology for separations that are traditionally accomplished via conventional distillation or reverse osmosis. As applied to desalination, MD involves the transport of water vapor from a saline solution through the pores of a hydrophobic membrane. In sweeping gas MD, a flowing gas stream is used to flush the water vapor from the permeate side of the membrane, thereby maintaining the vapor pressure gradient necessary for mass transfer. Since liquid does not penetrate the hydrophobic membrane, dissolved ions are completely rejected by the membrane. MD has a number of potential advantages over conventional desalination including low temperature and pressure operation, reduced membrane strength requirements, compact size, and 100% rejection of non-volatiles. The present work evaluated the suitability of commercially available technology for sweeping gas membrane desalination. Evaluations were conducted with Celgard Liqui-Cel{reg_sign} Extra-Flow 2.5X8 membrane contactors with X-30 and X-40 hydrophobic hollow fiber membranes. Our results show that sweeping gas membrane desalination systems are capable of producing low total dissolved solids (TDS) water, typically 10 ppm or less, from seawater, using low grade heat. However, there are several barriers that currently prevent sweeping gas MD from being a viable desalination technology. The primary problem is that large air flows are required to achieve significant water yields, and the costs associated with transporting this air are prohibitive. To

  11. [Membranous nephropathy].

    PubMed

    Mercadal, Lucile

    2013-12-01

    Membranous nephropathy is characterized by immune complex deposits on the outer side of the glomerular basement membrane. Activation of complement and of oxidation lead to basement membrane lesions. The most frequent form is idiopathic. At 5 and 10 years, renal survival is around 90 and 65% respectively. A prognostic model based on proteinuria, level and duration, progression of renal failure in a few months can refine prognosis. The urinary excretion of C5b-9, β2 and α1 microglobuline and IgG are strong predictors of outcome. Symptomatic treatment is based on anticoagulation in case of nephrotic syndrome, angiotensin conversion enzyme inhibitors, angiotensin II receptor blockers and statins. Immunosuppressive therapy should be discussed for patients having a high risk of progression. Corticoids alone has no indication. Treatment should include a simultaneous association or more often alternating corticoids and alkylant agent for a minimum of 6 months. Adrenocorticoid stimulating hormone and steroids plus mycophenolate mofetil may be equally effective. Steroids plus alkylant decrease the risk of end stage renal failure. Cyclosporine and tacrolimus decrease proteinuria but are associated with a high risk of recurrence at time of withdrawal and are nephrotoxic. Rituximab evaluated on open studies needs further evaluations to define its use.

  12. Self-assembly of Fmoc-diphenylalanine inside liquid marbles.

    PubMed

    Braun, Hans-Georg; Cardoso, André Zamith

    2012-09-01

    Liquid marbles made from Lycopodium clavatum spores are used to encapsulate aqueous solutions of 9-fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF). Acidification of the Fmoc-FF solution at the liquid/air interface of the liquid marble triggers the self-assembly of ribbon-like peptide fibrils into an ultrathin peptide membrane (50-500 nm). The membrane incorporates the lycopodium microparticles and as a result stabilizes the liquid marble against collapse, that could otherwise occur through particle disintegration at the floating interphase. Ultrathin nanostructured peptide membrane formation at the liquid/air interface is also observed within artificial microstructured floating objects. Thus, peptide membranes formed were inspected by SEM and TEM. Electron diffraction data reveal information about the molecular organization inside the oligopeptide membranes.

  13. Liquid-liquid extraction for surfactant-contaminant separation and surfactant reuse

    SciTech Connect

    Hasegawa, M.A.; Sabatini, D.A.; Harwell, J.H.

    1997-07-01

    Liquid-liquid extraction was investigated for use with surfactant enhanced subsurface remediation. A surfactant liquid-liquid extraction model (SLLEM) was developed for batch equilibrium conditions based on contaminant partitioning between micellar, water, and solvent phases. The accuracy of this fundamental model was corroborated with experimental results (using naphthalene and phenanthrene as contaminants and squalane as the extracting solvent). The SLLEM model was then expanded to nonequilibrium conditions. The effectiveness of this nonequilibrium model was corroborated with experimental results from continuous flow hollow fiber membrane systems. The validated models were used to conduct a sensitivity analysis evaluating the effects of surfactants on the removal of the contaminants in liquid-liquid extraction systems. In addition, liquid-liquid extraction is compared to air stripping for surfactant-contaminant separation. Finally, conclusions are drawn as to the impact of surfactants on liquid-liquid extraction processes, and the significance of these impacts on the optimization of surfactant-enhanced subsurface remediation.

  14. Order of lipid phases in model and plasma membranes

    PubMed Central

    Kaiser, Hermann-Josef; Lingwood, Daniel; Levental, Ilya; Sampaio, Julio L.; Kalvodova, Lucie; Rajendran, Lawrence; Simons, Kai

    2009-01-01

    Lipid rafts are nanoscopic assemblies of sphingolipids, cholesterol, and specific membrane proteins that contribute to lateral heterogeneity in eukaryotic membranes. Separation of artificial membranes into liquid-ordered (Lo) and liquid-disordered phases is regarded as a common model for this compartmentalization. However, tight lipid packing in Lo phases seems to conflict with efficient partitioning of raft-associated transmembrane (TM) proteins. To assess membrane order as a component of raft organization, we performed fluorescence spectroscopy and microscopy with the membrane probes Laurdan and C-laurdan. First, we assessed lipid packing in model membranes of various compositions and found cholesterol and acyl chain dependence of membrane order. Then we probed cell membranes by using two novel systems that exhibit inducible phase separation: giant plasma membrane vesicles [Baumgart et al. (2007) Proc Natl Acad Sci USA 104:3165–3170] and plasma membrane spheres. Notably, only the latter support selective inclusion of raft TM proteins with the ganglioside GM1 into one phase. We measured comparable small differences in order between the separated phases of both biomembranes. Lateral packing in the ordered phase of giant plasma membrane vesicles resembled the Lo domain of model membranes, whereas the GM1 phase in plasma membrane spheres exhibited considerably lower order, consistent with different partitioning of lipid and TM protein markers. Thus, lipid-mediated coalescence of the GM1 raft domain seems to be distinct from the formation of a Lo phase, suggesting additional interactions between proteins and lipids to be effective. PMID:19805351

  15. Proton Exchange Membranes for Fuel Cells

    SciTech Connect

    Devanathan, Ramaswami

    2010-11-01

    Proton exchange membrane, also known as polymer electrolyte membrane, fuel cells (PEMFCs) offer the promise of efficient conversion of chemical energy of fuel, such as hydrogen or methanol, into electricity with minimal pollution. Their widespread use to power zero-emission automobiles as part of a hydrogen economy can contribute to enhanced energy security and reduction in greenhouse gas emissions. However, the commercial viability of PEMFC technology is hindered by high cost associated with the membrane electrode assembly (MEA) and poor membrane durability under prolonged operation at elevated temperature. Membranes for automotive fuel cell applications need to perform well over a period comparable to the life of an automotive engine and under heavy load cycling including start-stop cycling under sub-freezing conditions. The combination of elevated temperature, changes in humidity levels, physical stresses and harsh chemical environment contribute to membrane degradation. Perfluorinated sulfonic acid (PFSA)-based membranes, such as Nafion®, have been the mainstay of PEMFC technology. Their limitations, in terms of cost and poor conductivity at low hydration, have led to continuing research into membranes that have good proton conductivity at elevated temperatures above 120 °C and under low humidity conditions. Such membranes have the potential to avoid catalyst poisoning, simplify fuel cell design and reduce the cost of fuel cells. Hydrocarbon-based membranes are being developed as alternatives to PFSA membranes, but concerns about chemical and mechanical stability and durability remain. Novel anhydrous membranes based on polymer gels infused with protic ionic liquids have also been recently proposed, but considerable fundamental research is needed to understand proton transport in novel membranes and evaluate durability under fuel cell operating conditions. In order to advance this promising technology, it is essential to rationally design the next generation

  16. Nanosecond Lipid Dynamics in Membranes Containing Cholesterol

    SciTech Connect

    Armstrong, Clare L; Haeussler, Wolfgang; Seydel, Tilo; Katsaras, John; Rheinstadter, Maikel C

    2014-01-01

    Lipid dynamics in the cholesterol-rich (40 mol%) liquid-ordered (lo) phase of dimyristoylphosphatidylcholine membranes were studied using neutron spin-echo and neutron backscattering. Recent theoretical and experimental evidence supports the notion of the liquid-ordered phase in phospholipid membranes as a locally structured liquid, with small ordered domains of a highly dynamic nature in equilibrium with a disordered matrix [S. Meinhardt, R. L. C. Vink and F. Schmid, Proc. Natl. Acad. Sci. U. S. A., 2013, 110(12), 4476 4481, C. L. Armstrong et al., PLoS One, 2013, 8(6), e66162]. This local structure was found to have a pronounced impact on the membranes' dynamical properties. We found that the long-wavelength dynamics in the liquid-ordered phase, associated with the elastic properties of the membranes, were faster by two orders of magnitude as compared to the liquid disordered phase. At the same time, collective nanoscale diffusion was significantly slower. The presence of a soft-mode (a slowing down) in the longwavelength dispersion relationship suggests an upper size limit for the ordered lipid domain of ~220 A. Moreover, from the relaxation rate of the collective lipid diffusion of lipid lipid distances, the lifetime of these domains was estimated to be about 100 nanoseconds.

  17. Method for treating liquid wastes

    DOEpatents

    Katti, K.V.; Volkert, W.A.; Singh, P.; Ketring, A.R.

    1995-12-26

    The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering {sup 99}Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of {sup 99}TcO{sub 4}{sup {minus}} from aqueous solutions into organic solvents or mixed organic/polar media, extraction of {sup 99}Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester {sup 99}Tc from those liquids. 6 figs.

  18. Method for treating liquid wastes

    DOEpatents

    Katti, Kattesh V.; Volkert, Wynn A.; Singh, Prahlad; Ketring, Alan R.

    1995-01-01

    The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering .sup.99 Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of .sup.99 TcO.sub.4.sup.- from aqueous solutions into organic solvents or mixed organic/polar media, extraction of .sup.99 Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester .sup.99 Tc from those liquids.

  19. Enhanced performance of PVDF nanocomposite membrane by nanofiber coating: A membrane for sustainable desalination through MD.

    PubMed

    Efome, Johnson E; Rana, Dipak; Matsuura, Takeshi; Lan, Christopher Q

    2016-02-01

    Membrane distillation (MD) is a promising separation technique capable of being used in the desalination of marine and brackish water. Poly(vinylidene fluoride) (PVDF) flat sheet nano-composite membranes were surface modified by coating with electro-spun PVDF nano-fibres to increase the surface hydrophobicity. For this purpose, the nano-composite membrane containing 7 wt.% superhydrophobic SiO2 nano-particles, which showed the highest flux in our previous work, was first subjected to pore size augmentation by increasing the concentration of the pore forming agent (Di-ionized water). Then, the prepared flat sheet membranes were subjected to nanofibres coating by electro-spinning. The uncoated and coated composite fabricated membranes were characterized using contact angle, liquid entry pressure of water, and scanning electron microscopy. The membranes were further tested for 6 h desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD), with a 3.5 wt.% synthetic NaClaq as the feed. In DCMD the feed liquid and permeate side temperature were maintained at 27.5 °C and 15 °C, respectively. For VMD, the feed liquid temperature was 27 °C and a vacuum of 94.8 kPa was applied on the permeate side. The maximum permeate flux achieved was 3.2 kg/m(2).h for VMD and 6.5 kg/m(2).h for DCMD. The salt rejection obtained was higher than 99.98%. The coated membranes showed a more stable flux than the uncoated membranes indicating that the double layered membranes have great potential in solving the pore wetting problem in MD. PMID:26630042

  20. Enhanced performance of PVDF nanocomposite membrane by nanofiber coating: A membrane for sustainable desalination through MD.

    PubMed

    Efome, Johnson E; Rana, Dipak; Matsuura, Takeshi; Lan, Christopher Q

    2016-02-01

    Membrane distillation (MD) is a promising separation technique capable of being used in the desalination of marine and brackish water. Poly(vinylidene fluoride) (PVDF) flat sheet nano-composite membranes were surface modified by coating with electro-spun PVDF nano-fibres to increase the surface hydrophobicity. For this purpose, the nano-composite membrane containing 7 wt.% superhydrophobic SiO2 nano-particles, which showed the highest flux in our previous work, was first subjected to pore size augmentation by increasing the concentration of the pore forming agent (Di-ionized water). Then, the prepared flat sheet membranes were subjected to nanofibres coating by electro-spinning. The uncoated and coated composite fabricated membranes were characterized using contact angle, liquid entry pressure of water, and scanning electron microscopy. The membranes were further tested for 6 h desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD), with a 3.5 wt.% synthetic NaClaq as the feed. In DCMD the feed liquid and permeate side temperature were maintained at 27.5 °C and 15 °C, respectively. For VMD, the feed liquid temperature was 27 °C and a vacuum of 94.8 kPa was applied on the permeate side. The maximum permeate flux achieved was 3.2 kg/m(2).h for VMD and 6.5 kg/m(2).h for DCMD. The salt rejection obtained was higher than 99.98%. The coated membranes showed a more stable flux than the uncoated membranes indicating that the double layered membranes have great potential in solving the pore wetting problem in MD.

  1. Omniphobic Membrane for Robust Membrane Distillation

    SciTech Connect

    Lin, SH; Nejati, S; Boo, C; Hu, YX; Osuji, CO; Ehmelech, M

    2014-11-01

    In this work, we fabricate an omniphobic microporous membrane for membrane distillation (MD) by modifying a hydrophilic glass fiber membrane with silica nanoparticles followed by surface fluorination and polymer coating. The modified glass fiber membrane exhibits an anti-wetting property not only against water but also against low surface tension organic solvents that easily wet a hydrophobic polytetrafluoroethylene (PTFE) membrane that is commonly used in MD applications. By comparing the performance of the PTFE and omniphobic membranes in direct contact MD experiments in the presence of a surfactant (sodium dodecyl sulfate, SDS), we show that SDS wets the hydrophobic PTFE membrane but not the omniphobic membrane. Our results suggest that omniphobic membranes are critical for MD applications with feed waters containing surface active species, such as oil and gas produced water, to prevent membrane pore wetting.

  2. Geometry of membrane fission.

    PubMed

    Frolov, Vadim A; Escalada, Artur; Akimov, Sergey A; Shnyrova, Anna V

    2015-01-01

    Cellular membranes define the functional geometry of intracellular space. Formation of new membrane compartments and maintenance of complex organelles require division and disconnection of cellular membranes, a process termed membrane fission. Peripheral membrane proteins generally control membrane remodeling during fission. Local membrane stresses, reflecting molecular geometry of membrane-interacting parts of these proteins, sum up to produce the key membrane geometries of fission: the saddle-shaped neck and hour-glass hemifission intermediate. Here, we review the fundamental principles behind the translation of molecular geometry into membrane shape and topology during fission. We emphasize the central role the membrane insertion of specialized protein domains plays in orchestrating fission in vitro and in cells. We further compare individual to synergistic action of the membrane insertion during fission mediated by individual protein species, proteins complexes or membrane domains. Finally, we describe how local geometry of fission intermediates defines the functional design of the protein complexes catalyzing fission of cellular membranes. PMID:25062896

  3. Ionomer-Membrane Water Processing Apparatus

    NASA Technical Reports Server (NTRS)

    MacCallum, Taber K. (Inventor); Kelsey, Laura (Inventor)

    2016-01-01

    This disclosure provides water processing apparatuses, systems, and methods for recovering water from wastewater such as urine. The water processing apparatuses, systems, and methods can utilize membrane technology for extracting purified water in a single step. A containment unit can include an ionomer membrane, such as Nafion(Registered Trademark), over a hydrophobic microporous membrane, such as polytetrafluoroethylene (PTFE). The containment unit can be filled with wastewater, and the hydrophobic microporous membrane can be impermeable to liquids and solids of the wastewater but permeable to gases and vapors of the wastewater, and the ionomer membrane can be permeable to water vapor but impermeable to one or more contaminants of the gases and vapors. The containment unit can be exposed to a dry purge gas to maintain a water vapor partial pressure differential to drive permeation of the water vapor, and the water vapor can be collected and processed into potable water.

  4. Anion permselective membrane

    NASA Technical Reports Server (NTRS)

    Hodgdon, R. B.; Waite, W. A.

    1980-01-01

    The efforts on the synthesis of polymer anion redox membranes were mainly concentrated in two areas, membrane development and membrane fabrication. Membrane development covered the preparation and evaluation of experimental membranes systems with improved resistance stability and/or lower permeability. Membrane fabrication covered the laboratory scale production of prime candidate membranes in quantities of up to two hundred and sizes up to 18 inches x 18 inches (46 cm x 46 cm). These small (10 in x 11 in) and medium sized membranes were mainly for assembly into multicell units. Improvements in processing procedures and techniques for preparing such membrane sets lifted yields to over 90 percent.

  5. Membranes for corrosive oxidations. Final CRADA report.

    SciTech Connect

    Snyder, S. W.; Energy Systems

    2010-02-01

    drawbacks, particularly in the extraction phase. One general disadvantage of this technology is that hydrogen peroxide must be produced at large centralized plants where it is concentrated to 70% by distillation and transported to the users plant sites where it is diluted before use. Advanced membranes have the potential to enable more efficient, economic, and safe manufacture of hydrogen peroxide. Advanced membrane technology would allow filtration-based separation to replace the difficult liquid-liquid extraction based separation step of the hydrogen peroxide process. This would make it possible for hydrogen peroxide to be produced on-site in mini-plants at 30% concentration and used at the same plant location without distillation and transportation. As a result, production could become more cost-effective, safe and energy efficient.

  6. LIQUID-LIQUID EXTRACTION COLUMNS

    DOEpatents

    Thornton, J.D.

    1957-12-31

    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  7. FUNDAMENTALS AND APPLICATIONS OF PERVAPORATION THROUGH ZEOLITE MEMBRANES

    EPA Science Inventory

    Zeolite membranes are well suited for separating liquid-phase mixtures by pervaporation because of their molecular-sized pores and their hydrophilic/hydrophobic nature, and the first commercial application of zeolite membranes has been for dehydrating organics [1]. Because of ...

  8. Broadband electrostatic acoustic transducer for ultrasonic measurements in liquids.

    PubMed

    Cantrell, J H; Heyman, J S; Yost, W T; Torbett, M A; Breazeale, M A

    1979-01-01

    A broadband capacitive electrostatic acoustic transducer (ESAT) has been developed for use in a liquid environment at megahertz frequencies. The ESAT basically consists of a thin conductive membrane stretched over a metallic housing. The membrane functions as the ground plate of a parallel plate capacitor, the other plate being a dc biased electrode recessed approximately 10 mum from the electrically grounded membrane. An ultrasonic wave incident on the membrane varies the membrane-electrode gap spacing and generates an electrical signal proportional to the wave amplitude. The entire assembly is sealed for immersion in a liquid environment. Calibration of the ESAT with incident ultrasonic waves of constant displacement amplitude from 1 to 15 MHz reveals a decrease in signal response with increasing frequency independent of membrane tension. The use of the ESAT as a broadband ultrasonic transducer in liquids with a predictable frequency response is promising.

  9. Membrane Systems in Cyanobacteria

    SciTech Connect

    Liberton, Michelle L.; Pakrasi, Himadri B.

    2008-01-01

    Cyanobacteria are photosynthetic prokaryotes with highly differentiated membrane systems. In addition to a Gram-negative-type cell envelope with plasma membrane and outer membrane separated by a periplasmic space, cyanobacteria have an internal system of thylakoid membranes where the fully functional electron transfer chains of photosynthesis and respiration reside. The presence of different membrane systems lends these cells a unique complexity among bacteria. Cyanobacteria must be able to reorganize the membranes, synthesize new membrane lipids, and properly target proteins to the correct membrane system. The outer membrane, plasma membrane, and thylakoid membranes each have specialized roles in the cyanobacterial cell. Understanding the organization, functionality, protein composition and dynamics of the membrane systems remains a great challenge in cyanobacterial cell biology.

  10. Thermo-induced vesicular dynamics of membranes containing cholesterol derivatives.

    PubMed

    Yoda, Tsuyoshi; Vestergaard, Mun'delanji C; Hamada, Tsutomu; Le, Phuc Thi Minh; Takagi, Masahiro

    2012-08-01

    Membrane structural organization is an intrinsic property of a cell membrane. Any changes in lipid composition, and/or any stimuli that affect molecular packing induce structural re-organization. It membrane dynamics provide a means by which changes in structure organization can be determined, upon a change in the membrane internal or external environment. Here, we report on the effect of thermo-stress on membranes containing cholesterol liquid crystal (LC) compounds cholesterol benzoate (BENZO) and oxidized cholesterols. We have (1) revealed that lipid vesicles containing this artificial cholesterol derivative (BENZO) is thermo-responsive, and that this thermo-sensitivity is significantly similar to naturally oxy-cholesterols (2) elucidated the mechanism behind the membrane perturbation. Using Langmuir monolayer experiments, we have demonstrated that membrane perturbation was due to an increase in the molecular surface area, (3) discussed the similarities between cholesterol benzoate in the cholesterol LC state and in lipid bilayer membranes. Last, (4) drawing from previously reported findings, our new data on membrane dynamics, and the discussion above, we propose that artificial cholesterol derivatives such as BENZO, open new possibilities for controlled and tailored design using model membrane systems. Examples could include the development of membrane technology and provide a trigger for progress in thermo-tropical liquid crystal engineering.

  11. Development of taste sensing system using inorganic membrane

    NASA Astrophysics Data System (ADS)

    Kojima, Yohichiro; Hasegawa, Yuki

    2011-09-01

    We developed a novel taste sensor for liquid and verified its effectiveness using coffee. We fabricated an inorganic metal oxide membrane liquid sensor using the laser ablation method. The sensor shows a sufficient sensitivity for electrolyte solutions, while it shows a relatively low response for non-electrolyte solutions. We differentiated and identified five brands of commercially available coffee using the sensor.

  12. Electro membrane extraction using sorbent filled porous membrane bag.

    PubMed

    Naing, Nyi Nyi; Li, Sam Fong Yau; Lee, Hian Kee

    2015-12-01

    Electro membrane extraction-solid-liquid phase microextraction (EME-SLPME) was developed for the first time to determine phenolic contaminants in water. The extraction system consisted of a solid/liquid interface that permitted a three-phase microextraction approach involving an aqueous sample (donor phase): an organic solvent-sorbent within a membrane bag, and an organic solvent (extractant phase), operated in a direct immersion sampling system. The sorbent, reduced graphene oxide/polyvinyl alcohol, synthesized using graphene oxide and polyvinyl alcohol by dispersing the graphene oxide in polyvinyl alcohol and chemically reducing it in aqueous solution. The prepared sorbent was dispersed in 1-octanol and the solution was immobilized by sonication in the membrane bag wall pores which was in contact with the aqueous donor solution and organic extractant solvent (1-octanol) in the main bag itself. The analytes were transported by application of an electrical potential difference of 100V across the sorbent/solvent phase from the aqueous sample into the organic extractant phase in the membrane bag. After extraction and derivatization, gas chromatography-mass spectrometry was used to determine the derivatized analytes. This proposed EME-LSPME procedure provided high extraction efficiency with relative recoveries up to 99.6%. A linearity range of between 0.05 and 100μgL(-1) with corresponding coefficients of determination (r(2)) of between 0.987 and 0.996 were obtained. The limits of detection were in the range of between 0.003 and 0.053μgL(-1). This proposed method was successfully applied to the extraction of phenolic contaminants from water sample. PMID:26530143

  13. Membrane behavior of clay liner materials

    NASA Astrophysics Data System (ADS)

    Kang, Jong Beom

    Membrane behavior represents the ability of porous media to restrict the migration of solutes, leading to the existence of chemico-osmosis, or the flow of liquid in response to a chemical concentration gradient. Membrane behavior is an important consideration with respect to clay soils with small pores and interactive electric diffuse double layers associated with individual particles, such as bentonite. The results of recent studies indicate the existence of membrane behavior in bentonite-based hydraulic barriers used in waste containment applications. Thus, measurement of the existence and magnitude of membrane behavior in such clay soils is becoming increasingly important. Accordingly, this research focused on evaluating the existence and magnitude of membrane behavior for three clay-based materials that typically are considered for use as liners for waste containment applications, such as landfills. The three clay-based liner materials included a commercially available geosynthetic clay liner (GCL) consisting of sodium bentonite sandwiched between two geotextiles, a compacted natural clay known locally as Nelson Farm Clay, and compacted NFC amended with 5% (dry wt.) of a sodium bentonite. The study also included the development and evaluation of a new flexible-wall cell for clay membrane testing that was used subsequently to measure the membrane behaviors of the three clay liner materials. The consolidation behavior of the GCL under isotropic states of stress also was evaluated as a preliminary step in the determination of the membrane behavior of the GCL under different effective consolidation stresses.

  14. Energetics of water permeation through fullerene membrane

    PubMed Central

    Isobe, Hiroyuki; Homma, Tatsuya; Nakamura, Eiichi

    2007-01-01

    Lipid bilayer membranes are important as fundamental structures in biology and possess characteristic water-permeability, stability, and mechanical properties. Water permeation through a lipid bilayer membrane occurs readily, and more readily at higher temperature, which is largely due to an enthalpy cost of the liquid-to-gas phase transition of water. A fullerene bilayer membrane formed by dissolution of a water-soluble fullerene, Ph5C60K, has now been shown to possess properties entirely different from those of the lipid membranes. The fullerene membrane is several orders of magnitude less permeable to water than a lipid membrane, and the permeability decreases at higher temperature. Water permeation is burdened by a very large entropy loss and may be favored slightly by an enthalpy gain, which is contrary to the energetics observed for the lipid membrane. We ascribe this energetics to favorable interactions of water molecules to the surface of the fullerene molecules as they pass through the clefts of the rigid fullerene bilayer. The findings provide possibilities of membrane design in science and technology. PMID:17846427

  15. Vacuum membrane distillation: Experiments and modeling

    SciTech Connect

    Bandini, S.; Saavedra, A.; Sarti, G.C.

    1997-02-01

    Vacuum membrane distillation is a membrane-based separation process considered here to remove volatile organic compounds from aqueous streams. Microporous hydrophobic membranes are used to separate the aqueous stream from a gas phase kept under vacuum. The evaporation of the liquid stream takes place on one side of the membrane, and mass transfer occurs through the vapor phase inside the membrane. The role of operative conditions on the process performance is widely investigated in the case of dilute binary aqueous mixtures containing acetone, ethanol, isopropanol, ethylacetate, methylacetate, or methylterbutyl ether. Temperature, composition, flow rate of the liquid feed, and pressure downstream the membrane are the main operative variables. Among these, the vacuum-side pressure is the major design factor since it greatly affects the separation efficiency. A mathematical model description of the process is developed, and the results are compared with the experiments. The model is finally used to predict the best operative conditions in which the process can work for the case of benzene removal from waste waters.

  16. Molecular dynamic simulation methods for anisotropic liquids.

    PubMed

    Aoki, Keiko M; Yoneya, Makoto; Yokoyama, Hiroshi

    2004-03-22

    Methods of molecular dynamics simulations for anisotropic molecules are presented. The new methods, with an anisotropic factor in the cell dynamics, dramatically reduce the artifacts related to cell shapes and overcome the difficulties of simulating anisotropic molecules under constant hydrostatic pressure or constant volume. The methods are especially effective for anisotropic liquids, such as smectic liquid crystals and membranes, of which the stacks of layers are compressible (elastic in direction perpendicular to the layers) while the layer itself is liquid and only elastic under uniform compressive force. The methods can also be used for crystals and isotropic liquids as well.

  17. Use of fluorescence-activated flow cytometry to determine membrane lipid peroxidation during hypothermic liquid storage and freeze-thawing of viable boar sperm loaded with 4, 4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid.

    PubMed

    Guthrie, H D; Welch, G R

    2007-06-01

    Part of the reduction in boar sperm motility and fertility associated with hypothermic liquid storage and cryopreservation may be due to membrane lipid peroxidation. Lipid peroxidation was monitored by the shift from red to green fluorescence emission of the lipophilic probe 4, 4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid, C(11)BODIPY(581/591) (BODIPY), as measured by fluorescence-activated flow cytometry in live sperm (negative for propidium iodide). Experiments were conducted with Percoll-washed sperm to determine the specificity of BODIPY oxidation in the presence of different reactive oxygen species generators and metal chelators. Compared with no FeSO(4) and Na ascorbate, the combination of FeSO(4) and Na ascorbate (FeAc) increased (P < 0.01) the percentage of sperm containing oxidized BODIPY from 70% and increased (P < 0.05) BOD-IPY fluorescence intensity/cell by 5- to 10-fold after a 30-min incubation. Motility was depressed (P < 0.05) after exposure to FeAc, but viability was not affected. Of the reactive oxygen species generators tested, BODIPY oxidation was specific for FeAc, because menadione and H(2)O(2) had little or no effect. The oxidization of hydroethidine to ethidium was specific for menadione and H(2)O(2); FeAc had no effect. The presence of the metal chelators EDTA or deferoxamine mesylate at 3 and 9 muM inhibited FeAc-induced BODIPY oxidation and maintained motility. Experiments were conducted to determine the effect of liquid storage at 17 degrees C for 1 and 5 d and the effect of freeze-thawing on basal and FeAc-induced BODIPY oxidation. Basal BODIPY oxidation (no FeAc) was low in liquid stored and thawed viable sperm (1.3 and 3.4%, respectively). Although the incidence of basal or spontaneous membrane lipid peroxidation was low during liquid storage and after freeze-thawing, viable boar sperm were susceptible to FeAc-induced lipid peroxidation. PMID:17296775

  18. Liquid Ventilation

    PubMed Central

    Tawfic, Qutaiba A.; Kausalya, Rajini

    2011-01-01

    Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. PMID:22043370

  19. LIQUID TARGET

    DOEpatents

    Martin, M.D.; Salsig, W.W. Jr.

    1959-01-13

    A liquid handling apparatus is presented for a liquid material which is to be irradiated. The apparatus consists essentially of a reservoir for the liquid, a target element, a drain tank and a drain lock chamber. The target is in the form of a looped tube, the upper end of which is adapted to be disposed in a beam of atomic particles. The lower end of the target tube is in communication with the liquid in the reservoir and a means is provided to continuously circulate the liquid material to be irradiated through the target tube. Means to heat the reservoir tank is provided in the event that a metal is to be used as the target material. The apparatus is provided with suitable valves and shielding to provide maximum safety in operation.

  20. Direct deposit of catalyst on the membrane of direct feed fuel cells

    NASA Technical Reports Server (NTRS)

    Chun, William (Inventor); Narayanan, Sekharipuram R. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Valdez, Thomas I. (Inventor); Linke, Juergen (Inventor)

    2001-01-01

    An improved direct liquid-feed fuel cell having a solid membrane electrolyte for electrochemical reactions of an organic fuel. Catalyst utilization and catalyst/membrane interface improvements are disclosed. Specifically, the catalyst layer is applied directly onto the membrane electrolyte.