Organic fluid permeation through fluoropolymer membranes

DOEpatents

Nemser, Stuart M.; Kosaraju, Praveen; Bowser, John

2015-07-14

Separation of the components of liquid mixtures is achieved by contacting a liquid mixture with a nonporous membrane having a fluoropolymer selectively permeable layer and imposing a pressure gradient across the membrane from feed side to permeate side. Unusually high transmembrane flux is obtained when the membrane is subjected to one or more process conditions prior to separation. These include (a) leaving some residual amount of membrane casting solvent in the membrane, and (b) contacting the membrane with a component of the mixture to be separated for a duration effective to saturate the membrane with the component.

Superhydrophobic and superhydrophilic surface-enhanced separation performance of porous inorganic membranes for biomass-to-biofuel conversion applications

DOE PAGES

Hu, Michael Z.; Engtrakul, Chaiwat; Bischoff, Brian L.; ...

2016-11-14

A new class of inorganic-based membranes, i.e., High-Performance Architectured Surface Selective (HiPAS) membranes, is introduced to provide high perm-selective flux by exploiting unique separation mechanisms induced by superhydrophobic or superhydrophilic surface interactions and confined capillary condensation in enlarged membrane pores (~8 nm). The super-hydro-tunable HiPAS membranes were originally developed for the purpose of bio-oil/biofuel processing to achieve selective separations at higher flux relative to size selective porous membranes (e.g., inorganic zeolite-based membranes) and better high-temperature tolerance than polymer membranes (>250 C) for hot vapor processing. Due to surface-enhanced separation selectivity, HiPAS membranes can thus possibly enable larger pores to facilitatemore » large-flux separations by increasing from sub-nanometer pores to mesopores (2-50 nm) for vapor phase or micron-scale pores for liquid phase separations. In this paper, we describe an innovative membrane concept and a materials synthesis strategy to fabricate HiPAS membranes, and demonstrate selective permeation in both vapor- and liquid-phase applications. High permeability and selectivity were demonstrated using surrogate mixtures, such as ethanol-water, toluene-water, and toluene-phenol-water. The overall membrane evaluation results show promise for the future processing of biomass pyrolysis and upgraded product vapors and condensed liquid bio-oil intermediates.« less

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.

Preparation of Interconnected Biomimetic Poly(vinylidene fluoride-co-chlorotrifluoroethylene) Hydrophobic Membrane by Tuning the Two-Stage Phase Inversion Process.

PubMed

Zheng, Libing; Wang, Jun; Wu, Zhenjun; Li, Jie; Zhang, Yong; Yang, Min; Wei, Yuansong

2016-11-30

A facile strategy was applied for poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) hydrophobic membrane preparation by tuning the two-stage phase inversion process. The exposure stage was found to benefit the solid-liquid demixing process (gelation/crystallization) induced by the solvent evaporation and the subsequent phase inversion induced by immersion benefit the liquid-liquid demixing. It was confirmed that the electrospun nanostructure-like biomimetic surface and interconnected pore structure can be expected by controlling the exposure duration, and 300 s was considered as the inflection point of exposure duration for PVDF-CTFE membrane through which a tremendous variation would show. The micro/nanohierarchical structure in the membrane surface owing to the crystallization of PVDF-CTFE copolymer was responsible for the improvement of membrane roughness and hydrophobicity. Meanwhile, the interconnected pore structure in both the surface and the cross-section, which were formed because of the crystallization process, offers more mass transfer passages and enhances the permeate flux. The membrane then showed excellent MD performance with high permeate flux, high salt rejection, and relatively high stability during a 48 h continuous DCMD operation, according to the morphology, pore structure, and properties, which can be a substitute for hydrophobic membrane application.

Application of a nanofibrous composite membrane to the fertilizer-driven forward osmosis process for irrigation water use.

PubMed

An, Hee-Kyung; Lee, Chang-Gu; Park, Seong-Jik

2017-11-01

In this study, we fabricated a nanofibrous composite (NFC) membrane as a substrate to produce forward osmosis (FO) membranes, and we also assessed the use of liquid fertilizer as a draw solution for the FO process in order to produce agricultural irrigation water. Commercial cellulose triacetate (CTA) and thin-film composite (TFC) FO membranes were included in this study. Under FO tests, the NFC, CTA, and TFC membranes achieved initial osmotic water flux values of 35.31, 6.85, and 3.31 L/m 2 ·h and final osmotic water flux values of 12.62, 6.31, and 3.85 L/m 2  h, respectively. The reason for the high osmotic water flux of the NFC membrane is because its nanofiber layer has low tortuosity, high porosity, and a low thickness, resulting in a reduction in the internal concentration polarization phenomenon. When liquid fertilizer was used as the draw solution, the water flux values in the FO experiments for the NFC, CTA, and TFC membranes were 15.54, 5.46, and 2.54 L/m 2  h. Finally, our results revealed that the FO process using liquid fertilizer as a draw solution can be applied to produce agricultural irrigation water from brackish water and the newly fabricated NFC membrane can be applied to the FO process.

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.

Process for removing sulfate anions from waste water

DOEpatents

Nilsen, David N.; Galvan, Gloria J.; Hundley, Gary L.; Wright, John B.

1997-01-01

A liquid emulsion membrane process for removing sulfate anions from waste water is disclosed. The liquid emulsion membrane process includes the steps of: (a) providing a liquid emulsion formed from an aqueous strip solution and an organic phase that contains an extractant capable of removing sulfate anions from waste water; (b) dispersing the liquid emulsion in globule form into a quantity of waste water containing sulfate anions to allow the organic phase in each globule of the emulsion to extract and absorb sulfate anions from the waste water and (c) separating the emulsion including its organic phase and absorbed sulfate anions from the waste water to provide waste water containing substantially no sulfate anions.

Ozone mass transfer behaviors on physical and chemical absorption for hollow fiber membrane contactors.

PubMed

Zhang, Yong; Li, Kuiling; Wang, Jun; Hou, Deyin; Liu, Huijuan

2017-09-01

To understand the mass transfer behaviors in hollow fiber membrane contactors, ozone fluxes affected by various conditions and membranes were investigated. For physical absorption, mass transfer rate increased with liquid velocity and the ozone concentration in the gas. Gas flow rate was little affected when the velocity was larger than the critical value, which was 6.1 × 10 -3 m/s in this study. For chemical absorption, the flux was determined by the reaction rate between ozone and the absorbent. Therefore, concentration, species, and pH affected the mass transfer process markedly. For different absorbents, the order of mass transfer rate was the same as the reaction rate constant, which was phenol, sodium nitrite, hydrogen peroxide, and oxalate. Five hydrophobic membranes with various properties were employed and the mass transfer behavior can be described by the Graetz-Lévèque equation for the physical absorption process. The results showed the process was controlled by liquid film and the gas phase conditions, and membrane properties did not affect the ozone flux. For the chemical absorption, gas film, membrane and liquid film affected the mass transfer together, and none of them were negligible.

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.

Topologically Diverse Human Membrane Proteins Partition to Liquid-Disordered Domains in Phase-Separated Lipid Vesicles.

PubMed

Schlebach, Jonathan P; Barrett, Paul J; Day, Charles A; Kim, Ji Hun; Kenworthy, Anne K; Sanders, Charles R

2016-02-23

The integration of membrane proteins into "lipid raft" membrane domains influences many biochemical processes. The intrinsic structural properties of membrane proteins are thought to mediate their partitioning between membrane domains. However, whether membrane topology influences the targeting of proteins to rafts remains unclear. To address this question, we examined the domain preference of three putative raft-associated membrane proteins with widely different topologies: human caveolin-3, C99 (the 99 residue C-terminal domain of the amyloid precursor protein), and peripheral myelin protein 22. We find that each of these proteins are excluded from the ordered domains of giant unilamellar vesicles containing coexisting liquid-ordered and liquid-disordered phases. Thus, the intrinsic structural properties of these three topologically distinct disease-linked proteins are insufficient to confer affinity for synthetic raft-like domains.

Membrane contactor assisted extraction/reaction process employing ionic liquids

DOEpatents

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

2012-02-07

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

Application of mixed based membrane technology from component materials bintaro, zeolite and bentonite to reduction of songket waste liquid cloth

NASA Astrophysics Data System (ADS)

Dahlan, Muhammad Hatta; Saleh, Abdullah; Asip, Faisol; Makmun, Akbar; Defi

2017-11-01

Application of membrane technology based on clay mixture, Activated Carbon from Bintaro, Zeolite and Bentonit to process the waste water of Songket cloth is Palembang traditionally cloth. The applied research is into the superior field of industrial and household waste processing with membrane ceramic technology. The objective of this research is to design the liquid waste separation tool of jumputan cloth using better and simpler ceramic membrane so that it can help the artisans of Palembang songket or songket in processing the waste in accordance with the standard of environmental quality standard (BML) and Pergub Sumsel no. 16 in 2005. The specific target to be achieved can decrease the waste of cloth jumputan in accordance with applicable environmental quality standards the method used in achieving the objectives of this study using 2 processes namely the adsorption process using activated carbon and the separation process using a ceramic membrane based on the composition of the mixture. The activated carbon from bintaro seeds is expected to decrease the concentration of liquid waste of Songket cloth. Bintaro seeds are non-edible fruits where the composition contains organic ingredients that can absorb because contains dyes and filler metals. The process of membranization in the processing is expected to decrease the concentration of waste better and clear water that can be used as recycled water for household use. With the composition of a mixture of clay-based materials: zeolite, bentonit, activated carbon from bintaro seeds are expected Find the solution and get the novelty value in the form of patent in this research

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.

Recovery of Ni Metal from Spent Catalyst with Emulsion Liquid Membrane Using Cyanex 272 as Extractant

NASA Astrophysics Data System (ADS)

Yuliusman; Huda, M.; Ramadhan, I. T.; Farry, A. R.; Wulandari, P. T.; Alfia, R.

2018-03-01

In this study was conducted to recover nickel metal from spent nickel catalyst resulting from hydrotreating process in petroleum industry. The nickel extraction study with the emulsion liquid membrane using Cyanex 272 as an extractant to extract and separate nickel from the feed phase solution. Feed phase solution was preapred from spent catalyst using sulphuric acid. Liquid membrane consists of a kerosene as diluent, a Span 80 as surfactant, a Cyanex 272 as carrier and sulphuric acid solutions have been used as the stripping solution. The important parameters governing the permeation of nickel and their effect on the separation process have been studied. These parameters are surfactant concentration, extractant concentration feed phase pH. The optimum conditions of the emulsion membrane making process is using 0.06 M Cyanex 272, 8% w/v SPAN 80, 0.05 M H2SO4, internal phase extractant / phase volume ratio: 1/1, and stirring speed 1150 rpm for 60 Minute that can produce emulsion membrane with stability level above 90% after 4 hours. In the extraction process with optimum condition pH 6 for feed phase, ratio of phase emulsion/phase of feed: 1/2, and stirring speed 175 rpm for 15 minutes with result 81.51% nickel was extracted.

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.

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.

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.

Non-newtonian enhancement of both stability and permeability of liquid membranes for detoxifying wastewater. Report for 1 July 1991-30 September 1993

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skelland, A.H.P.

1995-06-01

Emulsion liquid membrane processes constitute an emerging separations technology with widespread applications, including wastewater purification. However, they currently remain excessively vulnerable to one of more of four major problems. The difficulties lie in developing liquid membranes that combine high levels of both stability and permeability with acceptably low levels of swelling and ease of subsequent demulsification for membrane and solute recovery. This work provides a new technique for simultaneously overcoming the first three problems, while identifying physical indications that the proposed solution may have little adverse effect upon the fourth problem (demulsification) and may even alleviate it. The responsiveness ofmore » both aliphatic and aromatic membranes to the new technique has been demonstrated.« less

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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Process for photosynthetically splitting water

DOEpatents

Greenbaum, Elias

1984-01-01

The invention is an improved process for producing gaseous hydrogen and oxygen from water. The process is conducted in a photolytic reactor which contains a water-suspension of a photoactive material containing a hydrogen-liberating catalyst. The reactor also includes a volume for receiving gaseous hydrogen and oxygen evolved from the liquid phase. To avoid oxygen-inactivation of the catalyst, the reactor is evacuated continuously by an external pump which circulates the evolved gases through means for selectively recovering hydrogen therefrom. The pump also cools the reactor by evaporating water from the liquid phase. Preferably, product recovery is effected by selectively diffusing the hydrogen through a heated semipermeable membrane, while maintaining across the membrane a magnetic field gradient which biases the oxygen away from the heated membrane. This promotes separation, minimizes the back-reaction of hydrogen and oxygen, and protects the membrane.

Development of supported liquid membrane techniques for the monitoring of trace levels of organic pollutants in wastewaters and water purification systems

NASA Astrophysics Data System (ADS)

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

The supported liquid membrane (SLM) extraction technique has been developed and successfully used for the monitoring of trace quantities of ionisable organic contaminants, including 17β-estradiol and its metabolites, testosterones and their methyl ester derivatives, benzimidazole anthelmintic antibiotics and sulphonamides in aquatic systems. A number of parameters which control the mass transfer in the supported liquid membrane extraction process such as donor and acceptor pH, extraction time and the type of organic liquid membrane were optimised to enhance the efficiency of the liquid membrane in the removal of these compounds. The method developed gave very low detection limits (0.3 ng/l to 2.4 ng/l for 17β-estradiol and its metabolites; between 1 μg/l and 20 μg/l for sulphonamides; and between 0.1 ng/l and 10 ng/l for benzimidazole anthelmintic compounds). The SLM method showed good linearity, reproducibility and repeatability values and is therefore suitable for routine monitoring of such compounds in water and wastewater systems.

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...

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 ...

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...

Combination of Collagen Barrier Membrane with Enamel Matrix Derivative-Liquid Improves Osteoblast Adhesion and Differentiation.

PubMed

Miron, Richard J; Fujioka-Kobayashi, Masako; Buser, Daniel; Zhang, Yufeng; Bosshardt, Dieter D; Sculean, Anton

Collagen barrier membranes were first introduced to regenerative periodontal and oral surgery to prevent fast ingrowing soft tissues (ie, epithelium and connective tissue) into the defect space. More recent attempts have aimed at combining collagen membranes with various biologics/growth factors to speed up the healing process and improve the quality of regenerated tissues. Recently, a new formulation of enamel matrix derivative in a liquid carrier system (Osteogain) has demonstrated improved physico-chemical properties for the adsorption of enamel matrix derivative to facilitate protein adsorption to biomaterials. The aim of this pioneering study was to investigate the use of enamel matrix derivative in a liquid carrier system in combination with collagen barrier membranes for its ability to promote osteoblast cell behavior in vitro. Undifferentiated mouse ST2 stromal bone marrow cells were seeded onto porcine-derived collagen membranes alone (control) or porcine membranes + enamel matrix derivative in a liquid carrier system. Control and enamel matrix derivative-coated membranes were compared for cell recruitment and cell adhesion at 8 hours; cell proliferation at 1, 3, and 5 days; and real-time polymerase chain reaction (PCR) at 3 and 14 days for genes encoding Runx2, collagen1alpha2, alkaline phosphatase, and bone sialoprotein. Furthermore, alizarin red staining was used to investigate mineralization. A significant increase in cell adhesion was observed at 8 hours for barrier membranes coated with enamel matrix derivative in a liquid carrier system, whereas no significant difference could be observed for cell proliferation or cell recruitment. Enamel matrix derivative in a liquid carrier system significantly increased alkaline phosphatase mRNA levels 2.5-fold and collagen1alpha2 levels 1.7-fold at 3 days, as well as bone sialoprotein levels twofold at 14 days postseeding. Furthermore, collagen membranes coated with enamel matrix derivative in a liquid carrier system demonstrated a sixfold increase in alizarin red staining at 14 days when compared with collagen membrane alone. The combination of enamel matrix derivative in a liquid carrier system with a barrier membrane significantly increased cell attachment, differentiation, and mineralization of osteoblasts in vitro. Future animal testing is required to fully characterize the additional benefits of combining enamel matrix derivative in a liquid carrier system with a barrier membrane for guided bone or tissue regeneration.

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.

Study of cyanide wastewater treatment by dispersion supported liquid membrane using trioctylamine and kerosene as liquid membrane.

PubMed

Li, Guo Ping; Xue, Juan Qin; Yu, Li Hua; Liu, Ni Na

2015-01-01

A certain amount of cyanide is present in wastewater of various industrial processes, such as wet extraction of gold, coal processing, electroplating and other industries. In this work, an experimental study regarding transport of cyanide through a dispersion supported liquid membrane was performed. A model was established to describe the reaction and transport of CN(I) in the supported liquid membrane and the mass transfer kinetics equations were deduced. Through mass transfer kinetic equation it was derived that, when the carrier concentration was under certain conditions, there was a linear relationship between the reciprocal of the permeability coefficient of CN(I) (1/Pc) and n-th power of the concentration of H+ (cnH+), and the parameters Δa(δa/da) and Δo(δ0/d0) could be obtained from the slope and intercept of the straight line. Then the diffusion coefficient do and the diffusion layer thickness δo of the phase interface between the feed phase and membrane phase could be calculated. Factors affecting migration of CN(I) were analyzed, and the stable removal rate of CN(I) was more than 90% with carrier concentration (%TOA) of 2%, feed phase pH of 4, initial CN(I) concentration of 30 mg/L, stirring time of 1 hour, volume ratio of membrane solution to NaOH solution of 2:1, strip phase concentration of 2 mol/L. The results showed that the overall mass transfer rate increased first and then decreased with an increase of TOA concentration, organic-to-strip volume ratio, and strip concentration. Furthermore, the transport percentage of CN(I) was increased, the stability of membrane was enhanced, and the lifetime of the membrane was extended.

Ion-selective detection by plasticized poly(vinyl chloride) membrane in glass nanopipette with alternating voltage modulation.

PubMed

Deng, Xiao Long; Takami, Tomohide; Son, Jong Wan; Kang, Eun Ji; Kawai, Tomoji; Park, Bae Ho

2013-08-01

An alternating current (AC) voltage modulation was applied to ion-selective observations with plasticized poly(vinyl chloride) membranes in glass nanopipettes. The liquid confronting the membranes in the nanopipettes, the conditioning process, and AC voltage modulation play important roles in the ion-selective detection. In the AC detection system developed by us, where distilled water was used as the liquid within the nanopipettes, potassium ions were selectively detected in the sample solution of sodium and potassium ions because sodium ions were captured at the membrane containing bis(12-crown-4) ionophores, before the saturation of the ionophores. The membrane lost the selectivity after the saturation. On using sodium chloride as the liquid within the nanopipette, the membrane selectively detected potassium and sodium ions before and after the saturation of ionophores, respectively. The ion-selective detection of our system can be explained by the ion extraction-diffusion-dissolution mechanism through the bis(12-crown-4) ionophores with AC voltage modulation.

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.

Cyclic membrane separation process

DOEpatents

Bowser, John

2004-04-13

A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In one of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the other part, the membrane is inoperative while gas pressure rises in the ullage. Ambient air is charged to the membrane separation unit during the latter part of the cycle.

New porous monolithic membranes based on supported ionic liquid-like phases for oil/water separation and homogenous catalyst immobilisation.

PubMed

Porcar, Raúl; Nuevo, Daniel; García-Verdugo, Eduardo; Lozano, Pedro; Sanchez-Marcano, José; Burguete, M Isabel; Luis, Santiago V

2018-03-07

Porous monolithic advanced functional materials based on supported ionic liquid-like phase (SILLP) systems were used for the preparation of oleophilic and hydrophobic cylindrical membranes and successfully tested as eco-friendly and safe systems for oil/water separation and for the continuous integration of catalytic and separation processes in an aqueous-organic biphasic reaction system.

Pressure Swing Absorption Device and Process for Separating CO{sub 2} from Shifted Syngas and its Capture for Subsequent Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sirkar, Kamalesh; Jie, Xingming; Chau, John

Using the ionic liquid (IL) 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]) as the absorbent on the shell side of a membrane module containing either a porous hydrophobized ceramic tubule or porous hydrophobized polyether ether ketone (PEEK) hollow fiber membranes, studies for CO{sub 2} removal from hot simulated pre-combustion shifted syngas were carried out by a novel pressure swing membrane absorption (PSMAB) process. Helium was used as a surrogate for H{sub 2} in a simulated shifted syngas with CO{sub 2} around 40% (dry gas basis). In this cyclic separation process, the membrane module was used to achieve non-dispersive gas absorption from a high-pressure feedmore » gas (689-1724 kPag; 100-250 psig) at temperatures between 25-1000C into a stationary absorbent liquid on the module shell side during a certain part of the cycle followed by among other cycle steps controlled desorption of the absorbed gases from the liquid in the rest of the cycle. Two product streams were obtained, one He-rich and the other CO{sub 2}-rich. Addition of polyamidoamine (PAMAM) dendrimer of generation 0 to IL [bmim][DCA] improved the system performance at higher temperatures. The solubilities of CO{sub 2} and He were determined in the ionic liquid with or without the dendrimer in solution as well as in the presence or absence of moisture; polyethylene glycol (PEG) 400 was also studied as a replacement for the IL. The solubility selectivity of the ionic liquid containing the dendrimer for CO{sub 2} over helium was considerably larger than that for the pure ionic liquid. The solubility of CO{sub 2} and CO{sub 2}-He solubility selectivity of PEG 400 and a solution of the dendrimer in PEG 400 were higher than the corresponding ones in the IL, [bmim][DCA]. A mathematical model was developed to describe the PSMAB process; a numerical solution of the governing equations described successfully the observed performance of the PSMAB process for the pure ionic liquid-based system.« less

Recovery of high-purity silver directly from dilute effluents by an emulsion liquid membrane-crystallization process.

PubMed

Tang, Bing; Yu, Guojun; Fang, Jianzhang; Shi, Taihong

2010-05-15

An emulsion liquid membrane (ELM)-crystallization process, using hypophosphorous acid as a reducing agent in the internal aqueous phase, has been developed for the purpose of recovering high-purity silver directly from dilute industrial effluents (waste rinse water). After pretreatment with HNO(3), silver in waste rinse water can be reliably recovered with high efficiency through the established process. The main parameters in the process of ELM-crystallization include the concentration of carrier in the membrane phase, the concentration of reducing agent in the internal aqueous phase, and the treatment ratio, which influence the recovery efficiency to various extents and must be controlled carefully. The results indicated that more than 99.5% (wt.) of the silver ions in the external aqueous phase were extracted by the ELM-crystallization process, with an average efficiency of recovery of 99.24% (wt.) and a purity of 99.92% (wt.). The membrane phase can be used repeatedly without loss of the efficiency of recovery. Copyright (c) 2009 Elsevier B.V. All rights reserved.

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

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

PubMed

Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

2017-08-03

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

Water hyacinth cellulose-based membrane for adsorption of liquid waste dyes and chromium

NASA Astrophysics Data System (ADS)

Agtasia Putri, Cintia; Yulianti, Ian; Desianna, Ika; Sholihah, Anisa; Sujarwata

2018-04-01

Water hyacinth (Eichornia crassipes) is a weed in aquatic area whose trunk contains a lot of cellulose. Cellulose contained can be used as dyes adsorbent in a form of composite membrane. This study aims to investigate the capacity of water hyacinth cellulose-based membrane to adsorb dye and Chromium (Cr) contained in liquid. The process of membrane fabrication begins with isolation of water hyacinth cellulose. The isolated cellulose powder was used to make the membrane by mixing it with polyvinyl alcohol-polyethylene glycol (PVA-PEG) with various compositions. The morphology of membrane surface was analyzed using CCD microscope. The analysis using Ultraviolet Visible Spectroscopy (UV-Vis) and Atomic Absorption Spectroscopy (AAS) indicate that the membrane with composition ratio of cellulose: PVA: PEG of 6.5: 2.5: 1 adsorb Cr up to 38.75%.

Adiabatic burst evaporation from bicontinuous nanoporous membranes

PubMed Central

Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk

2015-01-01

Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406

Solid and Liquid Waste Drying Bag

NASA Technical Reports Server (NTRS)

Litwiller, Eric (Inventor); Hogan, John A. (Inventor); Fisher, John W. (Inventor)

2009-01-01

Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.

Investigation of hydrodynamic behaviour of membranes using radiotracer techniques

NASA Astrophysics Data System (ADS)

Miskiewicz, A.; Zakrzewska-Trznadel, G.

2013-05-01

The aim of the work was to study membrane devices using short-lived radioisotopes like Ba-137m and Ga-68 as tracers. These radioisotopes were obtained from radionuclide generators: Cs-137/Ba-137m and Ge-68/Ga-68. The first radionuclide, namely Ba-137m with a half-life of 2.55 minutes was applied as a liquid phase tracer for studying hydrodynamic conditions inside the membrane apparatus. The membrane module with ceramic membranes was tested by using Ba-137m. The experiments showed that this radionuclide with a short half-life is a perfect tracer for liquid phase, whereas Ga-68 with longer half-life equal to 68 minutes was considered as a solid phase (bentonite) tracer. Ga-68 was used to gain more knowledge about the phenomena occurring in the membrane boundary layer. After kinetic studies of isotope adsorption into the carrier material, the growth rate of the deposit layer as well as deposit's thickness on the flat-sheet membrane were studied. The influence of such process parameters like pressure, linear velocity of liquid and feed concentration on formation of the bentonite layer on the membrane surface was studied.

Generalized Boussinesq-Scriven surface fluid model with curvature dissipation for liquid surfaces and membranes.

PubMed

Aguilar Gutierrez, Oscar F; Herrera Valencia, Edtson E; Rey, Alejandro D

2017-10-01

Curvature dissipation is relevant in synthetic and biological processes, from fluctuations in semi-flexible polymer solutions, to buckling of liquid columns, tomembrane cell wall functioning. We present a micromechanical model of curvature dissipation relevant to fluid membranes and liquid surfaces based on a parallel surface parameterization and a stress constitutive equation appropriate for anisotropic fluids and fluid membranes.The derived model, aimed at high curvature and high rate of change of curvature in liquid surfaces and membranes, introduces additional viscous modes not included in the widely used 2D Boussinesq-Scriven rheological constitutive equation for surface fluids.The kinematic tensors that emerge from theparallel surface parameterization are the interfacial rate of deformation and the surface co-rotational Zaremba-Jaumann derivative of the curvature, which are used to classify all possibledissipative planar and non-planar modes. The curvature dissipation function that accounts for bending, torsion and twist rates is derived and analyzed under several constraints, including the important inextensional bending mode.A representative application of the curvature dissipation model to the periodic oscillation in nano-wrinkled outer hair cells show how and why curvature dissipation decreases with frequency, and why the 100kHz frequency range is selected. These results contribute to characterize curvature dissipation in membranes and liquid surfaces. Copyright © 2017 Elsevier Inc. All rights reserved.

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

The recycling or sequestration of carbon dioxide (CO2) from the waste gas of fossil-fuel power plants is widely acknowledged as one of the most realistic strategies for delaying or avoiding the severest environmental, economic, political, and social consequences that will result from global climate change and ocean acidification. For context, in 2013 coal and natural gas power plants accounted for roughly 31% of total U.S. CO2 emissions. Recycling or sequestering this CO2 would reduce U.S. emissions by ca. 1800 million metric tons-easily meeting the U.S.'s currently stated CO2 reduction targets of ca. 17% relative to 2005 levels by 2020. This situation is similar for many developed and developing nations, many of which officially target a 20% reduction relative to 1990 baseline levels by 2020. To make CO2 recycling or sequestration processes technologically and economically viable, the CO2 must first be separated from the rest of the waste gas mixture-which is comprised mostly of nitrogen gas and water (ca. 85%). Of the many potential separation technologies available, membrane technology is particularly attractive due to its low energy operating cost, low maintenance, smaller equipment footprint, and relatively facile retrofit integration with existing power plant designs. From a techno-economic standpoint, the separation of CO2 from flue gas requires membranes that can process extremely high amounts of CO2 over a short time period, a property defined as the membrane "permeance". In contrast, the membrane's CO2/N2 selectivity has only a minor effect on the overall cost of some separation processes once a threshold permeability selectivity of ca. 20 is reached. Given the above criteria, the critical properties when developing membrane materials for postcombustion CO2 separation are CO2 permeability (i.e., the rate of CO2 transport normalized to the material thickness), a reasonable CO2/N2 selectivity (≥20), and the ability to be processed into defect-free thin-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.

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

NASA Astrophysics Data System (ADS)

Zhou, Ding-Wei

The emulsion liquid membrane (ELM) technique has been successfully applied on the removal of arsenic (As) from metallurgical wastewater and the removal of strontium (Sr) from radioactive wastewater. This study consisted of experimental work and mathematical modeling. Extraction of arsenic by an emulsion liquid membrane was firstly investigated. The liquid membrane used was composed of 2-ethylhexyl alcohol (2EHA) as the extractant, ECA4360J as the surfactant, and Exxsol D-80 solvent (or heptane) as the diluent. The sulfuric acid and sodium hydroxide solutions were used as the external and internal phases, respectively. The arsenic removal efficiency reached 92% within 15 minutes in one stage. Extraction and stripping chemistries were postulated and investigated. It was observed that extraction efficiency and rate increase with the increase of acidic strength and alkali strength in the external and internal phases, respectively. It was also observed that the removal selectivity of arsenic over copper is extremely high. Strontium-90 is one of the major radioactive metals appearing in nuclear wastewater. The emulsion liquid membrane process was investigated as a separation method by using the non-radioactive ^{87}Sr as its substitute. In our study, the membrane phase was composed of di-(2-ethylhexyl) phosphoric acid (D2EHPA) as the extractant, ECA4360J as the surfactant and Exxsol D-80 as the diluent. A sulfuric acid solution was used in the internal phase as the stripping agent. The pH range in the external phase was determined by the extraction isotherm. Under the most favorable operating condition, the strontium removal efficiency can reach 98% in two minutes. Mass transfer of the emulsion liquid membrane (ELM) system was modeled mathematically. Our model took into account the following: mass transfer of solute across the film between the external phase and the membrane phase, chemical equilibrium of the extraction reaction at the external phase-membrane interface, simultaneous diffusion of the solute-carrier complex inside the globule membrane phase and stripping of the complex at the membrane-internal phase interface, chemical equilibrium of the stripping reaction at the membrane-internal phase interface and leakage of the solute from the internal phase to the external phase. Resulting simultaneous partial differential equations were solved analytically by the Laplace transform method. Four dimensionless groups were found with special physical meanings to characterize the emulsion liquid membrane systems. It not only predicted the concentration of solute in the external phase versus time, but also gave the concentration profile inside the membrane globule and the interfacial concentration at the external-membrane phase interface at different time. The model predicted very well the experimental data obtained from the removal of arsenic and strontium by the emulsion liquid membranes.

Liquid crystal nanoparticles for delivery of photosensitizers for photodynamic therapy

NASA Astrophysics Data System (ADS)

Nag, Okhil K.; Naciri, Jawad; Delehanty, James B.

2018-02-01

The main principle of photodynamic therapy (PDT) is to kill malignant cells by generation of reactive oxygen species (ROS). PDT appeared highly effective when ROS can be produced in subcellular location such as plasma membrane. The plasma membrane maintains the structural integrity of the cell and regulates multiple important cellular processes, such as endocytosis, trafficking, and apoptotic pathways, could be one of the best points to kill the cancer cells. Previously, we have developed a plasma membrane-targeted liquid crystal nanoparticle (LCNP) formulation that can be loaded with dyes or drugs. Here we highlight the utility of this LCNP for membrane targeted delivery and imaging for a photosensitizer (PS) for PDT applications.

Selective separation of furfural and hydroxymethylfurfural from an aqueous solution using a supported hydrophobic deep eutectic solvent liquid membrane.

PubMed

Dietz, Carin H J T; Kroon, Maaike C; Di Stefano, Michela; van Sint Annaland, Martin; Gallucci, Fausto

2017-12-14

For the first time, 12 different supported deep eutectic solvent (DES) liquid membranes were prepared and characterized. These membranes consist of a polymeric support impregnated with a hydrophobic DES. First, the different membranes were characterized and their stability in water and air was determined. Subsequently, the supported DES liquid membranes were applied for the recovery of furfural (FF) and hydroxymethylfurfural (HMF) from aqueous solutions. The effects of substrate properties (e.g. pore size), DES properties (e.g. viscosity) and concentrations of FF and HMF in the feed phase on the observed diffusivities and permeabilities were assessed. It was found that the addition of DES enhances the transport of FF and HMF through the polymeric membrane support. In particular, the use of the DES consisting of thymol + lidocaine (in the molar ratio 2 : 1) impregnated in a polyethylene support resulted in enhanced transport for both FF and HMF, and is most interesting for (in situ) isolation of FF and HMF from aqueous solutions, e.g. in biorefinery processes.

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

A new project was initiated this quarter to develop gas/liquid membranes for natural gas upgrading. Efforts have concentrated on legal agreements, including alternative field sites. 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 absorbingmore » 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.« less

NMR Studies of Mass Transport in New Conducting Media for Fuel Cells

DTIC Science & Technology

2009-01-01

PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the short range by spin-lattice...structural environments of muticomponent PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the...correlation between water diffusivity and proton conductivity in the nanocomposites Transport properties of several ionic liquids (IL’s) and membranes

Shock wave-droplet interaction

NASA Astrophysics Data System (ADS)

Habibi Khoshmehr, Hamed; Krechetnikov, Rouslan

2016-11-01

Disintegration of a liquid droplet under the action of a shock wave is experimentally investigated. The shock wave-pulse is electromagnetically generated by discharging a high voltage capacitor into a flat spiral coil, above which an isolated circular metal membrane is placed in a close proximity. The Lorentz force arising due to the eddy current induced in the membrane abruptly accelerates it away from the spiral coil thus generating a shock wave. The liquid droplet placed at the center of the membrane, where the maximum deflection occurs, is disintegrated in the process of interaction with the shock wave. The effects of droplet viscosity and surface tension on the droplet destruction are studied with high-speed photography. Water-glycerol solution at different concentrations is used for investigating the effect of viscosity and various concentrations of water-sugar and water-ethanol solution are used for studying the effect of surface tension. Here we report on how the metamorphoses, which a liquid drop undergoes in the process of interaction with a shock wave, are affected by varied viscosity and surface tension.

Treatment of evaporator condensates by pervaporation

DOEpatents

Blume, Ingo; Baker, Richard W.

1990-01-01

A pervaporation process for separating organic contaminants from evaporator condensate streams is disclosed. The process employs a permselective membrane that is selectively permeable to an organic component of the condensate. The process involves contacting the feed side of the membrane with a liquid condensate stream, and withdrawing from the permeate side a vapor enriched in the organic component. The driving force for the process is the in vapor pressure across the membrane. This difference may be provided for instance by maintaining a vacuum on the permeate side, or by condensing the permeate. The process offers a simple, economic alternative to other separation techniques.

Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic Membrane Contactor Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Howard; Zhou, S James; Ding, Yong

2012-03-31

This report summarizes progress made during Phase I and Phase II of the project: "Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic Membrane Contactor Process," under contract DE-FE-0000646. The objective of this project is to develop a practical and cost effective technology for CO{sub 2} separation and capture for pre-combustion coal-based gasification plants using a membrane contactor/solvent absorption process. The goals of this technology development project are to separate and capture at least 90% of the CO{sub 2} from Integrated Gasification Combined Cycle (IGCC) power plants with less than 10% increase in the cost of energy services. Unlike conventional gas separationmore » membranes, the membrane contactor is a novel gas separation process based on the gas/liquid membrane concept. The membrane contactor is an advanced mass transfer device that operates with liquid on one side of the membrane and gas on the other. The membrane contactor can operate with pressures that are almost the same on both sides of the membrane, whereas the gas separation membranes use the differential pressure across the membrane as driving force for separation. The driving force for separation for the membrane contactor process is the chemical potential difference of CO{sub 2} in the gas phase and in the absorption liquid. This process is thus easily tailored to suit the needs for pre-combustion separation and capture of CO{sub 2}. Gas Technology Institute (GTI) and PoroGen Corporation (PGC) have developed a novel hollow fiber membrane technology that is based on chemically and thermally resistant commercial engineered polymer poly(ether ether ketone) or PEEK. The PEEK membrane material used in the membrane contactor during this technology development program is a high temperature engineered plastic that is virtually non-destructible under the operating conditions encountered in typical gas absorption applications. It can withstand contact with most of the common treating solvents. GTI and PGC have developed a nanoporous and superhydrophobic PEEK-based hollow fiber membrane contactor tailored for the membrane contactor/solvent absorption application for syngas cleanup. The membrane contactor modules were scaled up to 8-inch diameter commercial size modules. We have performing extensive laboratory and bench testing using pure gases, simulated water-gas-shifted (WGS) syngas stream, and a slipstream from a gasification derived syngas from GTI's Flex-Fuel Test Facility (FFTF) gasification plant under commercially relevant conditions. The team have also carried out an engineering and economic analysis of the membrane contactor process to evaluate the economics of this technology and its commercial potential. Our test results have shown that 90% CO{sub 2} capture can be achieved with several physical solvents such as water and chilled methanol. The rate of CO{sub 2} removal by the membrane contactor is in the range of 1.5 to 2.0 kg/m{sup 2}/hr depending on the operating pressures and temperatures and depending on the solvents used. The final economic analysis has shown that the membrane contactor process will cause the cost of electricity to increase by 21% from the base plant without CO{sub 2} capture. The goal of 10% increase in levelized cost of electricity (LCOE) from base DOE Case 1(base plant without capture) is not achieved by using the membrane contactor. However, the 21% increase in LCOE is a substantial improvement as compared with the 31.6% increase in LCOE as in DOE Case 2(state of art capture technology using 2-stages of Selexol{TM}).« less

Optimization of Wastewater of Batik Buaran Pekalongan by Using Photocatalytic Membrane Bioreactor

NASA Astrophysics Data System (ADS)

Arifan, Fahmi; Nugraheni, FS; Lianandaya, Niken Elsa

2018-02-01

The purpose of this study is to determine the final COD concentration reduction by changing COD and MLSS concentration on the performance of submerged membrane bioreactor (MBRs) as a waste treatment of Batik in Buaran Pekalongan. The method is covers the process of seeding, the acclimatization process and the main process. Description of the process that we take an active mud from IPLT Buaran Pekalongan, then we analyze the sludge MLSS, MLVSS, COD, BOD, and TSS. After that we enter the active sludge in the bath nursery that has been given aerator (a tool for aeration) and made provision in the form of NPK nutrients and glucose at a ratio of 1:10. Activated sludge from the acclimatization process is inserted into the MBRs (membrane bioreactor submerged) that is equipped with an aerator. Then prepare influent(waste to be lowered concentration of COD). How, liquid waste of Batik Pekalongan Buaran COD diluted concentration of 10,000 mg / l and 15,000 mg / l, and then inserted in influent tub. After that liquid waste of Batik Buaran Pekalongan influent flowed into Photocatalytic Membrane Bioreactor, of MPB effluent flowed into the tub (result).

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.

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

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 inmore » 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. KPS 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 legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues.« less

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

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 inmore » 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 legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues.« less

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment continues. 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 muchmore » 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.« less

A supported liquid membrane system for the selective recovery of rare earth elements from neodymium-based permanent magnets

DOE PAGES

Kim, Daejin; Powell, Lawrence; Delmau, Lætitia H.; ...

2016-04-04

We present that the rare earth elements (REEs) play a vital role in the development of green energy and high-tech industries. In order to meet the fast-growing demand and to ensure sufficient supply of the REEs, it is essential to develop an efficient REE recovery process from post-consumer REE-containing products. In this research effort, we have developed a supported liquid membrane system utilizing polymeric hollow fiber modules to extract REEs from neodymium-based magnets with neutral extractants such as tetraoctyl digylcol amide (TODGA). The effect of process variables such as REE concentration, molar concentration of acid, and membrane area on REEmore » recovery was investigated. We have demonstrated the selective extraction and recovery of REEs such as Nd, Pr, and Dy without co-extraction of non-REEs from permanent NdFeB magnets through the supported liquid membrane system. The extracted REEs were then recovered by precipitation followed by the annealing step to obtain crystalline REE powders in nearly pure form. Finally, the recovered REE oxides were characterized by X-ray diffraction, scanning electron microscope coupled with energy-dispersive X-ray spectroscopy, and inductively coupled plasma–optical emission spectroscopy.« less

Membranes for Food and Bioproduct Processing

NASA Astrophysics Data System (ADS)

Avram, Alexandru M.

Modified membranes for process intensification in biomass hydrolysis: Production of biofuels and chemicals from lignocellulosic biomass is one of the leading candidates for replacement of petroleum based fuels and chemicals. However, conversion of lignocellulosic biomass into fuels and chemicals is not cost effective compared to the production of fuels and chemicals from crude oil reserves. Some novel and economically feasible approaches involve the use of ionic liquids as solvents or co-solvents, since these show improved solvation capability of cellulose over simple aqueous systems. Membranes offer unique opportunities for process intensification which involves fractionation of the resulting biomass hydrolysate leading to a more efficient and cheaper operation. This research attempts to develop membranes that would usher the economics of the biochemical conversion of lignocellulosic biomass into fuels and chemicals by recycling the expensive ionic liquid. The overall aim of this work is the development of novel membranes with unique surface properties that enable the selective separation of non-reacted cellulose and hydrolysis sugars from ionic liquids. Nanofiltration separation for application in food product engineering: With the advent of the modern, well-informed consumer who has high expectations from the nutritional value of consumed food products, novel approaches are being developed to produce nutrient-enhanced foods and drinks. As a response to the consumer needs, different techniques to recover, concentrate and retain as much as possible of bioactive compounds are being investigated. Membrane technology has the advantage of selective fractionation of food products (e.g. salt removal, removal of bitter-tasting compounds or removal of sugar for sweet taste adjustment), volume reduction, and product recovery at mild conditions. In this work, we use nanofiltration in dead-end and crossflow mode to concentrate polyphenols from blueberry pomace. Blueberry pomace is an overlooked waste product form the juice pressing of blueberries that contains high amounts of health-beneficial antioxidants. We aim at developing a simple, yet efficient membrane process that reduces the amount of water and thus concentrates the amount of polyphenols in the retentate.

Effect of polymer concentration on the structure and performance of PEI hollow fiber membrane contactor for CO2 stripping.

PubMed

Naim, R; Ismail, A F

2013-04-15

A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13-16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10(-2)mol/m(2)s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor. Copyright © 2013 Elsevier B.V. All rights reserved.

Asymmetric block copolymer membranes with ultrahigh porosity and hierarchical pore structure by plain solvent evaporation.

PubMed

Yu, H; Qiu, X; Behzad, A R; Musteata, V; Smilgies, D-M; Nunes, S P; Peinemann, K-V

2016-10-04

Membranes with a hierarchical porous structure could be manufactured from a block copolymer blend by pure solvent evaporation. Uniform pores in a 30 nm thin skin layer supported by a macroporous structure were formed. This new process is attractive for membrane production because of its simplicity and the lack of liquid waste.

Physics of smectic membranes

NASA Astrophysics Data System (ADS)

Pieranski, P.; Beliard, L.; Tournellec, J.-Ph.; Leoncini, X.; Furtlehner, C.; Dumoulin, H.; Riou, E.; Jouvin, B.; Fénerol, J.-P.; Palaric, Ph.; Heuving, J.; Cartier, B.; Kraus, I.

1993-03-01

Due to their layered structure, smectic liquid crystals can form membranes, similar to soap bubbles, that can be spanned on frames. Such smectic membranes have been used extensively as samples in many structural X-ray studies of smectic liquid crystals. In this context they have been considered as very convenient and highly perfect samples but little attention has been paid to the reasons for their existence and to the process of their formation. Our aim here is to address a first list of questions, which are the most urgent to answer. We will also describe experiments and models that have been conceived especially in order to understand the physics of these fascinating systems.

Separation process using pervaporation and dephlegmation

DOEpatents

Vane, Leland M.; Mairal, Anurag P.; Ng, Alvin; Alvarez, Franklin R.; Baker, Richard W.

2004-06-29

A process for treating liquids containing organic compounds and water. The process includes a pervaporation step in conjunction with a dephlegmation step to treat at least a portion of the permeate vapor from the pervaporation step. The process yields a membrane residue stream, a stream enriched in the more volatile component (usually the organic) as the overhead stream from the dephlegmator and a condensate stream enriched in the less volatile component (usually the water) as a bottoms stream from the dephlegmator. Any of these may be the principal product of the process. The membrane separation step may also be performed in the vapor phase, or by membrane distillation.

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

PubMed

Tomé, Liliana C; Marrucho, Isabel M

2016-05-21

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

Ionomer-Membrane Water Processing Methods

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(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.

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.

Ionomer-Membrane Water Processing Apparatus

NASA Technical Reports Server (NTRS)

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

2017-01-01

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.RTM., 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.

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

Efforts this quarter have concentrated on legal agreements, including alternative field sites. Preliminary design of the bench-scale equipment has been initiated. 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 membranesmore » 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.« less

A low cost adaptive silicone membrane lens

NASA Astrophysics Data System (ADS)

Schneider, F.; Müller, C.; Wallrabe, U.

2008-04-01

This article introduces adaptive liquid lenses with thick silicone membranes of 5 mm diameter. These membranes are produced by means of casting in a batch process. The lenses feature an integrated piezo-bending actuator, which is also embedded in silicone. The lenses presented comprise areas of application which are not covered by the electrowetting lenses (diameter <3 mm) already established on the market.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Clare L; Marquardt, Drew; Dies, Hannah

Rafts, or functional domains, are transient nano- or mesoscopic structures in the exoplasmic leaflet of the plasma membrane, and are thought to be essential for many cellular processes. Using neutron diffraction and computer modelling, we present evidence for the existence of highly ordered lipid domains in the cholesterol-rich (32.5 mol%) liquid-ordered (lo) phase of dipalmitoylphosphatidylcholine membranes. The liquid ordered phase in one-component lipid membranes has previously been thought to be a homogeneous phase. The presence of highly ordered lipid domains embedded in a disordered lipid matrix implies non-uniform distribution of cholesterol between the two phases. The experimental results are inmore » excellent agreement with recent computer simulations of DPPC/cholesterol complexes [Meinhardt, Vink and Schmid (2013). Proc Natl Acad Sci USA 110(12): 4476 4481], which reported the existence of nanometer size lo domains in a liquid disordered lipid environment.« less

Review of hydrophilic PP membrane for organic waste removal

NASA Astrophysics Data System (ADS)

Ariono, Danu; Wardani, Anita Kusuma

2017-05-01

The acceleration of industrialization in developing countries has given an impact of environmental pollution rapidly, such as contamination of groundwater with organic waste. To solve this problem, some membrane techniques have been performed to remove organic waste from water, such as membrane contactors, membrane bioreactors, and supported liquid membranes. Polypropylene (PP) membrane is one of the promising candidates for these membrane processes due to its chemical stability, low cost, good mechanical resistance, and being easily available. However, different processes require membranes with different surface properties. Hydrophobic PP membranes with excellent chemical stability can be directly used in membrane contactors, in which the organic phase wets the porous membrane and slightly excessive pressure applied to the other phase. On the other hand, hydrophilization of PP membrane is necessary for some other processes, such as for fouling reduction on membrane bioreactors due to organic matters deposition. The aim of this paper is to give a brief overview of removal of organic waste by PP membrane. Moreover, the effects of PP surface hydrophilization on antifouling properties are also discussed.

In situ liquid water visualization in polymer electrolyte membrane fuel cells with high resolution synchrotron x-ray radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chevalier, S.; Banerjee, R.; Lee, J.

In this work, we investigated the dominating properties of the porous materials that impact water dynamics in a polymer electrolyte membrane fuel cell (PEMFC). Visualizations of liquid water in an operating PEMFC were performed at the Canadian Light Source. A miniature fuel cell was specifically designed for X-ray imaging investigations, and an in-house image processing algorithm based on the Beer-Lambert law was developed to extract quantities of liquid water thicknesses (cm) from raw X-ray radiographs. The X-ray attenuation coefficient of water at 24 keV was measured with a calibration device to ensure accurate measurements of the liquid water thicknesses. Frommore » this experiment, the through plane distribution of the liquid water in the fuel cell was obtained.« less

INTEGRATION OF FILTRATION AND ADVANCED OXIDATION: DEVELOPMENT OF A MEMBRANE LIQUID-PHASE PLASMA REACTOR

EPA Science Inventory

A tiered approach will be undertaken to achieve the overall project goal of demonstrating the integrated membrane/plasma process as an innovative, affordable, sustainable and effective treatment technology for small treatment systems. The team will first use a regimented ap...

Gas Separation Using Organic-Vapor-Resistent Membranes In Conjunctin With Organic-Vapor-Selective Membranes

DOEpatents

Baker, Richard W.; Pinnau, Ingo; He, Zhenjie; Da Costa, Andre R.; Daniels, Ramin; Amo, Karl D.; Wijmans, Johannes G.

2003-06-03

A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

Application of a macrocyclic compound, bambus[6]uril, in tailor-made liquid membranes for highly selective electromembrane extractions of inorganic anions.

PubMed

Šlampová, Andrea; Šindelář, Vladimír; Kubáň, Pavel

2017-01-15

A tailor-made liquid membrane consisting of a resistive organic solvent (nitrobenzene, NB) and a highly selective non-ionic macrocyclic compound (bambus[6]uril, BU6) was employed for electromembrane extraction (EME) of inorganic anions. BU6 facilitates strong host-guest interactions of its internal cavity with selected inorganic anions only and its presence in the liquid membrane ensured excellent selectivity of the EME process. EME transfers were directly related to association constants between BU6 and inorganic anions and nearly absolute selectivity was achieved for EMEs of iodide, bromide and perchlorate. Major inorganic anions (chloride, nitrate, sulphate and carbonate), which exhibit low interactions with BU6 cavity, were efficiently eliminated from the EME transfer. No interferences were observed for EMEs of target analytes from samples containing up to 100.000-fold higher concentrations of the major anions. Addition of species-specific macrocyclic modifiers to free and supported liquid membranes might thus open new directions in fine-tuning of EME selectivity. At optimized EME conditions (polypropylene hollow fiber impregnated with NB + 3% (w/w) BU6, extraction voltage 25 V, extraction time 15 min, deionized water as acceptor solution) perchlorate was selectively extracted from tap water at concentrations below the guideline value recommended by United States Environmental Protection Agency. Excellent selectivity of the tailor-made liquid membrane was further demonstrated by EME of bromide from sea water. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid oxide membrane (SOM) process for ytterbium and silicon production from their oxides

NASA Astrophysics Data System (ADS)

Jiang, Yihong

The Solid oxide membrane (SOM) electrolysis is an innovative green technology that produces technologically important metals directly from their respective oxides. A yttria-stabilized zirconia (YSZ) tube, closed at one end is employed to separate the molten salt containing dissolved metal oxides from the anode inside the YSZ tube. When the applied electric potential between the cathode in the molten salt and the anode exceeds the dissociation potential of the desired metal oxides, oxygen ions in the molten salt migrate through the YSZ membrane and are oxidized at the anode while the dissolved metal cations in the flux are reduced to the desired metal at the cathode. Compared with existing metal production processes, the SOM process has many advantages such as one unit operation, less energy consumption, lower capital costs and zero carbon emission. Successful implementation of the SOM electrolysis process would provide a way to mitigate the negative environmental impact of the metal industry. Successful demonstration of producing ytterbium (Yb) and silicon (Si) directly from their respective oxides utilizing the SOM electrolysis process is presented in this dissertation. During the SOM electrolysis process, Yb2O3 was reduced to Yb metal on an inert cathode. The melting point of the supporting electrolyte (LiF-YbF3-Yb2O3) was determined by differential thermal analysis (DTA). Static stability testing confirmed that the YSZ tube was stable with the flux at operating temperature. Yb metal deposit on the cathode was confirmed by scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). During the SOM electrolysis process for silicon production, a fluoride based flux based on BaF2, MgF2, and YF3 was engineered to serve as the liquid electrolyte for dissolving silicon dioxide. YSZ tube was used to separate the molten salt from an anode current collector in the liquid silver. Liquid tin was chosen as cathode to dissolve the reduced silicon during SOM electrolysis. After electrolysis, upon cooling, silicon crystals precipitated out from the Si-Sn liquid alloy. The presence of high-purity silicon crystals in the liquid tin cathode was confirmed by SEM/EDS. The fluoride based flux was also optimized to improve YSZ membrane stability for long-term use.

ATR-FTIR membrane-based sensor for the simultaneous determination of surfactant and oil total indices in industrial degreasing baths.

PubMed

Lucena, Rafael; Cárdenas, Soledad; Gallego, Mercedes; Valcárcel, Miguel

2006-03-01

Monitoring the exhaustion of alkaline degreasing baths is one of the main aspects in metal mechanizing industrial process control. The global level of surfactant, and mainly grease, can be used as ageing indicators. In this paper, an attenuated total reflection-Fourier transform infrared (ATR-FTIR) membrane-based sensor is presented for the determination of these parameters. The system is based on a micro-liquid-liquid extraction of the analytes through a polymeric membrane from the aqueous to the organic solvent layer which is in close contact with the internal reflection element and continuously monitored. Samples are automatically processed using a simple, robust sequential injection analysis (SIA) configuration, on-line coupled to the instrument. The global signal obtained for both families of compounds are processed via a multivariate calibration technique (partial least squares, PLS). Excellent correlation was obtained for the values given by the proposed method compared to those of the gravimetric reference one with very low error values for both calibration and validation.

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.

The use of holographic interferometry and electron speckle pattern interferometry for diffusion measurement in biochemical and pharmaceutical engineering applications

NASA Astrophysics Data System (ADS)

Axelsson, Anders; Marucci, Mariagrazia

2008-12-01

In this review holographic interferometry and electron speckle pattern interferometry are discussed as efficient techniques for diffusion measurements in biochemical and pharmaceutical applications. Transport phenomena can be studied, quantitatively and qualitatively, in gels, liquids and membranes. Detailed information on these phenomena is required to design effective chromatography bioseparation processes using gel beads or ultrafiltration membranes, and in the design of controlled-release pharmaceuticals using membrane-coated pellets or tablets. The influence of gel concentration, ion strength in the liquid and the size of diffusing protein molecules can easily be studied with good accuracy. When studying membranes, the resistance can be quantified, and it is also possible to discriminate between permeable and semi-permeable membranes. In this review the influence of temperature, natural convection and light deflection on the accuracy of the diffusion measurements is also discussed.

Anhydrous Proton-Conducting Membranes for Fuel Cells

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram; Yen, Shiao-Pin S.

2005-01-01

Polymeric electrolyte membranes that do not depend on water for conduction of protons are undergoing development for use in fuel cells. Prior polymeric electrolyte fuel-cell membranes (e.g., those that contain perfluorosulfonic acid) depend on water and must be limited to operation below a temperature of 125 C because they retain water poorly at higher temperatures. In contrast, the present developmental anhydrous membranes are expected to function well at temperatures up to 200 C. The developmental membranes exploit a hopping-and-reorganization proton- conduction process that can occur in the solid state in organic amine salts and is similar to a proton-conduction process in a liquid. This process was studied during the 1970s, but until now, there has been no report of exploiting organic amine salts for proton conduction in fuel cells.

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

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 inmore » 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. KPS 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. Potting and module materials testing were initiated. Preliminary design of the bench-scale equipment continues.« less

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

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 inmore » 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 and module materials testing continued. Preliminary design of the bench-scale equipment continues.« less

Opportunities and Challenges in Application of Forward Osmosis in Food Processing.

PubMed

Rastogi, Navin K

2016-01-01

Food processing and preservation technologies must maintain the fresh-like characteristics of food while providing an acceptable and convenient shelf life as well as assuring safety and nutritional value. Besides, the consumers' demand for the highest quality convenience foods in terms of natural flavor and taste, free from additives and preservatives necessitated the development of a number of membrane-based non-thermal approaches to the concentration of liquid foods, of which forward osmosis has proven to be the most valuable one. A series of recent publications in scientific journals have demonstrated novel and diverse uses of this technology for food processing, desalination, pharmaceuticals as well as for power generation. Its novel features, which include the concentration of liquid foods at ambient temperature and pressure without significant fouling of membrane, made the technology commercially attractive. This review aims to identify the opportunities and challenges associated with this technology. At the same time, it presents a comprehensive account of recent advances in forward osmosis technology as related to the major issues of concern in its rapidly growing applications in food processing such as concentration of fruit and vegetable juices (grape, pineapple, red raspberry, orange, and tomato juice and red radish juice) and natural food colorants (anthocyanin and betalains extracts). Several vibrant and vital issues such as recent developments in the forward osmosis membrane and concentration polarization aspects have been also addressed. The asymmetric membrane used for forward osmosis poses newer challenges to account both external and internal concentration polarization leading to significant reduction in flux. The recent advances and developments in forward osmosis membrane processes, mechanism of water transport, characteristics of draw solution and membranes as well as applications of forward osmosis in food processing have been discussed.

Carbon membranes for efficient water-ethanol separation.

PubMed

Gravelle, Simon; Yoshida, Hiroaki; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

2016-09-28

We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely, carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale "graphene-oxide" like membranes then opens an avenue for a versatile and efficient ethanol dehydration using this separation process, with possible application for bio-ethanol fabrication.

Carbon membranes for efficient water-ethanol separation

NASA Astrophysics Data System (ADS)

Gravelle, Simon; Yoshida, Hiroaki; Joly, Laurent; Ybert, Christophe; Bocquet, Lydéric

2016-09-01

We demonstrate, on the basis of molecular dynamics simulations, the possibility of an efficient water-ethanol separation using nanoporous carbon membranes, namely, carbon nanotube membranes, nanoporous graphene sheets, and multilayer graphene membranes. While these carbon membranes are in general permeable to both pure liquids, they exhibit a counter-intuitive "self-semi-permeability" to water in the presence of water-ethanol mixtures. This originates in a preferred ethanol adsorption in nanoconfinement that prevents water molecules from entering the carbon nanopores. An osmotic pressure is accordingly expressed across the carbon membranes for the water-ethanol mixture, which agrees with the classic van't Hoff type expression. This suggests a robust and versatile membrane-based separation, built on a pressure-driven reverse-osmosis process across these carbon-based membranes. In particular, the recent development of large-scale "graphene-oxide" like membranes then opens an avenue for a versatile and efficient ethanol dehydration using this separation process, with possible application for bio-ethanol fabrication.

Suspended sub-50 nm vanadium dioxide membrane transistors: fabrication and ionic liquid gating studies

NASA Astrophysics Data System (ADS)

Sim, Jai S.; Zhou, You; Ramanathan, Shriram

2012-10-01

We demonstrate a robust lithographic patterning method to fabricate self-supported sub-50 nm VO2 membranes that undergo a phase transition. Utilizing such self-supported membranes, we directly observed a shift in the metal-insulator transition temperature arising from stress relaxation and consistent opening of the hysteresis. Electric double layer transistors were then fabricated with the membranes and compared to thin film devices. The ionic liquid allowed reversible modulation of channel resistance and distinguishing bulk processes from the surface effects. From the shift in the metal-insulator transition temperature, the carrier density doped through electrolyte gating is estimated to be 1 × 1020 cm-3. Hydrogen annealing studies showed little difference in resistivity between the film and the membrane indicating rapid diffusion of hydrogen in the vanadium oxide rutile lattice consistent with previous observations. The ability to fabricate electrically-wired, suspended VO2 ultra-thin membranes creates new opportunities to study mesoscopic size effects on phase transitions and may also be of interest in sensor devices.

CFD simulation of copper(II) extraction with TFA in non-dispersive hollow fiber membrane contactors.

PubMed

Muhammad, Amir; Younas, Mohammad; Rezakazemi, Mashallah

2018-04-01

This study presents computational fluid dynamics (CFD) simulation of dispersion-free liquid-liquid extraction of copper(II) with trifluoroacetylacetone (TFA) in hollow fiber membrane contactor (HFMC). Mass and momentum balance Navier-Stokes equations were coupled to address the transport of copper(II) solute across membrane contactor. Model equations were simulated using COMSOL Multiphysics™. The simulation was run to study the detailed concentration distribution of copper(II) and to investigate the effects of various parameters like membrane characteristics, partition coefficient, and flow configuration on extraction efficiency. Once-through extraction was found to be increased from 10 to 100% when partition coefficient was raised from 1 to 10. Similarly, the extraction efficiency was almost doubled when porosity to tortuosity ratio of membrane was increased from 0.05 to 0.81. Furthermore, the study revealed that CFD can be used as an effective optimization tool for the development of economical membrane-based dispersion-free extraction processes.

Polymeric Nanocomposite Membranes for Next Generation Pervaporation Process: Strategies, Challenges and Future Prospects.

PubMed

Roy, Sagar; Singha, Nayan Ranjan

2017-09-08

Pervaporation (PV) has been considered as one of the most active and promising areas in membrane technologies in separating close boiling or azeotropic liquid mixtures, heat sensitive biomaterials, water or organics from its mixtures that are indispensable constituents for various important chemical and bio-separations. In the PV process, the membrane plays the most pivotal role and is of paramount importance in governing the overall efficiency. This article evaluates and collaborates the current research towards the development of next generation nanomaterials (NMs) and embedded polymeric membranes with regard to its synthesis, fabrication and application strategies, challenges and future prospects.

Polymeric Nanocomposite Membranes for Next Generation Pervaporation Process: Strategies, Challenges and Future Prospects

PubMed Central

Singha, Nayan Ranjan

2017-01-01

Pervaporation (PV) has been considered as one of the most active and promising areas in membrane technologies in separating close boiling or azeotropic liquid mixtures, heat sensitive biomaterials, water or organics from its mixtures that are indispensable constituents for various important chemical and bio-separations. In the PV process, the membrane plays the most pivotal role and is of paramount importance in governing the overall efficiency. This article evaluates and collaborates the current research towards the development of next generation nanomaterials (NMs) and embedded polymeric membranes with regard to its synthesis, fabrication and application strategies, challenges and future prospects. PMID:28885591

The casting of semi-permeable membranes in a microgravity environment

NASA Technical Reports Server (NTRS)

Vera, I.

1986-01-01

The experiment is to study polymeric membranes. Presently, semipermeable membranes are being manufactured from several different kinds of polymers all over the world and specific applications have been identified in fluid separation processes such as reverse osmosis, ultrafiltration and electrodialysis. Although, the ultrastructure of asymmetric and composite membranes have been under intensive study, still there are many questions about the factors affecting this structure and their degree of correlation. Nevertheless, there is indication that the entire morphological structure of polymeric membranes could be affected by the difference in specific gravity between the cast solution and the coagulation liquid normally used in the membranes preparation process. The casting of semipermeable membranes in space might help to identify the effect of gravity upon the structure of these membranes. It is important to recognize that the casting process involves changes of state and that in a microgravity environment, there will be a reduction on buoyancy-driven natural convection and density gradients.

Graphene Microcapsule Arrays for Combinatorial Electron Microscopy and Spectroscopy in Liquids

DOE PAGES

Yulaev, Alexander; Guo, Hongxuan; Strelcov, Evgheni; ...

2017-04-27

Atomic-scale thickness, molecular impermeability, low atomic number, and mechanical strength make graphene an ideal electron-transparent membrane for material characterization in liquids and gases with scanning electron microscopy and spectroscopy. Here in this paper, we present a novel sample platform made of an array of thousands of identical isolated graphene-capped microchannels with high aspect ratio. A combination of a global wide field of view with high resolution local imaging of the array allows for high throughput in situ studies as well as for combinatorial screening of solutions, liquid interfaces, and immersed samples. We demonstrate the capabilities of this platform by studyingmore » a pure water sample in comparison with alkali halide solutions, a model electrochemical plating process, and beam-induced crystal growth in liquid electrolyte. Spectroscopic characterization of liquid interfaces and immersed objects with Auger and X-ray fluorescence analysis through the graphene membrane are also demonstrated.« less

Preliminary characterization of carbon dioxide transfer in a hollow fiber membrane module as a possible solution for gas-liquid transfer in microgravity conditions

NASA Astrophysics Data System (ADS)

Farges, Bérangère; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-François

2012-01-01

In microgravity, one of the major challenge encountered in biological life support systems (BLSS) is the gas-liquid transfer with, for instance, the necessity to provide CO2 (carbon source, pH control) and to recover the evolved O2 in photobioreactors used as atmosphere bioregenerative systems.This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module used as a possible efficient solution to the microgravity gas-liquid transfer. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient kLCO obtained in case of absorption experiments at pH 8 using the hollow fiber membrane module. The consistency of the proposed method, based on a gas and liquid phase balances verifying carbon conservation enables a very accurate determination of the kLCO value as a main limiting step of the whole process. Nevertheless, further experiments are still needed to demonstrate that the proposed method could serve in the future as reference method for mass transfer coefficient determination if using membrane modules for BLSS in reduced or microgravity conditions.

Propagation of a viscous thin film over an elastic membran

NASA Astrophysics Data System (ADS)

Zheng, Zhong; Griffiths, Ian; Stone, Howard

2016-11-01

We study the buoyancy-driven spreading of a thin viscous film over a thin elastic membrane. Neglecting the effects of membrane bending and the membrane weight, we study the case of constant fluid injection and obtain a system of coupled partial differential equations to describe the shape of the air-liquid interface, and the deformation and the radial tension of the stretched membrane. We obtain self-similar solutions to describe the dynamics. In particular, in the early time period, the dynamics is dominated by buoyancy-driven spreading of the liquid film, and membrane stretching is a response to the buoyancy-controlled distribution of liquid weight; the location of the liquid front obeys the power-law form rf (t) t 1 / 2 . However, in the late time period, the system is quasi-steady, the air-liquid interface is flat, and membrane stretching, due to the liquid weight, causes the spreading of the liquid front; the location of the front obeys a different power-law form rf (t) t 1 / 4 before the edge effects of the membrane become significant. In addition, we report laboratory experiments for constant fluid injection using different viscous liquids and thin elastic membranes. Very good agreement is obtained between the theory and experiments.

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

NASA Technical Reports Server (NTRS)

Wiencek, John M.; Hu, Shih-Yao

2000-01-01

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

Treatment of radioactive liquid effluents by reverse osmosis membranes: From lab-scale to pilot-scale.

PubMed

Combernoux, Nicolas; Schrive, Luc; Labed, Véronique; Wyart, Yvan; Carretier, Emilie; Moulin, Philippe

2017-10-15

The recent use of the reverse osmosis (RO) process at the damaged Fukushima-Daiichi nuclear power plant generated a growing interest in the application of this process for decontamination purposes. This study focused on the development of a robust RO process for decontamination of two kinds of liquid effluents: a contaminated groundwater after a nuclear disaster and a contaminated seawater during a nuclear accident. The SW30 HR membrane was selected among other in this study due to higher retentions (96% for Cs and 98% for Sr) in a true groundwater. Significant fouling and scaling phenomenon, attributed to calcium and strontium precipitation, were evidenced in this work: this underscored the importance of the lab scale experiment in the process. Validation of the separation performances on trace radionuclides concentration was performed with similar retention around 96% between surrogates Cs (inactive) and 137 Cs (radioactive). The scale up to a 2.6 m 2 spiral wound membrane led to equivalent retentions (around 96% for Cs and 99% for Sr) but lower flux values: this underlined that the hydrodynamic parameters (flowrate/cross-flow velocity) should be optimized. This methodology was also applied on the reconstituted seawater effluent: retentions were slightly lower than for the groundwater and the same hydrodynamic effects were observed on the pilot scale. Then, ageing of the membrane through irradiation experiments were performed. Results showed that the membrane active layer composition influenced the membrane resistance towards γ irradiation: the SW30 HR membrane performances (retention and permeability) were better than the Osmonics SE at 1 MGy. Finally, to supplement the scale up approach, the irradiation of a spiral wound membrane revealed a limited effect on the permeability and retention. This indicated that irradiation conditions need to be controlled for a further development of the process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recovery of ammonia nitrogen in livestock and industrial wastes using gas permeable membranes

USDA-ARS?s Scientific Manuscript database

New waste management methods are needed that can protect the environment and allow manure management to switch back to a recycling view of manure handling. We investigated the use of gas-permeable membranes as components of new processes to capture and recover the ammonia in the liquid manures or in...

Ultra-thin Oxide Membranes: Synthesis and Carrier Transport

NASA Astrophysics Data System (ADS)

Sim, Jai Sung

Self-supported freestanding membranes are films that are devoid of any underlying supporting layers. The key advantage of such structures is that, due to the lack of substrate effects - both mechanical and chemical, the true native properties of the material can be probed. This is crucial since many of the studies done on materials that are used as freestanding membranes are done as films clamped to substrates or in the bulk form. This thesis focuses on the synthesis and fabrication as well as electrical studies of free standing ultrathin < 40nm oxide membranes. It also is one of the first demonstrations for electrically probing nanoscale freestanding oxide membranes. Fabrication of such membranes is non-trivial as oxide materials are often brittle and difficult to handle. Therefore, it requires an understanding of thin plate mechanics coupled with controllable thin film deposition process. Taking things a step further, to electrically probe these membranes required design of complex device architecture and extensive optimization of nano-fabrication processes. The challenges and optimized fabrication method of such membranes are demonstrated. Three materials are probed in this study, VO2, TiO2, and CeO2. VO2 for understanding structural considerations for electronic phase change and nature of ionic liquid gating, TiO2 and CeO2 for understanding surface conduction properties and surface chemistry. The VO2 study shows shift in metal-insulator transition (MIT) temperature arising from stress relaxation and opening of the hysteresis. The ionic liquid gating studies showed reversible modulation of channel resistance and allowed distinguishing bulk process from the surface effects. Comparing the ionic liquid gating experiments to hydrogen doping experiments illustrated that ionic liquid gating can be a surface limited electrostatic effect, if the critical voltage threshold is not exceeded. TiO2 study shows creation of non-stoichiometric forms under ion milling. Utilizing focused ion beam milling, thin membranes of Ti xOy of 100-300 nm thickness have been created. TEM studies indicated polycrystallinity and presence of twins in the FIB-milled nanowalls. Compositional analysis in the transmission electron microscope also showed reduced content of oxygen, confirming non-stoichiometry. Temperature dependence of the electrical resistivity of the nanowall showed semiconducting behavior with an activation energy different from that of TiO2 single crystals and was attributed to formation of TinO2n-1 phases after FIB processing. The CeO2 study involved high temperature conductivity studies on substrate-free self-supported nano-crystalline ceria membranes up to 800 K. Increasing conductivity with oxygen partial pressure directly opposing the behavior of thin film devices 'clamped' by substrate has been observed. This illustrate that the relaxed nature of free standing membranes, and increased surface to volume ratio enables more sensitive electrical response to oxygen adsorption which could have implications for their use in oxygen storage devices, solid oxide fuel cells, and chemical sensors. The work in this thesis advances the understanding of materials in freestanding membrane form and advances fabrication techniques that have not been explored before, having implications for sensors, actuators, SOFC, memristors, and physics of quasi-2D materials.

Liquid-phase and vapor-phase dehydration of organic/water solutions

DOEpatents

Huang, Yu [Palo Alto, CA; Ly, Jennifer [San Jose, CA; Aldajani, Tiem [San Jose, CA; Baker, Richard W [Palo Alto, CA

2011-08-23

Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

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

NASA Technical Reports Server (NTRS)

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

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.

Process for Encapsulating Protein Crystals

NASA Technical Reports Server (NTRS)

Morrison, Dennis R.; Mosier, Benjamin

2003-01-01

A process for growing protein crystals encapsulated within membranes has been invented. This process begins with the encapsulation of a nearly saturated aqueous protein solution inside semipermeable membranes to form microcapsules. The encapsulation is effected by use of special formulations of a dissolved protein and a surfactant in an aqueous first liquid phase, which is placed into contact with a second, immiscible liquid phase that contains one or more polymers that are insoluble in the first phase. The second phase becomes formed into the semipermeable membranes that surround microglobules of the first phase, thereby forming the microcapsules. Once formed, the microcapsules are then dehydrated osmotically by exposure to a concentrated salt or polymer solution. The dehydration forms supersaturated solutions inside the microcapsules, thereby enabling nucleation and growth of protein crystals inside the microcapsules. By suitable formulation of the polymer or salt solution and of other physical and chemical parameters, one can control the rate of transport of water out of the microcapsules through the membranes and thereby create physicochemical conditions that favor the growth, within each microcapsule, of one or a few large crystals suitable for analysis by x-ray diffraction. The membrane polymer can be formulated to consist of low-molecular-weight molecules that do not interfere with the x-ray diffraction analysis of the encapsulated crystals. During dehydration, an electrostatic field can be applied to exert additional control over the rate of dehydration. This protein-crystal-encapsulation process is expected to constitute the basis of protein-growth experiments to be performed on the space shuttle and the International Space Station. As envisioned, the experiments would involve the exposure of immiscible liquids to each other in sequences of steps under microgravitational conditions. The experiments are expected to contribute to knowledge of the precise conditions under which protein crystals form. By enhancing the ability to grow crystals suitable for x-ray diffraction analysis, this knowledge can be expected to benefit not only the space program but also medicine and the pharmaceutical industry.

[Effect of ozone on membrane fouling in water and wastewater treatment: a research review].

PubMed

Zhu, Hong-tao; Wen, Xiang-hua; Huang, Xia

2009-01-01

As a high efficient water and wastewater treatment technology, membrane filtration has been mainly used in wastewater treatment as membrane bioreactor, in reclaiming secondary effluent,treating surface water and potable water, and etc. Membrane fouling is a main obstacle to the wide application of membrane technology. Ozone has strong oxidizing power and has been utilized widely in water and wastewater treatment. In recent years, researches on combined process of ozone-membrane filtration are increasing. This paper does reviews and analysis of these researches. It is noticed that there has been a few of researches on the ozone treatment plus MBR process. Pre-ozonation of feed to MBR and slight ozonation of the mixed liquid in MBR may be used to relieve membrane fouling.Combined processes of ozone-membrane filtration can be divided into three classes in terms of the function of ozone and the system configuration: (1) cleaning the fouled membrane with ozone; (2) separate ozone-membrane filtration process; (3) integrated ozone-membrane filtration process. Although most reports supported that ozonation can control membrane fouling development,there were contrary results. At present, researches on the mechanisms of ozone's effect on membrane fouling control concentrated on the change of organic composition of the filtration influent under ozonation, however, particulate substances, microbial and inorganic substances may also be affected and then play roles in membrane fouling, depending on source water quality and process configuration. Moreover, there have not been common parameters to evaluate the ozone diffusion equipment and efficiency. The authors suggest that further researches should emphasize on integrated ozone-membrane process, and more attention should be paid to the cost-effectiveness of the combined process.

Preparation and blood compatibility of polysiloxane/liquid-crystal composite membranes.

PubMed

Li, L; Tu, M; Mou, S; Zhou, C

2001-10-01

Polysiloxane/liquid crystal composite membrane was first suggested to be used as biomaterials. In this work, the polydimethyl-methylhydrosiloxane and polydimethyl-methylethylenesilosiane, as a substrate, were blended with cholesteryl oleyl carbonate (COC) in tetrahydrofuran, and then crosslinked into membranes on glass plates by means of the platinum catalyst at 110 degrees C for 20 min. The effects of the liquid-crystal content in composite membranes on the formation of liquid-crystal phase were verified by the observation of optical polarization microscopy. The relationship between the morphology of the composite membranes and blood compatibility was identified by the dynamic blood-clotting tests, haemolysis ratio measurement, platelet adhesion and SEM observation. The results show that the blood-compatibility of composite membranes with the concentration of liquid crystal 20, 30% (wt) is more excellent than that of other composite membranes.

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

PubMed

Bader, M S H

2005-05-20

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

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.

Method and apparatus for determining the hydraulic conductivity of earthen material

DOEpatents

Sisson, James B.; Honeycutt, Thomas K.; Hubbell, Joel M.

1996-01-01

An earthen material hydraulic conductivity determining apparatus includes, a) a semipermeable membrane having a fore earthen material bearing surface and an opposing rear liquid receiving surface; b) a pump in fluid communication with the semipermeable membrane rear surface, the pump being capable of delivering liquid to the membrane rear surface at a plurality of selected variable flow rates or at a plurality of selected variable pressures; c) a liquid reservoir in fluid communication with the pump, the liquid reservoir retaining a liquid for pumping to the membrane rear surface; and d) a pressure sensor in fluid communication with the membrane rear surface to measure pressure of liquid delivered to the membrane by the pump. Preferably, the pump comprises a pair of longitudinally opposed and aligned syringes which are operable to simultaneously fill one syringe while emptying the other. Methods of determining the hydraulic conductivity of earthen material are also disclosed.

Method and apparatus for determining the hydraulic conductivity of earthen material

DOEpatents

Sisson, J.B.; Honeycutt, T.K.; Hubbell, J.M.

1996-05-28

An earthen material hydraulic conductivity determining apparatus includes: (a) a semipermeable membrane having a fore earthen material bearing surface and an opposing rear liquid receiving surface; (b) a pump in fluid communication with the semipermeable membrane rear surface, the pump being capable of delivering liquid to the membrane rear surface at a plurality of selected variable flow rates or at a plurality of selected variable pressures; (c) a liquid reservoir in fluid communication with the pump, the liquid reservoir retaining a liquid for pumping to the membrane rear surface; and (d) a pressure sensor in fluid communication with the membrane rear surface to measure pressure of liquid delivered to the membrane by the pump. Preferably, the pump comprises a pair of longitudinally opposed and aligned syringes which are operable to simultaneously fill one syringe while emptying the other. Methods of determining the hydraulic conductivity of earthen material are also disclosed. 15 figs.

The ecological impact of membrane-based extraction of phenolic compounds--a life cycle assessment study.

PubMed

Bayer, C; Follmann, M; Melin, T; Wintgens, T; Larsson, K; Almemark, M

2010-01-01

Many phenolic compounds show high boiling points, low molecular weights, moderate polarities or high toxicities. Therefore, conventional wastewater treatment is limited or expensive. Recycling of the separated compounds is often not possible. But, if liquid-liquid reactive extraction is linked to a non-porous membrane, some or all of the above mentioned limitations may be overcome. The key element is a composite membrane with a dense, hydrophobic top layer which avoids the mixing of the two aqueous fluid streams. The dilute phenol stream is one of them, the other is caustic soda as stripping solvent. Since the basics of this technology have been discussed before, the scope of this study is to facilitate process implementation and integration. To this end, a life cycle assessment framework is used to identify the optimal equipment size for the treatment of wastewater that may, for example, originate from the production of polycarbonate. Limiting for this application is not the environmental performance though, but most likely process economics.

Process for analyzing CO.sub.2 in seawater

DOEpatents

Atwater, James E.; Akse, James R.; DeHart, Jeffrey

1997-01-01

The process of this invention comprises providing a membrane for separating CO.sub.2 into a first CO.sub.2 sample phase and a second CO.sub.2 analyte phase. CO.sub.2 is then transported through the membrane thereby separating the CO.sub.2 with the membrane into a first CO.sub.2 sample phase and a second CO.sub.2 analyte liquid phase including an ionized, conductive, dissociated CO.sub.2 species. Next, the concentration of the ionized, conductive, dissociated CO.sub.2 species in the second CO.sub.2 analyte liquid phase is chemically amplified using a water-soluble chemical reagent which reversibly reacts with undissociated CO.sub.2 to produce conductivity changes therein corresponding to fluctuations in the partial pressure of CO.sub.2 in the first CO.sub.2 sample phase. Finally, the chemically amplified, ionized, conductive, dissociated CO.sub.2 species is introduced to a conductivity measuring instrument. Conductivity changes in the chemically amplified, ionized, conductive, dissociated CO.sub.2 species are detected using the conductivity measuring instrument.

Design of a liquid membrane target for high repetition rate neutron generation

NASA Astrophysics Data System (ADS)

Poole, Patrick; Andereck, C. David; Storm, Mike; Schumacher, Douglass

2013-10-01

Ultra-bright, pulsed, spatially-small sources of energetic neutrons have applications in radiography and non-destructive remote sensing. Neutrons can be generated by a process wherein ions accelerated from a laser-irradiated primary target subsequently bombard a converter material, causing neutron-producing nuclear reactions, such as 7Li(d,n)8Be. Deuterons from this process are suppressed by contamination that builds up on the rear of the solid primary target. To eliminate this issue we propose a self-replenishing liquid membrane target consisting of heavy water and deuterated surfactant, formed in-vacuum within a moveable wire frame. In addition to removing issues associated with solid target positioning and collateral damage, this apparatus provides flow rate and target thickness control, and allows for the high repetition rates required to generate desired neutron fluxes with a portable laser-based system. The apparatus design will be presented, as well as a novel interferometric method that measures the membrane thickness using tightly-focused light. This work was performed with support from DARPA.

Room-temperature ionic liquids and composite materials: platform technologies for CO(2) capture.

PubMed

Bara, Jason E; Camper, Dean E; Gin, Douglas L; Noble, Richard D

2010-01-19

Clean energy production has become one of the most prominent global issues of the early 21st century, prompting social, economic, and scientific debates regarding energy usage, energy sources, and sustainable energy strategies. The reduction of greenhouse gas emissions, specifically carbon dioxide (CO(2)), figures prominently in the discussions on the future of global energy policy. Billions of tons of annual CO(2) emissions are the direct result of fossil fuel combustion to generate electricity. Producing clean energy from abundant sources such as coal will require a massive infrastructure and highly efficient capture technologies to curb CO(2) emissions. Current technologies for CO(2) removal from other gases, such as those used in natural gas sweetening, are also capable of capturing CO(2) from power plant emissions. Aqueous amine processes are found in the vast majority of natural gas sweetening operations in the United States. However, conventional aqueous amine processes are highly energy intensive; their implementation for postcombustion CO(2) capture from power plant emissions would drastically cut plant output and efficiency. Membranes, another technology used in natural gas sweetening, have been proposed as an alternative mechanism for CO(2) capture from flue gas. Although membranes offer a potentially less energy-intensive approach, their development and industrial implementation lags far behind that of amine processes. Thus, to minimize the impact of postcombustion CO(2) capture on the economics of energy production, advances are needed in both of these areas. In this Account, we review our recent research devoted to absorptive processes and membranes. Specifically, we have explored the use of room-temperature ionic liquids (RTILs) in absorptive and membrane technologies for CO(2) capture. RTILs present a highly versatile and tunable platform for the development of new processes and materials aimed at the capture of CO(2) from power plant flue gas and in natural gas sweetening. The desirable properties of RTIL solvents, such as negligible vapor pressures, thermal stability, and a large liquid range, make them interesting candidates as new materials in well-known CO(2) capture processes. Here, we focus on the use of RTILs (1) as absorbents, including in combination with amines, and (2) in the design of polymer membranes. RTIL amine solvents have many potential advantages over aqueous amines, and the versatile chemistry of imidazolium-based RTILs also allows for the generation of new types of CO(2)-selective polymer membranes. RTIL and RTIL-based composites can compete with, or improve upon, current technologies. Moreover, owing to our experience in this area, we are developing new imidazolium-based polymer architectures and thermotropic and lyotropic liquid crystals as highly tailorable materials based on and capable of interacting with RTILs.

GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Howard S. Meyer

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 inmore » 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 HazOp review was conducted. Potting and module materials testing continued. Preliminary design of the bench-scale equipment continues. A status meeting was held in Morgantown, WV with the DOE Project Manager.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yulaev, Alexander; Guo, Hongxuan; Strelcov, Evgheni

Atomic-scale thickness, molecular impermeability, low atomic number, and mechanical strength make graphene an ideal electron-transparent membrane for material characterization in liquids and gases with scanning electron microscopy and spectroscopy. Here in this paper, we present a novel sample platform made of an array of thousands of identical isolated graphene-capped microchannels with high aspect ratio. A combination of a global wide field of view with high resolution local imaging of the array allows for high throughput in situ studies as well as for combinatorial screening of solutions, liquid interfaces, and immersed samples. We demonstrate the capabilities of this platform by studyingmore » a pure water sample in comparison with alkali halide solutions, a model electrochemical plating process, and beam-induced crystal growth in liquid electrolyte. Spectroscopic characterization of liquid interfaces and immersed objects with Auger and X-ray fluorescence analysis through the graphene membrane are also demonstrated.« less

(NH4)2SO4 recovery from liquid side streams.

PubMed

Boehler, Marc Anton; Heisele, Alexander; Seyfried, Alexander; Grömping, Markus; Siegrist, Hansruedi

2015-05-01

Two methods of recovering nitrogen from liquid side streams are presented in this paper. The first method was demonstrated at an ammonia stripping plant treating 5-7 m(3)/h sludge water at the wastewater treatment plant (WWTP) Kloten-Opfikon (CH). In addition to the usual stripping and scrubbing columns, a third column had been added in order strip CO₂, thus reducing the NaOH-demand of the subsequent ammonia stripping. At first, just the stripping plant was put into operation and optimized without any pre-treatment of the supernatant. Next, the CO₂-stripper column was activated and optimized by gas measurements to minimize free ammonia losses, heat losses, and energy consumption. Key operational aspects of the plant were evaluated. Finally, up to 1.4 m(3)/h source-separated urine was successfully fed into the stripping facility. The second ammonia removal method using hydrophobic hollow fiber membranes was tested in two small pilot systems by different manufacturers in 2012 and 2013 at WWTP Neugut. In this technology, free ammonia gas in the sludge liquid diffuses at pH >9.3 from the sludge liquid through the air-filled pores of the microporous hydrophobic membrane into concentrated sulfuric acid flowing through the hollow fibers, forming ammonium sulfate. The small pore size and the hydrophobic nature of the membrane prevent the liquid phase from entering into the pores due to the surface tension effect. Practical experience regarding operational parameters like wastewater flow rate, pH, temperature, ammonia concentration, fouling and precipitations processes, optimal flow schemes, and process configurations was collected.

SEPARATION OF VAPOR-PHASE ALCOHOL/WATER MIXTURES VIA FRACTIONAL CONDENSATION USING A PILOT-SCALE DEPHLEGMATOR: ENHANCEMENT OF THE PREVAPORATION PROCESS SEPARATION FACTOR

EPA Science Inventory

In prevaporation, a liquid mixture contacts a membrane surface that preferentially permeates one of the liquid components as a vapor. Our approach to improving pervaporation performance is to replace the one-stage condenser traditionally used to condense the permeate with a frac...

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.

Supported mesoporous carbon ultrafiltration membrane and process for making the same

DOEpatents

Strano, Michael; Foley, Henry C.; Agarwal, Hans

2004-04-13

A novel supported mesoporous carbon ultrafiltration membrane and process for producing the same. The membranes comprise a mesoporous carbon layer that exists both within and external to the porous support. A liquid polymer precursor composition comprising both carbonizing and noncarbonizing templating polymers is deposited on the porous metal support. The coated support is then heated in an inert-gas atmosphere to pyrolyze the polymeric precursor and form a mesoporous carbon layer on and within the support. The pore-size of the membranes is dependent on the molecular weight of the noncarbonizing templating polymer precursor. The mesoporous carbon layer is stable and can withstand high temperatures and exposure to organic chemicals. Additionally, the porous metal support provides excellent strength properties. The composite structure of the membrane provides novel structural properties and allows for increased operating pressures allowing for greater membrane flow rates. The invention also relates to the use of the novel ultrafiltration membrane to separate macromolecules from solution. An example is shown separating bovine serum albumin from water. The membrane functions by separating and by selective adsorption. Because of the membrane's porous metal support, it is well suited to industrial applications. The unique properties of the supported mesoporous carbon membrane also allow the membrane to be used in transient pressure or temperature swing separations processes. Such processes were not previously possible with existing mesoporous membranes. The present invention, however, possesses the requisite physical properties to perform such novel ultrafiltration processes.

Increase The Sugar Concentration of The Solution Sugar by Reverse Osmotic Membrane

NASA Astrophysics Data System (ADS)

Redjeki, S.; Hapsari, N.; Iriani

2018-01-01

Sugar is one of the basic needs of people and food and drink industry. As technology advances and the demand for efficient usage of sugar rises, crystal sugar is seen as less advantageous than liquid sugar. If sugar is always dissolved in water before use, then it will be more efficient and practical for consumers to use sugar in liquid form than in crystal form. Other than that, liquid sugar is also attractive to consumers because it is economical, hygienic, instantly soluble in hot and cold water, fresher and longer-lasting, able to thicken and enrich the texture of foods and drinks, and functions as sweetener, syrup, and flavor enhancer. Liquid sugar is also more beneficial for sugar producers because of simpler production process, cheaper production cost, and similar yield with no extra cost. In sugar production, separation process is found in most of its stages and therefore the use of membrane technology for separating solute and water content has a good potential. In this research, water content reduction of sugar solution was done in order to increase the sugar concentration of the solution. The parameters of this research were 4%, 5%, and 6% starting concentration of sugar solution; 20, 40, and 60 minutes of process time; and 85 and 60 PSI ΔP. The best result was acquired on 4% starting concentration, 60 PSI ΔP, and 60 minutes process time.

Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

PubMed

Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

2012-08-07

To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance.

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.

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)

Supplemental effect of different levels of taurine in Modena on boar semen quality during liquid preservation at 17°C.

PubMed

Li, Hao; Zhang, Xiao-Gang; Fang, Qian; Liu, Qi; Du, Ren-Rang; Yang, Gong-She; Wang, Li-Qiang; Hu, Jian-Hong

2017-11-01

Peroxidation damage induces sublethal injury to boar sperm during the storage process. Taurine has already been demonstrated to protect cells effectively from oxidant-induced injury. This study was aimed to evaluate the effect of different concentrations of taurine (0.5, 1, 5 and 10 mmol/L) in Modena diluent on boar sperm quality during liquid storage at 17°C. Ejaculates from sexually mature Duroc pigs were collected, pooled and preserved in the Modena containing different concentrations of taurine. Sperm motility, plasma membrane integrity, acrosome integrity, total antioxidative capacity (T-AOC) activity and malondialdehyde content (MDA) were examined every 24 h. Modena diluent containing taurine suppressed the reduction in sperm qualities during the process of liquid preservation compared with those of the control group. After 5 days of liquid preservation, the addition of taurine at 5 mmol/L had the optimal effect on survival time as well as maintenance of motility, plasma membrane integrity, acrosomal integrity, T-AOC activity and MDA content. These results may suggest the possibility that the proper addition of taurine to the semen extender improves the swine production system using artificial insemination by the suppressing of sperm damage and subsequent dysfunction during liquid preservation. © 2017 Japanese Society of Animal Science.

Recovery of ammonia from poultry litter using flat gas permeable membranes.

PubMed

Rothrock, M J; Szögi, A A; Vanotti, M B

2013-06-01

The use of flat gas-permeable membranes was investigated as components of a new process to capture and recover ammonia (NH3) in poultry houses. This process includes the passage of gaseous NH3 through a microporous hydrophobic membrane, capture with a circulating dilute acid on the other side of the membrane, and production of a concentrated ammonium (NH4) salt. Bench- and pilot-scale prototype systems using flat expanded polytetrafluoroethylene (ePTFE) membranes and a sulfuric acid solution consistently reduced headspace NH3 concentrations from 70% to 97% and recovered 88% to 100% of the NH3 volatilized from poultry litter. The potential benefits of this technology include cleaner air inside poultry houses, reduced ventilation costs, and a concentrated liquid ammonium salt that can be used as a plant nutrient solution. Published by Elsevier Ltd.

Post-thaw sperm characteristics following long-term storage of boar semen in liquid nitrogen.

PubMed

Fraser, L; Strzeżek, J; Kordan, W

2014-06-30

This study investigated the effect of long-term liquid nitrogen storage of semen from individual boars on post-thaw sperm characteristics. Ejaculates, collected from five Polish large white (PLW) and five Polish landrace (PLR) boars, were frozen using a standard cryopreservation protocol. Post-thaw analysis was performed within a week (Period 1) and 42-48 months (Period 2) of semen storage in liquid nitrogen. Post-thaw sperm assessments included total motility, mitochondrial function (JC-1/PI assay), plasma membrane integrity (SYBR-14/PI assay), osmotic resistance test (ORT), lipid peroxidation (LPO) status and DNA fragmentation, analysed by the neutral Comet assay. Individual boar variability within breed and cryostorage periods had significant effects on the analysed parameters of frozen-thawed spermatozoa. Prolonged semen storage in liquid nitrogen (Period 2) induced a marked reduction in post-thaw sperm motility, mitochondrial function and plasma membrane integrity in most of the boars. Post-thaw semen of eight boars exhibited a marked decrease in osmotic resistance of the sperm acrosomal membrane, whereas a significant increase in the sperm cryo-susceptibility to induced LPO and DNA fragmentation was observed only in three boars after long-term semen storage. Additionally, frozen-thawed spermatozoa of PLR boars exhibited significantly lower osmotic resistance of the acrosomal membrane than PLW boars following prolonged semen storage in liquid nitrogen. The results of this study provide evidence of ageing processes in frozen-thawed boar spermatozoa following prolonged cryostorage. It seems that, even though cryopreservation allows long-term semen storage in liquid nitrogen, spermatozoa from individual boars are more susceptible to cryo-induced damage. Copyright © 2014 Elsevier B.V. All rights reserved.

Nanofiltration in the manufacture of liquid dyes production.

PubMed

Mikulásek, P; Cuhorka, J

2010-01-01

In the manufacture of liquid dyes, almost complete desalting, which helps to improve the stability of the product, enhances the solubility of the dye. Diafiltration is used to allow a high level of desalting to be achieved. The process of desalination of aqueous dye-salt solutions by polymeric nanofiltration membranes using commercially available modules was studied. The influence of dye and salt concentration on the salt rejection and pressure applied on the flux as well as comparison of individual NF membranes for desalting purposes is presented. The great interest is also devoted to the mathematical modelling of nanofiltration and description of discontinuous diafiltration by periodically adding solvent at constant pressure difference.

[Germ cell membrane lipids in spermatogenesis].

PubMed

Wang, Ting; Shi, Xiao; Quan, Song

2016-05-01

Spermatogenesis is a complex developmental process in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. During spermatogenesis, membrane remodeling takes place, and cell membrane permeability and liquidity undergo phase-specific changes, which are all associated with the alteration of membrane lipids. Lipids are important components of the germ cell membrane, whose volume and ratio fluctuate in different phases of spermatogenesis. Abnormal lipid metabolism can cause spermatogenic dysfunction and consequently male infertility. Germ cell membrane lipids are mainly composed of cholesterol, phospholipids and glycolipids, which play critical roles in cell adhesion and signal transduction during spermatogenesis. An insight into the correlation of membrane lipids with spermatogenesis helps us to better understand the mechanisms of spermatogenesis and provide new approaches to the diagnosis and treatment of male infertility.

Influence of fermentation liquid from waste activated sludge on anoxic/oxic- membrane bioreactor performance: Nitrogen removal, membrane fouling and microbial community.

PubMed

Han, Xiaomeng; Zhou, Zhen; Mei, Xiaojie; Ma, Yan; Xie, Zhenfang

2018-02-01

In order to investigate effects of waste activated sludge (WAS) fermentation liquid on anoxic/oxic- membrane bioreactor (A/O-MBR), two A/O-MBRs with and without WAS fermentation liquid addition were operated in parallel. Results show that addition of WAS fermentation liquid clearly improved denitrification efficiency without deterioration of nitrification, while severe membrane fouling occurred. WAS fermentation liquid resulted in an elevated production of proteins and humic acids in bound extracellular polymeric substance (EPS) and release of organic matter with high MW fractions in soluble microbial product (SMP) and loosely bound EPS (LB-EPS). Measurement of deposition rate and fluid structure confirmed increased fouling potential of SMP and LB-EPS. γ-Proteobacteria and Ferruginibacter, which can secrete and export EPS, were also found to be abundant in the MBR with WAS fermentation liquid. It is implied that when WAS fermentation liquid was applied, some operational steps to control membrane fouling should be employed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Liquid metal electric pump

DOEpatents

Abbin, J.P.; Andraka, C.E.; Lukens, L.L.; Moreno, J.B.

1992-01-14

An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other. 3 figs.

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.

Membrane applications and research in food processing: An assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohr, C.M.; Leeper, S.A.; Engelau, D.E.

This assessment is intended to aid in planning separations research and development projects aimed at reducing energy consumption in the food industry. The food processing industry uses approximately 1.5 quadrillion Btu per year, 2% of the US national annual energy consumption. Food processing involves a variety of liquid feed, product, and waste streams and makes extensive use of thermal operations such as drying, evaporation, pasteurization, and distillation. As such, it is a candidate for energy conservation through the use of membrane separations. The assessment is organized according to Standard Industry Classification (SIC) Code for the food industry. Individual subindustries consideredmore » are: (a) Meat Processing, Dairy Products, Preserved Fruit and Vegetables, Grain Milling, Bakery Products, Sugar and Confectionery products, Edible Fats and Oils, and Beverages. Topics covered include: (a) background information on food processing and membrane separations, (b) a review of current and developing membrane separations for the food industry, (c) energy consumption and processes used in individual subindustries, (d) separations in the subindustries that could be augmented or replaced by membrane processes, (e) industry practices and market conditions that could affect adoption of new technologies, and (f) prioritized recommendations for DOE-OIP supported research to further use of membrane separations in the food industry. 435 refs.« less

From material science to avant-garde cuisine. The art of shaping liquids into spheres.

PubMed

Fu, Haohao; Liu, Yingzhe; Adrià, Ferran; Shao, Xueguang; Cai, Wensheng; Chipot, Christophe

2014-10-09

Employing avant-garde cuisine techniques, in particular sodium alginates, liquid food can be shaped into spheres, thereby conferring to the former original and sometimes unexpected forms and textures. To achieve this result, rational understanding of the science that underlies food physical chemistry is of paramount importance. In this contribution, the process of spherification is dissected for the first time at the atomic level by means of classical molecular dynamics simulations. Our results show that a thin membrane consisting of intertwined alginate chains forms in an aqueous solution containing calcium ions, thereby encapsulating in a sphere the aliment in its liquid state. They also show why the polysaccharide chains will not cohere into such a membrane in a solution of sodium ions. Analysis of the trajectories reveals the emergence of so-called egg-box spatial arrangements, which connect the alginate chains by means of repeated chelation of one calcium ion by two carboxylate groups. Free-energy calculations delineating the formation of these egg-box structures further illuminate the remarkable stability of such tridimensional organizations, which ensures at room temperature the spontaneous growth of the polysaccharide membrane. Spherification has been also examined for liquid aliments of different nature, modeled by charged, hydrophilic and hydrophobic compounds. The membrane-encapsulated food is shaped into robust and durable spheres, irrespective of the liquid core material. By reconciling the views of spherification at small and large scales, the present study lays the groundwork for the rational design of innovative cooking techniques relevant to avant-garde cuisine.

Separation of metals by supported liquid membrane

DOEpatents

Takigawa, Doreen Y.

1992-01-01

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

Effect of membrane and process characteristics on cost and energy usage for separating alcohol–water mixtures using a hybrid vapor stripping–vapor permeation process

EPA Science Inventory

BACKGROUND: Alcohols, including ethanol and butanol, are receiving increased attention as renewable liquid biofuels. Alcohol concentrations may be low in a biological process due to product inhibition and, for non-starch feedstocks, limited substrate concentrations. The result is...

Ionic-Liquid-Based CO2 Capture Systems: Structure, Interaction and Process.

PubMed

Zeng, Shaojuan; Zhang, Xiangping; Bai, Lu; Zhang, Xiaochun; Wang, Hui; Wang, Jianji; Bao, Di; Li, Mengdie; Liu, Xinyan; Zhang, Suojiang

2017-07-26

The inherent structure tunability, good affinity with CO 2 , and nonvolatility of ionic liquids (ILs) drive their exploration and exploitation in CO 2 separation field, and has attracted remarkable interest from both industries and academia. The aim of this Review is to give a detailed overview on the recent advances on IL-based materials, including pure ILs, IL-based solvents, and IL-based membranes for CO 2 capture and separation from the viewpoint of molecule to engineering. The effects of anions, cations and functional groups on CO 2 solubility and selectivity of ILs, as well as the studies on degradability of ILs are reviewed, and the recent developments on functionalized ILs, IL-based solvents, and IL-based membranes are also discussed. CO 2 separation mechanism with IL-based solvents and IL-based membranes are explained by combining molecular simulation and experimental characterization. Taking into consideration of the applications and industrialization, the recent achievements and developments on the transport properties of IL fluids and the process design of IL-based processes are highlighted. Finally, the future research challenges and perspectives of the commercialization of CO 2 capture and separation with IL-based materials are posed.

Membrane bioreactors' potential for ethanol and biogas production: a review.

PubMed

Ylitervo, Päivi; Akinbomia, Julius; Taherzadeha, Mohammad J

2013-01-01

Companies developing and producing membranes for different separation purposes, as well as the market for these, have markedly increased in numbers over the last decade. Membrane and separation technology might well contribute to making fuel ethanol and biogas production from lignocellulosic materials more economically viable and productive. Combining biological processes with membrane separation techniques in a membrane bioreactor (MBR) increases cell concentrations extensively in the bioreactor. Such a combination furthermore reduces product inhibition during the biological process, increases product concentration and productivity, and simplifies the separation of product and/or cells. Various MBRs have been studied over the years, where the membrane is either submerged inside the liquid to be filtered, or placed in an external loop outside the bioreactor. All configurations have advantages and drawbacks, as reviewed in this paper. The current review presents an account of the membrane separation technologies, and the research performed on MBRs, focusing on ethanol and biogas production. The advantages and potentials of the technology are elucidated.

Influence of gas-liquid two-phase flow on angiotensin-I converting enzyme inhibitory peptides separation by ultra-filtration.

PubMed

Charoenphun, Narin; Youravong, Wirote

2017-01-01

Membrane fouling is a major problem in ultra-filtration systems and two-phase flow is a promising technique for permeate flux enhancement. The objective of this research was to study the use of an ultra-filtration (UF) system to enrich angiotensin-I converting enzyme (ACE) inhibitory peptides from tilapia protein hydrolysate. To select the most appropriate membrane and operating condition, the effects of membrane molecular weight cut-off (MWCO), transmembrane pressure (TMP) and cross-flow velocity (CFV) on permeate flux and ACE inhibitory peptide separation were studied. Additionally, the gas-liquid two-phase flow technique was applied to investigate its effect on the process capability. The results showed that the highest ACE inhibitory activity was obtained from permeate of the 1 kDa membrane. In terms of TMP and CFV, the permeate flux tended to increase with TMP and CFV. The use of gas-liquid two-phase flow as indicated by shear stress number could reduce membrane fouling and increase the permeate flux up to 42%, depending on shear stress number. Moreover, the use of a shear stress number of 0.039 led to an augmentation in ACE inhibitory activity of permeates. Operating conditions using a shear stress number of 0.039 were recommended for enrichment of ACE inhibitory peptides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Linking Findings in Microfluidics to Membrane Emulsification Process Design: The Importance of Wettability and Component Interactions with Interfaces

PubMed Central

Schroën, Karin; Ferrando, Montse; de Lamo-Castellví, Silvia; Sahin, Sami; Güell, Carme

2016-01-01

In microfluidics and other microstructured devices, wettability changes, as a result of component interactions with the solid wall, can have dramatic effects. In emulsion separation and emulsification applications, the desired behavior can even be completely lost. Wettability changes also occur in one phase systems, but the effect is much more far-reaching when using two-phase systems. For microfluidic emulsification devices, this can be elegantly demonstrated and quantified for EDGE (Edge-base Droplet GEneration) devices that have a specific behavior that allows us to distinguish between surfactant and liquid interactions with the solid surface. Based on these findings, design rules can be defined for emulsification with any micro-structured emulsification device, such as direct and premix membrane emulsification. In general, it can be concluded that mostly surface interactions increase the contact angle toward 90°, either through the surfactant, or the oil that is used. This leads to poor process stability, and very limited pressure ranges at which small droplets can be made in microfluidic systems, and cross-flow membrane emulsification. In a limited number of cases, surface interactions can also lead to lower contact angles, thereby increasing the operational stability. This paper concludes with a guideline that can be used to come to the appropriate combination of membrane construction material (or any micro-structured device), surfactants and liquids, in combination with process conditions. PMID:27187484

Abstract - Cooperative Research and Development Agreement between Penn State University and National Energy Technology Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hickner, Michael A.; Matranga, Christopher S.

This project will use bipolar membranes to produce efficient vapor-phase electrolysis cells for splitting CO 2 to CO and oxygen. CO is a valuable chemical feedstock that can be combined catalytically with hydrogen in the Fischer-Tropsch process to make liquid fuels. CO is arguably the best target for CO 2 reduction since, as a gaseous product, it is easily collected and is relatively immune to membrane crossover losses. The keys to success in this project are to design and synthesize hydrophilic, low resistance bipolar membranes and to create optimized electrode/catalyst/ electrolyte architectures based on these new membranes and advanced catalystsmore » in order to achieve high current density at low overpotentials for CO 2 conversion. High current density is key to achieving industrially-relevant throughput for the process and low overpotentials maintain high overall efficiency for the process.« less

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...

Plasma treatment of polyethersulfone membrane for benzene removal from water by air gap membrane distillation.

PubMed

Pedram, Sara; Mortaheb, Hamid Reza; Arefi-Khonsari, Farzaneh

2018-01-01

In order to obtain a durable cost-effective membrane for membrane distillation (MD) process, flat sheet polyethersulfone (PES) membranes were modified by an atmospheric pressure nonequilibrium plasma generated using a dielectric barrier discharge in a mixture of argon and hexamethyldisiloxane as the organosilicon precursor. The surface properties of the plasma-modified membranes were characterized by water contact angle (CA), liquid entry pressure, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water CA of the membrane was increased from 64° to 104° by depositing a Si(CH 3 )-rich thin layer. While the pristine PES membrane was not applicable in the MD process, the modified PES membrane could be applied for the first time in an air gap membrane distillation setup for the removal of benzene as a volatile organic compound from water. The experimental design using central composite design and response surface methodology was applied to study the effects of feed temperature, concentration, and flow rate as well as their binary interactions on the overall permeate flux and separation factor. The separation factor and permeation flux of the modified PES membrane at optimum conditions were comparable with those of commercial polytetrafluoroethylene membrane.

Engineering lipid structure for recognition of the liquid ordered membrane phase

DOE PAGES

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

2016-08-26

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

Engineering Lipid Structure for Recognition of the Liquid Ordered Membrane Phase.

PubMed

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

2016-11-29

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

Micro-Raman spectroscopy study of the effect of Mid-Ultraviolet radiation on erythrocyte membrane.

PubMed

Li, N; Li, S X; Guo, Z Y; Zhuang, Z F; Li, R; Xiong, K; Chen, S J; Liu, S H

2012-07-02

Mid-Ultraviolet (UVB) has a significant influence on human health. In this study, human erythrocytes were exposed to UVB to investigate the effects of UVB radiation on erythrocytes membrane. And Micro-Raman spectroscopy was employed to detect the damage. Principal component analysis (PCA) was used to classify the control erythrocytes and the irradiated erythrocytes. Results showed that the erythrocytes membrane was damaged by Mid-Ultraviolet (UVB) radiation. The intensity of the Raman peaks at 1126 cm(-1) and 1082 cm(-1) were used to calculate the Longitudinal Order-Parameters in Chains (S(trans)) which can present the liquidity and ionic permeability of erythrocyte membrane. After UVB radiation for 30 min, both the liquidity and ionic permeability decreased. At the same time, the intensity of the peaks at 1302 cm(-1) (α-helix), 1254 cm(-1) (random coil), 1452 cm(-1) and 1430 cm(-1) (CH(2)/CH(3) stretch) have also changed which indicated the membrane protein also been damaged by UVB. In the whole process of radiation, the more UVB radiation dose the more damage on the erythrocyte membrane. Copyright © 2012 Elsevier B.V. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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

2012-08-01

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

The Need for a Kinetics for Biological Transport

PubMed Central

Schindler, A. M.; Iberall, A. S.

1973-01-01

The traditional theory of transport across capillary membranes via a laminar Poiseuille flow is shown to be invalid. It is demonstrated that the random, diffusive nature of the molecular flow and interactions with the “pore” walls play an important role in the transport process. Neither the continuum Navier-Stokes theory nor the equivalent theory of irreversible thermodynamics is adequate to treat the problem. Combination of near-continuum hydrodynamic theory, noncontinuum kinetic theory, and the theory of fluctuations provides a first step toward modeling both liquid processes in general and membrane transport processes as a specific application. PMID:4726880

Giant plasma membrane vesicles: models for understanding membrane organization.

PubMed

Levental, Kandice R; Levental, Ilya

2015-01-01

The organization of eukaryotic membranes into functional domains continues to fascinate and puzzle cell biologists and biophysicists. The lipid raft hypothesis proposes that collective lipid interactions compartmentalize the membrane into coexisting liquid domains that are central to membrane physiology. This hypothesis has proven controversial because such structures cannot be directly visualized in live cells by light microscopy. The recent observations of liquid-liquid phase separation in biological membranes are an important validation of the raft hypothesis and enable application of the experimental toolbox of membrane physics to a biologically complex phase-separated membrane. This review addresses the role of giant plasma membrane vesicles (GPMVs) in refining the raft hypothesis and expands on the application of GPMVs as an experimental model to answer some of key outstanding problems in membrane biology. Copyright © 2015 Elsevier Inc. All rights reserved.

Fabricating PFPE Membranes for Capillary Electrophoresis

NASA Technical Reports Server (NTRS)

Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason

2009-01-01

A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

Process for analyzing CO[sub 2] in air and in water

DOEpatents

Atwater, J.E.; Akse, J.R.; DeHart, J.

1999-06-08

The process of this invention comprises providing a membrane for separating CO[sub 2] into a first CO[sub 2] sample phase and a second CO[sub 2] analyte phase. CO[sub 2] is then transported through the membrane thereby separating the CO[sub 2] with the membrane into a first CO[sub 2] sample phase and a second CO[sub 2] analyte liquid phase including an ionized, conductive, dissociated CO[sub 2] species. Next, the concentration of the ionized, conductive, dissociated CO[sub 2] species in the second CO[sub 2] analyte liquid phase is chemically amplified using a water-soluble chemical reagent which reversibly reacts with undissociated CO[sub 2] to produce conductivity changes therein corresponding to fluctuations in the partial pressure of CO[sub 2] in the first CO[sub 2] sample phase. Finally, the chemically amplified, ionized, conductive, dissociated CO[sub 2] species is introduced to a conductivity measuring instrument. Conductivity changes in the chemically amplified, ionized, conductive, dissociated CO[sub 2] species are detected using the conductivity measuring instrument. 43 figs.

Process for analyzing CO.sub.2 in air and in water

DOEpatents

Atwater, James E.; Akse, James R.; DeHart, Jeffrey

1999-01-01

The process of this invention comprises providing a membrane for separating CO.sub.2 into a first CO.sub.2 sample phase and a second CO.sub.2 analyte phase. CO.sub.2 is then transported through the membrane thereby separating the CO.sub.2 with the membrane into a first CO.sub.2 sample phase and a second CO.sub.2 analyte liquid phase including an ionized, conductive, dissociated CO.sub.2 species. Next, the concentration of the ionized, conductive, dissociated CO.sub.2 species in the second CO.sub.2 analyte liquid phase is chemically amplified using a water-soluble chemical reagent which reversibly reacts with undissociated CO.sub.2 to produce conductivity changes therein corresponding to fluctuations in the partial pressure of CO.sub.2 in the first CO.sub.2 sample phase. Finally, the chemically amplified, ionized, conductive, dissociated CO.sub.2 species is introduced to a conductivity measuring instrument. Conductivity changes in the chemically amplified, ionized, conductive, dissociated CO.sub.2 species are detected using the conductivity measuring instrument.

Process for analyzing CO{sub 2} in seawater

DOEpatents

Atwater, J.E.; Akse, J.R.; DeHart, J.

1997-07-01

The process of this invention comprises providing a membrane for separating CO{sub 2} into a first CO{sub 2} sample phase and a second CO{sub 2} analyte phase. CO{sub 2} is then transported through the membrane thereby separating the CO{sub 2} with the membrane into a first CO{sub 2} sample phase and a second CO{sub 2} analyte liquid phase including an ionized, conductive, dissociated CO{sub 2} species. Next, the concentration of the ionized, conductive, dissociated CO{sub 2} species in the second CO{sub 2} analyte liquid phase is chemically amplified using a water-soluble chemical reagent which reversibly reacts with undissociated CO{sub 2} to produce conductivity changes therein corresponding to fluctuations in the partial pressure of CO{sub 2} in the first CO{sub 2} sample phase. Finally, the chemically amplified, ionized, conductive, dissociated CO{sub 2} species is introduced to a conductivity measuring instrument. Conductivity changes in the chemically amplified, ionized, conductive, dissociated CO{sub 2} species are detected using the conductivity measuring instrument. 43 figs.

Emergence of polysaccharide membrane walls through macro-space partitioning via interfacial instability.

PubMed

Okeyoshi, Kosuke; Okajima, Maiko K; Kaneko, Tatsuo

2017-07-21

Living organisms in drying environments build anisotropic structures and exhibit directionality through self-organization of biopolymers. However, the process of macro-scale assembly is still unknown. Here, we introduce a dissipative structure through a non-equilibrium process between hydration and deposition in the drying of a polysaccharide liquid crystalline solution. By controlling the geometries of the evaporation front in a limited space, multiple nuclei emerge to grow vertical membrane walls with macroscopic orientation. Notably, the membranes are formed through rational orientation of rod-like microassemblies along the dynamic three-phase contact line. Additionally, in the non-equilibrium state, a dissipative structure is ultimately immobilized as a macroscopically partitioned space by multiple vertical membranes. We foresee that such oriented membranes will be applicable to soft biomaterials with direction controllability, and the macroscopic space partitionings will aid in the understanding of the space recognition ability of natural products under drying environments.

Membrane alternatives in worlds without oxygen: Creation of an azotosome.

PubMed

Stevenson, James; Lunine, Jonathan; Clancy, Paulette

2015-02-01

The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water. This fact has caused astronomers who seek conditions suitable for life to search for exoplanets within the "habitable zone," the narrow band in which liquid water can exist. However, can cell membranes be created and function at temperatures far below those at which water is a liquid? We take a step toward answering this question by proposing a new type of membrane, composed of small organic nitrogen compounds, that is capable of forming and functioning in liquid methane at cryogenic temperatures. Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature. As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface.

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.

Chemical microreactor and method thereof

DOEpatents

Morse, Jeffrey D.; Jankowski, Alan

2005-11-01

A chemical microreactor suitable for generation of hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. One such microreactor employs a packed catalyst capillary microchannel and at least one porous membrane. Another employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2 /cm.sup.3. The packed catalyst capillary microchannels, porous membranes and porous membrane support structures may be formed by a variety of methods.

Performance of cellulose acetate membrane with different additives for palm oil mill effluent (POME) liquid waste treatment

NASA Astrophysics Data System (ADS)

Aprilia, N. A. S.; Fauzi; Azmi, N.; Najwan, N.; Amin, A.

2018-03-01

Performance of cellulose acetate membrane for treatment of POME liquid has studied with different additives. Cellulose acetate membranes were prepared with different additive ie formamide and polyethylene glycol and used acetone as solvent. The function of formamide and polyethylene glycol (PEG) is to increase the porosity of the membrane surface. Performance of the membrane were included SEM, FT-IR and coefficient permeability. Membrane performance has been performed for percent rejection of total suspended solid (TSS) and turbidity of POME liquid waste. Cellulose acetate with formamide shows an increased percentage of rejection in removing TSS and turbidity than cellulose acetate with PEG.

Demonstration Bulletin. Membrane Microfiltration. E. I. DuPont de Nemours and Company, Inc. Oberlin Filter Company

EPA Science Inventory

The DuPont/Oberlin microfiltration technology is a physical separation process that removes solid particles from liquid wastes. The process can filter particles that are submicron or larger in diameter. Pretreatment, such as chemical additions, will be required if dissolved con...

Three-phase molecularly imprinted sol-gel based hollow fiber liquid-phase microextraction combined with liquid chromatography-tandem mass spectrometry for enrichment and selective determination of a tentative lung cancer biomarker.

PubMed

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

2015-07-15

In the present study, the modification of a polysulfone hollow fiber membrane with in situ molecularly imprinted sol-gel process (as a novel and one-step method) was prepared and investigated. 3-(propylmethacrylate)trimethoxysilane (3PMTMOS) as an inorganic precursor was used for preparation of molecularly imprinted sol-gel. The modified molecularly imprinted sol-gel hollow fiber membrane (MSHM) was used for the liquid-phase microextraction (LPME) of hippuric acid (HA) in human plasma and urine samples. MSHM as a selective, robust, and durable tool was used for at least 50 extractions without significant decrease in the extraction efficiency. The non-molecularly imprinted sol-gel hollow fiber membrane (NSHM) as blank hollow fiber membrane was prepared by the same process, only without HA. To achieve the best condition, influential parameters on the extraction efficiency were thoroughly investigated. The capability of this robust, green, and simple method for extraction of HA was successfully accomplished with LC/MS/MS. The limits of detection (LOD) and quantification (LOQ) in human plasma and urine samples were 0.3 and 1.0nmolL(-1), respectively. The standard calibration curves were obtained within the concentration range 1-2000nmolL(-1) for HA in human plasma and urine. The coefficients of determination (r(2)) were ≥0.998. The obtained data exhibited recoveries were higher than 89% for the extraction of HA in human plasma and urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Liquid membrane purification of biogas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majumdar, S.; Guha, A.K.; Lee, Y.T.

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 shortcomingsmore » 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.« less

Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

NASA Technical Reports Server (NTRS)

Willis, Peter; Hunt, Brian; White,Victor; Grunthaner, Frank

2008-01-01

A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013. Fabrication processes have been developed to make the microfabricated Teflon-AF microfluidic diaphragm pumps capable of surviving extreme temperature excursions before and after exposure to liquid water. Two glass wafers are etched with features and a continuous Teflon membrane is sandwiched between them (see figure). Single valves are constructed using this geometry. The microfabricated devices are then post processed by heating the assembled device while applying pneumatic pressure to force the Teflon diaphragm against the valve seat while it is softened. After cooling the device, the embossed membrane retains this new shape. This solves previous problems with bubble introduction into the fluid flow where deformations of the membrane at the valve seat occurred during device bonding at elevated temperatures (100-150 C). The use of laminated membranes containing commercial Teflon AF 2400 sheet sandwiched between spun Teflon AF 1600 layers performed best, and were less gas permeable than Teflon AF 1600 membranes on their own. Spinning Teflon AF 1600 solution (6 percent in FLOURINERT(Registered TradeMark) FC40 solvent, 3M Company) at 500 rpm for 1.5 seconds, followed by 1,000 rpm for 3 seconds onto Borofloat glass wafers, results in a 10-micron-thick film of extremely smooth Teflon AF. This spinning process is repeated several times on flat, blank, glass wafers in order to gradually build a thick, smooth membrane. After running this process at least five times, the wafer and Teflon coating are heated under vacuum at 220 C for one hour in order to drive off any residual solvent present in the composite film. After this, a second blank, glass wafer is brought down from above and the stack is held under vacuum at 3 atm mechanical pressure for ten 10 hours.

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.

A Simple, Cost-Efficient Method to Separate Microalgal Lipids from Wet Biomass Using Surface Energy-Modified Membranes.

PubMed

Kwak, Moo Jin; Yoo, Youngmin; Lee, Han Sol; Kim, Jiyeon; Yang, Ji-Won; Han, Jong-In; Im, Sung Gap; Kwon, Jong-Hee

2016-01-13

For the efficient separation of lipid extracted from microalgae cells, a novel membrane was devised by introducing a functional polymer coating onto a membrane surface by means of an initiated chemical vapor deposition (iCVD) process. To this end, a steel-use-stainless (SUS) membrane was modified in a way that its surface energy was systemically modified. The surface modification by conformal coating of functional polymer film allowed for selective separation of oil-water mixture, by harnessing the tuned interfacial energy between each liquid phase and the membrane surface. The surface-modified membrane, when used with chloroform-based solvent, exhibited superb permeate flux, breakthrough pressure, and also separation yield: it allowed separation of 95.5 ± 1.2% of converted lipid (FAME) in the chloroform phase from the water/MeOH phase with microalgal debris. This result clearly supported that the membrane-based lipid separation is indeed facilitated by way of membrane being functionalized, enabling us to simplify the whole downstream process of microalgae-derived biodiesel production.

Mechanical properties and XRD of Nafion modified by 2-hydroxyethylammonium ionic liquids

NASA Astrophysics Data System (ADS)

Garaev, V.; Pavlovica, S.; Reinholds, I.; Vaivars, G.

2013-12-01

In this work, the Nafion 112 membrane impregnated with 2-hydroxyethylammonium carboxylate ionic liquids have been investigated. The used ionic liquids were 2-hydroxyethylammonium formate [HEA]F, acetate [HEA]A and lactate [HEA]L. Prepared composite membranes Nafion/ionic liquid are characterized by mechanical testing, such as tensile test and creep test. It is found that ionic liquids decrease elastic modulus and creep compliance, but do not have significant effect on the tensile strength. Also, composite membranes were studied by wide angle X-ray diffraction. All ionic liquids shift the peak maximum to the lower angle. In this work, only biodegradable ionic liquids were used for composite preparation.

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.

Immobilized fluid membranes for gas separation

DOEpatents

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.

Lysimeter apparatus

DOEpatents

Clark, Don T.; Erickson, Eugene E.; Casper, William L.; Everett, David M.; Hubbell, Joel M.; Sisson, James B.

2005-09-06

A suction lysimeter for sampling subsurface liquids includes a lysimeter casing having a drive portion, a reservoir portion, and a tip portion, the tip portion including a membrane through which subsurface liquids may be sampled; a fluid conduit coupled in fluid flowing relation relative to the membrane, and which in operation facilitates the delivery of the sampled subsurface liquids from the membrane to the reservoir portion; and a plurality of tubes coupled in fluid flowing relation relative to the reservoir portion, the tubes in operation facilitating delivery of the sampled subsurface liquids from the reservoir portion for testing. A method of sampling subsurface liquids comprises using this lysimeter.

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 well as fully explain up-to-date mechanisms and models of water transport and molecular separation behavior, which will arouse great interest among researchers entering or already working in the field of 2D material-based membranes.

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 well as fully explain up-to-date mechanisms and models of water transport and molecular separation behavior, which will arouse great interest among researchers entering or already working in the field of 2D material-based membranes.

Ultrathin-skinned asymmetric membranes by immiscible solvents treatment

DOEpatents

Friesen, Dwayne T.; Babcock, Walter C.

1989-01-01

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.

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.

Composites of ionic liquid and amine-modified SAPO 34 improve CO2 separation of CO2-selective polymer membranes

NASA Astrophysics Data System (ADS)

Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhang, Li; Zhou, Junhu; Cen, Kefa

2017-07-01

Mixed matrix membranes with ionic liquids and molecular sieve particles had high CO2 permeabilities, but CO2 separation from small gas molecules such as H2 was dissatisfied because of bad interfacial interaction between ionic liquid and molecular sieve particles. To solve that, amine groups were introduced to modify surface of molecular sieve particles before loading with ionic liquid. SAPO 34 was adopted as the original filler, and four mixed matrix membranes with different fillers were prepared on the outer surface of ceramic hollow fibers. Both surface voids and hard agglomerations disappeared, and the surface became smooth after SAPO 34 was modified by amine groups and ionic liquid [P66614][2-Op]. Mixed matrix membranes with composites of amine-modified SAPO 34 and ionic liquid exhibited excellent CO2 permeability (408.9 Barrers) and CO2/H2 selectivity (22.1).

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.

Method for forming a chemical microreactor

DOEpatents

Morse, Jeffrey D [Martinez, CA; Jankowski, Alan [Livermore, CA

2009-05-19

Disclosed is a chemical microreactor that provides a means to generate hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water. The microreactor contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. Two distinct embodiment styles are discussed. One embodiment style employs a packed catalyst capillary microchannel and at least one porous membrane. Another embodiment style employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2/cm.sup.3. Various methods to form packed catalyst capillary microchannels, porous membranes and porous membrane support structures are also disclosed.

The Rheological Properties of Lipid Monolayers Modulate the Incorporation of l-Ascorbic Acid Alkyl Esters.

PubMed

Díaz, Yenisleidy de Las Mercedes Zulueta; Mottola, Milagro; Vico, Raquel V; Wilke, Natalia; Fanani, María Laura

2016-01-19

In this work, we tested the hypothesis that the incorporation of amphiphilic drugs into lipid membranes may be regulated by their rheological properties. For this purpose, two members of the l-ascorbic acid alkyl esters family (ASCn) were selected, ASC16 and ASC14, which have different rheological properties when organized at the air/water interface. They are lipophilic forms of vitamin C used in topical pharmacological preparations. The effect of the phase state of the host lipid membranes on ASCn incorporation was explored using Langmuir monolayers. Films of pure lipids with known phase states have been selected, showing liquid-expanded, liquid-condensed, and solid phases as well as pure cholesterol films in liquid-ordered state. We also tested ternary and quaternary mixed films that mimic the properties of cholesterol containing membranes and of the stratum corneum. The compressibility and shear properties of those monolayers were assessed in order to define its phase character. We found that the length of the acyl chain of the ASCn compounds induces differential changes in the rheological properties of the host membrane and subtly regulates the kinetics and extent of the penetration process. The capacity for ASCn uptake was found to depend on the phase state of the host film. The increase in surface pressure resultant after amphiphile incorporation appears to be a function of the capacity of the host membrane to incorporate such amphiphile as well as the rheological response of the film. Hence, monolayers that show a solid phase state responded with a larger surface pressure increase to the incorporation of a comparable amount of amphiphile than liquid-expanded ones. The cholesterol-containing films, including the mixture that mimics stratum corneum, allowed a very scarce ASCn uptake independently of the membrane diffusional properties. This suggests an important contribution of Cho on the maintenance of the barrier function of stratum corneum.

The effect of residual cationic polymers in swine wastewater on the fouling of reverse osmosis membranes.

PubMed

Pedersen, C O; Masse, L; Hjorth, M

2014-01-01

Solid-liquid separation with flocculation can be used as pre-treatment for reverse osmosis (RO) filtration as it produces a liquid fraction (LF) low in suspended solids (SS). However, residual polymers in the LF may foul the membrane. Membrane fouling during RO filtration of swine wastewater containing polymers was investigated with respect to polymer charge density (CD), effluent SS concentration and membrane surface charge. Effluents with 765 mg/L SS and without SS were spiked with low and medium CD polymers (0-40 mg/L effluent) then processed with RO membranes having low and high negative surface charges. Fouling intensity was evaluated by comparing permeate flux and water flux recovery of fouled and cleaned membranes. For effluents containing SS, the presence of polymer reduced permeate flux by 4-16% and water flux recovery of the fouled membrane by 0-18%, relative to effluents without polymer. The extent of the fouling was higher with the low than the medium CD polymer. The fouling was mostly reversible as cleaning allowed for over 95% flux recovery, but the membrane with high negative surface charge was more susceptible to irreversible fouling. Adding the low CD polymer to feed without SS had no effect on permeate flux or flux recovery. Membrane fouling thus appeared to be caused by the polymer changing SS-membrane interaction. If flocculation is applied to pre-treat manure, a medium CD polymer should be used to optimize SS removal and a membrane with low surface charge should be selected to minimize fouling.

Polymeric water filtration membranes

NASA Astrophysics Data System (ADS)

Paul, Mou

Nanofiltration (NF) membranes are used for separating salts and small neutral molecules. NF membranes show unique selectivity properties compared to reverse osmosis membranes as it can selectively pass monovalent salts and neutral molecules as a function of charge and molecular weight cut-off which are dependent on membrane characteristics and operating conditions. Dow Water and Process solutions has been a pioneer in the membrane based water purification field and Dow's role was instrumental in developing several NF membranes for different applications. However, the characterization of NF membranes and hence the development of structure-property relationship is challenging due to the nanoscale thin, crosslinked nature of the membrane. Recently significant efforts were employed to develop analytical capabilities to understand polymer structure and composition and it had been possible to achieve a structure-property relationship for NF membranes. This paper will highlight similar relationships and will also focus on the relationships of membrane structure with membrane transport properties and how this relationship influences products for different application areas such as in oil field, sweetener and minimum liquid discharge etc.

Membranes for nanometer-scale mass fast transport

DOEpatents

Bakajin, Olgica [San Leandro, CA; Holt, Jason [Berkeley, CA; Noy, Aleksandr [Belmont, CA; Park, Hyung Gyu [Oakland, CA

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.

Microencapsulation and Electrostatic Processing Method

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

2000-01-01

Methods are provided for forming spherical multilamellar microcapsules having alternating hydrophilic and hydrophobic liquid layers, surrounded by flexible, semi-permeable hydrophobic or hydrophilic outer membranes which can be tailored specifically to control the diffusion rate. The methods of the invention rely on low shear mixing and liquid-liquid diffusion process and are particularly well suited for forming microcapsules containing both hydrophilic and hydrophobic drugs. These methods can be carried out in the absence of gravity and do not rely on density-driven phase separation, mechanical mixing or solvent evaporation phases. The methods include the process of forming, washing and filtering microcapsules. In addition, the methods contemplate coating microcapsules with ancillary coatings using an electrostatic field and free fluid electrophoresis of the microcapsules. The microcapsules produced by such methods are particularly useful in the delivery of pharmaceutical compositions.

Processing, Properties and Morphology of Optical Limiting Silk Membranes

DTIC Science & Technology

2006-02-28

Christopher Brewer, Donald Ott, Polymer, 45 8451 (2004). 2. Electrospun Bombyx mori Gland Silk, S. Putthanarat, R.K. Eby, W. Kataphinan, S. Jones, R...Science, The University of Akron, Akron, OH. 3. American Physical Society (APS) meeting, March 2005, "Electrospun liquid silk from the gland of Bombyx Mori ...provide a good compatible matrix. They have previously demonstrated that GFP molecules can be incorporated into cast membranes of silk from B. mori

Design of Microporosity in Membrane Distillation

NASA Astrophysics Data System (ADS)

Zhao, Tom; Patankar, Neelesh

2017-11-01

Membrane Distillation (MD) is a desalination method where only vapor can pass through pores in a hydrophobic membrane. Unlike reverse osmosis, MD is insensitive to feed salinity (osmotic pressure) and demonstrates near 100% salt rejection in processing wastewater with a high concentration of nonvolatile impurities. To maximize vapor flux and maintain salt rejection, we demonstrate using molecular dynamics the critical pore radius below which the liquid feed will not intrude or nucleate inside the pores for cylindrical, re-entrant and conical pore geometries. We note that re-entrant structures not only can process low surface-tension wastewater due to its inherent oleophobicity, but can also be optimized to achieve maximum vapor transport compared to all other pore geometries as a function of the material hydrophobicity.

Evaluation of two membrane-based microextraction techniques for the determination of endocrine disruptors in aqueous samples by HPLC with diode array detection.

PubMed

Luiz Oenning, Anderson; Lopes, Daniela; Neves Dias, Adriana; Merib, Josias; Carasek, Eduardo

2017-11-01

In this study, the viability of two membrane-based microextraction techniques for the determination of endocrine disruptors by high-performance liquid chromatography with diode array detection was evaluated: hollow fiber microporous membrane liquid-liquid extraction and hollow-fiber-supported dispersive liquid-liquid microextraction. The extraction efficiencies obtained for methylparaben, ethylparaben, bisphenol A, benzophenone, and 2-ethylhexyl-4-methoxycinnamate from aqueous matrices obtained using both approaches were compared and showed that hollow fiber microporous membrane liquid-liquid extraction exhibited higher extraction efficiency for most of the compounds studied. Therefore, a detailed optimization of the extraction procedure was carried out with this technique. The optimization of the extraction conditions and liquid desorption were performed by univariate analysis. The optimal conditions for the method were supported liquid membrane with 1-octanol for 10 s, sample pH 7, addition of 15% w/v of NaCl, extraction time of 30 min, and liquid desorption in 150 μL of acetonitrile/methanol (50:50 v/v) for 5 min. The linear correlation coefficients were higher than 0.9936. The limits of detection were 0.5-4.6 μg/L and the limits of quantification were 2-16 μg/L. The analyte relative recoveries were 67-116%, and the relative standard deviations were less than 15.5%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficient gas-liquid contact using microfluidic membrane devices with staggered herringbone mixers.

PubMed

Femmer, Tim; Eggersdorfer, Max L; Kuehne, Alexander J C; Wessling, Matthias

2015-08-07

We describe a novel membrane based gas-liquid-contacting device with increased mass transport and reduced pressure loss by combining a membrane with a staggered herringbone static mixer. Herringbone structures are imposed on the microfluidic channel geometry via soft lithography, acting as mixers which introduce secondary flows at the membrane interface. Such flows include Dean vortices and Taylor flows generating effective mixing while improving mass transport and preventing concentration polarization in microfluidic channels. Furthermore, our static herringbone mixer membranes effectively reduce pressure losses leading to devices with enhanced transfer properties for microfluidic gas-liquid contact. We investigate the red blood cell distribution to tailor our devices towards miniaturised extracorporeal membrane oxygenation and improved comfort of patients with lung insufficiencies.

How Lipid Membranes Affect Pore Forming Toxin Activity.

PubMed

Rojko, Nejc; Anderluh, Gregor

2015-12-15

Pore forming toxins (PFTs) evolved to permeate the plasma membrane of target cells. This is achieved in a multistep mechanism that usually involves binding of soluble protein monomer to the lipid membrane, oligomerization at the plane of the membrane, and insertion of part of the polypeptide chain across the lipid membrane to form a conductive channel. Introduced pores allow uncontrolled transport of solutes across the membrane, inflicting damage to the target cell. PFTs are usually studied from the perspective of structure-function relationships, often neglecting the important role of the bulk membrane properties on the PFT mechanism of action. In this Account, we discuss how membrane lateral heterogeneity, thickness, and fluidity influence the pore forming process of PFTs. In general, lipid molecules are more accessible for binding in fluid membranes due to steric reasons. When PFT specifically binds ordered domains, it usually recognizes a specific lipid distribution pattern, like sphingomyelin (SM) clusters or SM/cholesterol complexes, and not individual lipid species. Lipid domains were also suggested to act as an additional concentration platform facilitating PFT oligomerization, but this is yet to be shown. The last stage in PFT action is the insertion of the transmembrane segment across the membranes to build the transmembrane pore walls. Conformational changes are a spontaneous process, and sufficient free energy has to be available for efficient membrane penetration. Therefore, fluid bilayers are permeabilized more readily in comparison to highly ordered and thicker liquid ordered lipid phase (Lo). Energetically more costly insertion into the Lo phase can be driven by the hydrophobic mismatch between the thinner liquid disordered phase (Ld) and large protein complexes, which are unable to tilt like single transmembrane segments. In the case of proteolipid pores, membrane properties can directly modulate pore size, stability, and even selectivity. Finally, events associated with pore formation can modulate properties of the lipid membrane and affect its organization. Model membranes do not necessarily reproduce the physicochemical properties of the native cellular membrane, and caution is needed when transferring results from model to native lipid membranes. In this context, the utilization of novel approaches that enable studying PFTs on living cells at a single molecule level should reveal complex protein-lipid membrane interactions in greater detail.

Microgravity and Charge Transfer in the Neuronal Membrane: Implications for Computational Neurobiology

NASA Technical Reports Server (NTRS)

Wallace, Ron

1995-01-01

Evidence from natural and artificial membranes indicates that the neural membrane is a liquid crystal. A liquid-to-gel phase transition caused by the application of superposed electromagnetic fields to the outer membrane surface releases spin-correlated electron pairs which propagate through a charge transfer complex. The propagation generates Rydberg atoms in the lipid bilayer lattice. In the present model, charge density configurations in promoted orbitals interact as cellular automata and perform computations in Hilbert space. Due to the small binding energies of promoted orbitals, their automata are highly sensitive to microgravitational perturbations. It is proposed that spacetime is classical on the Rydberg scale, but formed of contiguous moving segments, each of which displays topological equivalence. This stochasticity is reflected in randomized Riemannian tensor values. Spacetime segments interact with charge automata as components of a computational process. At the termination of the algorithm, an orbital of high probability density is embedded in a more stabilized microscopic spacetime. This state permits the opening of an ion channel and the conversion of a quantum algorithm into a macroscopic frequency code.

Lysimeter methods and apparatus

DOEpatents

Clark, Don T.; Erickson, Eugene E.; Casper, William L.; Everett, David M.; Hubbell, Joel M.; Sisson, James B.

2004-12-07

A suction lysimeter for sampling subsurface liquids includes a lysimeter casing having a drive portion, a reservoir portion, and a tip portion, the tip portion including a membrane through which subsurface liquids may be sampled; a fluid conduit coupled in fluid flowing relation relative to the membrane, and which in operation facilitates the delivery of the sampled subsurface liquids from the membrane to the reservoir portion; and a plurality of tubes coupled in fluid flowing relation relative to the reservoir portion, the tubes in operation facilitating delivery of the sampled subsurface liquids from the reservoir portion for testing. A method of sampling subsurface liquids comprises using this lysimeter.

Tuning the self-assembled 1,3:2,4-di(3,4-dimethylbenzylidene) sorbitol nanoarchitectures using the phase inversion method

NASA Astrophysics Data System (ADS)

Lai, Wei-Chi; Tseng, Shen-Jhen

2013-11-01

1,3:2,4-Di(3,4-dimethylbenzylidene) sorbitol (DMDBS) molecules can self-assemble into nanoscaled structures in organic solvents and polymer melts. The nanofibril structures were the mostly found. In this study, we used two phase inversion methods, i.e., dry and wet methods, to obtain different DMDBS nanoarchitectures. Poly(vinylidene fluoride) (PVDF) was chosen as polymer matrix, and the DMDBS structures were tuned by the process of PVDF membrane formation (crystallization and liquid-liquid demixing). When the membrane was prepared using the dry method, the DMDBS structure is controlled by the PVDF crystallization. Fewer DMDBS nanofibrils formed on the surfaces, and no nanofibrils were found in the cross-sections. On the other hand, when the membrane was prepared using the wet method, the liquid-liquid demixing (nonsolvent induced phase separation) occurred simultaneously as PVDF crystallized, and thus influenced the aggregation of DMDBS molecules. DMDBS is an amphiphilic molecule with two hydrophilic hydroxyl groups. The addition of nonsolvent (water) caused a large number of DMDBS molecules to aggregate outside the hydrophobic PVDF. In addition, a new structure "nanomat" was found. The mat was composed of DMDBS nanofibrils with diameters of 10-20 nm, similar to those observed in the dry method membranes. Fourier transform infra-red spectroscopy indicates that the DMDBS molecules self-assembled (aggregated) mainly through intermolecular hydrogen bonding in the presence of PVDF. The more intermolecular hydrogen bonding between DMDBS existed, the more excessive amounts of DMDBS molecules were, leading to the formation of nanomats.

Coupling fiber optics to a permeation liquid membrane for heavy metal sensor development.

PubMed

Ueberfeld, Jörn; Parthasarathy, Nalini; Zbinden, Hugo; Gisin, Nicolas; Buffle, Jacques

2002-02-01

We present the first sensing system for metal ions based on the combination of separation/preconcentration by a permeation liquid membrane (PLM) and fluorescence detection with an optical fiber. As a model, a system for the detection of Cu(II) ions was developed. The wall of a polypropylene hollow fiber serves as support for the permeable liquid membrane. The lumen of the fiber contains the strip solution in which Cu(II) is accumulated. Calcein, a fluorochromic dye, acts as stripping agent and at the same time as metal indicator. The quenching of the calcein fluorescence upon metal accumulation in the strip phase is detected with a multimode optical fiber, which is incorporated into the lumen. Fluorescence is excited with a blue LED and detected with a photon counter. Taking advantage of the high selectivity and sensitivity of PLM preconcentration, a detection limit for Cu(II) of approximately 50 nM was achieved. Among five tested heavy metal ions, Pb(II) was the only major interfering species. The incorporation of small silica optical fibers into the polypropylene capillary allows for real-time monitoring of the Cu(II) accumulation process.

Sensors and filters based on nano- and microchannel membranes for biomedical technologies

NASA Astrophysics Data System (ADS)

Romanov, S. I.; Pyshnyi, D. V.; Laktionov, P. P.

2012-02-01

A new technology is presented in a concise form which enables the silicon membranes to be produced over a wide range of channel dimensions from a few nanometers to tens of micrometers. There is good reason to believe that this method based on rather simple technical processing is competitive with other technologies for fabricating nanofluidic analysis systems. Some of the completed developments involving microchannel membranes, namely, the optical DNA-sensor and the human cell separation system are demonstrated without going into details. The other applications of micro- and nanochannel membranes, namely, the electrical sensor and electrokinetic filters for detecting and separating liquids and biomolecules are shown with the first results and are in progress.

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.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

PubMed

Hermannsdörfer, Justus; de Jonge, Niels

2017-02-05

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

PubMed Central

Hermannsdörfer, Justus; de Jonge, Niels

2017-01-01

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline. PMID:28190028

Supported liquid inorganic membranes for nuclear waste separation

DOEpatents

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

2015-04-07

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasaribu, Marvin H., E-mail: marvin-shady88@yahoo.com; Arcana, I Made, E-mail: arcana@chem.itb.ac.id; Wahyuningrum, Deana, E-mail: deana@chem.itb.ac.id

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 anionmore » 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)« less

Hypophosphites as eco-compatible fuel for membrane-free direct liquid fuel cells.

PubMed

Wang, Renhe; Wu, Mengjia; Haller, Servane; Métivier, Pascal; Wang, Yonggang; Xia, Yongyao

2018-05-07

Crossover of liquid fuel remains a severe problem for conventional direct liquid fuel cells even when polymer electrolyte membranes are applied. Herein, we report for the first time a membrane-free direct liquid fuel cell powered by alkaline hypophosphite solution. The proof-of-concept fuel cell yields a peak power density of 32 mW cm-2 under air flow at room temperature. The removal of the polymer electrolyte membrane is attributed to the high reactivity and selectivity of Pd and α-MnO2 towards the hypophosphite oxidation on anode and oxygen reduction on the cathode, respectively. The discharge products are analyzed by 31P-NMR and the Faradaic efficiencies have been calculated after discharging at 10 mA cm-2 for 20 hours. The non-toxicity of hypophosphite and membrane-free fuel cell structure provide huge potential for future applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon dioxide removal process

DOEpatents

Baker, Richard W.; Da Costa, Andre R.; Lokhandwala, Kaaeid A.

2003-11-18

A process and apparatus for separating carbon dioxide from gas, especially natural gas, that also contains C.sub.3+ hydrocarbons. The invention uses two or three membrane separation steps, optionally in conjunction with cooling/condensation under pressure, to yield a lighter, sweeter product natural gas stream, and/or a carbon dioxide stream of reinjection quality and/or a natural gas liquids (NGL) stream.

Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part II. In operando synchrotron imaging for microscale liquid water transport characterization

NASA Astrophysics Data System (ADS)

Chevalier, S.; Ge, N.; Lee, J.; George, M. G.; Liu, H.; Shrestha, P.; Muirhead, D.; Lavielle, N.; Hatton, B. D.; Bazylak, A.

2017-06-01

This is the second paper in a two-part series in which we investigate the impact of the gas diffusion layer structure on the liquid water distribution in an operating polymer electrolyte membrane (PEM) fuel cell through the procedures of design, fabrication, and testing of novel hydrophobic electrospun gas diffusion layers (eGDLs). In this work, fibre diameters and alignment in eGDLs are precisely controlled, and concurrent synchrotron X-ray radiography and electrochemical impedance spectroscopy (EIS) are used to evaluate the influence of the controlled eGDL parameters on the liquid water distribution and on membrane liquid water content. For eGDLs with small fibre diameters (150-200 nm) and correspondingly smaller pore sizes, reduced liquid water accumulation under the flow field ribs is observed. However, more liquid water is pinned onto the eGDL - at the interface with flow field channels. Orienting fibre alignment perpendicular to the flow field channel direction leads to improved eGDL-catalyst layer contact and prevents rib-channel membrane deformation. On the other hand, eGDLs facilitate significant membrane dry-out, even under highly humidified operating conditions at high current densities.

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.

Magnetically Enhanced Solid-Liquid Separation

NASA Astrophysics Data System (ADS)

Rey, C. M.; Keller, K.; Fuchs, B.

2005-07-01

DuPont is developing an entirely new method of solid-liquid filtration involving the use of magnetic fields and magnetic field gradients. The new hybrid process, entitled Magnetically Enhanced Solid-Liquid Separation (MESLS), is designed to improve the de-watering kinetics and reduce the residual moisture content of solid particulates mechanically separated from liquid slurries. Gravitation, pressure, temperature, centrifugation, and fluid dynamics have dictated traditional solid-liquid separation for the past 50 years. The introduction of an external field (i.e. the magnetic field) offers the promise to manipulate particle behavior in an entirely new manner, which leads to increased process efficiency. Traditional solid-liquid separation typically consists of two primary steps. The first is a mechanical step in which the solid particulate is separated from the liquid using e.g. gas pressure through a filter membrane, centrifugation, etc. The second step is a thermal drying process, which is required due to imperfect mechanical separation. The thermal drying process is over 100-200 times less energy efficient than the mechanical step. Since enormous volumes of materials are processed each year, more efficient mechanical solid-liquid separations can be leveraged into dramatic reductions in overall energy consumption by reducing downstream drying requirements have a tremendous impact on energy consumption. Using DuPont's MESLS process, initial test results showed four very important effects of the magnetic field on the solid-liquid filtration process: 1) reduction of the time to reach gas breakthrough, 2) less loss of solid into the filtrate, 3) reduction of the (solids) residual moisture content, and 4) acceleration of the de-watering kinetics. These test results and their potential impact on future commercial solid-liquid filtration is discussed. New applications can be found in mining, chemical and bioprocesses.

Integration between chemical oxidation and membrane thermophilic biological process.

PubMed

Bertanza, G; Collivignarelli, M C; Crotti, B M; Pedrazzani, R

2010-01-01

Full scale applications of activated sludge thermophilic aerobic process for treatment of liquid wastes are rare. This experimental work was carried out at a facility, where a thermophilic reactor (1,000 m(3) volume) is operated. In order to improve the global performance of the plant, it was decided to upgrade it, by means of two membrane filtration units (ultrafiltration -UF-, in place of the final sedimentation, and nanofiltration -NF-). Subsequently, the integration with chemical oxidation (O(3) and H(2)O(2)/UV processes) was taken into consideration. Studied solutions dealt with oxidation of both the NF effluents (permeate and concentrate). Based on experimental results and economic evaluation, an algorithm was proposed for defining limits of convenience of this process.

Quantifying the Relationship between Curvature and Electric Potential in Lipid Bilayers.

PubMed

Bruhn, Dennis S; Lomholt, Michael A; Khandelia, Himanshu

2016-06-02

Cellular membranes mediate vital cellular processes by being subject to curvature and transmembrane electrical potentials. Here we build upon the existing theory for flexoelectricity in liquid crystals to quantify the coupling between lipid bilayer curvature and membrane potentials. Using molecular dynamics simulations, we show that headgroup dipole moments, the lateral pressure profile across the bilayer, and spontaneous curvature all systematically change with increasing membrane potentials. In particular, there is a linear dependence between the bending moment (the product of bending rigidity and spontaneous curvature) and the applied membrane potentials. We show that biologically relevant membrane potentials can induce biologically relevant curvatures corresponding to radii of around 500 nm. The implications of flexoelectricity in lipid bilayers are thus likely to be of considerable consequence both in biology and in model lipid bilayer systems.

Numerical and experimental study of actuator performance on piezoelectric microelectromechanical inkjet print head.

PubMed

Van So, Pham; Jun, Hyun Woo; Lee, Jaichan

2013-12-01

We have investigated the actuator performance of a piezoelectrically actuated inkjet print head via the numerical and experimental analysis. The actuator consisting of multi-layer membranes, such as piezoelectric, elastic and other buffer layers, and ink chamber was fabricated by MEMS processing. The maximum displacement of the actuator membrane obtained in the experiment is explained by numerical analysis. A simulation of the actuator performance with fluidic damping shows that the resonant frequency of the membrane in liquid is reduced from its resonant frequency in air by a factor of three, which was also verified in the experiment. These simulation and experimental studies demonstrate how much "dynamic force," in terms of a membrane's maximum displacement, maximum force and driving frequency, can be produced by an actuator membrane interacting with fluid.

The analysis of the wavefront aberration caused by the gravity of the tunable-focus liquid-filled membrane lens

NASA Astrophysics Data System (ADS)

Zhang, Wei; Liu, Pengfei; Wei, Xiaona; Zhuang, Songlin; Yang, Bo

2010-11-01

Liquid lens is a novel optical device which can implement active zooming. With liquid lens, zoom camera can be designed with more miniature size and simpler structure than before. It is thought that the micro zoom system with liquid lens has a very wide potential applications in many fields, in which the volume and weight of the system are critically limited, such as endoscope, mobile, PDA and so on. There are mainly three types of tunable-focus liquid lens: liquid crystal lens, electrowetting effect based liquid lens and liquid-filled membrane lens. Comparing with the other two kinds of liquid lens, the liquid-filled membrane lens has the advantages of simple structure, flexible aperture and high zooming efficiency. But its membrane surface will have an initial shape deformation caused by the gravity when the aperture of the lens is at large size, which will lead to the wave front aberration and the imaging quality impairing. In this paper, the initial deformation of the lens caused by the gravity was simulated based on the theory of Elastic Mechanics, which was calculated by the Finite Element Analysis method. The relationship between the diameter of the lens and the wave front aberration caused by the gravity was studied. And the Optical path difference produced by different liquid density was also analyzed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holt, Allison M; Standaert, Robert F; Jubb, Aaron M

Biological membranes, formed primarily by the self-assembly of complex mixtures of phospholipids, provide a structured scaffold for compartmentalization and structural processes in living cells. The specific physical properties of phospholipid species present in a given membrane play a key role in mediating these processes. Phosphatidylethanolamine (PE), a zwitterionic lipid present in bacterial, yeast, and mammalian cell membranes, is exceptional. In addition to undergoing the standard lipid polymorphic transition between the gel and liquid-crystalline phase, it can also assume an unusual polymorphic state, the inverse hexagonal phase (HII). Divalent cations are among the factors that drive the formation of the HIImore » phase, wherein the lipid molecules form stacked tubular structures by burying the hydrophilic head groups and exposing the hydrophobic tails to the bulk solvent. Most biological membranes contain a lipid species capable of forming the HII state suggesting that such lipid polymorphic structural states play an important role in structural biological processes such as membrane fusion. In this study, the interactions between Mg2+ and biomimetic bacterial cell membranes composed of PE and phosphatidylglycerol (PG) were probed using differential scanning calorimetry (DSC), small-angle x-ray scattering (SAXS), and fluorescence spectroscopy. The lipid phase transitions were examined at varying ratios of PE to PG and upon exposure to physiologically relevant concentrations of Mg2+. An understanding of these basic interactions enhances our understanding of membrane dynamics and how membrane-mediated structural changes may occur in vivo.« less

Selective removal of cesium by ammonium molybdophosphate - polyacrylonitrile bead and membrane.

PubMed

Ding, Dahu; Zhang, Zhenya; Chen, Rongzhi; Cai, Tianming

2017-02-15

The selective removal of radionuclides with extremely low concentrations from environmental medium remains a big challenge. Ammonium molybdophosphate possess considerable selectivity towards cesium ion (Cs + ) due to the specific ion exchange between Cs + and NH 4 + . Ammonium molybdophosphate - polyacrylonitrile (AMP-PAN) membrane was successfully prepared for the first time in this study. Efficient removal of Cs + (95.7%, 94.1% and 91.3% of 1mgL -1 ) from solutions with high ionic strength (400mgL -1 of Na + , Ca 2+ or K + ) was achieved by AMP-PAN composite. Multilayer chemical adsorption process was testified through kinetic and isotherm studies. The estimated maximum adsorption capacities even reached 138.9±21.3mgg -1 . Specifically, the liquid film diffusion was identified as the rate-limiting step throughout the removal process. Finally, AMP-PAN membrane could eliminate Cs + from water effectively through the filtration adsorption process. Copyright © 2016 Elsevier B.V. All rights reserved.

Tunable-focus liquid lens controlled using a servo motor

NASA Astrophysics Data System (ADS)

Ren, Hongwen; Fox, David; Anderson, P. Andrew; Wu, Benjamin; Wu, Shin-Tson

2006-09-01

We demonstrated a liquid lens whose focal length can be controlled by an actuator. The lens cell is composed of elastic membrane, planar glass plate, a periphery sealing ring, and a liquid with a fixed volume in the lens chamber. Part of the periphery sealing ring is excavated to form a hollow chamber which functions as a reservoir. This hollowed periphery is surrounded by an exterior rubber membrane. The shaft of an actuator is used to deform the elastic rubber. Squeezing the liquid contained in the reservoir into the lens chamber. Excess liquid in the lens chamber will push the lens membrane to outward, resulting in a lens shape change. Due to the compact structure and easy operation, this liquid lens has potential applications in zoom lenses, auto beam steering, and eyeglasses.

Method development for the analysis of ionophore antimicrobials in dairy manure to assess removal within a membrane-based treatment system.

PubMed

Hurst, Jerod J; Wallace, Josh S; Aga, Diana S

2018-04-01

Ionophore antimicrobials are heavily used in the livestock industries, both for preventing animal infection by coccidia protozoa and for increasing feed efficiency. Ionophores are excreted mostly unmetabolized and are released into the environment when manure is land-applied to fertilize croplands. Here, an analytical method was optimized to study the occurrences of five ionophore residues (monensin, lasalocid, maduramycin, salinomycin, and narasin) in dairy manure after solid-liquid separation and further treatment of the liquid manure by a membrane-based treatment system. Ionophore residues from the separated solid manure (dewatered manure) and suspended solids of manure slurry samples were extracted using ultrasonication with methanol, followed by sample clean-up using solid phase extraction (SPE) and subsequent analysis via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The use of an ethyl acetate and methanol (1:1 v:v) mixture as an SPE eluent resulted in higher recoveries and lower method quantitation limits (MQL), when compared to using methanol. Overall recoveries from separated solid manure ranged from 73 to 134%. Liquid manure fractions were diluted with Nanopure™ water and cleaned up using SPE, where recoveries ranged from 51 to 100%. The developed extraction and LC-MS/MS methods were applied to analyze dairy manure samples subjected to an advanced manure treatment process involving a membrane-based filtration step (reverse osmosis). Monensin and lasalocid were detected at higher concentrations in the suspended solid fractions (4.40-420 ng/g for lasalocid and 85-1950 ng/g for monensin) compared to the liquid fractions (

Membrane protein stoichiometry studied in intact mammalian cells using liquid-phase electron microscopy.

PubMed

DE Jonge, N

2018-02-01

Receptor membrane proteins in the plasma membranes of cells respond to extracellular chemical signals by conformational changes, spatial redistribution, and (re-)assembly into protein complexes, for example, into homodimers (pairs of the same protein type). The functional state of the proteins can be determined from information about how subunits are assembled into protein complexes. Stoichiometric information about the protein complex subunits, however, is generally not obtained from intact cells but from pooled material extracted from many cells, resulting in a lack of fundamental knowledge about the functioning of membrane proteins. First, functional states may dramatically differ from cell to cell on account of cell heterogeneity. Second, extracting the membrane proteins from the plasma membrane may lead to many artefacts. Liquid-phase scanning transmission electron microscopy (STEM), in short liquid STEM, is a new technique capable of determining the locations of individual membrane proteins within the intact plasma membranes of cells in liquid. Many tens of whole cells can readily be imaged. It is possible to analyse the stoichiometry of membrane proteins in single cells while accounting for heterogenic cell populations. Liquid STEM was used to image epidermal growth factor receptors in whole COS7 cells. A study of the dimerisation of the HER2 protein in breast cancer cells revealed the presence of rare cancer cells in which HER2 was in a different functional state than in the bulk cells. Stoichiometric information about receptors is essential not only for basic science but also for biomedical application because they present many important pharmaceutical targets. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle.

PubMed

Đorđević, Jelena; Vladisavljević, Goran T; Trtić-Petrović, Tatjana

2017-01-01

A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P ≥ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

[Pollution prevention and control of aqueous extract of astragali radix processed with ZrO2 inorganic ceramic membrane micro-filtration].

PubMed

Pan, Lin-Men; Huang, Min-Yan; Guo, Li-Wei

2012-11-01

To study the measures for preventing and controlling the pollution of aqueous extract of Astragali Radix proceeded with inorganic ceramic membrane micro-filtration, in order to find effective measures for preventing and controlling the membrane pollution. The resistance distribution, polymer removal and changes in physical and chemical parameters of the zirconium oxide film of different pore diameters were determined to analyze the state or location of pollutants as well as the regularity of formation. Meanwhile, recoil and ultrasonic physical measures were adopted to strengthen the membrane process, in order to explore the methods for preventing and controlling the membrane pollution. When 0.2 microm of ZrO2 micro-filtrated aqueous extract of Astragali Radix, the rate of pollution was as high as 44.9%. The hole blocking resistance and the concentration polarization resistance were the main filtration resistances, while the surface deposit resistance decreased with the increase in the membrane's hold diameter; after micro-filtration, the liquid turbidity significantly reduced, with slight changes in both pH and viscosity. The 0.2 microm ZrO2 micro-filtration membrane performed better than the 0.05 microm pore size membrane in terms of conductivity. The 0. 2 microm and 0.05 microm pore diameter membranes showed better performance in the removal of pectin. The ultrasonic measure to strengthen membranes is more suitable to this system, with a flux rate up by 41.7%. The membrane optimization process adopts appropriate measures for preventing and controlling the membrane pollution, in order to reduce the membrane pollution, recover membrane performance and increase filtration efficiency.

Nanofiltration Membranes for Water Purification: structure-transport relationships and applications

NASA Astrophysics Data System (ADS)

Jons, Steven; Paul, Mou; Matthews, Tamlin; Hailemariam, Leaelaf

Nanofiltration (NF) membranes are used for separating salts and small neutral molecules. NF membranes show unique selectivity properties compared to reverse osmosis membranes as it can selectively pass monovalent salts and neutral molecules as a function of charge and molecular weight cut-off which are dependent on membrane characteristics and operating conditions. Dow Water & Process solutions has been a pioneer in the membrane based water purification field and Dow's role was instrumental in developing several NF membranes for different applications. However, the characterization of NF membranes and hence the development of structure-property relationship is challenging due to the nanoscale thin, crosslinked nature of the membrane. Recently significant efforts were employed to develop analytical capabilities to understand polymer structure and composition and it had been possible to achieve a structure-property relationship for NF membranes. This paper will highlight similar relationships and will also focus on the relationships of membrane structure with membrane transport properties and how this relationship influences products for different application areas such as in oil field, sweetener and minimum liquid discharge etc.

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

PubMed

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

2017-01-11

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

Electrospun Nanofiber-Coated Membrane Separators for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Lee, Hun

Lithium-ion batteries are widely used as a power source for portable electronic devices and hybrid electric vehicles due to their excellent energy and power densities, long cycle life, and enhanced safety. A separator is considered to be the critical component in lithium-ion rechargeable batteries. The separator is placed between the positive and negative electrodes in order to prevent the physical contact of electrodes while allowing the transportation of ions. In most commercial lithium-ion batteries, polyolefin microporous membranes are commonly used as the separator due to their good chemical stability and high mechanical strength. However, some of their intrinsic natures, such as low electrolyte uptake, poor adhesion property to the electrodes, and low ionic conductivity, can still be improved to achieve higher performance of lithium-ion batteries. In order to improve these intrinsic properties, polyolefin microporous membranes can be coated with nanofibers by using electrospinning technique. Electrospinning is a simple and efficient method to prepare nanofibers which can absorb a significant amount of liquid electrolyte to achieve low internal resistance and battery performance. This research presents the preparation and investigation of composite membrane separators prepared by coating nanofibers onto polyolefin microporous membranes via electrospinning technique. Polyvinylidene fluoride polymers and copolymers were used for the preparation of electrospun nanofiber coatings because they have excellent electrochemical stability, good adhesion property, and high temperature resistance. The nanofiber coatings prepared by electrospinning form an interconnected and randomly orientated structure on the surface of the polyolefin microporous membranes. The size of the nanofibers is on a scale that does not interfere with the micropores in the membrane substrates. The resultant nanofiber-coated membranes have the potential to combine advantages of both the polyolefin separator membranes and the nanoscale fibrous polymer coatings. The polyolefin microporous membranes serve as the supporting substrate which provides the required mechanical strength for the assembling process of lithium-ion batteries. The electrospun nanofiber coatings improve the wettability of the composite membrane separators to the liquid electrolyte, which is desirable for the lithium-ion batteries with high kinetics and good cycling performance. The results show that the nanofiber-coated membranes have enhanced adhesion properties to the battery electrode which can help prevent the formation of undesirable gaps between the separators and electrodes during prolonged charge-discharge cycles, especially in large-format batteries. The improvement on adhesive properties of nanofiber-coated membranes was evaluated by peel test. Nanofiber coatings applied to polyolefin membrane substrates improve the adhesion of separator membranes to battery electrodes. Electrolyte uptakes, ionic conductivities and interfacial resistances of the nanofiber-coated membrane separators were studied by soaking the membrane separators with a liquid electrolyte solution of 1 M lithium hexafluorophosphate dissolved in ethylene carbonate/dimethylcarbonate/ethylmethyl carbonate (1:1:1 vol). The nanofiber coatings on the surface of the membrane substrates increase the electrolyte uptake capacity due to the high surface area and capillary effect of nanofibers. The nanofiber-coated membranes soaked in the liquid electrolyte solution exhibit high ionic conductivities and low interfacial resistances to the lithium electrode. The cells containing LiFePO 4 cathode and the nanofiber-coated membranes as the separator show high discharge specific capacities and good cycling stability at room temperature. The nanofiber coatings on the membrane substrates contribute to high ionic conductivity and good electrochemical performance in lithium-ion batteries. Therefore, these nanofiber-coated composite membranes can be directly used as novel battery separators for high performance of lithium-ion batteries. Coating polyolefin microporous membranes with electrospun nanofibers is a promising approach to obtain highperformance separators for advanced lithium-ion batteries.

Superoleophobic yet Superhydrophilic surfaces for Continuous Liquid-Liquid Separation

DTIC Science & Technology

2011-12-08

cases, such membranes are oleophilic, i.e., Young’s contact angle (12) with oil !oil < 90º. Hydrophobic (or superhydrophobic (10, 11, 13)) and...continuous liquid-liquid separation. Final Report, Anish Tuteja, University of Michigan 3 hydrophobic (or superhydrophobic ) membranes are easily...in air typically loses its oleophobicity under water and vice-versa (17, 18). Despite numerous natural superhydrophobic surfaces (19, 20), due to

Liquid water breakthrough location distances on a gas diffusion layer of polymer electrolyte membrane fuel cells

NASA Astrophysics Data System (ADS)

Yu, Junliang; Froning, Dieter; Reimer, Uwe; Lehnert, Werner

2018-06-01

The lattice Boltzmann method is adopted to simulate the three dimensional dynamic process of liquid water breaking through the gas diffusion layer (GDL) in the polymer electrolyte membrane fuel cell. 22 micro-structures of Toray GDL are built based on a stochastic geometry model. It is found that more than one breakthrough locations are formed randomly on the GDL surface. Breakthrough location distance (BLD) are analyzed statistically in two ways. The distribution is evaluated statistically by the Lilliefors test. It is concluded that the BLD can be described by the normal distribution with certain statistic characteristics. Information of the shortest neighbor breakthrough location distance can be the input modeling setups on the cell-scale simulations in the field of fuel cell simulation.

QCM-D on mica for parallel QCM-D-AFM studies.

PubMed

Richter, Ralf P; Brisson, Alain

2004-05-25

Quartz crystal microbalance with dissipation monitoring (QCM-D) has developed into a recognized method to study adsorption processes in liquid, such as the formation of supported lipid bilayers and protein adsorption. However, the large intrinsic roughness of currently used gold-coated or silica-coated QCM-D sensors limits parallel structural characterization by atomic force microscopy (AFM). We present a method for coating QCM-D sensors with thin mica sheets operating in liquid with high stability and sensitivity. We define criteria to objectively assess the reliability of the QCM-D measurements and demonstrate that the mica-coated sensors can be used to follow the formation of supported lipid membranes and subsequent protein adsorption. This method allows combining QCM-D and AFM investigations on identical supports, providing detailed physicochemical and structural characterization of model membranes.

A two-step approach for copper and nickel extracting and recovering by emulsion liquid membrane.

PubMed

Bi, Qiang; Xue, Juanqin; Guo, Yingjuan; Li, Guoping; Cui, Haibin

2016-11-01

The recycling of copper and nickel from metallurgical wastewater using emulsion liquid membrane (ELM) was studied. P507 (2-ethylhexyl phosphonic acid-2-ethylhexyl ester) and TBP (tributyl phosphate) were used as carriers for the extraction of copper and nickel by ELMs, respectively. The influence of four emulsion composition variables, namely, the internal phase volume fraction (ϕ), surfactant concentration (Wsurf), internal phase stripping acid concentration (Cio) and the carrier concentration (Cc), and the process variable treat ratio on the extraction efficiencies of copper or nickel were studied. Under the optimum conditions, 98% copper and nickel were recycled by using ELM. The results indicated that ELM extraction is a promising industrial application technology to retrieve valuable metals in low concentration metallurgical wastewater.

Characterization of a supported ionic liquid membrane used for the removal of cyanide from wastewater.

PubMed

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

2017-12-01

This work evaluated the performance of ionic liquids (ILs) in supported liquid membranes in the removal of total cyanide from wastewater. Membranes were characterized by scanning electron microscopy and contact angle measurements to study the membrane morphology and wetting ability. In particular, the effects of operational parameters such as membrane immersion time, feed-phase concentration, and pH on cyanide removal were investigated. ILs are organic salts that are entirely composed of organic cations and either organic or inorganic anions. Since their vapor pressure is negligible, they can be handled easily; this characteristic gives rise to their 'green' nature. In this study, a hydrophobic IL, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF 6 ), was immobilized in the pores of a solid polymeric support made of polyvinylidene fluoride. The optimal conditions were as follows: 1 hour membrane immersion time, 312.24 mg/L feed-phase concentration, a feed-phase pH of 4, 3% NaOH solution, and 1 hour stirring time. The cyanide removal was 95.31%. The treatment of cyanide using supported ionic liquid membrane (SILM) technology is a method with potential applications in industry.

Surface modification of poly(vinylidene fluoride) hollow fibre membranes for biogas purification in a gas-liquid membrane contactor system.

PubMed

Jin, Pengrui; Huang, Chuan; Li, Jiaxiang; Shen, Yadong; Wang, Liao

2017-11-01

The wetting of hollow fibre membranes decreases the performance of the liquid-gas membrane contactor for CO 2 capture in biogas upgrading. To solve this problem, in this work, a poly(vinylidene fluoride) (PVDF) hollow fibre membrane for a liquid-gas membrane contactor was coated with a superhydrophobic layer composed of a combination of hydrophobic SiO 2 nanoparticles and polydimethylsiloxane (PDMS) by the method of spray deposition. A rough layer of SiO 2 deposited on the PVDF membrane resulted in an enhanced surface hydrophobicity. The surface structure of the pristine PVDF significantly affected the homogeneity of the generated SiO 2 layer. A uniform surface coating on the PVDF upper layer resulted from the presence of micrometre and nanometre-sized roughness on the surface of the PVDF membrane, which was achieved with a SiO 2 concentration of 4.44 mg ml -1 (0.2 g/45 ml) in the coating solution. As a result, the water contact angle of the modified surface was recorded as 155 ± 3°, which is higher than that of the pristine surface. The high contact angle is advantageous for reducing the wetting of the membrane. Additional mass transfer resistance was introduced by the superhydrophobic layer. In addition, continuous CO 2 absorption tests were carried out in original and modified PVDF hollow fibre membrane contactors, using monoethanolamine (MEA) solution as the absorbent. A long-term stability test revealed that the modified PVDF hollow fibre membrane contactor was able to outperform the original membrane contactor and demonstrated outstanding long-term stability, suggesting that spray deposition is a promising approach to obtain superhydrophobic PVDF membranes for liquid-gas membrane absorption.

Novel functionalized nano-TiO2 loading electrocatalytic membrane for oily wastewater treatment.

PubMed

Yang, Yang; Wang, Hong; Li, Jianxin; He, Benqiao; Wang, Tonghua; Liao, Shijun

2012-06-19

Membrane fouling is a critical problem in membrane filtration processes for water purification. Electrocatalytic membrane reactor (ECMR) was an effective method to avoid membrane fouling and improve water quality. This study focuses on the preparation and characterization of a novel functionalized nano-TiO(2) loading electrocatalytic membrane for oily wastewater treatment. A TiO(2)/carbon membrane used in the reactor is prepared by coating TiO(2) as an electrocatalyst via a sol-gel process on a conductive microporous carbon membrane. In order to immobilize TiO(2) on the carbon membrane, the carbon membrane is first pretreated with HNO(3) to generate the oxygen-containing functional groups on its surface. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS) analyses are used to evaluate the morphology and microstructure of the membranes. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements are employed to illustrate the eletrochemical activity of the TiO(2)/carbon membrane. The membrane performance is investigated by treating oily wastewater. The oil removal rate increases with a decrease in the liquid hourly space velocity (LHSV) through the ECMR. The COD removal rate was 100% with a LHSV of 7.2 h(-1) and 87.4% with a LHSV of 21.6 h(-1) during the treatment of 200 mg/L oily water. It suggests that the synergistic effect of electrocatalytic oxidation and membrane separation in the ECMR plays a key role.

Proton-conducting ionic liquid-based Proton Exchange Membrane Fuel Cell membranes: The key role of ionomer-ionic liquid interaction

NASA Astrophysics Data System (ADS)

Martinez, Mathieu; Molmeret, Yannick; Cointeaux, Laure; Iojoiu, Cristina; Leprêtre, Jean-Claude; El Kissi, Nadia; Judeinstein, Patrick; Sanchez, Jean-Yves

The paper deals with the synthesis and characterisation of proton-conducting ionic liquids (PCILs) and their polymer electrolytes obtained by blending modified Nafion membranes with different concentrations of PCILs. The PCILs are obtained by the neutralization of triethylamine with different organic acids. The first part of the paper studies the influence of acidity and acid structure on PCIL thermal and electrochemical performance, while the second part examines membrane conductivity and reveals it to depend more on PCIL structure than on its intrinsic conductivity. At 130 °C, conductivities exceeding 10 mS cm -1 were obtained in fully anhydrous conditions.

Membrane microreactors: gas-liquid reactions made easy.

PubMed

Noël, Timothy; Hessel, Volker

2013-03-01

Getting phases together: Membrane microreactors provide new opportunities for gas-liquid reactions. The advantages of this microreactor concept are a large interfacial area, a greater flexibility with regard to flow rates, and the opportunity to immobilize a catalyst on the membrane. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrokinetic migration across artificial liquid membranes Tuning the membrane chemistry to different types of drug substances.

PubMed

Gjelstad, Astrid; Rasmussen, Knut Einar; Pedersen-Bjergaard, Stig

2006-08-18

Twenty different basic drugs were electrokinetically extracted across a thin artificial organic liquid membrane with a 300 V d.c. electrical potential difference as the driving force. From a 300 microl aqueous sample (acidified corresponding to 10mM HCl), the drugs were extracted for 5 min through a 200 microm artificial liquid membrane of a water immiscible organic solvent immobilized in the pores of a polypropylene hollow fiber, and into a 30 microl aqueous acceptor solution of 10mM HCl inside the lumen of the hollow fiber. Hydrophobic basic drugs (logP>1.7) were effectively isolated utilizing 2-nitrophenyl octyl ether (NPOE) as the artificial liquid membrane, with recoveries up to 83%. For more hydrophilic basic drugs (logP<1.0), a mixture of NPOE and 25% (w/w) di-(2-ethylhexyl) phosphate (DEHP) was required to ensure efficient extraction, resulting in recoveries up to 75%. DEHP was expected to act as an ion-pair reagent ion-pairing the protonated hydrophilic drugs at the interface between the sample and the membrane, resulting in permeation of the interface.

First scientific application of the membrane cryostat technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montanari, David; Adamowski, Mark; Baller, Bruce R.

2014-01-29

We report on the design, fabrication, performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with IHI Corporation (IHI). Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon, and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the purity requirements in a membrane cryostat without evacuation and using only a controlled gaseous argon purge; to demonstrate that we canmore » achieve and maintain the purity requirements of the liquid argon during filling, purification, and maintenance mode using mole sieve and copper filters from the Liquid Argon Purity Demonstrator (LAPD) R and D project. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion oxygen equivalent. This paper gives the requirements, design, construction, and performance of the LBNE membrane cryostat prototype, with experience and results important to the development of the LBNE detector.« less

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

PubMed

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

2016-06-06

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

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

Fabrication of hemispherical liquid encapsulated structures based on droplet molding

NASA Astrophysics Data System (ADS)

Ishizuka, Hiroki; Miki, Norihisa

2015-12-01

We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

Novel magnetically induced membrane vibration (MMV) for fouling control in membrane bioreactors.

PubMed

Bilad, Muhammad R; Mezohegyi, Gergo; Declerck, Priscilla; Vankelecom, Ivo F J

2012-01-01

Conventional submerged membrane bioreactors (MBRs) rely on the coarse bubbles aeration to generate shear at the liquid-membrane interface to limit membrane fouling. Unfortunately, it is a very energy consuming method, still often resulting in a rapid decrease of membrane permeability and consequently in higher expenses. In this paper, the feasibility of a novel magnetically induced membrane vibration (MMV) system was studied in a lab-scale MBR treating synthetic wastewater. The effects on membrane fouling of applied electrical power of different operation strategies, of membrane flux and of the presence of multiple membranes on one vibrating engine on membrane fouling were investigated. The filtration performance was evaluated by determining the filtration resistance profiles and critical flux. The results showed clear advantages of the vibrating system over conventional MBR processes by ensuring higher fluxes at lower fouling rates. Intermittent vibration was found a promising strategy for both efficient fouling control and significant energy saving. The optimised MMV system is presumed to lead to significant energy and cost reduction in up-scaled MBR operations. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fouling of a spiral-wound reverse osmosis membrane processing swine wastewater: effect of cleaning procedure on fouling resistance.

PubMed

Camilleri-Rumbau, M S; Masse, L; Dubreuil, J; Mondor, M; Christensen, K V; Norddahl, B

2016-01-01

Swine manure is a valuable source of nitrogen, phosphorus and potassium. After solid-liquid separation, the resulting swine wastewater can be concentrated by reverse osmosis (RO) to produce a nitrogen-potassium rich fertilizer. However, swine wastewater has a high fouling potential and an efficient cleaning strategy is required. In this study, a semi-commercial farm scale RO spiral-wound membrane unit was fouled while processing larger volumes of swine wastewater during realistic cyclic operations over a 9-week period. Membrane cleaning was performed daily. Three different cleaning solutions, containing SDS, SDS+EDTA and NaOH were compared. About 99% of the fouling resistance could be removed by rinsing the membrane with water. Flux recoveries (FRs) above 98% were achieved for all the three cleaning solutions after cleaning. No significant differences in FR were found between the cleaning solutions. The NaOH solution thus is a good economical option for cleaning RO spiral-wound membranes fouled with swine wastewater. Soaking the membrane for 3 days in permeate water at the end of each week further improved the FR. Furthermore, a fouling resistance model for predicting the fouling rate, permeate flux decay and cleaning cycle periods based on processing time and swine wastewater conductivity was developed.

Membrane water-flow rate in electrolyzer cells with a solid polymer electrolyte (SPE)

NASA Astrophysics Data System (ADS)

Li, Xiaojin; Qu, Shuguo; Yu, Hongmei; Hou, Ming; Shao, Zhigang; Yi, Baolian

Water-flow rate across Nafion membrane in SPE electrolyzer cells was measured and modelled. From the analysis of water transport mechanisms in SPE water electrolysis, the water-flow rate through membrane can be described by the electro-osmotic drag. The calculated electro-osmotic drag coefficients, n d, for the membrane in SPE electrolysis cells at different temperatures were compared with literature and in good agreement with those of Ge et al. and Ise et al. To describe the water-flow rate through membrane more accurately, a linear fit of n d as a function of temperature for the membrane in SPE water electrolysis was proposed in this paper. This paper studied the membrane water-flow rate experimentally and mathematically, which is of importance in the designing and optimization of the process of SPE water electrolysis. This paper also provided a novel method for measuring the electro-osmotic drag coefficient of Nafion membrane in contact with liquid water, acid and methanol solutions, etc.

Hydraulically amplified PZT mems actuator

DOEpatents

Miles, Robin R.

2004-11-02

A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

Modifying Mechanical, Optical Properties and Thermal Processability of Iridescent Cellulose Nanocrystal Films Using Ionic Liquid.

PubMed

Liu, Ping; Guo, Xin; Nan, Fuchun; Duan, Yongxin; Zhang, Jianming

2017-01-25

Iridescent films formed from the self-assembly of cellulose nanocrystals (CNCs) are brittle and difficult to handle or integrate within an industrial process. Here we present a simple approach to prepare iridescent CNC films with tunable pliability and coloration through the addition of ionic liquids (ILs) of 1-allyl-3-methylimidazolium chloride (AmimCl) as plasticizers. By using the undried CNC film as a filter membrane and ILs solution as a leaching liquid, it was found that the filtration process made ILs uniformly interpenetrate into CNC film due to the strong ionic interaction between CNC and AmimCl. Unexpectedly, the filtration process also gave rise to partial desulfurization of CNC film, which is conducive to the improvement of thermal stability. Benefiting from the improved thermal stability and the dissolving capacity of AmimCl for cellulose at high temperature, the incorporated ILs enable the cholesteric CNC film to be further toughened via a hot-pressing treatment. This study demonstrates that ionic liquids have great potential to modify the mechanical, optical properties as well as the thermal stability of iridescent CNC films.

Morphological and electromechanical characterization of ionic liquid/Nafion polymer composites

NASA Astrophysics Data System (ADS)

Bennett, Matthew; Leo, Donald

2005-05-01

Ionic liquids have shown promise as replacements for water in ionic polymer transducers. Ionic liquids are non-volatile and have a larger electrochemical stability window than water. Therefore, transducers employing ionic liquids can be operated for long periods of time in air and can be actuated with higher voltages. Furthermore, transducers based on ionic liquids do not exhibit the characteristic back relaxation that is common with water-swollen materials. However, the physics of transduction in the ionic liquid-swollen materials is not well understood. In this paper, the morphology of Nafion/ionic liquid composites is characterized using small-angle X-ray scattering (SAXS). The electromechanical transduction behavior of the composites is also investigated. For this testing, five different counterions and two ionic liquids are used. The results reveal that both the morphology and transduction performance of the composites is affected by the identity of the ionic liquid, the cation, and the swelling level of ionic liquid within the membrane. Specifically, speed of response is found to be lower for the membranes that were exchanged with the smaller lithium and potassium ions. The response speed is also found to increase with increased content of ionic liquid. Furthermore, for the two ionic liquids studied, the actuators swollen with the less viscous ionic liquid exhibited a slower response. The slower speed of response corresponds to less contrast between the ionically conductive phase and the inert phase of the polymer. This suggests that disruption of the clustered morphology in the ionic liquid-swollen membranes as compared to water-swollen membranes attenuates ion mobility within the polymer. This attenuation is attributed to swelling of the non-conductive phase by the ionic liquids.

Flexible robust binder-free carbon nanotube membranes for solid state and microcapacitor application

NASA Astrophysics Data System (ADS)

Adu, Kofi; Ma, Danhao; Wang, Yuxiang; Spencer, Michael; Rajagopalan, Ramakrishnan; Wang, C.-Yu; Randall, Clive

2018-01-01

We present a liquid phase post synthesis self-assemble protocol that transforms trillions of carbon nanotubes (CNTs) in powder form into densely packed flexible, robust and binder-free macroscopic membranes with a hierarchical pore structure. We employ charge transfer engineering to spontaneously disperse the CNTs in a liquid medium. The processing protocol has limited or no impact on the intrinsic properties of the CNTs. As the thickness of the CNT membrane is increased, we observed a gradual transition from high flexibility to buckling and brittleness in the flexural properties of the membranes. The binder-free CNT membranes have bulk mass density greater than that of water (1.0 g cm-3). We correlate the mass of the CNTs in the membrane to the thickness of the membrane and obtained a bulk mass density of ˜1.11 g cm-3 ± 0.03 g cm-3. We demonstrate the use of the CNT membranes as electrode in a pristine and oxidized single/stacked solid-state capacitor as well as pristine interdigitated microcapacitor that show time constant of ˜32 ms with no degradation in performance even after 10 000 cycles. The capacitors show very good temperature dependence over a wide range of temperatures with good cycling performance up to 90 °C. The specific capacitance of the pseudocapacitive CNT electrode at room temperature was 72 F g-1 and increased to 100 F g-1 at 70 °C. The leakage current of bipolar stacked solid state capacitor was ˜100 nA cm-2 at 2.5 V when held for 72 h.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fauzi, Iqbal, E-mail: arcana@chem.itb.ac.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id

Recently, the need of secondary battery application continues to increase. The secondary battery which using a liquid electrolyte was indicated had some weakness. A solid polymer electrolyte is an alternative electrolytes membrane which developed in order to replace the liquid electrolyte type. In the present study, the effect of phosphorylation on to polymer electrolyte membrane which synthesized from chitosan and lithium perchlorate salts was investigated. The effect of the component’s composition respectively on the properties of polymer electrolyte, was carried out by analyzed of it’s characterization such as functional groups, ion conductivity, and thermal properties. The mechanical properties i.e tensilemore » resistance and the morphology structure of membrane surface were determined. The phosphorylation processing of polymer electrolyte membrane of chitosan and lithium perchlorate was conducted by immersing with phosphoric acid for 2 hours, and then irradiated on a microwave for 60 seconds. The degree of deacetylation of chitosan derived from shrimp shells was obtained around 75.4%. Relative molecular mass of chitosan was obtained by viscometry method is 796,792 g/mol. The ionic conductivity of chitosan membrane was increase from 6.33 × 10{sup −6} S/cm up to 6.01 × 10{sup −4} S/cm after adding by 15 % solution of lithium perchlorate. After phosphorylation, the ionic conductivity of phosphorylated lithium chitosan membrane was observed 1.37 × 10{sup −3} S/cm, while the tensile resistance of 40.2 MPa with a better thermal resistance. On the strength of electrolyte membrane properties, this polymer electrolyte membrane was suggested had one potential used for polymer electrolyte in field of lithium battery applications.« less

How To Functionalize Ceramics by Perfluoroalkylsilanes for Membrane Separation Process? Properties and Application of Hydrophobized Ceramic Membranes.

PubMed

Kujawa, Joanna; Cerneaux, Sophie; Kujawski, Wojciech; Bryjak, Marek; Kujawski, Jan

2016-03-23

The combination of microscopic (atomic force microscopy and scanning electron microscopy) and goniometric (static and dynamic measurements) techniques, and surface characterization (surface free energy determination, critical surface tension, liquid entry pressure, hydraulic permeability) was implemented to discuss the influence of perfluoroalkylsilanes structure and grafting time on the physicochemistry of the created hydrophobic surfaces on the titania ceramic membranes of 5 kD and 300 kD. The impact of molecular structure of perfluoroalkylsilanes modifiers (possessing from 6 to 12 carbon atoms in the fluorinated part of the alkyl chain) and the time of the functionalization process in the range of 5 to 35 h was studied. Based on the scanning electron microscopy with energy-dispersive X-ray spectroscopy, it was found that the localization of grafting molecules depends on the membrane pore size (5 kD or 300 kD). In the case of 5 kD titania membranes, modifiers are attached mainly on the surface and only partially inside the membrane pores, whereas, for 300 kD membranes, the perfluoroalkylsilanes molecules are present within the whole porous structure of the membranes. The application of 4 various types of PFAS molecules enabled for interesting observations and remarks. It was explained how to obtain ceramic membrane surfaces with controlled material (contact angle, roughness, contact angle hysteresis) and separation properties. Highly hydrophobic surfaces with low values of contact angle hysteresis and low roughness were obtained. These surfaces possessed also low values of critical surface tension, which means that surfaces are highly resistant to wetting. This finding is crucial in membrane applicability in separation processes. The obtained and characterized hydrophobic membranes were subsequently applied in air-gap membrane distillation processes. All membranes were very efficient in MD processes, showing good transport and selective properties (∼99% of NaCl salt rejection). Depending on the membrane pore size and used modifiers, the permeate flux was in the range of 0.5-4.5 kg·m(-2)·h(-1) and 0.3-4.2 kg·m(-2)·h(-1) for 5 kD and 300 kD membranes, respectively.

Osmotically-driven membrane processes for water reuse and energy recovery

NASA Astrophysics Data System (ADS)

Achilli, Andrea

Osmotically-driven membrane processes are an emerging class of membrane separation processes that utilize concentrated brines to separate liquid streams. Their versatility of application make them an attractive alternative for water reuse and energy production/recovery. This work focused on innovative applications of osmotically-driven membrane processes. The novel osmotic membrane bioreactor (OMBR) system for water reuse was presented. Experimental results demonstrated high sustainable flux and relatively low reverse diffusion of solutes from the draw solution into the mixed liquor. Membrane fouling was minimal and controlled with osmotic backwashing. The OMBR system was found to remove greater than 99% of organic carbon and ammonium-nitrogen. Forward osmosis (FO) can employ different draw solution in its process. More than 500 inorganic compounds were screened as draw solution candidates, the desktop screening process resulted in 14 draw solutions suitable for FO applications. The 14 draw solutions were then tested in the laboratory to evaluate water flux and reverse salt diffusion through the membrane. Results indicated a wide range of water flux and reverse salt diffusion depending on the draw solution utilized. Internal concentration polarization was found to lower both water flux and reverse salt diffusion by reducing the draw solution concentration at the interface between the support and dense layer of the membrane. A small group of draw solutions was found to be most suitable for FO processes with currently available FO membranes. Another application of osmotically-driven membrane processes is pressure retarded osmosis (PRO). PRO was investigated as a viable source of renewable energy. A PRO model was developed to predict water flux and power density under specific experimental conditions. The predictive model was tested using experimental results from a bench-scale PRO system. Previous investigations of PRO were unable to verify model predictions due to the lack of suitable membranes and membrane modules. In this investigation, for the first time, the use of a custom-made laboratory-scale membrane module enabled the collection of experimental PRO data. Results obtained with a flat-sheet cellulose triacetate FO membrane and NaCl feed and draw solutions closely matched model predictions. Power density was substantially reduced due to internal concentration polarization in the asymmetric membrane and, to a lesser degree, to salt passage. External concentration polarization was found to exhibit a relatively small effect on reducing the osmotic pressure driving force. Using the predictive PRO model, optimal membrane characteristics and module configuration can be determined in order to design a system specifically tailored for PRO processes.

Development of Nanostructured Water Treatment Membranes Based on Thermotropic Liquid Crystals: Molecular Design of Sub-Nanoporous Materials.

PubMed

Sakamoto, Takeshi; Ogawa, Takafumi; Nada, Hiroki; Nakatsuji, Koji; Mitani, Masato; Soberats, Bartolome; Kawata, Ken; Yoshio, Masafumi; Tomioka, Hiroki; Sasaki, Takao; Kimura, Masahiro; Henmi, Masahiro; Kato, Takashi

2018-01-01

Supply of safe fresh water is currently one of the most important global issues. Membranes technologies are essential to treat water efficiently with low costs and energy consumption. Here, the development of self-organized nanostructured water treatment membranes based on ionic liquid crystals composed of ammonium, imidazolium, and pyridinium moieties is reported. Membranes with preserved 1D or 3D self-organized sub-nanopores are obtained by photopolymerization of ionic columnar or bicontinuous cubic liquid crystals. These membranes show salt rejection ability, ion selectivity, and excellent water permeability. The relationships between the structures and the transport properties of water molecules and ionic solutes in the sub-nanopores in the membranes are examined by molecular dynamics simulations. The results suggest that the volume of vacant space in the nanochannel greatly affects the water and ion permeability.

New membranes based on ionic liquids for PEM fuel cells at elevated temperatures

NASA Astrophysics Data System (ADS)

Ye, H.; Huang, J.; Xu, J. J.; Kodiweera, N. K. A. C.; Jayakody, J. R. P.; Greenbaum, S. G.

Proton exchange membrane (PEM) fuel cells operating at elevated temperature, above 120 °C, will yield significant benefits but face big challenges for the development of suitable PEMs. The objectives of this research are to demonstrate the feasibility of the concept and realize [acid/ionic liquid/polymer] composite gel-type membranes as such PEMs. Novel membranes consisting of anhydrous proton solvent H 3PO 4, the protic ionic liquid PMIH 2PO 4, and polybenzimidazole (PBI) as a matrix have been prepared and characterized for PEM fuel cells intended for operation at elevated temperature (120-150 °C). Physical and electrochemical analyses have demonstrated promising characteristics of these H 3PO 4/PMIH 2PO 4/PBI membranes at elevated temperature. The proton transport mechanism in these new membranes has been investigated by Fourier transform infrared and nuclear magnetic resonance spectroscopic methods.

Development of Nanostructured Water Treatment Membranes Based on Thermotropic Liquid Crystals: Molecular Design of Sub‐Nanoporous Materials

PubMed Central

Ogawa, Takafumi; Nakatsuji, Koji; Mitani, Masato; Soberats, Bartolome; Kawata, Ken; Yoshio, Masafumi; Tomioka, Hiroki; Sasaki, Takao; Kimura, Masahiro

2017-01-01

Abstract Supply of safe fresh water is currently one of the most important global issues. Membranes technologies are essential to treat water efficiently with low costs and energy consumption. Here, the development of self‐organized nanostructured water treatment membranes based on ionic liquid crystals composed of ammonium, imidazolium, and pyridinium moieties is reported. Membranes with preserved 1D or 3D self‐organized sub‐nanopores are obtained by photopolymerization of ionic columnar or bicontinuous cubic liquid crystals. These membranes show salt rejection ability, ion selectivity, and excellent water permeability. The relationships between the structures and the transport properties of water molecules and ionic solutes in the sub‐nanopores in the membranes are examined by molecular dynamics simulations. The results suggest that the volume of vacant space in the nanochannel greatly affects the water and ion permeability. PMID:29375969

Separation of organic azeotropic mixtures by pervaporation. Final technical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.W.

1991-12-01

Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simplemore » distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center_dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.« less

Separation of organic azeotropic mixtures by pervaporation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.W.

1991-12-01

Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simplemore » distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.« less

Seeing through walls at the nanoscale: Microwave microscopy of enclosed objects and processes in liquids

DOE PAGES

Velmurugan, Jeyavel; Kalinin, Sergei V.; Kolmakov, Andrei; ...

2016-02-11

Here, noninvasive in situ nanoscale imaging in liquid environments is a current imperative in the analysis of delicate biomedical objects and electrochemical processes at reactive liquid–solid interfaces. Microwaves of a few gigahertz frequencies offer photons with energies of ≈10 μeV, which can affect neither electronic states nor chemical bonds in condensed matter. Here, we describe an implementation of scanning near-field microwave microscopy for imaging in liquids using ultrathin molecular impermeable membranes separating scanning probes from samples enclosed in environmental cells. We imaged a model electroplating reaction as well as individual live cells. Through a side-by-side comparison of the microwave imagingmore » with scanning electron microscopy, we demonstrate the advantage of microwaves for artifact-free imaging.« less

Novel antifouling nano-enhanced thin-film composite membrane containing cross-linkable acrylate-alumoxane nanoparticles for water softening.

PubMed

Ghaemi, Negin

2017-01-01

A novel thin-film composite (TFC) nanofiltration membrane was prepared using polymerization of pyrrole monomers on the PES ultrafiltration membrane. To improve the characteristics of hydrophobic polypyrrole (PPy) thin-film layer, cross-linkable acrylate-functionalized alumoxane nanoparticles with different concentrations were embedded into the thin-film during polymerization process, and thin-film nanocomposite (TFNC) membranes were prepared. The characteristics and performance of TFC and TFNC membranes were assessed through the morphological analyses (SEM, AFM), measurement of hydrophilicity and solid-liquid interfacial free energy, water permeability and Mg 2+ removal tests. Addition of proper amount of nanoparticles into the polymerization mixture led to the preparation of membranes with more hydrophilic, thinner and smoother active layer as well as higher water permeability compared to TFC control membrane. TFNC membrane prepared with 0.025g of nanoparticles was the most efficient membrane since it exhibited the highest rejection of MgCl 2 and MgSO 4 salts. Antifouling capability of membranes, in terms of flux recovery and fouling parameters, demonstrated the high tolerance of TFNC against fouling. Copyright © 2016 Elsevier Inc. All rights reserved.

Hollow fiber membrane based H₂ diffusion for efficient in situ biogas upgrading in an anaerobic reactor.

PubMed

Luo, Gang; Angelidaki, Irini

2013-04-01

Bubbleless gas transfer through a hollow fiber membrane (HFM) module was used to supply H2 to an anaerobic reactor for in situ biogas upgrading, and it creates a novel system that could achieve a CH4 content higher than 90 % in the biogas. The increase of CH4 content and pH, and the decrease of bicarbonate concentration were related with the increase of the H2 flow rate. The CH4 content increased from 78.4 % to 90.2 % with the increase of the H2 flow rate from 930 to 1,440 ml/(l  day), while the pH in the reactor remained below 8.0. An even higher CH4 content (96.1 %) was achieved when the H2 flow rate was increased to 1,760 ml/(l  day); however, the pH increased to around 8.3 due to bicarbonate consumption which hampered the anaerobic process. The biofilm formed on the HFM was found not to be beneficial for the process since it increased the resistance of H2 diffusion to the liquid. The study also demonstrated that the biofilm formed on the membrane only contributed 22-36 % to the H2 consumption, while most of the H2 was consumed by the microorganisms in the liquid phase.

Method of removing and detoxifying a phosphorus-based substance

DOEpatents

Vandegrift, G.F.; Steindler, M.J.

1985-05-21

A method of removing a phosphorus-based poisonous substance from water contaminated is presented. In addition, the toxicity of the phosphorus-based substance is also subsequently destroyed. A water-immiscible organic solvent is first immobilized on a supported liquid membrane before the contaminated water is contacted with one side of the supported liquid membrane to absorb the phosphorus-based substance in the organic solvent. The other side of the supported liquid membrane is contacted with a hydroxy-affording strong base to react with phosphorus-based solvated species to form a non-toxic product.

Combining blue native polyacrylamide gel electrophoresis with liquid chromatography tandem mass spectrometry as an effective strategy for analyzing potential membrane protein complexes of Mycobacterium bovis bacillus Calmette-Guérin

PubMed Central

2011-01-01

Background Tuberculosis is an infectious bacterial disease in humans caused primarily by Mycobacterium tuberculosis, and infects one-third of the world's total population. Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine has been widely used to prevent tuberculosis worldwide since 1921. Membrane proteins play important roles in various cellular processes, and the protein-protein interactions involved in these processes may provide further information about molecular organization and cellular pathways. However, membrane proteins are notoriously under-represented by traditional two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and little is known about mycobacterial membrane and membrane-associated protein complexes. Here we investigated M. bovis BCG by an alternative proteomic strategy coupling blue native PAGE to liquid chromatography tandem mass spectrometry (LC-MS/MS) to characterize potential protein-protein interactions in membrane fractions. Results Using this approach, we analyzed native molecular composition of protein complexes in BCG membrane fractions. As a result, 40 proteins (including 12 integral membrane proteins), which were organized in 9 different gel bands, were unambiguous identified. The proteins identified have been experimentally confirmed using 2-D SDS PAGE. We identified MmpL8 and four neighboring proteins that were involved in lipid transport complexes, and all subunits of ATP synthase complex in their monomeric states. Two phenolpthiocerol synthases and three arabinosyltransferases belonging to individual operons were obtained in different gel bands. Furthermore, two giant multifunctional enzymes, Pks7 and Pks8, and four mycobacterial Hsp family members were determined. Additionally, seven ribosomal proteins involved in polyribosome complex and two subunits of the succinate dehydrogenase complex were also found. Notablely, some proteins with high hydrophobicity or multiple transmembrane helixes were identified well in our work. Conclusions In this study, we utilized LC-MS/MS in combination with blue native PAGE to characterize modular components of multiprotein complexes in BCG membrane fractions. The results demonstrated that the proteomic strategy was a reliable and reproducible tool for analysis of BCG multiprotein complexes. The identification in our study may provide some evidence for further study of BCG protein interaction. PMID:21241518

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

NASA Technical Reports Server (NTRS)

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

2015-01-01

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

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

Performance and results of the LBNE 35 ton membrane cryostat prototype

DOE PAGES

Montanari, David; Adamowski, Mark; Hahn, Alan; ...

2015-07-15

We report on the performance and commissioning of the first membrane cryostat to be used for scientific application. The Long Baseline Neutrino Experiment (LBNE) has designed and fabricated a membrane cryostat prototype in collaboration with Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI). LBNE has designed and fabricated the supporting cryogenic system infrastructure and successfully commissioned and operated the first membrane cryostat. Original goals of the prototype are: to demonstrate the membrane cryostat technology in terms of thermal performance, feasibility for liquid argon and leak tightness; to demonstrate that we can remove all the impurities from the vessel and achieve the puritymore » requirements in a membrane cryostat without evacuation; to demonstrate that we can achieve and maintain the purity requirements of the liquid argon using mol sieve and copper filters. The purity requirements of a large liquid argon detector such as LBNE are contaminants below 200 parts per trillion (ppt) oxygen equivalent. LBNE is planning the design and construction of a large liquid argon detector. This presentation will present requirements, design and construction of the LBNE 35 ton membrane cryostat prototype, and detail the commissioning and performance. The experience and results of this prototype are extremely important for the development of the LBNE detector.« less

Percutaneous absorption of sunscreen agents from liquid paraffin: self-association of octyl salicylate and effects on skin flux.

PubMed

Jiang, R; Roberts, M S; Prankerd, R J; Benson, H A

1997-07-01

This study provides an investigation of the availability of octyl salicylate (OS), a common sunscreen agent, from liquid paraffin and the effect of OS on skin permeability. A model membrane system to isolate the vehicle effect from membrane permeability has been developed. Partitioning of OS between liquid paraffin and aqueous receptor phases was conducted. Partition coefficients increased with increase in OS concentration. A range of OS concentrations in liquid paraffin was diffused across human epidermis and synthetic membranes into 4% bovine serum albumin in phosphate-buffered saline and 50% ethanol. Absorption profiles of OS obtained from silicone and low-density polyethylene (LDPE) membranes were similar to each other but higher than for the high-density polyethylene [HDPE (3 times)] membrane and human epidermis (15 times). The steady state fluxes and apparent permeability coefficients (Kp') obtained from the diffusion studies showed the same trends with all membranes, except for the HDPE membrane which showed greater increase in flux and Kp' at concentrations above 30%. IR spectra showed that several bands of OS were shifted with concentrations, and the molecular models further suggested that the main contribution to the self-association is from non-1,4 van der Waals interactions.

Ionic Liquid Confined in Mesoporous Polymer Membrane with Improved Stability for CO2/N2 Separation

PubMed Central

Tan, Ming; Lu, Jingting; Zhang, Yang; Jiang, Heqing

2017-01-01

Supported ionic liquid membranes (SILMs) have a promising prospect of application in flue gas separation, owing to its high permeability and selectivity of CO2. However, existing SILMs have the disadvantage of poor stability due to the loss of ionic liquid from the large pores of the macroporous support. In this study, a novel SILM with high stability was developed by confining ionic liquid in a mesoporous polymer membrane. First, a mesoporous polymer membrane derived from a soluble, low-molecular-weight phenolic resin precursor was deposited on a porous Al2O3 support, and then 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]) was immobilized inside mesopores of phenolic resin, forming the SILM under vacuum. Effects of trans-membrane pressure difference on the SILM separation performance were investigated by measuring the permeances of CO2 and N2. The SILM exhibits a high ideal CO2/N2 selectivity of 40, and an actual selectivity of approximately 25 in a mixed gas (50% CO2 and 50% N2) at a trans-membrane pressure difference of 2.5 bar. Compared to [emim][BF4] supported by polyethersulfone membrane with a pore size of around 0.45 μm, the [emim][BF4] confined in a mesoporous polymer membrane exhibits an improved stability, and its separation performance remained stable for 40 h under a trans-membrane pressure difference of 1.5 bar in a mixed gas before the measurement was intentionally stopped. PMID:28961187

Membrane-Based Technologies in the Pharmaceutical Industry and Continuous Production of Polymer-Coated Crystals/Particles.

PubMed

Chen, Dengyue; Sirkar, Kamalesh K; Jin, Chi; Singh, Dhananjay; Pfeffer, Robert

2017-01-01

Membrane technologies are of increasing importance in a variety of separation and purification applications involving liquid phases and gaseous mixtures. Although the most widely used applications at this time are in water treatment including desalination, there are many applications in chemical, food, healthcare, paper and petrochemical industries. This brief review is concerned with existing and emerging applications of various membrane technologies in the pharmaceutical and biopharmaceutical industry. The goal of this review article is to identify important membrane processes and techniques which are being used or proposed to be used in the pharmaceutical and biopharmaceutical operations. How novel membrane processes can be useful for delivery of crystalline/particulate drugs is also of interest. Membrane separation technologies are extensively used in downstream processes for bio-pharmaceutical separation and purification operations via microfiltration, ultrafiltration and diafiltration. Also the new technique of membrane chromatography allows efficient purification of monoclonal antibodies. Membrane filtration techniques of reverse osmosis and nanofiltration are being combined with bioreactors and advanced oxidation processes to treat wastewaters from pharmaceutical plants. Nanofiltration with organic solvent-stable membranes can implement solvent exchange and catalyst recovery during organic solvent-based drug synthesis of pharmaceutical compounds/intermediates. Membranes in the form of hollow fibers can be conveniently used to implement crystallization of pharmaceutical compounds. The novel crystallization methods of solid hollow fiber cooling crystallizer (SHFCC) and porous hollow fiber anti-solvent crystallization (PHFAC) are being developed to provide efficient methods for continuous production of polymer-coated drug crystals in the area of drug delivery. This brief review provides a general introduction to various applications of membrane technologies in the pharmaceutical/biopharmaceutical industry with special emphasis on novel membrane techniques for pharmaceutical applications. The method of coating a drug particle with a polymer using the SHFCC method is stable and ready for scale-up for operation over an extended period. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Specific Adhesion of Lipid Membranes Can Simultaneously Produce Two Types of Lipid and Protein Heterogeneities

NASA Astrophysics Data System (ADS)

Shindell, Orrin; Micah, Natalie; Ritzer, Max; Gordon, Vernita

2015-03-01

Living cells adhere to one another and their environment. Adhesion is associated with re-organization of the lipid and protein components of the cell membrane. The resulting heterogeneities are functional structures involved in biological processes. We use artificial lipid membranes that contain a single type of binding protein. Before adhesion, the lipid, protein, and dye components in the membrane are well-mixed and constitute a single disordered-liquid phase (Ld) . After adhesion, two distinct types of heterogeneities coexist in the adhesion zone: a central domain of ordered lipid phase that excludes both binding proteins and membrane dye, and a peripheral domain of disordered lipid phase that is densely packed with adhesion proteins and enriched in membrane dye relative to the non-adhered portion of the vesicle. Thus, we show that adhesion that is mediated by only one type of protein can organize the lipid and protein components of the membranes into heterogeneities that resemble those found in biology, for example the immune synapse.

Catalyzed CO.sub.2-transport membrane on high surface area inorganic support

DOEpatents

Liu, Wei

2014-05-06

Disclosed are membranes and methods for making the same, which membranes provide improved permeability, stability, and cost-effective manufacturability, for separating CO.sub.2 from gas streams such as flue gas streams. High CO.sub.2 permeation flux is achieved by immobilizing an ultra-thin, optionally catalyzed fluid layer onto a meso-porous modification layer on a thin, porous inorganic substrate such as a porous metallic substrate. The CO.sub.2-selective liquid fluid blocks non-selective pores, and allows for selective absorption of CO.sub.2 from gas mixtures such as flue gas mixtures and subsequent transport to the permeation side of the membrane. Carbon dioxide permeance levels are in the order of 1.0.times.10.sup.-6 mol/(m.sup.2sPa) or better. Methods for making such membranes allow commercial scale membrane manufacturing at highly cost-effective rates when compared to conventional commercial-scale CO.sub.2 separation processes and equipment for the same and such membranes are operable on an industrial use scale.

Manipulating membrane lipid profiles to restore T-cell function in autoimmunity.

PubMed

Waddington, Kirsty E; Jury, Elizabeth C

2015-08-01

Plasma membrane lipid rafts are heterogeneous cholesterol and glycosphingolipid (GSL)-enriched microdomains, within which the tight packing of cholesterol with the saturated-acyl chains of GSLs creates a region of liquid-order relative to the surrounding disordered membrane. Thus lipid rafts govern the lateral mobility and interaction of membrane proteins and regulate a plethora of signal transduction events, including T-cell antigen receptor (TCR) signalling. The pathways regulating homoeostasis of membrane cholesterol and GSLs are tightly controlled and alteration of these metabolic processes coincides with immune cell dysfunction as is evident in atherosclerosis, cancer and autoimmunity. Indeed, membrane lipid composition is emerging as an important factor influencing the ability of cells to respond appropriately to microenvironmental stimuli. Consequently, there is increasing interest in targeting membrane lipids or their metabolic control as a novel therapeutic approach to modulate immune cell behaviour and our recent work demonstrates that this is a promising strategy in T-cells from patients with the autoimmune disease systemic lupus erythematosus (SLE). © 2015 Authors; published by Portland Press Limited.

Low energy consumption vortex wave flow membrane bioreactor.

PubMed

Wang, Zhiqiang; Dong, Weilong; Hu, Xiaohong; Sun, Tianyu; Wang, Tao; Sun, Youshan

2017-11-01

In order to reduce the energy consumption and membrane fouling of the conventional membrane bioreactor (MBR), a kind of low energy consumption vortex wave flow MBR was exploited based on the combination of biofilm process and membrane filtration process, as well as the vortex wave flow technique. The experimental results showed that the vortex wave flow state in the membrane module could be formed when the Reynolds number (Re) of liquid was adjusted between 450 and 1,050, and the membrane flux declined more slowly in the vortex wave flow state than those in the laminar flow state and turbulent flow state. The MBR system was used to treat domestic wastewater under the condition of vortex wave flow state for 30 days. The results showed that the removal efficiency for CODcr and NH 3 -N was 82% and 98% respectively, and the permeate quality met the requirement of 'Water quality standard for urban miscellaneous water consumption (GB/T 18920-2002)'. Analysis of the energy consumption of the MBR showed that the average energy consumption was 1.90 ± 0.55 kWh/m 3 (permeate), which was only two thirds of conventional MBR energy consumption.

A facile approach toward multifunctional polyethersulfone membranes via in situ cross-linked copolymerization.

PubMed

Sun, Chuangchao; Ji, Haifeng; Qin, Hui; Nie, Shengqiang; Zhao, Weifeng; Zhao, Changsheng

2015-01-01

In this study, multifunctional polyethersulfone (PES) membranes are prepared via in situ cross-linked copolymerization coupled with a liquid-liquid phase separation technique. Acrylic acid (AA) and N-vinylpyrrolidone (VP) are copolymerized in PES solution, and the solution is then directly used to prepare PES membranes. The infrared and X-ray photoelectron spectroscopy testing, scanning electron microscopy, and water contact angle measurements confirm the successful modification of pristine PES membrane. Protein adsorption, platelet adhesion, plasma recalcification time, and activated partial thromboplastin time assays convince that the modified PES membranes have a better biocompatibility than pristine PES membrane. In addition, the modified membranes showed good protein antifouling property and significant adsorption property of cationic dye. The loading of Ag nanoparticles into the modified membranes endows the composite membranes with antibacterial activity.

Lyotropic liquid crystalline L3 phase silicated nanoporous monolithic composites and their production

DOEpatents

McGrath, Kathryn M.; Dabbs, Daniel M.; Aksay, Ilhan A.; Gruner, Sol M.

2003-10-28

A mesoporous ceramic material is provided having a pore size diameter in the range of about 10-100 nanometers produced by templating with a ceramic precursor a lyotropic liquid crystalline L.sub.3 phase consisting of a three-dimensional, random, nonperiodic network packing of a multiple connected continuous membrane. A preferred process for producing the inesoporous ceramic material includes producing a template of a lyotropic liquid crystalline L.sub.3 phase by mixing a surfactant, a co-surfactant and hydrochloric acid, coating the template with an inorganic ceramic precursor by adding to the L.sub.3 phase tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS) and then converting the coated template to a ceramic by removing any remaining liquids.

Hollow fibre liquid phase micro-extraction by facilitated anionic exchange for the determination of flavonoids in faba beans (Vicia faba L.).

PubMed

Chaieb, Nadia; López-Mesas, Montserrat; Luis González, Johannes; Mars, Messaoud; Valiente, Manuel

2015-01-01

Flavonoids are polyphenolic compounds found ubiquitously in foods of plant origin. They are commonly extracted from plant materials with ethanol, methanol, water, their combination or even with acidified extracting solutions. The disadvantages of these methods are the use of high quantity of organic solvent, the possible loss of analytes in the different steps and the laborious process of the techniques. In addition, the complexity of the phenolic mixtures present in plant materials requires a preliminary clean-up and fractionation of the crude extracts. To develop a hollow fibre liquid phase micro-extraction (HF-LPME) method for a one step clean-up and pre-concentration of flavonoids. Two flavonoids (catechin and rutin) has been extracted by HF-LPME and analysed by HPLC. The related driving force for the liquid membrane has been studied by means of facilitated and non-facilitated transport. Different ionic and non-ionic water insoluble compounds [trioctylamine (TOA), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO) and methyltrioctylammonium chloride (aliquat 336)] were used as carriers. The liquid membrane was constituted by a solution of n-decanol in the presence or absence of carriers. Maximum enrichment factors were obtained with n-decanol/aliquat 336 (20%) as organic liquid membrane, sodium hydroxide (NaOH) (0.1 M) as donor solution, sodium chloride (NaCl) (2 M) as acceptor solution and 3 h as extraction time. Under these conditions, good results for validation parameters were obtained [for linearity, limit of detection (LOD), limit of quantitation (LOQ) and repeatability]. The developed method is simple, effective and has been successfully applied to determine catechin and rutin in ethanolic extracts of faba beans. Copyright © 2015 John Wiley & Sons, Ltd.

Transport properties of proton-exchange membranes: Effect of supercritical-fluid processing and chemical functionality

NASA Astrophysics Data System (ADS)

Pulido Ayazo

NafionRTM membranes commonly used in direct methanol fuel cells (DMFC), are tipically limited by high methanol permeability (also known as the cross-over limitation). These membranes have phase segregated sulfonated ionic domains in a perfluorinated backbone, which makes processing challenging and limited by phase equilibria considerations. This study used supercritical fluids (SCFs) as a processing alternative, since the gas-like mass transport properties of SCFs allow a better penetration into the membranes and the use of polar co-solvents influenced their morphology, fine-tuning the physical and transport properties in the membrane. Measurements of methanol permeability and proton conductivity were performed to the NafionRTM membranes processed with SCFs at 40ºC and 200 bar and the co-solvents as: acetone, tetrahydrofuran (THF), isopropyl alcohol, HPLC-grade water, acetic acid, cyclohexanone. The results obtained for the permeability data were of the order of 10 -8-10-9 cm2/s, two orders of magnitude lower than unprocessed Nafion. Proton conductivity results obtained using AC impedance electrochemical spectroscopy was between 0.02 and 0.09 S/cm, very similar to the unprocessed Nafion. SCF processing with ethanol as co-solvent reduced the methanol permeability by two orders of magnitude, while the proton conductivity was only reduced by 4%. XRD analysis made to the treated samples exhibited a decreasing pattern in the crystallinity, which affects the transport properties of the membrane. Also, SAXS profiles of the Nafion membranes processed were obtained with the goal of determining changes produced by the SCF processing in the hydrophilic domains of the polymer. With the goal of searching for new alternatives in proton exchange membranes (PEMs) triblock copolymer of poly(styrene-isobutylene-styrene) (SIBS) and poly(styrene-isobutylene-styrene) SEBS were studied. These sulfonated tri-block copolymers had lower methanol permeabilities, but also lower proton conductivity, even with blends of these and blends with Nafion membranes. Other alternative studied was the functionalization of the membranes SIBS with metallic cations, which decreased the methanol permeability in the membranes containing the cations Mg2+, Zn2+ and Al 3+, while the proton conductivity was maintained more or less constant. The permeation of methanol vapor was investigated and the behavior through the membranes studied followed a pattern of Fick's Law, while the pattern shown by the permeation in liquid phase was non-Fickian.

Stripping of acetone from water with microfabricated and membrane gas-liquid contactors.

PubMed

Constantinou, Achilleas; Ghiotto, Francesco; Lam, Koon Fung; Gavriilidis, Asterios

2014-01-07

Stripping of acetone from water utilizing nitrogen as a sweeping gas in co-current flow was conducted in a microfabricated glass/silicon gas-liquid contactor. The chip consisted of a microchannel divided into a gas and a liquid chamber by 10 μm diameter micropillars located next to one of the channel walls. The channel length was 35 mm, the channel width was 220 μm and the microchannel depth 100 μm. The micropillars were wetted by the water/acetone solution and formed a 15 μm liquid film between them and the nearest channel wall, leaving a 195 μm gap for gas flow. In addition, acetone stripping was performed in a microchannel membrane contactor, utilizing a hydrophobic PTFE membrane placed between two microstructured acrylic plates. Microchannels for gas and liquid flows were machined in the plates and had a depth of 850 μm and 200 μm respectively. In both contactors the gas/liquid interface was stabilized: in the glass/silicon contactor by the hydrophilic micropillars, while in the PTFE/acrylic one by the hydrophobic membrane. For both contactors separation efficiency was found to increase by increasing the gas/liquid flow rate ratio, but was not affected when increasing the inlet acetone concentration. Separation was more efficient in the microfabricated contactor due to the very thin liquid layer employed.

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

PubMed

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

2016-05-25

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

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)

Small unilamellar liposomes as a membrane model for cell inactivation by cold atmospheric plasma treatment

NASA Astrophysics Data System (ADS)

Maheux, S.; Frache, G.; Thomann, J. S.; Clément, F.; Penny, C.; Belmonte, T.; Duday, D.

2016-09-01

Cold atmospheric plasma is thought to be a promising tool for numerous biomedical applications due to its ability to generate a large diversity of reactive species in a controlled way. In some cases, it can also generate pulsed electric fields at the zone of treatment, which can induce processes such as electroporation in cell membranes. However, the interaction of these reactive species and the pulse electric field with cells in a physiological medium is very complex, and we still need a better understanding in order to be useful for future applications. A way to reach this goal is to work with model cell membranes such as liposomes, with the simplest physiological liquid and in a controlled atmosphere in order to limit the number of parallel reactions and processes. In this paper, where this approach has been chosen, 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) small unilamellar vesicles (SUV) have been synthesized in a phosphate buffered aqueous solution, and this solution has been treated by a nanosecond pulsed plasma jet under a pure nitrogen atmosphere. It is only the composition of the plasma gas that has been changed in order to generate different cocktails of reactive species. After the quantification of the main plasma reactive species in the phosphate buffered saline (PBS) solution, structural, surface charge state, and chemical modifications generated on the plasma treated liposomes, due to the interaction with the plasma reactive species, have been carefully characterized. These results allow us to further understand the effect of plasma reactive species on model cell membranes in physiological liquids. The permeation through the liposomal membrane and the reaction of plasma reactive species with molecules encapsulated inside the liposomes have also been evaluated. New processes of degradation are finally presented and discussed, which come from the specific conditions of plasma treatment under the pure nitrogen atmosphere.

Optical stretching as a tool to investigate the mechanical properties of lipid bilayers.

PubMed

Solmaz, Mehmet E; Sankhagowit, Shalene; Biswas, Roshni; Mejia, Camilo A; Povinelli, Michelle L; Malmstadt, Noah

2013-10-07

Measurements of lipid bilayer bending modulus by various techniques produce widely divergent results. We attempt to resolve some of this ambiguity by measuring bending modulus in a system that can rapidly process large numbers of samples, yielding population statistics. This system is based on optical stretching of giant unilamellar vesicles (GUVs) in a microfluidic dual-beam optical trap (DBOT). The microfluidic DBOT system is used here to measure three populations of GUVs with distinct lipid compositions. We find that gel-phase membranes are significantly stiffer than liquid-phase membranes, consistent with previous reports. We also find that the addition of cholesterol does not alter the bending modulus of membranes composed of a monounsaturated phospholipid.

Cholesterol affects the interaction between an ionic liquid and phospholipid vesicles. A study by differential scanning calorimetry and nanoplasmonic sensing.

PubMed

Russo, Giacomo; Witos, Joanna; Rantamäki, Antti H; Wiedmer, Susanne K

2017-12-01

The present work aims at studying the interactions between cholesterol-rich phosphatidylcholine-based lipid vesicles and trioctylmethylphosphonium acetate ([P 8881 ][OAc]), a biomass dissolving ionic liquid (IL). The effect of cholesterol was assayed by using differential scanning calorimetry (DSC) and nanoplasmonic sensing (NPS) measurement techniques. Cholesterol-enriched dipalmitoyl-phosphatidylcholine vesicles were exposed to different concentrations of the IL, and the derived membrane perturbation was monitored by DSC. The calorimetric data could suggest that the binding and infiltration of the IL are delayed in the vesicles containing cholesterol. To clarify our findings, NPS was applied to quantitatively follow the resistance of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine incorporating 0, 10, and 50mol% of cholesterol toward the IL exposure over time. The membrane perturbation induced by different concentrations of IL was found to be a concentration dependent process on cholesterol-free lipid vesicles. Moreover, our results showed that lipid depletion in cholesterol-enriched lipid vesicles is inversely proportional to the increasing amount of cholesterol in the vesicles. These findings support that cholesterol-rich lipid bilayers are less susceptible toward membrane disrupting agents as compared to membranes that do not incorporate any sterols. This probably occurs because cholesterol tightens the phospholipid acyl chain packing of the plasma membranes, increasing their resistance and reducing their permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular dynamics simulation of membrane in room temperature ionic liquids

NASA Astrophysics Data System (ADS)

Theng, Soong Guan; Jumbri, Khairulazhar bin; Wirzal, Mohd Dzul Hakim

2017-10-01

The polyvinylidene difluoride (PVDF) membrane has been a popular material in membrane separation process. In this work, molecular dynamic simulation was done on the PVDF membrane with 100 wt% IL and 50 wt% IL in GROningen MAchine for Chemical Simulations (GROMACS). The results was evaluated based on potential energy, root mean square deviation (RMSD) and radial distribution function (RDF). The stability and interaction of PVDF were evaluated. Results reveal that PVDF has a stronger interaction to [C2bim]+ cation compared to water and bromine anion. Both potential energy and RMSD were lower when the weight percentage of IL is higher. This indicates that the IL is able to stabilize the PVDF structure. RMSD reveals that [C2bim]+ cation is dominant at short distance (less than 1 nm), indicating that strong interaction of cation to PVDF. This understanding of the behavior of PVDF-IL could be used as a reference for future development of stronger membrane.

Mechanically Tunable, Readily Processable Ion Gels by Self-Assembly of Block Copolymers in Ionic Liquids.

PubMed

Lodge, Timothy P; Ueki, Takeshi

2016-01-01

Room temperature ionic liquids are of great interest for many advanced applications, due to the combination of attractive physical properties with essentially unlimited tunability of chemical structure. High chemical and thermal stability, favorable ionic conductivity, and complete nonvolatility are just some of the most important physical characteristics that make ionic liquids promising candidates for emerging technologies. Examples include separation membranes, actuators, polymer gel electrolytes, supercapacitors, ion batteries, fuel cell membranes, sensors, printable plastic electronics, and flexible displays. However, in these and other applications, it is essential to solidify the ionic liquid, while retaining the liquid state properties of interest. A broadly applicable solidification strategy relies on gelation by addition of suitable triblock copolymers with the ABA architecture, producing ion gels or ionogels. In this paradigm, the A end blocks are immiscible with the ionic liquid, and consequently self-assemble into micellar cores, while some fraction of the well-solvated B midblocks bridge between micelles, forming a percolating network. The chemical structures of the A and B repeat units, the molar mass of the blocks, and the concentration of the copolymer in the ionic liquid are all independently tunable to attain desired property combinations. In particular, the modulus of the resulting ion gel can be readily varied between 100 Pa and 1 MPa, with little sacrifice of the transport properties of the ionic liquid, such as ionic conductivity or gas diffusivity. Suitable A blocks can impart thermoreversible gelation (with solidification either on heating or cooling) or even photoreversible gelation. By virtue of the nonvolatility of ionic liquids, a wide range of processing strategies can be employed directly to prepare ion gels in thin or thick film forms, including solvent casting, spin coating, aerosol jet printing, photopatterning, and transfer printing. For higher modulus ion gels it is even possible to employ a manual "cut and stick" strategy for easy device fabrication. Ion gels prepared from common triblock copolymers, for example, with A = polystyrene and B = poly(ethylene oxide) or poly(methyl methacrylate), in imidazolium based ionic liquids provide exceptional performance in membranes for separating CO 2 from N 2 or CH 4 . The same materials also are the best available gate dielectrics for printed plastic electronics, because their high capacitance endows organic transistors with milliamp output currents for sub-1 V applied bias, with switching speeds that can go well beyond 100 kHz, while being amenable to large area roll-to-roll printing. Incorporation of well-designed electroluminescent (e.g., Ru(bpy) 3 -based) or electrochromic (e.g., viologen-based) moieties into ion gels held between transparent electrodes yields flexible color displays operating with sub-1 V dc inputs.

Ionic-liquid materials for the electrochemical challenges of the future.

PubMed

Armand, Michel; Endres, Frank; MacFarlane, Douglas R; Ohno, Hiroyuki; Scrosati, Bruno

2009-08-01

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Ionic-liquid materials for the electrochemical challenges of the future

NASA Astrophysics Data System (ADS)

Armand, Michel; Endres, Frank; Macfarlane, Douglas R.; Ohno, Hiroyuki; Scrosati, Bruno

2009-08-01

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Assembly and relaxation behaviours of phosphatidylethanolamine monolayers investigated by polarization and frequency resolved SFG-VS.

PubMed

Wei, Feng; Xiong, Wei; Li, Wenhui; Lu, Wangting; Allen, Heather C; Zheng, Wanquan

2015-10-14

The assembly conformation and kinetics of phosphatidylethanolamine (PE) lipids are the key to their membrane curvatures and activities, such as exocytosis, endocytosis and Golgi membrane fusion. In the current study, a polarization and frequency resolved (bandwidth ≈ 1 cm(-1)) picosecond sum frequency generation (SFG) system was developed to characterize phosphatidylethanolamine monolayers. In addition to obtaining π-A isotherms and Brewster angle microscopy (BAM) images, the conformational changes and assembly behaviors of phosphatidylethanolamine molecules are investigated by analyzing the SFG spectra collected at various surface pressures (SPs). The compression kinetics and relaxation kinetics of phosphatidylethanolamine monolayers are also reported. The conformational changes of PE molecules during the monolayer compression are separated into several stages: reorientation of the head group PO2(-) in the beginning of the liquid-expanded (LE) phase, conformational changes of head group alkyl chains in the LE phase, and conformational changes of tail group alkyl chains in the LE-liquid condensed (LE-LC) phase. Such an understanding may help researchers to effectively control the lipid molecular conformation and membrane curvatures during the exocytosis/endocytosis processes.

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

PubMed Central

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

2014-01-01

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. PMID:25501042

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

PubMed

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

2013-08-14

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

Direct methanol fuel cell and system

DOEpatents

Wilson, Mahlon S.

2004-10-26

A fuel cell having an anode and a cathode and a polymer electrolyte membrane located between anode and cathode gas diffusion backings uses a methanol vapor fuel supply. A permeable polymer electrolyte membrane having a permeability effective to sustain a carbon dioxide flux equivalent to at least 10 mA/cm.sup.2 provides for removal of carbon dioxide produced at the anode by reaction of methanol with water. Another aspect of the present invention includes a superabsorpent polymer material placed in proximity to the anode gas diffusion backing to hold liquid methanol or liquid methanol solution without wetting the anode gas diffusion backing so that methanol vapor from the liquid methanol or liquid methanol-water solution is supplied to the membrane.

Microgravity

NASA Image and Video Library

1995-09-12

DCAM, developed by MSFC, grows crystals by the dialysis and liquid-liquid diffusion methods. In both methods, protein crystal growth is induced by changing conditions in the protein. In dialysis, a semipermeable membrane retains the protein solution in one compartment, while allowing molecules of precipitant to pass freely through the membrane from an adjacent compartment. As the precipitant concentration increases within the protein compartment, crystallization begins. In liquid-liquid diffusion, a protein solution and a precipitant solution are layered in a container and allowed to diffuse into each other. This leads to conditions which may induce crystallization of the protein. Liquid-liquid diffusion is difficult on Earth because density and temperature differences cause the solutions to mix rapidly.

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.

Interleaflet Coupling, Pinning, and Leaflet Asymmetry—Major Players in Plasma Membrane Nanodomain Formation

PubMed Central

Fujimoto, Toyoshi; Parmryd, Ingela

2017-01-01

The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence. PMID:28119914

Interleaflet Coupling, Pinning, and Leaflet Asymmetry-Major Players in Plasma Membrane Nanodomain Formation.

PubMed

Fujimoto, Toyoshi; Parmryd, Ingela

2016-01-01

The plasma membrane has a highly asymmetric distribution of lipids and contains dynamic nanodomains many of which are liquid entities surrounded by a second, slightly different, liquid environment. Contributing to the dynamics is a continuous repartitioning of components between the two types of liquids and transient links between lipids and proteins, both to extracellular matrix and cytoplasmic components, that temporarily pin membrane constituents. This make plasma membrane nanodomains exceptionally challenging to study and much of what is known about membrane domains has been deduced from studies on model membranes at equilibrium. However, living cells are by definition not at equilibrium and lipids are distributed asymmetrically with inositol phospholipids, phosphatidylethanolamines and phosphatidylserines confined mostly to the inner leaflet and glyco- and sphingolipids to the outer leaflet. Moreover, each phospholipid group encompasses a wealth of species with different acyl chain combinations whose lateral distribution is heterogeneous. It is becoming increasingly clear that asymmetry and pinning play important roles in plasma membrane nanodomain formation and coupling between the two lipid monolayers. How asymmetry, pinning, and interdigitation contribute to the plasma membrane organization is only beginning to be unraveled and here we discuss their roles and interdependence.

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®.

Impact of polymeric membrane filtration of oil sands process water on organic compounds quantification.

PubMed

Moustafa, Ahmed M A; Kim, Eun-Sik; Alpatova, Alla; Sun, Nian; Smith, Scott; Kang, Seoktae; Gamal El-Din, Mohamed

2014-01-01

The interaction between organic fractions in oil sands process-affected water (OSPW) and three polymeric membranes with varying hydrophilicity (nylon, polyvinylidene fluoride and polytetrafluoroethylene) at different pHs was studied to evaluate the impact of filtration on the quantification of acid-extractable fraction (AEF) and naphthenic acids (NAs). Four functional groups predominated in OSPW (amine, phosphoryl, carboxyl and hydroxyl) as indicated by the linear programming method. The nylon membranes were the most hydrophilic and exhibited the lowest AEF removal at pH of 8.7. However, the adsorption of AEF on the membranes increased as the pH of OSPW decreased due to hydrophobic interactions between the membrane surfaces and the protonated molecules. The use of ultra pressure liquid chromatography-high resolution mass spectrometry (UPLC/HRMS) showed insignificant adsorption of NAs on the tested membranes at pH 8.7. However, 26±2.4% adsorption of NAs was observed at pH 5.3 following the protonation of NAs species. For the nylon membrane, excessive carboxylic acids in the commercial NAs caused the formation of negatively charged assisted hydrogen bonds, resulting in increased adsorption at pH 8.2 (25%) as compared to OSPW (0%). The use of membranes for filtration of soluble compounds from complex oily wastewaters before quantification analysis of AEF and NAs should be examined prior to application.

Membrane separation systems---A research and development needs assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, R.W.; Cussler, E.L.; Eykamp, W.

1990-03-01

Membrane based separation technology, a relative newcomer on the separations scene, has demonstrated the potential of saving enormous amounts of energy in the processing industries if substituted for conventional separation systems. Over 1 quad annually, out of 2.6, can possibly be saved in liquid-to-gas separations, alone, if membrane separation systems gain wider acceptance, according to a recent DOE/OIP (DOE/NBM-80027730 (1986)) study. In recent years great strides have been made in the field and offer even greater energy savings in the future when substituted for other conventional separation techniques such as distillation, evaporation, filtration, sedimentation, and absorption. An assessment was conductedmore » by a group of six internationally known membrane separations experts who examined the worldwide status of research in the seven major membrane areas. This encompassed four mature technology areas: reverse osmosis, micorfiltration, ultrafiltration, and electrodialysis; two developing areas: gas separation and and pervaporation; and one emerging technology: facilitated transport. Particular attention was paid to identifying the innovative processes currently emerging, and even further improvements which could gain wider acceptance for the more mature membrane technology. The topics that were pointed out as having the greatest research emphasis are pervaporation for organic-organic separations; gas separation; micorfiltration; an oxidant-resistant reverse osmosis membrane; and a fouling-resistant ultrafiltration membrane. 35 refs., 6 figs., 22 tabs.« less

A hollow-fiber membrane extraction process for recovery and separation of lactic acid from aqueous solution.

PubMed

Huang, Hanjing; Yang, Shang-Tian; Ramey, David E

2004-01-01

An energy-efficient hollow-fiber membrane extraction process was successfully developed to separate and recover lactic acid produced in fermentation. Although many fermentation processes have been developed for lactic acid production, an economical method for lactic acid recovery from the fermentation broth is still needed. Continuous extraction of lactic acid from a simulated aqueous stream was achieved by using Alamine 336 in 2-octanol contained in a hollow-fiber membrane extractor. In this process, the extractant was simultaneously regenerated by stripping with NaOH in a second membrane extractor, and the final product is a concentrated lactate salt solution. The extraction rate increased linearly with an increase in the Alamine 336 content in the solvent (from 5 to 40%). Increasing the concentration of the undissociated lactic acid in the feed solution by either increasing the lactate concentration (from 5 to 40 g/L) or decreasing the solution pH (from 5.0 to 4.0) also increased the extraction rate. Based on these observations, a reactive extraction model with a first-order reaction mechanism for both lactic acid and amine concentrations was proposed. The extraction rate also increased with an increase in the feed flow rate, but not the flow rates of solvent and the stripping solution, suggesting that the process was not limited by diffusion in the liquid films or membrane pores. A mathematical model considering both diffusion and chemical reaction in the extractor and back extractor was developed to simulate the process. The model fits the experimental data well and can be used in scale up design of the process.

Physics of transduction in ionic liquid-swollen Nafion membranes

NASA Astrophysics Data System (ADS)

Bennett, Matthew; Leo, Donald

2006-03-01

Ionic polymer transducers are a class of electroactive polymers that are able to generate large strains (1-5%) in response to low voltage inputs (1-5 V). Additionally, these materials generate electrical charge in response to mechanical strain and are therefore able to operate as soft, distributed sensors. Traditionally, ionic polymer transducers have been limited in their application by their hydration dependence. This work seeks to overcome this limitation by replacing the water with an ionic liquid. Ionic liquids are molten salts that exhibit very high thermal and electrochemical stability while also possessing high ionic conductivity. Results have shown that an ionic liquid-swollen ionic polymer transducer can operate for more than 250,000 cycles in air as compared to about 2,000 cycles for a water-swollen transducer. The current work examines the mechanisms of transduction in ionic liquid-swollen transducers based on Nafion polymer membranes. Specifically, the morphology and relevant ion associations within these membranes are investigated by the use of small-angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). These results reveal that the ionic liquid interacts with the membrane in much the same way that water does, and that the counterions of the Nafion polymer are the primary charge carriers. The results of these analyses are compared to the macroscopic transduction behavior in order to develop a model of the charge transport mechanism responsible for electromechanical coupling in these membranes.

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

DOEpatents

Kozubal, Eric Joseph

2016-12-13

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

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

DOEpatents

Kozubal, Eric Joseph; Slayzak, Steven Joseph

2014-07-08

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

Recovery of [CO2]T from Aqueous Bicarbonate using a Gas Permeable Membrane

DTIC Science & Technology

2008-06-25

pores as a function of differential partial gas pressures. Therefore it has been assumed for gas/ liquid systems that only the dissolved carbon dioxide...and pressure [10]. Gas permeable membranes are available commercially for the removal or addition of gases to liquids . Most of these applications...measurements were conducted with a standardized Fisher combination glass electrode. A microporous polypropylene membrane commercially designated as 2400

Dynamics of Nafion membrane swelling in H2O/D2O mixtures as studied using FTIR technique

NASA Astrophysics Data System (ADS)

Bunkin, Nikolai F.; Kozlov, Valeriy A.; Shkirin, Alexey V.; Ninham, Barry W.; Balashov, Anatoliy A.; Gudkov, Sergey V.

2018-03-01

Experiments with Fourier transform spectrometry of Nafion, a water-swollen polymeric membrane, are described. The transmittance spectra of liquid samples and Nafion, soaked in these samples, were studied, depending on the deuterium content in water in the spectral range 1.8-2.15 μm. The experiments were carried out using two protocols: in the first protocol we studied the dynamics of Nafion swelling in H2O + D2O mixtures for the deuterium concentrations 3 < C < 104 ppm, and in the second protocol we studied the dynamics of swelling in pure heavy water (C = 106 ppm). For liquid mixtures in the concentration range 3 < C < 104 ppm, the transmittance spectra are the same, but for Nafion soaked in these fluids, the corresponding spectra are different. It is shown that, in the range of deuterium contents C = 90-500 ppm, the behavior of transmittance of the polymer membrane is non-monotonic. In experiments using the second protocol, the dynamics of diffusion replacement of residual water, which is always present in the bulk of the polymer membrane inside closed cavities (i.e., without access to atmospheric air), were studied. The experimentally estimated diffusion coefficient for this process is ≈6.10-11 cm2/s.

Automated sample preparation using membrane microtiter extraction for bioanalytical mass spectrometry.

PubMed

Janiszewski, J; Schneider, P; Hoffmaster, K; Swyden, M; Wells, D; Fouda, H

1997-01-01

The development and application of membrane solid phase extraction (SPE) in 96-well microtiter plate format is described for the automated analysis of drugs in biological fluids. The small bed volume of the membrane allows elution of the analyte in a very small solvent volume, permitting direct HPLC injection and negating the need for the time consuming solvent evaporation step. A programmable liquid handling station (Quadra 96) was modified to automate all SPE steps. To avoid drying of the SPE bed and to enhance the analytical precision a novel protocol for performing the condition, load and wash steps in rapid succession was utilized. A block of 96 samples can now be extracted in 10 min., about 30 times faster than manual solvent extraction or single cartridge SPE methods. This processing speed complements the high-throughput speed of contemporary high performance liquid chromatography mass spectrometry (HPLC/MS) analysis. The quantitative analysis of a test analyte (Ziprasidone) in plasma demonstrates the utility and throughput of membrane SPE in combination with HPLC/MS. The results obtained with the current automated procedure compare favorably with those obtained using solvent and traditional solid phase extraction methods. The method has been used for the analysis of numerous drug prototypes in biological fluids to support drug discovery efforts.

Purification and proteomic analysis of plant plasma membranes.

PubMed

Alexandersson, Erik; Gustavsson, Niklas; Bernfur, Katja; Karlsson, Adine; Kjellbom, Per; Larsson, Christer

2008-01-01

All techniques needed for proteomic analyses of plant plasma membranes are described in detail, from isolation of plasma membranes to protein identification by mass spectrometry (MS). Plasma membranes are isolated by aqueous two-phase partitioning yielding vesicles with a cytoplasmic side-in orientation and a purity of about 95%. These vesicles are turned inside-out by treatment with Brij 58, which removes soluble contaminating proteins enclosed in the vesicles as well as loosely attached proteins. The final plasma membrane preparation thus retains all integral proteins and many peripheral proteins. Proteins are separated by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein bands are excised and digested with trypsin. Peptides in tryptic digests are separated by nanoflow liquid chromatography and either fed directly into an ESI-MS or spotted onto matrix-assisted laser desorption ionization (MALDI) plates for analysis with MALDI-MS. Finally, data processing and database searching are used for protein identification to define a plasma membrane proteome.

Change in the fouling propensity of sludge in membrane bioreactors (MBR) in relation to the accumulation of biopolymer clusters.

PubMed

Sun, Fei-yun; Wang, Xiao-mao; Li, Xiao-yan

2011-04-01

A membrane bioreactor (MBR) and an activated sludge process (ASP) were operated side by side to evaluate the change of sludge supernatant characteristics and the evolution of the sludge fouling propensity. The MBR sludge had a higher organic concentration and more biopolymer clusters (BPC) in the supernatant compared with ASP. BPC increased in both concentration and size in the MBR. The results show that the change in the liquid-phase property had a profound effect on the sludge fouling propensity. MBR operation transformed typical activated sludge to MBR sludge with a higher fouling propensity. Distinct from the ASP, membrane filtration retained soluble microbial products (SMP) within the MBR, and the vast membrane surface provided a unique environment for the transformation of SMP to large size BPC, leading to further sludge deposition on the membrane surface. Thus, membrane filtration is the crucial cause of the inevitable fouling problem in submerged MBRs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Lipid Biomembrane in Ionic Liquids

NASA Astrophysics Data System (ADS)

Yoo, Brian; Jing, Benxin; Shah, Jindal; Maginn, Ed; Zhu, Y. Elaine; Department of Chemical and Biomolecular Engineering Team

2014-03-01

Ionic liquids (ILs) have been recently explored as new ``green'' chemicals in several chemical and biomedical processes. In our pursuit of understanding their toxicities towards aquatic and terrestrial organisms, we have examined the IL interaction with lipid bilayers as model cell membranes. Experimentally by fluorescence microscopy, we have directly observed the disruption of lipid bilayer by added ILs. Depending on the concentration, alkyl chain length, and anion hydrophobicity of ILs, the interaction of ILs with lipid bilayers leads to the formation of micelles, fibrils, and multi-lamellar vesicles for IL-lipid complexes. By MD computer simulations, we have confirmed the insertion of ILs into lipid bilayers to modify the spatial organization of lipids in the membrane. The combined experimental and simulation results correlate well with the bioassay results of IL-induced suppression in bacteria growth, thereby suggesting a possible mechanism behind the IL toxicity. National Science Foundation, Center for Research Computing at Notre Dame.

Local Area Water Removal Analysis of a Proton Exchange Membrane Fuel Cell under Gas Purge Conditions

PubMed Central

Lee, Chi-Yuan; Lee, Yu-Ming; Lee, Shuo-Jen

2012-01-01

In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold. PMID:22368495

Liquid nitrogen cryotherapy for lip mucous membrane venous malformation in infants.

PubMed

Zhang, Da-Ming; Wang, You-Yuan; Lin, Zhao-Yu; Yang, Zhao-Hui; Chen, Wei-Liang

2015-03-01

Lip mucous membrane venous malformations are common benign lesions in infants. This clinical study evaluates the efficacy and safety of liquid nitrogen cryotherapy used to treat this condition. A total of 84 pediatric patients undergoing liquid nitrogen cryotherapy for venous malformations involving the lips were reviewed, with 45 males and 39 females treated. The overall median age at mucous membrane venous malformation diagnosis was 5.6 months (range 2-18 months). The venous malformations involved the vermilion of the lower lip in 44 cases, the vermilion of the upper lip in 31 cases, and both vermilions in 9 cases. No complications due to anesthesia occurred. After a follow-up period of 2-38 months (mean 25 months), 65 lesions (77.4 %) were completely involuted, 14 lesions (16.7 %) were mostly involuted, and 5 lesions (5.9 %) were partially involuted; no lesions showed a minor amount of involution. Liquid nitrogen cryotherapy is an effective, simple, and safe management tool for mucous membrane venous malformations of the lip in infants.

Local area water removal analysis of a proton exchange membrane fuel cell under gas purge conditions.

PubMed

Lee, Chi-Yuan; Lee, Yu-Ming; Lee, Shuo-Jen

2012-01-01

In this study, local area water content distribution under various gas purging conditions are experimentally analyzed for the first time. The local high frequency resistance (HFR) is measured using novel micro sensors. The results reveal that the liquid water removal rate in a membrane electrode assembly (MEA) is non-uniform. In the under-the-channel area, the removal of liquid water is governed by both convective and diffusive flux of the through-plane drying. Thus, almost all of the liquid water is removed within 30 s of purging with gas. However, liquid water that is stored in the under-the-rib area is not easy to remove during 1 min of gas purging. Therefore, the re-hydration of the membrane by internal diffusive flux is faster than that in the under-the-channel area. Consequently, local fuel starvation and membrane degradation can degrade the performance of a fuel cell that is started from cold.

Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics.

PubMed

Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; Rehman, Aziz Ur

2015-07-08

The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy ( ∆G° ), enthalpy ( ∆H° ) and entropy ( ∆S° ) were calculated for the adsorption of congo red, indicating an exothermic process.

Removal of Congo Red from Aqueous Solution by Anion Exchange Membrane (EBTAC): Adsorption Kinetics and Themodynamics

PubMed Central

Khan, Muhammad Imran; Akhtar, Shahbaz; Zafar, Shagufta; Shaheen, Aqeela; Khan, Muhammad Ali; Luque, Rafael; ur Rehman, Aziz

2015-01-01

The adsorption behavior of anionic dye congo red (CR) from aqueous solutions using an anion exchange membrane (EBTAC) has been investigated at room temperature. The effect of several factors including contact time, membrane dosage, ionic strength and temperature were studied. Kinetic models, namely pseudo-first-order and pseudo-second-order, liquid film diffusion and Elovich models as well as Bangham and modified freundlich Equations, were employed to evaluate the experimental results. Parameters such as adsorption capacities, rate constant and related correlation coefficients for every model were calculated and discussed. The adsorption of CR on anion exchange membranes followed pseudo-second-order Kinetics. Thermodynamic parameters, namely changes in Gibbs free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were calculated for the adsorption of congo red, indicating an exothermic process. PMID:28793430

Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

DTIC Science & Technology

2011-09-30

transducers from branched sulfonated polysulfones.7 The mechanical strength of the membranes drastically decreased upon introduction of ionic liquids to... liquids ,8 and zwitterionomers maintained mechanical strengths upon swelling with 10 wt % ionic liquid . Zwitterions are chargedmolecules that contain...water purification5 to biotechnology.6 A unique combination of physical properties of ionomeric membranes is the ionic con- ductivity of lowmolar mass

Influence Of Zwitterions on Properties and Morphology of Ionomers: Implications for Electro-Active Applications

DTIC Science & Technology

2010-08-01

membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in composites with similar mechanical performance, but 1. REPORT DATE (DD-MM...TERMS zwitterionomer, thermal mechanical property, morphology, ionic liquid , ionic conductivity, transducer Tianyu Wu, Rebecca H. Brown, Andrew J. Duncan...expected entanglement concentration. Swelling of the zwitterionomer membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in

Furfural production in biphasic media using an acidic ionic liquid as a catalyst.

PubMed

Peleteiro, Susana; Santos, Valentín; Parajó, Juan C

2016-11-20

Ionic liquids are valuable tools for biorefineries. This study provides an experimental assessment on the utilization of an acidic ionic liquid (1-butyl-3-methylimidazolium hydrogen sulfate) as a catalyst for furfural production in water/solvent media. The substrates employed in experiments were commercial xylose (employed as a reference compound) or hemicellulosic saccharides obtained by hydrothermal processing of Eucalyptus globulus wood (which were employed as produced, after membrane concentration or after freeze-drying). A variety of reaction conditions (defined by temperature, reaction time and type of organic solvent) were considered. The possibility of recycling the catalyst was assessed in selected experiments. Copyright © 2016 Elsevier Ltd. All rights reserved.

NLS propulsion - Government view

NASA Technical Reports Server (NTRS)

Smelser, Jerry W.

1992-01-01

The paper discusses the technology development for the Space Transportation Main Engine (STME). The STME is a liquid oxygen/liquid hydrogen engine with 650,000 pounds of thrust, which may be flown in single-engine or multiple-engine configurations, depending upon the payload and mission requirements. The technological developments completed so far include a vacuum plasma spray process, the liquid interface diffusion bonding, and a thin membrane platelet technology for the combustion chamber fabrication; baseline designs for the hydrogen turbopump and the oxygen pump; and the engine control system. The family of spacecraft for which this engine is being developed includes a 20,000 pound payload to LEO and a 150,000 pound to LEO vehicle.

Method of retrieving a liquid sample, a suction lysimeter, a portable suction lysimeter, a lysimeter system, and a deep lysimeter

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2003-08-26

A method of retrieving a liquid sample comprises providing a portable lysimeter including a semi-permeable membrane and a chamber in fluid communication with the semi-permeable membrane; making a hole at a site from which a liquid sample is desired; evacuating the chamber by applying a vacuum to the chamber; lowering the portable lysimeter into the hole; obtaining a sample in the chamber; and retrieving the lysimeter from the bore; wherein it is not necessary to backfill the bore. A portable lysimeter includes a semi-permeable member and a chamber in fluid communication with the semi-permeable membrane.

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

PubMed

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

2016-12-01

The effects of ionic liquids on model phospholipid membranes were studied by small-angle X-ray scattering, dynamic light scattering (DLS) and zeta potential measurements. Multilamellar 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes and large unilamellar vesicles composed of l-α-phosphatidylcholine (eggPC) and l-α-phosphatidylglycerol (eggPG) (80:20mol%) or eggPC, eggPG, and cholesterol (60:20:20mol%) were used as biomimicking membrane models. The effects of the phosphonium-based ionic liquids: tributylmethylphosphonium acetate, trioctylmethylphosphonium acetate, tributyl(tetradecyl)-phosphonium acetate, and tributyl(tetradecyl)-phosphonium chloride, were compared to those of 1-ethyl-3-methyl-imidazolium acetate. With multilamellar vesicles, the ionic liquids that did not disrupt liposomes decreased the lamellar spacing as a function of concentration. The magnitude of the effect depended on concentration for all studied ionic liquids. Using large unilamellar vesicles, first a slight decrease in the vesicle size, then aggregation of vesicles was observed by DLS for increasing ionic liquid concentrations. At concentrations just below those that caused aggregation of liposomes, large unilamellar vesicles were coated by ionic liquid cations, evidenced by a change in their zeta potential. The ability of phosphonium-based ionic liquids to affect liposomes is related to the length of the hydrocarbon chains in the cation. Generally, the ability of ionic liquids to disrupt liposomes goes hand in hand with inducing disorder in the phospholipid membrane. However, trioctylmethylphosphonium acetate selectively extracted and induced a well-ordered lamellar structure in phospholipids from disrupted cholesterol-containing large unilamellar vesicles. This kind of effect was not seen with any other combination of ionic liquids and liposomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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.

Visualization of flow during cleaning process on a liquid nanofibrous filter

NASA Astrophysics Data System (ADS)

Bílek, P.

2017-10-01

This paper deals with visualization of flow during cleaning process on a nanofibrous filter. Cleaning of a filter is very important part of the filtration process which extends lifetime of the filter and improve filtration properties. Cleaning is carried out on flat-sheet filters, where particles are deposited on the filter surface and form a filtration cake. The cleaning process dislodges the deposited filtration cake, which is loose from the membrane surface to the retentate flow. The blocked pores in the filter are opened again and hydrodynamic properties are restored. The presented optical method enables to see flow behaviour in a thin laser sheet on the inlet side of a tested filter during the cleaning process. The local concentration of solid particles is possible to estimate and achieve new information about the cleaning process. In the article is described the cleaning process on nanofibrous membranes for waste water treatment. The hydrodynamic data were compared to the images of the cleaning process.

Phase Transitions in the Nucleus: the functional implications of concentration-dependent assembly of a Liquid-like RNA/Protein Body

NASA Astrophysics Data System (ADS)

Zhu, Lian; Weber, Stephanie; Berry, Joel; Vaidya, Nilesh; Haataja, Mikko; Brangwynne, Clifford

2015-03-01

The nucleolus is a liquid-like membrane-less nuclear body which plays an important role in cell growth and size control. By modulating nucleolar component concentration through RNAi conditions that change C. elegans cell size, we find that nucleoli only assemble above a threshold concentration; moreover, the ripening dynamics of nucleated droplets are consistent with the hypothesis that the assembly of the nucleolus represents an intracellular liquid-liquid phase transition. A key question is how this phase-transition is linked to the primary function of the nucleolus, in transcribing and processing ribosomal RNA. To address this, we characterize the localization of RNA Polymerase I, a key transcriptional enzyme, into nucleolar foci as a function of nucleolar component concentration. Our results suggest that there are a small number of key disordered phosphoproteins that may serve as a link between transcription and assembly. Finally, we present preliminary results using a reduced model system consisting of purified nucleolar proteins to assess the ability of nucleolar proteins to drive liquid-liquid phase separation in vitro. These results lay the foundation for a quantitative understanding of intracellular phase transitions and their impact on biomedically-critical RNA-processing steps.

Two-liquid-phase bioreactors.

PubMed

Van Sonsbeek, H M; Beeftink, H H; Tramper, J

1993-09-01

The application of two liquid phases that are poorly miscible is a fascinating research topic for biocatalytical conversions because of the promising results. Motives for application include an increase of productivity and achievement of continuous processing, but new limitations arise, e.g., interfacial effects such as biocatalyst accumulation and loss of activity, medium component accumulation, and slow coalescence. Centrifuges, membranes, and immobilization are tools that can overcome part of the problems, but more fundamental knowledge about interfaces and coalescence is still necessary for successful application. For scaleup and further development of processes based on the obtained results, a choice must be made for the configuration of the experimental setup of a bioreactor. Aspects like aeration, shear stress, batch or continuous processing, and immobilization can play an important role. This review article describes these aspects and the proposals that have been made in recent years concerning two-liquid-phase bioreactors. It shows some adaptations to existing bioreactors, such as loop reactors and stirred-tank reactors.

Formation and size distribution of self-assembled vesicles

PubMed Central

Huang, Changjin; Quinn, David; Suresh, Subra

2017-01-01

When detergents and phospholipid membranes are dispersed in aqueous solutions, they tend to self-assemble into vesicles of various shapes and sizes by virtue of their hydrophobic and hydrophilic segments. A clearer understanding of such vesiculation processes holds promise for better elucidation of human physiology and disease, and paves the way to improved diagnostics, drug development, and drug delivery. Here we present a detailed analysis of the energetics and thermodynamics of vesiculation by recourse to nonlinear elasticity, taking into account large deformation that may arise during the vesiculation process. The effects of membrane size, spontaneous curvature, and membrane stiffness on vesiculation and vesicle size distribution were investigated, and the critical size for vesicle formation was determined and found to compare favorably with available experimental evidence. Our analysis also showed that the critical membrane size for spontaneous vesiculation was correlated with membrane thickness, and further illustrated how the combined effects of membrane thickness and physical properties influenced the size, shape, and distribution of vesicles. These findings shed light on the formation of physiological extracellular vesicles, such as exosomes. The findings also suggest pathways for manipulating the size, shape, distribution, and physical properties of synthetic vesicles, with potential applications in vesicle physiology, the pathobiology of cancer and other diseases, diagnostics using in vivo liquid biopsy, and drug delivery methods. PMID:28265065

[Printing and dyeing wastewater treatment using combined process of anaerobic bioreactor and MBR].

PubMed

Zheng, Xiang; Liu, Jun-xin

2004-09-01

This paper describes a labor-scale experiment for printing and dyeing wastewater treatment of woolen mill using a combined process of an anaerobic reactor and a membrane bioreactor (MBR). The experimental results showed that when the concentration of COD, BOD5 and color in the influent were 128-321 mg/L, 36-95 mg/L and 40-70 dilution times (DT), the average concentrations of COD, BOD5, color and turbidity in the effluent were 36.9 mg/L, 3.7 mg/L, 21 DT and 0.24 NTU, respectively, and the corresponding removal rates were 80.3%, 95%, 59% and 99.3%, respectively. A new integrated membrane bioreactor by gravity drain of liquid level in the bioreactor was developed in this study. It not only lessens suction pump for effluent and controlling unit comparing to the traditional integrated membrane bioreactor, but also has the characters of high and continuous flux, concise configuration and simple operation and maintenance. According to the experimental results, the air flow rate through the membrane module is a significant factor to affect the flux rate and cake layer deposited on the membrane. With application of optimal air flow rate, it is effective to reduce membrane fouling and maintain high flux rate.

Ergosterol in POPC membranes: physical properties and comparison with structurally similar sterols.

PubMed

Hsueh, Ya-Wei; Chen, Mei-Ting; Patty, Philipus J; Code, Christian; Cheng, John; Frisken, Barbara J; Zuckermann, Martin; Thewalt, Jenifer

2007-03-01

The physical properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/ergosterol bilayers in the liquid-crystalline phase were determined using deuterium nuclear magnetic resonance ((2)H NMR) and vesicle extrusion. For the (2)H NMR experiments, the sn-1 chain of POPC was perdeuterated, and spectra were taken as a function of ergosterol concentration and temperature. Analysis of the liquid-crystalline spectra provides clear evidence that two types of liquid-crystalline domains, neither of which is a liquid-ordered phase, having distinct average chain conformations coexist in 80:20 and 75:25 POPC/ergosterol membranes over a wide temperature range (from -2 to at least 31 degrees C). Adding ergosterol to a concentration of 25 mol % increases POPC-d(31) chain ordering as measured by the NMR spectral first moment M(1) and also increases the membrane lysis tension, obtained from vesicle extrusion. Further addition of ergosterol had no effect on either chain order or lysis tension. This behavior is in marked contrast to the effect of cholesterol on POPC membranes: POPC/cholesterol membranes have a linear dependence of chain order on sterol concentration to at least 40 mol %. To investigate further we compared the dependence on sterol structure and concentration of the NMR spectra and lysis tension for several POPC/sterol membranes at 25 degrees C. For all POPC/sterol membranes investigated in this study, we observed a universal linear relation between lysis tension and M(1). This suggests that changes in acyl chain ordering directly affect the tensile properties of the membrane.

Ergosterol in POPC Membranes: Physical Properties and Comparison with Structurally Similar Sterols

PubMed Central

Hsueh, Ya-Wei; Chen, Mei-Ting; Patty, Philipus J.; Code, Christian; Cheng, John; Frisken, Barbara J.; Zuckermann, Martin; Thewalt, Jenifer

2007-01-01

The physical properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/ergosterol bilayers in the liquid-crystalline phase were determined using deuterium nuclear magnetic resonance (2H NMR) and vesicle extrusion. For the 2H NMR experiments, the sn-1 chain of POPC was perdeuterated, and spectra were taken as a function of ergosterol concentration and temperature. Analysis of the liquid-crystalline spectra provides clear evidence that two types of liquid-crystalline domains, neither of which is a liquid-ordered phase, having distinct average chain conformations coexist in 80:20 and 75:25 POPC/ergosterol membranes over a wide temperature range (from −2 to at least 31°C). Adding ergosterol to a concentration of 25 mol % increases POPC-d31 chain ordering as measured by the NMR spectral first moment M1 and also increases the membrane lysis tension, obtained from vesicle extrusion. Further addition of ergosterol had no effect on either chain order or lysis tension. This behavior is in marked contrast to the effect of cholesterol on POPC membranes: POPC/cholesterol membranes have a linear dependence of chain order on sterol concentration to at least 40 mol %. To investigate further we compared the dependence on sterol structure and concentration of the NMR spectra and lysis tension for several POPC/sterol membranes at 25°C. For all POPC/sterol membranes investigated in this study, we observed a universal linear relation between lysis tension and M1. This suggests that changes in acyl chain ordering directly affect the tensile properties of the membrane. PMID:17142279

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.

Hydration and dehydration cycles in polymer electrolyte fuel cells operated with wet anode and dry cathode feed: A neutron imaging and modeling study

NASA Astrophysics Data System (ADS)

García-Salaberri, P. A.; Sánchez, D. G.; Boillat, P.; Vera, M.; Friedrich, K. A.

2017-08-01

Proper water management plays an essential role in the performance and durability of Polymer Electrolyte Fuel Cells (PEFCs), but it is challenged by the variety of water transport phenomena that take place in these devices. Previous experimental work has shown the existence of fluctuations between low and high current density levels in PEFCs operated with wet hydrogen and dry air feed. The alternation between both performance states is accompanied by strong changes in the high frequency resistance, suggesting a cyclic hydration and dehydration of the membrane. This peculiar scenario is examined here considering liquid water distributions from neutron imaging and predictions from a 3D two-phase non-isothermal model. The results show that the hydration-dehydration cycles are triggered by the periodic condensation and shedding of liquid water at the anode inlet. The input of liquid water humidifies the anode channel and offsets the membrane dry-out induced by the dry air stream, thus leading to the high-performance state. When liquid water is flushed out of the anode channel, the dehydration process takes over, and the cell comes back to the low-performance state. The predicted amplitude of the current oscillations grows with decreasing hydrogen and increasing air flow rates, in agreement with previous experimental data.

Optical stretching as a tool to investigate the mechanical properties of lipid bilayers†

PubMed Central

Solmaz, Mehmet E.; Sankhagowit, Shalene; Biswas, Roshni; Mejia, Camilo A.; Povinelli, Michelle L.; Malmstadt, Noah

2013-01-01

Measurements of lipid bilayer bending modulus by various techniques produce widely divergent results. We attempt to resolve some of this ambiguity by measuring bending modulus in a system that can rapidly process large numbers of samples, yielding population statistics. This system is based on optical stretching of giant unilamellar vesicles (GUVs) in a microfluidic dual-beam optical trap (DBOT). The microfluidic DBOT system is used here to measure three populations of GUVs with distinct lipid compositions. We find that gel-phase membranes are significantly stiffer than liquid-phase membranes, consistent with previous reports. We also find that the addition of cholesterol does not alter the bending modulus of membranes composed of a monounsaturated phospholipid. PMID:24244843

AC impedance investigations of proton conduction in Nafion(sup TM)

NASA Astrophysics Data System (ADS)

Cahan, B. D.; Wainright, J. S.

1993-12-01

AC impedance spectroscopy has been employed to study the conduction of protons in Nafion 117 polymer electrolyte membrane. Both two- and four-electrode geometries have been used to uniquely distinguish between the membrane impedance and the interfacial impedances. The results show that the impedance of Nafion for frequencies up to 100 kHz is characterized by a pure resistance, similar to conventional liquid electrolytes. The frequency dependent features observed using a two-electrode geometry are shown to be consistent will well-characterized interfacial impedances and do not arise from ionic conduction in the membrane. These results show that previous two-electrode studies reported in the literature have misinterpreted the impedance of the electrode interfaces as belonging to the conduction process in the electrolyte.

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.

PubMed

Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

2008-01-01

Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Clare L; Haeussler, Wolfgang; Seydel, Tilo

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' dynamicalmore » 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.« less

Nonequilibrium fluctuations during diffusion in liquid layers

NASA Astrophysics Data System (ADS)

Brogioli, Doriano; Vailati, Alberto

2017-07-01

Theoretical analysis and experiments have provided compelling evidence of the presence of long-range nonequilibrium concentration fluctuations during diffusion processes in fluids. In this paper, we investigate the dependence of the features of the fluctuations from the dimensionality of the system. In three-dimensional fluids the amplitude of nonequilibrium fluctuations can become several orders of magnitude larger than that of equilibrium fluctuations. Notwithstanding that, the amplitude of nonequilibrium fluctuations remains small with respect to the concentration difference driving the diffusion process. By extending the theory to two-dimensional systems, such as liquid monolayers and bilayers, we show that the amplitude of the fluctuations becomes much stronger than in three-dimensional systems. We investigate the properties of the fronts of diffusion and show that they have a self-affine structure characterized by a Hurst exponent H =1 . We discuss the implications of these results for diffusion in liquid crystals and in cellular membranes of living organisms.

Nonequilibrium fluctuations during diffusion in liquid layers.

PubMed

Brogioli, Doriano; Vailati, Alberto

2017-07-01

Theoretical analysis and experiments have provided compelling evidence of the presence of long-range nonequilibrium concentration fluctuations during diffusion processes in fluids. In this paper, we investigate the dependence of the features of the fluctuations from the dimensionality of the system. In three-dimensional fluids the amplitude of nonequilibrium fluctuations can become several orders of magnitude larger than that of equilibrium fluctuations. Notwithstanding that, the amplitude of nonequilibrium fluctuations remains small with respect to the concentration difference driving the diffusion process. By extending the theory to two-dimensional systems, such as liquid monolayers and bilayers, we show that the amplitude of the fluctuations becomes much stronger than in three-dimensional systems. We investigate the properties of the fronts of diffusion and show that they have a self-affine structure characterized by a Hurst exponent H=1. We discuss the implications of these results for diffusion in liquid crystals and in cellular membranes of living organisms.

Overview of online two-dimensional liquid chromatography based on cell membrane chromatography for screening target components from traditional Chinese medicines.

PubMed

Muhammad, Saqib; Han, Shengli; Xie, Xiaoyu; Wang, Sicen; Aziz, Muhammad Majid

2017-01-01

Cell membrane chromatography is a simple, specific, and time-saving technique for studying drug-receptor interactions, screening of active components from complex mixtures, and quality control of traditional Chinese medicines. However, the short column life, low sensitivity, low column efficiency (so cannot resolve satisfactorily mixture of compounds), low peak capacity, and inefficient in structure identification were bottleneck in its application. Combinations of cell membrane chromatography with multidimensional chromatography such as two-dimensional liquid chromatography and high sensitivity detectors like mass have significantly reduced many of the above-mentioned shortcomings. This paper provides an overview of the current advances in online two-dimensional-based cell membrane chromatography for screening target components from traditional Chinese medicines with particular emphasis on the instrumentation, preparation of cell membrane stationary phase, advantages, and disadvantages compared to alternative approaches. The last section of the review summarizes the applications of the online two-dimensional high-performance liquid chromatography based cell membrane chromatography reported since its emergence to date (2010-June 2016). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Process for recovering organic vapors from air

DOEpatents

Baker, Richard W.

1985-01-01

A process for recovering and concentrating organic vapor from a feed stream of air having an organic vapor content of no more than 20,000 ppm by volume. A thin semipermeable membrane is provided which has a feed side and a permeate side, a selectivity for organic vapor over air of at least 50, as measured by the ratio of organic vapor permeability to nitrogen permeability, and a permeability of organic vapor of at least 3.times.10.sup.-7 cm.sup.3 (STP) cm/cm.sup.2 sec.cm Hg. The feed stream is passed across the feed side of the thin semipermeable membrane while providing a pressure on the permeate side which is lower than the feed side by creating a partial vacuum on the permeate side so that organic vapor passes preferentially through the membrane to form an organic vapor depleted air stream on the feed side and an organic vapor enriched stream on the permeate side. The organic vapor which has passed through the membrane is compressed and condensed to recover the vapor as a liquid.

Thermodynamic modelling of a membrane distillation crystallisation process for the treatment of mining wastewater.

PubMed

Nathoo, Jeeten; Randall, Dyllon Garth

2016-01-01

Membrane distillation (MD) could be applicable in zero liquid discharge applications. This is due to the fact that MD is applicable at high salinity ranges which are generally outside the scope of reverse osmosis (RO) applications, although this requires proper management of precipitating salts to avoid membrane fouling. One way of managing these salts is with MD crystallisation (MDC). This paper focuses on the applicability of MDC for the treatment of mining wastewater by thermodynamically modelling the aqueous chemistry of the process at different temperatures. The paper is based on the typical brine generated from an RO process in the South African coal mining industry and investigates the effect water recovery and operating temperature have on the salts that are predicted to crystallise out, the sequence in which they will crystallise out and purities as a function of the water recovery. The study confirmed the efficacy of using thermodynamic modelling as a tool for investigating and predicting the crystallisation aspects of the MDC process. The key finding from this work was that, for an MDC process, a purer product can be obtained at higher operating temperatures and recoveries because of the inverse solubility of calcium sulphate.

A fluidic device for the controlled formation and real-time monitoring of soft membranes self-assembled at liquid interfaces.

PubMed

Mendoza-Meinhardt, Arturo; Botto, Lorenzo; Mata, Alvaro

2018-02-13

Membrane materials formed at the interface between two liquids have found applications in a large variety of technologies, from sensors to drug-delivery and catalysis. However, studying the formation of these membranes in real-time presents considerable challenges, owing to the difficulty of prescribing the location and instant of formation of the membrane, the difficulty of observing time-dependent membrane shape and thickness, and the poor reproducibility of results obtained using conventional mixing procedures. Here we report a fluidic device that facilitates characterisation of the time-dependent thickness, morphology and mass transport properties of materials self-assembled at fluid-fluid interfaces. In the proposed device the membrane forms from the controlled coalescence of two liquid menisci in a linear open channel. The linear geometry and controlled mixing of the solutions facilitate real-time visualisation, manipulation and improve reproducibility. Because of its small dimensions, the device can be used in conjunction with standard microscopy methods and reduces the required volumes of potentially expensive reagents. As an example application to tissue engineering, we use the device to characterise interfacial membranes formed by supra-molecular self-assembly of peptide-amphiphiles with either an elastin-like-protein or hyaluronic acid. The device can be adapted to study self-assembling membranes for applications that extend beyond bioengineering.

Acyl transfer from membrane lipids to peptides is a generic process.

PubMed

Dods, Robert H; Bechinger, Burkhard; Mosely, Jackie A; Sanderson, John M

2013-11-15

The generality of acyl transfer from phospholipids to membrane-active peptides has been probed using liquid chromatography-mass spectrometry analysis of peptide-lipid mixtures. The peptides examined include melittin, magainin II, PGLa, LAK1, LAK3 and penetratin. Peptides were added to liposomes with membrane lipid compositions ranging from pure phosphatidylcholine (PC) to mixtures of PC with phosphatidylethanolamine, phosphatidylserine or phosphatidylglycerol. Experiments were typically conducted at pH7.4 at modest salt concentrations (90 mM NaCl). In favorable cases, lipidated peptides were further characterized by tandem mass spectrometry methods to determine the sites of acylation. Melittin and magainin II were the most reactive peptides, with significant acyl transfer detected under all conditions and membrane compositions. Both peptides were lipidated at the N-terminus by transfer from PC, phosphatidylethanolamine, phosphatidylserine or phosphatidylglycerol, as well as at internal sites: lysine for melittin; serine and lysine for magainin II. Acyl transfer could be detected within 3h of melittin addition to negatively charged membranes. The other peptides were less reactive, but for each peptide, acylation was found to occur in at least one of the conditions examined. The data demonstrate that acyl transfer is a generic process for peptides bound to membranes composed of diacylglycerophospholipids. Phospholipid membranes cannot therefore be considered as chemically inert toward peptides and by extension proteins. © 2013. Published by Elsevier Ltd. All rights reserved.

Oxygen-producing inert anodes for SOM process

DOEpatents

Pal, Uday B

2014-02-25

An electrolysis system for generating a metal and molecular oxygen includes a container for receiving a metal oxide containing a metallic species to be extracted, a cathode positioned to contact a metal oxide housed within the container; an oxygen-ion-conducting membrane positioned to contact a metal oxide housed within the container; an anode in contact with the oxygen-ion-conducting membrane and spaced apart from a metal oxide housed within the container, said anode selected from the group consisting of liquid metal silver, oxygen stable electronic oxides, oxygen stable crucible cermets, and stabilized zirconia composites with oxygen stable electronic oxides.

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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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…

The cuttlefish Sepia officinalis (Sepiidae, Cephalopoda) constructs cuttlebone from a liquid-crystal precursor

PubMed Central

Checa, Antonio G.; Cartwright, Julyan H. E.; Sánchez-Almazo, Isabel; Andrade, José P.; Ruiz-Raya, Francisco

2015-01-01

Cuttlebone, the sophisticated buoyancy device of cuttlefish, is made of extensive superposed chambers that have a complex internal arrangement of calcified pillars and organic membranes. It has not been clear how this structure is assembled. We find that the membranes result from a myriad of minor membranes initially filling the whole chamber, made of nanofibres evenly oriented within each membrane and slightly rotated with respect to those of adjacent membranes, producing a helical arrangement. We propose that the organism secretes a chitin–protein complex, which self-organizes layer-by-layer as a cholesteric liquid crystal, whereas the pillars are made by viscous fingering. The liquid crystallization mechanism permits us to homologize the elements of the cuttlebone with those of other coleoids and with the nacreous septa and the shells of nautiloids. These results challenge our view of this ultra-light natural material possessing desirable mechanical, structural and biological properties, suggesting that two self-organizing physical principles suffice to understand its formation. PMID:26086668

Faradaically selective membrane for liquid metal displacement batteries

NASA Astrophysics Data System (ADS)

Yin, Huayi; Chung, Brice; Chen, Fei; Ouchi, Takanari; Zhao, Ji; Tanaka, Nobuyuki; Sadoway, Donald R.

2018-02-01

In the realm of stationary energy storage, a plurality of candidate chemistries continues to vie for acceptance, among them the Na-NiCl2 displacement battery, which has eluded widespread adoption owing to the fragility of the β″-Al2O3 membrane. Here we report a porous electronically conductive membrane, which achieves chemical selectivity by preferred faradaic reaction instead of by regulated ionic conduction. Fitted with a porous membrane of TiN, a displacement cell comprising a liquid Pb positive electrode, a liquid Li-Pb negative electrode and a molten-salt electrolyte of PbCl2 dissolved in LiCl-KCl eutectic was cycled at a current density of 150 mA cm-2 at a temperature of 410 °C and exhibited a coulombic efficiency of 92% and a round-trip energy efficiency of 71%. As an indication of industrial scalability, we show comparable performance in a cell fitted with a faradaic membrane fashioned out of porous metal.

Enhanced proton transport in nanostructured polymer electrolyte/ionic liquid membranes under water-free conditions.

PubMed

Kim, Sung Yeon; Kim, Suhan; Park, Moon Jeong

2010-10-05

Proton exchange fuel cells (PEFCs) have the potential to provide power for a variety of applications ranging from electronic devices to transportation vehicles. A major challenge towards economically viable PEFCs is finding an electrolyte that is both durable and easily passes protons. In this article, we study novel anhydrous proton-conducting membranes, formed by incorporating ionic liquids into synthetic block co-polymer electrolytes, poly(styrenesulphonate-b-methylbutylene) (S(n)MB(m)), as high-temperature PEFCs. The resulting membranes are transparent, flexible and thermally stable up to 180 °C. The increases in the sulphonation level of S(n)MB(m) co-polymers (proton supplier) and the concentration of the ionic liquid (proton mediator) produce an overall increase in conductivity. Morphology effects were studied by X-ray scattering and electron microscopy. Compared with membranes having discrete ionic domains (including Nafion 117), the nanostructured membranes revealed over an order of magnitude increase in conductivity with the highest conductivity of 0.045 S cm(-1) obtained at 165 °C.

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.

Effects of DMSO and glycerol additives on the property of polyamide reverse osmosis membrane.

PubMed

Wu, Fengjing; Liu, Xiaojuan; Au, Chaktong

2016-10-01

The polyamide reverse osmosis (RO) membranes were prepared through interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). The use of dimethyl sulfoxide (DMSO) and glycerol as additives for the formation of thin-film composite (TFC) was investigated. We studied the effect of DMSO and glycerol addition on membrane property and RO performance. Microscopic morphology was examined by atomic force microscopy and scanning electron microscopy. The surface hydrophilicity was characterized on the basis of water contact angle and surface solid-liquid interfacial free energy (-ΔG SL ). Water flux and salt rejection ability of the membranes prepared with or without the additives were evaluated by cross-flow RO tests. The results reveal that the addition of DMSO and glycerol strongly influences the property of the TFC RO membrane. Compared to the MPD/TMC membrane fabricated without DMSO and glycerol, the MPD/TMC/DMSO/glycerol membrane has a rougher surface and is more hydrophilic, showing smaller water contact angle and larger -ΔG SL value. Without decrease in salt rejection ability, the MPD/TMC/DMSO/glycerol membrane shows water flux significantly larger than that of the MPD/TMC membrane. The unique property of the MPD/TMC/DMSO/glycerol membrane is attributed to the cooperative effect of DMSO and glycerol on membrane structure during the interfacial polymerization process.

Development of Advanced Membranes Technology Platform for Hydrocarbon Separations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalthod, Dr Dilip

2010-03-01

Virtually all natural gas is dehydrated during its production, transmission and storage, mostly by absorption processes. Membranes offer many potential advantages over absorption, including smaller footprints, lighter-weight packages, packaging flexibility, minimal electrical power duty, amenability to expansion due to system modularity, reduced maintenance costs, reduced emissions of heavy hydrocarbons, no liquid waste streams, and amenability to unmanned operation. The latter is particularly valuable because new natural gas sources are generally located in remote onshore and offshore sites. Most commercially-available membranes for natural gas upgrading involve high capital costs, high methane loss and performance degradation from operational upsets – all ofmore » which are barriers to their widespread adoption by the industry. The original focus of the project was to develop and demonstrate robust, high-performance membranes for natural gas dehydration. The first task completed was a user needs-and-wants study to 1) clarify the expectations of system fabricators and end users of the new separations equipment, and 2) establish the required technical and commercial targets for the membrane products. Following this, membrane system modeling and membrane development in the lab proceeded in parallel. Membrane module diameter and length, as well as and the fiber outer and inner fiber diameter, were optimized from a mathematical model that accounts for the relevant fluid dynamics and permeation phenomena. Module design was evaluated in the context of overall system design, capital costs and energy consumption, including the process scheme (particularly sweep generation), feed pretreatment, system layout, and process control. This study provided targets for membrane permeation coefficients and membrane geometry in a commercial offering that would be competitive with absorption systems. A commercially-available polymer with good tensile strength and chemical resistance was selected for membrane development. A novel dope composition and spinning process were developed, which provide a new approach to controlling membrane porosity and wall and skin morphology. A hollow-fiber membrane with an external dense “skin” was produced that has a high water vapor permeation coefficient and selectivity, durability when in operation at 1000 psig and 70°C, and the ability to withstand aromatic and aliphatic hydrocarbon vapors for an extended period. The fiber meets the technical requirements for a commercial product offering in gas dehydration. It can be readily manufactured with some changes in process equipment and process conditions, and is an excellent candidate for scale-up to full-size membrane modules.« less

Dynamics of the Glycophorin A Dimer in Membranes of Native-Like Composition Uncovered by Coarse-Grained Molecular Dynamics Simulations.

PubMed

Flinner, Nadine; Schleiff, Enrico

2015-01-01

Membranes are central for cells as borders to the environment or intracellular organelle definition. They are composed of and harbor different molecules like various lipid species and sterols, and they are generally crowded with proteins. The membrane system is very dynamic and components show lateral, rotational and translational diffusion. The consequence of the latter is that phase separation can occur in membranes in vivo and in vitro. It was documented that molecular dynamics simulations of an idealized plasma membrane model result in formation of membrane areas where either saturated lipids and cholesterol (liquid-ordered character, Lo) or unsaturated lipids (liquid-disordered character, Ld) were enriched. Furthermore, current discussions favor the idea that proteins are sorted into the liquid-disordered phase of model membranes, but experimental support for the behavior of isolated proteins in native membranes is sparse. To gain insight into the protein behavior we built a model of the red blood cell membrane with integrated glycophorin A dimer. The sorting and the dynamics of the dimer were subsequently explored by coarse-grained molecular dynamics simulations. In addition, we inspected the impact of lipid head groups and the presence of cholesterol within the membrane on the dynamics of the dimer within the membrane. We observed that cholesterol is important for the formation of membrane areas with Lo and Ld character. Moreover, it is an important factor for the reproduction of the dynamic behavior of the protein found in its native environment. The protein dimer was exclusively sorted into the domain of Ld character in the model red blood cell plasma membrane. Therefore, we present structural information on the glycophorin A dimer distribution in the plasma membrane in the absence of other factors like e.g. lipid anchors in a coarse grain resolution.

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 is incredible freedom in designing the block copolymer architecture in order to optimize the mechanical and other properties of the membrane without sacrificing conductivity. The derived scaling relationships are shown to be general for many block copolymer and ionic liquid chemistries. In certain cases, the mechanism of ion conduction in the ionic liquid is affected by block copolymer nanoconfinement. The introduction of excess neutral imidazole to [Im][TFSI] leads to enhanced proton conductivity as well as a high H+ transference number due to facilitated proton hopping between imidazole molecules. We show that there is increased proton hopping when the nonstoichiometric ionic liquid is confined to lamellar block copolymer nanodomains, which we hypothesize is due to changes in the hydrogen bond structure of the ionic liquid under confinement. This, in combination with unique ion aggregation behavior, leads to a lower activation energy for macroscopic ion transport compared to that in a corresponding homopolymer/ionic liquid mixture. Through this work, we further the understanding of the relationship between membrane composition, structure, and ion transport. The findings presented herein portend the rational design of nanostructured membranes having improved mechanical properties and conductivity.

Preparation of thermo-responsive membranes. II.

PubMed

Nozawa, I; Suzuki, Y; Sato, S; Sugibayashi, K; Morimoto, Y

1991-05-01

Two types of liquid crystal (LC)-immobilized membranes were prepared by a soaking method and sandwich method to control the permeation of indomethacin, as a model drug, in response to local and systemic fever. Monooxyethylene trimethylolpropane tristearate (MTTS) was used as a model LC because it has a gel-liquid crystal phase transition temperature near the body temperature, 39-40 degrees C in phosphate buffered saline (pH 7.4). Two porous polypropylene (PP) membranes were soaked into 20% MTTS chloroform solution in the soaking method, and two PP membranes were poured with the melted MTTS and pressed in the sandwich method. Thermo-response efficacy of the soaked membrane was dependent upon the content of MTTS in MTTS membrane, and the MTTS content above the void volume of PP membrane (38%) was needed for high efficacy. On the other hand, the sandwich membrane exhibited higher thermo-response efficacy than the soaked membrane, because more LC was embedded in the pores of sandwich membrane than that of the soaked membrane. The sandwich membrane permeation of indomethacin was sharply controlled by temperature changes between 32 and 38 degrees C.

Methods and apparatus for using gas and liquid phase cathodic depolarizers

NASA Technical Reports Server (NTRS)

Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

1998-01-01

The invention provides methods for using gas and liquid phase cathodic depolarizers in an electrochemical cell having a cation exchange membrane in intimate contact with the anode and cathode. The electrochemical conversion of cathodic depolarizers at the cathode lowers the cell potential necessary to achieve a desired electrochemical conversion, such as ozone evolution, at the anode. When gaseous cathodic depolarizers, such as oxygen, are used, a gas diffusion cathode having the cation exchange membrane bonded thereto is preferred. When liquid phase cathodic depolarizers are used, the cathode may be a flow-by electrode, flow-through electrode, packed-bed electrode or a fluidized-bed electrode in intimate contact with the cation exchange membrane.

Pressurized diesel fuel processing using hydrogen peroxide for the fuel cell power unit in low-oxygen environments

NASA Astrophysics Data System (ADS)

Lee, Kwangho; Han, Gwangwoo; Cho, Sungbaek; Bae, Joongmyeon

2018-03-01

A novel concept for diesel fuel processing utilizing H2O2 is suggested to obtain the high-purity H2 required for air-independent propulsion using polymer electrolyte membrane fuel cells for use in submarines and unmanned underwater vehicles. The core components include 1) a diesel-H2O2 autothermal reforming (ATR) reactor to produce H2-rich gas, 2) a water-gas shift (WGS) reactor to convert CO to H2, and 3) a H2 separation membrane to separate only high-purity H2. Diesel and H2O2 can easily be pressurized as they are liquids. The application of the H2 separation membrane without a compressor in the middle of the process is thus advantageous. In this paper, the characteristics of pressurized ATR and WGS reactions are investigated according to the operating conditions. In both reactors, the methanation reaction is enhanced as the pressure increases. Then, permeation experiments with a H2 separation membrane are performed while varying the temperature, pressure difference, and inlet gas composition. In particular, approximately 90% of the H2 is recovered when the steam-separated rear gas of the WGS reactor is used in the H2 separation membrane. Finally, based on the experimental results, design points are suggested for maximizing the efficiency of the diesel-H2O2 fuel processor.

Superbase-derived protic ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

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.

A polymeric liquid membrane electrode responsive to 3,3',5,5'-tetramethylbenzidine oxidation for sensitive peroxidase/peroxidase mimetic-based potentiometric biosensing.

PubMed

Wang, Xuewei; Yang, Yangang; Li, Long; Sun, Mingshuang; Yin, Haogen; Qin, Wei

2014-05-06

The oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) has great utility in bioanalysis such as peroxidase/peroxidase mimetic-based biosensing. In this paper, the behaviors of TMB oxidation intermediates/products in liquid/liquid biphasic systems have been investigated for the first time. The free radical, charge transfer complex, and diimine species generated by TMB oxidation are all positively charged under acidic and near-neutral conditions. Electron paramagnetic resonance and visible absorbance spectroscopy data demonstrate that these cationic species can be effectively transferred from an aqueous phase into a water-immiscible liquid phase functionalized by an appropriate cation exchanger. Accordingly, sensitive potential responses of TMB oxidation have been obtained on a cation exchanger-doped polymeric liquid membrane electrode under mildly acidic and near-neutral conditions. By using the membrane electrode responsive to TMB oxidations, two sensitive potentiometric biosensing schemes including the peroxidase-labeled sandwich immunoassay and G-quadruplex DNAzyme-based DNA hybridization assay have been developed. The obtained detection limits for the target antigen and DNA are 0.02 ng/mL and 0.1 nM, respectively. Coupled with other advantages such as low cost, high reliability, and ease of miniaturization and integration, the proposed polymeric liquid membrane electrode holds great promise as a facile and efficient transducer for TMB oxidation and related biosensing applications.

High Performance Platinum Group Metal Free Membrane Electrode Assemblies through Control of Interfacial Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayers, Katherine; Capuano, Christopher; Atanassov, Plamen

The quantitative goal of this project was to produce a high-performance anion exchange membrane water electrolyzer (AEM-WE) completely free of platinum group metals (PGMs), which could operate for at least 500 hours with less than 50 microV/hour degradation, at 500 mA/cm 2. To achieve this goal, work focused on the optimization of electrocatalyst conductivity, with dispersion and utilization in the membrane electrode assembly (MEA) improved through refinement of deposition techniques. Critical factors were also explored with significant work undertaken by Northeastern University to further understand catalyst-membrane-ionomer interfaces and how they differ from liquid electrolyte. Water management and optimal cell operationalmore » parameters were established through the design, fabrication, and test of a new test station at Proton specific for AEM evaluation. Additionally, AEM material stability and robustness at high potentials and gas evolution conditions were advanced at Penn State.« less

Claisen thermally rearranged (CTR) polymers

PubMed Central

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-01-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

Claisen thermally rearranged (CTR) polymers.

PubMed

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-07-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

Denitrification of drinking water in a two-stage membrane bioreactor by using immobilized biomass.

PubMed

Ravnjak, Matjaž; Vrtovšek, Janez; Pintar, Albin

2013-01-01

Nitrate removal from polluted groundwater was investigated in a two-stage anoxic/oxic biofilm membrane bioreactor. The process was carried out with ethanol as a carbon source (corresponding C/N ratio of 1.4-2.5) and commercially available Biocontact-N biocarriers (Nisshinbo, Japan) to enable immobilization of highly efficient and long-lasting microbiota. At a residence time of the liquid phase equal to 2.5h, nitrate conversions higher than 99% were obtained without the formation of nitrite and ammonium ions. The concentration of total organic carbon in the reactor discharge was very similar to the content of organic matter in tap water. The biocarriers minimized the occurrence of suspended filamentous bacteria, and the utilization of increased shear force facilitated collisions of floating biocarrier particles with the outer membrane surface, preventing membrane fouling and resulting in stable operation of the system for 40 days. Copyright © 2012 Elsevier Ltd. All rights reserved.

Methods for forming small-volume electrical contacts and material manipulations with fluid microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-12-27

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-04-26

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microehannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C [Knoxville, TN; Ramsey, J Michael [Knoxville, TN; Culbertson, Christopher T [Oak Ridge, TN; Whitten, William B [Lancing, TN; Foote, Robert S [Oak Ridge, TN

2011-03-22

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael

2007-11-20

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Methods for forming small-volume electrical contacts and material manipulations with fluidic microchannels

DOEpatents

Jacobson, Stephen C.; Ramsey, J. Michael; Culbertson, Christopher T.; Whitten, William B.; Foote, Robert S.

2004-02-03

A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Single-ion polymer electrolyte membranes enable lithium-ion batteries with a broad operating temperature range.

PubMed

Cai, Weiwei; Zhang, Yunfeng; Li, Jing; Sun, Yubao; Cheng, Hansong

2014-04-01

Conductive processes involving lithium ions are analyzed in detail from a mechanistic perspective, and demonstrate that single ion polymeric electrolyte (SIPE) membranes can be used in lithium-ion batteries with a wide operating temperature range (25-80 °C) through systematic optimization of electrodes and electrode/electrolyte interfaces, in sharp contrast to other batteries equipped with SIPE membranes that display appreciable operability only at elevated temperatures (>60 °C). The performance is comparable to that of batteries using liquid electrolyte of inorganic salt, and the batteries exhibit excellent cycle life and rate performance. This significant widening of battery operation temperatures coupled with the inherent flexibility and robustness of the SIPE membranes makes it possible to develop thin and flexible Li-ion batteries for a broad range of applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Porous micropillar structures for retaining low surface tension liquids.

PubMed

Agonafer, Damena D; Lee, Hyoungsoon; Vasquez, Pablo A; Won, Yoonjin; Jung, Ki Wook; Lingamneni, Srilakshmi; Ma, Binjian; Shan, Li; Shuai, Shuai; Du, Zichen; Maitra, Tanmoy; Palko, James W; Goodson, Kenneth E

2018-03-15

The ability to manipulate fluid interfaces, e.g., to retain liquid behind or within porous structures, can be beneficial in multiple applications, including microfluidics, biochemical analysis, and the thermal management of electronic systems. While there are a variety of strategies for controlling the disposition of liquid water via capillarity, such as the use of chemically modified porous adhesive structures and capillary stop valves or surface geometric features, methods that work well for low surface tension liquids are far more difficult to implement. This study demonstrates the microfabrication of a silicon membrane that can retain exceptionally low surface tension fluorinated liquids against a significant pressure difference across the membrane via an array of porous micropillar structures. The membrane uses capillary forces along the triple phase contact line to maintain stable liquid menisci that yield positive working Laplace pressures. The micropillars have inner diameters and thicknesses of 1.5-3 μm and ∼1 μm, respectively, sustaining Laplace pressures up to 39 kPa for water and 9 kPa for Fluorinert™ (FC-40). A theoretical model for predicting the change in pressure as the liquid advances along the porous micropillar structure is derived based on a free energy analysis of the liquid meniscus with capped spherical geometry. The theoretical prediction was found to overestimate the burst pressure compared with the experimental measurements. To elucidate this deviation, transient numerical simulations based on the Volume of Fluid (VOF) were performed to explore the liquid pressure and evolution of meniscus shape under different flow rates (i.e., Capillary numbers). The results from VOF simulations reveal strong dynamic effects where the anisotropic expansion of liquid along the outer micropillar edge leads to an irregular meniscus shape before the liquid spills along the micropillar edge. These findings suggest that the analytical prediction of burst Laplace pressure obtained under quasi-static condition (i.e., equilibrium thermodynamic analysis under low capillary number) is not applicable to highly dynamic flow conditions, where the liquid meniscus shape deformation by flow perturbation cannot be restored by surface tension force instantaneously. Therefore, the critical burst pressure is dependent on the liquid velocity and viscosity under dynamic flow conditions. A numerical simulation using Surface Evolver also predicts that surface defects along the outer micropillar edge can yield up to 50% lower Laplace pressures than those predicted with ideal feature geometries. The liquid retention strategy developed here can facilitate the routing and phase management of dielectric working fluids for application in heat exchangers. Further improvements in the retention performance can be realized by optimizing the fabrication process to reduce surface defects. Copyright © 2017 Elsevier Inc. All rights reserved.

An Ionic Liquid Reaction and Separation Process for Production of Hydroxymethylfurfural from Sugars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wei; Zheng, Feng; Li, Joanne

2014-01-01

There has been world-wide interest to making plastics out of renewable biomass feedstock for recent years. Hydroxymethylfurfural (HMF) is viewed as an attractive alternate to terephthalic acid (TPA) for production of polyesters (PET) and polyamides. Conversion of sugars into HMF has been studied in numerous publications. In this work, a complete ionic liquid reaction and separation process is presented for nearly stoichiometric conversion of fructose into HMF. Different adsorbent materials are evaluated and silicalite material is demonstrated effective for isolation of 99% pure HMF from actual ionic liquid reaction mixtures and for recovery of the un-converted sugars and reaction intermediatemore » along with the ionic liquid. Membrane-coated silicalite particles are prepared and studied for a practical adsorption process operated at low pressure drops but with separation performances comparable or better than the powder material. Complete conversion of fresh fructose feed into HMF in the recycled ionic liquid is shown under suitable reaction conditions. Stability of HMF product is characterized. A simplified process flow diagram is proposed based on these research results, and the key equipment such as reactor and adsorbent bed is sized for a plant of 200,000 ton/year of fructose processing capacity. The proposed HMF production process is much simpler than the current paraxylene (PX) manufacturing process from petroleum oil, which suggests substantial reduction to the capital cost and energy consumption be possible. At the equivalent value to PX on the molar basis, there can be a large gross margin for HMF production from fructose and/or sugars.« less

NafionxAE-based polymer actuators with ionic liquids as solvent incorporated at room temperature

NASA Astrophysics Data System (ADS)

Kikuchi, Kunitomo; Tsuchitani, Shigeki

2009-09-01

Nafion®-based ionic polymer-metal composites (IPMCs), with ionic liquids as solvent, were fabricated by exchanging counterions to ionic liquids at room temperature. Ion exchange is performed by only immersing IPMC in a mixture of de-ionized water and ionic liquids at room temperature for 48 h. The fabricated IPMCs exhibited a bending curvature the same as or larger than that of conventional IPMCs with ionic liquids, formed by ion exchange to ionic liquids at an elevated temperature up to about 100 °C, and also had long-term stability in operation in air, with a fluctuation smaller than 21% in bending curvature during a 180 min operation. The effective ion exchange to ionic liquids in the present method is probably due to an increase in diffusion speed of ionic liquids into IPMC by adsorption of water in a Nafion® membrane. It is a surprise that among IPMCs with ionic liquids 1-ethyl-3-methyl-imidazolium tetrafluoroborate, 1-buthyl-3-methyl-imidazolium tetrafluoroborate (BMIBF4), and 1-buthyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6), IPMC with water-insoluble BMIPF6 exhibited a larger bending curvature than that IPMC with water-miscible BMIBF4. This might be due to effective incorporation of BMIPF6 into IPMC, since BMIPF6 has a higher affinity with IPMC than with water in the mixture of water and BMIPF6. From measurements of complex impedance and step voltage response of the driving current of IPMCs with ionic liquid, they are expressed by an equivalent circuit of a parallel combination of a serial circuit of membrane resistance of Nafion® and electric double layer capacitance at metal electrodes, with membrane capacitance of Nafion®, in a frequency range higher than about 0.1 Hz. The difference in magnitude of bending curvature in three kinds of IPMCs with ionic liquids is mainly due to the difference in bending response speed coming from the difference in the membrane resistance.

Long Duration Testing of a Spacesuit Water Membrane Evaporator Prototype

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Makinen, Janice; Cox, Marlon; Watts, Carly; Campbell, Colin; Vogel, Matthew; Colunga, Aaron

2011-01-01

The Spacesuit Water Membrane Evaporator (SWME) is a heat-rejection device that is being developed to perform thermal control for advanced spacesuits. Cooling is achieved by circulating water from the liquid cooling garment (LCG) through hollow fibers (HoFi?s), which are small hydrophobic tubes. Liquid water remains within the hydrophobic tubes, but water vapor is exhausted to space, thereby removing heat. A SWME test article was tested over the course of a year, for a total of 1200 cumulative hours. In order to evaluate SWME tolerance to contamination due to constituents caused by distillation processes, these constituents were allowed to accumulate in the water as evaporation occurred. A test article was tested over the course of a year for a total of 1200 cumulative hours. The heat rejection performance of the SWME degraded significantly--below 700 W, attributable to the accumulation of rust in the circulating loop and biofilm growth. Bubble elimination capability, a feature that was previously proven with SWME, was compromised during the test, most likely due to loss of hydrophobic properties of the hollow fibers. The utilization of water for heat rejection was shown not to be dependent on test article, life cycle, heat rejection rate, or freezing of the membranes.

Application of edible paraffin oil for cationic dye removal from water using emulsion liquid membrane.

PubMed

Zereshki, Sina; Daraei, Parisa; Shokri, Amin

2018-05-18

Using an emulsion liquid membrane based on edible oils is investigated for removing cationic dyes from aqueous solutions. There is a great potential for using edible oils in food industry extraction processes. The parameters affecting the stability of the emulsion and the extraction rate were studied. These parameters were the emulsification time, the stirring speed, the surfactant concentration, the internal phase concentration, the feed phase concentration, the volume ratio of internal phase to organic phase and the treat ratio. In order to stabilize the emulsion without using a carrier, edible paraffin oil and heptane are used at an 80:20 ratio. The optimum conditions for the extraction of methylene blue (MB), crystal violet and methyl violet (CV and MV) cationic dyes using edible paraffin oil as an environment friendly solvent are represented. A removal percentage of 95% was achieved for a mixture of dyes. The optimum concentration of sodium hydroxide in the internal phase, which results a stabile emulsion with a high stripping efficiency of 96%, was 0.04 M. An excellent membrane recovery was observed and the extraction of dyes did not decrease up to seven run cycles. Copyright © 2018 Elsevier B.V. All rights reserved.

Long Duration Testing of a Spacesuit Water Membrane Evaporator Prototype

NASA Technical Reports Server (NTRS)

Bue, Grant C.; Makinen, Janice; Cox, Marlon; Watts, Carly; Campbell, Colin; Vogel, Matthew; Colunga, Aaron; Conger, Bruce

2012-01-01

The Spacesuit Water Membrane Evaporator (SWME) is a heat-rejection device that is being developed to perform thermal control for advanced spacesuits. Cooling is achieved by circulating water from the liquid cooling garment (LCG) through hollow fibers (HoFi s), which are small hydrophobic tubes. Liquid water remains within the hydrophobic tubes, but water vapor is exhausted to space, thereby removing heat. A SWME test article was tested over the course of a year, for a total of 600 cumulative hours. In order to evaluate SWME tolerance to contamination due to constituents caused by distillation processes, these constituents were allowed to accumulate in the water as evaporation occurred. A test article was tested over the course of a year for a total of 600 cumulative hours. The heat rejection performance of the SWME degraded significantly--below 700 W, attributable to the accumulation of rust in the circulating loop and biofilm growth. Bubble elimination capability, a feature that was previously proven with SWME, was compromised during the test, most likely due to loss of hydrophobic properties of the hollow fibers. The utilization of water for heat rejection was shown not to be dependent on test article, life cycle, heat rejection rate, or freezing of the membranes.

Tracking oil and gas wastewater-derived organic matter in a hybrid biofilter membrane treatment system: A multi-analytical approach.

PubMed

Riley, Stephanie M; Ahoor, Danika C; Regnery, Julia; Cath, Tzahi Y

2018-02-01

Dissolved organic matter (DOM) present in oil and gas (O&G) produced water and fracturing flowback was characterized and quantified by multiple analytical techniques throughout a hybrid biological-physical treatment process. Quantitative and qualitative analysis of DOM by liquid chromatography - organic carbon detection (LC-OCD), liquid chromatography-high-resolution mass spectrometry (LC-HRMS), gas chromatography-mass spectrometry (GC-MS), and 3D fluorescence spectroscopy, demonstrated increasing removal of all groups of DOM throughout the treatment train, with most removal occurring during biological pretreatment and some subsequent removal achieved during membrane treatment. Parallel factor analysis (PARAFAC) further validated these results and identified five fluorescent components, including DOM described as humic acids, fulvic acids, proteins, and aromatics. Tryptophan-like compounds bound by complexation to humics/fulvics were most difficult to remove biologically, while aromatics (particularly low molecular weight neutrals) were more challenging to remove with membranes. Strong correlation among PARAFAC, LC-OCD, LC-HRMS, and GC-MS suggests that PARAFAC can be a quick, affordable, and accurate tool for evaluating the presence or removal of specific DOM groups in O&G wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrodynamic interactions in freely suspended liquid crystal films

NASA Astrophysics Data System (ADS)

Kuriabova, Tatiana; Powers, Thomas R.; Qi, Zhiyuan; Goldfain, Aaron; Park, Cheol Soo; Glaser, Matthew A.; Maclennan, Joseph E.; Clark, Noel A.

2016-11-01

Hydrodynamic interactions play an important role in biological processes in cellular membranes, a large separation of length scales often allowing such membranes to be treated as continuous, two-dimensional (2D) fluids. We study experimentally and theoretically the hydrodynamic interaction of pairs of inclusions in two-dimensional, fluid smectic liquid crystal films suspended in air. Such smectic membranes are ideal systems for performing controlled experiments as they are mechanically stable, of highly uniform structure, and have well-defined, variable thickness, enabling experimental investigation of the crossover from 2D to 3D hydrodynamics. Our theoretical model generalizes the Levine-MacKintosh theory of point-force response functions and uses a boundary-element approach to calculate the mobility matrix for inclusions of finite extent. We describe in detail the theoretical and computational approach previously outlined in Z. Qi et al., Phys. Rev. Lett. 113, 128304 (2014), 10.1103/PhysRevLett.113.128304 and extend the method to study the mutual mobilities of inclusions with asymmetric shapes. The model predicts well the observed mutual mobilities of pairs of circular inclusions in films and the self-mobility of a circular inclusion in the vicinity of a linear boundary.

Energy efficient of ethanol recovery in pervaporation membrane bioreactor with mechanical vapor compression eliminating the cold traps.

PubMed

Fan, Senqing; Xiao, Zeyi; Li, Minghai

2016-07-01

An energy efficient pervaporation membrane bioreactor with mechanical vapor compression was developed for ethanol recovery during the process of fermentation coupled with pervaporation. Part of the permeate vapor at the membrane downstream under the vacuum condition was condensed by running water at the first condenser and the non-condensed vapor enriched with ethanol was compressed to the atmospheric pressure and pumped into the second condenser, where the vapor was easily condensed into a liquid by air. Three runs of fermentation-pervaporation experiment have been carried out lasting for 192h, 264h and 360h respectively. Complete vapor recovery validated the novel pervaporation membrane bioreactor. The total flux of the polydimethylsiloxane (PDMS) membrane was in the range of 350gm(-2)h(-1) and 600gm(-2)h(-1). Compared with the traditional cold traps condensation, mechanical vapor compression behaved a dominant energy saving feature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Membrane contactors in the beverage industry for controlling the water gas composition.

PubMed

Criscuoli, Alessandra; Drioli, Enrico; Moretti, Ugo

2003-03-01

In the work described here, membrane contactors are used for coupling the removal of species (oxygen and hydrogen sulfide) present in the water with the water carbonation process. We include both experiments and a theoretical study devoted to the analysis of the transport phenomena that occur in the membrane contactor. The main resistance to mass transport was located at the liquid side. Correlations between Sherwood and Reynolds numbers on the shell side that are suitable for the membrane contactor used to carry out our experiments have been determined. In particular, for Re > 1.6, the expression proposed by Yang and Cussler in 1986: Sh = 0.90 Re(0.40) Sc(0.33) describes the behavior of the system; whereas, for Re between 0.03 and 0.3, a new expression is proposed: Sh = 0.435 Re(1.2)Sc(0.33). A comparison with traditional equipment is also furnished. Membrane contactors offer reduced size, CO(2) consumption, and capital costs.

The critical pressure drop for the purge process in the anode of a fuel cell

NASA Astrophysics Data System (ADS)

Yu, Xiao; Pingwen, Ming; Ming, Hou; Baolian, Yi; Shao, Zhi-Gang

Purge operation is an effective way to remove the accumulated liquid water in the anode of proton exchange membrane fuel cells (PEMFCs). This paper studies the phenomenon of the two-phase flow as well as the pressure drop fluctuation inside the flow field of a single cell during the purge process. The flow patterns are identified as intermittent purge and annular purge, and the two purge processes are contrastively analyzed and discussed. The intermittent purge greatly affects the fuel cell performance and thus it is not suitable for the in situ application. The annular purge process requires a higher pressure drop, and the critical pressure drop is calculated from the annular purge model. Furthermore, this value is quantitatively analyzed and validated by experiments. The results show that the annular purge is appropriate for removing liquid water out of the anode in the fuel cell.

Development of Omniphobic Desalination Membranes Using a Charged Electrospun Nanofiber Scaffold.

PubMed

Lee, Jongho; Boo, Chanhee; Ryu, Won-Hee; Taylor, André D; Elimelech, Menachem

2016-05-04

In this study, we present a facile and scalable approach to fabricate omniphobic nanofiber membranes by constructing multilevel re-entrant structures with low surface energy. We first prepared positively charged nanofiber mats by electrospinning a blend polymer-surfactant solution of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cationic surfactant (benzyltriethylammonium). Negatively charged silica nanoparticles (SiNPs) were grafted on the positively charged electrospun nanofibers via dip-coating to achieve multilevel re-entrant structures. Grafted SiNPs were then coated with fluoroalkylsilane to lower the surface energy of the membrane. The fabricated membrane showed excellent omniphobicity, as demonstrated by its wetting resistance to various low surface tension liquids, including ethanol with a surface tension of 22.1 mN/m. As a promising application, the prepared omniphobic membrane was tested in direct contact membrane distillation to extract water from highly saline feed solutions containing low surface tension substances, mimicking emerging industrial wastewaters (e.g., from shale gas production). While a control hydrophobic PVDF-HFP nanofiber membrane failed in the desalination/separation process due to low wetting resistance, our fabricated omniphobic membrane exhibited a stable desalination performance for 8 h of operation, successfully demonstrating clean water production from the low surface tension feedwater.

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.

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)

Soft x-ray spectroscopy of high pressure liquid.

PubMed

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

2018-01-01

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3 N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3 N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3 N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3 N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3 N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.

Soft x-ray spectroscopy of high pressure liquid

DOE PAGES

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; ...

2018-01-01

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Soft x-ray spectroscopy of high pressure liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

PubMed Central

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains. PMID:28045119

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

NASA Astrophysics Data System (ADS)

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains.

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-01-01

Gas-liquid interfacial atmospheric-pressure plasma jets (GLI-APPJ) are used medically for plasma-induced cell-membrane permeabilization. In an attempt to identify the dominant factors induced by GLI-APPJ responsible for enhancing cell-membrane permeability, the concentration and distribution of plasma-produced reactive species in the gas and liquid phase regions are measured. These reactive species are classified in terms of their life-span: long-lived (e.g., H 2 O 2 ), short-lived (e.g., O 2 •- ), and extremely-short-lived (e.g., • OH). The concentration of plasma-produced • OH aq in the liquid phase region decreases with an increase in solution thickness (<1 mm), and plasma-induced cell-membrane permeabilization is found to decay markedly as the thickness of the solution increases. Furthermore, the horizontally center-localized distribution of • OH aq , resulting from the center-peaked distribution of • OH in the gas phase region, corresponds with the distribution of the permeabilized cells upon APPJ irradiation, whereas the overall plasma-produced oxidizing species such as H 2 O 2aq in solution exhibit a doughnut-shaped horizontal distribution. These results suggest that • OH aq is likely one of the dominant factors responsible for plasma-induced cell-membrane permeabilization.

Interaction of saponin 1688 with phase separated lipid bilayers.

PubMed

Chen, Maohui; Balhara, Vinod; Jaimes Castillo, Ana Maria; Balsevich, John; Johnston, Linda J

2017-07-01

Saponins are a diverse family of naturally occurring plant triterpene or steroid glycosides that have a wide range of biological activities. They have been shown to permeabilize membranes and in some cases membrane disruption has been hypothesized to involve saponin/cholesterol complexes. We have examined the interaction of steroidal saponin 1688-1 with lipid membranes that contain cholesterol and have a mixture of liquid-ordered (L o ) and liquid-disordered (L d ) phases as a model for lipid rafts in cellular membranes. A combination of atomic force microscopy (AFM) and fluorescence was used to probe the effect of saponin on the bilayer. The results demonstrate that saponin forms defects in the membrane and also leads to formation of small aggregates on the membrane surface. Although most of the membrane damage occurs in the liquid-disordered phase, fluorescence results demonstrate that saponin localizes in both ordered and disordered membrane phases, with a modest preference for the disordered regions. Similar effects are observed for both direct incorporation of saponin in the lipid mixture used to make vesicles/bilayers and for incubation of saponin with preformed bilayers. The results suggest that the initial sites of interaction are at the interface between the domains and surrounding disordered phase. The preference for saponin localization in the disordered phase may reflect the ease of penetration of saponin into a less ordered membrane, rather than the actual cholesterol concentration in the membrane. Dye leakage assays indicate that a high concentration of saponin is required for membrane permeabilization consistent with the supported lipid bilayer experiments. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

PubMed

Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

2015-07-14

Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Mercury removal from aqueous streams utilizing microemulsion liquid membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1994-11-01

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

Boron removal in radioactive liquid waste by forward osmosis membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doo Seong Hwang; Hei Min Choi; Kune Woo Lee

2013-07-01

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

The effects of different levels of superoxide dismutase in Modena on boar semen quality during liquid preservation at 17°C.

PubMed

Zhang, Xiao-Gang; Li, Hao; Wang, Le; Hao, Yang-Yi; Liang, Guo-Dong; Ma, Yun-Hui; Yang, Gong-She; Hu, Jian-Hong

2017-01-01

This study was conducted to investigate the influence of superoxide dismutase (SOD) on the quality of boar semen during liquid preservation at 17°C. Semen samples from 10 Duroc boars were collected and pooled, divided into five equal parts and diluted with Modena containing different concentrations (0, 100, 200, 300 and 400 U/mL) of SOD. During the process of liquid preservation at 17°C, sperm motility, acrosome integrity, membrane integrity, total antioxidant capacity (T-AOC) activity, malondialdehyde (MDA) content and hydrogen peroxide (H 2 O 2 ) content were measured and analyzed every 24 h. Meanwhile, effective survival time of boar semen during preservation was evaluated and analyzed. The results indicated that different concentrations of SOD in Modena showed different protective effects on boar sperm quality. Modena supplemented with SOD decreased the effects on reactive oxygen species on boar sperm quality during liquid preservation compared with that of the control group. The added 200 U/mL SOD group showed higher sperm motility, membrane integrity, acrosome integrity, effective survival time and T-AOC activity. Meanwhile, the added 200 U/mL SOD group showed lower MDA content and H 2 O 2 content. In conclusion, addition of SOD to Modena improved the boar sperm quality by reducing oxidative stress during liquid preservation at 17°C and the optimum concentration was 200 U/mL. © 2016 Japanese Society of Animal Science.

Hyper-Cross-Linked Additives that Impede Aging and Enhance Permeability in Thin Polyacetylene Films for Organic Solvent Nanofiltration.

PubMed

Cheng, Xi Quan; Konstas, Kristina; Doherty, Cara M; Wood, Colin D; Mulet, Xavier; Xie, Zongli; Ng, Derrick; Hill, Matthew R; Shao, Lu; Lau, Cher Hon

2017-04-26

Membrane materials with high permeability to solvents while rejecting dissolved contaminants are crucial to lowering the energy costs associated with liquid separations. However, the current lack of stable high-permeability materials require innovative engineering solutions to yield high-performance, thin membranes using stable polymers with low permeabilities. Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) is one of the most permeable polymers but is extremely susceptible to physical aging. Despite recent developments in anti-aging polymer membranes, this research breakthrough has yet to be demonstrated on thin PTMSP films supported on porous polymer substrates, a crucial step toward commercializing anti-aging membranes for industrial applications. Here we report the development of scalable, thin film nanocomposite membranes supported on polymer substrates that are resistant to physical aging while having high permeabilities to alcohols. The selective layer is made up of PTMSP and nanoporous polymeric additives. The nanoporous additives provide additional passageways to solvents, enhancing the high permeability of the PTMSP materials further. Through intercalation of polyacetylene chains into the sub-nm pores of organic additives, physical aging in the consequent was significantly hindered in continuous long-term operation. Remarkably we also demonstrate that the additives enhance both membrane permeability and rejection of dissolved contaminants across the membranes, as ethanol permeability at 5.5 × 10 -6 L m m -2 h -1 bar -1 with 93% Rose Bengal (1017.6 g mol -1 ) rejection, drastically outperforming commercial and state-of-the-art membranes. These membranes can replace energy-intensive separation processes such as distillation, lowering operation costs in well-established pharmaceutical production processes.

Trace Metals Derived from Electronic Cigarette (ECIG) Generated Aerosol: Potential Problem of ECIG Devices That Contain Nickel

PubMed Central

Palazzolo, Dominic L.; Crow, Andrew P.; Nelson, John M.; Johnson, Robert A.

2017-01-01

Introduction: ECIGs are currently under scrutiny concerning their safety, particularly in reference to the impact ECIG liquids (E-liquids) have on human health. One concern is that aerosolized E-liquids contain trace metals that could become trapped in respiratory tissues and induce pathology. Methods: To mimic this trapping, peristaltic pumps were used to generate and transport aerosol onto mixed cellulose ester (MCE) membranes where aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) were subsequently captured and quantified. The presence of trace metals on unexposed MCE membranes and on MCE membranes exposed to mainstream smoke served as control and comparison, respectively. The presence of these metals was also determined from the E-liquid before aerosolization and untouched by the ECIG device. All metals were quantified using ICP-MS. The ECIG core assembly was analyzed using scanning electron microscopy with elemental analysis capability. Results: The contents (μg) of Al, As, Cd, Cu, Fe, Mn, Ni, Pb, and Zn on control MCE membranes were 1.2 ± 0.2, 0.050 ± 0.002, 0.047 ± 0.003, 0.05 ± 0.01, 0.001 ± 0.001, 0.16 ± 0.04, 0.005 ± 0.003, 0.014 ± 0.006, and 0.09 ± 0.02, respectively. The contents of all trace metals on MCE membranes exposed to aerosol were similar to controls, except Ni which was significantly (p < 0.01) higher (0.024 ± 0.004 μg). In contrast, contents of Al, As, Fe, Mn, and Zn on MCE membranes exposed to smoke were significantly higher (p < 0.05) than controls. The contents of Al, As, Cu, Fe, and Mn on smoke-exposed MCE membranes were also significantly higher (p < 0.05) than their content on aerosol-exposed membranes. The contents per cigarette equivalent of metals in E-liquid before aerosolization were negligible compared to amounts of aerosolized E-liquid, except for Fe (0.002 μg before and 0.001 μg after). Elemental analysis of the core assembly reveals the presence of several of these trace metals, especially Al, Fe, Ni, and Zn. Conclusions: In general, from the single ECIG-device/E-liquid combination used, the amount of trace metals from ECIG-generated aerosol are lower than in traditional mainstream smoke, Only Ni in the ECIG-generated aerosol was higher than control. The most probable source of Ni in this aerosol is the core assembly. PMID:28119618

Electron transparent graphene windows for environmental scanning electron microscopy in liquids and dense gases.

PubMed

Stoll, Joshua D; Kolmakov, Andrei

2012-12-21

Due to its ultrahigh electron transmissivity in a wide electron energy range, molecular impermeability, high electrical conductivity and excellent mechanical stiffness, suspended graphene membranes appear to be a nearly ideal window material for in situ (in vivo) environmental electron microscopy of nano- and mesoscopic objects (including bio-medical samples) immersed in liquids and/or in dense gaseous media. In this paper, taking advantage of a small modification of the graphene transfer protocol onto metallic and SiN supporting orifices, reusable environmental cells with exchangeable graphene windows have been designed. Using colloidal gold nanoparticles (50 nm) dispersed in water as model objects for scanning electron microscopy in liquids as proof of concept, different conditions for imaging through the graphene membrane were tested. Limiting factors for electron microscopy in liquids, such as electron beam induced water radiolysis and damage of the graphene membrane at high electron doses, are discussed.

Thermodynamics of interaction of ionic liquids with lipid monolayer.

PubMed

Bhattacharya, G; Mitra, S; Mandal, P; Dutta, S; Giri, R P; Ghosh, S K

2018-06-01

Understanding the interaction of ionic liquids with cellular membrane becomes utterly important to comprehend the activities of these liquids in living organisms. Lipid monolayer formed at the air-water interface is employed as a model system to follow this interaction by investigating important thermodynamic parameters. The penetration kinetics of the imidazolium-based ionic liquid 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4]) into the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid layer is found to follow the Boltzmann-like equation that reveals the characteristic time constant which is observed to be the function of initial surface pressure. The enthalpy and entropy calculated from temperature-dependent pressure-area isotherms of the monolayer show that the added ionic liquids bring about a disordering effect in the lipid film. The change in Gibbs free energy indicates that an ionic liquid with longer chain has a far greater disordering effect compared to an ionic liquid with shorter chain. The differential scanning calorimetric measurement on a multilamellar vesicle system shows the main phase transition temperature to shift to a lower value, which, again, indicates the disordering effect of the ionic liquid on lipid membrane. All these studies fundamentally point out that, when ionic liquids interact with lipid molecules, the self-assembled structure of a cellular membrane gets perturbed, which may be the mechanism of these molecules having adverse effects on living organisms.

Sub-micron particle sampler apparatus and method for sampling sub-micron particles

DOEpatents

Gay, D.D.; McMillan, W.G.

1984-04-12

Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however, the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis. 6 figures.

Sub-micron particle sampler apparatus

DOEpatents

Gay, Don D.; McMillan, William G.

1987-01-01

Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

Method for sampling sub-micron particles

DOEpatents

Gay, Don D.; McMillan, William G.

1985-01-01

Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s.

PubMed

Xu, Weinan; Ledin, Petr A; Shevchenko, Valery V; Tsukruk, Vladimir V

2015-06-17

Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes.

Liquid-liquid extraction and flat sheet supported liquid membrane studies on Am(III) and Eu(III) separation using 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine as the extractant.

PubMed

Bhattacharyya, A; Mohapatra, P K; Gadly, T; Raut, D R; Ghosh, S K; Manchanda, V K

2011-11-15

Solvent extraction and supported liquid membrane transport studies for the preferential removal of Am(3+) from feeds containing a mixture of Am(3+) and Eu(3+) was carried out using 2,6-bis(5,6-dipropyl-1,2,4-triazin-3-yl)pyridine (n-Pr-BTP) as the extractant. Diluent plays an important role in these studies. It was observed that the distribution coefficients deteriorate significantly for both Am(3+) and Eu(3+) though the separation factors were affected only marginally. The transport studies were carried out at pH 2.0 in the presence of NaNO(3) to result in the preferential Am(3+) transport with high separation factors. Effect of different experimental parameters, viz. feed composition, stripping agents, diluents of the organic liquid membrane and membrane pore size was studied on the transport and separation behaviour of Am(3+) and Eu(3+). The supported liquid membrane studies indicated about 85% Am(3+) and 6% Eu(3+) transport in 6h using 0.03 M n-Pr-BTP in n-dodecane/1-octanol (7:3) diluent mixture for a feed containing 1M NaNO(3) at pH 2 and a receiver phase containing pH 2 solution as the strippant. Consequently, a permeability coefficient of (1.75 ± 0.21) × 10(-4)cms(-1) was determined for the Am(3+) transport. Stability of the n-Pr-BTP and its SLM was also studied by carrying out the distribution and transport experiment after different time intervals. Copyright © 2011 Elsevier B.V. All rights reserved.

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.

Reliability of high-strain ionomeric polymer transducers fabricated using the novel direct assembly process

NASA Astrophysics Data System (ADS)

Akle, Barbar; Nawshin, Saila; Leo, Donald

2006-03-01

Ionomeric polymer transducers have received considerable attention in the past several years. These actuators, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. Typically, ionic polymer actuators are composed of Nafion-117 membranes with platinum electrodes and are saturated with water diluents. Recently the authors have developed a novel fabrication technique named the Direct Assembly Process (DAP), which allowed good control on electrode morphology and composition. The DAP consists of spraying two high surface area metal-ionomer electrodes on a Nafion membrane. A single- walled carbon nanotubes (SWNT) and ruthenium dioxide (RuO II) hybrid electrode was sprayed on a Formamide hydrated Nafion-117 membrane using the DAP method. This transducer was shown to generate 9.4% peak-peak strain under the application of +/-2V at a strain rate of 1%/sec. Furthermore using the DAP one is capable of incorporating several types of diluents in ionomeric polymer transducers. Transducers with ionic liquid diluents are demonstrated to operate in air for long periods of time. In this work we will present a reliability study of transducers fabricated using the DAP. Each transducer is tested under a frequency range of 0.2Hz to 1Hz, and a potential of +/-1V to +/-3V. Water hydrated transducers dehydrates and stop moving within 5 minutes while operating in air under +/-2V. Transducers with Formamide diluents operate for 20,000 cycles under +/-1.5V and 0.5Hz (around 11hrs), while they degrade in less than 3000 cycles under +/-2V and 0.5Hz. Ionic liquid based transducers are demonstrated to operate in air for over 400,000 with little loss in performance, and over 1 million cycle with a loss of only 43%. Actuators with several electrode compositions are fabricated and a correlation between the reliability of ionic liquid-ionic polymer transducers and maximum strain will be presented. This correlation will be used to assess the adhesion between the high surface area electrodes and the Nafion membrane. SEM images of tested transducers will be presented.

Effect of heat and radio frequency electric field treatments on membrane damage and intracellular leakage of UV-substances of Escherichia coli K-12 in apple juice

USDA-ARS?s Scientific Manuscript database

The need for a nonthermal intervention technology that can achieve microbial safety without altering nutritional quality of liquid foods led to the development of the radio frequency electric fields (RFEF) process. Previously, we documented formation of surface blebs on Escherichia coli cells treate...

DEMONSTRATION OF PILOT-SCALE PREVAPORATION SYSTEMS FOR VOLATILE ORGANIC COMPOUND REMOVAL FROM A SURFACTANT ENHANCED AQUIFER REMEDIATION FLUID. I. SPIRAL WOUND MEMBRANE MODULES

EPA Science Inventory

During the summer of 1996, a pilot-scale demonstration of a surfactant enhanced aquifer remediation (SEAR) process for removal of dense non-aqueous phase liquids (DNAPLs) from soils was conducted at Hill Air Force Base in Layton, Utah. Five thousand gallons of the extracted DNAP...

Monolithic Teflon membrane valves and pumps for harsh chemical and low-temperature use.

PubMed

Willis, Peter A; Hunt, Brian D; White, Victor E; Lee, Michael C; Ikeda, Michael; Bae, Sam; Pelletier, Michael J; Grunthaner, Frank J

2007-11-01

Microfluidic diaphragm valves and pumps capable of surviving conditions required for unmanned spaceflight applications have been developed. The Pasteur payload of the European ExoMars Rover is expected to experience temperatures ranging between -100 degrees C and +50 degrees C during its transit to Mars and on the Martian surface. As such, the Urey instrument package, which contains at its core a lab-on-a-chip capillary electrophoresis analysis system first demonstrated by Mathies et al., requires valving and pumping systems that are robust under these conditions before and after exposure to liquid samples, which are to be analyzed for chemical signatures of past or present living processes. The microfluidic system developed to meet this requirement uses membranes consisting of Teflon and Teflon AF as a deformable material in the valve seat region between etched Borofloat glass wafers. Pneumatic pressure and vacuum, delivered via off-chip solenoid valves, are used to actuate individual on-chip valves. Valve sealing properties of Teflon diaphragm valves, as well as pumping properties from collections of valves, are characterized. Secondary processing for embossing the membrane against the valve seats after fabrication is performed to optimize single valve sealing characteristics. A variety of different material solutions are found to produce robust devices. The optimal valve system utilizes a membrane of mechanically cut Teflon sandwiched between two thin spun films of Teflon AF-1600 as a composite "laminated" diaphragm. Pump rates up to 1600 nL s(-1) are achieved with pumps of this kind. These high pumping rates are possible because of the very fast response of the membranes to applied pressure, enabling extremely fast pump cycling with relatively small liquid volumes, compared to analogous diaphragm pumps. The developed technologies are robust over extremes of temperature cycling and are applicable in a wide range of chemical environments.

Effect of engineered environment on microbial community structure in biofilter and biofilm on reverse osmosis membrane.

PubMed

Jeong, Sanghyun; Cho, Kyungjin; Jeong, Dawoon; Lee, Seockheon; Leiknes, TorOve; Vigneswaran, Saravanamuthu; Bae, Hyokwan

2017-11-01

Four dual media filters (DMFs) were operated in a biofiltration mode with different engineered environments (DMF I and II: coagulation with/without acidification and DMF III and IV: without/with chlorination). Designed biofilm enrichment reactors (BERs) containing the removable reverse osmosis (RO) coupons, were connected at the end of the DMFs in parallel to analyze the biofilm on the RO membrane by DMF effluents. Filtration performances were evaluated in terms of dissolved organic carbon (DOC) and assimilable organic carbon (AOC). Organic foulants on the RO membrane were also quantified and fractionized. The bacterial community structures in liquid (seawater and effluent) and biofilm (DMF and RO) samples were analyzed using 454-pyrosequencing. The DMF IV fed with the chlorinated seawater demonstrated the highest reductions of DOC including LMW-N as well as AOC among the other DMFs. The DMF IV was also effective in reducing organic foulants on the RO membrane surface. The bacterial community structure was grouped according to the sample phase (i.e., liquid and biofilm samples), sampling location (i.e., DMF and RO samples), and chlorination (chlorinated and non-chlorinated samples). In particular, the biofilm community in the DMF IV differed from the other DMF treatments, suggesting that chlorination exerted as stronger selective pressure than pH adjustment or coagulation on the biofilm community. In the DMF IV, several chemoorganotrophic chlorine-resistant biofilm-forming bacteria such as Hyphomonas, Erythrobacter, and Sphingomonas were predominant, and they may enhance organic carbon degradation efficiency. Diverse halophilic or halotolerant organic degraders were also found in other DMFs (i.e., DMF I, II, and III). Various kinds of dominant biofilm-forming bacteria were also investigated in RO membrane samples; the results provided possible candidates that cause biofouling when DMF process is applied as the pretreatment option for the RO process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solid/liquid extraction equilibria of phenolic compounds with trioctylphosphine oxide impregnated in polymeric membranes.

PubMed

Praveen, Prashant; Loh, Kai-Chee

2016-06-01

Trioctylphosphine oxide based extractant impregnated membranes (EIM) were used for extraction of phenol and its methyl, hydroxyl and chloride substituted derivatives. The distribution coefficients of the phenols varied from 2 to 234, in the order of 1-napthol > p-chlorophenol > m-cresol > p-cresol > o-cresol > phenol > catechol > pyrogallol > hydroquinone, when initial phenols loadings was varied in 100-2000 mg/L. An extraction model, based on the law of mass action, was formulated to predict the equilibrium distribution of the phenols. The model was in excellent agreement (R(2) > 0.97) with the experimental results at low phenols concentrations (<800 mg/L). At higher phenols loadings though, Langmuir isotherm was better suited for equilibrium prediction (R(2) > 0.95), which signified high mass transfer resistance in the EIMs. Examination of the effects of ring substitution on equilibrium, and bivariate statistical analysis between the amounts of phenols extracted into the EIMs and factors affecting phenols interaction with TOPO, indicated the dominant role of hydrophobicity in equilibrium determination. These results improve understanding of the solid/liquid equilibrium process between phenols and the EIMs, and these will be useful in designing phenol recovery process from wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins

PubMed Central

Hu, Shun-Wei; Chen, Shushi

2017-01-01

The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption. PMID:28398252

Large-Scale Membrane- and Lignin-Modified Adsorbent-Assisted Extraction and Preconcentration of Triazine Analogs and Aflatoxins.

PubMed

Hu, Shun-Wei; Chen, Shushi

2017-04-11

The large-scale simultaneous extraction and concentration of aqueous solutions of triazine analogs, and aflatoxins, through a hydrocarbon-based membrane (e.g., polyethylene, polyethylene/polypropylene copolymer) under ambient temperature and atmospheric pressure is reported. The subsequent adsorption of analyte in the extraction chamber over the lignin-modified silica gel facilitates the process by reducing the operating time. The maximum adsorption capacity values for triazine analogs and aflatoxins are mainly adsorption mechanism-dependent and were calculated to be 0.432 and 0.297 mg/10 mg, respectively. The permeation, and therefore the percentage of analyte extracted, ranges from 1% to almost 100%, and varies among the solvents examined. It is considered to be vapor pressure- and chemical polarity-dependent, and is thus highly affected by the nature and thickness of the membrane, the discrepancy in the solubility values of the analyte between the two liquid phases, and the amount of adsorbent used in the process. A dependence on the size of the analyte was observed in the adsorption capacity measurement, but not in the extraction process. The theoretical interaction simulation and FTIR data show that the planar aflatoxin molecule releases much more energy when facing toward the membrane molecule when approaching it, and the mechanism leading to the adsorption.

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.

Use of inhibitory solvents in multi-membrane bioreactor

NASA Technical Reports Server (NTRS)

Shuler, Michael L. (Inventor); Cho, Toohyon (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.

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.

Liquid hydrogen production via hydrogen sulfide methane reformation

NASA Astrophysics Data System (ADS)

Huang, Cunping; T-Raissi, Ali

Hydrogen sulfide (H 2S) methane (CH 4) reformation (H 2SMR) (2H 2S + CH 4 = CS 2 + 4H 2) is a potentially viable process for the removal of H 2S from sour natural gas resources or other methane containing gases. Unlike steam methane reformation that generates carbon dioxide as a by-product, H 2SMR produces carbon disulfide (CS 2), a liquid under ambient temperature and pressure-a commodity chemical that is also a feedstock for the synthesis of sulfuric acid. Pinch point analyses for H 2SMR were conducted to determine the reaction conditions necessary for no carbon lay down to occur. Calculations showed that to prevent solid carbon formation, low inlet CH 4 to H 2S ratios are needed. In this paper, we analyze H 2SMR with either a cryogenic process or a membrane separation operation for production of either liquid or gaseous hydrogen. Of the three H 2SMR hydrogen production flowsheets analyzed, direct liquid hydrogen generation has higher first and second law efficiencies of exceeding 80% and 50%, respectively.

Method for low temperature catalytic production of hydrogen

DOEpatents

Mahajan, Devinder

2003-07-22

The invention provides a process for the catalytic production of a hydrogen feed by exposing a hydrogen feed to a catalyst which promotes a base-catalyzed water-gas-shift reaction in a liquid phase. The hydrogen feed can be provided by any process known in the art of making hydrogen gas. It is preferably provided by a process that can produce a hydrogen feed for use in proton exchange membrane fuel cells. The step of exposing the hydrogen feed takes place preferably from about 80.degree. C. to about 150.degree. C.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Optimization of methylene blue removal by stable emulsified liquid membrane using Plackett–Burman and Box–Behnken designs of experiments

PubMed Central

Djenouhat, Meriem; Bendebane, Farida; Bahloul, Lynda; Samar, Mohamed E. H.

2018-01-01

The stability of an emulsified liquid membrane composed of Span80 as a surfactant, D2EHPA as an extractant and sulfuric acid as an internal phase was first studied according to different diluents and many operating parameters using the Plackett–Burman design of experiments. Then the removal of methylene blue from an aqueous solution has been carried out using this emulsified liquid membrane at its stability conditions. The effects of operating parameters were analysed from the Box–Behnken design of experiments. The optimization of the extraction has been realized applying the response surface methodology and the results showed that the dye extraction yielding 98.72% was achieved at optimized conditions. PMID:29515841

Acid extraction by supported liquid membranes containing basic carriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danesi, P.R.; Cianetti, C.; Horwitz, E.P.

1983-01-01

The extraction of HNO/sub 3/ (nitric acid) from aqueous solutions by permeation through a number of supported liquid membranes containing basic carriers dissolved in diethylbenzene has been studied. The results have shown that the best permeations are obtained with long chain aliphatic amines (TLA, Primene JM-T) followed by TOPO (trioctylphosphine oxide) and then by other monofunctional and bifunctional organophosphorous basic carriers. The influence of an aliphatic diluent on the permeability of HNO/sub 3/ through a supported liquid membrane containing TLA as carrier was also investigated. In this case the permeability to HNO/sub 3/ decreases as a result of the lowermore » diffusion coefficient of the acid-carrier complex in the more vicous aliphatic solvent. 4 figures.« less

Biomimetic membranes and methods of making biomimetic membranes

DOEpatents

Rempe, Susan; Brinker, Jeffrey C.; Rogers, David Michael; Jiang, Ying-Bing; Yang, Shaorong

2016-11-08

The present disclosure is directed to biomimetic membranes and methods of manufacturing such membranes that include structural features that mimic the structures of cellular membrane channels and produce membrane designs capable of high selectivity and high permeability or adsorptivity. The membrane structure, material and chemistry can be selected to perform liquid separations, gas separation and capture, ion transport and adsorption for a variety of applications.

A review of water recovery by vapour permeation through membranes.

PubMed

Bolto, Brian; Hoang, Manh; Xie, Zongli

2012-02-01

In vapour permeation the feed is a vapour, not a liquid as in pervaporation. The process employs a polymeric membrane as a semi-permeable barrier between the feed side under high pressure and the permeate side under low pressure. Separation is achieved by the different degrees to which components are dissolved in and diffuse through the membrane, the system working according to a solution-diffusion mechanism. The materials used in the membrane depend upon the types of compounds being separated, so water transport is favoured by hydrophilic material, whether organic or inorganic. The process is used for the dehydration of natural gas and various organic solvents, notably alcohol as biofuel, as well as the removal of water from air and its recovery from waste steam. Waste steam can be found in almost every plant/factory where steam is used. It is frequently contaminated and cannot be reused. Discharging the spent steam to the atmosphere is a serious energy loss and environmental issue. Recycling the steam can significantly improve the overall energy efficiency of an industry, which is responsible for massive CO(2) emissions. Steam separation at high fluxes and temperatures has been accomplished with a composite poly(vinyl alcohol) membrane containing silica nanoparticles, and also, less efficiently, with an inorganic zeolite membrane. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Conformal Membrane Reflectors for Deployable Optics

NASA Technical Reports Server (NTRS)

Hood, Patrick J.; Keys, Andrew S. (Technical Monitor)

2002-01-01

This presentation reports the Phase I results on NASA's Gossamer Spacecraft Exploratory Research and Technology Program. Cornerstone Research Group, Inc., the University of Rochester, and International Photonics Consultants collaborated to investigate the feasibility of free-standing, liquid-crystal-polymer (LCP) reflectors for integration into space-based optical systems. The goal of the program was to achieve large-diameter, broadband. reflective membranes that are resistant to the effects of space, specifically cryogenic environments and gamma-ray irradiation. Additionally, we assessed the applicability of utilizing the technology as tight sails, since, by their very nature, these films offer high-reflectivity at specified wavelengths. Previous research programs have demonstrated all-polymer, narrow-band Specular reflectors and diffuse membrane reflectors. The feasibility of fabricating an all-polymer broadband specular reflector and a narrow-band specular membrane reflector was assessed in the Phase I Gossamer program. In addition, preliminary gamma irradiation studies were conducted to determine the stability of the polymer reflectors to radiation. Materials and process technology were developed to fabricate coupon-scale reflectors of both broad- and narrow-band specular reflectors in Phase 1. This presentation will report the results of these studies, including, the performance of a narrow-band specular membrane. Gamma irradiation exposures indicate limited impact on the optical performance although additional exposure studies are warranted. Plans to scale up the membrane fabrication process will be presented.

Raft membrane domains: from a liquid-ordered membrane phase to a site of pathogen attack.

PubMed

van der Goot, F G; Harder, T

2001-04-01

While the existence of cholesterol/sphingolipid (raft) membrane domains in the plasma membrane is now supported by strong experimental evidence, the structure of these domains, their size, their dynamics, and their molecular composition remain to be understood. Raft domains are thought to represent a specific physical state of lipid bilayers, the liquid-ordered phase. Recent observations suggest that in the mammalian plasma membrane small raft domains in ordered lipid phases are in a dynamic equilibrium with a less ordered membrane environment. Rafts may be enlarged and/or stabilized by protein-mediated cross-linking of raft-associated components. These changes of plasma membrane structure are perceived by the cells as signals, most likely an important element of immunoreceptor signalling. Pathogens abuse raft domains on the host cell plasma membrane as concentration devices, as signalling platforms and/or entry sites into the cell. Elucidation of these interactions requires a detailed understanding raft structure and dynamics. Copyright 2001 Academic Press.

Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids.

PubMed

Gumí-Audenis, Berta; Costa, Luca; Carlá, Francesco; Comin, Fabio; Sanz, Fausto; Giannotti, Marina I

2016-12-19

Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information.

Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids

PubMed Central

Gumí-Audenis, Berta; Costa, Luca; Carlá, Francesco; Comin, Fabio; Sanz, Fausto; Giannotti, Marina I.

2016-01-01

Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information. PMID:27999368

Treatment of oil sands process-affected water (OSPW) using a membrane bioreactor with a submerged flat-sheet ceramic microfiltration membrane.

PubMed

Xue, Jinkai; Zhang, Yanyan; Liu, Yang; Gamal El-Din, Mohamed

2016-01-01

The release of oil sands process-affected water (OSPW) into the environment is a concern because it contains persistent organic pollutants that are toxic to aquatic life. A modified Ludzack-Ettinger membrane bioreactor (MLE-MBR) with a submerged ceramic membrane was continuously operated for 425 days to evaluate its feasibility on OSPW treatment. A stabilized biomass concentration of 3730 mg mixed liquor volatile suspended solids per litre and a naphthenic acid (NA) removal of 24.7% were observed in the reactor after 361 days of operation. Ultra Performance Liquid Chromatography/High Resolution Mass Spectrometry analysis revealed that the removal of individual NA species declined with increased ring numbers. Pyrosequencing analysis revealed that Betaproteobacteria were dominant in sludge samples from the MLE-MBR, with microorganisms such as Rhodocyclales and Sphingobacteriales capable of degrading hydrocarbon and aromatic compounds. During 425 days of continuous operation, no severe membrane fouling was observed as the transmembrane pressure (TMP) of the MLE-MBR never exceeded -20 kPa given that the manufacturer's suggested critical TMP for chemical cleaning is -35 kPa. Our results indicated that the proposed MLE-MBR has a good potential for removing recalcitrant organics in OSPW. Copyright © 2015 Elsevier Ltd. All rights reserved.

The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors.

PubMed

Tirunehe, Gossaye; Norddahl, B

2016-04-01

Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air-water and air-CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas-liquid mediums. CMC solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas-liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (U(G)) range of 0.0004-0.0025 m/s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (K(L)a) by a factor of 1.2-1.9 compared to the flat sheet membrane.

Membrane Bending Moduli of Coexisting Liquid Phases Containing Transmembrane Peptide.

PubMed

Usery, Rebecca D; Enoki, Thais A; Wickramasinghe, Sanjula P; Nguyen, V P; Ackerman, David G; Greathouse, Denise V; Koeppe, Roger E; Barrera, Francisco N; Feigenson, Gerald W

2018-05-08

A number of highly curved membranes in vivo, such as epithelial cell microvilli, have the relatively high sphingolipid content associated with "raft-like" composition. Given the much lower bending energy measured for bilayers with "nonraft" low sphingomyelin and low cholesterol content, observing high curvature for presumably more rigid compositions seems counterintuitive. To understand this behavior, we measured membrane rigidity by fluctuation analysis of giant unilamellar vesicles. We found that including a transmembrane helical GWALP peptide increases the membrane bending modulus of the liquid-disordered (Ld) phase. We observed this increase at both low-cholesterol fraction and higher, more physiological cholesterol fraction. We find that simplified, commonly used Ld and liquid-ordered (Lo) phases are not representative of those that coexist. When Ld and Lo phases coexist, GWALP peptide favors the Ld phase with a partition coefficient of 3-10 depending on mixture composition. In model membranes at high cholesterol fractions, Ld phases with GWALP have greater bending moduli than the Lo phase that would coexist. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Lamellar Biogels: Fluid-Membrane-Based Hydrogels Containing Polymer Lipids

NASA Astrophysics Data System (ADS)

Warriner, Heidi E.; Idziak, Stefan H. J.; Slack, Nelle L.; Davidson, Patrick; Safinya, Cyrus R.

1996-02-01

A class of lamellar biological hydrogels comprised of fluid membranes of lipids and surfactants with small amounts of low molecular weight poly(ethylene glycol)-derived polymer lipids (PEG-lipids) were studied by x-ray diffraction, polarized light microscopy, and rheometry. In contrast to isotropic hydrogels of polymer networks, these membrane-based birefringent liquid crystalline biogels, labeled Lα,g, form the gel phase when water is added to the liquid-like lamellar L_α phase, which reenters a liquid-like mixed phase upon further dilution. Furthermore, gels with larger water content require less PEG-lipid to remain stable. Although concentrated (~50 weight percent) mixtures of free PEG (molecular weight, 5000) and water do not gel, gelation does occur in mixtures containing as little as 0.5 weight percent PEG-lipid. A defining signature of the Lα,g regime as it sets in from the fluid lamellar L_α phase is the proliferation of layer-dislocation-type defects, which are stabilized by the segregation of PEG-lipids to the defect regions of high membrane curvature that connect the membranes.

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

Photoinitiated Bottom-Up Click Synthesis of Ion-Containing Networks as Hydroxide Exchange Membranes

NASA Astrophysics Data System (ADS)

Tibbits, Andrew Charles

Fuel cells are energy conversion devices which directly convert chemical energy into electrical energy and environmentally friendly byproducts (i.e., water) with potential versatility for transportation and portable applications. Hydroxide exchange membrane fuel cells (HEMFCs) have the potential to decrease the overall fuel cell cost through the utilization of non-precious metal catalysts such as nickel and silver as opposed to platinum which is used by the current standard technology, proton exchange membrane fuel cells (PEMFCs). However, substantial improvements in thermal and alkaline stability, hydroxide conductivity, mechanical flexibility, and processing are needed to create a competitive membrane for HEMFC applications. Regardless of the type of membrane, the high water uptake that is typically associated with increased ionic conductivity is problematic and can result in the dissolution of the membrane during fuel cell operation. Covalent crosslinking of the membrane is an approach which has been effectively applied to reduce water uptake without a significant compromise of the hydroxide conductivity. The synthesis and processing of membrane materials is vastly simplified by using click polymerization schemes. Click chemistry is a collection of organic chemical reactions that are rapid, selective, and high yielding. One of the most versatile and facile click reactions is the thiol-ene reaction, which is the radical-mediated addition reaction between a thiol (an -SH group) and an 'ene' (an electron rich vinyl group, C=C) in the presence of a photoinitiator and light. The click attributes of the thiol-ene reaction enables potential of "bottom-up" design of ion-containing polymers via a single step photoinitiated crosslinking reaction with precise control over structure and physicochemical properties not only for fuel cell membranes but also for a range of other applications including separations, sensors, flexible electronics, and coatings. However, a fundamental understanding of the formation and properties of ion-containing thiol-ene materials and their implementation as hydroxide exchange membranes is largely absent from the current literature. The work described herein will highlight the versatility of click reactions, primarily the thiol-ene reaction, for fabrication of ion-containing networks with tunable properties based on the rational design and synthesis of photopolymerizable ionic liquid comonomers with an emphasis on applicability for HEMFC applications. The role of ionic liquid monomer structure on the kinetics and mechanism of thiol-ene ionic network formation and the subsequent properties (i.e., ion conductive, thermomechanical, and structural) will be elucidated to establish a guided framework for click ionic material development. This framework will be directed onto the development of alkaline stable hydroxide-conductive membranes for fuel cell applications as well as the incorporation of catalytic nanoparticles into a photocrosslinkable formulation as a self-standing catalyst layer. Finally, novel approaches to membrane fabrication will be implemented to build on the foundational studies that will simultaneously enhance the ionic conductivity and mechanical properties of the ion-containing polymer materials: these approaches include the synthesis and crosslinking of photopolymerizable cationic surfactants for microphase separated membranes as well as the first "bottom-up" ion-containing polymer synthesized from the photoinitiated copper-catalyzed azide-alkyne cycloaddition (photo-CuAAC) reaction which exhibits enhanced processability and hydroxide conductivity (>50 mS/cm).

Composite polymer electrolyte containing ionic liquid and functionalized polyhedral oligomeric silsesquioxanes for anhydrous PEM applications.

PubMed

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

2009-06-01

A new type of supported liquid membrane was made by combining an ionic liquid (IL) with a Nafion membrane reinforced with multifunctional polyhedral oligomeric silsesquioxanes (POSSs) using a layer-by-layer strategy for anhydrous proton-exchange membrane (PEM) application. The POSS was functionalized by direct sulfonation, and the sulfonated POSS (S-POSS) was incorporated into Nafion 117 membranes by the infiltration method. The resultant hybrid membrane shows strong ionic interaction between the Nafion matrix and the multifunctional POSS, resulting in increased glass transition temperature and thermal stability at very low loadings of S-POSS (1%). The presence of S-POSS has also improved the proton conductivity especially at low humidities, where it shows a marked increase due to its confinement in the ionic domains and promotes water uptake by capillary condensation. In order to achieve anhydrous conductivity, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI) was incorporated into these membranes to provide proton conduction in the absence of water. Although the incorporation of an IL shows a plasticizing effect on the Nafion membrane, the S-POSS composite membrane with an IL shows a higher modulus at high temperatures compared to Nafion 117 and a Nafion-IL membrane, with significantly higher proton conductivity (5 mS/cm at 150 degrees C with 20% IL). This shows the ability of the multifunctional POSS and IL to work symbiotically to achieve the desirable proton conductivity and mechanical properties of such membranes by enhancing the ionic interaction within the material.

Deuterium Labeling Strategies for Creating Contrast in Structure-Function Studies of Model Bacterial Outer Membranes Using Neutron Reflectometry.

PubMed

Le Brun, Anton P; Clifton, Luke A; Holt, Stephen A; Holden, Peter J; Lakey, Jeremy H

2016-01-01

Studying the outer membrane of Gram-negative bacteria is challenging due to the complex nature of its structure. Therefore, simplified models are required to undertake structure-function studies of processes that occur at the outer membrane/fluid interface. Model membranes can be created by immobilizing bilayers to solid supports such as gold or silicon surfaces, or as monolayers on a liquid support where the surface pressure and fluidity of the lipids can be controlled. Both model systems are amenable to having their structure probed by neutron reflectometry, a technique that provides a one-dimensional depth profile through a membrane detailing its thickness and composition. One of the strengths of neutron scattering is the ability to use contrast matching, allowing molecules containing hydrogen and those enriched with deuterium to be highlighted or matched out against the bulk isotopic composition of the solvent. Lipopolysaccharides, a major component of the outer membrane, can be isolated for incorporation into model membranes. Here, we describe the deuteration of lipopolysaccharides from rough strains of Escherichia coli for incorporation into model outer membranes, and how the use of deuterated materials enhances structural analysis of model membranes by neutron reflectometry. © 2016 Elsevier Inc. All rights reserved.

Multi-chamber electroosmosis using textile reinforced agar membranes--A promising concept for the future of hemodialysis.

PubMed

Kofler, Markus; Lenninger, Margit; Mayer, Gert; Neuwirt, Hannes; Grimm, Michael; Bechtold, Thomas

2016-01-20

Renal replacement therapy options are limited to hemodialysis and peritoneal dialysis (70% of US patients) or renal transplantation. Diffusion processes are the main physico-chemical principle behind hemodialysis. An alternative way to achieve liquid flow through membranes bases on the electroosmotic flow which is observed as electrokinetic phenomenon in porous membranes which bear surface charges. Agar consists of the non-ionic agarose and the negatively charged agaropectine thus an electroosmotic flux is observed in analytical electrophoresis. In this study the potential electroosmosis on textile reinforced agar membranes as separation method was investigated. Using a five-chamber electrolysis cell and an agar membrane/cellulose fabric composite an intensive electroosmotic flow of 1-2 ml cm(2) h(-1) at 100 mA cell current could be observed. The movement of cations in the negatively charged agar structure led to an intensive electroosmotic flux, which also transported uncharged molecules such as urea, glucose through the membrane. Separation of uncharged low molecular weight molecules is determined by the membrane characteristic. The transport of ions (K(+), PO4(3-), creatinine) and uncharged molecules (urea, glucose) in electroosmotic separation experiments was monitored using a pH 5.5 phosphate electrolyte with the aim to assess the overall transport processes in the electrochemical cell. The results demonstrate the potential of the method for filtration of biological fluids in the absence of external pressure or high shear rates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioremediation and Detoxification of the Textile Wastewater with Membrane Bioreactor Using the White-rot Fungus and Reuse of Wastewater.

PubMed

Hossain, Kaizar; Quaik, Shlrene; Ismail, Norli; Rafatullah, Mohd; Avasan, Maruthi; Shaik, Rameeja

2016-09-01

Application of membrane technology to wastewater treatment has expanded over the last decades due to increasingly stringent legislation, greater opportunities for water reuse/recycling processes and continuing advancement in membrane technology. In the present study, a bench-scale submerged microfiltration membrane bioreactor (MBR) was used to assess the treatment of textile wastewater. The decolorization capacity of white-rot fungus coriolus versicolor was confirmed through agar plate and liquid batch studies. The temperature and pH of the reactor were controlled at 29±1°C and 4.5±2, respectively. The bioreactor was operated with an average flux of 0.05 m.d -1 (HRT=15hrs) for a month. Extensive growth of fungi and their attachment to the membrane led to its fouling and associated increase of the transmembrane pressure requiring a periodic withdrawal of sludge and membrane cleaning. However, stable decoloration activity (approx. 98%), BOD (40-50%), COD (50-67%) and total organic carbon (TOC) removal (>95%) was achieved using the entire system (fungi + membrane), while the contribution of the fungi culture alone for TOC removal, as indicated by the quality of the reactor supernatant, was 35-50% and 70%, respectively. The treated wastewater quality satisfied the requirement of water quality for dyeing and finishing process excluding light coloration. Therefore, textile wastewater reclamation and reuse is a promising alternative, which can both conserve or supplement the available water resource and reduce or eliminate the environmental pollution.

Phase transitions and size scaling of membrane-less organelles

PubMed Central

2013-01-01

The coordinated growth of cells and their organelles is a fundamental and poorly understood problem, with implications for processes ranging from embryonic development to oncogenesis. Recent experiments have shed light on the cell size–dependent assembly of membrane-less cytoplasmic and nucleoplasmic structures, including ribonucleoprotein (RNP) granules and other intracellular bodies. Many of these structures behave as condensed liquid-like phases of the cytoplasm/nucleoplasm. The phase transitions that appear to govern their assembly exhibit an intrinsic dependence on cell size, and may explain the size scaling reported for a number of structures. This size scaling could, in turn, play a role in cell growth and size control. PMID:24368804

Biological treatment of fracturing waste liquid in a membrane-coupled internal circulation aerobic biological fluidized bed with the assistance of coagulation.

PubMed

Tu, Yizhou; Liu, Xing-Peng; Li, Hui-Qiang; Yang, Ping

2017-12-01

Fracturing waste liquid (FWL) is generated during shale gas extraction and contains high concentrations of suspended solid, salinity and organic compounds, which needs proper management to prevent excessive environmental disruption. Biological treatment of the FWL was attempted in this study using a membrane-coupled internal circulation aerobic biological fluidized bed (MC-ICABFB) after being treated by coagulation. The results showed that poly aluminum chloride (PAC) of 30 g/L, polyacrylamide (PAM) of 20 mg/L and pH of 7.0 were suitable choices for coagulation. The pretreated FWL mixed with synthetic wastewater at different ratios were used as the influent wastewater for the reactor. The MC-ICABFB had relatively good performance on COD and NH 4 + -N removal and the main residual organic compound in the effluent was phthalates according to the analysis of GC-MC profiles. In addition, a suitable pretreatment process for the FWL to facilitate biological treatment of the wastewater needs further research.

Liquid permeation and chemical stability of anodic alumina membranes

PubMed Central

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

2017-01-01

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

A plasma modified cellulose-chitosan porous membrane allows efficient DNA binding and provides antibacterial properties: A step towards developing a new DNA collecting card.

PubMed

Chumwangwapee, Sasiwimon; Chingsungnoen, Artit; Siri, Sineenat

2016-11-01

In forensic DNA analyses, biological specimens are collected and stored for subsequent recovery and analysis of DNA. A cost-effective and efficient DNA recovery approach is therefore a need. This study aims to produce a plasma modified cellulose-chitosan membrane (pCE-CS) that efficiently binds and retains DNA as a potential DNA collecting card. The pCE-CS membrane was produced by a phase separation of ionic liquid dissolving CE and CS in water with subsequent surface-modification by a two-step exposure of argon plasma and nitrogen gas. Through plasma modification, the pCE-CS membrane demonstrated better DNA retention after a washing process and higher rate of DNA recovery as compared with the original CE-CS membrane and the commercial FTA card. In addition, the pCE-CS membrane exhibited anti-bacterial properties against both Escherichia coli and Staphylococcus aureus. The results of this work suggest a potential function of the pCE-CS membrane as a DNA collecting card with a high recovery rate of captured DNA. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Biofouling in forward osmosis systems: An experimental and numerical study.

PubMed

Bucs, Szilárd S; Valladares Linares, Rodrigo; Vrouwenvelder, Johannes S; Picioreanu, Cristian

2016-12-01

This study evaluates with numerical simulations supported by experimental data the impact of biofouling on membrane performance in a cross-flow forward osmosis (FO) system. The two-dimensional numerical model couples liquid flow with solute transport in the FO feed and draw channels, in the FO membrane support layer and in the biofilm developed on one or both sides of the membrane. The developed model was tested against experimental measurements at various osmotic pressure differences and in batch operation without and with the presence of biofilm on the membrane active layer. Numerical studies explored the effect of biofilm properties (thickness, hydraulic permeability and porosity), biofilm membrane surface coverage, and biofilm location on salt external concentration polarization and on the permeation flux. The numerical simulations revealed that (i) when biofouling occurs, external concentration polarization became important, (ii) the biofilm hydraulic permeability and membrane surface coverage have the highest impact on water flux, and (iii) the biofilm formed in the draw channel impacts the process performance more than when formed in the feed channel. The proposed mathematical model helps to understand the impact of biofouling in FO membrane systems and to develop possible strategies to reduce and control biofouling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fabrication and characterization of vertically aligned carbon-nanotube membranes

NASA Astrophysics Data System (ADS)

Castellano, Richard; Akin, Cevat; Purri, Matt; Shan, Jerry; Kim, Sangil; Fornasiero, Francesco

2015-11-01

Membranes having vertically-aligned carbon-nanotube (VACNT) pores offer promise as highly efficient and permeable membranes for use as breathable thin films, or in filtration and separation applications, among others. However, current membrane-fabrication techniques utilizing chemical-vapor-deposition-grown VACNT arrays are costly and difficult to scale up. We have developed a solution-based, electric-field-assisted approach as a cost-effective and scalable method to produce large-area VACNT membranes. Nanotubes are dispersed in a liquid polymer, and aligned and electrodeposited with the aid of an electric field prior to crosslinking the polymer to create VACNT membranes. We experimentally examine the electrodeposition process, focusing on parameters including the electric field, composition of the solution, and CNT functionalization that can affect the nanotube number density in the resulting membrane. We characterize the CNT pore size and number density and investigate the transport properties of the membrane. Size-exclusion tests are used to check for defects and infer the pore size of the VACNT membranes. Dry-gas membrane permeability is measured with a pressurized nitrogen-flow system, while moisture-vapor-transfer rate is measured with the ASTM-E96 upright-cup test. We discuss the measured transport properties of the solution-based, electric-field-fabricated VACNT membranes in reference to their application as breathable thin films. We would like to acknowledge DTRA for their funding and support of our research.

Effects of dissolved organic matters (DOMs) on membrane fouling in anaerobic ceramic membrane bioreactors (AnCMBRs) treating domestic wastewater.

PubMed

Yue, Xiaodi; Koh, Yoong Keat Kelvin; Ng, How Yong

2015-12-01

Anaerobic membrane bioreactors (AnMBRs) have been regarded as a potential solution to achieve energy neutrality in the future wastewater treatment plants. Coupling ceramic membranes into AnMBRs offers great potential as ceramic membranes are resistant to corrosive chemicals such as cleaning reagents and harsh environmental conditions such as high temperature. In this study, ceramic membranes with pore sizes of 80, 200 and 300 nm were individually mounted in three anaerobic ceramic membrane bioreactors (AnCMBRs) treating real domestic wastewater to examine the treatment efficiencies and to elucidate the effects of dissolved organic matters (DOMs) on fouling behaviours. The average overall chemical oxygen demands (COD) removal efficiencies could reach around 86-88%. Although CH4 productions were around 0.3 L/g CODutilised, about 67% of CH4 generated was dissolved in the liquid phase and lost in the permeate. When filtering mixed liquor of similar properties, smaller pore-sized membranes fouled slower in long-term operations due to lower occurrence of pore blockages. However, total organic removal efficiencies could not explain the fouling behaviours. Liquid chromatography-organic carbon detection, fluorescence spectrophotometer and high performance liquid chromatography coupled with fluorescence and ultra-violet detectors were used to analyse the DOMs in detail. The major foulants were identified to be biopolymers that were produced in microbial activities. One of the main components of biopolymers--proteins--led to different fouling behaviours. It is postulated that the proteins could pass through porous cake layers to create pore blockages in membranes. Hence, concentrations of the DOMs in the soluble fraction of mixed liquor (SML) could not predict membrane fouling because different components in the DOMs might have different interactions with membranes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

PubMed Central

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-01-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of “smart” textiles and functional membranes for various applications. PMID:24129357

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

NASA Astrophysics Data System (ADS)

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-10-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of ``smart'' textiles and functional membranes for various applications.

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 ...

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.

Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport.

PubMed

Sheng, Zhizhi; Wang, Honglong; Tang, Yongliang; Wang, Miao; Huang, Lizhi; Min, Lingli; Meng, Haiqiang; Chen, Songyue; Jiang, Lei; Hou, Xu

2018-02-01

The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gases and liquids under a steady-state applied pressure, nearly eliminate fouling, and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores' deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles.

Liquid gating elastomeric porous system with dynamically controllable gas/liquid transport

PubMed Central

Sheng, Zhizhi; Wang, Honglong; Tang, Yongliang; Wang, Miao; Huang, Lizhi; Min, Lingli; Meng, Haiqiang; Chen, Songyue; Jiang, Lei; Hou, Xu

2018-01-01

The development of membrane technology is central to fields ranging from resource harvesting to medicine, but the existing designs are unable to handle the complex sorting of multiphase substances required for many systems. Especially, the dynamic multiphase transport and separation under a steady-state applied pressure have great benefits for membrane science, but have not been realized at present. Moreover, the incorporation of precisely dynamic control with avoidance of contamination of membranes remains elusive. We show a versatile strategy for creating elastomeric microporous membrane-based systems that can finely control and dynamically modulate the sorting of a wide range of gases and liquids under a steady-state applied pressure, nearly eliminate fouling, and can be easily applied over many size scales, pressures, and environments. Experiments and theoretical calculation demonstrate the stability of our system and the tunability of the critical pressure. Dynamic transport of gas and liquid can be achieved through our gating interfacial design and the controllable pores’ deformation without changing the applied pressure. Therefore, we believe that this system will bring new opportunities for many applications, such as gas-involved chemical reactions, fuel cells, multiphase separation, multiphase flow, multiphase microreactors, colloidal particle synthesis, and sizing nano/microparticles. PMID:29487906

Dynamics of the Glycophorin A Dimer in Membranes of Native-Like Composition Uncovered by Coarse-Grained Molecular Dynamics Simulations

PubMed Central

Flinner, Nadine; Schleiff, Enrico

2015-01-01

Membranes are central for cells as borders to the environment or intracellular organelle definition. They are composed of and harbor different molecules like various lipid species and sterols, and they are generally crowded with proteins. The membrane system is very dynamic and components show lateral, rotational and translational diffusion. The consequence of the latter is that phase separation can occur in membranes in vivo and in vitro. It was documented that molecular dynamics simulations of an idealized plasma membrane model result in formation of membrane areas where either saturated lipids and cholesterol (liquid-ordered character, Lo) or unsaturated lipids (liquid-disordered character, Ld) were enriched. Furthermore, current discussions favor the idea that proteins are sorted into the liquid-disordered phase of model membranes, but experimental support for the behavior of isolated proteins in native membranes is sparse. To gain insight into the protein behavior we built a model of the red blood cell membrane with integrated glycophorin A dimer. The sorting and the dynamics of the dimer were subsequently explored by coarse-grained molecular dynamics simulations. In addition, we inspected the impact of lipid head groups and the presence of cholesterol within the membrane on the dynamics of the dimer within the membrane. We observed that cholesterol is important for the formation of membrane areas with Lo and Ld character. Moreover, it is an important factor for the reproduction of the dynamic behavior of the protein found in its native environment. The protein dimer was exclusively sorted into the domain of Ld character in the model red blood cell plasma membrane. Therefore, we present structural information on the glycophorin A dimer distribution in the plasma membrane in the absence of other factors like e.g. lipid anchors in a coarse grain resolution. PMID:26222139

Biochemicals from food waste and recalcitrant biomass via syngas fermentation: A review.

PubMed

Wainaina, Steven; Horváth, Ilona Sárvári; Taherzadeh, Mohammad J

2018-01-01

An effective method for the production of value-added chemicals from food waste and lignocellulosic materials is a hybrid thermal-biological process, which involves gasification of the solid materials to syngas (primarily CO and H 2 ) followed by fermentation. This paper reviews the recent advances in this process. The special focus is on the cultivation methods that involve the use of single strains, defined mixed cultures and undefined mixed cultures for production of carboxylic acids and higher alcohols. A rate limiting step in these processes is the low mass transfer between the gas and the liquid phases. Therefore, novel techniques that can enhance the gas-liquid mass transfer including membrane- and trickle-bed bioreactors were discussed. Such bioreactors have shown promising results in increasing the volumetric mass transfer coefficient (k L a). High gas pressure also influences the mass transfer in certain batch processes, although the presence of impurities in the gas would impede the process. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

Langmaier, Jan; Samec, Zdenek

2009-08-01

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

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

PubMed

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

2012-08-16

An adaptive self-healing ionic liquid nanocomposite membrane comprising a multi-layer support structure hosting the ionic salt [Ag](+) [Tf(2) N](-) is used for the separation of the olefin propylene and the paraffin propane. The ionic salt renders liquid like upon complexation with propylene, resulting in facilitated transport of propylene over propane at benchmark-setting selectivity and permeance levels. The contacting with acetylene causes the ionic salt to liquefy without showing evidence of forming explosive silver acetylide. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Agricultural and Food Processing Applications of Pulsed Power Technology

NASA Astrophysics Data System (ADS)

Takaki, Koichi; Ihara, Satoshi

Recent progress of agricultural and food processing applications of pulsed power is described in this paper. Repetitively operated compact pulsed power generators with a moderate peak power have been developed for the agricultural and the food processing applications. These applications are mainly based on biological effects and can be categorized as decontamination of air and liquid, germination promotion, inhabitation of saprophytes growth, extraction of juice from fruits and vegetables, and fertilization of liquid medium, etc. Types of pulsed power that have biological effects are caused with gas discharges, water discharges, and electromagnetic fields. The discharges yield free radicals, UV radiation, intense electric field, and shock waves. Biologically based applications of pulsed power are performed by selecting the type that gives the target objects the adequate result from among these agents or byproducts. For instance, intense electric fields form pores on the cell membrane, which is called electroporation, or influence the nuclei.

Liquid Junction and Membrane Potentials of the Squid Giant Axon

PubMed Central

Cole, Kenneth S.; Moore, John W.

1960-01-01

The potential differences across the squid giant axon membrane, as measured with a series of microcapillary electrodes filled with concentrations of KCl from 0.03 to 3.0 M or sea water, are consistent with a constant membrane potential and the liquid junction potentials calculated by the Henderson equation. The best value for the mobility of an organic univalent ion, such as isethionate, leads to a probably low, but not impossible, axoplasm specific resistance of 1.2 times sea water and to a liquid junction correction of 4 mv. for microelectrodes filled with 3 M KCl. The errors caused by the assumptions of proportional mixing, unity activity coefficients, and a negligible internal fixed charge cannot be estimated but the results suggest that the cumulative effect of them may not be serious. PMID:13811119

Method of removing and detoxifying a phosphorus-based substance

DOEpatents

Vandegrift, George F.; Steindler, Martin J.

1989-01-01

A method of removing organic phosphorus-based poisonous substances from water contaminated therewith and of subsequently destroying the toxicity of the substance is disclosed. Initially, a water-immiscible organic is immobilized on a supported liquid membrane. Thereafter, the contaminated water is contacted with one side of the supported liquid membrane to selectively dissolve the phosphorus-based substance in the organic extractant. At the same time, the other side of the supported liquid membrane is contacted with a hydroxy-affording strong base to react the phosphorus-based substance dissolved by the organic extractant with a hydroxy ion. This forms a non-toxic reaction product in the base. The organic extractant can be a water-insoluble trialkyl amine, such as trilauryl amine. The phosphorus-based substance can be phosphoryl or a thiophosphoryl.

The nanoaquarium: A nanofluidic platform for in situ transmission electron microscopy in liquid media

NASA Astrophysics Data System (ADS)

Grogan, Joseph M.

There are many scientifically interesting and technologically relevant nanoscale phenomena that take place in liquid media. Examples include aggregation and assembly of nanoparticles; colloidal crystal formation; liquid phase growth of structures such as nanowires; electrochemical deposition and etching for fabrication processes and battery applications; interfacial phenomena; boiling and cavitation; and biological interactions. Understanding of these fields would benefit greatly from real-time, in situ transmission electron microscope (TEM) imaging with nanoscale resolution. Most liquids cannot be imaged by traditional TEM due to evaporation in the high vacuum environment and the requirement that samples be very thin. Liquid-cell in situ TEM has emerged as an exciting new experimental technique that hermetically seals a thin slice of liquid between two electron transparent membranes to enable TEM imaging of liquid-based processes. This work presents details of the fabrication of a custom-made liquid-cell in situ TEM device, dubbed the nanoaquarium. The nanoaquarium's highlights include an exceptionally thin sample cross section (10s to 100s of nm); wafer scale processing that enables high-yield mass production; robust hermetic sealing that provides leak-free operation without use of glue, epoxy, or any polymers; compatibility with lab-on-chip technology; and on-chip integrated electrodes for sensing and actuation. The fabrication process is described, with an emphasis on direct wafer bonding. Experimental results involving direct observation of colloid aggregation using an aqueous solution of gold nanoparticles are presented. Quantitative analysis of the growth process agrees with prior results and theory, indicating that the experimental technique does not radically alter the observed phenomenon. For the first time, in situ observations of nanoparticles at a contact line and in an evaporating thin film of liquid are reported, with applications for techniques such as dip-coating and drop-casting, commonly used for depositing nanoparticles on a surface via convective-capillary assembly. Theoretical analysis suggests that the observed particle motion and aggregation are caused by gradients in surface tension and disjoining pressure in the thin liquid film.

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. © 2016 Poultry Science Association Inc.

Further development of a robust workup process for solution-phase high-throughput library synthesis to address environmental and sample tracking issues.

PubMed

Kuroda, Noritaka; Hird, Nick; Cork, David G

2006-01-01

During further improvement of a high-throughput, solution-phase synthesis system, new workup tools and apparatus for parallel liquid-liquid extraction and evaporation have been developed. A combination of in-house design and collaboration with external manufacturers has been used to address (1) environmental issues concerning solvent emissions and (2) sample tracking errors arising from manual intervention. A parallel liquid-liquid extraction unit, containing miniature high-speed magnetic stirrers for efficient mixing of organic and aqueous phases, has been developed for use on a multichannel liquid handler. Separation of the phases is achieved by dispensing them into a newly patented filter tube containing a vertical hydrophobic porous membrane, which allows only the organic phase to pass into collection vials positioned below. The vertical positioning of the membrane overcomes the hitherto dependence on the use of heavier-than-water, bottom-phase, organic solvents such as dichloromethane, which are restricted due to environmental concerns. Both small (6-mL) and large (60-mL) filter tubes were developed for parallel phase separation in library and template synthesis, respectively. In addition, an apparatus for parallel solvent evaporation was developed to (1) remove solvent from the above samples with highly efficient recovery and (2) avoid the movement of individual samples between their collection on a liquid handler and registration to prevent sample identification errors. The apparatus uses a diaphragm pump to achieve a dynamic circulating closed system with a heating block for the rack of 96 sample vials and an efficient condenser to trap the solvents. Solvent recovery is typically >98%, and convenient operation and monitoring has made the apparatus the first choice for removal of volatile solvents.

Evolution and development of model membranes for physicochemical and functional studies of the membrane lateral heterogeneity.

PubMed

Morigaki, Kenichi; Tanimoto, Yasushi

2018-03-14

One of the main questions in the membrane biology is the functional roles of membrane heterogeneity and molecular localization. Although segregation and local enrichment of protein/lipid components (rafts) have been extensively studied, the presence and functions of such membrane domains still remain elusive. Along with biochemical, cell observation, and simulation studies, model membranes are emerging as an important tool for understanding the biological membrane, providing quantitative information on the physicochemical properties of membrane proteins and lipids. Segregation of fluid lipid bilayer into liquid-ordered (Lo) and liquid-disordered (Ld) phases has been studied as a simplified model of raft in model membranes, including giant unilamellar vesicles (GUVs), giant plasma membrane vesicles (GPMVs), and supported lipid bilayers (SLB). Partition coefficients of membrane proteins between Lo and Ld phases were measured to gauze their affinities to lipid rafts (raftophilicity). One important development in model membrane is patterned SLB based on the microfabrication technology. Patterned Lo/Ld phases have been applied to study the partition and function of membrane-bound molecules. Quantitative information of individual molecular species attained by model membranes is critical for elucidating the molecular functions in the complex web of molecular interactions. The present review gives a short account of the model membranes developed for studying the lateral heterogeneity, especially focusing on patterned model membranes on solid substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

Recovery of ammonia from domestic wastewater effluents as liquid fertilizers by integration of natural zeolites and hollow fibre membrane contactors.

PubMed

Sancho, I; Licon, E; Valderrama, C; de Arespacochaga, N; López-Palau, S; Cortina, J L

2017-04-15

The integration of up-concentration processes to increase the efficiency of primary sedimentation, as a solution to achieve energy neutral wastewater treatment plants, requires further post-treatment due to the missing ammonium removal stage. This study evaluated the use of zeolites as a post-treatment step, an alternative to the biological removal process. A natural granular clinoptilolite zeolite was evaluated as a sorbent media to remove low levels (up to 100mg-N/L) of ammonium from treated wastewater using batch and fixed bed columns. After being activated to the Na-form (Z-Na), the granular zeolite shown an ammonium exchange capacity of 29±0.8mgN-NH 4 + /g in single ammonium solutions and 23±0.8mgN-NH 4 + /g in treated wastewater simulating up-concentration effluent at pH=8. The equilibrium removal data were well described by the Langmuir isotherm. The ammonium adsorption into zeolites is a very fast process when compared with polymeric materials (zeolite particle diffusion coefficient around 3×10 -12 m 2 /s). Column experiments with solutions containing 100mgN-NH 4 + /L provide effective sorption and elution rates with concentration factors between 20 and 30 in consecutive operation cycles. The loaded zeolite was regenerated using 2g NaOH/L solution and the rich ammonium/ammonia concentrates 2-3g/L in NaOH were used in a liquid-liquid membrane contactor system in a closed-loop configuration with nitric and phosphoric acid as stripping solutions. The ammonia recovery ratio exceeded 98%. Ammonia nitrate and di-ammonium phosphate concentrated solutions reached up to 2-5% wt. of N. Copyright © 2017 Elsevier B.V. All rights reserved.

Glass microfluidic devices with thin membrane voltage junctions for electrospray mass spectrometry.

PubMed

Yue, Guihua Eileen; Roper, Michael G; Jeffery, Erin D; Easley, Christopher J; Balchunas, Catherine; Landers, James P; Ferrance, Jerome P

2005-06-01

In this study a novel glass membrane was prepared for conducting high voltage (HV) to solution in the channel of a microfabricated device for generation of liquid electrospray. Taylor cone formation and mass spectra obtained from this microdevice confirmed the utility of the glass membrane, but voltage conduction through the membrane could not be successfully explained based solely on the conductivity of the glass itself. This novel method for developing a high-voltage interface for microdevices avoids direct metal/liquid contact eliminating bubble formation in the channel due to water hydrolysis on the surface of the metal. Further, this arrangement produces no dead volume as is often found with traditional liquid junctions. At the same time, preliminary investigations into the outlet design of glass microdevices for interfacing with electrospray mass spectrometry, was explored. Both the exit shape and the use of hydrophobic coatings at the channel exit of the microdevice electrospray interface were evaluated using standard proteins with results indicating the utility of this type of design after further optimization.

Stability limit of liquid water in metastable equilibrium with subsaturated vapors.

PubMed

Wheeler, Tobias D; Stroock, Abraham D

2009-07-07

A pure liquid can reach metastable equilibrium with its subsaturated vapor across an appropriate membrane. This situation is analogous to osmotic equilibrium: the reduced chemical potential of the dilute phase (the subsaturated vapor) is compensated by a difference in pressure between the phases. To equilibrate with subsaturated vapor, the liquid phase assumes a pressure that is lower than its standard vapor pressure, such that the liquid phase is metastable with respect to the vapor phase. For sufficiently subsaturated vapors, the liquid phase can even assume negative pressures. The appropriate membrane for this metastable equilibrium must provide the necessary mechanical support to sustain the difference in pressure between the two phases, limit nonhomogeneous mechanisms of cavitation, and resist the entry of the dilutant (gases) into the pure phase (liquid). In this article, we present a study of the limit of stability of liquid water--the degree of subsaturation at which the liquid cavitates--in this metastable state within microscale voids embedded in hydrogel membranes. We refer to these structures as vapor-coupled voids (VCVs). In these VCVs, we observed that liquid water cavitated when placed in equilibrium with vapors of activity aw,vapair

Effects of different fermentation methods on bacterial cellulose and acid production by Gluconacetobacter xylinus in Cantonese-style rice vinegar.

PubMed

Fu, Liang; Chen, Siqian; Yi, Jiulong; Hou, Zongxia

2014-07-01

A strain of acidogenic bacterium was isolated from the fermentation liquid of Cantonese-style rice vinegar produced by traditional surface fermentation. 16S rDNA identification confirmed the bacterium as Gluconacetobacter xylinus, which synthesizes bacterial cellulose, and the acid productivity of the strain was investigated. In the study, the effects of the membrane integrity and the comparison of the air-liquid interface membrane with immerged membrane on total acidity, cellulose production, alcohol dehydrogenase (ADH) activity and number of bacteria were investigated. The cellulose membrane and the bacteria were observed under SEM for discussing their relationship. The correlations between oxygen consumption and total acid production rate were compared in surface and shake flask fermentation. The results showed the average acid productivity of the strain was 0.02g/(100mL/h), and the integrity of cellulose membrane in surface fermentation had an important effect on total acidity and cellulose production. With a higher membrane integrity, the total acidity after 144 h of fermentation was 3.75 g/100 mL, and the cellulose production was 1.71 g/100 mL after 360 h of fermentation. However, when the membrane was crushed by mechanical force, the total acidity and the cellulose production were as low as 0.36 g/100 mL and 0.14 g/100 mL, respectively. When the cellulose membrane was forced under the surface of fermentation liquid, the total acid production rate was extremely low, but the activity of ADH in the cellulose membrane was basically the same with the one above the liquid surface. The bacteria were mainly distributed in the cellulose membrane during the fermentation. The bacterial counts in surface fermentation were more than in the shake flask fermentation and G. xylinus consumed the substrate faster, in surface fermentation than in shake flask fermentation. The oxygen consumption rate and total acid production rate of surface fermentation were respectively 26.13 times and 2.92 times that of shake flask fermentation.

A dielectric elastomer actuator coupled with water: snap-through instability and giant deformation

NASA Astrophysics Data System (ADS)

Godaba, Hareesh; Foo, Choon Chiang; Zhang, Zhi Qian; Khoo, Boo Cheong; Zhu, Jian

2015-04-01

A dielectric elastomer actuator is one class of soft actuators which can deform in response to voltage. Dielectric elastomer actuators coupled with liquid have recently been developed as soft pumps, soft lenses, Braille displays, etc. In this paper, we conduct experiments to investigate the performance of a dielectric elastomer actuator which is coupled with water. The membrane is subject to a constant water pressure, which is found to significantly affect the electromechanical behaviour of the membrane. When the pressure is small, the membrane suffers electrical breakdown before snap-through instability, and achieves a small voltage-induced deformation. When the pressure is higher to make the membrane near the verge of the instability, the membrane can achieve a giant voltage-induced deformation, with an area strain of 1165%. When the pressure is large, the membrane suffers pressure-induced snap-through instability and may collapse due to a large amount of liquid enclosed by the membrane. Theoretical analyses are conducted to interpret these experimental observations.

Effect of addition of Proline, ionic liquid [Choline][Pro] on CO2 separation properties of poly(amidoamine) dendrimer / poly(ethylene glycol) hybrid membranes

NASA Astrophysics Data System (ADS)

Duan, S. H.; Kai, T.; Chowdhury, F. A.; Taniguchi, I.; Kazama, S.

2018-01-01

Poly(amidoamine) (PAMAM) dendrimers were incorporated into cross-linked poly(ethylene glycol) (PEGDMA) matrix to improve carbon dioxide (CO2) separation performance at elevated pressures. In our previous studies, PAMAM/PEGDMA hybrid membranes showed high CO2 separation properties from CO2/H2 mixed gases. In this study, proline, choline and ionic liquid [Choline][Pro] compounds were selected as rate promoters that were used to prepare PAMAM/PEGDMA hybrid membranes. The effect of addition of proline, choline, IL [Choline][Pro] on separation performance of PAMAM/PEGDMA) hybrid membranes for CO2/H2 separation was investigated. Amino acid proline, choline, and IL [Choline][Pro] were used to promote CO2 and amine reaction. With the addition of [Choline][Pro] into PAMAM/PEG membrane, CO2 permeance of PAMAM/PEG hybrid membranes are increased up to 46% without any change of selectivity of membrane for CO2.

Membrane rafts stabilized by chiral liquid crystal correction to bare interfacial tension

NASA Astrophysics Data System (ADS)

Kang, Louis; Lubensky, T. C.

Lipid rafts are hypothesized to facilitate protein interaction, tension regulation, and trafficking in biological membranes, but the mechanisms responsible for their formation and maintenance are not clear. Recently, experiments showed that bidisperse mixtures of filamentous viruses can self-assemble into colloidal monolayers with thermodynamically stable rafts that exhibit chiral structure and repulsive interactions. We quantitatively explain these observations by modeling the membrane particles as chiral liquid crystals. Chiral twist promotes the formation of finite-sized rafts by decreasing the effective interfacial tension between rafts and background membrane. It also mediates a repulsion that distributes rafts evenly throughout the membrane. Although this system is composed of filamentous viruses whose aggregation is entropically driven by dextran depletants instead of phospholipids and cholesterol with prominent electrostatic interactions, colloidal and biological membranes share many of the same physical symmetries. Chiral twist can contribute to the behavior of both systems and may account for certain stereospecific effects observed in molecular membranes.

Aspirin locally disrupts the liquid-ordered phase

NASA Astrophysics Data System (ADS)

Alsop, Richard J.; Himbert, Sebastian; Dhaliwal, Alexander; Schmalzl, Karin; Rheinstädter, Maikel C.

2018-02-01

Local structure and dynamics of lipid membranes play an important role in membrane function. The diffusion of small molecules, the curvature of lipids around a protein and the existence of cholesterol-rich lipid domains (rafts) are examples for the membrane to serve as a functional interface. The collective fluctuations of lipid tails, in particular, are relevant for diffusion of membrane constituents and small molecules in and across membranes, and for structure and formation of membrane domains. We studied the effect of aspirin (acetylsalicylic acid, ASA) on local structure and dynamics of membranes composed of dimyristoylphosphocholine (DMPC) and cholesterol. Aspirin is a common analgesic, but is also used in the treatment of cholesterol. Using coherent inelastic neutron scattering experiments and molecular dynamics (MD) simulations, we present evidence that ASA binds to liquid-ordered, raft-like domains and disturbs domain organization and dampens collective fluctuations. By hydrogen-bonding to lipid molecules, ASA forms `superfluid' complexes with lipid molecules that can organize laterally in superlattices and suppress cholesterol's ordering effect.

Digital holographic microscopy of phase separation in multicomponent lipid membranes

NASA Astrophysics Data System (ADS)

Farzam Rad, Vahideh; Moradi, Ali-Reza; Darudi, Ahmad; Tayebi, Lobat

2016-12-01

Lateral in-homogeneities in lipid compositions cause microdomains formation and change in the physical properties of biological membranes. With the presence of cholesterol and mixed species of lipids, phospholipid membranes segregate into lateral domains of liquid-ordered and liquid-disordered phases. Coupling of two-dimensional intralayer phase separations and interlayer liquid-crystalline ordering in multicomponent membranes has been previously demonstrated. By the use of digital holographic microscopy (DHMicroscopy), we quantitatively analyzed the volumetric dynamical behavior of such membranes. The specimens are lipid mixtures composed of sphingomyelin, cholesterol, and unsaturated phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine. DHMicroscopy in a transmission mode is an effective tool for quantitative visualization of phase objects. By deriving the associated phase changes, three-dimensional information on the morphology variation of lipid stacks at arbitrary time scales is obtained. Moreover, the thickness distribution of the object at demanded axial planes can be obtained by numerical focusing. Our results show that the volume evolution of lipid domains follows approximately the same universal growth law of previously reported area evolution. However, the thickness of the domains does not alter significantly by time; therefore, the volume evolution is mostly attributed to the changes in area dynamics. These results might be useful in the field of membrane-based functional materials.

The influence of mesoscopic confinement on the dynamics of imidazolium-based room temperature ionic liquids in polyether sulfone membranes.

PubMed

Thomaz, Joseph E; Bailey, Heather E; Fayer, Michael D

2017-11-21

The structural dynamics of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C n mimNTf 2 , n = 2, 4, 6, 10: ethyl-Emim; butyl-Bmim; hexyl-Hmim; decyl-Dmim) room temperature ionic liquids confined in the pores of polyether sulfone (PES 200) membranes with an average pore size of ∼350 nm and in the bulk liquids were studied. Time correlated single photon counting measurements of the fluorescence of the fluorophore coumarin 153 (C153) were used to observe the time-dependent Stokes shift (solvation dynamics). The solvation dynamics of C153 in the ionic liquids are multiexponential decays. The multiexponential functional form of the decays was confirmed as the slowest decay component of each bulk liquid matches the slowest component of the liquid dynamics measured by optical heterodyne-detected optical Kerr effect (OHD-OKE) experiments, which is single exponential. The fact that the slowest component of the Stokes shift matches the OHD-OKE data in all four liquids identifies this component of the solvation dynamics as arising from the complete structural randomization of the liquids. Although the pores in the PES membranes are large, confinement on the mesoscopic length scale results in substantial slowing of the dynamics, a factor of ∼4, for EmimNTf 2 , with the effect decreasing as the chain length increases. By DmimNTf 2 , the dynamics are virtually indistinguishable from those in the bulk liquid. The rotation relaxation of C153 in the four bulk liquids was also measured and showed strong coupling between the C153 probe and its environment.

The influence of mesoscopic confinement on the dynamics of imidazolium-based room temperature ionic liquids in polyether sulfone membranes

NASA Astrophysics Data System (ADS)

Thomaz, Joseph E.; Bailey, Heather E.; Fayer, Michael D.

2017-11-01

The structural dynamics of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (CnmimNTf2, n = 2, 4, 6, 10: ethyl—Emim; butyl—Bmim; hexyl—Hmim; decyl—Dmim) room temperature ionic liquids confined in the pores of polyether sulfone (PES 200) membranes with an average pore size of ˜350 nm and in the bulk liquids were studied. Time correlated single photon counting measurements of the fluorescence of the fluorophore coumarin 153 (C153) were used to observe the time-dependent Stokes shift (solvation dynamics). The solvation dynamics of C153 in the ionic liquids are multiexponential decays. The multiexponential functional form of the decays was confirmed as the slowest decay component of each bulk liquid matches the slowest component of the liquid dynamics measured by optical heterodyne-detected optical Kerr effect (OHD-OKE) experiments, which is single exponential. The fact that the slowest component of the Stokes shift matches the OHD-OKE data in all four liquids identifies this component of the solvation dynamics as arising from the complete structural randomization of the liquids. Although the pores in the PES membranes are large, confinement on the mesoscopic length scale results in substantial slowing of the dynamics, a factor of ˜4, for EmimNTf2, with the effect decreasing as the chain length increases. By DmimNTf2, the dynamics are virtually indistinguishable from those in the bulk liquid. The rotation relaxation of C153 in the four bulk liquids was also measured and showed strong coupling between the C153 probe and its environment.

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 ...

Ion-Selective Electrodes.

ERIC Educational Resources Information Center

Arnold, Mark A.; Meyerhoff, Mark E.

1984-01-01

Literature on ion-selective electrodes (ISEs) is reviewed in seven sections: books, conferences, reviews; potentiometric membrane electrodes; glass and solid-state membrane electrodes; liquid and polymer membrane ISEs; coated wire electrodes, ion-selective field effect transistors, and microelectrodes; gas sensors and selective bioelectrode…

Versatile Miniature Tunable Liquid Lenses Using Transparent Graphene Electrodes.

PubMed

Shahini, Ali; Xia, Jinjun; Zhou, Zhixian; Zhao, Yang; Cheng, Mark Ming-Cheng

2016-02-16

This paper presents, for the first time, versatile and low-cost miniature liquid lenses with graphene as electrodes. Tunable focal length is achieved by changing the droplet curvature using electrowetting on dielectric (EWOD). Ionic liquid and KCl solution are utilized as lens liquid on the top of a flexible Teflon-coated PDMS/parylene membrane. Transparent and flexible, graphene allows transmission of visible light as well as large deformation of the polymer membrane to achieve requirements for different lens designs and to increase the field of view without damaging of electrodes. The tunable range for the focal length is between 3 and 7 mm for a droplet with a volume of 3 μL. The visualization of bone marrow dendritic cells is demonstrated by the liquid lens system with a high resolution (456 lp/mm).

Nuclear magnetic resonance of liquid crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emsley, J.W.

1984-01-01

The phenomenon of liquid crystallinity has been known for 100 years, but it is only in recent years that our modern methods have yielded an understanding of this fascinating and important subject in terms of molecular behavior. The great improvements in NMR spectrometers have led to a rapid growth in the study of liquid crystalline systems; concurrently, the increased use of these systems in electro-optic displays, in soaps and membranes, have all focused increased attention on liquid crystallinity. The emphasis is placed first on giving an account of the theory of both the spectroscopy and the liquid crystalline state. Thismore » is followed by descriptions of experiments and their application to thermotropic phases, including discotics, to lyotropics, and finally to the very complex biological membranes.« less

Acquisition of Co metal from spent lithium-ion battery using emulsion liquid membrane technology and emulsion stability test

NASA Astrophysics Data System (ADS)

Yuliusman; Wulandari, P. T.; Amiliana, R. A.; Huda, M.; Kusumadewi, F. A.

2018-03-01

Lithium-ion batteries are the most common type to be used as energy source in mobile phone. The amount of lithium-ion battery wastes is approximated by 200 – 500 ton/year. In one lithium-ion battery, there are 5 – 20% of cobalt metal, depend on the manufacturer. One of the way to recover a valuable metal from waste is leaching process then continued with extraction, which is the aim of this study. Spent lithium-ion batteries will be characterized with EDX and AAS, the result will show the amount of cobalt metal with form of LiCoO2 in the cathode. Hydrochloric acid concentration used is 4 M, temperature 80°C, and reaction time 1 hour. This study will discuss the emulsion stability test on emulsion liquid membrane. The purpose of emulsion stability test in this study was to determine optimum concentration of surfactant and extractant to produce a stable emulsion. Surfactant and extractant used were SPAN 80 and Cyanex 272 respectively with both concentrations varied. Membrane and feed phase ratios used in this experiment was 1 : 2. The optimum results of this study were SPAN 80 concentrations of 10% w/v and Cyanex 272 0.7 M.

Extraction of anionic dye from aqueous solutions by emulsion liquid membrane.

PubMed

Dâas, Attef; Hamdaoui, Oualid

2010-06-15

In this work, the extraction of Congo red (CR), an anionic disazo direct dye, from aqueous solutions by emulsion liquid membrane (ELM) was investigated. The important operational parameters governing emulsion stability and extraction behavior of dye were studied. The extraction of CR was influenced by a number of variables such as surfactant concentration, stirring speed, acid concentration in the feed solution and volume ratios of internal phase to organic phase and of emulsion to feed solution. Under most favorable conditions, practically all the CR molecules present in the feed phase were extracted even in the presence of salt (NaCl). At the optimum experimental conditions, total removal of antharaquinonic dye Acid Blue 25 was attained after only 10 min. Influence of sodium carbonate concentration as internal receiving phase on the stripping efficiency of CR was examined. The best sodium carbonate concentration in the internal phase that conducted to excellent stripping efficiency (>99%) and emulsion stability was 0.1N. The membrane recovery was total and the permeation of CR was not decreased up to seven runs. ELM process is a promising alternative to conventional methods and should increase awareness of the potential for recovery of anionic dyes. Copyright 2010 Elsevier B.V. All rights reserved.

Biophysical Model of Ion Transport across Human Respiratory Epithelia Allows Quantification of Ion Permeabilities

PubMed Central

Garcia, Guilherme J.M.; Boucher, Richard C.; Elston, Timothy C.

2013-01-01

Lung health and normal mucus clearance depend on adequate hydration of airway surfaces. Because transepithelial osmotic gradients drive water flows, sufficient hydration of the airway surface liquid depends on a balance between ion secretion and absorption by respiratory epithelia. In vitro experiments using cultures of primary human nasal epithelia and human bronchial epithelia have established many of the biophysical processes involved in airway surface liquid homeostasis. Most experimental studies, however, have focused on the apical membrane, despite the fact that ion transport across respiratory epithelia involves both cellular and paracellular pathways. In fact, the ion permeabilities of the basolateral membrane and paracellular pathway remain largely unknown. Here we use a biophysical model for water and ion transport to quantify ion permeabilities of all pathways (apical, basolateral, paracellular) in human nasal epithelia cultures using experimental (Ussing Chamber and microelectrode) data reported in the literature. We derive analytical formulas for the steady-state short-circuit current and membrane potential, which are for polarized epithelia the equivalent of the Goldman-Hodgkin-Katz equation for single isolated cells. These relations allow parameter estimation to be performed efficiently. By providing a method to quantify all the ion permeabilities of respiratory epithelia, the model may aid us in understanding the physiology that regulates normal airway surface hydration. PMID:23442922

Water permeation through anion exchange membranes

NASA Astrophysics Data System (ADS)

Luo, Xiaoyan; Wright, Andrew; Weissbach, Thomas; Holdcroft, Steven

2018-01-01

An understanding of water permeation through solid polymer electrolyte (SPE) membranes is crucial to offset the unbalanced water activity within SPE fuel cells. We examine water permeation through an emerging class of anion exchange membranes, hexamethyl-p-terphenyl poly (dimethylbenzimidazolium) (HMT-PMBI), and compare it against series of membrane thickness for a commercial anion exchange membrane (AEM), Fumapem® FAA-3, and a series of proton exchange membranes, Nafion®. The HMT-PMBI membrane is found to possess higher water permeabilities than Fumapem® FAA-3 and comparable permeability than Nafion (H+). By measuring water permeation through membranes of different thicknesses, we are able to decouple, for the first time, internal and interfacial water permeation resistances through anion exchange membranes. Permeation resistances on liquid/membrane interface is found to be negligible compared to that for vapor/membrane for both series of AEMs. Correspondingly, the resistance of liquid water permeation is found to be one order of magnitude smaller compared to that of vapor water permeation. HMT-PMBI possesses larger effective internal water permeation coefficient than both Fumapem® FAA-3 and Nafion® membranes (60 and 18% larger, respectively). In contrast, the effective interfacial permeation coefficient of HMT-PMBI is found to be similar to Fumapem® (±5%) but smaller than Nafion®(H+) (by 14%).

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.

Chemical modification of Nafion membranes by protic ionic liquids: the key role of ionomer-cation interactions.

PubMed

Lu, Fei; Gao, Xinpei; Xie, Shuting; Sun, Nan; Zheng, Liqiang

2014-10-21

Chemically modified Nafion composite membranes were successfully fabricated using five kinds of protic ionic liquids (PILs) with different cations, 1-butylammonium methanesulfonate (BA-MS), tributylammonium methanesulfonate (TBA-MS), 2,4,6-trimethylphenylammonium methanesulfonate (TMA-MS), butane-1,4-diammonium methanesulfonate (BDA-MS), and N-(2-aminoethyl)ethane-1,2-diammonium methanesulfonate (DETA-MS). The PIL incorporated Nafion composite membranes were characterized by impedance spectroscopy, small-angle X-ray scattering (SAXS), dynamic-mechanical analysis (DMA) and thermogravimetric analysis (TGA). In general, the Nafion/PIL composite membranes exhibit a significant increase in the ionic conductivities than Nafion under anhydrous conditions. The interactions between the Nafion ionomer and different geometric cations of PILs were also discussed by the comparison of nanostructures, dynamic-mechanical properties and thermal stabilities of the Nafion/PIL composite membranes.

Antisolvent membrane crystallization of pharmaceutical compounds.

PubMed

Di Profio, Gianluca; Stabile, Carmen; Caridi, Antonella; Curcio, Efrem; Drioli, Enrico

2009-12-01

This article describes a modification of the conventional membrane crystallization technique in which a membrane is used to dose the solvent/antisolvent composition to generate supersaturation and induce crystallization in a drug solution. Two operative configurations are proposed: (a) solvent/antisolvent demixing crystallization, where the solvent is removed in at higher flow rate than the antisolvent so that phase inversion promotes supersaturation and (b) antisolvent addition, in which the antisolvent is dosed into the crystallizing drug solution. In both cases, solvent/antisolvent migration occurs in vapor phase and it is controlled by the porous membrane structure, acting on the operative process parameters. This mechanism is different than that observed when forcing the liquid phases through the pores and the more finely controllable supersaturated environment would generate crystals with the desired characteristics. Two organic molecules of relevant industrial implication, like paracetamol and glycine, were used to test the new systems. Experiments demonstrated that, by using antisolvent membrane crystallization in both configurations, accurate control of solution composition at the crystallization point has been achieved with effects on crystals morphology. 2009 Wiley-Liss, Inc. and the American Pharmacists Association

Mechanical characterization of capsule properties using abrupt-step channels

NASA Astrophysics Data System (ADS)

Salsac, Anne-Virginie; Le Goff, Anne; Kaoui, Badr; Barthè-Biesel, Dominique; Biomechanics; Bioengineering Lab Team

2017-11-01

Capsules consisting of a liquid droplet enclosed by a thin polymerized membrane are commonly encountered in nature (cells) or in industrial process (pharmaceutical, cosmetic or food products). The mechanical properties of the capsule wall are essential to guarantee the particle integrity and release of the internal contents when and where necessary. The difficulty is to assess the mechanical properties of the thin membrane. We will show how abrupt-step channels can be used to identify the membrane viscoelastic properties and point of rupture. This can be achieved by using a channel presenting a step change in cross-section and inverting the direction of the flow of the capsule suspension within the tube. To deduce information on the viscoelasticity, we will exploit the relaxation of the capsules as they flow through the expansion. To study membrane rupture, we will instead invert the channel, block the capsules at the neck of the constriction and determine the pressure difference needed for breakup. All the experiments will be conducted on initially spherical capsules with a thin cross-linked protein membrane for a proof of concept.

Microspectroscopic investigation of the membrane clogging during the sterile filtration of the growth media for mammalian cell culture.

PubMed

Cao, Xiaolin; Loussaert, James A; Wen, Zai-qing

2016-02-05

Growth media for mammalian cell culture are very complex mixtures of several dozens of ingredients, and thus the preparation of qualified media is critical to viable cell density and final product titers. For liquid media prepared from powdered ingredients, sterile filtration is required prior to use to safeguard the cell culture process. Recently one batch of our prepared media failed to pass through the sterile filtration due to the membrane clogging. In this study, we report the root cause analysis of the failed sterile filtration based on the investigations of both the fouling media and the clogged membranes with multiple microspectroscopic techniques. Cellular particles or fragments were identified in the fouling media and on the surfaces of the clogged membranes, which were presumably introduced to the media from the bacterial contamination. This study demonstrated that microspectroscopic techniques may be used to rapidly identify both microbial particles and inorganic precipitates in the cell culture media. Copyright © 2015 Elsevier B.V. All rights reserved.

Porous polycarbene-bearing membrane actuator for ultrasensitive weak-acid detection and real-time chemical reaction monitoring.

PubMed

Sun, Jian-Ke; Zhang, Weiyi; Guterman, Ryan; Lin, Hui-Juan; Yuan, Jiayin

2018-04-30

Soft actuators with integration of ultrasensitivity and capability of simultaneous interaction with multiple stimuli through an entire event ask for a high level of structure complexity, adaptability, and/or multi-responsiveness, which is a great challenge. Here, we develop a porous polycarbene-bearing membrane actuator built up from ionic complexation between a poly(ionic liquid) and trimesic acid (TA). The actuator features two concurrent structure gradients, i.e., an electrostatic complexation (EC) degree and a density distribution of a carbene-NH 3 adduct (CNA) along the membrane cross-section. The membrane actuator performs the highest sensitivity among the state-of-the-art soft proton actuators toward acetic acid at 10 -6  mol L -1 (M) level in aqueous media. Through competing actuation of the two gradients, it is capable of monitoring an entire process of proton-involved chemical reactions that comprise multiple stimuli and operational steps. The present achievement constitutes a significant step toward real-life application of soft actuators in chemical sensing and reaction technology.

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids.

PubMed

Lin, Junhong; Liu, Yang; Zhang, Q M

2011-01-21

The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (σ>5×10(-2) mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for σ below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed.

Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids

PubMed Central

Lin, Junhong; Liu, Yang; Zhang, Q. M.

2011-01-01

The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (σ>5×10−2 mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for σ below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed. PMID:21339839

Membrane-less variable focus liquid lens with manual actuation

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Comparative study of bending characteristics of ionic polymer actuators containing ionic liquids for modeling actuation

NASA Astrophysics Data System (ADS)

Kikuchi, Kunitomo; Sakamoto, Takumi; Tsuchitani, Shigeki; Asaka, Kinji

2011-04-01

Ionic polymer metal composites (IPMCs) that can operate in air have recently been developed by incorporating an ionic liquid in ionic polymers. To understand transduction in these composites, it is important to determine the role of the ionic liquid in the ionic polymer (Nafion®), to identify the counter cation, and to investigate the interaction of IPMCs with water vapor in the air. We used Fourier-transform infrared spectroscopy to analyze three Nafion® membranes, which were soaked in mixtures of water and an ionic liquid (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIBF4), 1-buthyl-3-methyl-imidazolium tetrafluoroborate (BMIBF4), and 1-buthyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6)). The results demonstrate that only cations (EMI+ and BMI+) in the ionic liquids are taken into the Nafion® membranes as counter ions and that the water content of the membranes in air is less than ˜4% that of Nafion® swollen with water. Based on the experimental results, a transduction model is proposed for an IPMC with an ionic liquid. In this model, bending is caused by local swelling due to the volume effect of the bulky counter cations. This model can explain 30-50% of the experimentally observed bending curvature.

Electrochemical ion transfer across liquid/liquid interfaces confined within solid-state micropore arrays--simulations and experiments.

PubMed

Strutwolf, Jörg; Scanlon, Micheál D; Arrigan, Damien W M

2009-01-01

Miniaturised liquid/liquid interfaces provide benefits for bioanalytical detection with electrochemical methods. In this work, microporous silicon membranes which can be used for interface miniaturisation were characterized by simulations and experiments. The microporous membranes possessed hexagonal arrays of pores with radii between 10 and 25 microm, a pore depth of 100 microm and pore centre-to-centre separations between 99 and 986 microm. Cyclic voltammetry was used to monitor ion transfer across arrays of micro-interfaces between two immiscible electrolyte solutions (microITIES) formed at these membranes, with the organic phase present as an organogel. The results were compared to computational simulations taking into account mass transport by diffusion and encompassing diffusion to recessed interfaces and overlapped diffusion zones. The simulation and experimental data were both consistent with the situation where the location of the liquid/liquid (l/l) interface was on the aqueous side of the silicon membrane and the pores were filled with the organic phase. While the current for the forward potential scan (transfer of the ion from the aqueous phase to the organic phase) was strongly dependent on the location of the l/l interface, the current peak during the reverse scan (transfer of the ion from the organic phase to the aqueous phase) was influenced by the ratio of the transferring ion's diffusion coefficients in both phases. The diffusion coefficient of the transferring ion in the gelified organic phase was ca. nine times smaller than in the aqueous phase. Asymmetric cyclic voltammogram shapes were caused by the combined effect of non-symmetrical diffusion (spherical and linear) and by the inequality of the diffusion coefficient in both phases. Overlapping diffusion zones were responsible for the observation of current peaks instead of steady-state currents during the forward scan. The characterisation of the diffusion behaviour is an important requirement for application of these silicon membranes in electroanalytical chemistry.

Raft-Like Membrane Domains in Pathogenic Microorganisms

PubMed Central

Farnoud, Amir M.; Toledo, Alvaro M.; Konopka, James B.; Del Poeta, Maurizio; London, Erwin

2016-01-01

The lipid bilayer of the plasma membrane is thought to be compartmentalized by the presence of lipid-protein microdomains. In eukaryotic cells, microdomains composed of sterols and sphingolipids packed in a liquid-ordered state, commonly known as lipid rafts, are believed to exist. While less studied in bacterial cells, reports on the presence of sterol or protein-mediated microdomains in bacterial cell membranes are also appearing with increasing frequency. Recent efforts have been focused on addressing the biophysical and biochemical properties of lipid rafts. However, most studies have been focused on synthetic membranes, mammalian cells, and/or model, non-pathogenic microorganisms. Much less is known about microdomains in the plasma membrane of pathogenic microorganisms. This review attempts to provide an overview of the current state of knowledge of lipid rafts in pathogenic fungi and the developing field of microdomains in pathogenic bacteria. The current literature on the structure and function and of microdomains is reviewed and the potential role of microdomains in growth, pathogenesis, and drug resistance of pathogens are discussed. Better insight into the structure and function of membrane microdomains in pathogenic microorganisms might lead to a better understanding of the process of pathogenesis and development of raft-mediated approaches for new methods of therapy. PMID:26015285

Development of a preprototype thermoelectric integrated membrane evaporation subsystem for water recovery

NASA Technical Reports Server (NTRS)

Winkler, H. E.; Roebelen, G. J., Jr.

1980-01-01

A three-man urine water recovery preprototype subsystem using a new concept to provide efficient potable water recovery from waste fluids on extended duration space flights has been designed, fabricated, and tested. Low power, compactness, and gravity insensitive operation are featured in this vacuum distillation subsystem that combines a hollow fiber polysulfone membrane evaporator with a thermoelectric heat pump. Application and integration of these key elements have solved problems inherent in previous reclamation subsystem designs. The hollow fiber elements provide positive liquid/gas phase control with no moving parts other than a waste liquid recirculation pump and a product water withdrawal pump. Tubular membranes provide structural integrity, improving on previous flat sheet membrane designs. A thermoelectric heat pump provides latent energy recovery.

Contaminant Removal from Oxygen Production Systems for In Situ Resource Utilization

NASA Technical Reports Server (NTRS)

Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

2012-01-01

The In Situ Resource Utilization (ISRU) project has been developing technologies to produce oxygen from lunar regolith to provide consumables to a lunar outpost. The processes developed reduce metal oxides in the regolith to produce water, which is then electrolyzed to produce oxygen. Hydrochloic and hydrofluoric acids are byproducts of the reduction processes, as halide minerals are also reduced at oxide reduction conditions. Because of the stringent water quality requirements for electrolysis, there is a need for a contaminant removal process. The Contaminant Removal from Oxygen Production Systems (CROPS) team has been developing a separation process to remove these contaminants in the gas and liquid phase that eliminates the need for consumables. CROPS has been using Nafion, a highly water selective polymeric proton exchange membrane, to recover pure water from the contaminated solution. Membrane thickness, product stream flow rate, and acid solution temperature and concentration were varied with the goal of maximizing water permeation and acid rejection. The results show that water permeation increases with increasing solution temperature and product stream flow rate, while acid rejection increases with decreasing solution temperature and concentration. Thinner membranes allowed for higher water flux and acid rejection than thicker ones. These results were used in the development of the hardware built for the most recent Mars ISRU demonstration project.

Insights into the role of wettability in cathode catalyst layer of proton exchange membrane fuel cell; pore scale immiscible flow and transport processes

NASA Astrophysics Data System (ADS)

Fathi, H.; Raoof, A.; Mansouri, S. H.

2017-05-01

The production of liquid water in cathode catalyst layer, CCL, is a significant barrier to increase the efficiency of proton exchange membrane fuel cell. Here we present, for the first time, a direct three-dimensional pore-scale modelling to look at the complex immiscible two-phase flow in CCL. After production of the liquid water at the surface of CCL agglomerates due to the electrochemical reactions, water spatial distribution affects transport of oxygen through the CCL as well as the rate of reaction at the agglomerate surfaces. To explore the wettability effects, we apply hydrophilic and hydrophobic properties using different surface contact angles. Effective diffusivity is calculated under several water saturation levels. Results indicate larger diffusive transport values for hydrophilic domain compared to the hydrophobic media where the liquid water preferentially floods the larger pores. However, hydrophobic domain showed more available surface area and higher oxygen consumption rate at the reaction sites under various saturation levels, which is explained by the effect of wettability on pore-scale distribution of water. Hydrophobic domain, with a contact angle of 150, reveals efficient water removal where only 28% of the pore space stays saturated. This condition contributes to the enhanced available reaction surface area and oxygen diffusivity.

Post Retort, Pre Hydro-treat Upgrading of Shale Oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, John

Various oil feedstocks, including oil from oil shale, bitumen from tar sands, heavy oil, and refin- ery streams were reacted with the alkali metals lithium or sodium in the presence of hydrogen or methane at elevated temperature and pressure in a reactor. The products were liquids with sub- stantially reduced metals, sulfur and nitrogen content. The API gravity typically increased. Sodi- um was found to be more effective than lithium in effectiveness. The solids formed when sodium was utilized contained sodium sulfide which could be regenerated electrochemically back to so- dium and a sulfur product using a "Nasicon", sodium ionmore » conducting membrane. In addition, the process was found to be effective reducing total acid number (TAN) to zero, dramatically reduc- ing the asphaltene content and vacuum residual fraction in the product liquid. The process has promise as a means of eliminating sulfur oxide and carbon monoxide emissions. The process al- so opens the possibility of eliminating the coking process from upgrading schemes and upgrad- ing without using hydrogen.« less

Surface patterning of polymeric separation membranes and its influence on the filtration performance

NASA Astrophysics Data System (ADS)

Maruf, Sajjad

Polymeric membrane based separation technologies are crucial for addressing the global issues such as water purification. However, continuous operations of these processes are often hindered by fouling which increases mass transport resistance of the membrane to permeation and thus the energy cost, and eventually replacement of the membrane in the system. In comparison to other anti-fouling strategies, the use of controlled surface topography to mitigate fouling has not been realized mainly due to the lack of methods to create targeted topography on the porous membrane surface. This thesis aims to develop a new methodology to create surface-patterned polymeric separation membrane to improve their anti-fouling characteristics during filtration. First, successful fabrication of sub-micron surface patterns directly on a commercial ultrafiltration (UF) membrane surface using nanoimprint lithographic (NIL) technique was demonstrated. Comprehensive filtration studies revealed that the presence of these sub-micron surface patterns mitigates not only the onset of colloidal particle deposition, but also lowers the rate of growth of cake layer after initial deposition, in comparison with un-patterned membranes. The anti-fouling effects were also observed for model protein solutions. Staged filtration experiments, with backwash cleaning, revealed that the permeate flux of the patterned membrane after protein fouling was considerably higher than that of the pristine or un-patterned membrane. In addition to the surface-patterning of UF membranes, successful fabrication of a surface-patterned thin film composite (TFC) membrane was shown for the first time. A two-step fabrication process was carried out by (1) nanoimprinting a polyethersulfone (PES) support using NIL, and (2) forming a thin dense film atop the PES support via interfacial polymerization (IP). Fouling experiments suggest that the surface patterns alter the hydrodynamics at the membrane-feed interface, which is effective in decreasing fouling in dead end filtration system. In summary, this thesis represents the first ever fabrication of functional patterned polymeric separation membrane and systematic investigation of the influence of submicron surface patterns on pressure-driven liquid membrane separations. The results presented here will enable an effective non-chemical surface modification anti-fouling strategy, which can be directly added onto current commercial separation membrane manufacturing route.

Bioremediation and Detoxification of the Textile Wastewater with Membrane Bioreactor Using the White-rot Fungus and Reuse of Wastewater

PubMed Central

Hossain, Kaizar; Quaik, Shlrene; Ismail, Norli; Rafatullah, Mohd; Avasan, Maruthi; Shaik, Rameeja

2016-01-01

Background Application of membrane technology to wastewater treatment has expanded over the last decades due to increasingly stringent legislation, greater opportunities for water reuse/recycling processes and continuing advancement in membrane technology. Objectives In the present study, a bench-scale submerged microfiltration membrane bioreactor (MBR) was used to assess the treatment of textile wastewater. Materials and Methods The decolorization capacity of white-rot fungus coriolus versicolor was confirmed through agar plate and liquid batch studies. The temperature and pH of the reactor were controlled at 29±1°C and 4.5±2, respectively. The bioreactor was operated with an average flux of 0.05 m.d-1 (HRT=15hrs) for a month. Results Extensive growth of fungi and their attachment to the membrane led to its fouling and associated increase of the transmembrane pressure requiring a periodic withdrawal of sludge and membrane cleaning. However, stable decoloration activity (approx. 98%), BOD (40-50%), COD (50-67%) and total organic carbon (TOC) removal (>95%) was achieved using the entire system (fungi + membrane), while the contribution of the fungi culture alone for TOC removal, as indicated by the quality of the reactor supernatant, was 35-50% and 70%, respectively. Conclusions The treated wastewater quality satisfied the requirement of water quality for dyeing and finishing process excluding light coloration. Therefore, textile wastewater reclamation and reuse is a promising alternative, which can both conserve or supplement the available water resource and reduce or eliminate the environmental pollution. PMID:28959331

Proteomic analysis of corneal endothelial cell-descemet membrane tissues reveals influence of insulin dependence and disease severity in type 2 diabetes mellitus.

PubMed

Skeie, Jessica M; Aldrich, Benjamin T; Goldstein, Andrew S; Schmidt, Gregory A; Reed, Cynthia R; Greiner, Mark A

2018-01-01

The objective of this study was to characterize the proteome of the corneal endothelial cell layer and its basement membrane (Descemet membrane) in humans with various severities of type II diabetes mellitus compared to controls, and identify differentially expressed proteins across a range of diabetic disease severities that may influence corneal endothelial cell health. Endothelium-Descemet membrane complex tissues were peeled from transplant suitable donor corneas. Protein fractions were isolated from each sample and subjected to multidimensional liquid chromatography and tandem mass spectrometry. Peptide spectra were matched to the human proteome, assigned gene ontology, and grouped into protein signaling pathways unique to each of the disease states. We identified an average of 12,472 unique proteins in each of the endothelium-Descemet membrane complex tissue samples. There were 2,409 differentially expressed protein isoforms that included previously known risk factors for type II diabetes mellitus related to metabolic processes, oxidative stress, and inflammation. Gene ontology analysis demonstrated that diabetes progression has many protein footprints related to metabolic processes, binding, and catalysis. The most represented pathways involved in diabetes progression included mitochondrial dysfunction, cell-cell junction structure, and protein synthesis regulation. This proteomic dataset identifies novel corneal endothelial cell and Descemet membrane protein expression in various stages of diabetic disease. These findings give insight into the mechanisms involved in diabetes progression relevant to the corneal endothelium and its basement membrane, prioritize new pathways for therapeutic targeting, and provide insight into potential biomarkers for determining the health of this tissue.

On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

NASA Technical Reports Server (NTRS)

Colon, Guillermo

1995-01-01

The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found that the permeate flux declines rapidly during the first 5 to 8 hours, and then levels off with a diminishing rate of flux decay.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gordon, John Howard; Alvare, Javier

Alkali metals and sulfur may be recovered from alkali monosulfide and polysulfides in an electrolytic process that utilizes an electrolytic cell having an alkali ion conductive membrane. An anolyte solution includes an alkali monosulfide, an alkali polysulfide, or a mixture thereof and a solvent that dissolves elemental sulfur. A catholyte includes molten alkali metal. Applying an electric current oxidizes sulfide and polysulfide in the anolyte compartment, causes alkali metal ions to pass through the alkali ion conductive membrane to the catholyte compartment, and reduces the alkali metal ions in the catholyte compartment. Liquid sulfur separates from the anolyte solution andmore » may be recovered. The electrolytic cell is operated at a temperature where the formed alkali metal and sulfur are molten.« less