WorldWideScience

Sample records for autotrophic hollow-fiber membrane-aerated

  1. Treatment of High-Strength Nitrogen Wasetewater With a Hollow-Fiber Membrane-Aerated Biofilm Reactor: A Comprehensive Evaluation

    OpenAIRE

    Gilmore, Kevin R

    2008-01-01

    Protecting the quality and quantity of our water resources requires advanced treatment technologies capable of removing nutrients from wastewater. This research work investigated the capability of one such technology, a hollow-fiber membrane-aerated biofilm reactor (HFMBR), to achieve completely autotrophic nitrogen removal from a wastewater with high nitrogen content. Because the extent of oxygenation is a key parameter for controlling the metabolic processes that occur in a wastewate...

  2. Start-up strategies of membrane-aerated biofilm reactor (MABR) for completely autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Sun, Sheng-Peng; Pellicer i Nàcher, Carles; Terada, Akihiko;

    2009-01-01

    downside of this process stems from a long start-up period due to the slow growth rate of AnAOB. Therefore, two different start-up strategies, i.e., continuous inoculation of AnAOB and sequential batch inoculation of AOB and AnAOB, were tested in two laboratory scale membrane-aerated biofilm reactor (MABRs...

  3. Sequential Aeration of Membrane-Aerated Biofilm Reactors for High-Rate Autotrophic Nitrogen Removal: Experimental Demonstration

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Sun, Sheng-Peng; Lackner, Susanne;

    2010-01-01

    One-stage autotrophic nitrogen (N) removal, requiring the simultaneous activity of aerobic and anaerobic ammonium oxidizing bacteria (AOB and AnAOB), can be obtained in spatially redox-stratified biofilms. However, previous experience with Membrane-Aerated Biofilm Reactors (MABRs) has revealed a...... difficulty in reducing the abundance and activity of nitrite oxidizing bacteria (NOB), which drastically lowers process efficiency. Here we show how sequential aeration is an effective strategy to attain autotrophic N removal in MABRs: Two separate MABRs, which displayed limited or no N removal under......S rRNA gene confirmed that sequential aeration, even at elevated average O2 loads, stimulated the abundance of AnAOB and AOB and prevented the increase in NOB. Nitrous oxide (N2O) emissions were 100-fold lower compared to other anaerobic ammonium oxidation (Anammox)-nitritation systems. Hence, by...

  4. Microbial community stratification in Membrane-Aerated Biofilm Reactors for Completely Autotrophic Nitrogen Removal

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Ruscalleda, Maël; Terada, Akihiko;

    bacterial granules or biofilms. In this sense, completely autotrophic nitrogen removal from high ammonium strength wastewater was achieved in a Membrane-Aereated Biofilm Reactor (MABR) in a single step. Here, a biofilm containing nitrifiers (Aerobic Ammonium and Nitrite Oxidizing Bacteria, AOB and NOB......Due to the necessity of a source of nitrite, most of the processes involving Anaerobic Ammonium Oxidation (Anammox) are based on a separated two-step process with a previous partial-nitritation reactor. However, these two processes can occur simultaneously in the same reactor by taking advantage of......, respectively) and Anaerobic Ammonium Oxidizing Bacteria (AnAOB) is grown on bubbleless aeration membranes to remove ammonium. Since oxygen permeates through the membrane-biofilm interface while ammonium diffuses into the biofilm from the biofilm-liquid interface, oxygen gradients can be established across the...

  5. Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

    DEFF Research Database (Denmark)

    Gilmore, Kevin R.; Terada, Akihiko; Smets, Barth F.;

    2013-01-01

    allowed anaerobic ammonium-oxidizing bacteria (AnaerAOB) to develop and be retained for > 250 days. Daily autotrophic nitrogen removal of 1.7 g N/m(2) (75% of influent N load) was achieved at an oxygen/nitrogen surface loading ratio of 2.2, with up to 85% of the influent N proceeding through Anaer......AOB. During early nitritation, nitrogen oxide (NO(g), NO2(g), and N2O(g)) emissions comprised up to 10% of the removed influent nitrogen, but emissions disappeared after proliferation of AnaerAOB. Microbial communities were radially stratified, with aerobic ammonium-oxidizing bacteria (AerAOB) colonizing...... elimination of gaseous nitrogen oxide emissions....

  6. Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification.

    Science.gov (United States)

    Shin, Jung-Hun; Kim, Byung-Chun; Choi, Okkyoung; Kim, Hyunook; Sang, Byoung-In

    2015-10-28

    Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4(+)-N/m(3)/d and 0.10-0.21 kg NO3(-)-N/m(3)/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4(+) or NO3(-) loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs. PMID:26095385

  7. Shear-induced detachment of biofilms from hollow fiber silicone membranes

    OpenAIRE

    Huang, Z; McLamore, E. S.; Chuang, H. S; W. Zhang; Wereley, Steven; Leon, J. L. C.; Banks, M.K.

    2013-01-01

    A suite of techniques was utilized to evaluate the correlation between biofilm physiology, fluid-induced shear stress, and detachment in hollow fiber membrane aerated bioreactors. Two monoculture species biofilms were grown on silicone fibers in a hollow fiber membrane aerated bioreactors (HfMBR) to assess detachment under laminar fluid flow conditions. Both physiology (biofilm thickness and roughness) and nutrient mass transport data indicated the presence of a steady state mature biofilm af...

  8. Purification of nanoparticles by hollow fiber diafiltration

    International Nuclear Information System (INIS)

    Hollow Fiber Diafiltration (Hollow Fiber Tangential Flow Filtration) is an efficient and rapid alternative to traditional methods of nanoparticle purification such as ultracentrifugation, stirred cell filtration, dialysis or chromatography. Hollow Fiber Diafiltration can be used to purify a wide range of nanoparticles including liposomes, colloids, magnetic particles and nanotubes. Hollow Fiber Diafiltration is a membrane based method where pore size determines the retention or transmission of solution components. It is a flow process where the sample is gently circulated through a tubular membrane. With controlled replacement of the permeate or (dialysate), pure nanoparticles can be attained. Hollow Fiber Diafiltration can be directly scaled up from R and D volumes to production. By adding more membrane fibers and maintaining the operating parameters, large volumes can be processed in the same time with the same pressure, and flow dynamics as bench-scale volumes. Keywords: hollow fiber, Diafiltration, filtration, purification, tangential flow filtration.

  9. Purification of nanoparticles by hollow fiber diafiltration

    Science.gov (United States)

    Veeken, J.

    2012-09-01

    Hollow Fiber Diafiltration (Hollow Fiber Tangential Flow Filtration) is an efficient and rapid alternative to traditional methods of nanoparticle purification such as ultracentrifugation, stirred cell filtration, dialysis or chromatography. Hollow Fiber Diafiltration can be used to purify a wide range of nanoparticles including liposomes, colloids, magnetic particles and nanotubes. Hollow Fiber Diafiltration is a membrane based method where pore size determines the retention or transmission of solution components. It is a flow process where the sample is gently circulated through a tubular membrane. With controlled replacement of the permeate or (dialysate), pure nanoparticles can be attained. Hollow Fiber Diafiltration can be directly scaled up from R&D volumes to production. By adding more membrane fibers and maintaining the operating parameters, large volumes can be processed in the same time with the same pressure, and flow dynamics as bench-scale volumes. Keywords: hollow fiber, Diafiltration, filtration, purification, tangential flow filtration.

  10. Model-based evaluation of the role of Anammox on nitric oxide and nitrous oxide productions in membrane aerated biofilm reactor

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Smets, Barth F.; Yuan, Zhiguo;

    2013-01-01

    A multispecies one-dimensional biofilm model considering nitric oxide (NO) and nitrous oxide (N2O) productions for membrane aerated biofilm reactor (MABR) that remove nitrogen autotrophically through aerobic ammonia oxidation followed by Anammox is used to study the role of Anammox activity on th...

  11. Analysis of Process Gases and Trace Contaminants in Membrane-Aerated Gaseous Effluent Streams.

    Science.gov (United States)

    Coutts, Janelle L.; Lunn, Griffin Michael; Meyer, Caitlin E.

    2015-01-01

    In membrane-aerated biofilm reactors (MABRs), hollow fibers are used to supply oxygen to the biofilms and bulk fluid. A pressure and concentration gradient between the inner volume of the fibers and the reactor reservoir drives oxygen mass transport across the fibers toward the bulk solution, providing the fiber-adhered biofilm with oxygen. Conversely, bacterial metabolic gases from the bulk liquid, as well as from the biofilm, move opposite to the flow of oxygen, entering the hollow fiber and out of the reactor. Metabolic gases are excellent indicators of biofilm vitality, and can aid in microbial identification. Certain gases can be indicative of system perturbations and control anomalies, or potentially unwanted biological processes occurring within the reactor. In confined environments, such as those found during spaceflight, it is important to understand what compounds are being stripped from the reactor and potentially released into the crew cabin to determine the appropriateness or the requirement for additional mitigation factors. Reactor effluent gas analysis focused on samples provided from Kennedy Space Center's sub-scale MABRs, as well as Johnson Space Center's full-scale MABRs, using infrared spectroscopy and gas chromatography techniques. Process gases, such as carbon dioxide, oxygen, nitrogen, nitrogen dioxide, and nitrous oxide, were quantified to monitor reactor operations. Solid Phase Microextraction (SPME) GC-MS analysis was used to identify trace volatile compounds. Compounds of interest were subsequently quantified. Reactor supply air was examined to establish target compound baseline concentrations. Concentration levels were compared to average ISS concentration values and/or Spacecraft Maximum Allowable Concentration (SMAC) levels where appropriate. Based on a review of to-date results, current trace contaminant control systems (TCCS) currently on board the ISS should be able to handle the added load from bioreactor systems without the need

  12. Oxygen Transfer Model for a Flow-Through Hollow-Fiber Membrane Biofilm Reactor

    DEFF Research Database (Denmark)

    Gilmore, K. R.; Little, J. C.; Smets, Barth F.;

    2009-01-01

    the biofilm present, oxygen transfer efficiencies between 30 and 55% were calculated from the measured data including the outlet gas oxygen concentration, ammonia consumption stoichiometry, and oxidized nitrogen production stoichiometry, all of which were in reasonable agreement. The mechanistic model......A mechanistic oxygen transfer model was developed and applied to a flow-through hollow-fiber membrane-aerated biofilm reactor. Model results are compared to conventional clean water test results as well as performance data obtained when an actively nitrifying biofilm was present on the fibers. With...... overpredicted the oxygen transfer by a factor of 1.3 relative to the result calculated from the outlet gas oxygen concentration, which was considered the most accurate of the measured benchmarks. A mass transfer coefficient derived from the clean water testing with oxygen sensors at the membrane...

  13. Preparation of TiO2 hollow fibers using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template

    International Nuclear Information System (INIS)

    TiO2 hollow fibers were successfully prepared by using poly(vinylidene fluoride) hollow fiber microfiltration membrane as a template. The preparation procedure includes repeated impregnation of the TiO2 precursor in the pores of the polymeric membrane, and calcination to burn off the template, producing the TiO2 hollow fibers. The TiO2 hollow fibers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). TiO2 hollow fibers with other structures, such as honeycomb monolith and spring, were also prepared by preshaping the polymeric membranes into the honeycomb structure and spring, respectively. The phase structure of the TiO2 hollow fibers could be readily adjusted by changing the calcination temperature

  14. Hollow-Fiber Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Settles, Joseph

    2013-01-01

    The hollow-fiber spacesuit water membrane evaporator (HoFi SWME) is being developed to perform the thermal control function for advanced spacesuits and spacecraft to take advantage of recent advances in micropore membrane technology in providing a robust, heat-rejection device that is less sensitive to contamination than is the sublimator. After recent contamination tests, a commercial-off-the-shelf (COTS) micro porous hollow-fiber membrane was selected for prototype development as the most suitable candidate among commercial hollow-fiber evaporator alternatives. An innovative design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was developed into a full-scale prototype for the spacesuit application. Vacuum chamber testing has been performed to characterize heat rejection as a function of inlet water temperature and water vapor back-pressure, and to show contamination resistance to the constituents expected to be found in potable water produced by the wastewater reclamation distillation processes. Other tests showed tolerance to freezing and suitability to reject heat in a Mars pressure environment. In summary, HoFi SWME is a lightweight, compact evaporator for heat rejection in the spacesuit that is robust, contamination- insensitive, freeze-tolerant, and able to reject the required heat of spacewalks in microgravity, lunar, and Martian environments. The HoFi is packaged to reject 810 W of heat through 800 hours of use in a vacuum environment, and 370 W in a Mars environment. The device also eliminates free gas and dissolved gas from the coolant loop.

  15. Americium transfer studies using hollow fiber/extractant membranes

    International Nuclear Information System (INIS)

    Americium can be removed from low acid/high nitrate feeds using hollow fiber membrane modules. Americium can be concentrated in the stripping solution. (Maximum observed concentration was a factor of 3.1). Accurel hollow fibers are less prone to leakage problems

  16. Back-washing method for hollow fiber membrane filter

    International Nuclear Information System (INIS)

    For processing condensates in a nuclear reactor, when the amount of the suspended matters contained in the condensates is increased upon filtering them through hollow fiber membrane, the hollow fiber membranes per se can no more be generated and have to be discarded. In view of the above, filtering operation is interrupted and air scrubbing is applied immediately for back-washing the hollow fiber membrane filters. Then, after filling water below a pipe plate and applying dome draining and dome pressurization, bumping is applied to the hollow fiber membranes. In this way, the scrubbing step is applied preferentially to the bumping step and a combination of the scrubbing and bumping step is repeated at least twice. This enables to conduct efficient back-washing and, accordingly, extend the life time of the hollow fiber membranes so that they can withstand long time use. (T.M.)

  17. Air Separation Using Hollow Fiber Membranes

    Science.gov (United States)

    Huang, Stephen E.

    2004-01-01

    The NASA Glenn Research Center in partnership with the Ohio Aerospace Institute provides internship programs for high school and college students in the areas of science, engineering, professional administrative, and other technical areas. During the summer of 2004, I worked with Dr. Clarence T. Chang at NASA Glenn Research Center s combustion branch on air separation using hollow fiber membrane technology. . In light of the accident of Trans World Airline s flight 800, FAA has mandated that a suitable solution be created to prevent the ignition of fuel tanks in aircrafts. In order for any type of fuel to ignite, three important things are needed: fuel vapor, oxygen, and an energy source. Two different ways to make fuel tanks less likely to ignite are reformulating the fuel to obtain a lower vapor pressure for the fuel and or using an On Board Inert Gas Generating System (OBIGGS) to inert the Central Wing Tank. goal is to accomplish the mission, which means that the Air Separation Module (ASM) tends to be bulky and heavy. The primary goal for commercial aviation companies is to transport as much as they can with the least amount of cost and fuel per person, therefore the ASM must be compact and light as possible. The plan is to take bleed air from the aircraft s engines to pass air through a filter first to remove particulates and then pass the air through the ASM containing hollow fiber membranes. In the lab, there will be a heating element provided to simulate the temperature of the bleed air that will be entering the ASM and analysis of the separated air will be analyzed by a Gas Chromatograph/Mass Spectrometer (GC/MS). The GUMS will separate the different compounds in the exit streams of the ASM and provide information on the performance of hollow fiber membranes. Hopefully I can develop ways to improve efficiency of the ASM. different types of jet fuel were analyzed and data was well represented on SAE Paper 982485. Data consisted of the concentrations of over

  18. Hollow fiber membranes and methods for forming same

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Dhaval Ajit; McCloskey, Patrick Joseph; Howson, Paul Edward; Narang, Kristi Jean; Koros, William

    2016-03-22

    The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

  19. Polyazole hollow fiber membranes for direct contact membrane distillation

    KAUST Repository

    Maab, Husnul

    2013-08-07

    Porous hollow fiber membranes were fabricated from fluorinated polyoxadiazole and polytriazole by a dry-wet spinning method for application in desalination of Red Sea water by direct contact membrane distillation (DCMD). The data were compared with commercially available hollow fiber MD membranes prepared from poly(vinylidene fluoride). The membranes were characterized by electron microscopy, liquid entry pressure (LEP), and pore diameter measurements. Finally, the hollow fiber membranes were tested for DCMD. Salt selectivity as high as 99.95% and water fluxes as high as 35 and 41 L m -2 h-1 were demonstrated, respectively, for polyoxadiazole and polytriazole hollow fiber membranes, operating at 80 C feed temperature and 20 C permeate. © 2013 American Chemical Society.

  20. Preparation of Polyvinylidene Fluoride (PVDF Hollow Fiber Hemodialysis Membranes

    Directory of Open Access Journals (Sweden)

    Qinglei Zhang

    2014-02-01

    Full Text Available In this study, the polyvinylidene fluoride (PVDF hollow fiber hemodialysis membranes were prepared by non-solvent induced phase separation (NIPS. The influences of PVDF membrane thickness and polyethylene glycol (PEG content on membrane morphologies, pore size, mechanical and permeable performance were investigated. It was found that membrane thickness and PEG content affected both the structure and performance of hollow fiber membranes. The tensile strength and rejection of bovine serum albumin (BSA increased with increasing membrane thickness, while the Ultrafiltration flux (UF flux of pure water was the opposite. The tensile strength, porosity and rejection of BSA increased with increasing PEG content within a certain range. Compared with commercial F60S membrane, the PVDF hollow fiber membrane showed higher mechanical and permeable performance. It was proven that PVDF material had better hydrophilicity and lower BSA adsorption, which was more suitable for hemodialysis. All the results indicate that PVDF hollow fiber membrane is promising as a hemodialysis membrane.

  1. Preparation of Polyvinylidene Fluoride (PVDF) Hollow Fiber Hemodialysis Membranes.

    Science.gov (United States)

    Zhang, Qinglei; Lu, Xiaolong; Zhao, Lihua

    2014-01-01

    In this study, the polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were prepared by non-solvent induced phase separation (NIPS). The influences of PVDF membrane thickness and polyethylene glycol (PEG) content on membrane morphologies, pore size, mechanical and permeable performance were investigated. It was found that membrane thickness and PEG content affected both the structure and performance of hollow fiber membranes. The tensile strength and rejection of bovine serum albumin (BSA) increased with increasing membrane thickness, while the Ultrafiltration flux (UF) flux of pure water was the opposite. The tensile strength, porosity and rejection of BSA increased with increasing PEG content within a certain range. Compared with commercial F60S membrane, the PVDF hollow fiber membrane showed higher mechanical and permeable performance. It was proven that PVDF material had better hydrophilicity and lower BSA adsorption, which was more suitable for hemodialysis. All the results indicate that PVDF hollow fiber membrane is promising as a hemodialysis membrane. PMID:24957122

  2. Hollow fiber membrane systems for advanced life support systems

    Science.gov (United States)

    Roebelen, G. J., Jr.; Lysaght, M. J.

    1976-01-01

    The practicability of utilizing hollow fiber membranes in vehicular and portable life support system applications is described. A preliminary screening of potential advanced life support applications resulted in the selection of five applications for feasibility study and testing. As a result of the feasibility study and testing, three applications, heat rejection, deaeration, and bacteria filtration, were chosen for breadboard development testing; breadboard hardware was manufactured and tested, and the physical properties of the hollow fiber membrane assemblies are characterized.

  3. Preparation of Polyvinylidene Fluoride (PVDF) Hollow Fiber Hemodialysis Membranes

    OpenAIRE

    Qinglei Zhang; Xiaolong Lu; Lihua Zhao

    2014-01-01

    In this study, the polyvinylidene fluoride (PVDF) hollow fiber hemodialysis membranes were prepared by non-solvent induced phase separation (NIPS). The influences of PVDF membrane thickness and polyethylene glycol (PEG) content on membrane morphologies, pore size, mechanical and permeable performance were investigated. It was found that membrane thickness and PEG content affected both the structure and performance of hollow fiber membranes. The tensile strength and rejection of bovine serum a...

  4. Experience and economic evaluation of backwashable hollow fiber filter

    International Nuclear Information System (INIS)

    In the initial applications of filtration systems to nuclear power plants, filtration has been provided by precoat and cartridge type filters as required. These filters provide good effluent but generate a great amount of burial volume. This makes the cost of diatomaceous earth or other precoat media and spent cartridge filter burial costs not as significant. Today, however, and in particular in the future with present burial sites being restricted and the compact surcharge being imposed, volume reduction is a first priority in all considerations of waste handling. This paper discusses the hollow fiber filter process development, test data, results and economics of the 5 gpm hollow fiber filter system as tested on low TDS and high TDS solids from a secondary PWR. With this incineratible hollow fiber filter, the volume of drummed material is limited to the captured crud only. The effluent quality from these tests exceeded the NPDES discharge permit requirements

  5. Fabrication of Polyacrylonitrile Hollow Fiber Membranes from Ionic Liquid Solutions

    KAUST Repository

    Kim, Dooli

    2015-10-08

    The interest in green processes and products has increased to reduce the negative impact of many industrial processes to the environment. Solvents, which play a crucial role in the fabrication of membranes, need to be replaced by sustainable and less toxic solvent alternatives for commonly used polymers. The purpose of this study is the fabrication of greener hollow fiber membranes based on polyacrylonitrile (PAN), substituting dimethylformamide (DMF) by less toxic mixtures of ionic liquids (IL) and dimethylsulfoxide (DMSO). A thermodynamic analysis was conducted, estimating the Gibbs free energy of mixing to find the most convenient solution compositions. Hollow fiber membranes were manufactured and optimized. As a result, a uniform pattern and high porosity were observed in the inner surface of the membranes prepared from the ionic liquid solutions. The membranes were coated with a polyamide layer by interfacial polymerization the hollow fiber membranes were applied in forward osmosis experiments by using sucrose solutions as draw solution.

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

    Science.gov (United States)

    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

  7. Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

    Directory of Open Access Journals (Sweden)

    Matthew Zeh

    2016-03-01

    Full Text Available 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(trifluoromethylsulfonylimide ([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.

  8. Fabrication of a Polyamide/Polysulfone Hollow Fiber Composite Membrane

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-feng; LIANG Chang-liang; DU Qi-yun; XIAO Chang-fa; YU Hong-liang

    2005-01-01

    With microporous polysulfone hollow fiber as the substrate,a polypiperazine amide nanofiltration composite membrane was prepared by interfacial polymerization in trimesoyl hexane solution as oil phase and piperazine aqueous solution as water phase. The conditions of the preparation, such as concentrations of monomer solutions, reaction time and temperature, annealing treatment, etc., were investigated.The hollow fiber composite herewith obtained showed high performance with water fluxes over 40 L · m-2 · hr-1 and MgSO4 rejection of 93% under a pressure of 0. 40 MPa.

  9. FOST 2 Upgrade with Hollow-Fiber CTA FO Module and Generation of Osmotic Agent for Microorganism Growth Studies

    Science.gov (United States)

    Parodi, Jurek; Mangado, Jaione Romero; Stefanson, Ofir; Flynn, Michael; Shaw, Hali; Beeler, David

    2016-01-01

    FOST 2 is an integrated membrane system that incorporates a forward osmosis subsystem and a reverse osmosis subsystem working in series. It has been designed as a post treatment system to process the effluent from the Membrane Aerated Biological Reactor developed at NASA Johnson Space Center and Texas Tech University. Its function is to remove dissolved solids residual such as ammonia and suspended solids, as well as to provide a physical barrier to microbial and viral contamination. A tubular CTA membrane module from HTI and a flat-sheet lipid-base membrane module from Porifera were integrated and tested on FOST 2 in the past, using both a bioreactor's effluent and greywater as the feed solution. This paper documents the performance of FOST 2 after its upgrade with a hollow-fiber CTA membrane module from Toyobo, treating real black-water to generate the osmotic agent solution necessary to conduct growth studies of genetically engineered microorganism for the Synthetic Biological Membrane project.

  10. Evolution of radiation resistant hollow fibers membranes for nuclear

    International Nuclear Information System (INIS)

    We have evaluated hollow fiber supported liquid membrane (HFSLM) technique for the separation of actinides, fission products and other valuables from the nuclear waste solutions. In this technique, ligand responsible for separation of metal ion is held in tiny pores of membrane. Any drastic change as a consequence of irradiation, like change in pore size, change in hydrophobicity of polymeric material can be fatal for separation process as it may lead dislodging of carrier ligands from the pores. It was therefore needed to study the irradiation stability of hollow fibers. We have earlier showed that polypropylene fibers were stable up to 500 radiation dose and we therefore need to look into other options. In the present work, hollow fiber membranes made from polyether ether ketone (PEEK), polysulphone (PS). Polymers were evaluated for their radiation stability after exposing to varying absorbed dose of gamma radiation. The hollow fibers were irradiated to 100 KGy, 200 KGy, 500 KGy and 1000 KGy and its changes in hydrophobicity were measured using contact angle measurement studies

  11. Hollow-fiber H2/O2 fuel cell

    Science.gov (United States)

    Ingham, J. D.; Lawson, D. D.

    1977-01-01

    Dual-membrane hollow-fiber electrode increases reliability and lowers costs. Leakage of fuel or oxidizer through fiber does not result in failure; excess product water migrates into electrolyte where it is removed by evaporation or distillation; constant exposure of fiber to electrolyte eliminates problems of drying and consequent failure; reference electrode monitors current collectors and overall cell performance.

  12. Preparation and characterization of alumina hollow fiber membranes

    Institute of Scientific and Technical Information of China (English)

    Tao WANG; Yuzhong ZHANG; Guangfen LI; Hong LI

    2009-01-01

    With the rapid development of membrane technology in water treatment, there is a growing demand for membrane products with high performance. The inorganic hollow fiber membranes are of great interest due to their high resistance to abrasion, chemical/thermal degradation, and higher surface area/volume ratio therefore they can be utilized in the fields of water treatment. In this study, the alumina (Al2O3) hollow fiber membranes were prepared by a combined phase-inversion and sintering method. The organic binder solution (dope) containing suspended Al2O3 powders was spun to a hollow fiber precursor, which was then sintered at elevated tempera-tures in order to obtain the Al2O3 hollow fiber membrane. The dope solution consisted ofpolyethersulfone (PES), N-methyl-2-pyrrolidone (NMP) and polyvinylpyrrolidone (PVP), which were used as polymer binder, solvent and additive, respectively. The prepared Al2O3 hollow fiber membranes were characterized by a scanning electron microscope (SEM) and thermal gravimetric analysis (TG). The effects of the sintering temperature and Al2O3/PES ratios on the morphological structure, pure water flux, pore size and porosity of the membranes were also investigated extensively. The results showed that the pure water flux, maximum pore size and porosity of the prepared membranes decreased with the increase in Al2O3/PES ratios and sintering temperature. When the Al2O3/PES ratio reached 9, the pure water flux and maximum pore size were at 2547L/m2·h and 1.4μm, respectively. Under 1600℃ of sintering temperature, the pure water flux and maximum pore size reached 2398 L/(m2·h) and 2.3 μm, respectively. The results showed that the alumina hollow fiber membranes we prepared were suitable for the microfiltration process. The morphology investigation also revealed that the prepared Al2O3 hollow fiber membrane retained its'asymmetric structure even after the sintering process.

  13. Block copolymer/homopolymer dual-layer hollow fiber membranes

    KAUST Repository

    Hilke, Roland

    2014-12-01

    We manufactured the first time block copolymer dual-layer hollow fiber membranes and dual layer flat sheet membranes manufactured by double solution casting and phase inversion in water. The support porous layer was based on polystyrene and the selective layer with isopores was formed by micelle assembly of polystyrene-. b-poly-4-vinyl pyridine. The dual layers had an excellent interfacial adhesion and pore interconnectivity. The dual membranes showed pH response behavior like single layer block copolymer membranes with a low flux for pH values less than 3, a fast increase between pH4 and pH6 and a constant high flux level for pH values above 7. The dry/wet spinning process was optimized to produce dual layer hollow fiber membranes with polystyrene internal support layer and a shell block copolymer selective layer.

  14. Research on polyvinylidene fluoride (PVDF) hollow-fiber hemodialyzer.

    Science.gov (United States)

    Zhang, Qinglei; Lu, Xiaolong; Zhao, Lihua; Liu, Juanjuan; Wu, Chunfeng

    2016-06-01

    In this study, polyvinylidene fluoride (PVDF) hollow-fiber hemodialysis membranes were prepared by non-solvent-induced phase separation. The PVDF hollow-fiber hemodialyzers were prepared by centrifugal casting. The results showed that the PVDF membrane had better mechanical and separation properties when the membrane wall thickness was 40 μm and the N,N-dimethylacetamide in the core was 70 Vol%. Compared with commercial polysulfone hemodialysis membrane (Fresenius F60S membrane), the PVDF membrane had better mechanical property and ultrafiltration (UF) flux of pure water. The PVDF dialyzer's removal efficiency for middle molecules was proven to be much higher than that of the F60S dialyzer. The UF coefficient of a high-flux PVDF dialyzer is 62.6 ml/h/mm Hg, whereas F60S is 42.5 ml/h/mm Hg, which can promote clearance for middle molecules. PMID:25781663

  15. Insoluble polyelectrolyte and ion-exchange hollow fiber impregnated therewith

    Science.gov (United States)

    Rembaum, A. (Inventor)

    1977-01-01

    The number of quaternary sites and ion exchange capacity of a polyquaternary, cross linked, insoluble copolymer of a vinyl pyridine and a dihalo organic compound is increased by about 15-35% by reaction of the polymer with an amine followed by quaternization, if required. The polymer forms spontaneously in the presence of a substrate such as within the pores of a hollow fiber. The improved resin impregnated fiber may be utilized to remove ions from waste or process steams.

  16. Transport of strontium cation through hollow fiber supported liquid membranes

    International Nuclear Information System (INIS)

    Transport of strontium through supported hollow fiber dichlorobenzene liquid membranes has been studied. The possible mechanism of strontium transport with 18-crown-6 ether as a carrier and picrate as co-counter-ion as well as the construction of a pertraction device with on-line radiometric detection of strontium using 85Sr tracer is described. Preliminary results of strontium pertraction in a recycling and one-pass mode with different concentrations of crown are shown. (author) 11 refs.; 5 figs

  17. Sandwich-structured hollow fiber membranes for osmotic power generation

    KAUST Repository

    Fu, Feng Jiang

    2015-11-01

    In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

  18. Application of microscopy technology in mathematical modeling of hollow fiber membrane system

    Science.gov (United States)

    Lock, S. S. M.; Lau, K. K.; Tan, E. K.; Shariff, A. M.; Mei, Irene Lock Sow

    2015-07-01

    Mathematical modeling becomes an indispensable tool in the design process of membrane system by predicting the required module specification and membrane characteristic that are optimum according to various operating conditions. However, challenges are often encountered in determining the effective separation area for mathematical modeling of the hollow fiber membrane system, which are associated with many fine hollow fibers. In this work, the microscopy technology has been adapted to determine the specification of the hollow fiber and packing fraction of the membrane system, before being applied alongside numerical solution to describe the separation performance of a countercurrent hollow fiber membrane system. The accuracy of the methodology has been validated through experimental work. The promising result enables further application of the methodology in industrial scale hollow fiber membrane module design with approximately ten to hundreds of thousands of extremely fine hollow fibers.

  19. Biomimetic Branched Hollow Fibers Templated by Self-assembled Fibrous Polyvinylpyrrolidone (PVP) Structures in Aqueous Solution

    OpenAIRE

    Qiu, Penghe; Mao, Chuanbin

    2010-01-01

    Branched hollow fibers are common in nature, but to form artificial fibers with a similar branched hollow structure is still a challenge. We discovered that polyvinylpyrrolidone (PVP) could self-assemble into branched hollow fibers in an aqueous solution after aging the PVP solution for about two weeks. Based on this finding, we demonstrated two approaches by which the self-assembly of PVP into branched hollow fibers could be exploited to template the formation of branched hollow inorganic fi...

  20. A Design of Composite Hollow Fiber Membranes with Tunable Performance and Reinforced Mechanical Strength

    OpenAIRE

    Zhang, Rui-Xin; Liu, Tianyin; Braeken, Leen; Liu, Zaihao; Wang, Xiao-lin; Van der Bruggen, Bart

    2015-01-01

    A new design of hollow fiber membranes with high mechanical strength, great surface area per volume ratio and tunable filtration performance is presented. This newly developed hollow fiber membrane was produced by an intensified production process, in which the processes of thermally induced phase separation (TIPS), non-solvent induced phase separation (NIPS), and interfacial polymerization (IP) were combined. PVDF (polyvinylidene difluoride) hollow fiber membranes (produced by TIPS) were use...

  1. Process for fabricating PBI hollow fiber asymmetric membranes for gas separation and liquid separation

    Energy Technology Data Exchange (ETDEWEB)

    Jayaweera, Indira; Krishnan, Gopala N.; Sanjurjo, Angel; Jayaweera, Palitha; Bhamidi, Srinivas

    2016-04-26

    The invention provides methods for preparing an asymmetric hollow fiber, the asymmetric hollow fibers prepared by such methods, and uses of the asymmetric hollow fibers. One method involves passing a polymeric solution through an outer annular orifice of a tube-in-orifice spinneret, passing a bore fluid though an inner tube of the spinneret, dropping the polymeric solution and bore fluid through an atmosphere over a dropping distance, and quenching the polymeric solution and bore fluid in a bath to form an asymmetric hollow fiber.

  2. Development of Hollow Fiber Carbon Membranes for CO2 Separation

    OpenAIRE

    He, Xuezhong

    2011-01-01

    CO2 capture from flue gases by membrane technology in post combustion power plants could be used for the reducing of CO2 emissions. Previous work has demonstrated that the carbon membrane can achieve a high separation performance with respect to high CO2 permeability and selectivity over the other gases, such as N2 and O2. The focus of the current work was to find a low-cost precursor and develop a simple process for the preparation of high performance hollow fiber carbon membranes (HFCMs) fo...

  3. Hydrometallurgical minor actinide separation in hollow fiber modules

    International Nuclear Information System (INIS)

    Hollow fiber modules (HFM) were used as phase contacting devices for hydrometallurgical minor actinide separation in the Partitioning and Transmutation context. Two single-HFM setups, one using commercially available HFM, the other one using miniature HFM, have been developed and manufactured. Several very successful DIAMEX and SANEX once-through tests were performed. The major advantage of the new miniature HFM is their size drastically reducing chemicals consumption: only several 10 mL of feed phases are required for a test. (authors)

  4. Modeling hollow fiber membrane separations using Voronoi tessellations

    International Nuclear Information System (INIS)

    Hollow fiber membrane modules have their filaments randomly packed in the shell. The maldistribution of flow on the shell side leads to different mass transfer driving forces on the individual fibers. This makes the correct sizing of HFM contactors for process applications uncertain. By use of the method of Voronoi tessellations each fiber can be treated individually and the results summed. This puts us one step closer to an a priori design algorithm. The goal of this work is to develop a self-contained design procedure that will allow chemical process engineers to correctly predict the performance of the unit without the use of totally ad hoc methods

  5. High performance micro-engineered hollow fiber membranes by smart spinneret design

    NARCIS (Netherlands)

    Nijdam, W.; Jong, de J.; Rijn, van C.J.M.; Visser, T.; Versteeg, L.A.M.; Kapantaidakis, G.; Koops, G.H.; Wessling, M.

    2005-01-01

    Can hollow fiber membranes be produced in other geometries than circular? If so, are membrane properties maintained and what could be the possible benefits of other geometries? This article gives answers and describes the fabrication of micro-structured hollow fiber membranes using micro-fabricated

  6. Synthesis of polypiperazine-amide thin-film membrane on PPESK hollow fiber UF membrane

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new interfacial polymerization (IP) procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber ultrafiltration (UF) membrane. A hollow fiber composite membrane with good performance was prepared and studied by FT-IR and scanning electron microscopy.

  7. A Trade Study of Two Membrane-Aerated Biological Water Processors

    Science.gov (United States)

    Allada, Ram; Lange, Kevin; Vega. Leticia; Roberts, Michael S.; Jackson, Andrew; Anderson, Molly; Pickering, Karen

    2011-01-01

    Biologically based systems are under evaluation as primary water processors for next generation life support systems due to their low power requirements and their inherent regenerative nature. This paper will summarize the results of two recent studies involving membrane aerated biological water processors and present results of a trade study comparing the two systems with regards to waste stream composition, nutrient loading and system design. Results of optimal configurations will be presented.

  8. Dual layer hollow fiber sorbents for trace H2S removal from gas streams

    KAUST Repository

    Bhandari, Dhaval A.

    2013-05-01

    Hollow fiber sorbents are pseudo monolithic materials with potential use in various adsorption based applications. Dual layer hollow fiber sorbents have the potential to allow thermal regeneration without direct contact of the regeneration fluid with the sorbent particles. This paper considers the application of dual layer hollow fiber sorbents for a case involving trace amounts of H2S removal from a simulated gas stream and offers a comparison with single layer hollow fiber sorbents. The effect of spin dope composition and core layer zeolite loading on the gas flux, H2S transient sorption capacity and pore structure are also studied. This work can be used as a guide to develop and optimize dual layer hollow fiber sorbent properties beyond the specific example considered here. © 2013 Elsevier Ltd.

  9. Hollow-fiber enzyme reactor operating under nonisothermal conditions.

    Science.gov (United States)

    Diano, Nadia; Grano, Valentina; Rossi, Sergio; Bencivenga, Umberto; Portaccio, Marianna; Amato, Umberto; Carfora, Francesca; Lepore, Maria; Gaeta, Francesco Saverio; Mita, Damiano Gustavo

    2004-01-01

    A hollow-fiber enzyme reactor, operating under isothermal and nonisothermal conditions, was built employing a polypropylene hollow fiber onto which beta-galactosidase was immobilized. Hexamethylenediamine and glutaraldehyde were used as spacer and coupling agent, respectively. Glucose production was studied as a function of temperature, substrate concentration, and size of the transmembrane temperature gradient. The actual average temperature differences across the polypropylene fiber, to which reference was done to evaluate the effect of the nonisothermal conditions, were calculated by means of a mathematical approach, which made it possible to know, using computer simulation, the radial and axial temperature profiles inside the bioreactor and across the membrane. Percent activity increases, proportional to the size of the temperature gradients, were found when the enzyme activities under nonisothermal conditions were compared to those measured under comparable isothermal conditions. Percent reductions of the production times, proportional to the applied temperature gradients, were also calculated. The advantage of employing nonisothermal bioreactors in biotechnological industrial process was discussed. PMID:15058990

  10. Hollow fiber clinostat for simulating microgravity in cell culture

    Science.gov (United States)

    Rhodes, Percy H. (Inventor); Miller, Teresa Y. (Inventor); Snyder, Robert S. (Inventor)

    1992-01-01

    A clinostat for simulating microgravity on cell systems carried in a fiber fixedly mounted in a rotatable culture vessel is disclosed. The clinostat is rotated horizontally along its longitudinal axis to simulate microgravity or vertically as a control response. Cells are injected into the fiber and the ends of the fiber are sealed and secured to spaced end pieces of a fiber holder assembly which consists of the end pieces, a hollow fiber, a culture vessel, and a tension spring with three alignment pins. The tension spring is positioned around the culture vessel with its ends abutting the end pieces for alignment of the spring. After the fiber is secured, the spring is decompressed to maintain tension on the fiber while it is being rotated. This assures that the fiber remains aligned along the axis of rotation. The fiber assembly is placed in the culture vessel and culture medium is added. The culture vessel is then inserted into the rotatable portion of the clinostat and subjected to rotate at selected rpms. The internal diameter of the hollow fiber determines the distance the cells are from the axis of rotation.

  11. Hollow fiber adsorbents for CO2 capture: Kinetic sorption performance

    KAUST Repository

    Lively, Ryan P.

    2011-07-01

    We describe a CO 2 capture platform based on hollow polymeric fibers with sorbent particles embedded in the porous fiber wall for post-combustion CO 2 capture. These fibers are intended for use in a rapid temperature swing adsorption (RTSA) process. The RTSA system utilizes the hollow fiber morphology by flowing cooling water on the bore-side of the fibers during sorption to prevent temperature rise associated with the sorption enthalpy. Steam or hot water is flowed through the bores during desorption to desorb CO 2 rapidly. To minimize material transfer between the bore and the fiber wall, a dense Neoprene ® lumen layer is cast on the bore-side of the fiber wall. In this paper, the key sorption step and associated kinetic resistances for the uncooled fibers are examined and evaluated for this portion of the RTSA process. Chopped fibers in a packed bed, as well as fibers assembled into a parallel flow module, have been tested in a simulated flue gas stream. Kinetic limitations in the hollow fiber modules are largely overcome by increasing the superficial gas velocity and the fiber packing in the module-indicating that film diffusion is the controlling mass transfer limitation in the fiber system. The un-cooled fiber modules lose apparent capacity as superficial velocities are increased, likely indicating non-isothermal operation, whereas the actively-cooled fibers in the packed bed maintain apparent capacity at all flowrates studied. © 2011 Elsevier B.V.

  12. Experimental and theoretical analysis of tubular membrane aeration for Mammalian cell bioreactors.

    Science.gov (United States)

    Qi, Hanshi N; Goudar, Chetan T; Michaels, James D; Henzler, Hans-Jugen; Jovanovic, Goran N; Konstantinov, Konstantin B

    2003-01-01

    A combination of experimental and theoretical approaches was used to characterize the dynamics of oxygen transfer in a membrane-aerated bioreactor. Pressure profiles along the length of the membrane at varying entrance and exit pressures were determined by actual experimental measurements, unlike most previous studies that have relied solely on theoretical descriptions of the pressure profile in the tubing. The mass transfer coefficient, k(L)a, was also determined under these conditions and was found to be essentially independent of tubing exit pressure. Measurement of the tubing pressure profile coupled with estimation of k(L)a allowed for computation of the oxygen transfer rate (OTR) along the length of the tubing. A mathematical model that incorporated friction pressure loss and losses due to tubing bending was developed to describe the pressure and hence OTR characteristics of membrane-aerated systems. The applicability of the model was verified by testing it on experimentally measured pressure data, and in all cases the model accurately described experimental data. When tubing properties are known, the mathematical model presented in this study allows for a priori estimation of OTR profiles along the length of the tubing. This information is vital for optimal design and scale-up of membrane-aerated bioreactors for mammalian cell culture. PMID:12892480

  13. Performance of different hollow fiber membranes for seawater desalination using membrane distillation

    KAUST Repository

    Francis, Lijo

    2014-08-11

    Membrane distillation requires a highly porous hydrophobic membrane with low surface energy. In this paper, we compare the direct contact membrane distillation (DCMD) performances of four different types of in-house fabricated hollow fiber membranes and two different commercially available hollow fiber membranes. Hollow fiber membranes are fabricated using wet-jet phase inversion technique and the polymeric matrices used for the fabrication are polyvinylidine fluoride (PVDF) and polyvinyl chloride (PVC). Commercial hollow fiber membrane materials are made of polytetrafluoroethylene (PTFE) and polypropylene (PP). PVDF hollow fibers showed a superior performance among all the hollow fibers tested in the DCMD process and gave a water vapor flux of 31 kg m-2h-1 at a feed and coolant inlet temperatures of 80 and 20°C, respectively. Under the same conditions, the water vapor flux observed for PP, PTFE, and PVC hollow fiber membranes are 13, 11, and 6 kg m-2h-1, respectively, with 99.99% salt rejection observed for all membranes used.

  14. STRUCTURE AND PROPERTIES OF COMPOSITE POLYURETHANE HOLLOW FIBER MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Xian-feng Li; Chang-fa Xiao

    2005-01-01

    Composite polyurethane (PU)-SiO2 hollow fiber membranes were successfully prepared via optimizing the technique of dry-jet wet spinning, and their pressure-responsibilities were confirmed by the relationships of pure water fluxtransmembrane pressure (PWF-TP) for the first time. The origin for this phenomenon was analyzed on the basis of membrane structure and material characteristics. The effects of SiO2 content on the structure and properties of membrane were investigated. The experimental results indicated that SiO2 in membrane created a great many interfacial micro-voids and played an important role in pressure-responsibility, PWF and rejection of membrane: with the increase of SiO2 content, the ability of membrane recovery weakened, PWF increased, and rejection decreased slightly.

  15. Hydraulic design optimization for hollow fiber filter system

    International Nuclear Information System (INIS)

    An analytical model has been developed to describe hydraulic characteristics of a hollow fiber membrane filter (HFF) for condensate purification in BWR power plants. Using this model, a module structure was proposed to minimize pressure drop at the beginning of HFF operation. That is, given flow rate of a module, both dimensions of the inner diameter and the length of a single fiber membrane were designed to have optimal values, giving minimum volume for the module. The mechanism of Fe ion crystallization on HFF surface which determines operation life time was clarified and a countermeasure against it was developed. Precoating of amorphous iron crud effectively inhibited crystallization. Taking account of the crystallization, a simulation code was developed to predict pressure drop trend in the course of HFF operation. (author)

  16. Modeling of Hollow-Fiber Membrane System During Ultrafiltration

    International Nuclear Information System (INIS)

    The present study aims to evaluate the performance of hollow fiber membrane module during ultrafiltration of aqueous solutions. The model is represented by a set of differential equations for permeate and residue pressure drop and volumetric flow rates in the axial direction, beside the principle equations of both solvent and solute fluxes through the membrane, while osmotic pressure was neglected in model equations. The shell and tube module type was considered where feed pass in the shell and permeate in the bore side. Tortousily factor of membrane pores in addition to concentration polarization modulus were taken into account in calculations. The model was solved numerically with the help of suitable program in both co current and countercurrent flow pattern and comparison of results were carried out

  17. Hollow fiber-optic Raman probes for small experimental animals

    Science.gov (United States)

    Katagiri, Takashi; Hattori, Yusuke; Suzuki, Toshiaki; Matsuura, Yuji; Sato, Hidetoshi

    2007-02-01

    Two types of hollow fiber-optic probes are developed to measure the in vivo Raman spectra of small animals. One is the minimized probe which is end-sealed with the micro-ball lens. The measured spectra reflect the information of the sample's sub-surface. This probe is used for the measurement of the esophagus and the stomach via an endoscope. The other probe is a confocal Raman probe which consists of a single fiber and a lens system. It is integrated into the handheld microscope. A simple and small multimodal probe is realized because the hollow optical fiber requires no optical filters. The performance of each probe is examined and the effectiveness of these probes for in vivo Raman spectroscopy is shown by animal tests.

  18. Studies on poly (vinyl chloride/silica dioxide composite hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Mei Shuo

    2016-01-01

    Full Text Available Poly (vinyl chloride/silica dioxide composite hollow fiber membranes were prepared by using the method of immersion-precipitation process. The influences of stretching ratio on the formation of the interfacial microporous of poly (vinyl chloride/silica dioxide composite hollow fiber membranes were specifically investigated by scanning electron microscope, dynamic mechanical analysis, and finite element method. Results show that with the stretching ratio increasing, numerous IFM appear on the surface of membranes. Finite element method actually reflects the dynamic change of microporous structure of poly (vinyl chloride/silica dioxide composite hollow fiber membranes.

  19. Screening and quantification of anticancer compounds in traditional Chinese medicine by hollow fiber cell fishing and hollow fiber liquid/solid-phase microextraction.

    Science.gov (United States)

    Wang, Caiyun; Hu, Shuang; Chen, Xuan; Bai, Xiaohong

    2016-05-01

    Hollow fiber cell fishing, based on HepG-2, SKOV-3, and ACHN cancer cells, and hollow fiber liquid/solid microextraction with HPLC were developed and introduced for researching the anticancer activity of Rhizoma Curcumae Longae, Radix Curcumae, and Rhizoma Curcumae. The structures of curcumin, demethoxycurcumin, and bisdemethoxycurcumin screened were identified and their contents were determined. The compound target fishing factors and cell apoptosis rates under the effect of the three medicines were determined. The binding sites (cell membrane and cell organelle) and binding target (phospholipase C) on the cell were researched. Hollow fiber liquid/solid-phase microextraction mechanism was analyzed and expounded. Before the application, cell seeding time, growth state and survival rate, compound nonspecific binding, positive and negative controls, repeatability in hollow fiber cell fishing with high-performance liquid chromatography; extraction solvent, sample pH, salt concentration, agitation speed, extraction time, temperature and sample volume in hollow fiber liquid/solid-phase microextraction with high-performance liquid chromatography were investigated. The results demonstrated that the proposed strategy is a simple and quick method to identify bioactive compounds at the cellular level as well as determine their contents (particularly trace levels of the bioactive compounds), analyze multicompound and multitarget entirety effects, and elucidate the efficacious material base in traditional medicine. PMID:26987300

  20. Kinetic aspects of hollow fiber liquid-phase microextraction and electromembrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Jensen, Henrik; Rasmussen, Knut Einar;

    2012-01-01

    In this paper, extraction kinetics was investigated experimentally and theoretically in hollow fiber liquid-phase microextraction (HF-LPME) and electromembrane extraction (EME) with the basic drugs droperidol, haloperidol, nortriptyline, clomipramine, and clemastine as model analytes. In HF...

  1. Preparation and characterization of biomorphic SiC hollow fibers from wood by chemical vapor infiltration

    International Nuclear Information System (INIS)

    Biomorphic SiC hollow fibers were prepared by the reactive infiltration of SiO vapor into basswood-derived charcoal. Gaseous SiO was produced from a SiO2/Si powder mixture in Ar at elevated temperatures. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform-infrared spectroscopy were employed to characterize the structural morphology and phase compositions of the final products. The results show that the tubular cells in bulk charcoal are converted into lots of SiC hollow fibers with pore diameters of 10-50 μm and lengths ranging from hundreds of μm to several mm. Resulting SiC hollow fibers consist of β-SiC with a minute amount of α-SiC. The formation mechanism of SiC hollow fibers is based on the gas-solid reaction between SiO and carbon

  2. Fabrication of a wearable fabric tactile sensor produced by artificial hollow fiber

    International Nuclear Information System (INIS)

    An artificial-hollow-fiber structure as a new material for MEMS was developed and applied to a novel type of fabric tactile sensor. The artificial hollow fiber was fabricated by uniformly deposited metal and insulation layers on the surface of an elastic tube. A special rotating mechanism for uniformly depositing a metal layer on the tube surface during sputtering was developed. A rectangular-shaped fabric tactile sensor was produced by combining artificial hollow fibers and typical cotton yarns, like a cloth. The sensor can detect a contact force by measuring changes in capacitance at all intersection points of the artificial hollow fibers. Two different types of wearable-tactile-sensor glove, a patched type and a direct knit type, were also fabricated, and it was confirmed that both types can detect a normal load by measuring the capacitance change

  3. Simultaneous removal of COD and nitrogen using a novel carbon-membrane aerated biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A membrane aerated biofilm reactor is a promising technology for wastewater treatment. In this study, a carbon-membrane aerated biofilm reactor (CMABR) has been developed, to remove carbon organics and nitrogen simultaneously from one reactor. The results showed that CMABR has a high chemical oxygen demand (COD) and nitrogen removal efficiency, as it is operated with a hydraulic retention time (HRT) of 20 h, and it also showed a perfect performance, even if the HRT was shortened to 12 h. In this period, the removal efficiencies of COD, ammonia nitrogen (NH4+-N), and total nitrogen (TN) reached 86%, 94%, and 84%, respectively. However,the removal efficiencies of NH4+-N and TN declined rapidly as the HRT was shortened to 8 h. This is because of the excessive growth of biomass on the nonwoven fiber and very high organic loading rate. The fluorescence in situ hybridization (FISH) analysis indicated that the ammonia oxidizing bacteria (AOB) were mainly distributed in the inner layer of the biofilm. The coexistence of AOB and eubacteria in one biofilm can enhance the simultaneous removal of COD and nitrogen.

  4. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    Science.gov (United States)

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  5. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System.

    Science.gov (United States)

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18-22 g/m³ to a range of 13.5-18.3 g/m³. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  6. Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes

    International Nuclear Information System (INIS)

    Pertraction of Penicillin G in Hollow Fiber Contained Liquid Membranes was investigated in a system consisting of 2 Liqui Cel 106 modules from Hoechst Celanese. The flux of Pen G depended upon the content of n-octanol and of Amberlite LA2 in kerosene used as a membrane phase. During the pertraction of Pen G in HFCLM system the pH difference between the both buffered aqueous phases diminished proportionally to the contact time with the membrane phase. The flux of citric acid used as a buffer component in the feed phase attained 11.8 mM/m2 x h and was comparable with the flux of Pen G equal to 18.4 mM/m2 x h. In order to eliminate the undesired transport of citric acid, CO2 was used as a volatile buffer component. Although the pH values were stabilised in the range of 5.47 and 7.45 in the feed and strip phase, respectively, the achieved Pen G flux was significantly lower. (author)

  7. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    Directory of Open Access Journals (Sweden)

    Baiwang Zhao

    2015-11-01

    Full Text Available In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process.

  8. Separation of actinides using hollow fiber supported liquid membranes

    International Nuclear Information System (INIS)

    Hollow fiber supported liquid membrane (HFSLM) studies were carried out using TODGA (N,N,N',N'-tetraoctyl diglycolamide) - DHOA (di-n-hexyloctanamide) - NPH (normal paraffin hydrocarbon) and Cyanex-301-n-dodecane as carriers. The first carrier was employed to recover trivalent actinides and lanthanides from simulated high level waste (SHLW) of pressurized heavy water reactor (PHWR) origin. Subsequently, the mutual separation of the actinides and the lanthanides was demonstrated with the second carrier (Cyanex-301-n-dodecane). Quantitative transport of Am(III) and Nd(III) was observed in 45 min from a feed solution (500 mL) containing 1 g/L Nd spiked with 241Am at 3 M HNO3. Similarly, all the lanthanides (La, Ce, Pr, Nd and Sm) and tracer Am(III) were quantitatively recovered in 30 min from SHLW. No significant transport of other metal ions present in SHLW was observed. Quantitative and selective recovery of Am(III) was achieved by Cyanex-301-n-dodecane from feed solution containing 1 g/L total lanthanides spiked with 241Am tracer. The physical stability of HFSLM was reasonably good during continuous operation for over 72 h. Radiolytic stability of solvent and hollow fibre module up to 500 kGy dose was also satisfactory. (orig.)

  9. Dual layer hollow fiber sorbents: Concept, fabrication and characterization

    KAUST Repository

    Bhandari, Dhaval

    2013-02-01

    Hollow fiber sorbents are pseudo-monolithic separations materials created with fiber spinning technology using a polymer \\'binder\\', impregnated with high loadings of sorbent \\'fillers\\' [1]. To increase purified gas recovery during the sorption step and to ensure consistent sorption capacity over repeated cycles, a dense, thin polymer barrier layer on the fiber sorbents is needed to allow only thermal interactions between the sorbate loaded layer and the thermal regeneration fluid. This paper considers materials and methods to create delamination-free dual layer fiber sorbents, with a porous core and a barrier sheath layer formed using a simultaneous co-extrusion process. Low permeability polymers were screened for sheath layer creation, with the core layer comprising cellulose acetate polymer as binder and zeolite NaY as sorbent fillers. Appropriate core and sheath layer dope compositions were determined by the cloud-point method and rheology measurements. The morphology of the as-spun fibers was characterized in detail by SEM, EDX and gas permeation analysis. A simplified qualitative model is described to explain the observed fiber morphology. The effects of core, sheath spin dope and bore fluid compositions, spinning process parameters such as air-gap height, spin dope and coagulation bath temperatures, and elongation draw ratio are examined in detail. © 2012 Elsevier B.V. All rights reserved.

  10. A simple way to establish a dual-core hollow fiber for laser surgery applications

    Science.gov (United States)

    Jing, Chengbin; Kendall, Wesley; Harrington, James A.

    2016-03-01

    A dual-core hollow fiber has two separate cores for propagation of light. Such a fiber can have some good applications in laser surgery. The dual-core guide can transmit an infrared laser beam for cutting or ablation while a visible laser beam is simultaneously transmitted as a pilot or aiming beam. The traditional fabrication procedure for a dual-core hollow fiber involves chemical vapor deposition (CVD) growth on silica tubing of an inner cladding layer followed by the deposition of a low index polymer on the outside of the tubing. This will provide a hollow structure that has a clad-core-clad tube. This work provides an alternative approach which involves nesting of two hollow waveguides to establish a dual-core hollow fiber. An Ag/AgI hollow glass fiber is fabricated for transmitting CO2 laser. Another silica glass tube is selected carefully so that its inner diameter is just slightly larger than the outer diameter of the Ag/AgI hollow fiber. The outer surface of the as-selected glass tubing is coated with a low refractive index polymer. The Ag/AgI hollow fiber was inserted into the polymer coated silica glass tubing to establish an air or silicone oil gap between the two tubes. A visible laser beam is transmitted through the outer tube's core. The CO2 laser beam is transmitted through the inner Ag/AgI hollow fiber. The dual-core hollow fibers show good transmission for both the red aiming beam and the CO2 laser. Therefore this structure can be a good candidate for laser surgery applications.

  11. Fibrous Support Stabilizes Nitrification Performance of a Membrane-Aerated Biofilm: The Effect of Liquid Flow Perturbation

    DEFF Research Database (Denmark)

    Terada, Akihiko; Ito, J; Matsumoto, S;

    2009-01-01

    Nitrification stability and biofilm robustness were examined by comparing a fibrous support membrane-aerated biofilm reactor (FS-MABR), where a woven fibrous support was surrounded on a silicone tube, with an MABR. The overall mass transfer coefficient of oxygen for the FS-MABR, assuming no...

  12. Clarification of Orange Press Liquors by PVDF Hollow Fiber Membranes.

    Science.gov (United States)

    Simone, Silvia; Conidi, Carmela; Ursino, Claudia; Cassano, Alfredo; Figoli, Alberto

    2016-01-01

    Press liquors are typical by-products of the citrus juice processing characterized by a high content of organic compounds and associated problems of environmental impact, which imply high treatment costs. However, these wastes contain a great number of health promoting substances, including fibers, carotenoids and phenolic compounds (mainly flavonoids), whose recovery against waste-destruction technologies is very attractive for new business opportunities. In this work, the clarification of orange press liquor by using microfiltration (MF) membranes is studied as a preliminary step to obtain a permeate stream enriched in antioxidant compounds which can be further processed to produce extracts of nutraceutical and/or pharmaceutical interest. MF poly(vinylidene fluoride) (PVDF) hollow fibers were prepared by the dry/wet spinning technique. A series of fibers was produced from the same polymeric dope, in order to investigate the effect of selected spinning parameters, i.e., bore fluid composition and flowrate, on their properties. The morphology of the produced fibers was analyzed by Scanning Electron Microscopy (SEM). Fibers were further characterized for their mechanical properties, porosity, bubble point, pore size distribution and pure water permeability (PWP). Some of the produced fibers exhibited high permeability (pure water permeability ~530 L/m²·h·bar), coupled to good mechanical resistance and pore size in the range of MF membranes. These fibers were selected and used for the clarification of press liquor from orange peel processing. In optimized operating conditions, the selected fibers produced steady-state fluxes of about 41 L/m²·h with rejections towards polyphenols and total antioxidant activity of 4.1% and 1.4%, respectively. PMID:26805899

  13. Clarification of Orange Press Liquors by PVDF Hollow Fiber Membranes

    Directory of Open Access Journals (Sweden)

    Silvia Simone

    2016-01-01

    Full Text Available Press liquors are typical by-products of the citrus juice processing characterized by a high content of organic compounds and associated problems of environmental impact, which imply high treatment costs. However, these wastes contain a great number of health promoting substances, including fibers, carotenoids and phenolic compounds (mainly flavonoids, whose recovery against waste-destruction technologies is very attractive for new business opportunities. In this work, the clarification of orange press liquor by using microfiltration (MF membranes is studied as a preliminary step to obtain a permeate stream enriched in antioxidant compounds which can be further processed to produce extracts of nutraceutical and/or pharmaceutical interest. MF poly(vinylidene fluoride (PVDF hollow fibers were prepared by the dry/wet spinning technique. A series of fibers was produced from the same polymeric dope, in order to investigate the effect of selected spinning parameters, i.e., bore fluid composition and flowrate, on their properties. The morphology of the produced fibers was analyzed by Scanning Electron Microscopy (SEM. Fibers were further characterized for their mechanical properties, porosity, bubble point, pore size distribution and pure water permeability (PWP. Some of the produced fibers exhibited high permeability (pure water permeability ~530 L/m2·h·bar, coupled to good mechanical resistance and pore size in the range of MF membranes. These fibers were selected and used for the clarification of press liquor from orange peel processing. In optimized operating conditions, the selected fibers produced steady-state fluxes of about 41 L/m2·h with rejections towards polyphenols and total antioxidant activity of 4.1% and 1.4%, respectively.

  14. First application of hollow fiber filter for PWR condensate polishing

    Energy Technology Data Exchange (ETDEWEB)

    Tsuda, S. [ORGANO Corp., Tokyo (Japan); Otoha, K.; Takiguchi, H. [Japan Atomic Power Co., Tokyo (Japan)

    2002-07-01

    In Tsuruga Unit-2 (PWR 1160 MWe commenced commercial operation in 1987), current procedure for secondary system clean-up before start-up had prolonged outage time and had consumed a huge amount of de-ionized (DI) water. In addition, iron oxide in condensate had accelerated the degradation of condensate demineralizer (CD) resin. The corrosion product of iron could also influence the secondary side corrosion of steam generator (SG) tubing if it intruded into SG through CD. To solve these problems, Japan Atomic Power Company (JAPC) decided to introduce hollow fiber filter (HFF) type condensate filter into Tsuruga-2, as the first application to PWR in the world. Because of retro-fitted HFF in Tsuruga Unit-2, limitations for installation space and flow resistance in condensate system and cost reduction required new design for compact and low differential pressure system and for long life filter module. JAPC and ORGANO assessed methodologies to achieve these goals. An advanced HFF system, including a newly developed compact HFF module design, was installed at Tsuruga Unit-2 in 1997 based on the assessment. During the 5 years since the installation, the HFF system has provided excellent crud removal that enables to shorten the outage period and to reduce DI water consumption drastically. Stable differential pressure (dP) trend of the HFF system indicates an expected module life of more than 7 years, with backwash cleaning required only 2 or 3 times per year. In addition to providing the expected operating cost reduction and improved SG tube integrity, numerous additional benefits have resulted from the retrofit. (authors)

  15. Purification Lanthanum of Solvent Extraction Hollow Fiber Supported Liquid Membrane by Using Potassium Hydroxide Treatment

    International Nuclear Information System (INIS)

    Full text: The objective of this research is to purify extracted lanthanum by hollow fiber supported liquid membrane. The liquid membrane was fabricated from a solution of D2EHPA dissolved in kerosene solvent before embedded in the microstructure of porous hollow fibers. In the experiment, ammonia was used to precipitate contaminates before liquid membrane extraction. Feed solution is prepared by digesting mixed rare earth with nitric acid and precipitated contaminates with ammonia solution (pH 7.6). Nitric acid solution, used as reagent strip was passed through the outside of the hollow fiber with the flow rate of 100 ml/min, whereas the feed was flow inside the hollow fiber. Results showed that the feed solution could reduce unwanted elements up to 79.3%, resulting in lanthanum with purity over 90.8 percent. Moreover, the solvents that are extracted using supported liquid membrane module with hollow fibers were found to have high purity of lanthanum to 95.3 percent

  16. Highly scalable ZIF-based mixed-matrix hollow fiber membranes for advanced hydrocarbon separations

    KAUST Repository

    Zhang, Chen

    2014-05-29

    ZIF-8/6FDA-DAM, a proven mixed-matrix material that demonstrated remarkably enhanced C3H6/C3H8 selectivity in dense film geometry, was extended to scalable hollow fiber geometry in the current work. We successfully formed dual-layer ZIF-8/6FDA-DAM mixed-matrix hollow fiber membranes with ZIF-8 nanoparticle loading up to 30 wt % using the conventional dry-jet/wet-quench fiber spinning technique. The mixed-matrix hollow fibers showed significantly enhanced C3H6/C3H8 selectivity that was consistent with mixed-matrix dense films. Critical variables controlling successful formation of mixed-matrix hollow fiber membranes with desirable morphology and attractive transport properties were discussed. Furthermore, the effects of coating materials on selectivity recovery of partially defective fibers were investigated. To our best knowledge, this is the first article reporting successful formation of high-loading mixed-matrix hollow fiber membranes with significantly enhanced selectivity for separation of condensable olefin/paraffin mixtures. Therefore, it represents a major step in the research area of advanced mixed-matrix membranes. © 2014 American Institute of Chemical Engineers.

  17. "Modification of Polyether Sulfone (PES Hollow Fiber Membranes Characteristics for More Efficient Water Treatment Process"

    Directory of Open Access Journals (Sweden)

    A Ameri

    2004-07-01

    Full Text Available Membrane technology is used to separate water or solvents from salts or pollutants. This technique could be used for water treatment. For using of Polyether sulfone (PES hollow fiber membranes in water treatment processes, the PES hollow fiber membranes were prepared by dry-wet spinning method and heated in an oven at: 120°C, 150°C and 180°C. The effect of heating on performance of membranes was investigated in a test module with five hollow fibers, each 15 cm long, were potted at both ends with epoxy glue. Then polyethylen glycol (PEG and polyethylen oxide (PEO with different molecular weights were passed through hollow fibers. It was found that the membrane shrank by heating, which was evidenced by the reduction in flux and increase in solute separation. The best results were obtained when the hollow fibers were heated at 150°C. A further investigation was made on the effect of heating period, while the temperature was fixed to 150 °C. It was found that heating period affected membrane performance only little.

  18. Preparation and characterization of thermally stable copoly(phthalazinone biphenyl ether sulfone) hollow fiber ultrafiltration membranes

    Science.gov (United States)

    Liu, Peng; Zhang, Shouhai; Wang, Yutian; Lu, Yan; Jian, Xigao

    2015-04-01

    Novel thermally stable copoly(phthalazinone biphenyl ether sulfone) (PPBES) hollow fiber ultrafiltration (UF) membranes were successfully fabricated by the dry/wet phase inversion technique. The effects of polymer dope formulation (i.e., the PPBES concentration, different types and contents of additives) and fiber spinning conditions (i.e., air gap distance, coagulation bath temperature) on the morphologies and separation performance of PPBES hollow fiber UF membranes were investigated, respectively. It was found that the water flux of hollow fiber membrane decreased with the increase of PPBES concentration or EGME content in casting solution, while the rejection of PEG increased. However, the PPBES hollow fiber UF prepared with LiCl as inorganic small molecule additive exhibited different phenomena. In addition, the decrease of air gap distance or the increase of coagulation bath temperature could improve the water flux of UF membrane while reduce the rejection of PEG. Moreover, the thermal stability of the PPBES hollow fiber UF membranes was investigated. The water flux of PPBES membrane increased dramatically from 155 to 428 L m-2 h-1 without significant decrease of rejection when the temperature of feed solution increased from 20 °C to 95 °C.

  19. Block copolymer hollow fiber membranes with catalytic activity and pH-response

    KAUST Repository

    Hilke, Roland

    2013-08-14

    We fabricated block copolymer hollow fiber membranes with self-assembled, shell-side, uniform pore structures. The fibers in these membranes combined pores able to respond to pH and acting as chemical gates that opened above pH 4, and catalytic activity, achieved by the incorporation of gold nanoparticles. We used a dry/wet spinning process to produce the asymmetric hollow fibers and determined the conditions under which the hollow fibers were optimized to create the desired pore morphology and the necessary mechanical stability. To induce ordered micelle assembly in the doped solution, we identified an ideal solvent mixture as confirmed by small-angle X-ray scattering. We then reduced p-nitrophenol with a gold-loaded fiber to confirm the catalytic performance of the membranes. © 2013 American Chemical Society.

  20. A COMPOSITE HOLLOW FIBER MEMBRANE-BASED PERVAPORATION PROCESS FOR SEPARATION OF VOCS FROM AQUEOUS SURFACTANT SOLUTIONS. (R825511C027)

    Science.gov (United States)

    The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow fiber membrane-based pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow fibers having a thin plasma polymerized silicon...

  1. Fabrication and characterization of functionally graded poly(vinylidine fluoride)-silver nanocomposite hollow fibers for sustainable water recovery

    KAUST Repository

    Francis, Lijo

    2014-12-01

    Poly(vinylidine fluoride) (PVDF) asymmetric hydrophobic hollow fibers were fabricated successfully using dryjet wet spinning. Hydrophobic silver nanoparticles were synthesized and impregnated into the PVDF polymer matrix and functionally graded PVDF-silver nanocomposite hollow fibers are fabricated and tested in the direct contact membrane distillation (DCMD) process. The as-synthesized silver nanoparticles were characterized for Transmission Electron Microscopy (TEM), particle size distribution (PSD) and Ultra Violet (UV) visible spectroscopy. Both the PVDF and PVDF-silver nanocomposite asymmetric hollow fibers were characterized for their morphology, water contact angle and mechanical strength. Addition of hydrophobic silver nanoparticles was found to enhance the hydrophobicity and ~ 2.5 fold increase the mechanical strength of the hollow fibers. A water vapor flux of 31.9kg m-2 h-1 was observed at a feed inlet temperature of 80 °C and at a permeate temperature of 20 °C in the case of hollow fiber membrane modules fabricated using PVDF hollow fibers; the water vapor flux was found to be increased by about 8% and to reach 34.6kg m-2 h-1 for the hollow fiber membrane modules fabricated from the PVDF-silver nanocomposite hollow fibers at the same operating conditions with 99.99% salt rejection.

  2. Investigation of leaks in fiberglass-reinforced pressure vessels by direct observation of hollow fibers in glass cloth

    International Nuclear Information System (INIS)

    A simple method of visual observation of hollow fibers within fiberglass cloth has been developed. This visualization can aid in determining the contribution these fibers make toward leaks observed in fiberglass-reinforced epoxy resin pressure or vacuum vessels. Photographs and frequency data of these hollow fibers are provided. 3 figs

  3. Rapid Temperature Swing Adsorption using Polymeric/Supported Amine Hollow Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Chance, Ronald [Georgia Tech Research Corporation, Atlanta, GA (United States); Chen, Grace [Georgia Tech Research Corporation, Atlanta, GA (United States); Dai, Ying [Georgia Tech Research Corporation, Atlanta, GA (United States); Fan, Yanfang [Georgia Tech Research Corporation, Atlanta, GA (United States); Jones, Christopher [Georgia Tech Research Corporation, Atlanta, GA (United States); Kalyanaraman, Jayashree [Georgia Tech Research Corporation, Atlanta, GA (United States); Kawajiri, Yoshiaki [Georgia Tech Research Corporation, Atlanta, GA (United States); Koros, William [Georgia Tech Research Corporation, Atlanta, GA (United States); Lively, Ryan [Georgia Tech Research Corporation, Atlanta, GA (United States); McCool, Benjamin [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States); Realff, Matthew [Georgia Tech Research Corporation, Atlanta, GA (United States); Rezaei, Fateme [Georgia Tech Research Corporation, Atlanta, GA (United States); Searcy, Katherine [Georgia Tech Research Corporation, Atlanta, GA (United States); Sholl, David [Georgia Tech Research Corporation, Atlanta, GA (United States); Subramanian, Swernath [Georgia Tech Research Corporation, Atlanta, GA (United States); Pang, Simon [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2015-03-31

    This project is a bench-scale, post-combustion capture project carried out at Georgia Tech (GT) with support and collaboration with GE, Algenol Biofuels, Southern Company and subcontract to Trimeric Corporation. The focus of the project is to develop a process based on composite amine-functionalized oxide / polymer hollow fibers for use as contactors in a rapid temperature swing adsorption post-combustion carbon dioxide capture process. The hollow fiber morphology allows coupling of efficient heat transfer with effective gas contacting, potentially giving lower parasitic loads on the power plant compared to traditional contacting strategies using solid sorbents.

  4. Preparation of [11C]formaldehyde using a hollow fiber membrane bioreactor

    International Nuclear Information System (INIS)

    A bioreactor consisting of the enzymes alcohol oxidase and catalase immobilized onto a hollow fiber membrane was used to convert [11C]methanol to [11C]formaldehyde. Using an alcohol oxidase:catalase ratio of 1:500 U, conversion yields of 90-95% were obtained allowing the production of up to 7400 MBq (200 mCi) of [11C]formaldehyde in 5 min. The hollow fiber bioreactor allowed for a convenient, rapid synthesis with yields significantly higher than the standard chemical procedures, has demonstrable advantages over glass bead immobilized systems (primarily due to convective flow), and was amenable to hot cell conditions

  5. Fuel cell components and systems having carbon-containing electrically-conductive hollow fibers

    Energy Technology Data Exchange (ETDEWEB)

    Langry, Kevin C; Farmer, Joseph C

    2015-04-28

    A method, according to one embodiment, includes acquiring a structure having an ionically-conductive, electrically-resistive electrolyte/separator layer covering an inner or outer surface of a carbon-containing electrically-conductive hollow fiber and a catalyst along one side thereof, adding an anode that extends along at least part of a length of the structure, and adding a cathode that extends along at least part of the length of the structure, the cathode being on an opposite side of the hollow fiber as the anode.

  6. Multi-walled Carbon Nano tubes/ Polyetherimide Composite Hollow Fibers for Gas Separation

    International Nuclear Information System (INIS)

    Composite hollow fibers were prepared by incorporating 1 wt % of multi walled carbon nano tubes (MWCNTs) within polyether imide (PEI) polymer matrix. Surfactant modification using non-ionic surfactant, Triton X100 was conducted to improve the dispersion of nano tubes in the polymer matrix during the preparation of polymer dope. The morphological structure and mechanical properties of the resulting composite hollow fibers were characterized. This study demonstrated the role of Triton X100 in facilitating the synergetic effects of MWCNTs and PEI where the resulting composite membrane is anticipated to have potential application in membrane based gas separation. (author)

  7. Structure and Properties of Polyurethane/Polyvinylidene Difluoride Blending Hollow Fiber

    Institute of Scientific and Technical Information of China (English)

    HU Xiao-yu; XIAO Chang-fa; AN Shu-lin; WANG Zhao-xu

    2006-01-01

    Utilization of polyvinylidene difluoride, PVDF, as the disperse phase and thermal plastic polyurethane, PU, as the continuous phase, the PU/PVDF blend hollow fiber membranes with the property of pressure-responsibility,PR, was prepared by melt- spinning. For these hollow fibers, the formation of the interfacial micro-voids, IFM,and the spinability of the blend were analyzed. The pressure-responsibility was studied by measuring the changing of pure water flux, PWF, with the pressure, and the influence of drawing and heat-setting on the structure and pressure-responsibility of the membranes were also discussed.

  8. Multi-mJ pulse compression in hollow fibers using circular polarization

    Science.gov (United States)

    Malvache, A.; Chen, X.; Durfee, C. G.; Jullien, A.; Lopez-Martens, R.

    2011-07-01

    We develop a numerical model to explore the polarization-dependent compression of multi-mJ laser pulses in a gas-filled hollow fiber. We show how losses and instabilities due to cycling of pulse energy between fiber modes can be efficiently minimized using circularly polarized light and adjusting simple experimental parameters such as pulse energy, chirp and gas pressure. This should help scale the peak power of few-cycle pulses available for high-field experiments using standard hollow fiber compressors. We also discuss the limits of this approach.

  9. Hollow fiber membranes for advanced life support systems. [permeable capillaries for medical filtration

    Science.gov (United States)

    Roebelen, G. J., Jr.; Lysaght, M. J.

    1977-01-01

    This paper describes an investigation of the practicability of utilizing hollow fiber membranes in vehicular and portable life support system applications. A preliminary screening of potential advanced life support applications resulted in the selection of five applications for feasibility study and testing. As a result of the feasibility study and testing, three applications, heat rejection, deaeration, and bacteria filtration, were chosen for breadboard development testing. Breadboard hardware has been manufactured and tested, and the physical properties of the three hollow fiber membrane assemblies applicable to use aboard future spacecraft have been characterized.

  10. A mathematical model for prediction of pertraction of uranium in hollow fiber contactor

    International Nuclear Information System (INIS)

    A mathematical model has been developed to predict the transport of uranium through Dispersed Liquid Membrane (DLM) configuration in hollow fiber contactor using TBP as extractant in dodecane diluent with sodium carbonate as strippant. The prediction of the model has been substantiated with experimental results. Parametric studies have been conducted and a few of them have been presented here. The model takes into account complexation reaction at the aqueous-organic interface at the pores of hollow fiber lumens and predicts the rate of change of concentration in the aqueous feed phase flowing through the lumens in re-circulating mode. (author)

  11. Partitioning of plutonium from aqueous acidic wastes using a hollow fiber supported liquid membrane technique

    International Nuclear Information System (INIS)

    Transport of Pu(IV) from 3M HNO3 solutions across Aliquat-336/ Solvesso-100 by hollow fiber supported liquid membrane (HFSLM) was studied. Permeability of Pu(IV) through a bundle of hollow fibers made-up with 20 lumens, of 67 cm2 surface area, 9 cm length and operated at a flow rate of 10-8 m3/s on recycle mode was examined. More than 80% Pu from oxalate bearing wastes generated during reconversion process could be transported through 10% Aliquat-336/Solvesso-100 into hydroxylamine hydrochloride strippant in about three runs. (author)

  12. Response surface methodology to evaluation the recovery of amylases by hollow fiber membrane

    OpenAIRE

    João Baptista Severo Júnior; Laura Sampaio de Sá Oliveira; Fernanda Silva Sardeiro; Roberto Rodrigues de Souza; Francisco Luiz Gumes Lopes; José Carlos Curvelo Santana; Elias Basile Tambourgi

    2007-01-01

    This work aimed to study the pH and the transmembrane pressure effects during the recovery of alpha and beta amylases enzymes from corn malt (Zea mays) by hollow fiber membrane. The optimal condition was obtained for a statistical model, established by response surface methodology (RSM). The response surface analysis showed that the best operation condition for amylolitics enzymes recovery by hollow fiber membrane was 0.05 bar and pH 5.00, while the enzymes were purified about of 26 times.Est...

  13. Performance analysis of a pilot-scale membrane aerated biofilm reactor for the treatment of landfill leachate

    OpenAIRE

    Syron, Eoin; Semmens, Michael J.; CASEY, Eoin

    2015-01-01

    A 60 L membrane aerated biofilm reactor (MABR) was successfully employed to treat landfill leachate, which contained very high concentrations of refractory chemical oxygen demand (COD) and ammonium. Air or pure oxygen was supplied to the bioreactor through polydimethyl siloxane hollow fibre membranes. Over a year of operation with an average hydraulic retention time of about 5 days, and influent ammonium concentrations ranging from 500 to 2500 mg/L, the MABR achieved 80–99% nitrification. Sim...

  14. Economic comparison of transverse and longitudinal flow hollow fiber membrane modules for reverse osmosis and ultrafiltration

    NARCIS (Netherlands)

    Futselaar, H.; Zoontjes, R.J.C.; Reith, T.; Rácz, I.G.

    1993-01-01

    The presently used hollow fiber membrane modules consist of a bundle of fibers in a cylindrical polymer or metal shell parallel to the shell axis. The feed solution flows either through the lumen or at the outside parallel to the fibers. This paper compares the performance of these modules with a ne

  15. Polymeric hollow fiber membranes for bioartificial organs and tissue engineering applications

    NARCIS (Netherlands)

    Diban Ibrahim Gomez, N.; Stamatialis, D.

    2014-01-01

    Polymeric hollow fiber (HF) membranes are commercially available, i.e. microfiltration and ultrafiltration cartridges or reverse osmosis and gas separation modules, to be applied for separation purposes in industry, for instance to recover valuable raw materials or products, or for the treatment of

  16. Plastic hollow fibers employed for CO2 laser power transmission in oral surgery

    Science.gov (United States)

    Calderon, Shlomo; Gannot, Israel; Dror, Jacob; Dahan, Reuben; Croitoru, Nathan I.

    1991-07-01

    Plastic hollow fibers were developed and produced in a lab. The fiber structure was investigated by various methods. Correlation between the analysis results and the transmission characteristics was found. The fibers were used in maxillofacial surgery and excellent results of healing were achieved.

  17. Preparation and microwave properties of Ni hollow fiber by electroless plating-template method

    International Nuclear Information System (INIS)

    Nickel-coated silk composites (Ni/silk fiber) were prepared by electroless nickel-plating using a kind of natural silk as template in first stage. The silk templates were then removed to get Ni hollow fiber by annealing the Ni/silk fiber at 220 deg. C for 2 h in air or 700 deg. C for 1.5 h in nitrogen. The prepared Ni/silk fiber and Ni hollow fiber were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FE-SEM) and differential thermal analysis and thermogravimetric analysis (TG-DTA). The values of complex permittivity, complex permeability, dielectric and magnetic loss of Ni/silk fiber and Ni hollow fiber were measured in the frequency range of 2-18 GHz by a reflection/transmission approach using a network analyzer. The results indicate that the dielectric loss of Ni/silk fiber and Ni hollow fiber is high up to 1 even at 18 GHz while the magnetic loss is low

  18. CO2 absorption at elevated pressures using a hollow fiber membrane contactor

    NARCIS (Netherlands)

    Dindore, V.Y.; Brilman, D.W.F.; Feron, P.H.M.; Versteeg, G.F.

    2004-01-01

    Recently, hollow fiber membrane gas–liquid contactor-based processes have gained an increasing attention. Compared to conventional processes, these processes have numerous advantages. The membrane contactors provide a very high interfacial area per unit volume, independent regulation of gas and liqu

  19. Hollow Fiber Space Suit Water Membrane Evaporator Development for Lunar Missions

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis A.; Hanford, Anthony J.; Mitchell, Keith

    2009-01-01

    The Space Suit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The Hollow Fiber (HoFi) SWME is being considered for service in the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS) to provide cooling to the thermal loop through water evaporation to the vacuum of space. Previous work described the test methodology and planning to compare the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME: 1) porous hydrophobic polypropylene, 2) porous hydrophobic polysulfone, and 3) ion exchange through nonporous hydrophilic modified Nafion. Contamination tests were performed to probe for sensitivities of the candidate SWME elements to organics and non-volative inorganics expected to be found in the target feedwater source, i.e., potable water provided by the vehicle. The resulting presence of precipitate in the coolant water could plug pores and tube channels and affect the SWME performance. From this prior work, a commercial porous hydrophobic hollow fiber was selected to satisfy both the sensitivity question and the need to provide 800 W of heat rejection. This paper describes the trade studies, the design methodology, and the hollow fiber test data used to design a full

  20. Enhancement of antibody production by growth factor addition in perfusion and hollow-fiber culture systems.

    Science.gov (United States)

    Omasa, T; Kobayashi, M; Nishikawa, T; Shioya, S; Suga, K; Uemura, S; Kitani, Y; Imamura, Y

    1995-12-20

    The effects of the high-molecular-weight growth factors, transferrin and bovine serum albumin (BSA), on antibody production were analyzed quantitatively in continuous hollow-fiber cultivation over a period of 60 days. Transferrin enhanced cell growth but had no significant effect on the specific antibody production rate, whereas BSA significantly enhanced antibody production. The antibody production rate was increased 4- and 14-fold respectively by feeding BSA at 2 and 5 g L(-1) into the EC side of the system (the side connected to the cell-containing outer part of the hollow-fiber unit) compared with the production achieved without BSA. Addition of 5 g L(1) BSA into the IC side of the system (the side connected to the inner part of the hollow-fiber unit) resulted in a 2.5-fold increase in the antibody production rate. The effect of BSA was also analyzed using the perfusion culture system with a separation unit. When fresh medium containing either 2 or 5 g L(-1) BSA was fed into the reactor, both the specific growth rate and specific death rate increased, while the specific antibody production rate was increased 2- and 25-fold, respectively, by feeding BSA at these two concentrations compared with no addition. Comparing the two systems, the increase in the antibody production rate achieved with the hollow-fiber system was threefold greater than that in the perfusion culture system with the same concentration of BSA feeding. (c) 1995 John Wiley & Sons, Inc. PMID:18623537

  1. Cell carrier function of hollow-fiber membrane in rotating wall vessel bioreactor

    Institute of Scientific and Technical Information of China (English)

    Kedong SONG; Tianqing LIU; Hu ZHAO; Xiangqin LI; Zhanfeng CUI; Xuehu MA

    2008-01-01

    Large-scale expansion of the osteoblasts of a Sprague-Dawley (SD) rat was studied in a rotating wall hollow-fiber membrane bioreactor (RWHMB) by using hollow-fiber membrane as the carrier. For the sake of contrast, cells were also expanded in a T-flask using a hollow-fiber membrane as carrier and in a rotating wall vessel bioreactor (RWVB) using a microcarrier. During the culture period, the cells were sampled every 12 h, and after 5 days, the cells were harvested and evaluated with scanning electron microscopy (SEM), hematoxylin-eosin (HE) staining and alkaline phosphatase (ALP) staining. Moreover, von-Kossa staining and Alizarin Red S stain-ing were carried out for mineralized nodules formation. The results show that in RWHMB, the cells present better morphology and vitality and secrete much more extracel-lular matrix. It is concluded that the RWHMB combines the advantages of the rotating wall vessel and hollow-fiber membrane bioreactors. The hydrodynamic stimulation within it accelerates the metabolism of the osteoblast and mass transfer, which is propitious to cell differenti-ation and proliferation.

  2. Rapid Startup and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    Science.gov (United States)

    Meyer, Caitlin; Vega, Leticia

    2014-01-01

    The Membrane Aerated Bioreactor (MABR) is an attached-growth biological system for simultaneous nitrification and denitrification. This design is an innovative approach to common terrestrial wastewater treatments for nitrogen and carbon removal. Implementing a biologically-based water treatment system for long-duration human exploration is an attractive, low energy alternative to physiochemical processes. Two obstacles to implementing such a system are (1) the "start-up" duration from inoculation to steady-state operations and (2) the amount of surface area needed for the biological activity to occur. The Advanced Water Recovery Systems (AWRS) team at JSC explored these two issues through two tests; a rapid inoculation study and a wastewater loading study. Results from these tests demonstrate that the duration from inoculation to steady state can be reduced to two weeks and that the surface area to volume ratio baseline used in the Alternative Water Processor (AWP) test was higher than what was needed to remove the organic carbon and ammonium from the system.

  3. Applications of titania and zirconia hollow fibers in sorptive microextraction of N,N-dimethylacetamide from water sample.

    Science.gov (United States)

    Li, Jia; Qi, Huan-Yang; Shi, Yan-Ping

    2009-10-01

    The convenient fabrications of titania and zirconia hollow fiber with three-dimensional porous structure using polypropylene hollow fibers as templates were developed. And an analytical method based on enrichment and extraction of analytes in the water sample, hollow fiber sorptive microextraction in combined with gas chromatography has been developed for the rapid analysis of N,N-dimethylacetamide (DMA) in the environmental samples. The results showed that zirconia hollow fiber gave higher extraction performance of DMA than that of titania hollow fiber. The method validations, including linearity, limit of detection, limit of qualification, precision, and repeatability were investigated. Linearity for six-point calibration curve was excellent with zirconia hollow fiber having r2 value greater than 0.9993 at the linearity range of 0.001-1.0 mg mL(-1). In addition, it seems that hollow fiber sorptive extraction is a promising technique for the enrichment and purification of analytes extracted directly from liquid samples without any other pretreatment. PMID:19782809

  4. Treatment of Spacecraft Wastewater Using a Hollow Fiber Membrane Biofilm Redox Control Reactor

    Science.gov (United States)

    Smith, Daniel P.

    2003-01-01

    The purpose of this project was to develop and evaluate design concepts for biological treatment reactors for the purification of spacecraft wastewater prior to reverse osmosis treatment. The motivating factor is that wastewater recovery represents the greatest single potential reduction in the resupply requirements for crewed space missions. Spacecraft wastewater composition was estimated from the characteristics of the three major component streams: urine/flush water, hygiene water, and atmospheric condensate. The key characteristics of composite spacecraft wastewater are a theoretical oxygen demand of 4519 mg/L, of which 65% is nitrogenous oxygen demand, in a volume of 11.5 liter/crew-day. The organic carbon to nitrogen ratio of composite wastewater is 0.86. Urine represents 93% of nitrogen and 49% of the organic carbon in the composite wastestream. Various bioreaction scenarios were evaluated to project stoichiometric oxygen demands and the ability of wastewater carbon to support denitrification. Ammonia nitrification to the nitrite oxidation state reduced the oxygen requirement and enabled wastewater carbon to provide nearly complete denitrification. A conceptual bioreactor design was established using hollow fiber membranes for bubbleless oxygen transfer in a gravity-free environment, in close spatial juxtaposition to a second interspaced hollow fiber array for supplying molecular hydrogen. Highly versatile redox control and an enhanced ability to engineer syntrophic associations are stated advantages. A prototype reactor was constructed using a microporous hollow fiber membrane module for aeration. Maintaining inlet gas pressure within 0.25 psi of the external water pressure resulted in bubble free operation with no water ingress into hollow fiber lumens. Recommendations include the design and operational testing of hollow fiber bioreactors using: 1) Partial nitrification/nitrite predenitrification; 2) Limited aeration for simultaneous nitrification

  5. Formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes for gas separations

    KAUST Repository

    Xu, Liren

    2014-06-01

    This paper reports the formation of defect-free 6FDA-DAM asymmetric hollow fiber membranes. 6FDA-polyimides are of great interest for advanced gas separation membranes, and 6FDA-DAM polyimide is a representative polymer in this family with attractive dense film properties for several potential applications. The work reported here for the 6FDA-DAM polyimide provides insight for the challenging fabrication of defect-free asymmetric hollow fiber membranes for this class of 6FDA-polyimides, which behave rather different from lower free volume polymers. Specifically, the 6FDA based materials show relatively slow phase separation rate in water quench baths, which presents a challenge for fiber spinning. For convenience, we refer to the behavior as more "non-solvent resistant" in comparison to other lower free volume polymers, since the binodal phase boundary is displaced further from the conventional position near the pure polymer-solvent axis on a ternary phase diagram in conventional polymers like Matrimid® and Ultem®. The addition of lithium nitrate to promote phase separation has a useful impact on 6FDA-DAM asymmetric hollow fiber formation. 6FDA-DAM phase diagrams using ethanol and water as non-solvent are reported, and it was found that water is less desirable as a non-solvent dope additive for defect-free fiber spinning. Phase diagrams are also reported for 6FDA-DAM dope formulation with and without the addition of lithium nitrate, and defect-free asymmetric hollow fiber membranes are reported for both cases. The effect of polymer molecular weight on defect-free fiber spinning was also investigated. Gas transport properties and morphology of hollow fibers were characterized. With several thorough case studies, this work provides a systematic guideline for defect-free fiber formation from 6FDA-polymers. © 2014 Elsevier B.V.

  6. Pseudo-emulsion based hollow fiber strip dispersion technique modeling and application for Pu (IV) recovery from oxalate supernatant waste

    International Nuclear Information System (INIS)

    The extraction - recovery of Pu(IV) from nitric acidic medium has been examined by PEHFSD (Pseudo-emulsion based hollow fiber strip dispersion) in a microporous hydrophobic polypropylene hollow fiber membrane contactor. The technology of supported liquid membranes with strip dispersion has advantages over the conventional supported liquid membranes solving the inherent stability problems of the membrane. Mathematical models for extraction in hollow-fiber contactor were also developed. The mass transfer coefficients were calculated from the experimental results and models are presented. The applicability of PEHFSD technique was demonstrated for recovery of Pu(IV) from oxalate supernatant waste generated during plutonium precipitation by oxalic acid. (author)

  7. MEMBRANE-MODERATED STRIPPING PROCESS FOR REMOVING VOCS FROM WATER IN A COMPOSITE HOLLOW FIBER MODULE. (R825511C027)

    Science.gov (United States)

    The "stripmeation" process for removing volatile organic compounds (VOCs) from water has been introduced and studied. An aqueous solution of the VOC is passed through the bores of hydrophobic microporous polypropylene hollow fibers having a plasma polymerized silicone ...

  8. Catalytic Hollow-Fiber Membranes Prepared Using Layer-by-Layer Adsorption of Polyelectrolytes and Metal Nanoparticles

    OpenAIRE

    Ouyang, Lu; Dotzauer, David M.; Hogg, Seth R.; Macanas, Jorge; Lahitte, Jean-Francois; Bruening, Merlin L.

    2010-01-01

    Immobilization of metal nanoparticles in hollow fiber membranes via alternating adsorption of polyelectrolytes and negatively charged Au nanoparticles yields catalytic reactors with high surface areas. SEM images show that this technique deposits a high density of unaggregated metal nanoparticles both on the surfaces and in the pores of the hollow fibers. Catalytic reduction of 4-nitrophenol with NaBH4, which can be easily monitored by UV-Vis spectrophotometry, demonstrates that the nanopar...

  9. A CONDENSED REVIEW ON THE FABRICATION OF HOLLOW FIBER MEMBRANES FOR GAS SEPARATION:HISTORICAL DEVELOPMENT AND TECHNOLOGY CHALLENGES AHEAD

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    IntroductionPolymeric hollow fiber membranes for gasseparation are marketing driving high-performanceproducts. In mad cases, polymeric hollow fibermembranes were Produced Prior tO the ~ntalunderstanding of detailed fabrication mechanisms.Even todsy, moSt membrane scielltiSts admit that weunderstand hollow fiber forming mechanismqualitatively, not qualitatively. New hollow fibermembranes were invented mainly baSed on our.experience, empirical data, limited qualitativelyscientific nude~ding, trial and ~ and l...

  10. MORPHOLOGIES AND GAS SEPARATION PROPERTIES OF MELT-SPUN ASYMMETRIC POLY(4-METHYL-1-PENTENE) HOLLOW FIBER MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Jian-li Wang; Zhi-kang Xu; You-yi Xu

    2003-01-01

    Poly(4-methyl-1-pentene) (PMP) hollow fiber membranes were prepared by the melt-spun and cold-stretch(MSCS) method. Scanning electronic microscopy (SEM) was used to characterize the section and surface structures of the membranes with special asymmetric structure. The preliminary results of gas permeation measurements indicated that the resultant hollow fiber membranes have the potential ability for oxygen/nitrogen separation.

  11. Evaluation of T2* change in hollow fiber dialyzer after bolus injection of gadopentetate dimeglumine

    International Nuclear Information System (INIS)

    It has been demonstrated in a simulation that diffusion is an important component in determining T2* contrast. When a high-susceptibility agent permeates from intravascular to extracellular space, the changes in its spatial distribution affect the signal intensity of T2*-weighted images so as to potentially represent a diffusion process. To experimentally demonstrate the effects of permeation on T2*-weighted images, we assessed the dynamic changes in T2* signal after a bolus injection of Gd-DTPA (Magnevist: Schering) solution into a hollow fiber dialyzer as a phantom of intravascular and extracellular space. The signal intensity of the hollow fiber dialyzer in gradient-echo images was compared with that in spin-echo images. (author)

  12. Study on the enrichment of Sulfur Hexafluoride in the tmosphere through polyimide hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Wang Weixian

    2016-01-01

    Full Text Available Sulfur hexafluoride is per molecule the strongest greenhouse gas know, the features have brought SF6 into the climatic impact discussion aimed at reduction of emissions. The separation effects of sulfur hexafluoride in the atmosphere are studied through polyimide hollow fiber membrane with different conditions on pressure drop, gas flow and temperature. The sulfur hexafluoride concentration increased with increased pressure drop of the membrane, increased temperature and decreased non-filtrate flow flux; the recovery of sulfur hexafluoride exceeds 93%, enrichment coefficient was 18.5; sulfur hexafluoride is not detected at the flux of the filtrate flow, which means sulfur hexafluoride is riddled by membrane. The results showed that polyimide hollow fiber membrane can effectively separate sulfur hexafluoride from mixed gas

  13. Dual membrane hollow fiber fuel cell and method of operating same

    Science.gov (United States)

    Ingham, J. D.; Lawson, D. D. (Inventor)

    1978-01-01

    A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolytes and electrically connected. As hydrogen and oxygen flow through the bore of the fibers, oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained.

  14. Integrated hollow fiber membranes for gas delivery into optical waveguide based photobioreactors.

    Science.gov (United States)

    Ahsan, Syed Saad; Gumus, Abdurrahman; Jain, Aadhar; Angenent, Largus T; Erickson, David

    2015-09-01

    Compact algal reactors are presented with: (1) closely stacked layers of waveguides to decrease light-path to enable larger optimal light-zones; (2) waveguides containing scatterers to uniformly distribute light; and (3) hollow fiber membranes to reduce energy required for gas transfer. The reactors are optimized by characterizing the aeration of different gases through hollow fiber membranes and characterizing light intensities at different culture densities. Close to 65% improvement in plateau peak productivities was achieved under low light-intensity growth experiments while maintaining 90% average/peak productivity output during 7-h light cycles. With associated mixing costs of ∼ 1 mW/L, several magnitudes smaller than closed photobioreactors, a twofold increase is realized in growth ramp rates with carbonated gas streams under high light intensities, and close to 20% output improvement across light intensities in reactors loaded with high density cultures. PMID:26116445

  15. Development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    Syed Mohd Saufi

    2002-11-01

    Full Text Available This paper reports the development and characterization of polyacrylonitrile (PAN based carbon hollow fiber membrane. Nitrogen was used as an inert gas during pyrolysis of the PAN hollow fiber membrane into carbon membrane. PAN membranes were pyrolyzed at temperature ranging from 500oC to 800oC for 30 minutes of thermal soak time. Scanning Electron Microscope (SEM, Fourier Transform Infrared Spectroscopy (FTIR and gas sorption analysis were applied to characterize the PAN based carbon membrane. Pyrolysis temperature was found to significantly change the structure and properties of carbon membrane. FTIR results concluded that the carbon yield still could be increased by pyrolyzing PAN membranes at temperature higher than 800oC since the existence of other functional group instead of CH group. Gas adsorption analysis showed that the average pore diameter increased up to 800oC.

  16. PVDF hollow fiber and nanofiber membranes for fresh water reclamation using membrane distillation

    KAUST Repository

    Francis, Lijo

    2013-11-26

    Polyvinylidene fluoride hollow fiber and nanofibrous membranes are engineered and successfully fabricated using dry-jet wet spinning and electrospinning techniques, respectively. Fabricated membranes are characterized for their morphology, average pore size, pore size distribution, nanofiber diameter distribution, thickness, and water contact angle. Direct contact membrane distillation (DCMD) performances of the fabricated membranes have been investigated using a locally designed and fabricated, fully automated MD bench scale unit and DCMD module. Electrospun nanofibrous membranes showed a water flux as high as 36 L m-2 h-1 whereas hollow fiber membranes showed a water flux of 31.6 L m-2 h-1, at a feed inlet temperature of 80 °C and at a permeate inlet temperature of 20 °C.

  17. Effects of CO 2 on a High Performance Hollow-Fiber Membrane for Natural Gas Purification

    KAUST Repository

    Omole, Imona C.

    2010-05-19

    A 6FDA-based, cross-linkable polyimide was characterized in the form of a defect-free asymmetric hollow-fiber membrane. The novel membrane was cross-linked at various temperatures and tested for natural gas purification in the presence of high CO2 partial pressures. The cross-linked membrane material shows high intrinsic separation performance for CO2 and CH4 (selectivity ∼49, CO2 permeability ∼161 barrer, with a feed at 65 psia, 35 °C, and 10% CO2). Cross-linked asymmetric hollow-fiber membranes made from the material show good resistance to CO2-induced plasticization. Carbon dioxide partial pressures as high as ∼400 psia were employed, and the membrane was shown to be promisingly stable under these aggressive conditions. The performance of the membrane was also analyzed using the dual-mode sorption/transport model. © 2010 American Chemical Society.

  18. Carbonic anhydrase immobilized on hollow fiber membranes using glutaraldehyde activated chitosan for artificial lung applications

    OpenAIRE

    Kimmel, J. D.; Arazawa, D. T.; Ye, S.-H.; Shankarraman, V; Wagner, W. R.; Federspiel, W. J.

    2013-01-01

    Extracorporeal CO2 removal from circulating blood is a promising therapeutic modality for the treatment of acute respiratory failure. The enzyme carbonic anhydrase accelerates CO2 removal within gas exchange devices by locally catalyzing HCO3− into gaseous CO2 within the blood. In this work, we covalently immobilized carbonic anhydrase on the surface of polypropylene hollow fiber membranes using glutaraldehyde activated chitosan tethering to amplify the density of reactive amine functional gr...

  19. Hemocompatibility Assessment of Carbonic Anhydrase Modified Hollow Fiber Membranes for Artificial Lungs

    OpenAIRE

    Oh, Heung-Il; Ye, Sang-Ho; Johnson, Carl A.; Woolley, Joshua R.; Federspiel, William J.; Wagner, William R.

    2010-01-01

    Hollow fiber membrane (HFM)-based artificial lungs can require a large blood-contacting membrane surface area to provide adequate gas exchange. However, such a large surface area presents significant challenges to hemocompatibility. One method to improve carbon dioxide (CO2) transfer efficiency might be to immobilize carbonic anhydrase (CA) onto the surface of conventional HFMs. By catalyzing the dehydration of bicarbonate in blood, CA has been shown to facilitate diffusion of CO2 toward the ...

  20. Matrimid® derived carbon molecular sieve hollow fiber membranes for ethylene/ethane separation

    KAUST Repository

    Xu, Liren

    2011-09-01

    Carbon molecular sieve (CMS) membranes have shown promising separation performance compared to conventional polymeric membranes. Translating the very attractive separation properties from dense films to hollow fibers is important for applying CMS materials in realistic gas separations. The very challenging ethylene/ethane separation is the primary target of this work. Matrimid® derived CMS hollow fiber membranes have been investigated in this work. Resultant CMS fiber showed interesting separation performance for several gas pairs, especially high selectivity for C2H4/C2H6. Our comparative study between dense film and hollow fiber revealed very similar selectivity for both configurations; however, a significant difference exists in the effective separation layer thickness between precursor fibers and their resultant CMS fibers. SEM results showed that the deviation was essentially due to the collapse of the porous substructure of the precursor fiber. Polymer chain flexibility (relatively low glass transition temperature (Tg) for Matrimid® relative to actual CMS formation) appears to be the fundamental cause of substructure collapse. This collapse phenomenon must be addressed in all cases involving intense heat-treatment near or above Tg. We also found that the defect-free property of the precursor fiber was not a simple predictor of CMS fiber performance. Even some precursor fibers with Knudsen diffusion selectivity could be transformed into highly selective CMS fibers for the Matrimid® precursor. To overcome the permeance loss problem caused by substructure collapse, several engineering approaches were considered. Mixed gas permeation results under realistic conditions demonstrate the excellent performance of CMS hollow fiber membrane for the challenging ethylene/ethane separation. © 2011 Elsevier B.V.

  1. Characterization of hollow fiber hemodialysis membranes: pore size distribution and performance

    OpenAIRE

    Broek, Arnold P.; Teunis, Herman A.; Bargeman, Derk; Sprengers, Erik D.; Smolders, Cees A.

    1992-01-01

    The effect of two commonly used sterilization methods for artificial kidneys on the morphology and performance of hollow fiber Hemophan® hemodialysis membranes was studied. A relatively new membrane characterization method, thermoporometry, was used to determine the pore size distributions and porosities of the differently treated membrane samples. The samples used for this study were not treated with a concentrated glycerol solution before sterilization. Hemophan was found to have a pore siz...

  2. Enzymatic hydrolysis of corn stalk in a hollow fiber ultrafiltration membrane reactor

    International Nuclear Information System (INIS)

    A hollow fiber ultrafiltration (UF) membrane reactor was set up to investigate the enzymatic hydrolysis of steam-exploded corn stalk. It was found that the hydrolysis rate, as well as the reducing sugar (RS) yield, could be markedly enhanced in the UF membrane reactor due to the continuous removal of inhibitory products. Compared with traditional batch hydrolysis, the hydrolysis rate and RS yield could increase 200% and 206%, respectively

  3. Steady-state coupled transport of HNO3 through a hollow-fiber supported liquid membrane

    International Nuclear Information System (INIS)

    Nitric acid removal from an aqueous stream was accomplished by continuously passing the fluid through a hollow fiber supported liquid membrane (SLM). The nitric acid was extracted through the membrane wall by coupled transport. The system was modeled as a series of (SLM)-continuous stirred tank reactor (CSTR) pairs. An approximate technique was used to predict the steady state nitric acid concentration in the system. The comparison with experimental data was very good

  4. Possibilities of Hollow Fiber Microextraction and Voltammetric Detection of Homovanillic acid

    Czech Academy of Sciences Publication Activity Database

    Hrdlička, V.; Barek, J.; Navrátil, Tomáš

    Ústí nad Labem: Best servis, 2016 - (Navrátil, T.; Fojta, M.; Schwarzová, K.), s. 74-77 ISBN 978-80-905221-4-5. [Moderní elektrochemické metody /36./. Jetřichovice (CZ), 23.05.2016-27.05.2016] Institutional support: RVO:61388955 Keywords : Hollow-fibers * Liquid phase microextraction * voltammetry Subject RIV: CG - Electrochemistry

  5. Study on the enrichment of Sulfur Hexafluoride in the tmosphere through polyimide hollow fiber membrane

    OpenAIRE

    Wang Weixian; Wang Yaoqin; Li Weiping; Yuan Yuan

    2016-01-01

    Sulfur hexafluoride is per molecule the strongest greenhouse gas know, the features have brought SF6 into the climatic impact discussion aimed at reduction of emissions. The separation effects of sulfur hexafluoride in the atmosphere are studied through polyimide hollow fiber membrane with different conditions on pressure drop, gas flow and temperature. The sulfur hexafluoride concentration increased with increased pressure drop of the membrane, increased temperature and decreased non-filtrat...

  6. Preparation of hydrophilic vinyl chloride copolymer hollow fiber membranes with antifouling properties

    Science.gov (United States)

    Rajabzadeh, Saeid; Sano, Rie; Ishigami, Toru; Kakihana, Yuriko; Ohmukai, Yoshikage; Matsuyama, Hideto

    2015-01-01

    Hydrophilic vinyl chloride copolymer hollow fiber membranes with antifouling properties were prepared from brominated vinyl chloride-hydroxyethyl methacrylate copolymer (poly(VC-co-HEMA-Br)). The base membrane was grafted with two different zwitterionic monomers, (2-methacryloyloxyethylphosphorylcholine) (MPC) and [2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium hydroxide) (MEDSAH), and poly(ethylene glycol) methyl ether methacrylate (PEGMA). The effect of the grafting on the base membrane hydrophilicity and antifouling properties was investigated. For comparison of the results, the pure water permeabilities and pore sizes at the outer surfaces of the grafted hollow fiber membranes were controlled to be similar. A poly(VC-co-HEMA-Br) hollow fiber membrane with similar pure water permeability and pore size was also prepared as a control membrane. A BSA solution was used as a model fouling solution for evaluation of the antifouling properties. Grafting with zwitterionic monomers and PEGMA improved the antifouling properties compared with the control membrane. The PEGMA grafted membrane showed the best antifouling properties among the grafted membranes

  7. Green Modification of Outer Selective P84 Nanofiltration (NF) Hollow Fiber Membranes for Cadmium Removal

    KAUST Repository

    Gao, Jie

    2015-10-26

    Outer-selective thin-film composite (TFC) hollow fiber membranes are normally made from interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). However, the removal of excess MPD solution and the large consumption of alkane solvents are their technical bottlenecks. In this study, green methods to prepare the outer selective TFC hollow fiber membranes were explored by firstly modifying the membrane substrate with polyethyleneimine (PEI) and then by water soluble small molecules such as glutaraldehyde (GA) and epichlorohydrin (ECH). Using P84 polyimide as the substrate, not only do these modifications decrease substrate\\'s pore size, but also vary surface charge by making the membranes less positively charged. As a result, the resultant membranes have higher rejections against salts such as Na2SO4, NaCl and MgSO4. The PEI and then GA modified membrane has the best separation performance with a NaCl rejection over 90% and a pure water permeability (PWP) of 1.74±0.01 Lm−2bar−1h−1. It also shows an impressive rejection to CdCl2 (94%) during long-term stability tests. The CdCl2 rejection remains higher than 90% at operating temperatures from 5 to 60 °C. This study may provide useful insights for green manufacturing of outer-selective nanofiltration (NF) hollow fiber membranes.

  8. Efficient Photocatalytic Activities of TiO2 Hollow Fibers with Mixed Phases and Mesoporous Walls

    Science.gov (United States)

    Hou, Huilin; Shang, Minghui; Wang, Lin; Li, Wenge; Tang, Bin; Yang, Weiyou

    2015-10-01

    Currently, Degussa P25, with the typical mixed phases of anatase and rutile TiO2, is widely applied as the commercial photocatalysts. However, there are still some of obstacles for the P25 nanoparticles with totally high photocatalytic activities, especially for the catalytic stability due to their inevitable aggregation of the nanoparticles when used as the photocatalysts. In the present work, we reported the exploration of a novel TiO2 photocatalyst, which could offer an ideal platform for synergetic combination of the mixed-phase composition, hollow architecture and mesoporous walls for the desired excellent photocatalytic efficiency and robust stability. The mesoporous TiO2 hollow nanofibers were fabricated via a facile single capillary electrospinning technique, in which the foaming agents were used for creating mesopores throughout the walls of the hollow fibers. The obtained hollow fibers exhibit a high purity and possess the mixed phases of 94.6% anatase and 5.4% rutile TiO2. As compared to P25, the as-fabricated mesoporous TiO2 hollow fibers exhibited much higher efficient photocatalytic activities and stabilities toward the hydrogen evolution with a rate of ~499.1 μmol g-1·h-1 and ~99.5% degradation Rhodamine B (RhB) in 60 min, suggesting their promising application in efficient photocatalysts.

  9. Design of robust hollow fiber membranes with high power density for osmotic energy production

    KAUST Repository

    Zhang, Sui

    2014-04-01

    This study highlights the design strategy of highly asymmetric hollow fiber membranes that possess both characteristics of high flux and high mechanical strength to effectively reap the osmotic energy from seawater brine with an ultrahigh power density. An advanced co-extrusion technology was employed to fabricate the polyethersulfone (PES) hollow fiber supports with diversified structures from macrovoid to sponge-like. The microstructure of the supports is found critical for the stability and water permeability of the thin film composite (TFC) membranes. A high porosity in the porous layer is needed to reduce internal concentration polarization, while a thick and relatively dense skin layer underneath the TFC layer is required to maintain good mechanical stability and stress dissipation. The pore size of the supporting layer underneath the TFC layer must be small with a narrow pore size distribution to ensure the formation of a less-defective, highly permeable and mechanically stable TFC layer. The newly developed hollow fiber comprising high asymmetry, high porosity, and a thick skin layer with a small and narrow pore size distribution underneath the TFC layer produces a maximum power density of 24.3W/m2 at 20.0bar by using 1M NaCl as the concentrated brine and deionized (DI) water as the feed. The proposed design strategy for ultrahigh power density membranes clearly advances the osmotic energy production close to commercialization with a quite cost-effective and practicable approach. © 2013 Elsevier B.V.

  10. Treatment of submerged hollow fiber ultrafiltration membrane for reuse of sludge water

    Institute of Scientific and Technical Information of China (English)

    YAO Hong; SHAN Wen-guan; SUN Ming-dong; WANG Xiao-shuang

    2008-01-01

    To lower the costs of wastewater treatment, the submerged hollow fiber uhrafiltration membrane was employed to reuse the filter backwash water and settling tank sludge water. Experimental study indicates that the submerged hollow fiber uhrafiltration membrane can condense the concentration of sludge from 0. 1% -0. 3% to 2. 5%, At 20 ℃, the system can operate continuously for 80 days with daily online backwashing with chemical additions only once, and the membrane flux can be recovered up to 97% by using NaC10 and NaOH as chemi-cal additions. The results show that the membrane flux is mainly affected by temperature, and has a positive lin-ear relation to. temperature with a slope of 0. 368. After treated by submerged hollow fiber uhrafiltration mem-brane, the effluent can reach the National Standard for Drinking Water( GB5749 -85 ), especially for the sludge water from sedimentation tanks and the backwashing water from filters in water supply plants.

  11. Preparation and properties of homogeneous-reinforced polyvinylidene fluoride hollow fiber membrane

    Science.gov (United States)

    Zhang, Xuliang; Xiao, Changfa; Hu, Xiaoyu; Bai, Qianqian

    2013-01-01

    Homogeneous-reinforced (HR) polyvinylidene fluoride (PVDF) hollow fiber membranes include PVDF polymer solutions (coating layer) and the matrix membrane prepared through the dry-wet spinning process. The performance of HR membranes varies with the polymer concentration in the polymer solutions and is characterized in terms of pure water flux, rejection of protein, porosity, infiltration property, a mechanical strength test, and morphology observations by a field emission scanning electron microscope (FESEM). The results of this study indicate that the tensile strength of the HR PVDF membranes decreases slights compared with that of the matrix membrane, but the elongation at break increases much more and the hollow fiber membranes are endowed with better flexibility performance. The HR PVDF hollow fiber membranes have a favorable interfacial bonding between the coating layer and the matrix membrane, as shown by FESEM. The infiltration property is characterized by the contact angle experiments. Pure water flux decreases while the rejection ratio with an increase in polymer concentration increasing. The protein solution flux of the HR PVDF membranes is higher than that of the matrix membrane after 100 min of infiltration.

  12. Preparation and properties of homogeneous-reinforced polyvinylidene fluoride hollow fiber membrane

    International Nuclear Information System (INIS)

    Highlights: ► The homogeneous-reinforced method has been adopted firstly in preparing of PVDF membranes. ► The HR membranes have a favorable interfacial bonding between the coating layer and the matrix membrane. ► The better performance of the HR membranes in protein solution can indirectly improve the service life of membranes. - Abstract: Homogeneous-reinforced (HR) polyvinylidene fluoride (PVDF) hollow fiber membranes include PVDF polymer solutions (coating layer) and the matrix membrane prepared through the dry-wet spinning process. The performance of HR membranes varies with the polymer concentration in the polymer solutions and is characterized in terms of pure water flux, rejection of protein, porosity, infiltration property, a mechanical strength test, and morphology observations by a field emission scanning electron microscope (FESEM). The results of this study indicate that the tensile strength of the HR PVDF membranes decreases slights compared with that of the matrix membrane, but the elongation at break increases much more and the hollow fiber membranes are endowed with better flexibility performance. The HR PVDF hollow fiber membranes have a favorable interfacial bonding between the coating layer and the matrix membrane, as shown by FESEM. The infiltration property is characterized by the contact angle experiments. Pure water flux decreases while the rejection ratio with an increase in polymer concentration increasing. The protein solution flux of the HR PVDF membranes is higher than that of the matrix membrane after 100 min of infiltration.

  13. Ultem®/ZIF-8 mixed matrix hollow fiber membranes for CO2/N2 separations

    KAUST Repository

    Dai, Ying

    2012-05-01

    Organic-inorganic hybrid (mixed matrix) membranes can potentially extend the separation performance of traditional polymeric materials while maintaining processing convenience. Although many dense films studies have been reported, there have been few reported cases of these materials being successfully extended to asymmetric hollow fibers. In this work we report the first successful production of mixed matrix asymmetric hollow fiber membranes containing metal-organic-framework (MOF) ZIF-8 fillers. Specifically, we have incorporated ZIF-8 into a polyetherimide (Ultem ® 1000) matrix and produced dual-layer asymmetric hollow fiber membranes via the dry jet-wet quench method. The outer separating layer of these composite fibers contains 13wt% (17vol%) of ZIF-8 filler. These membranes have been tested over a range of temperatures and pressures for a variety of gas pairs. An increase in separation performance for the CO 2/N 2 gas pairs was observed for both pure gas and mixed gas feeds. © 2012 Elsevier B.V.

  14. Nitrogen removal by granular nitritation-anammox in an upflow membrane-aerated biofilm reactor.

    Science.gov (United States)

    Li, Xiaojin; Sun, Shan; Badgley, Brian D; Sung, Shihwu; Zhang, Husen; He, Zhen

    2016-05-01

    The nitritation-anammox process has been a promising nitrogen removal technology towards sustainable wastewater treatment, but its application in treating domestic wastewater with relatively low ammonium concentrations (mainstream) remains a great challenge. In this study, an innovative lab-scale upflow membrane-aerated biofilm reactor (UMABR) was employed to treat a synthetic wastewater containing 70 mg N L(-1) ammonium. With a DO level at 0.6 ± 0.1 mg O2 L(-1) and HRT of 32 h, the effluent ammonium concentration was 4.8 ± 2.0 mg N L(-1). Increasing the nitrogen loading rate from 52.4 to 104.8 g N m(-3) d(-1) with stepwise decreasing HRT from 32 to 16 h resulted in an average TN removal efficiency of 81% without nitrite accumulation. The average observed NO3(-)-N (residue)/NH4(+)-N (consumed) ratio of 8% was below the "theoretical ratio" of 13% and further reduction of nitrate residue needs to be addressed. Fluorescence in situ hybridization (FISH) and high-throughput sequencing analyses showed the coexistence of anammox bacteria and ammonium-oxidizing bacteria (AOB) in both biofilm and granular samples. Anammox bacteria accounted for up to 63.3% of the microbial community of the granules, with Candidatus Jettenia being the distinctly dominant anammox genus. In contrast, the biofilm contained abundant Nitrosomonadaceae (AOB, 33.1%). In addition, the brown-yellow granules exhibited a more balanced community structure with anammox bacteria and AOB accounting for 33.7% and 18.2%, respectively, which may contribute to the long-term operation of single-stage nitritation-anammox process. These results demonstrate that the nitritation-anammox UMABR could potentially be used for nitrogen removal from mainstream in some specific regions with relatively warm temperature. PMID:26921710

  15. Bench Scale Thin Film Composite Hollow Fiber Membranes for Post-Combustion Carbon Dioxide Capture

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Paul [General Electric Global Research, Niskayuna, NY (United States); Bhandari, Dhaval [General Electric Global Research, Niskayuna, NY (United States); Narang, Kristi [General Electric Global Research, Niskayuna, NY (United States); McCloskey, Pat [General Electric Global Research, Niskayuna, NY (United States); Singh, Surinder [General Electric Global Research, Niskayuna, NY (United States); Ananthasayanam, Balajee [General Electric Global Research, Niskayuna, NY (United States); Howson, Paul [General Electric Global Research, Niskayuna, NY (United States); Lee, Julia [General Electric Global Research, Niskayuna, NY (United States); Wroczynski, Ron [General Electric Global Research, Niskayuna, NY (United States); Stewart, Frederick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Orme, Christopher [Idaho National Lab. (INL), Idaho Falls, ID (United States); Klaehn, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); McNally, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rownaghi, Ali [Georgia Inst. of Technology, Atlanta, GA (United States); Lu, Liu [Georgia Inst. of Technology, Atlanta, GA (United States); Koros, William [Georgia Inst. of Technology, Atlanta, GA (United States); Goizueta, Roberto [Georgia Inst. of Technology, Atlanta, GA (United States); Sethi, Vijay [Western Research Inst., Laramie, WY (United States)

    2015-04-01

    GE Global Research, Idaho National Laboratory (INL), Georgia Institute of Technology (Georgia Tech), and Western Research Institute (WRI) proposed to develop high performance thin film polymer composite hollow fiber membranes and advanced processes for economical post-combustion carbon dioxide (CO2) capture from pulverized coal flue gas at temperatures typical of existing flue gas cleanup processes. The project sought to develop and then optimize new gas separations membrane systems at the bench scale, including tuning the properties of a novel polyphosphazene polymer in a coating solution and fabricating highly engineered porous hollow fiber supports. The project also sought to define the processes needed to coat the fiber support to manufacture composite hollow fiber membranes with high performance, ultra-thin separation layers. Physical, chemical, and mechanical stability of the materials (individual and composite) towards coal flue gas components was considered via exposure and performance tests. Preliminary design, technoeconomic, and economic feasibility analyses were conducted to evaluate the overall performance and impact of the process on the cost of electricity (COE) for a coal-fired plant including capture technologies. At the onset of the project, Membranes based on coupling a novel selective material polyphosphazene with an engineered hollow fiber support was found to have the potential to capture greater than 90% of the CO2 in flue gas with less than 35% increase in COE, which would achieve the DOE-targeted performance criteria. While lab-scale results for the polyphosphazene materials were very promising, and the material was incorporated into hollow-fiber modules, difficulties were encountered relating to the performance of these membrane systems over time. Performance, as measured by both flux of and selectivity for CO2 over other flue gas constituents was found to deteriorate over time, suggesting a system that was

  16. Thermally moderated hollow fiber sorbent modules in rapidly cycled pressure swing adsorption mode for hydrogen purification

    KAUST Repository

    Lively, Ryan P.

    2012-10-01

    We describe thermally moderated multi-layered pseudo-monolithic hollow fiber sorbents entities, which can be packed into compact modules to provide small-footprint, efficient H2 purification/CO2 removal systems for use in on-site steam methane reformer product gas separations. Dual-layer hollow fibers are created via dry-jet, wet-quench spinning with an inner "active" core of cellulose acetate (porous binder) and zeolite NaY (69 wt% zeolite NaY) and an external sheath layer of pure cellulose acetate. The co-spun sheath layer reduces the surface porosity of the fiber and was used as a smooth coating surface for a poly(vinyl-alcohol) post-treatment, which reduced the gas permeance through the fiber sorbent by at least 7 orders of magnitude, essentially creating an impermeable sheath layer. The interstitial volume between the individual fibers was filled with a thermally-moderating paraffin wax. CO2 breakthrough experiments on the hollow fiber sorbent modules with and without paraffin wax revealed that the "passively" cooled paraffin wax module had 12.5% longer breakthrough times than the "non-isothermal" module. The latent heat of fusion/melting of the wax offsets the released latent heat of sorption/desorption of the zeolites. One-hundred rapidly cycled pressure swing adsorption cycles were performed on the "passively" cooled hollow fiber sorbents using 25 vol% CO2/75 vol% He (H2 surrogate) at 60 °C and 113 psia, resulting in a product purity of 99.2% and a product recovery of 88.1% thus achieving process conditions and product quality comparable to conventional pellet processes. Isothermal and non-isothermal dynamic modeling of the hollow fiber sorbent module and a traditional packed bed using gPROMS® indicated that the fiber sorbents have sharper fronts (232% sharper) and longer adsorbate breakthrough times (66% longer), further confirming the applicability of the new fiber sorbent approach for H2 purification. © 2012, Hydrogen Energy Publications, LLC

  17. Alkalinity and pH effects on nitrification in a membrane aerated bioreactor: an experimental and model analysis.

    Science.gov (United States)

    Shanahan, John W; Semmens, Michael J

    2015-05-01

    A nitrifying biofilm was grown in a laboratory-scale membrane aerated bioreactor (MABR) to calibrate and test a one-dimensional biofilm model incorporating chemical equilibria to calculate local pH values. A previously developed model (Shanahan and Semmens, 2004) based upon AQUASIM was modified to incorporate the impact of local pH changes within the biofilm on the kinetics of nitrification. Shielded microelectrodes were used to measure the concentration profiles of dissolved oxygen, ammonium, nitrate, and pH within the biofilm and the overlying boundary layer under actual operating conditions. Operating conditions were varied to assess the impact of bicarbonate loading (alkalinity), ammonium loading, and intra-membrane oxygen partial pressure on biofilm performance. Nitrification performance improved with increased ammonium and bicarbonate loadings over the range of operating conditions tested, but declined when the intra-membrane oxygen partial pressure was increased. Minor discrepancies between the measured and predicted concentration profiles within the biofilm were attributed to changes in biofilm density and vertical heterogeneities in biofilm structure not accounted for by the model. Nevertheless, predicted concentration profiles within the biofilm agreed well with experimental results over the range of conditions studied and highlight the fact that pH changes in the biofilm are significant especially in low alkalinity waters. The influent pH and buffer capacity of a wastewater may therefore have a significant impact on the performance of a membrane-aerated bioreactor with respect to nitrification, and nitrogen removal. PMID:25703659

  18. Determining the optimal transmembrane gas pressure for nitrification in membrane-aerated biofilm reactors based on oxygen profile analysis.

    Science.gov (United States)

    Wang, Rongchang; Xiao, Fan; Wang, Yanan; Lewandowski, Zbigniew

    2016-09-01

    The goal of this study was to investigate the effect of transmembrane gas pressure (P g) on the specific ammonium removal rate in a membrane-aerated biofilm reactor (MABR). Our experimental results show that the specific ammonium removal rate increased from 4.98 to 9.26 gN m(-2) day(-1) when P g increased from 2 to 20 kPa in an MABR with a biofilm thickness of approximately 600 μm. However, this improvement was not linear; there was a threshold of P g separating the stronger and weaker effects of P g. The ammonium removal rate was improved less significantly when P g was over the threshold, indicating that there is an optimal threshold of P g for maximizing ammonium removal in an MABR. The change in oxygen penetration depth (d p) is less sensitive to P g in the ammonia-oxidizing active layer than in the inactive layer in membrane-aerated biofilm. The location of the P g threshold is at the same point as the thickness of the active layer on the curve of d p versus P g; thus, the active layer thickness and the optimal P g can be determined on the basis of the changes in the slope of d p to P g. PMID:27170321

  19. Outer-selective thin film composite (TFC) hollow fiber membranes for osmotic power generation

    KAUST Repository

    Le, Ngoc Lieu

    2016-01-14

    The pressure-retarded osmosis (PRO) process is a green technique for power generation to respond the world\\'s need of energy sustainability. In this study, we have developed the vital component of the process, i.e. membrane, in the configuration of the outer-selective thin-film composite (TFC) hollow fiber, which is more practical than other configurations in the real applications. The support layer morphology and the formation of the selective polyamide layer have been optimized for a good PRO performance. The results show that the bore fluid with higher amount of the solvent N-methyl-2-pyrrolidone leads to full finger-like hollow fibers, which provide higher flux but lower pressure tolerance. The addition of higher amount of diethylene glycol into the dope solution, improves the pore formation and suppresses the macrovoid formation, while properly lowering the take-up speed increases their wall thickness and pressure tolerance. A simple alcohol-pre-wetting approach on the fiber support leads to a smooth and thin polyamide layer, which is favorable for a high water flux and power density. Its efficiency follows this order: n-propanol>ethanol>methanol>water. The n-propanol pre-wetted TFC membrane can tolerate 17 bar with a peak power density of 9.59 W/m2 at room temperature, using 1 M NaCl solution as the draw solution and DI water as feed. This work demonstrates the potential of outer-selective TFC hollow fiber membranes for energy conversion via PRO process, provides useful database to fabricate suitable support morphology and raise a simple technique to practically form a thin and smooth polyamide layer.

  20. Hollow fiber vs. flat sheet MBR for the treatment of high strength stabilized landfill leachate.

    Science.gov (United States)

    Hashisho, J; El-Fadel, M; Al-Hindi, M; Salam, D; Alameddine, I

    2016-09-01

    The Membrane Bioreactor (MBR) technology is increasingly becoming a prominent process in the treatment of high-strength wastewater such as leachate resulting from the decomposition of waste in landfills. This study presents a performance comparative assessment of flat sheet and hollow fiber membranes in bioreactors for the treatment of relatively stable landfill leachate with the objective of defining guidelines for pilot/full scale plants. For this purpose, a laboratory scale MBR system was constructed and operated to treat a leachate with Chemical Oxygen Demand (COD) (3900-7800mg/L), Biochemical Oxygen Demand (BOD5) (∼440-1537mg/L), Total Phosphorus (TP) (∼10-59mg/L), Phosphate (PO4(3)(-)) (5-58mg/L), Total Nitrogen (TN) (1500-5200mg/L), and ammonium (NH4(+)) (1770-4410mg/L). Both membranes achieved comparable BOD (92.2% vs. 93.2%) and TP (79.4% vs. 78.5%) removals. Higher PO4(3)(-) removal efficiency or percentage (87.3% vs. 81.3%) and slightly higher, but not statistically significant, COD removal efficiency were obtained with the hollow fiber membrane (71.4% vs. 68.5%). On the other hand, the flat sheet membrane achieved significantly higher TN and NH4(+) removal efficiencies (61.2% vs. 49.4% and 63.4% vs. 47.8%, respectively), which may be attributed to the less frequent addition of NaOCl compared to the hollow fiber system. PMID:26775757

  1. A validated CFD model to predict O₂ and CO₂ transfer within hollow fiber membrane oxygenators.

    Science.gov (United States)

    Hormes, Marcus; Borchardt, Ralf; Mager, Ilona; Rode, Thomas Schmitz; Behr, Marek; Steinseifer, Ulrich

    2011-03-01

    Hollow fiber oxygenators provide gas exchange to and from the blood during heart surgery or lung recovery. Minimal fiber surface area and optimal gas exchange rate may be achieved by optimization of hollow fiber shape and orientation (1). In this study, a modified CFD model is developed and validated with a specially developed micro membrane oxygenator (MicroMox). The MicroMox was designed in such a way that fiber arrangement and bundle geometry are highly reproducible and potential flow channeling is avoided, which is important for the validation. Its small size (V(Fluid)=0.04 mL) allows the simulation of the entire bundle of 120 fibers. A non-Newtonian blood model was used as simulation fluid. Physical solubility and chemical bond of O₂ and CO₂ in blood was represented by the numerical model. Constant oxygen partial pressure at the pores of the fibers and a steady state flow field was used to calculate the mass transport. In order to resolve the entire MicroMox fiber bundle, the mass transport was simulated for symmetric geometry sections in flow direction. In vitro validation was achieved by measurements of the gas transfer rates of the MicroMox. All measurements were performed according to DIN EN 12022 (2) using porcine blood. The numerical simulation of the mass transfer showed good agreement with the experimental data for different mass flows and constant inlet partial pressures. Good agreement could be achieved for two different fiber configurations. Thus, it was possible to establish a validated model for the prediction of gas exchange in hollow fiber oxygenators. PMID:21462147

  2. Hollow fiber-supported designer ionic liquid sponges for post-combustion CO2 scrubbing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, JS; Hillesheim, PC; Huang, DK; Lively, RP; Oh, KH; Dai, S; Koros, WJ

    2012-11-30

    A proof of concept study for a new type of carbon capture system is considered for post-combustion CO2 capture based on porous hollow fiber sorbents with ionic liquids sorbed in the cell walls of the fiber. This study proves that delicate morphological features in the open-celled porous wall can be maintained during the infusion process. Mixtures of task specific ionic liquid (i.e. [BMIM][Tf2N]) and superbase (i.e. DBU) were loaded into polyamide-imide (PAI) fibers by a so-called two-step non-solvent infusion protocol. In the protocol, methanol carries ionic liquids into the pore cell walls of hollow fibers and then hexane carries superbase to create an efficient CO2 sorbent. Our ionic liquid/superbase impregnation technique overcomes a serious increase in mass transfer resistance upon reaction with CO2, thereby allowing its large scale utilization for post-combustion CO2 capture. The investigation on the effect of different pore former additives (different molecular weights of polyvinylpyrrolidone, lithium nitrate, and their mixtures) suggested that a large molecular weight of PVP (M-w; 1300k) including dope composition produces highly interconnected open cell pore structures of PAI hollow fibers. Lastly, a lumen side barrier layer was successfully formed on the bore side of neat PAI fibers by using a mixture of Neoprene (R) with crosslinking agents (TSR-633) via a post-treatment process. The lumen layer will enable heat removal from the fiber sorbents during their application in rapid thermal swing cycling processes. (C) 2012 Elsevier Ltd. All rights reserved.

  3. Charged micropollutant removal with hollow fiber nanofiltration membranes based on polycation/polyzwitterion/polyanion multilayers.

    Science.gov (United States)

    de Grooth, Joris; Reurink, Dennis M; Ploegmakers, Jeroen; de Vos, Wiebe M; Nijmeijer, Kitty

    2014-10-01

    Hollow fiber nanofiltration membranes can withstand much higher foulant concentrations than their spiral wound counterparts and can be used in water purification without pretreatment. Still, the preparation of hollow fiber nanofiltration membranes is much less established. In this work, we demonstrate the design of a hollow fiber nanofiltration membrane with excellent rejection properties by alternatively coating a porous ultrafiltration membrane with a polycation, a polyzwitterion, and a polyanion. On model surfaces, we show, for the first time, that the polyzwitterion poly N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine (PSBMA) can be incorporated into traditional polyelectrolyte multilayers based on poly(styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC). Furthermore, work on model surfaces allows a good characterization of, and insight into, the layer build-up and helps to establish the optimal membrane coating conditions. Membranes coated with these multilayers have high salt rejection of up to 42% NaCl, 72% CaCl2, and 98% Na2SO4 with permeabilities of 3.7-4.5 l·m(-2)·h(-1)·bar(-1). In addition to the salt rejections, the rejection of six distinctively different micropollutants, with molecular weights between 215 and 362 g·mol(-1), was investigated. Depending on the terminating layer, the incorporation of the polyzwitterion in the multilayer results in nanofiltration membranes that show excellent retentions for both positively and negatively charged micropollutants, a behavior that is attributed to dielectric exclusion of the solutes. Our approach of combining model surfaces with membrane performance measurements provides unique insights into the properties of polyzwitterion-containing multilayers and their applications. PMID:25203928

  4. Development of Hollow Fiber Carbon Membranes for CO2 Separation

    OpenAIRE

    He, Xuezhong

    2011-01-01

    CO2 capture from flue gases by membrane technology in post combustion power plants could be used for the reducing of CO2 emissions. Previous work has demonstrated that the carbon membrane can achieve a high separation performance with respect to high CO2 permeability and selectivity over the other gases, such as N2 and O2. The focus of the current work was to find a low-cost precursor and develop a simple process for the preparation of high performance hollow fiber carbon membranes (HFCMs) fo...

  5. PEBAX®/PAN Hollow Fiber Membranes for CO2/CH4 Separation

    Czech Academy of Sciences Publication Activity Database

    Esposito, E.; Clarizia, G.; Bernardo, P.; Jansen, J. C.; Sedláková, Zuzana; Izák, Pavel; Curcio, S.; de Cindio, B.; Tasselli, F.

    2015-01-01

    Roč. 94, SI (2015), s. 53-61. ISSN 0255-2701. [International Congress of Chemical and Process Engineering CHISA 2014 /21./ and Conference PRES 2014 /17./. Prague, 23.08.2014-27.08.2014] R&D Projects: GA ČR GA14-12695S Grant ostatní: INRP(IT) MicroPERLA:PON01_01840 Institutional support: RVO:67985858 Keywords : composite membrane * hollow fibers * CO2/CH4 separation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.071, year: 2014

  6. Hollow fiber supported liquid membrane technology: possible applications in the radioactive waste management

    International Nuclear Information System (INIS)

    Hollow fiber supported liquid membrane (HFSLM) technology development work was carried out at Radiochemistry Division, BARC for possible applications in the back end of the nuclear fuel cycle. Some of the studies carried out included 'actinide partitioning' using TODGA, lanthanide - actinide separation using Cyanex-301 and Cs recovery from waste using Calix-crown-6. The physical stability of HFSLM was reasonably good during continuous operation for over 120 h. Radiolytic stability of hollow fibre module up to 500 KGy dose was also satisfactory. (author)

  7. Recovery of uranium from medium active acidic wastes using hollow fiber contactor

    International Nuclear Information System (INIS)

    The permeation of U(VI) in presence of fission products has been studied from medium active acidic waste employing 30% tributyl phosphate (TBP) as a carrier through hollow fiber supported liquid membrane (HFSLM). The parameters like carrier concentration, effect of metal ion concentration and flow rate were studied. The result reveals that higher metal ion concentration in feed phase gives higher flux for permeation. Higher flow rate and 30% carrier concentration yield > 90% recovery of U(VI) in 0.1 M NH2OH.HCl in 0.3 M HNO3 as strippant. Recovery could be further enhanced by using fresh strippant. (author)

  8. A simulation model for transient response of a gas separation module using a hollow fiber membrane

    International Nuclear Information System (INIS)

    A simulation model has been developed for transient response of a gas separation module using a hollow fiber membrane for the removal of tritium from the atmosphere of the confinement space. The mass transfer process such as sorption and desorption of gases at the surface of the dense layer and the porous support layer, diffusive transfer in the both layers are treated in the model. Sorption isotherm, mass transfer rate and permeance are estimated through step-wise transient response experiments. The present model represents well not only separation factors and recovery ratio at the steady state but also responses to the multi-step wise change in the sweep gas rate.

  9. Experimental study on generation of high energy few cycle pulses with hollow fiber filled with neon

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    25 fs pulses with energy up to 0.8 mJ from a multi-pass amplifier system have been spectrally broadened from 460 nm to 950 nm due to strong self-phase modulation(SPM) effect in a gas filled hollow fiber.Using a set of chirped mirrors,the ul-tra-broadband dispersion compensation was achieved,and the compressed pulses reached their transform limit.Under optimized conditions we achieved pulses with duration of 5.1 fs and with energy of 400 μJ,corresponding to the peak power up to 80 GW.

  10. Effect of Polyvinylidene Fluoride Hollow Fiber Membranes on Mass Transfer of Samarium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of swelling and stripping acidity on the mass transfer coefficient based on water phase and the inner diameters of membranes were studied with P507-HCl-Sm as working system in the two different kinds of hollow fiber membranes. Effects of extractant concentration, H+ concentration in aqueous phase and Sm3+ concentration on extraction rate were discussed and the corresponding reaction series were obtained. According to the investigations on the interfacial kinetics, the reaction kinetics equation and reaction rate constant were obtained.

  11. Plasticization-resistant hollow fiber membranes for CO2/CH4 separation based on a thermally crosslinkable polyimide

    KAUST Repository

    Chen, Chien-Chiang

    2011-10-01

    Decarboxylation-induced thermal crosslinking has been demonstrated to be effective for stabilizing membranes against plasticization in dense films. This study extends this promising crosslinking approach from dense films to industrially relevant asymmetric hollow fiber membranes. Crosslinkable asymmetric hollow fiber membranes were spun from a carboxylic acid containing polyimide, 6FDA-DAM:DABA. Dope and spinning conditions were optimized to obtain fibers with a defect-free selective skin layer. It is found that slightly defective fibers suffered severe selectivity loss after thermal crosslinking, suggesting that defect-free property is essential to the performance of the resulting crosslinked hollow fiber membranes. The crosslinked fibers were tested for CO 2/CH 4 separation. The excellent plasticization resistance under high pressure feeds (with highest CO 2 partial pressure of 400psia) suggests that these robust membranes are promising for aggressive natural gas purification. © 2011 Elsevier B.V.

  12. Poly(ethyleneimine) infused and functionalized Torlon®-silica hollow fiber sorbents for post-combustion CO2 capture

    KAUST Repository

    Li, Fuyue Stephanie

    2014-03-01

    Organic-inorganic hybrid materials functionalized with amine-containing reagents are emerging as an important class of materials for capturing carbon dioxide from flue gas. Polymeric silica hollow fiber sorbents are fabricated through the proven dry-jet/wet-quench spinning process. In our study, a new technique for functionalizing polymeric silica hollow fiber sorbents with poly(ethyleneimine), followed by a post-spinning infusion step was studied. This two step process introduces a sufficient amount of poly(ethyleneimine) to the polymeric silica hybrid material support to improve the CO2 sorption capacity due to the added amine groups. The poly(ethyleneimine) infused and functionalized hollow fiber sorbents are also characterized by a thermal gravimetric analyzer (TGA) to assess their CO2 sorption capacities. © 2014 Elsevier Ltd. All rights reserved.

  13. Rapid Start-up and Loading of an Attached Growth, Simultaneous Nitrification/Denitrification Membrane Aerated Bioreactor

    Science.gov (United States)

    Meyer, Caitlin E.; Pensinger, Stuart; Pickering, Karen D.; Barta, Daniel; Shull, Sarah A.; Vega, Letticia M.; Christenson, Dylan; Jackson, W. Andrew

    2015-01-01

    Membrane aerated bioreactors (MABR) are attached-growth biological systems used for simultaneous nitrification and denitrification to reclaim water from waste. This design is an innovative approach to common terrestrial wastewater treatments for nitrogen and carbon removal and implementing a biologically-based water treatment system for long-duration human exploration is an attractive, low energy alternative to physiochemical processes. Two obstacles to implementing such a system are (1) the "start-up" duration from inoculation to steady-state operations and (2) the amount of surface area needed for the biological activity to occur. The Advanced Water Recovery Systems (AWRS) team at JSC explored these two issues through two tests; a rapid inoculation study and a wastewater loading study. Results from these tests demonstrate that the duration from inoculation to steady state can be reduced to under two weeks, and that despite low ammonium removal rates, the MABRs are oversized.

  14. Effect of polymer viscosities on the fiber structure and membrane properties of polypropylene/polyethylene bicomponent hollow fibers

    Science.gov (United States)

    Sugiura, Satoshi; Takarada, Wataru; Kikutani, Takeshi

    2015-05-01

    Polypropylene (PP) / Polyethylene (PE) bicomponent microporous hollow fiber membranes were prepared through the bicomponent melt spinning and drawing processes. Fibers of hollow shape were firstly prepared through the melt spinning process by introducing the air into the core part of the fiber cross-section. Annealing and drawing processes were applied to thus prepared fibers to furnish the membrane properties to the fibers. In this study, high and low molecular weight PP, HMwPP and LMwPP, were used. Viscosity of HMwPP was higher than that of PE, while viscosity of LMwPP was lower than that of PE. In the case of LMwPP/PE fibers, birefringence of PE component increased with take-up velocity and birefringence of LMwPP component was lower than that of PE component at all attainable take-up velocities. In HMwPP/PE fibers, birefringence of both components increased with take-up velocity at low take-up velocities. Birefringence of HMwPP component increased continuously with further increase of take-up velocity, however that of PE component decreased significantly at the take-up velocity higher than 1 km/min. In this region, birefringence of HMwPP component in HMwPP/PE bicomponent hollow fibers was much higher than that of LMwPP component in LMwPP/PE hollow fibers. Hollow fiber membrane which was prepared by annealing and drawing of HMwPP/PE hollow fibers showed 10 times higher air transmission rate than that of LMwPP/PE fibers. In addition, air transmission rate increased with an increase in the HMwPP composition. These results indicate that the structure of PP component in the as-spun fiber undertake a crucial role on membrane properties in PP/PE bicomponent hollow fiber membrane.

  15. Transport of strontium cation through a hollow fiber supported dichlorobenzene membrane using 18-C-6 crown ether. Nitrate and anion of dinonylnaphtalen sulfonic acid

    International Nuclear Information System (INIS)

    The transport of strontium cation through a hollow fiber supported dichlorobenzene membrane using 18-C-6 crown ether, nitrate and anion of dinonylnaphtalen sulfonic acid has been studied. A permeation device-single hollow fiber module with on-line radiometric detection of strontium using 85Sr tracer was used, (author). 5 refs., 7 figs., 1 tab

  16. Passive coherent combining of CEP-stable few-cycle pulses from a temporally divided hollow fiber compressor.

    Science.gov (United States)

    Jacqmin, Hermance; Jullien, Aurélie; Mercier, Brigitte; Hanna, Marc; Druon, Frédéric; Papadopoulos, Dimitrios; Lopez-Martens, Rodrigo

    2015-03-01

    We demonstrate a simple and robust passive coherent combining technique for temporal compression of millijoule energy laser pulses down to few-cycle duration in a gas-filled hollow fiber. High combining efficiency is achieved by using carefully oriented calcite plates for temporal pulse division and recombination. Carrier-envelope phase (CEP)-stable, 6-fs, 800-nm pulses with more than 0.6 mJ energy are routinely generated. This method could aid in the energy scaling of CEP-stable hollow-fiber compressor systems. PMID:25723413

  17. Extraction of zirconium from simulated acidic nitrate waste using liquid membrane in hollow fiber contactor

    International Nuclear Information System (INIS)

    The acidic waste raffinate stream of zirconium (Zr) purification plant contains about 2 gpl of Zr in about 2M free nitric acid. TBP, which is the most commonly used solvent in the nuclear industry, is not suitable for the extraction of Zr from this lean solution as its distribution coefficient is less than one. In house synthesized Mixed Alkyl Phosphine Oxide (MAPO) is a potential extractant for Zr from this lean stream. Intensification of this process for recovery of Zr has been attempted through use of efficient contactor, namely, hollow fiber module and efficient process, namely, simultaneous extraction and stripping across liquid membrane containing MAPO. Based on batch equilibrium studies selection of suitable concentration of extractant, composition of diluent, selection and concentration of strippant for the proposed liquid membrane system was made. The selected organic and strippant concentration was used to study suitability of application of Dispersion Liquid Membrane (DLM) in hollow fiber contactor for recovery Zr from solution simulated to Zr plant raffinate. Challenges related to stable operation of the liquid membrane system like stability of the organic phase in the micropores of lumen and stability of the dispersion during the pertraction were addressed through pressure balance across the lumen and choice of adequate dispersion condition respectively. (author)

  18. Characterization of Thermally Cross-Linkable Hollow Fiber Membranes for Natural Gas Separation

    KAUST Repository

    Chen, Chien-Chiang

    2013-01-23

    The performance of thermally cross-linkable hollow fiber membranes for CO2/CH4 separation and the membrane stability against CO2 plasticization was investigated. The fiber membranes were thermally cross-linked at various conditions. Cross-linking temperature was found to have a significant effect, while shorter soak time and the presence of trace oxidizer (O2 or N2O) had a negligible effect. The cross-linked fibers were tested using high CO2 content feeds (50-70% CO2) at a variety of feed pressures (up to 1000 psia), temperatures, and permeate pressures (up to 100 psia) to evaluate membrane performance under various realistic operating conditions. The results demonstrated that cross-linking improves membrane selectivity and effectively eliminates swelling-induced hydrocarbon loss at high pressures. Excellent stability under aggressive feeds (with CO2 partial pressure up to 700 psia) suggests that cross-linked hollow fiber membranes have great potential for use in diverse aggressive applications, even beyond the CO2/CH4 example explored in this work. © 2012 American Chemical Society.

  19. A novel theoretical model for mass transfer of hollow fiber hemodialyzers

    Institute of Scientific and Technical Information of China (English)

    DING Weiping; HE Liqun; ZHAO Gang; SHU Zhiquan; CHENG Shuxia; GAO Dayong

    2003-01-01

    A novel theoretical model for mass transfer of hollow fiber bundles inhemodialyzers is presented. In the model, a hemodialyzer is considered as a porous zone which is composed of two non-interpenetrating porous flow zones. Firstly, the dialysate side (shell side) is thought as a porous medium zone. Then by solidifying the dialysate flow zone and the occupied zone by hollow fiber membrane, the rest zone of hemodialyzer (i.e. blood side or lumen side) is considered as a porous medium zone too. Finally, the interface of the two flow zones is the fiber membrane through which mass transfer is performed. The dialysate and bloodflows are all described by Navier-Stokes equations with Darcy momentum source terms. Kedem-Katchalsky equations as other source terms are added into Navier-Stokes equations to simulate the permeating flux through the membrane. All equations must be coupled together in the process of computing. The model is validated by the experimental data in literature. The simulative results show that the predicted clearances agree well with the experimental data, and the model in this paper is better than other models for the forecast of clearance.

  20. Synthesis and applications of diethylstilbestrol-based molecularly imprinted polymer-coated hollow fiber tube.

    Science.gov (United States)

    Liu, Meihua; Li, Meijin; Qiu, Bin; Chen, Xi; Chen, Guonan

    2010-03-17

    A novel molecularly imprinted polymer-coated polypropylene hollow fiber tube (MIP-HFT) was photoinitiated for the copolymerization of diethylstilbestrol (DES) as a template molecule, alpha-methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a crosslinking agent. The characteristics and applications of the MIP-HFT were investigated. In order to compare its characteristics with those of a non-imprinted polymer-immersed hollow fiber tube, the selectivity of the MIP-HFT was investigated using dienestrol and hexestrol as the structural analogues of a DES template, and phenol and methylbenzene were taken as reference compounds. The MIP-HFT was employed in the HPLC analysis of spiked milk samples. The detection limits of the method were found to be in the range 2.5-3.3microgL(-1) for DES, dienestrol and hexestrol and the RSD% were in the range 6.4-8.9. The limits of quantitation were found to be in the range 8.7-9.4microgL(-1) in milk for DES, dienestrol and hexestrol, and their average recoveries were 83.7-90.6% in the spiked milk samples. The experimental results revealed that the MIP-HFT provides a good carrier for the selective adsorption of DES and its chemical structure analogs, and can be used for the preconcentration of these compounds in complicated samples. PMID:20172093

  1. Tri-bore PVDF hollow fibers with a super-hydrophobic coating for membrane distillation

    KAUST Repository

    Lu, Kang-Jia

    2016-04-26

    Membranes with good mechanical strength, high vapor flux and outstanding anti-wetting properties are essential for membrane distillation (MD) applications. In this work, porous polyvinylidene fluoride (PVDF) tri-bore hollow fiber membranes with super-hydrophobicity are developed to achieve these desired properties. The tri-bore hollow fiber offers better mechanical strength than the conventional single-bore fiber. To improve its anti-wetting properties, Teflon® AF 2400 is coated on the membrane surface. The effects of coating on membrane morphology, performance and anti-wetting properties have been thoroughly investigated. With an optimal coating condition (0.025 wt% of Teflon® AF 2400, 30 s), a super-hydrophobic surface with a contact angle of 151o is achieved. The resultant membrane shows an increase of 109% in liquid entry pressure (LEP) with a slight sacrifice of 21% in flux. Long term direct contact MD tests have confirmed that the Teflon® AF 2400 coated membrane has enhanced stability with an average flux of 21 kg m-2 h-1 and rejection of 99.99% at 60 °° C for desalination application.

  2. Mathematic Model of Unsteady Penetration Mass Transfer in Randomly Packed Hollow Fiber Membrane Module

    Institute of Scientific and Technical Information of China (English)

    张秀莉; 张泽廷; 张卫东; 郝欣

    2004-01-01

    Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.

  3. Surface Plasmon Resonance Sensor Based on Ethylene Tetra-Fluoro-Ethylene Hollow Fiber

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-11-01

    Full Text Available A new kind of hollow fiber surface plasmon resonance sensor (HF-SPRS based on the silver-coated ethylene tetra-fluoro-ethylene (ETFE hollow fiber (HF is presented. The ETFE HF-SPRS is fabricated, and its performance is investigated experimentally by measuring the transmission spectra of the sensor when filled by liquid sensed media with different refractive indices (RIs. Theoretical analysis based on the ray transmission model is also taken to evaluate the sensor. Because the RI of ETFE is much lower than that of fused silica (FSG, the ETFE HF-SPRS can extend the lower limit of the detection range of the early reported FSG HF-SPRS from 1.5 to 1.42 approximately. This could greatly enhance the application potential of HF-SPRS. Moreover, the joint use of both ETFE and FSG HF-SPRSs can cover a wide detection range from 1.42 to 1.69 approximately with high sensitivities larger than 1000 nm/RIU.

  4. Hollow Fiber Bioreactors for In Vivo-like Mammalian Tissue Culture

    Science.gov (United States)

    Storm, Michael P.; Sorrell, Ian; Shipley, Rebecca; Regan, Sophie; Luetchford, Kim A.; Sathish, Jean; Webb, Steven; Ellis, Marianne J.

    2016-01-01

    Tissue culture has been used for over 100 years to study cells and responses ex vivo. The convention of this technique is the growth of anchorage dependent cells on the 2-dimensional surface of tissue culture plastic. More recently, there is a growing body of data demonstrating more in vivo-like behaviors of cells grown in 3-dimensional culture systems. This manuscript describes in detail the set-up and operation of a hollow fiber bioreactor system for the in vivo-like culture of mammalian cells. The hollow fiber bioreactor system delivers media to the cells in a manner akin to the delivery of blood through the capillary networks in vivo. The system is designed to fit onto the shelf of a standard CO2 incubator and is simple enough to be set-up by any competent cell biologist with a good understanding of aseptic technique. The systems utility is demonstrated by culturing the hepatocarcinoma cell line HepG2/C3A for 7 days. Further to this and in line with other published reports on the functionality of cells grown in 3-dimensional culture systems the cells are shown to possess increased albumin production (an important hepatic function) when compared to standard 2-dimensional tissue culture. PMID:27285826

  5. Response surface methodology to evaluation the recovery of amylases by hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    João Baptista Severo Júnior

    2007-07-01

    Full Text Available This work aimed to study the pH and the transmembrane pressure effects during the recovery of alpha and beta amylases enzymes from corn malt (Zea mays by hollow fiber membrane. The optimal condition was obtained for a statistical model, established by response surface methodology (RSM. The response surface analysis showed that the best operation condition for amylolitics enzymes recovery by hollow fiber membrane was 0.05 bar and pH 5.00, while the enzymes were purified about of 26 times.Este trabalho objetivou estudar o efeito do pH e da pressão trans-membrana durante a recuperação das enzimas alfa e beta amilases do malte de milho (Zea mays por membranas de fibras ocas, a obtenção das condições ótimas foi feita por um modelo estatístico, estabelecido pela metodologia de superfície de resposta (RSM. A análise da superfície de resposta mostrou que as melhores condições operacionais para a recuperação das enzimas amiloliticas por membranas de fibras ocas foi 0,05 bar e pH 5,00; onde as enzimas foram purificadas cerca de 26 vezes.

  6. Fabrication of nanocrystalline hydroxyapatite doped degradable composite hollow fiber for guided and biomimetic bone tissue engineering

    International Nuclear Information System (INIS)

    Natural bone tissue possesses a nanocomposite structure interwoven in a three-dimensional (3-D) matrix, which plays critical roles in conferring appropriate physical and biological properties to the bone tissue. Single type of material may not be sufficient to mimic the composition, structure and properties of native bone, therefore, composite materials consisting of both polymers, bioceramics, and other inorganic materials have to be designed. Among a variety of candidate materials, polymer-nanoparticle composites appear most promising for bone tissue engineering applications because of superior mechanical properties, improved durability, and surface bioactivity when compared with conventional polymers or composites. The long term objective of this project is to use highly aligned, bioactive, biodegradable scaffold mimicking natural histological structure of human long bone, and to engineer and regenerate human long bone both in vitro and in vivo. In this study, bioactive, degradable, and highly permeable composite hollow fiber membranes (HFMs) were fabricated using a wet phase phase-inversion approach. The structure of the hollow fiber membranes was examined using scanning electron microscopy (SEM); degradation behavior was examined using weigh loss assay, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC); and bioactivity was evaluated with the amount of calcium deposition from the culture media onto HFM surface. Doping PLGA HFMs with nanoHA results in a more bioactive and slower degrading HFM than pure PLGA HFMs

  7. Autohydrogenotrophic denitrification of drinking water using a polyvinyl chloride hollow fiber membrane biofilm reactor

    International Nuclear Information System (INIS)

    A hollow fiber membrane biofilm reactor (MBfR) using polyvinyl chloride (PVC) hollow fiber was evaluated in removing nitrate form contaminated drinking water. During a 279-day operation period, the denitrification rate increased gradually with the increase of influent nitrate loading. The denitrification rate reached a maximum value of 414.72 g N/m3 d (1.50 g N/m2 d) at an influent NO3--N concentration of 10 mg/L and a hydraulic residence time of 37.5 min, and the influent nitrate was completely reduced. At the same time, the effluent quality analysis showed the headspace hydrogen content (3.0%) was lower enough to preclude having an explosive air. Under the condition of the influent nitrate surface loading of 1.04 g N/m2d, over 90% removal efficiencies of the total nitrogen and nitrate were achieved at the hydrogen pressure above 0.04 MPa. The results of denaturing gel gradient electrophoresis (DGGE), 16S rDNA gene sequence analysis, and hierarchical cluster analysis showed that the microbial community structures in MBfR were of low diversity, simple and stable at mature stages; and the beta-Proteobacteria, including Rhodocyclus, Hydrogenophaga, and beta-Proteobacteria HTCC379, probably play an important role in autohydrogenotrophic denitrification.

  8. Polyimide hollow fiber membranes for CO2 separation from wet gas mixtures

    Directory of Open Access Journals (Sweden)

    F. Falbo

    2014-12-01

    Full Text Available Matrimid®5218 hollow fiber membranes were prepared using the dry-wet spinning process. The transport properties were measured with pure gases (H2, CO2, N2, CH4 and O2 and with a mixture (30% CO2 and 70% N2 in dry and wet conditions at 25 ºC, 50 ºC, 60 ºC and 75 ºC and up to 600 kPa. Interesting values of single gas selectivity up to 60 ºC (between 31 and 28 for CO2/N2 and between 33 and 30 for CO2/CH4 in dry condition were obtained. The separation factor measured for the mixture was 20% lower compared to the single gas selectivity, in the whole temperature range analyzed. In saturation conditions the data showed that water influences the performance of the membranes, inducing a reduction of the permeance of all gases. Moreover, the presence of water caused a decrease of single gas selectivity and separation factor, although not so significant, highlighting the very high water resistance of hollow fiber membrane modules.

  9. Continuous preparation of polymer coated drug crystals by solid hollow fiber membrane-based cooling crystallization.

    Science.gov (United States)

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

    2016-02-29

    A facile way to continuously coat drug crystals with a polymer is needed in controlled drug release. Conventional polymer coating methods have disadvantages: high energy consumption, low productivity, batch processing. A novel method for continuous polymer coating of drug crystals based on solid hollow fiber cooling crystallization (SHFCC) is introduced here. The drug acting as the host particle and the polymer for coating are Griseofulvin (GF) and Eudragit RL100, respectively. The polymer's cloud point temperature in its acetone solution was determined by UV spectrophotometry. An acetone solution of the polymer containing the drug in solution as well as undissolved drug crystals in suspension were pumped through the tube side of the SHFCC device; a cold liquid was circulated in the shell side to rapidly cool down the feed solution-suspension in the hollow-fiber lumen. The polymer precipitated from the solution and coated the suspended crystals due to rapid temperature reduction and heterogeneous nucleation; crystals formed from the solution were also coated by the polymer. Characterizations by scanning electron microscopy, thermogravimetric analysis, laser diffraction spectroscopy, X-ray diffraction, Raman spectroscopy, and dissolution tests show that a uniformly coated, free-flowing drug/product can be obtained under appropriate operating conditions without losing the drug's pharmaceutical properties and controlled release characteristics. PMID:26772536

  10. Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

    KAUST Repository

    Bettahalli, N.M. Srivatsa

    2016-04-26

    Dehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

  11. High-speed recovery of germanium in a convection-aided mode using functional porous hollow-fiber membranes.

    Science.gov (United States)

    Ozawa, I; Saito, K; Sugita, K; Sato, K; Akiba, M; Sugo, T

    2000-08-01

    A porous hollow-fiber membrane capable of recovery of germanium from a liquid stream was prepared by radiation-induced graft polymerization of an epoxy-group-containing vinyl monomer, glycidyl methacrylate, and subsequent functionalization with 2,2'-iminodiethanol, di-2-propanolamine, N-methylglucamine, and 3-amino-1,2-propanediol. The functional group density was as high as 1.4 mol per kg of the resultant hollow fiber. The polymer chains containing functional groups surrounding the pores enabled a high-speed recovery of germanium during permeation of a germanium oxide (GeO2) solution through the pores of the hollow fiber. Because of a negligible diffusional mass-transfer resistance, germanium concentration changes with the effluent volume, i.e., breakthrough curves, overlapped irrespective of the residence time of the solution, which ranged from 0.37 to 3.7 s across the hollow fiber. After repeated use of adsorption and elution, the adsorption capacity did not deteriorate. PMID:10949471

  12. Transport of uranium from nitric acid solution by non-dispersive solvent extraction using a hollow fiber contactor

    International Nuclear Information System (INIS)

    Transport behaviour of uranium from nitric acid medium was investigated using hollow fiber non-dispersive extraction technique. The effect of feed acidity and carrier concentration was studied in counter current mode at a feed flow rate of 3.5 mL/s and an organic phase flow rate of 4.5 mL/s. (author)

  13. Pseudo-emulsion based hollow fiber strip dispersion technique: a novel application with U(VI)-TBP system

    International Nuclear Information System (INIS)

    The aim of this paper is to evaluate the effect of various chemical and hydrodynamic parameters to optimize performance of PEHFSD for U(VI) from nitric acid medium and also to provide a novel, stable hollow fiber supported liquid membrane (HFSLM) system which removes the uranium from process effluents

  14. Effect of vapor- and liquid-phase radiation grafting on water permeability of porous hollow-fiber membrane

    International Nuclear Information System (INIS)

    Effect of the radiation-induced graft polymerization of monomers in vapor and liquid phases to the hollow-fiber membrane microfilter, made of porous high density polyethylene, upon the permeability of water has been studied. Determination of the flux of hollow-fiber membranes prepared by the graft polymerization of acrylonitrile, vinyl acetate, styrene, or acrylic acid revealed that the membranes prepared by vapor-phase grafting had a higher flux than those prepared by liquid-phase grafting. The measurement of pore volume and dimensional change revealed that hollow-fiber membrane grafted in vapor phase swells to larger extent. Cyano group of acrylonitrile and acetoxyl group of vinyl acetate, grafted to hollow-fiber membrane were converted to amide oxime and alcoholic hydroxyl group, respectively by the chemical modification. The flux of these functionalized membranes were determined and it is found that the functionalized membranes derived from vapor-phase grafted membrane had higher water permeability than those derived from liquid-phase grafted ones. (author)

  15. Evaluation of hollow fiber and mini perm bioreactors as an alternative to murine ascites for small scale monoclonal antibody production

    International Nuclear Information System (INIS)

    The objective of this study was to compare monoclonal antibody production in hollow fiber, mini perm bioreactor systems and murine ascites to determine the feasibility of the bioreactor system as a potential alternative to the use of mice. One hybridoma cell line was grown in hollow fiber, mini perm bioreactor systems and in groups of 5 mice. Mice were primed with 0.5 ml pristane intraperitoneally 14 days prior to inoculation of 1x107 hybridoma cells. Each mouse was tapped a maximum of three times for collection of ascites. Bioreactors were harvested three times weekly for 30 days and were monitored by cell counts, cell viability and media consumption. Time and materials logs were maintained. The total quantity of monoclonal antibody produced in 5 mice versus the total production for the two different bioreactors (hollow fiber and mini perm) in 30 days was as follows: cell line 2AC10E6C7 produce 158 mg vs.97.5 mg, vs 21.54 mg respectively. Mean monoclonal antibody concentration ranged from 4.07 to 8.37 mg/ml in murine ascites, from 0.71 to 3.8 mg/ml in hollow fiber bioreactor system, and from 0.035 to 1.06 in mini perm. Although time and material costs were generally greater for the bioreactors, these results suggest that hollow fiber and mini perm bioreactor systems merit further investigations as potentially viable in vitro alternatives to the use of mice for small scale (<1mg) monoclonal antibody production.(Author)

  16. Evaluation of Hollow Fiber And Miniperm Bioreactors as An Alternative to Murine Ascites for Small Scale Monoclonal Antibody Production

    International Nuclear Information System (INIS)

    The objective of this study was to compare monoclonal antibody production in hollow fiber, miniPERM bioreactor systems and murine ascites to determine the feasibility of the bioreactor system as a potential alternative to the use of mice. One hybridoma cell line was grown in hollow fiber, miniPERM bioreactor systems and in groups of 5 mice. Mice were primed with 0.5 ml pristane intraperitoneally 14 days prior to inoculation of 1X107 hybridoma cells. Each mouse was tapped a maximum of three times for collection of ascites. Bioreactors were harvested three times weekly for 30 days and were monitored by cell counts, cell viability and media consumption. Time and materials logs were maintained. The total quantity of monoclonal antibody produced in 5 mice versus the total production for the two different bioreactors (hollow fiber and miniPERM) in 30 days was as follows: cell line 2AC10E6C7 produce 158 mg vs.97.5 mg; vs 21.54 mg respectively. Mean monoclonal antibody concentration ranged from 4.07 to 8.37 mg/ml in murine ascites, from 0.71 to 3.8 mg/ml in hollow fiber bioreactor system, and from 0.035 to 1.06 in miniPERM. Although time and material costs were generally greater for the bioreactors, these results suggest that hollow fiber and miniPERM bioreactor systems merit further investigations as potentially viable in vitro alternatives to the use of mice for small scale (< 1 g) monoclonal antibody production.

  17. Fabrication and Characterization of Polymeric Hollow Fiber Membranes with Nano-scale Pore Sizes

    International Nuclear Information System (INIS)

    Porous polyvinylidene fluoride (PVDF) and polysulfide (PSF) hollow fiber membranes were fabricated via a wet spinning method. The membranes were characterized in terms of gas permeability, wetting pressure, overall porosity and water contact angle. The morphology of the membranes was examined by FESEM. From gas permeation test, mean pore sizes of 7.3 and 9.6 nm were obtained for PSF and PVDF membrane, respectively. Using low polymer concentration in the dopes, the membranes demonstrated a relatively high overall porosity of 77 %. From FESEM examination, the PSF membrane presented a denser outer skin layer, which resulted in significantly lower N2 permeance. Therefore, due to the high hydrophobicity and nano-scale pore sizes of the PVDF membrane, a good wetting pressure of 4.5x10-5 Pa was achieved. (author)

  18. Modeling and parametric analysis of hollow fiber membrane system for carbon capture from multicomponent flue gas

    KAUST Repository

    Khalilpour, Rajab

    2011-08-12

    The modeling and optimal design/operation of gas membranes for postcombustion carbon capture (PCC) is presented. A systematic methodology is presented for analysis of membrane systems considering multicomponent flue gas with CO 2 as target component. Simplifying assumptions is avoided by namely multicomponent flue gas represented by CO 2/N 2 binary mixture or considering the co/countercurrent flow pattern of hollow-fiber membrane system as mixed flow. Optimal regions of flue gas pressures and membrane area were found within which a technoeconomical process system design could be carried out. High selectivity was found to not necessarily have notable impact on PCC membrane performance, rather, a medium selectivity combined with medium or high permeance could be more advantageous. © 2011 American Institute of Chemical Engineers (AIChE).

  19. Effect of Heat Transfer Coefficient on the Temperature Gradient for Hollow Fiber

    Institute of Scientific and Technical Information of China (English)

    王华平; 余晓蔚; 杨崇倡; 胡学超; 庄毅

    2001-01-01

    The heat transfer coefficient h caused by blowing affects the heat transfer of fiber greatly. Especially,unsymmetrical blowing forms the unsymmetrical temperature gradient on the fiber cross.section. Based on the results of spinning simulation by computer, the changes of heat transfer coefficient on the cross-section along the spinning line and the effects on distributions of temperature gradients were discussedl It is showed that for the spinning simulation of hollow fiber under strong blowing condition, the heat transfer coetticient should bemodified as: h=0.437×10-4[ G/Vρ ( R2/ R2-n2 ) ] -o.333(V2+ 64( VYsin (θ))2)0.167

  20. Mechanism of Fe crud deposition by membrane electrification in hollow fiber membrane filter

    International Nuclear Information System (INIS)

    The hollow fiber membrane filter (HFF) applied to the condensate polishing system in BWR plants occasionally experiences a greater pressure drop due to fouling of the membrane inner surface. Then a mechanism for fouling and its countermeasures were studied from simulated laboratory experiments. The HFF made of polyethylene polymer which has a dielectric property became negatively charged on its surface when pure water, such as condensate, flowed through the filter. The degree of the negative charge depended on the water electrical conductivity and flow velocity through the membrane. The amount of Fe hydroxide deposits on the membrane surface depended on the Fe and Cu ion concentrations. Then a crud precoating method was confirmed as an effective and practicable means to restrict deposits. (author)

  1. A pseudobiospecific hollow fiber cartridge for in vitro adsorption of autoantibodies from pathological serum

    Directory of Open Access Journals (Sweden)

    Ventura R.C.A.

    2000-01-01

    Full Text Available The affinity filtration technique using histidine as a pseudobiospecific ligand immobilized on poly(ethylene vinyl alcohol hollow fiber membranes (His-PEVA was used to remove autoantibodies from serum of patients with autoimmune disease. The effects of buffering solution conditions on the efficiency of autoantibodies removal was studied. The removal of anti-dsDNA, anti-SS-A/Ro, anti-Sm, anti-Sm/RNP and anti-cardiolipin autoantibodies present in the serum was investigated, comparing the efficiency between Hepes and Tris-HCl buffers. The results showed the potential of the membrane to remove all the autoantibodies studied. Anti SS-A/Ro was removed more efficiently in Tris-HCl buffer system rather than with the Hepes buffer.

  2. Hollow-Fiber Flow Field-Flow Fractionation for Mass Spectrometry: From Proteins to Whole Bacteria

    Science.gov (United States)

    Reschiglian, Pierluigi; Zattoni, Andrea; Rambaldi, Diana Cristina; Roda, Aldo; Hee Moon, Myeong

    Mass spectrometry (MS) provides analyte identification over a wide molar-mass range. However, particularly in the case of complex matrices, this ability is often enhanced by the use of pre-MS separation steps. A separation, prototype technique for the "gentle" fractionation of large/ultralarge analytes, from proteins to whole cells, is here described to reduce complexity and maintain native characteristics of the sample before MS analysis. It is based on flow field-flow fractionation, and it employs a micro-volume fractionation channel made of a ca. 20 cm hollow-fiber membrane of sub-millimeter section. The key advantages of this technique lie in the low volume and low-cost of the channel, which makes it suitable to a disposable usage. Fractionation performance and instrumental simplicity make it an interesting methodology for in-batch or on-line pre-MS treatment of such samples.

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

    International Nuclear Information System (INIS)

    The transport behavior of Nd(III) was investigated using hollow-fiber supported liquid membranes (HFSLM) from an acidic feed solution using N,N,N',N'-tetraoctyl-diglycolamide (TODGA) in normal paraffinic hydrocarbon (NPH) as the carrier. Near quantitative transport (>99%) of Nd(III) from 500 mL of feed containing 1 g/L Nd in 3.5 M HNO3 was possible in about 45 minutes. Quantitative transport time increased when the volume or Nd(III ) concentration in the feed was increased. The liquid membrane had excellent stability as indicated by eight consecutive runs that gave consistent transport rates. The HFSLM data using Cyanex- 301 in n-dodecane as carrier extractant for the lanthanide-actinide separation with the feed solution 1 M NaNO3 at pH 3.5 and stripping solution 0.01 M EDTA at a pH 3.5 were promising. (authors)

  4. Polyethersulfone hollow fiber modified with poly(styrenesulfonate) and Pd nanoparticles for catalytic reaction

    Science.gov (United States)

    Emin, C.; Gu, Y.; Remigy, J.-C.; Lahitte, J.-F.

    2015-07-01

    The aim of this work is the synthesis of polymer-stabilized Pd nanoparticles (PdNP) inside a functionalized polymeric porous membrane in order to develop hybrid catalytic membrane reactors and to test them in model metal-catalyzed organic reactions. For this goal, a polymeric membrane support (Polyethersulfone hollow fiber-shaped) was firstly functionalized with an ionogenic polymer (i.e. poly(styrenesulfonate) capable to retain PdNP precursors using an UV photo-grafting method. PdNP were then generated inside the polymeric matrix by chemical reduction of precursor salts (intermatrix synthesis). The catalytic performance of the PdNP catalytic membranes was evaluated using reduction of nitrophenol by sodium borohydride (NaBH4) in water.

  5. Hollow Fiber Spacesuit Water Membrane Evaporator Development and Testing for Advanced Spacesuits

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis; Tsioulos, Gus; Settles, Joseph; Colunga, Aaron; Vogel, Matthew; Vonau, Walt

    2010-01-01

    Grant Bue and Matthew Vogel presented the two types of Spacesuit Water Membrane Evaporators (SWME) that were developed based on hydrophobic microporous membranes. One type, the Sheet Membrane (SaM) SWME, is composed of six concentric Teflon sheet membranes fixed on cylindrical-supporting screens to form three concentric annular water channels. Those water channels are surrounded by vacuum passages to draw off the water vapor that passes through the membrane. The other type, the Hollow Fiber (HoFi) SWME, is composed of more than 14,000 tubes. Water flows through the tubes and water vapor passes through the tube wall to the shell side that vents to the vacuum of space. Both SWME types have undergone testing to baseline the performance at predicted operating temperatures and flow rates; the units also have been subjected to contamination testing and other conditions to test resiliency.

  6. Numerical Simulation and Analysis of CO2 Removal in a Polypropylene Hollow Fiber Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Zhien Zhang

    2014-01-01

    Full Text Available This present study shows a comprehensive 2D numerical model for removal of CO2 in a polypropylene (PP hollow fiber membrane contactor (HFMC using the computational fluid dynamics (CFD method. Monoethanolamine (MEA solution was used as the liquid absorbent in a nonwetting mode. The simulation results represented that higher liquid velocity and concentration and lower gas velocity and concentration led to higher percent of CO2 removal. The most proper parameters for CO2 removal were less than 1 mol m−3 gas concentration and 0.2 m s−1 gas flow rate, and for MEA the values were above 8 mol m−3 concentration and approximately 1 m s−1 liquid velocity. Furthermore, the model was validated with the experiment results. Therefore, the modeling results provided references to the selection of absorbents and operation parameters in the experimental study and pilot-scale applications.

  7. Solvent recovery from soybean oil/n-hexane mixtures using hollow fiber membrane

    Directory of Open Access Journals (Sweden)

    M. V. Tres

    2012-09-01

    Full Text Available In this work, the separation of refined soybean oil/n-hexane mixtures was investigated using a commercial hollow fiber ultrafiltration membrane 50 kDa. Three alcohols with different chain lengths were tested for the conditioning of the membrane; n-propyl alcohol showed the highest n-hexane permeate flux after conditioning. There was a decrease in the rejection and an increase in permeate flux over time. This behavior may be related to swelling and membrane plasticization by the oil. Rejections from 10.0 to 28.7% and total permeate fluxes from 12.2 to 65.3 kg/m²h were observed. An increase in the oil/n-hexane mass ratio and the pressure caused an increase in the rejection and permeate total flux for most assays. No degradation was observed in the membrane module.

  8. Toluene impurity effects on CO2 separation using a hollow fiber membrane for natural gas

    KAUST Repository

    Omole, Imona C.

    2011-03-01

    The performance of defect-free cross-linkable polyimide asymmetric hollow fiber membranes was characterized using an aggressive feed stream containing up to 1000ppm toluene. The membrane was shown to be stable against toluene-induced plasticization compared with analogs made from Matrimid®, a commercial polyimide. Permeation and sorption analysis suggest that the introduction of toluene vapors in the feed subjects the membrane to antiplasticization, as the permeance decreases significantly (to less than 30%) under the most aggressive conditions tested. Separation efficiencies reflected by permselectivities were less affected. The effect of the toluene on the membrane was shown to be reversible when the toluene was removed. © 2010 Elsevier B.V.

  9. A Pilot-Scale System for Carbon Molecular Sieve Hollow Fiber Membrane Manufacturing

    KAUST Repository

    Karvan, O.

    2012-12-21

    Carbon molecular sieve (CMS) membranes offer advantages over traditional polymeric membrane materials, but scale-up of manufacturing systems has not received much attention. In the recent decade, there has been a dramatic increase in fundamental research on these materials with a variety of applications being studied. The results from a pilot-scale CMS production system are presented. This system was designed based on extensive laboratory research, and hollow fiber membranes produced in this system show similar performance compared to membranes produced using a smaller bench-scale system. After optimizing the system design, a 93% recovery of the precursor fibers for use in membrane module preparation were obtained. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Simulation Study on Separation of Cobalt and Nickel Using Multi-Hollow Fiber Supported Liquid Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Woo; Oh, Byung Keun; Youn, In Ju; Lee, Won Hong [Department of Chemical Engineering, Sogang University, Seoul (Korea); Cho, Kyung Sang [IBM T. J. Waston Research Center, Yorktown (United States)

    2001-05-01

    Selective separation of cobalt ion from a feed solution, which contains cobalt and nickel ions, using a multi-stage hollow fiber supported liquid membrane (HFSLM) process with recirculation was analyzed to evaluate the design parameters. Mathematical models based on mass balance of a fully developed and a laminar flow in a cylindrical geometry were established. The model equations could be solved by using an orthogonal collocation technique. The effect of various operating conditions such as pH in the feed phase, carrier composition, nickel ion concentration, circulation flow rate and recirculation ratio was simulated. The optimum operating conditions for the highest flux and separation factor of cobalt ion were determined by the simulation results. 15 refs., 12 figs., 1 tab.

  11. Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

    International Nuclear Information System (INIS)

    Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10−6 cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts

  12. Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Pagán, Ángel E.; Kang, Yunqing [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Findlay, Michael W. [Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA (United States); University of Melbourne Department of Surgery, Royal Melbourne Hospital, Parkville, VIC (Australia); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States)

    2015-04-01

    Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10{sup −6} cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts.

  13. Analysis of flux reduction behaviors of PRO hollow fiber membranes: Experiments, mechanisms, and implications

    KAUST Repository

    Xiong, Jun Ying

    2016-01-15

    Pressure retarded osmosis (PRO) is a promising technology to harvest renewable osmotic energy using a semipermeable membrane. However, a significant flux reduction has been always observed that severely shrinks the harvestable power to a level only marginally higher or even lower than the economically feasible value. This work focuses on the elucidation of various underlying mechanisms responsible for the flux reduction. First, both inner-selective and outer-selective thin film composite (TFC) hollow fiber membranes are employed to examine how the fundamental internal factors (such as the surface salinity of the selective layer at the feed side (CF,m) and its components) interact with one another under the fixed bulk salinity gradient, resulting in various behaviours of external performance indexes such as water flux, reverse salt flux, and power density. Then, the research is extended to investigate the effects of the growing bulk feed salinity due to the accumulated reverse salt flux along PRO modules. Finally, the insights obtained from the prior two stationary conditions are combined with the advanced nucleation theory to elucidate the dynamic scaling process by visualizing how the multiple fundamental factors (such as local supersaturation, nucleation rate and nuclei size) evolve and interplay with one another in various membrane regimes during the whole scaling process. To our best knowledge, it is the first time that the advanced nucleation theory is applied to study the PRO scaling kinetics in order to provide subtle and clear pictures of the events occurring inside the membrane. This study may provide useful insights to design more suitable TFC hollow fiber membranes and to operate them with enhanced water flux so that the PRO process may become more promising in the near future.

  14. Process Performance and Bacterial Community Structure Under Increasing Influent Disturbances in a Membrane-Aerated Biofilm Reactor.

    Science.gov (United States)

    Tian, Hailong; Yan, Yingchun; Chen, Yuewen; Wu, Xiaolei; Li, Baoan

    2016-02-01

    The membrane-aerated biofilm reactor (MABR) is a promising municipal wastewater treatment process. In this study, two cross-flow MABRs were constructed to explore the carbon and nitrogen removal performance and bacterial succession, along with changes of influent loading shock comprising flow velocity, COD, and NH4-N concentrations. Redundancy analysis revealed that the function of high flow velocity was mainly embodied in facilitating contaminants diffusion and biosorption rather than the success of overall bacterial populations (p > 0.05). In contrast, the influent NH4-N concentration contributed most to the variance of reactor efficiency and community structure (p < 0.05). Pyrosequencing results showed that Anaerolineae, and Beta- and Alphaproteobacteria were the dominant groups in biofilms for COD and NH4-N removal. Among the identified genera, Nitrosomonas and Nitrospira were the main nitrifiers, and Hyphomicrobium, Hydrogenophaga, and Rhodobacter were the key denitrifiers. Meanwhile, principal component analysis indicated that bacterial shift in MABR was probably the combination of stochastic and deterministic processes. PMID:26528534

  15. Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

    Science.gov (United States)

    Coutts, Janelle L.; Lunn, Griffin M.; Koss, Lawrence L.; Hummerick, Mary E.; Spencer, Lachelle E.; Johnsey, Marissa N.; Richards, Jeffrey T.; Ellis, Ronald; Birmele, Michele N.; Wheeler, Raymond M.

    2014-01-01

    Bioreactor research is mostly limited to continuous stirred-tank reactors (CSTRs) which are not an option for microgravity (g) applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. Bioreactors and filtration systems for treating wastewater in g could avoid the need for harsh pretreatment chemicals and improve overall water recovery. Solution: Membrane Aerated Bioreactors (MABRs) for g applications, including possible use for wastewater treatment systems for the International Space Station (ISS).

  16. Transport of strontium and some 1. and 2. group's cations through hollow fiber supported liquid membranes using crowns

    International Nuclear Information System (INIS)

    Models which describe the permeation of strontium cation through liquid membranes are shown in this paper. Partition coefficients have been determined radiometrically, using Sr-85 tracer. The results were treated according to the theory developed by Danesi using simple equation. The permeation of Sr2+ using 18-crown-6 crown ether (18C6) and picric acid in bulk liquid toluene membrane systems with and without surface/active substances (SPAN 80, ECA 4360) has been studied. The transport of Sr2+ using 18-C-6 ether as a carrier and picrate as a co-counter ion through hollow fiber supported dichlorobenzene liquid membrane has been studied too. A polypropylene hollow fiber ACCUREL PP type S6/ENKA and a permeation device with a single hollow fiber module with on-line radiometric detection of strontium using Sr-85 tracer, was used. This type of permeation system has shown reproducible results, fast and effective permeation. Results prove the possible mechanism of strontium cation transport though liquid membrane. Another subject of study was the transport of metal ions (Ca2+, Sr2+, Ba2+, Na+, K+, Cs+) using (18C6) as a carrier and picrate as co/counter ion through hollow fiber supported dichlorobenzene liquid membrane using capillary isotachophoresis (ITP) measurement of the cations concentration. The experimental results obtained using ITP method for Sr2+ concentration determination are in good agreement with those obtained by on-line radiometric detection using Sr-85 tracer, under the same conditions (feed, membrane, strip, hollow fiber and the same pertraction device). The ITP method could be successfully used for analyses of samples containing a mixture of all separated cations. The results of this study indicate that the polypropylene hollow fiber supported dichlorobenzene membrane is suitable for studied metal cation transport using 18C6 as a carrier and a picrate as co-counter ion. This combination enables fast and effective cation separation. The pertraction module

  17. A Modified EPA Method 1623 that Uses Tangential Flow Hollow-Fiber Ultrafiltration and Heat Dissociation Steps to Detect Waterborne Cryptosporidum and Giardia spp.

    Science.gov (United States)

    This protocol describes the use of a tangential flow hollow-fiber ultrafiltration sample concentration system and a heat dissociation as alternative steps for the detection of waterborne Cryptosporidium and Giardia species using EPA Method 1623.

  18. DEMONSTRATION OF PILOT-SCALE PERVAPORATION SYSTEMS FOR VOLATILE ORGANIC COMPOUND REMOVAL FROM A SURFACTANT ENHANCED AQUIFER REMEDIATION FLUID. II. HOLLOW FIBER MEMBRANE MODULES

    Science.gov (United States)

    Pilot-scale demonstration of pervaporation-based removal of volatile organic compounds from a surfactant enhanced aquifer remediation (SEAR) fluid has been conducted at USEPA's Test & Evaluation Facility using hollow fiber membrane modules. The membranes consisted of microporous...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.

    1994-08-04

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

  1. High temperature sensitivity fiber sensor based on M-Z interferometer fabricated by suspended dual-core hollow fiber

    Science.gov (United States)

    Zeng, Hongyi; Geng, Tao; Yang, Wenlei; An, Maowei; Yang, Fan

    2015-10-01

    We successfully fabricate and demonstrate a type of in-line M-Z interferometer by using single mode fiber and suspended dual-core hollow fiber. We fuse one section of dual-core hollow fiber (about 5-10cm length used as interferometer arms) with two part of single mode fiber by arc discharging on their cross sections. After this new M-Z interferometer's fabrication and related experiments, we improved it by absorbing drops of alcohol in its dual-core hollow body which can do much of contributions to its sensitivity. With bunches of temperature experiments conducted, we find this new interferometer has a good temperature sensitivity highly as 1.751nm/°C (from 20 to 100 °C) and interferometer with alcohol inside has a better temperature sensitivity highly as 3.015nm/ °C (from 20 to 60 °C) respectively.

  2. Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation

    Directory of Open Access Journals (Sweden)

    Pereira C.C.

    2000-01-01

    Full Text Available During hollow fiber spinning many variables are involved whose effects are still not completely clear. However, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. In this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. It was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. The effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. According to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.

  3. Development of a High Performance PES Ultrafiltration Hollow Fiber Membrane for Oily Wastewater Treatment Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Noor Adila Aluwi Shakir

    2015-12-01

    Full Text Available This study attempts to optimize the spinning process used for fabricating hollow fiber membranes using the response surface methodology (RSM. The spinning factors considered for the experimental design are the dope extrusion rate (DER, air gap length (AGL, coagulation bath temperature (CBT, bore fluid ratio (BFR, and post-treatment time (PT whilst the response investigated is rejection. The optimal spinning conditions promising the high rejection performance of polyethersulfone (PES ultrafiltration hollow fiber membranes for oily wastewater treatment are at the dope extrusion rate of 2.13 cm3/min, air gap length of 0 cm, coagulation bath temperature of 30 °C, and bore fluid ratio (NMP/H2O of 0.01/99.99 wt %. This study will ultimately enable the membrane fabricators to produce high-performance membranes that contribute towards the availability of a more sustainable water supply system.

  4. Highly robust thin-film composite pressure retarded osmosis (PRO) hollow fiber membranes with high power densities for renewable salinity-gradient energy generation.

    Science.gov (United States)

    Han, Gang; Wang, Peng; Chung, Tai-Shung

    2013-07-16

    The practical application of pressure retarded osmosis (PRO) technology for renewable blue energy (i.e., osmotic power generation) from salinity gradient is being hindered by the absence of effective membranes. Compared to flat-sheet membranes, membranes with a hollow fiber configuration are of great interest due to their high packing density and spacer-free module fabrication. However, the development of PRO hollow fiber membranes is still in its infancy. This study aims to open up new perspectives and design strategies to molecularly construct highly robust thin film composite (TFC) PRO hollow fiber membranes with high power densities. The newly developed TFC PRO membranes consist of a selective polyamide skin formed on the lumen side of well-constructed Matrimid hollow fiber supports via interfacial polymerization. For the first time, laboratory PRO power generation tests demonstrate that the newly developed PRO hollow fiber membranes can withstand trans-membrane pressures up to 16 bar and exhibit a peak power density as high as 14 W/m(2) using seawater brine (1.0 M NaCl) as the draw solution and deionized water as the feed. We believe that the developed TFC PRO hollow fiber membranes have great potential for osmotic power harvesting. PMID:23772898

  5. Application of hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction techniques in analytical toxicology

    OpenAIRE

    Vahid Sharifi; Ali Abbasi; Anahita Nosrati

    2016-01-01

    The recent developments in hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction are reviewed. Applications of these newly emerging developments in extraction and preconcentration of a vast category of compounds including heavy metals, pesticides, pharmaceuticals and abused drugs in complex matrices (environmental and biological matrices) are reviewed and discussed. The new developments in these techniques including the use of solvents lighter than water, ioni...

  6. Transport of neodymium from nitric acid solution by non-dispersive solvent extraction using a hollow fiber contactor

    International Nuclear Information System (INIS)

    Transport behaviour of neodymium from nitric acid medium was investigated using hollow fiber non-dispersive extraction technique employing a mixture of di-nonyl phenyl phosphoric acid (DNPPA) and tri-n-octylphosphine oxide (TOPO) in petrofin as the solvent. The effect of feed acidity and Nd concentration was studied in counter current mode at a feed as well as organic phase flow rate of 100 mL/min. (author)

  7. Feasibility Study of Advanced NOM-Reduction by Hollow Fiber Ultrafiltration and Nanofiltration at a Swedish Surface Water Treatment Plant

    OpenAIRE

    Angelica Lidén; Persson, Kenneth M.

    2016-01-01

    Membrane technology, i.e., ultrafiltration and nanofiltration, is growing in popularity, as it is a space efficient alternative for surface water treatment. Two types of hollow fiber membranes were tested in a fully equipped and automated pilot at a Swedish water treatment plant. Raw water was treated by a nanofilter and by coagulation before an ultrafilter. Operation parameters recorded during these trials have been the basis for cost estimations and assessments of environmental impact, comp...

  8. Extraction kinetics of uranium(VI) with di(2-ethylhexyl) phosphoric acid using a hollow fiber membrane extractor

    International Nuclear Information System (INIS)

    The kinetics of solvent extraction of U(VI) with di(2-ethylhexyl) phosphoric acid (HDEHP) using a microporous hydrophobic hollow fiber membrane extractor has been investigated. The effects of U(VI) and hydrogen ion concentrations in aqueous phase, HDEHP concentration in organic phase, flow velocities of aqueous and organic phase and temperature on extraction rate of U(VI) were examined. The experimental results suggest that the extraction rate of U(VI) is controlled by diffusion. (author)

  9. Selective interfacial synthesis of metal-organic frameworks on a polybenzimidazole hollow fiber membrane for gas separation

    Science.gov (United States)

    Biswal, Bishnu P.; Bhaskar, Anand; Banerjee, Rahul; Kharul, Ulhas K.

    2015-04-01

    Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability.Metal-organic frameworks (MOFs) have gained immense attention as new age materials due to their tuneable properties and diverse applicability. However, efforts on developing promising materials for membrane based gas separation, and control over the crystal growth positions on polymeric hollow fiber membranes still remain key challenges. In this investigation, a new, convenient and scalable room temperature interfacial method for growing MOFs (ZIF-8 and CuBTC) on either the outer or inner side of a polybenzimidazole based hollow fiber (PBI-BuI-HF) membrane surface has been achieved in a controlled manner. This was made possible by the appropriate selection of an immiscible solvent pair and the synthetic conditions. The growth of MOFs on the PBI-BuI-HF membrane by the interfacial method was continuous and showed an appreciable gas separation performance, conveying promise for their applicability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00299k

  10. Diffusion and Inhibition Processes in a Hollow-fiber Membrane Bioreactor for Hybridoma Culture. Development of a Mathematical Model

    OpenAIRE

    Legazpi, L.; Collado, S. (Santiago); Laca, A.; Díaz, M.

    2016-01-01

    The performance of a hollow-fiber membrane bioreactor (HFBR) (molecular weight cut-off 30 kD, fiber surface area 2050 cm2) containing a culture of hybridoma cells has been investigated. Experimental data were used as basis to develop a model of general application. Concentrations of fundamental nutrients (glucose and glutamine), inhibitory products (ammonium and lactate), and monoclonal antibodies (MAb) against bovine lactoferrin (IgG1) were monitored over time. Exchange of nutrients and p...

  11. Moxifloxacin's Limited Efficacy in the Hollow-Fiber Model of Mycobacterium abscessus Disease.

    Science.gov (United States)

    Ferro, Beatriz E; Srivastava, Shashikant; Deshpande, Devyani; Pasipanodya, Jotam G; van Soolingen, Dick; Mouton, Johan W; van Ingen, Jakko; Gumbo, Tawanda

    2016-06-01

    Current regimens used to treat pulmonary Mycobacterium abscessus disease have limited efficacy. There is an urgent need for new drugs and optimized combinations and doses. We performed hollow-fiber-system studies in which M. abscessus was exposed to moxifloxacin lung concentration-time profiles similar to human doses of between 0 and 800 mg/day. The minimum bactericidal concentration and MIC were 8 and 2 mg/liter, respectively, in our M. abscessus strain, suggesting bactericidal activity. Measurement of the moxifloxacin concentrations in each hollow-fiber system revealed an elimination rate constant (kel) of 0.11 ± 0.05 h(-1) (mean ± standard deviation) (half-life of 9.8 h). Inhibitory sigmoid maximal effect (Emax) modeling revealed that the highest Emax was 3.15 ± 1.84 log10 CFU/ml on day 3, and the exposure mediating 50% of Emax (EC50) was a 0- to 24-h area under the concentration time curve (AUC0-24)-to-MIC ratio of 41.99 ± 31.78 (r(2) = 0.99). The EC80 was an AUC0-24/MIC ratio of 102.11. However, no moxifloxacin concentration killed the bacteria to burdens below the starting inoculum. There was regrowth beyond day 3 in all doses, with replacement by a resistant subpopulation that had an MIC of >32 mg/liter by the end of the experiment. A quadratic function best described the relationship between the AUC0-24/MIC ratio and the moxifloxacin-resistant subpopulation. Monte Carlo simulations of 10,000 patients revealed that the 400- to 800-mg/day doses would achieve or exceed the EC80 in ≤12.5% of patients. The moxifloxacin susceptibility breakpoint was 0.25 mg/liter, which means that almost all M. abscessus clinical strains are moxifloxacin resistant by these criteria. While moxifloxacin's efficacy against M. abscessus was poor, formal combination therapy studies with moxifloxacin are still recommended. PMID:27067317

  12. Novel hollow fiber compressor for high power, multi-mJ ultrafast lasers

    International Nuclear Information System (INIS)

    Complete text of publication follows. The current trends in ultrafast laser development include, besides the reduction of the pulse duration, also the up-scaling of the pulse energy and the increase of the repetition rate. Recently, multi-mJ, multi-kHz lasers delivering sub-30 fs pulses have become available. The compression of the output pulses of such lasers to sub-5 fs duration is a challenging task. In order to maintain good temporal contrast and beam profile, the preferred way for spectral broadening is to use noble-gas-filled hollow fibers. For launching multi-mJ pulses in the waveguide, its inner diameter has to be large in order to keep the intensity at low levels so that the ionization losses are still tolerable. For optimal in-coupling the differential pressure scheme is very favourable, which, however requires longer waveguide lengths to compensate for the reduced effective interaction length caused by the pressure gradient. Recently, a novel hollow fiber construction has been developed comprising a waveguide formed by a stretched flexible capillary tube. This special construction resolves the usual strong limitation of the length of the waveguide, provides excellent straightness, and inherently supports the differential pressure scheme. The only drawback of the flexible fiber unit to date was its susceptibility to thermal damage in case of high average power input beams. To solve this problem we present a novel composite fiber unit, which consists of a thick-walled taper followed by a long flexible fiber. This construction combines the advantages of both types: the high resistibility of the taper and the free length-scalability of a flexible fiber. In order to demonstrate the potential of the new fiber design, a 2 m long composite fiber with an inner diameter of 320 μm was placed at the output of a CPA Ti:Sa laser system comprising an oscillator, a grating-prism (grism) stretcher, two multi-pass amplifier stages and a compressor combining bulk glass

  13. Aminosilane-Functionalized Hollow Fiber Sorbents for Post-Combustion CO 2 Capture

    KAUST Repository

    Li, Fuyue Stephanie

    2013-07-03

    Increasing carbon dioxide emissions are generally believed to contribute to global warming. Developing new materials for capturing CO2 emitted from coal-fired plants can potentially mitigate the effect of these CO 2 emissions. In this study, we developed and optimized porous hollow fiber sorbents with both improved sorption capacities and rapid sorption kinetics by functionalizing aminosilane (N-(2-aminoethyl)-3- aminoisobutyldimethylmethoxysilane) to cellulose acetate hollow fibers as a "proof of concept". A lumen-side barrier layer was also developed in the aminosilane-functionalized cellulose acetate fiber sorbent to allow for facile heat exchange without significant mass transfer with the bore-side heat transfer fluid. The functionalized cellulose acetate fiber sorbents were characterized by pressure decay sorption measurements, multicomponent column chromatography, FT-IR, elemental analysis, and scanning electron microscopy. The carbon dioxide sorption capacity at 1 atm is 0.73 mmol/g by using the pressure decay apparatus. Multicomponent column chromatography measurements showed that aminosilane functionalized cellulose acetate fiber sorbent has a CO2 sorption capacity of 0.23 mmol/g at CO2 partial pressure 0.1 atm and 35 C in simulated flue gas. While this capacity is low, our proof of concept positions the technology to move forward to higher capacity with work that is underway. The presence of silicon and nitrogen elements in the elemental analysis confirmed the success of grafting along with FT-IR spectra which showed the absorbance peak (∼810 cm-1) for Si-C stretching. A cross-linked Neoprene material was used to form the lumen-side barrier layer. Preliminary data showed the required reduction in gas permeance to eliminate mixing between shell side and bore side fluid flows. Specifically the permeance was reduced from 10 000 GPUs for the neat fibers to 6.6 ± 0.1 and 3.3 ± 0.3 GPUs for the coated fibers. The selected lumen layer formation materials

  14. Pressure retarded osmosis dual-layer hollow fiber membranes developed by co-casting method and ammonium persulfate (APS) treatment

    KAUST Repository

    Fu, Fengjiang

    2014-11-01

    Delamination and low water permeability are two issues limiting the applications of dual-layer hollow fiber membranes in the pressure retarded osmosis (PRO) process. In this work, we first developed a universal co-casting method that is able to co-cast highly viscous dope solutions to form homogeneous dual-layer flat sheet membranes. By employing this method prior to the tedious dual-layer hollow fiber spinning process, both time and material consumptions are significantly saved. The addition of polyvinylpyrrolidone (PVP) is found to eliminate delamination at the sacrifice of water flux. A new post-treatment method that involves flowing ammonium persulfate (APS) solution and DI water counter-currently is potentially to remove the PVP molecules entrapped in the substrate while keeps the integrity of the interface. As the APS concentration increases, the water flux in the PRO process is increased while the salt leakage is slightly decreased. With the optimized APS concentration of 5wt%, the post-treated membrane shows a maximum power density of 5.10W/m2 at a hydraulic pressure of 15.0bar when 1M NaCl and 10mM NaCl were used as the draw and feed solutions, respectively. To the extent of our knowledge, this is the best phase inversion dual-layer hollow fiber membrane with an outer selective layer for osmotic power generation. © 2014 Elsevier B.V.

  15. Hyperbranched polyethyleneimine induced cross-linking of polyamide-imide nanofiltration hollow fiber membranes for effective removal of ciprofloxacin.

    Science.gov (United States)

    Sun, Shi Peng; Hatton, T Alan; Chung, Tai-Shung

    2011-05-01

    This study aims to develop a positively charged nanofiltration (NF) hollow fiber membrane for effective removal of ciprofloxacin from water. A novel NF membrane was fabricated by hyperbranched polyethyleneimine (PEI) induced cross-linking on a polyamide-imide hollow fiber support. The spongy-like, fully porous membrane support provides minimal transport resistance and sufficient mechanical strengths for water permeation under high pressures. It is found that the PEI modification significantly influences NF performance through the mechanisms of size exclusion, charge repulsion, and solute-membrane affinity. Specifically, after PEI induced cross-linking, the membrane pore size is significantly reduced. The membrane surface becomes more hydrophilic and positively charged. As a result of these synergic effects, the rejection of ciprofloxacin is substantially enhanced. Furthermore, experimental results show that the molecular weight of PEI has tremendous effect on NF performance of the as-modified membrane. The NF membrane modified by a high molecular weight PEI_60K exhibits the highest rejection, the lowest fouling tendency, and keeps a constant flux over the whole pH range. This study may have great potential for developing high-performance antifouling NF hollow fiber membranes for various industrial applications. PMID:21456576

  16. Hollow-fiber micro-extraction combined with HPLC for the determination of sitagliptin in urine samples

    Directory of Open Access Journals (Sweden)

    Rezaee Raheme

    2015-01-01

    Full Text Available This study successfully developed a three-phase hollow-fiber liquid phase micro extraction coupled with high performance liquid chromatography for determination of trace levels of an anti-diabetic drug, sitagliptin (STG, in urine samples. Sitagliptin was extracted from 15 mL of the basic sample solution with a pH of 8.5 into an organic extracting solvent (n-octanol impregnated in the pores of a hollow fiber and then back extracted into an acidified aqueous solution in the lumen of the hollow fiber with a pH of 3. After extraction, 20 µL of the acceptor phase was injected into HPLC. In order to obtain high extraction efficiency, the parameters affecting the HF-LPME including pH of the source and receiving phases, type of organic phase, ionic strength, stirring rate, extraction time, the volume ratio of donor phase to acceptor phase and temperature were studied and optimized. Under the optimized conditions, enrichment factors up to 88 were achieved and the relative standard deviation of the method was in the range of 3 % to 6%. The results indicated that HF-LPME method has an excellent clean-up capacity and a high preconcentration factor and can serve as a simple and sensitive method for monitoring the drug in the urine samples.

  17. Propagation dynamics of femtosecond laser pulses in a hollow fiber filled with argon: constant gas pressure versus differential gas pressure

    Science.gov (United States)

    Nurhuda, Muhammad; Suda, Akira; Midorikawa, Katsumi; Hatayama, Masatoshi; Nagasaka, Keigo

    2003-09-01

    We investigate the dynamics of femtosecond laser pulses propagating in a hollow fiber filled with argon, through a full numerical solution of the nonlinear Schrödinger equation. The simulation results show that, if the intensity is low and no ionization takes place, the spatial profile of the beam does not change very much so that its propagation model may be simplified to a one-dimensional model. If the intensity is high and ionization takes place, the spatial dynamics as well as temporal dynamics become very complicated because of self-focusing and defocusing. It is found that, for the same value of the B integral, self-focusing inside a hollow fiber can be substantially suspended by a differential gas pressure technique, where the gas pressure is set to be a minimum at the entrance and then increased with the propagation distance. Numerical simulations show that using such a technique, the energy transmitted during propagation inside hollow fiber is significantly enhanced, and the spatial phase is also improved.

  18. Self-formation of microporous polysulfone hollow fiber using a single nozzle spinneret and reduction of phase-inversion speed

    Science.gov (United States)

    Kim, Hyung Jin; Jang, Chang Sik; Kim, Byeong Hee; Seo, Young Ho

    2016-06-01

    This study proposed a simple fabrication technique for microporous hollow fibers whose inner channel was naturally formed because of a slow phase inversion speed. Conventionally, microporous hollow fibers have been fabricated by extruding a polymer solution through the outer nozzle and a bore liquid through the inner nozzle of a dual nozzle spinneret. Injecting a bore liquid played a key role for the formation of a hollow structure. In this study, the self-formation of a hollow structure of microporous fiber was developed using a single nozzle spinneret without a bore liquid. A sharp tip single nozzle spinneret of 200 µm in diameter was fabricated by the wetting effect of a liquid pre-polymer of polydimethylsiloxane, and polysulfone solution was extruded through the prepared single nozzle spinneret. The temperature of the coagulant bath was controlled in order to reduce the speed of phase change, because the phase-change speed depended on the temperature of the coagulant solution. An inner channel in the microporous fiber was successfully fabricated by reducing the phase-change speed and by increasing the solidification speed. The inner diameter of the microporous hollow fiber was decreased as the temperature of the coagulant bath was increased, and eventually the inner channel was not formed at the higher bath temperature rather than 25 °C.

  19. Outer-selective pressure-retarded osmosis hollow fiber membranes from vacuum-assisted interfacial polymerization for osmotic power generation

    KAUST Repository

    Sun, Shipeng

    2013-11-19

    In this paper, we report the technical breakthroughs to synthesize outer-selective thin-film composite (TFC) hollow fiber membranes, which is in an urgent need for osmotic power generation with the pressure-retarded osmosis (PRO) process. In the first step, a defect-free thin-film composite membrane module is achieved by vacuum-assisted interfacial polymerization. The PRO performance is further enhanced by optimizing the support in terms of pore size and mechanical strength and the TFC layer with polydopamine coating and molecular engineering of the interfacial polymerization solution. The newly developed membranes can stand over 20 bar with a peak power density of 7.63 W/m2, which is equivalent to 13.72 W/m2 of its inner-selective hollow fiber counterpart with the same module size, packing density, and fiber dimensions. The study may provide insightful guidelines for optimizing the interfacial polymerization procedures and scaling up of the outer-selective TFC hollow fiber membrane modules for PRO power generation. © 2013 American Chemical Society.

  20. [Immobilization and characterization of carbonic anhydrase on the surface of hollow fiber membrane of polymethyl pentene].

    Science.gov (United States)

    Wang, Qinmei; Zhang, Dihua; Zhang, Jingxia

    2009-07-01

    We immobilized carbonic anhydrase (CA) onto the surface of membrane oxygenator of polymethyl pentene (PMP) to enhance the removal of carbon dioxide in blood by two steps. We first introduced hydroxyl groups onto PMP surface by water plasma treatment, and then coupled CA onto PMP surface by using cyanate bromide (CNBr) as a crosslinker. After plasma treatment, the contact angle with water and chemical composition of PMP surface were characterized by analysis system of surface contact angle and XPS. Using p-nitrophenyl acetate (p-NPA) as a substrate, the activity, concentration, storage stability and re-usability of immobilized CA on PMP hollow fibers were studied by ultraviolet spectrophotometer. The preliminary data showed that hydroxyl groups could be introduced on the surface of PMP by water plasma treatment, and CA with catalysis activity could be successfully introduced onto PMP surface in high immobilization efficiency. The activity of covalently immobilized CA increased with the increase of concentration of CNBr, and the maximum was 73% of the theoretical activity of CA spread on PMP surface in monolayer in studied range. Covalently immobilized CA showed higher reusability compared to physically adsorbed CA, and higher storage stability compared to free CA in solution at 37 degrees C. The method would be used potentially in the membrane oxygenator to improve the capacity of removal of carbon dioxide in blood in the future. PMID:19835148

  1. Understanding the risk of scaling and fouling in hollow fiber forward osmosis membrane application

    KAUST Repository

    Majeed, Tahir

    2016-06-23

    Fouling studies of forward osmosis (FO) were mostly conducted based on fouling evaluation principals applied to pressure membrane processes such as reverse osmosis (RO)/nanofiltration (NF)/microfiltration (MF)/ultrafiltration (UF). For RO/NF/MF/UF processes, the single flux driving force (hydraulic pressure) remains constant, thus the fouling effect is easily evaluated by comparing flux data with the baseline. Whilst, the scenario of fouling effects for FO process is entirely different from RO/NF/MF/UF processes. Continuously changing driving force (osmotic pressure difference), the changes in concentration polarization associated with the varying draw solution/feed solution concentration and the fouling layer effects collectively influence the FO flux. Thus, usual comparison of the FO flux outcome with the baseline results can not exactly indicate the real affect of membrane fouling, rather presents a misleading cumulative effect. This study compares the existing FO fouling technique with an alternate fouling evaluation approach using two FO set-ups. Scaling and fouling risk for hollow fiber FO was separately investigated using synthetic water samples and model organic foulants as alginate, humic acid and bovine serum albumin. Results indicated that FO flux declines up to 5% and 49% in active layer-feed solution and active layer-draw solution orientations respectively.

  2. Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

    Science.gov (United States)

    Mercado-Pagán, Ángel E.; Kang, Yunqing; Findlay, Michael W.; Yang, Yunzhi

    2015-01-01

    Engineering of small diameter (<6 mm) vascular grafts (SDVGs) for clinical use, remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFM) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5×10−6 cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. PMID:25686982

  3. Performance of Hollow Fiber Ultrafiltration Membranes in the Clarification of Blood Orange Juice

    Directory of Open Access Journals (Sweden)

    Carmela Conidi

    2015-12-01

    Full Text Available The clarification of blood orange juice by ultrafiltration (UF was investigated by using three hollow fiber membrane modules characterized by different membrane materials (polysulfone (PS and polyacrylonitrile (PAN and molecular weight cut-off (MWCO (50 and 100 kDa. The performance of selected membranes was investigated in terms of productivity and selectivity towards total anthocyanin content (TAC, total phenolic content (TPC, and total antioxidant activity (TAA. All selected membranes allowed a good preservation of antioxidant compounds; however, the most suitable membrane for the clarification of the juice was found to be the PS 100 kDa membrane. In optimized operating conditions this membrane exhibited steady-state fluxes of 7.12 L/m2h, higher than those measured for other investigated membranes. Rejections towards TPC and TAA were of the order of 17.5% and 15%, respectively. These values were lower than those determined for PS 50 kDa and PAN 50 kDa membranes. In addition, the PS 100 kDa membrane exhibited a lower rejection (7.3% towards TAC when compared to the PS 50 kDa membrane (9.2%.

  4. Covalent Immobilization of Lipase on Poly ( acrylonitrile-co-maleic acid) Ultrafiltration Hollow Fiber Membrane

    Institute of Scientific and Technical Information of China (English)

    YE Peng; XU Zhi-kang; WU Jian; DENG Hong-tao; SETA Patrick

    2005-01-01

    Lipase from Candida rugosa was covalently immobilized on the surface of an ultrafiltration hollow fiber membrane fabricated from poly (acrylonitrile-co-maleic acid) (PANCMA) in which the carboxyl groups were activated with 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) and dicyclohexyl carbodiimide (DCC)/N-hydroxyl succinimide(NHS), respectively. The properties of the immobilized lipase were assayed and compared with those of the free enzyme. The maximum activities were observed in a relatively broader pH value range at high temperatures for the immobilized lipase compared to the free one. It was also found that the thermal and pH stabilities of lipase were improved upon immobilization and at 50 ℃ the thermal inactivation rate constant values are 2.1×10-2 for the free lipase, 3.2×10-3 for the immobilized lipase on the EDC-activated PANCMA membrane and 3.5×10-3 for the immobilized lipase on the DCC/NHS-activated PANCMA membrane, respectively.

  5. Operation Characteristics of Treating Surface Water with Polyvinylchloride Hollow Fiber Ultrafiltration Membrane

    Institute of Scientific and Technical Information of China (English)

    GUO Xiaoyan; ZHANG Zhenjia; FANG Lin; SU Liguo

    2006-01-01

    A pilot plant study on a polyvinylchloride hollow fiber ultrafiltration membrane process was conducted for treating surface water.The membrane system was operated in the dead-end filtration mode under different constant permeate fluxes.The results show that the optimized operation ( transmembrane pressure≤0.1 Mpa,filtration time≤30 min) with a hydraulic cleaning (30 s) and a chemical cleaning (30 min,the chemical cleaning was performed after 16 cycles of filtration ) en ures a quite steady flux (1 100 L/(m2·h · Mpa)) and good permeate quality (turbidity <0.1NTU ).A full-scale plant can be suggested to operate with a mixed strategy of constant permeate flux mode (transmembrane pressure ≤0.1 Mpa) and constant transmembrane pressure mode.When the temperature of raw water becomes below 5 ℃,a constant transmembrane pressure mode should be used; otherwise a constant permeate flux mode (transmembrane pressure ≤ 0.1 Mpa) can be operated.In this way,irreversible fouling of ultrafiltration membrane can be minimized to keep a stable flux and make the life of membrane longer.

  6. Enhanced forward osmosis from chemically modified polybenzimidazole (PBI) nanofiltration hollow fiber membranes with a thin wall

    KAUST Repository

    Wang, Kai Yu

    2009-04-01

    To develop high-flux and high-rejection forward osmosis (FO) membranes for water reuses and seawater desalination, we have fabricated polybenzimidazole (PBI) nanofiltration (NF) hollow fiber membranes with a thin wall and a desired pore size via non-solvent induced phase inversion and chemically cross-linking modification. The cross-linking by p-xylylene dichloride can finely tune the mean pore size and enhance the salt selectivity. High water permeation flux and improved salt selectivity for water reuses were achieved by using the 2-h modified PBI NF membrane which has a narrow pore size distribution. Cross-linking at a longer time produces even a lower salt permeation flux potentially suitable for desalination but at the expense of permeation flux due to tightened pore sizes. It is found that draw solution concentration and membrane orientations are main factors determining the water permeation flux. In addition, effects of membrane morphology and operation conditions on water and salt transport through membrane have been investigated. © 2008 Elsevier Ltd. All rights reserved.

  7. Solvent recovery from soybean oil/n-butane mixtures using a hollow fiber ultrafiltration membrane

    Directory of Open Access Journals (Sweden)

    M. V. Tres

    2014-03-01

    Full Text Available The aim of this work was the study on the separation of soybean oil/n-butane mixtures using a commercial hollow fiber ultrafiltration membrane (50 kDa. Oil/n-butane mixtures with mass ratios of 1:1 and 1:3 (wt, with the feed pressures of 5, 7 and 10 bar and transmembrane pressure of 1 bar were studied. Rejections of oil between 21 to 97.2%, oil fluxes between 0.04 and 0.98 kg/m² h and n-butane fluxes between 4 and 46 kg/m² h were observed, strongly influenced by the feed concentration. The increase in oil/n-butane mass ratio caused an increase in oil rejection and a decrease in the permeate flux of oil for most assays. The increase in the operating pressure caused an increase in oil flux and a consequent decrease in oil rejection. No degradation was observed in the membrane module during the operation with this non-aqueous feed stream, as confirmed by integrity tests.

  8. Synthesis and characterization of polycaprolactone urethane hollow fiber membranes as small diameter vascular grafts.

    Science.gov (United States)

    Mercado-Pagán, Ángel E; Stahl, Alexander M; Ramseier, Michelle L; Behn, Anthony W; Yang, Yunzhi

    2016-07-01

    The design of bioresorbable synthetic small diameter (hollow fiber membranes (HFMs) as SDVG candidates, and characterized their mechanical properties, degradability, hemocompatibility, and endothelial development. The HFMs had smooth surfaces and porous internal structures. Their tensile stiffness ranged from 0.09 to 0.11N/mm and their maximum tensile force from 0.86 to 1.03N, with minimum failure strains of approximately 130%. Permeability varied from 1 to 14×10(-6)cm/s, burst pressures from 1158 to 1468mmHg, and compliance from 0.52 to 1.48%/100mmHg. The suture retention forces ranged from 0.55 to 0.81N. HFMs had slow degradation profiles, with 15 to 30% degradation after 8weeks. Human endothelial cells proliferated well on the HFMs, creating stable cell layer coverage. Hemocompatibility studies demonstrated low hemolysis (<2%), platelet activation, and protein adsorption. There were no significant differences in the hemocompatibility of HFMs in the absence and presence of endothelial layers. These encouraging results suggest great promise of our newly developed materials and biodegradable elastomeric HFMs as SDVG candidates. PMID:27127029

  9. Preparation and Preliminary Dialysis Performance Research of Polyvinylidene Fluoride Hollow Fiber Membranes

    Directory of Open Access Journals (Sweden)

    Qinglei Zhang

    2015-03-01

    Full Text Available In this study, the separation properties of Polyvinylidene fluoride (PVDF hollow fiber hemodialysis membranes were improved by optimizing membrane morphology and structure. The results showed that the PVDF membrane had better mechanical and separation properties than Fresenius Polysulfone High-Flux (F60S membrane. The PVDF membrane tensile stress at break, tensile elongation and bursting pressure were 11.3 MPa, 395% and 0.625 MPa, respectively. Ultrafiltration (UF flux of pure water reached 108.2 L∙h−1∙m−2 and rejection of Albumin from bovine serum was 82.3%. The PVDF dialyzers were prepared by centrifugal casting. The influences of membrane area and simulate fluid flow rate on dialysis performance were investigated. The results showed that the clearance rate of urea and Lysozyme (LZM were improved with increasing membrane area and fluid flow rate while the rejection of albumin from bovine serum (BSA had little influence. The high-flux PVDF dialyzer UF coefficient reached 62.6 mL/h/mmHg. The PVDF dialyzer with membrane area 0.69 m2 has the highest clearance rate to LZM and urea. The clearance rate of LZM was 66.8% and urea was 87.7%.

  10. Development and characterization of microfiltration hollow-fiber modules for sterilization of fermentation media

    Directory of Open Access Journals (Sweden)

    Faria L.F.F.

    2002-01-01

    Full Text Available Sterilization of fermentation medium involving heat may result in undesirable chemical reactions that alter nutrient concentration and yield products, which interfere in the fermentation performance. Sterilization of heat-sensitive compounds usually involves separate sterilizations of carbon source and nutrient solution. Membrane separation processes are an alternative to thermal processes, as they have many advantages such as the possibility of continuous and modular operation and the use of moderate temperatures. In this context, the objective of this work was the preparation of hollow-fiber membranes and the design of modules suitable for continuous sterilization of fermentation medium. The membrane with the best performance had a maximum pore diameter of 0.2 mu m and a permeability of 42.9 L/m².bar.h for a glucose/peptone/yeast extract medium. A module with 0.26 m² of permeation area was built with these membranes. This module was able to provide a permeate flow rate of 2.2 L/h using a pressure difference of 0.2 bar. The collected permeate was completely sterile, thus confirming the efficiency of this process.

  11. Application of hollow fiber supported liquid membrane for the separation of americium from the analytical waste

    International Nuclear Information System (INIS)

    Americium from analytical solid waste containing U and metallic impurities was separated using hollow fiber supported liquid membrane (HFSLM) technique impregnated with DHOA-TODGA from nitric acid medium. An aliquot of 5 g of the solid waste containing Am (19.95 mg) as minor actinide and of U (2,588 mg), Fe (1,360 mg), Ca (1,810 mg) and Na (3,130 mg) as major impurities was processed. The feed solution obtained after the dissolution of the residue in ∼4 M HNO3 was passed through HFSLM module. In the first stage using 1 M DHOA-dodecane was used for the separation of Am from other impurities. Though, majority of the elements were separated in this cycle, Ca was co extracted along with the americium. CMPO extraction chromatographic technique was used for further separation of americium from Ca. Significant decontamination factors were achieved in this three step separation process with respect to U, Fe, Na and Ca with ∼77 % recovery of americium. (author)

  12. Fabrication of micro-hollow fiber by electrospinning process in near-critical carbon dioxide

    International Nuclear Information System (INIS)

    Electrospinning is a simple technique that has gained much attention because of its capability and feasibility in the fabrication of large quantities of fibers from polymer with diameters ranging in nano-microscale. These fibers provided high surface area to volume ratios, and it was of considerable interest for many applications, such as nanoparticle carriers in controlled release, scaffolds in tissue engineering, wound dressings, military wear with chemical and biological toxin-resistance, nanofibrous membranes or filters, and electronic sensors. Recently there has been a great deal of progress in the potential applications of hollow fibers in microfluids, photonics, and energy storage. In this work, electrospinning was conducted under high-pressure carbon dioxide (CO2) to reduce the viscosity of polymer solution. The experiments were conducted at 313 K and ∼8.0 MPa. Polymer solution containing 5 wt% polymers which prepared in dichloromethane (DCM) with polyvinylpyrrolidone (PVP) to poly-L-lactic acid (PLLA) ratio 80:20 was used as a feed solution. The applied voltage was 15 kV and the distance of nozzle and collector was 8 cm. The morphology and structure of the fibers produced were observed using scanning electron microscopy (SEM). Under pressurized CO2, PVP electrospun was produced without bead formation with diameter ranges of 608.50 - 7943.19 nm. These behaviors hold the potential to considerably improve devolatilization electrospinning processes

  13. Surface monofunctionalized polymethyl pentene hollow fiber membranes by plasma treatment and hemocompatibility modification for membrane oxygenators

    Science.gov (United States)

    Huang, Xin; Wang, Weiping; Zheng, Zhi; Fan, Wenling; Mao, Chun; Shi, Jialiang; Li, Lei

    2016-01-01

    The hemocompatibility of polymethyl pentene (PMP) hollow fiber membranes (HFMs) was improved through surface modification for membrane oxygenator applications. The modification was performed stepwise with the following: (1) oxygen plasma treatment, (2) functionalization of monosort hydroxyl groups through NaBH4 reduction, and (3) grafting 2-methacryloyloxyethyl phosphorylcholine (MPC) or heparin. SEM, ATR-FTIR, and XPS analyses were conducted to confirm successful grafting during the modification. The hemocompatibility of PMP HFMs was analyzed and compared through protein adsorption, platelet adhesion, and coagulation tests. Pure CO2 and O2 permeation rates, as well as in vitro gas exchange rates, were determined to evaluate the mass transfer properties of PMP HFMs. SEM results showed that different nanofibril topographies were introduced on the HFM surface. ATR-FTIR and XPS spectra indicated the presence of functionalization of monosort hydroxyl group and the grafting of MPC and heparin. Hemocompatibility evaluation results showed that the modified PMP HFMs presented optimal hemocompatibility compared with pristine HFMs. Gas permeation results revealed that gas permeation flux increased in the modified HFMs because of dense surface etching during the plasma treatment. The results of in vitro gas exchange rates showed that all modified PMP HFMs presented decreased gas exchange rates because of potential surface fluid wetting. The proposed strategy exhibits a potential for fabricating membrane oxygenators for biomedical applications to prevent coagulation formation and alter plasma-induced surface topology and composition.

  14. A hollow fiber membrane based system for the rapid synthesis of labelled formaldehyde

    International Nuclear Information System (INIS)

    An improved enzymatic method has been developed for the synthesis of labeled formaldehyde. C-11 labeled formaldehyde is a key intermediate in the synthesis of several radiopharmaceuticals e.g. 11C thymidine. The authors' approach was based on the use of enzymes attached to bioactive microporous membranes. Alcohol oxidase and catalase were covalently attached to a hollow fiber membrane (HFM) support. Alcohol oxidase catalyzes the reaction of methanol and oxygen to formaldehyde and hydrogen peroxide. Catalase breaks down hydrogen peroxide to water and oxygen thus serving as an oxygen regenerator for the system. The enzyme linked HFM was able to generate 0.5 umole of formaldehyde/min. Enzyme immobilization to a HFM obviates the need for separation of the enzyme from the reaction mixture, while the ability to supply reactants to the immobilized enzyme by convective flow of the solution into and through the microporous support membrane eliminates diffusional resistances that would otherwise slow the reaction kinetics. This system can reduce the total synthesis and purification time, an important factor considering the 20.4 min half-life of Carbon-11

  15. Human proximal tubule epithelial cells cultured on hollow fibers: living membranes that actively transport organic cations.

    Science.gov (United States)

    Jansen, J; De Napoli, I E; Fedecostante, M; Schophuizen, C M S; Chevtchik, N V; Wilmer, M J; van Asbeck, A H; Croes, H J; Pertijs, J C; Wetzels, J F M; Hilbrands, L B; van den Heuvel, L P; Hoenderop, J G; Stamatialis, D; Masereeuw, R

    2015-01-01

    The bioartificial kidney (BAK) aims at improving dialysis by developing 'living membranes' for cells-aided removal of uremic metabolites. Here, unique human conditionally immortalized proximal tubule epithelial cell (ciPTEC) monolayers were cultured on biofunctionalized MicroPES (polyethersulfone) hollow fiber membranes (HFM) and functionally tested using microfluidics. Tight monolayer formation was demonstrated by abundant zonula occludens-1 (ZO-1) protein expression along the tight junctions of matured ciPTEC on HFM. A clear barrier function of the monolayer was confirmed by limited diffusion of FITC-inulin. The activity of the organic cation transporter 2 (OCT2) in ciPTEC was evaluated in real-time using a perfusion system by confocal microscopy using 4-(4-(dimethylamino)styryl)-N-methylpyridinium iodide (ASP(+)) as a fluorescent substrate. Initial ASP(+) uptake was inhibited by a cationic uremic metabolites mixture and by the histamine H2-receptor antagonist, cimetidine. In conclusion, a 'living membrane' of renal epithelial cells on MicroPES HFM with demonstrated active organic cation transport was successfully established as a first step in BAK engineering. PMID:26567716

  16. Separation of dissolved Kr from a water sample by means of a hollow fiber membrane

    Science.gov (United States)

    Ohta, T.; Mahara, Y.; Momoshima, N.; Inoue, F.; Shimada, J.; Ikawa, R.; Taniguchi, M.

    2009-09-01

    SummaryWe investigated extraction of the krypton (Kr) radioisotope 85Kr from groundwater having an ultra-low concentration with a Kr extraction system using an external inflow type hollow fiber membrane. Our aim was to develop a system able to effectively extract Kr isotopes from a large volume of groundwater (10 4 L) in field studies for measurement of 85Kr radioactivity. Before testing our Kr extraction system in the field, we determined experimentally the conditions necessary for effective extraction of Kr isotopes from groundwater. We investigated the efficiency of Kr extraction from water by extracting trace amounts of Kr in the laboratory. With our system, we were able to extract 99% of Kr and O 2 dissolved in water at water temperatures ranging from 11 to 29 °C and with a flow rate of less than 24 L/min, confirming that the separation efficiency of the system was sufficient for extraction of Kr isotopes from groundwater. We then used our method to extract 85Kr from groundwater at sites at Kyoto University in Osaka and on the Kumamoto Plain in central Kyushu, Japan. We showed that this technique for extracting 85Kr from the groundwater can be an effective tool for investigating the residence time of young groundwater.

  17. Designing the inner surface corrugations of hollow fibers to enhance CO2 absorption efficiency.

    Science.gov (United States)

    Fashandi, Hossein; Zarrebini, Mohammad; Ghodsi, Ali; Saghafi, Reza

    2016-08-15

    For the first time, a low cost strategy is introduced to enhance the efficiency of CO2 absorption using gas-liquid membrane contactors. This is implemented by designing the corrugations in the inner layer of poly(vinyl chloride) hollow fibers (PVC HFs) through changing the bore fluid composition. In fact, the number of corrugations in the HF inner layer is engineered via changing the phase separation time within the inner layer. Such that expedited phase separation leads to highly corrugated inner layer. In contrast, decelerated phase separation is responsible for reduced number of inner layer corrugations. Phase separation causes the initial polymer solution with low viscoelastic moduli to be transferred into polymer-rich domains with high viscoelastic moduli. These domains resist against stretching-induced radial forces toward the center of HF; therefore, the inner layer of HF buckles. Delayed phase separation defers formation of polymer-rich domains and hence, HF with less corrugated inner surface is expected. The phase separation within the HF inner layer is controlled through changing the rate of solvent/nonsolvent exchange. This is conducted by variation the solvent content in the bore fluid; as higher as solvent content, as slower as solvent/nonsolvent exchange. PMID:27179177

  18. NMR and MRI of continuously dissolved hyperpolarized {sup 129}Xe by means of hollow fibers

    Energy Technology Data Exchange (ETDEWEB)

    Amor, Nadia; Kueppers, Markus; Bluemich, Bernhard [ITMC of RWTH Aachen University (Germany); Hamilton, Kathrin; Schmitz-Rode, Thomas; Steinseifer, Ulrich [HIA of RWTH Aachen University (Germany); Appelt, Stephan [Research Center Juelich (Germany)

    2011-07-01

    Various methods of hyperpolarizing (HP) spin systems have been developed during the last years to increase the intrinsically low sensitivity of NMR by several orders of magnitude. Among them is the hyperpolarization of {sup 129}Xe via Spin Exchange Optical Pumping (SEOP). NMR of HP {sup 129}Xe is of great interest because of its good solubility and its very sensitive chemical shift. The main obstacle for many applications is the efficient and continuous dissolution into carrier agents without formation of foams or bubbles. It has been overcome by the so-called ''xenonizer'' setups. They mainly consist of commercially available hollow fiber membranes typically used in clinical oxygenators. A purpose-built xenonizer setup has been developed and analyzed in detail by NMR spectroscopy and MRI for varying fiber materials as well as for different fluids, including bio-relevant fluids such as blood, plasma, and erythrocytes. As a result, the xenonizer technology could be further understood and improved, and new applications of HP {sup 129}Xe for medical NMR were explored.

  19. Hollow-fiber membrane bioreactor for the treatment of high-strength landfill leachate

    KAUST Repository

    Rizkallah, Marwan

    2013-07-15

    Performance assessment of membrane bioreactor (MBR) technology for the treatability of high-strength landfill leachate is relatively limited or lacking. This study examines the feasibility of treating high-strength landfill leachate using a hollow-fiber MBR. For this purpose, a laboratory-scale MBR was constructed and operated to treat leachate with a chemical oxygen demand (COD) of 9000-11,000 mg/l, a 5-day biochemical oxygen demand (BOD5) of 4000-6,000 mg/l, volatile suspended solids (VSS) of 300-500 mg/l, total nitrogen (TN) of 2000-6000 mg/l, and an ammonia-nitrogen (NH3-N) of 1800-4000 mg/l. VSS was used with the BOD and COD data to simulate the biological activity in the activated sludge. Removal efficiencies > 95-99% for BOD5, VSS, TN and NH3-N were attained. The coupled experimental and simulation results contribute in filling a gap in managing high-strength landfill leachate and providing guidelines for corresponding MBR application. © The Author(s) 2013.

  20. Polyethyleneimine-Functionalized Polyamide Imide (Torlon) Hollow-Fiber Sorbents for Post-Combustion CO 2 Capture

    KAUST Repository

    Li, Fuyue Stephanie

    2013-05-24

    Carbon dioxide emitted from existing coal-fired power plants is a major environmental concern due to possible links to global climate change. In this study, we expand upon previous work focused on aminosilane-functionalized polymeric hollow-fiber sorbents by introducing a new class of polyethyleneimine (PEI)-functionalized polymeric hollow-fiber sorbents for post-combustion carbon dioxide capture. Different molecular weight PEIs (Mn≈600, 1800, 10 000, and 60 000) were studied as functional groups on polyamide imide (PAI, Torlon) hollow fibers. This imide ring-opening modification introduces two amide functional groups and was confirmed by FTIR attenuated total reflectance spectroscopy. The carbon dioxide equilibrium sorption capacities of PEI-functionalized Torlon materials were characterized by using both pressure decay and gravimetric sorption methods. For equivalent PEI concentrations, PAI functionalized with lower molecular weight PEI exhibited higher carbon dioxide capacities. The effect of water in the ring-opening reaction was also studied. Up to a critical value, water in the reaction mixture enhanced the degree of functionalization of PEI to Torlon and resulted in higher carbon dioxide uptake within the functionalized material. Above the critical value, roughly 15 % w/w water, the fiber morphology was lost and the fiber was soluble in the solvent. PEI-functionalized (Mn≈600) PAI under optimal reaction conditions was observed to have the highest CO2 uptake: 4.9 g CO2 per 100 g of polymer (1.1 mmol g-1) at 0.1 bar and 35°C with dry 10 % CO2/90 % N2 feed for thermogravimetric analysis. By using water-saturated feeds (10 % CO2/90 % N2 dry basis), CO2 sorption was observed to increase to 6.0 g CO2 per 100 g of sorbent (1.4 mmol g-1). This material also demonstrated stability in cyclic adsorption-desorption operations, even under wet conditions at which some highly effective sorbents tend to lose performance. Thus, PEI-functionalized PAI fibers can be

  1. In situ generated dense shell-engaged Ostwald ripening: A facile controlled-preparation for BaFe12O19 hierarchical hollow fiber arrays

    International Nuclear Information System (INIS)

    This paper describes a simple and convenient approach to fabricate BaFe12O19 hierarchical hollow fibers or hollow fiber arrays by heat-treating electrospun solid fibers or fiber arrays using a deliberately devised two-step heat-treatment process, in which the dense shells generated in situ during the short-time pre-treatment procedure direct Ostwald ripening of flake-shaped BaFe12O19 nanocrystals in the elevated temperature heat-treatment procedure. The heat-treatment temperature has a strong effect on the structure and magnetic properties of the BaFe12O19 hierarchical hollow fibers and the resulting BaFe12O19 hierarchical hollow fiber arrays show a slight magnetic anisotropy as well as high coercivity. The in situ generated dense shell-engaged directing Ostwald ripening approach reported here can be readily extended to fabricate other metal oxides hollow fibers, and the resulting BaFe12O19 hierarchical hollow fibers or hollow fiber arrays are promised to have use in a number of applications that involve microwave absorber, magnetic separation, and so forth. - Graphical abstract: This paper described a simple and convenient approach that allows for the facile fabrication of BaFe12O19 hierarchical nanotubes or nanotube arrays by a deliberately devised two-step heat-treatment process, in which the dense shells generated in situ during the short-time pre-treatment procedure direct Ostwald ripening of flake-shaped BaFe12O19 nanocrystals in the elevated temperature heat-treatment procedure.

  2. Chitosan-tethered poly(acrylonitrile-co-maleic acid) hollow fiber membrane for lipase immobilization.

    Science.gov (United States)

    Ye, Peng; Xu, Zhi-Kang; Che, Ai-Fu; Wu, Jian; Seta, Patrick

    2005-11-01

    A protocol was used to prepare a dual-layer biomimetic membrane as support for enzyme immobilization by tethering chitosan on the surface of poly(acrylonitrile-co-maleic acid) (PANCMA) ultrafiltration hollow fiber membrane in the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxylsuccin-imide (NHS). The chemical change of the chitosan-modified PANCMA membrane surface was confirmed with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Lipase from Candida rugosa was immobilized on this dual-layer biomimetic membrane using glutaraldehyde (GA), and on the nascent PANCMA membrane using EDC/NHS as coupling agent. The properties of the immobilized enzymes were assayed and compared with those of the free one. It was found that both the activity retention of the immobilized lipase and the amount of bound protein on the dual-layer biomimetic membrane (44.5% and 66.5 mg/m2) were higher than those on the nascent PANCMA membrane (33.9% and 53.7 mg/m2). The kinetic parameters of the free and immobilized lipases, Km and Vmax, were also assayed. The Km values were similar for the immobilized lipases, while the Vmax value of the immobilized lipase on the dual-layer biomimetic membrane was higher than that on the nascent PANCMA membrane. Results indicated that the pH and thermal stabilities of lipase increased upon immobilization. The residual activity of the immobilized lipase after 10 uses was 53% on the dual-layer biomimetic membrane and 62% on the nascent PANCMA membrane. PMID:15919112

  3. Minimizing specific energy consumption of oxygen enrichment in polymeric hollow fiber membrane modules

    International Nuclear Information System (INIS)

    Highlights: ► A membrane model was used to optimize the energy efficiency of oxygen enrichment. ► Membrane air separation can compete with other more established technologies. ► Pressure ratio, stage cut and geometry parameters affect the energy efficiency. ► The vacuum mode is the most efficient single-stage system configuration. -- Abstract: The energy efficiency of the separation of air into an oxygen-enriched permeate and an oxygen-depleted residue stream in a polymeric hollow fiber membrane module is studied. On the basis of the modeled performance of the module, three different counter-current lumen-feed flow system configurations are compared and analyzed. The vacuum permeate configuration, where a vacuum is maintained on the permeate side of the membrane, is the most efficient single-stage process. A two-stage configuration, where the permeate of the first module is further enriched in a second stage, is also considered. By optimizing both stages the specific energy consumption can, in some cases, be further reduced. The optimization of the module geometry is not as important as the optimization of the feed parameters – the pressure ratio and stage cut. The results of polymeric membrane air separation are compared to cryogenic distillation, pressure-swing adsorption, and ion transfer membranes. Present-day polymeric membrane modules can compete with traditional techniques in specific energy consumption when the required oxygen molar fraction is low. A single-stage polymeric membrane module with a selectivity of 100 would be more efficient than other techniques up to an oxygen purity of approximately 92%.

  4. Full-Scale Hollow Fiber Spacesuit Water Membrane Evaporator Prototype Development and Testing for Advanced Spacesuits

    Science.gov (United States)

    Bue, Grant; Trevino, Luis; Tsioulos, Gus; Mitchell, Keith; Dillon, Paul; Weaver, Gregg

    2009-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform the thermal control function for advanced spacesuits to take advantage of recent advances in micropore membrane technology in providing a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. Principles of a sheet membrane SWME design were demonstrated using a prototypic test article that was tested in a vacuum chamber at JSC in July 1999. The Membrana Celgard X50-215 microporous hollow fiber (HoFi) membrane was selected after recent contamination tests as the superior candidate among commercial alternatives for HoFi SWME prototype development. Although a number of design variants were considered, one that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape, was deemed best for further development. An analysis of test data showed that eight layer stacks of the HoFi sheets that had good exposure on each side of the stack would evaporate water with high efficiency. A design that has 15,000 tubes, with 18 cm of exposed tubes between headers has been built and tested that meets the size, weight, and performance requirements of the SWME. This full-scale prototype consists of 30 stacks, each of which are formed into a chevron shape and separated by spacers and organized into three sectors of ten nested stacks. Testing has been performed to show contamination resistance to the constituents expected to be found in potable water produced by the distillation processes. Other tests showed the sensitivity to surfactants.

  5. Permeation of hydrogen isotopes through hollow fiber organic membranes: application to atmospheric detritiation systems

    International Nuclear Information System (INIS)

    The objective of this work is to design a glovebox atmosphere detritiation process using gas separation membranes. Such a system opens new insights to reduce the size of detritiation facilities and/or to remove traces of tritium, which can be present in the gloveboxes atmosphere, without water production. Three commercial hollow fiber membrane modules have been selected. They are made of various polymer materials: polycarbonate, polyimide or poly-phenylene oxide. In order to obtain more information on their morphology and their properties, they have been characterised by SEM, DSC, IR... Owing to the constraints linked to tritium handling, the separation performances of the membranes have been mainly evaluated with nitrogen containing small amounts of hydrogen or deuterium. These performances have been determined experimentally and by the development of several mathematical models. The isotope effect and the effect of the operating conditions on the separation performances have been studied. As shown, the isotope effect is negligible in the conditions of this study. Furthermore, the variations in the recovery and the enrichment performances as functions of the flow rate and the pressure can be interpreted by the establishment of a gradient of concentration along the fiber. The separation of tritium from dry air has also been investigated in order to determine the performances of a membrane detritiation process. The tritium concentration in the mixtures was less than one ppb. This study has shown the feasibility of a membrane detritiation system and allows to size an industrial prototype thanks to the experimental devices, the acquired data and the mathematical models. (author)

  6. Testing of Commercial Hollow Fiber Membranes for Space Suit Water Membrane Evaporator

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis; Tsioulos, Gus; Hanford, Anthony

    2009-01-01

    Three commercial-off-the-shelf (COTS) hollow fiber (HoFi) membrane evaporators, modified for low pressure, were tested in a vacuum chamber at pressures below 33 pascals as potential space suit water membrane evaporator (SWME) heat rejection technologies. Water quality was controlled in a series of 25 tests, first simulating potable water reclaimed from waste water and then changing periodically to simulate the ever concentrating make-up of the circulating coolant over that is predicted over the course of 100 EVAs. Two of the systems, comprised of non-porous tubes with hydrophilic molecular channels as the water vapor transport mechanism, were severely impacted by the increasing concentrations of cations in the water. One of the systems, based on hydrophobic porous polypropylene tubes was not affected by the degrading water quality, or the presence of microbes. The polypropylene system, called SWME 1, was selected for further testing. An inverse flow configuration was also tested with SWME 1, with vacuum exposure on the inside of the tubes, provided only 20% of the performance of the standard configuration. SWME 1 was also modified to block 50% and 90% of the central tube layers, and tested to investigate performance efficiency. Performance curves were also developed in back-pressure regulation tests, and revealed important design considerations arising from the fully closed valve. SWME 1 was shown to be insensitive to air bubbles injected into the coolant loop. Development and testing of a full-scale prototype based on this technology and these test results is in progress.

  7. Hollow Fiber Flight Prototype Spacesuit Water Membrane Evaporator Design and Testing

    Science.gov (United States)

    Bue, Grant; Vogel, Matt; Makinen, Janice; Tsioulos, Gus

    2010-01-01

    The spacesuit water membrane evaporator (SWME) is being developed to perform thermal control for advanced spacesuits and to take advantage of recent advances in micropore membrane technology. This results in a robust heat-rejection device that is potentially less sensitive to contamination than is the sublimator. The Membrana Celgard X50-215 microporous hollow-fiber (HoFi) membrane was selected after recent extensive testing as the most suitable candidate among commercial alternatives for continued SWME prototype development. The current design was based on a previous design that grouped the fiber layers into stacks, which were separated by small spaces and packaged into a cylindrical shape. This was developed into a full-scale prototype consisting of 14,300 tube bundled into 30 stacks, each of which is formed into a chevron shape and separated by spacers and organized into three sectors of 10 nested stacks. The new design replaced metal components with plastic ones, and has a custom built flight like backpressure valve mounted on the side of the SWME housing to reduce backpressure when fully open. The spacers that provided separation of the chevron fiber stacks were eliminated. Vacuum chamber testing showed improved heat rejection as a function of inlet water temperature and water vapor backpressure compared with the previous design. Other tests pushed the limits of tolerance to freezing and showed suitability to reject heat in a Mars pressure environment with and without a sweep gas. Tolerance to contamination by constituents expected to be found in potable water produced by distillation processes was tested in a conventional way by allowing constituents to accumulate in the coolant as evaporation occurs. For this purpose, the SWME cartridge has endured an equivalent of 30 EVAs exposure and demonstrated minimal performance decline.

  8. Hydrogen Permeation Performance of Ni-BaZr0.1Ce0.7Y0.2O3-δ Metal-Ceramic Hollow Fiber Membrane

    Science.gov (United States)

    Yang, Chun-li; Xu, Qi-ming; Zhu, Zhi-wen; Liu, Wei

    2012-04-01

    A dense Ni-BaZr0.1Ce0.7Y0.2O3-δ (BZCY) cermet hollow fiber is fabricated by sintering NiO-BZCY hollow fiber precursors prepared by phase inversion method in 5%H2/95%Ar and its hydrogen permeation performance is investigated. The Ni-BZCY hollow fiber membrane possesses a “sandwich" structure. Finger-like structures are observed near both the inner and outer surfaces, while a dense layer is present in the center part. With 200 mL/min wet 20%H2/80%N2 on the shell side and 150 mL/min high purity Ar on the core side, the hydrogen permeation flux through the Ni-BZCY hollow fiber membrane at 900 °C is 0.53 μmol/cm2s. Owing to a high packing density, the hydrogen permeation flux per unit volume is greatly improved and membrane components composed of an assembly of hollow fibers may be applied in industrial hydrogen separation.

  9. Hydrogen Permeation Performance of Ni-BaZr0.1Ce0.7Y0.2O3-δ Metal-Ceramic Hollow Fiber Membrane

    Institute of Scientific and Technical Information of China (English)

    Chun-li Yang; Qi-ming Xu; Zhi-wen Zhu; Wei Liu

    2012-01-01

    A dense Ni-BaZr0.1Ce0.7Y0.2O3-δ (BZCY) cermet hollow fiber is fabricated by sintering NiOBZCY hollow fiber precursors prepared by phase inversion method in 5%H2/95%Ar and its hydrogen permeation performance is investigated. The Ni-BZCY hollow fiber membrane possesses a "sandwich" structure.Finger-like structures are observed near both the inner and outer surfaces,while a dense layer is present in the center part.With 200 mL/min wet 20%H2/80%N2 on the shell side and 150 mL/min high purity Ar on the core side,the hydrogen permeation flux through the Ni-BZCY hollow fiber membrane at 900 ℃ is 0.53 μmol/cm2s.Owing to a high packing density,the hydrogen permeation flux per unit volume is greatly improved and membrane components composed of an assembly of hollow fibers may be applied in industrial hydrogen separation.

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

    Science.gov (United States)

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

    2007-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Peng Jinfeng; Liu Rui [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085 (China); Liu Jingfu [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085 (China)], E-mail: jfliu@rcees.ac.cn; He Bin; Hu Xialin; Jiang Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, Beijing 100085 (China)

    2007-05-15

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

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

    International Nuclear Information System (INIS)

    A new procedure, based on hollow fiber supported liquid membrane preconcentration coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection, was developed for the determination of trace Cd in seawater samples. With 1-octanol that contained a mixture of dithizone (carrier) and oleic acid immobilized in the pores of the polypropylene hollow fiber as a liquid membrane, Cd was selectively extracted from water samples into 0.05 M HNO3 that filled the lumen of the hollow fiber as a stripping solution. The main extraction related parameters were optimized, and the effects of salinity and some coexisting interferants were also evaluated. Under the optimum extraction conditions, an enrichment factor of 387 was obtained for a 100-mL sample solution. In combination with graphite furnace atomic absorption spectrometry, a very low detection limit (0.8 ng L-1) and a relative standard deviation (2.5% at 50 ng L-1 level) were achieved. Five seawater samples were analyzed by the proposed method without dilution, with detected Cd concentration in the range of 56.4-264.8 ng L-1 and the relative spiked recoveries over 89%. For comparison, these samples were also analyzed by the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method after a 10-fold dilution for matrix effect elimination. Statistical analysis with a one-way ANOVA shows no significant differences (at 0.05 level) between the results obtained by the proposed and ICP-MS methods. Additionally, analysis of certified reference materials (GBW (E) 080040) shows good agreement with the certified value. These results indicate that this present method is very sensitive and reliable, and can effectively eliminate complex matrix interferences in seawater samples

  13. Separation of 90Y from 90Sr using hollow fiber supported liquid membrane containing PC-88A as the carrier

    International Nuclear Information System (INIS)

    2-Ethylhexylphosphonic acid -2- ethyl hexylmonoester (PC-88A) has been used as the extractant for Y3+ and Eu3+ (used as a surrogate) from pH solutions where Sr2+ remained inextractable. The relative extraction efficiency of PC-88A towards Y3+ and Sr2+ was investigated from dilute HNO3 media using solvent extraction, as well as hollow fiber supported liquid membrane (HFSLM) methods. A separation method for 90Y from 90Sr + 90Y mixture was developed using HFSLM method and discussed in the present paper. (author)

  14. Generation of 1.5 cycle 0.3 TW laser pulses using a hollow-fiber pulse compressor.

    Science.gov (United States)

    Park, Juyun; Lee, Jae-Hwan; Nam, Chang Hee

    2009-08-01

    Pulse compression in a differentially pumped neon-filled hollow fiber was used to generate high-power few-cycle laser pulses. The pulse compression process was optimized by adjusting gas pressure and laser chirp to produce the shortest laser pulses. Precise dispersion control enabled the generation of laser pulses with duration of 3.7 fs and energy of 1.2 mJ. This corresponds to an output of 1.5 cycle, 0.3 TW pulses at a 1 kHz repetition rate using positively chirped 33 fs laser pulses. PMID:19649091

  15. Gas-liquid mass transfer in a cross-flow hollow fiber module: Analytical model and experimental validation

    OpenAIRE

    Dindore, V. Y.; Versteeg, G. F.

    2005-01-01

    The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations of both phases in the direction of flow as well as in the direction perpendicular to flow. In addition, changes in the volumetric flow rate of compressible fluid can also occur over the volume of m...

  16. Comparative non-dispersive solvent extraction of uranium and thorium using a hollow fiber contactor containing TBP/DHOA

    International Nuclear Information System (INIS)

    Non-dispersive solvent extraction of Uranium and Thorium was carried out from nitric acid medium using hollow fiber contactor containing TBP and DHOA as the carrier extractants. The effect of flow rate was studied while carrying out the extraction studies in counter current mode using 10 g/L solutions of the metal ions in 3 M HNO3 and 50 mL/minute was found to be most suitable for better separation efficiency. Stripping studies were also carried out using deionized water as the strippant for both the metal ions. (author)

  17. A mathematical model for recovery of uranium from acidic nuclear waste using DLM in hollow fiber contractor

    International Nuclear Information System (INIS)

    A mathematical model has been developed to predict the transport of uranium through a Dispersion liquid Membrane in Hollow fiber contactor and validated with experiments. Acidic waste of uranium (U) processing plant has been used as feed with the objective of polishing of streams and recycle/safe disposal of effluent Tri-n-butyl phosphate (TBP) dissolved in dodecane was used as carrier agent and Sodium bi carbonate was used as strippant. The model predicts the rate of transport of U from feed phase to the strip phase through film diffusion and interfacial equilibrium distribution

  18. CB.Hep-1 hybridoma growth and antibody production using protein-free medium in a hollow fiber bioreactor

    OpenAIRE

    Valdés, R.; Ibarra, N.; González, M.; Alvarez, T.; GarcÍa, J.; Llambias, R.; Pérez, C. A.; Quintero, O.; Fischer, R

    2001-01-01

    The protein-free medium TurboDoma HP.1 (THP.1) was used to produce the CB.Hep-1 monoclonal antibody (mAb) in a CP-1000 hollow fiber bioreactor (HFB). This mAb is used for the immunopurification of recombinant hepatitis B surface antigen (rHBsAg), which is included in a vaccine preparation against the Hepatitis B Virus. By using the experimental conditions tested in this work we were able to generate more than 433 mg of IgG in 43 days. The maximum antibody concentration obtained was about 2.4 ...

  19. Sweeping Gas Membrane Desalination Using Commercial Hydrophobic Hollow Fiber Membranes; TOPICAL

    International Nuclear Information System (INIS)

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

  20. Daylight photocatalysis performance of biomorphic CeO2 hollow fibers prepared with lens cleaning paper as biotemplate

    International Nuclear Information System (INIS)

    Highlights: ► A novel, simple and eco-friendly approach for hierarchical, biomorphic CeO2 hollow fibers with mesoporous tube walls is presented by using paper as template. ► The biomorphic CeO2 fibers was composed of nanosheets with bimodal pore-size mesoporous distribution and exhibited high light-harvesting under sunlight irradiation. ► The CeO2 microfibers biomimicking the natural plant structures have promising application for photodegradation of organic pollutants in water. -- Abstract: Hierarchical, biomorphic CeO2 hollow fibers with mesoporous tube walls have been fabricated using lens cleaning paper as biotemplates. After sintered at 550 °C in air, the cellulosic fibers of paper were converted into micro-tubes composing of CeO2 crystallites with grain size about 8 nm. The photocatalytic activity of the CeO2 fibers was evaluated by photodegradation efficiency of methylene blue in aqueous solution under daylight irradiation. The characterized results show that the CeO2 fibers faithfully replicated micro-fibrous structure derived from original template and possessed dramatic enhanced photocatalytic activity compared with bulk CeO2. This simple biotemplate method provides a cost-effective and eco-friendly route to obtain high performance photocatalysts.

  1. PREPARATION OF ASYMMETRIC POLYETHERKETONE FLAT AND HOLLOW FIBER MEMBRANES FOR GAS SEPARATION USING ACETIC ACID BASED COAGULANTS

    Institute of Scientific and Technical Information of China (English)

    Ji-ping Yang; Philip J. Brown

    2008-01-01

    Membranes for gas separation have developed significantly in the last twenty years, however, there is still a need for high temperature and chemically resistant membranes that exhibit good selectivity and gas permeability. Our study examines the fundamental properties of polyetherketone (PEK, a thermally stable and chemically resistant polymer)membranes prepared using concentrated sulphuric acid (98% H2SO4) as the solvent. Non-solvents used in the work included acetic acid, ethanol, methanol, glycerol, and water. The concentration of the polymer solutions was chosen to be 20%. The membrane structures were examined using SEM, and the gas separation properties were measured using a lab-scale test rig.The results show that formation and control of membrane structures are complicated, and many preparation parameters affect membrane morphology and performance. Using appropriate conditions skinned sponge-like structured hollow fiber membranes could be made from PEK by using acetic acid as the internal coagulant. PEK hollow fibers spun from 20%PEK/H2SO4 solutions with 50% aqueous acetic acid as internal coagulant had selectivity for hydrogen/methane of around 40, implying a solution diffusion separation mechanism for gas separation without the need for fiber coating or after post-treatments.

  2. Hollow fiber liquid-phase microextraction of cadmium(II) using an ionic liquid as the extractant

    International Nuclear Information System (INIS)

    A method is presented for hollow fiber liquid-phase microextraction (HF-LPME) of cadmium(II), which is chelated with 1-(2-pyridylazo)-2-naphthol (PAN) to obtain a hydrophobic complex which then is extracted into a polypropylene hollow fiber containing an ionic liquid in its pores which acts as the membrane phase. EDTA is then injected into the lumen of the membrane as an acceptor phase to trap the analyte. The extraction time (20 min), agitation (400 rpm at 25 °C), pH value (10.0), and the concentrations of PAN (2.5 ng mL−1) and EDTA (250 ng mL−1) were optimized. With a sample volume of 50 mL and a stripping volume of 15 μL, the enrichment factor is 162. Cadmium(II) was then quantified by graphite furnace AAS. The limit of detection is 0.12 pg mL−1, the relative standard deviation is 5.2 %, and the linear working range extends from 4 to 45 pg mL−1. The method was successfully applied to the determination of Cd(II) in environmental and food samples. (author)

  3. Fabrication and formation mechanism of poly (L-lactic acid ultrafine multi-porous hollow fiber by electrospinning

    Directory of Open Access Journals (Sweden)

    Q. Z. Yu

    2013-01-01

    Full Text Available Poly(L-lactic acid (PLLA ultrafine multi-porous hollow fibers are fabricated by electrospinning with methylene dichloride as solvent. The Kirkendall effect has been widely applied for the fabrication of hollow structure in metals and inorganic materials. In this study, a conceptual extension is proposed for the formation mechanism: the development of porous hollow fiber undergoes three stages. The initial stage is the generation of small voids or pits on the surface of the fiber via surface diffusion and phase separation; the second stage is the formation of multi-pores penetrating the core of the fiber through the interaction of Kirkendall effect, surface diffusion and phase separation; the third stage is dominated by surface diffusion of the core material along the pore surface. To explore the formation conditions, the factors including ambient temperature, relativity humidity (R. H., molecular weight and fiber diameter are studied. The longitudinal and cross sectional morphologies of these fibers are examined by scanning electron micrograph (SEM. The results show that the prerequisite for the formation of uniform porous hollow PLLA fibers include moderate ambient temperature (10~20°C and appropriate molecular weight for the PLLA, as well as the diameter of the fiber in the range of several micrometers to about 100 nanometers.

  4. Synthesis of ceramic hollow fiber supported zeolitic imidazolate framework-8 (ZIF-8) membranes with high hydrogen permeability

    KAUST Repository

    Pan, Yichang

    2012-12-01

    Purification and recovery of hydrogen from hydrocarbons in refinery streams in the petrochemical industry is an emerging research field in the study of membrane gas separation. Hollow fiber membrane modules can be easily implemented into separation processes at the industrial scale. In this report, hollow yttria-stabilized zirconia (YSZ) fiber-supported zeolitic imidazole framework-8 (ZIF-8) membranes were successfully prepared using a mild and environmentally friendly seeded growth method. Our single-component permeation studies demonstrated that the membrane had a very high hydrogen permeance (~15×10 -7mol/m 2sPa) and an ideal selectivity of H 2/C 3H 8 of more than 1000 at room temperature. This high membrane permeability and selectivity caused serious concentration polarization in the separation of H 2/C 3H 8 mixtures, which led to almost 50% drop in both the H 2 permeance and the separation factor. Enhanced mixing on the feed side could reduce the effect of the concentration polarization. Our experimental data also indicated that the membranes had excellent reproducibility and long-term stability, indicating that the hollow fiber-supported ZIF-8 membranes developed in this study have great potential in industry-scale separation of hydrogen. © 2012 Elsevier B.V.

  5. Experimental study on the separation of CO2 from flue gas using hollow fiber membrane contactors without wetting

    International Nuclear Information System (INIS)

    Experiments on CO2 removal from flue gas using polypropylene (PP) hollow fiber membrane contactors were conducted in this study. Absorbents including aqueous potassium glycinate (PG) solution, aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) were used to absorb CO2 in the experiments. Based on the wetting experimental results, aqueous PG solution can offer a higher surface tension than water, aqueous MEA and MDEA solutions. Aqueous PG solution has a lower potential of membrane wetting after a continuously steady operation for 40 h to maintain CO2 removal efficiency of about 90%. Under moderate operating conditions, effects of the temperature, flow rate, and concentration of absorbents, and the flow rate of flue gas as well as the volumetric concentration of carbon dioxide in the flue gas on the mass transfer rate of CO2 were studied on a pilot-scale test facility. Unlike conventional absorbents, the mass transfer decreases with an increasing liquid temperature when using aqueous PG solution. Results show that CO2 removal efficiency was above 90% and the mass transfer rate was above 2.0 mol/(m2 h) using the PG aqueous solution. It indicates that the hollow fiber membrane contactor has a great potential in the area of CO2 separation from flue gas when absorbent's concentration and liquid-gas pressure difference are designed elaborately. (author)

  6. Fabrication of Collagen Gel Hollow Fibers by Covalent Cross-Linking for Construction of Bioengineering Renal Tubules.

    Science.gov (United States)

    Shen, Chong; Zhang, Guoliang; Wang, Qichen; Meng, Qin

    2015-09-01

    Collagen, the most used natural biomacromolecule, has been extensively utilized to make scaffolds for cell cultures in tissue engineering, but has never been fabricated into the configuration of a hollow fiber (HF) for cell culture due to its poor mechanical properties. In this study, renal tubular cell-laden collagen hollow fiber (Col HF) was fabricated by dissolving sacrificial Ca-alginate cores from collagen shells strengthened by carbodiimide cross-linking. The inner/outer diameters of the Col HF were precisely controlled by the flow rates of core alginate/shell collagen solution in the microfluidic device. As found, the renal tubular cells self-assembled into renal tubules with diameters of 50-200 μm post to the culture in Col HF for 10 days. According to the 3D reconstructed confocal images or HE staining, the renal cells appeared as a tight tubular monolayer on the Col HF inner surface, sustaining more 3D cell morphology than the cell layer on the 2D flat collagen gel surface. Moreover, compared with the cultures in either a Transwell or polymer HF membrane, the renal tubules in Col HF exhibited at least 1-fold higher activity on brush border enzymes of alkaline phosphatase and γ-glutamyltransferase, consistent with their gene expressions. The enhancement occurred similarly on multidrug resistance protein 2 and glucose uptake. Such bioengineered renal tubules in Col HF will present great potential as alternatives to synthetic HF in both clinical use and pharmaceutical investigation. PMID:26280545

  7. Modification of Polyethersulfone Hollow Fiber Membranes by Novel Charged Surface Modifying Macromolecule (cSMM) Blends for Water Application

    Science.gov (United States)

    Bolong, N.; Ismail, A. F.; Salim, M. R.; Rana, D.; Matsuura, T.

    2009-06-01

    The analysis on modification of the polyethersulfone hollow fiber membranes by blending with Surface Modifying Macromolecules (SMMs) with end-groups of Aromatic sulfonate or aromatic benzoate for introducing charges at membrane surface is presented. The charged SMMs (cSMM) was synthesized and blended into the dope solution of polyethersulfone (PES) membranes. The synthesized cSMM was dissolved into the dope solution which consists of PES using N-methyl-2-pyrrolidone (NMP) as solvent. The membranes are prepared by phase inversion technique with the dry-wet hollow fiber spinning condition. The morphology of the fabricated membranes was observed from the Field Emission Scanning Electron Microscopy (FESEM). The FESEM observation did not show significant difference due to cSMM modification indicated the base polymer remained relatively unchanged. The miscibility and existence of cSMM in PES membrane was then confirmed via Fourier transform infra-red (FTIR) scan. The increase of pure water permeation performance of the modified membranes than the unmodified membranes was also observed.

  8. In-line sample concentration by evaporation through porous hollow fibers and micromachined membranes embedded in microfluidic devices.

    Science.gov (United States)

    Zhang, Hainan; Tiggelaar, Roald M; Schlautmann, Stefan; Bart, Jacob; Gardeniers, Han

    2016-02-01

    Two types of microfluidic systems, a porous hollow fiber and a thin supported membrane with an array of micromachined holes, are investigated for concentrating mass-limited analyte samples. Water evaporation is driven by the partial pressure difference across the hydrophobic membrane, induced by dry sweeping gas on the permeate side. An analytical model permitting clarification of the contribution of design and process parameters on acquisition of concentrated solution and prediction of achievable concentration factors is presented. Concentrating an exemplary solution utilizing the two systems has been studied at different experimental conditions to validate the model. The results show that the hollow fiber gives controllable concentration factors of more than 10. For the micromachined membrane concentrator concentration factors of 6-8 were achieved, at much lower flow rates than predicted by the model. Because of the asymptotic dependence of concentration factor on flow rate, accurate control of the liquid feed is extremely critical in the flow rate range where high concentration factors are obtained, and the smallest variations in liquid flow rate may easily lead to supersaturation and deposition of solutes in the pores. This changes membrane porosity in an unpredictable way and limits the maximum attainable concentration factor. PMID:26331575

  9. Experimental study on the separation of CO{sub 2} from flue gas using hollow fiber membrane contactors without wetting

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shui-ping; Fang, Meng-Xiang; Zhang, Wei-Feng; Luo, Zhong-Yang; Cen, Ke-Fa [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China); Wang, Shu-Yuan; Xu, Zhi-Kang [Institute of Polymer Science, Zhejiang University, Hangzhou 310027 (China)

    2007-05-15

    Experiments on CO{sub 2} removal from flue gas using polypropylene (PP) hollow fiber membrane contactors were conducted in this study. Absorbents including aqueous potassium glycinate (PG) solution, aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) were used to absorb CO{sub 2} in the experiments. Based on the wetting experimental results, aqueous PG solution can offer a higher surface tension than water, aqueous MEA and MDEA solutions. Aqueous PG solution has a lower potential of membrane wetting after a continuously steady operation for 40 h to maintain CO{sub 2} removal efficiency of about 90%. Under moderate operating conditions, effects of the temperature, flow rate, and concentration of absorbents, and the flow rate of flue gas as well as the volumetric concentration of carbon dioxide in the flue gas on the mass transfer rate of CO{sub 2} were studied on a pilot-scale test facility. Unlike conventional absorbents, the mass transfer decreases with an increasing liquid temperature when using aqueous PG solution. Results show that CO{sub 2} removal efficiency was above 90% and the mass transfer rate was above 2.0 mol/(m{sup 2} h) using the PG aqueous solution. It indicates that the hollow fiber membrane contactor has a great potential in the area of CO{sub 2} separation from flue gas when absorbent's concentration and liquid-gas pressure difference are designed elaborately. (author)

  10. In situ derivatization and hollow fiber membrane microextraction for gas chromatographic determination of haloacetic acids in water

    International Nuclear Information System (INIS)

    An alternative method for gas chromatographic determination of haloacetic acids (HAAs) in water using direct derivatization followed by hollow fiber membrane liquid-phase microextraction (HF-LPME) has been developed. The method has improved the sample preparation step according to the conventional US EPA Method 552.2 by combining the derivatization and the extraction into one step prior to determination by gas chromatography electron captured detector (GC-ECD). The HAAs were derivatized with acidic methanol into their methyl esters and simultaneously extracted with supported liquid hollow fiber membrane in headspace mode. The derivatization was attempted directly in water sample without sample evaporation. The HF-LPME was performed using 1-octanol as the extracting solvent at 55 deg. C for 60 min with 20% Na2SO4. The linear calibration curves were observed for the concentrations ranging from 1 to 300 μg L-1 with the correlation coefficients (R2) being greater than 0.99. The method detection limits of most analytes were below 1 μg L-1 except DCAA and MCAA that were 2 and 18 μg L-1, respectively. The recoveries from spiked concentration ranged from 97 to 109% with %R.S.D. less than 12%. The method was applied for determination of HAAs in drinking water and tap water samples. The method offers an easy one step high sample throughput sample preparation for gas chromatographic determination of haloacetic acids as well as other contaminants in water

  11. New 3-dimensional CFD modeling of CO2 and H2S simultaneous stripping from water within PVDF hollow fiber membrane contactor

    Science.gov (United States)

    Bahlake, Ahmad; Farivar, Foad; Dabir, Bahram

    2016-07-01

    In this paper a 3-dimensional modeling of simultaneous stripping of carbon dioxide (CO2) and hydrogen sulfide (H2S) from water using hollow fiber membrane made of polyvinylidene fluoride is developed. The water, containing CO2 and H2S enters to the membrane as feed. At the same time, pure nitrogen flow in the shell side of a shell and tube hollow fiber as the solvent. In the previous methods of modeling hollow fiber membranes just one of the membranes was modeled and the results expand to whole shell and tube system. In this research the whole hollow fiber shell and tube module is modeled to reduce the errors. Simulation results showed that increasing the velocity of solvent flow and decreasing the velocity of the feed are leads to increase in the system yield. However the effect of the feed velocity on the process is likely more than the influence of changing the velocity of the gaseous solvent. In addition H2S stripping has higher yield in comparison with CO2 stripping. This model is compared to the previous modeling methods and shows that the new model is more accurate. Finally, the effect of feed temperature is studied using response surface method and the operating conditions of feed temperature, feed velocity, and solvent velocity is optimized according to synergistic effects. Simulation results show that, in the optimum operating conditions the removal percentage of H2S and CO2 are 27 and 21 % respectively.

  12. New 3-dimensional CFD modeling of CO2 and H2S simultaneous stripping from water within PVDF hollow fiber membrane contactor

    Science.gov (United States)

    Bahlake, Ahmad; Farivar, Foad; Dabir, Bahram

    2015-08-01

    In this paper a 3-dimensional modeling of simultaneous stripping of carbon dioxide (CO2) and hydrogen sulfide (H2S) from water using hollow fiber membrane made of polyvinylidene fluoride is developed. The water, containing CO2 and H2S enters to the membrane as feed. At the same time, pure nitrogen flow in the shell side of a shell and tube hollow fiber as the solvent. In the previous methods of modeling hollow fiber membranes just one of the membranes was modeled and the results expand to whole shell and tube system. In this research the whole hollow fiber shell and tube module is modeled to reduce the errors. Simulation results showed that increasing the velocity of solvent flow and decreasing the velocity of the feed are leads to increase in the system yield. However the effect of the feed velocity on the process is likely more than the influence of changing the velocity of the gaseous solvent. In addition H2S stripping has higher yield in comparison with CO2 stripping. This model is compared to the previous modeling methods and shows that the new model is more accurate. Finally, the effect of feed temperature is studied using response surface method and the operating conditions of feed temperature, feed velocity, and solvent velocity is optimized according to synergistic effects. Simulation results show that, in the optimum operating conditions the removal percentage of H2S and CO2 are 27 and 21 % respectively.

  13. A controlled wet-spinning and dip-coating process for preparation of high-permeable TiO2 hollow fiber membranes.

    Science.gov (United States)

    Zhang, Qi; Wang, Hua; Fan, Xinfei; Chen, Shuo; Yu, Hongtao; Quan, Xie

    2016-01-01

    In order to improve the permeate flux of photocatalytic membranes, we present an approach for coupling TiO2 with ceramic hollow fiber membranes. The ceramic hollow fiber membranes with high permeate flux were fabricated by a controlled wet-spinning process using polyethersulfone (PESf) and ceramic powder as precursors and 1-methyl-2-pyrrolidinone as solvent, and the subsequent TiO2 coating was performed by a dip-coating process using tetra-n-butyl titanate as precursor. It has been found that the PESf/ceramic powder ratio could influence the structure of the membranes. Here the as-prepared TiO2 hollow fiber membranes had a pure water flux of 4,450 L/(m(2)·h). The performance of the TiO2 hollow fiber membrane was evaluated using humic acid (HA) as a test substance. The results demonstrated that this membrane exhibited a higher permeate flux under UV irradiation than in the dark and the HA removal efficiency was enhanced. The approach described here provides an operable route to the development of high-permeable photocatalytic membranes for water treatment. PMID:26901713

  14. Dual layer hollow fiber PVDF ultra-filtration membranes containing Ag nano-particle loaded zeolite with longer term anti-bacterial capacity in salt water.

    Science.gov (United States)

    Shi, Huyan; Xue, Lixin; Gao, Ailin; Zhou, Qingbo

    2016-01-01

    Dual layer polyvinylidene fluoride (PVDF), antibacterial, hollow fiber, ultra-filtration composite membranes with antibacterial particles (silver (Ag) nano-particles loaded zeolite (Z-Ag)) in the outer layer were prepared with high water flux and desired pore sizes. The amounts of Ag(+) released from the composite membranes, freshly made and stored in water and salt solution, were measured. The result indicated that dual layer PVDF antibacterial hollow fiber containing Z-Ag (M-1-Ag) still possessed the ability of continuous release of Ag(+) even after exposure to water with high ionic content, showing a longer term resistance to bacterial adhesion and antibacterial activity than membrane doped with Z-Ag(+) (M-1). Results from an anti-adhesion and bacteria killing test with Escherichia coli supported that the antibacterial efficiency of dual hollow fiber PVDF membranes with Z-Ag was much higher than those with Z-Ag(+) after long time storage in water or exposure to phosphate buffered saline (PBS) solution. This novel hollow fiber membrane may find applications in constructing sea water pretreatment devices with long term antifouling capability for the desalination processes. PMID:27148717

  15. Hollow fiber membrane contactors for CO2 capture: modeling and up-scaling to CO2 capture for an 800 MWe coal power station

    NARCIS (Netherlands)

    Kimball, E.; Al-Azki, A.; Gomez, A.; Goetheer, E.L.V.; Booth, N.; Adams, D.; Ferre, D.

    2014-01-01

    A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM) with the more conventional structured packing columns as the absorber in amine-based CO2capture systems for power plants. In order to simulate the operation of industrial scale HFMMsystems, a two-dime

  16. Porcine acute liver failure model established by two-phase surgery and treated with hollow fiber bioartificial liver support system

    Institute of Scientific and Technical Information of China (English)

    Yi Gao; Ning Mu; Xiao-Ping Xu; Yan Wang

    2005-01-01

    AIM: To establish a highly reproducible animal model of acute liver failure (ALF), for assessing theeffect of bioartificial liver support system (BALSS).METHODS: A two-phase complete liver devascularization procedure was performed in eight loco-hybrid pigs. Blood biochemical index and liver biopsy were studied every 2 h after surgery, and survival time was recorded. The BALSS constructed with high volume recirculating technique was a hollow fiber circulating system consisting of a hepatocyte reactor-hollow fiber module inoculated with microcarrieradhering hepatocytes, and a double pump, heparinized,thermostabilized, micro-capsulized activated carbonadsorbing plasmapheresis system. Twelve pigs undergoing two-phase surgery were randomized into: control group (perfused without hepatocytes, n = 6) and treatment group (perfused with hepatocytes, n = 6). Intergroup liver biochemical indexes, survival time, and liver pathological changes were analyzed at regular intervals.RESULTS: Two-phase surgery was performed in all the experimental pigs, and there was no obvious difference between their biochemical indexes. After 3 h of phase Ⅱ surgery, ammonia (Amm) increased to (269±37) μmol/L.After 5 h of the surgery, fibrinogen (Fib) decreased to (1.5±0.2) g/L. After 7 h of the surgery, ALT, AST, Tbil and PT were (7.6±1.8) nka/L, (40±5) nka/L, (55±8) μmol/L and (17.5±1.7) nka/L respectively. After 9 h of surgery, ALB and Cr were (27±4) g/L and (87±9) μmol/L. After 13 h of surgery, BUN was (3.5±0.9) μmol/L. All the above values were different from those determined before surgery.Survival time of pigs averaged 13.5±1.4 h. ALF pigs in the other group were treated with BALSS. The comparison analysis between the treated and control animals showed the changes of Tbil, PT, Alb, BUN, Cr, Fib, and Amm (P<0.01), but there was no change of ALT and AST. The survival time was statistically different (P<0.01), and there was no significant difference in histological changes

  17. Resistance to protein and oil fouling of sulfobetaine-grafted Poly(vinylidene Fluoride) hollow fiber membrane and the electrolyte-responsive behavior in NaCl solution

    Science.gov (United States)

    Li, Qian; Bi, Qiu-Yan; Liu, Tian-Yin; Wang, Xiao-Lin

    2012-07-01

    An excellent protein-fouling-resistance performance of the sulfobetaine-grafted PVDF hollow fiber membrane was obtained and the potential of sulfobetaine-grafted PVDF membrane to resist the oil fouling was confirmed in the filtration solution which contained inorganic electrolyte, sodium chloride (NaCl). The electrolyte-responsive behavior of the sulfobetaine-modified PVDF membrane was demonstrated by the filtration of NaCl aqueous solution. The grafting amount of the modified PVDF hollow fiber membrane showed a stable value as 680 μg/cm2. An almost complete coverage of the membrane surface by the grafted sulfobetaine polymer contributed to the high hydrophilicity and membrane strength. The membrane surface became denser and the permeate flux reduced with the increase of NaCl concentration. The cyclic filtration experiment showed that during the filtration of the protein solution with 0.05 mol/L of NaCl, the sulfobetaine-grafted PVDF membrane exhibited an excellent protein-fouling-resistance performance with a high relative flux recovery of 98.2% and a low irreversible fouling extent which was lower 10 times than that of the nascent PVDF hollow fiber membrane. In addition, the sulfobetaine-grafted PVDF hollow fiber membrane showed an oil-fouling-resistance property during the filtration experiment of the oil-in-water emulsion with 0.05 mol/L of NaCl, resulting in an relative flux recovery of about twice that of the nascent PVDF membrane. The results extended the application of poly(sulfobetaine)-g-PVDF hollow fiber membrane in the fields of bio-separation, artificial oil and wastewater treatment.

  18. Reduction of the barium concentration presents in liquid effluents by mean of non-dispersive extraction in hollow fiber modules

    International Nuclear Information System (INIS)

    This work has been focused on the study of the viability of barium removal, present in a waste liquid phase, by means of non-dispersive extraction (NDE) in hollow fiber modules. An organic solution based on DEPHA (Bis-2-ethylhexyl phosphate) 30% (v/v), isopropilic alcohol 30% (v/v) and kerosene is used as selective extraction medium. For the extraction process was made a contactor with five hollow microporous propilenic fibers. A solution contained 100 ppm of BaCl2 H2O, level concentration very equal as generated on the petroleum industrial wastes, is used as liquid phase. a efficiency of 95,25% is obtained when the NDE take place at pH = 9, and them 9 hours of process

  19. Composite polymer/oxide hollow fiber contactors: versatile and scalable flow reactors for heterogeneous catalytic reactions in organic synthesis.

    Science.gov (United States)

    Moschetta, Eric G; Negretti, Solymar; Chepiga, Kathryn M; Brunelli, Nicholas A; Labreche, Ying; Feng, Yan; Rezaei, Fateme; Lively, Ryan P; Koros, William J; Davies, Huw M L; Jones, Christopher W

    2015-05-26

    Flexible composite polymer/oxide hollow fibers are used as flow reactors for heterogeneously catalyzed reactions in organic synthesis. The fiber synthesis allows for a variety of supported catalysts to be embedded in the walls of the fibers, thus leading to a diverse set of reactions that can be catalyzed in flow. Additionally, the fiber synthesis is scalable (e.g. several reactor beds containing many fibers in a module may be used) and thus they could potentially be used for the large-scale production of organic compounds. Incorporating heterogeneous catalysts in the walls of the fibers presents an alternative to a traditional packed-bed reactor and avoids large pressure drops, which is a crucial challenge when employing microreactors. PMID:25865826

  20. Modeling the Transverse Shell-side Mass Transfer in Hollow Fiber Membrane Contactors at Low Reynolds Numbers

    Science.gov (United States)

    Kirsch, V. A.; Volkov, V. V.; Bildukevich, A. V.

    A method for calculating the external mass transfer in a contactor with a transverse confined flow of a viscous incompressible liquid (gas) past hollow fibers at low Reynolds numbers is proposed. The method is based on the concept of regular arrays of parallel fibers with a well-defined flowfield. As a simplest model system, a row of parallel fibers is considered, for which dependences of a drag force and an efficiency of a solute retention on the inter-fiber distance, membrane mass transfer coefficient, Peclet and Reynolds numbers are computed. The influence of the fluid inertia on the mass transport is studied. It is shown that a linear Stokes equations can be used for as higher Re numbers, as denser is the fiber array. In this case the flow field is independent on the Re number, and analytical solutions for the flowfield and fiber sorption efficiency (fiber Sherwood number) can be used.

  1. Incompressible laminar flow through hollow fibers: a general study by means of a two-scale approach

    Science.gov (United States)

    Borsi, Iacopo; Farina, Angiolo; Fasano, Antonio

    2011-08-01

    We study the laminar flow of an incompressible Newtonian fluid in a hollow fiber, whose walls are porous. We write the Navier-Stokes equations for the flow in the inner channel and Darcy's law for the flow in the fiber, coupling them by means of the Beavers-Joseph condition which accounts for the (possible) slip at the membrane surface. Then, we introduce a small parameter {\\varepsilon ≪ 1} (the ratio between the radius and the length of the fiber) and expand all relevant quantities in powers of ɛ. Averaging over the fiber cross section, we find the velocity profiles for the longitudinal flow and for the cross-flow, and eventually, we determine the explicit expression of the permeability of the system. This work is also preliminary to the study of more complex systems comprising a large number of identical fibers (e.g., ultrafiltration modules and dialysis).

  2. Improvement of Separation of Polystyrene Particles with PAN Membranes in Hollow Fiber Flow Field-Flow Fractionation

    International Nuclear Information System (INIS)

    Hollow Fiber flow field-flow fractionation (HF-FlFFF) has been tested in polyacrylonitrile (PAN) membrane channel in order to compare it with polysulfone (PSf) membrane channel. It has been experimentally shown that the separation time of 0.05-0.304 μm polystyrene latex (PSL) standards in PAN membrane channel is shorter than that in PSf channel by approximately 65%. The optimized separation condition in PAN membrane is Vout/ Vrad = 1.4/0.12 mL/min, which is equal to the condition in PSf membrane channel. In addition both the resolution (Rs) and plate height (H) in PAN membrane channel are better than that in PSf membrane channel. The membrane radius was obtained by back calculation with retention time. It shows that the PSf membrane is expanded by swelling and pressure, but the PAN membrane doesn't expand by swelling and pressure

  3. Quantitative PVP mapping in PVDF hollow fiber membranes by using Raman spectroscopy coupled with spectral chemiometrics analysis

    Science.gov (United States)

    Dufour, E.; Gassara, S.; Petit, E.; Pochat-Bohatier, C.; Deratani, A.

    2015-07-01

    Fabrication of fouling resistant UF membranes requires the use of hydrophilic polymer additives that must be trapped in the polymer matrix during the phase separation processing. The knowledge of the polymeric additive distribution across the whole thickness should help to the design of more efficient membranes. This paper aims at developing a new methodology based on Raman microscopy spectroscopy owing to its high spatial resolution. A UF hollow fiber made from a blend of PVDF as polymer matrix and PVP as additive was chosen as a model membrane for this study. The PVP concentration profile along the cross-section radial axis was determined by using two ways of spectrum treatment including the analytical method by the peak intensity ratio calculation and a multivariate analysis with a partial least-squares regression model. The feasibility of the two approaches was discussed.

  4. Bioreduction of para-chloronitrobenzene in drinking water using a continuous stirred hydrogen-based hollow fiber membrane biofilm reactor

    International Nuclear Information System (INIS)

    Highlights: → We designed a novel hollow fiber membrane biofilm reactor for p-CNB removal. → Biotransformation pathway of p-CNB in the reactor was investigated in this study. → Nitrate and sulfate competed more strongly for hydrogen than p-CNB. → This reactor achieved high removal efficiency and hydrogen utilization efficiency. - Abstract: para-Chloronitrobenzene (p-CNB) is particularly harmful and persistent in the environment and is one of the priority pollutants. A feasible degradation pathway for p-CNB is bioreduction under anaerobic conditions. Bioreduction of p-CNB using a hydrogen-based hollow fiber membrane biofilm reactor (HFMBfR) was investigated in the present study. The experiment results revealed that p-CNB was firstly reduced to para-chloraniline (p-CAN) as an intermediate and then reduced to aniline that involves nitro reduction and reductive dechlorination with H2 as the electron donor. The HFMBfR had reduced p-CNB to a major extent with a maximum removal percentage of 99.3% at an influent p-CNB concentration of 2 mg/L and a hydraulic residence time of 4.8 h, which corresponded to a p-CNB flux of 0.058 g/m2 d. The H2 availability, p-CNB loading, and the presence of competing electron acceptors affected the p-CNB reduction. Flux analysis indicated that the reduction of p-CNB and p-CAN could consume fewer electrons than that of nitrate and sulfate. The HFMBfR had high average hydrogen utilization efficiencies at different steady states in this experiment, with a maximum efficiency at 98.2%.

  5. Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

    Science.gov (United States)

    Lunn, Griffin; Wheeler, Raymond; Hummerick, Mary; Birmele, Michele; Richards, Jeffrey; Coutts, Janelle; Koss, Lawrence; Spencer, Lashelle.; Johnsey, Marissa; Ellis, Ronald

    Bioreactor research, even today, is mostly limited to continuous stirred-tank reactors (CSTRs). These are not an option for microgravity applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. This has led to testing of Hollow Fiber Membrane Bioreactors (HFMBs) for microgravity applications, including possible use for wastewater treatment systems for the International Space Station (ISS). Bioreactors and filtration systems for treating wastewater could avoid the need for harsh pretreatment chemicals and improve overall water recovery. However, the construction of these reactors is difficult and commercial off-the-shelf (COTS) versions do not exist in small sizes. We have used 1-L modular HFMBs in the past, but the need to perform rapid testing has led us to consider even smaller systems. To address this, we designed and built 125-mL, rectangular reactors, which we have called the Fiber Attachment Module Experiment (FAME) system. A polycarbonate rack of four square modules was developed with each module containing removable hollow fibers. Each FAME reactor is self-contained and can be easily plumbed with peristaltic and syringe pumps for continuous recycling of fluids and feeding, as well as fitted with sensors for monitoring pH, dissolved oxygen, and gas measurements similar to their larger counterparts. The first application tested in the FAME racks allowed analysis of over a dozen fiber surface treatments and three inoculation sources to achieve rapid reactor startup and biofilm attachment (based on carbon oxidation and nitrification of wastewater). With these miniature FAME reactors, data for this multi-factorial test were collected in duplicate over a six-month period; this greatly compressed time period required for gathering data needed to study and improve bioreactor performance.

  6. Water reclamation from emulsified oily wastewater via effective forward osmosis hollow fiber membranes under the PRO mode.

    Science.gov (United States)

    Han, Gang; de Wit, Jos S; Chung, Tai-Shung

    2015-09-15

    By using a novel hydrophilic cellulose acetate butyrate (CAB) as the membrane material for the hollow fiber substrate and modifying its outer surface by polydopamine (PDA) coating and inner surface by interfacial polymerization, we have demonstrated that the thin-film composite (TFC) membranes can be effectively used for sustainable water reclamation from emulsified oil/water streams via forward osmosis (FO) under the pressure retarded osmosis (PRO) mode. The newly developed TFC-FO hollow fiber membrane shows characteristics of high water flux, outstanding salt and oil rejection, and low fouling propensity. Under the PRO mode, the newly developed TFC-FO membrane exhibits a water flux of 37.1 L m(-2) h(-1) with an oil rejection of 99.9% using a 2000 ppm soybean oil/water emulsion as the feed and 1 M NaCl as the draw solution. Remarkable anti-fouling behaviors have also been observed. Under the PRO mode, the water flux decline is only 10% of the initial value even after a 12 h test for oil/water separation. The water flux of the fouled membrane can be effectively restored to 97% of the original value by water rinses on the fiber outer surface without using any chemicals. Furthermore, the flux declines are only 25% and 52% when the water recovery of a 2000 ppm soybean oil/water emulsion and a 2000 ppm petroleum oil/water emulsion containing 0.04 M NaCl reaches 82%, respectively. This study may not only provide insightful guidelines for the fabrication of effective TFC-FO membranes with high performance and low fouling behaviors for oily wastewater under the PRO mode but also add an alternative perspective to the design of new materials for water purification purposes. PMID:26043371

  7. Ionic liquid-based hollow fiber supported liquid membrane extraction combined with thermospray flame furnace AAS for the determination of cadmium

    International Nuclear Information System (INIS)

    We have developed a simple and effective method for hollow fiber liquid-phase microextraction of cadmium. It is based on the use of a room temperature ionic liquid (RTIL) and was coupled to thermospray flame furnace AAS. The RTIL was placed in the pores of a polypropylene hollow fiber (acting as a liquid membrane) and also used as the acceptor solution. Ammonium pyrrolidine dithiocarbamate (APDC) was used as the chelating agent. The effects of the concentration of APDC, the pH of samples, stirring rates, extraction time, and potential interferences were optimized to result in a detection limit of 9 ng L-1 and an enrichment factor of 90. The relative standard deviation is 4. 7% (at 0. 5 ng mL-1, for n = 5). The method was successfully applied to the determination of cadmium. (author)

  8. A Facile Method to Prepare Double-Layer Isoporous Hollow Fiber Membrane by In Situ Hydrogen Bond Formation in the Spinning Line.

    Science.gov (United States)

    Noor, Nazia; Koll, Joachim; Radjabian, Maryam; Abetz, Clarissa; Abetz, Volker

    2016-03-01

    A double-layer hollow fiber is fabricated where an isoporous surface of polystyrene-block-poly(4-vinylpyridine) is fixed on a support layer by co-extrusion. Due to the sulfonation of the support layer material, delamination of the two layers is suppressed without increasing the number of subsequent processing steps for isoporous composite membrane formation. Electron microscope-energy-dispersive X-ray spectroscopy images unveil the existence of a high sulfur concentration in the interfacial region by which in-process H-bond formation between the layers is evidenced. For the very first time, our study reports a facile method to fabricate a sturdy isoporous double-layer hollow fiber. PMID:26685710

  9. Effects of dope extrusion rate on the morphology and gas separation performance of asymmetric polysulfone hollow fiber membranes for O2/N2 separation

    Directory of Open Access Journals (Sweden)

    Ahmad Fausi Ismail

    2002-11-01

    Full Text Available The objective of this study was to investigate the influence of dope extrusion rates on morphology and gas separation performance of asymmetric polysulfone hollow fiber membranes. Asymmetric polysulfone hollow fiber membranes for gas separation were prepared from a solution consisting of 26.0 wt. % of polysulfone, 30.4 wt. % of N, N-dimethylacetamide, 30.4 wt. % of tetrahydrofuran and 13.2 wt. % ethanol. The dry/wet phase separation process was applied to a dry/wet spinning process. Fibers were spun at various dope extrusion rates (DER ranging from 1.5 - 3.0 cm3/min and hence at different levels of shear. The results suggest that as the dope extrusion rate is increased, the selectivity will increase until a critical level of shear is reached, beyond which the membrane performance deteriorates. Pressure-normalized-fluxes and selectivities were evaluated by using pure oxygen and nitrogen as test gases.

  10. Effect of Extractant and Cold-drawing on the Structure and Performance of HDPE Hollow Fiber Membranes Fabricated via Thermally Induced Phase Separation Method

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-li; RUAN Wen-xiang; SONG Yi-lin; JI Jian-bing; YAO Ke-jian

    2006-01-01

    Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS)method. Effects of extraction and cold-drawing condition on membrane structure and performance were investigated.Five volatile solvents were used as extractant. Dimension of hollow fiber and gas permeation rate of membrane were measured. Microstructure of membrane was examined by Scanning Electronic Microscope (SEM). The results show that the membrane treated by pentane possesses a higher porosity, nitrogen permeability and lower shrinkage than those of membranes extracted by other three extractants. It is also found that thc membrane stretched 133% shows the highest porosity and gas permeability in this study.

  11. Low-temperature, low-cost growth of robust ATR GeO2 hollow fibers based on copper capillary tubes for transmission of CO2 laser light

    Science.gov (United States)

    Jing, Chengbin; Bai, Wei; Hu, Zhigao; Yang, Pingxiong; Liu, Aiyun; Lin, Fangtin; Shi, Yiwei; Chu, Junhao

    2014-02-01

    Attenuated total reflectance (ATR) infrared hollow waveguide attracts particular interest since it has both advantages of a hollow fiber and a light guiding mechanism similar to that of solid-core fibers. Presently, ATR hollow waveguides are mainly structured with single-crystal sapphire or glassy materials. These waveguides are somewhat brittle. More robust ATR hollow fibers are required in many military and domestic applications. In this work, ATR GeO2 hollow waveguides were prepared based on a copper capillary tube for transmitting CO2 laser light. The inner wall of the copper structural tube was polished using a high-pressure pulsed nanofluid technique. A hexagonal crystalline GeO2 reflective layer with sufficient thickness (>4 μm) was grown on the inner tube wall via a simple liquid phase deposition process at room temperature. The GeO2 coated copper hollow fiber exhibits a low-loss band within 10-11.5 μm. It can still be bent since the hollow-core size (1.4 mm) and the wall thickness (50 μm) are not too large. The transmissions of CO2 laser light are 91% and 43% under a straight condition and a 90° bend with a 30-cm radius condition, respectively. The waveguide displays high heat-resisting properties due to high thermal conductivity of the copper substrate tube and a high melting point (1115°C) of the GeO2 reflective layer. This work opens a door for low-temperature, low-cost growth of long ATR GeO2 infrared hollow fibers based on various substrate tubes, even including plastic capillary tubes.

  12. Compression of CEP-stable multi-mJ laser pulses down to 4 fs in long hollow fibers

    International Nuclear Information System (INIS)

    Carrier–envelope phase stable 4 fs near-IR pulses with 3 mJ energy were generated by spectral broadening of circularly polarized 8 mJ pulses in a differentially pumped 2 m long composite stretched flexible hollow fiber. The pulses were characterized using both second-harmonic generation frequency-resolved optical gating (SHG-FROG) and SHG d-scan methods. (letter)

  13. Comparison of Hollow-Fiber Ultrafilters with Pleated Capsule Filters for Surface and Tap Water Samples Using U.S. EPA Method 1623

    OpenAIRE

    Kimble, Gina H.; Amburgey, James E.; Hill, Vincent R.

    2012-01-01

    The EPA method 1623 is designed specifically for the detection of Cryptosporidium and Giardia, but the method has some issues with low and variable recoveries. Ultrafiltration has been used effectively for microorganism recovery from water samples but is not approved by the EPA. To determine the efficacy of using ultrafiltration, 10-L tap water and surface water samples were seeded with Cryptosporidium and Giardia and concentrated with either a pleated capsule filter or a hollow-fiber ultrafi...

  14. Removal of humic acid by a new type of electrical hollow-fiber microfiltration (E-HFMF)

    Science.gov (United States)

    Shang, Ran; Deng, Hui-ping; Hu, Jing-yi

    2010-11-01

    Low pressure membrane filtration, such as microfiltration, was widely used in the field of drinking water purification in the past few decades. Traditional microfiltration membranes are not efficient enough in the removal of natural organic matters (NOM) from raw water. Moreover, they tend to be fouled by the NOM and the filtration age of the membranes is thus shrinked. To tackle these problems, a new type of electrical hollow-fiber microfiltration module (E-HFMF) was designed. In the E-HFMF module, the hollow-fiber microfiltration membranes were placed into the radialized electrical field which functioned from the centre to the exterior of the cylindrical cavity. The main goal of the present study was to evaluate the efficiency of E-HFMF to remove the humic acid (HA, one of the main components of NOM). According to the parallel tests compared with the traditional microfiltration, the removal rate of humic acid was raised to 70%˜85% in terms of UV-254 and to 60%˜75% in terms of DOC when filtrating with the E-HFMF, while the removal rates of humic acid were 10%˜20% and 1%˜10% respectively when filtrating with the traditional microfiltration. The negative charged humic acid moved to the anode because of the electrophoresis, so few humic acid could be able to permeate through the membrane. The electrophoresis mobility of the humic acid permeating through the traditional microfiltration decreased by 19%, while the same index from the E-HFMF decreased by 75%. This indicated that the electrophoresis played a significant role on removing the humic acid. According to the gel permeate chromatograph analysis, humic acid aggregated in an electric field and thus forms loose and permeable cake layer on the membrane surface, which also relieved membrane fouling. Meanwhile, the negative charged humic acid migrating to the anode at the center minimized the deposition onto the membrane surface, and eliminated the membrane fouling as a result. During the E-HFMF filtration, the

  15. The Fabrication of Ga2O3/ZSM-5 Hollow Fibers for Efficient Catalytic Conversion of n-Butane into Light Olefins and Aromatics

    Directory of Open Access Journals (Sweden)

    Jing Han

    2016-01-01

    Full Text Available In this study, the dehydrogenation component of Ga2O3 was introduced into ZSM-5 nanocrystals to prepare Ga2O3/ZSM-5 hollow fiber-based bifunctional catalysts. The physicochemical features of as-prepared catalysts were characterized by means of XRD, BET, SEM, STEM, NH3-TPD, etc., and their performances for the catalytic conversion of n-butane to produce light olefins and aromatics were investigated. The results indicated that a very small amount of gallium can cause a marked enhancement in the catalytic activity of ZSM-5 because of the synergistic effect of the dehydrogenation and aromatization properties of Ga2O3 and the cracking function of ZSM-5. Compared with Ga2O3/ZSM-5 nanoparticles, the unique hierarchical macro-meso-microporosity of the as-prepared hollow fibers can effectively enlarge the bifunctionality by enhancing the accessibility of active sites and the diffusion. Consequently, Ga2O3/ZSM-5 hollow fibers show excellent catalytic conversion of n-butane, with the highest yield of light olefins plus aromatics at 600 °C by 87.6%, which is 56.3%, 24.6%, and 13.3% higher than that of ZSM-5, ZSM-5 zeolite fibers, and Ga2O3/ZSM-5, respectively.

  16. Robust outer-selective thin-film composite polyethersulfone hollow fiber membranes with low reverse salt flux for renewable salinity-gradient energy generation

    KAUST Repository

    Cheng, Zhen Lei

    2016-01-08

    This study reports outer-selective thin-film composite (TFC) hollow fiber membranes with extremely low reverse salt fluxes and robustness for harvesting salinity-gradient energy from pressure retarded osmosis (PRO) processes. Almost defect-free polyamide layers with impressive low salt permeabilities were synthesized on top of robust polyethersulfone porous supports. The newly developed TFC-II membrane shows a maximum power density of 7.81 W m−2 using 1 M NaCl and DI water as feeds at 20 bar. Reproducible data obtained in the 2nd and 3rd runs confirm its stability under high hydraulic pressure differences. Comparing to other PRO membranes reported in the literature, the newly developed membrane exhibits not only the smallest slope between water flux decline and ΔPΔP increase but also the lowest ratio of reverse salt flux to water flux. Thus, the effective osmotic driving force could be well maintained even under high pressure operations. For the first time, the effect of feed pressure buildup induced by feed flowrate was evaluated towards PRO performance. A slight increment in feed pressure buildup was found to be beneficial to water flux and power density up to 10.06 W m−2 without comprising the reverse salt flux. We believe this study may open up new perspectives on outer-selective PRO hollow fiber membranes and provide useful insights to understand and design next-generation outer-selective TFC hollow fiber membranes for osmotic power generation.

  17. A low-cost mullite-titania composite ceramic hollow fiber microfiltration membrane for highly efficient separation of oil-in-water emulsion.

    Science.gov (United States)

    Zhu, Li; Chen, Mingliang; Dong, Yingchao; Tang, Chuyang Y; Huang, Aisheng; Li, Lingling

    2016-03-01

    Oil-in-water (O/W) emulsion is considered to be difficult to treat. In this work, a low-cost multi-layer-structured mullite-titania composite ceramic hollow fiber microfiltration membrane was fabricated and utilized to efficiently remove fine oil droplets from (O/W) emulsion. In order to reduce membrane cost, coal fly ash was effectively recycled for the first time to fabricate mullite hollow fiber with finger-like and sponge-like structures, on which a much more hydrophilic TiO2 layer was further deposited. The morphology, crystalline phase, mechanical and surface properties were characterized in details. The filtration capability of the final composite membrane was assessed by the separation of a 200 mg·L(-1) synthetic (O/W) emulsion. Even with this microfiltration membrane, a TOC removal efficiency of 97% was achieved. Dilute NaOH solution backwashing was used to effectively accomplish membrane regeneration (∼96% flux recovery efficiency). This study is expected to guide an effective way to recycle waste coal fly ash not only to solve its environmental problems but also to produce a high-valued mullite hollow fiber membrane for highly efficient separation application of O/W emulsion with potential simultaneous functions of pure water production and oil resource recovery. PMID:26748205

  18. Membrane solid phase microextraction with alumina hollow fiber on line coupled with ICP-OES for the determination of trace copper, manganese and nickel in environmental water samples

    International Nuclear Information System (INIS)

    A novel alumina hollow fiber was synthesized by sol-gel template method and was characterized by scanning electron microscopy, N2 adsorption technique and X-ray diffraction. With the use of prepared alumina hollow fiber as extraction membrane, a new method of flow injection (FI)-membrane solid phase microextraction (MSPME) on-line coupled to inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for simultaneous determination of trace metals (Cu, Mn and Ni) in environmental water samples. The adsorption capacities of the alumina hollow fiber for Cu, Mn and Ni were found to be 6.6, 8.7 and 13.3 mg g-1, respectively. With a preconcentration factor of 10, the limits of detection (LODs) for Cu, Mn and Ni were found to be 0.88, 0.61 and 0.38 ng mL-1, respectively, and the relative standard deviations (RSDs) were ranging from 6.2 to 7.9% (n = 7, c = 10 ng mL-1). To validate the accuracy, the proposed method was applied to the analysis of certified reference material GSBZ50009-88 environmental water and the determined values are in good agreement with the certified values. The developed method was also employed for the analysis of Yangtze River water and East Lake water, and the recoveries for the spiked samples were in the range of 87.4-110.2%.

  19. NIPS法制备PVDF中空纤维膜的研究进展%Progress in Preparation of PVDF Hollow Fiber Membranes by NIPS Method

    Institute of Scientific and Technical Information of China (English)

    董绍春; 刘慧; 徐建明; 方敏; 吁苏云

    2014-01-01

    介绍了非溶剂致相分离(NIPS)法制备聚偏氟乙烯(PVDF)中空纤维膜的研究进展,其中包括:溶剂类型、PVDF树脂性能,添加剂类型,凝胶浴的类型和温度、后处理工艺等因素对PVDF中空纤维膜结构和性能的影响。最后,对NIPS法制备PVDF中空纤维膜进行了总结和展望。%This paper focused on progress in preparation of PVDF hollow fiber membranes by non-sol-vent induced phase separation (NIPS) method, especially the effects of the solvent, PVDF resin properties, ad-ditive types, coagulation bath type, coagulation temperature, post-treatment on the structure and properties of PVDF hollow fiber membranes. Finally, PVDF hollow fiber membranes made by NIPS technique were also summarized and prospected.

  20. Effect of Diluent on the Morphology and Performance of IPP Hollow Fiber Microporous Membrane via Thermally Induced Phase Separation%热致相分离法iPP中空纤维微空膜结构与性能--稀释剂的作用

    Institute of Scientific and Technical Information of China (English)

    杨振生; 李凭力; 常贺英; 王世昌

    2006-01-01

    Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared using thermally induced phase separation (TIPS) method. Di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), and the mixed solvent were used as diluents. The effect of α (DOP mass fraction in diluent) on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.

  1. A heat pump driven and hollow fiber membrane-based liquid desiccant air dehumidification system: Modeling and experimental validation

    International Nuclear Information System (INIS)

    A compression heat pump driven and membrane-based liquid desiccant air dehumidification system is presented. The dehumidifier and the regenerator are made of two hollow fiber membrane bundles packed in two shells. Water vapor can permeate through these membranes effectively, while the liquid desiccant droplets are prevented from cross-over. Simultaneous heating and cooling of the salt solution are realized with a heat pump system to improve energy efficiency. In this research, the system is built up and a complete modeling is performed for the system. Heat and mass transfer processes in the membrane modules, as well as in the evaporator, the condenser, and other key components are modeled in detail. The whole model is validated by experiment. The performances of SDP (specific dehumidification power), dehumidification efficiency, EER (energy efficiency ratio) of heat pump, and the COP (coefficient of performance) of the system are investigated numerically and experimentally. The results show that the model can predict the system accurately. The dehumidification capabilities and the energy efficiencies of the system are high. Further, it performs well even under the harsh hot and humid South China weather conditions. - Highlights: • A membrane-based and heat pump driven air dehumidification system is proposed. • A real experimental set up is built and used to validate the model for the whole system. • Performance under design and varying operation conditions is investigated. • The system performs well even under harsh hot and humid conditions

  2. Radiosynthesis of hydrogel confined to hollow-fiber membranes for the design of a bioartificial extra-corporeal liver

    International Nuclear Information System (INIS)

    Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic permeability and diffusion of glucose, albumin and IgG were measured in these hydrogel-filled membranes. Polyacrylamide 0.5 M showed the best compromise between albumin diffusion (1.2x10-7 cm2/s) and HSA/IgG selectivity (2.2)

  3. High-throughput hydrolysis of starch during permeation across α-amylase-immobilized porous hollow-fiber membranes

    International Nuclear Information System (INIS)

    Two kinds of supporting porous membranes, ethanolamine (EA) and phenol (Ph) fibers, for immobilization of α-amylase were prepared by radiation-induced graft polymerization of an epoxy-group-containing monomer, glycidyl methacrylate, onto a porous hollow-fiber membrane, and subsequent ring-opening with EA and Ph, respectively. An α-amylase solution was forced to permeate radially outward through the pores of the EA and Ph fibers. α-Amylase was captured at a density of 0.15 and 6.6 g/L of the membrane by the graft chain containing 2-hydroxyethylamino and phenyl groups, respectively. A permeation pressure of 0.10 MPa provided a space velocity of 780 and 1500 h-1 for the α-amylase-immobilized EA and Ph fibers, respectively. Quantitative hydrolysis of starch during permeation of a 20 g/L starch solution in the buffer across the α-amylase-immobilized Ph fiber was attained up to a space velocity of about 2000 h-1; this was achieved because of negligible diffusional mass-transfer resistance of the starch to the α-amylase due to convective flow/ whereas an enzyme reaction-controlled system was observed for the α-amylase-immobilized EA fiber.

  4. Carbon Nanotube/Alumina/Polyethersulfone Hybrid Hollow Fiber Membranes with Enhanced Mechanical and Anti-Fouling Properties

    Directory of Open Access Journals (Sweden)

    Yi Feng

    2015-08-01

    Full Text Available Carbon nanotubes (CNTs were incorporated into alumina/polyethersulfone hollow fibre membranes to enhance the mechanical property and the efficiency of water treatment. Results show that the incorporation of CNTs can greatly limit the formation of large surface pores, decrease the void size in support layers and improve the porosity and pore connectivity of alumina/polyethersulfone membranes. As a result of such morphology change and pore size change, both improved flux and rejection were achieved in such CNTs/alumina/polyethersulfone membranes. Moreover, the CNTs/alumina/PES membranes show higher antifouling ability and the flux recoveries after being fouled by bovine serum albumin (BSA and humic acid were improved by 84.1% and 53.2% compared to the samples without CNT incorporation. Besides the improvement in water treatment performance, the incorporation of CNTs enhanced the tensile properties of inorganic/polymer membranes. Therefore, such CNTs/alumina/PES hollow fiber membranes are very promising candidates for good filter media in industry, considering their high efficiency and high mechanical properties.

  5. Filtering Surface Water with a Polyurethane-based Hollow Fiber Membrane:Effects of Operating Pressure on Membrane Fouling

    Institute of Scientific and Technical Information of China (English)

    赵学辉; 张宏伟; 王捷

    2014-01-01

    Membrane fouling seriously restricts applications of membrane technology. A novel strategy was ap-plied in this study to retard membrane fouling by changing operating pressure with the pressure responsibility membrane. A polyurethane-based hollow fiber membrane was used to treat surface water for evaluating the effect of operating pressure on membrane fouling. Some bench-scale tests in dead-end mode were carried out. In the experi-ments without backwashing, as operating pressure increased, severe membrane fouling occurred on membrane sur-face, while the permeate quality was improved obviously, which is considered to be due to shrinkage deformation. The total resistance, irreversible resistance and reversible resistance under different backwash pressures were de-termined in filtration/backwashing test. With the increase of backwash pressure, the total resistance decreased, and more importantly, the irreversible resistance also decreased, which implies that small particles deposited inside membrane pores and cake layers on membrane surface are effectively removed. Similar results could be obtained in mass balance tests. The results of the present study indicate that the application of pressure responsibility membrane in surface water treatment may be an effective strategy for reducing membrane fouling.

  6. Gypsum (CaSO42H2O) scaling on polybenzimidazole and cellulose acetate hollow fiber membranes under forward osmosis

    KAUST Repository

    Chen, Si Cong

    2013-11-08

    We have examined the gypsum (CaSO42H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42 14.85 after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. 2013 by the authors; licensee MDPI, Basel, Switzerland.

  7. Sensitivity of Hollow Fiber Spacesuit Water Membrane Evaporator Systems to Potable Water Constituents, Contaminants and Air Bubbles

    Science.gov (United States)

    Bue, Grant C.; Trevino, Luis A.; Fritts, Sharon; Tsioulos, Gus

    2008-01-01

    The Spacesuit Water Membrane Evaporator (SWME) is the baseline heat rejection technology selected for development for the Constellation lunar suit. The first SWME prototype, designed, built, and tested at Johnson Space Center in 1999 used a Teflon hydrophobic porous membrane sheet shaped into an annulus to provide cooling to the coolant loop through water evaporation to the vacuum of space. This present study describes the test methodology and planning and compares the test performance of three commercially available hollow fiber materials as alternatives to the sheet membrane prototype for SWME, in particular, a porous hydrophobic polypropylene, and two variants that employ ion exchange through non-porous hydrophilic modified Nafion. Contamination tests will be performed to probe for sensitivities of the candidate SWME elements to ordinary constituents that are expected to be found in the potable water provided by the vehicle, the target feedwater source. Some of the impurities in potable water are volatile, such as the organics, while others, such as the metals and inorganic ions are nonvolatile. The non-volatile constituents will concentrate in the SWME as evaporated water from the loop is replaced by the feedwater. At some point in the SWME mission lifecycle as the concentrations of the non-volatiles increase, the solubility limits of one or more of the constituents may be reached. The resulting presence of precipitate in the coolant water may begin to plug pores and tube channels and affect the SWME performance. Sensitivity to macroparticles, lunar dust simulant, and air bubbles will also be investigated.

  8. Feasibility Study of Advanced NOM-Reduction by Hollow Fiber Ultrafiltration and Nanofiltration at a Swedish Surface Water Treatment Plant

    Directory of Open Access Journals (Sweden)

    Angelica Lidén

    2016-04-01

    Full Text Available Membrane technology, i.e., ultrafiltration and nanofiltration, is growing in popularity, as it is a space efficient alternative for surface water treatment. Two types of hollow fiber membranes were tested in a fully equipped and automated pilot at a Swedish water treatment plant. Raw water was treated by a nanofilter and by coagulation before an ultrafilter. Operation parameters recorded during these trials have been the basis for cost estimations and assessments of environmental impact, comparing the two membrane modules to the existing conventional treatment. The membranes required lower chemical consumption, but led to increased costs from membrane modules and a higher energy demand. Compared to the existing treatment (0.33 €/m3, the operational costs were estimated to increase 6% for ultrafiltration and 30% for nanofiltration. Considering the low emissions from Nordic energy production, the membrane processes would lower the environmental impact, including factors such as climate and ecosystem health. Greenhouse gas emissions would decrease from 161 g CO2-eq/m3 of the existing process, to 127 g CO2-eq/m3 or 83 g CO2-eq/m3 for ultrafiltration and nanofiltration, respectively. Lower chemical consumption and less pollution from the sludge leaving the water treatment plant lead to lower impacts on the environment.

  9. Aminosilane-Grafted Zirconia-Titiania-Silica Nanoparticles/Torlon Hollow Fiber Composites for CO2 Capture.

    Science.gov (United States)

    Rownaghi, Ali A; Kant, Amit; Li, Xin; Thakkar, Harshul; Hajari, Amit; He, Yingxin; Brennan, Patrick J; Hosseini, Hooman; Koros, William J; Rezaei, Fateme

    2016-05-23

    In this work, the development of novel binary and ternary oxide/Torlon hollow fiber composites comprising zirconia, titania, and silica as amine supports was demonstrated. The resulting binary (Zr-Si/PAI-HF, Ti-Si/PAI-HF) and ternary (Zr-Ti-Si/PAI-HF) composites were then functionalized with monoamine-, diamine-, and triamine-substituted trialkoxysilanes and were evaluated in CO2 capture. Although the introduction of both Zr and Ti improved the CO2 adsorption capacity relative to that with Si/PAI-HF sorbents, zirconia was found to have a more favorable effect on the CO2 adsorption performance than titania, as previously demonstrated for amine sorbents in the powder form. The Zr-Ti-Si/PAI-HF sample with an oxide content of 20 wt % was found to exhibit a relatively high CO2 capacity, that is, 1.90 mmol g(-1) at atmospheric pressure under dry conditions, owing to more favorable synergy between the metal oxides and CO2 . The ternary fiber sorbent showed improved sorption kinetics and long-term stability in cyclic adsorption/desorption runs. PMID:27076214

  10. Hollow fiber membrane based H-2 diffusion for efficient in situ biogas upgrading in an anaerobic reactor

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2013-01-01

    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...

  11. Molecularly imprinted polymer-coated hollow fiber membrane for the microextraction of triazines directly from environmental waters.

    Science.gov (United States)

    Barahona, Francisco; Díaz-Álvarez, Myriam; Turiel, Esther; Martín-Esteban, Antonio

    2016-04-15

    In this work, novel molecularly imprinted polymer-coated hollow fibers (MIP-HFs) have been prepared and evaluated for the development of a micro-solid phase extraction method for the analysis of triazines in aqueous samples using high performance liquid chromatography and UV detection. The proposed extraction method combines liquid-liquid microextraction and molecular imprinting technology. In brief, a thin film of toluene is immobilised in the pores of the obtained MIP-HF. Afterwards, the conditioned MIP-HF is immersed in the water sample. Under stirring for a certain time, the target analytes are liquid-liquid extracted from the sample to the immobilised toluene and then these diffuse to the specific binding sites of the MIP. The effect of various experimental parameters as time and stirring-rate and salting-out effect among others, were studied for the establishment of optimum rebinding conditions. Recoveries for seven triazines tested in 100mL pure water samples spiked with 15μgL(-1) of each triazine were within 0.8-6.9%, with a relative standard deviation (RSD)triazine. The proposed methodology was successfully applied to extract the triazines from spiked tap and river water samples at μgL(-1) concentration level. The mircroextraction procedure with the developed MIP-HFs overcomes the typical low performance and lack of selective recognition of MIPs in aqueous media, allowing the determination of triazines in environmental waters at expected real concentration levels. PMID:26994922

  12. Radiosynthesis of hydrogel confined to hollow-fiber membranes for the design of a bioartificial extra-corporeal liver

    Energy Technology Data Exchange (ETDEWEB)

    Hidalgo, R. [Science and Technology Department, Universidad Nacional de Quilmes (Argentina); Vizioli, N. [Analytical Chemistry and Physicochemical Department, Universidad de Buenos Aires (Argentina); Smolko, E.E. [Ezeiza Atomic Centre, CNEA (Argentina); Argibay, P. [ICBME, Hospital Italiano, Buenos Aires (Argentina); Grasselli, M. [Science and Technology Department, Universidad Nacional de Quilmes (Argentina)]. E-mail: mgrasse@unq.edu.ar

    2007-08-15

    Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic permeability and diffusion of glucose, albumin and IgG were measured in these hydrogel-filled membranes. Polyacrylamide 0.5 M showed the best compromise between albumin diffusion (1.2x10{sup -7} cm{sup 2}/s) and HSA/IgG selectivity (2.2)

  13. Radiosynthesis of hydrogel confined to hollow-fiber membranes for the design of a bioartificial extra-corporeal liver

    Science.gov (United States)

    Hidalgo, R.; Vizioli, N.; Smolko, E. E.; Argibay, P.; Grasselli, M.

    2007-08-01

    Current bioartificial extra-corporeal systems are bioreactors where cells are separated from the surrounding media by porous polymeric membranes. The present work focuses on the design of membranes that allow the differential diffusion of plasma metabolites and proteins such as immunoglobulin (IgG). This design will improve catabolites removal and reduce possible immune response and virus infection. We demonstrate the feasibility to synthesize the hydrogels confined to the macroporous structure of membranes by radiation-induced in situ polymerization. The hollow-fiber membranes were soaked in aqueous monomeric solution, rinsed and irradiated while submerged in oil. This procedure confined the hydrogel to the void internal volume of the pores of the membrane. Hydrogels of polyacrylamide and polyHEMA were synthesized this way by irradiation at 10 kGy. Hydraulic permeability and diffusion of glucose, albumin and IgG were measured in these hydrogel-filled membranes. Polyacrylamide 0.5 M showed the best compromise between albumin diffusion (1.2×10 -7 cm 2/s) and HSA/IgG selectivity (2.2).

  14. Application of Hollow Fiber Forward Osmosis Membranes for Produced and Process Water Volume Reduction: An Osmotic Concentration Process.

    Science.gov (United States)

    Minier-Matar, Joel; Santos, Ana; Hussain, Altaf; Janson, Arnold; Wang, Rong; Fane, Anthony G; Adham, Samer

    2016-06-01

    Produced and process water (PPW) from oil and gas operations, specifically in Qatar, are disposed of by deep well injection in onshore facilities. Disposing large volumes of PPW may affect deep well formation sustainability highlighting the need for effective PPW management. Forward osmosis (FO) was applied as an "osmotic concentration" process to reduce PPW injection volumes by 50% using brines and seawater as draw solutions (DS). The energy intensive step of restoring the salinity of the DS was eliminated; the diluted DS would be simply discharged to the ocean. Both hollow fiber and flat sheet FO membranes were tested and the former exhibited better flux and rejection; they are the focus of this study. Optimization experiments, conducted using Box-Behnken statistical design, confirmed that temperature and DS concentration had a substantial effect on performance. To validate the concept, a long-term experiment, under optimized conditions, was conducted with PPW as feed and brine from thermal desalination plant as DS which yielded an average flux of 24 L/m(2)h. The results confirmed that low-energy osmotic concentration FO has the potential for full-scale implementation to reduce PPW injection volumes. Pilot testing opportunities are being evaluated to demonstrate the effectiveness of this technology under field conditions. PMID:27161935

  15. Thermo-responsive poly(N-isopropylacrylamide)-grafted hollow fiber membranes for osteoblasts culture and non-invasive harvest.

    Science.gov (United States)

    Zhuang, Meiling; Liu, Tianqing; Song, Kedong; Ge, Dan; Li, Xiangqin

    2015-10-01

    Hollow fiber membrane (HFM) culture system is one of the most important bioreactors for the large-scale culture and expansion of therapeutic cells. However, enzymatic and mechanical treatments are traditionally applied to harvest the expanded cells from HFMs, which inevitably causes harm to the cells. In this study, thermo-responsive cellulose acetate HFMs for cell culture and non-invasive harvest were prepared for the first time via free radical polymerization in the presence of cerium (IV). ATR-FTIR and elemental analysis results indicated that the poly(N-isopropylacrylamide) (PNIPAAm) was covalently grafted on HFMs successfully. Dynamic contact angle measurements at different temperatures revealed that the magnitude of volume phase transition was decreased with increasing grafted amount of PNIPAAm. And the amount of serum protein adsorbed on HFMs surface also displayed the same pattern. Meanwhile osteoblasts adhered and spread well on the surface of PNIPAAm-grafted HFMs at 37 °C. And Calcein-AM/PI staining, AB assay, ALP activity and OCN protein expression level all showed that PNIPAAm-grafted HFMs had good cell compatibility. After incubation at 20 °C for 120 min, the adhering cells on PNIPAAm-grafted HFMs turned to be round and detached after being gently pipetted. These results suggest that thermo-responsive HFMs are attractive cell culture substrates which enable cell culture, expansion and the recovery without proteolytic enzyme treatment for the application in tissue engineering and regenerative medicine. PMID:26117772

  16. Actual Application of a H2-Based Polyvinyl Chloride Hollow Fiber Membrane Biofilm Reactor to Remove Nitrate from Groundwater

    Directory of Open Access Journals (Sweden)

    Yanhao Zhang

    2015-01-01

    Full Text Available To evaluate the actual performance of the H2-based polyvinyl chloride hollow fiber membrane biofilm reactor (HF-MBfR, we used HF-MBfR to remove nitrate from the nitrate contaminated groundwater with the dissolved oxygen (~6.2 mg/L in Zhangqiu city (Jinan, China. The reactor was operated over 135 days with the actual nitrate contaminated groundwater. The result showed that maximum of nitrate denitrification rate achieved was over 133.8 g NO3--N/m3d (1.18 g NO3--N/m2d and the total nitrogen removal was more than 95.0% at the conditions of influent nitrate 50 mg/L, hydrogen pressure 0.05 MPa, and dissolved oxygen (DO 6.2 mg/L, with the nitrate in effluent under the value limits of drinking water. The fluxes analysis showed that the electron-equivalent fluxes of nitrate, sulfate, and oxygen account for about 81.2%, 15.2%, and 3.6%, respectively, which indicated that nitrate reduction could consume more electrons than that of sulfate reduction and dissolved oxygen reduction. The nitrate reduction was not significantly influenced by sulfate reduction and the dissolved oxygen reduction. Based on the actual groundwater quality on site, the Langelier Saturation Index (LSI was 0.4, and the membrane could be at the risk of surface scaling.

  17. Hollow fiber membrane-coated functionalized polymeric ionic liquid capsules for direct analysis of estrogens in milk samples.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-02-01

    Protein removal process is always time-consuming for the analysis of milk samples. In this work, hollow fiber membrane-coated functionalized polymeric ionic liquid (HF-PIL) capsules were synthesized and used as solid-phase microextraction (SPME) sorbent for direct analysis of estrogens in milk samples. The functionalized PIL monolith sorbent was obtained by copolymerization between 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer and 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL-crosslinking agent. A group of four capsules were installed as SPME device, to determine four kinds of estrogens (estrone, diethylstilbestrol, hexestrol, and 17α-ethynylestradiol) in milk samples, coupled to high performance liquid chromatography. Extraction and desorption conditions were optimized to get satisfactory extraction efficiency. Good linearity was obtained in the range of 5-200 μg L(-1). The limits of detection were 1 μg L(-1) for diethylstilbestrol and 2 μg L(-1) for 17α-ethynylestradiol, estrone, and hexestrol. The present method was applied to analyze the model analytes in different milk samples. Relative recoveries were in the range of 85.5-112%. The HF-PIL SPME capsules showed satisfactory extraction efficiency and high resistance to sample matrix interference. PMID:26753984

  18. Developing a biohybrid lung - sufficient endothelialization of poly-4-methly-1-pentene gas exchange hollow-fiber membranes.

    Science.gov (United States)

    Wiegmann, Bettina; von Seggern, Heide; Höffler, Klaus; Korossis, Sotirios; Dipresa, Daniele; Pflaum, Michael; Schmeckebier, Sabrina; Seume, Jörg; Haverich, Axel

    2016-07-01

    Working towards establishing a biohybrid lung with optimized hemocompatibility, this study analyzed the feasibility of establishing flow-resistant endothelium on heparin/albumin coated poly-4-methly-1-pentene hollow fiber gas exchange membranes (PMP-HFs). The seeding efficiency and proliferation of human cord blood derived endothelial cells (HCBEC) on PMP-HFs were analyzed under static conditions by WST-8 cell proliferation assay and fluorescence microscopy. The HCBEC monolayer integrity under different flow conditions was also assessed. Endothelial-specific phenotype verification, expression activation levels and thrombogenic state markers were quantified by real-time RT-PCR for cell-to-PMP-HF contact under static and dynamic conditions. The results demonstrated the feasibility of establishing a viable, confluent, and flow-resistant endothelial monolayer on the blood-contact surface of PMP-HFs, which maintained a physiological response to TNFα-stimulation and flow conditions. The endothelial phenotype, expression levels of adhesion molecules and thrombogenic state markers were unaffected by cell-to-PMP-HFs contact. These results represent a significant step towards establishing a biohybrid lung. PMID:26919566

  19. Darcy Permeability of Hollow Fiber Membrane Bundles Made from Membrana Polymethylpentene Fibers Used in Respiratory Assist Devices.

    Science.gov (United States)

    Madhani, Shalv P; D'Aloiso, Brandon D; Frankowski, Brian; Federspiel, William J

    2016-01-01

    Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake-Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular, and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A = 497ε - 103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to -3.5% of our prior correlation over the tested porosity range. PMID:26809086

  20. Determination of aromatic amines in environmental water sample by hollow fiber-liquid phase microextraction and microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Lin, Zian; Zhang, Jianhua; Cui, Huimin; Zhang, Lan; Chen, Guonan

    2010-06-25

    A novel method of microemulsion electrokinetic chromatography (MEEKC) coupled with hollow fiber-liquid phase microextraction (HF-LPME) was developed for determination of six aromatic amines including 4-methylaniline, 3-nitroaniline, 2,4-dimethylaniline, 4-chloroaniline, 3,4-dichloraniline and 4-aminobiphenyl. Baseline separation of six aromatic amines was achieved within 8 min by using the microemulsion buffer containing a 10 mM borate buffer at pH 9.0, 0.8% (v/v) ethyl acetate as oil droplets, 60 mM sodium cholate as surfactant, 5.0% (v/v) 1-butanol as co-surfactant. The influence factors relevant to the HF-LPME process were systemically investigated. The obtained enrichment factors were ranged between 70 and 157 in a 30 min extraction time, and the limits of detection ranged between 0.0021 and 0.0048 microg/mL. This purposed method was successfully applied for the analysis of aromatic amines in water sample and the recoveries were ranged from 87.2% to 99.8%. PMID:20478564

  1. Study of enrichment factors for six β-blockers in aliphatic alcohols by hollow-fiber liquid-phase microextraction.

    Science.gov (United States)

    Li, Qing-Lian; Jing, Shao-Jun; Zhang, Jin-Feng; Zhang, Lin; Ran, Cong-Cong; Du, Chao-Hui; Jiang, Ye

    2015-10-01

    The selectivity of a suitable organic solvent is key for extraction in liquid-phase microextraction experiments. Nevertheless, the screening process remains a daunting task. Our research aimed to study the relationship between extraction efficiency and extraction solvents, analytes, and finally select the appropriate extraction solvent. In the present article, β-blockers and six extraction solvents were chosen as the models and hollow-fiber liquid-phase microextraction was conducted. The relationship was built by statistical analysis on the data. Factors affecting extraction efficiency including the logarithms of the octanol/water partition coefficient (logPo/w ) of analytes, acid dissociation constants, the logarithms of the octanol/water partition coefficient of solvents and pH of the sample solution were investigated. The results showed that a low water solubility of extraction solvent is the foundation to ensure higher extraction efficiency. Moreover, when ΔlogPo/w > 0, a higher extraction efficiency is observed at lower ΔlogPo/w , on the contrary, when ΔlogPo/w < 0, extraction efficiency is higher as the absolute value of ΔlogPo/w becomes greater. Finally, the relationship between enrichment factor and extraction solvents, analytes was established and a helpful guidance was provided for the selection of an optimal solvent to obtain the best extraction efficiency by liquid-phase microextraction. PMID:26224511

  2. Enhancement of the flux for polypropylene hollow fiber membrane in a submerged membrane-bioreactor by surface modification

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yin; LEI Hao; XU Zhi-kang

    2006-01-01

    To improve its limiting flux and antifouling characteristics in a submerged membrane-bioreactor (SMBR) for wastewater treatment, polypropylene hollow fiber microporous membrane (PPHFMM) was surface-modified by the plasma-induced immobilization of poly (N-vinyl-2-pyrrolidone) (PVP) and the plasma treatment with different gases respectively. Attenuated total reflection-Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to characterize the structural and morphological changes on the membrane surface. Water contact angle was measured by the sessile drop method. It was found that the water contact angle was 128.8, 72.3, 62.7, 74.4, 79.1,86.3, and 71.3° for the nascent, PVP-immobilized, air,O2, Ar, CO2 and H2O plasma treated PPHFMM, respectively. The SMBR was operated at fixed transmembrane pressure to determine the limiting flux for the PPHFMM before and after surface modification.Results showed that the limiting flux appeared to be 103, 159, 117, 133, 136, 121 and 152 L/(m2·h) for the nascent, PVP-immobilized,air, O2, Ar, CO2 and H2O plasma treated PPHFMM, respectively. After continuous operation for about 50 h in the SMBR, the antifouling characteristics were improved to some extent.

  3. Hybrid bioreactor (HBR) of hollow fiber microfilter membrane and cross-linked laccase aggregates eliminate aromatic pharmaceuticals in wastewaters.

    Science.gov (United States)

    Ba, Sidy; Jones, J Peter; Cabana, Hubert

    2014-09-15

    Widespread detection of numerous micropollutants including aromatic pharmaceuticals in effluents of wastewater treatment plants has prompted much research aimed at efficiently eliminating these contaminants of environmental concerns. In the present work, a novel hybrid bioreactor (HBR) of cross-linked enzymes aggregates of laccase (CLEA-Lac) and polysulfone hollow fiber MF membrane was developed for the elimination of acetaminophen (ACT), mefenamic acid (MFA) and carbamazepine (CBZ) as model aromatic pharmaceuticals. The MF alone showed removals of the three drugs varying approximately from 50 to 90% over the course of 8h in the filtrate of aqueous solution. Synergistic action of the MF and CLEA-Lac during operation achieved eliminations from aqueous solution of around 99%, nearly 100% and up to 85% for ACT, MFA and CBZ, respectively. Under continuous operation, the HBR demonstrated elimination rates of the drugs from filtered wastewater up to 93% after 72h for CBZ and near complete elimination of ACT and MFA was achieved within 24h of treatment. Concomitantly to the drugs eliminations in the wastewater, the CLEA-Lac exhibited 25% residual activity while being continuously recycled with no activity in the filtrate. Meanwhile, the filtrate flowrate showed only minor decline indicating limited fouling of the membrane. PMID:25218263

  4. Fouling behaviors of polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes for engineering osmosis processes

    KAUST Repository

    Chen, Sicong

    2014-02-01

    This paper investigated the individual effects of reverse salt flux and permeate flux on fouling behaviors of as-spun and annealed polybenzimidazole (PBI)-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) hollow fiber membranes under forward osmosis (FO) and pressure retarded osmosis (PRO) processes. Two types of membrane fouling had been studied; namely, inorganic fouling (CaSO4·2H2O gypsum scaling) during FO operations and organic fouling (sodium alginate fouling) during PRO operations. It is found that gypsum scaling on the membrane surface may be inhibited and even eliminated with an increase in reverse MgCl2 flux due to competitive formations of MgSO4° and CaSO4·2H2O. In contrast, the increase of reverse NaCl flux exhibits a slight enhancement on alginate fouling in both FO and PRO processes. Comparing to the reverse salt flux, the permeate flux always plays a dominant role in fouling. Therefore, lesser fouling has been observed on the membrane surface under the pressurized PRO process than FO process because the reduced initial flux mitigates the fouling phenomena more significantly than the enhancement caused by an increase in reverse NaCl flux. © 2013 Elsevier B.V.

  5. Hollow Fiber Membrane Bioreactor Systems for Wastewater Processing: Effects of Environmental Stresses Including Dormancy Cycling and Antibiotic Dosing

    Science.gov (United States)

    Coutts, Janelle L.; Hummerick, Mary E.; Lunn, Griffin M.; Larson, Brian D.; Spencer, LaShelle E.; Kosiba, Michael L.; Khodadad, Christina L.; Catechis, John A.; Birmele, Michele N.; Wheeler, Raymond M.

    2016-01-01

    Membrane-aerated biofilm reactors (MABRs) have been studied for a number of years as an alternate approach for treating wastewater streams during space exploration. While the technology provides a promising pre-treatment for lowering organic carbon and nitrogen content without the need for harsh stabilization chemicals, several challenges must be addressed before adoption of the technology in future missions. One challenge is the transportation of bioreactors containing intact, active biofilms as a means for rapid start-up on the International Space Station or beyond. Similarly, there could be a need for placing these biological systems into a dormant state for extended periods when the system is not in use, along with the ability for rapid restart. Previous studies indicated that there was little influence of storage condition (4 or 25 C, with or without bulk fluid) on recovery of bioreactors with immature biofilms (48 days old), but that an extensive recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy within 4 days (approximately 1 residence). Further dormancy and recovery testing is presented here that examines the role of biofilm age on recovery requirements, repeated dormancy cycle capabilities, and effects of long-duration dormancy cycles (8-9 months) on HFMB systems. Another challenge that must be addressed is the possibility of antibiotics entering the wastewater stream. Currently, for most laboratory tests of biological water processors, donors providing urine may not contribute to the study when taking antibiotics because the effects on the system are yet uncharacterized. A simulated urinary tract infection event, where an opportunistic, pathogenic organism, E. coli, was introduced to the HFMBs followed by dosing with an antibiotic, ciprofloxacin, was completed to study the effect of the antibiotic on reactor performance and to also examine the development of

  6. Simulation of oxygen carrier mediated oxygen transport to C3A hepatoma cells housed within a hollow fiber bioreactor.

    Science.gov (United States)

    Sullivan, Jesse P; Gordon, Jason E; Palmer, Andre F

    2006-02-01

    A priori knowledge of the dissolved oxygen (O2) concentration profile within a hepatic hollow fiber (HF) bioreactor is important in developing an effective bioartificial liver assist device (BLAD). O2 provision is limiting within HF bioreactors and we hypothesize that supplementing a hepatic HF bioreactor's circulating media with bovine red blood cells (bRBCs), which function as an O2 carrier, will improve oxygenation. The dissolved O2 concentration profile within a single HF (lumen, membrane, and representative extra capillary space (ECS)) was modeled with the finite element method, and compared to experimentally measured data obtained on an actual HF bioreactor with the same dimensions housing C3A hepatoma cells. Our results (experimental and modeling) indicate bRBC supplementation of the circulating media leads to an increase in O2 consumed by C3A cells. Under certain experimental conditions (pO2,IN) = 95 mmHg, Q = 8.30 mL/min), the addition of bRBCs at 5% of the average in vivo human red blood cell concentration (% hRBC) results in approximately 50% increase in the O2 consumption rate (OCR). By simply adjusting the operating conditions (pO2,IN) = 25 mmHg, Q = 1.77 mL/min) and increasing bRBC concentration to 25% hRBC the OCR increase is approximately 10-fold. However, the improved O2 concentration profile experienced by the C3A cells could not duplicate the full range of in vivo O2 tensions (25-70 mmHg) typically experienced within the liver sinusoid with this particular HF bioreactor. Nonetheless, we demonstrate that the O2 transport model accurately predicts O2 consumption within a HF bioreactor, thus setting up the modeling framework for improving the design of future hepatic HF bioreactors. PMID:16161160

  7. Periodic harvesting of embryonic stem cells from a hollow-fiber membrane based four-compartment bioreactor.

    Science.gov (United States)

    Knöspel, Fanny; Freyer, Nora; Stecklum, Maria; Gerlach, Jörg C; Zeilinger, Katrin

    2016-01-01

    Different types of stem cells have been investigated for applications in drug screening and toxicity testing. In order to provide sufficient numbers of cells for such in vitro applications a scale-up of stem cell culture is necessary. Bioreactors for dynamic three-dimensional (3D) culture of growing cells offer the option for culturing large amounts of stem cells at high densities in a closed system. We describe a method for periodic harvesting of pluripotent stem cells (PSC) during expansion in a perfused 3D hollow-fiber membrane bioreactor, using mouse embryonic stem cells (mESC) as a model cell line. A number of 100 × 10(6) mESC were seeded in bioreactors in the presence of mouse embryonic fibroblasts (MEF) as feeder cells. Over a cultivation interval of nine days cells were harvested by trypsin perfusion and mechanical agitation every second to third culture day. A mean of 380 × 10(6) mESC could be removed with every harvest. Subsequent to harvesting, cells continued growing in the bioreactor, as determined by increasing glucose consumption and lactate production. Immunocytochemical staining and mRNA expression analysis of markers for pluripotency and the three germ layers showed a similar expression of most markers in the harvested cells and in mESC control cultures. In conclusion, successful expansion and harvesting of viable mESC from bioreactor cultures with preservation of sterility was shown. The present study is the first one showing the feasibility of periodic harvesting of adherent cells from a continuously perfused four-compartment bioreactor including further cultivation of remaining cells. PMID:26486457

  8. Thermo-responsive poly(N-isopropylacrylamide)-grafted hollow fiber membranes for osteoblasts culture and non-invasive harvest

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Meiling, E-mail: zhuangmeiling2006@126.com; Liu, Tianqing, E-mail: liutq@dlut.edu.cn; Song, Kedong, E-mail: kedongsong@dlut.edu.cn; Ge, Dan, E-mail: gedan@dlut.edu.cn; Li, Xiangqin, E-mail: xiangqinli@163.com

    2015-10-01

    Hollow fiber membrane (HFM) culture system is one of the most important bioreactors for the large-scale culture and expansion of therapeutic cells. However, enzymatic and mechanical treatments are traditionally applied to harvest the expanded cells from HFMs, which inevitably causes harm to the cells. In this study, thermo-responsive cellulose acetate HFMs for cell culture and non-invasive harvest were prepared for the first time via free radical polymerization in the presence of cerium (IV). ATR-FTIR and elemental analysis results indicated that the poly(N-isopropylacrylamide) (PNIPAAm) was covalently grafted on HFMs successfully. Dynamic contact angle measurements at different temperatures revealed that the magnitude of volume phase transition was decreased with increasing grafted amount of PNIPAAm. And the amount of serum protein adsorbed on HFMs surface also displayed the same pattern. Meanwhile osteoblasts adhered and spread well on the surface of PNIPAAm-grafted HFMs at 37 °C. And Calcein-AM/PI staining, AB assay, ALP activity and OCN protein expression level all showed that PNIPAAm-grafted HFMs had good cell compatibility. After incubation at 20 °C for 120 min, the adhering cells on PNIPAAm-grafted HFMs turned to be round and detached after being gently pipetted. These results suggest that thermo-responsive HFMs are attractive cell culture substrates which enable cell culture, expansion and the recovery without proteolytic enzyme treatment for the application in tissue engineering and regenerative medicine. - Highlights: • PNIPAAm-grafted HFMs exhibited thermoresponsive characteristic. • The OB cells could adhere and spread well on the surface of PNIPAAm-grafted HFMs. • PNIPAAm-grafted HFMs do not significantly impact ALP activity and OCN protein expression level of OB cells. • Cell could be detached from PNIPAAm-grafted HFMs when temperature decreased from 37 °C to 20 °C.

  9. Thermo-responsive poly(N-isopropylacrylamide)-grafted hollow fiber membranes for osteoblasts culture and non-invasive harvest

    International Nuclear Information System (INIS)

    Hollow fiber membrane (HFM) culture system is one of the most important bioreactors for the large-scale culture and expansion of therapeutic cells. However, enzymatic and mechanical treatments are traditionally applied to harvest the expanded cells from HFMs, which inevitably causes harm to the cells. In this study, thermo-responsive cellulose acetate HFMs for cell culture and non-invasive harvest were prepared for the first time via free radical polymerization in the presence of cerium (IV). ATR-FTIR and elemental analysis results indicated that the poly(N-isopropylacrylamide) (PNIPAAm) was covalently grafted on HFMs successfully. Dynamic contact angle measurements at different temperatures revealed that the magnitude of volume phase transition was decreased with increasing grafted amount of PNIPAAm. And the amount of serum protein adsorbed on HFMs surface also displayed the same pattern. Meanwhile osteoblasts adhered and spread well on the surface of PNIPAAm-grafted HFMs at 37 °C. And Calcein-AM/PI staining, AB assay, ALP activity and OCN protein expression level all showed that PNIPAAm-grafted HFMs had good cell compatibility. After incubation at 20 °C for 120 min, the adhering cells on PNIPAAm-grafted HFMs turned to be round and detached after being gently pipetted. These results suggest that thermo-responsive HFMs are attractive cell culture substrates which enable cell culture, expansion and the recovery without proteolytic enzyme treatment for the application in tissue engineering and regenerative medicine. - Highlights: • PNIPAAm-grafted HFMs exhibited thermoresponsive characteristic. • The OB cells could adhere and spread well on the surface of PNIPAAm-grafted HFMs. • PNIPAAm-grafted HFMs do not significantly impact ALP activity and OCN protein expression level of OB cells. • Cell could be detached from PNIPAAm-grafted HFMs when temperature decreased from 37 °C to 20 °C

  10. Preparation of Sulfobetaine-Grafted PVDF Hollow Fiber Membranes with a Stably Anti-Protein-Fouling Performance

    Directory of Open Access Journals (Sweden)

    Qian Li

    2014-04-01

    Full Text Available Based on a two-step polymerization method, two sulfobetaine-based zwitterionic monomers, including 3-(methacryloylamino propyl-dimethyl-(3-sulfopropyl ammonium hydroxide (MPDSAH and 2-(methacryloyloxyethyl ethyl-dimethyl-(3-sulfopropyl ammonium (MEDSA, were successfully grafted from poly(vinylidene fluoride (PVDF hollow fiber membrane surfaces in the presence of N,N′-methylene bisacrylamide (MBAA as a cross-linking agent. The mechanical properties of the PVDF membrane were improved by the zwitterionic surface layers. The surface hydrophilicity of PVDF membranes was significantly enhanced and the polyMPDSAH-g-PVDF membrane showed a higher hydrophilicity due to the higher grafting amount. Compared to the polyMEDSA-g-PVDF membrane, the polyMPDSAH-g-PVDF membrane showed excellent significantly better anti-protein-fouling performance with a flux recovery ratio (RFR higher than 90% during the cyclic filtration of a bovine serum albumin (BSA solution. The polyMPDSAH-g-PVDF membrane showed an obvious electrolyte-responsive behavior and its protein-fouling-resistance performance was improved further during the filtration of the protein solution with 100 mmol/L of NaCl. After cleaned with a membrane cleaning solution for 16 days, the grafted MPDSAH layer on the PVDF membrane could be maintain without any chang; however, the polyMEDSA-g-PVDF membrane lost the grafted MEDSA layer after this treatment. Therefore, the amide group of sulfobetaine, which contributed significantly to the higher hydrophilicity and stability, was shown to be imperative in modifying the PVDF membrane for a stable anti-protein-fouling performance via the two-step polymerization method.

  11. Strategic Regulatory Evaluation and Endorsement of the Hollow Fiber Tuberculosis System as a Novel Drug Development Tool.

    Science.gov (United States)

    Romero, Klaus; Clay, Robert; Hanna, Debra

    2015-08-15

    The first nonclinical drug development tool (DDT) advanced by the Critical Path to TB Drug Regimens (CPTR) Initiative through a regulatory review process has been endorsed by leading global regulatory authorities. DDTs with demonstrated predictive accuracy for clinical and microbiological outcomes are needed to support decision making. Regulatory endorsement of these DDTs is critical for drug developers, as it promotes confidence in their use in Investigational New Drug and New Drug Application filings. The in vitro hollow fiber system model of tuberculosis (HFS-TB) is able to recapitulate concentration-time profiles (exposure) observed in patients for single drugs and combinations, by evaluating exposure measures for the ability to kill tuberculosis in different physiologic conditions. Monte Carlo simulations make this quantitative output useful to inform susceptibility breakpoints, dosage, and optimal combination regimens in patients, and to design nonclinical experiments in animal models. The Pre-Clinical and Clinical Sciences Working Group within CPTR executed an evidence-based evaluation of the HFS-TB for predictive accuracy. This extensive effort was enabled through the collaboration of subject matter experts representing the pharmaceutical industry, academia, product development partnerships, and regulatory authorities including the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). A comprehensive analysis plan following the regulatory guidance documents for DDT qualification was developed, followed by individual discussions with the FDA and the EMA. The results from the quantitative analyses were submitted to both agencies, pursuing regulatory DDT endorsement. The EMA Qualification Opinion for the HFS-TB DDT was published 26 January 2015 (available at: http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/document_listing/document_listing_000319.jsp). PMID:26224771

  12. Computational evaluation of the thrombogenic potential of a hollow-fiber oxygenator with integrated heat exchanger during extracorporeal circulation.

    Science.gov (United States)

    Pelosi, Alessandra; Sheriff, Jawaad; Stevanella, Marco; Fiore, Gianfranco B; Bluestein, Danny; Redaelli, Alberto

    2014-04-01

    The onset of thromboembolic phenomena in blood oxygenators, even in the presence of adequate anticoagulant strategies, is a relevant concern during extracorporeal circulation (ECC). For this reason, the evaluation of the thrombogenic potential associated with extracorporeal membrane oxygenators should play a critical role into the preclinical design process of these devices. This study extends the use of computational fluid dynamics simulations to guide the hemodynamic design optimization of oxygenators and evaluate their thrombogenic potential during ECC. The computational analysis accounted for both macro- (i.e., vortex formation) and micro-scale (i.e., flow-induced platelet activation) phenomena affecting the performances of a hollow-fiber membrane oxygenator with integrated heat exchanger. A multiscale Lagrangian approach was adopted to infer the trajectory and loading history experienced by platelet-like particles in the entire device and in a repetitive subunit of the fiber bundles. The loading history was incorporated into a damage accumulation model in order to estimate the platelet activation state (PAS) associated with repeated passes of the blood within the device. Our results highlighted the presence of blood stagnation areas in the inlet section that significantly increased the platelet activation levels in particles remaining trapped in this region. The order of magnitude of PAS in the device was the same as the one calculated for the components of the ECC tubing system, chosen as a term of comparison for their extensive diffusion. Interpolating the mean PAS values with respect to the number of passes, we obtained a straightforward prediction of the thrombogenic potential as a function of the duration of ECC. PMID:23053595

  13. Electro-enhanced hollow fiber membrane liquid phase microextraction of Cr(VI) oxoanions in drinking water samples.

    Science.gov (United States)

    Chanthasakda, Nattaporn; Nitiyanontakit, Sira; Varanusupakul, Pakorn

    2016-02-01

    Hollow fiber membrane liquid phase microextraction (HF-LPME) of metal oxoanions was studied using an ionic carrier enhanced by the application of an electric field (electro-enhanced HF-LPME). The Cr(VI) oxoanion was used as the model. The transportation of Cr(VI) oxoanions across the supported liquid membrane (SLM) was explored via the ion-exchange process and electrokinetic migration. The type of SLM, type of acceptor solution, extraction time, electric potential, and stirring rate were investigated and optimized using MilliQ water. Electro-enhanced HF-LPME provided a much higher enrichment factor compared to conventional HF-LPME (no electric potential) for the same extraction time. A mixture of an anion exchange carrier (methyltrialkyl-ammonium chloride, Aliquat 336) in the SLM facilitated the transportation of Cr(VI) oxoanions. The SLM that gave the best performance was 1-heptanol mixed with 5% Aliquat 336 with 1M NaOH as the acceptor. Linearity was obtained in the working range of 3-15 µg L(-1) Cr(VI) (R(2)>0.99) at 30 V with a 5 min extraction time. The limit of detection was below 5 µg L(-1). The relative standard deviation was less than 12%. The method was applied to drinking water samples. The recoveries of spiked Cr(VI) in drinking water samples were in the range of 96-101% based on the matrix-matched calibration curves. The method was limited to samples containing low levels of ions due to the occurrence of electrolysis. The type of SLM, particularly regarding its resistance, should be tuned to control this problematic phenomenon. PMID:26653501

  14. Effects of Additives and Coagulant Temperature on Fabrication of High Performance PVDF/Pluronic F127 Blend Hollow Fiber Membranes via Nonsolvent Induced Phase Separation

    Institute of Scientific and Technical Information of China (English)

    Chun Heng Loh; Rong Wang

    2012-01-01

    Poly(vinylidene fluoride) (PVDF) has become one of the most popular materials for membrane preparation via nonsolvent induced phase separation (NIPS) process. In this study, an amphiphilic block copolymer, Pluronic F127, has been used as both a pore-former and a surface-modifier in the fabrication of PVDF hollow fibermembranes to enhance the membrane permeability and hydrophilicity. The effects of 2nd additive and coagulant temperature on the formation of PVDF/Pluronic F 127 membranes have also been investigated. The as-spun hollow fibers were characterized in terms of cross-sectional morphology, pure water permeation (PWP), relative molecular mass cut-off (MWCO), membrane chemistry, and hydrolphilicity. It was obsered that the addition of Pluronic F 127 significantly increased the PWP of as-spun fibers, while the membrane contact angle was reduced. However, the size of macrovoids in the membranes was undesirably large. The addition of a 2nd additive, including lithium chloride (LiC1) and water, or an increase in coagulant temperature was found to effectively suppress the macrovoid for- mation in the Pluronic-containing membranes. In addition, the use of LiC1 as a 2nd additive also further enhanced the PWP and hydrophilicity of the membranes, while the surface pore size became smaller. PVDF hollow fiber with a PWP as high as 2330 L·m-2·h-1·MPa-1, a MWCO of 53000 and'a contact angle of 71 o was successfully fabricated with 3% (by mass) of Pluronic F127 and 3% (by mass) of LiC1 at a coagulant temperature of 25 ℃, which shows better performance as compared with most of PVDF hollow fiber membranes made by NIPS method.

  15. Olefins-selective asymmetric carbon molecular sieve hollow fiber membranes for hybrid membrane-distillation processes for olefin/paraffin separations

    KAUST Repository

    Xu, Liren

    2012-12-01

    In this paper, the development of asymmetric carbon molecular sieve (CMS) hollow fiber membranes and advanced processes for olefin/paraffin separations based on the CMS membranes are reported. Membrane-based olefin/paraffin separations have been pursued extensively over the past decades. CMS membranes are promising to exceed the performance upper bound of polymer materials and have demonstrated excellent stability for gas separations. Previously, a substructure collapse phenomenon was found in Matrimid ® precursor derived CMS fiber. To overcome the permeance loss due to the increased separation layer thickness, 6FDA-DAM and 6FDA/BPDA-DAM precursors were selected as potential new precursors for carbon membrane formation. Defect-free asymmetric 6FDA-DAM and 6FDA/BPDA-DAM hollow fibers were successfully fabricated from a dry-jet/wet-quench spinning process. Polymer rigidity, glass-rubber transition and asymmetric morphology were correlated. CMS hollow fiber membranes produced from 6FDA-polymer precursors showed significant improvement in permeance for ethylene/ethane and propylene/propane separations. Further studies revealed that the CMS membranes are olefins-selective, which means the membranes are able to effectively separate olefins (ethylene and propylene) from paraffins (ethane and propane). This unique feature of CMS materials enables advanced hybrid membrane-distillation process designs. By using the olefins-selective membranes, these new processes may provide advantages over previously proposed retrofitting concepts. Further applications of the membranes are explored for hydrocarbons processes. Significant energy savings and even reduced footprint may be achieved in olefins production units. © 2012 Elsevier B.V.

  16. Preparation of [11C]-thymidine and [11C]-2'-arabino-2'-fluoro-β-5-methyl-uridine (FMAU) using a hollow fiber membrane bioreactor system

    International Nuclear Information System (INIS)

    A series of hollow fiber membranes containing immobilized enzymes were prepared and used in the synthesis of 11C-labelled nucleosides. 11C-Formaldehyde was produced in an alcohol oxidase/catalase bioreactor and circulated through a thymidylate synthase bioreactor with an appropriate substrate to produce the corresponding 11C-nucleotide. These labellled nucleotides were subsequently dephosphorylated in an alkaline phosphatase bioreactor. The bioreactor approach was amenable to hot-cell conditions and yielded 11C-products in higher yield and shorter synthesis times than conventional chemical approaches. (author)

  17. Prediction of the Pharmacodynamically Linked Variable of Oseltamivir Carboxylate for Influenza A Virus Using an In Vitro Hollow-Fiber Infection Model System▿

    OpenAIRE

    McSharry, James J.; Weng, Qingmei; Brown, Ashley; Kulawy, Robert; Drusano, George L.

    2009-01-01

    MDCK cells transfected with the human β-galactoside α-2,6-sialyltransferase 1 gene (AX-4 cells) were used to determine the drug susceptibility and pharmacodynamically linked variable of oseltamivir for influenza virus. For dose-ranging studies, five hollow-fiber units were charged with 102 A/Sydney/5/97 (H3N2) influenza virus-infected AX-4 cells and 108 uninfected AX-4 cells. Each unit was treated continuously with different oseltamivir carboxylate concentrations in virus growth medium for 6 ...

  18. Clean sub-8-fs pulses at 400 nm generated by a hollow fiber compressor for ultraviolet ultrafast pump-probe spectroscopy.

    Science.gov (United States)

    Liu, Jun; Okamura, Kotaro; Kida, Yuichiro; Teramoto, Takahiro; Kobayashi, Takayoshi

    2010-09-27

    Clean 7.5 fs pulses at 400 nm with less than 3% energy in tiny satellite pulses were obtained by spectral broadening in a hollow fiber and dispersive compensating using a prism pair together with a deformable mirror system. As an example, this stable and clean pulse was used to study the ultrafast pump-probe spectroscopy of photoactive yellow protein. Moreover, the self-diffraction signal shows a smoothed and broadened laser spectrum and is expected to have a further clean laser pulse, which makes it more useful in the ultrafast pump-probe spectroscopy in the future. PMID:20940959

  19. Vacuum ultraviolet argon excimer laser excited by optical-field-induced ionized electrons produced in an argon-filled hollow fiber

    Science.gov (United States)

    Kubodera, Shoichi; Kaku, Masanori; Katto, Masahito

    2011-10-01

    Short-wavelength lasers in the vacuum ultraviolet (VUV) spectral region between 100 and 200 nm have not yet been developed to the same degree as visible and infrared lasers. We have demonstrated the production of argon excimers via an optical-field-induced ionization (OFI) process by using a high-intensity infrared laser. We here report optical amplification of argon excimers at the wavelength of 126 nm by producing an extended OFI plasma inside an argon-filled hollow fiber with an inner diameter of 250 microns with a length of 5.0 cm. A gain-length product of 4.3 through the use of single-pass amplification with VUV optics was observed, indicating a small signal gain coefficient of 0.86 cm-1 with an uncertainty of 0.03. It was found that the hollow fiber served to extend the OFI plasma length and to guide the excitation of the infrared laser and the produced VUV emissions at 126 nm, but did not affect the OFI plasma conditions to produce argon excimer molecules. Short-wavelength lasers in the vacuum ultraviolet (VUV) spectral region between 100 and 200 nm have not yet been developed to the same degree as visible and infrared lasers. We have demonstrated the production of argon excimers via an optical-field-induced ionization (OFI) process by using a high-intensity infrared laser. We here report optical amplification of argon excimers at the wavelength of 126 nm by producing an extended OFI plasma inside an argon-filled hollow fiber with an inner diameter of 250 microns with a length of 5.0 cm. A gain-length product of 4.3 through the use of single-pass amplification with VUV optics was observed, indicating a small signal gain coefficient of 0.86 cm-1 with an uncertainty of 0.03. It was found that the hollow fiber served to extend the OFI plasma length and to guide the excitation of the infrared laser and the produced VUV emissions at 126 nm, but did not affect the OFI plasma conditions to produce argon excimer molecules. Part of this work has been supported by

  20. Nickel(II) removal by mixtures of Acorga M5640 and DP8R in pseudo-emulsion based hollow fiber with strip dispersion technology

    OpenAIRE

    González, Roberto; Cerpa Naranjo, Arisbel; Alguacil, Francisco José

    2010-01-01

    This work presents the investigation of Ni(II) extraction from aqueous solution through pseudo-emulsion based hollow fiber strip dispersion (PSEHFSD) containing the mixture 2-hydroxy-5-nonylbenzaldehyde oxime + di(2-ethylhexyl) phosphoric acid/Exxsol D100 as extractant in the form of a pseudo-emulsion with H2SO4. The organic and aqueous strip phases are separated when the stirring device is stopped. The permeation of Ni(II) is investigated as a function of various experimental var...

  1. The adult brain tissue response to hollow fiber membranes of varying surface architecture with or without cotransplanted cells

    Science.gov (United States)

    Zhang, Ning

    A variety of biomaterials have been chronically implanted into the central nervous system (CNS) for repair or therapeutic purposes. Regardless of the application, chronic implantation of materials into the CNS induces injury and elicits a wound healing response, eventually leading to the formation of a dense extracellular matrix (ECM)-rich scar tissue that is associated with the segregation of implanted materials from the surrounding normal tissue. Often this reaction results in impaired performance of indwelling CNS devices. In order to enhance the performance of biomaterial-based implantable devices in the CNS, this thesis investigated whether adult brain tissue response to implanted biomaterials could be manipulated by changing biomaterial surface properties or further by utilizing the biology of co-transplanted cells. Specifically, the adult rat brain tissue response to chronically implanted poly(acrylonitrile-vinylchloride) (PAN-PVC) hollow fiber membranes (HFMs) of varying surface architecture were examined temporally at 2, 4, and 12 weeks postimplantation. Significant differences were discovered in the brain tissue response to the PAN-PVC HFMs of varying surface architecture at 4 and 12 weeks. To extend this work, whether the soluble factors derived from a co-transplanted cellular component further affect the brain tissue response to an implanted HFM in a significant way was critically exploited. The cells used were astrocytes, whose ability to influence scar formation process following CNS injury by physical contact with the host tissue had been documented in the literature. Data indicated for the first time that astrocyte-derived soluble factors ameliorate the adult brain tissue reactivity toward HFM implants in an age-dependent manner. While immature astrocytes secreted soluble factors that suppressed the brain tissue reactivity around the implants, mature astrocytes secreted factors that enhanced the gliotic response. These findings prove the feasibility

  2. Enhanced fouling by inorganic and organic foulants on pressure retarded osmosis (PRO) hollow fiber membranes under high pressures

    KAUST Repository

    Chen, Sicong

    2015-04-01

    We have studied, for the first time, the fouling behavior of pressure retarded osmosis (PRO) hollow fiber membranes under low, moderate and high hydraulic pressures. The thin film composite (TFC) polyethersulfone (PES) membrane has a high water permeability and good mechanical strength. Membrane fouling by gypsum (CaSO4·2H2O) scalants, sodium alginate, and the combined foulants was examined under various pressures up to an ultrahigh hydraulic pressure of 18bar. In the combined fouling experiments, the membranes were conditioned by one of foulants followed by the other. Flux decline results suggested that such conditioning could increase the rate of combined fouling because of the change in membrane surface chemistry. Specially, the co-existence of gypsum crystals and alginate under 0bar led to the synergistic combined fouling and resulted in a greater flux decline than the sum of individual fouling. Interestingly, such gypsum-alginate synergistic fouling was not observed under high pressure PRO tests because the increased reverse salt flux inhibited the formation of gypsum crystals. Therefore, alginate fouling could be the dominant fouling mechanism for both (1) alginate conditioning and then scalants fouling, and (2) scalants conditioning and then alginate fouling PRO processes under 8bar and 18bar. Since the reverse salt flux increases from 5.6±1.1g/m2h at 0bar to 74.3±9.7g/m2h at 8bar, and finally to 150.5±2.5g/m2h under 18bar, the reverse salt ions lead to substantial declines of normalized flux under 8bar and 18bar because the reverse sodium ions not only reduce the effective driving force across the PRO membrane but also induce a significant cake-enhanced sodium concentration polarization layer and facilitate alginate gelation near the membrane surface. Therefore, the removal of alginate type foulants from the feed water stream may become essential for the success of PRO processes under high pressures.

  3. Freshwater autotrophic picoplankton: a review

    Directory of Open Access Journals (Sweden)

    John G. STOCKNER

    2002-02-01

    Full Text Available Autotrophic picoplankton (APP are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

  4. High-throughput determination of nicotine in plasma by ultrasonication enhanced hollow fiber liquid-phase microextraction prior to gas chromatography.

    Science.gov (United States)

    Liu, Xiaotian; Liang, Shumei; Pan, Jie; Guo, Yugao; Luo, Huiru; Zhao, Qingsong; Guan, Shan

    2014-07-01

    In high-throughput ultrasonication enhanced hollow-fiber liquid-phase microextraction (H-U-HF-LPME), ultrasonication was introduced into HF-LPME to enhance the mass transfer rate of the analytes in the two immiscible liquid phases, which resulted in a very short time for extraction equilibrium and a high-throughput analysis. Several parameters were investigated and optimized (such as extraction solvent, temperature of sample, frequency and intensity of ultrasonication, volume of extractant, extraction time, ionic strength of the sample and sample concentration). Based on the results of this study, nicotine was first extracted from a 1.5 mL sample solution under the optimum conditions (ultrasonic power of 50 W with a frequency of 60 kHz, extraction time of 10 min, sodium chloride concentration of 5 mol/L and temperature of 37°C). Next, 0.5 µL of acceptor solution inside the hollow fiber was automatically injected into a gas chromatograph with a flame ionization detector. The results of this study illustrated that the limit of detection, relative standard deviation (n = 6), relative recovery and enrichment factor of nicotine were 0.06 µg/L, 3%, 99.8% and 16.6, respectively. Finally, H-U-HF-LPME was successfully applied for the determination of nicotine in plasma. PMID:23794719

  5. Analysis of PBDEs in soil, dust, spiked lake water, and human serum samples by hollow fiber-liquid phase microextraction combined with GC-ICP-MS.

    Science.gov (United States)

    Xiao, Qin; Hu, Bin; Duan, Jiankun; He, Man; Zu, Wanqing

    2007-10-01

    A novel method for the analysis of four polybrominated diphenyl ethers (PBDEs) in environmental and human serum samples based on hollow fiber-liquid phase microextraction (HF-LPME) followed by gas chromatography-inductively coupled plasma mass spectrometric (GC-ICP-MS) detection has been developed. The organic solvent in the porous hollow fiber was first dipped into the sample for extraction at a given time, and the retracted organic phase was introduced into the GC-ICP-MS for analysis. The addition of methanol has a strong effect on the HF-LPME extraction efficiency. Other significant parameters affecting the extraction efficiency of HF-LPME were also studied. HF-LPME was effective to isolate the analytes from the complex matrix. Under the optimized conditions, the detection limits of the proposed method varied from 15.2 to 40.5 ng/L. In general, the relative standard deviations (RSDs) were less than 10%. Good linearity was obtained with the correlation coefficients all better than 0.999. The proposed method is simple, quick, few microliters of organic solvent required, and is especially suitable for the analysis of the real sample with small amount available. The overall process of HF-LPME with GC-ICP-MS was applied successfully for the determination of polybrominated diphenyl ethers (PBDEs) in environmental and spiked human serum samples, and the results were satisfactory. PMID:17702599

  6. Hollow fiber-based liquid-liquid-liquid microextraction followed by flow injection analysis using column-less HPLC for the determination of phenazopyridine in plasma and urine.

    Science.gov (United States)

    Saraji, Mohammad; Bidgoli, Ali Akbar Hajialiakbari; Farajmand, Bahman

    2011-07-01

    Hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) followed by flow injection analysis and diode array detection (FIA-DAD) was applied as a simple and sensitive quantitative method for the determination of phenazopyridine in urine and plasma samples. Flow injection system included a conventional HPLC system (without a chromatographic column) and a diode array detector. The extraction of phenazopyridine was carried out using diphenyl ether as the organic phase for filling the pores of the hollow fiber wall, and 0.1 M H(2)SO(4) solution as acceptor phase in the lumen of the fiber. The factors affecting the HF-LLLME and flow injection analysis including type of organic solvent, pH of donor phase, extraction temperature, extraction time, stirring rate, and pH of mobile phase were investigated and the optimal extraction conditions were established. With the consumption of 5 mL of sample solution, the enrichment factor was about 230. The limit of detection was 0.5 μg/L with inter- and intra-day precision being (RSD%) 6.9 and 4.9, respectively. Excellent linearity was found between 5 and 200 μg/L. PMID:21681956

  7. High performance thin-film composite forward osmosis hollow fiber membranes with macrovoid-free and highly porous structure for sustainable water production.

    Science.gov (United States)

    Sukitpaneenit, Panu; Chung, Tai-Shung

    2012-07-01

    The development of high-performance and well-constructed thin-film composite (TFC) hollow fiber membranes for forward osmosis (FO) applications is presented in this study. The newly developed membranes consist of a functional selective polyamide layer formed by highly reproducible interfacial polymerization on a polyethersulfone (PES) hollow fiber support. Using dual-layer coextrusion technology to design and effectively control the phase inversion during membrane formation, the support was designed to possess desirable macrovoid-free and fully sponge-like morphology. Such morphology not only provides excellent membrane strength, but it has been proven to minimize internal concentration polarization in a FO process, thus leading to the water flux enhancement. The fabricated membranes exhibited relatively high water fluxes of 32-34 LMH and up to 57-65 LMH against a pure water feed using 2 M NaCl as the draw solution tested under the FO and pressure retarded osmosis (PRO) modes, respectively, while consistently maintaining relatively low salt leakages below 13 gMH for all cases. With model seawater solution as the feed, the membranes could display a high water flux up to 15-18 LMH, which is comparable to the best value reported for seawater desalination applications. PMID:22663085

  8. Separation of silver nanoparticles by hollow fiber flow field-flow fractionation: Addition of tannic acid into carrier liquid as a modifier.

    Science.gov (United States)

    Saenmuangchin, Rattaporn; Mettakoonpitak, Jaruwan; Shiowatana, Juwadee; Siripinyanond, Atitaya

    2015-10-01

    A homemade hollow fiber flow-field fractionation (Hf-FlFFF) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was set-up for silver nanoparticles (AgNPs) separation by using polysulfone hollow fiber membrane (30,000 MW cutoff) as a separation channel. Tannic acid and citrate stabilized AgNPs were synthesized and introduced into Hf-FlFFF. The effects of carrier liquid and stabilizing agent on retention behavior of AgNPs were investigated. Different elution behaviors were observed as follows: with 0.02% (w/v) FL-70, all of AgNPs were eluted from Hf-FlFFF but differences in retention behaviors were observed for AgNPs with tannic acid and citrate stabilizing agents; and with 30mM TRIS buffer, only tannic acid stabilized AgNPs were eluted from Hf-FlFFF, whereas citrate stabilized AgNPs were not eluted. In this work, tannic acid addition into carrier liquid was proposed to modify the surface of AgNPs and the surface of the membrane, and thereby adjusting the retention behaviors of AgNPs. Various concentrations of tannic acid were added into FL-70 and TRIS buffer. With the use of 0.1mM tannic acid in 30mM TRIS buffer as the carrier liquid, retention behaviors of both tannic acid stabilized- and citrate stabilized-AgNPs were similar and with similar fractionation recovery. PMID:26341593

  9. Staggered-electromagnetophoresis with a Split-flow System for the Separation of Microparticles by a Hollow Fiber-embedded PDMS Microchip.

    Science.gov (United States)

    Iiguni, Yoshinori; Tanaka, Ayaka; Kitagawa, Shinya; Ohtani, Hajime

    2016-01-01

    A novel microchip separation system for microparticles based on electromagnetophoresis (EMP) was developed. In this system, focusing and separation of flowing microparticles in a microchannel could be performed by staggered-EMP by controlling the electric current applied to the channel locally combined with the split-flow system for fractionation of eluates. To apply the electric current through the flushing medium in the microchannel, a hollow fiber-embedded microchip with multiple electrodes was fabricated. The hollow fiber was made by a semi-permeable membrane and could separate small molecules. This microchip allowed us to apply the electric current to a part of the microchannel without any pressure control device because a main channel contacted with the subchannels that had electrodes through the semi-permeable membrane. Moreover, the separation using this microchip was combined with the split-flow system at two outlets to improve separation efficiency. Using this system, with the split-flow ratio of 10:1, 87% of 3 μm polystyrene (PS) latex particles were isolated from a mixture of 3 and 10 μm particles. Even the separation of 6 and 10 μm PS particles was achieved with about 77% recovery and 100% purity. In addition, by controlling the applied current, size fractionation of polypropylene (PP) particles was demonstrated. Moreover, biological particles such as pollens could be separated with high separation efficiency by this technique. PMID:26753704

  10. Analysis of amantadine in biological fluids using hollow fiber-based liquid-liquid-liquid microextraction followed by corona discharge ion mobility spectrometry.

    Science.gov (United States)

    Saraji, Mohammad; Khayamian, Taghi; Mirmahdieh, Shiva; Bidgoli, Ali Akbar Hajialiakbari

    2011-10-15

    A method based on liquid-liquid-liquid microextraction combined with corona discharge ion mobility spectrometry was developed for the analysis of amantadine in human urine and plasma samples. Amantadine was extracted from alkaline aqueous sample as donor phase through a thin phase of organic solvent (n-dodecane) filling the pores of the hollow fiber wall and then back extracted into the organic acceptor phase (methanol) located in the lumen of the hollow fiber. All variables affecting the extraction of analyte including acceptor organic solvent type, concentration of NaOH in donor phase, ionic strength of the sample and extraction time were studied. The linear range was 20-1000 and 5-250 ng/mL for plasma and urine, respectively (r(2)≥0.990). The limits of detection were calculated to be 7.2 and 1.6 ng/mL for plasma and urine, respectively. The relative standard deviation was lower than 8.2% for both urine and plasma samples. The enrichment factors were between 45 and 54. The method was successfully applied for the analysis of amantadine in urine and plasma samples. PMID:21956021

  11. A high-flux polyimide hollow fiber membrane to minimize footprint and energy penalty for CO2 recovery from flue gas

    KAUST Repository

    Lively, Ryan P.

    2012-12-01

    Using a process-guided approach, a new 6FDA-based polyimide - 6FDA-DAM:DABA(4:1) - has been developed in the form of hollow fiber membranes for CO 2 recovery from post-combustion flue gas streams. Dense film studies on this polymer reveal a CO 2 permeability of 224 Barrers at 40°C at a CO 2 feed pressure of 10psia. The dense films exhibit an ideal CO 2/N 2 permselectivity of 20 at 40°C, which permits their use in a two-step counter-flow/sweep membrane process. Dry-jet, wet-quench, non-solvent-induced phase inversion spinning was used to create defect-free hollow fibers from 6FDA-DAM:DABA(4:1). Membranes with defect-free skin layers, approximately 415nm thick, were obtained with a pure CO 2 permeance of 520GPU at 30°C and an ideal CO 2/N 2 permselectivity of 24. Mixed gas permeation and wet gas permeation are presented for the fibers. The CO 2 permeance in the fibers was reduced by approximately a factor of 2 in feeds with 80% humidity. As a proof-of-concept path forward to increase CO 2 flux, we incorporated microporous ZIF-8 fillers into 6FDA-DAM:DABA(4:1) dense films. Our 6FDA-DAM:DABA(4:1)/ZIF-8 dense film composites (20wt% ZIF-8) had a CO 2 permeability of 550 Barrers and a CO 2/N 2 selectivity of 19 at 35°C. Good adhesion between the ZIF and the 6FDA-DAM:DABA(4:1) matrix was observed. CO 2 capture costs of $27/ton of CO 2 using the current, "non-optimized" membrane are estimated using a custom counterflow membrane model. Hollow fiber membrane modules were estimated to have order-of-magnitude reductions in system footprint relative to spiral-wound modules, thereby making them attractive in current space-constrained coal-fired power stations. © 2012 Elsevier B.V.

  12. Synergistic action of non-solvent induced phase separation in preparation of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation

    Institute of Scientific and Technical Information of China (English)

    邱运仁; 漆静; 韦玉清

    2014-01-01

    A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral) hollow fiber membrane via thermally induced phase separation (TIPS) has been carried out. The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed, which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation (NIPS), because of the synergistic action of non-solvent induced phase separation at air gap zero. The pore size gradually decreases from outer surface layer to the intermediate layer, but increases gradually from intermediate layer to the inner surface layer. With the increase of air gap distance, the pore size near the outer surface gets smaller and a dense skin layer is formed, and the pore size gradually increases from the outer surface layer to the inner surface layer. Water permeability of the hollow fiber membrane decreases with air gap distance, the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7m3/(m2·s·kPa) as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s, further decreases from 4.52×10-7 to 1.00×10-8m3/(m2·s·kPa) as the air gap increases from 10 to 40 mm. Both the breaking strength and the elongation increase with the increase of air gap distance. The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.

  13. Application of hollow fiber-supported liquid-phase microextraction coupled with HPLC for the determination of guaifenesin enantiomer-protein binding.

    Science.gov (United States)

    Hatami, Mehdi; Farhadi, Khalil

    2012-07-01

    A hollow fiber liquid-phase microextraction technique coupled with high-performance liquid chromatography with fluorescence detection was employed for determination and evaluation of the binding characteristics of drugs to bovine serum albumin (BSA). Enantiomers of guaifenesin (an expectorant drug) were investigated as a model system. After optimization of some influencing parameters on microextraction, the proposed method was used for calculation of the target drug distribution coefficient between n-octanol and the buffer solution as well as study of drug-BSA binding in physiological conditions. The developed method shows a new, improved and simple procedure for determination of free drug concentration in biological fluids and the extent of drug-protein binding. PMID:22102436

  14. Quantitation of platelet loss with indium-111 labeled platelets in a hollow-fiber membrane oxygenator and arterial filter during extracorporeal circulation in a pig model

    International Nuclear Information System (INIS)

    Platelet consumption in a hollow-fiber membrane oxygenator (HFMO) and arterial filter (AF) during cardiopulmonary bypass (CPB) was quantified in five pigs using Indium-111 labeled autologous platelets. Platelet labeling was performed 20-24 hours before CPB. After general endotracheal anesthesia, the pigs were systemically heparinized and were placed on CPB via a median sternotomy. After 3 hours of CPB, radioactivity was quantified with a gamma camera and an ionization chamber. The percent of injected dose (mean ± SD) was 0.79 +/- 0.45 in the HFMO, 2.52 ± 0.93 in AF, 4.3 ± 1.2 in blood loss during CPB. Platelet consumption in HFMO during CPB was lower than in bubble oxygenators (19%) or silicone membrane oxygenators (12%) as observed in previous studies

  15. Radiation-induced graft polymerization and sulfonation of glycidyl methacrylate on to porous hollow-fiber membranes with different pore sizes

    International Nuclear Information System (INIS)

    An epoxy group containing monomer, glycidyl methacrylate, was grafted on to a porous hollow-fiber membrane, made of polyethylene, whose different pore sizes ranged from 0.2 to 0.5 μm. The resulting epoxy group was converted into a sulfonic acid group as a cation-exchange group to capture metal ions. The porous network was retained after grafting and subsequent sulfonation because the poly-GMA chains invaded the polymer matrix. An increase in the SO3H group density of the graft chain decreased the permeability of pure water because the graft chains expanded toward the pore interior due to their mutual electrostatic repulsion. The ion-exchange adsorption of Pb ions during the permeation of a Pb(NO3)2 solution through the pores edged by the cation-exchange graft chains was observed with a negligible diffusional mass-transfer resistance. (author)

  16. Rapid concentration and dialysis of proteins with single hollow fibers: possible applications in analysis of protein secretion by isolated cells and steroid radioimmunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Rommerts, F.F.G.; Clotscher, W.F.; Van der Molen, H.J.

    1977-10-01

    Single hollow fibers were used in specially made cells for fast concentration and dialysis of solutions containing macromolecules. Volumes on the order of 5 ml of diluted protein solutions could be concentrated to 50--100 ..mu..l or less within 7 min with a protein recovery of 60--80%. More than 99% of the molecules with a molecular weight less than 500 could be removed in less than 1 hr. A possible application of the rapid dialysis method for the mechanization of radioimmunoassays is indicated. It was shown that in the radioimmunoassay of steriods the unbound steroids could be removed after incubation with antiserum, within 10 min and without a change in volume.

  17. Direct determination of chlorophenols in water samples through ultrasound-assisted hollow fiber liquid-liquid-liquid microextraction on-line coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Chao, Yu-Ying; Tu, Yi-Ming; Jian, Zhi-Xuan; Wang, Hsaio-Wen; Huang, Yeou-Lih

    2013-01-01

    In this study we on-line coupled hollow fiber liquid-liquid-liquid microextraction (HF-LLLME), assisted by an ultrasonic probe, with high-performance liquid chromatography (HPLC). In this approach, the target analytes - 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 2,6-dichlorophenol (2,6-DCP), and 3,4-dichlorophenol (3,4-DCP) - were extracted into a hollow fiber (HF) supported liquid membrane (SLM) and then back-extracted into the acceptor solution in the lumen of the HF. Next, the acceptor solution was withdrawn on-line into the HPLC sample loop connected to the HF and then injected directly into the HPLC system for analysis. We found that the chlorophenols (CPs) could diffuse quickly through two sequential extraction interfaces - the donor phase - SLM and the SLM - acceptor phase - under the assistance of an ultrasonic probe. Ultrasonication provided effective mixing of the extracted boundary layers with the bulk of the sample and it increased the driving forces for mass transfer, thereby enhancing the extraction kinetics and leading to rapid enrichment of the target analytes. We studied the effects of various parameters on the extraction efficiency, viz. the nature of the SLM and acceptor phase, the compositions of the donor and acceptor phases, the fiber length, the stirring rate, the ion strength, the sample temperature, the sonication conditions, and the perfusion flow rate. This on-line extraction method exhibited linearity (r(2)≥0.998), sensitivity (limits of detection: 0.03-0.05 μg L(-1)), and precision (RSD%≤4.8), allowing the sensitive, simple, and rapid determination of CPs in aqueous solutions and water samples with a sampling time of just 2 min. PMID:23237709

  18. Determination of melamine in soil samples using surfactant-enhanced hollow fiber liquid phase microextraction followed by HPLC–UV using experimental design

    Directory of Open Access Journals (Sweden)

    Ali Sarafraz Yazdi

    2015-11-01

    Full Text Available Surfactant-enhanced hollow fiber liquid phase (SE-HF-LPME microextraction was applied for the extraction of melamine in conjunction with high performance liquid chromatography with UV detection (HPLC–UV. Sodium dodecyl sulfate (SDS was added firstly to the sample solution at pH 1.9 to form hydrophobic ion-pair with protonated melamine. Then the protonated melamine–dodecyl sulfate ion-pair (Mel–DS was extracted from aqueous phase into organic phase immobilized in the pores and lumen of the hollow fiber. After extraction, the analyte-enriched 1-octanol was withdrawn into the syringe and injected into the HPLC. Preliminary, one variable at a time method was applied to select the type of extraction solvent. Then, in screening step, the other variables that may affect the extraction efficiency of the analyte were studied using a fractional factorial design. In the next step, a central composite design was applied for optimization of the significant factors having positive effects on extraction efficiency. The optimum operational conditions included: sample volume, 5 mL; surfactant concentration, 1.5 mM; pH 1.9; stirring rate, 1500 rpm and extraction time, 60 min. Using the optimum conditions, the method was analytically evaluated. The detection limit, relative standard deviation and linear range were 0.005 μg mL−1, 4.0% (3 μg mL−1, n = 5 and 0.01–8 μg mL−1, respectively. The performance of the procedure in extraction of melamine from the soil samples was good according to its relative recoveries in different spiking levels (95–109%.

  19. Autotrophic ammonia oxidation by soil thaumarchaea

    OpenAIRE

    Zhang, Li-Mei; Offre, Pierre R.; He, Ji-Zheng; Verhamme, Daniel T.; Nicol, Graeme W.; Prosser, James I.

    2010-01-01

    Nitrification plays a central role in the global nitrogen cycle and is responsible for significant losses of nitrogen fertilizer, atmospheric pollution by the greenhouse gas nitrous oxide, and nitrate pollution of groundwaters. Ammonia oxidation, the first step in nitrification, was thought to be performed by autotrophic bacteria until the recent discovery of archaeal ammonia oxidizers. Autotrophic archaeal ammonia oxidizers have been cultivated from marine and thermal spring environments, bu...

  20. 中空纤维致密膜基吸收法在CO2脱除中的应用%Application of Nonporous Hollow Fiber Membrane Contactor in CO2 Removal

    Institute of Scientific and Technical Information of China (English)

    姜尚; 孙承贵; 贾静璇; 康国栋; 曹义鸣; 袁权

    2013-01-01

    In order to investigate the application potential of hollow fiber membrane contactors, a commercial nonporous polyimide hollow fiber membrane contactor (φ200) was tested by using tap water and seawater as absorbents to separate the CO2 from the gas mixture of CO2 and N2. The effects of liquid flow rate, liquid pressure, gas flow rate and gas pressure on the removal efficiency and overall mass transfer coefficient of CO2 were investigated. The experimental results indicate that the membrane resistance and liquid film resistance control the mass transfer when tap water and seawater are employed as absorbents. Furthermore, the removal efficiency is enhanced when the liquid/gas flow rate ratio increases. The nonporous hollow fiber contactor could perform a high CO2 removal with efficiency over 70%by optimizing the operation conditions. Finally, a stable operation process was achieved. This smooth mass transfer process indicates that the nonporous hollow fiber membrane eliminates bubbling problem and weeping problem that are frequently encountered in microporous hollow fiber contactor. Therefore, the non-porous hollow fiber contactor used in this experiment has great potential for application as a gas-liquid contactor.%  以商业φ200聚酰亚胺中空纤维致密膜大组件为接触器,淡水和海水为吸收剂,进行了CO2/N2混合气中CO2的脱除实验。考察了气液相压力和流量对CO2脱除率和过程总传质系数的影响。结果显示,液相压力对膜接触器的影响不大,而加大液/气相流量比可以提高CO2的脱除效率,通过控制操作条件可使膜接触器的CO2脱除率在70%以上。实验过程中,气液两相压力可在较宽范围内独立操作,且无鼓泡和漏液现象发生。研究表明中空纤维致密膜基接触器在CO2气体分离领域具有很好的应用潜力和前景。

  1. Modeling of transport of Cs(I) through hollow fiber supported liquid membrane using Calix(4)arene-bis-2,3-naphtho-crown-6 (CNC) as the carrier

    International Nuclear Information System (INIS)

    Transport of cesium through hollow fiber supported liquid membrane by Calix(4)arene-bis-2,3-naphtho-crown-6 (CNC) is studied. About 99% cesium was transported in about 6 hours at tracer level. A simple mathematical model has been developed to simulate the mass transport of Cs(I) from feed phase to strip phase. A good level of match between simulated result and experimentally obtained data was seen. (author)

  2. The effective recovery of praseodymium from mixed rare earths via a hollow fiber supported liquid membrane and its mass transfer related

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted Research highlights: → Maximum percentage of praseodymium extraction at 91.7% from 10% (v/v) bis (2,4,4-trimethylpentyl) phosphinic acid as extractant carrier in multi cycle operation through single HFLSM module. → Mass transfer mechanism of this system was investigated. → The rate-controlling step of this system was the diffusion of praseodymium ions through the film layer between the feed solution and the liquid membrane. → Model prediction of the dimensionless concentrations and separation factors showed promising agreement with the experimental data. - Abstract: The recovery of praseodymium from mixed rare earths via a hollow fiber supported liquid membrane (HFSLM) was examined. Bis(2,4,4-trimethylpentyl) phosphinic acid - known as Cyanex 272 - was used as an extractant carrier. The stripping solution was hydrochloric acid solution. The experiments examined in functions of the concentrations of the carrier in liquid membrane, the (initial) pH's of initial feed solution within the acidic-pH range, the concentrations of hydrochloric acid, the flow rates of feed and stripping solution, and the operation mode of runs through the hollow fiber module. In addition, the influence of circulation of the stripping solution at various numbers of runs through the HFSLM on the outlet concentration of praseodymium ions in the stripping solution was observed. Mass transfer mechanism in the system was investigated. Extraction equilibrium constant (Kex), distribution ratio (D), permeability (P) and mass transfer coefficients were determined. The aqueous-phase mass-transfer coefficient (ki) and organic-phase mass-transfer coefficient (km) were reported to 0.0103 and 0.788 cm s-1, respectively, in which km is much higher than the ki. Thus it suggests the rate-controlling step is the diffusion of praseodymium ions through the film layer between the feed solution and the liquid membrane. Model prediction of the dimensionless concentrations

  3. Mass transfer modeling on the separation of tantalum and niobium from dilute hydrofluoric media through a hollow fiber supported liquid membrane

    International Nuclear Information System (INIS)

    Highlights: → Simultaneous separation of tantalum and niobium from the mixture solution. → An extraction through a hollow fiber supported liquid membrane (HFSLM). → The effect on tantalum removal found from Aliquat 336. → The mathematical model focusing on the extraction side of the liquid membrane system was presented. → The mass transfer coefficients of the aqueous feed (ki) and the organic membrane phase (km) for the system were estimated as 1.19 x 10-5 and 1.39 x 10-7 cm/s, respectively. → Experimental data and theoretical values were found to be in good agreement when the concentration of Aliquat336 in the membrane phase was below 4% (v/v). - Abstract: The separation of a mixture of tantalum and niobium in dilute hydrofluoric media via hollow fiber supported liquid membrane (HFSLM) was examined. Quaternary ammonium salt (Aliquat336) diluted in kerosene was used as a carrier. The various effects on the transport and separation of tantalum and niobium were studied: concentration of hydrofluoric acid in the feed solution, concentration of the carrier (Aliquat336) in the membrane phase, types of stripping solutions (NaClO4, thiourea and HCl) and their concentration. The extraction of tantalum in the membrane phase from 0.3 M hydrofluoric acid (HF) by 3% (v/v) Aliquat336 was achieved by leaving niobium in the feed solution. Quantitative recovery of tantalum was achieved by 0.2 M NaClO4. Furthermore, a mathematical model focusing on the extraction side of the liquid membrane system was presented in order to predict the concentration of tantalum at different times. The mass transfer coefficients of the aqueous feed (ki) and the organic membrane phase (km) were estimated as 1.19 x 10-5 and 1.39 x 10-7 cm/s, respectively. Therefore, the mass transfer limiting step is the diffusion of tantalum-Aliquat336 through the liquid membrane. Moreover, mass transfer modeling was performed and the validity of the developed model evaluated. Experimental data and

  4. Determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline by inductively coupled plasma mass spectrometry after sample clean up with hollow fiber solid phase microextraction system

    International Nuclear Information System (INIS)

    This study reports a simple and efficient method for the determination of trace Cd, Cu, Fe, Pb and Zn in diesel and gasoline samples by inductively coupled plasma mass spectrometry after matrix removal and analyte pre-concentration using hollow fiber-solid phase microextraction (HF–SPME). The optimization of HF-SPME procedure was carried out using two-level full factorial and central composite designs. Four factors (variables), that are, sample solution pH, acceptor phase amount, extraction time and eluent concentration were optimized. Under the optimized experimental conditions, the precision was ≤ 3% (C = 10 μg L−1, n = 15), limits of detection and quantification ranged from 0.1 to 0.3 μg L−1 and 0.3–0.9 μg L−1, respectively, and the maximum preconcentration factor was 30. The HF-SPME method was applied for the determination of trace metals in real gasoline and diesel samples. - Highlights: • Hollow fiber solid phase microextraction of metal ions in diesel and gasoline • Use of hollow fiber-supported sol–gel combined with cation exchange resin • Optimization of HF-SPME using multivariate techniques • Determination of Cd, Cu, Fe, Pb and Zn using ICP–MS • Relatively low LOD and LOQ

  5. Hollow Fiber Membrane Contactors for CO2 Capture: Modeling and Up-Scaling to CO2 Capture for an 800 MWe Coal Power Station

    Directory of Open Access Journals (Sweden)

    Kimball Erin

    2014-11-01

    Full Text Available A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM with the more conventional structured packing columns as the absorber in amine-based CO2 capture systems for power plants. In order to simulate the operation of industrial scale HFMM systems, a two-dimensional model was developed and validated based on results of a laboratory scale HFMM. After successful experiments and validation of the model, a pilot scale HFMM was constructed and simulated with the same model. The results of the simulations, from both sizes of HFMM, were used to assess the feasibility of further up-scaling to a HFMM system to capture the CO2 from an 800 MWe power plant. The system requirements – membrane fiber length, total contact surface area, and module volume – were determined from simulations and used for an economic comparison with structured packing columns. Results showed that a significant cost reduction of at least 50% is required to make HFMM competitive with structured packing columns. Several factors for the design of industrial scale HFMM require further investigation, such as the optimal aspect ratio (module length/diameter, membrane lifetime, and casing material and shape, in addition to the need to reduce the overall cost. However, HFMM were also shown to have the advantages of having a higher contact surface area per unit volume and modular scale-up, key factors for applications requiring limited footprints or flexibility in configuration.

  6. Comparison between solid phase microextraction (SPME) and hollow fiber liquid phase microextraction (HFLPME) for determination of extractables from post-consumer recycled PET into food simulants.

    Science.gov (United States)

    Oliveira, Éder Costa; Echegoyen, Yolanda; Cruz, Sandra Andrea; Nerin, Cristina

    2014-09-01

    Hollow fiber liquid phase microextraction (HFLPME) and solid phase microextraction (SPME) methods for pre-concentration of contaminants (toluene, benzophenone, tetracosane and chloroform) in food simulants were investigated. For HFLPME 1-heptanol, 2-octanone and dibutyl-ether were studied as extracting solvents. Analysis by gas chromatography coupled to mass spectrometry (GC-MS), flame ionization (GC-FID) and electron capture detectors (GC-ECD) were carried out. In addition, the methods were employed to evaluate the safety in use of a PET material after the recycling process (comprising washing, extrusion and solid state polymerization (SSP)) through extractability studies of the contaminants using 10% (v/v) ethanol in deionized water and 3% (w/v) acetic acid in deionized water as food simulants in different conditions: 10 days at 40°C and 2h at 70°C. The HFLPME preconcentration method provided increased sensitivity when compared to the SPME method and allowed to analyze concentration levels below 10 µg surrogate per kg food simulant. The results of the extractability studies showed considerable reductions after the extrusion and SSP processes and indicated the compliance with regulations for using recycled PET in contact with food. PMID:24913857

  7. Development a scalable production process for truncated human papillomavirus type-6 L1 protein using WAVE Bioreactor and hollow fiber membrane.

    Science.gov (United States)

    Sun, Bo; Zhao, Dandan; Zhang, Xizhen; Gu, Tiejun; Yu, XiangHui; Sun, Shiyang; Zhao, Xinghong; Wei, Liu; Liu, Dawei; Yan, Hui; Meng, Xiangyu; Kong, Wei; Xu, Fei; Yang, Ping; Jiang, Chunlai

    2016-02-01

    Here, we describe a process for expression, purification, and characterization of truncated human papillomavirus type-6 (HPV-6) L1 virus-like particles (VLPs). The scalable cultivation process in a WAVE Bioreactor at the 10-L scale was optimized to express HPV-6 L1 VLPs using the baculovirus insect expression system. A hollow fiber membrane system was used for the integrated operation, including concentration, diafiltration, extraction, and clarification. The HPV-6 L1 protein was further purified by anion-exchange chromatography and hydrophobic chromatography. The HPV-6 L1 protein could self-assemble into VLPs with a diameter of approximately 50-60 nm after removal of the reductant dithiothreitol (DTT). The final purified HPV-6 L1 VLPs product was characterized to estimate yield and purity, and exceeds the requirements for pharmaceutical-grade VLP vaccine. Immunization of mice demonstrated that the vaccine could elicit high titer neutralizing antibodies in vivo. This study confirms the feasibility of producing pharmaceutical-grade HPV type-6 L1 VLPs on an industrial scale for clinical trials. PMID:26446387

  8. Graphene-Coated Hollow Fiber Membrane as the Cathode in Anaerobic Electrochemical Membrane Bioreactors - Effect of Configuration and Applied Voltage on Performance and Membrane Fouling.

    Science.gov (United States)

    Werner, Craig M; Katuri, Krishna P; Hari, Ananda Rao; Chen, Wei; Lai, Zhiping; Logan, Bruce E; Amy, Gary L; Saikaly, Pascal E

    2016-04-19

    Electrically conductive, graphene-coated, hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 and 0.9 V) using a new rectangular reactor configuration compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 μm for rectangular reactors and 4 μm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than that in the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance. PMID:26691927

  9. Hollow fiber liquid-phase microextraction coupled with gas chromatography-flame ionization detection for the profiling of fatty acids in vegetable oils.

    Science.gov (United States)

    Siang, Gan Hui; Makahleh, Ahmad; Saad, Bahruddin; Lim, Boey Peng

    2010-12-24

    The development of a two phase hollow fiber liquid-phase microextraction technique, followed by gas-chromatography-flame ionization detection (GC-FID) for the profiling of the fatty acids (FAs) (lauric, myristic, palmitic, stearic, palmitoleic, oleic, linoleic, linolenic and arachidic) in vegetable oils is described. Heptadecanoic acid methyl ester was used as the internal standard. The FAs were transesterified to their corresponding methyl esters prior to the extraction. Extraction parameters such as type of extracting solvent, temperature, extraction time, stirring speed and salt addition were studied and optimized. Recommended conditions were extraction solvent, n-tridecane; extraction time, 35 min; extraction temperature, ambient; without addition of salt. Enrichment factors varying from 37 to 115 were achieved. Calibration curves for the nine FAs were well correlated (r(2)>0.994) within the range of 10-5000 μg L(-1). The limit of detection (signal:noise, 3) was 4.73-13.21 ng L(-1). The method was successfully applied to the profiling of the FAs in palm oils (crude, olein, kernel, and carotino cooking oil) and other vegetable oils (soybean, olive, coconut, rice bran and pumpkin). The encouraging enrichments achieved offer an interesting option for the profiling of the minor and major FAs in palm and other vegetable oils. PMID:21081239

  10. Simultaneous speciation and preconcentration of ultra traces of inorganic tellurium and selenium in environmental samples by hollow fiber liquid phase microextraction prior to electrothermal atomic absorption spectroscopy determination

    International Nuclear Information System (INIS)

    A simple and effective speciation and preconcentration method based on hollow fiber liquid phase microextraction (HF-LPME) was developed for simultaneous separation of trace inorganic tellurium and selenium in environmental samples prior to electrothermal atomic absorption spectroscopy (ETAAS) determination. The method involves the selective extraction of the Te (IV) and Se (IV) species by HF-LPME with the use of ammonium pyrrolidinecarbodithioate (APDC) as the chelating agent. The complex compounds were extracted into 10 μL of toluene and the solutions were injected into a graphite furnace for the determination of Te (IV) and Se (IV). To determine the total tellurium and selenium in the samples, first Te (VI) and Se (VI) were reduced to Te (IV) and Se (IV), and then the microextraction method was performed. The experimental parameters of HF-LPME were optimized using a central composite design after a 2n-1 fractional factorial experimental design. Under optimum conditions, enrichment factors of up to 520 and 480 were achieved for Te (IV) and Se (IV), respectively. The detection limits were 4 ng L-1 with 3.5% RSD (n = 5, c = 2.0 μg L-1) for Te (IV) and 5 ng L-1 with 3.1% RSD for Se (IV). The applicability of the developed technique was evaluated by application to spiked, environmental water and soil samples.

  11. Simple and Rapid Hollow Fiber Liquid Phase Microextraction Followed by High Performance Liquid Chromatography Method for Determination of Drug-protein Binding

    Institute of Scientific and Technical Information of China (English)

    XI Guo-chen; HU Shuang; BAI Xiao-hong

    2011-01-01

    A method was established using hollow fiber-liquid phase microextraction(HF-LPME) followed by high performance liquid chromatography(HPLC) to determine the concentration of the free(unbound) drug in the solution of the drug and protein.Measurements of drug-protein binding ratios and free drug concentrations were then analyzed with the Klotz equation to determine the equilibrium binding constant and number of binding sites for drug-protein interaction.The optimized method allows one to perform the efficient extraction and separation of free drug from protein-bound drug,protein,and other interfering substances.This approach was used to characterize the binding of the anticholinergic drugs atropine sulfate and scopolamine hydrobromide to proteins in human plasma and bovine serum albumin(BSA).The results demonstrate the utility of HF-LPME method for measuring free drug concentrations in protein-drug mixtures and determining the protein binding parameters of a pharmacologically important class of drugs.

  12. A cluster randomized controlled trial to reduce childhood diarrhea using hollow fiber water filter and/or hygiene-sanitation educational interventions.

    Science.gov (United States)

    Lindquist, Erik D; George, C M; Perin, Jamie; Neiswender de Calani, Karen J; Norman, W Ray; Davis, Thomas P; Perry, Henry

    2014-07-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15-0.30) for the filter arm and 0.27 (95% CI = 0.22-0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59-0.86). PMID:24865680

  13. A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

    Science.gov (United States)

    Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

    2014-01-01

    Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

  14. Hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction for measurement of ibuprofen and naproxen in hair and waste water samples.

    Science.gov (United States)

    Rezaeifar, Zohreh; Es'haghi, Zarrin; Rounaghi, Gholam Hossein; Chamsaz, Mahmoud

    2016-09-01

    A new design of hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction (HBP/GO -HF-SLPME) coupled with high performance liquid chromatography used for extraction and determination of ibuprofen and naproxen in hair and waste water samples. The graphene oxide first synthesized from graphite powders by using modified Hummers approach. The surface of graphene oxide was modified using hyperbranched polyglycerol, through direct polycondensation with thionyl chloride. The ready nanocomposite later wetted by a few microliter of an organic solvent (1-octanol), and then applied to extract the target analytes in direct immersion sampling mode.After the extraction process, the analytes were desorbed with methanol, and then detected via high performance liquid chromatography (HPLC). The experimental setup is very simple and highly affordable. The main factors influencing extraction such as; feed pH, extraction time, aqueous feed volume, agitation speed, the amount of functionalized graphene oxide and the desorption conditions have been examined in detail. Under the optimized experimental conditions, linearity was observed in the range of 5-30,000ngmL(-1) for ibuprofen and 2-10,000ngmL(-1) for naproxen with correlation coefficients of 0.9968 and 0.9925, respectively. The limits of detection were 2.95ngmL(-1) for ibuprofen and 1.51ngmL(-1) for naproxen. The relative standard deviations (RSDs) were found to be less than 5% (n=5). PMID:27428449

  15. Actinide(3)/lanthanide(3) partitioning using n-Pr-BTP as extractant: extraction kinetics and extraction test in a hollow fiber module

    International Nuclear Information System (INIS)

    2,6-di(5,6-di-propyl-1,2,4-triazine-3-yl)pyridine (n-Pr-BTP), first developed in our laboratory, is a very promising extractant for the effective separation of actinides(III) from lanthanides(III). It is able to extract actinides(III) with usable distribution coefficient from 1-2 molar nitric acid selectively over lanthanides(III). The Am(III)/Eu(III) separation factor is approx. 135. The performance of this extractant is further elucidated by kinetic investigations and a counter-current extraction experiment in a hollow fiber module (HFM). The kinetic investigations were performed in a stirred cell. The fact that extraction rate is independent of stirring speed reveals a slow chemical complexation reaction. The HFM extraction test on americium(III)/fission lanthanides(III) separation showed good hydrodynamic behavior. Depending on aqueous flow rate, which was varied, up to 94% americium could be removed from the feed phase. Lanthanide co-extraction was in the range of 1%. (author)

  16. Graphene-coated hollow fiber membrane as the cathode in anaerobic electrochemical membrane bioreactors – Effect of configuration and applied voltage on performance and membrane fouling

    KAUST Repository

    Werner, Craig

    2015-12-22

    Electrically conductive, graphene-coated hollow-fiber porous membranes were used as cathodes in anaerobic electrochemical membrane bioreactors (AnEMBRs) operated at different applied voltages (0.7 V and 0.9 V) using a new rectangular reactor configuration, compared to a previous tubular design (0.7 V). The onset of biofouling was delayed and minimized in rectangular reactors operated at 0.9 V, compared to those at 0.7 V due to higher rates of hydrogen production. Maximum transmembrane pressures for the rectangular reactor were only 0.10 bar (0.7 V) or 0.05 bar (0.9 V) after 56 days of operation, compared to 0.46 bar (0.7 V) for the tubular reactor after 52 days. The thickness of the membrane biofouling layer was approximately 0.4 µm for rectangular reactors and 4 µm for the tubular reactor. Higher permeate quality (TSS = 0.05 mg/L) was achieved in the rectangular AnEMBR than the tubular AnEMBR (TSS = 17 mg/L), likely due to higher current densities that minimized the accumulation of cells in suspension. These results show that the new rectangular reactor design, which had increased rates of hydrogen production, successfully delayed the onset of cathode biofouling and improved reactor performance.

  17. Isolation and preconcentration of Cd(II) from environmental samples using polypropylene porous membrane in a hollow fiber renewal liquid membrane extraction procedure and determination by FAAS

    International Nuclear Information System (INIS)

    The use of polypropylene porous membrane in a hollow fiber renewal liquid membrane (HFRLM) procedure for determination of Cd(II) in water samples was assessed. Ammonium O,O-diethyl dithiophosphate (DDTP) was used to complex cadmium (II) in an acid medium to obtain a neutral hydrophobic complex. The organic solvent introduced to the sample extracts this complex from the aqueous solution and carries it over the polypropylene membrane porous. The organic solvent is immobilized inside the polypropylene membrane porous, leading to an homogeneous phase. The complex strips the lumen of the membrane where, at higher pH, the complex Cd-DDTP is broken down and Cd(II) is released into the stripping phase. EDTA was used to complex the cadmium (II), helping to trap the analyte in the stripping phase. The optimized variables were: sample pH, DDTP concentration, stripping pH, EDTA concentration, extraction temperature and time, extractor solvent and addition of salt to saturate the sample. The sample volume used was 15 mL and the stripping volume was 165 μL. The analyte enrichment factor was 107, limit of detection 1.5 μg L-1, relative standard deviation 4.0% (15 μg L-1, n = 7) and the working linear range 5-30 μg L-1.

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

    Science.gov (United States)

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

    2014-10-01

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

  19. A novel anaerobic electrochemical membrane bioreactor (AnEMBR) with conductive hollow-fiber membrane for treatment of low-organic strength solutions

    KAUST Repository

    Katuri, Krishna

    2014-11-04

    A new anaerobic treatment system that combined a microbial electrolysis cell (MEC) with membrane filtration using electrically conductive, porous, nickel-based hollow-fiber membranes (Ni-HFMs) was developed to treat low organic strength solution and recover energy in the form of biogas. This new system is called an anaerobic electrochemical membrane bioreactor (AnEMBR). The Ni-HFM served the dual function as the cathode for hydrogen evolution reaction (HER) and the membrane for filtration of the effluent. The AnEMBR system was operated for 70 days with synthetic acetate solution having a chemical oxygen demand (COD) of 320 mg/L. Removal of COD was >95% at all applied voltages tested. Up to 71% of the substrate energy was recovered at an applied voltage of 0.7 V as methane rich biogas (83% CH4; < 1% H2) due to biological conversion of the hydrogen evolved at the cathode to methane. A combination of factors (hydrogen bubble formation, low cathode potential and localized high pH at the cathode surface) contributed to reduced membrane fouling in the AnEMBR compared to the control reactor (open circuit voltage). The net energy required to operate the AnEMBR system at an applied voltage of 0.7 V was significantly less (0.27 kWh/m3) than that typically needed for wastewater treatment using aerobic membrane bioreactors (1-2 kWh/m3).

  20. Nickel (II Preconcentration and Speciation Analysis During Transport from Aqueous Solutions Using a Hollow-fiber Permeation Liquid Membrane (HFPLM Device

    Directory of Open Access Journals (Sweden)

    Jan Åke Jönsson

    2011-08-01

    Full Text Available Nickel (II preconcentration and speciation analysis using a hollow fiber supported liquid membrane (HFSLM device was studied. A counterflow of protons coupled to complexation with formate provided the driving force of the process, while Kelex 100 was employed as carrier. The influence of variables related to module configuration (acceptor pH and carrier concentration and to the sample properties (donor pH on the preconcentration factor, E, was simultaneously studied and optimized using a 3 factor Doehlert matrix response surface methodology. The effect of metal concentration was studied as well. Preconcentration factors as high as 4240 were observed  depending on the values of the different variables. The effects of the presence of inorganic anions (NO2-, SO42-, Cl-, NO3-, CO32-, CN- and dissolved organic matter (DOM in the form of humic acids were additionally considered in order to carry out a speciation analysis study. Nickel preconcentration was observed to be independent of both effects, except when cyanide was present in the donor phase. A characterization of the transport regime was performed through the analysis of the dependence of E on the temperature. E increases with the increase in temperature according to the equation E(K = -8617.3 + 30.5T with an activation energy of 56.7 kJ mol-1 suggesting a kinetic-controlled regime. Sample depletion ranged from 12 to 1.2% depending on the volume of the donor phase (100 to 1000 mL, respectively.

  1. Studies on non dispersive solvent extraction for removal of dissolved di-butyl phosphate (DBP) from aqueous medium using hollow fiber membrane contactor

    International Nuclear Information System (INIS)

    PUREX process is based on the principle of mass transfer by liquid liquid dispersion. Tri-n-butyl phosphate (TBP) is universal extractant for PUREX process which is employed for reprocessing the irradiated nuclear fuels for separation and recovery of fissile and fertile materials. The multi cycle solvent extraction processes encompass continuous extraction and stripping operations that are invariably carried out in pulsed columns. The continuous exposure of organic solvent (TBP) to high acidic and radioactive medium leads to decrease the solvent extraction efficiency as it degraded to different level producing di-butyl phosphate and mono-butyl phosphate in significant quantities. Efficiency of purex process decreases as di-butyl phosphate forms aqueous soluble complexes with uranium. Removal of such dissolved DBP from aqueous medium is of direct interest in reprocessing processes as this would enable to sustain the better efficiency of the process and also control the loss of fissile and fertile materials. The non-dispersive solvent extraction is a configuration of the conventional solvent-extraction process where a microporous membrane separates both the immiscible phases, one of which impregnates the membrane, thus bringing the liquid-liquid interface to one side of the membrane. This study is a preliminary evaluation of microporous hollow fiber membrane modules for the removal of dissolved DBP from acidic medium. The performance of the proposed system can be improved by optimizing controlling parameters of the process for quantitative transport of dissolved DBP from acidic medium in the purex process context

  2. Effect of interactions between Co(2+) and surface goethite layer on the performance of α-FeOOH coated hollow fiber ceramic ultrafiltration membranes.

    Science.gov (United States)

    Zhu, Zhiwen; Zhu, Li; Li, Jianrong; Tang, Jianfeng; Li, Gang; Hsieh, Yi-Kong; Wang, TsingHai; Wang, Chu-Fang

    2016-03-15

    The consideration of water energy nexus inspires the environmental engineering community to pursue a more sustainable strategy in the wastewater treatment. One potential response would be to enhance the performance of the low-pressure driven filtration system. To reach this objective, it is essential to have a better understanding regarding the surface interaction between the target substance and the surface of membrane. In this study, the hollow fiber ceramic membranes were coated with a goethite layer in order to enhance the Co(2+) rejection. Experimental results indicate that higher Co(2+) rejections are always accompanied with the significant reduction in the permeability. Based on the consideration of electroviscous effect, the surface interactions including the induced changes in viscosity, pore radius and Donnan effect in the goethite layer are likely responsible for the pH dependent behaviors in the rejection and permeability. These results could be valuable references to develop the filtration system with high rejection along with acceptable degree of permeability in the future. PMID:26704473

  3. Analysis of the Microbial Community in an Acidic Hollow-Fiber Membrane Biofilm Reactor (Hf-MBfR Used for the Biological Conversion of Carbon Dioxide to Methane.

    Directory of Open Access Journals (Sweden)

    Hyun Chul Shin

    Full Text Available Hydrogenotrophic methanogens can use gaseous substrates, such as H2 and CO2, in CH4 production. H2 gas is used to reduce CO2. We have successfully operated a hollow-fiber membrane biofilm reactor (Hf-MBfR for stable and continuous CH4 production from CO2 and H2. CO2 and H2 were diffused into the culture medium through the membrane without bubble formation in the Hf-MBfR, which was operated at pH 4.5-5.5 over 70 days. Focusing on the presence of hydrogenotrophic methanogens, we analyzed the structure of the microbial community in the reactor. Denaturing gradient gel electrophoresis (DGGE was conducted with bacterial and archaeal 16S rDNA primers. Real-time qPCR was used to track changes in the community composition of methanogens over the course of operation. Finally, the microbial community and its diversity at the time of maximum CH4 production were analyzed by pyrosequencing methods. Genus Methanobacterium, related to hydrogenotrophic methanogens, dominated the microbial community, but acetate consumption by bacteria, such as unclassified Clostridium sp., restricted the development of acetoclastic methanogens in the acidic CH4 production process. The results show that acidic operation of a CH4 production reactor without any pH adjustment inhibited acetogenic growth and enriched the hydrogenotrophic methanogens, decreasing the growth of acetoclastic methanogens.

  4. Hollow Fiber Membrane Contactors for Post-Combustion CO2 Capture: A Scale-Up Study from Laboratory to Pilot Plant

    Directory of Open Access Journals (Sweden)

    Chabanon E.

    2014-11-01

    Full Text Available Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfortunately almost systematically on small, laboratory scale, modules. Given the level of flue gas flow rates which have to be treated for carbon capture applications, a consistent scale-up methodology is obviously needed for a rigorous engineering design. In this study, the possibilities and limitations of scale-up strategies for membrane contactors have been explored and will be discussed. Experiments (CO2 absorption from a gas mixture in a 30%wt MEA aqueous solution have been performed both on mini-modules and at pilot scale (10 m2 membrane contactor module based on PTFE hollow fibers. The results have been modelled utilizing a resistance in series approach. The only adjustable parameter is in fitting the simulations to experimental data is the membrane mass transfer coefficient (km, which logically plays a key role. The difficulties and uncertainties associated with scaleup computations from lab scale to pilot scale modules, with a particular emphasis on the km value, are presented and critically discussed.

  5. Hollow Fiber Membrane Contactors for Post-Combustion CO2 Capture: A Scale-Up Study from Laboratory to Pilot Plant

    International Nuclear Information System (INIS)

    Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfortunately almost systematically on small, laboratory scale, modules. Given the level of flue gas flow rates which have to be treated for carbon capture applications, a consistent scale-up methodology is obviously needed for a rigorous engineering design. In this study, the possibilities and limitations of scale-up strategies for membrane contactors have been explored and will be discussed. Experiments (CO2 absorption from a gas mixture in a 30% wt MEA aqueous solution) have been performed both on mini-modules and at pilot scale (10 m2 membrane contactor module) based on PTFE hollow fibers. The results have been modelled utilizing a resistance in series approach. The only adjustable parameter is in fitting the simulations to experimental data is the membrane mass transfer coefficient (km), which logically plays a key role. The difficulties and uncertainties associated with scale-up computations from lab scale to pilot scale modules, with a particular emphasis on the km value, are presented and critically discussed. (authors)

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

    Science.gov (United States)

    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.

  7. Gypsum (CaSO4·2H2O Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

    Directory of Open Access Journals (Sweden)

    Tai-Shung Chung

    2013-11-01

    Full Text Available We have examined the gypsum (CaSO4·2H2O scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO processes. Three hollow fiber membranes made of (1 cellulose acetate (CA, (2 polybenzimidazole (PBI/polyethersulfone (PES and (3 PBI-polyhedral oligomeric silsesquioxane (POSS/polyacrylonitrile (PAN were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface.

  8. Hollow Fiber Membrane Contactors for CO2 Capture: Modeling and Up-Scaling to CO2 Capture for an 800 MWe Coal Power Station

    International Nuclear Information System (INIS)

    A techno-economic analysis was completed to compare the use of Hollow Fiber Membrane Modules (HFMM) with the more conventional structured packing columns as the absorber in amine-based CO2 capture systems for power plants. In order to simulate the operation of industrial scale HFMM systems, a two-dimensional model was developed and validated based on results of a laboratory scale HFMM. After successful experiments and validation of the model, a pilot scale HFMM was constructed and simulated with the same model. The results of the simulations, from both sizes of HFMM, were used to assess the feasibility of further up-scaling to a HFMM system to capture the CO2 from an 800 MWe power plant. The system requirements - membrane fiber length, total contact surface area, and module volume - were determined from simulations and used for an economic comparison with structured packing columns. Results showed that a significant cost reduction of at least 50% is required to make HFMM competitive with structured packing columns. Several factors for the design of industrial scale HFMM require further investigation, such as the optimal aspect ratio (module length/diameter), membrane lifetime, and casing material and shape, in addition to the need to reduce the overall cost. However, HFMM were also shown to have the advantages of having a higher contact surface area per unit volume and modular scale-up, key factors for applications requiring limited footprints or flexibility in configuration. (authors)

  9. Application of nano TiO2 modified hollow fiber membranes in algal membrane bioreactors for high-density algae cultivation and wastewater polishing.

    Science.gov (United States)

    Hu, Weiming; Yin, Jun; Deng, Baolin; Hu, Zhiqiang

    2015-10-01

    Polyvinylidene fluoride (PVDF) hollow fiber membranes with nano-TiO2 (5% of PVDF by mass, average size = 25 nm) additives were fabricated and applied for high-density algae (Chlorella vulgaris) cultivation. At the average light intensity of 121 μmol/m(2)/s, the algal membrane bioreactors (A-MBR) operated at a hydraulic retention time of 0.5d and an average solids retention time of 25d had an average algae biomass concentration of 2350 ± 74 mg/L (in COD units) and algal biomass production rate of 6.5 ± 0.1g/m(2)/d. The A-MBRs removed an average of 78% of phosphorus from the wastewater at the initial total phosphorus concentrations ranging from 3.5 to 8.6 mg/L. The nano TiO2-embedded membranes had improved surface hydrophilicity with its total resistance about 50% lower than that of the control. This study demonstrated that PVDF/TiO2 nanocomposite membranes had a better antifouling property for high-density algae cultivation and wastewater polishing. PMID:26125613

  10. High-Surface-Area CO2 Sponge: High Performance CO2 Scrubbing Based on Hollow Fiber-Supported Designer Ionic Liquid Sponges

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-09-01

    IMPACCT Project: The team from ORNL and Georgia Tech is developing a new technology that will act like a sponge, integrating a new, alcohol-based ionic liquid into hollow fibers (magnified image, right) to capture CO2 from the exhaust produced by coal-fired power plants. Ionic liquids, or salts that exist in liquid form, are promising materials for carbon capture and storage, but their tendency to thicken when combined with CO2 limits their efficiency and poses a challenge for their development as a cost-effective alternative to current-generation solutions. Adding alcohol to the mix limits this tendency to thicken in the presence of CO2 but can also make the liquid more likely to evaporate, which would add significantly to the cost of CO2 capture. To solve this problem, ORNL is developing new classes of ionic liquids with high capacity for absorbing CO2. ORNL’s sponge would reduce the cost associated with the energy that would need to be diverted from power plants to capture CO2 and release it for storage.

  11. Utilizing a one-dimensional multispecies model to simulate the nutrient reduction and biomass structure in two types of H2-based membrane-aeration biofilm reactors (H2-MBfR): model development and parametric analysis.

    Science.gov (United States)

    Wang, Zuowei; Xia, Siqing; Xu, Xiaoyin; Wang, Chenhui

    2016-02-01

    In this study, a one-dimensional multispecies model (ODMSM) was utilized to simulate NO3 (-)-N and ClO4 (-) reduction performances in two kinds of H2-based membrane-aeration biofilm reactors (H2-MBfR) within different operating conditions (e.g., NO3 (-)-N/ClO4 (-) loading rates, H2 partial pressure, etc.). Before the simulation process, we conducted the sensitivity analysis of some key parameters which would fluctuate in different environmental conditions, then we used the experimental data to calibrate the more sensitive parameters μ1 and μ2 (maximum specific growth rates of denitrification bacteria and perchlorate reduction bacteria) in two H2-MBfRs, and the diversity of the two key parameters' values in two types of reactors may be resulted from the different carbon source fed in the reactors. From the simulation results of six different operating conditions (four in H2-MBfR 1 and two in H2-MBfR 2), the applicability of the model was approved, and the variation of the removal tendency in different operating conditions could be well simulated. Besides, the rationality of operating parameters (H2 partial pressure, etc.) could be judged especially in condition of high nutrients' loading rates. To a certain degree, the model could provide theoretical guidance to determine the operating parameters on some specific conditions in practical application. PMID:26490919

  12. A multiphasic hollow fiber reactor for the whole-cell bioconversion of 2-methyl-1,3-propanediol to (r)-beta-hydroxyisobutyric acid.

    Science.gov (United States)

    León, R; Prazeres, D M; Fernandes, P; Molinari, F; Cabral, J M

    2001-01-01

    This paper describes the bioconversion of 2-methyl-1,3-propanediol to (R)-beta-hydoxyisobutyric acid (HIBA) by Acetobacter ALEI in a hollow fiber membrane bioreaction system arrangement that allows the integration of three liquid phases: the aqueous bioconversion phase, the organic phase consisting of a solution of trioctyl phosphine oxide (TOPO) in isooctane, and the third phase consisting of a basic stripping solution that allows reextraction of HIBA from the organic phase. A comparison of HIBA mass transfer experiments was carried out in the membrane reactor with two and three phases for different pH and TOPO concentrations. The use of the three-phase arrangement allows the extraction of high quantities of HIBA from the aqueous medium (higher than 85%) independently of the pH, whereas in the two-phase system the percentage of HIBA extracted from the aqueous medium was lower, 42% in the best case, and strongly influenced by the pH. The percentage of the extractive agent TOPO in the organic phase influenced on the mass transfer rate in both bi- and triphasic arrangements. By simply integrating the re-extraction phase in the system it was possible to increase the extraction yield by 2-fold, reduce the amount of TOPO by 4-fold, and operate at the more favorable pH 4. A bioconversion experiment was done in these conditions (pH = 4, TOPO = 5%) to confirm the advantages of including the third stripping solution. Fed-batch operation of the triphasic membrane reactor was maintained for more than 20 h, reaching an HIBA concentration in the stripping solution of 29 g L(-)(1). PMID:11386867

  13. Separation and determination of seleno amino acids using gas chromatography hyphenated with inductively coupled plasma mass spectrometry after hollow fiber liquid phase microextraction.

    Science.gov (United States)

    Duan, Jiankun; Hu, Bin

    2009-05-01

    A new derivatization-extraction method for preconcentration of seleno amino acids using hollow fiber liquid phase microextraction (HF-LPME) was developed for the separation and determination of seleno amino acids in biological samples by gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS). Derivatization was performed with ethyl chloroformate (ECF) to improve the volatility of seleno amino acids. Parameters influencing microextraction, including extraction solvent, pH of sample solution, extraction time, stirring speed, and inorganic salt concentration have been investigated. Under the optimal conditions, the limits of detection (LODs) obtained for Se-methyl-selenocysteine (SeMeCys), selenomethionine (SeMet), and selenoethionine (SeEth) were 23, 15, and 11 ng Se l(-1), respectively. The relative standard deviations (RSDs) were 14.6%, 16.4%, and 19.4% for SeMeCys, SeMet, and SeEth (c = 1.0 ng ml(-1), n = 7), respectively, and the RSDs for SeMeCys, SeMet could be improved obviously if SeEth was utilized as the internal standard. The proposed method was applied for the determination of seleno amino acids in extracts of garlic, cabbage, and mushroom samples, and the recoveries for the spiked samples were in the range of 96.8-108% and 93.4-115% with and without the use of SeEth as internal standard. The developed method was also applied to the analysis of SeMet in a certified reference material of SELM-1 yeast and the determined value is in good agreement with the certified value. PMID:19053158

  14. Combination of hollow fiber liquid phase microextraction followed by HPLC-DAD and multivariate curve resolution to determine antibacterial residues in foods of animal origin.

    Science.gov (United States)

    Tajabadi, Fateme; Ghambarian, Mahnaz; Yamini, Yadollah; Yazdanfar, Najmeh

    2016-11-01

    In the present research, a carrier mediated hollow fiber based liquid-phase microextraction approach (HF-LPME) prior to high performance liquid chromatography-diode array detection (HPLC-DAD) was developed for the simultaneous determination of the antibacterial residues of four tetracyclines (TCs) and five quinolones (QNs), which are commonly used as veterinary medicines. In order to obtain high extraction efficiency, the parameters affecting HF-LPME were optimized using a three-factor and three-level Box-Behnken design under response surface methodology. This method was validated according to the recommendations of the Food and Drug Administration (FDA), and, for the first time, successfully applied to a wide range of animal source food samples such as fish, milk, and honey as well as the liver and muscles of lamb and chicken. Analytical performance was determined in terms of linearity, intra- and inter-assay precision, detection and quantification limits, matrix effect, accuracy, and drug stability in real samples. Detection and quantitation limits for the different antibiotics ranged between 0.5-20ngg(-1) and 1.25-40ngg(-1), respectively. Intra and inter-day repeatability, expressed as the relative standard deviation, were in the ranges of 3.4-10.7% and 5.0-11.5%, respectively. The procedure allows good preconcentration factors of 175-700. The results of the validation process proved that the method is suitable for determining TCs and QNs residues in surveillance programs. Finally, the applicability of the proposed method was successfully confirmed by the extraction and determination of nine antibiotics in various animal source food samples. The importance of this methodology relies on the combination of HF-LPME/HPLC-DAD second-order data with multivariate curve resolution-alternative least squares (MCR-ALS) algorithm, which improves the resolution of some overlapped chromatograms and, hence, increases the accuracy and repeatability of drug determination. PMID

  15. Phase transfer hollow fiber liquid phase microextraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of trace heavy metals in environmental and biological samples.

    Science.gov (United States)

    Guo, Xueqin; He, Man; Chen, Beibei; Hu, Bin

    2012-11-15

    A new method of phase transfer hollow fiber liquid phase microextraction (PT-HF-LPME) combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) has been developed for the determination of trace Co, Pd, Cd and Bi in environmental and biological samples. In PT-HF-LPME, an intermediate solvent (1-butanol) was added into the sample solution to ensure the maximum contact area between the target metal ions and the chelating reagent (8-hydroxyquinoline, 8-HQ), which accelerated the formation of 8-HQ-metal complexes and their subsequent extraction by extraction solvent (toluene). The experimental parameters affecting the extraction efficiency of PT-HF-LPME for the target metals were studied by simplex optimization and orthogonal array design (OAD) experiments. Under the optimized conditions, the enrichment factors for Co, Pd, Cd and Bi were 110, 393, 121 and 111-fold, respectively, the limits of detection (LODs, 3σ) ranged from 3.7 to 8.3 ng L(-1). The relative standard deviations (RSDs, c=0.5 ng mL(-1), n=7) were 8.7, 6.2, 12.4 and 12.9% for Co, Pd, Cd and Bi, respectively. To validate the accuracy of the proposed method, two Certified Reference Materials of GSBZ50009-88 Environment Water and GBW09103 Human Urine were analyzed, and the results obtained for Cd were in good agreement with the certified values. Finally, the developed method was successfully applied to the analysis of Co, Pd, Cd and Bi in lake water and human urine samples. PMID:23158357

  16. Application of hollow fiber membrane mediated with titanium dioxide nanowire/reduced graphene oxide nanocomposite in preconcentration of clotrimazole and tylosin.

    Science.gov (United States)

    Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Seyed Dorraji, Mir Saeed

    2015-11-13

    In this paper, TiO2 nanowires and TiO2 nanoparticles have been successfully anchored on graphene oxide (GO) nanosheets by a facile one-step hydrothermal method. The synthesized TiO2 NWs/RGO and TiO2 NPs/RGO nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. After comparatively studying of the as-made nanocomposites, TiO2 NWs/RGO nanocomposite showed the best adsorbing performance and applied as an attractive efficient sorbent reinforced with microporous hollow fiber membrane through the sol-gel technology. In the following, the selected nanocomposite was utilized for simultaneous preconcentration and determination of clotrimazole and tylosin using high performance liquid chromatography (HPLC)-UV detection, respectively. In order to optimize the extraction conditions through affecting parameters (pH, stirring rate, salt addition, extraction time and volume of donor phase), response surface methodology (RSM) was employed as a powerful statistical technique. Under the optimal conditions, the limit of detection (S/N=3) of proposed HFSPME method, was 0.67 μg L(-1) for clotrimazole and 0.91 μg L(-1) for tylosin with good linear ranges of 1.7-8000.0 μg L(-1) and 4.0-6000.0 μg L(-1). The inter-day and intra-day relative standard deviations (RSD%) at 100 μg L(-1) concentration level were in the ranges of 2.10-3.58% for clotrimazole and 3.45-7.80% for tylosin (n=5), respectively. The proposed microextraction device was extended for determination of ultra trace amounts of target analytes in milk and urine samples with satisfactory results. PMID:26477522

  17. Graphitic carbon nitrides modified hollow fiber solid phase microextraction for extraction and determination of uric acid in urine and serum coupled with gas chromatography-mass spectrometry.

    Science.gov (United States)

    Sun, Ying-pei; Chen, Juan; Qi, Huan-yang; Shi, Yan-ping

    2015-11-01

    An elevated uric acid (UA) in urine or serum can affect renal function and blood pressure, which is an indicator of gout, cardiovascular and renal diseases, hypertension, etc. In this work, a new type of mixed matrix membrane (MMM), based on graphitic carbon nitrides (g-CNs) and hollow fiber (HF), was prepared and combined with solid phase microextraction (SPME) mode to determine UA in urine and serum followed by gas chromatography-mass spectrometry (GC/MS). The porous g-CNs were dispersed in ammonia, and then the exfoliated g-CNs nanosheets were held in the pores of HF by capillary forces and sonification. The prepared g-CNs modified HF (g-CNs-HF) was immersed in biofluid directly to extract UA with SPME mode and the solvent-free mode is convenient for further derivatization and analysis. To achieve the highest extraction efficiency (EF), main extraction and derivatization parameters, such as g-CNs-HF immobilizing time, sonification power and time of extraction, derivatization and desorption time, were optimized. Under the optimum extraction conditions, a favorable linearity of UA was obtained in the range 0.1-200μgmL(-1) with correlation coefficients higher than 0.9990, and the average recoveries at three spiked levels of UA in urine and serum ranged from 80.7% to 121.6%, from 84.7% to 101.1%, respectively. The obtained results demonstrated the developed g-CNs-HF-SPME is a simple, rapid, cost-effective, solvent-free method for the analysis of UA in biofluid. PMID:26444336

  18. Speciation Analysis of Labile and Total Silver(I) in Nanosilver Dispersions and Environmental Waters by Hollow Fiber Supported Liquid Membrane Extraction.

    Science.gov (United States)

    Chao, Jing-Bo; Zhou, Xiao-Xia; Shen, Mo-Hai; Tan, Zhi-Qiang; Liu, Rui; Yu, Su-Juan; Wang, Xiao-Wei; Liu, Jing-Fu

    2015-12-15

    Hollow fiber supported liquid membrane (HFSLM) extraction was coupled with ICP-MS for speciation analysis of labile Ag(I) and total Ag(I) in dispersions of silver nanoparticles (AgNPs) and environmental waters. Ag(I) in aqueous samples was extracted into the HFSLM of 5%(m/v) tri-n-octylphosphine oxide in n-undecane, and stripped in the acceptor of 10 mM Na2S2O3 and 1 mM Cu(NO3)2 prepared in 5 mM NaH2PO4-Na2HPO4 buffer (pH 7.5). Negligible depletion and exhaustive extraction were conducted under static and 250 rpm shaking to extract the labile Ag(I) and total Ag(I), respectively. The extraction equilibration was reached in 8 h for both extraction modes. The extraction efficiency and detection limit were (2.97 ± 0.25)% and 0.1 μg/L for labile Ag(I), and (82.3 ± 2.0)% and 0.5 μg/L for total Ag(I) detection, respectively. The proposed method was applied to determine labile Ag(I) and total Ag(I) in different sized AgNP dispersions and real environmental waters, with spiked recoveries of total Ag(I) in the range of 74.0-98.1%. With the capability of distinguishing labile and total Ag(I), our method offers a new approach for evaluating the bioavailability and understanding the fate and toxicity of AgNPs in aquatic systems. PMID:26580982

  19. Hollow fiber liquid phase microextraction combined with electrothermal atomic absorption spectrometry for the speciation of arsenic (III) and arsenic (V) in fresh waters and human hair extracts.

    Science.gov (United States)

    Jiang, Hongmei; Hu, Bin; Chen, Beibei; Xia, Linbo

    2009-02-16

    A new method of hollow fiber liquid phase microextraction (HF-LPME) using ammonium pyrrolidine dithiocarbamate (APDC) as extractant combined with electrothermal atomic absorption spectrometry (ETAAS) using Pd as permanent modifier has been described for the speciation of As(III) and As(V). In a pH range of 3.0-4.0, the complex of As(III)-APDC complex can be extracted using toluene as the extraction solvent leaving As(V) in the aqueous layer. The post extraction organic phase was directly injected into ETAAS for the determination of As(III). To determine total arsenic in the samples, first As(V) was reduced to As(III) by l-cysteine, and then a microextraction method was performed prior to the determination of total arsenic. As(V) assay was based on subtracting As(III) form the total arsenic. All parameters, such as pH of solution, type of organic solvent, the amount of APDC, stirring rate and extraction time, affecting the separation of As(III) from As(V) and the extraction efficiency of As(III) were investigated, and the optimized extraction conditions were established. Under optimized conditions, a detection limit of 0.12ngmL(-1) with enrichment factor of 78 was achieved. The relative standard deviation (R.S.D.) of the method for five replicate determinations of 5ngmL(-1) As(III) was 8%. The developed method was applied to the speciation of As(III) and As(V) in fresh water and human hair extracts, and the recoveries for the spiked samples are 86-109%. In order to validate the developed method, three certified reference materials such as GBW07601 human hair, BW3209 and BW3210 environmental water were analyzed, and the results obtained were in good agreement with the certified values provided. PMID:19154804

  20. Simple hollow fiber renewal liquid membrane extraction method for pre-concentration of Cd(II) in environmental samples and detection by Flame Atomic Absorption Spectrometry

    International Nuclear Information System (INIS)

    A hollow fiber renewal liquid membrane (HFRLM) extraction method to determine cadmium (II) in water samples using Flame Atomic Absorption Spectrometry (FAAS) was developed. Ammonium O,O-diethyl dithiophosphate (DDTP) was used to complex cadmium (II) in an acid medium to obtain a neutral hydrophobic complex (ML2). The organic solvent introduced to the sample extracts this complex from the aqueous solution and carries it over the poly(dimethylsiloxane) (PDMS) membrane, that had their walls previously filled with the same organic solvent. The organic solvent is solubilized inside the PDMS membrane, leading to a homogeneous phase. The complex strips the lumen of the membrane where, at higher pH, the complex Cd-DDTP is broken down and cadmium (II) is released into the stripping phase. EDTA was used to complex the cadmium (II), helping to trap the analyte in the stripping phase. A multivariate procedure was used to optimize the studied variables. The optimized variables were: sample (donor phase) pH 3.25, DDTP concentration 0.05% (m/v), stripping (acceptor phase) pH 8.75, EDTA concentration 1.5 x 10-2 mol L-1, extraction temperature 40 deg. C, extraction time 40 min, a solvent mixture N-butyl acetate and hexane (60/40%, v/v) with a volume of 100 μL, and addition of ammonium sulfate to saturate the sample. The sample volume used was 20 mL and the stripping volume was 165 μL. The analyte enrichment factor was 120, limit of detection (LOD) 1.3 μg L-1, relative standard deviation (RSD) 5.5% and the working linear range 2-30 μg L-1.

  1. Reconstruction of liver tissue in vitro: geometry of characteristic flat bed, hollow fiber, and spouted bed bioreactors with reference to the in vivo liver.

    Science.gov (United States)

    Bader, A; Knop, E; Frühauf, N; Crome, O; Böker, K; Christians, U; Oldhafer, K; Ringe, B; Pichlmayr, R; Sewing, K F

    1995-09-01

    Bioreactors currently being developed for hybrid artificial livers vary greatly with respect to their microenvironment. The specific architecture modifies the relationship parenchymal and nonparenchymal cells have with the exchange surfaces of the bioreactor. Most designs are either based on hollow fiber, spouted bed, or flat bed devices. This diversity is contrasted by the uniform and unique organization of the in vivo liver. The liver cells are arranged as plates and both sinusoidal surfaces of the hepatocytes are enclosed within the matrix of the space of Disse. In this study we intended to define the in vivo liver tissue characteristics in a manner useful for an organotypical approach to hepatic tissue engineering. Transmission electron microscopy of an in vivo liver was utilized to describe these ratios. The ratios defined in this study are based on the constant hepatocellular expression of two sinusoidal surfaces. A relationship is established between the expression of the sinusoidal surfaces and their use as attachment and exchange surfaces inside a bioreactor. The presence of biliary surfaces and nonparenchymal cell surfaces is compared. The functional relevance of an in vivo like extracellular matrix geometry for oxidative biotransformation of primary hepatocytes in vitro was studied using the two model drugs cyclosporin and rapamycin. The generation of the hydroxylated cyclosporin metabolites AM 9 and AM 1 and four rapamycin metabolites was analyzed by high performance liquid chromatography (HPLC). It is shown that the cell-specific biotransformation rates at 1 week in culture in matrix overlayed hepatocytes was 5-10 times that of hepatocytes without matrix overlay. Bilaminar membrane (BLM) bioreactors were used to reconstruct extracellular matrix geometry, three-dimensional cell plates, and sinusoidal analogs in between cell plates. PMID:8687303

  2. Asymmetric Hollow Fiber Membranes for Separation of CO 2 from Hydrocarbons and Fluorocarbons at High-Pressure Conditions Relevant to C 2 F 4 Polymerization

    KAUST Repository

    Kosuri, Madhava R.

    2009-12-02

    Separation of high-pressure carbon dioxide from fluorocarbons is important for the production of fluoropolymers such as poly(tetrafluoroethylene). Typical polymeric membranes plasticize under high CO2 partial pressure conditions and fail to provide adequate selective separations. Torlon, a polyamide-imide polymer, with the ability to form interchain hydrogen bonding, is shown to provide stability against aggressive CO2 plasticization. Torlon membranes in the form of asymmetric hollow fibers (the most productive form of membranes) are considered for an intended separation of CO 2/C2F4. To avoid safety issues with tetrafluoroethylene (C2F4), which could detonate under testing conditions, safer surrogate mixtures (C2H2F 2 and C2H4) are considered in this paper. Permeation measurements (at 35 °C) indicate that the Torlon membranes are not plasticized even up to 1250 psi of CO2. The membranes provide mixed gas CO2/C2H2F2 and CO 2/C2H4 selectivities of 100 and 30, respectively, at 1250 psi partial pressures of CO2. On the basis of the measured separation performances of CO2/C2H 2F2 and CO2/C2H4 mixtures, the selectivity of the CO2/C2F4 mixture is expected to be greater than 100. Long-term stability studies indicate that the membranes provide stable separations over a period of 5 days at 1250 psi partial pressures of CO2, thereby making the membrane approach attractive. © 2009 American Chemical Society.

  3. Research Progress on the Preparation of Ceramic Hollow Fiber Membranes by Nonsolvent Induced Phase Separation%浸渍相转化法制备陶瓷中空纤维膜的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘朋超; 马敬红; 杨曙光; 龚静华; 徐坚

    2012-01-01

    浸渍相转化法可以制备非对称结构的陶瓷中空纤维膜.本文讨论了陶瓷中空纤维膜的发展情况,并着重探讨了各因素对膜孔结构的影响.大量陶瓷粉体存在情况下的相转化机理,孔结构与力学强度的平衡问题,是目前需要重点关注的两个问题.有效调节孔结构,保证其力学性能可以实现陶瓷中空纤维膜在分离和纯化、固体氧化物燃料电池、膜催化器和膜反应器等方面的广泛应用.%Ceramic hollow fiber membranes (CHFM) with an asymmetric structure can be fabricated by the method nonsolvent induced phase separation (NIPS). The paper reviews the progress and tendency of the ceramic hollow fiber membranes using NIPS technic, especially on the influence of factors on the structure of hollow membranes. The discussion on the mechanism of phase inversion in the systems containing much ceramic powders, with the balance between porous structure and mechanical strength, are two important issues of requiring concern. Through structure's controlled effectively and mechanical strength preserved, hollow fiber membranes can be widely applied in the fields of separation and purification, solid oxide fuel cell (SOFC), membrane contactors and reactors.

  4. Glycine functionalized multiwall carbon nanotubes as a novel hollow fiber solid-phase microextraction sorbent for pre-concentration of venlafaxine and o-desmethylvenlafaxine in biological and water samples prior to determination by high-performance liquid chromatography.

    Science.gov (United States)

    Ghorbani, Mahdi; Chamsaz, Mahmoud; Rounaghi, Gholam Hossein

    2016-06-01

    A hollow fiber solid-phase microextraction method for pre-concentration of venlafaxine and o-desmethylvenlafaxine in biological matrices is described for the first time. The functionalized MWCNTs with an amino acid, glycine, were synthesized and held in the pore of a hollow fiber by sol-gel technique. In order to extract venlafaxine and o-desmethylvenlafaxine from real samples, the hollow fiber was immersed into the sample solution under a magnetic stirring for 20 min. The extracted venlafaxine and o-desmethylvenlafaxine from the fibers were then desorbed with methanol by sonication and analyzed using high-performance liquid chromatography. Important microextraction parameters including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. The optimized technique provides good repeatability (RSD of the intraday precision 3.7 and 3.4, interday precision of 5.8 and 5.4 %), linearity of (0.1-300 and 0.2-360 ng mL(-1)), low LODs of (0.03 and 0.07 ng mL(-1)), and high enrichment factor of (164 and 176) for venlafaxine and o-desmethylvenlafaxine, respectively. The analytical performance of Gly-MWCNTs as a new SPME sorbent was compared with MWCNTs and carboxylic MWCNTs. The results indicate that Gly-MWCNTs are quite effective for extraction of venlafaxine and o-desmethylvenlafaxine. Feasibility of the method was evaluated by analyzing human urine and real water samples. The results obtained in this work show a promising, simple, selective, and sensitive sample preparation and determination method for biological and water samples. PMID:27108286

  5. A modified EPA Method 1623 that uses tangential flow hollow-fiber ultrafiltration and heat dissociation steps to detect waterborne Cryptosporidium and Giardia spp.

    Science.gov (United States)

    Rhodes, Eric R; Villegas, Leah Fohl; Shaw, Nancy J; Miller, Carrie; Villegas, Eric N

    2012-01-01

    Cryptosporidium and Giardia species are two of the most prevalent protozoa that cause waterborne diarrheal disease outbreaks worldwide. To better characterize the prevalence of these pathogens, EPA Method 1623 was developed and used to monitor levels of these organisms in US drinking water supplies (12). The method has three main parts; the first is the sample concentration in which at least 10 L of raw surface water is filtered. The organisms and trapped debris are then eluted from the filter and centrifuged to further concentrate the sample. The second part of the method uses an immunomagnetic separation procedure where the concentrated water sample is applied to immunomagnetic beads that specifically bind to the Cryptosporidium oocysts and Giardia cysts allowing for specific removal of the parasites from the concentrated debris. These (oo)cysts are then detached from the magnetic beads by an acid dissociation procedure. The final part of the method is the immunofluorescence staining and enumeration where (oo)cysts are applied to a slide, stained, and enumerated by microscopy. Method 1623 has four listed sample concentration systems to capture Cryptosporidium oocysts and Giardia cysts in water: Envirochek filters (Pall Corporation, Ann Arbor, MI), Envirochek HV filters (Pall Corporation), Filta-Max filters (IDEXX, Westbrook, MA), or Continuous Flow Centrifugation (Haemonetics, Braintree, MA). However, Cryptosporidium and Giardia (oo)cyst recoveries have varied greatly depending on the source water matrix and filters used(1,14). A new tangential flow hollow-fiber ultrafiltration (HFUF) system has recently been shown to be more efficient and more robust at recovering Cryptosporidium oocysts and Giardia cysts from various water matrices; moreover, it is less expensive than other capsule filter options and can concentrate multiple pathogens simultaneously(1-3,5-8,10,11). In addition, previous studies by Hill and colleagues demonstrated that the HFUF significantly

  6. Removal of transmissible spongiform encephalopathy prion from large volumes of cell culture media supplemented with fetal bovine serum by using hollow fiber anion-exchange membrane chromatography.

    Directory of Open Access Journals (Sweden)

    Ming Li Chou

    Full Text Available Cases of variant Creutzfeldt-Jakob disease in people who had consumed contaminated meat products from cattle with bovine spongiform encephalopathy emphasize the need for measures aimed at preventing the transmission of the pathogenic prion protein (PrPSc from materials derived from cattle. Highly stringent scrutiny is required for fetal bovine serum (FBS, a growth-medium supplement used in the production of parenteral vaccines and therapeutic recombinant proteins and in the ex vivo expansion of stem cells for transplantation. One such approach is the implementation of manufacturing steps dedicated to removing PrPSc from materials containing FBS. We evaluated the use of the QyuSpeed D (QSD adsorbent hollow-fiber anion-exchange chromatographic column (Asahi Kasei Medical, Tokyo, Japan for the removal of PrPSc from cell culture media supplemented with FBS. We first established that QSD filtration had no adverse effect on the chemical composition of various types of culture media supplemented with 10% FBS or the growth and viability characteristics of human embryonic kidney (HEK293 cells, baby hamster kidney (BHK-21 cells, African green monkey kidney (Vero cells, and Chinese hamster ovary (CHO-k1 cells propagated in the various culture-medium filtrates. We used a 0.6-mL QSD column for removing PrPSc from up to 1000 mL of Dulbecco's modified Eagle's medium containing 10% FBS previously spiked with the 263K strain of hamster-adapted scrapie. The Western blot analysis, validated alongside an infectivity assay, revealed that the level of PrPSc in the initial 200mL flow-through was reduced by 2.5 to > 3 log10, compared with that of the starting material. These results indicate that QSD filtration removes PrPSc from cell culture media containing 10% FBS, and demonstrate the ease with which QSD filtration can be implemented in at industrial-scale to improve the safety of vaccines, therapeutic recombinant proteins, and ex vivo expanded stem cells produced

  7. Mathematic Model of Unsteady Penetration Mass Transfer in Randomly Packed Hollow Fiber Membrane Module%随机填充中空纤维膜组件中非稳态渗透传质数学模型

    Institute of Scientific and Technical Information of China (English)

    张秀莉; 张泽廷; 张卫东; 郝欣

    2004-01-01

    Based on the membrane-based absorption experiment of C02 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data.

  8. Clostridium difficile is an autotrophic bacterial pathogen.

    Directory of Open Access Journals (Sweden)

    Michael Köpke

    Full Text Available During the last decade, Clostridium difficile infection showed a dramatic increase in incidence and virulence in the Northern hemisphere. This incessantly challenging disease is the leading cause of antibiotic-associated and nosocomial infectious diarrhea and became life-threatening especially among elderly people. It is generally assumed that all human bacterial pathogens are heterotrophic organisms, being either saccharolytic or proteolytic. So far, this has not been questioned as colonization of the human gut gives access to an environment, rich in organic nutrients. Here, we present data that C. difficile (both clinical and rumen isolates is also able to grow on CO2+H2 as sole carbon and energy source, thus representing the first identified autotrophic bacterial pathogen. Comparison of several different strains revealed high conservation of genes for autotrophic growth and showed that the ability to use gas mixtures for growth decreases or is lost upon prolonged culturing under heterotrophic conditions. The metabolic flexibility of C. difficile (heterotrophic growth on various substrates as well as autotrophy could allow the organism in the gut to avoid competition by niche differentiation and contribute to its survival when stressed or in unfavorable conditions that cause death to other bacteria. This may be an important trait for the pathogenicity of C. difficile.

  9. Simultaneous speciation and preconcentration of ultra trace concentrations of mercury and selenium species in environmental and biological samples by hollow fiber liquid phase microextraction prior to high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Moreno, F; García-Barrera, T; Gómez-Ariza, J L

    2013-07-26

    Nowadays, hollow fiber membrane extraction techniques are widely used due to the high enrichment factors obtained with many different types of analytes and samples. In this paper, we propose a new analytical method that allows the simultaneous extraction of methylmercury, inorganic mercury and Se(4+) and determination by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The detection limits obtained are very low (110-230ng/L) with relative standard deviations below 15% for all the analytes and averaged recoveries in fortified samples in the range of 71-99%. The precision of the analytical method is very good which overcomes one of the most important shortcomings of membrane extraction techniques. Several variables were studied to get optimal extraction conditions for the analytes. This method has been validated with real world samples such as water (tap, river and estuarine) and human blood plasma. PMID:23541655

  10. Evaluation of the measurement of Cu(II) bioavailability in complex aqueous media using a hollow-fiber supported liquid membrane device (HFSLM) and two microalgae species (Pseudokirchneriella subcapitata and Scenedesmus acutus).

    Science.gov (United States)

    Rodríguez-Morales, Erik A; Rodríguez de San Miguel, Eduardo; de Gyves, Josefina

    2015-11-01

    The environmental bioavailability of copper was determined using a hollow-fiber supported liquid membrane (HFSLM) device as a chemical surrogate and two microalgae species (Scenedesmus acutus and Pseudokirchneriella subcapitata). Several experimental conditions were studied: pH, the presence of organic matter, inorganic anions, and concomitant cations. The results indicated a strong relationship between the response given by the HFSLM and the microalgae species with free copper concentrations measured by an ion selective electrode (ISE), in accordance with the free-ion activity model (FIAM). A significant positive correlation was evident when comparing the bioavailability results measured by the HFSLM and the S. acutus microalga species, showing that the synthetic device may emulate biological uptake and, consequently, be used as a chemical test for bioavailability measurements using this alga as a biological reference. PMID:26431807

  11. Hollow fiber liquid-liquid-liquid microextraction followed by solid-phase microextraction and in situ derivatization for the determination of chlorophenols by gas chromatography-electron capture detection.

    Science.gov (United States)

    Saraji, Mohammad; Ghani, Milad

    2015-10-30

    A method based on the combination of hollow fiber liquid-liquid-liquid microextraction and solid-phase microextraction (SPME) followed by gas chromatography-electron capture detection was developed for the determination of chlorophenols in water and wastewater samples. Silica microstructures fabricated on the surface of a stainless steel wire were coated by an organic solvent and used as a SPME fiber. The analytes were extracted through a hollow fiber membrane containing n-decane from sample solution to an alkaline aqueous acceptor phase. They were then extracted and in situ derivatized on the SPME fiber using acetic anhydride. Experimental parameters such as the type of extraction solvent, acceptor phase NaOH concentration, donor phase HCl concentration, the amount of derivatizing reagent, salt concentration, stirring rate and extraction time were investigated and optimized. The precision of the method for the analytes at 0.02-30μgL(-1) concentration level ranged from 7.1 to 10.2% (as intra-day relative standard deviation) and 6.4 to 9.8% (as inter-day relative standard deviation). The linear dynamic ranges were in the interval of 5-500μgL(-1), 0.05-5μgL(-1), 0.02-1μgL(-1) and 0.001-0.5μgL(-1) for 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol, respectively. The enrichment factors were between 432 and 785. The limits of detection were in the range of 0.0004-1.2μgL(-1). Tap water, well water and wastewater samples were also analyzed to evaluate the method capability for real sample analysis. PMID:26411480

  12. Pretreatment of plasma samples by a novel hollow fiber centrifugal ultrafiltration technique for the determination of plasma protein binding of three coumarins using acetone as protein binding releasing agent.

    Science.gov (United States)

    Li, Junmei; Shi, Qingwen; Jiang, Ye; Liu, Yan

    2015-09-15

    A novel and practical sample pretreatment method based on hollow fiber centrifugal ultrafiltration (HFCF-UF) was developed to determine plasma protein binding by using HPLC. The samples for analyzing unbound and total concentrations could be prepared in parallel simultaneously by the same device. It only required centrifugation for a short time and the filtrate could be injected directly for HPLC analysis without further treatment. Coumarins were selected as the model drugs. Acetone was chosen as the releasing agent to free the binding drug from the drug-protein complex for the total drug concentration determination. Non-specific bindings (NSBs) between the analytes and hollow fiber membrane materials were investigated. The type and volume of protein binding releaser were optimized. Additionally, centrifugal speed and centrifugal time were considered. Under the optimized conditions, the absolute recovery rates of the unbound and total concentrations were in the range of 97.5-100.9% for the three analytes. The limits of detection were in the range of 0.0135-0.0667μgmL(-1). In vitro plasma protein binding of the three coumarins was determined at three concentrations using the validated method and the relative standard deviations (RSDs) were less than 3.4%. Compared with traditional method, the HFCF-UF method is simple to run, no specialized equipment requirement and is a more accurate plasma pretreatment procedure with almost excellent drug-protein binding equilibrium. Therefore, this method can be applied to determine the plasma protein binding in clinical practice. It also provides a reliable alternative for accurate monitoring of unbound or total drug concentration in therapeutic drug monitoring (TDM). PMID:26276065

  13. Mannitol in six autotrophic stramenopiles and Micromonas.

    Science.gov (United States)

    Dittami, Simon M; Aas, Hoai T N; Paulsen, Berit S; Boyen, Catherine; Edvardsen, Bente; Tonon, Thierry

    2011-08-01

    Mannitol plays a central role in brown algal physiology since it represents an important pathway used to store photoassimilate. Several specific enzymes are directly involved in the synthesis and recycling of mannitol, altogether forming the mannitol cycle. The recent analysis of algal genomes has allowed tracing back the origin of this cycle in brown seaweeds to a horizontal gene transfer from bacteria, and furthermore suggested a subsequent transfer to the green microalga Micromonas. Interestingly, genes of the mannitol cycle were not found in any of the currently sequenced diatoms, but were recently discovered in pelagophytes and dictyochophytes. In this study, we quantified the mannitol content in a number of ochrophytes (autotrophic stramenopiles) from different classes, as well as in Micromonas. Our results show that, in accordance with recent observations from EST libraries and genome analyses, this polyol is produced by most ochrophytes, as well as the green alga tested, although it was found at a wide range of concentrations. Thus, the mannitol cycle was probably acquired by a common ancestor of most ochrophytes, possibly after the separation from diatoms, and may play different physiological roles in different classes. PMID:21720212

  14. Biogas desulfurization using autotrophic denitrification process.

    Science.gov (United States)

    Bayrakdar, Alper; Tilahun, Ebrahim; Calli, Baris

    2016-01-01

    The aim of this study was to evaluate the performance of an autotrophic denitrification process for desulfurization of biogas produced from a chicken manure digester. A laboratory scale upflow fixed bed reactor (UFBR) was operated for 105 days and fed with sodium sulfide or H2S scrubbed from the biogas and nitrate as electron donor and acceptor, respectively. The S/N ratio (2.5 mol/mol) of the feed solution was kept constant throughout the study. When the UFBR was fed with sodium sulfide solution with an influent pH of 7.7, about 95 % sulfide and 90 % nitrate removal efficiencies were achieved. However, the inlet of the UFBR was clogged several times due to the accumulation of biologically produced elemental sulfur particles and the clogging resulted in operational problems. When the UFBR was fed with the H2S absorbed from the biogas and operated with an influent pH of 8-9, around 98 % sulfide and 97 % nitrate removal efficiencies were obtained. In this way, above 95 % of the H2S in the biogas was removed as elemental sulfur and the reactor effluent was reused as scrubbing liquid without any clogging problem. PMID:26428238

  15. In situ pre-concentration and voltammetric determination of trace lead and cadmium by a novel ionic liquid mediated hollow fiber-graphite electrode and design of experiments via Taguchi method

    International Nuclear Information System (INIS)

    Highlights: • Asingle-use voltammetry sensor was developed, using ionic liquid mediated hollow fiber-graphite supported nanomagnetite working electrode. • Pb(II) and Cd(II) have been selected as target compounds. • The sensor has been applied to one-step simultaneous purification, pre-concentration, extraction, back-extraction and differential pulse voltammetry(DPV) analysis of analytes in water samples. • The limits of detection are in the low ngmL−1. - Abstract: In this research a single-use voltammetry sensor, incorporating a three electrodes configuration was developed, using ionic liquid mediated hollow fiber-graphite supported nanomagnetite working electrode. These electrodes coupled with differential pulse voltammetry (DPV) provided a screening tool for in-situ pre-concentration and determination of trace levels of Pb(II) and Cd(II). In this design, a two-centimeter piece of porous polypropylene hollow fiber membrane was impregnated with homogeneous mixture of nanomagnetic particles/ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate), and a graphite rod was located inside the fiber lumen. In this sensor, synthesized nanoparticles such as zero-valent Iron (ZVI), nanomagnetite (NM) and magnetic hollow spheres (MHS), dispersed in the ionic liquid, were used for one-step simultaneous purification, pre-concentration and trapping of pb(II) and Cd(II) ions from water samples. The Taguchi method was applied as an experimental design to determine optimum conditions for lead and cadmium ions removal. The experiments were designed, in two steps, according to Taguchi's method, OA16 L18 (21 × 35) and OA16 L16 (21 × 43) orthogonal were arrayed to the optimize experimental runs. Various affective parameters were investigated. The effect of all the input parameters on the output responses was analyzed using analysis of variance (ANOVA). The results revealed that the metal removal was influenced primarily by the amount of nanoparticle (52.18%) and

  16. Hollow fiber based-liquid phase microextraction using ionic liquid solvent for preconcentration of lead and nickel from environmental and biological samples prior to determination by electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    A simple and effective hollow fiber based-liquid phase microextraction (HF-LPME) technique by using ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate, [C6MIM][PF6], coupled with electrothermal atomic absorption spectrometry (ETAAS) was developed for the determination of lead and nickel in environmental and biological samples. Ammonium pyrroldinedithiocarbamate (APDC) was used as chelating agent. Several factors that influence the microextraction efficiency and ETAAS signal, such as pH, APDC concentration extraction time, amounts of ionic liquid, stirring rate, pyrolysis and atomization temperature were investigated and the microextraction conditions were established. In the optimum experimental conditions, the detection limits (3 s) of the method were 0.03 and 0.02 μg L-1, for Ni and Pb, respectively and corresponding relative standard deviations (0.5 μg L-1, n = 6) were 4.2% and 5%. The developed method was validated by the analysis of certified reference materials and applied to the determination of lead and nickel in real samples.

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

    Science.gov (United States)

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

    2016-04-01

    This study describes a combination between hollow fiber membrane and dispersive liquid-liquid microextraction for determination of aflatoxins in soybean juice by HPLC. The main advantage of this approach is the use of non-chlorinated solvent and small amounts of organic solvents. The optimum extraction conditions were 1-octanol as immobilized solvent; toluene and acetone at 1:5 ratio as extraction and disperser solvents (100 μL), NaCl at 2% of the sample volume and extraction time of 60 min. The optimal condition for the liquid desorption was 150 μL acetonitrile:water (50:50 v/v) and desorption time of 20 min. The linear range varied from 0.03 to 21 μg L(-1), with R(2) coefficients ranging from 0.9940 to 0.9995. The limits of detection and quantification ranged from 0.01 μg L(-1) to 0.03 μg L(-1) and from 0.03 μg L(-1) to 0.1 μg L(-1), respectively. Recovery tests ranged from 72% to 117% and accuracy between 12% and 18%. PMID:26593494

  18. Estimating autotrophic respiration in streams using daily metabolism data

    Science.gov (United States)

    Knowing the fraction of gross primary production (GPP) that is immediately respired by autotrophs and their closely associated heterotrophs (ARf) is necessary to understand the trophic base and carbon spiraling in streams. We show a means to estimate ARf from daily metabolism da...

  19. Autotrophic acetyl coenzyme A biosynthesis in Methanococcus maripaludis

    International Nuclear Information System (INIS)

    To detect autotrophic CO2 assimilation in cell extracts of Methanococcus maripaludis, lactate dehydrogenase and NADH were added to convert pyruvate formed from autotropically synthesized acetyl coenzyme A to lactate. The lactate produced was determined spectrophotometrically. When CO2 fixation was pulled in the direction of lactate synthesis, CO2 reduction to methane was inhibited. Bromoethanesulfonate (BES), a potent inhibitor of methanogenesis, enhanced lactate synthesis, and methyl coenzyme M inhibited it in the absence of BES. Lactate synthesis was dependent on CO2 and H2, but H2 + CO2-independent synthesis was also observed. In cell extracts, the rate of lactate synthesis was about 1.2 nmol min-1 mg of protein-1. When BES was added, the rate of lactate synthesis increased to 2.1 nmol min-1 mg of protein-1. Because acetyl coenzyme A did not stimulate lactate synthesis, pyruvate synthase may have been the limiting activity in these assays. Radiolabel from 14CO2 was incorporated into lactate. The percentages of radiolabel in the C-1, C-2, and C-3 positions of lactate were 73, 33, and 11%, respectively. Both carbon monoxide and formaldehyde stimulated lactate synthesis. 14CH2O was specifically incorporated into the C-3 of lactate, and 14CO was incorporated into the C-1 and C-2 positions. Low concentrations of cyanide also inhibited autotrophic growth, CO dehydrogenase activity, and autotrophic lactate synthesis. These observations are in agreement with the acetogenic pathway of autotrophic CO2 assimilation

  20. Denitrification characteristics of a sulfur autotrophic denitrification reactor

    Directory of Open Access Journals (Sweden)

    Chenxiao ZHANG

    2016-02-01

    Full Text Available The denitrification characteristics of a sulfur autotrophic denitrification reactor are investigated. The results show that domestication of sulfur autotrophic bacteria is completed within 15 days after biofilm formation in the reactor, which is shorter than other similar researches. The nitrogen removal rate remains over than 90%, and the denitrification rate reaches 18.5 mg N/(L·h with influent NO-3-N of 70 mg/L , influent pH of 8 and HRT of 4.3 h . Thiobacillus denitrificans are observed in the whole reactor when domestication finishes, while it is more abundant in the middle and lower part. The optimal influent NO-3-N concentration for the reactor is 50 mg/L, the optimal temperature is 30~35 ℃, the optimal influent pH is 7~8, and the nitrogen removal rate is over than 90%.

  1. 同质编织管增强型聚丙烯腈中空纤维膜研究%STUDY ON HOMOGENEOUS BRAIDED TUBE REINFORCED POLYACRYLONITRILE HOLLOW FIBER MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    王瑞; 肖长发; 刘美甜; 张旭良

    2013-01-01

    利用二维编织技术将聚丙烯腈(PAN)纤维编织成中空编织管,以聚丙烯腈为成膜聚合物,以聚乙二醇为成孔剂,配制铸膜液,采用同心圆纺丝法制备同质编织管增强型聚丙烯腈中空纤维膜.研究结果表明,所得同质编织管增强型聚丙烯腈中空纤维膜的表面分离层具有类似于非对称膜的结构,铸膜液可渗入编织管纤维束中;随着编织管编织节距的增大,同质编织管增强型聚丙烯腈中空纤维膜表面分离层厚度减小,同时膜的平均孔径增大,膜的纯水通量随之增大;铸膜液渗入编织管纤维束的现象未影响膜的通透性能;编织管的断裂强度最大可达100 MPa以上.通过水浴振荡、超声波水浴振荡及等力拉伸3种方法测试了同质编织管增强型中空纤维膜和异质编织管增强型中空纤维膜中编织管与表面分离层之间的界面结合性能,结果表明前者的界面结合性能优于后者.%Homogeneous braided tube reinforced polyacrylonitrile ( PAN) hollow fiber membranes which contained hollow braided tube and separation surface were prepared by concentric circles spinning method. The braided tube was prepared by the two-dimensional braided technique using PAN fibers. While the separation surface was obtained by non-solvent induced phase separation method with PAN as the polymer matrix, dimethyl sulfoxide (DMSO) as the solvent,and polyethylene glycol (PEG) as the pore-forming agent. Results showed that the structure of separation surface was similar to asymmetric membrane. The casting solution would penetrate into the voids among fiber bundles of the braided tube. As the braided pitch increasing, the thickness of separation surface decreased, which induced the promotion of the membrane water flux. There was no obvious influence of casting solution penetration on the membrane permeability. The breaking strength of braided tube was up to 100 MPa. Water bath vibration, ultrasonic vibration and

  2. Photo-autotrophic Production of Poly(hydroxyalkanoates) in Cyanobacteria

    OpenAIRE

    Drosg, B.; Fritz, I; Gattermayr, F.; Silvestrini, L.

    2015-01-01

    In the last two decades, poly(hydroxyalkanoates) (PHA) were solely produced using heterotrophic bacteria in aerobic cultivation. With respect to the great potential (500 Mt yr–1) of raw industrial CO2 streams and even greater potential of flue gases, the focus on photo-autotrophic biotechnological processes is increasing steadily. Primarily, PHA-gene transfer from heterotrophic bacteria into algae and plant cells was attempted, with the intention to combine the known biosynthesis pathway with...

  3. Autotrophic growth of nitrifying community in an agricultural soil

    OpenAIRE

    Xia, Weiwei; Zhang, Caixia; Zeng,Xiaowei; Feng, Youzhi; Weng, Jiahua; Lin, Xiangui; Zhu, Jianguo; Xiong, Zhengqin; Xu, Jian; Cai, Zucong; Jia, Zhongjun

    2011-01-01

    The two-step nitrification process is an integral part of the global nitrogen cycle, and it is accomplished by distinctly different nitrifiers. By combining DNA-based stable isotope probing (SIP) and high-throughput pyrosequencing, we present the molecular evidence for autotrophic growth of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB) in agricultural soil upon ammonium fertilization. Time-course incubation of SIP microcosms indicated t...

  4. Comparison of hollow fiber liquid-phase microextraction and ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction for the determination of drugs of abuse in biological samples by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Meng, Liang; Zhang, Wenwen; Meng, Pinjia; Zhu, Binling; Zheng, Kefang

    2015-05-01

    Two microextraction techniques based on hollow fiber liquid-phase microextraction (HF-LPME) and ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction (UA-LDS-DLLME) had been applied for the determination of drugs of abuse (methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine, methcathinone, ketamine, meperidine, and methadone) in urine and blood samples by gas chromatography-mass spectrometry. Parameters affecting extraction efficiency have been investigated and optimized for both methods. Under the optimum conditions, linearities were observed for all analytes in the range 0.0030-10 μg/ml with the correlation coefficient (R) ranging from 0.9985 to 0.9995 for HF-LPME and in the range 0.0030-10 μg/ml with the R ranging from 0.9985 to 0.9994 for DLLME. The recovery of 79.3-98.6% with RSDs of 1.2-4.5% was obtained for HF-LPME, and the recovery of 79.3-103.4% with RSDs of 2.4-5.7% was obtained for DLLME. The LODs (S/N=3) were estimated to be in the range from 0.5 to 5 ng/ml and 0.5 to 4 ng/ml, respectively. Compared with HF-LPME, the UA-LDS-DLLME technique had the advantages of less extraction time, suitability for batches of sample pretreatment simultaneously, and higher extraction efficiency, while HF-LPME has excellent sample clean-up effect, and is a robust and suitable technique for various sample matrices with better repeatability. Both methods were successfully applied to the analysis of drugs of abuse in real human blood sample. PMID:25801996

  5. Fabrication of a novel nanocomposite based on sol-gel process for hollow fiber-solid phase microextraction of aflatoxins: B1 and B2, in cereals combined with high performane liquid chromatography-diode array detection.

    Science.gov (United States)

    Es'haghi, Zarrin; Sorayaei, Hoda; Samadi, Fateme; Masrournia, Mahboubeh; Bakherad, Zohreh

    2011-10-15

    The new pre-concentration technique, hollow fiber-solid phase microextraction based on carbon nanotube reinforced sol-gel and liquid chromatography-photodiode array detection was applied to determination of aflatoxins B(1), B(2) (AFB(1), AFB(2)) in rice, peanut and wheat samples. This research provides an overview of trends related to synthesis of solid phase microextraction (SPME) sorbnents that improves the assay of aflatoxins as the semi-polar compounds in several real samples. It mainly includes summary and a list of the results for a simple carbon nanotube reinforced sol-gel in-fiber device. This device was used for extraction, pre-concentration and determination of aflatoxins B1, B2 in real samples. In this technique carbon nanotube reinforced sol was prepared by the sol-gel method via the reaction of phenyl trimethoxysilane (PTMS) with a basic catalyst (tris hydroxymethyl aminomethan). The influences of microextraction parameters such as pH, ageing time, carbon nanotube contents, desorption conditions, desorption solvent and agitation speed were investigated. Optimal HPLC conditions were: C(18) reversed phase column for separation, water-acetonitril-methanol (35:10:55) as the mobile phase and maximum wavelength for detection was 370 nm. The method was evaluated statistically and under optimized conditions, the detection limits for the analytes were 0.074 and 0.061 ng/mL for B1 and B2 respectively. Limit of quantification for B1 and B2 was 0.1 ng/mL too (n=7). The precisions were in the range of 2.829-2.976% (n=3), and linear ranges were within 0.1 and 400 ng/mL. The method was successfully applied to the analysis of cereals (peanut, wheat, rice) with the relative recoveries from 47.43% to 106.83%. PMID:21925977

  6. 中空纤维超滤法研究核苷类逆转录酶抑制药与DNA的结合率%Study on the Binding Rate of Nucleoside Reverse Transcriptase Inhibitors with DNA by Hollow Fiber Ultrafiltration

    Institute of Scientific and Technical Information of China (English)

    孟彦波; 蒋晔

    2011-01-01

    Objective:To study the binding rate of the reverse transcriptase inhibitors with calf thymus DNA (ct-DNA) by hollow fiber ultrafiltration. Method:The hollow fiber was cut into 15 cm each piece,then put into distilled water and treated by ultrasound for 15 s and used after dring. The solution (adefovir/lamivudine/emtricitabine: DNA = 1:1) of 0.6 ml was put into a thin glass tube with one side sealed. The glass tube with hollow fiber with U-shape was centrifuged with 4 000 r·min-1 for 60 rains. Then the hollow fiber was taken out and 50 μl of the filtrate was drew with the syringe. The filtrate was diluted to 3. 0 ml for UV determination. Result: The average binding rates for adefovir,lamivudine and emtricitabine with DNA were 40.7% ,41.0% and 38.6% .respectively. Conclusion: A method has been established for determination of binding rate as well as binding stability between reverse transcriptase inhibitors and DNA.%目的:采用中空纤维超滤法研究核苷类逆转录酶抑制剂类药物与小牛胸腺DNA(ct-DNA)的相互结合率.方法:将中空纤维切成约15 cm小段,放入重蒸水中超声清洗15 s,晾干、备用.分别取阿德福韦(PMEA)、拉米夫定(LMVD)和恩曲他滨(FTC)与DNA摩尔比为1:1的混合液0.6ml于一端封闭的细玻璃管中,玻璃管中再放入弯曲成U型的中空纤维,置离心机中离心(4 000 r·min-1 )60 min后,取出中空纤维,用微量进样器抽出中空纤维内液体约50μl,稀释至3.0 ml后分别测其最大紫外吸收.结果:PMEA、LMVD、FTC与DNA的平均结合率分别为40.7%、41.0%、38.6%.结论:确定了核苷类逆转录酶抑制剂类药物与DNA结合率的测定方法,可表征药物与DNA的结合强度.

  7. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    OpenAIRE

    B. Veuger; Pitcher, A.; Schouten, S.; Sinninghe Damsté, J.S.; Middelburg, J. J.

    2013-01-01

    Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absen...

  8. Experimental study on separation of CO2 by polypropylene hollow fiber membrane contactor%聚丙烯中空纤维膜组件分离烟气中的CO2

    Institute of Scientific and Technical Information of China (English)

    瞿如敏; 沙焱; 陈浩; 杨林军

    2013-01-01

    This research presented separation of CO2 from flue gas by polypropylene(PP) hollow fiber membrane contactors,using aqueous solution of monoethanolamine (MEA) as absorption solvents. Effects of operating conditions,water vapor and SO2 on the performance and integrity of the membrane were investigated. The results showed that the best liquid-gas ratio was 24 L/m3,the concentration of MEA was 0.6 mol/L and temperature at the contactor entrance had little effect on absorption efficiency. The concentration of CO2 had little effect on absorption efficiency when the concentration was in the range of 10%-20%. The adsorption of SO2 is prior to CO2,but it isn’t obvious for the low concentration of SO2. Adsorption of water vapor on the hole walls of membrane contactors forms capillary condensation,preventing the penetration of CO2.%膜吸收法在大型工业燃煤电厂二氧化碳(CO2)捕集方面具有很好的应用前景,但烟气组分对该技术效果影响还有待进一步研究。本文以单乙醇胺(MEA)为吸收剂,开展了疏水性聚丙烯(PP)中空纤维膜组件分离模拟烟气中的 CO2的实验研究,考察了吸收操作条件以及燃煤烟气中水汽和 SO2对膜组件吸收效率的影响。结果表明,试验的最佳液气比为24 L/m3;MEA的浓度为0.6 mol/L;膜组件进口的温度变化对吸收效率基本没有影响;CO2的浓度在10%~20%内变动对吸收效率影响不大。与CO2相比,SO2会优先发生吸收作用,而水汽则会吸附在聚丙烯中空纤维膜组件的孔壁上,产生毛细管凝聚现象,阻塞CO2的渗透吸收。

  9. Ultrafiltration of soybean whey using reciprocating rotation hollow-fiber membrane module%往复旋转式中空纤维超滤膜处理大豆乳清

    Institute of Scientific and Technical Information of China (English)

    吕斯濠; 张晓娜; 梁志辉; 曾燕艳; 范洪波

    2014-01-01

    A novel dynamic filtration device with reciprocating rotation hollow fiber membrane was used in the ultrafiltration of soybean whey. Effects of filtration modes and reciprocating rotating parameters on the permeate fluxes of membrane were investigated. A 2D particle image velocimetry (PIV) was used to capture the fluid hydrodynamics, and the energy consumption was measured for analyzing the energy efficiency. Results show that the decline of permeate flux is greatly reduced under reciprocating rotation conditions. Higher rotation speed and lower reciprocating rotation cycle increase the velocity gradient at membrane surface, specific energy consumption and membrane permeate flux. With a relatively higher angular speed of membrane fibers, the effect of reciprocating rotating cycles on membrane permeability is more significant. The membrane permeate yields can be represented by a power function of fluid velocity gradient. A polynomial function is used to describe the correlation between specific energy consumption and fluid velocity gradient. The present specific energy consumption values are larger than that of some previous researches.%采用往复旋转式中空纤维超滤膜装置处理大豆乳清液,实验结果表明,该装置利用膜的旋转速度与料液的流动速度之间的矢量叠加,形成较高的速度梯度,从而很好地延缓膜通量的衰减。增大旋转速度或缩短往复周期均会在膜表面形成更大的流体速度梯度,进而产生更好的剪切强化效果,延缓膜通量的衰减。当旋转速度较高时,改变往复周期对膜过滤通量的影响更明显。回归分析表明,膜总透过液量与速度梯度之间存在一个幂函数关系。能耗分析的结果表明,单位通量能耗率随膜表面流体速度梯度的增大而增大,二者之间的关系接近于一个多项式。

  10. 往复旋转中空纤维膜处理脱脂奶水溶液%Research on skim milk ultrafiltration with a reciprocating rotating hollow fiber membrane module

    Institute of Scientific and Technical Information of China (English)

    张杰琳; 范洪波; 王莘; 杨田龙; 吕斯濠

    2012-01-01

    A novel dynamic filtration system of reciprocating rotating hollow fiber membrane was used to UF skim milk solution.The effects of the module's geometry parameters and rotating parameters as well as the characteristics of tested fluid on the decline of membrane permeate flux were investigated.The results indicated that a better shear enhancing efficiency could be obtained while the angular velocity and/or the radial distance of membranes from the central hollow shaft were increased.The greater vectors superposition of the flow field and the membrane rotating velocity,which was reflected on a relative greater velocity gradient,would be obtained once the reciprocating rotation cycle was optimized.Otherwise,simply increasing or decreasing the rotation cycle would weaken the efficiency of shear enhancement.With the same operating parameters,the reciprocating rotation filtration was more favorable in slowing the decline of membrane permeate flux than the dead end filtration or the uni-directional rotation filtration.%采用一种往复旋转中空纤维膜超滤装置处理脱脂奶水溶液,考察了该膜过滤装置的结构参数、膜组件旋转参数以及料液的特征参数等对膜渗透通量衰减的影响。结果表明,旋转角速度越大,膜丝距中空轴轴心越远,往复旋转中空纤维膜的剪切强化作用越好;往复旋转周期的优化则需考虑如何使料液流场流速与膜丝转速之间的矢量迭加在膜表面产生的速度梯度更大,单纯增大或减小旋转周期均会弱化剪切强化的效果。在同样操作参数下,往复旋转方式比死端过滤及单向旋转方式的膜过滤更利于延缓膜通量衰减。

  11. 中空纤维支撑液膜萃取法提铟工艺比较研究%THE COMPARATIVE STUDY OF THREE CONFIGURATIONS OF HOLLOW FIBER SUPPORTED LIQUID MEMBRANE PROCESSES FOR In(Ⅲ) EXTRACTION

    Institute of Scientific and Technical Information of China (English)

    冯海波; 贾悦; 吕晓龙; 刘薇; 苏烨; 卢卫球

    2012-01-01

    采用中空纤维支撑液膜( SLM)技术,模拟酸生铟渣浸出液,以磷酸二异辛酯(P204)、磺化煤油体积比3∶7为液膜萃取相,盐酸溶液为反萃相,研究了单组件膜萃取系统、双膜组件萃取-反萃系统、双膜组件萃取-超滤系统对酸性浸出液中In的提取与分离效率.结果表明,双膜组件萃取-超滤技术可同时实现浸出液中In的提取与反萃液中In的高纯度富集,浸出液中In的提取率可达90%以上,反萃液中In含量可达浸出液中In含量的70%,In的质量分数高于90%.%The extraction and separation efficiency in the acidic leach solution by single-module extraction system, two-modules extraction and stripping system, two-modules extraction and ultra-filtration system, using hollow fiber supported liquid membrane (FHSLM) processes, simulating acidic indium slag leaching solution , D2EHPA/sulfonated kerosene whose volume ratio was 3:7 as liquid membrane phase, HC1 aqueous solution as stripping phase were studied. The results showed that the two-modules extraction and ultra-filtration system can successfully separate and enrich In(III) in the stripping solution. The extraction rate of the system from the acid leaching solution could be above 90%, In(III) content in the stripping phase could be above 70% of its initial value in the feed. In addition, In(III) purity in the stripping solution was higher than 90%.

  12. In-line sequential injection-based hollow-fiber sorptive microextraction as a front-end to gas chromatography-mass spectrometry: a novel fully automatic sample processing technique for residue analysis.

    Science.gov (United States)

    Boonjob, Warunya; Quintana, José Benito; Rodil, Rosario; Cela, Rafael; Miró, Manuel

    2013-10-01

    A novel and affordable analytical setup is herein reported for automatic flow-through sorptive microextraction of organic contaminants, exploiting polydimethylsiloxane (PDMS) as a front-end to gas chromatography-ion trap-tandem mass spectrometry. The analytical procedure involves a short single-strand PDMS hollow fiber integrated in a sequential injection (SI) network for automatic fluidic handling by programmable flow. The target species are in-line extracted from 10 mL of sample containing 20% (v/v) methanol followed by elution with a metered volume of organic solvent, which is whereupon quantitatively transferred into the programmed temperature vaporization (PTV) injector of the GC. Diffusional resistance to mass transfer was overcome by effecting the overall concentration and stripping steps at a single PDMS tubing interface. The proof of concept of the novel hyphenated system was demonstrated for extraction and determination of organochlorine pesticides (OCPs), namely, heptachlor, dieldrin, endrin, endosulfan, p,p'-dichlorodiphenyldichloroethane, p,p'-dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethylene, and endrin ketone, taken as model analytes, in environmental and industrial waters. Four organic solvents with a broad spectrum of polarity were investigated as eluents in the SI-based assembly, namely, ethyl acetate, methyl tert-butyl ether, hexane, and chloroform. Chloroform was proven the most suitable solvent for expedient elution and fast evaporation in the PTV injector. Under the selected experimental variables, limits of detection (signal-to-noise ratio (S/N) = 3) within the range of 0.3-1.1 ng L(-1), limits of quantification (S/N = 10) of 1.0-3.6 ng L(-1), and method repeatabilities spanning from 1.7 to 4.7% were obtained for the suite of OCPs. The hyphenated flow analyzer was harnessed to the analysis of samples of varying matrix complexity with good relative recoveries (86-112%) in drinking water, surface water, and influent and effluent

  13. Lipid-based liquid biofuels from autotrophic microalgae: energetic and environmental performance

    NARCIS (Netherlands)

    L. Reijnders

    2013-01-01

    Commercial cultivation of autotrophic microalgae for food production dates back to the 1950s. Autotrophic microalgae have also been proposed as a source for lipid-based liquid biofuels. As yet, there is no commercial production of such biofuels and estimated near-term prices are far in excess of fos

  14. Autotrophic nitrogen removal in one lab-scale vertical submerged biofilm reactor

    Science.gov (United States)

    Liang, Zhiwei; Chen, Yingxu; Li, Wenhong; Yang, Shangyuan; Du, Ping

    In this study, the process performance of a new vertical submerged biofilm reactor for complete autotrophic ammonia removal was investigated using synthetic wastewater. The main objectives of this study were to evaluate the flexibility of the reactor, achieve partial autotrophic nitrification with influent ammonium nitrogen ranging from 40 to 280 mg L -1, and achieve a stable half partial autotrophic nitrification by controlling hydraulic retention time (HRT) and alkalinity. A very low concentration of nitrate was observed in the effluent during nitrification. Then autotrophic denitrification revealed Anammox bacteria were present and active in the central anaerobic parts of the bioreactor which was inoculated with a mixed microbial consortium from activated sludge. The results of this study demonstrated that autotrophic denitrification processes can coexist with heterotrophic denitrifying processes in the same environment even if Anammox bacteria were less competitive than heterotrophic denitrifying bacteria.

  15. Autotrophic and heterotrophic activity in Arctic first-year sea ice: seasonal study from Malene Bight, SW Greenland

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Kristensen, Morten; Rysgaard, Søren; Glud, Ronnie Nøhr; Hansen, Per Juel; Hillingsøe, Karen Marie

    2010-01-01

    followed by an algal bloom in late March and April, leading to a net autotrophic community. During February and March, the oxygen level in the bag incubations remained constant, validating the low balanced heterotrophic and autotrophic activity. As the autotrophic activity exceeded the heterotrophic...

  16. Structure, composition, and strength of nitrifying membrane-aerated biofilms

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Smets, Barth F.

    2014-01-01

    achieve full nitrification revealed a significantly different structure of nitrifying MABR biofilms with respect to its co-diffusion counterparts reported in the literature (up to now assumed to have similar properties). Different levels of shear stress and oxygen loadings during MABR operation also...

  17. Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

    OpenAIRE

    Meijer, Wilhelmus Gerhardus

    1990-01-01

    Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O), pbosphoribulokinase (PRK) and fructosebisphosphatase (FBPase) are the unique enzymes of this autotrophic pathway (Chapter 1). ... Zie: Summary

  18. Current views on the regulation of autotrophic carbon dioxide fixation via the Calvin cycle in bacteria

    OpenAIRE

    Dijkhuizen, L; Harder, W

    1984-01-01

    The Calvin cycle of carbon dioxide fixation constitutes a biosynthetic pathway for the generation of (multi-carbon) intermediates of central metabolism from the one-carbon compound carbon dioxide. The product of this cycle can be used as a precursor for the synthesis of all components of cell material. Autotrophic carbon dioxide fixation is energetically expensive and it is therefore not surprising that in the various groups of autotrophic bacteria the operation of the cycle is under strict m...

  19. Investigation of mixotrophic, heterotrophic, and autotrophic growth of Chlorella vulgaris under agricultural waste medium.

    Science.gov (United States)

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-01-01

    Growth of Chlorella vulgaris and its lipid production were investigated under autotrophic, heterotrophic, and mixotrophic conditions. Cheap agricultural waste molasses and corn steep liquor from industries were used as carbon and nitrogen sources, respectively. Chlorella vulgaris grew remarkably under this agricultural waste medium, which resulted in a reduction in the final cost of the biodiesel production. Maximum dry weight of 2.62 g L(-1) was obtained in mixotrophic growth with the highest lipid concentration of 0.86 g L(-1). These biomass and lipid concentrations were, respectively, 140% and 170% higher than autotrophic growth and 300% and 1200% higher than heterotrophic growth. In mixotrophic growth, independent or simultaneous occurrence of autotrophic and heterotrophic metabolisms was investigated. The growth of the microalgae was observed to take place first heterotrophically to a minimum substrate concentration with a little fraction in growth under autotrophic metabolism, and then the cells grew more autotrophically. It was found that mixotrophic growth was not a simple combination of heterotrophic and autotrophic growth. PMID:25807048

  20. Morphology and physiology of facultative autotrophic coryneformic bacteria with ability of carbon monoxide oxidation

    International Nuclear Information System (INIS)

    Two coryneform bacterial strains (IFAM 1131 and IFAM 1133) capable of living on CO as the sole energy and carbon source were selected from a number of co-tolerant bacteria and studied more closely. Both strains could provisionally be grouped in the genera Arthrobacter. Their ability for hetorotrophic growth with a variety of C-sources and also autotrophic growth under CO and H2 atmospheric conditions characterised the test strains as facultative autotrophs. They could clearly be distinguished from all other CO- and H2-autotrophic bacterial strains described in the literature. Studies on strain IFAM 1131 using 14CO shared that for CO-autotrophic growth, carbon monoxide is oxidised to CO2. Ribulose 1,5-bisphosphate carboxylase activity, only found in autotrophically - grown cells, provided evidence for CO2 as the C-source and its fixation via the calvin cycle. The CO-oxidising system was also active in the absence of CO2. Gas chromatographically determined conversion rates for CO-autotrophically-grown static cultures of the strain IFAM 1131 revealed that some 20% of the CO oxidised to CO2 was fixed during logarithmic growth. (orig./MG)

  1. Expanding leaves of mature deciduous forest trees rapidly become autotrophic.

    Science.gov (United States)

    Keel, Sonja G; Schädel, Christina

    2010-10-01

    Emerging leaves in evergreen tree species are supplied with carbon (C) from the previous year's foliage. In deciduous trees, no older leaves are present, and the early phase of leaf development must rely on C reserves from other tissues. How soon developing leaves become autotrophic and switch from being C sinks to sources has rarely been studied in mature forest trees, and simultaneous comparisons of species are scarce. Using a canopy crane and a simple (13)CO(2)-pulse-labelling technique, we demonstrate that young leaves of mature trees in three European deciduous species (Fagus sylvatica L., Quercus petraea (Matt.) Liebl., Tilia platyphyllos Scop.) start assimilating CO(2) at a very early stage of development (10-50% expanded). One month after labelling, all leaves were still strongly (13)C enriched, suggesting that recent photosynthates had been incorporated into slow turnover pools such as cellulose or lignin and thus had contributed to leaf growth. In line with previous studies performed at the same site, we found stronger incorporation of recent photosynthates into growing tissues of T. platyphyllos compared with F. sylvatica and Q. petraea. Non-structural carbohydrate (NSC) concentrations analysed for one of the three study species (F. sylvatica) showed that sugar and starch pools rapidly increased during leaf development, suggesting that newly developed leaves soon produce more NSC than can be used for growth. In conclusion, our findings indicate that expanding leaves of mature deciduous trees become C autonomous at an early stage of development despite the presence of vast amounts of mobile carbohydrate reserves. PMID:20688879

  2. 应用中空纤维测定法评价藤甲酰苷对人癌细胞生长的抑制作用%Evaluation of the inhibitory effect of garcinia glycosides on growth of human tumor cells by hollow fiber assay

    Institute of Scientific and Technical Information of China (English)

    邓晶晶; 纪圣君; 陈烨; 林晓琳; 王蕊; 徐利锋

    2014-01-01

    Objective To evaluated the inhibitory effect of garcinia glycosides on growth of 8 kinds of human tumor cells in vi-vo by hollow fiber assay and confirm the reliability of hollow fiber assay in anticancer effect by the nude mice xenograft test .Methods Hollow fibers containing tumor cells were inserted underneath the skin of the NOD /SCID mice.The fibers were collected from the mice on the day after the administration and subjected to the stable endpoint MTT assay .The tumor cells of HL-60 and B16 were subcutane-ously implanted into the right flank of BALb /c nude mice.The positive control group was treated with cyclophosphamide .Each group was administered for 10 days.24 hours after the last administration , the mice were sacrificed and the tumors were excised and weigh-ted, the inhibition rate of tumor growth was calculated .Results The high-dose group of 8 mg/( kg· d) , middle dose group of 4 mg/( kg· d) of garcinia glycosides were measured by hollow fiber assay and nude mice test significantly inhibited the in vivo growth of HL -60 and B16 comparing with those in the solvent control group (P<0.01).Conclusion As a new model by hollow fiber assay to evalu-ate the inhibitory effect of garcinia glycosides , the test results were basically the same with nude mice test results .It made the experi-ment more rapidly , accurately and economically .An instruction and reliable evidence for follow-up study of garcinia glycosides was provided in this study .%目的:应用中空纤维测定法评价藤甲酰苷( garcinia glycosides ,GG)对8种人癌细胞的体内生长的抑制作用,通过裸鼠体内异位移植瘤实验,验证中空纤维测定法在抗肿瘤药效学研究中的可靠性。方法采用中空纤维测定法,将载有肿瘤细胞的中空纤维管植入NOD/SCID小鼠背部皮下,给药结束后取出中空纤维管,应用二苯基溴化四氮唑蓝( MTT)比色法检测GG对各种肿瘤细胞在体内的抑瘤率;选取HL-60及B16

  3. Sulfide-driven autotrophic denitrification significantly reduces N2O emissions.

    Science.gov (United States)

    Yang, Weiming; Zhao, Qing; Lu, Hui; Ding, Zhi; Meng, Liao; Chen, Guang-Hao

    2016-03-01

    The Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI) process build on anaerobic carbon conversion through biological sulfate reduction and autotrophic denitrification by using the sulfide byproduct from the previous reaction. This study confirmed extra decreases in N2O emissions from the sulfide-driven autotrophic denitrification by investigating N2O reduction, accumulation, and emission in the presence of different sulfide/nitrate (S/N) mass ratios at pH 7 in a long-term laboratory-scale granular sludge autotrophic denitrification reactor. The N2O reduction rate was linearly proportional to the sulfide concentration, which confirmed that no sulfide inhibition of N2O reductase occurred. At S/N = 5.0 g-S/g-N, this rate resulted by sulfide-driven autotrophic denitrifying granular sludge (average granule size = 701 μm) was 27.7 mg-N/g-VSS/h (i.e., 2 and 4 times greater than those at 2.5 and 0.8 g-S/g-N, respectively). Sulfide actually stimulates rather than inhibits N2O reduction no matter what granule size of sulfide-driven autotrophic denitrifying sludge engaged. The accumulations of N2O, nitrite and free nitrous acid (FNA) with average granule size 701 μm of sulfide-driven autotrophic denitrifying granular sludge engaged at S/N = 5.0 g-S/g-N were 4.7%, 11.4% and 4.2% relative to those at 3.0 g-S/g-N, respectively. The accumulation of FNA can inhibit N2O reduction and increase N2O accumulation during sulfide-driven autotrophic denitrification. In addition, the N2O gas emission level from the reactor significantly increased from 14.1 ± 0.5 ppmv (0.002% of the N load) to 3707.4 ± 36.7 ppmv (0.405% of the N load) as the S/N mass ratio in the influent decreased from 2.1 to 1.4 g-S/g-N over the course of the 120-day continuous monitoring period. Sulfide-driven autotrophic denitrification may significantly reduce greenhouse gas emissions from biological nutrient removal when sulfur conversion processes are applied. PMID

  4. Woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process for nitrate contaminated water remediation.

    Science.gov (United States)

    Li, Rui; Feng, Chuanping; Hu, Weiwu; Xi, Beidou; Chen, Nan; Zhao, Baowei; Liu, Ying; Hao, Chunbo; Pu, Jiaoyang

    2016-02-01

    Nitrate contaminated water can be effectively treated by simultaneous heterotrophic and autotrophic denitrification (HAD). In the present study, woodchips and elemental sulfur were used as co-electron donors for HAD. It was found that ammonium salts could enhance the denitrifying activity of the Thiobacillus bacteria, which utilize the ammonium that is produced by the dissimilatory nitrate reduction to ammonium (DNRA) in the woodchip-sulfur based heterotrophic and autotrophic denitrification (WSHAD) process. The denitrification performance of the WSHAD process (reaction constants range from 0.05485 h(-1) to 0.06637 h(-1)) is better than that of sulfur-based autotrophic denitrification (reaction constants range from 0.01029 h(-1) to 0.01379 h(-1)), and the optimized ratio of woodchips to sulfur is 1:1 (w/w). No sulfate accumulation is observed in the WSHAD process and the alkalinity generated in the heterotrophic denitrification can compensate for alkalinity consumption by the sulfur-based autotrophic denitrification. The symbiotic relationship between the autotrophic and the heterotrophic denitrification processes play a vital role in the mixotrophic environment. PMID:26650451

  5. Diversity and succession of autotrophic microbial community in high-elevation soils along deglaciation chronosequence.

    Science.gov (United States)

    Liu, Jinbo; Kong, Weidong; Zhang, Guoshuai; Khan, Ajmal; Guo, Guangxia; Zhu, Chunmao; Wei, Xiaojie; Kang, Shichang; Morgan-Kiss, Rachael M

    2016-10-01

    Global warming has resulted in substantial glacier retreats in high-elevation areas, exposing deglaciated soils to harsh environmental conditions. Autotrophic microbes are pioneering colonizers in the deglaciated soils and provide nutrients to the extreme ecosystem devoid of vegetation. However, autotrophic communities remain less studied in deglaciated soils. We explored the diversity and succession of the cbbL gene encoding the large subunit of form I RubisCO, a key CO2-fixing enzyme, using molecular methods in deglaciated soils along a 10-year deglaciation chronosequence on the Tibetan Plateau. Our results demonstrated that the abundance of all types of form I cbbL (IA/B, IC and ID) rapidly increased in young soils (0-2.5 years old) and kept stable in old soils. Soil total organic carbon (TOC) and total nitrogen (TN) gradually increased along the chronosequence and both demonstrated positive correlations with the abundance of bacteria and autotrophs, indicating that soil TOC and TN originated from autotrophs. Form IA/B autotrophs, affiliated with cyanobacteria, exhibited a substantially higher abundance than IC and ID. Cyanobacterial diversity and evenness increased in young soils (<6 years old) and then remained stable. Our findings suggest that cyabobacteria play an important role in accumulating TOC and TN in the deglaciated soils. PMID:27465079

  6. Determination of salicylic acid in environmental waters by hollow fiber membrane assisted ionic liquid-based liquid-liquid microextraction coupled with high-performance liquid chromatography%中空纤维膜辅助离子液体液相微萃取-高效液相色谱法测定环境水体中的水杨酸

    Institute of Scientific and Technical Information of China (English)

    张祯; 江静; 邹艳敏; 吴向阳

    2012-01-01

    Salicylic acid (2-hydroxybenzoic acid, SA) is one of emerging environmental contaminants, which could cause potential ecological risks and impact on human health. So it is necessary to develop an appropriate analytical method to detect the compound in environmental waters. In this study, using ionic liquid ( 1-octyl-3- methylimidazolium hexafluorophosphate, [ C8MIM] [ PF6 ] ) as an extracting agent and tri-n-octylphosphineoxide (TOPO) as an additive, hollow fiber membrane-based liquid phase microextraction combined with highperformance liquid chromatography was developed for the determination of SA in environmental water. Parameters that could influence the extraction performance were optimized, including hollow fiber membrane, species and volume of extraction solvent, sample pH and salinity, as well as extraction time. The developed method offered high enrichment factor (1653), low detection limit (0.1μg. L-1, RSD = 8.4%, n = 6) and good linear range (0.5-1000μg.L-1). The proposed method was applied to determine SA in a variety of environmental waters, and satisfactory recoveries ( 89.6%-102.4% ) were obtained, indicating that the proposed method is a reliable sample pre-treatment procedure that can be applied to determining SA in aquatic environment.%分别以1-辛基-3-甲基咪唑六氟磷酸离子液体([CsMIM][PF6])和三辛基氧化膦(TOPO)作为萃取剂与辅助萃取剂,建立了中空纤维膜辅助的两相液液微萃取-高效液相色谱测定环境水体中水杨酸(Salicylicacid,SA)的新方法.通过对中空纤维膜种类、萃取剂、供体相体积、供体相pH、离子强度和萃取时间相关参数进行优化,获得了较高的富集倍数(1653倍).方法的检出限为0.1μg·L-1,线性范围为0.5-1000μg·L-1.方法对实际样品的加标回收率为89.6%-102.4%,可应用于环境水体中痕量sA的测定.

  7. Hollow-fiber liquid phase microextraction and application in determining pKb of alkaloids%中空纤维液相微萃取及其在生物碱解离常数测定中的应用

    Institute of Scientific and Technical Information of China (English)

    张静; 陈璇; 白小红; 马文艳; 张丽沙

    2012-01-01

    目的 探讨中空纤维液相微萃取(HFLPME)对药根碱、黄连碱、巴马汀、小檗碱的萃取行为;揭示供相OH-(H+)浓度对碱(酸)性分析物HFLPME浓缩倍数的影响规律,利用此规律测定弱碱性分析物的解离常数(pKb).方法 液相微萃取以聚丙烯中空纤维为溶剂载体,正辛醇作为萃取溶剂,供相为10-4 mol/L 的氢氧化钠溶液,接受相为10-2 mol/L 盐酸溶液,搅拌速度1200 r/min,萃取时间60 min.结果 在优化的HFLPME 条件下,4 种分析物药根碱、黄连碱、巴马汀、小檗碱的的富集倍数在12.9~64.6 倍;pKb分别为6.95,3.30,3.40 和4.08.结论 HFLPME的成功应用为碱性化合物的pKb的测定提供了理论依据和实验方法.%Objective To investigate the extraction behaviors of hollow-fiber liquid phase microextraction (HFLPME) on jatrorrhizine, coptisine, palmatine and berberine for revealing the impacts of OH- (H+) concentration in donor phase on enrichment of alkaline or acidic HFLPME analytes, thereby offering tools for measurement of pKb of weak alkaline analytes. Methods For liquid phase microextraction, polypropylene hollow-fiber was selected as the solvent carrier and n-octanol served as extraction solvent. The donor phase was 10-4 mol/L sodium hydroxide and the acceptor phase was 10-2 mol/L hydrochloric acid, with the stirring rate of 1200 r/min and extraction duration of 60 minutes. Results Under optimized extraction conditions, the pKb, for jatrorrhizine, coptisine, palmatine and berberine was 6.95, 3.30, 3.40 and 4.08, respectively, with the enrichment factors ranging from 12.9 to 64.6. Conclusion The successful application of HFLPME has provided theoretical basis and experimental approaches for measurement of pKb of alkaline compounds.

  8. Elemental sulfur formation and nitrogen removal from wastewaters by autotrophic denitrifiers and anammox bacteria.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Yan, Laihong; Wang, Aijie; Gu, Yingying; Lee, Duu-Jong

    2015-09-01

    Elemental sulfur (S(0)) formation from and nitrogen removal on sulfide, nitrate and ammonium-laden wastewaters were achieved by denitrifying ammonium oxidation (DEAMOX) reactor with autotrophic denitrifiers and anaerobic ammonium oxidation (anammox) bacteria. The sulfide to nitrate ratio is a key process parameter for excess accumulation of S(0) and a ratio of 1.31:1 is a proposed optimum. The Alishewanella, Thauera and Candidatus Anammoximicrobium present respectively the autotrophic denitrifiers and anammox bacteria for the reactor. DEAMOX is demonstrated promising biological process for treating organics-deficient (S+N) wastewaters with excess S(0) production. PMID:26022701

  9. Effect of heterotrophic versus autotrophic food on feeding and reproduction of the calanoid copepod Acartia tonsa : relationship with prey fatty acid composition

    DEFF Research Database (Denmark)

    Broglio, E.; Jonasdottir, Sigrun; Calbet, A.; Jakobsen, Hans Henrik; Saiz, E.

    2003-01-01

    ) and ingestion rates, or as the quotient: EPR/ingestion rate. The diets, offered in monoculture, were the heterotrophic ciliates Strombidium sulcatum or Mesodinium pulex, the heterotrophic dinoflagellate Gymnodinium dominans, the autotrophic cryptophyte Rhodomonas salina and the autotrophic...

  10. Regulation of carbon dioxide fixation in facultatively autotrophic bacteria. A phisiological and genetical study.

    NARCIS (Netherlands)

    Meijer, Wilhelmus Gerhardus

    1990-01-01

    Autotrophic bactcria are capable of CO2 fixation via the Calvin cycle, emplofng energy derived from the oxidation of anorganic substrates (e.g. Hz), simple organic substrates (one-carbon compounds, e.g. methanol, formate), or from light. Ribulose-1,5-bisphospbate carboxylase/oxygenase (RuBisC/O), pb

  11. Estimation of autotrophic soil respiration in a boreal forest using three different approaches

    Science.gov (United States)

    Kulmala, Liisa; Pumpanen, Jukka; Heinonsalo, Jussi

    2016-04-01

    It is generally challenging to separate autotrophic and heterotrophic soil respiration. The reason for these difficulties is connected with the intimate interaction of the key processes in soil. Root-associated microbes practically colonize the whole soil volume while decomposition processes occur in the same matrix. Therefore, autotrophic and heterotrophic processes cannot be separated in natural systems. However, there are several methods that can be used to better understand the dynamics of these two. A classical method is called 'trenching' where a trench is dug around a known volume of soil and the roots entering the soil are cut from the living trees thus blocking the C flow from them. The second way to separate autotrophic and heterotrophic respiration relies on the difference in the isotopic signature (13C) of plant-derived or decomposition-derived CO2. The third way to separate the sources is to study the differences in the short- and long-term temperature dependencies in CO2 soil emissions. This is possible especially in boreal forests where the biological activity has a strong seasonal cycle. We compared these three methods in an experiment conducted in a southern boreal middle-aged Scots pine stand in Finland. Our data provides a unique possibility to critically evaluate current methods for estimating autotrophic and heterotrophic soil respiration. The knowledge is needed to study further plant physiology and plant-microbe interactions in soil.

  12. Fluidization velocity assessment of commercially available sulfur particles for use in autotrophic denitrification biofilters

    Science.gov (United States)

    There has been no evaluation of sulfur-based autotrophic denitrification using fluidized biofilters in a recirculating aquaculture system to mitigate nitrate-nitrogen loads. The objectives of this work were to quantify the particle size distribution, specific surface area, and fluidization velocitie...

  13. Expression of Heterogenous Arsenic Resistance Genes in the Obligately Autotrophic Biomining Bacterium Thiobacillus ferrooxidans

    OpenAIRE

    Peng, Ji-Bin; Yan, Wang-Ming; Bao, Xue-Zhen

    1994-01-01

    Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation. The plasmids with the replicon of wide-host-range plasmid RSF1010 were stable in T. ferrooxidans. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacterium, but the promoter derived from T. ferrooxidans showed no special function in its original host.

  14. Autotrophic nitrogen removal from low strength waste water at low temperature

    NARCIS (Netherlands)

    Hendrickx, T.L.G.; Wang, Y.; Kampman, C.; Zeeman, G.; Temmink, B.G.; Buisman, C.J.N.

    2012-01-01

    Direct anaerobic treatment of municipal waste waters allows for energy recovery in the form of biogas. A further decrease in the energy requirement for waste water treatment can be achieved by removing the ammonium in the anaerobic effluent with an autotrophic process, such as anammox. Until now, an

  15. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    Directory of Open Access Journals (Sweden)

    Christine eSharp

    2012-08-01

    Full Text Available Genomic analysis of the methanotrophic verrucomicrobium Methylacidiphilum infernorum strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo, ‘universal’ pmoA polymerase chain reaction (PCR primers do not target these bacteria. Unlike proteobacterial methanotrophs, Methylacidiphilum fixes carbon autotrophically, and uses methane only for energy generation. As a result, techniques used to detect methanotrophs in the environment such as 13CH4-stable isotope probing (SIP and pmoA-targeted PCR do not detect verrucomicrobial methanotrophs, and they may have been overlooked in previous environmental studies. We developed a modified SIP technique to identify active methanotrophic verrucomicrobia in the environment by labelling with 13CO2 and 13CH4, individually and in combination. Testing the protocol in M. infernorum strain V4 resulted in assimilation of 13CO2 but not 13CH4, verifying its autotrophic lifestyle. To specifically detect methanotrophs (as opposed to other autotrophs via 13CO2-SIP, a quantitative PCR (qPCR assay specific for verrucomicrobial-pmoA genes was developed and used in combination with SIP. Incubation of an acidic, high-temperature geothermal soil with 13CH4 + 12CO2 caused little shift in the density distribution of verrucomicrobial-pmoA genes relative to controls. However, labelling with 13CO2 in combination with 12CH4 or 13CH4 induced a strong shift in the distribution of verrucomicrobial-pmoA genes towards the heavy DNA fractions. The modified SIP technique demonstrated that the primary methanotrophs active in the soil were autotrophs and belonged to the Verrucomicrobia. This is the first demonstration of autotrophic, non-proteobacterial methanotrophy in situ, and provides a tool to detect verrucomicrobial methanotrophs in other ecosystems.

  16. Stimulation of autotrophic denitrification by intrusions of the Bosporus Plume into the anoxic Black Sea

    Directory of Open Access Journals (Sweden)

    Clara A. Fuchsman

    2012-07-01

    Full Text Available Autotrophic denitrification was measured in the southwestern coastal Black Sea, where the Bosporus Plume injects oxidized chemical species (especially O2 and NO3- into the oxic, suboxic and anoxic layers. Prominent oxygen intrusions caused an overlap of NOx- and sulfide at the same station where autotrophic denitrification activity was detected with incubation experiments. Several bacteria that have been proposed to oxidize sulfide in other low oxygen environments were found in the Black Sea including SUP05, Sulfurimonas, Arcobacter, and BS-GSO2. Comparison of TRFLP profiles from this mixing zone station and the Western Gyre (a station not affected by the Bosporus Plume indicate the greatest relative abundance of Sulfurimonas and Arcobacter at the appropriate depths at the mixing zone station. The autotrophic gammaproteobacterium BS-GSO2 correlated with ammonium fluxes rather than with sulfide fluxes and the maximum in SUP05 peak height was shallower than the depths where autotrophic denitrification was detected. Notably, anammox activity was not detected at the mixing zone station, though low levels of DNA from the anammox bacteria Candidatus Scalindua were present. These results provide evidence for a modified ecosystem with different N2 production pathways in the southwest coastal region compared to that found in the rest of the Black Sea. Moreover, the same Sulfurimonas phylotype (BS139 was previously detected on >30 μm particles in the suboxic zone of the Western Gyre along with DNA of potential sulfate reducers, so it is possible that particle-attached autotrophic denitrification may be an overlooked N2 production pathway in the central Black Sea as well.

  17. Development of biological platform for the autotrophic production of biofuels

    Science.gov (United States)

    Khan, Nymul

    of the current status of metabolic engineering of chemolithoautotrophs is carried out in order to identify the challenges and likely routes to overcome them. This is presented in Chapter 3 of this dissertation. The initial metabolic engineering and bioreactor studies was carried out using a number of gene-constructs on R. capsulatus and R. eutropha. The gene-constructs consisted of Plac promoter followed by the triterpene synthase genes (SS or BS) and other upstream genes. A comparison of the production of triterpenes were done in the different growth modes that R. capsulatus was capable of growing---aerobic heterotrophic, anaerobic photoheterotrophic and aerobic chemoautotrophic. Autotrophic productivity could likely be improved much further by increasing the available mass-transfer of the reactor. These efforts are presented in Chapter 4 of this dissertation. (Abstract shortened by UMI.).

  18. Lactate dehydrogenase from autotrophic and heterotrophic cells of the marine diatom Cylindrotheca fusiformis Reimann & Lewin.

    Science.gov (United States)

    Darley, W M; Smiley, R H

    1976-10-01

    Cultures of Cylindrotheca furisormis grown either autotrohpically or heterotrophically on lactate contained significant amounts of NAD-dependent L(+)-lactate dehydrogenase (EC 1.1.1.27). Polyacylamide gel electrophoresis of crude enzyme extracts revealed a single band which was indistinguishable between autotrohpic and heterotrohpic cells. The Km for lactate of partially purified preparations was lower under heterotrophic conditions. The specific activity in crude extracts was higher under autotrophic than heterotrophic conditions; it dropped precipitously when autotrophic cells were transferred to the dark, increasing again only in the presence of lactate. These and related observations suggest that this enzyme has at most only a minor role in the assimilation of lactate during heterotrophic growth on lactate. PMID:184899

  19. Autotrophic microbe metagenomes and metabolic pathways differentiate adjacent red sea brine pools

    KAUST Repository

    Wang, Yong

    2013-04-29

    In the Red Sea, two neighboring deep-sea brine pools, Atlantis II and Discovery, have been studied extensively, and the results have shown that the temperature and concentrations of metal and methane in Atlantis II have increased over the past decades. Therefore, we investigated changes in the microbial community and metabolic pathways. Here, we compared the metagenomes of the two pools to each other and to those of deep-sea water samples. Archaea were generally absent in the Atlantis II metagenome; Bacteria in the metagenome were typically heterotrophic and depended on aromatic compounds and other extracellular organic carbon compounds as indicated by enrichment of the related metabolic pathways. In contrast, autotrophic Archaea capable of CO2 fixation and methane oxidation were identified in Discovery but not in Atlantis II. Our results suggest that hydrothermal conditions and metal precipitation in the Atlantis II pool have resulted in elimination of the autotrophic community and methanogens.

  20. Management of microbial community composition, architecture and performance in autotrophic nitrogen removing bioreactors through aeration regimes

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem

    Completely autotrophic nitrogen removal from nitrogen-rich wastewaters through the nitritation -plus- anaerobic ammonium oxidation processes can greatly reduce operational energy costs compared to traditional nitrogen removal processes. The footprint can be further reduced by process intensificat......Completely autotrophic nitrogen removal from nitrogen-rich wastewaters through the nitritation -plus- anaerobic ammonium oxidation processes can greatly reduce operational energy costs compared to traditional nitrogen removal processes. The footprint can be further reduced by process...... some of the collateral impacts could be isolated, increasing process understanding. It was demonstrated that aeration strategy can be used as a powerful tool to manipulate the microbial community composition, its architecture and reactor performance. We suggest operation via intermittent aeration with...

  1. Autotrophic and heterotrophic food sources of copepods in the Scheldt estuary as traced by stable C and N isotopes

    OpenAIRE

    L. De Brabandere

    2005-01-01

    Estuaries draining densely populated watersheds experience significant anthropogenic pressure and sustain large autotrophic and heterotrophic production owing to an increased input of nutrients and organic matter. Polluted estuaries are often net heterotrophic systems. Our objective was to study the relative contributionof autotrophic and heterotrophic food webs in sustaining the high productivity of pelagic estuarine ecosystems along the estuarine gradient of the Scheldt estuary. We concentr...

  2. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    OpenAIRE

    ChristineSharp; MatthewStott

    2012-01-01

    Genomic analysis of the methanotrophic verrucomicrobium “Methylacidiphilum infernorum” strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo), ‘universal’ pmoA polymerase chain reaction (PCR) primers do not target these bacteria. Unlike proteobacterial methanotrophs, “Methylacidiphilum” fixes carbon autotrophically...

  3. Detection of autotrophic verrucomicrobial methanotrophs in a geothermal environment using stable isotope probing

    OpenAIRE

    Sharp, Christine E; Stott, Matthew B.; Dunfield, Peter F.

    2012-01-01

    Genomic analysis of the methanotrophic verrucomicrobium “Methylacidiphilum infernorum” strain V4 has shown that most pathways conferring its methanotrophic lifestyle are similar to those found in proteobacterial methanotrophs. However, due to the large sequence divergence of its methane monooxygenase-encoding genes (pmo), “universal” pmoA polymerase chain reaction (PCR) primers do not target these bacteria. Unlike proteobacterial methanotrophs, “Methylacidiphilum” fixes carbon autotrophically...

  4. Expression of Heterogenous Arsenic Resistance Genes in the Obligately Autotrophic Biomining Bacterium Thiobacillus ferrooxidans.

    Science.gov (United States)

    Peng, J B; Yan, W M; Bao, X Z

    1994-07-01

    Two arsenic-resistant plasmids were constructed and introduced into Thiobacillus ferrooxidans strains by conjugation. The plasmids with the replicon of wide-host-range plasmid RSF1010 were stable in T. ferrooxidans. The arsenic resistance genes originating from the heterotroph were expressed in this obligately autotrophic bacterium, but the promoter derived from T. ferrooxidans showed no special function in its original host. PMID:16349341

  5. Autotrophic Ammonia-Oxidizing Bacteria Contribute Minimally to Nitrification in a Nitrogen-Impacted Forested Ecosystem

    OpenAIRE

    Jordan, F L; Cantera, JJL; Fenn, M E; Stein, L.Y.

    2005-01-01

    Deposition rates of atmospheric nitrogenous pollutants to forests in the San Bernardino Mountains range east of Los Angeles, California, are the highest reported in North America. Acidic soils from the west end of the range are N-saturated and have elevated rates of N-mineralization, nitrification, and nitrate leaching. We assessed the impact of this heavy nitrogen load on autotrophic ammonia-oxidizing communities by investigating their composition, abundance, and activity. Analysis of 177 cl...

  6. Nitrogen removal by autotrophic ammonium oxidizing bacteria enrichment under anaerobic conditions

    OpenAIRE

    Pongsak (Lek) Noophan; Chalermraj Wantawin; Siriporn Sripiboon; Sanya Sirivitayapakorn

    2008-01-01

    Sludge from an anoxic tank at the centralized wastewater treatment plant, Nong Khaem, Bangkok, Thailand, was inoculatedin an anaerobic sequencing batch reactor (ASBR). The optimal compositions and operating conditions of the stock of autotrophic ammonium oxidizing bacteria medium were determined. The process of oxidizing ammonium with bacteria under anaerobic conditions is often referred to as the Anammox process (NO2- to N2 gas, using NH4+ as the electron donor and NO2- as the electron accep...

  7. Modeling, Experimentation, and Control of Autotrophic Nitrogen Removal in Granular Sludge Systems

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine

    is convenient for treating anaerobic digester liquor, landfill leachate, or special industrial wastewaters, because costs related to the need for aeration and carbon addition are lowered by 60% and 100%, respectively, compared to conventional nitrification denitrification treatment. Energy and......Complete autotrophic nitrogen removal (CANR) is a novel process that can increase the treatment capacity for wastewaters containing high concentrations of nitrogen and low organic carbon to nitrogen ratios, through an increase of the volumetric removal rate by approximately five times. This process...

  8. Partitioning Longleaf Pine Soil Respiration into Its Heterotrophic and Autotrophic Components through Root Exclusion

    OpenAIRE

    Althea A. ArchMiller; Lisa J. Samuelson

    2016-01-01

    Rapid and accurate estimations of the heterotrophic and autotrophic components of total soil respiration (Rs) are important for calculating forest carbon budgets and for understanding carbon dynamics associated with natural and management-related disturbances. The objective of this study was to use deep (60 cm) root exclusion tubes and paired control (i.e., no root exclusion) collars to estimate heterotrophic respiration (Rh) and Rs, respectively, in three 26-year-old longleaf pine (Pinus pal...

  9. Fate of 14C-labeled microbial products derived from nitrifying bacteria in autotrophic nitrifying biofilms

    OpenAIRE

    Okabe, Satoshi; Kindaichi, Tomonori; Ito, Tsukasa

    2005-01-01

    The cross-feeding of microbial products derived from 14C-labeled nitrifying bacteria to heterotrophic bacteria coexisting in an autotrophic nitrifying biofilm was quantitatively analyzed by using microautoradiography combined with fluorescence in situ hybridization (MAR-FISH). After only nitrifying bacteria were labeled with [14C] bicarbonate, biofilm samples were incubated with and without NH4+ as a sole energy source for 10 days. The transfer of 14C originally incorporated into nitrifying b...

  10. The abundance and diversity of ammonia-oxidizing bacteria in activated sludge under autotrophic domestication.

    Science.gov (United States)

    Li, Qiang; Ma, Chao; Sun, Shifang; Xie, Hui; Zhang, Wei; Feng, Jun; Song, Cunjiang

    2013-04-01

    Ammonia-oxidizing bacteria (AOB) play a key role in nitrogen-removal wastewater treatment plants (WWTPs) as they can transform ammonia into nitrite. AOB can be enriched in activated sludge through autotrophic domestication although they are difficult to be isolated. In this study, autotrophic domestication was carried out in a lab-scale sequencing-batch-reactor (SBR) system with two activated sludge samples. The ammonia removal capacity of the sludge samples increased during the domestication, and pH exhibited a negative correlation with the ammonia removal amount, which indicated that it was one important factor of microbial ammonia oxidation. The count of AOB, measured by the most probable number (MPN) method, increased significantly during autotrophic domestication as ammonia oxidation efficiency was enhanced. We investigated the changes in the community structure of AOB before and after domestication by amoA clone library and T-RFLP profile. It showed that AOB had been successfully enriched and the community structure significantly shifted during the domestication. Two groups of AOB were found in sludge samples: Nitrosomonas-like group remained predominant all the time and Nitrosospira-like group changed obviously. Simultaneously, the total heterotrophic bacteria were investigated by MPN and Biolog assay. The metabolic diversity of heterotrophs had changed minutely, although the count of them decreased significantly and lost superiority of microbial communities in the sludge. PMID:24620598

  11. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Science.gov (United States)

    Veuger, B.; Pitcher, A.; Schouten, S.; Sinninghe Damsté, J. S.; Middelburg, J. J.

    2013-03-01

    Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC (dissolved inorganic carbon) in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) in combination with compound-specific stable isotope (13C) analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41-221 nmol N L-1 h-1). Ammonium assimilation was always substantially lower than nitrification - with nitrification on average contributing 89% (range 73-97%) to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27-95 %). The inhibitor-sensitive 13C-PLFA (phospholipid-derived fatty acid) pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase)). These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance measurements only, in order to

  12. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Directory of Open Access Journals (Sweden)

    B. Veuger

    2013-03-01

    Full Text Available Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC (dissolved inorganic carbon in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate in combination with compound-specific stable isotope (13C analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N L−1 h−1. Ammonium assimilation was always substantially lower than nitrification – with nitrification on average contributing 89% (range 73–97% to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95 %. The inhibitor-sensitive 13C-PLFA (phospholipid-derived fatty acid pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance

  13. Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea

    Directory of Open Access Journals (Sweden)

    B. Veuger

    2012-11-01

    Full Text Available Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate in combination with compound-specific stable isotope (13C analysis of bacterial- and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N l−1h−1. Ammonium assimilation was always substantially lower than nitrification with nitrification on average contributing 89% (range 73–97% to total ammonium consumption.

    13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95%. The inhibitor-sensitive 13C-PLFA pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. Cell-specific 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance

  14. Autotrophic and heterotrophic denitrification for simultaneous removal of nitrogen, sulfur and organic matter.

    Science.gov (United States)

    Guerrero, Lorna; Aguirre, Juan P; Muñoz, Maria A; Barahona, Andrea; Huiliñir, Cesar; Montalvo, Silvio; Borja, Rafael

    2016-07-01

    The aim of this investigation was to assess the startup and operation of a laboratory-scale hybrid UASB-Anaerobic Filter Reactor (UASFB) of 1 L volume, kept at 30°C, in order to carry out a simultaneous autotrophic and heterotrophic denitrification process. First, the heterotrophic and autotrophic populations were separately enriched, with specific cultures and subsequently the UASFB was inoculated with 2 g L(-1) of volatile suspended solids (VSS), with a ratio of 1.5:1 (autotrophs: heterotrophs). The influent or synthetic wastewater used was composed of: Na2S2O3·5H2O, CH3COOK, NaNO3, NaHCO3, K2HPO4, NH4Cl and saline solution. The concentrations varied depending on the organic loading rate (OLR), nitrogen loading rate (NLR) and sulfur loading rate (SLR) applied. In the UASFB reactor, two experimental conditions were tested and assessed: (i) COD/N ratio of 3.6 and SLR of 0.75 kg S m(-3) d(-1); and (ii) COD/N ratio of 5.8 and SLR of 0.25 kg S m(-3) d(-1). The results obtained demonstrated that an inoculum coming from an anaerobic reactor was able to carry out the process, obtaining a maximum nitrate removal of 85.3% in the first stage of operation and 99.5% in the second stage. The recovery of sulfur in form of sulfate in the effluent did not present a tendency to stabilize during the measured time, with a maximum thiosulfate removal of 32.5%, when the SLR was lowered to 0.25 kg S m(-3) d(-1). The maximum organic matter elimination, measured as COD, was 75.8%, which indicates the relatively good performance and behavior of the heterotrophic microorganisms. PMID:27093220

  15. Enhanced start-up of anaerobic facultatively autotrophic biocathodes in bioelectrochemical systems

    KAUST Repository

    Zaybak, Zehra

    2013-12-01

    Biocathodes in bioelectrochemical systems (BESs) can be used to convert CO2 into diverse organic compounds through a process called microbial electrosynthesis. Unfortunately, start-up of anaerobic biocathodes in BESs is a difficult and time consuming process. Here, a pre-enrichment method was developed to improve start-up of anaerobic facultatively autotrophic biocathodes capable of using cathodes as the electron donor (electrotrophs) and CO2 as the electron acceptor. Anaerobic enrichment of bacteria from freshwater bog sediment samples was first performed in batch cultures fed with glucose and then used to inoculate BES cathode chambers set at -0.4V (versus a standard hydrogen electrode; SHE). After two weeks of heterotrophic operation of BESs, CO2 was provided as the sole electron acceptor and carbon source. Consumption of electrons from cathodes increased gradually and was sustained for about two months in concert with a significant decrease in cathode chamber headspace CO2. The maximum current density consumed was -34±4mA/m2. Biosynthesis resulted in organic compounds that included butanol, ethanol, acetate, propionate, butyrate, and hydrogen gas. Bacterial community analyses based on 16S rRNA gene clone libraries revealed Trichococcus palustris DSM 9172 (99% sequence identity) as the prevailing species in biocathode communities, followed by Oscillibacter sp. and Clostridium sp. Isolates from autotrophic cultivation were most closely related to Clostridium propionicum (99% sequence identity; ZZ16), Clostridium celerecrescens (98-99%; ZZ22, ZZ23), Desulfotomaculum sp. (97%; ZZ21), and Tissierella sp. (98%; ZZ25). This pre-enrichment procedure enables simplified start-up of anaerobic biocathodes for applications such as electrofuel production by facultatively autotrophic electrotrophs. © 2013 Elsevier B.V.

  16. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor

    International Nuclear Information System (INIS)

    Highlights: → Intensified biofilm-electrode reactor using cooperative denitrification is developed. → IBER combines heterotrophic and autotrophic denitrification. → CO2 formed by heterotrophic denitrification is used by autotrophic bacteria. → Optimum running conditions are C/N = 0.75, HRT = 8 h, and I = 40 mA. → A novel degradation mechanism for cooperating denitrification process is proposed. - Abstract: An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO3-N50 mg L-1) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8 h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO3-N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO2 produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate.

  17. Nitrate removal from groundwater by cooperating heterotrophic with autotrophic denitrification in a biofilm-electrode reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yingxin [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan); Feng, Chuanping, E-mail: fengchuangping@gmail.com [School of Water Resources and Environment, China University of Geosciences, Beijing 100083 (China); Wang, Qinghong; Yang, Yingnan; Zhang, Zhenya; Sugiura, Norio [Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 3058572 (Japan)

    2011-09-15

    Highlights: {yields} Intensified biofilm-electrode reactor using cooperative denitrification is developed. {yields} IBER combines heterotrophic and autotrophic denitrification. {yields} CO{sub 2} formed by heterotrophic denitrification is used by autotrophic bacteria. {yields} Optimum running conditions are C/N = 0.75, HRT = 8 h, and I = 40 mA. {yields} A novel degradation mechanism for cooperating denitrification process is proposed. - Abstract: An intensified biofilm-electrode reactor (IBER) combining heterotrophic and autotrophic denitrification was developed for treatment of nitrate contaminated groundwater. The reactor was evaluated with synthetic groundwater (NO{sub 3}{sup -}N50 mg L{sup -1}) under different hydraulic retention times (HRTs), carbon to nitrogen ratios (C/N) and electric currents (I). The experimental results demonstrate that high nitrate and nitrite removal efficiency (100%) were achieved at C/N = 1, HRT = 8 h, and I = 10 mA. C/N ratios were reduced from 1 to 0.5 and the applied electric current was changed from 10 to 100 mA, showing that the optimum running condition was C/N = 0.75 and I = 40 mA, under which over 97% of NO{sub 3}{sup -}N was removed and organic carbon (methanol) was completely consumed in treated water. Simultaneously, the denitrification mechanism in this system was analyzed through pH variation in effluent. The CO{sub 2} produced from the anode acted as a good pH buffer, automatically controlling pH in the reaction zone. The intensified biofilm-electrode reactor developed in the study was effective for the treatment of groundwater polluted by nitrate.

  18. Bio-sequestration of CO2 Using Carbonic Anhydrase in situ Encapsulated Inside Electrospun Hollow Fibers%静电纺丝制备中空纤维原位固定化碳酸酐酶用于二氧化碳的吸收

    Institute of Scientific and Technical Information of China (English)

    崔建东; 李莹; 姬晓元; 边红杰; 张羽飞; 苏志国; 马光辉; 张松平

    2014-01-01

    Carbonic anhydrase catalyzed bio-sequestration of CO2 to form HCO-3 , followed by trapping as solid CaCO3 is one of the most promising technologies for CO2 capturing. The effects of reaction condition on the CO2 hydration using free carbonic anhydrase were systematically investigated. In order to improve the stability of the enzyme and facility its recycling, the carbonic anhydrase was in situ encapsulated inside hollow fibers via a novel co-axial electrospinning technology. Compared with the free enzyme, the immobilized carbonic an-hydrase showed much improved thermal stability and suffered much reduced inhibitory effects from cation ions, such as Cu2+ and Fe3+. After 11 reuses, the immobilized enzyme retained about 81. 9% of its original activity by comparing the amount of formed CaCO3 precipitation. In the presence of immobilized carbonic anhydrase, both calcite and vaterite CaCO3 solid were formed;while in the absence of enzyme or with free carbonic anhy-drase, only calcite CaCO3 was observed.%考察了游离碳酸酐酶吸收CO2水合体系反应条件,并通过同轴共纺静电纺丝技术制备出中空结构纤维,实现了碳酸酐酶在中空纤维中的原位包埋,提高了酶的稳定性并便于回收和重复利用.实验结果表明,固定化碳酸酐酶的热稳定性显著增强,受Cu2+和Fe3+等金属离子的抑制作用大幅度降低.连续使用11次后所生成的CaCO3沉淀量仍能达到首次使用的81.9%.固定化酶体系生成的CaCO3沉淀包括方解石型和球文石型2种晶形,而无酶和加入游离碳酸酐酶的反应体系则主要生成方解石型CaCO3沉淀.

  19. Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

    Directory of Open Access Journals (Sweden)

    W. Koeve

    2010-08-01

    Full Text Available The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (ΔCO2:ΔN2, varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of ΔCO2:ΔN2 can be found. However, accounting for concomitant diffusive fluxes of CO2, the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic

  20. Redox stratified biofilms to support completely autotrophic nitrogen removal: Principles and results

    DEFF Research Database (Denmark)

    Pellicer i Nàcher, Carles; Smets, Barth F.

    biofilm structure with aerobic ammonium oxidizing bacteria dominating the areas of the biofilm closer to the membrane surface while anaerobic oxidizing bacteria populated mainly the outer biofilm region. The biofilm was approximately 500 m thick and featured both aerobic and anaerobic ammonium oxidizing...... the outgrowth of nitrite oxidizing bacteria communities. Autotrophic nitrogen removal is already revealing itself as a cheap alternative to treat concentrated nitrogen streams. However, we believe that this concept can be taken a step further in MABRs and become an even more cost-effective, compact...

  1. Performance of an autotrophic nitrogen removing reactor: Diagnosis through fuzzy logic

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mauricio Iglesias, Miguel; Mutlu, Ayten Gizem; Gernaey, Krist; Smets, Barth F.; Sin, Gürkan

    Autotrophic nitrogen removal through nitritation-anammox in one stage SBRs is an energy and cost efficient alternative to conventional treatment methods. Intensification of an already complex biological system challenges our ability to observe, understand, diagnose, and control the system. A fuzzy...... logic diagnosis tool was developed, utilizing stoichiometric and concentration ratio measurements and removal efficiencies, along with rules derived from process knowledge. The tool could accurately determine the overall performance of the system and can therefore serve as a powerful tool to provide...

  2. The sulfocyanic theory on the origin of life: towards a critical reappraisal of an autotrophic theory

    Science.gov (United States)

    Perezgasga, L.; Silva, E.; Lazcano, A.; Negrin-Mendoza, A.

    2003-10-01

    In the early 1930s, Alfonso L. Herrera proposed his so-called sulfocyanic theory on the origin of life, an autotrophic proposal on the first living beings according to which NH4SCN and H2CO acted as raw materials for the synthesis of bio-organic compounds inside primordial photosynthetic protoplasmic structures. Although the work of Herrera is frequently cited in historical analysis of the development of the origin of life studies, very little attention has been given to the chemical significance of the reactions he published. In this paper we report the results of our search for amino acids obtained from a reactive mixture used by Herrera from 1933 onwards. Chromatograms using the high-pressure liquid chromatography (HPLC) technique suggest the presence of several amino acids, the total yield being 2% of the initial thiocyanate used. Preliminary identification based on HPLC retention times suggests the presence of glycine, alanine, cysteine and methionine. Alanine was the most abundant amino acid in all samples of fractionated material analysed. Although the starting materials used by Herrera were determined by his autotrophic hypothesis on the origin of cells, our results show that his experiments may provide insights into the abiotic synthesis of sulfur-containing amino acids within the framework of a heterotrophic emergence of life.

  3. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions.

    Science.gov (United States)

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ(15)NNO3), carbon in dissolved inorganic carbon (δ(13)CDIC), and sulfur in sulfate (δ(34)SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ(13)CDIC (from -7.7‰ to -12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was -4.7‰), suggesting the contribution of C of trisodium citrate (δ(13)C=-12.4‰). No SO4(2-) and δ(34)SSO4 changes were observed. In the AD experiment, clear fractionation of δ(13)CDIC during DIC consumption (εC=-7.8‰) and δ(34)SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN=-12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field. PMID:26529303

  4. High CO2 subsurface environment enriches for novel microbial lineages capable of autotrophic carbon fixation

    Science.gov (United States)

    Probst, A. J.; Jerett, J.; Castelle, C. J.; Thomas, B. C.; Sharon, I.; Brown, C. T.; Anantharaman, K.; Emerson, J. B.; Hernsdorf, A. W.; Amano, Y.; Suzuki, Y.; Tringe, S. G.; Woyke, T.; Banfield, J. F.

    2015-12-01

    Subsurface environments span the planet but remain little understood from the perspective of the capacity of the resident organisms to fix CO2. Here we investigated the autotrophic capacity of microbial communities in range of a high-CO2 subsurface environments via analysis of 250 near-complete microbial genomes (151 of them from distinct species) that represent the most abundant organisms over a subsurface depth transect. More than one third of the genomes belonged to the so-called candidate phyla radiation (CPR), which have limited metabolic capabilities. Approximately 30% of the community members are autotrophs that comprise 70% of the microbiome with metabolism likely supported by sulfur and nitrogen respiration. Of the carbon fixation pathways, the Calvin Benson Basham Cycle was most common, but the Wood-Ljungdhal pathway was present in the greatest phylogenetic diversity of organisms. Unexpectedly, one organism from a novel phylum sibling to the CPR is predicted to fix carbon by the reverse TCA cycle. The genome of the most abundant organism, an archaeon designated "Candidatus Altiarchaeum hamiconexum", was also found in subsurface samples from other continents including Europe and Asia. The archaeon was proven to be a carbon fixer using a novel reductive acetyl-CoA pathway. These results provide evidence that carbon dioxide is the major carbon source in these environments and suggest that autotrophy in the subsurface represents a substantial carbon dioxide sink affecting the global carbon cycle.

  5. Nitrogen removal by autotrophic ammonium oxidizing bacteria enrichment under anaerobic conditions

    Directory of Open Access Journals (Sweden)

    Pongsak (Lek Noophan

    2008-07-01

    Full Text Available Sludge from an anoxic tank at the centralized wastewater treatment plant, Nong Khaem, Bangkok, Thailand, was inoculatedin an anaerobic sequencing batch reactor (ASBR. The optimal compositions and operating conditions of the stock of autotrophic ammonium oxidizing bacteria medium were determined. The process of oxidizing ammonium with bacteria under anaerobic conditions is often referred to as the Anammox process (NO2- to N2 gas, using NH4+ as the electron donor and NO2- as the electron acceptor. The startup period for the anammox culture took more than three months. With ammoniumand nitrite concentration ratios of 1:1.38 and 1:1.6, the nitrogen conversion rate zero order. Fluorescent in situ hybridization(FISH was used to identify specific autotrophic ammonium oxidizing bacteria (Nitrosomonas spp., Candidatus Brocadia anammoxidans, and Candidatus Kuenenia stuttgartiensis. Results from this work demonstrated a shift in the species of ammonium oxidizing bacteria from Nitrosomonas spp. to Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis, with increased ammonium concentrations from 3 mM to 15 mM. Under NH4+:NO2- ratios of 1:1.38 and 1:1.6 the ammoniumoxidizing bacteria were able to remove both ammonium and nitrite simultaneously. The specific nitrogen removal rate of theanammox bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis was significantly higher than that of anaerobic ammonium oxidizing bacteria (Nitrosomonas spp.. Anaerobic ammonium oxidizing bacteria (Candidati Brocadia anammoxidans and Kuenenia stuttgartiensis are strict anaerobes.

  6. The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage.

    Science.gov (United States)

    Ma, Bin; Zhang, Shujun; Zhang, Liang; Yi, Peng; Wang, Junmin; Wang, Shuying; Peng, Yongzhen

    2011-09-01

    The feasibility of using a two-stage autotrophic nitrogen removal process to treat sewage was examined in this study. The obtained results showed that total nitrogen (TN) could be efficiently removed by 88.38% when influent TN and chemical oxygen demand (COD) were 45.87 and 44.40 mg/L, respectively. In the first stage, nitritation was instantly achieved by the bioaugmentation strategy, and can be maintained under limited oxygen condition (below 0.2mg/L). The ratio of nitrite to ammonium in the effluent of the nitritation reactor can be controlled at approximate 1.0 by adjusting aeration rate. In the second stage, anammox was realized in the upflow anaerobic sludge blanket (UASB) reactor, where the total nitrogen removal rate was 0.40 kg Nm(-3)d(-1) under limited-substrate condition. Therefore, the organic matter in sewage can be firstly concentrated in biomass which could generate biogas (energy). Then, nitrogen in sewage could be removed in a two-stage autotrophic nitrogen removal process. PMID:21719278

  7. Particulate Pyrite Autotrophic Denitrification (PPAD) for Remediation of Nitrate-contaminated Groundwater

    Science.gov (United States)

    Tong, S.; Rodriguez-Gonzalez, L. C.; Henderson, M.; Feng, C.; Ergas, S. J.

    2015-12-01

    The rapid movement of human civilization towards urbanization, industrialization, and increased agricultural activities has introduced a large amount of nitrate into groundwater. Nitrate is a toxic substance discharged from groundwater to rivers and leads to decreased dissolved oxygen and eutrophication. For this experiment, an electron donor is needed to convert nitrate into non-toxic nitrogen gas. Pyrite is one of the most abundant minerals in the earth's crust making it an ideal candidate as an electron donor. The overall goal of this research was to investigate the potential for pyrite to be utilized as an electron donor for autotrophic denitrification of nitrate-contaminated groundwater. Batch studies of particulate pyrite autotrophic denitrification (PPAD) of synthetic groundwater (100 mg NO3--N L-1) were set up with varying biomass concentration, pyrite dose, and pyrite particle size. Reactors were seeded with mixed liquor volatile suspended solids (VSS) from a biological nitrogen removal wastewater treatment facility. PPAD using small pyrite particles (treatment and promoted the utilization of pyrite in the field of environmental remediation.

  8. Bio-electrochemical synthesis of commodity chemicals by autotrophic acetogens utilizing CO_{2} for environmental remediation

    Indian Academy of Sciences (India)

    GUGAN JABEEN; ROBINA FAROOQ

    2016-09-01

    Bio-electrochemical synthesis (BES) is a technique in which electro-autotrophic bacteria such as Clostridiumljungdahlii utilize electric currents as an electron source from the cathode to reduce CO_{2} to extracellular, multicarbon,exquisite products through autotrophic conversion. The BES of volatile fatty acids and alcohols directly fromCO_{2} is a sustainable alternative for non-renewable, petroleum-based polymer production. This conversion ofCO_{2} implies reduction of greenhouse gas emissions. The synthesis of heptanoic acid, heptanol, hexanoic acidand hexanol, for the first time, by Clostridium ljungdahlii was a remarkable achievement of BES. In ourstudy, these microorganisms were cultivated on the cathode of a bio-electrochemical cell at −400 mV by aDC power supply at 37°C, pH 6.8, and was studied for both batch and continuous systems. Pre-enrichment ofbio-cathode enhanced the electroactivity of cells and resulted in maximizing extracellular products in lesstime. The main aim of the research was to investigate the impact of low-cost substrate CO_{2}, and the longercathode recovery range was due to bacterial reduction of CO_{2} to multicarbon chemical commodities withelectrons driven from the cathode. Reactor design was simplified for cost-effectiveness and to enhance energyefficiencies. The Columbic recovery of ethanoic acid, ethanol, ethyl butyrate, hexanoic acid, heptanoic acidand hexanol being in excess of 80% proved that BES was a remarkable technology.

  9. Bio-electrochemical synthesis of commodity chemicals by autotrophic acetogens utilizing CO2 for environmental remediation.

    Science.gov (United States)

    Jabeen, Gugan; Farooq, Robina

    2016-09-01

    Bio-electrochemical synthesis (BES) is a technique in which electro-autotrophic bacteria such as Clostridium ljungdahlii utilize electric currents as an electron source from the cathode to reduce CO2 to extracellular, multicarbon, exquisite products through autotrophic conversion. The BES of volatile fatty acids and alcohols directly from CO2 is a sustainable alternative for non-renewable, petroleum-based polymer production. This conversion of CO2 implies reduction of greenhouse gas emissions. The synthesis of heptanoic acid, heptanol, hexanoic acid and hexanol, for the first time, by Clostridium ljungdahlii was a remarkable achievement of BES. In our study, these microorganisms were cultivated on the cathode of a bio-electrochemical cell at -400 mV by a DC power supply at 37 degree Centrigrade, pH 6.8, and was studied for both batch and continuous systems. Pre-enrichment of bio-cathode enhanced the electroactivity of cells and resulted in maximizing extracellular products in less time. The main aim of the research was to investigate the impact of low-cost substrate CO2, and the longer cathode recovery range was due to bacterial reduction of CO2 to multicarbon chemical commodities with electrons driven from the cathode. Reactor design was simplified for cost-effectiveness and to enhance energy efficiencies. The Columbic recovery of ethanoic acid, ethanol, ethyl butyrate, hexanoic acid, heptanoic acid and hexanol being in excess of 80 percent proved that BES was a remarkable technology. PMID:27581929

  10. Heterotrophic and Autotrophic Microbial Populations in Cold Perennial Springs of the High Arctic ▿ †

    Science.gov (United States)

    Perreault, Nancy N.; Greer, Charles W.; Andersen, Dale T.; Tille, Stefanie; Lacrampe-Couloume, Georges; Lollar, Barbara Sherwood; Whyte, Lyle G.

    2008-01-01

    The saline springs of Gypsum Hill in the Canadian high Arctic are a rare example of cold springs originating from deep groundwater and rising to the surface through thick permafrost. The heterotrophic bacteria and autotrophic sulfur-oxidizing bacteria (up to 40% of the total microbial community) isolated from the spring waters and sediments were classified into four phyla (Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria) based on 16S rRNA gene analysis; heterotrophic isolates were primarily psychrotolerant, salt-tolerant, facultative anaerobes. Some of the isolates contained genes for thiosulfate oxidation (soxB) and anoxygenic photosynthesis (pufM), possibly enabling the strains to better compete in these sulfur-rich environments subject to long periods of illumination in the Arctic summer. Although leucine uptake by the spring water microbial community was low, CO2 uptake was relatively high under dark incubation, reinforcing the idea that primary production by chemoautotrophs is an important process in the springs. The small amounts of hydrocarbons in gases exsolving from the springs (0.38 to 0.51% CH4) were compositionally and isotopically consistent with microbial methanogenesis and possible methanotrophy. Anaerobic heterotrophic sulfur oxidation and aerobic autotrophic sulfur oxidation activities were demonstrated in sediment slurries. Overall, our results describe an active microbial community capable of sustainability in an extreme environment that experiences prolonged periods of continuous light or darkness, low temperatures, and moderate salinity, where life seems to rely on chemolithoautotrophy. PMID:18805995

  11. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions

    Science.gov (United States)

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ15NNO3), carbon in dissolved inorganic carbon (δ13CDIC), and sulfur in sulfate (δ34SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ13CDIC (from - 7.7‰ to - 12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was - 4.7‰), suggesting the contribution of C of trisodium citrate (δ13C = - 12.4‰). No SO42 - and δ34SSO4 changes were observed. In the AD experiment, clear fractionation of δ13CDIC during DIC consumption (εC = - 7.8‰) and δ34SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN = - 12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field.

  12. Sulfide removal by simultaneous autotrophic and heterotrophic desulfurization-denitrification process

    International Nuclear Information System (INIS)

    An anaerobic attached-growth bioreactor (AAGBR) of 3.52 L was operated for 510 days to treat sulfide-laden organic wastewater where nitrate and nitrite were introduced as electron acceptors. When the influent sulfide was kept at 200 mg S2--S/L and organic carbon was increased from 20 to 33.6 mg C/L, and the hydraulic retention time decreased from 41.4 to 2.67 h, the removal rates of sulfide and organic carbon reached 99.9% and 91.8% at the loading rates of 1800 mg S2--S/(L d) and 302.4 mg C/(L d), respectively. Simultaneously, the introduced electron acceptors of nitrate and nitrite were, respectively, removed by 99.9% and 99.9% at the loading rates of 472.5 mg NO3--N/(L d) and 180 mg NO2--N/(L d). Inside the AAGBR, both autotrophic and heterotrophic denitrification processes were noted to take place. When the influent organic carbon was increased from 20 to 33.6 mg C/L, the nitrate and nitrite consumed for heterotrophic denitrification accounted for 27.3% and 48.5%, respectively. This simultaneous autotrophic and heterotrophic desulfurization-denitrification process has provided a demonstration of the possibility to eliminate sulfide and organic carbon with the presence of nitrate and nitrite

  13. UV resonance Raman sensing of pharmaceutical drugs in hollow fibers

    Science.gov (United States)

    Yan, D.; Popp, J.; Frosch, T.

    2014-05-01

    We report about the experimental combination of UV resonance Raman sensing (UV-RRS) and fiber enhanced Raman sensing (FERS) on pharmaceuticals. The results show that the chemical sensitivity is highly improved and at the same time the sample volume is reduced compared to conventional measurements. A hundreds-fold improvement of the limit of detection (LOD) has been achieved with the combination of resonance Raman enhancement and fiber enhancement. The enhanced Raman signal has a reliable linear relationship with the concentration of the analyte, and therefore shows great potential for quantitative analysis of pharmaceuticals.

  14. Hollow fiber contractors for simultaneous SOx/NOx removal

    International Nuclear Information System (INIS)

    Control of SOx and NOx emissions from coal-fired utility and industrial boilers is a topic of growing national and international importance. Whereas a host of commercial and semicommercial processes exist, increasingly stringent emission standards mandate that processes be low cost, highly efficient, and, ideally, produce marketable byproducts. Although a wide range of site-specific economic factors dictate the best choice of SOx and NOx control, removal of SO2 by wet limestone scrubbing and removal of NOx by selective catalytic reduction (SCR) are regarded as the best commercialized technologies for this application. A typical wet limestone plant requires approximately $100 to $120 of capital investment per kilowatt of electric power generating capacity and has power and miscellaneous operating costs in the range of 5 to 6 mils per kilowatt hour (kWh). The SCR process requires approximately $70 to $100 of capital investment per kilowatt of electric power generating capacity. Its operating costs, including ammonia consumption, is in the range of 1.8 to 2.2 mils per kWh. These costs can add approximately 20% to the final cost of generated electricity, a significant burden on rate payers

  15. Polysulfone hollow fiber gas separation membranes filled with submicron particles.

    Science.gov (United States)

    Bhardwaj, V; Macintosh, A; Sharpe, I D; Gordeyev, S A; Shilton, S J

    2003-03-01

    Three different fillers, carbon black (CB), vapor grown carbon fibers (VGCF), and TiO(2), were incorporated into polysulfone spinning solutions with the intention of producing highly selective membranes with enhanced mechanical strength. The effect of filler presence on gas permeation characteristics, mechanical strength (bursting pressure), and morphology was investigated and compared to unfilled membranes. As well as studying filler types, the influence of CB filler concentration on membrane performance was also examined. For all filler types (at a concentration of 5%w/w), the pressure-normalized flux of O(2), N(2), and CH(4) was greater in the composite than in the unfilled membranes. The CO(2) pressure-normalized flux was only greater in the TiO(2) composite membranes. For CB and VGCF, the CO(2) pressure-normalized flux was reduced compared with unfilled membranes. Three CB concentrations were investigated (2, 5, and 10%w/w). For O(2), N(2), and CH(4), pressure-normalized flux peaked at 5%w/w CB. CO(2) exhibited the opposite trend, showing a minimum pressure-normalized flux at 5%w/w. Considering O(2)/N(2) and CO(2)/CH(4) gas pairs and the various filled membrane categories, only the O(2)/N(2) selectivity of the 2%w/w CB filled membranes was higher than that of the unfilled fibers-all other selectivities were lower. In terms of CB concentration, selectivity was a minimum at the intermediate concentration of 5%w/w. All the filled membrane types exhibited greater mechanical strength (bursting pressure) than unfilled fibers apart from the 5%w/w VGCF composites. The 2%w/w CB composites were the strongest. Electron microscopy showed no visible differences in general morphology between the various filled and unfilled membranes. PMID:12783827

  16. Interaction between hepatocytes and collagen gel in hollow fibers

    OpenAIRE

    Dai, Jing; Zhang, Guo-Liang; Meng, Qin

    2009-01-01

    Gel entrapment culture of primary mammalian cells within collagen gel is one important configuration for construction of bioartificial organ as well as in vitro model for predicting drug situation in vivo. Gel contraction in entrapment culture, resulting from cell-mediated reorganization of the extracellular matrix, was commonly used to estimate cell viability. However, the exact influence of gel contraction on cell activities has rarely been addressed. This paper investigated the gel contrac...

  17. Modeling of Multicomponent Mixture Separation Processes Using Hollow fiber Membrane

    International Nuclear Information System (INIS)

    So far, most of research activities on modeling of membrane separation processes have been focused on binary feed mixture. But, in actual separation operations, binary feed is hard to find and most separation processes involve multicomponent feed mixture. In this work models for membrane separation processes treating multicomponent feed mixture are developed. Various model types are investigated and validity of proposed models are analysed based on experimental data obtained using hollowfiber membranes. The proposed separation models show quick convergence and exhibit good tracking performance

  18. Modeling of Multicomponent Mixture Separation Processes Using Hollow fiber Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sin-Ah; Kim, Jin-Kuk; Lee, Young Moo; Yeo, Yeong-Koo [Hanyang University, Seoul (Korea, Republic of)

    2015-02-15

    So far, most of research activities on modeling of membrane separation processes have been focused on binary feed mixture. But, in actual separation operations, binary feed is hard to find and most separation processes involve multicomponent feed mixture. In this work models for membrane separation processes treating multicomponent feed mixture are developed. Various model types are investigated and validity of proposed models are analysed based on experimental data obtained using hollowfiber membranes. The proposed separation models show quick convergence and exhibit good tracking performance.

  19. An operation protocol for facilitating start-up of single-stage autotrophic nitrogen removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, A. Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan; Smets, Barth F.

    2012-01-01

    Start-up and operation of single-stage nitritation/anammox reactor employing complete autotrophic nitrogen can be difficult. Keeping the performance criteria and monitoring the microbial community composition may not be easy or fast enough to take action on time. In this study, a control strategy...

  20. Coniochaeta ligniaria: antifungal activity of the cryptic endophytic fungus associated with autotrophic cultures of the medicinal plant Smallanthus sonchifolius (Asteraceae)

    Science.gov (United States)

    Few studies have addressed the presence and bioactivity of endophytic fungi living in plantlets growing under in vitro conditions. We isolated a fungus UM 109 from autotrophic cultures of the medicinal plant Smallanthus sonchifolius (yacon). The species was identified as Coniochaeta ligniaria using ...