Functionalized nanoparticle interactions with polymeric membranes.

Science.gov (United States)

Ladner, D A; Steele, M; Weir, A; Hristovski, K; Westerhoff, P

2012-04-15

A series of experiments was performed to measure the retention of a class of functionalized nanoparticles (NPs) on porous (microfiltration and ultrafiltration) membranes. The findings impact engineered water and wastewater treatment using membrane technology, characterization and analytical schemes for NP detection, and the use of NPs in waste treatment scenarios. The NPs studied were composed of silver, titanium dioxide, and gold; had organic coatings to yield either positive or negative surface charge; and were between 2 and 10nm in diameter. NP solutions were applied to polymeric membranes composed of different materials and pore sizes (ranging from ≈ 2 nm [3 kDa molecular weight cutoff] to 0.2 μm). Greater than 99% rejection was observed of positively charged NPs by negatively charged membranes even though pore diameters were up to 20 times the NP diameter; thus, sorption caused rejection. Negatively charged NPs were less well rejected, but behavior was dependent not only on surface functionality but on NP core material (Ag, TiO(2), or Au). NP rejection depended more upon NP properties than membrane properties; all of the negatively charged polymeric membranes behaved similarly. The NP-membrane interaction behavior fell into four categories, which are defined and described here. Copyright © 2011 Elsevier B.V. All rights reserved.

Polymeric molecular sieve membranes via in situ cross-linking of non-porous polymer membrane templates.

Science.gov (United States)

Qiao, Zhen-An; Chai, Song-Hai; Nelson, Kimberly; Bi, Zhonghe; Chen, Jihua; Mahurin, Shannon M; Zhu, Xiang; Dai, Sheng

2014-04-16

High-performance polymeric membranes for gas separation are attractive for molecular-level separations in industrial-scale chemical, energy and environmental processes. Molecular sieving materials are widely regarded as the next-generation membranes to simultaneously achieve high permeability and selectivity. However, most polymeric molecular sieve membranes are based on a few solution-processable polymers such as polymers of intrinsic microporosity. Here we report an in situ cross-linking strategy for the preparation of polymeric molecular sieve membranes with hierarchical and tailorable porosity. These membranes demonstrate exceptional performance as molecular sieves with high gas permeabilities and selectivities for smaller gas molecules, such as carbon dioxide and oxygen, over larger molecules such as nitrogen. Hence, these membranes have potential for large-scale gas separations of commercial and environmental relevance. Moreover, this strategy could provide a possible alternative to 'classical' methods for the preparation of porous membranes and, in some cases, the only viable synthetic route towards certain membranes.

Differential natural organic matter fouling of ceramic versus polymeric ultrafiltration membranes.

Science.gov (United States)

Lee, Seung-Jin; Kim, Jae-Hong

2014-01-01

Ceramic ultrafiltration membranes has drawn increasing attention in drinking water treatment sectors as an alternative to traditional polymeric counterparts, yet only limited information has been made available about the characteristics of ceramic membrane fouling by natural organic matter. The effects of solution chemistry including ionic strength, divalent ion concentration and pH on the flux behavior were comparatively evaluated for ceramic and polymeric ultrafiltration of synthetic water containing model natural organic matter. Filtration characteristics were further probed via resistance-in-series model analysis, fouling visualization using quantum dots, batch adsorption test, contact angle measurement, solute-membrane surface adhesion force measurement, and quantitative comparison of fouling characteristics between ceramic and polymeric membranes. The results collectively suggested that the effects of solution chemistry on fouling behavior of ceramic membranes were generally similar to polymeric counterparts in terms of trends, while the extent varied significantly depending on water quality parameters. Lower fouling tendency and enhanced cleaning efficiency were observed with the ceramic membrane, further promoting the potential for ceramic membrane application to surface water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous AuIII Extraction and In Situ Formation of Polymeric Membrane-Supported Au Nanoparticles: A Sustainable Process with Application in Catalysis.

Science.gov (United States)

Mora-Tamez, Lucía; Esquivel-Peña, Vicente; Ocampo, Ana L; Rodríguez de San Miguel, Eduardo; Grande, Daniel; de Gyves, Josefina

2017-04-10

A polymeric membrane-supported catalyst with immobilized gold nanoparticles (AuNPs) was prepared through the extraction and in situ reduction of Au III salts in a one-step strategy. Polymeric inclusion membranes (PIMs) and polymeric nanoporous membranes (PNMs) were tested as different membrane-support systems. Transport experiments indicated that PIMs composed of cellulose triacetate, 2-nitrophenyloctyl ether, and an aliphatic tertiary amine (Adogen 364 or Alamine 336) were the most efficient supports for Au III extraction. The simultaneous extraction and reduction processes were proven to be the result of a synergic phenomenon in which all the membrane components were involved. Scanning electron microscopy characterization of cross-sectional samples suggested a distribution of AuNPs throughout the membrane. Transmission electron microscopy characterization of the AuNPs indicated average particle sizes of 36.7 and 2.9 nm for the PIMs and PNMs, respectively. AuNPs supported on PIMs allowed for >95.4 % reduction of a 0.05 mmol L -1 4-nitrophenol aqueous solution with 10 mmol L -1 NaBH 4 solution within 25 min. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reverse-osmosis membranes by plasma polymerization

Science.gov (United States)

Hollahan, J. R.; Wydeven, T.

1972-01-01

Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective.

Characteristics of polyimide-based composite membranes fabricated by low-temperature plasma polymerization

International Nuclear Information System (INIS)

Dung Thi Tran; Mori, Shinsuke; Suzuki, Masaaki

2008-01-01

Composite membranes were prepared by the deposition of plasma-polymerized allylamine films onto a porous polyimide substrate. The relationship between the plasma conditions and the membrane characteristics was described in terms of monomer flow rate, plasma discharge power, plasma polymerization time, and so on. Scanning electron microscope (SEM) images indicate that the thickness of the plasma polymer layer increased and the membrane skin pore size decreased gradually with the increasing of plasma polymerization time. Fourier transform infrared (FTIR) spectra demonstrate the appearance of amine groups in the plasma deposited polymer and the contact angle measurements indicate that the hydrophilicity of the membrane surfaces increased significantly after plasma polymerization. The composite membranes can reject salt from sodium chloride feed solution, and membrane separation performance depends strongly on the plasma conditions applied during the preparation of the plasma deposited polymer films

Proteins and Peptides in Biomimetic Polymeric Membranes

DEFF Research Database (Denmark)

Perez, Alfredo Gonzalez

2013-01-01

This chapter discusses recent advances and the main advantages of block copolymers for functional membrane protein reconstitution in biomimetic polymeric membranes. A rational approach to the reconstitution of membrane proteins in a functional form can be addressed by a more holistic view by using...... other kind of nonbiological amphiphilic molecules. An interesting possibility could be the use of self-assembled proteins in a lipid-free membrane mimicking the capside of some viruses. The membrane proteins that have been more actively used in combination with block copolymer membranes are gramicidin...

Surface modification of cation exchange membranes by graft polymerization of PAA-co-PANI/MWCNTs nanoparticles

International Nuclear Information System (INIS)

Nemati, Mahsa; Hosseini, Sayed Mohsen; Bagheripour, Ehsan; Madaeni, Sayed Siavash

2016-01-01

Surface modification of polyvinylchloride based heterogeneous cation exchange membrane was performed by graft polymerization of PAA and PAA-co-PANI/MWCNTs nanoparticles. The ion exchange membranes were prepared by solution casting technique. Spectra analysis confirmed graft polymerization clearly. SEM images illustrated that graft polymerization covers the membranes by simple gel network entanglement. The membrane water content was decreased by graft polymerization of PAA-co-PANI/MWCNTs nanoparticles on membrane surface. Membrane transport number and selectivity declined initially by PAA graft polymerization and then began to increase by utilizing of composite nanoparticles in modifier solution. The sodium and barium flux was improved sharply by PAA and PAAco- 0.01%wt PANI/MWCNTs graft polymerization on membrane surface and then decreased again by more increase of PANI/MWCNTs nanoparticles content ratio in modifier solution. The electrodialysis experiment results in laboratory scale showed higher dialytic rate in heavy metals removal for grafted-PAA and grafted-PAA-co-PANI/MWCNTs modified membrane compared to pristine one. Membrane areal electrical resistance was also decreased by introducing graft polymerization of PAA and PAA-co-PANI/MWCNTs NPs on membrane surface.

Cellulose acetate-based molecularly imprinted polymeric membrane for separation of vanillin and o-vanillin

OpenAIRE

Zhang,Chunjing; Zhong,Shian; Yang,Zhengpeng

2008-01-01

Cellulose acetate-based molecularly imprinted polymeric membranes were prepared using vanillin as template molecule. The microscopic structure of the resultant polymeric membranes was characterized by SEM and FTIR spectroscopy, and the selective binding properties and separation capacity of the membranes for vanillin and o-vanillin were tested with binding experiments and separate experiments, respectively. The results showed that the vanillin-imprinted polymeric membranes displayed higher bi...

Constructing Functional Ionic Membrane Surface by Electrochemically Mediated Atom Transfer Radical Polymerization

Directory of Open Access Journals (Sweden)

Fen Ran

2016-01-01

Full Text Available The sodium polyacrylate (PAANa contained polyethersulfone membrane that was fabricated by preparation of PES-NH2 via nonsolvent phase separation method, the introduction of bromine groups as active sites by grafting α-Bromoisobutyryl bromide, and surface-initiated electrochemically atom transfer radical polymerization (SI-eATRP of sodium acrylate (AANa on the surface of PES membrane. The polymerization could be controlled by reaction condition, such as monomer concentration, electric potential, polymerization time, and modifier concentration. The membrane surface was uniform when the monomer concentration was 0.9 mol/L, the electric potential was −0.12 V, the polymerization time was 8 h, and the modifier concentration was 2 wt.%. The membrane showed excellent hydrophilicity and blood compatibility. The water contact angle decreased from 84° to 68° and activated partial thromboplastin increased from 51 s to 84 s after modification of the membranes.

Surface engineering: molecularly imprinted affinity membranes by photograft polymerization

Science.gov (United States)

Matuschewski, Heike; Sergeyeva, Tatiana A.; Bendig, Juergen; Piletsky, Sergey A.; Ulbricht, Matthies; Schedler, Uwe

2001-02-01

Commercial polymer microfiltration membranes were surface-modified with a graft copolymer of a functional monomer and a crosslinker in the presence of a template (triazine-herbicide). As result, membranes covered with a thin layer of imprinted polymer (MIP) selective to the template were obtained. The influence of the polymerization conditions on membrane recognition properties was studied by membranes

Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

DEFF Research Database (Denmark)

Habel, Joachim Erich Otto; Hansen, Michael; Kynde, Søren

2015-01-01

In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs...... thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes.......In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs...... for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional...

An investigation on polymeric blend mixed matrix membranes of ...

African Journals Online (AJOL)

Polymeric membranes have been vastly used for gas separation purposes however they have an upper-bound trade off problem which is the reason why this research work is focusing on inorganic filler added to polymer blend membranes to enhance the selectivity and permeability of the resulted membranes. Different ...

Template Synthesis of Nanostructured Polymeric Membranes by Inkjet Printing.

Science.gov (United States)

Gao, Peng; Hunter, Aaron; Benavides, Sherwood; Summe, Mark J; Gao, Feng; Phillip, William A

2016-02-10

The fabrication of functional nanomaterials with complex structures has been serving great scientific and practical interests, but current fabrication and patterning methods are generally costly and laborious. Here, we introduce a versatile, reliable, and rapid method for fabricating nanostructured polymeric materials. The novel method is based on a combination of inkjet printing and template synthesis, and its utility and advantages in the fabrication of polymeric nanomaterials is demonstrated through three examples: the generation of polymeric nanotubes, nanowires, and thin films. Layer-by-layer-assembled nanotubes can be synthesized in a polycarbonate track-etched (PCTE) membrane by printing poly(allylamine hydrochloride) and poly(styrenesulfonate) sequentially. This sequential deposition of polyelectrolyte ink enables control over the surface charge within the nanotubes. By a simple change of the printing conditions, polymeric nanotubes or nanowires were prepared by printing poly(vinyl alcohol) in a PCTE template. In this case, the high-throughput nature of the method enables functional nanomaterials to be generated in under 3 min. Furthermore, we demonstrate that inkjet printing paired with template synthesis can be used to generate patterns comprised of chemically distinct nanomaterials. Thin polymeric films of layer-by-layer-assembled poly(allylamine hydrochloride) and poly(styrenesulfonate) are printed on a PCTE membrane. Track-etched membranes covered with the deposited thin films reject ions and can potentially be utilized as nanofiltration membranes. When the fabrication of these different classes of nanostructured materials is demonstrated, the advantages of pairing template synthesis with inkjet printing, which include fast and reliable deposition, judicious use of the deposited materials, and the ability to design chemically patterned surfaces, are highlighted.

Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via {gamma}-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Chirachanchai, S.; Kumkrong, A. [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok (Thailand); Ishida, Hatsuo [Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH (United States)

2000-03-01

Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3{alpha}, 12{alpha} -dihydroxy-5{beta}-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by {gamma}-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via γ-ray irradiation

International Nuclear Information System (INIS)

Chirachanchai, S.; Kumkrong, A.; Ishida, Hatsuo

2000-01-01

Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3α, 12α -dihydroxy-5β-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by γ-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

A balance between membrane elasticity and polymerization energy sets the shape of spherical clathrin coats

Science.gov (United States)

Saleem, Mohammed; Morlot, Sandrine; Hohendahl, Annika; Manzi, John; Lenz, Martin; Roux, Aurélien

2015-02-01

In endocytosis, scaffolding is one of the mechanisms to create membrane curvature by moulding the membrane into the spherical shape of the clathrin cage. However, the impact of membrane elastic parameters on the assembly and shape of clathrin lattices has never been experimentally evaluated. Here, we show that membrane tension opposes clathrin polymerization. We reconstitute clathrin budding in vitro with giant unilamellar vesicles (GUVs), purified adaptors and clathrin. By changing the osmotic conditions, we find that clathrin coats cause extensive budding of GUVs under low membrane tension while polymerizing into shallow pits under moderate tension. High tension fully inhibits polymerization. Theoretically, we predict the tension values for which transitions between different clathrin coat shapes occur. We measure the changes in membrane tension during clathrin polymerization, and use our theoretical framework to estimate the polymerization energy from these data. Our results show that membrane tension controls clathrin-mediated budding by varying the membrane budding energy.

Development and characterization of polymeric membranes for water desalination

International Nuclear Information System (INIS)

Bresciani, Danusa; Guimaraes, Danilo H.; Santos, Diego K.M.; Brioude, Michel M.; Jose, Nadia M.; Prado, Luis A.S.A.

2009-01-01

This work reports a development of polymeric membranes for water desalination by reverse osmosis. The polyester was synthesized by the reaction between glycerol, and dicarboxylic acids, and was coded PAF. Cellulose acetate/PAF blends containing 10% and 30% of polyester PAF blends were prepared using compression molding. The materials were characterized by DRX, DSC, TGA and SEM techniques. The results blends showed good thermal resistance and thermal events due to the individual components of the blends. The membranes exhibited a good performance in comparison to the neat cellulose acetate membrane. The addition of PAF in the polyester composition of the polymeric blends caused a significant increase of the salt retention of the studied samples. (author)

Absence of first-order unbinding transitions of fluid and polymerized membranes

Science.gov (United States)

Grotehans, Stefan; Lipowsky, Reinhard

1990-01-01

Unbinding transitions of fluid and polymerized membranes are studied by renormalization-group (RG) methods. Two different RG schemes are used and found to give rather consistent results. The fixed-point structure of both RG's exhibits a complex behavior as a function of the decay exponent tau for the fluctuation-induced interaction of the membranes. For tau greater than tau(S2) interacting membranes can undergo first-order transitions even in the strong-fluctuation regime. These estimates for tau(S2) imply, however, that both fluid and polymerized membranes unbind in a continuous way in the absence of lateral tension.

Structure and organization of nanosized-inclusion-containing bilayer membranes

Science.gov (United States)

Ren, Chun-Lai; Ma, Yu-Qiang

2009-07-01

Based on a considerable amount of experimental evidence for lateral organization of lipid membranes which share astonishingly similar features in the presence of different inclusions, we use a hybrid self-consistent field theory (SCFT)/density-functional theory (DFT) approach to deal with bilayer membranes embedded by nanosized inclusions and explain experimental findings. Here, the hydrophobic inclusions are simple models of hydrophobic drugs or other nanoparticles for biomedical applications. It is found that lipid/inclusion-rich domains are formed at moderate inclusion concentrations and disappear with the increase in the concentration of inclusions. At high inclusion content, chaining of inclusions occurs due to the effective depletion attraction between inclusions mediated by lipids. Meanwhile, the increase in the concentration of inclusions can also cause thickening of the membrane and the distribution of inclusions undergoes a layering transition from one-layer structure located in the bilayer midplane to two-layer structure arranged into the two leaflets of a bilayer. Our theoretical predictions address the complex interactions between membranes and inclusions suggesting a unifying mechanism which reflects the competition between the conformational entropy of lipids favoring the formation of lipid- and inclusion-rich domains in lipids and the steric repulsion of inclusions leading to the uniform dispersion.

Corona-induced graft polymerization for surface modification of porous polyethersulfone membranes

International Nuclear Information System (INIS)

Zhu Liping; Zhu Baoku; Xu Li; Feng Yongxiang; Liu Fu; Xu Youyi

2007-01-01

Graft polymerization of acrylic acid (AA) onto porous polyethersulfone (PES) membrane surfaces was developed using corona discharge in atmospheric ambience as an activation process followed by polymerization of AA in aqueous solution. The effects of the corona parameters and graft polymerization conditions on grafting yield (GY) of AA were investigated. The grafting of AA on the PES membranes was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy (XPS) analysis. Porosimetry measurements indicate the average pore diameters and porosities of the modified membranes decrease with the increase of the GY. The hydrophilicity and surface wetting properties of the original and modified membranes were evaluated by observing the dynamic changes of water contact angles. It is found that the grafting of AA occurs not only on the membrane surfaces, but also on the pore walls of the cells inside the membrane. The permeability experiments of protein solution reveal that the grafting of PAA endows the modified membranes with enhanced fluxes and anti-fouling properties. The optimized GY of AA is in the range of 150-200 μg/cm 2 . In addition, the tensile experiments show the corona discharge treatment with the power lower than 150 W yields little damage to the mechanical strength of the membranes

Preparation of immobilized enzyme membrane by radiation-cast-polymerization

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1989-01-01

The preparation of immobilized enzyme membranes was studied by radiation cast-polymerization at low temperatures using cellulase enzyme, hydrophilic and hydrophobic monomers. The enzyme activity of the membranes was affected by monomer concentration, membrane thickness, and hydrophilicity of monomer, in which the membranes with 100 μm thickness from high monomer concentration (80%) had high enzyme activity, which was similar to that of the membranes with 1.0 mm thickness from low monomer concentration (20%). (author)

Instrumentation for Measurement of Gas Permeability of Polymeric Membranes

Science.gov (United States)

Upchurch, Billy T.; Wood, George M.; Brown, Kenneth G.; Burns, Karen S.

1993-01-01

A mass spectrometric 'Dynamic Delta' method for the measurement of gas permeability of polymeric membranes has been developed. The method is universally applicable for measurement of the permeability of any gas through polymeric membrane materials. The usual large sample size of more than 100 square centimeters required for other methods is not necessary for this new method which requires a size less than one square centimeter. The new method should fulfill requirements and find applicability for industrial materials such as food packaging, contact lenses and other commercial materials where gas permeability or permselectivity properties are important.

Solvent sorption measurements in polymeric membranes with ATR-IR spectroscopy

NARCIS (Netherlands)

Manito Pereira, A.M.; Lopes, M.C.; Timmer, J.M.K.; Keurentjes, J.T.F.

2005-01-01

Long-term stability and performance of polymeric membranes in solvent and mixed solvent media can be reduced due to sorption and swelling of the membrane matrix. For this reason quantification of sorption and swelling is of major importance for the development of future applications of membrane

Polymeric molecular sieve membranes for gas separation

Science.gov (United States)

Dai, Sheng; Qiao, Zhenan; Chai, Songhai

2017-08-15

A porous polymer membrane useful in gas separation, the porous polymer membrane comprising a polymeric structure having crosslinked aromatic groups and a hierarchical porosity in which micropores having a pore size less than 2 nm are present at least in an outer layer of the porous polymer membrane, and macropores having a pore size of over 50 nm are present at least in an inner layer of the porous polymer membrane. Also described are methods for producing the porous polymer membrane in which a non-porous polymer membrane containing aromatic rings is subjected to a Friedel-Crafts crosslinking reaction in which a crosslinking molecule crosslinks the aromatic rings in the presence of a Friedel-Crafts catalyst and organic solvent under sufficiently elevated temperature, as well as methods for using the porous polymer membranes for gas or liquid separation, filtration, or purification.

Surface modification of polypropylene membrane by polyethylene glycol graft polymerization

Energy Technology Data Exchange (ETDEWEB)

Abednejad, Atiye Sadat, E-mail: atiyeabednejad@gmail.com [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Amoabediny, Ghasem [Department of Life Science Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of); Research Center for New Technologies in Life Science Engineering, University of Tehran, P.O. Box 63894-14179, Tehran (Iran, Islamic Republic of); Ghaee, Azadeh [Department of Biomedical Engineering, Faculty of New Sciences and Technologies, University of Tehran, P.O. Box 14395-1561, Tehran (Iran, Islamic Republic of)

2014-09-01

Polypropylene hollow fiber microporous membranes have been used in a wide range of applications, including blood oxygenator. The hydrophobic feature of the polypropylene surface causes membrane fouling. To minimize fouling, a modification consisting of three steps: surface activation in H{sub 2} and O{sub 2} plasma, membrane immersion in polyethylene glycol (PEG) and plasma graft polymerization was performed. The membranes were characterized by contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), tensile test, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Oxygen transfer of modified membranes was also tested. The stability of grafted PEG was measured in water and in phosphate buffer saline (PBS) at 37 °C. Blood compatibility of modified surfaces was evaluated by the platelet adhesion method. Water contact angel reduction from 110° to 72° demonstrates the enhanced hydrophilicity, and XPS results verify the presence of oxygenated functional groups due to the peak existence in 286 eV as a result of PEG grafting. The results clearly indicate that plasma graft-polymerization of PEG is an effective way for antifouling improvement of polypropylene membranes. Also, the results show that oxygen transfer changes in PEG grafted membranes are not significant. - Highlights: • H{sub 2} and O{sub 2} plasma graft polymerization of PEG on polypropylene membrane was carried out. • Changes in surface properties were investigated by FTIR, XPS, SEM, and AFM. • Surface wettability enhanced as a result of poly ethylene glycol grafting. • PEG grafting degree increase causes reduction of fouling and adhesion.

Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

Science.gov (United States)

Habel, Joachim; Hansen, Michael; Kynde, Søren; Larsen, Nanna; Midtgaard, Søren Roi; Jensen, Grethe Vestergaard; Bomholt, Julie; Ogbonna, Anayo; Almdal, Kristoffer; Schulz, Alexander; Hélix-Nielsen, Claus

2015-01-01

In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes. PMID:26264033

Advanced Polymeric and Organic–Inorganic Membranes for Pressure-Driven Processes

KAUST Repository

Le, Ngoc Lieu; Phuoc, Duong; Nunes, Suzana Pereira

2017-01-01

The state-of-the-art of membranes for reverse osmosis, nanofiltration, and gas separation is shortly reviewed, taking in account the most representative examples currently in application. Emphasis is also done on recent developments of advanced polymeric and organic–inorganic materials for pressure-driven processes. Many of the more recent membranes are not only polymeric but also contain an inorganic phase. Tailoring innovative materials with organic and inorganic phases coexisting in a nanoscale with multifunctionalization is an appealing approach to control at the same time diffusivity and gas solubility. Other advanced materials that are now being considered for membrane development are organic or organic–inorganic self-assemblies, metal-organic frameworks, and different forms of carbon fillers.

Advanced Polymeric and Organic–Inorganic Membranes for Pressure-Driven Processes

KAUST Repository

Le, Ngoc Lieu

2017-02-13

The state-of-the-art of membranes for reverse osmosis, nanofiltration, and gas separation is shortly reviewed, taking in account the most representative examples currently in application. Emphasis is also done on recent developments of advanced polymeric and organic–inorganic materials for pressure-driven processes. Many of the more recent membranes are not only polymeric but also contain an inorganic phase. Tailoring innovative materials with organic and inorganic phases coexisting in a nanoscale with multifunctionalization is an appealing approach to control at the same time diffusivity and gas solubility. Other advanced materials that are now being considered for membrane development are organic or organic–inorganic self-assemblies, metal-organic frameworks, and different forms of carbon fillers.

Permeation of supercritical carbon dioxide through polymeric hollow fiber membranes

NARCIS (Netherlands)

Patil, V.E.; Broeke, van den L.J.P.; Vercauteren, F.F.; Keurentjes, J.T.F.

2006-01-01

Permeation of carbon dioxide was measured for two types of composite polymeric hollow fiber membranes for feed pressures up to 18 MPa at a temp. of 313 K. support membrane. The membranes consist of a polyamide copolymer (IPC) layer or a poly(vinyl alc.) (PVA) layer on top of a polyethersulfone

Functionalization of nanochannels by radio-induced grafting polymerization on PET track-etched membranes

International Nuclear Information System (INIS)

Soto Espinoza, S.L.; Arbeitman, C.R.; Clochard, M.C.; Grasselli, M.

2014-01-01

The application of swift-heavy ion bombardment to polymers is a well-established technique to manufacture micro- and nanopores onto polymeric films to obtain porous membranes. A few years ago, it was realized that, during ion bombardment, the high energy deposition along the ion path through the polymer reached cylindrical damage regions corresponding to the core trace and the penumbra. After the etching procedure, there are still enough active sites left in the penumbra that can be used to initiate a polymerization process selectively inside the membrane pores. In this study, we report the grafting polymerization of glycidyl methacrylate onto etched PET foils to obtain functionalized nanochannels. Grafted polymers were labeled with a fluorescent tag and analyzed by different fluorescence techniques such as direct fluorescence, fluorescence microscopy and confocal microscopy. These techniques allowed identifying and quantifying the grafted regions on the polymeric foils. - Highlights: • Irradiated PET foils with swift-heavy ions were etched and grafted in a step-by-step process. • Grafting polymerization was performed on the remaining active sites after etching. • Track-etched PET membranes were fluorescently labeled by chemical functionalization. • Functionalized track-etched PET membranes were analyzed by fluorescence and confocal microscopy

Versatile and Rapid Postfunctionalization from Cyclodextrin Modified Host Polymeric Membrane Substrate.

Science.gov (United States)

Deng, Jie; Liu, Xinyue; Zhang, Shuqing; Cheng, Chong; Nie, Chuanxiong; Zhao, Changsheng

2015-09-08

Surface modification has long been of great interest to impart desired functionalities to the bioimplants. However, due to the limitations of recent technologies in surface modification, it is highly desirable to explore novel protocols, which can advantageously and efficiently endow the inert material surfaces with versatile biofunctionalities. Herein, to achieve versatile and rapid postfunctionalization of polymeric membrane, we demonstrate a new strategy for the fabrication of β-cyclodextrin (β-CD) modified host membrane substrate that can recognize a series of well-designed guest macromolecules. The surface assembly procedure was driven by the host-guest interaction between adamantane (Ad) and β-CD. β-CD immobilized host membrane was fabricated via two steps: (1) epoxy groups enriched poly(ether sulfone) (PES) membrane was first prepared via in situ cross-linking polymerization and subsequently phase separation; (2) mono-6-deoxy-6-ethylenediamine-β-CD (EDA-β-CD) was then anchored onto the surface of the epoxy functionalized PES membrane to obtain PES-CD. Subsequently, three types of Ad-terminated polymers, including Ad-poly(styrenesulfonate-co-sodium acrylate) (Ad-PSA), Ad-methoxypoly(ethylene glycol) (Ad-PEG), and Ad-poly(methyl chloride-quaternized 2-(dimethylamino)ethyl methacrylate (Ad-PMT), were separately assembled onto the β-CD immobilized surfaces to endow the membranes with anticoagulant, antifouling, and antibacterial capability, respectively. Activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT) measurements were carried out to explore the anticoagulant activity. The antifouling capability was evaluated via protein adsorption and platelet adhesion measurements. Moreover, Staphyllococcous aureus (S. aureus) was selected as model bacteria to evaluate the antibacterial ability of the functionalized membranes. The results indicated that well-regulated blood compatibility, antifouling capability, and

Preparation of membranes using solvent-less vapor deposition followed by in-situ polymerization

Science.gov (United States)

O'Brien, Kevin C [San Ramon, CA; Letts, Stephan A [San Ramon, CA; Spadaccini, Christopher M [Oakland, CA; Morse, Jeffrey C [Pleasant Hill, CA; Buckley, Steven R [Modesto, CA; Fischer, Larry E [Los Gatos, CA; Wilson, Keith B [San Ramon, CA

2010-07-13

A system of fabricating a composite membrane from a membrane substrate using solvent-less vapor deposition followed by in-situ polymerization. A first monomer and a second monomer are directed into a mixing chamber in a deposition chamber. The first monomer and the second monomer are mixed in the mixing chamber providing a mixed first monomer and second monomer. The mixed first monomer and second monomer are solvent-less vapor deposited onto the membrane substrate in the deposition chamber. The membrane substrate and the mixed first monomer and second monomer are heated to produce in-situ polymerization and provide the composite membrane.

Porous polymeric membranes with thermal and solvent resistance

KAUST Repository

Pulido, Bruno; Waldron, Christopher; Zolotukhin, M.G.; Nunes, Suzana Pereira

2017-01-01

Polymeric membranes are highly advantageous over their ceramic counterparts in terms of the simplicity of the manufacturing process, cost and scalability. Their main disadvantages are low stability at temperatures above 200 °C, and in organic

Effect of amine structure on CO2 capture by polymeric membranes.

Science.gov (United States)

Taniguchi, Ikuo; Kinugasa, Kae; Toyoda, Mariko; Minezaki, Koki

2017-01-01

Poly(amidoamine)s (PAMAMs) incorporated into a cross-linked poly(ethylene glycol) exhibited excellent CO 2 separation properties over H 2 . However, the CO 2 permeability should be increased for practical applications. Monoethanolamine (MEA) used as a CO 2 determining agent in the current CO 2 capture technology at demonstration scale was readily immobilized in poly(vinyl alcohol) (PVA) matrix by solvent casting of aqueous mixture of PVA and the amine. The resulting polymeric membranes can be self-standing with the thickness above 3 μm and the amine fraction less than 80 wt%. The gas permeation properties were examined at 40 °C and under 80% relative humidity. The CO 2 separation performance increased with increase of the amine content in the polymeric membranes. When the amine fraction was 80 wt%, the CO 2 permeability coefficient of MEA containing membrane was 604 barrer with CO 2 selectivity of 58.5 over H 2 , which was much higher than the PAMAM membrane (83.7 barrer and 51.8, respectively) under the same operation conditions. On the other hand, ethylamine (EA) was also incorporated into PVA matrix to form a thin membrane. However, the resulting polymeric membranes exhibited slight CO 2 -selective gas permeation properties. The hydroxyl group of MEA was crucial for high CO 2 separation performance.

Grafting of molecularly imprinted polymer to porous polyethylene filtration membranes by plasma polymerization.

Science.gov (United States)

Cowieson, D; Piletska, E; Moczko, E; Piletsky, S

2013-08-01

An application of plasma-induced grafting of polyethylene membranes with a thin layer of molecularly imprinted polymer (MIP) was presented. High-density polyethylene (HDPE) membranes, "Vyon," were used as a substrate for plasma grafting modification. The herbicide atrazine, one of the most popular targets of the molecular imprinting, was chosen as a template. The parameters of the plasma treatment were optimized in order to achieve a good balance between polymerization and ablation processes. Modified HDPE membranes were characterized, and the presence of the grafted polymeric layer was confirmed based on the observed weight gain, pore size measurements, and infrared spectrometry. Since there was no significant change in the porosity of the modified membranes, it was assumed that only a thin layer of the polymer was introduced on the surface. The experiments on the re-binding of the template atrazine to the membranes modified with MIP and blank polymers were performed. HDPE membranes which were grafted with polymer using continuous plasma polymerization demonstrated the best result which was expressed in an imprinted factor equal to 3, suggesting that molecular imprinting was successfully achieved.

Hyper-cross-linked, hybrid membranes via interfacial polymerization

NARCIS (Netherlands)

Raaijmakers, Michiel

2015-01-01

Hyper-cross-linked, hybrid membranes consist of covalent networks of alternating organic and inorganic, or biological groups. This thesis reports on the preparation of such hybrid networks via interfacial polymerization. The structure-property relationships of the hybrid networks depend strongly on

Spin Label Studies of the Hemoglobin-Membrane Interaction During Sickle Hemoglobin Polymerization

International Nuclear Information System (INIS)

Falcon Dieguez, Jose E.; Rodi, Pablo; Lores Guevara, Manuel A.; Gennaro, Ana Maria

2009-12-01

An enhanced hemoglobin-membrane association has been previously documented in Sickle Cell Anemia. However, it is not known how this interaction is modified during the hemoglobin S polymerization process. In this work, we use a model of reconstituted erythrocytes from ghost membranes whose cytoskeleton proteins had been previously labeled with the 4-maleimido Tempo spin label, and that were subsequently resealed with hemoglobin S or A solutions. Using EPR spectroscopy, we studied the time dependence of the spectral W/S parameter, indicative of the conformational state of cytoskeleton proteins (mainly spectrin) under spontaneous deoxygenation, with the aim of detecting the eventual effects due to hemoglobin S polymerization. The differences observed in the temporal behaviour of W/S in erythrocytes reconstituted with both hemoglobins were considered as experimental evidence of an increment in hemoglobin S-membrane interaction, as a result of the polymerization process of hemoglobin S under spontaneous deoxygenation. (author)

Water vapor and Gas Transport through Polymeric Membranes

NARCIS (Netherlands)

Metz, S.J.

2003-01-01

Water vapor transport through polymeric materials plays an important role in a large number of applications such as: food packaging, breathable clothing, roofing membranes, diapers, and the removal of water vapor from gas streams (e.g. dehydration of natural gas or the drying of compressed air).

Surface patterning of polymeric separation membranes and its influence on the filtration performance

Science.gov (United States)

Maruf, Sajjad

Polymeric membrane based separation technologies are crucial for addressing the global issues such as water purification. However, continuous operations of these processes are often hindered by fouling which increases mass transport resistance of the membrane to permeation and thus the energy cost, and eventually replacement of the membrane in the system. In comparison to other anti-fouling strategies, the use of controlled surface topography to mitigate fouling has not been realized mainly due to the lack of methods to create targeted topography on the porous membrane surface. This thesis aims to develop a new methodology to create surface-patterned polymeric separation membrane to improve their anti-fouling characteristics during filtration. First, successful fabrication of sub-micron surface patterns directly on a commercial ultrafiltration (UF) membrane surface using nanoimprint lithographic (NIL) technique was demonstrated. Comprehensive filtration studies revealed that the presence of these sub-micron surface patterns mitigates not only the onset of colloidal particle deposition, but also lowers the rate of growth of cake layer after initial deposition, in comparison with un-patterned membranes. The anti-fouling effects were also observed for model protein solutions. Staged filtration experiments, with backwash cleaning, revealed that the permeate flux of the patterned membrane after protein fouling was considerably higher than that of the pristine or un-patterned membrane. In addition to the surface-patterning of UF membranes, successful fabrication of a surface-patterned thin film composite (TFC) membrane was shown for the first time. A two-step fabrication process was carried out by (1) nanoimprinting a polyethersulfone (PES) support using NIL, and (2) forming a thin dense film atop the PES support via interfacial polymerization (IP). Fouling experiments suggest that the surface patterns alter the hydrodynamics at the membrane-feed interface, which is

Field testing of polymeric mesh and ash-based ceramic membranes ...

African Journals Online (AJOL)

This paper presents the initial findings of field testing of 2 low-cost membrane filters, viz. 30 ìm polymeric mesh and 2–6 ìm macroporous waste-ash based ceramic filter, in a submerged membrane bioreactor (MBR) employing batch anoxic and aerobic conditions. The influent was raw wastewater from a residential complex ...

Development of polymeric palladium-nanoparticle membrane-installed microflow devices and their application in hydrodehalogenation.

Science.gov (United States)

Yamada, Yoichi M A; Watanabe, Toshihiro; Ohno, Aya; Uozumi, Yasuhiro

2012-02-13

We have developed a variety of polymeric palladium-nanoparticle membrane-installed microflow devices. Three types of polymers were convoluted with palladium salts under laminar flow conditions in a microflow reactor to form polymeric palladium membranes at the laminar flow interface. These membranes were reduced with aqueous sodium formate or heat to create microflow devices that contain polymeric palladium-nanoparticle membranes. These microflow devices achieved instantaneous hydrodehalogenation of aryl chlorides, bromides, iodides, and triflates by 10-1000 ppm within a residence time of 2-8 s at 50-90 °C by using safe, nonexplosive, aqueous sodium formate to quantitatively afford the corresponding hydrodehalogenated products. Polychlorinated biphenyl (10-1000 ppm) and polybrominated biphenyl (1000 ppm) were completely decomposed under similar conditions, yielding biphenyl as a fungicidal compound. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterizing free volumes and layer structures in polymeric membranes using slow positron annihilation spectroscopy

International Nuclear Information System (INIS)

Jean, Y C; Chen Hongmin; Awad, Somia; Zhang Sui; Chen Hangzheng; Lau, Cher Hon; Wang Huan; Li Fuyun; Chung, Tai-Shung; Lee, L James; Huang, James

2011-01-01

Positron annihilation spectroscopy coupled with a newly built slow positron beam at National University of Singapore has been used to study the free volume, pore, and depth profile (0 - 10 μm) in cellulose acetate polymeric membrane at the bottom and top sides of membranes for ionic separation in water purification applications. The S and R parameters from Doppler broadening energy of annihilation radiation representing free volumes (0.1-1 nm size) and pores (>1 nm-μm) as a function of depth have been analyzed into multilayers, i.e. skin dense, transition, and porous layers, respectively. The top side of membrane has large free volumes and pores and the bottom side has a skin dense layer, which plays a key role in membrane performance. Positron annihilation lifetime results provide additional information about free-volume size and distribution at the atomic and molecular scale in polymeric membrane systems. Doppler broadening energy and lifetime spectroscopies coupled with a variable mono-energy slow positron beam are sensitive and novel techniques for characterization of polymeric membrane in separation applications.

Polymer Inclusion Membranes with Strip Dispersion

Directory of Open Access Journals (Sweden)

Yueh-Hsien Li

2017-06-01

Full Text Available The present work investigated the permeation of indium ions through a polymer inclusion membrane (PIM, prepared with cellulose triacetate (CTA as the base polymer, tris(2-butoxyethyl phosphate (TBEP as the plasticizer and di-(2-ethylhexylphosphoric acid (D2EHPA as the extractant. With 5 M HCl aqueous solution as the strip solution, we observed an initial indium permeability of 2.4 × 10−4 m/min. However, the permeability decreases with time, dropping to about 3.4 × 10−5 m/min after 200 min of operation. Evidence was obtained showing that hydrolysis of CTA occurred, causing a dramatic decrease in the feed pH (protons transported from strip to feed solutions and a loss of extractant and plasticizer from the membrane, and then leading to the loss of indium permeability. To alleviate the problem of hydrolysis, we proposed an operation scheme called polymer inclusion membranes with strip dispersion: dispersing the strip solution in extractant-containing oil and then bringing the dispersion to contact with the polymer membrane. Since the strong acid was dispersed in oil, the membrane did not directly contact the strong acid at all times, and membrane hydrolysis was thus alleviated and the loss of indium permeability was effectively prevented. With the proposed scheme, a stable indium permeability of 2.5 × 10−4 m/min was obtained during the whole time period of the permeation experiment.

Erythrocyte membrane modified janus polymeric motors for thrombus therapy

NARCIS (Netherlands)

Shao, Jingxin; Abdelghani, Mona; Shen, Guizhi; Cao, Shoupeng; Williams, David S.; van Hest, Jan C.M.

2018-01-01

We report the construction of erythrocyte membrane-cloaked Janus polymeric motors (EM-JPMs) which are propelled by near-infrared (NIR) laser irradiation and are successfully applied in thrombus ablation. Chitosan (a natural polysaccharide with positive charge, CHI) and heparin (glycosaminoglycan

Feedback Interactions of Polymerized Actin with the Cell Membrane: Waves, Pulses, and Oscillations

Science.gov (United States)

Carlsson, Anders

Polymerized filaments of the protein actin have crucial functions in cell migration, and in bending the cell membrane to drive endocytosis or the formation of protrusions. The nucleation and polymerization of actin filaments are controlled by upstream agents in the cell membrane, including nucleation-promoting factors (NPFs) that activate the Arp2/3 complex to form new branches on pre-existing filaments. But polymerized actin (F-actin) also feeds back on the assembly of NPFs. We explore the effects of the resulting feedback loop of F-actin and NPFs on two phenomena: actin pulses that drive endocytosis in yeast, and actin waves traveling along the membrane of several cell types. In our model of endocytosis in yeast, the actin network is grown explicitly in three dimensions, exerts a negative feedback interaction on localized patch of NPFs in the membrane, and bends the membrane by exerting a distribution of forces. This model explains observed actin and NPF pulse dynamics, and the effects of several interventions including i) NPF mutations, ii) inhibition of actin polymerization, and iii) deletion of a protein that allows F-actin to bend the cell membrane. The model predicts that mutation of the active region of an NPF will enhance the accumulation of that NPF, and we confirm this prediction by quantitative fluorescence microscopy. For actin waves, we treat a similar model, with NPFs distributed over a larger region of the cell membrane. This model naturally generates actin waves, and predicts a transition from wave behavior to spatially localized oscillations when NPFs are confined to a small region. We also predict a transition from waves to static polarization as the negative-feedback coupling between F-actin and the NPFs is reduced. Supported by NIGMS Grant R01 GM107667.

A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

Directory of Open Access Journals (Sweden)

Elbadawy A. Kamoun

2017-05-01

Full Text Available This review presents the past and current efforts with a brief description on the featured properties of hydrogel membranes fabricated from biopolymers and synthetic ones for wound dressing applications. Many endeavors have been exerted during past ten years for developing new artificial polymeric membranes, which fulfill the demanded conditions for the treatment of skin wounds. This review mainly focuses on representing specifications of ideal polymeric wound dressing membranes, such as crosslinked hydrogels compatible with wound dressing purposes. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite or hybrid hydrogel membranes to achieve the typical wound dressing requirements.

Antifouling coatings via plasma polymerization and atom transfer radical polymerization on thin film composite membranes for reverse osmosis

Science.gov (United States)

Hirsch, Ulrike; Ruehl, Marco; Teuscher, Nico; Heilmann, Andreas

2018-04-01

A major drawback to otherwise highly efficient membrane-based desalination techniques like reverse osmosis (RO) is the susceptibility of the membranes to biofouling. In this work, a combination of plasma activation, plasma bromination and surface-initiated atom transfer radical polymerization (si-ATRP) of hydrophilic and zwitterionic monomers, namely hydroxyethyl methacrylate (HEMA), 2-methacryloyloxyethyl phosphorylcholine (MPC) and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), was applied to generate non-specific, anti-adhesive coatings on thin film composite (TFC) membranes. The antifouling effect of the coatings was shown by short-time batch as well as long-time steady state cultivation experiments with the microorganism Pseudomonas fluorescens. It could be shown that plasma functionalization and polymerization is possible on delicate thin film composite membranes without restricting their filtration performance. All modified membranes showed an increased resistance towards the adhesion of Pseudomonas fluorescens. On average, the biofilm coverage was reduced by 51.4-12.6% (for HEMA, SBMA, and MPC), the highest reduction was monitored for MPC with a biofilm reduction by 85.4%. The hydrophilic coatings applied did not only suppress the adhesion of Pseudomonas fluorescens, but also significantly increase the permeate flux of the membranes relative to uncoated membranes. The stability of the coatings was however not ideal and will have to be improved for future commercial use.

Amine Enrichment of Thin-Film Composite Membranes via Low Pressure Plasma Polymerization for Antimicrobial Adhesion.

Science.gov (United States)

Reis, Rackel; Dumée, Ludovic F; He, Li; She, Fenghua; Orbell, John D; Winther-Jensen, Bjorn; Duke, Mikel C

2015-07-15

Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.

Surface functionalization of a polymeric lipid bilayer for coupling a model biological membrane with molecules, cells, and microstructures.

Science.gov (United States)

Morigaki, Kenichi; Mizutani, Kazuyuki; Saito, Makoto; Okazaki, Takashi; Nakajima, Yoshihiro; Tatsu, Yoshiro; Imaishi, Hiromasa

2013-02-26

We describe a stable and functional model biological membrane based on a polymerized lipid bilayer with a chemically modified surface. A polymerized lipid bilayer was formed from a mixture of two diacetylene-containing phospholipids, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DiynePC) and 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphoethanolamine (DiynePE). DiynePC formed a stable bilayer structure, whereas the ethanolamine headgroup of DiynePE enabled functional molecules to be grafted onto the membrane surface. Copolymerization of DiynePC and DiynePE resulted in a robust bilayer. Functionalization of the polymeric bilayer provided a route to a robust and biomimetic surface that can be linked with biomolecules, cells, and three-dimensional (3D) microstructures. Biotin and peptides were grafted onto the polymeric bilayer for attaching streptavidin and cultured mammalian cells by molecular recognition, respectively. Nonspecific adsorption of proteins and cells on polymeric bilayers was minimum. DiynePE was also used to attach a microstructure made of an elastomer (polydimethylsiloxan: PDMS) onto the membrane, forming a confined aqueous solution between the two surfaces. The microcompartment enabled us to assay the activity of a membrane-bound enzyme (cyochrome P450). Natural (fluid) lipid bilayers were incorporated together with membrane-bound proteins by lithographically polymerizing DiynePC/DiynePE bilayers. The hybrid membrane of functionalized polymeric bilayers and fluid bilayers offers a novel platform for a wide range of biomedical applications including biosensor, bioassay, cell culture, and cell-based assay.

Analysis of ultrasonic techniques for the characterization of microfiltration polymeric membranes

International Nuclear Information System (INIS)

Lucas, Carla S.; Baroni, Douglas B.; Costa, Antonio M.L.M.; Bittencourt, Marcelo S.Q.

2009-01-01

The use of polymeric membranes is extremely important in several industries such as nuclear, biotechnology, chemical and pharmaceutical. In the nuclear area, for instance, systems based on membrane separation technologies are currently being used in the treatment of radioactive liquid effluent, and new technologies using membranes are being developed at a great rate. The knowledge of the physical characteristics of these membranes, such as, pore size and the pore size distribution, is very important to the membranes separation processes. Only after these characteristics are known is it possible to determine the type and to choose a particular membrane for a specific application. In this work, two ultrasonic non destructive techniques were used to determine the porosity of membranes: pulse echo and transmission. A 25 MHz immersion transducer was used. Ultrasonic signals were acquired, for both techniques, after the ultrasonic waves passed through a microfiltration polymeric membrane of pore size of 0.45 μm and thickness of 180 μm. After the emitted ultrasonic signal crossed the membrane, the received signal brought several information on the influence of the membrane porosity in the standard signal of the ultrasonic wave. The ultrasonic signals were acquired in the time domain and changed to the frequency domain by application of the Fourier Fast Transform (FFT), thus generating the material frequency spectrum. For the pulse echo technique, the ultrasonic spectrum frequency changed after the ultrasonic wave crossed the membrane. With the transmission technique there was only a displacement of the ultrasonic signal at the time domain. (author)

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.

2018-05-18

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane is prepared by interfacial polymerization on a cellulose support. The cellulose support is prepared by nonsolvent‐induced phase separation from a dope solution containing an ionic liquid as an environmentally friendly solvent (negligible vapor pressure). The polyester film is formed via the interfacial reaction between quercetin, a plant‐derived polyphenol, and terephthaloyl chloride. Alpha‐pinene is used as a green alternative solvent to dissolve terephthaloyl chloride (TPC) while quercetin is dissolved in a 0.2 m NaOH solution. The interfacial polymerization reaction is successfully confirmed by Fourier transform infrared and X‐ray photoelectron spectroscopy while scanning electron and atomic force microscopy are used to characterize the membrane structure. The composite membrane shows an outstanding performance with a molecular weight cut‐off around 330 Da combined with a dimethylformamide (DMF) permeance up to 2.8 L m−2 bar−1 h−1. The membrane is stable in strong aprotic solvents such as DMF offering potential application in the pharmaceutical and petrochemical industries.

Preparation of Zeolitic Imidazolate Framework-8 (ZIF-8) Membrane on Porous Polymeric Support via Contra-Diffusion Method

KAUST Repository

Tan, Xiaoyu

2016-01-01

way to
fabricate defect-free and thin ZIF-8 membranes on porous polymeric supports showing high selectivity and high gas permeance. The ZIF-8 layers were produced via a contra-diffusion method. Several polymeric membranes were employed as support

Complexation-Induced Phase Separation: Preparation of Metal-Rich Polymeric Membranes

KAUST Repository

Villalobos, Luis Francisco

2017-01-01

The majority of state-of-the-art polymeric membranes for industrial or medical applications are fabricated by phase inversion. Complexation induced phase separation (CIPS)—a surprising variation of this well-known process—allows direct fabrication

Fabrication of high-capacity polyelectrolyte brush-grafted porous AAO-silica composite membrane via RAFT polymerization.

Science.gov (United States)

Song, Cunfeng; Wang, Meijie; Liu, Xin; Wang, He; Chen, Xiaoling; Dai, Lizong

2017-09-01

Surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization has been utilized to fabricate high-capacity strong anion-exchange (AEX) membrane for the separation of protein. By means of RAFT polymerization, quaternized poly(3-(methacrylamidomethyl)-pyridine) brushes formed 3-dimensional nanolayers on the surface of porous anodic aluminum oxide (AAO)-silica composite membrane. The surface properties of the membranes were analyzed by SEM, water contact angle, ATR-FTIR, XPS and TGA. To investigate the adsorption performance, the new AEX membranes were applied to recover a model protein, ovalbumin (OVA). High adsorption capacities of 95.8mg/g membranes (static) and 65.3mg/g membranes (dynamic) were obtained at ambient temperature. In the further studies, up to 90% of the adsorbed OVA was efficiently eluted by using phosphate buffer-1M NaCl as elution medium. The successful separation of OVA with high purity from a mixture protein solution was also achieved by using the AEX membranes. The present study demonstrated that under mild reaction condition, RAFT polymerization can be used to fabricate ion-exchange membrane which has many remarkable features, such as high capacity and selectivity, easy elution and so on. Copyright © 2017. Published by Elsevier B.V.

Efficiency of Polymeric Membrane Graphene Oxide-TiO2 for Removal of Azo Dye

Directory of Open Access Journals (Sweden)

Elahe Dadvar

2017-01-01

Full Text Available Achieving the desired standard of drinking water quality has been one of the concerns across water treatment plants in the developing countries. Processes such as grid chamber, coagulation, sedimentation, clarification, filtration, and disinfection are typically used in water purification plants. Among these methods, unit filtration which employs polymers is one of the new technologies. There have been many studies about the use of semiconductive TiO2 with graphene oxide (GO on the base of different polymeric membranes for the removal of azo dyes, especially methylene blue (MB. Polymeric GO-TiO2 membranes have high photocatalytic, antifouling property and permeate the flux removal of organic pollutants. The aim of this study was to investigate the characteristics of different polymeric membranes such as anionic perfluorinated polymer (Nafion, cellulose acetate, polycarbonate (PC, polysulfone fluoride (PSF, and polyvinylidene fluoride (PVDF. The result of this study showed that the GO-TiO2 membrane can be used in the field of water treatment and will be used for the removal of polycyclic aromatic hydrocarbons (PAHs from wastewater.

Influence of Solutocapillary Convection on Macrovoid Defect Formation in Polymeric Membranes

Science.gov (United States)

Greenberg, Alan R.; Krantz, William B.; Todd, Paul

2003-01-01

The focus of this research project involved the dry-cast process for polymeric membrane formation, whereby evaporation of solvent from an initially homogeneous polymer/solvent/ nonsolvent solution results in phase separation and the formation of polymer-rich and polymer-lean phases. Under certain conditions the polymer-lean phase gives rise to very large and usually undesirable, tear-drop-shaped pores (size approx. 10 - 50 microns) termed macrovoids (MVs). Although in many cases the presence of MV pores has deleterious effects on membrane performance, there are a number of innovative applications where the presence of such pores is highly desirable. Although researchers have proposed a variety of mechanisms for MV formation over the past three decades, two main hypotheses are currently favored: one asserts that MV growth can be attributed solely to diffusion (the diffusive growth hypothesis), whereas the other states that solutocapillary convection (the SC hypothesis) at the MV interface contributes to growth. The overall goal of this research was to obtain a more comprehensive understanding of the fundamental mechanism of MV growth. This research incorporates a coupled modeling and experimental approach to test a solutocapillary convection hypothesis for the growth of macrovoid pores in polymeric membranes. Specifically, we utilized a modification of the first principles model developed by two of the PIs (ARG and WBK) for dry-cast CA membranes. For the experimental component, two separate and mutually complementary approaches were used to study MV growth. In the first, membranes cast in a zero-g environment aboard the NASA KC-135 aircraft were compared with those cast on the ground to assess the effect of the buoyancy force on membrane morphology and MV size and shape. In the second approach, videomicroscopy flow visualization (VMFV) was utilized to observe MV formation and growth in real time and to assess the effect of surface tension on the MV growth dynamics

Extraction or adsorption? Voltammetric assessment of protamine transfer at ionophore-based polymeric membranes.

Science.gov (United States)

Garada, Mohammed B; Kabagambe, Benjamin; Amemiya, Shigeru

2015-01-01

Cation-exchange extraction of polypeptide protamine from water into an ionophore-based polymeric membrane has been hypothesized as the origin of a potentiometric sensor response to this important heparin antidote. Here, we apply ion-transfer voltammetry not only to confirm protamine extraction into ionophore-doped polymeric membranes but also to reveal protamine adsorption at the membrane/water interface. Protamine adsorption is thermodynamically more favorable than protamine extraction as shown by cyclic voltammetry at plasticized poly(vinyl chloride) membranes containing dinonylnaphthalenesulfonate as a protamine-selective ionophore. Reversible adsorption of protamine at low concentrations down to 0.038 μg/mL is demonstrated by stripping voltammetry. Adsorptive preconcentration of protamine at the membrane/water interface is quantitatively modeled by using the Frumkin adsorption isotherm. We apply this model to ensure that stripping voltammograms are based on desorption of all protamine molecules that are transferred across the interface during a preconcentration step. In comparison to adsorption, voltammetric extraction of protamine requires ∼0.2 V more negative potentials, where a potentiometric super-Nernstian response to protamine is also observed. This agreement confirms that the potentiometric protamine response is based on protamine extraction. The voltammetrically reversible protamine extraction results in an apparently irreversible potentiometric response to protamine because back-extraction of protamine from the membrane extremely slows down at the mixed potential based on cation-exchange extraction of protamine. Significantly, this study demonstrates the advantages of ion-transfer voltammetry over potentiometry to quantitatively and mechanistically assess protamine transfer at ionophore-based polymeric membranes as foundation for reversible, selective, and sensitive detection of protamine.

Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

Science.gov (United States)

Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

2012-01-01

Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

Tuning biomimetic membrane barrier properties by hydrocarbon, cholesterol and polymeric additives

DEFF Research Database (Denmark)

Palanco, Marta Espina; Skovgaard, Nils; Hansen, Jesper Søndergaard

2017-01-01

The barrier properties of cellular membranes are increasingly attracting attention as a source of inspiration for designing biomimetic membranes. The broad range of potential technological applications makes the use of lipid and lately also polymeric materials a popular choice for constructing...... biomimetic membranes, where the barrier properties can be controlled by the composition of the membrane constituent elements. Here we investigate the membrane properties reported by the light-induced proton pumping activity of bacteriorhodopsin (bR) reconstituted in three vesicle systems of different...... membrane composition. Specifically we quantify how the resulting proton influx and efflux rates are influenced by the membrane composition using a variety of membrane modulators. We demonstrate that by adding hydrocarbons to vesicles with reconstituted bR formed from asolectin lipids the resulting...

Surface modification of nanoporous alumina membranes by plasma polymerization

Energy Technology Data Exchange (ETDEWEB)

Losic, Dusan; Cole, Martin A; Dollmann, Bjoern; Vasilev, Krasimir; Griesser, Hans J [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)], E-mail: dusan.losic@unisa.edu.au

2008-06-18

The deposition of plasma polymer coatings onto porous alumina (PA) membranes was investigated with the aim of adjusting the surface chemistry and the pore size of the membranes. PA membranes from commercial sources with a range of pore diameters (20, 100 and 200 nm) were used and modified by plasma polymerization using n-heptylamine (HA) monomer, which resulted in a chemically reactive polymer surface with amino groups. Heptylamine plasma polymer (HAPP) layers with a thickness less than the pore diameter do not span the pores but reduce their diameter. Accordingly, by adjusting the deposition time and thus the thickness of the plasma polymer coating, it is feasible to produce any desired pore diameter. The structural and chemical properties of modified membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray electron spectroscopy (XPS). The resultant PA membranes with specific surface chemistry and controlled pore size are applicable for molecular separation, cell culture, bioreactors, biosensing, drug delivery, and engineering complex composite membranes.

Surface modification of nanoporous alumina membranes by plasma polymerization

International Nuclear Information System (INIS)

Losic, Dusan; Cole, Martin A; Dollmann, Bjoern; Vasilev, Krasimir; Griesser, Hans J

2008-01-01

The deposition of plasma polymer coatings onto porous alumina (PA) membranes was investigated with the aim of adjusting the surface chemistry and the pore size of the membranes. PA membranes from commercial sources with a range of pore diameters (20, 100 and 200 nm) were used and modified by plasma polymerization using n-heptylamine (HA) monomer, which resulted in a chemically reactive polymer surface with amino groups. Heptylamine plasma polymer (HAPP) layers with a thickness less than the pore diameter do not span the pores but reduce their diameter. Accordingly, by adjusting the deposition time and thus the thickness of the plasma polymer coating, it is feasible to produce any desired pore diameter. The structural and chemical properties of modified membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray electron spectroscopy (XPS). The resultant PA membranes with specific surface chemistry and controlled pore size are applicable for molecular separation, cell culture, bioreactors, biosensing, drug delivery, and engineering complex composite membranes

Self-assembly of tissue spheroids on polymeric membranes.

Science.gov (United States)

Messina, Antonietta; Morelli, Sabrina; Forgacs, Gabor; Barbieri, Giuseppe; Drioli, Enrico; De Bartolo, Loredana

2017-07-01

In this study, multicellular tissue spheroids were fabricated on polymeric membranes in order to accelerate the fusion process and tissue formation. To this purpose, tissue spheroids composed of three different cell types, myoblasts, fibroblasts and neural cells, were formed and cultured on agarose and membranes of polycaprolactone (PCL) and chitosan (CHT). Membranes prepared by a phase-inversion technique display different physicochemical, mechanical and transport properties, which can affect the fusion process. The membranes accelerated the fusion process of a pair of spheroids with respect to the inert substrate. In this process, a critical role is played by the membrane properties, especially by their mechanical characteristics and oxygen and carbon dioxide mass transfer. The rate of fusion was quantified and found to be similar for fibroblast, myoblast and neural tissue spheroids on membranes, which completed the fusion within 3 days. These spheroids underwent faster fusion and maturation on PCL membrane than on agarose, the rate of fusion being proportional to the value of oxygen and carbon dioxide permeances and elastic characteristics. Consequently, tissue spheroids on the membranes expressed high biological activity in terms of oxygen uptake, making them more suitable as building blocks in the fabrication of tissues and organs. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

In situ synthesis of molecularly imprinted nanoparticles in porous support membranes using high-viscosity polymerization solvents.

Science.gov (United States)

Renkecz, Tibor; László, Krisztina; Horváth, Viola

2012-06-01

There is a growing need in membrane separations for novel membrane materials providing selective retention. Molecularly imprinted polymers (MIPs) are promising candidates for membrane functionalization. In this work, a novel approach is described to prepare composite membrane adsorbers incorporating molecularly imprinted microparticles or nanoparticles into commercially available macroporous filtration membranes. The polymerization is carried out in highly viscous polymerization solvents, and the particles are formed in situ in the pores of the support membrane. MIP particle composite membranes selective for terbutylazine were prepared and characterized by scanning electron microscopy and N₂ porosimetry. By varying the polymerization solvent microparticles or nanoparticles with diameters ranging from several hundred nanometers to 1 µm could be embedded into the support. The permeability of the membranes was in the range of 1000 to 20,000 Lm⁻²  hr⁻¹  bar⁻¹. The imprinted composite membranes showed high MIP/NIP (nonimprinted polymer) selectivity for the template in organic media both in equilibrium-rebinding measurements and in filtration experiments. The solid phase extraction of a mixture of the template, its analogs, and a nonrelated compound demonstrated MIP/NIP selectivity and substance selectivity of the new molecularly imprinted membrane. The synthesis technique offers a potential for the cost-effective production of selective membrane adsorbers with high capacity and high throughput. Copyright © 2012 John Wiley & Sons, Ltd.

Characterization of interactions between inclusion membrane proteins from Chlamydia trachomatis

Directory of Open Access Journals (Sweden)

Emilie eGauliard

2015-02-01

Full Text Available Chlamydiae are obligate intracellular pathogens of eukaryotes. The bacteria grow in an intracellular vesicle called an inclusion, the membrane of which is heavily modified by chlamydial proteins called Incs (Inclusion membrane proteins. Incs represent 7-10% of the genomes of Chlamydia and, given their localization at the interface between the host and the pathogen, likely play a key role in the development and pathogenesis of the bacterium. However, their functions remain largely unknown. Here, we characterized the interaction properties between various Inc proteins of C. trachomatis, using a bacterial two-hybrid (BACTH method suitable for detecting interactions between integral membrane proteins. To validate this approach, we first examined the oligomerization properties of the well-characterized IncA protein and showed that both the cytoplasmic domain and the transmembrane region independently contribute to IncA oligomerization. We then analyzed a set of Inc proteins and identified novel interactions between these components. Two small Incs, IncF and Ct222, were found here to interact with many other Inc proteins and may thus represent interaction nodes within the inclusion membrane. Our data suggest that the Inc proteins may assemble in the membrane of the inclusion to form specific multi-molecular complexes in an hierarchical and temporal manner. These studies will help to better define the putative functions of the Inc proteins in the infectious process of Chlamydia.

Method of preparing water purification membranes. [polymerization of allyl amine as thin films in plasma discharge

Science.gov (United States)

Hollahan, J. R.; Wydeven, T. J., Jr. (Inventor)

1974-01-01

Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes.

Developing thin-film-composite forward osmosis membranes on the PES/SPSf substrate through interfacial polymerization

KAUST Repository

Wang, Kaiyu; Chung, Tai Shung Neal; Amy, Gary L.

2011-01-01

A new scheme has been developed to fabricate high-performance forward osmosis (FO) membranes through the interfacial polymerization reaction on porous polymeric supports. p-Phenylenediamine and 1,3,5-trimesoylchloride were adopted as the monomers

Influence of nonionic surfactants on the potentiometric response of hydrogen ion-selective polymeric membrane electrodes.

Science.gov (United States)

Espadas-Torre, C; Bakker, E; Barker, S; Meyerhoff, M E

1996-05-01

The influence of poly(ethylene oxide)-based nonionic surfactants (i.e., Triton X-100 and Brij 35) in the sample phase on the response properties of hydrogen ion-selective polymeric membrane electrodes containing mobile (lipophilic amines) or covalently bound (aminated-poly-(vinyl chloride)) hydrogen ion carriers is reported. In the presence of these nonionic surfactants, membrane electrode response toward interfering cation activity (e.g., Na+) in the sample phase is increased substantially and the pH measuring range shortened. The degree of cation interference for pH measurements is shown to correlate with the basicity of the hydrogen ion carrier doped within the membrane phase. The observed deterioration in selectivity arises from the partitioning of the surfactant into the membrane and concomitant extraction of metal cations by the surfactants in the organic phase. The effect of nonionic surfactants on pH electrodes prepared with aminated-PVC membranes is shown to be more complex, with additional large shifts in EMF values apparently arising from multidentate interactions between the surfactant molecules and the polymeric amine in the membrane, leading to a change in the apparent pKa values for the amine sites. The effects induced by nonionic surfactants on the EMF response function of hydrogen ion-selective polymeric membrane electrodes are modeled, and experimental results are shown to correlate well with theoretical predictions.

Synthesis of modified polymer inclusion membranes for photo-electrodeposition of cadmium using polarized electrodes

Energy Technology Data Exchange (ETDEWEB)

Yahia Cherif, Asma [Laboratory of Hydrometallurgy and Inorganic Molecular Chemistry, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria); Arous, Omar, E-mail: omararous@yahoo.fr [Laboratory of Hydrometallurgy and Inorganic Molecular Chemistry, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria); Center of Research in Physical and Chemical Analysis CRAPC, BP 248 Algiers, RP 16004, Algiers (Algeria); Amara, Mourad [Laboratory of Hydrometallurgy and Inorganic Molecular Chemistry, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria); Omeiri, Said [Center of Research in Physical and Chemical Analysis CRAPC, BP 248 Algiers, RP 16004, Algiers (Algeria); Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria); Kerdjoudj, Hacene [Laboratory of Hydrometallurgy and Inorganic Molecular Chemistry, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria); Trari, Mohamed [Laboratory of Storage and Valorization of Renewable Energies, Faculty of Chemistry, USTHB, BP 32 El Alia, 16111, Algiers (Algeria)

2012-08-15

Highlights: Black-Right-Pointing-Pointer Homogeneous PIM membranes containing water soluble polymers have been obtained under new experimental conditions. Black-Right-Pointing-Pointer Photoelectrodeposition of 'Cd' has been carried out using WO{sub 3} and CuFeO{sub 2} as electrode. Black-Right-Pointing-Pointer Using both photo-polarized electrodes enhances transference of cadmium compared to one. Black-Right-Pointing-Pointer Membrane with poly-phosphoric acid (PPA) give a rise of transferred amount of Cd. - Abstract: In this work, we have developed a novel class of polymeric inclusion membranes (PIMs) for the cations separation. The membrane is made up of cellulose triacetate modified by poly-electrolytes (poly-phosphoric acid, polyvinyl pyrolidone, polyacrylic acid, polyvinyl alcohol and poly-anetholsulfonic acid) using 2-hydroxy-5-dodecylbenzaldehyde incorporated into the polymer as carrier and tris ethyl hexyl phosphate or glycerine as plasticizers. Different PIMs are synthesized and characterized by the Fourier transform infrared, X-ray diffraction, thermal analysis and scanning electron microscopy. The influence of the membrane nature is studied using supports with different physical characteristics (porosity, thickness, hydrophobia). As application, the transport of Cd{sup 2+} using PIMs coupled with photo-electrodes is investigated. The photo-catalytic results indicate that the combined system p-CuFeO{sub 2}/membrane/n-WO{sub 3} enhances considerably the electrons transfer toward the delafossite CuFeO{sub 2}. The position of the conduction band of CuFeO{sub 2} is looked to be the key issue for the photo electrochemical Cd{sup 2+} reduction.

Modification of the poly(ethylene) terephthalate track membrane structure and surface in the plasma of non-polymerized gases

International Nuclear Information System (INIS)

Kravets, L.I.; Dmitriev, S.N.; Apel, P.Y.

1999-01-01

An investigation of the properties of poly(ethylene) terephthalate track membranes (PETTMs) treated with a plasma RF-discharge in non-polymerized gases has been performed. The influence of the plasma treatment conditions on the basic properties of the membranes has been studied. It was arranged that the effect of non-polymerized gases plasma on the PETTMs results to etching a membrane's surface layer. The membranes' pore size and the form in this case change. It is shown that it is possible to change the structure of track membranes directly by gas discharge etching

Cyanex based uranyl sensitive polymeric membrane electrodes.

Science.gov (United States)

Badr, Ibrahim H A; Zidan, W I; Akl, Z F

2014-01-01

Novel uranyl selective polymeric membrane electrodes were prepared using three different low-cost and commercially available Cyanex extractants namely, bis(2,4,4-trimethylpentyl) phosphinic acid [L1], bis(2,4,4-trimethylpentyl) monothiophosphinic acid [L2] and bis(2,4,4-trimethylpentyl) dithiophosphinic acid [L3]. Optimization and performance characteristics of the developed Cyanex based polymer membrane electrodes were determined. The influence of membrane composition (e.g., amount and type of ionic sites, as well as type of plasticizer) on potentiometric responses of the prepared membrane electrodes was studied. Optimized Cyanex-based membrane electrodes exhibited Nernstian responses for UO₂(2+) ion over wide concentration ranges with fast response times. The optimized membrane electrodes based on L1, L2 and L3 exhibited Nernstian responses towards uranyl ion with slopes of 29.4, 28.0 and 29.3 mV decade(-1), respectively. The optimized membrane electrodes based on L1-L3 showed detection limits of 8.3 × 10(-5), 3.0 × 10(-5) and 3.3 × 10(-6) mol L(-1), respectively. The selectivity studies showed that the optimized membrane electrodes exhibited high selectivity towards UO₂(2+) ion over large number of other cations. Membrane electrodes based on L3 exhibited superior potentiometric response characteristics compared to those based on L1 and L2 (e.g., widest linear range and lowest detection limit). The analytical utility of uranyl membrane electrodes formulated with Cyanex extractant L3 was demonstrated by the analysis of uranyl ion in different real samples for nuclear safeguards verification purposes. The results obtained using direct potentiometry and flow-injection methods were compared with those measured using the standard UV-visible and inductively coupled plasma spectroscopic methods. © 2013 Published by Elsevier B.V.

Salt Rejection of Non-Ionic Polymeric Membranes

DEFF Research Database (Denmark)

Bo, P.; Stannett, V.

1976-01-01

A modified solution-diffusion model for the description of salt and water transport through homogeneous membranes is introduced. It is compared with the current solution-diffusion model and the combined flow-diffusion model for the description of transport under reverse osmosis conditions....... The advantage of the modified description over the current solution-diffusion model is the inclusion of a salt-water coupling transport coefficient which allows the description to be extended to membranes of high water permeability (high water content). The advantage of the modified solution-diffusion model...

Concentrated emulsion pathway to novel composite polymeric membranes and their use in pervaporation

Energy Technology Data Exchange (ETDEWEB)

Ruckenstein, E.; Sun, F. [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemical Engineering

1995-10-01

Pervaporation is becoming recognized as an energy-efficient alternative to distillation and other separation methods of liquid mixtures, especially in cases in which the traditional separation techniques are not efficient, such as the separation of azeotropic mixtures, close-boiling-point components, isomeric components, and recovery or removal of trace organic substances from aqueous solutions. Novel composite polymeric membranes have been prepared, using concentrated emulsions as precursors, and employed in the pervaporation of various liquid mixtures. In order to improve the stability of the concentrated emulsion, the hydrophilicity and/or the hydrophobicity of the phases involved must be increased by replacing them with their solutions in water and/or in a hydrocarbon, respectively. Another possibility of improving the stability is to increase the viscosity of the phases, by partial polymerization of one or both phases before preparing the concentrated emulsion. The emulsion gel was subsequently transformed into a polymer composite by polymerizing both phases. The dispersed phase should be selected to yield a hydrophobic (hydrophilic) polymer which is compatible with the components selected for separation and incompatible with the other components, while the continuous phase should be selected to yield a hydrophilic (hydrophobic) polymer which is incompatible with all of the components of the mixture, and thus it can ensure the integrity of the membrane. As examples, several composite polymeric membranes were designed, prepared, and employed in the separation by pervaporation of water-ethanol,aromatics-paraffinics, and aromatics-alcohol mixtures.

Complexation-Induced Phase Separation: Preparation of Metal-Rich Polymeric Membranes

KAUST Repository

Villalobos Vazquez de la Parra, Luis Francisco

2017-08-01

The majority of state-of-the-art polymeric membranes for industrial or medical applications are fabricated by phase inversion. Complexation induced phase separation (CIPS)—a surprising variation of this well-known process—allows direct fabrication of hybrid membranes in existing facilities. In the CIPS process, a first step forms the thin metal-rich selective layer of the membrane, and a succeeding step the porous support. Precipitation of the selective layer takes place in the same solvent used to dissolve the polymer and is induced by a small concentration of metal ions. These ions form metal-coordination-based crosslinks leading to the formation of a solid skin floating on top of the liquid polymer film. A subsequent precipitation in a nonsolvent bath leads to the formation of the porous support structure. Forming the dense layer and porous support by different mechanisms while maintaining the simplicity of a phase inversion process, results in unprecedented control over the final structure of the membrane. The thickness and morphology of the dense layer as well as the porosity of the support can be controlled over a wide range by manipulating simple process parameters. CIPS facilitates control over (i) the thickness of the dense layer throughout several orders of magnitude—from less than 15 nm to more than 6 μm, (ii) the type and amount of metal ions loaded in the dense layer, (iii) the morphology of the membrane surface, and (iv) the porosity and structure of the support. The nature of the CIPS process facilitates a precise loading of a high concentration of metal ions that are located in only the top layer of the membrane. Moreover, these metal ions can be converted—during the membrane fabrication process—to nanoparticles or crystals. This simple method opens up fascinating possibilities for the fabrication of metal-rich polymeric membranes with a new set of properties. This dissertation describes the process in depth and explores promising

Polymeric hollow fiber membranes for bioartificial organs and tissue engineering applications

NARCIS (Netherlands)

Diban-Ibrahim Gomez, Nazely; Stamatialis, Dimitrios

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

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

KAUST Repository

Sun, Shipeng; Chung, Neal Tai-Shung

2013-01-01

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.

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

Science.gov (United States)

Sun, Shi-Peng; Chung, Tai-Shung

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/m(2), which is equivalent to 13.72 W/m(2) 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.

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.

Cell membrane-inspired polymeric micelles as carriers for drug delivery.

Science.gov (United States)

Liu, Gongyan; Luo, Quanqing; Gao, Haiqi; Chen, Yuan; Wei, Xing; Dai, Hong; Zhang, Zongcai; Ji, Jian

2015-03-01

In cancer therapy, surface engineering of drug delivery systems plays an essential role in their colloidal stability, biocompatibility and prolonged blood circulation. Inspired by the cell membrane consisting of phospholipids and glycolipids, a zwitterionic phosphorylcholine functionalized chitosan oligosaccharide (PC-CSO) was first synthesized to mimic the hydrophilic head groups of those amphipathic lipids. Then hydrophobic stearic acid (SA) similar to lipid fatty acids was grafted onto PC-CSO to form amphiphilic PC-CSO-SA copolymers. Cell membrane-mimetic micelles with a zwitterionic surface and a hydrophobic SA core were prepared by the self-assembly of PC-CSO-SA copolymers, showing excellent stability under extreme conditions including protein containing media, high salt content or a wide pH range. Doxorubicin (DOX) was successfully entrapped into polymeric micelles through the hydrophobic interaction between DOX and SA segments. After fast internalization by cancer cells, sustained drug release from micelles to the cytoplasm and nucleus was achieved. This result suggests that these biomimetic polymeric micelles may be promising drug delivery systems in cancer therapy.

A new concept in polymeric thin-film composite nanofiltration membranes with antibacterial properties.

Science.gov (United States)

Mollahosseini, Arash; Rahimpour, Ahmad

2013-01-01

A new, thin film, biofouling resistant, nanofiltration (NF) membrane was fabricated with two key characteristics, viz. a low rate of silver (Ag) release and long-lasting antibacterial properties. In the new approach, nanoparticles were embedded completely in a polymeric thin-film layer. A comparison was made between the new thin-film composite (TFC), NF membrane and thin-film nanocomposite (TFN), and antibacterial NF membranes. Both types of NF membrane were fabricated by interfacial polymerization on a polysulphone sublayer using m-phenylenediamine and trimesoyl chloride as an amine monomer and an acid chloride monomer, respectively. Energy dispersive X-ray (EDX) microanalysis demonstrated the presence of Ag nanoparticles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the cross-sectional and surface morphological properties of the NF membranes. Permeability and salt rejection were tested using a dead-end filtration cell. Ag leaching from the membranes was measured using inductively coupled mass spectrometry (ICP-MS). Morphological studies showed that the TFC NF membranes had better thin-film formation (a more compact structure and a smoother surface) than TFN NF membranes. Performance experiments on TFC NF membranes revealed that permeability was good, without sacrificing salt rejection. The antibacterial properties of the fabricated membranes were tested using the disk diffusion method and viable plate counts. The antibiofouling properties of the membranes were examined by measuring the quantity of bacterial cells released from the biofilm formed (as a function of the amount of biofilm present). A more sensitive surface was observed compared to that of a typical antibacterial NF membrane. The Ag leaching rates were low, which will likely result in long-lasting antibacterial and biofouling resistant properties.

Improved antifouling potential of polyether sulfone polymeric membrane containing silver nanoparticles: self-cleaning membranes.

Science.gov (United States)

Rana, Sidra; Nazar, Umair; Ali, Jafar; Ali, Qurat Ul Ain; Ahmad, Nasir M; Sarwar, Fiza; Waseem, Hassan; Jamil, Syed Umair Ullah

2018-06-01

A new strategy to enhance the antifouling potential of polyether sulfone (PES) membrane is presented. Chemically synthesized silver nanoparticles (AgNPs) were used to prepare a mixed-matrix PES membrane by the phase inversion technique. Primarily, AgNPs synthesis was confirmed by surface plasmon resonance at 410-430 nm using UV-Visible spectroscopy. X-ray diffraction analysis revealed that AgNPs were crystalline with a diameter of 21 ± 2 nm. Furthermore, PES membranes were characterized by energy dispersive X-ray spectroscopy to confirm the incorporation of AgNPs in membranes. Hydrophilicity of the membranes was enhanced, whereas roughness, mechanical strength and biofouling were relatively reduced after embedding the AgNPs. Antibacterial potential of AgNPs was evaluated for E. coli in the disc diffusion and colony-forming unit (CFU) count method. All of the membranes were assessed for antifouling activity by filtering a control dilution (10 6  CFU/ml) of E. coli and by counting CFU. Anti-biofouling activity of the membrane was observed with different concentrations of AgNPs. Maximum reduction (66%) was observed in membrane containing 1.5% of AgNPs. The addition of antibiotic ceftriaxone enhanced the antibacterial effect of AgNPs in PES membranes. Our practicable antifouling strategy may be applied to other polymeric membranes which may pave the new way to achieve sustainable and self-cleaning membrane reactors on large scale.

Production efficiency of micellar casein concentrate using polymeric spiral-wound microfiltration membranes.

Science.gov (United States)

Beckman, S L; Zulewska, J; Newbold, M; Barbano, D M

2010-10-01

Most current research has focused on using ceramic microfiltration (MF) membranes for micellar casein concentrate production, but little research has focused on the use of polymeric spiral-wound (SW) MF membranes. A method for the production of a serum protein (SP)-reduced micellar casein concentrate using SW MF was compared with a ceramic MF membrane. Pasteurized (79°C, 18s) skim milk (1,100 kg) was microfiltered at 50°C [about 3 × concentration] using a 0.3-μm polyvinylidene fluoride spiral-wound membrane, bleed-and-feed, 3-stage process, using 2 diafiltration stages, where the retentate was diluted 1:2 with reverse osmosis water. Skim milk, permeate, and retentate were analyzed for SP content, and the reduction of SP from skim milk was determined. Theoretically, 68% of the SP content of skim milk can be removed using a single-stage 3× MF. If 2 subsequent water diafiltration stages are used, an additional 22% and 7% of the SP can be removed, respectively, giving a total SP removal of 97%. Removal of SP greater than 95% has been achieved using a 0.1-μm pore size ceramic uniform transmembrane pressure (UTP) MF membrane after a 3-stage MF with diafiltration process. One stage of MF plus 2 stages of diafiltration of 50°C skim milk using a polyvinylidene fluoride polymeric SW 0.3-μm membrane yielded a total SP reduction of only 70.3% (stages 1, 2, and 3: 38.6, 20.8, and 10.9%, respectively). The SP removal rate for the polymeric SW MF membrane was lower in all 3 stages of processing (stages 1, 2, and 3: 0.05, 0.04, and 0.03 kg/m(2) per hour, respectively) than that of the comparable ceramic UTP MF membrane (stages 1, 2, and 3: 0.30, 0.11, and 0.06 kg/m(2) per hour, respectively), indicating that SW MF is less efficient at removing SP from 50°C skim milk than the ceramic UTP system. To estimate the number of steps required for the SW system to reach 95% SP removal, the third-stage SP removal rate (27.4% of the starting material SP content) was used to

A flexible, robust and antifouling asymmetric membrane based on ultra-long ceramic/polymeric fibers for high-efficiency separation of oil/water emulsions.

Science.gov (United States)

Wang, Kui; Yiming, Wubulikasimu; Saththasivam, Jayaprakash; Liu, Zhaoyang

2017-07-06

Polymeric and ceramic asymmetric membranes have dominated commercial membranes for water treatment. However, polymeric membranes are prone to becoming fouled, while ceramic membranes are mechanically fragile. Here, we report a novel concept to develop asymmetric membranes based on ultra-long ceramic/polymeric fibers, with the combined merits of good mechanical stability, excellent fouling resistance and high oil/water selectivity, in order to meet the stringent requirements for practical oil/water separation. The ultra-long dimensions of ceramic nanofibers/polymeric microfibers endow this novel membrane with mechanical flexibility and robustness, due to the integrated and intertwined structure. This membrane is capable of separating oil/water emulsions with high oil-separation efficiency (99.9%), thanks to its nanoporous selective layer made of ceramic nanofibers. Further, this membrane also displays superior antifouling properties due to its underwater superoleophobicity and ultra-low oil adhesion of the ceramic-based selective layer. This membrane exhibits high water permeation flux (6.8 × 10 4 L m -2 h -1 bar -1 ) at low operation pressures, which is attributed to its 3-dimensional (3D) interconnected fiber-based structure throughout the membrane. In addition, the facile fabrication process and inexpensive materials required for this membrane suggest its significant potential for industrial applications.

Heparin-mimicking multilayer coating on polymeric membrane via LbL assembly of cyclodextrin-based supramolecules.

Science.gov (United States)

Deng, Jie; Liu, Xinyue; Ma, Lang; Cheng, Chong; Shi, Wenbin; Nie, Chuanxiong; Zhao, Changsheng

2014-12-10

In this study, multifunctional and heparin-mimicking star-shaped supramolecules-deposited 3D porous multilayer films with improved biocompatibility were fabricated via a layer-by-layer (LbL) self-assembly method on polymeric membrane substrates. Star-shaped heparin-mimicking polyanions (including poly(styrenesulfonate-co-sodium acrylate; Star-PSS-AANa) and poly(styrenesulfonate-co-poly(ethylene glycol)methyl ether methacrylate; Star-PSS-EGMA)) and polycations (poly(methyl chloride-quaternized 2-(dimethylamino)ethyl methacrylate; Star-PMeDMA) were first synthesized by atom transfer radical polymerization (ATRP) from β-cyclodextrin (β-CD) based cores. Then assembly of 3D porous multilayers onto polymeric membrane surfaces was carried out by alternating deposition of the polyanions and polycations via electrostatic interaction. The surface morphology and composition, water contact angle, blood activation, and thrombotic potential as well as cell viability for the coated heparin-mimicking films were systematically investigated. The results of surface ATR-FTIR spectra and XPS spectra verified successful deposition of the star-shaped supramolecules onto the biomedical membrane surfaces; scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations revealed that the modified substrate had 3D porous surface morphology, which might have a great biological influence on the biointerface. Furthermore, systematic in vitro investigation of protein adsorption, platelet adhesion, human platelet factor 4 (PF4, indicates platelet activation), activate partial thromboplastin time (APTT), thrombin time (TT), coagulation activation (thrombin-antithrombin III complex (TAT, indicates blood coagulant)), and blood-related complement activation (C3a and C5a, indicates inflammation potential) confirmed that the heparin-mimicking multilayer coated membranes exhibited ultralow blood component activations and excellent hemocompatibility. Meanwhile, after surface coating

Polyion selective polymeric membrane-based pulstrode as a detector in flow-injection analysis.

Science.gov (United States)

Bell-Vlasov, Andrea K; Zajda, Joanna; Eldourghamy, Ayman; Malinowska, Elzbieta; Meyerhoff, Mark E

2014-04-15

A method for the detection of polyions using fully reversible polyion selective polymeric membrane type pulstrodes as detectors in a flow-injection analysis (FIA) system is examined. The detection electrode consists of a plasticized polymeric membrane doped with 10 wt % of tridodecylmethylammonium-dinonylnaphthalene sulfonate (TDMA/DNNS) ion-exchanger salt. The pulse sequence used involves a short (1 s) galvanostatic pulse, an open-circuit pulse (0.5 s) during which the EMF of the cell is measured, and a longer (15 s) potentiostatic pulse to return the membrane to its original chemical composition. It is shown that total pulse sequence times can be optimized to yield reproducible real-time detection of injected samples of protamine and heparin at up to 20 samples/h. Further, it is shown that the same membrane detector can be employed for FIA detection of both polycations at levels ≥10 μg/mL and polyanions at levels of ≥40 μg/mL by changing the direction of the galvanostatic pulse. The methodology described may also be applicable in the detection of polyionic species at low levels in other flowing configurations, such as in liquid chromatography and capillary electrophoresis.

Inflation of a Polymeric Menbrane

DEFF Research Database (Denmark)

Kristensen, Susanne B.; Larsen, Johannes R.; Hassager, Ole

1998-01-01

We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane.......We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane....

Covalent attachment of phospholipid analogous polymers to modify a polymeric membrane surface: a novel approach.

Science.gov (United States)

Xu, Zhi-Kang; Dai, Qing-Wen; Wu, Jian; Huang, Xiao-Jun; Yang, Qian

2004-02-17

A novel method for the surface modification of a microporous polypropylene membrane by tethering phospholipid analogous polymers (PAPs) is given, which includes the photoinduced graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of grafted poly-(DMAEMA) with 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes. Five 2-alkyloxy-2-oxo-1,3,2-dioxaphospholanes, containing octyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy, and octadecyloxy groups in the molecular structure, were used to fabricate the PAP-modified polypropylene membranes. The attenuated total reflectance FT-IR spectra of the original, poly(DMAEMA)-grafted, and PAP-modified membranes confirmed the chemical changes on the membrane surface. Scanning electron microscope pictures showed that, compared with the original membrane, the surface porosities ofpoly(DMAEMA)-grafted and PAP-modified membranes were somewhat reduced. Water contact angles measured by the sessile drop method on PAP-modified membranes were slightly lower than that on the original polypropylene membrane, but higher than those on poly(DMAEMA)-grafted membranes with the exception of octyloxy-containing PAP-modified membranes. However, BSA adsorption experiments indicated that the five PAP-modified membranes had a much better protein-resistant property than the original polypropylene membrane and the poly(DMAEMA)-grafted membranes. For hexadecyloxy- and octadecyloxy-containing PAP-modified membranes, almost no protein adsorption was observed when the grafting degree was above 6 wt %. It was also found that the platelet adhesion was remarkably suppressed on the PAP-modified membranes. All these results demonstrate that the described approach is an effective way to improve the surface biocompatibility for polymeric membranes.

Negatively charged polysulfone membranes with hydrophilicity and antifouling properties based on in situ cross-linked polymerization.

Science.gov (United States)

Zhu, Lijing; Song, Haiming; Zhang, Dawei; Wang, Gang; Zeng, Zhixiang; Xue, Qunji

2017-07-15

Polysulfone (PSf) membrane has been widely used in water separation and purification, although, membrane fouling is still a serious problem limiting its potential. We aim to improve the antifouling of PSf membranes via a very simple and efficient method. In this work, antifouling PSf membranes were fabricated via in situ cross-linked polymerization coupled with non-solvent induced phase separation. In brief, acrylic acid (AA) and vinyltriethoxysilane (VTEOS) were copolymerized in PSf solution, then directly casted into membranes without purification. With the increase of monomers concentration, the morphology of the as-cast membranes changed from a finger-like morphology to a fully sponge-like structure due to the increased viscosity and decreased precipitation rate of the polymer solutions. Meanwhile, the hydrophilicity and electronegativity of modified membranes were highly improved leading to inhibited protein adsorption and improved antifouling property. Furthermore, in order to further find out the different roles player by AA and VTESO, the modified membrane without VTEOS was prepared and characterized. The results indicated that AA is more effective in the membrane hydrophilicity improvement, VTEOS is more crucial to improve membrane stability. This work provides valuable guidance for fabricating PSf membranes with hydrophilicity and antifouling property via in situ cross-linked polymerization. Copyright © 2017 Elsevier Inc. All rights reserved.

Impact of PAC Fines in Fouling of Polymeric and Ceramic Low-Pressure Membranes for Drinking Water Treatment

Science.gov (United States)

Oligny, Laurent; Bérubé, Pierre R.; Barbeau, Benoit

2016-01-01

This study assessed the issue of membrane fouling in a Hybrid Membrane Process (HMP) due to the export of powdered activated carbon (PAC) fines from a pretreatment contactor. Two parallel pilot-scale ceramic and polymeric membranes were studied. Reversible and irreversible foulings were measured following three cleaning procedures: Physical backwashing (BW), chemically enhanced backwashing (CEB) and Clean-in-Place (CIP). The impacts on fouling of membrane type, operation flux increase and the presence/absence of the PAC pretreatment were investigated. Membranes without pretreatment were operated in parallel as a control. In addition, CIP washwaters samples were analyzed to measure organic and inorganic foulants removed from the membranes. It was observed that for the polymeric membranes, fouling generally increased with the presence of the PAC pretreatment because of the export of fines. On the contrary, the ceramic membranes were not significantly impacted by their presence. The analysis of CIP washwaters showed a greater total organic carbon (TOC) content on membranes with a PAC pretreatment while no similar conclusion could be made for inorganic foulants. PMID:27399788

Impact of PAC Fines in Fouling of Polymeric and Ceramic Low-Pressure Membranes for Drinking Water Treatment.

Science.gov (United States)

Oligny, Laurent; Bérubé, Pierre R; Barbeau, Benoit

2016-07-07

This study assessed the issue of membrane fouling in a Hybrid Membrane Process (HMP) due to the export of powdered activated carbon (PAC) fines from a pretreatment contactor. Two parallel pilot-scale ceramic and polymeric membranes were studied. Reversible and irreversible foulings were measured following three cleaning procedures: Physical backwashing (BW), chemically enhanced backwashing (CEB) and Clean-in-Place (CIP). The impacts on fouling of membrane type, operation flux increase and the presence/absence of the PAC pretreatment were investigated. Membranes without pretreatment were operated in parallel as a control. In addition, CIP washwaters samples were analyzed to measure organic and inorganic foulants removed from the membranes. It was observed that for the polymeric membranes, fouling generally increased with the presence of the PAC pretreatment because of the export of fines. On the contrary, the ceramic membranes were not significantly impacted by their presence. The analysis of CIP washwaters showed a greater total organic carbon (TOC) content on membranes with a PAC pretreatment while no similar conclusion could be made for inorganic foulants.

Impact of PAC Fines in Fouling of Polymeric and Ceramic Low-Pressure Membranes for Drinking Water Treatment

Directory of Open Access Journals (Sweden)

Laurent Oligny

2016-07-01

Full Text Available This study assessed the issue of membrane fouling in a Hybrid Membrane Process (HMP due to the export of powdered activated carbon (PAC fines from a pretreatment contactor. Two parallel pilot-scale ceramic and polymeric membranes were studied. Reversible and irreversible foulings were measured following three cleaning procedures: Physical backwashing (BW, chemically enhanced backwashing (CEB and Clean-in-Place (CIP. The impacts on fouling of membrane type, operation flux increase and the presence/absence of the PAC pretreatment were investigated. Membranes without pretreatment were operated in parallel as a control. In addition, CIP washwaters samples were analyzed to measure organic and inorganic foulants removed from the membranes. It was observed that for the polymeric membranes, fouling generally increased with the presence of the PAC pretreatment because of the export of fines. On the contrary, the ceramic membranes were not significantly impacted by their presence. The analysis of CIP washwaters showed a greater total organic carbon (TOC content on membranes with a PAC pretreatment while no similar conclusion could be made for inorganic foulants.

Developing thin-film-composite forward osmosis membranes on the PES/SPSf substrate through interfacial polymerization

KAUST Repository

Wang, Kaiyu

2011-04-22

A new scheme has been developed to fabricate high-performance forward osmosis (FO) membranes through the interfacial polymerization reaction on porous polymeric supports. p-Phenylenediamine and 1,3,5-trimesoylchloride were adopted as the monomers for the in-situ polycondensation reaction to form a thin aromatic polyamide selective layer of 150 nm in thickness on the substrate surface, a lab-made polyethersulfone (PES)/sulfonated polysulfone (SPSf)-alloyed porous membrane with enhanced hydrophilicity. Under FO tests, the FO membrane achieved a higher water flux of 69.8 LMH when against deionized water and 25.2 LMH when against a model 3.5 wt % NaCl solution under 5.0 M NaCl as the draw solution in the pressure-retarded osmosis mode. The PES/SPSf thin-film-composite (TFC)-FO membrane has a smaller structural parameter S of 238 μm than those reported data. The morphology and topology of substrates and TFC-FO membranes have been studied by means of atomic force microscopy and scanning electronic microscopy. © 2011 American Institute of Chemical Engineers (AIChE).

Deposition of polymeric perfluored thin films in proton ionic membranes by plasma processes

International Nuclear Information System (INIS)

Polak, Peter Lubomir; Mousinho, Ana Paula; Ordonez, Nelson; Silva Zambom, Luis da; Mansano, Ronaldo Domingues

2007-01-01

In this work the surfaces of polymeric membranes based on Nafion (proton conducting material), used in proton exchange membranes fuel cells (PEMFC) had been modified by plasma deposition of perfluored polymers, in order to improve its functioning in systems of energy generation (fuel cells). The deposition increases the chemical resistance of the proton ionic polymers without losing the electrical properties. The processing of the membranes also reduces the permeability of the membranes to the alcohols (methanol and ethanol), thus preventing poisoning of the fuel cell. The processing of the membranes of Nafion was carried through in a system of plasma deposition using a mixture of CF 4 and H 2 gases. The plasma processing was made mainly to increase the chemical resistance and result in hydrophobic surfaces. The Fourier transformed infrared (FTIR) technique supplies a spectrum with information about the CF n bond formation. Through the Rutherford back scattering (RBS) technique it was possible to verify the deposition rate of the polymeric layer. The plasma process with composition of 60% of CF 4 and 40% of H 2 presented the best deposition rate. By the spectrum analysis for the optimized configuration, it was possible to verify that the film deposition occurred with a thickness of 90 nm, and fluorine concentration was nearly 30%. Voltammetry made possible to verify that the fluorination increases the membranes chemical resistance, improving the stability of Nafion, becoming an attractive process for construction of fuel cells

Polymeric membranes modulate human keratinocyte differentiation in specific epidermal layers.

Science.gov (United States)

Salerno, Simona; Morelli, Sabrina; Giordano, Francesca; Gordano, Amalia; Bartolo, Loredana De

2016-10-01

In vitro models of human bioengineered skin substitutes are an alternative to animal experimentation for testing the effects and toxicity of drugs, cosmetics and pollutants. For the first time specific and distinct human epidermal strata were engineered by using membranes and keratinocytes. To this purpose, biodegradable membranes of chitosan (CHT), polycaprolactone (PCL) and a polymeric blend of CHT-PCL were prepared by phase-inversion technique and characterized in order to evaluate their morphological, physico-chemical and mechanical properties. The capability of membranes to modulate keratinocyte differentiation inducing specific interactions in epidermal membrane systems was investigated. The overall results demonstrated that the membrane properties strongly influence the cell morpho-functional behaviour of human keratinocytes, modulating their terminal differentiation, with the creation of specific epidermal strata or a fully proliferative epidermal multilayer system. In particular, human keratinocytes adhered on CHT and CHT-PCL membranes, forming the structure of the epidermal top layers, such as the corneum and granulosum strata, characterized by withdrawal or reduction from the cell cycle and cell proliferation. On the PCL membrane, keratinocytes developed an epidermal basal lamina, with high proliferating cells that stratified and migrated over time to form a complete differentiating epidermal multilayer system. Copyright © 2016 Elsevier B.V. All rights reserved.

Pharmacological aspects of release from microcapsules - from polymeric multilayers to lipid membranes.

Science.gov (United States)

Wuytens, Pieter; Parakhonskiy, Bogdan; Yashchenok, Alexey; Winterhalter, Mathias; Skirtach, Andre

2014-10-01

This review is devoted to pharmacological applications of principles of release from capsules to overcome the membrane barrier. Many of these principles were developed in the context of polymeric multilayer capsule membrane modulation, but they are also pertinent to liposomes, polymersomes, capsosomes, particles, emulsion-based carriers and other carriers. We look at these methods from the physical, chemical or biological driving mechanisms point of view. In addition to applicability for carriers in drug delivery, these release methods are significant for another area directly related to pharmacology - modulation of the permeability of the membranes and thus promoting the action of drugs. Emerging technologies, including ionic current monitoring through a lipid membrane on a nanopore, are also highlighted. Copyright © 2014 Elsevier Ltd. All rights reserved.

Research in Water Permeability of Poly(ethylene) Terephthalate Track Membranes Modified by Polymerization of Dimethylaniline under the Action of Direct Current Discharge

CERN Document Server

Kravets, L I; Drachev, A I

2004-01-01

The properties of poly(ethylene) terephthalate track membranes modified by polymerization of dimethylaniline in a discharge of direct current are investigated. The influence of conditions of plasma treatment on the basic characteristics of the membranes (pore size, wettability, surface charge, water permeability) is studied. It is shown that under the action of discharge, a polymeric layer is formed on the membrane surface that can swell in solutions with low pH values. It has been found that the degree of the swelling stipulated by the conformation transfer of macromolecules of the deposited polymeric layer depends upon the size of relative magnification of the mass of the membrane during its plasma treatment. It is also shown that the obtained membranes can reversibly react to changing the pH of solution and applied pressure.

Preparation of antifouling ultrafiltration membranes via irradiation induced graft polymerization technique

International Nuclear Information System (INIS)

Deng Bo; Liu Zhognying; Lu Xiaofeng; Li Jingye; Yang Xuanxuan; Yu Ming; Zhang Bowu

2010-01-01

PVDF powders were irradiated in air at dose of 15 kGy by using gamma-rays. Macromolecular peroxides transformed from free radicals in the irradiated PVDF powders in air can be preserved for long-term at appropriate temperature stably. By mixing acrylic monomers with irradiated PVDF powders then the graft polymerization can be initiated by heating. Then a series of hydrophilic ultrafiltration (UF) membranes were fabricated by dissolving the PVDF-g-PAAc powders in the NMP under phase inversion method. The antifouling performances of UF membranes cast from virgin and grafted PVDF powders were compared. (authors)

Efficiency of serum protein removal from skim milk with ceramic and polymeric membranes at 50 degrees C.

Science.gov (United States)

Zulewska, J; Newbold, M; Barbano, D M

2009-04-01

Raw milk (2,710 kg) was separated at 4 degrees C, the skim milk was pasteurized (72 degrees C, 16 s), split into 3 batches, and microfiltered using pilot-scale ceramic uniform transmembrane pressure (UTP; Membralox model EP1940GL0.1microA, 0.1 microm alumina, Pall Corp., East Hills, NY), ceramic graded permeability (GP; Membralox model EP1940GL0.1microAGP1020, 0.1 microm alumina, Pall Corp.), and polymeric spiral-wound (SW; model FG7838-OS0x-S, 0.3 microm polyvinylidene fluoride, Parker-Hannifin, Process Advanced Filtration Division, Tell City, IN) membranes. There were differences in flux among ceramic UTP, ceramic GP, and polymeric SW microfiltration membranes (54.08, 71.79, and 16.21 kg/m2 per hour, respectively) when processing skim milk at 50 degrees C in a continuous bleed-and-feed 3x process. These differences in flux among the membranes would influence the amount of membrane surface area required to process a given volume of milk in a given time. Further work is needed to determine if these differences in flux are maintained over longer processing times. The true protein contents of the microfiltration permeates from UTP and GP membranes were higher than from SW membranes (0.57, 0.56, and 0.38%, respectively). Sodium-dodecyl-sulfate-PAGE gels for permeates revealed a higher casein proportion in GP and SW permeate than in UTP permeate, with the highest passage of casein through the GP membrane under the operational conditions used in this study. The slight cloudiness of the permeates produced using the GP and SW systems may have been due to the presence of a small amount of casein, which may present an obstacle in their use in applications when clarity is an important functional characteristic. More beta-lactoglobulin passed through the ceramic membranes than through the polymeric membrane. The efficiency of removal of serum proteins in a continuous bleed-and-feed 3x process at 50 degrees C was 64.40% for UTP, 61.04% for GP, and 38.62% for SW microfiltration

Preparation of Zeolitic Imidazolate Framework-8 (ZIF-8) Membrane on Porous Polymeric Support via Contra-Diffusion Method

KAUST Repository

Tan, Xiaoyu

2016-05-18

In the last decade, many attempts were made to put metal organic frameworks (MOFs) in industrial applications, but most of these efforts weren’t successfully. As one of the few MOFs produced on industrial scale, ZIF-8 has interesting pore size, huge internal surface area and great thermal and chemical stability. Therefore, ZIF-8 might become the first MOF, which will be applied in industrial separation processes. In this thesis, a synthesis study is presented, which leads to a cheap and convenient way to
fabricate defect-free and thin ZIF-8 membranes on porous polymeric supports showing high selectivity and high gas permeance. The ZIF-8 layers were produced via a contra-diffusion method. Several polymeric membranes were employed as support in this study, such as PAN, PEI, PSU, PA and PTSC. We studied the influence of the polymeric support properties for the ZIF-8 membrane preparation and optimized the ZIF-8 preparation conditions. The ZIF-8 membranes were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). For gas permeation test, we chose a Wicke-Kallenbach apparatus to measure membrane’s gas permeance and selectivity. One of the best ZIF-8 membranes exhibited a hydrogen permeance of 3.45 × 10-8 mol m-2 s-1 Pa-1 and
an ideal selectivity of hydrogen over propane of about 500.

Ultrathin Polyamide Membranes Fabricated from Free-Standing Interfacial Polymerization: Synthesis, Modifications, and Post-treatment

KAUST Repository

Cui, Yue

2016-12-21

The thin film composite (TFC) membrane synthesized via interfacial polymerization is the workhorse of the prevalent membrane technologies such as nanofiltration (NF), reverse osmosis (RO), forward osmosis (FO), and pressure retarded osmosis (PRO) membranes. The polyamide selective layer usually possesses a high selectivity and permeability, making it the heart of this membrane technology. To further improve and understand its formation, with entirely excluding the effect of substrate, an ultrathin membrane which consists of only the polyamide selective layer has been fabricated via free-standing interfacial polymerization between M-phenylenediamine (MPD) and trimesoyl chloride (TMC) in this study. The influences of monomer concentration on polyamide layer formation is first examined. Different from previous studies which indicated that the variation of MPD concentration might affect the polyamide layer formation even when in excess, the MPD concentration when in excess does not affect membrane properties significantly, while increasing the TMC concentration gradually densifies the polyamide layer and enhances its transport resistance. Adding lithium bromide (LiBr) and sodium dodecyl sulfate (SDS) in MPD solutions is found to facilitate the reaction between the two phases and result in a significant improvement in water permeability. However, a high amount of additives leads to an augmentation in transport resistance. The N,N-dimethylformamide (DMF) treatment on the polyamide membrane shows pronounced improvements on water flux under FO tests and water permeability under RO tests without compromising reverse salt flux and salt rejection because the dense polyamide core stays intact. This study may offer a different perspective on membrane formation and intrinsic properties of the polyamide selective layer and provide useful insights for the development of next-generation TFC membranes.

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

Directory of Open Access Journals (Sweden)

Sagar Roy

2017-09-01

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

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

Science.gov (United States)

Roy, Sagar; Singha, Nayan Ranjan

2017-09-08

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

Biofouling of reverse osmosis membranes: effects of cleaning on biofilm microbial communities, membrane performance, and adherence of extracellular polymeric substances.

Science.gov (United States)

Al Ashhab, Ashraf; Sweity, Amer; Bayramoglu, Bihter; Herzberg, Moshe; Gillor, Osnat

2017-05-01

Laboratory-scale reverse osmosis (RO) flat-sheet systems were used with two parallel flow cells, one treated with cleaning agents and a control (ie undisturbed). The cleaning efforts increased the affinity of extracellular polymeric substances (EPS) to the RO membrane and altered the biofilm surface structure. Analysis of the membrane biofilm community composition revealed the dominance of Proteobacteria. However, within the phylum Proteobacteria, γ-Proteobacteria dominated the cleaned membrane biofilm, while β-Proteobacteria dominated the control biofilm. The composition of the fungal phyla was also altered by cleaning, with enhancement of Ascomycota and suppression of Basidiomycota. The results suggest that repeated cleaning cycles select for microbial groups that strongly attach to the RO membrane surface by producing rigid and adhesive EPS that hampers membrane performance.

Effect of polymer type on characterization and filtration performances of multi-walled carbon nanotubes (MWCNT)-COOH-based polymeric mixed matrix membranes.

Science.gov (United States)

Sengur-Tasdemir, Reyhan; Mokkapati, Venkata R S S; Koseoglu-Imer, Derya Y; Koyuncu, Ismail

2018-05-01

Multi-walled carbon nanotubes (MWCNTs) can be used for the fabrication of mixed matrix polymeric membranes that can enhance filtration perfomances of the membranes by modifying membrane surface properties. In this study, detailed characterization and filtration performances of MWCNTs functionalized with COOH group, blended into polymeric flat-sheet membranes were investigated using different polymer types. Morphological characterization was carried out using atomic force microscopy, scanning electron microscopy and contact angle measurements. For filtration performance tests, protein, dextran, E. coli suspension, Xanthan Gum and real activated sludge solutions were used. Experimental data and analyses revealed that Polyethersulfone (PES) + MWCNT-COOH mixed matrix membranes have superior performance abilities compared to other tested membranes.

Development of novel ion-exchange membranes for electrodialysis of seawater by electron-beam-induced graft polymerization (4). Polymeric structures of cation-exchange membranes based on nylon-6 film

International Nuclear Information System (INIS)

Miyazawa, Tadashi; Asari, Yuki; Miyoshi, Kazuyoshi; Umeno, Daisuke; Saito, Kyoichi; Nagatani, Takeshi; Yoshikawa, Naohito; Motokawa, Ryuhei; Koizumi, Satoshi

2010-01-01

Cation-exchange membranes containing a sulfonic acid group were prepared by electron-beam-induced graft polymerization of sodium styrene sulfonate (SSS) onto a nylon-6 film with a thickness of 25 μm. The lamella sizes and lamella-to-lamella intervals of the resultant cation-exchange membranes (SSS membranes) were evaluated by X-ray diffraction (XRD) analysis and small-angle neutron scattering (SANS), respectively. With increasing degrees of grafting, the lamella size decreased, whereas the lamella-to-lamella interval increased. This can be explained by that the poly-SSS chain grafted to the periphery of the lamella of nylon 6 partially destroys the lamella and invades the amorphous domain among the lamella. The SSS membrane with a degree of grafting of 150% exhibited a similar performance in the electrodialysis of 0.5 M sodium chloride as a current cation-exchange membrane and possessed the lamella sizes and lamella-to-lamella intervals of 7.6 and 13 nm, respectively. (author)

Poly-thiosemicarbazide/gold nanoparticles catalytic membrane: In-situ growth of well-dispersed, uniform and stable gold nanoparticles in a polymeric membrane

KAUST Repository

Villalobos, Luis Francisco; Neelakanda, Pradeep; Karunakaran, Madhavan; Cha, Dong Kyu; Peinemann, Klaus-Viktor

2014-01-01

This work presents a method that achieves the highest loading, published so far, of non-agglomerated and well-distributed gold nanoparticles (AuNPs) inside a polymeric membrane. The method uses poly-thiosemicarbazide (PTSC) as the starting material

Synthesis of robust and high-performance aquaporin-based biomimetic membranes by interfacial polymerization-membrane preparation and RO performance characterization

DEFF Research Database (Denmark)

Zhao, Yang; Qiu, Changquan; Li, Xuesong

2012-01-01

-free ABMs that can be easily scaled up. In the current study, a thin film composite (TFC) ABM was prepared by the interfacial polymerization method, where AquaporinZ-containing proteoliposomes were added to the m-phenylene-diamine aqueous solution. Control membranes, either without aquaporins......Aquaporins are water channel proteins with excellent water permeability and solute rejection, which makes them promising for preparing high-performance biomimetic membranes. Despite the growing interest in aquaporin-based biomimetic membranes (ABMs), it is challenging to produce robust and defect...... or with inactive (mutant) aquaporins, were also similarly prepared. The separation performance of these membranes was evaluated by cross-flow reverse osmosis (RO) tests. Compared to the controls, the active ABM achieved significantly higher water permeability (∼4L/m2hbar) with comparable NaCl rejection (∼97...

SORPTION, DIFFUSION AND PERMEATION OF 1,1,1- TRICHLOROETHANE THROUGH ADSORBENT-FILLED POLYMERIC MEMBRANES

Science.gov (United States)

Addition of hydrophobic absorbents such as activated carbon into polymeric mebranes increased the sorption capacity for 1,1,1-trichloroethane premeability of the mebranes used in the Pervaporation mode. Water permeability also increased for all filled membranes due to increased w...

Improved PVDF membrane performance by doping extracellular polymeric substances of activated sludge.

Science.gov (United States)

Guan, Yan-Fang; Huang, Bao-Cheng; Qian, Chen; Wang, Long-Fei; Yu, Han-Qing

2017-04-15

Polyvinylidene fluoride (PVDF) membrane has been widely applied in water and wastewater treatment because of its high mechanical strength, thermal stability and chemical resistance. However, the hydrophobic nature of PVDF membrane makes it readily fouled, substantially reducing water flux and overall membrane rejection ability. In this work, an in-situ blending modifier, i.e., extracellular polymeric substances (EPS) from activated sludge, was used to enhance the anti-fouling ability of PVDF membrane. Results indicate that the pure water flux of the membrane and its anti-fouling performance were substantially improved by blending 8% EPS into the membrane. By introducing EPS, the membrane hydrophilicity was increased and the cross section morphology was changed when it interacted with polyvinl pyrrolidone, resulting in the formation of large cavities below the finger-like pores. In addition, the fraction of pores with a size of 100-500 nm increased, which was also beneficial to improving membrane performance. Surface thermodynamic calculations indicate the EPS-functionalized membrane had a higher cohesion free energy, implying its good pollutant rejection and anti-fouling ability. This work provides a simple, efficient and cost-effective method to improve membrane performance and also extends the applications of EPS. Copyright © 2017 Elsevier Ltd. All rights reserved.

The use of radiation-induced graft polymerization for modification of polymer track membranes

International Nuclear Information System (INIS)

Shtanko, N.I.; Kabanov, V.Ya.; Apel, P.Yu.; Yoshida, M.

1999-01-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called 'intelligent' materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2 ) and then exposed to the γ-rays from a 60 Co source. The transport properties of the

The use of radiation-induced graft polymerization for modification of polymer track membranes

Science.gov (United States)

Shtanko, N. I.; Kabanov, V. Ya.; Apel, P. Yu.; Yoshida, M.

1999-05-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called "intelligent" materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2) and then exposed to the γ-rays from a 60Co source. The transport properties of the grafted

The relevance of polymeric synthetic membranes in topical formulation assessment and drug diffusion study.

Science.gov (United States)

Ng, Shiow-Fern; Rouse, Jennifer J; Sanderson, Francis D; Eccleston, Gillian M

2012-03-01

Synthetic membranes are composed of thin sheets of polymeric macromolecules that can control the passage of components through them. Generally, synthetic membranes used in drug diffusion studies have one of two functions: skin simulation or quality control. Synthetic membranes for skin simulation, such as the silicone-based membranes polydimethylsiloxane and Carbosil, are generally hydrophobic and rate limiting, imitating the stratum corneum. In contrast, synthetic membranes for quality control, such as cellulose esters and polysulfone, are required to act as a support rather than a barrier. These synthetic membranes also often contain pores; hence, they are called porous membranes. The significance of Franz diffusion studies and synthetic membranes in quality control studies involves an understanding of the fundamentals of synthetic membranes. This article provides a general overview of synthetic membranes, including a brief background of the history and the common applications of synthetic membranes. This review then explores the types of synthetic membranes, the transport mechanisms across them, and their relevance in choosing a synthetic membrane in Franz diffusion cell studies for formulation assessment purposes.

Dynamic Membrane Formation in Anaerobic Dynamic Membrane Bioreactors: Role of Extracellular Polymeric Substances.

Directory of Open Access Journals (Sweden)

Hongguang Yu

Full Text Available Dynamic membrane (DM formation in dynamic membrane bioreactors plays an important role in achieving efficient solid-liquid separation. In order to study the contribution of extracellular polymeric substances (EPS to DM formation in anaerobic dynamic membrane bioreactor (AnDMBR processes, EPS extraction from and re-addition to bulk sludge were carried out in short-term filtration tests. DM formation behaviors could be well simulated by cake filtration model, and sludge with EPS re-addition showed the highest resistance coefficient, followed by sludge after EPS extraction. The DM layers exhibited a higher resistance and a lower porosity for the sludge sample after EPS extraction and for the sludge with EPS re-addition. Particle size of sludge flocs decreased after EPS extraction, and changed little with EPS re-addition, which was confirmed by interaction energy analysis. Further investigations by confocal laser scanning microscopy (CLSM analysis and batch tests suggested that the removal of in-situ EPS stimulated release of soluble EPS, and re-added EPS were present as soluble EPS rather than bound EPS, which thus improved the formation of DM. The present work revealed the role of EPS in anaerobic DM formation, and could facilitate the operation of AnDMBR processes.

Fluorescent sensor systems based on nanostructured polymeric membranes for selective recognition of Aflatoxin B1.

Science.gov (United States)

Sergeyeva, Tetyana; Yarynka, Daria; Piletska, Elena; Lynnik, Rostyslav; Zaporozhets, Olga; Brovko, Oleksandr; Piletsky, Sergey; El'skaya, Anna

2017-12-01

Nanostructured polymeric membranes for selective recognition of aflatoxin B1 were synthesized in situ and used as highly sensitive recognition elements in the developed fluorescent sensor. Artificial binding sites capable of selective recognition of aflatoxin B1 were formed in the structure of the polymeric membranes using the method of molecular imprinting. A composition of molecularly imprinted polymer (MIP) membranes was optimized using the method of computational modeling. The MIP membranes were synthesized using the non-toxic close structural analogue of aflatoxin B1, ethyl-2-oxocyclopentanecarboxylate as a dummy template. The MIP membranes with the optimized composition demonstrated extremely high selectivity towards aflatoxin B1 (AFB1). Negligible binding of close structural analogues of AFB1 - aflatoxins B2 (AFB2), aflatoxin G2 (AFG2), and ochratoxin A (OTA) was demonstrated. Binding of AFB1 by the MIP membranes was investigated as a function of both type and concentration of the functional monomer in the initial monomer composition used for the membranes' synthesis, as well as sample composition. The conditions of the solid-phase extraction of the mycotoxin using the MIP membrane as a stationary phase (pH, ionic strength, buffer concentration, volume of the solution, ratio between water and organic solvent, filtration rate) were optimized. The fluorescent sensor system based on the optimized MIP membranes provided a possibility of AFB1 detection within the range 14-500ngmL -1 demonstrating detection limit (3Ϭ) of 14ngmL -1 . The developed technique was successfully applied for the analysis of model solutions and waste waters from bread-making plants. Copyright © 2017 Elsevier B.V. All rights reserved.

A facile method to align carbon nanotubes on polymeric membrane substrate

Science.gov (United States)

Zhao, Haiyang; Zhou, Zhijun; Dong, Hang; Zhang, Lin; Chen, Huanlin; Hou, Lian

2013-01-01

The alignment of carbon nanotubes (CNT) is the fundamental requirement to ensure their excellent functions but seems to be desolated in recent years. A facile method, hot-press combined with peel-off (HPPO), is introduced here, through which CNT can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The alignment of CNT keeps its orientation in a thin hybrid membrane by dip-coating cellulose acetate dope solution. It is expected that the stable alignment of CNT by HPPO would contribute to the realization of its potential applications. PMID:24326297

Membrane and inclusion body targeting of lyssavirus matrix proteins.

Science.gov (United States)

Pollin, Reiko; Granzow, Harald; Köllner, Bernd; Conzelmann, Karl-Klaus; Finke, Stefan

2013-02-01

Lyssavirus matrix proteins (M) support virus budding and have accessory functions that may contribute to host cell manipulation and adaptation to specific hosts. Here, we show that rabies virus (RABV) and European Bat Lyssavirus Type 1 (EBLV-1) M proteins differ in targeting and accumulation at cellular membranes. In contrast to RABV M, EBLV-1 M expressed from authentic EBLV-1 or chimeric RABV accumulated at the Golgi apparatus. Chimeric M proteins revealed that Golgi association depends on the integrity of the entire EBLV-1 M protein. Since RABV and EBLV-1 M differ in the use of cellular membranes for particle formation, differential membrane targeting and transport of M might determine the site of virus production. Moreover, both RABV and EBLV-1 M were for the first time detected within the nucleus and in Negri body-like inclusions bodies. Whereas nuclear M may imply hitherto unknown functions of lyssavirus M in host cell manipulation, the presence of M in inclusion bodies may correlate with regulatory functions of M in virus RNA synthesis. The data strongly support a model in which targeting of lyssavirus M proteins to distinctintracellular sites is a key determinant of diverse features in lyssavirus replication, host adaptation and pathogenesis. © 2012 Blackwell Publishing Ltd.

[Computer modeling the hydrostatic pressure characteristics of the membrane potential for polymeric membrane, separated non-homogeneous electrolyte solutions].

Science.gov (United States)

Slezak, Izabella H; Jasik-Slezak, Jolanta; Rogal, Mirosława; Slezak, Andrzej

2006-01-01

On the basis of model equation depending the membrane potential deltapsis, on mechanical pressure difference (deltaP), concentration polarization coefficient (zetas), concentration Rayleigh number (RC) and ratio concentration of solutions separated by membrane (Ch/Cl), the characteristics deltapsis = f(deltaP)zetas,RC,Ch/Cl for steady values of zetas, RC and Ch/Cl in single-membrane system were calculated. In this system neutral and isotropic polymeric membrane oriented in horizontal plane, the non-homogeneous binary electrolytic solutions of various concentrations were separated. Nonhomogeneity of solutions is results from creations of the concentration boundary layers on both sides of the membrane. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, RC and zetas.

Production of Fluconazole-Loaded Polymeric Micelles Using Membrane and Microfluidic Dispersion Devices

Directory of Open Access Journals (Sweden)

Yu Lu

2016-05-01

Full Text Available Polymeric micelles with a controlled size in the range between 41 and 80 nm were prepared by injecting the organic phase through a microengineered nickel membrane or a tapered-end glass capillary into an aqueous phase. The organic phase was composed of 1 mg·mL−1 of PEG-b-PCL diblock copolymers with variable molecular weights, dissolved in tetrahydrofuran (THF or acetone. The pore size of the membrane was 20 μm and the aqueous/organic phase volumetric flow rate ratio ranged from 1.5 to 10. Block copolymers were successfully synthesized with Mn ranging from ~9700 to 16,000 g·mol−1 and polymeric micelles were successfully produced from both devices. Micelles produced from the membrane device were smaller than those produced from the microfluidic device, due to the much smaller pore size compared with the orifice size in a co-flow device. The micelles were found to be relatively stable in terms of their size with an initial decrease in size attributed to evaporation of residual solvent rather than their structural disintegration. Fluconazole was loaded into the cores of micelles by injecting the organic phase composed of 0.5–2.5 mg·mL−1 fluconazole and 1.5 mg·mL−1 copolymer. The size of the drug-loaded micelles was found to be significantly larger than the size of empty micelles.

Potentiometric determination of trypsin using a polymeric membrane polycation-sensitive electrode based on current-controlled reagent delivery.

Science.gov (United States)

Chen, Yan; Ding, Jiawang; Qin, Wei

2012-12-01

A potentiometric biosensor for the determination of trypsin is described based on current-controlled reagent delivery. A polymeric membrane protamine-sensitive electrode with dinonylnaphthalene sulfonate as cation exchanger is used for in situ generation of protamine. Diffusion of protamine across the polymeric membrane can be controlled precisely by applying an external current. The hydrolysis catalyzed with trypsin in sample solution decreases the concentration of free protamine released at the sample-membrane interface and facilitates the stripping of protamine out of the membrane surface via the ion-exchange process with sodium ions from the sample solution, thus decreasing the membrane potential, by which the protease can be sensed potentiometrically. The influences of anodic current amplitude, current pulse duration and protamine concentration in the inner filling solution on the membrane potential response have been studied. Under optimum conditions, the proposed protamine-sensitive electrode is useful for continuous and reversible detection of trypsin over the concentration range of 0.5-5UmL(-1) with a detection limit of 0.3UmL(-1). The proposed detection strategy provides a rapid and reagentless way for the detection of protease activities and offers great potential in the homogeneous immunoassays using proteases as labels. Copyright © 2012 Elsevier B.V. All rights reserved.

A 9-vinyladenine-based molecularly imprinted polymeric membrane for the efficient recognition of plant hormone 1H-indole-3-acetic acid

International Nuclear Information System (INIS)

Chen Changbao; Chen Yanjun; Zhou Jie; Wu Chunhui

2006-01-01

9-Vinyladenine was synthesized as a novel functional monomer for molecular imprinting techniques and its structure was established with elemental analysis and 1 H NMR spectroscopy. The binding mechanism between this functional monomer 9-vinyladenine and the plant hormone 1 H-indole-3-acetic acid in acetonitrile was studied with UV-vis spectrophotometry. Based on this study, using 1 H-indole-3-acetic acid as a template molecule, a specific 9-vinyladenine-based molecularly imprinted polymeric membrane was prepared. Then, the resultant polymeric membrane morphologies were visualized with scanning electron microscopy, and the membrane permselectivity for 1 H-indole-3-acetic acid, 1 H-indole-3-butyric acid and kinetin was tested with separate experiments and competitive diffusion experiments. These results showed that the imprinted polymeric membrane prepared with 9-vinyladenine exhibited higher transport selectivity for the template molecule 1 H-indole-3-acetic acid than 1 H-indole-3-butyric acid or kinetin. The membrane prepared with 9-vinyladenine also took on higher permselectivity for 1 H-indole-3-acetic acid in comparison with the imprinted membrane made with methacrylic acid. It is predicted that the 9-vinyladenine-based molecularly imprinted membrane may be applicable to the assay of 1 H-indole-3-acetic acid or for the preparation of a molecularly imprinted polymer sensor for the analysis of 1 H-indole-3-acetic acid in plant samples

Characterization of hypothetical proteins Cpn0146, 0147, 0284 & 0285 that are predicted to be in the Chlamydia pneumoniae inclusion membrane

Directory of Open Access Journals (Sweden)

Liu Kaiyang

2007-05-01

Full Text Available Abstract Background Although more than 100 Chlamydia pneumoniae hypothetical proteins have been predicted to be inclusion membrane proteins, only a few have been experimentally demonstrated to be in the inclusion membrane. Using antibodies raised with fusion proteins, we characterized four such hypothetical proteins encoded by two gene clusters (Cpn0146-147 and Cpn0284-285 in the C. pneumoniae genome. Results Cpn0146 and 0147 were detected in the inclusion membrane while Cpn0284 and 0285 inside inclusion and mainly associated with reticulate bodies although all four proteins contain an N-terminal bi-lobed hydrophobic region, a signature motif assigned to inclusion membrane proteins. These four hypothetical proteins were only detected in cells infected with C. pneumoniae but not other chlamydial species, with Cpn0147 at 6 hours and Cpn0146, 0284 & 0285 at 24 hours after infection. Cpn0146 & 147 but not Cpn0284 and 285 co-localized with a host cell endoplasmic reticulum marker, a property known to be possessed by some chlamydial inclusion membrane proteins, when expressed in the host cell cytosol via transgenes. However, the endoplasmic reticulum localization of the C. pneumoniae inclusion membrane proteins did not result in inhibition of the subsequent C. pneumoniae infection. Conclusion The hypothetical proteins Cpn0146 & 0147 were localized in the C. pneumoniae inclusion membrane while Cpn0284 & 0285 within the inclusion although all four were predicted to be Inc proteins, suggesting the need to experimentally characterize the predicted Inc proteins.

DEVELOPMENT OF A UREA BIOSENSOR BASED ON A POLYMERIC MEMBRANE INCLUDING ZEOLITE

Directory of Open Access Journals (Sweden)

M. L HAMLAOUI

2008-06-01

+ -sensitive membrane is based on a zeolite-incorporated polymeric membrane biosensor (clinoptilolite. The sensitivity of ammonium  detection is sub-nernstian (32mV/pNH4 + but the ISFET presents a high selectivity, which is interesting for measurements in biological media. The grafting of urease to the NH4 +-sensitive membrane was permorfed by cross-linking with glutaraldehyde .The sensitivity of the urea ENFET is 15V/purea and this remains stable over 15 days with a detection limit of 3x10-5 M. Finally, in order to test feasibility of the urea biosensor for environmental applications, the remaining activity of the urease was determined after exposure to enzyme inhibiting heavy metals ions such as Hg(II.Using these urea biosensors, a detection limit of less than 5 x 10-8 M was obtained for Hg(II.

Engineering of the E. coli Outer Membrane Protein FhuA to overcome the Hydrophobic Mismatch in Thick Polymeric Membranes

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Fioroni Marco

2011-03-01

Full Text Available Abstract Background Channel proteins like the engineered FhuA Δ1-159 often cannot insert into thick polymeric membranes due to a mismatch between the hydrophobic surface of the protein and the hydrophobic surface of the polymer membrane. To address this problem usually specific block copolymers are synthesized to facilitate protein insertion. Within this study in a reverse approach we match the protein to the polymer instead of matching the polymer to the protein. Results To increase the FhuA Δ1-159 hydrophobic surface by 1 nm, the last 5 amino acids of each of the 22 β-sheets, prior to the more regular periplasmatic β-turns, were doubled leading to an extended FhuA Δ1-159 (FhuA Δ1-159 Ext. The secondary structure prediction and CD spectroscopy indicate the β-barrel folding of FhuA Δ1-159 Ext. The FhuA Δ1-159 Ext insertion and functionality within a nanocontainer polymeric membrane based on the triblock copolymer PIB1000-PEG6000-PIB1000 (PIB = polyisobutylene, PEG = polyethyleneglycol has been proven by kinetic analysis using the HRP-TMB assay (HRP = Horse Radish Peroxidase, TMB = 3,3',5,5'-tetramethylbenzidine. Identical experiments with the unmodified FhuA Δ1-159 report no kinetics and presumably no insertion into the PIB1000-PEG6000-PIB1000 membrane. Furthermore labeling of the Lys-NH2 groups present in the FhuA Δ1-159 Ext channel, leads to controllability of in/out flux of substrates and products from the nanocontainer. Conclusion Using a simple "semi rational" approach the protein's hydrophobic transmembrane region was increased by 1 nm, leading to a predicted lower hydrophobic mismatch between the protein and polymer membrane, minimizing the insertion energy penalty. The strategy of adding amino acids to the FhuA Δ1-159 Ext hydrophobic part can be further expanded to increase the protein's hydrophobicity, promoting the efficient embedding into thicker/more hydrophobic block copolymer membranes.

Engineering of the E. coli outer membrane protein FhuA to overcome the hydrophobic mismatch in thick polymeric membranes.

Science.gov (United States)

Muhammad, Noor; Dworeck, Tamara; Fioroni, Marco; Schwaneberg, Ulrich

2011-03-17

Channel proteins like the engineered FhuA Δ1-159 often cannot insert into thick polymeric membranes due to a mismatch between the hydrophobic surface of the protein and the hydrophobic surface of the polymer membrane. To address this problem usually specific block copolymers are synthesized to facilitate protein insertion. Within this study in a reverse approach we match the protein to the polymer instead of matching the polymer to the protein. To increase the FhuA Δ1-159 hydrophobic surface by 1 nm, the last 5 amino acids of each of the 22 β-sheets, prior to the more regular periplasmatic β-turns, were doubled leading to an extended FhuA Δ1-159 (FhuA Δ1-159 Ext). The secondary structure prediction and CD spectroscopy indicate the β-barrel folding of FhuA Δ1-159 Ext. The FhuA Δ1-159 Ext insertion and functionality within a nanocontainer polymeric membrane based on the triblock copolymer PIB(1000)-PEG(6000)-PIB(1000) (PIB = polyisobutylene, PEG = polyethyleneglycol) has been proven by kinetic analysis using the HRP-TMB assay (HRP = Horse Radish Peroxidase, TMB = 3,3',5,5'-tetramethylbenzidine). Identical experiments with the unmodified FhuA Δ1-159 report no kinetics and presumably no insertion into the PIB(1000)-PEG(6000)-PIB(1000) membrane. Furthermore labeling of the Lys-NH(2) groups present in the FhuA Δ1-159 Ext channel, leads to controllability of in/out flux of substrates and products from the nanocontainer. Using a simple "semi rational" approach the protein's hydrophobic transmembrane region was increased by 1 nm, leading to a predicted lower hydrophobic mismatch between the protein and polymer membrane, minimizing the insertion energy penalty. The strategy of adding amino acids to the FhuA Δ1-159 Ext hydrophobic part can be further expanded to increase the protein's hydrophobicity, promoting the efficient embedding into thicker/more hydrophobic block copolymer membranes.

Temporal Changes in Extracellular Polymeric Substances on Hydrophobic and Hydrophilic Membrane Surfaces in a Submerged Membrane Bioreactor

KAUST Repository

Matar, Gerald Kamil

2016-03-02

Membrane surface hydrophilic modification has always been considered to mitigating biofouling in membrane bioreactors (MBRs). Four hollow-fiber ultrafiltration membranes (pore sizes ∼0.1 μm) differing only in hydrophobic or hydrophilic surface characteristics were operated at a permeate flux of 10 L/m2.h in the same lab-scale MBR fed with synthetic wastewater. In addition, identical membrane modules without permeate production (0 L/m2.h) were operated in the same lab-scale MBR. Membrane modules were autopsied after 1, 10, 20 and 30 days of MBR operation, and total extracellular polymeric substances (EPS) accumulated on the membranes were extracted and characterized in detail using several analytical tools, including conventional colorimetric tests (Lowry and Dubois), liquid chromatography with organic carbon detection (LC-OCD), fluorescence excitation - emission matrices (FEEM), fourier transform infrared (FTIR) and confocal laser scanning microscope (CLSM). The transmembrane pressure (TMP) quickly stabilized with higher values for the hydrophobic membranes than hydrophilic ones. The sulfonated polysulfone (SPSU) membrane had the highest negatively charged membrane surface, accumulated the least amount of foulants and displayed the lowest TMP. The same type of organic foulants developed with time on the four membranes and the composition of biopolymers shifted from protein dominance at early stages of filtration (day 1) towards polysaccharides dominance during later stages of MBR filtration. Nonmetric multidimensional scaling of LC-OCD data showed that biofilm samples clustered according to the sampling event (time) regardless of the membrane surface chemistry (hydrophobic or hydrophilic) or operating mode (with or without permeate flux). These results suggest that EPS composition may not be the dominant parameter for evaluating membrane performance and possibly other parameters such as biofilm thickness, porosity, compactness and structure should be considered

The Comparative Study on Vapor-Polymerization and Pressure-dependent Conductance Behavior in Polypyrrole-hybridized Membranes

Energy Technology Data Exchange (ETDEWEB)

Hanif, Zahid; Lee, Seyeong; Arsalani, Nasir; Geckeler, Kurt E.; Hong, Sukwon; Yoon, Myung-Han [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of)

2016-02-15

In this study, commercially available cellulose membranes were hybridized with conjugated polymer via vapor-phase polymerization using pyrrole and iron chloride as a monomer and oxidant, respectively. The iron (III) chloride layer dip-coated on the hydrophilic cell ulose surface oxidized the vaporized pyrrole monomer leading to the polypyrrole-cellulose hybrid membrane. The conductivity of hybrid membrane was optimized by varying the oxidant concentration and the monomer vapor exposure time. The various surface characterizations of polypyrrole-cellulose hybrid membrane show that the conductive polypyrrole layer was uniformly deposited onto the surface of cellulose fibrous networks unlike the polypyrrole-nylonhybrid membrane prepared in the similar way. The polypyrrole-incorporated cellulose networks exhibits steeper electrical conductance increase over the vertical pressure than its nylon counterpart. Our result suggests that the polypyrrole-cellulose hybrid membrane can be applicable for a disposable high-load pressure sensor.

The Comparative Study on Vapor-Polymerization and Pressure-dependent Conductance Behavior in Polypyrrole-hybridized Membranes

International Nuclear Information System (INIS)

Hanif, Zahid; Lee, Seyeong; Arsalani, Nasir; Geckeler, Kurt E.; Hong, Sukwon; Yoon, Myung-Han

2016-01-01

In this study, commercially available cellulose membranes were hybridized with conjugated polymer via vapor-phase polymerization using pyrrole and iron chloride as a monomer and oxidant, respectively. The iron (III) chloride layer dip-coated on the hydrophilic cell ulose surface oxidized the vaporized pyrrole monomer leading to the polypyrrole-cellulose hybrid membrane. The conductivity of hybrid membrane was optimized by varying the oxidant concentration and the monomer vapor exposure time. The various surface characterizations of polypyrrole-cellulose hybrid membrane show that the conductive polypyrrole layer was uniformly deposited onto the surface of cellulose fibrous networks unlike the polypyrrole-nylonhybrid membrane prepared in the similar way. The polypyrrole-incorporated cellulose networks exhibits steeper electrical conductance increase over the vertical pressure than its nylon counterpart. Our result suggests that the polypyrrole-cellulose hybrid membrane can be applicable for a disposable high-load pressure sensor.

Poly-thiosemicarbazide/gold nanoparticles catalytic membrane: In-situ growth of well-dispersed, uniform and stable gold nanoparticles in a polymeric membrane

KAUST Repository

Villalobos, Luis Francisco

2014-11-01

This work presents a method that achieves the highest loading, published so far, of non-agglomerated and well-distributed gold nanoparticles (AuNPs) inside a polymeric membrane. The method uses poly-thiosemicarbazide (PTSC) as the starting material for fabricating the membranes. This polymer contains one chelate site per monomeric unit, resulting in a high content of adsorption sites. This helps to achieve such high loading without agglomeration, along with the strong interaction of the chelate sites with the metal ions and the fact that they are distributed homogeneously along the membrane structure. The simple and scalable three-step procedure developed in this work resulted in a PTSC membrane containing 33.5 wt.% Au/PTSC in the form of 2.9 nm AuNPs. The membrane demonstrated catalytic activity for the reduction of 4-Nitrophenol (4-NP) to 4-Aminophenol (4-AP). © 2013 Elsevier B.V.

Polymeric synthetic geo membranes in reservoirs waterproofing in the Kingdom of Morocco

International Nuclear Information System (INIS)

Blanco Fernandez, M.

2015-01-01

This essay aims to address some of the aspects related to polymeric synthetic geo membranes that could be used in reservoirs of water located in the Kingdom of Morocco. In this regard, it offers a description of the two basic components geo membranes consist of, that is, resins and additives. It also gives an overview of the key pieces of legislation affecting such an issue. Furthermore, it stresses the paramount importance of implementing monitoring procedures in order to assess the condition of geo membranes over time and, if necessary, to proceed to provide for new waterproofing. Lastly, the characteristics of the process monitoring aforementioned are detailed in terms of tensile strength, elongation, tear resistance, dynamic impact, puncture resistance, low-temperature folding. Shore hardness, stress cracking, oxidation induction times, joint strength shear and peeling test, content and dispersion of carbon black and reflection-optical and scanning-electron microscopy. (Author)

Ultra-selective defect-free interfacially polymerized molecular sieve thin-film composite membranes for H2 purification

KAUST Repository

Ali, Zain

2017-10-10

Purification is a major bottleneck towards generating low-cost commercial hydrogen. In this work, inexpensive high-performance H2 separating membranes were fabricated by modifying the commercially successful interfacial polymerization production method for reverse osmosis membranes. Defect-free thin-film composite membranes were formed demonstrating unprecedented mixed-gas H2/CO2 selectivity of ≈ 50 at 140 °C with H2 permeance of 350 GPU, surpassing the permeance/selectivity upper bound of all known polymer membranes by a wide margin. The combination of exceptional separation performance and low manufacturing cost makes them excellent candidates for cost-effective hydrogen purification from steam cracking and similar processes.

Zwitterionic sulfobetaine-grafted poly(vinylidene fluoride) membrane surface with stably anti-protein-fouling performance via a two-step surface polymerization

Energy Technology Data Exchange (ETDEWEB)

Li Qian; Bi Qiuyan; Zhou Bo [Membrane Technology and Engineering Research Center, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Wang Xiaolin, E-mail: xl-wang@tsinghua.edu.cn [Membrane Technology and Engineering Research Center, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2012-03-01

A zwitterionic polymer, poly(3-(methacryloylamino) propyl-dimethyl-(3-sulfopropyl) ammonium hydroxide) (poly(MPDSAH)) was successfully grafted in high density from the surface of poly(vinylidene fluoride) (PVDF) hollow fiber membrane via a two-step polymerization. Poly(2-hydroxyethyl methacrylate) (poly(HEMA)) chains were firstly grafted from outside surface of PVDF membrane through atom transfer radical polymerization (ATRP) to provide the initiation sites for subsequent cerium (Ce (IV))-induced graft copolymerization of polyMPDSAH in the presence of N,N Prime -ethylene bisacrylamide (EBAA) as a cross-linking agent. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) confirmed that the EBAA could stimulate zwitterionic polymers grafting onto the membrane surface. The dense poly(MPDSAH) layers on the PVDF membrane surface were revealed by the scanning electron microscope (SEM). The mechanical property of PVDF membrane was improved by the zwitterionic surface layers. The gravimetry results indicated the grafting amount increased to 520 {mu}g/cm{sup 2} for a copolymerization time of more than 3 h. Static and dynamic water contact angle measurements showed that the surface hydrophilicity of the PVDF membranes was significantly enhanced. As the grafting amount reached 513 {mu}g cm{sup -2}, the value of contact angle dropped to 22.1 Degree-Sign and the amount of protein adsorption decreased to zero. The cyclic experiments for BSA solution filtration demonstrated that the extent of protein fouling was significantly reduced and most of the fouling was reversible. The grafted polymer layer on the PVDF membrane showed a good stability during the membrane cleaning process. The experimental results concluded a good prospect in obtaining the sulfobetaine-modified PVDF membranes with high mechanical strength, good anti-protein-fouling performance, and long-term stability via the two-step polymerization.

Zwitterionic sulfobetaine-grafted poly(vinylidene fluoride) membrane surface with stably anti-protein-fouling performance via a two-step surface polymerization

International Nuclear Information System (INIS)

Li Qian; Bi Qiuyan; Zhou Bo; Wang Xiaolin

2012-01-01

A zwitterionic polymer, poly(3-(methacryloylamino) propyl-dimethyl-(3-sulfopropyl) ammonium hydroxide) (poly(MPDSAH)) was successfully grafted in high density from the surface of poly(vinylidene fluoride) (PVDF) hollow fiber membrane via a two-step polymerization. Poly(2-hydroxyethyl methacrylate) (poly(HEMA)) chains were firstly grafted from outside surface of PVDF membrane through atom transfer radical polymerization (ATRP) to provide the initiation sites for subsequent cerium (Ce (IV))-induced graft copolymerization of polyMPDSAH in the presence of N,N′-ethylene bisacrylamide (EBAA) as a cross-linking agent. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) confirmed that the EBAA could stimulate zwitterionic polymers grafting onto the membrane surface. The dense poly(MPDSAH) layers on the PVDF membrane surface were revealed by the scanning electron microscope (SEM). The mechanical property of PVDF membrane was improved by the zwitterionic surface layers. The gravimetry results indicated the grafting amount increased to 520 μg/cm 2 for a copolymerization time of more than 3 h. Static and dynamic water contact angle measurements showed that the surface hydrophilicity of the PVDF membranes was significantly enhanced. As the grafting amount reached 513 μg cm -2 , the value of contact angle dropped to 22.1° and the amount of protein adsorption decreased to zero. The cyclic experiments for BSA solution filtration demonstrated that the extent of protein fouling was significantly reduced and most of the fouling was reversible. The grafted polymer layer on the PVDF membrane showed a good stability during the membrane cleaning process. The experimental results concluded a good prospect in obtaining the sulfobetaine-modified PVDF membranes with high mechanical strength, good anti-protein-fouling performance, and long-term stability via the two-step polymerization.

Adsorbent filled membranes for gas separation. Part 1. Improvement of the gas separation properties of polymeric membranes by incorporation of microporous adsorbents

NARCIS (Netherlands)

Duval, J.M.; Duval, J.-M.; Folkers, Albertje; Mulder, M.H.V.; Desgrandchamps, G.; Smolders, C.A.; Smolders, C.A.

1993-01-01

The effect of the introduction of specific adsorbents on the gas separation properties of polymeric membranes has been studied. For this purpose both carbon molecular sieves and zeolites are considered. The results show that zeolites such as silicate-1, 13X and KY improve to a large extent the

Specific chlamydial inclusion membrane proteins associate with active Src family kinases in microdomains that interact with the host microtubule network.

Science.gov (United States)

Mital, Jeffrey; Miller, Natalie J; Fischer, Elizabeth R; Hackstadt, Ted

2010-09-01

Chlamydiae are Gram-negative obligate intracellular bacteria that cause diseases with significant medical and economic impact. Chlamydia trachomatis replicates within a vacuole termed an inclusion, which is extensively modified by the insertion of a number of bacterial effector proteins known as inclusion membrane proteins (Incs). Once modified, the inclusion is trafficked in a dynein-dependent manner to the microtubule-organizing centre (MTOC), where it associates with host centrosomes. Here we describe a novel structure on the inclusion membrane comprised of both host and bacterial proteins. Members of the Src family of kinases are recruited to the chlamydial inclusion in an active form. These kinases display a distinct, localized punctate microdomain-like staining pattern on the inclusion membrane that colocalizes with four chlamydial inclusion membrane proteins (Incs) and is enriched in cholesterol. Biochemical studies show that at least two of these Incs stably interact with one another. Furthermore, host centrosomes associate with these microdomain proteins in C. trachomatis-infected cells and in uninfected cells exogenously expressing one of the chlamydial effectors. Together, the data suggest that a specific structure on the C. trachomatis inclusion membrane may be responsible for the known interactions of chlamydiae with the microtubule network and resultant effects on centrosome stability.

Techno-economical evaluation of membrane based biogas upgrading system: A comparison between polymeric membrane and carbon membrane technology

Directory of Open Access Journals (Sweden)

Shamim Haider

2016-10-01

Full Text Available A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre (CHF membrane and compare with a commercially available polymeric membrane (polyimide through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO2, O2, N2. The CHF membrane was modified through oxidation, chemical vapour deposition (CVD and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres (PORCHFs significantly exceeded CHF performance showing higher CO2 permeance (0.021 m3(STP/m2 h bar and CO2/CH4 selectivity of 246 (5 bar feed vs 50 mbar permeate pressure. The highest performance recorded through experiments (CHF and PORCHF was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS. A 300 Nm3/h mixture of CO2/CH4 containing 30–50% CO2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover 99.5% CH4 with 97.5% purity. Net present value (NPV was calculated for base case and optimal pressure (50 bar for CHF and PORCHF. The results indicated that recycle ratio (recycle/feed ranged from 0.2 to 10, specific energy from 0.15 to 0.8 (kW/Nm3feed and specific membrane area from 45 to 4700 (m2/Nm3feed. The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm3 and a lifetime of 15 years, the techno-economic analysis showed that payback time for

Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells.

Science.gov (United States)

Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

2017-01-01

Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide- co -glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization

Energy Technology Data Exchange (ETDEWEB)

Zhu, Lijing, E-mail: zhulijing@nimte.ac.cn; Song, Haiming; Wang, Jiarong; Xue, Lixin, E-mail: xuelx@nimte.ac.cn

2017-05-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. - Highlights: • PSf membranes were modified by in situ cross-linked polymerization. • The modified PSf membranes showed enhanced hydrophilicity. • The anti-fouling and hemocompatibility of PSf membranes were improved.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization

International Nuclear Information System (INIS)

Zhu, Lijing; Song, Haiming; Wang, Jiarong; Xue, Lixin

2017-01-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. - Highlights: • PSf membranes were modified by in situ cross-linked polymerization. • The modified PSf membranes showed enhanced hydrophilicity. • The anti-fouling and hemocompatibility of PSf membranes were improved.

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

OpenAIRE

Akhmetshina, Alsu A.; Davletbaeva, Ilsiya M.; Grebenschikova, Ekaterina S.; Sazanova, Tatyana S.; Petukhov, Anton N.; Atlaskin, Artem A.; Razov, Evgeny N.; Zaripov, Ilnaz I.; Martins, Carla F.; Neves, Lu?sa A.; Vorotyntsev, Ilya V.

2015-01-01

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested ...

The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors

DEFF Research Database (Denmark)

Tirunehe, Gossay; Norddahl, B.

2016-01-01

Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air–water and air–CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas–liquid mediums. CMC....../s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular...... membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (KLa) by a factor of 1.2–1.9 compared to the flat sheet membrane....

[Computer modeling the dependences of the membrane potential for polymeric membrane separated non-homogeneous electrolyte solutions on concentration Rayleigh number].

Science.gov (United States)

Slezak, Izabella H; Jasik-Slezak, Jolanta; Bilewicz-Wyrozumska, Teresa; Slezak, Andrzej

2006-01-01

On the basis of model equation describing the membrane potential delta psi(s) on concentration Rayleigh number (R(C)), mechanical pressure difference (deltaP), concentration polarization coefficient (zeta s) and ratio concentration of solutions separated by membrane (Ch/Cl), the characteristics delta psi(s) = f(Rc)(delta P, zeta s, Ch/Cl) for steady values of zeta s, R(C) and Ch/Cl in single-membrane system were calculated. In this system neutral and isotropic polymeric membrane oriented in horizontal plane, the non-homogeneous binary electrolytic solutions of various concentrations were separated. Nonhomogeneity of solutions is results from creations of the concentration boundary layers on both sides of the membrane. Calculations were made for the case where on a one side of the membrane aqueous solution of NaCl at steady concentration 10(-3) mol x l(-1) (Cl) was placed and on the other aqueous solutions of NaCl at concentrations from 10(-3) mol x l(-1) to 2 x 10(-2) mol x l(-1) (Ch). Their densities were greater than NaCl solution's at 10(-3) mol x l(-1). It was shown that membrane potential depends on hydrodynamic state of a complex concentration boundary layer-membrane-concentration boundary layer, what is controlled by deltaP, Ch/Cl, Rc and Zeta(s).

Solvent and Thermally Resistant Polymeric Membranes for Different Applications

KAUST Repository

Taghreeed, Jalal

2016-11-01

In this work polymeric materials were developed to be used as a solvent and heat resistance membrane for different applications. In ultrafiltration, poly (ether imide sulfone) membranes were manufactured by combining phase inversion and functionalization reaction between epoxy groups and amine modified polyether oligomers (Jeffamine®). Polysilsesquioxanes or oligo silsesquioxanes containing epoxy functionalities were in-situ grown in the casting solution and made available for further reaction with amines in the coagulation/annealing baths. Water permeances up to 1500 l m-2 h-1 bar-1 were obtained with sharp pore size distribution and a pore diameter peak at 66 nm, confirmed by porosimetry, allowing 99.2 % rejection of γ-globulin. The membranes were stable in 50:50 dimethylformamide/water, 50:50 N-methyl pyrrolidone/water and 100 % tetrahydrofuran. In pervaporation, Novel hydrophobic Hyflon®/Extem® and Hyflon®/PVDF were developed and investigated for ethylene glycol dehydration and n-butanol dehydration respectively. For ethylene glycol different Extem® concentrations were evaluated with regard to both flux and amount of water in the permeate side. Eighteen (18) wt% gave more than 90 wt% water in the permeate. Increasing feed temperature from 25 to 85°C increased the water flux from 31 to 91 g m-2 h-1 when using 5 wt% water in ethylene glycol as feed. The water flux of 40 wt% water:ethylene glycol at 45°C was found to be 350 g m-2 h-1. And for n-butanol dehydration the coating protocols for thin defect-free Hyflon® selective layer on the PVDF support was optimized. Water and n-butanol transport was measured, analyzing the effect of operating conditions. The water flux through the newly developed membranes was higher than 150 g m-2 h-1 with selectivity for water higher than 99 wt%. The membrane application can be extended to other solvents, supporting an effective and simple method for dehydration with hydrophobic membranes. In membrane distillation, PVDF

Polymeric-silica-based sols for membrane modification applications: sol-gel synthesis and characterization with SAXS

NARCIS (Netherlands)

de Lange, Rob; de Lange, R.S.A.; Hekkink, J.H.A.; Hekkink, J.H.A.; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.

1995-01-01

Polymeric SiO2 and binary SiO2/TiO2, SiO2/ZrO2 and SiO2/Al2O3 sols, for ceramic membrane modification applications, have been prepared by acid-catalyzed hydrolysis and condensation of alkoxides in alcohol. The sols were characterized with small angle X-ray scattering, using synchrotron radiation.

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2007-01-01

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S 1 ) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S 2 ) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S 1 ) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10 -8 to 1.0 x 10 -1 M Cd 2+ with limit of detection 5.0 x 10 -8 M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants

Schiff bases as cadmium(II) selective ionophores in polymeric membrane electrodes

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)]. E-mail: vinodfcy@iitr.ernet.in; Singh, A.K. [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India); Gupta, Barkha [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247667 (India)

2007-02-05

The construction and performance characteristics of polymeric membrane electrodes based on two neutral ionophores, N,N'-[bis(pyridin-2-yl)formylidene]butane-1,4-diamine (S{sub 1}) and N-(2-pyridinylmethylene)-1,2-benzenediamine (S{sub 2}) for quantification of cadmium ions, are described. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with the electrode having a membrane composition (w/w) of (S{sub 1}) (2.15%):PVC (32.2%):o-NPOE (64.5%):KTpClPB (1.07%). The proposed electrode exhibits Nernstian response in the concentration range of 7.9 x 10{sup -8} to 1.0 x 10{sup -1} M Cd{sup 2+} with limit of detection 5.0 x 10{sup -8} M, performs satisfactorily over wide pH range (2.0-8.0) with a fast response time (10 s). The sensor has been found to work satisfactorily in partially non-aqueous media up to 30% (v/v) content of methanol, ethanol and acetonitrile and could be used for a period of 2 months. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. The practical utility of the membrane electrode has also been observed in the presence of surfactants.

New RO TFC Membranes by Interfacial Polymerization in n-Dodecane with Various co-Solvents.

Science.gov (United States)

Al-Hobaib, Abdullah Sulaiman; Al-Suhybani, Mohammed Sulaiman; Al-Sheetan, Khalid Mohammed; Mousa, Hasan; Shaik, Mohammed Rafi

2016-04-29

The objective of this research is to prepare and characterize a new and highly efficient polyamide TFC RO membrane by interfacial polymerization in dodecane solvent mixed with co-solvents. Three co-solvents were tested namely; acetone, ethyl acetate, and diethyl ether of concentration of 0.5, 1, 2, 3, and 5 wt %. The modified membranes were characterized by SEM, EDX, AFM and contact angle techniques. The results showed that addition of co-solvent results in a decrease in the roughness, pore size and thickness of the produced membranes. However, as the concentration of the co-solvent increases the pore size of the membranes gets larger. Among the three co-solvents tested, acetone was found to result in membranes with the largest pore size and contact angle followed by diethyl ether then ethyl acetate. Measured contact angle increases as the concentration of the co-solvent increases reaching a constant value except for ethyl acetate where it was found to drop. Investigating flux and salt rejection by the formulated membranes showed that higher flux was attained when acetone was used as a co-solvent followed by diethyl ether then ethyl acetate. However, the highest salt rejection was achieved with diethyl ether.

Polymerization of Phenylacetylene-Based Monodendrons with Alkoxy Peripheral Groups and Oxygen/Nitrogen Permeation Behavior of Their Membranes

Directory of Open Access Journals (Sweden)

Takashi Kaneko

2012-01-01

Full Text Available Monodendron monomers with alkoxy peripheral groups were synthesized, and the focal point of monodendrons, terminal acetylene, was polymerized with rhodium catalyst to yield corresponding polydendrons with a high molecular weight. The polydendrons were soluble in common organic solvents and readily formed membranes. Oxygen permselectivity was improved in the polydendrons with a space-persistent dendritic crowd. It was found that the well-defined dendritic and rod-like structure of the polydendrons was useful for permselective membrane.

Comparison of filtration and treatment performance between polymeric and ceramic membranes in anaerobic membrane bioreactor treatment of domestic wastewater

KAUST Repository

Jeong, Yeongmi

2018-02-28

The feasibility of an anaerobic ceramic membrane bioreactor (AnCMBR) was investigated by comparison with a conventional anaerobic membrane bioreactor (AnMBR). With regard to treatment performance, the AnCMBR achieved higher organic removal rates than the AnMBR because the ceramic membranes retained a high concentration of biomass in the reactor. Despite a high mixed liquor suspended solid (MLSS) concentration, the AnCMBR exhibited lower membrane fouling. To elucidate effects of sludge properties on membrane fouling in the AnCMBR and AnMBR, soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) were analyzed. The SMP and EPS concentrations in the AnCMBR were higher than in the AnMBR. This may be because some suspended solids bio-degraded and likely released protein-like SMPs in the AnCMBR. Hydrophobicity and surface charges were analyzed; the sludge in the AnCMBR was found to be more hydrophobic and less negative than in the AnMBR because protein was abundant in the AnCMBR. Despite the adverse properties of the sludge in the AnCMBR, it showed more stable filtration performance than the AnMBR. This is because the alumina-based ceramic membrane had a superhydrophilic surface and could thus mitigate membrane fouling by hydrophilic-hydrophobic repulsion. The findings from this study have significant implications for extending the application of AnCMBRs to, for example, treatment of high-strength organic waste such as food waste or livestock manure.

Comparison of filtration and treatment performance between polymeric and ceramic membranes in anaerobic membrane bioreactor treatment of domestic wastewater

KAUST Repository

Jeong, Yeongmi; Kim, Youngjin; Jin, Yongxun; Hong, Seungkwan; Park, Chanhyuk

2018-01-01

The feasibility of an anaerobic ceramic membrane bioreactor (AnCMBR) was investigated by comparison with a conventional anaerobic membrane bioreactor (AnMBR). With regard to treatment performance, the AnCMBR achieved higher organic removal rates than the AnMBR because the ceramic membranes retained a high concentration of biomass in the reactor. Despite a high mixed liquor suspended solid (MLSS) concentration, the AnCMBR exhibited lower membrane fouling. To elucidate effects of sludge properties on membrane fouling in the AnCMBR and AnMBR, soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) were analyzed. The SMP and EPS concentrations in the AnCMBR were higher than in the AnMBR. This may be because some suspended solids bio-degraded and likely released protein-like SMPs in the AnCMBR. Hydrophobicity and surface charges were analyzed; the sludge in the AnCMBR was found to be more hydrophobic and less negative than in the AnMBR because protein was abundant in the AnCMBR. Despite the adverse properties of the sludge in the AnCMBR, it showed more stable filtration performance than the AnMBR. This is because the alumina-based ceramic membrane had a superhydrophilic surface and could thus mitigate membrane fouling by hydrophilic-hydrophobic repulsion. The findings from this study have significant implications for extending the application of AnCMBRs to, for example, treatment of high-strength organic waste such as food waste or livestock manure.

Recent advances on polymeric membranes for membrane reactors

KAUST Repository

Buonomenna, M. G.; Choi, Seung Hak

2012-01-01

. The successful use of membranes in membrane reactors is primary the result of two developments concerning: (i) membrane materials and (ii) membrane structures. The selection of a suited material and preparation technique depends on the application the membrane

Tetra(p-tolyl)borate-functionalized solvent polymeric membrane: a facile and sensitive sensing platform for peroxidase and peroxidase mimetics.

Science.gov (United States)

Wang, Xuewei; Qin, Wei

2013-07-22

The determination of peroxidase activities is the basis for enzyme-labeled bioaffinity assays, peroxidase-mimicking DNAzymes- and nanoparticles-based assays, and characterization of the catalytic functions of peroxidase mimetics. Here, a facile, sensitive, and cost-effective solvent polymeric membrane-based peroxidase detection platform is described that utilizes reaction intermediates with different pKa values from those of substrates and final products. Several key but long-debated intermediates in the peroxidative oxidation of o-phenylenediamine (o-PD) have been identified and their charge states have been estimated. By using a solvent polymeric membrane functionalized by an appropriate substituted tetraphenylborate as a receptor, those cationic intermediates could be transferred into the membrane from the aqueous phase to induce a large cationic potential response. Thus, the potentiometric indication of the o-PD oxidation catalyzed by peroxidase or its mimetics can be fulfilled. Horseradish peroxidase has been detected with a detection limit at least two orders of magnitude lower than those obtained by spectrophotometric techniques and traditional membrane-based methods. As an example of peroxidase mimetics, G-quadruplex DNAzymes were probed by the intermediate-sensitive membrane and a label-free thrombin detection protocol was developed based on the catalytic activity of the thrombin-binding G-quadruplex aptamer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Membrane fouling related to microbial community and extracellular polymeric substances at different temperatures.

Science.gov (United States)

Gao, Da-Wen; Wen, Zhi-Dan; Li, Bao; Liang, Hong

2013-09-01

An anoxic-aerobic membrane bioreactor was established to investigate the role of microorganisms and microbial metabolites in membrane fouling at different temperatures. The results showed that the membrane fouling cycle at 303, 293, and 283 K were 30, 29, and 5.5 days, respectively. Polysaccharides dominated the extracellular polymeric substances (EPS) and soluble microbial products (SMP) at 303 and 293 K, instead, proteins was the predominant composition of metabolites at 283 K. The correlation coefficient (r(2)) was calculated to identify the relationship between temperature (T), filtration resistance (R) and compositions of EPS and SMP. In biocake, the EPS polysaccharides (EPSc) was the most correlative factor to temperature (T) and filtration resistance (R); in mixed liquor, the ratio of SMP polysaccharides to proteins (SMPc/p) was the most correlative factor. The microbial community structure and the dominant species was the major reason causing the change of EPS and SMP composition. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of casein on flux and passage of serum proteins during microfiltration using polymeric spiral-wound membranes at 50°C.

Science.gov (United States)

Zulewska, Justyna; Barbano, David M

2013-04-01

Raw milk (approximately 1,800 kg) was separated at 4°C, pasteurized (at 72°C for 16s), and split into 2 batches. One batch (620 kg) was microfiltered (MF) using pilot-scale ceramic uniform transmembrane pressure Membralox membranes (model EP1940GL0.1 μA, 0.1-μm alumina; Pall Corp., East Hills, NY) to produce retentate and permeate. The permeate from the MF uniform transmembrane pressure was casein-free skim milk (CFSM). The CFSM was MF using polymeric spiral-wound (SW) membranes (model FG7838-OS0x-S, 0.3 μm; Parker-Hannifin Corp., Process Advanced Filtration Division, Tell City, IN) at a concentration factor of 3× and temperature of 50°C. Following the processing of CFSM, the second batch of skim milk (1,105 kg) was processed using the same polymeric membranes to determine how casein content in the feed material for MF with polymeric membranes affects the performance of the system. There was little resistance to passage of milk serum proteins (SP) through a 0.3-μm polyvinylidene fluoride (PVDF) SW membrane at 50°C and no detectable increase in hydraulic resistance of the membrane when processing CFSM. Therefore, milk SP contributed little, if any, to fouling of the PVDF membrane. In contrast, when processing skim milk containing a normal concentration of casein, the flux was much lower than when processing CFSM (17.2 vs. 80.2 kg/m(2) per hour, respectively) and the removal of SP from skim milk with a single-pass 3× bleed-and-feed MF system was also much lower than from CFSM (35.2 vs. 59.5% removal, respectively). Thus, when processing skim milk with a PVDF SW membrane, casein was the major protein foulant that increased hydraulic resistance and reduced passage of SP through the membrane. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Preparation of high-capacity, weak anion-exchange membranes by surface-initiated atom transfer radical polymerization of poly(glycidyl methacrylate) and subsequent derivatization with diethylamine

International Nuclear Information System (INIS)

Qian, Xiaolei; Fan, Hua; Wang, Chaozhan; Wei, Yinmao

2013-01-01

Ion-exchange membrane is of importance for the development of membrane chromatography. In this work, a high-capacity anion-exchange membrane was prepared by grafting of glycidyl methacrylate (GMA) onto the surface of regenerated cellulose (RC) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequent derivatization with diethylamine. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize changes in the chemical functionality, surface topography and pore morphology of the modified membranes. The static capacity of the prepared anion-exchange membrane was evaluated with bovine serum albumin (BSA) as a model protein. The results indicated that the anion-exchange membrane which could reach a maximum capacity of 96 mg/mL for static adsorption possesses a higher adsorption capacity, and the adsorption capacity increases with the polymerization time. The effect of pH and salt concentration confirmed that the adsorption of BSA followed ion-exchange mechanism. The established method would have potential application in the preparation of anion-exchange membrane.

Surface modification of poly(vinylidene fluoride) membrane with hydrophilic and anti-fouling performance via a two-step polymerization

Energy Technology Data Exchange (ETDEWEB)

Chen, Gui-E; Sun, Li; Huang, Hui-Hong; Liu, Yan-Jun [Shanghai Institute of Technology, Shanghai (China); Xu, Zhen-Liang; Yang, Hu [East China University of Science and Technology, Shanghai (China)

2015-12-15

The surface modification of poly (vinylidene fluoride) (PVDF) membrane was performed via a two-step polymerization reactions. Poly (acrylic acid) (PAAc) was first grafted onto the membrane surface for the preparation of PVDF-g-PAAc membrane, and then poly (ethylene glycol) 200 (PEG 200) was immobilized on the membrane surface by the esterification reaction for the fabrication of PVDF-g-PEGA membrane. Attenuated total reflectance (ATR) FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and protein adsorption, water flux, water content and dynamic contact angle were conducted to characterize the structures and performance of the resultant PVDF membranes. The experimental results showed that the adsorption of bovine serum albumin (BSA) on the PVDF-g-PEGA membrane decreased about 80% when the grafting ratio reached to 15 wt%, compared with the pristine PVDF membrane. Moreover, the water contact angle of the membrane dropped to 60.5o, while the membrane pore sizes remained little changed.

Novel Tertiary Amino Containing Blinding Composite Membranes via Raft Polymerization and Their Preliminary CO2 Permeation Performance.

Science.gov (United States)

Zhu, Lifang; Zhou, Mali; Yang, Shanshan; Shen, Jiangnan

2015-04-23

Facile synthesis of poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) star polymers on the basis of the prepolymer chains, PDMAEMA as the macro chain transfer agent and divinyl benzene (DVB) as the cross-linking reagent by reversible addition-fragmentation chain transfer (RAFT) polymerization was described. The RAFT polymerizations of DMAEMA at 70 °C using four RAFT agents with different R and Z group were investigated. The RAFT agents used in these polymerizations were dibenzyl trithiocarbonate (DBTTC), s-1-dodecyl-s'-(α,α'-dimethyl-α-acetic acid) trithiocarbonate (MTTCD), s,s'-bis (2-hydroxyethyl-2'-dimethylacrylate) trithiocarbonate (BDATC) and s-(2-cyanoprop-2-yl)-s-dodecyltrithiocarbonate (CPTCD). The results indicated that the structure of the end-group of RAFT agents had significant effects on the ability to control polymerization. Compared with the above-mentioned RAFT agents, CPTCD provides better control over the molecular weight and molecular weight distribution. The polydispersity index (PDI) was determined to be within the scope of 1.26 to 1.36. The yields, molecular weight, and distribution of the star polymers can be tuned by changing the molar ratio of DVB/PDMAEMA-CPTCD. The chemical composition and structure of the linear and star polymers were characterized by GPC, FTIR, 1H NMR, XRD analysis. For the pure Chitosan membrane, a great improvement was observed for both CO₂ permeation rate and ideal selectivity of the blending composite membrane upon increasing the content of SPDMAEMA-8. At a feed gas pressure of 37.5 cmHg and 30 °C, the blinding composite membrane (Cs: SPDMAEMA-8 = 4:4) has a CO₂ permeation rate of 8.54 × 10⁻⁴ cm³ (STP) cm⁻²∙s⁻¹∙cm∙Hg⁻¹ and a N₂ permeation rate of 6.76 × 10⁻⁵ cm³ (STP) cm⁻²∙s⁻¹∙cm∙Hg⁻¹, and an ideal CO₂/N₂ selectivity of 35.2.

Impact of polymeric membrane breakage on drinking water quality and an online detection method of the breakage.

Science.gov (United States)

Wu, Qilong; Zhang, Zhenghua; Cao, Guodong; Zhang, Xihui

2017-10-15

Polymeric membrane has been widely used for the treatment of drinking water in China, and the total treating capacity has reached up to 3.8 million m 3 /d. However, the membrane breakage found in the membrane modules in many water treatment plants resulted in an increase in turbidity and bacterial amount in the membrane permeate. In this study, a membrane module running for 3 years in a full-scale application was examined in terms of the breaking positions and the numbers of the broken fibers. It was found that most of the breaking positions were mainly on the outlet side of the module and that the distance from these points to the outlet was about 1/10-2/10 length of the membrane module. The lab-scale tests showed that the increase of the numbers of the breaking fibers in the membrane module (the breaking fibers were from 1 to 4 of 75 fibers) resulted in the increase in turbidity, particle count and the amount of total bacteria and coliform bacteria. Meanwhile, the water quality after the filtration with broken membrane fibers was similar to the quality of the raw water, which indicated that once the membrane fiber breakage occurred in the membrane module, the quality of drinking water after membrane filtration was significantly affected. Furthermore, the breaking position closer to the outlet side of the membrane module exposed much higher microbiological risk than those in the middle or near the bottom side. A pilot scale test was conducted by using a membrane module with 6600 fibers, and the effect of the membrane breakage (1-4 broken fibers) on water quality was also investigated. The results indicated that periodical backwashing caused drastic fluctuation of turbidity, particle count and the bacterial amount in the permeate water, which might be due to the washing force and self-blocking action inside the hollow fibers. Moreover, there is a good quantitative relationship (R 2 = 0.945) between particle count and the bacterial amount, which indicated that an

Preparation and Applications of Amylose Supramolecules by Means of Phosphorylase-Catalyzed Enzymatic Polymerization

Directory of Open Access Journals (Sweden)

Jun-ichi Kadokawa

2012-01-01

Full Text Available This paper reviews preparation and applications of amylose supramolecules by means of phosphorylase-catalyzed enzymatic polymerization. When the enzymatic polymerization of α-d-glucose 1-phosphate (G-1-P as a monomer was carried out in the presence of poly(tetrahydrofuran (PTHF of a hydrophobic polyether as a guest polymer, the supramolecule, i.e., an amylose-PTHF inclusion complex, was formed in the process of polymerization. Because the representation of propagation in the polymerization is similar to the way that vines of plants grow twining around rods, this polymerization method for the preparation of amylose-polymer inclusion complexes was proposed to be named “vine-twining polymerization”. Various hydrophobic polyethers, polyesters, poly(ester-ether, and polycarbonates were also employed as the guest polymer in the vine-twining polymerization to produce the corresponding inclusion complexes. To obtain the inclusion complex from a strongly hydrophobic guest polymer, the parallel enzymatic polymerization system was developed as an advanced extension of the vine-twining polymerization. In addition, it was found that amylose selectively includes one side of the guest polymer from a mixture of two resemblant guest polymers, as well as a specific range in molecular weights of the guest PTHF. Amylose also exhibited selective inclusion behavior toward stereoisomers of poly(lactides. Moreover, the preparation of hydrogels through the formation of inclusion complexes of amylose in vine-twining polymerization was achieved.

Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores.

Science.gov (United States)

Tyagi, Sonika; Agarwal, Himanshu; Ikram, Saiqa

2010-01-01

It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50+/-1.0 mV per decade of activity and a working concentration range of 7.2 x 10(-8)-1.0 x 10(-1) M. The electrode gave more stable potential readings when used around pH 2.5-6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7-9 months. Excellent selectivity for Hg(2+) ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.

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

Science.gov (United States)

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

2014-01-01

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

Data supporting the validation of a simulation model for multi-component gas separation in polymeric membranes.

Science.gov (United States)

Giordano, Lorena; Roizard, Denis; Bounaceur, Roda; Favre, Eric

2016-12-01

The article describes data concerning the separation performances of polymeric hollow-fiber membranes. The data were obtained using a model for simulating gas separation, described in the research article entitled "Interplay of inlet temperature and humidity on energy penalty for CO 2 post-combustion capture: rigorous analysis and simulation of a single stage gas permeation process" (L. Giordano, D. Roizard, R. Bounaceur, E. Favre, 2016) [1]. The data were used to validate the model by comparison with literature results. Considering a membrane system based on feed compression only, data from the model proposed and that from literature were compared with respect to the molar composition of permeate stream, the membrane area and specific energy requirement, varying the feed pressure and the CO 2 separation degree.

Development of double chain phosphatidylcholine functionalized polymeric monoliths for immobilized artificial membrane chromatography.

Science.gov (United States)

Wang, Qiqin; Peng, Kun; Chen, Weijia; Cao, Zhen; Zhu, Peijie; Zhao, Yumei; Wang, Yuqiang; Zhou, Haibo; Jiang, Zhengjin

2017-01-06

This study described a simple synthetic methodology for preparing biomembrane mimicking monolithic column. The suggested approach not only simplifies the preparation procedure but also improves the stability of double chain phosphatidylcholine (PC) functionalized monolithic column. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and nano-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained on this double chain PC functionalized monolithic column. It is worth noting that the resulting polymeric monolith exhibits great potential as a useful alternative of commercial immobilized artificial membrane (IAM) columns for in vitro predication of drug-membrane interactions. Furthermore, the comparative study of both double chain and single chain PC functionalized monoliths indicates that the presence or absence of glycerol backbone and the number of acyl chains are not decisive for the predictive ability of IAM monoliths on drug-membrane interactions. This novel PC functionalized monolithic column also exhibited good selectivity for a protein mixture and a set of pharmaceutical compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

A vibrating membrane bioreactor (VMBR): Macromolecular transmission-influence of extracellular polymeric substances

DEFF Research Database (Denmark)

Beier, Søren; Jonsson, Gunnar Eigil

2009-01-01

The vibrating membrane bioreactor (VMBR) system facilitates the possibility of conducting a separation of macromolecules (BSA) from larger biological components (yeast cells) with a relatively high and stable macromolecular transmission at sub-critical flux. This is not possible to achieve...... for a static non-vibrating membrane module. A BSA transmission of 74% has been measured in the separation of 4g/L BSA from 8 g/L dry weight yeast cells in suspension at sub-critical flux (20L/(m(2) h)). However, this transmission is lower than the 85% BSA transmission measured for at pure 4g/L BSA solution....... This can be ascribed to the presence of extracellular polymeric substances (EPS) from the yeast cells. The initial fouling rate for constant sub-critical flux filtration of unwashed yeast cells is 3-4 times larger than for washed yeast cells (18(mbar/h)/5(mbar/h)). At sub-critical flux, an EPS transmission...

Electron paramagnetic resonance spin label titration: a novel method to investigate random and site-specific immobilization of enzymes onto polymeric membranes with different properties

International Nuclear Information System (INIS)

Butterfield, D. Allan; Colvin, Joshua; Liu Jiangling; Wang Jianquan; Bachas, Leonidas; Bhattacharrya, Dibakar

2002-01-01

The immobilization of biological molecules onto polymeric membranes to produce biofunctional membranes is used for selective catalysis, separation, analysis, and artificial organs. Normally, random immobilization of enzymes onto polymeric membranes leads to dramatic reduction in activity due to chemical reactions involved in enzyme immobilization, multiple-point binding, etc., and the extent of activity reduction is a function of membrane hydrophilicity (e.g. activity in cellulosic membrane >> polysulfone membrane). We have used molecular biology to effect site-specific immobilization of enzymes in a manner that orients the active site away from the polymeric membrane surface, thus resulting in higher enzyme activity that approaches that in solution and in increased stability of the enzyme relative to the enzyme in solution. A prediction of this site-specific method of enzyme immobilization, which in this study with subtilisin and organophosphorus hydrolase consists of a fusion tag genetically added to these enzymes and subsequent immobilization via the anti-tag antibody and membrane-bound protein A, is that the active site conformation will more closely resemble that of the enzyme in solution than is the case for random immobilization. This hypothesis was confirmed using a new electron paramagnetic resonance (EPR) spin label active site titration method that determines the amount of spin label bound to the active site of the immobilized enzyme. This value nearly perfectly matched the enzyme activity, and the results suggested: (a) a spectroscopic method for measuring activity and thus the extent of active enzyme immobilization in membrane, which may have advantages in cases where optical methods can not be used due to light scattering interference; (b) higher spin label incorporation (and hence activity) in enzymes that had been site-specifically immobilized versus random immobilization; (c) higher spin label incorporation in enzymes immobilized onto hydrophilic

Macrovoid Defect Growth during Evaporative Casting of Polymeric Membranes

Science.gov (United States)

Greenberg, A. R.; Khare, V. P.; Zartman, J.; Krantz, W. B.; Todd, P.

2003-01-01

Macrovoid (MV) formation is a significant problem in evaporatively cast polymeric membranes. MVs are large, elongated or teardrop-shaped pores (10-50 micron) that can impair membrane structural integrity. Although MVs have been extensively studied, there is no general agreement on the mechanisms governing MV growth. Recently, our research group has formulated the solutocapillary convection (SC) hypothesis, which contends that MV growth involves three principal forces: a Marangoni force generated by surface tension gradients within the MV interface, a viscous drag force, and a gravitationally induced body force. Two sets of complementary experiments were conducted to test the SC hypothesis. Ground-based videomicroscopy flow-visualization (VMFV) was utilized to measure the flow velocities at the MV-casting solution interface and deep within the casting solution. The measurements were performed with casting solutions containing 10 wt% cellulose acetate (CA), 30 wt% H2O, 60 wt% acetone, and 200- ppm TiO2 particles for flow visualization, and the surface tension was controlled by surfactant addition. Qualitatively, the experiments indicated that MV growth occurs in three distinct phases: (1) a very rapid initial growth period, (2) a much slower growth phase, and (3) absorption of selected MVs into the expanding demixed region. The presence of tracer particles inside the MVs suggests the presence of a convective flow, which transfers the particles from the bulk solution to the MV interior. Although the VMFV experiments did not establish any surfactant effect on the interfacial velocities, a statistically significant effect on the MV number density was observed. In the second set of experiments, membranes were cast aboard a KC-135 aircraft under 0-g and 2-g conditions. Despite careful attention to the design and fabrication of the membrane casting apparatus (MCA), several problems were encountered, the most significant of which was the contamination of the casting

Synthesis of polyphenylacetylene by radiation-induced polymerization in deoxycholic acid clathrate

International Nuclear Information System (INIS)

Cataldo, Franco; Strazzulla, Giovanni; Iglesias-Groth, Susana

2009-01-01

Phenylacetylene was polymerized as inclusion compound (clathrate) inside deoxycholic acid (DOCA) crystals. The polymerization was initiated by γ radiation and a total dose of 320 kGy was employed. The resulting polyphenylacetylene (PPA) was isolated by dissolution of deoxycholic acid in boiling ethanol. PPA high polymer was accompanied by a series of phenylacetylene oligomers, which were detected by liquid chromatographic analysis (HPLC). PPA was characterized by electronic absorption spectroscopy and by FT-IR spectroscopy in comparison to a reference PPA prepared by a stereospecific catalyst. The microstructure of PPA from inclusion polymerization was highly trans type, similar to that observed on PPA prepared by bulk radiolysis. No optical activity was detected by polarimetry on PPA prepared by inclusion polymerization. The host-guest complex PPA/DOCA was studied by differential thermal analysis (DTA) and by thermogravimetry (TGA). DTA provided evidences of the host-guest complex formation from the shift of the melting point of DOCA while the TGA confirmed the identity - in terms of thermal behaviour - of the PPA from inclusion polymerization with that from stereospecific polymerization

Chlamydia trachomatis inclusion membrane protein CT850 interacts with the dynein light chain DYNLT1 (Tctex1).

Science.gov (United States)

Mital, Jeffrey; Lutter, Erika I; Barger, Alexandra C; Dooley, Cheryl A; Hackstadt, Ted

2015-06-26

Chlamydia trachomatis actively subverts the minus-end directed microtubule motor, dynein, to traffic along microtubule tracks to the Microtubule Organizing Center (MTOC) where it remains within a membrane bound replicative vacuole for the duration of its intracellular development. Unlike most substrates of the dynein motor, disruption of the dynactin cargo-linking complex by over-expression of the p50 dynamitin subunit does not inhibit C. trachomatis transport. A requirement for chlamydial protein synthesis to initiate this process suggests that a chlamydial product supersedes a requirement for p50 dynamitin. A yeast 2-hybrid system was used to screen the chlamydia inclusion membrane protein CT850 against a HeLa cell cDNA library and identified an interaction with the dynein light chain DYNLT1 (Tctex1). This interaction was at least partially dependent upon an (R/K-R/K-X-X-R/K) motif that is characteristic of DYNLT1 binding domains. CT850 expressed ectopically in HeLa cells localized at the MTOC and this localization is similarly dependent upon the predicted DYNLT1 binding domain. Furthermore, DYNLT1 is enriched at focal concentrations of CT850 on the chlamydial inclusion membrane that are known to interact with dynein and microtubules. Depletion of DYNLT1 disrupts the characteristic association of the inclusion membrane with centrosomes. Collectively, the results suggest that CT850 interacts with DYNLT1 to promote appropriate positioning of the inclusion at the MTOC. Published by Elsevier Inc.

Potentiometric sensors using cotton yarns, carbon nanotubes and polymeric membranes.

Science.gov (United States)

Guinovart, Tomàs; Parrilla, Marc; Crespo, Gastón A; Rius, F Xavier; Andrade, Francisco J

2013-09-21

A simple and generalized approach to build electrochemical sensors for wearable devices is presented. Commercial cotton yarns are first turned into electrical conductors through a simple dyeing process using a carbon nanotube ink. These conductive yarns are then partially coated with a suitable polymeric membrane to build ion-selective electrodes. Potentiometric measurements using these yarn-potentiometric sensors are demonstrated. Examples of yarns that can sense pH, K(+) and NH4(+) are presented. In all cases, these sensing yarns show limits of detection and linear ranges that are similar to those obtained with lab-made solid-state ion-selective electrodes. Through the immobilization of these sensors in a band-aid, it is shown that this approach could be easily implemented in a wearable device. Factors affecting the performance of the sensors and future potential applications are discussed.

Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

KAUST Repository

Vidal, Fernando

2016-07-07

The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

KAUST Repository

Vidal, Fernando; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y.-X.

2016-01-01

The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

Single-molecule resolution of protein dynamics on polymeric membrane surfaces: the roles of spatial and population heterogeneity.

Science.gov (United States)

Langdon, Blake B; Mirhossaini, Roya B; Mabry, Joshua N; Sriram, Indira; Lajmi, Ajay; Zhang, Yanxia; Rojas, Orlando J; Schwartz, Daniel K

2015-02-18

Although polymeric membranes are widely used in the purification of protein pharmaceuticals, interactions between biomolecules and membrane surfaces can lead to reduced membrane performance and damage to the product. In this study, single-molecule fluorescence microscopy provided direct observation of bovine serum albumin (BSA) and human monoclonal antibody (IgG) dynamics at the interface between aqueous buffer and polymeric membrane materials including regenerated cellulose and unmodified poly(ether sulfone) (PES) blended with either polyvinylpyrrolidone (PVP), polyvinyl acetate-co-polyvinylpyrrolidone (PVAc-PVP), or polyethylene glycol methacrylate (PEGM) before casting. These polymer surfaces were compared with model surfaces composed of hydrophilic bare fused silica and hydrophobic trimethylsilane-coated fused silica. At extremely dilute protein concentrations (10(-3)-10(-7) mg/mL), protein surface exchange was highly dynamic with protein monomers desorbing from the surface within ∼1 s after adsorption. Protein oligomers (e.g., nonspecific dimers, trimers, or larger aggregates), although less common, remained on the surface for 5 times longer than monomers. Using newly developed super-resolution methods, we could localize adsorption sites with ∼50 nm resolution and quantify the spatial heterogeneity of the various surfaces. On a small anomalous subset of the adsorption sites, proteins adsorbed preferentially and tended to reside for significantly longer times (i.e., on "strong" sites). Proteins resided for shorter times overall on surfaces that were more homogeneous and exhibited fewer strong sites (e.g., PVAc-PVP/PES). We propose that strong surface sites may nucleate protein aggregation, initiated preferentially by protein oligomers, and accelerate ultrafiltration membrane fouling. At high protein concentrations (0.3-1.0 mg/mL), fewer strong adsorption sites were observed, and surface residence times were reduced. This suggests that at high concentrations

Radiation chemistry of polymeric system

International Nuclear Information System (INIS)

Machi, Sueo; Ishigaki, Isao

1978-01-01

Among wide application of radiation in the field of polymer chemistry, practices of polymerization, graft polymerization, bridging, etc. are introduced hereinafter. As for the radiation sources of radiation polymerization, in addition to the 60 Co-γ ray with long permeation distance which has been usually applied, electron beam accelerators with high energy, large current and high reliability have come to be produced, and the liquid phase polymerization by electron beam has attracted attention industrially. Concerning polymerizing reactions, explanations were given to electron beam polymerization under high dose rate, the polymerization in supercooling state or under high pressure, and emulsifying polymerization. As for radiation bridging, radiation is applied for the bridging of hydrogel, acceleration of bridging and improvement of radiation resistance. It is also utilized for reforming membranes by graft polymerization, and synthesis of polymers for medical use. Application of fixed enzymes in the medical field has been investigated by fixing various enzymes by low temperature γ-ray polymerization with glassy monomers such as HEMA. (Kobatake, H.)

Grafting study of polysulfone polymeric membranes by gamma ray irradiation

International Nuclear Information System (INIS)

Furtado Filho, Acacio A.M.; Gomes, Ailton de S.

2011-01-01

Radiation-induced grafting of styrene poli sulfone films were investigated by simultaneous method in solution using gamma-ray from a radio nuclide 60 Co source. The gamma-ray energy of high intensity induced breaking of chemical bonds leading to free radical formation. The radical start a conventional polymerization sequence comparable with that obtained with a chemical catalyst acting as initiator. The effects of grafting conditions such as irradiation total dose, dose rate and addition of cross linking agent, were studied by means of morphology analysis, thermal degradation and crystallinity. After the grafting reaction, the membranes were submitted to an exhaustive extraction with solvent to remove the polystyrene homopolymer formed. The degree of grafting (DOG) was analyzed by percentage of weight increase. As a result, the reaction always follows the same pattern: DOG increases rapidly initially whilst propagation is the main reaction, then more slowly as termination becomes more frequent. (author)

Temperature responsive track membranes

International Nuclear Information System (INIS)

Omichi, H.; Yoshido, M.; Asano, M.; Tamada, H.

1994-01-01

A new track membrane was synthesized by introducing polymeric hydrogel to films. Such a monomer as amino acid group containing acryloyl or methacryloyl was either co-polymerized with diethylene glycol-bis-ally carbonate followed by on beam irradiation and chemical etching, or graft co-polymerized onto a particle track membrane of CR-39. The pore size was controlled in water by changing the water temperature. Some films other than CR-39 were also examined. (author). 11 refs, 7 figs

Polymer Inclusion Membrane Containing a Tripodal Diglycolamide Ligand: Actinide Ion Uptake and Transport Studies

NARCIS (Netherlands)

Mahanty, B.; Mohapatra, P.K.; Raut, D.R.; Das, D.K.; Behere, P.G.; Afzal, M.; Verboom, Willem

2016-01-01

A cellulose triacetate (CTA)-based polymer inclusion membrane (PIM) containing a C-pivot tripodal diglycolamide (T-DGA) as the carrier extractant and 2-nitrophenyl octyl ether (NPOE) as the plasticizer shows potential for the uptake of actinides from acidic feed solutions. The uptake of actinides

Selectively gas-permeable composite membrane and process for production thereof

International Nuclear Information System (INIS)

Okita, K.; Asako, S.

1984-01-01

A selectively gas-permeable composite membrane and a process for producing said composite membrane are described. The composite membrane comprises a polymeric material support and a thin membrane deposited on the support, said thin membrane being obtained by glow discharge plasma polymerization of an organosilane compound containing at least one double bond or triple bond. Alternatively, the composite membrane comprises a polymeric material support having an average pore diameter of at least 0.1 micron, a hardened or cross-linked polyorganosiloxane layer on the support, and a thin membrane on the polyorganosiloxane layer, said thin membrane being obtained by plasma polymerization due to glow discharge of an organosilane compound containing at least one double bond or triple bond

The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors.

Science.gov (United States)

Tirunehe, Gossaye; Norddahl, B

2016-04-01

Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air-water and air-CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas-liquid mediums. CMC solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas-liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (U(G)) range of 0.0004-0.0025 m/s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (K(L)a) by a factor of 1.2-1.9 compared to the flat sheet membrane.

Influence of temperature on radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) nuclear membranes and films

International Nuclear Information System (INIS)

Zhitaryuk, N.I.; Shtan'ko, N.I.

1989-01-01

Temperature effect on kinetics of radiation-induced graft polymerization of styrene onto poly(ethylene terephthalate) (PETP) nuclear membranes with various parameters (pore diameter, the average distance between the pores) as well as onto PETP films with different thickness has been studied. Graft polymerization has been carried out by the methods of preirradiation in air and in vacuum. The overall activation energy of grafting as well as the activation energy of swelling of PETP in toluene has been obtained. It was found that in the method of preirradiation in vacuum the initial grafting rate in Arrhenius plot has two linear ranges. Activation energy in low temperature range correlates with activation energy of PETP swelling. Activation energy in high temperature range is determined by kinetics of graft polymerization in the method of preirradiation in air. Arrhenius plot of the initial grafting rate gives the activation energy that approximately corresponds to the initiation of grafting with oxyradicals. Dependence of PETP matrix critical thickness on temperature has also been obtained. The form of this dependence is identical to the one of the rate of graft polymerization. 33 refs.; 6 figs.; 2 tabs

A novel polyester composite nanofiltration membrane formed by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC)

Science.gov (United States)

Cheng, Jun; Shi, Wenxin; Zhang, Lanhe; Zhang, Ruijun

2017-09-01

A novel polyester thin film composite nanofiltration (NF) membrane was prepared by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC) on polyethersulfone (PES) supporting membrane. The performance of the polyester composite NF membrane was optimized by regulating the preparation parameters, including reaction time, pH of the aqueous phase solution, pentaerythritol concentration and TMC concentration. A series of characterization, including permeation experiments, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential analyzer and chlorine resistance experiments, were employed to study the properties of the optimized membrane. The results showed that the optimized polyester composite NF membrane exhibited very high rejection of Na2SO4 (98.1%), but the water flux is relatively low (6.1 L/m2 h, 0.5 MPa, 25 °C). The order of salt rejections is Na2SO4 > MgSO4 > MgCl2 > NaCl, which indicated the membrane was negatively charged, just consistent with the membrane zeta potential results. After treating by NaClO solutions with different concentrations (100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm) for 48 h, the results demonstrated that the polyester NF membrane had good chlorine resistance. Additionally, the polyester TFC NF membrane exhibits good long-term stability.

New separation technique. Catalytically functionated separation membrane

Energy Technology Data Exchange (ETDEWEB)

Urgami, Tadashi [Kansai Univ., Osaka (Japan)

1989-02-01

This report introduces research examples, showing the fundamental principle of the membrane by separating the catalytically functionated separation membrane into enzyme fixing separation membrane, polymerized metal complex separation membrane and polymer catalyst separation membrane. This membrane can achieve both functions of separation and catalytic reaction simultaneously and has sufficient possibility to combine powerful functions. Enzyme fixing separation membrane is prepared by carrier combination method, bridging method or covering method and the enzyme fixing method with polymerized complex in which enzyme is controlled to prevent the activity lowering as much as possible and enzyme is fixed from an aqueous solution into polymer membrane. This membrane is applied to the continuous manufacturing of invert sugar from cane sugar and adsorption and removing of harmful substances from blood by utilizing both micro-capsuled urease and active carbon. Alginic acid-copper (II) complex membrane is used for the polymerized metal complex membrane and polystyrene sulfonate membrane is used for the polymer catalyst separation membrane. 28 refs., 4 figs., 1 tabs.

Electrode-analytical properties of polyvinylchloride membranes based on triple metal-polymeric complexes

Directory of Open Access Journals (Sweden)

Katerina V. Matorina

2015-10-01

Full Text Available The influence of the nature of the electrode-active substances (EAS, the composition of the external and internal solutions on the formation of the analytical signal of polyvinylchloride (PVC membranes based on associates and triple metal-polymeric complexes (TMPC was established. Dehumidification of synthesized membranes increases with the content of polyvinylpyrrolidone (PVP. The value of the swelling degree is more than two times greater for membranes, which contain as EAS TMPC, relative to membranes based on associates. The value of water absorption of membranes is determined by the nature of EAS. They formed a series of increasing of the swelling degree such as associate < background membrane < TMPC. Swelling of the background membrane is explained by the physical sorption of water molecules on the surface of plasticized membrane. Hydration of PVP macromolecules varies with the introduction of metal ions, macromolecules unit undergoes a conformational transition. PVP macromolecules form tunnels or cavities where complex particles distributed and additional water accumulated through the second coordination layer. Constructed sensors based on TMPC have slope of electrode function equal to 25 mV/pC. Linear dependence of potential on the polymer concentration is observed in the range of 5–7 pC units. Sensors based on associates have slope of the electrode function of 20–25 mV/pC that can be varied depending on the nature of the EAS. Working range is 4–8 pC. Response time of sensor is less than 1 min. The optimal time for conditioning of the synthesized PVC membrane is 24 hours. Potentiometric sensors have been developed for the determination of residual amounts of low molecular PVP which is a food additive E 1201 commonly used for thickening, stabilizing and clarifying of food products. The content of PVP was determined in real objects (apple juice, beer, red wine and cognac with using the polyvinylpyrrolidone sensors (Sr < 0.08. The

Chlamydia trachomatis IncA Is Localized to the Inclusion Membrane and Is Recognized by Antisera from Infected Humans and Primates†

OpenAIRE

Bannantine, John P.; Stamm, Walter E.; Suchland, Robert J.; Rockey, Daniel D.

1998-01-01

Chlamydia psittaci produces a collection of proteins, termed IncA, IncB, and IncC, that are localized to the chlamydial inclusion membrane. In this report we demonstrate that IncA is also produced by Chlamydia trachomatis. C. trachomatis IncA is structurally similar to C. psittaci IncA and is also localized to the inclusion membrane. Immunoblot analysis demonstrated that sera from C. trachomatis-infected patients and from experimentally infected monkeys both recognized C. trachomatis IncA.

Immobilization of β-galactosidase from Kluyveromyces lactis onto polymeric membrane surfaces: effect of surface characteristics.

Science.gov (United States)

Güleç, Hacı Ali

2013-04-01

The aim of this study was to investigate the effects of surface characteristics of plain and plasma modified cellulose acetate (CA) membranes on the immobilization yield of β-galactosidases from Kluyveromyces lactis (KLG) and its galacto-oligosaccharide (GOS) yield, respectively. Low pressure plasma treatments involving oxygen plasma activation, plasma polymerization (PlsP) of ethylenediamine (EDA) and PlsP of 2-mercaptoethanol were used to modify plain CA membrane surfaces. KLG enzyme was immobilized onto plain and oxygen plasma treated membrane surfaces by simple adsorption. Oxygen plasma activation increased the hydrophylicity of CA membrane surfaces and it improved the immobilization yield of the enzyme by 42%. KLG enzyme was also immobilized onto CA membrane surfaces through amino groups created by PlsP of EDA via covalent binding. Plasma action at 60W plasma power and 15 min. exposure time improved the amount of membrane bounded enzyme by 3.5-fold. The enrichment of the amount of amino groups via polyethyleneimine (PEI) addition enhanced this increase from 3.5-fold to 4.5-fold. Although high enzyme loading was achived (65-83%), both of the methods dramatically decreased the enzyme activity (11-12%) and GOS yield due to probably negative effects of active amino groups. KLG enzyme was more effectively immobilized onto thiolated CA membrane surface created by PlsP of 2-mercaptoethanol with high immobilization yield (70%) and especially high enzyme activity (46%). Immobilized enzymes on the CA membranes treated by PlsP were successively reutilized for 5-8 cycles at 25°C and enzymatic derivatives retained approximately 75-80% of their initial activites at the end of the reactions. Copyright © 2012 Elsevier B.V. All rights reserved.

A vibrating membrane bioreactor operated at supra- and sub-critical flux: Influence of extracellular polymeric substances from yeast cells

DEFF Research Database (Denmark)

Beier, Søren Prip; Jonsson, Gunnar Eigil

2007-01-01

A vibrating membrane bioreactor, in which the fouling problems are reduced by vibrating a hollow fiber membrane module, has been tested in constant flux microfiltration above (supra-critical) and below (sub-critical) an experimentally determined critical flux. Suspensions of bakers yeast cells were...... chosen as filtration medium (dry weight 4 g/l). The influence of extracellular polymeric substances (EPS) from the yeast cells is evaluated by UV absorbance measurements of the bulk supernatant during filtration. The critical flux seems to be an interval or a relative value rather than an absolute value....... Filtration just below the critical flux (sub-critical) seems to be a good compromise between acceptable flux level and acceptable increase of fouling resistance and trans-membrane pressure (TMP) in a given time period. EPS from the yeast cells causes the membrane module to foul and part of the fouling...

Comparison of Hexane Vapour Permeation in Two Different Polymeric Membranes via an Innovative In-line FID Detection Method

Directory of Open Access Journals (Sweden)

Z. Petrusová

2017-07-01

Full Text Available This manuscript presents a novel method for the analysis of vapour permeation through polymeric membranes based on in-line analysis of the permeate with an FID detector. The hexane vapour permeation was studied for two commercially available membranes, namely low-density polyethylene (LDPE and thin-film-composite polyamide (PA membrane. The hexane permeation was studied at temperatures of 25–45 °C, hexane vapour activity in the range of 0.2–0.8 and trans-membrane pressures of 5–50 kPa. Two fundamentally different membranes were chosen to demonstrate the potential and sensitivity of the permeation apparatus. Upon increasing the temperature from 25 to 45 °C, the flux in LDPE was found to increase almost fourfold over the whole activity range. The nonlinear increase of the flux with activity indicates plasticization of the polymer by hexane. Contrarily, the flux in the PA membrane increases almost linearly with activity, with only a minor upward curvature. Since the PA is far away from any phase transition, it is less temperature-dependent than LDPE. The activation energy for permeation demonstrates that the temperature dependence in the LDPE membrane is dominated by changes in diffusion, whereas it is dominated by changes in solubility in the PA membrane.

Viscoelastic Properties of Extracellular Polymeric Substances Can Strongly Affect Their Washing Efficiency from Reverse Osmosis Membranes.

Science.gov (United States)

Ferrando Chavez, Diana Lila; Nejidat, Ali; Herzberg, Moshe

2016-09-06

The role of the viscoelastic properties of biofouling layers in their removal from the membrane was studied. Model fouling layers of extracellular polymeric substances (EPS) originated from microbial biofilms of Pseudomonas aeruginosa PAO1 differentially expressing the Psl polysaccharide were used for controlled washing experiments of fouled RO membranes. In parallel, adsorption experiments and viscoelastic modeling of the EPS layers were conducted in a quartz crystal microbalance with dissipation (QCM-D). During the washing stage, as shear rate was elevated, significant differences in permeate flux recovery between the three different EPS layers were observed. According to the amount of organic carbon remained on the membrane after washing, the magnitude of Psl production provides elevated resistance of the EPS layer to shear stress. The highest flux recovery during the washing stage was observed for the EPS with no Psl. Psl was shown to elevate the layer's shear modulus and shear viscosity but had no effect on the EPS adhesion to the polyamide surface. We conclude that EPS retain on the membrane as a result of the layer viscoelastic properties. These results highlight an important relation between washing efficiency of fouling layers from membranes and their viscoelastic properties, in addition to their adhesion properties.

UV-Induced Radical Photo-Polymerization: A Smart Tool for Preparing Polymer Electrolyte Membranes for Energy Storage Devices

Directory of Open Access Journals (Sweden)

Claudio Gerbaldi

2012-06-01

Full Text Available In the present work, the preparation and characterization of quasi-solid polymer electrolyte membranes based on methacrylic monomers and oligomers, with the addition of organic plasticizers and lithium salt, are described. Noticeable improvements in the mechanical properties by reinforcement with natural cellulose hand-sheets or nanoscale microfibrillated cellulose fibers are also demonstrated. The ionic conductivity of the various prepared membranes is very high, with average values approaching 10^-3 S cm^-1 at ambient temperature. The electrochemical stability window is wide (anodic breakdown voltages > 4.5 V vs. Li in all the cases along with good cyclability in lithium cells at ambient temperature. The galvanostatic cycling tests are conducted by constructing laboratory-scale lithium cells using LiFePO₄ as cathode and lithium metal as anode with the selected polymer electrolyte membrane as the electrolyte separator. The results obtained demonstrate that UV induced radical photo-polymerization is a well suited method for an easy and rapid preparation of easy tunable quasi-solid polymer electrolyte membranes for energy storage devices.

UV-Induced Radical Photo-Polymerization: A Smart Tool for Preparing Polymer Electrolyte Membranes for Energy Storage Devices

Directory of Open Access Journals (Sweden)

Claudio Gerbaldi

2012-10-01

Full Text Available In the present work, the preparation and characterization of quasi-solid polymer electrolyte membranes based on methacrylic monomers and oligomers, with the addition of organic plasticizers and lithium salt, are described. Noticeable improvements in the mechanical properties by reinforcement with natural cellulose hand-sheets or nanoscale microfibrillated cellulose fibers are also demonstrated. The ionic conductivity of the various prepared membranes is very high, with average values approaching 10-3 S cm-1 at ambient temperature. The electrochemical stability window is wide (anodic breakdown voltages > 4.5 V vs. Li in all the cases along with good cyclability in lithium cells at ambient temperature. The galvanostatic cycling tests are conducted by constructing laboratory-scale lithium cells using LiFePO4 as cathode and lithium metal as anode with the selected polymer electrolyte membrane as the electrolyte separator. The results obtained demonstrate that UV induced radical photo-polymerization is a well suited method for an easy and rapid preparation of easy tunable quasi-solid polymer electrolyte membranes for energy storage devices.

Development of a hexavalent chromium ISFET sensor with a polymeric membrane including tributylphosphate

International Nuclear Information System (INIS)

Zazoua, A.; Zougar, S.; Kherrat, R.; Samar, M.H.; Jaffrezic-Renault, N.; Errachid, A.; Abbaci, A.

2006-01-01

This paper presents a first report on chromium ISFET (ion-sensitive field effect transistor) based on a polymeric membrane (siloprene) including an ionophore (tributylphosphate) sensitive for hexavalent chromium. The sensor sensitivity as a function of the pH was studied; its value is minimum in a pH interval from 5.5 to 7.5. The sensitivity for hexavalent chromium was found to be 15 mV/loga Cr 6+ in the range of 10 -4 to 10 -2 M. The detection limit was found to be 10 -5 M. The studied interfering ions are Pb(II) and Cd(II) that do not represent a great perturbation upon the response for hexavalent chromium

Development of a hexavalent chromium ISFET sensor with a polymeric membrane including tributylphosphate

Energy Technology Data Exchange (ETDEWEB)

Zazoua, A. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Zougar, S. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Kherrat, R. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Samar, M.H. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria); Jaffrezic-Renault, N. [CEGELY-UMR 5005 CNRS, Ecole centrale de Lyon, 69134 Ecully cedex (France)]. E-mail: Nicole.Jaffrezic@ec-lyon.fr; Errachid, A. [Center of Reference for Bioengineering in Catalonia (CREBEC), Laboratory of Nanobioengineering, Parc Cientific de Barcelona, Universidad de Barcelona C/ Josep Samitier 1-5, 08028 Barcelona (Spain); Abbaci, A. [Universite de Annaba, BP 12, El-Hadjar, Annaba (Algeria)

2006-03-15

This paper presents a first report on chromium ISFET (ion-sensitive field effect transistor) based on a polymeric membrane (siloprene) including an ionophore (tributylphosphate) sensitive for hexavalent chromium. The sensor sensitivity as a function of the pH was studied; its value is minimum in a pH interval from 5.5 to 7.5. The sensitivity for hexavalent chromium was found to be 15 mV/loga {sub Cr{sup 6+}} in the range of 10{sup -4} to 10{sup -2} M. The detection limit was found to be 10{sup -5} M. The studied interfering ions are Pb(II) and Cd(II) that do not represent a great perturbation upon the response for hexavalent chromium.

Influence of membrane properties on fouling in submerged membrane bioreactors

NARCIS (Netherlands)

van der Marel, P.; Zwijnenburg, A.; Kemperman, Antonius J.B.; Wessling, Matthias; Temmink, Hardy; van der Meer, Walterus Gijsbertus Joseph

2010-01-01

Polymeric flat-sheet membranes with different properties were used in filtration experiments with activated sludge from a pilot-scale MBR to investigate the influence of membrane pore size, surface porosity, pore morphology, and hydrophobicity on membrane fouling. An improved flux-step method was

Surface nanostructuring of thin film composite membranes via grafting polymerization and incorporation of ZnO nanoparticles

Science.gov (United States)

Isawi, Heba; El-Sayed, Magdi H.; Feng, Xianshe; Shawky, Hosam; Abdel Mottaleb, Mohamed S.

2016-11-01

A new approach for modification of polyamid thin film composite membrane PA(TFC) using synthesized ZnO nanoparticles (ZnO NPs) was shown to enhance the membrane performances for reverse osmosis water desalination. First, active layer of synthesis PA(TFC) membrane was activated with an aqueous solution of free radical graft polymerization of hydrophilic methacrylic acid (MAA) monomer onto the surface of the PA(TFC) membrane resulting PMAA-g-PA(TFC). Second, the PA(TFC) membrane has been developed by incorporation of ZnO NPs into the MAA grafting solution resulting the ZnO NPs modified PMAA-g-PA(TFC) membrane. The surface properties of the synthesized nanoparticles and prepared membranes were investigated using the FTIR, XRD and SEM. Morphology studies demonstrated that ZnO NPs have been successfully incorporated into the active grafting layer over PA(TFC) composite membranes. The zinc leaching from the ZnO NPs modified PMAA-g-PA(TFC) was minimal, as shown by batch tests that indicated stabilization of the ZnO NPs on the membrane surfaces. Compared with the a pure PA(TFC) and PMAA-g-PA(TFC) membranes, the ZnO NPs modified PMAA-g-PA(TFC) was more hydrophilic, with an improved water contact angle (∼50 ± 3°) over the PMAA-g-PA(TFC) (63 ± 2.5°). The ZnO NPs modified PMAA-g-PA(TFC) membrane showed salt rejection of 97% (of the total groundwater salinity), 99% of dissolved bivalent ions (Ca2+, SO42-and Mg2+), and 98% of mono valent ions constituents (Cl- and Na+). In addition, antifouling performance of the membranes was determined using E. coli as a potential foulant. This demonstrates that the ZnO NPs modified PMAA-g-PA(TFC) membrane can significantly improve the membrane performances and was favorable to enhance the selectivity, permeability, water flux, mechanical properties and the bio-antifouling properties of the membranes for water desalination.

Detecting Levels of Polyquaternium-10 (PQ-10) via Potentiometric Titration with Dextran Sulphate and Monitoring the Equivalence Point with a Polymeric Membrane-Based Polyion Sensor

OpenAIRE

Ferguson, Stephen A.; Wang, Xuewei; Meyerhoff, Mark E.

2016-01-01

Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels. Mixtures containing both PQ-10 and sodium lauryl sulfate (SLS) are used as model sample...

The use of nanoparticles in polymeric and ceramic membrane structures: Review of manufacturing procedures and performance improvement for water treatment

Energy Technology Data Exchange (ETDEWEB)

Kim, Jeonghwan [Department of Environmental Engineering, INHA University, Nam-gu, Yonghyun-dong 253, Incheon 402-751 (Korea, Republic of); Van der Bruggen, Bart, E-mail: bart.vanderbruggen@cit.kuleuven.b [K.U. Leuven, Department of Chemical Engineering, Laboratory for Applied Physical Chemistry and Environmental Technology, W. de Croylaan 46, B-3001 Leuven (Belgium)

2010-07-15

Membrane separations are powerful tools for various applications, including wastewater treatment and the removal of contaminants from drinking water. The performance of membranes is mainly limited by material properties. Recently, successful attempts have been made to add nanoparticles or nanotubes to polymers in membrane synthesis, with particle sizes ranging from 4 nm up to 100 nm. Ceramic membranes have been fabricated with catalytic nanoparticles for synergistic effects on the membrane performance. Breakthrough effects that have been reported in the field of water and wastewater treatment include fouling mitigation, improvement of permeate quality and flux enhancement. Nanomaterials that have been used include titania, alumina, silica, silver and many others. This paper reviews the role of engineered nanomaterials in (pressure driven) membrane technology for water treatment, to be applied in drinking water production and wastewater recycling. Benefits and drawbacks are described, which should be taken into account in further studies on potential risks related to release of nanoparticles into the environment. - Nanoparticles show a great potential for application in polymeric and ceramic membrane structures, in view of fouling mitigation and catalytic breakdown processes.

The use of nanoparticles in polymeric and ceramic membrane structures: Review of manufacturing procedures and performance improvement for water treatment

International Nuclear Information System (INIS)

Kim, Jeonghwan; Van der Bruggen, Bart

2010-01-01

Membrane separations are powerful tools for various applications, including wastewater treatment and the removal of contaminants from drinking water. The performance of membranes is mainly limited by material properties. Recently, successful attempts have been made to add nanoparticles or nanotubes to polymers in membrane synthesis, with particle sizes ranging from 4 nm up to 100 nm. Ceramic membranes have been fabricated with catalytic nanoparticles for synergistic effects on the membrane performance. Breakthrough effects that have been reported in the field of water and wastewater treatment include fouling mitigation, improvement of permeate quality and flux enhancement. Nanomaterials that have been used include titania, alumina, silica, silver and many others. This paper reviews the role of engineered nanomaterials in (pressure driven) membrane technology for water treatment, to be applied in drinking water production and wastewater recycling. Benefits and drawbacks are described, which should be taken into account in further studies on potential risks related to release of nanoparticles into the environment. - Nanoparticles show a great potential for application in polymeric and ceramic membrane structures, in view of fouling mitigation and catalytic breakdown processes.

Polymeric membranes for guided bone regeneration.

Science.gov (United States)

Gentile, Piergiorgio; Chiono, Valeria; Tonda-Turo, Chiara; Ferreira, Ana M; Ciardelli, Gianluca

2011-10-01

In this review, different barrier membranes for guided bone regeneration (GBR) are described as a useful surgical technique to enhance bone regeneration in damaged alveolar sites before performing implants and fitting other dental appliances. The GBR procedure encourages bone regeneration through cellular exclusion and avoids the invasion of epithelial and connective tissues that grow at the defective site instead of bone tissue. The barrier membrane should satisfy various properties, such as biocompatibility, non-immunogenicity, non-toxicity, and a degradation rate that is long enough to permit mechanical support during bone formation. Other characteristics such as tissue integration, nutrient transfer, space maintenance and manageability are also of interest. In this review, various non-resorbable and resorbable commercially available membranes are described, based on expanded polytetrafluoroethylene, poly(lactic acid), poly(glycolic acid) and their copolymers. The polyester-based membranes are biodegradable, permit a single-stage procedure, and have higher manageability than non-resorbable membranes; however, they have shown poor biocompatibility. In contrast, membranes based on natural materials, such as collagen, are biocompatible but are characterized by poor mechanical properties and stability due to their early degradation. Moreover, new approaches are described, such as the use of multi-layered, graft-copolymer-based and composite membranes containing osteoconductive ceramic fillers as alternatives to conventional membranes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of solids retention time on membrane fouling: characterization of extracellular polymeric substances and soluble microbial products.

Science.gov (United States)

Duan, Liang; Tian, Zhiyong; Song, Yonghui; Jiang, Wei; Tian, Yuan; Li, Shan

2015-01-01

The objective of this study was to investigate the influence of solids retention time (SRT) on membrane fouling and the characteristics of biomacromolecules. Four identical laboratory-scale membrane bioreactors (MBRs) were operated with SRTs for 10, 20, 40 and 80 days. The results indicated that membrane fouling occurred faster and more readily under short SRTs. Fouling resistance was the primary source of filtration resistance. The modified fouling index (MFI) results suggested that the more ready fouling at short SRTs could be attributed to higher concentrations of soluble microbial products (SMP). Fourier transform infrared (FTIR) spectra indicated that the SRT had a weak influence on the functional groups of the total extracellular polymeric substances (TEPS) and SMP. However, the MBR under a short SRT had more low-molecular-weight (MW) compounds (100 kDa). Aromatic protein and tryptophan protein-like substances were the dominant groups in the TEPS and SMP, respectively.

The characteristics of extracellular polymeric substances and soluble microbial products in moving bed biofilm reactor-membrane bioreactor.

Science.gov (United States)

Duan, Liang; Jiang, Wei; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W

2013-11-01

The characteristics of extracellular polymeric substances (EPS) and soluble microbial products (SMP) in conventional membrane bioreactor (MBR) and in moving bed biofilm reactor-membrane bioreactors (MBBR-MBR) were investigated in long-term (170 days) experiments. The results showed that all reactors had high removal efficiency of ammonium and COD, despite very different fouling conditions. The MBBR-MBR with media fill ratio of 26.7% had much lower total membrane resistance and no obvious fouling were detected during the whole operation. In contrast, MBR and MBBR-MBR with lower and higher media fill experienced more significant fouling. Low fouling at optimum fill ratio may be due to the higher percentage of small molecular size (100 kDa) of EPS and SMP in the reactor. The composition of EPS and SMP affected fouling due to different O-H bonds in hydroxyl functional groups, and less polysaccharides and lipids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fabrication of green polymeric membranes

KAUST Repository

Kim, Dooli; Nunes, Suzana Pereira

2017-01-01

Provided herein are methods of fabricating membranes using polymers with functionalized groups such as sulfone (e.g., PSf and PES), ether (e.g., PES), acrylonitrile (e.g., PAN), fluoride(e.g., pvdf and other fluoropolymers), and imide (e.g., extem) and ionic liquids. Also provided are membranes made by the provided methods.

Fabrication of green polymeric membranes

KAUST Repository

Kim, Dooli

2017-06-16

Provided herein are methods of fabricating membranes using polymers with functionalized groups such as sulfone (e.g., PSf and PES), ether (e.g., PES), acrylonitrile (e.g., PAN), fluoride(e.g., pvdf and other fluoropolymers), and imide (e.g., extem) and ionic liquids. Also provided are membranes made by the provided methods.

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

Science.gov (United States)

Akhmetshina, Alsu A; Davletbaeva, Ilsiya M; Grebenschikova, Ekaterina S; Sazanova, Tatyana S; Petukhov, Anton N; Atlaskin, Artem A; Razov, Evgeny N; Zaripov, Ilnaz I; Martins, Carla F; Neves, Luísa A; Vorotyntsev, Ilya V

2015-12-30

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf₂N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N₂, NH₃, H₂S, and CO₂ gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF₆] and [emim][Tf₂N]. The modification of SILMs by nanosize silica particles leads to an increase of NH₃ separation relatively to CO₂ or H₂S.

Potentiometric flow injection system for determination of reductants using a polymeric membrane permanganate ion-selective electrode based on current-controlled reagent delivery.

Science.gov (United States)

Song, Wenjing; Ding, Jiawang; Liang, Rongning; Qin, Wei

2011-10-17

A polymeric membrane permanganate-selective electrode has been developed as a current-controlled reagent release system for potentiometric detection of reductants in flow injection analysis. By applying an external current, diffusion of permanganate ions across the polymeric membrane can be controlled precisely. The permanganate ions released at the sample-membrane interface from the inner filling solution of the electrode are consumed by reaction with a reductant in the sample solution thus changing the measured membrane potential, by which the reductant can be sensed potentiometrically. Ascorbate, dopamine and norepinephrine have been employed as the model reductants. Under the optimized conditions, the potential peak heights are proportional to the reductant concentrations in the ranges of 1.0×10(-5) to 2.5×10(-7)M for ascorbate, of 1.0×10(-5) to 5.0×10(-7)M for dopamine, and of 1.0×10(-5) to 5.0×10(-7)M for norepinephrine, respectively with the corresponding detection limits of 7.8×10(-8), 1.0×10(-7) and 1.0×10(-7)M. The proposed system has been successfully applied to the determination of reductants in pharmaceutical preparations and vegetables, and the results agree well with those of iodimetric analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

Use of cold microfiltration retentates produced with polymeric membranes for standardization of milks for manufacture of pizza cheese.

Science.gov (United States)

Govindasamy-Lucey, S; Jaeggi, J J; Johnson, M E; Wang, T; Lucey, J A

2007-10-01

Pizza cheese was manufactured with milk (12.1% total solids, 3.1% casein, 3.1% fat) standardized with microfiltered (MF) and diafiltered retentates. Polymeric, spiral-wound MF membranes were used to process cold (pizza. Nitrogen recoveries were significantly higher in MF standardized cheeses. Fat recoveries were higher in the pH6.3MF cheese than the control or pH6.4MF cheese. Moisture-adjusted cheese yield was significantly higher in the 2 MF-fortified cheeses compared with the control cheese. Maximum loss tangent (LT(max)) values were not significantly different among the 3 cheeses, suggesting that these cheeses had similar meltability. The LT(max) values increased during ripening. The temperature at which the LT(max) was observed was highest in control cheese and was lower in the pH6.3MF cheese than in the pH6.4MF cheese. The temperature of the LT(max) decreased with age for all 3 cheeses. Values of 12% trichloroacetic acid soluble nitrogen levels were similar in all cheeses. Performance on pizza was similar for all cheeses. The use of MF retentates derived with polymeric membranes was successful in increasing cheese yield, and cheese quality was similar in the control and MF standardized cheeses.

New Polymeric Membranes for Organic Solvent Nanofiltration

KAUST Repository

Aburabie, Jamaliah

2017-05-01

The focus of this dissertation was the development, synthesis and modification of polymers for the preparation of membranes for organic solvent nanofiltration. High chemical stability in a wide range of solvents was a key requirement. Membranes prepared from synthesized polymers as well as from commercial polymers were designed and chemically modified to reach OSN requirements. A solvent stable thin-film composite (TFC) membrane is reported, which is fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate. The membranes exhibited high fluxes towards solvents like THF, DMF and DMSO ranging around 20 L/m2 h at 5 bar with a MWCO of around 1000 g/mol. Ultrafiltration PTSC membranes were prepared by non-solvent induced phase separation and crosslinked with GPTMS. The crosslinking reaction was responsible for the formation of an inorganic-type-network that tuned the membrane pore size. The crosslinked membranes acquired high solvent stability in DMSO, DMF and THF with a MWCO above 1300 g/mol. Reaction Induced Phase Separation (RIPS) was introduced as a new method for the preparation of skinned asymmetric membranes. These membranes have two distinctive layers with different morphologies both from the same polymer. The top dense layer is composed of chemically crosslinked polymer chains while the bottom layer is a porous structure formed by non-crosslinked polymer chains. Such membranes were tested for vitamin B12 in solvents after either crosslinking the support or dissolving the support and fixing the freestanding membrane on alumina. Pebax® 1657 was utilized for the preparation of composite membranes by simple coating. Porous PAN membranes were coated with Pebax® 1657 which was then crosslinked using TDI. Crosslinked Pebax® membranes show high stability towards ethanol, propanol and acetone. The membranes were also stable in DMF once crosslinked PAN supports were used. Sodium alginate polymer was investigated for the preparation of thin film composite

Custom-fit polymeric membrane dressing masks in the treatment of second degree facial burns.

Science.gov (United States)

Weissman, Oren; Hundeshagen, Gabriel; Harats, Moti; Farber, Nimrod; Millet, Eran; Winkler, Eyal; Zilinsky, Isaac; Haik, Josef

2013-09-01

Second degree facial burns usually impart high wound site pain levels and patient discomfort due to the abundance of facial sensory innervation, as well as the development of edema and inflammation that accompany wound healing. Frequent changing of adherent dressings causes additional procedural pain and may prolong healing due to recurring damage to the wound bed. We applied face masks, made on-site from a drug free polymeric membrane dressing, to 8 patients with superficial and deep 2nd degree facial burns. Time to full re-epithlialization was recorded during treatment. Pain, overall comfort, and result satisfaction were evaluated using a questionnaire (10-point Likert scales. From 1=minimum to 10=maximum) on follow-up (mean follow up 14.4 months, range 9-18). These results were compared to a historical cohort of patients with facial burns that were treated with an antibiotic ointment. Results showed mean re-epithelialization time of 6.5 days (as compared to 8.5 days in the cohort group), low pain ratings (mean: 2.6; range: 4.7 in the control group), mixed comfort levels (mean: 4.7/10; 4 in the control group) and high result satisfaction (mean: 7.8; 6.2 in the control group). Nursing staff described pain-free dressing changes and positively noted non-adherence and high absorbance capacity of the polymer, necessitating less dressing changes. Inflammation was contained to the actual site of injury. No complications in terms of infection or allergic reaction were observed. Overall, the polymeric membrane facial dressing seems to be a promising means of reducing pain and ensuring uninterrupted wound healing in 2nd degree facial burns. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Carbon Dioxide Separation Using Thermally Optimized Membranes

Science.gov (United States)

Young, J. S.; Jorgensen, B. S.; Espinoza, B. F.; Weimer, M. W.; Jarvinen, G. D.; Greenberg, A.; Khare, V.; Orme, C. J.; Wertsching, A. K.; Peterson, E. S.; Hopkins, S. D.; Acquaviva, J.

2002-05-01

The purpose of this project is to develop polymeric-metallic membranes for carbon dioxide separations that operate under a broad range of industrially relevant conditions not accessible with present membrane units. The last decade has witnessed a dramatic increase in the use of polymer membranes as an effective, economic and flexible tool for many commercial gas separations including air separation, the recovery of hydrogen from nitrogen, carbon monoxide, and methane mixtures, and the removal of carbon dioxide from natural gas. In each of these applications, high fluxes and excellent selectivities have relied on glassy polymer membranes which separate gases based on both size and solubility differences. To date, however, this technology has focused on optimizing materials for near ambient conditions. The development of polymeric materials that achieve the important combination of high selectivity, high permeability, and mechanical stability at temperatures significantly above 25oC and pressures above 10 bar, respectively, has been largely ignored. Consequently, there is a compelling rationale for the exploration of a new realm of polymer membrane separations. Indeed, the development of high temperature polymeric-metallic composite membranes for carbon dioxide separation at temperatures of 100-450 oC and pressures of 10-150 bar would provide a pivotal contribution with both economic and environmental benefits. Progress to date includes the first ever fabrication of a polymeric-metallic membrane that is selective from room temperature to 370oC. This achievement represents the highest demonstrated operating temperature at which a polymeric based membrane has successfully functioned. Additionally, we have generated the first polybenzamidizole silicate molecular composites. Finally, we have developed a technique that has enabled the first-ever simultaneous measurements of gas permeation and membrane compaction at elevated temperatures. This technique provides a unique

Evaluation of a polymer inclusion membrane containing a C-pivot tripodal diglycolamide for Am(III) extraction

International Nuclear Information System (INIS)

Mahanty, B.N.; Das, D.K.; Afzal, Md; Raut, D.R.; Mohapatra, P.K.; Behere, P.G.; Verboom, W.

2014-01-01

The instability of supported liquid membrane (SLM), being used for laboratory scale metal ion separation, can be avoided using Polymer inclusion membranes (PIM). We have been carrying out studies on diglycolamide based extractants including a C-pivot tripodal diglycolamide (T-DGA) for actinide ion separation from acidic feed solution. It was thought of interest to study the properties of T-DGA based PIM containing cellulose triacetate (CTA) as polymer and 2-nitrophenyl octyl ether (NPOE) as the plasticizer for Am(III) uptake and transport

Janus graphene oxide nanosheet: A promising additive for enhancement of polymeric membranes performance prepared via phase inversion.

Science.gov (United States)

Akbari, Mahdi; Shariaty-Niassar, Mojtaba; Matsuura, Takeshi; Ismail, Ahmad Fauzi

2018-10-01

Although polymeric membranes find important role in water and waste water treatment in recent years, their fouling is still an important problem. Application of hydrophilic nanoparticles (NPs) is one of the proposed methods for reducing fouling of membranes but their dispersion and stability in hydrophobic polymer matrix is challenging. In this study Janus functionalization of the NPs was introduced as a promising technique toward achieving this goal. Polysulfone (PSf) membranes containing various concentrations of graphene oxide (GO) nanosheets and Janus graphene oxide (Janus GO) nanosheets (as additives) were fabricated via phase inversion. The synthesized nanosheets were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and dynamic light scattering (DLS). The prepared membranes also were then characterized by scanning electron microscopy (SEM), contact angle (CA), water uptake, porosity, mean pore size and casting solution viscosity. The membrane performance was also tested by determining pure water flux (PWF), bovine serum albumin (BSA) separation, flux reduction by fouling and flux recovery. CA reduced from 85° to 68° and PWF increased from 23.15 L/m 2  h to 230.61 L/m 2  h for PSF and Janus GO nanosheets containing membrane, respectively. Also investigation of antifouling performance of membranes revealed that membrane with the 1 wt.% of Janus GO nanosheets had higher water flux recovery ratio (FRR) and lower irreversible fouling (R ir ) of 84% and 16%, respectively. These improvements were attributed to the better dispersion and stability of Janus GO nanosheets in the prepared mixed matrix membranes. Copyright © 2018 Elsevier Inc. All rights reserved.

Desalination of Sea Water Using Polymer Inclusion Membran (PIM With Aliquat 336-TBP (Tributhyl Phosphate as Carrier Compound

Directory of Open Access Journals (Sweden)

Cholid Djunaidi Muhammad

2018-01-01

Full Text Available Desalination of Sea Water using Polymer Inclusion Membrane has been done. PIM is known has high stability membrane to overcome the instability of liquid membrane. PIM was placed among two phase : source phases was sea water and feed phases was aquadest. Efficiency of desalination is known by determining salinity concentration and ion Na+ in feed phases and stripping phases using refractometer and AAS. while membrane characterization is done using FTIR. SEM and UV-Vis spectroscopy. The PIM membrane that is produced has thin. transparent. clear and flexible properties. The result showed that PIM transport for 24 hours give the highest of salinity transport. there are 92.68% is transported from feed phases and 84.87% in stripping phases. Membrane characterization result by FTIR and UV spectroscopy showed that PIM membrane is stable enough.

Improving Hemocompatibility of Membranes for Extracorporeal Membrane Oxygenators by Grafting Nonthrombogenic Polymer Brushes.

Science.gov (United States)

Obstals, Fabian; Vorobii, Mariia; Riedel, Tomáš; de Los Santos Pereira, Andres; Bruns, Michael; Singh, Smriti; Rodriguez-Emmenegger, Cesar

2018-03-01

Nonthrombogenic modifications of membranes for extracorporeal membrane oxygenators (ECMOs) are of key interest. The absence of hemocompatibility of these membranes and the need of anticoagulation of patients result in severe and potentially life-threatening complications during ECMO treatment. To address the lack of hemocompatibility of the membrane, surface modifications are developed, which act as barriers to protein adsorption on the membrane and, in this way, prevent activation of the coagulation cascade. The modifications are based on nonionic and zwitterionic polymer brushes grafted directly from poly(4-methyl-1-pentene) (TPX) membranes via single electron transfer-living radical polymerization. Notably, this work introduces the first example of well-controlled surface-initiated radical polymerization of zwitterionic brushes. The antifouling layers markedly increase the recalcification time (a proxy of initiation of coagulation) compared to bare TPX membranes. Furthermore, platelet and leukocyte adhesion is drastically decreased, rendering the ECMO membranes hemocompatible. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microscopy analysis of reconstituted COPII coat polymerization and Sec16 dynamics.

Science.gov (United States)

Iwasaki, Hirohiko; Yorimitsu, Tomohiro; Sato, Ken

2017-09-01

The COPII coat and the small GTPase Sar1 mediate protein export from the endoplasmic reticulum (ER) via specialized domains known as the ER exit sites. The peripheral ER protein Sec16 has been proposed to organize ER exit sites. However, it remains unclear how these molecules drive COPII coat polymerization. Here, we characterized the spatiotemporal relationships between the Saccharomyces cerevisiae COPII components during their polymerization by performing fluorescence microscopy of an artificial planar membrane. We demonstrated that Sar1 dissociates from the membrane shortly after the COPII coat recruitment, and Sar1 is then no longer required for the COPII coat to bind to the membrane. Furthermore, we found that Sec16 is incorporated within the COPII-cargo clusters, and that this is dependent on the Sar1 GTPase cycle. These data show how Sar1 drives the polymerization of COPII coat and how Sec16 is spatially distributed during COPII coat polymerization. © 2017. Published by The Company of Biologists Ltd.

Mixed-Matrix Membranes containing an Azine-Linked Covalent Organic Framework: Influence of the polymeric matrix on Post-Combustion CO 2 -capture

KAUST Repository

Shan, Meixia

2017-12-07

The use of an azine-linked covalent organic framework (ACOF-1) as filler in mixed-matrix membranes (MMMs) has been studied for the separation of CO2 from N2. To better understand the mechanisms that govern separation in complex composites, MMMs were prepared with different loadings of ACOF-1 and three different polymers as continuous phase: low flux-mid selectivity Matrimid®, mid flux-high selectivity Polyactive™ and high flux-low selectivity 6FDA:DAM. The homogeneous distribution of ACOF-1 together with the good adhesion between the ACOF-1 particles and the polymer matrices were confirmed by scanning electron microscopy. In mixed-gas CO2/N2 separation a clear influence of the polymer used was observed on the performance of the composite membranes. While for Matrimid® and 6FDA:DAM an overall enhancement of the polymer\\'s separation properties could be achieved, in case of Polyactive™ penetration of the more flexible polymer into the COF porosity resulted in a decreased membrane permeability. The best improvement was obtained for Matrimid®-based MMMs, for which a selectivity increase from 29 to 35, together with an enhancement in permeability from 9.5 to 17.7 Barrer for 16wt% COF loading, was observed. Our results demonstrate that the combination of the filler-polymeric matrix pair chosen is crucial. For a given filler the polymer performance improvement strongly depends on the polymeric matrix selected, where a good match between the discontinuous and continuous phase, both in the terms of compatibility and gas separation properties, is necessary to optimize membrane performance.

Amodiaquine polymeric membrane electrode.

Science.gov (United States)

Malongo, T Kimbeni; Blankert, B; Kambu, O; Amighi, K; Nsangu, J; Kauffmann, J-M

2006-04-11

The construction and electrochemical response characteristics of two types of poly(vinyl chloride) (PVC) membrane sensors for the determination of amodiaquine hydrochloride (ADQ.2HCl) are described. The sensing membrane comprised an ion-pair formed between the cationic drug and sodium tetraphenyl borate (NaTPB) or potassium tetrakis(4-chlorophenyl) borate (KTCPB) in a plasticized PVC matrix. Eight PVC membrane ion-selective electrodes were fabricated and studied. Several plasticizers were studied namely, dioctyl phthalate (DOP), 2-nitrophenyl octyl ether (NPOE), dioctyl phenylphosphonate (DOPP) and bis(2-ethylhexyl)adipate (EHA). The sensors display a fast, stable and near-Nernstian response over a relative wide ADQ concentration range (3.2 x 10(-6) to 2.0 x 10(-2) M), with slopes comprised between 28.5 and 31.4 mV dec(-1) in a pH range comprised between pH 3.7 and 5.5. The assay of amodiaquine hydrochloride in pharmaceutical dosage forms using one of the proposed sensors gave average recoveries of 104.3 and 99.9 with R.S.D. of 0.3 and 0.6% for tablets (Malaritab) and a reconstituted powder containing ADQ.2HCl, respectively. The sensor was also used for dissolution profile studies of two drug formulations. The sensor proved to have a good selectivity for ADQ.2HCl over some inorganic and organic compounds, however, berberine chloride interfered significantly. The results were validated by comparison with a spectrophotometric assay according to the USP pharmacopoeia.

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

Science.gov (United States)

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

2014-05-06

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

Reporter-free potentiometric sensing of boronic acids and their reactions by using quaternary ammonium salt-functionalized polymeric liquid membranes.

Science.gov (United States)

Wang, Xuewei; Yue, Dengfeng; Lv, Enguang; Wu, Lei; Qin, Wei

2014-02-18

The tremendous applications of boronic acids (BAs) in chemical sensing, medical chemistry, molecular assembly, and organic synthesis lead to an urgent demand for developing effective sensing methods for BAs. This paper reports a facile and sensitive potentiometric sensor scheme for heterogeneous detection of BAs based on their unexpected potential responses on quaternary ammonium salt-doped polymeric liquid membranes. (11)B NMR data reveal that a quaternary ammonium chloride can trigger the hydrolysis of an electrically neutral BA in an aprotic solvent. Using the quaternary ammonium salt as the receptor, the BA molecules can be extracted from the sample solution into the polymeric membrane phase and undergo the concomitant hydrolysis. Such salt-triggered hydrolysis generates H(+) ions, which can be coejected into the aqueous phase with the counterions (e.g., Cl(-)) owing to their high hydrophilicities. The perturbation on the ionic partition at the sample-membrane interface changes the phase boundary potential and thus enables the potentiometric sensing of BAs. In contrast to other transduction methods for BAs, for which labeled or separate reporters are exclusively required, the present heterogeneous sensing scheme allows the direct detection of BAs without using any reporter molecules. This technique shows superior detection limits for BAs (e.g., 1.0 × 10(-6) M for phenylboronic acid) as compared to previously reported methods based on colorimetry, fluorimetry, and mass spectrometry. The proposed sensing strategy has also been successfully applied to potentiometric indication of the BA reactions with hydrogen peroxide and saccharides, which allows indirect and sensitive detection of these important species.

Influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb(II) ion-selective electrode

DEFF Research Database (Denmark)

Joon, Narender Kumar; He, Ning; Wagner, Michal

2017-01-01

In this work, the influence of phosphate buffer and proteins on the potentiometric response of a polymeric membrane-based solid-contact Pb2+-selective electrode (Pb2+-ISE) was studied. The effects of bovine serum albumin (BSA) adsorption at the surface of the ion-selective membrane combined...... ions studied (Cu2+, Cd2+). Conditioning of the Pb2+-ISE in 0.01 mol dm–3 PBS resulted in a super-Nernstian response which was related to fixation/extraction of Pb2+ in the ion-selective membrane via precipitation of Pb3(PO4)2 by PO43– anions present in PBS. By conditioning of the Pb2+-ISE in 0.01 mol...

A NEW APPROACH TO THE STUDY OF MUCOADHESIVENESS OF POLYMERIC MEMBRANES USING SILICONE DISCS.

Science.gov (United States)

Nowak, Karolina Maria; Szterk, Arkadiusz; Fiedor, Piotr; Bodek, Kazimiera Henryka

2016-01-01

The introduction of new test methods and the modification of existing ones are crucial for obtaining reliable results, which contributes to the development of innovative materials that may have clinical applications. Today, silicone is commonly used in medicine and the diversity of its applications are continually growing. The aim of this study is to evaluate the mucoadhesiveness of polymeric membranes by a method that modifies the existing test methods through the introduction of silicone discs. The matrices were designed for clinical application in the management of diseases within the oral cavity. The use of silicone discs allows reliable and reproducible results to be obtained, which allows us to make various tensometric measurements. In this study, different types of polymeric matrices were examined, as well as their crosslinking and the presence for the active pharmaceutical ingredient were compared to the pure dosage form. The lidocaine hydrochloride (Lid(HCl)) was used as a model active substance, due to its use in dentistry and clinical safety. The results were characterized by a high repeatability (RSD < 10.6%). The advantage of silicone material due to its mechanical strength, chemical and physical resistance, allowed a new test method using a texture analyzer to be proposed.

Polyethersulfone/clay membranes and its water permeability

International Nuclear Information System (INIS)

Cavalho, Thamyres Cardoso de; Medeiros, Vanessa da Nobrega; Araujo, Edcleide Maria de; Lira, Helio Lucena; Leite, Amanda Melissa Damiao

2017-01-01

Membranes can be considered polymeric or inorganic films that function as a semipermeable barrier to filtration on a molecular scale, separating two phases and restricting, totally or partially, the transportation of one or more chemical species (solute) present in the solution. Therefore, the aim of this work is to produce polyethersulfone membranes (PES) and polyethersulfone/clay by phase inversion technique and evaluate the presence of clay in obtaining membranes for wastewater treatment. The used solvent was dimethylformamide (DMF) and clays were Brasgel PA (MMT) and Cloisite Na (CL Na) in the proportion of 3 to 5% (wt.). By Xray diffraction (XRD), the membranes with 3% of MMT and CL Na clays apparently had partially exfoliated structures. For the composition with 5% of CL Na a small peak was observed, which indicates that this is possibly an intercalated structure or microcomposite. By scanning electron microscopy (SEM), visualizes that the pure surface of the pure PES membrane a structure apparently without pores was observed in the used magnification and without roughness surface when compared to membranes with clay. The measurements of contact angle indicated that the inclusion of clay altered the wetting ability of the membranes. The flow with distilled water for all membranes started high and over time reached a stabilization level. Thus, it can be concluded that the presence and the content of clay altered the morphology of the membrane, contributing to an increase in water flow. (author)

Novel, one-step synthesis of zwitterionic polymer nanoparticles via distillation-precipitation polymerization and its application for dye removal membrane.

Science.gov (United States)

Ibrahim, G P Syed; Isloor, Arun M; Inamuddin; Asiri, Abdullah M; Ismail, Norafiqah; Ismail, Ahmed Fauzi; Ashraf, Ghulam Md

2017-11-21

In this work, poly(MBAAm-co-SBMA) zwitterionic polymer nanoparticles were synthesized in one-step via distillation-precipitation polymerization (DPP) and were characterized. [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) as monomer and N, N'-methylene bis(acrylamide) (MBAAm) as cross-linker are used for the synthesis of nanoparticles. As  far as our knowledge, this is the first such report on the synthesis of poly(MBAAm-co-SBMA) nanoparticles via DPP. The newly synthesized nanoparticles were further employed for the surface modification of polysulfone (PSF) hollow fiber membranes for dye removal. The modified hollow fiber membrane exhibited the improved permeability (56 L/ m 2 h bar) and dye removal (>98% of Reactive Black 5 and >80.7% of Reactive orange 16) with the high permeation of salts. Therefore, the as-prepared membrane can have potential application in textile and industrial wastewater treatment.

An in situ polymerization approach for the synthesis of superhydrophobic and superoleophilic nanofibrous membranes for oil-water separation.

Science.gov (United States)

Shang, Yanwei; Si, Yang; Raza, Aikifa; Yang, Liping; Mao, Xue; Ding, Bin; Yu, Jianyong

2012-12-21

Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO(2) NPs). By employing the F-PBZ/SiO(2) NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161° and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N(2) adsorption method has confirmed the major contribution of SiO(2) NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification.

Highly permeable polymeric membranes based on the incorporation of the functional water channel protein Aquaporin Z

Science.gov (United States)

Kumar, Manish; Grzelakowski, Mariusz; Zilles, Julie; Clark, Mark; Meier, Wolfgang

2007-01-01

The permeability and solute transport characteristics of amphiphilic triblock-polymer vesicles containing the bacterial water-channel protein Aquaporin Z (AqpZ) were investigated. The vesicles were made of a block copolymer with symmetric poly-(2-methyloxazoline)-poly-(dimethylsiloxane)-poly-(2-methyloxazoline) (PMOXA15-PDMS110-PMOXA15) repeat units. Light-scattering measurements on pure polymer vesicles subject to an outwardly directed salt gradient in a stopped-flow apparatus indicated that the polymer vesicles were highly impermeable. However, a large enhancement in water productivity (permeability per unit driving force) of up to ≈800 times that of pure polymer was observed when AqpZ was incorporated. The activation energy (Ea) of water transport for the protein-polymer vesicles (3.4 kcal/mol) corresponded to that reported for water-channel-mediated water transport in lipid membranes. The solute reflection coefficients of glucose, glycerol, salt, and urea were also calculated, and indicated that these solutes are completely rejected. The productivity of AqpZ-incorporated polymer membranes was at least an order of magnitude larger than values for existing salt-rejecting polymeric membranes. The approach followed here may lead to more productive and sustainable water treatment membranes, whereas the variable levels of permeability obtained with different concentrations of AqpZ may provide a key property for drug delivery applications. PMID:18077364

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

Directory of Open Access Journals (Sweden)

Alsu A. Akhmetshina

2015-12-01

Full Text Available Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6] and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([emim][Tf2N] immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S.

Asymmetric polymeric membranes containing a metal-rich dense layer with a controlled thickness and method of making same

KAUST Repository

Peinemann, Klaus-Viktor; Villalobos, Vazquez De La Parra Luis Francisco

2016-01-01

A structure, and methods of making the structure are provided in which the structure can include: a membrane having a first layer and a second layer, the first layer comprising polymer chains formed with coordination complexes with metal ions, and the second layer consisting of a porous support layer formed of polymer chains substantially, if not completely, lacking the presence of metal ions. The structure can be an asymmetric polymeric membrane containing a metal-rich layer as the first layer. In various embodiments the first layer can be a metal-rich dense layer. The first layer can include pores. The polymer chains of the first layer can be closely packed. The second layer can include a plurality of macro voids and can have an absence of the metal ions of the first layer.

Asymmetric polymeric membranes containing a metal-rich dense layer with a controlled thickness and method of making same

KAUST Repository

Peinemann, Klaus-Viktor

2016-01-21

A structure, and methods of making the structure are provided in which the structure can include: a membrane having a first layer and a second layer, the first layer comprising polymer chains formed with coordination complexes with metal ions, and the second layer consisting of a porous support layer formed of polymer chains substantially, if not completely, lacking the presence of metal ions. The structure can be an asymmetric polymeric membrane containing a metal-rich layer as the first layer. In various embodiments the first layer can be a metal-rich dense layer. The first layer can include pores. The polymer chains of the first layer can be closely packed. The second layer can include a plurality of macro voids and can have an absence of the metal ions of the first layer.

Polymeric and Lipid Membranes-From Spheres to Flat Membranes and vice versa.

Science.gov (United States)

Saveleva, Mariia S; Lengert, Ekaterina V; Gorin, Dmitry A; Parakhonskiy, Bogdan V; Skirtach, Andre G

2017-08-15

Membranes are important components in a number of systems, where separation and control of the flow of molecules is desirable. Controllable membranes represent an even more coveted and desirable entity and their development is considered to be the next step of development. Typically, membranes are considered on flat surfaces, but spherical capsules possess a perfect "infinite" or fully suspended membranes. Similarities and transitions between spherical and flat membranes are discussed, while applications of membranes are also emphasized.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization.

Science.gov (United States)

Zhu, Lijing; Song, Haiming; Wang, Jiarong; Xue, Lixin

2017-05-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuronal Differentiation Modulated by Polymeric Membrane Properties.

Science.gov (United States)

Morelli, Sabrina; Piscioneri, Antonella; Drioli, Enrico; De Bartolo, Loredana

2017-01-01

In this study, different collagen-blend membranes were successfully constructed by blending collagen with chitosan (CHT) or poly(lactic-co-glycolic acid) (PLGA) to enhance their properties and thus create new biofunctional materials with great potential use for neuronal tissue engineering and regeneration. Collagen blending strongly affected membrane properties in the following ways: (i) it improved the surface hydrophilicity of both pure CHT and PLGA membranes, (ii) it reduced the stiffness of CHT membranes, but (iii) it did not modify the good mechanical properties of PLGA membranes. Then, we investigated the effect of the different collagen concentrations on the neuronal behavior of the membranes developed. Morphological observations, immunocytochemistry, and morphometric measures demonstrated that the membranes developed, especially CHT/Col30, PLGA, and PLGA/Col1, provided suitable microenvironments for neuronal growth owing to their enhanced properties. The most consistent neuronal differentiation was obtained in neurons cultured on PLGA-based membranes, where a well-developed neuronal network was achieved due to their improved mechanical properties. Our findings suggest that tensile strength and elongation at break are key material parameters that have potential influence on both axonal elongation and neuronal structure and organization, which are of fundamental importance for the maintenance of efficient neuronal growth. Hence, our study has provided new insights regarding the effects of membrane mechanical properties on neuronal behavior, and thus it may help to design and improve novel instructive biomaterials for neuronal tissue engineering. © 2017 S. Karger AG, Basel.

Micro-chip initiator realized by integrating Al/CuO multilayer nanothermite on polymeric membrane

International Nuclear Information System (INIS)

Taton, G; Lagrange, D; Conedera, V; Rossi, C; Renaud, L

2013-01-01

We have developed a new nanothermite based polymeric electro-thermal initiator for non-contact ignition of a propellant. A reactive Al/CuO multilayer nanothermite resides on a 100 µm thick SU-8/PET (polyethyleneterephtalate) membrane to insulate the reactive layer from the silicon bulk substrate. When current is supplied to the initiator, the chemical reaction Al+CuO occurs and sparkles are spread to a distance of several millimeters. A micro-manufacturing process for fabricating the initiator is presented and the electrical behaviors of the ignition elements are also investigated. The characteristics of the initiator made on a 100 µm thick SU-8/PET membrane were compared to two bulk electro-thermal initiators: one on a silicon and one on a Pyrex substrate. The PET devices give 100% of Al/CuO ignition success for an electrical current >250 mA. Glass based reactive initiators give 100% of Al/CuO ignition success for an electrical current >500 mA. Reactive initiators directly on silicon cannot initiate even with a 4 A current. At low currents (<1 A), the initiation time is two orders of magnitude longer for Pyrex initiator compared to those obtained for PET initiator technology. We also observed that, the Al/CuO thermite film on PET membrane reacts within 1 ms (sparkles duration) whereas it reacts within 4 ms on Pyrex. The thermite reaction is 40 times greater in intensity using the PET substrate in comparison to Pyrex. (paper)

Pervaporation separation of ethanol-water mixtures using polyethylenimine composite membranes

Science.gov (United States)

Neidlinger, H.H.; Schissel, P.O.; Orth, R.A.

1985-06-19

Synthetic, organic, polymeric membranes were prepared from polyethylenimine for use with pervaporation apparatus in the separation of ethanol-water mixtures. The polymeric material was prepared in dilute aqueous solution and coated onto a polysulfone support film, from which excess polymeric material was subsequently removed. Cross-links were then generated by limited exposure to toluene-2,4-diisocyanate solution, after which the prepared membrane was heat-cured. The resulting membrane structures showed high selectivity in permeating ethanol or water over a wide range of feed concentrations. 2 tabs.

Study on the thin film composite poly(piperazine-amide) nanofiltration membranes made of different polymeric substrates: Effect of operating conditions

Energy Technology Data Exchange (ETDEWEB)

Misdan, Nurasyikin; Lau, Woei Jye; Ong, Chi Siang; Ismail, Ahmad Fauzi; Matsuura, Takeshi [Universiti Teknologi Malaysia, Skudai (Malaysia)

2015-04-15

Three composite nanofiltration (NF) membranes made of different substrate materials--polysulfone (PSf), polyethersulfone (PES) and polyetherimide (PEI)--were successfully prepared by interfacial polymerization technique. Prior to filtration tests, the composite NF membranes were characterized using field emission scanning electron microscope (FESEM), atomic force microscope (AFM) and X-ray photoelectron spectroscope (XPS). It was observed that the surface properties of composite NF membranes were obviously altered with the use of different substrate materials. The separation performance of the prepared composite NF membranes was further evaluated by varying operating conditions, which included feed salt concentration and operating temperature. Experimental results showed that the water flux of all TFC membranes tended to decrease with increasing Na{sub 2}SO{sub 4} concentration in feed solution, due to the increase in feed osmotic pressure. Of the three TFC membranes studied, PSf-based membrane demonstrated the highest salt rejection but lowest water flux owing to its highest degree of polyamide cross-linking as shown in XPS data. With respect to thermal stability, PEI-based TFC membrane outperformed the rest, overcoming the trade-off effect between permeability and rejection when the feed solution temperature was gradually increased from 30 .deg. C to 80 .deg. C. In addition, the relatively smoother surface of hydrophilic PEI-based membrane when compared with PSf-based membrane was found to be less susceptible to BSA foulants, leading to lower flux decline. This is because smoother surface of polyamide layer would have minimum 'valley clogging,' which improves membrane anti-fouling resistance.

Combination of Bioactive Polymeric Membranes and Stem Cells for Periodontal Regeneration: In Vitro and In Vivo Analyses.

Science.gov (United States)

Gonçalves, Flávia; de Moraes, Míriam Santos; Ferreira, Lorraine Braga; Carreira, Ana Cláudia Oliveira; Kossugue, Patrícia Mayumi; Boaro, Letícia Cristina Cidreira; Bentini, Ricardo; Garcia, Célia Regina da Silva; Sogayar, Mari Cleide; Arana-Chavez, Victor Elias; Catalani, Luiz Henrique

2016-01-01

Regeneration of periodontal tissues requires a concerted effort to obtain consistent and predictable results in vivo. The aim of the present study was to test a new family of bioactive polymeric membranes in combination with stem cell therapy for periodontal regeneration. In particular, the novel polyester poly(isosorbide succinate-co-L-lactide) (PisPLLA) was compared with poly(L-lactide) (PLLA). Both polymers were combined with collagen (COL), hydroxyapatite (HA) and the growth factor bone morphogenetic protein-7 (BMP7), and their osteoinductive capacity was evaluated via in vitro and in vivo experiments. Membranes composed of PLLA/COL/HA or PisPLLA/COL/HA were able to promote periodontal regeneration and new bone formation in fenestration defects in rat jaws. According to quantitative real-time polymerase chain reaction (qRT-PCR) and Alizarin Red assays, better osteoconductive capacity and increased extracellular mineralization were observed for PLLA/COL/HA, whereas better osteoinductive properties were associated with PisPLLA/COL/HA. We concluded that membranes composed of either PisPLLA/COL/HA or PLLA/COL/HA present promising results in vitro as well as in vivo and that these materials could be potentially applied in periodontal regeneration.

Biocompatibility of polypropylene non-woven fabric membrane via UV-induced graft polymerization of 2-acrylamido-2-methylpropane sulfonic acid

Energy Technology Data Exchange (ETDEWEB)

Song Lingjie [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao Jie; Yang Huawei; Jin Jing; Li Xiaomeng [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Stagnaro, Paola [Istituto per Io Studio delle Macromolecole, Consiglio Nazionale delle Ricerche, Via de Marini 6, 16149 Genova (Italy); Yin Jinghua, E-mail: yinjh@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

2011-10-15

This work described the graft polymerization of a sulfonic acid terminated monomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS), onto the surface of polypropylene non-woven (NWF PP) membrane by O{sub 2} plasma pretreatment and UV-induced photografting method. The chemical structure and composition of the modified surfaces were analyzed by FTIR-ATR and XPS, respectively. The wettability was investigated by water contact angle and equilibrium water adsorption. And the biocompatibility of the modified NWF PP membranes was evaluated by protein adsorption and platelet adhesion. It was found that the graft density increased with prolonging UV irradiation time and increasing AMPS concentration; the water contact angles of the membranes decreased from 124{sup o} to 26{sup o} with the increasing grafting density of poly(AMPS) from 0 to 884.2 {mu}g cm{sup -2}, while the equilibrium water adsorption raised from 5 wt% to 75 wt%; the protein absorption was effectively suppressed with the introduction of poly(AMPS) even at the low grafting density (132.4 {mu}g cm{sup -2}); the number of platelets adhering to the modified membrane was dramatically reduced when compared with that on its virgin surface. These results indicated that surface modification of NWF PP membrane with AMPS was a facile approach to construct biocompatible surface.

Self-assembled Block Copolymer Membrane

KAUST Repository

Peinemann, Klaus-Viktor

2012-12-20

Embodiments of the invention include methods for the production of porous membranes. In certain aspects the methods are directed to producing polymeric porous membranes having a narrow pore size distribution.

Self-assembled Block Copolymer Membrane

KAUST Repository

Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

2012-01-01

Embodiments of the invention include methods for the production of porous membranes. In certain aspects the methods are directed to producing polymeric porous membranes having a narrow pore size distribution.

Measure of pore size in micro filtration polymeric membrane using ultrasonic technique and artificial neural networks

International Nuclear Information System (INIS)

Lucas, Carla de Souza

2009-01-01

This work presents a study of the pore size in micro filtration polymeric membranes, used in the nuclear area for the filtration of radioactive liquid effluent, in the residual water treatment of the petrochemical industry, in the electronic industry for the ultrapure water production for the manufacture of conductors and laundering of microcircuits and in many other processes of separation. Diverse processes for measures of pores sizes in membranes exist, amongst these, electronic microscopy, of bubble point and mercury intrusion porosimetry, however the majority of these uses destructive techniques, of high cost or great time of analysis. The proposal of this work is to measure so great of pore being used ultrasonic technique in the time domain of the frequency and artificial neural networks. A receiving/generator of ultrasonic pulses, a immersion transducer of 25 MHz was used, a tank of immersion and microporous membranes of pores sizes of 0,2 μm, 0,4 μm, 0,6 μm, 8 μm, 10 μm and 12 μm. The ultrasonic signals after to cover the membrane, come back to the transducer (emitting/receiving) bringing information of the interaction of the signal with the membranes. These signals had been used for the training of neural networks, and these had supplied the necessary precision the distinction of the same ones. Soon after, technique with the one of electronic microscopy of sweepings was made the comparison of this. The experiment showed very resulted next to the results gotten with the MEV, what it indicated that the studied technique is ideal for measure of pore size in membranes for being not destructive and of this form to be able to be used also on-line of production. (author)

Solutocapillary Convection Effects on Polymeric Membrane Morphology

Science.gov (United States)

Krantz, William B.; Todd, Paul W.; Kinagurthu, Sanjay

1996-01-01

Macro voids are undesirable large pores in membranes used for purification. They form when membranes are cast as thin films on a smooth surface by evaporating solvent (acetone) from a polymer solution. There are two un-tested hypotheses explaining the growth of macro voids. One states that diffusion of the non-solvent (water) is solely responsible, while the other states that solutocapillary convection is the primary cause of macro void growth. Solutocapillary convection is flow-caused by a concentration induced surface-tension gradient. Macrovoid growth in the former hypothesis is gravity independent, while in the latter it is opposed by gravity. To distinguish between these two hypotheses, experiments were designed to cast membranes in zero-gravity. A semi-automated apparatus was designed and built for casting membranes during the 20 secs of zero-g time available in parabolic aircraft flight such as NASA's KC-135. The phase changes were monitored optically, and membrane morphology was evaluated by scanning electron microscopy (SEM). These studies appear to be the first quantitative studies of membrane casting in micro-gravity which incorporate real-time data acquisition. Morphological studies of membranes cast at 0, 1, and 1.8 g revealed the presence of numerous, sparse and no macrovoids respectively. These results are consistent with the predictions of the solutocapillary hypothesis of macrovoid growth.

[Evaluation of the Peusner's coefficients matrix for polymeric membrane and ternary non-electrolyte solutions].

Science.gov (United States)

Jasik-Slęzak, Jolanta; Slęzak-Prochazka, Izabella; Slęzak, Andrzej

2014-01-01

A system of network forms of Kedem-Katchalsky (K-K) equations for ternary non-electrolyte solutions is made of eight matrix equations containing Peusner's coefficients R(ij), L(ij), H(ij), W(ij), K(ij), N(ij), S(ij) or P(ij) (i, j ∈ {1, 2, 3}). The equations are the result of symmetric or hybrid transformation of the classic form of K-K equations by the use of methods of Peusner's network thermodynamics (PNT). Calculating concentration dependences of the determinant of Peusner's coefficients matrixes R(ij), L(ij), H(ij), W(ij), S(ij), N(ij), K(ij) and P(ij) (i, j ∈ {1, 2, 3}). The material used in the experiment was a hemodialysis Nephrophan membrane with specified transport properties (L(p), σ, Ω) in aqueous glucose and ethanol solution. The method involved equations for determinants of the matrixes coefficients R(ij), L(ij), H(ij), W(ij), S(ij), N(ij), K(ij) or P(ij) (i, j ∈ {1, 2, 3}). The objective of calculations were dependences of determinants of Peusner's coeffcients matrixes R(ij), L(ij), H(ij), W(ij), S(ij), N(ij), K(ij) or P(ij) (i, j ∈ {1, 2, 3}) within the conditions of solution homogeneity upon an average concentration of one component of solution in the membrane (C1) with a determined value of the second component (C2). The method of calculating the determinants of Peusner's coeffcients matrixes R(ij), L(ij), H(ij), W(ij), S(ij), N(ij), K(ij) or P(ij) (i, j ∈ {1, 2, 3}) is a new tool that may be applicable in studies on membrane transport. Calculations showed that the coefficients are sensitive to concentration and composition of solutions separated by a polymeric membrane.

Membrane-based ethylene/ethane separation: The upper bound and beyond

KAUST Repository

Rungta, Meha

2013-08-02

Ethylene/ethane separation via cryogenic distillation is extremely energy-intensive, and membrane separation may provide an attractive alternative. In this paper, ethylene/ethane separation performance using polymeric membranes is summarized, and an experimental ethylene/ethane polymeric upper bound based on literature data is presented. A theoretical prediction of the ethylene/ethane upper bound is also presented, and shows good agreement with the experimental upper bound. Further, two ways to overcome the ethylene/ethane upper bound, based on increasing the sorption or diffusion selectivity, is also discussed, and a review on advanced membrane types such as facilitated transport membranes, zeolite and metal organic framework based membranes, and carbon molecular sieve membranes is presented. Of these, carbon membranes have shown the potential to surpass the polymeric ethylene/ethane upper bound performance. Furthermore, a convenient, potentially scalable method for tailoring the performance of carbon membranes for ethylene/ethane separation based on tuning the pyrolysis conditions has also been demonstrated. © 2013 American Institute of Chemical Engineers.

UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

Science.gov (United States)

Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Taltenov, Abzal A.

2015-12-01

In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

Exploring the structure-properties relationships of novel polyamide thin film composite membranes

DEFF Research Database (Denmark)

Briceño, Kelly; Javakhishvili, Irakli; Guo, Haofei

Polysulfone (PSU) is a material widely used in the fabrication of membranes for ultrafiltration and as a support for nanofiltration and reverse osmosis membranes. Interfacial polymerization usually combines amine and acid chloride monomers for the fabrication of thin film composite membranes[1......] . However, only few publications describe it’s usage for the modification of supports for the fabrication of ultrafiltration membranes [2]. This research focuses on the modification of PSU supports to produce new ultrafiltration membranes. The advantages of interfacial polymerization in the fabrication...... of UF membranes includes: Negatively charged PSF surfaces that could be less prone to biofouling Scale up process for the modification of PSU. An alternative to costly and technically challenging processes as in situ interfacial polymerization [3]....

Fluoropolymer materials and architectures prepared by controlled radical polymerizations

DEFF Research Database (Denmark)

Hansen, Natanya Majbritt Louie; Jankova Atanasova, Katja; Hvilsted, Søren

2007-01-01

This review initially summarizes the mechanisms, merits and limitations of the three controlled radical polymerizations: nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP) or metal catalyzed living radical polymerization, and reversible addition–fragmentation chain...... transfer (RAFT) polymerization. This is followed by two parts, one dealing with homo- and copolymerizations of fluorinated methacrylates and acrylates, and a second where fluorinated styrenes, alone or in combination with other monomers, are the main issues. In these parts, initiators (including...... properties and functionalities that can be obtained from these novel fluorinated materials and architectures are especially emphasized. Thus, various amphiphilic, biocompatible or low energy materials, fluorinated nanoparticles and nanoporous films/membranes as well as materials for submicron and nanolevel...

Semipermeable thin-film membranes comprising siloxane, alkoxysilyl and aryloxysilyl oligomers and copolymers

Science.gov (United States)

Babcock, Walter C.; Friesen, Dwayne T.

1988-01-01

Novel semiperimeable membranes and thin film composite (TFC) gas separation membranes useful in the separation of oxygen, nitrogen, hydrogen, water vapor, methane, carbon dioxide, hydrogen sulfide, lower hydrocarbons, and other gases are disclosed. The novel semipermeable membranes comprise the polycondensation reaction product of two complementary polyfunctional compounds, each having at least two functional groups that are mutually reactive in a condensation polymerization reaction, and at least one of which is selected from siloxanes, alkoxsilyls and aryloxysilyls. The TFC membrane comprises a microporous polymeric support, the surface of which has the novel semipermeable film formed thereon, preferably by interfacial polymerization.

Ceramic and polymeric devices for breast brachytherapy - Mammographic and CT response

International Nuclear Information System (INIS)

Nogueira, Luciana B.; Campos, Tarcisio P.R.

2009-01-01

The present research investigates the radiological visibility of ceramic and polymeric devices implanted in breast phantom (in vitro) for future applications in brachytherapy treatments. The main research goal is to investigate the viability of monitoring ceramic and polymeric devices, in vitro based on simple methods of radiological diagnostic, maintaining the easiest access to the population, represented by the conventional X-ray and mammography. The methodology involves the processing of ceramic devices constituted by bioglasses of Sm, SmBa, Ho, HoBa and the production of polymeric devices, such as polymeric membranes incorporating Ho e HoBa. Contrast agent of Barium was introduced in the syntheses of those devices to improve the radiological visibility in breast equivalent-tissue (TE) phantom. The breast phantom is constituted of glandular, adipose and skin TE, reproducing a 5 cm compressed real breast. In the compressed breast phantom, all types of ceramic and polymeric devices were implanted side by side. Radiological images were generated through X-ray equipment, mammography and computerized tomography (TC), for the samples implanted in the compressed breast phantom. The results show that SmBa and HoBa seeds on breast phantom presented suitable radiological visibility, on all the radiological diagnostic methods. However, the X-rays radiological visibility of Sm seeds without contrast was discreet. On mammography and TC images, it was not possible to identify those seeds, because the same ones were degraded after two months immersed in the glandular TE, after placed on the phantom. The Ho seeds were identified on all radiological diagnostic images, although non contrast agent in its constitution was added. However, the holmium polymeric membranes in direct contact with TE did not show Xray radiological visibility. However, the polymeric membranes of HoBa in the same conditions presented efficient X-rays radiological response. For mammography and TC methods

Membrane-based technologies for biogas separations.

Science.gov (United States)

Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

2010-02-01

Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

CO2 capture by polymeric membranes composed of hyper-branched polymers with dense poly(oxyethylene comb and poly(amidoamine

Directory of Open Access Journals (Sweden)

Taniguchi Ikuo

2017-11-01

Full Text Available Due to CO2-philic nature of polyoxyethylene (POE, a dense POE comb structure was tethered onto PMMA backbone to develop CO2 separation membranes over N2. The resulting hyper-branched polymers displayed preferential CO2 permeation. When the polymer thin layer was formed on a high gas permeable polydimethylsiloxane (PDMS support by a spray-coating manner, the resulting thin film composite (TFC membranes displayed very high CO2 permeability. However, the CO2 selectivity, which was the permeability ratio of CO2 over N2, was moderate and lower than 50. To enhance the selectivity, poly(amidoamine (PAMAM was introduced to the hyper-branched polymers in the CO2-selective layer of the TFC membranes. The CO2 selectivity increased from 47 to 90 with increasing PAMAM content to 40 wt%, and it was drastically enhanced to 350 with PAMAM content of 50 wt%. Differential scanning calorimetry (DSC and laser microscope revealed formation of PAMAM-rich domain at the higher amine content, where CO2 could readily migrate in comparison to the other polymeric fractions.

CO2 capture by polymeric membranes composed of hyper-branched polymers with dense poly(oxyethylene) comb and poly(amidoamine)

Science.gov (United States)

Taniguchi, Ikuo; Wada, Norihisa; Kinugasa, Kae; Higa, Mitsuru

2017-11-01

Due to CO2-philic nature of polyoxyethylene (POE), a dense POE comb structure was tethered onto PMMA backbone to develop CO2 separation membranes over N2. The resulting hyper-branched polymers displayed preferential CO2 permeation. When the polymer thin layer was formed on a high gas permeable polydimethylsiloxane (PDMS) support by a spray-coating manner, the resulting thin film composite (TFC) membranes displayed very high CO2 permeability. However, the CO2 selectivity, which was the permeability ratio of CO2 over N2, was moderate and lower than 50. To enhance the selectivity, poly(amidoamine) (PAMAM) was introduced to the hyper-branched polymers in the CO2-selective layer of the TFC membranes. The CO2 selectivity increased from 47 to 90 with increasing PAMAM content to 40 wt%, and it was drastically enhanced to 350 with PAMAM content of 50 wt%. Differential scanning calorimetry (DSC) and laser microscope revealed formation of PAMAM-rich domain at the higher amine content, where CO2 could readily migrate in comparison to the other polymeric fractions.

Conductor polymeric membranes with potential for application in PEM type fuel cells; Membranas polimericas condutoras com potencialidades para aplicacao em celulas a combustivel do tipo PEM

Energy Technology Data Exchange (ETDEWEB)

Brioude, Michel de Meireles; Sodre, Livia Farias; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)

2006-07-01

In this work two series of membranes were prepared; they were based on hybrid organic-inorganic or composite materials and presented potentiality for application in Proton Exchange Membrane Fuel Cell, PEMFC. The polymeric phase was constituted of poly(dimethylsiloxane), PDMS, crosslinked with tetra ethoxysilane, TEOS, with a 70%/30% ratio. Phosphotungstic acid (PWA) or the sodium monododecylsulphate (MDS), as proton conductors, were added to the inorganic network, close to the gel point; the mixtures were transferred to a cast. The films were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The membranes showed good properties, as flexibility, thermal and mechanical stability with potentiality to be used as conducting membranes in technological applications. (author)

The effect of protein-protein and protein-membrane interactions on membrane fouling in ultrafiltration

NARCIS (Netherlands)

Huisman, I.H.; Prádanos, P.; Hernández, A.

2000-01-01

It was studied how protein-protein and protein-membrane interactions influence the filtration performance during the ultrafiltration of protein solutions over polymeric membranes. This was done by measuring flux, streaming potential, and protein transmission during filtration of bovine serum albumin

Controlled release of ethylene via polymeric films for food packaging

Science.gov (United States)

Pisano, Roberto; Bazzano, Marco; Capozzi, Luigi Carlo; Ferri, Ada; Sangermano, Marco

2015-12-01

In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes.

Science.gov (United States)

Gugliuzza, Annarosa; Perrotta, Maria Luisa; Drioli, Enrico

2016-05-16

This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes

Directory of Open Access Journals (Sweden)

Annarosa Gugliuzza

2016-05-01

Full Text Available This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

Synthesis of polymeric micro- and nanostructural materials for application in non-linear optics

International Nuclear Information System (INIS)

Kravets, Lyubov; Palistrant, Natalia; Bivol, Valerii; Robu, Stepan; Barba, Nikolai; Orelovitch, Oleg

2007-01-01

The present paper describes a new approach developed for the preparation of micro- and nanostructural materials on the basis of polymeric compositions used as a matrix in non-linear optics. This approach consists in filling the pores of poly(ethylene terephthalate) track membranes (PET TM) from polymeric compositions using an impregnation method. It is shown that depending on the concentration of polymeric compositions in the solution it is possible to form a variety of micro- and nanostructural materials (tubules and wires as well as composite membranes) with a wide spectrum of characteristics. The developed method of producing micro- and nanostructural materials provides a possible way for creating polymeric objects with non-linear optic properties which can be used to design electronic micro- and nanodevices and to obtain chemical and optical sensors

Incorporation of Graphene-Related Carbon Nanosheets in Membrane Fabrication for Water Treatment: A Review

Directory of Open Access Journals (Sweden)

Jenny Lawler

2016-12-01

Full Text Available The minimization of the trade-off between the flux and the selectivity of membranes is a key area that researchers are continually working to optimise, particularly in the area of fabrication of novel membranes. Flux versus selectivity issues apply in many industrial applications of membranes, for example the unwanted diffusion of methanol in fuel cells, retention of valuable proteins in downstream processing of biopharmaceuticals, rejection of organic matter and micro-organisms in water treatment, or salt permeation in desalination. The incorporation of nanosheets within membrane structures can potentially lead to enhancements in such properties as the antifouling ability, hydrophilicy and permeability of membranes, with concomitant improvements in the flux/selectivity balance. Graphene nanosheets and derivatives such as graphene oxide and reduced graphene oxide have been investigated for this purpose, for example inclusion of nanosheets within the active layer of Reverse Osmosis or Nanofiltration membranes or the blending of nanosheets as fillers within Ultrafiltration membranes. This review summarizes the incorporation of graphene derivatives into polymeric membranes for water treatment with a focus on a number of industrial applications, including desalination and pharmaceutical removal, where enhancement of productivity and reduction in fouling characteristics have been afforded by appropriate incorporation of graphene derived nanosheets during membrane fabrication.

Technology of ceramic and polymeric membranes for oil/water separation; Tecnologia de membranas ceramicas e polimericas para separacao oleo/agua

Energy Technology Data Exchange (ETDEWEB)

Silva, A.A; Souto, K.M; Silva, Adriano A.; Lira, H.L.; Carvalho, L.H.; Costa, A.C.F.M. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

2004-07-01

In last years, separation techniques by membranes and membranes grew of a laboratory simple tool for an industrial process with a considerable technical and commercial impact. Today, membranes have been being widely used in the treatment of the oily/water, because they offer chemical, thermal resistance and resistance the pressure for a wide variety of alimentation terms. Membrane can be defined as a barrier that separates two phases and that restricts, total or partially, the transportation of one or several present chemical species in the phases. The morphology of the membrane and nature of the material that constitutes are some characteristics that are going to define application kind. The ideal structure for these filters is the asymmetric, formed by one or more layers of different pores size, with gradual reduction of the pores size, when approaches the side filtrate. Having in mind that the environmental legislations more process with membranes offers a new option to face these challenges. The membranes typically used in the oil and water separation act as a barrier for the emulsified oil and solubilization. In the petroleum production and refined oil water mixed with oil is prosecuted in great volumes in lots of processes, this mixture should be treated to separate the oil of water before it can return to the environment or even to be reused in the process. This review aims relate studies done with ceramic and polymeric membranes using a separation oil/water system mounted in laboratory scale in UFCG/CCT/ANP/PHH25. The results show that filtration membranes, micro filtration and ultrafiltration were very effective in oil/water separation. (author)

Development of a new class of flexible polymeric membranes for sensing, nanofiltration & cascaded separation

Science.gov (United States)

Du, Nian

The last decade has witnessed an explosion of interests in the science and technology of engineered nanomaterials. While the benefits of nanotechnology are widely publicized, the discussion about the transformation of nanomaterials in the environment, and their potential impacts on human health has just begun. Nanoscale particles, whether ultrafine, nano, engineered, intentional, or incidental, pose significant health effects. New approaches for environmental monitoring of nanomaterials at high sensitivity and in real-time are particularly needed. Since nanoparticles must be isolated from complex environmental and biological matrices, the most effective and simple method of isolating engineered nanomaterials from air or water is filtration. Hence the overall project objective of this work is to develop innovative methods that can simultaneously remove, detect and inactivate diverse nanostructured materials. At the center of the technology is a novel class of polymeric filters capable of simultaneously removing and detecting metal and metal oxide nanoparticles. This project reports the development of a new class of self-standing, flexible, phase-inverted, poly(amic) acid membranes with experimentally-controlled nanopores ranging from less than 10nm to greater than 100nm. Compared to most commercial filter membranes, phase-inverted PAA membranes were found to exhibit superior durability and higher efficiency. The filtration efficiency was ˜99.97% for a number of nanoparticles including Quantum Dots, TiO2, Au and Ag. This work also showed that PAA membranes could be used to separate mixtures of nanoparticles. Although the separation does not show much selectivity according to the NPs’ chemical composition, it shows the ability to separate efficiently based on nanoparticle size. PAA showed an excellent performance not only for nanoparticle isolation at sub-nanometer size ranges, but also as a platform for the detection of engineered nanoparticles at low ppb levels

Electrochemical Impedance Spectroscopy—A Simple Method for the Characterization of Polymer Inclusion Membranes Containing Aliquat 336

Science.gov (United States)

O'Rourke, Michelle; Duffy, Noel; De Marco, Roland; Potter, Ian

2011-01-01

Electrochemical impedance spectroscopy (EIS) has been used to estimate the non-frequency dependent (static) dielectric constants of base polymers such as poly(vinyl chloride) (PVC), cellulose triacetate (CTA) and polystyrene (PS). Polymer inclusion membranes (PIMs) containing different amounts of PVC or CTA, along with the room temperature ionic liquid Aliquat 336 and plasticizers such as trisbutoxyethyl phosphate (TBEP), dioctyl sebecate (DOS) and 2-nitrophenyloctyl ether (NPOE) have been investigated. In this study, the complex and abstract method of EIS has been applied in a simple and easy to use way, so as to make the method accessible to membrane scientists and engineers who may not possess the detailed knowledge of electrochemistry and interfacial science needed for a rigorous interpretation of EIS results. The EIS data reported herein are internally consistent with a percolation threshold in the dielectric constant at high concentrations of Aliquat 336, which illustrates the suitability of the EIS technique since membrane percolation with ion exchangers is a well-known phenomenon. PMID:24957616

Use of a Ceramic Membrane to Improve the Performance of Two-Separate-Phase Biocatalytic Membrane Reactor

OpenAIRE

Ranieri, G; Mazzei, R; Wu, Z; Li, K; Giorno, L

2016-01-01

Biocatalytic membrane reactors (BMR) combining reaction and separation within the same unit have many advantages over conventional reactor designs. Ceramic membranes are an attractive alternative to polymeric membranes in membrane biotechnology due to their high chemical, thermal and mechanical resistance. Another important use is their potential application in a biphasic membrane system, where support solvent resistance is highly needed. In this work, the preparation of asymmetric ceramic ho...

Evaluation of the damage of cell wall and cell membrane for various extracellular polymeric substance extractions of activated sludge.

Science.gov (United States)

Guo, Xuesong; Liu, Junxin; Xiao, Benyi

2014-10-20

Extracellular polymeric substances (EPS) are susceptible to contamination by intracellular substances released during the extraction of EPS owing to the damage caused to microbial cell structures. The damage to cell walls and cell membranes in nine EPS extraction processes of activated sludge was evaluated in this study. The extraction of EPS (including proteins, carbohydrates and DNA) was the highest using the NaOH extraction method and the lowest using formaldehyde extraction. All nine EPS extraction methods in this study resulted in cell wall and membrane damage. The damage to cell walls, evaluated by 2-keto-3-deoxyoctonate (KDO) and N-acetylglucosamine content changes in extracted EPS, was the most significant in the NaOH extraction process. Formaldehyde extraction showed a similar extent of damage to cell walls to those detected in the control method (centrifugation), while those in the formaldehyde-NaOH and cation exchange resin extractions were slightly higher than those detected in the control. N-acetylglucosamine was more suitable than KDO for the evaluation of cell wall damage in the EPS extraction of activated sludge. The damage to cell membranes was characterized by two fluorochromes (propidium iodide and FITC Annexin V) with flow cytometry (FCM) measurement. The highest proportion of membrane-damaged cells was detected in NaOH extraction (26.54% of total cells) while membrane-damaged cells comprised 8.19% of total cells in the control. Copyright © 2014 Elsevier B.V. All rights reserved.

Elasto-plasticity in wrinkled polymerized lipid membranes

KAUST Repository

Chaieb, Sahraoui

2014-01-15

Biomembranes shown to behave like elastic sheets, can also suffer plastic deformations. Neutron scattering experiments on partially polymerised wrinkled membranes revealed that when a critical degree of polymerisation is crossed, the wrinkled membranes do not resume their spherical shapes. Instead they remain wrinkled and rigid while their non-polymerised counterparts resume their spherical floppy shapes. The yield stress of these membranes, measured for the first time via the fractal dimension, is intimately related to the degree of polymerisation probably through a 2D disorder that quenches the lateral diffusion of the lipid molecules. This work might shed light on the physical reason behind the irreversible deformation of echinocytes, acanthocytes and malaria infected red blood cells.

Elasto-plasticity in wrinkled polymerized lipid membranes

KAUST Repository

Chaieb, Saharoui

2014-01-01

Biomembranes shown to behave like elastic sheets, can also suffer plastic deformations. Neutron scattering experiments on partially polymerised wrinkled membranes revealed that when a critical degree of polymerisation is crossed, the wrinkled membranes do not resume their spherical shapes. Instead they remain wrinkled and rigid while their non-polymerised counterparts resume their spherical floppy shapes. The yield stress of these membranes, measured for the first time via the fractal dimension, is intimately related to the degree of polymerisation probably through a 2D disorder that quenches the lateral diffusion of the lipid molecules. This work might shed light on the physical reason behind the irreversible deformation of echinocytes, acanthocytes and malaria infected red blood cells.

Polymeric membranes: surface modification for minimizing (bio)colloidal fouling.

Science.gov (United States)

Kochkodan, Victor; Johnson, Daniel J; Hilal, Nidal

2014-04-01

This paper presents an overview on recent developments in surface modification of polymer membranes for reduction of their fouling with biocolloids and organic colloids in pressure driven membrane processes. First, colloidal interactions such as London-van der Waals, electrical, hydration, hydrophobic, steric forces and membrane surface properties such as hydrophilicity, charge and surface roughness, which affect membrane fouling, have been discussed and the main goals of the membrane surface modification for fouling reduction have been outlined. Thereafter the recent studies on reduction of (bio)colloidal of polymer membranes using ultraviolet/redox initiated surface grafting, physical coating/adsorption of a protective layer on the membrane surface, chemical reactions or surface modification of polymer membranes with nanoparticles as well as using of advanced atomic force microscopy to characterize (bio)colloidal fouling have been critically summarized. Copyright © 2013 Elsevier B.V. All rights reserved.

Polymeric membrane materials: new aspects of empirical approaches to prediction of gas permeability parameters in relation to permanent gases, linear lower hydrocarbons and some toxic gases.

Science.gov (United States)

Malykh, O V; Golub, A Yu; Teplyakov, V V

2011-05-11

Membrane gas separation technologies (air separation, hydrogen recovery from dehydrogenation processes, etc.) use traditionally the glassy polymer membranes with dominating permeability of "small" gas molecules. For this purposes the membranes based on the low free volume glassy polymers (e.g., polysulfone, tetrabromopolycarbonate and polyimides) are used. On the other hand, an application of membrane methods for VOCs and some toxic gas recovery from air, separation of the lower hydrocarbons containing mixtures (in petrochemistry and oil refining) needs the membranes with preferable penetration of components with relatively larger molecular sizes. In general, this kind of permeability is characterized for rubbers and for the high free volume glassy polymers. Data files accumulated (more than 1500 polymeric materials) represent the region of parameters "inside" of these "boundaries." Two main approaches to the prediction of gas permeability of polymers are considered in this paper: (1) the statistical treatment of published transport parameters of polymers and (2) the prediction using model of ≪diffusion jump≫ with consideration of the key properties of the diffusing molecule and polymeric matrix. In the frames of (1) the paper presents N-dimensional methods of the gas permeability estimation of polymers using the correlations "selectivity/permeability." It is found that the optimal accuracy of prediction is provided at n=4. In the frames of the solution-diffusion mechanism (2) the key properties include the effective molecular cross-section of penetrating species to be responsible for molecular transportation in polymeric matrix and the well known force constant (ε/k)(eff i) of {6-12} potential for gas-gas interaction. Set of corrected effective molecular cross-section of penetrant including noble gases (He, Ne, Ar, Kr, Xe), permanent gases (H(2), O(2), N(2), CO), ballast and toxic gases (CO(2), NO(,) NO(2), SO(2), H(2)S) and linear lower hydrocarbons (CH(4

Gamma radiation grafting process for preparing separator membranes for electrochemical cells

International Nuclear Information System (INIS)

Agostino, V.F. D'; Lee, J.Y.

1982-01-01

An irradiation grafting process for preparing separator membranes for use in electrochemical cells, comprises contacting a polymeric base film with an aqueous solution of a hydrophilic monomer and a polymerization retardant; and irradiating said contacted film to form a graft membrane having low electrical resistivity and having monomer molecules uniformly grafted thereon. In the examples (meth) acrylic acid is grafted on to polyethylene, polypropylene and polytetrafluoroethylene in the presence of ferrous sulphate or cupric sulphate as polymerization retardants. (author)

Pyrolytic carbon membranes containing silica: morphological approach on gas transport behavior

Science.gov (United States)

Park, Ho Bum; Lee, Sun Yong; Lee, Young Moo

2005-04-01

Pyrolytic carbon membrane containing silica (C-SiO 2) is a new-class material for gas separation, and in the present work we will deal with it in view of the morphological changes arising from the difference in the molecular structure of the polymeric precursors. The silica embedded carbon membranes were fabricated by a predetermined pyrolysis step using imide-siloxane copolymers (PISs) that was synthesized from benzophenone tetracarboxylic dianhydrides (BTDA), 4,4'-oxydianiline (ODA), and amine-terminated polydimethylsiloxane (PDMS). To induce different morphologies at the same chemical composition, the copolymers were prepared using one-step (preferentially a random segmented copolymer) sand two-step polymerization (a block segmented copolymer) methods. The polymeric precursors and their pyrolytic C-SiO 2 membranes were analyzed using thermal analysis, atomic force microscopy, and transmission electron microscopy, etc. It was found that the C-SiO 2 membrane derived from the random PIS copolymer showed a micro-structure containing small well-dispersed silica domains, whereas the C-SiO 2 membrane from the block PIS copolymer exhibited a micro-structure containing large silica domains in the continuous carbon matrix. Eventually, the gas transport through these C-SiO 2 membranes was significantly affected by the morphological changes of the polymeric precursors.

Polysulfone - CNT composite membrane with enhanced water permeability

Science.gov (United States)

Hirani, Bhakti; Kar, Soumitra; Aswal, V. K.; Bindal, R. C.; Goyal, P. S.

2018-04-01

Polymeric membranes are routinely used for water purification. The performance of these conventional membranes can be improved by incorporating nanomaterials, such as metal oxide nanoparticle and carbon nanotubes (CNTs). This manuscript reports the synthesis and characterization of polysulfone (Psf) based nanocomposite membranes where multi wall carbon nanotubes (MWCNTs) and oleic acid coated Fe3O4 nanoparticles have been impregnated onto the polymeric host matrix. The performance of the membranes was evaluated by water permeability and solute rejection measurements. It was observed that the permeability of Psf membrane increases three times at 0.1% loading of MWCNT without compromise in selectivity. It was further observed that the increase in permeability is not affected upon addition of Fe3O4 nanoparticles into the membrane. In order to get a better insight into the membrane microstructure, small angle neutron scattering (SANS) studies were carried out. There is a good correlation between the water permeability and the pore sizes of the membranes as measured using SANS.

Latest Development on Membrane Fabrication for Natural Gas Purification: A Review

Directory of Open Access Journals (Sweden)

Dzeti Farhah Mohshim

2013-01-01

Full Text Available In the last few decades, membrane technology has been a great attention for gas separation technology especially for natural gas sweetening. The intrinsic character of membranes makes them fit for process escalation, and this versatility could be the significant factor to induce membrane technology in most gas separation areas. Membranes were synthesized with various materials which depended on the applications. The fabrication of polymeric membrane was one of the fastest growing fields of membrane technology. However, polymeric membranes could not meet the separation performances required especially in high operating pressure due to deficiencies problem. The chemistry and structure of support materials like inorganic membranes were also one of the focus areas when inorganic membranes showed some positive results towards gas separation. However, the materials are somewhat lacking to meet the separation performance requirement. Mixed matrix membrane (MMM which is comprising polymeric and inorganic membranes presents an interesting approach for enhancing the separation performance. Nevertheless, MMM is yet to be commercialized as the material combinations are still in the research stage. This paper highlights the potential promising areas of research in gas separation by taking into account the material selections and the addition of a third component for conventional MMM.

Modelling and essay or the polarization curve of a polymeric membrane fuel cell; Modelagem e ensaio da curva de polarizacao de uma celula a combustivel de membrana polimerica

Energy Technology Data Exchange (ETDEWEB)

Almeida, Silvio Carlos Anibal de; Xavier, Bruno Domont; Gatti, George Cassani; Ribeiro, Rodrigo Minguita [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Mecanica]. E-mails: silvioa@gmail.com; brunodomont@gmail.com; gatti_ufrj@yahoo.com.br; rminguita@yahoo.com.br; Furtado, Jose Geraldo de Melo [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil). Dept. de Tecnologias Especiais]. E-mail: furtado@cepel.br

2006-07-01

This paper describes the essays performed with a polymeric membrane fuel cell (PEMFC) at the test laboratories of the ELETROBRAS Electric Energy Research Center (CEPEL/ELETROBRAS) manufactured by the Eletrocell, which allows to study the influence of some functional parameters (voltage, current, mass and pressure fluxes)

Autocatalytic polymerization generates persistent random walk of crawling cells.

Science.gov (United States)

Sambeth, R; Baumgaertner, A

2001-05-28

The autocatalytic polymerization kinetics of the cytoskeletal actin network provides the basic mechanism for a persistent random walk of a crawling cell. It is shown that network remodeling by branching processes near the cell membrane is essential for the bimodal spatial stability of the network which induces a spontaneous breaking of isotropic cell motion. Details of the phenomena are analyzed using a simple polymerization model studied by analytical and simulation methods.

Method of Making Reaction Induced Phase Separation Membranes and Uses Thereof

KAUST Repository

Peinemann, Klaus-Viktor; Aburabie, Jamaliah Hani; Villalobos, Luis Francisco

2017-01-01

Provided herein are methods of making asymmetric membranes comprising a first layer and a second layer. The methods include preparing a polymeric solution comprising one or more polymers, casting the polymeric solution to form a polymeric film

Gas separation membranes

Science.gov (United States)

Schell, William J.

1979-01-01

A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

Biomimetic aquaporin membranes coming of age

DEFF Research Database (Denmark)

Tang, Chuyang; Wang, Zhining; Petrinić, Irena

2015-01-01

Membrane processes have been widely used for water purification because of their high stability, efficiency, low energy requirement and ease of operation. Traditional desalting membranes are mostly dense polymeric films with a "trade off" effect between permeability and selectivity. Biological...

The tempered polymerization of human neuroserpin.

Directory of Open Access Journals (Sweden)

Rosina Noto

Full Text Available Neuroserpin, a member of the serpin protein superfamily, is an inhibitor of proteolytic activity that is involved in pathologies such as ischemia, Alzheimer's disease, and Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB. The latter belongs to a class of conformational diseases, known as serpinopathies, which are related to the aberrant polymerization of serpin mutants. Neuroserpin is known to polymerize, even in its wild type form, under thermal stress. Here, we study the mechanism of neuroserpin polymerization over a wide range of temperatures by different techniques. Our experiments show how the onset of polymerization is dependent on the formation of an intermediate monomeric conformer, which then associates with a native monomer to yield a dimeric species. After the formation of small polymers, the aggregation proceeds via monomer addition as well as polymer-polymer association. No further secondary mechanism takes place up to very high temperatures, thus resulting in the formation of neuroserpin linear polymeric chains. Most interesting, the overall aggregation is tuned by the co-occurrence of monomer inactivation (i.e. the formation of latent neuroserpin and by a mechanism of fragmentation. The polymerization kinetics exhibit a unique modulation of the average mass and size of polymers, which might suggest synchronization among the different processes involved. Thus, fragmentation would control and temper the aggregation process, instead of enhancing it, as typically observed (e.g. for amyloid fibrillation.

Synthesis of Nanogels via Cell Membrane-Templated Polymerization.

Science.gov (United States)

Zhang, Jianhua; Gao, Weiwei; Fang, Ronnie H; Dong, Anjie; Zhang, Liangfang

2015-09-09

The synthesis of biomimetic hydrogel nanoparticles coated with a natural cell membrane is described. Compared to the existing strategy of wrapping cell membranes onto pre-formed nanoparticle substrates, this new approach forms the cell membrane-derived vesicles first, followed by growing nanoparticle cores in situ. It adds significant controllability over the nanoparticle properties and opens unique opportunities for a broad range of biomedical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Manufacturing microporous membrane by polymerisation

International Nuclear Information System (INIS)

Tanny, G.B.

1984-01-01

The starting materials for the practice of the present invention are (1) one or more organic monomers or oligomers which upon irradiation very rapidly undergo a polymerization reaction to form a solid polymer; and (2) a liquid vehicle in which the one or more organic monomers or oligomers are soluble but in which the polymer formed is insoluble. For the manufacture of microporous membrane in accordance with the invention the monomers or oligomers are dissolved in the liquid vehicle, the resulting solution is formed into a thin layer, and the thin layer of the solution is then irradiated as with ultraviolet or electron beam radiation whereupon the rapid polymerization reaction immediately ensues and the polymer formed immediately segregates from the vehicle thereby resulting in microporous membrane from which the vehicle can be removed as by evaporation or washing. Because the radiation-induced polymerization reaction and the segregation of the polymer formed are so rapid, the membrane formed has cells and communications therebetween of very small dimensions thereby providing the microporous structure. Where ultra-violet radiation is used the solution also includes a photo-initiator. (author)

Progress of Nanocomposite Membranes for Water Treatment

Directory of Open Access Journals (Sweden)

Claudia Ursino

2018-04-01

Full Text Available The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

Progress of Nanocomposite Membranes for Water Treatment.

Science.gov (United States)

Ursino, Claudia; Castro-Muñoz, Roberto; Drioli, Enrico; Gzara, Lassaad; Albeirutty, Mohammad H; Figoli, Alberto

2018-04-03

The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

Electrochemical Characterization of a Polymer Inclusion Membrane Made of Cellulose Triacetate and Aliquat 336 and Its Application to Sulfonamides Separation

Directory of Open Access Journals (Sweden)

Juana Benavente

2018-01-01

Full Text Available An electrochemical characterization of a polymer inclusion membrane (PIM fabricated with the ionic liquid (IL Aliquat 336 (26% and the polymer cellulose triacetate (CTA (76% is presented. Considering the use of PIMs in separation systems to remove pollutants from water, the characterization was performed with NaCl solutions by measuring membrane potential, electrochemical impedance spectroscopy, and salt diffusion and results were compared with those obtained from dry membranes. Results showed a significant reduction in the membrane diffusive permeability and electrical conductivity as well as the transport number of cation Na+ across the PIM when compared with solution values, which could be mainly related to the dense character of the membrane. Membrane application in the separation of different sulfonamides (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole from water, with 1 M NaCl solution as striping phase, was also considered. These results indicated that the different chemical characteristics of the compounds, as well as the compact structure of the PIM, limited the transport of the organic molecules though it.

Post-Synthetic Polymerization of UiO-66-NH2 Nanoparticles and Polyurethane Oligomer toward Stand-Alone Membranes for Dye Removal and Separation.

Science.gov (United States)

Yao, Bing-Jian; Jiang, Wei-Ling; Dong, Ying; Liu, Zhi-Xian; Dong, Yu-Bin

2016-07-18

Metal-organic frameworks (MOFs) are widely used as porous materials in the fields of adsorption and separation. However, their practical application is largely hindered by limitations to their processability. Herein, new UiO-66-Urea-based flexible membranes with MOF loadings of 50 (1), 60 (2), and 70 wt % (3) were designed and prepared by post-synthetic polymerization of UiO-66-NH2 nanoparticles and a polyurethane oligomer under mild conditions. The adsorption behavior of membrane 3 towards four hydrophilic dyes, namely, eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB), in aqueous solution was studied in detail. It exhibits strong adsorption of EY and RB but weak adsorption of MG and MB in aqueous solution. Owing to the selective adsorption of these hydrophilic dyes, membrane 3 can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures in aqueous solution. In addition, the membrane is uniformly textured, easily handled, and can be reused for dye adsorption and separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ceramic membrane in production of recycled water; Keraamikalvo uusioveden valmistuksessa - EKT 05

Energy Technology Data Exchange (ETDEWEB)

Laitinen, N.; Luonsi, A.; Levaenen, E.; Maentylae, T.; Vilen, J. [Haemeen ympaeristoekeskus, Tampere (Finland)

1998-12-31

Applicability of ceramic ultrafiltration membrane modifications were studied with laboratory units to purify clear filtrate and biologically treated combined wastewater from high quality board manufacturing process for reuse. Also performance of polymeric membrane and ceramic membrane was compared. The performance of the membrane filtration cell, developed according to requirements of the fixed dimensions of ceramic membrane was compared with the performance of the cross-rotational commercial test unit (CR-filter) of polymeric membranes. The quality of ultrafiltration permeate, namely suspended solids, turbidity and colour, was better than the quality of lake water used in the mill. The permeate fluxes were in the range of 60-75 l/m{sup 2}h. The fouling layer primarily controlled the flux and the retention, leaving the effects of surface modifications as the secondary function. The flux was slightly higher with the biologically treated wastewater. Differences in membrane material and pore size had an effect on the cleaning ability of the membranes. The polymeric membrane and the membrane with smaller pore size were easier to clean. Tests with the CR-filter showed that the rotor increases shear forces, reduces the filtration resistance and thus increases the flux compared to the cell for ceramic membranes where the increase of shear forces can be done by increasing the flow velocities. (orig.)

Ceramic membrane in production of recycled water; Keraamikalvo uusioveden valmistuksessa - EKT 05

Energy Technology Data Exchange (ETDEWEB)

Laitinen, N; Luonsi, A; Levaenen, E; Maentylae, T; Vilen, J [Haemeen ympaeristoekeskus, Tampere (Finland)

1999-12-31

Applicability of ceramic ultrafiltration membrane modifications were studied with laboratory units to purify clear filtrate and biologically treated combined wastewater from high quality board manufacturing process for reuse. Also performance of polymeric membrane and ceramic membrane was compared. The performance of the membrane filtration cell, developed according to requirements of the fixed dimensions of ceramic membrane was compared with the performance of the cross-rotational commercial test unit (CR-filter) of polymeric membranes. The quality of ultrafiltration permeate, namely suspended solids, turbidity and colour, was better than the quality of lake water used in the mill. The permeate fluxes were in the range of 60-75 l/m{sup 2}h. The fouling layer primarily controlled the flux and the retention, leaving the effects of surface modifications as the secondary function. The flux was slightly higher with the biologically treated wastewater. Differences in membrane material and pore size had an effect on the cleaning ability of the membranes. The polymeric membrane and the membrane with smaller pore size were easier to clean. Tests with the CR-filter showed that the rotor increases shear forces, reduces the filtration resistance and thus increases the flux compared to the cell for ceramic membranes where the increase of shear forces can be done by increasing the flow velocities. (orig.)

Ion-conducting membranes

Science.gov (United States)

Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

2017-12-26

An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

Controlled change of transport properties of poly(ethylene terephthalate) track membranes by plasma method

International Nuclear Information System (INIS)

Kravets, L I; Dmitriev, S N; Drachev, A I; Gilman, A B; Lazea, A; Dinescu, G

2007-01-01

A process of plasma polymerization of dimethylaniline and acrylic acid vapours on the surface of poly(ethylene terephthalate) track membranes has been investigated. The surface and hydrodynamic properties of the composite membranes produced in this case have been studied. It is shown that the water permeability of the obtained polymeric membranes can be controlled by changing the filtrate pH. Membranes with such properties can be used for controllable drug delivery and in sensor control

Polymeric membranes obtained from S-PEEK for application in PEM fuel cells; Caracterizacao de membranas polimericas obtidas a partir dos S-PEEK para aplicacao em celulas combustiveis do tipo PEM

Energy Technology Data Exchange (ETDEWEB)

Barreto, Ednardo G.; Fiuza, Raildo A.; Catao, Ronei S.; Jose, Nadia M.; Boaventura, Jaime S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: ednardobarreto@yahoo.com.br, e-mail: raildofiuza@gmail.com, e-mail: roneicatao@ig.com.br, e-mail: nadia@ufba.br, e-mail: bventura@ufba.br; Pepe, Yuri [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Fisica

2007-07-01

This work had the objective to develop and to characterize S-PEEK membranes (sulfonated poly ether ether ketone) through chemical and electrochemical analyses. Conductivity test in function of the frequency and tension had been carried through; as well as, the open circuit tension of a fuel cell using the S-PEEK as electrolyte. Additional tests included TGA (Thermogravimetric Analysis), water absorption test, DSC (Differential Scanning Calorimetry), as tools to characterize conducting, thermal and mechanical proprieties of polymeric membrane. (author)

Forward osmosis biomimetic membranes in industrial and environmental applications

DEFF Research Database (Denmark)

Madsen, Henrik Tækker; Søgaard, Erik Gydesen; Bajraktari, Niada

Membrane processes have in recent years found increasing uses in several sectors where separation of one or more components from a solvent, typically water, is required. The most widespread types of membranes are polymeric and pressure driven, but the high pressures that are required results...... consumption and lead to much more stable operations, but is currently limited by the availability of suitable membranes. However, by introducing aquaporin protein channels into a polymeric membrane to make a biomimetic membrane, the vision of both high flux and separation efficiency may be achieved......) a single use filtration module containing a sample reservoir and a biomimetic aquaporin based forward osmosis membrane. 2) a multi-use desktop forward osmosis system containing draw solution mixing, and monitoring devices. The sample is placed in the single use module and the module is then mounted...

Separation and preconcentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin in blood samples by inclusion emulsion membranes and its determination by gas chromatography.

Science.gov (United States)

Mokhtari, Bahram; Pourabdollah, Kobra

2012-10-15

The nano-mediated preconcentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin from blood samples was reported by inclusion-facilitated emulsion liquid membrane process. The novelty of this study was application of nano-baskets of calixarene and emulsion liquid membranes in selective and efficient preconcentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin. For this aim, four derivatives of p-tert-calix[4]arene bearing different sulfonamide moieties were synthesized and their inclusion-extraction parameters were optimized including calixarenes' scaffold and concentration (3, 4 wt%), diluent type in membrane, phase and treat ratios (0.8 and 0.3), mixing speed (300 rpm), and initial solute concentrations (0.1-10 pg g(-1)). The extraction efficiency was determined by dioxin's concentration using gas chromatography equipped with electron capture detector and the results revealed that in optimized operating conditions, the preconcentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin was improved and the limit of detection decreased. Copyright © 2012 Elsevier B.V. All rights reserved.

Tunable Nanocomposite Membranes for Water Remediation and Separations

Science.gov (United States)

Sierra, Sebastian Hernandez

Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes. Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these responsive materials prevent the loss of nanomaterials to the environment and improve reactivity due to their larger surface areas, expanding their range of applications. The present work describes different techniques used to create nanocomposites based on poly(vinylidene fluoride) (PVDF) hollow fiber and flat sheet membranes, both thick sponge-like and thin. Due to their hydrophobicity, hollow fiber membranes were hydrophilized by a water-based green process of cross-linking polyvinylpyrrolidone (PVP) onto their surface. Commercial hydrophilic and hydrophilized lab-prepared membranes were subsequently functionalized with a poly(acrylic acid) (PAA) hydrogel through free radical polymerizations. This work advanced membrane functionalization, specifically flat sheet membranes, from lab-scale to full-scale by modifications of the polymerization procedures. The hydrogel functionalized membranes by redox polymerization showed an expected responsive behavior, represented by permeability variation at various pH values (4.0 ≤ pH ≤ 9.0), from 53.9 to 3.4 L/(m2EhEbar) and a change in effective pore size from 222 to 111 nm, being 3800 L/(m 2EhEbar) and 650 nm the former permeability and pore size values of the

Characterization of the proton binding sites of extracellular polymeric substances in an anaerobic membrane bioreactor.

Science.gov (United States)

Liu, Yi; Chang, Sheng; Defersha, Fantahun M

2015-07-01

This paper focuses on the characterization of the chemical compositions and acidic constants of the extracellular polymeric substances (EPSs) in an anaerobic membrane bioreactor treating synthetic brewery wastewater by using chemical analysis, linear programming analysis (LPA) of titration data, and FT-IR analysis. The linear programming analysis of titration data revealed that the EPSs have proton binding sites with pKa values from pKa ≤ 6, between 6 and 7, and approximately 9.8. The strong acidic sites (pKa ≤ 6) and some weak acidic sites (7.5 membrane filtration. In addition, the FT-IR analysis confirmed the presence of proteins, carbohydrates, nucleic acids, and lipids in the EPS samples. Based on the FT-IR analysis and the main chemical functional groups at the bacterial cell surfaces, the identified proton binding sites were related to carboxyl, phosphate, and hydroxyl/amine groups with pKa values of 4.6 ± 0.7, 6.6 ± 0.01, and 9.7 ± 0.1, respectively, with the corresponding respective intensities of 0.31 ± 0.05, 0.96 ± 0.3, and 1.53 ± 0.3 mmole/g-EPS. The pKa values and intensities of the proton binding sites are the fundamental molecular properties of EPSs that affect the EPS charge, molecular interactions, and metal complexation characteristics. Determination of such properties can advance Derjaguin-Landau-Verwey-Overbeek (DLVO)-based concentration polarization modeling, facilitate the estimation of the osmotic pressure of the EPS concentration polarization layers, and lead to a deeper understanding of the role of metal complexation in membrane fouling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Crystal structure of an orthomyxovirus matrix protein reveals mechanisms for self-polymerization and membrane association.

Science.gov (United States)

Zhang, Wenting; Zheng, Wenjie; Toh, Yukimatsu; Betancourt-Solis, Miguel A; Tu, Jiagang; Fan, Yanlin; Vakharia, Vikram N; Liu, Jun; McNew, James A; Jin, Meilin; Tao, Yizhi J

2017-08-08

Many enveloped viruses encode a matrix protein. In the influenza A virus, the matrix protein M1 polymerizes into a rigid protein layer underneath the viral envelope to help enforce the shape and structural integrity of intact viruses. The influenza virus M1 is also known to mediate virus budding as well as the nuclear export of the viral nucleocapsids and their subsequent packaging into nascent viral particles. Despite extensive studies on the influenza A virus M1 (FLUA-M1), only crystal structures of its N-terminal domain are available. Here we report the crystal structure of the full-length M1 from another orthomyxovirus that infects fish, the infectious salmon anemia virus (ISAV). The structure of ISAV-M1 assumes the shape of an elbow, with its N domain closely resembling that of the FLUA-M1. The C domain, which is connected to the N domain through a flexible linker, is made of four α-helices packed as a tight bundle. In the crystal, ISAV-M1 monomers form infinite 2D arrays with a network of interactions involving both the N and C domains. Results from liposome flotation assays indicated that ISAV-M1 binds membrane via electrostatic interactions that are primarily mediated by a positively charged surface loop from the N domain. Cryoelectron tomography reconstruction of intact ISA virions identified a matrix protein layer adjacent to the inner leaflet of the viral membrane. The physical dimensions of the virion-associated matrix layer are consistent with the 2D ISAV-M1 crystal lattice, suggesting that the crystal lattice is a valid model for studying M1-M1, M1-membrane, and M1-RNP interactions in the virion.

Composite materials with ionic conductivity: from inorganic composites to hybrid membranes

Energy Technology Data Exchange (ETDEWEB)

Yaroslavtsev, Andrei B [N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

2009-11-30

Information on composite materials with ionic conductivity including inorganic composites and hybrid polymeric ion exchange membranes containing inorganic or polymeric nanoparticles is generalized. The nature of the effect of increase in the ionic conductivity in this type of materials and the key approaches used for theoretical estimation of the conductivity are considered. Data on the ionic conductivity and some other important properties of composites and membrane materials are presented. Prospects for utilization of composite materials and hybrid membranes in hydrogen power engineering are briefly outlined.

Preparation and characterization of polymer inclusion membrane based optode for determination of Al{sup 3+} ion

Energy Technology Data Exchange (ETDEWEB)

Suah, Faiz Bukhari Mohd, E-mail: fsuah@usm.my [School of Chemical Sciences, Universiti Sains Malaysia, 11800, Minden, Pulau Pinang (Malaysia); Ahmad, Musa [Faculty of Science & Technology, Universiti Sains Islam Malaysia, 71800, Bandar Baru Nilai, Negeri Sembilan (Malaysia)

2017-01-25

The use of a polymer inclusion membrane (PIM) as a sensing material is a new approach to overcome the selectivity and stability drawbacks of the optical chemical sensor (optode). In this study, non-plasticized PIM containing poly(vinyl chloride) as a support base, sodium morin-5-sulfonate (NaMSA) as a reagent and Aliquat 336 as a fixed carrier (ionophore) was prepared and its performance was tested for application in an optode to determine Al{sup 3+} ions. The results showed that PIM properties are greatly influenced by the membrane composition. The studies revealed that the optode response was dependent on film thickness, the presence of plasticizer, stirring effect, concentration of NaMSA, concentration of Aliquat 336 and pH of the aqueous solution used. The dynamic range of Al{sup 3+} ions concentration determined using this optode was linear from 5.19 × 10{sup −7} to 6.00 × 10{sup −5} mol L{sup −1} and the calculated limit of detection (L.O.D.) was found to be 4.07 × 10{sup −7} mol L{sup −1}. The maximum emission wavelength (λ{sub em}) for the PIM based optode was 512 nm. Scanning electron microscopy analysis of the PIM revealed that a dense texture was formed. Fourier transform infra-red and thermal gravimetry analysis characterizations proved that all of the constituents of the PIM remain within the membrane. The PIM developed in this work was found to be stable, has good mechanical strength, and is sensitive and reusable. Lastly, the PIM was successfully applied as an optical sensor for determination of Al{sup 3+} ions in an aqueous solution. - Highlights: • A novel non-plasticized polymer inclusion membrane (PIM) based optode has been developed for determination of Al{sup 3+} ions. • A novel use of sulphonated morin (NaMSA) for determination of Al{sup 3+} ions by using fluorescence technique. • The optode is fully reversible. • It shows good repeatability and reproducibility without significant decrease in fluorescence

Surface modification of polysulfone membranes applied for a membrane reactor with immobilized alcohol dehydrogenase

DEFF Research Database (Denmark)

Hoffmann, Christian; Silau, Harald; Pinelo, Manuel

2018-01-01

activated by lithiation followed by functionalization with acid chlorides at 0 °C, permitting modification of commercial PSf membranes without compromising the mechanical integrity of the membrane. Post-functionalization polymer grafting was illustrated through both, a “grafting from” approach by surface...... initiated atom transfer radical polymerization (SI-ATRP) and by a “grafting to” approach exploiting Cu(I) catalyzed 1,3-cycloadditions of alkynes with azides (CuAAC) introducing hydrophilic polymers onto the membrane surface. Poly(1-vinyl imidazole) (pVim) grafted membranes were exploited as support...

Structural Study and Modification of Support Layer for Forward Osmosis Membranes

KAUST Repository

Shi, Meixia

2016-01-01

polymerization. Among the different substrates we include standard asymmetric porous membranes prepared from homopolymers, such as polysulfone. Additionally block copolymer membrane and Anodisc alumina membrane are chosen based on their exceptional structures

Polymeric composite membranes for temperature and pH-responsive delivery of doxorubicin hydrochloride

Directory of Open Access Journals (Sweden)

Sahar Mohamaddoust Aliabadi

2015-07-01

Full Text Available Objective(s: Nowadays hydrogels are one of the upcoming classes of polymer-based controlled-release drug delivery systems. Temperature and pH-responsive delivery systems have drawn much attention because some diseases reveal themselves by a change in temperature and/or pH. The objective of this work is to prepare and characterize composite membrane using responsive nanoparticles into a polymer matrix. Materials and Methods: These nanoparticles were made of the copolymer poly (N-isopropylacrylamide-co-methaçrylic acid by an aqueous dispersion polymerization process and are responsible for dual sensitivity to temperature and pH. Morphology study with SEM, swelling behavior with Dynamic Light Scattering Technique, in vitro drug release behavior with side-by-side Diffusion Cells were also investigated in this paper. Doxorubicin hydrochloride was used as a model solute. Results:The study on the release of doxorubicin hydrochloride showed that the release rate was higher at pH 5 than pH 7.4, increased with the increase of temperature. Nevertheless, ionic strength only poses a minor direct effect at higher pH. Conclusion:Such system may be potentially used as a tumor-targeting doxorubicin hydrochloride delivery in the body.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle.

Science.gov (United States)

Singh, Ashok K; Singh, Prerna

2010-08-24

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L(1)) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L(2)) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L(2):PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L(2) was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3x10(-8) mol L(-1) for PME and 7.7x10(-9) mol L(-1) for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples. 2010 Elsevier B.V. All rights reserved.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle

Energy Technology Data Exchange (ETDEWEB)

Singh, Ashok K., E-mail: akscyfcy@iitr.ernet.in [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India); Singh, Prerna [Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee 247 667 (India)

2010-08-24

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L{sub 1}) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate- 1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L{sub 2}) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L{sub 2}:PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L{sub 2} was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3 x 10{sup -8} mol L{sup -1} for PME and 7.7 x 10{sup -9} mol L{sup -1} for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples.

Determination of cerium ion by polymeric membrane and coated graphite electrode based on novel pendant armed macrocycle

International Nuclear Information System (INIS)

Singh, Ashok K.; Singh, Prerna

2010-01-01

Plasticized membranes using 2,3,4:12,13,14-dipyridine-1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L 1 ) and 2,3,4:12,13,14-dipyridine-1,5,8,11,15,18-hexamethylacrylate- 1,3,5,8,11,13,15,18-octaazacycloicosa-2,12-diene (L 2 ) have been prepared and explored as Ce(III) selective sensors. Effect of various plasticizers viz. dibutylphthalate (DBP), tri-n-butylphthalate (TBP), o-nitrophenyloctylether (o-NPOE), dioctylphthalate (DOP), benzylacetate (BA) and anion excluders, sodium tetraphenylborate (NaTPB) and potassium tetrakis p-(chlorophenyl) borate was studied in detail and improved performance was observed. Optimum performance was observed for the membrane sensor having a composition of L 2 :PVC:o-NPOE:KTpClPB in the ratio of 6:34:58:2 (w/w, mg). The performance of the membrane based on L 2 was compared with polymeric membrane electrode (PME) as well as with coated graphite electrode (CGE). The electrodes exhibit Nernstian slope for Ce(III) ions with limits of detection of 8.3 x 10 -8 mol L -1 for PME and 7.7 x 10 -9 mol L -1 for CGE. The response time for PME and CGE was found to be 12 s and 10 s respectively. The potentiometric responses are independent of the pH of the test solution in the pH range 3.5-7.5 for PME and 2.5-8.5 for CGE. The CGE could be used for a period of 5 months. The practical utility of the CGE has been demonstrated by its usage as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce(III) solution. The proposed electrode was also successfully applied to the determination of fluoride ions in mouthwash solution and oxalate ions in real samples.

Separation performance and interfacial properties of nanocomposite reverse osmosis membranes

KAUST Repository

Pendergast, MaryTheresa M.; Ghosh, Asim K.; Hoek, E.M.V.

2013-01-01

Four different types of nanocomposite reverse osmosis (RO) membranes were formed by interfacial polymerization of either polyamide (PA) or zeolite A-polyamide nanocomposite (ZA-PA) thin films over either pure polysulfone (PSf) or zeolite A-polysulfone nanocomposite (ZA-PSf) support membranes cast by wet phase inversion. All three nanocomposite membranes exhibited superior separation performance and interfacial properties relative to hand-cast TFC analogs including: (1) smoother, more hydrophilic surfaces (2) higher water permeability and salt rejection, and (3) improved resistance to physical compaction. Less compaction occurred for membranes with nanoparticles embedded in interfacially polymerized coating films, which adds further proof that flux decline associated with physical compaction is influenced by coating film properties in addition to support membrane properties. The new classes of nanocomposite membrane materials continue to offer promise of further improved RO membranes for use in desalination and advanced water purification. © 2011 Elsevier B.V.

High-definition polymeric membranes: construction of 3D lithographed channel arrays through control of natural building blocks dynamics.

Science.gov (United States)

Speranza, Valentina; Trotta, Francesco; Drioli, Enrico; Gugliuzza, Annarosa

2010-02-01

The fabrication of well-defined interfaces is in high demand in many fields of biotechnologies. Here, high-definition membrane-like arrays are developed through the self-assembly of water droplets, which work as natural building blocks for the construction of ordered channels. Solution viscosity together with the dynamics of the water droplets can decide the final formation of three-dimensional well-ordered patterns resembling anodic structures, especially because solvents denser than water are used. Particularly, the polymer solution viscosity is demonstrated to be a powerful tool for control of the mobility of submerged droplets during the microfabrication process. The polymeric patterns are structured at very high levels of organization and exhibit well-established transport-surface property relationships, considered basics for any types of advanced biotechnologies.

Review of Membranes for Helium Separation and Purification

Directory of Open Access Journals (Sweden)

Colin A. Scholes

2017-02-01

Full Text Available Membrane gas separation has potential for the recovery and purification of helium, because the majority of membranes have selectivity for helium. This review reports on the current state of the research and patent literature for membranes undertaking helium separation. This includes direct recovery from natural gas, as an ancillary stage in natural gas processing, as well as niche applications where helium recycling has potential. A review of the available polymeric and inorganic membranes for helium separation is provided. Commercial gas separation membranes in comparable gas industries are discussed in terms of their potential in helium separation. Also presented are the various membrane process designs patented for the recovery and purification of helium from various sources, as these demonstrate that it is viable to separate helium through currently available polymeric membranes. This review places a particular focus on those processes where membranes are combined in series with another separation technology, commonly pressure swing adsorption. These combined processes have the most potential for membranes to produce a high purity helium product. The review demonstrates that membrane gas separation is technically feasible for helium recovery and purification, though membranes are currently only applied in niche applications focused on reusing helium rather than separation from natural sources.

Reverse osmosis membrane of high urea rejection properties. [water purification

Science.gov (United States)

Johnson, C. C.; Wydeven, T. J. (Inventor)

1980-01-01

Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

Membrane and Nuclear Permeabilization by Polymeric pDNA Vehicles: Efficient Method for Gene Delivery or Mechanism of Cytotoxicity?

Science.gov (United States)

Grandinetti, Giovanna; Smith, Adam E.; Reineke, Theresa M.

2012-01-01

The aim of this study is to compare the cytotoxicity mechanisms of linear PEI to two analogous polymers synthesized by our group: a hydroxyl-containing poly(L-tartaramidoamine) (T4) and a version containing an alkyl chain spacer poly(adipamidopentaethylenetetramine) (A4) by studying the cellular responses to polymer transfection. We have also synthesized analogues of T4 with different molecular weights (degrees of polymerization of 6, 12, and 43) to examine the role of molecular weight on the cytotoxicity mechanisms. Several mechanisms of polymer-induced cytotoxicity are investigated, including plasma membrane permeabilization, the formation of potentially harmful polymer degradation products during transfection including reactive oxygen species, and nuclear membrane permeabilization. We hypothesized that since cationic polymers are capable of disrupting the plasma membrane, they may also be capable of disrupting the nuclear envelope, which could be a potential mechanism of how the pDNA is delivered into the nucleus (other than nuclear envelope breakdown during mitosis). Using flow cytometry and confocal microscopy, we show that the polycations with the highest amount of protein expression and toxicity, PEI and T443, are capable of inducing nuclear membrane permeability. This finding is important for the field of nucleic acid delivery in that not only could direct nucleus permeabilization be a mechanism for pDNA nuclear import but also a potential mechanism of cytotoxicity and cell death. We also show that the production of reactive oxygen species is not a main mechanism of cytotoxicity, and that the presence or absence of hydroxyl groups as well as polymer length plays a role in polyplex size and charge in addition to protein expression efficiency and toxicity. PMID:22175236

EXTRACTION DU Cr(VI PAR MEMBRANE POLYMERE A INCLUSION

Directory of Open Access Journals (Sweden)

O KEBICHE SENHADJI

2008-06-01

Le pH de la solution aqueuse constituant la phase source est un paramètre clé dans l’opération de transport du Cr(VI à travers les MPIs étudiées. Un pH de 1,2 est recommandé pour la réalisation de l’extraction dans les conditions optimales déterminées.

Application of radiation-induced graft polymerization to preparation of functional materials

International Nuclear Information System (INIS)

Sugo, Takanobu

2010-01-01

Radiation-induced graft polymerization is a powerful method for appending various functionalities onto existing fabrics, nonwoven fabrics, fibers, membranes, and beads while maintaining the shape and mechanical strength. By using this method, the author has developed and commercialized functional polymeric materials over 45 years. The materials produced by the fruits of radiation chemistry contributed to the improvement of our lives and environments and the collection of rare metal resources. (author)

Thin porphyrin composite membranes with enhanced organic solvent transport

KAUST Repository

Phuoc, Duong; Anjum, Dalaver H.; Peinemann, Klaus-Viktor; Nunes, Suzana Pereira

2018-01-01

Extending the stability of polymeric membranes in organic solvents is important for applications in chemical and pharmaceutical industry. Thin-film composite membranes with enhanced solvent permeance are proposed, using porphyrin as a building block

Comparison and analysis of membrane fouling between flocculent sludge membrane bioreactor and granular sludge membrane bioreactor.

Directory of Open Access Journals (Sweden)

Wang Jing-Feng

Full Text Available The goal of this study is to investigate the effect of inoculating granules on reducing membrane fouling. In order to evaluate the differences in performance between flocculent sludge and aerobic granular sludge in membrane reactors (MBRs, two reactors were run in parallel and various parameters related to membrane fouling were measured. The results indicated that specific resistance to the fouling layer was five times greater than that of mixed liquor sludge in the granular MBR. The floc sludge more easily formed a compact layer on the membrane surface, and increased membrane resistance. Specifically, the floc sludge had a higher moisture content, extracellular polymeric substances concentration, and negative surface charge. In contrast, aerobic granules could improve structural integrity and strength, which contributed to the preferable permeate performance. Therefore, inoculating aerobic granules in a MBR presents an effective method of reducing the membrane fouling associated with floc sludge the perspective of from the morphological characteristics of microbial aggregates.

Membrane-based ethylene/ethane separation: The upper bound and beyond

KAUST Repository

Rungta, Meha; Zhang, Chen; Koros, William J.; Xu, Liren

2013-01-01

Ethylene/ethane separation via cryogenic distillation is extremely energy-intensive, and membrane separation may provide an attractive alternative. In this paper, ethylene/ethane separation performance using polymeric membranes is summarized

The use of a polymer inclusion membrane for separation and preconcentration of orthophosphate in flow analysis

International Nuclear Information System (INIS)

Nagul, Edward A.; Fontàs, Clàudia; McKelvie, Ian D.; Cattrall, Robert W.; Kolev, Spas D.

2013-01-01

Graphical abstract: -- Highlights: •A flow analysis system determines phosphate at trace levels as molybdenum blue. •The flow system can operate under flow injection or continuous flow conditions. •On-line membrane-based separation and preconcentration is applied. •A polymer inclusion membrane composed of 70 wt% PVC and 30 wt% Aliquat 336 is used. •The flow system was successfully applied to a number of pristine water samples. -- Abstract: A highly sensitive flow analysis system has been developed for the trace determination of reactive phosphate in natural waters, which uses a polymer inclusion membrane (PIM) with Aliquat 336 as the carrier for on-line analyte separation and preconcentration. The system operates under flow injection (FI) and continuous flow (CF) conditions. Under optimal FI conditions the system is characterised by a linear concentration range between 0.5 and 1000 μg L −1 P, a sampling rate of 10 h −1 , a limit of detection of 0.5 μg L −1 P and RSDs of 3.2% (n = 10, 100 μg L −1 ) and 7.7% (n = 10, 10 μg L −1 ). Under CF conditions with 10 min stop-flow time and sample solution flow rate of 1.32 mL min −1 the flow system offers a limit of detection of 0.04 μg L −1 P, a sampling rate of 5 h −1 and an RSD of 3.4% (n = 5, 2.0 μg L −1 ). Interference studies revealed that anions commonly found in natural waters did not interfere when in excess of at least one order of magnitude. The flow system, operating under CF conditions, was successfully applied to the analysis of natural water samples containing concentrations of phosphate in the low μg L −1 P range, using the multipoint standard addition method

The use of a polymer inclusion membrane for separation and preconcentration of orthophosphate in flow analysis

Energy Technology Data Exchange (ETDEWEB)

Nagul, Edward A. [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia); Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Victoria 3010 (Australia); Fontàs, Clàudia [Department of Chemistry, University of Girona, Campus Montilivi, 17071 Girona (Spain); McKelvie, Ian D. [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia); School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth PL48AA (United Kingdom); Cattrall, Robert W. [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia); Kolev, Spas D., E-mail: s.kolev@unimelb.edu.au [School of Chemistry, The University of Melbourne, Victoria 3010 (Australia); Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Victoria 3010 (Australia)

2013-11-25

Graphical abstract: -- Highlights: •A flow analysis system determines phosphate at trace levels as molybdenum blue. •The flow system can operate under flow injection or continuous flow conditions. •On-line membrane-based separation and preconcentration is applied. •A polymer inclusion membrane composed of 70 wt% PVC and 30 wt% Aliquat 336 is used. •The flow system was successfully applied to a number of pristine water samples. -- Abstract: A highly sensitive flow analysis system has been developed for the trace determination of reactive phosphate in natural waters, which uses a polymer inclusion membrane (PIM) with Aliquat 336 as the carrier for on-line analyte separation and preconcentration. The system operates under flow injection (FI) and continuous flow (CF) conditions. Under optimal FI conditions the system is characterised by a linear concentration range between 0.5 and 1000 μg L{sup −1} P, a sampling rate of 10 h{sup −1}, a limit of detection of 0.5 μg L{sup −1} P and RSDs of 3.2% (n = 10, 100 μg L{sup −1}) and 7.7% (n = 10, 10 μg L{sup −1}). Under CF conditions with 10 min stop-flow time and sample solution flow rate of 1.32 mL min{sup −1} the flow system offers a limit of detection of 0.04 μg L{sup −1} P, a sampling rate of 5 h{sup −1} and an RSD of 3.4% (n = 5, 2.0 μg L{sup −1}). Interference studies revealed that anions commonly found in natural waters did not interfere when in excess of at least one order of magnitude. The flow system, operating under CF conditions, was successfully applied to the analysis of natural water samples containing concentrations of phosphate in the low μg L{sup −1} P range, using the multipoint standard addition method.

TEMPO addition into pre-irradiated fluoropolymers and living-radical graft polymerization of styrene for preparation of polymer electrolyte membranes

Energy Technology Data Exchange (ETDEWEB)

Sawada, Shin-ichi, E-mail: sawada.shinnichi@jaea.go.j [Conducting Polymer Materials Research Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Suzuki, Akihiro; Terai, Takayuki [Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Maekawa, Yasunari, E-mail: maekawa.yasunari@jaea.go.j [Conducting Polymer Materials Research Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

2010-04-15

We prepared proton exchange membranes (PEMs) by 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO)-mediated living-radical graft polymerization (LRGP) of styrene into fluoropolymer films and subsequent sulfonation. Poly(vinylidene fluoride) (PVDF) and poly(ethylene-co-tetrafluoroethylene) (ETFE) films were first irradiated and then treated with TEMPO solutions in various solvents. TEMPO addition was confirmed by the test of styrene grafting into TEMPO-treated films at 60 deg. C, at which the LRGP never proceeds. This test enabled us to differentiate the LRGP from the conventional graft polymerization. In order to gain a deep insight about TEMPO-addition reaction, the TEMPO-penetration behavior into the base polymer films was examined by a permeation experiment and computer simulation. Xylene and dioxane were appropriate solvents for the complete introduction of TEMPO into PVDF and ETFE films, respectively. Then, the LRGP of styrene was performed based on the fully TEMPO-capped films at 125 deg. C with various solvents. By using an alcoholic solvent, the degree of grafting was enhanced and it reached a maximum of 38%. This grafted film was sulfonated to prepare a PEM showing an ion exchange capacity of 2.2 meq/g and proton conductivity of 1.6x10{sup -1} S/cm.

Design of UV-absorbing PVDF membrane via surface-initiated AGET ATRP

Science.gov (United States)

Dong, Li; Liu, Xiangdong; Xiong, Zhengrong; Sheng, Dekun; Zhou, Yan; Lin, Changhong; Yang, Yuming

2018-03-01

Herein, PVDF membranes with excellent UV-absorbing property were first synthesized through grafting the polymerizable low-molecular-weight organic UV-absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) onto α-bromoester-functionalized PVDF membranes via the surface-initiated activator generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The surface initiators were immobilized by the reaction between 2-bromoisobutyryl bromide (BIBB) and the hydroxylated PVDF membranes. PVDF-g-PBPMA membranes with different grafting densities were obtained by tuning the polymerization time and the modified membranes were characterized by 1H-NMR, FT-IR, XPS, SEM, UV-vis Spectrophotometer, TGA and DSC. The experimental results indicated that PBPMA chains were successfully introduced onto PVDF membranes. Most importantly, the PVDF-g-PBPMA membranes exhibited outstanding UV-shielding property. UV-vis transmittance spectra showed that most UV light below 360 nm could be absorbed by PVDF-g-PBPMA membranes and the whole UV light region (200-400 nm) can be blocked with the reaction time increased.

Physical model for membrane protrusions during spreading

International Nuclear Information System (INIS)

Chamaraux, F; Ali, O; Fourcade, B; Keller, S; Bruckert, F

2008-01-01

During cell spreading onto a substrate, the kinetics of the contact area is an observable quantity. This paper is concerned with a physical approach to modeling this process in the case of ameboid motility where the membrane detaches itself from the underlying cytoskeleton at the leading edge. The physical model we propose is based on previous reports which highlight that membrane tension regulates cell spreading. Using a phenomenological feedback loop to mimic stress-dependent biochemistry, we show that the actin polymerization rate can be coupled to the stress which builds up at the margin of the contact area between the cell and the substrate. In the limit of small variation of membrane tension, we show that the actin polymerization rate can be written in a closed form. Our analysis defines characteristic lengths which depend on elastic properties of the membrane–cytoskeleton complex, such as the membrane–cytoskeleton interaction, and on molecular parameters, the rate of actin polymerization. We discuss our model in the case of axi-symmetric and non-axi-symmetric spreading and we compute the characteristic time scales as a function of fundamental elastic constants such as the strength of membrane–cytoskeleton adherence

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

KAUST Repository

Francis, Lijo; Ghaffour, NorEddine; Alsaadi, Ahmad Salem; Amy, Gary L.

2014-01-01

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.

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.

Recent Membrane Development for Pervaporation Processes

KAUST Repository

Ong, Yee Kang

2016-03-11

Pervaporation has been regarded as a promising separation technology in separating azeotropic mixtures, solutions with similar boiling points, thermally sensitive compounds, organic–organic mixtures as well as in removing dilute organics from aqueous solutions. As the pervaporation membrane is one of the crucial factors in determining the overall efficiency of the separation process, this article reviews the research and development (R&D) of polymeric pervaporation membranes from the perspective of membrane fabrication procedures and materials.

Recent Membrane Development for Pervaporation Processes

KAUST Repository

Ong, Yee Kang; Shi, Gui Min; Le, Ngoc Lieu; Tang, Yu Pan; Zuo, Jian; Nunes, Suzana Pereira; Chung, Neal Tai-Shung

2016-01-01

Pervaporation has been regarded as a promising separation technology in separating azeotropic mixtures, solutions with similar boiling points, thermally sensitive compounds, organic–organic mixtures as well as in removing dilute organics from aqueous solutions. As the pervaporation membrane is one of the crucial factors in determining the overall efficiency of the separation process, this article reviews the research and development (R&D) of polymeric pervaporation membranes from the perspective of membrane fabrication procedures and materials.

Polymeric synthetic geo membranes in reservoirs waterproofing in the Kingdom of Morocco; Las geomembranas sinteticas polimericas en la impermeabilizacion de balsas en el Reino de Marruecos

Energy Technology Data Exchange (ETDEWEB)

Blanco Fernandez, M.

2015-07-01

This essay aims to address some of the aspects related to polymeric synthetic geo membranes that could be used in reservoirs of water located in the Kingdom of Morocco. In this regard, it offers a description of the two basic components geo membranes consist of, that is, resins and additives. It also gives an overview of the key pieces of legislation affecting such an issue. Furthermore, it stresses the paramount importance of implementing monitoring procedures in order to assess the condition of geo membranes over time and, if necessary, to proceed to provide for new waterproofing. Lastly, the characteristics of the process monitoring aforementioned are detailed in terms of tensile strength, elongation, tear resistance, dynamic impact, puncture resistance, low-temperature folding. Shore hardness, stress cracking, oxidation induction times, joint strength shear and peeling test, content and dispersion of carbon black and reflection-optical and scanning-electron microscopy. (Author)

Radiolabeling of liposomes and polymeric micelles with PET-isotopes

DEFF Research Database (Denmark)

Jensen, Andreas Tue Ingemann

as a revolution in modern therapeutics, especially in chemotherapy. A major reason is the ability of nanoparticles to accumulate in tumor tissue. Liposomes are the classic nanoparticle, consisting of a lipid membrane with an aqueous core. Polymeric micelles are made from amphiphilic detergent‐like copolymers......This thesis is divided into three separate chapters that can be read independently. Chapter 1 is a general introduction, touching upon liposomes and polymeric micelles and radiolabeling with 18F and 64Cu. Chapter 2 and 3 address two separate research projects, each described below. A complete......‐life only allowing up to 8 hours scans. 18F must be covalently attached to components of the liposome. By binding to a lipid, it can be stably lodged in the membrane. A glycerolipid and a cholesteryl ether were synthesized with free primary alcohols and a series of their sulphonates (Ms, Ts, Tf) were...

Track membranes, production, properties, applications

International Nuclear Information System (INIS)

Oganesjan, Yu.Ts.

1994-01-01

The problems of producing track membranes on heavy ion beams of the Flerov Laboratory are considered. The parameters of the running accelerators and equipment for the irradiation of polymer foils are presented. The process of production of track membranes based on different polymeric materials and various applications of the membranes are described. Special attention is given to the principally new applications and devices developed at the Laboratory. This report presents the results obtained by a big group of scientists and engineers working in the field of elaboration, investigation and application of track membranes (author). 21 refs, 20 figs, 1 tab

In-line coupling of microextractions across polymer inclusion membranes to capillary zone electrophoresis for rapid determination of formate in blood samples

Czech Academy of Sciences Publication Activity Database

Pantůčková, Pavla; Kubáň, Pavel; Boček, Petr

2015-01-01

Roč. 887, AUG (2015), s. 111-117 ISSN 0003-2670 R&D Projects: GA ČR(CZ) GA13-05762S Grant - others:GA AV ČR(CZ) R200311404 Institutional support: RVO:68081715 Keywords : capillary electrophoresis * in-line coupling * polymer inclusion membrane extraction Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.712, year: 2015

Morin-based nanofiltration membranes for organic solvent separation processes

KAUST Repository

Perez Manriquez, Liliana

2018-02-26

In this work we demonstrate the successful optimization of the interfacial polymerization reaction for the manufacture of organic solvent nanofiltration membranes by replacing the toxic amines commonly used for this method with the natural occurring bio-polyphenol morin. For the manufacture of this type of OSN membrane a crosslinked PAN support was coated by interfacial polymerization using morin as the monomer of the aqueous phase and terephtaloyl chloride as the monomer of the organic phase. These membranes showed an exceptional performance and resistance to NMP by having a a permeance of 0.3L/m2 h bar in NMP with a rejection of 96% of Brilliant Blue dye which has a molecular weight of 825.97g/mol, making these membranes attractive for harsh industrial separation processes due to their ease of manufacture, low cost, and excellent performance.

Thin-film composite crosslinked polythiosemicarbazide membranes for organic solvent nanofiltration (OSN)

KAUST Repository

Aburabie, Jamaliah

2015-01-01

In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes reported up to now. Integrally skinned asymmetric PTSC membranes were prepared by the phase inversion process and crosslinked with an aromatic bifunctional crosslinker to improve the solvent stability. TFC membranes were obtained via interfacial polymerization using trimesoyl chloride (TMC) and diaminopiperazine (DAP) monomers. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement.The membranes exhibited high fluxes toward solvents like tetrahydrofuran (THF), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) ranging around 20L/m2 h at 5bar with a molecular weight cut off (MWCO) of around 1000g/mol. The PTSC-based thin-film composite membranes are very stable toward polar aprotic solvents and they have potential applications in the petrochemical and pharmaceutical industry.

A novel membrane-bound toxin for cell division, CptA (YgfX), inhibits polymerization of cytoskeleton proteins, FtsZ and MreB, in Escherichia coli.

Science.gov (United States)

Masuda, Hisako; Tan, Qian; Awano, Naoki; Yamaguchi, Yoshihiro; Inouye, Masayori

2012-03-01

Nearly all free-living bacteria carry toxin-antitoxin (TA) systems on their genomes, through which cell growth and death are regulated. Toxins target a variety of essential cellular functions, including DNA replication, translation, and cell division. Here, we identified a novel toxin, YgfX, on the Escherichia coli genome. The toxin, consisting of 135 residues, is composed of the N-terminal membrane domain, which encompasses two transmembrane segments, and the C-terminal cytoplasmic domain. Upon YgfX expression, the cells were initially elongated and then the middle portion of the cells became inflated to form a lemon shape. YgfX was found to interact with MreB and FtsZ, two essential cytoskeletal proteins in E. coli. The cytoplasmic domain [YgfX(C)] was found to be responsible for the YgfX toxicity, as purified YgfX(C) was found to block the polymerization of FtsZ and MreB in vitro. YgfY, located immediately upstream of YgfX, was shown to be the cognate antitoxin; notably, YgfX is the first membrane-associating toxin in bacterial TA systems. We propose to rename the toxin and the antitoxin as CptA and CptB (for Cytoskeleton Polymerization inhibiting Toxin), respectively. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Polyethersulfone/clay membranes and its water permeability; Membranas de polietersulfona/argila e sua permeabilidade a agua

Energy Technology Data Exchange (ETDEWEB)

Cavalho, Thamyres Cardoso de; Medeiros, Vanessa da Nobrega; Araujo, Edcleide Maria de; Lira, Helio Lucena, E-mail: thamyrescc@gmail.com, E-mail: vanismedeiros@gmail.com, E-mail: edcleide.araujo@ufcg.edu.br, E-mail: helio.lira@ufcg.edu.br [Universidade Federal de Campina Grande (UAEMa/CCT/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Leite, Amanda Melissa Damiao, E-mail: amanda.leite@ect.ufrn.br [Universidade Federal do Rio Grande do Norte (ECT/UFRN), Natal, RN (Brazil). Escola de Ciencia e Tecnologia

2017-04-15

Membranes can be considered polymeric or inorganic films that function as a semipermeable barrier to filtration on a molecular scale, separating two phases and restricting, totally or partially, the transportation of one or more chemical species (solute) present in the solution. Therefore, the aim of this work is to produce polyethersulfone membranes (PES) and polyethersulfone/clay by phase inversion technique and evaluate the presence of clay in obtaining membranes for wastewater treatment. The used solvent was dimethylformamide (DMF) and clays were Brasgel PA (MMT) and Cloisite Na (CL Na) in the proportion of 3 to 5% (wt.). By Xray diffraction (XRD), the membranes with 3% of MMT and CL Na clays apparently had partially exfoliated structures. For the composition with 5% of CL Na a small peak was observed, which indicates that this is possibly an intercalated structure or microcomposite. By scanning electron microscopy (SEM), visualizes that the pure surface of the pure PES membrane a structure apparently without pores was observed in the used magnification and without roughness surface when compared to membranes with clay. The measurements of contact angle indicated that the inclusion of clay altered the wetting ability of the membranes. The flow with distilled water for all membranes started high and over time reached a stabilization level. Thus, it can be concluded that the presence and the content of clay altered the morphology of the membrane, contributing to an increase in water flow. (author)

Mixed-linker zeolitic imidazolate framework mixed-matrix membranes for aggressive CO2 separation from natural gas

KAUST Repository

Thompson, Joshua A.

2014-07-01

Zeolitic imidazolate framework (ZIF) materials are a promising subclass of metal-organic frameworks (MOF) for gas separations. However, due to the deleterious effects of gate-opening phenomena associated with organic linker rotation near the limiting pore apertures of ZIFs, there have been few demonstrations of improved gas separation properties over pure polymer membranes when utilizing ZIF materials in composite membranes for CO2-based gas separations. Here, we report a study of composite ZIF/polymer membranes, containing mixed-linker ZIF materials with ZIF-8 crystal topologies but composed of different organic linker compositions. Characterization of the mixed-linker ZIFs shows that the mixed linker approach offers control over the porosity and pore size distribution of the materials, as determined from nitrogen physisorption and Horváth-Kawazoe analysis. Single gas permeation measurements on mixed-matrix membranes reveal that inclusion of mixed-linker ZIFs yields membranes with better ideal CO2/CH4 selectivity than membranes containing ZIF-8. This improvement is shown to likely occur from enhancement in the diffusion selectivity of the membranes associated with controlling the pore size distribution of the ZIF filler. Mixed-gas permeation experiments show that membranes with mixed-linker ZIFs display an effective plasticization resistance that is not typical of the pure polymeric matrix. Overall, we demonstrate that mixed-linker ZIFs can improve the gas separation properties in composite membranes and may be applicable to aggressive CO2 concentrations in natural gas feeds. © 2013 Elsevier Inc. All rights reserved.

Broad spectrum antibacterial and antifungal polymeric paint materials: synthesis, structure-activity relationship, and membrane-active mode of action.

Science.gov (United States)

Hoque, Jiaul; Akkapeddi, Padma; Yadav, Vikas; Manjunath, Goutham B; Uppu, Divakara S S M; Konai, Mohini M; Yarlagadda, Venkateswarlu; Sanyal, Kaustuv; Haldar, Jayanta

2015-01-28

Microbial attachment and subsequent colonization onto surfaces lead to the spread of deadly community-acquired and hospital-acquired (nosocomial) infections. Noncovalent immobilization of water insoluble and organo-soluble cationic polymers onto a surface is a facile approach to prevent microbial contamination. In the present study, we described the synthesis of water insoluble and organo-soluble polymeric materials and demonstrated their structure-activity relationship against various human pathogenic bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and beta lactam-resistant Klebsiella pneumoniae as well as pathogenic fungi such as Candida spp. and Cryptococcus spp. The polymer coated surfaces completely inactivated both bacteria and fungi upon contact (5 log reduction with respect to control). Linear polymers were more active and found to have a higher killing rate than the branched polymers. The polymer coated surfaces also exhibited significant activity in various complex mammalian fluids such as serum, plasma, and blood and showed negligible hemolysis at an amount much higher than minimum inhibitory amounts (MIAs). These polymers were found to have excellent compatibility with other medically relevant polymers (polylactic acid, PLA) and commercial paint. The cationic hydrophobic polymer coatings disrupted the lipid membrane of both bacteria and fungi and thus showed a membrane-active mode of action. Further, bacteria did not develop resistance against these membrane-active polymers in sharp contrast to conventional antibiotics and lipopeptides, thus the polymers hold great promise to be used as coating materials for developing permanent antimicrobial paint.

The oxidation of PET track-etched membranes by hydrogen peroxide as an effective method to increase efficiency of UV-induced graft polymerization

Directory of Open Access Journals (Sweden)

Il'ya Korolkov

2015-12-01

Full Text Available In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate (PET TeMs oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid (PAA chains inside the membrane nanochannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

Polymeric membranes containing silver salts for propylene/propane separation

Directory of Open Access Journals (Sweden)

L. D. Pollo

2012-06-01

Full Text Available The separation of olefin/paraffin mixtures is one of the most important processes of the chemical industry. This separation is typically carried out by distillation, which is an energy and capital intensive process. One promising alternative is the use of facilitated transport membranes, which contain specific carrier agents in the polymer matrix that interact reversibly with the double bond in the olefin molecule, promoting the simultaneous increase of its permeability and selectivity. In this study, polyurethane (PU membranes were prepared using two different silver salts (triflate and hexafluorantimonate. The membranes were structurally characterized and their performance for the separation of propylene/propane mixtures was evaluated. The results of the characterization analyses indicated that the triflate salt was the most efficient carrier agent. The membranes containing this salt showed the best performance, reaching an ideal selectivity of 10 and propylene permeability of 188 Barrer.

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.

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.; Koros, William J.

2009-01-01

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.

Activation of PVDF membranes through facile hydroxylation of the polymeric dope

KAUST Repository

Al-Gharabli, Samer; Mavukkandy, Musthafa O.; Kujawa, Joanna; Nunes, Suzana Pereira; Arafat, Hassan A.

2017-01-01

A method comprising a two-step alkali/acid treatment of poly (vinylidene fluoride) (PVDF) polymer is developed for the fabrication of flat-sheet PVDF membranes functionalized with labile hydroxyl groups. This method involves the application of a short-duration modification in alkali medium (5% KOH). Extensive characterizations were performed on the prepared membranes. Modification of the polymer altered the crystallinity of the PVDF from a mixture of both α and β phases to a predominant β phase. Lower work of adhesion of the modified membrane indicated the formation of a more hydrophobic and wetting-resistant membrane surface. Centrifugation of the polymer dope after the modification had a pronounced impact on the properties of the resultant membranes. This protocol could be utilized in fine-tuning the properties of PVDF membranes for various target-specific applications such as membrane distillation. This method can also be used in functionalizing PVDF membranes further by exploiting the labile –OH group present on the membrane surface.

Activation of PVDF membranes through facile hydroxylation of the polymeric dope

KAUST Repository

Al-Gharabli, Samer

2017-10-30

A method comprising a two-step alkali/acid treatment of poly (vinylidene fluoride) (PVDF) polymer is developed for the fabrication of flat-sheet PVDF membranes functionalized with labile hydroxyl groups. This method involves the application of a short-duration modification in alkali medium (5% KOH). Extensive characterizations were performed on the prepared membranes. Modification of the polymer altered the crystallinity of the PVDF from a mixture of both α and β phases to a predominant β phase. Lower work of adhesion of the modified membrane indicated the formation of a more hydrophobic and wetting-resistant membrane surface. Centrifugation of the polymer dope after the modification had a pronounced impact on the properties of the resultant membranes. This protocol could be utilized in fine-tuning the properties of PVDF membranes for various target-specific applications such as membrane distillation. This method can also be used in functionalizing PVDF membranes further by exploiting the labile –OH group present on the membrane surface.

Study on non-ionic membrane prepared by radiation-induced graft polymerization

International Nuclear Information System (INIS)

Hegazy, E.-S.A.; Mokhtar, S.M.; Osman, M.B.S.; Mostafa, A.E.-K.B.

1990-01-01

The preparation of good hydrogel supported on polymeric material was carried out by means of direct radiation-induced graft polymerization of N-vinyl-2-pyrrolidone (NVP) onto low density polyethylene films (LDPE). The optimum conditions were determined, at which the grafting process occurred and suitable degrees of grafting were obtained with a homogeneous distribution of the graft chains throughout the polymer. The effect of different inhibitors, addition of ZnCl 2 and monomer concentration on the grafting yield was also studied. Some investigations and characterization on the prepared graft copolymer were investigated and the possibility of its practical use was discussed. Mechanical properties, thermal and chemical stability and hydrophilic properties of such prepared grafted films showed a great promise in some practical applications. (author)

Liquid radioactive wastes from hospitals by polymeric membrane

International Nuclear Information System (INIS)

Arnal, J.M.; Sancho, M.; Verdu, G.; Campayo, J.M.

1998-01-01

Streams containing I''125 produced from RIA process, classified as radioactive waste of low activity, are generated by all different treatments applied in IN VITRO techniques. Consequently, an accumulation of solutions containing I''125 is produced in the order of 50-100 L/month approximately. The storage at sanitary centres and the accumulation caused by it creates a serious problem in the hospital. According to the specific activity and the installation spill authorization, one can choose between three ways of handling: direct discharge, temporal storage until the radioactive waste come to decay and then discharged, waste management by the authorised company (ENRESA). If the third way of discharge is applied the treatment of waste using membranes should be considered. Using membranes, important reduction coefficients in volume in the order of 10:1 are obtained. The aim of this work is the declassification of the I''125 solutions as a liquid radioactive waste using membrane techniques. Both, a radioactive concentrated waste and non-contaminated waste are obtained. (Author)

Cross-linked polymeric membranes for carbon dioxide separation

Science.gov (United States)

Hong, Tao; Chatterjee, Sabornie; Mahurin, Shannon Mark; Long, Brian Keith; Jiang, De-en; Mays, Jimmy Wayne; Sokolov, Alexei P.; Saito, Tomonori

2018-01-23

A membrane useful in gas separation, the membrane comprising a cross-linked polysiloxane structure having a cross-link density of about 0.1.times.10.sup.-5 mol/cm.sup.3 to about 6.times.10.sup.-5 mol/cm.sup.3, where, in particular embodiments, the cross-linked polysiloxane structure has the following general structure: ##STR00001## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently selected from hydrocarbon groups having at least 1 and up to 6 carbon atoms; A.sup.1 and A.sup.2 are independently selected from cyclic hydrocarbon groups; L.sup.1 and L.sup.2 are linking groups or covalent bonds; n is an integer of at least 1; r and s are independently selected from integers of at least 1; and p is an integer of at least 10. The invention also includes methods for making and using the above-described membranes for gas separation.

Chitosan/Carboxymethylcellulose/Ionic Liquid/Ag(0) Nanoparticles Form a Membrane with Antimicrobial Activity

International Nuclear Information System (INIS)

Quadros, C.; Faria, V.W.; Scheeren, C.W.; Klein, M.P.; Hertz, P.F.

2013-01-01

Silver metal nanoparticles were immobilized in chitosan/carboxymethylcellulose/BMI.BF4(1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid) (CS/CMC/IL) to form polymeric membrane with 20 μm thickness. The CS/CMC/IL polymeric membrane was prepared using a simple solution blending method. Irregularly shaped Ag(0) nanoparticles with monomodal size distributions of nm Ag(0) were immobilized in the membrane. The presence of small Ag(0) nanoparticles induced an augmentation in the CS/CMC/IL film surface areas. The CS/CMC/IL membrane containing Ag(0) showed increase antimicrobial activity the Ag(0) concentration increased up to saturation at 10 mg. CS/CMC/IL membrane that contains Ag(0) nanoparticles has enhanced durability of the membrane and exhibited stronger antimicrobial activity against Escherichia coli and Staphylococcus aureus.

Polymeric microsieves via phase separation microfabrication: Process and design optimization

NARCIS (Netherlands)

Bikel, M.; Culfaz, P.Z.; Bolhuis-Versteeg, Lydia A.M.; Perez, J. Garduno; Lammertink, Rob G.H.; Wessling, Matthias

2010-01-01

Phase separation microfabrication (PSμF) is a fabrication method that allows the preparation of membranes having micropattern surface topologies. PSμF has been successfully used for manufacturing polymeric microsieves. The technique benefits from the vertical shrinkage of polymer solutions to ensure

Atomic Force Microscopy as a Tool for Asymmetric Polymeric Membrane Characterization

International Nuclear Information System (INIS)

Abdul Wahab Mohammad; Pei, L.Y.; Indok Nurul Hasyimah Mohd Amin; Rafeqah Raslan

2011-01-01

Atomic force microscopy (AFM) has a wide range of applications and is rapidly growing in research and development. This powerful technique has been used to visualize surfaces both in liquid or gas media. It has been considered as an effective tool to investigate the surface structure for its ability to generate high-resolution 3D images at a subnanometer range without sample pretreatment. In this paper, the use of AFM to characterize the membrane roughness is presented for commercial and self-prepared membranes for specific applications. Surface roughness has been regarded as one of the most important surface properties, and has significant effect in membrane permeability and fouling behaviour. Several scan areas were used to compare surface roughness for different membrane samples. Characterization of the surfaces was achieved by measuring the average roughness (R a ) and root mean square roughness (R rms ) of the membrane. AFM image shows that the membrane surface was composed entirely of peaks and valleys. Surface roughness is substantially greater for commercial available hydrophobic membranes, in contrast to self-prepared membranes. This study also shows that foulants deposited on membrane surface would increase the membrane roughness. (author)

Direct quantification of negatively charged functional groups on membrane surfaces

KAUST Repository

Tiraferri, Alberto; Elimelech, Menachem

2012-01-01

groups at the surface of dense polymeric membranes. Both techniques consist of associating the membrane surface moieties with chemical probes, followed by quantification of the bound probes. Uranyl acetate and toluidine blue O dye, which interact

Mixed Matrix Composite Membranes Containing POSS Molecules for Carbon Dioxide Removal Application

KAUST Repository

Rini, Eki Listya

2011-05-10

CO2 removal by membrane processes is considerably potential for several applications such as natural gas and synthesis gas purification, enhanced oil recovery application, and carbon dioxide capture in combat against global warming. Dense polymeric membranes are commonly utilized for these type of gas separation applications. Nevertheless, the intrinsic properties of dense polymeric membranes, which commonly characterize by the low gas permeability versus high gas selectivity trade–off or vice versa, is less desirable. In order to meet the increased demand of CO2 removal, a strategy to improve the gas separation performance of a polymeric membrane is investigated in this study. With this regard, mixed matrix membranes in which inorganic non porous fillers are incorporated into a polymeric matrix were prepared to achieve the aforementioned objective. The mixed matrix membranes were prepared from Pebax® block copolymers and PEG POSS® molecules. These hybrid membranes were formed as both dense and multilayer composite membranes. The dense transparent membranes with well–dispersed fillers could be obtained by variation of the solvent mixture. The DSC analyses showed that incorporation of PEG POSS® into Pebax® matrix altered the thermal properties of the matrix. The multilayer composite membranes were then prepared from a PTMSP gutter layer deposited on a PAN porous support and an adjacent hybrid Pebax®/PEG POSS® as the top layer. These hybrid multilayer composite membranes exhibited an enhanced CO2 selectiv4 ity by a factor of two relative to the pure Pebax®. In these hybrid systems, the CO2 separation was presumably enhanced by the high ether oxides content from PEG POSS® that has high affinities for CO2. For particular composition of Pebax® and PEG POSS® concentrations, the PTMSP gutter layer harnessed the CO2 selectivity without losing the CO2 permeation rate. At the same time, these membrane, however, suffered severe adhesion between the gutter layer

Factors Influencing Membrane fouling in the MBR Process

Directory of Open Access Journals (Sweden)

Parvin Nahid

2018-01-01

Full Text Available Biological processes of wastewater treatmnent have found wide applications due to their lower costs and higher efficiency. Membrane bioreactors (MBR’s form one group of such processes in which membrane fouling is of great importance. Efficiency of critical flux (CF has been proved to be a parameter effective in fouling control (CF. CF is itself influenced by three main groups of variables that include sludge parameters, operating conditions, and membrane types. In this stidy, the effects of such factors as trans-membrane pressure, protein and carbohydrate concentrations in extracellular polymeric substances (EPS, and soluble microbial products (SMP on CF were investigated in a submerged MBR.  Moreover, the effects of such operating conditions as periodic and continuous suctions at two sludge concentrations were studied. It was found that increasing flux led to enhanced membrane fouling rates. Extracellular polymeric substances (EPS were found to have no relations with critical flux (CF, probably because EPS are mostly found as bigger flocks. Finally, a reverse relationship was established between CF and carbohydrate concentration of the SMP. Membrane fouling control was observed to be positively affected by the rest modes during periodic suctions.

Axonal inclusions in the crab Hemigrapsus nudus.

Science.gov (United States)

Smith, R S

1978-10-01

Light microscopic examination of living giant axons from the walking legs of Hemigrapsus nudus revealed intra-axonal inclusions which were usually several tens of micrometers long and about 5 micron wide. The inclusions were filled with small light-scattering particles. The inclusions were shown, by thin section electron microscopy, to be composed largely 68% by volume) of mitochondria. Each inclusion was surrounded by membrane bounded spaces which are presumed to represent a part of the smooth endoplasmic reticulum. Similar inclusions were not found in the leg axons of a variety of other decapod crustaceans.

Membrane modules for building ventilation

Energy Technology Data Exchange (ETDEWEB)

Kistler, K.R.; Cussler, E.L.

2002-01-01

Hollow fibre and flat sheet membranes with an interfacially polymerized coating of polyamide have a permeance for water vapour of about 0.16 m sec{sup -1}. These membranes can serve as a basis for building ventilation which provides fresh air while recovering about 70% of the specific heat and 60% of the latent heat. Because these membranes are selective for water vapour, the air is exhausted with internal pollutants like carbon monoxide, formaldehyde, and radon. The expense of the ventilator should be recovered in reduced heating costs in about three years. (Author)

Transport through track etched polymeric blend membrane

Indian Academy of Sciences (India)

Unknown

Department of Physics, University of Rajasthan, Jaipur 302 004, India. MS received 10 June 2005 ... Both the track and bulk etching takes place in the irradiated membrane. ... using rotating flywheel attachment, the details having been given ...

Towards supported bolaamphiphile membranes for water filtration: Roles of lipid and substrate

NARCIS (Netherlands)

Kaufman, Y.; Grinberg, S.; Linder, C..; Heldman, E.; Gilron, J.; Shen, Yue-xiao; Kumar, M.; Lammertink, Rob G.H.; Freger, V.

2014-01-01

Supported biomimetic membranes hold potential for applications such as biosensors and water purification by filtration. The current paper reports on the preparation of a supported bolaamphiphile membrane on two polymeric nanofiltration membranes: NF-270 made of polyamide with carboxylic surface

Retention measurements of nanofiltration membranes with electrolyte solutions

NARCIS (Netherlands)

Peeters, J.M.M.; Peeters, J.M.M.; Boom, J.P.; Boom, J.P.; Mulder, M.H.V.; Strathmann, H.

1998-01-01

Retention measurements with single salt solutions of CaCl2, NaCl and Na2SO4 revealed that the rejection mechanism of commercial polymeric nanofiltration membranes investigated in this study may be divided into two categories: 1. Membranes for which Donnan exclusion seems to play an important role.

Nanostructured Polysulfone-Based Block Copolymer Membranes

KAUST Repository

Xie, Yihui

2016-05-01

The aim of this work is to fabricate nanostructured membranes from polysulfone-based block copolymers through self-assembly and non-solvent induced phase separation. Block copolymers containing polysulfone are novel materials for this purpose providing better mechanical and thermal stability to membranes than polystyrene-based copolymers, which have been exclusively used now. Firstly, we synthesized a triblock copolymer, poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) through polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids. Membrane surface hydrolysis was carried out in a combination with metal complexation to obtain metal-chelated membranes. The copper-containing membrane showed improved antibacterial capability. Secondly, a poly(acrylic acid)-b-polysulfone-b-poly(acrylic acid) triblock copolymer obtained by hydrolyzing poly(tert-butyl acrylate)-b-polsulfone-b-poly(tert-butyl acrylate) formed a thin film with cylindrical poly(acrylic acid) microdomains in polysulfone matrix through thermal annealing. A phase inversion membrane was prepared from the same polymer via self-assembly and chelation-assisted non-solvent induced phase separation. The spherical micelles pre-formed in a selective solvent mixture packed into an ordered lattice in aid of metal-poly(acrylic acid) complexation. The space between micelles was filled with poly(acrylic acid)-metal complexes acting as potential water channels. The silver0 nanoparticle-decorated membrane was obtained by surface reduction, having three distinct layers with different particle sizes. Other amphiphilic copolymers containing polysulfone and water-soluble segments such as poly(ethylene glycol) and poly(N-isopropylacrylamide) were also synthesized through coupling reaction and copper0-mediated

Partially fluorinated electrospun proton exchange membranes

DEFF Research Database (Denmark)

2016-01-01

The present invention relates to a novel porous membrane layer, to a novel method for producing a membrane, and the membranes produced by the novel method. The present invention further relates to a fuel cell comprising the porous layer, as well as any use of the porous layer in a fuel cell or in...... copolymer, and wherein at least one side chain of the graft copolymer comprises a polymerization product of a polymerizable proton donor group or a precursor thereof....

A Novel Seeding Method of Interfacial Polymerization-Assisted Dip Coating for the Preparation of Zeolite NaA Membranes on Ceramic Hollow Fiber Supports.

Science.gov (United States)

Cao, Yue; Wang, Ming; Xu, Zhen-Liang; Ma, Xiao-Hua; Xue, Shuang-Mei

2016-09-28

A novel seeding method combining interfacial polymerization (IP) technique with dip-coating operation was designed for directly coating nanosized NaA seed crystals (150 nm) onto the micrometer-sized α-Al2O3 hollow fiber support, in which the polyamide (PA) produced by IP acted as an effective medium to freeze and fix seed crystals at the proper position so that the controlled seed layer could be accomplished. While a coating suspension with only 0.5 wt % seed content was used, a very thin seed layer with high quality and good adhesion was achieved through dip coating twice without drying between, and the whole seeding process was operated at ambient conditions. The resulting zeolite NaA membranes not only exhibited high pervaporation (PV) performance with an average separation factor above 10000 and flux nearly 9.0 kg/m(2)·h in dehydration of 90 wt % ethanol aqueous solution at 348 K but also demonstrated great reproducibility by testing more than eight batches of zeolite membranes. In addition, this seeding strategy could be readily extended to the preparation of other supported zeolite membranes for a wide range of separation applications.

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

Energy Technology Data Exchange (ETDEWEB)

Li Jianhua, E-mail: jhli_2005@163.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Zhang Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China) and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, Tianjin 300192 (China)

2012-06-15

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

International Nuclear Information System (INIS)

Li Jianhua; Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng; Zhang Qiqing

2012-01-01

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

MECHANISM OF LIQUID MEMBRANES AND APPLICATIONS

Directory of Open Access Journals (Sweden)

Filiz Nuran ACAR

2002-02-01

Full Text Available It has been considerably studied on the recycling of waste materials in the source besides of wastewater treatment in the last years. It has been important developments on the using of semiconductor membranes in the recycling of toxic materials such as heavy metals, intensifying the environment protection measures especially in the west countries. Wastewater treatment has been achieved with liquid membranes as it has been achieved with polymeric membrane systems such as ultrafiltration, microfiltration, electrodialysis. At the same time, liquid membranes are used for removal of metal ions in hydrometallurgy. Liquid membranes are also used in biotechnology, medical areas and gas separation process.

Polymer-metal organic frameworks (MOFs) mixed matrix membranes for gas separation applications

NARCIS (Netherlands)

Shahid, S.

2015-01-01

The performance of polymeric membranes is often limited by a trade-off between membrane permeability and selectivity, the so-called Robeson upper bound. Additionally, in high pressure CO2 capture applications, excessive swelling of the polymer membrane often leads to plasticization resulting in

Aluminum uptake from natural waters by a radiation-grafted membrane

Energy Technology Data Exchange (ETDEWEB)

Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C., E-mail: ageraldo@ipen.br, E-mail: ryamaguishi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

Aluminum uptake from natural waters by a radiation-grafted membrane

International Nuclear Information System (INIS)

Bazante-Yamaguishi, Renata; Moura, Eduardo; Manzoli, Jose E.; Geraldo, Aurea B.C.

2013-01-01

Styrene grafted, chemically modified polymeric membranes were used to carry off aluminum of drinking water from wells located at Billings dam region. The membranes comprised polymeric substrates of PVC (polyvinylchloride) and PP (polypropylene), which were mutually grafted with gamma radiation. The chemical modification included three basic reaction paths: Friedel-Crafts acylation, 2-methylanisole coupling and a final oxidation; this modification enables aluminum selectivity on the membrane. This chemical process inserts a salicylated derivative bonded onto the aromatic ring of styrene; such molecular arrangement is responsible for complexation of aluminum ions. The aluminum sorption capacity of these membranes was evaluated firstly from an aluminum control solution, where parameters like the ideal pH value for aluminum sorption and the interfering species were studied and correlated to know the best conditions for aluminum uptake. Later, the membranes were used for aluminum remediation of natural waters (real-life samples). The applicability results and limits are then discussed. (author)

Thin-film composite crosslinked polythiosemicarbazide membranes for organic solvent nanofiltration (OSN)

KAUST Repository

Aburabie, Jamaliah; Neelakanda, Pradeep; Karunakaran, Madhavan; Peinemann, Klaus-Viktor

2015-01-01

In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes

Plasma-chemical modification of the structure and properties of poly(ethylene terephthalate) track membranes

International Nuclear Information System (INIS)

Kravets, L I; Dmitriev, S N; Dinescu, G; Lazea, A; Sleptsov, V V; Elinson, V M

2007-01-01

A process of extraction of the low-molecular products of the synthesis from the poly(ethylene terephthalate) track membranes modified by plasma has been investigated. It is shown that the deposition of a thin polymeric hydrocarbon film by cyclohexane plasma on the membrane surface with preliminary treatment in a plasma of non-polymerizing gases, for example oxygen, allows one to produce membranes possessing a high productivity. Their advantages are much better hydrodynamic properties and a small amount of the low-molecular products of the synthesis extracted by organic solvents

Detecting Levels of Polyquaternium-10 (PQ-10) via Potentiometric Titration with Dextran Sulphate and Monitoring the Equivalence Point with a Polymeric Membrane-Based Polyion Sensor.

Science.gov (United States)

Ferguson, Stephen A; Wang, Xuewei; Meyerhoff, Mark E

2016-08-07

Polymeric quaternary ammonium salts (polyquaterniums) have found increasing use in industrial and cosmetic applications in recent years. More specifically, polyquaternium-10 (PQ-10) is routinely used in cosmetic applications as a conditioner in personal care product formulations. Herein, we demonstrate the use of potentiometric polyion-sensitive polymeric membrane-based electrodes to quantify PQ-10 levels. Mixtures containing both PQ-10 and sodium lauryl sulfate (SLS) are used as model samples to illustrate this new method. SLS is often present in cosmetic samples that contain PQ-10 (e.g., shampoos, etc.) and this surfactant species interferes with the polyion sensor detection chemistry. However, it is shown here that SLS can be readily separated from the PQ-10/SLS mixture by use of an anion-exchange resin and that the PQ-10 can then be titrated with dextran sulphate (DS). This titration is monitored by potentiometric polyanion sensors to provide equivalence points that are directly proportional to PQ-10 concentrations.

Monitoring Protein Fouling on Polymeric Membranes Using Ultrasonic Frequency-Domain Reflectometry

Directory of Open Access Journals (Sweden)

Robin Fong

2011-08-01

Full Text Available Novel signal-processing protocols were used to extend the in situ sensitivity of ultrasonic frequency-domain reflectometry (UFDR for real-time monitoring of microfiltration (MF membrane fouling during protein purification. Different commercial membrane materials, with a nominal pore size of 0.2 µm, were challenged using bovine serum albumin (BSA and amylase as model proteins. Fouling induced by these proteins was observed in flat-sheet membrane filtration cells operating in a laminar cross-flow regime. The detection of membrane-associated proteins using UFDR was determined by applying rigorous statistical methodology to reflection spectra of ultrasonic signals obtained during membrane fouling. Data suggest that the total power reflected from membrane surfaces changes in response to protein fouling at concentrations as low as 14 μg/cm2, and results indicate that ultrasonic spectra can be leveraged to detect and monitor protein fouling on commercial MF membranes.

Hybrid inorganic-organic membranes: Tuning pore properties by sequential grafting

NARCIS (Netherlands)

Sripathi, V.G.P.

2014-01-01

In this thesis, the synthesis of inorganic - polymeric hybrid membranes by sequential grafting is discussed, for application in gas separation. At high pressures and temperatures, organic (olymer) membranes may suffer from swelling and plasticization. Generally, this causes a reduced molecular

Achievements of European projects on membrane reactor for hydrogen production

NARCIS (Netherlands)

di Marcoberardino, G.; Binotti, M.; Manzolini, G.; Viviente, J.L.; Arratibel Plazaola, A.; Roses, L.; Gallucci, F.

2017-01-01

Membrane reactors for hydrogen production can increase both the hydrogen production efficiency at small scale and the electric efficiency in micro-cogeneration systems when coupled with Polymeric Electrolyte Membrane fuel cells. This paper discusses the achievements of three European projects

Metamaterial membranes

International Nuclear Information System (INIS)

Restrepo-Flórez, Juan Manuel; Maldovan, Martin

2017-01-01

We introduce a new class of metamaterial device to achieve separation of compounds by using coordinate transformations and metamaterial theory. By rationally designing the spatial anisotropy for mass diffusion, we simultaneously concentrate different compounds in different spatial locations, leading to separation of mixtures across a metamaterial membrane. The separation of mixtures into their constituent compounds is critically important in biophysics, biomedical, and chemical applications. We present a practical case where a mixture of oxygen and nitrogen diffusing through a polymeric planar matrix is separated. This work opens doors to new paradigms in membrane separations via coordinate transformations and metamaterials by introducing novel properties and unconventional mass diffusion phenomena. (paper)

Composite perfluorohydrocarbon membranes, their preparation and use

Energy Technology Data Exchange (ETDEWEB)

Ding, Yong; Bikson, Benjamin

2017-04-04

Composite porous hydrophobic membranes are prepared by forming a perfluorohydrocarbon layer on the surface of a preformed porous polymeric substrate. The substrate can be formed from poly (aryl ether ketone) and a perfluorohydrocarbon layer can be chemically grafted to the surface of the substrate. The membranes can be utilized for a broad range of fluid separations, such as microfiltration, nanofiltration, ultrafiltration as membrane contactors for membrane distillation and for degassing and dewatering of fluids. The membranes can further contain a dense ultra-thin perfluorohydrocarbon layer superimposed on the porous poly (aryl ether ketone) substrate and can be utilized as membrane contactors or as gas separation. membranes for natural gas treatment and gas dehydration.

Method of Making Reaction Induced Phase Separation Membranes and Uses Thereof

KAUST Repository

Peinemann, Klaus-Viktor

2017-08-10

Provided herein are methods of making asymmetric membranes comprising a first layer and a second layer. The methods include preparing a polymeric solution comprising one or more polymers, casting the polymeric solution to form a polymeric film, contacting the polymeric film with a solvent comprising a crosslinker under conditions to form a first layer on the top of the film, wherein the first layer is dense and solvent resistant, and contacting the polymeric film having the dense, solvent-resistant first layer with a non-solvent solution under conditions that form a porous second layer on the bottom of the film.

Nanostructured Polysulfone-Based Block Copolymer Membranes

KAUST Repository

Xie, Yihui

2016-01-01

polycondensation and reversible addition-fragmentation chain-transfer polymerization. The obtained membrane has a highly porous interconnected skin layer composed of elongated micelles with a flower-like arrangement, on top of the graded finger-like macrovoids

Membrane properties for permeability testing: Skin versus synthetic membranes.

Science.gov (United States)

Haq, Anika; Dorrani, Mania; Goodyear, Benjamin; Joshi, Vivek; Michniak-Kohn, Bozena

2018-03-25

Synthetic membranes that are utilized in diffusion studies for topical and transdermal formulations are usually porous thin polymeric sheets for example cellulose acetate (CA) and polysulfones. In this study, the permeability of human skin was compared using two synthetic membranes: cellulose acetate and Strat-M® membrane and lipophilic and hydrophilic compounds either as saturated or formulated solutions as well as marketed dosage forms. Our data suggests that hydrophilic compounds have higher permeation in Strat-M membranes compared with lipophilic ones. High variation in permeability values, a typical property of biological membranes, was not observed with Strat-M. In addition, the permeability of Strat-M was closer to that of human skin than that of cellulose acetate (CA > Strat-M > Human skin). Our results suggest that Strat-M with little or no lot to lot variability can be applied in pilot studies of diffusion tests instead of human skin and is a better substitute than a cellulose acetate. Copyright © 2018 Elsevier B.V. All rights reserved.

Formation of carrageenan-CaCO{sub 3} bioactive membranes

Energy Technology Data Exchange (ETDEWEB)

Nogueira, Lucas F.B.; Maniglia, Bianca C.; Pereira, Lourivaldo S.; Tapia-Blácido, Delia R.; Ramos, Ana P., E-mail: anapr@ffclrp.usp.br

2016-01-01

The high biocompatibility and resorbability of polymeric membranes have encouraged their use to manufacture medical devices. Here, we report on the preparation of membranes consisting of carrageenan, a naturally occurring sulfated polysaccharide that forms helical structures in the presence of calcium ions. We incorporated CaCO{sub 3} particles into the membranes to enhance their bioactivity and mechanical properties. Infrared spectroscopy and X-ray diffraction data confirmed CaCO{sub 3} incorporation into the polymeric matrix. We tested the bioactivity of the samples by immersing them in a solution that mimics the ionic composition and pH of the human body fluid. The hybrid membranes generated hydroxyapatite, as attested by X-ray diffraction data. Scanning electron and atomic force microscopies aided investigation of membrane topography before and after CaCO{sub 3} deposition. The wettability and surface free energy, evaluated by contact angle measures, increased in the presence of CaCO{sub 3} particles. These parameters are important for membrane implantation in the body. Moreover, membrane stiffness was up to 110% higher in the presence of the inorganic particles, as revealed by Young's modulus. - Highlights: • Hybrid kappa and iota carrageenan-CaCO{sub 3} membranes were formed. • The hybrid membrane's origin hydroxyapatite after exposure to simulated body fluid • The carrageenan's specificity to bind Ca{sup 2+} ions tailors the surface properties.

Poly-thiosemicarbazide membrane for gold recovery

KAUST Repository

Villalobos, Luis Francisco; Yapici, Tahir; Peinemann, Klaus-Viktor

2014-01-01

A novel polymeric membrane adsorber with a high density of adsorption sites that can selectively capture Au(III) ions, is proposed as an efficient alternative to recover gold from dilute solutions. Poly-thiosemicarbazide (PTSC), a polymer

A Functional Core of IncA Is Required for Chlamydia trachomatis Inclusion Fusion.

Science.gov (United States)

Weber, Mary M; Noriea, Nicholas F; Bauler, Laura D; Lam, Jennifer L; Sager, Janet; Wesolowski, Jordan; Paumet, Fabienne; Hackstadt, Ted

2016-04-01

Chlamydia trachomatis is an obligate intracellular pathogen that is the etiological agent of a variety of human diseases, including blinding trachoma and sexually transmitted infections. Chlamydiae replicate within a membrane-bound compartment, termed an inclusion, which they extensively modify by the insertion of type III secreted proteins called Inc proteins. IncA is an inclusion membrane protein that encodes two coiled-coil domains that are homologous to eukaryotic SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) motifs. Recent biochemical evidence suggests that a functional core, composed of SNARE-like domain 1 (SLD-1) and part of SNARE-like domain 2 (SLD-2), is required for the characteristic homotypic fusion of C. trachomatis inclusions in multiply infected cells. To verify the importance of IncA in homotypic fusion in Chlamydia, we generated an incA::bla mutant. Insertional inactivation of incA resulted in the formation of nonfusogenic inclusions, a phenotype that was completely rescued by complementation with full-length IncA. Rescue of homotypic inclusion fusion was dependent on the presence of the functional core consisting of SLD-1 and part of SLD-2. Collectively, these results confirm in vitro membrane fusion assays identifying functional domains of IncA and expand the genetic tools available for identification of chlamydia with a method for complementation of site-specific mutants. Chlamydia trachomatis replicates within a parasitophorous vacuole termed an inclusion. The chlamydial inclusions are nonfusogenic with vesicles in the endocytic pathway but, in multiply infected cells, fuse with each other to form a single large inclusion. This homotypic fusion is dependent upon the presence of a chlamydial inclusion membrane-localized protein, IncA. Specificity of membrane fusion in eukaryotic cells is regulated by SNARE (soluble N-ethylmaleimide sensitive factor attachment receptor) proteins on the cytosolic face of vesicles and target

Binding and assembly of actin filaments by plasma membranes from dictyostelium discoideum

International Nuclear Information System (INIS)

Schwartz, M.A.; Luna, E.J.

1986-01-01

The binding of native, 125 I-Bolton-Hunter-labeled actin to purified Dictyostelium discoideum plasma membranes was measured using a sedimentation assay. Binding was saturable only in the presence of the actin capping protein, gelsolin. The binding curves were sigmoidal, indicating positive cooperativity at low actin concentrations. This cooperativity appeared to be due to actin-actin associations during polymerization, since phalloidin converted the curve to a hyperbolic shape. This membrane-bound actin stained with rhodamine-phalloidin and was cross-linked by m-maleimidobenzoyl succinimide ester, a bifunctional cross-linker, into multimers with the same pattern observed for cross-linked F-actin. The authors conclude that D. discoideum plasma membranes bind actin specifically and saturably and that these membranes organize actin into filaments below the normal critical concentration for polymerization. This interaction probably occurs between multiple binding sites on the membrane and the side of the actin filament, and may be related to the clustering of membrane proteins

Newly Developed Ceramic Membranes for Dehydration and Separation of Organic Mixtures by Pervaporation

NARCIS (Netherlands)

Gemert, van R.W.; Cuperus, F.P.

1995-01-01

Polymeric pervaporation membranes sometimes show great variety in performance when they are alternately used for different solvent mixtures. In addition, membrane stability in time is a problem in case of some solvents. Therefore, newly developed ceramic silica membranes with a 'dense' top layer

Membrane Materials and Technology for Xylene Isomers Separation and Isomerization via Pervaporation

KAUST Repository

Bilaus, Rakan

2014-01-01

technology’s high energy intensity has become a growing concern. Membrane separation technology is a potential low-energy alternative. Polymeric membranes were investigated in a pervaporation experiment to separate xylene isomers. Polymers of intrinsic

Progress in surface and membrane science

CERN Document Server

Danielli, J F; Cadenhead, D A

1973-01-01

Progress in Surface and Membrane Science, Volume 6 covers the developments in the study of surface and membrane science. The book discusses the progress in surface and membrane science; the solid state chemistry of the silver halide surface; and the experimental and theoretical aspects of the double layer at the mercury-solution interface. The text also describes contact-angle hysteresis; ion binding and ion transport produced by neutral lipid-soluble molecules; and the biophysical interactions of blood proteins with polymeric and artificial surfaces. Physical chemists, biophysicists, and phys

Comparison of the performance of natural latex membranes prepared with different procedures and PTFE membrane in guided bone regeneration (GBR) in rabbits.

Science.gov (United States)

Moura, Jonas M L; Ferreira, Juliana F; Marques, Leonardo; Holgado, Leandro; Graeff, Carlos F O; Kinoshita, Angela

2014-09-01

This work assessed the performance of membranes made of natural latex extracted from Hevea brasiliensis prepared with three different methods: polymerized immediately after collection without the use of ammonia (L1); polymerized after preservation in ammonia solution (L2); and polymerized after storage in ammonia, followed by Soxhlet technique for the extraction of substances (L3). Polytetrafluoroethylene (PTFE) membrane was used as control. Two 10-mm diameter bone defects were surgically made in the calvaria of thirty adult male New Zealand rabbits. Defects (total n = 60) were treated with guided bone regeneration (GBR) using L1, L2, L3 or PTFE membranes (n = 15 for each membrane). Ten animals were euthanized after 7, 20 and 60 days postoperatively so that five samples (n = 5) of each treatment were collected at each time, and bone regeneration was assessed microscopically. The microscopic analysis revealed defects filled with blood clot and new bone formation at the margins of the defect in all 7-day samples, while 20-day defects were mainly filled with fibrous connective tissue. After 60 days defects covered with L1 membranes showed a significantly larger bone formation area in comparison to the other groups (P PTFE membranes was also investigated in six additional rabbits. The animals were subjected to the same surgical procedure for the confection of one 10-mm diameter bone defect that was treated with L1 (n = 3) or PTFE (n = 3). Fifty-three days later, a second surgery was performed to make a second defect, which was treated with the same type of membrane used in the first surgery. Seven days later, the animals were euthanized and samples analyzed. No differences among L1 and PTFE samples collected from sensitized and non-sensitized animals were found (P > 0.05, Kruskal-Wallis). Therefore, the results demonstrated that latex membranes presented performance comparable to PTFE membranes, and that L1 membranes induced higher bone formation. L1 and

Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.; Suzuki, M.; Adachi, S.

1983-01-01

Immobilization of antibodies and enzyme-labeled antibodies by radiation polymerization at low temperatures was studied. The antibody activity of antibody was not affected by irradiation at an irradiation dose of below 8 MR and low temperatures. Immobilization of peroxidase-labeled anti-rabbit IgG goat IgG, anti-peroxidase, peroxidase, and anti-alpha-fetoprotein was carried out with hydrophilic and hydrophobic monomers. The activity of the immobilized enzyme-labeled antibody membranes varied with the thickness of the membranes and increased with decreasing membrane thickness. The activity of the immobilized antibody particles was varied by particle size. Immobilized anti-alpha-fetoprotein particles and membranes can be used for the assay of alpha-fetoprotein by the antigen-antibody reaction, such as a solid-phase sandwich method with high sensitivity

Nuclear Glycogen Inclusions in Canine Parietal Cells.

Science.gov (United States)

Silvestri, S; Lepri, E; Dall'Aglio, C; Marchesi, M C; Vitellozzi, G

2017-05-01

Nuclear glycogen inclusions occur infrequently in pathologic conditions but also in normal human and animal tissues. Their function or significance is unclear. To the best of the authors' knowledge, no reports of nuclear glycogen inclusions in canine parietal cells exist. After initial observations of nuclear inclusions/pseudoinclusions during routine histopathology, the authors retrospectively examined samples of gastric mucosa from dogs presenting with gastrointestinal signs for the presence of intranuclear inclusions/pseudoinclusions and determined their composition using histologic and electron-microscopic methods. In 24 of 108 cases (22%), the authors observed various numbers of intranuclear inclusions/pseudoinclusions within scattered parietal cells. Nuclei were characterized by marked karyomegaly and chromatin margination around a central optically empty or slightly eosinophilic area. The intranuclear inclusions/pseudoinclusions stained positive with periodic acid-Schiff (PAS) and were diastase sensitive, consistent with glycogen. Several PAS-positive/diastase-sensitive sections were further examined by transmission electron microscopy, also using periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining to identify polysaccharides. Ultrastructurally, the nuclear inclusions were composed of electron-dense particles that were not membrane bound, without evidence of nuclear membrane invaginations or cytoplasmic organelles in the nuclei, and positive staining with PA-TCH-SP, confirming a glycogen composition. No cytoplasmic glycogen deposits were observed, suggesting that the intranuclear glycogen inclusions were probably synthesized in loco. Nuclear glycogen inclusions were not associated with gastritis or colonization by Helicobacter-like organisms ( P > .05). Our findings suggest that nuclear glycogen inclusions in canine parietal cells could be an incidental finding. Nevertheless, since nuclear glycogen is present in several pathologic

Fabrication of cell outer membrane mimetic polymer brush on polysulfone surface via RAFT technique

International Nuclear Information System (INIS)

Ma Qian; Zhang Hui; Zhao Jiang; Gong Yongkuan

2012-01-01

Highlights: ► Cell membrane mimetic antifouling polymer brush was grown on polysulfone surface. ► Graft density and polymerization degree were calculated from XPS results. ► Water contact angle measurements showed an extremely hydrophilic surface. ► Platelet adhesion and protein adsorption results suggested excellent antifouling ability. - Abstract: Cell membrane mimetic antifouling polymer brush was grown on polysulfone (PSF) membrane by surface-induced reversible addition–fragmentation chain transfer (RAFT) polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC). The RAFT agent immobilized PSF substrate was prepared by successive chloromethylation, amination with ethylenediamine (EDA) and amidation of the amine group of grafted EDA with the carboxylic group of 4-cyanopentanoic acid dithiobenzoate (CPAD). The surface RAFT polymerization of MPC was initiated in aqueous solution by 4,4′-azobis-4-cyanopentanoic acid (ACPA). The formation of PMPC brush coating is evidenced by X-ray photoelectron spectroscopy and water contact angle measurements. The degree of polymerization of PMPC and the polymer grafting density were calculated from the high resolution XPS spectra. The platelet adhesion and protein adsorption results showed that the PMPC-grafted PSF surface has excellent antifouling ability to resist platelet adhesion completely and suppress protein adsorption significantly. This biomimetic and bio-friendly surface RAFT polymerization strategy could be promising for a variety of biomedical applications.

Crystal nuclei templated nanostructured membranes prepared by solvent crystallization and polymer migration

Science.gov (United States)

Wang, Bo; Ji, Jing; Li, Kang

2016-09-01

Currently, production of porous polymeric membranes for filtration is predominated by the phase-separation process. However, this method has reached its technological limit, and there have been no significant breakthrough over the last decade. Here we show, using polyvinylidene fluoride as a sample polymer, a new concept of membrane manufacturing by combining oriented green solvent crystallization and polymer migration is able to obtain high performance membranes with pure water permeation flux substantially higher than those with similar pore size prepared by conventional phase-separation processes. The new manufacturing procedure is governed by fewer operating parameters and is, thus, easier to control with reproducible results. Apart from the high water permeation flux, the prepared membranes also show excellent stable flux after fouling and superior mechanical properties of high pressure load and better abrasion resistance. These findings demonstrate the promise of a new concept for green manufacturing nanostructured polymeric membranes with high performances.

New membrane materials for potassium-selective ion-sensitive field-effect transistors

NARCIS (Netherlands)

van der Wal, P.D.; van der Wal, Peter D.; Skowronska-Ptasinska, Maria; van den Berg, Albert; Bergveld, Piet; Sudholter, Ernst; Sudholter, Ernst J.R.; Reinhoudt, David

1990-01-01

Several polymeric materials were studied as membrane materials for potassium-selective ion-sensitive field-effect transistors (ISFETs) to overcome the problems related with the use of conventional plasticized poly(vinyl chloride) membranes casted on ISFET gate surfaces. Several acrylate materials,

Radiation induced graft copolymerization for preparation of cation exchange membranes: a review

International Nuclear Information System (INIS)

Mohamed Mahmoud Nasef; Hamdani Saidi; Hussin Mohd Nor

1999-01-01

Cation exchange membranes are regarded as the ideal solid polymer electrolyte materials for the development of various electrochemical energy conversion applications where significant improvements in the current density are required. Such membranes require special polymers and preparation techniques to maintain high chemical , mechanical and thermal stability in addition to high ionic conductivity and low resistance. A lot of different techniques have been proposed in the past to prepare such membranes. Radiation-induced graft copolymerization provides an attractive ft method for modification of chemical and physical properties of polymeric materials and is of particular interest in achieving specially desired cation exchange membranes as well as excellent membrane properties. This is due to the ability to control the membrane compositions as well as properties by proper selection of grafting conditions. Therefore numerous parameters have to be investigated to properly select the right polymeric materials, radiation grafting technique and the grafting conditions to be employed. In this paper a state-of-the-art of radiation-induced graft copolymerization for preparation of cation exchange membranes and their applications are briefly reviewed. (Author)

Surface Modifications of Support Partitions for Stabilizing Biomimetic Membrane Arrays

DEFF Research Database (Denmark)

Perry, Mark; Hansen, Jesper Schmidt; Jensen, Karin Bagger Stibius

2011-01-01

with a high signal-to-noise (s/n) ratio. We demonstratesd this by reconstituting gA and α-hemolysin (α-HL) into BLM arrays. The improvement in membrane array lifetime and s/n ratio demonstrates that surface plasma polymerization of the supporting partition can be used to increase the stability of biomimetic......Black lipid membrane (BLM) formation across apertures in an ethylene tetra-fluoroethylene (ETFE) partition separating two aqueous compartments is an established technique for the creation of biomimetic membranes. Recently multi-aperture BLM arrays have attracted interest and in order to increase...... BLM array stability we studied the effect of covalently modifying the partition substrate using surface plasma polymerization with hydrophobic n-hexene, 1-decene and hexamethyldisiloxane (HMDSO) as modification groups. Average lifetimes across singlesided HMDSO modified partitions or using 1-decene...

Radio-chemical applications of functionalized membranes

International Nuclear Information System (INIS)

Pandey, Ashok K.

2011-01-01

Functionalized polymer membranes have many potential applications as they are task specific. We have developed many functionalized membranes like polymer inclusion membranes, pore-filled membranes and nano-membranes. Radiotracers and other methods have been used to understand the diffusional-transport properties of the Nafion-117 membrane as well as home-made membranes. These membranes have been used to develop novel analytical and separation methods for toxic metal ions and radionuclides. In this talk, an overview of our work on functionalized membrane is presented. (author)

Adsorbent filled polymeric membranes : applications to pervaporation and gas separation

NARCIS (Netherlands)

Duval, Jean-Marc

1993-01-01

Nowadays research in membrane technology aims at improving the efficiency of the separation process to make it more competitive in comparison to conventional separation techniques. The improvement of the membrane material is a way to achieve this goal, especially in the case of pervaporation and gas

Novel ceramic-polymer composite membranes for the separation of liquid waste. Annual progress report, September 15, 1996 - September 14, 1997

International Nuclear Information System (INIS)

Cohen, Y.

1997-01-01

'The project on ceramic-supported polymer membranes focuses on the development of a novel class of membranes for the separation of organics from both organic-aqueous and organic-organic mixtures, Theses membranes are fabricated by a graft polymerization process where polymer chains are grown onto the surface of a ceramic support membrane. The surface graft polymerization process, developed at UCLA, results in the formation of a thin polymer layer covalently bonded to the membrane pore surface as a layer of terminally anchored polymeric chains. Through the selection of the polymer most appropriate for the desired separation task, the graft polymerized surface layer can be synthesized to impart specific separation properties to the membrane. It is expected that this project will lead to the demonstration of a new technology for the tailor design of a new class of selective and robust ceramic-supported polymer membranes. This new approach will allow the rapid deployment of task-specific membranes for the separation of waste constituents for subsequent recovery, treatment or disposal. Progress to date includes the preparation of successful silica-polyvinylpyrrolidone (PVP) membrane for the treatment of oil-in-water emulsions and a silica-polyvinylacetate (PVAc) pervaporation membrane for the separation of organics from water. Current work is ongoing to study the performance of the pervaporation membrane for the removal of chlorinated organics from water and to develop a pervaporation membrane for organic-organic separation. In another aspect of the study, the authors are studying the hydrophilic PVP CSP membrane for oil-in-water emulsion treatment with the goal of determining the optimal membrane polymer surface structure as a function of various operating conditions (e.g., tube-side Reynolds number and transmembrane pressure), Work is also in progress to characterize the polymer layer by AFM and internal reflection FTIR, and to model the conformation of the polymer

From classical polymerizations in solution towards radio-induced polymerizations controlled in confined space

International Nuclear Information System (INIS)

Dubois-Clochard, M.-C.

2013-01-01

The manuscript of Mrs Marie-Claude Dubois-Clochard reports on the main results obtained in synthesis and structuration of functional polymers at the nano-scale. If the synthesis of functional polymers is the basic of the presented studies, the chronological order of her research activities from 1995 to 2013 shows an evolution from classical polymerizations in solution towards radio-induced polymerizations in confined space controlled by RAFT mechanism. The innovation is about the development of new objects made of polymers and organic/inorganic composites designed at the nano-scale to bring original physical and physico-chemical properties. Three applied fields stand out: Energy-Environment (Engines, Fuel cells, Sensors for water quality), Health (Nano-vector for tumour therapies and imaging, Ion and molecules translocation through a single nano-pore in a polymer membrane) and Nano-technologies (Magnetoresistance of a single magnetic nano-wire). Noteworthy results are: - the setting up of bi-langmuirian adsorption isotherm equations at solid/hydrocarbon interface for macromolecules at low concentrations, and, at high concentration, particular behaviour of reorganisation of these identical macromolecules, not in alternative layers but in reverse hemi-micelles formation. - the synthesis of a novel pH-degradable polymer allowing an hydrolytic degradation from pH 7.4 (Sang) to pH 5.5 (Intracellular lysosome) to deliver drugs into tumor cells (Sante). - the radiation-induced grafting-through process in solid polymers showed by a cooperative effect of solvent/growing polymer chains into fluoropolymers. - the synthesis of bi-functional nano-porous polymer track-etched membranes having a functionality in the pores and another on the surface. This membrane, after changing in electrode by simple metallization, has been the subject of valorisation projects to a start-up creation and/or a technological transfer for the development of a sensor able to detect heavy metals ions

Binderless electrodes for high-temperature polymer electrolyte membrane fuel cells

DEFF Research Database (Denmark)

Fernandez, Santiago Martin; Li, Qingfeng; Steenberg, Thomas

2014-01-01

A new electrode concept was proved with no polymeric binder in the catalyst layer for acid-doped polybenzimidazole (PBI) membrane fuel cells. It shows that a stable interface between the membrane and the catalyst layer can be retained when a proton conducting acid phase is established. The absenc...

Increasing the Performance of Vacuum Membrane Distillation Using Micro-Structured Hydrophobic Aluminum Hollow Fiber Membranes

Directory of Open Access Journals (Sweden)

Chia-Chieh Ko

2017-04-01

Full Text Available This study develops a micro-structured hydrophobic alumina hollow fiber with a high permeate flux of 60 Lm−2h−1 and salt rejection over 99.9% in a vacuum membrane distillation process. The fiber is fabricated by phase inversion and sintering, and then modified with fluoroalkylsilanes to render it hydrophobic. The influence of the sintering temperature and feeding temperature in membrane distillation (MD on the characteristics of the fiber and MD performance are investigated. The vacuum membrane distillation uses 3.5 wt % NaCl aqueous solution at 70 °C at 0.03 bar. The permeate flux of 60 Lm−2h−1 is the highest, compared with reported data and is higher than that for polymeric hollow fiber membranes.