scholarly journals Specific Structure and Properties of Composite Membranes Based on the Torlon® (Polyamide-imide)/Layered Perovskite Oxide

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1142
Author(s):  
Alexandra Pulyalina ◽  
Valeriia Rostovtseva ◽  
Iana Minich ◽  
Oleg Silyukov ◽  
Maria Toikka ◽  
...  
Keyword(s):  
Membrane Surface ◽  
Composite Membranes ◽  
Contact Angles ◽  
Specific Structure ◽  
Perovskite Oxide ◽  
Layered Perovskite ◽  
Perovskite Type ◽  
Acetate Mixture ◽  
High Separation ◽  
Ethyl Acetate Mixture

The use of perovskite-type layered oxide K2La2Ti3O10 (Per) as a modifier of the Torlon® polyamide-imide (PAI) membrane has led to the formation of an specific structure of a dense nonsymmetrical film, namely, a thin perovskite-enriched layer (3–5 μm) combined with the polymer matrix (~30 μm). The PAI/Per membrane structure was studied by SEM in combination with energy dispersive microanalysis of the elemental composition which illustrated different compositions of top and bottom surfaces of the perovskite-containing membranes. Measurement of water and alcohol contact angles and calculation of surface tension revealed hydrophilization of the membrane surface enriched with perovskite. The transport properties of the nonsymmetrical PAI/Per membranes were studied in the pervaporation of ethanol‒ethyl acetate mixture. The inclusion of 2 wt.% Per in the PAI gives a membrane with a high separation factor and increased total flux.

scholarly journals New Synthetic Methods of Novel Nanoporous Polycondensates and Excellent Oxygen Permselectivity of Their Composite Membranes

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 859
Author(s):  
Yu Zang ◽  
Toshiki Aoki ◽  
Masahiro Teraguchi ◽  
Takashi Kaneko ◽  
Hongge Jia ◽  
...  
Keyword(s):  
Contact Angle ◽  
Upper Bound ◽  
Oxygen Permeability ◽  
Membrane Surface ◽  
Composite Membranes ◽  
Synthetic Methods ◽  
Preparation Methods ◽  
First Time

Two kinds of novel nanoporous polycondensates (sc(Rf)) have been synthesized by two new preparation methods consisting of polycondensation and highly selective photocyclicaromataization of 1/3 helical cis-cis polyphenylacetylenes with polymerizable groups. By the original methods, new well-defined sheet polymers having nanopores or nanospaces have been synthesized for the first time. Their composite membranes, containing small amounts (1.0 wt%) of sc(Rf), had ultrahigh oxygen permeability (Po2 > 1000 barrer), and their plots were beyond the Robeson’s upper bound line in the graph of oxygen permselectivity (α = Po2/PN2) versus Po2. Both α and Po2 values were enhanced by adding only small amounts (1.0 wt%) of sc(Rf). One of the sc(Rf)s synthesized on the base membrane surface showed the best performance, i.e., Po2 = 5300 barrer and α = 2.5. The membrane surface was effectively covered by sc(Rf), judging from the contact angle values. It is thought that nanopores and nanospaces created in and between sc(Rf) molecules played an important role for the enhancement of both α and Po2/PN2.

scholarly journals ZnO Microfiltration Membranes for Desalination by a Vacuum Flow-Through Evaporation Method

Membranes ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 156 ◽  
Author(s):  
Shailesh Dangwal ◽  
Ruochen Liu ◽  
Lyndon D. Bastatas ◽  
Elena Echeverria ◽  
Chengqian Huang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Water Flux ◽  
Atomic Layer ◽  
Rejection Rate ◽  
Contact Angles ◽  
Transfer Resistance ◽  
Membrane Pore ◽  
Evaporation Method ◽  
Flow Through

ZnO was deposited on macroporous α-alumina membranes via atomic layer deposition (ALD) to improve water flux by increasing their hydrophilicity and reducing mass transfer resistance through membrane pore channels. The deposition of ZnO was systemically performed for 4–128 cycles of ALD at 170 °C. Analysis of membrane surface by contact angles (CA) measurements revealed that the hydrophilicity of the ZnO ALD membrane was enhanced with increasing the number of ALD cycles. It was observed that a vacuum-assisted ‘flow-through’ evaporation method had significantly higher efficacy in comparison to conventional desalination methods. By using the vacuum-assisted ‘flow-through’ technique, the water flux of the ZnO ALD membrane (~170 L m−2 h−1) was obtained, which is higher than uncoated pristine membranes (92 L m−2 h−1). It was also found that ZnO ALD membranes substantially improved water flux while keeping excellent salt rejection rate (>99.9%). Ultrasonic membrane cleaning had considerable effect on reducing the membrane fouling.

A New Flux, NaCl, to Grow Layered Perovskite-Type Na2Ca2Nb4O13Crystals

1999 ◽  
Vol 28 (10) ◽  
pp. 1011-1012 ◽  
Author(s):  
Shuji Oishi ◽  
Masaya Kanoh ◽  
Nobuo Ishizawa
Keyword(s):  
Layered Perovskite ◽  
Perovskite Type

scholarly journals Crystal structures of isotypic poly[bis(benzimidazolium) [tetra-μ-iodido-stannate(II)]] and poly[bis(5,6-difluorobenzimidazolium) [tetra-μ-iodido-stannate(II)]]

2014 ◽  
Vol 70 (10) ◽  
pp. 178-182 ◽  
Author(s):  
Iwan Zimmermann ◽  
Tony D. Keene ◽  
Jürg Hauser ◽  
Silvio Decurtins ◽  
Shi-Xia Liu
Keyword(s):  
Hydrogen Bonds ◽  
Point Group ◽  
Van Der Waals Interactions ◽  
Group Symmetry ◽  
Layered Perovskite ◽  
Out Of Plane ◽  
Related Compounds ◽  
Perovskite Type ◽  
Inorganic Layers ◽  
Perovskite Type Structure

The isostructural title compounds, {(C7H7N2)2[SnI4]}n, (1), and {(C7H5F2N2)2[SnI4]}n, (2), show a layered perovskite-type structure composed of anionic {[SnI4]2−}nsheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-difluorobenzimidazolium cations, respectively. These planar organic heterocycles mainly form N—H...I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octahedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn—I—Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N—H...I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals interactions.

scholarly journals Structural and electrical properties of layered perovskite type Pr2Ti2O7: experimental and theoretical investigations

2015 ◽  
Vol 3 (17) ◽  
pp. 4570-4584 ◽  
Author(s):  
Sadequa J. Patwe ◽  
Vasundhara Katari ◽  
Nilesh P. Salke ◽  
Sudhanshu K. Deshpande ◽  
Rekha Rao ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Electrical Properties ◽  
Spectroscopic Studies ◽  
Layered Perovskite ◽  
Raman Spectroscopic ◽  
Structural And Electrical Properties ◽  
Theoretical Investigations ◽  
Higher Temperature ◽  
Perovskite Type

In this communication we report the details of the structural and thermal properties of monoclinic layered perovskite type Pr2Ti2O7 (PTO) using ambient to higher temperature XRD and Raman spectroscopic studies.

Chromatography Using Ternary Water–Acetonitrile–Ethyl Acetate Mixture as a Carrier Solution on a Microchip Incorporating Microchannels

2012 ◽  
Vol 41 (11) ◽  
pp. 1448-1450 ◽  
Author(s):  
Takafumi Matsuda ◽  
Naoya Jinno ◽  
Kenichi Yamashita ◽  
Hideaki Maeda ◽  
Akihiro Arai ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Carrier Solution ◽  
Acetate Mixture ◽  
Ethyl Acetate Mixture

scholarly journals The Study on the Reaction Order and Kinetics of Total Oxidation Reaction of m-xylene over LaMnO3 Perovskite Catalyst

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Tran Thi Thu Huyen ◽  
Dang Thi Minh Hue ◽  
Nguyen Thi Tuyet Mai ◽  
Tran Thi Luyen ◽  
Nguyen Thi Lan
Keyword(s):  
Catalytic Activity ◽  
Reaction Order ◽  
Catalytic Properties ◽  
Sol Gel ◽  
Deep Oxidation ◽  
Perovskite Oxide ◽  
Mixed Metal Oxide ◽  
Total Oxidation ◽  
Kinetics Of ◽  
Perovskite Type

Gases of m-xylene is one of the popurlar toxic pollutants in the exhaust gases, it is emitted into the environment from factories and engines because the fuel in the engine does not burn completely. The best solution in order to remove this toxic gases of m-xylene to protect the environment is transforming them completely into CO2 and H2O by catalysts. Perovskite of LaMnO3 is one of the catalysts that was synthesized and studied the catalytic properties in total oxidation of m-xylene in our previous report. Obtained results showed that the LaMnO3 perovskite has good catalytic characterizations such as large surface area and the amount of α-oxygen adsorbed on the catalyst is large too. So, it exhibits a good catalytic activity in total oxidation of m-xylene at relatively low reaction temperature. In present work, the reaction order  and kinetics of this reaction are determined. The obtained results demonstrated that the reaction order value with respect to m-xylene is equal to about 1, to oxygene is proximately equal to 0 and the order of reaction is equal to about 1. Based on reaction order data, it was thought that the pathway of m-xylene oxidation by air oxygen  over LaMnO3 may be followed through which the Langmuir - Hinshelwood mechanism. Keywords Catalyst, perovskite, oxidation, m-xylene, kinetics References [1] Penã M.A and Fierro J.L.G (2001), << Chemical Stuctures and Performance of Perovskite Oxide>>, Chem. Rev, 101, pp 1981-2018. [2] Seiyama T., Yamazoe N. and Eguchi K. (1985), <<Characterization and Activity of some Mixed Metal Oxide Catalysts>>, Ind. Eng. Chem. Prod. Res. Dev., 24, pp. 19-27.[3] [3] Van Santen R. A., Neurock M. (2006), Molecular Heterogeneous catalysis, Wiley – VCH, pp.62-244. [4] Petrovics, Terlecki - Baricevic A., Karanovic Lj., Kirilov - Stefanov P. , Zdujic M., Dondur V., Paneva D., Mitov I., Rakic V. (2008), <<LaMO3 (M = Mg, Ti, Fe) perovskite type oxides : Preparation, Characterization and Catalytic Properties in Methane deep Oxidation>>, Appl. Catal. B, Env., 79, pp. 186-198. [5] Spinicci R., Tofanari A., Faticanti M., Pettiti I. and Porta P. (2001), <<Hexane Total Oxidation on LaMO3 (M = Mn, Co, Fe) perovskite-type oxides>>, J. Mole. Catal., 176, pp. 247-252. [6] Trần Thị Thu Huyền, Nguyễn Thị Minh Hiền, Nguyễn Hữu Phú (2006), <<Study on the preparation of perovskite oxides La1-xSrxMnO3 (x = 0; 0,3; 0,5) by sol - gel citrate method and their catalytic activity for m-xylene toltal oxidation>>, Hội nghị xúc tác và hấp phụ toàn quốc lần thứ IV, Tp. Hồ Chí Minh, Tr. 477-482.[7] Trần Thị Thu Huyền, Nguyễn Thị Minh Hiền, Nguyễn Hữu Phú (2009), <<Nghiên cứu động học của phản ứng oxi hóa hoàn toàn m-xylen trên các xúc tác perovskit LaMnO3 và La0,7A0,3MnO3 (A = Sr, Ca, Mg)>>, Tạp chí Hóa học, T.47 (6A), Tr 132-136.[8] Geoffrey C. Bond, Catherine Louis, David T. Thompson (2006), <<Catalysis by Gold>>, Catalytic Science Series-Vol.6.

scholarly journals Dual Functional Ultrafiltration Membranes with Enzymatic Digestion and Thermo-Responsivity for Protein Self-Cleaning

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 85 ◽  
Author(s):  
Anbharasi Vanangamudi ◽  
Ludovic Dumée ◽  
Mikel Duke ◽  
Xing Yang
Keyword(s):  
Surface Engineering ◽  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Surface Protein ◽  
Composite Membranes ◽  
Enzymatic Digestion ◽  
Combined Effect ◽  
Functional Sites ◽  
Nylon 6,6 ◽  
Self Cleaning

Controlling surface–protein interaction during wastewater treatment is the key motivation for developing functionally modified membranes. A new biocatalytic thermo-responsive poly vinylidene fluoride (PVDF)/nylon-6,6/poly(N-isopropylacrylamide)(PNIPAAm) ultrafiltration membrane was fabricated to achieve dual functionality of protein-digestion and thermo-responsive self-cleaning. The PVDF/nylon-6,6/PNIPAAm composite membranes were constructed by integrating a hydrophobic PVDF cast layer and hydrophilic nylon-6,6/PNIPAAm nanofiber layer on to which trypsin was covalently immobilized. The enzyme immobilization density on the membrane surface decreased with increasing PNIPAAm concentration, due to the decreased number of amine functional sites. An ultrafiltration study was performed using the synthetic model solution containing BSA/NaCl/CaCl2, where the PNIPAAm containing biocatalytic membranes demonstrated a combined effect of enzymatic and thermo-switchable self-cleaning. The membrane without PNIPAAm revealed superior fouling resistance and self-cleaning with an RPD of 22%, compared to membranes with 2 and 4 wt % PNIPAAm with 26% and 33% RPD, respectively, after an intermediate temperature cleaning at 50 °C, indicating that higher enzyme density offers more efficient self-cleaning than the combined effect of enzyme and PNIPAAm at low concentration. The conformational volume phase transition of PNIPAAm did not affect the stability of immobilized trypsin on membrane surfaces. Such novel surface engineering design offer a promising route to mitigate surface–protein contamination in wastewater applications.

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